On the eve of the third decade of the 21st century, the global water crisis has become existential—a crisis that has and will test the law of water, private landowners, citizens, communities, states, and countries who seek to compete for control of water for their needs and the existence of life itself. We live in inseparable arcs of a water cycle—the watershed where we live and the hydrosphere. Until the end of the 20th century, the law struggled to conform to this reality. While the legal rules for lakes, streams, and groundwater are often separate and disparate, the modern sciences of hydrology, geology, and ecosystems have pointed the courts and law toward a more holistic understanding of water, human uses of and needs for it, and the life that depends on it. Courts are now catching up to the reality that if the law does not look at the cause and effect of human activities impacting every facet of the water cycle, the law will not protect the whole—the public water commons—on which all life depends.
Water as part of the commons
Water has been categorized as a public, common resource for over 1,500 years. Human uses first centered around drinking, hunting and gathering, and food for survival. Hunting and gathering cultures engaged in subsistence farming. Villages and towns grew into large cities and civilizations, such as Ur, Persia, and Samaria in the Fertile Crescent, from 3,000 to 4,000 B.C. Like modern times, ancient civilizations harnessed and diverted water through extensive networks of canals to divert and control rivers for massive irrigation works.
These techniques soon spread throughout the Mediterranean, Asia, and Europe. The Roman Empire constructed aqueducts to foster the power, commerce, and pleasure of Rome. The Justinian Code, compiled from 529–534 C.E., embedded into the law the importance of water as a resource held in common by all citizens:
Those things not divided [owned] by individuals still belong to the nation for the benefit of all citizens . . . . Others remain common to all citizens, who take of them and use them, each according to their necessities, and are called common property. Of this latter kind . . . are the air, the running water, the sea, the fish, and the wild beasts.
A few hundred years later, in 1215, the Magna Carta forced the English Crown to remove the exclusive weirs for fishing and navigation that had been transferred to favored royalty, and return the rights of fishing and sustenance in tidal waters and rivers to the people.
After the American Revolution, the U.S. Supreme Court adopted the “equal footing” doctrine, holding that upon admission to the Union, each state as sovereign received title to all navigable waters within their boundaries, as well as the submerged lands beneath those waters, in trust for its citizens. In 1821, in Arnold v. Mundy, the New Jersey Supreme Court ruled that water was held by the state as common public property, voiding the reliance of a riparian landowner on a grant from the Crown to control the oyster beds below the high-water mark. 6 N.J. 1 (1821). In 1892, the U.S. Supreme Court in Illinois Central Railroad v. Illinois—known as the “lodestar” of public trust law—voided a grant of nearly one-square mile of Lake Michigan on the shores of Chicago to a railroad company for its private gain. 146 U.S. 387 (1892). The Court reasoned that, pursuant to the public trust doctrine, the grant had unlawfully alienated and impaired the rights of citizens to fish, navigate, and sustain themselves.
Water as property right
The right to use water has also been conceptualized as a property right. Unlike water that passed from the Crown to the colonies (and from the colonies to the states) as a commons, land devolved to the states as property, carrying with it the rights of transfer, exclusive possession, and a “bundle of sticks,” or rights to use to benefit the land of the owner. Ownership of land adjacent to a lake or stream carried with it the right to use the water to benefit the use and enjoyment of the land. Such rights are known as “riparian” rights. Ownership of land also carried with it the right to use the underlying or percolating groundwater to benefit the land. Under the Fifth and Fourteenth Amendments to the Constitution, no person can be deprived the right to “life, liberty, and property,” including the private rights in or the use of water under the law of each state. As a result, common law water rights may generally not be categorically taken. Lucas v. S. Carolina Coastal Council, 505 U.S. 1003 (1992). That said, some water rights or uses may be limited so long as the regulation does not “go too far” in limiting a use to achieve a public purpose, without compensation, subject to the limitations inherent in the background principles of property law, such as nuisance law and the public trust doctrine. Pennsylvania Coal Co. v. Mahon, 260 U.S. 393, 415 (1922); Lucas, 505 U.S. at 1029–30; see also Just v. Marinette County, 201 N.W. 2d 761 (Wisc. 1972).
The tension between private rights and public water commons
These disparate methods of conceptualizing water rights can come into conflict. As can be seen in figure 1, the more we weaken the standards for the common law riparian and groundwater rights to divert, sever, or remove water from a watercourse, the greater the loss or harm to the public water commons. Conversely, the more we protect the integrity of the water commons, the greater the restriction on private rights to use water. However, the integrity of the water commons is often paramount. If the exercise of a private water right interferes with common law principles such as the public trust doctrine or public rights of navigation, fishing, or beach-walking, the private right must yield.
Limitations on diversions that affect public water
Courts are becoming more adept at resolving tensions related to water uses. More and more frequently, courts are perceiving a nexus between the use, diversion, or impact to groundwater and hydrologically connected public water and the public trust doctrine.
For example, in 1983, in National Audubon v. Superior Court, the California Supreme Court limited a diversion from one aspect of the water cycle where that diversion interfered with the public rights to another aspect of the water cycle. 189 Cal. Rptr. 436, 446, 658 P.2d 709 (Cal. 1983). The court ruled that a permitted diversion of water from an unnavigable stream tributary to Mono Lake could be limited because it reduced the water level and interfered with the common public trust waters of Mono Lake. In Environmental Law Foundation v. State Water Resources Control Board, 26 Cal. App. 5th 844 (2018), the California Court of Appeal ruled that the public trust doctrine applied to groundwater withdrawals.
More recently, courts have extended the limitation on diversions for tributary streams to groundwater. In a series of cases, Hawaiian state courts have limited the diversion of groundwater where the diversion impacts public waters under the public trust doctrine and the state constitution. In re Water User Permit Applications for the Waiahole Ditch, 9 P.3d 409, 455 (Haw. 2000); Hawai’i Const. Art XI, sec. 1; In re Waiola Molokai, Inc., 83 P.3d 664 (Haw. 2004)); ‘Iao Groundwater Management Area Permit Applications, 287 P.3d 129 (Haw. 2012).
The Supreme Court of Wisconsin has also set aside and remanded the approval of a municipal water supply groundwater withdrawal permit issued by the state’s Department of Natural Resources because the permit failed to fulfill the Department’s public trust duty to consider the effects on an adjacent lake. Lake Beulah Water Mgmt. Dist. v. State Dep. of Nat’l Res., 799 N.W. 2d 73, 76 (Wis. 2011). And following the extension of public trust protection to prevent diversion of tributary streams, California state courts have affirmed that any allocation of water, without distinction between tributary streams or groundwater, is limited by legally required considerations of impairment or impacts on protected public trust waters and wildlife. National Audubon, supra, 189 Cal. Rptr. at 446; Ctr. for Biological Diversity v. FPL Grp., Inc., 166 Cal. App. 4th 1349, 1366 (2008) (affirmative public trust duty on state to consider effects of decisions on wildlife).
To round out new contours of legal limits on diversions from public waters, agreements by states, like the Great Lakes Compact, have declared water a single hydrologic system held in trust and prohibited diversions, subject to narrow exceptions. Great Lakes-St. Lawrence River Basin Water Resources Compact, § 4.8, 4.9, Dec. 13, 2005, available at https://www.gsgp.org/media/1330/great_lakes-st_lawrence_river_basin_water_resources_compact.pdf. States have done so because the Great Lakes—which hold 20 percent of the world’s fresh surface water—are held in trust. Id. § 1.3(1)(a).
Meanwhile, several courts have recognized a claim for violation of the public trust caused by the alternation or “diversion” of public trust waters flowing from human-induced climate change. If the public trust is applied to the entirety of the water cycle, private water diversions, including the causal effect of climate change on public trust resources and uses, should be inherently limited to protect the integrity of protected public trust navigable waters and the environmental values and public trust uses dependent on those waters. Juliana v. United States, 947 F.3d. 1159, 1168–69 (2020) (recognized constitutional claim for injury based on causal connection between climate change and harm to specific public trust uses by plaintiffs, but determining plaintiffs failed to show standing because they lacked an effective remedy). All life, even the lives of those intending to benefit from diverting water, depends on the integrity of public trust waters.