SNOW AND GLACIER CONTRIBUTION FROM ITALIAN ALPS FOR SEASONAL RIVER DISCHARGE IN TAGLIAMENTO RIVER

Abstract

This study estimated the contribution of seasonal glacier and snow cover variation on runoff generation in the Tagliamento River catchment in Italy. The normalized difference snow index (NDSI) and band combination method were employed to estimate the glacier and snow melting over different seasons in two catchments and link with the tank model to simulate the river discharge. Approximately 51 percent of the catchment area is covered with glacier and snow during the winter, which dramatically reduces to about 5 percent during summer. Markedly, 50-75 percent of the river discharge from April to June is generated by the glacier and snow melting. With reference to the climate change, it is noted that the snowpack in this region is often close to its melting point (e.g., -0.9°C in February), which may respond rapidly even to minor changes in temperature (62 km²/°C) resulting possible early season runoff. The dependency of the model parameters on different climatic and geographical settings was also discussed.