Brownfield Post-Development Site Management

Photo Source: Tennessee Department of Environment & Conservation

​Long-Term Management and Maintenance

Property management of a Brownfield may continue after redevelopment is considered complete.  Management involves a number of tasks to ensure the long-term sustainable reuse of the property. This includes managing the financial aspects, physical plant, community relations, and any long-term environmental issues associated with the property.

Long Term Operations and Maintenance of Remedial Systems

Some remedial methods, such as ground water pump and treat systems, require long-term operation and maintenance.  In these instances, the property owner may be responsible for submitting monitoring reports to the agency with regulatory oversight on a periodic schedule. In addition, many Brownfield properties incorporate engineering and institutional controls in their remedial plans to restrict property access or use.  Engineering controls such as asphalt caps and fencing should be inspected on a regular basis to ensure they remain protective of human health and the environment. Institutional controls often take the form of deed restrictions or easements. Property owners must maintain awareness of these restrictions and ensure they transfer to the new owner if the property is sold.

Stewardship Obligations for Institutional and Engineering Controls

Under certain circumstances, containments above regulatory standards are left in place at Brownfield sites. Generally, this occurs when the contaminants are at low levels, are generally spread throughout the media and do not present a risk to human health or the environment when properly contained. For example, large portions of New Jersey and other urban states in Geographic Zone 1 are covered by historic fill. This non-indigenous material, deposited to raise the topographic elevation of the site, was contaminated prior to emplacement, and is not connected with the operations at the location of emplacement. Historic fill includes construction debris, dredge spoils, incinerator residue, demolition debris, fly ash, or non-hazardous solid waste. Typically historic fill contains PAHs and metals above residential standards, but these compounds are not migrating and do not pose a threat to groundwater. Under this circumstance, a cap is used to prevent direct contact with the historic fill material and a notice is attached to the property deed informing future owners that contaminated material underlies the site. The cap is referred to as an engineering control and the deed notice is an institutional control.

Engineering Controls

Engineering controls are any physical mechanism used to contain or stabilize contamination or ensure the effectiveness of a remedial action. Engineering controls may include, without limitation, caps, covers, dikes, trenches, leachate collection systems, signs, fences, physical access controls, ground water monitoring systems and ground water containment systems including, without limitation, slurry walls and ground water pumping systems.

The most common form of engineering control on Brownfield sites is a cap. This a surface placed over the impacted media that prevents direct contact and inhalation of air born particulates. Caps take several forms. They can be soil covers (usually 1 to 2 feet of “clean” soil), hard surfaces such as pavement or concrete, or landscaped areas. Caps require periodic inspections and maintenance.

Sometimes groundwater impacts are minimal and the contaminants are undergoing natural attenuation (i.e. biological degradation or dilution through advection). Under these circumstances, if groundwater is not used for drinking water and vapor intrusion is not a threat, than an acceptable remedial approach is monitored natural attenuation (MNA). The groundwater impacts are allowed to degrade over time. The rate of degradation is predicted using computer models and the concentrations of the contaminants is monitored over time. Actual concentrations are then compared to the model predictions to determine and evaluate the effectiveness of MNA. The groundwater monitoring system is considered an engineering control.

Institutional Controls

Institutional controls are mechanisms used to limit human activities at or near a contaminated site, or to ensure the effectiveness of the remedial action over time, when contaminants remain at a site at levels above the applicable remediation standard which would allow for the unrestricted use of the property.  Institutional controls may include structure, land, and natural resource use restrictions, well restriction areas, classification exception areas, deed notices, and declarations of environmental restrictions.

The most common form of institutional control is a deed notice. A deed notice provides notice to future property owners that contamination on the real property exists at a level above the applicable unrestricted use soil remediation standards and an engineering control has been applied to the property.

A type of institutional control for groundwater impacts is a well restriction. This control is used when groundwater impacts exceed the appropriate water quality standard and is allowed to remain in place. The area of impacted groundwater is mapped and a notice is filed with the environmental agency and water supply bureau that prevents any wells being installed in the restricted area until impacts deteriorate below standards.

Stewardship Organizations

Institutional and engineering controls are assigned to the property or “run with the land” and therefore are transferable to subsequent property owners. These controls can last for many years (for example in the case of caps, the operational lifetime may be 30 years or more). In order to track the performance of the engineering and institutional controls and keep a record of them, most states within Geographic Zone 1 have monitoring, maintenance and reporting requirements either on an annual or biannual basis. This means that for the duration of the engineering or institutional control, regular reports must be submitted by the property owner to the appropriate regulatory agency. Thus, on many Brownfield sites there can or will be a long term stewardship obligation of the Brownfield site property owner(s) to maintain and report on the engineering and institutional controls.

Reports need to be prepared by a professional and certify that institutional controls, such as a deed notice are properly maintained, that caps and other structures have not been compromised, that the remediation is still effective in its remedial action objectives, and that applicable criteria or standards have not become more restrictive. With regard to groundwater, the report should compare current concentration of COCs in groundwater against standards and previous sampling results and indicate that no wells have been installed in the restriction area.

Brownfield site owners should budget for the stewardship obligations. While these costs are not substantial (usually $5,000 to $10,000/year), over time they can add up. Additionally, transition documents should identify the stewardship obligation and transfer the costs to subsequent property owners.