CORRELATING FLUVIAL GEOMORPHOLOGY AND TAMARISK POPULATION ON THE COLORADO RIVER WITHIN CANYONLANDS NATIONAL PARK, UT

Canyonlands National Park hosts some of the most contrast canyon and river landscape on Earth. The Colorado River bisects the park and attracts thousands of park visitors a year to boating activities ranging from calm to world-class whitewater. The non-native vegetation species, Tamarix, has acclimated well since introduction in the 1950s and has established along the park river corridor in a variety of geomorphic settings. The Tamarix species has induced aggressive eradication efforts because of its ability to increase soil salinity, reducing viability of native species, and to produce abundant fire-prone leaf litter. Gradient and sinuosity vary greatly along the fifty miles of park owned river segment, as do the zones of sediment deposition and scouring. In park restoration efforts, the question asked is what geomorphic settings are most prone to support Tamarix species and which are most likely to support resurgence of native species? In this study, aerial photographic analysis and field investigation were employed for a first round assessment of the geomorphic and vegetative associative patterns along the Canyonlands section of the Colorado River system. The river system is considered spatially from watershed scale to individual reach and temporally from the early 1900s to modern day with consideration to annual peak discharge and sediment delivery. Specific patterns do emerge where Tamarix thrive in calm eddy waters and are scarce to non-existent in fast water and debris fans.