Williams Fork Dam Outlet Works Incident Report

Strategic Insights -

On April 9, 2025, Denver Water experienced a failure in the 20-inch ring jet valve on the outlet works at Williams Fork Dam, prompting an immediate response from the Federal Energy Regulatory Commission (FERC) under 18 CFR 12.10(a). This incident report outlines the requirements for reporting safety-related incidents and Denver Water's response to the failure, including the causes, measures taken to prevent future occurrences, and repair activities.

Key Takeaways:

  • The 20-inch ring jet valve failure occurred on April 9, 2025, at Williams Fork Dam, prompting an immediate response from FERC.
  • The failure was caused by a bent screw shaft on the left side of the valve due to unbalanced load during valve operation and a broken ring/thrust bearing on one of the main gearboxes due to a loose screw.
  • Denver Water isolated the valve by closing the upstream 24-inch cone valve and transitioning flow to the 36-inch ring jet valve within an hour to prevent worsening of the condition.
  • A thorough assessment and repair of the valve were performed by Denver Water Mechanical Engineering and Denver Water Mechanics on April 16th and 17th, resulting in the replacement of damaged/broken components and successful restoration of the valve to service.
  • No personal injuries or private property damages occurred as a result of the failure.
  • Denver Water identified measures to minimize occurrence of and mitigate impacts from this type of failure in the future, including ordering spare components, operators checking gearbox screws and drive shaft collars, and a Denver Water Mechanical Engineer reviewing torque settings of all valve actuators.
  • The incident report includes additional information requested by FERC, such as the level of detail required in any written report and the severity and complexity of the condition.

Statistics:

  • The 20-inch ring jet valve failed on April 9, 2025, at Williams Fork Dam.
  • The valve failure was caused by a bent screw shaft and broken ring/thrust bearing.
  • The repair activities were completed on April 17, 2025.
  • No personal injuries or private property damages occurred as a result of the failure.
  • Denver Water has taken measures to minimize occurrence of and mitigate impacts from this type of failure in the future.
  • The incident report includes additional information requested by FERC, such as the level of detail required in any written report and the severity and complexity of the condition.

Sources:

  • 18 CFR 12.10(a) - Reporting Safety-related Incidents
  • [Source 1: Federal Energy Regulatory Commission]