Harwood's Mill Dam Reservoir Report

Last Updated: December 21, 2025

Harwood's Mill Dam, located in York, Virginia, is a crucial structure for water supply purposes, standing at a height of 27 feet and spanning a length of 1200 feet.


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Summary

Completed in 1919, the dam holds a storage capacity of 5845 acre-feet, with a normal storage level of 2696 acre-feet. The dam is situated on the Poquoson River and is regulated by the Department of Conservation and Recreation in Virginia.

Despite its historic significance, Harwood's Mill Dam is currently rated as having a high hazard potential and poor condition, as assessed during the last inspection in October 2020. The dam's emergency action plan (EAP) was last revised in August 2016, highlighting the need for updated risk management measures and guidelines to ensure the safety and integrity of the structure. With its critical role in water supply infrastructure, stakeholders and enthusiasts in water resource and climate fields should closely monitor the ongoing maintenance and regulatory oversight of Harwood's Mill Dam to mitigate potential risks and ensure its long-term resilience.

Year Completed

1919

Dam Length

1200

Dam Height

27

River Or Stream

POQUOSON RIVER

Primary Dam Type

Earth

Surface Area

274

Hydraulic Height

27

Nid Storage

5845

Structural Height

27

Hazard Potential

High

Nid Height

27
       
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.