Number One Pond dam
Number One Pond
Number One Pond, located in Sanford, Maine, is a concrete gravity dam completed in 1912 primarily for flood risk reduction along the Mousam River. With a structural height of 14 feet and a length of 245 feet, the dam has a maximum storage capacity of 508 acre-feet and a normal storage capacity of 278 acre-feet, covering a surface area of 45 acres and draining an area of 41 square miles. The dam's spillway width is 185 feet, and it has been assessed to have a low hazard potential and fair condition as of the last inspection in October 2011.
Owned by the local government and regulated by the Maine Emergency Management Agency (MEMA), Number One Pond serves multiple purposes including flood risk reduction, recreation, and other uses. The dam has state permitting, inspection, and enforcement in place, ensuring its continued safety and functionality. The emergency action plan (EAP) for the dam was last revised in May 2018, but specific details on its compliance with guidelines and risk management measures are not available. Despite its age, Number One Pond Dam remains a vital infrastructure for water resource management in the area, contributing to the overall resilience of the community against flood events.
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 Number One Pond -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mousam River Near West Kennebunk | 267 cfs | → |
| Cocheco River Near Rochester | 117 cfs | → |
| Isinglass R At Rochester Neck Rd | 66 cfs | → |
| Oyster River Near Durham | 13 cfs | → |
| Lamprey River Near Newmarket | 137 cfs | → |
| Saco River At Cornish | 7,900 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Number One Pond.
Boat launches
- Emery Mills Road 125, Shapleigh
- West Shore Road 411, Acton
- Norton Ridge Road 99, Shapleigh
- Lovell Lake Road 3198, Acton
- Great East Lake Boat Launch
- Landing Road 8, Buxton
Campgrounds
- Ferry Beach Campground
- Old Stage Campground
- Wild Duck Campground & Rv Park
- Bayley's Camping Resort
- Green Tops Campground
- Saddleback Campground
Track Number One Pond 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 Number One Pond
Where does the data for Number One Pond 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 Number One Pond.