The Zoning of Groundwater Quality and Quantity for Agricultural Purpose using Wilcox Model and Geographic Information System (GIS): A Case Study

Changes in groundwater quality and quantity usually occur as a results of mismanagement, is introduction of the other resources destruction either directly or indirectly. Given the importance of agriculture in Mehran plain, the aim of this study is to investigate the changes in quantity and chemical quality of groundwater from 1996 to 2013. In order to study the quality of underground water three variables including EC, SAR and CL and to evaluate the quantitative changes water height were used. Then, zonation maps were prepared using ArcGIS9.3 software. The Wilcox diagram was used to assess the water quality of agricultural area. According to the results of Wilcox classification the water quality was suitable for agricultural irrigation in much of the area. The results of ground water quality showed the parameters of chlorine and sodium adsorption ratio of the area have a good quality but the electrical conductivity is poor. It has reached even more than 2650 μm/cm in parts of the region. Water table decrease has occurred most sharply in 2013 reducing the water level. The electrical conductivity, sodium adsorption ratio, chlorine and water level decrease have increased from the southern and eastern part on the study area to the West and North West. These can be related to the recently droughts and an over utilization from wells in the study area.