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HomeMy WebLinkAbout2004-06-09 Stormwater Mgmt Plan Updated 07-20-043 :r Scott A. Ward, P.E. �l..R.t.rr.: �y .'t� r d` KS.,;'i d h:; F•�v .,�� s s: - •.s �•.E:� ... ,: j+.L�'". aw •:�:£�, h• __�t ..1ti�w. ;,i: •rr,• i��. v..� , `•� n• ,.Jy ', �kJt,, r'f.•�•.t.r.�•`�. ":' •sr -.•`^ �� 7r'S' �..' • u ..e. „3, re ...��',a;.�.•.r: u......,:.`- .'C.�,..:s.'�,.. �h,a.�.tFa:. - � .... .. - ._..�.. r... _ - ......... ... -... -. ...� n.,......,....._Y - ._.-- .- ...s..,...�;,� :: -��.� � = �'t Y ' .�.-� _ r..,a :v.. a '' �' June 9, 2004 Our File No. 5046 Date .ti • l: R .o- -, � .'S .Y^r..Y:f � "' r .,. gt ,, ' " • rod •: a': st.1 r ..:'� , : � `i.�.a,�Y��.�:..tr!..�. - -... act .__.....c.��'x ..=::::i� -r.J .:_.v:..., ' ,ca�a", '�r. Reg. No. STEVENS ENGINEERS STORMWATER MANAGEMENT PLAN FOX HOLLOW P.U.D. OAK PARK HEIGHTS, MINNESOTA 1656 LIVINGSTONE ROAD HUDSON, WISCONSIN 54016 www.stevensengineers.com (715) 386 -5819 (800) 822 -7670 (651) 436 -2075 FAX: (715) 386 -5879 Y•.. : eFi-•i -r• E+ �r i -•"fit E- .� I hereby certify that this specification was prepared by me REVISIONS: or under my direct supervision and that I am a duly Registered 7-20-04 Updated Figures 4 & 5. P j essional Engineer under the laws of the State of Minnesota. Updated control structure dwg. JUNE 9 2004 40921 _"..•[•? ' „ C .. . c': ^ .'. :. []•, � ..]'' - ]';F,x'• . v ty.5�. �e - <.. .a: :�.'.'`,u -n S. 'fi ,z. i�� r. . a _ ._ :s��'��:� ^�....,...; •z�.. ,HS...yw:."�'Sra; }::w. -x_ a. r!e TABLE OF CONTENTS Page No. Table of Contents.... 1 Introduction 2 Existing Conditions 2 Proposed Conditions 3 Stormwater Drainage Analysis 3 Model 3 Soils 3 Land Use 3 Best Management Practices 4 Results 4 Table I. Summary of Stormwater Modeling Results 4 Table 2. Pond Modeling Results 4 Figure 1. Location Map and Topographic Map of Area 5 Figure 2. Soil Type Map 6 Figure 3. Stormwater Plan 7 Figure 4. Site Grading Plan 8 Appendix A Modeling Results for Existing Conditions A 1 Appendix B Modeling Results for Proposed Conditions A2 Appendix C Supplemental Plans and Details A3 Stormwater Management Plan-- East Oaks P.U.D. Second Addition 1 INTRODUCTION Presented in this report is the stormwater management plan for the proposed Fox Hollow PUD (formally referred as the East Oaks PUD Second Addition) Condominium and Office Building Development in the City of Oak Park Heights, Washington County, Minnesota. This report is presented to the City of Oak Park Heights and the Middle -St. Croix Watershed Management Organization (WMO) for review, comment and approval. The proposed site is located in the eastern part of the City approximately 0.5 miles east of the Intersection of Highway 36 and Osgood Ave on both Street North. The total area of the property is 2.4 acres. The site is currently zoned B2 and R -B . This plan includes the following information: 1. A detailed site topography plan showing existing and proposed features, contours, etc. 2. Calculations showing comparison of pre-development and post-development conditions. Calculations showing post-development peak discharge rates are not increased over pre -- development discharge rates for a 2.4 inch rainfall event and the 10 --year and 100-year storm events. 3. Design details for outlet control structure . This plan, in conjunction with the Grading and Sediment-Erosion Control Plan, satisfies the requirements for a Stormwater Pollution Prevention Plan (SWPPP) required by the Minnesota Pollution Control Agency (MPCA) for the General Stormwater Permit for Construction Activity (M N R100001). These documents shall be kept on file by the Property Owner as required under the General Stormwater Permit. EXISTING CONDITIONS The site is currently undeveloped and consists of open grassland with a few trees scattered through out the site. The ground cover breakdown is as follows: 0.12 acres of paved roads (existing R.O.W.) 2.21 acres of grass cover The terrain consists mainly of gradual slopes (0 -5 %). Some greater slopes (10 to 20 %) exits on the east end of the property. The property currently drains toward the southeast into a low area on the adjacent property. The existing ground water elevation will be confirmed when soil borings are performed for this project this summer. The existing on -site storm water pond serves the area to the south of the property (East Oaks Twin homes). This area is approximately 5.97 acres as shown in Figure 3. This pond will be modified to accommodate the proposed project. Stormwater Management Plan -- East Oaks P. U.D. Second Addition 2 PROPOSED CONDITIONS The proposed site conditions include the development of three buildings, one large office building, one small office building, and a 32 unit condominium building with footprint areas of 4658 square feet (sf), 2065 sf and 13,045 sf respectively. The site development also includes an entrance road, parking lots, retaining walls and a redesigned storm water pond. The proposed site that was evaluated for the site improvements consists of approximately: 0.45 acres of buildings 0.63 acres of pavement 1.25 acres of short grass cover The storm water from the new development will collected, through the use of curb and gutter, by two catch basins located at the east end of the parking lot and one catch basin near the garage entrance to the condominium buildings. The storm water will be directed to an expanded s torm water pond. Figure 4 shows the direction of drainage for the proposed site. The location of the catch basins are not shown on this plan. The existing storm water pond outlet will be increased in size to accommodate the new site conditions. A control structure will also be added to the outlet. See Appendix C for the control outlet detail. The storm water plan is based on a fully developed site including all parking Tots being paved and the construction of all buildings. STORM WATER DRAINAGE ANALYSIS Model The analysis of the site was performed using the I- IydroCAD software. The flows were routed through the existing 36" storm sewer for purposes of computing summed hydrographs to compar e existing and proposed flows. This program basis its runoff calculations on the SCS TR -20 model. The stormwater for the proposed site was modeled and compared to the runoff of the exi sting site for a 2.4 inch rainfall event and storm frequencies 10-year and 100 -years over a 24 -hour period. The raw data generated from this analysis is included in Appendices A and B. The data from this model is summarized in T able 1. The total drainage area evaluated is 8.3 acres. Figure 1 shows the location of the site and the topography and hydraulic features in the area. The proposed conditions were evaluated by dividing the area into two (2) drainage areas as shown in Figure 3. The same areas were used to evaluate both the existing and proposed drainage conditions. Figures 4 shows both the existing and proposed topography for the site. The ground water elevation for the site is not known at this time. Soils The on -site soils are classified in the hydraulic groups B as shown in Figure 2. Some fill has been added to this site over the years so further exploration through soil boring testing will be required. Land Use The site has been inspected and the majority of the existing land use is tall grass cover with scattered oaks and cottonwoods. The curve numbers were determined based on this land use and as defined in the modeling program. Stormwater Management Plan— East Oaks P. U.D. Second Addition 3 Best Management Practices (BMPs) A wet pond detention system meeting the NURP standards with a minimum 3' average pond depth was selected based on recommendations outlined in the Minne sota Urban Small Sites BMP Manual - Stormwater Best Management Practices for Cold Climates by the Metropolitan Council and the high groundwater conditions. This type of BMP will limit the effects downstream by reducing the peak flow rates and energy of the stormwater. Included in the pond system is an outlet structure consisting of a 5' diameter concrete structure with two (2) 15" diameter orifices. A detail of the outlet structure is included in Appendix C. The pond system is designed to provide a stormwater release rate of the post - development site that is less than the pre - development site release rate for a 1 -year (2.5" rainfall event) and 100 -year storm event. Results A summary of results for the stormwater modeling is shown in Tables 1 and 2. As the results of the model show, the pre- and post - development peak discharge rates for Areas 1 and 2 do not change for the 100 year storm event from the existing 36" pipe. The peak discharge rates for Area 1 change dramatically given that the development is taking place in this area. Table 1. Summary of Stormwater Modeling Results (existing conditions /proposed conditions) Storm Event 2.4" event 10 -YEAR 100 -YEAR *Weighted curve number Inflow (cfs) Storage Capacity (cf) Area Designation 1 2 Reach (36 ") 1 2 Reach (36 ") 1 2 Reach (36 ") Peak Discharge Outflow Rate (cfs) Peak Water Elevation (ft) Area (ac) 2.33 5.97 8.30 2.33 5.97 8.30 2.33 5.97 8.30 CND` 70 181 76/76 NA 81 NA 176 70181 76176 2.5" Rainfall 5.42/9.40 2.62/4.75 842,441842.93 2,464/17,487 Runoff (ac -ft) Table 2. Pond Modeling Results (existing conditions /proposed conditions) 0.06910.166 0.281 10.309 0.339 /0.450 NA 10.396 NA 10.825 NA/1.185 0.485/ 0.686 1.514/ 1.514 1.97612.154 10 -YEAR NAl24.51 NA/15.53 NA/844.05 NA/24,295 Peak Discharge Rate (cfs) 1.2014.02 5.4216.08 3.2914.71 NA 19.34 NA1 16.65 NA 1 15.47 9.70/ 15.71 29.70130.10 24.28121.88 100-YEAR 29.70/43.44 16.27/21.92 844.58/845.44 17,596/35,301 Stormwater Management Plan— East Oaks P.U.D. Second Addition 4 s -=• e rav F a J[ \‘'cl V))))‘\ U�r • r.J71 34 ewa 85 0 / 0 statl . t n, yOrs 1 D u l FIGURE 1 C p Rs c. 0=1_1 L, L.6 4 / t , (-AA V-4 - TY p 4 • 155 561 7 FIGURE 2 it 111,1111 � ff 4 101 f l o g drmArAN . A " PEW / , ,,•,,,�� � � TA P A l ❑3 tlp § a -ii .8 d A 1p i pp ;t \ ' � \ i I ❑ i!1 -\ 1 , II ao ao .3 m °' 9� � V L ,n oa ' ■ /7/ 2) ! � 1 � � i � �. ► Allk_M ib : 101Z-Al its �� P ' r - v- 44 a D 07 H in 7 H -4 3 Z a0 3D 0 aD w U cn w CD 3rt N 3113 VIOS3NNI�V . 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RE 1 1 :4\ . gy i i lit E i' i� 1 i; J • . / Diu,~ / �',Rf1, �sss— i 1 / / 17 n 1 L __. 1 / / .. 1 o i h , 41 . /-, Nolim Fii II. 4 t, , MIK 711 .: ,,,,„,, \ ...,,, • r _ _ _.-- __-- �Z. —_— 4 1 ma 1 F a 1 1 1 -- ----- . J It 9, 1 1 i l l i 1; 1 ` 1 LE 11 1 1 11 i 4 ti 1p i d 1 1 1 x – `j 11.1 1 1 ��• 11 1 i 1 11 11111‘1;11111 1 1 11111 1 1 1 1 ' 'l 11 1 1 t 11 11 i 14 'l 1 1 1 111 ii 1 1 1111 1I 1 1111 1 i [ ,11111 —^ 3 1 1.111 , I 1 r ' 1 1 1 1 1 1 1 ' 11 \ 1/j 1 _1 11 1 1 1 i 3 1 l it 1 1 f 1 11 111111 l 1 I I 1 l 1 11 1 1 1 l 1 1 (C STEVENS ENGINEERS 1135h LIVINGSI'ONE ROAD HUDSON. WISCONSIN 54015 1fWW.STEVENSENGINEE RS.CO M (e 1)4315 -8x75 (715) 8E --5$18 FAX:(715 }398 -5879 SHEET DESCRIPTION GRADING, DRAINAGE AND EROSION CONTROL PLAN FOX HOLLOW P.U.D OAK PARK HEIGHTS, MN 1 HEREBY CERTIFY THAT THIS PLAN WAS PREPARED BY ME OR UNDER MY DIRECT SUPERVISION AND THAT 1 AM A OULY REGISTERED PROFESSIONAL ENGINEER UNDER THE LAWS OF THE STATE OF M €NNESOTA. SCOTT ►_ WARD REG, NO. 4C921 PATE DRAWN BY CHECKED BY TES SAW PROJECT ENG".NEER SAW PROJECT NO. 5046 DATE FILE NAME 6/9/04 REVISIONS 7/20/04 DETAILS 1 SliV130 1 /0Z /L SNOISV 3L1 va/s /9 91705 MVS sr1 I VN 31LJ alma ON 132,3+:1 MVS 2133N:ON3 103f 012d AB 03 NO3H0 AB WNW 3,0 LZFO, OIJVM 'V 11005 'ON '032! 'ViOSNiirt 3O 31Vis iii io siwwi 31ii 830Nn 21331 1VN0iSS34O8d 133N3151038 Aini V 1h1+ 1 1t+Hi (INV NOISlA233df1S 1032110 A}Y 830Nn 2'iO 3• AB 038Vd3l1d SVM NVId SIFii 1VH1 A3L1i33 AB3i3H 1 VLOS3NNIW `S1H013H 51Zivd 7Lbo O'ft'd MO110H XO.d Nd1d Al 111J fl aNd lnoxd1 :pis NOiadI80S30 133HS Bag - ees[91L)ixy ' 6T -aes (514) s ioi - [�ss3 xaa •si 3ZN1 O NasN gnsis •1uL►L 9T0'Y9 3d1513'OOSLi 'NOsann QVOH 9g9I s'aaaNIDNa SM[AaIS APPENDIX A MODELING RESULTS FOR EXISTING CONDITIONS Commercial Outlot \ Subcat Reach ••■•••■•■•••••••••■••••■■••■•••■•ry,,, •-••-••••••- •••` •• • Twinhome Area ond Link Pond 1 4R EpiZng 36 in Pipe 4_ CoLD t) 0 Drainage Diagram for East Oaks Exist 2004 Prepared by {enter your company name here} 3/4/2004 HydroCADID 7.00 sfn 002721 © 1986-2003 Applied Microcomputer Systems East Oaks Exist 2004 Prepared by Stevens Engineers - JPD ft droCAD® 7.00 sin 002721 © 1986-2003 A • • lied Microcom uter stems Type 11 24 1 Year Rainfall=2.40" Page 1 3/5/2004 9:09:34 AM Time span=5.00-20.00 hrs, dt=O.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-ind method Subcatchment 18: Commercial Outlot Subcatchment 2S: Twinhome Area Runoff Area=2.330 ac Runoff Depth=0.35" Flow Length=750' Tc=9.8 min CN=70 Runoff=1.20 cfs 0.069 af Runoff Area=5.970 ac Runoff Depth=0.57" Tc=10.0 min CN=76 Runoff=5.42 cfs 0.281 af Reach 4R: Existing 36 in Pipe Peak Depth=0.31' Max Vel=8.6 fps Inflow=3.35 cfs 0.339 af D=36.0" n=0.013 L=500.0' 5=0.0500 '1' Capacity=149.14 cfs Outflow=3.29 cfs 0.339 af Pond 3P: Pond 1 Peak Elev=842.44 Storage=5,553 cf Inflow=5.42 cfs 0.281 af 21.0" x 98.0' Culvert Outflow=2.62 cfs 0271 af Total Runoff Area = 8.300 ac Runoff Volume = 0.350 af Average Runoff Depth = 0.511" East Oaks Exist 2004 Type 11 24 hr 1 Year Rainfall =2.4O" Prepared by Stevens Engineers - .BPD Page 2 H droCAD® 7.00 s/ 002721 © 1986 -2003 A Tied Kamm_ uter S stems 315 2004 9:09:34 AM Subcatchment 'IS: Commercial Outlot Runoff 1.20 cfs 12.04 hrs, Volume= 0.009 af, Depth= 0.35" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 1124 -hr 1 Year Rainfall=2.40" Area ac CN Descri * tion 0.120 98 Paved parking & roofs 2210 69 50 -75% Grass cover Fair HSG B 2.330 70 Weighted Average 0 IL Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 5.5 300 0.0670 3.3 450 0.0530 9.8 750 Total 1 6 0.8 Sheet Flow, Outlot Fallow n= 0.050 P2= 2.80" 2.3 Shallow Concentrated Flow, Outlot Nears Bare & Unfilled Kv= 10.0 f Subcatchment IS: Commercial Outlot 10 11 Hydrograph 1.20 cfs 12 13 14 Time (hours) Type 1124-hr 1 Year RainfaII=24O" Runoff Area =2.330 ac Runoff Volume=0069 of Runoff Depth=O.35" Flow Length =750' TC=9R8 min CN =70 15 r 16 17 Are 18 19 20 East Oaks Exist 2004 Prepared by Stevens Engineers - JPD H droCAD® 7.00 sin 002721 ©1986 -2003 A + •lied Microcom . uter S stems Subcatchment 2S: Twinhome Area Runoff 5.42 cfs 12.03 hrs, Volume= 0.281 af, Depth= 0.57" Runoff by SCS TR -20 method, U1-1=SCS, Time Span= 5.00-29.00 hrs, dt= 0.05 hrs Type ti 24-hr 1 Year Rainfall =2.40" Area ac CN Descri .tion 2.390 98 Paved parking & roofs 3.480 61 >75% Grass cover, Good, HSG B 0.100 83 Pond 5.970 76 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 w 0 6 5 4 3 2 0 5 6 Subcatchment 28: Twinhome Area Hydrograph Type 1124 -hr 1 Year Rai nfaI1=24O " Runoff Area =5.970 ac Runoff VoIume=O281 af Runoff Depth�57" Tc1OO min CN =76 10 11 12 13 14 Time (hours) Direct Entry, Twinhome Area 15 16 Type 11 24-hr 1 Year Rainfall =2.40" Page 3 3/5/2004 9 :09 :34 AM 17 18 19 20 0 Runoff East Oaks Exist 2004 Type 1124 -1 r 1 Year Rainfall=2.40" Prepared by Stevens Engineers - JPD Page 4 H doCAD0 7.00 s/n 00? 2 988 -2003 A fled ■fcrocom uter S sterns 3/5/2004 9:09:34 AM [52] Hint: inlet conditions not evaluated Inflow Area = 8.300 ac, Inflow Depth = 0.49" for 1 Year event Inflow = 3.35 cfs ac 12.11 hrs, Volume= 0.339 of Outflow = 3.29 cfs a3 12.15 hrs, Volume= 0.339 af, Atten= 2 %, Lag= 2.1 min Routing by Stor Ind+Trans method, Time Span= 5.0020.00 hrs, dt= 0.05 hrs Max. Velocity= 8.6 fps, Min. Travel Time= 1.0 min Avg. Velocity = 4.4 fps, Avg. Travel Time= 1.9 min Peak Depth= 0.31' @ 12.12 hrs Capacity at bank full= 149.14 cfs Inlet Invert= 815.00', Outlet Invert= 790.00' 36.0" Diameter Pipe n= 0.013 Length= 500.0' Slope= 0.0500 '1' 3 ) 2 0 1 7 Reach 4R: Existing 36 in Pipe Reach 4R: Existing 36 in Pipe Hydrograph 3.35 cfs 3.29cfs F AtereedWid I nflow Area=&300 ac Peak Depth=O31' Max VeI=86 fps D= 36.0 ° ' n =0.013 L= 500.0 S= 0.0500 '/' Capacity= 149.14 cfs iore r. ". 10 11 1'2 13 14 Time (hours) 15 16 17 18 1 E 9 20 0 Inflow 0 outflow East Oaks Exist 2004 Type 11 244ir 1 Year Rain1all=2. 40" Prepared by Stevens Engineers - JPD Page 5 HydroCAD® 7.00 sin 002721 01986 -2003 A lied Mi�rocorn uter S stems 3!5/2004 9 :09 :35 AM Pond 3P: Pond 1 Inflow Area = 5.970 ac, Inflow Depth = 0.57" for 1 Year event Inflow = 5.42 cfs @ 12.03 hrs, Volume= 0.281 af Outflow = 2.62 cfs @ 12.16 hrs, Volume= 0.271 af, Atten= 52 %, Lag= 7.9 min Primary = 2.62 cfs @ 12.16 hrs, Volume= 0.271 af Routing by StorrInd method, Time Span= 5.99-20.99 hrs, dt= 0.05 hrs Starting Elev= 841.73' Surf.Area= 3,597 sf Storage= 2,464 cf Peak Elev= 842.44' a@ 12.18 hrs Surf.Area= 4,343 sf Storage= 5,553 cf (3,089 cf above start) Plug -Flow detention time= 117.3 min calculated for 0.214 af (76% of inflow) Center-of-Mass det. time= 20.4 min ( 840.7 - 820.3 ) Invert Avail.Stora • a Stora. a Descri • tion 1 841.00' 28,098 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store feet s -ft cubicfeet cubic-feet 841.00 2,895 0 0 842.00 3,856 3,376 3,376 6 844.00 6,080 9,936 13,312 846.00 8,706 14,786 28,098 # Routin 1 Primary Invert Outlet Devices 841.73' 21.0" x 98.0' long Culvert RCP, end - section conforming to fill, Ke= 0.500 Outlet Invert= 819.97' 8= 0.2220 '1' n= 0.013 Cc= 0.900 Primary OutFlow Max =2.59 cfs a 12.16 hrs HW =842.43' (Free Discharge) t_1 cuIvert (Inlet Controls 2.59 cfs @ 2.9 fps) East Oaks Exist 2004 Prepared by Stevens Engineers - JPD �roCAD® 7.00 sin 002721 © 1986-2003 Applied Microcomputer Systems Wean reeirreernordWA Pond 3P: Pond 1 Hydrograph 5.42 cfs F 2.62 cfs Time (hours) 10 11 12 13 14 15 16 17 Type 11 24 hr 1 Year Rainfall =2.40" Page 6 3/5/2004 9:09 :35 AM nflow Area=5.970 ac Peak EIev=842.44' Storage =5,553 cf 21,0" x 98.0' Culvert ea rear ,4 : 18 19 20 Inflow 0 Primary East Oaks Exist 2004 Type 1124 100 Year Rainfall=5.90" Prepared by Stevens Engineers - JPD Page 7 H droCAD 7.00 sin 002721 © 1986-2003 A. .lied Microcom uter S stems 3/5/2004 9:09:35 AM Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 'IS: Commercial Outlot Subcatchment 28: Twinhome Area Runoff Area=2.330 ac Runoff Depth=2.50" Flow Length=750' Tc=9.8 min CN=70 Runoff=9.70 cfs 0.485 af Runoff Area=5.970 ac Runoff Depth=3.04" Tc=10.0 min CN=76 Runoff=29.70 cfs 1.514 af Reach 4R: Existing 36 in Pipe Peak Depth=0.82' Max Vel=15.6 fps Inflow=24.44 cfs 1.977 af D=36.0" n=0.013 L=500.0' S=0.0500 '1' Capacity=149.14 cfs Outflow=24.28 cfs 1.976 af Pond 3P: Pond 1 Peak Elev=844.58' Storage=17,596 cf Inflow=29.70 cfs 1.514 af 21.0" x 98.0' Culvert Outhow=16.27 cfs 1.493 af Total Runoff Area = 8.300 ac Runoff Volume = 1 .999 af Average Runoff Depth = 2.89" East Oaks Exist 2004 Type 1124 -hr 100 Year Rainfall =5.90" Prepared by Stevens Engineers - JPD Page 8 H droCAD® 700 stn 002721 © 1 986 -2003 As died Microcom.uter S stems 3/5/2004 9:09 :35 AM 6.5 300 0.0670 3.3 450 0.0530 9.8 750 Total 10 9 5 6 9 0.8 Subcatchment I S: Commercial Outlot Runoff 9.70 cfs 12.02 hrs, Volume= 0.485 af, Depth= 2.50" Runoff by SCS TR -20 method, UH=SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 1124 -hr 100 Year Rainfall =5.90" Area ac CN Descri tion 0.120 98 Paved parking & roofs 2.210 69 50 -75% Grass cover Fair HSG B 2.330 70 Weighted Average Tc Length Slope velocity Capacity Description min feet ftlft ft/sec cfs Sheet Flow, Outlot Fallow n= 0.050 P2= 2.80" 2.3 Shallow Concentrated Flow, Outlot Near! Bare & Untitled Kv= 10.0 f * s Subcatchment 1S: Commercial Outlot iiydrograph 10 11 12 13 14 Time (hours) 15 9.70 cfs Type 1124 -hr 100 Year Rai nfaH=59O" Runoff Area -2.330 ac Runoff Volurne=O.485 of Runoff Depth=25O" Flow Length=750v Tc98 min CN =70 16 17 18 19 20 0 Runoff East Oaks Exist 2004 Type 1124 -hr 100 Year Rainfall =5.90" Prepared by Stevens Engineers - JPD Page 9 HydroCAD ®7.00 sin 002721 © 1986 --2003 Applied 111licrocom uter stems 3/5/2004 9:09:35 AM Subcatchment 2S: Twinhome Area Runoff = 29.70 cfs @ 12.01 hrs, Volume= 1.514 af, Depth= 3.04" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 11 24 -hr 100 Year Rainfall= 5.90" Area (ac) CN Description 32 30 28 25'. 24 22 20= 0 8 . 18 �.. 14 12 . 10 8 6 2- . 0 2.390 98 3.480 61 0.100 83 5 6 7 8 9 Paved parking & roofs >75% Grass cover, Good, HSG B Pond 5.970 76 Weighted Average 7c Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 Hydrograph Direct Entry, Twinhome Area Subcatchment 28: Twinhome Area Type II 24 -hr 100 Year RainfaIl=59O" Runoff Area=&970 ac Runoff VoIume=t514 of Runoff Depth=3O4" Tc=10.0 min CN=76 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 0 Runoff East Oaks Exist 2004 Type 11244ir 100 Year Rainfa11 =5.9O" Prepared by Stevens Engineers - JPD Page 10 jydroCAD® 7.00 sin 002721 © 1986 -2003 A lied Microcorn ufer S sums 315/2004 9:09:35 AID [52] Hint: Inlet conditions not evaluated Reach 4R: Existing 36 in Pipe Inflow Area = 8.300 ac, Inflow Depth = 2.80" for 100 Year event Inflow = 24.44 cfs @ 12.05 hrs, Volume= 1.977 of Outflow = 24.28 cfs @ 12.08 hrs, Volume= 1.978 af, Atten= 1%, Lag= 1.0 min Routing by Stor - Ind +Trans method, Time Span= 5.0020.00 hrs, dt= 0.05 hrs Max. Velocity= 15.6 fps, Min. Travel Time= 0.5 min Avg. Velocity = 6.0 fps, Avg. Travel Time= 1.4 min Peak Depth= 0.82' © 12.05 hrs Capacity at bank full= 149.14 cfs Inlet Invert= 815.00', Outlet Invert= 790.00' 36.0" Diameter Pipe n= 0.013 Length= 500.0' Slope= 0.0500 `1' 26 24 22 20 18 16 12 10.1 Q i 8 .i 6 - - 4 2 0 5 Reach 4R: Existing 36 in Pipe Hydrograph 24.44 cfs 24.2$cfs r Inflow Area =8.300 ac Peak Depth=O82' Max Vei=i 56 fps D= 36.0" n =0.013 L= 500.0' S= 0.0500 '/' Capacity1 491 4 cfs 10 11 1'2 13 14 Time (hours) 15 16 17 18 19 20 inflow Outflow East Oaks Exist 2004 Type 1124 -hr 100 Year Rainfall =5.90" Prepared by Stevens Engineers - ,BPD Page 11 H droCAD® 7.00 sin 002721 © 1986-2003 A. • lied Microcam. uter S stems 3/5/2004 9:09:35 AM Pond 3P: Pond 1 Inflow Area = 5.970 ac, Inflow Depth = 3.94" for 100 Year event Inflow = 29.76 cfs @ 12.01 hrs, Volume= 1.514 of Outflow = 16.27 cfs @ 12.13 hrs, Volume= 1.493 af, Atten= 45 %, Lag= 6.9 min Primary = 16.27 cfs @ 12.13 hrs, Volume= 1.493 af Routing by Star Ind method, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Starting Elev= 841.73' Surf.Area= 3,597 sf Storage= 2,464 cf Peak Elev= 844.58' @ 12.13 hrs Surf.Area= 6,841 sf Storage= 17,596 cf (15,132 cf above start) Plug -Flow detention time= 40.3 min calculated for 1.431 af (95% of inflow) Center-of-Mass det. time= 14.6 min ( 799.1 - 784.5 ) # Invert Avail.Stora. a Stora.. a Descri. Lion 841.00' 841.00 2,895 842.00 3,856 844.00 6,080 846.00 8,706 28,098 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (s cu ft) (bic -feet) (cubic -feet) 0 3,376 9,936 14,786 0 3,376 13,312 28,098 # Routin Invert Outlet Devices 1 Primary 841.73' 21.0" x 98.0' long Culvert RCP, end - section conforming to fill, Ke= 0.500 Outlet Invert= 819.97' S= 0.2220 '1' n= 0.013 Cc= 0.900 Primary OutFlow PVIax =16.21 cfs @ 12.13 hrs FEW = 844.56' (Free [discharge) t--1mCulvett (Inlet Controls 16.21 cfs © 6.7 fps) East Oaks Exist 2004 Type 1124-hr 100 Year Rainfall=5.90" Prepared by Stevens Engineers - JPD Page 12 HydroCAD® 7.00 sin 002721 © 1 986-2003Apj1ied Microcom Stems 3/5/20 440 Pond 3P: Pond 1 Hydrograph [29.79 c Ii1/1 allow Area=5.970 ac it II Peak Elev=844.58' Storage=17,596 cf 1 „ 21.0" x 98.0' Culvert I 16.27 cis 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 East Oaks Exist 2004 Type 1124-hr 2 Year Rainfall=2.80" Prepared by {enter your company name here} FI chy_s/n 002721 © 1986-2003Applied Microcom uter S stems 3/5/2004 846 845 844 4 it 843 842 841 0 2 Stage-Discharge Pond 3P: Pond 1 10 12 Discharge (cfs) 14 16 18 20 East Oaks Exist 2004 Type 1124- hr 2 Year Rainfall =2.80" Prepared by {enter your company name here} H droCA 7.00 sln 002721 a 1986.2003 A hed 11 k rocom utor S Stem 3/5/2004 846 845 r-. 844 c 0 843 842 .. 841 0 500 1 ,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000 7,500 8,000 8,500 5,000 p Data Pond 3P: Pond 1 Stage - Area -Storage 1 0,000 1 5,000 Storage (cubic. feet) 20,000 25,000 Surface 0 Storage APPENDIX B MODELING RESULTS FOR PROPOSED CONDITIONS Commercial Outlot ff ie < Subcat> Reach \ i: 2S 7 ; \,_„,„,1 Twinhome Area on Link 3P Pond 1 4R (sting 36 in Pipe Pko b o uS Drainage Diagram for East Oaks Proposed 2004 Prepared by Stevens Engineers -- JPD 3/512004 HydroCAD® 7.00 sin 002721 © 1986-2003 Applied Microcomputer Systems East Oaks Proposed 2004 Prepared by Stevens Engineers - JPD H droCAD® 7.00 sin 002721 © 1986-2003 A. •lied Microcom Type 1124 2.5 in rainfall Rainfall=2.50" Page 2 uter S stems 3/5/2004 9:28:16 AM Time span=5.00-20.00 hrs, dt=O.03 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by StorInd+Trans method - Pond routing by Stor-Ind method Subcatchment 'IS: Commercial Outlot Subcatchment 2S: Twinhome Area Runoff Area=2.330 ac Runoff Depth=0.86" Flow Length=750' Tc=5.2 min CN=81 Runoffr4.02 cfs 0.166 af Runoff Area=5.970 ac Runoff Depth=0.62" Tc=10.0 min CN=76 Runoff=6.08 cfs 0.309 af Reach 4R: Existing 36 in Pipe Peak Depth=0.37' Max Vel=9.6 fps Inflow=4.75 cfs 0.451 af D=36.0" n=0.013 L=500.0 S=0.0500 '1' Capacity=149.14 cfs Outflow=4.71 cfs 0.450 af Pond 3P: Pond 1 Peak Elev=842.93' Storage=17,487 cf Inflow=9.40 cfs 0.475 af Outflow=4.75 cfs 0.451 af Total Runoff Area = 8.300 ac Runoff Volume = 0.475 af Average Runoff Depth = 0.69" East Oaks Proposed 2004 Type 11 24 -hr 2.5 in rainfall Rainfall 2.50" Prepared by Stevens Engineers JPD Page 3 H droCAD® 7.00 sin 002721 ©1 986 --2003 A. 'lied Microcom • uter S stems 3/512004 9:28:16 AM Subcatchment 18: Commercial Out lot Runoff 4.02 cfs @a 11.97 hrs, Volume= 0.166 af, Depth= 0.86" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00-20.00 hrs, dt= 0.03 hrs Type 1124 -hr 2.5 in rainfall Rainfall =2.50" Area ac CN Descri•tion ................... ........_...................... ....... ..... .......... 1.240 98 Paved parking & roofs 1.090 61 >75% Grass cover Good HSG B 2.330 81 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs r° 1.9 300 0.0670 3.3 450 0.0530 5.2 750 Total 1 6 2.6 Sheet Flow, Outlot Smooth surfaces n= 0.011 P2= 2.80" 2.3 Shallow Concentrated Flow, Outlot Neari Bare & U ntilled Kv = 10.0 f. s Subcatchment IS: Commercial Outlot Hydrograph 4.02 cis Atarde4rierierzogr ArdAz 10 11 12 13 14 Time (hours) Type 1124-hr 2.5 in rainfall RainfaII=25O" Runoff Area =2.330 ac Runoff Volume=O.166 of Runoff Depth=O86" Flow Length =750' Tc=52 min CN =81 15 16 17 18 19 20 0 Runoff East Oaks Proposed 2004 Type 11 24- hr 2.5 in rainfall Rainfall =2. 0" Prepared by Stevens Engineers - JPD Page 4 HydroCAD® 7.00 s/n 002721 © 1 986 -2003 A Tied Mk r000m uter S stem 3I5f2994 9:28:16 AM Subcatchment 2S: Twinhome Area Runoff 6.08 cfs @ 12.63 hrs, Volume= 0.309 af, Depth= 9.62" Runoff by SCS TR-20 method, UM=SDS, Time Span= 5.09 -20,99 hrs, dt= 9.43 hrs Type 1124 -hr 2.5 in rainfall Rainfall =2,56" Area ac CN Descri . tion 2.399 98 Paved parking & roofs 3.430 61 >75% Grass cover, Good, MSG B 0.150 85 Pond 5.970 76 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 5 5 0 it 3 2 0 5 10 11 Hydrograph Direct Entry, Twinhome Area Subcatchment 28: Twinhome Area driffatanar die." 6.08 cfs Type II 24 -hr 2.5 in rainfall RainfaII=25O" Runoff Area5970 ac Runoff Volurne=OE309 af Runoff Depth=OE62 °' Tc=IOM min CN =76 12 13 14 15 Time (hours) 16 17 18 19 20 East Oaks Proposed 2004 Prepared by Stevens Engineers - JPD H droCAD® 7.00 sin 002721 © 1986-2003 A. 'lied Microcom [52] Hint: inlet conditions not evaluated Inflow Area = 8.300 ac, Inflow Depth = 0.65" for 2.5 in rainfall event Inflow = 4.75 cfs @a 12.12 hrs, Volume= 0.451 af Outflow = 4.71 cfs c 12.15 hrs, Volume= 9.450 af, Atten= 1%, Lag= 1.6 min Routing by Starrind +Trans method, Time Span= 5.00 -20.00 hrs, dt= 0.03 hrs Max. Velocity= 9.6 fps, Min. Travel Time= 0.9 min Avg. Velocity = 4.4 fps, Avg. Travel Time= 1.9 min Peak Depth= 0.37' a@ 12.13 hrs Capacity at bank full= 149.14 cfs Inlet Invert= 815.00', Outlet Invert= 790.00' 30.0" Diameter Pipe n= 0.013 Length= 500.0' Slope= 0.0500 0 L 5. l '" , Reach 4R: Existing 36 in Pipe Reach 4R: Existing 36 in Pipe Hydrograph 44.75 cfs c C4.7l cfs k 10 11 12 13 14 Time (hours) Type 11 24 -hr 2.5 in rainfall Rainfall=2.50" Page 5 uter s stems 3/5/2004 9 :28 :16 AM Inflow Area = &300 ac Peak Depth=O.37' Max Ve1=96 fps D=3&OIv n =0.013 L=500.0 8 =0 0500 'Iv Capacity 4914 cfs 15 16 ,::'✓.: `:: ;•'.f'•:;': a' ;r�` f: �.. °' 7Z;":77"7- dsloordmoze 17 18 19 20 Inflow C Outflow East Oaks Proposed 2004 Prepared by Stevens Engineers JPD H droCAD® 7.00 sin 002721 © 1986 A. tlied Microcom Inflow Area = Inflow Outflow Primary Routing by StorInd method, Time Span= 5.00-20.00 hrs, dt= 0.03 hrs Starting Elev= 842.00' Surf.Area= 5,000 sf Storage= 11,895 cf Peak Elev= 842.93' c 12.12 hrs Surf.Area= 5,919 sf Storage= 17,487 of (5,592 cf above start) Plug-Flow detention time= 253.4 min calculated for 0.178 af (37% of inflow) Center-of-Mass det. time= 24.0 min ( 836.2 - 812.2 ) Invert Avail.Stora e Stora e Descri tion 838.00' Elevation Surf.Area Inc.Store Cum.Store feet s cubic-feet 1 838.00 2,000 840.00 3,000 841.00 842.00 844.00 846.00 Routin Primary 2 Device 1 3 Device 1 Pond 3P: Pond 1 8.300 ac, Inflow Depth = 0.69" for 9.40 cfs @ 12.00 hrs, Volume= 4.75 cfs © 12.12 hrs, Volume= 4.75 cfs 12.12 hrs, Volume= 2,895 5,000 6,966 8,934 39,761 cf Custom Stage Data (Prismatic) Listed below 0 5,000 5,000 2,948 7,948 3,948 11,895 11,966 23,861 15,900 39,761 uter S stems Invert Outlet Devices 842.00' 24.0" x 90.0 long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 820.00' S= 0.2444 '1' n= 0.013 Cc= 0.900 840.00' 15.0" Vert. Orifice/Grate C= 0.600 840.00' 15.0" Vert. Orifice/Grate C= 0.600 Type 1124-hr 2.5 in rainfall Rainfall=2.50" Page 6 3/5/2004 9:28:16 AM 2.5 in rainfall event 0.475 af 0.451 af, Atten= 50%, Lag= 7.3 min 0.451 af Primary OutFlow Max=4.72 cfs 12.12 hrs HW=842.93' (Free Discharge) t-1=Culvert (Inlet Controls 4.72 cfs 3.3 fps) -2=Orifice/Grate (Passes < 5.70 cfs potential flow) --3=Orifice/Grate (Passes < 5.70 cfs potential flow) East Oaks Proposed 2004 Prepared by Stevens Engineers - JPD H droCADe 7.00 sin 002721 © 1986-2003 At *lied Microcom 10 direffed 8 Pond 3P: Pond 1 Hydrograph 9.49cfs 1 4.75cfs uter S stems Type 11 24-hr 2.5 in rainfall Rainfall =2.5O" Page 7 3/5/2004 9 :28 :17 AM nflow Area=8.3OO ac Peak EIev=842.9 3' Storage = 17,487 cf r zed ret redr 00.A0 re a roz fe r, e re r 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 0 Inflow n Primary East Oaks Proposed 2004 Type 11 24-hr 10 Year Rainfall=4.10" Prepared by Stevens Engineers JPD Page 8 H droCAD® 7.00 sin 002721 © 1986 A. .lied Microcom • uter S stems 3/5/2004 9:28:17 AM Time span=5.00-20.00 hrs, dt=0.03 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: Commercial Out lot Subcatchment 2S: Twinhome Area Runoff Area=2.330 ac Runoff Depth=2.04" Flow Length=750' Tc=5.2 min CN=81 Runoff=9.34 ofs 0.396 af Runoff Area=5.970 ac Runoff Depth=1.66" Tc=10.0 min CN=76 Runoff=16.65 cfs 0.825 af Reach 4R: Existing 36 in Pipe Peak Depth=0.65' Max Vel=13.6 fps Inflow=15.53 cfs 1.187 af D=36.0" n=0.013 L=500.0' S=0.0500 Capacity=149.14 cfs Outflow=15.47 cfs 1.185 af Pond 3P: Pond 1 Peak Elev=844.05' Storage=24,295 cf Inflow=24.51 cfs 1.221 af Outflow=15.53 cfs 1.187 af Total Runoff Area = 8.300 ac Runoff Volume = 1 .221 af Average Runoff Depth = 1 .77" East Oaks Proposed 2004 Type 1124 --hr 10 Year Rainfall =4.10" Prepared by Stevens Engineers JPD Page 9 H d roCADC� 7.OD stn 002721 © 986 -2 003 Applied Microcomputer Systems 3/5/2004 9 :28:17 AM Subcatchment 1 s: Commercial Outlot Runoff 9.34 cfs @a 11.98 hrs, Volume= 0.398 af, Depth= 2.04" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.03 hrs Type 1124-hr 10 Year Rainfall =4.10" Area ac CN Descri • tion 1.240 98 Paved parking & roofs 1 .090 61 >75% Grass cover Good HSG E3 2.330 81 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 1.9 300 0.0670 3.3 450 0.0530 5.2 750 Total 2 .G Sheet Flow, Outlot Smooth surfaces n= 0.011 P2= 2.80" 2.3 Shallow Concentrated Flow, Outlot Nearl Bare & Untitled Kv= 10.0 f. s Subcatchment I S: Commercial Outlot fHydrograph 11 12 13 14 15 Time (hours) Type 11 24 -hr 10 Year Rai nfafl=4. 10" Runoff Area -2.330 ac Runoff Voiume=�396 of Runoff Depth Flow Length =750' Tc=52 min CN =81 16 17 18 19 20 0 Runoff East Oaks Proposed 2004 Type 1124 -fir 10 Year Rainfall =4.10" Prepared by Stevens Engineers - JPD Page 10 H droCAD® 71)0 s/ 002721 © A iied Microcom uter 5 stems 3/5/2004 9 :28 :17 AM Subcatchment 28: Twinhome Area Runoff = 15.05 cfs @ 12.02 hrs, Volume= 0.325 af, Depth= 1.66" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.03 hrs Type 1124 -hr 10 Year Rainfall =4.10" Area ac Ch! Descri • tion 2.390 98 Paved parking & roofs 3.430 61 >75% Grass cover, Good, HSG B 0.150 85 Pond 5.970 76 Weighted Average 1"c Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 10.0 5 6 7 8 9 Direct Entry, Twinhome Area Subcatchment 28: Twinhome Area Hydrograph 10 11 12 13 14 Time (hours) Type 11 24 -hr 10 Year RainfalI=4M1 0v Runoff Area597O ac Runoff Voiume=O825 of Runoff Depth=1 .66" Tc10 0 min CN =76 15 16 400," diMr4Or 17 18 19 20 El Runoff East Oaks Proposed 2004 Type 1124 -hr 10 Year Rainfall =4.10" Prepared by Stevens Engineers - JPD Page 11 H drOCAD 7 7.UU s/n 986 -20 A lied Microcom uter S stem 3/5/2004 9:28:17 AM [52] Hint: Inlet conditions not evaluated Inflow Area = 8.300 ac, Inflow Depth = 112" for 10 Year event Inflow = 15.53 cfs a 12.09 hrs, Volume= 1.187 of Outflow = 15.47 cfs @ 12.11 hrs, Volume= 1.185 af, Atten= O %, Lag= 1.1 min Routing by Stor Ind +Trans method, Time Span= 5.40-20.00 hrs, dt= 0.03 hrs Max. Velocity= 13.6 fps, Min. Travel Time= 0.6 min Avg. Velocity = 5.1 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.65' @ 12.09 hrs Capacity at bank full= 149.14 cfs Inlet Invert= 815.00', Outlet Invert= 790.00' 30.0" Diameter Pipe n = 0.013 Length= 500.0' Slope= 0.0500 7' To Li 17 16i 15 14 13 12 11 10 . 9 . 7 Reach 4R: Existing 36 in Pipe Reach 4R: Existing 36 in Pipe Hydrojraph 10 11 12 13 14 Time (hours) nflow Area =8.300 ac Peak Depth=O.65' Max VeI136 fps D= 36.0" n =0.013 L =500.0' S005Q0 Capacity=1 49. 1 4 cfs 15 18 17 18 19 20 0 Inflow Outflow East Oaks Proposed 2004 Type 1124-hr 10 Year Rainfall =4.10" Prepared by Stevens Engineers - JPD Page 12 H . droCADOD 7.00 sin 002721 © 1986 As .lied Microcosm.uter stems 3/5/2004 9:28:17 AM Inflow Area Inflow Outflow Primary Routing by StorInd method, Time Span= 5.00 -20.00 hrs, dt= 0.03 hrs Starting Elev= 842.00' Surf.Area= 5,000 sf Storage= 11 ,895 cf Peak Elev= 844.05' a@ 12.09 hrs Surf.Area= 7,020 sf Storage= 24,295 cf (12,400 cf above start) Plug -Flow detention time= 110.0 min calculated for 0.914 af (75% of inflow) Center-of-Mass det. time= 17.0 min ( 809.6 - 792.6 ) # Invert Avaii.Stora * e Stora. a Descri . tion 1 841.00 842.00 844.00 846.00 838.00' Elevation Surf.Area Inc.Store Cum.Store feet s -ft cubic -feet cubic -feet 838.00 2,000 840.00 3, 000 # Routin Primary 2 Device 1 3 Device 1 8.300 ac, Inflow Depth = 1.77" 24.51 cfs a 11.99 hrs, Volume= 15.53 cfs @ 12.09 hrs, Volume= 15.53 cfs 12.09 hrs, Volume= 2,895 5,000 6,966 8,934 Pond 3P: Pond 1 0 0 5,000 5,000 2,948 7,948 3,948 11,895 11,966 23,861 1 5, 900 39,761 for 10 Year event 1.221 af 1.187 af, Atten= 37 %, Lag= 5.6 min 1.187 af 39,761 cf Custom Stage Data (Prismatic) Listed below Invert Outlet Devices 842.00' 24.0" x 90.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 820.00' S= 0.2444 '1' n= 0.013 Cc= 0.900 840.00' 15.0" Vert. Orifice/Grate C= 0.600 840.00' 15.0" Vert. Orifice/Grate C= 0.600 Primary OutFlow Max =15.50 cfs a@ 12.09 hrs HW=844.05' (Free Discharge) t._ =Cu vert (Inlet Controls 15.50 cfs c 4.9 fps) 2 =Orifice /Grate (Passes < 8.46 cfs potential flow) -3 =Orifice /Grate (Passes < 8.46 cfs potential flow) East Oaks Proposed 2004 Type 11 24-hr 10 Year Rainfall=4.10" Prepared by Stevens Engineers - JPD Page 13 H droCADO 7,00 sin 002721 © 1986-2003 A. • lied Microcom uter S stems 3/5/2004 9:28:17 AM 26 24 22 20 18 .. 16 4- 14 12. 10 8 door orzdraimrdrzdyzroodroz Pond 3P: Pond 1 Hyd rog ra ph 24.51 cft Inflow Area=8.300 ac ,) Peak Elev=844.05 Storage=24,295 cf L15.53 cfs 10 11 12 13 14 Time (hours) .44e,,,,,Art e d,.. 0)1", edrAFIVIer r- 15 16 17 18 19 20 0 inflow Primary East Oaks Proposed 2004 Prepared by Stevens Engineers - JPD H droCAD� 7.00 sin 002721 © 1986 A. died Microcom Type 11 24-hr 100 Year Rainfal1=5.90" Page 14 uter S stems 3/5/2004 9:28:17 AM • Time span=5.00-20.00 hrs, dt=0.03 hrs, 501 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment IS: Commercial Out lot Subcatchment 2S: Twinhome Area Runoff Area=2.330 ac Runoff Depth=3.53" Flow Length=750' Tc=5.2 min CN=81 Runoff=15.71 cfs 0.686 af Runoff Area=5.970 ac Runoff Depth=3.04" Tc=10.0 min CN=76 Runoff=30.10 cfs 1.514 af Reach 4R: Existing 36 in Pipe Peak Depth=0.78' Max Ve1=15.1 fps Inflow=21.92 cfs 2.156 af D=36.0" n=0.013 L=500.0 S=0.0500 Capacity=149.14 cfs Outflow=21.88 cfs 2.154 af Pond 3P: Pond 1 Peak Elev=845.44' Storage=35,301 cf Inflow=43.44 cfs 2.199 af Outflow=21.92 cfs 2.156 af Total Runoff Area = 8.300 ac Runoff Volume = 21 99 af Average Runoff Depth = 318" East Oaks Proposed 2004 Type 1124 -hr 100 Year Rainfall =5.90" Prepared by Stevens Engineers - JPD Page 15 H droCAD® 7.00 sin 002721 © 1986-2003 A. 9:28:17 9 I ed Microcom uter S stems 3/5/2004 AM Subcatchment 7S: Commercial Outlot Runoff 15.71 cfs @ 11.96 hrs, Volume= 0.686 af, Depth= 3.53" Runoff by SCS TR -20 method, UH=SCS, Time Span= 5.99 -20.00 hrs, dt= 0.03 hrs Type 11 24 -hr 100 Year Rainfall=5.90" Area ac CN Descri • tion 98 Paved parking & roofs 61 >75% Grass cover Good HSG 13 2.330 81 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 17- 16 :. 15 - 14 13 _ 12 : 11 10 _. LL 8 7 1.9 .300 0.0670 3.3 450 0.0530 5.2 750 Total 5 4 3 2 1.240 1.999 2.6 Sheet Flow, Outlot Smooth surfaces n= 6.611 P2= 2.80" 2.3 Shallow Concentrated Flow, Outlot Near! Bare & Unfilled Kv= 10.0 f. s Subcatchment 1S: Commercial Outlot Hydrograph 8 9 10 11 12 13 14 15 Time (hours) Type 1124 -hr 1D0 Year RainfaII=59O" Runoff Area -2.330 ac Runoff Volume=O686 of Runoff Depth=3N53" . Flow Length =750' Tc=5 2 min CN =81 A 16 17 18 19 20 C Runoff East Oaks Proposed 2004 Type 1124 -hr 100 Year Rainfall =5.90" Prepared by Stevens Engineers - JPD Page 16 jydroCAD® 7.00 sin 002721 © 1 986 -2003 A lied ll�icrocom uter 7 A11�1 Subcatchment 2S: Twinhome Area Runoff 30.10 cfs c 12.02 hrs, Volume= 1.514 af, Depth= 3.04" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.03 hrs Type 1124 -hr 100 Year Rainfall=5.90" Area ac CN Descri tion 2.390 98 Paved parking & roofs 3.430 61 >75% Grass cover, Good, HSG 13 0.150 85 Pond 5.970 76 Weighted Average Tc Length Slope Velocity Capacity Description _ (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 32 30 28 26 24 22 20 0 18 a 16 �. 14 .: 12 10 8 6 4 0 .. 5 6 8 10 Hydrograph Direct Entry, Twinhome Area Subcatchment 2S: Twinhome Area 400' AriMeirdriV 4 30.10 cfs Type 11 24hriOO Year Rainfall= 5.90" Runoff Area=5.970 ac RunoffVolume=t514. af Runoff Depth304" Tc=10O min CN =76 11 12 13 14 Time (hours) 15 16 17 18 19 20 Runoff East Oaks Proposed 2004 Type 1124-hr 100 Year R ainfall =5.90" Prepared by Stevens Engineers - JPD Page 17 H droCAD® 7.00 sin 002721 ©1 986 --2003 A. + lied Microcom • uter S stems 3/512004 9 :28:17 AM [52] Hint: Inlet conditions not evaluated Inflow Area = 8.300 ac, Inflow Depth = 3.12" for 100 Year event Inflow = 21.92 cfs @ 12.11 hrs, Volume= 2.158 of Outflow = 21.88 cfs © 12.13 hrs, Volume= 2.154 af, Atten= 0 %, Lag= 1.0 min Routing by Stor Ind +Trans method, Time Span= 5.00 -20.00 hrs, dt= 0.03 hrs Max. Velocity= 15.1 fps, Min. Travel Time= 0.6 min Avg. Velocity = 5.7 fps, Avg. Travel Time= 1.5 min Peak Depth= 0.78' @ 12.12 hrs Capacity at bank full= 149.14 cfs Inlet Invert= 81 5.00 ', Outlet Invert= 790.00' 36.0" Diameter Pipe n= 0.013 Length= 500.0' Slope= 0.0500 `1' 24 . 22 20 18 16- 14' 12 . 10 8 6 4 2 0 5 8 10 Reach 4R: Existing 36 in Pipe Reach 4R: Existing 36 in Pipe H yd rog ra ph [ z I.ea ors Po 00 00 11 12 13 14 Time (hours) nflow Area =8.300 ac Peak Depth=0J8' Max VeI=1 5i fps D =36.0" n =0.013 L= 500.0' S= 0.0500 'I' Capacity=149.14 cfs 15 16 17 18 19 20 "l Inflow D Outflow East Oaks Proposed 2004 Prepared by Stevens Engineers - JPD H droCADO 7.00 s/n 002721 © 1986-2003 A. died Microcom uter S stems Type 11244ir 100 Year Rainfall=5.90" Page 18 3/5/2004 9:28:17 AM Inflow Area = Inflow Outflow = Primary = Routin 1 840.00 841.00 842.00 844.00 846.00 Primary 2 Device 1 3 Device 1 Pond 3P: Pond 1 8.300 ac, inflow Depth = 3.18" for 100 Year event 43.44 cfs © 11.99 hrs, Volume= 2.199 af 21.92 cfs 12.11 hrs, Volume= 2.156 af, Aften= 50%, Lag= 7.3 min 21.92 cfs @ 12.11 hrs, Volume= 2.156 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.03 hrs Starting Elev= 842.00' Surf.Area= 5,000 sf Storage= 11,895 cf Peak Elev= 845.44' c 12.11 hrs Surf.Area= 8,382 sf Storage= 35,301 cf (23,406 cf above start) Plug-Flow detention time= 77.1 min calculated for 1.879 af (85% of inflow) Center-of-Mass det. time= 16.2 min ( 796.3 - 780.1 ) s cription 1 838.00' 39,761 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store 838.00 2,000 3,000 2,895 5,000 6,966 8,934 0 5,000 2,948 3,948 11,966 15,900 0 5,000 7,948 11,895 23,861 39,761 Primary OutFlow Max=21.91 cfs @ 12.11 hrs HW=845.44' (Free Discharge) t__1 Culvert (Passes 21.91 cfs of 23.61 cfs potential flow) 11: 2=Orifice/Grate (Orifice Controls 10.95 cfs 8.9 fps) 3=Orifice/Grate (Orifice Controls 10.95 cfs 8.9 fps) Invert Outlet Devices 842.00' 24.0" x 90.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 820.00' S= 0.2444 '1' n= 0.013 Cc= 0.900 840.00' 15.0" Vert. Orifice/Grate C= 0.600 840.00' 15.0" Vert. Orifice/Grate 0= 0.600 East Oaks Proposed 2004 Prepared by Stevens Engineers - JPD H droCAD® 7.00 sin 002721 © 1 986 -2003 A. oiled Microcom 45 40 35 . 30 :? 25 0 LL 0 .. 15 10 Pond 3P: Pond 1 Hyd rog ra ph [43.44 cts 6 77=77 ` Vim` ^w .!: ; +. "�,� ,! AtarroO orgee:0 10 1 12 13 14 Time (hours) uter S stems nflow Area =8.300 ac Peak EIev=84544' Storage= 35,301 cf 15 16 Type 1124 -hr 100 Year Rainfall=5.90 Page 19 3/5/2004 9:28:17 AM $1 ; 0 2 0 2r rie:1,4 e ' 17 18 19 20 [1 Inflow 0 Primary East Oaks Exist 2004 Prepared by Stevens Engineers - JPD H droCAD® 7.00 s/n 002721 ©1 986 -2003 A. . bed Microcom • uter S stems 3/5/2004 9:22:46 AM 2 .4' Inflow Area=&300 ac Peak Depth=O82' Max VeI=1 56 fps D= 36.0" n =0.013 L= 500.0' S=OM500VP Capacity=1 49 1 4 cfs 5 Reach 4R: Existing 36 in Pipe Hyd rog ra ph 10 11 12 13 14 Time (hours) 15 Type 1124 -hr 100 Year Rainfa11 =5.90 16 17 18 19 20 Fl Inflow East Oaks Proposed 2004 Type 1124 -hr 100 Year Ra' � �nfall=5.9Q " Prepared by Stevens Engineers -. JPD jydroCAD® 7.00 sin 002721 ©1 986 -2003 A+ + lied Microcom + uter S stems 3/5/2004 9:22:14 AM .. .................. . .. .... . .......... 24 22 20 18 . 14- u g 12 10 8 6 4 .. 2 0 6 8 9 10 Reach 4R: Existing 36 in Pipe 11 Hydrograph 21 92 eft 1 Inflow Area=83OQ ac Peak Depth=O 7 Max VeI=1 D=360" 0" n=0.013 L =500 o s=0.0500 =r r Capacity=149 14 cfs 12 13 14 Time (hours) r: 15 PP � 16 17 18 19 20 fY Inflow APPENDIX C SUPPLEMENTAL DETAILS STEPS, 16' ON CENTER 50 LF 24" RCP 0.22% IE 842,00 1/4" X 1 1/2" FLAT BAR 4 - 1/2" ANCHOR BOLTS W/ CLIPS 5.0 , IE 842.00 IE 840.00 TWO (2) 15' DIA. ORIFICES NOT TO SCALE 6' THICK CONCRETE BAFFLE #5 SMOOTH BARS © 4" O.C. EACH WAY 5 LF 24' INLET CULVERT 845.44 IE 842.00