ENVIRONMENTAL FLOWS AND WATER REGULATION IN THE U.S. AND THE WORLD: A CALL TO ACTION FOR HYDROGEOLOGISTS

As conflicts between ecosystems and human needs for freshwater are increasing, transitioning to instream flow protection and generally incorporating environmental goals in water management are becoming increasingly difficult. Following a brief outline of the state of freshwater ecosystems, this presentation points out that ground water is a key component of instream or environmental flows and thus hydrogeologists should be more involved in the ongoing debates about maintaining healthy riverine ecosystems. Environmental flows protection is an emerging concern particularly in the western U.S., where instream flow programs are largely conditioned by the water-rights system in which they are operational. Instream flow water-rights designations often have such a low priority date that they do not offer much protection to rivers and streams. While the prior appropriation doctrine is the common denominator in western U.S. water law, individual states differ appreciably in the mechanisms available for the protection of instream flows. Promising opportunities for achieving instream flows in both under-allocated and over-allocated basins are outlined, and new methods in protecting fresh-water ecosystems are summarized. Instream flow protection measures include private water trusts, “upside-down instream flow water rights,” the “public trust” doctrine, and water markets. Environmental flows must be seen within the context of applying integrated/conjunctive use water resource management in river basins. A number of knowledge gaps are identified, to which hydrogeologists in particular could contribute, such as our rudimentary knowledge of Groundwater-Dependent Ecosystems, aspects of stream-aquifer interactions, and the impacts of land use changes. The values that society places on the different uses of water ultimately determine where the water is allocated. Environmental flow requirements can be legitimately recognized and addressed by basing the environmental needs of hydrologic systems on rigorous science, focusing on increasing the productivity of water use, engaging society in understanding the benefits and costs of decisions that affect ecosystems, and taking advantage of various opportunities for achieving environmental flow goals.