Sedimentation in the Bottomland Forest ♦ 159 Nutrient influx with sedimentation in a hydrologically restored bottomland hardwood forest in Midwestern USA

Exchanges of nutrients between a river and its floodplain forest are enhanced by sedimentation processes during flood pulses at a 5-ha bottomland hardwood forest located at the Olentangy River Wetland Research Park (ORWRP) in central Ohio. In the spring of 2000, the forest was hydrologically restored by notching an artificial levee that had separated the Olentangy River and its floodplain forest for many years. Thirty-two flat sediment traps (30 x 30 cm2) were used to collect sediment samples during spring/summer flooding events in 2003. Nine flooding events occurred in 2003 with flood durations ranging from 7 to 110 hrs. Results showed that sediment deposition is determined by landscape variability during flooding events. Net sediment deposit in the wettest area was 134 ± 12 g-dry wt m-2. Total N and C sedimentation ranged from 0.55 to 0.84 mg-N m-2 for nitrogen and 6.4 to 11.0 mg-C m-2 for carbon. The increased flooding pulses also bring in other nutrients and plant propagules, all of which will eventually lead to enhanced forest productivity and biodiversity