Long Pond Reservoir Report

Last Updated: December 6, 2025

Long Pond in Rhode Island is a gravity dam completed in 1885, standing at a height of 10 feet and holding a maximum storage capacity of 79 acre-feet.


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Summary

The dam, located in Hopkinton, serves various purposes and is primarily owned by the state. It is situated on the Blue Pond Brook and covers a surface area of 22 acres with a drainage area of 1 square mile.

Despite its historical significance, Long Pond's condition assessment is rated as poor and it has a low hazard potential. With a normal storage capacity of 62 acre-feet, the dam poses minimal risk, although its maintenance and inspection need improvement. The structure, with a length of 230 feet and a hydraulic height of 7 feet, plays a crucial role in the local water resource management, particularly in regulating water flow and providing recreational opportunities for the community.

Water resource and climate enthusiasts can appreciate Long Pond not only for its engineering marvel but also for its ecological value and recreational significance. As the dam continues to stand the test of time, stakeholders may need to address its poor condition and ensure regular inspections to maintain its safety and functionality for future generations.

Year Completed

1885

Dam Length

230

Dam Height

9

River Or Stream

BLUE POND BROOK

Primary Dam Type

Gravity

Surface Area

22

Hydraulic Height

7

Drainage Area

1

Nid Storage

79

Structural Height

10

Hazard Potential

Low

Nid Height

10
       
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.