2026 Symposium

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).

Last spring, my colleague wrote a post forecasting uncertainties surrounding the Post-2026 Operating Guidelines for the Colorado River Basin States’ negotiation. Now, just seven months later, the November deadline for state consensus regarding the Basin’s management has passed and precarity has compounded. Without an agreement by the new, February 14th, 2026 deadline, the federal government is slotted to assume a managerial role over the Basin’s water. While this outcome bears a familiar mark of uncertainty, it also carries major implications for the Tribal Nations that hold rights to the Basin. This post briefly summarizes the negotiations, their progression, and an important tribal consideration. To briefly refresh or acquaint new readers to this matter: the Post-2026 Operating Guidelines represent a complex management scheme for Lake Mead and Lake Powell’s water operations. In essence, the Guidelines determine how much water can be removed from the two reservoirs. Owing to the reservoirs’ ubiquity in the Western United States, these Guidelines will implicate the water rights of seven states and thirty Tribal Nations. The reality is multiple stakeholders divvy up a dwindling resource, negotiate slowly, and, resultingly, leave many unsure whether the States will reach consensus after recently missing the November 11 th deadline. Many variables factor into the stalling negotiations, including the Upper Basin’s reluctancy to accept water cuts and electoral accountability to respective state populaces. Important considerations for states with large tribal presences complicate these factors, like Arizona, where twenty-two of the Basin’s affected Tribes are located. While from the outset, several Tribes held senior water rights—entitling them to priority over junior right-holders—many Tribes have been forced to bargain away this advantageous position for much needed infrastructure. This phenomenon leaves Tribes within the Basin much more susceptible to State decisions to accept water cuts, hinging tribal access to the already scarce resource on interstate bargains like those now set to conclude in February. Together with the obvious challenges created by the missed deadline and fast-approaching February fallback, these dynamics create large obstacles for the Basin states as they look to reach consensus in the new year. Unfortunately, as so often occurs, tribal nations are left hanging in the balance awaiting state compromise. SOURCES  · Allie Parker, The Impacts of the Post-2026 Colorado River Discussions on Tribal Water Rights, U. Denv. Water L. Rev., (Apr. 3, 2025), https://www.duwaterlawreview.com/the-impacts-of-the-post-2026-colorado-river-discussions-on-tribal-water-rights . · U.S. Bureau of Reclamation, Colorado River Post 2026 Operations, https://www.usbr.gov/ColoradoRiverBasin/post2026/ (last visited Oct. 30, 2025). · The Colorado River, Post-2026 Negotiations, https://coloradoriver.com/post-2026-negotiations/ , (last visited Oct. 30, 2025). · Shannon Mullane, What’s holding up the Colorado River negotiations? Experts break down the sticking points, Colorado Sun (Oct. 30, 2025), https://coloradosun.com/2025/10/30/colorado-river-negotiations-experts-sticking-points/ . · Arizona Department of Education, 22 Federally Recognized Tribes in Arizona, https://www.azed.gov/oie/22-federally-recognized-tribes-arizona (last visited Oct. 29, 2025). · NRDC, Colorado River Basin Tribes Address a Historic Drought–and Their Water Rights–Head-On, https://www.nrdc.org/stories/colorado-river-basin-tribes-address-historic-drought-and-their-water-rights-head (last visited Oct. 30, 2025). · Michael Elizabeth Sakas, Historically excluded from Colorado River policy, tribes want a say in how the dwindling resource is used. Access to clean water is a start, CPR News, https://www.cpr.org/2021/12/07/tribes-historically-excluded-colorado-river-policy-use-want-say-clean-water-access/ (Dec. 7, 2021).