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Home My WebLink AboutSW6191102_MCPHAIL MEADOWS STORM AND EC CALCS_12/6/2019McPhail Meadows Storm Water and Erosion & Sedimentation Control Calculations Owner: Southeastern Construction of Rockfish 771 Bostic Road Raeford, NC 28376 McPhail Meadows 2 The certification shown below applies only to the items listed on this 'Table of Contents' Drainage Area Map Runoff Coefficient Kirpich Equation NOAA Rainfall Intensity HDS-5 Culvert Capacity Rip Rap Outlet Apron Manning's n Table of Contents 1 Page (Print to 11"x17"; print all others below to 8.5" x 111.) 1 Page 1 Page 1 Page 1 Page 2 Pages 3 Pages Conveyance and Temporary Diversion Swales 9 Pages Temporary Sediment Traps 4 Pages HILLIARD - - --- ENGINEERING Author: Jarrod E. Hilliard, PE, CFM PO Box 249 Sanford, NC 27331 (919) 352-2834 NC License No. P-0836 •CAR�C'� " E 35 ro_ Date: 10/27/19 D RAI NAG E AREA MAP �- -- - ------- _-- L --' 23o 00 O � N. two N RUNOFF COEFFICIENT 0 Table 8.03b Value of Runoff Coefficient (C) for Rational Formula Land Use C Land Use C Business: Lawns: Downtown areas 0.70-0.95 Sandy soil, flat, 2% 0.05-0.10 Neighborhood areas 0.50-0.70 Sandy soil, ave., 0.10-0.15 2-7% Residential: Sandy soil, steep, 0.15-0.20 Single-family areas 0.30-0.50 7% Multi units, detached 0.40-0.60 Heavy soil, flat, 2% 0.13-0.17 Multi units, Attached 0.60-0.75 Heavy soil, ave., 0.18-0.22 Suburban 0.25-0.40 2-7% Industrial: Heavy soil, steep, 0.25-0.35 Light areas 0.50-0.80 7% Heavy areas 0.60-0.90 Agricultural land: Parks, cemeteries 0.10-0.25 Bare packed soil Smooth 0.30-0.60 Playgrounds 0.20-0.35 Rough 0.20-0.50 Cultivated rows Railroad yard areas 0.20-0.40 Heavy soil no crop 0.30-0.60 Heavy soil with Unimproved areas 0.10-0.30 crop 0.20-0.50 Streets: Sandy soil no crop 0.20-0.40 Asphalt 0.70-0.95 Sandy soil with Concrete 0.80-0.95 crop 0.10-0.25 Brick 0.70-0.85 Pasture Heavy soil 0.15-0.45 Drives and walks 0.75-0.85 Sandy soil 0.05-0.25 Woodlands 0.05-0.25 Roofs 0.75-0.85 NOTE: The designer must use judgement to select the appropriate C value within the range for the appropriate land use. Generally, larger areas with permeable soils, flat slopes, and dense vegetation should have lowest C values. Smaller areas with slowly permeable soils, steep slopes, and sparse vegetation should be assigned highest C values. Source: American Society of Civil Engineers 8.03.6 Rev. 6/06 KIRPICH EQUATION FOR TIME OF CONCENTRATION McPhail Meadows KIRPICH EQUATION FOR TIME OF CONCENTRATION COMPUTATIONS T. = [ K/1281 [L3/H]0.385 K: 1 L: 481.63 H: 7 T,: 4.63 Minutes Use: 5.00 minutes for all NOAA RAINFALL INTENSITY Precipitation Frequency Data Server https ://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=34.9982&... NOAA Atlas 14, Volume 2, Version 3 ' Location name: Raeford, North Carolina, USA*''��" Latitude: 34.9982°, Longitude:-79.1082' e Elevation: 237.08 ft** I, * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF-graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)l Average recurrence interval (years) Duration 1 2 5 25 50 100 200 500 1000 000��0000� 5.22 6.17 7.19 8.89 6 9.510.2 10.8 11.6 12.1 5-min � (4.74 5.78) (5.60 6.83) (6.53 7.97) (7.21 8.80)1 (8.02-9.80) (8.60-10.5) (9.13 11.2) (9.62-11.9) 4.17 4.93 5.76 F 7.09 F 7.61 F 8.56 9.14 9.55 10-min (3.79 4.62) (4.48-5.46) (5.23-6.38) 1 (6.38-7.81) (6.85-8.38) (7.25 8.91) (7.63-9.41) (8.06-10.0) 3.48 F 4.13 4.86 5.37 5.99 6.43 6.83 7.20 7.67 7.99 15-min F(4.86-5.93) (3.16-3.85) (3.75-4.58) (4.41-5.38) (5.40-6.60) (5.78-7.07) 1 (6.11-7.51) 1 (6.41-7.92) 2.38 2.85 3.45 3.89 4.44 4.84 5.23 5.61 6.106.47 30-min (2.16-2.64) (2.59-3.16) (3.13-3.82) (3.52-4.30) (4.00-4.89) (4.35-5.33) (4.68 5.75) (4.99-6.16) (5.38-6.7-]E(5 67 7.11) 1.49 1.79 2.21 2.53 2.95 3.28 3.60 3.93 4.72 60-min =(34.81) (1.35-1.65) (1.63-1.98) (2.01 2.45) (2.29 2.80) (2.66 3.26) (2.95 3.61) (3.22 3.96) (3.50 4.32) (4.14 5.19) 0.865 F 1.05 1.32 1.53 1.81 2.03 2.25 2.49 2.80 3. 55 2-hr (0.778-0.975) (0.944-1.18) (1.18-1.48) 1 (1.61-2.03) 1 (1.80-2.28) 1 (2.18-2.79) 1 (2.43-3.13) (2.63-3.41) 0.611 0.739 0.934 1.09 1.31 1.48 1.66 1.86 2.13 2.35 3-hr (0.549 0.690) (0.665 0.835) (0.838 1.05) (0.976 1.23) (1.16 1.47) (1.31 1.66) (1.46 1.87) (1.62 2.08) (1.83 2.38) (2.00 2.63) 0.365 0.443 0.559 0.654 0.786 0.894 1.01 1.13 1.30 1.44 6-hr (0.330-0.408) (0.400-0.494) (0.505-0.623) (0.588-0.728) (0.701-0.872) (0.793-0.991) (0.887 1.12) (0.984 1.25) (1.12-1.44) 0.214 0.259 0.329 0.387 0.468 0.536 0.608 0.686 0.797 F 0.889 12-hr (0.193-0.239) (0.234-0.290) (0.297-0.368) (0.347-0.431) (0.417-0.520) (0.473-0.594) (0.532-0.672) (0.593-0.757) (0.680-0.880) (0.748-0.980) 0.127 0.153 0.195 0.227 0.273 0.309 0.347 0.386 0.4 1 IF 0.484 24-hr (0.118-0.137) (0.142-0.166) (0.180-0.210) (0.210-0.245) (0.251-0.294) (0.284-0.333) (0.318-0.374) (0.352-0.416) (0.400-0.475) (0.437-0.522) 0.073 0.089 F 0.112 0.130 0.155 0.175 0.196 0.218 0.248 0.271 2-day (0.068 0.079) (0.083-0.095) (0.104-0.120) (0.120-0.139) (0.143-0.167) (0.161-0.188) (0.180-0.211) (0.199-0.234) (0.225-0.267) (0.246-0.292) F--0-.0-5-2-11 0.063 F 0.078 0.091 0.108 0.122 0.136 0.151 0.172 0. 888 3-day (0.049 0.056) (0.059-0.067) (0.073-0.084) (0.085-0.097) (0.100-0.116) (0.113-0.131) (0.126-0.146) (0.139-0.162) (0.157-0.184) (0.171-0.202) 0.041 0.050 F 0.062 0.072 0.085 0.096 0.107 0.118 0.134 F 0.146 4-day (0.039 0.044) (0.047-0.053) (0.058-0.066) (0.067-0.076) (0.079-0.091) (0.089-0.102) (0.098-0.114) (0.109-0.126) (0.122-0.143) (0.133-0.156) 0.027 0.033 0.040 I 0.046 0.055 0.061 0.068 0.075 0.084 F 0.092 7-day (0.026 0.029) (0.031-0.035) (0.038-0.043) (0.043-0.050) (0.051-0.058) (0.057-0.065) (0.063-0.073) (0.069-0.080) (0.077-0.090) (0.084-0.099) 0.022 0.026 F 0.032 0.036 0.042 0.047 0.051 0.056 0.062 F 0.0 77 10-day (0.021-0.023) (0.025-0.028) (0.030-0.034) (0.034-0.038) (0.039-0.045) (0.043-0.049) (0.048-0.054) (0.052-0.059) (0.058-0.066) (0.062-0.072) 0.015 0.018 1 0.021 0.024 0. 227 0.030 0.033 0.036 0.039 IF 0. 442 20-day (0.014 0.016) (0.017-0.019) (0.020-0.022) (0.022-0.025) (0.025-0.029) (0.028-0.032) (0.031-0.035) (0.033-0.038) (0.036-0.042) (0.039-0.045) 0.012 0.015 F 0.017 0.019 0.021 0.023 0.025 0.027 0.030 0.032 30-day (0.012-0.013) (0.014-0.015) (0.016-0.018) (0.018-0.020) (0.020-0.023) (0.022-0.025) (0.024-0.027) (0.025-0.029) (0.028-0.032) (0.029-0.034) 0.010 0.012 0.014 0.015 0.017 0.019 0.020 0.021 0.023 0.024 45-day (0.010-0.011) (0.012-0.013) (0.013-0.015) (0.015-0.016) (0.016-0.018) (0.018-0.020) (0.019-0.021) (0.020-0.023) (0.022-0.024) (0.023-0.026) 0.009 F 0. 111 F 0.012 0.014 0. 115 F 0. 116 F 0. 117 0.018 0.020 0. 221 60-day �(0.009-0.010) (0.010-0.011) (0.012-0.013) (0.013-0.014) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019) (0.019-0.021) (0.020-0.022) Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical 1 of 4 9/28/2019, 2:55 PM H DS-5 CULVERT CAPACITY PROJECT: HC1901 STATION: 5+60 CULVERT EVALUATION FORM McPhail Meadows Sheet: 1 Of 1 DESIGNER/DATE: JEH 10/25/2019 Evaluate Proposed Culvert REVIEWER/DATE: JEH 10/25/2019 HYDROLOGICAL DATA 1ROADWA7 ELEVATION 234.63 Ift. W X METHOD: Rational 233.63 jElha (ft) X DRAINAGE AREA: 2.49 ac WATER WA H 0 � CHANNEL SHAPE: a - - - - - - - - - - Elsf 232.00 — — — — — — WATER SURFACE w ROUTING: ••.. ......... ORIGINAL STREAM —T�/�/ ................. • DESIGN FLOWS/TAILWATER R.I. (YEARS) FLOW (cfs) TW (ft) s = So - T / Lo 25 1 8.85 1 0.25 231.83 jEli (ft) IS= 1 1.00% 231.3 jElo (ft) Lo 1 53 CULVERT DESCRIPTION FLOW PER MATERIAL - SHAPE - SIZE (in) - ENTRANCE TOTAL FLOW BARREL Q / N r NUMBER OF BARRELS TO TRY: 1 SHAPE: C=CIRCULAR, A=ARCH, B=BOX Q (cfs) (1) RC ICI 18 O 8.85 8.85 HEADWATER CALCULATIONSINLET o m 2 c 3 m <j = w w E E CONTROL OUTLET CONTROL HWI / D T Elhi TW do + D ho H EI ho (2) Hwi (3) (4) (5) do 2 (6) ke (7) (8) 1.2 1.80 0.17 233.63 0.25 1.22 1.36 1.36 0.9 233.56 233.63 O.K. (Chart 1 B) (Chart 4B) (Chart 5B) F-- (1) USE Q / NB FOR BOX CULVERTS(PIQ"M27^2)-(M27^2*ACOS(M28/M27)-M28"SQRT(M27^2-M28^2) (2) FROM HDS-5 DESIGN CHARTS (3) T = Hwi - (ELhd-Elsf), T IS ZERO FOR CULVERTS ON GRADE (4) Elhi = Hwi+Eli (5) TW BASED ON DOWNSTREAM CONTROL OR FLOW DEPTH IN CHANNEL (6) ho = TW or (dc + D/2), (WHICHEVER IS GREATER) (7) FROM HDS-5 DESIGN CHARTS (8) Elho = Elo + H + ho r (ft.):l 0.75 d (ft):1 1.05 Over Half Area of Pipe (tt-): 1.77 0.885 ow rea 9.77 Outlet Velocity (ft/s): 5.00 of Pipe Elevation @ Inlet (ft): 233.58 Cover @ CL Road (ft): 9.32 1 Use Min. Cl. IV )TF• FRFFR(10RI1 = 1' RIP RAP OUTLET APRON User Input Data Calculated Value Reference Data Designed By: JEH 10/25/2019 Checked By: JEH 10/25/2019 Company: Hilliard Engineering, PLLC Project Name: McPhail Meadows Project No.: HC1901 Site Location (City/Town) Raeford, NC Culvert Id. Sta 5+60 Total Drainage Area (acres) 2.49 Step 1. Determine the tailwater depth from channel characteristics below the pipe outlet for the design capacity of the pipe_ If the tailwater depth is less than half the outlet pipe diameter_ it is classified minimum tailwater condition. If it is greater than half the pipe diameter_ it is classified maximum condition. Pipes that outlet onto wide flat areas N%rith no defined channel are assumed to have a mnnnnim tailwater condition unless reliable flood stage elevations show otherwise. Outlet pipe diameter, Do (in.) Tailwater depth (in.) Minimum/Maximum tailwater? Discharge (cfs) Velocity (ft./s) 18 0.25 Min TW (Fig. 8.06a) 7.94 4.5 Step 2. Based on the tailwater conditions determined in step 1. enter Figure 8.06 a or Figure 8.06b. and determine d50 riprap size and minimum apron length (L,). The d5o size is the median stone size in a well -graded riprap apron_ Step 3. Determine apron width at the pipe outlet, the apron shape, and the apron width at the outlet end from the same figgue used in Step 2. Riprap d50, (ft.) Minimum apron length, La (ft.) Apron width at pipe outlet (ft.) Apron shape Minimum TW Figure 8.06a 0.25 9 4.5 Trapezoidal Maximum TW Figure 8.06b Apron width at outlet end (ft.) 10.5 1.5 Step 4. Derernune the maximum stone diameter: d„ ,al = 1.5 x d50 Minimum TW Max Stone Diameter, dmax (ft.) 0.375 Step 5. Deternune the apron thickness: Apron Thickness(ft.) Apron thickness = '1.5 x dF,,, Minimum TW 0.5625 Maximum TW 0 Maximum TW 0 Step 6. Fit the riprap apron to the site by making it level for the nunimum length. La from Figure 8.06a or Figure 8.06b. Extend the apron farther doiNmstream and along channel banks until stability is assured. Keep the apron as straight as possible and align it with the flow of the receiving stream. Make any necessary alignment bends near the pipe outlet so that the entrance into the receiving stream is straight. - Some locations may require lining of the entire channel cross section to assure stability. It may be necessary to increase the size of riprap where protection of the channel side slopes is necessary (Appendix 8.05). Where overfalls exist at pipe outlets or flows are excessive, a plunge pool should be considered, see page 8.06.8. MANNINGS n FOR CONVEYANCE AND TEMPORARY DIVERSION SWALES This section describes a method for estimating the roughness coefficient n for use in hydraulic computations associated with natural streams_ floodways. and excavated channels. The procedure applies to the estimation of n in Mannuis-s formula (Appendix S.05). Designed By: JEH Date: 09/28/19 Checked By: JEH Date: 09/28/19 Company: Hilliard Engineering, Pllc Project Name: McPhail Meadows Project No.: Site Location (City/Town) Hoke County Site Id. n/a Step 1. Selection of basic value of n. Select a basic n value for a straight, uniform. smooth channel in the natural materials involved. The conditions of straight alignment, uniform cross section, and smooth side and bottom surfaces without vegetation should be kept in mind. Thus. basic n varies only with the material than forms the sides and bottom of the channel. Select the basic n for natural or excavated channels from Table 8.04a. If the bottom and sides of a chiiwiel consist of different materials. select an intermediate value. Channels in earth Basic n value i(n=0.020) 1 0.02 Table 8.04a Step 2. Selection of modifying value for surface irregularity-. This factor is based on the degree of roughness or irregularity of the surfaces of channel sides and bottom. Consider the actual surface irregularity. first in relation to the degree of surface smoothness obtainable with the natural materials involved_ and second in relation to the depths of flow expected. If the surface irregularity is comparable to the best surface possible for the channel materials, assign a modifying value of zero. Irregularity induces turbulence that calls for increased modifying values. Table 8.04b may be used as a guide to selection of these niodifvinQ values. Modifying value: channel surface irregularity Smooth (0.000) 0 Table 8.04b Step 3. Selection of modifying value for variations in the shape and size of cross sections. In considering this factor, judge the approximate magnitude of increase and decrease in successive cross sections as compared to the average. Gradual and uniform changes do not cause significant turbulence. Turbulence increases with the frequency and abruptness of alternation from large to small Annnel .rrtinn,, 1uwaa . -1--- . Shape changes causing the greatest turbulence are those for which flow shifts from side to side in the channel. Select modifying values based on Table 8.04c. Modifying value: channel cross section Gradual (0.000) 0 Table 8.04c Step 4. Selection of modifying value for obstructions. This factor is based on the presence and characteristics of obstructions such as debris deposits. stumps, exposed roots. boulders, and fallen and lodged logs. Take care that conditions considered in other steps not be double -counted in this step. In judging the relative effect of obstructions. consider the degree to which the obstructions reduce the average cross -sectional area at various depths and the characteristics of the obstructions. Sharp -edged or angular objects induce more turbulence than curved, smooth -surfaced objects. Also consider the transverse and longitudinal position and spacing of obstructions in the reach. Select modifying values based on Table 8.04d. Modifying value: effect of obstructions Negligible (0.000) 0 Table 8.04d Step 5. Selection of modifying value for vegetation. The retarding effect of vegetation is due primarily to turbulence induced as the water flows around and between limbs. stems, and foliage and secondarily to reduction in cross section_ As depth and velocity increase, the force of flowing water tends to bend the vegetation. Therefore, the ability of vegetation to cause turbulence is related to its resistance to bending. Note that the amount and characteristics of foliage vary seasonally. In judging the retarding effect of vegetation, consider the following: height of vegetation in relation to depth of flow, its resistance to bending, the degree to which the cross section is occupied or blocked, and the transverse and longitudinal distribution of densities and heights of vegetation in the reach. Use Table 8.04e as a guide. Modifying value: vegetation ILow (0.005-0.010) 1 0.0075 1 Table 8.04e Step 6. Computation of its for the reach. The first estimate of roughness for the reach, ns, is obtained by neglecting meandering and adding the basic n value obtained in step 1 and modifying values from steps _' through 5. r7Y = n + i modifying values Straight channel subtotal, ns 0.0275 Step 7. Meander. The modifying value for meandering is not independent of the other modifying values. It is estimated from the n. obtained In step 67 and the ratio of the meandering length to the straight length. The modifying value for meandering may be selected from Table 8.04f Length of meandering channel (ft) Length of straight line (ft) Meander ratio (ft/ft) Modifying value: meandering of channel Meandering modification 0 100 0 Minor (0.00) 0 Table 8.04f 0.000 'Step S. Computation of it for a channel reach -Mth meandering. Add the modifV11ig value obtained in step 7, to ir,, obtamed m step b. Final roughness coefficient, n 0.028 CONVEYANCE AND TEMPORARY DIVERSION SWALES OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 1 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 F1.27 7.97 Q 1" Event = 0.51 cfs Q 10 year event= 4.05 cfs d= 0.095 ft (min. flow depth for t"storm) A= 0.60 FT^2 d = 0.32 ft (for 10 year storm event) P = 6.60 FT n = 0.030 (computed) R = 0.09 8 = 6 ft (min. width) Q 1" Storm = 0.52 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.88 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 4.13 cfs Avg.S-1 0.007700 ft/ft (avg. slope) W = 6.57 FT V 10 = 1.85 FPS T= Shear Stress Y= 62.4 PCF T= 0.046 PSF d= 0.10 FT S= 0.01 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.52 cfs Bottom of Swale Length 40 If Available Depth (With 6" Freeboard) = 0.5 ft Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge, (CPS) V= Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt= Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R = Product of Velocity and Hydraulic Radius B = Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 150.00 cf Hydraulic Retention = 4.77 minutes CIiANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T < 1 then use Coir Wattle against silt fence : if T > 1 then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge, (CPS) V = Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 2 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.9 1.00 FO.25 7.97 Q 1" Event = 0.23 cfs Q 10 year event= 1.79 cfs d = 0.047 ft (min. flow depth for 1"storm) A = 0.29 FT^2 d = 0.17 ft (for 10 year storm event) P = 6.30 FT n = 0.030 (computed) R = 0.05 8 = 6 ft (min. width) Q 1" Storm = 0.23 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.79 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 1.99 cfs Avg.S=l 0.015500 IftIft (avg. slope) W = 6.28 FT V 10 = 1.80 FPS T= Shear Stress Y= 62.4 PCF T= 0.045 PSF d= 0.05 FT S= 0.02 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.23 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 56.25 cf Hydraulic Retention = 4.10 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 3 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 FO.59 7.97 Q 1" Event = 0.24 cfs Q 10 year event= 1.88 cfs d = 0.048 ft (min. flow depth for 1"storm) A = 0.29 FT^2 d = 0.17 ft (for 10 year storm event) P = 6.30 FT n = 0.030 (computed) R = 0.05 8 = 6 ft (min. width) Q 1" Storm = 0.24 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.80 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 1.99 cfs Avg.S=l 0.015500 IftIft (avg. slope) W = 6.29 FT V 10 = 1.80 FPS T= Shear Stress Y= 62.4 PCF T= 0.046 PSF d= 0.05 FT S= 0.02 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.24 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 56.25 cf Hydraulic Retention = 3.96 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 4 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 FO.86 7.97 Q 1" Event = 0.34 cfs Q 10 year event= 2.74 cfs d = 0.060 ft (min. flow depth for 1"storm) A = 0.37 FT^2 d = 0.21 ft (for 10 year storm event) P = 6.38 FT n = 0.030 (computed) R = 0.06 8 = 6 ft (min. width) Q 1" Storm = 0.35 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.93 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 2.86 cfs Avg.S=l 0.015700 IftIft (avg. slope) W = 6.36 FT V 10 = 2.06 FPS T= Shear Stress Y= 62.4 PCF T= 0.059 PSF d= 0.06 FT S= 0.02 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.35 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 75.00 cf Hydraulic Retention = 3.61 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 5 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 F1.34 7.97 Q 1" Event = 0.54 cfs Q 10 year event= 4.27 cfs d = 0.080 ft (min. flow depth for 1"storm) A = 0.50 FT^2 d = 0.27 ft (for 10 year storm event) P = 6.51 FT n = 0.030 (computed) R = 0.08 8 = 6 ft (min. width) Q 1" Storm = 0.55 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 1.10 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 4.30 cfs Avg.S=l 0.015000 IftIft (avg. slope) W = 6.48 FT V 10 = 2.34 FPS T= Shear Stress Y= 62.4 PCF T= 0.075 PSF d= 0.08 FT S= 0.02 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.55 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 112.50 cf Hydraulic Retention = 3.42 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 6 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 FO.88 7.97 Q 1" Event = 0.35 cfs Q 10 year event= 2.81 cfs d = 0.090 ft (min. flow depth for 1"storm) A = 0.56 FT^2 d = 0.22 ft (for 10 year storm event) P = 6.57 FT n = 0.030 (computed) R = 0.09 8 = 6 ft (min. width) Q 1" Storm = 0.39 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.68 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 3.03 cfs Avg.S=l 0.005000 IftIft (avg. slope) W = 6.54 FT V 10 = 2.07 IFPS T= Shear Stress Y= 62.4 PCF T= 0.028 PSF d= 0.09 FT S= 0.01 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.39 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 75.00 cf Hydraulic Retention = 3.24 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 7 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 F5.81 7.97 Q 1" Event = 2.32 cfs Q 10 year event= 18.52 cfs d = 0.220 ft (min. flow depth for 1"storm) A = 1.47 FT^2 d = 0.7 ft (for 10 year storm event) P = 7.39 FT n = 0.030 (computed) R = 0.20 8 = 6 ft (min. width) Q 1" Storm = 2.47 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 1.69 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 18.76 cfs Avg.S=l 0.010000 IftIft (avg. slope) W = 7.32 FT V 10 = 3.31 FPS T= Shear Stress Y= 62.4 PCF T= 0.137 PSF d= 0.22 FT S= 0.01 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 2.47 cfs Swale Length =EEft If Available Depth (With 6" Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 431.25 cf Hydraulic Retention = 2.91 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 8A & 813 McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 F4.89 7.97 Q 1" Event = 1.96 cfs Q 10 year event= 15.59 cfs d = 0.310 ft (min. flow depth for 1"storm) A = 2.15 FT^2 d = 0.9$ ft (for 10 year storm event) P = 7.96 FT n = 0.030 (computed) R = 0.27 8 = 6 ft (min. width) Q 1" Storm = 1.99 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.93 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 15.61 cfs Avg.S=l 0.002000 IftIft (avg. slope) W = 7.86 FT V 10 = 1.78 IFPS T= Shear Stress Y= 62.4 PCF T= 0.039 PSF d= 0.31 FT S= 0.00 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 1.99 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 356.25 cf Hydraulic Retention = 2.98 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) OBJECTIVE: SOLUTIONS: RUNOFF CONDITIONS MAXIMUM Slope Condition SHEAR STRESS: CONVEYANCE AND TEMPORARY DIVERSION SWALE 9A & 9B McPhail Meadows Proposed Conveyance Swale Capacity Verify Capacity of Proposed Conveyance Swale Based Upon 1 in/hr event. Check that swale will non-erosively pass 10-year event Mannings Flow Equation c: I T (in/hr): A (ac): 1 10: 0.4 1.00 FO.54 7.97 Q 1" Event = 0.22 cfs Q 10 year event= 1.72 cfs d = 0.052 ft (min. flow depth for 1"storm) A = 0.32 FT^2 d = 0.18 ft (for 10 year storm event) P = 6.33 FT n = 0.030 (computed) R = 0.05 8 = 6 ft (min. width) Q 1" Storm = 0.22 CFS Z Left = 3 :1 (avg between culverts) V 1" Storm = 0.68 FPS Z Right = 3 :1 (avg between culverts) Q 10 year = 1.76 cfs Avg.S=l 0.010000 IftIft (avg. slope) W = 6.31 FT V 10 = 1.49 FPS T= Shear Stress Y= 62.4 PCF T= 0.032 PSF d= 0.05 FT S= 0.01 FT/FT RECOMMENDED LINING: Seed and Mulch With Contractor's Blend CHECK 1" STORM EVENT HYDRAULIC RETENTION TIME: Q 1" Storm = 0.22 cfs Swale Length = If Available Depth (With 6" EEft Freeboard)= Total Swale Depth = 1 ft TERMINOLOGY: Q = Peak Discharge,(CFS) V = Permissible Velocity, (FPS) d = Maximum Depth of Water, (FT) Vt = Trial Velocity, (FPS) n = Manning's "n" Coefficient V*R= Product of Velocity and Hydraulic Radius B= Bottom Width of Channel, (FT) Z = Side Slope of Channel (Z:1) Side Slope = 3.00 :1 Swale Capacity at Available Depth = 56.25 cf Hydraulic Retention = 4.31 minutes CHANNEL LINING: With velocities less than 2 f/s use Seed and Mulching With velocites greater than 2 f/s use Temporary Ditch Liner : if T I then use other lining A= Cross -Sectional Area of Flow, (FT^2) P = Wetted Perimeter of the Flow, (FT) R = Hydraulic Radius, (FT) S = Slope of the Channel, (FT/FT) Q = Discharge,(CFS) V= Velocity, (FPS) W = Top Width of Water in Channel, (FT) Y = Specific Weight of Water (62.4 PCF) TEMPORARY SEDIMENT TRAPS McPhail Meadows TEMPORARY SEDIMENT TRAP01 Design Storm Event Return Interval/Duration: 10 year �5 min. Post Watershed Size: 4.89 acres Disturbed Area: 3.83 acres Peak Discharge Rainfall Intensity: 7.970 in/hr Pre -Development c: 0.2 unimproved area Post -Development c: 0.4 residential -single family Q pre: 7.79 cfs Estimated Percent Impervious Area: 24 % Q post: 15.59 cfs Impervious Area: 1.174 acres Pervious Area: 3.716 acres Minimum Volume Requirement: 3,600 cf/acre of disturbed area Minimum Volume Required: 13,788 cf Minimum Surface Area Requirement: 435 sf/cfs of Q10 peak flow Minimum Surface Area Requirement: 6,781 sf Basin Sizing Top of Dam Elevation: 236.00 ft Depth of Sediment Storage Above Grade: 2.00 ft Crest of Spillway Elevation: 234.50 ft Meets Minimum 2' Storage Depth Above Grade Existing Grade: 232.50 ft Basin Bottom Length: 250.00 ft Basin Bottom Width: 6.50 ft Meets Minimum 2:1 L/W Ratio Excavation Depth Below Grade: 1.50 ft Meets Minimum Excavation Depth Below Grade Basin Width At Crest Elevation of Stone Spillway Outlet: 27.50 ft Side Slopes of Basin: 3.00 : 1 Surface Area At Crest Elevation of Spillway Outlet: I sf Meets Minimum Surface Area Requirements Bottom of Basin Elevation: 231.00 ft Surface Area of Basin Bottom: 1,625 sf Depth of Available Storage Below Crest of Spillway Outlet: 3.50 ft Available Storage Volume at Crest of Spillway Outlet: 14,875 cf Meets Minimum Volume Requirements Noff Spillway Design Qpeak: 15.59 cfs Depth of Flow Across Weir: 0.50 ft Meets Maximum 'Recommended' Flow Depth Weir Length: 15.00 ft Flow Capacity Across Weir: 15.91 cfs Meets Flow Capacity Requirement Spillway Crest Elevation: 234.50 ft Top of Dam Elevation: 236.00 ft Freeboard Provided: 1.00 ft Meets Minimum 'Recommended' Freeboard Sediment Cleanout Elevation: 232.75 ft Mark this elevation in the field McPhail Meadows Design Storm Event ReturnInterval/Duration: 10 year F5 min. Post Watershed Size: 2.45 acres Disturbed Area: 2.13 acres Peak Discharge Rainfall Intensity: 7.970 in/hr Pre -Development c: 0.2 unimproved area Post -Development c: 0.4 residential -single family Estimated Percent Impervious Area: 24 I mpervious Area: 0.588 acres Pervious Area: 1.862 acres Minimum Volume Requirement: 3,600 cf/acre of disturbed area Minimum Volume Required: 7,668 cf Minimum Surface Area Requirement: 435 sf/cfs of Q10 peak flow Minimum Surface Area Requirement: 3,398 sf Basin Top of Dam Elevation: 234.50 ft Depth of Sediment Storage Above Grade: 2.00 ft Crest of Spillway Elevation: 233.00 ft Existing Grade:M15 ft Basin Bottom Length:ft Basin Bottom Width:ft Excavation Depth Below Grade:ft Basin Width At CrestElevation of Stone Spillway Outlet: 25.50 ft Side Slopes of Basin: 3.00 : 1 Surface Area At Crest Elevation of Spillway Outlet: 3,h_. sf Bottom of Basin Elevation: 229.50 ft Surface Area of Basin Bottom: 0,675 sf Depth of Available Storage Below Crest of Spillway Outlet: 3.50 ft Available Storage Volume at Crest of Spillway Outlet: ' oT- cf Qpeak: 7.81 cfs Depth of Flow Across Weir: 0.50 ft Weir Length:1 8.00 Ift Flow Capacity Across Weir: 8.49 cfs Spillway Crest Elevation: 233.00 ft Top of Dam Elevation: 234.50 ft Freeboard Provided: 1.00 ft Sediment Cleanout Elevation: 231.25 ft TEMPORARY SEDIMENT TRAP 02 Q pre: 3.91 cfs Q post: 7.81 cfs Meets Minimum 2' Storage Depth Above Grade Meets Minimum 2:1 L/W Ratio Meets Minimum Excavation Depth Below Grade Meets Minimum Surface Area Requirements Meets Minimum Volume Requirements Meets Maximum 'Recommended' Flow Depth Meets Flow Capacity Requirement Meets Minimum 'Recommended'Freeboard Mark this elevation in the field McPhail Meadows TEMPORARY SEDIMENT TRAP 03 Design Storm Event Return Interval/Duration: 10 year F5 min. Post Watershed Size: 3.96 acres Disturbed Area: 3.77 acres Peak Discharge Rainfall Intensity: 7.970 in/hr Pre -Development c: 0.2 unimproved area Post -Development c: 0.4 residential -single family Q pre: 6.31 cfs Estimated Percent Impervious Area: 1 24 % Q post: 12.62 cfs Impervious Area: 0.950 acres Pervious Area: 3.010 acres Minimum Volume Requirement: 3,600 cf/acre of disturbed area Minimum Volume Required: 13,572 cf Minimum Surface Area Requirement: 435 sf/cfs of Q10 peak flow Minimum Surface Area Requirement: 5,492 sf Basin Sizin Top of Dam Elevation: 227.50 ft Depth of Sediment Storage Above Grade: 2.00 ft Crest of Spillway Elevation: 226.00 ft Meets Minimum 2'Storage Depth Above Grade Existing Grade: 224.00 ft Basin Bottom Length: 285.00 ft Basin Bottom Width: 4.00 ft Meets Minimum 2:1 L/W Ratio Excavation Depth Below Grade: 1.50 ft Meets Minimum Excavation Depth Below Grade Basin Width At Crest Elevation of Stone Spillway Outlet: 25.00 ft Side Slopes of Basin: 3.00 : 1 Surface Area At Crest Elevation of Spillway Outlet: 7,125 sf Meets Minimum Surface Area Requirements Bottom of Basin Elevation: 222.50 ft Surface Area of Basin Bottom: 1,140 sf Depth of Available Storage Below Crest of Spillway Outlet: 3.50 ft Available Storage Volume at Crest of Spillway Outlet: 14,464 cf Meets Minimum Volume Requirements Qpeak: 12.62 cfs Depth of Flow Across Weir: 0.50 ft Weir Length: 12.00 ft Flow Capacity Across Weir: 12.73 cfs Spillway Crest Elevation: 226.00 ft Top of Dam Elevation: 227.50 ft Freeboard Provided: 1.00 ft Sediment Cleanout Elevation: 224.25 Meets Maximum 'Recommended' Flow Depth Meets Flow Capacity Requirement Meets Minimum 'Recommended' Freeboard Mark this elevation in the field McPhail Meadows TEMPORARY SEDIMENT TRAP 04 Design Storm Event Return Interval/Duration: 10 year F5 min. Post Watershed Size: 4.75 acres Disturbed Area: 4.2 acres Peak Discharge Rainfall Intensity: 7.970 in/hr Pre -Development c: 0.2 unimproved area Post -Development c: 0.4 residential -single family Q pre: 7.57 cfs Estimated Percent Impervious Area: 1 24 % Q post: 15.14 cfs Impervious Area: 1.140 acres Pervious Area: 3.610 acres Minimum Volume Requirement: 3,600 cf/acre of disturbed area Minimum Volume Required: 15,120 cf Minimum Surface Area Requirement: 435 sf/cfs of Q10 peak flow Minimum Surface Area Requirement: 6,587 sf Basin Sizin Top of Dam Elevation: 231.50 ft Depth of Sediment Storage Above Grade: 2.00 ft Crest of Spillway Elevation: 230.00 ft Meets Minimum 2'Storage Depth Above Grade Existing Grade: 228.00 ft Basin Bottom Length: 115.00 ft Basin Bottom Width: 45.00 ft Meets Minimum 2:1 L/W Ratio Excavation Depth Below Grade: 1.50 ft Meets Minimum Excavation Depth Below Grade Basin Width At Crest Elevation of Stone Spillway Outlet: 59.00 ft Side Slopes of Basin: 2.00 : 1 Surface Area At Crest Elevation of Spillway Outlet: 6,785 sf Meets Minimum Surface Area Requirements Bottom of Basin Elevation: 226.50 ft Surface Area of Basin Bottom: 5,175 sf Depth of Available Storage Below Crest of Spillway Outlet: 3.50 ft Available Storage Volume at Crest of Spillway Outlet: 20,930 cf Meets Minimum Volume Requirements Qpeak: 15.14 cfs Depth of Flow Across Weir: 0.50 ft Weir Length: 15.00 ft Flow Capacity Across Weir: 15.91 cfs Spillway Crest Elevation: 230.00 ft Top of Dam Elevation: 231.50 ft Freeboard Provided: 1.00 ft Sediment Cleanout Elevation: 228.25 Meets Maximum 'Recommended' Flow Depth Meets Flow Capacity Requirement Meets Minimum 'Recommended' Freeboard Mark this elevation in the field