Ashy water still posing problems over a year after the High Park Fire

“Everything changes when it burns,” said, US Geological Survey Research Biologist, Ed Hall.

Over a year has passed since the High Park Fire burned a scar onto the mountains of Fort Collins. Houses were erased from the landscape and trees burnt into skeletons. However, one of the largest problems facing Fort Collins after the smoke cleared is the water quality. Since day one, the ash, debris and charred bits left behind have found their way into Fort Collins water sources.


Estimates range from 87,000 to 90,000 acres burned according to Kevin Gertig, water resources and treatment operations manager for the City of Fort Collins.

Fort Collins Dual Water Supply

There are two sources of water in our city: Horsetooth Reservoir and the Cache la Poudre River. The Poudre is the main source, providing a minimum of 50 percent of the water supply, according to Gertig. Horsetooth Reservoir is part of a larger water allocation program, which determines water supply based on need.

The reservoir is intended to be supplemental. In 2012 the quota was maxed out and provided half of the water used in Fort Collins. The ash and debris had contaminated the Poudre, with no plants working as a natural filtration. And the Fort Collins need was great while the fires raged.

“Last year, during and after the fire, we were off the (Poudre) for three months,” said Donnie Dustin, water resources manager for Fort Collins utilities.

Even now, with heavy rain, the river turns a deep gray and the water can’t be used until it clears, Dustin said.

However, the city is still meeting demand, according to Lisa Rosintoski, the customer connection manager for the City of Fort Collins.

Fort Collins was on water restrictions starting April 1, but a wet spring ended the restrictions on June 1, Dustin said.

Cleaning the Water

There are two components to the water from the Poudre: sediment and ash. The sediment — sand, dirt and big particles — will settle given enough time. The ash is another story. The ash is so fine that it stays suspended in the water. Enough ash and sediment can turn the water into a thick sludge, which has caused countless issues on its own.


The water that can be treated is put through a presedimentation basin where the particles sift to the bottom.

Prior to the fire, Fort Collins only had one basin. But, once the need became apparent, another basin was erected to deal with the high sediment content. The sheer amount of stuff in the water had the ability to knock basins out of commission, as was the case in early June, Dustin said.

Sludge slides have pulled down trees and boulders, closing down roads near the burn area. The danger is delayed, as the sludge moves slowly and a rainstorm that ended an hour ago can still bring unexpected debris down the slopes. According to Gertig, a slide even knocked off a propane tank, misting the entire area with flammable gas.

Habitat Disruption

“Fire liberates a lot of stuff,” Hall said.

The ash in the river has also made the habitat dangerous for plants and animals in the river’s ecosystem. According to Hall, who has recently begun to study the effects of ash in water ecosystems, there are further problems created with the high amount of sediment and fire debris in the water.

“Ash shades the water column and the producers of the stream (plants and algae) can’t synthesize oxygen,” Hall said.

Research is ongoing for several different foundations, including the National Science Foundation. Although the slurry did not reach the water supply, Gertig said, there is still a large problem because of the amount of carbon in the river.

“It kills the biology of the river,” Hall said.

According to Hall, the river is better off just a year later, but research will continue on the Poudre.

Weather and Recreating the Landscape

“Weather is the biggest unknown that we have,” Gertig said.

Each rainstorm brings more debris into the water sources. Plants and trees were the main source of filtration for the Poudre watershed, according to Gertig. Without vegetation, the natural filtration is gone.

The process of restoring the land is called mitigation. The first step: seeding and mulching the burn areas. Last summer, mulch was dropped extensively over the burn areas, but a dry winter rearranged the mulch. According to Gertig, there just wasn’t enough moisture holding the mulch down.

Starting on Aug. 26, mitigation efforts began anew. With the aid of volunteers and workers, the City of Fort Collins will fell dead trees and drop mulch from helicopters.

“After the sirens and firefighters are gone, we’re in response,” Gertig said. “We will continue to be involved in this issue.”

Collegian Senior Reporter Mariah Wenzel can be reached at