Tuesday, August 3, 2010
Exhibit Hall A, David L Lawrence Convention Center
Background/Question/Methods:
Sedimentation and erosion are important processes that partially determine the ability of a wetland to sequester pollutants. This study quantifies sedimentation and erosion rates in two 1-ha experimental flow-through created wetlands in central Ohio. Twelve sites were studied for erosion based on reference to permanent boardwalks. Thirty-two sites within the two wetlands were layered with feldspar clay and given a year to undergo sedimentation or erosion. Eight of the 32 sites were equipped with wire fencing to estimate the net impacts of large animals. After one year, soil cores were taken and analyzed for bulk density, net accumulation, and nutrient concentrations. Influx and outflux rates of sediments, temporal vegetation changes, and muskrat proximity to sites were also recorded during this year. From these data, net sedimentation in the two wetlands is quantified, pollution sequestration ability is defined, and a detailed sediment budget for the wetlands is estimated. Net accumulation rates will be compared with a similar study done in 1998.
Sedimentation and erosion are important processes that partially determine the ability of a wetland to sequester pollutants. This study quantifies sedimentation and erosion rates in two 1-ha experimental flow-through created wetlands in central Ohio. Twelve sites were studied for erosion based on reference to permanent boardwalks. Thirty-two sites within the two wetlands were layered with feldspar clay and given a year to undergo sedimentation or erosion. Eight of the 32 sites were equipped with wire fencing to estimate the net impacts of large animals. After one year, soil cores were taken and analyzed for bulk density, net accumulation, and nutrient concentrations. Influx and outflux rates of sediments, temporal vegetation changes, and muskrat proximity to sites were also recorded during this year. From these data, net sedimentation in the two wetlands is quantified, pollution sequestration ability is defined, and a detailed sediment budget for the wetlands is estimated. Net accumulation rates will be compared with a similar study done in 1998.
Results/Conclusions:
Preliminary results show that erosion rates from May to July were statistically different from those measured from July to October. In late summer, erosion in the naturally colonizing wetland was 0.01 ± 0.02 cm day-1 while sedimentation of 0.07 ± 0.02 cm day-1 occurred in late spring. Similarly, the planted wetland experienced net erosion in late summer of 0.005 ± 0.02 cm day-1 with net sedimentation of 0.05 ± 0.02 cm day-1 in the late spring. The difference in erosion rate for the planted and naturally colonizing wetland were not statistically different for this time period.
