Upper Little Black Watershed Dam D- 7 Reservoir Report

Last Updated: December 5, 2025

Upper Little Black Watershed Dam D-7, also known as Site D-7, is a local government-owned Earth dam located in Naylor, Missouri.


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Summary

Designed by the USDA NRCS and completed in 1990, this dam serves the primary purpose of flood risk reduction along the Last Chance Hollow stream. With a height of 34.8 feet and a length of 700 feet, the dam has a maximum storage capacity of 429 acre-feet and a normal storage capacity of 106 acre-feet, covering a surface area of 15 acres and draining a watershed area of 1025 acres.

Despite its low hazard potential and moderate risk assessment, Upper Little Black Watershed Dam D-7 has not been inspected since July 1993 and is currently not rated in terms of condition assessment. The dam features an uncontrolled spillway with a width of 30 feet and no outlet gates. While it lacks regular state regulation, inspection, and enforcement, the dam remains crucial for managing flood risk in the region. As a key structure in the local water resource management system, its maintenance and monitoring are essential for ensuring the safety and integrity of the surrounding communities and ecosystems in Ripley County, Missouri.

Year Completed

1990

Dam Length

700

Dam Height

34.8

River Or Stream

LAST CHANCE HOLLOW

Primary Dam Type

Earth

Surface Area

15

Hydraulic Height

32

Drainage Area

1025

Nid Storage

429

Structural Height

44

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

44
       
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.