A recent examination by SCS Engineers Project Directors Evan Guignon, PE, and Michael Bradford, PE, into geosynthetic liner damage and repairs examined the permeability of geosynthetic liners used in waste containment systems. Their blog focuses on the significance of lined containment, the perception versus reality of liner permeability, liner installations, and liner repairs.
Importance of Lined Containment
Lined containment is crucial for managing solids, liquids, and gases in waste containment systems. Over the past 50 years, regulations such as CCR Title 27, Title 40 CFR, and RCRA (Subtitle D) have emphasized the need for effective containment.
Liner Permeability: Perception vs. Reality
The common perception is that geomembrane barriers are impermeable and that lined ponds are watertight. However, even a “perfect” liner will leak through diffusion. The leakage rate is influenced by the head over the liner, ranging from 1 to 8 gallons per acre per day for a standing head of 1 to 10 feet deep.
Minimizing Leaks: Liner Installations
Successful liner installations involve multiple stakeholders, including manufacturers, installers, design engineers, Construction Quality Assurance (CQA) engineers, and laboratories. Common defects and damages during installation include manufacturing defects (e.g., needle holes), installation errors, equipment damage, and issues with waste/material placement. CQA (Construction Quality Assurance) engineers play a vital role in minimizing these defects and ensuring the liner’s integrity.
Detecting and Managing Leaks
Single-lined facilities use groundwater or soil gas vapor monitoring wells to detect leaks. Dual-contained facilities use leak detection systems called pan lysimeters. The EPA Action Leakage Rate (ALR) recommends 1,000 gallons per acre per day for ponds and 100 gallons per acre per day for landfills. States can set their own ALR values based on the type and function of containment. If leaks exceed the ALR, inspections and repairs are performed to address liner containment.
Liner Repairs
When damage occurs to ponds or cells, repairs are necessary. Damage can be internal (e.g., wrinkles, creases) or external (e.g., rocks, operations, environmental factors). Long-term UV exposure, catastrophic events (e.g., fire or wildlife), and slope stability failures can also cause damage. Repair solutions for ponds and impoundments involve draining, cleaning, and replacing or repairing the liner. The process for cells includes exposing them, cleaning them, and repairing or replacing the liner.
Geosynthetic Liner Conclusion
The design, material manufacturing, installation, CQA services, lab testing, and leak/damage monitoring all contribute to the overall effectiveness of the containment system. CQA, with continuous monitoring and timely repairs, is essential to maintaining the integrity of these systems.
About the Authors:
Evan Guignon, PE has experience with semiannual reporting, exceedance tracking, and regulatory compliance related to environmental projects. He has training in AutoCAD Civil 3D Advanced Landfill Grading Applications and Plant 3D Modeling. Evan’s background includes stream restoration design planning and research involving cement sample preparation and testing according to ASTM standards. Mr. Guignon holds multiple state Professional Engineer licenses.
Michael Bradford, PE brings over 20 years of experience in civil engineering and project management, specializing in solid waste landfill and public works projects. His expertise includes landfill site planning, excavation and grading design, stormwater management, geosynthetic liner design, landfill gas collection and control systems, and leachate recovery system design. Mr. Bradford has managed large-scale landfill expansions and closure projects, including permitting and construction quality assurance, and holds multiple state Professional Engineer licenses as well as CQA/CQC certification for geosynthetic materials inspection. His work includes managing permit modifications and landfill expansions that extended facility life by decades, demonstrating his capability in regulatory compliance and technical leadership.
Evolving Geosynthetic Clay Liners and Coal Ash, Waste360, Eric Nelson of SCS and EREF Researcher Kuo Tian discuss polymer-modified Geosynthetic clay liners that can manage aggressive leachate and meet EPA’s requirements. The polymer-modified alternative system is a sustainable …
The U.S. Environmental Protection Agency (USEPA) has issued guidance to simplify the Title V operating permit renewal process, emphasizing administrative efficiency while maintaining full compliance obligations. The guidance encourages focusing on changes rather than resubmitting unchanged information, but facilities must remain vigilant as renewals can reveal unresolved compliance issues.
Streamlined renewal process: The guidance permits the use of previously submitted materials, incorporation by reference, and directs agencies to concentrate on changes, without altering regulatory or compliance requirements.
Renewal as compliance check: Even if operations are unchanged, renewals prompt reassessment of assumptions, monitoring, and applicability, potentially affecting more than just the renewal itself.
Risks and consequences: Identified gaps during renewal can lead to notices of violation, permit modifications, increased monitoring, enforcement actions, and future scrutiny, often uncovering longstanding issues rather than new violations.
Common issues and affected industries: Problems frequently arise from outdated potential to emit assumptions, monitoring methods, operational changes, or unvalidated permit bases, impacting sectors such as manufacturing, printing, power generation, food production, petroleum, and data centers.
Join SCS Engineers, Sponsors and Exhibitors at the IEA’s Annual Environmental Training Symposium & Conference on May 7th at the San Diego Mission Valley DoubleTree by Hilton in San Diego, CA. For 40+ years, this event has excelled in providing a balance of valuable information, including environmental compliance guidance, and regulatory and legislative updates.
The Annual Environmental Training Symposium & Conference attendees consist of environmental, health, and safety professionals, NGO representatives, environmental engineers, environmental consultants and attorneys, and government affairs representatives. These participants represent manufacturing, biotech, and high-tech companies, as well as the Department of Defense, and federal and state regulators.
The 20+ conference sessions vary from year to year depending on current legislation and regulations. We hope to see you there!
This educational webinar explores how critical pressure informs the definition and refinement of a carbon sequestration project’s Area of Review (AoR) under the Class VI permitting framework. The SCS experts explain why some developers are re-evaluating AoR assumptions, how injection-driven pressure propagation can dominate AoR extent, and why project-specific geology (including fluid salinity and basin structure) can make simplified approaches overly conservative, rather than safer.
In this 17-minute session, we compare calculation approaches (Methods 2, 2A, and 3) and emphasize that early, iterative AoR work can reduce regulatory, cost, and public-trust risks.
AoR must account for both plume extent and pressure effects: Beyond the supercritical CO2 plume, pressurization and project critical pressure determine where fluids could migrate upward through improperly plugged/abandoned wells and potentially endanger underground sources of drinking water (USDWs).
Pressure front propagation is often the controlling factor: Pressure can propagate faster and farther than the mobile plume, and may be altered by geologic structures (e.g., faults).
Fluid salinity and density matter: Higher salinity increases fluid density and generally requires more induced pressure to drive vertical migration; real-world salinity profiles can be non-linear and project-specific.
Method selection depends on data and realism: Method 2 is simple but can yield unrealistic outcomes (e.g., zero/negative critical pressure). Method 2A uses a more detailed equation-of-state approach. Method 3 incorporates risk-based computational modeling of flow through a hypothetical, poorly-plugged well and can better handle complex cases.
Timing and iteration reduce downstream costs: Investing early and periodically re-evaluating AOR assumptions improves defensibility and can avoid costly changes after permitting.
Transparency supports outreach: The AoR process and re-evaluations (including public comment opportunities) can be communicated in plain language to build public confidence in drinking water protection.
SCS is delighted to announce that Tom Mesk, CHMM, will join Justin Rauzon as an SCS Engineers National Expert on Environmental Due Diligence. At SCS, National Experts are recognized professionals with industry-leading expertise in specialized environmental sectors.
In his new role, Tom will work alongside Justin to drive innovation, develop training programs, improve efficiency, and serve as a key resource for the SCS due diligence practitioners who routinely solve complex environmental challenges for our clients. Tom has over three decades of experience in environmental risk evaluation and assessment services at sites across the United States. He has technical and management experience with soil, soil vapor, groundwater, surface water, and indoor air investigations at industrial, commercial, landfill, greenfield, and multi-family residential properties. He is similarly experienced with the assessment, remediation, and/or management of common environmental building hazards, such as asbestos, lead-based paint, radon gas, mold, and polychlorinated biphenyls.
Tom is based in SCS’s multi-disciplinary Asheville, North Carolina office, where he routinely conducts environmental assessments and compliance audits at sites across the United States while providing quality control reviews of various technical documents.
With guidance from our National Experts, SCS teams ensure compliance with national, state, and local environmental regulations. SCS solutions also promote sustainability while maintaining operational efficiency and can minimize potential ecological risks.
Join SCS Engineers at the Environment, Labor & Safety+ Conference (ELS+), taking place April 20–22, 2026, in Houston, TX. This event brings together safety, environmental, and HR professionals across the meat and poultry industry for three days of practical learning, collaboration, and innovation.
ELS+ focuses on the topics that matter most, workplace safety best practices, environmental sustainability initiatives, and labor relations and HR compliance, delivered through insightful sessions and peer-to-peer discussions. Attendees will gain actionable tools and real-world strategies to navigate evolving challenges, strengthen compliance efforts, and support safer, more efficient operations.
Designed for professionals balancing complex responsibilities, Environment, Labor, Safety+ Conference provides a unique space to openly exchange ideas, learn what’s working across the industry, and build meaningful connections with peers and experts.
Be sure to connect with SCS Engineers to learn how we partner with clients to deliver environmental and infrastructure solutions that support safe, compliant, and sustainable operations. Register now.
Ensure your investment in the most appropriate, sound strategies to reduce GHG.
Oregon’s Department of Environmental Quality (ODEQ) has accredited SCS Engineers’ lead verifiers with the electricity power entity specialty under the ODEQ Clean Fuels Program (CFP). The CFP is a regulatory cap-and-trade system designed to reduce greenhouse gas emissions from fossil fuels.
SCS is now accredited to perform EPE (electricity power entity) transaction verifications for businesses and utilities that are required to report under the CFP. The main type of project under the program is electric charging stations.
The ODEQ requires Electricity Power Entities to submit quarterly reports in the Oregon Fuel Reporting System (OFRS) to verify electricity transactions. SCS, as an accredited third-party verification body, ensures data quality and accuracy, with specific verification statements required for electricity suppliers. Clients receive a full verification report including; information on facility boundaries and data sources, a description of accounting procedures and data management, a copy of the verification plan, a description of the data checks the verification body conducted, a log of issues, any qualifying comments the verification body would make about its findings during the verification process, and a copy of the verification report and statement.
SCS GHG verification scope includes entity-wide disclosures, single facilities, public and private electricity generation facilities, compliance offsets, and renewable fuel pathways. SCS Engineers also conducts independent audits of environmental data, including electricity and water usage, waste, and energy use, to support accuracy, compliance, and efficiency across all operations.
In addition, as an Accredited CFP Verification Body in Oregon, SCS Engineers verifies the following programs:
Oregon DEQ: Mandatory Reporting
California Air Resources Board: Mandatory Reporting, Low Carbon Fuels Standard, Offsets
California Dept. of Energy: High Hazard Fuels
Internal Revenue Service: 45Z, Y, and E GREET Models
California Senate Bills 261 and 253 Requirements
Washington: WA ECY Mandatory Reporting and Offsets
M-RET: Renewable Natural Gas Production Measurement, Reporting, and Verification, referred to as MRV in GHG management, to ensure accuracy, completeness, and consistency with voluntary and regulatory standards.
If you’d like to learn more about these programs or cap-and-trade, please get in touch with our GHG experts at SCS Engineers.
Most of the rule’s immediate effects will be on motor vehicles. The regulations directly affected are 40 CFR Parts 85 (Control of Air Pollution from Mobile Sources), 86 (Control of Emissions from New and In-Use Highway Vehicles and Engines), 600 (Fuel Economy and Greenhouse Gas Exhaust Emissions of Motor Vehicles), 1036 (Control of Emissions from New and In-Use Heavy-Duty Highway Engines), 1037 (Control of Emissions from New Heavy-Duty Motor Vehicles, and 1039 (Control of Emissions from New and In-Use Nonroad Compression-Ignition Engines)
The final rule does not affect criteria pollutant emission standards, mobile-source air toxics standards, or vehicle fuel-economy standards (also known as Corporate Average Fuel Economy, or CAFE, standards).
How will the rescission of the Endangerment Finding affect the solid waste industry? To the extent that heavy-duty trucks and equipment become less expensive with no requirements to limit GHG emissions, solid waste companies will see savings. However, major CAA regulatory programs such as New Source Performance Standards for landfills and operating permits for landfill gas control systems are unlikely to be affected, at least in part, because, at the federal level, the threshold triggers for these programs are based on non-methane organic compounds rather than greenhouse gas emissions.
It remains to be seen if EPA will follow through on changes to the Mandatory Greenhouse Gas Reporting Program under 40 CFR Part 98 as proposed last September. Among those changes would be to eliminate GHG reporting for 46 industrial categories, including municipal solid waste landfills and industrial waste landfills. Some of those affected have asked the EPA to continue requiring GHG reporting because they do not want to be subject to numerous state reporting programs, including New York’s new program that takes effect in 2027, as well as California, Oregon, and Washington, which already have GHG reporting. Some states that require GHG reporting directly reference 40 CFR Part 98 and/or rely on the EPA’s electronic Greenhouse Gas Reporting Tool (eGGRT).
Another aspect of the rescission of the Endangerment Finding is any effect that may have on any preemption of state laws outside the motor vehicle context. Several states are not waiting for the EPA in this regard, requiring GHG reporting and disclosures as a matter of state law.
The recission final rule is based on the EPA’s interpretation of the Clean Air Act as a legal matter. Although EPA “continues to harbor concerns regarding the scientific analysis contained in the Endangerment Finding . . . . the Administrator is not basing this action on a new finding under CAA section 202(a)(1). Rather, we conclude that the EPA lacks statutory authority to resolve these questions under CAA section 202(a)(1).” Section 202(a)(1) covers emission standards for new motor vehicles or new motor vehicle engines.
Boiled down to its essence, EPA is saying that it never had the legal authority from Congress to regulate GHGs under the Clean Air Act. It says that the CAA addressed air pollution having local and regional impacts, not pollution that may affect global climate change. By taking this approach, the EPA avoids addressing climate science altogether.
Under the Supreme Court’s “major questions” doctrine, President Obama couldn’t regulate greenhouse gas emissions outside the fence line as part of the Clean Power Plan in the electric utilities sector. President Biden couldn’t require COVID-19 vaccinations or forgive student loans en masse. President Trump might not have been able to impose tariffs under the International Emergency Economic Powers Act because such major questions require specific congressional authorization. EPA cites the major questions doctrine as requiring rescission of the 2009 Endangerment Finding.
The goal appears to be to secure the Supreme Court’s affirmation of the EPA’s current views before Mr. Trump leaves office. The Court has considered aspects of EPA’s GHG regulations from time to time since the 2009 Endangerment Finding was published. Of course, the Court said that EPA could prepare an Endangerment Finding, but it never directly considered the finding itself. If the Court ultimately rules that the CAA does not authorize the EPA to regulate GHGs, one assumes that, until Congress passes a new law addressing GHGs, there will be no such regulation at the federal level.
If you have questions about federal, state, or local air quality regulations, reporting, or verification, please contact the experts at SCS Engineers.
SCS Engineers is proud to participate in Lucky Leaf Expo Minneapolis! Taking place February 27–28, 2026, at the Minneapolis Convention Center. As Minnesota emerges as one of the nation’s next major cannabis markets, this two-day conference brings together industry professionals, regulators, entrepreneurs, and job seekers to explore opportunities shaping the future of cannabis in the region. SCS Engineers partners with clients to address environmental compliance, odor control, zoning, and infrastructure planning challenges critical to sustainable cannabis operations. Register today!
Visit Booth #125 to connect with Eva Luu, Sonya Betker, Armando Hurtado-Garcia, and Christopher Petro, and attend the following SCS Engineers-led sessions:
Cannabis Without the Complaints: Zoning, Odor Control, and Sustainable Industry Growth
Presented by Christopher Petro and Armando Hurtado-Garcia This session explores how cities can balance economic growth with community impacts through effective zoning, odor control standards, permitting strategies, and operational best practices that support long-term industry success.
Making Scents of Odor Control: Evaluating Mitigation Technologies and Trade-offs Presented by Eva Luu and Armando Hurtado-Garcia Drawing on years of field testing, this presentation compares odor control technologies by evaluating environmental conditions, maintenance needs, cost-effectiveness, and public perception to help decision-makers select the right solutions for specific operational scenarios.
As an employee-owned environmental consulting and construction firm, SCS Engineers supports the communities we live and work in year-round. But we all want to be doing something extra during the holidays.
In 2024, SCS donated to 43 local registered IRS 501(c)(3) charities during the holidays, positively impacting over 90,000 people! Our Corporate program has proven to be successful, so we plan to grow it this year.
In addition to supporting this year’s annual SCS Young Professional Group’s holiday fundraising, we plan to send significant donations to the four charities below that align with the environmental nature of our business and do so much for others. We will continue funding the Robert Stearns SWANA and the Environmental Research & Education Fund Scholarships.
These charities rely on consistent donations from patrons like SCS and you. We thank them all for their continuing humanitarian work. As always, we will continue to donate year round to the Red Cross and World Central Kitchen in support of people impacted by natural disasters worldwide.
All of us at SCS Engineers wish you a joyous, happy, and healthy holiday season!
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This educational webinar explores how critical pressure informs the definition and refinement of a carbon sequestration project’s Area of Review (AoR) under the Class VI permitting framework. The SCS experts explain why some developers are re-evaluating AoR assumptions, how injection-driven pressure propagation can dominate AoR extent, and why project-specific geology (including fluid salinity and basin structure) can make simplified approaches overly conservative, rather than safer.
