Storage volume and exploitation changes of aquifers in the eastern plains of Kurdistan province

In the past, exploitation from aquifers was limited due to lack of modern technology. During past three decades, the methods of aquifer discharge have changed gradually so that using modern exploitation systems such as deep and semi-deep wells is very common. Using these kinds of wells, water discharge from aquifers has dramatically increased and the charging level has not been into account and, as a result, the groundwater level has been decreasing. In this study, the exploitation status, the storage volume changes as well as the changes of the storage volume of forbidden aquifers such as Qorveh, Dehgolan and Chahardoli were analyzed during 2017-2018 water year. Accordingly, Saturation thickness, with the same depth level and direction maps of groundwater flow in the aquifers were prepared using ArcGIS and then the effects level of each well was calculated through polygon Thiessen. Pysometric heights of the aquifers for different years were calculated by weighted average and unit hydrograph diagrams were drawn for each. Analyzing unit hydrograph diagrams of eastern plains of the province during a 31-year period (1987-2018) indicated that the ground water level has a decreasing trend. The calculation of ground water balance of the aquifers indicated that the cumulative deficits for Qorveh, Dehgolan and Chahardoli aquifers were 2, 17.4 and 2.98 MCM respectively, so the balance is negative. Generally, although exploitation is forbidden in eastern plains in Kurdistan and too much efforts should be done specifically by farmers, the storage has encountered cumulative deficit by 22.2 mcm.