Fighting rain, snow and slush in late March, a lake quality consultant and members of the Big Swan Improvement District’s TMDL (Total Maximum Daily Load) Committee took several core samples from the lake bottom. The sediment samples will help the LID identify causes of excessive phosphorus levels that the Minnesota Pollution Control Agency says affects our lake quality.
Steve Henry of RMB Environmental Laboratories, along with committee members Lee Daly and Jim Bieniek, took cores from five spots – three from the south basin and two from the smaller northern end of the lake at depths between 28 and 48 feet. They sank a weighted “torpedo” device with a long tube through ice holes into the lake bottom to collect several inches of sediment. The GPS-pinpointed samples will be analyzed for phosphorus at RMB in Detroit Lakes and mapped for a final report.
The LID committee also does ongoing inlet stream sampling. A certified lake consultant is doing an in-depth study of the inlet and core sampling, other RMB reports, the MPCA’s TMDL report and more available data to create an updated Lake Management plan. The committee is considering several treatment options including floating islands, aluminum sulfate application, additional inlet buffers and retention ponds.