Summary

The concept of a uniform U.S. water policy is a fallacy, instead resembling a mythological hydra with three primary necks that broadly encapsulate the following topics: (a) water usage patterns and demands, (b) governance structures (legal and economic), and (c) evolving scientific information and analysis (projection, planning, etc.). The body, feet, and tail of the policy and planning hydra are the physical hydrologic reality of natural and built systems, responding to the heads’ decisions. During the 20^th and early 21^st centuries, the hydra was governed by concepts of stationarity maintenance in each of the necks, with devolved and pragmatic fragmentation in the governance and scientific information and analysis necks, as follows. Water supply achieves stationarity through physical storage and centralized infrastructure; federal engineers altered hydrologic systems for flood control, more consistent water supply, and transportation/commerce. Water governance increasingly fragmented from the heterogeneity of water users’ interests, authority, and separation between water quality and quantity. Water law and economics coevolved to buffer demand’s nonstationarity. Planning responsibility shifted from federal agencies to states, with guidance from the country’s closest effort to manifest a unified national water policy through the National Water Commission’s 1973 report recommendations, despite its lack of official enactment. Stationarity negatively impacted aquatic ecosystems through dam flow alteration, omission in water use accounting, lack of legal protection in state allocation structures, lack of a market value, and only early 21st century inclusion in federal, state, and local water planning. Climate change further stresses these existing flaws in social and physical water management systems and processes. Its extremity in the body of the hydra reverberates through each of the necks and heads in variable ways, upending stationarity and challenging already fragmentated governance capacity. Policy and planning face greater uncertainty by geographic area, necessitating adaptive water management. Water managers must ubiquitously realize greater efficiency through innovative demand reduction mechanisms and decentralized infrastructure that can withstand significant hydrological cycle alterations, including changes to peak flow and more substantial reservoir evaporation outside the stationarity envelope. Climate adaptation in water law will require additional sacrifice concurrent with the early 21st century legal allocation and acknowledgement of historically marginalized water rights. Planning approaches must increase their flexibility, relying more heavily on water governance that embraces a cooperative, holistic perspective, recognizing interreliance and connectivity to increase resilience. The federal Infrastructure Investment and Jobs Act of 2021 may be the first step toward a unified national water policy since the 1973 report. Climate change forces the question of whether to cede full water management authority to the federal government or to sustain the creative and localized solutions fomented by pragmatic federalism.