CIV E 445 - APPLIED HYDROLOGY
SPRING 2011
HOMEWORK 6, CHAPTER 5

Problem 6-1

Given P = 7 in, and CN = 85, find the runoff Q (in). Verify using Online curve number.

Problem 6-2

Given the following 2-h unit hydrograph for a certain catchment, find the 3-h unit hydrograph.

Time
(h)
Flow
(m3/s)
00
130
280
3100
470
530
610
70

Using this unit hydrograph, calculate the 1-h unit hydrograph. Verify using Online S-hydrograph.

Problem 6-3

The following 2-h unit hydrograph has been developed for a certain catchment:

Time
(h)
Flow
(ft3/s)
00
2100
4200
670
850
1030
120

A 6-h storm covers the entire catchment and is distributed in time as follows:

Time
(h)
Total
rainfall
(in/h)
0-21.0
2-42.0
4-61.5

Calculate the composite hydrograph for the effective storm pattern, assuming a runoff curve number CN = 84. Verify using Online convolution.

Problem 6-4

A certain basin has the following 2-h unit hydrograph:

Time
(h)
Flow
(m3/s)
00
15
220
335
465
590
670
755
840
920
1010
110

Calculate the flood hydrograph for the following effective rainfall hyetograph (CN = 100):

Time
(h)
Effective
rainfall
(cm/h)
0-31.3
3-62.2

Verify using Online S-hydrograph and Online convolution.