Sanborn Sawmill Dam Reservoir Report
Last Updated: December 17, 2025
Sanborn Sawmill Dam, located in Loudon, New Hampshire, was completed in 1830 and serves multiple purposes including fire protection and creating a small fish pond.
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Summary
The dam, primarily made of earth with a buttress core type, stands at a height of 13 feet and spans a length of 156 feet. It has a storage capacity of 2.5 acre-feet and covers a surface area of 0.32 acres, with a drainage area of 4.7 acres.
Managed by the NHDES Dam Bureau, the dam is classified as state-regulated, with inspections conducted regularly to ensure its structural integrity. Despite being rated with a high hazard potential, the condition assessment in 2017 deemed it as satisfactory. The spillway type is marked as uncontrolled, with a maximum discharge capacity of 565 cubic feet per second. The risk assessment for the dam is moderate, with measures for risk management yet to be specified.
For water resource and climate enthusiasts, the Sanborn Sawmill Dam presents an intriguing case study in dam management and maintenance. With its historical significance and ecological impact on the Sanborn Brook, monitoring its condition and risk assessment becomes crucial for ensuring the safety of surrounding communities and wildlife. The collaborative efforts between private ownership and state regulatory agencies underscore the importance of sustainable water resource management in the face of evolving climate challenges.
Year Completed |
1830 |
Dam Length |
156 |
Dam Height |
13 |
River Or Stream |
SANBORN BROOK |
Primary Dam Type |
Earth |
Surface Area |
0.32 |
Drainage Area |
4.7 |
Nid Storage |
2.5 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
13 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Suncook River At North Chichester
|
62cfs |
Soucook River
|
22cfs |
Winnipesaukee River At Tilton
|
85cfs |
Merrimack River At Franklin Junction
|
857cfs |
Blackwater River Near Webster
|
19cfs |
Warner River At Davisville
|
50cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
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. Investigations and studies are necessary.
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.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams 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, environment 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.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Sanborn Sawmill Dam
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