Extracted text: A watershed with approximately 480 acres has the time-area relationship between its sub-basins and the outlet as shown in Table 1. Direct runoff calculated using the Time-Area method for a rainfall event is given in Figure 1. The o index of 0.5 in/hr and a depression storage of 1 ir be assumed. Considering that the gross rainfall rate was always more than or equal to the in. 1/P rate, a) calculate and plot the excess rainfall hyetograph and the gross rainfall mass curve, and b) estimate the lag-time and the time of rise. 400 Table 1: Time-area relation 340 300 300 Time Area (hr) (ас) 200 1 70 200 180 2 200 105 3 180 100 1 3 4 Time interval (hr) Direct runoff (cfs)