Environmental Engineering Transforming Brownfields into Ballfields

Remediating former industrial sites provides opportunities for economic development by transforming areas of blight into recreational facilities, community centers, and mixed-use developments.

Rehabilitating brownfields such as this site transforms communities economically and socially. Source: D.N. Patton, Wikimedia Commons

According to the Environmental Protection Agency (EPA), there are more than 450,000 brownfield sites in the United States. These abandoned industrial sites are not only unsightly sources of blight in communities but they also often are contaminated with hazardous chemicals. The pollutants often pose a danger to people who venture onsite as well as to those living in nearby communities as the chemicals pollute the air and water supply. While remediating these sites so they are suitable for redevelopment is challenging, they offer significant financial, economic, social and community benefits.

The Advantages of Brownfield Remediation and Redevelopment

Some examples of the benefits of taking on the task of brownfield cleanup and redevelopment cited by the American Planning Association (APA) , the EPA, and the Sustainable Cities Institute include the following:

Once brownfield sites undergo remediation, they offer buildable parcels of land, which are often scarce in densely populated and developed urban areas.
As of March 1, 2016, the EPA’s brownfield development program created 108,924 jobs, a 32 to 57 percent decrease in vehicles miles in communities where industrial sites underwent remediation and development, and an increase between 5.1 and 12.8 percent in nearby residential property values.
Local governments realize an increase in their tax revenue when brownfield sites are redeveloped.
Redevelopment of brownfield sites provides the opportunity to showcase sustainable building practices including, but not limited to, of carbon footprint reduction, waste reduction, conservation of natural resources, and preservation of valuable and fragile ecosystems.

While brownfield remediation and redevelopment offers a number of financial, economic, neighborhood, and local governments numerous benefits, successful completion of these projects require a high degree of collaboration and attention to detail.

The Process of Brownfield Site Redevelopment

In order to facilitate projects involving brownfield remediation and rehabilitation, the APA, the EPA, and Sustainable Cities Institute recommend the following six-step process for brownfield remediation projects:

Develop a mutual vision agreement among potential stakeholders for the brownfield development project. While communities tend to like the idea of cleaning up former industrial sites, some stakeholders also tend to question the redevelopment of such sites. To address these concerns, as well as worries about the gentrification of surrounding neighborhoods, developers and engineering firms exploring brownfield redevelopment projects usually hold charrettes with private, public, and government interests. In addition to educating community leaders about brownfield redevelopment, collaborative meetings address:

The need for flexibility in expectations about the scope and timeline of the project
Creating a vision for the project, as well as straightforward goals and objectives
Establish attainable and quantifiable success metrics
Gain an understanding of local residential and commercial real estate markets to evaluate the feasibility of various redevelopment options
Design and implement a comprehensive communication plan to ensure all stakeholders are aware of the status of the project

Identify potential brownfield sites suitable for redevelopment. Based on the type of project envisioned during the charrette process, the developer and the engineering tea, explore the different brownfield sites to pinpoint those suitable for the project. Since many former industrial sites have sat abandoned for years, if not decades, public records concerning the site may be out of date, so the team may need to conduct a great deal of research when performing due diligence.

Conduct a thorough environmental assessment of brownfield site identified for potential redevelopment. In addition to following the EPA guidelines and policies for brownfield remediation, the development team also need to ensure they comply with all state and local requirements for the cleanup of industrial sites. A comprehensive environmental evaluation identifies the nature and level of any contamination. This assessment not only helps decision-makers judge whether the project is viable environmentally but also provides insight into the regulatory hurdles associated with redeveloping the property.

Determine the possible reuse options for the remediated brownfield site. Once the Federal, state, and local regulations for the parcels are known, the next step in the process is determining the types of projects that lenders will be willing to finance. Often banks are reluctant to lend funds for brownfield redevelopment due to possible delays due to regulatory inspections and the potential liability associated with these projects.

The APA recommends securing one or more of the following documents to ease the concerns of lenders and/or investors:

No Further Action Letter, which is issued either by the state or EPA
Certificates of Completion, which are typically issued by the state environmental authorities
Covenant Not to Sue, which is usually issued by the state government

As with any contract involving a potential liability issue, property owners and developers need to have an environmental attorney experienced with brownfield redevelopment issues, or a commercial professional liability insurance professional, to review any contracts or government documentation issued in order to decrease the level of risk associated with the project.

Review the cleanup options suitable for the site. Depending upon the intended use of the brownfield site and the nature of contamination, developers may have a variety of options available to them for site remediation. Some of the factors considered when developing a site cleanup plan include the following:

The technology and cost associated with various remediation methods
The role of the surrounding community in the decision-making process
The extent to which liability can be minimized
The need to involve technical consultants with a particular level of expertise

Once the cleanup plan receives approval from regulatory agencies, the remediation of the brownfield site starts. When establishing a timeline for the project, ensure to account for potential delays for periodic inspections.

Launch the site redevelopment plan. Once the brownfield is clear of all toxins and pollutant and passes inspection, the construction of the redevelopment can begin.

While brownfield redevelopment is more time -consuming and complex than the development of non-contaminated sites, it offers the opportunity for innovation. In addition, rehabilitating former industrial sites opens new space for construction in dense urban areas.

Case Study: The Regency Athletic Center at Metropolitan State University Denver

Located in downtown Denver, the administration of the Metropolitan State University (MSU) faced a challenge when they wanted to build a new athletic complex – the only open site near the urban campus was a former industrial site. An environmental assessment of the 13-acre parcel found soil contaminated with multiple hazardous substances, including lead, tar, and asbestos, as well as a polluted groundwater plume. When university officials consulted with a local engineering firm about cleaning up the brownfield site, the initial $ 3 million estimate made the project cost-prohibitive.

The engineering firm based their estimate on the use of traditional remediation practices involving excavation of the contaminated soil, which was 15 feet deep in places, hauling and disposing of the toxic material, and replacing the removed fill. Another problem with using this process was that it would be time-consuming, which made completing the project within the seven-month deadline impossible. Fortunately, the engineering team proposed an alternative method to rehabilitate the site – deep dynamic compaction.

The Use of Deep Dynamic Compaction in Brownfield Redevelopment

The deep dynamic compaction process (PDF) recommended by the engineers involved dropping a steel ball, weighing 30 tons, from a 100-foot-tall crane. The onsite team would lay out a grid with 10-foot squares and then drop the ball seven times in one area, creating a five-foot-deep crater, before moving to the next section of the grid. Using this process, the engineers reported 80 sections of the grid could be completed each day, meaning the first pass would take three months. The second pass would involve compacting soil located in areas off the grid. The final pass would involve using a lighter weight to tamp the fresh soil used to fill the crater. While this process was significantly less expensive than traditional soil remediation methods, it created a great deal of noise and vibration, as well as the risk of releasing toxins into the air. Despite these potential problems, MSU officials accepted the proposal and gave the go-ahead for the project.

During the deep dynamic compaction process, the engineers monitored the air quality and noise, as well as the amount of vibration, which registered within acceptable levels. Since the brownfield site was located a fair distance from other businesses, the work was not disruptive. Once site team completed the deep dynamic compaction process, they used geotechnical drilling to measure the amount of soil compaction. This process involved dropping a 140-pound hammer from a height of 30 inches into the soil. The engineers documented the number of blows required to penetrate the soil. They found twice as many blows were needed for penetration after deep dynamic compaction as were required prior to the remediation work.

The Efficacy and Benefits of Deep Dynamic Soil Compaction.

Once the engineering team completed the site work, regulators from the Colorado Department of Public Health and Environmental Voluntary Cleanup and Redevelopment Program assessed the site. The state officials approved the site and issued A No Further Action Letter, which allowed the construction of the $25 million Regency Athletic Center. The facility was completed on time and on budget.

Some of the advantages of using deep soil compaction outlined by the engineering firm include:

The process yielded a surface well-suited for the athletic center’s soccer, baseball, and softball fields, as well as the tennis courts.
The densely compacted soil will minimize settling issues with the complex’s buildings and sports fields and courts.
By using this remediation process, the team did not have to spend money on disposal of the contaminated soil.
The team was able to continue to work onsite during Denver’s wet and cold winter conditions.
The process transformed a large abandoned industrial site into a productive urban sports facility.

The engineering firm received Colorado’s top engineering award from the Colorado Council of Engineering Companies for the successful application of their innovative approach to brownfield redevelopment.

Has your firm taken on the challenge of brownfield redevelopment? If so, what was your experience?