Evaluation of water demand and supply under varying meteorological conditions in Eastern India and mitigation strategies for sustainable agricultural production

Abstract

Spatio-temporal variability of water demand and supplies under different meteorological conditions and their linkage with dynamic groundwater (annually utilizable groundwater) reserve was investigated in a Canal Command (area irrigated by a canal system) of Eastern India. Annual irrigation water supply from surface water sources (i.e., canal, river lift and tanks) and groundwater sources (i.e., shallow and deep tubewells) was estimated for different meteorological conditions. Annual water demands as crop irrigation requirements (CIRs) for the prevailing cropping patterns in the study area were also assessed under different meteorological conditions using crop evapotranspiration and effective rainfall data. Thereafter, the estimated irrigation water supply and irrigation water demand were subjected to spatio-temporal and statistical analyses. The mean annual CIR in the study area was estimated at 7002 ± 852 MCM during 2004–2013 period. Boro paddy was found to be the most water-consuming crop, accounting for about 50% of the total crop water requirements. The mean annual dynamic groundwater reserve (DGWR) in the study area was estimated to be 5169 ± 782 MCM. Considering DGWR as an additional source of irrigation water, 28, 25 and 35 blocks were characterized as ‘water surplus’ during ‘normal,’ ‘dry’ and ‘wet’ years, respectively. Also, DGWR substantially reduced demand–supply gaps in the remaining blocks. The surplus water available in the blocks due to DGWR availability could be used to mitigate water-deficit condition in neighboring blocks. Thus, this study suggests cost-effective alternatives for the efficient management of available water resources and identifies management strategies for sustainable agricultural production under diverse climatic conditions.