Summary
With a dam height of 22 feet and a length of over 1000 feet, this multi-purpose dam has a storage capacity of 130,738 acre-feet, providing essential water resources for the area. The dam's controlled spillway and 20 slide gates ensure efficient water management and flood control, making it a critical infrastructure for sustainable water resource management.
Managed by the Federal Energy Regulatory Commission, Middle Dam is designed with a combination of buttress, earth, and rockfill materials, supported by roller-compacted concrete core types. Its hazard potential is classified as high, with a very high risk assessment rating of 1, emphasizing the importance of regular inspections and emergency preparedness. Despite its age, Middle Dam continues to play a crucial role in balancing water supply, hydropower generation, and environmental conservation efforts in the region, highlighting the intersection of water resource management and climate resilience at this historic site.
Year Completed |
1883 |
Dam Length |
1004 |
Dam Height |
22 |
River Or Stream |
Rapid River |
Surface Area |
7470 |
Drainage Area |
472 |
Nid Storage |
130738 |
Outlet Gates |
Slide (sluice gate) - 20 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
22 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Diamond River Near Wentworth Location
|
126cfs |
Androscoggin River At Errol
|
1500cfs |
Ellis River At South Andover
|
74cfs |
Swift River Near Roxbury
|
89cfs |
Androscoggin River At Rumford
|
2230cfs |
Wild River At Gilead
|
100cfs |
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.
R21
R22
R26
R23
R24
R34
Middle Dam