Peconic Lake Dam Reservoir Report
Last Updated: January 2, 2026
Peconic Lake Dam, located in Riverhead, Suffolk County, New York, was completed in 1915 and serves as a vital structure for recreational purposes in the area.
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Summary
The dam, primarily owned by the local government, stands at a height of 12.9 feet and has a controlled spillway with a width of 35 feet. It impounds the waters of the Peconic River, providing a surface area of 25 acres and a storage capacity of 83 acre-feet.
Managed by the New York State Department of Environmental Conservation (NYS DEC), the Peconic Lake Dam is regulated, permitted, inspected, and enforced by state authorities. Despite being deemed as having a low hazard potential, the dam is classified as having a very high risk due to its age and condition assessment not being rated. With a history dating back over a century, the dam continues to be a focal point for water resource and climate enthusiasts interested in the management and conservation of freshwater ecosystems in the region.
As climate change impacts water resources and infrastructure, the management and risk assessment of dams like Peconic Lake Dam become increasingly crucial. With the potential for extreme weather events and rising sea levels, ensuring the safety and functionality of such structures is vital for the community's well-being and the preservation of the local environment. While the dam currently meets regulatory guidelines, ongoing monitoring and maintenance will be essential to mitigate any potential risks and ensure the continued recreational and ecological benefits it provides.
Year Completed |
1915 |
Dam Length |
636 |
Dam Height |
12.9 |
River Or Stream |
PECONIC RIVER |
Primary Dam Type |
Earth |
Surface Area |
25 |
Nid Storage |
83 |
Hazard Potential |
Low |
Nid Height |
13 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Indian Island Park
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Wildwood State Park
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Sears Bellows
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Cupsogue County Park
|
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Southaven County Park
|
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Cathedral Pines County Park
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Peconic Lake Dam
Peconic River