Analysis of the Applicable Algorithm for Estimating Rrunoff from Snowmelt Using Hydrological Models (SRM) and Techniques of Remote Sensing

The overall objective of this study was to estimate the impact of runoff from snowmelt on Samoush River discharge. Samoush River is located in Galan Province in northern Iran. The size of the watershed is about 100 km² and it receives about 150 centimeter of snow annually. The findings from the study will be used to predict maximum probable flood and 1% chance flood (base flood or 100-year flood) to plan for flood mitigation in downstream towns and villages. A flood forecasting and flood warning system is needed for the area to protect the residential areas adjacent to the river and streams within the watershed of Samoush River. The preliminary findings from the study shows that the use of satellite or similar MODIS (moderate-resolution imaging spector-radiometer) images, can be very useful for spatial and temporal monitoring of snow cover and snow surface temperature in mountainous areas. The use of the research products from this study along with weather forecasts that provide inputs into hydrological modeling is very important in the development of a flood warning system in this region. Hydrological modeling of rainfall-runoff in this basin using the SRM (snowmelt runoff modelling) modeling package and satellite data delineating snow cover and temperature time series suggests that snowmelt provides a large proportion of runoff and discharge in the Samoush River. For example, in the water year 2002-2003 the share of runoff from rainfall and snow melt were almost equal. In rare events sudden temperature rise can cause catastrophic flooding due to the quick snow melt during non-rainy weather.