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HomeMy WebLinkAboutDrainage ReportCERTIFICATION I certify that this revised report for the drainage design for the Greens Prairie Center -Phase I Detention Pond, was prepared by me in accordance with the provisions of the City of College Station Drainage Policy and Design Standards for the owners hereof. TABLE OF CONTENTS DRAINAGE REPORT -REVISED GREENS PRAIRIE CENTER, PHASE I -DETENTION POND CERTlFICA TION ................................................................................................................................................................. l TABLE OF CO TENTS ....................................................................................................................................................... 2 LIST OFT ABLES .................................................................................................................................................................. 2 INTRODUCTION .................................................................................................................................................................. 3 GENERAL LOCATION AND DESCIUPTION ................................................................................................................. 3 FLOOD HAZARD INFORMATION ................................................................................................................................... 3 DEVELOPMENT DRAINAGE PATTERNS ...................................................................................................................... 3 DRAINAGE DESIGN CIUTEIUA ....................................................................................................................................... 3 STORM WATER RUNOFF DETERMINATION .............................................................................................................. 4 DETENTION FACILITY DESIGN ..................................................................................................................................... 4 CONCLUSIONS ..................................................................................................................................................................... 6 APPENDIX A ......................................................................................................................................................................... 7 Time of Co11centratio11 Data & Calc11latio11s APPENDIX B ........................................................................................................................................................................ 10 Dete11tion Pond Design luformation EXHIBIT A ........................................................................................................................................................................... 32 Pre-Development Drainage Area Map -Dete11tio11 Po11d EXHIBIT B ........................................................................................................................................................................... 34 Post-Development Draillage Area Map -Detention Pond SHEET 1 OF 1 ...................................................................................................................................................................... 36 Dete11tio11 Pond Pfau & Details LIST 0 F TABLES TABLE 1 -Time of Concentration (tc) Equations .................................................................................. 4 TABLE 2 -Pre-& Post-Development Runoff Information -Detention Evalu ation .............................. 4 TABLE 3 -Pre-& Post-Development Peak Discharge Comparison -.................................................... 5 Discharge Point with Detention Pond TAB LE 4 -Summary of Maximum Pond Water Levels ......................................................................... 6 DRAINAGE REPORT -REVISED GREENS PRAIRIE CENTER, PHASE 1 -DETENTION POND INTRODUCTION The purpose of this revised report is to provide the hydrological effects of the construction of the Greens Prairie Center -Phase I Detention Pond, and to verify that it meets the requirements set forth by the City of Co ll ege Station Drainage Policy and Design Standards. GENERAL LOCATION AND DESCRIPTION The detention pond for this project will be located on the 1.66 acre tract, Lot 1, Block 1, Greens Prairie Center, located west of Arrington Road at its intersection with State Highway 40 and north of Greens Prairie Road in College Station, Texas. This report addresses the future development of Phase 1 and the adjacent area of this project. The site is predominantly wooded. The existing ground elevations range from Elevation 287 to Elevation 306. The general location of the project site is shown on the vicinity map in Exhibit A. FLOOD HAZARD INFORMATION The project site is located in the Spring Creek Tributary B Drainage Basin. The site is located in a Zone X Area according to the Flood Insurance Rate Map prepared by the Federal Emergency Management Agency (FEMA) for Brazos County, Texas and incorporated areas, Community No. 481195 and 480083, Panel No. 205D, Map No. 48041 C0205D, effective dated February 9, 2000. Zone X areas are determined to be outside of the 500-year floodplain. DEVELOPMENT DRAINAGE PATTERNS Prior to development, the storm water runoff in this area flows to two existing drainages which convey the runoff to the existing culverts under Greens Prairie Road and Arrington Road. The culverts discharge into an existing drainage which flows through Lot 1, Block 1, and then into the SH 40 right-of-way. The pre-development drainage area for the detention pond design is shown on Exhibit A. DRAINAGE DESIGN CRITERIA The design parameters for the stonn drainage analysis are as follows: • HEC-1 Program -Utilized to detem1ine peak storm water runoff rates for the detention facility design. A Type III rainfall distribution was used. • Design Storm Frequency Detention facility analysis 5, 10, 25, 50 and 100-year stom1 events • Runoff Curve Number (CN) -Detention Pond The Brazos County Soil Survey shows the soils in the area to be classified as hydrologic group D soils. The pre-development CN is based on no development on the site. The post-development CN is based on the future development of the project. The CN calculations are fou nd in Appendi x B. • Time of Concentration, tc -Calculations are based on the method found in th e TR-55 publication. Refer to Table I fo r the eq uations and Appendix A for calculations. The runoff fl ow path used for ca lculatin g the pre-development time o f concentrati on is shown on Exhibit A. S ince the post-development flow path for this development cannot be detem1ined at this time, it was assumed that the post-development Tc for the detention pond be 25 minutes. STORM WATER RUNOFF DETERMINATION The peak runoff values were detem1ined in accordance with the criteria presented in the previous section for the 5, 10, 25, 50, and 100-year storm events. The drainage area for the pre-development condition is shown on Exhibit A, and the post-development drainage area is shown on Exhibit B. Pre-and Post-development runoff conditions for the detention pond design drainage areas are summarized in Table 2. The pre-and post-development runoff information for the detention pond evaluation is shown in Table 3. TABLE 1 -Time of Concentration (tc) Equations The time of concentration was determined using methods found in TR -55, "Urban Hydrology for Small Watersheds. " The equations are as f ollows: Time of Concentration: For Sheet Flow: For Shallow Concentrated Flow: Tc = T1(shee1 llow) + T1(concenlra1ed sheel llow) where: T1 =Travel Time, minutes where: T1 =travel time, hours n =Manning's roughness coefficient L = flow length, feet P2 = 2-year, 24-hour rainfall = 4.5" s = land slope, ft/ft T1 = LI (60*V) where: T1 = travel time, minutes V =Velocity, fps (See Fig 3-1 , App. A) L = flow length , feet Refer to Appendix A for calculations. TABLE 2 -Pre-& Post-Development Runoff Information -Detention Evaluation (Revised) Area# Area CN tc Lag (acres) (min) (hrs) I Pre 100 26.84 79.5 35.4 0.354 -------· ----- Post 200 26.84 92.0 25.0 0.250 DETENTION FACILITY DESIGN The runoff from this development that drains to SH 40 and ultimately to Tributary B of Spring Creek must be detained to pre-development flow levels at the discharge point of the detention pond at th e SH 40 right-of-way line. The proposed detention pond facility will occup y all of Lot 1, Block 1, o f the Greens Prairie Center development. As shown on Sheet 1of1 , the Detention Pond Pl an and Detail s, most of th e runoff th at enters th e pond is through the existin g cul verts under Arrington Road and Greens Prairie Road . -1 A review of the drainage desi gn data for these culverts indicates they were designed fo r "developed" conditions upstream of the culverts. These culve rts appear to have adequate capacity to pass the post-development runoff into the proposed detention pond. Thi s should be verified when the land is developed. The pond outlet structure is a 5'x5' concrete riser structure wi th an invert Elevati on of 289.0, an 18" wide opening in the front of the structure from Elevation 289.0 to the top of the structure at Elevation 295.0. On each side and the rear of th e structure are 24" wide openings at Elevation 294.0. The discharge pipe is 42" HDPE pipe, 55 feet in length, with a concrete headwall at the downstream end of the pipe. The upstream invert elevation of the pipe is 288.9. Concrete riprap will be placed at the discharge end to control erosion. The pipe has a design slope of 1.0%. The top of the pond benn is at Elevation 297.0. The peak flow out of the detention faci lity was determined by the HEC-1 program using the depth discharge data for the pond outlet structure and the pond volume data as provided in Appendix B. As shown in Table 3, the post-development peak outflow at the di scharge point is less than the allowable peak outflow for the design stonn event. Additionally, Table 4 presents the maximum water surface in the pond for each storm event, as well as the amount of freeboard provided. The data shown in Tables 3 & 4 are from the HEC-1 computer model. The summary printout of the model is included in this report in Appendix B . A comparison of the pre-& post-development peak discharge values for the discharge point shows a decrease in the runoff for all storm events. The detention pond will reduce the peak runoff to less than or equal to the pre-development runoff, as the "Post-Development with Pond" data in Table 3 shows. TABLE 3 -Pre-& Post-Development Peak Discharge Comparison - Discharge Point with Detention Pond (Revised) Location Os 010 0 25 (cfs) (cfs) (cfs) Pre-Development Total@ Discharge Point 50 67 79 Post-Development without Pond Total@ Discharge Point 64 81 93 Post-Development with Pond Into Pond 60 81 93 Out of Pond 47 66 79 Decrease 3 1 0 Oso 0 100 (cfs) (cfs) 90 106 104 120 104 120 88 99 2 7 The area-capacity data and th e depth-discharge data for the detenti on pond are provided in Appendix B. The detention pond grading plan is shown on Sheet 1 of 1 of th e construction drawings TABLE 4 -Summary of Maximum Pond Water Levels (Revised) Storm Event Water Surface Freeboard, Elevation, ft. ft. 5-year 293.8 3.2 -----·-----10-year 294.5 2.5 --------25-year 294.9 2.1 . ---------------------50-year 295.2 1.8 ---·---------100-year 295.7 1.3 Note: Detention Pond Top of Berm Elevation = 297.0 CONCLUSIONS The construction o,f this project wi ll increase the storm water runoff from this site. The detention facility will reduce the post-development flow to the pre-development valu e. No flood damage to downstream or adj a cent landowners is expected as a result of thi s development. However, as the area develops and the plans for the development are fi nali zed, the assumptions utilized in this report need to be verified. APPENDIX A Time of Concentration Data & Calculations Greens Prairie Center -Phase 1 Pre-Development Time of Concentration Calculations Refer to Exhibit A for flow path locations. Drainage Area Nos. 100 Sheet Flow: n= P= L= .. ·~t 2 '61 \.'.ly,~~i Elev1= T,= 0.007(L *nt" = 0.468 hours= .... I __ 2_8_._1_m_i_n __ ~ (P)os*(S)o"' Concentrated Flow: V= ,·;k~:~,"~2';.jJ fps (unpaved) ' .... -~~fi...:T.,~~..t, L= Y.:r:·\ ~-J!P:, '.n65gj ~ ~,. ·" , .,;, ~.· "' i4 ' ~ ·~~e~~1t! Elev,= ·. JSlope= T,= U(60*V) = 5.2 min Ditch Flow: V= L= Elev,= T,= U(60*V) = 0.5 min Culvert Flow, Q=40cfs: V= L= Elev1= T,= U(60*V) = 0.3 min Ditch Flow. Q=60cfs V= L= ' ":~:~;~J~~~ §i "'.:<,f,_, I ~ Elev1= T,= U(60*V) = 1.5 min 35.6 min 0.015 0:0170 0!0.320 0.0110 ..... ..___ -..... ..___ CV a. 0 VI CV VI \_.. :::s 0 u \_.. QJ .µ .., ::i: 1-2 . 50 - .20 - . 10 .06 .04 - . 02 - .01 - .005 I 1 J ---J I J I I ' ' ' I J ' . 0 r ::..Q., L,_ 0 I 'b Q., ~~~I I I I I I 2 , ' I I 4 1 I I I I I I I 6 J I ' ' I Average velocity, ft/sec . . . ' I I I , I I 10 . - I I Fil(U~ l·l.-.\vcr.:ic~ vcl0<itic, fc-r c:o1limatinl( lr..avd time for ~hallow conccntral~d now. (2 10-V!-Tfl.-55. Second Ed .. June \98<il I 20 APPENDIXB Detention Pond Design Information I () SCS Curve Number Calculations Pond-Pre-Development Drainage Area -100 Area -Ac. sq. mi. 26.84 0.0419 Tc = 35.4 Lag = L = 0.6Tc = Land Use Open Space -Good Woods-Good Pasture-Good Streets Farmstead Abandoned Oil Well Pad Total -CN II 21 .2 min= Soil Type Area -Ac. D 1.14 D 17.50 D 4.92 D 1.48 D 1.00 D 0.80 26 .84 0.354 hrs Weighted CN II CN 80 77 80 98 86 89 3.4 50.2 14.7 5.4 3.2 2.7 79.5 SCS Curve Number Calculations Pond-Post Development Drainage Area -200 Area -Ac. sq. mi. 26.84 0.0419 Tc = 25.0 Lag = L = 0.6Tc = 15.0 min= 0.25 hrs Weighted Land Use Soil Type Area -Ac. CN II CN Open Space -Good Woods-Good Pasture-Good Streets Farmstead Commercial Total -CN II D D D D D D 2.80 1.01 1.01 1.48 1.00 19.54 26.84 80 77 80 98 86 95 8.3 2.9 3.0 5.4 3.2 69.2 92 .0 Greens Prairie Center Pond Area-Capacity Data with Proposed Contours V = H * {[A1+A2 + (A1*A2}111J3} V = volume, ft2 A = area, ft 2 H = difference in elevation, ft Detention Pond Area -Capacity Data Elevation Depth Area Area Volume Cumulative Volume (ft) (ft) (ft2) (acres) (ft3) (ft3) 289.00 0.00 0.00 0 0 0 290.00 1.00 1,452.87 0.0334 484.29 484.29 291.00 2.00 27,589.37 0.6334 11 ,791 .14 12,275.43 292.00 3.00 35,544.53 0.8160 31 ,483.08 43,758.51 293.00 4.00 38,500.87 0.8839 37,012.86 80,771.37 294.00 5.00 41,931 .35 0.9626 40,203.91 120,975.28 295.00 6.00 45,285.65 1.0396 43,597.75 164,573.03 296.00 7.00 49,256.76 1.1308 47,257.30 211,830.33 297.00 8.00 65,752.69 1.5095 57,306.53 269,136.86 90% 90% Cumulative Cumulative (ft3) (acre-ft) 0.00 0.00 435.86 0.01 11,047.89 0.25 39,382.66 0.90 72,694.23 1.67 108,877 .75 2.50 148,115.73 3.40 190,647.30 4.38 242,223.17 5.56 Greens Prairie Center -Phase 1 Detention Pond Elevation Discharge Data Elevation Discharge Data Front opening 18" wide 3-24" wide openings 42" Outlet Elevation Top= 295.0; Crest= 289.0 Top= 295.0; Crest= 294.0 Weir Weir (ft) y, depth (ft) Q, cfs1 y, depth (ft) Q,cfs 289.0 0 0 ---- 290.0 1 4.5 ----·---291 .0 2 12.7 ----.. 292.0 3 23.7 ----.. 293.0 4 36.0 ------------------294.0 5 50.0 -----------·-· . ----295.0 6 66.1 1 18.0 ---·-··-···--·-• 296.0 7 83.4 2 50.9 . ·--·-······-·-----• 297.0 8 101 .8 3 93.5 1. Weir Equation Q = 3.0 • L • y 312 2. Overflow Spillway -Mannings Equation • When the water level in the ponds exceeds Elevation 295.0, the allowable flow from the outlet structure exceeds the flow through the 42" outlet pipe, therefore, the 42" pipe controls the discharge. Pipe Q,cfs 0 6.2 -----·-21 .7 36.8 ------62.1 --------78.8 ---·· 92.4 ···---104.2 ------114.9 Overflow Spillway 10' BW, 4H:1V side slopes Crest = 296.0, n = 0.030 y, depth (ft) Q, cfs2 ---- ---- ---- ---- ---- ---- ---- 0 0 1.0 39.5 Total Discharge Elevation Q,cfs (ft) 0 289.0 4.5 290.0 12.7 29 1.0 23.7 292.0 36.0 293.0 50.0 294.0 84.1 295.0 104.2 • 296.0 154.4 • 297.0 Pre-Development HEC-1 S/N : 13 43001909 HMVersion: 6 .33 Data File: C:\WINDOWS\TEMP\-v bh3707.TMP PRE rw, •T ~W~********************************* *************************************** * * * rLOOD HYDROGRAPH PACKAGE (HEC-1) * * U.S. ARMY CORPS OF ENGINEERS * MAY 1991 * * HYDROLOGIC ENGINEERING CENTER * VERSION 4 .0.lE * * 609 SECOND STREET * * * DAVIS, CALIFORNIA 95616 * 2UN DATE 11/14/2006 TIME 15:16 :03 * * (916) 756-1104 * * * r ~w w w'*********************************** *************************************** x x xxxxxxx xxxxx x x x x x x xx x x x x x xxxxxxx xxxx x xxxxx x x x x x x x x x x x x x x xxxxxxx xxxxx xxx : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Full Microcomputer Implementation by Haestad Methods, Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 37 Brookside Road * Waterbury, Connecticut 06708 * (203) 755-1666 THI S PROG RAM REPLACES ALL PREVIOUS VERSIONS OF HEC-1 KNOWN AS HECl (JAN 73), HEClGS, HEClDB, AND HEClKW. THE DEFINITIONS OF VARIABLES -RTIMP-AND -RTIOR-HAVE CHANGED FROM THOSE USED WITH THE 1 973-STYLE INPUT STRUCTURE. THE DEFINI TI ON OF -AMSKK-ON RM-CARD WAS CHANGED WITH REVISIONS DATED 28 SEP 81. THIS IS THE FORTRAN 77 VERSION NEW OPT IONS : DAMBREAK OUTFLOW SUBMERGENCE , SINGLE EVENT DAMAGE CALCULATION, DSS:WRITE STAGE FREQUENCY, DSS :READ TIME SERIES AT DESIRED CALCULATION INTERVAL LOSS RATE:GREEN AND AMPT INFILTRATION KINEMATIC WAVE: NEW FINITE DIFFERENCE ALGORITHM HEC-1 INPUT PAGE 1 LINE ID ....... 1 ....... 2 ....... 3 ....... 4 ....... 5 ....... 6 ....... 7 ....... 8 ....... 9 ...... 10 1 ID Greens Prairie Center -Phase 1 2 IT 3 13NOV06 0 300 3 IO 5 0 4 JR PREC 11. 20 9.80 8.80 7.70 6.20 5 PG 1 6 KK DAlOO 7 KM Drainage Area 100 8 KO 22 9 BA .0419 10 IN 30 13NOV06 0 11 PC .005 .010 .015 .020 .025 . 031 .037 .043 .050 .057 12 PC .064 . 072 .081 . 091 .102 .114 .128 .146 .189 .217 13 PC .250 . 298 .500 .702 .750 .783 . 811 .834 .854 .872 14 PC .886 .898 .910 . 919 .928 .936 .943 .950 .957 .963 15 PC .969 .975 .981 .986 .991 . 996 1.000 16 LS 79.5 17 UD 0.354 18 zz ·.:./N: 1343001909 HMVersion: 6.33 Data File: C:\WINDOWS \TEMP\-vbh3707 .TMP TTT************************************** * ?LOOD HYDROGRAPH PACKAGE (HEC-1) * MAY 1991 VERSION 4.0 .lE * * * ?.U.i DATE 11/14/20 06 TIME 15: 16: 03 * * T**************************************** Greens Prairie Center -Phase 1 3 IO OUTPUT CONTROL VARIABLES IPRNT 5 PRINT CONTROL I PLOT 0 PLOT CONTROL QSCAL 0. HYDROGRAPH PLOT SCALE HYDROGRAPH TIME DATA NMIN 3 MINUTES IN COMPUTATION IDA TE 13NOV 6 STARTING DATE ITIME 0000 STARTING TIME INTERVAL NQ 300 NUMBER OF HYDROGRAPH ORDINATES J? JR NDDATE 13NOV 6 ENDING DATE NDTIME 1457 ENDING TIME I CENT 19 CENTURY MARK COMPUTATION INTERVAL TOTAL TIME BASE 0.05 HOURS 14.95 HOURS ENGLISH UNITS DRAINAGE AREA PRECIPITATION DEPTH LENGTH, ELEVATION FLOW STORAGE VOLUME SURFACE AREA TEMPERATURE MULTI-PLAN OPTION NP LAN MULTI-RATIO OPTION SQUARE MILES INCHES FEET CUBIC FEET PER SECOND ACRE-FEET ACRES DEGREES FAHRENHEIT 1 NUMBER OF PLANS RATI OS OF PRECIPITATION 11 .20 9.80 8.80 7 .7 0 6.20 *************************************** * * * U.S. ARMY CORPS OF ENGINEERS * * HYDROLOGIC ENGINEERING CENTER * * 609 SECOND STREET * * DAVIS, CALIFORNIA 95616 * * (916) 756 -1104 * * * *************************************** ••• ~~* *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** C· KO ************** * * * DAlOO * * ************** OUTPUT CONTROL VARIABLES IPRNT 5 PRINT CONTROL I PLOT 0 PLOT CONTROL HYDROGRAPH PLOT SCALE QSCAL 0. IPNCH IOUT ISAVl ISAV2 TIMINT 0 PUNCH COMPUTED HYDROGRAPH 22 SAVE HYDROGRAPH ON THIS UNIT 1 FIRST ORDINATE PUNCHED OR SAVED 300 LAST ORDINATE PUNCHED OR SAVED 0 .050 TIME INTERVAL IN HOURS OPSR.il.TION ;.:·;:::iROG RAPH AT PEAK FLOW AND STAGE (END-OF-PERIOD) SUMMARY FOR MULTIPLE PLAN-RATIO ECONOMIC COMPUTATIONS FLOWS IN CUBIC FEET PER SECOND, AREA IN SQUARE MILES STATION AREA DAlO O PLAN 0.04 TIME TIME TO PEAK IN HOURS RATIOS APPLIED TO PRECIPITATION RATIO 1 RATIO 2 RATIO 3 RATIO 4 RATIO 5 11. 20 9 .80 8.80 7 .70 6.20 1 FLOW 106. 90. 79. 67. 11. 55 11. 55 11. 60 11. 60 11. 60 ••• NORMAL END OF HEC-1 *** 50 . Post-Development HEC-1 :-0/N: 1343001909 HMVersion: 6 .33 Data File: C:\WINDOWS \TEMP \-vbhlB24.TMP POND ~~ ~··•*********************************** *************************************** * * * rLOOD HYDROGRAPH PACKAGE (HEC-1 ) * * U.S. ARMY CORPS OF ENGINEERS * MAY 1991 * * HYDROLOGIC ENGINEERING CENTER * VERS I ON 4.0.lE * * 609 SECOND STREET * * * DAVIS, CALIFORNIA 95616 * RU~ DATE 11/14/2006 TIME 15:11:26 * * (916) 756-1104 * * * * ••• 4. -~********************************** *************************************** x x xxxxxxx xxxxx x x x x x x xx x x x x x xxxxxxx xxxx x xxxxx x x x x x x x x x x x x x x xxxxxxx xxxxx xxx : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : Full Microcomputer Implementation by Haestad Methods, Inc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 37 Brookside Road * Waterbury, Connecticut 06708 * (203 ) 755-1666 THIS PROGRAM REPLACES ALL PREVI OUS VERSIONS OF HEC-1 KNOWN AS HECl (JAN 73), HEClGS, HEClDB , AND HECl KW . THE DE FINITIONS OF VARIABLES -RTIMP-AND -RTIOR-HAVE CHANGED FROM THOS E USED WITH THE 1973-STYLE INPUT STRUCTURE. THE DEFINITION OF -AMSKK-ON RM-CARD WAS CHANGED WITH REVI SIONS DATED 28 SEP 81 . THIS IS THE FORTRAN?? VERSION NEW OPTIONS : DAMBREAK OUTFLOW SUBMERGENCE , SINGLE EVENT DAMAGE CALCULATION, DSS :WRITE STAGE FREQU ENCY , DSS :READ TIME SERIES AT DESIRED CALCULATI ON INTERVAL KINEMATIC WAVE: NEW FINITE DIFFERENCE ALGORITHM LOSS RATE:GREEN AND AMPT INFILTRATION HEC-1 INPUT PAGE 1 LINE ID ....... 1 ....... 2 ....... 3 ....... 4 ....... 5 ....... 6 ....... 7 ....... 8 ....... 9 ...... 10 1 ID Greens Prairie Center -Phase 1 2 IT 3 13NOV06 0 300 3 IO 5 0 4 JR PREC 11 . 20 9.80 8 .80 7 .70 6.20 5 PG 1 6 KK DA200 7 KM Drainage Area 200 8 KO 22 9 BA .0419 10 IN 30 13NOV06 0 11 PC .005 .010 .015 .020 .025 .031 .037 .043 .050 .057 12 PC .064 . 072 .081 .091 .102 .114 .128 .146 .189 .217 13 PC .250 . 298 .500 .702 .750 .783 . 811 .834 . 854 .872 14 PC .886 .898 . 910 . 919 .928 .936 . 943 .950 .957 .963 15 PC . 969 .975 .981 .986 .991 . 996 1 .000 16 LS 92. 0 17 UD 0.25 18 KK Pond 19 KM Detention Pond -Phase 1 20 KO 22 21 RS l ELEV 289.00 22 SV 0 0.01 0.25 0.90 1.67 2.50 3.40 4.38 5.56 23 SE 289 .0 290.0 291.0 292.0 293.0 294.0 295.0 296 .0 297.0 24 SQ 0 4.5 12.7 23 .7 36 .0 50 .0 84.1 104.2 154. 4 25 SE 289.0 290.0 291.0 292.0 293.0 2 94. 0 295.0 296 .0 297 .0 26 zz ~5Cl S/N : 13 43001909 HMVersion : 6.33 Data File: C:\WINDOWS\TEMP\-vbhlB24.TMP ~~•T**~********************************** * "LOOD HYDROGRAPH PACKAGE (HEC-1) * MAY 1991 * VERSION 4.0 .lE * * R.1Jc' DATE 11/14 /2006 TIME 15: 11: 26 * * ·~~~~~•********************************** Greens Prairie Center -Phase 1 ' IO OUTPUT CONTROL VARIABLES IPRNT 5 PRINT CONTROL I PLOT 0 PLOT CONTROL QSCAL 0. HYDROGRAPH PLOT SCALE HYDROGRAPH TIME DATA NMIN 3 MINUTES IN COMPUTATION INTERVAL IDA TE 13NOV 6 STARTING DATE ITIME 0000 STARTING TIME NQ 300 NUMBER OF HYDROGRAPH ORDINATES .::R NDDATE 13NOV 6 ENDING DATE NDTIME 1457 ENDING TIME I CENT 19 CENTURY MARK COMPUTATION INTERVAL TOTAL TIME BASE 0.05 HOURS 14.95 HOURS ENGLISH UNITS DRAINAGE AREA PRECI PITATION DEPTH LENGTH, ELEVATION FLOW STORAGE VOLUM E SURFACE AREA TEMPERATURE MULTI-PLAN OPTION NP LAN MULTI-RATIO OPTION SQUARE MILES INCHES FEET CUBIC FEET PER SECOND ACRE-FEET ACRES DEGREES FAHRENHEIT 1 NUMBER OF PLANS RATIOS OF PRECIPITATION 11.2 0 9 .80 8.80 7 .70 6.20 *************************************** * * * U.S. ARMY CORPS OF ENGINEERS * * HYDROLOGIC ENGINEERING CENTER * * 609 SECOND STREET * * DAVIS, CALIFORNIA 95616 * * (916) 756-1104 * * * *************************************** T~T *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ************** * * o KK * DA200 * * * ************** OUTPUT CONTROL VARIABLES IPRNT 5 PRINT CONTROL I PLOT 0 PLOT CONTROL QSCAL 0. HYDROGRAPH PLOT SCALE IPNCH 0 PUNCH COMPUTED HYDROGRAPH IOUT 22 SAVE HYDROGRAPH ON THIS UNIT ISAVl 1 FIRST ORDINATE PUNCHED OR SAVED ISAV2 300 LAST ORDINATE PUNCHED OR SAVED TIMINT 0.050 TIME INTERVAL IN HOURS ~~* ~** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** :: 0 c:o ************** * * Pond * * * ************** OUTPUT CONTROL VARIABLES IPRNT I PLOT QSCAL IPNCH IOUT ISAVl ISAV2 TIMINT 5 PRINT CONTROL 0 PLOT CONTROL 0 . HYDROGRAPH PLOT SCALE 0 PUNCH COMPUTED HYDROGRAPH 22 SAVE HYDROGRAPH ON THIS UNIT 1 FIRST ORDINATE PUNCHED OR SAVED 300 LAST ORDINATE PUNCHED OR SAVED 0.050 TI ME INTERVAL IN HOURS <.:Y::JROGRAPH AT ?OUTED TO PEAK FLOW AND STAGE (END-OF -PERIOD) SUMMARY FOR MULTIPLE PLAN-RATIO ECONOMIC COMPUTATIONS FLOWS IN CUBIC FEET PER SECOND, AREA IN SQUARE MILES TIME TO PEAK IN HOURS RATIOS APPLIED TO PRECIPITATION STATION AREA PLAN RATIO 1 RATIO 2 RATIO 3 RATIO 4 RATIO 5 11. 20 9.80 8.80 7.70 6 .20 DA200 0.04 1 FLOW 120 . 104. 93. 81 . TIME 11. 50 11. 50 11. 50 11. 50 11. 50 Pond 0 .04 1 FLOW 99. 88. 79. 66. 47 . TIME 11. 70 11. 70 11.70 11. 70 11. 75 ** PEAK STAGES IN FEET ** 1 STAGE 295 .74 295 .20 294.85 294.47 293.79 TIME 11. 70 11 . 70 11. 70 11. 70 11. 75 · ·· ~ORMAL END OF HEC-1 *** 64 . EXHIBIT A Pre-Development Drainage Area Map -Detention Pond EXHIBIT B Post-Development Drainage Area Map -Detention Pond SHEET 1OF1 Detention Pond Plan & Details