Little Cohas Brook Dam dam
Little Cohas Brook Dam
Little Cohas Brook Dam, located in Londonderry, New Hampshire, is a concrete structure built in 1953 primarily for recreational purposes. Standing at a height of 10 feet and stretching 70 feet in length, this dam has a storage capacity of 867 acre-feet and serves as a picturesque spot for outdoor activities. The dam overlooks the serene Little Cohas Brook, which has a drainage area of 6.59 square miles and a maximum discharge of 1011 cubic feet per second.
Managed by the NHDES Dam Bureau, this dam has a low hazard potential and fair condition assessment. With a spillway width of 45 feet and uncontrolled spillway type, Little Cohas Brook Dam poses a moderate risk, but this risk is effectively managed through regular inspections and enforcement by the state regulatory agency. The surrounding area offers a surface area of 17 acres for recreational use, making it a popular destination for water resource and climate enthusiasts seeking a tranquil escape in Rockingham County, New Hampshire.
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 Little Cohas Brook Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Merrimack R Nr Goffs Falls | 8,350 cfs | → |
| Souhegan River At Merrimack | 235 cfs | → |
| Piscataquog River Near Goffstown | 137 cfs | → |
| Beaver Brook At North Pelham | 31 cfs | → |
| Spicket River At North Salem | 0 cfs | → |
| South Branch Piscataquog River Near Goffstown | 127 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Little Cohas Brook Dam.
Boat launches
- Heritage Trail Bedford
- Scobie Pond Boat Launch
- Beaver Lake Boat Launch
- Massabesic Lake Boat Launch
- Kendall Pond Boat Launch
Campgrounds
- Windham Town Forest Tent Platforms
- Remote Campsite
- Saddleback Campground
- Grotonwood
- Camp Spaulding
- Pearl Hill Campground
Paddle runs
Track Little Cohas Brook 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 Little Cohas Brook Dam
Where does the data for Little Cohas Brook 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 Little Cohas Brook Dam.