Could Wyoming's State Engineer be required during the May–September irrigation season to shut off junior upstream Wyoming irrigators so the Bureau of Reclamation could fill Pathfinder Reservoir?
Plain-English summary
Pathfinder Reservoir on the North Platte River fills under a 1904 Wyoming water right with a capacity of about 1.07 million acre-feet. As part of negotiations to address Platte River endangered species issues, the Bureau of Reclamation proposed restoring 53,493 acre-feet of storage that had been lost to sedimentation. Upstream Wyoming ranchers worried that a bigger Pathfinder would mean more demand for water, and that during the irrigation season (May 1 through September 30) the Bureau might "call" the river under its senior 1904 priority and force junior upstream headgates to close so Pathfinder could fill.
Governor Freudenthal asked the AG whether the State Engineer should honor that kind of irrigation-season call. AG Patrick Crank's short answer was no, and the analysis ran on two tracks.
On the federal track, the U.S. Supreme Court's modified decree in Nebraska v. Wyoming (2001) capped Wyoming irrigation at 226,000 acres and 1.28 million acre-feet of consumptive use above Pathfinder, with another cap below. Reading those caps as the floor and then layering on a priority-based irrigation-season call would have created a third restriction that swallowed the first two. The 1945 and 2001 decisions repeatedly emphasized that "strict adherence to the priority rule may not be possible" when apportioning interstate water. The decree expressly contemplated an automatic call for the federal reservoirs only between February and April when forecasted supply was low; it did not impose an interstate priority system in irrigation season.
On the Wyoming track, the AG read the state Constitution and the State Engineer's statutes to require flexible administration that minimized interference between storage rights and direct-flow rights. Wyo. Stat. Ann. § 41-3-504 authorized superintendents to make regulations securing the "equal and fair distribution of water." Wyo. Stat. Ann. § 41-3-603(a) authorized water commissioners to require the filling of any reservoir whenever practical and water was available. The Board of Control's regulations told reservoirs to fill at times of "least interference" with direct-flow appropriators. Honoring an irrigation-season call would have closed hundreds of small upstream headgates for the diffuse benefit of one downstream reservoir, in tension with all three of these instruments.
The AG also reasoned that Pathfinder fills during the off-season starting in October, that upstream junior direct-flow rights generate return flows, and that an irrigation-season call would put Wyoming appropriators in a worse position than their Colorado neighbors, who had been allowed to make out-of-priority diversions junior to Pathfinder.
Currency note
This opinion was issued in 2004. Subsequent statutory amendments, court decisions, or later AG opinions may have changed the analysis. Treat this page as historical context, not current legal advice. Verify current law before relying on any specific rule, deadline, or remedy mentioned here.
Background and statutory framework
Pathfinder Reservoir is owned and operated by the U.S. Bureau of Reclamation as part of the North Platte Project. Its 1.07 million acre-foot capacity is appropriated under a 1904 Wyoming priority. The Pathfinder Modification Project (PMP) restored about 53,493 acre-feet of capacity lost to sedimentation, with about 33,493 acre-feet earmarked for endangered-species recovery and 20,000 acre-feet for Wyoming uses. The PMP storage space itself was not at issue: the Nebraska v. Wyoming settlement stipulation expressly prohibited the Bureau from calling for regulation of upstream junior rights to fill that restored space.
The interstate background was the long-running U.S. Supreme Court litigation between Nebraska, Wyoming, and Colorado, decided in 1945 and revisited in 1953, 1993, 1995, and 2001. The 2001 modified decree limited Wyoming's irrigation above Guernsey Reservoir to a fixed acreage and a fixed consumptive use, with separate caps for the segment between Pathfinder and Guernsey. The decree also provided for an automatic call on the mainstem federal reservoirs in Wyoming when forecasted supply was below 1.1 million acre-feet, but expressly only between February and April.
Wyoming law allocated water under prior appropriation but tempered it: the Constitution at art. I, § 31 declared that water "control must be in the state, which, in providing for its use, shall equally guard all the various interests involved." The State Board of Control's rules at the time provided that reservoirs "be filled at times that will not interfere with or that will provide the least interference with the use of water by direct flow appropriators."
Common questions
Q: What was a "call for regulation" in Wyoming water law?
A: When a downstream senior water right was not getting its full appropriation, the holder could ask the State Engineer to "call" the river, meaning to shut off junior upstream rights until enough water reached the senior. Direct-flow calls were common; reservoir calls demanded the entire flow until the reservoir was full.
Q: Why did Wyoming AG Crank conclude that an irrigation-season Pathfinder call would not be honored?
A: Three reasons: (1) the U.S. Supreme Court's caps on acreage and consumptive use already defined Wyoming's interstate obligation, and adding a priority-based irrigation-season call would have made those caps largely beside the point; (2) Wyoming statutes and Board of Control rules told the State Engineer to fill reservoirs in ways that least interfered with direct-flow rights; (3) Pathfinder already had several months from October through April to store under its priority before irrigators relied on the river.
Q: What did the 2001 modified decree actually require for federal reservoir calls?
A: The decree provided for an automatic call on the mainstem federal Wyoming reservoirs when forecasted water supply was less than 1.1 million acre-feet, and that automatic call ran from February through April only. After May 1, the equitable apportionment kicked in and Pathfinder continued to fill in priority with the other federal reservoirs but without a request for regulation against upstream Wyoming juniors.
Q: Did the opinion say Wyoming's priority system was abandoned for Pathfinder?
A: No. It said Wyoming's priority system was alive and well in intra-state administration, but that strict priority was not the sole rule for interstate apportionment, and that the State Engineer had discretion under Wyoming law to consider equality, fairness, prevention of waste, and timing when filling reservoirs.
Q: How did upstream junior rights and downstream senior reservoirs differ in their effect on the river?
A: Direct-flow rights had to divert during irrigation season or get nothing, and they typically returned a portion of diverted water back to the stream. A reservoir call demanded the whole river until full and gave no allowance for those return flows. The AG used that asymmetry to support a "least interference" result.
Q: What was the practical interest at stake for Wyoming ranchers?
A: Upper North Platte basin ranchers feared that any expansion of Pathfinder demand would translate into shut-off orders during their irrigation season, threatening the small, numerous tributary rights identified by the 1945 Supreme Court as a critical part of the regional economy.
Citations and references
Wyoming statutes and constitutional provisions:
- Wyo. Const. art. I, § 31
- Wyo. Stat. Ann. § 41-3-504
- Wyo. Stat. Ann. § 41-3-603(a)
Federal cases:
- Nebraska v. Wyoming, 65 S. Ct. 1332 (1945)
- Nebraska v. Wyoming, 122 S. Ct. 420 (2001)
Other authorities:
- 2001 Nebraska v. Wyoming Final Settlement Stipulation, Appendices E and F
- Wyoming State Board of Control Regulations and Instructions, Chapter 1, § 7
Source
- Landing page: https://ag.wyo.gov/formal-opinions
- Original PDF: https://drive.google.com/file/d/0B-uookG6TajHczJFX3lRcmlQcjQ/view?resourcekey=0-v9U0iAA48nNFcdZ7viZ2fw
Original opinion text
Governor
Dave Freudenthal
Administration
123 State Capitol
Cheyenne, Wyoming 82002
307-777-7841 Telephone
307-777-6869 Fax
Attorney General
Patrick J. Crank
Chief Deputy Attorney General
Elizabeth C. Gagen
FORMAL OPINION NO. 2004-001
August 31, 2004
The Honorable Dave Freudenthal
Governor, State of Wyoming
Capitol Building
Cheyenne, Wyoming 82002
Re: Request for opinion evaluating the legal basis for administering a call for regulation to fill Pathfinder Reservoir during the irrigation season
Dear Governor Freudenthal:
For several years, Wyoming, Nebraska, Colorado, the United States Department of the Interior, and representatives of water users and conservation organizations have been negotiating options to address endangered species issues on the Platte River. One proposal being considered is restoration of storage capacity in Pathfinder Reservoir. The proposal is to restore 53,493 acre feet of storage space lost to sedimentation, with 33,493 acre feet of the restored capacity allocated to endangered species recovery uses and 20,000 acre feet allocated to Wyoming uses.
Wyoming ranches above Pathfinder typically have a mixture of direct flow irrigation rights both junior and senior to the Pathfinder priority date. Upper North Platte basin water users have expressed concerns that the restoration of storage capacity creates an increased demand for water from the upper North Platte River basin that will increase their exposure to calls for regulation. In particular, the appropriators are concerned with regulation during the irrigation season from May 1 through September 30 and the impact regulation could have on the region's economy. You have requested that this office issue an opinion evaluating the legal basis for administering a call for regulation to fill Pathfinder Reservoir during the irrigation season.
Question Presented: Should the State Engineer allow water to be stored in Pathfinder Reservoir under a priority call between May 1 and September 30 each year?
Short Answer: No. Please see discussion.
DISCUSSION
The United States Bureau of Reclamation owns and operates Pathfinder Reservoir as part of the North Platte Project. Pathfinder Reservoir is filled under a 1904 Wyoming appropriation, is administered under state law and has an adjudicated capacity of 1,070,000 acre-feet. The Pathfinder Modification Project (PMP) will recapture 53,493 acre-feet of the capacity lost to sedimentation. The PMP storage space is not the focus of this opinion because the Nebraska v. Wyoming settlement stipulation clearly provides that the Bureau may not call for regulation of upstream junior rights (with the exception of those rights pertaining to Seminoe Reservoir) to fill this restored space. Final Settlement Stipulation, Appendix F, p. 110.
The question this opinion addresses is whether the State Engineer should honor a Bureau of Reclamation "call" or request for regulation during the irrigation season for the 1904 priority storage right in Pathfinder Reservoir. Two sources of law govern appropriations from the North Platte River, including appropriations to fill reservoirs. One source is the United States Supreme Court decisions and court-approved settlement stipulation in the multi-state North Platte River litigation. The other is Wyoming state law. Neither source supports approving an irrigation season call for regulation to benefit Pathfinder Reservoir.
Nebraska v. Wyoming
The Supreme Court's Modified Decree in Nebraska v. Wyoming, 122 S. Ct. 420 (2001) contains no provision requiring the State Engineer to honor a priority call to store water in Pathfinder during the irrigation season. To the contrary, it contains provisions that are inconsistent with honoring a priority call for Pathfinder.
The Modified Decree places two limits on Wyoming's water use from the North Platte River and its tributaries above Guernsey Reservoir. Total intentionally irrigated acreage may not exceed 226,000 acres, and consumptive use for irrigation may not exceed 1,280,000 acre feet above Pathfinder and 890,000 acre feet between Pathfinder and Guernsey, using a ten-year rolling average. The inclusion of a consumptive use cap necessarily implies that Wyoming irrigators will have the opportunity to irrigate enough acres over enough time to consume that much water. To read in a new requirement that Wyoming honor a post-May 1 Pathfinder call and deny irrigation water to any land with a priority date junior to Pathfinder's is a third restriction that swallows the other two.
The history of the North Platte River litigation confirms the U.S. Supreme Court's conscious decision to impose limitations on interstate operations other than strictly a priority system. In each round of litigation, Nebraska tried, without success, to have the Supreme Court impose an interstate priority system. In 1945, the Supreme Court considered the priority system in apportioning the river equitably, but imposed instead, among other limitations, an acreage limit (then 168,000 acres) for irrigation for the upper North Platte River basin and the mainstem between Pathfinder and Guernsey Reservoirs in Wyoming. The Supreme Court recognized that the priority system is important but should not be the sole factor in apportioning the interstate demands on the river:
[I]f an allocation between appropriation States is to be just and equitable, strict adherence to the priority rule may not be possible. For example, the economy of a region may have been established on the basis of junior appropriations. So far as possible those established uses should be protected though strict application of the priority rule might jeopardize them.
Apportionment calls for the exercise of an informed judgment on a consideration of many factors. Priority of appropriation is the guiding principle. But physical and climatic conditions, the consumptive use of water in the several sections of the river, the character and rate of return flows, the extent of established uses, the availability of storage water, the practical effect of wasteful uses on downstream areas, the damage to upstream areas as compared to the benefits to downstream areas if a limitation is imposed on the former, these are all relevant factors. They are merely an illustrative not an exhaustive catalogue. They indicate the nature of the problem of apportionment and the delicate adjustment of interests which must be made.
Nebraska v. Wyoming, 65 S. Ct. 1332, 1351 (1945).
The Supreme Court revisited Nebraska v. Wyoming in 1953, 1993, 1995, and 2001. The 2001 Modified Decree expanded the limitation on irrigation in Wyoming to include both consumptive use and irrigated acreage above Guernsey Reservoir. The Modified Decree added a consumptive use cap for irrigation purposes above Guernsey Reservoir (except Casper/Alcova Irrigation District) and expanded the 1945 Decree's limitation on irrigated acreage above Guernsey Reservoir (with the same exception) to include tributaries between Pathfinder and Guernsey Reservoirs. The Court remained consistent in support of the historic sectionalized administration of the river, where available flows have been equitably apportioned between the states with certain specified limitations on acreage, consumptive use, and reservoir storage. The 2001 Modified Decree and related settlement stipulations also provided for an automatic priority call for the mainstem federal North Platte River reservoirs in Wyoming when forecasted water supplies are less than 1.1 million acre feet. The State Engineer would honor this call, whenever conditions warrant, from February through April. The Court did not, however, in 2001, or at any other time during the North Platte River litigation, impose an interstate priority system. Nothing in the Final Settlement Stipulation or in the history of the Modified Decree requires Wyoming administrators to honor a Pathfinder request for regulation between May 1 and September 30.
Wyoming Law
Having concluded that nothing in the Modified Decree requires the State Engineer to honor a post May 1 request for regulation to fill Pathfinder Reservoir, the next question is whether Wyoming law requires the State Engineer to honor such a request. The U.S. Supreme Court left priority administration within Wyoming to be controlled by Wyoming law. Nebraska v. Wyoming, 122 S. Ct. at 427. Wyoming law allows flexible administration in allocating stream flow between storage and direct flow rights and authorizes the State Engineer to consider a number of factors in regulating the filling of reservoirs. A review of these factors compels the conclusion that the State Engineer should not honor a priority call for storage in Pathfinder during the irrigation season.
Direct flow rights and reservoir rights have different needs in the timing of their diversions, and they have different effects upon a stream and other water users. Direct flow appropriators must divert during the irrigation season or gain no benefit from their appropriations, while a storage right can accrue storage at any time of the year and hold the accumulated water for later release. Direct flow rights usually have return flows, which are available for downstream appropriators. In some circumstances, upstream junior rights may create enough return flows to satisfy senior downstream rights. A satisfied senior right has no basis to request a priority call. But when a downstream reservoir makes a call, it demands the whole river until it is full, with no allowance for return flows from upstream junior appropriators. All upstream junior headgates could be closed until the reservoir is full.
The Wyoming Constitution contemplates balancing these diverse demands upon Wyoming rivers. It provides:
Water being essential to industrial prosperity, of limited amount, and easy of diversion from natural channels, its control must be in the state, which, in providing for its use, shall equally guard all the various interests involved.
WYO. CONST. ART. I, § 31.
This balancing of interests is reflected in Wyoming statutes which attempt to minimize interference between storage and direct flow appropriations. Wyoming statutes authorize the State Engineer and his superintendents and commissioners to base priority regulation decisions, including the filling of reservoirs, on equality and fairness in the distribution of water, prevention of waste and timing of water availability. See WYO. STAT. ANN. § 41-3-504 (authorizing each division superintendent to "make such other regulations to secure the equal and fair distribution of water in accordance with the rights of priority of appropriation"); WYO. STAT. ANN. § 41-3-603(a) (authorizing each water commissioner to "require the filling of any reservoir whenever practical and whenever water is available for storage from the stream from which the appropriation is established.").
Wyoming's State Board of Control, consisting of the State Engineer and the four Water Division Superintendents, has further implemented this policy of minimizing the competition between storage rights and direct flow rights. Chapter 1, Section 7(b) of the Board's rules provides, in part:
In order to conserve the waters of the state, it is a necessary requirement that all reservoirs be filled at times that will not interfere with or that will provide the least interference with the use of water by direct flow appropriators and thereby prevent a waste of water.
STATE BOARD OF CONTROL, REGULATIONS AND INSTRUCTIONS, CHAPTER 1 § 7.
Based on the foregoing constitutional, statutory and regulatory requirements, the State Engineer and his superintendents and commissioners should require the filling of Pathfinder Reservoir when it will interfere least with direct flow rights. In determining whether to honor a post May 1 call for regulation for Pathfinder, the State Engineer and his staff may consider whether a call for regulation is futile, as well as whether the benefit of honoring an irrigation season call is inconsistent with the equitable apportionment in the Modified Decree, or is a waste of water. Based on a weighing of these factors the State Engineer should not honor a request for priority regulation during the irrigation season to fill Pathfinder Reservoir.
First, Pathfinder Reservoir stores water during the off-season, beginning in October or earlier. The 2001 Final Settlement Stipulation, Appendix E (1998 stipulation relating to the allocation of water during periods of shortage) and the NPDC Charter Exhibit 5 recognize this in their provision for an automatic call. The NPDC Charter Exhibit 5 provides for an automatic call for Pathfinder when an allocation year is anticipated. An allocation year is one in which, according to agreed-upon formulas, there may not be enough water stored in Pathfinder Reservoir, Guernsey Reservoir, and the Inland Lakes, plus anticipated runoff, to meet a 1.1 million acre-foot irrigation demand. The allocation year automatic call expires May 1st, when the decree-specified irrigation season of May 1st through September 30th begins. (Final Settlement Stipulation, Appendix E). It is also on May 1st, after Pathfinder Reservoir has had several months to store water in priority, that Wyoming is entitled to its equitable apportionment of water under the Modified Decree. However, Pathfinder Reservoir is continued to allow to store from the available water supply, in priority with respect to the other federal reservoirs governed by the Decree, without benefit of a request for regulation.
Second, as the U.S. Supreme Court explained in its 1945 decision, regulating the upstream junior direct flow rights will have a small cumulative positive effect downstream in proportion to the economic dislocation on dozens of small ranches:
As we have noted, most of the land under irrigation in the section above Pathfinder is irrigated from tributaries. The rights are small but very numerous. The total acreage under irrigation is 153,000 acres, allowing for a margin of error. So far as the tributaries above Pathfinder are concerned, practical difficulties of applying restrictions which would reduce the amount of water used by the hundreds of small irrigators would seem to outweigh any slight benefit which senior appropriators might obtain. This does not seem to be denied.
Nebraska v. Wyoming, 65 S. Ct. at 1353.
Third, the upper North Platte basin appropriators are already subject to consumptive use and irrigated acreage limitations. To impose a third priority-based restriction between the direct flow and storage rights would not only impose a restriction that swallows the other restrictions, it would also leave Wyoming appropriators in a worse position than their neighbors upstream in Colorado. As the Supreme Court observed:
Appropriators in Colorado junior to Pathfinder have made out-of-priority diversions of substantial amounts. Strict application of the priority rule might well result in placing a limitation on Colorado's present use for the benefit of Pathfinder. But as we have said, priority of appropriation, while the guiding principle for an apportionment, is not a hard and fast rule. Colorado's countervailing equities indicate it should not be strictly adhered to in this situation.
Nebraska v. Wyoming, 65 S. Ct. at 1351.
CONCLUSION
The State Engineer should not honor a request for priority regulation for Pathfinder during the irrigation season. Neither the U.S. Supreme Court cases nor Wyoming law requires strict conformity to the priority system between storage and direct flow rights. Refusing to honor such a request properly minimizes interference between direct flow and storage rights and is consistent with decades of state water policy.
Patrick J. Crank
Attorney General