North American developers and contractors are well aware of the high costs associated with transferring soil from developments. These costs only increase when some or all of that soil contains regulated contaminants such as petroleum hydrocarbons or metal concentrations. Due to past activity on properties, soil contaminants can test above safe background levels.
Keith Etchells discusses assessing and managing regulated waste soil and “clean” or inert soil to avoid additional expenses, risks, and delays when moving soil on your project is necessary. Using his expertise and California regulations as context, he covers the regulatory framework and legal requirements regarding proper soil transport and disposal, with best practices to avoid risk and liability.
Proper Planning – From Phase I ESA to Soil Sampling to Soil Management Plan
The California Water Code and Titles 23 and 27 of the California Code of Regulations are often interpreted to mean any soil with detectable concentrations of hazardous substances or metals above interpreted background levels as a “waste” upon excavation and export from a job site.
Based on the characterization of exported soil as waste, developers must discharge it to a waste management unit licensed and permitted for treatment or a disposal facility. These select facilities treat, store, dispose of, or reuse soils under appropriate local, state, and federal regulations.
Proactively and efficiently complying with regulations and minimizing the risks of improper disposal helps avoid project delays and uses a progressive assessment process. Assessment starts with completing a Phase I Environmental Site Assessment (ESA) report to identify the recognized environmental concerns (RECs) that may exist. Move to a second step if a Phase I ESA report indicates RECs or environmental concerns of possible soil impact.
What Constitutes Hazardous Waste?
Using soil sampling and analyses, complete a Phase II ESA. The findings of the Phase II ESA may indicate the presence of soil impacts from chemical constituents such as petroleum hydrocarbons, solvents, and pesticides.
Additionally, naturally occurring metals such as arsenic can be elevated from regional geologic sources at levels that exceed regulatory screening levels and disposal standards. Are these hazardous wastes? That depends on the concentrations and elevations of the chemical constituents or metals in the soil. Properties with previous land use often show concentrations of these constituents below hazardous waste levels but high enough to designate certain soils as regulated “non-hazardous” waste. Dispose of or recycle this waste at a properly licensed facility.
Whether profiling waste soil for off-site disposal at a licensed receiving facility or characterizing the extent and composition of ”clean” or inert soil for transportation to another nearby construction site that needs fill soil, guide the process and action using the soil sample collection and analyses for various constituents of concern. These are identified in the Phase I ESA report to facilitate approval for the various soil waste types at the appropriate disposal facilities.
Waste Profiling Data Requirements
Most landfill and treatment facility operators generally want waste profiling completed with no more than a year-old data. However, justifications can be made for using older data if it demonstrates that the soil samples still represent current site conditions. Proper design and completion of soil sampling plans by qualified professionals should provide sufficient data to answer important questions:
If you need to move clean soil:
Minimizing Cost Overruns and Project Delays
Early characterization of contaminated and inert soil provides much more confidence in disposal cost ranges used in project planning. Characterization also helps determine the feasibility of disposal strategies to limit the exported amount of impacted soil. They minimize potential litigation associated with toxic tort and improper waste disposal practices.
While some contaminants may not be present in concentrations below applicable screening levels, any detectable chemical constituents or metals above background concentrations are regulated waste, which costs more to export. Facilitating better communication between the selected grading contractor and your trusted environmental consulting company facilitates earlier soil characterization. Waiting until grading starts to test soil can cause project delays and increase the cost of rushed laboratory analyses and unexpected additional disposal costs to meet construction schedule needs.
With the help of your environmental consultant and consultation with design and construction team members, you can employ value-added strategies to reduce soil disposal costs. When requiring soil export on a job, one strategy involving soil with relatively low levels of contaminants below human health risk screening criteria but still considered a regulated waste entails the preferential reuse or burial of that soil on site.
Soil Reuse – Savings and a Lower Carbon Footprint
Reuse typically results in significant savings since it allows the preferential disposal of inert soil as opposed to the costlier disposal of impacted soil. This can be completed if the limits of the impacted soil versus inert soil are adequately delineated through prior soil sampling and analysis, which provides the confidence of knowing which soils are inert and which soils are impacted when it comes time to grade and export soil.
A qualified environmental professional with a proven background servicing the construction sector will guide you through the nuances of applying the appropriate regulatory guidance. These professionals can design various strategies to reduce soil disposal costs, often covering the cost of soil sampling and analysis while providing additional risk management and liability protection to your project.
The Benefits of a Soil Management Plan
The Soil Management Plan covers all aspects of properly handling and managing waste soils during development. Your consultant works with your design and, or construction team to develop the feasibility of soil management strategies best engineered to reduce soil disposal costs.
During the grading process, the environmental professional oversees the Soil Management Plan during the movement of impacted soil to minimize environmental risks from improper disposal during grading. Improper disposal can result in costly fines or recourse from an import site. Your project professional and plan will minimize delays that would otherwise result from the discoveries during grading of previously unknown soil impacts, such as underground fuel tanks or previous dumping areas.
Environmental oversight during grading and having a soil management plan in place are often required with regulatory oversight, whether through voluntary oversight programs or when regulatory oversight is a condition of obtaining a grading permit.
Clean Soil Export Considerations
Exporting fill material from a previously listed contaminated site may require local Regional Water Quality Control Board approval in California. Failure to properly assess whether these requirements govern your site could lead to costly fines from your state. The receiving facility may also need Regional Board approval. In my experience, the land owner and contractor could face liability in both scenarios.
Documentation for Large Developments
SCS Engineers supports a large infill development project requiring more than a million cubic yards of clean fill to achieve the final grade. Using a project-specific environmental and geotechnical import specification, we’ve identified potential sources from nearby construction projects and supply facilities to meet import requirements. It details the number of soil samples and laboratory analyses based on design and regulatory standards.
Whether the export site provides soil sample analytical data or the cost of soil sampling an export site is taken on by our client, SCS reviews the soil analytical data before soil import for adherence to import specifications. A “Clean” or Inert Soil letter documents the vetting process and quality of the imported soil. The developer avoids the risk of project delays due to inadequate sources of clean soil available or increased costs associated with importing soil if finding an acceptable local clean fill source proves difficult.
The Fine Print – Additional Fees May Apply
For example, any generator site in California incurs hazardous waste generation and handling fees when disposing of five or more tons of hazardous waste soil within a calendar year. The current rate is $49.25 per ton. The state requires that generators maintain waste manifests for each truckload of exported soil and weight tickets associated with any hazardous waste disposal so it can register and report hazardous waste disposal quantities to the California Department of Tax and Fee Administration. Failure to register and pay these state fees results in auditing and significant penalty fees. The generator will often need a temporary Environmental Protection Agency identification number.
Environmental planning for developers is often a complex undertaking. We hope this article and its explanation of soil transfer details from an environmental professional will help keep your project on time and within budget.
About the Author: Keith Etchells is a professional geologist and hydrogeologist with over two decades of experience assisting clients in managing environmental risks associated with the ownership, transfer, or operation of commercial, industrial, and waste disposal properties. Contact Keith if you have questions about soil remediation on LinkedIn or the SCS Professionals Directory.
Additional Remediation and Planning Resources:
COMM22, a master-planned, mixed-use development project on a former brownfield, receives the 2023 Phoenix Award as an outstanding development on a revitalized property. The national premier awards program for brownfield redevelopment reflects the progression of brownfield redevelopment over decades and recognizes extraordinary practitioners and projects such as COMM22.
SCS Engineers will be at EPA’s Brownfields 2023 Conference to accept the award on behalf of the COMM22 team. The COMM22 development is the result of a collaboration between BRIDGE Housing and the Metropolitan Area Advisory Committee on Anti-Poverty (MAAC) in partnership with San Diego’s Unified School District as a public-private partnership.
“The COMM22 team is honored by the Phoenix Award. Many partners are part of transforming this once-underutilized school district site into transit-oriented affordable housing connecting people to jobs and services. I am pleased to thank them all. Our mission at BRIDGE Housing is to strengthen communities and improve the lives of our residents, beginning – but not ending with affordable housing. COMM22 is an excellent example of the collaboration and creativity required to address a housing crisis of the magnitude we are facing. On behalf of BRIDGE and the entire COMM22 team, it is my pleasure to extend our appreciation to the organizers of the Brownfields conference and the Phoenix Award.” said Jeff Williams, director of development for BRIDGE Housing.
The COMM22 team took an abandoned and contaminated property in a mixed residential and commercial neighborhood to create a thriving hub of residences reinvigorating the area and providing stable homes for hundreds of low-income individuals, elders, and families.
Brownfield revitalizations have grown substantially with public, private, and nonprofit practitioners nationwide who depend on brownfields as a strategic function of planning, economic development, environmental quality, and community development. The COMM22 project, for example, provides over 200 affordable housing units, 13,000 square feet of commercial space, a 4,200 square foot child care facility, and 11 affordable for-sale townhomes in San Diego, CA.
The affordable housing units are separated into 70 senior housing units and 130 family housing units. Paseo at COMM22 Family Housing in Logan Heights has 130 apartment units, 13 serving youth eligible for supportive services on a referral basis. The remaining units are available to low-income families and individuals.
Victoria at COMM22 offers 70 affordable housing units for seniors 62 and older. Victoria has 40 studio, one- and two-bedroom apartments with affordable below-market-rate rents and 30-one-bedroom apartments with HUD subsidized rents.
SCS Engineers’ role in supporting the environmental conditions at the site spans over ten years, including environmental assessments, waste characterization, mass grading, and design and implementation of a successful remediation program; thus delivering housing that supports both the social and business goals of the development team and the community.
“The technical issues were challenging, but it’s amazing to see the transformation of vacant lots into vibrant housing that anchor the neighborhood,” says Dan Johnson, SCS Engineers vice president. “We are proud to be able to provide the highest level of environmental and regulatory support for the community.”
The completed COMM22 housing development is a transformational project that has brought tangible benefits to its residents and the entire community. What was once an abandoned, contaminated property is now a thriving cornerstone for the whole neighborhood and a model for transit-oriented infill development and affordable housing with a noticeable increase in the quality of life and a palpable pride of ownership.
Additional Resources
Brownfield development continues to be a hot topic for developers and investors, and they offer excellent opportunities – when you do your homework. SCS Engineers, an environmental consulting firm with 40 years of experience, offers a few tips when considering a Brownfield site.
Although we’ve successfully redeveloped hundreds of properties, one of SCS’s most visible Brownfields projects is the San Diego Padres Petco Park in downtown San Diego, completed in the early 2000s. The site for Petco Park was once a commercial and industrial area with former land uses such as auto repair facilities and gas stations, laundry facilities, and paint and lumber storage facilities. On top of that, it also stored petroleum hydrocarbon and hazardous materials.
What is a Brownfield?
Brownfield land is any previously developed land that is not being used or is under-utilized and may require environmental mitigation to redevelop. These properties are common in many urban areas and often present cost-effective, profitable redevelopment opportunities.
The development of Petco Park is a classic example of a brownfield project, which brought the San Diego Padres to downtown San Diego within a 26-city block portion of the East Village area now known as the Ballpark District. Before developing this beautiful stadium, as well as the new hotel, residential, and commercial development that blossomed around it, this area of East Village San Diego was underutilized. The area housed various commercial and industrial properties dating back to the 1800s, many of which had a legacy of environmental issues.
Because of the aggressive development schedule, and to streamline the redevelopment of the Petco Park and the Ballpark District, SCS and the local health department (the County of San Diego Department of Environmental Health) worked together to create a dynamic approach to its redevelopment of contaminated properties. This approach, embodied in the Property Mitigation Plan (PMP) (also known as a Soil Management Plan), is tailored to the specific property uses as an efficient means to address and mitigate environmental issues (such as dealing with contaminated soils) during the property construction and development process. If enrolled under oversight by the appropriate regulatory agency, the PMP serves as the blueprint for mitigation, soil management, and soil reuse. And when followed, it is designed to result in the closure of environmental cases for the site’s approved uses.
Overall, brownfields typically have environmental issues that can impede new development. But suppose these issues are identified during the due diligence process and integrated into the development and construction processes. In that case, redevelopment protecting future occupants and the environment is achieved while often presenting cost-effective and profitable redevelopment opportunities.
What can you put on a brownfield? Can it be used for residential units?
A brownfield is potentially useful for any structures – including residential. San Diego has numerous examples of brownfield redevelopment, including former burn dumps and landfills, railroad facilities, gas stations, automobile repair facilities, dry cleaners, and more. The feasibility and cost are dependent upon the environmental issues unique to each site. Cleanup standards will be stricter for residential uses, and in some cases, it may not be cost-effective to achieve those standards. Evaluations determine what uses are feasible.
How do you evaluate a Brownfields site?
One should proactively address environmental issues to reduce the risk of cost and schedule overruns or future liability issues while operating these properties as-is or during the due diligence or pre-development process. Identifying environmental risks before acquiring properties is critical, as is assigning potential costs to these risks. Depending on the nature of the transaction, these items are often useful as leverage during negotiations.
Brownfields are normally evaluated by performing a Phase I Environmental Site Assessment (ESA) to first study historic site information and previous uses. A Phase II study may be performed if the Phase I ESA identifies potential issues (known as Recognized Environmental Conditions). Phase II includes collecting and analyzing samples (i.e., soil, soil vapor, and groundwater) to assess whether environmental impacts are present. If enough sampling is completed, the extent of impacts can be estimated.
The American Society for Testing and Materials (ASTM) has standard protocols for Phase I ESA studies. However, as an integral part of your team, your environmental consultant can do more than meet these technical standards. The result of the evaluation provides you with an understanding of how this information will impact your project.
If contamination exists, what do I do?
Your first concern is to get an estimate of how much contamination is present and what it will cost to address, which will affect your bottom line and project feasibility. It’s also important to know that cleaning up contamination is manageable and can even be left on-site during construction and through your planned use in some cases. Your environmental consultant helps you mitigate any risks.
Is funding available to help pay for the site investigation and remediation?
The U.S. Environmental Protection Agency has grant programs that can pay for the assessment and cleanup of brownfields, but these programs are only available to governmental and non-profit organizations. However, a private entity may be able to team with these eligible parties. In addition, grants are available from agencies such as the California State Water Resources Control Board or the Department of Toxic Substances Control for certain soil and groundwater contamination types from gas station or dry cleaner releases. Each grant has its eligibility criteria, and in general, the entity that “caused” the contamination is not eligible. Federal, state, and local tax incentives may also be available.
Obtaining a grant or loan with the help of a qualified environmental consultant or an environmental attorney can be the difference in acquiring, cleaning up, and redeveloping a property. The grants don’t typically cover all the costs associated with the necessary cleanups, but they can cover most of these costs.
I hear insurance can help pay for cleanups as well as help protect buyers.
It can. A new property owner can obtain an environmental insurance policy to cover cleanup requirements, third-party claims for bodily injury and property damage, and associated legal expenses resulting from pollution or contamination. These insurance policies are available with various term lengths, and deductible amounts to satisfy the concerns of lenders or equity investors.
Other solutions include “insurance archaeology” to find old insurance policies that may have coverage for “pollution conditions.” Many firms, including SCS, do this type of work, sometimes on a contingency fee basis.
What are some good risk management strategies for brownfields?
The most important risk management strategy is to have a thorough understanding of the environmental issues on the site and how those issues can impact your redevelopment plans and bottom line. It is critical to have environmental and legal support experienced in strategies for identifying, anticipating, and managing risks on Brownfields.
Are brownfields sites good investment opportunities?
Brownfields can be excellent investment opportunities if you perform thorough due diligence and understand the risks of each site. Many potential sites exist in desirable locations or emerging areas. They should be available below market value and may have been on the market for a long time.
With proper planning and the help of a qualified environmental consultant, the mitigation or remediation of these impacts can be incorporated into the acquisition and development processes and result in a vibrant, profitable project that is protective of human health and the environment.
Author Luke Montague is a vice president with SCS Engineers in its San Diego office.
You’ll find resources for funding brownfield redevelopment here.
AKD Real Estate Investments, LLC (AKD) acquired a brownfields property to build a new Mitsubishi car dealership in West Palm Beach. AKD and Mitsubishi Motors, North America, considered the site because it offered existing infrastructure and prevented additional environmental degradation from building on undeveloped property, or Greenfield, increasingly scarce in south Florida. Brownfields are often centrally located in metro areas with good connections to local infrastructure, including roadways and stormwater utilities. National and state brownfields programs also offer grants and tax credits available to businesses with environmentally-friendly goals.
The property under consideration was on the former Servico Landfill operated by the City of West Palm Beach. Before the landfill closed, the City used it for landfilling municipal incinerator waste, medical waste, and garbage from the 1920s to the 1950s.
The Florida Brownfield Redevelopment Program encourages the redevelopment of potentially contaminated properties, following a careful process that includes environmental engineers and compliance specialists. AKD reached out to SCS Engineers, an environmental engineering and consulting firm specializing in landfills and remediation, to turn this property into a business haven.
SCS Senior Project Manager Kirk Blevins and Project Professional Sanaul Khan met with the AKD to review the dealership’s construction plan. “Understanding the client’s challenges and objectives, Kirk and I worked backward from their business goals and developed a plan to achieve their environmental needs in a way that would minimize delays and conflicts with their construction schedule,” stated Khan.
The team went to work performing environmental due diligence by uncovering records to assess the state of the property. Next, they modified the existing Remedial Action Plan by proposing a cost-effective and practical strategy to address specific environmental concerns.
The Plan is useful to inform regulators and environmental agencies before construction begins. It helps ensure the general contractor is aware and responsible for keeping construction on track and adhering to the remedial strategy, including environmental and safety protocols.
SCS also prepared and submitted all certification documents to be reviewed, approved, and recorded before the dealership’s grand opening while preparing an application to receive Voluntary Cleanup Tax Credits.
“Brownfields remediation is a complex process, but it offers benefits to businesses, investors, and most importantly – the community,” says Blevins.
The Palm Beach Mitsubishi dealership is open for business. Shown here at the opening are Sanaul Khan (left), President and CEO of Mitsubishi Motors North America, Yoichi Yokozawa (center), and Chris Berian of AKD (right).
Resources
The main thoroughfare in Madison, Wisconsin, leading to the state capitol, is going through a major renaissance. Once an idle brownfield, and before that an active industrial-commercial area, the entire block has now been converted to residential, commercial, and office spaces, as well as a youth art center. After extensive due diligence to assess, then successfully remediate significant adverse environmental conditions from past uses, the property’s new mixed-use buildings are open for occupancy. The community art center opens in 2021.
The block formerly housed a dairy operation, gas station, auto maintenance shops, a print shop, and a dry cleaner. These past uses and the historic fill placed on the property resulted in chlorinated solvents, petroleum, polycyclic aromatic hydrocarbons (PAHs), and heavy metal contamination.
Remediating and mitigating environmental contamination and redeveloping brownfields like this one into vibrant, revenue-generating community assets takes pooled expertise from multiple disciplines, including hydrogeology and environmental engineering.
While these projects can provide high value for communities long into the future, they are complex and require large investments up front, explains Ray Tierney, an SCS vice president. Having a team that gets a full picture of the property’s environmental condition, knows regulators’ expectations, and can identify technically sound, cost-effective remediation and mitigation approaches can translate to substantial money savings.
In this case, a solid knowledge base and vetting key details resulted in seven-digit figure savings and facilitated prized redevelopments.
“We identified the amount of soil and groundwater contamination, evaluated strategies to best address the issues, and came up with a cost estimate for remediation. Based on the estimate, along with documentation validating the scientific rationale for our recommendations, the seller reduced their price to account for the legacy environmental liabilities which the purchaser agreed to accept and address as part of the property’s redevelopment.”
SCS Engineers assessed for contamination; oversaw the management of contaminated soil and groundwater during construction according to the materials management plan; supported the client in securing grants, permits and documented compliance with the approved planning documents.
For this project, as is often true in historic urban areas, the greatest expense was dealing with widespread contamination found in the historic fill soils and with groundwater issues.
“Our client is obligated to handle contaminated materials properly. We plan and permit the proper procedures, work with contractors to facilitate the work, documenting that procedures and plans are followed while making sure they only invest what is necessary to be judicious in protecting the environment and public health,” says the SCS Project Manager and Geologist Dr. Betty Socha.
During construction, Socha’s team was onsite to assist contractors in complying with environmental plans and permits, documenting that activities were completed safely and in compliance with Wisconsin Department of Natural Resources (WDNR) expectations. The team oversaw soil removal and management during site demolition and construction of the foundation, including piles and a structural slab. This support system reduces the geotechnical requirement of the underlying soils to reuse more onsite soil safely. But knowing what soil is acceptable and orchestrating the separation of contaminated and non-contaminated materials takes specialized expertise and skill.
“During construction, we evaluate soil conditions, so contaminated soil is safely disposed of at a landfill. But landfilling large volumes of soil is a considerable expense, so it’s important to determine what is safe to be segregated as clean soils for reuse elsewhere. Knowing how to do this efficiently will minimize disposal costs and maximize the use of valued resources,” Socha says.
Getting a handle on groundwater conditions and identifying the best management strategy requires equal attention.
“This property sits on a strip of land (an Isthmus) between two large and prized lakes, with a shallow water table. We thoroughly assessed the groundwater (aka, hydrogeologic) site conditions and managed groundwater generated during construction and dewatering activities,” says Tierney.
“We documented the extent of contamination, and the WDNR confirmed our evaluation that no additional remedial groundwater treatment systems were needed. We could show the contamination was contained enough to pose no risk to municipal wells, private wells, surface water, or other sensitive environments. However, the client still needed a permit to dispose of the contaminated groundwater generated during dewatering for construction of the building foundation and underground utilities,” says Tierney.
Major brownfield redevelopment projects are involved with multistep processes. They begin with a Phase I Environmental Assessment entailing an inspection of the property and a historical review.
That’s where SCS initially identifies potential or existing environmental liabilities from contamination. Then the team confirms the presence of multiple soil and groundwater contaminants through a Phase II Assessment, involving collecting and analyzing soil and groundwater samples.
Next comes a site investigation, a robust testing program to see exactly what is going on. This is where the team further defines contamination, locations, how far it spread, and concentrations. That information lays the groundwork for developing the remedial action plan to file with the WDNR. The team then works with the redevelopment contractors to seamlessly and concurrently manage both the property’s remediation and the buildings’ construction.
In Madison, Socha, Tierney, and their team also helped the developer apply for and win a $500,000 brownfield grant from the Wisconsin Economic Development Corporation, a practice that is as much an art as a science. Additional public support for the project was also received through tax incremental financing (TIF) and the Wisconsin Housing and Economic Development Authority (WHEDA) tax credits for low‐income housing.
“We merge our technical backgrounds to show the land has the potential to be turned into a strong asset that addresses the legacy environmental contamination, promotes public health, and delivers a high-value property that pays taxes and supports important city services,” says Tierney.
It takes technical horsepower to show regulators just how you are addressing contamination. You need to show the economic development group awarding the grant that the project will create well-paid jobs and tax revenue. Equally important, it must be shown that the redevelopment helps address a community need for affordable workforce housing and additional market-based housing,” Tierney says.
Tenants have already moved into the two 11-story mixed-use buildings. In addition, The Madison Youth Arts Center (MYAC) is slated to open in early summer, with a grand opening ceremony this fall. The MYAC includes classrooms, offices, rehearsal spaces, and a 300-seat auditorium.
The final project showcases the heartbeat of this popular downtown space situated between two large lakes, with features such as a rooftop terrace, plazas with seating and green space, and soon to come are 3D urban art installations and murals that tell the story of this long-lived community.
“The redevelopment of brownfields and the creation of projects like the Lyric and the Arden align with the City of Madison’s Performance Excellence Framework Vision of Our Madison – Inclusive, Innovate, and Thriving. These types of redevelopment projects help the City act as a responsible steward of our natural, economic, and fiscal resources. While making efficient use of land and cleaning up brownfields, the City is able to provide workforce housing, job opportunities, and cultural venues, all while enhancing the City’s tax base,” says Dan Rolfs, the Community Development Project Manager for the City of Madison’s Office of Real Estate Services – Economic Development Division.
It takes a village, or in this case – a City, to revitalize an urban brownfield!
Brownfields Resources to Organize, Educate, and Implement Plans in Your Community
Even the simplest impoundment closures come with design challenges. It is a challenge to navigate project constraints, whether technical, regulatory, or financial, to design and implement an effective closure strategy. Cost often helps to determine the “balance” between project constraints when the future end use of a closed CCR surface impoundment or the property it occupies is undefined. When a post-closure end use is defined, finding balance among project constraints to best serve that future use provides rewarding challenges.
SCS Engineers has navigated this balancing act on impoundment closure projects during generating facility decommissioning. Through a presentation of case studies, you can learn how this team has approached ash pond closure planning and execution where the future use of the impoundment site ranged from undefined to the home of a new solar photovoltaic installation. Examples also include potential future industrial use or property sale.
Case studies will highlight how geotechnical, hydrological, regulatory, or simple physical constraints have influenced the design and implementation of CCR surface impoundment closures.
EUEC 2019 in San Diego, February 25-27, 2019. Conference details here.
by Ali Khatami, Ph.D., P.E., SCS Engineers
In south Florida, rising prices of vacant land and unavailability of large parcels of virgin land for development have forced land developers to look into developing old and newly filled lakes. The land price for these lakes is significantly lower than the virgin land and deals are arranged to incorporate the cost of improving the lakefill land into a developable land in the purchase price. Aside from environmental issues that are handled by environmental engineers in relation to obtaining development permits, the ground itself must be improved to sustain the stability needed to bear the proposed development load. Deep Dynamic Compaction (DDC) is proven to be the most economical option for low rise and lightweight developments, such as commercial or industrial warehouses.
The model developed for the Federal Highway Administration (FHWA) report entitled “Dynamic Compaction, Geotechnical Engineering Circular No. 1”, by Robert G. Lukas, dated March 1995, is the primary basis of most DDC programs. Experience of the engineer with the type of the material below the surface is important because the type of material plays an important role in selecting the DDC design parameters used in the model. The design methodology considers four categories of materials in pervious grained soil, semi-pervious soil, partially saturated impermeable deposits, and landfills. The fourth category, landfills, covers waste materials in old landfills but also the material used to fill lakes to create land for new development at a later date.
The material going into a lake may vary depending on the age of the fill placed in the lake. Older lakes filled with debris may include materials that today would never be allowed; while newer lakes are in accordance with state or local regulatory agency environmental permits, which follow a monitoring protocol during filling. The debris in newer lakes may consist of concrete debris, soils, tiles, and any other types of materials classified as clean debris in accordance with the material definitions in the rules.
There are three primary parties involved in this type of brownfields work including the developer, the banker, and the future buyer. Each party has a learning curve to understand and protect their interests.
Developers are cautious because they, very rightfully, have reservations regarding the effectiveness of DDC on the planned investment. Engineers will need several one-on-one and one-on-group teaching sessions with the developer’s primary engineer in charge of the project, and gradually meeting with the engineer’s boss, project director, and eventually the executives of the developing firm. Past successful experience with similar projects play a very important role in justifying the DDC methodology; engineers need to have accurate data and unit costs in tabulated form as part of their arsenal for convincing those in the learning curve.
The process becomes even more complicated when the engineer has designed the DDC program, prepared plans and specification for implementation of the program and the project goes to bid by DDC contractors. To win the work, it is typical for each DDC contractor in the bidding process to return to the client with their version of a DDC program and sometimes less expensive one to put themselves ahead of others. The alternative plans will propose using different equipment, usually the specific equipment that the bidding party already owns, or modeled under a different set of design parameters than the ones prepared by the engineer. Expect communications to become intense, and even with a now more educated developer, they will question every detail of the original planned design. It can be a frustrating and confusing period for all parties.
The engineer must plan to routinely justify his/her design based on design methodologies in literature, justify the design parameters used in the development of the DDC program, and rely heavily on the past performed projects going back a couple of decades. The engineer should even be prepared to obtain permission from past project owners to show the integrity of the building slabs after being in service for many years.
The DDC designer may also need to obtain design parameters from the DDC contractor who has come up with an alternative design to analyze their design and determine any shortcomings in it. If found, further discussions ensue to reexamine the design at hand as the most reliable and the most effective for the developer. Innovation is wonderful, but an expert engineer will not risk the developer’s investment and reputation using unproven technologies; proven technologies are already part of a reputable engineer’s DDC design.
The best way for inexperienced developers to go through the design and implementation phases of such projects is to find an experienced firm with a significant number of similar projects in its experience and trust the outcome of the work by that design firm. Otherwise, the developer will have a very difficult time sorting out the complexities and questions that alternative designs bring forward. The claims of less expensive scenarios without long-term performance justification as to how the foundation will behave over the long term are too risky. The combination of dealing with a new concept for which the developer has no experience and justifying the financial aspects of a properly designed DDC program can make a project even more difficult for an inexperienced developer.
A developer’s project manager should plan to spend significant time with the DDC designer to become familiar with the DDC concept, construction nuances, and the financial aspects of the project. The project manager will need to visit past projects performed by the designer’s firm to confirm claims by the design engineer. Only at that point, the developer’s project manager should proceed with convincing his/her superiors of the validity of the DDC program while asking for assistance from the DDC designer.
Ali Khatami, Ph.D., P.E., is a Vice President with SCS Engineers. He may be reached at
Additional resources are available on these pages: Brownfields and Voluntary Remediation and Environmental Due Diligence and All Appropriate Inquiries.
As the real estate market improves, interest in these brownfields properties is too.
Redeveloping landfill sites can be challenging but has been successfully done in the past. Start your project by engaging the relevant agencies to negotiate the path forward for development. Specific conditions of approval should be negotiated based on prudent engineering practice and real, rather than perceived, public health and safety hazards. With the proper diligence and planning, redeveloped landfill properties can become a valuable community asset.
Read the article and case studies from around the country here.
It is challenging to restore properties with a past, but you can do it on time and on budget if you plan ahead to address contaminated historic fill. Follow these tips and use the brownfield redevelopment checklist to keep your next redevelopment on track.
Design Phase
Consider how contaminated historic fill impacts the following:
Site feature locations – You can reduce or even eliminate landfill disposal costs by carefully selecting locations for your building, underground parking, parking lot, utility, and green space.
Storm water infiltration – Do you know that storm water infiltration devices must be located in areas free of contaminated historic fill? Infiltration devices cannot be located where contaminants of concern (as defined in s. NR 720.03(2)) are present in the soil through which the infiltration will occur.
Subslab vapor mitigation system – Already know you have contaminated historic fill on site? Consider adding a subslab vapor mitigation system to the design of your new building. It is usually much cheaper to install this system in a new building than to retrofit one into an existing building. It can also mitigate radon gas.
Planning & Design
Determine if contamination requires the following plans to manage the construction phase:
Material management plan – It establishes how you will separate excavated contaminated material from material that is not contaminated. It also outlines how you will handle contaminated material, either by disposing of it off site in a landfill or reusing it on site in an approved area such as a paved parking lot. This plan also covers screening, sampling, and testing contaminated materials, if required.
Dewatering plan – If the development requires excavation through contaminated historic fill to depths below groundwater, you will need a dewatering plan to properly manage discharge of the water. You may be able to discharge the water to the storm sewer or the sanitary sewer depending on the type and concentration of contaminants. You must determine local and state permit requirements before implementing your dewatering plan.
Demolition plan – The demolition plan for removing existing structures during redevelopment should include handling, removal, and disposal of potential contaminants such as lead and asbestos. The demolition plan should also address recycling and reuse of existing on site materials like concrete. You may be able to save money by crushing and reusing concrete on site as fill material, or by hauling and crushing it off site to reuse it as fill at another property. This approach can save you considerable money compared to landfill disposal.
Ready to start saving time and money addressing contaminated historic fill at your next redevelopment? Contact Ray Tierney for help evaluating your options in the Upper Midwest, or using the SCS Brownfield Redevelopment Checklist .
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