Lake Cohoon Dam Reservoir Report

Last Updated: December 21, 2025

Lake Cohoon Dam in Suffolk, Virginia, is a crucial water supply infrastructure managed by the local government.


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Summary

This earth dam, standing at a height of 28.8 feet, impounds Cohoon Creek to create a reservoir with a storage capacity of 9,300 acre-feet. The dam has a surface area of 602 acres and serves the primary purpose of water supply for the surrounding area.

Despite its importance, Lake Cohoon Dam is classified as having a high hazard potential and poor condition assessment. The dam's spillway is uncontrolled with a width of 410 feet, and it has not been modified in recent years. Regular inspections are conducted, with the last assessment taking place in April 2021, highlighting the need for ongoing maintenance and risk management measures to ensure the safety and reliability of the structure.

With its location in a moderate-risk area, Lake Cohoon Dam remains a critical piece of infrastructure that requires attention and investment to address its current condition and mitigate potential hazards. Climate and water resource enthusiasts are encouraged to monitor updates on the dam's maintenance and risk management efforts to ensure the continued safety and functionality of this vital water supply facility.

Dam Length

625

Dam Height

28.8

River Or Stream

COHOON CREEK

Primary Dam Type

Earth

Surface Area

602

Drainage Area

33.83

Nid Storage

9300

Outlet Gates

Uncontrolled - 0

Hazard Potential

High

Nid Height

29
       
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.