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Home My WebLink About03370 - Technical Information Report - Wetland Hydrology Recharge Report � �� Schweikl&Associates 1[c M �p � Civil Engineering, Project Management, & � Consulting WETLAND HYDROLOG� RECHARGE REPORT FOR THE PLAT UF CHERIE LANE II PROJECT NO : 05043 FEBRL?ARY 2007 PREPARED FOR: MR. STEVEN BECK AMBERWOOD, LLC 19129 SE 145TH STREET RENTON, WASHINGTON 98059 PREPARED BY: BRANT A. SCHWEIKL, P.E. SCHWEIKL AND ASSOCIATES, PLLC. 705 SOUTH 9TH STREET, SUITE #303 TACOMA, WA 98405 (253) 815-1700 1 05043_Wetland Hydro[ogy Report_070224.dce 3370 WETLAND HYDROLOGY RECHARGE REPORT FOR THE PLAT of CHERIE LANE II (LUA 03-110) S. 34TH PL. & Wells Ave. S. Renton, Washington 98059 February 2007 Prepared for: ,� A' SCg� MR. STEVEN BECK 4Q� O� _ � AMBERWOOD, LLC '� � 19129 SE 145T" STREET RENTON, WASHINGTON 9g059 � Prepared by: �� Brant A. Schweikl, P.E. � � �°�'6� REPORT #05043 `I hereby state that this Wetland Hydrology Recharge Repoi•t for The Plat of Cherie Lane II has been prepared by me or under my supervision and meets the standard of care and expertise ��hich is usual and customary in this community of professional engineers. I understand that the City of Renton does not and will not assume liabilit�� for the sufficiency, suitability or performance of drainage facilities prepared by me." This analysis is based on data and records either supplied to, or obtained b�, Sch��eikl and Associates, pllc. These documents are referenced within the text of the analysis. The analysis has been prepared utilizin� procedures and practices ��ithin the standard accepted practices of the industry. � 7�i�1� 1�Fctland I i�drol��e� Rci?or( il?U�=-1 duc The Plat of Cherie Lane II LUA 03-110. Parcel Numbers 29230�9040 & 2923059188 WETLAND HYDROLOGY RECHARGE REPORT Project Overvie�i ' The nine lot Plat of Cherie Lane II is located west of the intersection of Wells Avenue South and South 34`h Street, in Renton, Washington. The project lies with in the Black River subbasin of the Duwamish- Green River Basin. The project consists of t��-o existing parcels, Lot 8, Parcel # 29230�9040 & Tract A, #2923059188 of the Stiegmen Short Plat, City of Renton SP (LUA-98-026), 1.75 acres & 1.19 acres, respectively. The overall proposed project consists of two existing parcels (Parcel No. 29230�9040) and Tract A{Parcel l�o. 29230�9188). The parcels are 76,401 sf and 47,301 sf in size, respectively. Currently the site is undeveloped and contains three existing wetlands, ri��o of�vhich appear to be of jurisdictional size, Wetlands "A" & "C". Wetland "B" is small and has been deemed a non jurisdictional wetland and is proposed to be filled with this proposal. The two parcels are divided by an existing City of Renton undeveloped and unopened right-of-way for South 34th Street. The South 34�' Street ROW is undeveloped but has sanitary sewer and storm drainage utilities installed along the length of the ROVV. The surrounding land uses include the single-family residential Plat of V4'insper I to the north, the single-family residential developments of the Stiegman SP and Winsper I to the east, the plat of Cherie Lane I to the south and unplatted/undeveloped parcels of land to the west. The project �vill not include the existing portions of the S. 34th Street right-of-way (RO�') that that ��-ill remain undeveloped and unopened. The project proponents presented the City with a point's paper that showed that the most feasible east-west public RO`'�' extension bet��-�een «'ells Ave. S. and Talbot Road S. is the future extension of the S. 34`h Place (Cherie Lane I). Therefore the existing restrictive covenant that ��-as applied to the underlying Stiegman Short Plat (LL"A-98-026, SHPL-H, ECF} ��ill be rescinded �nd the project �l ill not be required to improve the existing S. 34t� Street RO�'. The project proposes to dedicate an additional 7 feet of south portion of Parcel� ?9230�9188 along the S. 34`h Place ROw' to accommodate a 42 foot public ROW and 32 foot street width. The proposed access for all six (6) proposed single-family lots (R-8 Single-Family Residential) via the existing S. 34`h Place public ROW. There is also a small sliver of land that line along the north boundary line of Lot 3 that will be dedicated to the Citv of Renton as ROW. The project proposes to plat the t��o existing parcels into 6 single-family residential lots in the R-8 Residential zone, t��o ��etland tracts, Tracts "A" & "B" to be preserved, and a TY•act "C" the project's storm«-ater detention tract. All lots ��ill directly front off of , � 05043_�Vetland Hydrology Report_070224.doc South 34�' Place (Cherie Lane II) and receive all of their utility services from the S. 34cn Place ROW, except for their sanitary se��er service for Lot 6 that will connect to the existing 8"f� Soos Creek sanitary sewer main located in the existing S. 34`h Street ROW. The project also proposes to utilize wetland buffer averaging to configure the existing wetland buffers to better suite the development of the property and preserve Wetlands "A" and "C" in the proposed VVetland Tract B that will have a Native Growth Protection Easement applied to the tract. The 1�'�'etlands Report by Alder NVJ will address the wetland buffer averaging plan that ��ill add approximatelv 6,712 sf of additional wetland buffer area Tract B ��etland buffers of Vl'etland A and B. The 200� King County Surface Water Design Manual (KCSWDM) is the storm drainage regulatory manual adopted by the City of Renton. In accordance ��ith the 2005 i KCS`'�'DM, Figure 1.1.2.A Flow Chart for Determinin� Tkpe of Drainage Review Rec�uired, was utilized to determine the type of drainage review that the project is subject to. The results of the storm drainage review type was determined to be a Full Drainage Revie��-, because the project proposes greater than 10,000 sf of new impervious surface and greater than 7000 sf of land disturbing activity. The King Count} Soils Survey Maps provided by the United States Department of Agriculture Soil Conservation Service �vere reviewed to determine the soil characteristics with the project sub basin with respect to the soils susceptibility to landslides and erosion � and its capability for groundwater recharge and surface water runoff. Upon revie��-there is no soil survey mapping available for area. W'etland Evaluation Garet Munger of Alderl�W has prepared two separate Wetland E�-aluations for the Cherie Lane 2 project, dated November 7, 2005 (Revised December 2, 2005) and June 7, 2006. (See Appendia A). In addition B-t��-elve Associates has also prepared a previous study dated September 24, 1996 in conjunction ��-ith the Stiegman Short Plat. As stated in the AlderNVV June 7`h 2006 report, the affects of the surrounding development (including Stiegman SP) have affected the surface and subsurface drainage patterns to the �vetlands on the property resulting in the change in onsite wetland configurations from the study and delineation performed B-twelve Associates. The initial Wetland Evaluation provided by A1derNW delineated the existing wetlands onsite and the City of Renton's ��etland consultant request AlderNW re-analyze it's initial wetland delineation ��ith respect to the apparent differences between the 1996 B- twelve Associates and the 2005 A1derVW ��-etland delineation. The City's wetland consultant, The ��atershed Group, visited the site and required AlderNV�' to re-delineate the wetland due in part to the dry nature of the ��-eather in 2005 calendar year and in attempt to moderate the differences found bet��een the ��-etlands evaluations over time. AlderNW's second VJetland Evaluation Report, dated June 7, 2006, and revised the delineation with some field guidance from the Watershed Group. 4 05043_Wetland Hydrolog��Report_070224.doc Proposed VVetland Recharge , The project is intending to supplement the recharge of as much of existing Wetland "A" j as possible with the a�-ailable clean structure roof water and portions of the rear and side yard sheet flow from the proposed single-family Lot 6. The intent is to minimize the ', potential affects of development upon Wetland "A" and it surrounding buffer and supplement the flows to the wetland hydroperiod to maintain and restore it to it's �� previous and historic levels. Prior to development in the immediate proximity to the project there was a much larger ' upstream contributing basin to VVetland "A' that extended to the western edge of Benson ; Drive S. (SR 515). At that time the wetlands received a larger volume of surface and shallo��ground��ater runoff(subsurface drainage pattern) from the upstream contributing basin than they do at the present time. ��%ith the development of the Plat of Vv insper& �'insper II and especially the Stiegman Short Plat in 1998, the upstream contributing drainage basin ��as vastly decreased in size and therefore the amount of surface stormwater and shallow ground water runoff feeding Wetland "A" was correspondingly reduced in kind. The act of developing the upstream , basin area and adding impervious residential single-family structures and impervious asphalL'concrete surfaces increased runoff, a corresponding decrease in the available pervious surface area for potential infiltration of surface flo��s into the shallow ground ��-ater flo�� (subsurface drainage) and the installation of public roads and storm drainage conveyance systems (Vi'ells Ave S.) all have contributed to the resulting decrease in the ' overall flo�v to the wetland over time. We revie��ed the available Technical Information Report (TIR) from the Stiegman Short ' Plat Prepared by Jim Jager, PE. and found that there were no attempts to replace the flo��s to the wetland that removed by the proposed development, no design recharge or calculations were provided as part of the TIR. The report states that the developed flo��-s including the structures ��-ere collected in underground detention pipes within the Wells Ave ROW and detained to reduce the increased peaks of the developed storm event. From the detention facility the discharge flo��s, no�v reduced to the predevelopment ' levels are released to a tight lined public storm drainage system owned by the City of Renton, ��hich conveys the stormwater runoff through �'etland "A" via the unopened S. ' 34th Street public Right-of-Way (ROW). Hydrologic Wetland H,y�drology Recharge Stormwater Calculations , The clean stormwater runoff from the proposed single-famil�- structure on Lot 6 (0.06 � acres) and a portion of the pervious la��n (0.18 acres) from Lot 6 and Lots 5,6 & 7 , Stiegman Short Plat and approximately 0.25 acres of native wetland buffer�rill be � directed to Wetland A for the purpose of recharge of the wetland and its buffer. See the �� -'etland Recharge Basin I��1ap. B-2, for an analysis of the �vetland recharge capacity. �� ti IU�043_1��etland H�drolog��Rcport_070�2a.do: Over the years the upland developments have cutoff the natural surface flows that most likely have in the past been the source of the recharge and creation of the wetlands located within the Cherie Lane II project site. From our review of past design documents for the uphill developments v�-e found that there was no attempt nor requirement far the developments to provide equivalent wetland recharge the flows to the wetland, therefore the marked decrease in the delineated ��etland area that we found during our wetland study compared to the 1998 Stiegman Short Plat ��etland delineation. The contributing storm drainage basin prior to the past residential development and public roadway construction to the east �vas much larger and at one time most likely extended to the Benson Dri��e S. to the east. Our analysis chose to include approYimately 2.50 acres of native second grow�th forest as the existing basin area for our calculations. This choice of 2.50 acres is a conservative estimate of what the actual basin «-as at the time that Benson Drive ��as constructed. We then performed a rough comparison analysis of basin coefficients that determined that the factor of the (runoff coefficient) x (basin area) for the two basins indicate that the wetland recharge flo��s from our DEV Wet A Basin will be less than that of the existing basin, EX Wet A Basin. `�'e then computed the flows for the two basins utilizing a Santa Barbara Unit Hydrograph (SBUH) modeling ��ith the StormShed 2G Hydrology Model by Engenious Systems, Inc. and confirmed that the proposed recharge flows shall be less than the existing conditions that existed prior to the upstream development. The SBUH Hydrology analvsis printout is enclosed in the Cherie Lane II —Vti'etland Recharge Calculations included as an appendix in this report. The calculations sho�v that for the ?4-hour Type 1� VVater Quality storm event (64% of the 2-year event) that the �X and DEV basin essentially equivalent. As the periodicity of the storm events increase the flow rate in the EX basin flows increase faster than that of the DEV basin, wrhich is ��hat is to be expected. (See calculations). Matching of the higher frequency storm event flo�vs to the wetland provides the most frequent and sustaining modeling of the past wetland hydroperiod. By matching the higher frequency VVater Quality event we are replacing the normal pre-existing flows to the ��etland more often throughout the year �vhich assists in maintaining the hydroperiod over the greatest period of time without over saturating or causing major fluctuations in the h_ydroperiod for the less frequent and larger events. The nature of the existing Wetland A is such that is somewhat located on a gradual slope ��-ith small pocketed isolated areas of shallow pooling ��ater when stormwater flows are present. As part of our proposal to recharge `T�'etland A we are proposing to install 18 lineal feet of an in ground dispersion trench that will fill with �vater prior to overflowing to the surface of the buffer and dispersing over the wetland. One of the main advantages for installing the in ground dispersion trench is to attempt to replace the shallo�;- ground��-ater flows that have been reduced over time by the addition of impervious surfaces installed by the upstream residential developments. The shallow ground��-ater flo��s allow for lengthened periods of soils saturation in periods of minimal or no precipitation. The available storage capacit}� ��-ithin the void ratio of the gravel and that 6 0�043_��etland Hydrology Report_070224.doc of the perforated pipe, our facility ��ill allow a portion of the clean stormwater runoff lii from the roof of the structure on Lot 6 to slo��ly infiltrate over time into the shallow i ground water flo��-. This differs from the less expensive at grade perforated pipe laid on the surface that discharges all runoff to a shallo«- sheet flo�v ��-ithout any potential of , shallo«- ground ��-ater recharge. I Summary In summary, the project has designed an efficient low maintenance method of providing the best available means of sustaining the pre-existing wetland hydrology for Wetland A that will best restore and sustain the wetland characteristics to those that existed prior to substantial upstream development and the resulting affects of declining contributing area. 7 05043_�4'etland Hydrolo�y Report_0:%0224.doc ' 1945 S.375th Street ' S hweikl & A Federal Way,WA 98003 - C SSOCI(lteS�pllc Phone:(253)815-1700 Civil Engineerin , Project Manag� Fax: (252}815-1701 �oytsulting CHERIE LANE II WETLAND RECHARGE CALCULATIONS EX Wet A Event Summary Event Peak Q (cfs) Peak T (hrs) �Hyd Vol (acft) Area (ac) Method Raintype'�� other 0.0221 13.50 0.0230 2.5000 SBUH TYPE1 ' 2 year 0.1375 10.67 0.0861 2.5000 ' SBUH TYPE1 ___. .. . __. 5 year 0.2831 10.50 0.1447 2.5000 SBUH : TYPE1 i „� _ . . .. ...... . .. ___. . ..__._, ' 10 year 0.4291 10.17 ; 0.1975 2.5000 SBUH TYPE1 _ _ _ _ _ ___ _ .__ _ __ _ __ 2� vear 0.6434 10.17 0.2694 ' 2.5000 SBUH TYPE1 ' � _ _ _ _._. __ _ .; _ ___ _ _ _ _ _ 100 year' 0.8773 10.17 ', 0.3463 2.5000 SBUH TYPE1 ' Record Id: EX Wet A Design Method SBliH .Rainfall h-pe TYPE1 ' __ _ __ _ _ Hyd Intv ; 10.00 min Peaking Factor 484.00 , _ _ __ _ ___�.�.__.__ __ ' Abstraction Coeff 0.20 ' _ _____. . _ _ Pec-vious Area 2.50 ac DCIA 0.00 ac _ _ : _ Pervious CN ' 76.00 DC CN 0.00 ' _....._._..___�_ ... _..___ Pervious TC ' 47.42 min 'DC TC 0.00 min ' __._._ . __ .... _ Pervious CN Calc ��,...��_�__.�._.__�.____.,. �__. ... __. _. _ _._,..._ .__- - ' Description ' SubArea Sub cn __ _ Wood,�forest land (Undisturbed,'2nd gro��--th) 2.50 ac 76.00 Pervious Composited CN (AMC 2) . 76.00 __ _ _ _ . _ __ _._ _ Pervious TC Calc _ _ __ __ T�-pe Description Length Slope ' Coeff Misc TT __. __ Sheet �''oods or forest ��-ith dense 300.00 ,1�.00% 0.8000 0.00 0.00 underbrush.: 0.80 ft ' in min Shallo�v Forest �vi heavy ground litter & 114.00 9.50%0 0.1000 1.92 meado�vs (n=0.10) ft min 8 050�}3_�Vetland Hydrolog��Report_0,022-�.doc __ _ ___ _ ___ _. __ _ . ._ ._ I, ___, , Pervious TC ', 47.42 ' �� __ � �� min _. _ .__ . _ __ _. _ _. __.___ __._...-- -_.... DEV Wet A Event Summary Event Peak Q (cfs) Peak T (hrs} Hyd Vol (acft) Area (ac) Method Raintype _ other 0.0231 10.17 0.0110 0.4900 SBUH TYPE1 _ __ _ __ _ _ _ _ _ __ _ __ _ ___ 2 year ': 0.0925 10.17 0.0290 0.4900 SBUH TYPE1 '. __ _ _ _ _ _ _ _ _____ _ _ __ _ __ . __: 5 year j 0.1519 10.17 ', 0.0439 0.4900 SBUH TYPE1 ' _ _ _ _ ___ 10 year 0.2033 10.17 ' 0.0567 0.4900 SBUH ; TYPE1 , 2� year : 0.2710 10.17 0.0735 0.4900 SBUH TYPE1 ' 100 year 0.3413 10.17 0.0909 0.4900 SBUH TYPE1 Record Id: DEV Wet A Design Method SBUH Rainfall type TYPE1 ' Hyd Intv 10.00 min Peaking Factor 484.00 Abstraction Coeff 0.20 ,._. ._�.: Pen�ious Area 0.49 ac DCIA 0.00 ac � ______ .___ _. __---__, Pervious CN 83.32 DC CN ; 0.00 ; I �.__... __ _ ____.........______--- ---___._.___._ _�_3 Pervious TC � 25.83 min DC TC ; 0.00 min ; �� _ _... ____ __ _ �___..__._.. __ __ __ _...... _._ _ __ _ ; Per-vious CN Calc ' _._.�_.__.... . _ . _ . _ _ _ _ . . _. _ _ _ Description ; SubArea Sub cn i�-________ _ _ _ _ __ _____ _-________. __ __ _ _ Wood/forest land (Undisturbed/2nd grow�th} 0.25 ac 76.00 ..____ _ _ _ _ __ __ _ _ ____....�__ _ _ _ ; Impe��ious surfaces (pavements, roofs, etc) 0.06 ac 98.00 O en s aces, la��ns, arks ( 7�/o rass) 0.18 ac 86.00 ;; i P P P > -o g _ Pervious Composite CN (A�tC 2) 82.37 � _ ____ _ ____ __ ___ _ .� ,: ___ _ __ _ � __._ _ _ ____ _._ _ _ ' Pervious TC Calc , � _ ___ _ _ _....: , T��pe Description Length Slope ' Coeff Misc TT '' Sheet �'�oods or forest ��-ith dense 100.00 9.44% '0.8000 ?'�� '25.42 min underbrush.: 0.80 ft in ' 'Shallow Short grass, pasture and la�;-ns g0.00 ft 9.44%'0.0300 '0.41 min ' ;(n=0.030) ; _ ____ _ ___ _ __ ___ _ __ _ __ ; � Pervious TC 2�.83 min E i I ' ---�.______________�_ _. _ _ ___��__�________�_ _ _� ..____.________�..._.....___.__.______. _ ..___._ �.. ._.__ _ _ .....�_.�:J 9 OSO43_��'etland Hydroloey Report_070224.doc CITY FILE NO. CHERIE LANE II - PRELIMINARY SHORT PLAT � ' �"� : � � '�Y�'�� - 0 SCALE 1" = 40, �� , ,� S, � ,� q„ fi'�E ' 6 a0' 0 20' 40' 60 ti '��.�� •� ��s� ��'�., � �--' -— A PORTION OF THE SW 1/4 , OF SEC. 29, TWP 23N., RGE. 5E., W.M. �� ' � - { '�� - � � _ •,; --,- _ CITY OF RENTON, KING COUNTY, WASHINGTON S,� ' � _�� ` � "� ' � . - �T .:;� , �3. I-- _ � � _� �� r � �� = �� _ _ _ � s ,� i � �a �' I' -+ — — _ _ L�_-, � S. 32ND STREET - � — � ' — — — ' � � - - ( � / ' --� J- I ' �— t -__'-- -�—_ � � — � _ � � I 30 }9 ____-_—_ . �. ~ �� - \`` _. _ I � � ; � ��1�� I I I I � f I I �-- -'�,� �, S � �� 1� - - �� I I I I I I � I i ��_ _ a,zb s. � I ,� 0 �� + �, � �': � � � ' a �� I 3 � � 5 � 5 ' 1 I 8 � g I 70 I I EJI YET AEMEA BA9NRE1(=2.50g CN f... Y� �" "'�. � . � -� - �-,.\{ r� I � Z � � T o � � � � I , � ' ,`�' �---� - � " � . �� I I PUT 0�MNSPER DINSION II I � � r �- ' ' �� . � I I � ( � 1 ��. VOL. 148 PG'S 5+-56 ' � -. . � . � ! � - II a � �l� . \ � '( �� I I � � I I �' I ris ! �� -� - -- -- — -- �— --- — -�--- _ �� -`��- � �., 5 a I I �� °Ys a u � ��,s•� — - -- � . � � +� � QQQ Q = W N � .-__ , � m � ( r 's` �: 3 I � � ��l � ,\\ + _ _. _� h� e�a;�� ' _ � ,. �-+-r . _ ��. . -r-> ___ - � f'- ��45 ��y+r n�� <� \ b i �� I d -=� 1 I � � � " '\ � �_ 1, ' � _ -- -- � ' �- — — — - �N Nn��e�xo�n��a i - -� ` � STIEGMNI$HORT PLAT ; �,�Ao�. VICINITY MAP �� \ \ I 126 PG 26�2lOA � BASN AREA ASSUNED FOR THE ��a�� c oea yr uer '� �MPoSEU�```��EEETLANO'A'REGiAR�B � � I WRPDSES OF E%HIB171NG ABILIT"0 NTS �a'�� v we t w s v I ' �x� 1�\ II�T k`�REA BA9N�E4=4A9 AC _ ( f � � DI��D LOi 6 FLOWS i0 �►" �' � �� ' PROPERTY OWNER � _x`'+� \� ..,, ' , � T ` `\ \ „ r � TR�nO►�ME�7c)P�i STEVE BECK �o� r' .nx g2913�5 a,,,l,. , g ' , � '� i �'� ��_ _. AMBERWOOD, LLC ,,�� .,. � E NEt OF ._. ._--_ .-- .__- � T\ \ ,.,� � DE�NET rU 7IYE OF NTRATION�TIME(7c)P�7Ft ... -- — ' '��l— i''� 19129 SE 145TH STREET � $m� � ` �� T �\ �, , �� , � I' I � RENTON, WA�iINGTON 98059 �� I ��i �� C I��LAl�E■ ��' ` `,\, " \ 1�`� �-. � �\ 3 � � � `~� , �.., � � � �, � ,�,,.•r i � , SURVEYOR � � � '�, � � � � �� ! � � "m � ' �AVE CAttON, P.E. � /�� "'�` �';� CORE DESIGN,INC. � � � ` � ` N ND aSaER ' N �F "". � ''' _- -_ - t4711 NE 29TH PLACE, SUI1E 101 ,� � : � x t'` � ' � B�°� � � , BELLEVUE. WASHINGTON 98059 w � ,� , � ,�� i � � l is�a,kH a�. i " � �, ,: 3sn�sr. --- -= --�-- ENGINEER � N� "" ', , , � -- , � � � � .,-x-,� "+ i � ' --� ---`� -i--�* +- �-- �- -�-`- --__ - ' $= BRANT A. SCHYYEIKL� P.E. '�' > .�,��seczz � _,...-- ---'i------- - - �_ -- .-- - - - - � � � k�' .i..i..- _ ., � s , -,- �r__ _��_-_ � SCHWEIKL AND ASSOqATES,PLLC -�P--� -- j� L i � •. t ---- -�,°�'-- � -'-- --l--� - --, -- - 4 � ---. —, - --- --- ---� 1945 S. t75TH STREET � �< ---- ? . -�_-, - -- - - � I µ ,� --- - �_ f � ------ ... --�- r � �, �� r FEDERAL WAY,WASHINGTON 98003 �+ a� ��,� � � ' ', �= � � �� ""„uo ' �� i ' `' � PROPOSED BASIN AREA ��a ' �T_�� s � � �� ., ; I�——— _ �� , �I�, t�x/2a2aoseie4 IMPERVI005 AREA = 2621 SF (0.06 AC) � � -/2923C5 , t , � �, ��.,� a � � s �- � I 4 I LAWN AREA = 6014 SF (OJ8 AC) � Y ''� � n �� rc � __ . '�.I DETENTION I NATIVE AREA = 1D,697 SF (0.25 AC) ' ^'�1 � �\ ��\ �� y �' � TRACT ��A» TOTAL AREA � 2t,326 SF (0.49 AC} � i ��" {i � i ` , ', '\. T�;_, �� ,! ?; � EXISTING BASIN AREA � ,, `; � � _ � � � = _ ` � I ..� �,.... ... ' .... . - � � �_ `---' „ _ f � NATIVE AREA = 10B.839 SF (2.50 AC) y . t � _ , = ---,---�,-- -, - W � �__ -� Y �_ ,,,� �-� r�i�- ..-__�_ =rt= � "_��_'^�r �-�--,=;---�--,.1--:�-1+�'--+--�_�,-�-� �" o w 32 I � , 4 COMPARISION OF RUNOFF Z v W �W� � _ � ,_,___. - � � ` : - _ - �_. __ - �_ �--�---�— , . , � ; � � s. o t c9 -� — _ _ . _- _ a • , ' ... EXISTING BASIN = 50 AC x 76 =19 �-- � � � � ------ . } . ( 6) (0 5 76} (0 O6 98) �36 � �' y F� ... ' I - • ' � 65 ___ l� -- Q C PROPOSED BASIN = OJBz9 + .2 x + . x e4 . ��` �� , , vr - — — — � }v�n�aLnc `� I ___---_� ---'--1 � ' . I t TME CALCULATION ASSUMES ITYDROLOqC SOILS GROUP C ANO W�� Q`"� �' � � .da.....�qw� � � ) f � z THE RUNOFF COEFFICIENTS ARE SCS WESTERN WASNINGTON �Z'W �"�'s �i �� I 17 i 1 i °p i �� ( Q I� � RUNOFF CURVE NUMBERS FROM hiE 2005 KING COUNTY �t� '� I � � ' `� �I � � � � » i y 9 � PLAT Oi'WMSPER II � � .� '� SURFACE WATER DESIGN MANUAL, (KCSWDM). �� ?W � �.'� � i � � � +' � VOL. 184 PGS 77-BO T W� ,,__.��-a ;, ., , , � � J I � y --_ -- . — ' -- i � I THE EXISTING BASIN IS AT LEAST AS LARGE AS THE EXI511NG i Z � ' ��.�, � i } J �,� _ � I BASIN BWNDARY SHOWN ABOVE. TNE BASIN AREA IS �� ---- ------- t �� S�, � IDENTIPIED AS THOSE AREAS THAT INITIALLY FEED WETLAND 'A� � �+f�� u - ' � � PRIOR TO 1HE PAST�EVELOPMENT THAT CUT OFF NATURAL W �i'�� ej � � ��l ____ _ �� M 34 � SURFACE WATER RECMARGE TO �NE N£TLAND. � ti � `��, i � ^ m• ! I i ;'' THE PROPOSED BASIN DISCHARGES THE CLEAN ROOF WAiER — � ' � ' I �--�� i i �, � � o � FROM THE STRUC7URE ON LOT 6, A PORTION PERVIOUS LOT 6 I J6 ^� r � � � s 6 � 1 � oo YARD AREA AND THE PERVIWS BACK YARD AREA OF LOT 5, 6 x i � i 15 14 � � 73 1 � ��- - -yT. _ '— — — � `,� & 7 OF TNE S1IEGMAN SP. � - � � � 1 2033 r - - - - THE COMFOSITE RUNOFF VALUE FOR THE EXISTING BASIN IS � �t L �",� � i � � o 1,; � ` ' i i gl - � GREATER THAN THE PROPOSED BASIN COMPOSITE RUNOFF n I �`-- -�� -- ��' ` '\ I I f q j� L r - - �/ � TOOR�ASSIST�P�AR ONDP OR�TO OU RP 0 OS�AND�PASTO I75� Cnackea: BAS -�-- �� + 9 II � ��. _J �_�___ ' � � `` - - ewn: BAS o, UPSTREAM DE�ELOPMENT. soo' `I_S IN Z � `` _ 3 _ _ / Dete. 02/27/Oi ;� CALL 48 HOURS �� , �, ; ,od No oso,3 � ;� � : I 6 BEFORE YOU DIG Snael No.: � � � x '� �, ! � % ��`` �> - - � --_� v' � . , , ., r . � � � ii s„ �� /__ �-,___�- � SITE PLAN 1-800-424-5555 p A sca�: ,•= ao' D'G , o} , s�«,. I Appendices 1. A1derNV�' —Vl�'etland Evaluation November 7. 2005 2. A1derNW —Wetland Evaluation/Buffer Averaging Plan Concept June 7, 2006 3. AlderNV1�'—VVetland A Hydrology Letter, March 1, 2007 I ,� �I I,' 10 i-)�013_11�ctland Il�drolo��Report_G'U_�-1_doc Appendix 1 , AlderN�V — Wetland Evaluation '� November 7, 2005 I�, 11 ' 05043_Wetland Hydrology Report_070224.doc AlderNW November 7, 2005 Revision December 2, 2005 Project No. 20104 Mr. Steve Beck 19129 SE 145th Street Renton,Washington 98056 Subject: Wedand Evaluation Cherie Lane North South 34th Street at Wells Avenue Renton,Washington Parcel#2923059188 and 2923059040 Dear Mr. Beck: As requested, we have conducted a wetland evaluation for the property located near the intersection of Wells Avenue South and South 34th Str�et in the City of Renton. The location of the subject parcel is shown an the attached Vicinity Map(Figure 1). The purpose of our work was to identify the limits of the weiland azeas on and immadiately adjacent to the subject property. We have also reviewed Site Development plans prepazed by . In conducting our site wetland evaluation, we followed the general procedures for the routine on-site methodology as outlined in the Washington State Wetlands Identificatron and Delineation Mamial (March 1997). This procetiure involves analysis of vegetation patterns, soil conditions, and near-surface hydrology in making a determination of wetland coaditions. Our scope of work included site visits in April, 2005 to complete the wetland evaluation and flag the limits of the site wetlands and in October, 2005 to review site conditions for preparation of this report. We had also made a preliminary site visit in May, 2004. The flagged wetland points have bcen surveyed and plotted on project maps as shown on project design plans by Schweikl and Associates,and on the Site Map(Figure 2). WETLAND EVALUATION PROCEDURES For the purpose of this study, we used the wetland definition adopted by the Environmental Pratection Agency(EPA) and the Army Corps of Engineers(COE)for administering Section 404 of the Clean Water Act. According to this definition,wetlands aze: "Those areas that are inundated or saturated by surface water or groundwater at a frequency and duration sufficieat to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes,bogs, and similar areas." (33 CFR 323) 518 North 59�h Street, Seattle, Washington 98103• Phone (206)783-1036 email aldernwC�comcast.net Mr. Steve Beck November 7,2005 Revision December 2, 2005 In Washington State, the Shoretine Management Act and Growth Management Act have amended this definition to exclude some wetland situations by adding the following sentences to the wetland definition: Wetlands do not include those artificial wettaads intentionally created from non-wetland sites, incIuding but not limited to, irrigation and drainage ditches, grass-lined swales, canals, detention facilities, wastewater treat�nent faciliries, farrn ponds, and landscape amenities, or those wetlands created after July 1, 1990, that were intentionally created as a result of the construction of a road, street or Highway. Wetlands may include those artificial wetlands intentionally created from non- wetland areas to mitigate the conversion of wedands. Delineation procedures are based on diagnostic environmental indicators of wetland vegetation, we�tland soils, and wetland hydrology. These procedures, outlined in the Washington State Wetlands Identificatron and Delineation Mam�al (March 1997) are commonly lmown as a Triple Parameter Method. By definition, an area is desig�ated as wedand whe�there are positive indicators for all three parameters. A listing of plant species has been developed for use in the methodology for delineating wetland areas. This listing assigns plant species to one of five indicator status categories ranging from Obligate wetland species, which almost always occur in wetlands,to Upland species, wlrich rarely occw in wetiands. Under normal conditions,hydrophytic vegetation is detemuned to be present if more than 50 percent of the domina.nt species aze in the Obligate (OBL), Facultative Wetland(FACV�, or Facultative(FAC)indicator categories. Diagnostic indicators of hydric soils are related to soil saturation, which leads to anaerobic conditions in the soil. Uader these conditions, decomposition of organic material is inhibited and soil minerals are reduced, creating characteristic soil colors that can be quantified by comparison with Munsell Soil Color Charts. A chroma of one or less in unmottled soils or a chroma of two or less in mottled soils generally indicates a hydric soil. In additioq soils that are saturated during the growing season satisfy a criterion for hydric soils. We used a hand auger and or shovel to collect soil samples from depths of 8 to 18 inches,or below the A horizon. Wetland hydrology is deSned as inundated or saturated soil conditions for at least I4 consecutive days during the growing season. If no water is present at tbe time of evaluation, other indicators may include topographic low points or channels, flood debris, complete absence of vegetation,or presence of hydric soils. GENERAL SITE CONDITIONS The subject property is an approximately 2.7 acre properiy located in the 3400 block of Wells Avenue South in the City of Renton, as shown on Figure 1. South 34th Strcet right-of-way runs through the middle of the property. At present the property is undeveloped. Adjacent properties to the east and north of the project are occupied by existing single family residences of the Winsper development. A new residential development, Cherie Lane is under construction on the property to the south. The site is occupied by a mixed conifer-deciduous forest stand of composed of mostly deciduous trces. Oregon ash (Frazinus latifolia), red alder (Alm�.s rubra) black cottonwood (Populus balsamifera), and big leaf maple (Acer macrophyllum) are the common deciduous trees species on the property. Western red cedaz (Thuja plicata) is the Project No.20104 Page No. 2 �. st�s� rro�em�er�> 2oos Revision De�ember 2, 200s common deciduous tree present on the pmperty. Salmonberry (Rubus spectabilis), snowberry (Symphoricarpos alba),hazelnut(Corylus cornuta),and Himalayan blackberry(Rubus discolor)aze common shrub species present. There are e�cisting sanitary sewer and storm drain pipes following the alignment of the South 34th Street alignment across the property. These pipe lines were installed sometime after 1996. Construction of the pipelines resulted in disturbance to the site in an approximately 30ft wide strip, in an east west orientation through the property. Soils across the property and on much of the surrounding area are mapped as Alderwood gravelly sandy loam (Soil Survey of King Counry, Washington, U.S. Soil Conservation Service, 1973). The Alderwood series is made up of moderately well-drained soils that have a weakly to strongly consolidated substratum at depths of between 24 and 40 inches. The National Technical Committce for Hydric Soils does not list the Alderwood series as a hydric soil although wetland conditions are common in depressional areas within Alderwood soil units. There has bcen coaI mining activity on properties to the south. There may have been some work related to the coal mining activity on the subject property. Surface soils at some locations on the property show evidence of the past activity, and include some coal mine tailings. Our site observations are no� consisteut with tbe Alderwood soil type descriptions. The past ruining activity may explain the differences. Topographically, the property generally slopes down from about elev. 220 along the eastem property line to the low point of about elev. 182 on the southwest praperty comer. . WETLAND AREAS We have identified the limits of three wetland areas on the property as shown on the Site Map(Figure 2). A previous study dated September 24, 1996, by B-twelve Associates, Inc. identified two wetland azeas on tbe property. The configuration of the wetlands identified in their report is similar to that identified during the recent work. Over the nine years since their study was completed tbere has beea considerable new development adjacent to the subject property and the construction of the sanitary sewer and storm drain pipe lines across the property. This work has apparently affected surf�ace and subsurface draiinage patterns on the property, resulting in change in the wetland configuration. Wetland A with an azea of approximately 6,230sq.ft. is located across the east end of the praperty. Wetland B is a small area near the south property line and west of the south end of Wetland A. Wetland C with an azea of approximately 14,OOOsq.ft is the lazgest of the site wetlands. Each of the site wetlands is an isolated area with no defined surface inlet or outlet. Wetiand A Wetland A is an isolated wetland located on the east end of the property. Vegetation within the wetland includes an overstory blactc cottonwood and western red cedar. Understory shrub species include salmonberry, Himalayan blackberry, and red osier dogwood (Cornus stolonifera). Rced canarygrass (Phalaris arundirtucea), soft rush (Juncus e„�`'usus), and creeping buttercup{Ranunculus repens) are herbaceous species within the wetland. Using tbe U. S. Fish and Wildlife Service wetland classi&c�ation system (Cowardin et a1., 1979), the wetland is designated as a palustrine forest wetland habitat. Project No. 20104 Page No. 3 Mr. Stcve Becic November 7,2005 Revision December 2, 2005 Hydrologically this we#land is supported by scepage into the northeast end of the area. At tbe time of observatioa�s in April, 2005, there was surface drainage entering the wetland from the existing development to the east. This surface water moved south through the wetland and dissipated over the south end of the area. It is our urterpretaiion that the wetland would satisfy the criteria for designation as a City of Renton Category 2 wetland. The staudard buffer for a category 2 wetland in the Ciry of Renton is SOft. Wetland B Wetland B is a very small isolated wetland of less than 1,OOOsq.ft, located along the south property line. It is situated within a shallow depression with no defined inlet or outlet. During an initial site visit in April, 2005, soils within the wetland were saturated to near the surface although there was no standing surface water presern. Vegetation within the wetland includes black cottonwood and Oregon ash fornung a canopy over the wetland, with red osier dogwood and Himalayan blackberry as shrub cover. Herbaceous species present include rced canarygrass (Phalaris arundirurcea)and other grasses, soft rush(Juncus e,f�usus), and creeping buttercup(Ranunculus repens). It is our interpretation that the wetland would satisfy the criteria for designation as a City of Renton Category 3 wetland. A.s a srnall isolated wetland of less than 2,200sq.ft. the area can be filled, if mitigation is provided. Mitigation can be provided with storm water treatment and or landscaping. Mitigation for filling Wetland B is being partially provided by the storm water treatment system for the project. � Additional mitigation for the habitat area of the wetland and buffer is being provided in the buffer averaging design ; whereby an additional approximately 2,457sq.ft of upland habitai area is being set aside form development beyond that which would be provided with the uniform SOft buffer. Wetland C Wetland C is the largest of the site wetlands, having an area of approximately 14,OOOsq.ft. It is located on the northwest corner of the property. Vegetation within the wetland includes Oregon ash, black cottonwood and same westem red cedar (Thuja plicata) trces. Understory shrub vegetation includes Himalayan blackberry, snowberry and, salmonberry. Herbaceous vegetation includes, rced canary grass sof� rush. Using the U. S. Fish and Wildlife Service wetland classification system(Cowardin et al., 1979),the wetland is designated as a patustrine forest wetland habitat. Hydrologically, the area is supported by groundwater scepage. The interior topography is somewhat hummocky, creating scattered low areas. At the time of our observations in April, 2005, there was shallow surface water in isolated depressions. There is no defined surface inlet or outlet for the wetland. It is our interpretation that tbe wetland would satisfy the criteria for designation as a City of Renton Caiegory 2 w�tland. The standard buffer for a category 2 wetland in the City of Rernon is SOft. WILDLIFE HABITAT Project No. 20104 Page No. 4 Mr. Steve Beck No�vember 7,2005 RCV1S10A DCCCrt1�T 2, ZOOS We have completed a wildlife and habitat evaluation of the project area, The purpose of our work was to document the existing site conditions to identify hahitats and potential wildlife use of the property. This work was undertaken to determine if there aze criticat habitats on the properiy which would be subject to regulation under Rernon City Code which identifies critical habitats as: ":those habitat areas which mcet any of the following criteria: i.The documented presence of species proposed or listed by the federal govemment or State of Washington as en�dangered,threatened, sensitive,monitor, or prioriiy; and/or ri. The presence of heron rookeries or raptor nesting azeas; and/or iu. Category 1 wetlands (refer to subsection B7b(i)of this Section for classiScation criteria); and/or iv. Portions of streams and their shorelines designated in the Renton Shoreline Master Program, RMC 4-3-090, as Conservancy or Natural(refer to the Renton Shoreline Master Program). c.Mapping: i. Critical habitats are identified by lists, categories and definitions of species promulgated by the Washington State Department of Fish and Wildlife (Non-game Data System Spacial Animal Species) as identified in WAC 232-12-011; in the Priority Habitat and Species Program of the Washington State Department of Fish and Wildlife; or by rules and regulations adopted currently or hereafter by the U.S. Fish and Wildlife Service. ' ri. Referenced inventories and maps are to be used as guides to the general location and extent of criticai habitat. Critical habitat wluch is identified in subsection BSb of this Section, but not shown on the referenced inventories and maps, are presumed to exist in the City and are also protected un�r all the provisions of this section. iii. T'he actual presence or absence of the criteria listad above as deterrnined by qualified professionals, shall govem the treatinent of an individual building site or parcel of land requiring compliance with these regulations.,, During the course of site visits to complete the wetland site evaluation we also made notes regazding observation of wildlife species observed on tbe site. The subject property is occupied by one general vegetation cover type. Lowland mixed forest is the predominant vege�tation cover type across the property. This cover type is based on the habitat caiegories listed in the King County Wildlife Study Guidelines for SEPA (1993). Similaz categories are listed and described in the King County Wildlife Habitat Profrle(1987). The majority of the property is occupied by second or third gowth mixed forest with variation in the relative cover by conifers and deciduous trces. The forest cover on the southern portion of the property is generally dominated by deciduous trees primarily black cottonwood and Oregon ash.. On the northem section of the property trees present include westem red cedar. i Pro'ect No. 20104 J Page No. 5 Mr. Steve Beck November 7, 2005 Revision December 2,2005 WddLfe We have prepared a listing of wildlife species (Table 1) observed or likely to be preseut on the property. This listing is based on species occurrences noted in King County Wildlife Habitat Profrle(1987)and on personal e�erience. A�nphibicros and Reptiles Other than the Pacific chorus frog (Pseudacris regilla), no amphibians were observed during our site visits. These species are generally inactive during fall and winter and aze most frequently encountered during spring and summer. The cover types on this property, particularly tbe forested wetland and adjacent second-growth forest, should provide habitat for several other species of amphibians. The most likely species are the northwestem satamander (Ambystoma gracile) and long-tced salamander (Ambystoma macrodacrylum). The presence of amphibians on the site is limited by the absence of azeas of standing water which might provide breeding habitat for amphibians. The most likely reptiles to be found in the habitais available on this property aze the northem alligator lizard(Elgarra coerulea)and gatter snakes(Thamnophis spp.). Table 1 lists otl�r amplubians and reptiles that could be expected in the habitats present on�is site. The species listed in Table 1 aze based on tables provided by King County (1987) for tl�e habitats described above and on our evaluation of the existing site conditions. Birds Because of their lrigh levels of daytime activity and vocalizations, birds are the most commonly encountered group of vertebrates. Some of the commonly observed species on the site were the black-capped cluckadee (Parus atricappilus), American robin (Turdr�es migratorius), winter wren (Troglodytes troglodytes), and song sparrow 'I (Melospiza melodia). A large number of migratory songbirds including flycatchers, warblers, and vireos are expected on this site during the breeding season. The most likely raptors to use ttus site are the great horned owl (Bubo virginiam�s), Cooper's hawk (Accipiter cooperi), and red-tailed hawk(Buteo jamaicensis). Table 1 lists other bird species expected in the habitats available on this property. Mammals Most mammals tend to be secretive and noctumal, and our observations reflect a relatively sma11 proportion of species that may actually exist on ihe subject property. We observed coyote(Canis latrans)scat on trails azound the property. A large nest, probably built by an eastem gray squirrel (Sciurus carolinensis), was locatsd in the deciduous forest near the north side of the property. Other common mammals that are likely to be present on the site include opossum (Didelphis virginiarra), deer mouse (Peromyscus maniculatus), and raccoon (Procyon lotor). Several species of bats are also likely to be present in these habitats during the summer. Table 1 lists other mammal species expected to occur in the habitats availabie on this site. Threatened. Endan�ered.or Sensitive(TES)S�ecies Critical Habit Two wildlife species included on Washington State listings of TES could be found on or in the vicinity of the subject property. These include the Bald eagle (Haliaeetus leucocephalus), and pileated woodpecker(Dryocopus pileatus). Project No. 20104 Page No. 6 Mr. Steve Becic November 7,Z005 Revision December 2, 2W5 Neither of these species is listed as threatened in the state of Washington. The closegt aquatic habitat which might support either bull trout or Chinook salmon (Oncorhynchus tshawytscha), is in May Creek approximately 2 miles north of the property. Hamey Creek where it is present within the wetland along the east side of the project does not include habitat for either Chinook salmon or bull trout. Bald eagles are found throughout the Puget Sound region. They aze most commonly observed along lake or river shores although they may be found forag�ing over a large area and may roost in larger trees away from bodies of water. No bald eagles were observe on or near the project site. The project site is away from any large bodies of water where they would be likely to build nests. Pileated woodpeckers generally inhabit mature and old-growth forests, or seco�d-growth forests with sufficieut large snags and fallen trees (Rodrick and Milner 1991). Pileated woodpeckers aze also reported to use open woodlands, parks, and wooded suburbs (Ehrlich et al. 1988j and are regularly seen in those habitats in King County: They excavate cavities in snags or large dead branches for nesting and usually make a new nest cavity every year. Nest snags are usually greater than 27 inches in diarneter and taller than 87 feet. There are few large snags withiu the subject property which could be used by pileated woodpecker. During our site visits we did not note the presence of any individuals nor did we no�e any trees with characteristic pil� woodpecker foraging cavities. There is not extensive habitat azea on the property or in the near vicinity which is suitable for pileated woodpecker foraging. Crreai blue herons are not included on the Washington State TES lists although the presence of heron rookeries is identified as a critical habitat in the City of Reaton. No great blue herons were observed on the site during our site � visits and there are no heron rookeries in the near vicinity of the project site. Herons are not likely to use the residential habitats on the property and in the near vicinity Red-tailed hawks are likewise n� included on the Washington State T'ES lists although ra.ptor nests aze identified as critical habitat in the City of Renton. No red-tailed hawks were observed on or in the near vicuuty of the property. Based on our review of existing site conditions it is our conclusion that there are no crirical habitat azeas as defined in tbe City of Renton cvdes, within or in near proximity to the Cherie Lane North project boundary. PROPOSED DEVELOPMENT—WETLAND IMPACTS It is proposed to develop the 2.7 acre property for construction of a 9 lot residential development as shown on project maps by Schweikl and Associates and an the Site Map (Figure 2). Access to the project will be provided from South 34th Place which has bcen partially completad as part of the Cherie Lane project along the south property line. With the exception of the small isolated Wedand B, the site wetlands wiIl be set aside from development within designaied Wetland Tracts. As designed, the project will not result in direct impacts to the preserved site wetlands. The tracts include the wetland areas with a minimum 25ft wide buffer, in accordance with provisions of the Renton City Code which allow buffer averaging. Bufl'er Width Averagine Project No. 20104 Page No. 7 Mr. Steve Heck November 7,2005 Revision December 2,2005 Buffer width averag�ing may be allowed in accordance with RMC where the following steps are taken: i. That the wetland contains variations in ecological sensitivity or there are eacisting physical improvem�ts in or near the wetiand and buffer; and ri. That width averaging will.not adversely impact the wetland function and values; and rii. Thai the total area contained withiri the wetland buffer after averaging is no less than that contained within the required standard buffer prior to averaging; and iv. A site specific evaluation and documentation of buffer adequacy based upon The Science of Wetland Bu„�'ers and Its Implications for the Management of Wetlands, McMillan 24(?0, or similar approaches have bcen conducted. The proposed buffer standard is based on consideration of the best available science as described in WAC 365-195-905; or where there is an absence of valid scientific information, the steps in RMC 4=9- 250F are follow0d. v. In no instance shall the buffer width be reduced by more than fifly percent (50%)of the standard buffer or be less than twenty five fcet (25ft) wide. Greater buffer width reductions require review as a variance per subsection N3 of this Section and RMC 4-9-250B; and vi. Buffer enhancement ia the azeas where tbe buffer is reduced shall be required on a case-by-case basis where appropriate to site conditions,wetland s�sitivity, and proposed land development characteristics. vii. Notification may be required pursuant to subsection F8 of this Section. Wetland bufers are vegetated upland areas adjacent to and generally surrounding wetlands. As such buffers are they provide beneficiai functions within the urbanizing landscape in their reahionship to the the wetland and as upland habitat a.rea. They provide beaeficial functrions as an element of the preserved wetland and as preserved upland habitat. Bu,fJ'er averaging element(i.) Buffer averaging is being applied to Wetlands A and C. Both of these wetlands have been affected by past activities on and adjacent to the property. These include construction of the water and sanitary sewer lines across the property, construction of the existing residential developments to the north and south, and the development under construction to the south. These activities have involved clearing and grading activity within the wetlands and the buffers for the two wetlands. This past activity has affected the majority of the buffer area sunounding the site wetlands. The one section of the buffer which was minimally affected is on the north end of Wetland A which remains forested. T7us area is being preserved and expanded with the buffer averaging. Bu,f�'er averaging elements (ii, iii iv, v and vi) Buffers as an integral unit of the wetland system in urban environment in providing protaction to the wetland habitat, and in providing what have bee,� identified as "sink" and "source" functions. They act to provide protection to the wedand in the form of generating a physical barrier betwcen human activity and the wetland. Project No. 20104 Page No. 8 Mr. Steve Beck No�vember 7,2005 Revision Deoember 2, 2005 "Sink" functions aze those that in effect absorb impacts before reaching the wetland. They serve to moderate water level fluctuations in the wetland; they to mediate chemical and physical impacts to the wetland from erosion, rnovement of sediments and pollutant into the wetland; and to moderate temperatue in the wetland. "Source" functions include the roles served to the wetland system to support wildlife habitat, provide biotic input to the wetland system,and for tbeir role in mediating effects of human disturbance to wetland associated wildlife. These "sink" and "source" functions are related to the vegetative cover on the buffer, the total azea of buffer habitat included, the width of the buffer, surrouading Wpography, and the level of development within the surrounding urban landscape. Exisring residential development activity on and immediately adjacent to the subject property have aff� the effediveness of the wetland buffers. The buffer width has been reduced along the northeast coiner of Wetland A. Construction of the waeter and sanitary sewer lines across the property have affected soil conditions and vegetative cover within a portion of Wetland A and tbe buffer for Wetland C. Additionally the site had been partially cleared in the past, reducing the forest canopy cover allowing the establishmern of non native species incliding Himalayan blackberry and read canarygrass. With buffer avaraging as being proposed for this project there will be no loss in total wetland buffer azea maintained within the project. There will be a ne�t increase in the total buffer area which would be provided with a uniform SOft buffer, of approximaely 2,457sq.ft. With the provision of a somewhat larger habitat area being provided wihtin the two Wetland Tracts, there will be no significant reduction in the "source" buffer function. The preserved buffers can effectively provide roles in maintaining wildlife habitat, and in providing biological support by way of maintaining input of nutrie,nts and organic matter into the sytem. This function within the developed project can be maintained and enhanced with the implementation of buffer enhancement plantings as proposed for the project. As the vegetative cover on the buffer grows and m�atures the effectiveness in pmviding a physical bazrier will be increa.sed. This function can be further enhaaced by the installation of fencing to limit encroachment into the designated wetland tracts. "Sink" functians to protect the wetland will be maintained in part by design of the storm water treatment system. This system can control the movement of stormwater into and through the wetland to minimize impacts on wetland hydrology. This system will likewise limit the movement of unv�run off into the wetlands. The proposed buffer averaging including e�nhancement plantings within the buffer can maintain a level of wetland and buffer function comparable to that wluch would be provided if a uniform SOft buffer were provided within the residential development. New Water Line Construction Project No. 20104 Page No. 9 Mr. Steve Bedc November 7, 2005 Revision December 2,2005 A new water line is proposed to be constructed across the west side of the property. This water line is being constructed to satisfy water service requirements for this property and other residential developments in the azea. Construction of the water line will involve temporary disturbance to approximately 3,034sq.ft. of the buffer for Wetland B. A vegetation restoration planting plan will be prepazed when construction design plans are finalized for the project. This P��S Plan will include details on the number, spacing and species to be placed on the disturbed soils within the waier line easeme�t area. All plant materials to be included in the planting plan will be native to the azea, and to ihe extent possibte species selected will be those native species present on the property. Native trees and shrubs will be included. These plantings are intended to supplement natural regeneration and to accelerate the establishment of native shrub cover on the disturbed area. �� With the implementation of a restoration pLan, the impacts from construction of the water line on the wetland buger can be minimized to the exteat possible and the distwbed areas returned to a stable condition, with native vegetative cover. A final restoration plan will be prepared and submitted for review as final development plaus are prepazed. The restoration plan will be implemen�with the buffer enbancement plantings. Buffer MitiEation/Enhancement PlantinQ Plan We have prepared a conceptuai buffer mitigati�/enhancecnent plan for the project. The general design intent of this plan is to incre�se the density of native trces and shrubs within the preserved buffer and to control the growth of non native invasive species including Himalayan blackberry, and reed canarygrass, among others included on the DOE listing of invasive species. This conceptual plan is prepared to demonstrate the feasibility of construcrion the projed to mcet City of Renton requirements for preserving we�tland and buffer funcrion. A final plan will be prepared as final construction design plans aze completed. The wetland/buffer enhancement plan involves four objectives: 1. Control the growth of invasive plants, including Himalayan blackberry and Scot's broom (Cytisus scoprrrrus)and others as included on the DOE listing of non native invasive species. 2. Increase the overall cover of naxive trees and shrubs. 3. Increase the native plaut species diversity. 4. Restore the area affected by water line constn�ction. As fmal project design plans are prepazed a final mitigation plan will be prepared. This plan will include details as required by the City of Newcastte. 0 Coristruction plan ❑ Planting pian showing details of plant numbers, species and spacing Project No.20104 Page No. 10 Mr. Steve Beck i Nrnrember 7, 2005 Revision December Z, 2005 ❑ Monitoring methodology. Monitoring will be carried out over a period of five years foUowing I completion of the work I 0 Standards of success for evaluating tbe success of the project in meeting project goals and � objedives � � ❑ Cornin$encY P� i We trust the inforn�ation presented is sufficient for your curre�rt needs. If you have any questions or require '' addidonal inforniatiation,please call. Sincerely yours, AlderNW � �� " Garet P. Munger Project Scientist Encl.: Table 1 Animal Species Observed or Expected On-Site Figure 1 Vicinity Map Figure 2 Site Map Data Fornu (5) Wetland/Buffer Functions&Values Form , � � Project No. 20104 Page No. 11 TABLE 1 ANIMAL SPECIES OBSERVED OR POSSIBLE ON-SITE Cherie Lane North Renton,Washington Common Name Scientific Name AMPffiBIANS Northwestetn Salamander Ambystoma gracile X Long-tced Salamander Ambystoma macrodactylum X Rough-skinned Newt Taricha gr�losa X Ensarin� Ensatina eschschollzii X Western Toad Bufo boreas X PacifiC Chorus Frog** Pseudacrrs regilla X REPTILES Northem Alligator Lizard Elgaria coeralea X Comtnon Garter Snake ** Thamnophis sirtalis X W. Terrestrial Garter Snake Thamnophis elegans X Northwestern Garter Snake Thamnophfs ordinoides X BIRDS Sharp-Shinned Hawk Accipiter striatus X Cooper's Hawk Accipiter cooperf X Red-tailed Hawk ++ Buteo jamaice»sis X American Kestrel Falco sparverius X Rock Dove ** Columba livia X TABLE 1 (CONTINiIED) ANIMAL SPECIES OBSERVED OR EXPECTED ON-SITE Cherie Land North Renton,Washington �ommon Name Scientific Name BIRDS(Contimied) Baud-tailed Pigeon Columba fasciata Common Barn-owl Tyto alba Western Screxh-owl Otrts kennicottii Great Homed Owl Bubo virginiarrus Rufous Ht�lming}�jt�d +* Selasphorus rufus Downy Woodpecker*# Picoides pubescens Northern Flicker •t Colaptes auratus Pileated Woodpecker Dryncopus pileatus Western Wood Pewee Contopus sordidulus Willow FlyCatcher Empidonax traillii Hammond's Flycatcher Empidonax Irammondii Pacific Slope Flycatcher Empidonax di,fj"icilis Tree Swallow�* Tacirycinela bicolor V'iolet-green Swallow Tachyci►reta tha/assirra N. Rough-winged Swallow Stelgidopteryx serripennis Cliff Swallow Hirundo pyrrho�ota Baru Swallow"• Hirundo rustrca Steller's Jay** Cyanocitta ste!leri AmeriCan Crow«* Corvus braclryrhynchos Black�apped Chickadee#* Parus atricappilus Chestnut-backed Cluckadee Parrrs rafescens , Bushtit ** Psaltriparus minimus Rai-breasted Nuthatch+'' Sitta canadensis Brown Creeper ** Certhia americana Bewick's Wren*� 77rryomanes bewickii Winter Wren#* Troglodytes troglodytes Golden-crowned Kinglet Regulus salrapa Ruby-Crowned Kinglet Regulus calerrdula Swainson's Thrush Catharus ustulatus Hermit Thrush Catharus guttatus American Robin** Turdus migratorrus Varied Thnish Ixoreus naevius Cedar Waxwing ** Bom6ycilla cedrorum European Starling ** Sturnus vulgaris Solitary Vueo Vrreo solitarrus Hutton's Vireo Vireo huttoni TABLE 1 (CONTINUED) t�NIMAL SPECIES OBSERVED OR EXPECTED ON-SITE Cherie Lsne North Renton,Washington Co�Qn Name Scientific Name BIRDS(Co�inued) Warbling Vireo Vireo gilvus Red-eyed Vireo �reo olivaceus Orange-cmwned Wa�ler Vermivora celata Yellow Warbler Dendroica petechia Yellow-rumped Warbler++ Dendroica coronata Black-throated Gray Warbler Dendroica nigrescens McGillivray's Warbler Oporornis tolmiei Common Yellowthroat Geothlypis trichas Wilson's Warbler Wilsonia pusilla Western Tanager Pira»ga ludoviciarra Black-headed Grosbeak Pheucticus melanocephalus Rufous-sided Towhee** Pipilo erythrophthalmus Song Sparmw*' Melospiza�nelodia White-crowned Sparrow ** Zonotrichia leucophrys Dark-Cyed Junoo ** Junco hyenialis Red-winged Blackbird Agelaius phoeniceus Brown-headed Cowbird Molothrus ater Purple Finch Carpodacus purpureus House Finch •* Carpodacus mexicanus Pine Sisldn Carduelrs pinus American Goldfinch Cardue/is tristis Evening Grosbeak Coccothraustes vespertirrus House Sparrow ** Passer domesticus 11ZAD'II1�lI.,S Common Opossum Didelphis virginimra Trowbridge's Shrew Sorex trowbridgei Vagrant Shrew Sorex vagrarrs Dusky Shrew Sorex obscuras PacifiC Watez Shrew Sorex bendirei Shrew-mole Neurotrichus grbbsi Townsend's Mole Scapanus townsendi Pacific Mole Scapa�rus orarius Little Brown Myotis Myotis luciJugus Yuma Myotis Myotis yumaensis Long-eared Myotis Myotis evotis TABLE 1 (CONTINUED) A1vIMAL SPECIES OBSERVED OR EXPECTED ON-SITE Cherie Lane North Renton,Washington Common Name Scientific Name bZAMMAIS(Continned) Eastem Couontail Sylvflagus floridanus Mountain Beaver Aplodontia rufa Townsend's Chipmunk Eutamias townsendi Eastem Gray Squirrel** Sciurus carolinensis Douglas'Squirrel Tamiasciurus douglasi Dcer Mouse Peromyscus maniculatus Bushy-tailed Woodrat Neotoma cirrerea Oregon Vole Microtus oregoni House Mouse Mus musculus Rac000n ** Procyon lotor � Short-tailed Weasel Mustela ermrnea � Long-tailed Weasel Mustela frereata SViped Skunk Mephitis mephit�s Coyote Cattis latrans Notes• ** Species observe�on property,including visual sightings,vocalizations,or indirect evidence such as tracks,burrows, nests,or scat. Wetland/Buffer Functions & Values Form Cowardin Class: Forested Local Rating: _2_ Wetland size: - Date: Occurrence Principal Function/Value Y N Kationale Function s Potential Im act from Buffer Avera>in Y Flood Flow Alteration Y Wetlands are on slope limited capacity Buffer averaging will not affect capacity for to retain surface water. retention/detention in wetlands. Sediment Removal Y Wetland does not have surface Minimum 2Sf} buffer along with stormwater connection with other waters. treatment system will limit sediment transport to wetlands. Nutrient & "Toxicant Removal Y See sediment r•emoval comments See sediment removal comments. Erosion Contr�l & Shoreline N Stabilization Production of Or�anic Matter Y Wetland does not have connection with Opening up adjacent upland allows more sun and its Ex ort other waters and more bio roduction in buffer& wetland General Habitat Suitability Y Wetland has relatively low species and Buffer averaging will not reduce habitat area structural diversit be ond that rovided with uniform SOft buffer. Habitat for Aquatic Y No flowin� water soils remain saturated See comments for general habitat suitability. lnvertebrates to rovide habitat Habitat for Amphibians Y Limited ponded surface water for egg la in r Habitat for Wetland-Assuciated N Area is small no open water or flowing Habitat area not reduced beyond that pi'ovided Mammals water for wetland associated mammal with uniform SOfl buffer. habitat Habitat for Wetland-Associated N �3irds General Fish Habitat N Native Ylant Richness Y Buffer averaging will not reduce plant species richness. Total habitat area is not reduced. Educatiorial or Scieniific Value Uniqueness and Heritage Wetlands are not unique in area DATA FOR�-I ROUTINE ON-SITE �i�'ETLAND DETERtiiI'V:�TION Describe General Site Mixed decid:toiss jorest Data Point No.: DP-1 Conditions: Site Disturbance? Sewer line through middle of propern' Location: See site Map VEGETATION o ;� � o �, � Dominant Plant Species � � � Dominant Plant Species ? � � •. �. � � f � � f 1 Svm horicar os a(ba Fnc(� S 8 2 Gaultheria sha!!on Cpl S 9 3 Polvstichum munitum L'p/ H ]0 4 Corylus cornuta Cp! S 1 1 5 Fraxinus lntifolia Fac6�' T 12 6 13 7 14 Percent of dominant species that are OBL, FACW, and/or FAC: '�`'G Is the hydrophytic vegetation criterion met? ��'o Rationale: Less rhan�0%species hydrophvtic SOIL Soil T��pe: .-11dern�ood Hydric Soils List: :�'� �' Histic Epipedon? .�'o Mottles? :�'o Gle}�ed`:' ��'o Matrir Color: 10}R-J%2 Mottle Colors: - Depth: IZ" Other hvdric soil indicators: :�'n Is the h��dric soil criterion met? :�'o Rationale: Chronta 2 wrrhour n:orrle.� HYDROLOG�' Is the ground surface inundated? :�� Surface«�ater depth: - Is the soil saturated? :��'ot in upper 18" Depth to free-standing�vater in probe hole: :�� Other field evidence h��drolog��: :�'� Is the�vetland hy�drology critcrion met? .�'�� Rationale: :�'on hv�lrre sorl. ,1'o x�nter table rn crpper 1�3" WETLAND DETERVIINATION Are��ctland critena met'� .�'�� Rationale for«etland decision: :��n hv�lrrc.�orl, nnx 12t��lropfrvtrc i�et�etastion, rir�.snrl cntirrntrrm Project Name: Cl�erin I.,arre:\'nrth AtderNW Ficld Im�cstigator(s): �� ft�n�'Er `1 R \orth �9th Strcct Project No.: 2010� Date: -�-f-�; S�attic. ��zshington 9R 1()3 D�TA FORM ROUTINE ON-SITE WETLAND DETERMINATION Describe General Site Mixed deciduous fore.rt Data Point No.: UP-2 Conditions: Site Disturbance? Sewer line through middle of properry Location: S'ee site Map �'EGETATION o �, � o � � Dominant Plant Species � � � Dominant Plant Spccics `�° � b c ..- � :� � z., `� v� � �' ;n 1 S m horicar os albn FacL' S 8 2 Populus bnlsamifera Fnc T 9 3 Ranunculus repens Fac4[' H 10 4 Fraxinus lati olia Faclb" T 11 5 12 6 13 7 14 Percent of dominant species that are OBL, FACVV, and/or FAC: 66% Is the hydrophytic vegetation critenon met'? yes Rationale: :��ore rhnn SO%species hvdrophyric SOIL Soil Type: _=11�lenti�ood Hydric Soils List: �� Histic Epipedon? :'�'o Mottles? �'o Gleyed? �'o Matrix Color: IOYR�t%2 Mottle Colors: - Depth: 1�„ Other hydric soil indicators: :�'� Is the hvdric soil criterion met? Yes Rationale: Chron,a?wrth mot£le.s HYDROLOGY Is the ground surface inundated? -�'� Surface �vater depth: - Is the soil saturated? Sasturnted at 6" Depth to free-standing �vater in probe hole: '�" Other field evidence hydrolog}�: l"es Is the wetland h}�drolog}� critenon met'' t ES Rationale: Jt'nter�nhle r,a t�pper /h'" WETLAND DETER:V1I�iATIO\' Are��ctland critcna mct? t"Es Rationale for w•etland decision: Pn.ci�it'e lnrlicnror.e Ji�r ench pc7rnnieter Project Name: C'heri�l.ane 11 AlderNW Field Investigator(s): G. :llunger �18 North >9th Street Project No.: ?010� Date: �-h-�? Seattle, Washington 98103 DATA FOR1�1 ROliTINE ON-SITE WETLAND DETER:�iINATION Descnbe General Site Niixed deciduous forest Data Point No.: DP-3 Conditions: Site Disturbance? Sewer line thro:�gh middle of propertv. Location: See site Map VEGETATION � E .� � Dominant Plant Species � b � Dominant Plant Species `�° � �o -� � b � c `� � c � ;�; 1 Svm honcar os alba FacG' S 8 2 Rubus discolor C pl S 9 3 Polvstichum munitt�m C'pl tl 10 � Popirlus balsamifern Fac T 1 I 5 Fraxint�s lati olia FncbG' T 12 6 13 7 14 Percent ofdominant species that are OBL, FACW, and/or FAC: �p°� Is the hydroph_y�tic vegetation enterion met? ��'� Rationale: Less thnn �0%specie.c hydrophvtic SOIL Soil Type: :;ldern�ood Hydric Soils List: -�'o Histic Epipedon? :'�'o Mottles� ��'o Gle��ed? No Matrix Color: ?.SY�i3 Mottle Colors: - Depth: 12" Other hydric soil indicators ��'� Is the hvdric soil criterion met? :�`o Rationale: Chronra?wrthout mottles HYDROLOGY Is the ground surface inundated? �� Surface��ater depth: - Is the soil saturated? :Vot in upper 18" Depth to free-standing �vater in probe hole: :�'� Other field evidence hydrology: =�� Is the�y�etland hvdrolog�- enterion met? :`�� Rationale: .�'��n hy�Iric.corl. :\'o �t•nrer rable in upper IS" �VETLAND DETERiVIINATION Are��etland criteria met'? .�� Rattonale for�tietland deCiSlon: :Ann hvdric.�oil, non hvdropht�tic ve��etcr.stion, rrr.soiJ saturntrnn Project Name: Cheria Lane :�'orrh AlderVW Field Investi�ator(s): G. :1lun�er �l 8 Vorth �9th Street Project No.: ?010-! Datc: �-h-OS Scattic. �'�'ashington �)8103 DATA FORM ROUTINE ON-SITE WETLAND DETERNII'.VATION Describe General Site Mixed deciduous /�oresr Data Point No.: DP-� Conditions: Site Disturbance? Sewer line through middle of propertl�. Location: See srte Map VEGETATIOV oN � o �, � Dominant Plant Species � � ; Dominant Plant Species � � � �..+ �„ :.� �., C �' C%� � � � 1 Cornus stolonifera Fac�' S $ Z Rubus discolor L'pl S 9 3 Phnlaris balsamijera Fac6i' H 10 4 Populus balsamijera Fac T 1 1 5 Fraxim�s lati olia Fnc«' T 12 6 13 7 14 Percent of dominant species that are OBL, FACW, and/or FAC: �4% Is the hydrophy�tic vegetation criterion met'? Yes Rationale: _1 fore thnn SO%specres hvdrnphytic SOIL Soil Type: Alderwooc� Hvdnc Soils List: �'� Histic Epipedon? :'�'o Mottles'? �'o Gleyed? :�o Matrix Color: 2.SF�t%7 Mottle Colors: - Depth: 12" Othcr hvdric soil indicators: ��'� Is the hvdric soil criterion met'? r"es Rationale: Chroma 1 without nrottle.s HYDROLOGY Is the ground surface inundated? :�'o Surface��ater depth: - Is the soil saturated? Below�l" Depth to free-standing ��ater in probe hole: �" Other field evidence hydrologti,: -�� Is the«•ctland h}drology criterion met? ves Rationalc: titi�nrer rnble ar 6" �'�'ETLA`D DETERVIIN�TION Are«etland criteria met'? ��E.s Rationale for�t�etland deeision: Posilrve r�7�lica�nrs fc�r enclr parnrrreter. Project Name: Cherra I.ane:�'orrh �IderNW' Field Investigator(s): G. :thrn�er �I 8 '�orth �9th Street Project No.: 3010-t Date: -1-6-OS Scattic, ��'ashiugton 98103 D�TA FOR1��I � ROUTINE ON-SITE WETLAND DETERNIINATION Describe General Site Mixed deciduous forest Data Point No.: DP-� Conditions: Site Disturbance� Sewer line through middle of properry. Location: See site Map VEGETATION o �, � o � � Dominant Plant Species � � � Domina.nt Plant Species ? � � v � f � � � � � � 1 Frazinus lati olia Fnc6i' 7' 8 2 Rubus discolor C pl S y 3 Phalarrsbalsamifera Fac�i' H IU �3 Symphoricarpos albus FacC' S 1 I 5 12 6 13 7 1� Percent of dominant species that are OBL, FACW, and/or FAC: 6640 Is the hydrophy�tic vegetation criterion met? Fes Rationale: .�fore rhan SO%species hvdrophvric SOIL Soil T}pe: ��lldern•ood H}�dric Soils List: .�`� Histic Epipedon? ,'�'o Mottles? :�'o Gleyed? =�'� Matris Color: 2.SY-1i3 Mottle Colors: - Depth: 1?" Other hvdric soil indicators: .�'�� Is the h�dric soil criterion met? -�'o Rationale: Chronta 3 HYDROLOGY Is the ground surface inundated? ��'� Surface��ater depth: - Is the soil saturated? .�ot in upper 12" Depth to free-standing water in probe hole: 16" Other field evidence hydrology: :�o Is the«�etland h��drolog�-criterion met? no Rationale: ti��arer rable helox� 13" W'ETLA�D DETERMINATION Are�retland critcna met? n�� Rationale for«�tland decision: �'nn hvclrre sni(n•nter lei e!heJnit� 1?" Project I�tamc: ('l�erra I,nne .�nrth �IdCrN��' Field Investigator(s): ��. :�/t�nger �1� North �9th Strect Project No.: J010-1 Date� a-6-0� Scattic, ��Vashington y8103 Cherie Lane North "� 7� �� _ ``� �~ti .-� �' ��4 � �``\ `.•,� � .r. ,� � ,f — r• � o � r i ,� 7°� �;� `s 30�_�+cT �� ,q , ; �.� � '_ � ! �� J�ll 1�� ';t� ' i `.` f - ,C� , , N— s ' - �` �t1 '`l h N — I tn I ), I "'-� 'Z � � '--_- N_._`�" n_S=31 ST_ST �`-.__S:3137=CT� � � �� - ,/ � , � --�,�'., �� ;�� ,N � ! � ` W � ; y ` ti E I I � a' S_32ND_PL �, �S_32ND_PL '�-� ` _ —T--�---. �� aj y ; W 1 ; �� ; Q � i �' __--___ �Vj; 1 1 � J Vl W ~� ---_r�.r+�� --_---5_32Nd_ST-L3 � � Q �r 2 i y `------- /// I ( ;; p S�,a. I � � � � ..H- T —�w-- - - - ��_.T___�> � .� ;; ; Q• D i i� Z ,,,� r. � i � � � , ,� � W � � � 5-35'�'�-5j=� ; I ;O -—-- d' �ti c v� - � � i�/ � o� '- � S_34TH_ST --- w � i r` ��— V--'�� N 1 � �r lh D :_ ------ -___� J! � � . ` �1 - -ST ___..:. -. _ � � � � �:=S_36TH_ ._ I N ` � '� � �� , i � I --.__ tn n� _\, _ / h �� ` ,t /�r ` �� .-.:-� ---•�,/ � � l I''l � ' _ �_-------.',� � �i'.�� ' '.�-_..Lr,LSL36T.H�PL_--=-~ � � �' � SE 1�aJH-ST 5_37TH�ST d! -'- _ I S'3�Tk.:S7 � _� �/._:._ Ic}�em K,�w ca...tr i: �,-----�-r 1 � / � I . r---��-�-1 , � , � �_"`_`--r-� 0 �- 551i1� � dI VICINITY MAP A L D Cherie Lane North E R N Renton, Washin ton W 9 Project No.20104 Date Nov., 2005 Figure 1 � �- I - T � I I I ! TRACT D I ' z 3 � \ 13 \ , \ . \ • ,wr x \ �oc ' i� w�r��c wrec ND TRACT 'C� I 4 . 21 SF wn x WETL D X • 13.988 ww ix \ �FILYq Y '� ` . NN Buffer Increcse Areo 9,812sq.ft. �.�X �x � _ � � � . ,„„.,� �,� I ' '�X � � • 1 Buffer Re�uction Area 7,��5sq.f:. � I �� .j �' !I Restore {ollowing Water � i ' line constructior 3,030sq,ft. \ . � '� - �• � I ET NTIO � • 2 3 RA 1 wN ee � 1 f � ,�.� WET p ,.. B; • DP I � ApP�ox�mote Daic Poin; Loca!ion I �� 8 Os .ft. i � , I � i � � � � i f APPROXIMATE SCALE ' 60 0 60 120 feet 5. .S1ND STREET � --�- _,� I� i I � ✓I J5 � 6 � � $ 9 10 ! I I � I � i I � � � i I �j � � � I I • o � � ''\1 • 5 � �1� . I � � ! � ' . . 6 + (� 2 �l. � ,,,,n_a .�s� I • • , • .ww. j C , .�-� � Q �� I WETL TR CT "A"' � 3 . 9 •� TRAC'f° ,722 SF 7 I� � Q1yETLAN 6,072 Sf _ ' i � . wc*wo'�• ;, •r J "N_: —�� I _�9 • i � � � """-' I S. 34 TH ST . . • �rw-, �w-ao (n �-' • �a � 1 ' MI/-I9 w � �1 � I ,WII-1B �� 1 �-1e MM-I � I �`\ . r , .J �-I`��.A. I ' � II �� : �� 1 �-'6 \ . I � � �� il , � � '1 � \ 5. 347H L, 1 S. 34T'r/ P�. I I � � �: � S ITE MAP Cherie Lane North � � Renton, Washington Proj. No. 20104 Date Nov., 2005 Figure 2 PLANT LIST �Ymboi Scientific Name Common Name Size Ce Thuja plicata Western Rsd Cedar 2' -3' He Tsuga heterophylla Western Henilock 2'—3' osier Cornus stolonijera Red-osier dogwood cuttings rose Rosa gu�nnoccrrpa Wild rose 2ga1 �, Hn Corylus cornuta hazelm�t 2ga1 Ap Pyrus fusca Crab apple 2 gal salal Gaultheria shallon salal 1 gal Additional native species may be included in final planting plan. Planting densities will be adjusted in the final planting plan. � � � ;� � � � � . � • . �,, � . I . ANW 9C , 1� + Mk tOC � �1� I � i • ' �Nw „c nrrw ac a . U� t� ' , ND TRACT "C�� ', � 4 , 21 SF y \ WETL D ~ ' • 13,988 F � a 1 � � ANW 12C � WETIANp 'C' 6C O� l � a , � � � •1 . � O �� • �� $� � • �� . �ww �3C nNw 2c • O � 1* ANW aC I O I ANW iC II ' � � S •� ' OANW 3C � O O ` a I , � � B' O I O a �y'' � O O °' ,��'v�' a O I . � � � �. s. O � yy• � � y y► '• �ra,► � ��,W rs�' � t � � i � • r + � ' . • I � i1 • 1 , ' � i �` • I • 1 ET NTIO .� � 2 3 � �� • �� RA T 1 . ar,w sa � , � � II iww ,s � �• '�, � �, � ` ' �WET D NW �� ' '�, � � � 8 Os .ft. • � ANW 38 ANW 28 � � I i i / � �� I ` ' , i \ S. 34 i H ' L. APPROXIMATE SCALE ' 50 0 5Q 100 feet � - - - - i � � . , a ' � • .iv' I • �� /� � '� / . � , ` • � � A�_5� i • y,NW_8 '�-----�� I , Q� �I , • �ANW-4� �, , '' -� I i a �� . ETL T CT "A" ' � �, a TRA�"'fie 0.722 SF g. 1 �� O 'vYETLAv 6,072 SF Nw- G � O . w�uN� 'a' a a � � ANW-2 H� ' - �. � � - 1� • �y�► � y ANW-1�-9 � � ; . � '1 a� H' �'O � '' °' i . �ww-, nri o � ��"p w �� . °� / � Oa �� ww- �ww- y� �y.• � 1�H� I _�8 N�-� • � � 8� i a WE':AND �A' • I - JI � f ' O �`� � G ANN'-15 l�yJ a �� .� � � �,� m � - E 1 a '�� a � � O�� 1\ � \'� BUFFER ENHANCEMNT/MITIGATION CONCEPT Cherie Lane North � � Renton, Washington Proj. No. 20104 Dote Dec., 2005 Figure ..3 Appendix 2 AlderNW — Wetland Evaluation/Buffer AveragingPlan Concept June 7, 2006 �� i)�U-4; 1i��tland Il��lr.�le�� Keport_fi-�i�?-1 duc A1derNW .1une 7, 2006 Pcoject No. 20104 ! Mr. Steve Beck 19129 SE 145th Stre�t Reaton,Washington 98056 Subject: Wetland Evaluation/Buffer Averaging Plan Concept Cherie Lane North South 34�Street at Wells Avenue R�aton,WashinStan Paroel#'s 2923059188 and 2923059040 Deaz Mr. Beck: As requested, we have conducted a wetland evaluation for the property proposed for developme�as the Cherie lan�e North residential d�velopment. It is located near the intersection of�Wells Avenue South and South 34th Street in the City of R,enton. Tl�e location of tbe subject parcel is shown on the attached Vicinity Map (Figure 1). The purpose of ow work was to ideutify the limits of the we�(and areas an and immediately adjacent to the subject property. We ha,ve also reviewed Site Developmeat plans prepared by Schweikel and Associates, Inc., dated Ju�, 2006 to identify , project impads and prepare a buffer averag�ing plan. In conducting our site wetland evaluation, we followed the general procedures for the routine on-site methodology as outlined in tbe Washington State Wetlands Identification and Delineation Mam�al(March 1997). This proce�ure invalves analysis of vegetation patterns, soil condirions, and near-surface hydrology in making a detemunation of vve�tlan�d«�anditiams. � Our s�ope of work included site visits in April, 2005 to complete the wet]and evalualion and flag the limits of the site wetlands and in October, 2005 to review site conditions for preparatian of this report. We had also made a preliminary site visit in May, 2044. The flagged wetland points have be�surveyed and plotted on project maps as shown�project design plans by Schweikl a�Associates, and on the Site Map(Figure 2). We revisited the site on May 7, 2006 to reexamine the wetland delineatiion after receiving review comments from The Watershed Company in their le�ttter dated May 3, 2006. At that time the wetland limits were reflagged. The new limits have been surveyed by CORE Design and have been plotted on project maps. WETLAND EVALUATION PROCEDURES For the purpose of this study, we used the wetland definition adopted by the Environmental Protection Agency(EPA) a�the Army Corps of Engineers(COE) for administering Section 404 of the Clean Water Act. According to this definitioq wetlands are: 518 North 59�h Street, Seattle, Washington 98103• Phone (206)783-1036 email aldernwC�comcast.net Mr. Steve Beck June 7,2006 `�fhose areas that are inundated or sahuated by surf�ce water or groundwater at a frequency aad duration sufficient to supPort, and that under nornial circumstances do support, a prevalence of vegetation typically adapted for life in sa�rated soil conditions. Wetlands generally include swamps,marshes,bogs,and similar areas." (33 CFR 323) In Washington State, the Shoreline Management Act and Growth Manageme� Ad have amended ttris definition to exclude some wetiand situations by adding the following sentences to the wetland definition: Wetlands do not include those artificial wetlands inteMionally created from non-wetland sites, including but not limited to, irrigation and drainage ditcities, grass-linod swales, canals, detemion facilities, wa�stewater treat�nent facilities, f�rm ponds, and landscape amenities, or those wetlands created af�er July 1, 1990, thai were inteationally created as a result of the construction of a road, strcet or Highway. Wetlands may include those artificial wetlands intemionally created from non- wetland areas to mitigate the conversion of wet(ands. Delineation procedures are based on diagnostic eavimnme�al indicators of wetland vegetation, vveklan�d soils, and wetland hydrology. These procedures, ouflined in the Washington State Wetlarrds Identification and Delineation Manual (March 1997) are comanonly l�own as a Triple Parameter Method. By definition, an area is designated as wetland when there aze positive indicators for all�parazneters. A listing of plaat spacies has been developed for use in the methodology for delineating wetland areas. This listing assigns plant species to one of five indicator status categories ranging from Obligate wetlaad species, which ahnost always occur in wetlands, to Upland species, which rarely occur in wetlands. Under normal conditions, hydrophytic vegetatian is determined to be pr�sent if more than 50 perc�ent of the dominant species are in�e Obligate (OBL), Facultative Wetland(FACVV), or Facultative(FAC)indicator categories. Diagnostic indicators of hydric soils are related to soil satwation, wluch leads to anaerobic conditio�s in the soil. Under these conditions, decomposition of organic material is inhibited and soil minerals are reduced, creating characteristic soil colors �at can be qua�tified by oomparison with Munsell Soil Color Charts. A chroma of one or less in unmottled soils or a ctiroma of two or less in mottled soils generall}�'indicates a hydric soil. In addition, soils ihat are saiurated during the growiag season satisfy a criterion for hydric soits. We used a hand auger and or shovel to collect soil samples from depths of 8 to 18 incbes, or below the A horizon. Wetland hydrviogy is defined as inundated or saturated soil oonditians for at least 14 consecutive days during the growing season. If no water is prese�at the time of evaluation, onher indicators may include topograp}uc low poiats or chaimels,flood debris, complete absence of vegetation,or presence of hydric soils. GENERAL SITE CONDITIONS The subject property is an approximately 3.4 acre property located in the 3400 block of Wells Avernie South in the City of Renton, as shown on Figure 1. South 34d� Street right�f-way nu�s through the middle of the property, At present the property is undevelaped. The area included within the project includes two pazcels; 2923059188 (1.8 acre); 2923059040(1.2 acre); and the unopened South 34`�Street right-of-way(.4 acre). Project No. 20104 Page No. 2 Mr. Steve Beck June 7,2006 �l� P�es to the east and north of the project are occupied by existing single family resideaxxs of the Wins�r deveiop�. A new �+eside�ial �, Cherie Lana is �mder oo�sdudion � the ptoperiy to the south. Tl�e site is occupiad by a mixed co�ifer-decic�ous forrst stand of cvmposod of mostly deci�ous Vees. Or+�gOn ash (Fiaxara�s latifolia), rad al�er (Abr�cs r�bm) bladc c�t0oawood (Populus balsamifera), and big leaf maple (Acer macropieylluin) aze the cro�mon decidua�us trees species �tl�e prnpecty. Westsrn red c�edar(Thu,ja Plicata) is the common c�onifaer hee pr�t o�n the propert.y. Salmonberry(Rubus spectabilis), snovvberrY(S.YmP�ri��Q�J, ha�ednut{Corylus�rnuta),and I�'m�alayan blackberry{Rubus discolor)are�shrub species p�t There are � sanitary sevwer a�d starm drain P�pes fnllow�n8 the alignmeut of the Sa� 34t� Street right�f- way. These pipe lin�s wez+e installed so�ne af�er 1996. Ca�nstructian of the pipeli�s resulted in disturbance to tl�e srte in an approximately 30ft wide strip,in an east west orientati�through d�e property. So�7s across t�e praperty and on much of the s�urrouading area ane mapped as Aldervwood gravelly 5andy loem(Soil SurNey of King Coraity, Washington, U.S. Soil Ca�servati� Service, 1473). The Aldervvood seric;s is made up of �+we�l-dcained soils t�at have a weakly to stroogly oo�solidated subsaratum at�of between 24 and 40 �ch�. The National Tec�hnic,�l Comm�ittee £nr Hydric Soils �oes nat list the Alderwood serie.s as a hydric soil alth�gh vweNand oonditi�are oo�mon in depressional areas witLh�Alderwood soil umts. T'here has been coal mining activity on praperties to the south. There may have been some work related to the coal �8 �tY�� P�Y- Surface soils at so�nne lacatia�ns on the property s6aw evide�ce of the pa4t adivity, and inciude so�ne ooal mine tailir�s. Our site observa�ions aze not c�nsisoeat with t�►e Alderwood sail type �- �F��8��Y�Y�Plain the differeaces wher�preseat. Topograplucally, the property generally slopes down from about elev. 220 along the eastern property line to the low pourt of about etev. I 82 on the southwest property comer. . `�VETI.AND AREAS �.. We have ideatified the limits of thrce vuetland areas on the property as shown o�tl�e Site Map(Figure 2). A pr�,wious sd�dy datod S�ber 24, 1996, by B�vveh+�e A�ssoci�s, Inc. ideutified two vuetland ar�eas on the Property "ILe configuration of t}� wetiands icientified in tl�ir ceport is similar to that ide�tified during th�e r�eceaR work. Over ibe nine yea.is sirmce tt�eir sludy was c�npleted t�ei+e has bee� consicierable new development adjace� to �e subject PT�P��Y and the c�nstruc� of the sanitary sewer ancl storm drain pipe li�s across the Properh'. This vwork has appareatly a�ected surfaoe and subsurface drainage pattems on dye.P�Y, �8 in change in the vv�land co�figuration. Vlretland A with an area of approximately 6,230sq.8. is located across the east end of the property. Wetland B is a small area near the south property line and west of the south end of Wetland A. Wetland C with an area of apProximately 25,OOOsq.ft is the lazgest of the site wetlands. Each of ihe site wetlaads is an isolated area with no defined surface inlet or outlet. Project No. 20104 Page No. 3 I 1VIr. steve Beck June 7,2006 'I7�e wetland delineation was reviewed by The Waiershed Company as reporbad in their letter dated May 3, 2006. The wetland limits as show�n on praject maps reflect adjustinents in accordance with their G�nme�rts. As a result of their review,the area of Wetland C has bcen enlarged. The delineation of We�lands A and B did nat change. W swd A Wedand A is an isolated wedand located on the east�d of the property. Vegetation within the wetland includes an overstory black oottonwood and western red cedar. Understory shrub species inctude salmonberry, Himalayan blaickberry, and red osier dogwood (Cornus stolonifera). Rced canarygrass (Phalaris arundinacea), soft rush (Juncus e,�iesus), and creepiag buttercup(Rarrurrculus repens)are herbaceous species within the wetland. Using the U. S. Fish and Wildlife Service wetland classification system (Cowardin et a1., 1979), the wetland is designated as a palustrine forest wetland habitat. Hydrologically this wetland is supported by seepage into the noitheast end of the area. At the time of observations in April, 2005, there was surface drainage entering the w�land fiom the existing developme�t to the east. This surface water moved south thraugh the wetland and dissipated over the sou�end of the azea. It is our i�erpretati�on that the wetland would satisfy the criteria for designation as a City of Renton Category 2 wetland. The standa.rd buffer for a category 2 wetland in the City of Recrton is SOft. Wetlsnd B Wet]and B is a very small isolated wetland of less than 1,OOOsq.ft,located along the south property line. It is situated vvithin a shallow depression with no defined inlet or outle�. During an initial site visit in April, 2005, soils within the wetland were saturated to near the surface altr►ough there was no standing surface water present. Vegetation within the w�etland includes black cott�wood and Oregon ash fornung a canapy over the wedand, with red osier dogwood and Himalayan blackberry as shrub cover. Herbaceous species presern include reed canarygrass (Phalaris arundinacea)aad crther grasses, soft rush (Juncus e,fficsus), atyd creeping buttercup(Ranunculus repens). It is our irnerpretation that the wetland would satisfy the criteria for designation as a City of Renton Category 3 wetland. As a small isolated wetland of less tl�aan 2,200sq.ft. the area can be filkd, if mitigarion is provided. Mitigaiion can be provided with storm water tre�trnent and or la�scaping. Mitigation for filling Wetland B is being partia(ly pmvided by tlie storm water treatment system for the project. Additional mitigation for the habitat area of the wetland and buffer is being provided in the buffer averaging design whereby an additionai approximately 7,OOOsq.R of upland habitat area is being set aside form develapment beyond that which would be provided with the uniform SOft buffer. Wetland C Wekland C is the largest of the site wedands, having an area of approximately 25,OOOsq.ft. It is locaied on the northwest curner of the property. Vegetation within the wetland includes Oregon ash, black cottonwvod and some western red cedar (Thuja plicata) traes. Un�rstory shrub vegetation includes Himalayan blackberry, snowberry and, salmonberry. Herbaceous vegetarion inciudes, reed canary grass soft rush. Using the U. S. Fish and Wildlife Project No. 20104 Page No.4 Mr. Steve Beck June'1,2006 Sen►ice wetland classification system(Cowardin et al., 1979),the wetland is designated as a palustrine forest wetland habitat. Hydrologically, the area is supported by groundwater seepage. The interior topography is somewhat hurmnocky, creating sc�tered law areas. At the time of our observations in April, 2005, there was shaIlow surface water in isolaLad depressions. There is no defined surface inlet or outlet for the wedand. It is our interpretation that the wedand satisfies the criteria for designation as a City of Renton Category 2 wetland. Tbe standard buffer for a category 2 wetland in the Cifiy of Renton is SOft. Previous Wetland Studv There have bcen two pnwious wetland sdidies addressing wetlaciids on the Cherie La�ae North projed and in � immediate vicinity. These include a study by B-12 Associaies, Inc. dated September 24, 1996, w}uch included the subjed properiy and a study by AlderNW dated November 13, 2003, for the Cherie Lane I project imcnediately to t� south. Field work for the B-12 projed was canpte#ed in April, 1996,and field work for the Cl�erie I.ane I project to t�south was completed in April and October, 2003. Field work for tl�e Chcrie Lan�e North project was completed in April aud October of 2004,and in the spring of 2006. The wetland limits on the Cherie Lane North property have undergone cl�znges since the original was comple�ted by B-12 Associates in the spring of 1996. Seven years elapsed atter the B-12 Associates work before the Cherie Lane North field work field work was completsd. Over that time period there ha.ve been significant changes affecting site drainage Pattcros within the property boundaries and on the adjaceQt properties. The identified wetlands are supporte�in large part by neaz surFace groundwater scepage with some coutribution from surface water flows. Soils within the we.�]ands are typically a clay loam wluch is relatively impemieable. Wedand hydrology in the site wetlands can be chardcterized as near surface groundwater seepage and surface water moveat�ent into the upslope side of the wetland wbere it flows across tbe relatively impermeable soils. Surface water in the wetland dissipates throuBh e�vapotransPiration and slow infiltration. Surface water is retained within the wetland in shallow depressions. I As notsd in the B-12 report, tbe subject property and wetlands had been subject to disturbance from past coal mine activities. This was also noted in the wetland report for the Cherie Lane project to the south. With tlris history of site disturbance, near surface hydrology and drainage patterns across the site have bee,n undergoing change. Drainage pattems were altered on the Cherie Lane praperty and on the Cherie Lane North property by construction of roads and activities related to the past mining. Since the B-12 Associates field work was completed, there have been continuing alterations to the site and upslope areas. Immediately to the east of the subject property, new homes have been constructed. This wark involved grading to create building pads and installation of draiu lines azound the homFs. In addition, the sanitary sewer and storm drain line have been constructed along the unconstructed South 34th Street alignment nanning from east to west Project No. 20104 Page No. S Mr. Steve Beck Jwie 7,2006 across the properly. These construction activities on and adjacent to the property have the effect of changing drainage pattems onto and across the property. The level of groundwater reaching the site wetlands likely has be�n reduced. A typical effect of the constivction of ditch lines for sanitary sewers and storm dra.ins is to cr�te subsurface drainage patte�ns along the ba�m of the ditches, and to limit the movement of groundwater laterally across the ditch line. This waild have the effect of reducing groundvvater support to the site wetlands. With surface water being oollected in the storm water treabmeat system, the Ievel of surFace water reactring site wetlaads is likewise alteered. Surface water runoff reaching the site is affected in terms of the location of discharge and in terms of the timing of discharges. Wedands in general and in particular wetlands within developing urban landscapes are dynamic systt�ms. It should be expected that changes in wetland size and position can and will occur over a seven year periad. The general pattern of the site wetlands is similar between the 1996 study a.nd the current study for Cherie lane North, although the exteat of the wetlands is reduced. The extent Wetlands A and C o�n Cherie Iane North is consistent with observations for the Cherie Lane I project to the south. WILDLIFE HABiTAT We have completed a wildlife and habitat evaluation of the projed area, The putpose of our work was to document tbe existing site conditions to ideatify habitats acxi p�ential wildlife use of the property. This work was underCaken to deternune if�ere are critical habitats on the property which would be subject to regula.tion under Renton City C.ale which identifies critical habitats as: ":those habitat areas which mcet any of�e following criteria: i. The documented presence of spacies proposed or listed by tbe federal government or State of Washingtan as endarigered,threatened, sensitive,monitor,or priority;and/or ii. The presence of heron rookeries or raptor nesting areas;and/or rii. Category 1 wetlands(refer to subsection B7b(i)of this Section for classification criteria);and/or iv. Porbions of streams and tl�ir shorelines desigaated in the Reuton Shoreline Master Program, RMC 4-3-090.as Conservancy or Naiural(refer to the Renton Shoreli�Master Program). c. Mapping: . i. Critical babitats are ide�ified by lists, categories and definiti�s of species promulgated by the Wasl�ingtfln State Depar�at of Fisb and Wildlife (N�ame Data SYstem SPecial Anima! I Species) as id�tified in WAC 232-12-011; in the Priority Habitat and Species Program of tbe � Washington StaLe Depart�neat of Fish and Wild6fe; or by n►les and n,g�lations adopted currently or her�a.fter by the U.S.Fish and Wildlife Service. ri. Referenced invecYtories and maps are to be used as guides to tl�e general location and extent of critical habitat. Critical habitat which is identif ed in subsection BSb of this Section, but not shown Project No.20104 Page No.6 i Mr. Steve Beck June 7,2006 on the referenced inventories and maps, are presumed to exist in the City and are also protected under all t�e provisiaos of this section. ui. The actual preseaoe or ab�nc�e of the criteria listod abave as determined bY 9�� professionals, shall �overn the tr�eatm�+nt of an individual b�uildio�g siLe or parcel of fand royuiririg �omplia�e wiiL these�egulafiions." During�e course of site visits to complete the wetland site evaluation we also made notes regarding observation of wildlife species observed on the site. The subject properi.y is occupied by ooe general vegetatia�n cover type. Lowland mixed fnr�est is the predo�ninant v�on aover type ac�+oss ti�e property. "Ibis cov� type is based on 1Le habitat c�tegories liste� in the King Couuty �Idlife Study GuideHnes for SEPA (1993). Similar cate,go�ries are listod and d�scribod in the Kmg CvuntY �ldlife Habitat Profile(198�. The majority of tlie property is occupied by s�ond or third growth mixed fnrest with variation in the relarive cover by oanifers and deciduaus t�e.s. 'Ihe forest cover on the soumern portioa of the P�T�Y�8�Y�b3' deciduoos t�+aes primarily bladc oo�bonwood and Oregan asb. On the northexn sedion of the property, traes pn�seat include vv�rn red vedar. � We have prepazed a listing of wildlife species (Table 1) observed or likely to be present on the property. This listing is based an species occurrences natad in King County Wildlife Nabitat Profrle(1987)and on persanal exQerience. A�nphibicros and Reptiles Odier than the Pacific chorus frog (Pseudacris regilla), no amphibians were encou�ered during our site visits. A�ians and iepRiles are �sity inat�ive during fall and vvi�er and at+e a�oet fi�aqueatly eacaouIItered duriog SPrinB and summer. Tfie oov�er types on this P�P�Y,P��Y the fio�+e.stsd wetland and ad,jaoe�seca�d-gravvti� ferest, s6ould provide habitat f� several species of amph�bians. 'Ihe most likely species ate t6e northwesbem salamander (.lmbystonaa gracile) and laag-toed sala�mander (Anlbysto�na miacm�dacrylum). Tt�e pre.4eace of amphibiaas aai the site is limihed by the abseaoe of areas of standing water which might provide breeding habitat for a�hibians. The most likely rep�les to be found in the habitais avaiiable on this property are the northern alligator lirard(Flgaria coerulea)and gvter snalaes(Thamv�ophis spp.). Table 1 lists ather amptubiaas and reptiles ttrat c�ould be expacted m the habitats prc�ai an t�is siLe. �e species lisbad in Table 1 are ba�9od aa tables provided b3'Ki�Co�tY �198'n for the habitats described above and on our evaluatio�of the exisbing site conditions. Birds Because of their high levels of daytime acrivity and vocalizations, birds are the most commonly encountere�group of verEebrates. Some of the commonly observed spe�ies on the site were the black-capped chickadec {Parus aMcapprlus), American robin (Turdus migratorius), winter wren (Troglodytes troglodytes), and song sparrow (Melospiza melodia). A large number of migrawry songbirds incIuding flycatchers, warblers, and vireos are expected on this site during the breeding season. Project No. 20104 Page No. 7 Mr. Steve Beck June 7, 2006 The most likely raptors to use thi.s site are the great homed owl (Bubo virginiam�s), Cooper's hawk (Accipiter cooperi), and red-tailed hawk(Buteo jcrmaicensis). Table 1 lists od�er bird species expected in the habitats available on this Properh'. Mammals Most ma�nnals t�end to be secretive and nochirnal, and our observations reflect a relatively small proportion of spacies that may actually exist on the subjed property. We observed coyote(Canis latrans) scat on trails around the property. A large nest, probably buih by an eastem graY squirrel (Sciurus carolinensis), was located 'm the fiorest stand aear the north side of the property. Other common mammals that are likely to be present on�e site include opossum (Dfdelphis virginiana), dcer mouse (Peromyscus maniculatus), aad raccoon (Procyan lotor). Several species of bats are also likely to be present in these habita#s during the su�uner. Table 1 lists other mammal species expected to occur in the habita#s availabie on this site. Thmat�ed.Endangered.or Sensitive(TESI Suecie.s Cridcal Habit Two wildlife species included on Washington State listings of TES could be found on or in the vicinity of�e subject pcnperty. 'I'hese include the Bald eagle (Haliaeetus leuc�ocephalus), and pileated woodpecker(Dryocopus pileat�s). Neither of�ese species is listed as threaxened in the state of Washingt�. Bald eagtes ar�e found thnoughout the Puget Sound region. They are most commonly observed along (ake or river shores although they may be found foragi�ng over a large area and may roost in larger tree.s away from bodies of water. No ba(d eagles were observe on or near�e project site. The project site is away from any large bodies of water where they would be likely to build nests. Pile�ted woodpecioers generally inhabit mature and old-growth forests, or second�rowd�forests with sufficieat large snags and fallen t�rees (Rodrick and Milner 1991). Pileated woodpeckers,�re also reported to use open woodlands, parks, and wooded suburbs (Ehrlich et al. 1988) and are regularly seea in those habitats in King County. 'ILey excavate cavities in snags or large dead branches for nesting and usually make a r�ew nest cavity every yeaz. Nest snags are usually greater than 27 inches in diameter and taller than 87 feet. 'Ibere are few large soags within the subject pm�perty which c�ould be used by pileated woodpacioer. During our�Ee visits we did not nde the pr�enoe af aay individuals nor did we note azry trets wit� chazacteristic pilea�od woodpec�Cer foraging cavities. There is not extensive habitat area on the PmperiY or in the near vicinity which is suitable for pileated woodpecker foraging. Great blue herons are nat included on the Wasttington State TES lists although the presence of heron rookeries is ide.ntified as a critical habitat in the City of Renton. No great blue herons were observed on the site during our site visits and there are no heron rookeries in the near vicinity of the project site. Herons are not likely to use the residential habitats on the property and in the near vicinity Red-tailed hawks are likewise not included on the Washington State TES lists although raptor nests are identified as critical habitat in the City of Rernon. There are no red-tailed hawk nests preserrt on or in the near vicinity of the Project No. 20104 Page No. 8 Mr. Steve Be�k Jwie 7, 2006 property. A single red�aited hawk was observed flying over the property during a site visit for the Cherie L,ane I project in April, 2003. Based on our review of existing site conditians it is our conclnsion that there are no critical habitat areas as defined in tl�e City of Rentaa�codes, within or in near proximity to the Cherie Lane North project boundary. PROPOSED DEVELOPMENT—WETLAND IMPACTS It is proposed to develop the appmximately 3.4 acre property for c�onstruction of a 6 lot residential developmeirt as shawn on project maps by Schwe�cl and Associates and an the Site Map (Figure 2). Access to the project will be provided from South 34th Place wtuch has bcen partially completed as part of the Cherie Lane project along the south property line. With the exception of the sinall isolated Wetland B, the site wedands will be set aside fram developmeut within designated Wetland Tracts. As designed, the project will not result in direct impacts to the preserved site wetlands. The tracts include the wedand areas with a minimum 25ft wide buffer, in accordance with provisi�s of the Re.nton City Code wluch allow buffer averaging. Buf�er Width Avera�in� Bnffer width averaging rnay be allowed in accordance with RMC where the following steps are tak�: i. That the wetland coutains variations in ecological sensitivity or there are existing physical improv� in or near the wetland and buffer;and ii. T'hat wi�th averaging will not adversely impact the wetland function and values;an�d ui. That the tatal area contained within the wetland buffer aft�er averaging is no less than that oontained within the required standard buffer prior to averaging;and � iv. A site specific evaluation and dociunentation of buffer adequacy based upon The Science of Wetland Buffers and Its Implications for the Mcmage�rrent of Wetlands, McMillan 2000, or similar approaches have boen conducted. The proposed buffer standard is based on considera�ion of the best available scieace as described in WAC 365-195-905; or wher�there is an absence of vatid scientific inforn�ation, the steps in RMC -�9- 250F aze followed. v. In no instance shall the buffer width be reduced by more than fifty percent(SO%)of the standard buffer or be less than twenty five feei (25ft) wide. Greater buffer width reductions rer�uire review as a variance per subsection N3 of this Sectian and RMC 4-9-250B; and vi. Buffer enbancement in the areas where the buffer is reduced shalt be required oa a case-by-case basis where appropriate to site conditions, wetland sensitivity, and proposed land developme�nt characteristics. vii. Notification may be required pursuant to subsecrion F8 of this Section. Project No. 20104 Page No. 9 Mr. Steve Bedc ]une 7,2006 wetlana bufers aze�egeta#ea uplana areas adjacent to a�a s�ally s��o�nding w�tlands. as such buffers are�y provide bene�Sicial fi�nctions within tbe urbanizing landscape in their realtionship to t�e the wetland and as upland habitai area. They provide beneficial functrions as an element of the preserved wetland and as preserved upland habitat. Bu.,�`'er averaging element(f.) Buffer averaging is being applied to Wetlands A and C. Bo�tLh of these wetlands have been affected by past activities on and adjacent to tt�property. These include coastruction of the water and sanitary sewer lines across the P�n3', construction of the existing residential developments to the north and east, and the developm�t under construdion to �sarth. �activities have involved clearing and grading adivity wiihin tbe wetlands and tt�buffers for t3�e two wetlands. This past activity has affected the majority of the buffer area su,n�oun�ding the site wetlands. The ane se�tion of the buffer wluch was minimally affectsd is on the north end of Wetland A, and off tl�e northeast comer of wetland C,which renoain forested. This forested area is being pree4eerved with the buffer averaging. Bu,�`'er m+eraging elements (ii, iii iv, v and vi) Buffers as an integral unit of the wetland system in urban envirornne�in providing prote�tion to the wetland h�bitat, and in providing what have been ideatified as "sink" and "source"functions. They act to provide protection w the wetland in�e form of Seaeratin8 a Physical bazrier betwcen human activity and the wetland. "Sink"functions are those that in effect, absorb impacts before reaching the wetland. ?hey sen+e to moderate water leve! 8uctuations in the wetland; they serve to mediate chemical and physical impacts to the wetland from erosion, mov�ne�t of seaime,nts and pollutaut into the vwetland;and to moderate tem�esatue in tbe wedand. "Saurce" functioas include the roles served to the we�la�d system to support wildlife habitat, provide biatic i�ut to the wetland system, and for tt�ir role in mediating effiects of human disturbance to vu�ztland associated wildlife. A, These"sink»and"source"functioms are relat,ed to the vegetative cover on the buffer, tt�total area of buffer habitai included,the width of the buffer, sunoundin8�P�P�Y,and the Ievel of development within the surrounding urban landscape. Existing residential development activity on and immediately adjacent to the subject property have affected the effeciiveness of the wetland buffers. The buffer width has beea reduced aloag tl� east si�e of Wetland A for the construction of existing homes. Construction of the water and sanitary sewer lines across the property have affected sail conditions and vegetative cover within a portion of Wetland A,the south side of Wetland C and�e buffer along the south side of Wetland C. Additionally the site had been partially cleared in the past, reducing the forest canopy oov�er allowing the establishment of non nazive species incliding Himalayan btackberry and reed canarygrass. With buffer avaraging as being proposed for this project there witl be no loss in total wetland buffer area maintained within the project. T6ere will be a net increase in the total buffer azea which would be provided with a uniform SOft bu�Fer,of approximately 7,OOOsq.ft. Project No.20104 Page No. 10 Mr. Steve Bock hme 7,2006 With thc provision of a somewhat larger habitat a,rea being provided wihin the Wetland Tracts, there will be no significant reduction in the "sowce" buffer function. The preserved buffers can effectively provide roles in maintaining wildlife habitat, and in providing biological support by way of ma�nta�n�input of nutrie�s and organic matter urto�e sytem. This function within the developed projed can be maintained and enhanced with the impl�n�tation of buffer enhancemern plainings as proposed for the project. As the vegetative cover on d�e buffer grows and mafiues the eff�activeaess in providing a physical bazrier will be increa.ged. This function will be fi�rther enhanced by tbe instattatian of fencing to limit encroachment into the designated weti�a�d tracts. "Sink" functions to pratect the wetiand will be maintained in part by design of the storm water tr� systean. This system can cantrol tbe move�nent of stormwater urto and through the wetland to minimi�e impacts on wetiaad hydrology. This systecn will like�wise limit the movemeirt of untr�eated run off urto the wetlands. The proposed buffier averaging including enhanceme�plantings within the buffer can mair�tain a level of wetland and buffer function comparable to that which would be provided if a uniform S Oft buffer were provided within the r+esideatial develapment. New Water Line Constructiou A new water line is proposed to be constructed across the west side of the property. This water line is being � const�ucted to satisfy water service requir�nts for this property and �ther residential developme,nts in the area. Construdion of the water line will involve temporary disturbance to approximately 3,030sq.ft. of the bu�er for Wetland B. A vegetation restoration planting plan will be prepared when construdion design plans are finalize�for the project. �is P�S Plan will include details on the number, spacing and species'to be placed on t�disturbed soils within the water line easement area. All plant materials to be included in the P��S Plan will be native to the area, and to the extent possible species setected wiil be those native species presern on the property. Native trees and shrubs will be included. These plaIItings are intended to suppleme,nt naiural regeaeration and to accelerate the establishment of native shrub cover on the disturbed area. With the implementation of a restoration plan, tl� impacts from construction of the water line on the wetland buffer can be minimized to the exteat possible and the disturbed areas will be returned to a stable c�ndition, with native vegetative cover. A final restordtion plan will be prepared and submitted for review as final development plans aze Prepared. The restoration plan will be impiemented with the buffer enhancement ptantings. Buffer Mitigation/Enhance�ent Planting Plan We have prepared a conc.eptual buffer mitigation/enhancemerrt plan for ihe project. The general design iutent of this plan is to increase the density of native trces and shrubs within the preserved buffer and to cortroi the growth of non Project No. 20104 Page No. 11 Mr. Steve Beck June 7,2006 native invasive species including Himalayan blackberry, and reed canarygrass, amon8 others included on the DOE lisbing of invasive species. T'his conceptual plan is prepared to demonstrate the feasibility of constn�ction the project to mcet City of R�ntoa requirements for preserving wetland and bu�er fimction. A final plan will be prepared as final construction design plans are completed. 'Ihe wetlanid/buffer anhanc.e�nent plan involves four objectives: 1. Coutrol the growth of invasive plants, including Himalayan blackberry and Scat's broom (Cytisus I! scoparius)and others as included on the DOE listing of n�native invasive species. � 2. Increase the overall cover of native trees and shrubs. 3. Increase the native plant spacies diversity. 4. Restore the area affected by water line consauction. As finaE project design plans are prepared a final avtigation plan will be prepared. This plan will include detaits as required by the City of Renton. 0 Const�uction plan � Planting plan showing details of plant numbers, species and spacing ❑ Momtoring methodology. Monitoring will be carried out over a period of five years following completion of the work ❑ Standards of succ�ss for evaluating tl�e success of the projed in mcedng project goals and objectives ❑ Co�ingency plan We tcust the information presented is sufficient for your current nceds�,If you have any questions or require additi�ai infom�ation,please call. Sinoerety yours, A1 NVV � � Ga�et P. Munger Project Scientist Encl.: Table 1 Animal Species Observed or Expected On-Site Figure 1 Vicinity Map Figure 2 Site Map Figure 3 Buffer Enhanceanent/Mitigation Concept Wetland/Buffer Functions &Values Form Project No. 20104 Page No. 12 TABLE 1 ANIMAL SPECIES OBSERVED OR POSSIBLE ON-SITE Cherie Lane North Itentoa,WasWngton Common Name Sciendfic Name AMPHIBIANS Northw�estern Salaimander Ambystoma gracile X Long-tced Salacnander Ambystoma macrodactylum X Raugh-skintted Newt Taricha granulosa X Ensatina Ensatina eschscholhii X Western Toad Bufo boreas X Pacific Chorus Frog** Pseudacris regilla X REPTII.ES Narthern Alligator Lizard Elgaria coerulea X C�Crarter Snake ** Thamnophis s�rtalrs X w.Ter�trial cart�snake Thm,mvph�s eJegcy,s x Notthwestern Garter Snake Thamnophis ordinoides X BIRDS Shar�shinned Hawk Accipiter sMatus X Coope�s Hawk Accipiter cooperr X Red-tsiled Hawk ** Buteo jamaicensis X American Kestrel Falco sparverius X Rock Dove *� Columba livia X .. J�I TABLE 1 (CONTINUED) ANIMAL SPECIES OBSERVED OR EXPECTED ON-SITE Cherie Land Nort6 Rentao,Wsshington � Common Nxme Scientific Name BIItDS(Continne� Band-tailed Pigeon Columba fasciata Common Barn-owl Tyto alba Western Screech-owl Otr�s kenntcottii Crreat Homod Owl Bubo virgi�ianus Rufous Hummingbird ** Selasphorus rufus Dow�y Wood}�ecker*�' Picoides pubescens Notthern Flicker ** Colaptes auratus Pileated Woodpecker Dryocopus pileatus w�wo«i� conro��.�a�,r� Willow Flycatcher Empidonax traillii Hammond's Ftyc�tcher Empidoncr�c hamnrondif Pacific Slope Flycatcher Empidoncar diffrcilis Troe Swallow** Tachy�cineta bicolor Volet-green Swallow Tachycineta thalassina N.Rough-winged Swallow Stelgidopteryx serripennis ' Cliff Swallow Hirundo pyrrhonota Bam Swallow*; Hiru»do rustica Steller's Jay*• Cyanocitta stelleri American Crow'�• Corvus brachyrhynchos Black-cappod Cluckad+ee** Parus airicappilus Chest�►ut-backe�d Chickadce Parr�s rufescens Bushdt ** Psaltriparus minimus "� Red-breasted Nuthatch*' Sitta canadensis Bmwn Creeper ** Certhia americana Bewidc's Wren** T?rryomanes bewickii Winter Wren** Troglodytes troglodytes Golden-crowned Kinglet Regulus satrapa Ruby-ctowned Kinglet Regulus calendula Swunson's Thrush Catharss ustulatus Hermit Thnish Catharus gunatus American Robin** Turdus migratorius Varied Thrush Ixoreus naevius Cedar Waxwing ** Bomby�cilla cedrorum European Starling ** Sturnus vulgrrris Solitary Viroo �reo solitarius Hutton's V'u+ea Vreo huttoRr TABLE 1 (CONTINUED) A1vIMAL SPECIES OBSERVED OR EXPECTED ON-SITE C6erie Lane North Reaton,Washington �ommon Name Sc�entific N�me BIRDS(Continued) Wazbling V'ueo �reo gilvus � Red-eyed V'u� Vreo olivaceus Orange-crowned Warbler Yermivora celata Yeliow Wazl�ler Dendroica petechia Yeltow-rumped Warbler++ Dendrorca caoronata Bladc-throated Grary Watfiler Dendroica rrigrescens McGilliviay's Wazbler Oporornis tolneiei Common Yellowthraat Geothlypis trichas Wilson's Wafiler Wils+onia pusiJla Westem Tanager Piranga ludoviciarra Black-l�e�ed Grosbeak Pheucticus melariocephalus Rufous-sided Towhce** Pipilo erythrophthalmus Song Sparraw#* Melospiza melodia Whit�ro�vned Sparrow •� Zonotrichia leucophrys Dark-eyed Jut�co ** Junco hyemalis Red-winged Blackbird Agelaius phoenrceus Brown-headad Goa+bird Afolothrus ater Putple Finch Carpodacus purpureus House Finch ** Carpodacus�xexica�ras Pine Sisidn Carduelis pinas American Goldfinch Carduelis tristis � Evening Grusbeak Coccothraustes vespertirrus House Sparrow ** Passer domesticus MAD�IIIZAI.S Common Opossum Didelphis virginiama Trowbridge's Shrew Sorex d�owbridgei Vagrant Sht+ew Sorex vagrans Dusky Shrew Sorex obscurus � PaciSc Water Shrew Sorex bendirei Shre�vv-mole Neurotrichus gibbsi Townsend's Mole Scapanus townserrdi Pacific Mole Scapanus orarrus Littie Brown Myotis Myotis lacijugus yuma Myotis Myotis yumae»sis Long�ared Myotis Myotis evotis TABLE 1 (CONTINiTED) ANIMAL SPECIES OBSERVED OR EXPECTED ON-SITE Cherie Lane North Reaton,Washington Comman Name Scieutific Name MA1VtMAIS(Cootinued) Eastern Cottontail Sylvilagus�loridarrus Motmtain Beaver Apladontia rufa Tovvnstnd's Clupmunk Eutamias towrrsendi Eastem Gray Squirrel** Sciurus carolinensis Douglas'Squirrel Tamiasciurus douglasi DeEr Mouse Peromyscus maniculatus � Bushy-tailed Woodrat Neotoma cinerea Oregon Vole Microtus oregorri Hause Mouse Mus musculus Raccoon *# Procyorr lotor Short-tailed Weasel Mustela erminea Long-tailed Weasel Muste/a fre»ata Stripad Skunk Mephitis mephitis Coyote Canis latrans Nates: ** Species observed on property, including visual sightings,vocalizations,or ind.irect evidence such as tracks,burrows,nests, or scat. Wetland/Buffer Functi�� & Values Form Cherie Lane North Wetlands A and C Cowardin Class: Forested Local Rating: 2_, Wetland size: - Date: Occurcence Principal Function/Value Y N Rationale Function s Patential Im act from Buffer Avera ' Flood Flow Alteration Y Wetlands are on slape limited capacity Buffer averaging will not affect capacity for to retain aurface water. retention/detention in wetlanda. Sediment Removal Y Wetland does not have surface Minimum 25ft buffer along with stormwater connection with other waters. treatment system will limit sediment transport to wetlands. Nutrient& Toxicant Removal Y See sediment removal comments See sediment removal comments. Erosion Control & Shoreline N Stabilization Production of Organic Matter Y Wetland does not have connection with Opening up adjacent upland allows more sun and its E ort other waters and more bio rodu�tion in buffer&wetland General Habitat Suitability Y Wetland has relatively low species and Buffer averaging will not reduce habitat area structural diversi be ond that rovided with uniform SOft buffer. Habitat for Aquatic Y No flowing water soils remain saturated See comments far genera] habita,t suitability. InveRebrates to rovide habitat Habitat for Amphibians Y Limited ponded surface water for egg la ' > Habitat for Wetland-Associated N Area is small no open water or flowing Habitat area not reduced beyond that provided Mammals water for wetland associated mammal with uniform SOft buffer. habitat Habitat for Wetland-Associated N Birds General Fish Habitat N Native Plant Richness Y Buffer averaging will not reduce plant species richness. Total habitat area is not reduced. Educational or Scientific Va1ue Uniqueness and Heritage Wetlands are not unique in area Cherie Lane North �-�`' _. . - - `� .`L \` r F{-� `�s.��` � � � i ` 11'�/. � � I _ � l �.�" ` � �-� � ��, .-�, � `��_ i �: 1 � .- � r `f � O�� n� N � �S-30T_NtC1 \ _] � \..��1� ( �' � /_�tC',7� � -3'f' �%`- 7�(l�i �, i �,�qG I �` Y 1 i �_� ��Y�� ti ��I ��t \ '\ '� 1`� � � •;4 �,� �'..y/ � 1 � �/�tn i _i `\ � �1 � � ;`,; j /1, cf� i :•'----- � � � N N 5 31ST_ST __�: `S315T_CT � j �� f ( : - -_-- - ---�_ = � �1 t � �' % �' `1 N 1 � � �. i � � \ , 1ti ��a � ' ? S32ND:�! � `, ,.z.. f � � ';I � �I � ; _S_32N0_PL �� -- ; �� \ �i :� �_i �� _�ji � � , i � ,� Q :� i � '�il� .�� N - �� f N ------�` L.� �`/ ;+ i iu --_=---��''' } ___ --S_32ND:ST � J i: ��` � Q l � i'�`- ." , ~f � '! } • �,{ ; �� ,��1 ---� E f'_...'__._, � � � o � ��/ i �. , ,,y , i � ,_ S, • ! � � �� ', `--�`__� ; 1 l� i JI(` _ H- T� W_ ` --- ; ', t D_ i I �! z ` k�'� ` � �I � ' ! (� �`_._ � � ; -�` . ` � i I 0� � � � ; '., �_ : '� I.��5-35�ST�LQ� `, � , f :p -_ � \ . � �L_ N -_.,3.3dTH SL__ � --��`�/� ` �v ^ �. Ti ` � r , ' I � � 1 �'�' N � i D� -1 �'- _ � i1 ` C �i.f-- --- - --- ) j \ I � ��-.S_34.T.N�ST__.-r�` � I � �`�, '� �\��`` + � � � z �, �,� ,, . � i ---- -_ � � �i �� -_-�-��—� . ' `�---�--- __,�. & �- \ /.=- � / � ,i1� �FY%%- '�;:�;�• `�� ,� -,.. � � �\� � t O ,:!''� �y.�' ,�,f�-..- _S`.36jH Pl_—=._"-�"..�y , } �. + � ,:� \� � � --_ � � �y�� SE 1ZdTH-ST� I i, , '�•� � � �. S_3TTH�S7 �� '�� S- ;�j�------�_ - i S'37TH ST i � LJ—'! � �ir-_T� `.i ; /'i�! , IC3 200�1(In0 E__:=:_J � � i �:�— 0! �55111 I i � VICINITY MAP LD E RN W Cherie Lane North Renton, Washington roject No.20104 Date June, 2006 Figure 1 , z TRACT D yJETL TRAC 7 ,263 Sf i 13 �,ti . zc �� '� .i • �,`\ •�''�� '��.o � � '�j' c6��,c'' �c 4 E � S 'o ' � � .�. . � w�nnNo 'c � wE ro CAiEGORY 2 � 24.95T� Restore following water line �� • •a . construction 3,030sq.ft. ��1'�� w. ,o .c!°" c� .d �o �� :I° .ti �Y � ! •� a._ � � J��'L L E e� �.�1� < . Area of buffer increase 16,388sq.ft. �S- ,: s�axr ,- \ `�• 's t��• j � Area of buffer Reduction 9,257sq.ft. ' `�'s �.°� �c ° e 1 • •�� B, a D TEN . °�•2 � iR CT �,�I'�° ; . e✓ ' 1 ��. �r 4079 SF�' �.ti l\ a�1 *Y ' R�� ' ' \\ , � � � ` � 1, i , , i $ � � APPROXIMATE SCALE 60 ' 64 12Q feet � - - _� �� 4 5 6 7 8 9 10 � 1 5 . i ''�: �P�. .ti � .s I ��. c' ,e e c � . �' `��. s c- � cb. ', �' • • ,e 1 � c- � .� � � .,o � �d��e � 6 � � �� L1.1 � �-� . �,c_ 8 �-i � �• ,o . �� > 0 0`"• �-,:•.," Q .d � c �' �►' . �/� G'M16 �� • V/ 1� � • � ,i .;ri . d J • c�s •�,c- 7 ' � I,r� � �°� tY � . • ; C„'• •y ��1, �.. e m �� • �.s •`�� r 0 ,. e Q'i. ,e �� . 3 T npt _ ) S. `�-� ��.�o,� �o � �,o •,a � - .�:c,�-.` �,- �_ .�e � .i �vr cr ,d ,�- • • �� I`� . 'G 1' � . �.� �� • u .e v� 2� ,' � .. c'�+.o c" �� c+`" s�c-° �" .� � �� `y�1� 4 , s� S.' 1d `� l. 1 ��• t{� � � 1� 6 Y Gw�` ��,` y,•4 � � ,jp s G�• • �• G�' 0 � •��' AC T f �: �,� � ��•y +'�• i • q1 �0� �5� � � 1� tS �� •1 �1 'i � ►y • Z r ► � ,� S. �4TH . lread con truc ed) � + �` I 'hfTLAt� iRACT 'R" � i I 12,082 SF i � SITE MAP Cherie Lane North er Renton, Washington Proj. No. 20104 Date June., 2006 Figure 2 � PLANT LIST �vmbol Scientific Name Common Name Size Ce Thuja plicata Western Red Cedar 2' -3' He Tsuga heterophylla Western Hemlock 2'—3' osier Cornus stolon�fera Rsd-osier dogwood cuttings - �+ose Rosa gymnocarpa Wild rose 2ga1 Hn Corylus cornuta hazelnut 2ga1 Ap Pyrus fusca Crab apple 2 ga1 Additiot►al native species may be included in Snal planting ptan. Placrting densities will be adjusted in the final P�nB P�- 518 North 59+� Street,Seattle,Washir�gton 981Q3• Phone (206)783-1036 emai{aldemw@aol.com r � , i 16 , 6/ �b • o � G' • • �� k �i � �2� 2C G' \ � 6 2�P p6G� • �G' • , 6 f �6 � � r .�, ,�2 ,� 2 � '�� pF.G�• I�t;�. Z G� �y'l 2 (�� g 1 �/� ,LA � ' Q�,G��" � �G f N ✓� i N •C' � � 1� ,O O� � � C+� 1b `fi '_ ,. � �� Q jG' ,�p�G� . ' f,C' �2 � � 6 06 Z � 0 a �F' •�,' � �6 F•, .�� ' �p�� 9 �`'o -- • P`' �, '�G/ \ �A G �7 �8 � �' �0 •�� V�' �E'G/� �� c °O �� N � ��o �a `a �'� • G,N � -�, y+� �� i • �a �6 � � � ��2 •��' ' � 5�-_. �8 • OF-G� • � O ��'2a 1$ ��'� �'1 B Or'- �'� � �Q�-L � r _rl} ,� y�.i� �Gp o — c`� Q,'` �, y�ta' — 8� � .,� �' � a � G e��,� , �'1 �� • � � a �O 1'� G�� ^ . . •� a � �ys ��y1' � � � s. � � G �,o �, '� �' d " ,� a � 1� �� 1 E1lMp•A a � � �� . qo � � F �� A � • ��' � � C N � � � � +I,� > � ' �� P5 Z. O �"� 2° � �� PS� � Pc�� '1 P pS � . P Iread con trucN�ed) 6U�FER ENHANCEMENT CONCEPT Cherie Lane North � � Renton, Washington Proj. No. 20104 Date June, 2Q06 Fgure 3 Appendix 3 AlderNW — Wetland A Hydrology Letter March 1 , 2007 ,I { � � � � I I 1� 05043_Wetland Hydrology Report_070224.doc � A1derNW '�'tarch 1, 200 i Project No. 20104 Mr. Steve Beck 19129 SE 14�th Street Renton, Washington 98056 Subject: �'�'etland A Hydrology Cherie Lane II South 34th Street at Vl�'ells A�enue Renton, Washington Parcel #'s 2923059188 and 2923059040 Dear Mr. Beck: As requested, ��e have reviewed proposed site de��elopment plans for the Cherie Lane North residential development with respect to the hydrological support to V4'etland A. AlderN W completed the wetland evaluation for the property as presented in the report dated June 7, 2006. That report describes existing wetland conditions on the property. More recently Alder?v'W completed a W'etland Mitigation Plan dated December 12, 2006. Engineering plans including the stormwater treatment system for the project have been prepared by Schweikl and Associates. Schweikl and Associates has prepared a Vl�'etland Hydrology Recharge Report for the Plat of Cherie Lane II. That report provides an analysis of the pre and post development drainage basins and calculations of anticipated stormwater runoff for design of the stormwater treatment system. An element of the storm��ater treatment system provides for directing roof and footing drains from Lot 6 of Cherie Lane II into Wetland A. Vl%etland A is an isolated wetland of approximately 6,0?2sq.ft., located across the east end of the propem. Hydrologically, this wetland appears to be supported by near surface seepage into the area. As noted in the AlderNV1-' wetland evaluation report dated June 7, 2006 and in the Schweikl and Associates Wetland Hydrology and Recharge Report, surface and subsurface drainage patterns affecting Wetland A have been affected by the existing residential development upslope to the east of the Cherie Lane II development. In particular, Lots 6, 7, and 8 of the Steigman Short Plat likely reduced water movement into the wetland. Additionally, construction of I the stormwater and sanitary sewer pipelines running along the South 34`h Street right-of-way would have likely altered subsurface water movement out of the wetland. In its existing condition, the seasonal hydroperiod ��ithin the wetland follows a pattern of recharge during the late fall and early winter as rain fall increases, and then becoming dn� in the summer and early fall when there is little rainfall. During the winter months and into the early spring, soils are saturated to the surface and there is shallow surface water present within the wetland. At the time of observations in April, 2005, we noted surface flows moving through the wetland from the north end below Lots 5, 6, and 7 of the Steigman Short Plat, across the South 34"' 518 North 59th Street, Seattle, Washington 98103• Phone (206)783-1036 email aldernw@comcast.net Mr. Steve Beck March 1, 2007 Street right-of-��-ay and into the south (lo��er) end of the wetland where it appears to dissipate and infiltrate. Topographically, the wetland is sloping so there is only shallo�a� surface water within the wetland. Later in the spring as rainfall decreases, there is reduced seepage and surface water movement into the wetland and the near surface water table lowers so that surface soils become dry in August and into September and October, when fall rains begin. Construction of the Cherie Lane lI project can have additional potential impact to the wetland Hydrolog�, Grading and construction of the residence on proposed Lot 6 would change surface and subsurface drainage into the south end of Wetland A. As a measure to restore and maintain drainage into the wetland, the stormwater treatment system includes a drain system on Lot 6 which collects run off from the roof and footing drains and from some of the lawn area and directs it into Wetland A. Vl�ater will be discharged into the outer limits of the buffer through a dispersion trench to be installed off the northwest corner of thc lot. The dispersion tren�h ��ill pro�ide a metering effect during periods of heavy prolonged rainfall. With installation of the drainage s��ste�m as proposed tor Lot 6, there ��ill be recharee to 1�'etland A. Glean surface water runoff from the roof and footing drains which �vould otherwise be directed a��-ay from the ��etland will be routed into the wetland to maintain hydrological support to the lower section of W'etland A. As designed and based on run off calculations used by Schweikl and Associates in designing the stormwater treatment system for the project, discharge of roof and footing drains into V4'etland A should maintain hydrological support to VJetland A and with little if any change in the seasonal hydroperiod. We trust the information presented is sufficient for your current needs. If you have any questions or require additional information, please call. �� Sincerely yours, AlderNW Garet P. 'vlunger Project Scientist Project No. 20104 Page No. ?