Hydrochemical assessment of groundwater suitability for irrigation in the north-eastern blocks of Purulia district, India using GIS and AHP techniques

Purulia is a semi-arid, hard rock terrain. Water scarcity is a major threat prevailing here, but irrigation is been performed in many parts of the district mostly by the use of the surface and groundwater. Proper water management planning is very much essential in the region so that water can be utilised in the best way possible without causing much exploitation and waste. The various physicochemical parameters were measured in the field and in the laboratory for the collected 60 samples. The decreasing order of occurrences of the cations and anions in the groundwater of the study area are as; Ca+2 > Na+ > Mg+2 > K+ > Fe+2 and HCO3- > Cl- > SO4- > NO3- > F- respectively. According to the piper plot the water type are 80% Ca-HCO3, 19% mixed CaMgCl and 1% CaCl type. Gibbs diagram indicates that the rock-water interaction is the most dominating mechanism prevailing in this region. The groundwater suitability zones for irrigation purpose were performed using the analytic hierarchy process (AHP) and geographical information system (GIS). The final zonation map was prepared using the weighted analysis technique by using the nine irrigational water parameters. The zonation map indicated that 32.37% and 19.23% of the study area are highly and low suitability zones respectively. The results from this study would help the decision makers in the coming future for making water and irrigation management programs.