Identification of potential groundwater zones in rice-fallow areas within the Mahanadi river basin, India, using GIS and the analytical hierarchy process

To feed the ever-growing population of India, it is essential to bring rice-fallow areas under cultivation, which is mostly restricted owing to surface water scarcity. Groundwater can be a viable alternative to meet the demand which needs to be explored using a suitable mechanism. The present study was undertaken to delineate groundwater potential zones in the rice-fallow areas of Kantamal catchment located in the middle reach of Mahanadi basin (India). These areas can be viable for growing a second crop during the rabi season provided assured irrigation water is available. Groundwater potential zoning is considered as a pre-requisite for groundwater exploration and sustainable well yield. Remote sensing and geographical information system using the analytical hierarchy process (AHP) were used for demarcating groundwater potential zones in the entire catchment as well as in the rice-fallow areas. Thematic layers of lithology, seasonal groundwater storage, lineament density, geomorphology, soil texture, slope, land use/land cover and drainage density were prepared and applied for groundwater potential zoning. The catchment was categorized into very good, good, moderate and poor groundwater potential zones that occupy 23, 24, 42 and 11% area of the catchment, respectively. Rice-fallow area masking over the groundwater potential map reveals that very good, good, moderate and poor groundwater zones are prevalent in 35, 31, 31 and 3% of the total rice-fallow area, respectively. This implies that around 66% of the rice-fallow area in the catchment has a very good to good groundwater potential, which can be judiciously irrigated with groundwater for growing low water requiring rabi crops.