ABSTRACT:
Recent sediment deposition rates were investigated using cesium-137 dating techniques in a 950-ha (2,350-acre) area of Grassy Island wetland. The wetland is on the eastern shore of Reelfoot Lake in northwestern Tennessee. The forested wetland traps sediment transported by Reelfoot Creek from 31,000 ha (76,600 acres) of easily eroded ioess bluff hills and uplands, of which 16,000 ha (39,500 acres) were cropland. Sediment deposition in the study area amounted to 3 million Mg (3.3 million tons) in the 21-year period from 1964 to 1985. Average sediment deposition rates were high, with 2.6 cm/yr (1.0 inch/year) in the area where silt sediment was accumulating and 1.3 cm/yr (0.5 inch/year) in the remaining study area. Deposition rates coincided with estimated high erosion rates from cropland on the watershed, but only about 21% of the erosion from cropland was accounted for in sediment deposition. The capacity of the wetland to trap sediment, though considerable, was limited in comparison to soil erosion from steep cropland where no conservation measures were used.
Footnotes
Sherwood C. McIntyre is an ecologist and James W. Naney is a geologist at the Water Quality and Watershed Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Durant, Oklahoma 74702. This research was conducted under a cooperative agreement with the Tennessee Department of Health and Environment, Division of Water Management.
- Copyright 1991 by the Soil and Water Conservation Society
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
