The flow regime of Himalayan rivers is dominated by monsoonal rainfall and melt water from snow and glacier during the non-monsoon months. Satluj is a major tributary of the Indus river system in western Himalaya. The rivers’ watersheds experience extensive snowfall during winter and snow/glacier melt runoff substantially contributes to the streamflow in the spring and summer months. In the upper part of the Himalayan catchments, major source of inflow is from snow/glacier melt runoff. In order to understand the hydrologic response of the headwaters of Satluj river up to Rampur, hydrological modeling is carried out using the semi distributed hydrological model Soil and Water Assessment Tool (SWAT). The Sequential Uncertainty Fitting algorithm is used to calibrate and validate the model against observed daily streamflow and incorporate uncertainties in the analysis.
The model has been used to evaluate the water balance in the catchment and quantify the contribution of snow/glacier melt runoff at the outlets which is having significance in the light of climate change also. From the results, it is found that the average contribution of snow and glacier melt runoff in the Satluj river at Rampur is about 68–71% of the annual water yield of about 600 mm. The actual evapotranspiration for the basin comes out to be 13% of the total precipitation. The water yield for the basin is about 58–62% of the precipitation. The major part of the total runoff is obtained during early summer period, however glacier melt contributes during later monsoon period. The contribution of snow/glacier melt runoff was found to be quite reasonable as compared to the earlier studies.
Flow, Satluj, Snowmelt, Water balance, Himalayan
