Dozens of trout and carp could be seen dotting the river in east Fort Collins on Friday. Erin Udell, email@example.com
It’s hard to solve a mystery without a smoking gun.
The unexplained 2018 fish kill on the Poudre River was no different. Colorado Parks and Wildlife announced Thursday the end of its investigation of the Fort Collins fish kill, estimated to have included more than 10,000 fish, without finding a definitive cause.
The agency faced obstacles in the investigation. Chief among them: Water quality on that stretch of the Poudre River isn’t continuously monitored. But that’s changing.
A collaboration between the city of Fort Collins, Colorado State University and In-Situ, a Fort Collins-based manufacturer of water monitoring equipment, is bringing real-time, extensive water quality monitoring to the Poudre River for the first time.
Fort Collins and other entities already monitor water quality in the river, but that generally means taking periodic samples of water and analyzing them in a lab.
“That doesn’t tell us very much about what happened before, during or after some event,” said Eric Robinson, application development manager at In-Situ. “I like to compare it to taking a picture of something as opposed to filming it. You can collect everything that happens during the lifespan of that area, see events that occur and track them down the river.”
The water quality data will also shed light on how human activity — agriculture, urban runoff, dams and more — is transforming the Poudre. That’s fortuitous timing as we get closer to federal verdicts on a gamut of reservoir projects expected to take a huge swig out of the river.
“Monitoring is the best way we can gauge how new interventions affect the water quality in the river,” said Matt Ross, assistant professor of ecosystem science and sustainability at CSU. “It’s vital that we have these (monitoring systems) go in now” so we can make informed decisions about the river and land use in the future, he added.
The project will initially include eight monitoring stations on the Poudre, stretching from CSU’s Mountain Campus in the canyon to the Fort Collins archery range north of Horsetooth Road along Interstate 25. Six have already been installed; two are pending negotiations with private property owners.
The monitors will measure water level, temperature, turbidity (cloudiness), depth, pH/oxidation-reduction potential, dissolved oxygen, conductivity and chlorophyll concentration. A cellular unit in each station will relay the measurements to the cloud, where the raw data will be stored. Ross and his lab will manage and visualize the data so the city can display it online or in public buildings.
The data stream will also help city staff respond to and report incidents faster. That’s crucial for Fort Collins Utilities, which gets about half its drinking water from the Poudre and also discharges treated stormwater and wastewater downstream. The city always tests water when it’s taken off the river for drinking or returned to the river, but staff have never before had access to continuous monitoring data across a wide stretch of the Poudre.
“We’re really impacted by the water quality in the river,” Fort Collins stormwater quality engineer Basil Hamdan said. “If somebody dumps something in the river, we need to know what’s going on as soon as it happens.”
This kind of monitoring is rare on a medium-sized river. The U.S. Geological Survey monitors water levels and sometimes water quality on waterways throughout the country, but funding and staffing constraints limit the expanse of its efforts. The Poudre River collaborators are hoping to expand the network with more monitoring stations and inspire other municipalities and researchers to embark on similar missions for other rivers.
“Prior to this, (the Poudre) was pretty good in terms of its monitoring relative to many other rivers of its size,” Ross said. “Now I’d say it’s one of the best in the country.”
Ross called the Poudre a classic Western river because it faces many archetypal Western challenges. Fire risk threatens water quality, large amounts of water leave the river for agricultural use and return in an altered form downstream, and urbanization creates sources of water pollution.
He’s especially excited that the monitoring stations will allow the collaborators to study the Poudre longitudinally, meaning they’ll be able to see how the river changes as it flows from the canyon through Fort Collins. That kind of monitoring likely could have helped the people investigating the 2018 fish kill identify a conclusive cause.
Fish kill investigation results
Fish health tells you a lot about the state of a river. On Sept. 20, 2018, the Poudre wasn’t exactly thriving. Fort Collins had just ended a 7-day streak of high temperatures above 90 degrees. The river reached a low of about 6 cubic feet per second and 6 inches high at the Lincoln Street gauge that day. Water levels were at a trickle because of weather and high demand for water from downstream users.
The morning of Sept. 21, the extent of the fish kill was unmistakable. CPW staff removed 1,290 dead fish from a 1.4-mile stretch of the river, from Lemay Avenue to Timberline Road. Based on 2017 population estimates, the actual toll was more than 10,000 fish, mostly longnose dace, white suckers and brown trout. Other species lost were rainbow trout, green sunfish, bluegill, largemouth bass, longnose sucker, Johnny Darter, mountain whitefish and common carp, according to a CPW news release.
CPW suspects low flows, high temperatures, possible contamination from several sources and mechanical problems at the city of Fort Collins water treatment plant all contributed to the fish kill. But a surge of water in the days following the fish kill quickly diluted whatever contaminants that might have been in the river at the time of the die-off. The river rose to 150 cfs — 25 times the volume it contained the day of the fish kill — by Sept. 23.
“There was a whole myriad of factors involved here, and it was the accumulation of them,” CPW northeast region manager Mark Leslie said in the CPW news release. “Unfortunately, with a major push of water following the event, we lost a lot of evidence that would help us pinpoint the responsible source or party.”
The good news is CPW has seen some fish recovery in the stretch where the fish kill happened. Some species have bounced back, while others will need more time. But barring another unexpected incident, fish populations will return to normal levels on the Poudre through Fort Collins, aquatic biologist Kyle Battige said.
The other silver lining of the fish kill is that the event partially inspired the water quality monitoring initiative.
“The reality is, there always exists the possibility that something like this will happen again,” Robinson said. “The monitoring systems won’t keep it from happening, but what they can do is provide us some kind of insight into what it was. With that information, proactive steps can be taken so that variable doesn’t affect wildlife in the river again.”
Jacy Marmaduke covers government accountability for the Coloradoan. Follow her on Twitter @jacymarmaduke.
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