The Cost of Inaction: Flagstaff Watershed Protection Project Cost Avoidance Study

Wayne R. Fox.

This study estimates the potential financial damages mitigated by the implementation of the Flagstaff Watershed Protection Project (FWPP). The goal of FWPP is to reduce the threat of catastrophic wildfire and post-fire flood impacts by conducting fuel-reduction forest treatments in two watersheds critical to the City of Flagstaff—the Dry Lake Hills (Rio de Flag) and Mormon Mountain (Lake Mary). By thinning unnaturally dense vegetation and using prescribed fire in these areas, the risk of intense wildfire and post-fire impacts will be significantly reduced.

The primary risks of wildfire are two-fold: damage from fire and damage from resulting floods. Severe, uncharacteristic fire destroys trees, wildlife, and recreation value and threatens homes and infrastructure in its path. Floods occur in the areas downstream of burns and can cause severe damage miles from the fire itself. According to the University of Wyoming College of Agriculture and Natural Resources, increased runoff and erosion after intense wildfires on steep hillsides can increase peak runoff by up to 100 times the average flow. This happens after moderate to severe fires that burn the soil to the point that it is hydrophobic, and can no longer absorb water. After the 2010 Schultz Fire, which burned adjacent to the City of Flagstaff, flooding caused millions of dollars in damages to property in downstream neighborhoods. This study assumes that post-fire flooding would be similar to a 500-year flood event in the drainages below the Dry Lake Hills.

Full Article