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HomeMy WebLinkAbout03389 - Technical Information Report - Addendum #2 � • y;���� -''f- � ��� �- , -_ � — _ __ _----- (� Site Development Associates, LLC � 10117 fvtain Street;Bothe4t,NIA 98Qt f M or��e:az�a�ssss F�k-���aaa ss�� � Drainaqe Addendum #2 West Coast Subdivision Renton, Washington Prepared for: � . ` : � ' . CamWest Development, Inc. �,�,� d, MC �� .1�� Prepared By: � � � Site Development Associates, LLC .a � � 10117 Main Street p 39018 4 <c, Bothell, WA 98011 �ss°������ 425-486-6533 � . �o� �xP�R�s 08!30l �9� January 7, 2008 Job No. 108-002-04 � � � 338� . � SUMMARY OF CHANGES This document is intended as an Addendum to the approved Drainage Report for the West Coast Subdivision, which was prepared on May 17, 2007. The West Coast Subdivision project lies within the City of Renton, in the northeast quarter of Section 15, Township 23 North, Range 5 East, Willamette Meridian. The project originally proposed the subdivision of approximately 10.82 acres into 60 single- family residential housing lots. Since the approval of the May 17th report, the applicant has acquired an additional piece of adjacent property, which will be developed as a separate short-plat project at a later date. However, the applicant would like to demonstrate that the detention/treatment facilities being constructed for the West Coast project are sufficient to accommodate this future project as well. The new property adds approximately 0.46 acres of additional area to the project, and it is thought that it will be subdivided into three lots at some future time. As defined in the previous drainage report, the project contains three distinct drainage basins, which ultimately lie within the same threshold discharge area. A detention facility has been proposed within each basin, and each facility has been designed to roughly attenuate the flow from it's respective tributary basin. An analysis in the previous report demonstrated that the total site discharge met"Level Two"flow control standards for the threshold discharge area, as outlined in the 1998 King County Surface Water Design Manual (KCSWDM). The purpose of this addendum is to include the newly acquired properly into these calculations, and demonstrate that°Level Two" flow control standards can still be achieved. In order to meet these flow control standards, it was necessary to revise the design of the flow control structures in all three proposed detention vaults. The calculations provided at the end of this document show the required dimensions of the flow control structures, and these dimensions are also shown in the revised engineering drawings that accompany this report. The following pages include two exhibits, showing the existing and proposed conditions onsite. The exhibits include the newly acquired property. 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' � r m � L . ., ,,,.� r# ,. . -�-- \ i , ` � u `• � � � — ,� , -�_ y^A , " . ._.,. l � � ' . A i.rx�. �.�i�w. � ......�f. ,T,� „`I' �..IC;�'� � `�, �, � < �. �� , . 1 �'er a rsx s u r,�e�- i .�C m ( . rf , � .._,..... s c�x�i:,,. ��......, r \_ _..,._,,. .,�...__'. � {. � . Z R��� ' _�__`..._. ` ��-1 � � A ' ir ro.rcnkc �� � ' a -. . .. ._ � . L� ` � , war inox::�n �r`� ryw�>,:aiir � �.._ . .m , �I � W 0 �A' � ���� i � rr i+� I � i � I �� I � I i 0 I � � � I ao � ' I c , m � I � I\ I N i � i . . Additional Drainage Basin Area from new property= 0.46 Ac. Breakdown of New Propertv: Existing Lot Area = 0.30 Ac. (Assume 60% Impervious -from aerial photos) 0.18 Ac. Existing Pavement Area = 0.03 Ac. Existing Impervious Area Total = 0.21 Ac. Existing Pervious Area Total = 0.25 Ac. Developed Lot Area = 0.38 Ac. (Assume 75% Impervious-per previous assumption) 0.29 Ac. Developed Pavement Area = 0.09 Ac. Developed Impervious Area Total = 0.38 Ac. Developed Pervious Area Total = 0.09 Ac. Breakdown of Basin #2 Characteristics: ("previous"refers to 5/17/07 Drainage report) Existing Conditions: Previous Till Forest Area = 1.42 Ac. New Till Forest Area = 0.46 Ac. Total Till Forest Area = 1.88 Ac. Developed Conditions: Previous Till Grass Area = 026 Ac. New Till Grass Area = 0.09 Ac. Total Till Grass Area = 0.35 Ac. Previous Impervious Area = 1.16 Ac. New Impervious Area = 0.38 Ac. Total Impervious Area = 1.54 Ac. Page 1 of 2 . , Revised Input Parameters -Entire West Coast Site Per W ith 5/17/2007 New Re ort Pro e Existing Basin #1: Till Forest 4.23 4.23 Wetland 0.16 0.16 Existin Basin#2: Till Forest 1.42 1.88 Existin Basin #3: Till Forest 3.07 3.07 Total Existing Basin Area = 8.88 9.34 Developed Basin#1: Till Grass 2.26 2.26 Im ervious 1.97 1.97 Wetland Q.16 0.16 Developed Basin #2: Till Grass 0.26 0.35 Im ervious 1.16 1.54 Developed Basin#3: Till Grass 0.66 0.66 Im ervious 2.41 2.41 Total Developed Basin Area= 8.88 9.34 Page 2 of 2 . � Pre-Developed Conditions - Basin #1 _ ._ _ _ _ -- __ _ _ - -- - ? � � � � _�, Area- _ _--- ? � Till Forest 4•23 acres Till Pasture. 0.0� acres: Till Grass` 0.00 acres! Outwash Fnr�sf O.OU acres' Outwash Pasture' D.DO a�res{ Outvrash Grass� 0.�� �cres'; Wetland'' U.16 acres' impervious; O.QO acres, , __. ___ ----- ,-Total-_ _ - - : 4.39 acres`: Scale Factor : 1.00 Hourly Reduced Time Series: Predev-l.tsf » Compute Time Seri�� � Modif}r User Input � ;-----___ .__ _._am,_ . ----- __.�_ _-�--_ --- -- - -- ___ _�. File for computed Time Serie� [.TSF] Flow Frequency Analysis Time Series File:predev-l.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 0.284 2 2/09/O1 18:00 0.370 1 100.00 0.990 0.074 7 1/06/02 3:00 0.284 2 25.00 0.960 0.216 3 2/28/03 3:00 0.216 3 10.00 0.900 0.007 8 3/24/04 20:00 0.205 4 5.00 0.800 0.119 6 1/O5/O5 8:00 0.173 5 3.00 0.667 0.205 4 1/18/06 21:00 0.119 6 2.00 0.500 0.173 5 11/24/06 4:00 0.074 7 1.30 0.231 0.370 1 1/09/OS 9:00 0.007 8 1.10 0.091 Computed Peaks 0.341 50.00 0.980 . * Pre-Developed Conditions— Basin #2 _.�_ _ � � F� � � _� -Area ----------- ? Till Forest 1.88 acresl Till Pasture O.OD acres- ; Till Grass' 0.00 acres'; � Quiwash Farest U.00 acres � Outwash Pasture'' Q•aa acres Outwash Grass O.UO acresi � 4�etland: O.UO acres; � Impervinus; �.00 acresi ,-Tot�l-�- -- 1.88 acres Sc�le Fa�tor : 1.00 Hourly lReduced Time Seri�s: Predev-2.ts� » Compuxe Time Series � - -- _ _--_ ___ _— Modify User Inpu# � �--_---_ __--_ _____ _ ____ _ ___ —_ . . _ ---- File for Gomputed Time Series [.TSF] Flow Frequency Analysis Time Series File:predev-2.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 0.118 2 2/09/O1 18:00 0.151 1 100.00 0.990 0.032 7 1/06/02 3:00 0.118 2 25.00 0.960 0.088 4 2/28/03 3:00 0.091 3 10.00 0.900 0.003 8 3/24/04 20:00 0.088 4 5.00 0.800 0.052 6 1/O5/OS 8:00 0.077 5 3.00 0.667 0.091 3 1/18/06 20:00 0.052 6 2.00 0.500 0.077 5 11/24/06 4:00 0.032 7 1.30 0.231 0.151 1 1/09/08 9:00 0.003 8 1.10 0.091 Computed Peaks 0.14C 50.00 0.980 . � Pre-Developed Conditions- Basin #3 _ - - _ _ _.. _ _ --- - i .. � � � , � �-a� � r�x �-Area ? Till Forest 3.07 acres Till Pasture' 0.00 acres' Till Grass 0.00 acr�s' Outwash Fnrest U.00 acres; ; OUtwash Pasturel 0.00 acres�i � Outwash Grass' �.UO acres'� V+�etland Q•00 acres Impervious; 0.00 a�res _.__. _.__. ._---_._.. ;-Total--- ____ I3.07 acres _ .-----------___. Scale Factor : 1.�0 Hourly Reduced Time Series: Predev-3.ts� »' Compute Time Series � __ _ _ _ _ _- Modify User Inpu# � ,_____ _----____ _.____ —__ __ _- ---__. -----.______ --___ __------ _. ' File for compu#ed Time Series [.TSFJ Flow Frequency Analysis Time Series File:predev-3.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 0.194 2 2/09/O1 18:00 0.248 1 100.00 0.990 0.053 7 1/06/02 3:00 0.194 2 25.00 0.960 0.144 4 2/28/03 3:00 0.148 3 10.00 0.900 0.005 S 3/24/04 20:00 0.144 4 5.00 0.800 0.085 6 1/OS/OS 5:00 0.125 5 3.00 0.667 0.148 3 1/18/06 21:00 0.085 6 2.00 0.500 0.125 5 11/24/06 4:00 0.053 7 1.30 0.231 0.248 1 1/09/08 9:00 0.005 8 1.10 0.091 Computed Peaks 0.230 50.00 0.980 • � Developed Conditions— Basin #1 _ _- - _ - - - - . _ _ _v, __ _ � , � � � �Area------— ? � Till Forest� �.00 acres' Till Pasture� 0.00 acres Till Grass� 2-2fi acres, Ouiwash Forest' 0.00 acres Ouiwesh Pasturei O.OU acres', Outwash Grass� 0.0� acres Wetland! 0.16 acres, Impervious' 1.97 acres — --- ___ -Total -- -- A.39 acres' Scale Factor : 1.OU Hourly Reduced Time Series: Dev-1.tsf » Compute Time Series j - Modiiy User Input � -- -------------------._ __-- _ __�_._— __ - ----- File for computed Time Series [.TSF] Flow Frequency Analysis Time Series File:dev-l.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 0.702 5 2/09/O1 2:00 1.42 1 100.00 �.990 0.527 8 1/OS/02 16:00 0.846 2 25.00 0.960 0.846 2 2/27/03 7:00 0.774 3 10.00 0.900 0.533 7 8/26/04 2:00 0.718 4 5.00 0.800 0.650 6 10/28/04 16:00 0.702 5 3.00 0.667 0.718 4 1/18/06 16:00 0.650 6 2.00 0.500 0.774 3 10/26/06 0:00 0.533 7 1.30 0.231 1.42 1 1/09/OS 6:00 0.527 B 1.10 0.091 Computed Peaks 1.23 50.00 0.980 c � Developed Conditions— Basin #2 _ _ _ : _ . __ � , , �_ x . � - IArea--- - ? Till Foresti 0.00 acresi Till Pasture� a.QO �cres Till Grass� 0.35 acres i Outwash Forest� 0.00 acresi Ouiwash Pasture. �.00 acres� Outwash Grass! �.00 acres; V�l�tland" O.OQ acres'4 Impervious' 1.54 acres. � Total--- _- , 1.$9 acresl �_��_..---____. Scale Factor : 1.D0 Hourly Reduced Time Series: Dev-2.tsf y> Compute Time Series � _. __ Modify User Input � ' _ _ ___�_ _____v-..T__�_-- ___�.�_eez .___..___ __.___.. �._.—_ __ File far computed Time Senes [.TSF� Flow Frequency Analysis Time Series File:dev-2.tsf Project Location:Sea-Tac ---Annual Peak Flow Ratea--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Retum Prob (CFS) (CFS) Period 0.405 6 2/09/O1 2:00 0.802 1 100.00 0.990 0.345 8 1/O5/02 16:00 0.568 2 25.00 0.960 0.486 3 12/08/02 18:00 0.486 3 10.00 0.900 0.390 7 8/26/04 2:00 0.466 4 5.00 0.800 0.466 4 10/28/04 16:00 0.431 5 3.00 0.667 0.431 5 1/18/06 16:00 0.405 6 2.00 0.500 0.568 2 10/26/06 0:00 0.390 7 1.30 0.231 0.802 1 1/09/08 6:00 0.345 S 1.10 0.091 Computed Peaks 0.724 50.00 0.980 ; . r � Developed Conditions— Basin #3 --- - - _ __ _ _. . _. _ _ _ � , , . � '' ` ;-Area ------ ---; ?: Till Fnrestl U.00 acres; Till Pasture' D.00 acres: Till Grass� 0.66 acres' � Ouhvash Foresti 0.00 acres; OUiwash Pasture 0.00 acres 4uiwash Grass 0.00 acres; , 1+�letland O.OU acres' Impervious 2.41 acres' _ _-- _- - Total--_ _. _ 3.D7 acres: Scale Factor : 1.00 Hourly Reduced Time Series: Dev-3.ts� » Cnmpute Time �eries { __ _ . Modify User Inpu# � ;_�_--------.------- -�___..---__—__.___.__----- -____-----------,--_____ _ _- File for computed Time Series [.TSFJ Flow Frequency Analysis Time Series File:dev-3.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 0.644 6 2/09/O1 2:00 1.28 1 100.00 0.990 0.545 8 1/OS/02 16:00 0.892 2 25.00 0.960 0.770 3 12/OS/02 18:00 0.770 3 10.00 0.900 0.613 7 8/26/04 2:00 0.732 4 5.00 0.800 0.732 4 10/28/04 16:00 0.685 5 3.00 0.667 0.685 5 1/18/06 16:00 0.644 6 2.00 0.500 0.892 2 10/26/06 0:00 0.613 7 1.30 0.231 1.28 1 1/09/OB 6:00 0.545 8 1.10 0.091 Computed Peaks 1.15 50.00 0.980 Detention Vault Design - Basin #1 ov�xt�� FaciliriDefinition �E` y�Y'z� Type of Facility: Detention Vault Facility Length: 120.00 ft Facility Width: 37.00 ft �JC//K� �L�'v Facility Area: 4440. sq. ft ��� �.tr Effective Storage Depth: 12.00 ft �, Stage 0 Elevation: 394.25 ft ��f�Q�% Z Storage Volume: 53280. cu. ft Riser Head: 12.00 ft OvTC.Ctf Riser Diameter: 18.00 inches Number of orifices: 2 J��r� f��TE r�=;ps!rs Full Head Pipe Orifice # Height Diameter Discharge Diameter C�= 3�Z Is (ft? (in) (CFS) (in) OR�/�qS/= �y�� 1 0.00 0.75 0.053 2 7.50 2.00 0.230 4.0 Top Notch Weir: None Outflow Rating Curve: None Stape/StoranelDischars�e Perfortnance Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 394.25 0. D.000 0.000 0.00 0.01 394.26 44. 0.001 0.001 0.00 0.02 394.27 89. 0.002 0.002 0.00 0.03 394.28 133. 0.003 0.003 0.00 0.04 394.29 178. 0.004 0.003 0.00 0.05 394.30 222. 0.005 0.004 0.00 0.06 394.31 266. 0.006 0.004 0.00 0.27 394.52 1199. 0.028 0.008 0. 0.47 394.72 2087. 0.048 0.010 0. 0.67 394.92 2975. 0.068 0.013 0. 0.88 395.13 3907. 0.090 0.014 0. 1.08 395.33 4795. 0.110 0.016 0. 1.28 395.53 5683. 0.130 0.017 0. : 1.49 395.74 6616. 0.152 0.019 0.= 1.69 395.94 7504. 0.172 0.020 O.0 1.89 396.14 8392. 0.193 0.021 O.Cu 2.10 396.35 9324. 0.214 0.022 O.GG 2.30 396.55 10212. 0.234 0.023 0.00 2.50 396.75 11100. 0.255 0.024 0.00 2.71 396.96 12032. 0.276 0.025 0.00 2.91 397.16 12920. 0.297 0.026 0.00 3.11 397.36 13808. 0.317 0.027 0.00 3.32 397.57 14741. 0.338 0.028 0.00 3.52 397.77 15629. 0.359 0.029 0.00 3.72 397.97 16517. 0.379 0.029 0.00 3.93 398.18 17449. 0.401 0.030 0.00 4.13 398.38 18337. 0.421 0.031 0.00 4.33 398.58 19225. 0.441 0.032 0.00 4.54 398.79 20158. 0.463 0.032 0.00 4.74 398.99 21046. 0.483 0.033 0.00 4.94 399.19 21934. 0.504 0.034 0.00 5.15 399.40 22866. 0.525 0.035 0.00 5.35 399.60 23754. 0.545 0.035 0.00 5.55 399.80 24642. 0.566 0.036 0.00 5.76 400.01 25574. 0.587 0.037 0.00 5.96 400.21 26462. 0.607 0.037 0.00 6.16 400.41 27350. 0.628 0.038 0.00 6.37 400.62 28283. 0.649 0.039 0.00 6.57 400.82 29171. 0.670 0.039 0.00 6.77 401.02 30059. 0.690 0.040 0.00 6.98 401.23 30991. 0.711 0.040 0.00 r t Duration Comparison Malvsis Duration Comparison Anaylsis Base File: predev-l.tsf New File: rdout-l.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- ---------Check of Tolerance------- Cutoff Base New �Change Probability Base New �Change 0.060 � 0.94E-02 0.75E-02 -20.9 � 0.94fi-02 0.060 0.044 -25.5 0.077 � 0.62E-02 0.63E-02 1.8 � 0.628-02 0.077 0.080 3.5 0.094 � 0.48E-02 O.S1E-02 5.4 � 0.465-02 0.094 0.096 1.7 0.111 � 0.35E-02 0.36E-02 1.4 � 0.358-02 0.111 0.112 0.5 0.128 � 0.27E-02 0.28E-02 3.6 � 0.27&-02 0.128 0.131 2.3 0.146 � 0.20E-02 0.24E-02 18.7 I 0.20E-02 0.146 0.156 7.1 0.163 � 0.13E-02 0.18E-02 31.7 � 0.13E-02 0.163 0.182 11.6 0.180 � 0.88E-03 0.14E-02 53.7 � O.BBE-03 0.180 0.205 13.7 0.197 � O.SSE-03 0.98E-03 76.5 � O.SSfi-03 0.197 0.226 14.4 0.214 � 0.338-03 0.77E-03 135.0 � 0.335-03 0.214 0.241 12.5 0.232 � 0.20E-03 0.42E-03 116.7 � 0.208-03 0.232 0.260 12.3 0.249 � 0.13E-03 0.26E-03 100.0 � 0.13B-03 0.249 0.267 7.1 0.266 � 0.82E-04 0.13E-03 60.0 � 0.82E-04 0.266 0.272 2.2 0.283 � 0.16E-04 O.00E+00 -100.0 � 0.16E-04 0.283 0.276 -2.5 Maximum positive excursion = 0.030 cfs ( 15.9�) occurring at 0.185 cfs on the Base Data:predev-l.tsf and at 0.215 cfs on the New Data:rdout-l.tsf Maximum negative excursion = 0.015 cfs (-25.5$) occurring at 0.060 cfs on the Base Data:predev-l.tsf and at 0.044 cfs on the New Data:rdout-l.tsf . N M o RDGut-1_dur � Target-1 dur • N R o �� N O � � �� N N O � U a� � a� � o t u N � N � � � O O � � 00 U'� p -^-C•_��. � �J`�. O 0 � 10-5 10-4 10-3 10 -2 10-� 10� Probability Exceedence 'i i f Detention Vault Design - Basin #2 Facilitv Definition OV�.�fto�� Type of Facility: Detention Vault EL y/b.s 0 Facility Length: 100.00 ft Facility Width: 19.50 ft Facility Area: 1950. sq. ft Effective Storage Depth: 12.50 ft /� Stage 0 Elevation: 398.00 ft ie��f��'f� Storage Volume: 24375. cu. ft �6= Y�.Z� Riser Head: 12.50 ft • '� Riser Diameter: 18.00 inches Dit�fKf�� �y Number of orifices: 2 Full Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0.63 0.037 ��T/,�f� 2 7.25 1.25 0.097 4.0 m Top Notch Weir: None ���3 370•� Outflow Rating Curve: None �arr+�.• Pur� c�= 3t�•oe . StaaelStorapelDischar�e Performance ���$�= s�g Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 398.00 0. 0.000 0.000 0.00 0.01 398.01 20. 0.000 0.001 0.00 0.02 398.02 39. 0.001 0.001 0.00 0.03 398.03 59. 0.001 0.002 0.00 0.04 398.04 78. 0.002 0.002 0.00 0.05 398.05 98. 0.002 0.002 0.00 0.26 398.26 507. 0.012 0.005 0.00 0.48 398.48 936. 0.021 0.007 0.00 0.69 398.69 1346. 0.031 0.009 0.00 0.90 398.90 1755. 0.040 0.010 0.00 1.11 399.11 2165. 0.050 0.011 0.00 1.32 399.32 2574. 0.059 0.012 0.00 1.54 399.54 3003. 0.069 0.013 0.00 1.75 399.75 3413. 0.078 0.014 0.00 1.96 399.96 3822. 0.088 0.015 0.00 2.17 400.17 4232. 0.097 0.016 0.00 2.38 400.38 4641. 0.107 0.016 0.00 2.59 400.59 5051. 0.116 0.017 0.00 2.81 400.81 5480. 0.126 0.018 0.00 3.02 401.02 5889. 0.135 0.018 0.00 3.23 401.23 6299. 0.145 0.019 0.00 3.44 401.44 6708. 0.154 0.020 0.00 3.65 401.65 7118. 0.163 0.020 0.00 3.87 401.87 7547. 0.173 0.021 0.00 4.08 402.08 7956. 0.183 0.021 0.00 4.29 402.29 8366. 0.192 0.022 0.00 4.50 402.50 8775. 0.201 0.022 0.00 4.71 402.71 9185. 0.211 0.023 0.00 4.92 402.92 9594. 0.220 0.024 0.00 5.14 403.14 10023. 0.230 0.024 0.00 5.35 403.35 10433. 0.239 0.025 0.00 5.56 403.56 10842. 0.249 0.025 0.00 5.77 403.77 11252. 0.258 0.025 0.00 5.98 403.98 11661. 0.268 0.026 0.00 6.20 404.20 12090. 0.278 0.026 0.00 6.41 404.41 12500. 0.287 0.027 0.00 6.62 404.62 12909. 0.296 0.027 0.00 6.83 404.83 13319. 0.306 0.028 0.00 7.04 405.04 13728. 0.315 0.028 0.00 7.25 405.25 14138. 0.325 0.029 0.00 7.26 405.26 14157. 0.325 0.029 0.00 r t Stape/Storaae/Discharae Performance(continued) Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 7.28 405.28 14196. 0.326 0.030 0.00 7.29 405.29 14216. 0.326 0.031 0.00 7.30 405.30 14235. 0.327 0.034 0.00 7.32 405.32 14274. 0.328 0.037 0.00 7.33 405.33 14294. 0.328 0.040 0.00 7.34 405.34 14313. 0.329 0.042 0.00 7.35 405.35 14333. 0_329 0.042 0.00 7.57 405.57 14762. 0.339 0.053 0.00 7.78 405.76 15171. 0.348 0.060 0.00 7.99 405.99 15581. 0.358 0.066 0.00 8.20 406.20 15990. 0.367 0.072 0.00 8.41 406.41 16400. 0.376 0.076 0.00 8.63 406.63 16829. 0.386 0.081 0.00 8.84 406.84 17238. 0.396 0.085 0.00 9.05 407.05 17648. 0.405 0.089 0.00 9.26 407.26 18057. 0.415 0.092 0.00 9.47 407.47 18467. 0.424 0.096 0.00 9.68 407.68 18876. 0.433 0.099 0.00 9.90 407.90 19305. 0.443 0.102 0.00 10.11 408.11 19715. 0.453 0.105 0.00 10.32 408.32 20124. 0.462 0.108 0.00 10.53 408.53 20534. 0.471 0.111 0.00 10.74 408.74 20943. 0.481 0.114 0.00 10.96 408.96 21372. 0.491 0.117 0.00 11.17 409.17 21782. 0.500 0.119 0.00 11.38 409.38 22191. 0.509 0.122 0.00 11.59 409.59 22601. 0.519 0.124 0.00 11.80 409.80 23010. 0.528 0.127 0.00 12.02 410.02 23439. 0.538 0.129 0.00 12.23 410.23 23849. 0.547 0.132 0.00 12.44 410.44 24258. 0.557 0.134 0.00 12.50 410.50 24375. 0.560 0.135 0.00 12.60 410.60 24570. 0.564 0.598 0.00 12.70 410.70 24765. 0.569 1.440 0.00 12.80 • 410.80 24960. 0.573 2.540 0.00 12.90 410.90 25155. 0.577 3.830 0.00 13.00 411.00 25350. 0.582 5.300 0.00 13.10 411.10 25545. 0.586 6.730 0.00 13.20 411.20 25740. 0.591 7.260 0.00 13.30 411.30 25935. 0.595 7.750 0.00 13.40 411.40 26130. 0.600 8.220 0.00 13.50 411.50 26325. 0.604 8.650 0.00 13.60 411.60 26520. 0.609 9.0'70 0.00 13.70 411.70 26715. 0.613 9.470 0.00 13.80 411.80 26910. 0.618 9.850 0.00 13.90 411.90 27105. 0.622 10.220 0.00 14.00 412.00 27300. 0.627 10.570 0.00 14.10 412.10 27495. 0.631 10.910 0.00 14.20 412.20 27690. 0.636 11.250 0.00 14.30 412.30 27885. 0.640 11.570 0.00 14.40 412.40 28080. 0.645 11.880 0.00 Sta�elStora�e/Discharste Performance at Sis�nificant Storm Events Hyd Inflow Outflow Peak Storage Target Calc Stage Elev (Cu-Ft) (Ac-rt) 1 0.80 *�***** 0.69 12.61 410.61 24592. 0.565 2 0.57 ******* 0.05 7.61 405.61 14841. 0.341 3 0.49 0.09 0.02 4.54 402.54 8859. 0.203 4 0.47 *;'**** 0.02 3.95 401.95 7704. 0.177 S 0.43 ******'� 0.09 9.38 407.38 18287. 0.420 6 0_40 ******* 0.13 12.22 410.22 23837. 0.547 7 0.39 ******* 0.03 5.90 403.90 11501. 0.264 8 0.34 *Y;**�* 0.03 7.18 405.18 14010. 0.322 4 � KCRTS Routins�instructions Route Time Series through Facility Inflow Time Series File:dev-2.tsf Outflow Time Series File:RDOut-2 Inflow/Outflow Analysis Peak Inflow Discharge: 0.802 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.696 CFS at 9:00 on Jan 9 in Year 8 Peak Reservoir Stage: 12.61 Ft Peak Reservoir Elev: 410.61 Ft Peak Reservoir Storage: 24592. G�-Ft . 0.565 AC-Ft Flow Duration Analvsis Flow Duration from Time Series File:rdout-2.tsf Cutoff Count Frequency CDF Fixceedence_Probability CFS � � � 0.002 29933 48.814 48.814 51.186 0.512E+00 0.006 7928 12.929 61.743 38.257 0.383E+00 0.009 5747 9.372 71.115 28.885 0.289E+00 0.013 6490 9.932 81.047 18.953 0.190E+00 0.017 4895 7.983 89.030 10.970 0.110B+00 0.021 2661 4.340 93.369 6.631 0.663E-01 0.024 1886 3.076 96.445 3.555 0.356E-01 0.028 1603 2.614 99.059 0.941 0.941E-02 0.032 218 0.356 99.415 0.585 O.SSSE-02 0.035 16 0.026 99.441 0.559 0.559E-02 0.039 11 0.018 99.459 0.541 0.541E-02 0.043 19 0.031 99.490 0.510 O.S10E-02 0.047 26 0.042 99.532 0.468 0.468E-02 0.050 30 0.049 99.581 0.419 0.419E-02 0.054 26 0.042 99.623 0.377 0.377E-02 0.058 26 0.042 99.666 0.334 0.334E-02 0.061 18 0.029 99.695 0.305 0.305E-02 0.065 13 0.021 99.716 0.284 0.284E-02 0.069 12 0.020 99.736 0.264 0.264E-02 0.073 16 0.026 99.762 0.238 0.238E-02 0.076 13 0.021 99.783 0.217 0.217E-02 0.080 12 0.020 99.803 0.197 0.197E-02 0.084 14 0.023 99.826 0.174 0.174E-02 0.088 16 0.026 99.852 0.148 0.148E-02 0.091 14 0.023 99.674 0.126 0.126E-02 0.095 9 0.015 99.689 0.111 0.111E-02 0.099 9 0.015 99.904 0.096 0.962Fs-03 0.102 12 0.020 99.923 0.077 0.766fi-03 0.106 11 0.018 99.941 0.059 0.587E-03 0.110 6 0.010 99.951 0.049 0.489E-03 0.114 5 0.008 99.959 0.041 0.4088-03 0.117 5 0.008 99.967 0.033 0.326E-03 0.121 8 0.013 99.980 0.020 0.196E-03 0.125 2 0.003 99.984 0.016 0.163E-03 0.128 4 0.007 99.990 0.010 0.978E-04 0.132 3 0.005 99.995 0.005 0.489E-04 [ • Duration Comparison Analvsis Duration Comparison Anaylsis Base File: predev-2.tsf New File: rdout-2.tsf Cutoff Units: Discharge in CFS -----Fraction of Time----- - --Check of Tolerance------- Cutoff Base New �Change Probability Base New $Change 0.026 � 0.94E-02 0.23E-01 143.2 � 0.94E-02 0.026 0.026 8.4 0.033 � 0.63E-02 0.58E-02 -S.5 � 0.63E-02 0.033 0.029 -12.1 0.040 I O.SOE-02 0.54E-02 9.2 � O.SOE-02 0.040 0.044 10.3 0.047 � 0.37E-02 0.45E-02 22.4 � 0.37E-02 0.047 0.054 15.0 0.054 I 0.28E-02 0.37E-02 31.0 � 0.28E-02 0.054 0.066 20.8 0.062 � 0.22E-02 0.30E-02 38.5 � 0.22E-02 0.062 0.076 23.7 0.069 I 0.15E-02 0.27E-02 82.2 � 0.15E-02 0.069 0.088 28.5 0.076 I O.10E-02 0.22E-02 121.0 � O.10E-02 0.076 0.098 29.0 0.083 � 0.62E-03 0.18E-02 197.4 � 0.62E-03 0.083 0.105 26.4 0.090 � 0.34E-03 0.14E-02 295.2 � 0.34E-03 0.090 0.117 29.6 0.097 � 0.23E-03 O.10E-02 357.1 � 0.23E-03 0.097 0.121 24.3 , 0.104 � 0.16E-03 0.65E-03 300.0 � 0.16E-03 0.104 0.125 19.8 ' 0.111 I 0.11E-03 0.46E-03 300.0 � 0.11E-03 0.111 0.127 14.6 0.118 I 0.16E-04 0.29E-03 1700.0 � 0.16E-04 0.118 0.133 12.4 Maacimum positive excursion = 0.027 cfs ( 30.7�) occurring at 0.088 cfs on the Base Data:predev-2.tsf and at 0.115 cfs on the New Data:rdout-2.tsf Maximum negative excursion = 0.004 cfs (-12.7�) occurring at 0.035 cfs on the Base Data:predev-2.tsf ard at 0.030 cfs on the New Data:rdout-2.tsf R sfl T � �C�Ui-�.�Lif �` Target-2.dur + � 4 R �. N a � :. . . .. :_�. Q �^ O � � U o w � rn o Q o , t ci N � � O O � O O 00 N 6 O � O �^ O � 0 `> I 10 �5 10-° 10�3 10 -2 10 -� 10° Probability Exceedence a • Detention Vault Design- Basin #3 Facilitv Definition ����� 6c; ro�.so Type of Facility: Detention Vault Facility Length: 354.70 ft Facility Width: 20.00 ft Facility Area: 7094. sq. ft fiffective Storage Depth: 7.25 ft ` Stage 0 Elevation: 394.25 ft �/AC� C�BO"� Storage Volume: 51432. cu. ft �� 399 's Riser Head: 7.25 ft � �� Riser Diameter: 12.00 inches 0����� �� Number of orificea: 2 F'ull Head Pipe Orifice # Height Diameter Discharge Diameter (ft) (in) (CFS) (in) 1 0.00 0.88 0.056 ���i� 2 5.50 1.13 0.045 4.0 ��3yy,ts' Top Notch Weir: Noae Outflow Rating Curve: None 8�. .�.�:t f�= 39t.2S Stas�elStoras�e/Dischar�e Performance ������; ?�h Stage Blevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 0.00 394.25 0. 0.000 0.000 0.00 0.01 394.26 71. 0.002 0.002 0.00 0.02 394.27 142. 0.003 0.003 0.00 0.03 394.28 213. 0.005 0.003 0.00 0.04 394.29 284. 0.007 0.004 0.00 0.05 394.30 355. 0.008 0.005 0.00 0.06 394.31 426. 0.010 0.005 0.00 0.07 394.32 497. 0.011 0.006 0.00 0.20 394.45 1419. 0.033 0.009 0.00 0.32 394.57 2270. 0.052 0.012 0.00 0.44 394.69 3121. 0.072 0.014 0.00 0.56 394.81 3973. 0.091 0.016 0.00 0.69 394.94 4895. 0.112 0.017 0.00 0.81 395.06 5746. 0.132 0.019 0.00 0.93 395.18 6597. 0.151 0.020 0.00 1.06 395.31 7520. 0.173 0.021 0.00 1.18 395.43 8371. 0.192 0.023 0.00 1.30 395.55 9222. 0.212 0.024 0.00 1.42 395.67 10073. 0.231 0.025 0.00 1.55 395.80 10996. 0.252 0.026 0.00 1.67 395.92 11847. 0.272 0.027 0.00 1.79 396.04 12698. 0.292 0.028 0.00 1.92 396.17 13620. 0.313 0.029 0.00 2.04 396.29 14472. 0.332 0.030 0.00 2.16 396.41 15323. 0.352 0.031 0.00 2.28 396.53 16174. 0.371 0.031 0.00 2.41 396.66 17097. 0.392 0.032 0.00 2.53 396.78 17948. 0.412 0.033 0.00 2.65 396.90 18799. 0.432 0.034 0.00 2.78 397.03 19721. 0.453 0.035 0.00 2.90 397.15 20573. 0.472 0.035 0.00 3.02 397.27 21424. 0.492 0.036 0.00 3.14 397.39 22275. 0.511 0.037 0.00 3.27 397.52 23197. 0.533 0.038 0.00 3.39 397.64 24049. 0.552 0.038 0.00 3.51 397.76 24900. 0.572 0.039 0.00 3.64 397.89 25822. 0.593 0.040 0.00 3.76 398.01 26673. 0.612 0.040 0.00 3.88 398.13 27525. 0.632 0.041 0.00 4.01 398.26 28447. 0.653 0.042 0.00 4.13 398.38 29298. 0.673 0.042 0.00 Stas�e/Storas�e/Dischar�e Performance(continued) Stage Elevation Storage Discharge Percolation (ft) (ft) (cu. ft) (ac-ft) (cfs) (cfs) 4.25 398.50 30150. 0.692 0.043 0.00 4.37 398.62 31001. 0.712 0.043 0.00 4.50 398.75 31923. 0_733 0.044 0.00 4.62 398.87 32774. 0.752 0.045 0.00 4.74 398.99 33626. 0.772 0.095 0.00 4.87 399.12 34548. 0.793 0.046 0.00 4.99 399.24 35399. 0.813 0.046 0.00 5.11 399.36 36250. 0.832 0.047 0.00 5.23 399.48 37102. 0.852 0.048 0.00 5.36 399.61 38024. 0.873 0.048 0.00 5.48 399.73 38875. 0.892 0.049 0.00 5.50 399.75 39017. 0.896 0.049 0.00 5.51 399.76 39088. 0.897 0.049 0.00 5.52 399.77 39159. 0.899 0.050 0.00 5.54 399.79 39301. 0.902 0.051 0.00 5.55 399.80 39372. 0.904 0.053 0.00 5.56 399.81 39443. 0.905 0.055 0.00 5.57 399.82 39514. 0.907 0.058 0.00 5.58 399.83 39585. 0.909 0.059 0.00 5.59 399.84 39655. 0.910 0.060 0.00 5.72 399.97 40578. 0.932 0.066 0.00 5.84 400.09 41429. 0.951 0.070 0.00 5.96 400.21 42280. 0.971 0.074 0.00 6.09 400.34 43202. 0.992 0.077 0.00 6.21 400.46 44054. 1.011 0.081 0.00 6.33 400.58 44905. 1.031 0.084 0.00 6.45 400.70 45756. 1.050 0.086 0.00 6.58 400.83 46679. 1.072 0.089 0.00 6.70 400.95 47530. 1.091 0.091 0.00 6.82 401.07 48381. 1.111 0.094 0.00 6.95 401.20 49303. 1.132 0.096 0.00 7.07 401.32 50155. 1.151 0.098 0.00 7.19 401.44 51006. 1.171 0.100 0.00 7.25 401.50 51432. 1.181 0.101 0.00 7.35 401.60 52141. 1.197 0.411 0.00 7.45 401.70 52850. 1.213 0.976 0.00 7.55 401.80 53560. 1.230 1.710 0.00 7.65 401.90 54269. 1.246 2.500 0.00 7.75 402.00 54979. 1.262 2.780 0.00 ?.85 402.10 55688. 1.278 3.040 0.00 7.95 402.20 56397. 1.295 3.280 0.00 8.05 402.30 57107. 1.311 3.500 0.00 8.15 402.40 57816. 1.327 3.700 0.00 8.25 402.50 58526. 1.344 3.900 0.00 8.35 402.60 59235. 1.360 4.080 0.00 8.45 402.70 59944. 1.376 4.260 0.00 8.55 402.80 60654. 1.392 4.430 0.00 8.65 402.90 61363. 1.409 4.600 0.00 8.75 403.00 62073. 1.425 4.760 0.00 8.85 403.10 62782. 1.441 4.910 0.00 8.95 403.20 63491. 1.458 5.060 0.00 9.05 403.30 64201. 1.474 5.200 0.00 9.15 403.40 64910. 1.490 5.340 0.00 Stas�e/Stora4elDischars�e Performance at Si�nificant Storm Events Hyd Inflow Outflow Peak Storage Stage Elev (Cu-Ft) (Ac-Ft) 1 1.28 0.10 7.22 401.47 51218. 1.176 2 0.89 0.04 3.55 397.80 25177. 0.578 3 0.77 0.03 2.14 396.39 15172. 0.348 4 0.73 0.03 1.80 396.05 12748. 0.293 5 0.69 0.04 4.52 398.77 32036. 0.735 6 0.64 0.09 6.72 400.97 47684. 1.095 7 0.61 0.03 2.70 396.95 19171. 0.440 8 0.�4 0.04 3.88 39B.13 27509. 0.632 . . Point of Comnliance Discharae at Sianificant Storm Events Hyd R/D Facility Tributary Reservoir POC Outflow Outflow Inflow Inflow Target Calc 1 0.10 0.95 ******** *****�* 1.03 2 0.04 0.09 ;*•***** ******* 0.13 3 0.03 0.05 ******** 0.04 0.08 4 0.03 0.05 ******** ******* 0.07 5 0.04 0.18 **�***** ******* 0.23 6 0.09 0.41 **�***** ******* 0.50 7 0.03 0.05 *****'*' *****'�* 0.09 8 0.04 0.12 +******* ******* 0.16 KCRTS Routins�Instructions Route Time Series through Facility Inflow Time Series File:dev-3.tsf Outflow Time Series File:RDOut-3 POC Time Series File:DSOut-Site Inflow/Outflow Analysis Peak Inflow Discharge: 1.28 CFS at 6:00 on Jan 9 in Year 8 Peak Outflow Discharge: 0.100 CFS at 17:00 on Jan 9 in Year 8 Peak Reservoir Stage: 7.22 Ft Peak Reservoir Elev: 401.47 Ft Peak Reservoir Storage: 51218. Cu-Ft . 1.176 AC-Ft Add Time Series:rdout-1+2.tsf Peak Summed Discharge: 1.03 CFS at 9:00 on Jan 9 in Year 8 Point of Compliance File:DSOut-Site.tsf Designer's Note: Notice that Vauit#1 and Vault#2 did not meet duration-matching requirements. However,the discharge from those two vaults has been added together and modeled as a bypass flow for Vault#3. A point-of-compliance analysis has been performed for Vault#3 showing that the combined outflow from all three vaults meets the duration-matching criteria for the entire site. 1 1 Flow Duration Analvsis for Detention Vault#3 Flow Duration from Time Series File:rdout-3.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS � � � 0.001 25381 41.391 41.391 58.609 0.586E+00 0.004 3557 5.801 47.192 52.808 0.528E+00 0.007 3392 5.532 52.723 47.277 0.473E+00 0.009 4275 6.972 59.695 40.305 0.403E+00 0.012 2984 4.866 64.561 35.439 0.354E+00 0.015 3214 5.241 69.803 30.197 0.302E+00 0.018 3585 5.846 75.649 24.351 0.244E+00 0.020 3250 5.300 80.949 19.051 0.191E+00 0.023 2030 3.311 84.260 15.740 0.157E+00 0.026 2504 4.083 88.343 11.657 0.117E+00 0.028 1707 2.784 91.127 8.873 0.887E-01 0.031 1366 2.228 93.355 6.645 0.665E-01 ' 0.034 851 1.388 94.742 5.258 0.526E-01 0.037 1043 1.701 96.443 3.557 0.356E-01 0.039 850 1.386 97.829 2.171 0.217E-01 0.042 459 0.749 98.578 1.422 0.142E-01 0.045 290 0.473 99.051 0.949 0.949E-02 0.047 267 0.435 99.486 0.514 0.514E-02 0.050 144 0.235 99.721 0.279 0.279E-02 0.053 13 0.021 99.742 0.258 0.258E-02 0.055 7 0.011 99.754 0.246 0.246E-02 0.058 6 0.010 99.764 0.236 0.236E-02 0.061 6 0.010 99.773 0.227 0.227E-02 0.064 10 0.016 99.790 0.210 0.210E-02 0.066 11 0.018 99.808 0.192 0.192E-02 0.069 15 0.024 99.832 0.168 0.168E-02 0.072 7 0.011 99.843 0.157 0.157E-02 0.074 7 0.011 99.855 0.145 0.145E-02 0.077 9 0.015 99.870 0.130 0.130E-02 0.080 6 0.010 99.879 0.121 0.121E-02 0.083 8 0.013 99.892 0.108 O.lOBE-02 0.065 9 0.015 99.907 0.093 4.930E-03 0.088 13 0.021 99.928 0.072 0.718E-03 0.091 13 0.021 99.949 0.051 0.506E-�3 0.093 9 0.015 99.964 0.036 0.359E-03 0.096 16 0.026 99.990 0.010 0.978E-04 t � Flow Duration Analvsis for Entire Site Flow Duration from Time Series File:dsout-site.tsf Cutoff Count Frequency CDF Exceedence_Probability CFS � � � 0.007 26831 43.756 43.756 56.244 0.562fi+00 0.022 7936 12.942 56.698 43.302 0.433fi+00 0.036 6709 10.941 67.639 32.361 0.324E+00 0.050 6053 9.871 77.510 22.490 0.225E+00 0.064 5015 8.176 85.688 14.312 0.143E+00 0.079 3692 6.021 91.709 8.291 0.829E-01 0.093 2116 3.451 95.160 4.840 0.484E-01 0.107 1838 2.997 98.157 1.843 0.184E-01 0.121 563 0.918 99.075 0.925 0.925E-02 0.135 106 0.173 99.248 0.752 0.752E-02 �' 0.150 54 0.088 99.336 0.664 0.664E-02 0.164 50 0.082 99.418 0.582 0.582E-02 0.178 55 0.090 99.507 0.492 0.492E-02 0.192 42 0.068 99.576 0.424 0.424E-02 0.207 26 0.042 99.618 0.382 0.382E-02 0.221 24 0.039 99.658 0.342 0.342E-02 0.235 33 0.054 99.711 0.289 0.289B-02 0.249 15 0.024 99.736 0.264 0.264E-02 0.264 13 0.021 99.757 0.243 0.243E-02 0.278 15 0.024 99.781 0.219 0.219E-02 0.292 19 0.031 99.812 0.188 0.188E-02 0.306 11 0.018 99.830 0.170 0.1705-02 0.320 B 0.013 99.843 0.157 0.157E-02 0.335 9 0.015 99.858 0.142 0.1428-02 0.349 13 0.021 99.879 0.121 0.1215-02 0.363 8 0.013 99.892 0.108 0.108E-02 0.377 14 0.023 99.915 0.085 0.848B-03 0.392 7 0.011 99.927 0.073 0.7345-03 0.406 5 0.008 99.935 0.065 0.652E-03 0.420 11 0.018 99.953 0.047 0.473E-03 0.434 9 0.015 99.967 0.033 0.326E-03 0.448 3 0.005 99.972 0.028 0.277E-03 0.463 3 0.005 99.977 0.023 0.228E-03 0.477 3 0.005 99.982 0.018 0.179E-03 0.491 5 0.008 99.990 0.010 0.978E-04 0.505 4 0.007 99.997 0.003 0.326E-04 ♦ � Duration Comparison Analvsis for Entire Site Duration Comparison Anaylsis Base File: predev-site.tsf New File: dsout-site.tsf G�toff Units: Discharge in CFS ! -----Fraction of Time----- ---------Check of Tolerance------- C�toff Base New �Change Probability Base New �Change 0.127 � 0.96fi-02 0.84E-02 -12.5 � 0.96E-02 0.127 0.120 -5.7 0.163 � 0.64E-02 0.59E-02 -8.2 � 0.64E-02 0.163 0.155 -4.7 0.199 � 0.495-02 0.41E-02 -17.2 � 0.49E-02 0.199 0.178 -10.5 0.235 � 0.37fi-02 0.29E-02 -21.3 � 0.37E-02 0.235 0.212 -9.7 0.271 � 0.28E-02 0.23E-02 -19.1 � 0.28E-02 0.271 0.239 -11.8 0.307 � 0.21E-02 0.17E-02 -20.0 � 0.21E-02 0.307 0.281 -8.4 0.343 � 0.14E-02 0.13E-02 -6.9 � 0.14E-02 0.343 0.336 -2.0 0.379 � 0.95E-03 0.83E-03 -12.1 � 0.95B-03 0.379 0.372 -1.8 0.415 � 0.59E-03 0.54E-03 -8.3 I 0.59B-03 0.415 0.412 -0.7 0.451 � 0.29E-03 0.28E-03 -5.6 � 0.29fi-03 0.451 0.446 -1.0 0.487 � 0.20E-03 0.13E-03 -33.3 � 0.20B-03 0.487 0.473 -2.8 0.523 I 0.15E-03 O.00E+00 -100.0 I 0.15E-03 0.523 0.482 -7.7 0.559 � 0.98E-04 O.00E+00 -100.0 � 0.98fi-04 0.559 0.494 -11.7 0.595 � 0.16E-04 O.00E+00 -100.0 � 0.16E-04 0.595 0.506 -14.9 Maximum positive excursion = 0.001 cfs ( 0.3�) occurring at 0.400 cfs on the Base Data:predev-site.tsf and at 0.401 cfs on the New Data:dsout-site.tsf Maximum negative excursion = 0.089 cfs (-14.9�) I occurring at 0.595 cfs on the Sase Data:predev-site.tsf and at 0.506 cfs on the New Data:dsout-site.tsf 326E-04 � � r c RGOtit-3 dur o DSOut-Site dur- • Target-Site.dur • co 0 �i O Vl ,� ��. � u � d � � t , u r� y O � N O � R o k� 00 ��Z�,��,.L� o �`" � o � �'�'7'r�rT �"��c'`'�. 10-5 10-4 10 -3 10-2 10-� 10° Probability Exceedence a� • k Wetpool Sizing Calculations Per 1998 King County Stormwater Management Manual Project Name: Westcoast Project Number: 108-004-06 Facility Description: Basin#3 Water Quality Step 1: Identify required wetpool volume factor(f). f= 3 Per KCSW DM 6.4.1.1 Step 2: Determine rainfall (R)for the mean annual storm. R= 0.47 Per KCSW DM Fig. 6.4.1.A Step 3: Calculate runoff from the mean annual storm (V�)for the developed site. V�= (0.9A;+ 0.25A�y +0.10Aff+0.01Aa)x(R/ 12) where: A; = Impervious Surface Area = 105,071 s.f. A,9 =Till Grass Area = 28,750 s.f. A� =Till Forest Area = 0 s.f. Ao =Outwash Area = 0 s.f. V,= 3,985 c.f. Step 4: Calculate required wetpool volume(Vb). ub= f XV� Vb= 11,956 c.f. Step 5: Determine Wetpool Dimensions. Provided Length = 108 ft. Provided W idth = 20 ft. Provided Depth = 6 ft. Provided Volume= 12,960 cu.ft. � . � -- � M � Wetpool Sizing Summary Basin Basin Basin Threshold #1 #2 #3 Discharge Area Required Wetpool 12,704 c.f. 7,542 c.f. 11,956 c.f. 32,202 c.f. Storage Volume Provided Wetpool 17,760 c.f. 5,850 c.f. 12,960 c.f. 36,570 c.f. Storage Volume