The Red House Lake Dam is located in Allegany State Park in the Town of Red House, Cattaraugus County, New York. The dam and arched bridge were built across Red House Brook in 1929 to create a recreational lake for the park. According to the New York State Inventory of Dams, the dam has a hazard classification of B (Intermediate Hazard dam). The dam consists of earthen embankments (total length of 1,350 ft.) and a concrete spillway with a length of 180 feet. Allegany State Park Route 1 runs along the dam crest and over a three-span bridge built on the spillway section.

McMahon & Mann completed a subsurface exploration program, and prepared an Engineering Assessment Report with Bergmann. The report included the results of a safety inspection, hydrologic and hydraulic analyses, stability and seepage analyses and identified deficiencies in the dam. The report presented conceptual recommendations for remediation to bring the dam into compliance with current NYSDEC Guidelines. The team also prepared design drawings and specifications for dam and bridge rehabilitation improvements.

McMahon & Mann provided part-time construction monitoring services, during the rehabilitation work. Rehabilitation work included installment of 22 rock anchors in three different bays at the downstream toe of the spillway, stump and vegetation removal, flattening the downstream slope of the embankment by adding approximately 13,570 cubic yards of fill, flattening the upstream slope of the embankment, clearing and grubbing the existing slope above the normal pool water level, and placing stone fill and bedding materials to armor the slope.

McMahon & Mann also reviewed and responded to geotechnical engineering related contractor submittals, and attended pre-bid, pre-construction, and construction progress meetings. McMahon & Mann observed the downstream slope improvements, piezometer extensions, and retaining wall construction. Construction was completed in August 2018.