53:078 Principles of Hydrology (Spring 2004)
Problem #16
Direct Runoff Hydrograph Prediction Using a Unit Hydrograph
The 1-hour unit hydrograph for a 0.635 mi2 catchment is given
below.
| Time (min) |
1-hour UH (cfs) |
| 0 |
0.0 |
| 30 |
10.6 |
| 60 |
24.7 |
| 90 |
49.4 |
| 120 |
74.2 |
| 150 |
98.9 |
| 180 |
113.0 |
| 210 |
102.4 |
| 240 |
91.8 |
| 270 |
77.7 |
| 300 |
56.5 |
| 330 |
42.4 |
| 360 |
31.8 |
| 390 |
23.0 |
| 420 |
12.4 |
| 450 |
7.1 |
| 480 |
3.5 |
| 510 |
0.0 |
- Determine the volume of direct runoff Vd (in acre-feet)
of the unit hydrograph.
- Determine the depth of direct runoff rd (in inches) for
the unit hydrograph. Verify that the unit hydrograph is consistent with
1-inch of rainfall excess (i.e., a property of a unit hydrograph).
- Estimate the direct runoff hydrograph (in cfs) for a 1-hour period with
rainfall excess of 2.8 in.
- Estimate the direct runoff hydrograph (in cfs) for a 1-hour period with
rainfall excess of 1.6 in, followed by a 1-hour period with rainfall excess of
1.2 in.
Last changed on
03/22/04
by aab.