SESI Learning Series: Historic Fill - Overcoming the Challenge to Land Development
July 24, 2014
Historic Fill (HF) is often encountered on development projects in New Jersey. Historic Fill, by NJDEP definition, is nonnative material, deposited to raise grades, that was contaminated prior to placement, and is not connected with the operations of the site on which it is found. A Municipal Solid Waste landfill, as an exception, is not considered Historic Fill.
The NJDEP's "Historic Fill Material Technical Guidance" (the Guidance) published in April 2013, defines what must be done when Historic Fill is suspected.
If HF is suspected, the first step the investigator (a term used by NJDEP to describe anyone using the Guidance to remediate a contaminated site on behalf of a remediating party, including the remediating party itself) must take is to evaluate whether, indeed, HF is present. This can be done by way of a Preliminary Assessment and Site Investigation in accordance with the Technical Requirements for Site Remediation (Tech Req's/NJAC 7:26E).
It is notable that the Site Remediation Reform Act (SRRA) exempts the Licensed Site Remediation Professional (LSRP) from having to contact the NJDEP Hotline upon the determination that HF is present (NJSA 58:10C16k). In other words, it is not a reportable discharge; however, the person responsible for conducting the remediation must still investigate and remediate the HF in accordance with the Tech Req's and the Guidance.
The Guidance provides the remediating party the option of assuming that the suspected HF is contaminated above the applicable Soil Remediation Standards (NJAC 7:26D4.) There is no need to delineate the contaminants in this case, but rather, simply delineate the extent of the HF. This delineation can be completed with a few test pits and bore holes and does not require analytical testing. Then, a presumptive remedy of engineering controls (capping), institutional controls (deed notice), and biennial inspections may be implemented. The cost of the cap and associated biennial inspections can be readily calculated and included in a project's proforma.
The Guidance also details how to delineate and characterize the HF to determine if the soil is not contaminated above the applicable standards, in which case no remedy is required. Additionally, if contamination is found, surgical excavations can be completed and the soil would not require further remediation.
Groundwater below the suspected HF must also be addressed. The Guidance provides similar options in that it can be assumed to be contaminated, in which case a Classification Exception Area (CEA) must be designated and filed. Optionally, the Guidance defines the investigation needed to prove that groundwater is not contaminated.
Thus, the Guidance is a valuable tool for determining the impact of HF by defining the necessary investigative steps, and eliminating much of the uncertainty regarding the potential cost of remediation.
For information contact: Fuad Dahan, PhD, PE, LSRP at (973) 8089050
*Based on guidelines as of 7/24/2014