Integrated GIS-based modelling approach for irrigation water quality suitability zonation in parts of Satluj River Basin, Bist Doab region, North India

Abstract

The groundwater is the main source for irrigation and other purposes in the alluvial plains of Punjab. The poor irrigational water quality affects the soil quality which interrupts the growth of plants impacting the agricultural production and can cause risk to human health, and thus, it is important to evaluate the water quality for irrigation uses in the agrarian regions. An integrated GIS-based modelling approach along with conventional water quality indices such as sodium adsorption ratio, per cent sodium, residual sodium carbonate, residual sodium bicarbonate, magnesium hazard, permeability index, potential salinity, Kelly’s ratio, electrical conductivity, total hardness, pH and total dissolved solids was used to delineate the irrigation water quality suitability zones in parts of agricultural prolific Satluj River Basin. Analytical results revealed that groundwater of the study area is very hard and slightly alkaline in nature and the relative abundance order of major ions is Mg2+ > Na+ + K+ > Ca2+ and HCO3− + CO32− > Cl− > SO42−, respectively, for cations and anions. The weighted overlay technique was applied to generate the irrigation water quality zonation map, and results revealed that nearly 3.2% (117 sq. km) of the total area was not suitable for the irrigation water quality, whereas 85.2% (3076 sq. km) and 11.6% (421 sq. km) area fall under moderately suitable and suitable classes, respectively. The elevated level of some ions found in the shallower zone as compared to the deeper zones indicates that in addition to the geogenic factors (weathering and dissolution of aquifer materials) anthropogenic inputs such as ill agricultural practices, leaching from septic tanks and municipal waste are adversely affecting the groundwater system in the region. The results of US Salinity Laboratory’s diagram showed that 42% groundwater samples fall in C3S1 (high salinity with low sodium hazard) category indicating the unsuitability for irrigation purpose due to high salinity hazard and cannot be used in soils with restricted drainage. The results of Piper and Durov diagrams revealed that Ca2+–Mg2+–HCO3− is the dominant hydrochemical facies with Mg2+–HCO3− water type in the groundwater of the study area and hydrochemistry is controlled by both natural and anthropogenic factors. The bottom-up approach and involvement of locals can boost the management of water resources in the study area.