Transport of Fine Sediment Through a Wetland Using Radionuclide Tracers: Old Woman Creek, OH Christopher G. Wilson 1,* , Gerald Matisoff 1 , Peter J. Whiting 1 , and David M. Klarer 2 1 Department of Geological Sciences Case Western Reserve University 10900 Euclid Ave. Cleveland, Ohio 44106 2 Old Woman Creek, NERR 2514 Cleveland Rd. East Huron, Ohio 44839 ABSTRACT. The Old Woman Creek estuary (OWC), a coastal wetland in Ohio, traps 47% of incoming suspended sediment and has a sedimentation rate of ~1 cm/yr. Persistence of the OWC wetland and other coastal wetlands with high sedimentation rates seems problematic unless some previously trapped sedi- ment is exported from the wetland. Suspended sediment, 7 Be, and 210 Pb xs budgets for a single runoff event in the OWC wetland were developed to understand short-term sediment dynamics. The budgets were balanced by subtracting the sum of the imports from the sum of the exports and attributing the difference to either deposition on, or resuspension from, the wetland bed. The wetland exported 118 ± 2%, 93 ± 1%, 74 ± 2% of the delivered sediment, 210 Pb xs , and 7 Be, respectively, during the studied event. The 7 Be/ 210 Pb xs ratios of the total sus- pended solids and bed sediment were distinct from one anther and used to quantify the relative propor- tions of recently delivered and resuspended bed material in the sediment efflux from the wetland. The 7 Be/ 210 Pb xs ratios suggest that 26 ± 20% of the sediment efflux was resuspended from the bed. While the wetland trapped 13 ± 3% of the sediment it received during the runoff event, resuspension and removal of previously deposited sediment in the wetland was sufficiently large to result in a net loss of sediment from the wetland during the event. Thus, the Old Woman Creek wetland is a sediment sink over the long-term, but can be a net exporter of sediment during single events. INDEX WORDS: Sediment budgets, sediment, radionuclides, wetland, Old Woman Creek, Lake Erie. J. Great Lakes Res. 31:56–67 Internat. Assoc. Great Lakes Res., 2005 INTRODUCTION Coastal wetlands, like Old Woman Creek (OWC) in Ohio, filter influent water of sediment, nutrients, and pollutants derived from the tributary water- sheds (Klarer and Millie 1989, Mitsch and Reeder 1992, Mitsch and Gosselink 1993). Agriculture, sil- viculture, or urbanization in a watershed increases sediment input causing wetlands to accumulate sed- iment at an accelerated rate. For instance, sedimen- tation rates at OWC (~1 cm/yr) have increased nearly tenfold since pre-European settlement (Buchanan 1982, Reeder and Eisner 1994, Evans *Corresponding author. Current address: USDA-ARS, National Sedi- mentation Laboratory, 598 McElroy Dr., Oxford, MS 38655. E-mail: CWILSON@msa-oxford.ars.usda.gov 56 and Seamon 1997). Sedimentation may in turn de- crease the wetland’s ability to trap and store addi- tional sediment and contaminants (Whillans 1982, Evans and Seamon 1997). The fate of coastal wet- lands, like OWC, in the face of accelerated loadings and sedimentation that alter the wetlands’ ability to trap potentially harmful contaminants, prompts fur- ther study in the sediment dynamics of wetlands (particularly over the short term). In theory, one way to understand sedimentation in a wetland is through a sediment mass balance, which accounts for all imports and exports over a specific period. In practice, such a simple account- ing can be difficult because resuspension of previ- ously deposited sediment is common (Gabrielson and Lukatelich 1985, Sanford 1994, Lund-Hansen