Cumulative snowmelt runoff distribution graphs and their use in runoff forescasting

Procedures for refining total seasonal runoff forecasts as the snowmelt season progresses are presented on the basis of temperature and runoff data. Methods described were developed for operation in the Seminoe Reservoir in the North Platte River Basin, Wyoming. The principle of snowmelt runoff variations with changes in temperature is used to develop mass curves of accumulated values of day-degrees of melting temperatures against accumulated daily inflow to the reservoir. The mass curves have a striking similarity in shape. The possibility of comparing accumulated runoff expressed in percent of total seasonal runoff with accumulative day-degrees of melting temperature are investigated. Cumulative snowmelt runoff distribution graphs are developed. A definite relationship is found to exist between the percent of seasonal snow melt and cumulative temperatures.Discussion by Walter U. Garstka and Milton S. Sachs.