DRAINAGE BASIN OUTLINE COMPLEXITY IN THE WATERSHEDS OF THE GREAT SMOKY MOUNTAIN NATIONAL PARK SHOW LITTLE CORRELATION WITH BASIN RELIEF

Drainage basin outline complexity and basin relief appear to have no correlation in the watersheds of the Great Smoky Mountain National Park (1006-1778 m relief range). This observed independence of watershed outline complexity from topographic relief matches results of previous studies, including a recent analysis of Great Lakes watershed boundary segments (up to 140 meters relief.)

The dataset comprises 16 drainage basins located within the Great Smoky Mountain National Park. All values are derived using USGS National Hydrography HU 10 digit boundary and USDA NRCS Watershed Boundary dataset sources. C_T, a measure of outline complexity, is derived as L_0.4/L₄, with L_0.4 being length of the boundary estimated with divider step size of 0.4 kilometers, and L₄ with 4 kilometer step size, expressed as per cent increase in apparent length.

Boundary complexities shown by C_T values for these basins vary significantly, ranging from highly irregular at 60% to nearly smooth at 8%, with a mean of 19%. Plots of C_T against overall topographic relief, relief relative to basin size, and relief over the square root of the area show no correlation (R² < 0.03). A simple self-similar fractal model for the outline of these basins, assessed by divider method, was only partly applicable in these results. However, for comparison to other studies, approximate D values ranged from 1.006 to 1.21 across the study area.

The Gatlinburg fault cuts through a significant number of the basins. This fault can be traced in a north east direction from the Telico basin through the Clear Creek French Broad River basin. Basins intersected by the Gatlinburg fault have average C_T value of 23%, while those unaffected show lesser level of complexity at 13%. The Clear Creek French Broad River basin has extreme outline irregularity (60%), while bordering three other basins with average C_T of 11%. Different basin placements relative to the fault may contribute to this surprising result.