Impact assessment of climate change on environmental flows by using hydrological indicators Case study: Kordan River

Our country is located in a geographical position where exposure to climate changes effects. Therefore it is necessary to assess its influence on water resources. Because this part of ecosystem is the first section that will be unaffected by climate change. The main purpose of this study is assessment of climate change impacts on environmental flows by using hydrological indicators in Krdan River. In this regard, at first, the future climate change in the region was projected by using HadCM3 general circulation model in three 30-year periods 2011-2040, 2041-2070 and 2071-2099 considering A2 and B1 scenarios. Afterward, Kordan streamflow was simulated by SWAT model for baseline period (1985-2010) and future. Finally, indicators of the hydrologic regime including magnitude, duration, timing, and frequency of extreme flows were analyzed. Following, IHA(Indicators of Hydrologic Alteration) Results showed a reduction for discharge. Under A2 scenario, discharge decreased from 3.31 (m3/sec) to 2.66 (m3/sec). Under B1 scenario the reduction was up to 2.86 (m3/sec) for 100 years later. In addition to reduction of discharge, the occurrence time of maximum and minimum flows will change, too. This phenomenon will change the habitat suitability and make some risks for aquatics life.