A stock pond simulation model for chaparral watersheds in Arizona

Abstract

A previously developed methodology to model the hydrologic performance of stock ponds is modified and tested using data from Arizona chaparral watersheds. The modified method uses stochastic computer models to generate time series' of daily precipitation and temperatures, then transforms this synthetic data into daily streamflow using a soil moisture accounting model. The streamflow model, called a Generalized Streamflow Simulation System, is used to simulate the long "baseflow" recessions typical of chaparral watersheds. Generated streamflow is routed through a set of standard stock ponds to yield statistics and probability distributions for the following annual pond performance criteria: runoff retention, spillage, and pond dry days. A case study of pond performance on a chaparral watershed is performed using the calibrated simulation model. Simulation results are discussed in the context of previous case studies for other areas of Arizona. Simulation results, computer program listings, and sample outputs are included in the report.