Where your needs intersect with the natural environment, we have the expertise to support your projects. Our engineering and environmental consultants offer practical and technically sound solutions to help you solve your most complex geological and environmental challenges. Whether it’s protecting infrastructure, meeting stakeholder requirements, or managing environmental data, the combination of our international experience, technical expertise, and professionalism gives us the skills and confidence to reach your project goals.


Our staff of national experts across specialized disciplines provides systematic and comprehensive solutions. Our renowned geotechnical team has expertise in virtually every aspect of geotechnical engineering, while our experienced dams and hydraulics team delivers innovative and sustainable water management infrastructure.


When it comes to environmental compliance and remediation, our team is backed by 40 years of experience in advanced technical consultation, funding, strategy implementation, field services, engineering, and permitting. Additionally, our environmental management and natural resources professionals provide comprehensive services for natural resource identification, avoidance, and minimization of impacts, as well as mitigation and restoration planning, design, and construction.

Count on us to solve your most complex geotechnical, dam, or environmental engineering challenge. Our mission is your success.



With more than 100 years of experience in subsurface conditions, our specialists have the in-depth knowledge and expertise to excel on the most challenging geotechnical assignments. We provide innovative solutions for foundations, underground construction, earth structures, groundwater resources, and marginal building sites. Our geotechnical engineers and geologists specialize in landslides, sinkholes, mine subsidence, seepage, expansive soils, and seismic activity. We’ve completed more than 1,000 subsurface and geophysical projects across the U.S.–from small-scale projects to large, complex dams, highways, bridges, and underground structures.


Dams and Hydraulics


Aging infrastructure, climate change, extreme weather events, and rising sea levels present challenges to our communities. We help our clients stay prepared with innovative, cost-effective designs to renew their existing dams or bring new dams online to meet current needs, plan for the future, and keep communities safe. Our designs serve our clients’ needs for water supply, flood damage reduction, navigation, and recreation, to sustain communities. Since our founding more than 100 years ago, our Dams and Hydraulics team has designed more than 100 new dams, modified over 250 dams and 50 levee systems, and evaluated the safety of more than 500 dams.


Environmental Compliance and Remediation


Our environmental expertise spans a wide range of environmental, site assessment, regulatory compliance, and remediation services. With experience in federal, state, and local regulations, we provide permitting and compliance support. Our cost-effective remedial services help clients solve existing remediation needs and identify potential hazards before they impact operations and result in adverse environmental conditions. Our full complement of services includes everything from initial site investigation to final remedial action implementation and compliance audits.


Environmental Management and Natural Resources


Gannett Fleming has an experienced team of specialists, including social scientists, economists, biologists, natural resources specialists, archeologists, architectural historians, and other technical staff, who provide creative approaches to environmental challenges.


We work collaboratively with our clients to help them best manage the resources that their business and future projects could impact. We offer comprehensive natural resource identification; avoidance and minimization of impacts; mitigation, restoration planning, and design; and preparation of permit applications.

Geotechnical Services

Site Evaluation


  • Field reconnaissance and geologic mapping
  • Geophysical investigations
  • In-situ tests
  • Seismic analysis
  • Subsurface explorations
  • Subsurface investigations.




  • Downhole geophysical logging and television
  • video
  • Electrical resistivity (2D and 3D imaging)
  • Electromagnetic
  • Ground penetrating radar
  • Leak detection
  • Magnetometry
  • Marine geophysics
  • Microgravity
  • Seismic (refraction, reflection, downhole,
  • cross-hole, and MASW)
  • Self potential
  • Very low frequency
  • Vibration monitoring.


Geotechnical Testing


  • Field testing and instrumentation
  • Construction monitoring.


Foundations Analysis, Design, and Inspection


  • Construction oversight
  • Instrumentation
  • Remedial design
  • Reservoir, dam, and levee inspections and assessments
  • Seepage analysis
  • Seepage investigation and monitoring.


Ground Modification


  • Mine stabilization
  • Sinkhole/cavity remediation
  • Slope stabilization
  • Grouting
  • Earth reinforcement
  • Soil densification
  • Dewatering.

Seepage Remediation


  • Construction oversight
  • Instrumentation
  • Remedial design
  • Reservoir, dam, and levee inspections and assessments
  • Seepage analysis
  • Seepage investigation and monitoring.


Geologic Hazard


  • Fracture trace analysis
  • Geographic information system analysis and mapping
  • Geologic mapping and structural analysis
  • Geophysical investigations
  • In-situ testing
  • Infiltration assessment
  • Instrumentation
  • Hydrogeologic investigations
  • Landslide and settlement monitoring
  • Mapping quarry highwalls
  • Roadcut maintenance surveys
  • Rock slope scaling volume verification
  • Rockfall prediction
  • Subsidence monitoring.


Groundwater and Hydrogeology


  • Groundwater source of supply
  • Groundwater remediation
  • Groundwater control.




  • Cement grouting or high-mobility grouting
  • Compaction grouting or limited-mobility grouting
  • Contact grouting
  • Jet grouting
  • Low-mobility grouting
  • Permeation grouting
  • Sanded grouts or medium-mobility grouting.


Retaining Walls


  • Design of embankment fill walls
  • Design of excavation support–temporary and permanent
  • Existing wall analysis to evaluate rehabilitation or reconstruction options
  • Existing wall inspection
  • Slurry wall/diaphragm wall design
  • Retaining wall design.

Dams and Hydraulics Services

Dam Investigation and Design


  • Dam investigations/inspections
  • Earth structures
  • Emergency response planning
  • Final design and post design
  • Foundations
  • Geophysics
  • Ground modification
  • Hydrologic and hydraulic modeling
  • Permitting
  • Planning
  • Risk-informed decision-making
  • Security
  • Site characterization
  • Site evaluation
  • Testing and instrumentation.


Dam Risk and Reliability Assessments


  • Dam failure impact assessments and hazard/consequence classification
  • Dam safety inspections
  • Dam surveillance and safety reviews
  • Independent External Peer Review (IEPR)
  • Portfolio risk assessments
  • Post-disaster inspection and assessment
  • Probable Failure Mode Analysis (PFMA)
  • Qualitative and quantitative risk assessment.


Emergency Action Plans and Exercises


  • Early warning notification message crafting
  • Emergency operations and response planning
  • Dam failure and inundation modeling
  • Defining populations at risk
  • Incident detection, evaluation, and response
  • Interagency coordination
  • Property damage/loss-of-life mitigation plans.

Flood Hazard and Risk Assessment


  • Consequence analyses
  • Dams and levees
  • Emergency action planning
  • FEMA National Flood Insurance Program
  • Flood mitigation alternatives analyses
  • Geographic information systems.


Planning Services


  • Building Information Modeling
  • Cost estimating and financial analysis
  • Demand studies
  • Feasibility studies and alternatives analysis
  • Flood studies
  • Geospatial
  • Groundwater development studies
  • Hydraulic modeling
  • Non-revenue water studies
  • Public outreach
  • Regulatory analysis and permitting
  • Resiliency and security assessments
  • Safe yield and water supply investigations
  • Sewage facilities planning
  • Site master plans
  • Treatment pilot testing
  • Utility management consulting
  • Wastewater treatment process modeling
  • Water quality and treatment process selection.

Environmental Services

Subsurface Investigations and Remediation


  • Brownfield program management
  • Emergency response oversight, sampling, and reporting
  • Quality assurance/quality control
  • Remedial action and corrective action design, implementation, and closure
  • Risk-based corrective action
  • Soil and groundwater investigations
  • Vapor intrusion investigation and mitigation.


Environmental Due Diligence


  • ESA Phase I, II, III investigations
  • Industrial lease reviews and RD-2 forms
  • Litigation support
  • Waste reduction and minimization audits.


Engineering Design


  • Fleet fueling, design, installation, removal, and closure assessments of underground storage tanks and aboveground storage tanks
  • Sustainable infrastructure design.


Facility Planning


  • Comparison of alternatives and recommendations
  • Environmental risk and liability management
  • Facility response planning for bulk fuel terminals
  • Spill containment and countermeasure planning.


NEPA Compliance and Documentation


  • Administrative records
  • Categorical exclusions
  • Decision documents
  • Environmental assessments
  • Environmental impact statements
  • Planning and overall process management
  • Public involvement and agency coordination
  • Workshops to develop needs and analyze alternatives.

Natural Resources and Restoration


  • Aquatic habitat and stream surveys
  • Agency coordination
  • Avian surveys and reports
  • Endangered and threatened species surveys
  • Forest stand delineation and conservation plans
  • Geomorphology and soil science
  • Invasive species surveys
  • Passive treatment systems for mining and utilities sites
  • Stream restoration design
  • Water quality assessment, modeling, and monitoring
  • Wetlands and waterways identification, delineation, functional assessment, and mitigation design.


Regulatory Compliance


  • Air emissions calculations and permitting
  • Asbestos, lead, and mold assessment
  • Interface and negotiations with local, state, and federal agencies
  • National Pollutant Discharge Elimination System (NPDES) permitting and compliance
  • Non-hazardous/hazardous waste management
  • Permit applications
  • Spill prevention, control, and countermeasure (SPCC) plan preparation
  • Stormwater permitting
  • Stormwater pollution prevention plan (SWPPP) preparation.


Socioeconomic Studies and Cultural Resources


  • Community impact analysis
  • Comprehensive plans and ordinance review and development
  • Environmental justice analysis
  • Economic impact and cost-benefit analysis
  • Labor, employment, and industry trends analysis
  • Land use planning and analysis
  • Noise analysis and mitigation
  • Population analysis
  • Stakeholder involvement and consultation.



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