Old Blowing Rock Water Supply Reservoir Report

Last Updated: December 5, 2025

Old Blowing Rock Water Supply is a crucial water resource in Boone, North Carolina, serving as a primary source of water supply for the local community.


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Summary

The dam, completed in 1958, stands at a hydraulic height of 32.3 feet and a structural height of 33.5 feet, with a storage capacity of 76 acre-feet. Situated on Flat Top Branch, the dam plays a vital role in managing water resources in the region, with a normal storage capacity of 61 acre-feet and a drainage area of 340 acres.

Owned by the local government and regulated by the North Carolina Dam Safety Program, Old Blowing Rock Water Supply is classified as a high hazard potential dam. Despite its high hazard potential, the dam is in satisfactory condition, as per the latest inspection in March 2021. With a spillway type not specified and a maximum discharge capacity of 725 cubic feet per second, the dam is equipped to handle varying water flow conditions and ensure the safety of the surrounding area. Overall, Old Blowing Rock Water Supply is a critical infrastructure for water resource management and climate resilience in Watauga County.

With Virginia Foxx as the representative for the congressional district, Old Blowing Rock Water Supply exemplifies the intersection of infrastructure, governance, and environmental stewardship. As a state-regulated and permitted dam with a history of safe operations, the facility underscores the importance of proactive monitoring and maintenance in ensuring water security and mitigating potential risks. As water resource and climate enthusiasts, understanding the role of dams like Old Blowing Rock Water Supply is key to advancing sustainable water management practices and building resilience in the face of changing climatic conditions.

Year Completed

1958

Dam Length

325

River Or Stream

Flat Top Branch

Primary Dam Type

Earth

Surface Area

5.7

Hydraulic Height

32.3

Drainage Area

340

Nid Storage

76

Structural Height

33.5

Hazard Potential

High

Nid Height

34
       
Seasonal Comparison

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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.