Modelling the Reallocation of Groundwater in the context of its usage in Agriculture

Abstract

In the state of Maharashtra, post-monsoon crops are mainly dependent on groundwater. The groundwater availability at every farm is different, even though farms get the same recharge from the rainfall. This happens as the groundwater flows along the water table gradient. Hence understanding and estimating the groundwater reallocation is important for irrigation. In this project, the cropping and irrigation practices adopted by the farmers in the post-monsoon seasons (Rabi or winter season and summer season) were understood from the farmers’ narratives. The hydrology of groundwater flows was studied. A computational model that could simulate the reallocation of groundwater is made. The model uses elevation, cropping pattern and initial well levels as primary input data and storativity, hydraulic conductivity, aquifer depth, and irrigation requirement of each crop as secondary input data. The results of the GWR model were verified against one of the standard groundwater modelling software. The model is not data and computation heavy and hence easily expandable in terms of area to be simulated and number of timesteps. The primary inputs required are easily measurable at the village level making it user friendly. The model can be used as a tool for decision making at an individual as well as collective level as it can predict the availability of water. The reallocation results are useful for policy-making and administrative decisions.