Project Description
site

Following are the steps most often required by the New York State Department of Environmental Conservation (NYSDEC) in the investigation and remediation of a former MGP site.

  • Remedial Investigation/Feasibility Study
  • Interim Remedial Measures
  • Record of Decision
  • Design and Construction

The Rockaway Park Site project is now in the Design and Construction Phase. The Design phase was completed in 2008 and the Construction Phase for the on-site area commenced in December 2008 and is scheduled for completion in late 2012.

Remedial investigation Summary:

  • Contaminants detected in soil and groundwater are consistent with those expected for a former MGP site (primarily the BTEX complex – Benzene, Toluene, Ethylbenzene and Xylene; PAH’s – polycyclic aromatic hydrocarbons; and cyanide compounds.
  • The contaminants associated with the site were observed to be migrating off-site in a northerly direction, under an adjacent public roadway and the bulkhead owned by the City of New York. The contaminants on the site in some locations have been found at depths 100 feet or more below the surface.
  • There are no data to suggest that the public is being exposed to the chemicals present in surface soil either on the site or in the community, although the potential for exposure – in both current and potential uses – exists absent remedial measures. There are also no data to suggest that the contaminants are having an adverse impact on fish or the transient wildlife in the community.

Interim Remedial Measures:

Prior to its acquisition by National Grid, KeySpan undertook Interim Remedial Measures (IRM) to minimize any current impact of the environmental conditions related to the historic use of the site.

  • Early in the project, KeySpan undertook a “cut-and-plug,” capping underground pipes that could act as conduits for the migration of contaminated groundwater or source material. 
  • During the relocation of the Long Island Power Authority (LIPA) electric substation on the site, some contaminated soils were removed.
  • An Interim Remedial Measure (IRM) has been conducted on the bulkhead area portion of the site, which is north of Beach Channel Drive and owned by the City of New York. This included removal of surface debris and tar-like materials on the surface.  Supplemental IRM activities also included additional removal of some subsurface contamination. Separately, in 2003, the City of New York repaired sections of the Bulkhead to address the “wear and tear” of years of constant exposure to the waves and winds of Jamaica Bay.
  • In addition to the IRMs, National Grid has completed the demolition of unused structures on the property, and the relocation of utilities in the areas where excavation or construction will take place.

Reports on the completed IRMs are available for review in the Document Repositories.

Record of Decision:

The Record of Decision describes the remedial goals and specific remedial requirements for the site to achieve those goals. For the Rockaway Park site the goals are to eliminate or reduce to the extent practicable the following:

  • Exposures of persons at or around the site to PAHs, BTEX and cyanide in soil, groundwater and soil gas vapors;
  • Environmental exposures of flora or fauna to PAHs, BTEX and cyanide in soil, groundwater, soil gas vapors and sediment;
  • The release of contaminants from soil into groundwater that may create exceedances of groundwater quality standards; and,
  • The release of contaminants from surface soil, subsurface soil, soil gas vapors, groundwater, and sediment into surface water, indoor air, ambient air, sediment, and soil gas vapors through storm water erosion, vaporization, wind borne dust and groundwater discharge.

Further, the remediation goals for the site include attaining to the extent practicable:

  • Ambient groundwater quality standards; and,
    photo
    Jet Grouting operations
  • Recommended soils cleanup values for surface soils.

The remedial requirements for the Rockaway Park site are:

  • Excavation of visible MGP tar to eight feet below ground surface (bgs);
  • Installation of on-site and off-site non-aqueous phase liquid (NAPL) migration barriers set at various depths;
  • Installation of passive dense non-aqueous phase liquid (DNAPL) recovery systems;
  • Installation of soil gas vapor control methods under any existing or new structures constructed on the site;
  • Installation of the Site-Wide Cap consisting of a demarcation fabric, clean soil, and crushed stone;
  • Development of a site management plan to address residual contamination and any use restrictions;
  • Imposition of an environmental easement; and,
  • Annual certification of the institutional and engineering controls.

Shallow Excavation activities commenced in December 2008 and were successfully completed in October 2010. In addition, approximately 80-percent of the Site-Wide Cap had been installed as of October 2010, with the balance to be completed after the 120 foot deep barrier wall is installed. In 2011, National Grid commenced the third phase in the installation of the on-site 120-foot-deep DNAPL Migration Barrier along the northern part of the site. The third phase is scheduled for completion in late spring 2012 and site restoration activities and then completion of the Site-Wide Cap is scheduled for completion in the summer of 2012.