جغرافیا و پایداری محیط (Nov 2013)
Analysis of the Effect of Precipitation Type on Flow Simulation in Talar and Khoramabad Watershed
Abstract
Using a model with integrity and high performance to simulate the hydrological process in deferent watersheds is very important. Present study aims to assess the efficiency of SWAT model in simulating the produced runoff of different precipitation in Khorramabad watershed with 2467 square kilometers and in Talar watershed with 2057 square kilometers. Average precipitation in Khorramabad and Talar watershed is 560 mm and 612 mm respectively. Besides, both of them have semi-hummed climate. Therefore, the maps of land use, soil, digital elevation model and meteorological data were collected for each region. Hydrological response units (HRU) was determined in 223 in Talar and 265 HRU khorramabad watershed by overlapping spatial layers. The SUFI2 algorithm was used to analyze parameter sensitivity and determine optimal values for parameters. The results showed that curve number parameters have high sensitivity in both watersheds. NS and R2 statistical coefficients were used to determine optimal values of model efficiency. The values of these coefficients in Khorramabad watershed are 0.74 and 0.72 respectively and in Talar Watershed are 0.64 and 0.66 respectively. The results showed that the types of precipitation have pivotal effect on model output and occurring snow precipitation decreases performance of the model. Overall, the results showed that the SWAT model availability is appropriate enough in both watershed and this model can be used for watershed management in these areas.
