Wildfire Pollution Affects Water Supplies

Wildfire Pollution Affects Water Supplies

Wildfire pollution affects drinking water to the point where consumers can see, smell and taste the pollutants. Water utilities face a threat to water quality.

Wildfire pollution is so bad in Western states that it has affected water quality in numerous communities. Water utilities must prepare for this constant threat to water quality.

An unanticipated side effect of intense wildfires is poor water quality that results from pollutants that enter municipal and community water system sources. As fire intensity and frequency increases due to the impacts of climate change on local weather systems, managing pollutants that impact water systems will become increasingly necessary.

One of the most destructive wildfires in California, the Camp Fire, burned over 150,000 acres and destroyed more than 18,000 structures. In addition to vegetation, the fires burned building materials, electronics, household goods and automobiles. Pollutants from those materials made their way into waterways where they impacted water quality.

Residents downstream of burn areas that rely on fire-impacted water sources often complain about smoke-tainted odors in their tap water, and in some cases, municipal water suppliers have had to stop sourcing water from locations near burn areas.

Researchers who have conducted field studies on downstream water quality after several severe wildfires have looked at not only the effects on surface water quality, but also the impacts to water treatability, or “the ease with which water is purified” following wildfires.

Fires cause changes to the amount and composition of dissolved organic matter in water, which can hamper a treatment plant’s ability to produce quality drinking water. Dissolved organic matter can cause off tastes and discolored water, it can cause increased microbial growth in water, and it can foul treatment membranes and other treatment processes. The result is increased treatment costs and treatment chemical needs. Researchers found that the amount of dissolved organic matter that leached into the water was related to how intense the fire was.

Additional impacts include post-fire releases of nutrients from burned materials that increase the chances of harmful algal blooms. Fires also burned materials from structures as well as plastic piping associated with water systems, releasing toxic chemicals into water systems. In addition, changes to local hydrology, such as decreased soil permeability can cause runoff that carries more pollutants into waterways that eventually settle into lakes and reservoirs that act as source water for treatment systems.

Prescribed burns can help reduce the amount of organic matter that could potentially burn and protect areas with infrastructure from burning. In addition, utilities near fire-prone areas or those that rely on water sources in fire-prone areas can develop risk analyses and emergency response plans that include things like identifying alternate water sources, instituting water monitoring programs and modifying treatment programs to handle new pollutants.