Magnitude and modelling of snowmelt runoff in the Cairngorm mountains, Scotland

Abstract

Streamflow in the River Feshie (106 km²) shows persistent diurnal oscillations from March to June when runoff augmented by snowmelt greatly exceeds precipitation. Diurnal amplitude and maximum daily runoff are comparable to a similar-sized Swiss glacier basin. Daily discharges in the springs of 1979 and 1980 are successfully simulated from daily air temperatures and precipitation using a lumped degree-day model based on Martinec's model but with endogenous snowpack shrinkage at a rate proportional to melting. A best fit of R² = 0.88 was achieved over 53 days in the unusually snowy season of 1979. The biggest errors are in simulating runoff from precipitation for which only lumped data are available. Best-fit parameter values are physically reasonable and only two parameters, describing the initial snowpack, need vary from year to year.