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2007-02-13 FFE Memo to BCWD Re Watershed Permit 06-30 & Attachments
Folz, Freeman, Erickson, Inc. MEMORANDUM Project: W.A.T.E Office Warehouse To.: Karen Kill - BCWD; Lisa Tillman — EOR; Karen Erickson - Bonestroo From: Vicki VanDell Date: 02 -13 -07 lila- - - - f LAND PLANNING • SURVEYING 4 ENGINEERING ti Re: Watershed Permit 06-30 The following is in response to the memo for the Browns Creek Watershed Board Meeting on February 12, 2007. • We have revised the storm sewer culvert design under the entry drive to pass the 10- year event through the pipe before overtopping Memorial Avenue. • We have increased the height of the berm around the Cold Storage building and included the Hydrocad calculations to show that the swale has adequate capacity in a 100 -year event to fully direct the water to the Kern Center Pond. • We have revised our Grading Plan to provide inlet protection at all of the 7 inlets. The detail on the sheet depicts the type of inlet protection. The permanent vegetation on the berm along the swale will be sod as noted in the sheet notes number 3. We have added a note stating the site shall be sodded within 48 hours of the final grading. If you have additional questions or comments you can reach me at 051 -439 -8833. 5620 Memorial Avenue North, Stillwater, MN 55082 4 Phone: (651) 439 -8833 4 Fax: (651) 430- 9331 4 Website: ww14•.ffe- inc.corn Brace A. Fat , LS Timothy J. Freeman, LS Todd A. Erickson, PE 1239 - 2001 Presidennr Vice President i i r. ,.. 3 3 '!.., . I% 2, . ff. r , '''''' LtOt• NOS,01111 V GC101 Oil 35.241 Wd.1.1 41VG 41:13.0 A,A .0441 221, goovat 1, NOSS Nii '111,1,1111,111_1110N II.V1,401,311. VIOS3NNIW iilLVIAIILLS 3AV 1V1110W3W OL9S - DION NW `511-013H N/lVd NVO JO AIID JSCIOH3W/V1/3DIJA0 7111M )rtfli .01.1 {D ,11.440 S3SFMcF831N] 311IM IIMIXIIVIIM ,..11411,09,23 ON1A3Nallg " Ili nNINMV NV1d Di NICIV WFUTil 1 1 - - 1 - - •31.11 ,Tosappa 'xilltuoa.ij . ioj V • 61' 41) zo 9 GRADING PLAN PROPOSED STORM SEVVER EXISTING TREES TO REMAIN ZWSS . tniv.aus . 111110N I1NBY 1,11,01,31 aNDLUNIDN1 ONINNVII , 3) ;E . 170S,10,1a VW'S] N N IW '41131VM1111S "3AV 1'41101,0N OL9S SWIM? 5.13,00 S3SINd2131N] 3"1VM V451.81.0 NW SIFIDI3H )1114/(1 WO AO AID 3S110H3/1VMBDUJO TIVM NV1d Alf] lin k) riR ‘e, 4 § / NN ath, 'zz — cs;zo tel .0?) ZS gaEZ,9GEON _ 18 t r _ t :7 i J i,...1,7 T: ,, - - - ..._, . NOMPEI CICIO1 .N.11 A, WIA3101... TM] 3, COM Arn g9 t — 90 9a./L/6 lis6 Ef,MHIS,,,II ERIS NI, H.3.11,111113 }MON 31:1SitY - IVIliMil , OZ9i V1OS3NNIW . 1131VM1111.S 3AV 1VISOW3W OL95 IIVd NVO AO kL NW SIHDI3E1 N ID 3S110HINVANADIAA0 - TIVAA Isw Z al. . ,,-. 1,, 1 wwiEw S3SI '31YM 1%511WINK.5 !WRIT/NMI DNIA31.13 ' 3.44 dVIN 3DVNIVKI CI3S0dONcl - A711#1 i 'DUI ,oslaTI. 'mut .na,/ .2.10,4 w PROPOSED DRAINAGE cu at 1 a Reach Link to Swale Swale Drainage Diagram for Zinti Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, inc. 2/13/2007 HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC Zintl Proposed 2 -13 -07 Prepared by FoIz, Freeman, Erickson, Inc, HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcats) 0.507 61 >75% Grass cover, Good, HSG B (P1,P1- P10,P11,P1a,P1b) 0.210 98 Paved parking & roofs (P1,P11,P1 b) 2.352 98 Paved roads w /curbs & sewers (P1 -P10) 3.069 Page 2 2/1 3/2007 Zintl Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC Subcatchment P1: to Swale Subcatchment PI -P10: Subcatchment P11: Subcatchment Pia: Subcatchment P'1 b: Reach 2R: Swale Pond Pond 1: 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 Type 1124 - hr 1.5 - Year Rainfa11 =2.54" Page 3 2/1 3/2007 Runoff Area =10,146 sf Runoff Depths 1.22" Tc =3.0 min CN =86 Runoff =0.59 cfs 0.024 af Runoff Area =112,143 sf Runoff Depths 1.93" Flow Length =822' Tc =11.6 min CN =95 Runoff =7.20 cfs 0.414 of Runoff Area =5,934 sf Runoff Depth >0.68" Flow Length =170' Slope= 0.0235 '1' Tc =1.2 min CN=76 Runoff =0.20 cfs 0.008 af Runoff Area=4,697 sf Runoff Depth >0.19" Flow Length =50' Slope= 0.1000 '1' Tc =0.4 min CN =61 Runoff =0.03 cfs 0.002 af Runoff Area =784 sf Runoff Depth >0.24" Flow Length =10' Slope= 0.3000 '1' Tc=0.6 min CN =63 Runoff =0.01 cfs 0.000 of Avg. Depth =0.30' Max Vet =0.53 fps Inflow=0.59 cfs 0.024 af n =0.150 L= 212.0' S= 0.0283 '1' Capacity =1.87 cfs Outflow =0.44 cfs 0.023 af Peak EIev= 939.05' Storage =1,042 cf Inflow=7.25 cfs 0.422 af Outflow =6.89 cfs 0.420 af Total Runoff Area = 3.069 ac Runoff Volume = 0.448 af Average Runoff Depth = 1.75" 16.53% Pervious Area = 0.507 ac 83.47% Impervious Area = 2.562 ac Zintl Proposed 2 -13 -07 Prepared by Falz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.59 cfs a@ 11.94 hrs, Volume= Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 11 24 -hr 1.5 -Year Rainfall=2.60" Area (sf) ON Description 6,800 98 Paved parking & roofs 3,346 61 >75% Grass cover, Good, HSG B 10,146 86 Weighted Average 3,346 Pervious Area 6,800 impervious Area Tc Length Slope Velocity Capacity Description min} (feet} (ft /ft} (ft/sec } (cfs} 3.0 Direct Entry, ❑.65 -- 0.6- 0.55= ❑.5-- 0.45-- ❑.25 -� 0.2- 0.15.- 0.1-- 0.05 -- 10 Subcatchment P1: to Swale Subcatchment P1: to Swale 11 Hydrograph 0.59 cfs 4.024 af, Depths 1.22" 12 13 14 Time (hours) 15 16 Type 11 24-hr 1.5 -Year Rainfall =2.60 ' Page 4 2/1 3/2007 iii ii raiiii Type 1124-hr 1.5 -Year Rainfall= 2.60" RunoffArea=1O,146 sf Runoff VoIumeOM24 of Runoff Depth>t2T' Tc3O min CN =86 17 18 19 20 Zintl Proposed 2- 13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCADQ 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description min} (feet} (ft/ft) [ft /sec) (cfs� Subcatchment P1-P10: Runoff = 7.20 cfs a@ 12.03 hrs, Volume= 0.414 af, Depth> 1.93" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type 1124-hr 1.5 -Year Rainfall =2.60" Area (sf) CN Description 9,705 61 >75% Grass cover, Good, HSG B 102,438 98 Paved roads w /curbs & sewers 112,143 95 Weighted Average 9,705 Pervious Area 102,438 impervious Area 6.1 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 2.75" 2.5 150 0.0200 0.99 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 0.7 90 0.0110 2.13 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 90 0.0147 2.46 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.1 256 0.0050 4.03 4.95 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.012 Concrete pipe, finished 0.5 164 0.0050 5.05 12.14 Circular Channel (pipe), Diam= 21.0" Area= 2.4 sf Perim= 5.5' r= 0.44' n= 0.012 Concrete pipe, finished 0.1 22 0.0050 5.52 17.33 Circular Channel (pipe), Diam= 24.0" Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Concrete pipe, finished 11.6 822 Total Type 11 24 1.5 - Year Rainfal1=2.66" Page 5 2/13/2007 Zintl Proposed 2-13-07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 062112 © 2006 HydroCAD Software Solutions LLC U 0 1 10 Subcatchment P1-P10: 11 Hydrograph 7.20 cfs 12 13 14 Time (hours) 15 16 Type 1124 -hr 1.5 -Year Rainfall = 2.60" Page 6 2/1 3/2007 zeimear Aedv-4~,eof Type 1124-hr 1.5 -Year Rai nfaII26O't RunoffArea=112,143 sf Runoff VoIumeO.414 of Runoff Depth >1.93" Flow Length =822' Tc1t6 min CN =95 17 18 19 20 D Runoff Zintl Proposed 2 -13047 Prepared by FoIz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.20 cfs a@ 11.91 hrs, Volume= Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 11 24 -hr 1.5 -Year Rainfall =2.60" 0.22= 0.21 0.2 =: 0.191 0.18 0.17- 0.16- 0.15-4 0.14... 0.11 LL 0.1 0.09- 0.08= 0.07, 0.05 0.04= 0.03 - 0.02 0.01 Area (sf} CN Description 3,598 61 >75% Grass cover, Good, HSG B 2,336 98 Paved parking & roofs 5,934 76 Weighted Average 3,598 Pervious Area 2,336 Impervious Area Tc Length Slope Velocity Capacity Description min} (feet} (ft /ft] (ft /sec] (cfs] 1.2 170 0.0235 2.30 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 5 10 11 Subcatchment P11: Subcatchment P11: Hydrograph 0.20 cfs 0.008 af, Depth> 0.68" 12 13 14 Time (hours) Type 1124-hr 1.5 -Year Rai nfaI1=26O" Runoff Area5,934 sf Runoff VoIumeO.008 af Runoff Depth>O68" Flow L Slope0M235 '1' Tc=t2 min CN =76 15 16 Type 11 24-hr 1.5 -Year Rainfall =2.60" Page 7 2/13/2007 17 18 19 20 0 Runoff Zintl Proposed 2-13-07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc <2dt may require smaller dt Runoff - 0.03 cfs a@ 11.94 hrs, Volume= Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type II 24 -hr 1.5 -Year Rainfall =2.60" Area (sf) CN Description 4,697 61 >75% Grass cover, Good, HSG B 4,697 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft /ft) (ft /sec) (cfs) 0.4 50 0.1000 2.11 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.75" v 0 0 0.032 0.03 0.028_: 0.026 - 0.024H 0.022 0.02= 0.018H 0.016 0.014 0.012•^ 0.01-= 0.0087. 0.006 0.004 0.002-= 0- 0.03 cfs 10 11 Subcatchment Pia: Hydrograph 0.002 af, Depths 0.19" Subcatchment Pia: 12 13 14 Time (hours) Type 11 24-hr 1.5 -Year Rainfal1=2.60" Page 8 2/1 3/2007 Type 1124-hr 1.5 -Year Rai nfaH=26O" Runoff Area =4,697 sf Runoff Volume=O.002 of Runoff Depth>0A9" Flow Length =50' S1ope=O1OOO '/' Tc0.4 min CN =61 15 16 17 18 19 20 0 Runoff Zinti Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.01 cfs © 11.93 hrs, Volume= 0.000 af, Depths 0.24" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type II 24 -hr 1.5 -Year Rainfall= 2.60" Area s CN Description 751 61 33 98 Paved parking & roofs Tc Length >75% Grass cover, Good, HSG B 784 63 Weighted Average 751 Pervious Area 33 Impervious Area Slope Velocity Capacity min feet ftlft ft /sec cfs 0.6 0.008 -_ o. 008 0.007- 0.0062 0.006 -- 0.005H 0.005-= - 0.004 0.004 : o. 0.003 - 0,003- 0.002-: 0.002 =: 0.001 0.001 -= 0, 000 0: 10 0.3000 Subcatchment Pl b: Description 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.75" Subcatchment PIb: Hydrograph z 0.01 cfs 10 11 12 13 14 Time (hours) Type 1124 -hr 1.5 -Year Rainfall =2.60" Page 9 2/13/2007 Type 1124-hr 1.5 -Year RainfaII=2.60" Runoff Area =784 sf Runoff VoIumeO.000 af Runoff Depth>O24" Flow Length=1O' SIopeO3OOO '1' TcO6 min CN =63 15 16 17 18 19 20 Zintl Proposed 2-13-07 Prepared by FoIz, Freeman, Erickson, Inc. HydroCAD® 8.66 sln 002112 © 2666 HydroCAD Software Solutions LLC Inflow Area = 0.233 ac, Inflow Depth > 1.22" for 1.5 -Year event Inflow = 0.59 cfs a@ 11.94 hrs, Volume= 0.024 of Outflow = 0.44 cfs © 12.10 hrs, Volume= 0.023 af, Atten= 27 %, Lag= 9.6 min Routing by Stor -Ind +Trans method, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 0.53 fps, Min. Travel Time= 6.7 min Avg. Velocity = 0.19 fps, Avg. Travel Time 18.3 min Peak Storage= 178 cf © 11.99 hrs, Average Depth at Peak Storage= 0.30' Bank -Full Depth= 0.56', Capacity at Bank -Full= 1.87 cfs 1.00' x 0.56' deep channel, n= 0.150 Sheet flow over Short Grass Side Slope Z- value= 6.0 Top Width= 7.72' Length= 212.0' Slope= 0.0283 '1' Inlet Invert= 54.00', Outlet Invert= 48.00' 0.65 -: 0.55-- 0.5- 0.45 - 0.4- 0,35- 2 u. 0.3- 0.25 --- 0.2- 0.15- 0.1-: 0.05 -- 0--- Reach 2R: Swale Reach 2R: Swale Hydrograph 0.59 cfs r 9.44 cfs ./' 401W41 , . a p , .. ; ftffifOr#552i7eireZeMWZAW 10 11 12 13 14 Time (hours) 15 16 Type 1124 -hr 1.5 -Year Rainfall =2.60" Page 10 2/13/2007 nflow AreaO233 ac Avg. D Max VeI=O53 fps n =0.150 L= 212.0' S= 0.0283 '/' Capacity=L87 cfs 17 18 19 20 ® Inflow 0 Outflow Zintl Proposed 243 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [82] Warning: Early inflow requires earlier time span Inflow Area = Inflow -- Outflow = Primary = Elevation (feet) 938.00 939.00 939.50 2.711 ac, Inflow Depth > 1.87" for 1.5 -Year event 7.25 cfs a@ 12.03 hrs, Volume= 6.89 cfs @ 12.06 hrs, Volume= 6.89 cfs a@ 12.06 hrs, Volume= Routing by Stor -Ind method, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Peak EIev= 939.05' © 12.06 hrs Surf.Area= 1,519 sf Storage= 1,042 cf Plug --Flow detention time= 5.5 min calculated for 0.420 af (100% of inflow) Center -of -Mass det. time= 3.8 min ( 760.7 - 756.9 ) Volume Invert Avail.Storage Storage Description #1 938.00' 1,812 cf Custom Stage Data (Irregular)Listed below (Recalc) Surf.Area (sq - ft) 539 1,484 1,880 Device Routine Invert #1 Primary 938.00' #2 Primary 938.00' Perim. (feet) 123.0 259.0 268.0 Pond Pond 1: Inc.Store Cum.Store (cubic -feet) (cubic -feet) 0 0 972 972 839 1,812 Outlet Devices 18.0" x 46.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.80' S= 0.0043 '1' Cc= 0.900 n= 0.012 Concrete pipe, finished 18.0" x 46M' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.80' S= 0.0043 '1' Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max =6.82 cfs © 12.06 hrs HW= 939.04' (Free Discharge) -1 =Culvert (Barrel Controls 3.41 cfs J 3.67 fps) -2 =Culvert (Barrel Controls 3.41 cfs © 3.67 fps) 0 0 0 Pond Pond 1: Hydrograph 7.25 cfs 6.89 cfs 10 11 12 13 14 Time (hours) 0.422 af 0.420 af, Atten= 5 %, Lag= 1.9 min 0.420 af 15 16 Type 1124 -fir 1.5 -Year Rainfall= 2.64" Page 11 2/13/2007 Wet.Area (sq - ft) 539 4,678 5,077 nflow Area=211 1 ac Peak EIev939M5' Storage1,042 cf gram 17 18 19 20 El Inflow 0 Primary Zi nti Proposed 2 -13-07 Prepared by FoIz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC Subcatchment P1 : to Swale Subcatchment P1 -P10: Subcatchment P11: Subcatchment Pia: Subcatchment Pi b: Reach 2R: Swale Pond Pond 1: 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 Type 11 24 74 - Year Rainfall= 4.20" Page 12 2/13/2007 Runoff Area =10,146 sf Runoff Depth >2.54" Tc =3.0 min CN =86 Runoff=1.19 cfs 0.049 of Runoff Area= 112,143 sf Runoff Depth >3,39" Flow Length =822' Tc =11.6 min CN =95 Runoff =12.26 cfs 0.727 of Runoff Area =5,934 sf Runoff Depth >1.74" Flow Length =170' Slope =0.0235 7' Tc =1.2 min CN =76 Runoff =0.51 cfs 0.020 af Runoff Area =4,697 sf Runoff Depth >0.81" Flow Length =50' Slope =0.1000 7' Tc =0.4 min CN=61 Runoff =0.19 cfs 0.007 of Runoff Area =784 sf Runoff Depth >0.92" Flow Length =10' Slope= 9.3000 7' Tc =0.6 min CN =63 Runoff =0.04 cfs 0.001 af Avg. Depth =0.42' Max Vet =0.64 fps Inflow =1.19 cfs 0.049 af n =0.150 L =212.0' S=0.0283 '1' Capacity=1.87 cfs Outflow =0.93 cfs 0.049 of Peak EIev =939.47' Storage =1,748 cf Inflow =12.32 cfs 0.747 af Outflow =11.68 cfs 0.745 af Total Runoff Area m 3.069 ac Runoff Volume = 0.805 af Average Runoff Depth = 3.15" 16.53% Pervious Area = 0.507 ac 83.47% Impervious Area = 2.562 ac Zintl Proposed 2 - - Type II 24 -hr 14 -Year Rainfall =4.20' Prepared by Folz, Freeman, Erickson, Inc. Page 13 HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions [LC 2/13/2007 [49] Hint: Tc<2dt may require smaller dt Runoff -- 1.19 cfs a@ 11.93 hrs, Volume= Tc Length min feet - v 0 0 3.0 Area (sf) CN Description 6,800 98 Paved parking & roofs 3,346 61 >75% Grass cover, Good, HSG B 10,146 86 Weighted Average 3,346 Pervious Area 6,800 Impervious Area 10 Subcatchment P1: to Swale Runoff by SCS TR -20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type I124-hr 10 -Year Rainfall =4.20" Slope Velocity Capacity Description ft /ft ft/sec cfs Direct Entry, Subcatchment P1: to Swale 11 Hydrograph 1 19 cfs ,nommr/zoPir 46#40,Wfxfw 0.049 af, Depth> 2.54" Type 1124-hr 10 -Year Rai nfall=4.20" RunoffArea=1O,146 sf Runoff Volume=O.049 af Runoff Depth>254" Tc3O min CN =86 12 13 14 Time (hours) 15 16 17 18 19 20 0 Runoff Zintl Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC Subcatchment P1 -P10: Runoff = 12.26 cfs © 12.03 hrs, Volume= 0.727 at Depths 3.39" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type ll 24-hr 10 -Year Rainfall= 4.20" Area (sf} CN Description 9,705 61 >75% Grass cover, Good, HSG B 102,438 98 Paved roads w /curbs & sewers 112,143 95 Vveighted Average 9,705 Pervious Area 102,438 Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (ft /sec) (cfs) 6.1 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 2.75" 2.5 150 0.0200 0.99 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 0.7 90 0.0110 2.13 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 90 0.0147 2.46 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.1 256 0.0050 4.03 4.95 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.012 Concrete pipe, finished 0.5 164 0.0050 5.05 12.14 Circular Channel (pipe), Diam= 21.0" Area= 2.4 sf Perim= 5.5' r= 0.44' n= 0.012 Concrete pipe, finished 0.1 22 0.0050 5.52 17.33 Circular Channel (pipe), Diam= 24.0" Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Concrete pipe, finished 11.6 822 Total Type 11 24 10 - Year Rainfall =4.20" Page 14 2/13/2007 Zintl Proposed 2-13-07 Prepared by Foiz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC 13- 12- 11- 10- 9-- 5- 4w 3 2-- -eeeeeee/ZeA 10 11 Subcatchment P1 -P10: Hydrograph 12.26 cis 12 13 14 Time (hours) Type 11 24hr 10 -Year RainfaII4.20" Runoff Area112,143 sf Runoff Voume=OJ27 of Runoff Depth>339" FIow Length =822' Tc1t6 min CN =95 15 16 Type 11 24-hr 10 -Year Rainfall =4.20" Page 15 2/1 3/2007 17 18 19 20 0 Runoff Zintl Proposed 2-13-07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8,00 sin 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.51 cfs a© 11.91 hrs, Volume= Runoff by SCS TR -20 method, UH =SCS, Time Span= 5,00 -20.00 hrs, dt= 0.05 hrs Type 11 24 -hr 10 -Year Rainfall =4.20" Tc Length min feet ft /ft ft /sec cfs 1.2 0.55 - 0,5- 0.45 0.4 -- 0,35- - N U 0.3-- it 0.25- Area (sf) CN Description 3,598 61 >75% Grass cover, Good, HSG B 2,336 98 Paved parking & roofs 5,934 76 Weighted Average 3,598 Pervious Area 2,336 Impervious Area 0.2-- 0.15 -- 0.1 -. 0.05 -- 170 0.0235 zezmeezzoo 6 Slope Velocity Capacity 2.30 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps 10 Description 11 Subcatchment P11: Subcatchment P11: Hydrograph 0.51 cfs 0.024 af, Depths 1.74" 12 13 14 Time (hours) 15 16 Type 11 24-hr 1O --Year Rainfall= 4.20" Page 16 2/1 3/2007 Type 1124-hr 10 -Year RainfaU=42O" Runoff Area5,934 sf Runoff Volume=0M20 of Runoff Depth>1 74' Flow Lengthl7O' Slope=0M235 '1' Tct2 min CN =76 17 18 19 20 Zinti Proposed 2-13-07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.19 cfs ©a 11.91 hrs, Volume= Area (sf) CN Description 4,697 61 >75% Grass cover, Good, HSG B 4,697 Pervious Area 9.21•: 0.2r 0.19- 0.18- 0.17-: 0.16:= 0.15". 0.14 -ry 9.13 0.12 0.11 0.1' 0.08, 9.07 -. O.06 0.05- 0.04 - 0. 03- 0, 02- (101". 0- 5 10 11 Subcatchment Pia: 0.007 af, Depths 0.81" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 11 24-hr 10-Year Rainfall =4.20" To Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft /sec) (cfs) 0.4 50 0.1000 2.11 Sheet Flow, Smooth surfaces n= 0.011 P2= 2.75" Subcatchment Pia: Hydrograph 0.19 cfs 12 13 14 Time (hours) 15 16 Type 11 24-hr 10 -Year Rainfall =4.20" Page 17 2/1 3/2007 Type 1124-hr 10 -Year Rai nfaII=42O" Runoff Area =4,697 sf Runoff Voume=OMO7 of Runoff Depth>OE81" Flow Length5O' SIope=O1OOO '/' TcO4 min CN =61 17 18 19 20 0 Runoff Zintl Proposed 2-13417 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.04 cfs © 11.91 hrs, Volume= 0.001 af, Depths 0.92" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type I124-hr 10 -Year Rainfall =4.20" Area (sf) CN Description 751 61 >75% Grass cover, Good, HSG B 33 98 Paved parking & roofs 784 63 Weighted Average 751 Pervious Area 33 Impervious Area Tc Length min feet ft /ft ft /sec cfs 0 L 0.6 0.04- 0.038- 0.338 0.034- 0.032 0.03 0.028 -= 0.026 0.024- 0.022 0.02 0.018 -- 0.016-- 0.014= 0.012: 0.01 0.008: 0.006 0.002 0- 5 10 0.3000 Slope Velocity Capacity Description Subcatchment Pi b: 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.75" Subcatchment Pi b: Hydrograph 4.04 cfs 9 10 11 12 13 14 Time (hours) 15 16 Type 11 24-hr 1O -Year Rainfall =4.20" Page 18 2/13/2007 4 Type 11 24hr 10 -Year RainfaII42O" Runoff Area784 sf Runoff VoIumeOMOl af Runoff D Flow L SIopeO3OOO '/' Tc0.6 min CN =63 17 18 19 20 CD Runoff Zintl Proposed 2 -13 -07 Prepared by FoIz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 602112 © 2006 HydroCAD Software Solutions LLC Inflow Area = 0.233 ac, Inflow Depth > 2.54" for 10 -Year event Inflow = 1.19 cfs @ 11.93 hrs, Volume= 0.049 af Outflow = 0.93 cfs a@ 12.07 hrs, Volume= 0.049 af, Atten= 22 %, Lag= 8.1 min Routing by Stor- Ind +Trans method, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 0.64 fps, Min. Travel Time= 5.5 min Avg. Velocity = 0.22 fps, Avg. Travel Time 15.9 min Peak Storage= 312 cf a@ 11.98 hrs, Average Depth at Peak Storage= 0.42' Bank -Full Depth= 0.56', Capacity at Bank -Full= 1.87 cfs 1.00' x 0.56' deep channel, n= 0.150 Sheet flow over Short Grass Side Slope Z- value= 6.0 '1' Top Width= 7.72' Length= 212.0' Slope= 0.0283 '1' Inlet Invert= 54.00', Outlet Invert= 48.00' Reach 2R: Swale • Reach 2R: Swale Hydrograph 1.19 cfs 0.93 cfs nflow Area=O233 ac Avg. DepthO42' Max VeIO64 fps n =0.150 L= 212.0' S =0.0283 '1' Capacty1.87 cfs 10 11 12 13 14 Time (hours) 15 16 17 Type II 24 -hr 1O -Year Rainfall =4.24" Page 19 2/1 3/2007 18 19 20 Inflow 0 Outflow Zintl Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [82] Warning: Early inflow requires earlier time span Inflow Area = 2.711 ac, Inflow Depth > 3.31" for 10 -Year event Inflow = 12.32 cfs @ 12.02 hrs, Volume= 0.747 of Outflow = 11.68 cfs @ 12.06 hrs, Volume= 0.745 af, Atten= 5 %, Lag= 2.1 min Primary = 11.68 cfs @ 12.06 hrs, Volume= 0.745 af Routing by Stor -Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 939.47' @ 1 2.06 hrs Surf.Area= 1,852 sf Storage= 1,748 cf Plug -Flow detention time= 4.6 min calculated for 0.742 af (99% of inflow) Center -of -Mass det. time 3.3 min ( 750.5 - 747.2 ) Volume Invert Avail.Storage Storage Description #1 938.00' 1,812 cf Custom Stage Data (Irregular)Listed below (Recalc) Elevation feet 938.00 939.00 939.50 Device Routin #1 #2 Primary 13- 12- 5- 4- 3-- 2.- Primary Surf.Area Perim. s• -ft feet 539 123.0 1,484 259.0 1,880 268.0 Pond Pond 1: Inc.Store Cum.Store cubic -feet cubic -feet 0 0 972 972 839 1,812 Type 11 24 10 Rainfall =4.24" Page 20 2/1 3/2007 Wet.Area s• -ft 539 4,678 5,077 Invert Outlet Devices 938.00' 18.0" x 46.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.80' S= 0.0043 '1' Cc= 0.900 n= 0.012 Concrete pipe, finished 938.00' 18.0" x 46.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.80' S= 0.0043 '1' Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max =11.56 cfs @ 12.06 hrs HW =939.46' (Free Discharge) -1= Culvert (Barrel Controls 5.78 cfs J 4.20 fps) -2=Culvert (Barrel Controls 5.78 cfs a@7 4.20 fps) Pond Pond 1: Hydrograph 12,32 cfs 11.68 cfs nflow Area2M7l 1 ac Peak E1ev939.47' Storagel ,748 cf "PAirgi 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 1 Inflow 0 Primary ZintI Proposed 2-13-07 Prepared by Folz, Freeman, Erickson, Inc. HvdroCADO 8.00 s/n 002112 © 2006 HvdroCAD Software Solutions LLC Subcatchment P1: to Swale Subcatchment P1 -P10: Subcatchment P11: Subcatchment Pia: Subcatchment P1 b: Reach 2R: Swale Pond Pond 1: 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 Type 1124 - hr 100 - Year Rainfa11 =5.99" Page 21 2/13/2007 Runoff Area = 10,146 sf Runoff Depth >4.04" Tc =3.0 min CN =86 Runoff =1.82 cfs 0.078 of Runoff Area = 112,143 sf Runoff Depth >4.94" Flow Length= 822' Tc =11.6 min CN=95 Runoff =17.56 cfs 1.060 of Runoff Area =5,934 sf Runoff Depth >3.05" Flow Length =170' Slope=0.0235 '1' Tc =1.2 min CN =76 Runoff =0.88 cfs 0.035 af Runoff Area =4,697 sf Runoff Depths 1.75" Flow Length =50' Slope = 0.1000 '1' Tc =0.4 min CN =61 Runoff =0.43 cfs 0.016 af Runoff Area =784 sf Runoff Depths 1.91" Flow Length =10' Slope= 0.3000'1' Tc =0.6 min CN =63 Runoff =0.08 cfs 0.003 of Avg. Depth =0.51' Max VeI =0.72 fps Inflow =1.82 cfs 0.078 af n =0.150 L= 212.0' 5=0.0283 Capacity =1.87 cfs Outflow =1.46 cfs 0.078 of Peak Elev= 940.39' Storage =1,812 cf Inflow =17.68 cfs 1.094 af Outflow =19.89 cfs 1.092 af Total Runoff Area = 3.069 ac Runoff Volume = 1.192 af Average Runoff Depth = 4.66" 16.53% Pervious Area = 0.507 ac 83.47% Impervious Area = 2.562 ac Zlntl Proposed 2 - - Type 1124 -hr 100 -Year Rainfall= 5.90" Prepared by Folz, Freeman, Erickson, Inc. Page 22 HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC 2/1 3/2007 [49) Hint: Tc<2dt may require smaller dt Runoff -- 1.82 cfs @ 11.93 hrs, Volume= Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type 1I24-hr 100 -Year Rainfall= 5.90" 0 LL Area (sf) CN 6,800 98 3,346 61 10,146 3,346 6,800 Description Paved parking & roofs >75% Grass cover, Good, HSG B 86 Weighted Average Pervious Area Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft /ft) (ft /sec) cfs) 3.0 40:01.007.007,10 .~.4/7 10 Subcatchment P1: to Swale Direct Entry, Subcatchment P1: to Swale 11 Hydrograph 1.82 cfs 0.078 af, Depth> 4.04" 12 13 14 Time (hours) Type 1124-hr 100 -Year RainfaII59O" Runoff ArealO,146 sf Runoff Vo1umeOO78 af Runoff Depth >4.04" Tc=&O min CN =86 15 16 17 18 19 20 0 Runoff Zintl Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description min (feet] (ft/ft ft/sec cfs} Subcatchment P'1 -P10: Runoff = 17.56 cfs a[7 12.03 hrs, Volume= 1.060 af, Depths 4.94" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -Year Rainfall =5.90" Area (sf) CN Description 9,705 61 >75% Grass cover, Good, HSG B 102,438 98 Paved roads w /curbs & sewers 11 2,143 95 Weighted Average 9,705 Pervious Area 102,438 Impervious Area 6.1 50 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 2.75" 2.5 150 0.0200 0.99 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps 0.7 90 0.0110 2.13 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 90 0.0147 2.46 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.1 256 0.0050 4.03 4.95 Circular Channel (pipe), Diam= 15.0" Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.012 Concrete pipe, finished 0.5 164 0.0050 5.05 12.14 Circular Channel (pipe), Diam =21.0" Area =2.4sf Perim =5.5' r=0.44' n= 0.012 Concrete pipe, finished 0.1 22 0.0050 5.52 17.33 Circular Channel (pipe), Diam= 24,0" Area= 3.1 sf Perim= 6.3' r= 0.50' n= 0.012 Concrete pipe, finished 11.6 822 Total Type 1124 - hr 100 - Year Rainfall=5.90" Page 23 2/1 3/2007 Zint1 Proposed 2 -13 -07 Type 1124 -hr 100-Year Rainfall =5.94" Prepared by Fofz, Freeman, Erickson, Inc. Page 24 H droCAD® 8.00 s/n 002112 © 2006 H droCAD Software Solutions LLC 2/13/2007 19 18 17 16 15 =: 14 13 12' 11_ 10 9.w 8 7 5 M: 3 10 11 Subcatchment P1 -P10: Hydrograph 17.56 cfs z‘we,z, 4 12rar ee 12 13 14 Time (hours) Type II 24 -hr 100 -Year Rai nfaU=59O" Runoff Areall2,143 sf Runoff VoPumel O6O of Runoff Depth>494" Flow Length =822' Tc=1t6 min CN =95 15 16 17 18 19 20 p Runoff Zi ntl Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. Hyd roCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff = 0.88 cfs © 11.91 hrs, Volume= 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 sf CN Description 3,598 61 >75% Grass cover, Good, HSG B 2,336 98 Paved parkin. & roofs 5,934 3,598 2,336 Tc Length min feet ft /ft ft /sec cfs 0 L 1.2 0.95 0.9. 0.85 0.8. 0.75 0.7 Y 0.55•= 0.4' 0.35- 0.3w. 0.25 0.2- 0.15, 0.1- 0.05- 0 = 170 0.0235 76 Weighted Average Pervious Area Impervious Area Slope Velocity Capacity Subcatchment P11: Description 2.30 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps Subcatchment P11: Hydrograph 0.88 cfs 0.035 af, Depth> 3.05" Type 11 24 100 - Year Rainfall =5.90" Page 25 2/1 3/2007 zwmierdzehrierxeowerao 01'4~ OfWeleMdWiret edre/FAV Type II 24 -hr 100 -Year RainfaII59O" Runoff Area5,934 sf Runoff Volume=0M35 of Runoff Depth>3M5" Flow L SIopeOM235 Tc=1.2 min CN =76 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 D Runoff Zintl Proposed 2 -13-07 Prepared by FoIz, Freeman, Erickson, Inc. H droCAD® 8.00 s/n 002112 © 2006 H droCAD Software Solutions LLC [49] Hint: Tc<2dt may require smaller dt Runoff -- 0.43 cfs © 11.90 hrs, Volume= 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" Tc Length Slope Velocity Capacity Description min feet ft /ft ft /sec [cfs} 0.4 50 0.1000 2.11 Areas CN Descri tion 0.46= 0,42 0.4= 0.38 0.36` 0.34: 0.32 0,3 0.28.: 0.26 0.24 0.22^ 0.2 0.18. 0.16 - 0.14 0.12; 0.1- o. a8 == 0.06 0.021 0 -= 5 4,697 61 >75% Grass cover, Good, HSG B 4,697 Pervious Area Sheet Flow, Smooth surfaces n= 0.011 P2= 2.75" Type 1124-hr 100 -Year RainfaII59O" Runoff Area4,697 sf RunoffVoIumeOO16 of Runoff Depth>1J5" Flow Length5O' SIopeOA000 '1' TcO4 min CN =61 .14 0.43 cfs 6 7 8 9 10 11 Subcatchment Pia: Hydrograph 0.016 at Depths 1.75" Subcatchment Pia: 12 13 14 Time (hours) 15 16 Type 1124 -hr 100 -Year Rainfall= 5.94►' Page 26 2/13/2007 17 18 19 20 0 Runoff Zintl Proposed 2 - - Type 1124 -hr 100 -Year Rainfall =5.9O" Prepared by Folz, Freeman, Erickson, Inc. Page 27 HydroCADQ 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC 2/1 3/2007 [49] Hint: Tc <2dt may require smaller dt Runoff = 0.08 cfs a@ 11.90 hrs, Volume= U) 0 Tc Length min feet ft/ft ft /sec cfs 0.6 Area (sf) CN Description 751 61 >75% Grass cover, Good, HSG B 33 98 Paved parking & roofs 784 63 Weighted Average 751 Pervious Area 33 Impervious Area 0.085 0.08H. 0.075- 0.07 0.065- 0.06- 0.055- 0.05-: 0.045- 0,04-: 0.035- 0.03 0.025._ 0.02 0.015- - 0.01 -= 0.005- 0 -- 10 0.3000 Slope Velocity Capacity 10 11 Subcatchment Pib: 0.003 af, Depths 1.91" Runoff by SCS TR -20 method, UH =SCS, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Type II 24 -hr 100 -Year Rainfall= 5,90" Description 0.29 Sheet Flow, Grass: Short n= 0.150 P2= 2.75" Subcatchment P'1 b: Hydrograph 0.08 cfs few 12 13 14 Time (hours) Type 11 24hr 100 -Year Rainfa1I59O" Runoff Area784 sf Runoff Volume=O.003 of Runoff Depth>t91" Flow Length=1O' SIopeO3OOO '1' Tc0.6 min CN =63 15 16 17 18 19 20 0 Runoff Zintl Proposed 2 -13 -07 Prepared by Folz, Freeman, Erickson, Inc. HydroCADO 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC Reach 2R: Swale Inflow Area = 0.233 ac, Inflow Depth > 4.04" for 100 -Year event Inflow = 1.82 cfs a@ 11.93 hrs, Volume= 0.078 of Outflow = 1.46 cfs © 12.05 hrs, Volume= 0.078 af, Atten= 20 %, Lag= 7.2 min Routing by Stor- Ind +Trans method, Time Span= 5.00 -20,00 hrs, dt= 0.05 hrs Max. Velocity= 0.72 fps, Min. Travel Time= 4.9 min Avg. Velocity = 0.25 fps, Avg. Travel Time 14.0 min Peak Storage= 439 cf a@ 11.97 hrs, Average Depth at Peak Storage= 0.51' Bank -Full Depth= 0.56', Capacity at Bank -Full= 1.87 cfs 1.00' x 0.56' deep channel, n= 0.150 Sheet flow over Short Grass Side Slope Z- value= 6.0 '1' Top Width= 7.72' Length= 212.0' Slope= 0.0283 '1' Inlet Invert= 54.00', Outlet Invert= 48.00' o LI Reach 2R: Swale Hydrograph Type 1124 - hr 100 - Year Rainfall =5.90" Page 28 2/1 3/2007 1.82 cfs 10 11 12 13 14 Time (hours) nflow AreaO.233 ac Avg. DepthO51' Max Ve1O72 fps n =0.150 L= 212.0' S= 0.0283 '/' Capacityt87 cfs 15 16 17 18 19 20 0 Inflow 0 Outflow Zintl Proposed 2 -13 -07 Prepared by FoIz, Freeman, Erickson, Inc. HydroCAD® 8.00 sin 002112 © 2006 HydroCAD Software Solutions LLC [82] Warning: Early inflow requires earlier time span [931 Warning: Storage range exceeded by 0.89' [88] Warning: Qout >Qin may require Finer Routing >1 Pond Pond 1: inflow Area = 2.711 ac, Inflow Depth > 4.85" for 100 -Year event Inflow = 17.68 cfs a© 12.02 hrs, Volume= 1.094 of Outflow = 19.89 cfs 12.00 hrs, Volume= 1.092 af, Atten= 0 %, Lag= 0.0 min Primary = 19.89 cfs a@ 12.00 hrs, Volume = 1.092 of Routing by Stor -Ind method, Time Span= 5.00 -20.00 hrs, dt= 0.05 hrs Peak Elev= 940.39' © 12.00 hrs Surf.Area = 1,880 sf Storage = 1,812 cf Plug -Flow detention time= 4.0 min calculated for 1.088 af (99% of inflow) Center -of -Mass det. time 2.8 min ( 745.0 - 742.1 ) Volume Invert Avail.Storage Storage Description #1 938.00' 1,812 cf Custom Stage Data tlrregular)Listed below (Recalc) Elevation Surf.Area Perim. lnc.Store Cum.Store Wet.Area feet s• -ft feet cubic -feet cubic -feet s• -ft 938.00 539 123.0 0 0 539 939.00 1,484 259.0 972 972 4,678 939.50 1,880 268.0 839 1,812 5,077 Device Routine #1 Primary #2 Primary Invert Outlet Devices 938.00' 18.0" x 46.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.80' S= 0.0043'1' Cc= 0.900 n= 0.012 Concrete pipe, finished 938.00' 18.0" x 46.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 937.80' S= 0.0043 Cc= 0.900 n= 0.012 Concrete pipe, finished Primary OutFlow Max =19.27 cfs @ 12.00 hrs HW= 940.32' (Free Discharge) '1= Culvert (Barrel Controls 9.63 cfs a@ 5.45 fps) 2= Culvert (Barrel Controls 9.63 cfs a@ 5.45 fps) Type 11 24 100 - Year Rainfall =5.90" Page 29 2/13/2007 Zintl Proposed 2 -13-07 Prepared by Folz, Freeman, Erickson, Inc. HydroCAD® 8.00 s/n 002112 © 2006 HydroCAD Software Solutions LLC 0 22- 21_ 20 =. 19-- 18 -= 17 16-- 15 14- 13 12 11 1 o-. 8-� 7-E 5- 3- 2-- Pond Pond 1: Hydrograph Type 1124 - hr 100 - Year Rainfall= 5.90" Page 30 2/1 3/2007 dreiff0WV2WA:4,nr `- -FxrEmek-40- 444zezeozed a 19.89 cfs nflow Area271 1 ac Peak EIev94O39' Storagel,812 cf cfs 10 11 12 13 14 Time (hours) 15 16 17 18 19 20 El Inflow 0 Primary MEMORANDUM Date: February 7, 2007 To: BCWD Board of Managers; Karen Kill, Administrator From: Lisa Tilman, P.E. and Camilla Correll, P.E. Re: Permit No. 06-30 — W.A.T.E. Office Warehouse, Oak Park Heights, MN GENERAL COMMENTS Ecjit EMMONS & OLIVIER RESOURCES The following review of the above mentioned project located within the legal jurisdiction of the Brown's Creek Watershed District (BCWD) was conducted to determine compliance with the BCWD rules pursuant to the Board's permit issuance determination for this project. The proposed development project includes two office warehouse buildings and associated parking on a 2.6-acre lot. The majority of the site is located within the Kern Center Pond drainage area. The applicant has indicated that this parcel is the final portion for development under a PUD that includes a total of 15.5 acres within the Kern Center Plat The site is currently vacant and contains no impervious surfaces. Under existing conditions, 86% of the site drains to the Kern Center Pond and 14% of the site drains to a wetland located at the northwest corner of the property. The proposed site will be 85% impervious. Under proposed conditions, 92% of the site drains to the Kern Center Pond and only 8% drains to the wetland in the northwest corner of the lot. All 2.2 acres of impervious surface are intended to be directed to the Kern Center Pond. Drainage from the western storage building is directed toward the Kern Center Pond through a shallow swale that curves around the back of the building (see attached Site Plan). While this swale may be effective in redirecting flow for small events, it is unlikely that the swale will effectively redirect all of the drainage from the storage building to the Kern Center Pond. As modeled by EOR, the swale has the capacity for a 1.5 year event, but does not have capacity for the 1 0-year and 1 00-year events. Therefore, in larger events a portion of the drainage may flow toward the wetland at the northwest corner of the property. To avoid this occurrence the swale should be designed with a larger berm at the north end of the building. Additionally, soils must be provided with permanent stabilization to prevent erosion in this area. The design for the Kern Center Pond allowed for up to 73.6 acres of impervious cover in the full Kern Center Pond drainage area. The original drainage area currently contains about 44.7 acres of impervious surface and 30 acres of undeveloped parcels. About 1.9 acres of additional impervious surface was added to the original drainage area from the Zintl PUD. Making A Difference Through Integrated Resource Management FOR, INC.. 651 Hale Avenue North. Oakdale, MN 55128• Tel: (651) 770-8448• Fax: (651) 770-2552 Page 2 2/7/07 BCJ'VVD Development Review—W.A.TE Office/Warehouse, Oak Park Heights Rule 2.0 STORMWATER MANAGEMENT The report analyzes the proposed project under the following scenarios: 1. .June 2003 policy still in effect If the June 2003 policy is considered to be in effect, the full Kern Center Plat is allowed to develop up to 80% impervious without including any treatment for portions of the site draining untreated away from the Kern Center Pond. If the policy is evaluated on a lot by lot basis, the proposed development exceeds the allowed impervious surface cover and would require additional treatment for the 5% excess impervious surface. The impervious surface coverage of the full PUD is 67% if the open water wetland is included as "green space ". If only the upland portion of the green space is included, the impervious surface coverage of the PUD is almost 80 %. Therefore, if the policy is evaluated over the PUD, the conditions of the policy are met and no additional treatment would be necessary. 2. Kern Center Pond Cooperative Agreement applied to drainage area with drainage to other basins required to meet BCWD standards. Compliance with Cooperative Agreement based on 80% impervious allowed over fill' Kern Center drainage area. This scenario would allow 73.6 acres of impervious cover in the full Kern Center Pond drainage area. The original drainage area currently contains 44.7 acres of impervious surface. An additional 1.9 acres of impervious surface was added from expansion of the original drainage area within the Zintl PUD area. Therefore, the pond has the capacity for an additional 27.0 acres of impervious surface within the drainage area. Under this scenario, the proposed project would use 2.2 of the remaining 27.0 acres, reducing the total allowed future impervious area to 24.8 acres. To further compensate for the increased drainage area to the pond (1.9 acres for the existing Zintl PUD and 0.18 acres for the WATE site), the allowed future hard surface should be reduced to 22.7 acres. No additional treatment would be required in the Kern Center Pond area under this scenario. However, this scenario restricts future development on currently undeveloped parcels. The area of undeveloped parcels within the Kern Center Pond drainage area is 30 acres including 9.3 acres within Lake Elmo. To allow the remaining parcels to develop to the 80% impervious level would require 24.0 acres of the remaining 22.7 acres of impervious surface allowed. This scenario does not allow for all parcels to develop to the 80% level, especially if the drainage area is altered further to include additional drainage and if any parcels currently developed to less than 80% impervious desire to develop to the 80% level in the future. If the Lake Elmo area is excluded, 80% impervious on the Oak Park Heights undeveloped parcels would require 18.6 acres of the remaining 22.7 acres of impervious surface is available unless the drainage area is increased further. Event Existing (cfs) Proposed (cfs) West East West East 1.5 year 0.04 0.09 0.06 9.45 10 year 0.49 1.18 0.40 15.93 100 year 1.20 3.19 0.87 22.79 Page 3 217.07 BCWD Development Review W.A. T.E Office/Warehouse, Oak Park Heights Rate Control According to BCWD rule 2.4.1, part (a), it must be shown that the proposed development site will not increase peak stormwater flow for the 1.5, 10, and 100 -year, 24-hour storm events. The existing and proposed runoff rates are summarized in Table 1. Assuming that all drainage from the west storage building is adequately redirected to the east, the site drainage to the west satisfies District rate control requirements. Drainage to the east is part of the Kern Center Pond drainage area and will be analyzed below under two scenarios. Table 1: Existing and Proposed Site Runoff Rates (uydroCAD model by EOR) 1. June 2003 policy still in effect This scenario does not require any additional treatment for the site unless impervious surface is calculated on a per lot basis in which case this scenario would allow 79,031 square feet (1.8 acres) of impervious surface from the site to drain to the Kern Center Pond (80% of the existing lot drainage to Kern Center Pond). The site proposes to drain 96,871 square feet (2.2 acres) of impervious surface to the Kern Center Pond. Therefore, this scenario would require onsite treatment for 17,840 square feet (0.41 acres) of impervious surface. This will require alterations in the stormwater management plan in order to control the runoff rate to pre - development condition. 2. Kern Center Pond Cooperative Agreement applied to drainage area with drainage to other basins requiring control to meet BCWD standards. 80% impervious allowed over jitii Kern Center drainage area. The proposed project would use 2.2 of the remaining 27.0 acres of impervious surface allowed, reducing the total allowed future impervious area to 24.8 acres. To further compensate for the increased drainage area to the pond, the allowed future hard surface should be reduced to 22.7 acres. No additional treatment would be required in the Kern Center Pond area under this scenario. Volume Control According to BCWD rule 2.4.1, part (b), it must be shown that the proposed site will not increase stormwater volumes generated from a 1.5 -year, 24 -hour event, excepting that from 5% impervious cover. The existing and proposed runoff volumes are summarized in Table 2. Assuming that all drainage from the west storage building is adequately redirected to the east, the site drainage to the west satisfies District volume control requirements. Drainage to the east is part of the Kern Center Pond drainage area and will be analyzed below under two scenarios. Event Existing West (ac -ft) East Proposed West (ac --ft) East 1.5 year 0.004 0.023 0.004 0.461 Page 4 2/7/07 BCWD Development Pevieiv WA. T E Office /Warehouse, Oak Park Heights Table 2: Existing and Proposed Site Runoff volumes (HydroCAD model by EOR) 1. June 2003 policy stall in effect This scenario does not require any additional treatment for the site unless impervious surface is calculated on a per lot basis in which case this scenario would allow 79,031 square feet (1.8 acres) of impervious surface from the site to drain to the Kern Center Pond (80% of the existing lot drainage to Kern Center Pond). The site proposes to drain 96,871 square feet (2.2 acres) of impervious surface to the Kern Center Pond. Therefore, this scenario would require onsite treatment for 17,840 square feet (0.41 acres) of impervious surface. This will require alterations in the stormwater management plan in order to control the runoff volume. The additional impervious surface and the increased size of the drainage area will result in increased volume to the pond. To maintain pond functionality as designed, the additional volume generated should be fully infiltrated onsite. 2. Kern Center Pond Cooperative Agreement applied to drainage area with drainage to other basins requiring control to meet BCWD standards. 80% impervious allowed over firl Kern Center drainage area. The proposed project would use 2.2 of the remaining 27.0 acres of impervious surface allowed, reducing the total allowed future impervious area to 24.8 acres. To further compensate for the increased drainage area to the pond, the allowed future hard surface should be reduced to 22.7 acres. No additional treatment would be required in the Kern Center Pond area under this scenario. Pollutant I�oadin According to the BCWD rule 2.4.1, part (c), the proposed development must not result in an increase in total loads of suspended solids, total nitrogen, or heavy metals, or exceed the total phosphorus concentration indicated in Appendix 2.2, BCWD rules, for the site receiving water. The existing and proposed total suspended solids and phosphorus loads are summarized in Table 3. The wetland at the northwest corner of the property is a moderately susceptible wetland with a phosphorus concentration standard of 180 ppb. The phosphorus concentration standard for Long Lake is 250 ppb. Assuming that all drainage from the west storage building is adequately redirected to the east, the site drainage to the west satisfies District pollutant loading requirements. The Drainage to the east is part of the Kern Center Pond drainage area and will be analyzed below under three scenarios. Parameter Existing Proposed West East West East TSS load (lb) 0.19 1.15 0.10 1,371 TP conc. (ppb) 1 18 118 118 352 Page 5 2/7/07 BCWD D Devel opment Review—WA. T E off ice/Ware hoarse, oak Park Heights Table 3: Existing and Proposed Site TSS and TP loads (P8 model by EOR) 1. June 2003 policy still in effect This scenario does not require any additional treatment for the site unless impervious surface is calculated on a per lot basis in which case this scenario would allow 79,031 square feet (1.8 acres) of impervious surface from the site to drain to the Kern Center Pond (80% of the existing lot drainage to Kern Center Pond). The site proposes to drain 96,871 square feet (2.2 acres) of impervious surface to the Kern Center Pond. Therefore, this scenario would require onsite treatment for 17,840 square feet (0.41 acres) of impervious surface. This will require water quality treatment to control the TSS load offsite to pre -- development conditions and to maintain outflow concentration of TP of 250 ppb or less for this portion of the drainage. 2. Kern Center Pond Cooperative Agreement applied to drainage area with drainage to other basins requiring control to meet BCWD standards. 80% impervious allowed over /iiii Kern Center drainage area. The proposed project would use 22 of the remaining 27.0 acres of impervious surface allowed, reducing the total allowed future impervious area to 24.8 acres. To further compensate for the increased drainage area to the pond, the allowed future hard surface should be reduced to 22.7 acres. No additional treatment would be required in the Kern Center Pond area under this scenario. Lake/Wetland Bounce According to the BCWD rule 2.4.1, part (d), the proposed development must not increase the bounce or duration of inundation for the 1.5, 10, or 100 -year 24 hour storm event in accordance with the limit specified in Appendix 2.3 of the BCWD rules. The wetland located at the northwest corner of the property is a moderately susceptible wetland. The permitted bounce is pre - development plus % day, the permitted duration of inundation is existing plus 1 day for the 1.5 -year event and existing plus 2 days for the 10 -year event. Although the bounce and duration of inundation was not modeled for this wetland, it is unlikely that changes of the allowed magnitude would occur when the volume and rate of runoff from the site closely matches the existing condition. Rule 3°o EROSION CONTROL According to BCWD rule 3.2, all developers undertaking in land altering activities involving the movement of more than 50 cu. yd. or remove vegetation on more than 5,000 sq. ft. shall submit an erosion control plan and secure an erosion control permit from the District. Paged 217107 BCWD Development Review W.A. T E Office/Warehouse, Oak Park Heights The project will disturb about 2.5 acres of land in order to construct the buildings and associated parking. The erosion control plan includes the following: ■ Silt fence placed as appropriate along the property boundary. • Rock construction entrance. • Riprap at storinsewer outfalls and curb cuts. • Inlet protection on five of the seven proposed stormsewer inlets. To meet the BCWD erosion control requirements the following are required: ▪ Indicate the use of inlet protection on all catch basin inlets. • Provide a site revegetation schedule. ■ Provide permanent stabilization at the north end of the berm along the swale around the west storage building to prevent erosion at this location and to ensure that drainage is directed toward the Kern Center Pond. Rule 4.0 LAKE, STREAM, AND WETLAND BUFFER REQUIREMENTS Buffer zone widths are dictated by the presence of a stream or tributary of Brown's Creek and by the quality of lakes or wetlands on the development site. ■ Rule 4.0 does not apply to the proposed project. No wetlands covered under Rule 4.0 are located within or adjacent to the project area. Rule 5.0 SHORELINE AND STREAMBANK. ALTERATIONS According to BCWD rule 5.0, No person shall construct or install a shoreline or streainbank improvement below the ordinary high water mark of a waterbody, without first obtaining a District permit. ▪ Rule 5.0 does not apply to the proposed project. No work is proposed along a shoreline or stream bank. Rule 6.0 WATERCOURSE AND BASIN CROSSINGS Placement of roads, highways and utilities in the bed of any waterbody in the District requires a District permit. • Rule 6.0 does not apply to the proposed project. There are no watercourse or basin crossings proposed. Rule 7.0 FLOODPLAIN AND DRAINAGE ALTERATIONS According to BCWD rule 7.3.1 all new residential, commercial, industrial, and institutional buildings shall be constructed such that the lowest basement floor elevations are at a minimum of Page 7 217107 BCi4'D Development Review —W A. T E Offr.ce /Warehouse, Oak Park Heights two feet above the 100 --year high water elevation. The lowest grade elevation in contact with the structure can be used instead of the lowest floor only for a perched water basin, which must be demonstrated by the criteria listed under rule 7.3.1. According to BCWD rule 7.3.2 No person shall install a culvert, drainage tile, or other artificial means to remove or drain surface water without demonstrating to the District that they have provided for adequate passage and no adverse impact on upstream or downstream landowners or water quality, habitat or fisheries. The 100 -year high water level of the wetland located at the northwest corner of the site is 927.4. The building low floor elevation of 948.5 provides adequate freeboard. The project will install a culvert along Memorial Avenue. The proposed culvert is an 18" CMP. Based on a HydroCAD model developed by EOR, the proposed 18" culvert does not provide adequate capacity to maintain flow through the ditch without causing overtopping of the roadway. The model indicates that installing two 18" culverts would allow for adequate passage of the drainage from this site. Rule 8.O —FEES Fees for this project as outlined below: 1. Grading or Alteration of 1.0 .. 4.99 acres ® TOTAL FEES Rule 9.O SURETIES Sureties for this project are as outlined below: 1. Grading or Alteration (2.6 acres) TOTAL SURETIES RECOMMENDED CONDITIONS OF THE PERMIT: $1,250 $1,250 $5,200 $5,200 If the applicable policy discussed above leads to a need for significant site changes or incorporation of stormwater management facilities, it is recommended that a permit not be approved until the revised site plan is reviewed and presented to the Board of Managers. If the applicable policy discussed above does not require significant site changes, the summary of the remaining tasks necessary to bring the project into compliance with the BCWD Rule are as outlined below: Page 8 2/7/07 BCWD Development Pevieii; -WA. TE Office/Warehouse, Oak Park Heights 1. Revise entry drive culvert to prevent overtopping of the roadway and provide adequate passage of flow through the ditch. 2. Increase the height of the berm along the north end of the swale around the west storage building to ensure that the swale has adequate capacity to fully redirect drainage to the Kern Center Pond. 3. Submit revised Erosion Control Plan indicating the use of inlet protection on all catch basin inlets, providing a site revegetation schedule, and providing permanent stabilization on the berm along the swale around the west storage building to prevent erosion at this location. 4. Provide the following required surety: $5,200 for grading and alteration