| Safety
set out the intended gate configuration, operating philosophy and performance requirements under both routine and emergency operating conditions, together with the functional scenarios the gates would be expected to perform throughout their operational life. KGAL undertook a comprehensive technical
review, providing early feedback on design assumptions, operational requirements and areas requiring clarification before detailed engineering commenced. Establishing a clear understanding of the functional requirements at the outset ensured that subsequent assessments rested on an engineering understanding shared by the client, designers and operational stakeholders.
Identifying hazards while the design
remains open With the functional requirements established, the project team undertook a series of formal Hazard and Operability (HAZOP) workshops.. The workshop brought together specialists from BC Hydro’s engineering, operations, and dam safety teams alongside the gate designers and KGAL’s reliability engineers. Using a structured approach, the team systematically challenged each operating scenario to identify credible hazards, equipment failures, operational deviations and human factors that could compromise safe operation of the gates. Rather than focusing solely on the equipment, the assessment considered the complete operational system, including mechanical, hydraulic, electrical, electronic and control elements, together with the interaction of operators and maintenance personnel. For every identified hazard, the team evaluated the potential causes, consequences, existing safeguards and opportunities for further risk reduction. Where existing protection measures were considered insufficient, actions were identified to eliminate or mitigate the risk through improved design. This collaborative exercise established the
hazard register that guided every subsequent stage of the assessment.
Informing the developing design It is worth being clear about the starting point.
This was not a blank sheet: a preliminary gate arrangement had already been developed when the reliability study commenced. What the HAZOP
findings changed was the direction in which that arrangement subsequently developed. Rather than progressing independently, the gate designers worked closely with BC Hydro and KGAL through an iterative process in which identified hazards continually informed design decisions. This enabled potential risks to be engineered out wherever possible through design simplification, improved redundancy, enhanced operational controls and more resilient system architecture, including the provision of multiple independent drive paths, so that no single loss of power or control would leave the gates inoperable. By the conclusion of this phase, the design
provided sufficient detail to define the principal mechanical equipment, lifting arrangements, electrical infrastructure and control philosophy.
Assessing failure modes Once the design had matured, KGAL facilitated a
comprehensive Failure Modes and Effects Analysis (FMEA). Where the HAZOP identified potential hazards, the FMEA examined how individual components could fail and what effect those failures would have on the performance of the LLO gate system as a whole. Each major subsystem, including the mechanical drive train, power supplies, electrical controls and instrumentation, was systematically analysed to identify potential failure modes, likely causes and resulting operational consequences. The assessment also identified the protection layers that would either prevent failures from occurring or mitigate their consequences should they arise. Beyond identifying weaknesses, the FMEA built a detailed understanding of system behaviour under fault conditions and highlighted opportunities to improve resilience. The resulting data formed the basis for the quantitative reliability assessment undertaken during the next phase.
Quantifying system reliability With the potential failure modes identified, all
significant failures were carried forward into a Fault Tree Analysis (FTA) to quantify the reliability of the proposed design. Fault Tree Analysis is a top-down analytical
technique that models how individual component failures, together with operator actions and
www.waterpowermagazine.com | September 2026 | 13
Extract from the Fault Tree
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45
