Assessing climate change impacts on groundwater fluctuation in Borkhar Plain, Isfahan

Nowadays, global climate change has been observed which had an impact on both surface and groundwater resources management. The main objective of this research is change detection of groundwater fluctuation caused by climate change in Borkhar Plain, Isfahan Province. In this way, both Mann-Kendal and Sen’s slope non-parametric analysis were used using 19 piezometric wells data for the period of 1991-2019. Pearson correlation matrix along with correlation between climatic elements including temperature, precipitation and evapotranspiration (Thornwhite) with water table levels were determined. Based on this, a multivariate regression model was developed to model the annual time series at a confidence level of 0.95. Climatic factors of 2080-2099 period were simulated using the output of HadCM3 model through Lars-WG downscaling model for Maymeh Station under two scenarios A2 and A1B and based on the developed regression model, the water level of Borkhar Plain was simulated. The results showed that in the base period, the water table in the study area has been decreased with an annual slope of 47 cm per year. Correlation analysis showed that the three climatic elements of precipitation, temperature and evapotranspiration in a linear composition modeled 0.75 of the annual groundwater changes in the plain. The results of the exponential microscale model implemented on HadCM3 data showed that in the period 2080-2099 under both scenarios, the groundwater level of the region will decrease between 15 to 17 meters compared to the base period.