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HomeMy WebLinkAbout1.16 Drainage CalculationsAppendix B 1 Drainage Calculations 105 Lot 1 Coverage Existing Lot 1 Coverage Type of Site Coverage Area (square feet) Area (acres) Gambel Oak Mixed Montane Shrublandl 157,687.00 3.62 Mountain Big Sagebrush Dominated Shrublandl 271,814.00 6.24 Existing Graveled Access Roadl 6,098.00 0.14 Lot 1 Development Scenario Coverage Type of Site Coverage Area (square feet) Area (acres) Gambel Oak Mixed Montane Shrubland 157,687.00 3.62 Mountain Big Sagebrush Dominated Shrubland 254,114.00 5.83 Existing Graveled Access Road 6,098.00 0.14 Graveled Driveway/Parking Area 9,200.00 0.21 Single Dwelling Unit 3,500.00 0.08 Landscape Area 5,000.00 0.11 Time of Concentration Overland Sheet Flow Manning's Roughness Coefficient (n) Sheet flow length, feet (1) 2 -year, 24-hour rainfall, inches (P) Slope of land surface, feet/feet (S) Maximum Sheet Flow Length (I) I = (100*SQRT(S))/n I = (100*SQRT(0.086))/0.150 I = 195.08 Travel time, hour = 0.249 Travel time, minutes = 14.967 Shallow Concentrated Flow Slope of land surface, feet/feet (5) Velocity, feet/second Travel time, hour = 0.216 Travel time, minutes = 12.967 Time of concentration (Tc), hour = 0.465 Time of concentration (Tc), minutes = 27.934 0.150 195.08 1.248 0.086 0.086 Meadows, Pastures and Range Land 0.8 Forest with Heavy Ground Litter and Meadow Rational Method Drainage Calculations (4=CiA) Existing Conditions Type of Site Coverage Area (square feet) Area (acres) Runoff Coefficient' Weighted Runoff Coefficient (C) Gambel Oak Mixed Montane Shrublandl 157,687.00 3.62 0.5 0.18100 Mountain Big Sagebrush Dominated Shrublandl 271,814.00 6.24 0.42 0.26208 Existing Graveled Access Road" 6,098.00 0.14 0.8 0.01120 Graveled Driveway/Parking Area 0.45428 1Runoff coefficients were obtained from the NRCS's Hydrology Training Series - Peak Discharge (Other Methods) Study Guide. Development Scenario Conditions Type of Site Coverage Area (square feet) Area (acres) Runoff Coefficient' Weighted Runoff Coefficient (C) Gambel Oak Mixed Montane Shrubland 157,687.00 3.62 0.5 0.18100 Mountain Big Sagebrush Dominated Shrubland 253,314.00 5.83 0.42 0.24501 Existing Graveled Access Road 6,098.00 0.14 0.8 0.01120 Graveled Driveway/Parking Area 9,200.00 0.21 0.8 0.01690 Single Dwelling Unit 3,500.00 0.08 0.5 0.00402 Landscape Area 5,000.00 0.11 0.25 0.00287 Conditions 0.46100 "Runoff coefficients were obtained from the NRCS's Hydrology Training Series - Peak Discharge (Other Methods) Study Guide. Rainfall Intensity (i) at 711 2 -YR Runoff (inches/hour) 5 -YR Runoff (inches/hour) 10 -YR Runoff (inches/hour) 25 -YR Runoff (inches/hour) 50 -YR Runoff (inches/hour) 100 -YR Runoff (inches/hour) 0.804 1.18 1.47 1.85 2.12 2.38 "Point precipitation frequency estimates for the lot were obtained from NOAA's National Weather Service - Hydrometeorological Design Studies Center. Drainage Basin Area (A), in acres 10.00 Change in Drainage Basin Runoff 1cfs = cubic feet per second 2 -YR Runoff (cfsl) 5 -YR Runoff (cfsl) 10 -YR Runoff (cfsl) 25 -YR Runoff (cfsl) 50 -YR Runoff (cfsl) 100 -YR Runoff (cfsl) Existing 3.652 5.361 6.678 8.404 9.631 10.812 Conditions Development Scenario 3.706 5.440 6.777 8.528 9.773 10.972 Conditions Difference 0.054 0.079 0.099 0.124 0.142 0.160 (1.48%) (1.48%) (1.48%) (1.48%) (1.48%) (1.48%) 1cfs = cubic feet per second Map of Lot 1 Development Scenario ` /r oci' // I / 1 f' , ' ,.:' ;`+'• `,' `,`_` , - - -- - sd -19:- :5 \, ' , --3-- A,. 1. X59--P53g_c ._ 22— ..-//---1-7�- //// /r , / 2 ,,,^� ri tet' — — �� — — — — 1.� - �� . -.,r - -'�5�. _'T5z@ — ` - — - �`= - i J ` r ' f / �� 7510 '_ , ,���=_� _ _� m_,=��; ' -' - GAMBEL OAK` . _ 1 r1. ' MOUNTAIN B1G. MIXED MONTANE' Al,' SAGEaRIJSH SHRUBLAND I `, `, y` BUILDING AREA yy ' ,�OMINATED5.83 AC ,. r,I. , ; SHdtUBLANG '- ` 0.6.8 -AC `,.�`I r ' Ii4.' • -749.5- rt , / . btu'- - r l I, 1 l' ii 1', `, ,', GRAVELED DRIVEWAY ** \ 11`` , 7 , '.& PARKING AREA \\�\ `-'rte ,1 , �, \ \ , , , 0.21 AC \.� _ ,, \ t ''-_,1455 '� �� • _\ t 100` WELL; `.r I` 011,; ' , ', 1 t--`-----7456- BUFFER 11 . I Ij, L ; EXISTING GRAVELED i 1 I 1 ACCESS ROAD - �- ' 0.14 AC �`;' '� 7 j it 1-. ' ' ' ‘i \ :04: , �` .\ `/ WELL r�1{ ' \,` , 1 , h�:',,.,-o ' I'`' ',+ S. .1. '1, ••• V!. ;'as``7426 _ +, , , , p.% `/ •47} i ® ti \f�E�`1. b 14. I ! q �_ - z_vz7470 , :j ., r�- . — , \ \ , f i ! , �, ®�0 .� :, r t, —� 1�T 1 _ i1 , 1 1 \, 11 f I II i I 2 \ / d f/ / I 1 `�``, ', `, `, , , f l ! r I , r r + I 1 v♦ 1 ,\ A. ` f // r 1 2. ,' r/ ` ``1 \1 ,. ', I 1, 'I •I 1 •1 rr / ' 11 11 `, `4l\ I \� \J I , I/ / /' 1 I A -I I 1 I 1 c / 1 s , 1 a \ • t I i �ttr�y y! m .�, rl 1 i ,, , I , r / r f/ r I t'f t , , , �c ir I y/R' ry, ^� r f r // r/ / / I I %\ / t 1 c, 1 I 1 n / / rf , r \\ 1t „ , \t 1 �\ \ 1 \▪ \ r .\ \• \ \, • I\ l Source: Esri. DigitalGlobe, GeoEye, Earthstar Geographies, CNES/Airbus DS, USDA, USGS, AeroGRID.IIGN. and the GIS U1ser II Community 108 Manning's Roughness Coefficients (n) for Overland Sheet Flow Hvdrologv 7-F-5 or a distance of 300 feet. The overland sheet flow velocity is usually slower than the velocities further downstream. The kinematic wave equation can be used to estimate the time of concentration associated with overland sheet flow. The equation is shown below, and it is only applicable for travel 0,93(1-.° 6 T,_r (Equation 4) distances equal to or less than 300 feet. W here: Tasf Travel time for the overland sheet flow segment in minutes (min.) L — Length of the overland sheet flow segment in feet (ft) n = Manning's roughness coefficient (See Table 3) i = Rainfall intensity in inches per hour (in/hr) See Appendix A, S = The average slope of the overland area in feet per feet (ft/ft) Note: Calculating the time of concentration, for overland sheet. flow is an iterative or trial and error solution because both the flow time and the rainfall rnlensity are unknown. The procedure is illustrated in the Example. Table 3 Manning's Roughness Coefficients Tor Overland Sheet Flow (Maximum Flow Depth = 1 inch) Pavement & Roofs City Business Areas Graveled Surfaces Apartment Dwelling Areas Industrial Areas Urban Residential Areas (more than 6 units acre) 0.014 0.014 0.020 0.050 0.050 0.080 Meadows, Pastures & Range Land 0.150 Rural Residential Areas (more than 6 units acre) Playgrounds, Light Turf Parks & Cemeteries, Heavy Turf Woodland & Forests 0.240 0.240 0.400 0.400 • Shallow Concentrated Flow - Overland sheet flow often becomes either shallow concentrated flow or open -channel flow as it progresses down the drainage. It becomes ODOT Hydraulics Manual 109 Shallow Concentrated Flow Velocities (V) I i} dmlug 7-F-7 WATERCOURSE SLOPE IN PERCENT 50 40 30 10 5 3 2 .6 .3 2 .1 .2 .3 .6 1 2 3 5 10 20 .1 .2 .3 .5 1 2 VELOCITY, V (Ft. / Soc.} 5 Figure 1 Shallow Concentrated Flow Velocities 10 50 40 30 20 10 5 3 2 1 5 2 .2 •1 20 ODOT Hydraulics Manual Runoff Coefficients (C) from the NRCS Hydrology Training Series - Peak Discharge (Other Methods) Study Guide TABLE 1 1'aloes of Rum) Coefficient C URBAN AREAS: Type of drainage area Runoff coefficient C Open Sandy Loam Clay. and Silt Loam Lawns: 0,05 - 0,10 Sandy soil. flat 2% Sandy soil. average. 2 - 7% 0.10 - 0.15 Sandy soil, steep, 7% 0.15 - 0.20 Heavy soil flat. 2% 0,13-0.17 Hear soil. average. 2 - 7% 0.35 Heavy sail. steep. 7% 0.18 - 0,22 0.30 0.25 - 0,35 Business: 0,70 - 0.95 Downtown areas Neighborhood areas 0,50,0.70 Residential; 0,30 - 0.5(1 Single-family areas 0.40 - 0.60 Multi units. detached Multi units. 0,60 - 0.75 attached Suburban 0,25 -0.40 Aparunent dwelling areas 0.50 - 0.70 Industrial: 0.42 Light areas 0,50 - 0.80 Heavy areas 0.60 -11.911 Parks. cemeteries 0.10 - 0.25 Playgrounds 0.20 - 0.35 Railroad yard areas 0,20 - 0.40 Unimproved areas 0,10 - 0.30 Streets: 0,70 -0.95 Asphaltic 0.80 - 0.95 Concrete 0.70 -0 85 Brick Drives and walks 0,75 - 0,85 Roofs 0.75 - 0.95 AGRICULTURAL AREAS: Topography and Vegetation Runoff Coefficient C Soo Texture Soil Texture Open Sandy Loam Clay. and Silt Loam Tight Clay Woodland Rat 0-5%Slope 0.10 030 0.40 Rolling 5 - 10% Slope 0,25 0.35 030 Hilly 111- 30% Slope 0.30 0.50 0.60 Pasture 0,10 0.30 0,40 Plat 0.16 0,36 0.55 Rolling Hilly 0.22 0.42 0.60 Cultivated Flat 0,30 0.50 0.60 Railing 0.40 0,60 0.70 Hilly 0.52 0.72 0.82 Generated by a Trial Version of NetCentric Technologies Common Look® Acrobat® Plug-in www.net-centric.com 111 Point Precipitation Frequency Estimates (i) from NOAA's National Weather Service - Hydrometeorological Design Studies Center 11/16/2018 Precipitation Frequency Data Server NOAA Atlas 14, Volume 8, Version 2 Location name: Carbondale, Colorado, USA' Latitude: 39.4864°, Longitude: -107.1198° Elevation: 7476.52 ft" - source: ESRI Maps ^ source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Senja Pence, Deborah Martin, Sandra Pavlovle, Ishan Roy, Micheer 5t. Laurent. Oen Trypetuk. Dale Unruh. Michael Yekta, Geolery Bonnin NOW, Nadcnal Weather Seance, Silver5pneg, Maryland PF tabular I PF graphical Maps & aerials PF tabular PDS -based point precipitation frequency estimates with 90% confidence intervals (in incheslhour)1 Average recurrence Interval (yeas} Duration 1 2 5 10 25 50 100 200 500 1000 1.40 2.08 3.14 3.90 5.10 5.90 6.67 7.42 8.34 0.00 (1.14-1.80) (1.68-266) (252-4.03) 0.16-5.15) (3.85-8.79) (437-503) (4-74-9.37) 0.03-10.81 (5.41-12.6) (530-14.0) 10 -Min 1.03 (0.834-1.31) 1.52 (1.23-1.95) 2.30 (1.85-2.95) 2.92 (2333.77) 3.73 (2.824.97) 4.33 (3.19.5.88) 4.89 (3.47-8.86) 5.44 (3.68-7.91) 6.11 A3.96-922) 6.59 (4.17-10.2) 15N11ln 0.836 1.24 1.67 2.38 3.03 3.52 3.98 4.42 4.97 5.36 (0.676-1.07) (0996-1.58) (1.50-2.40) (1.89-3.06) (2.29-4.04) _(2.804.76) 2.82-5.58 (2.99-6.43) (322-7.50) (3.39-0.31) 30-rnIn 0.668 (0.458-0.724) 0.804 (0.646-1.03). 1.18 (0.944-1.51) 1.47 (1.17-1-89) 1.85 (1.40-2.46) 2.12 (1.57.2.88) 2.38 (1.69.3.34) 2.83 2.93 (1.78-3.52) (1.99-4.87) 3.14 • 6D loin 0.374 (0.301-0.477) 0.495 (0.399-0.6321 0.685 (0.550-0.8791 0.836 (0.666-1.08) 1.03 (0.782.1.37) . 1.18 (0.870-1.60) 1.31 (0.933-1.84) x(1.90-4.42) 1.44 1.60 (0.976-2.10) (1.042.42) 1.71 (1.08-2.66) 2 -hr 0.232 0.294 0.392 0.460 0.570 0.645 0.716 0.784 0.068 0.928 {0.189.0.292) (0.239-0.371) (0.318-0.496) (0.376-0.598) (0.438-0.750) (0.482-0.665) (0.515.0.991) (0.537-1.12) (0.569-1.29) (0594-1.42) 3 -hr 0.180 0.216 0.278 0.327 0.392 0.440 0.487 0.532 0.590 0.833 (0.148-0.225) (0.178-0.273) (0.227-0.350) (0.285-0.413) (0.303-5512) •.332-0586) (0.353-0.689) (0.366-0.759) (0.390-0.672) (0.407-0.956) 0 -hr 0.11e (0.008-0,148) 0.135 (0.111-0.156L 0.162 (0.133-0.201) 0.185 (0.151-0.231) 0.216 (0.172-0.263) 0.244 (0.187-0.323) 0.271 (0.2000.370) 0.299 (0.210-0.423) 0.337 (0.2264.494) 0.367 (0.230-0.547) 12 -hr 0.074 (0.062-0.091) 0.084 (0.070-0.103) 0.101 (0.084-0124) 0.116 (0.096.0.142) 0.137 (0.109-9.176.1 0.154 (0.120-0.202) 0.172 (0.128-0.233) 0.191 (,0.136-0.268) 0.215 (0.148-0.315) 0.239 (0.157-0.351) 24 -hr 0.046 0.052 0.063 0.073 0.087 0.099 0.111 0.124 0.142 0.156 (0.039.0.055)-(0.044-0.063) (0.053-0.077) (0.061-0.089) (0.071-0.111) (0,078-0.128) (0.084-0.148) (0.089-0.171) (0.097-0.202) (0.104-0.226) 0.028 0.031 0.036 0.044 0.053 0.060 0.068 0.076 0.085 0.005 (0.0240.033) (0.027-0.037} (0.033-0.048) (0.037-0.053) (0.043-9067) (0,048-0.077) (0.051-9089) (0.055-0.102) (0.060-0.121) (0.064-0.136) 3-day0.021 0.024 (0.018-0.024) (0.020.8028) 0.029 (0.025-0.034) 0.033 (0.028-0.039) 0.040 (0.032-0.049) 0.045 (0.036-0.056) 0.050 (0.038-0.065) 0.056 (0.041-0.075) 0.064 (0.044-0.088) 0.070 (0.047-0.096) 4d� 0.017 0.019 0.023 0.027 0.032 0.036 0.040 0.045 0.051 0.055 (0.015-0.620) (0.017-0.023) (0.020-0.028) (0.023-0.032) (0.026-0.039) (0.029-0.045) (0-031-0.052) (0.033-0.059) (0.035-0.070) (0.038-0.078) Tway 0.012 0.013 (0.0100.014) (0.012-0.015) 0.016 (0.014-0.018) 0.010 (0.015-0.021) 0.021 (0.017-0.026) 0.023 (0.019-0.029) 0.026 (0.020.0.033) 0.029 (0.021-0.038) 0.032 (0.0234.044) 0.035 (0.024-0.048) 10•day 0.010 0.011 0.013 0.014 0.016 0.010 0.020 0.022 0.024 0.026 (0.008-D.011) {0.009-0.012) (0.011-0.014) (0.012-0.018) (0.014-0.020) (0.015-0.022) 0-016-0.025 0.016-0.028 (0.017-0.033) .10.018-0.035) 0.007 0.007 0.000 0.000 0.011 0.012 0.013 0.014 0.016 9.017 ?D�itry (0.0013-0.0071 (0.006-0.008) (0.007-0.010) (0.008-0.011) (0.000-0.013) 0.0100.014) (0.010.0.016) (50114.016) (0.011-0.021) (0.012.0.022) 30 -day 0.005 0.006 (0.005-0.008) (0.005-0.007) 0.007 (0.008-0.008) 0.006 (0.007-0.009) 0.009 (0.007-0.010), 0.010 (0.008-0.011) 0.010 (0.009-0.013) 0.011 (0.006-0.014) 0.012 (0.008-0.016) 0.013 (0.009-0.016) 0.064 0.005 0.006 0.006 0.007 0.000 0.009 0.009 0.010 0.011 45�day (0.0040.005) (0.004-0.006) (0.005-0.006) (0.006-0.007) (0.006-0.008) (0.007-0.009) (0.001-6.010) (0.807-0.011) (0.007-0.013) (0.007-0.014) �� ay 0.004 0.004 (0003-0.004)] OA04-0.0Wt� 0.005 0.006 .005-0.006 80.005-0.0061 0.006 0.007 1(0.005-90071 (0.006-0.008)] 0.007 (0.006-0.009)! 0.008 .006-0.010 0.009 0.009 (0.000-0.011)] (0.006-0.012) 1 Precipital on 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 gken duration and average recurrence interval) will he greater than the upper bound (or less than the lower hound) is 5%. Fslimeles at upper bounds ere not checked against probable maximum preapita5on (PMR) estimates and may be higher than currently valid PMP values. Please refer to NOM Atlas 14 document For more irdannation, Back to Top PF graphical https://hdsc.nws.noxa.govthdec/pfdslpfds_prIntpage.html7lat 39.4864&Ion=-107.1196&data=lntens8y&units=english&series=pds#table 1/4 112 11/16/2018 Precipitation intensity (in/hr) Precipitation intensity (inlhr) 10.000 1.000 0.100 0.010 0.001 10.000 1.000 0.100 0.010 0.001 1 Precipitation Frequency Data Server PDS -based intensity -duration -frequency (PDF) curves Latitude- 39.4864°, Longitude: -107.1198° E Cr c E .c .0 N A .c T ?.7. r MI 1r0 -0'V Duration }. a. ?.7 a ra ro ra . -0 -0 0 r v50 5 10 25 50 100 200 NOAA Atlas 14, Volume 8, Version 2 Average recurrence interval (years) 500 1000 Created (GMT): Sat Nov 17 04:36:54 2018 Back to Toia Maps & aerials Small scale terrain Average recurrence internal (years) — 1 2 5 10 25 50 100 200 500 1000 Duration — 5 -min — 2 -day — 1(1 -min — 3 -day 15 -min -- 4 -day — 30-4rn — 7 -day — 60 -Mn — 10 -day — 2 -hr — 20 -day — 3 -hr — 30 -day — e -hr — 45 -day — 12 -hr — 60 -day — 24 -hr https//hdsc.nws.noaa.govlhdsdpfdslpfds_printpage.html?let=39.4864&Ian=-107.1198&data=intensity&units=english&series=pds#table 2/4 113