HR: 1330h
AN: H52A-1144    [PDF]
TI: An Empirical Test of the Stream Power Law in Appalachian Plateau Fluviokarst
AU: Anthony, D M
EM: anthondm@purdue.edu
AF: Department of Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 United States
AU: * Granger, D E
EM: dgranger@purdue.edu
AF: Department of Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 United States
AB: Large caves on tributaries of the Upper Cumberland River, Tennessee, USA, record a wave of rapid river incision that advanced up the drainage basin in the Pliocene and Early Pleistocene. We model the passage of a knickpoint in this system as a perturbation to steady-state incision according to a simple stream power law, and test this model against dated river incision events at 7 caves. Model results suggest that values for the drainage-area exponent m are several times higher than those of previous studies. The upstream reaches of the study area are classified as fluviokarst, which is topography formed by the combination of fluvial and karst processes in areas where both soluble and insoluble rocks outcrop in the same drainage basin. In the upstream reaches of the Caney Fork and Obey River, surface drainage is generally interrupted due to diversion into the underlying karst aquifer. Base flow is entirely transmitted through the karst aquifer; the surface channel is occupied only during floods, which occur a few days or weeks each year. This exceptionally flashy discharge varies more strongly with drainage area than in non-karst watersheds, suggesting that values for m should be larger in fluviokarst settings.
DE: 1815 Erosion and sedimentation
SC: Hydrology [H]
MN: 2003 Fall Meeting