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Home My WebLink About03186 - Technical Information Report f'� �.� 3'� r.,�� ; BAIMA & HOLMBERG INC. I� 9 � � � TECHNICAL INFORMATION REPORT for Emma's Plat January 28, 2004 ��s�� a / SxU PE h tiQ'��w oF waL�j � �� l fr t 11332 Cv� ��,��I.S"I'ER� ��' S`sl�l�'AL �G E�IRES 11/30/04 Baima & Holmberg, Inc. Job No. 1004-022 Prepared For Bill Hughes 15220 Cedar Grove Road Issaquah, WA 98027 .�J 3 /8� 100 FRONT STREET SOUTH • ISSAQUAH • WASHINGTON • 98027-3817 • (425) 392-0250 • (425)391-3055 _ _ _ _ � �� . � � � TABLE OF CONTENTS SECTION TITLE 1 PROJECT OVERVIEW 2 CONDITIONS AND REQUIl2EMENTS SUMMARY 3 OFFSITE ANALYSIS 4 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSLS AND DESIGN 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6 SPECIAL REPORTS AND STUDIES 7 OTHER PERMITS 8 ESC ANALYSIS AND DESIGN , 9 BOND QUANTITIES,FACILITY SUMMARIES,AND DECLARATION OF COVENANT 10 OPERATIONS AND MAINTENANCE MANUAL ` i SECTION 1 PROJECT OVERVIEW � � I '� � � i � . � � ,_ � i Project Overview This project involves the development of a 4.32-ac parcel into 10 single-family _ lots. The site is located between Lyons Avenue NE and Nile Avenue NE,just nd north of SE 2 Court, in the southeast quarter of the northeast quarter of Section 15, Township 23 North Ra.nge 5 East. The site is wooded and generally slopes '. down to the east towards a wetland area located on the east part of the property. Per the SCS soil maps, the site is underlain with Alderwood sandy loam/till soil. Stormwater Control Facility A combination Level 2 Flow Control and Basic Water Quality wetpond is being ' provided to control both the quantity and quality of the stormwater runoff. The pond was designed using the 1998 King County Surface Design Manual (KCSWDIV�. 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" 1 . �\ 2 ` - ti � I _ { 4921 '� ; I ` f I _ �,, � . , �� N o v � ; , \p��Q�o, _ -�� i }� : Sk .. � � �� C' `t; R___)�� `�` i c,, ' � �;, ��L2 � ♦ . � S OIL MAP King County Department of Development and.Environmental Services ' TECHNICAL INFORMATION REPORT (TIR) WORKSHEET �i Part 1 �P:ROJECT OWNER=AND: - :Part 2 :':PROJECT:LOCATION AND� > . . : PROJECT ENGINEER - - - DESCRIPTION. . - w 'Pro'ect Name Pro'ect O ner 1 �T�t k �lJ �S ��tr'e�-�rs ��/a r Address Location Township � 3 ' Phone Range�� - ...�.`.�..Section t s Project Engineer - � ��'''� "t � Company I.w► �- �K-s Address/Phone L —3 Z'O7.S , ' . _ , _. I 'Part3 ':TYPE;OF�'ERMIT :'� _ .. ,, _ �._ . . _ • � :: -APP.-I1CATtON „ -� 'Part-4�:OTHER�FtEUIEWSAND PERMtTS x Subdivison � DFN1! HPA Shoreline Management o Subdivision COE 404 Rockery Grading � � DOE Dam Safety Structural Vaults Commercial FEMA Fioodplain Other _ Other COE Wetlands - ' Part 5 ;�SITE COMMUNfTY�AND�DRAtNAGE BASIN = _ - Community ry ,� ^� ��N l. [�' . Drainage Basin C�n�� , 1��_ �/ V Part 6.`:SITE;GHARACTERISTICS: River Floodpfain Wettands X Stream SeepslSprings Critical Stream Reach High Groundwater Table ' Depressions/Swales Groundwater Recharge Lake � Other Steep Slopes ' -. - _ .. Part 7 :SOIL`S . , < _ - - , , Soil Type Slopes Erosion Potential Erosive Velcoties d�� j� P,i,o��'� Additional Sheets Attached �Pait 8:; DEV.ELOPMENTtIMlTATIONS REFERENCE LIMITATIOWSITE CONSTRAINT Ch. 4—Downstream Analvsis Addifional Sheets Attached _ . . ._ _ . . , - ..,.. , r .. . . _ Part 9„'ESC REQUIR_EMENTS, = �._-----,_ ; ..:_ ` � - ' �� MINIMUM�ESC REQUIREMENTS ' ' MINIMUM ESC REQUIREMENTS `' DURING CONSTRUCTION AFTER CONSTRUCTfON ✓Sedimentation Facilities `Stabilize Exposed Surface . �Stabilized Construction Entrance .. �/Remove and Restore Temporary ESC Facilities �Perimeter Runoff Contro! �� lean and Remove All Silt and Debris �learing and Graing Restrictions �nsure Operation of Permanent Facilities ✓Gover Practices �F(ag Limits of SAO and open space �onstruction Sequence � preservation areas Other Other � � =Part`f 0 :SURFACE 1NATER SYSTEM '� _ Method of Analysis ( Grass tined Tank Infiltration 1�� ,�5 ` Channel �� ` , Vauit Depression Pipe System Compensation/Mitigati �- Energy Dissapator Flow Dispersal on of Eliminated Site Open Channel Stora e Wetfand Waiver 9 � Dry Pond � � Stream Regional Wet Pond Detention Brief Description of System Operation � s G � C C-t�G� E� � j2r4t1u wJ N N � Gt�1'� Facility Related Site Limitations �(J/� L � 7"�' D� Reference Facility Limitation 1 � � . . �. - _ = - . �: _ _- : ., , . : _. , ,. . .. � � - �Part7_1 STRUCTURAL;ANALYSIS _ -: Part.�2 EA'SEMENTSITRACTS : , .` ,. :. �:_;, . _ _., - ,. :, . � . :-.,:, � _.. ,. _ �-. -:. , ,-:,. : - - _�:_:... Cast in Place Vault �6rainage Easement Retaining 11Vall . �cess Easement � r Rockery>4' High Native Growth Protec#ion Easement : Structural on Steep Slope Tract ' � Other Other � -Part-13 SIGNATURE OF;PROFESSIONAL�EN�GINEER __ _ _ 1 or a civil engineer under my supervision my supervision have visited the site. Actual site F conditions as observed were incorporated into this worksheet and the attachments. To the best of � my knowledge the information provided here is accurate. i Si ned/Date C F � � � ,.... . . . . . . SECTION 2 ' CONDITIONS AND REQI:fIIZMENTS SUMMARY � 1 SECTION 3 OFFSITE ANALYSIS � 1 x "xua.w�� _—� � , � � ,�� /—� 1`� '� l_ tzsas .J �t� / � \v/ ��\ � x \ � 1 � � \� f/ � �� / \ I` \ X� s � `�.� � � �� , 1 \ �;,. � �� !II� / �:zzs � �1 �� \�— �, -"fX� , �,�� " � .� ` \> > 1 � J �/ \ �\\ \�,,)' /� � �. \\\ `` `\ ��\\'''�� \� ' ' �` � , \` � �\',I � /� x1M77 � � I � � X12S / � �� ! \ � ��„ ��/`�� r�� — / �� \� � _ ` � .� � 1 1 \`�, ' � \ \ , \\ I I `\ I\ us.oe��`� �.:i' � I :s.0 \ � / 1 . % -'� ��` �� Xits.se � x u�.s� ` � I �� zsso � � \\ \� X,xs -1� X � ,� N� �r l `--�\ � :..� ,�. ..�� I 1 � �� x ixs.a� � ��bf► 2Z � � 1 I I l /� ��1 � �\`^ / �,�.� , G i � � �i i �� \ `� `` � �, � r t � i , � 'X ' �� I�I 1► �� --� � �------ X tux� � r N 4� �,�� —� ,/ � \ r�^� � � �� `� � 1 � \ �i��\ �\ � _\ � Xtn.ao �-----��\r� s�----_-X ----- --=7�=�=='=r�=��=_�� r �._----' ,_--- � i �. ,-, � �� i �..�� ' .\J�� , i .�, .`---_ i r � , � �__--- � .. • � r .� i � � � � ,�� ,� i � `�� - 1' i�� `�i � � J •� �_ _.--�,-- �'� � � � � � � � �_� •�____,_- �� i�� ^ ��/ � �� ; � �\ `�--� ��/� � � �� % ( —``�� --'�� i—�—��/ � j l 1 � � � Xm. �. /\ �—__�/// 1 j � \`// � X i � r a „� � � / ��_--�i� � � � i ,,,.,o " i / �J � \ �J � / x �\ � i� l �� 1 +� � � �� _�—�� / r—_.l ! �� i�z� �— �/^'\vY �- � �C xi�e.x Xnc.� ' � � � /�' �� 1 � ' � �i�� /� -, X �_. ; ,; ,,. .-�� NL�r�, . 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' - �'^�, v� .. . � - _.. •� �� p ta'v']r asc a�� " 1 nT � �� p � The Doundaries of the se�sittve areas dis- �e wetWnds and iandsJide hazard maps /or played on these maps are aDProximate. additional potential seTsmic hazard areas_ l � � � 1 Additional xnsftire a►eas that hare not Wetlands and Iandsllde areaz are susceptible been mapped maY be prezent on a devel• to fafture durin9 earthquakes. Other sefsmic MtLE � opment proposal site. Where ditterences hazard arws not snown on this map are occu� between what is Illustrated on thae shorefina underlain Dy lacustrine sediments; maps and the Site Cond(tions,the actual pre- these are susceptible lo tiquefaction. sence or absence on the stte ot the sensitive �tea - as deRned In the Senziilve Arw Ordinance-fs the legal control. 1 1/Z 0 1 M0.E � SEISMIC HAZARD AREAS � NORTH I , SOURCE: 1990 KING COUMY SEt�SIT7VE AREAS FO110 I �� .,.. 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[+� � �,+ A i�, x e�p�+�_-� �q 1�� Ra.�M ' ,��.�/»��! J J�' .% � �' �� Y'�iYN�:Y��^��'Ul:M ' (Jl R � ��' �t��fi��N�� S W`MM��M rMww ♦♦ � • �� s'�� `'��, �A�w�! N�,'`"� ��'w' 4,�a t��1�.w�Y 0 y�q'"� `'�`� � � �d�.�i��'� i r ° �� .w �«► r� � ....�► �� ; ""S" ' �. ,�� ,� N � KING COUNTY WATER AND LAND IZESOURCES DIYISION C J � � po DRAINAGE INVEST'IGATION REPORT � • /�� age 1: INYESTIGATION REQtJEST Type � PROBLIIvI: �(/ . . ,F,cErvED BY: Date: OK'd b . ��° F11.E No. —4 Z • ' . � . .---- � _ _.__._ . —(Da ) _L� . _ ._.. �Eve�__'� . Recerved from: , NAME: � PHONB o��c7�' 020 O� - A�nxEss: — City-_`,�� State Zip�� Location of problem, if different: r Reported Problem: cAI.L FII2sT ❑ (Would Ia'ke To Be Present) . � . � ' � L�� . /�� .,- C�1'�(�Q� � ' /' , �� < </ � � � , , . `�24�� : ��G�C�Q ��%��C�:Cl.�c..; �%� � � �� - " � ,��` �� n� ' . `� ' �� , ,�� - �� 4�G � � � v �O�J � Plat r.ame: � ' �� Lot No: BIock No: � Other agencies involved: No field investigation required � , initials i O� - —�-- 2� � - -- N - i I/a S . T R ParcelNo. �6'121�304�'C) Kroll � Th.Bros: New �OS J . �j Old � �s � Basin�C�' � Couna�District� Charge No. IZESPo1vsE: Citizen notified on � by: �i_ phone letter �in person M� s✓/wits Qvi.•%e/ o�.✓ j�a'�' �'�zT/99. a r��drR-v'f' �S .�-✓ ,s. G.•v SPo� - n� .�a..-. .s-r/ j.e��- �iovs, Lr�.��'�- :k.v...i srF+..,r r�.tr- �'o..�a �.�9.�y Tya— •.7 - %�?' .�a��. �o a�s.✓j .>.a.�-i...r ✓�,ws ,s-�'�"'G� /�'�d' . DISPOSITION: Turned to on / / by OR: No fucther action recommended because: Lead agency has been notified: - � __ Problem has beeu correcfed. � No problem has been identified Prior investigation addresses problem: SEe F�� Private problern-NDAP will not consider because: Water originates onsite and/or on neighboring parcel. Location is outside WLRD Servi Ar . � ?� Other(Specify): DATE CLOSED: � / � / �/ By.: G��''�'�'�'�� - . ��g Complaint 99-0625 Quinn - ]nvestigated by Chris Treichel 08/30/99 I Met with Mrs.Quinn on site Aug.27, 1999. Her lot is Lot 44 of Briaz Hills Div 4. The property is relatively flat but the house dces sit in the higher elevation. There is a CMLJ block wall on the west property line. The water drains away from the house in all directions. They have a street to the eazt and south,a single-family residence to th�"west,and Maplewood Park to the north. She stated ihat she was worried about an area in the Northwest corner of the property where the water seems to slowty infiltrate. She stated that she and her husband thought that the sprinkler system for the yard maybe leaking,they are in the process of replacing some of the sprinkler heads. When they were digging the sprinkler heads up, she stated that there was water in the ground. She also stated that they smelled a waste type of odor. The area seemed to be the low point from the pazk,house and neighbors. She stated that this was occurring prior to the CMU wall being installed. Maplewood Park � Wet area � Blockade at - end of road CMU Wall 7( ' 2-4'tall � !�1 . - . F � � .m.. �. � y � . Q,. Lot 44 Briar Hilis#2 �s . SE�1� �i. � p�+�.��. ax:+i;;:�..-.i •..,;....�•.:�.-t : - � - " . '� ;:`.=�� -�� KING COUNTY WATER AND LAND RFSOURCES DIVISION :��_. DRAINAGE INVESTIGATION REPORT - - . � � Page I: INVF.STIGATION RFQ(7EST T�C �.�� PROBLEM: L JlCE'�'� �N� . ,ZECErvE�gy ' �- �c—�L c Date: 3�</ 9 � OK'd by: F�E No. ��Q�� Received from: � � �� -. - . — _ --..-—�-- -=- ---�- ---- - -� --- � �aY) i.�� ---{Eve)- -�--• -- � N�: �-t L� �J �/�S Lc-"� Fxorr$ Z�- /�� ADnxEss: ��/Jz � ��f/� �� Sc City /Pc�i�r�/ State w�l�Zip��'�'1 Location of problem, if different: Reported Problem: CALL F�RST ❑ (Would I,�e To Be Pr�eut) li�L-�2 CL�vG�; �L L - O J � 2/y7// / � / J9�r�Z�--��. ( , j��j� �e.v� a��--T � �«� . 4,af'� o�� s/i ��w�vy. �O h-U �A R/d� y/j�2 t� � Lr �c�D/�� , . �1' Plat name:�iYla� �n(,�S N� 'Z Lot No: S( Block No: , Other agencies involved: � � No field investigation required �u�s �� 'O G�03iP,y�'EDt..�.CiOMP = R ,�- � �� - -- - �� W f� 23 � � S . T R Parcel Na��l '�S�C) Kroll �'�I Il� Th.Bros: New��3 � _ OId � �(P ' Basin�� Counc�District �� Charge No. RFspo,�ts�: Citizen notified on L7 by. p one � Ietter . in peison u�/��" l3 9.�5 � . _, - DISPOSTTION: . �Tumed to on / � / by OR: No further action recommended because: � Lead agency has been norified: d� s l�t-��--i S'�P�-zi�}-� pPS'. ' Probtem l�as bcen coaected. � No problem has bcen ideati5ed. Prior investi farion addresses problem: � . � � s�F�� Private problein-NDAP will not consider because: Water originates onsite and/or on neighboring parcel. ' Location is outside WLRD Servi � Other(Specify): � DATE CLOSED: .�/ �7/ �� By: 1 � ��9�s " c=c:r�;ti'y„��:�s:��;��x:�-�..-r.�...ti:.�,� -- - - • � `Q y 4 Y,. � - __"" _" 'S .. L+�t�-4 } yp\Y 1`SY S�+�{lG �"lhLs �v.l"1 . r j�� '� .. ., a ' .. ' -�.�'�� D90515 _��,.�� C OUNTY FILE NO. --' .-,L� KING � Department of Natural Resources N�°�ME ALLAN KIESLER Water and Land Resource Division ADDRESS 14102 148TN PL SE PHONE 425/226-1446 Tg pAGE 656J3 DRAINAGE INVESTIGATION REPORT KROLLPAGE 811w DATE 1/27/99 FIELD INVESTIGATION �INT.DMSION DMP irrrrt�.s- DETAILS OF INVESTTGAT'ION: I - e9-oiaa IV I • SITE VISIT ON 2/27/99. RECEIYED CALL FROM L. GETTLE THAT A RJD POND LOCATED �N THE PIAT OF BRIAR HILLS DIY. � WAS CURRENTLY 1N OYERFLOW. MET WITH MR_ KIESIER AND FAMILY ON SITE. • INVESTIGATION FOUND TFiAT UPON SITE VISIT THE POND WAS OCCURING A BREACH OF THE SPILLWAY ONTO 149TH PL SE. THE SPILLWAY IS DfRECTED TO OVERFLOW ONTO THE R/YV WITH FLOW BEING COYEYED VIA CURBSIDE DRAIN AGE TO THE SOUTH. THREE TYPE 1 CATCH BASINS LOCATED AT THE INTERSECTiOtI OF SE.139TH PL CONTAINED WATEA OYERFLOW THE TOP OF THE BASIN,AS WATER IN THE POND WAS AT A HIGHER ELEVATION THEN THE RIA1 OF THE BASIN GRADE. FLOW FROM THE TYPE 1 BASINS ARE CONYEY SOUTH ON 139 PL SE.,AND WEST ALONG SE 13 TH PL. A 35' RUN OF 30'CMP IS THE OUTLET PIPE FRON THE POND TO THE CONTROL MANHOLE. THE MANHOLE REFLECTED WATER EHTERING THE �0'PIPE AT APPROX. 10X CAPACITY (-THAN �-67. 1HE OYERFLOW TEE-SECTIN WAS NOT lN OVERFLOW. THIS INUICATED THAT A BLOCKAGE OCCURED AT THE PIPE INLET TO THE CSJCBI. TREE _, __ DEBAIS FROM OYERHANGING EVERGREENS WERE REMOYED FROM THE PIPE INLET INCREASING THE AI�AOUNT OF WATER RELEASE TO THE CSJCBt. EVENTUALL�IAIITH SOIiAE AAANVEL LABOR THE BLOCKAGE WAS REMOYED AND THE PONO WAS CAPABIE OF DECREASIHG AND THE OYERFLOW CEASED. • THE KIESLER LOT IS LOCATED ON THE S.W. SIDE OF THE VONO WITH A PRIYA7E GATE PROVIDING ACCESS TO THE TRACT. THE BERIR ELEVATION ON THE WEST SIDE OF THE POND DID NOT POSE A THREA7 TO THE KIESLER LOT. WATER WAS DESIGNED TO OYERFLOW ONTO THE R/W OF 149TH PL SE. MR.KIESLER AND FAUttLY WAS VERY PLEASED WITN 7HE EDUCATIONAL EXPERIENCE AND OPPORTUNITY TO DISCUSS THE FUNCTION OF THE POND. SKETCH: ' . � �� 1 � L '_' S. Ef - =� +L . � FAl�su.-• eaaawx n1LL5 D[V tt ADDRESS:14005 149�PL SE �vT og s�Rv�G'Ec Np �Ku�c Covrrr�r �otiusSRo� �sEc,c� '� �Depattmsnt ot Natural Resources TRACT � PARCELA � W:t�r and Land Resou►c�Dlvl�lon - .�•��•.► MAII�ii'ENANCE DIV.4 STR SW 14-23-5 BASW LCR KROLL 811R' LOCAL DRAINACE SERVICES UNIT COUNCIL DLST.12 TYPE POIYD RETROFITCED IN 1997 BY S7'EVE FOLEY IIVYENTORY DATE 1 2I-98 armi►Ls:� � SPECIAL USE PERMIT � NO MOW O " . MOW p �SPECIAL MOW � 149� PL SE _ SE 139�] - • CB#4 30"CMY - CB�2 � � LF 30" _ I.E 361.0 EX.a4 OF. . . _ 30" BOITOM OF POND ELEV 360.5 ' ACCESS ' , GATE ' • I.E 361.0 � CS/ 1 30 35 LF 30"Ck1P CB�t3 - � EMERGENCY C`H�iINLIlVK FENCE 4' _ �-; - . ':. � R� _ion � " - ?'r. I . - •?r: " ' ,!i Emergen�y ' I� '�nar,cz Dirision: 4 Thosas Brns Map: b57A3 �A t W13995 Facility t: D90515 " � I � Pc�d Briar Hills t4 Street Address: 14005 149th Pl SE � Directions: FROM SE 128TH ST, TAk;E 144TH AVE SE. . GD SOUTH. TURN LEFT ONTO SE 142ND ST. TURfJ LEFT ONTO 149TH PL SE. THE FOND IS ON THE LEFT AT HOUSE * i4005. - Che�ked on 2/27/99 br Pat Sieaonz Y J! . Radio t: 55i Charge to Project t: 4b7415 Fisheries: K S�ecial Equipment: � YLP.D liateslCan�Pnts:. - � . Thz 5locka�e ra5 re:oved during an eoergencr call out 02/21/49 and the pond receeded. The facility ras che�ked on 03104/94 and ° all parts r�re vorking coriectly: � jt..� ��j5, - � � �jr . /'s yU� -�� s! 1 Rosas Dir. Notes: (�' � Q� 5 . . � - d��- - . � � - -. U� s - �� . � . - . Ta it t � Date Actual lfaEerial Nateiial � '' 'e � ype Uaits ��rt Requested � Cc��leted Uaits Init Placed Ezc�rated � �Yob Lin.Ft. 1 �P.e:ove debris fro� trash racttsl it pipe endts): POMD - OUTIET. (ref394) . � I� � Work Authorized: Date: 3' `'9 Work Completed ' Date: � � Progra� Version: FeSruarY 21, 1993 � � . � � ' �_.. ' - . . ��.'.: • ,� • . � . " . - .. _ f,---- L��-xU� uv v�a i tt�x-TTL7"!V .t�:YURT �f�v .V� . �^- 1 Page I: INVESTIGATION REQUEST Type � PROBLEM: 1"O �"�- RECEIVED BY: M� Date: �� OK'd by:��Frt,E No. ��Q 7 Received from: _ (Day) ��- ) (Eve) �_ NAME: � "i {�. PHONE ZZ�G � ZZ�Ci AD�xEss:��' D� (�1�'' � � City�n�� State Zip q8Z�5, Location of problem,if different: � �� cJ � Reported Problem: CALL FIRST ❑ (Would L�ce To Be Present) 1�� 4uu.:f-{.c�-hri. -f-t2rr� �xac,vla brdKf, I�OS� � ��s �o-�- ��- P� . - � - �Gr-u c,�t. -� �i-bc �tx�t�� ►�r� �5 �-t'.xru�- 5-l� �#- �F v��=r Wd+c�r �s r��t ar�ot �e��'►��. Cc-'�e . �,�}� ' cr� � d.+�u.u'� • '� r►-;eoC_{c,��v�- -�tavd _ V� �- � •� � . � - ��-�� . 'lat name: �YIG�-� �t l�S 1J0 4 Lot No: �� Block No: Other agencies involved: No field investigation required ' - . .. . 'Y . (inidals) . _ ." TO BE COMPLETED BY COMPLAllVT PROGRAM STAFI?-;:=';=._;;:,,��',. r �.-?��t_••�-•.� �. .i .s. 5v�1 - 14 23 „� � - (�s� �-3 'S� %a S T R Pazcel No.ID�7�D3—D5� � Krolt�l�_ Th.Bros: Ne�'�`(.�-�.�0 S3 Old` 35�� Basin .�_ Council District �2 Char e No. g IRESPONSE: Citizen notified on /- S- y�' by: phone • letter 7r in person I I �Y` ��4`t� Q� (�f/2i rL ��' � � ��Y� G4J/�� / / ' �•-+C.J Q � "1"' � ♦ DISPOSITION: Turned to � on / / by OR: No further action recommended because: ._� Lead agency has been notified: �c1 �s %i�`�l� r�-z ls�L n�s Problem has been corrected. No problem has been identified. Prior investigation addresses problem: � See FttF� Private problem-NDAP will not consider because: , Water originates onsite and/or on neighboring parcel. Location is outside WLR.D Servi Ar . Other(Specify): DAT`E CLOSED: �/Z f / � B : � . Y � �1�� - - - ��.,+^! Page l: INVESTiGATION REQUEST--- —--- 'j'ype �� PROBLEM: �J�(.J� RECEIVED BY: y I�ii Date: I5 OK'd bv: Frt,E No. Received from: (Day) �7S?�) (Eve) �_ NAME: _ L�+�'viZ' SLI/�r''ltC��` PHONE ZZ�O � SZ.�3 ' ADDRESS:_ ��I 2� S�i 1-T � � � Cl ty �_ State Zip Location of problem, if dif�'erent: �(�CJ�CJ � , Reported Problem: CALL F1RST ❑ (Would Like To Bc Present} C,j�l,�U��' rY(�(�V1! 6-l� Gl,l'� �5 ��--t i'l!� ��'trl/�t!�(� Iit� U�L -�'�/��. �J (.J t�:�.dr,l�- o� -11�- �� - - -tlat name: Lot No: Block No: , Other agencies involved: No field investigation required ('u►ic;als) . . . . TO BE COMPLETED BY COMPLAINT PROGRAM STAF�:;;c`�,;;�;�-,: : ��:"_:=;-��; - . _ �I ' • . . � _ � - . � /a S T R Parcel No. Krolt Th.Bros: New � Old I � � Basin Council District Charge No. � RESPONSE: Citizen notified on by: phone • letter - in person DISPOSITION: Turned to � on ! / by OR: No further action recommended because: - Lead agency has been notified: Problem has been corrected. No problem has been identified. Prior investigation addresses problem: ' S�Fi�!l _ Private problem-NDAP will riot consider because: , Water originates onsite and/or on neighboring pazcel. Location is outside WLR.D Service Area. Other(Specify): DATE CLOSED: / / By: " ' — ��r�rvr-,.,c,-v,a�,«....,,.�.� sncruz-X: E�uwst 7i�us nTv rr-� I ; �� ADDRESS:14005 1�9"�PL SE DUr�F SERVICE: NO L�i��G!KING COUNiY �nionaws Bxos.: asEc.css.i3 �Department of NaWral Resouress 7�RACT PARCEL M W�tsr and Land Rssoures DNfsion - ��. htAWTENANCE DN.1 S77t SW 14-23-5 B�IN �.R KROLL 811W � LOC.AL DRAIIVAGE SERVICES UNIT COUNCIL DLST.12 TYPE POND RETROFTITED II�i 1497 BY S7'EVE FOLEY WYENTORY DATE 1-21-98 ��-�� SPECIAL USE PERMIT � NO MOW O � . MOW � SPECIAL MOW � 149T� PL SE SE 139� CB#4 - 30"ChiP . CB#2 , LF 30"C . I.E 361.0 AB N � EX.84 OF 30" BOITOM OF POND ELEY 360.5 - ACCE.SS GATE - I.E 361.� 1 30 35 LF 30"C11� CBtf3 EMERGENCY CIiAINLINK FENCE 4' , ' J 'm gency ra� � � Mai "ance Dirision: 4 Tho�as Bros Map: 657A3 YA t Wi3063 Facilitr t: D90515 TyPe: Pond BRIAR HILLS t 4 . Street Address: 14005 — 149TH PL SE . � � Directions: FRDM SE 128TH ST, TAY.E 144TH AVE SE. GO SOUTH. TURN LEF - SE 142ND ST. TURN LEFT ONTO 149TH PL SE. _ THE POt�lD IS OI�I. THE LEFT Al 14005. . � �� Checked on 1/15/9E by DOU6 DOBKIHS� Radio t: 555 Charge to Project t: Ob7415 Fishi '� Special Equip�ent: � ��r -� - 5MM NaEes/Couents: . � � Repair inlet pipe to CS/CB1 �nd backfill ►ith 4 to 6 inch spalls to an�hor pipe. If You have anr questions cancernin artchoring of the pipe please rontact Doug Dobkins at 29b-19I5 or on Cel! bb0-b352. J � . Roads Dir. Motes: . � . :� � � ��M - � Task Unit = Qate Actual ilateri�l Mater - Cude Type Uoits Yark Requested . Coopleted Ik►its IaiE Placed Excar� Y02 Ea.Fac. 1 �Re�ore 5ediient in control strncture CSCB/1. (reE14! � � Y15 Euh 2 �Re�ore sedi�ent fro� tAe folloring catth basia(5? and dispose in ucardirtce ritb appliable Regulations: CBt2 � CB=3 Iref210) �: j�° Y24 Ea.F�c. 1 �Perfor■ the folloring �ainteaance/rep�ir york: repair � inlet pipe ta CSlCB1. see notes iA the cw�ent zection.. � {refb601 � .-. � . . WorY, Authorized: Date: :-� � - i�% � Work Completed : Date: Pr�gra� Version: Febrnarr Z2, 1993 � � . �� y � � - - - ... � King County Water and Land Resources Division Drainage Investigation Report TYPE• FC; Page 1:Inyestigation Request � Problem: pond RECE[VED BY:MELANIE W. Date 1-5-9� OK'd by:DRH File Number• 98-0007 Received From: Name:OIQEGAETZKE Phone: Day 425-226-2276 Phone:Evening � Address: 1390y 149�;PL SE City: RENTON State: WA Zip: 98Q59 Location of Problem,if different:D90515 BRIER HILLS NO 2 CALL FIRST� (WOU[D LIKE TO BL TRESEKn . Reported Problem:PIPE OUTLETTING FROM DRAINAGE POND BROKE LOOSE AND IS NOT DRAINING TI�E POND. THERE IS ABOUT 5 TO 6 FEET OF WATER STANDING IN THE DRAIN. WATER IS RISING AND NEIGHBORS ARE WORRIED ABOUT FLOODING. ' PLAT NAME:BRIER HILLS NO 4 LOT NO:TR A BLOCK NO: pAST COMPLAINTS: OTI-�R AGENCIES INVOLVED: NO F1ELD INVESTIGATION REQUIRED rRws •'TO'BE CON�PI:ETSD�Y'COMPI:AIIa'I'•PROGR�M ST�iFF•. . . . . . . . '/. SW S 14 T 23 R S Par�cel Number: 107203-0540 Kroll 811 W Thomas Bros.:New 657 A3 35E � Old 656J3 35D6 Basin: LCR Camcil District 12 Charge Number: Response: Citizen notif2ed on 1-5-98 By: Phone Leiter In person X I VISITED Tf�SITE AROUND 9 AM AND TALKED TO TI�T�NO NEIGHBORS'THAT CALLED IN'THE COMPLAINT. I EXPLAINED WHAT THE PROCEDURE WAS TO FIX TI�PROBLEM AND A TIME FRAME FOR TI-�FIX. I TALKED TO STE` FOL�Y AND LARRY GETTLE TO GET SOME DIRECTION FOR TI-�WORK AUTHORIZATION. CUT THE WORK AUT�IORIZATION ON 1-21-98. FILE CLOSED WITH WA#13063 Disposition: Turned to On / / By - OR No further action recommended because: Lead agency has been notified: Problem has been corrected. No problem has been identified. Prior investigation addresscs problem: See file# Private Problem-NDAP will not consider because: � Water originates onsite and/or on neighboring parcel. Location is outside WLRD Service Area. Other(Specify): � DATE CLOSED: / ! BY: K1Ilg COUIlLy Name: OKIE GAETZKE Complaint#98-0007 Department of Natural Resources .� Received 1-5-98 Water and Land Resources Division Address: 13907 149 PL SE q�;�d Date 1-5-98 Local Drainage Services Unit City RENTON State WA Zip 98059 Report Date 1-I I-97 Phone: Day 425-226-2276 Thomas Bros.657A3 Basin LCR Council Dist. 12 Initials DCD Phone:Evening STR SW 14-23-5 Facility#D90515 Investigation Date 1-5-98 Parcel#107203-0540 Maintenance Div.4 Plat Name:BRIAR HILL.S tk This complaint was referred to me over the phone by Melanie Wasinger around 10 arn. I went directly to the site and found the pipe sticking in the air at a 45-degree angle. When I got out of the car the pipe pulled away from the joint and fell. Water was draining tluough the outlet pipe. Sediment and rock were flushed down stream and into the con�-ol structure. At the time l opened the - emergency shear gate%:way to make the orifice wouldn't plug. Once taIking to Steve Foley the t-section was an open-ended pipe I closed the slide gate. I called Larry Gettle to inform hiin what was going on and have him tallc to Steve Foley. Descriation of the pond and outlet pipa The pond was retrofitted a couple of months prior to this incident by Clean Services and Designed by Steve Foley,Senior Engineer, I LDSU. The pond slopes were denuded with no erosion control. The outlet pipe appeared to be loosely compacted and may have contributed to the problem. When walking around the pipe I sank 12". � The outlet pipe floated then separated from the first joint. Appmx.a 15 to 20 foot section. 'The trash rack appeazed to be cleared but I could not tell for sure. Talking to the neighbors they could not te11 me if the trash rack was plugged. The descriptions I received fron � the neighbors indicated the pipe floated and was not blocked at the trash rack. Complaini should be forwarded to Steve Foley and the Retrofit file. A sketch of the new retrofit needs to be done. ' _ ' � � DRAINAGE INVESTIGATION REPORT � �r?�� Page 1: IxvEsncnnoN REQuEsr Type ��J'' ` PROBLEM: . RECEIVED BY: Date: OK'd b : -'•�`{'� FILE NO. "1��-��"J3� Received from: // ��s � 7 � ��- �f j . (�aY) C��LL1 (B�e) �.� NAME: C�� /�/�lI� PHONE �c�l.� l�� ADnxEss: �'�c�o2 �/�9�,J �� City State Zip Q��i Location of problem, if different: �� /�� /,t,/O� �jJ�'� � / I -t" Reported Problem: CALL FIRST ❑ (Would Like To Be Present) c5'!!�f!? a? �. �Q,D � � . ��z�.i�� l�9�,0/��?� G/�°.� ��.G�.:�..�o...�.��!�-c-�-�- � z��'�Po C'i��, ��'��t !�/a2� ��,o � �� .�z.a�'` ��.��r �z� �r.o� �� vzt,�.� c� � �.o �"� c�2�P/� �� " , , � � � . . /�Gy��!/J �1�.l/IG��c',�I�.,�91/>2.f� . C%��r�0 �%�'l�'�� ./ r IO"" �(.Q� 1'� — .4� .at narne: �jr��ut �l�S �]7�tv6�,y) Lot No: �}— Block No: Other agencies invotved: No field investigation required ' (iniGals) • . � .'TO BE COMPI:ETED BY�COMPI.AINT PROGRAM STAF�?:':'"�;;ni.�:a_.�.:��'�';'.=-v:c`;;':;;- .S� . �4 2� 5 � - - - % S T R Parcel No.l D�1 ZDD— 04��J Kroll lR I V1/ Th.Bros: New � �'3 - � Old � 7�� Basi � Council District � Charge No. RESPONSE: Citizen notified on ,��3 �7 by: _ C� phone - letter in person C��(1.�� --�� -1�.�� -a /�-lr. W��I.E. %-c�I� ��-� �'�,.`,t-� -��. �/�T c�.,Y/ ��!/ C.aJ!'E�` (�t�(�c�r In��c'4 0�� yd �r� �� j/_ L � '��i.•'C.. �-d(�, �O �� / � ��ci�--� ��u� `�Y �.S�� '� DISPOSITtOIV: Tumed to on / / by OR: No further action recommended because: Lead agency has been notified: Problem has been corrected. No problem has been identified. Prior investigation addresses problem: SeE FI[.e# _ _ Private problem -NDAP will not consider because: Water originates onsite andlor on neighboring parcel. Location is outside WLRD Serv� ea. Other(Specify): DATE CLOSED: � I��, � .�� By: ,' ' , _ n ., , �� i� .;" � =_ _ ,.��'-_ � I — - � i . King County water Ann Lana ne��-�.-�i„,=�� I Drainage Investigation Report �E�.:.c! Page l: Investigation Request blem:FLOODING JI .�ZECEIVEDBY:CI'M Date: 11-1�-9� Ok'dby: DRH FileNumber: 97-1537 Received From: If Narne: ALTON WF�TE Phone: Dap 425-235-9119 Phone: Evenin� � IAddress: 14202149� PL SE City: RENTON State: WA Zip: 98059 Location of Problem,if differenk: SE 142ND& 149�PL SE ! CALL FIRST� cwocna cs��ro ae rxssExn � I Reported Problem:SWM OR SOMEONE HAS A DRAINAGE PROJECT BEHIND HIS HOUSE. HE � THINKS CREWS COMPLETED JOB YESTERDAY. WORK WAS EVIDENTLY NOT FINISHED OR � DOES NOT WORK BECAUSE WATER IN NEIGHBORHOOD IS NOW OYER THE SIDEWALK AND ( RISING. POND IS OVERFLOWING MUDDY WATER INTO THE CREEK WHICH DISCHARGES INTC THE CEDAR RIVER. . � I - � � I � '1362 . . ' � . J498 � 1i . i PLAT NAME:_BRIAR HII.LS fD90G69) LOT NO: 44 BLOCK NO: . PAST COMPLAINTS: j + I O'Tf�R AGENCIES INVOLVED:I�N K:RANKS GROUP ' NO FIF,I.D INVF.STIGATION REQUIRED .�ws � :��:..• .:•, -x.- .,; .X. ,.� .x. . ,,. _'.��.��:.' x II . � �/. SW S 14 T 23� R 5 Pazcel Number: 10720U-0460 Kroll 811W T6omas Bros: New 1 I . . Old Basin: LCR . Council District 12 , Charge Nomber: iIRespo►uc: �tizen notified oa_12-16-97 By:_x_Phone_I,etter�n person ! I called Mr.White to confirm what his concerns were with the complain� Mr.White is concerned with what the project was on the po�d behind his home. I told Mr.White that I would forward this complaint to Steve Foley since he was the lead enginccc on the retrofit of the I ( ponds. Forwarded a copy of complaint to Steve Fo[ey concerning the problem in ihe area an a note to call the complainant dd l.7`�3` y 7 G Ct�l-.� M�'' �J�t/"�C. �J'e�c �/,r/��w ��'�v�^ Gbl.�tt� Disposifion: Twned to On_J / By OR No furthu action recommended because: ( ( Lead agency has been notified: � Problem has been corrected. No problem has been identified. Prior investigation addresses problem: � See fde� I I Private Problem-NDAP will not consider because: � Water originates onsite and/or on neighboring parcel. Location is outside WLRD Service Area. Other(Specify): ± I DA'�E CLOSED: / / BY: F,: ..#-r.5 - ..r .. . ._ ., . +.. Y.,r�°��'�'' � - , -. ...._..� � � ''*' � y^ sy. -�,..�� COtvfPLAINT 96-0362 KOVACICH, MII�E Im�cstigated by Doug Dobkins on 2-14-95 � I met with Mrs.Kovacich at her home to discuss the concerns about the drainage problem they have • during big storms. On 2-8-96 the Kovacich property was flooded because of the water backing up in the intersection of SE 142nd ST.and 149th Pl. SE. The Kwacich's live on lot 43 of Briar Hills. Tract B of . Briar Hills is a County Maintained R/D facility D90669. The Kavacich's are the Iowest lot in the area so the water badcs up to their frontyard then drains to the east on the north and south side of their home. Mrs Kwacich gave me some pbotos of her property during the storm on 2-8-96. The water eroded the side yards and water seeped into the living room. This has happened before during the 1990 stoim. After loolang through the plans and profiles the Kovacich's lot is probablp built on fill because the topo shows ihe ravine behind their home going out to the street on 149th place SB. This wonId explain why the water runs through the Kovacich praperty once the water is high enough in ihe street I will screen this complaint with a Senior Engineer and call the Kovacich's back Left Message with the Kovicich on 3-9- 96. � � SE 142ND ST BRIAR HII.LS DN 1 Bx��-s nrv 2 � 149Tfi YL SE 1 '---�—► —>� �covwa� �rni � � � D90669 � �- - r TRACT A OPEN SPACE PLAT OF BRIAR HII,LS ' � ' _. . - . • - __..,�..e - . KING COUMY SURFACE WATER MANAGEMEM" DNiStON � - DRA�IAGE I]NVESTIGATION REPORT - �� Page 1: 1NYESTiGATtON'REQUEST Type - ived by. �,��i Date: 2-�-cj 7 OfCd bY• �ti`'�' F�1e•t�to.C��_�Gj 8 - Recsived from: � (Pfease pdnt plainfy tor ccanninp). . (Day} (Eve) NAME: .� �- �'�T�I � . PHONE 2 3`� "c1 I l `�1 � ADDRESS:� r� ��.- _�� L,I.�T �.� . . . .. . .._ C� -. -- . � State �� 2p� �Lc t.ocation of probiem. Ef different: . � � � � � . . � Reported P�oblem: � � �. . • . ' , . . - -- - ��OZ�/�� G� :'�`l' l..E.-Q.;�.�_f~ _ i.i- �L �-:t'.c`c�• i;- �t;_�:-E_i-. ��"�� •v��L.-�:u_r'Y�.- .�..Irl.t,�- . � ` v �y� �. Li..�r `- ,/�-`� � G��`:��r. i�.��. �.�-is C :C�_ %!-� - 4C��Gc'_ (,C`r. L�i_/ �c"d •d i t..i. �.?�'�_.: �t d c. �- : �;�E c!.��-�.s�t tl-� �� ti:f -�� u-":�K- �-t�1i.��-r ��Ic��S C� t�c� �-�;4-�"V�:r� '�-�t"i._�ri' `�i t ve.. /<�'�'✓�.��,; � �z c 7t.'(. ��ti�� O��4-;{ .l L;L��.c. .�%� .�-f rr t f-� �'' ,�•� � j-b;•�_Z Gt,,�_Flr_ . . � - � � .. _ . , . - • Plat�name: ��l f�1e �1-�`lu_J Lot No: ��- Block No: Other agencies invotved: . � , _ No Field lrrvestigation t�Ieeded . . • ,- �5� a��=��f-�� ':-��x�. r� ��3- �' =.• ,� ." .:. . ' ,: -�:��«-��,��_�ae�:#*��.��< _ . . : � - - • -- ...- --- - . . . . . : . . . : . _ . _ . . . . .. .: .�. � �- '• -----� - ._ ..X�h-`�.-.."a1m'��i.:< . fa&7�.2uL�c_A.. .. ._?i...,.A.., ...,..,-•----:.._s.�c_..r......-.:•-r---o.....� .<.:_.:__..:-•^-:.r ��A-. ::`aw�5xiih`^3?��:�. t '` .. . .,,, . �'�l �'�}-"" � U5 Parcet No. �C`77-f..TU�-c��v. Kroll 8�1 �ti' ThBros: New �'�i% T� . 1/4 S T � R . . - ' ' • 01d ��j5' T�(�„ . Bas(� L(,� � Coucic�l.Dist ��' C�arge No: • - , RESPONSE• Cit¢en notified on.3�Z7��l� by p one_ letter _in person . . � W j�--. J� P J P �' �f�i�s - ' . OlSPOSITlON: Turned to `On - by OR: No further actton recommended becau: Lead agency has been notified: � � � " _Problem has been corrected. _No.probiem has been ident�ed. Prior in4estigation addresses probtert . .. . �See F(e# . . ��ate problem-NDAP wil!noi consider because: � " Water originates onsite and/a on neighboring parcel � • _Locatior� Is outside SVYM Service Area. - . . _ . _Othe� (Specify): � - � � . ::`-'' DATE C�OSED:�� by; liy� G✓��" !ti I Z 3 I S _ � � ' ' r��r_::::vLs�:ll:.>t:�1�'`a:v?i.��:'.'�:_�-+.n.�i�!'a.s:wc:a+a.-�-i�K%%�.:.h:=.r....�::c..-..,tSKi:z•.::.s':;e:;._.�.v ti9ec:::S.r.�At?r?��-.�•nss4".t+E•��...=..5-''".-iTl�=�i�j?�'C�4-C��L`'S � . � � _ ��l AE� Nct�.S�'- 1 f � . ,� . �5fxo sE. (4�� st. � 9 � 35�-�o M� 4 I O � ; z��5��1 RMT ! -�.--- =-----. gE i�z�n sr. � . . .� � � .. � �� '-� . . :� �; , . � rs r�,,�� . .�"--- 'vo � ��D •.„ -f'�6.`,S '`��'`1�i�G � � � . ` � —' -�C � � �tr�tz�c�c- /� , ' � b�:.: - `�'� TQAGT � �� °-` �,, .�`�� `�: � � ,�� COc�Ni..�,, l . . c-c.�,�rc�o S,�uG�v� C kcE�v� . . � U � c� �, � . s �.- ,� o . � � , � N `�. . . � � � 1 . \ � . � � �-..._r...,..._ .... ......_.-_.._. :� � -, ' • �. � ��. $� � i �� .:`/ � � ��,, . ! ' ��,,� , ` , ' • ...� ��'..J _ � � Klh'G COUNTY SURFACc 1�rAT�� ti1�,NAC�M�N i DIVISIO� t� � . -_ -DRAI��.GE II�IVEST�GA.TION REPOZZ�' ` � T� � - . � - Page 1: (NVcS71CATION R�QU�ST Type � � - . . . . neceived by: L_ �-L �� Date.. , �' �Z 9G OK'd by: File n'o�(�/_ �/C _--------____ --�-:-��--�---_�______1�____-.--_--�-� ---.___-----_-----: <<� �--�� Received/rom: � . ' (Please print piainly tor scanninfl). . (Oayy - (tve) -Nr,N�: /;�rk�` /l o1�ffG/G {� � _•RHOi�lc �r1 "�Zl�' �� ' . ' ADDn�SS: �� - I�ff� �� .Sc,� • City.� C- - � - � State� �i�ia ` �_._Location of problem, �di�erent:- - ' ..- �- --• - . ...�-- • - ' �- - -� � � , � . . . . . " - ---- - .Rspo�:ed P�ob/em: " ' � • ' ' ��• � � �'�c�Fi2/�'�JCG'� /_ LO d fl//lJ l, ' �� /� dtJS� �OiQc� . � ��R . ,9�✓0 �h��..�.��s. - S.�r.-t� `(��o�z� ..Q-�S. Jf�,- � h�o�crv�-� S'c� � � i3� - ,�y��2 �^i� �i�� l�i�-�� /�'��.- ��s:_.. �O - . � � A - • • ' � ,pc-- �C �c •�,�....� �,�—Y :�� .pjP�/�✓,�1�� /�r/. /Y'2�7� �� . . . � . . - � � : . _ . . . - . . - . . - � - . � - �qb�� - . .- - � � � � � � . . =;_� ..�..._. ��- �-�i`l�s � � � - . � : ��: ��: .�3 �$��::�o: .C:i�c.'��:ili.i=S•...��i'!^-�: •' � � � . i�0 r{2iG� Ii�t'=SiiG:i� '1 n�=� � ' . ��• .�.J�.�i � � • . :_.1.'tiS; tYtZf�'lf�}iC�F�fT iC]ritf�w?-]c��CYw X�^:li�j:�� 1�/Yl��('J�7u� Y 14/�%�T�:�/.�^•••�'��• »'I^FIC��T�ii <ir X�C<s o•` ,� -��"� -r..-2 v'a ,/F�y,f��,�._.' i,�=�.'v..�•.•..�=1`�.J_:':Lv..�c...��:ti:�T'-5..: :�'>�:�.�.7.1�-�:�A_':2.:.5�.'.e.:r.:�:•�.+'rA►wl�i�:-.M?r:-::.r .'�..�/`...:'��:::_.�"�,r�Ea..._,..�`�S..a��sa.v«�� `3S ..........«....�....;�.a:c:.ww::.:.a..aacx�a�c.c:sacwcz:.r.w�.:.,cka.a�..:.�..,�c:�.:��..x.a�n�-.«,,;,wa..µ.�.x,.»'w.�<...wc.L`r'.33.�:�-_.:�...»-`�`-�:�.��:..�.. sw -J y Z3 .� . �:a��=t �.fl. � .�07200 0��3o ru�� '��w � �,,.��Q�� r.;.::C� :;; s ; - . : . - - - . ' . 35t�- , �'� �57. � :,�5:� �-Cr�-- co:�,�a o�s� 1 Z- c,�:�� no:. �� . - r�SPOh�S�:��C::iz�n noiri�� on :��- b� � p;��ne_ I:�t?r _u� perso� . - . ��1�� G•� Ic�Ct c.t r+,.��L w�-�►� t:.»c,�c..:�.3. Zn c��,..:t, o�'Sc.c�� w:-�t...._ : M+r' �o v..:c-:c.l-, -��'s �rocrc� ��or-�_ Se�-,-}- �-�5-lo c.�.-�- c.�.rr1t. - -��. - � Sce K�✓A.t�t�� . S�w� . R!D �r�-�o i-��'� S �3�� ► �� . S� (e�9"'l - DlSPOSlTlDlti'.• i urned lo _�� on 7 �� by O?: T�'o ��:�her ectio� re�o�::��d� �� !ezd zC�ncy hzs be�� rio.�i��:� : • _ :;ob1=m hzs b�zn coc;ect��, _ T�'o �ro�lem ��s ��n iosr;i�;�d. rrior in`ves�i�a�i�� a��ss=s • . Se- :Ae � _?rr��:e problen - n'�,'�.a v.-ill noi cons:d�r bec2✓s�: - ��1'cizf C:IOlflztes o�si;e 2i1:�/or o� n��c�bo:1:17 ac:C?� • � • ' � � `- ^ ^^-_ Loc�tion is o:l.s��e SV►�!•.�i S=rvice r.��a. - . _ O�h�r (Specij•): � ' _ �< , �� ,..- �� . .� ( COMPLAINT 96-0362 KOVACICH, MII� � � >, Investigated by I�oug Dobkins on 2-14-9� � I met with Mrs.Kovacich at her home to disc�ss the concerns about the drainage problem they have during big storms. On 2-8-96 the Kovacich property was flooded becaase of the water backing up in the intersection of SE 142nd ST.and 149th Pl.SE. The Kovacich's live on lot 43 of Briar HilIs. Trad B of Briar Hills is a County Maintained R/D facility D90669. The Kovxich's arc the lowest loi in the arra so tbe water backs up to Weir frontyard then drains to the east ou the north and south side of their home. Mrs Kovacich gave me some photos of her properiy during the storm on 2-8-96. The water eroded the side yards and water seeped into the living room. This has happened before dnring the 1990 storm. After looking t}uough the plans and profiles the Kovacich's lot is probably built on fill because the topo shows the ravine behind their home going out to the street on 149th place SE. This would explain why the water nms through the Kovacich properiy once the water is high enough in the stree� I will scrcen this complaint with a Senior Engineer and call the Kovacich's back. I.eft Message with the Kovicich on 3-9- 96. . sE iszrrnsr � 14977[ PL SE �—� *v�+ / �E_— �Kov�aot , - � xm� � � e / / s D90669 r - � � . TRACT A OPEN SPACE PLAT OF BRIAR HILIS � �� . . �� - �o�lz� � �C c(t� ; � Q,Q•q(� - �:`-�.�s �o�.�. o K a�5 � �c�.�,,,a _ �� SECTION 7 ' (NTRODUCTION AND PURPOSE � � � INTRODUCTION � The Kovacich drainage problem is located within the Orting Hill Subbasin of the Cedar River Basin in the Briaz Hills subdivision of Renton, near the intersection � - of SE 142nd Street and 149th Place SE_ T'he location of the problem area is illustrated on Figure 1. The problem primarily consists of flooding of the roadway and private property, especially along the natural flow path of the � Orting Hill.Ravine. The major trunk of the drainage system in question flows south along SE 149th Place,proceeds east along SE 142nd Street, and then heads � south along the west side of the Briar Hills No. 1 detention pond to the outfall at the top of the Orting Hill Ravine. The trunk system is primarily composed of 30-and 36-inch diameter rnrrugated metal pipe. The system's approximate _drainage catchment is 280 acres. . PU RPOSE � R. W. Beck was retained by King County Surface Water Management Division (SW1Vn to conduct a drainage investigation of this problem. The purpose of this study was to: � ■ Assess the problem � ■ Identify the probable cause of the problem ■ Evaluate and recommend solutions to the problem ` � . AUTHORIZATION � ' Preparation of this study was authorized by an engineering agreement with R.W.Beck,Inc. dated August 1, 1996, and the work order for this study was approved on October 1,1996. . � ACKNOWLEDGMENTS � King County Project Manager and representative was Steve Foley,P.E. Input was also received from other King County staf£ The prqject team from R.W.Beck included Jack Bjork, P.E., as Project Manager and Dan Mattson as Pmject Engineer. X1654121.943 1?�3I/'96 ' SECTION 2 . BACKGROUND/HISTORY COMPLAINTS/CLAlMS/HISTORICAL OBSERVATIONS This flooding problem has been investigated previously by King County as a result of complaints by residents. Actions to date by the County related to this problem have consisted of maintenance of the drainage system. In addition, the county completed some stabilization work on the Orting Hill Ravine which is � unrelated to the flooding problem of this project. The drainage system overflows and floods the intersection of SE 142nd Street and 149th Place SE, continues to . flood south along 149th Place SE until it eventually spills over the Kovacich's • � driveway into their yard and then flows around their house and through their � back yard into the Orting Hill Ravine (Please see Figure 2 which shows the approximate area of IIoodin�. 1VIx Mike Kovacich and other local residents said that the flooding in the intersection during the February 1R96 storm event was just below their waist � when they had waded through it. The Kovacich's submitted written complaints of flooding to the county in both 1990 and 1996. Based upon a plot by a county ernployee for the gage 31U recorded precipitation (2.84") the February 1996 was approximately a 9-yeaz storm event (plot is included in Appendix A). Based . upon the flow frequency analysis by KCRTS (please refer to Appendix A) the -January 1990 storm event is also approximately a 9-year storm event During R. W.Becl�s field investigation/survey some of the Kovacich's neighbors, who had not made official complaints with the rnunty, said that they had significant damage to their landscaping, but they had not had any water enter their house. T'hey also noted�that during both the 1990 and the February 1996 flooding, 149th Place SE became impassable for vehicular traffic. Based upon the King County report by Doug Dobkins and R.W.BecKs conversation with Niz and Mrs.Kovacich, the Kovacich property was flooded on � February 8,1996 because of inadequate conveyance capacity of the pipe system. The Kovacich's lot is the lowest lot in the azea so the water ponding in the street continues to increase until it reaches their front yard where it then drains to the east around their home (Please refer to the photos on Photo Fgure B). Apparenfly,the Kovacich's house is built on fill placed in an upper portion of the ravine. The remaining unfilled ravine is still present behind their house. Nix and Mrs. Kovacich bought the house in 1986. Since that time they have noted four storm events that have caused significant flooding in the intersection. Two of the storm events did not cause flooding that completely covered the intersecdon. On February 8, 1996, howeve� the storm event caused flooding of the intersection that ponded into the Kovacich's yard where the water eroded their side yards XI659121.943 ]?�3l/96 ' � SECTION 2 and seeped into their living room. According to Mrs. Kovacich, the 1990 storm created similar conditions including water in the living room. Mike Kovacich noted that during these larger storm events the flooding was approximately 2 to 3 inches below the top of his backyard deck (elevation 359.�. Mz Kovacich also noted that during these events the Briar Hills No. 1 detention pond filled more than one-third (Please refer to Photo Figure A). He also said the water Ievel in the pond was approximately 6 feet below that of the flooding in the street. Based upon conversations with his neighbor who lives next to the Briar Hills No. 4 , detendon, Iviz Kovacich said that pond aIways remained empty. The ravine behind the Kovacich property (Orting Hill Ravine) is the upstream end of the ravine which washed out down at Jones Road and 149th Ave SE. Mike Kovacich reported that the inlet structure had become plugged and the Jones Road pavement and much of the rip rap surrounding the new inlet structure was washed away during the February 1996 storm event. Howeve� , any further investigation into the erosion within this ravine is beyond the scope of work for this project. BASIN DESCRIPTION GENERAL I The basin tributary to the flooding problem covers approximately 280 acres. This basin will be referred to as the study basin. The study basin was delineated and called the J2 subbasin of the Orting Hill Subbasin in the Cedar River Draff Basin and Nonpoint Poilution Acfion Plan. The study basin Q2 basin) boundary is illustrated on Figure 3. The work done in delineating the basin in the Cedar River . Draft Basin and Nonpoint PoIlufion Action Plan was assumed to be correct and we did not field verify its boundary. Figure 4 illustrates the existing drainage system in the problern azea. The existing drainage system was based on field observations,survey,and available design drawings. DRAINAGE SYSTEM There is one primary conveyance system contributing surface runoff to the problem azea. The system is composed of 30- and 36-inch-diameter helical corrugated metal pipe (HCMP) that collects runoff from the Maple Ridge subdivision, the Briar Hills No. 1, 2, and 4 subdivisions, a portions of the Briarwood Lane and Lamans Place subdivisions and some undeveloped area. This system is shown in Figure 4. A profile is shown in Figure 5A and 5B. There are two backup type deteniion ponds that are connected to the trunk system. One pond is located directly behind the Kovacich's property and in this report will be refened to as Briar Hills No. l Detention Pond. Briaz Hills No. l Detention Pond has an approximate capacity of 0.75 acre-feet. The Briar Hills No. 1 Detention Pond was designed by developing a hydrograph for the deveIoped X1659121.943 lv3uv6 R. W.Beck �2 ' BACKGROUND/HISTORY , conditions and calculating the area above the existing peak discharge rate (please see Appendix A for a copy of these calculations). The second pond is located at the north end of the trunk system and in this report will be referred to as Briar Hills No.4 Detention Pond. Briar Hills No.4 Detention Pond has an approximate capacity of 0.2 acre-ft The method used in designing this pond was not available. Based upon local residents and the eounty's reports and pictures, these ponds are not presentiy functioning properly. The Briar Hills No. l Detention Pond �only fills to about one-third its total elevation which is approximately 0.1 acre-feet in volume. The Briar Hills No. 4 Detention Ponds currentIy appears not to be filling at all. LAND USE . . Land use in the basin is residential with densities up to four dwelling units per gross acre. SOI LS - Soils in the basin are mapped as AgC (Alderwood gravely, sandy loam, six to 15 percent slopes)which is in hydrologic group C. ENVIRONMENTALIY SENSITIVE AREAS The Kovacich drainage system dischazges to the Orting Hill Ravine. King County's Sensitive Areas Map Folio designates this water course as an unclassified stream. The ravine is rnnsidered an erosion and landslide hazard area. There are no mapped wedands within the J2 drainage basin but the King County Sensitive Areas Map Folio shows Wetland Number 150 immediateiy � northwest of the basin No wedand investigations were included in the seope of this study. xi�s9iai.� ��u� R. W. Beck �3 ' � � SECTION 4 - FINDINGS Figure 5A & 5B and Table 3 summarize the results of the hydrologic and hydraulic modeling.The hydrologic results from the KCRTS 15 minute/historicaI data were selected as the best estimate of flows because its results were the closest to that of the HSPF model and best matched the reports of the locai residents. Table 3 demonstrates the capacity at each of the structures. Please also see the plot of the hydraulic grade line for 28 cfs on�gure 5A&5B. Based upon the results of the model, the flooding of the existing system begins in the intersection where it flows out of CB 7 first. Catch Basins further upstream are surcharged at slighfly higher flows. The results of the hydraulic analysis indicate that the current, free-flowing capacity of the existing drainage system is exceeded by a �year even� It should be noted that the system overflows at the original 25-year design flow capacity. The streets will be significanfly flooded during the 5-yeaz event, and private property and the Kovacich residence wiIl be. flooded extensively by storms greater than a 5-year event, Please refer to the photos on Photo Fgure B. It is difficulE to determine the exact amount of flooding in the intersection and along 149th Place SE, because the water flows around the Kovacich's residence into the Orting Hill Ravine. The total voIume of reported flooding approximates 0.7 acre-feet. , , ; X1659121.943 1?l31/96 1 SECTION 5 � _ SOLUTI4N EVALUATIONIRECOMMENDATIONS The following are recommendations which will reduce and help to contain the peak flows in the drainage system. Each recommendation could be completed separately and be effective; however,in order to be most effeciive and to provide � the desired Ievel of protection all the recommendations should be completed. Because some of the recommendations could be completed fairIy easily and quickly by the County crews the projects should be phased as follows: (1) the removal of the weir in CB #24 and the redesign of Briar Hills No. l Pond, (2) the � redesign of Briar Hills No. 4 Pond, and (3} the main trunk system pipe replacement. The evaluation of the results was done assuming that all three . recommendations will be done. The hydrologic and hydraulic modeling �- information, as well as the cost-estimates aze included in the appendices of this report. A summary and comparison of the msts for each recommendation can be found in Table 4. REDESIGN OF BRIAR H1LLS NO. 1 POND Based on the reports of the local residents who have observed the pond during major storm events, the Briar Hills No. l Pond is presendy filling to one-third the level of the pond, which means only 0.1 acre-Eeet of this 0.75 acre-foot pond is being utilized. Therefore, since this "backup" pond is not presenfly functioning I properly, it should be redesigned to function as a detention pond for a smaller I portion of the basin. The easterly portion of the Briaz Hills No.2 development could be diverted from the main trunk system into the Briar Hills No.2 detention pond and a new oudet control structure and pipe could be constructed from the pond to the ravine. The easterly 12 acre portion of the Briar Hills No.2 development contributes the peak flows shown in Table 2 to the main trunk system (see appendix for KCRT'S model runs). Therefore, this diversion would produce a clear reduction of the peak flows to the main trunk system as demonstrated in Table 2. - X 1659121.943 1?I3]/9G ' � SECTION 5 , TABLE 2 Kovacich Drainage Investigation Peak Flow Rates for Briar Hills 2 Basin Return Period Peak Flows Remarks Basin 2- 5- 10- 25- 100- I Descripfion Year Year Year Year Year (cfs) (cfs) (cfs) (cfs) (cfs) Easterly 2.4 3.6 4.4 5.5 7 15 min/historical data portion of Briar Hills No. - I 2 (12 acres) Kovacich 26 39 48 60 78 15 min/historica) data � Study Basin II (280 acres) . Study Basin 23.6 35.4 43.6 54.5 71 Straight subtraction. . minus the easterly portion of the Briar Hills No. 2 Basin The pond bottom should be excavated creating a flat bottom to ensure that the maximum pond volume is achieved. The total cost of this solution is approximately $12,70Q and would provide 0.5 to 0.6 acre-feet of storage replacement for that which is currendy being stored in the intersection during flooding. REDESIGN OF BR1AR HILLS NO. 4 Potv� � - - - � Under current conditions, the Briar Hills No.4 detention pond is not being fully utilized according to residents. In order to maximize the replacement of the storage cunently provided by the intersection during flooding, the flows from the main trunk system could be designed to be partially detained in this pond. The main trunk system could be diverted through Briaz Hills No. 4 detention pond and a new ouflet control struchue and pipe could be constructed to pass flows through the pond. The pond could be excavated 4 feet to an elevation of 361.0 in order to maximize the storage available in the pond. Please see Figure 8 for details of the revisions to the pond and the existing system. Assuming that . the pond is not currenfly being utilized, this option would provide 0.4 acre-feet storage replacement at a total cost of approximately$7,800. MAIN TRUNK SYSTEM PIPE REPLACEMENT X1659121.943 1213U`I6 R. W.Beck 5-2 ' SOLUTION EVAIUATION/RECOMMENDATiONS « The weir in CB #ZA could be removed to eliminate the tailwater affect on the main trunk system at a cost of approximateiy $800. However, the main trunk system presendy does not have sufficient capacity to cazry the peak flow from the 10-year storm event, even with the weir removed from CB#2�. Therefore, the system should be replaced with smooth interior concrete pipe or double wall corrugated polyethylene pipe (CPEP) in order to increase the capacity of the system. The existing structures could be reused. The 10-year peak flow is 48 cfs and since the easterly portion of the Briar Hills No. 2 development will be diverted as discussed above, the peak flow in the main trunk system for the 10- � year event is reduced to 43.6 cfs. If the system were replaced with the same diameter concrete or CPEP a 10-year level of protection would be provided (see � � the Table 3). � Another option is to slipline the CMP pipe with CPEP which would provide a � 5-year level of protection. A profile showing the pipes to be replaced is shown in Figure 6A dL 6B. A summary of the results of the hydraulic analysis of this option is shown in Table 3. An option to replace the lower portion of the system with 48" diameter concrete pipe was also considered. This option would involve decreasing the slope of the pipe and replacing it with 48" diameter concrete pipe through the intersection. i�oweve� as can be seen from the results in Table 3 the improvement for the overall system is not significant but the cost of this option is high {approximateIy $178,200). Therefore,it does not prove to be a reasonable alternative. The cost of replacing the corrugated metal pipe with concrete pipe is approximately $22A,100. 7'he cost of replacing the corrugated metal pipe with CPEP is approximately $179,900, and the rnst of sliplining the pipe is - approximately$121,200. Table 3 Gpacity of Pipe Before the Upstream Catch Basin Overtops I . .. flows in cfs . , • CB 24 Q 9 JB 7 CB 7 CB 6 CB 5 CB 4 IvII-i 1 �eve! of rotedion Existing System 35 Zg 35 � 32 31 -year F.�asting System with Weir Removed >85 64 45 37 37 35 33 31 to 5-year Sliplining System(36"w/31.91'and 30"w >85 69 49 42 39 37 � yea� 2628'�and Replaang Arch Pipe with 36" - Concrete.Using BH#1 pond. Replacing Entire System with Same as >85 >85 61 50 55 52 49 4 10-year F�dsting Diameter Conaete or N-12 Pipe.Using BH�`1 pond. Repladng Lower Portion of the System >85 >85 >85 >85 47 37 33 gl �to 5-year � (through CB�with 48"Conarete.Using BH#1 pond. Bold i�dicates lowest capacity. X1659I21.943 l?I31/96 R. w BeCjC �J-3 , ��Z,Yc��`- R�i,_ �,q .. -Y'-� . Q' �' i- �'11a ' 9 � * �r �� T�� .p — �. ,.ri:'; •—�' t.. " R SECTION 5 The level of protection shown in Table 3 allows no flooding of the roadway. The �, level of protection shown for the proposed recommendations is based upon the peak rates for the siudy basin minus the peak rates of the easterly portion of Briar Hills No. 2 (please refer to Table 2). The level of protection that these recommendations would provide for the Kovacich home is difficult to determine because once the water overtops the drainage system and flows into the , roadway, flooding of the Kovacich home will depend upon the duration of the '� storm and not upon the peak flows or pipe system hydraulics. However if all of the recommendations are completed,based upon our engineering judgment the construction of tkie recommendations would improve the level of protection for �'� the Kovacich home to between a 15 and 20-yeaz storm even� I I Table 4 � ', _ Cost Summary Table � . I i � Options I Briar Hills#1 Pond $12,700 $12,700 $12,700 Briar Hilis#4 Pond $7,800 $7,800 $7,800 Replace Main Trunk System Sliplining Reptace Replace w/CP w/CPEP $121,100 $220,100 $179,900 � Total $141,600 $240,600 �200.400 t , .; 4 ' O / { RECONNAISSANCE REPORT NO. I3 LOWER CEDAR CREEK BASIN � JUNE 1937 � � Natural Resources and Parks Division and Surface Water Management Division ' Kina County, Washinp on � , King Coanty CzecvYnre � -. Tim Hill - King County Council Audrey Gruger, District 1 Cynthia Sullivan, District 2 Bill Reams, District 3 Lois North, District 4 Ron Sims, District 5 Bruce Laing, Disirict 6 Paul Barden, Disirict 7 Bob Grieve, District 8 Gary Grant, District 9 � Department of Public Wor�Cs Par�, Plannin� and Resouroes Don LaBelle, Director Jce Nagel, Director Surfacc Watcr Managemcot Division Natnral Resoumes aad Parlcs Divisioo . Joseph l. Simmler, Divisioa Manab r Russ Cahill, Division Manager � , Jim Kramer, Assistant Division Manager Bilt Joily, Acting Division Manaber Dave C7ark, Manager, River & Water Derek Poon, Chief, Resources Planning Section Resoume Section Bill Ecicel: Manager, Basin Plannina Program Lam Gibbons, Manager, Project Manadement and Desibn Section Contn�buting Staff Contnbuting Staff ' Douo Cfiin, Sr. En�neer Ray Heller, Project Manaoer S: Team Leader Randal! Parsons, Sr. End neer Matthew Ciark, Project Manager Andy Levesque, Sr. L-na neer Robert R Fuerstenberg, Biolobisi & Tearo Leader � Bruce Barlcer, Fn�neer Matthew J. Bruengo, Geologist Amy Stonkus, En�neer L,ee Benda, Geologist Ray Steiper, En�neer Derek Booth, Geologist Pete Ringen, Engineer Dyanne Sheldon, Wetlands Biologist C'indy Baker, Earth Scientist Di Johnson, Plannina Support Technician Robert Radek, Planning Support Technician Randal Bays, Planning Support Technician Fred Bentler, Pianning Support Technician _ Cortsulting Staff Mark Hudson, Plannino Support Technician Sharon Clausen, Planning Support Technician Don Spencer, Associate Geolo�ist, Earth David Truaz, Planning Support Technician Consultants, Inc. Brian Vanderburg, Planning Support Tecfinician John Bethel, Soil Scientist, Earth Carolm M. Byerly, Technical Writer Consultants, Inc. Susanna Homi� Technical Writer V o nia New�nan, Graphic Ariisi Marcia McNulty, Typesetter Mildred Miller, Typesetter Jaki Reed= Tvpesetter , L,sla Lira, Office Technician . Martv Cox, Office Technician � P:CR ' TABLE OF CONTENTS I. SUMMARY 1 II. IN'I'RODUCTION 1 III. FINDINGS IN LOWER CEDAR RIVER BASIN 2 A. Overview of Basin � 2 B. Effects of Urbanization 4 C Specific Problems S . 1. Dninage and flooding probtems 5 ? Damab to property 6 3. Desiruction of habitat 6 IV. RECOMMENDATIONS FOR ACTION 7 A. Reduce landslide hazards 7 B. Reduce erasion and flooding 7 G Prevent futurc erosion aad flooding with appropriate anatysis, 8 planning, and policy development - D. Stop present (and prevent future) damage to habitat 8 by addressing specific pcoblems in stream systems V. MAP 11 APPENDICES: � APPENDIX A: Estimated Costs A-1 APPENDIX B: Capital Improvement Project Ranking B-1 APPEDDIX C: � Detailed Fndin� aad Recommendations G1 ' I_ SUMMARY The Low-er Cedar River Basin, in southwesi Kino County, is unique in its development pat- � terns and the associated environmental problems that appear throughout the basin. Except for the city of Renton and areas on the Cedar River Val(ey floor, most of the development ' in the basin has occurred on the upland plateaus. Mosi of this development is recent and primarily residential. Ia addition, the plateau is the site of numerous sand and gravel mining operations and, in the southern uplands, an abandoned coai mine. Peat is also being mined north of Ouer Lake. In some areas livestock are being raised on small farms; there are no major crop-related agrirultural activities in the basin. i The effects of development are most apparent where storm drainab is routed over the I valley walls. Impenriovs surfaoGs on the pWtean havc increased the rate and volume of storm runof� resulting ia su6�stantial ero6ioq siltatioa, and [looding be[ow. In addi- � tion, erosion and siltation have d.amaged or destroyed habitat ia many tn�butaries, threatening the survival of fish. Habitat and water quality throughout the basin are also threatened by II the filling of wetlands and the presence of laige amounts of domcstic trash in some streams. The reconnaissance team noted that the Peterson Creek system has so far remained in its natural, nearty pristine condition. Maintaining this quality should be a high priority in . future basin planniag capital project prwbrams. � Recommendations ia the Lower Cedar River Basin indude 1) designing and ooastnxtinb appropriatety sized R/D and other drainage facilities; 2) establis�ing siricter land ux policies reb rding floodplains, wetlands, and gravel mining, 3).mnducting more detailed and oomprehensive hydraulic/6ydrologic ana[yses of proposed deve[opments; and 4) pceventing damage to the natural drainage system. The field team aiso recommends � restoriag the habitat of several tn'butaries re.� cleanins p7-;�vel reve�etatin� siream ban and diversif w'n� \ b'1 O O" � b b � 7' Ca streambeds for spawning and� rearing) as well as � proteding the neazty pri�ne quality of Peterson Creel� II. IIVTRODUGTION: Hisiory and Goals of the Progrdm � In 1935 the King County Councit appraved funding for the Planning Division (naw called the Natural Resources and Parks Division� in coordination with the Surface Water Management Divisioa, to mnduct a reconnaissaaee of 29 major drainage basins located in . King County. The effort bep n with an iaitial investib�ation of three basins -- Evans, Soos, and Hylebos Creeks -- ia order to determinc e�sting and potentiai surface water problems and to recommead action to mitiD te and prevent these problems. These initiai investiga- tions used available data and new Geld observations to examine geology, hydrology, and habitat conditions in each basin_ Fndinb from theu three basins led the King County Counal to adopt Resolution 6013 in April 1936, calling for reconnaissance to be cornpleted on the remaining 26 basins. The Basin Reconnaissance Program, wfiich was subsequentty csiablished, is naw an important ele- ment of surface w-ater management. The goals of the pro�ara are to provide useful data w-ith regard to 1) critical problems needing immediate solutions� 2) basin characterisiics for use in the preparation of detailed basin management plans, and 3) capital costs associated w7th the early resolutioa of drainage and problea� The reconnaissance reports are intended to pmvide an evaluation of present drainage con- ditions in the County in order to transmit information to policymakers to aid them in developing more detailed reb latory measures and specific capital impravement plans. They are not intended to axribe in any conclusive manner the causes of drainaoe or erosion ' P:LC i - L.ower Cedar River I3asin I (continued) problems; instead, they are to be used as initial surveys from wfiich choices for subse uent - 9 detailed eno neering and other professionai environmentat analvses may be made. Due to the limited amount of time available for the field work in each basin, the reports must be viewed as descriptive environmental narratives rather than as final engineering eonclusions. Recommendations contained in each report provide a description of potential mitib tive measures for each particufar basin; these measures might provide maximum environmental I protection through capital project construction or development approval conditions. The � appropriate extent of such measures w-ill be decided on a case-by-case basis by County offi- cials responsible for reviewing appiications for permit appravals and for choosing among competing projects for public construction. Nothino in the reports is intended to substitute for a more thorouah environmental and eno neering analysis possible on a site-specific basis for anv proposal. III. I��IDINGS IN LOWER CEDAR RIVER BASIN , � The field reconnaissance of Lower Cedar River Basin was conducted in Januarv 1937 bv � Rot�ert R. Fuerstenber� biologisr Bruce L Barlcer, eno neer and Lee Benda, geologist.� Their Cndin� and recommendations are presented here. A Ovetview of Low�er Cedar Riwer Basin The lou-er Cedar River Basin is located in southwest King Couaty and is 27 square . miles in area. It extends southeasi from the mouth of the Cedar River on Lake ' Washinoton to approximately river mile 14.0. The boundary to the northeast is marked by a ridbetop connectinD the city of Renton to WeUster and Franklin Lakes; the boundary to the southwest runs along Petrovitsky Road to Lake Youn�,s. - Renton is the only incorporated area in the basin. Other populatio� centers include Faimood, Maplewood Heiahts, and Maple VaIley. Ezcept for the city of Renton, most oC the residential concentrations are located on the upland plateaus overlooking the - Cedar River Valley. These upiand developments are recent compared to the smaller � established communities on the valley floor. The basin lies w-ithin portions of three K[n� County plannina areas: New-castle ia the northeast (wfiich includes Renton), Tahoma-Raven Heiohts in the east, and Soos Creek (the la best of the three) in the �,;est. Rural areas exist on the val(ey floor on both sides of the Low-er Cedar River, from approximately river mile 5.50 to 13.00. These are limited to pastureland for horse.s, cov�s, and some sheep and several sma11 "u-pick" fruit and ve�etable farms_ Similar areas are located on the southern uplands above the reach from river mile 5.50 to 7.00 and in the Lake Desire-Otter Lake area. The plateau is also the site of sand and gravel mininb operations and, in the southem uplands, of the abandoned Fre King Coal Mine. Peat deposits exist west of Lake Desire and north and south o[ Otter Lake, and peai mininp is being carried oui north o[ Otter Lake. Present zonin� altows [or urban and suburfian densities throuohout much of the basin; particu[arly on the upland plateaus and in the Cedar River Valley from its mouth to appoximately river mile 6.50. Population projections for the year 2000 in the three y plannign areas containing the L.ower Cedar Basin are over 311,00�, an increase of 47 ``,1; P:LC ? ' Lower Cedar River E3asin ' (continued) ' percent from the present. Most of �his growih w�ill occur in the Soos Creek Plannino i Area. � Domiaant g�eo(ogical and geomorphic features. The geology of the Lrnver Cedar River I Basin is diverse. Geoloaical formations exposed atong the valtey include sedimentary rocks: undifferentiated older glacial drift, extensive ground moraine deposits, recent alluvium along the Cedar River, and landslide deposits along the river and its tribu- taries. The sedimentary rocks, composed of rnoderately dipping sandstones, con- glomerates, mudsiones, and shales, are expc�sed locally along the diffs of the Cedar River Vallev near the mouth oE the Cedar River. In addition, the Renton formation: � composed of sandstones, mudstones, and shales with periodic deposits of coal, is also exposed along the lower portion of the L,ower Cedar River Valley. Undifferentiated glacial deposits [ound here are composed of three or more till sheets, glaciafluvial sand and gravel, glacialacustrine day, and sand, and non-+clacial sand, clay _ and thin peat. These ]ie aver the sedimentary rock focmations and are besi exposed � in cross-section along the cliffs of the main valley and major tributaries. - The morpholop of the Lower Cedar River Basin is dominated by the valley formed II by the Cedar River. Valley walls are steep c[iffs formed by landslides in b acial sedi- ' ' ments. A once extensive and meandering River, wfiich created a w-ide valley [loor as it cut its way wesi.ti-ard, the Cedar today is diked for most of its lenp h throu�h the low-er valley. A narrow but ea-tensive band of landslide deposits e�;ists atong the steep cliffs of the main river and its rnajor tributaries� The landslide deposits consist of _ deformed blocks of �lacial sediments and mlluvium derived from slides or mass flawage, such as landslides and debris fla►vs. Recent alluvial deposits Fll the valfey and major tributaries. Small, composite, al[uvial debris fans exist at the mouths of the lar�est tributaries. Closed depressions, principalty in the uplands, have lacusirine and peat deposits. The Lower Cedar River Valley has a high potential for erosion due to steep slopes and the existence of a clay layer that pro�otes soil failures. In addition, the confined nature of tributary channels between steep hillslopes promotes bank erosion during high ❑ows. Numerous recent landstides are evident along cliffs of many of the steep tributaries and along the main stem of the Cedar River. These have been accelerated � by the removal of vegetation and the routing of mnceatrated storm flows over steep slopes in areas where development has occurred. Hydrobgic aod Lydrautic c6araderistics. The Cedar River Basin is coanposed of a complex drainace network consistinb of the Cedar River and i7 tributaries. The la ber tributaries begin in lakes or w-etlands on the blutfs and flow throubh relatively tlat, stab{e channels to ihe edoe of the Cedar River Valley, then plun�e down to the valley floor throuah steep, erodible ravines. Tributaries o[ this type such as Tributary 0.� (with headw-aters at Wetland 3111) and Tributary 0323 (which begins at Lake Desire� are found on the south side of the Cedar River. Another type of tributary collects surface runoCf from urbanized areas, pastureland; and wooded areas. Tributaries 030?, 0307, and 0312 are er•amples of this type of tributarv. The�� are intermittent (dependin� on rain[all), shorter in leno h, flaw through shallower channels that are steeper at the bluffs and lransport more material during times of P:LC 3 ' L,ower Cedar River Basin (continued) high flows. Some of the worst problems located during Cield investib tion (see Appendix C for a full listinp) occur on this type of tributary. Catchments S, 6, and 12 have very infiltrative soils. Urban developments hvae utitized R/D poinds to effectively infiltrate al! ufian runoff before it reaches the valley hil(slopes. The infiltrated runoff then reappears as sprin�. Two large lakes (Desire and Otter), topether with four smaller ones (Shady, Peterson, Webster, and Francis) lie in the southeast third of the basin. Numerous large wetland areas exist in this section as well. "I'6e field team identified 10 potentiai wetland sites ihat had not been previously identified in the Sensitive Areas Map Folio (SAM�. The system of lakes and wetlands ia this area effectivety buffers the high flaws drainina to these tributaries. Habitat c6aracteristics. With few exceptions, usable Cish habitat ezisis only in peren- nial streams (i.e, Trib. 0302, 030�, 0305, 0328, and possibly 0303). In other sireams � (e.g., Trib. 030� and 0310), steep gradients preclude fish use. Steep gradients also reduce fish use in the perennial systems (ezcept for Trib. 0323). Habitat is in various stages of degradation in these systems; poots are beinp filled and oravels and debris shift rea larly. In Tributary 0323 (Peterson Creek), hawever, habitat diversity is extensive, and the channel is not seriously degraded. At this location the field team . observed at least three species of salmonoids. In generat, the mosi diversc and least disturbed habitat in a tributary system occurs in the la be x-eNand areas in the southeast third of the basin. Usable habitat for anadromous fish is found in the la�-�adient portions of sireams where channels cross the Cedar River Valley floor. In these reaches, however, onlv spawnino habitat is likely to be available, as the pools and woody debris necessary for successful rearina either do not exist or are quite limited. Ercellent spawning and rearing areas ezist � where poois and riffles are extensive, instream cover and bank vegetation are intact, and diversity of habitat types is abundant. � B. Et[eds of UifianiTation in t6e Basin Floodin� erosion, and the degradation of habitat associated with development in the Lower Cedar River Basin are most apparent where development has eliminated vege- tation along the edges of the valley and where stormwater has been routed down channels and sw-a[es. The removal of vegetation, s�ch as trees, above and below the edges o[ valley v+-alts, as w-e[I az the discha bing of stormw-ater aver the valley walt, has resulted in tension cracks and landslides that are endangering some houses. The sedi- ments from these failures are depositing in streams and on valley [ioors and damao np �sh habitat and private property. Discha oing stormwater from increased impervious areas into.steep tributary channels and swales is seriously destabiliz�ng channels and valley w�lls; this in tum res�lts in channel downcuttin;, bank erosion, and landslides. The sediments from these problems often degrade fish habitat and settle out on pri- vate property along the valley floor. Two serious instances of development-related erosion occurred during the Navember 1936 storm: 1) culverts rerouting the stream were plu�ed, causing the formation of a new channel that destroyed portions of roads on Tributary 0314; and 2) new, uncom- .� P:LC 4 ' Lower Cedar River Basin , _ (continued) pacted fill adjacent to new residences near collection point 5 w-as w-ashed partly away durina the storm, causing landsliding and b tlying. Future problems will be similar to these, as commercial and residential developments i increase flow rates and volumes by decreasing natural storage and inGitration. This is expected to occur if wetlands on the upper plateau are encroached upon or lost (e_b., on Trib. 0304 at RM 2.30 and on Trib_ 030aA ai Rm 1.60). The preservation of r�etlands and streambank vegetation and ihe attenuation of storm flo�s are essentiaf in this basin. G Spccific Problems Identified The steep valley sideslopes through wfiich streams pass and the often dense upland developroent result in a number of similar problems that repeat themselves throughout _ the Lawer Cedar River Basin. The mosi si�ificant of these are outlined and discussed belaw. � 1. Drainage and flooding problems are often the result of scveral rnnditioos: a Undcrsized culverts and inadequatc cntranc� stnsctures. The most notable area is on Tributary 0306 at river mile 30, where a culvert here v�-as blocked by debris carried dow;nstream by the stream and caused erosion and floodinb of Fairwood Gdf Course. The blockao was compounded by the . fact that the culvert was undersized; the problem wilt worsen as flaws increase from upstream development. b. Seriovs iastream ero6ioa and subsoqucnt downstream sedimeatation. These have been caused by three main factors: 1) runoff from residential developmeats on the bluffs above the valley, ?) compacted pastureland due � to livestock, and 3) runoff from impervious areas oriDinatinD at �ravel pits These problems will continue and w-orsen uutil mitia tive measures are taken. (See Appendix C for speciGc examples.) � c. Undersiz�ed rechanne(i�ed streams. Tributaries on the vallev floor are too smali to carry the increased flo�s orio nating in developed residential areas . along the top of the bluffs. For ezample, Tnbutary 0302 at river mile �5, the channel alonb Maple�ood Golf Coucse, overtops and floods during storms. � d. Coosttuction in welland and fioodplain arcas, Many of the wetlands on the south side of the Cedar River are peat bo� and roads huilt through them continue to settle each year, increasing the amount ot Cloodina on the road. For example, the road crossing with Tributary 03�3B north of Lake Desire � will experience more severe flooding as the road settles. e. Disc6arging of storm�rater at t6e top of stecp banks. At river mile 2.20 on the Cedar Ri��er a trailer park (constructed on the ed�e of the cli[� • dixharges its drainage dow-n the valley v��- Increased tlows erode the steep valley, depositing sediments on the valley floor, blockinb channels and causing floodin�. These problems wilt eventually stabilize, bui only alter a large quantity of soil has been eroded. P_LC 5 1 Lower Cedar River Basin . (continued) 2 Damage to property is being causcd by t�rce [actors: � Landslides and potential landstides. Landslides are accelerated by the remwal of vegetation on steep slopes in preparation for residential construction and/or by the routing of storm flows over hillslopes. For example, a large landslide has already occurred in the front yard of a resi- dence on the Cedar River at river mile 7.30. b. Sedimeatation (from landslides). Sedimentation and channel and bank ero- . sion are damap ng private property alonb the valley [loor (Trib. 0?99 and 0310). c I�iooding duriag stocros. Flooding has been brouDht on by the effects of development and associated chanbes to the natural drainage systems in the basin. (See "B" above.) � 3. Destruetion of habitat is Ueing caused by four eoc�ditioos: . a Sedimentation of pools aad ritfles and eementing of �rav�els. These problems, the �esult of severe erosion and the transport of bedloed material, have been caused by upland developments in the basin and the presence of associated impervious surfaces, which increase the rate and quantity of surface runo[f. Sedimentation and cementing of gravels in streambeds destroy natura! spaw-nino and rearing habitat. On Tn�hutary � 0307 at river mile .40 and Tributary 0305 at river miles .95, 1.?0, and 1.70, recent high flow-s have eroded the strean�bed at least one foot, contributina to a serious seltation problem downstream. Heaw bedload transport is evi- dent in all svstems of the basin ezcept Tributary 03?3. In Tributan+ 0_�3 at river mile .�, fne sediments are accumulating in gravels that may be used by resident fish. In Tnbutary 030� between river miles .95 and 1.20, pools are beinD CUed by sands and grave(s and rearing habitat is beine rapidly lost. - . b. (�annelizatioa of atream bcds. Loss of habitat ihrough channelization has occurred in all ihe major streaars of the basin, but most noticeably in those reaches that cross the valley [loor. These reaches lack habitat diversity, reducing fish use for spawning and rearino. Channelization has damaged or destroyed. habitat in severat reaches that were once heavily used by rsh; ' these include Tributary 030? betv�een river mile 30 and 40, Tributary 0',0# between river miles .OS and .13. Tributarv 0305 t,etween river mile .'?0 and .75, and Tributary 03� from river mile 1.10 to 1.40. These svstems cannot . afford a further reduction of habitat and still remain viable Cshery resour- ces. c. The aavmulation o[ trash in stream beds. This problem occurs in close prozimity to residential areas. Trash deDrades w-ater quality and is visualt� unpleasant. Tires: appliances, furniture, and other trash have been thrown into Tributarv 030? at river miles 1.00 and 1.10 and in Tributarv 0303 at river mile .35. P:LC 6 ' � L.ower Cedar River &uin (continued) d. Wetland encroachmenG Eneroachment destrovs habitat and eliminates natural water Cltration and storape for surface runoff. E�,-amples of this problem were observed on Tributary 0304 at river mile ?.�0: Tributary 0�03 at .80, and Tributary 030=tA at river mile 1_30. Many w-etlands have already been completely lost through 6lting, for example on Tributary 0306A at river mile S5. Suspected violations were forwarded to Building and Land Development for enfomement. IV. RECOh�fII1DATIONS FOR ACIZON The primarn recommendations for action in the Lower Cedar River Basin addresses current severe probtems refated to erosion, habitat destruction, and flooding. Prevention of these problems will be accomplished by controllino locations and densities of new development and providing adequate R/D facilities for stormw-ater. A Reduoe tandslide hazards by: ' � 1. Indudiag seasitiv�e areas not previou.sly mapped on the Sensitive Areas Map I'�oiio (SAMF} See Appendix C for a full lisiing of sensitive areas. 2 Fstablishing building setbacrs along diffs and native ��owth protection easements along sreep ravines. 3. Dixouraging or eliminating the routing of stormwater over cliffs, unless adequate tiahtline systems can be constructed to convey flo�s in a sa[e, nonerosive manner " to the bottom of cliffs. 4. Decreasins pcalc flows by constructing ta ber R/D facilities to lessen the lanclslide and erosioa occurrence atong tributary slopes. ` B. Reduce erosion and flooding in the basin by improviag surface water maaagemen� 1. Diiect the Fac�ities Management Section of the Surface Water Management Division to evaluate e�astiag storm�eteation and oom++eyaace facailities to deter- mine whether they are propedy sized to meet current standards. Evaluation should be�n with all singie-orifice R/D facitities. 2 C,00sider arcas ot6er thaa weQands as re�oaal stocm-detentioa facilities. Tributary Oi00 at river mile .4? is the site for a pmposed dam, for example. 3. Utilize e�dsiing IovNer quatity weilands (those ratod othcr t6an #1) as regiona! slorm-dctention facitities. Wetlands 3102 and 3142 could provide more live storaoe, for er•ample. 4. Review chanael and cuh+�eert capacity for coaveying eusting and future iunoff, and estaUlish floodplain areas in re�ons of slipht gadient for existing and future runo[f conditions. 5. Promote the inCilttation of surface vrdter thrwgL the use of retention facilitics aod opca channels insiead of pipes where the soil and slope conditions permit. Collection points 5, 6, and 12 on plateaus have such soil conditions. P:LC 7 1 Lower Cedar River Basin (continued) G Pr�event future problems o[ ettuion and flooding with appropriate aaalysis, planning, and policy dcvelopment related to surface water managemeat: 1. Cond�ct a detaikd, oompreheasive hydrauGc/hydrologic anaIysis of any propc�sed devebpments to determine impacts on the drainage courses do„-nstream. This is especially critical for areas on the�upper bluffs and plateau, which drain over steep, sensitive banks above the Cedar River. 2 Cooduct a study of the impact of locating inf'dtration ponds utilized near the ed�e of the bluffs to determine their effect on seepage faces on the lower face of the bluffs. This might be accomplished with a computer-based numerical model of the broundw-ater fla►�. 3. Require the tig�tlining of storm drainage dc�vvn steep or seasitiv�e slopes when they cannot be directed away from the slopes. T'his is done by piping the flow daw-n the slope and dixharging it at the bottom with adequate energy dissipation. Many of the. intermittent tributaries flowino dawn the banks should be tiahtlined as urban development increases flow to them. 4. Constn�ct new R/D ponds wiEh ftlter berms to improve water quality and reduce _ Cine sediment laads New R/D ponds should have two cells with gravel-berm filters and vegetated swales at the inlet and outlet. Consider Tributaries 030#, 0304A 0302, and 0303 as sites for this type of facility in order enhance w-ater quatity. �� 5. Maintain-natural vegetatioa on streambanks and [loodplains. This is especially important for relatively flat channels flaa-inb on the plateau before thev reanc �he steep bluffs because these channels and their [loodplains w-ill attenuate flaws daring times of heavy runoff. � � 6. Maintain bu[fer areas around w�etlands. Many of the tn�butaries on the south side of the Cedar RiveF headwater at wetlands. These wetlands act as natural storaa areas during storms. 7. Recvaluate King County policy reg�rding permitting for grav�el mining on steep, sensitive slopes. 8_ Indude the dty of Rcation in future interiocal agreemeats for plannino and capi- tat impcovement projects where city and county interests overiap. D_ Eliminate pmseut damage to habitat and prevent future damagc by addressing spocific problcros in the stream systems. The fotlowing activities should be coordinated amono King County. the Muckleshoot Indian Tribe, and State Departments o[ Fisheries and Game: 1. Reduce damaging storm tlocvs with greater detention volume and lower release rates at upuream developments. 2 Implement resioratioa projec4s on Tributaries 0.� (river mile .00-.?0), Tributary . 0305 (river mile .?0-.30); Tributary 0303 (river mile .25-.35), and Tributary 03?3 .� (river mile 1.10 -1.40): P:LC 3 ' Loa;er Cedar River Basin (continued) a On Tnbutary Q304: Cleaa streambed graveis, add habitat and bed-control weirs, and plant bank vegetation for shade. b. On Tnbutary OCiOS: Construct a new channet and mave stream from road- side channel to its new location on adjacent lands. Implement a full restoration project to provide channel meanders, habitat structures, pool/riffle enhancement, streambed gravel replacement, and revegetation. c. On Tn'butary 0303: Mave stream from present channeI to a location further north, away from the roadside. If relocation is not possible, these minimum steps should be taken: Add habitat structure to existing channel w-ith root masses, dellectors, boulder clusters, and other features; revegetate channel banks with shrubs and small trees; enhance stream crossin�s with bottomiess P�Pe arches. _ d. On Tn'butary O(328 (Petezsoa Crack): Add habitat structure by reptacing tf�e straight, shortened channel with a more natural, meandering one; place habitat structures (such as root masses, detlectors, caver lo�s; and boulder clusters) throughout the channel; and revegetate banks with shrubs common to adjacent riparian zones (salmonberry, ninebark, or dogwood, for er.ample). 3. Proted the Pcterson Creef system (Tnb. 0:328) in its pceseat, near pristine state. This will include not only the restoration outlined in section A aboves but atso the adoption of land use management regulations to prevent future habitat desiruction: a Protect all c�sting wetlaads within the subcatchmeats of Pete�soa Creelc. Employ wetland buffers at least 100 feet w-ide without exception. b. Restrict devebpmeot in tLc critiral headvrater area (drainage, habitat, water quaLtp) barnded by Lalce Desim, Otter Iakq and Peteisoa Lake to rural de�ities. ' e. Designate and p�ted streamside maaa�gement zooes of at least 100 feet from the ordinary high-water mark (OHWM) along the main stem of the creek Use 25 feet from the OHWM on tributaries. _ d. Preseivc floodplains and their forests for dynamic retention of sediments and water. e. Restiict vebetation remov�al ia su+eamsidejwctland management zones. � � �e R/D fac�ities to store the 100-year storm at a tvvo-to-Gve-year retease rate. Use the tw�ocet! type of pond with a forebay, a gravet filter, and a vegetated sw�le outftaw where [easible. gr Regulate more closely all sept�c taaic and drain�eld iastallatioos, as well as maintenance sc6edules, particulady in the Lake Desire, Otter Lake, and Peterson Lake drainage areas. . P:LC � 9 ' Lower Cedar River Basin (continued) _. h. Woric with t6e Statc Department of Ecology to establish miaimum siream- tlow requircments for Peterson Creek and Lake Desire tributary. 4. Dc.'velop and promote public education and involvement programs for basin aw-areness. Work with schools; environmental groups, and the civic and business communities to conduct educational and restoration proarams. P:LC 10 � ' � , �. . . � � . ; .. „ , . • I�' '� .� , , �." , ' F �' , LOWER CEDAR RIVER BASIN �I � �Y� -�� r � ' ,� ',, � � -•_• ,-_ ` N - '�' ..� • , �w Basin Boundary __. _, � ' /' '.. � ' . ,��, ' . . � � `�, •�� , �.. Subcatchment Boundary � � : '\ 1 i '`�, t ..`..; .. • • .. '`. .� ., . `, � � . r �2 Collection Point (�, ,�. . '1.' ' , .* . �� , ` __�:�i' -�.1 Stream °' I � I � •� � _ . i<'' • ; . '., . ' • 1 •'' 4'`y�' '' �•; �,- -" • : , . �. 0299 Tributary Number Iy ' �� .• ,..' ,., ^ ; ' ♦ i ` _ ,r ;�:'�; .,, �; •�� 'M�. � . : :� i° �3115 Proposed Project � � " ;{r� .I ��-:�� { _J. :�� . �"� ,I ' + i wDa � — . _.._i — 0 1 2 li \ � . , •, Miles � _. pnt0 i. ,'�' u H , '� ---- ' A � . " ' ,�.,. I-_•�„ i , ;'. .�Y;� � , s a � , JuIY.1987 1%�i' �.�•.V:� .M�.. R T' O N � �..��. . , `�. .� �T �' 'y + . .��. . � ' � 'J � 7 �.nL��rr�.\ - -:w : �� .._. _ �� ......_�� .. .._r , ,. x �--:�. .�— . : _ __ . : .�,.,;.. �. � �.a . 19 .,,�� 1 ` �' �. I ~� ' i' , , �., ,, : �.: � -=�; • _ �:�� ... , „ _ s, ;.. i � . / �.. , \, . •., �', . , r / � �--" . � . ,... 31 � , , . . � •;. �: � OS . Zp a . . . . � �, ...---�—: s ^, ^� '..;..:. . . , . _...�.._. .,�.r '� 7 , yA 4 �r. � . I ... t�.:I...', �4` O t �-'O' „_ .«., � ,,,,,,,� `� a 1a °��i .�', (j) `1 f . � • , . �`1�9 w$ �,t ti �°w o � , H ° r�' 3117� ; . . 11 ; . � . � �� . 9 , �'��o ". s �, `' ,"•" *" � ,. . , ,. ' . •�-w�, , 1 , � . , � `; .._...... _ 3121. ,� ' � �.: !. ' ��. . 3118 �°� - f }�� .,i � � � j I, .`` q,; � � Z�� .r• ,•.'n. p 1 � / � I i„�,�i��n `,� � �.'3122 1 ' 3116 p3 _.. �4 0 �,.. � ' - .a � ��""; �r � �f�. Jj � ' ..r,._. .Q o�; .;t , .. --... i .;.i' � , � `; ��- _... . �,.,' ,� ° � � . r • i.,� . , o�" • :. ,, . • r:..�, •b2'9'� �`L: , I . . . . . � � 03? '.:,�r.,; ,� i 31.11 °� � '.i � . :� � �'' . . I r :xr ,� � , __ .... .. ... ..' ___.�.__._..:y. � ��:�;., ,..;,,:,,,; 21 "a nP . \� . r � .rr., � .. M - ��*j).:; I � . � , � ,� . �w� �' � ,� : 3115 .. I j' i",�� :Gy o� ^�� Ye: I ' .. .. � •� ` , r' , �r1,�,.-:••:' � . ...a � I � ! . � r�:•�r.a, ^�� 1� � `�C'`.� �,.-_...� p � i � I . • �,: , c a dk'{e�rrla�vi!A'�ehb ,..� O� � � �^' ,I , . ' ::.».;.,. ,'��x:� 1 12 3114A , . . : �,� � :� i �- • • . ' .. ._. • ...I .._ � ' '•,i ...._ .____... _. ..,�. .. ._ . .. . ._ :;�R;' : � • 'r?t'f;�;: \ ;� . ! .a•• :. ., „ � \, � , ... .... � : � '�a�Y;� . " � .. �'.Mr�At'/a".�y � ,� ...� . . . . ' , ^ .41�+.a , J� �'lY'..� � •.I..' . . . . '`1 .!' ' . � ��y` \\ �.� :'� I �• �� I 1 y ^ , �� I .1 11.• •• I .�; ..• .`� . ... .\ . _....... . . \ .;1• . (,�`� .� �� .. ... . � ' . .. , � . APPEPIDiX A • ES'I'IMATEU COSTS: PRUI'OSED CAPITAL 1MPI20VEMENT PROJL-'CTS � LOWL-"I2 CL-'DAR CRELK BASIN " Indicetea project was�identified by SuMace Water Management otlice prior to roconneissance. _ NOTE: All pro)ects are located on map � tnclu0ed in this report. Project Coliect. ' E.stim�tcd Costs N��mher Point Pmiect Descrintion Problem llddro�.scd �nd Comments :�105• 10 Cnhnncc 2200' of Trib. 0305 from Mitigntcs flooding of King $115,000 Ced�tr River to Elliot Bridge. County park lnnd. (NOTE: This projcct w�s proposed by Surface Watcc M�nngement, is in the C��51�^,ti � phAse, �nd will be � construc;ted by 1939.) 3109' 10 Sccure c�sements to wetlAnd loc�tcd � Better utilizcs wetland's stor��e $I4G,000 • in C�scnde�Pnrk nnd construct n Uerm clpncity to �ddress peak flows from , at the outict. Repl�ce existing surrounding urbnn flren. cntch h�sins with contrnl structures. Pmject should hc justific;d hy n . hnsin study. Wetlaind rnted #2. (This wetl�nd will requirc furtltcr biolo�icril cvalut�tion befot�: R/D dusign und co.nstn�ction.) , I':LC,AP/1 A-] � Project Collect. . ' I3stimated Costs Number Point Proiect Description Prohlem /lddre��.sed and Commc;nts 3111 Secure e�sements to outlet to Francis Will provide �dditional storage $175,000 (Wetl�nd I.xike nnd 1100' of chnnnr.l from Inke to miti.g7te �nticip�ted future 3136) to SE 134th St. Construct a weir to increased flows. � rnisc l�ke level 1', nnd enhance 1100' of Trih. 0317. Sitould hc justified by n bnsin pinn. Weti�nd rntcd #1. (Tltis wetinnd will roc�uirc furthcr biolo�icnl evnluation heEore R/D design tin� constivction.) 3112 19 Sccuro cnscmcnt for outict to wetland Will provida ndditions�l stornge $117,000 (Wctland �nd replace cxisting w�ir witli � for untic:ipltcd future peak flows. 3143) , cbncrete-slottcd wnir. Should be justified by � basin pl�n. Wetl�nd nited #2. (ThiS wetlnnd will require further biological ev��untion Uefore R/D d�sign und construction. 3114' Secure ci�sem�nt to Wcllflnd 3150 and Addres.ses nnciciputed increases in $134,000 (Wetl�nd construct n contninment Nerm nnd [low cfluse;cl hy d�velopment. 3150) control structure nt th� outict. I'rojeet should be justified by n hasin plan. Wctlnnd r�tcd #2. ('1'his wetlnnd will rcquire� furtlter • , hiologicnl cvaluntion bu[oru R/D design nnd construciton.) 3115 13 Instnll dctcntion pond �nd 1,000' Miti�atcs scvcrc crosion and $3G1,000 of ti�htlinc. Projcct is indepcn- flooding durin; times of high dently justifiable. flows. I':I.C.APA A-2 �� , � Projcct Collcct. Estimated ('osts Numhcr Paint Proicct Descrintion Prol�lcm �lddre�,scd �nd Comments 3ll( 21 � R�ise existing ro�d emhankment Mitig�tes senson�l flooding of I.��ke $73,000 2-4'. 1'roject should bc indepen- Desire Ur. SC cnused by road bed dently justifi�Ule. (Refer to settiing in the pelt bog. ' Ro�ds Division.) II 3117 16 Install 1,400' of tightline, a Mitigntes severe erosion, scdiments $501,000 I scdimcnt trup, And 700' o[ channcl dcposited on Counry ro�ds, �nd I from Joncs Rci. to CcdAr River. [looding during times of hi�h Projcct is indepcndently justi• Elows. Eiublc. 311�4 10 (nstnll 300' of 3h" culvert, n new Will prevent blockl�e of culvert $47,000 inlet 4tructure, mnnhote, �nd c�tc1� and the s►ccompflnying flooding and b�isin. Projeet is ind�pendenHy erosion of I;�invood Ciol[ Course �nd justifi�il�la. mobil� hom� p7rk below. 3(19 4 Construct a detention d�m nnd Project locntion is idenl l�ecausC 51,59,000 � control �tructure in n�deep� it �ddresses flows from n Inrge chnnnelizcd tcction of 1'rib. residenti�l nren beforc they reflch Q3p0. Project is ind�pcndently the steep, se;nsitive nrc� next to justifiAhle. , the Cedar River. 3120 15 Construrt n �:dimcntntion pond rind Mitigltcs [looding of residcnce flnd S1G3,000 1,00�' of channcl from Joncs Rd, to sodiment dcposition on Jones Itd. . Cudnr Rivur. ProjCct is indepen- duntly justi[i�btc. . P:1.G.APA ' A•3 � Project Colicct. Cstimatcd Costs Numher Point Proicct Dc�scription Prohlcm Addrex5ed �nd Comments 3121 7 Scc:ure ��sement to weti�►nd �nd �on- Addresses incre;nsed flows in Trib. $;�71,000 (Wetl�nd stcuct t� contflinment horm nnd concrcte 0304 nn�i 0304/1 from residenti�l 3102) wuir nt outlet. Projcct should be developments. � justificd Uy h bnsin pinn. Wc:tl�nd r�tcd #2, Biologicnl ns.sc:�,sment is n�cded to nssure th�t ,this projcct • does not decre�se hs�Uitat vntucs. 312? 11 Purchate eai4tin� ponds on P�itwood Mitifi:►tes flooding nnd erosion $342,000 Golf Course and expflnd to provide downstream. gret�tcr flow dctention. Project is independently justifinble.. P:LC.APA A-4 �. ---- - __ APPENDIX B CAPITAL IMPROVEMENT PROJECT RANKING LOWER CEDAR RIVER BASIN Prior to the L,ower Cedar River Basin field reconnaissancc, 1? projects had been identiCed and _ rated usino the CIP selection criteria developed by the Surface Water Management (SWM) and Natural Resources and Parks Divisions. Followinb the reconnaissance, 13 projects remain proposed for this area. T'hey indude eight new, previously unidentified and unrated projects. These displace seven prcwiously selected projects, which were eliminated based on the consensus of the recon- naissance team. Projects were eliminated for several reasons: tw-o sites v�ere annexed by the city of Renton, tr�o projects w-ere found to be unnecessary, two sites were categorized as ,�1 wetlands (and are�ineli�ble), and one project was determined to be infeasible. The previous SWM capital impmvement project list for the Law-er Cedar River Basin had an esti- mated cost of S?,710,000, while the revised list increases to an estimated cost of S2,7S4,000. This 3 percent increase in estimated capital co6ts is due to the addition of projects after the reconnaissance. The follawing tabte summarizes the scores and co6ts for the CIPs propo6ed for the �er Cedar - River Basin. These projects were rated accordina to previously establ'uhed SWM Pro�am �tizen Advisory Coromittee criteria. The projects ranked below are those for wfiich the first rating queuion, ELEMENT 1: "GO/NO GO; could be ansu-ered affirmatively. Projects v�ith scores ot 100 or hi�her can be rnnsidered now for merging into the "live" CIP list. RANK PROJECT NO. SCORE � COST ' 1 � 31?? 103 534�000 _ 2 3113 90 37,000 � 3 31� 7S 163,000 4 3109` 67 136,000 5 31?1 65 371,000 . 6 3117 60 501,000 7 3115 60 361=000 S 3116 55 73,000 9 3114s �3 134.000 10 3111s 2S 175,OOQ � 11 3112` 17 117,000 1? 3119` 15 159.000 ' 13 3105 1? 115.000 i TOTAL S�,734,000 . , • Projects proposed prior to the Reconnaissance Program �' P:LC.APB B-1 ' . . � APPENDIX C DETAILED FINDINGS AND RECOMMCI�iDATIONS ' •LOWER CCDAR RIVER BASIN " All ilems lieted here are located on final dlsplay mapa In the otQces ot SurlaCe Water Manaqement, Building and . I Land �evelopment, anC Basin Plannln9, I Trib. �C Collect. Existing Anticiplted Item' Rivcr Mile Point C��tet�Ory Prop. Pro't. Conditions nnd Prohlems Conditions �nd Problems Recommendations 1 -- 5 Geology � Gullying and lundslidos in Continued erosion. Recompact fill, revegetate, uncompncted fill in new and drain adequatcly. development near edge of steep h�llslope, 2 -- 13 Geolofiy Small landslide h�s formed � None (natural fAilure). None. debris flow (11/3G). �Sedimentation in yard of residence. 3 0299 4 Geolo6ry 1.,��ndslides in sedimentnry NAtur�l fnilure. � None. RM 2.G rock in cutbanks adj�cent to rnllroad. 4 0299 16 Geology Druinage from residcnti�l Incrensing erosion. Provide adequate R/D to RM 9.G5 area is resulting in attenuate flows. gullying in awAle. , . . P: LC.APC C 1 � Trib. � Collect. Existing Anticipated Item River Mite Point CatefiOry Prop. Proi. Conditions nnd Problems Conditions and Problems Recommendations 5 0299 18 Gcology Horse farm in upl�nds It1s Continued high erosion and Develop R/D at horse farm RM 12.1 'created extensive imper- sedimcntation. to attenuate pcak flows. vious surfAces, resulting See Project 3115. in chunnel scour, bank erosion, landsiides, nnd scdimentation at mouth�of busin. Residence overcome � with sediment. . � 6 -- 13 Gevlogy L,andslide terrain for s��le Site of future mass erosion. Prohibit developmcnt here. by realtors. High risk for Notify Building and L.�nd IAndsiides, flooding (from Development. Add area to springs). SAMF. 7 -• 7 Geology Large-scale landsides Natural process. None. adjacent to Cedar River due to sprin�s �nd cutting of toeslopcs by streams. Appears to be naturnl. ' 8 -- 2 Geoivgy � Gullying in vatiey wall, Unknown. Nonc. possibly from nfltur�l springs. 9 -- 14 Geology Landslide debris Clow from Existing tension cracks Reve�etate hillslope with residence on SE 147th PI., indicate future instability. trees and shrubs. � Renton. P: LC.APC C-2 � � Trib. & Collect. Existing AnticipAted Item River Mile Point Cate�ory Prop. Proi. Conditions And Problems Conditions and Problems Recommendations 10 0299.1A 21 Hydrology 3116 Frequent flooding o[ Road located on top of peat Elevate the road 3-4' by RM .0$ county road cnused by low bog �nd will continue to filling on top of thc � road embankment, settle, nggravating fiooding present road embankm�nt. problem. Also stabilize embankment. 11 0300 �4 Geology Extensive channel And Problems will continue. Provide adequate R/D in . RM .00-.40 bank erosion •and numerous uplands. (See Project landslides due co 3119.) . deve(opment-related stormwater. i 12 0300 ... 4 Hydrology 3119 Development-related peAk Increased erosion on Construct detention dam in I flows have caused sig- hilislopes below. deep, channelized reach of nificant bank erosion. . Trib. 0300. 13 0300 4 Hydrology 3109 � Collection point 4 has DegradAtion of Trib. 0300. Construct berm and standard RM 1.40 ' ' been neariy completety from RM .42 downstream. This control structure at outiet • . urbanized. section is very�ateep and to WetlAnd 3120 in Cascade susceptible to erosion. Park. 14 0302 6 Geology Channel dvwnc�itting and Will continue at same tevel Control storm flows from RM .50 bank.erosion. or increasc. uplands. 15 0302 G Geology B�nk erosion (modium den- Increasing erosion with Provide adequate R/D in RM .30-1.00 . sity� at meanders and increasing flow from devet- uplands as area develops. � - obstructions. . opments. P: LC.APC , C-3 � Trib. c�c Collect. Existin Antici t�ted E P Item River Mile Point Cate�ory Prop. Proi. Conditions and Problems Conditions flnd Problems Recommend�tions 1G 0302 G Geolo�y Gully erosion from broken None. Cu�vert h�s Ueen None. culverts. repaired, I 17 0302 6 Geology Severe gully erosion Continued erosion. Tightline flows to ' RM .60-.40 ereating small v�ileys mAin stem. from daylight culverts. 13 0�02 6 Habit�t Stream channeled �long While fish now use this Add h�bitat diversity RM.35 golf course roAd. No reAch, Inck of habitat will (e,g., structures, overhead overhead cover. No hnbi- eventunlly reducc popula- vegetation). Gain ' tnt diversity. tions, easement to restore mean- ', ders, if possible. 19 0302 6 Hydrology TributAry drnins down Problem will worsen as Construct detention dam RM .4,5 steep bluffs on north • devclopment upstream upstream of golf course, side of Cednr River, continues, carrying debris and � � flooding M�plewood Golf Course. 20 0302 6 HAbitat Wuter supply dam. Fuil As impoundment fills, storm- Dredge pond und m�intain RM .50 bnrier to upstrenm water will flood over bank. it as sediment catch. migration. Impoundmcnt Stnicture mny f�il. is filling with sediment. Z1 0302 6 HAbitnt � Severe.gullying from right Will continue to erode until - Tightline downslope. RM .90 bnnk corregnted metAl � reaches till layer. - Add velocity attenuAtor at pipe. Henvy sediment , stream. delivery to stre�m. P: LC,nPC C-4 (,. ,. ' -------- ---- � Trib. �. Coilect. ' Existing Anticipated , Item River Mile Point C�tc�orv Prop. Proi. Conditions nnd Problems Conditions �nd Problems Recommendations 22 0302 6 Habitat �Trpsh in strenm (Auto, Area �djacent to conidor, - Remove trash. RM 1.00 tires, nppliances). will continuc to collect - Distribute educational tr<ish und debris. Further materials to streamside � worsening of wAter quAlity, residents. sedimentntion, erosion. • Cite violators, if problem persists. 23 0302 6 Habitat Trash in strct►m. Water Area �djnccnt to corridor, - Remove trash. RM 1.10 qu�lity problem, will continue to collect - Distribute educAtional unsightly. trash nnd debris. Further materials to streamside worsening of water quality. residents. - Cite violators, if problem persists. 34 0303 6 � Geology Extensive bnnk erosion in Nonc. Increase R/D volumes, slow relcasc; upper portions of tribu- rate to nonerosive levels. tary. 25 0303 6 Hnbitnt H�bitnt suituble for resi- Sediments will eventullly - Control stormwater volumes RM .2S dent fish. Sediment nccu- cover grnycl.�. E{�bitat and discharge rates from � mutatins. will bccomc unsuitable for dcvelopmcnts. fish use. - Mam�ally cle�n grnvels when nece.ss.�ry. 2b 0303 6 H�bitat Trash and litter in Further decre�ses in water - Remove trash and littcr. RM .35 ch�nnel affecting water quality. - Distribute educational materials qua(ity,.causing erosion. to streamside residents. - Cite violators, if problem persists. P: 1.C.APC •G$ � Trib. Rc Collect. Existing Anticipnted Item River Mile Aoint Cnte�orv Pro�. Proi. Conditions nnd Problcros Conditions nnd Problems Recommend�tions � 27 0:�04 7, H�bitat Lt�ndslides contributing Sediment will continue to Maintain riparian corridor RM .40 sediment to chunnel. Hcavy enter system until landslide with setbacks at Ie�st 50' deposition in pool.s, nt stabilizes. from tops of banks. obatructions, even in . riffles. 2�4 0304 8 Hubitat Horses h�ve �cccs.s to Further decreases in water - Encourage residents to fencc RM 2.10 stre�m, e�using some b�nk quality, b�nk erosion likely. ch�nnel back 15' from ordin�ry deteriorntion and possibly h;gh-water mark. affeeting wnter c�u�lity, • Limit access to livestock to one or two points along strelm. 29 0304 8 Hydrology Flooding caused by fniling Problem will continue until - Problem referred to Mnin- RM ?.30 R/D at 17Gth St, fi 146t1t outlet structure is tenpnce section of Surfa�� Ave SE. modificd. Wuter Management Division. 30 0304 3 H�ibitat Encroachment occurring Wetlnnd likety to be - Require encroaching fills RM 2.40 along all boundaries of reduced slowly until it is to be removed. this headw�ter wetl�nd. completely d�stroyed. L.oss - Establish specific buffer of storlge, filtration, �round this wetland. or�anic production, and - Enforce sensitive areas . wildlife habitat. ordinnnces And re�n�la- tions. 31 0304 7 Gcology Severa) guUies due to Problem will continue. - Tightline drainage. RM .80 d�ylight culvcRs; A few hnve recent I�ndslides, P: LGAPC C-6 -' � � � . .. I Trib. �cc Collect. ' Existing ' Anticipated ' ' Item River Mile Point Cnte�orv Prop. Pro't. Conditions and Prol�lems Conditions �nd Probiems Recommendations 32 0304 7 H�Uit�t Extensive riffla (to RM Gr�vels risk becoming - Enhance habitat by addi- RM .00 .15. Creek ch�nneled. No cemented. Few resting arcas tion of woody debris in woody debris, little bank for upstroam migrating fish. stream. . vegctation. Steelhend, - Revegetate bank. cvho spnwncrs here. - Cnh�nce poot/riffle ratio. 33 0304 7 H�Uit�t Debris jam may be �► Debris will continue to - Selectively remove debris RM .20 , p�rtial migrntion b�rrier. �ccumulnte. Ch�nnei wilt to allow fish pas.s��ge. ' likely divert or jAm wiil - Stabilize large woody . fuil, rclensing accumulated debris. sediment. • 34 0304 7 HAbit�t � Debris js�m. Bed drops 3' Debris wili continue to - Selectively remove debris RM .h2 over jam and sediment, Accumul�te. Channel wilt to allow fish passage. forming anudromous likely divert or jam will - Stabllize large woocfy barrier. � Eail, relensing uccumulated debris. , sediment. • 3G 0304 7 Nabitat Wnter turbid; oily sheen W�ter quulity will continue - Educate residents about RM .80 nnd odor present. Storm to deeline ns runoff and how to muintain water c�uality. dr�ins empty directly into waste enter strenm. • Mark storm drains with strcAm. "Dump no oil" signs. • • Emph�sizc recycling of oil. 37 0304A 7 Iiydrology 3102 Existing forested wetl�nd Additional stonge coutd bc Construct a proportional weir RM 1.30 provides detention for utilized Uy constructing and berm at wetland outlet. Trib. 0304A and 0304 in berm and weir at outiet. Project could be used inste�d heAvily developed Area�. This could be done to atten- of Project 3107 to rpeserve the unte incrensed peak flows #1 rated wetland (where project ns upstre�m �re1 develops. would be built). P: LC.APC C•7 � � Trib. �c Collect. Existing Anticip�tted item River Mile Point C�te�orv Prop, Proi. Conditions �nd �roblems Conditions nnd Problems Recommendations 33 0304A 13 �•Iydrology 3115 Runoff generated on top of Flooding will continue as - Constn,ct detention pond RM .40 bluffs on southwest sidc long ns Innd use remains thc at top of bluffs. of Cedar River is enusing same on top of bluffs or - Tightline drainage down severe b�nk erosion, until mitigating measures bluffs, then channelize it flooding nnd debris flows are t�ken. Runoff origin- to nn existing ditch onto several residences ates from highly comp�cted alon�.side SR 169, of vAlley [loor. pasturelnnd on upinncls. - Prevent similar problems elsewhere with land use regulutions, including � � provisions for preservation . of veget�tion buffers neAr tops of cliEfs. 39 0305 10 Geolo�y Factensive bnnk erosion, Susceptible to increases Attenuate high [lows. pArtly due to subsur[ace with incres�sing storm flow. clay Iayer and I�ndslide topogrnphy. 40 030.5 10 Geology Local severe bAnk Problem will continue. Existing rock-filled RM 1.10 erosion. � �abions are deflecting ' flow. 4] 0305 10 Gcology Extcnsive chnnnel down- Continued erosion. Attcnuate high flows with RM 2.10• ' � cutting und bnnk crosion. adequate R/D. (R/D 1.75 � curnntly exists.) 4? 0305 10 Geology Severnl gullies and �sso- Lrosion will continue. Tightline culverts. RM 2.15- cinted landslides due to 1.'75 dnylight culverts on steep . slopes adjAcent to chnn- nc(s. P: LC.APC C•8 � ' — -------- - --- � Tril�. & Collcct. Existing . Anticipated Itcm River Milc Point C:ate�arv Prop. Proi. Conditions nnd Problems Conditions nnd Problcros Recommendations 43 0305 1Q I�I�bit�t Madsen Creek in ditcl� Along Potenti�l for fuel entry in- Acquire 30' easement �way RM .20 SE Jones Rd. Heavy silt; to creek. I'urther decrc:ases from roadside. Construct . road runofE; water quAlity in water quality can be ex- new stream channel. adversely affected, pected. 44 0305 10 I-IaUitat Creek in ditch nlong south Furthcr decreases in water Acquire 30' eusement away RM .35 � sidc of SR 169. HeAvy quality cnn be expected. from roudsidc. Construct inputs of oils, nnti- Potenti�►I for autos to enter new stream channel. ' freezes, heuvy metnls, channel. L,.�ck of h�bitat. . organic pollutnnts likely. S�nd, silt from rondside (of SR,169) entcrs Also. 4S 0305 ItM .00- 10 Fiydrology 3105 Scction of Trib. 0305, Plooding will continue. Construct �nd enhance 2200' of .40 RM .00-.40 is experiencing (See Appcndix A, Projeet channet through undeveloped . � extCnsive floociing. 3105.) King County Park Land. 46 O:�OS 10 Hnbit�t Chnnnelized s�long dri- rurthtr silt�tion, water ACquire easement; move RM .50 veway; Incks hnbit�t qunlity dcgradation can be creek from driveway diversity. Driveway sedi- anticipated. Lack of habitat 10-15'. Add meanders and ments enter chnnnel, nnd preciudes optimum salmonid habitat structures to oi� placed on driveway use, increase diversity. enters strenm. 47 0305 10 I-Inbitat Ch�nnclized tributnry Little s��lmonid usc Add structures to incrensc RM .65 l�cks hnbit�t diversity, �ntieip�ted. Splwning nnd diversity in stream. cover for snlmonids. rearing succes.s limited Manually clean gravets by Gravels compacted. (unles.5 rench is restored). churning them. P: LC.APC C-9 � Trib. Rc Collect. Existing Anticipatcd Item Rivcr Mile Point C�te�orv Prop. ProL Gonditions and Problems Conditions �nd Problems Recommend�tions 4g 0305 10 �-I�bitflt C3ood spflwning riffies occur Incrensed flows may cause Control flows into system RM .90 hare. �/i-3" grnvels, fcw gravcl bnr movcment. from developed �►rens fines, not compnct. High Suitflble grnvets m�y be upstream. If ncces.s��ry, flow� fln moving mnteri�l, transported downstream to add bed controls to hold however. unus�ble s�reas [or sp�wning �ravels or "vee" struc- s��lmonids, tures to recruit them. 49 0305 10 H�bit�t Severe b�►nk cutting nnd Further erosion/scouring c�n Control high flows by RM .95 erosion occurs here. Bcd be cxpected. Chflnnel increasing upper basin R/D scouring evident. Reach deterioration will continue. facilities, lowering suUject to high, rflpid Flows �ppe�r to Ue gener�ted discharge rates to stream. flows, at developments. 50 0305 10 Habitat Mueh woody debris Debris jums will occur with Control upstream flows RM 1.20 movement nnd numerous greater [requency ns [lows with grc�ter R/D volume, dcbria jnms. Reach is incrcnse. Sediments will lower dischArge rates. subject to high, rapid build up 1nd channel will Scicctively remove dcbris. flows. divert. ,S� 030.5 10 N�bit�t Ch�nnel erosion, bank Further channel deteriora- - Increase R/D capacity. RM 1.70 f�iluros, downcutting oc- tion may be expected. Silt, - Decre�se discharge rates. curring. Renclt subJect to sAnd tr�nsport to m�instem high, r�pid flowg, will incrc�se, 52 0306 10 Geolo�y Fnilure of manhole during Not �pplicnhle. Rep�ir manhole. RM .40 11/86 storm hns resultcd in ' gully erosion. P: LC.APC C•10 f - __ ---- _ ---- � Trih. �C Colicct. Existing Anticiplted Item River Mile Point Cate�ocY Prot�, Pro't. Conditions �nd Pmblems C'onditions �nd Problems Recommendations S3 0306 10 Geology Ch�nnel downcutting, b�nk �rosion will inerease. G1�y Further increase in runoff �i RM ,20 erosion and severnl I�yer in vllley mnkes area should be lttenuated; this I ' I�ndslides, due both from sensitive to landslides. is a sensitive channel. ' • increased storm flows and ' , development along edge. 54 0306 10 Geotogy Undersized culvert in arti- Possible fill failure: Lake Enlarge the corregated RM .30 ficial fill in golf course ponded behind culvert in metal pipe and/or � threatens to Uuild I�ke and in 1981 �nd tltreatened construct adequate txash possibly overtop bank. the fi1t. rack. Brcach .flood possibl�. 55 030G 11 I•I�bitat � ChAnnel subject to hi�h, I'urther ch�nnel d�mage c�n Increase R/D capacity, RM .?5 damflging flows. Erosion be expectcd. Scdiment decrease discharge rate. evident, transport downstream will continue. SG 030( 10 Gcology Downcutting, bnnk erosion Will continue or increase in Attenuate storm flows. RM .30-.45 �nd landslides. futuro. 57 03QG I-Iydrology 3118 Trih. 03Qb conncets with Problem will worsen as - Replace existing pipes RM .30 large tributAry t►t manhole devolopment upstrenm with I�rger diamcter pipes herc. �DcUris from 0306 continucs. (if downstrcam anatysis clo�.s this mnnholc, c�using nllows for incre�sed flows). severe erosion of F�iiwood - Inst�ll new inlet struc- Golf Cout�e, tures with trash racks. 53 030GA 11 f-Iydrology 3122 Existing small ponds on Are� upstrenm is developing - Acquire easements for ponds RM 1.30 0306A nre overtopped and quickly, thus worsening the and Additional area around ponds � receive considerable silt problem. and construct detention pond, during high flows. Tlte - Location is ideal [or addressomg ' ponds are located on peak flows before they rench rlirwood Golf Course, the sensitive Cedar Reiver bluffs. P: LC.APC C-11 � . • I� I II Trib. �C Collect. Existing Anticipated Item River Mile Point Cate�orv Prop. Proj. Conditions �tnd Problems Conditions and Problems Recommendations 59 030fiA 11 1-I�bit<tt Some usable habitat exists Further haUitAt deterioration - Increase R/D capacities. � RM .25 for resident s��lmonids. likety. Clinnnel erosion will - Decrease discharge rates. , Water quality is poor. increase. - Encourage use of 2-cell Chann�l subject to high detention ponds, swales. � flows. � - Prohibit filling of • existing wetlands, ponds �, in upper basin. GO 0307 12 Geology Extensive bs�nk erosion nt Increflsed erosion will - Mitigate development- RM .10-.40 all meanders and obstruc- result with increased flows. related high flows. I tions (trees, ct�rs) due - Provide adequate R/D. I to increlsed flows from development. 61 0307 12 Geology Stream eroding toes of Increasing erosion with - Mitig�te development RM .10-.GO alopes resultin� in increasing [lows. related high flows. landslide f�ilures. - Provide adequate R/D. <2 0307 12 I•I�bit�t Stream ehannel pushed to Erosion will worsen as - Incrcase R/D capacity nt RM .30 one side of ravine for stream flows increase. all delivery points. � roAdway. High encrgy May thre�ten road barrk at - Reduce release rate below system. Much bnnk cuttin�, toe of slopc. ch�nncl scour lcvel. scdimcnt trans�ort, dc;bris movement. 63 0307 13 Hydrology Aren on top of hluffs ne�r Infiltr�tion sites should Constroct retention faci- RM .GO Trib. 0307 hAs excellent be used wlunever possible. lities for new develop- in[iltrative capueity. These would provide ground- ments in area at these sites. wAter rech�rge. r: �c.Arc c•i2 � — � Trib. �C Colicct. Existing Anticipated Item River Milc Point Cntc�orv Prop. Proj, COnditions and Problcros Conditions �nd Problems Recommend�tions (4 0309 15 H1bit�t Subject to he�vy, rnpid Erosion, de�osition will - Control storm fiows �� RM .10 flows. Channel erosion, incrG�se. Scdiments will upstream. • deposition bars migration, migrate downstream, creating • Control volume and discharge a wnter quality problem. rates. GS 03]0 15 Gcology Sedimentation upstre�m from Continued sedimentation. - See "Hydrologic and hydraulic RM .60 culvert due to deUris and characteristics" section in �� undersized culvert. New this report. I corregnted mct�l pipe con- tinues to pass wnter througl�. GG 0310 15 Gcology Sever� erosion below Continued erosion and - Install energy dissipator RM .OS culvcrt, severe sedimcn• scdimcntntion. below corregated metal pipc. tution in resid�nce y�rd, - Excavate channcl through y�rd where original channel was IocAted. 67 0310 15 Geolo�y Rond drAinage forming gully Continued erosion. Reroute drainage. Refer problem RM 1..50 ndjAcent to roud; rond bed to Roads Maintenancc. in danser. �4 0310 1S I•I�bitat 3120 Corng�ted mett�l pipe is Probl�m wil! continue. Reinstpll corregated metal RM .25 nnndromous b�rricr. pipe ut or below bed level. P: I.C.APC C-13 Tril�. �C Collect. �xisting � Anticipnted ltem Rivcr Mile Point C�t� Prop. Proi. Conditions And Prohlems Conditions �nd Problems Recommendations 69 0310 15 Hydrology 3120 �xisting clinnnel dr�ining Frequency �nd severity of Construct detention pond RM .40 of[ blu(fs on north side problem will worsen �s on upstream side of Jones of CedAr River, causing development on bluffs Rd. to trap sedimcnts, and [looding of residences und increases. enhance 1,000' of creek debris flows onto Jones Rd. from Jones Rd. to Cedar during penk flows. River. 70 0310 15 H�Uit�t Corngated metal pipe Problems will continue and Removc new and o1d pipes; ' RM .60 outlet approxim�tely worsen as outfall velocities replace at Iower level � 9' above bcd Ievcl. will scour bed nnd bunks. with oversized pipe with Complete bnrrier to fish. Upstrerm h�s ncent (11/36) trnsh rack. Old •culverts At bcd Icvcl deposition up to 4' deep. are plugged. 71 0311 13 Geolo�y C3ully erosion in dr�innge Continued nccelerated ero• If possible, enlarge R/D RM 1.70 sw�le due to outflow of sion. prior to its outlet in the wetland that partly seems wetland. � to �ct as an R/D facility. 72 0314A 16 Hy.drolofiy 3117 Severe erosion, floodin�, Problem will Ue a�ravated - Tightline drainage between RM .20 dAmagc to County nnd as nre� nUove dcvelops. detention ponds in gravel pit. priv�te ro�da from � . - Construct detention pond increased runoff from next to Jones Rd. to tr�p . grnvel pit opentions on sediments. hillside: - Constn�ct channel from Jones Rd, to CodAr River. 73 0314A/ 16 Gcology Inadequatc R/D, plugged Not applicflUle. Sce hydrology comment 0314I3 culvert caused by exten- above. RM .10-.40 sive channel and b�nk erosion nnd Inndslides. � � W�ter hns cut � new chnnnel. :, P: LC.APC C-14 �• • , � Trib. �C Collect. Existing Anticipnted Item Rivcr Mile Point Cnte�ory Prop. Proj. Conditions �nd Problems Conditions and Problera�s Recommendations 74 0317 Hydrology 3111 Fnncis I.�k� is only Trib. 0317 [lows through - Construct proportion�l RM 1.�0 hydri�ulic nontrol for steep nre� downstreAm of weir at outlet. Trib. 0317. I�ke. If �rea nround Francis • Enhance 1,100' from L,��ke develops, increased Francis Lake to SE 134th St. pcak flows could c�use severe d�m�gc to Trib. 0317 in the ', steep re�ion. ' 75 0320 Hydrology 3114 E�;isting forested wetland if surrounding Are� urb�n- Constnict containment berm RM 2.40 with lacge �mount of un• izes, this would be a good and control stn,cturc at utilized stornge. Wctl�nd site to �ttenuate peak outlet of wetland (if bio- currently d�tAins [Iows on flows. logicul an�lysis permits). Trib. 0320. 7G 0313 19 I��bitnt Snlmonld parr in many DCCrCASC in w�tcr quAlity Fstablish and maintain RM .10 pools. Lurge pools up to with increasing develop- adequ�te buffers, 100' � 1.75' deep. Some deposi- ment. L,oss o[ habitat. from ordinary high-water tion in pools, bchind DecreAse in [ish use. mnrk or 25' from top fo obstructions. . slope break, whichever is greater. 77 0342 19 H�bitut Salmonid use app�rent from System is mostly in nnturnl - Maint�in adequate stream RM .3S eflrcnsses. Sockeye, condition. As development corridor buffers. Chinook ap�wncrs. Some increnses, higher flows and - Reducc discharge r�tes to sedimentation occurring. worse water quality can be pre-devclopment levels. . expected. Prcvent clearing, gr�ding within buffers. P: LC.APC G15 _ ___ Trib. �cc C:ollect. E�;isting Anticip�ted , Itcin River Milc Point C�te�orv Pror. Proi. Conditions �nd Problems Conditions and Probiems Recommendations ' 74 Q32g 19 Geolagy Medium-density Inndslides I�1one. Limit development in tite RM .SO und high-density bink � basin. crosion occurring duc to natural c�uses. This indi- cates ch�nnel and valley sensitive to effccts of - development. (Sensitivity due , to clny layer. Basin hnsts somo o[ bast fish habit�t I in upper rcaches.) 79 03?3 19 I-I�l�itnt 5ignifieant snlmonid usc Sedimentntion from upstream Maintain leave strips RM .70 throughout. Sockeye reAch possible. Adj�cent adjaccnt to stream at �pnwners, cnrcnsaes prosent. development will likely least 100' from orciinnry Coho, st�elhend pnrr in reduco diversity and c�u�lity high-water mark. Restrict pools. Exccllent habitat of habit�t. usc/development within this for spuwning nnd re�ring streAmside mun�gcment zone. (a redd site). Muclt diversity -- most eaemplary in bAsin. Ch�nnelized reach. Uniform May c�use therm�l problems Restore stream habitat 80 0324 19 H�bitat ch�nnel, no h�bitnt diver- ns water temperntures rise. throughout: add structure, RM 1.10 sity. Heavy s��nd deposition. No useful habit�t. diversity, Uank vegetation, ].40 1..ittle overhe�d c�nopy or and clnopy. Cost should be bank vegctation. borne by party(ies) who ch�nnelized this ro�ch. 31 03?3 19 �Iydrology 3112 Lake Peterson is smnll, L,�ke provides good penk flow Replace weir at outlet RM 1.40 open w�tter wetl�ncf with n uttenus�tion nnd will Uecome with a higher weir in wcir �t outict. more import�nt �s upstream order to gain additional tril�utnry �ren develops. stor�ge. P: LC.APC C•lb .. ,. �� — --- ,. . . - - - - -- - r _ - i {_ ; • j � , III I __ . � ' � i �� il ' - �� I � III '_ SECTION 4 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN � I � I � 1 __ _ _ _ __ _ I �� 1 c��-, LZ BAIMA & HOLMBERG, INC. 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' :_ __ _ __ _ _ _ : ._ : . _ : :. _ :. .. , : . ;_. __ ' ; _ _ _ ... _ _ I :. �� ,r '' ..... ' :.. _.. _ 'I : g c�� ...: o�� .__.. _._ .. � : .__ . _ _ _ _.. .. _ ;. _ :_ �'t►'zL w► � _ _ _._ :_. . . . _ . _ . . _�+�t- o ti0 �. _ _ : _ ; .;_ _ � _ � . _ _ _ �7� _ , __�_..,��__. .��__ DESIGN POND VOLUME Detention Volume Stage Area Inc. Volume Volume (ft) (s� (c� (c� Total Detention Volume = 31841 cf 403 12948 12159 31841 402 11369 10624 19682 401 9879 9d58 9058 400 8237 0 Water Quality Volume (Cell 1) Stage Area Inc. Volume Volume (ft) (s� (c� (c� W/Q Volume = 5945 cf 400 3348 5278 5945 398 1930 667 fi67 396 739 Q 0 Water Quality Volume (Cell 2) Stage Area Inc. Volume Volume (ft) (s� (cf} (c� W/Q Volume = 8975 cf 400 4319 5435 89i� 398.5 2927 3541 3541 397 1794 Q 0 Total W/Q Volume = 14921 cf ' Existing Conditions RCRTS Peaks Flow Frequency Analysis Time Series File: 1004u.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.158 2 2/09/Ol 18:00 0.208 1 100.00 0.990 0.049 7 1/06/02 3:00 0.158 2 25.00 0.96C 0.120 4 2/28/03 3:00 0.122 3-' 10.00 0.900 0.005 8 3/24/04 19:00 0.120 4 5.00 0.800 0.071 6 1/OS/05 8:00 0.106 5 3.00 0.667 0.122 3 1/18/06 21:00 0.071- 6 ---- 2.00 0.500 0.106 5 11/24/06 4:00 0.044 7 1.30 0.231 0.208 1 1/09/08 9:00 0.005 8 1.10 0.091 Computed Peaks 0. 191 50.00 0.980 Developed Conditions KCRTS Peaks Flow Frequency Analysis Time Series File:1004d.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.435 5 2/09/O1 2:00 0.896 1 100.00 0.990 0.340 8 1/05102 16:00 0.526 2 25.00 0.960 0.526 2 2/27/03 7:00 0.509 - 3 10.00 0.900 0.351 7 8/26/04 2:00 0.460 4 5.00 0.800 0.427 6 10/28/04 16:00 0.435 5 3.00 0.667 0.460 4 1/18/06 16:00 0.427------ 6 2.00 0.500 0.509 3 10/26/06 0:00 0.351 7 1.30 0.231 0.896 1 1/09/08 6:00 0.340 8 1.10 0.091 Computed Peaks 0.773 50.00 0.980 ' 3' Deep RCRTS Level 2 Detention Pond Retention/Detention Facility Type of Facility: Detention Pond , Side Slope: 3.00 H:lV Pond Bottom Length: 167.00 ft -- Pond Bottom Width: 50.00 ft - Pond Bottom Area: 8350. sq. ft Top Area at 1 ft. FB: 14134. sq. ft 0.324 acres Effective Storage Depth: 3.00 ft Stage 0 Elevation: 0.00 ft Storage Volume: 31233. cu. ft 0.717 ac-ft Riser Head: 3.00 ft Riser Diameter: 12.00 inches Number of orifices: 2 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS} (in) 1 0.00 0.88 0.036 2 2.10 1.94 0.097 4.0 Top Notch Weir: None Outflow Rating Curve: None Stage Elevation Storage Discharge Percolation Surf Area (ft) (ft) (cu. ft) (ac-ft) {cfs) (cfs) (sq. ft) 0.00 0.00 0. 0.000 0.000 0.00 8350. 0.01 0.01 84. 0.002 0.002 0.00 8363. 0.02 0.02 167. 0.004 0.003 0.00 8376. 0.03 0.03 251. 0.006 0.003 0.00 8389. 0.04 0.04 335. 0.008 0.004 0.00 8402. 0.05 0.05 419. 0.010 0.005 0.00 8415. 0.06 0.06 503. 0.012 0.005 0.00 8428. 0.07 0.07 588. 0.013 0.006 0.00 8441. 0.17 0.17 1438. 0.033 0.009 0.00 8572. 0.27 0.27 2302. 0.053 0.011 0.00 8704 . 0.37 0.37 3179. 0.073 0.013 0.00 8837. 0.47 0.47 4070. 0.093 0.014 0.00 8970. 0.57 0.57 4973. 0.114 0.016 0.00 9104 . 0.67 0.67 5890. 0.135 0.017 0.00 9239. 0.77 0.77 6821. 0.157 0.018 0.00 9374 . 0.87 0.87 7765. 0.178 0.019 0.00 9510. 0.97 0.97 8723. 0.200 0.020 0.00 9697 . 1.07 1.07 9695. 0.223 0.022 0.00 9784. ' 1.17 1.17 10680. 0.295 0.022 0.00 9923. 1.27 1.27 11679. 0.268 0.023 0.00 10062. 1.37 1.37 12692. 0.291 0.024 0.00 10201. 1.47 1.47 13719. 0.315 0.025 0.00 10342. 1.57 1.57 14761. 0.339 0.026 0.00 10483. 1.67 1.67 15816. 0.363 0.027 0.00 10625. 1.77 1.77 16886. 0.388 0.028 0.00 10767. ' , 1.87 1.87 17969. 0.413 0.028 0.00 10911. 1.97 1.97 19068. 0.438 0.029 0.00 11055. 2.07 2.07 20180. 0.463 0.030 0.00 11199. 2.10 2.10 20517. 0.471 0.030 0.00 11243. 2.12 2.12 20742. 0.476 0.031 - 0.00 11272. 2.14 2.14 20968. 0.481 0.033 0.00 11301. 2.16 2.16 21194. 0.487 0.037 0.00 11330. 2.18 2.18 21421. 0.992 0.043 0.00 11359. 2.20 2.20 21649. 0.997 0.050 0.00 11389. 2.22 2.22 21877. 0.502 0.058 0.00 11418. 2.24 2.24 22105. 0.507 0.067 0.00 11947. 2.26 2.26 22335. 0.513 0.072 0.00 11476. 2.36 2.36 23490. 0.539 0.084 0.00 11623. 2.46 2.46 24659. 0.566 0.094 0.00 11771. 2.56 2.56 25844. 0.593 0.102 0.00 11919. 2.66 2.66 27043. 0.621 0.110 0.00 12068. 2.76 2.76 28257. 0.699 0.117 0.00 12218. 2.86 2.86 29487. 0.677 0.124 0.00 12368. 2.96 2.96 30731. 0.705 0.130 0.00 12519. 3.00 3�40 31233. 0.717 0.133 0.00 12580. 3.10 3.10 32499. 0.746 0.446 0.00 12732.^ 3.20 3.20 33779. 0.775 1.020 0.00 12885. 3.30 3.30 35076. 0.805 1.750 0.00 13039. 3.40 3.40 36387. 0.835 2.550 0.00 13193. 3.50 3.50 37714. 0.866 2.830 0.00 13348. 3.60 3.60 39057. 0.897 3.090 0.00 13504. 3.70 3.70 40415. 0.928 3.330 0.00 13660. 3.80 3.80 41789. 0.959 3.560 0.00 13817. 3.90 3.90 43179. 0.991 3.770 0.00 13975. 4.00 4.00 44584. 1.024 3.960 0.00 14134. 4.10 4.10 46005. 1.056 4.150 0.00 14293. 4 .20 4.20 97443. 1.089 4.330 0.00 14453. 4.30 4.30 98896. 1.122 4.510 0.00 14619 . � 4.40 4.40 50366. 1.156 4.670 0.00 14776. 4.50 4.50 51851. 1.190 4.830 0.00 14938. 4.60 9.60 53353. 1.225 4.990 0.00 15101. 4.70 4.70 54871. 1.260 5.140 0.00 15265. 4.80 4.80 56906. 1.295 5.290 0.00 15429. 4.90 4.90 57957. 1.331 5.930 0.00 15594. 5.00 5.00 59525. 1.367 5.570 0.00 15760. Hyd Inflow Outflow Peak Storage Target Calc Stage Elev {Cu-Ft) (Ac-Ft) 1 0.90 ******* 0.30 3.05 3.05 31914. 0.733 2 0.43 ******* 0.13 2.90 2.90 30013. 0.689 3 0.53 0.12 0.11✓ 2.73 2.73 27886. 0.640 10-yr 4 0.43 ******* 0.10 2.53 2.53 25991. 0.585 5 0.46 ******* 0.05 2.20 2.20 21633. 0.497 6 0.27 0.07 0.03� 2.08 2.08 20245. 0.465 2-yr 7 0.34 ******* 0.03 2.00 2.00 19402. 0.445 8 0.35 ******* 0.02 1.12 1.12 10195. 0.234 ---------------------------------- Route Time Series through Facility Inflow Time Series File: 1004d.tsf Outflow Time Series File:rdout Inflow/Outflow Analysis Peak Inflow Discharge: 0.896 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.301 CFS at 10:00 on Jan 9 in Year 8 Peak Reservoir Stage: 3.05 Ft Peak Reservoir Elev: 3.05 Ft Peak Reservoir Storage: 31914. Cu-Ft . 0.733 Ac-Ft Flow Frequency Analysis Time Series File:rdout.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) (ft) Period 0.160 2 2/09/O1 20:00 0.301 3.05 1 100.00 0.990 0.030 7 1/07/02 5:00 0.160 3.01 2 25.00 0.960 0.115 3 3/06/03 22:00 0.115 2.73 3 10.00 0.900 0.022 8 8/26/04 8:00 0.100 2.53 4 5.00 0.800 0.030 6 1/08/05 6:00 0.050 2.20 5 3.00 0.667 0.050 5 1/19/06 12:00 0.030 2.08 6 2.00 0.500 0.100 4 11/24/06 9:00 0.030 2.03 7 1.30 0.231 0.301 1 1/09/08 10:00 0.022 1.12 8 1.10 0.091 Computed Peaks 0.254 3.04 50.00 0.980 Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence Probability CFS $ $ % 0.002 29875 48.720 48.720 51.280 0.513E+00 0.007 7779 12.686 61.406 38.594 0.386E+00 0.011 6914 11.275 72.681 27.319 0.273E+00 0.016 6264 10.215 82.896 17.104 0.171E+00 0.020 4902 7.994 90.890 9.110 0.911E-01 0.025 2677 4.366 95.256 4.744 0.474E-01 0.029 2023 3.299 98.555 1.445 0.144E-01 0.034 469 0.757 99.312 0.688 0.688E-02 0.038 58 0.095 99.406 0.594 0.594E-02 0.043 30 0.049 99.455 0.545 0.545E-02 0.047 34 0.055 99.511 0.489 0.489E-02 0.051 39 0.064 99.574 0.426 0.426E-02 0.056 18 0.029 99.604 0.396 0.396E-02 0.060 21 0.034 99.638 0.362 0.362E-02 0.065 12 0.020 99.658 0.342 0.342E-02 0.069 20 0.033 99.690 0.310 0.310E-02 0.074 24 0.039 99.729 0.271 0.271E-02 0.078 22 0.036 99.765 0.235 0.235E-02 0.083 19 0.031 99.796 0.204 0.204E-02 0.087 9 0.015 99.811 0.189 0.189E-G_ 0.092 13 0.021 99.832 0.168 0.168E-0: 0.096 13 0.021 99.853 0.147 0.147E-C: 0.101 21 0.034 99.887 0.113 0.113E-0� 0.105 10 0.016 99.904 0.096 0.962E-03 0.110 10 0.016 99.920 0.080 0.799E-03 0.114 10 0.016 99.936 0.069 0.636E-0�? 0.118 10 0.016 99.953 0.047 0.473E-0: 0.123 12 0.020 99.972 0.028 0.277E-0 , �-, , , , ��, �:� , �, �, _ , � �� _ ' 0.132 6 0.010 99.992 0.008 0.815E-09 0.136 3 0.005 99.997 0.003 0.326E-04 0.141 0 0.000 99.997 0.003 0.326E-04 0.145 0 0.000 99.997 0.003 0.326E-04 0.150 0 0.000 99.997 0.003 0.326E-04 0.154 1 0.002 99.998 0.002 0.163E-04 0.159 0 0.000 99.998 0.002 0.163E-04 ' Duration Compariso Anaylsis Base File: 1004u.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS #NAME? of Time----- #NAME? of Tolerance------- Cutoff Base New °kChange Probability Base New %Change 0.036 � 8.90E-Q3 6.20E-03 -29.7 � 8.90E-03 0.036 Q.03 -16.3 4 0.041 � 7.10E-03 5.6dE-03 -21.4 � 7.10E-03 0.041 0.033 -20.5 0.046 � 6.00E-03 S.00E-03 -17.3 � 6.00E-03 0.046 0.037 -19.4 0.051 � 5.30E-03 4.30E-03 -18.9 � 5.30E-03 0.051 0.044 -14.6 0.056 � 4.60E-03 3.90E-03 -13.9 � 4.60E-03 0.056 0.049 -12.9 0.061 � 3.90E-Q3 3.60E-03 -9.9 � 3.90E-03 0.061 0.056 -8.2 0.066 � 3.40E-03 3.30E-03 -1 � 3.40E-03 0.066 0.066 -0.7 0.071 � 3.00E-03 3.00E-03 0 � 3.00E-03 0.071 0.071 0 � 0.076 � 2.60E-03 2.50E-03 -3.1 � 2.60E-03 0.076 0.075 -1.8 � 0.082 � 2.30E-03 2.10E-03 -6.4 � 2.30E-03 0.082 0.079 -2.7 � �� 0.087 � 1.90E-03 1.90E-03 0 � 1.90E-03 0.087 0.087 0.4 � d.092 � 1.SOE-03 1.70E-03 9.5 ( 1.SOE-03 0.092 0.095 3.4 0.097 � 1.30E-03 1.40E-03 12.8 � 1.30E-03 0.097 0.098 1.9 0.102 � 1.00E-03 1.10E-03 6.3 � 1.00E-03 0.102 0.103 1.9 0.1 d7 � 7.70E-04 9.00E-04 17 � 7.70E-04 0.107 0.111 4.1 0.112 � 5.90E-04 7.50E-04 27.8 � 5.90E-04 0.112 0.115 2.8 0.117 � 4.40E-04 5.40E-04 22.2 � 4.40E-04 0.117 0.119 2.4 0.122 � 3.30E-04 3.4QE-04 5 � 3.30E-Q4 0.122 0.122 0.3 0.127 � 2.60E-04 2.00E-04 -25 � 2.60E-04 0.127 0.124 -2.1 0.132 � 2.10E-04 9.80E-05 -53.8 � 2.10E-04 0.132 0.126 -4.2 0.137 � 1.60E-04 3.30E-05 -80 � 1.60E-04 0.137 0.129 -6 0.142 � 1.50E-04 3.30E-05 -77.8 � 1.50E-04 0.142 0.129 -9.1 Q.147 � 1.30E-04 3.30E-05 -75 � 1.30E-04 0.147 0.13 -11.5 0.152 � 6.50E-05 3.30E-OS -50 � 6.SOE-OS 0.152 0.132 -12.8 0.157 � 1.60E-05 1.60E-OS 0 � 1.60E-OS 0.157 0.16 1.8 Maximum positive excursion= 0.004 cfs (4.7°r6) occurring at 0.09 cfs on the Base Data:1004u.tsf I and at 0.095 cfs on the New Data:rdout.tsf Maximum negative excursion = 0.008 cts(-20.5%) occurring at 0.041 cfs on the Base Data:1004u.tsf and at 0.033 cfs on the New Data:rdout.tsf I � •. . . � .. ., : . _ � , _ _ ,� =L1 x! � -=�_�:_._. „ _ o �-�_ _ � --�� t=- -, ._,r ♦ i .� �'y - - I � o R � I — � N '1 r- o \� ,� +R. ^ O � � R , LL � � U �► � � �� : L O � U ; N O � � � � � � :i o � 0 ' oo �`� N O O O O 10 5 10 4 10 3 10 z 10 ' 10° Probability Exceedence �Jf2�-�n� �cJ Y1�i/�' � SECTION 5 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 1 __ � ,,oe —�DZL I'� BAIMA & HOLMBERG, INC. SHEETNO. OF I 100 Front Steet South ISSAQUAH, WASHINGTON 98027-3817 cr�cuuTeoev_T� DATE (425) 392-0250 FAX (425) 391-3055 CHECKED BY DATE SCALE _ CmnJ(/�-�J(�� S�S/�/I►� _._ : __ _ � �J�K�(Gwr4I�11. , 14-IlJ�4L ys l S ' _ _ _ . _ . . _ _ _ � : _ . _ 4 _ ... _�_._..._ } ; , :.__ ASSu w+� oN,p _ _ _ G�3 !D , _. _ _ _._. ..;_ tJIJ q.1�� 2'F.¢-ct� � _ oV . � --- .� : ,;._.: --- __ , _ ._. ._ 3�. o ! +�ca� __ G� �- . __ : _ __ _ : . _ , __ . �oN , : � __-- � __ _ � � G�� _: . . _._. : _ � '- ,.,,.• � ��3 6 �' : ; Z _ _: . . _ � _ _ _ � . _ : � ; --_ � _ ,_ __ ___ : _) . . : __ � _ _ 1 __ _ � . � _ . � 3 . - ._ - � � �. . _ _ � _ I _ . 5 _ ' _._ � — � . . . . . . ii . �. .... _. . . . _... . .. . . . . _..... .. , ... ..... ..... Q � Bk �6��s �s� s��. �� _ _ . , _ _ :. mo : :....._...:_ ..:_ s _ _ � _ _ _ _ -_--. :. . : �st�4 K� �w ' S,�-� �� . :-_ _ : . �o - l,Bw S1 � N __ �� `rs : : � ' � :. _ s�r� s�rs� : : _ l. __ _ .; . _ ' . _ _ .I : m�- _: : : . l e � 100-yr Backwater Analysis of Onsite Storm System PIPE NO. l: 35 LF - 12"CP @ � .57� OUTLET: 398.00 INLET: 398.20 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 404.00' BETtD: 85 DEG DIA/WIDTH: 4.0 Q-RATIO: . 00 �C.�3 Z Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ��******��**�*�********�+****��****�***********+*�*************�*********�* . 90 4.85 403.05 �*�/ .012 .40 . 39 5.00 5.00 4.82 4.85 .56 "��1`� PIPE NO. 2: 75 LF - 12"CP @ .51'� OUTLET: 398.20 INLET: 396.58 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 405.50 �BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: .00 Q(CFS) HW(FTj HW ELEV * N-FAC" � DN TW DO DE HWO HWI *******�*�*********��******�***+***+************��***********�**�*********�***� .90 4.56 403.14 /* .012 .40 .40 4.85 4.85 4.52 4.56 .56 -- at� PIPE NO. 3: 90 LF - 12"CP @ .50* OUTLET: 398.58 IPILET: 399.03 I21TYP: 5 NNC NO. 3: OVERFLOW-EL: 403.50�BEND: 85 DEG DIA/WIDTH: 2.0 Q-RATIO: .00 Q(CFS) HW(FT) HW ELEV N-F`C� �C DN TW DO DE HWO HWI *******�*�********�*********�********************************��*�**��*****�***� . 90 4.19 403.22 �* .012 .40 .40 4.56 4.56 4. 16 4.19 .56 �� i�+ PIPE NO. 4: 78 LF - 12"CP @ 4.87# OUTLET: 399. 03 IDILET: 402. 83 INTYP: 5 JUNC NO. 4: OVERFLOW-EL: 403.50� BEND: 40 DEG DIA/WIDTH: 2.0 Q-RATIO: .00 � �i Q(CFS) HW(FT} HW ELEV. * N-FAC D DN TW DO DE HWO HWI ' *�***�*�*�*�****�**�*�**��*�*�*�***��*�******�****�*****************�****��**** .90 .60 40`��* .012 .40 .22 4.19 4.19 .46 .60 .52 � PIPE NO. 5: 134 LF - 12"CP @ .50� OUTLET: 402. 83 INLET: 403.5U INTYP: 5 JUNC NO. 5: OVERELOW-EL: 406.00 BEND: 10 DEG DIA/V7IDTH: 2.0 Q-RATIO: . 00 � G : Q(CFS) I-IW(FT) HW ELEV. * N-FAC DC� DN T4V DO DE HWO HWI �*********�*******+****�*************�**��***�**************�****************�* .90 .60 404.10 m, .012 .40 .40 .60 .60 .40 .60 .54 ..�� I_ PIPE NO. 6: 150 LF - 12"CP @ .50$ OUTLET: 404.59 INLET: 405.34 INTYP: 5 ' JUNC N0. 6: OVERFLOW-EL: 406.44 BEND: 90 DEG DIA/WIDTH: 2.0 Q-RATIO: .00 ..�� ! Q(CFS) HW(FT) HW ELEV. * N-FAC D� �DN TW DO DE HWO HWI � ***�*�***�**�*********�****�*********************�****��********�*****�***�**�� .90 .62 405.96 * .012 .40 .40 .00 .40 .40 .62 .56 ✓� PIPE NO. 7: 32 LF - 12"CP @ .50$ OUTLET: 405.34 INLET: 405.50 INTYP: 5 Q(CFS} HW(FT) HW ELEV. * N-FAC DC G DN�TW DO DE HWO HWI ��I **<*�***�*�********�*************��*+��,.��+,.*+*.***��*��*��****�*********** .90 .61 406.11 * .012 .40 .40 .62 .62 .48 .61 .56 SECTION 6 SPECIAL REPORTS AND STUDIES 1 ' � F-� ' � � O � w U � � � H O SECTION 8 ESC ANALYSIS AND DESIGN _ � �os BAIMA & HOLMBERG, INC. SHEETNO. OF 100 Front Steet South ISSAQUAH, WASHINGTON 98027-3817 cucuu+�nev DATE (425) 392-0250 FAX (425) 391-3055 CHECKED BY DATE SCALE , _ _ _ : . . ��SG (��sl � __ _ rv ._ _ _. . _ : :... � _ -_ _ _.. __ _ ; ��ueC� �v r4-�� Z. Z 8�G : � __ _ _ _ _ � _�z = � � �fo �� . s��- s��ri � : : : v�✓ ; __ _ �'�-`�rD S��t+��N 7` ��'p' SU/2�/QG� . ._ ;. I ' ' _ __ _ _.._ .. . _ ��J�� s �� ,� �z _ : .: : _ _ ' _. . : . _....: _. . : _ -_ _ _ __ : . _ .._. .. i . — �3� s �: : .� � : : : __: _.__.. .: ._ _ _ o . ._ _ _ . _. . __ _ _ . ._.. y ... _ � : _ : . . . [ _ ; . ; � vsE �` x �o ' = �oa s�- .-�� --�. SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT KING COUNTY. �VASHIrIGTON, SURFACE WATER DESIGN MANUAL STORMWATER FACILITY SUI�ZMARY SHEET � - Development �IrK w�,A-s 11nL�LT Date _ Location � C — N � � �S —2 3 — $ � ENGINEER DEVELOPER Name Name � Firm j�.rL Firm • Address p , Address ,q cJ p L Phone 2 •O L o Phone Developed Site: Acres 2-ZS�- Number of lots 1 4 Number of detention facilities on site: Number of infiltration facilities on site: � ponds ponds - vaults vaults tanl:s tanks Flow control provided in reo onal facility(b ve location) � No flow control required Exemption number Downstream Drainaoe Basins Immediate Ma'or Basin Basin A Basin B Basin C Basin D. Number&type of water quality facilities on site: biofiltration swale(regular/wed or sand filter(basic or large?) continuous inflow?} sand filter,lineaz(basic or large?) . �_combined deten' n/WQ pond sand filter vault(basic or large?) (WQ portio basic �r larae?) combmP detentionlwetvault stormwater wedand • composi fiiter wetpond(basic or large?.) filter s�-ip wetvault flow dispersion farm management plan landscape management plan oiUwater separator(baffle or coalescing plate?) catch basin inserts:Manufacturer pre-settlina pond pre-setdin�structure:Manufacturer flow-splitter catctibasin DESIGN INFORMATION INDIVIDUAL BASIN A ' B C D �Vater Qualit desi�n flow VS'ater Qualit treated volume or wet ond Vr 1993 Surface Water Design b4anual 9/119f 1 KING COUNTY, �VASHINGTON, SURFACE WATER DESIGN MANUAL - DESIGN TOTAL INDIVIDUAL BASIN - ' INFORMATION,cont'd . Drainage basin(s) A B C D Onsite area - Offsite area ' T e of Stora�e Facilit N Live Stora�e Volume Predevelo ed Runoff Rate 2- ear 10- ear .t 2 Z 100- ear ,'Lo Develo ed runoff rate 2- ear . 2 10- ear O • 5 100- ear O . T e of restr-ictor Size of orifice/restriction No. 1 �' �� No.2 �T ` No.3 No.4 FLOW CONTROL&WATER QUALITY FACII.ITY SIJ1vIIviARY SHEET SKETCH All detention,infiltration and water quality facilities must include a sketch per the following criteria: � 1. Heading for the drawinas should be located at the top of the sketch(top right-hand corner). � The headina should contain: • North atrow(point up or to left) �• D9� � • Plat name or short plat number. •Address(nearest) • Date drawn(or updated) •Thomas Brothers page,grid number 2. Label CBs and MHs with the plan and profile designation. Label the control structure in writing or abbreviate with C.S. Indicate�-hich structures provide spill control. 3. Pipes--indicate: � Pipe size Pipe len�th Flow d'uection Use s single heavyweight line 4. Tanks—use a double,heavyweight line and indicate size(diameter) 5. Access roads � • Oudine the limits of the road • Fill the oudine with dots if the road is gravel. Label in�vritin�if another surface. 6. Other Standard Symbols: • Bollards:• • e• a ■ a �t • Rip rap o00000 000000 Fences --x---x---x---x---x---x--- • Di[ches —D---�D---�-D---�D � 7. Label trash racks in wTiang. 8. Label all streets v�rith the actual street siQn designation. If you don't know the actual street name,consult the plat map. 9. Include easements and lot lines or tract limits when possible. 10. Arrange all the labeling or writing to read from left to right or from bottom to top with reference to a properly oriented headin�. 11. Indicate driveways or features that may impact access,maintenance or replacement. 9/]/98 ]998 Surface Water Design Manual 2 SECTION 10 OPERATIONS AND MAINTENANCE MANUAL KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL � APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DR.AINAGE FACILITIES N0. 1 -DETEMION PONDS Maintenance Defect Conditions When Maintenance Resuits Expected When Component Is Needed Maintenance Is Pertormed General Trash&Debris My trash and debris which exceed 1 cubic foot Trash and debris deared from sfte. per 1,000 square feet(this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Poisonous Vegetation Any poisonous or nuisance vegetation which No danger of poiso�ous vegetation may oa�stitute a hazard to County pe�sonnel or where County personnel or the the public. public might normally be. - (Coordination with Seattle-King County Health Departrnent) . Pdlution Od,gasoGne,or other contaminants of one No contaminants present other Than gallon or more or any amount found that could: a surface film. (Coordinatio�rvith 1)cause damage to plant,animal,or marine I'rfe; Seatde/IG�g Co�ty Health 2)constitute a fire hazard;or 3)be flushed DepartrneM) downstream during rain storms. Unmowed GrassJ If faciGty is located in private residential area, When mowing is needed, Ground Cover mowing is needed when grass exceeds 18 grass/ground cover should be inches in height. In other areas,the general mowed to 2 inches in height. policy is to make the pond site match adjacent Mowing of selected higher use ground cover and terrain as long as there is no areas�ather than ihe entire slope interference with the function of the faality. may be acceptable for some situations. Rodent Hdes Any evidence of roderrt hdes if faality is acting RodeMs destroyed and dam or as a dam or berm,or any evidence of water bem►repaired. (Coordination with piping ihrough dam or berm via rodent holes. SeattlelKing CouMy Health Deparbnent) Insects When insects such as wasps and homets Insects destroyed or removed from interfere with maintenance activities. site. Tree Growih Tree growth does not allow maintenance access Trees do not hinder maintenance or interferes with maintenance activity(i.e.,slope activities. Selectivefy cultivate trees mowing,sift removal,vactoring,or equipment such as alders for firewood. movements). If trees are not interfering with access,leave trees alone. Side Slopes of Pond Erosion E�oded damage over 2 inches deep where Slopes should be stabilized by cause of damage is still present or where there using appropriate erosion control is potentiat for continued erosion. measure(s);e.g.,rock reinforcement,planting of grass, compaction. Storage Area Sediment Accumulated sediment that exceeds 10°k of the Sediment cleaned out to designed designed pond depth. pond shape and depih;pond reseeded if necessary to control erosion. Pond Dikes Settlements Any part of dike which has settled 4 inches lower Dike should be built back to the than the design elevation. design elevation. Emergency Rock Missing Only one layer of rock exists above native soil in Replace rocks to design standards. Overflow/Spllway area five square feet or larger,or any exposure of native sal at the top of out flow path of spillway. Rip-rap on inside slopes need not be replaced. 1998 Surface Water Design h-lanual 9/1/98 A-1 APPENDIX A MAINTENANCE STANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACILTITES I NO.2-INFILTRATION Maintenance Defect Conditions When Maintenance Results Expected When Component is Needed Maintena�ce Is Performed General Trash&Debris See'Ponds'Standard No.1 See'Ponds'Standard No.1 Poisonous Vegetation See'Ponds'Standard No.1 See'Ponds'Standard No.1 Pdlution See'Ponds'Standard No.1 See'Ponds'Standard No.1 Unmowed Grass/ See'Ponds'Standard No.1 See'Ponds'Standard No.1 Ground Cover , Rodent Hdes See'Ponds'Standard No.1 See'Ponds'Standard No. 1 Insects See'Ponds'Standard No.1 See'Ponds'Standard No.1 Storage Area Sediment A percolation test pit or test of facility indcates Sediment is removed and/or faciliry facility is only working at 90%of its designed is cleaned so that infiftration system capabilities. If two inches or mo�e sediment is works according to design. present,remove. ' Sheet Cover(If Sheet cover is visible and has more that three Sheet cover repaired or reptaced. Applicable) 1/4-inch holes in it. Sump Filled wiU� Any sediment and debris filling vault to 10'/0 of Clean out sump to design depth. Sediment and Uebris depth from sump bottom to bottom of outlet pipe , (If Applicable) or obstruding flow into U�e connector pipe. F�7ter Bags Flled with S�ment Sediment and debris fiA bag more than 1/2 fuU. Replace fitter bag or�edesign and Debris system. Rodc Flters Sediment and Debris By visual inspecdon,little or no water flows Replace gravel in rock fiRer. through fitter during heavy rain stortns. Side Slopes of Pond Erosio� See'Ponds'Standard No.1 See'Ponds'Standarci No.1 Emergency Rock Missing See'Ponds'Standard No.1 OveAfow Spillway Settting Ponds and Sediment Remove when 6'or more. Vaults � Note: Sediment accumula6on of more ihan 25 inches per year may indicate excessive erosion is occurring upstream of�e facility or that I conveyance systems are not being propedy maintained. The contributing drainage area should be checked for erosion proWems or � inadequate maintenance of conveyance systems if excessive sedimentation is noted in an infiltraGon facility. il Check twice a year during 6rst 2 years o!operation;orxx.s a year thereafter. pean manholes/catch basins,repair damaged inlets/outlets, dean trash racks. � 9/1/98 1998 Surface Water Design Manual A-2 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES , NO.3-CLOSED DETENTION SYSTEMS(PIPESlTANKS) Maintenance Defect Conditions When Maintenance is Needed Resutts Expected When Component Maintenance is Performed Storage Area Plugged Air Vents One-hatf of the cross section of a vent is blocked at Vents free of debris and any poiM with debris and sediment sediment Debris and Accumulated sediment depth exceeds 109'0 of the All sedime,nt and debris Sediment diameter of the storage area for 14 length of storage removed from storage area. I vault or any point depth exceeds 15%of diameter. � Example:72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more I ihan l�length of tank ' Jants Beriveen Any crack allowing material to be transported into All joint between tank/pipe I� Tank/Pipe Sec6on facility sections are sealed Tank Pipe Bent Any part of tank/pipe is bent out of shape more than TanW pipe repaired or replaced Out of 5hape 109'0 of iYs design shape to desi�. Manhole Cover Not in Place Cover is missing or only parti�ly in place.My open Manhole is dosed. manhole requires mairrtenance. Lodcing Mechanism camot be opened by one maintenance Mechanism opens with proper Mechanism Not person with proper tools.Bolts into frame have less tools. II Working than 3�4 inch of thread(may not appty to self-locking lids.) I Cover Difficuft to One maintenance person cannot remove lid after Cover can be removed and Remove applying SOlbs of lift. Intent is to keep cover from reinstalled by one mamtenance s�ng off access to maintenance. person. Ladder Rungs KWg Co�ty Safety Otfice and/or maintenance person Ladder meets design standards Unsafe judges that ladder is unsafe due to missing rungs, aUow�maintenance person safe misalignment,nist,or cracks. access. Catch Basins See`Catch Basins'Standards No.5 See'Catch Basins'Standards No.5 1998 Surface 1Water Desi�►Manual 9/1/98 A-3 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES , NO.4- CONTROL STRUCTURE/FLOW RESTRICTOR Mai�tenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed General Trash and Debris Distance between debris build-up and bottom of All trash and debris removed. (Includes Sediment) orifice plate is less than 1-1/2 feet Stnictura!Damage Structure is not securely attached to manhole wall Structure securely attached to a�d outlet pipe structure should support at least wall and ouUet pipe. 1,000 Ibs of up or down pressure. Stn�cture is not in upright position(allow up to Structure in correct position. 10%from plumb). Cornections to oudet pipe are not watertight and Connections to ouUet pipe are show signs of rust. water tigh�structure repaired or replaced and worfcs as designed. Any holes—other than designed holes—in the Structure has no holes other structure. than designed holes. Cleanout Gate Damaged or Missing Cteanart gate is not watertight or is missing. Gate is watertight and wo�ics as designed. Gate cannot be moved up and down by one Gate moves up and down easily maintenance person. and is watertight. (�ain leadng to gate is missing or damaged. Chain is in place and works as designed. Gate is rusted over 5096 of its surface area. Gate is repaired or replaced to meet design standards.. �'� Orifioe Plate Damaged or Missing Control device is not wa�king properly due to Plate is in place and works as missing,out of place,or be�t orifice plate. designed. Obstructions Any trash,debris,sediment,or vegetation Plate is free of all obstructions blocking the plate. and works as designed. Overflow Pipe Obstruc6ons Arry trash or debris blocking(or having the Pipe.is free of all obstructions potential of bbdcing)the overflow pipe. and works as designed. Mantwle See`Closed Detention Systems"Standards No.3 See`Closed Detendon Systems' Standards No.3 Catch Basim See`Cartch Basins'Standards No.5 See'Catch Basins"Standards No.5 9/1/98 1998 5urface Water Desian Manual A-4 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES , NO. 5-CATCH BASINS Maintenance Defect Conditions When Maintenance fs Needed Resutts Expected When Component Maintenance is performed General Trash 8�Debris Trash or debris of more than 1/2 cubic foot which is No Trash or debris located (InGudes Sedime�t) located immediately in front of the catch basin immediately in front of catch opening or is blocking capaaty of the basin by basin opening. more than 10% Trash or debris(in the basin)that exceeds 1/3 the No trash or debris in the catch depth from ihe bottom of basin to invert the lowest basin. pipe into o�out of tt►e basin. Trash or debris in any inlet or outlet pipe blocking infet and outlet pipes free of more than 1/3 of its height trash or debris. Dead arrmals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within the catch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which votume would attract or support the breeding of insects w rodents. Structure Damage to Comer of frame extends more than 3/4 inch past Frame is even with curb. Frame and/or Top Slab curb face into the street(If applicable). Top slab has hdes larger Than 2 square inches or Top slab is free of holes and cracks wider than 1/4 inch(intent is to make s,.,e cracks. all material is running irrto basin). Frame not sitting flush on top slab,i.e.,separation Frame is sitting flush on top of more than 3/4 inch of the frame from the top slab. slab. Cracks in Basin Walls/ Cracks wider than 1/2 inch and longer than 3 feet, Basin replaced or repaired to , Bottom any evidence of soil particles entering catch basin design standards. through cracks,or mainte�ance person judges that structure is unsound. Cracks wider than t/2 inch and longer than 1 foot No cracks more than 1/4 inch at the joint of any inleU outlet pipe or any evidence wide at the joint of inleUouUet of soil partides entering catch basin through pipe. cracks. SedimenU Basin has settled more than 1 inch or has rotated Basin replaced or repaired to Misalignment more than 2 inches out of alignment design standards. 1998 Surface Water Design Manual 9/1/98 A-5 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILIT'IES ' NO.5-CATCH BASINS(CONTINUED� Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is pertormed Fire Hazard Prese�ce of chemicals such as natural gas,al and No flammable chemicals gasoline. present. Vegetation Vegetation growing across and bbcking more ihan No vegetation bbcking opening 10%of the basin opening. to basin. Vegetation growing in inleUoutlet pipe joints that is No vegetation or root growth more than six inches tali and less than six inches present apart. Pollution Nonflammable chemicals of more than 1/2 cubic foot No pollution present other than per three feet of basin length. surface film. Catch Basin Cover Cover Not in Place Cover is missing or only partialty in place.Any open Catch basin cover is closed catch basin requi�es maintenance. . Locking Mechanism Mechanism cannot be opened by on maintenance Mechanism opens with proper Not Working person with proper tools.Bolts into frame have less tools. than 1/2 inch of thread. Cover Difficult to One maintenance person cannot remove lid after Cover can be removed by one Remove applying 801bs.of Gft;iMent is keep cover from maintenance person. sealing off access to mairrtenance. Ladder Ladder Rungs Ladder is unsafe due to rtrssing rungs,misalignment, Ladder meets design standards Unsafe rust,aacks,or sharp edges. and albws maintenance person safe access. Metal Grates Grate with opening wider tlian 7/8 inch. Grate opening meets design {If Applicable) standards. Trash and Detrris Trash and debris that is blocldng more than 20%of Grate tree of trash and debris. grate surface. Damaged or Grate missing or broken member(s)of the grate. Grate is in place and meets Missing. design standards. NO.6 DEBRIS BARRIERS(E.G.,TRASH RACKS) Maintenance Defect Condition When Maintenance is Needed Results Expected When Components Maintenaoce is Pertormed. General Trash and Debris Trash or debris that is plugging more than 209'a of Barrier dear to receive capacity the openings in the barrier. flow. Metal Damaged/Missing Bars are bent out of shape more than 3 inches. Bars in place with no bends more Bars. U�an 3/4 inch. Bars are missing or entire barrier rrrissing. Bars in place according to design. Bars are loose and rust is causing 509'o deterioraUon Repair or replace barrier to to any part of bamer. design standards. 9/1/98 1998 Surface Water Design Manual A-6 APPEAIDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACII,ITIES , NO.7-ENERCY DISSIPATERS Maintenance Defect Conditions When Maintenance is Needed Results Expected When Componenis Maintenance is Pertormed. �i Extemal: �I Rock Pad Missing or Moved Only one layer of rock exists above native soil in Replace rocks to design Rodc area five square feet or larger,or any exposure of standards. native soii. Dispersion Trench Pipe Plugged with Accumulated sediment that exceeds 20%of the Pipe cleaned/flushed so that it Sediment design depth. matches design. Not Discharging �sual evidence of water discharging at Trench must be redesigned or Waier Property concentrated points along trench(normal condition rebuift to standards. is a'sheet floW'of water along Vench).Intent is to prevent erosion damage. Pe�forations Over 1/2 of pertorations in pipe are plugged with Clean or replace perforated pipe. Plugged. debris and sediment. Water Flows Out Maintenance perso�observes water flowing out Faality must be rebuilt or Top of"Distributo�' during any stoRn less than the design storm or its redesig�ed to standards. Catch Basin. causing or appears likely to cause damage. Receiving Area Water in receiving area is causing or has pote�tial No danger ot landslides. � Over-Saturated of causing landslide problems. Intemal: Manhole/Chamber Wom or Damaged SUucture�ssipating flow deteriorates to 1/2 or Aeplace structure to design Post Baffles,Side original size or arry concentrated wom spot standards. of Chamber exceeding one square foot which would make structure unsound. Other Defects See"Catch Basins"Star►dard No.5 3ee`Catch Basins'Standard No. 5 1998 Surface Water Design Manual 9/1/98 A-7 APPENDIX A MAINTENANCE STANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACILITIES NO.8-FENCING ' Maintenance Defect Conditions When Maintenance is Needed Results Expected When Components Maintenance is Performed General Missing or Broken My defect in the fence that permits easy enVy Parts in place to provide adequate Parts to a facility. security. Erosion Erosion more than 4 inches high and 12-18 No opening under tfie fence that inches wide permitting an opening unde�a exceeds 4 inches in height. fence. Wire Fences Damaged Parts Post out of plumb more than 6 inches. Post plumb to within 1-1/2 inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence(including post,top rails,and Fence is aligned and meets design fabricj more than 1 foot out of design alignment. standarcls. Missing or loose tension wire. Tension wire in place and holding fabric. Missing or loose barbed wire that is sagging Bacbed wire in place with less than more U�an 2-1/2 inches behnreen posts. 3/4 inch sag between post. Extension artn missing,broken,or bent out of Extensio�arm i�place with no shape more than 1 1/2 inches. bends larger Uian 3/4 inch. Deteriorated PaiM or Part or parts that have a rusting or scaling SUucturally adequate posts or Protective Coating oaiditio�that has affected sVuctural adequacy. parts with a unifortn protective coating. Openings in Fabric Ope�ings in fabric are such that an 8-inch- No openi�gs in fabric. diameter baA could fit through. NO.9-GATES Maintenance Defect Conditions When Maintenance is Needed Resufts Expected When Compone�t . Maintenance is Pertormed General Damaged or Missing M"issing gate or locking devices. Gates and Locking devices in Members P�ce• Broken or missing hinges such that gate cannot Hinges intact and lubed.Gate is be easity opened and closed by a maintenance working freely. Person. Gate is out of plumb more than 6 incfies and Gate is aligned and vertical. more than 1 foot out of design alignment. Missing stretcher bar,stretcher bands,and ties. Stretcher bar,bands and ties in place. Openings in Fabric See"Fencing"Standard No.8 See"Fenang'Standard No.8 9/1/98 1998 Surface Water Design Manual A-8 APPENDIX A MAII�T'ENANCE STANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACILITIES , N0. 10-CONVEYANCE SYSTEMS(PIPES&DITCHES) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment 8 Debris Accumulated sediment that exceeds 20%of the Pipe cleaned of all sedime�t diameter of the pipe. and debris. Vegetation Vegetation that reduces free moveme�t of water All vegetatio�removed so water through pipes. flows freety through pipes. Damaged Protective coating is damaged;rust is causing Pipe repaired or replaced. more than 50%deterioration to any part of pipe. My dent ihat decreases the cross section area of Pipe repaired or replaced. pipe by more than 20°k. Open Ditches Trash&Debris Trash and debris exceeds t cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20%of the Ditch deaned/flushed of all design depth. sediment arxi debris so that it matches design. Vegeta6on Vegetation that reduces iree movement of water Water flows freely through through ditche.s. ditches. Erosion Damage to See'Ponds'Shandard No.1 See"Ponds'Standard No.1 ' Slopes Rock Lining Out of Maintenance person can see native soi!beneath Replaoe rocks to design Place or Missing(If the rocic lining. standards. Applicable). Catch Basir►s See`Catch Basins:Standard No.5 See"Catch Basins'Standard r�u.s Debris Barriers See"Debris BaRiers'Standard No.6 See"Debris Barriers'Standard (e.g.,Trash Rack) No.6 N0. 11 -GROUNDS(LANDSCQPING) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed General Weeds Weeds growing in mwe than 20%of the landscaped Weeds present in less than 5% (Nonpoisonous) area(trees and shn�s only). of 1he landscaped area. Safety Hazard Any presence of poison ivyr or othe�poisonous No poisonous vegetation vagetation. prese�t in landscaped area. Trash or Litter Paper,cans,bottles,totaling more than 1 cubic foot Area clear of litter. • within a landscaped area(trees and shrubs only)of 1,000 square feet Trees and Shrubs Damaged Limbs or parts of trees or shrubs that are split or Trees and shrubs with less than broken which affect more than 25°�of the total 5%of total foliage with split or foliage of the tree or shrub. broken limbs. Trees w shrubs that have been blown dow�or Tree or shrub in place free of knocked over. injury. Trees or shrubs which are not adequately supported Tree or shrub in place and or are leaning over,causing exposure of the roots. adequately supported;remove any dead or diseased Vees. 1998 Surface Water Design Manual 9/1/98 A-9 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACII.ITIF.S ' N0. 12-ACCESS ROADS/EASEMENTS Malntenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Pertormed General Trash and Debris Trash and debris exceeds 1 cubic foot per 1,000 Roadway free of debris which square feet i.e.,trash and debris would fill up could damage tires. one standards size garbage can. Blodced Roadway Debris which could damage vehide tires(glass Roadway free of debris which or metal). could damage tires. My obstniction which reduces dearance above Roadway overtiead dear to 14 feet road surface to less than 14 feet high. Any obstruction restricting the access to a 10 to Obstruction removed to allow at 12 foot widfh for a distance of more than 12 feet least a 12 foot access. or any point restricting access to less than a 10 foot widlh. Road Surface Settlement,Pottwles, When any surface defect exceeds 6 inches in Road surface unifom�ly smooth Mush Spots,Ruts depth and 6 square feet in area.In general,any with no evidence of settlement, surface defect which hinders or prevents potholes,mush spots,or ruts. maintenance access. Vegetation in Road Weeds growing in the road surface that are Road suriace free of weeds taller Suriace more than 6 inches tall and less than 6 inches than 2 irxhes. tall and less than 6 inches apart within a 400- square foot area. Modular Grid Build-up of sediment mildfy contaminated with Removal of sedimeM and disposal Pavement petroleum hydrocarbons. in keeping with Health Departrnent recommendations for mildly � coniaminated soils or catch basin sediments. Shoulders and Erosion Damage Erosion within 1 foot of the roadway more than 8 Shoulder free of erosion and Ditches inches wide and 6 inches deep. matching the suRounding road. � Weeds and Brush Weeds and brush exceed 18 inches in height or Weeds and bnish cut to 2 inches hinder maintenance access_ in height or deared in such a way as to albw maintenance access. i i • � . I 9/1/98 1998 Surface Water Design Manual A-10 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATII.Y MAINTAINED DRAINAGE FACILTIIES ' N0. 13-WATER QUALITY FACILIIIES A.) Biofiltration Swale Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Pertormed Biofittration swale Sediment Aocumulation Sediment depth exceeds 2•inches No sediment deposits on grass on Grass Layer layer of the bio-swale,which would impede filtradon of nuwff. Vegetation When the grass becomes excessively tall Vegetation is mowed or nuisance (greater than 10-inches);when nuisance weeds vegetation is eradicated,such that and other vegetation starts to take over. flow not impeded.Grass should be mowed to a height between 4 inches and 9 inches. lnlet Outlet Pipe InIeU outlet ppe clogged with sediment and/or No clogging or blockage in the iNet debris. and outlet piping. Trash and Debris Trash and debris accumdated in the bio-swale. Trash and debris removed from Accumulation bioswale. Eros'aN Scouring Where the bio-swale has eroded or scoured Bioswale sFauld be re-graded and the bottom due bo flow channelization,or hi�er re-seeded to specification,to flows. eliminated channeled flow. Overseeded when bare spots are evident. N0. 13-WATER QUALITY FACILITIES(CONT/NUED� B.) Grasslined Filter Strips Maintenance Defect Condition When Maintenance is Needed Results EzFe:ted When Component Maintenance is Pertortned Filter Strip Sediment Accumulation Sediment depth exceeds 2 inches. No sediment deposits on grass on Grass Layer layer of the filter strip,which would impede fittration runoff. Vegetation 1Nhen the grass becomes excesslvely tall VegetaUon is mowed or nuisance (greater than 1 U-inches);when nuisance weeds vegetation is eradicated,such that and other vegetation starts to take over. flow not impeded.Grass should be mowed to a height between 4 � inches and 9 inches. Trash and Debris Trash and debris accumulated on the fitter Trash and Debris removed from Accumulation strip. filter. ErosioN Scouring Where the fifter strip has e�oded or scoured Strip should be re-graded and re- due to flow channelization,or higher flows. seeded specification,to eliminate channeled flow.Overseeded when bare spots are evident. V-Notch Pipe Weir When the V-Notch pipe becomes damaged or Cleaned and properly functioning clogged with sedimenU debris. weir,such that flows uniformly spread. 1998 Surface Water Design Manual 9/1/98 A-11 APPENDIX A MAINTENANCE STANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACILI'TIFS ' C.)Wetponds Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed - Wetpond Vegeta6on Vegetation such as grass and weeds need to be Vegetation should be mowed to mowed when it starts to impede aesthetics of pond. 4 to 5 inches in height. Trees Mowing is generally required when height exceeds and bushes should be removed 18-inches.Mowed vegetation should be removed where ihey are interfering with from areas where it could eMer the pond,either pond maintenance activities. when the pond level rises,or by rainfall runoff. Trash and Debris Accumulation that exceeds 1 CF per 1000-SF of Trash and debris removed from pond area. pond. InIeU Outlet Pipe InIeU Outlet pipe dogged with sediment and/or No dogging or blockage in the debris material. inlet and ouUet piping. Sediment Sediment accumulations in pond bottom that Removal of sediment from pond Accumulation in Pond exceeds the depth of sedimeM zone plus 6-inches, bottom. Bottom usually the first cell. Oil Sheen on Water Prevalent and visible oil sheen. Removal of sediment from po�d ' bottom. Erosion Erosion of the pond's side slopes and/or scouri�g of Slopes should be stabilized by the pond bottom,that exceeds 6-inches,or whe�e using proper erosion coMrol continued erosion is prevalent measures,and repair methods. Settlemerrt of Pond My part of these components that has settled 4 Dike/berm is repaired to Dike/Berm inches or lower than the design elevation,or speafications. inspector detertrines dike/beRn is unsound. Rodc Window Rodc windcw is clogged with sediment wndow is ftee of sedment and debris. Overtlow Spillway Rodc is missing and so�is exposed at top of Replace rocks to specifications. . spillway or outside slope. 9/1/98 1998 Surface Water Design Manual A-12 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILTTIFS , N0. 13-WATER QUALITY FACILITIES(CONTINUED� D.)Wetvaults Maintenance Defect Condition When Maintenance is Needed Results Expected When ComponeM Maintenance is Performed Weivault Trash/Debris Trash and debris accumufated in vault,ppe or Trash and debris removed from Accumulation inleU outlet,(ncludes floatabies and non- vault. floatables). Sediment Accumulation Sediment accumulation in vauk bottom that Removal of se�ment from vault in Vault exceeds the depth of the sediment zone plus 6- inches. Damaged Pipes InIeU outlet pping damaged or broken and in Pipe repaired and/or replaced. need of repair. Access Cover Cover camot be opened or removed,especially Pipe repaired or replaced to Damaged/Not Worldng by one person. proper working speafica6ons. VauR Structure Vault Cradcs wider than 1/2-inch and any No cracks wider than 1/4inch at Damaged evidence of soil particles entering the sVucture the joiM of the inleU outlet pipe. ttuough the aacks,or maintenance!inspection Vault is detemiined to be persornel determines that the vault is not structurally sound. structurally sound. Baffles Baffles corroding,craclang,warping and/or Repair or replace baffles to � showing signs of failure as determined by specifications. mainienance/inspectio�staff. Access Ladder Damage Ladder is coRoded or deteriorated,not functioning Ladder replaced or repaired to property,missing nxgs,has cradcs and/or specifications,and is safe to misaligned. use as detemiined by inspection personnel. 1998 Sudace Water Design Manual 9/1/98 A-13 APPENDIX A MAIN'IENANCE STANDARDS FOR PRNATELY MAINTAINED DRAINAGE FACII.ITIES , N0. 13-WATER QUALITY FACILITIES(CONT'lIYUED� E.) Sand Fiiters Maintenance Defect Condition When Maintenance is Needed Results Expected When Compo�ent Maintenance is Pertormed Above Ground Sediment Sediment depth exceeds 1/2-inch. No sediment deposit on grass Accumutation on Grass layer of sand filter which wouid Layer impede pertneability of the filter section. Trash and Debris Trash and debris accumulated on sand filter bed. Trash and debris removed from Accumulations sand filter bed. SedimenU Debris in When the yard drain CB's and dean-out become Sediment,material f�om the Yard Drains/Clean- full or partially plugged with sedime�t and/or CB's and clean-outs removed. Outs] debris. Vegetation When the grass becomes excessively tall(greater Vegetation is mowed or than 6-inches);wheti nuisance weeds and other nuisance vegetation is vegetation starts to take over. eradicated,such that flow is not impeded. Sand Filter Media Drawdorm of water through the sand fifter media, Usually requires replacement of takes longer than 24hours,and/or flow ttuough top 6 to 12-inches of inedia the overflow pipes occurs frequentfy. May require reptacement of en6re sand filter section, depending on sec6on. Prolonged flows Sand is saturated for prolonged periods of time Limit the bw,continuous flows (severaf weeks)and does not dry out between to a smalt portion of the facility storms due to continuous base flow or prolonged by using a low wooden divider or flows from detention faalities. slightly depressed sand surface. Short G�cuiting When flows become concentrated over the sand Flow arxi pe�colation of water filter rather thar�aspersed. through the sand fitter is un'rform and dispersed across the filter - section. Erosion Damage to Erosion over 2-inches deep where cause of Slopes should be stabilized by Slopes damage is prevalent or potential for continued using proper erosion control erosion is eviderrt. measures. Rock Pad Missing or Soil beneath the rodc is visible. Replace or rebuild the rock pad Out of Place to design specifications. V-Notch Pipe Weir When the V-Notch pipe becomes damaged or Clean and property func[i�ing clogged with sedimenU debris. weir,such that flows unifoRnly spread. Damaged Pipes Any part of the piping that is crushed or defomied Pipe repaired or replaoed. more than 20%or any other failure to the pipi�g. Below Ground Sediment Sediment depth exceeds 1/2-inch. No sediment deposits on sand Vautt. Accumulation on Sand filter section,which would Media Sec2ion impede peRneability of the filter section. Sediment Sediment depth exceeds 6-inches in vault bottom. No sediment deposit in the first Accumulation in Vault chamber of the vault. Trash/Debris Trash and debris accumulated in vault,or pipe Trash and debris removed from Accumulation inleU outlet,floatables and non-floatables vault,and inleU ouUet piping. Sediment in Drain When drain pipes,deanouts,and yard drains Remove the material from the Pipes/Yard Drains/ become full with sediment and/or debris. faatities. Cleanouts 9/1/98 1998 Surface Water Design Manual a-la � �' I _ APPENDIX A MAINTENANCE STANDARDS FOR PRIVATEI.Y MAINTAINED DRAINAGE FACII.ITIES I' ' N0. 13-WATER G1UALITY FACILIIIES(CONTINUED� E. Sand Filters(Continued) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Below Ground Short Circuiting When seepage/flow occurs along ihe vauR walls Sand filter media section re-laid Vault{Continued) and comers. and compacted along perimeter of vauft to foRn a semi-seal. Vertical Riser Pipes Plugged,failure due to cracking deformation.Flows Clean out the riser pipe;replace tend to back-up in first chamber of the vault pipe as needed. Damaged Pipes Inlet or outlet piping damaged or broken and in Pipe repaired and/or replaced. need of repair. Access Cover Cove�cannot be opened,one person cannot open Cover repaired to proper Damaged/Not the cover,corrosioN deformation of cover. working specifications or Working replaced. Vault Structure Cracks wider than 1/2-inch and arry evidence of soil Vault replaced or repaired to Damaged:Indudes partides entering the structure through the cracks, design specifications. Cracks in Walts, or maintenance!inspection personnel determines Bottom,Damage to that the vault is not structurally sound. Frame and/or Top Slab. Cracks wider than 1/2-inch at the joints of any inleU No cracks more tfian 1/4-inch outlet pipe or any evidence of soil partides entering wide at the joint of tlie inleU the vault through the walls. outlet pipe. Baffles Baffles corro�ng,cradd�g,warping and!or showing Repai�or replace baffles to signs of failure as determined by maintenance/ specifications. inspec�tion person- Access Ladder Ladder is corroded or deteriorated,not fuictioning Ladder replaced or repaired to Damaged properly,missing rungs,cracks,and misaligned. speafications,and is safe to use as determined by inspection personnel. I998 Surface�Vater Design Manual 9/1I98 A-15 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITTES ' N0. 13-WATER QUALITY FAClUTIES(CONTINUED� F. Leaf Compost Filters Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Pertormed Above Ground Sediment Sediment depih exceeds�.25-inches. No sediment deposits on fabric Open Swale accumulation on Geo- layer which would impede Textile/media permeability of the fabric. Trash and debris Trash and debris accumulated on compost fiRer Trash and debris removed from accumulations bed. . compost filter bed. SedimenU debris in When the yard drain C8's and clean-outs become Remove the accumulated drain!yard drains/ full of sediment and/or debris_ material from the facility. Gean-outs. Vegetation Vegetation impending flow through section,or Vegetation is mowed or encroaching into compost media. eradicated such that flow is no longer impeded. I Leaf Compost Media Drawdovm of water through the leaf compost, Replace media with new to takes longer than 12-hours,and/or flow through design specifications,in addition the overflow pipes oocurs frequenGy. to replacing fabric. Short-Circuiting When C�ianneled flow occurs over fhe leaf inedia; Flow is uniform over the entire and where flow perks ttuough the media at the width of the media section,and baNles. concemrated percolation does not occur at the baffle walls. Media needs to be graded and re-set at the baffles to form a ' seal.Weir plate may need to be adjusted in addition. . Erosion Damage to Eroded damage over 2-inches deep where cause Slopes should be stabilized by Slopes of damage is prevalent or potential for continued using proper erosion control ' i erosion is prevalent. measures. Damaged Geo-Textile When fabric is tom,deteriorated,raveled,eta Fabric repiaced as necessary. Fabric. Rock Pad Missing or Soil beneaih the pad is visible. Replace or rebuild ttie rock pad out of ptace to desic,�standards. Damaged Pipes My part of the pipe system that is crushed, Pipe repaired or replaced. damage due to coRosion,and/or settlement V-Notch Weir Flow is not being uniformly spread over filter Clean,repair or replace the weir Assemblies media. systems. Below Ground Sediment Sedment depth exceeds 025-inches. No sediment deposits on fabric Vauft Accumulation on Geo- layer which would impede Texdlel Media. pertneability of the fabric and ' compost media. Sediment SedimeM depth exceeds 6-inches in first chamber. No sediment deposits in vauft Accumulatio�in VauR bottom of first chamber. � Trash/Debris Trash and debris accumulated on compost filter Trash and debris removed from Accumulation bed. the compost filter bed. Sedimerrt in Drain When drain ppes,dean-outs,yard drains become Remove tfie accumulated Pipes/Yard Drains/ full with sediment and/or debris. material from the facilities. Clean-0uts 9/1/98 1998 Surface Water Design hlanual A-16 _ APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILITIES ' N0. 13-WATER QUALITY FACILITIES(CONTlNUED) F. Leaf ComNost Filter(Continued) Maintenance Defect Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Below Ground Leaf Compost Meda Drawdown of water through the leaf compost,takes Replace media with new longer ihan 12-hours,and/or overflow occurs compost to specifications,in frequently. addition to replacing fabric. Short Circuiting When seepage occurs along the vauft wall and Percolation of water occurs comers occur. abng the walls and comers and not ttxough the media section. . Media needs to be re-set along the vault waN and comers to form a semi-seal. Plugged/Damaged Flow tends to backup unusuaily high in the first Clean out the elbow fittings and/ Elbows chamber of the vauft. or replace'rf damaged. Damaged Geo-Textile Fabric is tom,deteriorated,raveled,etc. Fabric replaced as necessary. Fabric Rock Pad Missing or Soil beneath the pad is visible. Replace or rebuild the rodc pad Oui oi Place to design standards. Damaged Pipes My part of the pipes that are crushed,damaged Pipe repaired andl or replaced. due to corrosion and/or settlement Access Cover Cover carxwt be opened,one person cannot open Cover repaired to proper Damaged/Not the cover,corrosaN deformation of cover. working speaficatio�s or Working replaced. V-Notch Weir Flow dces not spread un'rfortnly over filter media by qean,repair and/o�replace the Assemblies weir section. weir plate section,or adjust height Vault Structure Cracks wider than 1/2-inch and any evidence of soil Vault replaced or repaired to Indudes Cracks in partides entering the structure through the cxacks, design specifications. Wall,Bottom, or maintenance/inspection personnel determines Damage to Frame tliat the vault is not sVucturally sound. 2nd/of Top Slab Baifles Baffles corroding,cradcing warping,and/or showing Repai�or replace baffles to signs of failure as detemiined by maintenance/ specification. inspection person. Access Ladder Ladder is corroded or deteriorated,not fu�ctioning Ladder replaced or repaired and Damaged property,missing rungs,cradcs,and misaligned. meets specifications,and is safe to use as determined by inspection persorx�el. Cracks wider than 1/2-inch at the joint of any No cracks more than 1/4-inch inleUoutlet pipe or any evidence of soil particles wide at the joint of the in1eU entering the vault through She walls. outlet pipe. 1998 Surface Water Design b7anual 9/1l98 A-17 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILTTIES ' N0. 13-WATER QUALITY FACILIl1ES{CON77NUED� G. Infiltration Ponds Mainte�ance Defect Condition When Maintenance is Needed Results Expected When Component MaiMenance is Performed _ Infiltration Pond Vegetation Vegetation such as grass and weeds needs to be Vegetation should be mowed to mowed when it starts to impede infiltration functio�. 2-inches in height Trees and Mowing is gene�ally required when height exceeds bushes should be removed 12 inches. where they impact the infiltrating area of the pond. Sand Ffte�Layer Sand filter layer has sediment deposits that exceeds Remove sediment and top layer 1/2-inch or the infiltration rate of the sand laye�is of sand,and replace in kind per less than 2 in/hr. specificaUon. Sediment S�ment accumulations in pond bottom that Removal of sediment nom pond Accumutation in exceeds 1/2-inch in depth or percolation test of the bottom. Pond Bottom pond indicates faality is only working at 909'0 of iYs design percolation rate. " Trash and Debris Accumulation that exceeds 1-CF per 1,000-SF of Trash and Debris removed from pond area. pond. InIeU Outlet Pipe InIeU oudet pipe clogged with sediment and/or No dogging or btockage in the debris material. inlet and outlet piping. ' Erosion Erosio�of ihe po�d's side sbpe and/or scouring of Slopes should be stabilized by the pond bottom,that exceeds 2inches,or where using proper erosion conVol poterrtial for continued erosio�is prevafent measures and repair methods. Sediment of Pond My part of these components that has settted 4- Slopes should be stabiGzed by Dike/Berm inches rn lower tlian the design elevaUon,or where using proper erosion control potential for c�ntinued erosion is prevalerrt. measures and repa+r methods. Rodc Window Rodc yvindow is dogged with sedimer�t. Window is free of sediment and debris. � Overflow Spillway Rock is missing and sal is exposed Reptace rocks to specifications. Infiltrafia�Vau1U Sediment Tanks:Sec�ment depth exoeeds 6-inches in depth. No sedment deposits in tank Tank Accumulation in bottom. Vault Trash and Debris Trash and debris acaanutated in tank,vault or Trash and debris removed irom Accumulation comecti�9 pipe.Indudes floatables and non- each faality. floatables. Access Cover Cove�cannot be opened or removed,especially by Cover repaired or replaced to Damaged/Not one person. proper working specifications or Working replaced. Tank or Vault Tank:Jants between tank secGons failing,such that Tank reptaced or repaired to Structure Damaged leakage occurs and.or material being washed design specificaGons. • Uuough into faclity;or maintenance/inspection person determines the tank is not structuratly sound. 9/1/98 1998 Surface Water Design Manual A-18 ' APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILI'IgS N0. 13-WATER QUALlTY FACILIIIES(CONTINUE� ' G.) Infiltration Ponds (Continuec� Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed IMiltration VaulU Tank or VauR Structural Vault:Cracks wider than 1/2-inch and any Tank replaced or repaired to Tank Damage evidence of soil partides entering the structure design specifications. th�ough the cracks,or maintenance inspection personnel determines that the vault is not structurally sound. - Access Ladder Damaged Ladder is corroded or deteriorated,not Ladder replaced or repaired to tunctioning properly,missing nmgs,has cracks specifications,and is safe to ' and/or misaligned. use as deteRnined by inspection personnel. 1498 Surface Water Design Manual 9/1/98 A-19 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAINED DRAINAGE FACILTITES , N0. 14-OIL CONTROL FACILITiES _A.) OiU Water Separators Maintenance Defect Condition When Maintenance is Needed Resutts Expected When Compone�t Maintenance is Performed. API Type OWS Monitoring Inspection of discharge water for obvious signs Effluent discharge from vauft of poor water quality. should be clear with out thick visible sheen. Sediment Accumulatio� Sediment depth in bottom of vault exceeds 6- No sediment deposits on vault inches in depth. bottom which would impede flow through the vault and separation efficiency. Trash and Debris Trash and debris accumulation in vault,or pipe Trash and debris removed from Accumulation inleV outlet,floatables and non-floatables. vault,and inleU outlet piping. Oil Accumula6on Od axumulations that exceed t-inch,at the Extract al from vauft by � surface of the water vactoring.Disposal in accordance with state and local n�les and regulations. Damaged Pipes IMet or outlet piping damaged or broken and in Pipe repaired or replaced. need of repair. - Access Cover Damaged/ Cover cannot be opened,one perso�cannot Cover repaired to proper Not Worldng open the oover,corrosioN defortnatio�of cover. working specificatioRs or . replaced. Vauft Structure Damage- Cracks wider than 1/2-inch and any evidence of Vauft replaced or repaired to Indudes Cracks in Walls soit partides entering the structure through the design specifica6ons. Bottom,Damage to cxacks,or maintenance/inspec:tion personnel Frame and/or Top Slab determines that the vault is not structurally sound. Baffles Baffles cortoding,craddng,warpirg and/or Repair or replace baffles to showing signs of failure as determined by specifications. maintenance/inspection person. Access Ladder Damaged Ladder is corroded or deteriorated,not Ladder replaced o�repaired and func6oning property,missing rungs,cracks,and meets specifications,and is misaligned. safe to use as detertnined by inspection persnrnel. Cracks wider than 1/2-inch at fhe joint of any No cxacks more tfian 1/4-inch inleV outlet pipe o�any evidence of soii particles wide at the joint of the inleU entering the vauft through the walls. oudet pipe. CPS-Type OWS MoriUoring Inspection of discharge water for obvious signs Effluent discharge from vauft of poor water quality. should be dear with no thick visible sheen. Sediment Aax�rtu�lation Sed'anent depth in bottom of vault exceeds E No sediment deposits on vauk inches in depth arxi!or visible signs of sediment bottom and plate media,which on plates. would impede flow through tt►e vault and separation efficiency. Trash and Debris Trash arxi debris acc�unulated in vault,or pipe Trash and debris removed from Accumulation inleU oudet,floatables and nort-floatables. vauft,and inlet/outlet piping. Oil Accumulation Oil accumulation that exceeds 1-inch at the Extract dl from vault by water surface. vactoring mettwds.C{ean coalescing plates by thoroughly rinsing and flushing.Should be no visible al depth on water. 9J1/98 1998 Surface Water Design Manual A-20 APPENDIX A MAINTENANCE STANDARDS FOR PRIVATELY MAINTAiNID DRAINAGE FACILTITES N0. 14-OIL CONTROL FACIUTIES(CONTJIYUED� � A.)OiV Water Separators(Continued) 'Aaintenance Defect Condition When Mai�tenance is Needed Results Expected When .:omponent Maintenance is Performed Damaged Coalescing Plate media broken,defortned,cradced and/or Replace that portion of inedia Piates showing signs of failure. � pack or entire plate padc depending on severity of failure. Damaged Pipes Inlet or outlet piping damaged or broken and in need Pipe repai�ed and or replaced. of repair. Baffles Baffles corroding,craddng,warping and/or showing Repair or replace baffles to signs of failure as determined by maintenance/ specifications. inspection person. Vauft SVucture Cracks wider than 1/2-inch and any evidence of soil Vault replaced or repaired to Damage-Indudes partides eMering the structure Uuough the cracks, design specifications. Cracks in Walls, or maintenance inspection personnel determines Bottom,Damage to that the vauft is not sVucturally sound. . Frame andJ or Top Slab Access Ladder Ladder is coRoded or deteriorated,not functioning Ladder replaced or repaired and Darnaged property,missing nmgs,cracks,and misaligned. meets specifications,and is safe to use as detertnined by . inspection personnel. Cradcs wider than 1r2-inch at the joint of any inleU No cracks more than 1/4-inch outlet pipe or any evidence of soil particles entering wide at the jo�t of the inleU the vautt through the walls. outlet pipe. g.)Catch Basin Inserts � daintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is Pertormed Catch Basin Sediment When sedment forms a cap over the insert media of No sediment cap on the insert � Accximulation the insert and!or unit media and iYs unit Trash and Debris Trash and debris accumulates on insert unit creating Trash and debris removed from Accumulation a blodcage!restriction. insert unit.Runoff freey flows into catch basin. Inspection Inspectio►�of ine�a insert is required. Effluent water from media insert is free of als and has no visible sheen. Media lnsert-Water Catch basin insert is saturated with water,which no Remove and replace media Saturated longer has the capacity to absorb. insert Media lnsert-Oil Media oil saturated due to petroleum spill that drains Remove and replace media I Saturated into catch basin. insert. General Regular interval replacement due to typical average Remove and replace media at life of inedia insert product. regular intervals,depending on insert product. 1998 Surface Water Design Manual 9/1/98 I A-21 l