Sunapee Reservoir Report

Last Updated: December 14, 2025

Sunapee, also known as River Road Dam or Sugar River Dam, is a picturesque masonry dam located in Newport, New Hampshire.


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Summary

Built in 1856, this historic structure serves a primary purpose of generating hydroelectric power from the Sugar River. With a height of 15 feet and a length of 71 feet, Sunapee has a storage capacity of 5 acre-feet and a maximum discharge of 600 cubic feet per second.

Managed by the local government and regulated by the New Hampshire Department of Environmental Services Dam Bureau, Sunapee is also under the oversight of the Federal Energy Regulatory Commission. Despite being classified as having a significant hazard potential, the dam's condition assessment is currently unavailable. However, regular inspections are conducted to ensure its safety and functionality. In case of emergencies, an emergency action plan is in place, although the last revision dates back to 2005.

For water resource and climate enthusiasts, Sunapee presents a fascinating blend of history, engineering, and environmental stewardship. As a vital component of the local hydroelectric infrastructure, this dam plays a crucial role in harnessing renewable energy from the Sugar River. Its location in the scenic Sullivan County offers a unique opportunity to appreciate the intersection of human ingenuity and natural resources. Despite the potential risks associated with its operation, Sunapee stands as a testament to the sustainable utilization of water resources for the benefit of the community.

Year Completed

1856

Dam Length

71

Dam Height

15

River Or Stream

Sugar River

Primary Dam Type

Masonry

Surface Area

1

Drainage Area

45

Nid Storage

5

Outlet Gates

Slide (sluice gate) - 1

Hazard Potential

Significant

Nid Height

15
       
Seasonal Comparison

Weather Forecast

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. 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

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, 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.