Three Parks, One Vital Ecosystem

Inflation Reduction Act Project Aims to Restore Ecosystem Balance within Colorado River Watershed

A northern view of Marble Canyon at the confluence of the Colorado and Little Colorado Rivers, Grand Canyon National Park.

NPS Photo

Glen Canyon National Recreation Area, Grand Canyon National Park, and Dinosaur National Monument are iconic American Southwest landscapes, attracting millions of visitors annually.

However, these park ecosystems within the Colorado River watershed are under threat. Invasive fish species are disrupting ecological balance and invasive plants have taken hold.

With the help of Bipartisan Infrastructure Law (BIL) and Inflation Reduction Act (IRA) funding, the National Park Service (NPS) is using a coordinated three-park approach to manage invasive species and continue to restore one of the country’s most vital waterways – the Colorado River, which runs approximately 1,450 miles from its source in the Rocky Mountains to its mouth in the Gulf of California in northwestern Mexico. The approach combines established scientific techniques with citizen science and state-of-the-art biological innovations.

Even in the shadowed beauty of the Grand Canyon, the fight to preserve native ecosystems is ongoing. Across the scope of this IRA project, the NPS works tirelessly to manage invasive species that threaten the balance of natural wonders like the Grand Canyon.

Freshwaters Illustrated / David Herasimtschuk

Glen Canyon National Recreation Area

Spanning 1.25 million acres in northern Arizona and southern Utah, Glen Canyon National Recreation Area is a breathtaking expanse of geological formations — red rock canyons, sandstone cliffs — and a vast reservoir formed by the Glen Canyon Dam on the Colorado River, Lake Powell.

A 15-mile stretch of the Colorado just below the dam has long been maintained as a rainbow trout fishery. Rainbow trout are an essential component of the region’s recreational fishing and local ecology. However, since 2015, brown trout, which are voracious predators, have threatened rainbow trout and other native fish populations. Park managers and scientists must figure out how to counteract the threat — and they’ve turned to anglers for help.

“The funding in 2025 and 2026 is focused on keeping an incentivized harvest program going — which is encouraging and paying people to go out and angle and to keep the brown trout they catch. Then when they turn in the heads, they get a payment,” said Emily Omana, the Grand Canyon National Park fisheries program manager. “We’ve seen population level impacts from this incentivized harvest, especially as the payments have gotten larger.”

Continuing on the incentivized harvest programs is Jeff Arnold, a National Park Service fish biologist working within this IRA project at Glen Canyon National Recreation Area. Arnold describes how this incentivized harvest program was designed to encourage public participation to help manage the highly predacious brown trout population in Glen Canyon.

“To claim any reward, anglers fill out a data card. The card, along with the brown trout head, is placed in a freezer located at the Navajo Bridge Visitor Center at Lees Ferry,” said Arnold. “It seems like the angler harvest of brown trout is directly related to the amount of reward being offered—for example, in 2022-2023, financial rewards for harvested brown trout increased to encourage more angler participation, and we saw a decline of approximately 10,500 adult brown trout in 2022 to approximately 6,400 adults in 2023.”

Moving forward, as Omana has mentioned above, funding in 2025 and 2026 is focused on keeping this incentivized harvest program going—with funds being used to sponsor tribal youth fishing trips in Glen Canyon. These trips will not only give tribal youths an opportunity to catch brown trout, but the rare chance to experience the many natural wonders at Glen Canyon, Arnold said.

“A really exciting component of this project is getting Tribal elders and Tribal youth out on fishing trips in Glen Canyon to help with this effort—an idea that was really stymied by COVID-19,” said Omana. “However, with funding available for the next few years, Tribal involvement is something Glen Canyon really wants to implement, especially in regard to incentivized harvests.”

Colorado River near Lees Ferry Site Numerous ferry accidents in the early 20th century drew attention to safety issues of the operation. This eventually led to the construction of the Navajo Bridge across Marble Canyon, completed in 1929.

NPS Photo

Threatened by brown trout, rainbow trout (pictured) fisheries at Glen Canyon National Recreation Area, as well as throughout the Colorado River system, are threatened populations. As Omana mentions, this is where they've turned to anglers for help.

NPS Photo

Grand Canyon National Park

Downriver from Glen Canyon Dam in Arizona, Grand Canyon National Park is a testament to the power and beauty of nature. As impressive as the 277-mile canyon is, the invasion of non-native smallmouth bass poses a serious threat to the park's delicate aquatic ecosystem.

Techniques such as electrofishing are being used to reduce smallmouth bass populations. However, the long-term solution lies upriver on the Colorado.

“Ongoing control efforts are aimed at controlling the spread and preventing the establishment of these high-risk fish that have entered Glen and Grand Canyons following changes in water management in the Colorado River watershed. This is due to drought, climate change, and overallocation,” Omana said. “Additional actions, however, are crucial in the fight to prevent more smallmouth bass invasions from occurring and controlling those already here”.

The Bureau of Reclamation has multiple processes to consider some of these additional actions – the Bureau recently completed a Supplemental Environmental Impact Statement and Record of Decision to use cold temperature flows to lower the water temperature in an area that is crucial for the threatened humpback chub to prevent smallmouth bass spawning—discouraging their invasion into Glen Canyon and Grand Canyon. Longer-term strategy involves managing annual water release volumes between Lake Powell and Lake Mead. Both strategies will be crucial for water delivery, agriculture, and the Grand Canyon ecosystem.

“Addressing the invasive fish problem requires more than removal efforts,” said Rebecca Koller, an NPS natural resource specialist. Public awareness and citizen involvement is needed, she said, to stop the intentional and unintentional spread of invasive fish species along the Colorado River and other waterways.

Controlling smallmouth bass is part of a larger strategy to preserve Grand Canyon National Park’s native fish species, including the threatened humpback chub, whose population has seen a significant increase thanks to conservation measures and environmental changes.

At night, a researcher carefully measures an invasive fish species, part of ongoing efforts to protect the Grand Canyon's aquatic ecosystem. Through dedicated management and conservation, the National Park Service works to restore balance in these fragile waters.

Freshwaters Illustrated / David Herasimtshuk

Controlling smallmouth bass is part of a larger strategy to preserve Grand Canyon National Park’s native fish species, including the threatened humpback chub, whose population has seen a significant increase thanks to conservation measures and environmental changes.

NPS Photo

Dinosaur National Monument

Dinosaur National Monument, straddling the border of Colorado and Utah, is a remarkable blend of ancient history and stunning natural beauty. It’s a park known for its world-class dinosaur fossil beds and the scenic Green and Yampa Rivers, tributaries of the Colorado River. Amid this grandeur, pressing issues of invasive plants like leafy spurge and Russian knapweed call for innovation in the name of eradication or suppression — either eliminating this population of these invasive plants or minimizing their impact so they are no longer harmful to ecosystems. Robert Schelly, resource stewardship and science program leader, and Emily Spencer, natural resource specialist, both at Dinosaur National Monument, are spearheading the effort.

Russian knapweed and leafy spurge cause widespread economic, agricultural, and ecological damage. Manual methods of eradication (such as physical, by-hand removal) are not always feasible or effective, so biocontrol may offer a promising solution.

“With invasive plant management, the goal is almost always eradication, but with biocontrol, the goal is not eradication anymore — it’s suppression of the invasive plant,” Spencer said. “Because it’s become so widespread and has caused some level of park-wide damage, you’re not going to, per se, put it back into Pandora’s Box anymore. So, you’re, in a way, just buying time, to guide a park or environment to a little bit more of an equilibrium.”

Biocontrol involves reuniting invasive plants with their natural predators or pathogens from their regions of origin. This approach aims to suppress, the invasive species, helping to restore balance to an ecosystem. The challenge with biocontrol is ensuring that the introduced predators are host-specific, meaning they target only the invasive plants and do not pose a threat to native or endangered species. Rigorous testing by federal agencies, such as the U.S. Department of Agriculture and the Environmental Protection Agency, is conducted to identify and approve host-specific agents. This process, which often spans decades, ensures that the biocontrol methods are safe and effective, allowing Dinosaur National Monument and other land managers to manage invasive species sustainably while preserving its natural and cultural heritage.

The scenic Yampa River can be seen here from Harpers Corners Trail, an invaluable tributary (along with the Green River) of the Colorado River system. However, within this beauty lies invasive plants that wreak havoc on these ecosystems - calling for the 'biocontrol' techniques Spencer discusses.

NPS Photo

A River of Collaboration

Funding from various sources, including the BIL and the IRA, enable hiring of scientific and technical staff, conducting surveys, and implementation of on-the-ground conservation actions to support this three-park investment. The project partners with federal and state agencies and Friends of the Yampa in Steamboat, CO; the Yampa River Leafy Spurge project; Grand Canyon Conservancy; American Conservation Experience; Glen Canyon Conservancy; and will soon partner with Tribal elders and youth in biocontrol and incentivized harvest efforts.

The sum of these coordinated restoration efforts across Glen Canyon National Recreation Area, Grand Canyon National Park, and Dinosaur National Monument equals an innovative, dynamic approach to combating the complex challenges posed by invasive species in the Colorado River watershed. By combining scientific research, citizen engagement, and the latest ecological management strategies, these initiatives highlight the importance of holistic ecosystem stewardship. As Koller and Spencer shared, the success of long-term conservation will rely on continued collaboration, adaptive management, and public involvement. Even if short-term solutions like incentivized harvest and biocontrol are making tangible impacts—restoring balance to these iconic landscapes is not just a local effort but one of national significance—a joint, regionwide collaboration that will be imperative to protecting the biodiversity and cultural heritage of these American Southwest parks for generations to come.

About the Inflation Reduction Act

The Inflation Reduction Act provides the National Park Service with an historic opportunity to address critical ecosystem resilience, restoration, and environmental planning needs. Projects funded in national parks represent broad-scale and impactful resource investments across every corner of our nation—from Alaska to Florida to Maine.