HILLSLOPE EROSION RATES IN THE OAK SAVANNAS OF THE SOUTHWESTERN BORDERLANDS REGION

Hillslope soil erosion on watershed landscapes can lower the productivity of upland sites and adversely impact water quality and downstream (off-site) areas. It is not surprising, therefore, that excessive soil erosion and the consequent sedimentation can represent significant costs to the land and people that are affected. The first known estimates of hillslope soil erosion rates on a watershed-basis in the oak savannas of the southwestern borderland region of the United States have been obtained on the Cascabel Watersheds. Initial estimates of soil erosion rates following the monsoon season of 2004 were reported by Ffolliott et al. (2005) and more complete annual estimates are presented in this paper. Comparable measurements will be made following prescribed burning treatments on the watersheds (Gottfried and Edminster 2005) to evaluate the impact of prescribed fire on hillslope soil erosion rates. STUDY AREA Twelve small watersheds established in the oak savannas on the eastern side of the Peloncillo Mountains of southwestern New Mexico to evaluate the impacts of prescribed burning treatments on hydrologic and ecological characteristics are (collectively) the study area. The aggregate area of these watersheds- called the Cascabel Watersheds- is 451.3 acres. They are located between 5,380 and 5,590 feet in elevation