Old Shepard Street Dam
Canton, MA
SA designed repairs, secured permits, and administered bidding and construction of Old Shepard Street Dam to replace spillway concrete and improve overtopping resistance in the 100-year design flood.
SA inspected, evaluated, and designed repairs to this 450-ft. long embankment dam that includes a concrete spillway built integrally with a bridge carrying Old Shepard Street over Massapoag Brook, and has a height of about 11 ft. The Dam releases through the spillway into Massapoag Brook. The impoundment has a second release; a diversion channel near the pond inlet that bypasses the Dam and continues under Messinger Street, ultimately leading to Bolivar Pond. The Dam previously controlled water for mill power, however it is now used primarily for recreation.
The Project goals were to reduce risk of Dam failure and associated upstream and downstream impacts (i.e. improve Dam safety), to address deficiencies and requirements of Massachusetts Dam Safety Regulations, to repair and maintain the Dam, and to manage cost outlay to the Town.
SA performed subsurface explorations, dewatered inspection, concrete laboratory testing, evaluated subsurface seepage by finite element modeling, evaluated embankment and spillway stability, designed the replacement spillway piers and abutments, prepared design drawings, an operation and maintenance manual, contract documents, and permit applications for the repairs, and assisted the Town during meetings with abutters and stakeholders and project bidding.
The Project generally included replacing and repairing portions of spillway concrete; providing overtopping resistance by repaving Old Shepard Street, repairing the downstream stone masonry wall, armoring downstream slopes, removing trees and brush, and other maintenance and minor repairs. During construction, after removing vegetation to uncover the existing embankment downstream stone masonry wall that was to remain, SA and the Town concluded to rebuild the wall, including filtered drainage, to further improve its condition, and SA designed the new wall.
SA managed the Project during construction on Town’s behalf, observing construction for conformance with contract documents, performing concrete and soil materials testing, documenting construction and reporting to Massachusetts Department of Conservation and Recreation, Office of Dam Safety (MA DCR ODS) to meet MA DCR ODS dam regulations. SA administered the construction contract, reviewed contractor invoices, negotiated change orders, and managed contract close-out.