Use of areal snow cover measurements to develop snowmelt-runoff relationships for Arizona

Abstract

In the Rocky Mountains, most streamflow results from snowmelt and the demand for water in the western United States makes the value of accurate streamflow forecasting high. Studies have shown that snowpack depletion-runoff relationships have the potential to improve various streamflow forecasting techniques. However, the use of these relationships in streamflow forecasting has been limited by the difficulty in obtaining measures of areal snow cover. The Earth Resources Technology Satellites (ERTS) have shown potential for measuring areal snow cover. Therefore, a study was conducted to determine the feasibility of using ERTS imagery to measure changes in snow cover in east-central Arizona for use in developing snowpack depletion-runoff relationships. Results indicated that, despite some difficulties, ERTS-l imagery could be interpreted for areal snow cover. Also, a highly significant relationship existed between measures o£ areal snow cover from ERTS-l imagery and subsequent runoff during the snowpack depletion period. However, quality ERTS-l imagery cannot presently be obtained frequently enough to be the sole source of data for monitoring changes in areal snow in Arizona. In addition, a delay in obtaining ERTS imagery must be overcome before the data from ERTS imagery can be used for practical applications.