The Challenge

Contaminated river water plagued Union Lake and its dam for decades. Chemicals that had regularly been released into the water began to take their toll on the Union Lake in the 1980s, prompting dam owners to consider constructing of a new one. This new dam would be a vast upgrade from the old model, which was composed entirely of stone masonry, and its construction would include working extensively with concrete in hazardous environments. It would also require a mechanism for holding water in check throughout the process of construction.

The Solution

The Conti Group displayed its ability to handle all of these tasks while developing methods to combat the unique challenges of the project. Complete demolition and removal of the old dam was made possible by the construction of an 85,000 cy earthen cofferdam upstream in the lake and downstream across the river. To safely excavate and remove the hazardous chemicals from the old dam site, Conti installed an extensive well point and deep well dewatering system around the perimeter of the cofferdam to lower the groundwater in the foundation excavation area for the new dam.

These techniques proved to be extremely effective, as Conti was awarded the Merit Award for Cast-In-Place by the American Concrete Institute. Conti built a replica of the original stone masonry dam after project completion as a present for the town of Millville.

Scope of Work