This summer’s hot temperatures and drought conditions have resulted in a record number of wildfires, particularly in Western states. But fires can take place anywhere, and just as they have been shown on the news burning down houses and neighborhoods, they can affect drinking water sources and treatment operations.
Vegetation stabilizes soil in a watershed and helps in the percolation of precipitation in the ground. When wildfires burn this vegetation, the soil runs off the land more easily, bringing sediments and debris to streams, rivers, lakes and reservoirs. This increase in sediment can cause numerous water-quality problems, including:
- higher turbidity, suspended solids, dissolved solids, and conductivity
- clogged intakes and greater sludge production
- elevated ammonia from fire retardants as well as higher levels of phosphorous, iron, manganese, and nitrate
- higher total organic carbon
- lower dissolved oxygen
- fish kills
- changes in pH and alkalinity
- unpleasant taste and odor
As an example, following a fire in Colorado, Denver Water saw dramatic increases in dissolved metals in the South Platte River, one of Denver’s main sources of raw water. Lead content soared from approximately 2 µg/L to 240 µg/L. The river water also had significant increases in arsenic, beryllium, cadmium, chromium, cobalt, copper, and vanadium.
What you can do
You can take steps to reduce the vulnerability of your water system to fire and its impacts. To reduce the chance of a fire reaching your facility, store fuels a safe distance from structures. Remove flammable vegetation from within 15 feet of a structure, and ask your electric utility to clear tree branches near power lines.
Make sure you have a dependable source of power, especially at remotely controlled components of your system, like tanks. Maintain adequate supplies of chemicals so you can modify dosages if you need to in response to higher turbidity, for example. Monitor raw water quality more often during and after fires. Be sure you have an option to use an alternate water supply. Completely fill your finished water storage tank(s) prior to an expected event that may compromise water quality.
Reach out to others in and around your community. Work with local fire officials, both to make them familiar with your utility and to have them identify potential hazards at your facility. Join a mutual aid group in your state or region, such as the Water and Wastewater Agency Response Network (WARN). You can find the WARN in your state at www.XXWARN.org [1], where XX is your state’s two-letter postal abbreviation.
The Colorado WARN [2] has compiled comprehensive lists of suggestions for fire planning as well as an array of resources applicable to other states. More information [3]