Vermont Public Utility Commission Approves Changes to Molly's Falls Hydroelectric Facility

Strategic Insights -

The Vermont Public Utility Commission has approved Green Mountain Power Corporation's request to modify the emergency spillway project at the Molly's Falls Hydroelectric Facility, citing the need to reduce the risk of potential failure due to wet soils in the area. The modification includes replacing a rock-armored swale with a culvert and a secondary rock-armored swale to manage surface waters and prevent erosion. The Commission determined that the proposed changes will not have an undue adverse effect on public safety or the environment, and will serve the public good.

Key Takeaways:

  • The Vermont Public Utility Commission approved Green Mountain Power Corporation's request to modify the emergency spillway project at the Molly's Falls Hydroelectric Facility.
  • The modification includes replacing a rock-armored swale with a culvert and a secondary rock-armored swale to manage surface waters and prevent erosion.
  • The proposed changes will reduce the risk of potential failure due to wet soils in the area and will not have an undue adverse effect on public safety or the environment.
  • The modification will also provide an improved public safety benefit due to the culvert's higher stability.
  • The Commission required Green Mountain Power Corporation to provide a status update on the anticipated filing date of the Flow and Water Level Management and Monitoring Plan and the Dissolved Oxygen Monitoring Plan.
  • The approved modification will not affect the implementation of the requirements of the Memorandums of Understanding between Green Mountain Power Corporation and the Vermont Agency of Natural Resources.

Statistics:

  • The emergency spillway project at the Molly's Falls Hydroelectric Facility was approved in Case No. 20-2570-PET.
  • The Commission received comments from the Vermont Agency of Natural Resources (ANR) and the Vermont Department of Public Service, with ANR requesting supplemental documentation and the Vermont Department of Public Service not opposing the petition.
  • The modification will involve replacing a 140-foot rock-armored swale with a 140-foot culvert to relocate an intermittent stream.
  • The proposed culvert will be a three-foot diameter, dual wall, high-density polyethylene pipe with a smooth interior.
  • The modification will provide an improved public safety benefit due to the culvert's higher stability.

Sources:

  • Vermont Public Utility Commission, Case No. 22-3438-PET, Order Approving Changes to Molly's Falls Dam Emergency Spillway Project (12/14/2022)
  • Vermont Public Utility Commission, Case No. 20-2570-PET, Order Approving Changes to Molly's Falls Dam Emergency Spillway Project (March 23, 2021)