Will Large Scale Forest Restoration Treatments Provide More Water for Population Growth in the Semi-Arid West: Current Hydrologic Research in Arizona

Ponderosa pine forests in the western United States are undergoing restoration treatments in form of tree harvesting and prescribed fire on an unprecedented scale to reduce the risk of catastrophic, stand replacing wildfires, especially in the Wildland-Urban Interface (WUI). National Forests within the ponderosa pine region of the Interior West are realizing early on in their NEPA analysis process for fuels treatments that there is a gap in watershed response data. In past forest watershed research, fuel treatments, specifically thinning in combination with prescribed fire, were never properly evaluated by watershed-scale research studies. The Mogollon Rim Ranger District, Coconino National Forest, Arizona, determined in its planning process that it needed to obtain watershed response information, namely watershed yield, peak flows, as well as soil and vegetative responses on a watershed scale, in order to prepare adequate NEPA documents for future fuels treatments. The District's plan to implement a fuels reduction project both within and outside of the WUI within the Beaver Creek Experimental Watershed presented a unique opportunity to expand upon existing knowledge, and fill in critical treatment-effects information gaps. This effort will help not only the Mogollon Rim Ranger District, but also other National Forests in the Arizona ponderosa pine region as well as land and fire managers throughout the southwest. The study utilizes the existing watersheds of the Beaver Creek Experimental Watersheds south of Flagstaff, Arizona. Five watersheds (between 76 and 722 ha) were reinstrumented with new stream gages in 2006. The restoration treatments planned by the Coconino National Forest include varying combinations of mechanical thinning and prescribed burning. This paper describes the research and monitoring efforts conducted for this.