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HomeMy WebLinkAbout2005-01-12 Preliminary Storm Drainage Analysis ReportPRELIMINARY STORM DRAINAGE ANALYSIS REPORT FOR WAL-MART STORE #1861-01 5815 Nora Avenue North Oak Park Heights, MN Prepared by: McCombs Frank Roos Associates, Inc. 15050 23 Avenue North Plymouth, MN 55447 (763) 476-6010 January 2005 \- • ' ryfN, (2-1 PRELIMINARY STORM DRAINAGE A \ALYSIS REPORT FOR WAL4VIART STORE #1861 -01 CITY OF OAK PARK HEIGHTS Prepared By: Brady Busselman and Erik Miller, P.E. 1 hereby certify that this report was prepared by me or under my direct supervision and that I am a duly Licensed Professional Engineer under the laws of the State of Minnesota. Date Erik W. Miller, P.E Minnesota Reg. No. 41326 TABLE OT CONTENTS I. EXECUTIVE SUMMARY SITE LOCATION DESIGN CRITERIA PROPOSED DRAINAGE SYSTEM CONCLUSION IL STORMWATER DRAINAGE REPORT PRE - EXPANSION POST- EXPANSION Page # 1 1 2 2 3 3 IIIo DRAINAGE ANALYSIS SUBCATCHMENT DESCRIPTIONS 4 PEAK RUNOFF CONTROL /STORMWATER FLOW VOLUME 5 WATER Q UALITY 6 DOWNSTREAM WATER LEVEL 6 CONVEYANCE 6 100 -YEAR FLOOD /OVERFLOW CONDITION 8 IV. EROSION CONTROL 8 FIGURES FIGURE A FIGURE B FIGURE C FIGURE D FIGURE E - FIGURE F - FIGURE G FIGURE H - LOCATION MAP - WATERSHED MAP -- PRE - EXPANSION HYDROCAD REPORTS -- PRE - EXPANSION HYDROCAD MAP POST - EXPANSION HYDROCAD REPORTS POST - EXPANSION HYDROCAD MAP - STORM SEWER 10 -YEAR EVENT SPREADSHEET - STORM SEWER DRAINAGE AREAS MAP Preliminary Storm Drainage Analysis Wal-Mart Stores #1861 -01 Oak Park Heights, Minnesota January 12, 2005 Page 1 I. EXECUTIVE SUMMARY SITE LOCATION The 18 acre site in the City of Oak Park Heights is currently occupied by an approximately 98,000 SF building and an approximately 10 acre parking lot (Figure A). The site is bounded on the west by Norell Avenue North, on the south by 58 Street North, on the north by Highway 36, and by undeveloped land on the east. The proposed expansion will take place on a 6.3 -acre parcel of undeveloped land to the east of the existing site. The proposed expansion will add approximately 109,000 SF to the building and approximately 3 acres to the parking lot. A proposed extension of Novak Avenue North will also take place on the 6.3 -acre parcel. This extension will add approximately 0.5 acres of impervious surface. DESIGN CRITERIA This project is located in the Brown's Creek Watershed District, which requires that an applicant for a stormwater management permit demonstrate: (a) That peak runoff rate of the proposed conditions does not exceed that of the existing conditions for the 1.5 -year, 10 -year, and 100 -year 24 -hour storm events. (b) That stormwater flow volume from the site for a 1.5 -year, 24 -hour event will not increase. (c) At the downgradient property boundary, there will not be an increase in total suspended solids, total nitrogen or heavy metals, or contribute to a stormwater phosphorus concentration that exceeds the inflow concentration indicated in "Brown's Creek Watershed District Rules" Appendix 2.2. (d) That there will not be an increase in the bounce in water level or duration of inundation, during a precipitation event of critical duration with a return frequency of 1.5, 10, or 100 years in the subwatershed drainage area in which the Preliminary Storm Drainage Analysis Wal-Mart Stores #1861 -01 Oak Park Heights, Minnesota January 12, 2005 Page 2 site is located, for any downstream lake or wetland beyond the limit specified in Appendix 2.3 of "Brown's Creek Watershed District Rules" for the lake or wetland susceptibility class. To meet these requirements, Hydrocad software has been used for analysis. This program effectively models runoff conditions using Soil Conservation Service TR -20 method. Runoff curve numbers were estimated from open area, impervious area and the hydrologic soil group as determined from on -site soil classifications. PROPOSED DRAINAGE SYSTEM The proposed on -site drainage system will consist of curb and gutter, catch basins, storm sewer pipes and three detention ponds. Runoff will be stored in ponds on site before being discharged into the existing public storm sewer. system. CONCLUSION The proposed stormwater management system has been designed to meet the City of Oak Park Height's and Brown's Creek Watershed District's stormwater management criteria and to be consistent with sound engineering practice. No significant adverse impacts to the existing stormwater management system are expected as a result of the proposed development. Preliminary Storm Drainage Analysis WaI -Mart Stores #1861 -01 Oak Park Heights, Minnesota January 12, 2005 Page 3 II. STORMWATER DRAINAGE REPORT PRE- EXPANSION This site is part of Brown's Creek Watershed District (Figure B). Runoff currently exits the site through a network of catch basins and storm sewer pipes. These pipes drain to the west, across Norell Avenue North and empty into a stonnwater pond on the west side of the street. Runoff enters the public storm sewer system from this pond. The proposed expansion area to the east is currently grassland. Predominant soil types on site consist of: Poorly graded sand (SP), poorly graded sand with silt (SP -SM), silty sands (SM), clayey sands (SC), and silt (ML). Based on the predominant soil types and a soil survey of the area, Hydrologic soil group B was used for this analysis. The estimated weighted CN for the site is 82 (Figure C). There are no streams, rivers, public waters or wetlands present on the site. POST - EXPANSION The proposed improvements consist of an approximately 109,000 SF building expansion, an approximately 13 acre parking lot, a future gas station and two stormwater detention ponds. The remainder of the site will be green space. After development, the estimated weighted CN will increase to 91 (Figure E). The proposed drainage concept for the site is to collect stormwater in catch basins and convey runoff from the new impervious area to three detention ponds. The detention ponds have been sized to retain stormwater runoff from the entire site while minimizing the discharge rate to the public storm sewer system. Preliminary Storm Drainage Analysis Wal -Mart Stores #1861.01 Oak Park Heights, Minnesota January 12, 2005 Page 4 III. DRAINAGE ANALYSIS SUBCATCHMENT DESCRIPTION For the purpose of ponding analysis, the site has been divided into three separate subcatchments (Figure F). The north subcatchment consists of approximately 13.7 acres, including parking lot, gas station, Norell Avenue North and areas of open space. The north subcatchment continues to use the existing storm sewer system located near the center of the parking lot. This system drains across Norell Avenue North, directly into the existing stormwater pond. The central subcatchment consists of approximately 2.5 acres, including a portion of the parking lot, the central Norell Avenue North entrance and areas of open space. The central subcatchment drains to the central pond on the west side of the site. The south subcatchment consists of approximately 8.8 acres including building roof drains, parking lot and areas of open space. The south subcatchment drains into the southern pond, located at the southwest corner of the site. Approximately 0.5 acres of the Novak Avenue North extension will be drained to the existing stormwater pond immediately south of Applebee's. This pond was constructed as part of the Applebee's sitework and, in addition to runoff from the Applebee's parking lot, receives runoff from the undeveloped land to the south and east, included the 6.3 -acre expansion area. Along with the 0.5 acres of the Novak Avenue North extension, runoff from approximately 0.6 acres of open space from the 6.3 -acre expansion area will continue to drain to the pond. Runoff from the rest of the 6.3 -acre expansion area will be drained to one of the three ponds to the west. Since this pond will experience a net loss of contributing area, it is our opinion that it will continue to function within its current design capacity. Proposed Conditions Subcatchment Area Hydrologic Soil Group Weighted CN TC North 13.65 AC B 89 21.2 min Central 2.45 AC B 87 10 min South 8.84 AC B 94 15 min Existing /Proposed Peak Runoff Rates Event Existing Proposed 1.5 -year _ 0.16 cfs 0 cfs 10 -year 4,07 cfs 3.25 cfs 100 -year 5.50 cfs 3.94 cfs Preliminary Storm Drainage Analysis Wal -Mart Stores #1861 -01 Oak Park Heights, Minnesota January 12, 2005 Page 5 PEAK RUNOFF CONTROJJSTORMWATER FLOW VOLUME Brown's Creek Watershed District Rules require that the peak runoff rate of the proposed conditions does not exceed that of the existing conditions for the 1.5 -year, 10-year, and 100 -year storm events. Brown's Creek Watershed District Rules also require that the stormwater flow volume leaving the site for a 1.5 -year 25 -hour event does not increase. Both requirements are met by using a series of three detention ponds along the west side of the site. For this analysis, Hydrocad software was used to model the ponds. (Figures C and E). A basic summary of inputs and results is as follows: Table 1 Rainfall Event 1.5 -year 10 -year 100 -year 24 -Hour Event 2.5' 4.15" 5.9" Table 2 Existing Conditions Area 19.37 AC Hydrologic Soil Grou B 8 IMMO 2 Table 3 Table 4 Preliminary Storm Drainage Analysis Wal -Mart Stores #1861 -01 Oak Park Heights, Minnesota January 12, 2005 Page 6 WATER QUALITY Brown's Creek Watershed District Rules require that at the downgradient property boundary, there will not be an increase in total suspended solids, total nitrogen or heavy metals, or contribute to a stormwater phosphorus concentration that exceeds the inflow concentration indicated in "Brown's Creek Watershed District Rules" Appendix 2.2. To provide water quality treatment, the ponds have been designed in accordance with NTJRP standards and to retain a 2.5" rainfall event below the NWL. DOWNSTREAM WATER LEVEL Brown's Creek Watershed District Rules require that there will not be an increase in the bounce in water level or duration of inundation, during a precipitation event of critical duration with a return frequency of 1.5, 10, or 100 years in the subwatershed drainage area in which the site is located, for any downstream lake or wetland beyond the limit specified in Appendix 2.3 of "Brown's Creek Watershed District Rules" for the lake or wetland susceptibility class. Based on conversations with the City's engineering consultant, runoff discharged from the existing stormwater pond drains to a city pond, not a lake or wetland. It is our opinion that this requirement does not pertain to the proposed development. CONVEYANCE Runoff from the north subcatchment is collected in a series of catch basins (Figures H and I) that consists, for the most part, of existing structures. Additional runoff created from the parking lot expansion will be picked up by adding two catch basins to the east Preliminary Storm Drainage Analysis Wal -Mart Stores #1861 -01 Oak Park Heights, Minnesota January 12, 2005 Page 7 side of the parking lot. These structures will drain to the existing storm sewer line. Another new structure will be needed on the west side of the parking lot. This structure will be constructed over the existing storm line. This storm sewer line will continue to drain into the existing pond on the west side of Norell Avenue North. Runoff from the central subcatchment is collected in two catch basins located in the parking lot on the west side of the building. From there the storm sewer line runs west and drains into the central pond. Runoff from the south subcatchment is collected in a series of structures beginning at the northeast corner of the building. The storm sewer line runs south, then west along the back of the building where it collects runoff from the roof drains. These structures drain into the pond at the southwest corner of the site. Due to grading constraints, runoff from the Novak Avenue North extension will be drained to the existing pond south of Applebee's. Since the net area draining to this pond is decreasing as a result of the Wal -Mart building and parking lot expansion, no additional capacity will be needed. Each of the three ponds is sized to store runoff from a 1.5 -year event. For storm events greater than the 1.5 -year event, water will exit the two new ponds through skimmer structures. The southern pond drains into the central pond, which drains into the existing pond. The outlet pipe of the existing pond will need to be fitted with an 8" orifice to limit discharge to pre - expansion rates. The existing pond will continue to discharge into the public storm sewer system to the north. Preliminary Storm Drainage Analysis Wal -Mart Stores #1561 -01 Oak Park Heights, Minnesota January 12, 2005 Page 8 100 -YEAR FLOOD /OVERFLOW CONDITION The three on -site detention ponds are designed to contain a 100 -year flood event while limiting discharge rates to existing conditions. In the case of a storm event larger than the 100-year, designated overflow routes will direct the storm water downstream to the public storm sewer system, bypassing the proposed ponds. Parking lot overflows and ponding freeboard have been provided to minimize the downstream impacts of this event. W. EROSION CONTROL All erosion and sediment control measures shall be in accordance with the MPCA general permit authorization to discharge storm water associated with construction activity, and Wal- Mart's guidelines. Erosion and sedimentation control measures to be employed during construction will most likely consist of: silt fence, inlet sediment filter, temporary sedimentation ponds, rock construction entrances, diversion ditches with check dams, and erosion blankets. Permanent erosion and sedimentation control measures include seeding, sodding, and landscaped open space areas, and permanent storm water ponds. Detailed erosion and sedimentation control plans will be completed as part of the final construction documents. FIGURE A 58th S 2 .4( w. Tower Dr W 2 "-, z 0 56th St N - o 55th St N z FIGURE B Property Lines DNR Water Bodies Brown's Creek WD Middle St Croix WMO III Valley Branch WD 0,5 0 0.5 1 Miles FIGURE C A Existin � Pond Existing Subcatchment ca Drainage Diagram for WAL14918 EXISTING Prepared by Brady Busselman - MFRA 1/10/2005 HydroCAD® 7.00 s/n 000887 ©1 986.2003 Applied Microcomputer Systems WAL14918 Ex1STING Type 1/ 24 -hr 1.5-YR Rainfall=2.50" Prepared by Brady Busselman - MFRA ' Page 2 H droCAD® 7.00 s/n 000887 © 1986 - 2003 A. r lied Microcom • uter S stems 1/10/2005 Time span =0.00 -48.00 hrs, dt =0.01 hrs, 4801 points Runoff by SCS TR -20 method, U H =SCS Reach routing by Stor -Ind +Trans method - Pond routing by Stor -Ind method Subcatchment EX -S: Existing Subcatchment Runoff Area =19.370 ac Runoff Depth =1.00" Flow Length =1 ,480' Tc =11.0 min CN =82 Runoff =28.57 cfs 1.611 af Pond EX -Po Existing Pond Peak Elev=933.53' Storage= 1.578 af Inflow =28.57 cfs 1.611 af 12.0" x 87.0' Culvert Outflow =0.16 cfs 0.150 af Total Runoff Area = 19.370 ac Runoff Volume ®1.611 af Average Runoff Depth = 1.00" WAL14918- EXISTING Prepared by Brady Busselman - MFRA H droCAD® 7.00 sin 000887 © 1 986 -2003 As shed Microcom Subcatchment EX -S: Existing Subcatchment Runoff = 28.57 cfs a@ 12.03 hrs, Volume= 1.611 af, Depth= 1.00" Runoff by SCS TR-20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt = 0.01 hrs Type 11 24 -hr 1.5 -YR Rainfall= 2.50" Area ac CN Description Length Slope Velocity Capacity Description min feet ft /ft ft/sec cfs Tc 7.6 32 30 28 26 24 22 20 18 16 u., 14 12 10 8 11.230 8.140 1 9.370 82 Weighted Average 6 4 2 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 260 0.0010 3.4 1,200 0.0050 Type 11 24 1.5 Rainfall =2.50" Page 3 uter S stems 1/10/2005 0.6 Sheet Flow, Roof Smooth surfaces n= 0.011 P2= 4.10" 5.9 29.00 Circular Channel (pipe), From far east roof drain. Diam= 30.0" Area= 4.9 sf Perim = 7.9' r= 0.63' n= 0.013 11.0 1,460 Total Subcatchment EX -S: Existing Subcatchment Hydrograph 28.57 cfs Rainfall- 2:5U!" RunoffAreal9 370 ac RunoffVo1ume1 611 af Runoff Depthl 00" Flow Leak t 0' Tc 000 ;#4 in AelaZimzer Alrarizof 0 2 4 6 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Q Runoff WAL14918 EXISTING Type 11 24-hr 1.5 -YR Rarnfa11=2.50" Prepared by Brady Busselman - MFRA Page 4 HydroCAD® 7.00 s/n 000887 © 1986 -2003 Applied Microcomputer Systems 1/10/2005 Inflow Area = 19.370 ac, Inflow Depth = 1.00" for 1.5 --YR event Inflow = 28,57 cfs @ 12,03 hrs, Volume= 1.611 af Outflow = 0.16 cfs @ 24.17 hrs, Volume= 0.150 af, Atten= 99 %, Lag= 728.3 min Primary = 0.16 cfs a@ 24.17 hrs, Volume= 0.150 of Routing by Stor -1 nd method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Peak Elev= 933.53' @ 24.17 hrs Surf.Area = 0.770 ac Storage= 1.578 af Plug - Flow detention time 1,114.0 min calculated for 0.150 af (9% of inflow) Center -of -Mass det. time 961.8 min ( 1,812.0 - 850.3 ) # Invert Avail.Stora.e Stora•e Descri•tion 931.00' # Routing 1 Primary Pond EX -P: Existing Pond 9.015 af Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store feet acres ) (acre-feet) (acre-feet 931.00 0.480 0.000 0.000 932.00 0.583 0.532 0.532 933.00 0.696 0.640 1.171 934.00 0.836 0.766 1.937 935.00 0.944 0.890 2.827 936.00 1.058 1.001 3.828 937.00 1.175 1.117 4.944 938.00 1.295 1.235 6.179 939.00 1.416 1.356 7.535 940.00 1.543 1.480 9.015 Invert Outlet Devices 933.30' 12.0" x 87.0' long Culvert RCP, end - section conforming to fill, Ke= 0.500 Outlet Invert= 932.87' S= 0.0049 '1' n= 0.013 Cc= 0.900 Primary OutFlow Max=0.16 cfs @ 24.17 hrs HW= 933.53' (Free Discharge) t--1- Culvert (Barrel Controls 0.16 cfs © 1.8 fps) WALL 491 8 -EX ST1 N G Prepared by Brady Busselman MFRA H droCAD® 7.00 sin 000887 © 1986 -2003 A • 32: 30 r 287. 26 24-: 22 20 1 8w . 14- 12..• low' 8� 6= 2 0 28.57 cfs Pond EX -P: Existing Pond Hydrograph lied Microcom uter S stems • Type 11 24 -hr 1.5 -YR Rainfall= 2.50" Page 5 1/10/2005 r ea- ()rag v= 933.53 af ulvert 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Inflow 0 Primary WALT 491 8 -EX ST!NG Type 11 24-hr 10 -YR Rainfal1=4.15" Prepared by Brady Busselman - MFRA Page 1 H droCAD® 7.00 s/n 000887 © 1986 -2003 A• •lied Microcom • uter S stems 1/10/2005 Time span =0.00 -48.00 hrs, dt =0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH =SCS Reach routing by Stor -Ind +Trans method - Pond routing by Stor -Ind method Subcatchment EX -S: Existing Subcatchment Runoff Area = 19.370 ac Runoff Depth =2.33" Flow Length = 1,460' Tc =11.0 min CN=82 Runoff =66,92 cfs 3.764 of Pond EX -PQ Existing Pond Peak Elev=935.63' Storage =3.463 af Inflow =66.92 cfs 3.764 af 12.0" x 87.0' Culvert Outflow=4.07 cfs 3.679 af Total Runoff Area = 19.370 ac Runoff Volume = 3J64 af Average Runoff Depth = 2.33" WALL 491 8 - EXISTING Prepared by Brady Busselman - MFRA H droCAD® 7.00 sin 000887 © 1 986 -2003 A. •lied Microcom Subcatchment EX -S: Existing Subcatchment Runoff = 66.92 cfs @ 12.03 hrs, Volume= 3.764 af, Depth= 2.33" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 10 -YR Rainfall =4.15" Area ac CN Description 11.230 8.140 61 >75% Grass cover, Good, HSG B 19.370 82 Weighted Average 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description min feet ftift ft /sec cfs 7.6 260 0.0010 3.4 1,200 0.0050 11.0 1,460 Total 70- 65- 601 55- , 50; 45-; N 3 40 o 35 EC 30y 25N 20- 15 107: 5- 0 0 Subcatchment EX -S: Existing Subcatchment Hydrograph • s - 66 92 cf 0.6 Sheet Flow, Roof Smooth surfaces n= 0.011 P2= 4.10" 5.9 29.00 Circular Channel (pipe), From far east roof drain. Diam= 30.0" Area 4.9 sf Perim= 7.9' r= 0.63' n= 0.013 e 1124 -11 RainfaII -' unofF Area =19.370 ac Hoff '; VoIume3 764 of Th noff Depth 33" F low Lengthl ,460 Tc11 0 min N =82 Type 11 24-hr 1O -YR Rainfall =4.15" Page 2 uter S stems 1110/2005 1, 0 4 , 10 , 7ArzerA .,_ APAWASTeAfr:Zfdf/aNsmi.------- 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Runoff WAL14918 EXISTING Type 11 24-hr 1O -YR Rainfall =4.15" Prepared by Brady Busselman - MFRA Page 3 H droCAD® 7.00 s/n 000887 © 1986 -2003 A* 'lied Microcom • uter S stems 1/10/2005 931.00' # Routin9 1 Primary Pond EX -P: Existing Pond Inflow Area = 19.370 ac, Inflow Depth = 2.33" for 10 -YR event Inflow = 66.92 cfs a@ 12.03 hrs, Volume= 3164 of Outflow = 4.07 cfs J 13.15 hrs, Volume= 3.679 af, Atten= 94 %, Lag= 67.4 min Primary = 4.07 cfs r@ 13.15 hrs, Volume= 3.679 of Routing by Stor -Ind method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Starting Elev= 933.30' Surf.Area= 0.738 ac Storage= 1.401 af Peak Elev= 935.63' a( 13.15 hrs Surf.Area= 1.016 ac Storage= 3.463 af (2.062 af above start) Plug -Flow detention time 602.5 min calculated for 2.278 af (61 % of inflow) Center -of -Mass det. time 309.4 min ( 1,135.1 - 825.8 ) # Invert Avail.Stora r e Stora. e Descri.tion 9.015 af Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store lfeet) (acres) (acre -feet) (acre -feet) 931.00 0.480 0.000 0.000 932.00 0.583 0.532 0.532 933.00 0.696 0.640 1.171 934.00 0.836 0.766 1.937 935.00 0.944 0.890 2.827 936.00 1.058 1.001 3.828 937.00 1.175 1.117 4.944 938.00 1.295 1.235 6.179 939.00 1.416 1.356 7.535 940.00 1.543 1.480 9.015 Invert Outlet Devices 933.30' 12.0" x 87.0' long Culvert RCP, end - section conforming to fill, Ke= 0.500 Outlet Invert= 932.87' S= 0.0049 '1' n= 0.013 Cc= 0.900 Primary OutFlow Max =4.07 cfs @ 13.15 hrs HW= 935.63' (Free Discharge) L1= Culvert (Barrel Controls 4.07 cfs © 5.2 fps) WAL'1 491 8 - EXISTING Prepared by Brady Busselman MFRA M droCAD® 7.00 s/n 000887 © 1986-2003 As 'lied Microcom 70 65 60 55 50 r 45 N u 40 a 35 30 25 20 15 10 5 uter S stems Pond EX -P: Existing Pond Hydrograph Type 11 24-hr 1 O -YR Ralnfatl= e 15" Page 4 1/10/2005 '00 40 Agear 0 eie; rafffirpffpg! . 01 - 0 f r:/,' 7: r ," f 7, 7,9 r a roMPIESEVAri reelffiNff n $4052 i F E + 0 2 4 6 1 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 inflow 0 Primary WALT 491 8- EXIST1 NG Prepared by Brady Busselman - MFRA H droCAD® 7.00 sin 000887 © 1986 - 2003 A Type 11 24 100 - YR Rainfall =5.99" Page 1 lied Microcom. uter S stems 1/10/2005 Time span= 4.40-48.00 hrs, dtw0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH =SCS Reach routing by Stor -Ind +Trans method - Pond routing by Stor -Ind method Subcatchment EX -S: Existing Subcatchment Runoff Area =19.370 ac Runoff Depth=3.90" Flow Length =1 ,460' Tc =11.0 min CN=82 Runoff =110.11 cfs 6.288 of Pond EX -Po Existing Pond Peak EIev= 937.09' Storage= 5.060 af Inflow =11 0.11 cfs 6.288 af 12.0" x 87.0' Culvert Outflow=5.50 cfs 6.188 af Total Runoff Area = 19.370 ac Runoff Volume = 6.288 af Average Runoff Depth = 3.90" WALI49I8- EXISTING Prepared by Brady Busselman - MFRA H droCAD® 7.00 s/n000887 © 1980 -2003 A 11 Runoff -- 110.11 cfs 12.02 hrs, Volume= 6.288 af, Depth= 3.90" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 100 -YR Rainfall= 5.90" Area ac CN Description 11.230 8.140 61 >75% Grass cover, Good, HSG B 19.370 82 Weighted Average Tc Length Slope Velocity Capacity Description min feet ftlft ft/sec cfs 7.6 260 0.0010 0.6 Sheet Flow, Roof Smooth surfaces n= 0.011 P2= 4.10" 3.4 1,200 0.0050 5.9 29.00 Circular Channel (pipe), From far east roof drain. ........ ...... . Diam= 30.0" Area 4.9 sf Perim= 7.9' r= 0.63' n= 0.013 .............. . 11.0 1,460 Total 120, 115, 1107 105- 100- 95. 90 85-; 80w 75- 70 . 60 . L T 55- 50' ��: 45 404 35 304 25I 20! 154 10- 5- 0- 0 0 A f a Pilifffiffeelial efirAr 0 98 Paved parking & roofs Subcatchment EX-S: Existing Subcatchment Subcatchment EX -S: Existing Subcatchment Hydrograph Type 11 24-hr 1 a0 -YR Rainfall= 5.90" Page 2 Tied Microcom • uter S stems 1/10/2005 �•- ........,--- .- ._....- ..- ..� - -�� .- ..;...... ....._ - �a..L��� Ate* IowLen e R.0 rio ffAr f i n f a1 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WAL 14918 EXI STI N G Type 1124 -hr 100-YR Rainfall =5.99" Prepared by Brady Busse!man MFRA Page 3 H droCAD® 7.00 s/n 000887 © 1 986 -2003 A. •lied Microcom ■ uter S stems 1/10/2005 Inflow Area = 19.370 ac, Inflow Depth = 3.90" for 100 -YR event Inflow = 110.11 cfs a@ 12.02 hrs, Volume= 6.288 of Outflow = 5.50 cfs a@ 13.42 hrs, Volume= 6.188 af, Atten= 95 %, Lag= 83.5 min Primary = 5.50 cfs a@ 13.42 hrs, Volume= 6.188 of Routing by Stor-ind method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Starting Elev= 933.30' Surf.Area= 0.738 ac Storage= 1.401 af Peak Elev= 937.09' a@ 13.42 hrs Surf.Area= 1.186 ac Storage= 5.060 af (3.659 af above start) Plug -Flow detention time= 583.7 min calculated for 4186 af (76% of inflow) Center -of -Mass det. time= 377.4 min ( 1,188.6 - 811.2 ) # Invert Avail.Stora•e Storage Descri tion 933.00 934.00 935.00 936.00 937.00 938.00 939.00 940.00 931.00' 931.00 0.480 932.00 0.583 0.696 0.836 0.944 1.058 1.175 1.295 1.416 1.543 Pond EX P: Existing Pond 9.015 af Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store feet acres acre - feet acre - feet 0.000 0.532 0.640 0.766 0.890 1.001 1.117 1.235 1.356 1.480 0.000 0.532 1.171 1.937 2.827 3.828 4.944 6.179 7.535 9.015 # Routing Invert Outlet Devices 1 Primary 933.30' 12.0" x 87.0' long Culvert RCP, end - section conforming to fill, Ke= 0.500 Outlet Invert= 932.87' S= 0.0049 '1' n= 0.013 Cc= 0.900 Primary OutFlow Max =5.50 cfs @ 13.42 hrs HW= 937.09' (Free Discharge) L1= Culvert (Barrel Controls 5.50 cfs @ 7.0 fps) WAL149I8- EXISTING Prepared by Brady Busselman - MFRA H droCAD® 7.00 s/n 000887 © 1 986 -2003 A. ■ Iied Microcom 12 115- 110- 105- 100 95- 90-: 85- 80. 75, • 7o- u 65 • 60-i• • 50- 45w 40- 35-: 30 -=� 251 2°-' 10- 0 • 11O 1t cfs Pond EX -Pp Existing Pond Hydrograph • • uter S stems Type 11 24 100 Rainfall =5.94" Page 4 1/1 0/2005 rea- maw "„0 ' ' ' ' 0# ' ' rAfA : 004 fOterittePc#407.4 eirxr eeleiZepMeariMelW " . .4" Zereffarfrire/;,,. /4 -171 :2VWffg'rZA;2rdrcedffffl,AifAfear 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) rt 1 0 Inflow 0 Primary FIGURE D ct uct w z cc 0 z z 0 a, H!dON 3nN3A V XVAON FIGURE E Drainage Diagram for WAL14918 Prepared by Brady Busse !man - MFRA 1/11/2005 HydroCAD® 7.00 s/n 000887 0 1986-2003 Applied Microcomputer Systems WAL' 4918 Type 11 24-hr 1.5 -year Ralnfa11 =2.50" Prepared by Brady Busselrnan - MFRA Page 2 H droCAD® 7.00 sin 000887 © 1986 As +plied Microcom. uter S stems 1/11/2005 Time span =0.00 - 48.00 hrs, dt =0.01 hrs, 4801 points Runoff by SCS TR -20 method, U H =SCS Reach routing by Sim -Route method - Pond routing by Sim -Route method Subcatchment 'IS: North Area /Norrell Avenue Runoff Area=13.650 ac Runoff Depth =1.45" Flow Length =1,000' Tc =21.2 min CN =89 Runoff =21.39 cfs 1.655 of Subcatchment 2S: Central Subcatchment 3S: South Pond 2P: Central Pond 3P: South Runoff Area =2.450 ac Runoff Depth =1.31" Tc =10.0 min CN =87 Runoff =4.95 cfs 0.268 of Runoff Area =8.840 ac Runoff Depth =1.87" Tc =15.0 min CN =94 Runoff=20.72 cfs 1.377 of Peak Elev =937.00' Storage = 0.268 af Inflow =4.95 cfs 0.268 af Outflow =0.00 cfs 0.000 af Peak Eiev= 940.45' Storage=1.377 af Inflow= 20.72 cfs 1.377 af outflow =0.00 cfs 0.000 af Pond Eft -P -A: Existing Pond - Modified Out! Peak Elev =933.63' Storage =1.655 af Inflow= 21.39 cfs 1.655 af Outflow =0.00 cfs 0.000 af Total Runoff Area = 24.940 ac Runoff Volume = 3.300 af Average Runoff Depth =1.59" WALI4918 Prepared by Brady Busselman MFRA H droCAD® 7.00 s/n 000887 © 1 986 -2003 A. • lied Microcom Subcatchment - IS: North Area/Norrell Avenue Runoff = 21.39 cfs a@ 12.13 hrs, Volume= 1.655 af, Depth= 1.45" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 1.5 -year Rainfall =2.50" Area ac CN Description 10.190 98 Paved parking & roofs 3.460 61 >75% Grass cover, Good, HSG B Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 21.2 1,000 0.0120 0.8 23-- 22- 21. 20- 19- 18- 17-E 16- 15 N 14-E 13-7 12 -: 10, 8: 7� � 4-- 3� 2- 1 13.650 89 Weighted Average 0 ,;70 10 ,. , L _..:... 10 leo 1 ..,..... 00 0, : to . : : 0,4 00 ....... . 4 / 4 0 0 . . . fr L . /Fig edz teo "A r A 0 ri", ( . . ' ' . . . . 7 . 7 . ' "F. . . 4‘For. - ~et g reaeorei rd fdtrr' Subcatchment 15: North Area /Norrell Avenue 21,39 cfs Hydrograph Lag1CN Method, Norrell Avenue Type 11 24 1.5 - year Rainfa1I =2.54" Page 3 uter S stems 1/11/2005 e 1124 hr 1 RainfaII2 50" u noff Area Hoff VoIume = Hoff Dept =• Lengthl • 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WALT 4918 Type 1124 -hr 1.5 -year Rainfall =2.50" Prepared by Brady Busselman - MFRA Page 4 H droCAD® 7.06 sin 000887 ©1 986 -2003 A•' lied Microcom • uter S stems 1/11/2005 Subcatchment 2S: Central Runoff -- 4.95 cfs @ 1 2.02 hrs, Volume= 0.268 af, Depth= 1.31" Runoff by SCS TR -20 method, UH =SCS, Time Spam 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 1.5 -year RainfaII= 2.50 " Area ac CN Description 1.730 0.720 2.450 Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 87 Weighted Average [ 4.95 cis I Subcatchment 2S: Central Hydrograph Direct Entry, From Storm Sewer Spreadsheet . : : : : : : • in I • Type 1124-hr 1.5 -year Ra infaII 2 50" Runoff Area=2 450 ac Runoff VokimeO 268 of Runoff Depthl 31" Tc10 0 min fifrz, 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WAL14918 Type 11 24-hr 1.5 -year Rainfall= 2.50" by Prepared b Brady usselman - MFRA Page 5 � v H droCAD® 7.00 sin 000887 © 1986-2003 As . lied Microcom • uter S stems 1/11/2005 Subcatchment 35: South Runoff = 20.72 cfs a 1 2.07 hrs, Volume= 1.377 af, Depth= 1.87" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 1.5 -year Rainfall =2.50" Area (ac) CN 7.990 98 0.850 61 8.840 94 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft /ft ft /sec cfs 15.0 23: 22-: 21 20-w 191 18 171 16 157 14 1 13 12 g 11 F. 10.77 7- $7:4 Description Paved parking & roofs >75% Grass cover, Good, HSG B • • 20 72'cfs' Subcatchment 3S: South Hydrograph Direct Entry, From Storm Sewer Spreadsheet • ell 24 -hr 1 ear Ra infaII2 . f Ar a=8 840 noff .377 af noff D I 87" min - 9 e' 3 2- Ad 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) D Runoff WAL14918 Prepared by Brady Bussetman m MFRA H droCAD® 7.00 sin 000887 © 1986 -2003 A. •lied Microcom inflow Area Inflow �- Outflow Primary = Routing by Sim -Route method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Peak Elev= 937.00' © 24.57 hrs SurF.Area= 0.081 ac Storage= 0.268 af Plug -Flow detention time (not calculated) Center -of -Mass det. time (not calculated) # invert Avai i. Stora • e Stora ■ e Descri tion 1 933.00' Elevation Surf.Area (feet) (acres) 933.00 0.024 939.00 0.110 940.00 0.243 943.00 0.360 # Routin Primary 30.0" x 146.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 934.04' S= 0.0100 '1' n= 0.013 Cc= 0.900 939.40' 4.0' long x 0.5' breadth Broad . Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max =0.00 cfs 0.00 hrs HW =933.00' TW =931.00' (Dynamic Tailwater) --W-1 =Culvert ( Controls 0.00 cfs) -2 =Broad ..Crested Rectangular Weir ( Controls 0.00 cfs) 2 Device 1 11.290 ac, Inflow Depth = 0.28" 4.95 cfs a@ 12.02 hrs, Volume= 0.00 cfs a 0.00 hrs, Volume= 0.00 cfs a 0.00 hrs, Volume= Invert Outlet Devices 935.50' Pond 2P: Central I nc. Store Cum. Store acre - feet j 0.000 0.000 0.402 0.402 0.177 0.579 0.905 1.483 uter S stems 1.483 af Custom Stage Data (Prismatic Type 11 24 1.5 - year Rainfall =2.50" Page 6 1/11/2005 for 1.5 -year event 0.268 af 0.000 af, Atten= 100 %, Lag= 0.0 min 0.000 af Listed below WAL' 4918 Prepared by Brady Busselman W INFRA H droCAD® 7.00 stn 000887 © 1986-2003 As died Microcom Pond 2P: Central Hydrograph uter S stems Type 11 24 1.5 - year Rainfall =2.50" Page 7 1/11/2005 Mare#M Fzzeze._,._/ / zroarez.vozeof BreirAW4Mireffiraffrjar, MarjraitV t dff • i - 3_7_Y 1 5 i S# f I i i} S f i s; 5 1 a x 5> >•.. .• t.. • 1 E •• f ••• 3 3 1 i_ - L - -- t - 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Inflow 0 Primary WAL14918 Prepared by Brady Busselman - MFRA HydroCAD® 7.00 sin 000887 © 1986 -2003 Applied Microcomputer Systems Inflow Area Inflow Outflow Primary -- Routing by Sim -Route method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Peak Elev= 940.45' @ 24.84 hrs Surf.Area= 0.316 ac Storage= 1.377 af Plug -Flow detention time (not calculated) Center -of -Mass det. time (not calculated) ## Invert Avail .Stara• e Stora• e Descri • tion 1 Elevation feet 933.00 939.00 940.00 946.00 933.00' # Routin 1 Primary 2 Device 1 8.840 ac, Inflow Depth = 1.87" 20.72 cfs a@ 12.07 hrs, Volume= 0.00 cfs 0.00 hrs, Volume= 0.00 cfs 0.00 hrs, Volume= Surf.Area acres 0.080 0.230 0.301 0.503 3.608 af Custom Stage Data (Prismatic) Listed below Inc. Store acre -feet 0.000 0.930 0.266 2.412 Pond 3P: South Cum.Store acre -feet 0.000 0.930 1.195 3.608 Type 11 24 1.5 year RafnfaII=2.50" Page 8 111 1/2005 for 1.5 -year event 1.377 af 0.000 af, Atten= 100 %, Lag= 0.0 min 0.000 af Invert Outlet Devices ............... . .... ............................... 940.73' 30.0" x '133.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 939.40' S= 0.0100 '1' n= 0.013 Cc= 0.900 941.20' 4.0' long x 0.5' breadth Broad - Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max =0.00 cfs 0.00 hrs HW 933.00' TW=933.00' (Dynamic Tailwater) -'l =Culvert ( Controls 0.00 cfs) ---2 =Broad - Crested Rectangular Weir ( Controls 0.00 cfs) WAL14918 Prepared by Brady Busseman m MFRA H droCAD® 7.00 s/n 000887 © 1 986 -2003 A. •lied Microcom 23 22-E 21- 29 19� 18: 17 16 154 14, j 13- `�' 12-: 0 11 �. uw 16w.. 9. Pond 3P: South Hydrograph uter S stems Type 11 24-hr 1.5-year Rainfall =2.54" Page 9 1/11/2005 of IMP/Argill1111111mova•...- -02M3MYMSffefeff'dff ° ad; Miff r‘Affilief. drogeiMe. ‘ Mr,/ 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WALL 49'18 Prepared by Brady Busse!man - MFRA H droCAD® 7.00 sin 000887 © 1986-2003 A 11 Inflow Area = 24.940 ac, Inflow Depth = 0.80" for 1.5 -year event Inflow = 21.39 cfs a@ 12.13 hrs, Volume= 1.655 of Outflow = 0.00 cfs a@ 0.00 hrs, Volume= 0.000 af, Atten= 100 %, Lag= 0.0 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Sim -Route method, Time Span- 0.00-48.00 hrs, dt= 0.01 hrs Peak EIev= 933.63' a@ 25.21 hrs Surf.Area= 0.784 ac Storage= 1.655 af Plug -Flow detention time (not calculated) Center -of -Mass det. time (not calculated) # Invert Avail.Stora• a Stara • a Descri•tion 931.00' 9.015 af Custom Stage Data (Prismatic) Listed below Type 11 24-hr 1.5 -year Rainfall= 2.50" Page 10 Tied Microcom• uter S stems 1/1 1/2005 Pond EX -P -A: Existing Pond. Modified Outlet Elevation Surf.Area Inc.Store Cum.Store j 1 931.00 0.480 0.000 0.000 932.00 0.583 0.532 0.532 933.00 0.696 0.640 1.171 934.00 0.836 0.766 1.937 935.00 0.944 0.890 2.827 936.00 1.058 1.001 3.828 937.00 1.175 1.117 4.944 938.00 1.295 1.235 6.179 939.00 1.416 1.356 7.535 940.00 1.543 1.480 9.015 # Routi n * Invert Outlet Devices 1 Primary 933.65' 8.0" Vert. Orifice/Grate C= 0.600 Primary OutFlow Max=0.00 cfs a( 0.00 hrs HW 931.00' (Free Discharge) 1 =Orifice /Crate ( Controls 0.00 cfs) WAL14918 Prepared by Brady Busselman - MFRA H droCAD® 7.00 sin 000887 © 1986 -2003 As 'lied Microcom 0 2 4 23 22 21 20 19 18 17 16 15 14 N i 13 12 v 11 10 9 8 7 6 uter S stems Pond ESC -P -A: Existing Pond - Modified Outlet Hydrograph Type 11 24-hr 1.5 -year Rainfall =2.50" Page 11 1/11/2005 PF 0 0 00 3 04, _ , ,, .0 c 2 4rOreard riffer,/f /tin f ' 1 i a / i 1 1 i a i 4° sIaimi,Z•nni.."' 'il 717,A villf' ELooc 0� W [ r E •• a 3 ••• 3 • f i i -- i t - - r . • . 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) B Inflow 0 Primary WALI49I8 Type 1124 -hr 10-year Rarnfall =4.15" Prepared by Brady Busselman - MFRA Page 1 H droCAD® 7.00 s/n 000887 © 1 986 - 2003 Milled Microcom. uter S stems 1/11/2005 Time span =0.00 -48.00 hrs, dt =0.01 hrs, 4801 points Runoff by SCS TR -20 method, UH =SCS Reach routing by Sim -Route method - Pond routing by Sim -Route method Subcatchment 'IS: North ArealNorrell Avenue Runoff Area=1 3.650 ac Runoff Depth= 2.96" Flow Length =1 ,000' Tc =21.2 min CN=89 Runoff =42.97 cfs 3.372 of Subcatchment 2S: Central Subcatchment 3S: South Pond 2P: Central Pond 3P: South Runoff Area =2.450 ac Runoff Depth= 2.77" Tc=10.0 min CN =87 Runoff =10.25 cfs 0.566 of Runoff Area=8.840 ac Runoff Depth= 3.47" Tc =15.0 min CN =94 Runoff =37.21 cfs 2.557 of Peak Elev =938.65' Storage =0.379 af Inflow =28.35 cfs 3.123 af Outflow=28.18 cfs 3.123 af Peak Elev =94l .95' Storage =1.981 af Inflow =3721 cfs 2.557 of outflow= 24.49 cfs 2.557 af Pond EX - Existing Pond - Modified Out' Peak Elev= 937,72' Storage =5.835 af Inflow =70.88 cfs 6.495 af Outflow=3.25 cfs 6.280 af Total Runoff Area = 24.940 ac Runoff Volume = 6.495 af Average Runoff Depth = 3.13' WALL 49I 8 Type 11 24-hr 10-year Rainfal1=4.15" Y Brady Prepared Brad Busseiman - MFRA Page 2 p H droCAD® 7.00 s/n 000887 © 1986 -2003 As' lied Microcom ■ uter S stems 1/11/2005 Subcatchment 'IS: North Area /Norrell Avenue Runoff -- 42.97 cfs @ 12.13 hrs, Volume= 3.372 af, Depth= 2.96" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 10 -year Rainfall =4.15" Area ac CN Description 10.190 3.460 13.650 21.2 48 46- 44-: 42° 40 38-- 38- 34 32: 30 • 28- U 26u 24- O 22 LL 20 1 8m 16 14- 12~: 10 8- 4- 2 0 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 89 Weighted Average Tc Length Slope Velocity Capacity Description min feet ftift ft/sec cfs 1,000 0.0120 0.8 Subcatchment IS: North Area /Norrell Avenue Hyclrograph 0 0, 97 Cf$ u noff Volume- , unoff De pth .... - low Length Lag /CN Method, Norrell Avenue { ainfa Hoff rea=13.650 ac VV ..d .. ... �.. �,.,........ �!.,,�....�...,,�...,.......... 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WAL14918 Type 11 24-hr 10 -year Rainfa11= 4.75" Prepared by Brady Busselman - MFRA Page 3 H droCAD® 7.00 sin 000887 © 1 986 - 2003 A* *lied M iicrocom • uter S stems 1/11/2005 Runoff -- 10.25 cfs a@ 12.01 hrs, Volume= 0.566 af, Depth= 2.77" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type H 24 -hr 10 -year Rainfall =4.15" Area ac CN Description 1.730 0.720 61 >75% Grass cover, Good, HSG B 2.450 87 Weighted Average 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 6- 47 3- 2 • O25cs< Subcatchment 25: Central Subcatchment 2S: Central Ar lezeizze Hydrograph k ' Direct Entry, From Storm Sewer Spreadsheet - ear ype i R i u noff Area2 450 ae t u noff: V01 u me o. $66 a Runoff (Depth 2 "7l" Tc10 0 n11 n i . N= 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Runoff WALT 4913 Type 11 24-hr 10 -year Rainfa11 =4.15" Prepared by Brady Busselman - MFRA Page 4 H droCAD® 7.00 sin 000887 © 1 986 -2003 A. •lied Microcom • uter S stems 1/11/2005 Runoff -- 37.21 cfs @ 12.06 hrs, Volume= 2.557 af, Depth= 3.47" Runoff by SCS TR -20 method, UH =SCS, Time Span = 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 10 -year Rainfall= 4.15" Area ac CN Description 98 Paved parking & roofs 0.850 61 >75% Grass cover, Good, HSG B 8.840 94 Weighted Average 7.990 Tc Length Slope Velocity Capacity Description min feet ft/ft ft /sec cfs ........................... 15.0 40 38 36 34 32 30 28 26 N 24` 8. 22 v 2C u 18 1E 14 12 10 8 4 2- �• Rte`" "fre "NEWOffed lOYZorMreeZeire efeeZber G 1 /4M20 0 2 4 Subcatchment 3S: South Hydrograph Direct Entry, From Storm Sewer Spreadsheet Subcatchment 3S: South r e t s • [ s . . . s F : r . s i r . . . . . . Z . . . - ; • - ` • - i - - - - [ t . 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Runoff WAL1491B Prepared by Brady Busselman - MFRA H droCAD® 7.00 stn 000887 © 1 986 -2003 A. 'lied Microcom Inflow Area Inflow -- outflow Primary -- Routing by Sim -Route method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Starting Elev- 937.00' Surf.Area= 0.081 ac Storage= 0.268 af Peak Elev= 938.65' @ 12.16 hrs Surf.Area= 0.105 ac Storage= 0.379 af (0.111 af above start) Plug -Flow detention time= 84.8 min calculated for 2.855 af (91 % of inflow) Center-of-Mass det. time 10.2 min ( 832.3 - 822.1 ) # Invert Avail.Stora• a Stora• a Descri•tion Surf.Area lnc.Store Cum.Store acres acre - feet ) (ac fet 0.024 0.000 0.000 0.110 0.402 0.402 0.243 0.177 0.579 0.360 0.905 1.483 Elevation feet 933.00 939.00 940.00 943.00 933.00' # Routin 1 Primary 2 Device 1 11.290 ac, Inflow Depth = 3.32" 28.35 cfs a@ 12.13 hrs, Volume= 28.18 cfs a@ 12.16 hrs, Volume= 28.18 cfs a© 12.16 hrs, Volume= Invert Outlet Devices 935.50' Pond 2P: Central uter S stems 1.483 af Custom Stage Data (Prismatic) Listed below Type 11 24 1O -year Rainfall =4.15" Page 5 1/11/2005 for 10 -year event 3.123 af 3.123 af, Atten= 1%, Lag= 2.1 min 3.123 af 30.0" x 146.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 934.04' 8= 0.0100 '1' n= 0.013 Cc= 0.900 937.00' 4.0' long x 0.5' breadth Broad - Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max =28.17 cfs a 12.16 hrs HW =938.65' TW 935.83' (Dynamic Tailwater) t-_-1 =Culvert (Passes 28.17 cfs of 32.59 cfs potential flow) t-2 =Broad - Crested Rectangular Weir (Weir Controls 28.17 cfs a@ 4.3 fps) WAL14918 Prepared by Brady Busselman MFRA H droCAD® 7.00 sin 000887 © 1986-2003 A. ■lied Microcom 28:" 26= �. 24:" 22-1 20-: 18 � 16_ 14 -: ` " 12=:° 0,14 000 S r dr,xeisfecwev 0 ze moo" 09%4 28.35 cfs 10 12 14 16 Pond 2P: Central Hydrograph uter S stems a Type 1124 -hr 1O -year Rainfall 4.15" Page 6 1/11/2005 mivrofomm r4d#r-do tez e ro ow Area Jev= rage = 0.379 -af 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WAL14918 Prepared by Brady Busselman - MFRA H droCAD© 7.00 sin 000887 ©1 986 -2003 A* *lied Microcom Inflow Area = inflow = Outflow - Primary 8.840 ac, Inflow Depth = 3.47" 37.21 cfs @ 12.06 hrs, Volume= 24.49 cfs a@ 12.19 hrs, Volume= 24.49 cfs a@ 12.19 hrs, Volume= Pond 3P: South uter S stems # Invert Avail.Stora■e Storage Descri•tion 1 933.00' 3.608 af Custom Stage Data (Prismatic Type 11 24 10-year Rainfall =4.15" Page 7 1/11/2005 for 10 -year event 2.557 af 2.557 af, Atten= 34 %, Lag= 7.4 min 2.557 af Routing by Sim -Route method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Starting Elev= 940.45' Surf.Area= 0.316 ac Storage= 1.376 af Peak Elev= 941.95' @ 12.19 hrs Surf.Area= 0.367 ac Storage= 1.981 af (0.605 af above start) Plug -Flow detention time 308.5 min calculated for 1.180 af (46% of inflow) Center -of -Mass det. time= 41.1 min ( 825.0 - 783.9 ) Elevation Surf.Area lnc.Store Cum.Store __(teetl___iacrL__(acre-_L_(a cre�feet 933.00 0.080 0.000 0.000 939.00 0.230 0.930 0.930 940.00 0.301 0.266 1.195 946.00 0.503 2.412 3.608 # Routin 1 Primary Listed below 2 Device 1 Invert Outlet Devices 938.33' 30.0" x 133.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.00' S= 0.0100 '1' n= 0.013 Cc= 0.900 940.45' 4.0' long x 0.5' breadth Broad- Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max =24.48 cfs a@ 12.19 hrs Hw= 941.95' Tw= 938.65' (Dynamic Tailwater) 1= culvert (Passes 24.48 cfs of 36.41 cfs potential flow) - 2=Droad- crested Rectangular weir (Weir Controls 24.48 cfs © 4.1 fps) WALT 4918 Prepared by Brady Busselman w MFRA HydroCAD® 7.00 s/n 000887 © 1985 -2003 Applied Microcomputer Systems 40 38 36 34 32 30 28 26 24 22 0 20 ua 18 16 14 12 10 8 6 4 2 0 104 j � 4. j mere 4e# 1 0 ram a re 041PoreiwierzeAmm,timmeritew A femme woo deemeo yds rezmrazo re#2 orzeffzeozs remyzzee2g rzze — -5 • t•ra NEM iE. 0 2 4 8 i' 10 12 14 16 18 Pond 3P: South Hydrograph 20 22 24 26 Time (hours) E e : 28 30 32 34 36 Type 11 24-hr 1O -year Rainfal1=4.15" Page 8 1/1 1/2005 38 40 42 44 46 48 8 inflow 0 Primary WALI4918 Type 11 24-hr 10-year Rainfall =4.15" Prepared by Brady Busselman - MFRA Page 9 H droCAD® 7.00 sin 000887 © 1986-2003 A. *lied Microcom. uter S stems 1/11/2005 Pond EX -P-A: Existing Pond - Modified Outlet Inflow Area = 24.940 ac, inflow Depth = 3.13" for 10 -year event Inflow = 70.88 cfs a@ 12.14 hrs, Volume= 6.495 of Outflow = 3.25 cfs a@ 15.13 hrs, Volume= 6.280 af, Atten= 95 %, Lag= 179.8 min Primary = 3.25 cfs a@ 15.13 hrs, Volume= 6.280 of Routing by Sim -Route method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Starting Elev= 933.65' Surf.Area= 0.787 ac Storage= 1.669 af Peak Elev= 937.72' ( 15.13 hrs Surf.Area= 1262 ac Storage= 5.835 af (4.166 af above start) Plug -Flow detention time 987.1 min calculated for 4.610 of (71% of inflow) Center -of -Mass det. time 664.0 min ( 1,485.8 - 821.8 ) # Invert Avail . Stora• e Stara ■ e Descri tion 931.00' 9.015 af Custom Stage Data (Prismatic) Listed below Elevation Su rf.Area I nc. Store cum. Store feet acres acre -feet acre -feet 931.00 0A80 0.000 0.000 932.00 0.583 0.532 0.532 933.00 0.696 0.640 1.171 934.00 0.836 0.766 1.937 935.00 0.944 0.890 2.827 936.00 1.058 1.001 3.828 937.00 1.175 1.117 4.944 938.00 1.295 1.235 6.179 939.00 1.416 1.356 7.535 940.00 1.543 1.480 9.015 # Routin . Invert Outlet Devices .................................................. ............................... 1 Primary 933.65' 8.0" Vert. Orifice /Grate C= 0.600 Primary OutFlow Max =3.25 cfs @ 15.13 hrs HW= 937.72' (Free Discharge) t°°1= Orifice /Grate (Orifice Controls 3.25 cfs @ 9.3 fps) WAL14918 Prepared by Brady Busselman MFRA H droCAD® 7.00 s/n 000887 © 1988 -2003 As stied Microcom 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 Pond EX -P -A: Existing Pond - Modified Outlet Hydrograph I ds: 00 04 / 4 , vff r , • s s s e s 1" • j . •s 0 2 4 fi 8 10 12 14 16 18 20 22 24 26 Time (hours) uter s stems 28 30 32 34 36 38 40 42 Type 11 24 -hr 1O -year Rainfall= 4.15" Page 10 1/11/2005 44 46 48 0 Inflow 0 Primary WALT4918 Prepared by Brady Busselman - MFRA H droCAD® 7.00 sin 000887 © 1986 -2003 A Subcatchment 25: Central Subcatchment 3S: South Pond 2P: Central Pond 3P: South Type 11 24 100 - year Rainfall =5.90" Page 1 lied Microcom * uter S stems 1/11/2005 1• Time span= 0.00 -48.00 hrs, dt =0.01 hrs, 4801 points Runoff by SCS TR -20 method, UH =SCS Reach routing by Sim -Route method - Pond routing by Sim -Route method Subcatchment 18: North Area /Norrell Avenue Runoff Area =1 3.650 ac Runoff Depth = 4.64" Flow Length =1,000' Tc =21.2 min CN=89 Runoff= 65.98 cfs 5.276 of Runoff Area =2.450 ac Runoff Depth =4.42" Tc =10.0 min CN =87 Runoff =15.96 cfs 0.903 of Runoff Area= 8.840 ac Runoff Depth =5.20" Tc =15.0 min CN =94 Runoff =54.45 cfs 3.829 of Peak Elev= 939.75' Storage =0.534 af Inflow =44.70 cfs 4.731 af outflow= 37.81 cfs 4.731 af Peak Elev= 942.47' Storage= 2.189 af Inflow =54.45 cfs 3.829 af Outflow =38.13 cfs 3.828 af Pond EX -P -A: Existing Pond - Modified 0 Peak Eiev =939.48' Storage= 8.252 af inflow =103.79 cfs 10.008 af Outflow=3.94 cfs 9.279 af Total Runoff Area = 24.940 ac Runoff Volume =10.008 0.008 of Average Runoff Depth = 4.82'° WAL14918 Type 11 24-hr 100 -year Rainfa11 -5.90" Prepared by Brady Busselman m MFRA Page 2 H droCAD® 7.00 s/n 000887 © 1 986 -2003 A w ■lied [Ili icrocom uter S stems 1/11/2005 Subcatchment '1S: North Area /Norrell Avenue Runoff -- 65.98 cfs a@ 12.13 hrs, Volume= 5.276 af, Depth= 4,64" Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 100 -year Rainfall -5.90" Area ac CN Descri■tion 10.190 3.460 61 >75% Grass cover, Good, HSG B 13.650 89 Weighted Average 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description min feet ft/ft ftlsec cfs 21.2 1,000 0.0120 0.8 70- 65 60 55 50 45 t3 ^ 40 g 35 30 25 20 15 Subcatchment 15: North Area /Norrell Avenue Hydrograph Los Runoff Areal 365Q ac plume= Hoff e Il 24hr 1OOyear infa11= 5:90 ' unoff'Depth Lengt Tc= 76 of 4.64 ". "..... 0ovu min .. 00 00 10 a ir,* 5 0 2 4 6 10 12 14 16 18 20 22 24 26 Time (hours) Lag/CN Method, Norrell Avenue 28 30 32 34 36 38 40 42 44 46 48 WALI49118 Type 11 24-hr 100 -year Rainfall=5. 90" Prepared by Brady Busselman - MFRA Page 3 H droCAD® 7.00 s/n000887 ©1 986 -2003 A• 'lied Microcom • uter S stems 1/11/2005 17- 16µ 157: 14- 13 12w 5= 4: 3 -y 2„ 0- 0 2 4 6 8 10 12 14 16 Subcatchment 2S: Central Runoff -- 15.96 cfs a 12.01 hrs, Volume= 0.903 af, Depth= 4.42" Runoff by SCS TR -20 method, UH=SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 100 -year Rainfall =5.90" Area ac ON Descri tion 1.730 98 Paved parking & roofs 0.720 61 >75% Grass cover, Good, HSG B 2.450 87 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 Subcatchment 2S: Central Hydrograph t r. s Afirawore e II' 24 -hr -100 -year ain Runoff Area2 450 ac inoff Vo IumeO 903 o unoff Depth4 42" I -n 18 { Direct Entry, From Storm Sewer Spreadsheet 20 22 24 26 28 30 32 34 36 38 40 Time (hours) 42 44 46 48 0 Runoff WALT 49 3 Type II 24 -hr 100-year Rainfall =5.90'► Prepared by Brady Busse!man a MFRA Page 4 H droCAD® 7.00 sin 000887 © 1986 -2003 As *Tied Microcom • uter S stems 1/11/2005 Runoff 54.45 cfs @ 12.06 hrs, Volume= Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Type 11 24 -hr 100 -year Rainfall =5.90" Area ac CN Descri.tion 7.990 0.850 8.840 Tc Length Slope Velocity Capacity Description min) (feet) (ft /ft) (ft /sec) (cfs) 15.0 60- 55- 50- 45- N 35- 8 30 - 25 Subcatchment 3S: South 98 Paved parking & roofs 61 >75% Grass cover, Good, HSG B 94 Weighted Average Hydrograph 3.829 af, Depth= 5.20" Direct Entry, From Storm Sewer Spreadsheet Subcatchment 3S: South 54:45 cfs • Typ e1124hriOO-year R ainfa115 9Ov Hoff Area=8 840 ac Runoff VoIume3 829 af Runoff Depth=5 20" Tc15 0 min N =94 40- l 100 20- 15- 10 .41VA000 xgraMilakastima - IMISIDYZAti cl 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Runoff WAL14918 Prepared by Brady Busse!man m MFRA HydroCAD® 7.00 s/n 000887 © 1986 -2003 Applied Microcomputer Systems [86] Warning: Oscillations may require smaller dt Inflow Area = Inflow Outflow Primary = 11.290 ac, Inflow Depth = 5.03" 44.70 cfs a@ 12.12 hrs, Volume= 37.81 cfs @ 12.13 hrs, Volume= 37.81 cfs 12.13 hrs, Volume= Pond 2P: Central Type 11 24-hr 100-year Rainfall =5.90" Page 5 1/1 1/2005 for 100-year event 4.731 af 4.731 af, Atten= 15 %, Lag= 0.6 min 4.731 af Routing by Sim -Route method, Time Span= 0.00 -48.00 hrs, dt= 0.01 hrs Starting Elev= 937.00' Surf.Area= 0.081 ac Storage= 0.268 af Peak Elev= 939.75' a@ 12.33 hrs Surf.Area = 0.209 ac Storage= 0.534 af (0.266 af above start) Plug -Flow detention time 95.6 min calculated for 4.463 af (94% of inflow) Center -of -Mass det. time 37.3 min ( 844.5 - 807.1 ) # Invert Avail . Stora• e Stora ■ e Descri 'tion 933.00' # Routin 1 Primary 2 Device 1 1.483 af Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store feet acres acre - feet acre - feet 933.00 0.024 0.000 0.000 939.00 0.110 0.402 0.402 940.00 0.243 0.177 0.579 943.00 0.360 0.905 1.483 Invert Outlet Devices 935.50' 30.0" x 146.0' long Culvert RCP, sq.cut end projecting, ire= 0.500 Outlet Invert= 934.04' S= 0.0100 '1' n= 0.013 Cc= 0.900 937.00' 4.0' long x 0.5' breadth Broad - Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max =37.29 cfs 12.13 hrs HW =939.31' TW= 936.75' (Dynamic Tailwater) t-1= Culvert (Barrel Controls 37.29 cfs © 7.6 fps) -2= Broad - Crested Rectangular Weir (Passes 37.29 cfs of 46.59 cfs potential flow) WAL14918 Prepared by Brady Busselman - MFRA H droCAD® 7.00 stn 000887 © 1986 -2003 A. flied Microcom 50 48 46 44 42 40 38 36 34 32 30 F. 28 26 24 22 20 18 16 14 12 10 8 6 4 2 Pond 2P: Central Hydrograph uter s stems Type 11 24 100 - year Rainfall =5.90" Page 6 1/11/2005 lool 1; _ . 37. cfs'= ..... ; . 00 100 v o ,, 0 0 0 00 1 0 0 0743 v., ..H. :... .:. 0o0 ,A ,. : : ! , : : 000 dA; tp,„ : ; dirmlowvir,„,00 ‘, TrT'FPFeaofrorozregtvMrilie".dre2*W,Xre . , 0 , z, s i>> ,s, s i s£ s r f s s i r F. 1 i s 1 E c i , : . r a ; • ., //F ; s > s s s Z x R x > > 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 0 Inflow 0 Primary WAL14918 3 Prepared by Brady Busselman - MFRA H droCAD® 7.00 s/n 000887 © 1 986 -2003 A. 'lied Microcom Inflow Area = Inflow = Outflow Primary 8.840 ac, inflow Depth = 5.20" 54.45 cfs a@ 12.06 hrs, Volume= 38.13 cfs a] 12.17 hrs, Volume= 38.13 cfs a@ 12.17 hrs, Volume= Pond 3P: South Routing by Sim -Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Starting Elev= 940.45' Surf.Area= 0.316 ac Storage= 1.376 af Peak Elev= 942.47' aJ 12.17 hrs Surf.Area= 0.384 ac Storage= 2.189 af (0.812 af above start) Plug -Flow detention time= 223.7 min calculated for 2.452 af (64% of inflow) Center -of -Mass det. time 36.1 min ( 809.8 - 773.7 ) # Invert Avai i. Stora• e Stora . e Descri•tion Elevation feet 933.00 939.00 940.00 946.00 933.00' Surf.Area acres 0.080 0.230 0.301 0.503 3.608 af Custom Stage Data (Prismatic Inc.Store acre -feet 0.000 0.930 0.266 2.412 Cum.Store acre -feet 0.000 0.930 1.195 3.608 uter S stems Type 11 24 100 - year Rainfall=5.90" Page 7 1111/2005 for 100 -year event 3.829 af 3.828 af, Atten= 30 %, Lag= 6.8 min 3.828 af Listed below Invert Outlet Devices 938.33' 30.0" x 133.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.00' S= 0.0100 '/' n= 0.013 Cc= 0.900 940.45' 4.0' long x 0.5' breadth Broad - Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max =38.12 cfs a@ 12.17 hrs HW =942.47' TW =939.46' (Dynamic Tailwater) -1 =culvert (Passes 38.12 cfs of 40.18 cfs potential flow) '-2 =Broad ..Crested Rectangular Weir (Weir Controls 38.12 cfs © 4.7 fps) # Routin 1 Primary 2 Device 1 WAL1 491 3 Prepared by Brady Busselman - MFRA H droCAD® 7.00 sin 000887 © 1985 -2003 A ■■ 60 55 50 45 40 N 35 30 0 25 20 15 10 lied Microcom Pond 3P: South Hydrograph uter S stems Type 11 24 100 - year Rainfall= 5.90" Page 8 1/11/2005 5 Fix:4 1 JEW:01 1 2~01,0 Treler 0 �� '6 ��r 3 f - - i 7 } [ � . . F j � - - - } F a 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) WAL14918 Prepared by Brady Busseman - MFRA H d roCAD® 7.00 sin 000887 ©1 986 --2003 A 1• Pond EX -P -A: Existing Pond - Modified Outlet [80] Warning: Exceeded Pond 2P by 0.01' @ 25.02 hrs (2.01 cfs) Inflow Area = 24.940 ac, Inflow Depth = 4.82" for 100 -year event Inflow = 1 03.79 cfs @ 12.13 hrs, Volume= 1 0.008 of Outflow = 3.94 cfs @ 15.85 hrs, Volume= 9.279 af, Atten= 96 %, Lag= 223.1 min Primary = 3.94 cfs a@ 15.85 hrs, Volume= 9.279 of Routing by Sim -Route method, Time Span= 0.00-48.00 hrs, dt= 0.01 hrs Starting Elev= 933.65' Surf.Area= 0.787 ac Storage= 1.669 af Peak Elev= 939.48' a@ 15.85 hrs Surf.Area= 1.478 ac Storage= 8.252 af (6.583 af above start) Plug -Flow detention time 1,055.5 min calculated for 7.610 af (76% of inflow) Center -of -Mass det. time= 777.3 min ( 1,598.1 - 820.8 ) # Invert Avail.Stora•e Storage Descri.tion 931.00' 9.015 af Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store feet acres acre -feet nacre - fee } 931.00 0.480 0.000 0.000 932.00 0.583 0.532 0.532 933.00 0.696 0.640 1 .171 934.00 0.836 0.766 1.937 935.00 0.944 0.890 2.827 936.00 1.058 1.001 3.828 937.00 1.175 1.117 4.944 938.00 1.295 1.235 6.179 939.00 1.416 1.356 7.535 940.00 1.543 1.480 9.015 # Routin ■ Invert outlet Devices 1 Primary 933.65' 8.0" Vert. Orifice/Grate C= 0.600 Type 11 24 100 - year Rainfall =5.94" Page 9 lied Microcom.uter S stems 1/1112005 Primary OutFlow Max= 3.94 cfs a@ 15.85 hrs HW =939.48' (Free Discharge) t.1 =orifice /Grate (orifice Controls 3.94 cfs @ 11.3 fps) WALL4918 Prepared by Brady Busselman v MFRA H droCAD® 7.00 s/n 000887 © 1 986 -2003 A. idled Microcom 115 110 105 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15°. 10 22 24 26 Time (hours) 0 2 4 6 8 10 12 14 16 18 20 uter S stems Pond EX -P -A: Existing Pond - Modified Outlet Hydrograph 28 30 32 34 Type 11 24-hr 100 -year Rainfa11 =5.90" Page 10 1/11/2005 36 38 40 42 44 46 48 0 Inflow 0 Primary FIGURE F - 7 11111111 il lh . r x J 4 .• � $. _40A 4 'ix** , VW* 2111,Kceal Akra RAPIN g tf, amp 1 \ ,, It kirt„ „to 14,1,, FIGURE G FIGURE H