Purity Lake Dam Dam
Purity Lake Dam
Purity Lake Dam, located in Madison, New Hampshire, serves as a recreational resource for visitors to the area. Built in 1750, this earth dam stands at a height of 13.2 feet and has a storage capacity of 182 acre-feet, making it an essential feature of the surrounding landscape. The dam regulates the flow of water from the Danforth Ponds, providing opportunities for boating, fishing, and other water-based activities.
Despite its historical significance and recreational value, Purity Lake Dam is classified as having a high hazard potential and poor condition assessment. The last inspection in June 2020 revealed the need for improvement in maintenance and safety measures. With a moderate risk assessment rating, it is crucial for the dam's owners to prioritize risk management measures to ensure the safety of the surrounding community and maintain the dam's functionality for future generations. Additionally, the dam is regulated by the New Hampshire Department of Environmental Services Dam Bureau, indicating a commitment to monitoring and oversight to address potential issues proactively.
For water resource and climate enthusiasts, Purity Lake Dam represents both a historical landmark and a critical piece of infrastructure for recreational purposes. Its location in a picturesque setting in Carroll County, New Hampshire, offers a unique opportunity to appreciate the intersection of human engineering with natural beauty. As efforts continue to address the dam's maintenance needs and ensure its long-term viability, stakeholders can work together to preserve this valuable resource for the enjoyment of all who visit the area.
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 Purity Lake Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Saco River Near Conway | 306 cfs | → |
| Bearcamp River At South Tamworth | 17 cfs | → |
| Saco River At Cornish | 997 cfs | → |
| Pemigewasset River At Woodstock | 147 cfs | → |
| Pemigewasset River At Plymouth | 277 cfs | → |
| East Branch Pemigewasset River At Lincoln | 113 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Purity Lake Dam.
Boat launches
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Campgrounds
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River runs
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More reservoirs
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About Purity Lake Dam
Where does the data for Purity 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 below 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.
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.