Kezar Falls Hydroelectric Project Reports Deviation from Minimum Flow Requirement

Strategic Insights -

The Kezar Falls Hydroelectric Project, operated by Kezar Falls Hydro, LLC, has reported a deviation from the minimum flow requirement at the Lower Development due to drought-induced low inflows. According to the report submitted to the Federal Energy Regulatory Commission, the deviation began on August 25, 2025, and remains ongoing. The report highlights the measures taken to address the issue, including manually opening the bypass valve to restore additional flow to the bypass reach.

Key Takeaways:

  • The Kezar Falls Hydroelectric Project, located on the Ossipee River in Parsonsfield, Maine, reported a deviation from the minimum flow requirement on August 25, 2025, due to drought-induced low inflows.
  • The deviation occurred when discharge to the bypassed reach at the Lower Development fell below the Article 403 requirement, which stipulates a minimum flow of 125 cubic feet per second (cfs) or inflow to the development (whichever is less) during certain months.
  • The minimum-flow generating unit at the Lower dam has been out of service since June 18, 2025, pending repair, which prevented immediate use of the bypass valve.
  • Operations staff manually opened the bypass valve on August 27, 2025, to restore additional flow to the bypass reach, but inflows continue to be divided between the bypass reach and the Lower powerhouse canal due to wicket-gate leakage.
  • Project staff have visually monitored the bypass reach throughout the deviation and the ongoing drought period, with no adverse environmental impacts observed or reported to date.
  • The project will continue to maintain the bypass valve open to provide bypass flows for the duration of the drought and will seek written concurrence or no-objection from resource agencies for the interim split-flow condition.

Statistics:

  • The minimum flow requirement at the Lower Development is 125 cubic feet per second (cfs) or inflow to the development (whichever is less) during November-March, July, and August, and 175 cfs, or inflow to the development (whichever is less), during April-June, September, and October.
  • Inflows to the development had fallen to approximately 55 cfs on August 25, 2025, with about 30 cfs reaching the bypass via the central sluice section and 25 cfs passing uncontrolled through leakage at the Lower powerhouse wicket gates.
  • The minimum-flow generating unit has been out of service since June 18, 2025, pending repair.
  • Project staff have visually monitored the bypass reach for approximately two weeks, with no adverse environmental impacts observed or reported.

Sources:

  • Kezar Falls Hydro, LLC. (2025, September 5). RE: Kezar Falls Hydroelectric Project (FERC No. 9340) - Report of Deviation from License Article 403 - Minimum Flow Requirement at the Lower Development.
  • Federal Energy Regulatory Commission. (n.d.). Kezar Falls Hydroelectric Project (FERC No. P-9340).