Hopkinton Dam dam
Hopkinton Dam
Hopkinton Dam, also known as Hopkinton Lake, is a rockfill dam located in West Hopkinton, New Hampshire. Managed by the US Army Corps of Engineers, the dam was completed in 1962 and primarily serves the purpose of flood risk reduction. It stands at a height of 71 feet and has a hydraulic height of 64 feet, with a storage capacity of 128,000 acre-feet and a drainage area of 382 square miles.
With a spillway width of 300 feet, the dam has a high hazard potential and is subject to regular inspections and emergency action plans. The USACE manages dam-related flood risks by monitoring the dam's condition, engaging with emergency managers and the public, and updating emergency action plans as needed. As severe weather events can lead to dam releases or potential issues, the USACE works diligently to ensure the dam's structural integrity and mitigate any potential risks associated with flooding.
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 Hopkinton Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Contoocook R Bl Hopkinton Dam At W Hopkinton | 1,080 cfs | → |
| Warner River At Davisville | 405 cfs | → |
| Contoocook River Near Henniker | 782 cfs | → |
| Blackwater River Near Webster | 19 cfs | → |
| Piscataquog River Bl Everett Dam | 8 cfs | → |
| South Branch Piscataquog River Near Goffstown | 143 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Hopkinton Dam.
Boat launches
- Maple Street Hopkinton
- Hopkinton-Everett Reservoir Boat Launch
- French Pond Boat Launch
- Hopkinton
- Clement Pond Boat Launch
Campgrounds
Paddle runs
- Sewall's Island To Manchester Street Bridge
- Begins In Franklin To Sewall's Island
- Thornton Railroad Bridge To Bridgewater/Bristol Town Line
- First Bridge Upstream On Route 100 To Confluence With West River
- Headwaters To First Bridge Upstream On Route 100
- Woodstock/Thornton Town Line To Thornton Railroad Bridge
Track Hopkinton 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 Hopkinton Dam
Where does the data for Hopkinton 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 Hopkinton Dam.