Snowmelt at an Index Plot

A small experimental index plot has been installed in the open at a climatological station in the North Nashwaaksis Stream Basin, N. B., to obtain a reliable regional relation between snowmelt measured at the plot and meteorological parameters thermodynamically related to the snowmelt process. The data collected during the 1966 spring snowmelt season were analyzed by three methods: The degree‐day method, the U.S. Corps of Engineers generalized snowmelt equations, and optimal regression equations derived from the measured snowmelt at the index plot and related thermal budget indices formed from individual meteorological parameters or a rational form of their product combinations. All three methods gave generally comparable results; their specific merits and limitations are discussed in the text. The per cent deviation of seasonal totals by the three methods varied from −15.6 to +54.5%. A comparison of the relative accuracy of the three techniques as daily predictors was obtained by taking the root‐mean‐squared values of the deviations of daily estimated snowmelt from the daily measured values; these ranged from 0.17 to 0.22 in. It is suggested that experimental index snowmelt plots and computerized optimal regression equations offer possibilities for dependable predictions of point snowmelt rates that may be used as input information for estimation of basin‐wide snowmelt and hydrograph synthesis.