Q. A bridge is to be constructed over a stream having a catchment area = 20 miles2 partly in plains and partly in hills. Portion in hills has a length of 1.7 miles and fall of 880 ft. and that in plains has a length of 5.7 miles and a fall of 244 ft. Calculate the flood discharge if co elf of discharge is 80 % and area factor 95 5 and value of constant for calculating time of concentration = 14 for hills and 6 for plains. One hr rain fall intensity may be assumed as 2.5''.