Henderson #1 Reservoir Report
Nearby: Henderson #2 Megunticook East
Last Updated: December 19, 2025
Henderson #1 is a privately owned earth dam located in Knox, Maine, with a primary purpose of recreation.
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Summary
Built in 1970, the dam stands at 11 feet high and has a storage capacity of 230 acre-feet. With a surface area of 25 acres and a drainage area of 0.4 square miles, Henderson #1 serves multiple purposes including fire protection, stock and small fish pond, fish and wildlife pond, and recreation.
Managed by the Maine Emergency Management Agency (MEMA), Henderson #1 is regulated by the state and undergoes regular inspections to ensure its safety and compliance with regulations. The dam has a low hazard potential and is currently rated as 'Not Rated' in terms of condition assessment. Despite not having a designated Emergency Action Plan (EAP) in place, Henderson #1 meets guidelines for risk management measures and has not experienced any major incidents or modifications in recent years.
Water resource and climate enthusiasts may find interest in Henderson #1 for its role in providing recreational opportunities while also serving practical purposes such as fire protection and wildlife conservation. Its location in Knox, Maine, offers a peaceful and scenic environment for visitors to enjoy, while its management by MEMA ensures that the dam is well-maintained and in compliance with state regulations. Overall, Henderson #1 is a valuable asset in the local ecosystem, contributing to both environmental conservation and community well-being.
Year Completed |
1970 |
Dam Length |
370 |
Dam Height |
11 |
River Or Stream |
unknown |
Primary Dam Type |
Earth |
Surface Area |
25 |
Hydraulic Height |
9 |
Drainage Area |
0.4 |
Nid Storage |
230 |
Structural Height |
11 |
Hazard Potential |
Low |
Nid Height |
11 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Henderson #1
MEGUNTICOOK LAKE