Granite Lake Dam dam
Granite Lake Dam
Located in Nelson, Cheshire County, New Hampshire, Granite Lake Dam stands as a vital structure on Granite Lake Brook. Completed in 1932, this earth dam serves primarily for recreational purposes, offering a storage capacity of 990 acre-feet and a normal storage level of 765 acre-feet. With a dam height of 11 feet and a length of 90 feet, this structure covers a surface area of 211 acres and has a drainage area of 4.21 square miles.
Despite being classified as a high hazard potential dam, Granite Lake Dam is currently assessed to be in fair condition, with the last inspection conducted in April 2019. The dam features an uncontrolled spillway with a width of 12 feet and poses moderate risk, as per the risk assessment rating. Managed by the NHDES Dam Bureau, this local government-owned dam is subject to state regulation, inspection, and enforcement, ensuring its safety and compliance with necessary protocols.
With its picturesque location and contribution to the local recreational scene, Granite Lake Dam serves as an important water resource in the region. As water resource and climate enthusiasts, understanding the significance of structures like Granite Lake Dam is crucial for appreciating their role in providing not just leisure opportunities but also in ensuring water safety and management for the community.
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 Granite Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Ashuelot River Near Gilsum | 156 cfs | → |
| Otter Brook Below Otter Brook Dam | 12 cfs | → |
| Ashuelot River Below Surry Mt Dam | 317 cfs | → |
| Ashuelot River Above The Branch | 21 cfs | → |
| North Branch River Near Antrim | 61 cfs | → |
| S Br Ashuelot River At Webb | 25 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Granite Lake Dam.
Boat launches
- Granite Lake Boat Launch
- Center Pond Boat Launch
- Bolster Pond Boat Launch
- Chapman Pond Boat Launch
- Island Pond Boat Launch
Campgrounds
- Fox Brook Tent Site
- Wheelock Park Campground
- Camp Wanocksett
- Mt Monadnock State Park Campground
- Pilgrim Pines Camping Area
- Swanzey Lake Camping Area
Paddle runs
- First Bridge Upstream On Route 100 To Confluence With West River
- Headwaters To First Bridge Upstream On Route 100
- Sewall's Island To Manchester Street Bridge
- Headwaters To Confluence With West River (End Of Sherman Road)
- Headwaters To Crossing Of Route 100 Near Route 155
- Begins In Franklin To Sewall's Island
Track Granite 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 Granite Lake Dam
Where does the data for Granite 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 Granite Lake Dam.