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TABLE 2 <br /> TIME OF CONCENTRATION <br /> Sub- linifial Subarea(TR-55 Method) Shallow Concentrated Flow Flax Caics Flow In Natural Surface Channels To= <br /> Basin Lis n PZ Tc� <br /> f1 flL s v Toa Area Duration I Q UIS£I. DIS EI. L= B T D N V Tc2 Toy+Ta2+Tcy <br /> /ft in. m€n ft Rift j ftlsec min acres I min inlhr efs ft It ft ft ft fUsec min min hours <br /> �1 2 (3 �4 25 5 21 22 23) (24 6) 8) 9 10) 11 12} 13 14 15 16) 1 18 f19) 0 <br /> 1A 300 0.042 0.15 1.19 29 1700 0.06 3.8 7.37 184.18 14.9 1.72 155.07 500 270 6160 10 10 1.075 1 6.90 14.89 51 6.85 <br /> 1 B 300 0.048 0.15 1.19 27 1150 0.05 3.6 5.37 263.12 14.8 1.73 222.43 540 270 6890 10 10 1.275 1 7.77 14.78 47 0.79 <br /> (1)Watershed or Sub-Basin Ill (12) L2=Length of natural flow channel <br /> (2) L=Length of initial area flow path(assumed) (13) 8=Approximate bottom width of natural channel <br /> (3) s-Approx.slope along flow path (14)Z=Inverse of channel side slope <br /> (4) n- 0.15 short prairie grass" (15) D=Depth of Bow <br /> (16) N=Number of flow channels <br /> (5)Time of concentration in minutes for sheet flaw=0.007K)0'6I(P20 b SGA). - (17)V a Flaw velocity in natural channel- <br /> (6)Watershed or Sub-Basin area (18) Tcn=Time of cancentratlon for flow In natural surface channels <br /> (7)Assumed precipitation intensily duration(Verified approx.by talcs in cal.18) (19)Time of Concentration(minutes) <br /> (6) Precipitation Intensity for 100-year,24 hour storm for (20)Time of Concentration(hours) <br /> duration equal to the assumed time of concentration (21) Shallow Concentrated Flora Length <br /> (9)Runoff based an rational formula: (22)Slope along flow path <br /> Q=CIA• (23)Velocity based on TR-55.Figure 3.1 Equation Fit to Data v=15.957(S)0.4966 <br /> C=Runoff Coeff.-0.49 tot PasturelRenge" (24)Tcs-Time of Concentration for shallow concentrated flow' <br /> I =Precipitation intensity,inches/hr (25) Two-Year,24-Hour Rainfall Depth <br /> A =Sub-Basin area,acres <br /> (The above formula is used to compute To only.The <br /> basin flood routing analysis is computed using NEC-1) <br /> (10) Upstream Channel Invert Elevation <br /> (11) Downstream Channel Invert Elevation <br /> "TR-55 <br /> •' AppiledHydrology,Chow,Maldment,and Mays,1988 <br /> N-.W104L1hydrologylTlme of Cone 0104L.As <br />