While the Alexander Mountain Fire didn’t quite reach Loveland’s city limits, it got too close for Loveland Water and Power’s comfort. Before it could be contained, the eastern boundary of the 9,668-acre fire crept to the edge of a major tributary and to within a mile of the city’s water treatment plant and Green Ridge Glade Reservoir, one of Loveland’s three main water sources.

While the water infrastructure was spared, the Big Thompson River basin that feeds it was less fortunate. The Alexander Mountain fire consumed 5% of its total area and left the landscape vulnerable to erosion and sedimentation, especially during storm events. This, in turn, poses a significant threat to the quality of Loveland’s water, potentially for years to come.

“Forests act almost like biofilters,” explains Tim Bohling, who runs the city’s water quality lab. “All of those plants and everything else help absorb nutrients and pollutants, and without them, those things go right into the watershed. So we’ve lost our primary treatment in that area.”

The challenge for Bohling and his team at LWP is now to ward off these dangers while simultaneously restoring the destroyed catchment area to health.

“It’s about public health”

In the short term, the biggest challenge to Loveland’s water supply is that heavy mudslides flow into the Big Thompson after heavy rains, causing increased turbidity and sediment pollution, Bohling said.

“A debris flow brings with it not only ash and ‘black carbon material’ but also sand, soil, tree trunks, branches and stones,” he said.

Not only will this make the river water untreatable, but large debris could also damage water infrastructure such as tunnels and bridges, he continued.

Over the long term, these mudslides will add sediment and biological matter to the water, potentially leading to increased algae growth, said Kevin Gertig, the city’s director of utilities. Contaminants from fire retardants and burned buildings can also linger in the watershed for years after a fire, so ongoing assessment and improved treatment are necessary.

The good news is that LWP already has a plan in place to mitigate these impacts thanks to lessons learned from the Cameron Peak Fire, which burned 208,663 acres in Larimer County in 2020, including 12% of the Big Thompson watershed.

“For us, this is a really good case study,” Bohling said of the previous fire. “… (Alexander Mountain) was a little bigger for us, closer to us, but less severe, so we expect similar events.”

These remedial measures include water quality monitoring stations installed upstream of the treatment plant. They provide real-time data to LWP staff and sound an alarm when contaminants or sediment are detected, giving them about two hours to redirect flow and switch to a cleaner raw water source, such as the canal or reservoir.

“We have one of the best, if not the best, water portfolio, which means our water rights are great,” Bohling said. “We can bypass many of these areas.”

In less cloudy times, Bohling and his team will conduct tests on water samples in the laboratory to evaluate different treatment methods, he explained.

All of this means that LWP believes it can protect Loveland’s reclaimed water from the fire, both from its immediate impacts and those in the years to come. But Gertig warned that future wildfires or other challenges to the city’s raw water supply, such as a drought, could put the city in a vulnerable position without further mitigation measures.

“The fundamental challenge we have in Loveland, as in all cities, is that we’re talking about significant investments,” he said. “…One of the challenges I face as director is that you have to balance that. But as a company, we have no choice. We are committed to a continuous, high-quality water supply, and that’s about public health.”

“When it comes to forest fires, cooperation is key”

Even better news is that LWP is not tackling this challenge alone.

A few days after the fire spread to the Charles Hansen tributary canal, a contractor with the Northern Colorado Water Conservancy District hydroseeded and planted straw wicker on the slope above to absorb the worst of the water.

“The canal carries water to Horsetooth Reservoir and also to Green Ridge Glade Reservoir,” said Jeff Stahla, Northern Water spokesman. “…We didn’t want a bunch of debris washing in there.”

Northern Water will continue to monitor the area and take additional remediation actions as needed. Meanwhile, several other partner agencies and organizations have already begun remediation of the watershed, including Larimer County, the U.S. Forest Service, and the Colorado Water Conservation Board.

“Wildfires require collaboration,” Gertig said. “…Many scientists and engineers will be involved, but there is no single institution that can take care of a wildfire.”

For longer-term solutions and resiliency projects, the city is partnering with the Big Thompson Watershed Coalition, a nonprofit organization formed to support recovery efforts after the 2013 flood and now helping clean up wildfire impacts itself.

“Much of our work is about forest health and reducing the need for forest fuels,” says the coalition’s executive director, Laura Quattrini.

Over the past few months, thanks to a grant from the state’s Wildfire Ready Watersheds program, Quattrini and the coalition have been working with other local sustainability organizations on an action plan to combat wildfires in the Big Thompson region.

Although the plan is not yet fully completed, Quattrini and her team are now using the information it contains to develop detailed models for the Cedar Creek watershed, which was most affected by the Alexander Mountain Fire.

“We’re going to create some models of slope erosion that will really help us by looking at soil types and rock formations,” she said.

The coalition and its partners are also waiting for models on hydrology, fire severity and debris flows, she added.

“We will bring them all together, overlay the maps and then see where in the landscape we can have the greatest impact with the reconstruction funds available to us,” Quattrini said.

Quattrini agreed with Bohling, saying the hard-won experience from the Cameron Peak Fire is helping emergency responders get a head start on the long recovery from the Alexander Mountain Fire. For example, Lori Hodges of the Larimer County Office of Emergency Management called together several fire rescue teams even before the fire was under control, she said.

“All the different players and partners that could potentially play a role already know each other and have built relationships,” Quattrini said.

While not an exact estimate, the coalition and LWP estimate it will take up to seven years for the watershed to recover from the Alexander Mountain Fire. Given climate change and a growing population, both expect to be working on these rebuilding projects while fighting to prevent the next fire.

“Every fire is different,” Gertig said. “But the potential for future wildfires is always there and we need to plan and contain them.”

Originally published: August 17, 2024 at 1:41 p.m.