Bridge Hydraulics

What We Can Do:

Bridge hydraulics analyzes the interactions between bridges and rivers or other water bodies. Many bridge failures are caused by flowing water or waves undermining pier and abutment foundations or washing out approach roads. Bridges and approaches are also susceptible to channel shifting and to alterations in morphology induced by dams or upstream land-use changes.

British Columbia:
Des Goold
Ed Wallace
Gene Yaremko
Casey Kramer

Brad Hall
Marc Villeneuve
Asia and Africa:
Bruce Walsh
Latin America:
Guilherme deLima

NHC often conducts hydraulic studies for new bridges as a part of multidisciplinary teams that include structural, geotechnical, and environmental specialists. For existing bridges, we often independently address safety, maintenance, and rehabilitation issues.

Our services include:

  • Planning and Assessment Studies
    Using maps and aerial imagery to evaluate historical channel behavior and stream crossing locations.
  • Flow Analysis
    Determining design water levels, flow velocities, and depths within the channel and overbank areas, including effects of floating debris and ice in cold climates.
  • Scour Analysis
    Estimating scour depths around foundations under design flood or wave conditions, considering past and predicted future channel behavior.
  • Designing Flow Protections
    Designing river training works, and countermeasures against scour, erosion, and debris and ice loads.
  • Integrating Social and Environmental Consideration
    Incorporating environmental and social needs involving fish passage, aquatic and terrestrial habitat conditions, and public access and uses.
  • Inspection
    Conducting field inspections and measurements to evaluate hydraulic adequacy of existing structures.


NHC has 40 years of experience in bridge hydraulics and has completed projects throughout North America and overseas. Our experts participate in technical committees devoted to bridge hydraulics and have acted as contributors and editors to the Transportation Association of Canada's Guide to Bridge Hydraulics, a reference in wide international use.

Our experience includes:

  • Hydraulic Assessment
    Complete hydraulic services for bridge replacement studies including hydrologic investigations to determine design discharges, geomorphic reach assessments, numerical modeling to estimate design velocities and water surface elevations, evaluation of impacts to regulatory floodplains, scour computations to establish pier and abutment foundation elevations, and design of channel stabilization and pier protection features that satisfy environmental requirements.
  • Major Bridges
    Contributing as a part of many multidisciplinary teams to the design and construction of major bridges, including structural and geotechnical design of in-channel piers that require careful evaluation of channel morphology and scour potential.

    Complex 2- and 3-dimensional numerical modeling and constructing large scale physical mobile-bed models to develop and optimize scour and erosion protection works and river training works.
  • Screening and Inspection Programs
    Safety screenings and inspections of bridges to assess scour and identify threatened structures. Inspection programs may include several hundred bridges, and require conducting office reviews and field inspections, assessing basin geomorphology and local stream characteristics, identifying potentially scour-critical structures, and developing mitigation strategies.

Placement of scour protection upgrades at piers,
Pattullo Bridge, BC

Port Mann Bridge construction, BC

Blue Bridge scour evaluation and countermeasure design,
Snohomish County, WA

River 2D Velocity distribution, Nooksack River at
Slater Road Bridge, WA

Benefits & Results:

  • We help clients quickly identify key issues based on the latest research studies, design codes, and modeling software.
  • Our work helps ensure that bridge structures are designed appropriately to be safe, functional, and lasting.