When the Smoke Clears: Aftereffects of Wildfires on Communities’ Water Quality

On November 8th, 2018, a fire started near Camp Creek Road in Butte County, California. Over the next 17 days that fire would ravage 153,336 acres of land, making it the deadliest and most destructive wildfire on record in California, and the sixth deadliest U.S. wildfire in recorded history. Five hundred miles south on November 8th, another fire started in Woolsey Canyon between Los Angeles and Ventura counties, ultimately engulfing 96,949 acres over the next 13 days. By the time both fires were completely contained, 89 people had lost their lives, tens of thousands of people had lost their homes and businesses, and the people of Paradise had lost their entire town.

The deadliest fire season in California history also spells trouble for community access to clean and safe water quality

It is impossible to overstate the tragedy of the Camp and Woolsey fires. The road to recovery will be a long, expensive, and painful one and, unfortunately, rebuilding is only the first of many costs. In addition to the obvious aftermath of a wildfire, there is a subtle yet salient issue these communities will now face: tainted water quality.

California’s forests supply more than 60 percent of the State’s water. Given that forests typically serve as the fuel source for wildfires, this means a significant amount of California’s water supply is at risk of wildfire contamination. According to the United States Geological Survey (USGS), “wildfires can compromise water quality both during active burning and for months and years after the fire has been contained.” While the fire is raging, ash can settle on lakes and reservoirs used for drinking water supplies. But even after the fire is extinguished, storms can further contaminate water supplies as burn areas easily erode and wash large amounts of sediment into streams, rivers, and reservoirs. This puts watersheds at greater risk of flooding and erosion.

This is precisely what occurred in the wake of the Camp and Woolsey fires. To add insult to injury, California experienced a significant storm event just days after full fire containment. The result, of course, was massive flooding and erosion of the recently scorched land, resulting in stormwater pollution. According to the USEPA, wildfires leave behind nitrogen and phosphorus nutrients, organic carbon and carbon combustion products (PAHs), and agricultural chemicals from charred vegetation; metals, such as lead, aluminum, mercury, and arsenic from burned structures; and changes to pH, sediment, and turbidity due to ash. Once introduced to a water source, these by-products pose a threat to surface and drinking water quality.     

The effects on water quality are both short- and long-term, as wildfires increase the costs associated with water treatment and the need for alternative supplies, as well as diminish reservoir capacity. According to the USEPA, wildfire impacts on water supply and water quality include:

Impacts on Drinking Water Treatment 

  • Increased solids and turbidity: increased filtration

  • Increased algae: increased filtration, pH adjustment, taste & odor, harmful algal blooms (HABs), and disinfection byproducts (DBPs)

  • Increased organic carbon (TOC): increased coagulation, membrane fouling, DBPs, biological activity, chlorine demand

  • Increased toxic materials (metals and organics): possible Maximum Contaminant Level violations

Impacts on Water Infrastructure

  • Burned out small water systems

  • Lost power or power infrastructure

  • Damaged or destroyed storage tanks

  • Lost service connections and meters at residences

Impacts on Distribution Systems

  • Water distribution system depressurization as a result of fire

  • Increased volatile organic compounds (VOCs), such as benzene

Impacts on Surface Water Monitoring

  • Increased solids and turbidity

  • Increased TOC

  • Increased total nitrogen (nitrate and ammonia)

  • Increased phosphorous

  • Change in pH levels

  • Increased metals (especially lead and mercury)

  • Increased arsenic and bromide

  • Total trihalomethane (TTHM) formation

In short, wildfires—past, present, and future—have a significant impact on domestic, agricultural, and ecological water supplies.

So, what can we do?

As a water community, we need to dedicate more resources to understanding the short- and long-term effects of wildfires on water quality, as well as the recovery process and possible preventative measures. The dismal truth is that wildfires are not going away. In fact, experts say California wildfire frequency could surge 50% by 2050, which means it is in our best interest to be proactive before matters worsen.

Beyond testing and data collection studies, there are also steps we can take as individuals to help ease the suffering of the Camp and Woolsey wildfire victims.  

A list of some organizations working closely with California wildfire survivors are:

To ensure that your money is providing relief to wildfire victims, you are encouraged to donate to charity organizations that have been approved by National Voluntary Organizations Active in Disaster (VOAD).