Some drought-imposed fishing limits have been lifted on the Colorado River
DENVER (AP) – Colorado lifted some fishing restrictions along a stretch of the Colorado River on Tuesday, but biologists warn the historically low water flows are due to a drought in the United States.
DENVER (AP) – Colorado lifted some fishing restrictions along a stretch of the Colorado River on Tuesday, but biologists warn that historically low water flows caused by a drought in the western United States, the High water temperatures and sediment from forest fires that deprive all trout of oxygen could force future bans.
On July 7, Colorado Parks and Wildlife imposed a rare, voluntary, 193-kilometer fishing ban. Tuesday’s changes allow anglers – a key driver of Colorado’s summer tourism economy – to fish a 43-kilometer (27-mile) stretch of river anytime between midnight and noon, when the waters are cooler . The restrictions have also been partially lifted 80 kilometers upstream.
The changes came after the release of upstream reservoirs, recent rains and a smaller amount of Colorado River cold springs that were diverted to the Denver metro area on the east side of the Continental Divide, Kendall Bakich said, Parks and Wildlife aquatic biologist.
Days of smoke from wildfires burning in western states have also deflected solar radiation that heats the river, lowering temperatures slightly, Bakich said.
“It’s crazy, but every little bit counts,” she said. “There have been such low flows starting this spring that the Colorado River looks more like a stream than a river. “
A multitude of factors, almost all linked to climate change, have left the fish of the Colorado River and its many tributaries in a precarious state. Climate change has made the American West much hotter and drier over the past 30 years. While cold-water trout thrive in temperatures below 65 degrees Fahrenheit (18 Celsius), biologists have recorded temperatures exceeding 75 F (24 C).
The Western Slope of Colorado also experienced minimal spring runoff from the high Rocky Mountain snowpack this year – runoff that typically flushes the river and replenishes high-quality fish habitat, Bakich said.
“The other phenomenon that we have never seen is the warming upstream” of the tributaries of the Colorado River, she added.
In recent weeks, sediment has been pushed into the waterway by microbursts of rain. This is particularly the case in Glenwood Canyon, much of which was charred by the 640-square-mile (1,657-square-kilometer) Grizzly Creek fire last year. The debris lowers oxygen levels in the water and scars the gills of the trout, Bakich said.
Species affected include brown and rainbow trout, mountain whitefish and sculpins which are a food source for larger fish.
For years, many environmental groups have protested the diversion of water to the Denver area, arguing that it is harmful to the drought-stricken Colorado River.
Denver Water, the state’s largest water agency, uses some of that water to serve 1.5 million people, or about a quarter of Colorado’s population. She is also looking for ways to meet demand while conserving water in times of drought.
Authorities have yet to implement mandatory fishery closures, largely because of a responsible local fishing community, Bakich said.
“Our fishermen are quite knowledgeable. They know when the conditions are good and when they are bad. The challenge is for people coming from outside the region, ”she said.
The voluntary shutdown earlier this month stretched from the town of Kremmling in north-central Colorado to the town of Rifle in the western state. Now anglers can fish between midnight and noon from the State Bridge on the upper Colorado River to Red Dirt Creek west of Glenwood Springs.
James Anderson, The Associated Press