New London Dam Reconstruction
Kandiyohi County, Minnesota
The New London Dam is the farthest upstream impoundment on the Middle Fork of the Crow River and creates a 2,516-acre upstream pool. Downstream of the dam, the river continues through Nest Lake, Green Lake and Calhoun Lake en route to the confluence with the North Fork of the Crow River near Manannah, Minnesota
The dam is over 100 years old and, prior to reconstruction, was unable to safely pass large floods. It also had seepage problems, and a problematic gate system. In 2008 engineering studies were conducted which determined that modifications and repairs were needed to bring the structure into compliance with current dam safety engineering standards.
The Minnesota DNR retained Stanley Consultants, Inc. from Minneapolis to provide engineering services for project. In 2009, final plans and specifications were prepared for the reconstruction of the dam. Key new project features included:
- A labyrinth spillway to replace the existing gated system which was outdated and problematic.
- A triple box culvert to pass water flows beneath 1st Avenue Southwest.
- A baffled chute spillway to dissipate water energy.
- Architectural concrete stone finish to selected walls and surfaces. The City of New London raised money to pay for the entire cost of the architectural concrete.
In early 2010, the project was advertised for construction and Lunda Construction Co., based out of Black River Falls, Wisconsin, was the successful low bidder with a bid of $2,615,000.
Reconstruction of the dam began in May of 2010, and was nearly complete at the end of November, 2010. On Monday, November 27, 2010, the upstream cofferdam was removed and river flows were directed through the new dam for the first time.
The project is 100% complete and final payment was made to Lunda Construction in December, 2011. MN DNR and the City of New London worked together successfully to complete this project. In 2012 Stanley Consultants Inc. and the Minnesota DNR were awarded a "Grand Award" for the project by the American Council of Engineering Companies of Minnesota.