Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: October 2, 2000
Publication Date: N/A
Technical Abstract: The purpose of this study was to determine the sediment deposition rates and carbon content of the soils in a riparian ecosystem. Profiles of deposited sediments in the riparian area and soils of the upland agricultural area were collected; the concentration of Cs-137 in each increment was used to determine the sediment layer deposited in 1954 and 1964. Sediment deposition rates for the 1964 to 2000 averaged of 0.39 plus or minus 0.20 cm/yr, while deposition rates for the period from 1954 to 1964 averaged of 1.30 plus or minus 0.44 cm/yr. Changes in rates of deposition between the two periods probably reflect changes in land use and agricultural practices in the watershed. Cs-137 in the upland agricultural soils was uniformly distributed in the tilled layer. Carbon content of the riparian profiles in the 0-5 cm layer averaged of 8.0 plus or minus 4.1 %. Carbon content of the 0-5 cm layer of the upland soils averaged of 1.7 plus sor minus 0.6 %. The riparian sediments (0-15 cm) have a fivefold increase in carbon as compared to the tilled layer (0-15 cm) of the upland soils, indicating that large amounts of carbon have been captured within this zone of sediment deposition in the riparian zone. The recent riparian sediments (0-5 cm layer - 8.0 % C) are enriched as compared with the older riparian sediments (30-35 cm layer - 3.4 % C). Rates of carbon buildup are higher than those that occurred in the pre-modern sediment of the wetland. These data suggest that carbon content in this riparian ecosystem is associated with increased sediment deposition rates.