Closures to start Monday at Gypsum Ponds as Colorado wildlife officials hit the reset button on trout fishery
Pond draining effort will also allow agency to install a new water level management system
Kendall Bakich/CPW
The Gypsum Ponds are scheduled to see closures starting Monday as the Colorado Department of Wildlife works to kill the remaining fish and install a water level management system known as Agri Drains at the state wildlife area.
While the ponds themselves — and the road to get there — will be closed during the construction, other areas of the 90-acre state wildlife area will be open, including access points to the nearby Eagle River. Anglers will be able to walk the road and access the river on foot, said Kendall Bakich, an aquatic biologist with Colorado Parks and Wildlife.
Wildlife officials are using the opportunity created by draining the ponds to install the Agri Drains, which will allow Parks and Wildlife to manage the water levels of the ponds better. The reset is aimed to return the ponds to the trout fishery, which they were originally intended to be.
The Gypsum Ponds were created by the removal of gravel in the late 1970s and early 1980s during the construction of Interstate 70 between Eagle and Dotsero. Few highway construction projects have enjoyed such a convenience — the gravel used to create the highway was mined from the land adjacent to it. The pits were then filled with water, and Parks and Wildlife received the land along with a piscatorial water right to keep the ponds full, diverting water from the Eagle River.
Parks and Wildlife stocked the ponds with trout every year, creating a fishery that is also used by migrating birds and is now home to a family of otters. But over the years, numerous other types of fish have found their way into the ponds, or “walked in” as Parks and Wildlife puts it, presumably through illegal stocking.
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Parks and Wildlife staff first documented the presence of restricted invasive fish species in the Gypsum Ponds during routine monitoring in 2010, Bakich said.
“Species that have walked into the ponds include smallmouth bass, green sunfish and black bullhead catfish,” Bakich said. “The most recent introduction was those catfish and they exploded, they were like the only fish you could see for a long time.”
Parks and Wildlife intends to restock the ponds after the Agri Drains are installed. The agency urged anglers to harvest fish from the ponds through an emergency fish salvage issued in June and has since drained the ponds.
Keeping invasive species out of the Eagle River
In the small puddles that remain, Parks and Wildlife is using a fish toxicant called Rotenone, an organic compound derived from the root of a tropical legume that has been used for generations to manage fisheries, going back to pre-Colonial times when Indigenous peoples used the root to capture and harvest fish.
The small puddles that remain couldn’t be completely drained or pumped out, and the Rotenone will kill every last fish that remains in those puddles. If it sounds extreme, it’s because the agency is extremely concerned about the invasive species migrating into the nearby Eagle and Colorado rivers and killing other fish.
“They can establish in rivers and predate upon our trout fisheries as well as downstream endangered fish,” Bakich said.
The nice thing about Rotenone, Bakich said, is it only kills gilled organisms like fish. If a bird or reptile or mammal encounters Rotenone, or eats fish that have been killed by Rotenone, they’re not affected.
“We’ve had bears laying in streams with fish that have died from Rotenone, piling them on their bellies and eating them, and it doesn’t have any effect,” Bakich said.
Bakich has gotten to know the local family of otters that lives near the Gypsum Ponds and said they won’t be affected, either.
“Last year the otters were running up and down the ponds while I was doing my survey,” she said. “One day, they raided my nets. This year they moved on once we started draining the ponds, but they’ll be back.”
The work is expected to take roughly two months. Once the Agri Drains are installed, the ponds will be refilled and restocked with trout.
The Agri Drains will allow Parks and Wildlife to manipulate water levels and exercise our water rights for the benefit of the fishery, Bakich said.
“When there’s a call on the river, we won’t have to stop diverting water into the ponds,” Bakich said. “We’ll be able to just flow the water through our ponds and not have to shut our operations down for senior water rights downstream.”
