HR: 0800h
AN: H51B-0451    [Abstracts]
TI: Transient Storage of Suspended Particulate Material in a New England Stream
AU: * Karwan, D L
EM: diana.karwan@yale.edu
AF: Yale University School of Forestry and Environmental Studies, 205 Prospect Street, New Haven, CT 06511, United States
AU: Saiers, J E
EM: james.saiers@yale.edu
AF: Yale University School of Forestry and Environmental Studies, 205 Prospect Street, New Haven, CT 06511, United States
AB: Suspended particulate material (SPM) poses physical, chemical, and biological concerns for water quality. These particles can disrupt the connection between stream and ground water, as well as serve as carriers for sorbed pollutants, such as heavy metals and phosphorus. Excess SPM can degrade overall stream habitat and ecosystem health. Although watershed sediment loads are often monitored, less is known about the hydrologic transport of these particles through the stream network to the watershed outlet or monitoring location. The in- stream transport of SPM can be influenced by transient storage mechanisms, such as settling and resuspension, stagnation in pools, exchange with the streambed or hyporheic zone, and entrapment on stream vegetation and behind coarse woody debris. A tracer injection experiment was performed in order to compare the hydrologic transport of suspended clay-sized particles, composed of titanium dioxide (TiO₂, 0.5 μm diameter), with that of a conservative solute, bromide (Br). The solute and particle tracers were added to a second-order, ungaged stream in northwestern Connecticut. Water samples were collected at six downstream locations over a 500 m stream reach, containing both run and step-pool geomorphology. A one-dimensional numerical model was applied in inverse mode to the measured breakthrough curve data in order to quantify the processes that governed solute and particle transport. The results of this analysis indicate that solute and particle transport was influenced by advection, dispersion, and transient storage. Transient-storage processes, particularly in pools, exerted influence on the transport of bromide and TiO₂ with different timescales of release. Bromide was often released more quickly from pools than TiO₂. Results of our analysis illustrate the mechanisms and relative timescale of SPM transport within a stream reach and provide insight into the potential response of SPM concentrations to elevated sediment inputs.
DE: 1860 Streamflow
DE: 1862 Sediment transport (4558)
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2007 Fall Meeting