Hydraulic Transient Analysis

What We Can Do:

Hydraulic transients, or pressure surges, are created when sudden changes in flow rates occur in pumping and pipeline systems. The pressures created may be high enough to damage or even cause catastrophic failure of pipelines. Specialized hydraulic transient analysis provides the basis for designing surge control measures to protect important infrastructure.

David Axworthy
British Columbia:
Ken Christison
Tom Demlow
Ken Zhao
Marc Villeneuve
Asia and Africa:
Jose Vasquez
Latin America:
Jose Vasquez

NHC provides hydraulic transient analysis and design recommendations for control of adverse pressure surges. These services are used in designing a wide variety of facilities including water supply, wastewater, and stormwater pump stations; water distribution networks; well fields; treatment plants; hydroelectric and thermal power plants; fueling and fire protection systems; and oil and gas pipelines.


  • Surge Analysis
    Thoroughly examining pressure surges for a wide variety of water pipeline and pump facilities.
  • Surge Protection
    Recommending best practices for design and operation of pump stations and pipelines.
  • Valve Recommendations
    Analyzing and determining safe opening and closing times for regulating valves.
  • Forensic Analysis
    Examining pipeline ruptures and failures to determine probable cause of breakdown.
  • Physical and CFD Modeling
    Developing detailed models to determine the best course of action for the project.
  • Field Assessment
    Investigating performance of pump stations and valve operation stations.


NHC has over 35 years of experience providing hydraulic transient advice to government agencies, private industry, and consulting engineering firms. Examples include:

  • Water Transmission Pipelines
    Recommendations on large-diameter water transmission systems, including complex facilities involving hundreds of miles of pipeline, diameters up to 140 inches (3.6 m), and pressures up to 600 psi (4137 kPa).
  • Distribution Systems and Treatment Plants
    Analysis of domestic and reclaimed water distribution systems, including large networks with multiple pump stations, pressure zones, reservoirs, tanks, and pressure regulating facilities.
  • Wastewater Pump Stations and Pipelines
    Hydraulic transient analyses and surge protection recommendations for pipelines conveying wastewater and other fluids, taking into consideration specific fluid properties, entrained air, and maintenance requirements.
  • Hydroelectric Facilities
    Analysis of load rejection and acceptance, load variation, and bypass valve operation for penstocks up to 78 inches (2.0 m) in diameter and pressures to 1000 psi (6895 kPa).
  • Open Channel Systems
    Hydraulic transients in large open channels, such as stormwater drop shafts and tunnel systems up to 30 feet (9.1 m) in diameter.

Field assessment of raw water
pump station, Bakersfield, CA

Surge analysis wastewater
pump station, Kirkland, WA

Surge analysis for fire protection system, MWD Diemer
Treatment Plant, Yorba Linda, CA

Technical Approach & Capabilities:

  • NHC works closely with agencies and consultants involved in the design and operation of pipeline infrastructure to develop solutions tailored to their specific systems and maintenance capabilities.
  • We use hydraulic transient analysis models (normally based on the Method of Characteristics established by mathematics) to predict pressure surges created by operational changes. A range of scenarios is normally investigated in order to define critical conditions for pressure surge control. Examples include pump start-up and shutdown, pump power failure, valve operation, load rejection and acceptance at hydroelectric plants, and pipeline rupture.
  • Technical capabilities include the hydraulic design of surge protection measures such as: pressurized surge tanks, anti-slam vacuum relief valves, flywheels, surge towers, standpipes, surge and pressure relief valves, pump control valves, bypasses, and surge anticipatory valves.
  • Solutions can be tailored to existing systems and maintenance capabilities, such as the design and operation of pipeline infrastructure.

Benefits & Results:

  • Increasing lifespan of existing systems
  • Safeguarding against catastrophic failures brought on by adverse pressures
  • Enabling of safe, better designs for new pipeline systems