water, compact, sovereignty, equitable apportionment, Commerce Clause


Water managers have long called for management at watershed scales, instead of using hydrologically arbitrary boundaries like political borders. Considerable effort has been made in recent years to manage watersheds more holistically, but efforts to transfer water across state boundaries have been problematic, thwarted by legal and political obstacles. In Tarrant Regional Water District v. Herrmann the transferability of water across state boundaries has been reviewed by the Supreme Court. Tarrant, a water district in Texas, attempted to reallocate water from Oklahoma. The U.S. Supreme Court interpreted the case narrowly, focusing on the wording of the Compact, and determined Congress and the signatory states allocated water between each state. While the end result was a setback for Tarrant, many questions remain about the overall reallocation of water across state lines. An increasing node within natural resource economics literature finds boundary-less water markets an equitable way to reallocate water in scarcity prone areas like the American West. Over twenty large river basins in the western United States are governed by interstate compacts. With water demand likely to intensify because of increasing populations and the impacts of climate change, understanding the transferability of these waters is imperative for water managers and city planners.