Investigating the Effects of Climate Change on Groundwater (Case Study: Sarab Plain)

Climate change phenomenon has caused considerable changes in surface water and groundwater resources during the recent years. Groundwater is one of the important resources of the fresh water in every region and it is very important to investigate the effect of climate change on it.  In this study, the effect of climate change on water table changes in Sarab plain aquifer in the future time period of 2021-2050 was investigated using Atmosphere-Ocean General Circulation Model(AOGCM). For this means, the climate change data resulted from 16 models of AOGCM-AR4 under the emission senarios of A2 and B1 during two time periods of 1986-2015 and 2021-2050 wereweighted for the studied area.  Based on the weights of the climatic models and the amounts forecasted data by them for the future time period, the variations of the precipitation and air temperature were calculated with the probabilities of 10, 50 and 90 percent. The statistical model of LARS-WG was used todownscale the amounts of precipitation and temperature for the future time period. Using the precipitation-runoff models of NARX and MODFLOW the daily magnitudes of the runoff and water table fluctuations were estimated too. According to the results, water table will be declined about 0.0 to 10 meters comparing to the year 2001 in most of the aquifer areas under both scenarios. This decreasing trend is more visible under the scenario B1 comparing to the scenario A2.