Capability of Mehran plain's groundwater for irrigation of agriculture lands in GIS environment

Mehran plain، having about 300 km2 area، is one of the widest plains of Ilam Province. Because of extensive agriculture lands، numerous shallow and deep wells are drilled in the plain، therefore، study of the groundwater as the main water resource of the area is very important. In order to study the groundwater، at first quantitative and qualitative data of wells and piezometers was collected and by inspecting the physical condition of the aquifer، the maps of potential، depth and flow direction were prepared. Based on information layer of wells، the electrical conductivity (EC) map of the area was prepared to get information about the water quality for agriculture uses. Finally، groundwater was classified for agriculture uses based on Wilcox diagram. Then، using the diagram and also EC map and sodium adsorption ratio (SAR)، the capability of groundwater for irrigation was prepared in the geographical information system (GIS). Results showed that the quality of groundwater for agriculture uses is suitable in most parts of the plain and only a small area in the western area of the plain is unsuitable.