Conjunctive surface and groundwater management in Utah: Implications for oil shale and oil sands development

Unconventional fuel development will require scarce water resources. In an environment characterized by scarcity, and where most water resources are fully allocated, prospective development will require minimizing water use and seeking to use water resources in the most efficient manner. Conjunctive use of surface and groundwater provides just such an opportunity. Conjunctive use includes two main practices: First, integrating surface water diversions and groundwater withdrawals to maximize efficiency and minimize impacts on other resource users and ecological processes. Second, conjunctive use includes capturing surplus or unused surface water and injecting or infiltrating that water into groundwater aquifers in order to increase recharge rates. Conjunctive management holds promise as a means of addressing some of the West's most intractable problems. Conjunctive management can firm up water supplies by more effectively capturing spring runoff and surplus water, and by integrating its use with groundwater withdrawals; surface and groundwater use can be further integrated with managed aquifer recharge projects. Such integration can maximize water storage and availability, while simultaneously minimizing evaporative loss, reservoir sedimentation, and surface use impacts. Any of these impacts, if left unresolved, could derail commercial-scale unconventional fuel development. Unconventional fuel developers could therefore benefit from incorporating conjunctive use into their development plans. Despite its advantages, conjunctive use is not a panacea. Conjunctive use means using resources in harmony to maximize and stabilize long-term supplies - it does not mean maximizing the use of two separate but interrelated resources for unsustainable short-term gains - and it cannot resolve all problems or provide water where no unappropriated water exists. Moreover, conjunctive use may pose risks to ecological values forgone when water that would otherwise remain in a stream is diverted for aquifer recharge or other uses. To better understand the rapidly evolving field of conjunctive use, this Topical Report begins with a discussion of Utah water law, with an emphasis on conjunctive use issues. We contrast Utah's approach with efforts undertaken in neighboring states and by the federal government. We then relate conjunctive use to the unconventional fuel industry and discuss how conjunctive use can help address pressing challenges. While conjunctive management cannot create water where none exists, it does hold promise to manage existing resources in a more efficient manner. Moreover, conjunctive management reflects an important trend in western water law that could provide benefit to those contemplating activities that require large-scale water development.