CIV E 445 - APPLIED HYDROLOGY
SPRING 2010
SOLUTION TO HOMEWORK 1, CHAPTER 1

Problem 1-1

The mean annual flow in mm is:

Q = [ 5.2 m3/s • 86,400 s/d • 365 d/y • 1000 mm/m ] / [ 709 km2 • (1000 m/km)2 ] = 231.29 mm/y

The precipitation depth abstracted by the catchment is: (750 - 231.29) = 518.71 mm/y.   ANSWER.

The runoff coefficient K = 231.29 / 750 = 0.308 ≅ 0.31  ANSWER.

Problem 1-2

The mean annual flow is:

Q = [ 30.5 ft3/s • 86,400 s/d • 365 d/y] / [ 182 mi2 • (5280 ft/mi)2 ] = 0.1895 ft/y = 2.27 in/y

The precipitation depth abstracted by the catchment is: (15 - 2.27) = 12.73 in/y.   ANSWER.

The runoff coefficient K = 2.27 / 15 = 0.151 ≅ 0.15  ANSWER.