Grindstone-Lost-Muddy Watershed Dam A-33 Reservoir Report
Last Updated: December 5, 2025
Located in DeKalb County, Missouri, the Grindstone-Lost-Muddy Watershed Dam A-33, also known as Grindstn Lost-Muddy-Cr Wrsd Dm A-33, was completed in 1969 by the USDA NRCS for the purpose of grade stabilization along TR-GRINDSTONE CREEK.
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Summary
This earth dam stands at a height of 27 feet and stretches 470 feet in length, with a storage capacity of 119 acre-feet and a drainage area of 268.8 square miles. The dam has a low hazard potential and is currently not rated for its condition assessment.
Despite not being regulated by the state and lacking inspection, permitting, and enforcement processes, the dam's purpose of grade stabilization plays a crucial role in managing the flow of water in the watershed. With a moderate risk assessment, the dam serves as a vital infrastructure for the local government of PATTONSBURG, providing essential flood protection and water resource management for the surrounding area. The dam's uncontrolled spillway, with a width of 60 feet, ensures the safe discharge of excess water during heavy rainfall events, mitigating potential risks to downstream communities.
As a key feature in the Rock Island District, the Grindstone-Lost-Muddy Watershed Dam A-33 contributes to the overall water resource and climate resilience of the region. Its strategic location and design by the Natural Resources Conservation Service demonstrate a commitment to sustainable water management practices. While not currently rated for its condition, the dam's construction and functionality highlight the importance of maintaining critical infrastructure for flood control and ecosystem health in the Missouri landscape.
Year Completed |
1969 |
Dam Length |
470 |
Dam Height |
27 |
River Or Stream |
TR-GRINDSTONE CREEK |
Primary Dam Type |
Earth |
Surface Area |
8 |
Hydraulic Height |
27 |
Drainage Area |
268.8 |
Nid Storage |
119 |
Structural Height |
27 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
27 |
Seasonal Comparison
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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 Watershed Dam A-33