Colorado Statewide Forest Resource Assessment

transport of materi als that can adversely affect water quality for human use;and serious alteration or destruction of aquatic habitat (CSFS 2002). The 1996Buffalo Creek Fire and 2002 Hayman Fire subjected Denver’s municipal watersupply to just this kind of damage and cost the Denver Water Board millionsof dollars for repairs and rehabilitation.Analysis: Forest management can reduce the risk of damaging wildfi re inhigh-priority watersheds by reducing competition, and enhancing appropriateage and species diversity, as well as overall forest resilience. In an effort toidentify the areas where this type of management could be most meaningfullyapplied, the CSFS chose to focus this analysis on forested watersheds ofimportance for drinking water supply. The assessment team worked with theColorado Department of Public Health and Environment (CDPHE) to identify642 sixth-level forested watersheds (typically 10,000 to 40,000 acres) witha direct link to critical infrastructure for municipal drinking water, such asintakes, reservoirs and trans-basin diversions. The forested portions of thesewatersheds cover 9.4 million acres and the primary forest types are spruce-fi r,aspen and ponderosa pine.These watersheds then were combined with a modeled geospatial analysisshowing areas of susceptibility to post-fi re erosion across the state. Keyfactors in this susceptibility analysis include vegetation, climate, soil type,topography and predicted fi re behavior. Approximately 5.6 million forestedacres in Colorado are at high to very high risk for negative impacts frompost-fi re erosion. The validity of this analysis was partially assessed by plottingpreviously documented incidents of post-fi re erosion over the modeledoutput. Nearly all of these incidents occurred in the very high categoryidentifi ed by the model, with a small percentage falling in the moderate andhigh designations.Map 14 – Important Watersheds for Drinking Water40