Challenges in Balancing Hydropower and Ecosystem on the Colorado River

The Colorado River is under significant strain as decreasing water levels and climate change impact its reservoirs. This has led to complex decisions for officials, where conservation efforts and electricity costs clash.

The issue involves the threatened humpback chub, a fish native to the river. To protect it from predators, officials consider a ‘cool mix flow’ at the Glen Canyon Dam in northern Arizona. This involves releasing cold water from deep reservoirs, but results in power generation loss since hydropower turbines aren’t in these cooler sections.

This proposal follows the worst snowpack recorded for the Colorado River Basin, which serves multiple stakeholders, including farmers, industries, and 40 million people in seven U.S. states, tribal nations, and Mexico. As these states struggle to reach a consensus on water sharing post this year, after the guidelines expire, the urgency for solutions grows.

There is a limited water supply. It’s getting even lower. And with that, a lot of hard decisions need to be made, John Berggren, regional policy manager for Western Resource Advocates, emphasized the pressing nature of these decisions.

For utilities dependent on this hydropower, the alternative cooling method would mean increased costs. They’d need to purchase alternative energy, imposing a financial burden on customers. However, proponents argue that without these cool releases, warmer downstream waters will enable non-native predatory fish to spawn. This threat looms over the humpback chub and a nearby renowned trout fishery.

The Bureau of Reclamation plans to announce a decision soon, weighing ecological health against hydropower production. If approved, the cool water releases would bypass turbines through jet tubes from June to October.

How Cool Water Helps

Lake Powell, a key reservoir, is only 23% full after years of overuse and evaporation driven by rising temperatures. With a record-low inflow expected, surface water—already warm—flows through generators downstream.

Introduced for sport fishing in the 1980s, smallmouth bass thrive in the warm surface waters of Lake Powell and find their way downstream. This creates complications for the humpback chub and other protected fish in the Grand Canyon. Many bass survive the generators, and if the waters are warm enough, they spawn.

While millions are spent annually to manage these predators in the river’s upper sections, cooler sections have provided refuge until now. Alarmingly, in 2022, unprecedented warm temperatures downstream allowed smallmouth bass to appear near the dam.

Officials predict water temperatures will rise past 60 degrees Fahrenheit near the dam by mid-June, challenging native fish populations. Past cool releases in 2024 and 2025 thwarted spawning.

Heather Whitlaw from the U.S. Fish and Wildlife Service highlighted the importance of maintaining cooler water. We are certainly just giving up on the future for any kind of recovery for humpback chub and all of the other pieces of the system that rely on those cooler water temperatures, Whitlaw noted.

Without a viable long-term solution, the reliance on manual removal of predatory fish remains. Yet, this approach risks further hydropower loss, prompting concerns from utilities reliant on federal generators.

Economic Impacts of Reduced Hydropower

If the cool water release is approved, bypassing turbines might cut hydropower at Glen Canyon Dam by half. This scenario concerns utilities like Heber Light & Power in Utah, which would face increased costs when purchasing energy elsewhere.

The Colorado River Energy Distributors Association, representing 155 federal hydropower users, expressed unease over this proposal. In a letter to Interior Secretary Doug Burgum, they questioned the sustainability of such releases and their impact on critical funds supporting hydropower operations.

During the 2024 releases, nearly 900,000 acre-feet of water bypassed the generators, leading to $19 million in energy replacement costs. This year, replacement is estimated to cost $25 million.

Heber Light & Power’s Emily Brandt acknowledges ecological balances but questions the utility of the cool mix approach. Ongoing drought already diminishes power generation.

Increased financial pressures contribute to residential rate hikes. Customers, including Ann Moulton from Heber City, report rising electricity bills, straining budgets. Delayed payments have jumped from 10% to 12% recently.

Brandt said, We’re already seeing reduced generation from drought, and now we’re seeing even further reduced generation because of this environmental experiment.

Impact on Fisheries

Fisheries downstream face an uncertain future. Dave Foster recalls the 2022 trout die-off in Marble Canyon, where warm waters destroyed half of the rainbow trout population. Despite efforts to counteract this loss, recovery remains slow.

Foster advises customers against booking trips post-mid-June if the water temperature exceeds safe levels for fish. Without the cool water releases this year, that’s it for the trout fishery. It will destroy it, Foster warned.

This situation, complicated by ecological and economic factors, underscores the need for timely decisions to preserve the ecosystem and supply necessary resources. The ongoing tension between hydropower interests and environmental conservation reflects a broader challenge in resource management along the Colorado River.