Groundwater quality assessment for irrigation suitabilityin salinity affected coastal river basin of Gujrat

Abstract

The groundwater system along the coast of Saurashtra is affected by high salinity. In the Minsar river basin, the groundwater salinity varies from very high near the sea coast to medium and low salinity values in the upland areas. Chemical analyses of water samples in the region show that calcium and magnesium are the dominant cations present in groundwater next to sodium. Similarly, bicarbonate anion is also present in considerable amounts next to chloride. To assess the suitability of groundwater for irrigation purposes, a total of 71 groundwater samples, collected from zones at varying distances from the sea coast, were analyzed for computing water quality indicators viz., salinity, sodium absorption ratio (SAR), percent sodium (%Na), residual sodium carbonate (RSC), magnesium hazard (MH), permeability index (PI) and boron concentrations. US Salinity Laboratory based classification was also carried out. Results reveal that quality of groundwater for irrigation is more suitable at distances generally beyond 12 km from the sea coast. Proper soil management and selection of crops with good salt tolerance are recommended in the region.