South Fork Blackwater River Dam E-21 Reservoir Report
Last Updated: December 6, 2025
South Fork Blackwater River Dam E-21, located in Holden, Missouri, serves as a Grade Stabilization structure along the TR-PIN OAK CREEK.
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Summary
Constructed in 1965 by the USDA NRCS, the earth dam stands at a height of 17 feet, with a structural height of 19 feet and a length of 940 feet. With a maximum storage capacity of 97 acre-feet and a drainage area of 729.6 acres, the dam plays a crucial role in managing water resources in the region.
Despite its low hazard potential and moderate risk assessment, South Fork Blackwater River Dam E-21 has not been rated for its condition assessment. The dam features an uncontrolled spillway with a width of 30 feet, and no outlet gates or associated structures. While the dam has not been inspected recently, its primary purpose of Grade Stabilization indicates its importance in maintaining the stability of the surrounding area. With a history of federal agency involvement from the Natural Resources Conservation Service, the dam continues to be a key component in water management efforts in Johnson County, Missouri.
As water resource and climate enthusiasts continue to monitor and assess the impact of dams like South Fork Blackwater River Dam E-21, its role in mitigating flood risks and managing water flow in the region remains crucial. With its strategic location and design, the dam exemplifies the collaborative efforts between local governments and federal agencies in safeguarding communities and ecosystems from potential water-related hazards.
Year Completed |
1965 |
Dam Length |
940 |
Dam Height |
17 |
River Or Stream |
TR-PIN OAK CREEK |
Primary Dam Type |
Earth |
Surface Area |
1 |
Hydraulic Height |
17 |
Drainage Area |
729.6 |
Nid Storage |
97 |
Structural Height |
19 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
19 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
South Fork Blackwater River Dam E-21