HR: 09:00h
AN: H51H-05    [Abstracts]
TI: Hydrologic and Geomorphic Connectivity in the Little River Watershed, Tennessee, USA
AU: * Harden, C P
EM: charden@utk.edu
AF: University of Tennessee, 304 Burchfiel Geography Building, Knoxville, TN 379960925, United States
AB: Characteristics of low-order stream channels, and of the waters they convey, depend on characteristics of contributing area land surfaces, yet land-surface and stream processes are often treated separately. Land uses influence the amount and rate of water delivery to a stream and the chemical, biological, and particulate constituents of streamwater. At the local scale, connections between land and channel are physical and site- specific. For a given stream, then, under what conditions, where, and how frequently (in time and over space) does rainfall runoff enter the channel? What factors control these connections? Answers to these questions provide a first step toward identifying, mapping, and modeling connections and connected contributing areas in a watershed. This paper reports preliminary results of an investigation of visible, land-to-channel connections in low-order tributaries of the Little River, which flows into the Tennessee River in the Southern Appalachian Mountains. Land uses in this 611 km2, humid, temperate watershed are predominantly forest, agriculture, and low-density residential; industrial and urban land uses are also present. Results of site-specific, field-based analyses were used to develop a typology of the ways in which human activities increase hydrologic connections between hillslopes and channels in this watershed and to examine the spatial distribution and size range of each type. In the Little River watershed, roadways and cattle access paths in the riparian zone provide direct routes for runoff and sediment transfer from land to stream, but hundreds of small ponds, primarily in agricultural and residential areas, partially disconnect this system and change the relationships between contributing area land use and streams. The ponds are not apparent in hydrologic networks derived solely from digital elevation models, but they are so widespread that any effort to generalize the connections between land and channel in this area will need to incorporate their presence and define their role.
DE: 1622 Earth system modeling (1225)
DE: 1804 Catchment
DE: 1825 Geomorphology: fluvial (1625)
DE: 1826 Geomorphology: hillslope (1625)
SC: Hydrology [H]
MN: 2007 Joint Assembly