WSP01998

• File Number: 5970
• Description: Flood Protection Section - Miscellaneous Reports
• State: CO
• Basin: Statewide
• Date: 12/1/1972
• Author: CSU
• Title: Theory and Experiments in the Prediction of Small Watershed Response - Completion Report Series Number 42
• Water Supply Pro - Doc Type: Report/Study

001246

9

K = S_
- Q -

-~
dQ
dt

The value of

K was found from a semi-log graph of the recession side

of a hydrograph using the relationship:

K - -

t - t
o
1nQt - 1nQt

Kavvas (1972) found that the Clark method produced a reasonable

unit hydrograph from observed floods on small watersheds. (See Fig. 2

for an example). It was also found that an observed hydrograph from

the experimental watershed could be reproduced using the Clark time-area

method.

CONCLUSIONS

This investigation has shown that the hydrograph of runoff could

be computed for a relatively simple watershed by method based on the

Kinematic Wave Theory (Woo1hiser et al, 1971), The uncertainty in

applying this procedure is associated with the selection of the flow

regime and the selection of the appropriate friction factor (Schulz and

Fawkes, 1972).

For a large diverse natural watershed, the synthetic unit hydro-

graph can be used for obtaining a flood hydrograph. (Schulz et a1, 1971).

When radical changes take place in the watershed, changes in the unit

hydrograph can be predicted using estimates of the response time in the

altered watershed. (Van Sickle, 1962 and Moore and Morgan, 1969).

The CSU Experimental Rainfall-Runoff Facility can be used to study

intimate details of the hydraulics of the overland flow (Correia, 1972

and Fawkes, 1972).