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HomeMy WebLinkAboutWPO201500090 Calculations Minor Amendment 2016-03-28 GLENMORE K2B, LOTS 1 & 7-16 STORMWATER MANAGEMENT AMENDMENT CALCULATIONS PACKET Date of Calculations OCTOBER 15, 2015 Revised on January 6, 2016 (Revisions noted in yellow and ) March 28, 2016 (Revisions noted in grey) PREPARED BY: COLLINS 200 GARRETT STREET, SUITE K CHARLOTTESVILLE, VA 22902 434.293.3719 PH 434.293.2813 FX www.collins-engineering.com Stormwater Management Summary: OVERALL: The proposed stormwater management(SWM)facility#2 proposed with this amendment is designed to replace the previously approved SWM facilities#2&#3.This amended facility is located immediately downstream of the previously approved facilities, but is strategically located to treat more runoff with less grading impacts. The approved WPO plan provides quality and quantity treatment for lots 1-16,with this runoff generally separated into the following three sections: A. Runoff draining to the approved&constructed facility adjacent to Lot 1.This section of the development is treated and is not modified with this amendment. B. Runoff draining from the rear portions of lots 2-6.This section of the development is not treated and is not modified with this amendment. C. Runoff draining from lots 7-16.This section of the development is not modified, but the downstream facilities treating this section are what are modified with this amendment. Section C described above is separated into two parts,the runoff being released untreated (subarea A) and the runoff being treated(subarea B).The previously approved facilities treated a combined 10.80 acres and this facility treats 10.83 acres during the proposed (interim)phase, and 13.97 acres upon final buildout of its watershed. QUALITY: The amendment's SWM facility has an interim stage where it treats only this development. However the final buildout of this facility's watershed will incorporate runoff from an adjacent development adhering to current requirements.As such,the design of this facility was upgraded for a future credit to adhere to the Virginia Stormwater BMP Clearinghouse specification#14. The Virginia Runoff Reduction Method(VRRM)calculations for this fedevelopment were utilized for this analysis. utilized.(Note:The amended facility treats runoff from the existing Carrot Creek Road with the upgraded dcsigr--} Using a project area in the VRRM's 'site data'tab equal to 12.50 acres lots 7-16's area for the interim stage,the required phosphorous removal rate is 3.70 lbs/yr. : -: - e . - : - -- - - • .•: cubar as A&B.} The use of the - - - ._e - - - - - -- - . . - - . .. - - - - -. • . . - - - an-e14-14e amended Level 2 retention basin results in a total phosphorous removal of 6.11 lbs/yr. Therefore making this facility compliant for the interim stage. Once the future development is proposed for final site plan review,the water quality compliance for this parcel as a whole will be evaluated by County Engineering. However at this time the affixed amendment plan is designed to be approved for a final buildout treatment volume of 21,990 cf.The final buildout's VRRM 'site data'tab has a project area equal to the sum of the proposed lots 7-16,the future lots 52-62 and their respective roads and the open space between these lots and the proposed SWM easement. (Note:This amended facility is oversized and plan). provides a 2.3 lbs/yr.water quality credit that may be applied to the future 62 lot development. QUANTITY: This amendment's SWM facility was analyzed for the interim stage of development,as well as for the final buildout. Subareas A& B release post-development runoffs into the downstream channel less than or equal to the pre-development 2-year design storm events.These 2-year post-development runoffs are also less than what was previously approved to be released.Additionally,the 1-year post-development runoffs released from subareas A& B are less than a hypothetical pre-development forested watershed. In accordance with section 9VAC25-870-66, "under no condition shallQDeveloped be greater than QFre-Developed nor shall QDeveloped be required to be less than that calculated in the equation (QForest* RVForest)/RVDeveloped. SCS TR-55 Calculations Soils Mapping (Source: NRCS Web Soil Survey Online Database) • • 1 }f Soils Table (Source: NRCS Web Soil Survey Online Database) Albemarle County,Virginia (VA003) Map Unit Map Unit Name Percent Symbol of AOI 518 Manteo charmer,/silt loam, 14.0% 2 to 7 percent slopes 5:C Manteo channery silt loam, 49.9% 7 to 15 percent slopes 62B Nason silt loam.2 to 7 36.:00 percent slopes Totals for Area of Interest 100.0% Note: Soils' properties witin proposed disturbances are predominantly composed of hydrologic type D soils. Virginia Runoff Reduction Method Calculations (Interim Stage) Virginia Runoff Reduction Method New Development Worksheet-v2.8 -June 2014 To be used w/2011 BMP Standards and Specifications Site Data Project Name: Glenmore K2B, Lots 7-16 SWM Amendment(INTERIM STAGE) Date: 1/6/15 data input cells calculation cells constant values 1. Post-Development Project& Land Cover Information Constants Annual Rainfall(inches) 43 Target Rainfall Event(inches) 1.00 • Phosphorus EMC(mg/L) 0.26 Nitrogen EMC(mg/L) 1.86 Target Phosphorus Target Load(Ib/acre/yr) 0.41 Pj 0.90 Land Cover (acres) A soils B Soils C Soils D Soils Totals Forest/Open Space(acres)-undisturbed, protected forest/open space or reforested land 0.00 0.00 0.00 0.00 0.00 'Managed Turf(acres)-disturbed,graded for yards or other turf to be mowed/managed 0.00 0.00 0.00 7.99 7.99 Impervious Cover(acres) 0.00 0.00 0.00 1.38 1.38 Total 9.37 Rv Coefficients A soils B Soils C Soils D Soils I Forest/Open Space 0.02 0.03 0.04 0.05 Managed Turf 0.15 0.20 0.22 0.25 Impervious Cover 0.95 0.95 0.95 0.95 Land Cover Summary Forest/Open Space Cover(acres) 0.00 Weighted Rv(forest) 0.00 %Forest 0% Managed Turf Cover(acres) 7.99 Weighted Rv(turf) 0.25 Managed Turf 85% Impervious Cover(acres) 1.38 _ Rv(impervious) 0.95 %Impervious 15% _ Total Site Area(acres) 9.37 Site Rv 0.35 Post-Development Treatment Volume(acre-ft) 0.28 Post-Development Treatment Volume(cubic feet) 12,003 Post_Development Load(TP)(Ib/yr) 7.54 Post_Development Load(TN)(Ib/yr Total Load(TP)Reduction Required(Ib/yr) 3.70 .nbpe Ane. --...- ---. o..no ... 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O.0 xrtcc.x wrwu•0�s n} Virginia Runoff Reduction Method Worksheet Virginia Runoff Reduction Method New Development Worksheet-v2.8-June 2014 Site Data Summary Total Rainfall= 43 inches Site Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 0.00 0.00 7.99 7,99 85.30 Impervious(acres) 0.00 0.00 0.00 1.38 1.38 14.70 9.37 100.00 Sum of Drainage Areas is greater than Total Site Area Site Rv 0.35 Post Development Treatment Volume(ft3) 12003 Post Development TP Load(Ib/yr) 7.54 Post Development TN Load(Ib/yr) 53.95 Total TP Load Reduction Required(Ib/yr) 3.70 Total Runoff Volume Reduction(ft') 0 Total TP Load Reduction Achieved(Ib/yr) 6 Total TN Load Reduction Achieved(Ib/yr) 23.31 Adjusted Post Development TP Load(Ib/yr) 1.43 Remaining Phosphorous Load Reduction(Lb/yr)Required 0.00 Drainage Area Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00- 9.59 0.00 0.00 0.00 9,59 Impervious(acres) 0.00 1.24 0.00 0.00 0.00 1.24 10.83 Drainage Area Compliance Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total TP Load Red.(Ib/yr) 0.00 6.11 0.00 0.00 0.00 6.11 TN Load Red.(Ib/yr) 0.00 23.31 0.00 0.00 0.00 23.31 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area B Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 0.00 0.00 9.59 9.59 88.55 Impervious(acres) 0.00 0.00 0.00 1.24 1.24 11.45 10.83 BMP Selections Practice Credit Area(acres) Downstream Practice 13.c.Wet Pond#2(Spec#14) Impervious: 1.24 Turf(Pervious): 9.59 Total Impervious Cover Treated(acres) 1.24 Total Turf Area Treated(acres) 9.59 • Total TP Load Reduction Achieved in D.A.A(Ib/yr) 6.11 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 23.31 Summary Print Virginia Runoff Reduction Method Calculations (Final Buildout) Virginia Runoff Reduction Method New Development Worksheet-v2.8-June 2014 To be used w/2011 BMP Standards and Specifications Site Data Project Name:Glenmore K2B,Lots 7-16 SWM Amendment(FINAL BUILDOUT STAGE) Date: 1/6/15 data input cells calculation cells constant values 1. Post-Development Project& Land Cover Information Constants Annual Rainfall(inches) 43 _ Target Rainfall Event(inches) 1.00 Phosphorus EMC(mg/L) 0.26 Nitrogen EMC(mg/L) 1.86 Target Phosphorus Target Load(lb/acre/yr) 0.41 Pj 0.90 Land Cover (acres) A soils B Soils C Soils D Soils Totals Forest/Open Space(acres)-undisturbed, protected forest/open space or reforested land 0.00 0.00 0.00 0.00 0.00 Managed Turf(acres)-disturbed,graded for yards or other turf to be mowed/managed 0.00 0.00 0.00 10.87 10.87 Impervious Cover(acres) 0.00 0.00 0.00 3.6� 3.60 Total 14.47 Rv Coefficients A soils B Soils C Soils D Soils Forest/Open Space 0.02 0.03 0.04 0.05 Managed Turf 0.15 0.20 0.22 0.25 Impervious Cover 0.95 0.95 0.95 0.95 Land Cover Summary Forest/Open Space Cover(acres) 0.00 Weighted Rv(forest) 0.00 Forest 0% I Managed Turf Cover(acres) 10.87 Weighted Rv(turf) 0.25 %Managed Turf 75% Impervious Cover(acres) 3.60 Rv(impervious) 0.95 %Impervious 25%_ Total Site Area(acres) 14.47 Site Rv 0.42 Post-Development Treatment Volume(acre-ft) 075T Post-Development Treatment Volume(cubic feet) 22,287 Post_Development Load(TP)(lb/yr) 14.00 Post_Development Load(TN)(Ib/yrOJ 100.171 Total Load(TP)Reduction Required(Ib/yr) 8.07 .peen.O... .eu o..wpm..r..mnm vavm.111111 --- --- Apply Runoff Reduction .e to Reduce I onL Treatment Volume&pevobtm L rea 9 1.... w. 0...,.nc.e. cb. �.. .,...a ....m.. vo.m. e .K x.><,..m m r...<.m.m m. n�.,,.m.,r..,.....m. a x1 . .........:..1....0..i m.1 1..v.nu.e M n..s e. sworn eel .e.so.s..:ava.l OM 0.00 0 0 a 0 0.00 0m 0.w , 0m 0 000 0.w ow 000 vs0. 412.4.61 0 0m Ow 0w Ow 0__ am Ow O.w0.00 -- rsnv gs ..e s 050 000 0 0 0 a 0.00 000 am OM 0 Om am 0.m 000 . :5.s.P s.111.1. 1...m.s 050 Om 0 0 0 0 Ow am am am 0 am 0.m 000 0.00 sy eq.. els 0.50 0 0 , 0 a 0 25 am 000 0m 000 15 0.w 0 0 0w 0.00 24 ant tureemPere ma.. n,:eo...:n nlswes It..... 090 0w 0 0 0 25 0m Ow 0w 0w 15 0,00 Ow 000 0.00 ...m.nilisw� .rws 020 000 0 a 0 w Ow Om 0m aoo 0 Om am 000 Ow ,mmo............... .:w... 000 0.m 0 0 0 0 0m 0m 000 000 0 0.w 000 000 000 en.allgss..e.m 0.40 0.m 0 0 a 25 Om OW ODD 000 40 am Om 0w 000 .sp M s.m mer 0m 0.00 0 0 0 15 0.w 0.w 0.00 000 w 000 0.00 000 0m S.00 0.1/1 y.nq . s....n.:o.T 0w 000 0 0 0 00 a.w woo 0m 000 25 000 000 000 000 Se Def..lirme 11/01 EIMIIIIIIIIIIIIIII all 0.14.en,,eret en r..oanAs Ao .eM... 00..41..... 0.50 Ow 0 a 0 25 000 am 0.00 Ow 15 000 0.00 Ow 000 as..en 1104......., 050 OM 0 0 a 25 0.00 OW am Om 15 o.w Ow am Om e.Extended Detention wnly... 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'''''''Itle"'12'5111 P'" PM sow an.re146.02.1.Vs 65.1..... 0 00 0 00 0 0 0 45 0 00 000 0 00 0 210 20 0 00 0 00 000 0 00 . ...A 6.2.6,...,5. 6. 01"6...... 0 00 3 168 0 0 130,161 75 000 8 57 842 2 14 40 0 00 81 28 24 51 38 1> 40 0 00 37.45 14 011 22 47 m 0,11.21,W.U.I.I.L.01 0 00 0 OD 0 0 66 OM 000 000 000 30 0 DO 0 00 0 00 0 00 _ 0 00 0 00 0 00 0 DD 71265 21.21/0210.,„.„...00v....E11,,,222...tEo,....itU 1 6.2264,014.6t6_ __ ____61154_11,61_10,1701,17111,12.211,017;13.2.T.10002112.0226,0111.12 r allirEM SEE WATER QUALM'COWL/MICE TAB FOR SITE COMPLIA.E CALCULATION!, , 221202.606111.100.111'712...74.7%0,11:12600012=:=0.2Z1 ::: i Virginia Runoff Reduction Method Worksheet Virginia Runoff Reduction Method New Development Worksheet-v2.8-June 2014 Site Data Summary Total Rainfall=43 inches Site Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 0.00 0.00 10.87 10.87 75.10 Impervious(acres) 0.00 0.00 0.00 3.60 3.60 24.90 14.47 100.00 Site Rv 0.42 Post Development Treatment Volume(ft3) 22287 Post Development TP Load(Ib/yr) 14.00 Post Development TN Load(Ib/yr) 100.17 Total TP Load Reduction Required(Ib/yr) 8.07 Total Runoff Volume Reduction(ft') 0 Total TP Load Reduction Achieved(lb/yr) 10 Total TN Load Reduction Achieved(lb/yr) 39.49 Adjusted Post Development TP Load(Ib/yr) 3.65 Remaining Phosphorous Load Reduction(Lb/yr)Required 0.00 Drainage Area Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 9.19 0.00 0.00 0.00 9.19 Impervious(acres) 0.00_ 3.96 0.00 0.00 0.00 3.96 13.15 Drainage Area Compliance Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total TP Load Red.(lb/yr) 0.00 10.35 0.00 0.00 0.00 10.35 TN Load Red.(Ib/yr) 0.00 39.49 0.00 0.00 0.00 39.49 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area B Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.00 0.00 0.00 0.00 0.00 Turf(acres) 0.00 0.00 0.00 9.19 9.19 69.90 Impervious(acres) 0.00 0.00 0.00 3.96 3.96 30.10 13.15 BMP Selections Practice Credit Area(acres) Downstream Practice 13.c.Wet Pond#2(Spec#14) Impervious: 3.957759 Turf(Pervious): 9.192241 Total Impervious Cover Treated(acres) 3.96 Total Turf Area Treated(acres) 9.19 Total TP Load Reduction Achieved in D.A.A(lb/yr) 10.35 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 39.49 Summary Print Channel Protection Compliance U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 2:Runoff Curve Number and Runoff Project: Glenmore Lots 1&7-16 SWM Amendment Designed By:FGM,PE Date: 1/6/2016 Location: Carroll Creek Road Checked By:SRC,PE Date: 1/6/2016 Check C Present X Devel X 1.Runoff curve Number(CN) Drainage Area Soil name and Cover description Area Product of CN CN(weighted)= Calculated'S' hydrologic group (Cover type,treatment,and hydrologic condition;percent impervious; CN total product/total Description (Acres) x Area Value (Appendix A) unconnected/connected impervious area ratio) area DA A&B (Forest) Forested Conditions:For Channel Protection Compliance Calcs Only 77 13.94 1073.4 77.0 2.99 DAA Imp.Areas:Carroll Creek Rd(Not part of this plan) 98 0.19 18.4 (Pre-Dev.) D Woods in Good Condition 77 2.17 167.2 79.0 2.66 Lawns in Good Condition(75%+Groundcover) 80 0.72 57.6 DAB Imp.Areas:Carroll Creek Rd(Not part of this plan) 98 0.34 33.3 (Pre-Dev.) D Woods in Good Condition 77 7.09 545.9 78.2 2.78 Lawns in Good Condition(75%+Groundcover) 80 1.11 88.8 DAA Imp.Areas:Carroll Creek Rd+Lot 7 98 0.17 17.0 (Post-Dev.) D Woods in Good Condition 77 0.00 0.0 83.9 1.91 Lawns in Good Condition(75%+Groundcover) 80 0.62 49.3 DAB Imp.Areas:Carroll Creek Rd+Lot 8-16 98 1.73 169.7 (Interim) D Woods in Good Condition 77 0.00 0.0 82.9 2.07 Lawns in Good Condition(75%+Groundcover) 80 9.10 727.8 DAB Imp.Areas:Carroll Creek Rd+Lots 8-16+Fut.Lots 52-62&their roads 98 3.96 387.9 (Full Buildout) D Woods in Good Condition 77 0.00 0.0 85.1 1.75 Lawns in Good Condition(75%+Groundcover) 80 10.01 801.0 2.Runoff 1-Year Storm 2-Year Storm 10-Year Storm Drainage Area Description Frequency-years 1 2 10 n/a Rainfall,P(24 hour)-inches 3.5 3.7 5.6 n/a Runoff,Q-inches 1.43 1.58 3.13 DA A&B(Forest) Runoff,Q-inches 1.56 1.72 3.32 DA A(Pre-Dev.) Runoff,Q-inches 1.51 1.67 3.25 DAB(Pre-Dev.) Runoff,Q-inches 1.93 2.10 3.82 DAA(Post-Dev.) Runoff,0-inches 1.85 2.02 3.71 DAB(Interim) Runoff,Q-inches 2.02 2.20 3.94 DAB(Full Buildout) U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 3:Time of Concentration(1,)or Travel Time(T5) Project: Glenmore Lots 1&7-16 SWM Amendment Designed By:FGM,PE Date: 12/18/2015 Location: Carroll Creek Road Checked By:SRC,PE Date: 12/18/2015 Check One: Present X Developed X Check One: T, X T, Through subarea n/a DAA&B DAA DAB DAA DAB DAB Segment ID: (Forest) (Pre-Dev.) (Pre-Dev.) (Post-Dev.) (Interim) (Full Buildout) Sheet Flow:(Applicable to T,only) Woods-Light Woods-Light Woods-Light Woods-Light 1 Surface description(Table 3-1) Underbrush Underbrush Underbrush Dense Grass Underbrush Dense Grass 2 Manning's roughness coeff.,n(Table 3-1 0.4 0.4 0.4 0.24 0.4 0.24 3 Flow length,L(total L<100)(ft) 100 100 100 100 100 100 4 Two-year 24-hour rainfall,P2(in.) 3.7 3.7 3.7 3.7 3.7 3.7 5 Land slope,s(ft/ft) 0.035 0.04 0.035 0.05 0.035 0.035 6 Compute T,_[0.007(n*L)°B]/1,20•5 s°° 0.27 0.252 0.27 0.153 0.27 0.18 Shallow Concentrated Flow: 7 Surface description(paved or unpaved) Unpaved Unpaved Unpaved Unpaved Unpaved Unpaved 8 Flow Length,L(ft) 825 295 825 60 500 500 9 Watercourse slope,s(ft/ft) 0.070 0.129 0.070 0.200 0.088 0.088 10 Average velocity,V(Figure 3-1)(ft/s) 4.3 5.8 4.3 7.2 4.2 4.8 11 Tt=L/3600*V 0.05 I 0.014 I 0.05 I 0.002 I 0.03 I 0.03 Channel Flow: 12 Cross sectional flow area,a(ft2) 13 Wetted perimeter,P,,,(ft) 14 Hydraulic radius,r=a/Pw(ft) 15 Channel Slope,s(ft/ft) 16 Manning's Roughness Coeff,n 17 V=[1.49r2/2s°'s]/n 18 Flow length,L(ft) 19 T,=L/3600*V I I I I I I 20 Watershed or subarea T,or Tt (Add T,in steps 6,11 and 19) 0.32 I 0.27 I 0.32 I 0.16 I 0.30 I 0.21 I U.S.Department of Agriculture FL-ENG-21C Natural Resources Conservation Service 06/04 TR 55 Worksheet 4:Graphical Peak Discharge Method Project: Glenmore Lots 1&7-16 SWM Amendment Designed By:FGM,PE Date: 1/6/2016 Location: Carroll Creek Road Checked By:SRC,PE Date: 1/6/2016 Check One: Present X Developed X Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area Drainage Area 1.Data Description Description Description Description Description Description DAA&B DAA DAB DAA DAB DA B (Forest) (Pre-Dev.) (Pre-Dev.) (Post-Dev.) (Interim) (Full Buildout) Drainage Area(Am)in miles 2= 0.0218 0.0048 0.0133 0.0012 0.0169 0.0218 Runoff curve number CN= 77.0 79.0 78.2 83.9 82.9 85.1 Time of concentration(Tc). 0.32 0.27 0.32 0.16 0.30 0.21 Rainfall distribution type= II II II II II II Pond and swamp areas spread 0 0 0 0 0 0 throughout the watershed= 2.Frequency-years 1 2 10 1 2 10 1 2 10 1 2 10 1 2 10 1 2 10 3.Rainfall,P(24 hour)-inches 3.5 3.7 5.6 3.5 3.7 5.6 3.5 3.7 5.6 3.5 3.7 5.6 3.5 3.7 5.6 3.5 3.7 5.6 4.Initial Abstraction,la-inches 0.60 0.60 0.60 0.53 0.53 0.53 0.56 0.56 0.56 0.38 0.38 0.38 _ 0.41 0.41 0.41 0.35 0.35 0.35 5.Compute la/P 0.17 0.16 0.11 0.15 0.14 0.10_ 0.16 0.15 0.10 0.11 0.10 0.07 0.12 0.11 0.07 0.10 0.09 0.06 6.Unit peak discharge,Qs-csm/in 625 650 675 700 700 725 650 650 675 850 875 875 650 675 675 _ 775 775 800 7.Runoff,Q from Worksheet 2-inches 1.43 1.58 3.13 1.56 1.72 3.32.. 1.51 1.67 3.25 1.93 2.10 3.82 1.85 2.02 3.71 2.02 2.20 3.94 8.Pond and Swamp adjustment factor,Fp 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 9.Peak Discharge,Qp-cfs Routed Through Routed Through where Qp=Qu Am Q Fp 19.47 22.38 46.05 5.27 5.80 11.59 13.12 14.46 29.27 2.03 2.27 4.12 SWM Facility SWM Facility Watershed Summary Pre-Development Area,ac. CN Time of 1-yr.Flow,cfs 2-yr.Flow,cfs Conc.,hrs. Subarea A 3.08 79.0 0.27 5.27 5.80 Subarea B 8.54 78.2 0.32 13.12 14.46 Post-Development Area,ac. CN Time of Conc.,hrs. _1-yr.Flow,cfs 2-yr.Flow,cfs Subarea A 0.79 83.9 0.16 2.03 2.27 Subarea B,Interim 10.83 82.9 0.30 0.90 1.07 Subarea B,Final Buildout 13.97 85.1 0.21 2.23 4.41 C1-kRNNE.1..'q0r`c-czon► -.0.-..r., _ ,. . \0(\ i'i5 A'fi�R.'THAN G� ‘i61�6 ��c�.��+r AtQ 5tstkN b3/*UNOEk NO ConnDY: on} SFtAu Q9v4<14,Peo G/tgppm.pE,Ec sr., 1(CA) N,cR St+1=0-4- &ptuEt.oQEO • R C-v3 AtE4'"� 10 Sg. LESS TNAr r 11% CA1-Cc+LATE,0 ON'�•tl EavAncn, Cees- k ' ix-st) /Ne4aDszo.41 ANALN VS 14i% hat.Qp[-J C 4 QW- . Qes) = �a U il�-1 Q k=J Q,pE;v, ' G Qom.,, G 5.ah -- 13.1a _ a.o3 +-6.R3' _ D.03 4 46- , a a M . Q; v. '_ Qce,v aNACCSzS 4d z. MAx, Qv • CQsTXR�rcims) wi-C- Q tik 4ccsct+AR , SEE WbRkSKt op-TR-5.5 'RV wi. SCS MEt ( L ) RV •r e uNoF'f`, S .E h10RKSEe-f Q Tit.-55.5CS 6,9.4ri 7Sl (t.4a tnchQS> mc-rtiao C i rches� k3 ss -T- is 1r01V: k- --v,c.. COI cfsc E *kN pE„.4 "RL.r,ksr 5 ic,r2w: ( r !Lk.n:, .moi-Ac. 8vz�c*�,�Qom,,, MAx Gke,), CNw= - (cuu., ca ,.0o"'Y� / 8'1 ',l (1"1- 1` Qpt, c f�1Rx . V Qte, CN),,, = v4 CN C IQ.,= f8 a.9l1a.$i) A-(83.gYo,r\c 11,ea Ac, ChL)= 8 .0 CS a ( voev _ ic) - o.a(s) wHtat ' 3.5 ? +0.8(s s. _ /1/4110s coNsRVR-v-ave .♦ (1/4FuL.d ,tc* � g, j. " ii.-:eq ,,renes ‘,,,JK .-UE 5,Ft„wSua,Pa I s };4F3- N-celsnr \' ``I .,,, 5,g,,b-m-Rw"A _c a.n 5 Post-Development Routing Calculations for the Interim Stage and the Final Buildout Glenmore K2B SWM Amendment- Lots 1 & 7-16 BasinFlow printout INPUT: Basin: Interim Glenmore K2B SWM Amendment- Lots 1 & 7-16 4 Contour Areas Elevation(ft) Area(sf) Computed vol . (cy) 334.00 13550.00 0.0 336.00 19300.00 1210.4 338.00 25190.00 2853.3 340.00 31484.00 4948.1 Start_Elevation(ft) 334.00 Vol . (cy) 0.00 5 Outlet Structures Outlet structure 0 Orifice name: Barrel area (sf) 4.909 diameter or depth (in) 30.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 329.080 multiple 1 discharge out of riser Outlet structure 1 Orifice name: 3" Low-Flow Orifice area (sf) 0.049 diameter or depth (in) 3.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 334.000 multiple 1 discharge into riser Outlet structure 2 Orifice name: 7" Midflow Orifice area (sf) 0.267 diameter or depth (in) 7.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 336.250 multiple 1 discharge into riser Outlet structure 3 weir name: Riser diameter (in) 42.000 side angle 0.000 coefficient 3.300 invert (ft) 337. 500 multiple 1 discharge into riser transition at (ft) 1.063 orifice coef. 0. 500 orifice area (sf) 9.621 Page 1 Glenmore K2B SWM Amendment- Lots 1 & 7-16 Outlet structure 4 Weir name: Emergency Spillway length (ft) 45.000 side angle 75.960 coefficient 3.300 invert (ft) 338. 500 multiple 1 discharge through dam 4 Inflow Hydrographs Hydrograph 0 SCS name: 1-yr SCS Peak 24 hr. Storm Event- Interim Stage Area (acres) 10.830 CN 82.900 Type 2 rainfall , P (in) 3. 500 time of conc. (hrs) 0.3000 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 18.958 peak time (hrs) 12.010 volume (cy) 2691.744 Hydrograph 1 SCS name: 2-yr SCS Peak 24 hr. Storm Event- Interim Stage Area (acres) 10.830 CN 82.900 Type 2 rainfall , P (in) 3.700 time of conc. (hrs) 0.3000 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 20.690 peak time (hrs) 12.010 volume (cy) 2937.663 Hydrograph 2 SCS name: 10-yr scs Peak 24 hr. storm Event- Interim Stage Area (acres) 10.830 CN 82.900 Type 2 rainfall , P (in) 5.600 time of conc. (hrs) 0.3000 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 38.017 peak time (hrs) 12.010 volume (cy) 5397.764 Page 2 Glenmore K2B SWM Amendment- Lots 1 & 7-16 Hydrograph 3 SCS name: 100-yr SCS Peak 24 hr. Storm Event- Interim Stage area (acres) 10.830 CN 82.900 Type 2 rainfall , P (in) 9.100 time of conc. (hrs) 0.3000 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 71.909 peak time (hrs) 12.010 volume (cy) 10209.974 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1-yr SCS Peak 24 hr. Storm Event- Interim Stage inflow (cfs) 18.848 at 12.02 (hrs) discharge (cfs) 0.900 at 13.76 (hrs) water level (ft) 336.830 at 13.80 (hrs) storage (cy) 1839.822 Hydrograph 1 Routing Summary of Peaks: 2-yr SCS Peak 24 hr. Storm Event- Interim Stage inflow (cfs) 20. 570 at 12.02 (hrs) discharge (cfs) 1.068 at 13. 52 (hrs) water level (ft) 337.011 at 13.64 (hrs) storage (cy) 1985.936 Hydrograph 2 Routing Summary of Peaks: 10-yr SCS Peak 24 hr. Storm Event- Interim Stage inflow (cfs) 37.796 at 12.02 (hrs) discharge (cfs) 16. 573 at 12.24 (hrs) water level (ft) 338.052 at 12.24 (hrs) storage (cy) 2901.639 Hydrograph 3 Routing Summary of Peaks: 100-yr SCS Peak 24 hr. Storm Event- Interim Stage inflow (cfs) 71.492 at 12.02 (hrs) discharge (cfs) 63. 531 at 12.08 (hrs) water level (ft) 338.746 at 12.08 (hrs) storage (cy) 3580.462 Tue Jan 05 10:48:46 EST 2016 Page 3 FINAL BUILDOUT- Glenmore K2B SWM Amendment- Lots 1 & 7-16 BasinFlow printout INPUT: Basin: FINAL BUILDOUT- Glenmore K2B SWM Amendment- Lots 1 & 7-16 4 Contour Areas Elevation(ft) Area(sf) Computed vol . (cy) 334.00 13550.00 0.0 336.00 19300.00 1210.4 338.00 25190.00 2853.3 340.00 31484.00 4948.1 Start_Elevation(ft) 334.00 Vol . (cy) 0.00 5 Outlet Structures Outlet structure 0 Orifice name: Barrel area (sf) 4.909 diameter or depth (in) 30.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 329.080 multiple 1 discharge out of riser Outlet structure 1 orifice name: 3" Low-Flow Orifice area (sf) 0.049 diameter or depth (in) 3.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 334.000 multiple 1 discharge into riser Outlet structure 2 Orifice name: 7" Midflow Orifice area (sf) 0.267 diameter or depth (in) 7.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 336.250 multiple 1 discharge into riser Outlet structure 3 Wei r name: Riser diameter (in) 42.000 side angle 0.000 coefficient 3.300 invert (ft) 337. 500 multiple 1 discharge into riser transition at (ft) 1.063 orifice coef. 0. 500 orifice area (sf) 9.621 Page 1 FINAL BUILDOUT- Glenmore K2B SWM Amendment- Lots 1 & 7-16 Outlet structure 4 weir name: Emergency Spillway length (ft) 45.000 side angle 75.960 coefficient 3.300 invert (ft) 338. 500 multiple 1 discharge through dam 4 Inflow Hydrographs Hydrograph 0 SCS name: 1-yr SCS Peak 24 hr. Storm Event- Final Buildout Area (acres) 13.970 CN 85.100 Type 2 rainfall , P (in) 3. 500 time of conc. (hrs) 0.2100 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 30.318 peak time (hrs) 11.982 volume (cy) 3798.789 Hydrograph 1 SCS name: 2-yr SCS Peak 24 hr. Storm Event- Final Buildout Area (acres) 13.970 CN 85.100 Type 2 rainfall , P (in) 3.700 time of conc. (hrs) 0.2100 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 32.946 peak time (hrs) 11.982 volume (cy) 4128.067 Hydrograph 2 SCS name: 10-yr SCS Peak 24 hr. Storm Event- Final Buildout Area (acres) 13.970 CN 85.100 Type 2 rainfall , P (in) 5.600 time of conc. (hrs) 0.2100 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 58.957 peak time (hrs) 11.982 volume (cy) 7387.185 Page 2 FINAL BUILDOUT- Glenmore K2B SWM Amendment- Lots 1 & 7-16 Hydrograph 3 SCS name: 100-yr SCS Peak 24 hr. Storm Event- Final Buildout Area (acres) 13.970 CN 85.100 Type 2 rainfall , P (in) 9.100 time of conc. (hrs) 0.2100 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 109.186 peak time (hrs) 11.982 volume (cy) 13680.818 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1-yr SCS Peak 24 hr. Storm Event- Final Buildout inflow (cfs) 30.296 at 11.98 (hrs) discharge (cfs) 2.225 at 12.80 (hrs) water level (ft) 337. 577 at 12.80 (hrs) storage (cy) 2468.644 Hydrograph 1 Routing Summary of Peaks: 2-yr SCS Peak 24 hr. Storm Event- Final Buildout inflow (cfs) 32.922 at 11.98 (hrs) discharge (cfs) 4.413 at 12.42 (hrs) water level (ft) 337.685 at 12.42 (hrs) storage (cy) 2565.494 Hydrograph 2 Routing Summary of Peaks: 10-yr SCS Peak 24 hr. Storm Event- Final Buildout inflow (cfs) 58.914 at 11.98 (hrs) discharge (cfs) 40.445 at 12.08 (hrs) water level (ft) 338. 528 at 12.08 (hrs) storage (cy) 3361.499 Hydrograph 3 Routing Summary of Peaks: 100-yr SCS Peak 24 hr. Storm Event- Final Buildout inflow (cfs) 109.106 at 11.98 (hrs) discharge (cfs) 102.477 at 12.02 (hrs) water level (ft) 338.993 at 12.02 (hrs) storage (cy) 3835.146 Tue Jan 05 10:46: 51 EST 2016 Page 3