CU Boulder study shows wildfires' downstream effect on water systems

The damage from wildfires stretches past just physical devastation, according to a new study from the University of Colorado. The report — funded by The Water Research Foundation — outlines the short-term and long-term effects of wildfires on municipal drinking water.

Wildfires can contaminate drinking water through the movement of ash, algae bloom and sediment runoff. The water flows downstream from an area affected by a fire and impacts watersheds. When the source water is affected, research showed that the water treatment process becomes significantly more difficult.

Fernando Rosario-Ortiz, the lead author of the study and an associate professor at CU, said cities should know when carbon levels are too high and how to take appropriate action.

"Essentially for drinking water, utilities need to consider the risk and evaluate that the water quality may be very different and (be) observant of the particles that may be in the water," Rosario-Ortiz said.

The number of wildfires and their duration have increased due to climate change. This raises concern as to whether the current water filtration systems can withstand the impact. In 2012, two wildfires threatened the water supplies of Fort Collins and Colorado Springs. The High Park Fire and Waldo Canyon Fire put the cities' entire water supply at risk. This is the outcome researchers are hoping to avoid.

To test the filtration process researchers conducted a wildfire simulation. Soil and deadfall were heated to 225 degrees Celsius, a temperature to simulate a medium-temperature wildfire. After being heated, the soil and deadfall were filtrated into tap water then treated with the standard treatment process.

They found that the heated materials were more difficult to process and responded poorly to chemical treatment. Rosario-Ortiz believes the Front Range is especially vulnerable to water contamination due to wildfires.

In addition to the research, the university held a workshop for approximately 50 water utility representatives June 5. The session included testimony from representatives in Fort Collins and Colorado Springs, members of the Water Research Foundation as well as suggestions to treat the contaminated water.

The report offers recommendations to fire-prone regions of the United States, including Boulder.Those include that cities become aware of the possible contamination wildfires have on the drinking water. Once cities are aware of these possibilities, they can begin to treat water accordingly.

"The city of Boulder draws water from the Boulder Creek and you can imagine the worst-case scenario," Rosario-Ortiz said. "If you have a wildfire near your source center, you're going to have impacts."