HR: 1330h
AN: H52A-1179    [PDF]
TI: Are Lake-connected Streams Different in Ways Other Than the Connection? Implications for Studies of Stream-Lake Interactions in the Sawtooth Mountains, Idaho.
AU: * Arp, C D
EM: carp@biology.usu.edu
AF: Department of Biology, Utah State University, Logan, UT 84322-5305 United States
AU: Gooseff, M N
EM: michael.gooseff@usu.edu
AF: Department of Aquatic, Watershed and Earth Resources, Utah State University, Logan, UT 84322-5210 United States
AU: Baker, M A
EM: mbaker@biology.usu.edu
AF: Department of Biology, Utah State University, Logan, UT 84322-5305 United States
AB: In mountain landscapes, stream form changes rapidly downstream, though this continuum is modified by local controls such as valley confinement, knickpoints, and lakes. Streams flowing into and out-of lakes may have different geomorphic characteristics than watershed position would predict because lakes attenuate flows and trap transported sediment. Lake inflow and outflow stream geomorphology may also reflect the glacial structuring processes that initially created lakes in mountain regions. We began testing the hypothesis that lakes establish important fluvial geomorphic process domains that influence stream nutrient cycling and groundwater-surface water exchange by characterizing lake inflow and outflow stream and valley geomorphology in the Sawtooth Mountains Lake District in Idaho. We identified 30 paired inflow and outflow reaches, and 30 stream reaches not connected to lakes and quantified their stream and valley form and watershed position from 30 m digital elevation models (DEMs). Multivariate analyses of this data set indicate that while changes along downstream continua dominate, valley width, valley floor width, and longitudinal valley dynamics (widening or narrowing), along with variation in channel slope and drainage area, characterize differences among inflow, outflow, and unconnected stream reaches. Field measurements of 8 stream-lake systems (16 stream reaches) in this data set, including bankfull height and width, sinuosity, channel and valley gradient, bedform, and particle size distributions, were used in mountain stream classification systems. Preliminary results indicate that outflow streams have steeper channel gradients, larger mean bed material, and lower bankfull heights than paired inflow streams and that both inflow and outflow streams may not easily fit into established mountain stream classes. These results are considered in the context of stream hydrologic storage and nutrient cycling processes being concurrently studied in the Sawtooth Mountains.
UR: http://bioweb.usu.edu/biogeochem/SLI/stream-lake_interact.htm
DE: 0400 Biogeosciences
DE: 1824 Geomorphology (1625)
DE: 1845 Limnology
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting