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Waterbury Dam Spillway Project

Updated: May 2024 

Recommended Rehabilitation Measures per USACE
Recommended Rehabilitation Measures per USACE.

Project Purpose & Benefits:

This project is aimed at addressing the degraded concrete and structurally deficient radial arm flood gates (Tainter gates) at the spillway at the eastern end of Waterbury Dam. The Vermont DEC Dam Safety Program is working with the New England District (NED) of the United States Army Corps of Engineers on the evaluation and design of this project. The project is funded with Federal and State dollars.   

Benefits of the project include:

  • Allow full flood control capability of the dam to be realized while reducing risks of flooding in downstream communities.
  • Improve water quality in Waterbury Reservoir and the Little River by eliminating the need for seasonal drawdowns in water level.
  • Improved Operation and Maintenance of the dam.
  • Improved public safety.
  • Continued support for existing hydropower and recreational uses of Waterbury Reservoir.

 

Waterbury Dam Diagram

 

Project Timeline:

Risk Assessment – Completed 

Lake Champlain Basin Program, $700k

  • Holistic evaluation of complete dam including site visits, reviewing existing plans, records, and data.
  • Identification of Potential Failure Modes (PFMs) of the dam and downstream consequences of dam failure.
  • Inform future project study and design to reduce dam safety risks.

Dam Safety Modification Study (Underway-2024)

Section 1177 Water Infrastructure Improvements for the Nation Act (WIIN), $3M

  • Additional study necessary to better evaluate the risk driving PFMs identified in the Risk Assessment.

  • Quantitative risk assessment of key risk-driving PFMs.

  • Field data collection, including structural inspections of the Tainter Gates, geologic exploration and mapping of spillway bedrock, collection of representative bedrock and concrete samples from the spillway, laboratory testing, and updated analyses.

  • Identification of rehabilitation alternatives.

Concrete Testing
Concrete coring sampling - testing. 
Trunnion
Instrumentation installation for gate friction testing. 
Pier Tilt Monitoring
Concrete degradation - Pier 4 moving to the right. 

Interim Risk Reduction Measures, completed Spring 2024, ~$785,000

To ensure safe and reliable operation of the spillway flood gates, the following temporary risk reduction measures were implemented and are to remain in place until the Spillway Project is complete.

Strut Arm Reinforcement

To allow the strut arms on Gate 2 to safely carry excess stress from Trunnion friction, steel plates were welded to the strut arms to allow for safe and reliable operation.

Steel Plates Welding
Steel plates welded to strut arms of Gate 2.

Heli-lift to Aid in Underpinning the Spillway Bridge

To address overstressing issues in the spillway bridge, top and bottom side steel beams were installed to sandwich the concrete bridge deck. Due to remote access challenges, beams were delivered to their final location via helicopter.

Beams on the ground, ready to be hooked onto the Helicopter
Waterbury Dam Aerial Lift Helicopter.  
Beams being carried by helicopter
Aerial Lift Helicopter transporting beams to final location.
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side view of steel beams
Side view of top and bottom beams.
View from under bottom beams
Underside view of beams.

Design & Permitting (2025-2027)

Section 1177 WIIN, ~$5M

Construction (2027-2029)- Pending Available Funding 

Section 1177 WIIN, ~$67M - $95M 

Additional Resources:

Waterbury Dam Spillway Refurbishment Project Public Information Meeting