Irrigation and municipal water quality zoning by GIS

Water quality determining in water resources evaluation is significantly important and its monitoring and zoning are key factors which should be considered in town planning. The aim of this study is identifying the most appropriate interpolation method for water quality determining by using Schuler and Will Cox diagrams in drink and agriculture sectors. Over this study, 22 piezometric wells are used in an unconfined aquifer located in Malayer plain. To determine the quality of drink and agriculture water, Schuler and Will Cox diagrams that are the most common classification methods are used respectively. Geostatistical methods that namely Kriging, Co-kriging and Inverse Distance Weighing (IDW) are used in GIS for water quality zoning in the study area and their results are compared to each other as well. The results showed that the simple Co-kriging technique (spherical) is the most appropriate interpolator for interpolating and zoning the drink and agriculture water quality. Investigation of drink water quality based on Schuler diagrams with considering TDS and TH parameters showed that the drink water quality is divided into three groups; good, acceptable and inappropriate. In the agriculture sector based on Will Cox diagrams using EC and SAR parameters, agriculture water quality is measured into two groups; good and average.