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Home My WebLink About20220331_2_ESCr.., Attachment 2 Stormwater and Erosion Control Calculations RECEIVED MAR 3 12022 LAND QUALITY MINING PROGRAM Steel Gray Mine Sediment Trap Trap / Skimmer Size Drainage Area Surface Storage Spillway Area Volume length T-1 16'X60'X4 0.6 acres 960ft2 3840ft3 4.0' T-IA 10'X33'X4' 0.12 acres 330ftz 1320ft3 4.0' T-2 20'x110'x4' 1.87 acres 2200ft2 8800ft3 6.0' T-3 26'x100'x3' 2.12 acres 2600ftz 10400ft3 6.0' T-4 36'x125'x4' 3.5 acres 4500ft2 18000ft3 10.0' T-5 36'x99'x4' 1.95 acres 3564ft2 14256ft3 9.54 Runoff Calculations for Trap T-1 rlascrintinn Acres C-Value Coef. Bare Sandy Soil level 0 0.5 0 Bare Soil (sloping) 0.6 0.5 0.3 Grassland & disturbed Areas 0 0.5 0 Woodlands 0 0.3 0 Roadway ravel 0 0.65 0 Totals 0.6 0.3 C = 0.3 (coef) / 0.6 (acres) = 0.5 i = Rainfall Intensity for 10 year, 1 day storm = 7.06 inches Q = (C)(i)(A) = 0.5 X 7.06 X 0.6 = 2.118 cfs i = Rainfall Intensity for 2 year, 1 day storm = 5.21 inches Q = (C)(i)(A) = 0.5 X 5.21 X 0.6 = 1.563 cfs i = Rainfall Intensity for 25 year, 1 day storm = 8.09 inches Q = (C)(i)(A) = 0.5 X 8.09 X 0.6 = 2.427 cfs llww� lqwv Sediment Trap Trap T 1 Trapping Effeclency Drainage Area Acres 0.6 A = 0.01 X (0) 1 2.118 = 0.0212 X 43560 922.E M Required Basin Size 16'X60 M(minimu n) Ft2 Surface area 960 Ft3 Storage area 3840 Trap to be deaned at the plont where the basin no longer funclions well or Is at 50% capadty. \„� Runoff Calculations for Trap T-1A Description Acres C-Value Coef. Bare Sandy Soil level 0 0.5 0 Bare Soil (sloping) 0.21 0.5 0.105 Grassland & disturbed Areas 0 0.5 0 Woodlands 0 0.3 0 Roadway ravel 0 0.65 0 t otals U.21 U.1 Ub C = 0.105 (coef) / 0.21 (acres) = 0.5 i = Rainfall Intensity for 10 year, 1 day storm = 7.06 inches Q = (C)(i)(A) = 0.5 X 7.06 X 0.21 = 0.7413 cfs i = Rainfall Intensity for 2 year, 1 day storm = 5.21 inches Q = (C)(i)(A) = 0.5 X 5.21 X 0.21 = 0.54705 cfs i = Rainfall Intensity for 25 year, 1 day storm = 8.09 inches Q = (C)(i)(A) = 0.5 X 8.09 X 0.21 = 0.84945 cfs M m Sediment Trap Trap T 1A Trapping Effeciency Drainage Area Acres 0.21 A = 0.01 X (0) 0.74 = 0.0074 X 43560 =1 322.3 fl2 Required Basin Size 10'X3TXC(mtnimum) Ft2 Surface area 330 Ft3 Storage area 1320 Trap to be deaned at the piont where the basin no longer functions well or Is at 50% c apadty. \4WOO/ Runoff Calculations for Trap T-2 flacrrintinn Acres C-Value Coef. Bare Sandy Soil level 0 0.5 0 Bare Soil (sloping) 0.75 0.5 0.375 Grassland & disturbed Areas 0 0.5 0 Woodlands 1.12 0.3 0.336 Roadway ravel 0 0.65 0 Totals 1.87 0.711 C = 0.711 (coef) / 1.87 (acres) = 0.3802139 i = Rainfall Intensity for 10 year, 1 day storm = 7.06 inches Q = (C)(i)(A) = 0.38021 X 7.06 X 1.87 = 5.01966 cfs i = Rainfall Intensity for 2 yea( 1 day storm = 5.21 inches Q = (C)(i)(A) = 0.38021 X 5.21 X 1.87 = 3.70431 cfs i = Rainfall Intensity for 25 year, 1 day storm = 8.09 inches Q = (C)(i)(A) = 0.38021 X 8.09 X 1.87 = 5,75199 cfs \00 �.d Sediment Trap EM-3 Trap T 2 Trapping Effeciency Drainage Area Acres 1.87 A = 0.01 X (0) 5.02 = 0.0502 X 43660 Basin Size 2VX1 I UM(minimum) Fit Surface area 2200 Ft3 Storage area 8800 2186.7 ft2 Required Trap to be cleaned at the plont where the basin no longer functions well or is at 50% capacity. Runoff Calculations for Culvert C-1 nimgn.rinfinn Acres C-Value Coef. Bare Sandy Soil level 0 0.5 0 Bare Soil (sloping) 0.85 0.7 0.595 Grassland & disturbed Areas 0 0.5 0 Woodlands 1.12 0.3 0.336 Roadway ravel 0 0.65 0 Totals 1.97 0.931 C = 0.931 (coef) 1 1.97 (acres) = 0.4725888 i = Rainfall Intensity for 10 year, 1 day storm = 7.06 inches Q = (C)(i)(A) = 0.47259 X 7.06 X 1.97 = 6.57286 cfs i = Rainfall Intensity for 2 year, 1 day storm = 5.21 inches Q = (C)(i)(A) = 0.47259 X 5.21 X 1.97 = 4.85051 cfs i = Rainfall Intensity for 25 year, 1 day storm = 8.09 inches Q = (C)(i)(A) = 0.47259 X 8.09 X 1.97 = 7.53179 cfs \11111110, Project Description Worksheet Circular Channel - C-1 Flow Element Circular Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.010 Slope 0.010000 Rift Diameter 15 In Discharge 7.53 cis Results Depth 0.92 ft Flow Area 1.0 fr Wetted Perimeter 2.59 ft Top Width 1.10 ft Critical Depth 1.09 ft Percent Full 73.9 % Critical Slope 0.007304 Rift Velocity 7.74 ftfs Velocity Head 0.93 ft Specific Energy 1.86 ft Froude Number 1.45 Maximum Discharge 9.03 cis Discharge Full 8.40 cis Slope Full 0.008041 Rift Flow Type Supercritical � tb to 0.92 It I lI V:t� H:1 NTS `44 Runoff Calculations for Ditch DB-2 nescrintinn Acres C-Value Coef. Bare Sandy Soil level 0 0.5 0 Bare Soil (sloping) 0.6 0.7 0.42 Grassland & disturbed Areas 0 0.5 0 Woodlands 0 0.3 0 Roadway ravel 0 0.65 0 Totals 0.6 0.42 C = 0.42 (coef) / 0.6 (acres) = 0.7 i = Rainfall Intensity for 10 year, 1 day storm = 7.06 inches Q = (C)(i)(A) = 0.7 X 7.06 X 0.6 = 2.9652 cfs i = Rainfall Intensity for 2 year, 1 day storm = 5.21 inches Q = (C)(i)(A) = 0.7 X 5.21 X 0.6 = 2.1882 cfs i = Rainfall Intensity for 25 year, 1 day storm = 8.09 inches Q = (C)(i)(A) = 0.7 X 8.09 X 0.6 = 3.3978 cfs M Project Description Worksheet Trapezoidal Channel - DB-2 Flow Element Trapezoidal Channel Method Manninjs Formula Solve For Channel Depth Input Data Mannings 0.104 Coefficient Slope 0.020000 ftlft Left Side Slope 2.00 V : H Right Side Slope 2.00 V : H Bottom Width 2.00 ft Discharge 3.39 cfs Results Depth 0.97 ft Flow Area 2.4 fN Wetted Perimeter 4.17 ft Top Width 2.97 ft Critical Depth 0.43 ft Critical Slope 0.280312 ft/ft Velocity 1.40 ft/s Velocity Head 0.03 ft Specific Energy 1.00 ft Froude Number 0.27 Flow Type Subcdflcal Determine sheer stress: T= 62.4X 0.97 X 0.02 s 1.21 IbV Permissible Sheer Stress 4.0 IMF Rip Rap Lining OK 0.87 k -2.00 V:1 H2.0 NTS `4. Runoff Calculations for Ditch DB-2A r)escrintinn Acres C-Value Coef. Bare Sandy Soil level 0 0.5 0 Bare Soil (sloping) 0.24 0.7 0.168 Grassland & disturbed Areas 0 0.5 0 Woodlands 0 0.3 0 Roadway ravel 0 0.65 0 Totals 0.24 0.168 C = 0.168 (coef) / 0.24 (acres) = 0.7 i = Rainfall Intensity for 10 year, 1 day storm = 7.06 inches Q = (C)(i)(A) = 0.7 X 7.06 X 0.24 = 1.18608 cfs i = Rainfall Intensity for 2 year, 1 day storm = 5.21 inches Q = (C)(i)(A) = 0.7 X 5.21 X 0.24 = 0.87528 cfs i = Rainfall Intensity for 25 year, 1 day storm = 8.09 inches Q = (C)(i)(A) = 0.7 X 8.09 X 0.24 = 1.35912 cfs \whov \VAFi Project Description Worksheet Trapezoidal Channel - DB-2A Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth Input Data Mannings Coefficient 0.104 Slope 0.020000 ft1ft Left Side Slope 2.00 V : H Right Side Slope 2.00 V : H Bottom Width 2.00 ft Discharge 1.36 cfs Results Depth 0.66 ft Flow Area 1.3 ftz Wetted Perimeter 3.24 ft Top Width 2.55 ft Critical Depth 0.24 ft Critical Slope 0.305306 ft/ft Velocity 1.08 ft/8 Velocity Head 0.02 ft Specific Energy 0.57 ft Froude Number 0.27 Flow Type Subcritical Determine sheer stress: T= 62.0 0.66 X 0.02 0 0.69bW Permissible Sheer Stress 4.0 IMP Rip Rap Uning OK 0.55 ft .._i- VAN H2.0 HTs 5 1 6 1 7 1 a 1 9 1 10 1 11 1 12 1 13 1 14 1 15 1 16 1 1 / I its I IV S1 Ll H1 GI F I Ell IDM In M Cross -Section It min of "-bal 4 'u, 0 - It! ------- T,�p 1 40 me fe� it Flaullt 6 63a Rx, Jai, z a, nil., znd fabr :an sel th", % Plan View — — — — — — 1*35 ore 6.60a P� era a iotprm" ",WrW' Van Racl, A:Amstr 5' r T 2 1 /A V*cs I �md -T pack Abv•riavl A A Mtn 15 thwk Al Filler Fabr - F.pi,i,o 6.69w Rork Dqni =S5 S"Mri Cross Se_licri View 1, =111ilt F.j,n, ,S t2l 9q 1 1V- T- "I I I 'ej 'eanJy omrss he bath ID rsaote BARRIER FENCE DETAIL wire Compacted soil 2 -or min x- RNIM II E. typical Figure 6.20* Temporary earthen dvcimsor chko Coarse aggregate ['version Berm + 18 min 3 1 max 1111 17--= 11 - Figure 6.20b Temporary gravel civerson dike for vehicle crossing modified from Va ISediment1rao �asi t 16 min j:\o%N 0~. ale" Zone • Figum 6.6511; 1,W'W Of PGRX-i Wlk Ic ICT9 V PC slit, W; ff',:w.M wiemalra spoatA woolu(Wqnumscsr iCltyd #40 �CML, MC deW 8 max standard strength faor,., WIth wire fence 6' max extra strength fabric without wire fence ISediment Fence max Steel post T Plastic or wire ties Wire fence Natural ground 8" down 4 4" forward along 24' the trench Filter faanc Vvire fence Cross -Section View Filter Steel fabric Plackfilf trench post and compact Natural thoroughly ground . 4 min T 2 -1' •min Figure 6.62a Installation detail of a sediment fence 17C 16C 15C 14( 13( 12- it( 10( 90 MIRAW fIa 96.0 0+00 0+50 1+00 1+50 sEc'n0N A SCALE- HORIZ. 1"=100' VERL 1"=10' -Ho'an '%W.W 2' 1. -3 5 t st4&' a J` SON,- giii III ';Ooqv�' titer, Ir .1..kamnel 1114" 1� htcx%i.! -ap,t,. sod WS MO)y seas W !ntta " blwsam Messr �Pqrory chomwtl NOW I C." do,. 11 oar 2 swknar rtv, rgoyor, P, 7s o,, 1,'fo,' if tte' s.tam ri 'U top f, "o., so" .'Mr, of 14. b" A.ier,. T1- nr dw to, %OTES oj IL Peg* iC06d .11A 15 ? fl- WC to�r� tis.Tl I.IK I 1�1v mm�j t1w -.11 U ortr'�'t-u IV 1W s• 'Pe 190 17C 16C 15C 14C 13C 12C lic 100 it � a 0 tl Ir WS 106.0 0+00 0+50 1+00 1+50 2T00 2+50 3+00 SECTION B SCALE. HORIZ. 1'=100' VERT. 1*=10' ;aped Riprap Channel + Desi. *,ck ss Lit-. ttck subvfadL exc wq -er layer c-avel or laciric Trapezo al Riprap Channel iln top width Igib, A FigW063ts layer, ;;,a,ei Paiabolic-s-iapecl Riprap Cl-annel C�.�ijn lop width dupill r ilckress subGrade excaw I-mer avir. grivel o, 0 hI��illlllS 0 0 C/) CD :2 z= M 9 — (D Cf) C-) R U) fy- Lij :Z 0- W cn 0 cri L� -Z 0 n Lij Lj a- =D CC) P 1 1 6 1 7 8 9 10 1 11 12 13 1 14 1 15 1 16 17 1 18 1 1 kk 0 SEAL 23960 M L C) W 0 LL z 0 co 03 U) z zm < U _j _j W.A Ai CO E-4 r__ z 0 00 z LLJ CILi L C'q LLJ it o) c) ON z 6 P C'4 z _zU)N 0 U) Lj UJ I LLJ co ;_7 V) U) F- Z 0 — (14 LJ z Ckf =) CL 00 8 UJI U U) UJ LLI 0 _j :D 0 H LL_ ,:c U)Q_ < _j z _j 0 C) F 0 z z W z W U) E LL < W < D (D of 0 (3 U_ W _j (D D W M W U) LU Z:) —1 ca C U) z D 0 < F- W W C) T c_ C) 3: B Sheet No.: 0 MP-3 A U 0 ,_ 0 1 a- CD 1 20