Peconic Lake Dam dam
Peconic Lake Dam
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. 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.
Dam data reference
Condition Assessment
- Satisfactory
- No 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.
- 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.
- 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.
Hazard Potential Classification
- High
- Dams 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, environmental 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.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Peconic Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Peconic River At Riverhead Ny | 17 cfs | → |
| Carmans River At Yaphank Ny | 15 cfs | → |
| Swan River At East Patchogue Ny | 12 cfs | → |
| Connetquot Bk Nr Central Islip Ny | 21 cfs | → |
| Nissequogue River Near Smithtown Ny | 31 cfs | → |
| Indian River Near Clinton | 6 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Peconic Lake Dam.
Boat launches
- Peconic River
- Wildwood Lake
- Peconic Bay Boulevard Jamesport
- Middle Road 4805, Mattituck
- Naugles Drive Mattituck
Campgrounds
- Indian Island Park
- Wildwood State Park
- Sears Bellows
- Cupsogue County Park
- Southaven County Park
- Cathedral Pines County Park
Fishing spots
Track Peconic Lake Dam in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Peconic Lake Dam
Where does the data for Peconic Lake Dam come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Peconic Lake Dam.