HOW MANY RESERVOIRS - AN ANALYSIS OF FLOW RECESSIONS FROM A GLACIER BASIN

Analysis of hydrograph-recession curves from temperate catchments has frequently been directed towards identifying a linear-storage element with mean residence time K which characterizes the delayed-flow component. This paper presents the results of applying such an analysis to recession curves from 11 years of discharge records from a glacier basin. Four reservoirs are identified but their estimated recession coefficients (K values) are found to vary with discharge and with time in the ablation season. This implies that the reservoirs are non-linear. Whilst it may be helpful for the interpretation of glacier-hydrological processes to identify several reservoirs, it appears that a single non-linear reservoir may provide an adequate representation of the glacier for operational forecasting purposes.