Standard Parameter Values for Long-and Short-Term Runoff Model

Abstract

We propose a set of standard parameter values for the Long-and Short-Term Runoff Model (LST model) based on calibration in eight mountainous basins, varying in area from 21.2 to 1, 717km².
In order to see the difference between the proposed standard LST model and thecalibrated eight LST models, a numerical experiment was made. In the experiment, continuous simulation of flood and long-term runoff using 14 years data including 18 floods was carried out. It is shown that calculated peak discharges of the 18 floods by the standard LST model are practically equal to or slightly greater than the averages of peak discharges by the calibrated eight LST models. Also, flow duration curves by the standard LST model are almost equal to the averages.
Next, the 14 years data were used to compare the standard LST model with the standard tank model which Sugawara (1979, 1984) recommends. The calculated daily runoff in both cases are found to be quite close.
Moreover, for the purpose of applicability, we applied the standard LST model to daily runoff in three other mountainous basins, and found calculated daily runoff to be in good agreement with the observed runoff. The proposed standard parameter values of the LST model is expected to be useful for estimation of river flow in ungauged watersheds.