Agencies won’t be able to operate crucial fish passages this summer
By Bob Berwyn
SUMMIT COUNTY — Historic low river flows already have put the squeeze on endangered native Colorado River fish in key tributaries like the Yampa, and the fish could take another hit because there won’t be enough water during parts of the summer to operate fish passages that enable species like the Colorado pikeminnow to reach spawning areas.
Along with the pikeminnow, the razorback sucker, bonytail and humpback chub are listed as endangered and under the jurisdiction of a cooperative, federal-led recovery effort. The four fish once ranged widely throughout the Colorado River Basin, but construction of dams and massive diversions destroyed most of their habitat. The native fish have also faced fierce competition from non-native fish.
Biologists said suspending operation of the fish passages this summer will have a short-term impact on the endangered fish, but are more concerned about long-term impacts if the drought lasts another year.
The endangered species evolved over millennia to survive extreme high and extreme low flows, but human activities have hit hard at the low end of the range, resulting in conditions that can’t sustain populations without help — like the fish ladders.
Overall, recovery program leaders say they’ll manage the little bit water they do have based on experience from the drought in the early 2000s.
“We’ve been there before,” program director Tom Chart said in a previous interview, explaining that this year’s low flows will likely result in a temporary setback for recovery efforts, especially in tributaries like the Yampa River.
There are places we saw on Yampa in 2002 where there was virtually no surface flow,” Chart said. “It was just a connected series of pools on the river. Native fish seem to have a propensity to vacate those places … but some of them don’t, and that’s the real concern.”
Low flows favor non-native fish, especially smallmouth bass, which in 2002 all but wiped out the Colorado River natives that were left in the system, Chart explained.
Smallmouth bass were introduced and managed as a popular sport fish and remain a desirable species in certain settings. But so-called bucket biologists complicated the native recovery equation with homegrown (and illegal) transplants of bass, Chart said.
Operating fish passages is critical to recovery of the species, but when it comes to water in Colorado, environmental values often take a back seat to all other uses. Fish passages play an important role in the life cycles of the endangered fish. The Colorado pikeminnow has been known to migrate up to 200 miles to spawn.
In a release, the U.S. Fish and Wildlife Service specifically identified the Grand Valley Irrigation Company Fish Passage, Grand Valley Project Fish Passage, and the Price-Stubb Fish Passage, all in western Colorado.
The passages were built as part of the recovery program to give the fish access to important habitat extending from Lake Powell to Rifle on the Colorado River and from Grand Junction to Delta on the Gunnison River.
On the Colorado River, agricultural irrigators in the Grand Valley are operating fish screens on their canals when conditions permit. The screens serve a dual purpose of preventing fish from entering canals and benefiting canal operations by reducing debris loads in the canals.
“We have a history of cooperation with the Recovery Program that helps our water users and the endangered fish,” said Richard Proctor, manager of the Grand Valley Water Users Association.
The Recovery Program is also coordinating with the Redlands Water and Power Company on operating procedures for the Redlands Fish Passage and Screen, located on the Gunnison River. The Recovery Program is working to minimize impacts to water deliveries to Redlands irrigators while continuing to operate the fish passage and fish screen, as conditions allow.
“We are grateful for the continued support of Grand Valley water organizations and other Recovery Program partners,” said recovery program director Tom Chart. “This cooperation is especially important during times of drought when sections of the Colorado and Gunnison rivers have the potential to go dry.”
Chart said the endangered fish did take a noticeable hit during the drought of the early 2000s, but bounced back nicely in subsequent years, when near-normal snowfall bolstered flows.
Overall, the recovery program has made progress, especially with the Colorado pikeminnow and the razorback sucker. The two chub species have been hit harder by the non-native fish, Chart said, adding that program is still on-track to meet its current goal of getting the fish off the endangered species list by 2023.
There are some small amounts of water in upstream reservoirs to help boost flows, but that won’t be enough to meet flow requirements this year. The target flows near the confluence of the Gunnison and the Colorado are about 810 cfs, but the recovery program will adjust that downward this year.
“When we get into years like this, the U.S. Fish and Wildlife Service adjusts those targets. It becomes a triage situation,” Chart said.
Filed under: climate and weather, Colorado, Drought, endangered species, Environment, rivers, water Tagged: | Colorado, Colorado River, Colorado River endangered fish, drought, endangered species, Gunnison River, United States Fish and Wildlife Service, Yampa River