The Willow Creek Watershed in the eastern Tobacco Root Mountains is an outdoor laboratory for teaching, research, and applied investigations. The setting is the centerpiece of the Department of Geological Sciences' field environmental programs in Montana, and provides a framework for cooperation and benefit among students, university researchers, county, state and federal agencies, and local ranchers. The towns of Pony and Harrison are located within the watershed in Madison County, Montana. This drainage basin was chosen because of:
- its proximity to the Field Station, and ready road access
- manageable size (about 160 square miles)
- the range of micro-environments with distinct ecosystems and land usage, ranging from alpine tundra to steppe prairies
- the presence of a large surface reservoir (Harrison Lake)
- diverse bedrock types, ranging from glacial deposits underlain by crystalline bedrock to thick unconsolidated sediments containing multiple aquifers
Key elements of the Demonstration Watershed include:
- Geological framework investigations, which are designed to understand the sedimentologic and hydrogeologic characteristics of the unconsolidated basin fill. These investigations consist of field mapping of surface exposures, analyses of drill cores and field determination of aquifer properties, such as hydraulic conductivity and storativity, and non-invasive geophysical surveys. IU graduate student Bill Elliott accomplished some of this work as part of his Master's thesis.
- Hydrologic monitoring, which involves deployment of electronic instruments for continuous measurements of water levels in aquifers, stream stages, micrometeorological conditions (such as wind profiles, humidity and temperature gradients, solar and terrestrial radiation, etc.), and snowmelt. Sally Letsinger's IU PhD work consisted of installation of many such instruments, and developed the data handling capabilites necessary to study their data. Descriptions of individual instrumented sites are accessible from the Willow Creek Demonstration Watershed Map.
- Computer modelling, which will implement algorithms for simulating snowmelt in rugged terrain, streamflow routing, and groundwater flow in heterogeneous porous media.
- Other studies that may develop from teaching projects (e.g., stream assessments, one of which was conducted by IU student Shawn Naylor in 1999), new questions (IU student Ralph Milliken studied snow geochemistry to investigate possible relationships with orography, or mountain geometry), and ranchers' needs (expanding this web site to provide for interactivity and automatic data uploading, which became available in Summer 2001).