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Environment

Colorado fish are catching the brunt of continuing drought, wildfire runoff

Aquatic life has already seen its habitat diminished significantly in the throes of drought

One of the “tens of thousands” of fish that died in the Animas River after runoff full of ash and sediment from the 416 fire turned the river dark brown. (Joe Lewandowski, Colorado Parks and WIldlife)
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In the midst of a drought-choked summer, Joe Lewandowski stood on the bank of the Animas River near Durango and watched the fish die.

Mountain runoff after a mid-July rain scraped the burn scar of the 416 fire, which raged for two months about 10 miles north of the city. That clouded the water with ash and sediment. The fish — which included a mix of brown and rainbow trout, bluehead and flannelmouth suckers — poked their heads above the surface of the opaque river. Some struggled toward the bank. They were searching for clear water so they could take in oxygen, virtually gasping for breath.

But with gills clogged by the residue of the runoff, they couldn’t survive.

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Later, workers with Colorado Parks and Wildlife would dip their nets in the chocolate-milky current and pull out dead fish by the tens of thousands. Lewandowski, spokesman for the agency’s Southwest Region, connects the dots between massive fish kills like that and an  all-too-familiar scourge — drought.

Hot, dry weather, part of a trend that now has extended to years in Colorado, made the forest prime tinder vulnerable to wildfire. Lower-than-normal snowpack made for feeble flows on many rivers and streams. What water did wash down from the high country picked at the scab of the loose, scorched earth.

And the fish caught the brunt of it.

“There’s so much floating debris, soil and ash in the water that got pushed down the hillside from the burn scar,” Lewandowski says. “If this was a normal year, more fish would have survived — the runoff would have been heavier and that sediment and ash would have been more diluted in the water.

“But as low as the water was, it crowded out the oxygen.”

The wildfire debris-clogged Animas River in southwest Colorado earlier this summer. (Provided by Colorado Parks and Wildlife)

Aquatic life has seen its habitat diminished significantly in the throes of drought. Lewandowski says the flow of the Animas River is about 30 percent less than a decade ago, thanks to subpar snowpack — about half of normal this year — and less runoff.

As the first week of September came to a close, the Animas River was running at 120 cubic feet per second (cfs), when a normal flow would be closer to 500 cfs. Often, the summer monsoon bolsters waterways’ capacity, but this year the storms hit hard to the south, in New Mexico and Arizona, but largely missed southwest Colorado — although rain did help tamp down the wildfire that burned nearly to the end of July.

But that proved a mixed blessing. Land burned clean of vegetation offered uninhibited flow of rainwater — and everything in its path — into one of the creeks that drained into the Animas. A bad break for the fish.

“The long-term forecast is more of a normal winter, and we hope to see that,” Lewandowski says. “But you don’t know. We’re just at the mercy of the weather.”

And the weather has been merciless.

Eleven months into the current “water year,” which runs from Oct. 1 through Sept. 30, Colorado had reported the third warmest and fourth driest periods in 123 years of record keeping. Ahead of this year on the scale are the water years 2002 and 2012, underscoring the recent string of drought years visited on the state.

“Colorado is warming, and it is likely to continue to warm,” says Taryn Finnessey, senior climate change specialist for the Colorado Water Conservation Board. “And so that means things are going to get thirstier. Precipitation as a whole we don’t know. But we know that temperature is enough of a driver that it results in less available water.”

Although drought isn’t a new concept to arid Colorado — nine of every 10 years, some portion of the state suffers some level of drought, Finnessey says — a warm or hot drought tends to carry a greater impact than a cold drought because it dries up the soil.

There’s a way to measure how “thirsty” an area has become. Experts track evapotranspiration, the rate at which water evaporates, combined with how much water plants draw from the environment. The agricultural community of Olathe, like several others in Colorado, this year experienced its thirstiest year on record.

“We have an increasing trend in drought over the last 30 years, and we’re seeing it as more frequent, persistent and intense,” Finnessey says. “That’s based on observations, not forecasting. It is definitely impacting people already. Drought used to be this creeping disaster, but more and more folks are realizing that it carries huge economic impact.”

Wildfire has only exacerbated the situation. Even the Hayman burn area, scorched 16 years ago, has been slow to recover due to a soil type that has been hard to stabilize or support vegetation, says Tammy Allen, restoration and protection unit manager for the Colorado Department of Public Health and Environment.

The agency also has worked with partners dealing with the 2012 High Park burn scar in Larimer and the damage left from the Waldo Canyon fire near Colorado Springs that same summer.

In the past few years, CDPHE has addressed debris from burn scars flushed into local waterways after wildfires torched acreage in Custer County as well.

“It’s a long-term recovery scenario for a number of these places,” Allen says.

But the news isn’t all bleak.

Last week CPW surveyed some short stretches of the Animas River to get at least a cursory estimate of the damage and found … live fish. There weren’t many. But the discovery pushed aside fears that all may have been lost. Some aquatic species likely were saved by small springs that furnish relatively clear water or possible seeps along the riverbank where water may have filtered to the surface from the aquifer.

Rainbow and brown trout can be restocked in the river from fisheries all over the state. But the bigger concern is native species that haven’t propagated in large numbers: the bluehead sucker, the flannelmouth sucker, sculpin and speckled dace to name a few.

“These are fish that have been in rivers for thousands of years,” Lewandowski says. “They could be placed on the endangered species list at some point. That’s the concern, their habitat has been so altered over the years that they could end up on the list. Our job is to make sure they  don’t.”

But he also understands that climate conditions could make that a challenging proposition.

“The bigger concern is if this drought were to continue for five or 10 more years, the vegetation dies and changes, the habitat degrades over time along rivers,” Lewandowski says. “A lot of riparian plants — willows and cottonwoods and others — could die and you have less shade on the water, less thermal cover. And there’s not a hell of a lot we can do about it.”