Roux Associates was commissioned to develop a sediment remediation plan for impacts to a 3.2-acre pond located in the Massapequa Preserve on Long Island, New York.  Upgradient of the pond is a former aircraft parts manufacturing and metal finishing facility that began operation in the late 1930’s.  Investigation activities concluded that contaminated groundwater emanating from the facility led to deposition of cadmium and chromium in the pond sediments. 

Remediation activities included the removal of impacted sediment from the pond, followed by the installation of replacement wetland substrate and restoration with native emergent wetland plantings.  The various elements of the Site remedial activities included the following:

  • Wetland protection, erosion control and vegetation clearing;
  • Pond dewatering and storm water bypass;
  • Excavation of contaminated sediments;
  • Sediment dewatering and stabilization of excavated sediment; and
  • Off-Site disposal of contaminated sediment.

Following the excavation of sediment and final grading of the pond bottom, designated marsh areas were backfilled with a high organic carbon content substrate and restored with a diverse array of native emergent wetland species.  Disturbances to wetland resource areas were mitigated via in-place restoration of the wetlands and adjacent areas at a 1:1 ratio. 

The ultimate goal of the mitigation plan was to maintain the primary function of the pond as a storm water detention unit, and replace the former pond marsh with a structurally complex emergent low marsh surrounded by a shrub/forested adjacent area. 

Remediation and restoration of the pond and wetlands were completed in 2008.