{"id":30107,"date":"2026-08-01T07:55:23","date_gmt":"2026-08-01T11:55:23","guid":{"rendered":"https:\/\/www.ecoportal.net\/en\/?p=30107"},"modified":"2026-08-01T07:55:23","modified_gmt":"2026-08-01T11:55:23","slug":"arizona-cools-river-to-save-native-fish","status":"publish","type":"post","link":"https:\/\/www.ecoportal.net\/en\/arizona-cools-river-to-save-native-fish\/30107\/","title":{"rendered":"Officials in Arizona cooled a river to stop an invasive species from breeding and save the humpback chub, but the hydroelectric plant paid the price"},"content":{"rendered":"

A serious multiyear drought resulted in extremely low water levels<\/strong> behind Glen Canyon Dam in Northern Arizona. Lower lake elevation behind the dam allowed larger increases in river temperatures during warm summer months.<\/p>\n

Higher water temperatures enabled the invasive predators (predatory fish) to move downriver past the dam openings.<\/p>\n

As these non-native predators moved downstream, they started to endanger many different species<\/strong> of native fish.<\/p>\n

How did saving endangered native fish force a dramatic operational shift at Glen Canyon Dam?<\/p>\n

Protecting native species in the Colorado River<\/h2>\n

The Grand Canyon ecosystem depends on a delicate balance<\/strong> supporting certain native fish species. Their populations are currently being harmed due to their requirement for cold, natural river habitat.<\/span><\/p>\n

Before severe drought, Glen Canyon Dam consistently released cold water from Lake Powell every month.<\/p>\n

However, because of extreme drought conditions, Lake Powell dropped so low that it reached dangerous levels<\/strong>.<\/p>\n

Hotter water, warmed by direct sunlight, began flowing through the dam’s main electrical generating pipes. Warmer water provided the perfect environment for invasive smallmouth bass and green sunfish to migrate and spawn.<\/span><\/p>\n

Smallmouth bass are aggressive warm-water predators that consume large amounts of young humpback chubs<\/strong>.<\/p>\n

Biologists stated that expanding smallmouth bass populations into other parts of the system will have devastating effects.<\/p>\n

It will affect all of the native fish<\/strong> populations throughout the whole Grand Canyon River system. Federal agencies worked cooperatively with tribal governments, state wildlife organizations, and National Park researchers.<\/p>\n

Engineering a cool water release below the dam<\/h2>\n

To stop invasive smallmouth bass, the Bureau of Reclamation<\/a> devised a unique cool-water release plan. Teams continuously monitor river temperatures at various points below Glen Canyon Dam.<\/p>\n

When river temperatures downstream exceed important biological limits, operators initiate specific cool water flows<\/strong>.<\/p>\n

As highlighted by the Society of Environmental Journalists<\/a>, monitoring these releases allows operators to disrupt bass reproduction.<\/p>\n

Operators draw cooler water from the warmer upper layer of Lake Powell to lower river temperatures. By doing this, engineers keep the river cool enough<\/strong> for native fish species to survive.<\/p>\n

They disrupt smallmouth bass reproduction cycles throughout the entire Grand Canyon River corridor.<\/p>\n

The financial and operational cost to hydropower<\/h2>\n

Although protecting native fish species was successful, engineering changes to operate Glen Canyon Dam were also expensive<\/strong>. What was the effect on electrical power generated by the hydroelectric dam when engineers cooled the river?<\/span><\/p>\n

Engineers were forced to open four additional low-level river outlet bypass tubes to gain access to colder water. This colder water was deep within Lake Powell.<\/span><\/p>\n

Vast quantities of water were routed through bypass tubes instead of passing<\/strong> directly through primary electric-generating pipes.<\/p>\n

Routing water through those bypasses meant zero electricity could be generated for regional use.<\/p>\n

Consequently, engineers experienced significant reductions in hydropower generation capability. That drop in power generation choked off the electricity sales needed to fund critical regional infrastructure improvements<\/a>.<\/span><\/p>\n

Regional public-power utilities incurred high costs purchasing supplemental fossil-fuel-based power.<\/p>\n

Millions of dollars in clean-energy production were lost<\/strong> each week while engineers bypassed generators producing electricity.<\/p>\n

Balancing ecological protection and energy demands<\/h3>\n

Engineers continue to modify their flow scheduling plans to reduce economic losses<\/a> from future seasonal releases. Use of better real-time data allows engineers to produce fewer bypasses while providing adequate cooling to preserve endangered species.<\/p>\n

Balancing native fish preservation goals with<\/strong> the production of clean energy is always necessary.<\/p>\n

A sustainable compromise must be found for both fragile river ecosystems and regional energy systems.<\/p>\n

Without swift intervention, these resilient invasive predators threaten to unravel decades of careful conservation work<\/strong> in a single season. As grid managers look for ways to safeguard power supplies and river health, balancing these competing demands is critical.<\/p>\n

The same challenge appears in other systems where engineers must carefully regulate the movement of energy and resources<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

A serious multiyear drought resulted in extremely low water levels behind Glen Canyon Dam in Northern Arizona. Lower lake elevation behind the dam allowed larger increases in river temperatures during warm summer months. Higher water temperatures enabled the invasive predators (predatory fish) to move downriver past the dam openings. As these non-native predators moved downstream, … Read more<\/a><\/p>\n","protected":false},"author":27,"featured_media":30142,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"river,temperature,management","rank_math_title":"","rank_math_description":"Glen Canyon Dam cooled the Colorado River to stop invasive smallmouth bass breeding, but the effort reduced hydropower generation across the region.","footnotes":""},"categories":[8],"tags":[],"class_list":["post-30107","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-energy"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/30107","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/users\/27"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/comments?post=30107"}],"version-history":[{"count":0,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/30107\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/30142"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=30107"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=30107"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=30107"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}