Rainfall rates for successive 20-minute periods of a 140-minute storm are 1.5, 1.5, 6.0, 4.0, 1.0, 0.8, and 3.2 inches/hour, totaling 6.0 inches. determine runoff during successive 20-minute periods by the nrcs method (i. e. curve number method). the soil in the basin belongs to group a. it is an agricultural row cropland with contoured pattern in good hydrologic condition. the soil is in average condition before the storm (moisture condition iii). (10 points)