(Solved): (c) To use the unit hydrograph above to estimate the hydrograph for a \( 30 \mathrm{~min} \) rainf ...

(c) To use the unit hydrograph above to estimate the hydrograph for a \( 30 \mathrm{~min} \) rainfall excess of \( 12.6 \mathrm{~cm} \), the total hydrograph is estimated as the sum of two hydrographs, one starting at \( 0 \mathrm{~min} \) and one starting at \( 15 \mathrm{~min} \). What is the rainfall excess used for the first storm? Solution: \( 6.3 \mathrm{~cm} \).