The zoning of drinking water resource quality by combining Analytic Hierarchy Process and GIS in the north of Qazvin Plain

Identifying acceptable drinking water sources depend on the methods which always incorporate the correct and logical choices. One of these methods is combination of Analytical Hierarchy Process (AHP) and Geographic Information System (GIS), which is one of the appropriate assessment tools for groundwater management. The main objective of this study is to evaluate groundwater quality for drinking purposes in Qazvin plain. In order to build the groundwater quality map of this area, water quality parameters of 17 wells including total dissolved solids, hardness, sodium, chloride and sulfate during 2013 was measured. At the first step, the zoning map parameters were drawn by Interpolation method, Inverse Distance Weighted (IDW), then classifications of maps were prepared based on Schoeller method. Afterwards the weights of the parameters were determined with the help of AHP. In the final stage, groundwater quality map of the study area was created by multiplying their combined weights to related zones. The results showed that about 83 percent of the area water quality is good and acceptable and about 17 percent is inappropriate. It could be concluded that most of the water in the study area in the Qazvin plain has good quality while central and eastern parts have more drinkable water sources.