No fire retradant has yet been dropped in the Bull Run Watershed, although the U.S. Forest Service, which is fighting the fires in the Columbia River Gorge, has the authority to do so.
"The U.S. Forest Service will not normally make retardant drops in avoidance area," Oregon State Fire Marshal and Portland Fire & Rescue representative Lt. Damon Simmons said Thursday morning. "Number one on the list of avoidance areas is watersheds. Retardant is not dropped on watersheds unless there is an imminent threat to life."
The watershed is the primary source of water for Portland and much of the rest of the region. According to the Portland Water Bureau, which owns and operates the reservoir and distribution infrastructure in the watershed, the forest service said on Monday that it would use retardant if necessary.
But as of Thursday morning, the bureau says the fire is only at the outskirts of the protected area in the watershed. Its progress slowed overnight as temperatures and the wind dropped.
The use of fire retardant in the watershed is authorized by the Fire Protection Plan for the Bull Run Management Unit prepared and periodically updated by the forest service in consultation with the bureau and the Oregon Department of Forestry. The plan includes specific provisions for fire prevention, detection, and suppression. The plan and national policy prohibit the use of retardant near waterways.
The bureau says it has taken steps to prepare for the possible use of retardant. It continues to monitor water quality to ensure the water remains safe. In the unlikely event that any retardant enters the water supply, the most likely impact would be an increase in the water's nutrient load and a potential increase in algae production.
If necessary, the bureau is prepared to switch the water supply to its backup groundwater wells along the Columbia River.
The bureau says that is continuing to work closely with the Incident Command, which has the authority to manage the fire. In the event that retardant is used, the bureau will share that information with the public as soon as it is notified by U.S. Forest Service.
By coincidence, the bureau began blending the two water sources Thursday. The activation of the well field was in response to a temporary shortage of ammonia at the bureau's Lusted Hill treatment facility. Due to the shortage, the bureau was unable to treat a sufficient amount of water from the Bull Run to meet all customer demands. As a result, the bureau is blending groundwater at approximately 50 percent.
The shortage resulted from transportation delays. A delivery was expected within 24 hours, which will allow the bureau to return to 100 percent Bull Run.
You can read the fire protection plan at www.portlandoregon.gov/water/article/654687.