CIV E 445 - APPLIED HYDROLOGY
SPRING 2011
SOLUTION TO HOMEWORK 1, CHAPTER 1

Problem 1-1

The mean annual flow in mm is:

Q = [ 5.45 m3/s • 86,400 s/d • 365 d/y • 1000 mm/m ] / [ 719 km2 • (1000 m/km)2 ] = 239.04 mm/y

The precipitation depth abstracted by the catchment is: (785 - 239.04) = 545.96 mm/y.   ANSWER.

The runoff coefficient K = 239.04 / 785 = 0.3045 ≅ 0.3  ANSWER.

Problem 1-2

The mean annual flow is:

Q = [ 33 ft3/s • 86,400 s/d • 365 d/y] / [ 193 mi2 • (5280 ft/mi)2 ] = 0.1934 ft/y = 2.32 in/y

The precipitation depth abstracted by the catchment is: (16 - 2.32) = 13.68 in/y.   ANSWER.

The runoff coefficient K = 2.32 / 16 = 0.145 ≅ 0.15  ANSWER.