Grindstone-Lost-Muddy A-8 Dam Reservoir Report
Last Updated: December 5, 2025
Located in Pattonsburg, Missouri, the Grindstone-Lost-Muddy A-8 Dam is a vital piece of infrastructure designed by the USDA NRCS in 1985 for flood risk reduction along the tributary of Grindstone Creek.
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Summary
Standing at a height of 39 feet with a length of 450 feet, this earth dam plays a crucial role in safeguarding the surrounding area from potential flooding events.
With a storage capacity of 85 acre-feet and a drainage area of 884 square miles, the dam has a low hazard potential and is deemed to be in satisfactory condition. It features an uncontrolled spillway with a width of 60 feet and a slide (sluice gate) outlet gate. Despite its moderate risk assessment, the dam has not been modified in recent years and is inspected every 5 years to ensure its continued effectiveness in flood risk reduction.
Managed by the local government and regulated by the DAM AND RESERVOIR SAFETY PROG, the Grindstone-Lost-Muddy A-8 Dam serves as a beacon of resilience in the face of climate challenges. Water resource and climate enthusiasts can appreciate the strategic design and engineering behind this essential structure, which plays a critical role in protecting the community and environment from the impacts of potential flooding events.
Year Completed |
1985 |
Dam Length |
450 |
Dam Height |
37 |
River Or Stream |
TRIB GRINDSTONE CREEK |
Primary Dam Type |
Earth |
Surface Area |
11 |
Drainage Area |
884 |
Nid Storage |
85 |
Structural Height |
39 |
Outlet Gates |
Slide (sluice gate) |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
39 |
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.
Grindstone-Lost-Muddy A-8 Dam