Occidental Chemical Company constructed a groundwater barrier wall around the S-Area at its Niagara Falls plant. Occidental engaged Herbert F. Darling, Inc. to construct the barrier. McMahon & Mann served the project contractor as its engineer providing design and construction recommendations. McMahon & Mann worked with the contractor to develop an alternative concept when it was discovered that the specified traditional cutoff wall design could not be constructed. Shot-rock fill extends to bedrock along the Niagara River section of the cutoff wall preventing construction of a soil bentonite wall using the conventional slurry trench approach. The barrier wall was constructed in an open excavation using two rows of sheet piling as support for the soil-bentonite mixture.

McMahon & Mann served as the project quality control engineer during construction and in that role was responsible for all field and laboratory tests on the trench, bentonite slurry and soil-bentonite backfill. We also coordinated with the various regulatory agencies overseeing the project including the NYSDEC, the US Environmental Protection Agency, and the City of Niagara Falls.