Interstate Groundwater Law in the Snake Valley: Equitable Apportionment and a New Model for Transboundary Aquifer Management

As demand for freshwater increases and surface water supplies diminish, states are increasingly tapping groundwater to meet their water needs. Like rivers and lakes, groundwater aquifers cross state lines and create legal challenges for allocation and management. For over a century, the Supreme Court has applied its equitable apportionment doctrine to allocate shared surface water supplies between states. The Court has not yet been faced with an equitable apportionment action for groundwater, but several disputes are emerging around the country that may soon command the Court’s attention.This article examines how the equitable apportionment doctrine can be applied to an interstate groundwater dispute, using the Snake Valley Aquifer shared by Nevada and Utah as a case study. Equitable apportionment is a viable doctrine for resolving interstate groundwater disputes, but it is not ideal. Instead, interstate compacts provide a Constitutional mechanism for cooperation by which states may protect and utilize a shared natural resource. There are over twenty interstate compacts currently in effect, covering major interstate waters such as the Colorado River and Great Lakes. Some of these compacts address connected groundwater, but none to date are focused on sustainable aquifer management. Recently, Nevada and Utah have developed a proposed agreement to manage the Snake Valley Aquifer. While the proposed agreement was rejected for political reasons, and the Snake Valley Aquifer dispute itself seems headed for litigation, the agreement provides a model for sustainable and cooperative transboundary aquifer management.