HR: 1340h
AN: H53B-1232    [Abstracts]
TI: Relationships Between Stream – Ground Water Exchange and Topography of the Channel, Valley, and Watershed
AU: * Payn, R A
EM: rpayn@mines.edu
AF: Colorado School of Mines, Department of Geology and Geological Engineering 1516 Illinois St., Golden, CO 80401,
AU: Gooseff, M N
EM: mgooseff@engr.psu.edu
AF: Pennsylvania State University, Civil and Environmental Engineering Department 212 Sackett Building, University Park, PA 16802,
AU: McGlynn, B L
EM: bmcglynn@montana.edu
AF: Montana State University, Department of Land Resources and Environmental Sciences 334 Leon Johnson Hall, Bozeman, MT 59717-3120,
AU: Bencala, K E
EM: kbencala@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd, MS 439, Menlo Park, CA 94025,
AU: Wondzell, S M
EM: swondzell@fs.fed.us
AF: U.S.D.A. Forest Service, Pacific Northwest Research Station, Forestry Sciences Lab. 3625 93rd Ave. SW, Olympia, WA 98512,
AU: Jencso, K
EM: kelsey.jencso@myportal.montana.edu
AF: Montana State University, Department of Land Resources and Environmental Sciences 334 Leon Johnson Hall, Bozeman, MT 59717-3120,
AB: Stream flow gains and losses represent exchange with groundwater and are commonly associated with the topography of the stream channel and contributing area. The magnitude of stream gain, i.e. runoff generation, is thought to be related to the extent and geometry of the contributing surface area. At smaller scales, the magnitude of both stream gain and loss may be related to heterogeneity in the gradient of the stream channel or valley. To validate relationships such as these between streams and their topography, we compare measurements of stream reach gains and losses to the terrain analyses of corresponding channels, valleys, and contributing areas. Comparisons are made for 26, 100-m reaches that constitute a 2.6-km long headwater stream in the Tenderfoot Creek Experimental Forest (USFS), Montana. The stream drains a 5.5 km² catchment with a riparian area of 0.073 km², delineated by contributing area with elevation within 2 m of the stream channel. The study stream flows over 3 geological units with valley slopes around 6.7, 5.7, and 9.0%, from upstream to downstream. For each 100-m reach, upstream and downstream discharges were measured using conservative tracer (chloride) experiments and dilution gauging techniques. In addition, the upstream release was measured at the downstream end of each reach to determine tracer mass loss and to estimate gross hydrologic loss over the reach. To close the mass balance, gross gain was calculated from the net change in discharge and gross loss. The spatial distributions of gross gains and losses were determined at multiple times during the declining summer baseflows of the snowmelt driven hydrograph. At lower baseflow conditions, several net neutral or gaining reaches also showed a 5-15% tracer mass loss, indicating that gross gain and loss operate concurrently in these reaches. We use these water balance fluxes to indicate one scale of stream – ground water exchange, and we compare patterns in exchange with the surrounding topography. Elevation data for the stream and watershed were collected using traditional survey techniques and aerial laser swath mapping (ALSM, 1-m resolution). Topographic metrics, such as channel sinuosity, valley slope, riparian area, and lateral contributing area, are calculated through terrain analyses of elevation data. Comparing topography with stream water balance is a spatially explicit approach to linking watershed structure with stream – ground water interaction, which is important to understanding solute fate and transport among the stream and adjacent ecosystems.
UR: http://www.mines.edu/~mgooseff/web_research/hydroscapes.html
DE: 1800 HYDROLOGY
DE: 1825 Geomorphology: fluvial (1625)
DE: 1830 Groundwater/surface water interaction
DE: 1839 Hydrologic scaling
DE: 1860 Streamflow
SC: Hydrology [H]
MN: 2007 Fall Meeting