Specialized Solutions for Complex Work On & Beneath the Water
Brennan delivers marine, environmental, dam, diving, harbor, and energy services with the people, equipment, and expertise for complex water-based projects.
Marine, Environmental, and Infrastructure Services Built for Demanding Projects Est. 1919
Brennan designs and executes innovative solutions for the world’s most complex maritime, environmental, and infrastructure challenges. For more than a century, public and private clients have trusted our teams to plan, manage, and self-perform specialized work above, along, and below the waterline.
Whether your project involves supporting critical energy infrastructure, restoring a contaminated waterway, rehabilitating a dam, maintaining a harbor, or completing complex underwater work, Brennan brings the field experience and problem-solving approach to move your project forward safely and efficiently.
Explore Our Areas of Expertise Our Services
Marine and Environmental Support for Critical Energy Assets Energy Infrastructure
Brennan supports the energy industry with specialized marine construction, environmental remediation, barge transportation, underwater inspection, and infrastructure services. We understand the safety, access, regulatory, and scheduling demands of working at power generation facilities, hydroelectric dams, transmission and distribution sites, and other critical energy assets.
We work closely and collaboratively with owners, engineers, and stakeholders to identify challenges early, improve constructability, and deliver practical solutions in complex above-water and below-water environments.
Areas of Expertise
- Fossil fuel facilities
- Hydroelectric dams
- Nuclear generation facilities
- Transmission and distribution sites
- Environmental remediation
- Marine construction
- Harbor services
- Underwater inspections and surveys
- Maritime security barriers
Restoring Waterways, Wetlands, and Sensitive Environments Environmental
Brennan helps clients address complex environmental challenges through proven remediation, restoration, and water-based construction services. Our environmental experts combine field-tested experience, specialized equipment, innovative patented technologies, and stringent safety and compliance practices to protect natural resources while achieving project goals.
From contaminated sediment remediation, capping with powdered activated carbon, and water treatment to wetland restoration and island building, we deliver solutions that are carefully planned, precisely executed, and built for lasting impact.
Areas of Expertise
- Environmental dredging
- Dewatering and material separation
- Water treatment
- Treatability testing
- Environmental capping
- Hydrographic survey and underwater inspections
- Coastal Resilience
- Wetland and habitat restoration
- Marine and remedial construction
Specialized Dam Construction, Rehabilitation, and Repair Dam Construction
Dam work requires more than general construction experience. It requires crews who understand water control, confined spaces, elevated workstations, underwater conditions, structural repairs, mechanical systems, and the risks that come with working on critical infrastructure.
Brennan supports dam construction and rehabilitation projects with the early contractor involvement, alternative delivery methods, planning, equipment, safety practices, and field expertise needed to complete work in challenging environments above, below, and within the structure.
Areas of Expertise
- Locks and dams
- Hydroelectric dams
- Intakes and headworks
- Golden mussel inspection, response, and eradication
- Cofferdams
- Dewatering
- Concrete placement and repairs
- Gates and actuators
- Grouting
- Leave-in-place formwork
- Precast components
- Underwater dam construction and inspection
Building, Repairing, and Maintaining Water-Based Infrastructure Marine Construction
Founded along the Mississippi River in 1919, Brennan has spent more than a century working in and along inland waterways, ports, rivers, lakes, and coastal environments. Our marine professionals perform construction, repair, inspection, and maintenance services for public agencies, utilities, industrial clients, terminals, railroads, and infrastructure owners.
With specialized marine equipment, experienced crews, and the ability to work above and below the waterline, Brennan is equipped to complete demanding projects in environments ranging from confined inland sites to open-water conditions.
Areas of Expertise
- Above-water and below-water construction
- Barge terminals
- Shipping terminals and piers
- Industrial docks
- Dredging
- Dive construction
- Public waterfronts and marinas
- Bridges
- Underwater imaging technology
- Maritime security barriers
- Railroad support
- Harbor services
- Coastal resilience
Underwater Expertise for Complex Inspection, Dive Construction, and Repair Commercial Diving
Brennan’s commercial dividers are trained by the United Brotherhood of Carpenters and Joiners (UBC) to perform difficult underwater work in demanding environments, including inland and coastal waterways, wastewater facilities, industrial sites, energy facilities, and near-zero-visibility conditions. With advanced underwater tools, remotely operated vehicle (ROV) support, inspection technology, and a strong safety culture, we help clients assess, repair, build, and maintain critical infrastructure below the surface.
Our divers along with our specialized marine construction, environmental, dam, and energy experts, giving clients a fully integrated partner for projects that require both underwater expertise and broader construction capability.
Areas of Expertise
- Dive construction and underwater inspections
- Nuclear diving
- Marine construction and repair
- ROV services
- Underwater construction
- Infrastructure assessments
- Golden mussel inspection, response, and eradication
- Near-zero-visibility diving and imaging
- Wastewater and industrial diving support
- High-quality reports and deliverables
Dependable Inland Harbor Services and Marine Support Harbor Services
Brennan provides inland harbor services for utility companies, dry bulk terminals, specialty commodity shippers, and industrial customers along the Mississippi River and inland waterways. Our harbor teams help keep bulk commodities, barges, vessels, and operations moving safely and efficiently.
From switching and fleeting and vessel management to barge cleaning, repair support, and 24/7 dispatch services, Brennan delivers reliable harbor services backed by experienced crews, responsive communication, and a strong safety culture.
Areas of Expertise
- Short-haul towing
- Switching and fleeting
- Harbor support
- Vessel management
- Barge transportation
- Barge cleaning
- Shipyard and repair support
- 24-hour dispatch
One Partner for Complex Water-Based Work Why Brennan?
Brennan is built to solve technically demanding challenges in and around the water. Clients choose us because we combine specialized crews, purpose-built equipment and technical expertise with open communication, transparent business practices, and a collaborative approach.
From planning through project closeout, we work as a trusted partner, delivering precise execution, professional jobsite management, and the kind of clear, honest communication that makes us easy to work with.
What Sets Brennan Apart
- Award-winning safety performance in safety-critical environments
- Transparent project communication from planning through closeout
- Collaborative, honest delivery with owners, engineers and project partners
- Specialized capabilities across marine, dam, energy, and environmental infrastructure all on one team
- Union craft professionals trained for complex marine construction
- Proven innovative problem solving to keep projects moving
- Purpose-built equipment for inland, coastal, and industrial worksites
Total Quality Management Across the Organization
- ISO 9001 (Quality Management Systems)
- ISO 14001 (Environmental Management)
- ISO 45001 (Occupational Health and Safety Management)
- ASME NQA-1 (2022), 10 CFR 50 Appendix B, and 10 CFR Part 21
