Distributed Snowmelt Runoff Analysis for Flood Management in Mountainous Basin of Iran Using Satellite-Based Data (PAP014883)
Soroosh Bordbar, Ali Chavoshian
Flood forecasting and early warning systems
Snowmelt runoff is one of the major causes of flooding in the mountainous basins of Iran especially at the time of an intensive rainfall combined with a relatively warm air mass. Thus, Snow Water Equivalent (SWE) estimation plays a significant role in flood forecasting and developing early warning systems. The goal of this study was to test the possibility of reliable snowmelt runoff and flow forecasting through a simple, fast and conceptual distributed snowmelt model in mountainous basin of Iran with lack of data. SWE estimation models could be categorized into Lumped and Distributed groups. The first group estimates SWE at the outlet of the basin and the second one estimates SWE in a spatially distributed all over basin. While development and application of lumped models for SWE estimation are rather simple and they are widely in use there is a few advantages for distributed models over the lumped ones: SWE estimation is possible in different places of basin, suggesting most critical part of the basin for snow observation stations, proficient management of snow supplies and prevention of natural hazards such as flood. In this study a distributed SWE model has been developed using satellite-based data and Geographic Information System (GIS) to estimate SWE in the mountainous basin of Iran for flood management at various parts of the basin. Using 8-day MODIS snow product (MOD10A2) and daily temperature and precipitation data, SWE has been estimated through the upstream basin of Karun 3 Dam, which is one of the biggest basins in Iran. The distributed SWE has been estimated from 2001 to 2008 by developing a conceptual distributed snowmelt model. Results show that the average runoff volume of the basin in the snow depletion period is 6753 MCM and the R2 is 91%. Additionally, the percentage of snow-melt contribution of each sub-basin is determined. And, appropriate sub-basins for installing new snow observation stations are recommended for the better flood forecasting.