Evaluating Quantitative and Qualitative Changes in the Aquifer of Abu-Ghoveyr Plain using geographical information system

Harvesting and recognition of water quantity and quality is an essential step to optimization of consumption. Water quality is affected by environmental conditions and human activities.The main objective of this study is to evaluate the quantitative and qualitative changes in the Abu-Ghoveyr aquifer in Ilam Province in a 14- year period from 2001 to 2014. To this end, the statistics for 33 quantitative and 10 qualitative wells were used, after analyzing the data using ArcGIS software, iso_potential and iso-decline maps were developed. Moreover, the unit groundwater hydrograph was obtained for the region. In order to evaluate the quality of the groundwater, Electrical conductivity (EC) and chlorine (Cl) were Sampled and analyzed. The results obtained from iso-decline maps show that the different sections of the plains have had a decline between 1 to 10 meters during the selected period. During this period, the water level had an average decline of 2.65 meters (annually 20 cm). In order to determine the effects of rainFall on the levels of groundwater, the precipitation of this period was also considered. The results revealed that the highest level of water in the year 2004 was 77 m and the greatest amount of precipitation was 350 mm during that year.The results indicate the presence of a significant relationship between rainFall and the water levels. Investigating the parameters of EC and Cl level indicate the increase of these parameters in this period. Moreover, the central regions of the plains have a lower quality compared to other sections which is due to the concentration of wells and higher decline of water level in this area. Hence, it can be concluded that the most important factors in reducing the underground water levels and lowering the quality of Abu Ghoveyr Plain include drought, over exploitations, and the excessive number of wells.