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Home My WebLink About03386 - Technical Information Report R • V � Duvall 8 Short Plat � LUA-06-031 8 Lot Short Plat NE 10th Street and Duvall Avenue NE KC Tax Account #102305-9005 Technical Information Report Februaty 10, 2009 � Revised March 8, 2009 RE(;�� Revised April 8, 2009 QPR 2. � 2009 p��F�EVIEyy ' Prepared for ' Seattle Savings Bank Attn: Bruce Groom 190 Queen Anne Avenue North Suite 100 Seattle, WA 98019 ' �y�-�'' L. p O� \�IAS�r , r �' � �' y . Submitted by ��'� �`��' � �� ' � Offe Engineers, PLLC 1 2;��' ;� ww� Attn: Darrell Offe, P.E. �s�ONAL E�� 13932 SE 159�' Place sf � u Renton, WA 98058 �XPIRES .' ___.__�- ---- -.-. 338� Project Description The purpose of this report is to present a preliminary drainage and downstream review for the proposed Nguyen Property Short Plat project in accordance with the City of Renton requirements. The project is located at the northwest comer of NE 10�' Street and Duvall Avenue NE within the City iimits of Renton. The Nguyen Property Short Plat is a proposal to create 8 singie-family lots from an existing 1.11-acre parcel. The project is currently tax parcels number 102305-9Q05. There are no exisdng houses on the property. The parcel is bounded to the west by a proposed short plat called"Voung Short PIaY' currently on file at the C'ity of Renton, to the south and east are NE 10th Street and Dwall Avenue NE, respectfully. The property bo the north is undeveloped large lots with older homes and open fields. Review of Resouroes Critical Drainage Area Map-tl�e property is divided into two separats drainage basins • Maplewood Creek/ Cedar River/ Lake Washington Watershed • Honey Geek/ May Creek/ Lake Washington Watershed Flood plain/floodway(FEMA) Maps • There is no mapped floodplain in the immediate area per the available FEMA map. ' Sensitive Areas • Wetlands-There are no wetlands located on the property. • Str�ams and 100 Year Flood Plains-There are no apparent streams or floodplains that go through or abut the property. 'I • Erosion Hazard Areas-There are no landslide hazard areas for the properly. • Landslide Hazard Areas-There are designated sensitive slopes on and adjoining the property. • Seismic Hazard Areas-The area is not mapped as a seismic hazard area. i • Coal Mine Hazard Areas-The property does not appear to be located within a designed coalmine hazard area. - 2 - I:\BACK UP�2008 Deoemb�HP PAVIUON(C)\Offe Engineers\1 PROJECi5ulndy C�ir�es\��8�Nguyen Property\Coorespondenoe\Level One\lIR\sborm report.doc . U.S. Departrnent of Agricuiture, King County Soils Survey • The soils have been classified by Comerstone Geotechnical as Glaaal Tilis; a copy of the Geotechnical Report is attached as Appendix C. Row Control Application • The site is designated by the Caty of Renton as a Level Two detention standard. Water Quality Application • The project would provide Basic Water Quality control standards per the 2005 KCSWM Manual. Feld Inspection Offe Engineers has visited the site on several occasions. The most resent visit occurred the morning of January 31, 2006. The property is currently an open field with a shed located on the easteriy side. On the west, a gravel road exists along the proposed alignment of Chelan Avenue NE. The property is bound on the south and east by existing roads; NE 10"' Street and Duvalf Avenue NE. Open ditches currently convey the drainage along these roads. The property curreniiy discharges via sheet flow to the ditch along the west side of Dwall Avenue and sheet flows to the west on to the gravel road then into NE 10�' Street. There do not appear to be any drainage problems on the site or within the e�6sting open ditches. There is a downstr�eam open pond approximately 150 feet west of the site. In earlier discussions with the Gty of Renton Staff, this pond was built by the City to mitigate previous downstream drainage issues. Review of the 8 Core Requirements and 5 �al Requir+ements of the 2005 King County Surfaae Watier Design Manual OfFe Engineers has reviewed the Core and Specaal Requirements in Chapter 1 of the ' King County Surface Water Design Manual, and addresses each of the requirements as follows: Cor+e Re,quirement Na 1 —Disrhar,ge at Natvra/La��an The project will discharge via sheet flow into the existing open channel along Dwall Avenue NE and into the road conveyance system within NE 10"' Street. Cor�e Repui�ment No. 2—Of�ihe Ana/ysis Easberfy side -The property drains into an open ditch that flows both north and south along Dwall Avenue. The ditches do not show any signs of overtopping or capacity problems. Wesberly side—The NE 10"' conveyance system is 12 feet deep at the SW comer of the property. The system flows to the west an into the Gty open pond. Further review of this system will be necessary during construction documents to verify capacity or availability within the downstream pond. - 3 - I:�BAQC UP�2008 Decernber�HP_PAVILION(C�\Offe Engineers\i PROJECTS�Andy Carines\Dwall 8\Nguyen �rtY\�\Level One\TIR�Stonn repoitdoc I s Core Requir+ement No. 3—F/ow Conbv/ The proposed project will be required to provide control of the proposed houses and driveways. Level two detention controls are required by the City of Renton. Core Requirement No. 4—Conveyanc�e Sysl�em Conveyance systems of catch basins and pipe are proposed along the frontages of Duvall Ave., NE 10"' Street, and the proposed Chelan Ave. NE. This system will be sized to meet the 2005 KCSWM design standards. Core Re+quirement No, 5—Erosion and Sediment Contro/ A Temporary Erosion and Sediment Control Plan implementing the Best Management Practices will be designed as part of the final engineering plans for the project in accordance with �ty of Renton requirements. Core Requirement No, 6—Maint�enanae and Operabons The Maintenance and Operations Manual for the Nguyen Property Short Plat will be included in the Fnal Technical Information Report(TIR) as part of the final engineering design for the project. Core Re+quirement No. 7—Finanoa/Gaarant�e�es and Liabi/iiy The Fnancial Guarantees and Liabilities will be required prior to the project being finalized by the City of Renton. Core Re puirement No. 8— Wa�e�Qua/ity The proposed project will provide storm water quality treatment within the proposed vault meeting the 2005 KCSWM standards. Sp�eda/Re+quir+ement No. 1—Adopt�d Ar�a Sp�eaific Repuirements The project is located within the Cedar River Basin Plan and May Creek Basin Plan. Spersa/Repuirement No. Z—F/o�adp/ain/F/oadway D�e/ineation This requirement does not apply. Sp�e�cia/Requirement No. 3—F/oad Pint�e�dion Faoi/ities This requirement does not apply. Spe�aia/Reiquirement No. 4—Sourrae Conb�v/s This requirement does not apply. Specia/Requirement No, 5—Oi/Contro/ This requirement does not apply. - 4 - I:\BAQC UP�2008 Deoernber�HP_PAVILION(C�\Offe Ergineers\1 PROJECT'S�Ardy Carines\Dwall 8\Nguyen Property\Coorespondence\Level One\TIR\storm report.doc Appendix A Figures 1. Vicinity Map 2. Existing Site Topography 3. Proposed Site plan 'i il i - 5 - I:\BACK UP�2008 December�HP_PAVILION(C)\Offe Engineers\1 PROJECTS�Mdy Carir�es\Dwall 8\Nguyen Property\Coorespondence�Level One\TIR\storm report.doc 1 • � • I VICINITY MAP .� � � y�pY � sE g5TM � MAr � vn�y �� i �� s� � 9 � O+o /'` � �� W 2 W � � Q �� BIVp � � � �� , sE RENrpN _ �J � NE �2n� sT o W I� 2 � P ROJ ECT a NE ,oTM 5T LO CATI 0 N W Z z � � � � � Q < � NE � � �� j � ST O ; � A J j � � W S NE eni T � a � NE 4n� sr se izan� sr N I//C/N/rY MAP I SCALE.� NTS � _ � . i �„ � . �. i., � � '� ��- � � � , ,.. -, , , �,. �,,, •t �,,. 4.2 , � r a 4,� I i 0 �,^��o � �. � I I � — - ----•—�.� ` �� y �d u ,s �u e ��a. I I ,, ,�,, i s ,.•—' , � ' , �� , , I. �. ' �� , � . . � � �� 57Jf:29'3h t 2fJ8._�,.� i �/� \ � � � � i' � •_4' tl^.440EU l"ilf2'c FEf'Cr . ��:*,� � i � i i � � i � / ;%� � �� l � I ' / I � �..-.-� r, � �/' ��.,: ,r-�� I � /� �' ,'�+ ��.,_�-'"� � / ��, i f /° SI1Ep � �yf ��; i � I �� ,,-' ,,�'�/y / r�.__,,...._..�'-_ ,. � z i i� � `i =�7 ,/` � � � �, / j ', � � � � � i! ., �� r�'`-�-��\\ z i �;�� \ , w �;�� '�' � \\\ �l �� > i y `.. ' � � .��,:' �) s. .. .'� Q � -��: ��D � I� �i � i J ;� � .� �-�,,.�.,� K� ' J � �: , ; � �� I� i � ��i � � � Wir.a-:�a.3'+�.i: � y � � I il �r:�.s»,�,�", � '' �,:, ... , — , 1 �� . . � � I � � , , ----- � �� "i --/ /�% � �.._ .�� ' ' ` �� _�_ �, , � , , .,.._., � , ,, , � - l '�"'�'� __ _ ,� . 9 ....�.��'� � ^� -- ``t, _.... I " _ _.`L. _.. � — — — • — —•— —• --- —• -- I -- , _ ., _ �...— � N.E. 1 OTH STREET � — - ' " �,- ...�- >, t� � , ;�,,, ' , ,. � :IJG3 \yy��ir��u} �.. �� 'a ...�'. � 4 ?✓/ .;^ .. . I . ��/ :�x .��; �� ..:._��.�.., ,..�� l W l _ /p� � t§ d.� .� � f` � 4M � '�.�.-.J r Jp '' - �)l��,({ �tr � `✓ y'1. '�n r � �staw'�R �_..,�.I�A�+_.pyy-.."�� .::� � . �J`.�1�i) �'� Ew.a��SS �,e. � �.A � ,i� bs.... � '�!C u�QQ 1�,..iW.l U ` .� � �� '��, i�,'�� i t.� �$�.y , ��I.; ra_4T�71 A ��. 1 � .�� 1 I i � S 88'29'34" E 286.26' , 74.00' 90.00 20.00' 95.25' Z�� 4� 7� C �O� � � fV N J N 42, I '�' 'Sp0 SQ, F� a oo, �„0 SQ fEEt o g � a o ar, �i � 4�62 � I �0 Et cn � � � 6 Z$$ sa• F� � so.00� ss.�s' o � _ � o Q 0 � N z I r o � SQ F�� o ¢ � �-�� 2 FE� �o � � I W 74.00' � 4,5�� V �i 4�g6 Sn' �i � � I �� 3 � 90.00' � 95.13' w Q �n I a � � ► d- ��.� � o z g o n � sa• F�� N 'v a W � � 6'�� o � J c=� � I �M OS 6 ; �� 1 f�� a . I z , � � 30 sp� � o � 6.�� Sn M' � I �o ------_ _____��________s ��, � GRAPHICSCALE �g�'� 0 1 S 30 80 � 49.88' 20.00' 59.11' 42' � 1 /nch = 30 f�N N 88'29'34" W 286.05' � o s _ _ NORTHEAST 10TH STREET � — — — — — _ J Appendix B Detention Calcuiations (Levei 2) � Duvall 8 Short Plat LUA-06-031 REVISED 4-8-2009 Tota/Site Area 48,350 sq, fi: DEVELOPED 1,11 Acres Pre-Deve%pe�d Condition Impervious 0 sq. ft. PerVious 48,350 sq. ft. (Forest - Till) 1.11 Acres Deve%p�+d Condition Impervious 31,428 sq. ft. (48,350 * 65% coverage) 2,730 sq. ft. (public-road) NE lOth Street ** 0.78 Acres STA 4+75 - 3+45 1/2 street plus sidewalk (21'; Pen�ious 16,922 sq. ft. (48,350-31,428) 0,39 Acres 1.17 Acr�es Tota/Area Deve%p�ed ** - frontage improvements (otheerthan those accounted for) along Duvall Ave NE, NE lOth Street, and Chelan Avenue NE require saw-cut and removal of existing paved shoulder with replacement of new curb, gutter and sidewalk r - PRE-DEVELOPED CONDITIONS 2 , x Area J Till Forest 1.11 acres Till Pasture 0.00 acres Till Grass 0.00 acres Ouiwash Forest 0.00 acres Ouiwash Pasture 0.00 acres Outwash Grass 0.00 acres Wetland 0.0� acres Impervious 0.00 acres Total 1.11 acres Scale Factar: 1.OU Hourly Reduced Time Series: Pre-developed� ?> Compute Time Series I Modify User Input I File for computed Time Series [.TSFJ Flow Frequency Analysis Time Series File:pre-developed.tsf Project Locafion:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.078 2 2/09/O1 18:00 0.134 1 100.00 0.990 0.029 7 1/05/0216:00 0.078 2 25.00 0.960 0.071 3 2/28/03 3:00 0.071 3 10.00 0.900 0.008 8 3/24/04 19:00 0.067 4 5.00 0.800 0.040 6 1/OS/05 8:00 0.064 5 3.00 0.667 0.067 4 1/18/06 16:00 0.040 6 2.00 0.50a 0.064 5 11/24/06 4:00 0.029 7 1.30 0.231 0.134 1 1/09/08 6:00 0.008 8 1.10 0.091 Computed Peaks 0.116 50.00 0.980 Flow Frequency Analysis Time Series File:pre-dev='- ,�•� �-� Project Location:Sea-Ta. Developed Site Conditions ' � - � � � Area ? Till Farest 0.00 acres Till Pasture 0.00 acres Till Grass 0.39 acres Ouiwash Forest a•a� acres � Outwash Pasture 0.00 acres Ouiwash Grass O.OU acres 4+Yetland �.00 acres Imper►rious 0.78 acres Tatal 1.17 acres Scale Factor : 1.00 Hourly Reduced Time Series: Dev.tsf >?� Compute Time Series ____ __ __ _ __ _ __ _ __-� Modiiy User Input i File for computed Time Series [.TSFj F1ow Frequency Analysis Time Series File:dev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob fCFS) (CFS) Period 0.224 6 2/09/O1 2:00 0.451 1 100.00 0.990 G.185 8 1/OS/02 16:00 0.293 2 25.00 0.960 G.2o9 3 2/27/03 7:00 0.269 3 10.00 0.900 0.202 7 8/26/09 2:00 0.242 4 5.00 0.800 0.242 4 10/28/09 16:00 0.238 5 3.00 0.667 0.238 5 1/18/06 16:00 0.224 6 2.00 0.500 0.293 2 10/26/06 0:00 0.202 7 1.30 0.231 0.451 1 1/09/OB 6:00 0.185 8 1.10 0.091 Ccmputed Peaks 0.398 50.00 0.980 Interval Sizing: 2 Year Peak Flow = 0.04 cfs First Interval(50%of 2 Year) = 0.02 cfs Interval Size (50 Year-50%of 2 Year) = 0.116-0.02 = 0.096 cfs ? � 1 � 1 . X Time Series File is pre-de�eloped.tsf ?J Output File is Target.dur Type of Intervals �` Stage � Discharge Number of Intenrals 36 Interval Size 0.096� First Interval .02 User Specified intervals , Compute Flow Durations I �" means Intenral will be Computed Flow Duration from Time Series File:pre-developed.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS % % % 0.020 60771 99.105 99.105 0.895 0.895E-02 0.116 549 0.895 100.000 0.000 O.O00E+00 0.212 0 0.000 100.000 0.000 O.O00E+00 0.308 0 0.000 1�0.000 0.000 O.O00E+00 0.404 0 0.000 100.000 0.000 O.O00E+00 0.500 0 0.000 100.000 0.000 O.O00E+00 0.596 0 0.000 100.000 0.000 O.O00E+00 0.692 0 0.000 100.000 0.000 O.O00E+00 0.788 0 0.000 100.000 0.000 O.O00E+00 0.884 0 0.000 100.000 0.000 O.O00E+00 0.980 0 0.000 100.000 0.000 O.O00E+00 , 1.08 0 0.000 100.000 0.000 O.O00E+00 � 1.17 0 0.000 100.000 0.000 O.O00E+00 ' 1.27 0 0.000 100.000 0.000 O.O00E+00 1.36 0 0.000 100.000 0.000 O.O00E+00 1.46 0 0.000 100.000 0.000 O.O00E+00 1.56 0 0.000 100.000 0.000 O.O00E+00 , 1.65 0 0.000 100.000 0.000 O.O00E+00 1.75 0 0.000 100.000 0.000 O.O00E+00 1.84 0 0.000 100.000 0.000 O.O00E+00 1.94 0 0.000 100.000 0.000 O.O00E+00 2.04 0 0.000 100.000 0.000 O.O00E+00 2.13 0 0.000 100.000 0.000 O.O00E+00 2.23 0 0.000 100.000 0.000 O.O00E+00 2.32 0 0.000 100.000 0.000 O.O00E+00 2.42 0 0.000 100.000 0.000 O.O00E+00 '� 2.52 0 0.000 100.000 0.000 O.O00E+00 2.61 0 0.000 100.000 0.000 O.O0�E+00 2.71 0 0.000 100.000 0.000 O.O00E+00 2.80 0 0.000 100.000 0.000 O.OQOE+00 2.90 0 0.000 100.000 0.000 O.O00E+00 3.00 0 0.000 100.000 0.000 O.O00E+00 3.09 0 0.000 100.000 0.000 O.O00E+00 3.19 0 0.000 100.000 0.000 O.O00E+00 3.28 0 0.000 100.000 0.000 O.O00E+00 3.38 0 0.000 100.000 0.000 O.O00E+00 VAULT SIZING � � � ,� X Effective Storage Depth before Overflow[Ft) 11.90 ?� Elevation at 0 Stage [Ft] 419.1� Riser Head [Ft] 11.90 Riser Diameter[In] 12 Number of Orifices 2� Top of Riser t' Notched � Flat POINT of Compliance Setup I Edit Test HYDROGRAPH Parameters I Define RISER Orifices and Notch I Iterate then sa�e to Dutralt.rdf I This program can estimate design for at most 3 orifices Q(max) Orifice #1 = 4/3 of 50% of 2 Year = 4/3 * 0.02 = 0.026 cfs � • i - � �� Orifice Definitions ?J Orifice 2: Enter Height[FtJ � � � � Orifice 1: Enter Q-Max[CFSj 0.026 Entries Complete I Enter the stage elevation of orifice Detention Facilitv Desi_qn Retention/Detention Facility Type of Facility: Detention Vault Facility Length: 63.00 ft Facility Width: 18.00 ft Facility Area: 1139. sq. ft Effective Storage Depth: 12.00 ft Stage 0 Elevation: 419.10 ft Storage Volume: 13608. cu. ft Riser Head: 12.00 ft Riser Diameter: 12.00 inches Number of orifices: 2 Full Head Pipe Orifice 1k Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0.50 0.023 2 6.50 0.88 0.096 9.0 I Top Notch Weii: None Outflow Rating Curve: None Stage Elevaticn Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) {cfs) 0.00 419.10 0. 0.000 0.000 0.00 0.01 919.11 11. 0.000 0.001 0.00 0.02 919.12 23. 0.001 0.001 0.00 0.03 919.13 39. 0.001 0.001 0.00 0.09 919.14 95. 0.001 0.001 0.00 0.05 919.15 57. 0.001 0.001 0.00 0.25 419.35 289. 0.007 0.003 0.00 0.45 419.55 510. 0.012 0.005 O.OG 0.66 419.76 748. 0.017 0.005 O.GO 0.86 919.96 975. 0.022 0.006 0.00 1.06 920.16 1202. 0.028 0.007 O.C � 1.27 920.37 1440. 0.033 0.008 0.00 1.47 920.57 1667. 0.038 0.008 O.G 1.67 420.77 1694. 0.043 0.009 0.(' 1.86 420.98 2132. 0.099 0.009 0. 2.08 421.18 2359. 0.059 0.010 0. 2.28 921.38 2586. 0.059 0.010 0.� 2.49 921.59 2829. 0.065 0.011 0.' 2.69 421.79 3051. 0.070 0.011 0. 2.89 921.99 3277. 0.075 0.012 0. 3.10 422.20 3515. 0.081 0.012 0. 3.30 422.90 3742. 0.086 0.012 0. 3.50 422.60 3969. 0.091 0.013 0. 3.71 422.81 4207. 0.097 0.013 0.0 : 3.91 923.01 4934. 0.102 0.013 0.0:: 4.11 923.21 9661. 0.107 0.014 O.C.: 9.32 423.92 9899. 0.112 0.019 0.00 4.52 923.62 5126. 0.118 0.014 0.00 4.72 423.82 5353. 0.123 0.015 0.00 4.93 424.03 5591. 0.128 0.015 0.00 5.13 429.23 5817. 0.134 0.015 0.00 5.34 929.49 6056. 0.139 0.016 0.00 5.54 924.64 6282. 0.199 0.016 0.00 5.74 924.84 6509. 0.199 0.016 O.00 5.95 425.05 6797. 0.155 0.017 O.C� 6.15 425.25 6979. 0.160 0.017 O.C; 6.35 925.95 7201. 0.165 0.017 O.CC 6.50 425.60 7371. 0.169 0.017 O.OG Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 6.51 925.61 7382. 0.169 0.017 0.00 6.52 925.62 7394. 0.170 0.018 0.00 6.53 425.63 7405. 0.170 0.019 0.00 6.59 925.64 7916. 0.170 0.020 0.00 6.55 925.65 7928. 0.171 0.022 0.00 6.56 925.66 7939. 0.171 0.023 0.00 6.57 425.67 7450. 0.171 0.023 0.00 6.78 925.88 7689. 0.177 0.029 0.00 6.98 926.08 7915. 0.182 0.032 0.00 7.18 426.28 8192. 0.187 0.035 0.00 7.39 926.99 8380. 0.192 0.038 0.00 7.59 426.69 8607. 0.198 0.090 0.00 7.79 426.89 8834. 0.203 0.043 0.00 8.00 427.10 9072. 0.208 0.045 0.00 8.20 927.30 9299. 0.213 0.046 0.00 8.40 427.50 9526. 0.219 0.098 0.00 8.61 927.71 9764. 0.224 0.050 0.00 8.81 427.91 9991. 0.229 0.052 0.00 9.01 428.11 10217. 0.235 0.053 0.00 9.22 428.32 10955. 0.290 0.055 O.00 ' 9.42 428.52 10682. 0.295 0.056 O.OG 9.62 428.72 10909. 0.250 0.058 0.00 9.83 928.93 11197. 0.256 0.059 0.00 10.03 929.13 11374. 0.261 0.060 0.00 , 10.23 929.33 11601. 0.266 0.062 0.00 10.44 429.54 11839. 0.272 0.063 0.00 10.69 429.79 12066. 0.277 0.069 0.00 10.89 429.99 12293. 0.282 0.066 0.00 11.05 430.15 12531. 0.288 0.067 O.00 11.25 930.35 12758. 0.293 0.068 O.OQ 11.45 430.55 12984. 0.298 0.069 O.OG 11.66 430.76 13222. 0.304 0.070 O.OG 11.86 430.96 13499. 0.309 0.071 O.Ou 12.00 431.10 13608. 0.312 0.072 0.00 12.10 431.20 13721. 0.315 0.381 0.0�"; 12.20 431.30 13835. 0.318 0.944 0.�- 12.30 931.40 13948. 0.320 1.670 0.� 12.40 931.50 19062. 0.323 2.970 O.0 12.50 931.60 14175. 0.325 2.750 O,G:i 12.60 431.70 14286. 0.328 3.000 O.uU 12.70 431.60 19402. 0.331 3.240 0.00 12.80 931.90 19515. 0.333 3.460 0.00 12.90 432.00 14629. 0.336 3.660 0.00 13.00 932.10 19792. 0.338 3.860 0.00 Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-Ft', 1 0.45 0.13 0.26 12.06 931.16 13675. 0.319 2 0.22 ******* 0.07 11.63 930.73 13165. 0.303 3 0.23 ******* 0.06 10.33 929.93 11719. 0.269 4 0.27 ******* 0.06 9.35 928.95 10601. 0.243 5 0.24 **'**** 0.05 8.65 427.75 9812. 0.225 6 0.14 ******* 0.03 6.88 425.98 7806. 0.179 7 0.18 ******* 0.02 6.37 425.47 7229. 0.16E 8 0.20 ******* 0.01 4.88 423.98 5529. 0.12� Route Time Series through Facility Inflow Time Series File:dev.tsf Outflow Time Series File:RDOut Inflow/Outflow Analysis Peak Inflow Discharge: 0.451 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.255 CFS at 9:00 on Jan 9 in Year B Peak Reservoir Stage: 12.06 Ft Peak Reservoir Elev: 431.16 Ft Peak Reservoir Storage: 13675. Cu-�t . 0.314 Ac-Ft Flow Duration from Time Series File:rdout.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS 8 $ � 0.001 31686 51.673 51.673 48.327 0.483E+00 0.003 6898 11.249 62.922 37.078 0.371E+00 0.005 3233 5.272 68.195 31.805 0.318E+00 0.007 6353 10.360 78.555 21.445 0.214E+00 0.009 3978 6.987 85.042 19.958 0.150E+00 0.011 3642 5.939 90.982 9.018 0.902E-01 0.013 1603 2.940 93.922 6.078 0.608E-01 0.015 1650 2.691 96.613 3.387 0.339E-01 0.017 1093 1.782 98.395 1.605 0.160E-01 0.019 520 0.848 99.243 0.757 0.757E-02 0.021 17 0.028 99.271 0.729 0.729E-02 0.022 11 0.018 99.289 0.711 0.711E-02 0.024 45 0.073 99.362 0.638 0.638E-02 0.026 49 0.072 99.939 0.566 0.566E-02 0.028 38 0.062 99.996 0.504 0.509E-02 0.030 39 0.069 99.560 0.940 0.440E-02 0.032 28 0.096 99.605 0.395 0.395E-02 0.034 26 0.042 99.698 0.352 0.352E-02 0.036 15 0.024 99.672 0.328 0.328E-02 0.038 13 0.021 99.693 0.307 0.307E-02 0.040 16 0.026 99.720 0.280 0.280E-02 0.092 12 0.020 99.739 0.261 0.261E-02 0.049 10 0.016 99.755 0.245 0.295E-02 0.046 29 0.047 99.803 0.197 0.197E-02 0.048 21 0.034 99.837 0.163 0.163E-02 D.O50 16 0.026 99.863 0.137 0.137E-02 0.052 8 0.013 99.876 0.129 0.124E-02 0.059 12 0.020 99.896 0.109 0.104E-02 0.056 11 0.018 99.914 0.086 0.864E-03 0.057 7 0.011 99.925 0.075 0.750E-03 0.059 14 0.023 99.948 0.052 0.522E-03 0.061 8 0.013 99.961 0.039 0.391E-03 0.063 8 0.013 99.979 0.026 0.261E-03 0.065 3 0.005 99.979 0.021 0.212E-03 0.067 3 0.005 99.984 0.016 0.163E-03 0.069 5 0.008 99.992 0.008 0.815E-04 4 1 0� O o RDUut dur = � pr�deveioped dur • � r R � o � o � cfl � O O � �� I O I � � LL V «�.,; � m o �.; rn � o L V N Q M Q �r O � N i4 O O O0 .___ ___ O O `� O O O � 10-5 10-4 10-3 10 -� 10-� 10� Probability 6cceedence Duration Comparison Anayisis I Base File: pre-developed.tsf New File: rdout.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New �Change Probability Base New �Change 0.020 I 0.90E-02 0.73E-02 -18.9 � 0.90E-02 0.02a 0.017 -14.2 0.029 I 0.63E-02 0.64E-02 1.6 � 0.63E-02 0.024 0.025 0.9 0.029 I 0.49E-02 0.49E-02 -0.7 � 0.99E-02 0.029 0.029 -0.2 0.033 I 0.37E-02 0.38E-02 2.7 � 0.37E-02 0.033 0.034 0.3 0.038 � 0.28E-02 0.31E-02 9.8 � 0.28E-02 0.038 0.090 5.0 0.042 � 0.21E-02 0.26E-02 22.3 � 0.21E-02 0.092 0.095 7.3 0.047 � 0.15E-02 0.18E-02 19.4 ( 0.15E-02 0.097 0.049 3.9 0.051 � 0.11E-02 0.12E-02 15.2 � 0.11E-02 0.051 0.053 3.9 0.056 � 0.78E-03 0.82E-03 4.2 � 0.78E-03 0.056 0.057 1.3 0.060 � 0.99E-03 0.44E-03 0.0 � 0.94E-03 0.060 0.060 0.0 0.065 � 0.26E-03 0.21E-03 -18.8 � 0.26E-03 0.065 0.064 -1.9 0.069 � 0.15E-03 0.65E-04 -55.6 I 0.15E-03 0.069 0.067 -2.8 0.074 � 0.65E-04 O.00E+00 -100.0 I 0.65E-04 0.079 0.070 -5.7 0.078 I 0.16E-04 O.00E+00 -100.0 � 0.16E-04 0.078 0.070 -10.6 Maximum positive excursion = 0.004 cfs ( 9.7$) occurring at 0.091 cfs on the Base Data:pre-developed.tsf and at 0.095 cfs on the New Data:rdout.tsf Maximum negative excursion = 0.004 cfs (-19.6$) occurring at 0.021 cfs on the Base Data:pre-developed.tsf and at 0.017 cfs on the New Data:rdout.tsf ri I Wetpool Sizing Calculations I, Per 2005 King County Stormwater Management Manual ', Project Name: Duvall 8 Short Plat(revised 4-8-2009) Project Number: LUA-06-031 Facility Description: Wetpool storage Step 1: Identify required wetpool volume factor(f). f= 3 Per KCSWDM 6.4.1.1 Step 2: Determine rainfall (R)for the mean annual storm. R= 0.47 Per KCSWDM Fig. 6.4.1.A Step 3: Calculate runoff from the mean annual storm (V,)for the developed site. V�_ (0.9A;+ 0.25A,9 + 0.10A,�+0.01Ao)x (R/ 12) where: A; = Impervious Surface Area= 33,977 s.f. At9=Till Grass Area = 16,988 s.f. A� =Till Forest Area = 0 s.f. Ao =Outwash Area = 0 s.f. V�= 1,364 C.f. Step 4: Calculate required wetpool volume(Vb). Vb= fxV� Vb= 4,092 c.f.