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SWP272171(35)
4%R CITY OF RENTON "LL Planning/Building/Public Works Department Earl Clymer, Mayor Gregg Zimmerman P.E., Administrator June 16, 1994 Tracey McKenzie, Project Manager Parametrix, Inc 5808 Lake Washington Blvd. NE Kirkland, WA 98033-7350 SUBJECT: WETLAND MITIGATION BANKING PROGRAM AND PLAN COMMENTS TO DRAFT CHAPTERS 1-6 DATED NOVEMBER 1993 Dear Tracey: Enclosed is a copy of portions of the draft chapters 1-6 of the Wetland Mitigation Banking Program and Plan dated November 1993 with review comments noted in the text. No comments were made on the portions of the draft which are not included. A specific concern is the lack of information in the plan on the existing hydrologic conditions (quantity and quality) for the mitigation banking sites and adjacent areas, such as exhibits of the tributary area and quantitative estimates of the existing and potential water budget. Much information has been developed for the Black River Basin from which data may be calculated or interpolated to the mitigation sites. These estimates would be useful in the preliminary planning phase of the project and would be refined for final design once monitoring systems are installed and physical data is collected in the field. I am also concerned with the size of the plan. The number of pages may be reduced by removing repetitive text, relying more on references to other sections in the plan or separate documents, reformatting the document so that supplementary information is placed in a separately bound appendix, and combining figures were possible. Please call me when you have reviewed the enclosures to discuss the comments and the next steps for the project at (206) 277-5547. Your assistance is appreciated. Sincerely, Scott Woodbury, Proje3t Manager Surface Water Utility H:DOCS:94-372:SSW:ps CC: Ron Straka Enclosures i 200 Mill Avenue South - Renton, Washington 98055 Fl D si6� r6A,4111 to Dmft City of Renton Wetland Mitgation Banking Program ♦ R ♦ o Q1 S 1993 CITY OF RENTON WETLAND MITIGATION BANKING PROGRAM AND PLAN Prepared for CITY OF RENTON 200 Mill Avenue Renton, Washington 98055 Prepared by PARAMETRIX, INC. 5808 Lake Washington Blvd. NE Kirkland, Washington 98033 I y'l ty �Ea�f- .Die�re�e�-�993. TABLE OF CONTENTS Page EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v CHAPTER 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 CHAPTER 2. GOAL, OBJECTIVES, AND POLICIES OF THE MITIGATION BANKING PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 GOAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 POLICIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 HAPTER 3. POLICY ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.1 POLICY ISSUE 1: Should the City be Eligible to Use the Mitigation Banking Sites for Public Projects? . . . . . . . . . . . . . . . . . . . 10 3.1.1 Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.1.2 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.1.3 Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.2 POLICY ISSUE 2: Should the Mitigation Banking Sites be Used for Impacts to Category 1 and 2 Wetlands, or Only for Projects Impacting Category 3 Wetlands? . . . . . . . . . . . . . . . . . . . . . 13 3.2.1 Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2.2 Options: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2.3 Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 (� 3.3 POLICY ISSUE 3: Should the Mitigation Banking Sites be Used for Impacts to V 15 0- Wetlands That are Less Than 1 Acre, or for Projects Impacting Wetlands Less Than 1 Acre or 1 Acre or Greater C. to in Size? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.3.1 Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1 kt#aStlr 3.3.2 Options: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.3.3 Recommendation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 W 3.4 POLICY ISSUE 4: Should the City be Solely Responsible for Administrative and Technical Management of the Mitigation Banking Program and Mitigation Banking Sites? . . . . . . . . . 20 w 3.4.1 Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 41 3.4.2 Options . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 nt 3.4.3 Recommendation 22 4Y Parametrix, Inc. i City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtigpin 3.5 POLICY ISSUE 5: Should the City Consider Exempting Category 3 Wetlands From the Sequencing Process (i.e., Avoidance, Minimization Compensation) Currently Required by the City's Interim Wetlands Ordinance? . . . . . . . . . . . 23 3.5.1 Issue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.5.2 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 ��✓ 3.5.3 Recommendation 24 3.6 POLICY ISSUE 6: Should the City Consider Modifying the Existing Interim Wetlands Management Ordinance to Recognize GMT Enha_cement as an Acceptable Form of Compensatory Mitigation? . . . . . . . 25 3.6.1 Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.6.2 Recommendation 26 �kl`dHS CHAPTER 4. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 s«� 4.1 ELIGIBILITY CRITERIA 1: ,Odes the Proposed Project Iy City Wetland Management Ordinance t (Ordinance Number 4346)? . . . . . . . 28 4.2 ELIGIBILITY CRITERIA 2: Is the Proposed Project Located Within the fA 1. Black River Drainage Basin? . . . . . . 30 �� 4.3 ELIGIBILITY CRITERIA 3: What is the Size and Category of the Wetland That May be Affected? . . . . 30 4.4 ELIGIBILITY CRITERIA 4: Is On-site Mitigation Feasible? . . . . . 30 CHAPTER 5. REGULATORY REQUIREMENTS TO IMPLEMENT THE MITIGATION BANKING PROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 CHAPTER 6. CONDITIONS ASSESSMENT OF MITIGATION BANKING SITES . . . 36 6.1 GENERAL 36 6.2 BASELINE INFORMATION . . . . . . . 38 6.2.1 Hydrology of the Black River Drainage Basin . . . . . . 39 6.2.2 Land Use and Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 6.2.3 Water Quality and Sediment Erosion . . . . . . . . . . . . . . . . 41 6.2.4 Flood Conditions 42 6.2.5 Results of Review of Baseline Information and Field Assessment . 44 6.3 SUMMARY OF MITIGATION BANKING SITE INFORMATION . 49 6.3.1 Mitigation Banking Site 1 . . . . . . 49 6.3.2 Mitigation Banking Site 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 6.3.3 Opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 6.3.4 Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Parametrix, Inc. ii City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.p1n 6.4 ACREAGE AND TYPE OF MITIGATION FEASIBLE FOR THE MITIGATION BANKING SITES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 6.4.1 Acreage of Mitigation Feasible on the Mitigation Banking Sites . . 63 6.4.2 Type of Mitigation Feasible for the Mitigation Banking Sites . . . . 64 6.5 WETLAND ACREAGE POTENTIALLY ELIGIBLE WITHIN THE BLACK RIVER DRAINAGE BASIN FOR USE AT THE MITIGATION BANKING SITES 67 6.6 FEASIBILITY OF MITIGATION BANKING PROGRAM . . . . . . . . . . 68 6.6.1 Advantages of Mitigation Banking . . . . . . . . . . . . . . . . . . . . . . 70 6.6.2 Disadvantages of Mitigation Banking Program . . . . . . . . . . . . . . 72 CHAPTER 7. PUBLIC INVOLVEMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 CHAPTER 8. PROGRAMMATIC MITIGATION PLAN . . . . . . . . . . . . . . . . . . . . . . 75 CHAPTER 9. TECHNICAL MITIGATION PLAN . . . . . . . . . . . . . . . . . . . . . . . . . . 76 REFERENCES GLOSSARY APPENDICES A CITY OF RENTON WETLAND MANAGEMENT ORDINANCE B PHOTOGRAPHS OF SOIL TEST LOCATIONS ON MITIGATION BANKING SITE 2 _ ER F O P If AjNET , INC. TO THE TY II�.ENTIF D 0 INF TIO NEEDS E N TIQkT N ITEI 1 1 � ? D ATTENDANCE LIST AND HAND OUTS Fo Or,PUBLIC INVOLVEMENT MEETINGS E IJ,� OF OCAL,ETA ED�GENCY SENTATIVES INVITED TCCEEETIIVG »�.�✓-rY'S' �w.. ���cq�, ��-��� anJ�► ffD�J�n�. �G�c �' .£ ��'r. ,� �" ✓holes /n���rr�r 7� N� w,�a cry � /N►��' -Aix T-xAtj w/4a wt C,wTj► �? h',,f- /JiO 'Itlar, Acr,, Parametriz, Inc. iii City of Renton -DRAFT 55-1779-07 November 11, 1993 d,ftmtig ptn Con s .Ns ��a.df �� rfovi /^I A ueah 2 Sd�4� JCTION r � �CHAPTER 1. INTRODU '"" ` /z 4 �/4nLc artt< ek M Soh. �b,.�;1•t /Yltwc�p„r,e�,f' G cd=. The City of Renton is developing a wetland mitigation banking program and plan that is consistent with the City's Wetland Management Ordinance (Ordinance Number 4346) (City of Renton 1992) and Cc�mpr! ens'ye Plan (City of Renton 1993a). The mitigation banking program is a means to �'y' e policy of no net loss of wetland resources in a manner that optimizes a ecological benefits whileA ing.-the cost-effectiveness of compensatory mirlgtiThe wetland mitigation banking program will use lar er off-site areas to miti a e g a number of independent wetland development conversions. The basic concept involves a developer purcliasirig` wetland mitigation banking credits" from the City which has "banked" Zthem for this purpose. The concept of developing a mitigation banking program resulted from three primary actions: (1) the City undertaking an inventory of its wetlands, (2) the City developing and adopting a critical areas ordinance for wetlands (City of Renton 1992) pursuant to the Growth Management Act and, (3) discussions between the City and Glacier Park, a private landholder in the Valley, on the concept of mitigation banking. �o During the wetlands inventory, the City found that a number of high-value wetlands were still located within the Black River Drainage Basin ,e; Cram Uv;er-Valley (herein re€erred4e There were also numerous lower quality wetlands that potentially reduced`-"' property owners' property values. Figure, 1 shows tie extent�of inven oried wetlands and str ams ` -the Black River Drainage Basil � r tom, ` `'�' �� wdL;"4 g die presen eof bot� l -g�ower qua ityw°etfarAdsis the direct result of historic activiti KaA e Vapey. �. � e1tee. Originally, the Green River Valleygwasoc�,plai with i'e gh-value wetlands. Figure 2 shows the extent of natural wetlands prior toff e `men in th Valley ' 1972. During the rt� o=r w,1 fan r3, H"t,cyl/Ycr 1960s and 1970s, draining and filling activities rnustrra TA development resulted in cumulative losses of wetlands withinMaidley. Figure 3 shows the extent of filling from 1975 to 1987. Although many of the filled areas were developed, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These- depressional areas developed a perched water level (water that sits on an elevated area) and eventually developed into small lower quality wetlands. Many of these undeveloped parcels were owned by Glacier Park Company, a subsidiary of Burlington Northern Railroad. Aaa 11 r�.uling Hhongh the City es an ord.�' ance or the r tection and management not wetland 6ro.v - �p- resources in 1992 it as also c ncerne�'"wi"' s �` '� m ►y�'�` ee onomic base€ndZ cTArial lands y� cs, Concurrently urfn n northern `''c ecidegei o divest some properties held by the Glacier Park Company, a subsidiary to BN. BN also wanted to improve lhg.,market value of some of its is e r-Valley properties., Renton City Council passed a Wetlands Ordinaa e (City of Renton 1992) which provided opportunities to establish a wetland mitigation bank. Properties within the Valley that met certain criteria could establish and/or use an existing mitigation banking program, as long as the result was no net loss of wetland After meeting with the City Gt,Tea,-, 0 / Parametrlx, nc. I Vq lk et ua+� ity of Renton - DRAFT 55-1779-07 '!kv� j t November 11, 1993 drftmag.pin also SO yahrr f, s Oh Q Sj,�e ~ TALBOT AD S U A�9p�. O riP A � SHATTUCK Z aos WETLAND IQ� PANTHER CREEK t9 / apdN�Ea Pv N t 6 SF{.16T "�' 16 f rrrrrrrrrrrr SHOPPING CENTER t: J '7>> P P N 405 2 H .41 :V3 so .......................... M .rn. d• ...::::::.;::::........... ,. :f S O L IND AV S co V SW 1. L IND A W H 0 I- N / k O f f a z 3 a / w Y LL -- ---' p �.; --- - : �; :� A' 1 c: U m. / / / / / / / 1 ,F / / i/ / t< - �caE y - O}1KESD•AL•E:AV:$LU: %K / /"o E / a I GgP Pf1 / x 'SPRIP� ` 10 i a: m LONGACRES l �2 RACE TRACK \ CL JACKSON SW RENTON CITY LIMITS / ;MILL CREEK `\ BLACK RIVER PUMP STATION TUKWILA FOREBAY Figure 3. Approximate Extent of Filling / cq in the Valley hvm**W-ta-i �1�E✓f of Flu a�G r� iGp BLACK Fill Permits and Stop Work RIVER �'9 \ Source: R,1N`Beek and 8 social 1991 it s n o PUMP STATION E rie Fi remit TO GRE RIVER SCALE IN FEET A' i '�1 Areas Filled After 1975 0 Soo 1,000 Areas Filled Before 1975 i s Tq�eOTR TALEO7 Rp S � SHATTUCK aos � 3� r " " " " " AiJ8"" """""""""""""" Pp\N\��Pv N " " " " " " " " " " " 167 SHOPPING �� CENTER �. -A A aos = " "" M" % % ""cd ""tx " lkd " A"�'" " . "h" " " " "�" .1 p ��� S� �: "" LIND AV S "" "" :_, " ""s" a = i k W ij7��2t - LL " " ; O " " " " " S ." " " " e i " \9�s OAKESDALE AV SW j NNERE % " " " " " " " " " " " \• \ " " " " " " \ 1� " ova Ea \ ; m " � - 'CL JACKSON SW J' RENTON CITY LIMITS ---�._�-�... " % —��•• ///iiiii�iiiiiiiiii�iiiiifiiiii�ii��i�.�ri�iirii����iiiiiiiiisifiiiiiiiiiiiiiii�iiiiiiiiiiiiiii����iiiiiiiiiiii�iiiiiiiiiiiiiiiiii�siii�iiriiiiiiiii�ii��iii% ,MILL CREEK BLACK RIVER TUKWILA PUMP STATION FOREBAY / Figure 2. rn 147'-- �z �V _Natural WetlandsRrior to Valley Developmen FIa- BLAC K q z /5 BA U RIVER Source. R.W. Beck and Associates 1991 PUMP STATION U Ll)�ftLA r TO G EE DUWAMIS R N- u IY SCA LE FEET IN F T �' R ' RIV•' E N 1 0 500 1,0 00 >: �, t x lY, to dscft5s mitigation banking, Glacier Park onated to the City two large parcels that contained larger wetlands. In exchange, the City allowed Glacier'" Park to make some smaller parcels c nta'ning lower quality Caogery wetlands more saleable by weal ion six different parcel/� represeatmg p a to '"7"e`7 '' /SJL)C FP�"n fT -r-1 i, u '�041 of 5,33 r Crc f J- t.H41j3. 1 Y! The City-:mod two sites"f6taliag44 8.0 Thgse sites are to be used for compensatory wetland mitigation f^r tha c.33 am@- ^f file alinwed4 c c�l parcels stffl oN'o6," under Glacier Park ownership and for mitigation banking by other developments odwt- n -Glacier Parks irt-dm Val}cy to offset losses tq lower quality wetlands`/`'�'/'` "^� fr,w,t` Thcx-Ve��ff 1l alled Mitigation Banking Site 1 and Mitigation Banking Site aFe4town-m A,4,,� I,w�w•r F4gnr -* Mitigation Banking Site 1 is located north of Southwest Street, south of the42-4-4rk S. �1 �t owned by the-city of Renter, east of the Burlin nlorthern Rail Road, and west of Oaksdale Avenue Southwest c 25, ��23N, R 4E) - ). The site is 30.97 -S�'0 W �Q""''' acres and iA`Z"01 ied industrial is��so��ei dky developed land zone for cormnereia xd °n/ Fr6 y? industrial development along the southern boundary. n�eveloped commercial .ol" and industrially zoned land is adjacent to the western half of the southern boundary and to the eastern and western boundarie (Davi Evans and Associates 1997 a�; The site consists primarily Qr o� of revegetated fill material, place approximately 20 years ago, along with 12.19 acres of� "� ' '�q ��� relatively wetlands. disturbed upland meadow and shrubland and 18.78 acres of young forested and shrub � S i�Aj f A/'Yw. �!t/'� y,�h? 0vR� Mitigation Bankingrite 2 is located south of Southwest 34th Street, west of Springbrook Creg} , north of Southwest 39th Street, and east of Oak�jlale Avenue Southwest (Sec , T 23N, R ftE) (see Figure 4). The site is approximately 13.93 acres and consists of 7.16 acres of upland meadow and 6.77 acres of emergent, young shrub and forested wetland (David Evans and Associates 1991 b)' 'The site was filled over the past 20 years; the topography is relatively flat with small depressional areas. It is bordered to the north by undeveloped industrial and commercially zoned land. kFV'Sf F'G(t NLW Ie"014. XGAY k A00 ^^AP 00 rji , N. �a f< o�'•���� 6¢t• C,•ty A��rruy5 cs�ccl Once the City acquired the two mitigation banking sites it asembled an interdepartmental team consisting ofjr'eeresentatives from Surface Water Utili ,tey Planning, and Pazks and Recreation to manage and develop a mitigation banking plan (City of Renton 1993b). Once the plan is finalized and approved by the City, the City will implement the plan and mitigation program. The City intends to operate, maintain, and monitor the mitigation banking sites. w 4c) 0,11 Ain �'.; fr f.�✓-,( of ' Filling ofAese wetlands was permitted by the U.S. Army Corps of Engin/e�ers underllpi� ation id 26 permit process/ /e�/�Stv")� tn��( o� /�� wcreS. any ac1�1�I/Aw�� �.�ri��irNw�r^W� � �GIrS t -&0-4 by Yk C rff H�tr P"tie �n.l,v ��*� �eii+++r—prett4r. /Alb rl;CA4"- ' h..,re beep Parametrix, Inc. / S City of Renton - DRAFT 55-1779-07 ' � t0 "��' November 11, 1993 dr tmti I rc�,�� ll r�M)0, f S•Pn I � Tq� TALEtpT RD S Q� eOT V s � Ro �Z SHATTUCK aoUs EK WETLAND IQQ� r ra a � PANTHER CRE apdN�Ep�P� In z� 167 + SR-167 SHOPPING CENTER J U) t~n �2 n F- cD N N c�}} 2 (n / 3 U) U) Cl M C / V (� %/ cm � a LIND AV S � U co LIN AV SW Q k a u' w (� ) Y _ � \ LL / A i OAKESDALE AV SW z [: . / / Gg�p Eel z i:.::::.:::::..:,:.. :::.::<.; i \ 5P lP z w C: 10 o~ \ I LONGACRES a N [ j a: RACETRACK :::::::......::::: : tCL cn JACKSON SW ;: ` RENTON CITY LIMITS MILL CREEK \ BLACK RIVER PUMP STATION TUKWILA FOREBAY \ ; � Figure 4. Mitigation Banking fa 1:�5+ cq Sites 1 and 2XX , BLACK /'"(�-Lr'y(y)li`j� ,gyp RIVER ` Source: R.W. Beck and Associates ss dates 199 1 PUMP - l C Yr' i STATION TO GREEN- W DU AMISF'f' SCALE N FEET I F _ ,1 RIVER N 0 500 000 ......................... ..........................................................................................................................�i'.''I rC1i 5 rcc ..................... ............................................ city of 6 P-Channel Easement Renton >> 3, 4, s 5priNt rook Creck 2 M ITIGATIO N BAN K 51TE 1 EGmD 5.W.N tit_5treet Developable y • --�.: . Parccl Total Wetland Upland '0�::::4 Cz� r 9 8 l EGEhD 2 9.35 1.47 7.88 g W t� �, PARCELS FOR 5ALf 09 6 7.17 1.07 6.10 O ' ?' 6 6.86 0.22 6.64 ,'—'-'•V,;. 8W' 6.05 1.65 3.4U Developable Total Purchase � L�� : Panel Acres Pace J, 8E" 5.45 0.24 5.21 � 9 4.79 0.68 4.11 farce11 Z5 �3,1,1,72Q Towle 37.67 6.33 32.34 'tot 3 Parcels I lt.�I "north V2 J' Mitigation Total Wctland Upland MITIGATION BANK 51TE 2 Parcel 1t6.5 $100,MO Arta / 13 Parcc114 30.97 18.78 12.19 Parcel BW Totals 05.9 �gyc1 120 (Lots 1,2) 13.93 CLW ?-W 6 Parccl 8E "1 7,LY ,. _ ..__._..._...__._.__._.__.---.--......._...__....._...................... ___.._.__.._. �1<a��u�u' l�znll•lk 1Lza11nid1161®ll�lalln�a S.W.4lst Street Towle 44.00 2605 19�'S �n�: ��.- ��, lLr�3 __..._..__._...__.._�___..._... (G,ulm�lc�1� �►'d�i1>o1i1��v 2�dI�11P' CHAPTER 2. GOAL, OBJECTIVES, AND POLICIES OF THE MITIGATION BANKING PROGRAM A primary goal, objectives to meet the goal, and policies that are guiding principles t� ' eyed to be prudent-and-advantageous to achieving--d=vi3Jectives-and-goal--of the mitigation banking program are presented below. 2.1 GOAL The go" the purpose toward which the mitigaden-banFing-program is directed—T-�-Ck -of Renton's_overall goal-is to�r'eate a wetland mitigation banking program that is consistent with the City's Wetland Management Ordinance (City of Renton 1992).and-Comprehensive Plan(City of Renton 1993a) G„NI U 4 4,) A i k5 f,j, y51„k. A /um.f. 2.2 OBJECTIVES or " New -�o .)se +hs $ail A vJ 145 11'Kw+,,,'�5ar^ J6h,+,tl ainJ' of Q�Jc�.f/ve j 4,4O �Aqf Objectives ave been d veloped -a�eve tolzlp_ this goal. The objectives, which are primarily taken from the City of Renton's Comprehensive Plan (City of Renton 1993a) and Wetland Management Ordinance (City of Renton 1992; Section 4, Chapter 32, Renton City Codes), are listed below: • Encourage community development patterns and site planning that maintain and enhance natural systems, forms, and open spaces (EN-2.0, Comprehensive Plan). ImDliclt in this (-a0, b`4"8bjective is the need to define eligibility requirements for use.of the mitigation banking +.Q, sites and to provide a 1:1 acreage replacement on the mitigation banking sites for the 5.,33 y:,18 acres of impact to_Cateory 3 wetlands, f �p� �fw` VAT.,k _Rent Park. _ �1ti- N&_ Balance community desires for economic development with the responsibility to retain the City's wetlands base and protect environmental resources. -3L -r•� A'T60 a+4 C401 u61 �„Q,,/ p 3 Protect and enhance water quality of surface water resources (EN-4.0, Comprehensive Lee, � LPN``' Plan). Zt Q Provide for, and work toward, a regional approach to storm water management programs (EN-10.0, Comprehensive Plan). • Protect and enhance the City's rivers, major and minor creeks and intermittent stream courses (EN-5.0, Comprehensive Plan). OVA ✓f kria,,5 O� fop G PAf#S 3r �t ((ACE r ) ArMO 31 o5..y,a S ,a Parametrix, Inc. / o � o v5-7 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Pai or(go a.e.J Strive +4 •/� Increase surface storage capacity to decrease surface and flood runoff and increas groundwater recharge to maintain stream base flow. COf-32.- !.A (z Gay uif*,-4 o MtT 1CGt��P f1f; ��,I�C/hLv"rL • Protect the natural functions of 100-year flood plains and floodways (EN-7.0, Comprehensive Plan). • Preserve and protect wetlands for overall system functioning (EN-6.0, Comprehensive Plan). • P�d�&to- -9-wetland=so n�t[u�ai-features �- �z-- f j 1�,,+.r v+ C} F G-+�i�rr"� 4 n eP .5 t1 r ve Fir •► +�e/ yy,.. a,.er- �nrse yr-c. ,�i eA I • Consolidate wetland mitigation onto the Mitigation Banking Site. t /1'Jitf • Protect and enhance wildlife habitat (EN-14.0, Comprehensive Plan). • Support and sustain educational, informational, and public involvement programs in the City over the long term to optimize the use, preservation, and protection of Renton's water resources (EN-11.0, Comprehensive Plan). 2.3 POLICIES Policies are guiding principles that are considered to be prudent and advantageous to achieving the objectives and goal of the mitigation banking program; policies are presented below. N • Manage water resources for multiple uses including recreation, fish and wildlife, flood protection, erosion control, water supply, energy production, and open space (EN-4.1, Comprehensive Plan). • Design new development or land modifications within the 100-year flood plains to maintain natural flood storage functions and minimize hazards (EN 7.4, Comprehensive Plan). • Preserve natural surface water storage sites that help regulate surface flows and recharge groundwater (EN-8.2, Comprehensive Plan). • Utilize, maintain, and enhance the natural storm water storage capacity provided in existing significant wetlands (EN-8.10, Comprehensive Plan). • Manage cumulative effects of storm water through a combination of engineering and preservation of natural systems (EN-9.4, comprehensive Plan). • Achieve no net loss of the City's remaining wetlands (EN-6.1, Comprehensive Plan). APO Pa L 1 <4t5- C6—7,3 Parametrbx Inc. 8 % City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin S T141S C-14APFCA -P-JouL0 56 A(3t4 7o p rks CHAPTER 4. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION Ar0 o7VU s A-5 BANKING SITES �Aw * )NF+t AT160 &9 0V In general, eligibility criteria for use of the mitigation banking program are based o e lato rec�uireme s,and ecological consideration The eligibility criteria for the City's program would determine which wet?aa`Rg c'Ic"lbver Drainage Basin may be altered and subsequently q Y compensated for at a mitigation banking site. A draft list of eligibility criteria and standards for the eligibility criteria are presented below. This list of eligibility criteria and associated standards will be used by project proponents and the City to determine whether impacts to wetlands may be compensated for at the mitigation banking sites. Meeting the standards of each criteria will be necessary before the City's mitigation banking program could be used. A simplified flow chart of the eligibility criteria is shown in Figure 5. This can be used in conjunction with the standards to determine whether mitigation banking should be considered. 4.1 ELIGIBILITY CRITERIA 1: Does the Proposed Project Comply With the City Wetland Management Ordinance (Ordinance Number 4346)? Standard Projects that have unavoidable and necessary impacts would be considered for incorporation in the wetland mitigation banking program,provided that they demonstrate compliance with all other standards of the City's ordinance. For example, use of the mitigation bank to compensate for wetland impacts would be tied to the mitigation policy of sequential mitigation actions including avoiding adverse impacts, taking affirmative measures to minimize impacts, and compensation for impacts.6 Mitigation banking is basically a form of compensatory mitigation. In addition, the mitigation should be comprised of the same or higher category habitat than the altered habitat, so that similar or greater functions and values in the drainage basin are achieved [see Section 4- 32-6 (A)(2) of the Wetland Management Ordinance], and the City's standards for wetland creation and/or restoration are met. 2• APP2o��0 O(tV/NfaTjo►� ft�n.. �RPS�G/T�1 CIJQ.N% , FUuJ,n►r o` oN E 7��hT. A P-1^crS ^R6 UNf+��►��dtE �♦ �7 / I'� TN�iS� !rJ'P�S �t+✓9 ASiSt:E R PRkVA1-S o f 774 f e This standard may need to be revised based on decisions regarding some of the policy issues in Chapter 3. Parametrix, Inc. 28 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag.pin Eligibility Criteria 1: MITIGATION BANKING No DOES THE PROJECT COMPLY WITH THE SOULD NOT BE CITY WETLAND MANAGEMENT ORDINANCE CONSIDERED (ORDINANCE NUMBER 4346)? Yes No Eligibility Criteria 2: IS THE PROPOSED PROJECT LOCATED WITHIN THEABLACK RIVER DRAINAGE BASIN ? b Yes �ol�c/i �uzna 1'9�r Eligibility Criteria 3: UM K � �w�c No IS THE IMPACTED WETLAND �H7 Lin, LESS THAN ONE ACRE,AND ISOLATED �Efutey OR ABOVE THE HEADWATERS? /' nTv i Yes Yes Eligibility Criteria 3: IS ON-SITE MITIGATION FEASIBLE?�P��174cu �C�Wr1unm�nX�y� tC.oYurw `d'uY I No ELIGIBLE FOR MITIGATION BANKING PROGRAM Figure 5. Flow Chart to Determine Eligibility for Use of Mitigation Banking Program _iii15 11 A"(—P4gOI PA1'* ^(- 'rL6 OW)N^,JCE 4.2 ELIGIBILITY CRITERIA 2: Is the Proposed Project Located Within the Black River Drainage Basin? Standard Gl Ut F-�or The altered wetland must be located within tQlack River Drainage Basin, including the Green River Valley. 4.3 ELIGIBILITY CRITERIA 3: What is the Size and Category of the Wetland That May be Affected? /�Qr-�N /vAt-(,q To Standard' ! DIACaRRw Wetlands classified as Category 1, 2, or 3 by the City that may be altered consistent with the Wetland Management Ordinance (Ordinance Number 4346) are potentially eligible to use the mitigation banking sites. Written documentation from the Corps on the jurisdictional status(e.g., isolated, above the headwaters, less than 1 acre) of the wetland to be altered would be required. For sites with wetlands that are less than 1 acre and above the headwaters but do not have specific project plans, a copy of the jurisdictional letter from the Corps would need to be submitted to the City. For sites with wetlands that total less than 1 acre, are above the headwaters, and have specific project plans, a copy of the Nationwide Permit would need to be submitted to the City. Impacts to wetlands that require an individual permit (Section 404) from the Corps and/or Ecology (e.g.,Nationwide 26 for impacts to wetlands between 1 and 2 acres that are above the headwaters) may also be compensated for at the mitigation banking sites. A developer would need to provide the City with a copy of the appropriate permit along with written documentation that the state and federal agencies concur on using the mitigation banking sites for compensatory mitigation. 4.4 ELIGIBILITY CRITERIA 4: Is On-site Mitigation Feasible? Standard �A4 �Jo ES �l9!S (ern P r 4�, 00-sl�E VS• Uf-F�SiT� ?a G(�QS �(�2.�� hi(� S1.L.F�_ � r The wetland to be altered would be considered eligible for use of the mitigation banking program when: • The hydrology and ecosystem of the original wetland and those adjacent lands and/or wetlands which benefit from the hydrology and ecosystem will not be substantially damaged by the on-site loss; and 7 This standard may need to be revised based on decisions regarding some of the policy issues in Chapter 3. Parametrix, Inc. 30 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin • On-site mitigation is not feasible (due to problems with hydrology, topography, soils, location or surroundings of the subject property, surrounding land uses); or • On-site compensation is not practical due to potentially adverse impacts from surrounding land uses; or • Existing functional values at the proposed mitigation banking site are significantly greater than lost l wetand functional •unctona values or J 11 � r1� P.n V 1/on vh P,r�a I h�''n���� �y,r • Established regional g s oI'flood storage, flood conveyance, habitat, or other wetland function have been addressed and strongly justify location of compensatory measures at the mitigation banking sites (City of Renton 1992). Parametrix, Inc. 31 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtigpin CHAPTER 5. REGULATORY REQUIREMENTS TO IMPLEMENT THE MITIGATION BANKING PROGRAM Any work necessary to restore the uplands on the mitigation banking sites—involving any in- water work, alteration of existing wetlands, grading and filling—is potentially subject to regulations implemented by federal and state regulatory agencies and the City of Renton. The types of federal permits associated with altering the on-site wetlands that may be needed will be dependent on two primary factors: 1. Whether the City chooses to excavate any of the existing on-site wetlands (e.g., reed canarygrass wetland vegetation adjacent to Springbrook Creek) as part of the effort to restore the functions and ecological communities to the site. 2. The jurisdictional determination on the wetlands within the mitigation banking sites being completed by the Corps. Currently, the site plans being developed for the mitigation banking sites do not include altering the existing wetlands. There are two reasons for maintaining the existing on-site wetlands: (1) the City of Renton's Wetland Ordinance does not currently recognize enhancement of wetlands as a form of compensatory mitigation, and (2) a Corps permit (e.g., Nationwide 26 or 27, or an individual permit) would be necessary to undertake excavation activities within the wetlands. If the Corps determines that the wetlands within the mitigation banking sites are "adjacent," and the City chooses at some future date to excavate lower quality portions of the existing wetlands, a Section 404 Individual Permit would be required. Alternatively, if the Corps determines that one or both mitigation banking sites are above the headwaters, and the City chooses at some future date to excavate lower quality portions of the existing wetlands on the mitigation banking site(s) (i.e., less than 1 acre, or between 1 and 2 acres), Nationwide Permits 26 and/or 27 would be required. In addition to the permits associated with restoring wetland communities on the mitigation banking sites, the City would also need to initiate discussions with the King County Drainage District to ' ti.-- -'- �'- reestablishing a hydrological connection with Mitigation Banking Site 2 PC 711[/ 1\ITP of nPrmit �i�llin.i� tfe /Iccen.rr 4///av^1s a.) fefa,.eel f6 The federal, state, and local permits that may be needed by the City of Renton to undertake construction activities to restore the upland sections of the mitigation banking sites to wetlands are identified in Table 3. Parametrix, Inc. 32 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmag.pin Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" Water Right Permit and Certification Required for removing Ecology, Northwest Ch. 90.03; State Currently averaging 2 Permit normally good any water from waters Regional Office. water to 3 years. City may for 5 years. After I t of the state, including code—surface already have a water water is used, water for non- water right permit to certificate is obtained consumptive purposes. Springbrook Creek, in which is good in 'S which case the city will perpetuity. need to obtain a change-in-use permit. Local Shoreline Substantial Required for any City of Renton City Shoreline Permit is usually Shoreline permits are Development Permit substantial development Master Program obtained in 4-6 months. valid for 2 years. within 200 ft of a RCC 4-19 Extensions are shoreline area.. possible. Sensitive Area City g0ps)YdlGg�d A ity of Renton RCC 4-32 Process occurs upon Valid for 2 years. Regulation th ugh sensl{rve 11- submittal of any Extensions are rdinance. building or land use possible. permit review and/or to obtain approval of use and/or development of land. Fill and Grade Permit Must be issued prior to City of Renton RCC 4-10 Grading permits for Grading must begin start of construction. projects are generally within 6 months of Does not permit issued within 4-6 permit issuance; physical construction. months. grading permit is valid See Construction for the duration of Permit. construction. Construction Permit Must be issued to start City of Renton City design Timing varies Valid from 1 year and Grading License construction. Issuance standards and depending upon from date of issuance. follows final review of codes completeness of plans. construction plan drawing and other City of Renton permits. Site Plan Approval Ensures proposed site City of Renton RCC 4-31-33 Generally 4 to 6 Good for 2 years with plan complies with City months. a 2-year extension. code and surrounding uses. Land Clearing and A land clearing and/or City of Renton RCC 4-9 Permits for land Valid 1 year from date Tree Cutting Permit tree cutting plan is clearing and tree cutting of issuance. reviewed as part of the are generally issued SEPA review and within 1 week. permitting process. Parametrix, Inc. 35 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin CHAPTER 6. CONDITIONS ASSESSMENT OF MITIGATION BANKING SITES 6.1 GENERAL The Black River Drainage Basin encompasses approximately 24 square miles and includes the cities of Renton, Kent, Tukwila, and portions of unincorporated King County (Figure 6) (R.W. Beck and Associates 1991). The basin extends from the confluence of the Black and Green rivers at Tukwila, south along the east side of the Green River to the City of Kent and east to the BSc R�pf�cr�, western edge of the King County. see e The valley floor within the Ci o -Menton has numerous Wetlands and has experienced recurrent flooding and water qua1. _;issues development of the Valley has occurred f ars. The natal drainage patter§in the Valley is primarily influenced by the Springbrook Creek/Black River system. Mill Creek in K-eftt; Garrison Creek rree , Panther Creek-iR R4ntea-imd-*ing--Couaty, Rolling Hills Creek- and Watershed in are the primary tributaries to Springbrook Creek (R.W. Bepk and far Associates 1991). These streams originate east of the Valley ancfWsupple&ne ted by roc z4e"d inflo�Within the Valley. Historically wetlands covered most of the Valley. These wetlands were considered to be part of the same ecosystem (see Figure 2). Within the last 20 years extensive filling and development have resulted in a loss to the wetland resource base and have fragmented the existing wetland ecosystem (see Figure 3). Numerous smaller wetlands still exist within the Valley despite the historic wetland loss. Many of the remaining wetlands are considered to be lower quality (primarily Category 3 wetlands) and provide minimal wetland functions. The ;Fhei.?s� rq wetlands (Category 1) are owned by the City of Renton and are associated vv� S rmgbrooYA wgjI Creek s ee Figure 4) The City recently acquired two additional parcels of land associated with r,l6 y t Sprmgbrook_Creek that contain both uplands and wetlands (see Figure 4). The City acquired the Vlejjs parcels with the intent of restoring wetlands within the upland areas to provide a mitigation banking program to help offset wetland losses due to development.A site visit was made to the mitigation banking sites on August 3, 1993 to evaluate the feasibility of restoring wetlands and establishing larger, high-quality wetlands for the mitigation banking program. The purpose of the on-site investigation was to assess the current physical and biological conditions and to identify opportunities and constraints associated with establishing these sites as mitigation banks. The City provided a field crew from the Department of Public Works and a backhoe to determine the depth of fill and to evaluate the soil characteristics. Observations of the soils,plant communities,and existing hydrology were recorded. Observations were also made of potential opportunities to use water from the existing ditches along the western boundary of Mitigation Banking Site 1, and to redirect a portion of Springbrook Creek through Mitigation Banking Site 2 to serve as a source of hydrology for newly established wetlands. Parametrix, Inc. 36 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin CITY OF TUKWILA , GREEN RIVER WILL CREEK i- v' i i I I Valley Subbasin C CITY OF i KENT i 1 r. L.J Springbrook l i ••• Springs L.J Subbasin #•� .� �._. .-._._.-._.-._.-._., �•••••�____- •�•. `..........� Rolling Hills % Subbasin ,c Panther Creek cREE PANtNt:R Subbasin i i i i i i i ' PANTHER LAKE ' Can As'irA� In F16UP4 Foy. City Limit Boundary DRAFT FIGURE 6 nr t4 &Asw ■ BlackSubb fiver Basiundn Boundary SOURCES: JONES AND STOKES, 1991 BLACK RIVER DRAINAGE BASIN 0 �00000 P Parametrix Inc ry CITY Or RENTON,JONES AND S.19913993 SCALE IN FEET c:+j!,j 7k re�crecc fh 1s r"t,/+ In addition to the site visit, existing informatiowwas reviewed on the Black River Drainage 5� Basin,the two proposed mitigation banking sites, and surrounding wetlands. is ing in o n Vl inGlude&the 41owing David Evans and Associates (1991 a,b) u The East Side Green River Watershed Plan (R.W. Beck and Associates 1991) • Black River Drainage Basin Water Quality Management Plan (R.W. Beck and Associates 1993) , , • Level II Environmental Assessment, South Part of Parcel 13, Glacier Park Company (Golder Associates, Inc. 1992) • Preliminary Environmental Assessment GPC Property Sequence No. 968, Parcels 13 and 14, Renton, Washington. (Hart Crowser, Inc. 1991 a) I , f Preliminary Environmental Assessment Orillia Corporate Park Property (Sequence 850), Renton, Washington. (Kennedy/Jenks/Chilton Consulting Engineers 1989) • Preliminary Surface Water and Sediment Quality Assessment; Springbrook Creek- Orillia Industrial Park, Renton, Washington. (Hart Crowser, Inc. 1991 b) t City of Tukwila Southeast Central Business District Drainage Study. (Gardner Consultants, Inc. 1992) Final Environmental Impact Statement, City of Renton Comprehensive Park, Recreation and Open Space Master Plan and Trails Master Plan. (J.C. Draggoo & Associates and Osprey Environmental Services 1991) 6.2 BASELINE INFORMATION /s Nor Yk-ob � r The mitigation banking sites occur within the Valley subbasin, a,,i§ubbasin to the Black River wr' ANc Drainage Basin (see Figure 6). Mitigation Banking Site 1 is S to the i-by rselat�irvely high-quality Category 1 wetlands owned by the Cite Fie gure 4 To the west it is bound by �s� eti a ditch and- astures to the south by commercial development, and to the east by O s e 6Ma1Nt,1 Avenue SW and-additiend Cate l-wetlands-ovmed by-the-may. Mitigation Banking Site 2 n-'O'A is bound to the north by prope ermitte for development, to the east by Springbrook Creek, and to the west by Oalodale Avenu SW and_Spfin ro9k C+`ek-(see Figure 4). T✓GG�� Parametrix, Inc. 38 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Baseline information on features of the Black River Drainage Basin that is pertinent to the mitigation banking sites is followed by a summary of existing information for the two sites, and a discussion of opportunities and constraints associated with restoring the uplands portions of the mitigation banking sites to wetlands. �nrc-i- a 6.2.1 Hydrology of the Black River Drainage Basin SA5w pQptAj)nu4 � 7,01 5�csloa :AWL' Jf , R.utulm. to 1l tS • Springbrook Creek and Panther Creek are the two primary streams within the basin (Figure 7) (R.W. Beck and Associates 1993). Springbrook Creek flows north along the valley. The upper basin includes a large portion of the City of Kent, including Mill Creek. Major tributaries to Springbrook Creek outside of the basin include Mill Creek and Garrison Creek. The lower portion of Springbrook Creek, known as the P-1 channel, has been enlgred over the years to C.M le te con accommodate flood flows (R.W. Beck and Associates 1993). ,� low Springbrook Creek can rat• range from an average minimum (low) flow of approximately 4,5cfs to a peak flow of approximately 900 cfs during severe flood events. Sprin gbrook Creek toms the Black River at the Black River Pump Station and is considered to be a small remnant of the old Black River that drained Lake Washington before the Lake Washington Ship Canal and Ballard Locks were constructed by the Corps in the 1920s. The pump station transfers water from the Black River to the Green River. Upstream from Southwest Grady Way, Springbrook Creek has been deepened and widened in past years by farmers, locals, and the King County Drainage District No. 1. 61^ �Wn trS Panther Creek is another drainage that affects the valley system (see Figure 7). The Panther Creek Wetland has two primary runoff sources, Panther Creek and the Rolling Hills Basin, , Panther Creek drains the upland plateau in the eastern portion of the basin. Panther Lake is located at the headwaters of Panther Creek (see Figure 1). Panther Creek enters a large wetland, the Panther Creek Wetland, which extends along the east side of the State Route 167 (SR-167). During large storm events, excess flow from Panther Creek enters the south end of the wetland. The culvert merges with a storm water drain on 34th Street, which eventually discharges into ' Springbrook Creek. Excess runoff from the Rolling Hills Basin also enters at the north end of the wetland during large storm events. Flows from the Rolling Hills Basin are connected to the enton Village Shopping Center conveyance system (R.W. Beck and Associates 1991) (see U' Fi6'I Figure 7 . e shopping center carries runoff to a culvert crossing underneath Interstate 405 (I- ; rh'S 405). From the I-405 crossing, a low flow channel carries runoff along the east side of SR-167 to a culvert that crosses west underneath SR-167; this culvert carries flow west and discharges into Springbrook Creek. 6.2.2 Land Use and Capacity /� 7l�is 1;y7�f,•T L.A�Ac�y n �� A .rrlcrP Tj69 r'P A� re W9'r'L Present and future land uses in the Panther reek and Springbrook Creek drainage basins have been described by R.W. Beck and Associates (1993) and were based on aerial photographs of the area from 1988 and 1989, area comprehensive management plans, and local zoning maps. Anticipated changes in the area of land zoned for a variety of uses is shown in Table 3. 6A5"Jes if� C'qsrbLt us"? Parametrix, Inc. 39 City of Renton - DRAFT 55-1779-07 GA-344A4 4ui- "AQ.•r C4.o 01 a"; November 11, 1993 drftmtig.pin TALBOT RD S 71 G s �Q a- SHATTUCK 3 PANTHER CREEK�JJETLAND QQ� PpJN�ER Pv N 167 36"67 SHOPPING 60" SR-1 36 36" CENTER cf) N N H Co F— Q (n U N v Cn v U) / 36" / LIND AV S 48 60" ao I co F LIND AV SW v N Cl) cV % W 21° r -- U LL ---- - — i 0 / U ' N cD �90U1 Cl) �`k" N 60" / /K I 60 y / Ga EK� OAKESDALE AV SW j i J < 00 NEVI \ 3 SP 6" j P� LONGACRES CY) % I� RACETRACK % Z JACKSON SW _l J% RENTON CITY LIMITS % 1, MILL CREEK \ BLACK RIVER 1 PUMP STATION TUKWILA \ FOREBAY Figure 7. Valley Drainage Patterns BLACK RIVER F,9 PUMP \ Source: R.W. Beck and Associates 1991 -1b 1`��V f PON t STATION TO GREEN-DUWAMISW 36 36"Diameter Storm Drain 1 RIVER SCALE IN FEET — — N Stream/Drainage Channel 0 soo 1,000 )--( Culvert(s) Table 4. Anticipated changes in land use in acres (R.W Beck and Associates 1993). tl Land Use Springbrook Creek Panther Creek Commercial +712.9 +8.2 Multi-family residential -14.0 +96.0 High-density residential +229.4 +347.7 l\ J` Medium-density residential +144.4 -62.4 ,`7`lS"X¢Qa Low-density residential -216.3 -91.20 Upland forest -56.3 -160.1 Upland cleared -183.1 -123.3 Lowland undeveloped -626.9 -12.3 Lake 0 -8.1 ,Qj� — indicates increase in land use for the particular zoning 4at ObWt 104S f0id indicates decrease in land use for the particular zoning d �a Table , indicates that the anticipated changes in land use in the Springbrook Creek Drainage N Basin will be toward more commercial and high- and medium-density residential housing. Commercial development currently predominates in the lowland areas in the western portion of the basin (i.e., Springbrook Creek Drainage Basin) and in the Renton commercial district. A large portion (approximately 1,510 acres) of the Springbrook Creek Drainage Basin is currently undeveloped; however, most of this area is expected to be converted to commercial and high- density residential development. Future development in the Springbrook Creek Drainage Basin will convert the existing undeveloped forest land and low-density residential areas to predominately commercial and high-density residential. The City of Renton estimates that commercial portions of the Springbrook Creek Drainage Basin will be completely developed within the next 5 to 7 years. Assuming that development occurs uniformly during this period, approximately 250 acres of land will be developed each year in the Springbrook Creek Drainage Basin (R.W. Beck and Associates 1993). Full build-out of the Panther Creek Drainage Basin is expected to occur at a lower rate estimated to be between 15 and 20 years. Thus, the amount of land developed each year in the Panther Creek Drainage Basin would be approximately 45 acres. 6.2.3 Water Quality and Sediment Erosion Sediment loading in the Black River Drainage Basin can deteriorate the water quality and affect aquatic organisms residing in the major streams and tributaries. The major sources of sediment loading in the basin are upland erosion in the watershed and in-stream channel erosion. Upland Parametrix, Inc. 41 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin erosion is caused primarily by land-clearing activities associated with construction and development (R.W. Beck and Associates 1993). The accumulation and subsequent runoff of street dust and litter during storm events also contributes to suspended solids in urban streams. In-stream channel erosion results from erosive actions of concentrated runoff (R.W. Beck and Associates 1993). Increases in peak flow rate and duration caused by urban development and major storm and flooding events can significantly affect channel stability and increase the amount of sediment transported by the stream, unless adequate storm water control features are constructed to reduce the rate of storm water runoff from developing areas. The areas of greatest concern within the basin are upper Panther Creek and upper Springbrook Creek where extensive development is predicted and where already unstable bank conditions would be aggravated by increased flows from future development (R.W. Beck and Associates 1993). Using the future �r,f development scenarios developed by R.W.Beck and Associates(1993),the total estimated erosion p��1 for Springbrook Creek is 42 tons per year without flood controls and 0.3 tons per year with flood 5"� controls (R.W. Beck and Associates 1993); for Panther Creek, estimated erosion is 104 tons per year without flood controls and 0.7 tons per year with flood controls. Most of the residential development has occurred and will continue to occur in the eastern portion 4 a 114 of the Panther Creek,//,,D�r, * age Basin. High- and low-density residential development is the 'trAt primary current land 4is . ' ost of the low-density residential and undeveloped forest lands are AP1(,6P14P'4 expected to be converted to high-density and multi-family development in the future. The existing water quality of Springbrook Creek is poor (R.W. Beck and Associates 1993). Factors contributing to the present water quality include low dissolved oxygen, high numbers of fecal coliform bacteria, and high levels of turbidity, conductivity, total phosphorus, solids,metals, and ammonia. R.W. Beck and Associates (1993) indicates that the existing water quality may be affected by past structural changes in Springbrook Creek.the reduction of pollutant removal C.S C wl n 4� fi , ,.�i, t, !""+ P ,� provided in wetlands, and an increase in pollutant sources. -t�redg�l the cry-owned wetlands, fix restored wetlands in Mitigation Banking Sites 1 and 2, and-in other :Wetlands within the basin are important steps for water quality improvement as each wetland may provide an important polishing function for the water and trap sediments, especially during high flows. 6.2.4 Flood Conditions The Renton area of the Valley has recurring flooding problems. A levee system constructed along much of the Green River in the 1950s, which included a flood gate at the confluence of the Black and Green rivers, allowed the Black River to flow into the Green River during low Green River flows. It prevented the Green River from flowing back into the Black River during periods of high Green River flows that would flood the Valley area (R.W. Beck and Associates 1991). This flood prevention mechanism was not effective because interior floodwaters could not be discharged from the Valley when the flood gate was closed due to high Green River flows. Parametrix, Inc. 42 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Vol During the 1960s the Soil Conservation Service (SCS) undertook a planning exercise to look for V 1 solutions to interior valley flooding problems. In addition, construction of the Howard Hanson Dam in 1962 helped prevent major valley flooding (provides an estimated 500 to 600 years of protection) from the Green River; however, it did not solve the interior valley flooding problems when Green River flows closed the flood gate for the Black River. In 1965, the SCS developed the East Side Green River Watershed Work Plan which recommended land treatment measures (e.g.,cropland management,wildlife preservation/enhancement)and structural measures(e.g.,new or improved drainage channels for collection and conveyance of runoff, discharge structures, such as pump stations, and improved outlet channels) to manage storm water runoff and to resolve the interior valley flooding (R.W. Beck and Associates 1991). The Black River Pump Station (BRPS) was completed in 1972. Its function is to lift the interior valley drainage so that it flows by gravity into the Green River. During the late 1970s and 1980s �� additional studies were completed on alternative flood storage and control,lneasures;these studies, led to the development of alternative channel alignments (i.e., enlarged"and realigned 11.1 miles \u''•1�vS, of stream channel to provide storage and convey flood waters to the BRPS), the creation of two �+` A flood storage ponds (i.e., construction of the BRPS forebay to provide flood storage when the BRPS has to restrict pumping rates during high Green River flows) and a reduction in channel size (i.e., reduction of the P-1 channel width within the City of Renton from 165 to 200 ft to 70 Uo 80 ft). Between 1984 and 1990 the City of Renton and the SCS undertook the construction of the BRPS forebay, the P-1 channel from the forebay to SW Grady Way, the Grady Way Box Culvert, the P-1 Channel East Side Retaining Wall, the 1-405 Box Culvert (not operational since no channel improvements have been made to allow Springbrook Creek to flow through the structure), and the SW 16th Bridge replacement. In add i „Yh ity undertook an evaluation for allowing construction of the P-1/P-9 Channels souZO O° r treet. This process resulted in the City determining that the final,SCS Environmental Impact Statement (EIS) could not be adopted without a nev EIS or supplemental EIS. Subsequently, the City retained R.W. Beck-and -Assoeiates associated consult4nts, to gather, and evaluate the technical and environmental information needed to supports a sups lemehtal EIS using two independent but coordinated planning efforts: the East Side Green River Watershed Plan (R.W. Beck and Associates 1991) and the Black River Drainage Basin Water Quality Management Plan(R.W. Beck and Associates 1993). Potential flood control alternatives presented in these plans include: • A no-action alternative (i.e., no flood control alternatives are implemented) • Localized improvements to Springbrook Creek combined with other Valley area drainage improvements to eliminate existing flooding problems in the Valley area • Establishing a ow diversion channel (SCS P-1 and P-9 Channel projects with modifications) and maintaining Springbrook Creek as a fisheries flow channel Parametric, Inc. ��a4l• `n 43 p City of Renton -DRAFT 55-1779-07 (���. P(,J J CH��dS /� L„ Cv November 11, 1993 drftmtigpin vc� uSkih��y�f tiut. Gu"J )n(0 1 S ti of lon.ws�L (horL G<IjGISJ/on iS �) f o, ju 6 s1-5 ilv' �A. • g st wa er o th en n e re r No formal decisions have been made about the flood control alternatives presented in the most recent plans prepared by R.W. Beck and Associates (1991;1993). 6.2.5 Results of Review of Baseline Information and Field Assessment .44 f/,4.VTOr" VLt' Surr✓Nd+M W4M 5" The results of the field assessment of the two mitigation banking sites indicate that both sites sys4 r,c . contain relatively low-value seasonally perched wetlands that are generally composed offer_* cottonwood,Populus balsamifera;red alder,Alnus rubra; salmonberry,Rubus spectabilis;willow, lorA Salix spp.; and reed canarygrass, Phalaris arundinaceae. The wildlife habitat value of the mitigation banking sites is limited by development adjacent to and near the properties; although the wildlife habitat value of the large wetland and its associated buffers on Mitigation Banking Site 1 appears to be greater than Mitigation Banking Site 2. Both sites support deciduous trees that are well developed but not fully mature. Consequently, opportunities for cavity-feeding and nesting birds, for example, are limited. The relatively young age of the forested portions of both sites and the relatively low species diversity within the plant communities limit the value of these sites for wildlife. In addition, there are few, if any, permanently wet areas on either site. The existing wetlands are seasonal in character and possess relatively low functional values for flood water abatement and storage, and water purification. The wetlands are also poorly developed and somewhat artificial (i.e., developed on pans in isolated depressions on top of fill), and occur at elevations 5�feet higher than neighboring water bodies (e.g., Springbrook Creek) Both sites have large areas in which reed canarygrass and introduced blackberry species (Rubus discolor procera, R. lacianatus) have become established. Mitigation Banking Site 1 also has areas in which Scot's broom (Cytisus scoparius) grows. These plant species will continue to expand their ranges unless shaded by taller vegetation,removed, or otherwise controlled Mitigation Banking Site 2 does not show evidence oifiuman ' rusior, but Mitigation Banking Site 1 is frequently used as a sport off-road vehicle area, an ac i ' at has resulted in significant disturbance to the landscape despite efforts by the City to restri entry for this purpose. Q Ic u.1k o„ + ar l.ncs ,d)o�r*I +► A significant amount of fill has been placed on both sites, and the depth of fill appears to be as ,f ? great as 10 ft in some places. This material generally has low organic content and relatively permeable sandy soil and, although soils in the wetland areas show signs of mottles, the soils may not have been hydric when deposited. Using a backhoe, three soil test locations were dug on Mitigation Banking Site 1 and five were dug on Mitigation Banking Site 2. The soil test locations are shown in Figures 8 and 9, and the results are presented in Figures 10 and 11. Photographs of the soil test locations are provided in Appendix B. Parametrix, Inc. 44 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 1 8. 18 W - 13C : 4 W _ 12 ' : : HIGH FLOW DIVERSION CHANNEL IMPROVEMENT 16 Upland ea o co munity WETLAND M: Young, forested, shrub, . .and emergent wetland communtity WETLAND M ..18 W - 22' i � ., .. •, : I '• • ' : . : , ' •" . ; '.: � . . . . . .. '• ." : •: : � of � /✓1 20 W 2CO WETLAND L: WETLAND J: — : Shrub community Shrub community Upland meadow and shrubland community man . W - 45 - _ _ SW 33rd W-22 = Wetland code from FIGURE 8 Parametrix, Inc. DRAFT Jones and Stokes, 1991 O 7 O — — = Mitigation site boundary EXISTING CONDITIONS SCALE IN FEET October 19, 1993 SOURCE: MITIGATION SITE 1 CITY OF RENTON, 1993 ® = Soil Test Pit Location (approximate) — --_.- o KS ALE AVENUE 717 ♦ . 17 17 - ,� � 7 I W - 32 ♦ W — 3 2 ♦ We meadow,: emerg:ont . ♦ wetland,. :and :.young - f reste viretla.n.d: : . . I . ... -W _ 14 . ♦ 2 Upland shrub and I W — 3 2 ♦ O meadow communit ��P ♦ Y I .. 1:6 g5� 8 16 �'�o ♦♦ W - 32 : �',p ♦♦ Young: .forested r*j cD 16 rr rr W - 32 W — 40 W-32 = Wetland code from FIGURE 9 Parametrix, Inc. DRAFT Jones and Stokes, 1991 0 75 150 0 — — = Mitigation site boundary EXISTING CONDITIONS SCALE IN FEET MITIGATION SITE 2 October 19, 1993 SOURCE: RENTON, 1993 = Soil Test Pit Location (approximate j SURFACE SURFACE SURFACE SURFACE SURFACE 1 ELEVATION 2 ELEVATION 3 ELEVATION 4 ELEVATION 5 ELEVATION SURFACE 19.5 16.5 16 15.5 16 777 -2 17.5 14.5 14 13.5 14 77 -4 — 15.5 12.5 12 11.5 12 6 13.5 10 5 w 10 9.5 10 w .:::::...:. ...:. w . .... z a w 11.5 8.5 0 8 8 7.5 8 ....... ......................... .. ...... :::.:::.::::::.:::::::::: I ! ! I ! ! ! -10 9.5 i\l\l`r`J`i`r 6.5 6 5.5 6 � l J ! ! ! ! J \ \ \ \ \ \ \ -12 7.5 4.5 4 3.5 " " " \ 4 • r r f ! / / i r r f r f \ \ \ \ \ \ \ \ \ \ \ \ \ -14 5.5 2.5 2 1.5 2 Sandy Silty Fill Seepage Silty Sand Fill with Mottles ® Concrete Figure 11. Fine Sand Clay \,%,%,%l Black Sand Soil Test Location Characteristics ® Iron Oxide Layer Sandy Silt/Silty Clay Historic A Horizon of Mitigation Banking Site 2 6.3 SUMMARY OF MITIGATION BANKING SITE INFORMATION 6.3.1 Mitigation Banking Site 1 WLM NW c4WEA 067f Mitigation Banking Site 1 is 30.97 acres and is within the 100-year Green River floodplain.oPw+n Fiu- Approxim�te17e-third of the site has been cleared, or cl ared and filled, over the past several uz years. I A 97 the site was cleared of all trees, and a,�dg°r t om"P"At ered through the site was filled in, creating localized wetlands (Hart Crowser 1991a).rrt/_\,,'0F/. 5�( ? Farming was the predominant �ctivity on the site until the early 1980s. Three wetland communities were identified ang delineated by David Evans and Associates(1991). The wetland ? communities typically occur in the r ,, areas and'trielmajority of upland ,.. wG� A,J+9Sr communities occur in elevated areas that have been more recently filled. The on-site wetlands are considered to be Category 3 wetlands, according to the City of Renton's Wetland Management Ordinance. J oas- A00 SvakEs IO FN-TJfIEv A.- [C,1-6�6"M Z • W14?r_k, 6.3.1.1 Vegetation Communities Several vegetation communities occur on the site; these include upland meadow and shrub communities, wet meadow, and scrub-shrub and forested wetland (David Evans and Associates 1991) (see Figure 8). The upland meadow communities are variable in the species composition, but in general are dominated by upland and facultative upland species. Species common to the upland meadow community include: creeping bentgrass, 4grostis stoloneifera; English plantain, Plantago lanceolata; velvet grass, Holcus lanatus; common tansy, Tanacetum vulgare; hairy cats-ear, Hypochoeris radicata; soft chess, Bromus mollis; and Canada thistle, Cirsium arvense. The upland shrub community consists primarily of Himalayan blackberry and Scot's broom (David Evans and Associates 1991; personal observation, Parametrix 1993). The Himalayan blackberry stands are dense, almost impenetrable, and reach up to 15 ft tall. The blackberry stands have overgrown other vegetation (similar to that described above in the upland meadow community). The wet meadow portions of the largest on-site wetland are dominated almost exclusively by reed canarygrass (David Evans and Associates 1991; personal observation, Parametrix 1993). Secondary vegetation within the wet meadows includes creeping bentgrass and common velvet grass. The scrub-shrub wetland community is dominated by young willows; western crab apple, Malus fusca; red-osier dogwood, Cornus stolinifera; Douglas spirea, Spirea douglasii; and black cottonwood. The herbaceous layer consists of creeping bentgrass,creeping buttercup,Ranunculus repens, soft rush, Juncus effusus, and common horsetail, Equisetum arvense. Parametrix, Inc. 49 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin The forested wetland community is dominated b mature black cottonwoods and willows. The herbaceous and shrub layers are similar to the communities described above for the wetland shrub community. p �Dt U�+�PfjK SEC�Idnl 6.3.1.2 Soils �m � (/1lFvU M6.a��Nb Approximately one-third of�the site has either"Len cleared, or cleared and filled with gravel and sand from 12 to 48 inches in depth (David Evans and Associates 1991). A 4-foot-high mound jj%ke �� of fill material covers approximately 1 acre of the site. In addition to the fill material, the siteSfi s S P is also characterized by three soil types: Puyallup fine sandy loam (non-hydric), Woodinville silt SU"44 loam (hydric), and Puget silty clay loam (hydric). Puyallup fine sandy loam is a well-drained soil formed in alluvium. This soil is found on natural terraces adjacent to streams in valleys. The A horizon ranges from fine sandy loam to very fine sandy loam and silty loam. The upper 50 v-1 portion of the C horizon is very fine sandy loam. Non-hydric inclusions of Briscot, Newberg, a A Nooksack, Oridia, and Renton soils and hydric inclusions of Woodinville and Puget soils can ° occur. The central and eastern portion of the site were mapped as Puyallup fine sandy loam ri��u (Snyder et al. 1973). David Evans and Associates (1991) indicate that the on-site soil F'L'-- assessments in the eastern portion of the site are representative of this mapping unit and that the' F`��ro? hard pan varied in thickness between 5 and 10 inches. `„yam Is Hato Phwi tN NAM ads? AO C4"At4QL W FY --*K, Woodinville silt loam is a hydric soil composed of poorly drained material that formed in alluvium on stream bottoms. The A and B horizons range from silt loam to silty clay loam. Thin lenses of very fine sandy loam and loamy sand or peat occur within the horizons. Non- hydric inclusions of Puget, Snohomish, Oridia, Briscot, Puyallup, Newberg, and Nooksack soils can occur. David Evans and Associates' (1991) on-site soil investigation indicated that the western and northwestern portions of the site are representative of this mapped soil unit, and that the depth to the hard pan ranged from 3 to 14 inches. 4 0.- . ? The last mapped soil unit, Puget silt clay loam, occurs on less than one percent slopes. The A horizon ranges from silty clay loam to silt loam. The B horizon is silty clay loam stratified with silt loam, silty clay, and fine sand. This soil unit is mapped in a small portion of the site along the western edge. David Evans and Associates (1991) did not evaluate this soil tape. 0—Al r74,, 07'*4fL S'Oq. td VIGINI DP Pt,� 1/l vLl i , A preliminary environmental site assessment indicated that the source of fill material brought onto Mitigation Banking Site 1 to fill the tributary is unknown without further investigation (Hart Crowser 1991 a). The chemical constituents of the fill material are also unknown. Z4w-repert indi-.ated that Potential in the-fill-eoul� cam io-contac�vwitli�th� shaHow- `� groundwater table in--the-area. If groundwater is contaminated-by-the--fill a:-ptuine inay exist 0� ) which spreads the contamination away from the former tributary to localized--wetlands oraff--site to adjacent properties (Hart Crowser 1991a). In addition,prior to..fillig crf the-tribtitai-q irr the Ner early,-1970s, releases from the Sternoff Metals facility in the late 1960SL may have entered--the tributary. Additional analyses of the former tributary sediments beneath the fill__aR4 7a� /✓ M o t rc,,gs 6'urp Q,i,,cr Parametrix, Inc. 50 City of Renton - DRAFT IM,f.l1i✓nrp 55-1779-07 November 11, 1993 drftmtigpin .hyd'oQgi the-groundwater--flaw d to determine whether v43n n}inants have migrated-throu&the site: -In`'2r second enrviromnen al-site assessment, Golder and At ry dumping- umping er- The City of Renton and the project team evaluated soils at three locations on Mitigation Banking Site 1. Soil test location 1 was excavated near wetland flag M-51 (David Evans and Associates 1991) at a ground elevation of approximately 18 ft (see Figure 10). Fill occurred from the surface to an elevation of about 16 ft. Silty sand with heavy mottles mixed with fill extended to an elevation of approximately 16 ft below the surface layer of fill. Fine silty sand occurred below the silty sand. Active slumping of sediments was evident at an elevation of approximately 9 ft, indicating the depth where water was actively entering the test location. Depth of fill was estimated to be at least 2 feet. Soil test location 2 was excavated in the northwest corner of the site at a ground elevation of approximately 18 ft. Its characteristics were similar to those observed in soil test location 1 (see Figure 10). Fill occurred from the surface to an elevation of about 16 ft. Saturated silty sand mixed with mottles and fill occurred below 16 ft. At an elevation of about 11 ft the sediment was primarily silty sand. The depth of fill was estimated to be at least 5 ft. Soil test location 3 was excavated in the southeast corner of the site at a ground elevation of approximately 18 ft (see Figure 10). Fill occurred from the surface to an elevation of 16 ft. Below 16 ft was a 3/4 inch deep iron oxide layer followed by a silty fine sand fill layer. Woody debris (natural) was observed at 14 ft. Water seepage was evident at 7 ft. The depth of fill was estimated to be at least 4 ft. 6.3.1.3 Hydrology s ac g ID AR, ur Ak C PP"cf 6 iL4 Jf-5. rntirc 6URNTlr1 m"Q of MO. The primary source of hydrology for the existing wetlands on Mitigation Banking Site 1 is precipitation. These wetlands are in depressional areas that hold precipitation prior to evapotranspiration and infiltration. A potential secondary source of hydrology for the wetlands on Mitigation Banking Site 1 is a drainage ditch along the western and northern border of the site. ,ugl the elevations of the wetlands and uplpnds a-Pefr to be considerably higher (at least to 4 St) than the ditch, high flows may oveifTow'the banks of the ditch and enter into the large forested scrub-shrub and emergent wetland (see Figure 8). However, the volume, flow rate, and water quality in this ditch system are not known. �� rr �tten Qwer cr�M �r �yJr in/uM'o�; yt+.ZrC, rYgZUM� �Uf�ofL. A r „t +� „*•n��r���- , once evident within the central portio7, e site (David Evans and Associates 1991), has been disturbed by fill activities s 4, u ace water is flows through the north-soul drainage ditch located just inside the western�boTdary of the site, enters into an east-west drainage ditch, then flows east through a culvert er Metro's gravity sewer system and into the City of Renton C"UvNo WA O D AM To CCU LJ)F/w- o t R" pikr-PT s Parametrix, Inc. c 4 s 5 5E ero aot qr �r rj ? City of Renton - DRAFT 55-1779-07 drftmtig.pin // // November 11, 1993 �y,o�e Oi/J�Crc,C u��ddS h ��%� ��t�a1oh/may wetlands. Once water enters into the City of Renton wetlands, it is retained and leaves the site through evapotranspiration and infiltration. There is no direct outlet (i.e., culvert or day-lighted stream or ditch) from the City of Renton wetlands to Springbrook Creek. Under current conditions,there is no surface connection between the wetlands on Mitigation Banking Site 1 and Springbrook Creek. 6.3.1.4 Functional Assessment F�� gfy,,,q svMn, o,M alAfo DFA David Evans and Associates (1991) evaluated the wetland communities for five functions. In general,,the functional values associated with the existing wetlands were rated as moderate-to-low. Stord*1 ater and Floodwater Control r �/GyP on(n� s�„ne� . Sw f RErAir�AGE �Fii�EfJ'�, All three wetlands/have a seasonal hydroperiod and over 30 percent woody plant cover, factors that are important to impeding surface flows from surrounding commercial and industrial facilities. The overall value associated with slowing surface sheet flow is less for the scrub-shrub wetlands because of their small size. The forested scrub-shrub and emergent wetland is larger and has a discernable drainage corridor along its western and northern borders. Water Quality Improvement /bt or M� I I y �s� , wa�G id d ro� r►.s+�y v�}w•1 (nud {ra. t e�V1 ors s� p The three wetlands contribute minimally to improving d wnstream water quality and filtering of contaminants and other toxicants that may be in receiving waters from adjacent non-point and point source pollutants. The wetlands' usefulness in providing significant water quality function is limited by the ditch along the western and northern borders of the site. The ditch itself provides limited water purification function due to the lack of emergent vegetation. Hydrologic Support All three wetlands had characteristics that indicated ^^^a;,,rt ands seasonal hydrology e smaller scrub-shrub wetlands are in topographic depressions and are somewhat limited in their ability to provide hydrologic support. The larger forested scrub-shrub and emergent wetland is next to an open drainage system along the western and northern boundaries of the site and may contribute to the...hydrologic suppo)-M f adjacerit and downstream wetlands and Springbrook Creek. �t w�flu�dl ar C_ Wow In Groundwater RecharLre The three wetlands are underlain by slowly permeable consolidated till and appear to be temporarily or seasonally saturated. These factors?limit their ability to provide significant groundwater recharge functions. ,,,; .`; UN C.'Pir w Parametrix, Inc. 52 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Biological Support All three wetland communities have somewhat limited species and structural diversity. No unique or water-dependent species and few indications of animals, other than song birds, were observed by David Evans and Associates (1991) or Parametrix (1993). The large scrub-shrub and emergent wetland is more diverse and has greater structural diversity than the smaller scrub-shrub wetlands. It may provide cover and nesting or perching sites for small mammals and birds. The dry upland and seasonally wet meadow areas provide habitat for small mammals that are prey to larger mammals (e.g., coyote) and raptors (e.g., red-tailed hawks). 6.3.2 Mitigation Banking Site 2 400 L-ATi3Of 445' As /✓y760 FOIL I nt Mitigation Banking Site 2 is 13.93 acres. The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, and a fairly large young forested wetland community consisting primarily of cottonwoods and shrubs (see Figure 9). The site was filled within the past 20 years, and with a few minor exceptions, the topography is relatively flit with small�a ressions formed MLAAA u' 0.0 i7 kk" � by heavy equipment conducting grading work. Three wetland were denti � k�ed an' delineated by David Evans and Associates (1991 a) a�r .,""fwo of the wetlands are classified as palustrine scrub-shrub wetlands and the third is classified as a palustrine forested wetland. The wetlands are considered to be Category 3 wetlands, according to the City of Renton's Wetland Management Ordinance. 6.3.2.1 Vegetation Community The young forested community is dominated in a canopy layer by black cottonwoods and willows. Black cottonwood and willow saplings comprise the majority of the shrub canopy along with salmonberry and Himalayan blackberry. Herbaceous cover within the forested community is sparse, but grasses and forbs occur occasionally. The emergent wetlands are shallow depressions in a topographically level upland area and are dominated by bentgrass; foxtail, Alopecurus geniculatus; soft rush; and reed canarygrass. Upland forbs and grasses include clover, Tripholim repens; Kentucky bluegrass, Poa pratensis; tall fescue, Festuca arundinacea; quackgrass, Agropyron repens, and hairgrass, Aira caryophyellea. 6.3.2.2 ¢¢ Soils ,� ��t Lli niN�c$ �fm rU ft��.<�, +'�, q. �. .�.�,.Z {e {7r(o �142GJ�ovtS YA4�l%��j� �LSd ���s The soils on the site are mapped as Woodinville silt loam, a hydric soil (Snyder et al. 1973). However, the majority of the site consists of fill material. The site has been driven on and the compactions, coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in the areas where wetlands have formed on top of the fill. Five soil test locations were evaluated at Mitigation Banking Site 2. Soil test location I was excavated on a topographic high point in an upland area adjacent to Springbrook Creek at an elevation of about 19.5 ft. In general, the soils were uniform from the surface to an elevation of about 10.5 Parametrix, Inc. 53 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin ft. The soils consisted of sandy, silty fill. A blue-gray saturated clay layer was observed at an elevation of about 10.5 ft and extended down to an elevation of about 9 ft. Concrete debris was observed at 4 ft 5 inches. No standing water was observed. The depth of fill was estimated to be approximately 9 ft. Soil test location 2 was also excavated in an upland area adjacent to an emergent wetland community at a surface elevation of approximately 16.5 ft (see Figure 11). From the surface to an elevation of 12 ft, the soil was sandy and lightly mottled with a thin silty clay layer observed at an elevation of about 14.5 ft. At an elevation of 11.5 ft the silty clay sediment was saturated and mottled. Blue clay was observed at an elevation of 10 ft followed by saturated silty clay to an elevation of 7 ft. A lens of organic material with woody debris and black wet sand was observed below elevation 6.5 ft. Water was evident at elevation 5.2 ft and seepage was evident at elevation 7 ft. Plant roots were evident as deep as an elevation of 5.5 ft. -Dept-af-vvr $s ft. The depth of fill was estimated to be approximately 6 ft. Soil test location 3 was excavated in a stand of young cottonwoods, in a wetland delineated by David Evans and Associates (1991 a), at a surface elevation of 16 ft (see Figure 11). Mottled sandy silt was evident at an elevation of 15 ft. The soils had more sandy texture above elevation 15 ft and were siltier below elevation 15 ft. An oxidized iron zone was observed at elevation 14 ft. At elevation 11 ft the soils consisted of damp clay with bright mottles. The depth of fill was estimated to be 4.5 to 5 ft. Soil test location 4 was excavated in an upland area with a surface elevation of 15.5 ft (see Figure 11). The soil consisted of sand and gravel fill with silt from the surface to an elevation of 11.5 ft. The historic A horizon composed of silty clay with mottles occurred within a 10- to 12-inch band below the fill. Below the historic A horizon was a 4-inch gleyed layer with strong mottles. Water seepage was observed at 7.5 ft. Clay was the dominant sediment to about elevation 4.5 ft. Below 4.5 ft the sediment was black wet sand. The depth of the fill was estimated to be 4 to 4.5 ft. Soil test location 5 was excavated in an upland area, had a similar profile to test location 4, and a surface elevation of 16 ft. Fill occurred from the surface to an elevation of about 13 ft (see Figure 11). This soil horizon showed no wetland characteristics. The historic A horizon was observed to 12 inches below the fill. Clay was the dominant soil below the historic A horizon. The sides of the soil test location were glistening, and seepage was evident at 8 ft. Black sand was observed at an elevation of 5.5 ft. The depth of the fill was estimated to be 3 ft. Virtually no difference was observed in the soil texture or composition within the top 3 to 4 ft between wetland and upland areas. Wetlands appear to have developed as a result of fine textured fill material gradually sealing the soils in the topographic depressions on the site, Parametrix, Inc. 54 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin resulting in soil compaction. Once compacted, the soils were able to hold rain water for a short time prior to evapotranspiration and infiltration. A preliminary environmental site assessment made by Kennedy/Jenks/Chilton (1989) indicated that a small potential existed for contamination to enter the site via groundwater. However, a site reconnaisance did not identify significant potential for environmental contamination from current or past site use. A second environmental site assessment made by Hart Crowser (1991 b) indicated that sediment samples collected from Springbrook Creek south of SW 27th between Lind Avenue and Oaksdale Avenue SW had levels of petroleum hydrocarbon identified as oil (57 mg/kg), low levels of benzene (0.06 mg/kg), toluene (0.17 mg/kg), ethylbenzene (0.087 mg/kg), xylenes (0.17 mg/kg), and low concentrations of chromium (100 mg/kg) and lead (15 mg/kg). These levels and concentrations are below the Model Toxic Control Act Method A cleanup levels, and below the WAC Sediment Criteria; no remedial activities were recommended for this area. 6.3.2.3 Hydrology me(i tNfotwrv,non� ! CA7x, ON sPR►N&,6(406K, Wr The hydrology source for the existing wetlands on Mitigation Banking Site is precipitation. Wetlands on this site lack an obvious inlet or outlet, and the elevation of the wetlands is at least 6 to 7 feet higher than the low flow water elevation of Springbrook Creek (10 feet). Evidence of temporary inundation in the depressional perched wetland areas was observed. Saturation to the surface and inundation to a depth of 1 inch were observed by Jones and Stokes (1993) in the emergent wetland areas. The duration of this inundation or ponding is not known. On the day of the site visit in August 1993, inundation and saturation were not observed; however, wetland hydrology was assumed based on depressional topography and marginal hydric soil characteristics. lr 4,4 d e, 6d V*- �fii d�<� � wor 1�,�r isol�z hr d to bus r l y 6.3.2.4 Functional Assessment The functional values associated with the wetlands on Mitigation Banking Site 2 were rated as low by Jones and Stokes (1993) and David Evans and Associates (1991 a) due to the size of the wetlands, lack of structural and community diversity, and an isolated and disturbed nature. Storm Water and Floodwater Control The on-site wetlands provide little, if any, flood or storm ate attenuation due to their size, relative elevation to Springbrook Creek, and lack an outlet for.gi v release of water. Some flood or storm water that enters the site/during extreme flood or storm events likely flows through the uplands and leaves the area thr. ugh infiltration. Water that flows from the uplands to the wetlands leaves the area throug evapotranspiration and infiltration. Parametrix, Inc. SS City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Water OualityImprovement Although the on-site wetlands are relatively densely vegetated, they occur in depressional pans and provide minimal water quality improvements because there is often little or no water flow. Hydrologic Support These wetlands have a limited seasonal hydrology. The wetlands are located in perched pan areas in isolated depressions with no obvious connection to groundwater or Springbrook Creek. These wetlands provided limited hydrologic support. Groundwater Recharee The wetlands are underlain by slowly permeable (due to compaction) consolidated fill. This factor, along with the size and isolation of the wetlands, limits the groundwater recharge value. Biological Support The wetlands provide limited biological support. The young forested and shrub canopy layers provide some cover for small mammals and birds. 6.3.3 Opportunities O ties provided by the mitigation banking program, or that are co tion banking sites, _ semi ed_below-followecf byspe fic oppo�unrt es associated with establishing w&tlands on each mitigation 'n site. (/t U 5C`f r natural ecosystems in the Valley have been severely altered through the years by development, *eestablishing wetlands on the mitigation banking sites provides an excellent opportunity for the City to gain wetland acreage in a historic floodplain area where the added physical functions of storm water attenuation, biofiltration, and biological functions of wildlife corridors will achieve the highest value. __��e;ther mitigation banking program provides an opportunity for the City to errstrfe wh wetlan tion banking is feasible and to evaluate the tec administrative appros to the concept o ation banking. The fact ihat-tie City, as a local sponsor, is committed to establishing a mitigation ng grogrt67ihat is based on public and private partnerships indicates that the City is a ing edge of land use and resource protection conflict resolution. The gation banking pro offers an excellent opportunity to develop the framewor or relatively small-scale banking can be developed without an entire complement of agencies involved in the implementation ess). Parametriz, Inc. 56 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin If-4a-mitigation-banking program s implemented,the City will have an opportunity to-fulfill the policy of no net loss of wetlands. The City of Renton's policy of no net loss-af wetland-acreage, values, and functions can be realized by protecting higher value wetlands, and requiring restoration of disturbed wetlands or creation of new wetlands to offset losses that are unavoidable (City of Renton Ordinance Number 4�36, Section 4, Chapter 32). In meeting the policy of no net-loss of wetland resources, the-C—ity`6F6Vrages creation` of higher category wetlands than the altered wetland, and allows multiple or cooperative compensation for one project within the same drainage basin. F4natip,-the i s-that establishing larger contiguo s wetlands for the purposes of a mitigation banking program will e p . 5provid&g larger, consolidated, and higher quality wetlands rather than small, scattered, isolated, and low-quality wetlands. The.City of Renton currently owns several parcels of property that contain wetlands (see Figure 4). The-intent of the City is to retain the natural features of these parcels as open space and natural reso4ee corridors. The wetlands on these parcels are currently providing some of the recognized functions, of wetlands, including flood storage, wildlife habitat, water quality improvement, and groundwater recharge. Restoring wetlands on the two mitigation banking sites would provide an opportunity to add acreage and quality to the wetland resource base within the City. The City desires to use the mitigation banking program as an opportunity to reverse the trend of wetland losses and begin a positive-trpnd toward wetland gains by restoring some of the historic wetland systems in the Black River Drai Basin. The mitigation banking program provides an opportunity for the City to consolidate some wetland mitigation in advance of wetland impacts ,-The c=s lidated wetland mitigation approach also provides-epportunities-€ar-ehievingthe.w,et miti -atien-hiking-progr gals-and objectives, e le. The mitigation banking program concept can benefit both the community and users of the bank as well as the natural resources that use and/or depend on wetland systems. The bank program provides an opportunity for individual users where the details of wetland compensation are preplanned, constructed, and maintained by the City, and where the costs to the developer have been determined. 6.3.3.1 Opportunities in Mitigation Banking Site 1 rQN(-¢ of �FPap-ruN �y 04 To r/ C PLC �i �4/Lw1^Tav✓�l Protection of Wetlands and Increased Functional Value Mitigation Banking Site 1 is located west and south of large, high-value City-owned wetlands (Category 1, wetlands based on the City's rating system). The proximity of Mitigation Banking Site 1 to high-quality wetlands provides an opportunity for increased protection of restored wetlands from other uses and destructive human activities. Proximity of this site to higher-quality wetlands also provides an opportunity for increased functional values of restored and existing wetlands, such as providing connections between wetland systems, and providing habitat corridors Parametrix, Inc. 57 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin and open space for passive uses within and between the neighboring wetland systems and the mitigation banking site. Flood Storage and Attenuation (,oC�L FLokK, 70 sue, -- F�S'r0(4 ./�t. Ley^�rJ �,Trw� R".r Cr.•y Cw4rf_A,'O (fa-Si Mitigation Banking Site 1 provides an opportunity to increase the acreage capacity of flood storage. This site may provide storage opportunities for localized runoff from adjacent and upstream developments, as well as backwater storage from nei hboring wetlands. fh,s c_W U .ly+ em�,t/..( f'�-lYef'Itso��J�F/Pn. r , �;, Pa .ef 6e �, ' lie el d, n a -quality--plaan being eval�ted ty. vreate--a �vate� + Ne Ei would :y high=flow bypass system. This alternative would involve- ealrung am a"Spi�nghrotk Creek-so that flows from SW 43rd Street would flow north along the west side of Mitigation Banking Site 1, then flow east toward Springbrook Creek. Minimum flows needed to support fisheries resources would still flow through the existing Springbrook Creek channel between SW 43rd Street and SW 27th Street. Some flood storage and flow attenuation could be provided under this scenario on Mitigation Banking Site 1. If realigning a portion of Springbrook Creek becomes a preferred alternative, a design feature could be incorporated that would route the water through Mitigation Banking Site 1 before entering back into Springbrook Creek. This action would positively impact Mitigation Banking Site 1 by providing greater hydrologic support for the entire wetland system, as well as providing the hydrology necessary to support hydrophytic vegetation reestablished in the upland fill areas of the mitigation banking site (i.e., the-reslQred wetlands). Water Quality Improvements The restored wetlands can help improve local water quality conditions by acting as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways that enter into the drainage basin in Renton. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live, work and visit in Renton. While the wetlands to be established on Mitigation Banking Site 1 have multiple values, one of the primary uses could be to improve the quality of downstream aquatic environments. j i�q c4 rtAI c�awn 3f 1'e.A,,,,. Wildlife Habitat Because of its size,proximity to higher-value wetlands, and relatively greater isolation from urban development, Mitigation Banking Site 1 provides an excellent opportunity for greatly enhancing both aquatic and terrestrial wildlife habitat. By restoring a variety of wetland types, and by buffering these areas from the impacts of nearby development, a diversity of habitats will be established; that diversity will benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding upon existing natural systems and restoring habitats in areas that have been damaged by human activities ensures better survival of wildlife and provides wildlife viewing Parametrix, Inc. 58 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin opportunities. The concept of habitat corridors also enhances the value of the area for aquatic and terrestrial wildlife. Public Access and Education The City of Renton recreation plans r 'fir t ' d show trails in close proximity to Mitigation Banking Site 1. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban storm water quality, etc., and could be offered by interpretive signage and printed materials. Planned trails and wetland and wildlife observation points could provide opportunities for public enjoyment of Renton environments. The wetland environment in Renton could become a favorite place to recreate and learn, particularly if used by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington and South Seattle Community College, these wetlands could be the subject of further study by interested wetland research scientists over the coming decades. 6.3.3.2 Opportunities in Mitigation Banking Site 2 Pi-69 Of- o(P°ffu"Irl Duk ra 5t7k i°L*-) Al,,r anvjl? Improved Flood Control u fiAtt �_,C&U OW.4,,oFIG To s/,J? Mitigation Banking Site 2 has the capacity to provide flood storage. Based on the size of the site, along with elevation information, the site has the potential to accommodate approximately 14 to 30 acre feet of storage (depending on the elevations of the restored wetlands and whether existing wetlands are excavated). A flood-storage function could be established by installing a conduit through the dike at an elevation designed for a particular storm event (e.g., 2- or 5-year event). Flood waters would then enter Mitigation Banking Site 2 from Springbrook Creek, be stored and attenuated in the restored and existing wetlands and reenter Springbrook Create at an engineered and constructed outlet structure at the northeast corner of the site. A small proportion of flood water would be lost due to evapotranspiration and infiltration. This would reduce impacts to downstream areas from storm runoff originating in the Valley. This flood storage improvement can also provide multiple benefits, such as wildlife habitat. Water Quality Improvements d't ►S' -by acting as biological filters to remove sediments, certain nutrients, and other water pollutants �d from the drainageways, the restored wetlands can help improve local water quality conditions in (.� Renton. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant Se 1 water-oriented experience for those who live, work and visit in Renton. While the wetlands to �0' be established on Mitigation Banking Site 2 have multiple values, one of the primary uses could f be to improve the quality of downstream aquatic environn'rents. Parametrix, Inc. 59 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Wildlife Habitat and Corridor Mitigation Banking Site 2 is next to Springbrook Creek, ---The 's proximity tagbreok Creek offers an opportunity to provide aquatic and terrestrial wildlife linkages to other wetlands, water bodies, and open-space areas, as well as downstream benefits to fish and wildlife. Another identified opportunity is to have some wet meadow areas that become relatively dry in late spring and summer for small mammal shelter and foraging. These smaller mammals in turn act as a food source for predatory birds, such as red-tailed hawks, and larger mammals. Providing this type of wetland habitat, along with other wetland habitats (e.g., open water aquatic bed), increases the overall diversity and features inherent }n a higher quality wetland system. S� �r,. /n.t�C�Sd. 7f t T4 t 1"ate �✓M � C. OF �.. tA, Finally, the Renton community can be eAanced ty restoring a variety of wetland types, linking them to other City-owned, high-quality wetlands, and managing the City-owned wetlands as a connected system. I Jrf ewovQd or In vaS/tA S�eGc�• 10(/W4 �,�,r �LlMi aN U to wf/✓C lft4fS f rr Public Access and EducationhCie slew Stit'�+/�f' � (c.St�rc Grrs/icy o.+Gl'/u�l on f/fe '2. . The Cityof Renton recreation plans t o r t show trains along Mitigation ...................................... Banking Site 2. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban stormwater quality, etc., DNA and could be offered by interpretive signage and printed materials. Planned trails and wetland and wildlife observation points could provide numerous opportunities for public enjoyment of Renton environments. The wetland environment in Renton could become a favorite place to recreate and learn, particularly if used by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington and South Seattle Community N' College, these wetlands could be the subject of further study by interested wetland research scientists over the coming decades. 6.3.4 Constraints Constraints associated with restoring both mitigation banking sites are presented below. Where appropriate, differences in constraints for each site are identified. 6.3.4.1 Enhancement Credits The City of Renton's Wetland Management Ordinance does not recognize enhancement as an acceptable form of c me�satory mitigation Them-are,4pproximately 10 to 15 acres of existing P6, tq wetlands that coul�be enhanced and used for mitigation banking ' ed .in the€utur A5 lls G?1C.T1 t Parametrix, Inc. 60 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.3.4.2 Hydrology and Groundwater Perhaps the most challenging current constraint is the lack of seasonal depth-to-groundwater data (assumes that groundwater will be the primary source of wetland hydrology or will augment other sources of hydrology such as precipitation and surface water). There is little available on-site water to support restored wetlands. Wetlands on both site appear to,have developed as a result of sur-faee voker-aecu n 4ation-due-tcrdirect precipitationf�slight depressional areas where, over time, finer sediments have accumulated and reduced soil permeability. Hydrnlogic-support-for wetlands on Mitigation Banking Sites-1 -and2-appears tiod be from�l�ggca} preeipita ien. Thus, the most significant consZain4t associated with establishing on Mitigation Banking Site 2 is determining tl� sources of hydrology and how to manipulate the sources to meet the hydrologic needs of restored wetlands. Wa II ;,0- sr,(r 1c.,4ej The available information on existing hydrology for Mitigation Banking Site 1 is not-idequate mre. act iaK. to develop„ospeciiic s�t���deigns that could��b� used tg prepare bid package for restoring the uplands to wetlands.'No grou �dwa er nomtormg has been done,on tf'e site to establish"seasonal fluctuations which could aid in the design of created wetlands (assuming that groundwater is one potential source of hydrology for Mitigation Banking Site 1). Ideally, the level of groundwater should be measured for at least 1 year. Groundwater wells constructed of PVC pipe could be installed and monitored over the late fall ntejr and spring. This additional information would allow the conceptual site design to be o i to reflect seasonal fluctuations in groundwater hydrology�An alternative and/or additional,sgu�rFe p f hydrology is the ditch that runs south to north along the westernprogerboundary. Colp jig quantity and quality of the water in this ditch�is �e ` li d tamed site plan ca be produced and appropriate structures ore a e oan-be engineered. y` y_data--ass© iated the western and northern boundaries of Mitigation-Banking Site 1, groundwater-data-and needed to complete a detailed site design for Mitigation Banking Site 1 were provided to the City-in_a-Novernber 4, 1993 letter {Appendix-ee . The amount and quality of hydrology inf rmat' a licabse to 'ti atig3n Banking Site 2 is better than for MitigationiBanking Site I" ' may" and rrieasured (ab utWb.%.$),_ In atign is also avail '-, on mean daily -and-v,+ater os��e�rt a 70 . One alternative for bringing water into Mitigation Banking Site 2 involves pumping water directly from S rm brook Creek. The pumped water would provide the P P g Y P � g P P primary source of hydrology for the restored wetlands and would augment the hydrology in the �umP existing wetlands. Pumping of water requires an energy source and installation of appropriate v rw- VeT160 structures; costs associated with this alternative are being evaluated. A second alternative �U ` , involves installing a well on the site west of the dike, and pumping groundwater from the well. (aNr��G�N The advantage of a groundwater well over pumping water directly from Springbrook Creek are � °that the quality of water is more reliable and the amount of water needed can be more readily controlled. Although groundwater was observed at an elevation of about 7 feet during the site visit in August, 1993, the depth of the well needed to capture groundwater still needs to be 1'W4005 /64 f C14 P° Parametrix, Inc. 61 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin determined. Monitoring groundwater levels in late fall, winter and spring would provide more information that can be used to modify the site plans being developed for the site and to np determine, if necessary, the depth of the well needed. The disadvantages to using pump (either from Springbrook Creek or a groundwater well is that pumps require an energy source and r maintenance, and are entirely artificial. Arm.alternative is to install a gravity fed hydraulic system in Springbrook Creek so that water flows freely into Mitigation Banking Site 2. This alternative will require relatively extensive excavation of the existing uplands to establish elevations that would match the surface elevations in Springbrook Creek during low flow periods and an engineering design that will prevent fish tmpingemc nt an entrapment. In addition, excavation of the existing uplands to elevations lower than the existing wetlands may result in dewatering of the existing wetlands. Thus, portions of the existing wetlands may also need to be excavated and/or altered to ensure that there will still be a hydrologic source for the existing wetlands, or those portions that are not altered. The site plans being developed for this site include an alternative that would result in altering existing wetlands, and an alternative that would not alter the existing wetlands. 6.3.4.3 Issues with King County Drainage District No. 1 0/ki SrRvE<, Lim ,�9 F�^'c�ria.� c�us£ of pKco�riNu�rlES gar The King County Drainage District may place restrictions on work associated with Armes. 5n)Wr. cu#A4 16� -For-e�, installing a conduit to allow high flows from Springbrook Creek'C �V�"J 'at,1. tT into Mitigation Banking Site 2 could apaei -in tkealley. A alb The Drainage Di�str'ct�may^have concerns about the effects on_the-strnct-ural-�egrity-of-the-dike fir mstallatiori,.o tl�ie conduit. 7�us5--the- (fM �a possibility-of-altering-a portion of-the WUorua¢, to be discussed with the Drainage District. ,am chl,ri fio 6.3.4.4 Balanced Cut and Fill r a E 5m6 Because of the depth to groundwater observed on both sites in�A, unt 1993, and the fact that filling of both sites has placedground elevations weR above floodplain elevations, the costs to excavate and remove soils would be high. In addition, these conditions would make it costly to establish a direct hydrologic connection between restored wetlands on Mitigation Banking Site 2 and Springbrook Creek. Thus, a balanced cut-and-fill scenario is unlikely given the depth to which excavation must occur if created wetlands are to use groundwaterfhy"dr'orogy. If groundwater hydrology is to be used, export of significant amounts of material is likely. Although the costs for excavation would be relatively high, once hydrology is obtained wetland creation success probability increases with correspondingly lower landscape costs (i.e., plant material costs). -te,a enr-hY&r-6-1bgy for the restored wetlands on Mitigation-Banking.Site.-2, a-more-balanced-cut=and-f Il scenario-is- likely, and export of soils will be less,---- Parametrix, Inc. 62 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.3.4.5 Urban Development Urban development is in close proximity to both sites. Lots zoned for industrial and-eonnnerci'al uses are directly north of Mitigation Banking Site 2. A major thoroughfare, OakWe Avenue, is directly west of the hsite. Mitigation Banking Site 1 is relatively more isolated from urban development, and �11 a only a portion of a Oa Jdale Avenue along one of its boundaries ? once construction of Metro's gravity sewer system is complete. Nevertheless, this site has adjacent' evelopment along its southern boundary, and further development in this area is likely to occur. t Existing and future urban development are not significant constraints�khey are a reality that needs to be considered when deciding what types of wildlife functions can realistically be expected. 6.3.4.6 Existing Potential Seed Bank The current soil seed bank on both sites may not contain some of the important plant species (e.g., rushes, sedges, bulrushes, bur-reed, cattail, water parsley, water lily) which might be used in the mitigation banking wetlands. Existing plant communities express what is likely held in the seed bank (i.e., black cottonwood, red alder, salmonberry, reed canarygrass, and Himalayan blackberry). However, it is reasonable to suggest that the historic seed bank (prior to filling) contains some of the important plant species that would add structural and species diversity to the mitigation bank. For example, a review off some historic aerial photographs taken of the tributary to Springbrook Creek before it was filfiQicates that-s@te- tt-spectie� ? f -------.._ -----_ -a11C--1�ivef9it,y'_ Sa✓r:e vi• f LP3e }�fG�,r r+', •y i"ua�•c ���f�-�, 6.3.4.7 Soils / Little wetland soil (e.g., peats or muck) is available on either site to use in construction of new wetlands. However, if the clay found within soil test location 2 on Mitigation Banking Site 2 is abundant over the site, it may be suitable for lining some restored wetlands. However, an appropriate planting medium, such as topsoil, may need to be imported to the sites to allow the roots of plants to become established. 6.4 ACREAGE AND TYPE OF MITIGATION FEASIBLE FOR THE MITIGATION BANKING SITES 6.4.1 Acreage of Mitigation Feasible on the Mitigation Banking Sites Combined, both mitigation banking sites can provide a total 19.35 acres of restored wetlands. Specifically, Mitigation Banking Site 1 consists of 30.97 acres of land. Of this total, 18.78 acres are considered to be wetland, leaving a total of 12.19 acres of upland available for establishing wetlands and buffers. Mitigation Banking Site 2 consists of a total of 13.93 acres of land. Of Parametrix, Inc. 63 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin this total, 6.77 acres are wetland, leaving a total of 7.16 acres available for establishing wetland communities and needed buffers. fid The City will nae�e-use 543 acres of the total acreage to complete the compensatZ)3 igation required by its agreement with the Glacier Park Company. This leaves a total ofacres of uplands that can be restored to wetlands. However, the City's Wetland Management Ordinance 1(!►� D5 �w requires that impacts to buffers must also be compensated. Therefore, a portion of the existing upland, especially around the perimeters of the sites that are closest to major thoroughfares (i.e., Oak�#le Avenue) may need to be used to create buffers. The site plans for the two sites are 1� being developed to maximize the amount of wetland acreage. 6.4.2 Type of Mitigation Feasible for the Mitigation Banking Sites The types of feasible mitigation(i.e., functions to be restored,vegetation communities)are similar in nature for both mitigation banking sites, and are based on the review of available information on characteristics of wetlands in the Valley, the site visit, and knowledge of wetland systems in the Pacific Northwest. Restored wetlands on Mitigation Banking Sites 1 and 2 could support communities and provide functions as described below. 6.4.2.1 Communities Emergent Community Emergent communities that could be established as part of the mitigation banking program include shallow marsh and deep marsh. Wet meadow is not included because portions of the existing wetland communities are already seasonally wet meadow. Shallow marsh wetlands are characterized by relatively deep inundation in the wet season; they can tolerate dry conditions in late summer. Vegetation that is typical of these conditions can include: spikerush, Eleocharis palustris; water plantain, Alisma plantago-aquatica; slough sedge, Carex obnupta; hardstem bulrush, Scirpus acutus; small-fruited bulrush, Scirpus microcarpus; and narrowleaf burreed, Sparganium emersum; water parsley, Oenanthe sarmentosa; slender rush, Juncus tenuis, dagger- leaf rush, Juncus ensifolius. Open water habitat/deep marsh Open water components and deeper marsh habitat may also be established on the sites. In order to establish these types of communities, it may be necessary to excavate to or below groundwater depth or create this wetland community on impermeable linerg.r his wetland community is characterized by relatively deep inundation in the wet season; it does not typically dry out during the dry season. Vegetation that occurs within this community includes: floatingleaf pondweed, Potomageton natans; water plantain, Alisma plantago-aquatica; yellow pond lily, Nuphar polysepalum; hardstem bulrush, Scirpus acutus; and marsh speedwell, Veronica scutellata. Parametrix, Inc. 64 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Scrub-shrub Habitat Scrub-shrub communities are often more diverse because they are relatively young communities in an early stage of succession. Scrub-shrub communities are typically dominated by one shrub, with other species occurring as sub-dominants in various percentages. The scrub-shrub community that could be established on Mitigation Banking Site 1 includes a scrub-shrub willow community, Salix lasiandra and sitchensis; with a mix of red-osier dogwood, Cornus stolonifera; swamp rose, Rosa pisocarpa; western crabapple, Purus fusca; hardhack spirea, Spirea douglasii; twinberry, Lonicera involucrata; currant, Ribes spp.; and ladyfern, Athyrium felix femina. 6.4.2.2 Functions 45 Sew/or t s /411vlA."A 4 sh «, e cw Floodwater Storaze and Attenuation Mitigation Banking Site 1 has a relatively high potential for providing flood water storage and r attenuation. To provide details on the sites capacity to accommodate flood storage, detailed ({ 0 topographic information about the site and it tionsI6 to tfie-flobdp ain)is needed before the A,,,�r� k exact storage capacity of the existing and restored wetlands can fie calculated. However, a t tributary to Springbrook Creek once occurred in the central portionof Mitigation Banking Site 1 and wetlands associated with this relict tributary probably provided some attenuation of flood flows. Mitigation Banking Site 2 also has the potential to provide flood storage capacity and attenuation. Based on available information on topography, relationship to the 100-year flood plain, and flows in Springbrook Creek, Mitigation Banking Site 2 has the capacity to store approximately 15 acre feet of water (this assumes that the majority of storage capacity would occur in restored wetlands and not in existing on-site wetlands). However, the storage capacity could increase to up to an estimated 30 to 40 acre feet if the existing uplands and possibly some of the existing wetlands are excavated to elevations that are similar to surface elevation of Springbrook Creek during low flow periods. in f,I fray"' The value of wetlands for stogy R , -and--aftenuation is often limited during mid and late i r winter when the soils have been ie after periods of significant precipitation. The goal of S ,u* providing flood water storage and attenuation on Mitigation Banking Sites 1 and 2 will involve 5� the establishment of various types of communities at various elevations so that soils vary in dryness (more permeable soils) and wetness (more impermeable soils such as clay). The existing wetland communities have wetland soils that appear to remain dryer during fall and winter sto events—storage and attenuation may be significant in these areas. Parametrix, Inc. 65 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Water Oualily Improvement Wetlands can improve water quality by slowing the movement of water and causing sediments and any associated pollutants to settle and be deposited on wetland substrates. Currently, the source of hydrology for the existing wetlands on both mitigation banking sites is precipitation. Restoring wetlands on both sites requires a water source to be identified and routed into the restored wetland communities. The quality of water that may enter Mitigation Banking Site 1 from upstream sources or from the ditch along the western boundary of the site could be improved (this assumes that there a water quality issue associated with upstream waters) by passing the water through the restored and existing wetlands. Water quality problems in Springbrook Creek have been documented and described in the East Side Green River Watershed Plan (R.W. Beck and Associates 1991) and the Black River Drainage Basin Draft Water Quality Management Plan (R.W. Beck and Associates 1993). If the source of hydrology for the restored wetlands on Mitigation Banking Site 2 is obtained by using water from Springbrook Creek, the wetlands can potentially provide a water quality improvement function. Even if the source of hydrology for the restored wetlands is groundwater, Mitigation Banking Site 2 can still provide water quality improvement functions if a system is designed to allow flood waters to enter the site. The surface of leaves, stems, and litter from dense herbaceous and woody wetland vegetation restored on the site can physically catch and filter suspended sediments. Wetland vegetation provides a large surface area for the attachment of bacteria, which are the primary mechanism for nutrient reduction. In addition, certain toxins can be broken down by plant bolic �, r�.processes; other toxins remain within the plant until the plant decomposes `1�'za s that dTe ompose slowly during months with relatively high water flows are excellent sources of biofiltration. Smaller sediment particles may also settle in standing open water/aquatic beds, providing additional improvements to water quality. Wildlife Habitat and Downstream Biological Support Providing ecological habitat is among the easiest functions to restore in wetlands and their buffers (Ecology 1993). Components of high-quality habitat that would be established on the Mitigation Banking Sites include: high structural diversity [i.e., emergent, shrub, and forested (existing) canopy layers for birds]; relatively undisturbed corridors between the site, City of Renton Wetlands, and Springbrook Creek; a relatively high diversity of native plants; and intermittent and seasonal open water/deep marsh components. Several of the plant species listed in Section 6.4.2.1 are known to provide important wildlife values. For example, slough sedge seeds provide food for waterfowl (especially pintail and mallard ducks, and shovelers)and for soras, dowitchers, grouse, juncos, and sparrows. Parametrix, Inc. 66 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Social and Aesthetic Values, and Recreation and Education Opportunities A portion of the mitigation banking sites could provide educational and passive recreational opportunities. Both sites could be considered open space. Open space, education, and recreation can all be factored into the design to relate to the positive use of a wetland by people. Wetlands are typically highly rated if they provide visual relief within a developed/developing landscape, allow access for passive recreation, and are used as outdoor classrooms. Aesthetic values of a wetland are often related to the size of the wetland/wetland system, presence of an open water component, diversity within the system, and wildlife use. .r-,'6r 6.5 WETLAND ACREAGE POTENTIALLY ELIGIBLE WITHINATHE BLACK RIVER DRAINAGE BASIN FOR USE AT THE MITIGATION BANKING SITES Two primary sources of information were used to assess the size and categories of wetlands within the Black River Drainage Basin whose impacts may potentially be offset at the mitigation banking sites. The information sources were Jones and Stokes (1991) and R.W. Beck and Associates (1993). Table 1 was created using information on wetlands from their earlier documents. Table 1 shows the categories and sizes of wetlands within the Black River Drainage Basin. Approximately 37 wetlands were identified within the Black River Drainage Basin—the majority occur within the City of Renton limits (see Figure 1). Of all the inventoried wetlands, 35 have been classified as either Category 1, 2, or 3 wetlands, according to the City's Wetland Management Ordinance (City of Renton 1992). Of these, 17 wetlands (48 percent) are rated as Category 3 wetlands, 15 (43 percent) are rated as Category 2 wetlands, and 3 (9 percent) are rated as Category 1 wetlands. -) .571 (--1-4C^T16 caop I r'9 Assuming that the City will consider mitigation proposals for the mitigation banking sites that involve impacts to Category 1, 2, and 3 wetlands, a total of 37 wetlands are potentially eligible to use the mitigation banking sites. The 37 potentially eligible wetlands represent a total of approximately 445 acres. Estimates of wetland acreage by wetland category are provided below in Table 4. a5S�'MM 16551,!�eX 8/NW 1A)0sU1bUA(- "\7 'Fi 111 ,C Table 5. Approximate acreage of wetlands in the Black River Drainage Basin. Wetland Category Acreage (approximate) 1 126 (28%) 2 217 (48.5%) 3 71 (16%) Uncategorized 31 (7.5%)Parametrix, Inc. 67 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.6 FEASIBILITY OF MITIGATION BANKING PROGRAM The feasibility of the mitigation banking concept is relatively uncomplicated. ,After areas are acquired and wetlands restored, created, and/or enhanced, the acreage and/or functional value of the created, restored, and/or enhanced wetlands is measured and a total number of mitigation credits are established for the bank (Ford 1991). As wetland development in..the..Black lamer Drainage-Basin- is permitted by-tie-E-it�,, existing acreage and functions of wetlands that would �v� fA&+ be lost are measured by the same method used to assess acreage and function of the-banked_C- �s wetland mitigation, and debits are made to the bank, reducing its credit balance. The terms by which credits are traded for units of permitted wetland loss—the trading ratio—are typically set"=h��T�, by the lead regulatory agency to achieve no net loss of wetlands or wetland function. Eventually, nU, all of the credits are withdrawn from the bank to compensate for wetland losses, and a new bank can be established by rehabilitating or creating new wetland habitat (Short 1988). Wetland mitigation banking was developed as an administrative strategy to deal with compensation for unavoidable project-related resource losses. This form of mitigation differs from concurrent compensatory mitigation in that the a mitigation is not necessarily exclusive to one specific project and the mitigation occurs in advance of project impacts (Figure 12). Mitigation banking is intended to involve only those habitat protection, creation, or improvement measures taken expressly to compensate for habitat losses associated with future development actions (Short 1988). Mitigation banking requires that a plan be conceived and implemented that identifies the location of wetland resources, characterizes wetland functions, develops an overall scheme for wetland resource management prior to any proposal for wetland alteration, and identifies the implementation process for using the mitigation banking program. Short (1988) describes mitigation banking as follows: ...mitigation banking is similar to maintaining a bank account. A developer undertakes measures to create, restore, or preserve fish and wildlife habitat in advance of an anticipated need for mitigation for future project construction impacts. The benefits attributable to these measures are quantified, and the developer receives mitigation credits from the appropriate regulatory and/or planning agencies. These credits are placed in a mitigation bank account from which withdrawals can be made. When the developer proposes a project involving unavoidable losses of fish and wildlife resources, the losses (debits) are quantified using the same method that was used to determine credits, and a withdrawal equal to that amount is deducted (credited) from the bank. This can be repeated as long as mitigation credits remain available in the bank. An alternative off-site mitigation program to mitigation banking is concurrent compensatory mitigation. Concurrent off-site mitigation allows a project proponent to develop a project site and mitigate concurrently for impacts to wetlands at a selected site within the same drainage basin, or other defined area. Parametrix, Inc. 68 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtigpin Models for Compensation of Wetland Impacts / TIME TIME .,•:sr. .y; x�� ..........:>: PROJECT ..... .:�� IMPACT Functions Project Evaluation and r Wetland Mltl ation Values g Extent of Impact Assessment Creation Priorities "' . Functions and Monitoring Values Assessment • Mitigation Options - Avoidance/ Compensation - On-site/Off-site Functions • Determine Mitigation Wetland and Compensation Values Priorities Creation Requirements Assessment Monitoring i i CONCURRENT COMPENSATION MITIGATION BANKING :::: MR P Figure 12. Types of Mitigation Programs The City's Wetland Management Ordinance allows project proponents to consider off-site mitigation for wetlands [Section 4-32-6 (e and f)] in addition to on-site mitigation. The City also allows project proponents to combine mitigation requirements from different projects or to pool mitigation requirements of several developers. However, several developers, or one developer, that own many parcels containing wetlands would need to time their projects so that impacts and compensation for those impacts occur concurrently. The primary differences between a concurrent off-site mi Xcurs ation program and a mitigation n banking program are that: Ql concurrent wetland mitigatio strictly within the context of a regulatory permit process, (2) mitigation occurs outside of the context of aplanr that identifies regional and local goals for allowing resource protection and economic development, (3) the responsibility for mitigation(site acquisition through implementation,monitoring, etc.) lies solely with the developer, and(4) mitigation projects would be piece-mealed on one larger site and there is little control over how individual mitigation projects are implemented, monitored, and managed. On a technical basis, allowing a developer to use a portion of one of the two mitigation sites for concurrent compensatory mitigation requires the developer to leave the remaining upland undisturbed for another developer to use at a later date. __For ex�mpLe,.assume.thatAho-C--iVf--ttses Mitigation Banking Site-2 to fulfrll-its--obligation-to vi e-5:33--acres-ef-e©mpensate y-wetland developed-4gy--the Glacier..Eark_,Company. Implementing the mitigation-foronly 5.33 acres will_leayz-atot l-ef1.83 acres of additional upland that could be restored to wetland. -How,will--the-i ity ef afdtfatore only 5.33 acres and leave the remaining upland acreage unaltered for-another--developer to patezgeffy-use9 Assuming that the remaining upland acreage will be left undisturbed for a future off-site mitigation project,the activities undertaken to complete the first off-site mitigation project may affect the success and viability of the second mitigation project. A wetland mitigation banking program developed and implemented by the City, with assistance from the private development community, is recommended because the potential advantages outweigh the potential disadvantages, and the potential disadvantages are not insurmountable. The advantages and disadvantages associated with the feasibility of establishing a mitigation banking program are provided below along with recommendations for addressing the potential disadvantages to mitigation banking. 6.6.1 Advantages of Mitigation Banking • Mitigation banks designed and sponsored by resource agencies with experience and motivation to complete the mitigation project usually have a greater potential for successfully meeting program objectives than do mitigation projects designed and Parametriz, Inc. 70 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmog pin • With mitigation banking, credits are based on wetland values that are present on the site rather than potential wetland values that are anticipated for off-site compensatory mitigation projects. • Monitoring, evaluation of mitigation compliance and success, and implementing contingencies are easier and more efficient with fewer larger sites (Short 1988). 6.6.2 Disadvantages of Mitigation Banking Program • The general public may perceive that the bank is available to compensate for impacts that would otherwise be avoidable. • The development community may perceive the bank as a mechanism to ensure blanket approval of future permit applications. • There is a large initial investment of time and expense involved with establishing a mitigation banking program. The disadvantages to a mitigation banking program in the City of Renton are not insurmountable. The City of Renton Wetland Management Ordinance requires that project proponents take steps to avoid and minimize impacts to wetland resources before considering any form of compensatory . 7 mitigationti.e�. o -sit_off-site,consolidated off-site mitigation,or mitigation banking).'Provided that the City continues to use thislsequencing system, or a surrogate,.and evaluates each project permit application according to pertinent laws, policies, and guidelines, the bank is not likely to be used to compensate for project impacts that may be avoidable. One intent of the mitigation banking program is to provide an economical option to other forms of mitigation for projects proponents whose projects result in unavoidable losses to wetland resources. The mitigation plan will require that public and private project proponents meets certain eligibility criteria, and standards associated with the criteria, before using the mitigation banking program. Using eligibility criteria to determine the appropriateness of using the mitigation banking program will help to eliminate perceptions, if any, that the mitigation banking program will ensure blanket approval of future permit applications. The City may have to finance and take the lead on the initial restoration of the total available upland acr ge�tto VV��etl ds pn ne of thetwo mitigation banking sites i.e., Mitigation Banking �1TT' f /rII i, rnr`4a�,� �gtirir 1TgaQ.,+ �i / �l�cry Site 2)./tThe City cQAe"n t7an�c t ie rem�mng wetland acreage are-e-empleted)-to encourage private participation. The -ity-needs_tn-prau' mitigation pur-suant..to-its agreement.with..ie Glacier Park--Company.-If-the-City used-Mitigation Banking Site-2-ta-€idfill this obligation;-Xwould appear to be more cost-effective i entire upland-portion-of Mitigation Banking Site 2 versus-just4he-54. 3-,acres because the total acreage available on this site is 7.16 acres. Parametrix, Inc. 72 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmt ig.pin o 91317 f arametrix, Inc. Consultants in Engin Ind Environmental Sciences 5808 Lake Washington Blvd. N.E. Kirkland,WA 98033-7350 JUN 171994 206-822-8880•Fax:206-889-8808 CITY OF RENTON Engineering Dept Scott Woodbury June 13, 1994 City of Renton 55-1779-07 200 Mill Avenue S. Renton, Washington 98055 Lear S'ic6a: This invoice is for work completed from April 1 through May 31, 1994. The primary work completed was attending and participating in an interagency meeting. Talasaea provided the site designs mounted on boards for the City's use at the agency meeting. Sincerely, PARAMETRIX, INC. Tracey P. McKenzie enclosure ��� Printed on Recycled Paper Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd. N.E. Kirkland,WA 98033-7350 206-822-8880-Fax:206-889-8808 V U 141 Mr. Scott Woodbury ,1994 May 3, 1994 City of Renton �p� 6 55-1779-07 200 Mill Avenue SouthC�NSON Renton, WA 98055 o g►n Bring Dept• E Re: Invoice #003036 Dear Scott: This invoice covers work completed by Talasaea Consultants in late December,January, and February to revise site plans for mitigation banking site 1. Parametrix provided assistance to Talasaea in preparation of the revised site plan. Please call me at (206) 822-8880, if you have any questions or need more information. Sincerely, Tracey McKenzie Enclosure ��� Printed on Recycled Paper MAY-lb-94 SUN 18:40 PAKAME'1'K1X FAX N0, 206 889 8808 F 01/06 Post-it-Fax Note 7671 Date s. pages To S W 10. From 9LUd Phone# Phons k C�iy/ '� r�i✓0 Fax# Fax /P it LdUk Xcow i e- G/ MEMORANDUM to; Scott Woodbury May 9, 1994 from: Tracey McKenzie4PP--i 55-1779-07 re: City of Renton Mitigation Banking Program - First Agency Meeting Attached are draft minutes to the meeting for your and Ron's review and comment. Your changes, edits, etc.will be incorporated into a final memorandum of minutes; a revised copy will be sent to you. MAY-15-94 SUN 15:41 PARAMETRIX FAX NO. 206 889 8808 P. 02/06 to: Files from: Tracey McKenzie May 15, 1994 Page 2 MINUTES TO MEETING AGENCY MEETING NO-1 MAY 2, 1994 The first agency meeting was held at the City of Renton Community Center to discuss the City's proposed wetland mitigation banking program. In attendance were the following; City of RentQ.n Ci Consultant Agenc_ y Staff Ron Straka Tracey McKenzie Phil Schneider - WDFW Scott Woodbury Dennis Carlson - USFWS Ben Meyer - NMFS Eric Stockdale - Ecology Gail Terzi - Corps T.J. Stetz - Corps Other Dick Larson - Senator Dunn's office MEETING MINUTES Ron Straka opened the meeting and defined the purpose of the meeting. Ron identified what topics were going to be covered. Topics to be covered in this first meeting included: • the project history • goals and objectives • site conditions • alternative site designs under consideration • overall permitting issues, and • establishing a process and commitment for development of an agreement with the agencies to implement the mitigation bank Ron asked that each person introduce them self and state their responsibilities. Ron stated that the City recognizes that each agency staff who will be working on this project needs to work within their regulatory framework and that the City is not asking for MAY-lb-94 SUN 15:41 PARAMETRIX FAX NO, 206 889 8808 P, 03/06 to: Files from; Tracey McKenzie May 15, 1994 Page 3 special consideration. However, the City does ask that agency staff support and make a commitment to work positively toward the completion of a Memorandum of Agreement (MOA) (or surrogate for an MOA) that could serve as a model for other communities, and work together cooperatively wok• Ron then provided a brief project background that covered the following: • City adopted ordinance in 1992 that regulates activities in wetlands in response to the Growth Management Act (GMA.) asW__C� and Glacier -Park -o7f`•pareels of laff4j, City would allow the filling of up to ewe • acre of low quality wetland on 6 different parcels,(under--a-Nationwide 26- ermit from the Corps) for a-�atal-e£up to 6 acres. p rimer p Currently, 4.18 acres of wetlands have been filled under t#e vaue Nationwide 26 permits i r • � lacier Park tpwparcels (Mitigation Banking Site 1 and 2).to the City of Renton �- Use s A .,Je (q_) ', 9---the wetland mitigation bank parcels-brave already been identified-and occur within ""the Black River drainage Would lertele Aryl, • ( G1044S wA^ 40 providWmitigation or fills aloe u er r6 GCME d _ the s• �v J�Get�bkh�lC SI'CS N�/l� �e ur,B� t offset of develo� 4: in >ne force Ire L • City has invested significa t resour es in the baA and is commit d to arts implementation; • the City has adopted a comprehensive plan in compliance with growth management standards that seeks to protect, and if possible, enhance natural resources, Scott Woodbury presented the goals, objectives, and policies of the project (refer to the goals, objectives, and policy handout) and indicated that: • the City's mitigation bank program is to be consistent with the agreement between the City and Glacier Park, the City's wetland ordinance, and the Comprehensive Plan; • the mitigation banking program should clarify and help streamline the permit and mitigation process MAY-15-94 SUN 15:42 PARAMETRIX FAX NO. 206 889 8808 P, 04/06 to: Files from: Tracey McKenzie May 15, 1994 Page 4 • the intent is to implement the policy of no net loss of wetland resources in a manner that optimizes the ecological benefits while providing a creative solution for promoting controlled economic growth in compliance with the requirements of the GMA. k Phil Schneider asked is the program would apply to only public projects, or to both public and private projects. Response: Currently, the program is intended for both public and private projects. Scott indicated that the City would like to be under construction by next summer (on Mitigation Banking Site 2) and that we need to map a path from now to then. Scott provided a review of the hydrologic information about the sites and project area (entire drainage basin). There is a lot of information on the watershe V01d Uhyd hydrology. and wetland resources within the watershed. The City has been developing ydrologtc 5HP3 hrdpubf-(Iiodels for the watershed under current conditions and future development scenarios. -T� are`16--square-miles of tributary area associated with Mitigation Banking Site-1--Springbrook Creek has a long history of channelization and has poor water quality:—Water from the crsentets-into the Green River forebay. AC 4hc. Pram'. r,. - Tracey McKenzie gave a brief overview of the existing conditions (i.e., soils, vegetation, hydrology, proximity to other habitats/wetlands) of 4," Mitigation Banking sites. Refer to handouts from meeting. v{tP4;4� fGc�,y�r The remainder of the��.n tiny was sent di��eussing a process for OA - the agenciestarid`tit�her sues. pci£ically, the issue ass��th 1��OA development ,ix is as follows; �ssucs �Jcu.sr MOA, Dgvelgpment- �, Q �Y +�r� Q.,� �, i�uat _ r• i'1p� If the City wants an MO ,with the agencies, the Corps would likely become the lead agency and the City would direr control over the„� t -Under the MOA scena io, an .. tt, �PH,;t) 4, e-v C yl,,:.FRi.,r C1 •, interagency team would end u� d�ec ding yw ten ro,;e are eligible to use the mitigation bank-.V ten ive to-e r'M6 a is a mi.ti atio agreement as part of the •1/ �� n �nti 43* Ie 404 process and permit needed for�tlie saes. n�er t1ii s nai i ,'i e y could have same n�.rc ti� Mai,., control ove�r�use of the bank. The agencies would the mitigation sites as projects 4x2im ely s through the 404 rocess, but that would not guarantee that �,�uM �MA 1:rfr C n,o+cn�,a( uses will ma- it through th process and be eligible for using the mitigation ��. --A-thir"ltetnative that was identified was to develop a hybrid agre , that--would-be between the MOA process and mitigation agreement per Section 404.--TIte MAY-lb-94 SUN 15:42 PARAMETRIX FAX N0, 206 889 8808 P, 05/06 to: Files from: Tracey McKenzie May 15, 1994 Page 5 City indicated that they want to manage the-bank. Thus, under this third-scenario it-may be possible for the City to manage the bank for projects that impact less than 1 acre of above the head waters or isolated wetlands (mitigation has typically not been required by the-state and federal agencies); projects that impact greater l an one-atrewculd require consultation with an interagency cornmittee'Conclusion: the City needs to decide how they want to have the program structured and what type of agreement they want. MOA would need to be agreed to and signed by Corps headquarters. (Any There is a draft National Polity of Mitigation Banking being reviewed by the federal d, agencies. It is possible that if the City elected to have an MOA with the agencies and the National Policy is issued, the project would be subject to the provisions and requirements of the National Policy. s Irrespective of whether the City decides to develop a formal MOA with the agencies or a mitigation agreement as part of the 404 permit process, the WSDOT MOA shel td be used as a model. � f� Other issues/items identified and brigfly_discussed: —� 974, • Ben Meyer indicated that the City3�need to mitigate for impacts to any existing wetlands on the site that would be affected by the restoration/creation action to establish mitigation banks. �o 1411 • Ron Straka indicated that the demand for r op f sites is high. He knew of 6 sites in high demand as well as other parcels. Currently, the going rate is about $4.00 to 5.00 per foot of developable land. �'� Eric Stockdale indicatedl�airs important to not just focus on losing somgWnd acreage that developed on fill. We need to look at the project from a landscape and watershed perspective and consider what is being put back that was historically lost. Also we need to consider the additional functions that can be gained by this action. • We should not get caught up in the number game when it comes to looking at impacts, losses and gains. Again, keep in mind the existing functions and functions to be gained. IIIyv -rlr 6oli e,- v/- r/c6 v�.r H- i.^� ' e;" �i' g /� � � ��'� -/J�c r Lo3 S 0 The Corps indicated that when they go out for public notice they will want to include information on the existing functions and the functions proposed. The City will need to decide on a methodology that will provide this type of information. Tracey asked MAY-15-94 SUN 15,43 PARAME`I'RIX FAX NO, 206 889 8808 P. 06/06 to; Files from: Tracey McKenzie May 15, 1994 Page b it ,'qi the agencies had a particular preference for a method. Everyone agreed that there are several available;fliere is nd'one particular agreed-to method, and that we (the City and the consult peed to identify what method we are going to use. We responded that `has a 4 ut we did no wan��to gt into�arsituation where we use one method an comments come back ��b�ic- erse saying we should have used another method. The City and their consultant will discuss which method or combination of methods would be suitable for these sites. A standardized form sad be developed for whicli"ever method or combination of methods is used so that it i&a cable now and 5'years from now. Tracey went over the three overheads (also a handout) that described the federal, state, and local permits that may be needed for the project. In general, she asked the federal and state agency representatives if all the potential federal and state permits were identified and correct. Eric Stockdale, Ecology, needs to check on whether a water rights permit is necessary and about a dam safety permit. The agencies recommended that the City inN,0 +e the Muckleshoot Indian tribe, The meeting was brought to a close and the City indicated that agency staff will be contacted at least 3 weeks in advance of the second agency meeting. � � f MEETING ATTENDANCE RECORD w C1LAn)o k1117-1 6Arjoa dAtJk /lZo&R4.j,,. SUBJECT Ury OF REWOM DATE 5/2-/9y LOCATION C 011-W IM Iry C " , Af NruM ,LAJA THOSE IN ATTENDANCE NAME ADDRESS PHONE VAG bO W) Cv, afj 6/ )0-7 c�. :bwn)5 NRts Ln SG ,Sut}e, iC) _ 753 N9b 11'�'�J✓� ,�. Dig -5-0 3 Z 3 0, ,(z PM x lroic2 MG V1ZlQ 5$0S La vc� . dD b g - D Ete r STC)c�-1 Lc- 3.qo c6G 6 u�35 FOWNIAL WY waffle q-4qlq.3 G 1 76 7f- 3ggJ I-Epi S *65-5, 217 SS�� Us �ep ,. Pvxx s-v 5Z r T}iE CITY OF RENTON -- -------_-- DEPARTMENT OI �.::� PLANNING/BUILDING/PUBLIC WORKS `t FOURTH FLOOR 200 MILL AVENUE SOUTH ! 15—vol RENTON, WASHINGTON 98055.2189 1 r FAX: 235-2541 FAX TRANSMITTAL DATE: b/f f TO: 'MA Cary A,K� E FAX#: FROM: SCE W0006UI� PHONE#: 277- 55`f7 t/4-rLA'o M/P6.0-g4 &NOA PAGQAAI SUBJECT: AITP,*,A.,jci Lsr Pat 5/40 A 6dx4 Numbcr of P:igcS cxcluding cover sliccu 1/I of Hl:/N L.t/I A X(.OVf,( ,)()(/1,1 ° TALAS AEA LETTER OF CONSULTANTS TRANSMITTAL Resource & Environmental Planning 118-162nd Avenue Southeast a Bellevue,Washington 99008 Bus(206)641-4710 Fax(206)641-4700 To: Date: ' Subject: RO= Lt ► 1 Y1_ �1.�� P 1b Project Number: 11�-A Attn: 3(4k lkkM w" From:11 Transmitting Herewith: The Following: For: Proposal Review & Comment Contract Approval No. of Copies Change Order Signature Sets Letter Your Use & Files Sheets Re ort Payment Orints or Drawings As Requested Specifications Action Noted Below Other Description of Materials: FJOMMIALZQ I CE CC P16e✓V9 "LPpy h F Lt t I(A), E z1u ki V'Y)OuAlca OYl fw-vyl r I YI-M Remarks/Actions: Si cerely You , IAtASA' Consultants Copy To: 6 CITY OF RENTON =LL Planning/Building/Public Works Department Earl Clymer, Mayor February 11, 1994 Tracey P. McKenzie, Project Manager Parametrix, Inc 5808 Lake Washington Blvd. N.E. Kirkland, WA 98033-7350 SUBJECT: WETLAND MITIGATION BANK PLAN PROJECT SUMMARY OF JANUARY 31, 1994 MEETING WITH THE CORPS OF ENGINEERS Dear Tracey: As we discussed in our recent phone conversation, I have included following a summary of the January 31, 1994 meeting with the Corps of Engineers. Please call me to discuss the conclusions that may be drawn from the meeting. SUMMARY OF JANUARY 31, 1994 MEETING WITH THE CORPS The meeting opened with Ron Straka of the City Surface Water Utility presenting an overview of the project history and current status. Corps staff attending the meeting included Tom Mueller and all representatives responsible for adjacency determinations, as well as Gail Terzi, the Corps staff assigned to the wetland bank project. The attendance list is included as Exhibit B. Following the project overview, Ron Straka opened the adjacency discussion by presenting additional information not considered in the Corps adjacency determination document Memorandum for Record (MFR) received by the City in November 1993. It was pointed out that the MFR findings concerning the wetlands at the bank sites do not reflect that 98% of site 1 and 100% of site 2 are above the 100-year floodplain, and that the MFR findings for site 2 contradicts a 1992 Corps non-adjacency ruling regarding a portion of the wetlands on site 2. The response of the Corps may be summarized into the following main points.- 1. The Corps will not reconsider the adjacency ruling on the wetland mitigation bank sites. Surface hydrology to Springbrook Creek was deemed to be irrelevant. Other issues were noted to be of more importance to the Corps, such as wetland evaluation methods, performance standards, wetland compensation credit withdrawal procedures, and other bank operation issues. 2. The Corps did a poor job of determining adjacency in the past and would not make the same ruling for previous determinations if made today. Although determinations are made on a case-by-case basis only, the Corps speculated that most, if not all, of the valley would be ruled adjacent based upon currently used criteria. 3. The Corps published criteria for determining adjacency is very broad and vague (Exhibit C). In an effort to facilitate consistent determinations, the Corps Seattle branch uses a supplemental, multi- parameter checklist. However, the checklist is for internal use only and is not available to the public. 200 Mill Avenue South - Renton, Washington 98055 THIC PAPER U(WFAI v�%O7 -fi - i - . "' 11_. r Tracey P. McKenzie Parametric, Inc. February 11, 1994 Page 2 4. The Corps permitting authority is expected to change within a year in a way that will do away with adjacency rulings. The following comparison table illustrates the changes regarding thresholds for impacting wetlands. Current Thresholds Proposed Thresholds Regional Permit 0.0 - 1.0 acres. Isolated 0.0 - 0.5 acres for any wetland. (Nationwide) wetlands only. Regional Permit With 1.0 - 2.0 acres. Isolated 0.5- 3.0 acres for any wetland. Predischarge Notification wetlands only. Individual Permit Over 2.0 acres for isolated Over 3.0 acres for any (Requires alternatives wetlands. wetland. analysis) Over 0.0 acres for adjacent wetlands below the headwaters. 5. Any impacts to existing wetlands on the wetland mitigation bank sites will require a 404 individual permit. An August 23, 1993 Regulatory Guidance Letter and an October 25, 1993 Draft Mitigation Banking Guidance Document will be used by the Corps to formulate the individual permit conditions. The Corps recommended initiating, as soon as possible, the process of developing a multi-agency agreement regarding the wetland mitigation bank. The agreement would spell out mitigation and specifically what can and can't be done in the use of the sites as compensation for other wetland impacts. The Corps indicated that the bank sites could be used as compensation for multi-acre wetland impacts due to a single project, although the Corps would prefer compensation for many separate and smaller impacts. 6. The Corps 404 individual permit process requires evaluation of alternatives. In general, on-site mitigation is favored over off-site mitigation. 7. The Corps generally supports the mitigation banking program, but foresees many hurdles and a year- long process in obtaining a final inter-agency agreement. A copy of an agreement between the Washington State Department of Transportation and wetland resource agencies that is pending execution was provided. The agreement was noted as a potential model for a similar agreement between the City and wetland resources agencies for the City wetland mitigation bank project. CONCLUSION The following conclusions may be drawn from the above summary of the January 31, 1994 meeting with the Army Corps of Engineers: 1. The Corps is much more proactive in making wetland adjacency rulings than they were even a year ago. Impacting an adjacent wetland, no matter what the size, requires an Army Corps 404 Individual Permit. This could have a profound impact on development in the valley, since the Corps stated the opinion that most wetlands in the valley are adjacent. 2. By being inflexible on the adjacency issue, the Corps maintains control over the development of the City wetland mitigation bank through the individual permit process. In order to create a functioning wetland system on the mitigation bank sites, some impact to the existing wetlands will be necessary, triggering the 404 individual permit process. Although it is anticipated that this would not prevent Tracey P. McKenzie Parametric, Inc. February 11, 1994 Page 3 development of the wetland mitigation bank, it could alter the scope of the bank and add to the time and cost of implementation. Potential changes include: a. Compensation ratios greater than that required by the City Wetland Management Ordinance. b. Evaluation of wetland functions and values using a complex method, such as Wetland Evaluation Technical (WET), that is not required by the City Wetland Management Ordinance. c. Permitting, operation, performance, and maintenance requirements greater than that established by the City Wetland Management Ordinance. d. Limiting the amount of compensation credits available to be withdrawn until a minimum time period has passed. 3. There is no longer any reason for the Corps to withhold formal issuance of the bank sites MFR. The Corps has yet to formally issue the MFR, as requested earlier by the City to allow the City more opportunity to review the issue. 4. The City may choose to legally challenge the Corps adjacency determination. It is likely that a challenge would receive the support of neighboring municipalities and others with land interests in the valley. However, significant resources may be expended to reach a decision favorable to the City, only to have the adjacency issue no longer be a factor because of changes in regulations. The nearness of pending regulation changes alone may make formulating any challenge useless because of the time needed for initiating such a challenge. The vagueness of the Corps published criteria and the Corps' proprietary claims of their in-house checklist would also make formulation of a definitive legal challenge difficult. 5. Under current regulation, the authority of requiring compensatory mitigation lies solely with the City Wetlands Management Ordinance for impacts up to the 1 acre threshold of the Corps regional permit. Until there is a change in Corps regulation, issuance of new regional permits in the valley, such as nationwide 26, is unlikely at this time, given that the Corps has said that most, if not all, wetlands in the valley would be ruled adjacent. If no developers are willing to risk the Corps 404 individual permit process, then the potential users of the bank are limited to those with existing regional permits, or to those who are able to secure a new regional permit despite what the Corps has said. 6. The Corps jurisdiction is determined case-by-case for regional and individual permits. Pursuing a multi-agency agreement would better define the base of potentially qualifying users of the bank. Additionally, the developer may give increased consideration to using the bank if the support of the Corps and other wetland resource agencies is formally contained in an executed agreement. Formulation of a draft mitigation agreement is within the current scope of the City wetland bank consultant contract. 7. It is anticipated that the City will need to obtain a 404 individual permit for the wetland mitigation bank project regardless of whether or not the wetland mitigation bank site wetlands are determined to be adjacent. Even if the wetlands were not determined to be adjacent, it is anticipated that the preferred alternative wetland creation/restoration plans for the mitigation bank sites will likely either require impact to the existing wetlands of greater than one acre and trigger the 404 regional permit pre- discharge notification process, or require impact to the existing wetlands of greater than two acres and require a 404 individual permit from the Corps. Tracey P. McKenzie Parametric, Inc. February 11, 1994 Page 4 Because of the requirement to satisfy City's obligations agreed to in the Glacier Park Agreement and the City Wetland Management Ordinance, we will continue with the preparation of the Wetland Mitigation Bank Plan. As we will likely need a 404 individual permit for construction on the project sites, the Corps may make formation of a memorandum of agreement with the agencies a condition of the permit, unless we limit users of the bank only to donor projects with wetland impacts authorized under a Corps regional permit. Please call me to discuss this issue. I will compile comments on Chapters 1-6 of the Wetland Mitigation Bank Plan and transmit them to you as soon as possible. I will also proceed with arrangement of the agency and public meetings for sometime in mid-March 1994. As advised by Eric Stockdale of WDOE, we need at least a one-month lead to ensure that the agency representatives are able to attend. Please let me know what dates would work with you. As you had requested, I have also enclosed a copy of the January 4, 1994 Washington State Department of Transportation Wetland Compensation Agreement. If you have any questions, please call me at 206- 277-5547. Sincerely, Scott Woodbury, Project rylanager Surface Water Utility H:UTIL/S W/W TIr PRM/S S W:lf Attachment cc: Ron Straka Jr 1 {I .I AY IONlY16 f �, '�".)/. � b U ux �.�Ya111.Y►0 � _.t; f �-_� '�,A71ryA A G IF - � II e T Ir G II G ~'.tAr rnarnoa -•--I��~ihoT-r o"_' -.. I ,•,__rt IOS)OYr II --_ == = - -- - -- - • I1, i_/,/-//,'// _ , I s Federal Register / Vol. 51, No. 219 / Thursday, Novemfx:r 1,s. I" / Rules and Regulations 41251 (b) The term "wetlands" means those (b) Tidal Waters of the United States. 5� areas that are inundated or saturated by The landward limits of jurisdiction in 329.11 Geographic and juri5dictiunal limits tidal waters: of riven and lakes. surface or ground water at a frequency 329.12 Geographic and jurisdictional limits ,uid duration sufficient to support. and (1) Extends to the high tide line. or of oceanic and tidal.waters that under normal circumstances do (2) When adjacent non-tidal waters of 329.13 Geogrephic limits:shifting "Of,l,ort, a prevalence of vegetation the United States are present• the boundanes i5 pically adapted for life in saturated Jurisdiction extends to the limits 329.14 Determination of navigeh'itty act, conditions. Wetlands generally identified in paragraph (c) of this 329.15 Inquiries regarding determinations include swamps, marshes, bogs. and ction. 329.1e Use end maintenance of lists of similar areas. (c)Non-Tidal Waters of the United determinations. c e term "adjacent" means totes. The limits of jurisdiction in non- Authority:33 U-S.C. .a"i et seq bordering,contiguous,or neighboring. idal waters: §349.1 purpQu_ Wetlands separated from other waters (1) In the absence of adjacent of the United States by man-made dikes wetlands, the jurisdiction extends to the This regulation defines the term or barriers. natural river berms,beach ordinary high water mark,or "navigable waters of the United States- as and the like are "adjacent as it is used to define authorities of the (2)When adjacent wetlands are Corps of Engineers. It also prescribes wetlands." resent, the jurisdiction extends beyond arm i tide line"means y the policy,practice and procedure to be g e ordinary high water mark to the limit used in determining the extent of the the line of intersection of the land with of the adjacent wetlands. jurisdiction of the Corps of Engineers the water's surface at the maximum (3)When the water of the United and in answering inquiries concerning height reached by a rising tide.The high States consists only of wetlands the I.navi8able waters of the United States." tide line may be determined in the jurisdiction extends to the limit of the This definition does not apply to absence of actual data,by a line of oil or wetland- authorities under the Clean Water Act scum along shore objects,a more or less which definitions are described under 33 continuous deposit of fine shell or debris 9 328-6 ChanQ"In Hsntts of waters of ttie CFR parts 323 and 328. on the foreshore or berm,other physical United States. markings or characteristics,vegetation permanent changes of the shoreline §329.2 Appt}cablltty. lines. tidal gages, or other suitable configuration result In similar This regulation is applicable to all means that delineate the general height alterations of the boundaries of waters Corps of Engineers distncts and reached by a rising tide.The line of the United States.Gradual changes divisions having civil works encompasses spring high tides and other which are due to natural causes and are responsibilities. high tides that occur with periodic perceptible only over some period of frequency but does not include storm time constitute changes in the bed of a 1329.3 Gw ral poticlea- surges in which there is a departure waterway which also change the prt`cise definitions of"navigable from the normal or predicted reach of boundaries of the waters of the United waters of the United States" or the tide due to the piling up of water States. For example, changing sea levels "navigability" are ultimately dependent against a coast by strong winds such as or subsidence of land may cause some on judicial interpretation and ca<<not be those accompanying a hurricane or areas to become waters of the United made conclusively by administrative other intense storm. States while siltation or a change in agencies.However, the policies and (e)The term"ordinary high water drainage may remove an area from criteria contained in this regulation are mark" means that line on the shore waters of tho United States.Map-made in close conformance with the tests used estdblishad by the fluctuations of water changes may affect the limits of waters by Federal courts and determinations and indicated by physical of the United States; however, made under this regulation are characteristics such as clear, natural permanent changes should not be considered binding in regard to the line impressed on the bank, shelving, pre4uned until the particular activities of the Corps of Engineers. changV in the character of soil. circumstances have been examined and des'ructlon of terrestrial vegetation, the verified by the district engineer. 1329.4 d�r�dafinitlon. presence of litter and debris,or other Verification of changes to the lateral Navigable waters of the United States appropriate means that consider the limits of jurisdiction may be obtained are those waters that are subject to the characteristics of the surrounding areas. from the district engineer. ebb and flow of the tide and/or are (f)The term "tidal waters" means PART 329--DEFINITION OF presently used or have been used in the those waters that rise and fall in a NAVIGABLE WATERS OF THE UNITED past, or may be susceptible in,- use to predictable and measurable rhythm or STATES transport interstate or foreign cycle due to the gravitational pulls of commerce. A determination of the -noon and sun.Tidal waters end Sec. navigability, once made• applier vvht re the rise and fall of the water 329.1 Purpose. laterally over the entire surface of the surface can no longer be practically 329.2 Applicability. waterbody, and is not extinguished by measured in a predictable rhythm due to 329.3 General policies. later actions or events which impede or making by hydrologic.wind. or other 32A.4 Goneral deftnitioru. destroy navigable capacity. effects. 329.5 General scope of determination. 329.9 Interstate or foreign commerce. §329.5 Omani trope of determinstion. ;1 328.4 Umits of lurisdtcttor, 3297 intrastate or interstate nature of The several factors which must be waterway. examined when making a determination 1,) Territorial Seas. The limit of 329.8 improved or natural conditions of the jurisdiction in the ter-itorial seas is waterbody whether a waterbody is a navigable measured from the baseline in a 329.9 Time at tehkh commerce exists or hater of the United States are discusse•- seaward direction e distance of three date nin stars is m9de. ir detail be''iow. Generally, the foilcv+ing cond €etiefied n;t_;!iral miles (See 33 CfR o 32912j 329.1 E:;r!dn•� n± obetrurtion: itions -,._t be TEL Jan 01 >01 3 :22 PIo .002 P .01 TALASA EA CONSULTANTS PRO.IECT:` LPL FACSIMILE TRANSMISSION FORM I IA"I F: ! TIME-Z ....._ ._..._... TOTAL NUMBER OF PAGES (INCLUDING HEADER): � RECEIVER NAME:0r V&,J�- FIRM: dy FAX NUMBER: 15�� SENDER NAMEN (X�f _.._.......,. FAX NUMBER: (206) 641-4700 REMARKS CDt Iry1' 2t�f1LCM�T� ►t ._L4 ' Please contact us at (206) G41-4710 if there is a problcir roceiving this FAX. r2.:suurcc `a? I .n%,iroIIIItt nt:1l i)I,kitnitti? 118- IG211d AVCMIC Sf'Uthl.'a"I 4 15'r11vv1,'.11',tt',11in,1 :,sUUr v hu:•. (Y(i(t�o ii 'ii It) • Fox t2oo)G,il•Voo ° TALASAEA LETTER OF CONSULTANTS TRANSMITTAL Resource & Environmental Planning 118-162nd Avenue Southeast• Bellevue,Washington 96008 Bus(206)641-4710 Fax(206)641-4700 To: LbT l Date: [-;,Vo• 9q 200 M Subject: P454ToQ MrrTd&nC*--( O" , VJA, a a[r= C OKIc.r-pr Project Number: (mil Attn: 3CZrF ViJ000P)k)2=Y From: �AM04t C)"Vo�_-, Transmitting Herewith: The Following: For: Proposal Review & Comment Contract Approval Change Order Signature No. of Copies: Sets - Letter X Your Use &fps Sheets Report Payment Prints or rawinn s As Requested Specificatio— Action Noted Below Other Description of Materials: NIDIF-IffJ2 CXZOI uWE M, W1w 4(41b •oWo mot-4 Lr SrtF- 1 -4 2 Ax�j o i coN�Pr `o A fulid FOP, Si`C ( AND rwo CD"Lrj? ' owa6 r-o ez:> a, Remarks/Actions: ILLLE-, �-e FOP, Lam, ikl )d1 l.;�(- -i Vtrj ►tJiM AS i ereiy Yo -J� , TALASAEA Consultants Copy To: PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT Y O MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 Q UTILITY SYSTEMS DIVISION - 235-2631 NT 0 TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: JOB NO. : RE: ATTN: GENTLEMEN: WE ARE SENDING YOU ❑ ATTACHED o UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: ❑ SHOP DRAWINGS ❑ PRINTS ❑ REPRODUCIBLE PLANS ❑ SPECIFICATIONS ❑ COPY OF LETTER ❑ COPIES DATE NUMBER DESCRIPTION AND REMARKS THESE ARE TRANSMITTED AS CHECKED BELOW: o FOR APPROVAL ❑ APPROVED AS SUBMITTED ❑ RESUBMIT COPIES FOR APPROVAL ❑ FOR YOUR USE ❑ APPROVED AS NOTED ❑ SUBMIT COPIES FOR DISTRIBUTION ❑ AS REQUESTED ❑ RETURNED FOR CORRECTIONS ❑ RETURN CORRECTED PRINTS ❑ FOR REVIEW AND COMMENT ❑ ❑ PRINTS RETURNED AFTER LOAN TO US COPIES TO: SIGNED TITLE IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE ��c A IVGE cr- NOV ✓/ ��#3 0f�h Fj- w/ NO C01K WIAX ' �-�� s'tSG'l0�s • w1 T� %ar,nnt.-4'S LIST OF TABLES Table Page 1 Inventoried wetlands within the Black River Drainage Basin . . . . . . . . . . . . . . . . . . 14 2 Recommended preference for allowing impacts to be compensated for at the mitigation bankingsites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3 Regulatory requirements needed to implement the Mitigation Banking Program . . . . . 33 4 Anticipated changes in land use in acres 5 Approximate acreage of wetlands in the Black River Drainage Basin . . . . . . . . . . . . 67 LIST OF FIGURES Figure Page 1 City of Renton Inventoried Wetlands and Streams 2 Natural Wetlands Prior to Valley Development 3 Approximate Extent of Filling in the Valley from 1975 to 1987 . . . . . 4 Mitigation Banking Sites 1 and 2 . . . . 5 Flow Chart to Determine Eligibility for Use of Mitigation Banking Program . . . . . . . 29 6 Black River Drainage Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Valley Drainage Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Existing Conditions Mitigation Banking Site 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Existing Conditions Mitigation Banking Site 2 , . . . . . . . . 10 Soil Test Location Characteristics of Mitigation Banking Site 1 . . . . . . . . . . . . . . . . 11 Soil Test Location Characteristics of Mitigation Banking Site 2 . . . . . . . . . . . . . . . . . . . . . . . . . 48 12 Types of Mitigation Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parametrix, Inc. 55-1779-07 iv City of Renton -DRAFT drftmtigpin November 11, 1993 EXECUTIVE SUMMARY TO BE COMPLETED LAST Parametriz, Inc. v City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Provide incentives for overall net gain of wetland functions and values for new development (EN-6.7, Comprehensive Plan). • Establish and protect buffers along wetlands to facilitate infiltration and maintain stable water temperatures, provide for the biological regime, reduce the volume and velocity of runoff, and provide for wildlife habitat (EN-6.2, Comprehensive Plan). • Encourage preservation and enlargement of existing habitat areas through development incentives (EN-14.3, Comprehensive Plan). • Increase the community's understanding of the City's ecosystem and the relationship of the ecosystem to water resources (EN-11.2, Comprehensive Plan). • Encourage public access to wetlands for use when sensitive habitats are protected(EN-6.8, Comprehensive Plan). • Where appropriate, combine all critical areas and environmentally sensitive areas with recreational facilities to provide public access and trail linkages through separators (EN- 15.7, Comprehensive Plan). Parametrix, Inc. 9 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin Table 3. Regulatory requirements needed to implement the Mitigation Banking Program. Statutes/ -T Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" Federal Compliance with Required for dredge U.S. Army Corps of Clean Water Act, (1)Nationwide permit Section 404 permits Section 404 and fill activities in Engineers (Corps); §404;33 USC§ 26,<1 acre:4-6 weeks; AND Nationwide waters of the U.S. Seattle District Office 1344;33 CFR (2)Nationwide 26,>1 permits are typically including wetlands. 320 et seq.;40 acre: 8 weeks valid for a 3-year CFR Pt 230. minimum;(3) period, but may be Nationwide 27:6-8 extended through weeks;(4)Individual negotiated permit permit:22-week conditions. minimum. NEPA process must be completed before permit can be issued. All federal permits or Corps will be the lead 42 USC§4321 et Issuance of final EIS or NEPA review(EA or National approvals issued for agency responsible for seq., 40 CFR Pt EA must precede EIS) must be revisited Environmental construction or NEPA compliance, and 1500 et seq.; 10 issuance of any federal only if there are(I) Policy Act(NEPA) operation of the facility compliance will be CFR 1021 (NEPA permits;usually,30 "substantial changes in trigger NEPA done through the regulations) days must elapse after the proposed action"or procedures;NEPA Section 404 process. issuance before federal (II)"significant new processes must be agency can issue the circumstances or complete before any underlying permit. information"relevant federal permits can be to environmental issued. concerns. Threatened or Not a separate process; Department of the Endangered An endangered species Varies Endangered Species instead,requirements Interior through U.S. Species Act, 16 survey would take Assessments will be incorporated(if Fish and Wildlife USC§ 1531 et varying amounts of applicable)into the Service w/assistance seq.; 50 CFR Pt time depending on site Section 404 permit from local jurisdiction 402 conditions. A process or Nationwide and State of Biological Assessment permit process. Washington Dept of takes up to 180 days,or Wildlife. Department more. ESA § 7(c). A of Commerce through Biological Opinion, if the National Marine needed, takes 45 days. Fisheries Service. 50 DFR§40214(e). Historic Preservation Compliance must be Corps will be primarily Natural Historic Timing depends greatly N/A;this review Review assured through the responsible for Preservation Act, on the resources would be a component Section 404 or compliance. It must § 106, 16 USC§ affected, if any, and the of other permit Nationwide Permit take into account 470 et seq.;36 presence of opposition processes. process. comments of the U.S. CFR. §§ 60-63, and likelihood of Advisory Council on 800; 16 USC§ appeal. Historic Preservation if 469 et seq. a protected property or Not critical path. site is identified. Parametrix, Inc. 33 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shel7Life State of Washington State Environmental All state and local Probable SEPA lead Specific to each SEPA review must As with NEPA, Policy Act(SEPA) permits or approvals agency: City of Renton City/County. precede the issuance of supplemental issued for construction any state or local environmental review or operation of the permits or approvals by is required only if facility must comply 7 days. An EIS and there are(I) with the procedural associated studies "substantial changes to requirements of SEPA. generally take at least a proposal so that the A DNS, MNDS, notice 10 months to 1 year to proposal is likely to of adoption, or final complete, assuming no have significant EIS must be issued appeals. If SEPA adverse environmental before agencies issue review is "adopted," the impacts"or(1I) "new permits or approvals. process can be information indicating completed in about 1 a proposal's probable month after the significant adverse completion of the environmental impacts. SEPA process. Hydraulic Project An HPA may be Washington Ch. 75.20 RCW; HPA application must Permits must Approval(HPA) required if project Department of Fisheries Ch,220-110 be processed within 45 demonstrate crosses/affects fresh WAC calendar days of the "substantial progress water streams. submission of a on construction on that complete application portion of the project and after issuance of a relating to hydraulic final EIS. No public approval within 2 hearing required. years of the date of issuance." HPA approvals may be granted for a period of up to 5 years. Temporary Required for Washington Dept. of Ch. 90.48 RCW; Generally, temporary None established by Modification of Water construction activities Ecology (Ecology), WAC 173-201 water quality regulation;permit Quality Criteria that temporarily violate Northwest Regional and 173-222, modification must be terms and conditions water quality criteria. Office. sought 30 days prior to generally cover May be required for any in-water work. duration of work stream diversion requiring the structures. modification. Water Quality Required of any Ecology Headquarters; Federal Clean Timing of certification Not Applicable Certification(§ 401) applicant for a federal Central Programs; Water Act, varies. license or permit to Environmental Review Section 401;Ch. conduct any activity Section, Olympia. 173-225 WAC that may result in any discharge to surface waters. CZMP Consistency Required for permits Ecology, Shorelines 16 USC§1451 et Certification can Not applicable. Certification and licenses affecting Program,Olympia. seq.; 15 CFR generally be obtained in shoreline areas and is parts 923-930 60 days. usually considered during the Section 404 or Nationwide permit process. National Pollution Storm water pollution Ecology, Industrial Federal Clean Generally, 30 days Generally, covers Discharge Elimination control for construction Storm Water Unit. Water Act S 402; following receipt by duration of work. System(NPDES) activity that disturbs 5 40 CFR parts Ecology of Notice of Permit or more acres. 122-124 RCW Intent 90.48, 90-52; WAC 173-220 Parametrix, Inc. 34 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 1 2 3 SURFACE 18 SURFACE ELEVATION 2 ,.s, r,...... 16 s> -4 14 w -6 12 � , z a 0 8 10 -10 8 -12 6 -14 4 Sandy Silty Fill Silty Sand with Mottles and Fill Figure 10. Fine Silty Sander Seepage Soil Test Location Characteristics ® Iron Oxide Layer Wood Debris of Mitigation Banking Site 1 implemented by individual permit applicants (Riddle 1986), because of the long-term involvement, commitment, and experience of resource agencies. • Public recognition of wetland mitigation efforts associated with establishing a mitigation banking program can provide increased incentive for developers to participate in banking efforts (Ford 1991). • A mitigation banking program puts the mitigation up front in the planning and permitting process (Short 1988) and can improve the efficiency and effectiveness of wetlands regulation through added regulatory flexibility. When incorporated as part of a program involving public and private parties, mitigation banking can help reduce future conflicts. • Mitigation banking can consolidate the mitigation needs of numerous small projects up front and can provide larger, ecologically sound and viable compensatory mitigation than individual small mitigation attempts. • Thoughtfully conceived and properly implemented mitigation banking programs may provide better overall mitigation results by minimizing the uncertainty of the mitigation success, and by eliminating the time lag between loss of wildlife habitat and other functions at the development site and compensation for those losses (Riddle 1988; Ford 1991). • Large-scale mitigation banking projects may be more economical to develop and manage than small mitigation projects. Larger blocks of habitat may result in more benefit in terms of wetland values per dollar spent than is possible when smaller areas are involved. • The mitigation banking program can provide the opportunity to consolidate financial and management resources of public and private entities to support mitigation actions that might not be financially feasible for individual applicants pursuing off-site mitigation. • A fee structure could be established that would (1) allow a project proponent to pay a one-time fee to the City to cover a proportion of construction, maintenance, monitoring, and management costs of the wetland mitigation banking program, (2) simplify the permit process, and (3) provide funds to create large mitigation areas that may be more ecologically valuable and more easily monitored and maintained than smaller mitigation projects. The fee structure needs to be based on several parameters (e.g., construction costs, administrative time and costs, monitoring,maintenance, etc). The project proponent would pay one "impact" fee to the City and a portion of the fee could be placed into an accumulating fund that would be used to restore, monitor, and maintain wetlands at the mitigation banking sites. A more detailed discussion of scenarios for fee and payments is discussed in Chapter 7. Programmatic Mitigation Plan. Parametric, Inc. 71 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin Although the City may need to carry the burden of up-front costs, there would be additional acreage available that one or more project proponents could use to compensate for separate project impacts. Additional available upland acreage could be used to initiate the City of Renton wetland Mitigation banking program. The money received for these banked credits could then be used to help finance additional restoration activities at the other mitigation banking site. This would ensure that the City always has some money in the bank to use to restore additional uplands on the other mitigation banking site, and wetland credits in the bank that can be sold to finance additional restoration. A mitigation banking program in the City of Renton can be effective in balancing economic development needs with protection and conservation of natural resources in an area where wetland development will occur within the next 5 to 10 years. Parametriz, Inc. 73 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmag.pin CHAPTER 7. PUBLIC INVOLVEMENT BEING COMPLETED FOR CITY REVIEW Parametrix, Inc. 74 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin CHAPTER 8. PROGRAMMATIC MITIGATION PLAN BEING COMPLETED FOR CITY REVIEW Parametrix, Inc. 75 City of Renton -DRAFT 55-1779-07 November 11, 1993 &ftmtig pin CHAPTER 9. TECHNICAL MITIGATION PLAN BEING COMPLETED FOR CITY REVIEW Parametrix, Inc. 76 City of Renton -DRAFT 55-1779-07 November 11, 1993 &ftmtig.pin APPENDIX A CITY OF RENTON WETLAND MANAGEMENT ORDINANCE APPENDIX B PHOTOGRAPHS OF SOIL TEST LOCATIONS ON MITIGATION BANKING SITE 2 PHOTOGRAPHS OF MITIGATION BANKING SITE 1 DID NOT TURN OUT N CCD O ,0 to O cC UO U) J O W N H t O 71 WA 4 ` r r y i I y ,F •1" x , _ _ 1 3 pIr I. Test Location 3 a s w1k Test Location 4 Photographs of Soil Test Locations on Mitigation Banking Site 2 (Cont.) .4.v }N t•_ tt ' a i Test Location 5 Photographs of Soil Test Locations on Mitigation Banking Site 2 (Cont.) APPENDIX C LETTER FROM PARAMETRIX, INC. TO THE CITY OF RENTON IDENTIFYING ADDITIONAL INFORMATION NEEDS FOR MITIGATION BANKING SITE 1 harametrix, Inc. Cons;nfanrs in Engineering ardEnwronmentaiSc:ence 5808 Lake Nashing;on Blvd. N.E. Kirkland. WA 98033-7350 206-822-8880•Fax:206-889-8808 0 Mr. Ronald Straka November 4, 1993 City of Renton 55-1779-07 200 Mill Avenue South Renton, Washington 98055 Dear Mr. Straka: Subject: Additional Information Needs for Mitigation Banking Site 1 As we discussed during the Monday, October 18, 1993 meeting, the level of information available for Mitigation Banking Site 1 is inadequate to prepare a detailed site plan. The City requested that we submit a letter indicating the type of information needed before a site plan can be prepared. Below is a list of data and information needs for your consideration: Information Need Timing Survey property boundaries late.fall, winter 1993 Survey P-1 channel easement late fall, winter 1993 Elevation survey of site at 0.5-ft contours' late fall, winter 1993 (including the ditch along western and northern boundary of the site). Have the surveys also map the utilities (especially electrical) right-of-ways, and easements.' Monitor groundwater (see attached map for install and monitor fall, suggested locations) winter, 1993 and spring, summer 1994 Install temporary V-notch weir to measure install late fall 1993,monitor weekly flow in ditch in southwest corner of site through winter 1993/1994,spring and summer 1994 .-ft contours are suggested because the site is relatively flat. 2 77tis information is needed to determine appropriate locations for a potential parking area for public access/educational opportunities. L� Mr. Ronald Straka City of Renton November 4, 1993 Page 2 Identify where the water comes from that enters late fall, winter 1993 into the ditch along the western and northern border of the site. If possible determine the quality of the water. Please call me at (206) 822-8880 if you have any questions regarding this letter or need more information. Sincerely, PARAMETRM INC. Tracey P. McKenzie cc: project file Scott Woodbury I I 18 W 13C HIGH FLOW DIVERSION : CHANNEL IMPROVEMENT 16 - Upland endow an shr land co munity WETLAND M: : 1 }"$ Young, forested, shrub, and , emergent wetland nd communtity WETLAND M A r . W - 22 20 W 2 : ® • : W - 2 WETLAND L. WETLAND J: Shrub communit Y Shrub community i Upland meadow and shrubland community � . 1N - 45 l - -<Ir tic" - - - wmw W - 14 Emu SW 33rd Parametrix, Inc. DRAFT W—Z2 = Wetland code from FIGURE Jones and stokes, 1991 EXISTING CONDITIONS = Mitigation site boundary OSCALE IN FEET O October 19, 1993 SOURCE: CITY OF RENTON, 1993 (D = Soil Test Location (approximate) MITIGATION SITE 1 APPENDIX D ATTENDANCE LIST AND HAND OUTS FROM PUBLIC INVOLVEMENT MEETINGS 1412a/93 City of Renton Wetland Mitigation Bank Project Focus Group Meeting 1 ATTENDANCE SHEET Name Address Zip Phone qC R444u4 ,SGo/r (.JOop L) 200 IMIU- AV6 R AInAJ Uw 9205 - 277-55-917 ZI'7 2 4"7 5 PSI- P-J--WrbA J Fro sS� 1+3 2 ��n� �r�ar' �Z� 2C�/EYe !�E SPo•t�M{L 9�� I� �L(o-O�$ `� T. e ef` 6a0 30O, A.J F- 5' 1 1 S- Ste-• to 0 1 0( C, a Leh 7— So k -M � a y Wetland Mitigation Bank Project October 20, 1993 Public Meeting Questions posed by attendees to City and consultant staff: 1. Can public programs use the bank? 2. What are advantages to developer? 3. Is City going to fill the major wetlands just south of SW 27th Street? 4. Does Boeing own all of Longacres? What is the zoning surrounding sites and in area? 5. Does City own strip above bank site #1 (P-1 Channel)? 6. Have you measured elevation of water level in wetland south of 27th and east of Longacres and compared with groundwater on bank site #1? 7. Saw program on public TV. Wetland biologist says wetland creation not possible. How do you respond to that? 8. What is longest time period until created wetland established? What is its success? 9. What do you do with canary grass? 10. When do you call a mitigation a success so credit can be withdrawn? 11. How is bond handled? 12. What department in City is in charge of project? Who is responsible? One or more City Departments? 13. Has ESGRWP been resurrected? Will they coordinate with Kent? 14. Objective refers to maintain 100-year flood storage function of wetland. Is this FEMA or R. W. Beck study? 15. What is section on objectives addressing 1:1 ratio? 16. What about displacement of wildlife during establishment of wetlands? 40 - 50 years? 17. How are buffers addressed/incorporated? 18. Has Springbrook been altered? 19. Can Springbrook be incorporated/restored? 20. Will membrane cause stagnation? Will membrane use be limited? 21. Are you on schedule for implementing P-1/Springbrook? 22. What about drainage of Panther Creek? Wetland Mitigation Bank Project Questions from Public Meeting of 10/20/93 Page 2 23. What kind of wetlands do you plan to create? 24. Suggest funding come in possibly 50% developer, 40% City, and 10% County. 25. Will you consider public participation in monitoring? Questions posed by City and consultant staff to meeting attendees with responses: 1. Any comments or questions on the conceptual renderings and on-site considerations? a) Should there be public access to the site? How much? Limited access. Confined to specific areas. Concerned that developer may try to utilize sites as amenity. Domestic animals should be restricted. Restrict to joggers. Should be meandering. b) What type of interpretive material would be useful? Include signs for: plant species; explanation of why wetland created; historical background; Indian heritage; signs should be restricted to one area. e) Are there any other features that should be included, such as trails, flood storage, and wildlife habitat? Raptor habitat. Possibly go for higher quality habitat on Site 1. 2. Should public and private users be equally eligible? Both should be allowed. May depend upon timing. 3. Should the City limit the size of wetlands that are eligible? Possibly exclude Category 1 wetlands. Want to see mitigation established before impact. Better to have smaller pilot projects (sending property impacts less than one acre). H:DOCS:93-1034:SSW:ps Wetland Mitigation Bank Project Attendees of 10/20/93 Public Meeting: Colleen Cole-Bowron Martha Parker Laurinda Johnsen 601 Cedar Avenue South 18028 - 187th Ave SE P. O. Box 161 Renton WA 98055 Renton WA 98058 Renton WA 98057 432-5498 Ray E. Fournier Kent Lind T. Steger 4700 Talbot Road South 6027 -28th Avenue NE 6209-30th Avenue NE Renton WA 98055 Seattle WA 98115 Seattle WA 98115 526-0789 528-6019 Sally L. Steiner Richard Chase 17818 - 109th Avenue SE City of Kent Renton WA 98055 220-4th Avenue South 228-0124 Kent WA 98032-5895 859-3950 H:DOCS:93-1033a:SS W:ps City of Renton Wetland Mitigation Bank Project Property Owner/ Development Community Meeting ATTENDANCE SHEET Name Addr ss Zip Phone C,-r,l a f GN 8LJ6. 2-4 m,(,L a ,v.. 5 2-71-5511 o � - - .s � it277-z47s _Ti►n PU LA le 7CO S f4 6vs �g lc zZ3-625Z ?a f6S—i17v us4 9(6l Z :I- tj L LS I( -Lg6-A,K 5 a (�e_,V-e, tAA- Eoo$ (41. Alto '�ra[TMC�Q. 2, 580� Lai vb� �vkt�,r�l �Bz2 . Wetland Mitigation Bank Project October 21, 1993 Development Community Meeting Questions/Comments: 1. Developers want to know all the costs and have assurances of closure of responsibility in a reasonable amount of time. a. Ideal scenerio. Construct the site and identify all costs (no hidden costs) so that developer who meets eligibility pays cash and is done. b. Without actual costs set an upper limit on potential costs so that maximum potential liability is known. C. Limit the use of hold harmless and transfer of liability requirements so that the developer can see closure to his responsibility. d. Minimize the amount of time that a developer must be responsible. 2. Development community desires "user friendly" regulations that are not overly restrictive. a. Consider ordinance revisions. 1. Eliminate avoidance/minimize requirement for Category 3 wetlands. 2. Develop single payment scheme. 3. Consider fee-in-lieu program. 4. Allow impact before mitigation. - b. Reduce site plan approval time. C. Simple eligibility requirements with minimum of paper work and cost to determine eligibility. Developer typically not willing to sink money into a site unless a specific project is on line. Must be setup to realize some return for the expenditure in order to justify the costs. 3. Suggestions for funding program and increasing developer awareness and confidence in using bank sites for mitigation. a. Fund full bank site development using special assessment district or some sort of general tax and establish successful mitigation prior to issuing credit. Wetland Mitigation Bank Project Questions from Public Meeting of 10/20/93 Page 2 b. Construct entire bank site 2 to mitigate for the 5.33 acre obligation and use excess acreage as pilot mitigation bank and demonstration to development community. C. Amenities, such as trails, should come from City, not developer, funds. Developer should be responsible for basic mitigation for the associated impact. d. The City should consider cost sharing with the developer for the mitigation partly because of the increase in tax base that may result 4. Other comments/questions. a. Will the program allow other types of credit, such as compensatory storage for filling the floodplain? b. When will a potential user be considered eligible? Following SEPA review, permit:issuance, or at some other time? C. Will the program be first come, first serve, and how long will a user remain eligible once accepted? d. Public and private users should both be allowed. e. The program should not exclude greater than one acre impacts if all requirements are met , f. The program should not be limited to only Catagory 3 impacts. g. Corps has rarely issued permits. However, projects that have gone through the Corps process should be allowed to use the bank. h. General interest and support for the banking concept, but need to see more information. Questions for Discussion 6--ra364L 'it, /sS3 1. Are there any comments or questions on the goals and objectives? 2. Do you have any ideas on how we can reduce the cost for use of the sites for mitigation? a. Volunteer plantings? Donated interpretive materials? Volunteer maintenance and monitoring? b. Cost sharing? 1) Percentage split of all costs by public and private? 2) City accept responsibity for all maintenance bonding and contingency costs, or for all of these costs in excess of a certain dollar value? c. Limit the impacts to Catagory 3 isolated wetlands less than one-acre so that permitting is simplied and implementation costs are less expensive? d. Simple eligibility requirements and reduced permit costs for eligible properties? 3. How should users be chosen? a. First-come-first serve, regardless of wetland size, function, and value? b. At what point should a user be considered eligible? 4. Should public and private users be equally eligible? 5. Should the City limits the size of wetlands that are eligible? 6. Is anyone interested? How can the program address your needs in order for you to consider the City mitigation sites as a viable option? 7. Site design questions. a. Should there be public access to the site? Trails? No trails? Perimeter trails? Extensive trails? b. What type of interpretive material would be useful? Displays illustrating the vegetative, wildlife, hydrologic and hydraulic, and geologic features to be observed? Descriptions of wetland value and function? Project objective? Historical background of Green River Valley and project sites? c. What other features should be included? Flood storage? For Springbrook Creek? For private and public development projects? Type of wildlife you would like to see use the site? Wildlife habitat features? Nest boxes? Snags? Wetland Mitigation Bank Project Attendees of 10/21/93 Public Meeting: Tim Puryear Jim Douma H. Seelig 700 5th Avenue - STE 7600 521 Wall Street P O Box 1925 Seattle, WA 98104 Seattle WA 98121 Bellevue WA 98009 223-6292 448-4699 454-0885 Janet Garrow Rhys Sterling Paul B. Crane 701 -5th Avenue - STE 7000 800 Bellevue Way NE-#376 The Boeing Company Seattle WA 98104 Bellevue WA 98004 P O Box 3707 -MS 63-41 587-0700 454-8272 Seattle WA 98124 965-1170 H:DOCS:93-1035a:SSw:ps APPENDIX E LIST OF LOCAL, STATE, AND FEDERAL AGENCY REPRESENTATIVES INVITED TO AGENCY MEETINGS Regulatory Agencies Gail Terzi Eric Stockdale T. J. Stetts Wash. Dept. of Ecology U. S. Army Corps of Engineers 3190 - 160th Avenue SE P. O. Box 3755 Bellevue, WA 98008 Seattle, WA 98124-2255 Bill Riley Andy McMillan JoAnne Stellini Fred Weinman Wash State Dept. of Ecology Allisa Ralph Environmental Protection Agency P. O. Box 47600 U.S. Fish and Wildlife Service 1200 Sixth Avenue -WD-128 Olympia, WA 98504 3704 Griffin Lane SE-STE 102 Seattle, WA 98101 Olympia, WA 9801-2192 Chuck Natsuhara Joe Robel Rick Albright Soil Conservation Service Wash State Dept of Fisheries Dept of Environmental Protection Evergreen Plaza Bldg -Room 502 115 General Adm. Bldg. AX-11 1200 Sixth Avenue 711 Capital Way P O Box 43155 Seattle, WA 98101 Olympia, WA 98501 Olympia, WA 98504-3155 Patricia Thompson Ginny Broadhurst Rod Den-Herder Wash State Dept of Wildlife Puget Sound Water Quality Authority Soil Conservation Service 16018 Mill Creek Blvd. P. O. Box 40900 -M/S PV-15 935 Powell Avenue SW Mill Creek, WA 98012 Olympia, WA 98504 Renton WA 98055 Tom Mueller Becky Herbig Mary Burg Army Corps of Engineers Wash State Dept of Wildlife Wash State Dept of Ecology 4735 E. Marginal Way South 16018 Mill Creek Blvd 3190- 160th Avenue SE Seattle WA 98124-2255 Mill Creek WA 98012 Bellevue WA 98008-5452 Anne Watanabe Norm Stewart Theodore Muller Wash State Dept of Ecology Wash State Dept of Ecology Wash State Dept of Wildlife 3190 - 160th Ave SE WQFAP-MS PV-11 16018 Mill Creek Blvd Bellevue WA 98008-5452 Olympia WA 98504 Mill Creek WA 98012 H:DOCS:Agency 1:SSW:ps Interested Agencies James Schafer Bob Lyon Wash State Dept of Transportation Soos Creek Water/Sewer P O Box 47329 P O Box 58039 Olympia WA 98504-7329 Renton WA 98058-1039 Jonathan Fordge Heather Stout R. O. Aye Metro King County Surface Water Mgmt Wash State Dept of Transportation 821 Second Avenue MS 81 111 Third Avenue STE 1100 P O Box 330310 Seattle WA 98104 Seattle WA 98101 Seattle WA 98133-9710 Bill Wolinski Dennis Dowdy Ross Ernst City of Kent Public Works Tim Carlaw Phil Fraser 220 Fourth Avenue South City of Auburn Public Works City of Tukwila Public Works Kent WA 98032-5895 25 West Main 6200 Southcenter Bldg Auburn WA 98001-4998 Tukwila WA 98188 John E. Nelson King County Drainage District#1 601 West Gowe Kent WA 98032 H:D OC S:Agency2:SS W:ps Draft City of Renton Wetland Mitgation Banking Program TY . . Regulatory Requi=ents 1993 CHAPTER 1. INTRODUCTION The City of Renton is developing a wetland mitigation banking program and plan that is consistent with the City's Wetland Management Ordinance (Ordinance Number 4346) (City of Renton 1992) and Comprehensive Plan(City of Renton 1993a). The mitigation banking program is a means to comply with the policy of no net loss of wetland resources in a manner that optimizes the ecological benefits while improving the cost-effectiveness of compensatory mitigation. The wetland mitigation banking program will use larger off-site areas to mitigate for a number of independent wetland development conversions. The basic concept involves a developer purchasing "wetland mitigation banking credits" from the City which has "banked" them for this purpose. The concept of developing a mitigation banking program resulted from three primary actions: (1) the City undertaking an inventory of its wetlands, (2) the City developing and adopting a critical areas ordinance for wetlands (City of Renton 1992) pursuant to the Growth Management Act and, (3) discussions between the City and Glacier Park, a private landholder in the Valley, on the concept of mitigation banking. During the wetlands inventory, the City found that a number of high-value wetlands were still located within the Black River Drainage Basin [i.e., the Green River Valley (herein referred to as the Valley)]. There were also numerous lower quality wetlands that potentially reduced property owners' property values. Figure 1 shows the extent of inventoried wetlands and streams within the Black River Drainage Basin. The presence of both high and lower quality wetlands is the direct result of historic activities in the Valley. Originally, the Green River Valley was a flood plain with relatively high-value wett dds. Figure 2 shows the extent of natural wetlands prior to development in the Valle in 1972? During the P P Y g 1960s and 1970s, draining and filling activities for industrial, commercial, and some residential development resulted in cumulative losses of wetlands within the Valley. Figure 3 shows the yextent of filling from 1975 to 1987. Although many of the filled areas were developed, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These tJ' depressional areas developed a perched water level (water that sits on an elevated area) and eventually developed into small lower quality wetlands. Many of these undeveloped parcels were owned by Glacier Park Company, a subsidiary of Burlington Northern Railroad. f.�(y _iHl' 6 Although the City was drafting an ordinance for the protection and management of wetland resources in 1992, it was also concerned with retaining an economic base and industrial lands. Concurrently, Burlington Northern (BN) decided to divest some properties held by the Glacier Park Company, a subsidiary to BN. BN also wanted to improve the market value of some of its other Valley properties. In 1992 the Renton City Council passed a Wetlands Ordinance (City of Renton 1992) which provided opportunities to establish a wetland mitigation bank. Properties within the Valley that met certain criteria could establish and/or use an existing mitigation banking program, as long as the result was no net loss of wetlands. After meeting with the City Parametrd, Inc. 1 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin 7 to discuss mitigation banking' Gla ier Park donated to the City two large parcels that contained larger ' ly highe Category 3 wetlands In exchange, the City allowed Glacier Park to make some smaller parcels containing lower quality Category wetlands (less than 1 acre in size) more saleable by filling up to .99 acres of wetland on six different parcels, representing a total of 5.33 acres of fill.' f � ..�L�R. ,•N-. �ss� 1 ��- C�, 1 �y � �a�•-�-ey-� .G�Gr ��fir ,�'�'. �..,u�-' /� The City acquired two sites totaling 44.80 acres withirr-dhe city limits. These sites are to be used for compensatory wetland mitigation for theC`5 33 acres of fill allowed on other small parcels still under Glacier Park ownership, and for mitigation banking by other developments other than Glacier Parks in the Valley to offset losses to lower quality wetlands. These two parcels called Mitigation Banking Site 1 and Mitigation Banking Site 2 are shown in Figure 4. Miti ation Banking Site 1 is located north_ Southwest 33r� Street south of the P-1 5-rK--( el easement_ed bythCi of Rento east of the Burlington Northern Rail Road, - 'C' far west of Oaksdale Avenue Southwest (Sec 25, T 23N, R 4E) (see Figure 4). The site is 30.97 acres and is zoned industrial. It is bordered by developed land zoned for commercial and F*"- U industrial development along the eastern half of the southern boundary. Undeveloped commercial 1� pig and industrially zoned land is adjacent to the western half of the southern boundary and to the ®p t,t` eastern and western boundaries (David Evans and Associates 1991 a). The site consists primarily IA� V of revegetated fill material, placed approximately 20 years ago, along with 12.19 acres of 1p,fl relatively undisturbed upland meadow and shrubland and 18.78 acres of young forested and shrub wetlands. 5� Mitigation Banking Site 2 is located south of Southwest 34th Street, west of Springbrook Creek, north of Southwest 39th Street, and east of Oaksdale Avenue Southwest (Sec 31, T 23N, R 5E) (see Figure 4). The site is approximately 13.93 acres and consists of 7.16 acres of upland meadow and 6.77 acres of emergent, young shrub and forested wetland (David Evans and Associates 1991 b). The site was filled over the past 20 years; the topography is relatively flat with small depressional areas. It is bordered to the north by undeveloped industrial and commercially zoned land. Once the City acquired the two mitigation banking sites, it assembled an interdepartmental team consisting of representatives from Surface Water Utility, City Planning, and Parks and Recreation to manage and develop a mitigation banking plan (City of Renton 1993b). Once the plan is finalized and approved by the City, the City will implement the plan and mitigation program. The City intends to operate, maintain, and monitor the mitigation banking sites. ' Filling of these wetlands was permitted by the U.S. Army Corps of Engineers under the Nationwide 26 permit process. Parametrix, Inc. 5 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin i Tq� TALBOT RD S Q 61� v7 eOT9 G s � D 07 j�2 SHATTUCK 3 aos a /Q P ANTHER CREEK WETLAND d � SHOPPING CENTER J / (n ~ / C c~p N N _ > m V cc / c V (n 3 LIND AV S LIND AV SW Q = Ln U7 0) LL — --- — / O zw E O If �y /EK C7 1 > : <:<::i;:>;::>:??1 OAKESDALEAVSW j Jp� /�GR z i:::: �POO N��l z \ % \ PP�NP G LPN m \ Y z ;0 to ONf ; / Q LONGACRES a \ % m l RACE TRACK c7 r ......;:.::::<;;:::>:;.;::;:.;;<� % z 01. 1ii` +JACKSON SW REN TON CITY LIMITS MILL CREEK ////�riiiriiiiirriiiiiriiiiiiiiiiiririiii✓iriiiiiiifriirriiiririiiiiriii11;i iiiiriiiiiiiririir✓iiiiiiirriiiiiiiiiriiiii�iriiiiiiiiiiiiiiiiiriiiiiiiiiiiiiiir \ BLACK RIVER f � � - PUMP STATION TUKWILA FOREBAY \ ; � Figure 4. Mitigation Banking G'qq Sites 1 and 2 F 4- BLACK q�L cc RIVER q e Source: R.W. Beck and Associates 1991 PUMP STATION TO GR N- UWAM / EE D ISI�' SCA LE IN FEET EE RIVER N 1 500 1,000 • Provide incentives for overall net gain of wetland functions and values for new development (EN-6.7, Comprehensive Plan). • Establish and protect buffers along wetlands to facilitate infiltration and maintain stable water temperatures, provide for the biological regime, reduce the volume and velocity of runoff, and provide for wildlife habitat (EN-6.2, Comprehensive Plan). • Encourage preservation and enlargement of existing habitat areas through development incentives (EN-14.3, Comprehensive Plan). • Increase the community's understanding of the City's ecosystem and the relationship of the ecosystem to water resources (EN-11.2, Comprehensive Plan). • Encourage public access to wetlands for use when sensitive habitats are protected(EN-6.8, Comprehensive Plan). • Where appropriate, combine all critical areas and environmentally sensitive areas with recreational facilities to provide public access and trail linkages through separators (EN- 15.7, Comprehensive Plan). V Parametrix, Inc. 9 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.p1n 4.2 ELIGIBILITY CRITERIA 2: Is the Proposed Project Located Within the Black River Drainage Basin? Standard C4l Jb V-J' 9o'h` The altered wetland must be located within the Black River Drainage Basin, including the Green River Valley. 4.3 ELIGIBILITY CRITERIA 3: What is the Size and Category of the Wetland That May be Affected? Standard? Wetlands classified as Category 1, 2, or 3 by the City that may be altered consistent with the Wetland Management Ordinance (Ordinance Number 4346) are potentially eligible to use the mitigation banking sites. Written documentation from the Corps on the jurisdictional status(e.g., isolated, above the headwaters, less than 1 acre) of the wetland to be altered would be required. For sites with wetlands that are less than 1 acre and above the headwaters but do not have specific project plans, a copy of the jurisdictional letter from the Corps would need to be submitted to the City. For sites with wetlands that total less than 1 acre, are above the headwaters, and have specific project plans, a copy of the Nationwide Permit would need to be submitted to the City. Impacts to wetlands that require an individual permit (Section 404) from the Corps and/or Ecology (e.g.,Nationwide 26 for impacts to wetlands between 1 and 2 acres that are above the headwaters) may also be compensated for at the mitigation banking sites. A developer would need to provide the City with a copy of the appropriate permit along with written documentation that the state and federal agencies concur on using the mitigation banking sites for compensatory mitigation. 4.4 ELIGIBILITY CRITERIA 4: Is On-site Mitigation Feasible? Standard The wetland to be altered would be considered eligible for use of the mitigation banking program when: • The hydrology and ecosystem of the original wetland and those adjacent lands and/or wetlands which benefit from the hydrology and ecosystem will not be substantially damaged by the on-site loss; and This standard may need to be revised based on decisions regarding some of the policy issues in Chapter 3. Parametriz, Inc. 30 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Eligibility Criteria 1: MITIGATION BANKING No DOES THE PROJECT COMPLY WITH THE SOULD NOT BE CITY WETLAND MANAGEMENT ORDINANCE CONSIDERED (ORDINANCE NUMBER 4346)? Yes No Eligibility Criteria 2: IS THE PROPOSED PROJECT LOCATED WITHIN THE BLACK RIVER DRAINAGE BASIN ? d(, Yes Eligibility Criteria 3: 012 #t/1 No IS THE IMPACTED WETLAND 4<1 LESS THAN ONE ACRE,AND ISOLATED OR ABOVE THE HEADWATERS? Yes Yes Eligibility Criteria 3: IS ON-SITE MITIGATION FEASIBLE? No ELIGIBLE FOR MITIGATION BANKING PROGRAM Figure 5. Flow Chart to Determine Eligibility for Use of Mitigation Banking Program CHAPTER 5. REGULATORY REQUIREMENTS TO IMPLEMENT THE MITIGATION BANKING PROGRAM Any work necessary to restore the uplands on the mitigation banking sites—involving any in- water work, alteration of existing wetlands, grading and filling—is potentially subject to regulations implemented by federal and state regulatory agencies and the City of Renton. The types of federal permits associated with altering the on-site wetlands that may be needed will be dependent on two primary factors: 1. Whether the City chooses to excavate any of the existing on-site wetlands (e.g., reed canarygrass wetland vegetation adjacent to Springbrook Creek) as part of the effort to restore the functions and ecological communities to the site. 2. The jurisdictional determination on the wetlands within the mitigation banking sites being completed by the Corps. Currently, the site plans being developed for the mitigation banking sites do not include altering the existing wetlands. There are two reasons for maintaining the existing on-site wetlands: (1) the City of Renton's Wetland Ordinance does not currently recognize enhancement of wetlands as a form of compensatory mitigation, and (2) a Corps permit (e.g., Nationwide 26 or 27, or an individual permit) would be necessary to undertake excavation activities within the wetlands. If the Corps determines that the wetlands within the mitigation banking sites are "adjacent," and the City chooses at some future date to excavate lower quality portions of the existing wetlands, a Section 404 Individual Permit would be required. Alternatively, if the Corps determines that one or both mitigation banking sites are above the headwaters, and the City chooses at some future date to excavate lower quality portions of the existing wetlands on the mitigation banking site(s) (i.e., less than 1 acre, or between 1 and 2 acres), Nationwide Permits 26 and/or 27 would be required. In addition to the permits associated with restoring wetland communities on the mitigation banking sites, the City would also need to initiate discussions with the King County Drainage District to determine whether reestablishing a hydrological connection with Mitigati n B Site 2 requires any type of permit. �,,,y,,, ,,< ,,o avi it o, v k L y The federal, state, and local permits that may be needed by the City of Renton to undertake construction activities to restore the upland sections of the mitigation banking sites to wetlands are identified in Table 3. Parametrix, Inc. 32 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" State of Washington State Environmental All state and local Probable SEPA lead Specific to each SEPA review must As with NEPA, Policy Act(SEPA) permits or approvals agency: City of Renton City/County. precede the issuance of supplemental issued for construction any state or local environmental review or operation of the permits or approvals by is required only if facility must comply 7 days. An EIS and there are(I) with the procedural associated studies "substantial changes to requirements of SEPA. generally take at least a proposal so that the A DNS, MNDS, notice 10 months to 1 year to proposal is likely to of adoption, or final complete, assuming no have significant EIS must be issued appeals. If SEPA adverse environmental before agencies issue review is "adopted,"the impacts"or(II)"new permits or approvals. process can be information indicating completed in about 1 a proposal's probable month after the significant adverse completion of the environmental impacts. SEPA process. Hydraulic Project An HPA may be Washington Ch. 75.20 RCW; HPA application must Permits must Approval(HPA) required if project Department of Fisheries Ch. 220-110 be processed within 45 demonstrate crosses/affects fresh WAC calendar days of the "substantial progress water streams. submission of a on construction on that complete application portion of the project and after issuance of a relating to hydraulic final EIS. No public approval within 2 hearing required. years of the date of issuance." HPA approvals may be granted for a period of up to 5 years. Temporary Required for Washington Dept.of Ch. 90.48 RCW; Generally,temporary None established by Modification of Water construction activities Ecology(Ecology), WAC 173-201 water quality regulation;permit Quality Criteria that temporarily violate Northwest Regional and 173-222. modification must be terms and conditions water quality criteria. Office. sought 30 days prior to generally cover May be required for any in-water work. duration of work stream diversion requiring the structures. modification. Water Quality Required of any Ecology Headquarters; Federal Clean Timing of certification Not Applicable Certification(§401) applicant for a federal Central Programs; Water Act, varies. license or permit to nv'ggnmental Review Section 401;Ch. conduct any activity Secti6n,Olympia. 173-225 WAC that may result in any discharge to surface waters. CZMP Consistency Required for permits Ecology, Shorelines 16 USC§1451 et Certification can Not applicable. Certification and licenses affecting Program, Olympia. seq.; 15 CFR generally be obtained in shoreline areas and is parts 923-930 60 days. usually considered during the Section 404 or Nationwide permit process. National Pollution Storm water pollution Ecology, Industrial Federal Clean Generally, 30 days Generally, covers Discharge Elimination control for construction Storm Water Unit. Water Act S 402; following receipt by duration of work. System(NPDES) activity that disturbs 5 40 CFR parts Ecology of Notice of Permit or more acres. 122-124 RCW Intent 90.48, 90-52; WAC 173-220 Parametrix, Inc. 34 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Baseline information on features of the Black River Drainage Basin that is pertinent to the mitigation banking sites is followed by a summary of existing information for the two sites, and a discussion of opportunities and constraints associated with restoring the uplands portions of the mitigation banking sites to wetlands. 6.2.1 Hydrology of the Black River Drainage Basin i Springbrook Creek and Panther Creek are the two primary streams within the basin (Figure 7) (R.W. Beck and Associates 1993). Springbrook Creek flows north along the valley. The upper basin includes a large portion of the City of Kent, including 4 11 Creek. Major tributaries to Springbrook Creek outside of the basin include Mill Creek 4d Garrison Creek. The lower portion of Springbrook Creek, known as the P-1 channel, has been enlarged over the years to accommodate flood flows (R.W. Beck and Associates 1993). Flow in Springbrook Creek can Vange from an av a e minimum (low) flow of approximately 8 cfs to a peak flow of C�roxim 900 cfs during severe flood events. Springbrook Creek joins the Black River at �Y the Black Rives mp Station and is considered to be a small remnant of the old Black River that drained Lake Washington before the Lake Washington Ship Canal and Ballard Locks were constructed by the Corps in the 1920s. The pump station transfers water from the Black River to the Green River. Upstream from Southwest Grady ja , Springbrook Creek has been deepened and widened in past years by farmers 6�9 ons, d the King County Drainage District No. 1. AU ZF- V�' ^ Panther Creek is another drainage that affects the valley system (see Figure 7). The Panther Creek Wetland has two primary runoff sources, Panther Creek and the Rolling Hills Basin. Panther Creek drains the upland plateau in the eastern portion of the basin. Panther Lake is located at the headwaters of Panther Creek (see Figure 1). Panther Creek enters a large wetland, the Panther Creek Wetland, which extends along the east side of the State Route 167 (SR-167). During large storm events;excess flow from Paanth Cjek�ters the south end of the wetland. erges wi a stem water 4 Street, which eventually discharges into S ringbrook Creek. Excess runoff from the o Bing Hills Basin also enters at a no emend of the we an uring large storm events. Flows from the Rolling Hills Basin are connected to the Renton Village Shopping Center conveyance system (R.W. Beck and Associates 1991) (see Figure 7). The shopping center carries runoff to a culvert crossing underneath Interstate 405 (I- p, 61A)i-'�I 4 405). From the I-405 crossing, a low flow channel carries runoff along the east side of SR-167 to a culvert that crosses west underneath SR-167; this culvert carries flow west and discharges �,,&-into Springbrook Creek. / J ''II �O 6.2.2 Land Use and Capacity Present and future land uses in the Panther Creek and Springbrook Creek drainage basins have been described by R.W. Beck and Associates (1993) and were based on aerial photographs of the area from 1988 and 1989, area comprehensive management plans, and local zoning maps. Anticipated changes in the area of land zoned for a variety of uses is shown in Table 3. Parametrix, Inc. 39 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin U Ta Anticipated changes in land use in acres (R.W Beck and Associates 1993). 1 � Land Use Springbrook Creek Panther Creek V Commercial +712.9 +8.2 Multi-family residential -14.0 +96.0 \, High-density residential +229.4 +347.7 x� Medium-density residential +144.4 -62.4 Low-density residential -216.3 -91.20 Upland forest -56.3 -160.1 Upland cleared -183.1 -123.3 Lowland undeveloped -626.9 -12.3 Lake 0 -8.1 ". + indicates increase in land use for the particular zoning - indicates decrease in land use for the particular zoning Table 3 indicates that the anticipated changes in land use in the Springbrook Creek Drainage Basin will be toward more commercial and high- and medium-density residential housing. Commercial development currently predominates in the lowland areas in the western portion of the basin (i.e., Springbrook Creek Drainage Basin) and in the Renton commercial district. A large portion (approximately 1,510 acres) of the Springbrook Creek Drainage Basin is currently undeveloped; however, most of this area is expected to be converted to commercial and high- density residential development. Future development in the Springbrook Creek Drainage Basin will convert the existing undeveloped forest land and low-density residential areas to predominately commercial and high-density residential. The City of Renton estimates that commercial portions of the Springbrook Creek Drainage Basin will be completely developed within the next 5 to 7 years. Assuming that development occurs uniformly during this period, approximately 250 acres of land will be developed each year in the Springbrook Creek Drainage Basin (R.W. Beck and Associates 1993). Full build-out of the Panther Creek Drainage Basin is expected to occur at a lower rate estimated to be between 15 and 20 years. Thus, the amount of land developed each year in the Panther Creek Drainage Basin would be approximately 45 acres. 6.2.3 Water Quality Sediment Erosion Sediment Erosion Sediment loading in the Black River Drainage Basin can deteriorate the water quality and affect aquatic organisms residing in the major streams and tributaries. The major sources of sediment loading in the basin are upland erosion in the watershed and in-stream channel erosion. Upland Parametrix, Inc. 41 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin During the 1960s the Soil Conservation Service (SCS) undertook a planning exercise to look for solutions to interior valley flooding problems. In addition, construction of the Howard Hanson Dam in 1962 helped prevent major valley flooding (provides an estimated 500 to 600 years of protection) from the Green River; however, it did not solve the interior valley flooding problems when Green River flows closed the flood gate for the Black River. In 1965, the SCS developed 3 the East Side Green River Watershed Work Plan which recommended land treatment measures (e.g.,cropland management,wildlife preservation/enhancement)and structural measures(e.g.,new or improved drainage channels for collection and conveyance of runoff, discharge structures, such as pump stations, and improved outlet channels) to manage storm water runoff and to resolve the interior valley flooding (R.W. Beck and Associates 1991). The Black River Pump Station (BRPS) was completed in 1972. Its function is to lift the interior valley drainage so that it flows by gravity into the Green River. During the late 1970s and 1980s �,r71 additional studies were completed on alternative flood storage and control measures;these studies �l led to the development of alternative channel alignments (i.e., enlarged and realigned 11.1 miles of stream channel to provide storage and convey flood waters to the BRPS), the creation of two flood storage ponds (i.e., construction of the BRPS forebay to provide flood storage when the BRPS has to restrict pumping rates during high Green River flows) and a reduction in channel e �1� size (i.e., reduction of the P-1 channel width within the City of Renton from 165 to 200 ft to 70 to 80 ft). A 5W q Between 1984 and 1990 the City of Renton d the SCS undertook the construction of the BRPS forebay, the P-1 channel from the forebay t SW Grady Way, the Grady Way Box Culvert, the P-1 Channel East Side Retaining Wall, the -405 Box Culvert (not operational since no channel improvements have been made to allow S ringbrook Creek to flow through the structure), and the SW 16th Bridge replacement. In ad tion, the City undertook an evaluation for allowing construction of the P-l/P-9 Channels sou to SW 43rd Street. This process resulted in the City determining that the final SCS Environmental Impact Statement (EIS) could not be adopted without a new EIS or supplemental EIS. Subsequently, the City retained R.W. Beck and Associates and associated consultants to gather and evaluate the technical and environmental information needed to support a supplemental EIS using two independent but coordinated planning efforts: the East Side Green River Watershed Plan (R.W. Beck and Associates 1991) and the Black River Drainage Basin Water Quality Management Plan(R.W. Beck and Associates 1993). Potential flood control alternatives presented in these plans include: • A no-action alternative (i.e., no flood control alternatives are implemented) • Localized improvements to Springbrook Creek combined with other Valley area drainage improvements to eliminate existing flooding problems in the Valley area • Establishing a flow diversion channel (SCS P-1 and P-9 Channel projects with modifications) and maintaining Springbrook Creek as a fisheries flow channel Parametric, Inc. 43 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 7-4 ;_5 *1 • Pumping storm water-froiri-fli -Cent lagoon into th�reenr No formal decisions have been made about the flood control alternatives presented in the most recent plans prepared by R.W. Beck and Associates (1991;1993). 6.2.5 Results of Review of Baseline Information and Field Assessment The results of the field assessment of the two mitigation banking sites indicate that both sites contain relatively low-value seasonally perched wetlands that are generally composed of cottonwood,Populus balsamifera;red alder,Alnus rubra; salmonberry,Rubus spectabilis; willow, Salix spp.; and reed canarygrass, Phalaris arundinaceae. The wildlife habitat value of the mitigation banking sites is limited by development adjacent to and near the properties; although the wildlife habitat value of the large wetland and its associated buffers on Mitigation Banking Site 1 appears to be greater than Mitigation Banking Site 2. Both sites support deciduous trees that are well developed but not fully mature. Consequently, opportunities for cavity-feeding and nesting birds, for example, are limited. The relatively young age of the forested portions of both sites and the relatively low species diversity within the plant communities limit the value of these sites for wildlife. In addition, there are few, if any, permanently wet areas on either site. The existing wetlands are seasonal in character and possess relatively low functional values for flood water abatement and storage, and water purification. The wetlands are also poorly developed and somewhat artificial (i.e., developed on pans in isolated depressions on top of fill), and occur at elevations 5 to 9 feet higher than neighboring water bodies (e.g., Springbrook Creek) Both sites have large areas in which reed canarygrass and introduced blackberry species (Rubus discolor procera, R. lacianatus) have become established. Mitigation Banking Site 1 also has areas in which Scot's broom (Cytisus scoparius) grows. These plant species will continue to expand their ranges unless shaded by taller vegetation, removed, or otherwise controlled manually -4x-chemically. Mitigation Banking Site 2 does not show evidence of human intrusion, but Mitigation Banking Site 1 is frequently used as a sport off-road vehicle area, an activity that has resulted in significant disturbance to the landscape despite efforts by the City to restrict entry for this purpose. A significant amount of fill has been placed on both sites, and the depth of fill appears to be as great as 10 ft in some places. This material generally has low organic content and relatively permeable sandy soil and, although soils in the wetland areas show signs of mottles, the soils may not have been hydric when deposited. Using a backhoe, three soil test locations were dug on Mitigation Banking Site 1 and five were dug on Mitigation Banking Site 2. The soil test locations are shown in Figures 8 and 9, and the results are presented in Figures 10 and 11. Photographs of the soil test locations are provided in Appendix B. Parametrix, Inc. 44 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 18 : : . . W - 13C : : : : • : : • 14 W - 12 ' .. : . . HIGH FLOW DIVERSION ` CHANNEL IMPROVEMENT ��✓� 16 . . : Upland endow an shr land co munity WETLAND M: : .,•... : , I 1 .1--8- Young, forested, shrub. and I emergent wetland communtity . . • . g , . WETLAND M18, :•`• . . .. . .. • . I . . . W - 22 i : W - 2 WETLAND L. WETLAND J: Shrub community Shrub community _ Upland meadow and shrubland community Sam : W _ 14 SW 33rd Parametrix, Inc. DRAFT W-22 onesn and Stokes, 1991 FIGURE 8 0 75 150 - — = = Mitigation site boundary EXISTING CONDITIONS SCALE IN FEET October 19, 1993 SOURCE: MITIGATION SITE 1 CITY OF RENTON, 1993 = Soil Test Pit Location (approximate) Y SURFACE SURFACE SURFACE SURFACE SURFACE 1 ELEVATION 2 ELEVATION 3 ELEVATION 4 ELEVATION 5 ELEVATION SURFACE 19.5 16.5 :. 16 15.5 16 2 17.5 14.5 14 13.5 14 \\1\ 4 15.5 12.5 12 11.5 12 w 13.5 F- 6 10.5 5 10 9. 10 w w _z a w 11. 8 5 5 8 8 7.5 0 8 ............... ................ ! ♦ / r r / \ \ \ \ \ \ '' JiSi rl:i::?: 10 9.5 6.5 6 5.5 6 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ -12 7.5 4.5 4 " " " 3.5 ` \ \ " " 4 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ -14 5.5 2.5 2 1.5 2 Sandy Silty Fill Seepage Silty Sand Fill with Mottles Concrete Figure 11. Fine Sand Clay ``` ```` Black Sand Soil Test Location Characteristics ® Iron Oxide Layer Sandy Silt/Silty Clay Historic A Horizon of Mitigation Banking Site 2 6.3 SUMMARY OF MITIGATION BANKING SITE INFORMATION 6.3.1 Mitigation Banking Site 1 :TT IS ? Mitigation Banking Site 1 is 30.97 acres and is within the 100- ear Green River floodplain. Approximately one-third of the site has been cleared, or cleared and filled, over the past several years. In 1970 the site was cleared of all trees, and a tributary to Springbrook Creek that meandered through the site was filled in, creating localized wetlands (Hart Crowser 1991 a). Farming was the predominant activity on the site until the early 1980s. Three wetland communities were identified and delineated by David Evans and Associates (1991). The wetland communities typically occur in the relatively undisturbed areas and the majority of upland communities occur in elevated areas that have been more recently filled. The on-site wetlands are considered to be Category 3 wetlands, according to the City of Renton's Wetland Management Ordinance. 6.3.1.1 Vegetation Communities Several vegetation communities occur on the site; these include upland meadow and shrub communities, wet meadow, and scrub-shrub and forested wetland (David Evans and Associates 1991) (see Figure 8). The upland meadow communities are variable in the species composition, but in general are dominated by upland and facultative upland species. Species common to the upland meadow community include: creeping bentgrass,Agrostis stoloneifera; English plantain, Plantago lanceolata; velvet grass, Holcus lanatus; common tansy, Tanacetum vulgare; hairy cats-ear, Hypochoeris radicata; soft chess, Bromus mollis; and Canada thistle, Cirsium arvense. The upland shrub community consists primarily of Himalayan blackberry and Scot's broom (David Evans and Associates 1991; personal observation, Parametrix 1993). The Himalayan blackberry stands are dense, almost impenetrable, and reach up to 15 ft tall. The blackberry stands have overgrown other vegetation (similar to that described above in the upland meadow community). The wet meadow portions of the largest on-site wetland are dominated almost exclusively by reed canarygrass (David Evans and Associates 1991; personal observation, Parametrix 1993). Secondary vegetation within the wet meadows includes creeping bentgrass and common velvet grass. The scrub-shrub wetland community is dominated by young willows; western crab apple, Malus fusca; red-osier dogwood, Cornus stolinifera; Douglas spirea, Spirea douglasii; and black cottonwood. The herbaceous layer consists of creeping bentgrass,creeping buttercup,Ranunculus repens, soft rush, Juncus effusus, and common horsetail, Equisetum arvense. Parametrix, Inc. 49 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin The forested wetland community is dominated by mature black cottonwoods and willows. The herbaceous and shrub layers are similar to the communities described above for the wetland shrub community. 6.3.1.2 Soils Approximately one-third of the site has either been cleared, or cleared and filled with gravel and sand from 12 to 48 inches in depth (David Evans and Associates 1991). A 4-foot-high mound of fill material covers approximately 1 acre of the site. In addition to the fill material, the site is also characterized by three soil types: Puyallup fine sandy loam (non-hydric), Woodinville silt loam (hydric), and Puget silty clay loam (hydric). Puyallup fine sandy loam is a well-drained soil formed in alluvium. This soil is found on natural terraces adjacent to streams in valleys. The A horizon ranges from fine sandy loam to very fine sandy loam and silty loam. The upper portion of the C horizon is very fine sandy loam. Non-hydric inclusions of Briscot, Newberg, Nooksack, Oridia, and Renton soils and hydric inclusions of Woodinville and Puget soils can occur. The central and eastern portion of the site were mapped as Puyallup fine sandy loam (Snyder et al. 1973). David Evans and Associates (1991) indicate that the on-site soil assessments in the eastern portion of the site are representative of this mapping unit and that the hard pan varied in thickness between 5 and 10 inches. Woodinville silt loam is a hydric soil composed of poorly drained material that formed in alluvium on stream bottoms. The A and B horizons range from silt loam to silty clay loam. Thin lenses of very fine sandy loam and loamy sand or peat occur within the horizons. Non- hydric inclusions of Puget, Snohomish, Oridia, Briscot, Puyallup, Newberg, and Nooksack soils can occur. David Evans and Associates' (1991) on-site soil investigation indicated that the western and northwestern portions of the site are representative of this mapped soil unit, and that the depth to the hard pan ranged from 3 to 14 inches. f The last mapped soil unit, Puget silt clay loam, occurs on less than one percent slopes. The A �( horizon ranges from silty clay loam to silt loam. The B horizon is silty clay loam stratified with silt loam, silty clay, and fine sand. This soil unit is mapped in a small portion of the site along the western edge. David Evans and Associates (1991) did not evaluate this soil type. A preliminary environmental site assessment indicated that the source of fill material brought onto Mitigation Banking Site 1 to fill the tributary is unknown without further investigation (Hart Crowser 1991 a). The chemical constituents of the fill material are also unknown. The-report— �\� ` w contaminated byte i e m y �is�' ''el ina ion away om a ormer i utary to localize wet an s, r r 1991 a). In addition, prior to filling of the tributary in the .earl-y-1970s, releases ro ' ' in t1fe--1ate 1960s may have entered the tributary'--Additional a ormer tributary sedimen-ts-beneath --the fill and a Parametrix, Inc. 50 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin by gdr6 eorogc curve amine the groundwater flow and direction was recommended to a e ou h the site. n assess ffe-n molder and Associates observe re was no obvious evi ence pmg or ma ion ociates 1992). The City of Renton and the project team evaluated soils at three locations on Mitigation Banking Site 1. Soil test location 1 was excavated near wetland flag M-51 (David Evans and Associates 1991) at a ground elevation of approximately 18 ft (see Figure 10). Fill occurred from the surface to an elevation of about 16 ft. Silty sand with heavy mottles mixed with fill extended to an elevation of approximately 16 ft below the surface layer of fill. Fine silty sand occurred below the silty sand. Active slumping of sediments was evident at an elevation of approximately 9 ft, indicating the depth where water was actively entering the test location. Depth of fill was estimated to be at least 2 feet. Soil test location 2 was excavated in the northwest corner of the site at a ground elevation of approximately 18 ft. Its characteristics were similar to those observed in soil test location 1 (see Figure 10). Fill occurred from the surface to an elevation of about 16 ft. Saturated silty sand mixed with mottles and fill occurred below 16 ft. At an elevation of about 11 ft the sediment was primarily silty sand. The depth of fill was estimated to be at least 5 ft. Soil test location 3 was excavated in the southeast corner of the site at a ground elevation of approximately 18 ft (see Figure 10). Fill occurred from the surface to an elevation of 16 ft. Below 16 ft was a 3/4 inch deep iron oxide layer followed by a silty fine sand fill layer. Woody debris (natural) was observed at 14 ft. Water seepage was evident at 7 ft. The depth of fill was estimated to be at least 4 ft. 6.3.1.3 Hydrology The primary source of hydrology for the existing wetlands on Mitigation Banking Site 1 is precipitation. These wetlands are in depressional areas that hold precipitation prior to evapotranspiration and infiltration. A potential secondary source of hydrology for the wetlands on Mitigation Banking Site 1 is a drainage ditch along the western and northern border of the site. Although the elevations of the wetlands and uplands appear to be considerably higher (at least 3 to 4 feet) than the ditch, high flows may overflow the banks of the ditch and enter into the large forested scrub-shrub and emergent wetland (see Figure 8). However, the volume, flow rate, and water uality in this ditch system are not known. �r .,1.� A relict tributary to Springbrook Creek, once evident w4ithin the central portion of the site (David Evans and Associates 1991), has been disturbed by fill activities since 1970. Surface water is presently diverted away from the relict tributary. It flows through the north-south drainage ditch located just inside the western boundary of the site, enters into an east-west drainage ditch, then flows east through a culvert under Metro's gravity sewer system and into the City of Renton Parametrix, Inc. 51 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin ft. The soils consisted of sandy, silty fill. A blue-gray saturated clay layer was observed at an elevation of about 10.5 ft and extended down to an elevation of about 9 ft. Concrete debris was observed at 4 ft 5 inches. No standing water was observed. The depth of fill was estimated to be approximately 9 ft. Soil test location 2 was also excavated in an upland area adjacent to an emergent wetland community at a surface elevation of approximately 16.5 ft (see Figure 11). From the surface to an elevation of 12 ft, the soil was sandy and lightly mottled with a thin silty clay layer observed at an elevation of about 14.5 ft. At an elevation of 11.5 ft the silty clay sediment was saturated and mottled. Blue clay was observed at an elevation of 10 ft followed by saturated silty clay to an elevation of 7 ft. A lens of organic material with woody debris and black wet sand was 1 observed below elevation 6.5 ft. Water was evident at elevation 5.2 ft and seepage was evident A at elevation 7 ft. Plant roots were evident as deep as an elevation 5 ft. epth of water was determine to occur at an elevation of 7 ft. e epth of fill was estimated to-Be approximately Soil test location 3 was excavated in a stand of young cottonwoods, in a wetland delineated by David Evans and Associates (1991 a), at a surface elevation of 16 ft (see Figure 11). Mottled sandy silt was evident at an elevation of 15 ft. The soils had more sandy texture above elevation 15 ft and were siltier below elevation 15 ft. An oxidized iron zone was observed at elevation 14 ft. At elevation 11 ft the soils consisted of damp clay with bright mottles. The depth of fill was estimated to be 4.5 to 5 ft. Soil test location 4 was excavated in an upland area with a surface elevation of 15.5 ft (see Figure 11). The soil consisted of sand and gravel fill with silt from the surface to an elevation of 11.5 ft. The historic A horizon composed of silty clay with mottles occurred within a 10- to 12-inch band below the fill. Below the historic A horizon was a 4-inch gleyed layer with strong mottles. Water seepage was observed at 7.5 ft. Clay was the dominant sediment to about elevation 4.5 ft. Below 4.5 ft the sediment was black wet sand. The depth of the fill was estimated to be 4 to 4.5 ft. Soil test location 5 was excavated in an upland area, had a similar profile to test location 4, and a surface elevation of 16 ft. Fill occurred from the surface to an elevation of about 13 ft (see Figure 11). This soil horizon showed no wetland characteristics. The historic A horizon was observed to 12 inches below the fill. Clay was the dominant soil below the historic A horizon. The sides of the soil test location were glistening, and seepage was evident at 8 ft. Black sand was observed at an elevation of 5.5 ft. The depth of the fill was estimated to be 3 ft. Virtually no difference was observed in the soil texture or composition within the top 3 to 4 ft between wetland and upland areas. Wetlands appear to have developed as a result of fine textured fill material gradually sealing the soils in the topographic depressions on the site, Parametriz, Inc. 54 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin resulting in soil compaction. Once compacted, the soils were able to hold rain water for a short time prior to evapotranspiration and infiltration. A preliminary environmental site assessment made by Kennedy/Jenks/Chilton (1989) indicated that a small potential existed for contamination to enter the site via groundwater. However, a site reconnaisance did not identify significant potential for environmental contamination from current or past site use. A second environmental site assessment made by Hart Crowser (1991 b) indicated that sediment samples collected from Springbrook Creek south of SW 27th between Lind Avenue and Oaksdale Avenue SW had levels of petroleum hydrocarbon identified as oil (57 mg/kg), low levels of benzene (0.06 mg/kg), toluene (0.17 mg/kg), ethylbenzene (0.087 mg/kg), xylenes (0.17 mg/kg), and low concentrations of chromium (100 mg/kg) and lead (15 mg/kg). These levels and concentrations are below the Model Toxic Control Act Method A cleanup levels, and below the WAC Sediment Criteria; no remedial activities were recommended for this area. 6.3.2.3 Hydrology The hydrology source for the existing wetlands on Mitigation Banking Site 2 is precipitation. Wetlands on this site lack an obvious inlet or outlet, and the elevation of the wetlands is at least 6 to 7 feet higher than the low flow water elevation of Springbrook Creek (10 feet). Evidence of temporary inundation in the depressional perched wetland areas was observed. Saturation to the surface and inundation to a depth of 1 inch were observed by Jones and Stokes (1993) in the emergent wetland areas. The duration of this inundation or ponding is not known. On the day of the site visit in August 1993, inundation and saturation were not observed; however, wetland hydrology was assumed based on depressional topography and marginal hydric soil characteristics. `�J _ , , • 6.3.2.4 Functional Assessment (lam°/'^ � � �s ��4� c fal`�� �„ ,►-c,. c�,l� The functional values associated with the wetlands on Mitigation Banking Site 2 were rated as low by Jones and Stokes (1993) and David Evans and Associates (1991 a) due to the size of the wetlands, lack of structural and community diversity, and an isolated and disturbed nature. Storm Water and Floodwater Control The on-site wetlands provide little, if any, flood or storm water attenuation due to their size, relative elevation to Springbrook Creek, and lack an outlet for slow release of water. Some flood or storm water that enters the site during extreme flood or storm events likely flows through the uplands and leaves the area through infiltration. Water that flows from the uplands to the wetlands leaves the area through evapotranspiration and infiltration. Parametrix, Inc. 55 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Water Quality Improvement Although the on-site wetlands are relatively densely vegetated, they occur in depressional pans and provide minimal water quality improvements because there is often little or no water flow. Hydrologic Support These wetlands have a limited seasonal hydrology. The wetlands are located in perched pan areas in isolated depressions with no obvious connection to groundwater or Springbrook Creek. These wetlands provided limited hydrologic support. Groundwater Recharge The wetlands are underlain by slowly permeable (due to compaction) consolidated fill. This factor, along with the size and isolation of the wetlands, limits the groundwater recharge value. Biological Support The wetlands provide limited biological support. The young forested and shrub canopy layers provide some cover for small mammals and birds. 6.3.3 Opportunities Opportunities provided by the mitigation banking program, or that are common to both mitigation �y banking sites, are presented below followed by specific opportunities associated with establishing wetlands on each mitigation banking site. The natural ecosystems in the Valley have been severely altered through the years by development. Reestablishing wetlands on the mitigation banking sites provides an excellent opportunity for the City to gain wetland acreage in a historic floodplain area where the added physical functions of storm water attenuation, biofiltration, and biological functions of wildlife corridors will achieve the highest value. The mitigation banking program provides an opportunity for the City to demonstrate whether wetland mitigation banking is feasible and to evaluate the technical and administrative approaches to the concept of mitigation banking. The fact that the City, as a local sponsor, is committed to establishing a mitigation banking program that is based on public and private partnerships indicates that the City is on the cutting edge of land use and resource protection conflict resolution. The mitigation banking program offers an excellent opportunity to develop the framework for relatively small-scale banking (i.e., can be developed without an entire complement of agencies involved in the implementation process). Parametrix, Inc. 56 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin and open space for passive uses within and between the neighboring wetland systems and the mitigation banking site. Flood Storage and Attenuation Mitigation Banking Site 1 provides an opportunity to increase the acreage capacity of flood storage. This site may provide storage opportunities for localized runoff from adjacent and upstream developments, as well as backwater storage from neighboring wetlands. One alternative of a flood and water quality plan being evaluated by the City would create a high -flow bypass system. This alternative would involve realigning a portion of Springbrook Creek so that flows from SW 43rd Street would flow north along the west side of Mitigation Banking Site 1, then flow east toward Springbrook Creek. Minimum flows needed to support fisheries resources would still flow through the existing Springbrook Creek channel between SW 43rd Street and SW 27th Street. Some flood storage and flow attenuation could be provided under this scenario on Mitigation Banking Site 1. If realigning a portion of Springbrook Creek becomes a preferred alternative, a design feature could be incorporated that would route the water through Mitigation Banking Site 1 before entering back into Springbrook Creek. This action would positively impact Mitigation Banking Site 1 by providing greater hydrologic support for the entire wetland system, as well as providing the hydrology necessary to support hydrophytic vegetation reestablished in the upland fill areas of the mitigation banking site (i.e., the restored wetlands). Water Quality Improvements The restored wetlands can help improve local water quality conditions by acting as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways that enter into the drainage basin in Renton. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live, work and visit in Renton. While the wetlands to be established on Mitigation Banking Site 1 have multiple values, one of the primary uses could be to improve the quality of downstream aquatic environments. Wildlife Habitat Because of its size, proximity to higher-value wetlands, and relatively greater isolation from urban development, Mitigation Banking Site 1 provides an excellent opportunity for greatly enhancing both aquatic and terrestrial wildlife habitat. By restoring a variety of wetland types, and by buffering these areas from the impacts of nearby development, a diversity of habitats will be established; that diversity will benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding upon existing natural systems and restoring habitats in areas that have been damaged by human activities ensures better survival of wildlife and provides wildlife viewing Parametrix, Inc. 58 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.3.4.2 Hydrology and Groundwater Perhaps the most challenging current constraint is the lack of seasonal depth-to-groundwater data (assumes that groundwater will be the primary source of wetland hydrology or will augment other sources of hydrology such as precipitation and surface water). There is little available on-site water to support restored wetlands. Wetlands on both sites appear to have developed as a result of surface water accumulation due to direct precipitation in slight depressional areas where, over time, finer sediments have accumulated and reduced soil permeability. Hydrologic support for wetlands on Mitigation Banking Sites 1 and 2 appears to be from local precipitation. Thus, the most significant constraint associated with establishing a hydrology on Mitigation Banking Site 2 is determining the sources of hydrology and how to manipulate the sources to meet the hydrologic needs of restored wetlands. The available information on existing hydrology for Mitigation Banking Site 1 is not adequate to develop specific site designs that could be used to prepare a bid package for restoring the uplands to wetlands. No groundwater monitoring has been done on the site to establish seasonal fluctuations which could aid in the design of created wetlands (assuming that groundwater is one potential source of hydrology for Mitigation Banking Site 1). Ideally, the level of groundwater should be measured for at least 1 year. Groundwater wells constructed of PVC pipe could be installed and monitored over the late fall, winter and spring. This additional information would allow the conceptual site design to be modified to reflect seasonal fluctuations in groundwater hydrology. An alternative and/or additional source of hydrology is the ditch that runs south to north along the western property boundary. Information on the quantity and quality of the water in this ditch is necessary before a detailed site plan can be produced and appropriate structures can be engineered. Recommendations for collecting hydrology data associated with the ditch on the western and northern boundaries of Mitigation Banking Site 1, groundwater data and other data needed to complete a detailed site design for Mitigation Banking Site 1 were provided to the City in a November 4, 1993 letter (Appendix Q. The amount and quality of hydrology information applicable to Mitigation Banking Site 2 is better than for Mitigation Banking Site 1. Base flows for Springbrook Creek have been modelled and measured (about 8 cfs). I formation is ble on mean daily precipitation and water I levels in Springbrook Creek. ne alternative for bringing water into i igztion Banking bite / involves pumping water directly from Springbrook Creek. The pumped water would provide the V ,V primary source of hydrology for the restored wetlands and would augment the hydrology in the f existing wetlands. Pumping of water requires an energy source and installation_ L ppropriate- structures; costs associated with- alternative--are--being--ev&uated. A secofida7-6rnative involves installing a well on the site west of the dike, and pumping groundwater from the well. The advantage of a groundwater well over pumping water directly from Springbrook Creek are that the quality of water is more reliable and the amount of water needed can be more readily controlled. Although groundwater was observed at an elevation of about 7 feet during the site visit in August, 1993, the depth of the well needed to capture groundwater still needs to be Parametrix, Inc. 61 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin determined. Monitoring groundwater levels in late fall, winter and spring would provide more information that can be used to modify the site plans being developed for the site and to determine, if necessary, the depth of the well needed. The disadvantages to using pump (either from Springbrook Creek or a groundwater well is that-pumps-require an energy source--afid�-� maintenance, and are-entirely-artificial.. -A third-alternative is to install a gravity fed hydraulic system in Springbrook Creek and through the dike so that water flows freely into Mitigation Banking Site 2. This alternative will require relatively extensive excavation of the existing ` 1 5 uplands to establish elevations that would match the surface elevations in Springbrook Creek during low flow periods and an engineering design that will prevent fish impingement and J entrapment. In addition, excavation of the existing uplands to elevations lower than the existing wetlands may result in dewatering of the existing wetlands. Thus, portions of the existing wetlands may also need to be excavated and/or altered to ensure that there will still be a hydrologic source for the existing wetlands, or those portions that are not altered. The site plans being developed for this site include an alternative that would result in altering existing wetlands, and an alternative that would not alter the existing wetlands. 6.3.4.3 Issues wilfi King County Drainage District No. I The King County Drainage District may place restrictions on work associated with altering dikes. For example, installing a conduit through the dike to allow high flows from Springbrook Creek into Mitigation Banking Site 2 could result in additional flood storage capacity in the Valley. The Drainage District may have concerns about the effects on the structural integrity of the dike from installation of the conduit. Thus, the possibility of altering a portion of the dike will need to be discussed with the Drainage District. ---t— LF s �� 6.3.4.4 Balanced Cut and Fill �k�� ►�J , .� G�.� ! - �QVns� �G �,� 4- Because of the depth to groundwater observed on both sites in August 1993, and the fact that filling of both sites has placed ground elevations well above original floodplain elevations, the costs to excavate and remove soils would be high. In addition, these conditions would make it costly to establish a direct hydrologic connection between restored wetlands on Mitigation Banking Site 2 and Springbrook Creek. Thus, a balanced cut-and-fill scenario is unlikely given the depth to which excavation must occur if created wetlands are to use groundwater hydrology. If groundwater hydrology is to be used, export of significant amounts of material is likely. Although the costs for excavation would be relatively high, once hydrology is obtained wetland creation success probability increases with correspondingly lower 1 scape co s .,- plant ,material cost"iiematively, if groundwater pumped via a well is used to augment hydrology for the restored wetlands on Mitigation Banking Site 2, a more balanced cut-and-fill scenario is likely, and export of soils will be less. v Parametrix, Inc. 62 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin this total, 6.77 acres are wetland, leaving a total of 7.16 acres available for establishing wetland communities and needed buffers. `A The City will need to use 5.33 acres of the total acreage to complete the compensatory mitigation required by its agreement with the Glacier Park Company. This leaves a total of 14.02 acres of a� uplands that can be restored to wetlands. However, the City's Wetland Management Ordinance \ requires that impacts to buffers must also be compensated. Therefore, a portion of the existing upland, especially around the perimeters of the sites that are closest to major thoroughfares (i.e., Oaksdale Avenue) may need to be used to create buffers. The site plans for the two sites are being developed to maximize the amount of wetland acreage. 6.4.2 Type of Mitigation Feasible for the Mitigation Banking Sites The types of feasible mitigation(i.e., functions to be restored, vegetation communities) are similar in nature for both mitigation banking sites, and are based on the review of available information on characteristics of wetlands in the Valley, the site visit, and knowledge of wetland systems in the Pacific Northwest. Restored wetlands on Mitigation Banking Sites 1 and 2 could support communities and provide functions as described below. 6.4.2.1 Communities Emergent Community Emergent communities that could be established as part of the mitigation banking program include shallow marsh and deep marsh. Wet meadow is not included because portions of the existing wetland communities are already seasonally wet meadow. Shallow marsh wetlands are characterized by relatively deep inundation in the wet season; they can tolerate dry conditions in late summer. Vegetation that is typical of these conditions can include: spikerush, Eleocharis palustris; water plantain, Alisma plantago-aquatica; slough sedge, Carex obnupta; hardstem bulrush, Scirpus acutus; small-fruited bulrush, Scirpus microcarpus; and narrowleaf burreed, Sparganium emersum; water parsley, Oenanthe sarmentosa; slender rush, Juncus tenuis; dagger- leaf rush, Juncus ensifolius. Open water habitat/deep marsh Open water components and deeper marsh habitat may also be established on the sites. In order to establish these types of communities, it may be necessary to excavate to or below groundwater depth or create this wetland community on impermeable liners. This wetland community is characterized by relatively deep inundation in the wet season; it does not typically dry out during the dry season. Vegetation that occurs within this community includes: floatingleaf pondweed, Potomageton natans; water plantain, Alisma plantago-aquatica; yellow pond lily, Nuphar polysepalum; hardstem bulrush, Scirpus acutus; and marsh speedwell, Veronica scutellata. Parametrix, Inc. 64 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Social and Aesthetic Values, and Recreation and Education Opportunities A portion of the mitigation banking sites could provide educational and passive recreational opportunities. Both sites could be considered open space. Open space, education, and recreation can all be factored into the design to relate to the positive use of a wetland by people. Wetlands are typically highly rated if they provide visual relief within a developed/developing landscape, allow access for passive recreation, and are used as outdoor classrooms. Aesthetic values of a wetland are often related to the size of the wetland/wetland system, presence of an open water component, diversity within the system, and wildlife use. 6.5 WETLAND ACREAGE POTENTIALLY ELIGIBLE WITHIN THE BLACK {' RIVER DRAINAGE BASIN FOR USE AT THE MITIGATION BANKING SITES Two primary sources of information were used to assess the size and categories of wetlands within the Black River Drainage Basin whose impacts may potentially be offset at the mitigation banking sites. The information sources were Jones and Stokes (1991) and R.W. Beck and Associates (1993). Table 1 was created using information on wetlands from their earlier documents. Table 1 shows the categories and sizes of wetlands within the Black River Drainage Basin. Approximately 37 wetlands were identified within the Black River Drainage Basin—the majority occur within the City of Renton limits (see Figure 1). Of all the inventoried wetlands, 35 have been classified as either Category 1, 2, or 3 wetlands, according to the City's Wetland Management Ordinance (City of Renton 1992). Of these, 17 wetlands (48 percent) are rated as Category 3 wetlands, 15 (43 percent) are rated as Category 2 wetlands, and 3 (9 percent) are rated as Category 1 wetlands. Assuming that the City will consider mitigation proposals for the mitigation banking sites that involve impacts to Category 1, 2, and 3 wetlands, a total of 37 wetlands are potentially eligible to use the mitigation banking sites. The 37 potentially eligible wetlands represent a total of approximately 445 acres. Estimates of wetland acreage by wetland category are provided below in Table 4. Table 5. Approximate acreage of wetlands in the Black River Drainage Basin. Wetland Category Acreage (approximate) 1 126 (28%) 2 217 (48.5%) 3 71 (16%) Uncategorized 31 (7.5%) Parametrix, Inc. 67 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin City of Renton Memorandum Date: Dec. 10, 1993 To: Scott Woodbury From: David Saxen Subject:Draft Mitigation Plan Comments I'm sorry I can't attend the meeting! The following are my comments on the draft mitigation plan, or the "working copy," to date. In general, I think the plan, which seems to consist primarily of physical and policy analysis at this point, is reasonably thorough in addressing the important issues. I have made notes pertaining to minor points in the margins of my copy, so I will comment only on the major issues here. Policy Issues For Policy Issue 1, I agree that the City should be able to use the mitigation sites. I wonder whether there is a less arbitrary limit on the extent of public mitigation allowed(50%). What is this based on? Can we determine with any accuracy what the City's mitigation needs will be in the future? Do we need to set threshold as a starting point, or can we just assess the respective needs over time? For Policy Issue 2, I agree that impacts to category 2 and 1 wetlands should not be excluded, but I do think that impacts to higher category wetlands should continue to be strongly discouraged by having much higher replacement ratios and associated costs. Such measures should effectively keep category 1 and 2 wetlands out of the program. I agree with the consultant's recommendations for Policy Issues 3, 4 and 5. For Policy Issue 6, I also think the City should seriously consider allowing enhancement, but I'm not sure how easy this will be. I wonder if the ability to mitigate impacts through enhancement would provide a cheaper alternative to developers who would otherwise use the mitigation bank. Is there any way to justify enhancement of the wetlands on the mitigation sites as a unique project(since the City's intent is to establish and preserve a continuous high quality wetland system, and also since nuisance species in these existing wetlands might pose a threat to adjacent restoration efforts)? Maybe not. In any case, the City should consider enhancement when the Ordinance is updated, which is scheduled to happen in the near future. Integration of enhancement into the Ordinance should definitely occur as part of this update, not at a later date, so than the initial mitigation bank project can benefit. Eligibility Criteria This section is fine. The chart effectively illustrates the criteria. Where do projects requiring 404 Individual permits fit in? Regulatory Requirements These will be resolved when the jurisdictional determination is made. Conditions Assessment The conditions assessment seems quite thorough. Under the Opportunities section, I didn't see much discussion of fish habitat. Is this feasible, or just not a high priority because Springbrook has limited potential for fish populations? If the project has some fisheries component or objective, it might be more attractive to certain resource agencies and environmental interests. From the analysis, deciding on a reliable source of hydrology appears to be a significant issue. For site 1 and potentially site 2, groundwater is seems like the main candidate. The main question is: how much soil do we need to excavate for the restoration effort to be successful(for the hydrology to be adequate)? How deep would we dig ideally? How deep can we afford to dig? I would think that the less we excavate, the more we compromise the success of the project. N w I strongly believe we should pursue as low maintenance a system as possible(no pumps, wells, etc.), and one that will be "self-determining" or flexible enough to adapt to the immediate conditions around it. However, this approach probably means moving more than just a few dump trucks of fill(I'll start posting "FOR SALE" signs around town). The fact that this approach may result in dewatering of adjacent wetlands, as the consultant suggests, is further justification for allowing enhancement in the Ordinance. Wetland Communities I think we should shoot for a couple different types of wetland communities to maximize the value of the site(s). By trying different things, we also see what works and what doesn't. However, if we want to maximize floodwater storage, more of the site would tend to be open water. Don't we need to use the analysis to determine what wetland functions the sites are most capable of supporting? What are the biggest needs in the Valley? What are the greatest opportunities of these sites? I would think that water quality and floodwater storage are high priorities. Mitigation Banking Feasibility Ultimately, establishing a true mitigation bank is most desirable, but probably not realistic right now($$$). In fulfilling the Glacier Park mitigation agreement(5.33 ac.), I think we should definitely create the additional 1.83 acres of wetland possible on site 2. This is a great opportunity to test the mitigation banking process on a small scale while meeting the City's obligation. In fact, it is conceivable that such a scenario might also work on bank site 1; when the City has to perform mitigation for a public project(i.e. Oakesdale extension?), it could create additional acreage to be used as credit for pending or future private impacts. This would be a way to minimize the number of phases (thus minimizing disturbances)needed to fill out bank site 1. 1 don't see developers being willing to invest in such an uncertain venture before their own projects are rolling, and unless the City commits to funding all of the restoration up front, an "incremental" banking approach seems most feasible and least risky to me. The main concerns with an incremental approach are the consecutive impacts to the site and the increased costs of construction. Yet, an incremental approach lets us apply what we learn from one phase to the next phase. This is the approach I endorse! Unrelated Questions for the Consultant Hypothetically, I wonder what the implications are of using tax increment financing to fund a mitigation bank. Although tax increment financing is currently illegal in Washington State, I believe there are a handful of cases pushing to change the law. Would this work for mitigation banking? Happy Holidays! Rk6Er+6-0 MEMO 1/4/94 TO: Scott Woodbury FROM: Lee Haro SUBJECT: Review of Draft Wetland Mitigation Bank Plan Below are some comments based on my review of the Draft Wetland Mitigation Bank Plan referenced by the page number of the draft document: Page 12: If there is to be consideration of not allowing mitigation banking to mitigate public projects,then there needs to be a determination made as to how or whether this affects the expenditure of Transportation funds that has already been made toward the City's wetlands program in the Valley. (There may be a legal requirement to pay those funds back if the City's wetlands program cannot be associated with a legally allowed transportation expenditure under State law). When the Transportation Systems Division agreed to finance the purchase of the wetlands property in the Valley, there was a clear agreement that the wetlands banking program would be available to mitigate the SW 27th Street HOV project. The Wetlands Banking Program should be careful not to violate the terms of this agreement. • The Transportation Systems Division concurs with the recommendation of this report that public projects be allowed to use the wetlands bank. Page 13: Similar to the comment on Page 12, above, if impacts to category 1 or 2 wetlands are what needs to be mitigated for a transportation project, then these will have to be allowed unless the transportation funds are paid back. • The Transportation Systems Division recommends that impacts to all types of wetlands be eligible for use of the wetlands bank. We see no reason to severly limit the City's options at this time. Page 15: I question the statement at the top of the page that "(f)ocusing the mitigation banking program on Category 3 wetlands may result in greater opportunities to retain and expand the City's economic base." If an important business or facility requires mitigation of Category 1 or 2 wetlands, then this statement would be false. Also, under GMA it is imperative that needed transportation improvements move forward for any new development to be allowed. If the transportation improvements require mitigation through the banking system of a Category 1 or 2 wetland in order to take place, then, in fact, limiting banking to Category 3 may result in lesser opportunities to retain and expand the City's economic base. • The Transportation Systems Division recommends deletion or modification of the statement at the top of page 15. Page 15: • The Transportation Systems Division agrees with option 2 to allow the bank to be used for impacts on Category 1 and 2 wetlands. If there is a real threat that this could quickly use up the available land,then perhaps a higher test can be applied to 1 and 2 before the banking site can be used,but this test has to be written such as to allow the needed transportation infrastructure to be built. Page 16: When the wetlands ordinance we being prepared it was stated that nothing in the ordinance would disallow transportation improvements as long as mitigation and/or variance procedures were met. The Transportation Systems Division agrees that a determination needs to be made as to whether the existing wetlands ordinance allows impacts to Categories 1 and 2 and recommends that the ordinance be modified to make it clear that 1 and 2 wetlands can be impacted as long as mitigation and/or variance requirements are met. Page 19: If there are alternatives that would involve impacting smaller wetlands,then that will come out in the EIS process for transportation projects. However, options for transportation facility siting are much more limited than for private developments and the City cannot afford to place additional constrictions on vital public facilities. (Note: impacting a larger wetland does not necessarily mean that a large amount of banking land will be required. The wetland impacted might be large, but the area impacted might be small.) The Transportation Systems Division agrees that the banking system must accommodate projects that impact a wetland over 1 acre in size. Also, since all development in the Valley is contingent on implementation of the Valley transportation plan, high priority has to be assigned to using the bank to mitigate transportation projects regardless of the size of the wetland impacted. Page 25: • The Transportation Systems Division strongly agrees with the recommendation that the Wetland Management Ordinance be modified (as soon as possible) to recognize enhancement as an acceptable form of compensatory mitigation. Fi.gure 5. Question. The flow chart appears to contradict the earlier recommendation that impacts on wetlands over one acre in size can be considered for banking. Page 60: • The Transportation Systems Division recommends that the Wetlands Management Ordinance be changed to recognize enhancement credits. MAIN 0AWS Cep r►�,�5 Draft City of Renton Wetland Mitgation Banking Program Y ♦ . Regulatory eats 1993 CHAPTER 1. INTRODUCTION The City of Re on is developing a wetland mitigation banking program and plan that is consistent with th City's Wetland Management Ordinance (Ordinance Number 4346) (City of Renton 1992) and omprehensive Plan(City of Renton 1993a). The mitigation banking program is a means to policy of no net loss of wetland resources in a manner that optimizes the ecological benefits while improving the cost-effectiveness of compensatory y mitigation, The wetland mitigation anking program will use larger off-site areas to mitigate for a number of independent wetland development conversions. inv a asic concept :)Ives a developer purchasing "wetland mitigation banking credits" from the City which has "banked" them for this purpose. The concept of developing a mitigation banking program resulted from three primary actions: (1) the City undertaking an inventory of its wetlands, (2) the City developing and adopting a critical areas ordinance for wetlands (City of Renton 1992) pursuant to the Growth Management Act and, (3) discussions between the City and Glacier Park, a private landholder in the Valley, on the concept of mitigation banking. During the wetlands inventory, the City found that a number of high-value we lands were still located within the Black River Drainage Basin [i.e., the Green River Valley (h6ein referred to as the Valley)]. There were also numerous lower quality wetlands that potentially reduced property owners' property values. Figure 1 shows the extent of inventoried wetlands and streams within the Black River Drainage Basin. The presence of both high and lower quality wetlands is the direct result of historic activitiea in the Valley. Originally, the Green River Valley was a flood plain wi e e high-value wetlands. Figure 2 shows the extent of natural wetlands prior to development m e Valley in 1972. During the � 1960s and 1970s, draining and filling activities for industrial, commercial, an<Some residential— , development resulted in cumulative losses of wetlands within the Valley. Figure 3 shows the , extent of fling from 1975 to 1987. Although many of the filled areas were developed, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These depressional areas developed a perched water level (water that sits on an elevated area) and eventually developed into small lower quality wetland any °f these developed p�cels were vu r owned by Glacier Park Company, a subsidiary of4uir rt g' br� Northernairoa`1�. "� -A49%ugh the City was LreftiTrg a o�ice r the protection and management of wetland resources in 1992, it an economic bas and IndusI,1-e-bI1ft4r i lands. Concurrently, Burlington Northern (BN) decided to divest = prpertl! s hef��y Park Company, a subsidiary to BN. BN also wanted to improve the market value of some of its ether Valley properties. In 1992 the Renton City Council passed a Wetlands Ordinance (City of Renton 1992) which provided opportunities to establish a wetland mitigation bank. Properties within the Valley that met certain criteria could establish and/or use an existing mitigation banking program, as long as the result was no net loss of w�etl�ands fter meeting with the City ta'4* b ' Parametrix, Inc. 1 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin 4-0M 4 > ' zv7o7C m= m O 11 m 4SH P� :v GZi _ S = -41 c� m f SW 7TH ST SW 7TH ST m m c o 33 m (n D �� m�� m {O z < SW GRPpY N 0 m n` J m� \\ A I-405 SW 16TH ST �. ................ r D D O n n Z N -qD O Z D \ m n 2 Y .. ST >; `SW .. \ Y N a \ 0 N '.:A:i::::ii?l::: \ . r000 :{:: T I 3 r { D �. { .:. . 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M1 """ "" " aos = "� " A Ltd "►F" " • "r ur I- "A A — "" ""tk" "" A " " .41 }" / "" ""�" A" A A A A A A A " 5" A A cc / ,LINDAVS " " " " " " " " " " " " " " " " " " " " " " / A%AAAA 'A k "� i z — "cn" / w "� % u i oo" t / \ rcRE OAKESDALE AV SW I �P��� iGREEK " " " " " " " " " " " " \ i 1 " " " " " " " " to "�� \ _ ` \ �jCL JACKSON SW \J � RENTON CITY LIMITS " % 1 rriuiiriiiiiriiiiiiriiiiiiiiriirrrriiriiiiiirriiiiiuriuiir✓iiiuNT ON CITY LIMITS MILL CREEK j BL\ACtK RIVER / PUMP STATION TUKWILA \ I FOREBAY Figure 2. Natural Wetlands Prior to Valley Development XX BLACK 9i� RIVER cc 9 PUMP r s Sou ce. R.W. Beck and Associates P c soc tes 1991 T S ATION T O GREEN DUWAMISW SCLE N FEET A I F T RIVER ' ER N I 0 Soo 1,000 & to discuss mitigation banking, Glacier Park ated to the City two large parcels that contained larger and relatively higher quality Category 3 wetlands. In exchange, the City allowed Glacier Park to make some smaller parcels containing lower quality Categor}r?lwetlands (less than 1 acre in size) more saleable by filling up to .99 acres of wetland on six different parcels, representing a total of 5.33 acres of fill. p The City acquired two sites totaling 44.86acres within the city limits. These sites are to be used for compensatory wetland mitigation for the 5.33 acres of fill allowed on other small parcels still under Glacier Park ownership, and for mitigation banking by other developments other than Glacier Parks'in the Valley to offset losses to lower quality wetlands. These two parcels called Mitigation Banking Site 1 and Mitigation Banking Site 2 are shown in Figure 4. Mitigation Banking Site 1 is located north of Southwest 33rd Street, south of the P-1 channel easement owned by the City of Renton, east of the Burlington Northern Rail Road, and west of Oaksdale Avenue Southwest (Sec 25, T 23N, R 4E) (see Figure 4). The site is 30.9 acres and is zoned industrial. It is bordered by developed land zoned for commercia. and industrial development along the eastern half of the southern boundary. Undeveloped commercial and industrially zoned land is adjacent to the western half of the southern boundary and to the eastern and western boundaries (David Evans and Associates 1991 a). The site consists primarily of revegetated fill material, placed approximately 20 years ago, along with 12.19 acres of relatively undisturbed upland meadow and shrubland and 18.78 acres of young forested and shrub wetlands. Mitigation Banking Site 2 is located south of Southwest 34th Street, west of Springbrook Creek, north of Southwest 39th Street, and east of Oaksdale Avenue Southwest (Sec 31, T 23N, R 5E) (see Figure 4). The site is approximately 13.93 acres and consists of 7.16 acres of upland .70 meadow and 6.77 acres of emergent, young shrub and forested wetland (David Evans and 4 .gc) ? Associates 1991 b). The site was filled over the past 20 years; the topography is relatively flat with small depressional areas. It is border d to the north by undeveloped industrial and m ► .mac r comercially zoned land. S �7 ' s Once the Citxuired the two mitigation banking sites, it assembled an interdepartmental team consisting o epresentatives from Surface Water Utility, City Plannings and Parks and Recreation to manage and develop a mitigation banking plan (City of Renton 1993b). Once the plan is finalized and approved by the City, the City will implement the plan and mitigation program. The City intends to operate, maintain, and monitor the mitigation banking sites. ' Filling of these wetlands was permitted by the U.S. Army Corps of Engineers under the Nationwide 26 permit process. Parametrix, Inc. 5 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin CHAPTER 2. GOAL, OBJECTIVES, AND POLICIES OF THE MITIGATION BANKING PROGRAM A primary goal, objectives to meet the goal, and policies that are guiding principles considered to be prudent and advantageous to achieving the objectives and goal of the mitigation banking program are presented below. 2.1 GOAL T Tile— •-nf ' create a wetland mitigation banking program that is consistent with the City's Wetland Management Ordinance (City of Renton 1992) and Comprehensive Plan(City of Renton 1993a). tAo . • , E �-- 7 2.2 OBJECTIVES 71 Objectives have been developed to help achieve this goal. The objectives, which are primarily taken from the City of Renton's Comprehensive Plan (City of Renton 1993a) and Wetland Management Ordinance (City of Renton 1992; Section 4, Chapter 32, Renton City Codes), are kisted below• U co rra e c En mmuni g ty development elopment patterns and site planning that maintain and enhance natural systems, forms, and open spaces (EN-2.0, Comprehensive Plan). Implicit in this objective is the need to define eligibility requirements for use of the mitigation banking sites and to provide a 1:1 acreage replacement on the mitigation banking sites for the 5.33 acres of impact to Category 3 wetlands, pursuant to the agreement between the City of Renton and Glacier Park. • Balance community desires for economic development with the responsibility to retain the City's wetlands base and protect environmental resources.? 1 [�, +-c. •r . • Protect and enhance water quality of surface water resources (/EN-4.0, Comprehensive Plan). • Provide for, and work toward, a regional approach to storm water management programs (EN-10.0, Comprehensive Plan). • Protect and enhance the City's rivers, major and minor creeks and intermittent stream courses (EN-5.0, Comprehensive Plan). Parametrix, Inc. 7 City of Renton - DRAFT 55-1779-07 November 11, 1993 d,tmag.pin rncrease surface storage capacity to decrease surface and flood runoff and increase groundwater recharge to maintain stream base flow. ? C • Protect the natural functions of 100-year flood plains and floodways (EN-7.0, Comprehensive Plan). • Preserve and protect wetlands for overall system functioning (EN-6.0, Comprehensive Plan). UV--> �- cl Aft4to the City's wetland resource base and retain natures, • Consolidate wetland mitigation onto the Mitigation Banking Site "L4q_ / A h � , • Protect and enhance wildlife habitat (EN-14.0, Comprehensive Plan). • Support and sustain educational, informational, and public involvement programs in the City over the long term to optimize the use, preservation, and protection of Renton's water resources (EN-11.0, Comprehensive Plan). 2.3 POLICIES Policies are guiding principles that are considered to be prudent and advantageous to achieving the objectives and goal of the mitigation banking program; policies are presented below. • Manage water resources for multiple uses including recreation, fish and wildlife, flood protection, erosion control, water supply, energy production, and open space (EN-4.1, Comprehensive Plan). • Design new development or land modifications within the 100-year flood plains to maintain natural flood storage functions and minimize hazards (EN 7.4, Comprehensive Plan). • Preserve natural surface water storage sites that help regulate surface flows and recharge groundwater (EN-8.2, Comprehensive Plan). • Utilize, maintain, and enhance the natural storm water storage capacity provided in existing significant wetlands (EN-8.10, Comprehensive Plan). • Manage cumulative effects of storm water through a combination of engineering and preservation of natural systems (EN-9.4, comprehensive Plan). • Achieve no net loss of the City's remaining wetlands (EN-6.1, Comprehensive Plan). Parametrix, Inc. 8 City of Renton -DRAFT 55-1779-07 November 11, 1993 Oftmtig pin • Provide incentives for overall net gain of wetland functions and values for new development (EN-6.7, Comprehensive Plan). • Establish and protect buffers along wetlands to facilitate infiltration and maintain stable water temperatures, provide for the biological regime, reduce the volume and velocity of runoff, and provide for wildlife habitat (EN-6.2, Comprehensive Plan). • Encourage preservation and enlargement of existing habitat areas through development incentives (EN-14.3, Comprehensive Plan). • Increase the community's understanding of the City's ecosystem and the relationship of the ecosystem to water resources (EN-11.2, Comprehensive Plan). • Encourage public access to wetlands for use when sensitive habitats are protected(EN-6.8, Comprehensive Plan). • Where appropriate, combine all critical areas and environmentally sensitive areas with recreational facilities to provide public access and trail linkages through separators (EN- 15.7, Comprehensive Plan). 7 rc(Z L_ 44 Lt AP'TE�S�a3 Parametrix, Inc. 9 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin CHAPTER 4. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANKING SITES In general, eligibility criteria for use of the mitiation banking program are base o egulato r quiremen�and o ogical consideratio �he_�eib ility criteria for the City's program would determine whic c c e Basin may be altered and subsequently compensated for at a mitigation banking site. A draft list of eligibility criteria and standards for the eligibility criteria are presented below. This list of eligibility criteria and associated standards will be used by project proponents and the City to determine whether impacts to wetlands may be compensated for at the mitigation banking sites. Meeting the standards of each criteria will be necessary before the City's mitigation banking program could be used. A simplified flow chart of the eligibility criteria is shown in Figure 5. This can be used in conjunction with the standards to determine whether mitigation banking should be considered. 4.1 ELIGIBILITY CRITERIA 1: Does the Proposed Project Comply With the City Wetland Management Ordinance (Ordinance Number 4346)? Standard Projects that have unavoidable and necessary impacts would be considered for incorporation in the wetland mitigation banking program,provided that they demonstrate compliance with all other standards of the City's ordinance. For example, use of the mitigation bank to compensate for wetland impacts would be tied to the mitigation policy of sequential mitigation actions including avoiding adverse impacts, taking affirmative measures to minimize impacts, and compensation for impacts.b Mitigation banking is basically a form of compensatory mitigation. In addition, the mitigation should be comprised of the same or higher category habitat than the altered habitat, so that similar or greater functions and values in the drainage basin are achieved [see Section 4- 32-6 (A)(2) of the Wetland Management Ordinance], and the City's standards for wetland creation and/or restoration are met. 6 This standard may need to be revised based on decisions regarding some of the policy issues in Chapter 3. Parametriz, Inc. 28 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin MITIGATION BANKING Eligibility Criteria 1: (SOULD NOT BE No DOES THE PROJECT COMPLY WITH THE CONSIDERED CITY WETLAND MANAGEMENT ORDINANCE (ORDINANCE NUMBER 4346)? Yes No Eligibility Criteria 2: IS THE PROPOSED PROJECT LOCATED WITHIN THE BLACK RIVER DRAINAGE BASIN ? Yes Eligibility Criteria 3: No IS THE IMPACTED WETLAND LESS THAN ONE ACRE,AND ISOLATED OR ABOVE THE HEADWATERS? Yes Yes Eligibility Criteria 3: IS ON-SITE MITIGATION FEASIBLE? No ELIGIBLE FOR MITIGATION BANKING PROGRAM Figure 5. Flow Chart to Determine Eligibility for Use of Mitigation Banking Program 4.2 ELIGIBILITY CRITERIA 2: Is the Proposed Project Located Within the Black River Drainage Basin? Standard The altered wetland must be located within the Black River Drainage Basin, including the Green River Valley. &AS.c ems,,�kcAvor,t� CQc,y 4.3 ELIGIBILITY CRITERIA 3: What is the Size and Category of the Wetland That May be Affected? Standard' Wetlands classified as Category 1, 2, or 3 by the City that may be altered consistent with the Wetland Management Ordinance (Ordinance Number 4346) are potentially eligible to use the mitigation banking sites. Written documentation from the Corps on the jurisdictional status(e.g., isolated, above the headwaters, less than 1 acre) of the wetland to be altered would be required. For sites with wetlands that are less than 1 acre and above the headwaters but do not have specific project plans, a copy of the jurisdictional letter from the Corps would need to be submitted to the City. For sites with wetlands that total less than 1 acre, are above the headwaters, and have specific project plans, a copy of the Nationwide Permit would need to be submitted to the City. Impacts to wetlands that require an individual permit (Section 404) from the Corps and/or Ecology(e.g.,Nationwide 26 for impacts to wetlands between 1 and 2 acres that are above the headwaters) may also be compensated for at the mitigation banking sites. A developer would need to provide the City with a copy of the appropriate permit along with written documentation that the state and federal agencies concur on using the mitigation banking sites for compensatory mitigation. 4.4 ELIGIBILITY CRITERIA 4: Is On-site Mitigation Feasible? Standard The wetland to be altered would be considered eligible for use of the mitigation banking program when: • The hydrology and ecosystem of the original wetland and those adjacent lands and/or wetlands which benefit from the hydrology and ecosystem will not be substantially damaged by the on-site loss; and This standard may need to be revised based on decisions regarding some of the policy issues in Chapter 3. Parametrix, Inc. 30 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin • On-site mitigation is not feasible (due to problems with hydrology, topography, soils, location or surroundings of the subject property, surrounding land uses); or • On-site compensation is not practical due to potentially adverse impacts from surrounding land uses; or k —_ • Exi g functional values t the proposed mitigation banking site are significantly greater than los wetland--functional values; or • Established regional goals for flood storage, flood conveyance, habitat, or other wetland function have been addressed and strongly justify location of compensatory measures at the mitigation banking sites (City of Renton 1992). 3 s, Parametrix, Inc. 31 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Table 3. Regulatory requirements needed to implement the Mitigation Banking Program. Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" Federal Compliance with Required for dredge U.S. Army Corps of Clean Water Act, (1)Nationwide permit Section 404 permits Section 404 and fill activities in Engineers (Corps); §404;33 USC § 26, <1 acre:4-6 weeks; AND Nationwide waters of the U.S. Seattle District Office 1344;33 CFR (2)Nationwide 26, >1 permits are typically including wetlands. 320 et seq.;40 acre: 8 weeks valid for a 3-year CFR Pt 230. minimum; (3) period, but may be Nationwide 27: 6-8 extended through weeks;(4) Individual negotiated permit permit:22-week conditions. minimum. NEPA process must be completed before permit c be issued. All federal permits or Corps will be the lead 42 USC§4321 et I uance of final EIS ar NEPA review(EA or National approvals issued for agency responsible for seq., 40 CFR Pt mu . st precede EIS) must be revisited Environmental construction or NEPA compliance, and 1500 et seq.; 10 issuance_of—federal only if there are(I) Policy Act(NEPA) operation of the facility compliance will be CFR 1021 (NE P permits;usually, 30 "substantial changes in trigger NEPA done through the regulations) days must elapse after the proposed action"or R7 procedures;NEPA Section 404 process. issuance before federal (II) "significant new " / 1 processes must be agency can issue the circumstances or complete before any nderlying permit. information"relevant In 1 a� S federal permits can be issued. L to environmental ^�^'C IzQ-� concerns. i np Threatened or Not a separate process; Department of the Endangered An endangered species Varies Endangered Species instead,requirements Interior through U.S. Species Act, 16 survey would take Assessments will be incorporated(if Fish and Wildlife USC § 1531 et varying amounts of applicable)into the Service w/assistance seq.; 50 CFR Pt time depending on site Section 404 permit from local jurisdiction 402 conditions. A process or Nationwide and State of Biological Assessment permit process. Washington Dept. of takes up to 180 days, or Wildlife. Department more. ESA § 7(c). A of Commerce through Biological Opinion, if the National Marine needed,takes 45 days. Fisheries Service. 50 DFR§40214(e). Historic Preservation Compliance must be Corps will be primarily Natural Historic Timing depends greatly N/A;this review Review assured through the responsible for Preservation Act, on the resources would be a component Section 404 or compliance. It must § 106, 16 USC § affected, if any, and the of other permit Nationwide Permit take into account 470 et seq.; 36 presence of opposition processes. process. comments of the U.S. CFR. §§ 60-63, and likelihood of Advisory Council on 800; 16 USC§ appeal. Historic Preservation if 469 et seq. a protected property or Not critical path. site is identified. Parametrix, Inc. 33 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" State of Washington State Environmental All state and local Probable SEPA lead Specific to each SEPA review must As with NEPA, Policy Act(SEPA) permits or approvals agency:City of Renton City/County. precede the issuance of supplemental issued for construction any state or local environmental review or operation of the permits or approvals by is required only if facility must comply 7 days. An EIS and there are(I) with the procedural associated studies "substantial changes to requirements of SEPA. generally take at least a proposal so that the A DNS, MNDS, notice 10 months to 1 year to proposal is likely to of adoption, or final complete, assuming no have significant EIS must be issued appeals. If SEPA adverse environmental before agencies issue review is "adopted," the impacts"or(II) "new permits or approvals. process can be information indicating completed in about 1 a proposal's probable month after the significant adverse completion of the environmental impacts. SEPA process. Hydraulic Project An HPA may be Washington Ch. 75.20 RCW; HPA application must Permits must Approval(HPA) required if project Department of Fisheries Ch. 220-I 10 be processed within 45 demonstrate crosses/affects fresh WAC calendar days of the "substantial progress water streams. submission of a on construction on that complete application portion of the project (,h and after issuance of a relating to hydraulic final EIS. No public approval within 2 hearing required. years of the date of issuance." HPA /[5, approvals may be granted for a period of up to 5 years. Temporary Required for Washington Dept.of Ch. 90.48 RCW; Generally,temporary None established by Modification of Water construction activities Ecology(Ecology), WAC 173-201 water quality regulation;permit Quality Criteria that temporarily violate Northwest Regional and 173-222. modification must be terms and conditions water quality criteria. Office. sought 30 days prior to generally cover May be required for - any in-water work. duration of work stream diversion ;,4)f 6, requiring the structures. � modification. Water Quality Required of any Ecology Headquarters; Federal Clean Timing of certification Not Applicable Certification(§401) applicant for a federal Central Programs; Water Act, varies. license or permit to Environmental Review Section 401;Ch. conduct any activity Section, Olympia. 173-225 WAC that may result in any discharge to surface waters. CZMP Consistency Required for permits Ecology, Shorelines 16 USC §1451 et Certification can Not applicable. Certification and licenses affecting Program,Olympia. seq.; 15 CFR generally be obtained in shoreline areas and is parts 923-930 60 days. usually considered during the Section 404 or Nationwide permit process. National Pollution Storm water pollution Ecology, Industrial Federal Clean Generally, 30 days Generally, covers Discharge Elimination control for construction Storm Water Unit. Water Act S 402; following receipt by duration of work. System(NPDES) activity that disturbs 5 40 CFR parts Ecology of Notice of Permit or more acres. 122-124 RCW Intent 90.48, 90-52; WAC 173-220 Parametrix, Inc. 34 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Statutes/ Permit/Requirement Pu ose Agency Regulations Timing Permit"Shelf Life" Water Right Permit Required for removing Ecology, Northwest Ch.90.03; State Currently averaging 2 Permit normally good and Certification any water from waters Regional Office. water to 3 years. City may for 5 years. After of the state, including code—surface already have a water water is used, water for non- water right permit to certificate is obtained cansumptve purposes. Springbrook Creek, in which is good in which case the city will perpetuity. C need to obtain a y change-in-use permit. Local nU} SUIC Shoreline Substantial Required for any City of Renton City Shoreline Permit is usually Shoreline permits are Development Permit substantial development Master Program obtained in 4-6 months. valid for 2 years. within 200 ft of a RCC 4-19 Extensions are shoreline area. possible. Sensitive Area City regulates wetlands City of Renton RCC 4-32 Process occurs upon Valid for 2 years. Regulation through sawiliweas. submittal of any Extensions are ordinance. -tl) building or land use possible. permit review and/or to obtain approval of use `2e-- �_ a and/or development of / land. Fill and Grade Permit Must be issued prior to City of Renton RCC 4-10 Grading permits for Grading must begin start of construction. projects are generally within 6 months of Does not permit issued within 4-6 permit issuance; physical construction. months. grading permit is valid See Construction for the duration of Permit. construction. Construction Permit Must be issued to start City of Renton City design Timing varies Valid from I year and Grading License construction. Issuance standards and depending upon from date of issuance. follows final review of codes completeness of plans, construction plan drawing and other City of Renton permits. Site Plan Approval Ensures proposed site City of Renton RCC 4-31-33 Generally 4 to 6 Good for 2 years with plan complies with City months. a 2-year extension, code and surrounding uses. Land Clearing and A land clearing and/or City of Renton RCC 4-9 Permits for land Valid I year from date Tree Cutting Permit tree cutting plan is clearing and tree cutting of issuance. reviewed as part of the are generally issued SEPA review and within 1 week. permitting process. Parametrix, Inc. 35 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Table 4. Anticipated changes in land use in acres (R.W Beck and Associates 1993). Land Use Springbrook Creek Panther Creek Commercial +712.9 +g 2 Multi-family residential -14.0 +96.0 High-density residential ? +229.4 ? +347.7 Medium-density residential +144.4 -62.4 Low-density residential -216.3 -91.20 Upland forest -56.3 -160.1 Upland cleared -183.1 -123.3 Lowland undeveloped -626.9 -12.3 Lake 0 -8.1 + indicates increase in land use for the particul oning - indicates decrease in land use for the particul zoning , Table 3 indicates that the anticipated changes in land use in the Springbrook Creek Drainage Basin will be toward more commercial and high- and medium-density residential housing. Commercial development currently predominates in the lowland areas in the western portion of the basin (i.e., Springbrook Creek Drainage Basin) and in the Renton commercial district. A large portion (approximately 1,510 acres) of the Springbrook Creek Drainage Basin is currently undeveloped; however, most of this area is expected to be converted to commercial and high- density residential development. Future development in the Springbrook Creek Drainage Basin will convert the existing undeveloped forest land and low-density residential areas to predominately commercial and high-density residential. The City of Renton estimates that commercial portions of the Springbrook Creek Drainage Basin will be completely developed within the next 5 to 7 years. Assuming that development occurs uniformly during this period, approximately 250 acres of land will be developed each year in the Springbrook Creek Drainage Basin (R.W. Beck and Associates 1993). Full build-out of the Panther Creek Drainage Basin is expected to occur at a lower rate estimated to be between 15 and 20 years. Thus, the amount of land developed each year in the Panther Creek Drainage Basin would be approximately 45 acres. 6.2.3 Water Ouality and Sediment Erosion Sediment loading in the Black River Drainage Basin can deteriorate the water quality and affect aquatic organisms residing in the major streams and tributaries. The major sources of sediment loading in the basin are upland erosion in the watershed and in-stream channel erosion. Upland Parametrix, Inc. 41 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin erosion is caused primarily by land-clearing activities associated with construction and development (R.W. Beck and Associates 1993). The accumulation and subsequent runoff of street dust and litter during storm events also contributes to suspended solids in urban streams. In-stream channel erosion results from erosive actions of concentrated runoff(R.W. Beck and Associates 1993). Increases in peak flow rate and duration caused by urban development and major storm and flooding events can significantly affect channel stability and increase the amount of sediment transported by the stream, unless adequate storm water control features are constructed to reduce the rate of storm water runoff from developing areas. The areas of greatest concern within the basin are upper Panther Creek and upper Springbrook Creek where extensive development is predicted and where already unstable bank conditions would be aggravated by increased flows from future development (R.W. Beck and Associates 1993). Using the future development scenarios developed by R.W.Beck and Associates(1993),the total estimated erosion for Springbrook Creek is 42 tons per year without flood controls and 0.3 tons per year with flood controls (R.W. Beck and Associates 1993); for Panther Creek, estimated erosion is 104 tons per year without flood controls and 0.7 tons per year with flood controls. Most of the residential development has occurred and will continue to occur in the eastern portion of the Panther Creek Drainage Basin. High- and low-density residential development is the primary current land use. Most of the low-density residential and undeveloped forest lands are expected to be converted to high-density and multi-family development in the future. The existing water quality of Springbrook Creek is poor (R.W. Beck and Associates 1993). Factors contributing to the present water quality include low dissolved oxygen, high numbers of fecal coliform bacteria, and high levels of turbidity, conductivity, total phosphorus, solids,metals, and ammonia. R.W. Beck and Associates (1993) indicates that the existing water quality may be affected by past structural changes in Springbrook Creek, the reduction of pollutant removal provided in wetlands, and an increase in pollutant sources. Maintaining creek flows through the city-owned wetlands, the restored wetlands in Mitigation Banking Sites 1 and 2, and in other wetlands within the basin are important steps for water quality improvement as each wetland may provide an important polishing function for the water and trap sediments, especially during high flows. 6.2.4 Flood Conditions The Renton area of the Valley has recurring flooding problems. A levee system constructed along much of the Green River in the 1950s, which included a flood gate at the confluence of the Black and Green rivers, allowed the Black River to flow into the Green River during low Green River flows. It prevented the Green River from flowing back into the Black River during periods of high Green River flows that would flood the Valley area (R.W. Beck and Associates 1991). This flood prevention mechanism was not effective because interior floodwaters could not be discharged from the Valley when the flood gate was closed due to high Green River flows. Parametrix, Inc. 42 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmug.pin • Pumping storm water from the Kent lagoon into the Green River No formal decisions have been made about the flood control alternatives presented in the most recent plans prepared by R.W. Beck and Associates (1991;1993). t 6.2.5 s Results of Review of Baseline Information and Field Assessment 1 The results of th i d sment of the two mitigation banking sites indicate that both sites contain relativel low-values asonally perched wetlands that are generally composed of cottonwood,Populus b�mifera;red alder,Alnus rubra; salmonberry,Rubus spectabilis;willow, Salix spp.; and reed canarygrass, Phalaris arundinaceae. The wildlife habitat value of the mitigation banking sites is limited by development adjacent to and near the properties; although the wildlife habitat value of the large wetland and its associated buffers on Mitigation Banking Site 1 appears to be greater than Mitigation Banking Site 2. Both sites support deciduous trees that are well developed but not fully mature. Consequently, opportunities for cavity-feeding and nesting birds, for example, are limited. The relatively young age of the forested portions of both sites and the relatively low species diversity within the plant communities limit the value of these sites for wildlife. In addition, there are few, if any, permanently wet areas on either site. The existing wetlands are seasonal in character an�3possess relatively low u�nctional values for flood water abatement and storage, and water purification. The wetlands are also poorly developed and somewhat artificial (i.e., developed on pans in isolated depressions on top of fill), and occur at elevations 5 to 9 feet higher than neighboring water bodies (e.g., Springbrook Creek) Both sites have large areas in which reed canarygrass and introduced blackberry species (Rubus discolor procera, R. lacianatus) have become established. Mitigation Banking Site 1 also has areas in which Scot's broom (Cytisus scoparius) grows. These plant species will continue to expand their ranges unless shaded by taller vegetation, removed, or otherwise controlled_ manually ` - of mic Mitigation Banking Site 2 does not show evidence 'of h an in on, but Y g g �--- - - Mitigation Banking Site 1 is frequently used as a sport off-road vehicle area, an ctivity that has resulted in significant disturbance to the landscape despite efforts by the City to r strict entry fort this purpose. ��ars di, G _ A significant amount of fill has been placed on both sites, and the depth of fill apto be as great as 10 ft in some places. This material generally has low organic content and relatively 7f,� permeable sandy soil and, although soils in the wetland areas show signs of mottles, the soils may G� 1 not have been hydric when deposited. Using a backhoe, three soil test locations were dug on Mitigation Banking Site 1 and five were dug on Mitigation Banking Site 2. The soil test locations are shown in Figures 8 and 9, and the results are presented in Figures 10 and 11. Photographs of the soil test locations are provided in Appendix B. Parametrix, Inc. 44 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmt ig.pin 6.3 SUMMARY OF MITIGATION BANKING SITE INFORMATION 6.3.1 Mitigation Banking Site 1 Mitigation Banking Site 1 is 30.97 acres and is within the 100-year Green River floodplain. Approximately one-third of the site has been cleared, or cleared and filled, over the past several years. In 1970 the site was cleared of all trees, and a tributary to Springbrook Creek that meandered through the site was filled in, creating localized wetlands (Hart Crowser 1991 a). Farming was the predominant activity on the site until the early 1980s. Three wetland communities were identified and delineated by David Evans and Associates (1991). The wetland communities typically occur in the relatively undisturbed areas and the majority of upland —� communities occur in elevated areas that have been more recently filled. The on-site wetlands are considered to be Category 3 wetlands, according to the City of Renton's Wetland Management Ordinance. hotiv 6.3.1.1 Vegetation Communities Several vegetation communities occur on the site; these include upland meadow and shrub communities, wet meadow, and scrub-shrub and forested wetland (David Evans and Associates 1991) (see Figure 8). The upland meadow communities are variable in the species composition, but in general are dominated by upland and facultative upland species. Species common to the upland meadow community include: creeping bentgrass, Agrostis stoloneifera; English plantain, Plantago lanceolata; velvet grass, Holcus lanatus; common tansy, Tanacetum vulgare; hairy cats-ear, Hypochoeris radicata; soft chess, Bromus mollis; and Canada thistle, Cirsium arvense. The upland shrub community consists primarily of Himalayan blackberry and Scot's broom (David Evans and Associates 1991; personal observation, Parametrix 1993). The Himalayan blackberry stands are dense, almost impenetrable, and reach up to 15 ft tall. The blackberry stands have overgrown other vegetation (similar to that described above in the upland meadow community). The wet meadow portions of the largest on-site wetland are dominated almost exclusively by reed canarygrass (David Evans and Associates 1991; personal observation, Parametrix 1993). Secondary vegetation within the wet meadows includes creeping bentgrass and common velvet grass. The scrub-shrub wetland community is dominated by young willows; western crab apple, Malus fusca; red-osier dogwood, Cornus stolinifera; Douglas spirea, Spirea douglasii; and black cottonwood. The herbaceous layer consists of creeping bentgrass,creeping buttercup,Ranunculus repens, soft rush, Juncus effusus, and common horsetail, Equisetum arvense. Parametrix, Inc. 49 City of Renton - DRAFT 55-1779-07 drftmtig.pin November 11, 1993 hydrogeologic survey to determine the groundwater flow and direction was recommended to determine whether contaminants have migrated through the site. In a second environmental site assessment, Golder and Associates observed that there was no obvious evidence of significant dumping or related chemical contamination (Golder and Associates 1992). The City of Renton and the project team evaluated soils at three locations on Mitigation Banking Site 1. Soil test location 1 was excavated near wetland flag M-51 (David Evans and Associates 1991) at a ground elevation of approximately 18 ft (see Figure 10). Fill occurred from the surface to an elevation of about 16 ft. Silty sand with heavy mottles mixed with fill extended to an elevation of approximately 16 ft below the surface layer of fill. Fine silty sand occurred below the silty sand. Active slumping of sediments was evident at an elevation of approximately 9 ft, indicating the depth where water was actively entering the test location. Depth of fill was estimated to be at least 2 feet. Soi st location 2 was excavated in the northwest corner of the site at a ground elevation of J b- ' approximately 18 ft. Its characteristics were similar to those observed in soil test location 1 (see Figure 10). Fill occurred from the surface to an elevation of about 16 ft. Saturated silty sand mixed with mottles and fill occurred below 16 ft. At an elevation of about 11 ft the sediment was primarily silty sand. The depth of fill was estimated to be at least 5 ft. Soil test location 3 was excavated in the southeast corner of the site at a ground elevation of approximately 18 ft (see Figure 10). Fill occurred from the surface to an elevation of 16 ft. Below 16 ft was a 3/4 inch deep iron oxide layer followed by a silty fine sand fill layer. Woody debris (natural) was observed at 14 ft. Water seepage was evident at 7 ft. The depth of fill was estimated to be at least 4 ft. 6.3.1.3 Hydrology The primary source of hydrology for the existing wetlands on Mitigation Banking Site 1 is precipitation. These wetlands are in depressional areas that hold precipitation prior to evapotranspiration and infiltration. A potential secondary source of hydrology for the wetlands on Mitigation Banking Site 1 is a drainage ditch along the western and northern border of the site. Although the elevations of the wetlands and uplands appear to be considerably higher (at least 3 to 4 feet) than the ditch, high flows may overflow the banks of the ditch and enter into the large forested scrub-shrub and emergent wetland (see Figure 8). However, the volume, flow rate, and water quality in this ditch system are not known. A relict tributary to Springbrook Creek, once evident within the central portion of the site (David Evans and Associates 1991), has been disturbed by fill activities since 1970. Surface water is presently diverted away from the relict tributary. It flows through the north-south drainage ditch located just inside the western boundary of the site, enters into an east-west drainage ditch, then flows east through a culvert under Metro's gravity sewer system and into the City of Renton Parametrix, Inc. 51 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin wetlands. Once water enters into the City of Renton wetlands, it is retained and leaves the site through evapotranspiration and infiltration. There is no direct outlet (i.e., culvert or day-lighted stream or ditch) from the City of Renton wetlands to Springbrook Creek. Under current conditions,there is no surface connection between the wetlands on Mitigation Banking Site 1 and Springbrook Creek. 6.3.1.4 Functional Assessment David Evans and Associates (1991) evaluated the wetland communities for five functions. In general,the functional values associated with the existing wetlands were rated as moderate-to-low. Storm water and Floodwater Control 6 Y A three wetlands have a seasonal hydroperiod and over 30 percent woody plant cover, factors tha eimportant to impeding surface flows from surrounding commercial and industrial facilities. The overall value associated with slowing surface sheet flow is less for the scrub-shrub wetlands because of their small size. The forested scrub-shrub and emergent wetland is larger and has a discernable drainage corridor along its western and northern borders. Water Quality Improvement The three wetlands contribute minimally to improving downstream water quality and filtering of contaminants and other toxicants that may be in receiving waters from adjacent non-point and point source pollutants. The wetlands' usefulness in providing significant water quality function is limited by the ditch along the western and northern borders of the site. The ditch itself provides limited water purification function due to the lack of emergent vegetation. Hydrologic Support All three wetlands had characteristics that indicated ponding and a seasonal hydrology. The smaller scrub-shrub wetlands are in topographic depressions and are somewhat limited in their ability to provide hydrologic support. The larger forested scrub-shrub and emergent wetland is next to an open drainage system along the western and northern boundaries of the site and may contribute to the hydrologic support of adjacent and downstream wetlands and Springbrook Creek. Groundwater Recharee The three wetlands are underlain by slowly permeable consolidated till and appear to be temporarily or seasonally saturated. These factors limit their ability to provide significant groundwater recharge functions. Parametriz, Inc. 52 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin �--� ��-�- c.,tlaoQr��►-may Biological Support All three wetland communities have somewhat limited species and structural diversity. o or water-dependent species and few indications of animals, other than song birds, w e observed by David Evans and Associates (1991) or Parametrix (1993). The large scrub-s emergent wetland is more diverse and has greater structural diversity than the smaller scrub-shrub wetlands. It may provide cover and nesting or perching sites for small mammals and birds. The' dry upland and seasonally wet meadow areas provide habitat for small mammals that are prey to larger mammals (e.g., coyote) and raptors (e.g., red-tailed hawks). 6.3.2 Mitigation Banking Site 2 no} 4), �virb� GnAlYM u,ra lite Mitigation Banking Site 2 is 13.93 acres. The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, and a fairly large young forested wetland community consistingusr,,�X,�t�6� primarily of cottonwoods and shrubs (see Figure 9). The site was filled within the past 20 years, NJ{,,,dS and with a few minor exceptions, the topography is relatively flat with small depressions formed w, do-t,,IJ by heavy equipment conducting grading work. Three wetlands were identified and delineated by W wsry David Evans and Associates (1991a) ranging from 0.05 to 2.39 acres. Two of the wetlands are / classified as palustrine scrub-shrub wetlands and the third is classified as a palustrine forested wetland. The wetlands are considered to be Category 3 wetlands, according to the City of Renton's Wetland Management Ordinance. 6.3.2.1 Vegetation Community The young forested community is dominated in a canopy layer by black cottonwoods and willows. Black cottonwood and willow saplings comprise the majority of the shrub canopy along with salmonberry and Himalayan blackberry. Herbaceous cover within the forested community is sparse, but grasses and forbs occur occasionally. The emergent wetlands are shallow depressions in a topographically level upland area and are dominated by bentgrass; foxtail, Alopecurus geniculatus; soft rush;and reed canarygrass. Upland forbs and grasses include clover, Tripholim repens; Kentucky bluegrass, Poa pratensis; tall fescue, Festuca arundinacea; quackgrass, Agropyron repens; and hairgrass, Aira caryophyellea. 6.3.2.2 Soils The soils on the site are mapped as Woodinville silt loam, a hydric soil (Snyder et al. 1973). However, the majority of the site consists of fill material. The site has been driven on and the compactions, coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in the areas where wetlands have formed on top of the fill. Five soil test locations were evaluated at Mitigation Banking Site 2. Soil test location 1 was excavated on a topographic high point in an upland area adjacent to Springbrook Creek at an elevation of about 19.5 ft. In general, the soils were uniform from the surface to an elevation of about 10.5 Parametrix, Inc. 53 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin If the mitigation banking program is implemented, the City will have an opportunity to fulfill the policy of no net loss of wetlands. The City of Renton's policy of no net loss of wetland acreage, can be realized by protecting higher value wetlands, and requiring estoration of disturbed wetlands or creation of new wetlands to offset losses that are unavoidable 5�6�o�1 4��8 (City of Renton Ordinance Number 4336, Section 4, Chapter 32). In meeting the policy of no net loss of wetland resources, the City encourages creation of higher category wetlands than the altered wetland, and allows multiple or cooperative compensation for one project within the same drainage basin. Finally, the City believes that establishing larger contiguous wetlands for the purposes of a mitigation banking program will meet the policy of no net loss by providing larger, consolidated, and higher quality wetlands rather than small, scattered, isolated, and low-quality wetlands. � The City of Renton currently owns several parcels of property that contain wetlands (see Figure 0 ). The intent of the City is to retain the natural features of these parcels as open space and natural resource corridors. The wetlands on these parcels are currently providing some of th recognized functions of wetlands, i lud' flood storage, ldlife habitat, water quality improvement, and groundwater rech e. Restormg on the two mitigation banking sites would prove an oppo ty o add acreage and quality to the wetland resource base within the City. The City esires o use the mitigation banking program as an opportunity to reverse the nd of wetland to and begin a positive trend toward wetland gains by restoring some of the oric wetland sys ms in the Black River Drainage Basin. itigation b ng program provides an opportunity for the City to consolidate some wetland tigation in a ance of wetland impacts. The consolidated wetland mitigation approach also provides oppo ties for achieving the wetland mitigation banking program goals and objectives, and the City' Wetland Management Ordinance when on-site options are not feasible. The mitigation b ing program concept can benefit both the community and users of the bank as well as the atural resources that use and/or depend on wetland systems. The bank program %, Preplanne rovides opportunity for individual users where the details of wetland compensation are - J , constructed, and maintained by the City, and where the costs to the developer have `Z-�been d rmined. 6.3.3.1 Opportunit' sMitigation Banking Site 1 Protection of Wetlands and Increased Functional Value / Mitigation Banking Site 1 is located west and south of large, high-value City-owned wetlands (Category 1, wetlands based on the City's rating system). The proximity of Mitigation Banking Site 1 to high-quality wetlands provides an opportunity for increased protection of restored wetlands from other uses and destructive human activities. Proximity of this site to higher-quality wetlands also provides an opportunity for increased functional values of restored and existing wetlands, such as providing connections between wetland systems, and providing habitat corridors Parametrix, Inc. 57 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin and open space for passive uses within and between the neighboring wetland systems and the mitigation banking site. Flood Storage and Attenuation Mitigation Banking Site 1 provides an opportunity to increase the acreage capacity of flood storage. This site may provide storage opportunities for localized runoff from adjacent and upstream developments, as well as backwater storage from neighboring wetlands. One alternative of a flood and water quality plan being evaluated by the City would create a high-flow bypass system. This alternative would involve realigning a portion of Springbrook v Creek so that flows from SW 43rd Street would flow north along the west side of Mitigation Banking Site 1, then flow east toward Springbrook Creek. Minimum flows needed to support fisheries resources would still flow through the existing Springbrook Creek channel between SW ?43rd Street and SW 27th Street. Some flood storage and flow attenuation could be provided under this scenario on Mitigation Banking Site 1. If realigning a portion of Springbrook Creek becomes a preferred alternative, a design feature could be incorporated that would route the water through Mitigation Banking Site 1 before entering back into Springbrook Creek. This action would positively impact Mitigation Banking Site 1 by providing greater hydrologic support for •the entire wetland system, as well as providing the hydrology necessary to support hydrophytic vegetation reestablished in the upland fill areas of the mitigation banking site (i.e., the restored � wetlands). Water Quality Impr vements , The restored wetlands can help improve local water quality conditions by acting as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways that enter into the drainage basin in Renton. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live, work and visit in Renton. While the wetlands to be established on Mitigation Banking Site 1 have multiple values, one of the primary uses could be to improve the quality of downstream aquatic environments. Wildlife Habitat Because of its size,proximity to higher-value wetlands, and relatively greater isolation from urban development, Mitigation Banking Site 1 provides an excellent opportunity for greatly enhancing both aquatic and terrestrial wildlife habitat. By restoring a variety of wetland types, and by buffering these areas from the impacts of nearby development, a diversity of habitats will be established; that diversity will benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding upon existing natural systems and restoring habitats in areas that have been damaged by human activities ensures better survival of wildlife and provides wildlife viewing Parametrix, Inc. 58 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin opportunities. The concept of habitat corridors also enhances the value of the area for aquatic and terrestrial wildlife. Public Access and Education The City of Renton recreation plans ( rt ' ' d show trails in close proximity to ......... ...........:.P :::::::.: P tY ::::::..........::::::::::.............. Mitigation Banking Site 1. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban storm water quality, etc., and could be offered by interpretive signage and printed materials. Planned trails and wetland and wildlife observation points could provide opportunities for public enjoyment of Renton environments. The wetland environment in Renton could become a favorite place to recreate and learn, particularly us d b elementary, secondary, and higher learning institutions in the community. Located South Seattle Community College, ese wetlands could be the su iect of further study by interested wetland research scientists ter the coming,decades. 6.3.3.2 Opportunities in MitigationBa king Site 2 Improved Flood Control Mitigation Banking Site 2 has the capacity to provide flood storage. Based on the size of the site, along with elevation information, the site has the potential to accommodate approximately 14 to 30 acre feet of storage (depending on the elevations of the restored wetlands and whether existing wetlands are excavated). A flood-storage function could be established by installing a conduit through the dike at an elevation designed for a particular storm event (e.g., 2- or 5-year event). Flood waters would then enter Mitigation Banking Site 2 from Springbrook Creek, be stored and attenuated in the restored and existing wetlands and reenter Springbrook Create at an engineered and constructed outlet structure at the northeast corner of the site. A small proportion of flood water would be lost due to evapotranspiration and infiltration. This would reduce impacts to downstream areas from storm runoff originating in the Valley. This flood storage improvement can also provide multiple benefits, such as wildlife habitat. Water Quality Improvements By acting as biological filters to remove sediments, certain nutrients, and other water pollutants t `from the drainageways, the restored wetlands can help improve local water quality conditions in on. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live, work and visit in Renton. While the wetlands to be established on Mitigation Banking Site 2 have multiple values, one of the primary uses could be to improve the quality of downstream aquatic environments. Parametrix, Inc. 59 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin Wildlife Habitat and Corridor Mitigation Banking Site 2 is next to Springbrook Creek, a ditched and diked channel. The mitigation banking site's proximity to Springbrook Creek offers an opportunity to provide aquatic and terrestrial wildlife linkages to other wetlands, water bodies, and open-space areas, as well as downstream benefits to fish and wildlife. Another identified opportunity is to have some wet meadow areas that become relatively dry in late spring and summer for small mammal shelter and foraging. These smaller mammals in turn act as a food source for predatory birds, such as red-tailed hawks, and larger mammals. Providing this type of wetland habitat, along with other wetland habitats(e.g., open water aquatic bed), increases the overall diversity and features inherent in a higher quality wetland system. Finally, the Renton community can be enhanced by restoring a variety of wetland types, linking them to other City-owned, high-quality wetlands, and managing the City-owned wetlands as a connected system. Public Access and Education The City of Renton recreation plans + ' ` ort show trails along Mitigation ............. Banking Site 2. These trails would provide opportunities for both passive recreation and 1%, education. Passive recreation would include bird watching, walking, bicycling, and photography. ducation could focus on wildlife, wetlands, salmonid biology, urban stormwater quality, etc., d could be offered by interpretive signage and printed materials. Planned trails and wetland and wildlife observation points could provide numerous opportunities for public enjoyment of Renton environments. The wetland environment in Renton could become a favorite place to recreate and learn, particularly if used by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington and South Seattle Community College, these wetlands could be the subject of further study by interested wetland research scientists over the coming decades. 6.3.4 Constraints Constraints associated with restoring both mitigation banking sites are presented below. Where appropriate, differences in constraints for each site are identified. 6.3.4.1 Enhancement Credits The City of Renton's Wetland Management Ordinance does not recognize enhancement as an acceptable form of compensatory mitigation. There are approximately 10 to 15 acres of existing wetlands that could be enhanced and used for mitigation banking if the ordinance was modified in the future. (See Chapter 3, Policy Issue 6.) to ` Parametrix Inc. I ' — 60 City of Renton - DRAFT 55-1779Z November 11, 1993 drftmtigpin / Gt/w' � 1 6.3.4.2 Hydrology and Groundwater Perhaps the most challenging current constraint is the lack of seasonal depth-to-groundwater data (assumes that groundwater will be the primary source of wetland hydrology or will augment other sources of hydrology such as precipitation and surface water). There is little available on-site water to support restored wetlands. Wetlands on both sites appear to have developed as a result of surface water accumulation due to direct precipitation in slight depressional areas where, over time, finer sediments have accumulated and reduced soil permeability. Hydrologic support for wetlands on Mitigation Banking Sites 1 and 2 appears to be from local precipitation. Thus, the most significant constraint associated with establishing a hydrology on Mitigation Banking Site 2 is determining the sources of hydrology and how to manipulate the sources to meet the hydrologic needs of restored wetlands. The available information on existing hydrology for Mitigation"Banking Site 1 is not adequate to develop specific site designs that could be used to prepare a bid package for restoring the uplands to wetlands. No groundwater monitoring has been done on the site to establish seasonal fluctuations which could aid in the design of created wetlands (assuming that groundwater is one ^ potential source of hydrology for Mitigation Banking Site 1). Ideally, the level of groundwater should be measured for at least 1 year. Groundwater wells constructed of PVC pipe could be 'installed and monitored over the late fall, winter and spring. This additional information would allow the conceptual site design to be modified to reflect seasonal fluctuations in groundwater hydrology. An alternative and/or additional source of hydrology is the ditch that runs south to north along the western property boundary. Information on the quantity and quality of the water in this ditch is necessary before a detailed site plan can be produced and appropriate structures can be engineered. Recommendations for collecting hydrology data associated with the ditch on the western and northern boundaries of Mitigation Banking Site 1, groundwater data and other data needed to complete a detailed site design for Mitigation Banking Site 1 were provided to the City in a November 4, 1993 letter (Appendix Q. The amount and quality of hydrology information applicable to Mitigation Banking Site 2 is better than for Mitigation Banking Site 1. Base flows for Springbrook Creek have been modelled and measured (about 8 cfs). Information is also available on mean daily precipitation and water levels in Springbrook Creek. One alternative for bringing water into Mitigation Banking Site 2 involves pumping water directly from Springbrook Creek. The pumped water would provide the primary source of hydrology for the restored wetlands and would augment the hydrology in the existing wetlands. Pumping of water requires an energy source and installation of appropriate structures; costs associated with this alternative are being evaluated. A second alternative involves installing a well on the site west of the dike, and pumping groundwater from the well. The advantage of a groundwater well over pumping water directly from Springbrook Creek are that the quality of water is more reliable and the amount of water needed can be more readily controlled. Although groundwater was observed at an elevation of about 7 feet during the site visit in August, 1993, the depth of the well needed to capture grouvn�ldl�water still needs to be Parametrix, Inc. 61 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin _ �-X/J [7t determined. Monitoring groundwater levels in late fall, winter and spring would provide more information that can be used to modify the site plans being developed for the site and to determine, if necessary, the depth of the well needed. The disadvantages to using pump (either from Springbrook Creek or a groundwater well is that pumps require an energy source and maintenance, and are entirely artificial. A third alternative is to install a gravity fed hydraulic system in Springbrook Creek and through the dike so that water flows freely into Mitigation Banking Site 2. This alternative will require relatively extensive excavation of the existing uplands to establish elevations that would match the surface elevations in Springbrook Creek during low flow periods and an engineering design that will prevent fish impingement and entrapment. In addition, excavation of the existing uplands to elevations lower than the existing wetlands may result in dewatering of the existing wetlands. Thus, portions of the existing wetlands may also need to be excavated and/or altered to ensure that there will still be a hydrologic source for the existing wetlands, or those portions that are not altered. The site plans being developed for this site include an alternative that would result in altering existing wetlands, and an alternative that would not alter the existing wetlands. 6.3.4.3 Issues with King County Drainage District No. 1 The King County Drainage District may place restrictions on work associated with altering dikes. For example, installing a conduit through the dike to allow high flows from Springbrook Creek into Mitigation Banking Site 2 could result in additional flood storage capacity in the Valley. The Drainage District may have concerns about the effects on the structural integrity of the dike from installation of the conduit. Thus, the possibility of altering a portion of the dike will need to be discussed with the Drainage District. 6.3.4.4 Balanced Cut and Fill rj( Because of the depth to groundwater observed on both sites in August 1993, and the fact that filling of both sites has placed ground elevations well above original floodplain elevations, the costs to excavate and remove soils would be high. In addition, these conditions would make it costly to establish a direct hydrologic connection between restored wetlands on Mitigation Banking Site 2 and Springbrook Creek. Thus, a balanced cut-and-fill scenario is unlikely given the depth to which excavation must occur if created wetlands are to use groundwater hydrology. If groundwater hydrology is to be used, export of significant amounts of material is likely. Although the costs for excavation would be relatively high, once hydrology is obtained wetland creation success probability increases with correspondingly lower landscape costs (i.e., plant material costs). Alternatively, if groundwater pumped via a well is used to augment hydrology for the restored wetlands on Mitigation Banking Site 2, a more balanced cut-and-fill scenario is likely, and export of soils will be less. e�� �— ? Parametrix, Inc. 62 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.3.4.5 Urban Development Urban development is in close proximity to both sites. Lots zoned for industrial uses are directly north of Mitigation Banking Site 2. A major thoroughfare, Oaksdale Avenue, is directly west of the site. Mitigation Banking Site 1 is relatively more isolated from urban development, and will have only a portion of a Oaksdale Avenue along one of its boundaries once construction of Metro's gravity sewer system is complete. Nevertheless, this site has adjacent development along its southern boundary, and further development in this area is likely to occur. Existing and future urban development are not significant constraints; a reality that needs to be considered when deciding what types of wildlife functions realistically be expected. A 6.3.4.6 Existing Potential Seed Bank The current soil seed bank on both sites may not contain some of the important plant species (e.g., rushes, sedges, bulrushes, bur-reed, cattail, water parsley, water lily) which might be used in the mitigation banking wetlands. Existing plant communities express what is likely held in the seed bank (i.e., black cottonwood, red alder, salmonberry, reed canarygrass, and Himalayan blackberry). However, it is reasonable to suggest that the historic seed bank (prior to filling) contains some of the important plant species that would add structural and species diversity to the mitigation bank. For example, a review of some historic aerial photographs taken of the tributary to Springbrook Creek before it was fill indicates that some seeds from plant species that provide habitat structure and diversity. 6.3.4.7 Soils Little wetland soil (e.g., peats or muck) is available on either site to use in construction of new wetlands. However, if the clay found within soil test location 2 on Mitigation Banking Site 2 is abundant over the site, it may be suitable for lining some restored wetlands. However, an appropriate planting medium, such as topsoil, may need to be imported to the sites to allow the roots of plants to become established. 6.4 ACREAGE AND TYPE OF MITIGATION FEASIBLE FOR THE MITIGATION BANKING SITES 6.4.1 Acreage of Mitigation Feasible on the Mitigation Banking Sites Combined, both mitigation banking sites can provide a total 19.35 acres of restored wetlands. Specifically, Mitigation Banking Site 1 consists of 30.97 acres of land. Of this total, 18.78 acres are considered to be wetland, leaving a total of 12.19 acres of upland available for establishing wetlands and buffers. Mitigation Banking Site 2 consists of a total of 13.93 acres of land. Of Parametrix, Inc. 63 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Water Quality Improvement Wetlands can improve water quality by slowing the movement of water and causing sediments and any associated pollutants to settle and be deposited on wetland substrates. Currently, the source of hydrology for the existing wetlands on both mitigation banking sites is precipitation. Restoring wetlands on both sites requires a water source to be identified and routed into the restored wetland communities. The quality of water that may enter Mitigation Banking Site 1 from upstream sources or from the ditch along the western boundary of the site could be improved (this assumes that there is a water quality issue associated with upstream waters) by passing the water through the restored and existing wetlands. Water quality problems in Springbrook Creek have been documented and described in the East Side Green River Watershed Plan (R.W. Beck and Associates 1991) and the Black River Drainage Basin Draft Water Quality Management Plan (R.W. Beck and Associates 1993). If the source of hydrology for the restored wetlands on Mitigation Banking Site 2 is obtained by using water from Springbrook Creek, the wetlands can potentially provide a water quality improvement function. Even if the source of hydrology for the restored wetlands is groundwater, Mitigation Banking Site 2 can still provide water quality improvement functions if a system is designed to allow flood waters to enter the site. The surface of leaves, stems, and litter from dense herbaceous and woody wetland vegetation restored on the site can physically catch and filter suspended sediments. Wetland vegetation provides a large surface area for the attachment of bacteria, which are the primary mechanism for nutrient reduction. In addition, certain toxins can be broken down by plant metabolic processes; other toxins remain within the plant until the plant decomposes. Plants that decompose slowly during months with relatively high water flows are excellent sources of biofiltration. Smaller sediment particles may also settle in standing open water/aquatic beds, providing additional improvements to water quality. Wildlife Habitat and Downstream Biological Support Providing ecological habitat is among the easiest functions to restore in wetlands and their buffers (Ecology 1993). Components of high-quality habitat that would be established on the Mitigation Banking Sites include: high structural diversity [i.e., emergent, shrub, and forested (existing) canopy layers for birds]; relatively undisturbed corridors between the site, City of Renton Wetlands, and Springbrook Creek; a relatively high diversity of native plants; and intermittent and seasonal open water/deep marsh components. Several of the plant species listed in Section 6.4.2.1 are known to provide important wildlife values. For example, slough sedge seeds provide food for waterfowl (especially pintail and mallard ducks, and shovelers)and for soras, dowitchers, grouse, juncos, and sparrows. Parametrix, Inc. 66 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.6 FEASIBILITY OF MITIGATION BANKIN PROGRAM The feasibility of the mitigation banking conc latively uncomplicated. After areas are acquired and wetlands restored, created, o nhance , the acreage and/or functional value o -�_ the created, restored, and/or enhanced etlan s easured and a total number of mitigation credits are established for the bank (For 91). As wetland development in the Black River Drainage Basin is permitted by the City, existing acreage and functions of wetlands that would be lost are measured by the same method used to assess acreage and function of the banked wetland mitigation, and debits are made to the bank, reducing its credit balance. The terms by which credits are traded for units of permitted wetland loss—the trading ratio—are typically set by the lead regulatory agency to achieve no net loss of wetlands or wetland function. Eventually, all of the credits are withdrawn from the bank to compensate for wetland losses, and a new bank can be established by rehabilitating or creating new wetland habitat (Short 1988). Wetland mitigation banking was developed as an administrative strategy to deal with compensation for unavoidable project-related resource losses. This form of mitigation differs from concurrent compensatory mitigation in that the off-site mitigation is not necessarily exclusive to one specific project and the mitigation occurs in advance of project impacts (Figure 12). Mitigation banking is intended to involve only those habitat protection, creation, or improvement measures taken expressly to compensate for habitat losses associated with future development actions (Short 1988). Mitigation banking requires that a plan be conceived and implemented that identifies the location of wetland resources, characterizes wetland functions, develops an overall scheme for wetland resource management prior to any proposal for wetland alteration, and identifies the implementation process for using the mitigation banking program. Short (1988) describes mitigation banking as follows: ...mitigation banking is similar to maintaining a bank account. A developer undertakes measures to create, restore, or preserve fish and wildlife habitat in advance of an anticipated need for mitigation for future project construction impacts. The benefits attributable to these measures are quantified, and the developer receives mitigation credits from the appropriate regulatory and/or planning agencies. These credits are placed in a mitigation bank account from which withdrawals can be made. When the developer proposes a project involving unavoidable losses of fish and wildlife resources, the losses (debits) are quantified using the same method that was used to determine credits, and a withdrawal equal to that amount is deducted (credited) from the bank. This can be repeated as long as mitigation credits remain available in the bank. An alternative off-site mitigation program to mitigation banking is concurrent compensatory mitigation. Concurrent off-site mitigation allows a project proponent to develop a project site and mitigate concurrently for impacts to wetlands at a selected site within the same drainage basin, or other defined area. Parametrix, Inc. 68 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin $ 4 Draft Pew City of Denton Wetland Mitgation Banking Program 1993 CHAPTER 1. INTRODUCTION The City of Renton is developing a wetland mitigation banking program and plan that is consistent with the City's Wetland Management Ordinance (Ordinance Number 4346) (City of Renton 1992) and Comprehensive Plan(City of Renton 1993a). The mitigation banking program is a means to comply with the policy of no net loss of wetland resources in a manner that optimizes the ecological benefits while improving the cost-effectiveness of compensatory mitigation. The wetland mitigation banking program will use larger off-site areas to mitigate for a number of independent wetland development conversions. The basic concept involves a developer purchasing "wetland mitigation banking credits" from the City which has "banked" them for this purpose. The concept of developing a mitigation banking program resulted from three primary actions: (1) the City undertaking an inventory of its wetlands, (2) the City developing and adopting a critical areas ordinance for wetlands (City of Renton 1992) pursuant to the Growth Management Act and, (3) discussions between the City and Glacier Park, a private landholder in the Valley, on the concept of mitigation banking. During the wetlands inventory, the City found that a number of high-value wetlands were still located within the Black River Drainage Basin [i.e., the Green River Valley (herein referred to as the Valley)]. There were also numerous lower quality wetlands that potentially reduced property owners' property values. Figure 1 shows the extent of inventoried wetlands and streams within the Black River Drainage Basin. The presence of both high and lower quality wetlands is the direct result of historic activities in the Valley. Originally, the Green River Valley was a flood plain with relatively high-value wetlands. Figure 2 shows the extent of natural wetlands prior to development in the Valley in 1972. During the 1960s and 1970s, draining and filling activities for industrial, commercial, and some residential development resulted in cumulative losses of wetlands within the Valley. Figure 3 shows the extent of filling from 1975 to 1987. Although many of the filled areas were developed, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These depressional areas developed a perched water level (water that sits on an elevated area) and eventually developed into small lower quality wetlands. Many of these undeveloped parcels were owned by Glacier Park Company, a subsidiary of Burlington Northern Railroad. Although the City was drafting an ordinance for the protection and management of wetland resources in 1992, it was also concerned with retaining an economic base and industrial lands. Concurrently, Burlington Northern (BN) decided to divest some properties held by the Glacier Park Company, a subsidiary to BN. BN also wanted to improve the market value of some of its other Valley properties. In 1992 the Renton City Council passed a Wetlands Ordinance (City of Renton 1992) which provided opportunities to establish a wetland mitigation bank. Properties within the Valley that met certain criteria could establish and/or use an existing mitigation banking program, as long as the result was no net loss of wetland; After meeting with the City Parametrix, Inc. I City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin to discuss mitigation banking, Glacier Park donated to the City two large parcels that contained larger and relatively higher quality Category 3 wetlands. In exchange, the City allowed Glacier Park to make some smaller parcels containing lower quality Category wetlands (less than 1 acre in size) more saleable by filling up to .99 acres of wetland on six different parcels, representing a total of 5.33 acres offill.' The acquired two�sites totaling 44.80 acres within the city limits. These sites are to be used for compensatory wetland mitigation for the 5.33 acres of fill allowed on other small parcels still under Glaciek Park ownership, and for mitigation banking by other developments6ther than Glacier Pazkin the Valley to offset losses to lower quality wetlands. These two parcels,called Mitigation Banking Site 1 and Mitigation Banking Site 2,are shown in Figure 4. Mitigation Banking Site 1 is located north of Southwest 33rd Street, south of the P-1 channel easement owned by the City of Renton, east of the Burlington Northern Rail Road, and west of Oaksdale Avenup Southwest (Sec 25, T 23N, R 4E) (see Figure 4). The site is 0 �b �"�' • acres and is zoned[ tistrial) It is bordered by developed land zoned focommerci and ./a• industrial development ong the eastern half of the southern boundary. Undeveloped commercial f� 1 JNGUSfWr1, and industrially zone land is adjacent to the western half of the southern boundary and to the eastern and western boundaries (David Evans and Associates 1991a). The site consists primarily of revegetated fill material, placed approximately 20 years ago, along with 12.19 acres of relatively undisturbed upland meadow and shrubland and 18.78 acres of young forested and shrub wetlands. Mitigation Banking Site 2 is located south of Southwest 34th Street, west of Springbrook Creek, north of Southwest 39th Street, and east of Oaksdale Avenue Southwest (Sec 31, T 23N, R 5E) (see Figure 4). The site is approximately 13.93 acres and consists of 7.16 acres of upland meadow and 6.77 acres of emergent, young shrub and forested wetland (David Evans and Associates 1991b). The site was filled over the past 20 years; the topography is relatively flat with small depressional areas. It is bordered to the north by undeveloped industrial and (commercially zoned land. `,. —yr Once the City acquired the two mitigation banking sites, it assembled an interdepartmental team consisting of representatives from Surface Water Utility, �Planning, and Parks and Recreation to manage and develop a mitigation banking plan (City of Renton 1993b). Once the plan is finalized and approved by the City, the City will implement the plan and mitigation program. The City intends to operate, maintain, and monitor the mitigation banking sites. ' Filling of these wetlands was permitted by the U.S. Army Corps of Engineers under the Nationwide 26 permit process. Parametric, Inc. 5 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin CHAPTER 2. GOAL, OBJECTIVES, AND POLICIES OF THE MITIGATION BANKING PROGRAM A primary goal, objectives to meet the goal, and policies that are guiding principles considered to be prudent and advantageous to achieving the objectives and goal of the mitigation banking program are presented below. ; 4- **A,. , s b-**--4 + 2.1 GOAL The goal is the purpose toward which the mitigation banking program is directed. The City of Renton's overall goal is to create a wetland mitigation banking program that is consistent with the City's Wetland Management Ordinance (City of Renton 1992) and Comprehensive Plan(City of Renton 1993a). 41&^ N/- 2.2 OBJECTIVES Objectives have been developed to help achieve this goal. The objectives, which are primarily taken from the City of Renton's Comprehensive Plan (City of Renton 1993a) and Wetland Management Ordinance (City of Renton 1992; Section 4, Chapter 32, Renton City Codes), are listed below: • Encourage community development patterns and site planning that maintain and enhance natural systems, forms, and open spaces (EN-2.0, Comprehensive Plan). Implicit in this objective is the need to define eligibility requirements for use of the mitigation banking sites and to provide a 1:1 acreage replacement on the mitigation banking sites for the 5.33 acres of impact to Category 3 wetlands, pursuant to the agreement between the City of Renton and Glacier Park. • Balance community desires for economic development with the responsibility to retain the City's wetlands base and protect environmental resources. • Protect and enhance water quality of surface water resources (EN-4.0, Comprehensive Plan). • Provide for, and work toward, a regional approach to storm water management programs (EN-10.0, Comprehensive Plan). • Protect and enhance the City's rivers, major and minor creeks and intermittent stream courses (EN-5.0, Comprehensive Plan). Parametriz, Inc. 7 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin Table 4. Anticipated changes in land use in acres (R.W Beck and Associates 1993). Land Use Springbrook Creek Panther Creek Commercial +712.9 +8.2 Multi-family residential -14.0 +96.0 High-density residential +229.4 +347.7 Medium-density residential +144.4 -62.4 Low-density residential -216.3 -91.20 Upland forest -56.3 -160.1 Upland cleared -183.1 -123.3 Lowland undeveloped -626.9 -12.3 Lake 0 -8.1 + indicates increase in land use for the particular zoning *A Y'Ct k - indicates decrease in land use for the particular zoning « 4A-L Table dicates that the anticipated changes in land use in the Springbrook Creek Drainage Basin will be toward more commercial and high- and medium-density residential housing. Commercial development currently predominates in the lowland areas in the western portion of the basin (i.e., Springbrook Creek Drainage Basin) and in the Renton commercial district. A large portion (approximately 1,510 acres) of the Springbrook Creek Drainage Basin is currently undeveloped; however, most of this area is expected to be converted to commercial and high- density residential development. Future development in the Springbrook Creek Drainage Basin convert the existing undeveloped forest land and low-density residential areas to j predominately commercial and high-density residential. The City of Renton estimates that commercial portions of the Springbrook Creek Drainage Basin will be completely developed within the next 5 to 7 years. Assuming that development occurs uniformly during this period, approximately 250 acres of land will be developed each year in the Springbrook Creek Drainage Basin (R.W. Beck and Associates 1993). Full build-out of the Panther Creek Drainage Basin is expected to occur at a lower rate estimated to be between 15 and 20 years. Thus, the amount of land developed each year in the Panther Creek Drainage Basin would be approximately 45 acres. 6.2.3 Water Qualily and Sediment Erosion Sediment loading in the Black River Drainage Basin can deteriorate the water quality and affect aquatic organisms residing in the major streams and tributaries. The major sources of sediment loading in the basin are upland erosion in the watershed and in-stream channel erosion. Upland Parametrix, Inc. 41 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Pumping storm water from the Kent lagoon into the Green River No formal decisions have been made about the flood control alternatives presented in the most recent plans prepared by R.W. Beck and Associates (1991;1993). 6.2.5 Results of Review of Baseline Information and Field Assessment The results of the field assessment of the two mitigation banking sites indicate that both sites contain relatively low-value seasonally perched wetlands that are generally composed of cottonwood,Populus bal�gmifgra;red alder,Alnus rubra; salmonberry,Rubus spectabilis;willow, Salix spp.;..and—r�canarygrass, Phalaris arundinaceae. The wildlife habitat value of the ...mitigation banking sites is limited by development adjacent to and near the properties; although VCGS -? the wildlife habitat value of the large wetland and its associated buffers on Mitigation Banking Site 1 appears to be greater than Mitigation Banking Site 2. Both sites support deciduous trees that are well developed but not fully mature. Consequently, opportunities for cavity-feeding and nesting birds, for example, are limited. The relatively young age of the forested portions of both sites and the relatively low species diversity within the plant communities limit the value of these sites for wildlife. In addition, there are few, if any, permanently wet areas on either site. The existing wetlands are seasonal in character and possess relatively low functional values for flood water abatement and storage, and water purification. The wetlands are also poorly developed and somewhat artificial (i.e., developed on pans in isolated depressions on top of fill), and occur at elevations 5 to 9 feet higher than neighboring water bodies (e.g., Springbrook Creek) Both sites have large areas in which reed canarygrass and introduced blackberry species (Rubus discolor procera, R. lacianatus) have become established. Mitigation Banking Site 1 also has areas in which Scot's broom (Cytisus scoparius) grows. These plant species will continue to expand their ranges unless shaded by taller vegetation, removed, or otherwise controlled manually or chemically. Mitigation Banking Site 2 does not show evidence of human intrusion, but Mitigation Banking Site 1 is frequently used as a sport off-road vehicle area, an activity that has resulted in significant disturbance to the landscape despite efforts by the City to restrict entry for this purpose. A significant amount of fill has been placed on both sites, and the depth of fill appears to be as great as 10 ft in some places. This material generally has low organic content and relatively permeable sandy soil and, although soils in the wetland areas show signs of mottles, the soils may not have been hydric when deposited. Using a backhoe, three soil test locations were dug on Mitigation Banking Site 1 and five were dug on Mitigation Banking Site 2. The soil test locations are shown in Figures 8 and 9, and the results are presented in Figures 10 and 11. Photographs of the soil test locations are provided in Appendix B. Parametrix, Inc. 44 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin ' � ,� ;� ��: d' � � and open space for passive uses within and between the neighboring wetland systems and the mitigation banking site. Flood Storage and Attenuation Mitigation Banking Site 1 provides an opportunity to increase the acreage capacity of flood storage. This site may provide storage opportunities for localized runoff from adjacent and upstream developments, as well as backwater storage from neighboring wetlands. One alternative of a flood and water quality plan being evaluated by the City would create a high-flow bypass system. This alternative would involve realigning a portion of Springbrook Creek so that flows from SW 43rd Street would flow north along the west side of Mitigation Banking Site 1, then flow east toward Springbrook Creek. Minimum flows needed to support fisheries resources would still flow through the existing Springbrook Creek channel between SW 43rd Street and SW 27th Street. Some flood storage and flow attenuation could be provided under this scenario on Mitigation Banking Site 1. If realigning a portion of Springbrook Creek becomes a preferred alternative, a design feature could be incorporated that would route the water through Mitigation Banking Site 1 before entering back into Springbrook Creek. This action would positively impact Mitigation Banking Site 1 by providing greater hydrologic support for the entire wetland system, as well as providing the hydrology necessary to support hydrophytic vegetation reestablished in the upland fill areas of the mitigation banking site (i.e., the restored wetlands). Water Quality Improvements The restored wetlands can help improve local water quality conditions by acting as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways that enter into the drainage basin in Renton. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live, work and visit in Renton. While the wetlands to be established on Mitigation Banking Site 1 have multiple values, one o the primary uses could be to improve the quality of downstream aquatic environments. Wildlife Habitat Because of its size,proximity to higher-value wetlands,and relatively greater isolation from urban development, Mitigation Banking Site 1 provides an excellent opportunity for greatly enhancing both aquatic and terrestrial wildlife habitat. By restoring a variety of wetland types, and by buffering these areas from the impacts of nearby development, a diversity of habitats will be established; that diversity will benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding upon existing natural systems and restoring habitats in areas that have been damaged by human activities ensures better survival of wildlife and provides wildlife viewing Parametrix, Inc. 58 City of Renton - DRAFT 55-1779-07 November 11, 1993 drfimag.pin Wildlife Habitat and Corridor Mitigation Banking Site 2 is next to Springbrook Creek, a ditched and diked channel. The mitigation banking site's proximity to Springbrook Creek offers an opportunity to provide aquatic and terrestrial wildlife linkages to other wetlands, water bodies, and open-space areas, as well as downstream benefits to fish and wildlife. �( Another identified opportunity is to have some wet meadow areas that become relatively dry in 0 late spring and summer for small mammal shelter and foraging. These smaller mammals in turn act as a food source for predatory birds, such as red-tailed hawks, and larger mammals. 1 Providing this type of wetland habitat, along with other wetland habitats (e.g., open water aquatic bed), increases the overall diversity and features inherent in a higher quality wetland system. Finally, the Renton community can be enhanced by restoring a variety of wetland types, linking them to other City-owned, high-quality wetlands, and managing the City-owned wetlands as a connected system. Public Access and Education ................................................................. The City of Renton recreation plans ( ezi ? `> `:rrat ) show trails along Mitigation P................... ................................................................. Banking Site 2. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling, and photography. Education could focus on wildlife, wetlands, salmonid b' to y, urban stormwater quality, etc., and could be offered by interpretive signage and printed materials. Planned trails and wetland and wildlife observation points could provide numerous opportunities for public enjoyment of Renton environments. The wetland environment in Renton could become a favorite place to recreate and learn, particularly if used by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington and South Seattle Community College, these wetlands could be the subject of further study by interested wetland research scientists over the coming decades. 6.3.4 Constraints Constraints associated with restoring both mitigation banking sites are presented below. Where appropriate, differences in constraints for each site are identified. 6.3.4.1 Enhancement Credits The City of Renton's Wetland Management Ordinance does not recognize enhancement as an acceptable form of compensatory mitigation. There are approximately 10 to 15 acres of existing wetlands that could be enhanced and used for mitigation banking if the ordinance was modified in the future. (See Chapter 3, Policy Issue 6.) Parametrix, Inc. 60 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin 6.3.4.2 Hydrology and Groundwater Perhaps the most challenging current constraint is the lack of seasonal depth-to-groundwater data (assumes that groundwater will be the primary source of wetland hydrology or will augment other sources of hydrology such as precipitation and surface water). There is little available on-site water to support restored wetlands. Wetlands on both sites appear to have developed as a result of surface water accumulation due to direct precipitation in slight depressional areas where, over time, finer sediments have accumulated and reduced soil permeability. Hydrologic support for wetlands on Mitigation Banking Sites 1 and 2 appears to be from local precipitation. Thus, the most significant constraint associated with establishing_a hydrology on Mitigation Banking Site ais determining the sources of hydrology and how to manipulate the s,4urces to meet the hydrologic needs of restored wetlands. hh f TT ie available information on existing hydrology for Mitigation Banking Site I is not adequate !to develop specific site designs that could be used to prepare a bid package for restoring the tctuations lands to wetlands. No groundwater monitoring has been done on the site to establish seasonal which could aid in the design of created wetlands (assuming that groundwater is one potential source of hydrology for Mitigation Banking Site 1). Ideally, the level of groundwater should be measured for at least 1 year. Groundwater wells constructed of PVC pipe could be installed and monitored over the late fall, winter and spring. This additional information would allow the conceptual site design to be modified to reflect seasonal fluctuations in groundwater hydrology. An alternative and/or additional source of hydrology is the ditch that runs south to north along the western property boundary. Information on the quantity and quality of the water in this ditch is necessary before a detailed site plan can be produced and appropriate structures can be engineered. Recommendations for collecting hydrology data associated with the ditch on the western and northern boundaries of Mitigation Banking Site 1, groundwater data and other data needed to complete a detailed site design for Mitigation Banking Site 1 were provided to the City in a November 4, 1993 letter (Appendix Q. The amount and quality of hydrology information applicable to Mitigation Banking Site 2 is better than for Mitigation Banking Site 1. Base flows for Springbrook Creek have been modelled and measured (about 8 cfs). Information is also available on mean daily precipitation and water levels in Springbrook Creek. One alternative for bringing water into Mitigation Banking Site 2 involves pumping water directly from Springbrook Creek. The pumped water would provide the primary source of hydrology for the restored wetlands and would augment the hydrology in the existing wetlands. Pumping of water requires an energy source and installation of appropriate structures; costs associated with this alternative are being evaluated. A second alternative involves installing a well on the site west of the dike, and pumping groundwater from the well. The advantage of a groundwater well over pumping water directly from Springbrook Creek are that the quality of water is more reliable and the amount of water needed can be more readily controlled. Although groundwater was observed at an elevation of about 7 feet during the site visit in August, 1993, the depth of the well needed to capture groundwater still needs to be Parametrix, Inc. 61 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin determined. Monitoring groundwater levels in late fall, winter and spring would provide more information that can be used to modify the site plans being developed for the site and to determine, if necessary, the depth of the well needed. The disadvantages to using pump (either from Springbrook Creek or a groundwater well is that pumps require an energy source and maintenance, and are entirely artificial. A�third alternativ is to instal�avi fed ydraulic system in S ri rook Creek and through the dike sQ~ at wa flow eel into Mitigation S`ankin ite 2. This alternative will require relatively extensive excavation of the existing uplands to establish elevations that would match the surface elevations in Springbrook Creek during low flow periods and an engineering design that will prevent fish impingement and entrapment. In addition, excavation of the existing uplands to elevations lower than the existing wetlands may result in dewatering of the existing wetlands. Thus, portions of the existing i' wetlands may also need to be excavated and/or altered to ensure that there will still be a IVA hydrologic source for the existing wetlands, or those portions that are not altered. The site plans �rbeing developed for this site include an alternative that would result in altering existing wetlands, and an alternative that would not alter the existing wetlands. 6.3.4.3 Issues with King County Drainage District No. 1 The King County Drainage District may place restrictions on work associated with altering dikes. For example, installing a conduit through the dike to allow high flows from Springbrook Creek into Mitigation Banking Site 2 could result in additional flood storage capacity in the Valley. The Drainage District may have concerns about the effects on the structural integrity of the dike from installation of the conduit. Thus, the possibility of altering a portion of the dike will need to be discussed with the Drainage District. 6.3.4.4 Balanced Cut and Fill Because of the depth to groundwater observed on both sites in August 1993, and the fact that filling of both sites has placed ground elevations well above original floodplain elevations, the costs to excavate and remove soils would be high. In addition, these conditions would make it costly to establish a direct hydrologic connection between restored wetlands on Mitigation Banking Site 2 and Springbrook Creek. Thus, a balanced cut-and-fill scenario is unlikely given the depth to which excavation must occur if created wetlands are to use groundwater hydrology. If groundwater hydrology is to be used, export of significant amounts of material is likely. Although the costs for excavation would be relatively high, once hydrology is obtained wetland creation success probability increases with correspondingly lower landscape costs (i.e., plant material costs). Alternatively, if groundwater pumped via a well is used to augment hydrology for the restored wetlands on Mitigation Banking Site 2, a more balanced cut-and-fill scenario is likely, and export of soils will be less. Parametrix, Inc. 62 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 6.3.4.5 Urban Development Urban development is in close proximity to both sites. Lots zoned for industrial and 69mmercial Wi uses are directly north of Mitigation Banking Site 2. A major thoroughfare, Oaksdale Avenue," 1 is directly west of the site. Mitigation Banking Site 1 is relatively more isolated from urban lY I development, and will have only a portion of a Oaksdale Avenue along one of its boundaries once construction of Metro's gravity sewer system is complete. evertheless, this site has adjacent o ercial)development along its southern boundary, and further development in this C� area is likely to occur, Existing and future urban development are not significant constraints; they are a reality that needs to be considered when deciding what types of wildlife functions can realistically be expected. 6.3.4.6 Existing Potential Seed Bank The current soil seed bank on both sites may not contain some of the important plant species (e.g., rushes, sedges, bulrushes, bur-reed, cattail, water parsley, water lily) which might be used in the mitigation banking wetlands. Existing plant communities express what is likely held in the seed bank (i.e., black cottonwood, red alder, salmonberry, reed canarygrass, and Himalayan blackberry). However, it is reasonable to suggest that the historic seed bank (prior to filling) contains some of the important plant species that would add structural and species diversity to the mitigation bank. For example, a review of some historic aerial photographs taken of the tributary to Springbrook Creek before it was fil14 dicates that some seeds from plant species that provide habitat structure and diversity. �A 6.3.4.7 Soils Little wetland soil (e.g., peats or muck) is available on either site to use in construction of new wetlands. However, if the clay found within soil test location 2 on Mitigation Banking Site 2 is abundant over the site, it may be suitable for lining some restored wetlands. However, an appropriate planting medium, such as topsoil, may need to be imported to the sites to allow the roots of plants to become established. 6.4 ACREAGE AND TYPE OF MITIGATION FEASIBLE FOR THE MITIGATION BANKING SITES 6.4.1 Acreage of Mitigation Feasible on the Mitigation Banking Sites Combined, both mitigation banking sites can provide a total 19.35 acres of restored wetlands. Specifically, Mitigation Banking Site 1 consists of 30.97 acres of land. Of this total, 18.78 acres are considered to be wetland, leaving a total of 12.19 acres of upland available for establishing wetlands and buffers. Mitigation Banking Site 2 consists of a total of 13.93 acres of land. Of Parametrix, Inc. 63 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin �c loot 6.6 FEASIBILITY OF MITIGATION BANKING PROGRAM The feasibility of the mitigation banking concept is relatively uncomplicated. After areas are acquired and wetlands restored, created, and/or enhanced, the acreage and/or functional value of the created, restored, and/or enhanced wetlands is measured and a total number of mitigation credits are established for the bank (Ford 1991). As wetland development in the Black River Drainage Basin is permitted by the City, existing acreage and functions of wetlands that would be lost are measured by the same method used to assess acreage and function of the banked wetland mitigation, and debits are made to the bank, reducing its credit balance. The terms by which credits are traded for units of permitted wetland loss—the trading ratio—are typically set by the lead regulatory agency to achieve no net loss of wetlands or wetland function. Eventually, all of the credits are withdrawn from the bank to compensate for wetland losses, and a new bank can be established by rehabilitating or creating new_wetland-habitat Sho�'88). ale df{ f... .c V-6,y 'e (Wetland mitigation banking was developed as an administrative strategy toQdeal with compensation for unavoidable project-related resource losses. This form of mitigation differs from concurrent compensatory mitigation in that theLoff-sit mitigation is not necessarily exclusive to one specific project and the mitigation occurs in advance of project impacts (Figure 12). Mitigation banking is intended to involve only those habitat protection, creation, or improvement measures taken expressly to compensate for habitat losses associated with future development actions (Short 1988). Mitigation banking requires that a plan be conceived and implemented that identifies the location of wetland resources, characterizes wetland functions, develops an overall scheme for wetland resource management prior to any proposal for wetland alteration, and identifies the implementation process for using the mitigation banking program. Short (1988) describes mitigation banking as follows: ...mitigation banking is similar to maintaining a bank account. A developer undertakes measures to create, restore, or preserve fish and wildlife habitat in advance of an anticipated need for mitigation for future project construction impacts. The benefits attributable to these measures are quantified, and the developer receives mitigation credits from the appropriate regulatory and/or planning agencies. These credits are placed in a mitigation bank account from which withdrawals can be made. When the developer proposes a project involving unavoidable losses of fish and wildlife resources, the losses (debits) are quantified using the same method that was used to determine credits, and a withdrawal equal to that amount is deducted (credited) from the bank. This can be repeated as long as mitigation credits remain available in the bank. An alternative off-site mitigation program to mitigation banking is concurrent compensatory mitigation. Concurrent off-site mitigation allows a project proponent to develop a project site and mitigate concurrently for impacts to wetlands at a selected site within the same drainage basin, or other defined area. Parametrix, Inc. 68 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin Models for Compensation of Wetland Impacts TIME PROJECT TIME IMPACT V w cwi.W5z—b V6Y t q Msr 45310,4 MA<pg hoAJsE Functionsand ! Project Evaluation Values >:: Wetland gation • Extent of Impact Creation Priorities "` Assessment • Functions and Monitoring Values Assessment • Mitigation Options - Avoidance/ Compensation - On-site/Off-site Functions • Determine gation Wetland and Compensation Priorities Creation Values Requirements Assessment Monitoring i i CONCURRENT COMPENSATION MITIGATION BANKING ......................... .................... :::...: ?tip Figure 12. Types of Mitigation Programs The City's Wetland Management Ordinance allows project proponents to consider off-site mitigation for wetlands [Section 4-32-6 (e and f)] in addition to on-site mitigation. The City also allows project proponents to combine mitigation requirements from different projects or to pool mitigation requirements of several developers. However, several developers, or one developer, that own many parcels containing wetlands would need to time their projects so that impacts and compensation for those impacts occur concurrently. The primary differences between a concurrent off-site mitigation program and a mitigation banking program are that: (1) concurrent wetland mitigation occurs strictly within the context of a regulatory permit process, (2) mitigation occurs outside of the context of a plan that identifies regional and local goals for allowing resource protection and economic development, (3) the responsibility for mitigation(site acquisition through implementation,monitoring, etc.) lies solely with the developer, and(4) mitigation projects would be pi -mealed on one larger site and there is little control over how individual mitigation projects are i plemented, onitored, and managed. rt On a technical basis, allowing a developer to use a portion of one of the two mitigation sites for concurrent compensatory mitigation requires the developer to leave the remaining upland undisturbed for another developer to use at a later date. For example, assume that the City uses Mitigation Banking Site 2 to fulfill its obligation to provide 5.33 acres of compensatory wetland mitigation for impacts that occur on individual 1-acre parcels owned and developed by the Glacier Park Company. Implementing the mitigation for only 5.33 acres will leave a total of 1.83 acres of additional upland that could be restored to wetland. How will the City create/restore only 5.33 acres and leave the remaining upland acreage unaltered for another developer to potentially use? Assuming that the remaining upland acreage will be left undisturbed for a future off-site mitigation project,the activities undertaken to complete the first off-site mitigation project may affect the success and viability of the second mitigation project. A wetland mitigation banking program developed and implemented by the City, with assistance from the private development community, is recommended because the potential advantages outweigh the potential disadvantages, and the potential disadvantages are not insurmountable. The advantages and disadvantages associated with the feasibility of establishing a mitigation banking program are provided below along with recommendations for addressing the potential disadvantages to mitigation banking. 6.6.1 Advantages of Mitigation Banking_ • Mitigation banks designed and sponsored by resource agencies with experience and motivation to complete the mitigation project usually have a greater potential for successfully meeting program objectives than do mitigation projects designed and Parametrix, Inc. 70 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag.pin • With mitigation banking, credits are based on wetland values that are present on the site rather than potential wetland values that are anticipated for off-site compensatory mitigation projects. • Monitoring, evaluation of mitigation compliance and success, and implementing contingencies are easier and more efficient with fewer larger sites (Short 1988). 6.6.2 Disadvantaues of Mitigation Banking Program • The general public may perceive that the bank is available to compensate for impacts that would otherwise be avoidable. • The development community may perceive the bank as a mechanism to ensure blanket approval of future permit applications. C/There is a large initial investment of time and expense involved with establishing a mitigation banking program. The disadvantages to a mitigation banking program in the City of Renton are not insurmountable. The City of Renton Wetland Management Ordinance requires that project proponents take steps to avoid and minimize impacts to wetland resources before considering any form of compensatory mitigation(i.e., on-site,off-site,consolidated off-site mitigation,or mitigation banking). Provided that the City continues to use this sequencing system, or a surrogate, and evaluates each project permit application according to pertinent laws, policies, and guidelines, the bank is not likely to be used to compensate for project impacts that may be avoidable. One intent of the mitigation banking program is to provide an economical option to other forms of mitigation for projects proponents whose projects result in unavoidable losses to wetland resources. The mitigation plan will require that public and private project proponents meets certain eligibility criteria, and standards associated with the criteria, before using the mitigation banking program. Using eligibility criteria to determine the appropriateness of using the mitigation banking program will help to eliminate perceptions, if any, that the mitigation banking program will ensure blanket approval of future permit applications. The City may have to finance and take the lead on the initial restoration of the total available upland acreage to wetlands on one of the two mitigation banking sites (i.e., Mitigation Banking Site 2). The City could then bank the remaining wetland acreage (1.83 acres after the 5.33 acres are completed) to encourage private participation. The City needs to provide 5.33 acres of mitigation pursuant to its agreement with the Glacier Park Company. If the City used Mitigation Banking Site 2 to fulfill this obligation, it would appear to be more cost-effective to restore the entire upland portion of Mitigation Banking Site 2 versus just the 5.33 acres because the total acreage available on this site is 7.16 acres. plot -dj Parametrix, Inc. S i y N S 72 City of Renton - DRAFT 55-1779-07 t^ November 11, 1993 drftmtig.pin �D C' SColr wow'eagi'13 C- )ft*\4J-r.T CHAPTER 3. POLICY ISSUES During discussions between the City and the project team, several policy issues were identified that require discussion and resolution by the City. The issues are identified below, followed by a brief discussion of the issue, options to resolve the issue, advantages and disadvantages to the options, and a recommendation. 3.1 POLICY ISSUE 1: Should the City be Eligible to Use the Mitigation Banking Sites for Public Projects? 3.1.1 Issue �POCGP joO Under the current City of Renton Wetland Ordinance, a wide range of city-sponsored activities can occur in wetlands without obtaining a special permit. These activities are outlined in the City of Renton Wetland Management Ordinance (City of Renton 1992), Section 4-32-4 and include: • Activities affecting a single, hydrologically isolated Category 1 or 2 wetland of less than 2,200 sq ft within a property boundary (City of Renton 1992; Code Section 4-32-4.C.1). • Activities affecting hydrologically isolated Category 3 wetlands of less than 5,000 sq ft within a property boundary (City of Renton 1992; Code Section 4-32-4.C.2). • Normal and routine maintenance and repair of existing facilities where no alteration of the wetland or additional fill materials will be placed (City of Renton 1992; Code Section 4-32-4.A.4). The area must be restored to original conditions. • Normal and routine maintenance and repair with minimum placement of fill to bring facility up to established safety standards(City of Renton 1992; Code Section 4-32-4.A.5). Impact must be minimized and area restored. • Site investigation work necessary for land use application submittals such as surveys, soil logs, percolation tests, and other related activities (City of Renton 1992; Code Section 4- 32-4.A.8). • New surface water discharges to Category 1, 2, and 3 wetlands where discharge meets Chapter 22 of the City's Storm and Surface Water Drainage Ordinance. These activities will not result in significant changes in water temperature or chemical characteristics, and any changes in hydrology that would result in greater wetland function and value (City of Renton 1992; Code Section 4-32-4.A.9). Parametriz, Inc. 10 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmog.pin • Regional storm water management facilities designed consistent with the Washington State Department of Ecology's Wetlands and Storm Water Management Guidelines (City of Renton 1992; Code Section 4-32-4.A.12). • Enlargement of facilities beyond existing needs provided footprint does not increase more than 10 percent within the wetland or its buffer(City of Renton 1992; Code Section 4-32- 4.C.6). • Emergency activities (City of Renton 1992; Code Section 4-32-4.D). As outlined above, the Wetlands Management Ordinance (City of Renton 1992) allows for a wide range of city-sponsored public activities without needing to compensate for the temporary or minor disturbance to wetlands. However,there are other public projects(e.g.,transportation,road improvements, public works) that the City may consider in the near and long term whose impacts to wetlands may require compensatory mitigation as per the City's Wetland Management Ordinance and/or state and federal wetland regulations. These impacts could be compensated for through the use of the proposed mitigation banking program. 3.1.2 Options 3.1.2.1 Option 1: Allow public project impacts to be mitigated for at the mitigation banking sites (assumes that the public project meets the eligibility requirements for using the mitigation banking program) Advantages • The City would not have to necessarily provide on-site mitigation. • The City would not have to necessarily acquire additional land to implement an off-site mitigation design. • State and Federal regulatory agency acceptance of the credibility of the mitigation banking program could increase with City participation. • Allowing public projects to be eligible provides an opportunity for a partnership between public and private developers. Disadvantages • The amount of available "banked" wetland mitigation on the sites may diminish relatively fast if numerous public projects that affect higher quality wetlands (i.e., Category 1 and Parametrix, Inc. 11 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 2 wetlands) are implemented and are mitigated for at the mitigation banking sites (i.e., less banked wetland credit available for use by the private sector). • There is the potential that the general public may perceive the City as giving preferential treatment to meeting the eligibility requirements for public projects. 3.1.2.2 Option 2: Do not allow public project impacts to be mitigated for at the mitigation banking sites. Advantages • Leaves more "banked" wetland available for private projects. • There may be more public interest in the mitigation banking program if it was designed just for the private sector. Disadvantages • The City would need to acquire land to conduct off-site mitigation for public projects if on-site mitigation could not be achieved. • The City would not be able to take advantage of the mitigation banking program - a program to which they are committing substantial financial resources. • State and federal agencies may not be as supportive of the mitigation banking program if it is designed solely for the private sector. 3.1.3 Recommendation Comments from the general public (October 20, 1993) and the development community (October 21, 1993) were considered when making this recommendation. Considerations included the fact that public projects serve a public need benefiting the entire community, and that implementation of the mitigation banking program may be financed, in part, by the City (e.g., 5.33 acres of mitigation required for allowing fill on Glacier Park properties, Parks and Recreation trail development). We recommend that wetland mitigation for public projects that meet the eligibility requirements for using the mitigation banks be allowed on the mitigation banking sites. However, the City should consider limiting public participation to not exceed 50 percent (7.01 acres) of the total available mitigation banking acreage (14.02 after the 5.33 acres of mitigation for Glacier Park is subtracted from total acreage of 19.35), thereby providing at least,50 percent.,(7.0.1,) of wetland mitigation banking available for private develo ments [PUT IN FOOTNOTE HERE: �Assumes that enhancement is not allowel"fee ection 3.6, Policy Issue 6). Parametrix, Inc. 12 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3.2 POLICY ISSUE 2: Should the Mitigation Banking Sites be Used for Impacts to Category 1 and 2 Wetlands, or Only for Projects Impacting Category 3 Wetlands? 3.2.1 Issue In early conversations about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting Category 3 wetlands should be eligible to use the bank (Appendix A, Wetland Management Ordinance). The general reasoning was that this category represented the majority of wetlands within the Valley, and impacts would tend to occur on the smaller and lower value wetlands. A review of the Wetlands Management Ordinance and the current city wetland inventory indicates that some Category 1 and 2 wetlands could also be potentially eligible to use the bank. Deciding on whether to consider impacts to Category 1 and 2 wetlands eligible for use of the mitigation bank is dependent, in part, on (1) the number and acreage of Category 1, 2, and 3 wetlands within the Valley, and (2) interpretation of the City's Wetland Management Ordinance. Based on the available wetland inventory data there are 17 Category 3 wetlands ranging in size from less then 1 acre to about 20 acres, 15 Category 2 wetlands ranging in size from less than 1 acre to about 23 acres, and three Category 1 wetlands ranging in size from 20 to 65 acres. The City of Renton owns all of the Category 1 wetlands (Table 1, see Figure 1). r�,g- pu`,-r- /ow ti Poklt�o fc w The City's Wetland Management Ordinance is somewhat ambiguous with respect to whether Category 1 and 2 wetlands can be impacted. As currently interpreted, the ordinance does not preclude development activities in Category 1 and 2 wetlands; but it does not actually state that these wetlands can be altered, or state what activities are regulated in these higher quality wetlands. 3.2.2 Options: 3.2.2.1 Option 1: Allow the mitigation banking sites to be used for impacts only to Category 3 wetlands. Advantages • Potential impacts to Category 1 and 2 wetlands would be minimized if project proponents could not use the mitigation banking sites and had to do on-site and/or off-site mitigation (i.e., disincentive to impact Category 1 and 2 wetlands). • Ensures that only lower quality wetlands are being impacted, mitigated for, and replaced with greater functional value. Parametrix, Inc. 13 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Table 1. Inventoried wetlands within the Black River Drainage Basin. r Wetland Size Wetland Code Type (acres) Category 1 2 W-4 3 PFO,PSS,PRM 65 W-5 3 PFO 20 W-12 3 PSS,PEM 41 Total 3 Category 2 2 W-25 PFO I or less W-40 PEM,PSS l or less W-43 PEM t or less W-44 PEM,PSS 1 -2 W-3 POW,PFO,PEM 5-6 W-38 PFO,PSS,PEM 5-6 W7N PEM,PSS 11 - 12 W8N PSS,PEM 11 -12 W13C POW,PEM,PSS 11 - 12 W-10 PFO,POW 12- 13 W-22 PEM,PSS,PFO 18- 19 W45 PFO,PSS,PEM 18-19 W5C PFO,PSS 23 Wit PEM,PSS 28 W37 POW,PEM,PSS 62 Total 15 Category 3 2 W-31 PFO,PEM 1 or less W-34 PEM 1 or less W-35 PEM 1 or less W-9 PFO 1-2 W-16 PEM,PSS 1 -2 W-36 PEM 1 -2 W-6 PFO,PSS 2-3 W-7S PSS,PEM 2-3 W-15 PFO,PSS 2-3 W-41 PSS,PEM 2-3 W-14 PSS,PEM 3-4 W-33 PEM,PSS 3-4 W-8S PSS,PEM 4-5 W-13a PFO,PEM,PSS 4-5 W-21 PEM,PSS 4-5 W-32 PFO,PSS 6-7 W-13b PEM 20 Total 17 Uncategorized W 19 PEM 2 @ 1.7 W 1 PFO 30 Total 2 Notes: A portion of W-22 is Wetland Mitigation Site I A portion of W-32 is Wetland Mitigation Site 2 1 From R.W.Beck 1993,Black River Basin Draft Water Quality Management Plan,Volume 3 and Jones and Stokes 1991,Critical Areas Inventory,City of Renton Wetlands and Stream Corridors 2 Category is based on City of Renton wetland ordinance 3 Owned by the City of Renton PEM =Palustrine emergent PSS =Palustrine scrub shrub POW =Palustrine open water PFO =Palustrine forested • Focusing the mitigation banking program on Category 3 wetlands may result in greater opportunities to retain and expand the City's economic base. • Administrative management of the mitigation banking program would be relatively simple. Disadvantage • Projects that may impact Category 1 (public only) and 2 (public and private) wetlands would not be eligible to use the wetland mitigation bank and would need to consider on- site and/or off-site mitigation alternatives. 3.2.2.2 Option 2: Allow the sites to be used for impacts to Category 1 and 2, as well as Category 3 wetlands. Advantages • Provides greater opportunity for the development community to use the mitigation banking program and does not necessarily preclude public and private development in Category 1 and 2 wetlands. • Provides opportunity for City to use the mitigation banking sites for impacts to Category 1 wetlands. Disadvantages • Potential to use up the acreage created for the bank relatively fast because of greater replacement-to-loss ratio prescribed by the City's Wetland Ordinance (City of Renton 1992) (i.e., potentially fewer users). • Higher value wetlands have higher buffer requirements, resulting in a net reduction in wetland mitigation area available for banking. 3.2.3 Recommendation Based on the available information on inventoried wetlands under the jurisdiction of the City of Renton, the majority of wetlands that may be subject to future development activities appear to be primarily a combination of both Category 2 and 3 wetlands, with Category 3 wetlands appearing to be more abundant than Category 2 wetlands. The majority of the Category 3 wetlands occur in the portion of the Valley where economic development is desirable. Therefore, it is reasonable to expect the majority of impacts to occur to Category 3 wetlands. r-A,PlNtiry /A,A,IJU'? Parametrix, Inc. 15 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Doss,/SG�t To 5f �'I 7"'rS )F No7 AO- ,,5 wJ pe76.wt1a(_ AS r-oti aThr4 AM,s F"62 c.Ar Z . Cvat►u--Td OFF-31,rf Neither the general public nor the development community objected to allowing impacts to /' T1'5 Category 2 wetlands being potentially compensated for at the mitigation banking sites. However, the general public did not want impacts to Category 1 wetlands to occur and be mitigated for on the mitigation banking sites. The City is currently the sole owner of Category 1 wetlands within the Black River Drainage Basin [with the exception of a portion (about 40 percent) of the Panther Creek Wetland]. Future public projects (e.g., extension of Oaksdale Avenue) may affect a NFL portion of the adjacent Category 1 City of Renton Wetland (see Figure 1). ""Any impacts willA� 0,j need to be mitigated for according to the City of Renton's Wetland Management Ordinance (City "P of Renton 1992) and/or according to the Corps (and advisory state and federal resource agencies) permit conditions. The City should, at a minimum, have the opportunity to mitigate for those wetland impacts on the mitigation banking sites. Because it is unlikely that significant portions of City-owned Category 1 wetlands will be impacted, we recommend that compensating for impacts to Category 1 wetlands be allowed at the mitigation banking sites. We also recommend that the City consider allowing compensation for impacts to Category 2 as well as Category 3 wetlands to occur at the mitigation banking sites. Do y ov pAt',,,,,,.,,,,wo A*,y R er r c S E TfNSinv" lNkxMM IN R,ATi,) ' The City needs to remember that any wetland under the jurisdiction of the Corps (and associated agencies such as the U.S. Environmental Protection Agency [EPA] and the Washington State Department of Ecology [Ecology]) are subject to federal and state regulatory requirements. The Corps and Ecology may not determine that compensation for impacts to a given wetland under their jurisdiction is appropriate at the mitigation banking sites. Finally, the section of the City's Wetland Management Ordinance on allowed and regulated activities (Section 4-32-4) is subject to broad interpretation for whether Category 1 and 2 wetlands can be impacted. Therefore, we recommend that the City request administrative clarification to determine whether the ordinance intended to allow impacts to Category 1 and 2 wetlands. 3.3 POLICY ISSUE 3: Should the Mitigation Banking Sites be Used for Impacts to Wetlands That are Less Than 1 Acre, or for Projects Impacting Wetlands 1 Acre or Greater in Size? 3.3.1 Issue In early conversations with the City of Renton about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting wetlands of less than 1 acre, and considered to be above the headwaters, should be eligible to use the bank. The general reasoning for this was that any permitting decisions and requirements for mitigation would largely be a City Parametrix, Inc. 16 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag.pin responsibility and impacts to these wetlands would not necessarily require a permit from the Corps' and/or Ecology'. However, there are wetlands within the Valley that are larger than 1 acre and a developer (public or private) may determine that unavoidable impacts to a proposed project are going to impact greater than 1 acre of wetland. For impacts to wetlands greater than 1 acre, a permit (either a Nationwide 26 permit for above the headwaters or isolated wetlands or Section 404 individual permit for adjacent wetlands) to fill the wetland is required from the Corps and/or Ecology. 3.3.2 Options: 3.3.2.1 Option 1: Allow the mitigation banking sites to be used for impacts only to wetlands that are less than 1 acre and above the headwaters. Advantages • The City is the primary agency involved in permitting these types of activities and with working with the development community to determine appropriate compensatory mitigation. • Reduces the level of coordination necessary with state and federal resource and regulatory agencies, thus reducing the time invested in the administrative and technical management of the mitigation banking program. Disadvantages • May preclude a project proponent(public or private) from being able to use the mitigation banking site if other state and federal permit requirements could be met for wetlands 1 acre or larger. • If the Corps determines that many of the wetlands in the Valley are adjacent, the wetlands that would be eligible to use the site would shift to the upper drainage basin areas. These 2 We are assuming that some of the wetlands within the Valley that are less than 1 acre are indeed wetlands that are above the headwaters, thereby allowing the City to be the sole agency managing activities in those wetlands and the wetland mitigation banks. Should the Corps determine that the majority of wetlands within the Valley are "adjacent," the usefulness of a City managed wetland mitigation banking program will need to be addressed. ' The Corps and Ecology should be notified when a project is going to impact a wetland that is less than 1 acre and above the headwaters. The Corps will typically issue a jurisdictional letter and/or a Nationwide 26 permit. However, the Corps and Ecology have not typically required mitigation for impacts to wetlands that are less than 1 acre and above the headwaters. 171 .. Parametrix, Inc. 17 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.p1n areas are often considered to be of higher value because they are less disturbed and are often associated with primary and secondary stream tributaries. 3.3.2.2 Option 2: Allow the sites to be used for impacts to wetlands that are less than 1 acre in size and 1 acre or greater in size that are either above the headwaters or adjacent. Advantage • Provides an opportunity for project proponents (private or public) that can meet state and federal regulatory requirements to potentially use the mitigation banking site.' Disadvantages • The wetland mitigation banking credit could potentially be used by one large project, thereby limiting opportunities for others who develop in the Valley. • An investment of time and resources may be needed to coordinate and negotiate an agreement with state and federal resources agencies. • Agencies(i.e., Ecology, EPA)require higher-value wetlands to have larger buffers. These buffer requirements may need to be met on the mitigation banking sites, thereby reducing the total available wetland acreage. • Up-front costs for the mitigation banking program could potentially increase. • State and federal agencies may have a difficult time agreeing that mitigation on the banking sites will be adequate compensatory wetland mitigation. 3.3.3 Recommendation The project team recommends that wetlands that are less than 1 acre and above the headwaters be eligible to use one of the two mitigation banking sites (e.g., Mitigation Banking Site 2). As envisioned, impacts to less than 1 acre of either Category 1, 2, or 3 wetlands that are considered ' Impacts to wetlands that are under federal jurisdiction need to be substantiated by meeting the alternatives analysis Section 404 (13)(1) guidelines of the Clean Water Act. The basic presumption of the alternatives analysis is that there is a less environmentally damaging practicable alternative to a project that is not dependent on water, including wetlands. Thus, depending on the type of project, it is unlikely that many project proponents who want to develop wetlands within the Valley could pass the alternatives analysis. If this assumption is true then it is likely that few impacts from projects that are subject to the federal requirements could potentially be offset at the mitigation banking sites. Parametrix, Inc. 18 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin to be above the headwaters would be permitted (including mitigation requirements) primarily by the City of Renton and mitigated for at one of the two mitigation banking sites. However, if a project proponent can meet the state and federal regulatory requirements associated with activities affecting wetlands [e.g., Section 404 (B)(1) alternatives analysis of the Clean Water Act], and the agencies, including the City of Renton agree that mitigation banking is the best compensatory mitigation option, the impacts could be offset at the other of the two mitigation banking sites. Under this scenario, the City of Renton may not necessarily need to meet and negotiate a Memorandum of Agreement with the federal and state resource agencies that also have regulatory oversight of the wetlands. However, the City will need to participate in the evaluation process with the state and federal agencies to determine if the mitigation banking site is the best option to compensate impacts to wetlands 1 acre or greater that are above the headwaters or adjacent. I-a ;�) �,f W/ mop, . fAV Ca l/0�/C PR!�lAt� fFJJk'15 w"t NO'f f"5UE 0"/eOPvY*evr 7AAT 7716( a,3 61 To ensure that sufficient wetland banking credits are available at the two mitigation banking sites, we further recommend that the mitigation banking program give preference to projects that impact less than 1 acre of Category 1, 2, or 3 wetlands that are above the headwaters. Adequacy for using the mitigation banking sites would need to be determined for projects that affect 1 acre or more of wetland. This concept is illustrated below in Table 2. Table 2. Recommended preference for allowing impacts to be compensated for at the mitigation banking sites. Size Priority Wetland Category (acres) Jurisdictional Status 1 Category 3 <1 above the headwaters 2 Category 2 <1 above the headwaters 3 Category 1 <1 above the headwaters 4 Category 3 >_1 above the headwaters or adjacent 5 Category 2 >_1 above the headwaters or adjacent 6 Category 1 >_1 above the headwaters or adjacent Parametrix, Inc. 19 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag.pin 3.4 POLICY ISSUE 4: Should the City be Solely Responsible for Administrative and Technical Management of the Mitigation Banking Program and Mitigation Banking Sites? 3.4.1 Issue The overall management of a mitigation banking program includes an administrative and technical management component. In general, administrative management includes: • Establishing the administrative agent • Credit brokering and credit tracking • Collecting and tracking fees • Financial issues and funding • Permit tracking • Being the bank operator (day-to-day management) In general, technical management of the sites includes: • Determining whether the project is suitable to use the mitigation banking program • Monitoring credit evaluation • Site maintenance • Implementing contingency actions • Oversight of site construction The commitment of individual(s) and time to manage the mitigation banking program requires, at a minimum,that the individual(s) be knowledgeable about permitting(local, state, and federal), wetland delineation, functional monitoring evaluations, financial management, and public relations. Currently, the City of Renton has staff with experience and expertise in evaluating SEPA checklists, permit applications, fiscal and financial (permit fee tracking) management, and public relations. However, it is the project team's understanding that the City requests technical wetland expertise from Ecology regarding SEPA checklists/permit applications that affect wetlands, wetland delineations, and mitigation plans. Parametrix, Inc. 20 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3.4.2 Options 3.4.2.1 Option 1: The City of Renton is the sole administrative and technical manager of the mitigation banking program and mitigation banking sites. Advantages • Typically programs that are administered and managed by one entity are more efficient and coordinated. • Project proponents have a greater sense of predictability associated with how the program works. • There may be reduced costs if the program were managed by the City. • The City would benefit from the technical knowledge it gains on mitigation banking; this could be used when developing other mitigation banking sites within the City. • The City engenders a level of trust and credibility with the users of the mitigation banking program because of the City's administrative and technical knowledge. Disadvantages • It may be difficult for the City to keep abreast of the growing body of knowledge regarding wetland creation, restoration, functional assessment, and monitoring techniques that may be applicable to the mitigation banking program. • The City will need at least one staff person who is knowledgeable about technical issues, administrative and financial management, public relations, and permitting. This person would need to be dedicated 100 percent to the program. 3.4.2.2 Option 2: The City of Renton is the administrative manager of the mitigation banking program and contracts out the technical management components of the program. Advantages • May ultimately be less expensive to contract out for technical management (i.e., monitoring, site maintenance, assistance with evaluating permit/SEPA applications, site visits to assess impacts to wetlands, review of wetland delineation reports, etc). Parametrix, Inc. 21 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Potentially more technical expertise is available from contractors that can benefit the program. • Allows the City to focus on the administrative management functions, oversee the contractor(s), and day-to-day management responsibilities. Disadvantaizes • City has to manage one or more contractors. • City may potentially lose knowledge to be gained because of indirect participation in the technical management components of the program. 3.4.3 Recommendation The City should consider hiring a contractor/consultant for at least the first 2 or 3 years of the program, from site development through site monitoring for two reasons: (1) there may be a perception among the regulated community and general public that the City should not be the developer of the program, manager of the program, and user of the program without involving an objective parry, and (2) the City can benefit from the technical expertise of contractors and consultants that have experience in monitoring, functional assessment, review and verification of wetland delineations and reports, etc. If this recommendation is accepted, the designated staff person from the City that will be the administrative manager of the program should maintain an active role in the technical management components of the program so that the City could eventually be the technical manager of the sites. We also recommend, irrespective of the choice of options that the City does not rely solely on Ecology for technical assistance with projects that Skh- may potentially use the wetland mitigation banking program. We also recommend that the City develop a simple mechanism to notify the Corps when the City is allowing a project proponent to use the mitigation banking site that will allow mitigation for impacts to wetlands less than 1 acre that area considered to be above the headwaters (activities for altering those wetlands are authorized by the Corps Nationwide 26 permit process). The purpose of establishing a mechanism is to provide the Corps with information on what the City is requiring for mitigation associated with filling wetlands. Notifying the Corps of City actions will allow the Corps to have a record in the event that they are contacted about a potential fill violation. The mechanism would include: 1. Identifying one individual in the Corps regulatory division and one individual at the City of Renton to be the point of contact for this program. 2. The City requiring a project proponent to submit a copy of the Corps' letter on the jurisdictional determination of the wetland(for sites without specific project plans), a copy Parametrix, Inc. 22 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.p1n c.JOUL�) �r`o a u. PF�.w, rs HPP(� 05f of the Nationwide Permit, or the Letter of Authorization (for sites with specific project plans), before the City allows the project proponent to use the mitigation banking program (this is one of the proposed eligibility requirements). 3. The City then gang a form letter that references the Nationwide Permit number, the ��sE Letter of Authorization, or the Corps letter and which indicates that the City intends to allow the project proponent to use the mitigation banking site(s) to offset losses to wetland resources. The letter would, at a minimum, include a description of the impact (e.g., location, size) and a summary of total wetland acreage available on the mitigation banking sites, total acreage used by the specific project and the total mitigation banking acreage remaining. The form letter should be sent to the designated contact person at the Corps for their files and for its office of law enforcement. 3.5 POLICY ISSUE 5: Should the City Consider Exempting Category 3 Wetlands From the Sequencing Process(i.e.,Avoidance,Minimization Compensation) Currently Required by the City's Interim Wetlands Ordinance? 3.5.1 Issue Currently the City of Renton's Wetland Management Ordinance requires that impacts to Category 1, 2, and 3 wetlands from development projects first be avoided and then minimized. Once project impacts have been avoided and minimized, any unavoidable impacts are then compensated. This process is typically referred to as sequencing of project impacts. This sequencing process is consistent with state and federal policies and regulations for wetland protection and management. 3.5.2 Options 3.5.2.1 Option 1: The City exempts Category 3 wetlands from sequencing.' Advantages • Eliminates one procedure of the City's Wetland Ordinance with which project proponents need to comply. • Potentially reduces time spent in project design. ' This option assumes that only Category 3 wetlands of less than 1 acre that are above the headwaters would be exempt, because any wetland impact subject to state and federal regulatory requirements would require sequencing. Parametrix, Inc. 23 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Potentially provides added incentive for developers wanting to locate/build industrial, commercial, and residential developments in the Valley. • Provides flexibility to project proponent in site planning and design. Disadvantages • Only Category 3 wetlands under the primary jurisdiction of the City could be exempt (wetlands under state/federal regulations would still be subject to sequencing). • Does not preclude developer from getting a jurisdictional determination from the Corps. • Special features of the site (i.e., provides flood storage) may make exemption disadvantageous to achieving the policy of no net loss of wetlands and wetland functions. 3.5.2.2 Option 2: The City does not exempt Category 3 wetlands. Advantage • All wetlands, whether they are governed by local, state, or federal regulations, are considered equal with respect to sequencing of project impacts. Disadvantage • Potentially may reduce economic incentive for developing lower quality Category 3 wetlands. 3.5.3 Recommendation While exempting certain Category 3 wetlands from the sequencing process would be viewed as advantageous for site developers, we recommend that the City continue to require sequencing of impacts for all wetlands, at least during the first year or two of the mitigation banking program, for three reasons: 1. Some of the development community and general public may perceive inequality in how wetland impacts are evaluated by the City. 2. Some Category 3 wetlands of less than 1 acre (that are above the headwaters) may provide a relatively significant function whose impact may affect achieving the policy of no net loss. Parametrix, Inc. 24 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3. Potentially, the time required by the mitigation banking program manager to track and manage exempted wetlands may increase, and result in increased administrative costs. �.n N FI hrv- We also recommend that the City reevaluate the option of exempting Category 3 wetlandsAless tiu? than 1 acre that are above the headwaters once the program has been implemented and operating (5T ,,,,F�,f for 1 to 2 years. At that time it can be determined whether exempting certain Category 3 wetlands can be done equitably and with minimal paperwork. 3.6 POLICY ISSUE 6: Should the City Consider Modifying the Existing Interim Wetlands Management Ordinance to Recognize Enhancement as an Acceptable Form of Compensatory Mitigation? The City's Wetland Management Ordinance does not currently recognize enhancement as a compensatory mitigation option [City of Renton 1992; Code Section 4-32-6(b)(1)], because at the time the ordinance was developed the City decided that enhancement was difficult to define—and the City lacked the technical expertise necessary to determine if enhancement actually occurred. In general, enhancement is considered to mean those actions that are taken to improve upon or establish new functions within an existing wetland. 3.6.1 Options 3.6.1.1 Option 1: The City modifies the interim Wetland Management Ordinance to recognize enhancement as an acceptable form of compensatory mitigation. Advantages • Provides an additional compensatory option for developers to consider. • Increases the acreage (approximately 10 to 15 acres) available on the mitigation banking sites that could be used as credits in the mitigation banking program. • Establishes consistency with other local, state, and federal wetland mitigation programs (most recognize enhancement as one of several compensatory mitigation options). Disadvantages • The City will need to define enhancement, establish criteria that will evaluate the success of enhancement, and develop technical expertise to determine when a wetland has been enhanced. Parametrix, Inc. 25 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin • The City's ordinance would need to be revised to reflect that mitigation of wetland impacts is based on acreage as well as function. • Anyone proposing enhancement actions on an existing wetland may be subject to local, state, and federal regulations regarding altering wetlands. 3.6.1.2 Option 2: The City does not modify the interim Wetland Management Ordinance to recognize enhancement. Advantages • The City would not necessarily need to modify the existing ordinance, define enhancement, or acquire expertise to determine when enhancement actions have been successful. Disadvantages ND .���<�;�C,. � 4.,, 1. : 1, ;,. f -, 1, - ,. • Minimizes opportunities for on-site mitigation actions that could potentially increase or improve upon wetland functions. • Existing wetlands on the mitigation banking sites could not be altered to increase their functional value. to( je�e�� 3.6.2 Recommendation We recommend that the City consider modifying the existing Wetlands Management Ordinance to include enhancement action as a wetland mitigation option, for the following reasons: 1. Potentially, many developments would consider enhancement options either on-site or at the mitigation banking sites. 2. Actions could be taken on the mitigation banking sites to improve upon some of the existing wetland communities by either the City or private developers. 3. Enhancement provides an opportunity to fulfill some of the objectives and policies of the mitigation banking program. If the City agrees with this recommendation, the mitigation banking program could incorporate trkP F,JR. SF,��fia�J enhancement at a later date - modification of the ordinance would not necessarily need to occur cr before the mitigation banking program is adopted and implemented. Modification could occur Af.q e.<:,Nsrr.Vcr when the City adopts final critical areas ordinances according to schedules determined through the Growth Management Act (Due in 1994). However, modification of the ordinance prior Parametrix, Inc. 26 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin rlrK a� ho rc�,#n h\vsr " �cc,, W t y to or concurrently with the mitigation banking program would provide an opportunity for the City to undertake enhancement actions concurrently with restoration of wetlands on the mitigation banking sites. This would result in a more integrated approach to establishing higher values and functions on the mitigation banking sites, and may result in long-term cost savings (versus independent on-site modifications after the uplands on the mitigation banking sites have been restored to wetlands). Parametrix, Inc. 27 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin �N 5-TMXA CHAPTER 3. POLICY ISSUES During discussions between the City and the project team, several policy issues were identified that require discussion and resolution by the City. The issues are identified below, followed by a brief discussion of the issue, options to resolve the issue, advantages and disadvantages to the options, and a recommendation. 3.1 POLICY ISSUE 1: Should the City be Eligible to Use the Mitigation Banking Sites for Public Projects? 3.1.1 s�sye- Under the current City of Renton Wetland Ordinance, a wide range of city-sponsored activities can occur in wetlands without obtaining a special permit. These activities are outlined in the City of Renton Wetland Management Ordinance (City of Renton 1992), Section 4-32-4 and include: • Activities affecting a single, hydrologically isolated Category 1 or 2 etland of less than 2,200 sq ft within a property boundary (City of Renton 199 ode Section 4-32-4.C.1). • Activities affecting hydrologically isolated Category 3 wetlands of less than 5,000 sq ft within a property boundary (City of Renton 1992; Code Section 4-32-4.C.2). • Normal and routine maintenance and repair of existing facilities where no alteration of the wetland or additional fill materials will be placed (City of Renton 1992; Code Section 4-32-4.A.4). The area must be restored to original conditions. • Normal and routine maintenance and repair with minimum placement of fill to bring facility up to established safety standards(City of Renton 1992; Code Section 4-32-4.A.5). Impact must be minimized and area restored. • Site investigation work necessary for land use application submittals such as surveys, soil logs, percolation tests, and other related activities (City of Renton 1992; Code Section 4- 32-4.A.8). • New surface water discharges to Category 1, 2, and 3 wetlands where discharge meets Chapter 22 of the City's Storm and Surface Water Drainage Ordinance. These activities will not result in significant changes in water temperature or chemical characteristics, and any changes in hydrology that would result in greater wetland function and value (City of Renton 1992; Code Section 4-32-4.A.9). Parametric, Inc. 10 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin • Regional storm water management facilities designed consistent with the Washington State Department of Ecology's Wetlands and Storm Water Management Guidelines (City of Renton 1992; Code Section 4-32-4.A.12). • Enlargement of facilities beyond existing needs provided footprint does not increase more than 10 percent within the wetland or its buffer(City of Renton 1992; Code Section 4-32- 4.C.6). • Emergency activities (City of Renton 1992; Code Section 4-32-4.D). As outlined above, the Wetlands Management Ordinance (City of Renton 1992) allows for a wide range of city-sponsored public activities without needing to compensate for the temporary or minor disturbance to wetlands. However,there are other public projects(e.g.,transportation,road improvements, public works) that the City may consider in the near and long term whose impacts to wetlands may require compensatory mitigation as per the City's Wetland Management Ordinance and/or state and federal wetland regulations. These impacts could be compensated for through the use of the proposed mitigation banking program. 3.1.2 Options 3.1.2.1 Option 1: Allow public project impacts to be mitigated for at the 1 mitigation banking sites (assumes that the public project meets the eligibility requirements for using the mitigation banking program) Advantages • The City would not have to necessarily provide on-site mitigation. • The City would not have to necessarily acquire additional land to implement an off-site mitigation design. • State and Federal regulatory agency acceptance of the credibility of the mitigation banking program could increase with City participation. • Allowing public projects to be eligible provides an opportunity for a partnership between public and private developers. Disadvantages • The amount of available "banked" wetland mitigation on the sites may diminish relatively fast if numerous public projects that affect higher quality wetlands (i.e., Category 1 and Parametrix, Inc. I1 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag.pin 2 wetlands) are implemented and are mitigated for at the mitigation banking sites (i.e., less banked wetland credit available for use by the private sector). • There is the potential that the general public may perceive the City as giving preferential treatment to meeting the eligibility requirements for public projects. 3.1.2.2 Option 2: Do not allow public project impacts to be mitigated for at the mitigation banking sites. Advantages • Leaves more "banked" wetland available for private projects. • There may be more public interest in the mitigation banking program if it was designed just for the private sector. Disadvantages • The City would need to acquire land to conduct off-site mitigation for public projects if on-site mitigation could not be achieved. • The City would not be able to take advantage of the mitigation banking program - a program to which they are committing substantial financial resources. • State and federal agencies may not be as supportive of the mitigation banking program if it is designed solely for the private sector. 3.1.3 Recommendation Comments from the general public (October 20, 1993) and the development community (October 21, 1993) were considered when making this recommendation. Considerations included the fact that public projects serve a public need benefiting the entire community, and that implementation of the mitigation banking program may be financed, in part, by the City (e.g., 5.33 acres of mitigation required for allowing fill on Glacier Park properties, Parks and Recreation trail development). We recommend that wetland mitigation for public projects that meet the eligibility requirements for using the mitigation banks be allowed on the mitigation banking sites. However, the City should consider limiting public participation to not exceed 50 percent (7.01 acres) of the total available mitigation banking acreage (14.02 after the 5.33 acres of mitigation for Glacier Park is subtracted from total acreage of 19.35), thereby providing at least 50 percent (7.01) of wetland mitigation banking available for private developments.[PUT IN FOOTNOTE HERE: Assumes that enhancement is not allowed. See Section 3.6, Policy Issue 6). Parametrix, Inc. 12 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin 3.2 POLICY ISSUE 2: Should the Mitigation Banking Sites be Used for Impacts to Category 1 and 2 Wetlands, or Only for Projects Impacting Category 3 Wetlands? 3.2.1 Issue In early conversations about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting Category 3 wetlands should be eligible to use the bank (Appendix A, Wetland Management Ordinance). The general reasoning was that this category represented the majority of wetlands within the Valley, and impacts would tend to occur on the smaller and lower value wetlands. A review of the Wetlands Management Ordinance and the current city wetland inventory indicates that some Category 1 and 2 wetlands could also be potentially eligible to use the bank. Deciding on whether to consider impacts to Category 1 and 2 wetlands eligible for use of the mitigation bank is dependent, in part, on (1) the number and acreage of Category 1, 2, and 3 wetlands within the Valley, and (2) interpretation of the City's Wetland Management Ordinance. Based on the available wetland inventory data there are 17 Category 3 wetlands ranging in size from less then 1 acre to about 20 acres, 15 Category 2 wetlands ranging in size from less than 1 acre to about 23 acres, and three Category 1 wetlands ranging in size from 20 to 65 acres. The City of Renton owns all of the Category 1 wetlands (Table 1, see Figure 1). �p The City's Wetland Management Ordinance is somewhat ambiguous with respect to whether �p Category 1 and 2 wetlands can be impacted. As currently interpreted, the ordinance does not preclude development activities in Category 1 and 2 wetlands; but it does not actually state that these wetlands can be altered, or state what activities are regulated in these higher quality wetlands. 3.2.2 Options: 3.2.2.1 Option 1: Allow the mitigation banking sites to be used for impacts only to Category 3 wetlands. Advantages • Potential impacts to Category 1 and 2 wetlands would be minimized if project proponents could not use the mitigation banking sites and had to do on-site and/or off-site mitigation (i.e., disincentive to impact Category 1 and 2 wetlands). • Ensures that only lower quality wetlands are being impacted, mitigated for, and replaced with greater functional value. Parametriz, Inc. 13 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Focusing the mitigation banking program on Category 3 wetlands may result in greater opportunities to retain and expand the City's economic base. • Administrative management of the mitigation banking program would be relatively simple. Disadvantage • Projects that may impact Category 1 (public only) and 2 (public and private) wetlands would not be eligible to use the wetland mitigation bank and would need to consider on- site and/or off-site mitigation alternatives. 3.2.2.2 Option 2: Allow the sites to be used for impacts to Category 1 and 2, as well as Category 3 wetlands. Advantages • Provides greater opportunity for the development community to use the mitigation banking program and does not necessarily preclude public and private development in Category 1 and 2 wetlands. • Provides opportunity for City to use the mitigation banking sites for impacts to Category 1 wetlands. Disadvantages • Potential to use up the acreage created for the bank relatively fast because of greater replacement-to-loss ratio prescribed by the City's Wetland Ordinance (City of Renton 1992) (i.e., potentially fewer users). • Higher value wetlands have higher buffer requirements, resulting in a net reduction in wetland mitigation area available for banking. 3.2.3 Recommendation Based on the available information on inventoried wetlands under the jurisdiction of the City of Renton, the majority of wetlands that may be subject to future development activities appear to be primarily a combination of both Category 2 and 3 wetlands, with Category 3 wetlands appearing to be more abundant than Category 2 wetlands. The majority of the Category 3 wetlands occur in the portion of the Valley where economic development is desirable. Therefore, it is reasonable to expect the majority of impacts to occur to Category 3 wetlands. Parametriz, Inc. 15 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin W Neither the general public nor the development community objected to allowing impacts to Category 2 wetlands being potentially compensated for at the mitigation banking sites. However, the general public did not want impacts to Category 1 wetlands to occur and be mitigated for on the mitigation banking sites. The City is currently the sole owner of Category 1 wetlands within the Black River Drainage Basin [with the exception of a portion (about 40 percent) of the Panther Creek Wetland]. Future public projects (e.g., extension of Oaksdale Avenue) may affect a portion of the adjacent Category 1 City of Renton Wetland (see Figure 1). Any impacts will need to be mitigated for according to the City of Renton's Wetland Management Ordinance (City of Renton 1992) and/or according to the Corps (and advisory state and federal resource agencies) permit conditions. The City should, at a minimum, have the opportunity to mitigate for those wetland impacts on the mitigation banking sites. Because it is unlikely that significant portions of City-owned Category 1 wetlands will be impacted, we recommend that compensating for ti impacts to Category 1 wetlands be allowed at the mitigation banking sites. We also recommend that the City consider allowing compensation for impacts to Category 2 as well as Category 3 4 wetlands to occur at the mitigation banking sites. The City needs to remember that any wetland under the jurisdiction of the Corps (and associated \ agencies such as the U.S. Environmental Protection Agency [EPA] and the Washington State Department of Ecology [Ecology]) are subject to federal and state regulatory requirements. The Corps and Ecology may not determine that compensation for impacts to a given wetland under their jurisdiction is appropriate at the mitigation banking sites. Finally, the section of the City's Wetland Management Ordinance on allowed and regulated activities (Section 4-32-4) is subject to broad interpretation for whether Category 1 and 2 wetlands can be impacted. Therefore, we recommend that the City request administrative clarification to determine whether the ordinance intended to allow impacts to Category 1 and 2 wetlands. 3.3 POLICY ISSUE 3: Should the Mitigation Banking Sites be Used for Impacts to Wetlands That are Less Than 1 Acre, or for Projects Impacting Wetlands Less Than 1 Acre or 1 Acre or Greater in Size? 3.3.1 Issue In early conversations with the City of Renton about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting wetlands of less than 1 acre, and considered to be above the headwaters, should be eligible to use the bank. The general reasoning for this was that any permitting decisions and requirements for mitigation would largely be a City Parametriz, Inc. 16 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin Q� J responsibility and impacts to these wetlands would not necessarily require a permit from the Corps' and/or Ecology'. s `�. However, there are wetlands within the Valley that are larger than 1 acre and a developer (public or private) may determine that unavoidable impacts to a proposed project are going to impact greater than 1 acre of wetland. For impacts to wetlands greater than 1 acre, a permit (either a Nationwide 26 permit for above the headwaters or isolated wetlands or Section 404 individual S permit for adjacent wetlands) to fill the wetland is required from the Corps and/or Ecology. 3.3.2 Options: 3.3.2.1 Option 1: Allow the mitigation banking sites to be used for impacts only to wetlands that are less than 1 acre and above the headwaters. Advantages • The City is the primary agency involved in permitting these types of activities and with working with the development community to determine appropriate compensatory mitigation. • Reduces the level of coordination necessary with state and federal resource and regulatory agencies, thus reducing the time invested in the administrative and technical management of the mitigation banking program. Disadvantages • May preclude a project proponent(public or private) from being able to use the mitigation banking site if other state and federal permit requirements could be met for wetlands 1 acre or larger. • If the Corps determines that many of the wetlands in the Valley are adjacent, the wetlands that would be eligible to use the site would shift to the upper drainage basin areas. These z We are assuming that some of the wetlands within the Valley that are less than 1 acre are indeed wetlands that are above the headwaters, thereby allowing the City to be the sole agency managing activities in those wetlands and the wetland mitigation banks. Should the Corps determine that the majority of wetlands within the Valley are "adjacent," the usefulness of a City managed wetland mitigation banking program will need to be addressed. ' The Corps and Ecology should be notified when a project is going to impact a wetland that is less than 1 acre and above the headwaters. The Corps will typically issue a jurisdictional letter and/or a Nationwide 26 permit. However, the Corps and Ecology have not typically required mitigation for impacts to wetlands that are less than 1 acre and above the headwaters. Parametriz, Inc. 17 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin areas are often considered to be of higher value because they are less disturbed and are often associated with primary and secondary stream tributaries. 3.3.2.2 Option 2: Allow the sites to be used for impacts to wetlands that are less than 1 acre in size and 1 acre or greater in size that are either above the headwaters or adjacent. Advantage • Provides an opportunity for project proponents (private or public) that can meet state and federal regulatory requirements to potentially use the mitigation banking site.4 Disadvantages • The wetland mitigation banking credit could potentially be used by one large project, thereby limiting opportunities for others who develop in the Valley. • An investment of time and resources may be needed to coordinate and negotiate an agreement with state and federal resources agencies. • Agencies (i.e., Ecology, EPA)require higher-value wetlands to have larger buffers. These buffer requirements may need to be met on the mitigation banking sites, thereby reducing the total available wetland acreage. • Up-front costs for the mitigation banking program could potentially increase. • State and federal agencies may have a difficult time agreeing that mitigation on the banking sites will be adequate compensatory wetland mitigation. 3.3.3 Recommendation The project team recommends that wetlands that are less than 1 acre and above the headwaters be eligible to use one of the two mitigation banking sites (e.g., Mitigation Banking Site 2). As envisioned, impacts to less than 1 acre of either Category 1, 2, or 3 wetlands that are considered ' Impacts to wetlands that are under federal jurisdiction need to be substantiated by meeting the alternatives analysis Section 404 (13)(1) guidelines of the Clean Water Act. The basic presumption of the alternatives analysis is that there is a less environmentally damaging practicable alternative to a project that is not dependent on water, including wetlands. Thus, depending on the type of project, it is unlikely that many project proponents who want to develop wetlands within the Valley could pass the alternatives analysis. If this assumption is true then it is likely that few impacts from projects that are subject to the federal requirements could potentially be offset at the mitigation banking sites. Parametrix, Inc. 18 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin to be above the headwaters would be permitted (including mitigation requirements) primarily by the City of Renton and mitigated for at one of the two mitigation banking sites. However, if a project proponent can meet the state and federal regulatory requirements associated with activities affecting wetlands [e.g., Section 404 (B)(1) alternatives analysis of the Clean Water Act], and the agencies, including the City of Renton agree that mitigation banking is the best compensatory mitigation option, the impacts could be offset at the other of the two mitigation banking sites. Under this scenario, the City of Renton may not necessarily need to meet and negotiate a Memorandum of Agreement with the federal and state resource agencies that also have regulatory oversight of the wetlands. However, the City will need to participate in the evaluation process with the state and federal agencies to determine if the mitigation banking site is the best option to compensate impacts to wetlands 1 acre or greater that are above the headwaters or adjacent. To ensure that sufficient wetland banking credits are available at the two mitigation banking sites, we further recommend that the mitigation banking program give preference to projects that impact less than 1 acre of Category 1, 2, or 3 wetlands that are above the headwaters. Adequacy for using the mitigation banking sites would need to be determined for projects that affect 1 acre or more of wetland. This concept is illustrated below in Table 2. Table 2. Recommended preference for allowing impacts to be compensated for at the mitigation banking sites. fa h` /� h•Nj /Kri��/'� �r+�c� 44 n A,,,-k � c /7 �s Lt� 41 Size Priority Wetland Category (acres) Jurisdictional Status 1 Category 3 <1 above the headwaters 2 Category 2 <1 above the headwaters 3 Category 1 <1 above the headwaters 4 Category 3 >_1 above the headwaters or adjacent 5 Category 2 >_1 above the headwaters or adjacent 6 Category 1 >_1 above the headwaters or adjacent Parametrix, Inc. 19 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3.4 POLICY ISSUE 4: Should the City be Solely Responsible for Administrative and Technical Management of the Mitigation Banking Program and Mitigation Banking Sites? 3.4.1 Issue The overall management of a mitigation banking program includes an administrative and technical management component. In general, administrative management includes: • Establishing the administrative agent • Credit brokering and credit tracking • Collecting and tracking fees • Financial issues and funding • Permit tracking • Being the bank operator (day-to-day management) In general, technical management of the sites includes: • Determining whether the project is suitable to use the mitigation banking program • Monitoring credit evaluation • Site maintenance • Implementing contingency actions • Oversight of site construction The commitment of individual(s) and time to manage the mitigation banking program requires, at a minimum, that the individual(s) be knowledgeable about permitting(local, state, and federal), wetland delineation, functional monitoring evaluations, financial management, and public relations. Currently, the City of Renton has staff with experience and expertise in evaluating SEPA checklists, permit applications, fiscal and financial (permit fee tracking) management, and public relations. However, it is the project team's understanding that the City requests technical wetland expertise from Ecology regarding SEPA checklists/permit applications that affect wetlands, wetland delineations, and mitigation plans. Parametrix, Inc. 20 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3.4.2 Options 3.4.2.1 Option 1: The City of Renton is the sole administrative and technical manager of the mitigation banking program and mitigation banking sites. Advantages • Typically programs that are administered and managed by one entity are more efficient and coordinated. • Project proponents have a greater sense of predictability associated with how the program works. • There may be reduced costs if the program were managed by the City. • The City would benefit from the technical knowledge it gains on mitigation banking; this could be used when developing other mitigation banking sites within the City. • The City engenders a level of trust and credibility with the users of the mitigation banking program because of the City's administrative and technical knowledge. Disadvantages • It may be difficult for the City to keep abreast of the growing body of knowledge regarding wetland creation, restoration, functional assessment, and monitoring techniques that may be applicable to the mitigation banking program. • The City will need at least one staff person who is knowledgeable about technical issues, administrative and financial management, public relations, and permitting. This person would need to b dedicated 100�pe—radm to the program. /fit 3.4.2.2 Option 2: The City of Renton is the administrative manager of the mitigation banking program and contracts out the technical management components of the program. Advantages • May ultimately be less expensive to contract out for technical management (i.e., monitoring, site maintenance, assistance with evaluating permit/SEPA applications, site visits to assess impacts to wetlands, review of wetland delineation reports, etc). Parametrix, Inc. 21 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Potentially more technical expertise is available from contractors that can benefit the program. • Allows the City to focus on the administrative management functions, oversee the contractor(s), and day-to-day management responsibilities. Disadvantages • City has to manage one or more contractors. • City may potentially lose knowledge to be gained because of indirect participation in the \,+� technical management components of the program. 3.4.3 Recommendation �r The City should consider hiring a contractor/consultant for at least the first 2 or 3 years of the w program, from site development through site monitoring for two reasons: (1) there may be a perception among the regulated community and general public that the City should not be the developer of the program, manager of the program, and user of the program without involving an objective party, and (2) the City can benefit from the technical expertise of contractors and consultants that have experience in monitoring, functional assessment, review and verification of �y wetland delineations and reports, etc. If this recommendation is accepted, the designated staff person from the City that will be the administrative manager of the program should maintain an \J �� active role in the technical management components of the program so tea the City could eventual the technic of the sites. We also—recommend],irrespective of the c o Q options that the City does not rely solely on Ecology for technical assistance with projects that ay potentially use the wetland miti ation banking program. T4, We also recommend that the City develop a simple mdch;iism to notify the Corps when the City is allowing a project proponent to use the mitigation banking site that will allow mitigation for O,V,�e ��o impacts to wetlands less than 1 acre that area considered to be above the headwaters (activities for altering those wetlands are authorized by the Corps Nationwide 26 permit process). The �J purpose of establishing a mechanism is to provide the Corps with information on what the City &J"Is requiring for mitigation associated with filling wetlands. Notifying the Corps of City actions will allow the Corps to have a record in the event that they are contacted about a potential fill S viojation. The mechanism would include: �� �.r AW,1 1. Identifying one individual in the Corps regulatory division and one individual at the City of Renton to be the point of contact for this program. 2. The City requiring a project proponent to submit a copy of the Corps' letter on the jurisdictional determination of the wetland(for sites without specific project plans), a copy Parametrix, Inc. I Y 22 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin of the Nationwide Permit, or the Letter of Authorization (for sites with specific project plans), before the City allows the project proponent to use the mitigation banking program 4 (this is one of the proposed eligibility requirements). 3. The City then preparing a form letter that references the Nationwide Permit number, the Letter of Authorization, or the Corps letter and which indicates that the City intends to allow the project proponent to use the mitigation banking site(s) to offset losses to { wetland resources. The letter would, at a minimum, include a description of the impact (e.g., location, size) and a summary of total wetland acreage available on the mitigation banking sites, total acreage used by the specific project and the total mitigation banking acreage remaining. The form letter should be sent to the designated contact person at the Corps for their files and for its office of law enforcement. G 1,�r}t, ✓�a�,w,W��n 3.5 POLICY ISSUE 5: Should the City Consider Exempting Category 3 Wetlands �"•"- �- � From the Sequencing Process(i.e.,Avoidance,Minimization a its Compensation) Currently Required by the City's Interim " "L Wetlands Ordinance? 3.5.1 Issue Currently the City of Renton's Wetland Management Ordinance requires that impacts to Category 1, 2, and 3 wetlands from development projects first be avoided and then minimized. Once project impacts have been avoided and minimized, any unavoidable impacts are then compensated. This process is typically referred to as sequencing of project impacts. This sequencing process is consistent with state and federal policies and regulations for wetland protection and management. 3.5.2 Options 3.5.2.1 Option 1: The City exempts Category 3 wetlands from sequencing.' Advantages • Eliminates one procedure of the City's Wetland Ordinance with which project proponents need to comply. • Potentially reduces time spent in project design. J L ' This option assumes that only Category 3 wetlands of less than 1 acre that are above the headwaters would be exempt, because any wetland impact subject to state and federal regulatory requirements would require sequencing. Parametrix, Inc. 23 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Potentially provides added incentive for developers wanting to locate/build industrial, commercial, and residential developments in the Valley. • Provides flexibility to project proponent in site planning and design. Disadvantages • Only Category 3 wetlands under the primary jurisdiction of the City could be exempt (wetlands under state/federal regulations would still be subject to sequencing). • Does not preclude developer from getting a jurisdictional determination from the Corps. • Special features of the site (i.e., provides flood storage) may make exemption disadvantageous to achieving the policy of no net loss of wetlands and wetland functions. 3.5.2.2 Option 2: The City does not exempt Category 3 wetlands. Advantage • All wetlands, whether they are governed by local, state, or federal regulations, are considered equal with respect to sequencing of project impacts. Disadvantage • Potentially may reduce economic incentive for developing lower quality Category 3 wetlands. 3.5.3 Recommendation While exempting certain Category 3 wetlands from the sequencing process would be viewed as advantageous for site developers, we recommend that the City continue to require sequencing of impacts for all wetlands, at least during the first year or two of the mitigation banking program, for three reasons: 1. Some of the development community and general public may perceive inequality in how wetland impacts are evaluated by the City. 2 2. Some Category 3 wetlands of less than 1 acre (that are above the headwaters) may provide a relatively significant function whose impact may affect achieving the policy of no net loss. Parametric, Inc. 24 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin 3. Potentially, the time required by the mitigation banking program manager to track and manage exempted wetlands may increase, and result in increased administrative costs. We also recommend that the City reevaluate the option of exempting Category 3 wetlands less than 1 acre that are above the headwaters once the program has been implemented and operating for 1 to 2 years. At that time it can be determined whether exempting certain Category 3 wetlands can be done equitably and with minimal paperwork. 3.6 POLICY ISSUE 6: Should the City Consider Modifying the Existing Interim Wetlands Management Ordinance to Recognize Enhancement as an Acceptable Form of Compensatory Mitigation? The City's Wetland Management Ordinance does not currently recognize enhancement as a compensatory mitigation option [City of Renton 1992; Code Section 4-32-6(b)(1)], because at the time the ordinance was developed the City decided that enhancement was difficult to define—and the City lacked the technical expertise necessary to determine if enhancement actually occurred. In general, enhancement is considered to mean those actions that are taken to improve upon or establish new functions within an existing wetland. 3.6.1 Options 3.6.1.1 Option 1: The City modifies the interim Wetland Management Ordinance to recognize enhancement as an acceptable form of compensatory mitigation. Advantages • Provides an additional compensatory option for developers to consider. • Increases the acreage (approximately 10 to 15 acres) available on the mitigation banking sites that could be used as credits in the mitigation banking program. • Establishes consistency with other local, state, and federal wetland mitigation programs (most recognize enhancement as one of several compensatory mitigation options). Disadvantages • The City will need to define enhancement, establish criteria that will evaluate the success of enhancement, and develop technical expertise to determine when a wetland has been enhanced. Parametriz, Inc. 25 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtigpin • The City's ordinance would need to be revised to reflect that mitigation of wetland impacts is based on acreage as well as function. • Anyone proposing enhancement actions on an existing wetland may be subject to local, state, and federal regulations regarding altering wetlands. - k�,- 'rl^- AA- & 3.6.1.2 Option 2: The City does not modify the interim Wetland Management Ordinance to recognize enhancement. Advantages • The City would not necessarily need to modify the existing ordinance, define enhancement, or acquire expertise to determine when enhancement actions have been successful. Disadvantages • Minimizes opportunities for on-site mitigation actions that could potentially increase or improve upon wetland functions. • Existing wetlands on the mitigation banking sites could not be altered to increase their functional value. 3.6.2 Recommendation We recommend that the City consider modifying the existing Wetlands Management Ordinance to include enhancement action as a wetland mitigation option, for the following reasons: 1. Potentially, many developments would consider enhancement options either on-site or at the mitigation banking sites. 2. Actions could be taken on the mitigation banking sites to improve upon some of the existing wetland communities by either the City or private developers. 3. Enhancement provides an opportunity to fulfill some of the objectives and policies of the mitigation banking program. If the City agrees with this recommendation, the mitigation banking program could incorporate enhancement at a later date - modification of the ordinance would not necessarily need to occur before the mitigation banking program is adopted and implemented. Modification could occur when the City adopts final critical areas ordinances according to schedules determined through the Growth Management Act (Due in 1994). However, modification of the ordinance prior Parametrix, Inc. 26 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmag pin to or concurrently with the mitigation banking program would provide an opportunity for the City to undertake enhancement actions concurrently with restoration of wetlands on the mitigation banking sites. This would result in a more integrated approach to establishing higher values and functions on the mitigation banking sites, and may result in long-term cost savings (versus independent on-site modifications after the uplands on the mitigation banking sites have been restored to wetlands). )TIn 0 � ew Parametrix, Inc. 27 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmug pin CHAPTER 3. POLICY ISSUES During discussions between the City and the project team, several policy issues were identified that require discussion and resolution by the City. The issues are identified below, followed by a brief discussion of the issue, options to resolve the issue, advantages and disadvantages to the options, and a recommendation. 3.1 POLICY ISSUE 1: Should the City be Eligible to Use the Mitigation Banking Sites for Public Projects? 3.1.1 h e � qu Under the current City of Renton Wetland Ordinance, a wide range of city-sponsored activities can occur in wetlands without obtaining a special permit. These activities are outlined in the City of Renton Wetland Management Ordinance (City of Renton 1992), Section 4-32-4 and include: • Activities affecting a single, hydrologically isolated Category 1 or 2 wetland of less than 2,200 sq ft within a property boundary (City of Renton 1992; Code Section 4-32-4.C.1). • Activities affecting hydrologically isolated Category 3 wetlands of less than 5,000 sq ft within a property boundary (City of Renton 1992; Code Section 4-32-4.C.2). • Normal and routine maintenance and repair of existing facilities where no alteration of the wetland or additional fill materials will be placed (City of Renton 1992; Code Section 4-32-4.A.4). The area must be restored to original conditions. • Normal and routine maintenance and repair with minimum placement of fill to bring facility up to established safety standards(City of Renton 1992; Code Section 4-32-4.A.5). Impact must be minimized and area restored. • Site investigation work necessary for land use application submittals such as surveys, soil logs, percolation tests, and other related activities (City of Renton 1992; Code Section 4- 32-4.A.8). • New surface water discharges to Category 1, 2, and 3 wetlands where discharge meets Chapter 22 of the City's Storm and Surface Water Drainage Ordinance. These activities will not result in significant changes in water temperature or chemical characteristics, and any changes in hydrology that would result in greater wetland City of Renton 1992; Code Section 4-32-4.A.9). �h ;� pw,,,�,�y,�, Uo�u..F.Lc.c_J r Parametriz, Inc. 10 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmog.pin • Regional storm water management facilities designed consistent with the Washington State Department of Ecology's Wetlands and Storm Water Management Guidelines (City of Renton 1992; Code Section 4-32-4.A.12). • Enlargement of facilities beyond existing needs provided footprint does not increase more than 10 percent within the wetland or its buffer (City of Renton 1992; Code Section 4-32- 4.C.6). • Emergency activities (City of Renton 1992; Code Section 4-32-4.D). As outlined above, the Wetlands Management Ordinance(City of Renton 1992) allows for a wide `� range of city-sponsored public activities without needing to compensate for the temporary or minor disturbance to wetlands. However,there are other public projects(e.g.,transportation,road improvements, public works) that the City may consider in the near and long term whose impacts to wetlands may require compensatory mitigation as per the City's Wetland Management Ordinance and/or state and federal wetland regulations. These impacts could be compensated for through the use of the proposed mitigation banking program. 3.1.2 Options 3.1.2.1 Option 1: Allow public project impacts to be mitigated for at the mitigation banking sites (assumes that the public project meets the eligibility requirements for using the mitigation banking program) Advantages • The City would not have to�ecessarilyprovide on-site mitigation. • The City would not have to ecessari cquir additional land to implement an off-site mitigation design. • State and Federal regulatory agency acceptance of the credibility of the mitigation banking program could increase with City participation. • Allowing public projects to be eligible provides an opportunity for a partnership between public and private developers. Disadvantages • The amount of available "banked" wetland mitigation on the sites may diminish relatively fast if numerous public projects that affect higher quality wetlands (i.e., Category 1 and Parametrix, Inc. 11 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 2 wetlands) are implemented and are mitigated for at the mitigation banking sites (i.e., less banked wetland credit available for use by the private sector). • There is the potential that the general public may perceive the City as giving preferential treatment to meeting the eligibility requirements for public projects. 3.1.2.2 Option 2: Do not allow public project impacts to be mitigated for at the mitigation banking sites. P4-k O PTto N Advantages • Leaves more "banked" wetland available for private projects. • There may be more public interest in the mitigation banking program if it was designed just for the private sector. Disadvantages • The City would need to acquire land to conduct off-site mitigation for public projects if on-site mitigation could not be achieved. • The City would not be able to take advantage of the mitigation banking program - a program to which they are committing substantial financial resources. • State and federal agencies may not be as supportive of the mitigation banking program if it is designed solely for the private sector. 3.1.3 Recommendation Comments from the general public (October 20, 1993) and the development community (October 21, 1993) were considered when making this recommendation. Considerations included the fact that public projects serve a public need benefiting the entire community, and that implementation of the mitigation banking program may be financed, in part, by the City (e.g., 5.33 acres of mitigation required for allowing fill on Glacier Park properties, Parks and Recreation trail development). We recommend that wetland mitigation for public projects that meet the eligibility requirements for using the mitigation banks be allowed on the mitigation banking sites. However, the City should consider limiting public participation to not exceed 50 percent-(7.0I acres) of thee` total available mitigation banking acrea 02 after the 5.33 acres of mitigation for Glacier ci Park is subtracted from total acreage o 19.35 thereby providing at least 50 percent (7.01) of wetland mitigation banking available f developments.[PUT IN FOOTNOTE HERE: Assumes that enhancement is not allowed. See Section 3.6, Policy Issue 6). Parametrix, Inc. 12 City of Renton - DRAFT + 55-1779-07 November 11, 1993".0 drftmtig.pin A_411 i 9 - �. C (V 3.2 POLICY ISSUE 2: Should the Mitigation Banking Sites be Used for Impacts to Category 1 and 2 Wetlands, or Only for Projects Impacting Category 3 Wetlands? 3.2.1 Issue In early conversations about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting Category 3 wetlands should be eligible to use the bank (Appendix A, Wetland Management Ordinance). The general reasoning was that this category represented the majority of wetlands within the Valley, and impacts would tend to occur on the smaller and lower value wetlands. A review of the Wetlands Management Ordinance and the current city wetland inventory indicates that some Category 1 and 2 wetlands could also be potentially eligible to use the bank. Deciding on whether to consider impacts to Category 1 and 2 wetlands eligible for use of the mitigation bank is dependent, in part, on (1) the number and acreage of Category 1, 2, and 3 wetlands within the Valley, and (2) interpretation of the City's Wetland Management Ordinance. Based on the available wetland inventory data there are 17 Category 3 wetlands ranging in size from less then 1 acre to about 20 acres, 15 Category 2 wetlands ranging in size from less than 1 acre to about 23 acres, and three Category 1 wetlands ranging in size from 20 to 65 acres. The City of Renton owns all of the Category 1 wetlands (Table 1, see Figure 1). The City's Wetland Management Ordinance is somewhat ambiguous with respect to whether Category 1 and 2 wetlands can be impacted. As currently interpreted, the ordinance does not preclude development activities in Category 1 and 2 wetlands; but it does not actually state that these wetland* can be altered, or state what activities are regulated in these higher quality wetlands. Ca.,- � d 3.2.2 Options: 3.2.2.1 Option 1: Allow the mitigation banking sites to be used for impacts only to Category 3 wetlands. Advantages • Potential impacts to Category 1 and 2 wetlands would be minimized if project proponents could not use the mitigation banking sites and had to do on-site and/or off-site mitigation (i.e., disincentive to impact Category 1 and 2 wetlands). • Ensures that only lower quality wetlands are being impacted, mitigated for, and replaced with greater functional value. Parametrix, Inc. 13 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Focusing the mitigation banking program on Category 3 wetlands may result in greater opportunities to retain and expand the City's economic base. • Administrative management of the mitigation banking program would be relatively simple. Disadvantage • Projects that may impact Category 1 (public only) and 2 (public and private) wetlands would not be eligible to use the wetland mitigation bank and would need to consider on- site and/or off-site mitigation alternatives. 3.2.2.2 Option 2: Allow the sites to be used for impacts to Category 1 and 2, as well as Category 3 wetlands. Advantages • Provides greater opportunity for the development community to use the mitigation banking program and does not necessarily preclude public and private development in Category 1 and 2 wetlands. • Provides opportunity for City to use the mitigation banking sites for impacts to Category 1 wetlands. Disadvantages • Potential to use up the acreage created for the bank relatively fast because of greater replacement-to-loss ratio prescribed by the City's Wetland Ordinance (City of Renton 1992) (i.e., potentially fewer users). • Higher value wetlands have higher buffer requirements, resulting in a net reduction in wetland mitigation area available for banking. SM vv „ 3.2.3 Recommendation Based on the available information on inventoried wetlands under the jurisdiction of the City of Renton, the majority of wetlands that may be subject to future development activities appear to be primarily a combination of both Category 2 and 3 wetlands, with Category 3 wetlands appearing to be more abundant than Category 2 wetlands. The majority of the Category 3 wetlands occur in the portion of the Valley where economic development is desirable. Therefore, it is reasonable to expect the majority of impacts to occur to Category 3 wetlands. Parametrix, Inc. 15 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin Neither the general public nor the development community objected to allowing impacts to Category 2 wetlands being potentially compensated for at the mitigation banking sites. However, the general public did not want impacts to Category 1 wetlands to occur and be mitigated for on the mitigation banking sites. The City is currently the sole owner of Category 1 wetlands within the Black River Drainage Basin [with the exception of a portion (about 40 percent) of the Panther Creek Wetland]. Future public projects (e.g., extension of Oaksdale Avenue) may affect a portion of the adjacent Category 1 City of Renton Wetland (see Figure 1). Any impacts will need to be mitigated for according to the City of Renton's Wetland Management Ordinance(City of Renton 1992) and/or according to the Corps (and advisory state and federal resource agencies) permit conditions. The City should, at a minimum, have the opportunity to mitigate for those wetland impacts on the mitigation banking sites. Because it is unlikely that significant portions of City-owned Category 1 wetlands will be impacted, we recommend that compensating for impacts to Category 1 wetlands be allowed at the mitigation banking sites. We also recommend that the City consider allowing compensation for impacts to Category 2 as well as Category 3 wetlands to occur at the mitigation banking sites. The City needs to remember that any wetland under the jurisdiction of the Corps (and associated agencies such as the U.S. Environmental Protection Agency [EPA] and the Washington State Department of Ecology [Ecology]) are subject to federal and state regulatory requirements. The Corps and Ecology may not determine that compensation for impacts to a given wetland under their jurisdiction is appropriate at the mitigation banking sites. Finally, the section of the City's Wetland Management Ordinance on allowed and regulated activities (Section 4-32-4) is subject to broad interpretation for whether Category 1 and 2 wetlands can be impacted. Therefore, we recommend that the City request administrative clarification to determine whether the ordinance intended to allow impacts to Category 1 and 2 wetlands. Nee, 3.3 POLICY ISSUE 3: Should the Mitigation )flanking Sites de Vsed for Impacts to ct�l Wetlands That are Less Than 1 Acre, or for Projects Impacting Wetlands Less Than 1 Acre or 1 Acre or Greater in Size? 416� 3.3.1 Issue In early conversations with the City of Renton about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting wetlands of less than 1 acre, and considered to be above the headwaters, should be eligible to use the bank. The general reasoning for this was that any permitting decisions and requirements for mitigation would largely be a City Parametrix, Inc. 16 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmag pin responsibility and impacts to these wetlands would not necessarily require a permit from the Corps'` and/or Ecology'. However, there are wetlands within the Valley that are larger than 1 acre and a developer (public or private) may determine that unavoidable impacts to a proposed project are going to impact greater than 1 acre of wetland. For impacts to wetlands greater than 1 acre, a permit (either a Nationwide 26 permit for above the headwaters or isolated wetlands or Section 404 individual permit for adjacent wetlands) to fill the wetland is required from the Corps and/or Ecology. c moo/ 3.3.2 Options: 3.3.2.1 Option 1: Allow the mitigation banking sites to be used for impacts only to wetlands that are less than 1 acre and above the headwaters. Advantages • The City is the primary agency involved in permitting these types of activities and with working with the development community to determine appropriate compensatory mitigation. • Reduces the level of coordination necessary with state and federal resource and regulatory agencies, thus reducing the time invested in the administrative and technical management of the mitigation banking program. Disadvantages • May preclude a project proponent(public or private) from being able to use the mitigation banking site if other state and federal permit requirements could be met for wetlands 1 acre or larger. • If the Corps determines that many of the wetlands in the Valley are'adjacent the wetlands kt that would be eligible to use the site would shift to the upper drainage basin areas. These a� 2 We are assuming that some of the wetlands within the Valley that are less than 1 acre are indeed wetlands that 40� are above the headwaters, thereby allowing the City to be the sole agency managing activities in those wetlands and the wetland mitigation banks. Should the Corps determine that the majority of wetlands within the Valley are "adjacent," the usefulness of a City managed wetland mitigation banking program will need to be addressed. } ' The Corps and Ecology should be notified when a project is going to impact a wetland that is less than 1 acre and above the headwaters. The Corps will typically issue a jurisdictional letter and/or a Nationwide 26 permit. However, the Corps and Ecology have not typically required mitigation for impacts to wetlands that are less than 1 acre and above the headwaters. Parametrix, Inc. 17 City of Renton - DRAFT 5 -1779-07 November 11, 1993 drftmtig.pin areas are often considered to be of higher value because they are less disturbed and are often associated with primary and secondary stream tributaries. -e- gip.-^e j '^` ) 4,e 3.3.2.2 Option 2: Allow the sites to be used for impacts to wetlands that are less than C-&�.? 1 acre in size and 1 acre or greater in size that are either above the headwaters or adjacent. Advantage • Provides an opportunity for project proponents (private or public) that can meet state and federal regulatory requirements to potentially use the mitigation banking site.' Disadvantages • The wetland mitigation banking credit could potentially be used by one large project, thereby limiting opportunities for others who develop in the Valley. ) fA • An investment of time and resources may be needed to coordinate and negotiate an agreement with state and federal resources agencies. • Agencies(i.e., Ecology, EPA)require higher-value wetlands to have larger buffers. These buffer requirements may need to be met on the mitigation banking sites, thereby reducing the total available wetland acreage. ----- - __ -- • Up-front costs for the mitigation banking program could potentially increase. • State and federal agencies may have a difficult time agreeing that mitigation on the banking sites will be adequate compensatory wetland mitigation. _dti-, d 3.3.3 Recommendation 4�y � The project team recommends that wetlands that are less than 1 acre and above the headwaters be eligible to use one of the two mitigation banking sites (e.g., Mitigation Banking Site 2). As envisioned, impacts to less than 1 acre of either Category 1, 2, or 3 wetlands that are considered ' Impacts to wetlands that are under federal jurisdiction need to be substantiated by meeting the alternatives analysis Section 404 (13)(1) guidelines of the Clean Water Act. The basic presumption of the alternatives analysis is that there is a less environmentally damaging practicable alternative to a project that is not dependent on water, including wetlands. Thus, depending on the type of project, it is unlikely that many project proponents who want to develop wetlands within the Valley could pass the alternatives analysis. If this assumption is true then it is likely that few impacts from projects that are subject to the federal requirements could potentially be offset at the mitigation banking sites. Parametriz, Inc. 18 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin to be above the headwaters would be permitted (including mitigation requirements) primarily by the City of Renton and mitigated for at one of the two mitigation banking sites. However, if a project proponent can meet the state and federal regulatory requirements associated with activities affecting wetlands [e.g., Section 404 (B)(1) alternatives analysis of the Clean ; Water Act], and the agencies, including the City of Renton agree that mitigation banking is the best compensatory mitigation option, the impacts could be offset at the other of the two mitigation banking sites. Under this scenario, the City of Renton may not necessarily need to meet and negotiate a Memorandum of Agreement with the federal and state resource agencies that also have regulatory oversight of the wetlands. However, the City will need to participate in the evaluation process with the state and federal agencies to determine if the mitigation banking site is the best option to compensate impacts to wetlands 1 acre or greater that are above the headwaters or adjacent. To ensure that sufficient wetland banking credits are available at the two mitigation banking sites, we further recommend that the mitigation banking program give preference to projects that impact less than 1 acre of Category 1, 2, or 3 wetlands that are above the headwaters. Adequacy for using the mitigation banking sites would need to be determined for projects that affect 1 acre or more of wetland. This concept is illustrated below in Table 2. Table 2. Recommended preference for allowing impacts to be compensated for at the mitigation banking sites. Size Priority Wetland Category (acres) Jurisdictional Status 1 Category 3 <1 above the headwaters 2 Category 2 <1 above the headwaters 3 Category 1 <1 above the headwaters 4 Category 3 >1 above the headwaters or adjacent 5 Category 2 >_1 above the headwaters or adjacent 6 Category 1 >_1 above the headwaters or adjacent ,CYL✓vC G�_� ram, Parametrix, Inc. 19 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3.4 POLICY ISSUE 4: Should the City be Solely Responsible for Administrative and Technical Management of the Mitigation Banking Program and Mitigation Banking Sites? 3.4.1 Issue The overall management of a mitigation banking program includes an administrative and technical management component. In general, administrative management includes: • Establishing the administrative agent • Credit brokering and credit tracking • Collecting and tracking fees • Financial issues and funding • Permit tracking • Being the bank operator (day-to-day management) In general, technical management of the sites includes: • Determining whether the project is suitable to use the mitigation banking program • Monitoring credit evaluation • Site maintenance • Implementing contingency actions • Oversight of site construction The commitment of individual(s) and time to manage the mitigation banking program requires, at a minimum, that the individual(s) be knowledgeable about permitting (local, state, and federal), wetland delineation, functional monitoring evaluations, financial management, and public relations. Currently, the City of Renton has staff with experience and expertise in evaluating SEPA checklists,permit applications, fiscal and financial (permit fee tracking) management, and Lw blic relations.1However, it is the project team's understanding thatt t a H requests tec ictland expertise from Ecology regarding SEPA checklists/permit applications that affect tlands, wetland delineations, and mitigation plans. \vtyf- Parametrix, Inc. .20 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin 3.4.2 Options 3.4.2.1 Option 1: The City of Renton is the sole administrative and technical manager of the mitigation banking program and mitigation banking sites. Advantages • Typically programs that are administered and managed by one entity are more efficient and coordinated. • Project proponents have a greater sense of predictability associated with how the program works. • There may be reduced costs if the program were managed by the City. • The City would benefit from the technical knowledge it gains on mitigation banking; this could be used vAmn-Aevc*ping other mitigation banking sites within the City. • The City engenders alevel of trust and credibility with the users of the mitigation banking program because of the City's administrative and technical knowledge. Disadvantages • It may be difficult for the City to keep abreast of the growing body of knowledge regarding wetland creation, restoration, functional assessment, and monitoring techniques that may be applicable to the mitigation banking program. • The City will need at least one staff person who is knowledgeable about technical issues, ' administrative and financial management, public relations, and permitting. This person would need to be dedicated 100 percent to the program. �. 3.4.2.2 Option 2: The City of Renton is the administrative manager of the mitigation L-N, banking program and contracts out the technical management components of the program. Advantages • May ultimately be less expensive to contract out for technical management (i.e., monitoring, site maintenance, assistance with evaluating permit/SEPA applications, site visits to assess impacts to wetlands, review of wetland delineation reports, etc). Parametrix, Inc. 21 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Potentially more technical expertise is available from contractors that can benefit the program. • Allows the City to focus on the administrative management functions, oversee the contractor(s), and day-to-day management responsibilities. Disadvantages • City has to manage one or more contractors. • City may potentially lose knowledge to be gained because of indirect participation in the technical management components of the program. 3.4.3 Recommendation � d The City should consider hiring a contractor/consultant for at least the first 2 or 3 years of the program, from site development through site monitoring for two reasons: (1) there may be a perception among the regulated community and general public that the City should not be the developer of the program, manager of the program, and user of the program without involving an objective party, and (2) the City can benefit from the technical expertise of contractors and consultants that have experience in monitoring, functional assessment, review and verification of wetland delineations and reports, etc. If this recommendation is accepted, the designated staff person from the City that will be the administrative manager of the program should maintain an active role in the technical management components of the program so that the City could eventually be the technical manager of the sites. We alsCrecommen ,,irrespectivd'bf the ch of'options thatthe City does not-rely solely on/ogy for technical issistancewith projects that may potentially use the wetland mit' ation Junking-'3r6gram. w ? t&�__[ a �We also recommend that the City develop a simple mechani to notify the Corps when the City ' is allowing a project proponent to use the mitigation banking site that will allow mitigation for impacts to wetlands less than 1 acre that area considered to be above the headwaters (activities for altering those wetlands are authorized by the Corps Nationwide 26 permit process). The purpose of establishing a mechanism is to provide the Corps with information on what the City is requiring for mitigation associated with filling wetlands. Notifying the Corps of City actions will allow the Corps to have a record in the event that they are contacted about a potential fill violation. The mechanism would include: 1. Identifying one individual in the Corps regulatory division and one individual at the City of Renton to be the point of contact for this program. 2. The City requiring a project proponent to submit a copy of the Corps' letter on the jurisdictional determination of the wetland(for sites without specific project plans), a copy Parametrix, Inc. --I l 22 City of Renton - DRAFT 55-1779-07 t`•� November 11, 1993 drftmtig pin /0 1 UT C,- KU_,5(- i of the Nationwide Permit, or the Letter of Authorizat on (for sites with specific project plans),before the City allows the project proponent to use the mitigation banking program (this is one of the proposed eligibility requirements). 3. The City then preparing a form letter that references the Nationwide Permit number, the Letter of Authorization, or the Corps letter and which indicates that the City intends to allow the project proponent to use the mitigation banking site(s) to offset losses to wetland resources. The letter would, at a minimum, include a description of the impact (e.g., location, size) and a summary of total wetland acreage available on the mitigation banking sites, total acreage used by the specific project and the total mitigation banking acreage remaining. The form letter should be sent to the designated contact person at the Corps for their files and for its office of law enforcement. 3.5 POLICY ISSUE 5: Should the City Consider Exempting Category 3 Wetlands From the Sequencing Process(i.e.,Avoidance,Minimization Compensation) Currently Required by the City's Interim Wetlands Ordinance? 3.5.1 Issue Currently the City of Renton's Wetland Management Ordinance requires that impacts to Category 1, 2, and 3 wetlands from development projects first be avoided and then minimized. Once project impacts have been avoided and minimized, any unavoidable impacts are then compensated. This process is typically referred to as sequencing of project impacts. This sequencing process is consistent with state and federal policies and regulations for wetland protection and management. 3.5.2 Options 3.5.2.1 Option 1: The City exempts Category 3 wetlands from sequencing.5 Advantages • Eliminates one procedure of the City's Wetland Ordinance with which project proponents need to comply. • Potentially reduces time spent in project design. ' This option assumes that only Category 3 wetlands of less than 1 acre that are above the headwaters would be exempt, because any wetland impact subject to state and federal regulatory requirements would require sequencing. Parametrix, Inc. 23 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin • Potentially provides added incentive for developers wanting to locate/build industrial, commercial, and residential developments in the Valley. • Provides flexibility to project proponent in site planning and design. Disadvantages • Only Category 3 wetlands under the primary jurisdiction of the City could be exempt (wetlands under state/federal regulations would still be subject to sequencing). • Does not preclude developer from getting a jurisdictional determination from the Corps. • Special features of the site (i.e., provides flood storage) may make exemption disadvantageous to achieving the policy of no net loss of wetlands and wetland functions. 3.5.2.2 Option 2: The City does not exempt Category 3 wetlands. Advantaee • All wetlands, whether they are governed by local, state, or federal regulations, are considered equal with respect to sequencing of project impacts. Disadvantaize • Potentially may reduce economic incentive for developing lower quality Category 3 wetlands. 3.5.3 Recommendation at-"-�A While exempting certain Category 3 wetlands from the sequencing process would be viewed as advantageous for site developers, we recommend that the City continue to require sequencing of impacts for all wetlands, at least during the first year or two of the mitigation banking program, for three reasons: 1. Some of the development community and general public may perceive inequality in how wetland impacts are evaluated by the City. 2. Some Category 3 wetlands of less than 1 acre (that are above the headwaters) may provide a relatively significant function whose impact may affect achieving the policy of no net loss. Parametrix, Inc. 24 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmag pin 3. Potentially, the time required by the mitigation banking program manager to track and manage exempted wetlands may increase, and result in increased administrative costs. We also recommend that the City reevaluate the option of exempting Category 3 wetlands less than 1 acre that are above the headwaters once the program has been implemented and operating 7� for T to 2 years. At that time it can be determined whether exempting certain Category 3 wetlands can be done equitably arA with minimal paperwork is-f<U k L L .6 POLICY ISSUE 6: Should the City Consider Modifying the Existing Interim Wetlands Management Ordinance to Recognize Enhancement as an Acceptable Form of Compensatory Mitigation? The City's Wetland Management Ordinance does not currently recognize enhancement as a compensatory mitigation option [City of Renton 1992; Code Section 4-32-6(b)(1)], because at the time the ordinance was developed the City decided that enhancement was difficult to define—and the City lacked the technical expertise necessary to determine if enhancement actually occurred. In general, enhancement is considered to mean those actions that are taken to improve upon or establish new functions within an existing wetland. 3.6.1 Options 3.6.1.1 Option 1: The City modifies the interim Wetland Management Ordinance to recognize enhancement as an acceptable form of compensatory mitigation. Advantages • Provides an additional compensatory option for developers to consider. Increases the acreage (approximately 10 to 15 acres) available on the mitigation banking sites that could be used as credits in the mitigation banking program. • Establishes consistency with other local, state, and federal wetland mitigation programs (most recognize enhancement as one of several compensatory mitigation options). Disadvantages ci. lclt-- _ / - G,4 be- The City will need to define enhancement, establish criteria that will evaluate the success of enhancement, and develop technical expertise to determine when a wetland has been enhanced. Parametrix, Inc. 25 City of Renton - DRAFT 55-1779-07 November 11, 1993 drftmtigpin • The City's ordinance would need to be revised to reflect that mitigation of wetland impacts is based on acreage as well as function. • Anyone proposing enhancement actions on an existing wetland may be subject to local, state, and federal regulations regarding altering wetlands. 3.6.1.2 Option 2: The City does not modify the interim Wetland Management Ordinance to recognize enhancement. Advantages • The City would not necessarily need to modify the existing ordinance, define enhancement, or acquire expertise to determine when enhancement actions have been successful. Disadvantages • Minimizes opportunities for on-site mitigation actions that could potentially increase or improve upon wetland functions. • Existing wetlands on the mitigation banking sites could not be altered to increase their functional value. t)O NCB >4 6 ki-_� W l` d T�hS C C�pi Cu,c S u-� 3.6.2 Recommendation 7 l J We recommend that the City consider modifying the existing Wetlands Management Ordinance to include enhancement action as a wetland mitigation option, for the following reasons: 1. Potentially, many developments would,consider enhancement options either on-site or at the mitigation banking sites. 2. Actions could be taken on the mitigation banking sites to improve upon some of the existing Ny�etland cc ties by either the City or private developers. "fig 4 3. Enhancement provides an opportunity to fulfill some of the objectives Und policies of the mitigation banking program. If the City agrees with this recommendation, the mitigation banking program could incorporate enhancement at a later date - modification of the ordinance would not necessarily need to occur before the mitigation banking program is adopted and implemented. Modification could occur when the City adopts final critical areas ordinances according to schedules determined through the Growth Management Act (Due in A 1994). However, modification of the ordinance prior Parametrix, Inc. 26 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtig.pin to or concurrently with the mitigation banking program would provide an opportunity for the City to undertake enhancement actions concurrently with restoration of wetlands on the mitigation banking sites. This would result in a more integrated approach to establishing higher values and functions on the mitigation banking sites, and may result in long-term cost savings (versus independent on-site modifications after the uplands on the mitigation banking sites have been restored to wetlands). 5 �L Parametrix, Inc. 27 City of Renton -DRAFT 55-1779-07 November 11, 1993 drftmtigpin JAN-17-94 MON 9:33 PARAMETRIX FAX NO. 206 889 8808 P. 01/09 Parametrix, Inc. 5808 Lake Washington Blvd. N.E. Kirkland, WA 98033 206-822-8880 FAX TRANSMISSION COVER PAGE FAX # 206-889-88013 To: .............................................. Fax#: From: ...ba ......................................... ................................ Date: ............._., Number of Pages (Total) ...I................................................ Comments: 1V2 ...........................................I-IN......ma y.......... �p o.-.....-��1`lr........................................................................................ .................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................... JAN-17-94 MON 9:34 PARAMETRIX FAX NO, 206 889 8808 P, 02/09 Many areas in the Valley that were filled over the past, 20 years were developed; however, some filled areas were not, and depressional areas on the undeveloped filled sites collected rainwater. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Sites 1 and 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. Mitigation Site 1, #14 Parcel Mitigation Banking Site 1 is 30.97 acres and consists of 18.78 acres of wetland (Figure 1). The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, upland shrub communities, and a fairly large forested wetland community consisting primarily of cottonwoods and shrubs. 040 Current and Existing Conditi ns ------- — At least one-third of Parcel 1 as either been cleared, o cleare -and filled, with gravel-an3I sand from 12 to 48 inches in depth (David Evans and Associates 1991), A 4-foot-high mound of fill material covers approximately 1 acre of the site. Currently the soils on-site are fill material; historically the site was characterized by three bATAf soil types: Puyallup fine sandy loam (non-hydric), Woodinville silt loam (hydric), and Puget silty clay loam (hydric). The non-hydric soil type is the: dominant underlying soil type and occurs largely in the central portion of the site and continues to the north and south of the site. The source of hydrology for the wetlands on Parcel 14 is precipitation, The wetlands occur in depressional areas that hold precipitation and leave the site by evapotranspiration and infiltration processes, The existing and current conditions are that the wetlands on Parcel 14 have formed on top of compact fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water t}o�Stp'ringbroo�k�,Creek. /�t f �_Lw_ �1 nFR � ✓I+ s�-y� U��v�AMI. ��� �IJ J"`�"c'!, � G """ lfN.s p'QC_�^-�-+�' N'1 �+ftd1r4 ACE. 15 � 6u Ee? rvrho 'ienrto( revtW� /� 6_4Theprepare for itigatzon an -mg Ites 1 and :? indicates awe man a e eveel�� can not be considered in establishing adjacency (i.e., The Corps determine whether the,"S�,-A,_,, � s wetlands would have formed or occur on the site in the absence of the levee). However,MOX-T I-IJ L the Corps must also look at current conditions. The levee has been in place since the 1950's , rNJfrt, and is presence is a historic and current condition; it ne�:ds to be considered in determining the jurisdictional status. renton/jurdsdu.ren January 17, 1994 JAN-17-94 MON 9:34 PARAMETRIX FAX N0, 206 889 8808 P, 03/09 Adjacent? The Corps considers the wetlands that comprise Mitigation Banking Site 1 (Parcel 14) to be adjacent because they are continuous with a large wetland parcel owned by the City of Renton (wetland W-12), immediately adjacent to Springbrook Creek (see Figure 1). The Corps MFR indicates that wetlands on Parcel 14 are adjacent because (1) they are contiguous with wetlands to the north and east (the Boeing and City of Renton wetlands); (2) the City of Renton wetlands extend over to Springbrook Creek; and (3) the City of Renton wetlands periodically experience flooding from Springbrook Creek, which in turn may back water into the ditch along the northern boundary of Parcel 14. The issues associated with the adjacency determination are outlined below, First, the MFR issued for Parcel 14 indicated that a jurisdictional determination for the site would require further analysis and that the man-made drainage ditch along the western edge of the site appears to be connected to an open water w;�-tland (the City of Renton wetland) and from there to Springbrook Creek.,-�T�he City found no direct connection between theme Qity of Renton wetland and $pringbrook Creek (based on survey in August 1993). ".o f i._14J0.7P, A drainage ditch occurs along the western boundary of the site and carries water from offsite, south of Parcel 14, around the western and northern boundary of Parcel 14. The water then drains into the Boeing wetland (W-13), north of the potential P-channel easement and Parcel 14 (see Figure 1). Once in wetland W-13, the water drains into a 48 inch culvert located under the extension of Oaksdale .Avenue and drains into the City of Renton wetland (W-12). e City of Renton wetland (W-12)/c6nsists of two-cells separated by a road. The elevation of the City of Renton wetland is 11#eet; the elevation of the road is 13 to 14 feet, The west cell has a ditch/culvert connection to the Boeing wetland (W-13). There is no culvert or , ►A ditch connection between the east and west cell of the City of Renton wetland', and hence ,1 no connection to Springbrook Creek. Once water ent(.rs into the west cell of the City of N' Renton wetland, it is retained within the wetland and leaves the site through evapotranspiration and infiltration. No direct outlet was found between the east cell of the' j p:'Se City of Renton wetland to Springbrook Creek. However, a ditch connects to a portion ofjc;)e the berm along Springbrook Creek- water could enter into the ditch from Springbrook Creek during a high flow event (14-ttf"14 feet based on 100-year event). Flood waters would need to increase the elevation of the east cell above 13 feet before it overtops the road and enters the west cell. 1The City of Renton Public Works maintenance crew conducted a site-visit in September 1993 to determine if a culvert was present between the west and east cell of W-12. Using a metal detector and uarioasrprobes no culvert or other type of connection between the two cells was found. 4691 renton/urisdic.ren January 17, 1994 JAN-I'(-94 MON 9:3b PAKAMETR1X FAX N0, 206 889 8808 P. 04/09 114 t to �54 This information indicates that under current conditions there is no direct regularly reoccurring surface connection between the east cell of the City of Renton wetland and Springbrook Creek, and no connection between the east and west cells. How can the wetlands on Parcel 14 be continuous with Springbrook Creek if there is no regular �o df connection (other then during a 100-year event) between Springbrook Creek and the east cell of W-12, and the elevation of the wetlands on Parcel 14 are 3 to 4 feet higher than wetland W-12? C„,.: _;ter �►� Second, the drainage ditch along the western boundari of the site that carries water from fj offsite, south of Parcel 14, around the western and northern boundary of Parcel 14. The water into the Boeing wetland (W-13), north of the potential P-channel easement and Parcel 1 is lower in elevation than the elevation of the wetlands on Parcel 14 by an estimated �� tofYfeet, The ditch does not currently provide a source of hydrology to the wetlands n Parcel 14. Although water entering the drainage ditch drains into the Boeing wetland (W- 13) and ultimately into the west cell of the City of Renton wetland, there is no evidence that the surface elevation of water in the ditch crests over the top of the ditch into the wetlands on Parcel 14. Without evidence of overtopping it is difficult to determine that there is a hydrologic connection between the wetlands on Parcel 14 and the City of Renton wetland. Thus, there is n inlet for water to drain from the west. cell of the City of Renton wetland into the Boeing Fetland, and into wetlands on Parcel 14 under current and existing conditions. , el„jlll� V'' IUnder current conditions, the lower elevation in the ditch and the lack of a direct connection between the City of Renton wetland and Springbrook Creek prevents water from Springbrook Creek from entering the City of Renton wetland, and hence the wetlands on Parcel 14. Third, as a result of filling activities, the elevation of the wetlands on parcel 14 are estimated to be at least 8 to 10 feet higher than the elevation of pringbrook Creek (using an elevation of about 8 feet based on average annual Jow),;and 2 to 4'''(eet higher than aL,,- high Springbrook Creek flow (using a high flow elevation of to 14 2 at SW 27th Street cf- c.,wv based on a 100-year storm event) (East Side Green River watersfie3Plan). In addition, the elevation of the wetlands on parcel 14 are estimated to e to;£eet higher than the City �'"`rs• of Renton wetland (W-11 and W-12). 051 mA14 A.-4 F"V i, F(A w-iZ,rIgAt is A 0/-r6$0AVCr /N The MFR indicates that the City of Renton wetland contained standing water and is likely flooded by high waters overbanking Springbrook Creek on a regular and periodic basis. The Art *A information available on elevations of the wetlands and the water level in Springbrook �s during a normal event and high flow event show that water from Springbrook Creek can ,r only get into the east cell of W-12 during a 100-year event-this can not be considered a)q-,+2-o" regular or periodic basis. The results of the FEQ simulations in the East Side Green River Watershed Plan indicate that wetlands W-11 and V&It provide substantial storage volume and reduce peak flow during a 100-year storm ever For example, as the culvert crossing renron/jurisdic.ren 7Z)..4vrr fUfL('/ A G7t A-1— S-'oAAd January 17, 1994 /iv WiSr c:Xc.(- . /C/VO4 FVA ybow, i vuu�o CeNl t- -Tvi /55uE, JAN-17-94 MON 9;36 PARAMETRIX FAX NO, 206 889 8808 P, 05/09 at Southwest 27th StreetAre�trrcts flow, the water surface elevation in Springbrook Creek rises and spills out into wetlands W-11 and W-12. As Springbrook Creek continues to rise these wetlands continue to fill and store a combined volume of approximately 240-acre feet for the 100-year flood. Thus, a 100-year storm event is required before there is a temporary hydrologic connection between Springbrook Creek and the City of Renton wetland. Even if the dike along Springbrook Creek were removed, a 100-year event would still be required before Springbrook Creek would flow over into the east Sell of the City of Renton wetland.V In addition, even if an assumption could be made that a 100-year event results in flooding of the east and west cell of the City of ReiiQn_wetland. the storage capacity of the City of 7 W, Renton wetland would have tohecome saturated bo e water backed up into the Boeing wetland (W-13), the ditch around)Parcel 14, and ultimately into Parcel 14. If it requires ate' 100-year event or greater for this to occur, it is reasonable to suggest that there is not a 504A-,g '` direct or continuous connection between the wetlands on Parcel 14, the Boeing`'VI 'City of A.T VW, Renton wetland, o�zSpringbrook Creek. a , In fact, if the dike along Springbrook Creek had been removed several years ago, runoff from the Parcel 14 including the wetlands would have drained into the ditch around the west and north boundary of the site, into the Boeing wetland, and ultimately into the City of �N Renton wetland; wetlands would not likely have formed on Parcel 14 under this situation. �o l9�"�� Even if the berm was removed in 1994 the water from the site (including the wet areas) DO 5 would still drain into the ditch resulting in naturally drained wetlands and potential ' 6 conversion to upland. ° o Fourth, two of the three wetlands on Parcel 14 (wetlands J and L) are isolated v� � F h depressions 1 separated from Wetland M, the Boeing wetland, the City of Renton wetland, and Springbrook Creek by large upland areas. The isolated nature and separation of wetlands in Block 8, Lot 3 from Springbrook Creek was the: rationale used by the Corps in determining that the wetlands on Lot 3 qualified for a. Nationwide 26 permit. A similar i rationale should be applied to wetlands J and L. Mitigation Site 2, Block 8, Lots 1, 2, 3, and 4 Mitigation Banking Site 2 is 13.93 acres and consists of wetlands on Lots 1, 2, and 4. The site consists primarily of herbaceous perennial grasses and forbs, annual fortis, and a fairly large young forested wetland community consisting primarily of cottonwoods and shrubs. Current and Existing Conditions The site was filled within the past 20 years and surface elevations range from 15 to 19 feet. With a few minor exceptions, the topography is relatively flat with small depressions formed by heavy equipment conducting grading work. The compactions from driving ont the site, rentonhurisdic.ren January 17, 1994 JAN-11-94 MON 9,3( FAKAME'I'KIX hAX NO. 2U6 689 66U6 F UU9 coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in depressional areas where wetlands have formed on top of the fill. These depressional areas developed a perched water table and eventually small lower quality wetlands formed on fill, The existing and current conditions are that the wetlands on Lots 1, 2, 4 have formed on top of compact fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek, The hydrology source for the existing wetlands on Mitigation Banking Site 2 is precipitation. Dl�a 0�-"There is no inlet or outlet between the wetlands and Springbrook Creek. Under current conditions, the dike prevents water from Springbrook Creek from entering the wetlands on (� Lots 1, 2, and 4, and prevents water from the wetlands from entering Springbrook Creek. The MFR prepared for mitigation banking site 2 indicates that the man made levee can not be considered in establishing adjacency (i.e., The Corps determine whether the wetlands would have formed or occur on the site in the absence of the levee). However, the Corps must also look at current conditions. The levee has been in place since the 1950's and is presence is a historic and current condition; it needs to be considered in determining the jurisdictional status. Adjacent? The Corps considers the wetlands that comprise Mitigation Banking Site 2 (Lots 1, 2, and 4) to be adjacent because they are contiguous with Springbrook Creek. There are issues and inconsistencies that require discussion before a final jurisdictional determination is made. First, The current MFR prepared for mitigation banking site 2 indicates that the man made levee can not be considered in establishing adjacency (Le., The Corps determines whether the wetlands would have formed, or would occur on the site in the absence of the levee). The elevation of the wetlands on Lots 1, 2, and 4 are at least 7 to 10 feet higher than the elevation of Springbrook Creek (using an elevation of about 8 feet based on average annual flow), and 1.5 to Afeet higher than a high Springbrook Creek flow (using a high flow elevation of,lkl0 &6 ased on a 100-year storm event) (East Side Green River-Watershed �_ o Plan). Thus, even if the dike were removed a consistent. hydrologic connection between the wetlands on Lots 1, 2, and 4 and Springbrook Creek would require the water,4eyation in W AS the creek between 34th Street and Oaksdale Avenue to be between/D<1 and,16.6Table 6S� _._ 4. Summary of Peak Flows and Water Surface Elevations, Current Land use Conditions -- f FEQ Hydraulic Analysis, East Side Green River Watershed Plan), In fact, based on data in the East Side Green River Watershed Plan, the only time the creek would reach these renton/jurisdic.ren January 17, 1994 JAN-17-94 MON 9:37 PARAMETRIX FAX N0, 206 889 8808 P. 07/09 elevations is during a 100-year storm event, This means that there is no hydrologic relationship between Springbrook Creek and the wetlands on Lots 1, 2, and 4. In addition, it would take a storm event greater than the 100 year storm event to (1) establish a regular hydrologic connection between Springbrook Creek and the wetlands on Lots 1, 2, and 4 and; (2) result in potential ponding long enough to support hydrophytic vegetation during the growing season. We know that wetlands requires periodic inundation/ponding/saturation for a sufficient period of time during each growing season to support hydrophytic vegetation. A 100-year storm event is not the hydroperiod to rely on to support hydrophytic vegetation; the wetlands source of hydrology is precipitation. u Thus, if the berm had been removed several years ago, runoff from the site including the wetlands would have drained into the creek and wetlands would not likely have formed. 4 ! Even if the berm were removed in 1994 the water from the site (including the wet areas) could drain into the creek resulting in naturally drained wetlands and potential conversion to upland. Second, the recent MFR prepared on the mitigation banking sites did not include the MFR for Lot 4 (eastern half of Mitigation Banking Site 2) dated April 20, 1992 as part of their analysis on the jurisdictional status of the wetlands on mitigation banking site 2. The MFR issued in April, 1992 indicates that the wetlands are perched, isolated depressions, with no hydrologic connection to other waters of the U.S.. Thy site qualifies for a Nationwide 26 permit based on location and impact to less than one acre. The determination made in 1992 for Lot 4 is inconsistent with the recent determination made for all of Mitigation Banking Site 2. In the recent determination for the entire mitigation site, the Corps indicates that the wetlands on Lots 1 and 2 are continuous and extend to the banks of Springbrook Creek. The wetland delineation figures from the David Evans reports for Lots 1, 2, and 3, and Lot 4 indicate that the wetlands on Lot 4 and Lot 1 are separated from the creek by upland / areas (25 to 75 feet and 50 to 200 feet, respectively). The determination on wetlands on Lot `r 4 made in 1992 indicates the wetlands are not adjacent to Springbrook Creek; it is difficult to understand how the Corps determined that the wetlands on Lot 1 were adjacent when the upland distance between the wetlands on Lot 1 and Springbrook Creek are greater than the upland distances between the wetlands on Lot 4 and Springbrook Creek. There are no other differences between the wetlands on Lot 1 and :Lot 4 other than the differences in upland distances between the wetlands and Springbrook Creek. Lastly, the wetlands on Lot 2 are a continuation of t he wetland on Lot 4 (i.e., all one wetland). Wetlands on Lot 2 were also determined to be adjacent by the Corps in their MFR on mitigation banking site 2. How can the wetlands on Lot 4 be isolated and qualify for a Nationwide 26 when the wetlands on Lot 2 be adjacent when they are one wetland system? The Corps should reevaluate their determination made on the entire mitigation site in light of the fact that the wetlands on Lot 2 are part of the same wetlands on Lot 4, which renton1jurisdic.ren January 17, 1994 JAN-17-94 MON 9:38 PARAMETRIX FAX NO, 206 889 8808 P, 08/09 were determined to be isolated and not adjacent to Springbrook Creek. The Corps could decide to revoke the isolated determination made on Lot 4 as part of their reevaluation, rentonljurisdic.ren January IZ 1994 JAN-17-94 MON 9:39 PARAMETRIX FAX NO. 206 889 8808 P. 09/09 o a. I L I No gq am i - 2 � 1 2r=AV Purl i ... _ ................. - p i N to v ............... ..... �.. O Q v, ;. .. LLI i is ... .... Iy.57eww ar9s>tr .. .._... ..................in o uj C� l0 IO R)to ! CV m �Oc� COC4 -5 m CO a --. :• --:. z Z u O 0 0 1n � b iu ci C-:In ILi n < r-z v AI ......... G 3 W y� cL ..._.�..... Ex.- ............. _ . co i r�i7�9y i is d7 wxetqj5 c,r +A-e, �4,, � 51�5 i i ! I ' i i Many areas in the Valley that were filled over the past 20 years were developed; however, some filled areas were not, and depressional areas on the undeveloped filled sites collected rainwater. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Sites 1 and 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. Mitigation Site 1, #14 Parcel Mitigation Banking Site 1 is 30.97 acres and consists of 18.78 acres of wetland (Figure 1). The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, upland shrub communities, and a fairly large forested wetland community consisting primarily of cottonwoods and shrubs. Current and Existing Conditions At least one-third of Parcel 14 has either been cleared, or cleared and filled, with gravel and sand from 12 to 48 inches in depth (David Evans and Associates 1991). A 4-foot-high mound of fill material covers approximately 1 acre of the site. Currently the soils on-site are fill material; historically the site was characterized by three soil types: Puyallup fine sandy loam (non-hydric), Woodinville silt loam (hydric), and Puget silty clay loam (hydric). The non-hydric soil type is the dominant underlying soil type and occurs largely in the central portion of the site and continues to the north and south of the site. The source of hydrology for the wetlands on Parcel 14 is precipitation. The wetlands occur in depressional areas that hold precipitation and leave the site by evapotranspiration and infiltration processes. The existing and current conditions are that the wetlands on Parcel 14 have formed on top of compact fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. The MFR prepared for Mitigation Banking Sites 1 and 2 indicates that the man made levee can not be considered in establishing adjacency (i.e., The Corps determine whether the wetlands would have formed or occur on the site in the absence of the levee). However, the Corps must also look at current conditions. The levee has been in place since the 1950's and is presence is a historic and current condition; it needs to be considered in determining the jurisdictional status. renton/jurisdic.ren January 17, 1994 Adjacent? The Corps considers the wetlands that comprise Mitigation Banking Site 1 (Parcel 14) to be adjacent because they are continuous with a large wetland parcel owned by the City of Renton (wetland W-12), immediately adjacent to Springbrook Creek (see Figure 1). The Corps MFR indicates that wetlands on Parcel 14 are adjacent because (1) they are contiguous with wetlands to the north and east (the Boeing and City of Renton wetlands); (2) the City of Renton wetlands extend over to Springbrook Creek; and (3) the City of Renton wetlands periodically experience flooding from Springbrook Creek, which in turn may back water into the ditch along the northern boundary of Parcel 14. The issues associated with the adjacency determination are outlined below. First, the MFR issued for Parcel 14 indicated that a jurisdictional determination for the site would require further analysis and that the man-made drainage ditch along the western edge of the site appears to be connected to an open water wetland (the City of Renton wetland) and from there to Springbrook Creek. The City found no direct connection between the City of Renton wetland and Springbrook Creek (based on survey in August 1993). A drainage ditch occurs along the western boundary of the site and carries water from offsite, south of Parcel 14, around the western and northern boundary of Parcel 14. The water then drains into the Boeing wetland (W-13), north of the potential P-channel easement and Parcel 14 (see Figure 1). Once in wetland W-13, the water drains into a 48 inch culvert located under the extension of Oaksdale Avenue and drains into the City of Renton wetland (W-12). The City of Renton wetland (W-12) consists of two-cells separated by a road. The elevation of the City of Renton wetland is 11 feet; the elevation of the road is 13 to 14 feet. The west cell has a ditch/culvert connection to the Boeing wetland (W-13). There is no culvert or ditch connection between the east and west cell of the City of Renton wetland', and hence no connection to Springbrook Creek. Once water enters into the west cell of the City of Renton wetland, it is retained within the wetland and leaves the site through evapotranspiration and infiltration. No direct outlet was found between the east cell of the City of Renton wetland to Springbrook Creek. However, a ditch connects to a portion of the berm along Springbrook Creek- water could enter into the ditch from Springbrook Creek during a high flow event (11 to 14 feet based on 100-year event). Flood waters would need to increase the elevation of the east cell above 13 feet before it overtops the road and enters the west cell. 'The City of Renton Public Works maintenance crew conducted a site visit in September 1993 to determine if a culvert was present between the west and east cell of W-12. Using a metal detector and various probes no culvert or other type of connection between the two cells was found. renton/jurisdic.ren January 17, 1994 This information indicates that under current conditions there is no direct regularly reoccurring surface connection between the east cell of the City of Renton wetland and Springbrook Creek, and no connection between the east and west cells. How can the wetlands on Parcel 14 be continuous with Springbrook Creek if there is no regular connection (other then during a 100-year event) between Springbrook Creek and the east cell of W-12, and the elevation of the wetlands on Parcel 14 are 3 to 4 feet higher than wetland W-12? Second, the drainage ditch along the western boundary of the site that carries water from offsite, south of Parcel 14, around the western and northern boundary of Parcel 14. The water into the Boeing wetland (W-13), north of the potential P-channel easement and Parcel 14 is lower in elevation than the elevation of the wetlands on Parcel 14 by an estimated 3 to 4 feet. The ditch does not currently provide a source of hydrology to the wetlands on Parcel 14. Although water entering the drainage ditch drains into the Boeing wetland (W- 13) and ultimately into the west cell of the City of Renton wetland, there is no evidence that the surface elevation of water in the ditch crests over the top of the ditch into the wetlands on Parcel 14. Without evidence of overtopping it is difficult to determine that there is a hydrologic connection between the wetlands on Parcel 14 and the City of Renton wetland. Thus, there is no inlet for water to drain from the west cell of the City of Renton wetland into the Boeing wetland, and into wetlands on Parcel 14 under current and existing conditions. Under current conditions, the lower elevation in the ditch and the lack of a direct connection between the City of Renton wetland and Springbrook Creek prevents water from Springbrook Creek from entering the City of Renton wetland, and hence the wetlands on Parcel 14. Third, as a result of filling activities, the elevation of the wetlands on parcel 14 are estimated to be at least 8 to 10 feet higher than the elevation of Springbrook Creek (using an elevation of about 8 feet based on average annual flow), and 2 to 4 feet higher than a high Springbrook Creek flow (using a high flow elevation of 11 to 14 at SW 27th Street based on a 100-year storm event) (East Side Green River Watershed Plan). In addition, the elevation of the wetlands on parcel 14 are estimated to be 3 to 4 feet higher than the City of Renton wetland (W-11 and W-12). The MFR indicates that the City of Renton wetland contained standing water and is likely flooded by high waters overbanking Springbrook Creek on a regular and periodic basis. The information available on elevations of the wetlands and the water level in Springbrook during a normal event and high flow event show that water from Springbrook Creek can only get into the east cell of W-12 during a 100-year event-this can not be considered a regular or periodic basis. The results of the FEQ simulations in the East Side Green River Watershed Plan indicate that wetlands W-11 and W-12 provide substantial storage volume and reduce peak flow during a 100-year storm event. For example, as the culvert crossing renton/jurisdic.ren January 17, 1994 at Southwest 27th Street restricts flow, the water surface elevation in Springbrook Creek rises and spills out into wetlands W-11 and W-12. As Springbrook Creek continues to rise these wetlands continue to fill and store a combined volume of approximately 240-acre feet for the 100-year flood. Thus, a 100-year storm event is required before there is a temporary hydrologic connection between Springbrook Creek and the City of Renton wetland. Even if the dike along Springbrook Creek were removed, a 100-year event would still be required before Springbrook Creek would flow over into the east cell of the City of Renton wetland. In addition, even if an assumption could be made that a 100-year event results in flooding of the east and west cell of the City of Renton wetland, the storage capacity of the City of Renton wetland would have to become saturated before water backed up into the Boeing wetland (W-13), the ditch around Parcel 14, and ultimately into Parcel 14. If it requires a 100-year event or greater for this to occur, it is reasonable to suggest that there is not a direct or continuous connection between the wetlands on Parcel 14, the Boeing or City of Renton wetland, or Springbrook Creek. In fact, if the dike along Springbrook Creek had been removed several years ago, runoff from the Parcel 14 including the wetlands would have drained into the ditch around the west and north boundary of the site, into the Boeing wetland, and ultimately into the City of Renton wetland; wetlands would not likely have formed on Parcel 14 under this situation. Even if the berm was removed in 1994 the water from the site (including the wet areas) would still drain into the ditch resulting in naturally drained wetlands and potential conversion to upland. Fourth, two of the three wetlands on Parcel 14 (wetlands J and L) are isolated depressions separated from Wetland M, the Boeing wetland, the City of Renton wetland, and Springbrook Creek by large upland areas. The isolated nature and separation of wetlands in Block 8, Lot 3 from Springbrook Creek was the rationale used by the Corps in determining that the wetlands on Lot 3 qualified for a Nationwide 26 permit. A similar rationale should be applied to wetlands J and L. Mitigation Site 2, Block 8, Lots 1, 2, 3, and 4 Mitigation Banking Site 2 is 13.93 acres and consists of wetlands on Lots 1, 2, and 4. The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, and a fairly large young forested wetland community consisting primarily of cottonwoods and shrubs. Current and Existing Conditions The site was filled within the past 20 years and surface elevations range from 15 to 19 feet. With a few minor exceptions, the topography is relatively flat with small depressions formed by heavy equipment conducting grading work. The compactions from driving ont the site, renton/jurisdic.ren January 17, 1994 coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in depressional areas where wetlands have formed on top of the fill. These depressional areas developed a perched water table and eventually small lower quality wetlands formed on fill. The existing and current conditions are that the wetlands on Lots 1, 2, 4 have formed on top of compact fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. The hydrology source for the existing wetlands on Mitigation Banking Site 2 is precipitation. There is no inlet or outlet between the wetlands and Springbrook Creek. Under current conditions, the dike prevents water from Springbrook Creek from entering the wetlands on Lots 1, 2, and 4, and prevents water from the wetlands from entering Springbrook Creek. The MFR prepared for mitigation banking site 2 indicates that the man made levee can not be considered in establishing adjacency (i.e., The Corps determine whether the wetlands would have formed or occur on the site in the absence of the levee). However, the Corps must also look at current conditions. The levee has been in place since the 1950's and is presence is a historic and current condition; it needs to be considered in determining the jurisdictional status. Adjacent? The Corps considers the wetlands that comprise Mitigation Banking Site 2 (Lots 1, 2, and 4) to be adjacent because they are contiguous with Springbrook Creek. There are issues and inconsistencies that require discussion before a final jurisdictional determination is made. First, The current MFR prepared for mitigation banking site 2 indicates that the man made levee can not be considered in establishing adjacency (i.e., The Corps determines whether the wetlands would have formed, or would occur on the site in the absence of the levee). The elevation of the wetlands on Lots 1, 2, and 4 are at least 7 to 10 feet higher than the elevation of Springbrook Creek (using an elevation of about 8 feet based on average annual flow), and 1.5 to 2 feet higher than a high Springbrook Creek flow (using a high flow elevation of 13 to 16 based on a 100-year storm event) (East Side Green River Watershed Plan). Thus, even if the dike were removed a consistent hydrologic connection between the wetlands on Lots 1, 2, and 4 and Springbrook Creek would require the water elevation in the creek between 34th Street and Oaksdale Avenue to be between 12.2 and 16.6 (Table 4. Summary of Peak Flows and Water Surface Elevations, Current Land use Conditions -- FEQ Hydraulic Analysis, East Side Green River Watershed Plan). In fact, based on data in the East Side Green River Watershed Plan, the only time the creek would reach these renton/jurisdic.ren January 17, 1994 elevations is during a 100-year storm event. This means that there is no hydrologic relationship between Springbrook Creek and the wetlands on Lots 1, 2, and 4. In addition, it would take a storm event greater than the 100 year storm event to (1) establish a regular hydrologic connection between Springbrook Creek and the wetlands on Lots 1, 2, and 4 and; (2) result in potential ponding long enough to support hydrophytic vegetation during the growing season. We know that wetlands requires periodic inundation/ponding/saturation for a sufficient period of time during each growing season to support hydrophytic vegetation. A 100-year storm event is not the hydroperiod to rely on to support hydrophytic vegetation; the wetlands source of hydrology is precipitation. Thus, if the berm had been removed several years ago, runoff from the site including the wetlands would have drained into the creek and wetlands would not likely have formed. Even if the berm were removed in 1994 the water from the site (including the wet areas) could drain into the creek resulting in naturally drained wetlands and potential conversion to upland. Second, the recent MFR prepared on the mitigation banking sites did not include the MFR for Lot 4 (eastern half of Mitigation Banking Site 2) dated April 20, 1992 as part of their analysis on the jurisdictional status of the wetlands on mitigation banking site 2. The MFR issued in April, 1992 indicates that the wetlands are perched, isolated depressions, with no hydrologic connection to other waters of the U.S.. The site qualifies for a Nationwide 26 permit based on location and impact to less than one acre. The determination made in 1992 for Lot 4 is inconsistent with the recent determination made for all of Mitigation Banking Site 2. In the recent determination for the entire mitigation site, the Corps indicates that the wetlands on Lots 1 and 2 are continuous and extend to the banks of Springbrook Creek. The wetland delineation figures from the David Evans reports for Lots 1, 2, and 3, and Lot 4 indicate that the wetlands on Lot 4 and Lot 1 are separated from the creek by upland areas (25 to 75 feet and 50 to 200 feet, respectively). The determination on wetlands on Lot 4 made in 1992 indicates the wetlands are not adjacent to Springbrook Creek; it is difficult to understand how the Corps determined that the wetlands on Lot 1 were adjacent when the upland distance between the wetlands on Lot 1 and Springbrook Creek are greater than the upland distances between the wetlands on Lot 4 and Springbrook Creek. There are no other differences between the wetlands on Lot 1 and Lot 4 other than the differences in upland distances between the wetlands and Springbrook Creek. Lastly, the wetlands on Lot 2 are a continuation of the wetland on Lot 4 (i.e., all one wetland). Wetlands on Lot 2 were also determined to be adjacent by the Corps in their MFR on mitigation banking site 2. How can the wetlands on Lot 4 be isolated and qualify for a Nationwide 26 when the wetlands on Lot 2 be adjacent when they are one wetland system? The Corps should reevaluate their determination made on the entire mitigation site in light of the fact that the wetlands on Lot 2 are part of the same wetlands on Lot 4, which renton/jurisdic.ren January 17, 1994 were determined to be isolated and not adjacent to Springbrook Creek. The Corps could decide to revoke the isolated determination made on Lot 4 as part of their reevaluation. renton/jurisdic.ren January 17, 1994 o a. peoy�Ile�zsea � a I q �/� LLI < t:r- a cl i 7aa � V 77• � C7 I� U. QD _ n n •� :..:.. ::........... N N i ... :_ .. :t:... I i 07 Z EN . = ...... ... .:_�" �. .� ........ ................... Z . :� _ _ : : LL, �' °L '• w .:.: : . L... .. : •:•. 1 Yy `-• 111 t`Cz Lo to to 'tcn t0 � 3 o _ _ � L• A!.. d V � � Cl ..... ..._.. Z Z v ^O ^00 4O 3 O LLI3 LL, u�m r- o u to 0.3 C•(� (fl p - C) t-ILA In,6 -I- r-.: F- "-w.LL ... v ro _ •� - ) m N In CO Cfl� � � J ..ate m m.�".. v ------------ C3 .•.� .. - •--• - --- V . T d. -+ .... ... ..----- _....•�. _..•.......... .. F� Wv lb .Jf gCh Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd. N.E. Kirkland,WA 98033-7350 �.al 206-822-8880•Fax:206-889-8808 OF Scott Woodbury E g neermg �Epc. December 15, 1993 City of Renton 55-1779-07 200 Mill Avenue S. Renton, Washington 98055 Dear Scott: Enclosed is an invoice for services rendered through November 30, 1993. Work performed by Talasaea Associates from August through November is also included in this invoice. Task 1A - Project Management Work performed by Tracey McKenzie included discussion with the City about having a meeting with agencies and the public in light of the City employee strike, and coordination with the project team. Kim Naughten and Courtney Templeton are administrative staff and assisted with project invoicing and accounting activities. Task 1B - Regulatory and Resource Agency Coordination Work performed by Tracey McKenzie included coordination with the City and providing preliminary information for the City to use in discussions with the Corps regarding the adjacency determination for the wetlands on the mitigation banking sites. Work performed by Talasaea included one public meeting (in lieu of one meeting with the agencies) and discussion of the Corps preliminary jurisdictional determination with Tracey McKen-zie Task 1D - Conditions Assessment and Field Work Michael Johnstone, Parametrix CADD operator, produced figures to include in the mitigation plan. Tracey McKenzie prepared and refined the conditions assessment and worked with Mr. Johnstone to produce CADD figures. Work performed by Talasaea included field time in August, discussion of the conditions assessment with Tracey McKenzie, and a review of draft conditions assessment. �0� Printed on Recycled Paper 1 4 Scott Woodbury City of Renton December 15, 1993 Page 2 Task 1E - Mitigation Plan Preparation Jim Burton, a member of Parametrix graphics department, prepared graphics for inclusion in the mitigation plan. Michael Ehelebe of Parametrix' document production department compiled and copied Chapters 1 through 6 of the draft mitigation plan. Work performed by Shanon Harris included incorporating changes into the text, producing t aides, coordination with the graphics and document production departments, word processing, and general QA/QC of the document. Catherine Smith, as Parametrix' technical editor, provided editorial services for Chapters 1 through 6. Kim Naughten, a member of Parametrix' support staff, performed accounting activities. Work performed by Tracey McKenzie on this task included proofreading Chapters 1 through 6 and drafting subsequent chapters of the mitigation plan. Work performed by Talasaea included reviewing Chapters 1 through 6 of the mitigation plan and preparing preliminary site plans for the mitigation sites. If you have any questions or require more information, please call me at (206) 822-8880. Sincerely, PARAMETRIX, INC. �U" Tracey P. McKenzie enclosure Parametrix, Inc. 0 To: Scott Woodbury Date: December 14,1993 City of Renton Project No: 55-1779-07 200 Mill Avenue South Renton, WA 98055 From: Washington Oregon Hawaii ❑ 5700 Kitsap Way ❑ 1231 Fryar Avenue ❑ 7820 N.E.Holman ❑ 1164 Bishop Street Suite 202 P.O. Box 460 Suite B-6 Suite 1600 Bremerton,WA 98312-2234 Sumner,WA 98390-1516 Portland,OR 97218-2859 Honolulu, HI 96813-2832 206-377-0014 206-863-5128 503-256-5444 808-524-0594 206-383-1835 206-838-9810 206-694-5020 Fax:808-523-2995 Fax:206-479-5961 Fax:206-863-0946 Fax:503-256-4221 X5808 Lake Washington Blvd. N.E. L7 25 N.Wenatchee Avenue Texas Kirkland,WA 98033-7350 Suite 207 10540 Rockley Road 206-822-8880 Wenatchee,WA 98801-2236 Suite 300 Fax:206-889-8808 509-664-3290 Houston,TX 77099 Fax:509-663-8816 713-530-1920 Fax:713-530-6744 We are transmitting the following materials: One copy each of Newton Creek Wetland Conservation Plan and West Eugene Wetlands Plan. i x G 1993 Comments: CITY OF RENTCN Eiligineering Dept. These are: Per your Request X For your Information For your Review and Approval For your Files For your Action Sincerely, cc: 1 Tracey McKenzie Parametrix, Inc. To-., Date: Project No: From: Washington Oregon Hawaii 5700 Kitsap Way El 1231 Fryar Avenue 7820 N.E.Holman 1164 Bishop Street Suite 202 P.O.Box 460 Suite B-6 Suite 1600 Bremerton,WA 98312-2234 Sumner,WA 98390-1516 Portland,OR 97218-2859 Honolulu,HI 96813-2832 206-377-0014 206-863-5128 503-256-5444 808-524-0594 206-383-1835 206'838-9810 206-694-5020 Fax:808-523-2995 Fax:206-479-5961 Fax:206-863-0946 Fax:503-256-4221 808 Lake Washington Blvd.N.E. ❑ 25 N.Wenatchee Avenue Kirkland,WA 98033-7350 Suite 207 206-822-8880 Wenatchee,WA 98801-2236 Fax:206-889-8808 509-664-3290 Fax:509-663-8816 We are transmitting the following materials: C � 4) Comments: These are: ❑ Per your Request For your Information ❑ For your Review and Approval ❑ For your Files ❑ For your Action Sincerely, cc: PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 !� y a UTILITY SYSTEMS DIVISION - 235-2631 NT TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: JOB NO.: RE: ATTN: GENTLEMEN: WE ARE SENDING YOU ❑ ATTACHED o UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: ❑ SHOP DRAWINGS ❑ PRINTS ❑ REPRODUCIBLE PLANS ❑ SPECIFICATIONS ❑ COPY OF LETTER ❑ COPIES DATE NUMBER DESCRIPTION AND REMARKS THESE ARE TRANSMITTED AS CHECKED BELOW: ❑ FOR APPROVAL ❑ APPROVED AS SUBMITTED o RESUBMIT COPIES FOR APPROVAL ❑ FOR YOUR USE o APPROVED AS NOTED ❑ SUBMIT COPIES FOR DISTRIBUTION ❑ AS REQUESTED o RETURNED FOR CORRECTIONS o RETURN CORRECTED PRINTS o FOR REVIEW AND COMMENT ❑ o PRINTS RETURNED AFTER LOAN TO US COPIES TO: SIGNED TITLE IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE "t3 s,Y aArlr-A, Ti p 61 u, S,H),g . D s�ca T�Fw. RO"W" RsLrv, UN �6r�T/tiuiNG SEou6N�.!/�G. 6�Nn tiG�n-+fNr �-,k-��,�2t,4 . GoP�s ��S N�+��_ �/u o a gc�c.� ��o•�..� nMvk1LTf0 / /cloUCCA41 )iGO .ova . T/Lf,j o r-W. T//UJr�(� . c��c.p OSE 'MA r1c E.v�6N+J— /°1f% ril l'-4p,(T . ("tl ND'( /�,b f t� p� Tt R•�rk SuFf r u r Garr/gE.-�F�r /ZATJ o of GrCwf'6r USt ,�.�%�A►�Ci,4,.A- r Folk M'tr)GA--TTW /k�!O 6c /6/,y\e 2s,'d- Lh s1.Ik 5UFPO VS GE^-LnAL- F Attv rNA" t'o p l c /*j rv+. rJ(i/Z -v6 S 7ol /'lug S jvP�rr�, _ JrXT ar-r -s,71L. o6L1/v&47-i(ja /1' 07 _614AJn4-4-- 1'�'L m i So = 0-�-3-8 )#j Ix nv/z TRA4t- oN� vw C6s� Sim � S� )c 3 o it c h 1r#b w)r)T# 0,(- S'/bcw^ctc �/=�v�� Ir�,R S>7-i 2- Al,jr S Uf 0AUP044 AL406 s/-r& 1 •kKATIUri 'To f/L . Ctreg. C c,LOT L s/76 PAs PvPp4Aj o lcA--� , NW,o .v�- Tim 70 KV7 ad w/ su PfALAW5 . IVkr 3T6-P A o,, ,o Fn fti. - wl Ceps ors A P JA a,,)cy ,A,,v W;- Pt,�9xts -73 �9 A ZAl YO DiA � TUPo .. t s PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT rrti\ `�Y O� MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 0 UTILITY SYSTEMS DIVISION - 235-2631 `�l NT TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: JOB NO. : RE: ATTN: GENTLEMEN: WE ARE SENDING YOU o ATTACHED ❑ UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: o SHOP DRAWINGS o PRINTS ❑ REPRODUCIBLE PLANS ❑ SPECIFICATIONS ❑ COPY OF LETTER o COPIES DATE NUMBER DESCRIPTION AND REMARKS THESE ARE TRANSMITTED AS CHECKED BELOW: o FOR APPROVAL ❑ APPROVED AS SUBMITTED ❑ RESUBMIT COPIES FOR APPROVAL ❑ FOR YOUR USE ❑ APPROVED AS NOTED ❑ SUBMIT COPIES FOR DISTRIBUTION o AS REQUESTED ❑ RETURNED FOR CORRECTIONS ❑ RETURN CORRECTED PRINTS ❑ FOR REVIEW AND COMMENT ❑ o PRINTS RETURNED AFTER LOAN TO US COPIES TO: SIGNED TITLE IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE f Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd.N.E. Kirkland,WA 98033-7350 206-822-8880•Fax:206-889-8808 to TIXII O Scott Woodbury C� 3 1993 December 1, 1993 City of Renton `}` ,,,-�p``1 55-1779-07 200 Mill Avenue S. ,.fit pF '`� ,pt• Renton, Washington 98055 Dear Scott: Enclosed is an invoice for services rendered through October 31, 1993. Work performed during this period included: Task IA - Project Management Technical support to assist and coordinate with the City as well as attending one meeting at the City office to discuss the preliminary draft chapters of the mitigation plan. Task 1B - Regulatory and Resource Agency Coordination Work for this task involved identifying agencies, agency staff, and agency phone numbers for the City, and assisting the City with coordinating with the U.S. Army Corps of Engineers. Also included is attendance at one public meeting (in lieu of one meeting with agencies) which was included in the original scope and schedule. Task 1C - Mitigation Goals and Objectives Work for this task involved refinement of goals, objectives, and policy issues. Time for a meeting with the City to discuss the initial araft chapters of the mitigation plan was also charged to this task by Kittie Ford. Task 1D - Conditions Assessment and Field Work Work performed for this task included development and refinement of AutoCAD figures and maps and finalization of drafts of chapters on the conditions assessment and field work. ` o Printed on Recycled Paper J Scott Woodbury City of Renton December 1, 1993 Page 2 Task lE - Mitigation Plan Preparation Work performed for this task included coordination with the City and consulting team on development of the conceptual and final site plans, one 6-hour meeting with the consultant team and a Parametrix hydraulic engineer to discuss options for establishing hydrology to the mitigation banking sites, and drafting of additional sections of the mitigation. If you have any questions or require additional information, please call me at (206) 822-8880. Sincerely, PARAMETRIX, INC. Tracey P. McKenzie enclosure t THE CITY OF RENTON DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS FOURTH FLOOR 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055-2189 FAX: 235-2541 To: Tracey McKenzie Company: Parametrix, Inc Phone: 206-828-4204 3459 Fax: 206-889-8808 From: Scott Woodbury Company: City of Renton Phone: 277-5547 Fax: 235-2541 Date: 11/29/93 Pages including this cover page: 7 Comments: Attached are Ron Straka's and my comments regarding your November 8, 1993 memorandum of information for the meeting with the Corps. Please revise to address the comments and restructure the memo so that it could be submitted to the Corps in the future if needed. Attach any exhibits that will help support the conclusions. It is important that this be a team effort by Parametrix and Talasaea and be noted so in a cover sheet or signatory page. Please let me know when you would be able to complete the revision so that I can reschedule the meeting with the Corps which we had to cancel because of the City union strike. Thank you for your assistance. V- 6-y� MUN 1 U:4b NAKAML I K I X HX NU. CUb 68y 86U8 P- 01/04 MEMORANDUM to: Scott Woodbury - City of Renton November 8, 1993 from: Tracey McKenzie - Parametrix, Inc. re: Information for Meeting with U.S. Army Corps of Engineers Enclosed is information that may be helpful to you in your discussions with the Corps on the jurisdictional determination of wetlands on the mitigation banking sites. Please call me at (206) 822-8880 if you have any questions or require additional information, FAX TRANSMITTAL. 14 To S cc;1 t ad From TP M Cato 1� .� co. Co. PARAMETRIX, INC. Dept. Phone (206)822.6880 Fax a 2 3� - 4 i Fax X (206) 889-8808 COMMENTS: NOV- 6-93 MON 10; 46 NAKAME'N 1 X FAX NO, 206 669 6606 N, 02/04 to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 2 Many areas in the Valley that were filled over the past 20 years were developed; however, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Sites 1 and 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. Without having the benefit of reading the Corps internal memorandum indicating the criteria and rationale used to make the jurisdictional determination, it is my understanding that the Corps has determined that wetlands on Mitigation Banking Site 1 are adjacent because they are contiguous with wetlands to the north and east (the City of Renton wetlands), the City of Renton wetlands extend over to Springbrook Creek, and the City of Renton wetlands periodically experience flooding from Springbrook Creek, which in turn may back water into the wetlands on Mitigation Banking Site 1, At least one-third of Mitigation Banking Site 1 has Either been cleared, or cleared and filled, with gravel and sand from 12 to 48 inches in depth (David Evans and Associates 1991). A 4-foot-high mound of fill material covers approximately 1 acre of the site. In addition to the fill material, the site is also characterized by three soil types: Puyallup fine sandy loam (non-hydric), Woodinville silt loam (hydric), and Puget silty clay loam (hydric). The non-hydric soil type is the dominant soil type and occurs largely in the central portion of the site and continues to the north and south of the site. As a result of filling activities over the past 20 years the elevation of the wetland areas are estimated to be 2 to 3 feet higher than the City of Renton wetlands and at least 4 to 5 feet higher than Springbrook Creek. The primary source of hydrology for the existing wetlands on Mitigation Banking Site 1 is precipitation. These wetlands are in depressional areas that hold precipitation prior to evapotranspiration and infiltration, A potential secondary source of hydrology for the wetlands on Mitigation Banking Site 1 is the drainage ditch that occurs along the western and northern boundary of the site. Although the elevations of the wetlands and uplands appear to be considerably higher (at least 3 to 4 feet) than this ditch, high flows may overflow the banks of the ditch and enter into the large: forested scrub-shrub and emergent wetland. However, the volume, flow rate, and water quality in this ditch system are not known, A relict tributary to Springbrook Creek, once evident within the central portion of the site, has been filled over the years. Surface water is presently diverted away from the relict tributary and flows through the north-south drainage ditch located just inside the western 4;�V- b-yJ MUN 1U;4t thxhnt1K1X hAX NU, ?Ub bd5 86U3 t', U3/U4 40( to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 3 boundary of the site, enters into a east-west drainage ditch, then flows east through a culvert under Metro's gravity sewer system and into the City of Renton Wetlands. Once water enters into the City of Renton wetlands, it is retained vzthin the wetland and leaves the site through evapotranspiration and infiltration. There is no direct outlet (i.e., culvert or day lighted stream or ditch) from the City of Renton wetlands to Springbrook Creek indicating that under current conditions there is no surface connection between the wetlands on Mitigation Banking Site 1 and Springbrook Creek, Mitigation Banking Site 2 is 13.93 acres. The site consists primarily of herbaceous perennial r grasses and forbs, annual £orbs, and a fairly large young forested wetland community consisting primarily of cottonwoods and shrubs. The site was filled within the past 20 years, \` and with a few minor exceptions, the topography is relatively flat with small depressions formed by heavy equipment conducting grading work. Surface elevations range from 15 to P 19 feet. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Site 2 have formed on top of fill, are isolated depressional areas, and , have developed as pans that are not connected by groundwater or surface water to ,fit Springbrook Creek. `l The soils on the site are mapped as Woodinville silt loam, a hydric soil (Snyder et al. 1973). $ However, the majority of the site consists of fill material. The site has been driven on and the compactions, coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in the areas where wetlands have formed on top of the fill, The hydrology source for the existing wetlands on Mitigation Banking Site 2 is precipitation. Wetlands on this site lack an obvious inlet or outlet. The Corps considers these wetlands to be adjacent because they are contiguous with Springbrook Creek, However, the elevation of the wetlands are at least 6 to 7 feet higher than the elevation of Springbrook Creek at low flow (surface elevation of 10 feet). During a 1.00-year storm event under current conditions water flows at about 850 cfs and the water surface elevation of Springbrook Creek near Oaksdale Avenue would be about 16.4 feet, This means that if the dike were � h removed water could enter into the wetland at the northeast corner of the site (at elevation of about 16 feet) during a 100-year storm event. It would take a storm event greater than the 100 year storm event to flood all of the existing wetlands with the dike removed. Even if water did get into the wetlands on Mitigation Banking Site 2, it is important to know the V duration of inundation or soil saturation. The City should discuss the opportunity of w monitoring the duration and soil saturation in the wetlands to determine if ponding occurs for a long duration [i.e,, at least 2 weeks in the growing season (March 1 through October 31)], or if the soils are flooded for a long duration (i.e, at least 2 weeks during the growing I1VY U UV 11V11 IV"TV 1 11I11111L 1111f1 LVU UUQ UVUU ULi/ Ulf to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 4 season) with the Corps. If ponding or flooding of the v ietland areas does not occur for long or very long duration (i.e, 2 weeks or more during 1he growing season) the Corps may reconsider their jurisdictional determination for the wetlands on Mitigation Banking Site 2, They City could also discuss the possibility of monitoring the duration of ponding and flooding of the wetlands on Mitigation Site 1 to determine if the Corps would reconsider their jurisdictional determination on these wetlands, However, I am less confident that the Corps will reconsider their jurisdictional determination of the wetlands on Mitigation Banking Site 1 because at least one wetland (Wetland M) occurs in a more or less continuous band with neighboring wetlands that extend over to the banks of Springbrook Creek. �• .Lc � .. �y l 1n L-a / '0 �v o OJ Hull iu-4J I"tiKt1I1CInIA h A*Nu, CUd 00d tOUO r. ul/A i MEMORANDUM to: Scott Woodbury - City of Renton November 8, 1993 from: Tracey McKenzie - Parametrix, Inc. re: Information for Meeting with U.S. Army Corps of Engineers Enclosed is information that may be helpful to you in your discussions with the Corps on the jurisdictional determination of wetlands on the mitigation banking sites. Please call me at(206) 822-8880 if you have any questions or require additional information, FAX TRANSMITTAL 71tpa ea To SCAR t From TP Mckv-, 6 co. co. PARAMETRIX, INC. Dept. Phone (206)822-8880 Fax 9 2 3 S - -D S 4 i Fax (206)889-8808 COMMENTS: iruv- 0-1J.) I IUN i U-4o rHKHfi>✓I K 11S F HX NU, LUb bby bbUb N, U2/U4 to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 2 rok s 11k u-' Co Ec c�Trt i fi Many areas in the Valley that were filled over the past 20 years were developed; however, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Sites 1 and 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. Without having the benefit of reading the Corps internal memorandum indicating the criteria and rationale used to make the jurisdictional determination, it is my understanding that the Corps has determined that wetlands on Mitigation Banking Site 1 are adjacent because they are contiguous with wetlands to the north and east (the City of Renton wetlands), the City of Renton wetlands extend over to Springbrook Creek, and the City of Renton wetlands periodically experience flooding frorn Springbrook Creek, which in turn may back water into the wetlands on Mitigation Banking Site 1, A%Ayt3,e Nvro -r,yE or7Z;4 ,MA At least one-third of Mitigation Banking Site 1 has either been cleared, or cleared and filled, with gravel and sand from 12 to 48 inches in depth (David Evans and Associates C's k kf 1991). A 4-foot-high mound of fill material covers approximately 1 acre of the site. In addition to the fill material, the site is also characterized by three soil types: Puyallup fine UP sandy loam (non-hydric), Woodinville silt loam(hydric), and Puget silty clay loam (hydric). Ov The non-hydric soil type is the dominant soil type and occurs largely in the central portion of the site and continues to the north and south of the site.As oresuls of filling6ac 'vities over the past 20 years the elevation of the wetland areas are estimafed to be Jr to feet higher than the City of Renton wetlands and at least 4 to F feet higher than Springbrook Creek. The primary source of hydrology for the existing wetlands on Mitigation Banking Site 1 is precipitation. These wetlands are in depressional areas that hold precipitation prior to evapotranspiration and infiltration, A potential secondary source of hydrology for the wetlands on Mitigation Banking Site 1 is the drainage ditch that occurs along the western and northern boundary of the site. Although the Eflevations of the wetlands and uplands ��^y appear to be considerably higher (at least 3 to T feet) than this ditch, high flows may overflow the banks of the ditch and enter into the large forested scrub-shrub and emergent wetland. However, the volume, flow rate, and water quality in this ditch system are not known, of 4-A)t UAF o9g145 A relict tributary to Springbrook Creek, once evident within the central portion of the site,,N 0,Tf4, ooEs has been filled over the years. Surface water is presently diverted away from the relict V,3r iNoxAne tributary and flows through the north-south drainage ditch located just inside the western ma's "�Jria U Q') 11VII i U-v 1 1 Mnl1L i 1�i n r HA 14U, CUD 000 o000 1'. UJ/U4 I to: Scott Woodbury - City of Renton pfi� from: Tracey McKenzie - Parametrix, Inc. �, tip rib November 8, 1993 �r UU4 a� 00t," Page 3 LA" �nrJ+ Tot Ewj F P'S�,�G�(�G wk^ � �S12G 2 gati S u,fir boundary of the site, enters into a east-west drainage ditch, then flows east through a culvert nay �° ass'under Metro's gravity sewer system and into the City of Renton Wetlands. Once water enters into the City of Renton wetlands, it is retained vzthin the wetland and leaves the site A, ff UN� through evapotranspiration and infiltration, There is no di t o eeutlet (i.e., cu veri or y No urrL4r lighted stream or ditch) from the City of Renton wetlands to Springbrook Creek indicating that under current conditions there is no surface connection between the wetlands on Mitigation Banking Site 1 and Springbrook Creek, Luy a.r /t$uv/ 57"-* k_1;"rb% TF- ot- U�V'i/LrOOf/ o PJ 7PtVs a✓ FPO& 2 r ? 54? Mitigation Banking Site 2 is 13.93 acres. The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, and a fairly large young forested wetland community consisting primarily of cottonwoods and shrubs. The site was filled within the past 20 years, and with a few minor exceptions, the topography is relatively flat with small depressions formed by heavy equipment conducting grading work. Surface elevations range from 15 to 19 feet. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Site 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. w�S The soils on the site are mapped as Woodinville silt loam, a hydric soil (Snyder et al. 1973). However, the majority of the site consists of fill material. The site has been driven on and the compactions, coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in the areas where wetlands have formed on top of the fill, �' The hydrol gy source for the e ' etlands on Mitigation Banking Site 2 is precipitation. Wetlands n this site lack inlet or outlet. The Corps considers these wetlands 0`5 P to be adi, cent because they are contiguous wit t pringbrook Creek. However, the elevation of the wetlands are at least 6 to 7 feet higher than the elevation of Springbrook Creek at low flow (surface elevation of 10 feet). During a 100-year storm event under current laws ^"T conditions water flows at about 850 cfs and the water surface elevation of Springbrook A l r .A..r Creek near Oaksdale Avenue would be about 16.4 feet, This means that if the dike were /4"0 Fho , removed water could enter into the wetland at the northeast corner of the site (at elevation o/11,11" By of about 16 feet) during a 100-year storm event. It would take a storm event greater than US4'"'� '`"'"r, `gym Kv,`� the 100 year storm event to flood all of the existing wetlands with the dike removed. Even pikE vo�s 1p if water did get into the wetlands on Mitigation Banking Site 2, it is important to know the "0s puts slrrt,A,o 9,0 duration of inundation or soil saturation. The City should discuss the opportunity of a� monitoring the duration and soil saturation in the wetlands to determine if ponding occurs for a long duration [i.e,, at least 2 weeks in the growing season (March 1 through October 31)], or if the soils are flooded for a long duration (Le, at least 2 weeks during the growing DU Tu SLGCar ir►�N)ra/t1rK G�vL,� Uu2 S u r.�,Av>r Fox arWA- ^coF D F1tk4 M 10 A-r)J+JS. Y to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 4 season) with the Corps. If ponding or flooding of the vietland areas does not occur for long or very long duration (i.e, 2 weeks or more during the growing season) the Corps may reconsider their jurisdictional determination for the wetlands on Mitigation Banking Site 2, They City could also discuss the possibility of monitoring the duration of ponding and flooding of the wetlands on Mitigation Site 1 to determine if the Corps would reconsider their jurisdictional determination on these wetlands. However, I am less confident that the Corps will reconsider their jurisdictional determination of the wetlands on Mitigation Banking Site 1 because at least one wetland (Wetland M) occurs in a more or less continuous band with neighboring wetlands that extend over to the banks of Springbrook Creek. THE CITY OF RENTON DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS FOURTH FLOOR /f 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055-2189 FAX: 235-2541 To: Annette Huxtable Company: Parametrix, Inc Phone: 863-5128 Fax: 863-0946 From: Scott Woodbury Company: City of Renton Phone: 277-5547 Fax: 235-2541 Date: 11/29/93 Pages including this cover page: 3 Comments: Per our discussion attached is a copy of the 6/14/93 Certificate of Insurance. Please revise the cancellation clause of the attached 11/15/93 certificate to match that shown on the 6/14/93 certificate. Thank you. A//'/1r1/® CERTIFICATE OF INSURANCE I CSR CD ISSUE DATE(MM/DD/YY) PARIN-1 11/15/93 PRODUCER THIS CERTIFICATE IS ISSUED AS A MATTER OF INFORMATION ONLY AND CONFERS NO RIGHTS UPON THE CERTIFICATE HOLDER. THIS CERTIFICATE Hurley, Atkins & Stewart, Inc. DOES NOT AMEND, EXTEND OR ALTER THE COVERAGE AFFORDED BY THE 1800 Ninth Ave. , #1500 POLICIES BELOW. Seattle WA 98101 COMPANIES AFFORDING COVERAGE Diane Brooke 206-682-5656 COMPAN LETTER Y A Planet Insurance Co (ECS) _...... COMPANY B INSURED LETTER COMPANY `. LETTER COMPANY Parametrix, Inc. LETTER D P 0 Box 460 Sumner WA 98390 COMPANY E LETTER COVERAGES THIS IS TO CERTIFY THAT THE POLICIES OF INSURANCE LISTED BELOW HAVE BEEN ISSUED TO THE INSURED NAMED ABOVE FOR THE POLICY PERIOD INDICATED, NOTWITHSTANDING ANY REQUIREMENT, TERM OR CONDITION OF ANY CONTRACT OR OTHER DOCUMENT WITH RESPECT TO WHICH THIS CERTIFICATE MAY BE ISSUED OR MAY PERTAIN, THE INSURANCE AFFORDED BY THE POLICIES DESCRIBED HEREIN IS SUBJECT TO ALL THE TERMS, EXCLUSIONS AND CONDITIONS OF SUCH POLICIES. LIMITS SHOWN MAY HAVE BEEN REDUCED BY PAID CLAIMS. CO TYPE OF INSURANCE POLICY NUMBER POLICY EFFECTIVE POLICY EXPIRATION LIMITS LTR DATE(MM/DD/YY) DATE(MM/DD/YY) GENERAL LIABILITY GENERAL AGGREGATE $ COMMERCIAL GENERAL LIABILITY PRODUCTS-COMP/OP AGG. $ CLAIMS MADE OCCUR. PERSONAL&ADV.INJURY $ OWNER'S&CONTRACTOR'S PROT. EACH OCCURRENCE $ FIRE DAMAGE(Any one fire) $ MED.EXPENSE(Any one person)'. $ AUTOMOBILE LIABILITY COMBINED SINGLE ANY AUTO LIMIT S ALL OWNED AUTOS BODILY INJURY SCHEDULED AUTOS (Per person) S HIRED AUTOS _. .... ' BODILY INJURY S NON-OWNED AUTOS - (Per accident) GARAGE LIABILITY PROPERTY DAMAGE $ EXCESS LIABILITY EACH OCCURRENCE $ UMBRELLA FORM AGGREGATE $ OTHER THAN UMBRELLA FORM STATUTORY LIMITS WORKER'S COMPENSATION _... . EACH ACCIDENT $ AND DISEASE—POLICY LIMIT $ EMPLOYERS'LIABILITY - --- - - -- DISEASE—EACH EMPLOYEE $ OTHER A'Professional NTF201587601 11/12/93 11/12/94 11000,000 each claim Liability 2,000,000 Aggregate DESCRIPTION OF OPERATIONS/LOCATIONS/VEHICLES/SPECIAL ITEMS RE: Project #55-1779-07, Wetland Mitigation Banks. CERTIFICATE HOLDER CANCELLATION SHOULD ANY OF THE ABOVE DESCRIBED POLICIES BE CANCELLED BEFORE THE EXPIRATION DATE THEREOF, THE ISSUING COMPANY WILL ENDEAVOR TO MAIL 30 DAYS WRITTEN NOTICE TO THE CERTIFICATE HOLDER NAMED TO THE City Of Renton LEFT, BUT FAILURE TO MAIL SUCH NOTICE SHALL IMPOSE NO OBLIGATION OR Attn: Scott Woodbury LIABILITY OF ANY KIND UPON THE COMPANY, ITS AGENTS OR REPRESENTATIVES. 200 Mill Ave. S. Renton WA 98055 AUTHORIZED REPRESENTATIVE ' Diane Brooke ACORD>25-S (7190) 6UACORD CORPORATION 1990 PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT Y MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 i 0 UTILITY SYSTEMS DIVISION - 235-2631 ' NT 0 TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: JOB NO.: RE: ATTN: GENTLEMEN: WE ARE SENDING YOU ❑ ATTACHED ❑ UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: ❑ SHOP DRAWINGS ❑ PRINTS ❑ REPRODUCIBLE PLANS ❑ SPECIFICATIONS ❑ COPY OF LETTER ❑ COPIES DATE NUMBER DESCRIPTION AND REMARKS THESE ARE TRANSMITTED AS CHECKED BELOW: ❑ FOR APPROVAL ❑ APPROVED AS SUBMITTED o RESUBMIT COPIES FOR APPROVAL o FOR YOUR USE ❑ APPROVED AS NOTED ❑ SUBMIT COPIES FOR DISTRIBUTION ❑ AS REQUESTED ❑ RETURNED FOR CORRECTIONS o RETURN CORRECTED PRINTS o FOR REVIEW AND COMMENT ❑ ❑ PRINTS RETURNED AFTER LOAN TO US COPIES TO: SIGNED TITLE IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE 4 THE CITY OF RENTON i DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS `' : FOURTH FLOOR 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055-2189 FAX: 235-2541 l FAXTRANSMITTA-L DATE: l `) TO: 1l/ � l�L FAX#: FROM: d PHONE#: 277�'S�S�1 SUBJECT: 677 6 Ntlmbcr of pagcs excluding cover shccc I/1:vm</miK/PAXCOV lilt.nO(:/hh + l. 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I . . . . �l PLANNING/ BUILDING/ PUBLIC WORKS DEPARTMENT r��Y O MUNICIPAL BUILDING 200 MILL AVE. SO. RENTON, WASH. 98055 v !� a UTILITY SYSTEMS DIVISION - 235-2631 NT TRANSPORTATION SYSTEMS DIVISION - 235-2620 TO: DATE: JOB NO.: RE: ATTN: GENTLEMEN: WE ARE SENDING YOU ❑ ATTACHED ❑ UNDER SEPARATE COVER VIA THE FOLLOWING ITEMS: ❑ SHOP DRAWINGS ❑ PRINTS ❑ REPRODUCIBLE PLANS ❑ SPECIFICATIONS ❑ COPY OF LETTER ❑ COPIES DATE NUMBER DESCRIPTION AND REMARKS THESE ARE TRANSMITTED AS CHECKED BELOW: ❑ FOR APPROVAL o APPROVED AS SUBMITTED ❑ RESUBMIT COPIES FOR APPROVAL ❑ FOR YOUR USE ❑ APPROVED AS NOTED ❑ SUBMIT COPIES FOR DISTRIBUTION ❑ AS REQUESTED ❑ RETURNED FOR CORRECTIONS ❑ RETURN CORRECTED PRINTS ❑ FOR REVIEW AND COMMENT ❑ ❑ PRINTS RETURNED AFTER LOAN TO US COPIES TO: SIGNED TITLE IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE THE CITY OF RENTON i DEPARTM ENT OF PLANNING/BUILDING/PUBLIC WORKS FOURTH FLOOR I ; 200 MILL AVENUE SOUTH I _ RENTON, WASHINGTON 98055-2189 a R FAX: 235-2541 FAX TRANSMITTAL DATE: A �J��� TO: ��</ ��-�/FG S FAX#: FROM: PHONE#: SUBJECT: ( L Number of pages excluding cover sheet: 1 VI:,n»:/n,�<c/�nXCt)vlilt.l)t>C:/hh NOV-10-93 WED 10;05 PARAMETRIX FAX NO, 206 889 8808 P. 01/15 Parametrix, Inc. 5808 Lake Washington Blvd. N.E. Kirkland, WA 98033 206-822-8880 FAX TRANSMISSION COVER PAGE FAX #206-889-8808 To: R.4n...��Yra,�Ca Fax #: 2-35- 254 t From: .......................................................... Date: ci Number of Pages (Total): _.. ..._....---:._._..._................. Comments: Jn4<Y0,M COr�75 Me-morancW m o� fro[d Ire,)Lo - � Qyd (�vYM d Ml fwLp h tv, t ra b i CENPS-OP-RG MEMORANDUM FOR RECORD: FIELD REVIEW AND JURISDICTIONAL SUMMARY DATE: 24 September 1993 APPLICANT: City of Renton (Glacier Park Company) REFERENCE/FILE NUMBER: 91-4-00149 and 91-4-00099 RELATED FILE NUMBERS: 91-4-00095, 91-4-00096, 91-4-00097, 91-4-00098 (Glacier Park) ; 91-4-00062 (Intrawest Corporation) ; 91-4-00212 (Pace Corporation) ; 92- 4-00019 (Home Club Corporation) . PROJECT NAME: City of Renton Mitigation Banking WETLAND CONSULTANT: Parametrix, Inc. , Tracy McKenzie LOCATION (Topog, S,T,R, City, County, drainage) : Mitigation Bank Site 1 is located north of Southwest 33rd Street and west of Oakesdale Avenue; Mitigation Site Bank 2 is located south of SW 34th Street, east of Oakesdale Avenue SW and northwest of SW 39th Street. Both sites are in Section 25, Township 23 North, Range 4 East, Renton, Washington. PROJECT PURPOSE/DESCRIPTION & BACKGROUND: Nationwide Permit 26 was issued for all the referenced files (except 91-4-00149, Mitigation Site 1, which was issued a wetland confirmation only) . Nationwide Permit 26 was issued only for Lot 3, approximately 5.05 acres, of application number 91-4-00099 (Orillia Block 8, now referred to as Mitigation Bank Site 2, is a total of 15.15 acres) . The Corps issued a confirmation of the wetland delineation for the entire site. Mitigation Site 1 is approximately 31 acres in size. The city of Renton, negotiated and executed an agreement with the Glacier Park Company. The agreement allowed Glacier Park approximately 5 .33 acres of wetland fill on their properties (not to exceed more than one acre/per property, as conditioned by NWP 26) in exchange for approximately 46 acres of nearby property owned by Glacier Park (which contains a total of approximately 23 .6 acres of wetlands; approximately 18.78 acres of wetlands were confirmed for Mitigation Site 1 and approximately 4 .83 acres of wetlands were confirmed for Mitigation Site 2) . Originally, the city of Renton, was going to require on-site mitigation for filling any wetlands on each of the referenced sites. However, in lieu of piecemeal mitigation, Renton executed the Mitigation Bank Site exchange so that more contiguous and comprehensive mitigation could occur in the area in hopes of restoring some of the lost functions and values associated with the hundreds of acres of fill placement in this area in the 1970's . Our wetland confirmation letter for application 91-4-00149 to the Glacier Park Company for Mitigation Bank Site 1 (which is now owned by city of Renton) did not issue a jurisdictional determination for the subject site. The letter, dated 28 February 1992 (enclosed) , states " [w]e have not determined permit requirements. When you have a specific development plan, you may reapply and we will determine requirements at that time. " As stated previously, the NWP 26 letter for application 91-4-00099, was for Lot 3 (5 acres out of the total of 15) Lot 3 is the northernmost lot on the corner of SW 34th Street and Oakesdale Avenue SW. The wetlands on Lot 3 are isolated from Springbrook Creek. The Memorandum for Record pertaining to this site states " [t]he wetlands on this project site are perched, isolated depressions . There is no hydrologic connection between this site and other waters of the United States . The Corps of Engineers can take jurisdiction on these wetlands based on their possible use by migratory birds . " The MFR also states that " [t]he additional 0 . 66 acres of wetlands on Lot 3, as well as the wetlands contained on Lots 1 and 2 of the total site will be set aside in a Native Growth Protection Area. Any work in these wetlands will require further notification and/or authorization from COE. " -2- The wetland report, prepared by David Evans and Associates, Inc. , dated 16 November 1991, for the subject site (Orillia Block 8, Lots 1, 2, and 3) did not contain an adjacency or above the headwaters determination. Therefore, confirming the delineation based on this report did not lock the Corps into a jurisdictional determination for the remainder of the property (Lots 1 and 2) , and NWP 26 for Lot 3 was specifically for that Lot, not for the rest of the parcel. A letter dated 25 August 1993 was received from the city of Renton requesting the Corps complete the jurisdictional determination (JD) regarding the adjacency status of the wetlands within the parcels. The city of Renton has requested a JD because the results of the JD will assist the City to move forward with developing a comprehensive mitigation program that may include mitigation banking for some wetland impacts within the Black River drainage basin. The City also stated that the results will be used by the project team and the City to develop site specific plans to convert the existing uplands on the parcels to wetlands and potentially restore the existing wetlands. In addition, the City and consultant team requested written guidance ont he type and extent of permitting and regulatory requirements associated with converting the uplands to wetlands and restoring the existing wetlands on these parcels (i.e. the difference between requirements associated with an individual 404 permit versus nationwide permit) . SITE DESCRIPTION, NWI: See attached, original MFR's and Corps letters for the respective sites. (Enclosure 1 for Mitigation Bank Site 1, Enclosure 2 for Mitigation Bank Site 2) The NWI showed no wetlands within Mitigation Bank Site 2 and identified on wetland, a palustrine, scrub-shrub, seasonally flooded community in Mitigation Bank Site 1. This wetland included Wetland M on site 1. SITE VISIT (Date/attendees) : 14 September 1993 . Gail Terzi and T.J. Stetz from the Corps met with Tracy McKenzie from Parametrix and Scott Woodbury, and Mary Lynn Myer from the city of Renton on site. The purpose of the site visit was to determine jurisdictional parameters in terms of adjacency. WETLAND REPORT (Yes-Date/No) : Yes, dated 16 November 1991 for Mitigation bank Site 2 and 3 December 1991 for Mitigation Bank Site 1. Both reports were prepared by David Evans and Associates, Inc. CONFIRM DELINEATION (Yes/No) : Yes. For Mitigation Bank Site 1 the wetland delineation was confirmed by Corps letter dated 28 February 1993 and for Mitigation Bank Site 2 the wetland boundaries were confirmed by Corps letter dated 20 April 1992 . For more information refer to wetland reports referenced above. JURISDICTIONAL DETERMINATION AND DISCUSSION (Isolated-Migratory Bird Use, Above Headwaters, Adjacency, IP or NWP) : The wetlands on both the mitigation banking sites are adjacent to Springbrook Creek, a waterway with a mean annual flow greater than 5 cfs. (see Enclosure 3) . Mitigation Bank Site 1 contains wetlands which are continuous with a large wetland parcel owned by the city of Renton, immediately adjacent to Springbrook Creek. The original MFR for this site contained some erroneous information. The information in this MFR supersedes that presented in the original MFR (see enclosure 1) . The original MFR stated (in discussion of jurisdictional determination section) ' [t]he wetlands on this project site consist of some perched, isolated depressions, with some wetlands adjacent to the man-made drainage ditch running along the western boundary of the property and the more -3- natural, prolific and diverse forested wetland communities scattered throughout the site but most significantly on the northwest portion of the site. The drainage ditch along the western edge of the site appears to be connected with an open water wetland to the southeast of the site and from there to Springbrook Creek, which at that portion is above the headwaters. The wetlands on the site do not lie within the 100-year floodplain of Springbrook Creek. The Corps of Engineers can take jurisdiction on these wetlands based on their possible use by migratory waterfowl. " The information about the headwaters of Springbrook Creek is incorrect. This information was obtained from the city of Renton at the time and was not independently verified. The mean annual flow of Springbrook Creek has been defined by the Washington State Department of Ecology Shoreline designation for the area and is 20 cfs to SW 43rd Street (this is where the 20 cfs designation for shoreline permitting ends) . This cfs data includes the project vicinity as described in this MFR. Therefore, the sites are well below the headwaters (S cfs) of Springbrook Creek. This information was verified with the City of Renton on 4 October 1993 . In addition, the drainage ditch is culverted across a right- of-way road to the east and are contiguous with wetlands owned by the city of Renton and adjacent to Springbrook Creek. This area contained quite a bit of standing water during our most recent site visit. It is likely that these wetlands are flooded by high waters overbanking Springbrook on a regular and periodic basis. The original MFR also included the following discussion on NWP or IP: "Further analysis would be required before this determination was made. . . .An adjacency determination would be needed before any work could begin on this site. The site is situated in the Green River floodplain. The drainage ditch on the site appears to be above the headwaters, however further review is recommended when a final plan to restore this site as a wetlands mitigation bank is received. " This MFR constitutes further review. In addition, more information through the Seattle District's internal guidance on adjacency calls has set up a more detailed and methodical approach to determining adjacency. Mitigation Bank Site 2 also contains wetlands continuous to Springbrook Creek. The difference between Lot 3 wetlands (depicted as 8W on the enclosed map) and the wetlands on the remainder of the site (on Lots 1 and 2) are their location in reference to Springbrook Creek. The Lot 3 wetlands are isolated depressions separated by a large upland area between them and Springbrook Creek. The other wetlands on the southern end of the parcel continue in a continuous band all the way to the banks of Springbrook Creek. The wetlands on Lots 1 and 2 are more mature and connected than those found on Lot 3 . The Lot 1 and 2 wetlands are scrub/shrub and forested wetlands, with a smaller component of reed canary dominated palustrine emergent wetlands. Wetland H (see enclosure 4) is separated from Springbrook Creek by a man made levee and as such can not be considered in establishing adjacency. Any impacts to wetlands due to mitigation efforts in the banking sites 1 and 2 will require an individual Department of the Army permit. This now includes excavation of wetland areas to create open water systems and the like (see excavation ruling, 33 CFR Parts 323 and 328, dated 2S August 1993) . ADDITIONAL COMMENTS: Recommend that we inform the city of Renton of our adjacency findings, enclose signed MFR with letter, and assign new application numbers to Mitigation Bank proposal (s) when they are submitted. -4- - O l0 5 10 Project M nager Env gonmenn Analyst Gail Gail Te i T.J. Stetz' /9 e�'3 Section 4Chief Bob Martin GN C U E 1 Regulatory Branch FEB 2 8 1992 M ttl�pih'dY� �an� rt�, Mr. Marty Sevier • Glacier Park Company 1011 Western Avenue, Suite 700 Seattle, Washington 98104 Reference: 91-4-00149 Dear Mr. Sevier: Glacier Park Company This is in response to your request for a confirmation of a wetlands delineation performed by David Evans and Associates, Inc. , acting on your behalf, for wetlands located on your property (approximately 31 acres) situated immediately north of Southwest 33rd Street and west of Oakesdale Avenue in the City of Renton, King County, Washington. We concur with the wetlands delineation presented in the report, dated December 3, 1991, by David Evans and Associates, Inc. and confirmed by a site inspection of the subject property performed on February 5, 1992. The information contained in the report and associated drawings appears accurate and complete. This delineation is valid for a period of 3 years from the date of this letter. We have not determined permit requirements. When you have a specific development plan, you may reapply and we will determine requirements at that time. We have canceled this file, but please refer to the reference number if you reapply. This does not excuse you from compliance with or confirmation from other Federal, state, and local statutes, ordinances or regulations which may affect this work. If you have any questions, please contact Ms. Gail Terzi, telephone (206) 764-3495. Sincerely, 0- Robert H. Martin Chief, Processing Section MAR'r1N 0-96 cc: David Evans and Associates, Inc. T-ILFJ 415 - 118th Avenue, S.E. Bellevue, Washington 98005-3553 Department of Ecology P.O. Box 4770 Olympia, Washington 98504-7703 i I k i a , : r.:iv�c�iC+uuf1 FUK KEGURD: FIELD REVIEW AND JURISDICTIONAL SUMMARY APPLICANT: Glacier Park Company 1011 Western Avenue, Suite 700 Seattle, Washington 98104 REFERENCE: 91-4-00149 AGENT: Mr. Mark Stiefel KPFF Consulting Engineers 1201 Third Avenue, Suite 900 Seattle, Washington 98101 WETLAND CONSULTANT: Mr. Tom Duebendorfer David Evans and Associates, Inc. 415 - 118th Avenue, S.E. Bellevue, Washington 98005-3553 PROJECT DESCRIPTION: The applicant proposes, to construct wetlands by excavation and removal of prior fill and usng restoration techniques for the purpose of a future wetland mitigation bank. Disturbance to the existing wetlands is expected. The applicant has requested a wetland delineation confirmation on this project, since a final plan for the mitigation site has not been developed to date. PROJECT LOCATION (S/T/R. City, County, drainage) : The project (Orillia Parcel #14) is located north of Southwest 33rd Street and west of Oakesdale Avenue Southwest in Section 25, Township 23 North, Range 4 East, Renton, King County, Washington. SITE VISIT: Gail Terzi and Susan Glenn inspected the site on February 5 , 1992. Tom Duebendorfer from David Evans met us on site. SITE DESCRIPTION (Topography, etc. ) : The total acreage for the site is approximately 31 acres and contains approximately 19 acres of wetlands (Exhibit A) . The site is a composite of recently disturbed and relatively undisturbed areas. Approximately a third of the site was legally filled about 20 years ago. The more recently disturbed areas were either cleared or cleared and filled. The topography is generally flat, with the filled areas being somewhat elevated in relation to the undisturbed areas ; one area, about an acre in size, has about a 4-foot high mound of fill material. A 6-foot wide drainage channel runs north-south along the western boundary of the site The site is zoned for industrial use and is bordered by developed commercial/industrial lands along the eastern half of the southern boundary. Undeveloped commercial/industrial lands lie adjacent to the western half of the southern boundary and to the eastern and western boundaries. The lands adjacent to the north and to the northeast are rural , forested and undeveloped and contain protected wetlands. The undisturbed part of the 31 acres consists of grassland, shrubland, and woodland areas . 4 poop WETLAND REPORT (YES/NO) : The applicant provided a vetlarkd report by David Evans and Associates, Inc. , dated December 3, 1992. The reeland " delineation on the site was done in accordance with the Corps of ng „=x, Wetland Delineation Manual (1987 manual) . CONFIRM DELINEATION (YES/NO) : Yes. INDICATORS (Vegetation, soils, hydrology-what is call based on?) : Total 3 area of wetlands identified within the boundaries of the site is 18. 78 acres. The wetlands range from 0. 14 to 17.91 acres in size. Two of the identified wetlands would be classified as palustrine, scrub-shrub wetlands. The remaining wetland, the largest on the site, would be classified as a mosaic of palustrine wetland classes: including emergent marsh, scrub-shrub, and forested. All three wetlands are seasonally flooded. During our site visit the wetland areas were either ponded or inundated and the soils in the natural areas were clearly hydric, with evidence of oxidation and Munsell Chart readings at 10 inches of approximately 10 YR 3/1-4/1 with medium and distinct mottling. These soils are listed as mostly Woodinville silt loam with a small area of Puget silty clay loam. The- texture of these wetland soils were a fine sandy loam. The wetland soils in disturbed areas of the site were clearly gravelly fill material which were at times many feet thick. The disturbed areas were dominated by reed canary grass in wetland areas and Himalayan blackberry on the upland portions. The largest of the wetlands were contained to the northwestern part of the site and was dominated by mature black cottonwood, willows,dogwood, with an herbaceous layer of buttercup, soft rush and horsetails. A complete list of plants is provided for in the enclosed wetland report. DISCUSSION OF JURISDICTIONAL DETERMINATION (Isolated, migratory birds, above headwaters , adjacent. Include calculation of CFS, etc. ) : The wetlands on this project site consist of some perched, isolated depressions, with some s wetlands adjacent to the man-made drainage ditch running along the western boundary of the property and the more natural, prolific and diverse forested wetland communities scattered throughout the site but most significantly on the northwest portion of the site. The drainage ditch along the western edge of the site appears to be connected with an open water wetland to the southeast of the site and from there to Springbrook Creek, which at that portion is above the headwaters. The wetlands on the site do not lie within the 100-year floodplain of Springbrook Creek. The Corps of Engineers can take jurisdiction on these wetlands based on their possible use by migratory waterfowl. NWP OR IP (Discuss reasons) : Further analysis would be required before this determination was made. The applicant is requesting a confirmation of the wetland delineation, which was confirmed on the site inspection. The wetland delineation report appears accurate and complete. An adjacency co determination would be needed before any work could begin on this site. The site is situated in the Green River floodplain. The drainage ditch on the 4 site appears to be above the headwaters, however further review is recommended when a final plan to restore this site as a wetlands mitigation ' bank is received. fi A nuuaalvla la. vv.uli.ir a.� ai�t �auJ t;VL S1Ce appears to be wall ■uit�d end ��"" situated for mitigation because of the existence of a diverse wetland community and the capabilities for expansion, enhancement and creation. This site is also advantageous for wetland mitigation because it is situated next to a City of Renton parcel which already contains protected wetlands. There is the possibility that this site could be connected by trail and/or wetlands enhancement to the City's site. Gail Terzi 11 reb 92_ T.J. Stetz Project manager Environmental Analyst Robert H. Martin Chief, Processing Section h u i� S f 2 0 1�rn • �1 GLoS v� Z 1 / I Regulatory Branch Mr. Marty Sevier Glacier Park Company 1011 Western Avenue, Suite 700 Seattle, Washington 98104 Reference: 91-4-00099 Glacier Park Company Dear Mr. Sevier: We have confirmed the wetland delineation on- the 15.15 acre, Orillia Block 8, Lot 1, 2, and 3 site located south of SW 34th Stre 1, east of Oakesdale Avenue SW and northwest of SW 39th Street in Section , Township 23 North, Range f�East, Renton, Washington. We are in agreement with the delineation report prepared by David Evans and Associates, Inc. , dated November 16, 1991. This confirmation of delineation is valid for a period of three years from the date of this letter. We have also evaluated your proposal to discharge fill material into 0.99 acres of wetlands, located on Lot 3 of the Orillia Block 8 site, which are isolated. Department of the Army regulations dated November 22, 1991, authorize certain activities under nationwide permits, provided the enclosed conditions are met. Nationwide Permit 26 (Part 330, Appendix A) authorizes discharges of dredged or fill material into nontidal rivers, streams, and their lakes and impoundments, including adjacent wetlands, that are located above the headwaters where the average annual flow is less than 5 cubic feet per second . . . . The entire text of Nationwide Permit 26 is enclosed. Prior to placing fill, you must contact the Washington State Department of Ecology to determine whether documented habitat for a state listed species is present. If present, this nationwide permit is not valid and you must contact us again to determine permit requirements. Please contact: State Nationwide Permit Coordinator i Department of Ecology P.O. Box 47703 Olympia, WA 98504-7703 j Telephone (206) 438-7514 or 459-6038 j i We suggest that you place the following statement on the project plat as information to future property managers: Contact the Corps of Engineers about permit requirements for work in wetlands. -L_ This verification will be valid for two or until the nationwide permit is modified years from the date of additional placement of fill in waters of the eUnited�States, inc or luding this letter wetlands, is contemplated on this site If additional permit requirements, r You must contact us concerningany ad you must still requirements. complyWhile you need no further authorization from which may pertain to the orth other Federal, State and local requirements Ms. Gail Terzi at the above address If orhave any questions, y telephone at please contact (206) 764-3495. Sincerely Robert H. Martin Enclosures Chief, Processing Section cc: EPA; DOE; David Evans & Associates, Inc. ; Mark Stiefel 415 118th Ave. , SE Bellevue, WA 98005-3553 Keentt,,2 WA A 9 Ave. SE 98031 M44TIN op-Q-6 iZ E11 I i CENPS-OP-RG MEMORANDUM FOR RECORD: FIELD REVIEW AND JURISDICTIONAL SUMMARY APPLICANT: Glacier Park Company loll Western Avenue, Suite 700 Seattle, Washington 98104 REFERENCE: 91-4-00099 , Orillia/Renton Parcel 8 West/Lot3 AGENT: None. WETLAND CONSULTANT: David Evans & Associates, Inc. I PROJECT DESCRIPTION: The applicant proposes to build a commercial warehouse on this site. PROJECT LOCATION (S/T/R. City, astCounty, drainage) : The project is located west of Springbrook Creek, south of1SWS34 th Street, 30, townshipo230Nordth1eRangeu C 5 SW. and northwest of SW. 39th St. , East, Renton, King county, Washington. The site plan shows Lots 1, Z and 3 for this parcel. The project is limited to Lot 3 which is the northernmost lot on the corner of SW. 34th St. and Oaksdale Ave. SW. SITE VISIT: Jack Gossett and Gail Terzi inspected the site on January 24, 1992. SITE DESCRIPTION (Topography, etc. ) : The total acreage for the parcel is 15.15 acres with 6 .48 acres of total wetlands (22ot000 square feet)of be developed. Lot 3 is approximately 5.05 contains 1. 65 acres of wetlands, of which 0.99 is proposed for filling. Lot ith 3 is a 5.05 acre commercial ewllding inchesstoea maximum in depth. _ depressions ranging from a f The project site, as well asoallong before of the rCOEnjurgsdiction was underfilled thebClean City of Renton many year g Water Act. The area is surd by _found onercial development those depressions ondtheasite The existing wetlands on the site ae where surface rain water collects. WETLAND REPORT (YES/NO) : The applicant provided a wetland report completed by David Evans and Associates, Inc. , dated November 16, 1991. The wetland delineation on the site was done in accordance with the Corps of Engineers Wetland Delineation Manual (1987 manual) . ti CONFIRM DELINEATION (YES/NO) : Yes. is call based on?) : The soils INDICATORS (Vegetation, soils , hydrology-what {4 r r ,. . on the uplands and on the wetlands on the Lot 3 project site are non-hydric, fill.rlier to highly compacted, cementedsoilinf om eaoil. - The wetland impossible delineation dig holes deeper than 6 inc hes thos areas completed based on vegetation consisted ofaicombinationsof On uplandupland called wetlands, vegplant with a predominance of wetland species. and facultative plant species, art of the wetland These species are listed on the data sheets which are a p delineation report. DISCUSSION OF JURISDICTIONAL DETERMINATION (Isolated, migratory wetlandsabove headwaters, adjacent. Include isolatedl depressions. There is no hydrologic this project site are p connection between this site and other naonrtheses of twetlandsdbasedeon their Corps of Engineers cantake�ke 3 s �'�5' possible use b migratory -�1 e a total of 1.65 acres of wetlands NWP OR IP (Discuss reasons) : There wer site. The applicant propos wetlands to fill 0.99 acres of the on the Lot 3 project ro ect site s isolated. The project wetlands for this project. Thep i j qualifies for a Nationwide Z act to less than one acre of wetlands. Theeadditi location onal O.66acresofnwetlands on Lot 3, te will as well as the wetlands contaP�odection on tArea and Any workeinotheselwetlands e set aside in a Native Growthfrom will require further notification and/or authorization proposed project. . This information will be included in the site plans ADDITIONAL COMMENTS: None. T.J . Stetz Gail Terzi Environmental Analyst Project manager Robert H. Martin Chief, Processing Section I I i � ' i bbo00-�-Ib I i I y i II ! Q Ii 57JJ6 CJ.I�y: B7�V'Dl!Cj lew I I O - 00° Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd.N.E. Kirkland,WA 98033-7350 206-822-8880•Fax:206-889-8808 V Mr. Ronald J. Straka November 11, 1993 City of Renton 55-1779-07 200 Mill Avenue South Renton, Washington 98055 Dear Mr. Straka: Enclosed are four copies of Chapters 1 through 6 of the draft mitigation plan and program for the City of Renton Wetland Mitigation Bank for your review and comments. Chapter 7 (Public Involvement), Chapter 8 (Programmatic Mitigation Banking Plan), and Chapter 9 (Technical Mitigation Banking Plan) are being completed and will be sent for your review under separate cover. The alternative site plans will be included with Chapter 9. When the City and Parametrix were finalizing the scope of work, we indicated that three alternative site plans would be developed. They included: (1) an overall site plan for the mitigation areas (assumes full mitigation development), (2) site plan for mitigation development between 5.5 and 19.35 acres, and (3) a site plan for the 5.33 acres of impacted wetland from the Glacier Park properties. All three site plans assume that the existing wetlands will not be disturbed. As this project has progressed we believe that there are alternative site plans that are more reasonable than the three site plans identified above. Based on the paucity of information on Mitigation Banking Site 1 (north site) and our discussion on October 18, 1993, we propose to develop a conceptual plan that converts the uplands to wetlands and minimizes impacts to the existing wetland system. However, this site plan would reflect some alteration of the lower quality portions of the existing wetlands and potential phasing of mitigation. The second site plan will show full build out of Mitigation Banking Site 2 (south site) including alteration of the existing wetland systems. The third site plan will show full build out of the uplands on Mitigation Banking Site 2 and minimal impact to the existing wetlands. We want to meet with the City to present and discuss these conceptual plans. If the City approves the conceptual plans we could use them during a meeting with the agencies and the public. Final detailed plans for Mitigation Banking Site 2 and a revised conceptual plan for Mitigation Banking Site 1 would be prepared based on input from the City, agencies, and public and be included in the final plan. Finally, please note that Chapter 6 ends with a discussion of the feasibility of a mitigation banking program. We have prepared this document with the idea that the City would implement a mitigation banking program versus and off-site mitigation banking program. In addition, the City has almost always presented this project as a mitigation banking project. However, I included a discussion of an alternative to mitigation banking—concurrent mitigation—in this �0� Printed on Recycled Paper L® Mr. Ronald Straka City of Renton November 11, 1993 Page 2 chapter for purposes of comparison. Raising the possibility of an alternative mitigation program for the City to consider may seem out of context in this Chapter, or the entire document, if the City has already agreed that they want a mitigation bank. Please let me know your thoughts on this issue. If the City has not agreed that they want a mitigation banking program, I could present this topic as an issue in Chapter 3. Please call me at (206) 822-8880 if you need more information or have any questions. Sincerely, PARAMETRIX, INC. &� fncja+ Tracey P. McKenzie cc: Bill Shiels - Talasaea project file enclosures t • Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd.N.E. Kirkland,WA 98033-7350 206-822-8880•Fax:206-889-8808 i. 1993 CITY OF RtNTOI'3 Mr. Ronald Straka Engineering Dept. November 4, 1993 City of Renton 55-1779-07 200 Mill Avenue South Renton, Washington 98055 Dear Mr. Straka: Subject: Additional Information Needs for Mitigation Banking Site 1 As we discussed during the Monday, October 18, 1993 meeting, the level of information available for Mitigation Banking Site 1 is inadequate to prepare a detailed site plan. The City requested that we submit a letter indicating the type of information needed before a site plan can be prepared. Below is a list of data and information needs for your consideration: Information Need Timing Survey property boundaries late fall, winter 1993 Survey P-1 channel easement late fall, winter 1993 Elevation survey of site at 0.5-ft contours' late fall, winter 1993 (including the ditch along western and northern boundary of the site). Have the surveys also map the utilities (especially electrical) right-of-ways, and easements! Monitor groundwater (see attached map for install and monitor fall, suggested locations) winter, 1993 and spring, summer 1994 Install temporary V-notch weir to measure install late fall 1993,monitor weekly flow in ditch in southwest corner of site through winter 1993/1994,spring and summer 1994 ' S ft contours are suggested because the site is relatively flat. 2 This infonnation is needed to detennine appropriate locations for a potential parking area for public access/educational opportunities. �0� Printed on Recycled Paper Mr. Ronald Straka City of Renton November 4, 1993 Page 2 Identify where the water comes from that enters late fall, winter 1993 into the ditch along the western and northern border of the site. If possible determine the quality of the water. Please call me at (206) 822-8880 if you have any questions regarding this letter or need more information. Sincerely, PARAMETRIX, INC. Tracey P. McKenzie cc: project file Scott Woodbury T t$. 18 .. W — 12 HIGH FLOW DIVERSION CHANNEL IMPROVEMENT ; 16 Y Upland endow an shr land co munity WETLAND M: - 1 : : . 1-8 . Young, forested, shrub, and emergent wetland communtity WETLAND M :.. : W - 22 3 8 i W - 22 20 W 2 W — 2 WETLAND L: WETLAND J:Shrub community Shrub community o r c m y .. .. . Upland meadow and shrubland community W _ 14 W - 45 : :. Ins+Q cir here - - - - - - - - - - - — _ _ _ _ _ _ � SW 33rd _ W-22 = Wetland code from FIGURE Parametrix, Inc. DRAFT Jones and Stokes, 1991 EXISTING CONDITIONS OSCALE 7N FEET O October 19, 1993 SOURCE: — — — = Mitigation site boundary MITIGATION SITE 1 CITY OF RENTON, 1993 � = Soil Test Location (approximate) 40 Su99es+ed ground weer WWLtom 10co-1-1tvi NOV- 8-93 MON 10:45 PARAMETRIX FAX NO. 206 889 8808 P, O1/04 MEMORANDUM to: Scott Woodbury - City of Renton November 8, 1993 from: Tracey McKenzie - Parametrix, Inc. re: Information for Meeting with U.S. Army Corps of Engineers Enclosed is information that may be helpful to you in your discussions with the Corps on the jurisdictional determination of wetlands on the mitigation banking sites. Please call me at(206) 822-8880 if you have any questions or require additional information. FAX TRANSMITTAL *orp; ea To scc;H W3 Fmon TP MCk-M t5 co. co. PARAMETRIX, INC. Dept. Phone (206)822.8880 Fax u 23 S - D 5 t4 f Fax (206}BB9-8808 COMMENTS: i QO - 8-93 MON 10:46 PARAME'N 1 X FAX NO. 206 889 8808 P, 02/04 to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 2 Many areas in the Valley that were filled over the past 20 years were developed; however, some filled areas were not, and depressional areas on the undeveloped sites collected rainwater. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Sites 1 and 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. Without having the benefit of reading the Corps internal memorandum indicating the criteria and rationale used to make the jurisdictional determination, it is my understanding that the Corps has determined that wetlands on Mitigation Banking Site 1 are adjacent because they are contiguous with wetlands to the north and east (the City of Renton wetlands), the City of Renton wetlands extend over to Springbrook Creek, and the City of Renton wetlands periodically experience flooding frorn Springbrook Creek, which in turn may back water into the wetlands on Mitigation 'Banking Site 1, At least one-third of Mitigation Banking Site 1 has either been cleared, or cleared and filled, with gravel and sand from 12 to 48 inches in depth (David Evans and Associates 1991). A 4-foot-high mound of fill material covers approximately 1 acre of the site. In addition to the fill material, the site is also characterized by three soil types: Puyallup fine sandy loam (non-hydric), Woodinville silt loam (hydric), and Puget silty clay loam (hydrie). The non-hydric soil type is the dominant soil type and occurs largely in the central portion of the site and continues to the north and south of the site. As a result of filling activities over the past 20 years the elevation of the wetland areas are estimated to be 2 to 3 feet higher than the City of Renton wetlands and at least 4 to 5 feet higher than Springbrook Creek. The primary source of hydrology for the existing wetlands on Mitigation Banking Site 1 is precipitation. These wetlands are in depressional areas that hold precipitation prior to evapotranspiration and infiltration, A potential secondary source of hydrology for the wetlands on Mitigation Banking Site 1 is the drainage ditch that occurs along the western and northern boundary of the site. Although the elevations of the wetlands and uplands appear to be considerably higher (at least 3 to 4 feet) than this ditch, high flows may overflow the banks of the ditch and enter into the large forested scrub-shrub and emergent wetland. However, the volume, flow rate, and water quality in this ditch system are not known, A relict tributary to Springbrook Creek, once evident within the central portion of the site, has been filled over the years. Surface water is presently diverted away from the relict tributary and flows through the north-south drainage ditch located just inside the western NOV- 8-93 MON 10:47 PARAMETRIX FAX NO, 206 889 8808 P, 03/04 to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 3 boundary of the site, enters into a east-west drainage ditch, then flows east through a culvert under Metro's gravity sewer system and into the City of Renton Wetlands. Once water enters into the City of Renton wetlands, it is retained mithin the wetland and leaves the site through evapotranspiration and infiltration, There is no direct outlet (i.e., culvert or day lighted stream or ditch) from the City of Renton wetlands to Springbrook Creek indicating that under current conditions there is no surface connection between the wetlands on Mitigation Banking Site 1 and Springbrook Creek, Mitigation Banking Site 2 is 13.93 acres. The site consists primarily of herbaceous perennial grasses and forbs, annual forbs, and a fairly large young forested wetland community consisting primarily of cottonwoods and shrubs. The site was filled within the past 20 years, and with a few minor exceptions, the topography is relatively flat with small depressions formed by heavy equipment conducting grading work. Surface elevations range from 15 to 19 feet. These depressional areas developed a perched water level and eventually small lower quality wetlands formed on fill. The existing conditions are that the wetlands on both Mitigation Banking Site 2 have formed on top of fill, are isolated depressional areas, and have developed as pans that are not connected by groundwater or surface water to Springbrook Creek. The soils on the site are mapped as Woodinville silt loam, a hydric soil (Snyder et al. 1973). However, the majority of the site consists of fill material. The site has been driven on and the compactions, coupled with the type and nature of the fill material, have resulted in a relatively dense, hard surface, especially in the areas where wetlands have formed on top of the fill. The hydrology source for the existing wetlands on Mitigation Banking Site 2 is precipitation. Wetlands on this site lack an obvious inlet or outlet. The Corps considers these wetlands to be adjacent because they are contiguous with Springbrook Creek, However, the elevation of the wetlands are at least 6 to 7 feet higher than the elevation of Springbrook Creek at low flow (surface elevation of 10 feet). During a 100-year storm event under current conditions water flows at about 850 cfs and the water surface elevation of Springbrook Creek near Oaksdale Avenue would be about 16.4 feet, This means that if the dike were removed water could enter into the wetland at the northeast corner of the site (at elevation of about 16 feet) during a 100-year storm event. It would take a storm event greater than the 100 year storm event to flood all of the existing wetlands with the dike removed. Even if water did get into the wetlands on Mitigation Banking Site 2, it is important to know the duration of inundation or soil saturation. The City should discuss the opportunity of monitoring the duration and soil saturation in the wetlands to determine if ponding occurs for a long duration [i.e,, at least 2 weeks in the growing season (March 1 through October 31)], or if the soils are flooded for a long duration (i.e, at least 2 weeks during the growing NOV- 8-93 MON 10:48 PRRRMETRIX FAX NO, 206 889 8808 P. 04/04 to: Scott Woodbury - City of Renton from: Tracey McKenzie - Parametrix, Inc. November 8, 1993 Page 4 season) with the Corps. If ponding or flooding of the v ietland areas does not occur for long or very long duration (i.e, 2 weeks or more during the growing season) the Corps may reconsider their jurisdictional determination for the wetlands on Mitigation Banking Site 2. They City could also discuss the possibility of monitoring the duration of ponding and flooding of the wetlands on Mitigation Site 1 to determine if the Corps would reconsider their jurisdictional determination on these wetlands, However, I am less confident that the Corps will reconsider their jurisdictional determination of the wetlands on Mitigation Banking Site 1 because at least one wetland (Wetland M) occurs in a more or less continuous band with neighboring wetlands that extend over to the banks of Springbrook Creek. C.dFiAY'-a r/64; 11//ol 93 i4 c am! /r*kT/.IV6 111V`z'3 Regulatory Agencies 'K)r Gail Terzi 70-(01103 c.cajAw" $Y* **)(Eric Stockdale `y9-741 CA&,69 I//3 t T. J. Stetts M/p Wash. Dept. of Ecology C k-+ Awg"Vo U. S. Army Corps of Engineers 3190 - 160th Avenue SE P. O. Box 3755 Bellevue, WA 98008 Seattle, WA 98124-2255 �t'1fLIr�oA 5lalbw. L.53.-�,f7$��a�firy Fops Y 553-/y/2 Wr ' iS��� Andy McMillan '1$� �y7-I27t f�'Bill Rile m JoAnne Stellini 75'3- 9Nyv�/�`*'"Ts�k rt� Environmental Protection Agency P.an h State Box 4Deept0. of Ecology � U.S.Alli FishRalph 4/t Mcs S rvice �'u g Y ills tt� 1200 Sixth Avenue - WD-128 Olympia, WA 98504 3704 Griffin Lane SE- STE 102 Seattle, WA 98101 Olympia, WA 9801-2192 75 b7 Z Chuck Natsuhara / -7jKY �A*Joe Robel lel-t54(, aPr w4,XAv t yC Rick Albright 553-4,�ty 4APf ew4' W_A W/S Soil Conservation Service Wash State Dept of Fisheries m16' Dept of Environmental Protection 1/114 Evergreen Plaza Bldg- Room 502 115 General Adm. Bldg. AX-11,,.1% rmfC4 1200 Sixth Avenue 711 Capital Way P O Box 43155 lite Seattle, WA 98101 Olympia, WA 98501 // Olympia, WA 98504-3155 it54Patricia Thompson 7�5-i3i � ►,,ESs,�¢VS*Ginny Broadhurst 16 /"&sf"�*W Rod Den-Herder -7Gy -3315'///3 Wash State Dept of Wildlifil'l/l Puget Sound Water Quality Authority Soil Conservation Service tWl,4- 4-7f6n+o 16018 Mill Creek Blvd. 01141 t" Is P. O. Box 40900 - M/S PV-15 935 Powell Avenue SW Mill Creek, WA 98012 Olympia, WA 98504 Renton WA 98055 Tom Mueller 7U1 3N95- Becky Herbig 775-13/I cnoJs Ayru ' Mary Burg 6-It-7o3i Army Corps of Engineers Wash State Dept of Wildlife E'/S Wash State Dept of Ecology 4735 E. Marginal Way South 16018 Mill Creek Blvd 3190 - 160th f Seattle WA 98124-2255 Mill Creek WA 98012 e WA 98008-5452 . ULY1+MlA L octDD pr o u/S" Ill/t SCR/WI OX wtu ATr)rA %d( �W T°,'t� Q�3�Y �P3t �A+4 ia�,.o. 'f�7'(,SSoB � 10 Anne Watanabe f Norm Stewart VFEV fir Theodore Muller 77y . -eej-L t '4 A A7Ace N�S' Wash State Dept of Ecology Wash State Dept of EcologywL& +w Wash State Dept of Wildlife 3190- 160th Ave SE WQFAP-MS PV-11 ATr" 16018 Mill Creek Blvd Bellevue WA 98008-5452 Olympia WA 98504 l/ Mill Creek WA 98012 �f (Au- A( I N /)."VOA4 )r.f,* CAr* ^TT&P14V)&L nor .AcIU"p )&4 c I(4, A'T kr4 H:DOCS:Agency 1:SSW:ps NvOU- 4-93 THU 18:27 PARAMETRIX FAX NO. 206 889 8808 P. 01/03 Parametrix, Inc. 5808 Lake Washington Blvd. N.E. Kirkland, WA 98033 206-822-8880 FAX TRANSMISSION COWER PAGE FAX *206-889-8808 To: o L YJD 4101 Fax #: 2 3 15- - ac From: !AQ ......................-,...............I......... .... Date: Number of Pages (Total): -----------;?.............. Comments: 0 .............................................................................................................................................................................................I................................................. ..... ITV- 4-93 THU 18:28 PARAMETRIX FAX NO. 206 889 8808 P. 02/03 WETLAND MITIGATION BANKING PROGRAM NOVEMBER 10, 1993 MEETING WITH AGENCIES AGENDA AND FORMAT Opening Ron Straka 2:00-2:10 Background Scott Woodbury 2:10-2:20 Goals, Objectives, and Policies Scott Woodbury 2:20-2:30 Baseline Conditions Tracey McKenzie 2:30-2:45 Site Plans Bill Shiels/ 245-3:20 Tracey McKenzie (interactive discussion with agencies) Permitting Issues Tracey McKenzie 3:20-3:50 Next Steps and Closing Ron Stral:a 3:50-4:00 FORMAT Opening: Introduce City staff and consultants. Identify the purpose of meeting with the agencies:To involve there earlier in the mitigation banking program planning process, seek their technical and regulatory input, etc. Background: Briefly describe the historical nature of the Valley. Describe the events that resulted in changes in the Valley over the bast 20 years. Lead into the arrangement between Glacier Park and the City, and end with how the City acquired the two sites. Goal, Objectives, and Policies: Provide the agencies with copies and describe where the objectives and policies came from, but don't elaborate on the entire list. NUV- 4-93 THU 18:28 PARAMETRIX FAX N0, 206 889 8808 P, 03/03 Baseline Conditions: Describe vegetation, soils, and hydrology associated with existing on-site wetlands, ditto for upland communities. Describe opportunities and technical constraints. Site Plans: Present bubble eiagrams (e.g., 42 inch X 42 inch) of each mitigation banking site showing the types of communities emisioned for the two sites. Describe how they relate -to surrounding wetlands. Have this be an interactive discussion with the agencies and seek their technical input on opportunities to overcome some of the technical constraints. Also let them voice their concerns with mitigation banking programs but ask that if they voice a concern they also have to offer a solution. Permitting Issues: Review the table of federal, state, and local regulatory requirements with the agencies. Make sure we have identified all of the potential permits that may be necessary to undertake the project. Provide opportunity for agencies to give input on their permitting regulatory concerns. Next Step/Closing: Thank the agencies for their time and input. Let them know they will have an opportunity to comment on the mitigation plan. Direct further questions to Scott. NOV- 4-93 THU 11 :43 PARAMETRIX FAX NO. 206 889 8808 P. 01 Z35- 25�! I Gail Terzzi/TJ Stetz - Corps 'l 764-6903 or 764 3495 Joe Robel - Fisheries 902-2566 Eric Stockdale - Ecology 649-7061 Bill Reilly - EPA 553-1412 Fred Weinman - EPA 553-1414 Andy McMillan - Ecology 438-7428 JoAnn Stellini/Alisa Ralph/Curtis Tanner - FWS 753-9440 Jim Schaefer - WSDOT 705-7403 Chuck Natsuhara - SCS, King County 764-3325 Heather Stout - King County SWM 296-8013 Patricia Thornpson/Ted Mueller - WDW 775-1311 or '774-8812 Ginny Broadhurst - PSWQA 493-9300 FAX I K NSMiTTIkL 4 of pages To Sco}� u�otv�b+^y From -TpMck-l- t Ls- Co. Co� PARAMETRIX, INC._ Dept. ?hone (206) 822�880 — Fax 9 Fax 0 (206) 689-8808 C0MNM2;NTS: - THE CITY OF RENTON � i DEPARTMENT OF PLANNING/BUILDING/PUBLIC WORKS ,; FOURTH FLOOR > 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055-2189 FAX: 235-2541 ` . t FAX TRANSMITTAL DATE: l//3153 TO: 7-RAC,0 MCt�N-Zl/ FAX#: (-2-X- -8gU8 FROM: �Q� 000.�Uh PHONE#: 27 7- jay? SUBJECT: W iTl,�W (DiA. �MI-9 /"AP-CH 11. �x�cv�ty� 0(LO'S/L S� CAu, . T"�4/A►ji(�5- , Numbcr of pages excluding cover shccu / THE CITY OF RENTON i DEPARTMENT OF -Z5 PLANNING/BUILDING/PUBLIC WORKS . FOURTH FLOOR I �# y 200 MILL AVENUE SOUTH RENTON, WASHINGTON 98055 2189 +I FAX: 235-2541 , �r 1 FAX TRANSMITTAL DATE: 8908 r-,Aa- TO: 'Aa !/ul cdNIi FAX#: FROM: S(4r 6S N 0gv(zy PHONE#: -2 7,7 - S5q'7 susJEcr: 5ykfzi lyas °►- Gc�h w�T�Pw'�s D�,Ep �'13i93 Slyly. S Ll B SGs < TH 15 `N ko,Ln,\A n uiJ 1 /N "l VF�t-��/,�(� �=AS� �JL /5C"T40 759�ro') QrV Number of pages excluding cover sheet: Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd. N.E. Kirkland,WA 98033-7350 206-822-8880•Fax:206-889-8808 a; Scott Woodbury t3`, ' 93 October 22, 1993 City of Renton �C 19 55-1779-07 200 Mill Avenue S. RE�SO�� Renton, Washington 98055 C,-�( of . pep�� Dear Scott: Enclosed is an invoice for services rendered through September 30, 1993. Work performed during this period included: Task 1A - Project Management Technical support to assist and coordinate with the City. Task 1C - Mitigation Goals and Objectives Kitty Ford worked on preparing policy issues. Task 1D - Conditions Assessment and Field Work Included site visit to assess current conditions, review of background information and begin preparation of conditions assessment chapter. If you have any questions or require additional information, please call me at (206) 822-8880. Sincerely, PARAMETRIX, INC. Tracey P. McKenzie enclosure �0� Printed on Recycled Paper CITY OF RENTON Planning/Building/Public Works Department Earl Clymer, Mayor Lynn Guttmann,Administrator October 25, 1993 Tracy P. McKenzie, Project Manager Parametrix, Inc. 5808 Lake Washington Blvd. NE Kirkland, WA 98033 SUBJECT: CITY OF RENTON WETLAND MITIGATION BANK PLAN Dear Ms. McKenzie: I want to thank you and Bill for your participation in the public meetings of October 20 and 21, 1993. You both gave good presentations and provided valuable assistance in responding to people's questions. I believe that we received important input for the development of our program. As we look ahead to November 10, 1993 for the regulatory agency meeting and November 17, 1993 for our next public meeting, there is much work to do in order to be prepared. I have enclosed a copy of the attendance list and a typed copy of the questions and comments that I recorded at both meetings. Please add to the questions/comments list if you recorded any that I missed. Also enclosed is a copy of the City design team comments on the preliminary draft goals and objectives, policy issues, eligibilty requirements, regulatory requirements, and opportunities and constraints received by the City from October 6 to 8th. Generally we thought that the documents were incomplete and we will not pay any additional costs for revising these documents. We will need to see a complete draft with any sections not yet reviewed, including associated figures and tables. For issues that require a decision by the City, we request that you identify them as soon as possible using the following problem solving sequence: A. Issue statement (Problem Statement) B. Background C. Options (alternatives) D. Pros and cons of each option E. Recommendation. We are relying on your team of experts to provide us with a program that is easy to understand and that will work. This is new ground and your vision is needed to make it a success. Please keep me informed of any potential problems with meeting task completion dates so that we can work together to keep the project on schedule. If you have any questions, please call me at (206) 277-5547. Sincerely, f cfl-c" � Scott Woodbury, roject Manager Surface Water Utility H:DOCS:93-1039:SSW:ps CC: Ronald J. Straka Enclosures 200 Mill Avenue South - Renton, Washington 98055 THIS PAPER CONTAINS 50%RECYCLED MATERIAL,10%POST CONSUMER CITY OF RENTON WETLAND MITIGATION BANKING PROGRAM ' Prepared for CITY OF RENTON 200 Mill Avenue Renton, Washington 98055 Prepared by PARAMETRIX INC. 5808 Lake Washington Blvd. NE Kirkland, Washington 98033 �1 w W VO October 1993 1 TABLE OF CONTENTS Page EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii CHAPTER 1. GOALS AND OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 INTRODUCTION 1 1.2 MITIGATION PROGRAM OBJECTIVES . . . . . . . . . . . . . . . 1 CHAPTER 2. POLICY ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 CHAPTER 3. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 jTO BE COMPLETED APPENDICES tTO BE COMPLETED i drftmtig.pin i City of Renton - DRAFT 55-1779-07 October 6, 1993 LIST OF TABLES 1 TO BE COMPLETED 1 LIST OF FIGURES TO BE COMPLETED LIST OF MAPS ITO BE COMPLETED drftmtigpin ii City of Renton -DRAFT 55-1779-07 October 6, 1993 i i EXECUTIVE SUMMARY TO BE COMPLETED r i i 1 1 i t 1 drftmtigpin iii City of Renton - DRAFT 55-1779-07 October 6, 1993 CHAPTER 1. GOALS AND OBJECTIVES 1.1 INTRODUCTION The City of Renton��developing a wetland mitigation program and plan that will result in no net loss of wetlands. This program will primarily encompass land within the city limits, as well as land outside the city limits that may be annexed in the future. The City's overall1goal is to establish large contiguous wetlands on City property along or nearby Springbrook Creek in the Black River drainage basin. The primary goal in establishing these contiguous wetlands is to use these wetlands to offset impacts to lower quality wetlands by private and public development projects that occur within the same drainage basin. In fulfilling this goal it is the City's intent to balance community desires for economic development and � -zffnrdgblg-heusing with the responsibility to retain the City's remaining wetlands.l This will be ° accomplished by encouraging higher intensity development in areas already supported by infrastructure and encouraging lower intensity development in areas containing wetlands. The city will also encourage restoring disturbed and lower value wetlands and providing maximum Iprotection to higher value wetlands remaining in the City. The City has recently acquired two Iparcels of land totaling 45 acres for the purposes of establishing a mitigation program (Figure 1.2 MITIGATION PROGRAM OBJECTIVES Other objectives for the City's wetland program have been identified and are presented below: drftmtig.pin 1 City of Renton - DRAFT 55-1779-07 October 6, 1993 r To Achieve No Net Loss of Wetlands ' The City of Renton supports the concept of no net loss of wetland acreage, values, and functions by protecting high value wetlands, and requiring restoration of disturbed wetlands or creation of new wetlands to offset losses that are unavoidable (City of Renton Ordinance Number 4336, Chapter 22). In meeting the goal of no net loss of wetland resources, the City encourages the creation of wetlands that will be a higher category than the altered wetland. An additional component of the no net loss objective is to allow multiple or cooperative compensation for one project within the same drainage basin in order to best achieve the goal of no net loss. Finally, the City believes that establishing larger contiguous wetlands for the purposes of a mitigation ' banking program or offsite mitigation program will achieve the objective of no net loss by providing larger, consolidated, and higher quality wetlands rather than small, scattered, and low quality wetlands. To Define Eligibility Requirements for Use of the Mitigation Sites St f" Eligibility requirements for use of the two parcels will need to be based on the type and size of wetlands that may be subject to impacts from future development, the wetland functions and ( values, the required replacement ratios pursuant to the City's ordinance, compliance with sequencing and other provisions of the City's ordinance, off-site replacement feasibility, and ' location of the impacted wetland within the basin's landscape. Provide a 1:1 Replacement(1 Acre of Wetland Creation/Restoration for 1 Acre of Impacted Wetland) for 5.33 Acres of Impacted Category 3 Wetland (as Defined by the City's Ordinance Number 4346). The City of Renton and Glacier Park Company entered into an agreement in May 1992 whereby _..._ I Glacier Park transferred two parcels of land ( > ) to City ownership in exchange for development of six parcels that would require filling up4o- 1 acre of lower quality wetlands on jdrftmtig.pin 2 City of Renton - DRAFT 55-1779-07 October 6, 1993 ��ts PW�/!�►i D� �li7•ae f A L�4w� � t��►''"y � (D.`l ot Ae_ c1�1 y /I r ■r r� �■�r r r� err �r as �r r� r r rr � r r � � � s s J 3 14 each parcel. The City has assumed the responsibility of providing the compensatory mitigation 0•`�7 for these one acre fills and has an bligimplement the compensatory mitigation action. To Establish and Expand a Regional Wetland System Located Near and Adjacent to ' Springbrook Creek and Other Significant Wetlands The City of Renton currently owns several parcels of property that contain wetlands (Figure;...... The intent of the City is to retain the natural features of these parcels for the purposes of open Ispace and natural resource corridors. The wetlands on these parcels are currently providing some of the recognized functions of wetlands including flood storage, wildlife habitat, water quality ' improvement, and groundwater recharge. Restoring and creating additional wetlands within the two parcels considered in this mitigation program will add to the wetland resource base within the City, ' flood storage, and hydrologic value; consolidate wetland mitigation within the Green River valley to enhance wildlife habitat; provide additional ' connections with other wetland parcels under City ownership; and provide passive recreation and educational opportunities through coordination with the City's parks and open space program. Retain Natural Features The community can enhance the natural diversity of Renton by protecting a variety of wetlands, restoring a variety of wetland types, managing them as a connected system, and by linking them ' together. Add to Wetland Resource Base The City desires to use the mitigation program and mitigation banking concept as an opportunity to reverse the trend of wetland losses and begin a positive trend toward wetland gains by restoring some of the historic wetland systems in the Black River drainage. drftmtig.pin 3 City of Renton - DRAFT 55-1779-07 October 6, 1993 v Water Quality Improvements ' Constructed wetlands and wetland improvements will be used as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways in Renton. In some instances, wetlands will be restored by providing more water from Springbrook Creek to the sites. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live, work and visit Renton. While the wetlands to be established on the mitigation sites have multiple values one of their primary uses will be ' for improving the quality of downstream aquatic environments. Improved Flood Control da•.�!r�taT ate( �e¢L` S� w w. 44- B establishing a direct connection o miti ation site 1:VJ__G y g g Springbrook Creek, protecting existing LXewh-''� wetlands, and restoring wetlands on both mitigation sites, additional flood storage capacity can ' be added in Renton. This will reduce downstream impacts of storm runoff originating in the urban area. These flood storage improvements can often provide multiple benefits, such as ' wildlife habitat and recreation. I„� 1 Consolidate Wetland Mitigation The City of Renton's mitigation program proposes to utilize the wetland mitigation bank concept as the primary means for implementing the mitigation program. With this approach, mitigation efforts are planned where the most suitable sites are identified (Mitigation Sites 1 and 2), acquired and restored in advance of wetland impact. The consolidated wetland mitigation approach also provides opportunities for achieving the wetland mitigation program goals and objectives when on-site options are not feasible. The mitigation banking concept benefits both the community and users of the bank as well as the natural resources that use and/or depend on wetlae=tails tems. The bank system utilizes the mitigation requirements for individual users where e of compensation are preplanned, constructed, and maintained by the City. To satisfy drftmtig.pin 4 *-'s City of Renton - DRAFT 55-1779-07 October 6, 1993 r ' individual impact requirements, users could either buy mitigation credits from the bank, or could be charged a fee to pay into the bank that would be used by `':`:i VA to ........... ' ...... : ..;::.::::: ' undertake the mitigation action. �� Enhance Wildlife Habitat and Habitat Corridors ��.��d g � /tfo10 ' By protecting and restoring a variety of wetland types, and by buffering natural areas from the impacts of nearby development, a diversity of habitats will be established; that diversity will ' benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding existing natural systems and restoring habitats in areas that have been damaged by human activities insures better survival of wildlife and wildlife viewing opportunities. The concept of habitat corridors also achieves the goal of enhanced wildlife habitat. Recreation, Education. and Research Planned trails, b , wildlife observation points and cleaner water within a diverse system of wetland types could provide numerous opportunities for public enjoyment of Renton environments. The wetland environment in Renton will become a favorite place to recreate and learn, particularly if utilized by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington, Lake Washington Community College, South Seattle Community College, Renton wetlands could be the subject of further study by interested wetland research scientists over the coming decades. i ' drftmtig.pin 5 City of Renton - DRAFT 55-1779-07 October 6, 1993 1 w (t -t L L S e/4..C,.V 44 )40,0 1 1 1 1 i 1 CHAPTER 2. POLICY ISSUES l Three policy issues were identified by the City and project team that require discussion and resolution and are identified and discussed below. ' Should the Mitigation Sites be Used for City-sponsored Projects? An area of particular concern to the city is developing criteria for use of the mitigation bank that will allow expanded opportunities to compensate for city-sponsored projects. As currently conceived, the mitigation bank would limit eligible projects to those with areal impacts less than one acre in isolated wetlands and wetlands above the headwaters (thereby eliminating the Corps of Engineers Section 404 permit process and the Washington Department of Ecology's Pre- Discharge Notification Nationwide Process), and to projects that do not require a Shoreline rSubstantial Development Permit (thereby eliminating Washington Department of Ecology review through the State Shoreline Management Act). We understand that there may be some cases where the city needs or desires to utilize the mitigation bank for projects requiring one of these permit reviews. Yam` Under the current ordinance, a wide range of city-sponsored activities can occur in wetlands without obtaining a special permit. These activities include: • Activities affecting a single, hydrologically isolated Category 1 and 2 wetland less than 2,200 sq ft within a property boundary are exempt (4-324.C.1). c-,-" OF �a^Ar Cock_ • Activities affecting hydrologically isolated Category 3 wetlands less than 5000 sq ft within a property boundary are exempt (4-32-4.C.2). C,,�� drftmtig.pin 6 City of Renton - DRAFT 55-1779-07 October 6, 1993 1 1 1 1 1 1 1 1 1 1 1 1 1 1 t ' • Normal and routine maintenance and repair of existing facilities where no alteration of the wetland or additional fill materials will be placed (4-32-4.A.4). The area must be 1 restored to original conditions. • Normal and routine maintenance and repair with minimum placement of fill to bring facility up to established safety standards (4-32-4.A.5). Impact must be minimized and area restored. • New surface water discharges to Category 1, 2 and 3 w tlands where discharge meets g rY g Storm and Surface Water Drainage Ordinance (Chapter 22) and will not result in significant changes in water temperature or chemical characteristics, and any changes in hydrology that would result in greater wetland function and value (4-3�4.A.9). • Regional stormwater management facilities designed consistent with Ecology's Wetlands ' and Stormwater Management Guidelines (4-32-4.A.12). ' • Enlargement of facilities beyond existing needs provided footprint does not increase more than 10% within the wetland or its buffer (4-32-4.C.6). • Emergency activities (4-32-4.D). As outlined above, the Wetlands Management Ordinance (No. 4346)allows outright a wide range 'of city-sponsored activities whose impacts could be compensated for through the use of the 1 mitigation bank. However, the ordinance does not make special provisions to allow for impacts above and beyond those identified above solely because a project is city-sponsored. As the mitigation bank is developed and codified, the City could amend Ordinance No. 4346, Section 4-32-6.G-Cooperative Wetlands Basin Planning, Mitigation Banks, or Special Area Management iPlans to specify additional parameters for city use of the bank to encompass situations that do not conform with the basic "small project" concept of the bank. drftmtig.pin 7 City of Renton - DRAFT 55-1779-07 October 6, 1993 owe �,J��-1�.. �v �1� �a- LiA l LL . Zham- f3 k- dlll�t- h-S k -T��v, dL.,.,c.� C J� �10�'1.� fcL�y✓L� �j(ns-J(OJ( �.,1. �'�Q--�Y (V/ r G 1�5s G 1. o A-c ' Should the Mitigation Sites be Used for Impacts to Category 2 Wetlands, or Only for Projects Impacting Category 3 Wetlands? In early conversations about the structure of the mitigation bank, the general agreement seemed ' to be that only projects affecting Category 3 wetlands should be eligible to use the bank. The general reasoning for this idea was that these wetlands would tend to be the smallest and lowest ' value wetlands, and that any permitting decisions would largely be a City responsibility. The primary exception to this concept would occur for Category 3 wetlands between one and ten acres ' in size, where impacts over an acre would require Section 404 or Ecology review. However, our review of the Wetlands Management Ordinance ~tifia :az �ztet ,;;:Indicates ' tjiat some Category 2 wetlands could meet the "small project" concept of the bank (e.g., no Section 404 or Shoreline review) and therefore be eligible to use the bank unless specifically precluded from the program. In fact, because the ordinance does not specifically state that Category 1 wetlands cannot be altered, it is conceivable that impacts to a Category 1 wetland could also meet the "small project" concept. In addition, it is conceivable that city-sponsored projects may impact Category 2 wetlands. One of the goals for the mitigation bank is to provide ecologically sound opportunities for achieving wetland compensation objectives when on-site options are not feasible. As criteria for eligibility requirements are developed, specific requirements for each category of wetland should be considered. Criteria should, in part, be ecologically based so that off-site compensation for impacts to Category 1 wetlands, for example, would be allowed because of the "value added" effect of habitat creation as part of a larger planned system. This will be a difficult distinction ' to articulate, but in an ecological context it is an important distinction that will help screen the most appropriate and important sites for bank eligibility. drftmtig.pin 8 City of Renton - DRAFT 55-1779-07 October 6, 1993 1 1 1 1 1 P.aS e-, Cc ems iz i 1 Should the City be Solely Responsible for Managing the Mitigation Program and Mitigation Sites? When the Renton mitigation bank was conceived, federal wetland mitigation policy acknowledged ' mitigation banking as a viable strategy. Recent guidance from the Corps and EPA, dated August 23, 1993, outlines requirements for establishment and use of wetland mitigation banks in the Clean Water Act Section 404 regulatory program. Two key elements of the guidance pertaining to mitigation sequencing and implementation agreements are particularly challenging for local mitigation banking programs. These two elements essentially require that: (1) local mitigation _decisions adhere to the federal requirements for sequencing (i.e., avoidance, minimization, ' compe ion)- 'n analysis of practicable alternatives; d (2) that all relevant resource agencies agree in writing as to the purpose, implementation, use and maintenance of the ' mitigation bank. City staff recognize that these program elements are desirable for maximizing resource protection and minimizing overlapping and/or contradictory regulatory requirements; ' however, gaining an agreement between all relevant resource agencies in a short time frame would be difficult. With the City's near-term requirement to provide compensation for the Glacier Park properties, it was agreed that the bank should be established for projects that only ow;z require a City permit decision, and that the bank should be managed by the City. This current effort will allow the City to develop a mitigation banking "demonstration" project that is relatively simple to implement because it will not require the commitment of time necessary to gain concurrence among several resource agencies.CDuring the course of this project, the future potential for a more broad-based mitigation bank that is also usable for projects requiring Section 404 and Shoreline Substantial Development permits will be evaluated. of drftmtig.pin 9 City of Renton - DRAFT 55-1779-07 October 6, 1993 �j � cr/c— s✓' `��'- 1�ter— Cc i CHAPTER 3. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANK In general, eligibility criteria for use of the mitigation banking program are based on regulatory requirements and ecological consideration. The eligibility criteria for the City's program would determine which wetlands in the Black River drainage basin may be altered and subsequently compensated for at a mitigation banking site. A draft list of eligibility criteria are presented below and are shown in Figure :..,.... Does the Proposed Project Comply with City rdinance Number 43461 Projects that have unavoidable and necessary impacts would be considered for incorporation in the wetland mitigation banking program provided that they demonstrate compliance with all standards of the City's ordinance. For example, use of the mitigation bank to compensate for twetland impacts would be tied to the mitigation policy of sequential mitigation actions including avoiding adverse impacts, taking affirmative measures to minimize impacts, and compensation ' for impacts. Mitigation banking is basically a form of compensatory mitigation. In addition, the mitigation should be comprised of higher category habitat than the altered habitat, so that similar or greater functions and values in the drainage basis are achieved [see section 4-32-6 (A)(2)], and ' the City's standards for wetland creation and/or restoration are met. ' Is the Proposed Project Located Within the Black River Drainage Basin? ' The altered wetland must be located within the Black River drainage basin, including the Green River valley. drftmtig.pin 10 City of Renton - DRAFT 55-1779-07 October 6, 1993 What is the Size and Category of the Wetland That May be Affected? Wetlands classified as Category 1, 2, or 3 wetlands by the City that may be altered consistent with Ordinance 4346 are potentially eligible for use of the mitigation banking sites. However, the altered wetland or altered portion of a wetland must be less than one acre, and either isolated or above the head waters. Written documentation from the U.S. Army Corps of Engineers on the jurisdictional status (i.e., isolated, above the head waters) of the wetland to be altered would be required. In addition, the altered wetland cannot be considered a shoreline of the state. Is On-site Mitigation Feasible? Off-site Versus On-site Mitigation Feasibile? The wetland to be altered would be considered eligible for use of the mitigation banking program ' when: ' On-site mitigation is infeasible (e.g., would eny reason use of the property, not practical due to problems with hydrology, soils, or other factors, surrounding land uses) On-site mitigation is undesirable from a wetlands resource and landscape perspective (Le, when on-site mitigation would result in wetlands or aquatic habitats with minimal or potentially unrestorable functional value). s.►-/ :::P�'v` ' On-site mitigation will not best meet identified regional wetland preservation goals (e.g., replacement of historically diminished wetland types). • On-site mitigation cannot replace communities and functions of the altered wetland. The mitigation banking sites can replace the range of ctions and�valueas those provided by the wetland or aquatic habitat that will be impacted. drftmtig.pin 11 City of Renton - DRAFT 55-1779-07 October 6, 1993 1 1 1 MITIGATION BANKING No DOES THE PROJECT COMPLY WITH ' SOULD NOT BE 4 CITY ORDINANCE NUMBER 4346? CONSIDERED Yes No IS THE PROPOSED PROJECT LOCATED ' WITHIN THE BLACK RIVER DRAINAGE BASIN Yes 1 No IS THE IMPACTED WETLAND ' LESS THAN ONE ACRE, AND ISOLATED OR ABOVE THE HEADWATERS? r Yes Yes IS ON-SITE MITIGATION FEASIBLE? No ELIGIBLE FOR MITIGATION BANKING PROGRAM 1 r 1 r r r rDetermining Eligibility for Use of Mitigation Program 1 OC 1-15-y3 t K l 14: 41 PAKAM 1 K 1 X h AX NO, 206 889 8808 P, 02/05 Soil test pit 5 was excavated in an upland area and had a similar profile to test pit 4. Fill occurred from the surface to 2 ft 8 inches. The historic A horizon was observed below the fill and extended 12 inches below the fill, Clay was the dominant soil below the historic A horizon, Black sand was observed at 10 ft 4 inches. The sides of the soil pit were glistening and seepage was evident at 8 ft. 5.3.2.3 Hydrology 5 .J—e The source of hydrology for the existing wetlands is primarily precipitation. Wetlands on this site lack an obvious inlet or outlet source. Saturation to the surface and inundation to a depth of 1 inch were observed by Jones and Stokes (1993) in the emergent wetland areas. On the day of the site visit in July 1993 inundation and saturation were not observed in the forested portions; however, wetland hydrology was assumed based on depressional topography, soil characteristics, and bare ground. The functional values associated with these wetlands were rated as low by Jones and Stokes (1993) and David Evans and Associates (199) due to the size of the wetlands, lack of structural and community diversity, and an isolated and disturbed nature. The wetlands are extremely limited in providing sediment trapping, food chain support, and groundwater recharge and discharge. The wetlands and depressional topography provide some flood storage and wildlife habitat. The limited young forested and shrub canopy layers provide some cover for small mammals and birds, 5.3.3 -Opportunities Using the results of the analysis of existing information and the field investigation the opportunities and constraints associated with establishing wetlands on the mitigation sites was prepared and are presented below. The natural ecosystems in the valley have been severely altered through the years by development. Reestablishing wetlands on the mitigation sites provides an excellent opportunity for the City to gain wetland acreage in a floodplain area where the added physical functions of stormwater attenuation and biofiltration will achieve the highest value. The mitigation program is a great opportunity for the City t,) demonstrate that wetland mitigation is feasible and to assist in furthering the concept and technical and administrative approaches of mitigation�g. The fact that the City, as a local sponsor, is committed to establishing a mitigation- ng program that is based on public and private partnerships indicates that the City is on the cutting edge of demonstrating the feasibility of mitigatiod�� '� R "''' �,:` The mitigation program is also an excellent opportunity to develop the framework form` ` in the currently conceived form of a demonstration project that is relatively small-scale (i.e., can be developed without entire complement of agencies involved in negotiating and implementation process). drffm 55-17 i9-07g.pIn 21 City of Renton - DR4FT SS-1779-0 i October 14, 1993 UUI-15-J� MI 14;41 rHKHnt1K1X hAX NO, 2A 88U bbUb F, U3/05 Much of the existing wetland on the mitigation sites is of low quality (e.g., young, alder with poorly developed understory, no surface expression of hydrology, encroached on by dense blackberry thickets). Mitigation construction could include enhancement of existing wetlands to improve overall character and quality of system. Vr �+ 5.3-3.1 Opportunities in Mitigation Site 1 t Mitigation Site 1 is adjacent to large, high value wetla nds grids (Category 1 wetlands based on the City s rating system) which will not be filled or alte:red in the future. This provides the opportunity to protect created wetlands on Mitigation Site 1 and the possibility of increased 3 ` functional values (i.e., providing connections between werland systems owned by the City for the purpose of providing habitat corridors and open space for passive uses) within and between the neighboring wetland systems. �h Mitigation Site 1 provides an opportunity to increase the acreage capacity of flood storage, This site may provide storage opportunities for localized runoff from adjacent and upstream developments as well as backwater storage from Springbrook Creek. A recent b �' proposal Y N to re-align Springbrook Creek would route normal flows from SW 43rd Street north past and along the west side of Site 1, then flow east toward Springbrook Creek. It would also route high flows along the existing Springbrook Creek channel between SW 43rd Street and SW 27th St reet. Incorporating a design feature that would route the water through Mitigation Site 1 before 3 flowing east to� Springbrook Creek would positively impact' Y p Site 1 by providing greater hydrologic support for the entire wetland system as well as provide the hydrology necessary to support hydrophytic vegetation reestablished in the upland areas of the mitigation site. Mitigation Site 1 provides an excellent opportunity for greatly enhancing the wildlife habitat, both aquatic and terrestrial, at this site because of its size and greater isolation from urban development. The City of Renton recreation plans (a ?< show trails in close proximity to Mitigation Site 1. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling?, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban stormwater quality, etc., and could be offered by interpretive signage and printed materials. 5.3.3.2 Opportunities in Mitigation Site 2 �•• cis tfr sa.,c...� �..�vvn� Mitigation Site 2 is adjacent to a historic natural ri arian feature at has since been charineliz d. The mitigation site's proximity to ng rook Creek offers an opportunity to provide wildlife linkages to other wetlands and open space areas as well as downstream benefits to fish and wildlife. Mitigation Site 2 offers an excellent and direct opportunity to increase flood storage drftmtig.pin 22 City of Renton -DRAFT SS-1779-07 October 14, 1993 �ivi a., v.J i ia a-c �� uuui.iuin I fill 111.). LUV UUV UUUU I . U`i/ UU capacity because of its proximity to ippringbrook Creek. The recent proposal mentioned above would not appear to significantly affect opportunities to also re-align a portion of Springbrook Creek through Mitigation Site 2. Diversion of high flows into this mitigation site would provide increased water quality improvement for downstream receiving waters and detrital input to benefit neighboring and downstream aquatic organisms. An Excellent opportunity exists for greatly enhancing the wildlife habitat, both aquatic and terrestrial, at this site because of its proximity to Springbrook Creek. The City of Renton recreation plans a.•s _e. g P ( t ) show trails along Mitigation Site 2. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban stormwater quality, etc. and could be offered by interpretive signage and printed materials. An opportunity exists to keep some meadow areas relatively dry for small mammals as food source for raptors, which use the area. However, this drier habitat could be wet meadow, thereby meeting the goals for wetland creation. While there are still substantial areas of dry field/small mammal habitat in the area, providing this type of habitat along with other types of habitat increases the overall diversity and features inherent in a higher quality wetland system 5.3.4 Constraints The City of Renton's wetland ordinance does not recognize enhancement as an acceptable form of compensatory mitigation. There are approximately 25 acres of additional area that could be enhanced and used for mitigataonIMAg if the ordinance was modified in the future. The available information on existing hydrology may not be adequate to develop site designs with the level of specificity required to prepare a bid package. No groundwater monitoring has been done on either site to establish seasonal fluctuations which would aid in the design of created wetlands. Ideally, the level of ground water should be measured on both sites for at least 1 year, 1 „V Ground water wells constructed of PVC pipe could be installed and monitored over the winter V and spring, This additional information would allow the site designs to be modified to reflect the changes in groundwater hydrology on both sites. Information on the level of groundwater relative to the levels in Springbrook Creek have been eva::uated. Perhaps the most challenging current constrain is the depth to ground water and the available hydrology to reestablish wetlands on the mitigation sites. There is little available on-site water to support created wetlands. Wetlands on both sites appear to have developed as a result of sur__fa��vsrater accumulation, in slight depressional areas where, over time, finer sediments have accumulated and reduced soil permeability. Hydrologic support for Mitigation Site 1 appears to be from. local precipitation, and possibly from a drainage ditch that extends along the western and northerly property boundaries, Consequently, wetland hydrologic support is limited mostly to precipitation. Hydrologic support for Mitigation Site 2 appears to also be from local precipitation drftmag.pin 23 City of Renton - DRAFT 55-1779-07 October 14, 1993 • � �� ••• •� ••••••••- ••••• i •i 1 v. �v v v v v v v v v 1 V J/ V J and Springbrook Creek, that extends along the easterly and southerly rope bound uring extreme storm and flooding events. Wetlands on both sates appear to have developed a pa h d water table that is not hydrologically related to groundwater. Consequently,hydrologic support is limited to local precipitation. current wetland 0- i AI**, (�'�h There is a potential that the dil ng district may place restrictions on reconstructing dikes or removing a portion of the dike adjacent to Mitigation Site 2. The possibility of removing or altering a portion of the dike will need to be discussed with the diking district to develop the site plan for Mitigation Site 2. Because of the depth to groundwater observed on the sites in July 1993, and the fact that filling of both sites has placed ground elevations well above the original floodplain elevations, the costs to excavate and remove soils will be high. In addition, these conditions will make it difficult to establish a hydrologic connection between created wetlands on Mitigation Site 2 and Springbrook Creek. Thus, a balanced cut and fill scenario is unlikely given the depth to which excavation must occur if created wetlands are to utilize groundwater hydrology. Export of significant amounts of material is likely. Although the costs for excavation will be relatively high, once hydrology is obtained, wetland creation success probability increases with correspondingly lower landscape costs (i.e., plant material costs), Urban development is in close proximity to both sites. Springbrook Creek, adjacent to Mitigation Site 2, is an engineered ditch and becomes isolated from other wetland and open sp ace areas with development of adjacent property to the north. Site 1 is relatively more isolated from urban development, and is unlikely to have a major thoroughfare along one of its boundaries (once construction of the gravity sewer system is complete). Nevertheless, this site has adjacent commercial development along its southern boundary, acid further development in this area is likely to occur. The soil seed bank on both sites probably does not contain some of the important plant species (e.g., rushes, sedges, bulrushes, bur-reed, cattail, water parsley, water lily, etc) which might be used in the mitigationg wetlands. Existing plant communities express what is held in the seed bank (i.e., black cottonwood, red alder, salmonben reed can ` blackberry). YI arygrass, and Himalayan Little wetland soils (e.g., peats or muck) are available on the sites for use in construction of new wetlands. An appropriate planting medium and topsoil may need to be imported to the sites. This raises an issue about the balance between costs and benefits of creating wetlands on the upland portions of the mitigation sites. At what economic level does it become infeasible to do this type of development and implementation and how is that balanced with the intrinsic issues like habitat value? Ultimately, there must be an economic incentive to proceed -- it is governed b Y markets w i which operate even to the environmental en arena :�:11.. j� ¢• ;�n, ;..2:::R:k::a:�„.,,..._.......:.R _..:ki'6,�f:Q:lu:R.<yi�R.�;r'. ,, ..�'R7ss�',' n ��.h. '.l{� :F'ce°'1.,�:. •:r :a: 5..:6A+ .>: kh:q:. :aR R.a k.d: R.a:a:.R1'oa :R:..:...: ..<......r:� �,\.<..e.,M.A..�.,:•/✓::':e:FL.LS;/ f�':����kh„ q����'��?'� ,'�a .'Mox:�: �H .Q:e .x.R.RI:. ,y:A:R.}ie�<. fl:i drfi -PIn 55-17 i 9-07 24 City of Renton - DRAFT SS-1779-07 October 14, 1993 Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd.N.E. Kirkland,WA 98033-7350 206-822-8880•Fax:206-889-8808 Mr. Scott Woodbury October 6, 1993 City of Renton 55-1779-07 200 Mill Avenue South Renton, Washington 98055 Dear Scott: Enclosed for the City's review and comments are draft copies of the goals and objectives for the wetland mitigation program, the policy issues for the City's consideration, and the draft eligibility requirements. The draft regulatory requirements and the conditions assessment along with the electronic version of everything are being sent to you under separate cover. I would appreciate it if the City would review these from the perspective of the type of audience that will receive this material. Please note that the draft cover includes the City's logo. I was thinking that a picture could be used along with the logo for the cover of the overall mitigation program document. Does the City have a photograph that they would like to use for the cover? If so, please provide me with one at your convenience. Now v{b�,+ ��c .,r--- ob +w G.�p•,..� ��.,. Also, please note that there are only four draft eligibility requirements. In part this is because we are trying to develop a program where project proponents will not get the perception that they are being burdened with another layer of the regulatory process. There are two other criteria we would like to consider, but inclusion of them requires a discussion with the City. The additional criteria we would like to consider relate to whether or not the City plans on doing all of the mitigation construction, the timing of completion of the mitigation, and assurances that there will be enough money to implement the mitigation. These are identified primarily in the form of questions below: -I ,. G '"�'"" Will the City actually do the mitigation construction on both sites? If so, is the City a L�w 14 willing to collect a fee from a project proponent and wait until enough money is v qli haNv f4*,k G accumulated before implementing the mitigation construction? If the answer to the second question is yes, then the development project could not occur until the City had enough of � � funds to complete the mitigation construction of an entire site or a portion of a mitigation site (i.e., phased approach). Would the project proponent be able to undertake the development activity prior to the T L,, D,p City completing the mitigation action or would the project proponent also have to wait oef, ri-,,y,q, until the mitigation is constructed? Instead does the City want to assess itself now and ro � ► .�. l.�s t (�-- 1�w,- t,,�}I.. �ra S s Ccr�y s -rA— �� Printed on Recycled Paper , Mr. Scott Woodbury City of Renton October 6, 1993 Page 2 contribute a proportion of City revenue and collect a late comer fee to guarantee that money will be available to do the mitigation? Will a project proponent be allowed to construct the mitigation in discrete portions of the mitigation sites as long as the mitigation is done in advance of the project impact, the Ce^3-14- . mitigation action is feasible, and it is consistent with the overall mitigation program? If so, how can the City be assured that there are discrete areas of the mitigation sites where the proposed mitigation will be feasible and how can the City be assured that the mitigation will actually be completed (e.g., by not issuing a permit until the mitigation work is compete and requiring a monitoring/maintenance bond)? I look forward to your comments and suggestions. You can send comments to me or wait until our meeting October 18 to go over them. Please call me at 822-8880 if you have any questions or require additional information. Sincerely, .haQt Tracey McKenzie TPM/sh enclosures r r CITY OF RENTON WETLAND MITIGATION BANKING PROGRAM Prepared for CITY OF RENTON 200 Mill Avenue Renton, Washington 98055 Prepared by rPARAMETRIX, INC. 5808 Lake Washington Blvd. NE Kirkland, Washington 98033 October 1993 1 TABLE OF CONTENTS rPage 1 EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii l/erRC)D U CR 0IU g,Ac4c(z-A6 "Nb CHAPTER 1. GOALS AND OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 INTRODUCTION Cam,ate'. . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 MITIGATION PROGRAM OBJECTIVES . . . . . . . . . . . . . . . 1 CHAPTER 2. POLICY ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 CHAPTER 3. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION rBANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 TO BE COMPLETED 1 r APPENDICES W�L-�9 v/LP/w�A McE ' TO BE COMPLETED T0 r r r drftmtigpin i City of Renton -DRAFT 55-1779-07 October 6, 1993 1 LIST OF TABLES r TO BE COMPLETED r r LIST OF FIGURES �r TO BE COMPLETED r r LIST OF MAPS TO BE COMPLETED i r r drftmtigpin ii City of Renton -DRAFT 55-1779-07 October 6, 1993 r r EXECUTIVE SUMMARY TO BE COMPLETED i 1 t r r drftmtigpin iii City of Renton - DRAFT 55-1779-07 October 6, 1993 CHAPTER 1. GOALS AND OBJECTIVES ,AWt' n50f rPAS Gurwgl� . 1 1.1 INTRODUCTION 6,oP<.-S s1s�1 1 Pr°)"°t� G ��02 S The City of Renton is developing a wetland mitigation program and plan that will rew&4h no l< *r wa risFPcl q ,l net loss of wetlands. This program will primarily encompass land within the.city limits, as well ' as land outside the city limits that may be annexed in the future. ii G 4,> e 6, rlc.ArP !ie /,rr�, v Uv ui'6a.7 (f�'o�✓UL/ �s/'Caf o/' y��f a.-� v/'/N�/i/•GsN��,' The City's overall goab,9 to establish large contiguous wetlands on City property along or nearby 1 Springbrook Creek in the Black River drainage basin. The grimary-goal4n establishing these contiguous wetlandse-use these wetlands to offset impacts to lower quality wetlands by 1 private and public development projects that occur within the same drainage basin. In fulfilling -fhcSe 1hi&,goal`it is the City's intent to balance community desires for economic development and affordable housing with the responsibi-l� to retain t I he City's remaining wetlands. This will 1c��,,„ accomplished-by encouragin&higher intens�iV development in areas already supported by infrastructure and-encouraging 1 ry deveiopme +� � n'g wetlands. The city will also e 1 ' g d11 swrbed and-lower--value wetlands-and providihg maximum protection to higher-glue wetlands remaming-in the Ci The City has recently acquirDtwoparcels of land totaling 45 acres for the purposes of establishing a mitigation program ( l GP/h'�PPR(i WI C�°.ALA /N >J' L1S9TI (- Of- W/ 6-1cPL11/nATIQW [ oLtzw),-� ro 1.2 MITIGATION PROGRAM OBJECTIVES ' (ke,6"AWrz1NL- "-Wo /V�-�;,, TO ff--^01e 083're-o s r44T F•A,41 l �f M f C>6�)'C-s. Wither_objectives for the City's wetland program have been identified and are presented below: /. . P P1 PFn,�7Fi 7 uE {-r,;;;, ; f �-0rlor�s,.• :Aq V,6 1IA�wwfs of . (.,e4 Tq ,wCrt,,Q-.✓or � ,,.c .►P h 0dCj1JA%& rq f YVNUr/uwL /ki✓D ✓A4gjI T F/c rJH Wt r LAeJO r. 2 . mc(& sE ,, rl4f P��Pk 't ow ,4.�.'r ,G�g��,,r y 7, (Jse 7'14 MNPW , /rooEM�r ^)/f to 5"c lAv /ry c-1 c fJY 50 L)('P'7 E I/J ot.4 °�` 7 4w L aG�71 vie J /) KF' (�►)" r/a drflmtig.pin 1 Wei of Renton - D AA FT 55-1779-07 �"'y Sc,�-7rr� ,.W+�7�/-�n�. 5" PG 3 , October 6, 1993 y /AY1%kA4; T06 61uAur rj itFE P 70 C.m✓T ort+r. A-,r» i'v'►p c,€,,,c-T 1�11FVT pLwS � r To Achieve No Net Loss of Wetlands 7lis 15' The City of Renton supports the concept of no net loss of wetland acreage, values, and functions by protecting high value wetlands, and requiring restoration of disturbed wetlands or creation of new wetlands to offset losses that are unavoidable (City of Renton Ordinance Number 4336, 32 Chapter 22). In meeting the goal of no net loss of wetland resources, the City encourages the creation of wetlands that will be a higher category than the altered wetland. An additional component of the no net loss objective is to allow multiple or cooperative compensation for one project within the same drainage basin in order to best achieve the goal of no net loss. Finally, ' the City believes that establishing larger contiguous wetlands for the purposes of a mitigation banking program or off-site mitigation program will achieve the objective of no net loss by providing larger, consolidated, and higher quality wetlands rather than small, scattered, and low quality wetlands. To Define Eligibility Requirements for Use of the Mitigation Sites Eligibility requirements for use of the two parcels will need to be based on the type and size of wetlands that may be subject to impacts from future developme the wetland functions and 1 values, the required replacement ratios pursuant to the City's ordinance, compliance with sequencing and other provisions of the City's ordinance, off-site replacement feasibility, and location of the impacted wetland within the basin's landscape. f fEft�N �l i�rgrLrT`t CMA,TEA. U(L SC OW Provide a 1:1 Replacement (1 Acre of Wetland Creation/Restoration for 1 Acre of Impacted Wetland) for 5.33 Acres of Impacted Category 3 Wetland (as Defined by the City's ' Ordinance Number 4346). The City of Renton and Glacier Park Company entered into an agreement in May 1992 whereby ....................... Glacier Park transferred two parcels of land ( . to City ownership in exchange for development of six parc4thai""quiFe--filling up to 1 acre/bf lower quality wetlands on (+ �� A1660 i o Carves GrIa w T y RT drftmtig.pin 2 TH1s /WEAN; 5,3.3 City of Renton - DRAFT 55-1779-07 ACKS No i 61 October 6, 1993 I�kF�lru'.F �J�sroti.y Sf r+rlrw 1 SiX stpw,a& f AIGgS each parcel. The City has assumed the responsibility of providing the compensatory mitigation for these one acre fills and has an obligation to implement the compensatory mitigation action. To Establish and Expand a Regional Wetland System Located Near and Adjacent to tyts Springbrook Creek and Other Significant Wetlands LO a c,.l, /^i�u1M 1�7b GOAo A,0 The City of Renton currently owns several parcels of property that contain wetlands (Figure: ). The intent of the City is to retain the natural features of these parcels for the purposes of open ' space and natural resource corridors. The wetlands on these parcels are currently providing some of the recognized functions of wetlands including flood storage, wildlife habitat, water quality improvement, and groundwater recharge. Restoring and creating additional wetlands within the two parcels considered in this mitigation program will add to thedwetland resource base within 1 the City, improve stormwater control, flood storage, and e; consolidate wetland mitigation within the Green River valley S enhance wildlife habitat; provide additional connections with other wetland parcels under City ownership; and provide passive recreation and educational opportunities through coordination with the City's parks and open space program. r 7k /N r y 1 r sd�10'wi Retain Natural Features Mil' -,Pf4Rtc-q As Go.At -(Ai-5 !vo' ogJfctrjvk . �,p �5 The community can enhance the natural diversity of Renton by protecting a variety of wetlands, restoring a variety of wetland types, managing them as a connected system, and by linking them together. Add to Wetland Resource Base /v�(,EpPlwPkl/+�r� finno � �,� 06J i t'i vk WGIiLp 8k ST(Liuf� Td i„x�FiRrf fc.Ncr�uw B9 B/wvrniti6 usi�.c v+,�,cE a/f✓ w^hoc FlN6r/�T oR ';--(i.vg/rNt?v8 /,vt�/GtAFn Hy0/to�+ShroD• /nclF,4S,(Q �LhNf Q�v nSirr, r-U' The City desires to use the mitigation program and mitigation banking concept as an opS 5or"�urn' '` (JxrXd(. to reverse the trend of wetland losses and begin a positive trend toward wetland gains by restoring some of the historic wetland systems in the Black River drainage. drftmtig.pin 3 City of Renton - DRAFT 55-1779-07 October 6, 1993 i, PXdL/10 . 5-C-AL16. Pry„, Ar (y,* -r,-16. C.o.usTPJJtT Rrf ONk T/^-vE . /Acwaot, AT (x-f 'Tl,e4 . ir%Rl&-TA1,j AT o^T. 7-1.+.�F. 2. L4E - 14,A-7N6n/,+1V P�4 /iAw C.owsifTdM . Water Quality Improvements ✓ .� UB� /y !�c Constructed wetlands and wetland improvements will be used as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways in Renton. In m�� some instances, wetlands wild'be restored by providing more water from Springbrook Creek to the sites. The result will be cleaner surface waters, improved aquatic habitats, and a more 1 pleasant water-oriented experience for those who live,work and visit Renton. While the wetlands to be established on the mitigation sites have multiple values one of their primary uses will be for improving the quality of downstream aquatic environments. 1 Improved Flood Control ' By establishing a direct connection of mitigation site 2 to Springbrook Creek, protecting existing wetlands, and restoring wetlands on both mitigation sites, additional flood storage capacity can be added in Renton. This will reduce downstream impacts of storm runoff originating in the urban area. These flood storage improvements can often provide multiple benefits, such as wildlife habitat and recreation. ImW ddoy -6�4;;y �0S5//3tfr p&6/ov,%L, /yE� bi✓ (J5,6D A Mer16,*-t4m.l P-Vk tj--rEns>P" 0IfV4-(__00rfn Consolidate Wetland Mitigation /Ocf w6IU"V) 6 ,r,,k ,, ff Gvn+S r(wc ,q u- 1 a Aro��I U�d 1 The City of Renton's mitigation program proposes to utili the wetland mitigation bank concept as the primary means for implementing the mitigation rogram. With this approach, mitigation efforts are planned where the most suitable sites e identified (Mitigation Sites 1 and 2), acquired and restored in advance of wetland imp ct. The consolidated wetland mitigation approach also provides opportunities for achieving the wetland mitt program goals and objectives when on-site options are not feasible. The mitigation banking concept benefits both the community and users of the bank as well as the natural resources that use and/or depend on wetland systems. The bank system utilizes the mitigation requirements for individual users where the details of compensation are preplanned, constructed, and maintained by the City. To satisfy �F drftmtig.pin �� '^� ¢0 4 CeivFujt,v& City of Renton - DRAFT 55-1779-07 d�♦��• October 6, 1993 individual impact requirements, users could either buy mitigation credits from the bank, or could ■ be charged a fee to pay into the bank that would be used b # €ati to ............................................ undertake the mitigation action. 7Nis is Nor °+ a4rt r `- ' l Enhance Wildlife Habitat and Habitat Comctors r our 6� By protecting and restoring a variety of wetland types, and by buffering natural areas from the ' impacts of nearby development, a diversity of habitats will be established; that diversity will 1 benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding existing natural systems and restoring habitats in areas that have been damaged by human activities insures better survival of wildlife and wildlife viewing opportunities. The concept of habitat corridors also achieves the goal of enhanced wildlife habitat. rH#s s Ma iW /3 If t-1 ST-ft W. r# 1 GvA�s T,�g-fir. Recreation. Education. and Research Planned trails, s, wildlife observation points and cleaner water thin a diverse system of wetland types could provide numerous opportunities for public enjoyment of Renton environments. The wetland environment in Renton will become a favorite place to recreate and learn, particularly if utilized by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington, Lake Washington Community College, South Seattle Community College, Renton wetlands could be the subject of further study by interested wetland research scientists over the coming decades. ' drftmtig.pin 5 City of Renton - DRAFT 55-1779-07 October 6, 1993 S CHAPTER 2. POLICY ISSUES Three policy issues were identified by the City and project team that require discussion and resolution and are identified and discussed below. Should the Mitigation Sites be Used-ftr i -s ri•r� use a P ?!„f v� v �,•�l .`5 eye °�G� �, �L l� �� e�'� Ie° �� Anarc to the city is developing criteria for use of the mitigation bank that will allow expanded opportunities to compensate for city-sponsored j ts. As currently s�V,,p conceived, the mitigation bank would limit eligible-projects to-those wi ar al impacts less than �~st� ' one acre in isolated wetlands and wetlands above the headwaters (thereby eliminating the Corps of Engineers Section 404 permit process and the Washington Department of Ecolo -�7la�s ' .gy_'s Pre- z OUT Disc�e Notification Nationwide Process), and to projects that do not require a Shoreline Substantial Development Permit(thereby eliminating Washington Department of Ecology review cMaAv�ti 5� 5'°'through the State Shoreline Management Act). We understand that there may be some cases where the city needs or desires to utilize the mitigation bank for projects requiring one of these permit reviews. Under the current ordinance, a wide range of city-sponsored activities can occur in wetlands without obtaining a special permit. These activities include: • Activities affecting a single, hydrologically isolated Category 1 and 2 wetland less than 2,200 sq ft within a property boundary are exempt (4-32-4.C.1). • Activities affecting hydrologically isolated Category 3 wetlands less than 5000 sq ft within a property boundary are exempt (4-32-4.C.2). F(4L P,e. Pr, 1. PMv)of A'"oEo z- �,1 4 PR°�F�r Fw>M P�v�Tf yes r d So��z TAXP h�Q ftmtig.pin pUA-AnS 6 City of Renton - DRAFT 55-1779-07 October 6, 1993 y. f-9-5 .r/61,r JUL owe i cCS • Normal and routine maintenance and repair of existing facilities where no alteration of the wetland or additional fill materials will be placed (4-32-4.A.4). The area must be restored to original conditions. • Normal and routine maintenance and repair with minimum placement of fill to bring ' facility up to established safety standards (4-32-4.A.5). Impact must be minimized and area restored. • New surface water discharges to Category 1, 2 and 3 wetlands where discharge meets ' Storm and Surface Water Drainage Ordinance (Chapter 22) and will not result in 4 - c,�t ar, � /e.Y�_o, significant changes in water temperature or chemical characteristics, arm any changes in 1 hydrology that would result in greater wetland function and value (4-32-4.A.9). • Regional stormwater management facilities designed consistent with Ecology's Wetlands ' and Stormwater Management Guidelines (4-32-4.A.12). • Enlargement of facilities beyond existing needs provided footprint does not increase more than 10% within the wetland or its buffer (4-32-4.C.6). • Emergency activities 4-32-4.D . g Y ( ) As outlined above, the Wetlands Management Ordinance (No. 4346) allows outright a wide range ' of city-sponsored activities whose impacts could be compensated for through the use of the mitigation bank. However, the ordinance does not make special provisions to allow for impacts ' above and beyond those identified above solely because a project is city-sponsored. As the mitigation bank is developed and codified, the City could amend Ordinance No. 4346, Section 4-32-6.G-Cooperative Wetlands Basin Planning, Mitigation Banks, or Special Area Management Plans to specify additional parameters for city use of the bank to encompass situations that do enot conform with the basic "small project" concept of the bank. ' drftmtig.pin 7 City of Renton - DRAFT 55-1779-07 October 6, 1993 1 Should the Mitigation Sites be Used for Impacts to Category 2 Wetlands, or Only for ' Projects Impacting Category 3 Wetlands? iIn early conversations about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting Category 3 wetlands should be eligible to use the bank. The general reasoning for this idea was that these wetlands would tend to be the smallest and lowest value wetlands, and that any permitting decisions would largely be a City responsibility. The ' primary exception to this concept would occur for Category 3 wetlands between one and ten acres in size, where impacts over an acre would require Section 404 or Ecology review. However, our review of the Wetlands Management ;:::;;;:.;.,:::.::::::::::;:;::;..:;.:::>::: ::::;:::;,:<.>:::;:;.:.:;.>;,:;<:>. g ent Ordinance '# ti + IAtd;iez ..: ndicates ..:..........................................................................::::: .>: that some Category 2 wetlands could meet the "small project" concept of the bank (e.g., no ' Section 404 or Shoreline review) and therefore be eligible to use the bank unless specifically ' precluded from the program. In fact, because the ordinance does not specifically state that Category 1 wetlands cannot be altered, it is conceivable that impacts to a Category 1 wetland could also meet the "small project" concept. In addition, it is conceivable that city-sponsored projects may impact Category 2 wetlands. One of the goals for the mitigation bank is to provide ecologically sound opportunities for achieving wetland compensation objectives when on-site options are not feasible. As criteria for eligibility requirements are developed, specific requirements for each category of wetland should be considered. Criteria should, in part, be ecologically based so that off-site compensation for impacts to Category 1 wetlands, for example, would be allowed because of the "value added" ' effect of habitat creation as part of a larger planned system. This will be a difficult distinction to articulate, but in an ecological context it is an important distinction that will help screen the ' most appropriate and important sites for bank eligibility. drftmtig.pin 8 City of Renton - DRAFT 55-1779-07 October 6, 1993 Should the City be Solely Responsible for Managing the Mitigation Program and Mitigation Sites? When the Renton mitigation bank was conceived,federal wetland mitigation policy acknowledged mitigation banking as a viable strategy. Recent guidance from the Corps and EPA, dated August ' 23, 1993, outlines requirements for establishment and use of wetland mitigation banks in the Clean Water Act Section 404 regulatory program. Two key elements of the guidance pertaining ' to mitigation sequencing and implementation agreements are particularly challenging for local mitigation banking programs. These two elements essentially require that: (1) local mitigation ' decisions adhere to the federal requirements for sequencing (i.e., avoidance, minimization, compensation) following analysis of practicable alternatives; and (2) that all relevant resource agencies agree in writing as to the purpose, implementation, use and maintenance of the ' mitigation bank. City staff recognize that these program elements are desirable for maximizing resource protection and minimizing overlapping and/or contradictory regulatory requirements; ' however, gaining an agreement between all relevant resource agencies in a short time frame would be difficult. With the City's near-term requirement to provide compensation for the Glacier Park properties, it was agreed that the bank should be established for projects that only require a City permit decision, and that the bank should be managed by the City. This current ' effort will allow the City to develop a mitigation banking "demonstration" project that is relatively simple to implement because it will not require the commitment of time necessary to gain concurrence among several resource agencies. During the course of this project, the future potential for a more broad-based mitigation bank that is also usable for projects requiring Section ' 404 and Shoreline Substantial Development permits will be evaluated. J 0* Tlt� .,nBrr�E', 6f6�►bfl i�t-, I.)r<4L PIWIV�9 �o ,AV J,4C4, T �,)�71,,d/4 ^ 0A J,-CzLrnS G TkAP JAC . C T�i0s� �,e-r . 7R��cE2 Cap �r•y) F6. f- L—r Soo,u ,4rA (,+ �,L k/!�0 G YES C-�.W-o v5E 5<fE E �t5 U4y �spaNSl�slt»y A-No R- 51 ' drftmtigpin ,,,•• // 9 City of Renton - DRAFT 55-1779-07 ��NS� yCLPyM�• October 6, 1993 CHAPTER 3. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANK In general, eligibility criteria for use of the mitigation banking program are based on regulatory requirements and ecological consideration. The eligibility criteria for the City's program would ' determine which wetlands in the Black River drainage basin may be altered and subsequently compensated for at a mitigation banking site. A draft list of eligibility criteria are presented ' below and are shown in Figure Does the Proposed Project Comply with City Ordinance Number 4346? Projects that have unavoidable and necessary impacts would be considered for incorporation in the wetland mitigation banking program provided that they demonstrate compliance with all standards of the City's ordinance. For example, use of the mitigation bank to compensate for ' wetland impacts would be tied to the mitigation policy of sequential mitigation actions including avoiding adverse impacts, taking affirmative measures to minimize impacts, and compensation for impacts. Mitigation banking is basically a form of compensatory mitigation. In addition, the mitigation should be comprised of higher category habitat than the altered habitat, so that similar or greater functions and values in the drainage basis are achieved [see section 4-32-6 (A)(2)], and the City's standards for wetland creation and/or restoration are met. Is the J Proposed Project Located Within the Black River Drainage Basin? P g The altered wetland must be located within the Black River drainage basin, including the Green River lley. drftmtig.pin 10 City 9f Renton - DRAFT 55-1779-07 October 6, 1993 What is the Size and Category of the Wetland That May be Affected? Wetlands classified as Category 1, 2, or 3 wetlands by the City that may be altered consistent ' with Ordinance 4346 are potentially eligible for use of the mitigation banking sites. However,the altered wetland or altered portion of a wetland must be less than one acre, and either isolated or ' above the head waters. Written documentation from the U.S. Army Corps of Engineers on the jurisdictional status (i.e., isolated, above the head waters) of the wetland to be altered would be required. In addition, the altered wetland cannot be considered a shoreline of the state. %H /UO- ' Is On-site Mitigation Feasible? Off-site Versus On-site Mitigation Feasibile? 1 The wetland to be altered would be considered eligible for use of the mitigation banking program g g P gram when: po("-9 On-site mitigation is infeasible (e.g., would deny reasonable use of the property, not �3 A/�e practical due to problems with hydrology, soils, or other factors, surrounding land uses) cr- • On-site mitigation is undesirable from a wetlands resource and ( ve landscape perspective Le P P when on-site mitigation would result in wetlands or aquatic habitats with minimal or potentially unrestorable functional value). On-site mitigation will not best meet identified regional g wetland preservation. goals (e.g., ' replacement of historically diminished wetland types). ,F ' On-site mitigation cannot replace communities and functions of the altered wetland. , The mitigation banking sites can replace the range of functions and values as those provided by the wetland or aquatic habitat that will be impacted. drftmtigpin /1 City of Renton - DRAFT 55-1779-07 October 6, 1993 MITIGATION BANKING No DOES THE PROJECT COMPLY WITH SOULD NOT BE CITY ORDINANCE NUMBER 4346? ' CONSIDERED Yes No IS THE PROPOSED PROJECT LOCATED WITHIN THE BLACK RIVER DRAINAGE BASIN Yes No IS THE IMPACTED WETLAND LESS THAN ONE ACRE,AND ISOLATED ' OR ABOVE THE HEADWATERS? Yes Yes IS ON-SITE MITIGATION FEASIBLE? No ELIGIBLE FOR MITIGATION BANKING PROGRAM ,T�lf 5_140LJL-0 �V/Ilrroo APO Maolf-101 Determining Eligibility for Use of Mitigation Program i CITY OF RENTON MEMORANDUM DATE: October 14, 1993 TO: Scott Woodbury FROM: David Saxen SUBJECT: Wetland Mitigation Bank - Prelim. Draft Products I have glanced at the drafts of tasks 1B and 1C and have the following comments: Goals and Objectives The goals and objectives are generally sound, however I am a little confused by the applicability of some of the objectives. The objective to "Define Eligibility Requirements for the Use of the Mitigation Sites" seems like an objective of the immediate project (implementation phase), not necessarily relevant to the full life of the bank. The next objective "Provide a 1:1 Replacement..." also seems to me to be an implementation objective. On the other hand, these objectives may be important to run by the public in the meetings. I think maybe this is Tracey's intent, as she mentions in her letter. Ultimately,I imagine objectives for the project to be things such as "Enhancing Wildlife Habitat" or"Providing Flood Storage." These issues are,however, included as parts of the objective to "Establish and Expand a Regional Wetland System Located Near or Adjacent to Springbrook Creek..." It is also my understanding that it is wiser to have one primary objective and several secondary objectives as wetland creation/restoration does not lend itself to achieving a high level of success for all of the many functions that wetlands can perform. Subsequently,the prioritization of objectives would be based on the opportunities and constraints of the sites revealed in the site assessment. For instance,maybe since the project area is so urbanized,the site has less potential for wildlife than it does.for improving water quality. I'm not saying this is true, only possible. Anyway,we have discussed this issue of goals and objectives before. As a way to evaluate how well the objectives are being met,performance criteria can be established. For instance, chemical and/or biotic water quality indicators might show the degree to which a water quality objective is being met. Such criteria would be established after the objectives had been established, after the site assessment. This is my understanding of how the success of the project would be judged,but having little experience in such a project,I may be getting myself into a quagmire! Policy Issues I think the policy issues have been clearly stated. They now need to be resolved by the City. I'm not entirely sure how we proceed from here to decide on these issues. Issue 1 The City would definitely want to use the bank for impacts under one acre, and probably would want to be able to use the bank to mitigate impacts over one acre. I'm not sure how this would work, if the private sector could only mitigate impacts under an acre. I suppose the City would have to go through the Individual Permit process as well. Issue 2 The consultant is correct in stating that Category II and even Category I wetlands are not automatically exempt from qualifying for the bank. I don't think this is necessarily a problem since the higher replacement ratios for such wetlands should make it prohibitively expensive to use the bank, although emergent Category II wetlands have the same replacement ratio as Category III wetlands. Determination of what wetlands qualify for the bank should,to some degree,be based on the market. If the consultant's analysis shows that there are plenty of likely Category III impacts,then we might want to say only Category III qualify for the bank. But if it appears that some Category II impacts will be "needed" to completely utilize the bank...or I should say,if the bank has room to accommodate all Category III and more,then the City might want to keep it open to some Category II. As the consultant mentions,the City itself may very well need to mitigate for Category II impacts due to City projects. It seems like a good idea to leave this open,but to keep it somewhat more expensive. Issue 3 It sounds like we have decided (?)to have the bank be managed solely by the City,meaning only impact under one acre would qualify, at least in the short term. Will this approach detrimentally limit the number of potential users? We haven't seen any analysis showing in the watershed how many potential users there are for the bank. But regulatorily, if that's a word,this approach would definitely be much easier. I wonder, however, if this local approach makes us less likely to receive financial support, if ever it were to be available to establish a"true"mitigation bank. We somehow need to leave open the possibility of expanding the scope of the bank to accommodate federally regulated projects in the future. Draft Eligibility Criteria These criteria seem sound to me. Again, we need to be sure that these criteria would result in a sufficient number of users of the bank (but without creating the appearance that the City is abusing its own SEPA mitigation sequencing to ensure its own project succeeds). Analysis of wetlands potentially qualified for the bank in the valley would roughly determine the extent of wetlands that would be eligible under these criteria. Regulatory Requirements The consultant's assessment of these requirements seems accurate. Has the Corps made a determination yet? ' CHAPTER 4. REGULATORY REQUIREMENTS OF THE MITIGATION ' BANKING PROGRAM HistorieaUy, the regulatory requirements associated with mitigation banks have been based on federal requirements associated with Section 404 of the Clean Water Act (Environmental Law Institute 1993). As currently envisioned administration, management, regulatory control, and general oversight of the mitigation banking program would be the sole responsibility of the City of Renton. However, recent guidance from the U.S. Army Corps of Engineers (Corps) and the Environmental Protection Agency,dated August 23, 1993, outlines requirements for establishment and use of wetland mitigation banks under Section 404 of the Clean Water Act. Two elements of the recent guidance pertaining to mitigation banking, sequencing and implementation agreements or memorandums of agreement, are potentially challenging for the City's local ' mitigation banking program. These two elements essentially require that: (1) local mitigation decisions adhere to the federal requirements for sequencing (i.e., avoidance, minimization, ' compensation) following analysis of practicable alternatives; and (2) that all relevant resource agencies agree in writing as to the purpose, implementation, use, and maintenance of the mitigation bank. ' The City recognizes that these program elements are desirable for maximizing resource protection and minimizing overlapping and/or contradictory regulatory requirements; however, gaining an agreement between all relevant resource agencies in a short time-frame would be difficult. With the City's near-term requirement to provide compensation for the Glacier Park properties,�t was agreed that the bank should be established for projects that only require a City permit decision, and that the bank should be managed by the City. This current effort will allow the City to evelop a mitigation banking "demonstration" project that is relatively simple to implement ' because it will not require the commitment of time necessary to gain concurrence among several resource agencies. During the course of this project, the future potential for a more broad-based drftmtig.pin 12 City of Renton - DRAFT ' 55-1779-07 October 7, 1993 ,.� � �- � I "�-� 1.�.1z�1�C.' �'"L lSs cJ `Jc �/'t�� �r� �— 1 � �!J/'�y2� ��-v �L�.� .-tom ��i{�� J /yea�/ � ��� - mitigation bank that is also usable for projects requiring Section 404 and Shoreline Substantial Development permits will be evaluated. f---I/V �� L S G^�`""r �./L-•�"lor 1 In order for the City to undertake efforts to restore the upland portions of the mitigation banking sites to wetlands, the City will need to pursue and acquire permits. The types of federal permits associated with wetlands that may be needed will be dependent on two primary factors: ' 1. Whether the City chooses to excavate any of the existing on-site wetlands (e.g., reed canary grass wetland vegetation adjacent to Springbrook Creek) as part of the effort to ' restore the functions and ecological communities to the site 2. The results of the jurisdictional determination being completed by the Corps of Engineers If the Corps determines that the wetlands within the mitigation banking sites are adjacent, and the City chooses to excavate a portion of the existing wetlands, a Section 404 Individual Permit ' will be required. Alternatively, if the Corps determines that one or both mitigation sites are above the headwaters, and the City chooses to excavate a portion of existing wetland on the ' mitigation site(s), Nationwide Permits 26 and 27 will be required. The following table identifies permits and regulatory review that may be necessary to implement the City's mitigation bank. In addition to the permits identified below, the City will need to ' iate discussions and negotiate an agreement with the Diking District if Springbrook Creek is to be o Mitigation Banking Site 2. f Springbrook Creek i fito this mitigation banking site would result in removal of 7ortion the existing berm. ' ,�G�.✓lam The City will also need to establish a process or mechanism to notify the Corps when a project proponent is going to use the mitigation banking program to offset losses to wetland resources. rA suggested mechanism is: '� 5 ►`� f "" ' oT 7�-- C raw L .� G Q,e+t c sawn!( �ya c�e.�cQ�,✓�a-� CY drAig�pin 13 City of Renton - DRAFT 5 -1779-07 October 7, 1993 ' 1. The City and the Corps need to agree that there is one individual in each office that will 1 be the point contact regarding Nationwide Permits issued by Corps. ' 2. The City should require a project proponent to submit a copy of the Corps' approved Nationwide Permit before the City allows the project proponent to use the mitigation ' banking program. ' 3. The City should then prepare a form letter that references the Nationwide Permit number and indicates that the City intends to allow the project proponent to use the mitigation banking site(s) to offset losses to wetland resources that were approved under the Nationwide Permit process. The form letter should be sent to the Corps for their files. The types of permits (i.e., federal, state, and local) that may be necessary for the City of Renton ' to restore the upland sections of the mitigation banking sites to wetlands are identified in the table below. This table and any accompanying text will be modified based on the results of the Corps' jurisdictional determination on adjacency, and on the extent and type of work that will be completed on the mitigation banking sites. drftmtig.pin 14 City of Renton - DRAFT ' 55-1779-07 October 7, 1993 Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" Federal § 404 Permit Required for dredge and Corps; Seattle District Clean Water Act, 1)Nationwide permit 26, Section 404 permits AND fill activities in waters of Office §404;33 USC § <1 acre:4-6 weeks;2) Nationwide permits are the U.S. including 1344;33 CFR Nationwide 26, >1 acre: 8 typically valid for a 3-year wetlands. 320 et seq.;40 weeks minimum;3) period, but may be ' CFR Pt 230. Nationwide 27: 6-8 weeks ; extended-through negotiated 4)Individual permit:22 permit conditions. week minimum. NEPA process must be completed ' before permit can be issued. All federal permits or Corps will be the lead 42 USC§4321 et Issuance of final EIS or EA NEPA review(EA or EIS) ' National approvals issued for agency responsible for seq., 40 CFR Pt must precede issuance of must be revisited only if Environmental construction or operation NEPA compliance and 1500 et seq.; 10 any federal permits; there are 1) "substantial Policy Act of the facility trigger compliance will be CFR 1021 (NEPA usually, 30 days must changes in the proposed (NEPA) NEPA procedures;NEPA done through the regulations) elapse after issuance before action" or II) "significant processes must be Section 404 process. federal agency can issue the new circumstances or complete before any underlying permit. information"relevant to federal permits can be environmental concerns. issued. Threatened or Not a separate process; Department of the Endangered An endangered species Varies Endangered instead, requirements will Interior through U.S. Species Act, 16 survey would take varying Species be incorporated(if Fish and Wildlife USC § 1531 et amounts of time depending Assessments applicable) into the Service w/assistance seq.; 50 CFR Pt on site conditions. A Section 404 permit from local jurisdiction 402 Biological Assessment takes process or Nationwide and State of up to 180 days, or more. permit process. Washington Dept. of ESA § 7(c). A Biological Wildlife. Department Opinion, if needed,takes of Commerce through 45 days. 50 DFR§40214 the National Marine (e). Fisheries Service. Historic Compliance must be Corps will be primarily Natural Historic Timing depends greatly on N/A;this review would be a Preservation assured through the responsible for Preservation Act, the resources affected, if component of other permit Review Section 404 or Nationwide compliance. It must § 106, 16 USC § any, and the presence of process. Permit process. take into account 470 et seq.; 36 opposition and likelihood of comments of the US CFR. §§ 60-63, appeal. Advisory Council on 800; 16 USC § Historic Preservation if 469 et seq. Not critical path. ' a protected property or site is identified. State of Washington ' State All state and local permits Probable SEPA lead Specific to each SEPA review must precede As with NEPA, Environmental or approvals issued for agency: City of Renton City/County, the issuance of any state or supplemental environmental Policy Act construction or operation local permits or approvals review is required only if ' (SEPA) of the facility must by 7 days. An EIS and there are I)"substantial comply with the associated studies generally changes to a proposal so procedural requirements take at 10 months to a year that the proposal is likely to of SEPA. A DNS, to complete, assuming no have significant adverse MNDS, notice of appeals. If NEPA review environmental impacts"or adoption, or final EIS is "adopted,"the process II) "new information must be issued before can be completed in about indicating a proposal's agencies issue permits or 1 month after the probable significant adverse approvals. completion of the NEPA environmental impacts. process. 15 October 7, 1993 fiv 1 1 1 1 1 Statutes/ ' Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" Hydraulic An HPA may be required Washington Ch. 75.20 RCW; HPA application must be Permits must demonstrate Project if project cross/affects Department of Fisheries Ch. 220-110 processed within 45 "substantial progress on Approval fresh water streams. WAC calendar days of the construction on that portion (HPA) submission of a complete of the project relating to application and after hydraulic approval within issuance of a final EIS. No two years of the date of public hearing required. issuance." HPA approvals ' may be granted for a period of up to five years. Temporary Required for construction Washington Dept. of Ch. 90.48 RCW; Generally, temporary water None established by Modification of activities that temporarily Ecology,Northwest WAC 173-201 quality modification must regulation;permit terms and Water Quality violate water quality Regional Office. and 173-222. be sought 30 days prior to conditions generally cover Criteria criteria. May be required any in-water work. duration of work requiring for stream diversion the modification. structures. Reclaimed To obtain a reclaimed State Dept. of Health, Ch. 90.46 RCW; No time line for permit None established by statute. Water Use water permit bafote- in conjunction with interim issuance rmit distributing reclaimed Dept. of Ecology. regulations are to established by statute. water for industrial or be finalized by commercial use. Summer 1993. Water Quality Required of any applicant Washington Dept. of Federal Clean Timing of certification Not Applicable Certification (§ for a federal license or Ecology Headquarters; Water Act, varies. 401) permit to conduct any Central Programs; Section 401;Ch. activity that may result in Environmental Review 173-225 WAC any discharge to surface Section, Olympia. waters. CZMP Required for permits and Washington Dept. of 16 USC §1451 et Certification can generally Not applicable Consistency licenses affecting Ecology, Shorelines seq.; 15 CFR be obtained in 60 days. Certification shoreline areas and is Program,Olympia. parts 923-930 usually considered during the Section 404 or ' Nationwide permit process. Water Right Required for diverting X Washington Dept. of `F C4lkE'I d Currently averaging 2 to 3 In perpetuity ' Permit and cfs of water out of waters Ecology,Northwest years. City may already Certification of the state. Regional Office, have a water right permit to Bellevue Springbrook Creek—. - which case eth City will ' need to obtain a change in use permit. Local Shoreline Required for any City of Renton City Shoreline Permit is usually obtained Shoreline permits are valid Substantial substantial development Master Program in 4-6 months. for 2 years. Extensions are Development within 200 feet of a possible. Permit shoreline area. ' Sensitive Area City regulates wetlands City of Renton Strategies for Process occurs upon N tat.-N-#ttp t Regulation through sensitive areas Wetland submittal of any building or WA ordinance. Designation and land use permit review ' Interim and/or to obtain approval of Development use and/or development of Regulations land. (Ordinance No. 4346). Adc, ' 16 October 7, 1993 Statutes/ ' Permit/Requirement Purpose Agency Regulations Timing TPermit"Shelf Life" Grading Permit Must be issued prior to Building Code r~it £ iti<>ieded Grading permits for Grading must begin within 6 start of construction. Division,City of projects are generally months of permit issuance; Renton fyb lily issued within 8-12 weeks. grading permit is valid for fells>ti#SiF the duration of construction. ' ::.. �:.:........... ...............I.................. Land Clearing A land clearing and/or City of Renton 4-9-1 Permits for land clearing Valid one year from date of and Tree tree cutting plan is and tree cutting are issuance. Cutting Permit reviewed as part of the generally issuedityllptl SEPA review and itedti:hWb permitting process. ' 17 October 7, 1993 1 CHAPTER 4. REGULATORY REQUIREMENTS OF THE MITIGATION BANKING PROGRAM ' Historically, the regulatory requirements associated with mitigation banks have been based on federal requirements associated with Section 404 of the Clean Water Act (Environmental Law Institute 1993). As currently envisioned administration, management, regulatory control, and general oversight of the mitigation banking program would be the sole responsibility of the City of Renton. However, recent guidance from the U.S. Army Corps of Engineers (Corps) and the Environmental Protection Agency,dated August 23, 1993,outlines requirements for establishment ' and use of wetland mitigation banks under Section 404 of the Clean Water Act. Two elements of the recent guidance pertaining to mitigation banking, sequencing and implementation ' agreements or memorandums of agreement, are potentially challenging for the City's local ' mitigation banking program. These two elements essentially require that: (1) local mitigation decisions adhere to the federal requirements for sequencing (i.e., avoidance, minimization, ' compensation) following analysis of practicable alternatives; and (2) that all relevant resource agencies agree in writing as to the purpose, implementation, use, and maintenance of the ' mitigation bank. The City recognizes that these program elements are desirable for maximizing resource protection and minimizing overlapping and/or contradictory regulatory requirements; however, gaining an ' agreement between all relevant resource agencies in a short time-frame would be difficult. With the City's near-term requirement to provide compensation for the Glacier Park properties, it was agreed that the bank should be established for projects that only require a City permit decision, and that the bank should be managed by the City. This current effort will allow the City to develop a mitigation banking "demonstration" project that is relatively simple to implement because it will not require the commitment of time necessary to gain concurrence among several resource agencies. During the course of this project, the future potential for a more broad-based ' City n 12 dr tmti . I Renton - DRAFT 1 S P h' of 55-1779-07 October 7, 1993 mitigation bank that is also usable for projects requiring Section 404 and Shoreline Substantial ' Development permits will be evaluated. In order for the City to undertake efforts to restore the upland portions of the mitigation banking sites to wetlands, the City will need to pursue and acquire permits. The types of federal permits associated with wetlands that may be needed will be dependent on two primary factors: ' 1. Whether the City chooses to excavate any of the existing on-site wetlands (e.g., reed ' canary grass wetland vegetation adjacent to Springbrook Creek) as part of the effort to restore the functions and ecological communities to the site ' 2. The results of the Jurisdictional determination being completed by the Corps of Engineers If the Corps determines that the wetlands within the mitigation banking sites are adjacent, and ' the City chooses to excavate a portion of the existing wetlands, a Section 404 Individual Permit will be required. Alternatively, if the Corps determines that one or both mitigation sites are ' above the headwaters, and the City chooses to excavate a portion of existing wetland on the mitigation site(s), Nationwide Permits 26 and 27 will be required. The following table identifies permits and regulatory review that may be necessary to implement r the City's mitigation bank. In addition to the permits identified below, the City will need to �Unr, (.carry �uMWi. DB�GiSd�l��i initiate discussions and negotiate an agreement with the Ong-District if Springbrook Creek ' I n(vM to be diverted into Mitigation Banking Site 2. Diversion of Springbrook Creek into this mitigation banking site would result in removal of a portion of the existing berm. /'4tu,74 1 The City will also need to establish a process or mechanism to notify the Corps when a project proponent is going to use the mitigation banking program to offset losses to wetland resources. A suggested mechanism is: 453UW--s i)a Z/V`1 ' drftmtig.pin 13 City of Renton - DRAFT 55-1779-07 October 7, 1993 ' 1. The City and the Corps need to agree that there is one individual in each office that will be the point contact regarding Nationwide Permits issued by Corps. 2. The City should require a project proponent to submit a copy of the Corps' approved ' Nationwide Permit before the City allows the project proponent to use the mitigation banking program. 3. The City should then prepare a form letter that references the Nationwide Permit number ' and indicates that the City intends to allow the project proponent to use the mitigation banking site(s) to offset losses to wetland resources that were approved under the ' Nationwide Permit process. The form letter should be sent to the Corps for their files. ' The types of permits (i.e., federal, state, and local) that may be necessary for the City of Renton to restore the upland sections of the mitigation banking sites to wetlands are identified in the table below. This table and any accompanying text will be modified based on the results of the Corps' jurisdictional determination on adjacency, and on the extent and type of work that will be completed on the mitigation banking sites. ' dr imti8P in 14 City of Renton - DRAFT f 55-1779-07 October 7, 1993 Statutes, Permit/Requirement Purpose Agency Regulations T Timing Permit"Shelf Life" ' Federal §404 Permit Required for dredge and Corps;Seattle District Clean Water Act, 1)Nationwide permit 26, Section 404 permits AND fill activities in waters of Office §404;33 USC § <1 acre: 4-6 weeks;2) Nationwide permits are the U.S. including 1344;33 CFR Nationwide 26, >1 acre: 8 typically valid for a 3-year wetlands. 320 et seq.;40 weeks minimum;3) period,but may be CFR Pt 230. Nationwide 27: 6-8 weeks ; extended-through negotiated ' 4)Individual permit: 22 permit conditions. week minimum. NEPA process must be completed before permit can be ' issued. All federal permits or Corps will be the lead 42 USC§4321 et Issuance of final EIS or EA NEPA review(EA or EIS) National approvals issued for agency responsible for seq.,40 CFR Pt must precede issuance of must be revisited only if Environmental construction or operation NEPA compliance and 1500 et seq.; 10 any federal permits; there are I)"substantial ' Policy Act of the facility trigger compliance will be CFR 1021 (NEPA usually,30 days must changes in the proposed (NEPA) NEPA procedtrres;NEPA done through the regulations) elapse after issuance before action"or 11)"significant processes must be Section 404 process. federal agency can issue the new circumstances or complete before any underlying permit. information"relevant to ' federal permits can be environmental concerns. issued. ' Threatened or Not a separate process; Department of the Endangered An endangered species Varies Endangered instead, requirements will Interior through U.S. Species Act, 16 survey would take varying Species be incorporated(if Fish and Wildlife USC § 1531 et amounts of time depending Assessments applicable)into the Service w/assistance seq.; 50 CFR Pt on site conditions. A Section 404 permit from local jurisdiction 402 Biological Assessment takes process or Nationwide and State of up to 180 days, or more. permit process. Washington Dept.of ESA § 7(c). A Biological Wildlife. Department Opinion, if needed,takes of Commerce through 45 days. 50 DFR§40214 the National Marine (e). Fisheries Service. Historic Compliance must be Corps will be primarily Natural Historic Timing depends greatly on N/A;this review would be a Preservation assured through the responsible for Preservation Act, the resources affected, if component of other permit Review Section 404 or Nationwide compliance. It must § 106, 16 USC § any, and the presence of process. Permit process. take into account 470 et seq.;36 opposition and likelihood of ' comments of the US CFR. §§ 60-63, appeal. Advisory Council on 800; 16 USC § Historic Preservation if 469 et seq. Not critical path. a protected property or ' site is identified. State of Washington State All state and local permits Probable SEPA lead Specific to each SEPA review must precede As with NEPA, ' Environmental or approvals issued for agency:City of Renton City/County. the issuance of any state or supplemental environmental Policy Act construction or operation local permits or approvals review is required only if (SEPA) of the facility must by 7 days. An EIS and there are I) "substantial comply with the associated studies generally changes to a proposal so ' procedural requirements take at 10 months to a year that the proposal is likely to of SEPA. A DNS, to complete, assuming no have significant adverse MNDS,notice of appeals. If NEPA review environmental impacts"or adoption,or final EIS is"adopted,"the process II) "new information ' must be issued before can be completed in about indicating a proposal's agencies issue permits or 1 month after the probable significant adverse approvals. completion of the NEPA environmental impacts. process. 15 October 7, 1993 ' Statutes/ Perm'-Requirement Purpose Agency Regulations Timing FPermit"She=Lifee ' H%draulic An HPA may be required Washington Ch. 75.20 RCW; HPA application must be Permits must demonstrate Project if project cross/affects Department of Fisheries Ch.220-110 processed within 45 "substantial progress on Approval fresh water streams. WAC calendar days of the construction on that portion (HPA) submission of a complete of the project relating to application and after hydraulic approval within issuance of a final EIS. No two years of the date of public hearing required. issuance." HPA approvals may be granted for a period ' of up to five years. Temporary Required for construction Washington Dept of Ch. 90.48 RCW; Generally, temporary water None established by ' Modification of activities that temporarily Ecology,Northwest WAC 173-201 quality modification must regulation;permit terms and Water Quality violate water quality Regional Office. and 173-222. be sought 30 days prior to conditions generally cover Criteria criteria. May be required any in-water work. duration of work requiring for stream diversion the modification. structures. Reclaimed To obtain a reclaimed State Dept of Health, Ch. 90.46 RCW; No time line for permit None established by statute. aS Water Use water permit before in conjunction with interim issuance has been ' Permit distributing reclaimed Dept. of Ecology. regulations are to established by statute, water for industrial or be finalized by commercial use. Summer 1993. Rater Quality Required of any applicant Washington Dept of Federal Clean Timing of certification Not Applicable ' Certification(§ for a federal license or Ecology Headquarters; Water Act, varies. yJ1) permit to conduct any Central Programs; Section 401;Ch. activity that may result in Environmental Review 173-225 WAC any discharge to surface Section, Olympia. waters., CZMP Required for permits and Washington Dept of 16 USC §1451 et Certification can generally Not applicable Consistency licenses affecting Ecology, Shorelines seq.; 15 CFR be obtained in 60 days. Certification shoreline areas and is Program, Olympia. parts 923-930 usually considered during the Section 404 or Nationwide permit process. Rater Right Required for diverting X Washington Dept. of TQ€C000$Lii Currently averaging 2 to 3 In perpetuity Permit and cfs of water out of waters Ecology, Northwest years. City may already �A ' Certification of the state. Regional Office, have a water right permit to l� NBellevue Springbrook Creek in IS which case the City will need to obtain a change in r1 ' FCALI (L ,5wh use permit f+ WRS'E!L A4 �+fbu -OQN z `-o^'1f.1 �r Gnu rurf/fw 4Lp(ry /Nfl4srruwL" r /� C�@.•.+. a�/,M1 �unaai Loca" a�4i ,tY +h.t d,,+wbs STontr� voa4fft urr Hazy vo cfe ��r c , f+Ec6,p� f' uF �1" vfi/Lrf . .Ir 9s.S2 wnc 1-3-= 6 Shoreline Required for any City of Renton City§horeline Permit is usually obtained Shoreline permits are valid Substantial substantial development Master Program in 4-6 months. for 2 years. Extensions are Development within 200 feet e`a possible. Permit shoreline area. ' Sensitive Area City regulates wetlands City of Renton Sylation�� Process occurs uponElflk GM Olf. .... .........:;. Regulation through srnsitivrxreas W submittal of any building or ✓ADO i-61L T— o[dinance.w,-,LASS Dd land use permit review Y 6x76,.Sr.r+S Iand/or to obtain approval of D use and/or development of �1tE h5s"9t.--. R land. (Ordinance No. 4346). 16 October 7, 1993 Statutes/Permit/Requirement Purpose -T Agency Regulations Timing Permit"Shelf Life" I Gntdirrg-Permit Must be issued prior to Code .iGrading permits for Grading must begin within 6 .. ....... FILLstart of construction. D&E-1 City of projects are generally months of permit issuance; • (V(D'ac FfArir P"r PW-OT fk)%JI(AL Renton issued within 8-12-weeks. grading perinit is valid for 156(1 .......... ....... the duration of constructiop. Z-JW Land Clearing A land clearing and/or City of Renton 4-919 tcc- Permits for land clearing Valid one year from date of and Tree tree cutting plan is and tree cutting are issuance. Cutting Permit reviewed as part of the generally issued SEPA review and *#*" permitting process. / t"f-f/C- fv,.-sf (34 15-5-uto le)TS V 57(kKT#&,u 11- 06okp. 1-6 'n'pi i S' 01V6-YC�Aj ' P(t�Mlr grip Sr�� 1WA10 0 t4A 0 1 pit, A IIAWS' of I-frvAo-t6 t �Wv^-k JCW--,-5 --------------- PLW— ANS AK (;a oO A14 'L P 0 ' S?'1C ��.-� � � � � rc„cw, �+'h aF y� ��� yE�r�S E"i''b "'- y� 1 fw 'C' �,�l A� Jr,5, PC(- �s106 PI 7 605UP& wTid ArPOW not ' AMO f t,ar+uNp/Nfr v V,0 17 October 7, 1993 UC I-15-yJ h K 1 14:41 FAEAML I K I X FAX NO. 206 889 8808 P, 02/05 Soil test pit 5 was excavated in an upland area and had a similar profile to test pit 4. Fill occurred from the surface to 2 ft 8 inches. The historic A horizon was observed below the fill and extended 12 inches below the fill, Clay was the dominant soil below the historic A horizon, Black sand was observed at 10 ft 4 inches. The sides of the soil pit were glistening and seepage was evident at 8 ft. 5.3.2.3 Hydrology The source of hydrology for the existing wetlands is primarily precipitation. Wetlands on this site lack an obvious inlet or outlet source. Saturation to the surface and inundation to a depth of 1 inch were observed by Jones and Stokes (1993) in the emergent wetland areas. On the day of the site visit in July 1993 inundation and saturation were not observed in the forested portions, however, wetland hydrology was assumed based on depressional topography, soil characteristics, and bare ground. The functional values associated with these wetlands were rated as low by Jones and Stokes (1993) and David Evans and Associates (199 due to the size of the wetlands, lack of structural and community diversity, and an isolated and disturbed nature. The wetlands are extremely limited in providing sediment trapping, food chain support, and groundwater recharge and discharge. The wetlands and depressional topography provide some flood storage and wildlife habitat. The limited young forested and shrub canopy layers provide some cover for small mammals and birds, 5.3.3 Opportunities Using the results of the analysis of existing information and the field investigation the opportunities and constraints associated with establishing wetlands on the mitigation sites was prepared and are presented below. The natural ecosystems in the valley have been severely altered through the years by development. Reestablishing wetlands on the mitigation sites provides an excellent opportunity for the City to gain wetland acreage in a floodplain area where the added physical functions of stormwater attenuation and biofiltration will achieve the highest value. The mitigation program is a great opportunity for the City to demonstrate that wetland mitigation is feasible and to assist in furthering the concept and technical and administrative approaches of mitigation-4a�. The fact that the City, as a local sponsor, is committed to establishing a mitigation-b%rdv-Hig program that is based on public and private partnerships indicates that the City is on the cutting edge of demonstrating the feasibility of miti ation2,.".R, - g The mitigation program is also an excellent opportunity to develop the framework fore°.'�. in the currentl SovfN conceived form of a demonstration project that is relatively small-scal (e an be developed S � ,vithout entire complement of agencies involved in negotiating and implementation process). aNLh drftmtig pin 11 City of Renton - DR4FT SS-1779-07 0:7tober 14, 1993 UU I-15-J� r K i 14;41 rHKHn1 i K l x h AX NU. ?Ub 88Y bbUb P. 03/Ub Much of the existing wetland on the mitigation sites is of low quality (e.g., young, alder with poorly developed understory, no surface expression of hydrology, encroached on by dense blackberry thickets). Mitigation construction could include enhancement of existing wetlands to improve overall character and quality of system. Jh.F_ 5.3-3.1 Opportunities in Mitigation Site 1 neap ofyyJ•i�e�r Mitigation Site 1 israd acent to atge, high value wetlarids's rati (Category 1 wetlands based on the Cit Y rating system) which will not be filled or alte:red in the future. This provides the Opportunity to protect created wetlands on Mitigation Site 1 and the possibility of increased functional values (i.e., providing connections between wei:land systems owned by the City for the Purpose of providing habitat corridors and open space for passive uses) within d between the neighboring wetland systems, jnvews „�i(4e ud r lam/ , Mitigation Site 1 provides an opportunity to increase the acreage capacity of flood storage, This site may provide storage opportunities for localized runoff from adjacent and upstream developments as well as backwater storage from Springbrook Creek. A recent proposal by R u to re-align Springbrook Creek would route normal flows from SW 43rd Street north past and along the west side of Site 1, then flow east toward Springbrook Creek. It would also route high yY o r`wJ flows along the existing Springbrook Creek channel betw�e,en SW 43rd Street and SW 27th Street. e 1PPn Incorporating a design feature that would route the water through Mitigation Site 1 before flowing east to Springbrook Creek would positively impact Site 1 by providing greater hydrologic support for the entire wetland system as well as provide the hydrology necessary to support hydrophytic vegetation reestablished in the upland areas of the mitigation site. Mitigation Site 1 provides an excellent opportunity for greatly enhancing the wildlife habitat, both aquatic and terrestrial, at this site because of its siz,- and greater isolation from urban development. Thf City of Renton recreation Tans A""' P G � show trails in close proximity to Mitigation Site 1. These trails would provide opportunities for both passive recreation and education. Passive recreation would include bird watching, walking, bicycling?, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban storm% ater quality, etc,, and could be offered by interpretive signage and printed materials. 5.3.3.2 Opportunities in Mitigation Site 2 Mitigation Site 2 is adjacent to a historic natural riparian feature that has since been channelized. The mitigation site's proximity to Springbrook Creek offers an opportunity to provide wildlife linkages to other wetlands and open space areas as well as downstream benefits to fish and wildlife, Mitigation Site 2 offers an excellent and direct opportunity to increase flood storage drftmtig.pin 22 Ciry of Renton -DRAFT 55-1779-07 October 14, 1993 vvi to v.i ♦ i� �� .auu«- . n I fill IIU. LUU UUO UUUU I . U`t/ UJ �t V capacity because of its proximity to Springbrook Creek. The recent proposal mentioned above would not appear to significantly affect opportunities to also re-align a portio of Springbrook Creek through Mitigation Site 2. Diversion of high flows into this mitigation ' e would provide increased water quality improvement for downstream receiving waters and etrital input to benefit neighboring and downstream aquatic organisms. An excellent opportunity exists for greatly enhancing the wildlife habitat, both aquatic and terrestrial, at this site because of its proximity to Springbrook Creek, The City of Renton recreation plans P ( ) show trails along Mitigation Site 2. These trails would provide opportunities for both passive recreation aid education. Passive recreation would include bird watching, walking, bicycling, and photography. Education could focus on wildlife, wetlands, salmonid biology, urban stormwater quality, etc. and could be offered by interpretive signage and printed materials. An opportunity exists to keep some meadow areas relatively dry for small mammals as food source for raptors, which use the area. However, this drier habitat could be wet meadow, thereby meeting the goals for wetland creation. While there are still substantial areas of dry field/small mammal habitat in the area, providing this type of habitat along with other types of habitat increases the overall diversity and features inherent in a higher quality wetland system 5.3.4 Constraints S The City of Renton's wetland ordinance does not recognize enhancement as an acceptable form of compensatory mitigation. There are approximately 25 acres of additional area that could be enhanced and used for miti ation',M : '¢'''" g ;_„e" if the ordinance was modified in the future. The available information on existing hydrology may not bf.-adequate to develop site designs with V\ the level of specificity required to prepare a bid package. No groundwater monitoring has been done on either site to establish seasonal fluctuations which would aid in the design of created 3 wetlands. Ideally, the level of ground water should be Measured on both sites for at least 1 year, Ground water wells constructed of PVC pipe could be installed and monitored over the winter and spring, This additional information would allow the site designs to be modified to reflect the changes in groundwater hydrology on both sites. Information on the level of groundwater 3 relative to the levels in Springbrook Creek have been evaluated. j Perhaps the most challenging current constrain is the depth to ground water and the available hydrology to reestablish wetlands on the mitigation sites. There is little available on-site water to support created wetlands. Wetlands on both sites appear to have developed as a result of surface water accumulation in slight depressional areas where, over time, finer sediments have accumulated and reduced soil permeability. Hydrologic support for Mitigation Site 1 appears to be from local precipitation, and possibly from a drainage ditch that extends along the western and northerly property boundaries, Consequently, wetland hydrologic support is limited mostly to precipitation. Hydrologic support for Mitigation Site 2 appears to also be from local precipitation drftmag.pin 23 City of Renton - DRAFT 55-1779-07 October 14, 1993 •� �� • •• • •.. • ••••••••— ••••• • •a•! !I v. L v v v V v V V V V 1 V J/ V J /lot Y'ruv" to and Springbrook Creek, that extends along the easterly and southerl roe bound extreme storm and flooing ding events. Wetlands on both sates appear t have developed a perched water table that is not hydrologically related to groundwater. Consequently, current wetland hydrologic support is limited to local precipitation. There is a potential that the diking district may place restrictions on reconstructing dikes or removing a portion of the dike adjacent to Mitigation Site 2. The possibility of removing or altering a portion of the dike will need to be discussed with the diking district to develop the site plan for Mitigation Site 2. Because of the depth to groundwater observed on the sites in July 1993, and the fact that filling of both sites has placed ground elevations well above the original floodplain elevations, the costs to excavate and remove soils will be high. In addition, these conditions will make it difficult to establish a hydrologic connection between created wetlands on Mitigation Site 2 and Springbrook Creek. Thus, a balanced cut and fill scenario is unlikely given the depth to which excavation must occur if created wetlands are to utilize groundw<ter hydrology. Export of significant amounts of material is likely. Although the costs for excavation will be relatively high, once hydrology is obtained, wetland creation success probability increases with c espondingly lower landscape costs (i.e., plant material costs), yy Urban development is in close proximity to both saes. Springbrook Creek, adjacent to Mitigation Site 2, is an engineer€d ditch and becomes isolated from other wetland and open space areas with development of adjacent property to the north. Site 1 is relatively more isolated from urban development, and is unlikely to have a major thoroughfare along one of its boundaries (once construction of the gravity sewer system is complete). Nevertheless, this site has adjacent commercial development along its southern boundary, and further development in this area is likely to occur, Z The soil seed bank on both sites probably does not contain some of the important plant species (e.g., rushes, sedges, bulrushes, bur-reed. cattail, water parsley, water lily, etc) which might be used in the mitigation ng wetlands. Existing plant communities express what is held in the seed bank (i.e., black cottonwood, red alder, salmonbeny, reed canarygrass, and Himalayan blackberry). Little wetland soils (e.g., peats or muck) are available on the sites for use in construction of new wetlands. An appropriate planting medium and topsoil may need to be imported to the sites. This raises an issue about the balance between costs and benefits of creating wetlands on the upland portions of the mitigation sites. At what economic level does it become infeasible to do this type of development and implementation and how is that balanced with the intrinsic issues Jr� like habitat value? Ultimately, there must be an economic incentive to proceed -- it is governed by markets, which operate even in the environmental arena.Qxr; F� _ -- /}?�1 ;-i.`."?gx:. .:/:�:k. iL:">> p ilff Q y�,•} .y .:s w- ...L ! I.y.6v.if.Q o .:R •S.A: .. �. •1 :R�::.:�:� '�. drft, [.::L:+:a. •.......:\.<.:F.a.v.A.•.:c::�'�.:G.FL.L�:.lf��.Il:..:Aw:h��v.<Z.. � �Vf'.Z'�]�rI�A{� �.o.'�:: ,\'�.�jT�: A: ..�•� . :.eu,,::R:Ayg:+.+.��Ji:.:ad.�5�;??i ':P. ,.�F:L►L �• ���TTT ov..l:FA t A ci:.:e:FA:4r:Q'!':. aa.e.e.•.... ,,����(}}(gg,, 55-17i9-07 24 City of Renton - DR,4FT SS-1779-07 October 14, 1993 jj iy ji �7 ..._._.._..__.._.._...._.__._...__.._...._.........._..._..._.._...__._........._._.__..__..__._ i _._...._..... _.__._..._._._ 13 I QAv)D.__SA ko a �3 x r-n —__.___ ..__ ___..�?> Lu � llt_._�6LI_C __��� 5._�_.__ R..f-£ .__La�a�_ �►^✓?��rs.._ _....._... _.._._.... _ _i3 _..... 1 G 76._._B#C -._._oo9 ` 01 / Pl ✓+ -.__...__. _ _ ..._..._._... ._..._............. _______.____ _.__._ __;e►� _ _-._T_a____ ____.PA13"-%.I 5CLU?_rjG._ fA ass, ___ ._.._.__._._._�----..__._..��S_.S Via[.4-�r_�r_�✓�__.__F..�_.._..�.N_......_.�_l_�v���.__�!Mf _..__�_ _..._ .. ..._..__�_._.._.... IA" :t _ — .__ 120.._._� -,c Moir l aj.Lrzs ._....... 55 oco f '' � G�........... Fay rd/053 4shttut-1AN1'l/.I�fI�,+J �A... Wetlands within city limits. Wetland Code * Size Wetland Code Size Category 1 ** Category 3 ** W-4 65 W-54 1 or less W-5 20 W-31 W-12 41 W-34 W-35 Category 2 ** W-56 1 -2 W-9 W-25 1 or less W-16 W-40 W-36 W-43 W-6 2-3 W-3 5-6 W-75 W-3 8 W-15 W7N 11 - 12 W-41 W8N W-14 3 -4 W 13C W-33 W-10 12- 13 W-85 4-5 W-22 18- 19 W-13a W-45 W-21 W5C 23 W-32 6-7 W-13b 20 Notes: A portion of W-22 is Wetland Mitigation Site 1 A portion of W-32 is Wetland Mitigation Site 2 * From R.W.Beck 1993,Black River Basin Draft Water Quality Management Plan,Volume 3 and Jones,and Stokes 1991,Critical Areas Inventory,City of Renton Wetlands and Stream Corridors ** Category is based on City of Renton wetland ordinance 1 2 3 SURFACE 4 ~ 6 w w LL ..:...:.:....:.....:.:.:. z_ Q -8 10 -12 -14 Sandy Silty Fill Silty Sand with Mottles Fine Sand Seepage Soil Test Pit Characteristics ® Iron Oxide Layer Wood Debris of Mitigation Banking Site 1 1 2 3 4 5 SURFACE -2 — .............. 4 6 w ..... .. ......> _ w w Z a p 8 , , , \ \ _10 f i \ \ \ \ \ f ................ F tiFti f f f f f -12 f ! F i i -14 Sandy Silty Fill Seepage Silty Sand with Mottles ® Concrete Fine Sand Clay \f\+.\'.\`.\ Black Sand Soil Test Pit Characteristics ® Iron Oxide Layer Sandy Silt/Silty Clay Historic A Horizon of Mitigation Banking Site 2 OCT-15-93 FRI 9:46 PARANETRIX FAX N0, 206 889 8808 P, 01/02 Parametrix, Inc. 5808 Lake Washington Blvd. N.E. Kirkland, WA 98033 206-822-8880 FAX TRANSMISSION COVER PAGE FAX # 206-889-88013 Number of Pages (not including this page) r To: "From: Receiving FAX Number: G� Date: 16 1 /' � -- Time: �L=� Comments: OCT-15-93 FRI 9:47 PARAMETRIX FAX NO. 206 889 8808 P, 02/02 Meeting with City of R,mton Monday, October 18, :.993 1:00 p.m. - 3:15 p.m. AGENDA 1. Written/verbal comments from City on goals and objectives, eligibility requirements, and regulatory requirements (15 minutes). 2. Discussion/resolution of policy issues (30 minutes). 3. Discussion of off-site mitigation program versus mitigation banking program (45 minutes). 4. Discussion of adequacy of hydrology information for the two mitigation sites and implications for development of site designs and schedule for implementing mitigation program/construction wetlands (30 ininutes). S. Discussion of first public meeting scheduled for October 20, 7-9 p.m. (30 minutes). Adjourn. Parametrix, Inc. 0 To: Scott Woodbury Date: October 7, 1993 City of Renton Project No: 55-1779-07 200 Mill Avenue S. Renton, WA 98055 From: Washington Oregon Hawaii ❑ 5700 Kitsap Way ❑ 1231 Fryar Avenue ❑ 7820 N.E.Holman ❑ 1164 Bishop Street Suite 202 P.O. Box 460 Suite B-6 Suite 1600 Bremerton,WA 98312-2234 Sumner,WA 98390-1516 Portland,OR 97218-2859 Honolulu, HI 96813-2832 206-377-0014 206-863-5128 503-256-5444 808-524-0594 206-383-1835 206-838-9810 206-694-5020 Fax:808-523-2995 Fax:206-479-5961 Fax:206-863-0946 Fax:503-256-4221 Xl 5808 Lake Washington Blvd. N.E. 25 N.Wenatchee Avenue Kirkland,WA 98033-7350 Suite 207 206-822-8880 Wenatchee,WA 98801-2236 Fax:206-889-8808 509-664-3290 Fax:509-663-8816 We are transmitting the following materials: Four copies of Chapter 4 - Regulatory Requirements for the Draft Wetland Mitigation Banking Program Plan,and electronic version of-Chapters 1 through 4. Comment:, Please call if you have any questions or require additional information. These are: Per your Request For your Information X For your Review and Approval For your Files For your Action Sincerely, cc: cz— Tracey McKenzie Draft � City of Renton Wetland Mitgation Banking Program Q,apber4 �$ Regulatory Requirements i 1 1 1 1 i 1 1 1 1 1 1993 ' CHAPTER 4. REGULATORY REQUIREMENTS OF THE MITIGATION ' BANKING PROGRAM ' Historically, the regulatory requirements associated with mitigation banks have g ry eq g been based on ' federal requirements associated with Section 404 of the Clean Water Act (Environmental Law Institute 1993). As currently envisioned administration, management, regulatory control, and general oversight of the mitigation banking program would be the sole responsibility of the City of Renton. However, recent guidance from the U.S. Army Corps of Engineers (Corps) and the Environmental Protection Agency,dated August 23, 1993,outlines requirements for establishment and use of wetland mitigation banks under Section 404 of the Clean Water Act. Two elements ' of the recent guidance pertaining to mitigation banking, sequencing and implementation agreements or memorandums of agreement, are potentially challenging for the City's local mitigation banking program. These two elements essentially require that: (1) local mitigation decisions adhere to the federal requirements for sequencing (i.e., avoidance, minimization, ' compensation) following analysis of practicable alternatives; and (2) that all relevant resource agencies agree in writing as to the purpose, implementation, use, and maintenance of the ' mitigation bank. ' The City recognizes that these program elements are desirable for maximizing resource protection and minimizing overlapping and/or contradictory regulatory requirements; however, gaining an agreement between all relevant resource agencies in a short time-frame would be difficult. With the City's near-term requirement to provide compensation for the Glacier Park properties, it was ' agreed that the bank should be established for projects that only require a City permit decision, ' and that the bank should be managed by the City. This current effort will allow the City to develop a mitigation banking "demonstration" project that is relatively simple to implement ' because it will not require the commitment of time necessary to gain concurrence among several resource agencies. During the course of this project, the future potential for a more broad-based ' drftmtigpin 12 City of Renton -DRAFT 55-1779-07 October 7, 1993 mitigation bank that is also usable for projects requiring Section 404 and Shoreline Substantial Development permits will be evaluated. 1 In order for the City to undertake efforts to restore the upland portions of the mitigation banking ' sites to wetlands, the City will need to pursue and acquire permits. The types of federal permits associated with wetlands that may be needed will be dependent on two primary factors: 1. Whether the City chooses to excavate any of the existing on-site wetlands (e.g., reed canary grass wetland vegetation adjacent to Springbrook Creek) as part of the effort to restore the functions and ecological communities to the site ' 2. The results of the jurisdictional determination being completed by the Corps of Engineers ' If the Corps determines that the wetlands within the mitigation banking sites are adjacent, and the City chooses to excavate a portion of the existing wetlands, a Section 404 Individual Permit ' will be required. Alternatively, if the Corps determines that one or both mitigation sites are above the headwaters, and the City chooses to excavate a portion of existing wetland on the ' mitigation site(s), Nationwide Permits 26 and 27 will be required. The following table identifies permits and regulatory review that may be necessary to implement the City's mitigation bank. In addition to the permits identified below, the City will need to initiate discussions and negotiate an agreement with the Diking District if Springbrook Creek is to be diverted into Mitigation Banking Site 2. Diversion of Springbrook Creek into this ' mitigation banking site would result in removal of a portion of the existing berm. The City will also need to establish a process or mechanism to notify the Corps when a project proponent is going to use the mitigation banking program to offset losses to wetland resources. ' A suggested mechanism is: drftmtigpin 13 City of Renton -DRAFT 55-1779-07 October 7, 1993 1 1. The City and the Corps need to agree that there is one individual in each office that will be the point contact regarding Nationwide Permits issued by Corps. ' 2. The City should require a project proponent to submit a copy of the Corps' approved Nationwide Permit before the City allows the project proponent to use the mitigation ' banking program. ' 3. The City should then prepare a form letter that references the Nationwide Permit number and indicates that the City intends to allow the project proponent to use the mitigation ' banking site(s) to offset losses to wetland resources that were approved under the Nationwide Permit process. The form letter should be sent to the Corps for their files. The types of permits (i.e., federal, state, and local) that may be necessary for the City of Renton to restore the upland sections of the mitigation banking sites to wetlands are identified in the table below. This table and any accompanying text will be modified based on the results of the Corps' ' jurisdictional determination on adjacency, and on the extent and type of work that will be completed on the mitigation banking sites. 1 drftmag pin 14 City of Renton - DRAFT 55-1779-07 October 7, 1993 ' Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" ]. Federal §404 Permit Required for dredge and Corps; Seattle District Clean Water Act, 1)Nationwide permit 26, Section 404 permits AND till activities in waters of Office §404;33 USC § <1 acre: 4-6 weeks;2) Nationwide permits are the U.S. including 1344;33 CFR Nationwide 26, >1 acre: 8 typically valid for a 3-year wetlands. 320 et seq.;40 weeks minimum;3) period, but may be ' CFR Pt 230. Nationwide 27: 6-8 weeks ; extended-through negotiated 4)Individual permit:22 permit conditions. week minimum. NEPA process must be completed ' before permit can be issued. All federal permits or Corps will be the lead 42 USC §4321 et Issuance of final EIS or EA NEPA review(EA or EIS) National approvals issued for agency responsible for seq., 40 CFR Pt must precede issuance of must be revisited only if Environmental construction or operation NEPA compliance and 1500 et seq.; 10 any federal permits; there are I) "substantial Policy Act of the facility trigger compliance will be CFR 1021 (NEPA usually, 30 days must changes in the proposed (NEPA) NEPA procedures;NEPA done through the regulations) elapse after issuance before action"or II) "significant ' processes must be Section 404 process. federal agency can issue the new circumstances or complete before any underlying permit. information"relevant to federal permits can be environmental concerns. issued. Threatened or Not a separate process; Department of the Endangered An endangered species Varies Endangered instead, requirements will Interior through U.S. Species Act, 16 survey would take varying Species be incorporated(if Fish and Wildlife USC§ 1531 et amounts of time depending Assessments applicable) into the Service w/assistance seq.; 50 CFR Pt on site conditions. A Section 404 permit from local jurisdiction 402 Biological Assessment takes process or Nationwide and State of up to 180 days,or more. permit process. Washington Dept. of ESA § 7(c). A Biological Wildlife. Department Opinion, if needed, takes of Commerce through 45 days. 50 DFR§40214 the National Marine (e). Fisheries Service. ' Historic Compliance must be Corps will be primarily Natural Historic Timing depends greatly on N/A;this review would be a Preservation assured through the responsible for Preservation Act, the resources affected, if component of other permit Review Section 404 or Nationwide compliance. It must § 106, 16 USC § any, and the presence of process. ' Permit process. take into account 470 et seq.; 36 opposition and likelihood of comments of the US CFR. §§60-63, appeal. Advisory Council on 800; 16 USC § Historic Preservation if 469 et seq. Not critical path. ' a protected property or site is identified. State of Washington ' State All state and local permits Probable SEPA lead Specific to each SEPA review must precede As with NEPA, Environmental or approvals issued for agency: City of Renton City/County. the issuance of any state or supplemental environmental Policy Act construction or operation local permits or approvals review is required only if ' (SEPA) of the facility must by 7 days. An EIS and there are I) "substantial comply with the associated studies generally changes to a proposal so procedural requirements take at 10 months to a year that the proposal is likely to of SEPA. A DNS, to complete, assuming no have significant adverse ' MNDS,notice of appeals. If NEPA review environmental impacts"or adoption,or final EIS is "adopted," the process II) "new information must be issued before can be completed in about indicating a proposal's agencies issue permits or I month after the probable significant adverse approvals. completion of the NEPA environmental impacts. ' process. 15 October 7, 1993 Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" tHydraulic An HPA may be required Washington Ch. 75.20 RCW; HPA application must be Permits must demonstrate Project if project cross/affects Department of Fisheries Ch. 220-110 processed within 45 "substantial progress on Approval fresh water streams. WAC calendar days of the construction on that portion ' (HPA) submission of a complete of the project relating to application and after hydraulic approval within issuance of a final EIS. No two years of the date of public hearing required. issuance." HPA approvals ' may be granted for a period of up to five years. Temporary Required for construction Washington Dept. of Ch. 90.48 RCW; Generally,temporary water None established by Modification of activities that temporarily Ecology, Northwest WAC 173-201 quality modification must regulation;permit terms and Water Quality violate water quality Regional Office. and 173-222. be sought 30 days prior to conditions generally cover Criteria criteria. May be required any in-water work. duration of work requiring for stream diversion the modification. structures. Reclaimed To obtain a reclaimed State Dept. of Health, Ch. 90.46 RCW; No time line for permit None established by statute. ' Water Use water permit before in conjunction with interim issuance has been Permit distributing reclaimed Dept. of Ecology. regulations are to established by statute. water for industrial or be finalized by commercial use. Summer 1993. ' Water Quality Required of any applicant Washington Dept. of Federal Clean Timing of certification Not Applicable Certification (§ for a federal license or Ecology Headquarters; Water Act, varies. 401) permit to conduct any Central Programs; Section 401;Ch. activity that may result in Environmental Review 173-225 WAC any discharge to surface Section, Olympia. waters. CZMP Required for permits and Washington Dept. of 16 USC §1451 et Certification can generally Not applicable Consistency licenses affecting Ecology, Shorelines seq.; 15 CFR be obtained in 60 days. Certification shoreline areas and is Program, Olympia. parts 923-930 usually considered during the Section 404 or ' Nationwide permit process. Water Right Required for diverting X Washington Dept.of T4>?CC4T3tti Currently averaging 2 to 3 In perpetuity ' Permit and cfs of water out of waters Ecology, Northwest years. City may already Certification of the state. Regional Office, have a water right permit to Bellevue Springbrook Creek in which case the City will need to obtain a change in use permit. Local ' Shoreline Required for any City of Renton City Shoreline Permit is usually obtained Shoreline permits are valid Substantial substantial development Master Program in 4-6 months. for 2 years. Extensions are Development within 200 feet of a possible. Permit shoreline area. ' Sensitive Area City regulates wetlands City of Renton Strategies for Process occurs uponty>##p Regulation through sensitive areas Wetland submittal of any building or ...................:................ ordinance. Designation and land use permit review Interim and/or to obtain approval of Development use and/or development of Regulations land. (Ordinance No. 4346). ' 16 October 7, 1993 Statutes/ Permit/Requirement Purpose Agency Regulations Timing Permit"Shelf Life" Grading Permit Must be issued prior to Building Code irit�.. jjlttded Grading permits for Grading must begin within 6 :.>:<:::....................... start of construction. Division,City of projects are generally months of permit issuance; Renton tcstfy; .iy issued within 8-12 weeks. grading permit is valid for G`'tty*:il�Ci15�#'�ty the duration of construction. ,..::...::..::::..:..:.,.,:.: ne :U : ..:... � ..,............... ' .................................. Land Clearing A land clearing and/or City of Renton 4-9-1 Permits for land clearing Valid one year from date of and Tree tree cutting plan is and tree cutting are issuance. Cutting Permit reviewed as part of the generally issued !�rikt SEPA review and rteisdd:tets permitting process. ' 17 October 7, 1993 Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd. N.E. Kirkland,WA98033-7350 206-822-8880•Fax:206-889-8808 Mr. Scott Woodbury October 6, 1993 City of Renton 55-1779-07 200 Mill Avenue South Renton, Washington 98055 Dear Scott: Enclosed for the City's review and comments are draft copies of the goals and objectives for the wetland mitigation program,the policy issues for the City's consideration, and the draft eligibility requirements. The draft regulatory requirements and the conditions assessment along with the electronic version of everything are being sent to you under separate cover. I would appreciate it if the City would review these from the perspective of the type of audience that will receive this material. Please note that the draft cover includes the City's logo. I was thinking that a picture could be used along with the logo for the cover of the overall mitigation program document. Does the City have a photograph that they would like to use for the cover? If so, please provide me with one at your convenience. Also, please note that there are only four draft eligibility requirements. In part this is because we are trying to develop a program where project proponents will not get the perception that they are being burdened with another layer of the regulatory process. There are two other criteria we would like to consider, but inclusion of them requires a discussion with the City. The additional criteria we would like to consider relate to whether or not the City plans on doing all of the mitigation construction, the timing of completion of the mitigation, and assurances that there will be enough money to implement the mitigation. These are identified primarily in the form of questions below: Will the City actually do the mitigation construction on both sites? If so, is the City willing to collect a fee from a project proponent and wait until enough money is accumulated before implementing the mitigation construction? If the answer to the second question is yes, then the development project could not occur until the City had enough funds to complete the mitigation construction of an entire site or a portion of a mitigation site (i.e., phased approach). Would the project proponent be able to undertake the development activity prior to the City completing the mitigation action or would the project proponent also have to wait until the mitigation is constructed? Instead does the City want to assess itself now and & Printed on Recycled Paper Mr. Scott Woodbury City of Renton October 6, 1993 Page 2 contribute a proportion of City revenue and collect a late comer fee to guarantee that money will be available to do the mitigation? Will a project proponent be allowed to construct the mitigation in discrete portions of the mitigation sites as long as the mitigation is done in advance of the project impact, the mitigation action is feasible, and it is consistent with the overall mitigation program? If so, how can the City be assured that there are discrete areas of the mitigation sites where the proposed mitigation will be feasible and how can the City be assured that the mitigation will actually be completed (e.g., by not issuing a permit until the mitigation work is compete and requiring a monitoring/maintenance bond)? I look forward to your comments and suggestions. You can send comments to me or wait until our meeting October 18 to go over them. Please call me at 822-8880 if you have any questions or require additional information. Sincerely, Tracey McKenzie TPM/sh enclosures ' Draft � City of Renton Wetland Mitgation Banking Program 4 1 1 1 � 1993 CITY OF RENTON WETLAND MITIGATION BANKING PROGRAM Prepared for 1 CITY OF RENTON 200 Mill Avenue Renton, Washington 98055 Prepared by PARAMETRIX, INC. 5808 Lake Washington Blvd. NE Kirkland, Washington 98033 October 1993 TABLE OF CONTENTS Page iEXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii CHAPTER 1. GOALS AND OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 MITIGATION PROGRAM OBJECTIVES . . . . . . . . . . . . . . . 1 CHAPTER 2. POLICY ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 CHAPTER 3. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 tTO BE COMPLETED APPENDICES TO BE COMPLETED t t t 1 drftmtig.pin i City of Renton - DRAFT 55-1779-07 October 6, 1993 t t LIST OF TABLES TO BE COMPLETED LIST OF FIGURES TO BE COMPLETED LIST OF MAPS TO BE COMPLETED drftmtig.pin ii City of Renton - DRAFT 55-1779-07 October 6, 1993 EXECUTIVE SUMMARY TO BE COMPLETED 1 1 1 1 1 i ' drftmtigpin iii City of Renton - DRAFT 55-1779-07 October 6, 1993 r ICHAPTER 1. GOALS AND OBJECTIVES r 1.1 INTRODUCTION r The City of Renton is developing a wetland mitigation program and plan that will result in no rnet loss of wetlands. This program will primarily encompass land within the city limits, as well as land outside the city limits that may be annexed in the future. r The City's overall goal is to establish large contiguous wetlands on City property along or nearby Springbrook Creek in the Black River drainage basin. The primary goal in establishing these contiguous wetlands is to use these wetlands to offset impacts to lower quality wetlands by private and public development projects that occur within the same drainage basin. In fulfilling this goal it is the City's intent to balance community desires for economic development and raffordable housing with the responsibility to retain the City's remaining wetlands. This will be accomplished by encouraging higher intensity development in areas already supported by infrastructure and encouraging lower intensity development in areas containing wetlands. The city will also encourage restoring disturbed and lower value wetlands and providing maximum protection to higher value wetlands remaining in the City. The City has recently acquired two parcels of land totaling 45 acres for the purposes of establishing a mitigation program (Figure 1.2 MITIGATION PROGRAM OBJECTIVES Other objectives for the City's wetland program have been identified and are resented below: J t3' P g P r r drftmtig.pin 1 City of Renton - DRAFT 55-1779-07 October 6, 1993 r To Achieve No Net Loss of Wetlands The City of Renton supports the concept of no net loss of wetland acreage, values, and functions by protecting high value wetlands, and requiring restoration of disturbed wetlands or creation of new wetlands to offset losses that are unavoidable (City of Renton Ordinance Number 4336, Chapter 22). In meeting the goal of no net loss of wetland resources, the City encourages the creation of wetlands that will be a higher category than the altered wetland. An additional component of the no net loss objective is to allow multiple or cooperative compensation for one Iproject within the same drainage basin in order to best achieve the goal of no net loss. Finally, the City believes that establishing larger contiguous wetlands for the purposes of a mitigation banking program or offsite mitigation program will achieve the objective of no net loss by providing larger, consolidated, and higher quality wetlands rather than small, scattered, and low tquality wetlands. To Define Eligibility Requirements for Use of the Mitigation Sites iEligibility requirements for use of the two parcels will need to be based on the type and size of wetlands that may be subject to impacts from future development, the wetland functions and Ivalues, the required replacement ratios pursuant to the City's ordinance, compliance with sequencing and other provisions of the City's ordinance, off-site replacement feasibility, and location of the impacted wetland within the basin's landscape. Provide a 1:1 Replacement(1 Acre of Wetland Creation/Restoration for 1 Acre of Impacted Wetland) for 5.33 Acres of Impacted Category 3 Wetland (as Defined by the City's Ordinance Number 4346). The City of Renton and Glacier Park Company entered into an agreement in May 1992 whereby ....................... ' Glacier Park transferred two parcels of land ( ) to City ownership in exchange for development of six parcels that would require filling up to 1 acre of lower quality wetlands on drftmtig.pin 2 City of Renton - DRAFT 55-1779-07 October 6, 1993 each parcel. The City has assumed the responsibility of providing the compensatory mitigation for these one acre fills and has an obligation to implement the compensatory mitigation action. i To Establish and Expand a Regional Wetland System Located Near and Adjacent to Springbrook Creek and Other Significant Wetlands The City of Renton currently owns several parcels of property that contain wetlands (Figure:;:;). The intent of the City is to retain the natural features of these parcels for the purposes of open space and natural resource corridors. The wetlands on these parcels are currently providing some of the recognized functions of wetlands including flood storage, wildlife habitat, water quality ' improvement, and groundwater recharge. Restoring and creating additional wetlands within the two parcels considered in this mitigation program will add to the wetland resource base within ithe City, improve stormwater control, flood storage, and hydrologic value; consolidate wetland mitigation within the Green River valley to enhance wildlife habitat; provide additional ' connections with other wetland parcels under City ownership; and provide passive recreation and educational opportunities through coordination with the City's parks and open space program. Retain Natural Features The community can enhance the natural diversity of Renton by protecting a variety of wetlands, restoring a variety of wetland types, managing them as a connected system, and by linking them together. Add to Wetland Resource Base ' The City desires to use the mitigation program and mitigation banking concept as an opportunity to reverse the trend of wetland losses and begin a positive trend toward wetland gains by restoring some of the historic wetland systems in the Black River drainage. drftmtig.pin 3 City of Renton - DRAFT 55-1779-07 October 6, 1993 lWater Oualit�Improvements ' Constructed wetlands and wetland improvements will be used as biological filters to remove sediments, certain nutrients, and other water pollutants from the drainageways in Renton. In some instances, wetlands will be restored by providing more water from Springbrook Creek to the sites. The result will be cleaner surface waters, improved aquatic habitats, and a more pleasant water-oriented experience for those who live,work and visit Renton. While the wetlands to be established on the mitigation sites have multiple values one of their primary uses will be ' for improving the quality of downstream aquatic environments. ' Improved Flood Control ' By establishing a direct connection of mitigation site 2 to Springbrook Creek, protecting existing wetlands, and restoring wetlands on both mitigation sites, additional flood storage capacity can be added in Renton. This will reduce downstream impacts of storm runoff originating in the ' urban area. These flood storage improvements can often provide multiple benefits, such as wildlife habitat and recreation. Consolidate Wetland Miti ag tion The City of Renton's mitigation program proposes to utilize the wetland mitigation bank concept P g p as the primary means for implementing the mitigation program. With this approach, mitigation efforts are planned where the most suitable sites are identified (Mitigation Sites 1 and 2), acquired and restored in advance of wetland impact. The consolidated wetland mitigation approach also provides opportunities for achieving the wetland mitigation program goals and 1 objectives when on-site options are not feasible. The mitigation banking concept benefits both the community and users of the bank as well as the natural resources that use and/or depend on wetland systems. The bank system utilizes the mitigation requirements for individual users where the details of compensation are preplanned, constructed, and maintained by the City. To satisfy drftmtig.pin 4 City of Renton - DRAFT 55-1119-01 October 6, 1993 1 individual impact requirements, users could either buy mitigation credits from the bank, or could be charged a fee to pay into the bank that would be used b y # `" rt to undertake the mitigation action. Enhance Wildlife Habitat and Habitat Corridors By protecting and restoring a variety of wetland types, and by buffering natural areas from the impacts of nearby development, a diversity of habitats will be established; that diversity will benefit wildlife. The "greenway" corridor concept also benefits wildlife. Expanding existing natural systems and restoring habitats in areas that have been damaged by human activities ' insures better survival of wildlife and wildlife viewing opportunities. The concept of habitat corridors also achieves the goal of enhanced wildlife habitat. Recreation, Education, and Research Planned trails, € , wildlife observation points and cleaner water within a diverse system ................... of wetland types could provide numerous opportunities for public enjoyment of Renton environments. The wetland environment in Renton will become a favorite place to recreate and learn, particularly if utilized by elementary, secondary, and higher learning institutions in the community. Located near the University of Washington, Lake Washington Community College, South Seattle Community College, Renton wetlands could be the subject of further study by interested wetland research scientists over the coming decades. drftmtig.pin 5 City of Renton - DRAFT 55-1779-07 October 6, 1993 CHAPTER 2. POLICY ISSUES Three policy issues were identified by the City and project team that require discussion and resolution and are identified and discussed below. Should the Mitigation Sites be Used for City-sponsored Projects? ' An area of particular concern to the city is developing criteria for use of the mitigation bank that will allow expanded opportunities to compensate for city-sponsored projects. As currently conceived, the mitigation bank would limit eligible projects to those with areal impacts less than one acre in isolated wetlands and wetlands above the headwaters (thereby eliminating the Corps of Engineers Section 404 permit process and the Washington Department of Ecology's Pre- Discharge Notification Nationwide Process), and to projects that do not require a Shoreline ' Substantial Development Permit(thereby eliminating Washington Department of Ecology review through the State Shoreline Management Act). We understand that there may be some cases where the city needs or desires to utilize the mitigation bank for projects requiring one of these permit reviews. Under the current ordinance, a wide range of city-sponsored activities can occur in wetlands without obtaining a special permit. These activities include: ' • Activities affecting a single, hydrologically isolated Category 1 and 2 wetland less than 2,200 sq ft within a property boundary are exempt (4-32-4.C.1). ' • Activities affecting hydrologically isolated Category 3 wetlands less than 5000 sq ft within a property boundary are exempt (4-32-4.C.2). drftmtig.pin 6 City of Renton - DRAFT 55-1779-07 October 6, 1993 i • Normal and routine maintenance and repair of existing facilities where no alteration of the wetland or additional fill materials will be placed (4-32-4.A.4). The area must be restored to original conditions. • Normal and routine maintenance and repair with minimum placement of fill to bring facility up to established safety standards (4-32-4.A.5). Impact must be minimized and area restored. • New surface water discharges to Category 1, 2 and 3 wetlands where discharge meets Storm and Surface Water Drainage Ordinance (Chapter 22) and will not result in significant changes in water temperature or chemical characteristics, and any changes in hydrology that would result in greater wetland function and value (4-32-4.A.9). r • Regional stormwater management facilities designed consistent with Ecology's Wetlands and Stormwater Management Guidelines (4-32-4.A.12). r • Enlargement of facilities beyond existing needs provided footprint does not increase more than 10% within the wetland or its buffer (4-32-4.C.6). r • Emergency activities (4-32-4.D). ' As outlined above, the Wetlands Management Ordinance(No. 4346) allows outright a wide range of city-sponsored activities whose impacts could be compensated for through the use of the ' mitigation bank. However, the ordinance does not make special provisions to allow for impacts above and beyond those identified above solely because a project is city-sponsored. As the ' mitigation bank is developed and codified, the City could amend Ordinance No. 4346, Section 4-32-6.G-Cooperative Wetlands Basin Planning, Mitigation Banks, or Special Area Management rPlans to specify additional parameters for city use of the bank to encompass situations that do not conform with the basic "small project" concept of the bank. drftmtig.pin 7 City of Renton - DRAFT 55-1779-07 October 6, 1993 i r Should the Mitigation Sites be Used for Impacts to Category 2 Wetlands, or Only for Projects Impacting Category 3 Wetlands? In early conversations about the structure of the mitigation bank, the general agreement seemed to be that only projects affecting Category 3 wetlands should be eligible to use the bank. The general reasoning for this idea was that these wetlands would tend to be the smallest and lowest ' value wetlands, and that any permitting decisions would largely be a City responsibility. The primary exception to this concept would occur for Category 3 wetlands between one and ten acres in size, where impacts over an acre would require Section 404 or Ecology review. However, our review of the Wetlands ::; �>.:<:O"6":""'*"""""::;:::;;:. . ds Management Ordinance :''' <:;;:indicates that some Category 2 wetlands could meet the "small project" concept of the bank (e.g., no Section 404 or Shoreline review) and therefore be eligible to use the bank unless specifically jprecluded from the program. In fact, because the ordinance does not specifically state that Category 1 wetlands cannot be altered, it is conceivable that impacts to a Category 1 wetland could also meet the "small project" concept. In addition, it is conceivable that city-sponsored projects may impact Category 2 wetlands. One of the goals for the mitigation bank is to provide ecologically sound opportunities for achieving wetland compensation objectives when on-site options are not feasible. As criteria for ' eligibility requirements are developed, specific requirements for each category of wetland should be considered. Criteria should, in part, be ecologically based so that off-site compensation for impacts to Category 1 wetlands, for example, would be allowed because of the "value added" effect of habitat creation as part of a larger planned system. This will be a difficult distinction 1 to articulate, but in an ecological context it is an important distinction that will help screen the most appropriate and important sites for bank eligibility. drftmtig.pin 8 City of Renton - DRAFT 55-1779-07 October 6, 1993 S 1 Should the City be Solely Responsible for Managing the Mitigation Program and Mitigation Sites? i When the Renton mitigation bank was conceived,federal wetland mitigation policy acknowledged mitigation banking as a viable strategy. Recent guidance from the Corps and EPA, dated August 23, 1993, outlines requirements for establishment and use of wetland mitigation banks in the ' Clean Water Act Section 404 regulatory program. Two key elements of the guidance pertaining to mitigation sequencing and implementation agreements are particularly challenging for local ' mitigation banking programs. These two elements essentially require that: (1) local mitigation decisions adhere to the federal requirements for sequencing (i.e., avoidance, minimization, ' compensation) following analysis of practicable alternatives; and (2) that all relevant resource agencies agree in writing as to the purpose, implementation, use and maintenance of the mitigation bank. City staff recognize that these program elements are desirable for maximizing resource protection and minimizing overlapping and/or contradictory regulatory requirements; however, gaining an agreement between all relevant resource agencies in a short time frame would be difficult. With the City's near-term requirement to provide compensation for the Glacier Park properties, it was agreed that the bank should be established for projects that only require a City permit decision, and that the bank should be managed by the City. This current effort will allow the City to develop a mitigation banking "demonstration" project that is ' relatively simple to implement because it will not require the commitment of time necessary to gain concurrence among several resource agencies. During the course of this project, the future potential for a more broad-based mitigation bank that is also usable for projects requiring Section 404 and Shoreline Substantial Development permits will be evaluated. drftmtig.pin 9 City of Renton - DRAFT 55-1779-07 October 6, 1993 CHAPTER 3. DRAFT ELIGIBILITY CRITERIA FOR USE OF MITIGATION BANK In general, eligibility criteria for use of the mitigation banking program are based on regulatory ' requirements and ecological consideration. The eligibility criteria for the City's program would determine which wetlands in the Black River drainage basin may be altered and subsequently compensated for at a mitigation banking site. A draft list of eligibility criteria are presented below and are shown in Figure <. Does the Proposed Project Comply with City Ordinance Number 4346? Projects that have unavoidable and necessary impacts would be considered for incorporation in ' the wetland mitigation banking program provided that they demonstrate compliance with all standards of the City's ordinance. For example, use of the mitigation bank to compensate for wetland impacts would be tied to the mitigation policy of sequential mitigation actions including avoiding adverse impacts, taking affirmative measures to minimize impacts, and compensation for impacts. Mitigation banking is basically a form of compensatory mitigation. In addition, the mitigation should be comprised of higher category habitat than the altered habitat, so that similar or greater functions and values in the drainage basis are achieved [see section 4-32-6 (A)(2)], and ' the City's standards for wetland creation and/or restoration are met. ' Is the Proposed Project Located Within the Black River Drainage Basin? The altered wetland must be located within the Black River drainage basin, including the Green River valley. drftmtigpin 10 City of Renton - DRAFT 55-1779-07 October 6, 1993 What is the Size and Category of the Wetland That May be Affected? ' Wetlands classified as Category 1, 2, or 3 wetlands by the City that may be altered consistent with Ordinance 4346 are potentially eligible for use of the mitigation banking sites. However, the altered wetland or altered portion of a wetland must be less than one acre, and either isolated or above the head waters. Written documentation from the U.S. Army Corps of Engineers on the jurisdictional status (i.e., isolated, above the head waters) of the wetland to be altered would be required. In addition, the altered wetland cannot be considered a shoreline of the state. Is On-site Mitigation Feasible? Off-site Versus On-site Mitigation Feasibile? The wetland to be altered would be considered eligible for use of the mitigation banking program when: ' On-site mitigation is infeasible (e.g., would deny reasonable use of the property, not practical due to problems with hydrology, soils, or other factors, surrounding land uses) • On-site mitigation is undesirable from a wetlands resource and landscape perspective (Le, when on-site mitigation would result in wetlands or aquatic habitats with minimal or potentially unrestorable functional value). ' On-site mitigation will not best meet identified regional wetland preservation goals (e.g., replacement of historically diminished wetland types). ' On-site mitigation cannot replace communities and functions of the altered wetland. The mitigation banking sites can replace the range of functions and values as those provided by the wetland or aquatic habitat that will be impacted. drftmtig.pin 11 City of Renton - DRAFT 55-1779-07 October 6, 1993 ' MITIGATION BANKING No DOES THE PROJECT COMPLY WITH SOULD NOT BE CITY ORDINANCE NUMBER 4346? CONSIDERED Yes No IS THE PROPOSED PROJECT LOCATED 1 WITHIN THE BLACK RIVER DRAINAGE BASIN ' Yes No IS THE IMPACTED WETLAND LESS THAN ONE ACRE,AND ISOLATED OR ABOVE THE HEADWATERS? ' Yes Yes IS ON-SITE MITIGATION FEASIBLE? No ELIGIBLE FOR MITIGATION BANKING PROGRAM Determining Eligibility for Use of Mitigation Program f arametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd.N.E. Kirkland,WA 98033-7350 206-822-8880•Fax:206-889-8808 V Scott Woodbury September 27, 1993 City of Renton 55-1779-07 200 Mill Avenue S. Renton, Washington 98055 Dear Scott: Enclosed is an invoice for services rendered through August 31, 1993. Work performed during this period included: Task 1A - Project Management Coordination with the City and general project management. Task 1B - Regulatory/Resource agency Coordinntion Coordination with the US Army Corps of Engineers regarding an adjacency determination. Preparation of regulatory requirements for the mitigation project. Task 1C - Mitigation Goals and Objectives Preparation of draft technical memorandum of goals, objectives, and policy issues associated with the project. Task 1D - Conditions Assessment and Field Work Computer assistance from CADD operators for mapping, site visit with the project team and City to evaluate the existing conditions and opportunities ad constraints, and analysis of existing information. If you have any questions or require additional information, please call me at (206) 822- 8880. Sincerely, PARAMETRIX, INC. Tracey P. McKenzie �0� Printed on Recycled Paper SEP- 9-93 THU 13:33 PARAMETRIX FAX N0, 206 889 8808 P. 01 Parametrix, Inc. 5808 Lake Washington Blvd. N.E. Kirkland, WA 98033 206-822-8880 FAX TRANSMISSION COVER PAGE FAX # 206-889-8808 To: Scoff Wa.c�buv� Fax#: From: !1C! l C. .Qm? ................................................. U Date: Number of Pages (Total): 3.................................................. Comments: r .............................................................................................................................................................................................................................................. ........................................................................................................................................................................................................................................... SEP- 9-93 THU 13:33 PARAMETRIX FAX N0, 206 889 8808 P. 02 SOIL TEST PIT RESULTS CITY OF RENTON MITIGATION PROGRAM MITIGATION SITES 1 AND 2 Mitigation Site 1 Soil Test Pit 1 Excavated near wetland flag M51. Fill from surface to 22 inches. Silty sand with heavy mottles 2 feet 6 inches below layer of fill. Below silty sand was fine sand. Active slumping evident at 9 feet 3 inches. Soil Test Pit 2 Excavated in northwest corner of site. Similar to Test Pit 1. Fill from surface to about 22 inches, Silty sand with mottles and saturated below 22 inches. Hit silty sand at 7 feet. Soil Test Pit 3 excavated in southeast corner of site. Fill from surface to 22 inches. Below 22 inches was a 3/4 inch long iron oxide layer followed by a silty fine sand layer. Woody debris at 4 feet. Water seepage evident at 11 feet. Mitigation Site 2 Soil Test Pit 1 Test pit excavated on topographic high point in upland area. Hit concrete at 4 feet 5 inches. Soil profile uniform to 9 feet. Sandy silt and silty clay. Clay layer at 9 feet. Blue-gray in color. Clay was saturated. Excavated down to about 10 feet 6 inches. No standing water. Soil Test Pit 2 Test pit excavated in upland area. From 0 to 4 feet 6 inches soil is sandy and mottled. Mottling at 6 inches and soil was wet at 18 inches. Silty clay at 24 inches. Evidence of rooting as deep as 5 feet. At 5 feet was a silty clay that was saturated and mottled. Blue clay at 6 feet 6 inches. Living roots evident in the blue clay layer down to about 7 feet. At 9 feet 7 inches the soil was silty clay and saturated with Evidence of living roots. Lens of organic material with woody debris and black wet sand below 10 feet. Water at 11 feet 4 inches and seepage evident at 9 feet 6 inches. Water depth was determined to be at 9 feet 6 inches. SEP- 9-93 THU 13:34 PARAMETRIX FAX N0, 206 889 8808 P, 03 Soil Test Pit 3 Excavated in stand of young cottonwoods in a wetland delineated by David Evans and ,Associates. Sandy silt with mottling evident at 9 inches. Soils had more sandy texture above 10 inches and more silt below 10 inches. Oxidized iron zone at 2 feet 8 inches. Damp clay layer with bright mottles at 5 feet 5 inches. Soil Test Pit 4 Excavated in upland area. Soil was sand and gravel fill with silt from surface to 3 feet 9 inches. Historic A horizon of silty clay with mottles 10 inches long below fill. Below historic A horizon there was a 4 inch gleyed layer with strong mottles. Below 10 inches was clay to about 11 feet. Water seepage at 8 feet. Black wet sand at 11 feet. Soil Test Pit 5 Excavated in upland. Similar profile as Test Pit 4. Fill from surface to 2 .feet 8 inches. Historic A horizon below fill 12 inches long below fill. Below historic A horizon was clay. Black sand at 10 feet 4 inches. Sides of soil pit were glistening and seepage was evident at 8 feet. Parametrix, Inc. Consultants in Engineering and Environmental Sciences 5808 Lake Washington Blvd. N.E. Kirkland,WA 98033-7350 f5 206-822-8880•Fax:206-889-8808 Za U rG 1993 '• Scott Woodbury CITY OF RF.t�T� August 24, 1993 City of Renton Engineering DE, 55-1779-07 200 Mill Avenue S. Renton, Washington 98055 Dear Scott: Enclosed is an invoice for services rendered through July 31, 1993. Work performed during this period included: Task 1A - Project Management Coordination with the City, one "kick-off' meeting with the City, and one meeting with the project team. Task 1D - Conditions Assessment and Field Work Computer assistance from CADD operators to create base maps and topographic maps. If you have any questions or require additional information, please call me at (206) 822-8880. Sincerely, PARAMETRIX, INC. 411- Tracey P. 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