Allendale Pond Reservoir Report

Last Updated: December 6, 2025

Allendale Pond, located in Johnston, Rhode Island, is a privately owned Earth dam built in 1865 across the Woonasquatucket River.


°F

°F

mph

Wind

%

Humidity

Summary

With a hydraulic height of 12 feet and a structural height of 19 feet, this dam stands at 15 feet tall and stretches 234 feet in length. The pond has a normal storage capacity of 43 acre-feet and a maximum storage capacity of 68 acre-feet, covering a surface area of 13 acres and draining an area of 40 acres.

Despite its historical significance, Allendale Pond is currently assessed as being in poor condition with a low hazard potential. The last inspection in May 2018 revealed the need for improvements, and the dam is not under any state permitting or enforcement regulations. While the pond does have an emergency action plan, its effectiveness and adherence to guidelines are unclear. The risk assessment and management measures for this water resource are also lacking, indicating a need for further attention to ensure the safety and sustainability of Allendale Pond for both the environment and surrounding communities.

Year Completed

1865

Dam Length

234

Dam Height

15

River Or Stream

WOONASQUATUCKET RIVER

Primary Dam Type

Earth

Surface Area

13

Hydraulic Height

12

Drainage Area

40

Nid Storage

68

Structural Height

19

Hazard Potential

Low

Nid Height

19
       
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.