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HomeMy WebLinkAbout20051046 Ver 2_Stormwater Info_20080414~x.p o$-10~~, V2 Womble Farms Subdivision pastern Lod sales l~~ky IVlount, N~ X7804 STOCKS ENGINEERING, P.A. 1100 Eastern avenue Phone: 252.459.8196 PO Box 1108 Fax: 252.459.8197 Nashville, NC 27856 Mobile: 252.903.6891 Email: mstocks@stocksengineering.com > 1 Y Rn ~ 1 • rL ~"~ -:~i;- i ~~ . _ ~ .~ ff ~" , t .. f. 4' 1 Womble Farms Subdivision a C~~~-~ D c~ ~,~ ~; ~ 4 2.008 S~T'i?4~ ~rw , at lr ~ `~ r f 1 Yt ry z ~ ~P~ ,~ ~?7'. Y_ p.,, y ~5 r _~ ~. ~~ n , r f~ Y ~+. E + ~ ~ ~~~~~ r.'1 - ~ ~\`4-~.t~'~.'Auaac~at+a~ a6=ai /r, `~;~s b xr o v, t y F ~ to ~ O \ l,..r ~ ~1 ~~ (~1: y a ~' ~ ~ ~ ~ a _~ M m z <<~f5r c t.. STOCKS ENGINEERING, P.A. • 1100 Eastern avenue PO Box 1108 Nashville, NC 27856 Phone: 252.459.8196 Fax: 252.459.8197 Mobile: 252.903.6891 Email: mstocks@stocksengineering.com • Stocks Engineering, P.A. 1100 Eastern Avenue PO Box 1108 Nashville. NC 27856 • Project: Womble Farms Date: March 7, 2008 Page:1 of 4 Post-Development 5 la 0.10 0.67 5.6 0.38 5 Ib 0.44 0.62 5.6 1.53 5 Ila 4.94 0.35 5.6 9.68 5 Illa 2.14 0.36 5.6 4.31 5 Illb 0.38 0.43 5.6 0.92 5 Illc 0.62 0.67 5.6 2.33 5 Illd 1.1 0.67 5.6 4.13 5 Ille 0.33 0.43 5.6 0.79 5 Illf 0.15 0.67 5.6 0.56 5 Illg 1.02 0.35 5.6 2.00 5 Illh 5.67 0.35 5.6 11.11 5 Illi 6.38 0.35 5.6 12.50 5 Illj 0.27 0.67 5.6 1.01 5 Illk 0.11 0.67 5.6 0.41 5 IIII 0.16 0.47 5.6 0.42 5 Illm 1.00 0.39 5.6 2.18 5 Illn 0.30 0.35 5.6 0.59 5 Illo 0.34 0.35 5.6 0.67 5 Illp 0.46 0.42 5.6 1.08 5 Illq 0.22 0.67 5.6 0.83 5 Illr 1.00 0.35 5.6 1.96 5 IVa 1.95 0.46 5.6 5.02 5 IVb 2.97 0.37 5.6 6.15 5 IVc 7.48 0.35 5.6 14.66 6 IVd 1.54 0.36 5.6 3.10 - Total 39.b3 - 5.6 85.23 Runoff Computations 2-Year Storm • • Stocks Engineering, P.A. 1100 Eastern Avenue PO Box 1108 Nashville. NC 27856 • Nost- uevelopment 5 la 0.10 0.67 7.6 0.51 5 Ib 0.44 0.62 7.6 2.07 5 Ila 4.94 0.35 7.6 13.14 5 Illa 2.14 0.36 7.6 5.86 5 Illb 0.38 0.43 7.6 1.24 5 Illc 0.62 0.67 7.6 3.16 5 Illd 1.1 0.67 7.6 5.60 5 Ille 0.33 0.43 7.6 1.08 5 Illf 0.15 0.67 7.6 0.76 5 Illg 1.02 0.35 7.6 2.71 5 Illh 5.67 0.35 7.6 15.08 5 Illi 6.38 0.35 7.6 16.97 5 Illj 0.27 0.67 7.6 1.37 5 Illk 0.11 0.67 7.6 0.56 5 IIII 0.16 0.47 7.6 0.57 5 Illm 1.00 0.39 7.6 2.96 5 Illn 0.30 0.35 7.6 0.80 5 Illo 0.34 0.35 7.6 0.90 5 Illp 0.46 0.42 7.6 1.47 5 Illq 0.22 0.67 7.6 1.12 5 Illr 1.00 0.35 7.6 2.66 5 IVa 1.95 0.46 7.6 6.82 5 IVb 2.97 0.37 7.6 8.35 5 IVc 7.48 0.35 7.6 19.90 6 IVd 1.54 0.36 7.6 4.21 - Total 39.63 - 7.6 115.67 Runoff Computations 10-Year Storm • • Stocks Engineering, P.A. 1100 Eastern Avenue PO Box 1108 Nashville, NC 27856 • rost- uevelopm ent 5 la 0.10 0.67 8.6 0.58 5 Ib 0.44 0.62 8.6 2.35 5 Ila 4.94 0.35 8.6 14.87 5 Illa 2.14 0.36 8.6 6.63 5 Illb 0.38 0.43 8.6 1.41 5 Illc 0.62 0.67 8.6 3.57 5 Illd 1.1 0.67 8.6 6.34 5 Ille 0.33 0.43 8.6 1.22 5 Illf 0.15 0.67 8.6 0.86 5 Illg 1.02 0.35 8.6 3.07 5 Illh 5.67 0.35 8.6 17.07 5 Illi 6.38 0.35 8.6 19.20 5 Illj 0.27 0.67 8.6 1.56 5 Illk 0.11 0.67 8.6 0.63 5 IIII 0.16 0.47 8.6 0.65 5 Illm 1.00 0.39 8.6 3.35 5 Illn 0.30 0.35 8.6 0.90 5 Illo 0.34 0.35 8.6 1.02 5 Illp 0.46 0.42 8.6 1.66 5 Illq 0.22 0.67 8.6 1.27 5 Illr 1.00 0.35 8.6 3.01 5 IVa 1.95 0.46 8.6 7.71 5 IVb 2.97 0.37 8.6 9.45 5 IVc 7.48 0.35 8.6 22.51 6 IVd 1.54 0.36 8.6 4.77 - Total 39.53 - 8.6 130.89 Runoff Computations 25-Year Storm • • Stocks Engineering, P.A. 1100 Eastern Avenue PO Box 1108 Nashville, NC 27856 Post-Development 5 la 0.10 0.67 10 0.67 5 Ib 0.44 0.62 10 2.73 5 Ila 4.94 0.35 10 17.29 5 Illa 2.14 0.36 10 7.70 5 Illb 0.38 0.43 10 1.63 5 Illc 0.62 0.67 10 4.15 5 Illd 1.1 0.67 10 7.37 5 Ille 0.33 0.43 10 1.42 5 Illf 0.15 0.67 10 1.01 5 Illg 1.02 0.35 10 3.57 5 Illh 5.67 0.35 10 19.85 5 Illi 6.38 0.35 10 22.33 5 Illj 0.27 0.67 10 1.81 5 Illk 0.11 0.67 10 0.74 5 IIII 0.16 0.47 10 0.75 5 Illm 1.00 0.39 10 3.90 5 Illn 0.30 0.35 10 1.05 5 Illo 0.34 0.35 10 1.19 5 Illp 0.46 0.42 10 1.93 5 Illq 0.22 0.67 10 1.47 5 Illr 1.00 0.35 10 3.50 5 IVa 1.95 0.46 10 8.97 5 IVb 2.97 0.37 10 10.99 5 IVc 7.48 0.35 10 26.18 6 IVd 1.54 0.36 10 5.54 - Total 39.53 - 10.0 152.20 Runoff Computations 100-Year Storm • rfc~4~ F~ ~,.~ Cj-c. c S • PCt~. Dcu~~o?t~k ~T Gu~ti/w.~ ~~ Sd . $ ~ A L x '7 I '~ 5'a . 8 cQ A-c G~ = '7 I ?moo S i 'Drr v F.~.w° w•a.~...:( 7 ,_~ -~ /MtE2.rtrsv S (8.3 o g c k 9 8~ -~ ~ 3 ~. S8 q c k (~ I) -~ (!-f . ~~ a c k ss~ '/. Ste. $ C ~c • ~~= c~~.s • Table 3.3 Runoff Curve Numbers1 • • Cover Descri tion ~ Curve Numbers for H drolo is Soil Grou s Cover type and i~drolo~ic condition A B C D Cultivated land: --_ _ __ _. without conservation treatment 72 y 81 88 91 with conservation treatment 62 71 78 81 Pasture or range land poor condition 68 79 86 89 good condition 39 61 74 80 Meadow: good condition 30 58 71 78 Wood or forest land: thin stand, poor cover 45 66 77 83 good cover 25 55 70 77 open Space (lawns, parks, golf courses, cemeteries, etc.) 2 Poor condition (grass cover <50%) 68 79 86 89 Fair condition (grass cover 50% - 75%) 49 69 79 84 Good condition (grass cover >75%) 39 61 74 80 Impervious areas: Paved parking lots, roofs, driveways, etc. g8 98 98 98 (excluding right-of-way) Streets and Roads: Paved; curbs and storm drains (excluding right- of-way) 98 98 98 98 Paved; open ditches (including right-of-way) 83 89 92 93 Gravel (including right-of-way) 76 85 89 91 Dirt (including right-of-way) 72 82 87 89 Developing urban areas and newly graded 77 86 91 94 areas (pervious area only, no vegetation) Urban districts by zoning: O& I and all B-Zones 96 97 98 98 Industrial Zones 98 98 98 98 Commercial/Shopping Centers Residential districts by zoning: R-15, very low density 61 75 83 87 R-10. low density 61 75 83 87 R-8, manufactured 71 80 87 92 R-6, single family 71 80 87 92 R-6MFA, medium density multi-family 80 85 90 95 MFA, multi-family 86 90 93 96 MHP, mobile home park 92 94 96 97 ~ Average runoff condition, and la = 0.2S 2 CNs shown are equivalent to those of pasture. Composite CNs may be computed for other combinations of open space cover type. Assumptions are as follows: impervious areas are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open space in good hyd rologic condition. If the impervious area is not co nnected, the NRCS method has an ad'ustment to reduce the effect. Gity of Rocky Mounf Stormwater Design Manual December 2006 3-7 Hydrograph Return Period Recap Hydraflow Hydrographs by Intelisolve v9.22 • • • Hyd. N Hydrograph Inflow Peak Outflow (cfs) Hydrograph o. type (origin) Hyd(s) 1-Yr 2-Yr 3-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr description 1 2 SCS Runoff SCS Runoff ------- ------- 39.25 26.70 ------- ------- ------- ------- ------- ------- 113.47 93.53 162.23 138.68 ------- ------- 226.80 200.41 Pre Devleopment Post Develpment Proj. file: Pre vs Post.gpw Tuesday, Mar 18, 2008 Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.22 • • Hyd No. . Hydrograph type (origin) Peak flow (cfs) Time interval (min) Time to peak (min) Hyd. volume (tuft) Inflow hyd(s) Maximum elevation (ft) Total strge used (tuft) Hydrograph description 1 SCS Runoff 39.25 2 730 159,582 ---- ------ ------ Pre Devleopment 2 SCS Runoff 26.70 2 730 120,819 ---- ------ ------ Post Develpment Pre vs Post.gpw Return Period: 1 Year Tuesday, Mar 18, 2008 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.22 Hyd. No. 1 Pre Devleopment Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 3.20 in Storm duration = 24 hrs 3 Tuesday, Mar 18, 2008 Peak discharge = 39.25 cfs Time to peak = 730 min Hyd. volume = 159,582 cult Curve number = 71 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Q (cfs) 40.00 i 30.00 Pre Devleopment Hyd. No. 1 -- 1 Year 20.00 10.00 0.00 I~~ Q (cfs) 40.00 30.00 20.00 10.00 0 00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 . Time (min) Hyd No. 1 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.22 Hyd. No. 2 Post Develpment Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 3.20 in Storm duration = 24 hrs 4 Tuesday, Mar 18, 2008 Peak discharge = 26.70 cfs Time to peak = 730 min Hyd. volume = 120,819 cult Curve number = 66.5 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Post Develpment Q (cfs) Hyd. No. 2 -- 1 Year Q (cfs) 28.00 • 24.00 20.00 16.00 12.00 8.00 4.00 0.00 28.00 24.00 20.00 16.00 12.00 8.00 4.00 0 00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 S Time (min) Hyd No. 2 Hydrograph Summary Report HydraflowHydrographsbylntelisolvev9.22 • I Hyd. No. Hydrograph type (origin) Peak flow (cfs) Time interval (min) Time to peak (min) Hyd. volume (cult) Inflow hyd(s) Maximum elevation (ft) Total strge used (cult) Hydrograph description 1 SCS Runoff 113.47 2 728 423,518 ---- ------ ------ Pre Devleopment 2 i SCS Runoff 93.53 2 730 356,329 ---- ------ ------ Post Develpment Pre vs Post.gpw Return Period: 10 Year Tuesday, Mar 18, 2008 Hydrograph Report s Hydraflow Hydrographs by Intelisolve v9.22 Hyd. No. 1 Pre Devleopment Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 5.28 in Storm duration = 24 hrs Tuesday, Mar 18, 2008 Peak discharge = 113.47 cfs Time to peak = 728 min Hyd. volume = 423,518 cuft Curve number = 71 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Q (cfs) 120.00 100.00 80.00 60.00 40.00 - 20.00 - • Q (cfs) 120.00 100.00 80.00 60.00 40.00 20.00 0.00 -~ ~ ~ ~ ~ _~- i i i i i i ~ ~ 0.00 0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560 Hyd No. 1 Time (min) Pre Devleopment Hyd. No. 1 -- 10 Year Hydrograph Report 7 Hydraflow Hydrographs by Intelisolve v9.22 . Hyd. No. 2 Post Develpment Hydrograph type = SCS Runoff Storm frequency = 10 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 5.28 in Storm duration = 24 hrs Tuesday, Mar 18, 2008 Peak discharge = 93.53 cfs Time to peak = 730 min Hyd. volume = 356,329 cuft Curve number = 66.5 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Q (cfs) 100.00 90.00 80.00 70.00 60.00 50.00 40.00 - 30.00 - 20.00 - 10.00 - 0.00 -' ' 0 120 240 • Hyd No. 2 Post Develpment Hyd. No. 2 -- 10 Year 360 480 600 720 Q (cfs) 100.00 90.00 80.00 70.00 60.00 50.00 40.00 30.00 20.00 10.00 ...~..a_ 0.00 840 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Summary Report HydraflowHydrographsbylntelisolvev9.22 Hyd ' No. . Hydrograph type (origin) Peak flow (cfs) Time Interval (min) Time to peak (min) Hyd. volume (cult) Inflow hyd(s) Maximum elevation (ft) Total strge used (cult) Hydrograph description 1 SCS Runoff 162.23 2 728 597,935 ---- ------ ------ Pre Devleopment 2 SCS Runoff 138.68 2 728 517,853 ---- ------ ------ Post Develpment Pre vs Post.gpw Return Period: 25 Year Tuesday, Mar 18, 2008 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.22 • Hyd. No. 1 Pre Devleopment Hydrograph type = SCS Runoff Storm frequency = 25 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 6.48 in Storm duration = 24 hrs Q (cfs) 180.00 • 160.00 140.00 120.00 100.00 80.00 - 60.00 - 40.00 - 20.00 - 0.00 -' ' 0 120 240 • Hyd No. 1 9 Tuesday, Mar 18, 2008 Peak discharge = 162.23 cfs Time to peak = 728 min Hyd. volume = 597,935 cuft Curve number = 71 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Pre Devleopment Hyd. No. 1 -- 25 Year 360 480 600 720 840 Q (cfs) 180.00 160.00 140.00 120.00 100.00 80.00 60.00 40.00 20.00 ~~.,,_,,..~_ 0.00 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Report 10 Hydraflow Hydrographs by Intelisolve v9.22 Hyd. No. 2 Post Develpment Hydrograph type = SCS Runoff Storm frequency = 25 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 6.48 in Storm duration = 24 hrs Tuesday, Mar 18, 2008 Peak discharge = 138.68 cfs Time to peak = 728 min Hyd. volume = 517,853 cult Curve number = 66.5 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Q (cfs) 140.00 • 120.00 100.00 - 80.00 - 60.00 - 40.00 - 20.00 - 0.00 -~ y , 0 120 240 • Hyd No. 2 Post Develpment Hyd. No. 2 -- 25 Year 360 480 600 720 Q (cfs) 140.00 120.00 100.00 80.00 60.00 40.00 20.00 _~ ~ ~ ~ ~ ~..~.,.:_ 0.00 840 960 1080 1200 1320 1440 1560 Time (min) 11 Hydrograph Summary Report Hydraflow Hydrographs by intelisolve v9.22 ' Hyd No. . Hydrograph type (origin) Peak flow (cfs) Tlme interval (min) Tlme to peak (min) Hyd. volume (cult) Inflow hyd(s) Maximum elevation (ft) Total strge used (cult) Hydrograph description 1 SCS Runoff 226.80 2 728 832,214 ---- ------ ------ Pre Devleopment 2 SCS Runoff 200.41 2 728 738,648 ---- ------ ------ Post Develpment Pre vs Post.gpw Return Period: 100 Year Tuesday, Mar 18, 2008 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.22 • Hyd. No. 1 Pre Devleopment Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 8.00 in Storm duration = 24 hrs Pre Devleopment Q (cfs) Hyd. No. 1 -- 100 Year 240.00 • 210.00 180.00 _ 150.00 120.00 _ __ 90.00 60.00 30.00 0.00 -` ' 0 120 240 • Hyd. No. 1 12 Tuesday, Mar 18, 2008 Peak discharge = 226.80 cfs Time to peak = 728 min Hyd. volume = 832,214 cult Curve number = 71 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 Q (cfs) 240.00 210.00 180.00 150.00 120.00 90.00 60.00 30.00 .~ _._.~. ~ ~ ~ ~ ~ ~ _- ~_ 0.00 360 480 600 720 840 960 1080 1200 1320 1440 1560 Time (min) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.22 • Hyd. No. 2 Post Develpment Hydrograph type = SCS Runoff Storm frequency = 100 yrs Time interval = 2 min Drainage area = 50.860 ac Basin Slope = 1.0 Tc method = KIRPICH Total precip. = 8.00 in Storm duration = 24 hrs Q (cfs) 210.00 • 180.00 150.00 - 120.00 - 90.00 - 60.00 - 30.00 - Tuesday, Mar 18, 2008 Peak discharge = 200.41 cfs Time to peak = 728 min Hyd. volume = 738,648 cuft Curve number = 66.5 Hydraulic length = 3600 ft Time of conc. (Tc) = 25.14 min Distribution = Type II Shape factor = 484 13 Post Develpment Hyd. No. 2 -- 100 Year 0.00 -I ~ ~ ~ ~ ____.-•'- i i 0 120 240 360 480 600 720 840 • Hyd No. 2 Q (cfs) 210.00 180.00 150.00 120.00 90.00 60.00 30.00 ' '- 0.00 960 1080 1200 1320 1440 1560 Time (min) • • Tar-Pamlico Stormater Rule 15A NCAC 28 .0258 Last Modified 4/7/2008 Residential Worksheet when Footprints are not Shown Ilse this worksheet when building footprints are not known to determine the acreage in each of the four categories - transportation impervious, roof impervious, managed pervious, and wooded pervious - in the development. You will need these acreages for both the "Export before BMPs" and "Export after BMPs" worksheets. For the "Export after BMPs" worksheet, you will need to subtract the acreage occupied by BMPs from the managed envious acreage produced by this worksheet. Also for the "Export after BMPs" worksheet, if the development contains more than one catchment, use this worksheet for each catchment. Project Name: W'ornhle Farms Phase 3 Date: 3/18/20078 By: 1-. I' arnell Directions: > In the two green spaces in the box below, enter the average lot size and the percent of the right-of--way that is impervious within the development. > In the table below, for the type of land cover listed for each column, enter acreages in the green boxes beneath. > In the "Lot Area" column, be sure to enter acreage within lots that is protected by a conservation easement, the Tar- Pamlico buffer rule, or wetland rules in the green box in the lower lefthand corner (enter "0" if there is none). If lots are drawn to exclude protected lands that are part of the total development acreage, enter the acreage of those protected lands as wooded pervious in the "Community Areas" column. > The spreadsheet will compute all values in the light blue shaded boxes. > NOTE: In the "Community Areas" column, you will need to ensure that the various component acreages sum to the value in the "TOTAL" box at the top. The spreadsheet will not correct for inconsistencies. Any inconsistency between the total value and the sum of individual acreages will carry over to column (5). Average lot size - 1.14 ac (Must show building footprints if lot size < 0.13 ac.) impervious in right-of--way 33 Type of Iatad Cover Lot area Right-of-way area.: Ccrmmunrty areas S~iri~ of Colu~r~s .; TUTA[~.:.... ; 1.4 52.2 Transportation impervious '. 3.8 1.8 5.6 Raol' impervious 2.5 2.5 Managed pervi~rus 34.1 3.7 37.7 V1'QOded pervious 5.0 6.4 Tar-Pamlico Stormwater Rule 15A NCAC 28.0258 Piedmont of the Tar-Pamlico River Basin: • • Last Modified 4/7/2008 Includes Oxford, Henderson, Rocky Mount and Tarboro as well as Franklin, Nash and Edgecome Counties Total Nitrogen and Total Phosphorus Loading Calculation Worksheet (Automated) Project Name: {/'orrTble l arnrc Pb~r.+e 3 Date: 3/18/2008 By: K. Vnrrrell Checked By: Directions (same for pre-development and post-development tables): > Enter the acres of each type of land cover in the green boxes. The spreadsheet will calculate all of the values in light blue. > Compare total areas of development in pre- and post- tables for consistency (bottom of column (2)), and also for consistency with the site plans. If all of these values are not the same, there is an error that must be corrected. > Unless drainage onto the development from offsite is diverted around or through the site, offsite catchment area draini ng in must be included in the acreage values and treated. Pre-development: ,. ,. .... 'H`ype of iraad Cover Area S.M. liormula Average I~MC Colvrng average EMC Calumn acres 446:+8.3I ' vf'lrkVi 2 ~:3 * oll`I'P;m L 2 * 3:a 6 Trait&jioiYatl4l~ impervious `''~ 0.46 2.60 0.00 0.19 0.00 RaofimpGrvaus 0.46 1.95 0.00 0.11 0.00 Managed pervious 0 46 1.42 0.00 0.28 0.00 . (~aw~Ilans'~sea~d~:..: . ...................:............. . Managed prrrfiQUS (cropland)::.. - 0.46 4.23 101.63 1.23 29.55 Man~ged psrviois'" tpastgre}: 0.46 2.04 0.00 0.62 0.00 Wooded pervious ...:::.:: 0.46 0.94 0.00 0.14 0.00 Fi•actian Impervious (I) 0.00 T1Y Laadirig 101.63 TP laadzng 29.55 Total Area of 1;Ievielopment = ' 52.23 TN Exp Crreff c/ Ibt r) ` 1.95 TP Exp Coe . lael r ,: l 0.57 . ( a y ::: b y } f Post-development: Type o€ Laad Cover Area S M IFormula Average EMS Columu ; Average EMC: C~rlumn ::acres !! 0:4b+ 8 31 ; of TI~I m G 2 k: 3 x d of TP:m G : 2 ~ ~ 6 TCai#spoaf~ivn;imperw'ious;:;:; 5.6 1.75 2.60 25.50 0.19 1.86 Rool'iiipervious 2.5 1.75 1.95 8.59 0.11 0.48 l~fana~±er~pervivus 37.7 1.75 1.42 93.86 0.28 18.51 VVoiilc±~ ~ie'~i±~us 6.4 1.75 0.95 10.60 0.14 1.56 Martian !m rviaus pe (1) 0.16 TI?~ L~oad~rg 138 54 TP Loading 22.42 Tatal:Area AfllevellEipine~if.'.: 52.23 TN E.xp Corfu 2.65 TP Exp. Coeff 0.43 (.lbiac/yr) (Iblarlyr) • Note: The nutrient loading goals are 4.0 lb/ac/yr for TN and 0.4 Ib/ac/yr for TP. If the post-development nutrient loading is below these levels, then no BMP is necessary. Otherwise, the next worksheet calculates post-development TN and TP loadings after BMPs are installed. Tar-Pamlico Stormwater Rule 15A NCAC 28 .0258 Piedmont of the Tar-Pamlico River Basin: Last Modified 5/23/03 tnctutles uxtortl, Hentlerson, Kocky Mount and 1 arboro as well as Franklin, Nash and Edgecome Counties • • • BMP Removal Calculation Worksheet (Automated) Project Name: N'uuthh~ Fnrnts Pliusr .; Date: 3/18/?t708 By: ti. b'arnell Checked By: > It may be advantageous to split the development into separate catchments to be handled by separate BMPs. The tables below allow the development to be split into as many as three catchments, and can be copied for greater than three. NOTE: Unless runoff flowing onto the development from offsite is routed separately around or through the site, the offsite catchment area draining in must be included in the acreage values of the appropriate land use(s) and treated. > Above each table: Enter the catchment acreage in the top green blank. Based on a comparison of the post-development TN and TP export coefficients you calculated above to the rule requirements of 4.0 Ib/ac/yr TN and 0.4 Ib/ac/yr TP, select BMP(s) from the list for treating the catchment runoff Enter the chosen BMP(s) nutrient removal rates in the green blanks. if more than one BMP is to be used in series, the combined removal rates will be calculated automatically in the blue blanks. > Catchment Tables: Enter the acres of each type of land cover in the green boxes. The spreadsheet will calculate all of the light blue boxes. NOTE: Compare the Total Catchment Acreage for the Development (tinal table) to the value you established in the pre-BMP worksheet tables, and also to the site plans, for consistency. All of these values need to be the same T~ TI? bes~~n ~tandar~: BMP Wetl)eteatiou Pond 25 40 NC BMP Manual Nutrient ' 4tgrmwater Wetland 40 35 NC BMP Manual Removal 3aad Ftlter 35 45 NC BMP Manual Rates Blore#entio>z; 35 45 NC BMP Manual G>•ass Sn'~e: 20 20 NC BMP Manual Uegetatcti Ft(#er~#np wr( 20 35 NC BMP Manual ;:Level Spreade>r;:;:::;:;: ~eyE)etehlloil ' ' 10 10 NC BMP Manual ........................ Catchment 1: Total acreage of catchment I = 52.23 ac First BMP's TN removal rate = 0 ~~ First BMP's TP removal rate 0 `% Second BMP's TN removal rate = 0 ~~ Second BMP's TP removal rate 0 '% Third BMP's TN removal rate = ~ `%o Third BMP's TP removal rate TOTAL TN REMOVAL RATE = 0 % TOTAL TP REMOVAL RA'fL 11 '„ roq o:~:~ ~- .wva: ^ :~ ~aac 1 . .~ , .n,.J .n. M : . ~ :R ~ :R: n' Transpgrtationumperviope 5.6 1.75 2.60 25.50 0.19 1.86 Roof impervrous 2.5 1.75 1.95 8.59 U.l l 0.48 I1~anaged pietvtgas 37.7 1.75 1.42 93.86 0.28 18.51 Wooded }iervtaas 6.4 1.75 0.94 10.49 0.14 1.56 Arestakenitpliy~(~P; ; ;; : 1.75 1.95 0.00 0.11 O.OU praet[crn Impevtou@ f T)a 0.16 Pre-BMP 1`N 138.43 1're-BMP m 22 42 Load (Ib/yr).~ Load (1Eilyt): . Total Area of 1)evelop~t>nt 52.23 Pro-BNtl TN 2.65 #'re B1191'T,. 0 43 Export h~/ac/yr} ~ .f>rpart (lblacFyti:. . Post-BIkIP'1'N Post BMP TP Load (Itilyr) 138.43 Load (tblyt!) 22.42 Wlsx BMPT 2.65 -:Post-SMYT~ 0 43 Export (IhFarlyr} : gxpuR Ob/ac/yrj:: . • Tar-Pamlico Stormwater Rule 15A NCAC 28 .0258 Last Modified 5/23/03 Catchment 2: Total acreage of catchment 2 = ~ ac First BMP's TN removal rate „ First BMP's TP removal rate = Second BMP's TN removal rate Second BMP's TP removal rate = Third BMP's TN removal rate = "~,~ Third BMP's TP removal rate = TOTAL TN REMOVAL RATF_, = 0 %n TOTAL TP REMOVAL RATE = 0 Type of Land Govcr C'atchm@n.t S.N#. Fgrmula Average EMCp CbluatYiii Aver~agq E1VI~ o Column Aereaae (0.4fi + $i33) TAf fmi;rlL1 a21 ~L31 x[41 TP (mni1.5 i2i rill r «i runaportatwn: ~npervtous;:: 2.60 0.19 Rpgf iirip@wabu~:.;'::.:.:. ',' 1.95 11 0 . l~arii)geii pervious ;:;;;!; i' ' 1.42 0.28 Wooded ~1erNaR.S 0.94 0.14 Area:taken..up by;l3MF:::::: 1.95 0.11 Fraction Impervious (~) Are-BN1P'C1V Pre-BI1~P:TP Load (Ib/yrj = Lbntl (Iblyi!): Tdt01 f1re8~ of Develop~t ~ 0.00 Pr¢-BMA TiV Bxpari Pre-I3MP TP Ezpo. Font BMPTN :Post-BI1#R TR l.oad;flb/yr) = Ivad ()lilyr) ~l'oxY90.1P7'.~ Post-BMP3'PEx~tii~ .i~ ~' i .:i~ is . .~i 7`ixpOrt (IbfacJyrj:: Ilblac(y l-1. • Catchment 3: Total acreage of catchment 3 = uc First BMP's TN removal rate = ' <~ First BMP's TP removal rate '% Second BMP s TN removal rate = ,~ Second BMP's TP removal rate % Third BMP's TN removal rate = 4;, Third BMP's TP removal rate TOTAL TN REMOVAL RATE = 0 % TOTAL TP REMOVAL RATL = 0 Typet+iLsnd Dover iittehmerit: ' 5,114. Formula Average:EMC b Coluiun Average EMCo [;olusich.:: re e. 46+ 3 1 . TN m L ~ - 3 .R: ~ ~~ m L 2 ~: 3 ~' 6 "~ranspoftsfpon ~nipervoua,l - 2.60 0.19 R.ootii[pervio.us . ;..... 1.95 0.11 Managed:ge3'du+ss; : _ . ,' 1.42 0.28 Wooded pervloiis 0.94 0.14 Area taken up by 8MP 1.95 0.11 Fraction Imperv~qus ()I)= Pre 13MP1'1V Pre BMP 7' Logd tllt/}!r) = Liiad;(lfilyr) Total area bf Ilevelophie8t Pre.B3N~9`~I E'xpa; Pre.~Mt' Tp kzpq ; (Ibfar.Jyr),: ttb/aclytj:. Post-SlY1PT1Y Posf BPV~P'CP 40ad (141YC). Load (IbfvNl ' • • • Tar-Pamlico Stormwater Rule 15A NCAC 28.0258 Last Modified 5/23/03 • • NUTRIENT OFFSET MITIGATION PAYMENT SUMMARY • Jurisdiction: Rocky Mount Basin: Tar/Pamlico Project Name: Womble Farms Phase 3 Address: Beulah Road Engineer of Record: Stocks Engineering Date: 3/18/08 Site Characteristics Acreage 52.23 acres Redevelopment Site: No (Yes or No) BMP(s) Utilized: None Pre-Develo ment Nitro en and Phos horous Loadin Nitrogen 101.63 Ib/year 1.95 Ib/acre/year Phosphorous 29.55 0.11b/year 0.57 0.11b/acre/year Post-Develo ment Nitro en and Phos horous Loadin Nitrogen 138.54 Ib/year 2.65 Ib/acre/year Phosphorous 22.42 0.11b/year 0.43 0.11b/acre/year Nitro en and Phos horous Loadin Limits Nitrogen 208.92 Ib/year 4.00 Ib/acre/year Phosphorous 20.892 0.11b/year 0.40 0.11b/acre/year Note: If Redevelopment Site, limits are based on 30% reduction in Nitrogen and pre-development loading for Phosphorous Post-BMP Nitro en and Phos horous Loadin Nitrogen 138.43 Ib/year 2.65 Ib/acre/year Phosphorous 22.42 0.11b/year 0.43 0.11b/acre/year Note: Unless project is a redevelopment site, post Nitrogen loading is subject to 6 (or 10) Ibs/acretyear threshold Nutrient Bu -Down Summa Nitrogen = -70.49 Ib/year -1.35 Ib/acre/year Phosphorous = 1.52 0.1 Ib/year 0.03 0.1 Ib/acre/year NCEEP Offset Pa ment Schedule Nitrogen = $21.67 per Ib. Phosphorous = $28.62 per 0.1 Ib. Land cost tax value = N/A total N/A er acre Bu down Calculations Nitrogen _ [($ /Ib) (# of Ib/yr) (30 yrs) Total Nitrogen Buydown $ - Phosphorous _ [($ /0.1 Ib) (# of 0.1 Ib/yr) (30 yrs) Total Phosphorus Buydowi $ 13,092.35 Total Nutrient Offset Miti ation Pa ment = $13,092.35 (Note: Miti ation Pa ment is rester of the two fees between Nitro en and Phosphorous) • • Hydro.low Plan View • • Outfall Project File: FES 5 to FES 6.stm ~ No. Lines: 1 ~ 03-20-2008 Hydraflow Storm Sewers 2005 Stogy Sewer Inventory Report ~ Page 1 Line Alignment Flow Data Physical Data Line ID No. Dnstr Line Defl Junc Known Drng Runoff Inlet Invert Line Invert Line Line N J-loss Inlet/ line length angle type Q area cceff time EI Dn slope EI Up size type value cceff Rim EI No. (ft) (deg) (cfs) (ac) (C) (min) (ft) (%) (ft) (in) (n) (K) (ft) 1 End 56.0 0.4 Hdwl 14.87 0.00 0.00 0.0 177.50 3.13 179.25 18 Cir 0.013 1.00 183.87 FES5 to FES6 Project File: FES 5 to FES 6.stm Number of lines: 1 Date: 03-20-2008 Hydraflow Storm Sewers 2005 • • • Storm Sewer Summary Report Page 1 Line No. Line ID Flow rate (cfs) Line size (1n) Line length (ft) Invert EL Dn (ft) Invert EL Up (ft) Line slope (%) HGL down (ft) HGL up (ft) Minor loss (ft) HGL Junct (ft) Dns line No. 1 FES5 to FES6 14.87 18 c 56.0 177.50 179.25 3.125 178.90 180.65 n/a 180.65 End Project File: FES 5 to FES 6.stm Number of lines: 1 Run Date: 03-20-2008 NOTES: c = cir; e = ellip; b =box; Return period = 25 Yrs. Hydraflow Storm Sewers 2005 Hyd~ilic Grade Line Computations ~ • Page 1 Line Size Q Downstream Len Upstream Check JL Minor in) cfs) Invert elev (ft) HGL elev (ft) Depth (ft) Area (sgft) Vel (ft/s) Vel head (ft) EGL elev (ft) Sf (%) ft) Invert elev (ft) HGL elev (ft) Depth (ft) Area (sgft) Vel (ft/s) Vel head (ft) EGL elev (ft) Sf (%) Ave Sf (%) Enrgy loss (ft) coeff (K) loss (ft) 1 18 14.87 177.50 178.90 1.40 1.72 8.65 1.16 180.07 1.733 56.0 179.25 180.65 1.40" 1.72 8.65 1.16 181.82 1.733 1.733 n/a 1.00 n/a Project File: FES 5 to FES 6.stm Number of lines: 1 Run Date: 03-20-2008 Notes: ; "Critical depth. Hydraflow Storrs Sewers 2005 Stun Sewer Profile • Proi filP• FF'~ FFS R Elev. (ft 203.00 197.00 191.00 185.00 179.00 173.00 0 203.00 197.00 191.00 185.00 179.00 I 173.00 10 20 30 40 50 60 70 80 90 100 Reach (ft) Hydraflow Storm Sewers 2005 7 _ r .. ~ H dr~ow P y Ian View Outfall Project file: FES 8 to FES 9.stm No. Lines: 1 03-12-2008 HydraFlow Storm Sewers 2003 • • • Storm Sewer Summary Report Page 1 Line Line ID Flow Line Line Invert Invert Line HGL HGL Mlnor Dns No. rate size length EL Dn EL Up slope down up loss line (cfs) (in) (ft) (ft) (ft) (%) (ft) (ft) (ft) No. 1 FESB to FES9 8.04 18 c 64.0 177.32 177.64 0.500 178.82' 179.20' 0.32 End Project File: FES 8 to FES 9.stm Number of lines: 1 Run Date: 03-12-2008 NOTES: c =circular; a =elliptical; b =box; Return period = 25 Yrs.; * Indicates surcharge condition. Hydraflow Storm Sewers 2003 Hyd~.~lic Grade Line Computations ~ • Page 1 Line Size Q Downstream Len Upstream Check JL Minor in) cam) Invert elev (ft) HGL elev (ft) Depth (ff) Area lsgft) Vel (~s1 Vel head 1ft1 EGL elev (ft) Sf (°/a) ft) Invert elev (n) HGL elev (ft) Depth (ft) Area (Sqn) Vel (ft/s) Vel head (ft1 EGL elev (ft) Sf (%) Ave Sf (%) Enrgy loss (ft) coeff (K1 loss (ft) 1 18 8.04 177.32 178.82 1.50 1.77 4.55 0.32 179.14 0.586 64.0 177.64 179.20 1.50 1.77 4.55 0.32 179.52 0.586 0.586 0.375 1.00 0.32 'i I Project File: FES 8 to FES 9.stm Number of lines: 1 Run Date: 03-12-2008 NOTES: `Normal depth assumed., "Critical depth assumed. - Hydraflow Storm Sewers 2003 Stc~ Sewer Profile • Proi. file: FES•FFS 9 ctm Elev. (ft) 198.00 193.00 188.00 183.00 178.00 173.00 0 10 20 30 40 50 60 70 80 90 100 Reach (ft) Hydraflow Storm Sewers 2003 • Hydrdrlow Plan View • • Hydraflow Slorm Sewers 2003 • • • Storm Sewer Summary Report Page 1 Line Line ID Flow Line Line Invert Invert Line HGL HGL Minor Dns No. rate size length EL Dn EL Up slope down up loss line (cfs) (in) (ft) (ft) (ft) (%) (ft) (ft) (ft) No. 1 FES10 to FES11 70.41 42 c 44.0 167.50 167.72 0.500 170.34 170.56 1.10 End Project File: FES 10 to FES 11.stm Number of lines: 1 Run Date: 03-12-2008 NOTES: c =circular; a =elliptical; b =box; Return period = 25 Yrs.; * Indicates surcharge condition. Hydraflow Storm Sewers 2003 Hyd~,alic Grade Line Computations ~ • Page 1 Line Size Q Downstream Len Upstream Check JL Minor' n1 cam) Invert elev (ft) HGL elev (ft) Depth (ft) Area (sgft) Vei (ws) Vel head (ft) EGL elev (ff) Sf (%) ft) Invert elev (ff) HGL elev (ft) Depth (ft1 Area (Sgft) Vel (mss) Vel head (ft) EGL elev (ftl Sf (%) Ave Sf (%) Enrgy loss (ft) coeff (K) loss (ft) 1 I 42 70.41 167.50 170.34 2.84 8.37 8.41 1.10 171.44 0.498 44.0 167.72 170.56 2.84 8.36 8.42 1.10 171.66 0.499 0.498 0.219 1.00 1.10 Project File: FES 10 to FES 11.stm Number of lines: 1 Run Date: 03-12-2008 NOTES: 'Normal depth assumed., ** Critical depth assumed. Hydraflow Storm Sewers 2003 Std~r~ Sewer Profile • Proj. file: FES 1~ES 11.stm Elev. (ft) 193.00 187.00 Reach (ft) Hydraflow Storm Sewers 2003 Hydraflow Storm Sewers 2003 H dr y ow Plan View • • • Storm Sewer Summary Report Page 1 Line Line ID Flow Llne Line Invert Invert Line HGL HGL Minor Dns No. rate size length EL Dn EL Up slope down up loss line (cfs) (in) (ft) (ft) (ft) (%) (ft) (ft) (ft) No. 1 FES19 to FES22 2.19 18 c 44.0 166.48 166.70 0.500 167.04 167.27 0.20 End Project File: FES 19 to FES 22.stm Number of lines: 1 Run Date: 03-12-2008 NOTES: c =circular; a =elliptical; b =box; Return period = 25 Yrs.; * Indicates surcharge condition. Hydraflow Slorm Sewers 2003 Hyd~ulic Grade Line Computations ~ • Page 1 Line Size Q Downstream Len Upstream Check JL Minor (in) (°~) Invert elev (ft) HGL elev (ft) Depth (ft) Area (soft) Vel (mss) Vel head (ft) EGL elev (ft) Sf (%) (~) Invert elev (ft) HGL elev (ft) Depth (n) Area (soft) Vel (mss) Vel head (ft) EGL elev (ft) Sf (%) Ave Sf (%) Enrgy loss (ft) coeff (K) loss (ft) 1 18 2.19 166.48 167.04 0.56 0.61 3.60 0.20 167.25 0.479 44.0 166.70 167.27 0.57 0.61 3.57 0.20 167.47 0.467 0.473 0.208 1.00 0.20 Project File: FES 19 to FES 22.stm Number of lines: 1 Run Date: 03-12-2008 NOTES: 'Normal depth assumed., ** Critical depth assumed. Hydraflow Storm Sewers 2003 Stc~ Sewer Profile • Proj. file: FES 1:~ES 22.stm Elev. (ft) 188 00 . 83 00 __ _ _ _ _ - - _ __ __ - . 178.00 __ _ _ _. __ _ _ - FES19 t FES22 ___ _ Rim:.. 1.6 ,37 ({~) _ _ _ _ __ -- - -- -- -- - tJp-Inv: f6-70-(ft - - - - _-- Dn fnv:_ 66:48_ (ft) _ _ _ __ 173.00 en: _ 18 ('in) __ _ _. 68 00 _ __ _ __ __ -_ - _. . _ _ _ _ _ _ _ __ __ __ 163.00 __ 0 10 20 30 40 50 60 70 80 90 100 Reach (ft) Hydraflow Storm Sewers 2003 • • Womble Farms Subdivision Ditch Sections Ditch Section Side Sio Channel Slo Q,o ~~~ Proposed Limn Mannings n Normal De th V~D ~a Calculated Shear Ib! LinedStable 2 TO 3 4:1 0.50% 2.58 Bare Ground 0.020 0.51 2.52 0.16 Needs Ve Vegetation 0.035 0.62 1.65 0.19 Stable 4 TO 2 4:1 0.50% 2.07 Bare Ground 0.020 0.47 2.38 0.15 Needs Ve Vegetation 0.035 0.58 1.56 0.18 Stable 4 TO 1 4:1 0.50% 0.51 Bare Ground 0.020 0.28 1.68 0.09 Needs Ve Vegetation 0.035 0.34 1.10 0.11 Stable 7 TO 11 4:1 0.50% 5.60 Bare Ground 0.020 0.68 3.05 0.21 Needs Ve Vegetation 0.035 0.84 2.01 0.26 Stable 7 TO 8 4:1 0.50% 5.86 Bare Ground 0.020 0.69 3.09 0.21 Needs Ve Vegetation 0.035 0.85 2.03 0.27 Stable 14 TO 8 4:1 0.50% 1.24 Bare Ground 0.020 0.38 2.09 0.12 Needs Ve Vegetation 0.035 0.47 1.38 0.15 Stable 13 TO 9 4:1 0.50% 3.16 Bare Ground 0.020 0.55 2.65 0.17 Needs Ve Vegetation 0.035 0.67 1.74 0.21 Stable 9 TO 10 4:1 0.50% 10.26 Bare Ground 0.020 0.85 3.55 0.27 Needs Ve Vegetation 0.035 1.05 2.33 0.33 Stable 14 TO 15 4:1 0.50% 1.08 Bare Ground 0.020 0.37 2.02 0.11 Needs Ve Vegetation 0.035 0.45 1.33 0.14 Stable 13 TO 15 4:1 0.50% 0.76 Bare Ground 0.020 0.32 1.85 0.10 Needs Ve Vegetation 0.035 0.39 1.22 0.12 Stable 15 TO 16 4:1 0.50% 4.55 Bare Ground 0.020 0.63 2.90 020 Needs Ve Vegetation 0.035 0.77 1.91 0.24 Stable 16 TO 10 4:1 0.50% 43.78 Bare Ground 0.020 1.46 5.11 0.46 Needs Liner Vegetation 0.035 1.81 3.36 0.56 Stable 11 TO 18 4:1 0.50% 1.12 Bare Ground 0.020 0.37 2.04 0.12 Needs Ve Vegetation 0.035 0.46 1.34 0.14 Stable 10 TO 17 4:1 0.50% 1.47 Bare Ground 0.020 0.41 2.19 0.13 Needs Ve Vegetation 0.035 0.51 1.44 0.16 Stable • • • • 17 TO 22 4:1 0.50% 0.57 Bare Ground 0.020 0.29 1.72 0.09 Needs Ve Vegetation 0.035 0.35 1.13 0.11 Stable 20 TO 19 4:1 0.50% 0.56 Bare Ground 0.050 0.29 1.72 0.09 Needs Veg Vegetation 0.065 0.35 1.13 0.11 Stable 21 TO 22 4:1 0.50% 2.96 Bare Ground 0.080 0.53 2.60 0.17 Needs Ve Ve etation 0.095 0.66 1.71 0.21 Stable 21 TO 19 4:1 0.50% 1.37 Bare Ground 0.110 0.40 2.15 0.12 Needs Ve Ve etation 0.125 0.49 1.41 0.15 Stable 22 TO 26 4:1 0.50% 7.17 Bare Ground 0.140 0.74 3.25 0.23 Needs Ve Ve etation 0.155 0.92 2.13 0.29 Stable 11 TO 12 4:1 0.50% 64.89 Bare Ground 0.170 1.70 5.63 0.53 Needs Liner Ve etation 0.185 2.09 3.70 0.65 Stable 18 TO 24 4:1 0.50% 6.82 Bare Ground 0.170 0.73 3.21 0.23 Needs Ve Ve etation 0.185 0.90 2.11 0.28 Stable 20 TO 23 4:1 0.50% 8.35 Bare Ground 0.200 0.79 3.37 0.25 Needs Ve Ve etation 0.215 0.97 2.22 0.30 Stable 23 TO 24 4:1 0.50% 28.25 Bare Ground 0.230 1.24 4.58 0.39 Needs Liner Ve etation 0.245 1.53 3.01 0.48 Stable 24 TO 25 4:1 0.50% 39.28 Bare Ground 0.260 1.41 4.97 0.44 Needs Liner Ve etation 0.275 1.73 3.27 0.54 Stable Unless otherwise noted, "Needs Liner" =Excelsior Matting over seed, straw and tack Contact : Brandon Powell PO Box 1108 Nashville, NC 27856 Phone #: 252.459.8196 • a 0 a w~ ,- U T (n L ~~ ~~ ._ o c°' zw w J H D W ~, • UTt~T NzorF~TloN -~~ ~ 'ta ~-E S Z USE FIGrUIeE 8.O(D ~QSt~. QLS = o . s8 ~F s E La (o ~ .~ i duo ' o • 3 ~GP ~_ ~C. ~~~ ~--._____. tom' --~ fi" ~C l~ SG Gl~}SS q R.I ~RA-P oV~~ rVt l -~4F1 140 N q I tiS p~P~7-~-} , ~f-S S 'Tb FES USE FiCU)~ 8. D(o Rcp ySI ~--- (Q ~ -----~ ~, ~P --~ ~ ~r119n.~ ~ I ~~ ~ ~ (a ~ I T Kn~ov~N QZs : I ~ . g ~ cF s M1N. RF.Q w ' a~ _ 0 3 ' ->~" UsE C, c.~tss A w P~ csva~- rn 12q.~~ , ~ rs 9'' !N ~~~p-~~{ , • m a a .~ a E w~ r. U T (n L ~~ ~~ ~, .~ o °' zW c~ w J ~" W ~~ • U _~~~g Ta F~S~' USE FIG-U12E $,p(o ~, .~ R w ~ r. k~J0 QL5 UJn1 $ • ~'T VLF = ~{. S`{ MIN. E La ~ w = ~ , ~ dsn = o . 30 ON ~C l~ St GC.~SS Q Rl ~Pf2A-p ovt~ r'Y! 11~4F1 140 N 9 I N p~-p-~-~ , DES (o Ta FES l USE F1GrU12~ 8, D(o O _ , fZGp $' ~C.. (E-- ~l o ---~ q ~. ~c~---- ro' --~I 1` KNOWN QZs ~ ~o . ~f I ~ZS = 7.3Z MIN. RF~Q. c..~.= to w ~ ~•s~ a~, = o . 3v • I '~ UsE Cc.~tss w P,~(3P bv~ rn ~ 2q~~ , ~ r~S R ~, i~ a~.p-r~{ f • a ro d 0 a w ° r U T (n ~~ ~~ ~~ ~, .~ .~ zW w J 0 W ~j • V _ ~E S ~ 9 -ta F~-s 2i USE FIGrUI?E 8.ot~ QLS-2.~~ ~ ut~ ~ ~ Z~ MIN. E . La ~ to ' so o . 3 r. RGP 4 -~ ~ -~ ON ~C U S~ Gv455 A RI ~RA-Q oVt~ rVt I Ie14Fi I CFO N -1 I ~ p~P')"H . • Sediment Basin Worksheet (Drainage Area Must be Less Than 100 Acres) Area Disturbed = 3 , ~-( `] Acres Runoff Area = Z I . CQ S Acres Q,o=c x i x A =,35 x~x 21.c~S _ ~ cfs Basin Volume Calculation: Volume of Sediment = ( ,3• `{ Ac.) x (1800 cf sed./year) x (1 year) = 2'-( cf Assume ~_ foot of basin depth, therefore area of the pit 2~ 2 Square Feet Try (~y Z wide) x (Z (o long) x (~_ foot deep) Sediment Basin Surface Area Calculation: Surface Area (SF) = Quo x 435 sflcfs = S 7 x 435 sf/cfs = ZS, oS~Lsf T = ZSf oSZ ~' 0 2 Surface Area - too T o~c. Use (~? wide) x (2 long) x ( ,..3 foot deep) Sediment Basin = 2S_; o_ > Z~ oS2 Surface Area - ol[. Weir Design and Velocity Check: Quo = 7. S cfs; Q = CLHs/z; H = [Q/CL]z/s _ [ s ~ -/ (2.68)( (j )]2/3 = Z.IS feet Velocity Check ~ (~_~j)/( ~ S ) ( Z.1 S ) = fps, OK / J1~/ Z 6Jv~ti8 Lrr 'fA¢.w~.s Sediment Basin Worksheet (Drainage Area Must be Less Than 100 Acres) Area Disturbed = ~ ~ 77 Acres Runoff Area = ~ 3 , ~~ Acres Quo=C x I x A =,35 x7lo x 13.5`{ = 37. o$ cfs Basin Volume Calculation: Volume of Sediment = ( (. `7 `~ Ac.) x (1800 cf sed./year) x (1 year) = I cf • Assume ~_ foot of basin depth, therefore area of the pit ~r y4 Z Square Feet Try ( wide) x ( long) x foot deep) Sediment Basin Surface Area Calculation: Surface Area (SF) = Quo x 435 sf/cfs = 7 , 08 x 435 sf/cfs _ (a l~ sf Surface Area - Use (~~ wide) x (~~ long) x ( ,3 foot deep) Sediment Basin Zoc~ ~ ~ Surface Area - D(L • Weir Design and Velocity Check: Quo = •37.0 cfs; Q = CLH3/2; H = [Q/CL]2/s _ [ 37.08 /(2.68)( I Z )~2/s _ .lo feet Velocity Check ~ (37.08 )/( l 2 ) ( (. S ) = Z, ,p(Q fps, OK ~/ ~~ uSC Buoyancy Resistance Calculations for Steel Riser Basin 1 Assumptions: Unit Weight of Saturated Soil [gSe,] = 120 pcf Unit Weight of Steel [g~nc] = 490 pcf Unit Weight of Water [gr„] = 62.4 pcf Base Length [L] = 4 feet Base Width [W] = 4 feet • • Known: Inside Diameter of Wetwell (ft) _ Outside Diameter of Wetwell (ft) _ Depth of Structure (ft) _ Minimum Base Slab Thickness (in) _ Minimum Top Slab Thickness (in) _ Average Invert Thickness (in) _ Base Slab Area (ftz) _ Displacement Volume, Wetwell (ftz) _ Displacement Volume, Base Slab (ftZ) _ Buoyant Force = Effective Weight of Soil Over Slab Extension = Structure Weight, Walls = Structure Weight, Invert = Structure Weight, Top Slab = Structure Weight, Base Slab = Structure Weight, Total = ID OD D T Tts Ti A Vw Vbs B S Ww Wi Wts Wbs W 3 3.1 3 4 0 4 (L x W) or pi(OD/2)ZD A(T/12) (VW + Wn$) x 9w (9set - 9W) x (A-pi(OD/2)Z)D (p1(OD/2)2 - pl(ID/2)2)Dgconc pl(I D/2)ZT~gccnc pi(OD/2)2(Tt$/12)gccnc A(T/12)gccnc Ww + Wi + Wts +Wbs Table of Calculations: A Ww Wi Wts Wbs W (ft) (Ibs) Ibs) (Ibs (Ibs) (Ibs) . 12.56 703.91 1153.95 0:00 201:487 99p ~ Vw Vbs B S (ft) (ft) (Ibs (Ibs 22.63 4:19 1873:46 8$` W + S = 477;12 B = 1673.46 FOS Is W + S > B? Y S 2,85 Conclusion: Since the weight of the structure and the base slab is greater than the buoyancy for of the wetwell, the resistance to buoyant force is provided. Buoyancy Resistance Calculations for Steel Riser Basin 2 Assumptions: Unit Weight of Saturated Soil [gSet] = 120 pcf Unit Weight of Steel [g~nc] = 490 pcf Unit Weight of Water [gW] = 62.4 pcf Base Length [L] = 4 feet Base Width [W] = 4 feet • • Known: Inside Diameter of Wetwell (ft) = ID Outside Diameter of Wetwell (ft) = OD Depth of Structure (ft) = D Minimum Base Slab Thickness (in) = T Minimum Top Slab Thickness (in) = Tts Average Invert Thickness (in) = Ti Base Slab Area (ftz) = A Displacement Volume, Wetwell (ftz) = Vw Displacement Volume, Base Slab (ftz) = Vbs Buoyant Force = B Effective Weight of Soil Over Slab Extension = S Structure Weight, Walls = Ww Structure Weight, Invert = Wi Structure Weight, Top Slab = Wts Structure Weight, Base Slab = Wbs Structure Weight, Total = W Table of Calculations: (LxW)or 3 3.1 3 4 4 pi(OD/2)2D A(T/12) (VW + Wbg) x 9W (9~t - 9w) x (A-pi(OD/2)2)D (pi(OD/2)2 - pi(ID/2)Z)Dgccnc pi(ID/2)ZTi9conc pl(OD/2)2(Tts/12)gconc A(T/12)gccnc Ww + Wi + Wts +Wbs A Ww Wi Wts Wbs W (ft) (Ibs) (Ibs) (Ibs) (Ibs) (Ibs) 12:58 703:91 1153,95 0.00 2081.' 87 3909:3262 Vw Vbs B S (ft) (ft3) (Ibs) (Ibs 22.63 4.19 1 73.46. ' B :8.79' W+S= 477..12 B = 1 ~7~:4~ FOS Is W + S > B~ YES 2.85. Conclusion: Since the weight of the structure and the base slab is greater than the buoyancy for of the wetwell, the resistance to buoyant force is provided.