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Rapid Landfill Assessment

Background


Prior to the establishment of the State and Federal PinelandsLandfill in the Pinelands protection standards, more than 60 sanitary landfills operated in the million-acre Pinelands Area.  With only one exception, all of these facilities ceased operations in compliance with the Pinelands Comprehensive Management Plan (CMP) and at the direction of the New Jersey Department of Environmental Protection (NJDEP). The Cape May County Municipal Utilities Authority’s Landfill, located in Woodbine Borough, is the only exception to the CMP's landfill closure directive. It currently operates under NJDEP oversight and is equipped with leachate collection, landfill gas collection, and impermeable capping systems.

The CMP requires that all landfills that ceased operation on or after September 23, 1980 that are located in the Preservation Area, and those that ceased operations on or after January 14, 1981 and are located in the Protection Area, must be capped with an impermeable material unless it can be clearly demonstrated that:


1. The landfill accepted only vegetative waste or construction debris for disposal;

2. An alternative means of addressing the public health and ecological risks associated with the landfill is available that will afford an equivalent level or protection of the resources of the Pinelands than would be provided if the landfill were capped with an impermeable material;

3. No leachate plume associated with the landfill exists and the landfill is not generating leachate; and

4. A leachate plume associated with the landfill exists, but poses no significant ecological risk to wetlands.

The Commission's requirement to impermeably cap inoperable landfills aims to minimize contamination of wells, wetlands and surface waters with landfill leachate; the noxious liquid produced as precipitation percolates through waste materials deposited in a landfill. Unfortunately, the lack of funding to properly cap landfills in the Pinelands has resulted in very few being closed in accordance with the standards of the CMP.

In 2012, the Pinelands Commission contracted with the United States Geological Survey (USGS), New Jersey Water Science Center to develop a screening tool to model the potential for landfill leachate to contaminate wells, wetlands or surface water bodies in proximity to the landfills based upon existing groundwater monitoring data that had been collected in accordance with New Jersey Pollutant Discharge Elimination System (NJPDES) permits issued to landfill owners.

The goal of the project was to rapidly assess and rank the relative cause for concern at each landfill using GIS mapping and solute transport modeling and to estimate contaminant concentrations at potential leachate receptors, identified for this study as 1. Developed areas likely to contain wells, 2. Freshwater wetlands and 3. Surface water bodies.

Screening Tool to Evaluate the Vulnerability of Down-gradient Receptors to Groundwater Contaminates from Uncapped Landfills

Completed in 2014, research hydrologists at the USGS' New Jersey Water Science Center developed the screening tool, which uses a modified spreadsheet version of the Quick Domenico Multi-scenario (QDM) solute transport model to estimate concentrations of contaminants reaching receptors under steady-state conditions. The screening tool uses the QDM results to categorize landfills as having high, moderate and low levels of concern based on concentrations reaching receptors relative to regulatory standards.

The Quick Domenico Multi-scenario solute transport model is described in two PowerPoint presentations: 

1. Screening Level Assessment of Uncapped Landfills in the Pinelands Area -- June 2014


2. Screening Tool to Evaluate the Vulnerability of Down-gradient Receptors to Groundwater Contaminants from Uncapped Landfills -- October 2014

Important attributes of the model: 

- Allows use of existing (historic and contemporaneous) groundwater monitoring well data collected pursuant to existing program (NJPDES) monitoring requirements, eliminating the need for new wells and additional analyses.

- Uses existing GIS data layers to identify the location of landfill boundaries, wetlands, surface water bodies and potential sites of drinking water wells, eliminating the need for ground level surveys.

- Runs as a spreadsheet application to provide ease of use with limited need for data inputs and parameter-value requirements.

- Domenico-based models are supported by the U.S. Environmental Protection Agency where contaminant transport is advection-dominated and not dispersion-dominated as is applicable to the highly permeable porous media that comprises the Kirkwood-Cohansey aquifer.

- Model inputs for landfill geometry, aquifer hydrologic and geochemical properties, and leachate constituent concentrations can be modified by the user based upon newly acquired data and site-specific analysis.

- The Commission staff has summarized and categorized the level of concern attributable to each of the Pinelands Area landfills for which monitoring well data was available from NJDEP.

The summary table can be accessed here.

Out of an abundance of caution, a high level of concern was attributed to Pinelands Area landfills for which no data was available at NJDEP.

In 2015, the Commission advised those municipalities in which a landfill with a high or moderate level of concern is located of the results of the USGS' screening level assessment, for local follow-up. These municipalities were encouraged to work with their local/county health officials to first determine if areas identified with high or moderate levels of concern for drinking water wells are served by onsite wells or are instead served by public water systems. The GIS coverages used in the screening level assessment do not differentiate between onsite and public water systems.

If it is determined that drinking water wells are present, the local/county officials would be encouraged to take action to ensure that the owners of such wells are appropriately notified so that they might have their wells tested for constituents recommended by NJDEP or the local health department.

With respect to ecological concerns, where a landfill with a "high" or "moderate" level of concern was identified based upon NJDEP landfill monitoring well data and the USGS landfill screening tool, Commission staff have asked that municipal officials meet with Commission staff to pursue site-specific studies to determine if remedial action is necessary to abate the potential for ecological impacts.

For more information about the rapid landfill assessment, please contact Environmental Technologies Coordinator Ed Wengrowski at (609) 894-7300 or ed.wengrowski@pinelands.nj.gov.