Municipal water is among the most vulnerable in the Colorado River Crisis

When the Cheyenne City Water Authority approved a contract in October to supply up to 14,500 acre-feet of water over 15 years for a proposed gold mine west of the city, attorneys insisted on including a clause in the contract. It reserves the right to cut water deliveries if the city itself is forced to limit its water use due to the Colorado River crisis.

“Most of our water comes from the Colorado River [basin] and if that calls [requiring upstream users to cut consumption] comes in, we’re in big trouble,” said Cheyenne Mayor Patrick Collins.

About 70% of the city’s municipal water supply originates 150 miles west of the Little Snake River drainage basin, part of the Colorado River Basin. A complex “cross-basin” system of pumps, tunnels and pipelines transports water to the city under the continental divide in Medicine Bow Routt National Forest.

Cheyenne’s legal claims to the water of the Colorado River Basin were appropriated from 1954 to 1982 – making it a relatively new user in the system. If there is a cut, it would be applied to the most recent or “recent” funds and then worked back to the 1922 Colorado River Compact. That means depending on how far back in time a cut goes, 70% of the city’s water supply could be shut off — a move that could happen as early as 2028 if hydrological conditions continue to deteriorate, according to the Wyoming State Engineer’s office.

This map shows Cheyenne’s municipal water supply system, which feeds water from the Little Snake River Basin. (Cheyenne Board of Public Utilities)

“If we lose 100% of our water from the Colorado River Compact, we’re upside down,” Collins said, adding that about 80,000 people depend on the city’s municipal water system. “We would not have enough water to meet our current needs.”

Right now, Cheyenne, Baggs, Rock Springs, Green River, Pinedale and a handful of other cities that depend on water from Wyoming’s Little Snake and Green River basins are looking at where they stand in the pecking order of appropriated water rights in the event of a cut . Although communities under the Colorado River Compact and associated statutes account for a small percentage of water users in Wyoming, their legal entitlements to the water are among the most vulnerable.

First in time, first in law

If the Upper Colorado River Basin Commission enacted a cut for Wyoming, it wouldn’t necessarily force all water users subject to the pact to shut down their taps entirely.

In terms of usage, there is no cut priority – be it irrigating cattle and alfalfa fields, cooling water used at the Jim Bridger coal-fired power plant, or water being piped to homes for domestic use. Instead, a cut would be applied based on the water appropriation’s first-in-time, first-in-right doctrine: those receiving their water appropriation no later than on time would be the first to be asked to turn off their water.

For example, if the state needed to cut 100,000 acre-feet of water—roughly one-sixth of its annual water use in the Colorado River Basin—the state engineer would start with the latest means and work back in time until the 100,000-acre-foot consumptive water-use limit was met.

Shauna Gray and her dog Lula Mae paddling at Rob Roy Reservoir on July 31, 2022. The reservoir is part of a cross-basin water system that supplies Cheyenne with water. (Dustin Bleizeffer/WyoFile)

If that required, say, shutting down all water allocations in the Colorado River Basin by 1970, it would stall all water that has been appropriated since then — whether for industrial, municipal, or agricultural uses. The cities of Rock Springs and Green River, which share a municipal water system serving approximately 39,000 residents, would lose access to 75% of their water appropriation through Green River. Cities would continue to be allowed to use the 4,343 acres-per-year appropriation they had secured in 1928 and the 2,895 acres-per-year appropriation that occurred prior to the 1922 Pact. The remainder – 75% – was appropriated in 1971 and thereafter.

This type of variable vulnerability affects many Colorado River Basin water users with appropriated rights acquired at different times. The exact order in which a cut would be applied is well documented and under constant review, according to the state engineering firm.

Small straw, big weak point

Agriculture accounts for 83.7% of Wyoming’s water use in the Colorado River system, according to SEO. Municipal water use accounts for about 2.8% — or 3.3% if you include rural domestic water use. Industry — Trona plants, coal-fired power plants, oil and natural gas processing — accounts for most of the remaining 13%.

Approximately 70% of Wyoming agricultural irrigation water rights were appropriated before 1922. These pre-1922 appropriations are not subject to the Colorado River Compact and cannot be cut off by a cut. The 1922 protection applies to all water users of the Colorado River Basin.

However, much of the water allocations in the Colorado River Basin held by Wyoming municipal water boards date from after 1922. This means that approximately 125,000 Wyoming residents and businesses are affected by a cut.

“If we lose 100% of our water from the Colorado River Compact, we will be upside down. We would not have enough water to meet our current needs.”

Cheyenne Mayor Patrick Collins

Faced with the cut clause in Cheyenne’s water contract, gold mine developer Gold King Corp. according to Mayor Collins for alternative water resources. The city of Cheyenne — as well as Green River, Rock Springs, and others — are doing the same.

“There’s a chance we wouldn’t be able to collect water from the Little Snake System if this were the case [a] Cut call goes under 1954,” Cheyenne Board of Public Utilities Administrator Brad Brooks told WyoFile. “We are looking at additional water to mitigate this possibility and are planning for the worst case scenario that our Little Snake water becomes unavailable.”

Green River and Rock Springs are in the same boat. Their shared municipal water system collects 100% of its water from the Green River and its tributaries to serve approximately 39,000 residents in and around the two cities. Only 10% of their water appropriations in the Colorado River Basin predate the 1922 Pact.

Green River. (Google Earth)

Although cities are not relying on the full volume of their legal entitlements to water from the Colorado River Basin, now is the time to plan for additional water sources. 2028, the year Wyoming may see its first cut, is not far off, said Bryan Seppie, general manager of the Green River/Rock Springs Joint Powers Board.

“Understand, [a curtailment] probably not a year-long event,” Seppie told WyoFile, adding that a lot depends on what Mother Nature has in store. “We need to secure other water resources to serve as backup water when [a curtailment] should happen. Conservation is a tool, but with these kinds of cuts, conservation won’t turn you away.”

backup water

A portion of the Gold King deal provides Cheyenne’s Board of Public Utilities with approximately $5 million in fees that would help meet the cost of expanding Cheyenne’s groundwater capacity. The city’s water board is also seeking grants of up to $10.5 million from the Wyoming Water Development Commission for its Borie Wellfield Extension project. According to the board, the expansion would add approximately 3,300 acre-feet of water per year to the city’s water portfolio.

That would increase Cheyenne’s water source portfolio outside of the Colorado River Compact to 9,900 acres per year. But the city would still be in trouble if it were cut, as its average annual use is about 14,000 acre-feet.

“We are actively exploring opportunities” for additional water resources, said Brooks of the city’s BOPU.

Anglers try their luck on the Green River at Seedskadee National Wildlife Refuge on September 27, 2022. (Dustin Bleizeffer/WyoFile)

However, according to Seppie, expanding groundwater capacity is not an affordable option for Rock Springs and Green River. Instead, the cities are turning to those in the state with pre-1922 funds to share some water.

The federal System Conservation Program pays water users to curb consumption. Congress recently restored funding to the program, while the Inflation Reduction Act earmarks approximately $4 billion for efforts to modernize Colorado River Basin infrastructure and water management practices. Another $8.3 billion from the bipartisan infrastructure bill is available to address the United States’ water and drought problems

The SCP is an attractive option, Seppie said, for both farm irrigation contractors and municipalities. Agricultural irrigation companies that volunteer for the program can use payments to upgrade their irrigation systems to use less water.

“It’s a voluntary thing. It’s preventive and it benefits the whole system,” Seppie said. “We are not yet at a point where we are having these discussions [with city officials]. But we have a certain time frame; 2028 is not that far away anymore.”