Editor’s Note: This piece is part of a four-part collaborative series between the University of Denver Water Law Review and the Stanford Environmental Law Journal that studies the public trust doctrine, the stark contrast of its history and development in Colorado and California, and the implications of its extension to groundwater.



A relic of antiquity, the public trust doctrine provides that “the state holds certain natural resources in trust for the benefit of its citizens.”[1] The state may provide for the private use of these resources, and allow private entities to obtain property rights in those resources, but the state must always ensure that the purposes of the trust are fulfilled.[2]

As a common law restraint, the doctrine prevents the diminishment of sovereign authority or the elimination public access to navigable waters and submerged lands.[3] Under its classic formulation in Illinois Central, the doctrine provides that the state is to hold title to the lands beneath navigable waters for the people, so that they may enjoy these waters free from the “interference of private parties.”[4] In Illinois Central, the United States Supreme Court explained that a state’s public trust duties can never be fully relinquished, likening obligations under the trust to a state’s immutable police powers.[5]

Although a state may not restrict the public trust doctrine, the doctrine may be expanded to meet the needs of an evolving community and the changing use of natural resources.[6] By the close of the twentieth century, many states had expanded the doctrine beyond its traditional focus on navigable waters to include lakes, tributaries, wetlands, and even groundwater.[7] In the 1970s, as the environmental movement rose to prominence, the doctrine took on additional significance in the world of legal academia.[8] Joseph Sax, a preeminent public trust scholar, was at the forefront of the move towards what has since been dubbed an “ecological” public trust doctrine.[9] Sax envisioned the doctrine as a tool by which judges could compel legislative consideration concerning actions harmful to trust resources.[10] By emphasizing judicial action, Sax believed that citizens could bypass legislatures and administrative agencies, which, according to Sax, had been corrupted by private agendas.[11]

In recent decades, there has been a continued debate over the applicability of the doctrine to the management of scarce western water. In Colorado, the public trust doctrine holds no legal authority.[12] Those arguing for the adoption of the doctrine, at least in reference to surface water and tributary groundwater, contend that the public trust doctrine should be applied more aggressively in the world of western water, and that the private property approach to water resources is inimical to solving issues of scarcity. By contrast, opponents caution against the enactment of a public trust doctrine, fearing the consequences such a wholesale adoption could have on water law in Colorado—a system that has been in place for more than a century. This article examines the history of the public trust doctrine in Colorado water law, discusses recent attempts to enact a public trust doctrine in the state, and briefly explains arguments for and against adoption of the doctrine within Colorado.


Water law in the American West is governed by the doctrine of prior appropriation, a legal system designed to facilitate the maximum use of a finite and scarce resource.[13] The doctrine of prior appropriation is characterized by the principle of “first in time, first in right”;[14] the first person to put a particular quantity of water to beneficial use acquires a paramount right to the continued use of that water.[15] Today, all western states adhere to some variant of the appropriative regime.[16]

In Colorado, the doctrine of appropriation inherited its purest form.[17] In response to the harsh realities faced by water users, the Colorado Constitution of 1876 declared that water from natural streams in the state will be “the property of the public,” and that the right to appropriate such water “for beneficial use in order of priority shall never be denied.”[18]   Central to the Colorado Doctrine is the principle that “priorities of right to the use of water are property rights.”[19] When a prospective appropriator diverts unappropriated water from a natural stream (or from tributary groundwater[20]) and puts it to a beneficial use, the private property right that results is a usufructuary right providing the appropriator with the right to use water that is owned by the state without corrupting its quality.[21] The resulting property right “is not an ownership right to molecules of water, but a right to divert a specified quantity of water for a specified ‘beneficial use with a specific priority relative to other users from the same source.’”[22] This right to use is a fully vested and alienable property right, which can be bought and sold without regard to the real property over which the water flows.[23] A priority right to the use of water, equivalent to a property right, is protected under the Colorado Constitution, meaning that no person can be deprived that right without due process of law.[24]


Article XVI, Section 5 of the Colorado Constitution states that “[t]he water of every natural stream . . . within the state of Colorado, is hereby declared to be the property of the public . . . subject to appropriation.”[25] Yet despite this provision, Colorado has not adopted the public trust doctrine, and the public interest is not considered during water adjudication proceedings.[26] The Colorado Supreme Court has opined that an objection to a decree based on public interest is invalid is directly in conflict with the doctrine of prior appropriation.[27] Questions regarding the public interest, the court explained, are the province of the General Assembly and the electorate, and are not an appropriate matter for courts to consider.[28] The Colorado Constitution requires only “protection for appropriation, not protection from use or for preservation.”[29]

Furthermore, while other states have adopted less stringent definitions of navigability, the Colorado Supreme Court has not declared any stream in the state as navigable. “[T]he Colorado Supreme Court long ago stated ‘[t]he natural streams of the state are nonnavigable within its limits.’”[30] While the court has not had an opportunity to directly confront the issue, it seems unlikely that the court would declare any stream within the state as navigable.[31]

While the Colorado Supreme Court has systematically rejected any attempt to enact a statewide public trust regime,[32] voters in Colorado can amend the state constitution through ballot initiative.[33] Over the last twenty years, there has been a concerted effort to force courts to recognize a public trust in surface water and tributary groundwater through that process, and these arguments are evocative of a much larger movement in the West.[34] Of paramount importance to those arguing for a robust public trust doctrine is the principle that certain public interests in natural resources are immune from private alienation, and should be protected as a communal resource.[35] Proponents argue that many of the virtues of the public trust doctrine—its ability to spur on legislative action and influence the reallocation of natural resources through judicial intervention—make it an ideal tool for addressing environmental concerns.[36] Moreover, because the doctrine affects a wide variety of natural resources, its potential for environmental preservation is tremendous.[37]   Supporters argue that “the heightened protection of water resources that attends broader application of the public trust doctrine could help slow the over-appropriation of vital waters, reacquire instream flows of such waters, and increase water conservation efforts.”[38] Proponents further contend that the doctrine can help reverse trends of environmental degradation and ongoing water scarcity, while a continued reliance on an appropriative regime will only accelerate these issues, by catering to special interests.[39]

In 2012, Richard Hamilton and Philip Doe proposed Ballot Initiatives 3 and 45, seeking to amend the Colorado Constitution in an effort to enact Colorado’s own variant of the public trust doctrine.[40] Hamilton has been the architect behind a series of ballot initiatives seeking to amend Colorado’s constitution to impose the public trust doctrine on the state’s water resources.[41] Whereas Initiative 45 sought to expand the scope of public control over all of the state’s waters, Initiative 3 was designed specifically to enact a Colorado public trust doctrine by adding language to article XVI, section 5 of Colorado’s constitution.[42] The third section of Initiative 3 provided that “the public’s estate in water in Colorado has a legal authority superior to rules and terms of contracts or property law.”[43] A later provision of Initiative 3 relating to state-owned water rights stated that “[w]ater rights, held by the state of Colorado for government operations, shall be held in trust for the public by the State of Colorado with the State acting as the steward of the public’s water estate.”[44]

Although the Colorado Supreme Court upheld the ballot title and submission clause for both of the 2012 proposed initiatives, neither measure obtained the requisite number of signatures to qualify for the statewide ballot.[45] In the case for Initiative 45, Justice Gregory Hobbs warned in his dissenting opinion against enacting a public trust doctrine. According to Justice Hobbs, if a public trust in water were enacted, “it would prevent farmers, cities, families and businesses from making beneficial use of water rights that have vested in them over the past 150 years under Colorado’s statutes and Constitution.”[46] The public’s dominant water estate would also supersede the Colorado Water Conservation Board’s appropriations for instream flows and lake level water rights, which are designed to protect the environment and recreational uses.[47] Moreover, it would inhibit Colorado’s ability to use the full extent of its allocations under various interstate compacts, resulting in a windfall to neighboring states.[48] Justice Hobbs concluded that adopting a public trust in water would “drop what amounts to a nuclear bomb on Colorado water rights.”[49]

Notably, Doe, together with Barbara Mills-Bria, is proposing a new public trust initiative in 2015–2016; the Colorado Supreme Court affirmed the Ballot Title Board’s approval of the ballot title and submission clause for “Initiative #4” on March 12, 2015, allowing the initiative to move forward and seek the requisite number of signatures to make it onto the 2016 state ballot.[50]

In response to those extolling the public trust doctrine for its ability to confront environmental concerns, others caution that environmentalism was not a function of the traditional public trust doctrine, and that “[e]xtension of the public trust doctrine . . . is judicial sleight of hand; its rationale (far afield from its roots) is that environmental concerns deserve the same nature and level of protection as public access to water bodies historically used for navigation.”[51] Opponents of the public trust doctrine acknowledged that while many environmental concerns are well-founded, “they are public policy goals best resolved by legislation after public debate, considering the most appropriate solution for each resource, with due regard for property rights.”[52]

In Colorado, most of the apprehension surrounding the public trust doctrine has centered on the consequences such a profound change would have on the Colorado Doctrine. Colorado has relied upon its current approach to water rights for over 150 years.[53] An initiative such as the one Hamilton and Doe advanced in 2012 would inevitably result in a dramatic increase in litigation over current water rights in the state.[54]

Opponents of the doctrine argue that imposing the public trust doctrine would place current water owners and users in Colorado in a precarious position, as their rights would be subject to potential alteration or revocation under a trust regime.[55] In addition, because water rights in Colorado are legally recognized property rights, any forced transfer of these rights resulting from a public trust regime could subject the state to takings liability.[56] Furthermore, a broad adoption of the public trust doctrine in Colorado could create enormous uncertainty in the water market by making it impossible for a user to plan or finance a significant water project and interfering with the ability of users to transfer water rights.[57] Finally, implementing a public trust doctrine would result in significant costs to the state. A study surrounding a 1996 initiative “estimated the very uncertain net fiscal impacts of the initiative to local governments in Colorado could range from $2.28 to $3.36 billion.”[58]


It seems unlikely that the public trust doctrine will ever be judicially enacted in Colorado, and it is uncertain whether it will ever be enacted through voter referendum. Nevertheless, the debate surrounding the public trust doctrine surges on, and Colorado continues to feel the pressure of those arguing for its adoption. Elsewhere in the American West, many have turned to the doctrine as the means by which to solve water scarcity and attendant environmental issues. However, Colorado remains steadfast in its reliance on its strict appropriative regime, and ballot initiatives attempting to introduce the public trust doctrine to Colorado remain the subjects of fierce objection.


[1] Dave Owen, The Mono Lake Case, The Public Trust Doctrine, and the Administrative State, 45 U.C. Davis L. Rev. 1099, 1107 (2012).

[2] Id.

[3] Stephen H. Leonhardt & Jessica J. Spuhler, 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. 47, 50 (2012).

[4] Ill. Cent. R.R. Co. v. Illinois, 146 U.S. 387, 452 (1892).

[5] Id. at 453–55.

[6] Julia K. Bramley, Supreme Foresight: Judicial Takings, Regulatory Takings, and the Public Trust Doctrine, 38 B.C. Envtl. Aff. L. Rev. 445, 456 (2011).

[7] Id. at 456; see also Order After Hearing on Cross Motions for Judgment on the Pleadings, Envtl. Law Found. v. State Water Resources Control Bd., No. 34-2010-80000583 (Cal. Super. Ct. Jul. 15, 2014).

[8] Russell M. McGlothlin & Scott S. Slater, No Fictions Required: Assessing the Public Trust Doctrine in Pursuit of Balanced Water Management, 17 U. Denv. Water L. Rev. 53, 60 (2013).

[9] Id. at 61.

[10] Id. (citing Joseph L. Sax, The Public Trust Doctrine in Natural Resource Law: Effective Judicial Intervention, 68 Mich. L. Rev. 471, 555–58 (1970)).

[11] Joseph L. Sax, The Public Trust Doctrine in Natural Resource Law: Effective Judicial Intervention, 68 Mich. L. Rev. 471, 560 (1970)

[12] See generally People v. Emmert, 597 P.2d 1025 (Colo. 1979) (establishing that Colorado waters are bound under the rule of private ownership, thereby rendering the public trust doctrine irrelevant, if not inoperable).

[13] Gregory J. Hobbs, Jr., Colorado Water Law: An Historical Overview, 1 U. Denv. Water L. Rev. 1, 2 (1998).

[14] German Ditch & Reservoir Co. v. Platte Valley Irrigation Co., 178 P. 896, 896 (Colo. 1919).

[15] A. Dan Tarlock, Prior Appropriation: Rule, Principle, or Rhetoric?, 76 N.D. L. Rev. 881, 882 (2000).

[16] Danielle Spiegel, Can the Public Trust Doctrine Save Western Groundwater?, 18 N.Y.U. Envtl. L.J. 412, 419 (2010).

[17] See Colo. Const. art. XVI, § 5; Leonhardt & Spuhler, supra note 3, at 50.

[18] Hobbs, supra note 13, at 6 (quoting Colo. Const. art. XVI, §§ 5–7).

[19] Nichols v. McIntosh, 34 P. 278, 280 (Colo. 1893).

[20] See Safranek v. Town of Limon, 228 P.2d 975 (Colo. 1951) (stating Colorado’s presumption of groundwater tributariness).

[21] Navajo Dev. Co. v. Sanderson, 655 P.2d 1374, 1377 (1982).

[22] Stephen N. Bretsen, Rainwater Harvesting Under Colorado’s Prior Appropriation Doctrine: Property Rights and Takings, 22 Fordham Envtl. L. Rev. 159, 182 (2011) (quoting George Vranesh, Vranesh’s Colorado Water Law 8 (James N. Corbridge & Teresa A. Rice eds., rev. ed. 1999)).

[23] Navajo Dev. Co., 655 P.2d at 1378.

[24] Nichols, 34 P. at 280.

[25] Colo. Const. art. XVI, § 5.

[26] Hobbs, supra note 13, at 22.

[27] Bd. of Cnty. Comm’rs v. United States, 891 P.2d 952, 972–73 (Colo. 1995).

[28] Id.

[29] Leonhardt & Spuhler, supra note 3, at 64.

[30] John R. Hill, Jr., The “Right” to Float Through Private Property in Colorado: Dispelling the Myth, 4 U. Denv. Water L. Rev. 331, 342 (2001) (quoting In re German Ditch & Reservoir Co., 139 P. 2, 9 (Colo. 1913)).

[31] Bd. of Cnty. Comm’rs, 891 P.2d at 972 (“Conceptually, a public interest theory is in conflict with the doctrine of prior appropriation because a water court cannot, in the absence of statutory authority, deny a legitimate appropriation based on public policy”).

[32] Leonhardt & Spuhler, supra note 3, at 49.

[33] Colo. Const. art. XIX, § 2.

[34] See, e.g., Carol Necole Brown, Drinking from a Deep Well: The Public Trust Doctrine and Western Water Law, 34 Fla. St. U. L. Rev. 1 (2006).

[35] Spiegel, supra note 16, at 429.

[36] McGlothlin & Slater, supra note 8, at 61–62 (citing Sax, supra note 10, at 555–58).

[37] Harrison C. Dunning, The Public Trust: A Fundamental Doctrine of American Property Law, 19 Envtl. L. 515, 517 (1989).

[38] Brown, supra note 34, at 9.

[39] Id. at 3 (explaining that the prior appropriation doctrine “was and still is a doctrine that caters to special interests such as development, mining, and agriculture”).

[40] Leonhardt & Spuhler, supra note 3, at 84; Kemper v. Hamilton (In re Title, Ballot Title, and Submission Clause for #3), 274 P.3d 562 (Colo. 2012); Kemper v. Hamilton (In re Title, Ballot Title, and Submission Clause for #45) 274 P.3d 576 (Colo. 2012).

[41] Id. at 81.

[42] In re Title for #45, 274 P.3d at 578; In re Title for #3, 274 P.3d at 564.

[43] In re Title for #3, 274 P.3d at 568.

[44] Id. at 569 (emphasis added).

[45] Leonhardt & Spuhler, supra note 3, at 84.

[46] In re Title for #45, 274 P.3d at 586 (Hobbs, J., dissenting).

[47] Id. (Hobbs, J., dissenting).

[48] Id. (Hobbs, J., dissenting).

[49] Id. (Hobbs, J., dissenting).

[50] See Order of Court, Kemper v. Doe (In re Title, Ballot Title, and Submission Clause for Proposed Initiatives 2015–2016 #4), No. 15SA15 (Colo. Mar. 12, 2015), available at https://www.courts.state.co.us/userfiles/file/Court_Probation/Supreme_Court/initiatives/2015-16/15SA15/3-12-15%20court%20order.pdf.

[51] Leonhardt & Spuhler, supra note 3, at 90.

[52] Id.

[53] Id.

[54] Id., at 88.

[55] Id. at 90.

[56] Id. at 94

[57] Id. at 89.

[58] Id. at 90.