PRELIMINARY ANALYSIS OF CRITICAL ZONE PROCESSES IN THE ALPINE ENVIRONMENT, UNCOMPAHGRE WATERSHED, SAN JUAN MOUNTAINS, CO: A STELLA MODELING APPROACH

The Critical Zone of Earth is a natural system of hydrology, sedimentology, pedology, geomorphology, climatology, geochemistry, ecology, and humans. The critical zone is a surface-terrestrial, life-sustaining, heterogeneous, and complex environment. It extends from the top of the canopy to the bottom of the aquifer and encompassing the various subsystems on Earth. One of the most sensitive and fragile environments in the critical zone is the alpine. Unfortunately, humans have caused considerable degradation to many of these alpine environments through their various anthropogenic activities. One can ask: how have these activities impacted the various components and subsystems of the alpine? Understanding these impacts on this fragile environment requires observations at all scales, especially at the watershed scale. The Uncompahgre Watershed (2,888 km²) has been spatially and temporally impacted by numerous and various anthropogenic activities. These activities include: dams and reservoirs, mining, off-roading, logging, and alpine urban development. The Uncompahgre Watershed was analyzed from an integrated systems’ approach. Using STELLA® Modeling combined with field mapping and monitoring. The inputs, outputs, pathways, storages, and thresholds of the watershed were simulated. The various subsystems in the alpine were linked, which allowed the modeling of the flows of energy, mass, and transport allowing a deeper understanding. Field data and monitoring were used to calibrate the model. Long-term, USGS gauging data were utilized to add a temporal framework. The linkage of processes from one system to another has an influence throughout the critical zone in the Uncompahgre Watershed.