Lake Edwin Johnson Dam Reservoir Report

Last Updated: December 5, 2025

Lake Edwin Johnson Dam, located in Spartanburg, South Carolina, is a state-owned earth dam completed in 1942 with a primary purpose of recreation.


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Summary

Standing at a height of 36 feet and stretching 400 feet in length, the dam holds a maximum storage capacity of 570 acre-feet, with a normal storage level of 420 acre-feet. The dam is situated on Thompson Creek and covers a surface area of 38 acres, offering a picturesque setting for water resource and climate enthusiasts.

Despite its recreational appeal, Lake Edwin Johnson Dam poses a significant hazard potential and has been assessed as unsatisfactory in condition as of March 2019. The dam is subject to state regulation, inspection, and enforcement by SC DHEC, with a required inspection frequency of every three years. While the dam has no spillway or outlet gates, its construction with stone core types on a soil foundation highlights the engineering challenges faced in maintaining this vital water resource infrastructure.

As a beloved spot for outdoor activities and water-based recreation, Lake Edwin Johnson Dam serves as a reminder of the importance of effective dam management and emergency preparedness. With its rich history and scenic surroundings, the dam stands as a testament to the enduring need for sustainable water resource practices in the face of changing climate patterns.

Year Completed

1942

Dam Length

400

Dam Height

36

River Or Stream

THOMPSON CREEK

Primary Dam Type

Earth

Surface Area

38

Nid Storage

570

Hazard Potential

Significant

Foundations

Soil

Nid Height

36
       
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.