Future water allocation and in-stream values in the Willamette River Basin: A basin-wide analysis

Our research investigated the impact on surface water resources of three different scenarios for the future development of the Willamette River Basin in Oregon (USA). Water rights in the basin, and in the western United States in general, are based on a system of law that binds together all water rights in a basin in a potentially complex web of interactions. We therefore analyzed the scenarios using a basin-wide approach, in which we simulated the allocation of surface water across all water rights in the entire basin. Our analysis focused on two particular issues: the impact of increased urban demand for water; and protecting ecological values through an existing program to conserve water and devote the savings to in-stream water rights. The latter represented what key stakeholders in the basin felt was the greatest environmental protection that was politically feasible. The results of our simulations were inconsistent with all of our expectations. We found that the web of interactions was not extensive, and that a basin-wide approach wasn't warranted. Increased urban demands had little impact on water allocation, but even an extensive application of the existing water conservation program was not sufficient to protect ecological values. As a result, we believe that protecting ecological values in the future will require sacrifices from more than water rights themselves, and involving society as a whole, in terms of not only the resources devoted to protecting the environment, but also the political will to make difficult changes.