Controversial hydroelectric project above Miracle Mile earns Wyoming water quality certificate

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Wyoming’s top environmental office has approved a “section 401” water quality certificate for Black Canyon Hydro’s controversial Seminoe pumped water storage hydroelectric project in Carbon County.

It’s the largest state-level permitting milestone for the project, which still awaits final approval from federal regulatory agencies, including the Federal Energy Regulatory Commission.

The Wyoming Department of Environmental Quality issued the certificate Thursday, underscoring its intent to, among other things, maintain the viability of the world-class Miracle Mile trout fishery. The cherished stretch of the North Platte River is immediately downstream of the Kortes and Seminoe Reservoir dams, and it’s designated as an Outstanding Resource Water.

That designation, according to DEQ, requires “no further degradation from human activity,” resulting in stringent thresholds and triggers that are “enforceable conditions of the certification” and could curb the facility’s operations if exceeded.

Though he was still reading through the 19-page certificate and 115-page “adaptive management plan,” Trout Unlimited’s Patrick Harrington said he’s generally pleased with the DEQ’s effort to solicit public comments and incorporate much of that feedback into its ongoing oversight of water quality related to the project.

“There were modest improvements, which is good,” Harrington told WyoFile on Friday. “There are still big picture things missing, like a full operational shutdown, which is something that we explicitly asked for.”

The primary water quality concerns, according to DEQ and many stakeholders involved in the process, are turbidity from daily water flushing operations and the potential to raise water temperatures — especially in the Miracle Mile. Trout are a cold-water species and particularly sensitive to warmer temperatures. Groups like Trout Unlimited and Friends of the North Platte have warned that even one day of higher-than-tolerable water temperatures could result in a devastating fish kill.

It appears the state will impose temporary operational shutdown triggers when the Miracle Mile is susceptible to high water temperatures, Harrington noted. The Miracle Mile — and nearly every river and stream in Wyoming — are particularly vulnerable to trout-killing temps when flows are low and atmospheric temperatures are higher than average.

But the state mostly relied on historic water temperature variability data from a decade ago, Harrington said, and the outlook for the Upper North Platte River system has changed significantly since then. Scientific analysis has flagged the region as particularly susceptible to a warming climate — and that’s playing out in real time this year.

Wyoming just experienced its warmest winter in modern history, and its snowpack has been beyond dismal, including for regions draining into the North Platte River and its tributaries, according to local meteorologists and water watchers. In fact, the Wyoming State Engineer’s Office in February issued a “priority administration” order restricting diversions from the North Platte River and its tributaries from Guernsey Reservoir all the way upstream beyond Pathfinder Reservoir.

The federal Bureau of Reclamation is monitoring a situation that will likely require prescribed reservoir releases this year to meet legal water delivery protocols downstream.

“Both the mountains and the lower elevations in the [North Platte River] basin have had a scarcity of precipitation,” Bureau of Reclamation spokesperson Elizabeth Smith told WyoFile on Friday. “Snowpack is well below average, and the Upper North Platte Basin is in severe drought.”

Though dire and sure to cause a lot of pain for agriculture, fishing-reliant tourism businesses and municipalities — which are first in line ordered to shut off their North Platte River spigots, the Engineer’s Office has noted — Harrington said it’s an opportunity for DEQ to collect fresh data to potentially redial some of its water quality triggers for the project.

“They do talk about recalibrating the water quality model,” he said. “If that monitoring starts sooner rather than later, maybe we will capture some of that [data] and we’ll have a little bit more confidence” in DEQ’s adaptive management plan.

The state’s certificate is proof that the project will not impose any significant environmental threats, company spokesperson Brad Carl told WyoFile.

“It confirms that the project will comply with all water quality standards and establishes robust regulatory protections to ensure that there will be no impacts to the Seminoe and Kortes reservoirs or the Miracle Mile,” Carl said.

Water battery

“Pumped water storage” involves pumping water uphill during daytime “off-peak demand” hours for electricity when wind and solar power are plentiful and wholesale electricity is cheapest. The water is released to generate hydroelectricity during higher-demand hours in the evening.

Black Canyon Hydro, a subsidiary of Utah-based rPlus Hydro, proposes building a 13,400-acre-foot reservoir in the Bennett Mountains overlooking Seminoe Reservoir near the dam — one of several reservoirs on the North Platte River.

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The massive $3 billion to $5 billion project would serve as an “energy‑storage facility,” the company told WyoFile. “Think of it as a ‘water battery’ that stores energy generated when demand is low. When demand increases, water is released from the upper reservoir back into Seminoe, driving hydroelectric turbines to produce electricity.”

Wider concerns, and assurances

In addition to criticism from national and local outdoor recreation groups, the Casper City Council joined their Natrona and Carbon county colleagues in voicing concerns over the project. In addition to potential impacts to fisheries and aquatic life, they say it threatens important elk, mule deer and sage grouse habitat, as well as a vital bighorn sheep herd — all huge revenue draws to the region.

The estimated five-year construction timeline is a particular concern for the land-based resources because the company has asked federal regulatory officials for several exemptions to seasonal construction restrictions typically imposed to protect wildlife.

For its part, rPlus Hydro said it is committed to conforming both the construction and operation of the facility to minimize impacts.

“These [DEQ water quality] protections reflect our longstanding commitment to developing energy infrastructure in a manner that respects and preserves Wyoming’s natural resources while supporting the state’s economic future,” Carl, the rPlus spokesman, told WyoFile.

Click here to learn more about FERC’s review of the project.