RANGELAND WATERSHEDS: INTEGRATED MONITORING AND MODELING WITHIN A GIS

Presented herein is a protocol for developing a monitoring program for assessing the overall hydrologic stability of rangelands at the watershed scale. Rangelands dominate the world land area (47 percent) and are greater than 70 percent of the area of the western United States. Erosion and sedimentation issues are the predominant land and water quality issues of rangeland areas. A variety of processes deliver non-point source pollutants to streams within rangeland environments, and human actions frequently modify these processes and increase the rate of soil loss. Increased rates of soil loss not only reduce long term sustainability of the upland ecosystem, but may also increase the rate of sediment delivery to the drainage network therein affecting both stream condition and water quality. Monitoring to determine trends in soil loss rates from rangelands is therefore a critical element in managing the sustainability of these ecosystems.Recent emphasis on ecosystem management has forced natural resource managers to evaluate and manage rangeland ecosystems at much larger scales and for more diverse resources than has been undertaken in the past. Unfortunately, holistic monitoring approaches, designed to define environmental changes and the causes thereof across large areas and multiple resources, are few. The major product of the research is a watershed-based monitoring protocol that will help managers monitor and understand the cause of erosion- and sediment-related environmental changes in a watershed. The protocol uses GIS technology and conceptual and mathematical models for its implementation.