2026 Symposium

Colorado currently faces its lowest snowpack ever recorded. Following an unseasonably warm winter and hardly any snowfall, the Natural Resources Conservation Service reports snowpack at twenty-two percent of a normal year. At the same time, the Colorado River Basin states—Wyoming, Colorado, New Mexico, Utah, Arizona, Nevada, and California—are approaching their third year of renegotiating the most important water apportionment agreement in the American West: the Colorado River Compact. Originally negotiated in 1922 by delegates from all seven basin states and then-Secretary of Commerce Herbert Hoover, the Compact has governed the Colorado River’s use for over a century. In 1922, as now, the delegates understood the stakes. The river bound the region together, and the inhabitants of the basin states—both human and otherwise—built their lives around the river’s resources. Against this backdrop, the delegates waded through maps and then-available hydraulic data to equitably distribute a river that had already been allocated beyond its natural supply. They ultimately agreed to split the river’s flow roughly even between the Upper Basin and Lower Basin, measuring that split at Lees Ferry, Arizona. This required the upper states to allow seventy-five million acre-feet of water to flow down through Lees Ferry over a ten-year rolling average period. After setting that number, the delegates ratified the Compact and ended the states’ perpetual bickering over the river’s use, for the time being. Unfortunately for the century that followed, however, the Compact allocated water based on data from an unusually wet period in the West’s history. In other words, the Compact—at its inception—presumed a higher supply of water than the river typically carries. Compounding the problem, the basin’s current population—forty million people—is nearly twenty times what the delegates predicted back in 1922. These key misestimations show that the basin states’ current water use is already unsustainable. Now add this year’s record-low snowpack to the equation. Rocky Mountain snowpack typically accounts for approximately eighty percent of Upper Colorado River flow. When spring and summer hit, low snowpack in Colorado, Wyoming, and Utah will result in less water melting into streams and rivers. Notably, Colorado’s streamflow forecasts for 2026 predict below average snowmelt across all major river basins, which will cause significant water-level drops in the nation’s largest reservoirs—Lake Powell and Lake Mead. These conditions create untimely challenges for Compact renegotiations. Today, as in 1922, the renegotiation battle is split between the three Lower Basin states of California, Arizona, and Nevada and the four Upper Basin states of Wyoming, Colorado, New Mexico, and Utah. But the process is deadlocked, and Arizona delegates already anticipate complete failure. With the current conditions of the basin’s water supply, the upper states will fall below their obligatory seventy-five million acre-feet allotment to the lower states within the next two years. Failing to deliver that allotment will trigger a legal tripwire, allowing the lower states to sue for a violation of the Compact. But a lawsuit would spark a complex legal battle that could drag on for years, and interstate litigation would place the Compact in the federal courts’ hands, which is an outcome none of the states want. To avoid hitting that tripwire and hailing seven states into contentious litigation, the lower states are pushing for mandatory cuts on Upper Basin water use during these particularly dry years. Top Upper Basin negotiators countered, however, that mandatory cuts are not on the table. This places the Compact on a dangerously short timeline. Without substantial intervention, water levels will continue their downward trend, and reduced runoff from the Upper Basin’s snowpack may trigger the legal tripwire as early as this summer. The race is on to renegotiate the Compact before that happens. But with litigation looming and snowpack at historic lows, one thing is clear: the Colorado River is running low on both time and water. Sources: Alan Gionet, New Report Paints Grim Picture of Water Use Problems with Colorado River , CBS News (Dec. 26, 2025, 10:10 PM), https://www.cbsnews.com/colorado/news/new-report-colorado-river-water-use-dire-problems/ . Colo. River Compact (1922), https://www.usbr.gov/lc/region/g1000/pdfiles/crcompct.pdf . Colorado Snowpack Products , Nat. Res. Conservation Serv., https://www.wcc.nrcs.usda.gov/ftpref/support/states/CO/products/#state=co&element=wteq (last visited April 1, 2026). How Much Snow for Colorado River Flow? , Geosciences and Env’t Change Sci. Ctr., https://www.usgs.gov/centers/geosciences-and-environmental-change-science-center/science/how-much-snow-colorado-river#overview (last visited March 15, 2026). Ian James, How Failing Negotiations Could Spiral into a Bitter Fight over the Colorado River , L.A. Times (Feb. 5, 2026, 10:29 AM), https://www.latimes.com/environment/story/2026-02-05/colorado-river-negotiations-failing . Jake Bolster and Wyatt Myskow, Colorado River Negotiators Are Nearly Out of Time and Snowpack , Inside Climate News (Feb. 4, 2026), https://insideclimatenews.org/news/04022026/colorado-river-record-low-snow-litigation/ . Maddie Rhodes, This Winter has the Lowest Snowpack so far in Colorado History , Fox31 Denver: Weather Headlines (Feb. 5, 2026, 11:44 AM), https://kdvr.com/weather/wx-news/this-winter-has-the-lowest-snowpack-so-far-in-colorado-history/ . Margaret Osborne, A Century Ago, this Water Agreement Changes the West. Now, the Region is in Crisis , Smithsonian Magazine (Nov. 28, 2022), https://www.smithsonianmag.com/smart-news/a-century-ago-this-water-agreement-changed-the-west-now-the-region-is-in-crisis-180981169/ . Mike Lee and Martin Heinrich, Colorado River Talks: Securing Water for the West , The Hill (Dec. 19, 2025, 10:30 AM), https://thehill.com/opinion/energy-environment/5654255-future-colorado-river-agreement/ . Record Low Snowpack Observed Across Much of Colorado Heading into 2026 , Nat. Res. Conservation Serv., https://www.nrcs.usda.gov/state-offices/colorado/news/record-low-snowpack-observed-across-much-of-colorado-heading-into-2026 (last visited March 15, 2026). Shannon Mullane, Colorado River Negotiations in Murky Waters after Historic Gathering of Governors in DC , The Colorado Sun (Feb. 3, 2026, 3:51 AM), https://coloradosun.com/2026/02/03/colorado-river-governor-negotiations-dc-water-congress/ . Steve Harris, How Did Compact Negotiators Split the Colorado River’s Flow in 1922? , The Rocky Mountain Voice (Oct. 9, 2025), https://rockymountainvoice.com/2025/10/09/how-did-compact-negotiators-split-the-colorado-rivers-flow-in-1922/ .

Introduction The public trust doctrine (the “Doctrine”) evolved from a form of governmental authority over specific natural resources—primarily waterways—to compelling the state to manage certain common natural resources in trust for the public. Nowadays, the public trust doctrine is a method of environmental advocacy in the United States. The Doctrine spanned both an unsuccessful attempt to compel a state to limit fossil fuel use and a successful effort to restore waters in a depleting lake. Additionally, there is continued interest in using the Doctrine to increase recreational access. This post first explores the public trust doctrine’s evolution, from its origins in Roman law to its incorporation into English common law, and then to its transformation into the modern American public trust doctrine. It then explores how the public trust doctrine influenced water law in Idaho and Montana, and the two states’ different approaches to public recreational access to waters despite laws originating from the same doctrine. Overall, Idaho is more restrictive with public recreational access to waters. In contrast, Montana allows for broader public recreational access to waters. I. History of the Public Trust Doctrine Modern historians credit the origin of public trust doctrine to the Justinian Codex, which stated running water, the shores, and the sea are common property to the public. This jus publicum concept from Roman law survived, eventually taking root in English law. A similar concept is first found in the Magna Carta, which declared the Thames and Medway Rivers navigable waters and public commons for fishing or navigation. The Doctrine then formally took hold in English common law in the 17 th century when the King’s Bench held “sovereign ownership” applied to tidelands, and navigable waters were for public use. After the Revolutionary War, the thirteen original states succeeded the Crown in ownership of tidelands, becoming the new ‘sovereigns’ of America. In the early 19 th century, Arnold v. Mundy reaffirmed the Doctrine. The plaintiff claimed the defendant trespassed on his private oyster bed and took the plaintiff’s oysters. The defendant, in response, claimed he only took the oysters below the high water mark in a tidal, navigable river. The court, siding with the defendant, held navigable rivers, along with the coasts, were “common” to all the citizens for fishing, passing, and navigation. This holding also extended to the land under the water. Martin v. Waddell, another oyster farm dispute, affirmed Arnold’s holding. Three years after Martin, the Supreme Court held in Pollard’s Lessee v. Hagan that because new states were admitted to the union “on equal footing” as the original states, the new states received the same rights as the original thirteen states. Thus, any new state received an automatic transfer of title to lands underlying navigable waters at the time of statehood. Propeller Genesee Chief v. Fitzhugh then held that state ownership expanded to navigable, non-tidal waters and their beds. Later, the Supreme Court released The Daniel Ball test, the federal test for navigability. The Daniel Ball test states that waters are navigable when they are used as highways for commerce, over which customary trade and travel may be conducted. By the mid 19 th century, American law well established that states were presumed to hold title to both the beds, banks, and surface of navigable streams. In the late 19 th century, the Supreme Court decided the Doctrine’s seminal case: Illinois Central Railroad Co. v. Illinois. The Illinois legislature granted the Railroad 1,000 thousand acres of submerged land beneath the Chicago waterfront. Later, the legislature attempted to rescind the grant, leading to the lawsuit. The Court concluded a state cannot transfer lands under navigable waters to private parties, as it holds them in trust for the public for fishing, navigation, and commerce. Illinois Central not only affirmed state authority over submerged beds, but also established the idea the state was a trustee for the public of the submerged lands, and private parties could not “obstruct” the public’s access to fishing, navigation, or commerce. Shively v. Bowlby then followed, affirming Illinois Central’s holding. Shively also added that each individual state’s laws govern public trust waters. Once a concept of Roman and English law evolved into American’s modern public trust doctrine: under each state’s laws, the state, as trustee for the public, owns the beds of navigable rivers and tidelands. These trusts open to the public for commerce, navigation, and fishing. II. The Public Trust Doctrine Relating to Idaho's Recreational Access Idaho follows the public trust doctrine and allows recreational access to navigable waterways. However, if the waterway is non navigable, recreational access is not allowed, as it is deemed private property. Idaho’s constitution declares: “ all water originally appropriated for private use, but which after such appropriation has heretofore been … is hereby declared to be a public use, and subject to the regulations and control of the state.” The Idaho Supreme Court held in Callahan v. Price that Idaho holds title to submerged lands of navigable waterways. To determine what waters and submerged beds are under state control, Idaho uses the federal test of navigability. Originally, Idaho’s public trust doctrine only covered navigation, but has been expanded to recreation. Earlier caselaw out of the Idaho Supreme Court supported recreational access: Southern Idaho Fish and Game Association v. Picabo Livestock, Inc., upheld public access to the beds of navigable streams, and Kootenai Environmental Alliance, Inc. v. Panhandle Yacht Club, Inc., upheld the state has title to the beds of all navigable bodies of water below the natural high-water mark. However, earlier caselaw also upheld private ownership of non-navigable stream beds. Mesenbrink v. Hosterman reaffirmed the principle that riparian landowners also owned the beds of non-navigable bodies of water and treats unauthorized access to water as a trespass. In 1996, Idaho codified— and limited—the public trust doctrine in the Public Trust Doctrine Act (“PDTA”). The PDTA codifies Idaho’s waters as held in the public trust, and includes recreation as a suitable purpose. III. The Public Trust Doctrine Relating to Montana's Recreational Access Montana’s constitution enshrines the public trust doctrine: “ All surface, underground, flood, and atmospheric waters within the boundaries of the state are the property of the state for the use of its people and are subject to appropriation for beneficial uses as provided by law.” The Supreme Court of Montana, in Montana Coalition for Stream Access, Inc. v. Curran, decided against using The Daniel Ball test to determine public access to waters, and instead held that if a waterway was used for recreational boating rather than as highways for commerce, the water will still be considered navigable. Later in the opinion, the court decided the ownership of the streambed to be irrelevant, and the public can access public waters up to the high water mark. Further, the Doctrine, along with Montana’s constitution, do not allow a private party to “interfere” with public recreational access of the state’s waters. Montana Coalition for Stream Access, Inc. v. Hildreth soon followed, reaffirming Curran’s holding and cementing public recreational access to waters within Montanan law. In response to these decisions, the Montana legislature passed the Stream Access Laws (“SAL”) which codified the public’s right to recreate in waters regardless of public or private ownership of the land underlying the waters. Within the SAL, Montana divides recreational waters into two categories: Class I and Class II waters. Class I waters are types of navigable surface waters, determined either by the federal navigability test, or are waters capable of log floating or transportation of furs and skins. Class II waters are any other type of water, except for lakes. Galt v. State upheld these classifications, affirming both classifications of waters are for public recreational access. Overall, Montana’s recreational access can be summarized to allow recreation on any surface water without regard to public or private ownership or whether the surface water is navigable. Conclusion Differences in public recreational access to waters in Idaho and Montana stem from variations in their constitutions, case law, statutory codifications of the public trust doctrine, and the extent to which each state relies on the federal navigability test. Idaho’s constitution declares “water is originally appropriated for private use.” This is then followed by the language “waters after appropriation” are for public use. Through statutory interpretation, a reasonable person can determine that Idaho’s constitution prioritizes private ownership, as water is first mentioned for private use, and, following appropriation, can then be used for public use. In contrast, Montana’s constitution declares “all” waters are for public use, which is then followed by the language “subject to appropriation.” Montana’s constitution prioritizes public ownership, as ‘all’ water is first mentioned for public use, after which it can be “appropriated” for private use. Idaho follows the federal navigability test to determine public or private ownership of the waters, which then determines whether public recreational access is allowed. On navigable rivers, Idaho allows public recreational access, since the state owns the waters and submerged beds. On non-navigable rivers, Idaho does not allow public recreational access, since the littoral landowner owns both the waters and submerged beds. Montana disregards the federal navigability test to determine ownership of submerged lands. Both navigable and non-navigable rivers are open to public recreation, as to the ownership of the streambeds is irrelevant.  Additionally, Idaho codified the public trust doctrine in the PDTA, while Montana codified it in the SLA. On one hand, the PDTA explicitly limits the public trust doctrine. On the other hand, the SLA expands recreational access to waters, thereby expanding the public trust doctrine. Sources: Erin Ryan, A Short History of the Public Trust Doctrine and its Intersection with Private Water Law, 39 Vir. Envtl. L. J. 135, 137 (2020) Juliana v. United States, 947 F.3d 1159 (9th Cir. 2020) National Audubon Society v. Superior Court of Alpine County, 658 P.2d 709 (Cal. 1983) Cert denied, 464 U.S. 977. Ralph W. Johnson and Russell A. Austin Jr., Recreational Rights and Titles to Beds on Western Lakes and Streams, 7 Nat. Res. J. 1 (1967) The Public Trust Doctrine: What it is, Where it Came from, and Why Colorado Does Not (And Should Not) Have One: 16 U. Denv. Water L. Rev. 17 (2012). Justinian, the Institutes of Justinian 2.1.1 (Thomas Cooper trans. & ed. 1841). Arnold v. Mundy, 6 N.J.L 1 (N.J. 1821). Pollard’s Lessee v. Hagan, 44 U.S. 212, 222 (1845). Reed D. Benson, Burke W. Griggs, & A. Dan Tarlock Water Resource Management: A Casebook in Law and Public Policy at 521 (Foundation Press, 8th ed. 2021). The Daniel Ball, 77 U.S. (10 Wall.) 557 (1870). Illinois Central Railroad Co. v. Illinois, 146 U.S. 387, 452 (1892) Joseph L. Sax, The Public Trust Doctrine in Natural Resource Law: Effective Judicial Intervention, 68 Mich L. Rev. 471, 478 (1970) Shively v. Bowlby, 152 U.S. 1, 26 (1894). 26 Idaho Const. Art. XV § 1. Callahan v. Price, 146 P. 732, 735 (Idaho 1915). Idaho Code § 58-202 (1996) (referencing The Daniel Ball Test). Newton v. MJK/BJK, LLC, 469 P.3d 23, 29 (Idaho 2020) (referencing Idaho Forest Indus., Inc. v. Hayden Lake Watershed Improvement Dist., 733 P.2d 733, 737 (1987)). Southern Idaho Fish and Game Association v. Picabo Livestock, Inc., 528 P. 2d 1295 (Idaho 1974) Ritter v. Standal, 566 P.2d 769 (Idaho 1977) Kootenai Environmental Alliance, Inc v. Panhandle Yacht Club, Inc., 671 P.2d 1085 (Idaho 1983) Mesenbrink v. Hosterman, 210 P.3d 516, 520 (Idaho 2009) (reaffirming Callahan v. Price, 146 P. 732, 735 (Idaho 1915)). Idaho Code § 58-1201(6) (1996). Idaho Code § 58-1203(3) (1996). Mont. Const. Art. IX. § 3(3). Montana Coalition for Stream Access, Inc. v. Curran, 682 P.2d 163, 169 (Mont. 1984) (quoting Lamprey v. Metcalf, 53 N.W. 1139, 1143 (Minn. 1893)). Mont. Code Ann. § 23-2-302(1) (1985). Mont. Code Ann. § 23-2-301(2) (1985). Mont. Code Ann. § 23-2-301(2)(3) (1985). Galt v. State, 731 P.2d 912, 915 (Mont. 1987) In re Adjudication of Existing Rights to the Use of all Water, 55 P.3d 396, 404 (Mont. 2002).