Aquifers are large geological systems spanning multiple territories. Therefore, conflicts surrounding groundwater usage between stakeholders are inevitable. This poses a significant concern since optimal and fair distribution of groundwater remains a challenging problem. In the United States (US), most water conflicts are resolved through litigation. The litigation process is complex, prolonged, and expensive with little guarantee of a just outcome. Recently, Mississippi (MS) sued Tennessee (TN) in the US Supreme Court for groundwater theft. The Court unanimously ruled that interstate aquifers should be subject to the judicial remedy of equitable apportionment. This landmark ruling sets a precedent for future interstate groundwater lawsuits and presents huge implications for groundwater management, as equitable apportionment has never been applied to groundwater. In this research, we analyzed the court documents in the MS v. TN case to identify the issues with the litigation process and present solutions for streamlining it. This research focuses on developing an operational groundwater model for the MS v. TN case study area and establishing methods for using the model to apportion groundwater equitably between the states. A local-scale MODFLOW model will be developed by harnessing public-domain hydrogeological datasets and models, such as MERAS developed by USGS. The new model will be translated into a user-friendly environment, like GMS, for integrating site-specific geological, recharge, and pumping datasets and enabling 3-dimensional representation. As part of this effort, we will emphasize the need to use open-source groundwater modeling tools and data platforms for addressing apportionment problems in future groundwater lawsuits.
.jpg "Frank T.-C Tsai, Ph.D. photo")