Souhegan River Site 35 Dam dam
Souhegan River Site 35 Dam
Souhegan River Site 35 Dam, also known as Smithville Dam, is a state-owned structure located in New Ipswich, Hillsborough County, New Hampshire. Built in 1965 by the USDA NRCS, this Earth-type dam stands at 30 feet high and spans 1209 feet along the West Branch Souhegan River. Its primary purpose is flood risk reduction, with a storage capacity of 1787 acre-feet and a drainage area of 6.4 square miles.
The dam's hazard potential is classified as high, but its condition assessment as of April 2018 was deemed satisfactory. It is regularly inspected by the NHDES DAM BUREAU, with the last inspection conducted in September 2020. Despite its moderate risk level, the dam has no emergency action plan (EAP) in place, and its risk management measures and inundation maps are currently unprepared. With a maximum discharge capacity of 9135 cubic feet per second, the dam plays a crucial role in managing water flow in the area and protecting downstream communities from flooding events.
Overall, Souhegan River Site 35 Dam serves as a vital piece of infrastructure for flood control along the West Branch Souhegan River. While it faces certain risks and challenges, such as its high hazard potential and lack of an EAP, the dam's satisfactory condition and regular inspections ensure that it continues to fulfill its primary purpose effectively. Its presence highlights the importance of proper dam management and the need for comprehensive emergency preparedness measures to safeguard surrounding areas and communities from potential water-related disasters.
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 Souhegan River Site 35 Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Contoocook River At Peterborough | 118 cfs | → |
| Millers River Near Winchendon | 121 cfs | → |
| Souhegan River (Site Wlr-1) Near Milford | 181 cfs | → |
| North Nashua River At Fitchburg | 101 cfs | → |
| Nubanusit Bk Blw Macdowell Dam Nr Peterborough Nh | 31 cfs | → |
| Priest Brook Near Winchendon | 33 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Souhegan River Site 35 Dam.
Boat launches
- Grassy Pond Boat Launch
- Contoocook Lake Boat Launch
- Cunningham Pond Boat Launch
- Pool Pond Boat Launch
- Frost Pond Boat Launch
- Melendy Pond Boat Launch
Campgrounds
- Damon Pond Campground
- Pearl Hill Campground
- Lake Dennison State Park
- East Dennison Camping Area
- North Dennison Camping Area
- Otter River State Forest
Track Souhegan River Site 35 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 Souhegan River Site 35 Dam
Where does the data for Souhegan River Site 35 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 Souhegan River Site 35 Dam.