Climate change poses challenges for Wyoming water law, seen these days on the Grand Encampment River southwest of Saratoga.


The Encampment River valley is like many small, irrigated valleys in Wyoming. It was once the home of a few pioneer ranches that built a network of ditches, but the ranches have been divided up, the river has moved over time, and people have kept irrigating using the old ditches, sometimes with a little jerry-rigging. The Encampment valley is also narrow, with usually more than enough water, so state water officials haven’t had to “regulate” to keep water use in line with water rights. 

Enter the Sinclair Refinery near Rawlins, Carbon County’s biggest employer. Its workforce includes people from the Encampment valley, located some 40 miles away. In just the last year and a half, the oil company that took over the refinery bought a ranch on the Grand Encampment River.

The attraction: the old water rights on the ranch. The goal: to bolster the refinery’s water supply in the face of climate change.

Six times in the last 20 years, including 2022, the Upper North Platte Basin
has seen climate change in low snowpack. It has meant that in spring, the
refinery couldn’t legally use its own 100-year-old water rights. Refinery
managers had to arrange for temporary use of older water rights from
elsewhere. Buying the Encampment ranch offers the new refinery’s owners,
called HF Sinclair, a more permanent solution for those low snow-pack years. 

That has some neighbors worried. Now, how water works in the Encampment valley — which lands are irrigated or not, when and through what ditch — must be examined. 

It might seem neighboring irrigators wouldn’t care if a ranch won’t use its water rights in some years. But in a classic Wyoming spot like the Encampment valley, where the water rights and ditches and the irrigation practices and the water table and the water runoff from irrigation are interwoven, the refinery’s water use could disrupt the current pattern. 

The HollyFrontier Sinclair refinery in Sinclair, Wyoming as seen in July 2011. (James St. John/FlickrCC)

HF Sinclair’s plan will test the capacity of Wyoming water law to serve both the refinery and the Encampment irrigation community in the era of climate change. Will water officials’ decisions start to unravel the fabric of the community, as some fear, or will it leave that fabric substantially intact?

Most climate change headlines in Wyoming have focused on the Colorado River Basin, but the Upper North Platte River Basin — embracing both the Sinclair refinery on the North Platte and the Encampment River, a North Platte tributary upstream — has also gotten steadily hotter in the last 20 years.

HF Sinclair’s proposal to move water rights from one location to another — in response to the impending climate crisis — is a prospect that has long alarmed Wyoming irrigators. The fear is that “drying up” a ranch can damage local economies. Such moves were once mostly illegal in Wyoming, and many irrigators believe they still are. But 50 years ago in another national crisis — rising energy prices, creating demand for power plants in Wyoming — the state changed its law to allow such moves if they meet strict standards. There must, for instance, be proof of how much water was consumed at the original spot — no more can be consumed at the new spot, and the amount of water that used to return to the stream from the original irrigation must be left in the stream at that point. 

Notably, HF Sinclair is not proposing to dry up its ranch with any such permanent move of water rights. Only in low snowpack years would the refinery activate a new arrangement — a proposed “exchange.” The plan is that in those years the refinery would legally get to use its rights on the North Platte despite low flows, while it would not irrigate its Encampment ranch at all in spring or summer. That would allow Encampment water unused at the ranch to flow down the North Platte to Pathfinder Reservoir as “makeup” water, as required by the Wyoming water exchange law. 

HF Sinclair also says it will invest in the interconnected headgate and ditch system on the Encampment to make sure that when the ranch does not tap the Encampment River at all for a year, neighbors still get water for their rights.

There is heavy pressure for an uncomplicated review of HF Sinclair’s plan. The company does not hesitate to underline the implications for sustaining local jobs. To get approval, the company has hired a phalanx of high-powered law and technical people, including a former Wyoming State Engineer.

But leading irrigators on the Encampment have asked state officials for a thorough review — they don’t, however, want the cost and trouble of hiring lawyers and engineers to fall on them. The Wyoming Stock Growers, meanwhile, this summer called for public meetings on water changes as a review of Sinclair’s plans got underway.

Neighbors don’t have grounds to complain if a ranch just decides not to irrigate in a few years. But because HF Sinclair is proposing a legal change, the ranch neighbors have brought concerns to the state water officials who must decide whether to approve the exchange.

To get that approval, HF Sinclair must take two steps: first clean up the water rights on the ranch, and then get the exchange petition granted.

Cleanups are standard in places like the Encampment River, since actual use of old water rights in Wyoming often changes over decades, as streams move a little and ditches fall into disuse. Often old water rights must be identified and nailed down to the current use, at the expense of the right-holder. Sometimes, cleanups get complicated. The strict standards of Wyoming’s water-moves law can apply, if change over time includes water moving some distance. 

HF Sinclair is asking for a simple cleanup, which could avoid that scrutiny. The company has filed documents to show that only relatively insignificant changes in irrigation have taken place in over a century of ranch operations — nothing that should invoke the scrutiny required for serious movements of water rights. 

There are, of course, all kinds of questions that could arise in HF Sinclair’s cleanup: How much of the ranch’s Encampment River rights have actually been used, where and from what headgates? Does the groundwater level in low-lying lands mean that water consumption there can’t really be stopped, and maybe fields there haven’t required much irrigation water? Has enough irrigation water been used on other ranch fields to provide the proposed “makeup” water for the exchange? 

How intensely to review HF Sinclair’s cleanup is a decision for the state Board of Control (the State Engineer and the superintendents of Wyoming’s four geographical water divisions). Then HG Sinclair’s separate request for an exchange – a transaction expressly encouraged by state law – goes to the State Engineer alone to decide.

It will take months or years to see how Wyoming’s water rights review process plays out in this case. And the practical impact may finally depend on how many low snowpack years the future holds for the North Platte Basin. But ultimately, what happens on the Encampment will say a lot about how the state’s water law system will handle the pressures on water that are brought by climate change. 

Relatively smooth approval of an exchange on the Encampment could encourage towns and industries in Wyoming’s Green and Little Snake River basins to seek their own exchanges. For them, exchanges could be a solution to water supply shutdowns threatened by climate change on the Colorado River. In recent years the State Engineer’s Office has suggested that exchanges could be useful for that purpose, using reservoirs as makeup water.

But ultimately, what happens on the Encampment will say a lot about how the state’s water law system will handle the pressures on water that are brought by climate change. 

On the Encampment, HF Sinclair’s experts include former State Engineer Pat Tyrrell, former Division I Water Superintendent Brian Pugsley, and veteran water lawyer Dave Palmerlee.

The facts on the ground may well be such that the refinery’s proposal would easily survive any tough scrutiny. But the way the consultants have couched the requests makes it appear they’re betting they won’t trigger that kind of review, so they get approval — and relatively quickly.

The Encampment community’s fear of local damage has brought an audience to the normally unnoticed Board of Control meetings, however.

Nearby ranchers would like to see Sinclair offer a signed contract for the investment in headgates and ditches to secure access to all neighbors’ water rights. They don’t want to contend with Sinclair’s experts in formal hearings or appeals. But they do want a very careful state review.

Correction: Information about the number of low snowpack years was corrected. —Ed. 

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  1. With regard to Anne McKinnon’s article (Wyofile 9/23/2023), “How does water law handle climate change? Watch the Encampment River”, some additional background might be informative.

    Ranches, like ours, immediately downstream, and down-ditch, from the Sinclair ranch where Sinclair holds appropriations from the Encampment River also hold appropriated water rights. Originally, both ranches had the same owner and many of the current irrigating systems were developed (by our ancestors) in the 1880s and 1890s to irrigate all the land by diverting water from the same streams, ditches, diversions and means of irrigating.

    As the land was broken up into separate ranches and smaller parcels, the applicable water rights followed the land parcels that were sold and the old systems mostly continued to work, with few changes, to the benefit of all appropriators.

    Now, Sinclair wants to get state approval to exchange its right to use the appropriations on its ranch for the right to use the water at its refinery, some 30 miles downstream, during certain low water years when its current refinery appropriation is temporarily restricted from use by a settlement of North Platte River litigation in the late 1990s to benefit major reservoirs downstream. The water Sinclair proposes to transfer from its ranch is not subject to the restriction, and would enable Sinclair to avoid a shortage during such restrictions. In years when use of Sinclair’s current water use is not restricted, the exchanged water rights would revert to the upstream ranch. Such a back-and-forth movement of an appropriated water right under this exchange procedure is not believed to have previously been accomplished under the exchange statute referenced below.

    The first step in getting approval for the exchange is to “cleanup” the appropriations and water rights on its ranch on the Encampment River. Sinclair has proposed a number of cleanup petitions to the Board of Control in its attempt to bring the recorded appropriations it wants to exchange into conformity with the way the water has been used for irrigation. The petitions include some incorrect assertions or misleading maps that do not correctly identify present uses and legal status of appropriations and the use of water on the ground by Sinclair or its predecessors or other nearby appropriators.

    Sinclair maintains they can exchange the water rights because the same entity owns the water rights of both the ranch and the refinery, and therefore no determination needs to be made of whether change of use of the water from agricultural to industrial usage will be permitted. An exchange of its water rights and water in any year would “dry up” the Sinclair ranch for an entire growing season. It is unclear how that process would be accomplished without changes or increased regulation of the appropriations and administration of downstream users, such as our ranch, who continue to share and use common diversions and ditches.

    The Wyoming statute (41-3-106) that authorizes exchanges of appropriated water rights provides in part that such an exchange shall not be approved by the State Engineer if (i) the exchange would adversely affect other appropriators, (ii) would be too difficult to administer (i.e. enforce), or (iii) would be adverse to the public interest. It should also be noted that the filing and approval of such a transfer petition does not provide any opportunity for notice to affected landowners, public review or comment. We question whether Sinclair can fully satisfy these requirements under its present petitions before the BOC and the State Engineer.

    Regardless of whether these water decisions are driven by climate change or normal cycles of dry years, nothing in Wyoming water law was adopted to deal with climate change in so far as we are aware. Climate change, short or long term, can have significant effect on all sources of water in the state; to use provisions of water law not intended to address climate change-induced drying of the land and administered pretty much in the dark by non-elected administrators is a significant risk and should be a concern for most in agriculture who use State water for irrigation. It is not in the public interest to do so.

  2. The types of exchanges should only be allowed where the State Engineer determines to enter into a water supply agreement from reservoir storage on the condition that water use on the lands subject to the historic water rights are curtailed in years where there has been abundant snow pack.