T.Y. Lin International retained by the New York State Thruway Authority Canal Corp to develop plans and contract documents for the rehabilitation of Movable Dam 7. The dam consists of three spans, the outside spans are 186.5-foot steel trusses and the center span is 216.5-feet in length. The steel trusses support 19 vertical lift gates.
Constructed in 1914 with modifications added in 1924, the dam was deteriorated, requiring remediation of the structural steel superstructure and gates, as well as the substructure units and concrete aprons. The detailed inspection of the dam will consist of ultrasonic thickness measurements to determine the extent of steel deterioration, and concrete coring to establish the depth of concrete deterioration. After the inspection, structural analysis was performed to determine which elements of the dam would require replacement or remediation.
A Dam Safety Report is being developed for the project per the requirements of the NYDEC. In addition to the required structural repairs, the project also involved the preparation of a detailed Cofferdam Impact Analysis to determine the flooding impacts to the adjacent communities. A detailed HEC-RAS model was developed of the area and was also utilized for the Dam Safety Report. NYDEC requires that a Sunny Day Failure be investigated to determine the effects of a dam breach on downstream communities.
An investigation of hazardous waste and contaminated materials (HWCM), asbestos, lead, and the impacts to threatened and endangered species will be completed, as well. Barge mounted drilling rigs will be used to perform geotechnical investigations.