Federal Energy Regulatory Commission Issues General Correspondence on Golden Mussel Threat at Lower Mokelumne River Hydroelectric Project

Strategic Insights -

The Federal Energy Regulatory Commission (FERC) has issued a general correspondence regarding the closure of boat launches at the Lower Mokelumne River Hydroelectric Project, located in California, due to the discovery of the invasive species golden mussel in the Stockton Region of the Sacramento-San Juaquin Delta. The project's recreation plan requires East Bay Municipal Utility District to operate and maintain boat launches for public use during the project's recreation season. However, the closures are necessary to protect the existing aquatic ecosystems and project infrastructure from the golden mussel infestation.

Key Takeaways:

  • The Lower Mokelumne River Hydroelectric Project's boat launches at Comanche and Pardee Reservoirs have been closed to all private boats and other watercraft for the remainder of 2025.
  • The closures are necessary to prevent clogging of pipes and pumps and to protect the existing aquatic ecosystems from the invasive species golden mussel.
  • East Bay Municipal Utilities District is coordinating with other agencies to identify measures to prevent a golden mussel infestation within project waters.
  • The District is monitoring the effectiveness of an expanded inspection and quarantine program prior to reopening the reservoirs for boating.
  • FERC has requested that the District file a plan and schedule to provide public boating access for the 2026 recreation season within 30 days of the date of this letter.
  • The District is expected to implement the recommended measures to prevent the introduction of golden mussel to waterbodies and reopen the boat launches in a timely manner.
  • The closures exclude any boats with a permanent slip at Comanche Reservoir that were either in the water or in on-site dry storage when the boat launches closed in November 2024.
  • The District will be able to reopen the reservoirs once they have implemented measures to protect against golden mussel, similar to those used for quagga and zebra mussels.

Statistics:

  • 2025: The year in which the boat launches at Comanche and Pardee Reservoirs were closed due to the discovery of golden mussel in the Stockton Region of the Sacramento-San Juaquin Delta.
  • 2026: The year in which the District is expected to reopen the reservoirs to public use, pending the implementation of measures to prevent golden mussel infestation.
  • 30 days: The time period within which the District is required to file a plan and schedule to provide public boating access for the 2026 recreation season.
  • 2 invasive species: The District will implement measures to prevent the introduction of golden mussel to waterbodies, similar to those used for quagga and zebra mussels.

Sources:

  • California's Invaders: Golden Mussel
  • Order Approving and Modifying Amended Proposed Revised Recreation Plan (79 FERC P 62,073) issued May 1, 1997, as amended by Order Amending Recreation Plan (97 FERC P 62,036) issued October 16, 2001 and Order Modifying and Amending the Revised Recreation Plan (151 FERC P 62,138) issued May 28, 2015
  • Golden Mussel Response Framework
  • FERC General Correspondence: FEDERAL ENERGY REGULATORY COMMISSION (MARK IVY, 2025)