Assessment of groundwater quality for irrigation and drinking using different quality indices and geostatistical methods in Çorum province (Turkey)*

Abstract

Groundwater is widely used for irrigation and drinking purposes. Therefore, assessing groundwater quality is very important for sustainable agricultural irrigation and human welfare. In this study, different water quality indices including electrical conductivity (EC), sodium adsorption ratio, permeability index, sodium percentage, Langelier saturation index, residual sodium carbonate, magnesium ratio (MR), Kelly index (KI), potential salinity (PS), and irrigation water quality index (IWQI) were evaluated to determine the suitability for irrigation. The drinking water quality index (DWQI) was used to assess the suitability for drinking purposes. Spatial distribution maps were created by the ordinary kriging method, using the best semivariogram model parameters for each quality index. The Gaussian model gave the best results for all parameters except for MR and PS. Results from the study area showed that 86.1% of EC, 15.4% of KI, and 52.1% of MR were unsuitable for irrigation purposes, and none of the wells were fit for drip irrigation. The IWQI value was above 70 in 51.2% of this area, which is suitable for irrigation of all plants, whereas it was determined that about 13% of all areas are unsuitable for drinking purposes with regard to DWQI.