A pine forest is to be cleared for a commercial development. The IDF function for a $20-$yr return period is given by The storage capacity of the trees is estimated as $6$ mm$,$ the leaf area index is $7,$ and the evaporation during the design rainfall event is estimated as $0\mathrm{.}2$ mm$/$hr$.$ a$)$ Determine the increase in rainfall reaching the ground during a $20-$min rainfall event b$)$ Compare the results will the interception predicted by Horton$-$type equation