53:119 Hydrology
Problem #27
Unit Hydrograph Derivation by Back Substitution

Hydrograph analysis of an extreme flood event on a 6.97 mi2 watershed indicated that the rainfall excess pattern was:

Time (hours)

0-2

2-4

4-6

Pe (in)

0.43

1.77

2.81

and the direct runoff hydrgraph was:

Time (hours)

0

1

2

3

4

5

6

7

8

9 10 11 12
DRH (cfs)

0

105

207

516

852

1700

1851

2538 1673 956 363 169 0

Use this information to determine the 2-hour unit hydrograph for the watershed by back substititution.

  1. Set up the set of deconvolution equations to predict the direct runoff hydrograph using the terms u0, u1, ..., un, for the unknown 2-hour unit hydrograph values.
  2. Solve the deconvolution equations using back substitution

Last changed on 10/28/13 by aab.