LARIMER COUNTY, Colo. (CBS4) – Colorado’s largest fire on record, the Cameron Peak Fire, charred more than 208,000 acres in 2020. However, scientists and hydrologists fear the impacts the blaze will have on the Cache la Poudre River and Big Thompson River watersheds will likely last for at least a decade. Less than one year after the historic blaze, some municipalities had to turn off their intake from the rivers due to high levels of ash and sediment contaminating the rivers.

Colorado State University Hydrologist Stephanie Kampf said her team was already studying the clarity and flow of the Poudre River long before the historic blaze. However, when the fire charred its way past their equipment, ruining some of it, their studies changes to also documenting how the scorched landscape is handling watershed.

“Hydrology is the study of how water moves from the atmosphere through the soil and into streams and rivers,” Kampf said. “Whenever a fire burns nearby, we definitely pay attention in our field.”

In early July Kampf invited CBS4’s Dillon Thomas to a portion of the burn scar inaccessible by trails or roads. After hiking up a mountainside and over a ridge, walking through an oasis of trees that used to be, a set of tools stood largely unscathed by the flames from the year prior.

Of all the electronics and other tools in the mountainside, most survived the blaze. Some plastics on the tools were slightly melted, but most stood the test of time.

Wildlife experts say the impacts the blaze had on the fish in the rivers is already drastic, and will likely take years to recover fully.

Because of that Kampf and CSU were able to monitor how the fire impacted the watershed before, during and after the fire. Kampf warned, especially with surfacing data, that the impacts of the Cameron Peak Fire are going to linger for many years.

“The flash floods and the debris flows, those’ll usually settle down after a few years. But, there are other water quality concerns that will last longer,” Kampf said.

By plugging in her laptop to a set of tools Kampf was able to get a glimpse into the heart of the Cameron Peak Fire, and the ripples it has left in the water.

Kampf is now conducting tests in brooks for turbidity. Turbidity is cloudiness in the watershed caused by soot and sediment from the fire.

“Fires are a big deal for water because they affect in particular water quality,” Kampf said.

Most of the watershed along the 208,000 acre burn scar flows into the Poudre River.

“It’s a huge drinking water source and irrigation water source,” Kampf said. “And, so after fires, we tend to get some buildup of sediment that will come down into streams. Right in the watersheds that provide our source water, our drinking water supply.”

The water supply in the Poudre River alone provides water for more than six Front Range municipalities, and many more away from the Colorado I-25 corridor.

“Over one million people get their water supply from the Poudre River that has been impacted from the Cameron Peak Fire,” said Jen Petrzelka, Water Resources Operation Manager for the City of Greeley.

At the mouth of the Poudre Canyon, several miles away from Highway 14, a series of buildings are nestled along the foothills on a fenced-off property.

The buildings may appear to be warehouses from a distance. But, in each building is millions of dollars’ worth of equipment that treats millions of gallons of water each week. Some of those buildings belong to Greeley, where water is pulled from the Poudre River and treated before being sent dozens of miles east to the major Weld County city.

“Every time we have a rain event, you’re watching turbidity go up, sediment load goes up, (total organic carbon levels) go up,” said Andrew Kabot, Water Treatment Plant Manager for Greeley.

Kabot said the flooding of 2021, caused by burn scar’s inability to absorb water due to the blaze, has already posed a problem for the cities pulling from the river.

“(Increased toxicity levels) creates increased treatment costs, or we have to completely turn off our diversion,” Petrzelka said.

Kabot said Greeley has already had to shut off their intake from the Poudre River several times in 2021 due to increased levels of turbidity in the water. And, because the fire scorched such a large area, the city’s backups for water were also impacted.

“This fire is massive in size, it impacted every one of our high mountain reservoirs,” Kabot told CBS4’s Dillon Thomas. “We have (shut off the intake) three times this season so far.”

After heavy rain storms, the levels of toxins in the Poudre do not mix well with the price to treat it.

“If we didn’t switch sources, we may have to slow our plant down just to treat the sediment load because it’s going to be pretty heavy,” Kabot said.

“If any more of our watershed burned, that would definitely be a big issue for us,” Petrzelka said.

Petrzelka said Greeley was forced to strike an emergency deal with those who oversee Horsetooth Reservoir just west of Fort Collins.

“Water that they have in Horsetooth Reservoir, we’re able to trade and give them water directly from the Poudre River. So the water from Horsetooth is going to be cleaner,” Petrzelka said.

Around 90% of the burn scar falls in National Forest land.

The National Forest Service has a tight budget one which rid of their abilities to do proper management on the scar. Volunteers were tasked with coming in and fixing troubled trails and clearing them of toppled trees.

With a small budget and a huge demand, Greeley stepped up and helped secure funding for mulching along the same stretched of the canyon, hoping to expedite the scar’s ability to absorb water. The idea to provide material that can soak up water, and in turn prevent future flooding.

However, Greeley’s input alone won’t be enough to address the issue completely.

“It’s an incredibly expensive project, we’re looking at over 10,000 acres that need to be mitigated at over $40 million,” Petrzelka said.

Kabot feared the city will have to deal with the watershed impacts for many years.

“I’m going to guess we’re going to see the impacts of the Cameron Peak Fire for roughly 10 years,” Kabot said.

In that time, quite literally rising from the ashes, are blossoming signs of new life.

But, as researchers study the watershed and the surrounding landscape, some say we must realize we can no longer just go with the flow.

“We need to be prepared for the extremes that we might not have seen before,” Kampf said.

“Are you saying this is just the beginning?” Thomas asked.

“This is just the beginning,” Kampf replied.

Dillon Thomas