Determination of groundwater quality based on important irrigation indices using analytical hierarchy process method

The purpose of this research is the zoning of groundwater quality for agriculture usages in the Eyvanakey plain, conjugating Interpolation methods by Geographic Information System (GIS) and selection of the best weights in Analytical Hierarchy Process (AHP). Achieving this aim, groundwater quality data from 19 wells in Eyvanakey plain were used. First, raster maps of the study area was prepared, using Inverse Distance Weighted (IDW) method, containing the Sodium Absorption Ratio (SAR), Permeability Index (PI), Kelley Ratio (KR), Magnesium Absorption Ratio (MAR), Residual Sodium Carbonate (RSC), Sodium solubility Percentage (SSP), Electrical Conductivity (EC) and Total Hardness (TH). Then, the final weights of parameters were determined by Hierarchical Analysis Process and pairwise matrix. Finally, the map of groundwater qualitative potential for agricultural purposes, prepared, using map overlaying and final weights of the parameters, applying in GIS. Results showed, the groundwater quality for agriculture uses in center and south is bad whereas at east is moderate and at west it was good.