Maximum Peak Flow Research Articles

Water yield, annual peaks and exposure in mountainous terrain

In steep, mountainous terrain of the western United States, where summer rains are negligible and annual runoff is primarily dependent on melting snow, the runoff distribution is such that a high energy recipient (HE) watershed generally yields more water per unit area than a low energy recipient (LE) watershed except during the latter's flood peak period, at which time the ratio of yields is reversed. HE watersheds peak sooner than their corresponding LE watersheds, but also vary more in their peaking date. The ratio of maximum peak flows may be greater or less than 1.0 depending on environmental circumstances.

Hydrograph responses to geomorphic model watershed characteristics and precipitation variables

The primary objective of the Watershed Model Studies Project, reported herein, was to ascertain the effect of selected watershed characteristics on hydrograph parameters under a rainfall simulator. Since most of the runoff contributing to the peak flow was found to emanate from the lower half of the drainage, a measure of watershed eccentricity utilizing easily measured properties in that area is derived and evaluated as a reliable predictor of peak magnitude. In the process of isolating watershed shape, slope, size, drainage pattern, and soil depth were isolated and, along with rainfall intensity, direction of storm movement, and antecedent moisture conditions, evaluated for the models. Studies were made into the similarities between the models and real world watersheds. Three of the several conclusions are 1) the models exhibit hydrologic responses similar to those of a wide range of real watersheds; 2) watershed shape, of itself, does not have a tremendous effect on peak magnitude, and 3) watershed eccentricity is an effective, easily measured, meaningful, and useful expression of watershed shape insofar as that characteristic affects maximum peak flows and certain time parameters of the hydrograph.