Allen Reservoir Pl-566 Flood Control Dam Reservoir Report

Last Updated: December 19, 2025

The Allen Reservoir Pl-566 Flood Control Dam in Walpole, Massachusetts, stands as a crucial structure for flood risk reduction along Spring Brook.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 1980, this earth dam reaches a height of 21 feet, with a hydraulic height of 6 feet and a length of 1500 feet. With a storage capacity of 240 acre-feet, the dam serves a primary purpose of flood risk reduction, protecting the surrounding area from potential inundation during periods of heavy rainfall.

Managed by the Department of Conservation and Recreation in Massachusetts, the Allen Reservoir Dam undergoes regular inspections to ensure its structural integrity and functionality. With a hazard potential rated as high, the dam's condition assessment remains satisfactory as of the last inspection in April 2017. While the risk assessment indicates moderate risk, the dam's emergency action plan and risk management measures help mitigate potential dangers associated with its operation.

Enthusiasts of water resources and climate will find the Allen Reservoir Pl-566 Flood Control Dam a fascinating example of infrastructure designed to safeguard against flooding events. Located in Norfolk County, Massachusetts, this dam plays a crucial role in protecting the local community and surrounding areas from the impacts of high water levels, demonstrating the importance of proactive flood risk reduction measures in a changing climate.

Year Completed

1980

Dam Length

1500

Dam Height

21

River Or Stream

SPRING BROOK

Primary Dam Type

Earth

Surface Area

12.8

Hydraulic Height

6

Drainage Area

1.02

Nid Storage

240

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

21
       
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.