Occum Reservoir Report
Last Updated: February 22, 2026
Occum, located in Norwich, Connecticut, is a masonry dam on the Shetucket River primarily used for hydroelectric purposes.
Summary
Built in 1900, this dam stands at 14 feet high and spans 520 feet in length, with a storage capacity of 155 acre-feet and a surface area of 65 acres. The dam is regulated by the Federal Energy Regulatory Commission and has a low hazard potential, with a moderate risk assessment rating.
Despite not being state-regulated or inspected, Occum has a history of regular maintenance and emergency preparedness, with an updated Emergency Action Plan in place as of December 2020. The dam's spillway is uncontrolled and has a width of 450 feet, serving as a safety feature in case of high water levels. With a risk assessment rating of moderate, Occum is closely monitored to ensure the safety and integrity of the structure for both water resource and climate enthusiasts in the area.
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Humidity
15-Day Weather Outlook
Year Completed |
1900 |
Dam Length |
520 |
Dam Height |
14 |
River Or Stream |
Shetucket River |
Primary Dam Type |
Masonry |
Surface Area |
65 |
Drainage Area |
465 |
Nid Storage |
155 |
Hazard Potential |
Low |
Nid Height |
14 |
Seasonal Comparison
5-Day Hourly Forecast Detail
Nearby Streamflow Levels
Shetucket River At Taftville
|
819cfs |
Quinebaug River At Jewett City
|
936cfs |
Yantic River At Yantic
|
177cfs |
Little River Near Hanover
|
58cfs |
Shetucket River Near Willimantic
|
630cfs |
Natchaug River At Willimantic
|
231cfs |
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.
Occum
Butts Bridge Road Canterbury