Portland Reservoir Dam Reservoir Report

Last Updated: December 6, 2025

The Portland Reservoir Dam, located in Portland, Connecticut, serves as a crucial water supply source for the region.


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Summary

Completed in 1964, this earth dam stands at a height of 28 feet and stretches 800 feet in length, holding a maximum storage capacity of 510 acre-feet. The dam is situated on Reservoir Brook, covering a surface area of 30.3 acres and draining an area of 3.52 square miles.

With a high hazard potential but a satisfactory condition assessment, the Portland Reservoir Dam is regulated by the Connecticut Department of Energy and Environmental Protection (DEEP) and undergoes regular inspections to ensure its safety and functionality. The dam features an uncontrolled spillway with a width of 94 feet, and while it has not been significantly modified in recent years, it remains an essential infrastructure for water resource management in the area. Overall, the Portland Reservoir Dam plays a crucial role in providing water security for the community and highlights the importance of maintaining and monitoring critical dam structures for climate resilience and emergency preparedness.

Year Completed

1964

Dam Length

800

Dam Height

28

River Or Stream

RESERVOIR BROOK

Primary Dam Type

Earth

Surface Area

30.3

Drainage Area

3.52

Nid Storage

510

Hazard Potential

High

Nid Height

28
       
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.
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Area Campgrounds

Location Reservations Toilets
Portland Reservoir DamCamp Farnam Preview Camp Farnam
Portland Reservoir DamBeech Grove 5 Preview Beech Grove 5
Portland Reservoir DamCamp Bethel Preview Camp Bethel