Wind-Induced Sediment Resuspension and Export in Marsh Lake, Western Minnesota.
Abstract
Budgetary information and sediment resuspension dynamics were determined in Marsh Lake, located on the Minnesota River in western Minnesota. Resuspension and discharge of seston, particulate organic matter (POM), and total phosphorus (total P) were examined in Marsh Lake during June through September 1991 and May through September 1992. Based on a theoretical wave model, lakebed sediments at water sampling stations in Marsh Lake were susceptible to sediment resuspension at wind velocities as low as 10.5 km/h, depending on wind direction. Mean daily wind speeds were> 10 km/h on over 40 percent of the days during both study years, suggesting a strong potential for frequent sediment resuspension at these stations. Measured resuspension of seston, POM, and total P was much lower in Marsh Lake in 1991 than in 1992 as an apparent result of dense aquatic macrophyte beds that in 1991 covered nearly the entire lake. In 1992, when aquatic vegetation was absent from Marsh Lake, seston, POM, and total P concentrations increased substantially in the water column as a result of sediment resuspension. The discharge of high concentrations of resuspended sediment and associated constituents from Marsh Lake occurred primarily when strong winds were blowing from the northwest toward the outlet weir of Marsh Lake. The critical wind velocity for the discharge of resuspended seston, POM, and total P was 20 km/h in 1991, when aquatic plants were present, and only 12 km/h in 1992, when aquatic plants were absent. Thus, discharge of resuspended sediment occurred only 2 percent of the time in 1991 and 15 percent of the time in 1992. The results of these studies were used to critically evaluate management alternatives for habitat and water quality improvements in Marsh Lake.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1995
- Accession Number
- ADA301385
Entities
People
- John W. Barko
- William F. James