Upper Little Black Watershed Dam D-12 Reservoir Report

Last Updated: December 5, 2025

Upper Little Black Watershed Dam D-12, located in the picturesque city of Success Ark.


°F

°F

mph

Wind

%

Humidity

Summary

in Ripley, Missouri, is a vital piece of infrastructure designed by the USDA NRCS in 1998 for flood risk reduction along the Spell Branch to Little Black River. This earth dam stands at a height of 31 feet and has a hydraulic height of 29 feet, with a whopping 940 feet in length. Despite its grand scale, the dam boasts a low hazard potential and is not currently regulated by the state, showcasing its reliability in mitigating flood risks in the region.

With a storage capacity of 643 acre-feet, Upper Little Black Watershed Dam D-12 serves as a critical resource for the local community, providing protection against potential inundation with a maximum discharge capacity of 418 cubic feet per second. The dam's spillway, featuring an uncontrolled design with a width of 30 feet, ensures effective water flow management during periods of high precipitation. Although the dam's condition has not been recently assessed, its moderate risk rating suggests a proactive approach to risk management is essential to uphold its functionality and safeguard the surrounding environment.

As a key component of the flood risk reduction strategy in the area, Upper Little Black Watershed Dam D-12 plays a crucial role in maintaining the safety and well-being of residents in Ripley County. With its solid foundation, stone core, and strategic location, this dam stands as a testament to effective water resource management and climate resilience efforts in Missouri. Despite its unregulated status, ongoing monitoring and maintenance are essential to uphold the dam's structural integrity and ensure its continued effectiveness in mitigating flood risks in the region.

Year Completed

1998

Dam Length

940

Dam Height

31

River Or Stream

SPELL BRANCH TO LITTLE BLACK

Primary Dam Type

Earth

Surface Area

2

Hydraulic Height

29

Drainage Area

60

Nid Storage

643

Structural Height

34

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

34
       
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.