Evaluation of water quality for irrigation purposes in Urmia alluvial plain (Iran)

The aim of this study is to evaluate suitability of groundwater for irrigation purposes in Urmia alluvial plain, West Azerbaijan, Iran; where agriculture activities are dependent on groundwater because of increasing drought trend in Lake Urmia. Fifty-nine water samples from groundwater were selected during dry season in 2018 and analyzed for water quality parameters. The present study was carried out to investigate the spatial variability of water quality indices (PI, MAR, SAR, RSC, LSI, KR and %Na) by geo-statistical methods to determine suitable areas for irrigation. Electrical conductivity (EC), pH, calcium, sodium, chloride, sulfate, potassium and TDS concentrations were in permissible limit, while %8.5 and %17 of groundwater wells; in bicarbonate and magnesium, respectively; were higher than acceptable limit within prescribed limits as FAO (1994) for irrigation purpose. The calculated SAR values suggested excellent quality for irrigation. The values of PI and %Na suggest that the groundwater of study area is suitable for irrigation purpose. It shows that concentrations of MAR in %18.6 of wells and RSC values in three of samples, are lower than the permissible limit; Whereas computed values of LSI and KR indicate unsuitable groundwater of study area. The spatial distribution maps of groundwater quality indicated that the central of Urmia plain is the most suitable zone for irrigation purposes.