Lake Zumbro was formed in 1919 following construction of the Lake Zumbro hydropower dam. Located just six miles north of Rochester, Minnesota, the lake covers 650 acres and is five miles long. It also has the highest population relative to recreational lake area within greater Minnesota. Over time, increased sediment deposition has decreased lake water volume from 18,000 acre-feet in 1919 to 10,000 acre-feet in 2005. In 2006, Lake Zumbro Forever, Inc. (a nonprofit corporation dedicated to restoring the lake) hired Barr to conduct a feasibility study for dredging portions of the lake to restore recreational access. We collected lake bathymetry data to assess sediment accumulation over time. We also sampled and tested sediment to determine if contaminants were present and conducted sediment probing to estimate sediment locations and volume. We then developed a strategy and cost estimate for removing sediment in targeted locations and supported location selection and design of an upland sediment-disposal facility.
In 2009, Barr was retained to prepare the preliminary engineering study to advance lake restoration and dredging further. For more than a decade, Lake Zumbro Forever, Inc. aligned partners and raised funds for the project. Once funding was secured, the Olmsted-Wabasha Lake Zumbro Joint Powers Board hired Barr for final design, plans and specifications preparation, and construction services.
The Minnesota Pollution Control Agency, Minnesota Department of Natural Resources, and U.S. Army Corps of Engineers worked together intermittently for nearly 10 years to identify regulatory concerns and define a permitting strategy. Barr successfully completed an environmental assessment worksheet and secured all environmental permits to allow the project to move forward to construction, which began in fall 2018. All dredging was completed during the fall of 2019.