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Home My WebLink AboutL94P0017 i 1 i 1 - i ., RECEIVE MAY 2 21995 LAND USE Scrt�fa�; J 1 i ! OSTERGAARD ROBINSON &ASSOC. INC. CONSULTING ENGINEERS 1 TROVITSKY PARK LEVEL 3 DOWNSTREAM ANALYSIS RECEIVED MAY 2 21995 LAND USE SEk'v,� S \R,p, OST�A� OPT!� w��►��o ti s 17174 Eg �W STES NAL D(PIRE9 1/16/9 7 -_ I BRL 95-128 5-19-95 TROVITSKY PARK TABLE OF CONTENTS i I. Introduction IL East Basin 1. Downstream Analysis 2. Conclusions and recommendations 3. Basin Summary a) 2 year b) 10 year c) 100 year 4. Results of Backwater Analysis 5. East Basin Area Breakdown a) Off-site East Basin Map 6. East Basin Storm Routing & Backwater Analysis Pre- Developed Conditions 7. East Basin Storm Routing & Backwater Analysis Developed Conditions III. West Basins 1. Downstream Analysis 2. Conclusions and Recommendations 3. West Basin Area Breakdown a) Off-site West Basin Map 4. Basin Summary a) 2 year b) 10 year c) 100 year 5. West Basin Storm Routing & Backwater Analysis Pre- Developed Conditions 6. West Basin Storm Routing & Backwater Analysis Developed Conditions IV. Attachments 1. Surface Water Management Estimate of 100 year Flood Stage of Lake Desire 2. Plan Sheets a) East Basin Downstream Analysis b) West Basin Downstream Analysis 3. Profile Sheets a) East Basin Downstream Analysis b) West Basin Downstream Analysis INTRODUCTION The enclosed Level 3 downstream analysis is based in part upon the Level 1 downstream analysis as prepared by Subdivision Management, Inc. dated February 25, 1994 and data contained in the Preliminary Technical Information Report prepared by Pacific Engineering Design, Inc. dated December 22, 1994. Pre-developed and post-developed storm water hydrographs were modeled using the SBUH method. Computer softwear entitled "Waterworks" as prepared by Ingenious Systems, Inc. was utilized for this purpose. Storm water conveyance facilities were analyzed under uniform flow conditions utilizing Manning's Equation. A hydraulic gradeline was then developed by the direct step backwater method. 1 EAST BASIN TROVITSKY PARK DOWNSTREAM ANALYSIS EAST DRAINAGE BASIN East Drainage Basin: Runoff from the site collects in a roadside ditch along the east property line of 172nd Avenue SE. Stormwater is directed north in this roadside ditch approximately 380' to an existing 12" concrete pipe flowing east across 172nd Avenue SE. Neighbors in the area have described water ponding at this culvert and on occasions water has overtopped the road. Runoff discharge from this culvert is conveyed in a vegetated ditch approximately 900 feet to Lake Desire. There are two existing driveway culverts along this ditch. Local residences have expressed concerns of flooding along this course attributed to high lake levels and allegedly as a result of development of Petrovisky Park. Conclusions and Recommendations: As a result of the enclosed analysis it was determined that the downstream conveyance system was under capacity during storm events equal to or greater than the 10 year-24 hour event { under existing conditions. Mitigation options include: 1. Replacement of culverts C1 & C2 together with regrading ditches, 2. Construction of a new tightline conveyance from the west side of 172nd Avenue SE to the lake, or 3. Increased detention with restrictive release rates onsite. The third option is met by virtue of the P-suffix conditions which govern design within the Lake Desire Drainage Basin. The pre-developed 10 year-24 hour runoff rates (the storm event which is the inception of flooding of the downstream system) will not be exceeded for all events up to and including the 100 year storm event. The enclosed analysis which is based upon data contained in the Preliminary Technical Information Report prepared by Pacific Engineering Design, Inc. dated December 22, 1994, demonstrates that the development of Trovitsky park will result in a reduction of peak flows to the downstream system. While this will not correct the existing problem it will improve upon this condition. RESULTS OF BACKWATER ANALYSIS CULVERT Cl STAGE ELEVATION STORM EVENT PRE-DEVELOPED POST-DEVELOPED 2 YR - 24 HR 497.16 496.76 10 YR - 24 HR 501.59 498.43 100 YR - 24 HR 514.71 504.41 CULVERT C2 STAGE ELEVATION STORM EVENT PRE-DEVELOPED POST-DEVELOPED 2 YR - 24 HR 495.98 495.53 10 YR - 24 HR 498.68 497.11 100 YR - 24 HR 505.12 500.05 CULVERT C3 STAGE ELEVATION STORM EVENT PRE-DEVELOPED POST-DEVELOPED 2 YR - 24 HR 492.48 492.44 10 YR - 24 HR 493.37 493.26 100 YR - 24 HR 494.35 494.02 EAST BASIN AREA BREAKDOWN & OVERLAND FLOW DISTANCES BASIN AREA OVERLAND FLOW DISTANCE AND SLOPE (fc REACH OA 0.59 AC 100' @ 6.0% OB 0.81 AC 200' @ 3.5% OC 3.10 AC 300' @ 7.6% 400' @5.7% OD 6.83 AC 300' @ 4.0% 550' @ 1.82% OE 0.69 AC 300' @ 1.67% OF 0.37 AC 150' @ 0.8% OG 46.85 AC 300' @ 3.3% 500' @ 8.0% 1500' @ 0.67% DE 24.39 AC 100' @ 1.0% 1800' @ 2.5% I PE 24.39 AC 300' @ 1.33% 410' @ 1.46% 160' @ 2.5% 150' @ 4.0% 480' @7.5% Note: OA = Off site Basin A (Typical) DE = Developed Condition East Basin (Typical) PE = Pre-developed Condition East Basin (Typical) ® Jm- r �` \�\�ov'. / �"'�. / i' / AWL aka., i �\ . / • ..... _+. \\ ....._ l� .. _. fir/ _ / 4. ••- pnnse r . Rees / m flonse I roes \ \ INK itoe { 550 fill I I h pi ► i s �' � > Jf � Qj �. .501 AD _... i;:� / ..- .•sue` , t9 �•�� •v .. ;; • R -o � c � �i �r r c a� C ,. ,�.I I l O D.. '• i. I J � � r t 3 L I.i K E N T S,C N O DISTRI T _ r PIER I �` ��) j ,.1� r 'e `M.'.�y' �' Uenio nos ._ /< \` ti •� q..1m^��: .MIN 1' `_�i. _ / = +-...... ... �' �.�._..r"'� -- _.. 11�`WII•lral• MM.•IM. C 'r ;M. L •�:....�. Arc. 597 i •� r 1'Uwtlr � SCHOOL 4.3 .AC As � '+'\'t"�` I �� ......•.... :(Inns 2 YEAR o PACIRcENGINEERING DESIGN INC. o CIVIL ENGINEERING AND PLANNING CONSULTANTS RECEIVED August 8 , 1995 AUG 141995 Mr . Mike Ramano 0,qu coUNl y Subdivision Management , Inc . LAND USE SERVICES 16031 - 119th Place NE Bothell , Washington 98011 Re : Trovitsky Park U11ry pook1 Project # 93092 Revised Preliminary Wetpond Design Mike . Per your request , we have revised our conceptual design for the wetpond serving the east portion of the project (portion draining to Lake Desire) . The revised design responds to the May 1 , 1995 Surface Water Management memo which imposed stringent stormwater detention and water quality requirements on that portion of the project tributary to Lake Desire . DETENTION (Live Storage) Our initial design met the flow control requirements cited in the memo, but provided only the standard 30 percent volumetric factor of safety . In the revised design , the total volume of live storage has been increased to provide a 40 percent volumetric factor of safety . Req ' d live storage = 1 . 4 x 107 ,405 CF = 150 , 367 CF (was 139 , 627 CF) Live Storage prov ' d = 150 , 450 CF in three cells WATER QUALITY In accordance with the memo ' s requirement for the project to meet Lake Desire Water Quality Management Plan recommendations , the wetpond design has been revised to provide a permanent pool (dead storage) volume equal to 4 . 5 times the volume of runoff from the mean annual storm. This is a 4 . 5-fold increase in dead storage over our initial design . Mean annual storm runoff volume = 1/3 of the 2yr storm volume 2yr storm volume = 67 , 533 CF 1/3 2yr storm volume = 22 , 511 CF Req ' d Dead Storage = 4 . 5 x 22 , 511 CF = 101 , 300 CF Dead Storage prov ' d = 106 , 700 CF in three cells GREG A. DIENER P.E. JOHN R. NEWELL P.E. RICHARD A. TOMKINS P.E. 130 ANDOVER PARK EAST, SUITE 300. SEATTLE, WASHINGTON eel ee FAX/431-7J7S 206/431-7970 Mike Ramano p 2 . Trovitsky Park In addition to increased permanent pool volume , the memo cites a requirement to provide a treatment train to meet AKART standards for total phosphorus (TP ) removal . A sand filter facility is specified for a part of this train although only very preliminary design criteria is currently available from Surface Water Management . My review of the "Peek-Preview Draft" of the proposed new Water Quality Chapter of the SWM design manual indicates that a Sand Filter Vault may be an appropriate facility for this project . The sand filter would be placed downstream of the wetpond in train with a grass- lined biofilter swale . In our revised design , a 30 ' ± wide by 260 ' ± long area has been set aside to accommodate the bioswale / sand filter treatment train . I have reviewed the revised plat map prepared by your office . The expanded Tract B area appears to be of adequate size to accommodate the new wetpond and treatment train requirements . A sketch of our revised pond concept is attached . If you have any questions , please give me a call . Sincerely , PACIFIC ENGINEERING DESIGN , INC. Richard Tomkins , P . E . att : Revised Wetpond Exhibit , Calculations S3SZ sic at t Tw � 44 S,s I 536 2 m IN4702 4PUNIPI sz' W A4L (T , A j 5446 0 C SSG- � � --------- - ,� 54Z Y W " 48 v 550 s 55z vi co Tv KtF- A E ss 556 _. ._..__ _ 2U WA m SS I �` 8 7-012A 6f OFAC 6TV10,4164FI- WF7FG)IVP 70 N.W3, D = 6 Z-/V& 5 7-6)P,-A GE REO 'D 5 04 0 0 C,F, :54�� Tv 547, 0:5 0 = 4, 0,51 wo,f,A 4-71,W) SOEACE 41 VF 5 702A6E C91-L- 4q7 Z5*,F 148soo. 794 90, c5a- Z- OZ37 S,F 74 5Z S.F / ,76300 , 5D/00 1 c/-.-,1,e- ZZ37 5-F 36400 - d-O 900, /() 6 ^700 150450. 7:= 00/,300 REV)) ( 1504009S��P 774 50//50400 92,5�o IN CIE 4, �,FA16TAI -'1'11Z)71-1 EA 7/0 Z. = 260' 74- /30 -,V-/ kV(A VC) — 6 S -t-6 Z V4) z' G 2,75 Llw .= 5401&7, 75 -r 5, 60 y' ...�'R. IM'Rl1/1M1— J e1R..1EFA! NL\�RwMVI,'�7M.� / ,01 141 72_ "_' �- b(O ' 1 , 1 �• . •, y R ,fr"v*�. N'ff�••1 `,� '� fog =P £S/.'" •-"!�v n �Q ��i --- 1 �v !a, 1' all h �' .ems,. n \ Y "'��, •, , 1 ol ,ll ' tJl' !'� � C• moo•--� B �„ �• 3 fi �� / �� ,�- .�' �( a P �� ` 0 y y�,r I Dy✓A-r t R.."�`i� .. .. .• '1 'ya �s I '1 1 5;19/95 Osterc}Marc# Robinson & Assoc. Inc. pate l TROV I TS4 Y P ARr::: EAST BASIN SUMMARY 2YR , 10YR & 100YR .," _____---__--•------------==-==BASIN-SUMMARY BASIN I B: OB NAME: 2YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 0. 81 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2. 00 inches AREA. . . 0. 75 Acres TIME INTERVAL. . . . „ 10.00 min CN. . . . . 81 .00 TIME OF CONC. . . . . : 37. 81 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 06 Acres CN. . . . . 98.00 0 TcReach -• Sheet L: 200.00 ns:c_a„ 4i_00 p2yr: 2.00 s:0. Ca._5 PEAK RATE: 0. 06 cfs VOL: 0. 05 Ac-ft TIME: 490 rain BASIN NAIY 2Y 24 R SBUH METHODOLOGY TOTAL AREA. . . . . . . . 0. 37 Acres BASEFLOWS: 0. 00 cfs_ RAINFALL TYPE. . . . . USER 1 PERVIOUS AREA PRECIPITATION. . . . .. 2.00 inches AREA. . . 0. 37 Acres TIME INTERVAL. . . . . 10.00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 54. 20 min IMPERVIOUS AREA ABSTRACTION C'OEFF: 0.20 AREA. . : 0. 00 Acres CN. . . . . 98. 00 0 TcReach -• Sheet L: 150. 00 nssc a„ 4ii00 p2yr: 2. 00 s:0. ra080 PEAK RATE; 0.02 cfs VOL: 0. 02 Ac-f t TIME: 20 min 1 BASIN! ID: BE NAME: 2YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 24. 39 Acres BASEFLOWS: 0. 00 cfs; RAINFALL TYPE. .. . . : USER PERVIOUS AREA PRECIPITATION. . . . . 2.00 inches AREA. . . 12. 98 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . . 86. 00 TIME OF CONC. . . . . : 20.87 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 11 . 41 Acres CN. . . . . 98. 00 TcReach - Sheet L: 100. 00 ns: 0. 1 00 p2yr: 2.00 s: c_a.ta100 TcReach - Channel L: 1800. 00 k:c: 4^. 00 s:Ca, 0250 PEAK RATE: 6. 31 cfs VOL: 2.61 Ac--f t TIME: 480 min S� 5/19/95 OstergaarU Robinson & Assoc. Inc. page 2 TROVITSKY PART: EAST BASIN SUMMARY BASIN SUMMARY BASIN IB: OA NAME: 2YR 24HR SBUH METHODOLOGY TOTAL_ AREA. . . . . . . . 0. 59 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . . 2. 00 inches AREA. . . 0. 59 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 17. 50 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres CN. . . . : 98. 00 TcReach - Sheet L: 100.00 ns: 0.4000 p yr: 2. 00 s:0. 0600 PEAK RATE: 0. 05►5 cfs VOL: 0.03 Ac-f t TIME: 480 min (BASIN ID: OB NAME: 2YR 241-R SBUH METHODOLOGY HOI:OL OGY TOTAL AREA. . . . . . . : U. 81 Acres BASEFLOWS: 0. 00 cfs RAINFALL_ TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . . 2. 00 inches AREA. . . 0. 75 Acres TIME INTERVAL. . . . : 10. 00 miry CN. . . . : 81 . 0o TIME OF CONC. . . . . : 37. 81 81 min IMPERVIOUS AREA ,►l ABSTRACTION COEFF: 0. 20 AREA. . : 0.06 Acres CN. . . . . 98. 00 TcReach - Sheet L: 200. 00 ns: 0. 4000 p2yr: 2. 00 s„0. 0350 PEAK RATE: 0. 06 cts VOL_: 0. 05 Ac--ft TIME: 490 Amin BASIN I D: OC NAME: '.'_YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 3. 10 Acres BASEFLOWS: 0. 00 :-, s RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . . 2.00 inches AREA. . . 2. 98 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 4:3. 93 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 12 Acres CN. . . . . 98. 00 TcReach -- Sheet L: 300.00 ns: 0. 4000 p2yr: 2. 00 s:0.0760 TcReach - Shallow L: 400. 00 ks: 5.00 s:O. 0570 PEAK RATE: 0. 21 cfs VOL.: 0. 17 Ac•-ft TIME: 490 min I 5/19/95 Ostergaard Robinson & Assoc. Inc. page TROYITSKY PARK EAST BASIN SUMMARY BASIN-SUMMARY BASIN ID: OD NAME: 2YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 6. 93 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2. 00 inches AREA. . . 6. 59 Acres TIME INTERVAL. . . . . 10. 00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 63. 16 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 0. 24 Acres CN. . . . . 98. 00 TcReach - Sheet L_: 300. 00 ns:0. 4000 p2yr: 2. 00 s: 0. 0400 TcReach - Shallow L: 550.00 ks: 5.00 s: 0. 0182 PEAK RATE: 0. 37 cfs VOL: 0. 37 Ac-ft TIME: 520 min BASIN ID: OE NAME: 2YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 0. 69 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . . 2.00 inches AREA. . . 0. 69 Acres TIME INTERVAL. . . .. . 10.00 min CN. . . . . B1 „ 00 y TIME OF CONC. . . . . : 70. 31 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 2() AREA. . 0. 00 Acres C:N. . . . . 98. 00 TcReach - :sheet L: 300. 00 ns:0. 4000 p2yr: 2. 00 s: 0. 0167 PEAK RATE::: 0. 03 cfs VOL.: 0. 03 Ac-ft TIME: 520 min BASIN ID: OF NAME: 2YR 24HR SBUH METHODOLOGY TOTAL_ AREA. . . . . . . . 0.37 Acres BASEFLOWS: 0. 00 cfs RAINFALL_ 'TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2. 00 inches AREA. . . 0. 37 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81 . 00 TIME OF CONC. . . . .. : 54. 20 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres CN. . . . . 98.00 TcReach - Sheet L: 150.00 ns:0. 4000 p2yr: 2. 00 s:0. 0080 PEAK RATE: 0.. 02 cfs VOL: 0. 02 Ac-ft TIME: 520 min } 5/19/95 Ostergaard Robinson & Assoc. inn. page .} TROV I !_SKY PARv EAST BASIN SUMMARY 2YR , 10YR & 1 i 0YR BASIN SUMMARY BASIN ID: OG NAME: 2YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 46. 85 Acres BASEFLOWS: 0. 00 0 cfs RAINFALL TYPE. . . . : UtS'ER 1 PERVIOUS AREA PRECIPITATION. . . . n 2. 00 inches AREA. . : 46.95 Acres TIME INTERVAL. . . . . 10.00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 165. 17 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0.00 Acres CN. . . . . 98. 00 TcReach - Sheet L: 300.00 ns:0. 4000 p2yr: 2.00 s:0- 0 30 TcReach - Shallow L: 500. 00 ks: 3.i-0 s: 0. 0t300 TcReach -- Shallow L: 1500- 00 f•s: 3. 00 s:i_r.0067 PEAK RATE: 1 .75 cfs VOL: 2. 36 Ac-ft TIME: 770 min BASIN I i : PIE NAME: 2YR 24191-"i SBUH METHODOLOGY TOTAL, AREA. . . . . . . : 24. 39 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . 2 USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2.00 inches AREA. . . 23. 34 Acres TIME INTERVAL 10. 00 min CM. . . . . 82. 09 TIME OF CONC. . . . . . 54. 36 min IMPERVIOUS AREA ABSTRACTION C'OEFF: 0. 20 AREA. . 1 .05 Acres CN. . . . . 98. 00 TcReach -.. Sheet 1._: 300. 00 ns:0. 1: 00 p2yr: 2. 00 s:0. 0133 TcReach -- Shallow L.: 410.00 ks: 1. 0 st O.0146 TcReach •-• Shallow L: 160.00 ks: 5. 00 s:_3. 025 0 TcReach - Shallow L: 150.00 ks:5.00 s:0. 0400 TcReach -- Shallow L: 490. 00 k:s:5. 00 s:V.075« PEAK RATE: 1 .67 cfs VOL: 1 .42 Ac-ft TIME: 490 min 10 YEAR 5 19/95 Ostergaard Robinson & Assoc. Inc. page 1 TROV I T SKY PARK EAST BASIN SUMMARY 2YR , 1OYR & 1O rYR -----______ BASIN SUMMARY BASIN ID: OB NAME: IOYR 2=1 1 SBUH METHODOLOGY TOTAL AREA. . .. . . . . . 0.81 Acres SA'SEFLOWS: 0.00 cf s RAINFALL. TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2. 92 inches AREA. . . 0. 75 Acres TIME INTERVAL. . . . . 10. 00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 7. 81 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . . 0. 06 Acres CN. . . . . 98. 00 TcReach - Sheet L: 200. 00 ns:i_a. 4000 p2yr: 2. 00 s:0. C;350 PEAK MATE: 0. 15 cfs VOL: 0. 09 Ac-ft TIME: 490 min BASIN ID: ?_'•1= NAME: IOYR :24HR SBUH METHODOLOGY GY TOTAL_ AREA. . . . . . . . 0. 07 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . . USER I PERVIOUS AREA PRECIPITATION- . : 2. 92 inches AREA. . . 0. 37 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81 .00 TIME OF COLIC. . . . . : 54. 20 min IMPERVIOUS AREA ABSTRACTION COEFF; 0. 20 AREA 0. 00 Acres CN. . . . . 98. 00 TcReach - Sheet L: 150.00 ns: 0. 4000 p2yr: 2. 00 s: 0. 0080 PEAK RATE: 0. 05 cfs VOL: 0. 04 Ac--ft TIME: 490 min BASIN ID: DE NAME: 10YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 24. 39 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . ~ .2. 92 inches AREA. . : 12. 92 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 86.00 TIME OF CONC. . . . . : 20. 87 87 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 11 . 41 Acres CN. . . . . 98.oc) TcReach - Sheet L: 100.00 ns:0. 1 t_0 p2yr: 2.00 s:0.0100 TcReach - Channel L: 18i_0.t:0 kc:42. 00 s:0. 0250 PEAK RATE: 10.66 cfs VOL: 4. 28 Ac--ft TIME: 480 min 5 19i95 D=tergaarb Robinson & Assoc . Inc.. page .._ TROV I TSKY PARK EAST BASIN SUMMARY ?YR q 1 i-i`' R & 100YR -_-.................................. -................. _•----____-- BASIN SUMMARY BASIN I D A OA NAME: 1 0YR 2 4HR SI UH METHODOLOGY TOTAL AREA. . . . . . . : 0. 59 Acres PA'SEFL DLL S: 0.00 cf RAINFALL TYPE. . . . . USER! PERVIOUS AREA A PRECIPITATION. . . . : 2. 92 inches AREA. . :,. 5 Acres TIME INTERVAL_. . . . . 10. 00 min CN. . . . = 81 . 00 TIME OF CDNC. . . . . . 17. 50 min IMPERVIOUS AREA ABSTRACTION COEFFe 0. 20 AREA. . : 0. 00 Acres CN. . . . < 98. 00 TcRt=.63cki ~• .:a(sf'et L: 100. _;? ns: 1. 4i:.it. p"_i're 2 _ 60i= PEAK RATE: 0. '1 4cf s VOL: 0.06 tib Ac-f t TIME: 4BO min BASIN I L`. t..}y i NAME: 10YR 2 ..It', SBUH METHODOLOGY TOTAL AREA . . 0. 81 81 Acres BASEFLOWSc t_i. 00 cf s RAINFALL TYPE. .. . . U S E R 1 PERVIOUS PRECIPITATION. .. . . . 2. 92 incites AREA. . : 0. 75 Acres f' . . . . . 81 . 00 TIME INTERVAL. . . . . 1 t1.. >i_i min].i�i i.•"N TIME OF COi' C. . . . . , 37. 81 min IMPERVIOUS AREA t-1r;S l�i�.AC L ION i_t_:EF1�= 0. 20::i_i AREA. . : 6 Acres CN. . . . : U. i.f:_i l'fi_ ei' 200. 00 s:0. 4000 p2yrN 2. 00 s: 0. 0350 PEAK RATEr 0. 15 cfs VOL: 0. 0 Ate.-f t TIL:Q 490 min BASIN ID: i tC NAME 1 t iYR 24HR SBUH METHODOLOGY TOTAL.. AREA. . . . . . . .. 3. 10 Acres BASEFLOWS: 0. 00 cts RAINFALL TYPE. . .. . 2 USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2. 92 inches AREA. . . 2. 98 Acres TIME INTERVAL. . . . . 10.00 min CN. . . . : 81 . 00 TIME OF CO NC 43. 93 min IMPERVIOUS AREA ABSTRACTION TION COE=FF: ti. 2ti AREA. . : 0. 12 Acres CN. . . . : 98. 00 TcReach ..... Sheet L: 3i_iti. 00 nsd i_i. 4ti0i_i :f2yr : 2. 00 s: 0. 076(-) TcReach - Shallow L..a 400. 00 L:s: 5. 00 se0. 057ti PEAK RATE: 0. 53 C:i•-s V!:}L._^ 0. 34 Fa c__.-r _ TIME: 490 i i t l I-t pl 5/19/95 Ostergaard Robinson & Assoc. Inc. page -. TROV I TSKY PARK EAST BASIN SUMMARY 2YR . 10YR & 100YR ._ BASIN SUMMARY BASIN ID: OD NAME: 10YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 6. 83 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE.. » . . . USER! PERVIOUS AREA PRECIPITATION. . » » ,. 2. 92 incites AREA. . . 6. 59 Acres TIME INTERVAL. . . . » 10.00 shin CN. . . . » 81 . 0o TIME OF CDNC. . . » » d 63. 16 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : �7. 24 Acres TcReach -- 'Sheet L: 300. 00 ns'. i-?. 40i?tr p2yr: 2. 00}0 _.,: '_?. 0400 TcReach -- Shallow Q 550. 00 k:s: . 00 s: ? G182 PEAK RATE: 0. 96 cfs VOL: 0. 74 Ac-tt TIME: 490 :,yin BASIN 11): DIE NAME: 10YR 24HR SBUH METHODOLOGY TOTAL AREA . 0. 69 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . . USER! PERVIOUS AREA PRECIPITATION. . . . . 2. 92 inches AREA. . : 0. 69 Acres TIME INTERVAL. . . . . 10. 00 min LN. . . . 81 . 0(-,) TIME OF CONE. . . . . : i 0.31 min IMPERVIOUS AREA ABSTRAC�I ION CO(__FF: i? (.-) AREA, 0. 00 Acres TcReach --' Sl-ii=et 4_. 300. 00 n s: i..?.: 40i.?i_? p2yr» 2. 00 s: 0. C?i6.:; PEAK 1{A i E: C). 09 cfs VOL: 0. 07 A t TIME: 500 min BASIN I D: OF NAIME: 1}:_?YR 24HR SBUH METHODOLOGY TOTAL- AREA. . . . . . . . 0. 37 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER I PERVIOUS Ai"-r'EA PRECIPITATION. . . . . 2. 92 inches AREA. . . 0. 37 Acres TIME INTERVAL. . . . . 10. 00 min CN„ . . . . 81 . 00 TIME OF CONC. . . . . : 54. 20 i min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 2C) AREA. . : 0. 00 Acres C:N. . . . » 98. 00 TcReach -- Sheet L: 150. 00 ns: O. 4000 p2yr: 2. 00 s: 0. 008ii PEAK RFi_I.E: 0. 05 cfs VOL: 0. 04 Ac-ft. TIME: 490 min 5/ 19/95 OstergaarU Robinson & Assoc. inc . page :k TROY I TSKY PARK EAST BASIN SUMMARY 2YR , 1 GYR & 1 0 0YR BASIN-SUMMARY ===-__________-= BASIN ID: OG NAME: 10YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 46. 85 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2. 92 inches AREA. . . 46. 85 Acres TIME INTERVAL 10. 00 min CN. . . . : 81 .00 TIME OF CONC. . . . . : 165. 17 min IMPERVIOUS AREA 4 ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres CN. . . . . 98. Cat3 TcReach -- Sheet L: 300.00 ns:0. 4000 p2ylr-: 2.00 s:0. 03.30 TcReach - Shallow L: 500.00 k:s: 3. Cis? s:0.0900 TcReach - Shallow L: 1500.00 ks:3. 00 s:0.0067 PEAK RATE: 3.83 cfs VOL: 4. 89 Ac-ft TIME: 650 mim BASIN I .i: PE NAME: 1 t.'_}'YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 24. 39 Acres BASEFLOWS: 0. 00 cfs RAINFALL_ TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 2. 92 inches AREA. . . 23. 34 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 82. 09 TIME OF CONC. . . . . : 54.36 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 1 . 05 Acres Cry. . . . . 99. 00 TcReach - Sheet L_: 300. 00 ns:0. 1300 p yr: 2. 00 s:0. 0133 TcReach - Shallow L: 410.00 k:s:5.00 s: 0. 0146 TcReach - Shallow L: 160. 00 k:s:5. Crib s:U. 025ii TcReach - Shallow L: 150.00 k:s:5.00 s:G. 0400 TcReach - Shallows L: 480. 00 k:s:5. 00 s:0. 0750 PEAK RATE: 4. 06 cfs VOL: 2.81 Ac-ft TIME: 490 rain k r 100 YEAR 5/19/95 Ostergaard Robinson & Assoc. Inc. gage 1 TROVITSKY PARK EAST BASIN SUMMARY 2YR . 1 i_}YR & 1 i OYR BASIN SUMMARY BASIN N I D w €=B NAME: I OOYR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0. 81 Acres BASEFLOWS: 0.00 cis RAINFALL. TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 3. 92 inches AREA. . . 0. 75 Acres TIME INTERVAL 10.00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 37. 81 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 06 Acres CN. . . . . 98.00 TcReach -- Sheet L: 200. 00 ns:€;a. 4000 pi'_yr: 2. 00 -:0. 0:_t5i_ PEAK RATE: 0. 27 cis VOL: 0. 15 Ac-f t TIME: 480 min BASIN 1 Li^ OF NAME.: 1Ot�Yf-`: 24HR SBUH METHODOLOGY Y• TOTAL AREA. . . . . . . . 0. 37 Acres BASEFLOWS: 0. 00 cis RAINFALL TYPE. . . . : USER! PERVIOUS AREA PRECIPITATION. . . . . 3. 92 inches AREA. . . 0. 37 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 54. 20 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. .. : 0. 00 Acres CN. . . . . 98. 00 ) TcReach -- Sheet L: 150. 00 n s:€:y. 4000 G2yr: 2.00 s: 0. 0080 PEAT:: RA"1 E: 0. 10 cis VOL: 0.06 6 Ac-i t TIME: 490 mi nt BASIN ID: DE NAME: 1 OOYR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . .. . 24. 39 Acres BASEFLOWS: 0. 00 cis RAINFALL 'TYPE. . . . u USER1 PERVIOUS AREA PRECIPITATION. . „ . . 3. 92 inches AREA. . . 12.98 Acres TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00 TIME OF CONC. . . . . : :: 0. 87 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 11 .41 Acres CN. . . . . 98.00 TcReach - Sheet L: 100.00 ns:0. 15L:0 p2yr: 2.00 s:€j. 01€_0 TcReach --• Channel L: 1800.Cu_r kc: 4 .0 r s:t_r.0250 PEAK RATE: 15. 60 cis VOL: 6. 18 Ac-•f t TIME: 480 min 1 5f19/95 Oster-gaard Robinson & Assoc. Inc. page TROYITSKY PARK EAST BASIN SUMMARY YR 10YR & 100YR t.;• BASIN SUMMARY BASIN ID: OA NAME: 100YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0. 59 Acres BASEFLOWS: 0. 00 c•fs RAINFALL TYPE. . . . : USER i PERVIOUS AREA PRECIPITATION. . . . . 3.92 inches AREA. . . 0.59 Acres TIME INTERVAL. . . . : 10.00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 17.50 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0.00 Acres CN. . . . . 98. 00 TcReach -- Sheet L: 100. 00 ns:0. 4000 g2yr: 2.00 s: 0. 0600 PEAK RATE: 0. 25 c s VOL: 0. 10 Ac-•ft TIME: 480 min - BASIN ID: OB NAME: 100YR 0YR 24HR SBUH METHODOLOGY TOTAL AREA „ i . 81 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 3. 92 inches AREA. . . 0..75 Acres I TIME INTERVAL. . . . : 10„00 min CN. . . . : 81 .00 TIME OF CONC. . . . . : 37.81 min IMPERVIOUS AREA ABSTRACTION rOE- -: 0.20 AREA. . : 0. 06 -c -c�__ CN. . . . . 99. 00 TcReach •-- Sheet Le 200. 00 ns„ li. 4000 p2yr. 2. 00 s: 0. (a_i5 a PEAK RA`iG::... Ca. .,_r CfC•: VOL: 0.. 15 f-tC--•r•t TIME: 480 min BASIN I D: OC NAME: 100YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 3. 10 Acres BASEFLOWS: 0. 00 c•fs RAINFALL TYPE. . . . : USER1 >'=ERVIOUS AREA PRECIPITATION. . . . : 3. 92 inches AREA. . ; 2. 98 Acres TIME INTERVAL. . . . . 10.00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 43. 93 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. ..2'.•0 AREA. . : t_a. 12 Acres CN. . . . . 98.00 TcReach •-- Sheet L: 300.00 ns:G.4000 p2yr: 2. 00 s:0.0760 TcReach -- Shallow L: 400. 00 k:s:5.00 s:0.0570 I' PEAK RATE: 0. 94 c•fs VOL: 0. 55 Ac--•ft TIME: 490 min 19/95 Ostergaard Robinson ?< Assoc. Inc. page TROV I TSKY PAW--. EAST BASIN SUMMARY � 2YI-i-_10't'R.-&_ lt-)t_)Y.r,=c.-:_-•-----•____---•-""---___________________________---_.-.....c� BASIN SUMMARY SBUH METHODOLOGY TOTAL rtL_ AnEA. . 6. 91 Acres ESASEs LOl=3S: 0. 00 c, RAINFALL TYPE. . . . . USER! PERVIOUS AREA PRECIPITATION. . . . . = . 92 inches. AREA. . . 6. 59 Acres TIME INTERVAL- . : 10. 00 min CN. . . . . 81 . 0o TIME OF CONC. . . . . . 63. 16 min IMPERVIOUS AREA ABSTRACTION COEF s 0. 20 AREA. . : 0. 24 Acres CN. . . . . 98. i-)i T cReach •-- Sheet L: 300. 00 n s:0. 4t,t00 2 y r. 2. 00 s: t . 040() -IcReach -... Shallow L..: 550. 00 E::s` 5.00 sy =). $)1g2 PEAK RATE: 1 . 73 {=is VOL: 1 . 20 Ac-ft TIME: 490 min BASIN 11 w OE NAME: 1 0._%Y R '_'ii.s-!(= SBUH METHODOLOGY H11I?C.TC.IJG'Y TOTAL AL AREA 0. 69 Acres UASErLOWSt 0. 00 cis s RAINFALL TYPE. . . . . USE_R 1 PERVIOUS 1-`tR).=A PRECIPITATION. . . . . _. . .__ inches AREA. . . 0. 69 Acres TIME INTERVAL. . . . . 10. 00 min CN. . . . e 81 . )(j TIME. OF C:;ONNC•. . . . . a 70. 31 min IMPERVIOUS AREA ABSTRACTION COEFFg 0 ) AREA. . : 0. 00 Acres _ . f_I_ PEAK RATE: 0. 16 cis CIL..; 0. 12 r§ -f t TIME: 't..) ;t"s i i BASIN ID; OF NAME: 1 0r j`•r R '._'jTHR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 0. 37 Acres BASEk=LOWS: 0. 00 C F RAINFALL TYPE. . ,. . . USER 1 PERVIOUS AREA PRECIPITATION. . . . . 3. 92 inches AREA. . : t_) Acres TIME INTERVAL. . . . . 10. 00 min CN. . . . . 81 . 00 TIME OF C::C:1NC. . . . . . 54. 20 min IMPERVIOUS PERVIOUS AREA ABSTRACTION COEF1= . 0. 2 u AREA. . : 0. 00 Acres C N. .. . . . 98. 0C) TcReach - Sheet I__: 150. 00 i t s: 0. 4t_00 p::yr : 2. 00 s: 0. C 08() PE=AI•::: RATE: 0. 10 c fs VOL..t 0., 06 Ac-...rt TIME: 490 min 5/19i 95 Osstergaar d Robinson & Assoc. inc. page 4 TROY I TSK;Y PARK:: EAST BASIN SUMMARY AD, BASIN SUMMARY BASIN I D: OG NAME: 1 0r_?YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . : 46. 95 Acres BASEFLOWS: 0. 00 cT_- RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . : 3. 92 inches AREA. . : 46. 85 Acres. TIME INTERVAL. .. . . . 10. 00 min CN. . . . . 81 . 00 TIME OF CONC. . . . . : 165. 17 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 0. 00 Acres CN. . . . . 98. 00 TcReach - Sheet L: 300. 00 ns:0. 4000 p2yr: 2. 00 s: 0. 0 ,30 TcReach - Shallow L: 500. 00 is: 3.c_?0 s:0.0800 TcReach -- Shallow L: 1500. 00 ks: :_*-,. try=? s: 0. 0067 PEAK:. RATE: 6. 74 cfs VOL: 8. 02 Ac-ft TIME: 530 min, BASIN I D: PE NAME:: 100YR 24HR SBUH METHODOLOGY TOTAL_ AREA. . . . . . . : 24. 39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . . 3. 92 inches AREA. . . 23. 34 Acres TIME INTERVAL. . . . & 10. 00 min CN. . . . . 82. 09 TIME OF CONC. . . . . w 54. 36 min IMPERVIOUS AREA ABSTRACTION COL--FF: 0. 20 AREA. . : 1 . 05 Acres CN. . . . . 98. 00 TcReach -.. Sheet_ L: 300.00 ns:0. 1:700 pi2 yr: 2. 00 s: 0. 01"3:-; TcReach -- Shallow L: 410.00 k:s:5. 0 ? s:0. c_?146 TcReach - Shallow L.: 160. 00 k:s:5. cacti s:0. t 250 TcReach - Shallow L: 150. 00 ks:5.00 s:0. C?400 TcReach - Shallow I._.: 480.00 ks:5. 00 s:0.0750 PEAK; RATE: 7. 10 cfs VOL: 4.49 Ac-ft TIME: 490 main EAST BASIN STORM ROUTING & BACKWATER ANALYSIS PRE-0EVELOPED CONDITIONS / 19:'95 vstergaard Robinson & Assoc. Inc. page 1 TRJV I TSI<Y PARK 2YR STORM ROUTING &BACKW nTER PRED'EVELui'ED 1.1i::i'((:JR`i' OF 1-I`i'Df;:OGF2AF=H JC,-:['v'I-f.Y-`_______________.___.__ Date of Session: 5119195 CU RHIS MOVE PE to 18 1.6670 cfs 1.4250 ac-ft S.17 hrs ROUTE HYDROGRAFH 18 THROUGH REACH N! Hvdrograph shifted 0.10 min Hvdrograph shifted 0.05 min Hydrograph shifted 0.07 min Network N1 Reach <AREA> (Act Q> (9 Full) 7, Full Ndepth (Diam> <NVel> <FVel> Carea 22 39 i v Reach) �2 OG -Y.J'I ..fJ tDf t�h .._d:iii ��.YL fi C1 71.24 2.91 4.27 68.24 L 27 1100 105 143 06 CA 71.03 2.93 (Ditch Reach) 0.57 1.38 0A 02 71.83 193 4.31 6102 1.26 12.00 191 149 OB 72.64 2.97 (Ditch Reach) 0.66 1.76 OB cc 75.74 3.12 (Ditch Reach) 0.43 4.18 UC OD 82.57 3.44 (Ditch Reach) 0.45 4.33 OD T .i 57 T T 2 � 'l T 29 C,, 8t.s; ..44 16.6o L0.?0 _.41 L4.00 .1f ... 5 OE 83.26 3.46 (Ditch Reach) 0.96 1.01 DE OF 83.63 3.47 (Ditch Reach) 0.91 1.05 OF HGLINE HG1 Hydraulic Gradeline for Reach 461 (-FROM-) (--TO--) <FLOW> floss Ent HGL EntLoss ExtLoss Out Let Inlet AppHead BndHead vunHead HeadWtr -cbimh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- Ditch OF Start El: 492.37 OF: Upstream N.S. 492.38 ft (BkWtr) Depth at 85.00 ft; V 38 ft. OE: Upstream W.S. 472.46 ft (BkWtr) Depth at 225.00 ft: 1.05 ft. E3 E 3.44 0.00 492.46 0.00 0.02 492.48 491.60 0.00 0.00 0.00 492.48 495.20 OD: Upstream W.S. 492.48 ft (BkWtr) Depth at 210.00 ft: 13.19 ft. CC: Upstream W.S. 495.32 ft (Gravity) Gravity flow at upend, @(200.00 ft) Trans dist: 181.98 ft OB: Upstream W.S. 495.86 ft (Gravity) Gravity flow at upend, @( 4100 ft) Trans disc: ft C2 OB 2.93 0.11 495.35 0.04 0.22 495.61 495.98 0.00 0.00 0.00 495.98 497.20 CA: Upstream W.S. 496.57 ft (Gravity) Gravity flow at upend, @(180.00 ft) Trans dist: 163.61 ft C1 A 2.91 0.20 tw & do (dc: Inlet Ctrl Assumed 497.16 0.00 0.00 0.00 497.16 498.00 06: Upstream W.S. 528.85 ft (Gravity) Gravity flow at upend, @(380.00 ft) Trans dirt: 6.93 ft 5/19/9 5 Ostorgaard Robinsor-, & Asscc. Ir-,c. pagE 1 T R 0 V I TSF:::Y F'ARk:: 10Y-rR STO RM ROUT I(�G BALci::'w",TC R F REL?EVEL_OF'ED H:1 STORY OF' HYDROGRAF'H ACT I V I TY Date of Session: 5/19/95 CL EARHIS MOVE PE to 19 4.0596 cf5 2.8069 ac-ft 8.17 hrs ROUTE H'(DROGRAPH 19 THROUGH REACH H1 Hydrograph shifted 0.13 min Hydrograph shifted 0.07 min recommended time interval: 0.22534 min Waterkrks will iu5t shift the hydrograph nydrograph shifted 0.30 min Hydrograph shifted 0.05 min RetwV, F:each (AREA: 'Act Li> (i Full; 7 Full ydepth +;Diam,, Mel) ;Ft�el> Carea ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- OG 24.39 4.01 (Ditch Reach) 0.58 5.89 C1 11.24 7.31 --------Pressure Flow-------- 9.31 DG CA 71.83 7.38 (Ditch Reach) 0.96 1.75 CA C2 11.K 7.38 --------Pressure Flow-------- 9.40 r 7 10 J 1 n 1 n. - 0I 72.64 1.J (Ditch Reach) 0.94L.GL U DC i5.i4 '.88 iDit[!i Reach) 0.61 5.21 OC OD 82.51 8.70 (Ditch Reach) 0.64 5.46 OD �, �5 n 82. �.i0 o.6J JL..JF �. J .t11 J.i OE 83.26 8.74 (Ditch Reach) 1.22 1.27 OE OF 83.63 8.75 (Ditch Reach) 1.29 1.J2 OF .461iidc H61 Hydraulic Gradeline for Reach HG1 (-FROM-> (--TO--) (FLOW> floss Ent HGL EntLoss ExtLoss Outlet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim--- --------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------- Ditch OF Start El: 493.17 OF: Upstream W.S. 493.18 ft (BkWtr) Depth at 85.00 ft: 2.18 ft. OE: Upstream W.S. 493).21 ft (BkWtr) Depth at 225.00 ft: 1.80 ft. E3 E 6.70 0.02 493.22 0.02 0.12 493.J7 491.82 0.00 0.00 0.00 493.37 495.20 OD: Upstream W.S. 493.37 ft (BkWtr) Depth at 210.00 ft: 14.08 ft. CC: Upstream W.S. 495.50 ft (Gravity) Gravity flow at upend, @Q00.00 ft) Trans dist: 192.13 ft OB: Upstream W.S. 496.14 ft (Gravity) Gravity flow at upend, e( 40.00 ft) Trans di5t: ft C2 DB 1.38 0.70 496.84 0.27 1.37 498.49 499.68 0.00 0.00 0.00 498.68 497.20 CA: Upstream W.S. 498.69 ft (BkWtr) Depth at 180.00 ft: 2.69 ft. C1 A 7.31 1.29 499.98 0.21 1.J5 50i.59 499.96 0.00 0.00 0.00 501.59 498.00 06: !upstream W.S. 529.01 ft (Gravity) Gravity flow at upend, @(380.00 ft) Trans dirt: 61.09 ft � co..�oa.c.i�y is eXeee0�2�, t L f'. T JI .I�.'`i:J� Jr-.LCf-C�ctr_tf C� �.1�J1r�Sl_)r: ¢' i=1SSlJL. i{-il_.. !7c:'1Qe 'T F�0V I'T.V-,*Y F'ARK :B^tCF::WATER F'FiEDEVEL-OF'ED ��T.:7-( L)F'.�T� OFFi YL�1-�t`GF-.AFC A ALJ 1 i v 1 1 'i Date of Session: 5/19/95 CLEARHIS MOVE PE to 20 7.1047 ifs 4.4888 ac-ft S.17 hr5 ROUTE HYDROGRAPH 20 THROUGH REACH NI Hydrograph shifted 0.07 min Hydrograph shifted 0.04 min recommended time interval: 0.19410 rein Waterworks will just shift the hydrograph Hydrocraph shifted 0.26 Mir, Hydrograph shifted 0.05 air, Network ii1 reach "REA> "Act Q� Ful" Full "depth i;Diam; (We, Cr- area OG 24.39 7.07 (Ditch Reach) 0.72 6.78 C1 7f.24 13.28 --------Pressure Flow-------- 16.91 OG DA 71.83 13.41 (Ditch Reach) 1.12 2.04 OA Co 71.83 13.41 Pressure Flow-------- 17.07 DE 72.64 13.62 (Ditih Reach) 1.17 2.57 OB OC 75.74 14.33 (Ditch Reach) 0.76 6.12 OC OD 82.57 15.85 (Ditch Reach) 0.80 6.34 OD 82.57 15.85 16.63 95.35 18.i4 24.00 6.02 5.29 BE 83.26 15.87 (Ditch Reach) 1,52 11.48 BE OF 83.63 15.91 (Ditch Reach) 1.61 1.53 OF HGL inE HGI Hydraulic Gradeline for Reach HGI <-FROM-> :--TO--> tFLOW> floss Ent HGL EntLoss Er:tLos5 Outlet Inlet AppHead Br,dHead 1unHead HeadWtr -cb/mh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- Ditch OF Start El: 493.77 OF: Upstream B.S. 493.78 ft (BkWtr) Depth at 85.00 ft: 2.78 ft. BE: Upstream W.S. 493.80 ft (BkWtr) Depth at 225.00 ft: 2.40 ft. C3 E i5.85 0.07 493.87 0.06 0.40 494.35 492.36 0.00 0.00 0.00 494.35 495.20 DO: Upstream W.S. 494.35 ft (BkWtr) Depth at 210.00 ft: 15.06 ft. OC: Upstream W.S. 495.81 ft (BkWtr) Depth at 200.00 ft: 0.92 ft. OB: Upstream W.S. 496.37 ft (Gravity) Gravity flow at upend, @( 40.00 ft) Trans dirt: ft LC OB 13.41 2.32 498.69 0.90 4.52 504.12 505.12 0.00 0.00 0.00 505.12 497.20 GA: Upstream W.S. 505.12 ft (BkWtr) Depth at 180.00 ft: 9.13 ft. C1 A I3.2"8 4.26 509.JS 0.89 4.44 514.71 506.18 0.00 0.00 0.00 514.71 498.00 OG: Upstream W.S. 529.15 ft (Gravity) Gravity flow at upend, @0180.00 ft) Trans dirt: 231.91 ft COL/oo�� / is 9_XCer_c EAST BASIN STORM ROUTING & BACKWATER ANALYSIS � DEVELOPED CONDITIONS 5111"71/9`� D�-+ergaar-d Rob inson-t _. Assoc, issc. page 1 .ate of Session: 5/19/95 CLEARHI5 ROUTE HYDROGRAFH 4 THROUGH REACH N1 Hydropraph shifted 0.11 min Hydrov aph shifted 0.06 min Hydrograph shifted 0.07 min Network N1 Reach CAREA> :Act ?? .F? Full; 7 Full Ndepth Oiam) !N'M :F`del. Carea "uG 24.39 0.15 Mitch Reach) 0.31 3.81 Ci 71.24 2.31 4.27 54.21 6.30 12.00 5.54 5.43 OG CA 7i.83 2.33 (Ditch Reach) 0.52 1.30 CA 'T T 31 5d 2 2 C C yl C2 ;1.8J _.33 4.J1 J�.06 6.:.9 1�.00 J.6c J. :, ,�.6. "4 tn, Reach, 0.61 1.66 ri. iC 4 1 (D ut;r it 9 1: i#ch Reach) U.9 J9 J.9J iJL OD 82.57 ...75 (Ditch Reach) 0.41 4.0 OD C3 82.57 2.75 16.63 16.56 6.61 24.00 3'.92 5.29 GE 83.26 2.78 (Ditch Reach) 0.79 0.95 OE OF 83.63 2.79 (Ditch Reach) 0.84 0.99 OF HGLI)dE HGi Hydraulic Gradeline for Reach HG1 :-FROH-) -10--> :FLOW? floss Ent HGL EntLoss ExtLoss Ou#Let Inlet AppHead BndHead dunHead HeadWtr -chia�t�- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- ---loss- --loss- --Elev- --Rim-- Ditch OF Start El: 492.37 OF: Upstream W.S. 492.38 it (BkWtr) Depth at 85.00 f#: 1.38 ft. OE: Upstream W.S. 492.43 ft (BkWtr) Depth at 225.00 ft: 1.03 ft. C3 E 2.75 0.00 492.43 0.00 0.01 492.44 491.57 0.00 0.00 0.00 492.44 495.20 OD: Upstream W.S. 492.44 ft (BkWtr) Depth at 210.00 ft: 13.15 ft. OC: Upstream W.S. 495.28 ft '(Gravity) Gravity flow at upend, @(200.00 ft) Trans list: IBI.92 ft OB: Upstream W.S. 495.81 ft (Gravity) Gravity flow at upend, @( 40.00 ft) Trans dirt: ft C2 OB 2.33 0,01 495.35 0.03 0.14 495.51 495.53 0.00 0.00 0.00 495.53 497.20 GA: Upstream W.S. 496.51 ft (Gravity) Gravity flow at upend, @(180.00 ft) Trans di5t: ft Cl A 2.31 0.13 tw It do Cdc: Inlet Ctrl Assurred 496.76 0.00 0.00 0,('10 496.76 498.00 06: Upstream W.S. 528.74 ft (Gravity) Gravity flow at upend, @(380.00 it) Trans dirt: 3.45 ft - i'r':"i:; (Is :�i--r L3.-ai`A Fk(ot1.-ii.li rl `+. As_-St3C. l;i:_. �scliJi� t PARIKI- :1 ?YR a-i 01r" 1 FROUT11\16 ry&FAC:f::? )rE Fi I)EVEt-OPED } i'tI)F;CJt�F AF'H ACl'JVT i Date of Se55ioR: 5/19/95 CLEARHIS ROUTE HYDROGRAPH 5 THROUGH REACH N1 Hydrograph shifted 0.20 min Hydrograph shifted 0.10 min recommended time interval: 0.24992 min WaterWorks will just shift the hydrograph Hydrograph shifted 0.33 min Hydrograph shifted 0.06 min Network N1 Reach .r A iAct a: eQ Fulcr % Full Ndepttl CDiam; (idle,. crael: Carea OG 24.39 I.45 (Ditch leach: 0.4U 4.57 Ci Pressure rr 1i.24 4.b� -------- ac , ,_..Siin.. Fiow-------- :5.18 uu ON 71.83 4.89 :Ditch Reach) U.72 1.58 LA C2 71.83 4.89 --------Pressure Flow-------- 6.23 OB 72.64 4.96 (Ditch Reach) 0.80 2.U0 OB LC 75.74 5.18 (Ditch Reach) 0.52 4.14 LC OD 82.57 5.73 (Ditch Reach) 0.54 4.91 OD C's 82.57 5.73 16.63 34.44 9.71 24.00 4.80 5.29 BE 83.26 5.78 (Ditch Reach) 1.04 1.I5 BE OF 83.63 5.80 (Ditch Reach) 1.10 1.I9 OF HGLINE HGI Hydraulic Gradeline for Reach HG1 FROM-: --TO-- :FLruW) floss Ent HGL EntL055 E::tLoss Outlet Inlet AppHead Bndhead JunHead HeadWtr -chi i- ------ -------- cos -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --lo5s- --Elev- --Rig,-- Ditch OF Start E1: 493.17 OF: Upstream W.S. 493.17 ft (BkWtr) Depth at 85.00 ft: 2.17 ft. BE: Upstream W.S. 493.19 ft (BkWtr) Depth at 225.00 ft: 1.78 ft. C3 E 5.73 0.01 493.19 0.01 0.05 493.26 491.69 0.00 0.00 0.00 493.26 495.2U ON Upstream W.S. 493.26 ft (BkWtr) Depth at 210.00 ft: I's.97 ft. OC: Upstream W.S. 495.41 ft (Gravity) Gravity flow at upend, @(200.00 ft) Trans dirt: 191.76 ft OB: Upstream W.S. 496.00 ft (Gravity) Gravity flow at upend, @( 40.00 ft) Trans disc: ft C2 OB 4.89 0.31 496.31 0.12 0.60 497.04 497.11 0.00 0.00 0.00 497.i1 497.20 OA: Upstream W.S. 497.15 ft (BkWtr) Depth at 180.00 ft: 1.16 ft. C1 A 4.85 0.57 497.72 0.12 0.59 498.43 498.32 0.00 0.00 0.00 498.43 498.00 OG: Upstream W.S. 528.82 ft (Gravity) Gravity flow at upend, @(380.00 ft) Trans dirt: 22.10 ft �s eK ce eded s� 9t-5 Dst r aar d Robinson -. A soc. Inc.. EtC4 1 •1-ROV:1-T'ci(::Y F';yRI" Y.BAC:l::.WA-)-En: DEVELOf'ED -FORY OF HYD�:OuR:t=,F�H aO�FiVI TY h$I{� Date of Session: 5/19/95 CLEARHiS ROUTE HYDROGRAPH 6 THROUSH REACH N1 Hydrou aph shifter 0.11 min Hydrwraph shifted 0.06 Pin recommended time interval: 0.21467 Pin WaterWorks will just shift the hydrograph Hydrograph shifted 0.29 ruin Hydrograph shifted 0.05 min Network Ni Reach <:AREA, iyct Di :? Fuli:` 1 Full Ndepth {Dias„ :NVel,` tFVei; Carea ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- 'f„ - T�7 (Di 1 l tfi Reach} � C4 C iC OG 24..7 �. t J. � Ci 71.24 8.95 --------Pressure Flow- 11 '9 OS OA 71.c"3 9.01 (Ditch Reach) 0.94 1.84 OA C2 71.83 9.01 --------Pressure Flow-------- 11.47 O 9.10 Ditch each} 1.01 2.33 OB OC 75.74 9.46 (Ditch Reach) 0.65 5.51 OC OD 82.57 10.32 (Ditch Reach) 0.68 5.69 OD • L , T , r z c c7 c n- C 82.5. 10..ti2 16.63 62.05 17.68 24.00 ..a. s.29 OE 83.26 10.40 (Ditch Reach) i.30 1.3. OE OF 83.63 10.44 (Ditch Reach) 1.38 1.38 OF HGLiNE HG1 Hydraulic Gradeline for Reach HG1 FROM-> C--TO-- \'FLOW; floss Ent HGL EntLoss ExtLoss OutLet inlet AppHead BndHead dunHead HeadWtr -cb ij- -------- -------- cis -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- --------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------- Ditch OF Start E1: 493.77 OF: Upstream N.S. 493.77 it (84Wtr) Depth at 85.00 it: 2.77 ft. OE: Upstream W.S. 493.78 ft fBkWtr) Depth at 225.00 ft: 2.38 ft. L3 E 10.32 0.03 493.82 0.03 0.17 494.02 491.88 0.00 0.00 0.00 494.02 495.20 DO: Upstream W.S. 494.02 ft (BkWtr) Depth at 210.00 ft: 14.73 ft. OC: Upstream W.S. 495.57 ft (BkWtr) Depth at 200.00 ft: 0.68 ft. OB: Upstream W.S. 496.21 ft (Gravity) Gravity flow at upend, 0( 40.00 ft) Trans dirt: ft C2 OB 9.01 1.05 497.26 0.41 2.04 499.71 500.05 0.00 0.00 0.00 500.05 497.20�If OA: Upstream W.S. 500.05 ft (BkWtr) Depth at 180.00 ft: 4.06 ft. Cl A 8.95 1.93 501.99 0.40 2.01 504.41 501.23 0.00 0.00 0.00 504.41 498.00;E OG: Upstream W.S. 528.95 ft (Gravity) Gravity flow at upend, @0180.00 ft) Trans dist: 98.64 ft '� Coypa.cr �y is eXceeo�• ,4i2Y2? i WEST BASIN ,t� TROVITSKY PARK DOWNSTREAM ANALYSIS WEST BASIN Existing Condition: Storm water runoff from the site sheet flows along the northeast property line at a mean ground slope of 3-5% with a second growth forested native vegetative ground cover. Runoff sheet flows approximately 350 feet where it is intercepted in a newly constructed grasslined swale adjacent the ball field area. Post-developed runoff will either be dispersed at the property line or conveyed to the existing ditch via a new ditch or pipe if an easement can be acquired through the park property. This conveys runoff to the existing silt pond north of the ball field. The existing grasslined swale consists of a 3.1' flat bottom with gentle side slopes (see: Typical Existing Ditch Section West Downstream) and a natural drainage course slope of approximately 6.23%. Discharge from the silt pond is dispersed in the form of sheet flow with limited areas of flow concentration between the pond and wetland No. 16 approximately 160' downstream. The ballfield was under construction at time of inspection. Some sediment buildup was observed behind the check dams in the ditch. However, no sedimentation or erosion was observed below the silt pond. Conclusions and Recommendations: Standard detention in conformance with the 1990 Surface Water Design Manual was assumed for analysis of the west basin downstream system. No impacts from flooding or erosion are anticipated consequently no additional mitigation is proposed. WEST BASIN AREA BREAKDOWN & OVERLAND FLOW DISTANCES BASIN AREA OVERLAND FLOW DISTANCE AND SLOPE (rc REACH OW 17.41 AC 300' @ 0.5% 250' @ 1.0% PW 12.26 AC 230' @ 0.87% 340' @1.18% 170' @ 3.52% 210' @ 0.95% 350' @ 2.86% DW 12.26 AC 19.96 MIN. Note: OW = Offsite Basin West (Typical) PW = Pre-developed Onsite Basin West (Typical) DW = Developed Onsite Basin West (Typical) x 7\ Aj IN � J 1 1 5u hellse I roe e • B '() � `. �. .. .. erg M. 5It iTH �' �� , ram,.✓ \ �� / .I d E�R Jt 9. PL l �' \Al�'• .w iam b", low 50/ �sxvjj Cl- \� p R K,. Oec �i Li I ice.. .•.. ....s . �' j .... i <__, , ....r........�� _n � j ,�'• — �� _ •If� 1 Ts KENT SCH O PIER T C,])` ��-�� ,.ice• �,�:• ;;, '' ttellte .4 Q c� , � �..� S ST _ 7iM'IbA� ry.�,,,i:■,g: C'` „ ..• �t131 -=.. G •bd'6-' �� ... L-=`.�� .` J1 '`Cr� �► l sus c� .� p sCFlo OL 43 .AC el T. i1 ;rl�� j •� •'iiel�„•� ' i i q , 2 YEAR :X�TN • i ';i 5/19/95 Ostergaaru Robinson & Assoc. Inc. page 1 TROYITSKY PARK WEST BASIN SUMMARY 2YR , 10YR & 1 00YR t BASIN SUMMARY BASIN ID: DW NAME: 2YR 24HR SBUH METHODOLOGY .TOTAL AREA. . . . . . . : 12. 26 Acres BASEFLOWS: 0. 00 cis RAINFALL TYPE. . . . 2 USER1 PERVIOUS AREA PRECIPITATION. . . . > 2.00 inches AREA. . . 6. 38 Acres TIME INTERVAL. . . . . 10. 00 min CN. . . . . 86. 00 TIME OF CONC. . . . . : 19. 96 min IMPERVIOUS AREA ABSTRACTION COEFF : 0. 20 AREA. . : 5. 88 Acres CN. . . . . 98. 00 PEAL:. RATE: 3. 25 cis VOL: 1 . 32 Ac-x t TIME: 480 m i n BASIN I D: Oda NAME: ._`YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 17. 41. Acres BASEFLOWS: 0. 00 cis RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2.00 inches AREA. . : 17.41 Acres TIME INTERVAL_. . . . : 10. 00 min CN. . . . : 86.00 TIME OF CONC. . . . . : 55. 75 min IMPERVIOUS AREA S ABSTRACTION COEFF: 0, 20 AREA. . . 0. 00 Acres CN. . . . : 98. 00 TcReach - Sheet L: 300. 00 ns:0. 1500 p2yr: 2. 00 s:0. 005(:) TcReach - Shallow L: 250. 00 ks: 1 1 .00 s: 0. t 100 PEAK RATE: 1 . 65 cis VOL: 1 .23 Ac-ft TIME: 490 min BASIN ID: PW NAME: 2YR 24HR SBUH METHODOLOGY TOTAL AREA. . . . . . . . 12. 26 Acres BASEFLOWS: 0. 00 cis RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2. 00 inches AREA. . : 12. 26 Acres .TIME INTERVAL. . . . : 10.00 min CN. . . . : 81 . 28 TIME OF CONC. . . . . A 57. 56 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres CN. . . . . 98.00 TcReach - Sheet L: 230. 00 ns:0. 1 300 pSyr: 2. 00 s: 0.008*7 TcReach - Shallow L_.: 340. 00 k:s: 5. 00 s:0.01 18 TcReach -- Shallow L-.: 170. 00 ks:5. c_0 s:0. 035'. TcReach -- Shallow L: 210. 00 0 L s: 5.00 s: 0. 0095 TcReach - Shallow L-: 350. 00 ►<:w: . 00 s:0. 0 86 PEAL'; RATE: 0. 64 cis VOL..: 0. 63 Ac--ft TIME: 520 min 'i I I 10 YEAR I19195 Os'tergaarU Robinson & Assoc. Inc_. page 1 TROYITSKY PARE WEST BASIN SUMMARY 2YR K 1 0YR & 1 t=l0YR BASIN SLJMh1AFiY BASIN ID: BW NAME: 10YR 24Hf--: SBUH METHODOLOGY TOTAL AREA. . . . . . . : 12. 26 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . » 2. 92 inches AREA. . . 6. 38 Acres TIME INTERVAL_. . . . : 10.00 min CN. . . . : 86. 00 TIME OF CONC. . . . . : 19. 96 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 5. 88 Acres CN. . . . . 98. 00 PEAK RATE: 5. 47 cfs VOL_: 2. 16 Ac--ft TIME: 480 min BASIN ID: OW NAME: 10YR 24H SBUH METHODOLOGY .TOTAL AREA. . . . . . . . 17. 41 Acres BASEFLOWS: 0. 00 c.,cs RAINFALL. TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . : 2. 92 inches AREA. . . 17.41 Acre__ TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86.Oo TIME OF CONC. . . . . t 55. 75 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA- : 8. 00 s . .CN 0. Acres 00 TcReach -.. Sheet. L: 300. 00 ah! ns:O. 1500 p2yr: 2. 00 s: 0. x!05(i TcReach - Shallow L.. .;_.....+: E::s: a. 1 » - - - 1 00 PEAK RATE: 3. 58 cfs VOL: 2. 31. Ac-ft TIME: 490 min BASIN ID: PW NAME: 10YR 24HF,: SBUH METHODOLOGY TOTAL AREA. . . . . . . . 12. 26 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . . 2. 92 inches AREA. . . 12. 26 Acres TIME INTERVAL. .. . . 2 10. 00 min CN. . . . : 81 .28 TIME OF CONC. . . . . : 57. 56 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres CN. . . . . 98. 00 TcReach -- Sheet L: ?':.0.00 ns: 0. 1300 p2 yr: 2. 00 s:0. 0087 TcReach •- Shallow L: 340. 00 ks:O. 00 s: 0. 01 18 TcReach -- Shallow L: 170. 00 ks:5.00 s:rl.i_352 TcReach -- Shallow L: 210. 00 ks: 5.00 s: 0.0095 PEAK RATE: 1 . 74 cls VOL: 1 . 30 Ac--ft TIME:.: 490 min i l 100 YEAR 5/19/95 Ostergaard Robinson & Assoc. Inc. page 1 TROY I TSKY PARK WEST BASIN SUMMARY 2YR , 10YR & 100YR BASIN SUMMARY BASIN ID: DW NAME: 100Yf 24HE SBUH METHODOLOGY TOTAL AREA. . . . . . . . 12.26 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . = . 92 inches AREA. . . 6. 38 Acre TIME INTERVAL. . . . : 10.00 rain CN. . . . : 86. 00 TIME OF CONC. . . . . : 19. 96 min IMPERVIOUS AREA ABSTRACTION) COEFF: 0. 20 0 AREA. . : 5.88 Acres CN. . . . . 98.00 PEAK RATE: 7. 99 cfs VOL: 3. 12 Ac--+t TIME: 480 min BASIN I D: OW NAME: 1 00', R24HR SBUH !"!ETHODOLOGY TOTAL AREA. . . . . . . . 17. 41 Acres BASEFLOWS: 0. 00 cfs RAINFALL TYPE. . . . : USER 1 PERVIOUS AREA PRECIPITATION. . . . . 3. 92 inches AREA. . : 17.41 Acres TIME INTERVAL. . . . 10.00 min CNtd. . . . . 86.00 TIME OF CONC. . . . . : 55. 75 min IMPERVIOUS AREA ABSTRACTION COEFF: 0. 20 AREA. . . 0.00 Acres _ - . o = CN. . 98. 00 TcReach Sheet !_: "L,iaii. [`_a!i c-is;fa. li:aia p �'vr: `�'.0c:a ;;; 0, 0050 TcReach -- Shallow L_: 250.00 E::s: l l . z=0 s: 0. t 100 PEAK RATE: 5. 92 cis VOL: 3. 59 Ac-ft •TIME: 490 min BASIN! ID: PW NAME: 100YR 24HR SBUH METHODOLOGY TOTAL_ AREA. . . . . . . . 12. 26 Acres BASEFLOWS: 0. 00 c+s RAINFALL TYPE. , . . : USER1 PERVIOUS AREA PRE:CIPITATION. . . . . .. . 92 inches. AREA. . . 12. 26 Acres TIME INTERVAL. . . .. „ 10.00 min CN. . . . . 81 . 28 TIME OF CONC. . . . . : 57. 56 min IMPERVIOUS AREA ABSTRACTION COE-:FF: 0. 20 AREA. . : 0.00 Acres CN 98. 00 TcReach -- Sheet L: 230.00 ns:0. 1 c_a0 p2yr: 2.00 s:0. 0087 TcReach --• Shallow L: 340. 00 ksv 5.00 s:Ca.Ca1 18 TcReach - Shallow L: 170. 00 ks„ 5. 00 s: O. 0352 TcReach --• Shallow L: 210. 00 ks:5. 00 a: Ca. 009`; TcReach . ._t .,_ Shallow L_: 350..00 k s: `i. t-0 s: !i. 0`.. 8('S PEAK RATE: 3. 19 cfs VOL : � „ 12 Ac -ft TIME: 490 min WEST BASIN STORM ROUTING & BACKWATER ANALYSIS PRE-DEVELOPED CONDITIONS 5/" 1.8/ F4 iAssoc. inc:. pail E'. 1 ,_YR wl-tiRM ROUTING H 3-1-OF`r tlF ! i`r'UI;Olaf=I 'I-i i�LT I�'I l-`;' Date of Session: 5118,195 CLEARHIS MOVE PN to 10 0.6444 cfs 0.6301 ac-ft 8.67 Us ROUTE HYDROGRAPH 10 THROUGH REACH N2 Network N2 Reach <AREA> <Act G> « Full> R Full NdeRth <Diam> MeI> <FVeI> Carea N 29.67 2.26 (Ditch Reach) 0.18 2.87 ON HGLINE HG2 Hydraulic Gradeline for Reach HG2 <-FROM-> floss Ert HBL EntLoss ExtLoss Outlet Inlet AouHeatl SnrHeatl d.;;Head HeadNtr -ctr'rh- -------- -------- cr5 -loss- -Elev-- --loss- --loss- --Elev- --Elev- --fuss- --loss- --loss- --Elev- --Rig,-- Ditch N 'Start El: 516.78 Nc Upstream N.S. 551.45 ft {Gravity) Gravity flow at upend, 8(550.00 ft) Trans dist: ft n ROUTE HYDROGRAPH 10 THROUGH REACH S. L.1929 cfs 1.96" ac-it 9.0 hrs 513.13 ft 2042.26 cf IE3/9 15 i_�stergRLekr-d l i:ibini.;ol & HSSOC. Inc. page :L I-F;,ov I Tc:ik::Y PARK_ 1 C_)YR '.24 -IR S_I_l)RM ROUT"I hIG :2, _AC1:::bJATER PREDEVELOPED ----------------- F4I'STOR`f Of I i'r DF;i ICRA�'i. Ai T I G'I i `r Date of Session: 5/18/95 CLEARHIS CHANGE "1OYR 24HR° 2.92 PRECIP OB OF DE DW OA OB BE OD BE OF 06 OW PE PW MEND MOVE PW to 11 1.7382 cfs 1.2975 ac-7t 8.17 hrs ROUTE HYDROGRAPH 11 THROUGH REACH N2 Network N2 Reach (AREA; (Act O? <Q Full; 'i. Full Ndepth (Dian0 (id''el) <FJeI ?area W 29.67 5.23 (Ditch Reach) 0.28 3.67 OW H G L I N E HG2 Hydraulic Gradeline for Reach H62 (-FROM-: (--TO--) (FLOW) floss Ent HEL EntLoss ExtLoss Outlet Inlet AppRead BndHead JunHead HeadWtr -ch/mh- -------- -------- cfs -lass- -Eiev-- --los5- --loss- --Elev- --Elev- --1055- --Ions- --lass- --Elev- --Ria-- ---------------------------- ------------------------------------- { - Ditch W Start El: 516.88 x: Upstream W.S. 551.15 ,t ;Grav:tyi Gravity flow at upend, iu5u.100 ft) Trans di5t: ft ps.= ��rr rrr i r t REACH n RCu:c HYDROGRAPH 11 THROUGH REACH ,v 5.0152, cfs 3.6103 ac-ft 8.83 hrs 513.30 ft 3847.79 cf 5J 18i9 i f sstei-qaatd Robinson & Assoc. Inc. papa 1. TROV I TSP"'Y F'Aftk:: i 00YR :-31-Of-,.!`1 F�OUI-I NG p..i ACk::iilA-rEF': F'F:EDEVELOF'ED H I '3 iFORY OF f-IYl]f OGRAF'ff ACT I'v.. Date of Session: 5118195 CLEARHIS MOVE PW to 12 J.1B89 cfs 2.1217 ac-ft 8.17 Ctrs ROUTE HY)ROGRA,PH 12 THROUGH REACH N2 Network N2 Reach <AREA) CAct L> (Q Full> X Full Ndepth M aa> M el> <;FVeI> Carea ---------------------------------------------------------------------------- N 29.67 8.94 (Ditch Reach} 0.37 4.27 ON HGLINE HG2 Hydraulic Gradeline for Reach HG2 FRO}f-> ;--TO- :FLONf floss Ent_HGL EntLoss ErtLoss OutLet lnlet 4.04ead BndHead JurfHead HeadNtr -c'alash- -------- -------- cfs -loss- -Elev-- --lass- --lass- --Elev- --Ele:°- --loss- --loss- --loss- --Elev- --Rim-- Ditch N Start El: 516.97 N: Upstreaa N.S. 551.24 ft (Gravity) Gravity flow at upend, d(550.00 ft) Trans dirt: ft ROUTE HYnROGRA.PH 12 THROUGH REACH S cts 5.71U9 ac-ft 9.67 hrs 513.48 ft 5678.8, cf 8.7720 r wo WEST BASIN STORM ROUTING & BACKWATER ANALYSIS � DEVELOPED CONDITIONS /18/95 Oster-gaard Robinson & Assoc. Inc. page '. TROVITSKY PARK 2YR STORM ROUTING 4;BAC1`:ES AVER DEVELOPED HISTORY OF HYDROi.RAPH ACTIVITY Date of Session: 5/1E55 CLEARHIS ROUTE HYDROCRAPH 10 THROUGH REACH N2 Network N2 Reach :AREA; ;Act Q> (O Full> % Full Ndepth tDiam/' {NVel> CFVel> Carea Y 27.67 1.95 :Ditch Reach) 0.17 2.74 OW HULiNE Hut Hydraulic uradeline for Reach Hut FROM-> <--TO--> (FLOW> floss Ent HUL EntLoss ExtLoss Out Let inlet ,AppHead cndHead dunHead HeadWtr -cblih- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elea- --loss- --loss- --loss- --Elev- --Ris-- Ditch k Start El: 516.77 11: Upstream N.S. 551.03 ft Uravity7 Gravity flow at upend, 1150.00 ft) Trans dirt: ft ROUTE HYDROURAFH 10 THROUGH REACH S 1.4171 cfs 2.5305 ac-ft 9.00 hrs 513.11 ft 1849.74 if 0 i�:= liS�F�l�i =tc�i-C� :c=ib ns r-i =c H-SSuC. .ti-iC. jtcti;f? PAC1:J-JP T E=R POMMEVEL_OPED I-1:{31'01-I:Y OF- I-t1'Dl=iOCt RPIPH AC.T I V I Y`r Late of Session: 5/18/95 CLEARHiS ROUTE HYDROGRAPH 11 THROUGH REACH N2 Network N2 Reach tAREA? <Act Full), % Full Ndepth <Diam; tNVel; "FVel> Carea N 29.67 3.68 (Ditch Reach) 0.24 3.32 LTN HGLINIE HG2 Hvdraulic Gradeline for Reach H62 ,-FROM-i .--TD--i :FLOW? floss Ent HGL Ent Loss ExtLoss Outlet inlet AppHead BndHead JunHead HeadNtr -ch/eh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rit-- qii Ditch N Start El- JSL'.04 W: Upstream N.S. 551.10 ft i6ravity) Gravity flow at upend, Ct;JJ0.u0 ft) Trans dirt: ft ROUTE HYDROGRAPH 11 THROUGH REACH S 3.6683 cfs 4.4350 ac-ft 9.83 hrs 513.22 ft 3025.09 if `�/48rVm— tlis-Lcii-gzai ih d 1',"obii1=_i�li _ iiS 0C. Ir C. page 1 ROV I-1-Sr:,Y Pt`-1Rt:: 1 t a0YR 51—01^N ROUT 1NG H I S T'ORY OF i-41 I?>~:L]l�€:�E`1 r t� i l' T' Date of Session: 5f18i9s CLEARHIS ROUTE HYDR06RAPH 12 THROUGH REACH N2 Network N2 Reach (AREA> {Act 3i :L Full; X Gull Ndepth Qiam> Me!> CFVei) Carea W 29.67 8.75 (Ditch Reach) 0.37 4.24 OW HrrLINE H82 Hydraulic 6radeline for Reach H62 C-FROM-) <--TO--> CFLOW> floss Ent HGL EntLoss ExtLoss Outlet Inlet AppHead BndHead 3unHead HeadWtr -c6Jmh- ------ -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- Ditch W Start El: 516.97 W: Upstreaw W.S. 551.23 ft t6ravitvl GGravity flow at upend, i5sv.?a ft) Trans dirt: ft ROUTE HYDR06RAPH 12 THROUGH REACH S 8.6484 cfs 6.6667 ac-ft 9.17 hrs s13.48 ft 5620.74 cf 1 ATTACHMENTS FROM :14C SWM-GRTEWRYC20TH-FLR> TO :8P1G0999P2062S83S17 1996.0S-18 09:36PM g02S P.01/02 Date : May 14 ] 995 �'U• �Mr.. Kent Robirisc7n -------------_--------- FROM: David M. Hartley, Hydrologist , King Comity Surface Water Management REt ESTIMATE OF 100-YR FLOOD STAGE OF LAKE DESIRE The attached graph shown cstimateg of stage f.requenciem- at Lake De4i.rc based on modeling of lake hydrology with a continuous hydrologic model. using 42 years of precipitation data. Please note the following: x Stage; shown oTi the graph are relative to the uplstr-eam invert elevatioTI Of the 30-inch CMP c:ulvPrt where the equestrian Path crosser, the outlet channel of the, lake. The arbitrary stage assigned to this reference paint is 20 . 00 feet. 2 . Stage estimates depend on our approximate knowledge of lake. hathymetry and outlet hydraulics which arc observed to be c:onsiderab)y backwatered by the low-gradient outlet channel . 3 . The outlet hydraulics are subjccL to shifting control because of beaver dams acid other debris that are likely to raise 1eve1.� . These effects are not included in the model and can not be reliably predicted. Actual levels may be somewhat under flood conditions in the field. Please contact me at 296-8055 if you have any further questions about modeled stages. M"( 1 Past-W I-a)(Nole 7671 oMo paynt To Phone N . - S ,�- _ 1'IK+no w ��,�.. S S-- far,g D pAxN '�/li i 2 n7c7�n-•75B'�� r� l FROM WC SWM-GRTEWRYC20TH-FLR> TO :8P160999P2062583S17 1995.05-18 09:36PM #025 P.02/02 STAGE (INVERT OF OUTLET AT 20.0 FT) N �jNNNNNNNNNNNNtVNNiVNNN NNIVNNWWWWWWWWWW �A � �D '4b� ZD6 NW ACJt � �JOotDO � NW � Ut o r �..- c _ - -- m - - - -- (D M cn t c): m n 0 o o �� s � � � s i t-