Impact of Climate Change on Water Resources of Dokan Dam Watershed

摘要

Lesser Zab is one of the most important tributaries of Tigris River. During the last few decades, the streamflow significantly decreased for long periods followed by extensive flood in short periods. This study aimed to quantify the impact of climate change on streamflow at Dokan Dam until year 2050 using SWAT model based on the scenario of medium emission (A1B) and five climate projection models. SWAT run using Climate Forecasting System Reanalysis (CFSR) was used as weather input data then calibrated and validated on monthly time step for the period from 1980 to 2013 with Nash-Sutcliff Efficiency (NSE) of 0.73 and determination coefficient (R2) 0.73 for calibration processes. The data of this period is more reliable. The result indicated to a significant decrease on the projected streamflow until year 2050 with average streamflow for the six climate models of 167 m3/sec in past compared with the observed streamflow of 176.5 m3/sec for the base period (1980-2013). In addition, the study shows that most runoffs come from Iranian part of the Dokan Dam Watershed with 65% of total simulated runoff. It is highly recommended to improve the efficiency of water using for current and future water projects to meet the expected water shortage.