Tunnel Dam Hydro Station Reservoir Report
Last Updated: December 5, 2025
The Tunnel Dam Hydro Station, also known as Quinebaug River Tunnel Dam #1 Hydro, is a concrete structure located in Preston, Connecticut, along the Quinebaug River.
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Summary
Owned by a public utility, this hydroelectric facility has been in operation since 1906 and serves as a crucial source of renewable energy for the region. With a dam height of 32 feet and a storage capacity of 1650 acre-feet, the station plays a significant role in water resource management and climate mitigation efforts in the area.
Managed by the state regulatory agency DEEP, the Tunnel Dam Hydro Station boasts a spillway width of 443 feet and a maximum discharge capacity of 33,940 cubic feet per second. Despite its significant hazard potential, the station has been assessed as being in satisfactory condition as of the last inspection in July 2016. With a moderate risk rating of 3, appropriate risk management measures are in place to ensure the safety and reliability of the facility.
For water resource and climate enthusiasts, the Tunnel Dam Hydro Station represents a prime example of harnessing the power of water for sustainable energy production. Its location along the Quinebaug River, its impressive storage capacity, and its adherence to state regulations make it a valuable asset in the state's renewable energy infrastructure. As efforts to combat climate change continue to gain importance, facilities like the Tunnel Dam Hydro Station play a vital role in reducing carbon emissions and promoting a greener future for generations to come.
Year Completed |
1906 |
Dam Length |
780 |
Dam Height |
32 |
River Or Stream |
QUINEBAUG RIVER |
Primary Dam Type |
Concrete |
Surface Area |
100 |
Drainage Area |
744 |
Nid Storage |
1650 |
Hazard Potential |
Significant |
Foundations |
Rock |
Nid Height |
32 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Shetucket River At Taftville
|
885cfs |
Quinebaug River At Jewett City
|
1380cfs |
Yantic River At Yantic
|
147cfs |
Little River Near Hanover
|
44cfs |
Pendleton Hill Brook Near Clarks Falls
|
8cfs |
Shetucket River Near Willimantic
|
777cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
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