Using the rational method and the following rainfall IDF curves, estimate the 100-yr runoff from a 150-acre watershed covered by single-family residential land use.
The dimensions for computing time of concentration are:
Sheet flow Length:
200 ft Surface description:
dense grass Manning roughness coefficient:
0.242-yr 24-hr rainfall:
4.2 in Slope:
0.08 ft/ft Shallow concentrated flow Length:
2000 ftSurface description:
unpavedSlope:
0.2 ft/ftChannel flowLength:
4500 ftVelocity: 7 ft/sec