Generation of a snow depletion curve for an alpine basin

Snow depletion curves were generated in the 1985 snowmelt season for an alpine basin, the Green Lakes Valley of the Boulder watershed. The assumption, used in several snowmelt runoff models, of homogeneous snow distribution does not apply to the alpine where wind redistributes snow into discontinous patches. The snow depletion curves were implemented into the Precipitation Runoff Modeling System (PRMS) and describe Snow Covered Area (SCA) recession on each Hydrologic Response Unit (HRU) as it relates to the swe/maximum swe ratio. Snow course data were used 1) in curve estimation, 2) to adjust model snowpack in May and 3) to estimate DSCOR, a model parameter that distributes snow in the accumulation phase. Model performance improved substantially after addition of the snow depletion curves especialy in late season due to prolonging of snow contribution to runoff.