News and Events - "Featured"

Welcome to our newsroom! Here you will find the latest information about our company, projects and people. Browse articles published by our engineers and scientists in national publications and conference proceedings, view our press releases and read through news coverage of Terracon.

If you are a member of the media, you may contact our media relations representative at media@terracon.com.


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Helping A Hospital: Diagnosing Indoor Air Quality and Building Operation Issues

Hospital culture demands that nothing is as important as the people in its care and those who serve them. So when a healthcare facility experienced elevated relative humidity levels, condensation on ductwork, and mold growth following general renovations and building additions, the building owner contacted Terracon. Our team began an evaluation of the performance of the heating, ventilating, and air conditioning system (HVAC) to determine if the system was maintaining cooling, dehumidification, relative humidity, and positive indoor air pressure per the original design.

DIAGNOSING THE ISSUES
A diagnostic assessment of the building mechanical HVAC and exterior enclosure systems were conducted to determine the potential causes of elevated humidity levels and related issues. Additionally, spotted ceiling tiles and mold growth on interior walls was found in several care rooms and common areas. Our facilities experts determined that the HVAC system was operating at a negative indoor air pressure and was in need of repairs along with recalibration of the automatic controls. With help from the commissioning agent, mechanical contractor for the project, and owner’s maintenance personnel, the automatic controls of the HVAC were re-calibrated and air balanced to provide a net positive indoor air pressure in the building and to correct and maintain relative humidity levels in the acceptable performance range.

The Terracon team of building specialists also provided extensive diagnostics of the building exterior to determine the pathways of moisture infiltration into the building interiors. Partial destructive investigative work was required to the building façade to observe the condition of the building exterior construction, air barriers, and sealants. The building height and limited access to the façade necessitated the expertise of our building exterior professionals trained to access the exterior façade via rope access. Architectural details for the building renovations and additions were studied to understand the designed versus installed methods of weather proofing and placement of air barriers. Extensive visual observations of the building exterior wall sections were also conducted to locate potential pathways of outside air infiltration and air movement between the outdoor environments and the indoor conditioned areas.

MONITORING MOVEMENT

In a further effort to investigate the potential areas of air movement between the outside environment and inside conditioned areas, and due to the urgency and target height, an infrared camera was mounted to an unmanned aircraft system (UAS) to scan the southern façades and identify variations in building surface temperatures. Scanning revealed isolated areas of the building façade that were possible areas of air movement between the outdoor ambient and indoor areas. To perform even more in-depth diagnostics, one area was selected for testing. A propeller blower door fan was installed with calibrated airflow and differential pressure measurement software to accurately determine air movement through the building façade. By testing a baseline of air leakage at an indoor air pressure of approximately 0.01-inches water gauge, air movement was quantified through the selected test area for comparison to any future repairs and improvements to the façade and air barrier. Safe smoke was introduced into the ceiling plenum of the test area to trace movement of air through the façade and other pathways in the exterior wall. The results from testing indicated that careful, detailed repairs to the façade and air barrier would be needed to reduce air movement from the outside environment to the inside areas, mitigating condensation and biological growth inside the building.

To develop a plan for detailed repairs to the elements of the building façade, Terracon assisted the design and contracting team in selecting fire-rated materials and sealants suitable for use in performing needed repairs that would improve the effectiveness of the air barrier and withstand typical building pressures generated by the HVAC system. Terracon performed a test of a prototype of the detailed repair for the test area and identified further areas in the façade for repairs.

MAINTAINING BUILDING HEALTH

As the detailed repairs were being performed, Terracon provided observations and testing of the installed repairs. Terracon will also observe the ongoing operation of the mechanical HVAC system to verify that the representative,interior areas in the building are maintained at desired positive pressure and an acceptable relative humidity. This hard work has paid off, providing a safer, more comfortable environment for the facility’s occupants.


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Experience Prevails: Uncovering Hidden Obstacles

Located just 10 nautical miles from the Atlantic Ocean in Jacksonville, Fla., Dames Point Marine Terminal is JAXPORT’s newest marine facility. Opened in 2009, it includes a state-of-the art container terminal capable of handling an annual volume of 800,000 to 1 million Twenty-Foot Equivalent Units (TEUs). With an increase in container volume, JAXPORT recognized the need for an effective rail connector and the development of an efficient intermodal transfer facility (ICTF). In 2014, it decided on a design-build delivery for the project. Terracon partnered with TranSystems and D.B. Kenyon to deliver a quality project while optimizing the budget within a tight time frame.

FACING COMPLEX PROJECT COMPONENTS

The new facility was constructed on approximately 45 acres of JAXPORT property and required relocating a mile-long public road that bisected the site. Components included remediation of lead from an old gun range facility, wetland mitigation, clearing and grubbing, unsuitable material removal, excavation and filling, importing base material, rock, asphalt pavement, reinforced concrete, roller compacted concrete, high mast LED lighting, buildings, gates, canopy, and railroad track.

According to Tom Selfridge, senior geotechnical engineer in Terracon’s Jacksonville, Fla., office, the team decided to further investigate a minor mention made in a preliminary report of possible debris buried in the soil at the construction site. Historic aerial photos were quickly reviewed and indicated relatively large areas of disturbed ground. These areas were scanned with a geophysical survey, utilizing ground penetrating radar (GPR) and electromagnetic induction, to look beneath the ground surface for possible voids or debris deposits. Finally, suspect areas were ground-truthed with backhoe-excavated test pits. Results of the testing were significant. More than eight acres of the construction site had debris hidden under ground level, including pieces of charred wood timbers and sheets, and shredded metal intermixed with sand.

“Without a thorough investigation of the site, the debris could’ve been missed and negatively impacted the construction,” said Selfridge. Terracon’s early awareness and resolution of the debris issue protected the project’s budget and schedule. Additional value was added by Terracon’s recommendation to screen the excavated debris deposit which allowed for re-use of its sand component and reduction in the volume and cost of the off-site waste disposal. Terracon’s resourcefulness continued to the construction phase as Chris Martin, Terracon materials specialist also in the Jacksonville office, adopted use of a geophysical tool (Kessler MIT Scan T2) to obtain real-time measurements of layer thicknesses during placement of roller-compacted concrete (RCC) pavements. After an initial test strip was completed to calibrate the contractor’s equipment and methods, the RCC was placed in multiple lifts up to a maximum total thickness of 20 inches. In addition to the value of real-time data, the scanner tool saved approximately $20,000 in testing cost as compared to the conventional rotary coring method, according to Martin.

Testing of the rail components required knowledge and application of requirements set forth by The American Railway Engineering and Maintenance-of-Way Association (AREMA). Field density testing was completed on the sub-ballast material and welding of the steel rail tracks was checked by ultrasonic testing.

In January 2016, the Port took beneficial occupancy of a $25 million state-of-the-art ICTF, delivered via design-build, on time and within budget.


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Determining Stability: Evaluating a Tunnel to Predict Performance Under Catastrophic Loading

Could a tunnel constructed more than 50 years ago still rapidly drain a reservoir if a catastrophe happened? This was the question Terracon helped answer regarding the 185-foot deep reservoir at the Broken Bow Hydroelectric Dam in Broken Bow, Okla.

Following Hurricane Katrina in 2005, the United States Army Corps of Engineers (USACE) mandated that each public reservoir be retrofitted to drain if there was a catastrophic event threatening the stability of the reservoir’s dam. To comply with this requirement, Terracon joined the team led by Mead & Hunt to evaluate the complex geology, subsurface conditions, and the concrete tunnel liner condition to determine the stability of the existing tunnel. To make sure the 18-foot diameter diversion tunnel met stability requirements, the USACE needed a geotechnical study performed. In the study, the USACE requested that no test borings, rock coring, or destructive testing of the tunnel liner be performed.

DISCOVERING HISTORICAL RECORDS

As part of the team, Terracon developed a multi-stage work plan to understand the original tunnel construction and assess its current condition. Boxes of USACE files of the original dam construction documents were reviewed, including 14 soil test boring logs, geological studies of the steeply dipping rock formations, and construction plans and photographs of the 1960s construction.

UNDERSTANDING GEOLOGIC CONDITIONS

After gaining a thorough understanding of the tunnel design and the geotechnical/geologic conditions, it was time to investigate the tunnel with the team. With the safety of the workers a priority, Terracon crafted a 200-plus-page safety plan including an activity hazard analysis for each team member responsible for accessing the wet tunnel and climbing the rock outcrops.

The work plan included a review and geologic mapping of nearby outcrops of the same rock formations cut by the original tunnel excavation and performing sensitivity analyses. Geologic strike and dip measurements were made, as well as joint spacing and the location of faults and discontinuities. The team then interpreted aerial Light Detection and Ranging (LiDAR) images of four major outcrops for joint patterns and bedding characteristics of the native bedrock. Rose Diagrams and Stereonet Pole plots were created to define structural geology properties such as the dominant orientation of bedding planes, folds, and faults. Using the collected data, Terracon provided calculated estimates for the Rock Mass Rating characterization parameters (RMR) and the Rock Quality Designation (RQD) for the rock along the tunnel alignment, as well as Headcut Erodability indices.

DOCUMENTING TUNNEL CONDITIONS

The next stage of work included conducting a detailed visual condition study of the concrete tunnel liner, documenting the location and width of all cracks, mapping areas of seepage, and estimating seepage flow. To approximate the compressive strength of the tunnel’s liner concrete, the team also performed Windsor Probe testing. Terracon performed ground penetrating radar (GPR) data acquisition to determine the concrete liner thickness, assess the presence of voids in the liner, and to detect the presence of delaminations within the concrete.

Terracon concluded that most of the original tunnel liner was in good structural condition and suitable for use as an emergency spillway of the Broken Bow Reservoir under high velocity flow. The conclusion that the 55-year-old liner could perform under catastrophic loading was great news. The report did document local areas where the concrete liner was detached from the bedrock face, as well as many areas where active seepage was occurring. To control seepage and fill voids in the liner created by the original wooden blocking points and rotted timber cribbing, Terracon recommended the tunnel liner be pressure grouted with chemical grout.

Controlled and engineered weep holes would be designed and placed through the concrete tunnel liner to relieve hydrostatic pressures. This fast-paced, detailed study was impacted by record rainfalls during the data-gathering field operation. This project was truly a collaborative and seamless effort with Mead & Hunt and the Tulsa District USACE personnel.


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Terracon Foundation Awards $86,390 in Community and University Grants

OLATHE, Kan. ­­– The Terracon Foundation is pleased to announce the award of $86,390 in grants to six universities and 12 community organizations. The Terracon Foundation was established as the community investment arm of Terracon with a goal to reach out and become a real part of the lives of company employees and the communities where they live and work.

University Grants

As part of an ongoing effort to support higher education, the Terracon Foundation presents university grants for graduate-level scholarships, fellowships, and programs in the areas of science, technology, engineering, and mathematics.

This year, the Terracon Foundation has presented a total of $50,000 to six universities:

  • University of Arizona – graduate scholarships;
  • University of Illinois at Urbana-Champaign – Terracon Foundation Fellowships;
  • University of North Carolina at Charlotte – female and underrepresented minority scholarships;
  • University of Texas Rio Grande Valley – Terracon scholarship;
  • University of Washington – graduate geotechnical fellowships; and
  • Virginia Tech Foundation – Terracon Graduate Fellowships.

Community Grants

The Terracon Foundation has also awarded $36,390 in community grants to 12 local, nonprofit organizations that were recommended by Terracon employees involved in these organizations. The Terracon Foundation grants are intended to support education and causes focused on the natural and built environment.

Terracon Grant Employee Champion Location Community Grant Recipient Organization Grant Recipient Location
Bettendorf, Iowa LeadHer Davenport, Iowa
Bettendorf, Iowa Junior Achievement of the Heartland Moline, Ill.
Birmingham, Ala. Freshwater Land Trust Birmingham, Ala.
Cincinnati, Ohio YWCA of Greater Cincinnati, Inc. Cincinnati, Ohio
Dallas, Texas Martha Turner Reilly PTA Dallas, Texas
Lenexa, Kan. Shawnee Mission Education Foundation Shawnee Mission, Kan.
Little Rock, Ark. Boys & Girls Club of Saline County Benton, Ark.
Mountlake Terrace, WA Christ the King School Seattle, Wash.
Tulsa, Okla. A New Leaf, Inc. Tulsa, Okla.
Tucson, Ariz. Tucson Clean & Beautiful, Inc. Tucson, Ariz.
White Bear Lake, Minn. Pine Bend Elementary School Inver Grove Heights, Minn.
Winter Park, Fla. Field Manor Foundation Merritt Island, Fla.

For more information about the Terracon Foundation, visit terracon.com/foundation.

Terracon is an employee-owned engineering consulting firm with more than 4,000 employees providing environmental, facilities, geotechnical, and materials services from more than 140 offices with services in all 50 states. Terracon currently ranks 30th on Engineering News-Record’s list of Top 500 Design Firms. For additional information about Terracon, visit www.terracon.com.


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Brownfields Redevelopment: Revitalizing a Cultural Heritage Center

 

A touchstone to the Hispanic community in Utah, Centro Civico Mexicano (Centro) is a place where generations celebrate the traditions of their heritage. Centro was first established in 1935 by Mexicans who came to Salt Lake City and surrounding communities to work on the railroads and in the mines. Today, the well-loved cultural center is solidifying its commitment to future generations by revitalizing its downtown property; made possible through a combination of brownfields funding tools.

IDENTIFYING HISTORICAL USES

Originally purchased in the 1950s, the Centro property was facing the all-too-familiar challenges of urban neighborhoods—aging facilities in need of repair, pressure from surrounding development as part of downtown gentrification, and options to sell the property and relocate. Knowing the challenges at hand, community leaders decided it was time to reconstruct and design a new facility at the site of Centro’s existing home.

“The best reason for the cleanup and new construction is to build a showpiece representing the history of Hispanics in Utah and to give them something to be proud of, including taking part in an environmental improvement of the District,” said Brandy Farmer, president and CEO, Centro Civico Mexicano.

Serving as a trusted partner, Terracon helped Centro assess the property’s history, identifying past industrial uses on the site and surrounding properties as part of the Phase I Environmental Site Assessment. Terracon discovered the site had been contaminated by Polycyclic Aromatic Hydrocarbons (PAHs) from past coal use, and chromium and petroleum hydrocarbons from other past industrial activities. These needed to be cleaned up to meet the requirements of the new development. Development money was raised to cover the new proposed Centro buildings, but not the environmental costs.

BROWNFIELDS FUNDING SOLUTIONS AID CLEANUP

Terracon provided solutions to address both the environmental issues identified and the unexpected financial challenges associated with the cleanup. By helping Centro prepare successful applications for both an EPA Brownfields Cleanup Grant and a Revolving Loan Fund Cleanup Subgrant from the Wasatch Brownfields Coalition, Centro received $400,000 in funding to aid in the cleanup.

Although a small footprint, this piece of downtown Salt Lake City has a powerful future. The new plan for mixed-use development will include low-income senior housing, offices, classrooms, a multipurpose gymnasium, a rooftop soccer facility, and a black box theater.

“This has been one of my favorite projects. The people working on this are fantastic, and together they are all bringing solutions to the table,” said Craig Eaton, Terracon’s environmental department manager in Salt Lake City. “My thanks go out to everyone at Centro Civico Mexicano, Corroon Development Company, Salt Lake City Corporation, Salt Lake County, Utah’s Voluntary Cleanup Program, EPA Region 8, EPA Office of Brownfields & Land Revitalization, and the generous foundations in the local community.”

Belinda Richard, Terracon’s national Brownfields program manager added, “This project is a wonderful example of how local partners, community members, and regulatory agencies can come together to make a project happen—it takes a village.”


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Terracon Announces Jared Mechetti as Senior National Account Manager

Jared MachettiSACRAMENTO, Calif. — Terracon, a leading provider of environmental, facilities, geotechnical, and materials services, has named Jared Mechetti, P.E., as senior national account manager.

Mechetti joins Terracon with a proven track record of delivering engineering and inspection services throughout the United States. His experience includes managing pursuit and delivery teams for technology, commercial, retail, transportation, water, healthcare, and education projects. At Terracon, Jared will focus on technology, commercial, and retail market segments.

“I am extremely excited about my opportunity to join Terracon,” said Mechetti. “It’s a company that has had tremendous success and an outstanding reputation in the engineering industry. I’m proud to be a part of the team. In this new role, I look forward to working with some of the brightest minds in the business and helping to exceed our clients’ expectations.”

Mechetti has more than 18 years of experience in geotechnical engineering, environmental engineering, and special inspections and construction materials testing. He is a licensed professional engineer in three states. He earned his Bachelor of Science from the University of Oregon and his Master of Science from Oregon State University.

Terracon is an employee-owned engineering consulting firm with more than 4,000 employees providing environmental, facilities, geotechnical, and materials services from more than 140 offices with services available in all 50 states. Terracon currently ranks 30th on Engineering News-Record’s list of Top 500 Design Firms. For additional information about Terracon, visit www.terracon.com.


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Accreditations Matter: Being the Best Project Partner

For many municipalities, protecting the public and homes and businesses from the threat of flooding is a major priority. Based on geographic location and local topographic and man-made drainage conditions, they may be more susceptible to flooding due to heavy rains, hurricanes, and or downstream floodplain issues. Such was the case for rehabilitation of the floodwater-retarding structure for the Olmitos and Garcia Watershed #7 near the Rio Grande Valley in South Texas.

The Heeter Construction project management team quickly recognized the need for a partner with specific experienced staff and accreditation to provide quality control during construction. Terracon had the experienced staff and facilities, and was also able to draw additional staff from our other offices in the region to fully support the project demands.

Unique project needs met

Terracon met the general overall needs and requirements of the project with our ACI and NICET certified personnel and our AASHTO accredited and U.S. Army Corp of Engineers validated laboratory. In addition, the project involved the use of roller-compacted concrete (RCC), a construction technique that is not new to this type of construction project but one that was new to the region. RCC can be simpler, faster, and more economical than conventional concrete using the same components – cement, water, and coarse and fine aggregates – but using a drier mix stiff enough to be compacted into place by vibratory rollers.

With the wide breadth of Terracon’s experience in other regions of the country on similar projects, our team could bring their knowledge of the roller-compacted concrete process to the project and reduce the learning curve for our other staff and quickly support the project. Terracon was also able to provide quality control services that were new to the region as well. This included conducting a Vebe consistency test for RCC and slurry wall inspections (a construction technique used to build reinforced concrete walls in areas of soft ground near open water or with a high groundwater table).

Going the extra mile

Because Heeter could not proceed with certain phases of construction until test results were completed, submitted and reviewed, our team set up a 24/7 schedule and provided on-site quality control throughout the project’s construction stage. To save both time and money, our team also set up a mobile laboratory on site to avoid the need for transporting samples to our main laboratory 40 miles away, saving our client and the project time and money.

By providing the necessary qualified and experienced staff and accreditation along with our knowledge of the specialized construction methods used, Terracon played a key role in supporting Heeter’s on-time delivery of this important project. The result: a safer, more efficient process to make sure floodwaters can be properly controlled to protect the residents, homes, and businesses in the Olmitos and Garcia Watershed #7 region – and a successful partnership.

“Everyone has been fantastic and exceptional in response to our project needs and requirements” said Tony Rathbun, manager/business development, Heeter Construction. “We are very pleased and consider you folks a ‘project partner’ as we move forward.”


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Terracon Expands Facilities Services with North Carolina Acquisition

OLATHE, Kan. – Terracon is pleased to announce the expansion of its facilities services capabilities through the acquisition of Engineered Concepts of Greensboro, N.C., effective immediately. Terracon retains Engineered Concepts’ 10 employees.

Engineered Concepts, founded in 1991, specializes in building enclosure, structural engineering, and facility investigation services. The company serves a range of clients in the commercial, education, and government sectors on projects throughout the Southeast and Mid-Atlantic regions. Engineered Concepts’ experience in building enclosure design and investigation, as well as its structural expertise in new construction, rehabilitation, and preservation, reinforces Terracon’s facilities capabilities and strengthens the firm’s national resources and ability to serve clients.

“We are excited for Engineered Concepts to become part of Terracon’s national facilities practice,” said Bill Brickey, P.E., Terracon Facilities Division manager. “Their significant building enclosure and structural diagnostics experience complements our existing facilities services and will be an asset in providing great value and solutions to our clients.”

Engineered Concepts’ professionals hold licensures in 11 states. Their combined experience in building enclosure design and investigation, structural expertise in new construction, rehabilitation, and preservation, reinforces and deepens Terracon’s facilities capabilities in the Greensboro area and nationally.

“Terracon’s building enclosure and other facilities services are a great fit with our company,” said Rob Kennerly Jr., P.E., president and co-founder of Engineered Concepts. “We look forward to working together to bring an expanded complement of capabilities and resources to our clients going forward.”

Engineered Concepts will operate as Terracon Consultants, Inc. dba Engineered Concepts.

Terracon is an employee-owned consulting engineering firm with more than 4,000 employees providing environmental, facilities, geotechnical, and materials services from more than 140 offices with services available in all 50 states. Terracon currently ranks 30th on Engineering News-Record’s list of the Top 500 Design Firms. For additional information about Terracon, visit www.terracon.com.


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The Advantages of Non-Destructive Testing (NDT) Techniques for Evaluating the Compressive Strength of In-Place Concrete

The evaluation of compressive strength of in-place concrete is often needed for projects of new constructions, structural additions and remodeling, and structural repairs. Traditional method of testing the compressive strength of concrete cores retrieved from a structure can be time-consuming and possibly damaging to the structure when a large number of structural members are under evaluation.  Alternative methods that reduce the needs of coring and cause no damage or limited superficial local damage to the structure are becoming more popular.

Non-Destructive Testing (NDT) Techniques

Non-destructive testing (NDT) techniques of evaluating in-place concrete strength measure some properties of concrete which can be correlated to the compressive strength of concrete cores. The well-known guidance of performing in-place concrete strength estimation are ACI 228.1R and ACI 228.2R which are issued by American Concrete Institute (ACI) Committee 228. Pullout testing is recommended by ACI 228.2R as the primary method of estimating the compressive strength of in-place concrete based on accuracy compared to other NDT techniques.

Test Methods for Determining Material Properties of Hardened Concrete in Existing Construction (referencing ACI 228.2R-13 Table 4.1.1)

Property Method
Primary Secondary
Compressive strength (ACI

228.1R)

Cores for compression testing

(ASTM C42/C42M and C39/C39M);

pullout testing (post-installed)

(ASTM C900)

Penetration resistance (ASTM C803/ C803M)
Relative compressive

strength

Rebound number (ASTM C805/

C805M); Ultrasonic Pulse Velocity (UPV) (ASTM C597)

In-place pulloff test (ACI 503.1R:

BS 1881-207) with appropriate

calibration.

NDT Techniques Prevents Project Delays

Pullout-TestThe Terracon team recently worked with a client on a project where a sixteen-story steel framing structure is proposed to be built on an existing twelve-year-old one-story reinforced concrete structure. The concrete mixture design information and concrete material testing records for the in-place concrete were not available to the client. To assist the client in determining if the existing reinforced concrete structure had sufficient capacity to carry the load from the proposed steel structure, pullout testing was performed on three footings and twenty-nine plinths which were identified as critical structural members by the structural engineer of record.

Terracon performed both core strength testing and pullout testing on 15 structural concrete members to develop a job-specific strength correlation. Once the strength correlation was established, the in-place concrete strength of additional members was estimated with pullout testing only. Pullout testing at each additional location was completed in about 40 minutes total from sample preparation to strength estimation The results indicated that the concrete compressive strengths were structurally adequate per the acceptance criteria given by ACI 221.1R. The pullout testing procedure allowed for testing of more locations more efficiently than if only testing core samples. A significant delay in project schedule was avoided.

Pullout testing is just one of the several NDT techniques that Terracon uses to evaluate in-place concrete strength, depending on project variables. Terracon is experienced with field and laboratory testing and statistical analysis, which assures NDT options that can be coordinated with the client and reliable and resourceful services are delivered in a cost-efficient and time-saving manner.


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Terracon Leads Efforts for “Legacy” Oilfield Site Reclamation

Thousands of oil and gas wells have been drilled in North Dakota over the past six decades – many long before the environmental regulations of today were in place. Today, some of the sites damaged from early exploration and production activity, referred to as “legacy sites”  remain and need attention.

In many cases, legacy site locations have been known for years but could not be addressed due to lack of funding or jurisdiction. Now, under state law with funding allocated and legislation in place, abandoned legacy site wells and production facilities where no responsible party remains, can be evaluated and action taken to address environmental impacts. The goal of this funding under the North Dakota Abandoned Oil and Gas Well Plugging and Site Reclamation Fund (AWPSRF) is to repair damages from legacy oil exploration and production to restore the land to productive use.

Developing feasible corrective action plans

Terracon was selected by the North Dakota Industrial Commission (NDIC) to provide environmental response services to remediate and reclaim legacy sites damaged by exploration and production activities and unclaimed petroleum hydrocarbon and brine releases associated with former well pads, pits, and seismic boreholes. Terracon’s environmental services include environmental response, site investigation, clean-up, remediation, reclamation, and well plugging, as well as drilling or other geotechnical and materials testing services.

Recently, Terracon was tasked with investigating subsurface impacts of a legacy reserve pit in western North Dakota where obvious surface impacts of stressed and dead vegetation were observed below the historical pit toward a nearby creek. A limited site investigation (LSI) was conducted to determine the extent and magnitude of contamination and to provide corrective action recommendations for remediation and reclamation. Based on the LSI results, initial cost estimates to remove and replace impacted soils, and the site’s priority level based on environmental risk, corrective action was put on hold until additional funding could be made available through the state legislature.

The initial design of the corrective action was revised to limit the amount of soils to be hauled offsite and avoid impacts to the nearby creek. The revised corrective action focused on: source removal of the pit and soils identified to be too contaminated to support vegetation based on electrical conductivity and chloride; mixing “borderline” soils and placing them in the bottom of the excavation; and experimenting with a soluble algae bioremediation product in wetland areas. This redesign reduced the cost to the state by more than $500,000 and resulted in 50,000 tons of soil being removed from the site. Because of the success of previous remediation and reclamation projects under the AWPSRF, the state approved additional funds to address the legacy reserve pit.

Restoring the natural environment

A Corrective Action Plan (CAP) was submitted to and approved by the NDIC. The scope of services in the CAP included the solicitation and selection of an excavation contractor experienced in brine and petroleum hydrocarbon soils remediation and selection of a special waste landfill to dispose of the impacted soil. To accomplish goals of final reclamation desired by the state, landowner, and tenant, environmental consulting oversight was provided during excavation to document site activities, field screen soils for segregation, and directly place backfill for grading. A storm water pollution prevention plan was designed as part of the CAP, and the erosion and sediment controls implemented ultimately proved vital to the project as drought conditions at the beginning of the project gave way to many work days being cancelled due to rain. Drone and GIS services were also provided in conjunction with laboratory analytical results to maintain remediation goals throughout the project to ultimately return the impacted area to productive agricultural use.