A basinwide stochastic model for ephemeral stream runoff in south-eastern arizona

Abstract

A stochastic model for generation of synthetic data on basins of 100 mi2 or less is developed using data from the Walnut Gulch Experimental Watershed in south-eastern Arizona. Variables describing the intermittent and independent runoff events are: start of runoff season, number of runoff events per season, time interval between events, beginning time of runoff event, volume of runoff and peak discharge. Each of these variables is generated from its own probability distribution. The means and standard deviations of the various distributions form the set of parameters that define the stochastic model. Some parameters are expressed as functions of drainage area and some are assumed constant for the range of basin areas used in the study. The means of the runoff variables vary with basin area while the standard deviations appear to be independent of basin area. By describing the variation of the model parameters with basin area, a model for a specific basin is developed into a model of a general basin for runoff events. © 1972 Taylor & Francis Group, LLC.