HR: 08:45h
AN: NB51A-02    [Abstracts]
TI: Use of Buried Sediment Traps to Estimate Deposition of Fine-Grained Sediment and Organic Contaminants in Salmon Spawning Gravels
AU: * Anderson, C
EM: chauncey@usgs.gov
AF: U.S. Geological Survey, 10615 SE Cherry Blossom Drive, Portland, OR 97216 United States
AB: Deposition of fine-grained sediments into spawning gravels was estimated in the McKenzie River, OR, in conjunction with reservoir drawdown. Collapsed bags were buried at a depth of 40 cm during August 2003 and retrieved in July 2004. The deployment period included several mid-winter storms when sediment transport was high. Retrieval captured the column of bed sediment overlying the bags, including possible contaminants. Grain size distribution, percent and mass of fine material, chlorinated organic compounds, and organic carbon were measured in the retrieved sediment and pore waters. Deposition of fine materials was least in upstream reference areas, greatest in tributaries downstream of two different reservoirs, and intermediate downstream on the mainstem McKenzie River. Low-levels of organochlorine compounds were detected at two of the five sites, including below one reservoir where historical DDT spraying had occurred, and at the downstream mainstem location. The collapsed bag design, with Teflon lining, was an effective method to estimate time-integrated deposition of fine sediment and contaminants into a streambed.
DE: 1625 Geomorphology and weathering (1824, 1886)
DE: 1857 Reservoirs (surface)
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly