Characteristics and Long-Term Sedimentation Patterns of Wetlands
1997
Downer, Charles W. | DeLaune, Ron | Nyman, J. A.
Wetlands were constructed in the Grenada Lake fluctuation zone during the late 1950s shortly after construction of the reservoir. These wetlands were planted with grain to attract waterfowl for hunting and were termed shooting ponds. After a change in the rule curve of the reservoir caused more frequent flooding of the shooting ponds, planting and water-level manipulation of the ponds were discontinued. Over the years, the shooting ponds became valuable wetland habitat with natural vegetation. These wetlands were chosen as a demonstration site to study long-term sedimentation patterns in wetlands constructed in the fluctuation zone of reservoirs. Nineteen sediment cores were collected from eight different wetland areas. Sediment accumulation in the wetlands was determined by Cs(137) analysis of the cores. The cores were also sampled for bulk density, percent moisture, organic content, and grain size. Analysis showed that the wetlands were accreting 0.49 cm/year of sediments and accumulating 4.35 kg/m2/year of sediments. The average bulk density of cores was 1.00 g/cm3. Average mineral content was 94 percent. Sediments were 98.2-percent fines by weight. No distinct patterns in sedimentation among weflands was apparent. It is thought that micro differences between the wetlands play a large role in determining sedimentation at this site.
显示更多 [+] 显示较少 [-]