Lake Sunapee Dam dam
Lake Sunapee Dam
Lake Sunapee Dam, located in Sullivan, New Hampshire, is a concrete buttress structure completed in 1932 with a primary purpose of recreation. Owned by the state, the dam is regulated, permitted, inspected, and enforced by the New Hampshire Department of Environmental Services Dam Bureau. The dam stands at a height of 14 feet and spans 80 feet, holding a storage capacity of 40,900 acre-feet and serving a drainage area of 44.8 square miles.
With a significant hazard potential and a moderate risk assessment rating, Lake Sunapee Dam poses a potential threat that is closely monitored through regular inspections and emergency action plans. The spillway, with a width of 14 feet, is uncontrolled, and the dam has a maximum discharge capacity of 600 cubic feet per second. The dam's condition is currently not rated, but it meets state regulatory standards and has a history of compliance with inspection protocols.
The dam's location on the Sugar River in Sunapee serves as a vital recreational resource, providing opportunities for boating, fishing, and other water-based activities. Despite its age, Lake Sunapee Dam continues to play a crucial role in water management and conservation efforts in the region, highlighting the importance of sustainable infrastructure for climate resilience and resource protection.
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 Lake Sunapee Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Sugar River At West Claremont | 555 cfs | → |
| Contoocook River Near Henniker | 1,100 cfs | → |
| Warner River At Davisville | 527 cfs | → |
| Ottauquechee River At North Hartland | 427 cfs | → |
| Blackwater River Near Webster | 19 cfs | → |
| Smith River Near Bristol | 257 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lake Sunapee Dam.
Boat launches
- Sunapee Lake Boat Launch
- Perkins Pond Boat Launch
- Lake Avenue 51, Newbury
- Rand Pond Boat Launch
- Lake Coniston (Long Pond) Boat Launch
- Pleasant Lake Boat Launch
Campgrounds
- Northstar Campground
- Camp Wilmot
- Mt. Ascutney State Park
- Fox Brook Tent Site
- Ascutney Mt Stone Hut
- Clark Brook Campsite
Paddle runs
- Begins In Franklin To Sewall's Island
- Sewall's Island To Manchester Street Bridge
- Headwaters To Crossing Of Route 100 Near Route 155
- First Bridge Upstream On Route 100 To Confluence With West River
- Thornton Railroad Bridge To Bridgewater/Bristol Town Line
- Headwaters To First Bridge Upstream On Route 100
Track Lake Sunapee 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 Lake Sunapee Dam
Where does the data for Lake Sunapee 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 Significant 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 Lake Sunapee Dam.