Swains Lake Dam dam
Swains Lake Dam
Swains Lake Dam, also known as Union Lake Dam, is a vital structure located in Barrington, New Hampshire, along the Bellamy River. Built in 1890, this Earth-type dam stands at a height of 17 feet and spans a length of 433 feet, providing a recreational oasis for locals and visitors alike. With a storage capacity of 3,558 acre-feet and a surface area of 407 acres, the dam offers a serene escape amidst the natural beauty of Strafford County.
Maintained by the NHDES DAM BUREAU, Swains Lake Dam is regulated and inspected by the state, ensuring its structural integrity and safety. Despite being classified as having a high hazard potential, the dam has been deemed satisfactory in its condition assessment as of June 2017. The dam's spillway, with a width of 12 feet, serves as an uncontrolled outlet for excess water, while its moderate risk assessment (3 out of 5) highlights the importance of ongoing risk management measures to protect the surrounding community and environment.
As a cherished recreational resource in the region, Swains Lake Dam not only offers a picturesque setting for outdoor activities but also plays a crucial role in water resource management and climate resilience efforts. Its historical significance and continued maintenance underscore the importance of balancing human enjoyment with environmental stewardship to ensure the longevity and sustainability of this essential infrastructure.
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 Swains Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Oyster River Near Durham | 11 cfs | → |
| Isinglass R At Rochester Neck Rd | 53 cfs | → |
| Cocheco River Near Rochester | 97 cfs | → |
| Lamprey River Near Newmarket | 119 cfs | → |
| Winnicut River At Greenland | 17 cfs | → |
| Exeter River At Haigh Road | 52 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Swains Lake Dam.
Boat launches
- Swains Lake Boat Launch
- Canaan Back Road Barrington
- Cathy Schiro O'Brien Cross Country Running Trail Dover
- Oyster River Boat Launch
- Willand Pond Boat Launch
- Piscassic River Boat Launch
Campgrounds
- Old Stage Campground
- Saddleback Campground
- Remote Campsite
- Tidewater Campground
- Green Tops Campground
- Windham Town Forest Tent Platforms
Paddle runs
Track Swains 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 Swains Lake Dam
Where does the data for Swains 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 High 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 Swains Lake Dam.