Lakes Planning Report. PUB-SS-1013 2005. A sediment core each was collected from the deep area of Mercer Lake and the northern basin of Grand Portage(Tank) Lake on 9 July 2003. The cores were dated by the 210Pb method and the CRS model used to estimate dates andsedimentation rate. The diatom community was analyzed to assess changes in nutrient levelsand changes in the macrophyte community and geochemical elements were examined todetermine the causes of changes in the water quality and changes in oxygen conditions in thebottom waters.

The Mercer Lake Association is sponoring a project which will complete a sediment core analysis to address existing water quality questions and assist in future planning efforts. The project includes a detailed core analysis on Mercer Lake and a less detailed, pre and post development analysis on Grand Portage Lake. Deliverables include: a written report detailing water quality changes found in both cores and an analysis of the significance of findings. This report will be shared with the public via press releases to surrounding communities, archived at the local library and presentation at the Mercer Lake Association annual meeting. This report will be provided to the Department in electronic (pdf) and hard copy format. ***Please note that approval of the final report for final payment by the Lake Grant Program does not indicate Department approval of recommendations or strategies within the report. **Paul Garrison, DNR Research, will handle SLOH costs associated with this project via individual contract with the SLOH and with the Mercer Lake Association.

Final Report