What We Can Do:

Ecohydraulics is the synthesis of engineering and biological sciences, linking the roles of physical processes such as hydraulics, sediment transport, and geomorphology to ecological systems. Ecohydraulics work encompasses basic field studies and monitoring to complex computational fluid dynamics (CFD) modeling.

British Columbia:
Barry Chilibeck
Erik Rowland
Ed Wallace
Brian Wardman
Gary Van Der Vinne
Marc Villeneuve
Asia and Africa:
Bruce Walsh
Latin America:
Mike Okun

Using our understanding of ecohydraulics, NHC provides the technical linkage that explains the connections between physical and ecological processes and the human needs for the environment, such as evaluation of development and infrastructure projects, management activities, and operations that affect the aquatic environment. As the scope and frequency of these kinds of projects grow, ecohydraulics is becoming an increasingly important issue in today's world.


  • Monitoring
    Designing and conducting in-field physical, biological, and environmental monitoring for environmental assessment and project design.
  • Modeling
    Examining habitat sustainability and the evolution of stream flows using numerical approaches.
  • Management Systems
    Supervising and managing construction and long-term maintenance of wetland ecosystems and stormwater management projects.
  • Hydrologic and Hydraulic Design
    Developing criteria for stream, wetland, estuarine, and coastal habitats to meet specific riparian and aquatic ecological objectives.
  • Organism Passage
    Assessing passage and movement for aquatic organisms in complex hydrodynamic environments using multi-dimensional numerical or physical modeling.
  • Management and Supervision
    Assessing environmental effects, supporting formal review processes, and acquiring regulatory approvals and permits.


NHC provides ecohydraulic analysis and design by integrating hydraulic design, environmental engineering, geomorphology, and fisheries and biological sciences. Our varied experience includes:

  • Instream Flow Analysis
    • Conducting comprehensive instream flow assessments and analyses using hydrological, hydraulic, and physical habitat simulation (PHABSIM) techniques supported by 1-, 2-, and 3-dimensional CFD numerical modeling.
    • Developing hydrological, biological, and ecological criteria to assess instream flow regimes for aquatic and riparian ecosystems.
    • Interpreting biological data to develop hydraulic habitat use criteria and ecological metrics to assess spatial and temporal aspects of instream flow regimes.
  • Flow Ramping and Stranding Assessments
    • Creating highly specialized tools to assess the hydraulics and potential effects of unsteady flow effects in stream and river channels that may strand or otherwise impact fish and other aquatic species. These tools help assess the ecological aspects of flow regime changes, water quality impacts, and stream productivity.
  • Hydraulic Success Criteria
    • Conducting many hydrologic, hydraulic, and sedimentation analyses to establish indicators of ecological success such as wetland hydro-period characteristics, tidal marsh evolution, floodplain inundation for spawning, spawning gravel transport, egg detachment and transport, and fish passage.
  • Habitat Protection and Creation
    • Projects combining aquatic habitat restoration with flood management, recreation, channel stabilization, and infrastructure development.
    • Analyses and designs to restore aquatic and riparian habitats for salmonids, cyprinids, smelt, and other sensitive fish species, and other imperiled species.
  • Fish Movement, Migration, and Exclusion
    • Using high resolution ecohydraulic analyses of fish migration and exclusion systems to determine the movement of fish in their natural habitat using fish behavior and physiological criteria.

Surveying a diversion channel as part of the Bridge Coastal Fish and Wildlife Restoration Program

Cariboo Dam fishway designed to provide more natural flow hydraulics

2-D ecohydraulic numerical model developed to assess fish movement

Benefits & Results:

  • Desired goals are met for ecological sustainability.
  • Ecological and other objectives are jointly achieved through proper analysis, planning, and management.
  • Timely delivery of quality products to support successful project development, from planning, permits, design, budgeting, and implementation.