Student Research Projects

Delineating Small Drainage Basins Within Piedmont Geological Formations Using ArcGIS

Student Allegra Hawkingberry, '17
Grace Lamay, '17
Faculty Mentor(s)
Department Earth and Environmental Sciences
Course EES 489: Research in Natural Sciences


Watersheds can help in identifying the rock composition of a geological formation. This is extremely beneficial in the Virginia Piedmont because the region has immensely poor outcrop exposure, remarkably thick soils, and dense vegetation making it problematic to get an accurate depiction of the geology in the area. Analyzing stream sediments can aid in getting a better understanding of the underlying rock formations based on the composition of the diverse grains in the collection. Finding a waterbody that drains into a watershed that contains only one geological formation is critical to determining the composition of that unit. To find these sample areas we found topographic maps of the Virginia Piedmont region and used a number of ArcGIS tools, including the hydrology and clipping tools, to develop an accurate geological map with hydrologic information. Mastering the skills of the hydrology tool offered in the ArcGIS program we were able to use digital elevation models to delineate the watersheds in the Piedmont region of Virginia. We took sand samples from the quadrangles of Tungsten, Wightman, and Clarksville Virginia. Within the Wightman Quadrangle samples were taken from the hornblende diorite-gabbro unit, the biotite tonalite unit, and the fine-grained felsite unit. Within the Tungsten quadrangle a sample was taken from the biotite metagranodiorite to quartz monzonite unit. The next step for this project will be to analyze the composition of the samples collected.