The Upper CLP watershed was impacted by two major wildfires in 2012. The Hewlett Gulch Fire (May 14 – May 22) burned 7,685 acres and the High Park Fire (June 9 – July 2) burned 87,415 acres of mixed severity. The two fires were in close proximity to each other creating a contiguous burned area of approximately 95,000 acres in size. The burned area includes sub-watersheds that drain both to the Mainstem, including the South Fork, and into Seaman Reservoir on the North Fork Poudre River.

The 2012 wildfires had dramatic impacts on the Upper CLP landscape and vegetation that affected the hydrology and water quality within and downstream of the burn scars. The Source Watershed Program has been evaluating the impacts of the wildfires on background (non-storm event) water quality and storm event water quality.

Changes in some background water quality parameters are apparent, but are generally small and have not affected drinking water treatment. In contrast, rain storm events have been shown to produce rapid and dramatic changes in water quality, although these events are generally short-lived (several hours). During periods of impaired water quality, the Poudre River raw water supplies are shut off until conditions improve. A detailed report on the initial effects of the recent wildfires on water quality is also available.

In response to storm events, Utilities deployed an early warning system upstream of the Poudre River water supply intake immediately after the wildfires. The early warning system alerts water treatment facility personnel of degraded water quality in the Poudre River during flooding and debris flow events and provides water treatment facility operators adequate time to shut down the Poudre River intake.