As part of the Living With The Bay Program, Governor’s Office of Storm Recovery (GOSR) identified over thirty (30) stormwater resiliency related improvements projects throughout the Mill River Watershed in Nassau County, NY. The Smith Pond Rehabilitation project is one of the more significant of these projects. Smith Pond, originally named “DeMott’s Pond” after the local DeMott’s Mill that was located on the pond, is part of the tributary system in the Mill River Watershed located in the Village of Rockville Centre, located downstream of Hempstead Lake. The existing pond water surface elevation is controlled by a weir which discharges downstream flow into a channel and a series of culverts that run underneath Merrick Road and NY Route 27 Sunrise Highway to Mill River. This entire region was heavily impacted by the Superstorm Sandy in 2012.
In an effort to address flood/storm resiliency issues, improve the ecology of this ecosystem, and improve user access to the pond for recreation, a number of improvements were specified as part of this project, including construction of a fish ladder, a new greenway/trail paralleling the pond, two (2) new flood walls, improvements to the weir, replacement of deteriorated timber bulkheads, installation of new trailway lighting, and replacement of existing asphalt pavement parking lots with porous pavement.
The improvements project required the existing weir to be evaluated. Hayduk Engineering and a team of diver inspectors and structural engineers evaluated the condition of the existing weir. The weir is comprised of a reinforced concrete weir cap, timber walers, timber sheet piling, a concrete channel, and a drainage structure which allows for the pond to be drained. The evaluation resulted in the recommendation of improvements to the timber sheet piling. The Hayduk Engineering team designed a reinforced concrete encasement system that is expected to extend the lifespan of the weir for decades. Hayduk Engineering also evaluated the condition of the existing bulkheads surrounding the weir, which resulted in the engineering design of the replacement of the failing timber bulkheads with new cast in place concrete bulkheads. Hayduk Engineering was also responsible for the engineering design of the new trailway bollard-style lighting system and the infrastructure for a future closed circuit television security system to be installed at a later date.