Flood Mitigation

With increasingly dense development in the upland townships above the City of Rensselaer, flooding of the downtown area had become more frequent, especially in the Quackenderry Creek watershed. Weston & Sampson was asked to find a solution to reduce the incidence of flooding, resulting in a series of successful flood mitigation projects.

Weston & Sampson first developed a rainfall-runoff model of the Quackenderry Creek watershed, confirming its tendency to flash flood and identifying the most flood-prone tributaries. A flood retention dam structure was designed, permitted and constructed to impound flood waters and protect the residents. This structure was designed to take advantage of the existing bridge abutments for its structural strength, and it is credited with limiting the damage from a subsequent flood event.

Weston & Sampson also developed a detailed hydraulic model of the creek and identified at-risk public infrastructure that could be enlarged or protected to minimize flood damage. A hydraulic model was also used to identify flood-prone neighborhoods to target enforcement of restrictions on floodplain encroachment.

Immediately upstream of its confluence with the Hudson River, Quackenderry Creek runs underground beneath the Rensselaer rail station property. Due to a large storm event in 2008, the inlet of the conduit became obstructed and caused major flooding in the City and upstream areas. Weston & Sampson investigated the failure of the culvert, finding that the existing culvert was found to be six feet in diameter, which was smaller than the arched conduit feeding it; this inappropriate design allowed debris to become lodged and flow to be obstructed. The culvert was removed and replaced with an appropriate box culvert. A smooth transition collar was constructed to connect with the new box culvert. In addition, a retaining wall and rip rap bank protection was installed to stabilize the bank and stream flow.

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Posted in Climate Resilience, Resource Management.