Cap and Containment Systems
Cap and containment systems are a foundational element of ENTACT’s environmental remediation and geotechnical construction services. These systems are designed to isolate material in place, prevent off-site migration, manage water and gas movement, and support long-term site closure objectives. Whether used as part of a Corrective Action Management Unit (CAMU), a Resource Conservation and Recovery Act (RCRA) closure, or a custom-built repository, ENTACT delivers comprehensive solutions tailored to each site’s unique needs.
Our team has successfully constructed a wide range of containment systems across the United States, including engineered containment cells, CAMUs, and RCRA-compliant composite capping systems. Our expertise extends to the placement of geosynthetics and conventional soil covers, installation of synthetic turf and vegetative (phytoremediation) caps, and the construction of leachate collection, leak detection, and gas collection/venting systems. We also implement perimeter control systems such as slurry walls and hydraulic barriers, and we construct stormwater management and conveyance systems that maintain the integrity of the cap over the long term.
Where and why cap and containment systems are needed
Cap and containment systems are essential components of long-term site management and environmental remediation strategies. These systems are used to isolate impacted materials, prevent migration to the surrounding ecosystem, and support site closure in compliance with regulatory requirements.
Common applications and environments
Cap and containment systems are implemented across a wide variety of site types, including:
- Former Industrial and Manufacturing Sites: To manage legacy materials within facility footprints or adjacent storage areas.
- Landfills and Waste Repositories: To cap municipal, industrial, or hazardous waste units and reduce infiltration or vapor release.
- Mining Sites: To isolate process residuals, tailings, and residual materials in engineered cells or CAMUs (Corrective Action Management Units).
- Brownfields and Redevelopment Projects: To create physical separation between subsurface materials and new surface uses, such as commercial or public development.
- Power Generation and Utility Sites: To cap and manage residuals and byproducts of past operations, often under post-closure or corrective action frameworks.
Why cap and containment systems matter
Cap and containment systems serve several critical environmental and risk management functions:
- Preventing Infiltration: By limiting the percolation of stormwater into subsurface units, these systems help control the potential mobilization of impacted material.
- Controlling Vapor and Gas Migration: Systems such as gas venting and synthetic caps reduce the risk of vapor intrusion and uncontrolled emissions.
- Isolating Material: These systems physically separate material from human and ecological receptors, aligning with federal and state cleanup objectives.
- Supporting Regulatory Closure: Capping and containment are often key components of closure plans under the Resource Conservation and Recovery Act (RCRA), Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), or state remediation programs.
- Enhancing Site Reuse: Engineered caps, including vegetative and synthetic turf systems, can stabilize sites while supporting redevelopment or ecological restoration goals.
Whether used as interim measures or permanent solutions, cap and containment systems are vital for ensuring the long-term integrity and regulatory compliance of remediation sites.
Our capabilities
ENTACT provides turnkey construction services for a wide variety of cap and containment systems, including both temporary and permanent installations. Our work spans a diverse range of site conditions, regulatory frameworks, and performance objectives. Key capabilities include:
- Corrective Action Management Units (CAMUs): Construction of designated units for the consolidation and management of site-specific impacted material in compliance with regulatory requirements.
- Engineered Containment Cells and Repositories: Excavation, liner installation, and material placement within engineered units designed for long-term isolation and control.
- RCRA-Compliant Composite Cap Systems: Installation of multilayer composite covers, including low-permeability barriers and soil cover systems, to meet federal and state regulatory performance standards.
- Geosynthetics and Conventional Soil Covers: Placement of geosynthetic materials and earthen covers to limit infiltration and support vegetation growth or surface use.
- Synthetic Turf and Phytoremediation Covers: Integration of vegetative and engineered turf systems to stabilize sites while enhancing aesthetics and minimizing maintenance requirements.
- Leachate Collection and Leak Detection Systems: Construction of subsurface drainage, collection, and monitoring infrastructure to manage liquids within capped or contained areas.
- Gas Venting Systems: Installation of passive or active gas collection systems to safely vent methane or other subsurface vapors from capped units.
- Perimeter Hydraulic Control Systems: Installation of vertical slurry walls, sheet pile barriers, or other containment structures to isolate subsurface conditions.
- Erosion Control and Stormwater Management: Construction of swales, berms, riprap, energy dissipators, and surface water conveyance systems to ensure cap integrity over time.
Sustainable and site-specific soulutions
ENTACT’s approach to cap and containment construction balances technical performance with site-specific objectives. For sites with beneficial reuse goals, we offer options such as vegetative caps or synthetic turf covers to stabilize the site while supporting redevelopment or habitat restoration. On industrial or remote sites, we deploy robust, low-maintenance systems that minimize long-term operational demands.
By tailoring each system to the project’s risk profile, regulatory framework, and end use, ENTACT helps our clients achieve durable, cost-effective outcomes.
Self-performance from the ground up
As with all our services, ENTACT self-performs the critical fieldwork required to construct cap and containment systems. Our in-house crews and fleet of specialized equipment enable us to manage large volumes of earthwork, install geosynthetics with precision, and construct complex multi-layer systems with tight tolerances. We collaborate closely with engineers and regulators to ensure systems meet performance criteria and are constructed in accordance with approved specifications.
We also provide integrated construction of associated systems such as gas collection, stormwater control, and erosion protection—critical components for ensuring long-term performance and compliance. Our ability to manage these elements in-house enhances quality control and keeps projects on schedule and within budget.
Frequently asked questions
A cap and containment system is a constructed barrier designed to isolate material in place and prevent interaction with surface water, groundwater, air, or direct contact. Systems typically include engineered layers such as geosynthetics, soil, or vegetation, as well as supporting infrastructure for gas and water management.
They can be. Some caps are designed as interim measures, while others are permanent components of regulatory closure strategies. ENTACT constructs both types and ensures they are designed and built for long-term performance.
Yes. While engineered for durability, these systems require periodic inspection, stormwater management, and vegetation maintenance to ensure continued performance and compliance with post-closure or long-term stewardship obligations.
Cap and containment systems are often constructed under the requirements of the Resource Conservation and Recovery Act (RCRA), Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), and state-led programs. ENTACT is well-versed in navigating these regulatory frameworks and helping our clients achieve closure objectives.
Absolutely. We frequently collaborate with engineering firms and consultants to bring cap and containment designs to life, offering constructability input and execution expertise that streamlines field implementation and ensures regulatory standards are met.
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