Studying Causes of Decreasing Groundwater Level (Case Study: Urmia Aquifer)

Increasing water demand in recent years, industrial and agricultural development and lack of proper management, have led to tensions on water resources, especially groundwater resources. Urmia aquifer is one of aquifers that in recent years faced a severe drop in groundwater level. In this study, with considering of the rainfall, evaporation, temperature, flow of rivers in hydrometry stations and discharge of exploitation wells, contribution of each of factors on the rate of decreasing groundwater level in Urmia aquifer was determined. In order to evaluate changes was used of a hybrid wavelet transform and entropy method. In this study, monthly time series were used for a period of 16 years (2001-2017). Then, the time series was divided to three equal parts and the complexity changes was performed based on the wavelet-entropy criterion (SWS) in these intervals. Results showed that the SWS or wavelet-entropy criterion was reduced in all selected observation wells at all time intervals, which indicates a reduction in the complexity of the groundwater level fluctuations in the Urmia aquifer and as a result of the aquifer's disease. According to the results of this study, the discharge of exploitation and temperature respectively are two parameters main affecting on the decreasing groundwater level in Urmia aquifer