“ADOPT A SANDBAR” – A STUDENT PROJECT TO MONITOR CHANGES IN CHANNEL MORPHOLOGY IN BOQUILLAS CANYON, BIG BEND NATIONAL PARK, TEXAS

This project was designed to increase the critical thinking skills of students from a variety of departments on the Sul Ross State University campus by participating in a topographic and biological survey project in Boquillas Canyon, Big Bend National Park (BBNP). The participating students were selected from various backgrounds based upon their ability to contribute to the project, which was designed to assist an ongoing project in BBNP to monitor the status of a selected set of sand bars in the canyon. Specific content areas included GIS/GPS mapping, biology, hydrology of the Rio Grande, geology of the Big Bend Region, and the archeology and recent history of the canyon and the Rio Grande. The hydrology and biology of the river canyons in BBNP have become degraded over the past century as the result of prolonged low flow conditions caused by up-stream diversions and by the gradual appearance of invasive species such as giant river cane (Arundo donax) and tamarisk (Tamarisk spp., salt cedar). A feed back mechanism between dense stands of exotic vegetation and trapped sediment has transformed the river channel from a wide, mobile, meandering multi-threaded system with little riparian vegetation to a constrained, deeper single channel bound on one or both sides by high, stable sand bars fortified by dense groves of tamarisk and/or river cane. This shift includes a degradation of the aquatic habitat in the channel itself, along with the obvious degradation of the hydrology of the channel sand bar system. The project involved the use of canoes and survey equipment to conduct a 4 day float trip through Boquillas canyon with the specific goal of completing a series of topographic surveys of sand bars that have been the focus of previous similar surveys. One primary goal was to compare the survey results to previous surveys and to construct channel cross sections for hydrological modeling. The students were directly involved in the survey work. Additionally, informal lectures included discussions of career development, geology, biology, archeology and hydrology. The results of the surveying included the observation of significant changes in the morphology and vegetation on the sand bars due to the flooding that occurred in the Fall of 2008. Additionally, the work contributed to a base line of information for comparison in future efforts.