Greg Farrell’s technical professional expertise is in civil and environmental engineering for commercial and industrial clients.

He focuses on contaminated site assessment, characterization, and remediation; cell design and construction management assistance in surface mine dewatering; expansion of solid waste management facilities; and special projects, such as the design of a containment system around a sinkhole in a marsh.

He is the Engineer of Record for a sinkhole containment system design and construction project for the Texas Brine Company in Assumption Parish, Louisiana. His roles include technical engineering, project management, operations management, and project management training and development.


What are the current trends in site assessment, characterization, and remediation?

Work in this field has been around for a while, but grew tremendously in the 1980s when the Resource Conservation and Recovery Act hazardous waste regulations and Superfund were born. In the early years, after the onset of those regulations, it took a while for the regulatory, business, and consulting communities to get their heads around how to adequately address all of the issues surrounding these contaminated sites—especially since many of the companies that created those sites were no longer in business. For the companies that were still in business, many did not have an environmental staff that knew the requirements. Fast-forward about 30 years to today and we have advanced quite a bit from the early days of the remediation industry. We have gone through many phases. At one time it seemed like the solution for every site was to dig up all the contaminated material and incinerate it—that didn’t last too long!

Today, our clients are very knowledgeable about environmental regulations and the site characterization and remediation process. Often times we have much more of a partnering relationship with our clients than in the past due to their knowledge of the state of the remediation industry.

What is the greatest challenge in your field today?

Probably to continue to find ways to do it better, quicker, and for less cost. One very valuable resource available to us here at Tetra Tech is the Remediation Strategies Team, which is a network of Tetra Tech professionals with experience in many different aspects of site investigation and remediation. If an employee has a need for specialized assistance—such as a specific contaminant that is present in water, groundwater, soil, or air with any other extenuating circumstance—they can simply send an email to the group and soon their inbox will start filling with responses from professionals within Tetra Tech. I am always amazed at the many talented folks working at Tetra Tech and the vast body of project experience that we collectively have across the company.

How do regional differences affect practices in your field?

I work primarily in the U.S., but even so, I have noticed that regional and state differences impact the projects that I work on. Probably the most obvious are the differences in the state regulatory agencies and their regulatory structures. When you first work on a new project in a state that you haven’t worked in previously, there is typically a steep learning curve to become familiar with the regulations and the agency personnel that you will be dealing with.

Also, since site contamination and subsequent remediation work is very much impacted and influenced by the topography, geology, and hydrogeology in the area of the site, I have found that the region where a site is located in impacts the way that work is performed at that site. This provides an opportunity to challenge ourselves and expand our knowledge, something that in the long run is rewarding.

What has been an interesting or challenging subsidence project in which you’ve been involved?

I am currently working on a project for the Texas Brine Company Sinkhole project in Louisiana that involves the design and construction of a containment system around a very large sinkhole, which is underwater, as it is located in a marsh. One of the effects of the sinkhole formation was the release of naturally occurring oil and other contaminants into the sinkhole waters. As those materials rise to the surface, they pose a danger of being released into the surrounding marsh areas, including nearby residential areas that are built in the marsh. Working with Tetra Tech professionals from many different offices and with different areas of expertise, we have been able to design and oversee the construction of a series of earthen levees that connect to completely encircle the sinkhole, so that the released contaminants are contained. This is an ongoing challenge, however, as the sinkhole continues to grow, and the area surrounding it has been experiencing significant subsidence.