An assessment of snowpack depletion-surface runoff relationships on forested watersheds.

Abstract

A technique was developed for determining daily values of runoff efficiencies from small watersheds by coupling a computer model that simulated Arizona snowmelt processes with graphical techniques of runoff hydrograph separation. The computer program was a USDA Forest Service model modified to better simulate Arizona conditions, A complete explanation of modifications and limitations of the model is given, along with equations for estimating some of the model input variables, Seven small watersheds with a total of 14 years of record were used in evaluating changing patterns of runoff efficiencies within a year. Additionally, many physical, biological, and climatic variables were correlated with seasonal runoff efficiencies not only among years and among watersheds, but also within a watershed among years, and among watersheds within a season, Prediction equations were also formulated that could be of use in the identification of high water yielding watersheds,