Assessment of Agricultural Relevance on Groundwater Indicator in a Command Area of Eastern India

Groundwater is a ubiquitous natural resource and one of the most reliable sources of freshwater worldwide. The rapid population growth, water demand in various sectors as well as maximizing agricultural production have led to over-exploitation of groundwater in different parts of the world, including India. Therefore, the information on crop water demands and availability of reliable groundwater resources is necessary for establishing strategies for optimal irrigation water supply. This study aims to map ‘potential groundwater resources’ (PGWR), ‘fraction of vegetation’ (FV) as an alternative crop coefficient using remote sensing data and ‘crop water demands’ and to develop a new indicator named ‘Agricultural Groundwater Resources Indicator’ (AGRI) for ‘Normal’, ‘Dry’ and ‘Wet’ years in the Damodar Canal Command (DCC). The mean, median, SD and CV of the groundwater fluctuation are evaluated at 4.56 m, 4.6 m, 0.85 m and 0.19 m/m, respectively. The maximum and minimum potential groundwater resources were computed at 1247 mm and 245 mm, respectively. The maximum annual crop evapotranspiration (ETc) for the ‘Normal’, ‘Dry’ and ‘Wet’ years of the study command was computed at 1166 mm year−1, 1290 mm year−1 and 999 mm year−1, respectively. During the ‘Normal’ year, crop water demands in about 60% of the study area could be fulfilled from the PGWR supply. In this study, an indicator named AGRI was used for the first time in identifying possible spatial irrigation adequacy from the potential groundwater resources. The map of AGRI could be the reference map for managing the uniform distribution of irrigation water supply in the DCC. The developed AGRI map will provide valuable information to the water planners, water managers, decision-makers, engineers, agriculturists and farmers in particular for sustainable water management. Being adaptive in nature, the proposed model can be applied worldwide irrespective of diverse agro-climatic conditions.