Silver Lake Dam Reservoir Report

Last Updated: December 24, 2025

Silver Lake Dam, located in Harrisville, New Hampshire, stands as a vital water resource and recreational hub in the region.


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Summary

Built in 1924, this earth dam spans 80 feet in length and reaches a height of 12 feet, holding a maximum storage capacity of 4,070 acre-feet. Serving primarily for recreation, the dam overlooks the picturesque Minnewawa Brook and offers a surface area of 341 acres for visitors to enjoy various water activities.

Managed by the New Hampshire Department of Environmental Services Dam Bureau, Silver Lake Dam has been deemed to have a low hazard potential with a satisfactory condition assessment as of October 2012. The dam's spillway, an uncontrolled type with a width of 11 feet, can withstand a maximum discharge of 228 cubic feet per second. Despite its moderate risk assessment level, regular inspections every six years ensure the dam's safety measures are up-to-date, providing a sense of security for the surrounding community and visitors alike.

With its rich history, scenic beauty, and vital role in water resource management, Silver Lake Dam remains a significant landmark in Cheshire County, New Hampshire. Its strategic location, combined with its recreational value and low hazard potential, underscores the importance of ongoing monitoring and maintenance to preserve both the dam's structural integrity and the natural ecosystem it supports along Minnewawa Brook.

Year Completed

1924

Dam Length

80

Dam Height

12

River Or Stream

MINNEWAWA BROOK

Primary Dam Type

Earth

Surface Area

341

Drainage Area

2.4

Nid Storage

4070

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

12
       
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.