Consider a catchment that has a total area of 2.1 acres. Runoff from the entire catchment flows into one pipe inlet. Part of the
catchment is a softball field (1.5 ac) and the other part is a set of paved tennis courts (0.6 ac). The softball field has a C value of 0.3 and a time of concentration of 7 minutes, and the paved area has a C value of 0.95 and a time of concentration of 2 minutes. The IDF curve is given by i =100/(tc + 10) where i is in in/hr and tc is in minutes. Determine the design storm intensity and flow rate for the following cases: (a) The usual method based on the entire drainage area contributing to flow. (b) A modified method that assumes that only the paved tennis courts contribute to flow. (c) A different modified method that assumes a time of concentration of 2 minutes, and an approximation that the entire tennis court region contributes flow and 2/7 of the softball region contributes flow. Comment on the results and their impact on design. Is it always best to use method (a)
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