Blockton Watershed Site A-3 Reservoir Report
Last Updated: December 13, 2025
Blockton Watershed Site A-3, located in Taylor County, Iowa, is a low-hazard earth dam completed in 1966 for fire protection, stock, and small fish pond purposes.
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Summary
Managed by the local government with oversight from the Iowa Department of Natural Resources, this dam has a storage capacity of 171 acre-feet and a surface area of 10.5 acres. Positioned along the TR-Platte Branch river, this site plays a crucial role in flood risk reduction for the surrounding area.
Designed by the USDA NRCS, Blockton Watershed Site A-3 has a relatively low hazard potential and a moderate risk assessment rating. With a drainage area of 0.82 square miles, this dam serves as a vital resource for water management in the region. While the condition assessment is currently not rated, regular inspections and enforcement by state regulatory agencies ensure the safety and functionality of the structure for the community.
As a part of the Rock Island District and under the jurisdiction of the Iowa DNR, Blockton Watershed Site A-3 exemplifies the collaboration between federal, state, and local entities in managing water resources. With its primary purpose of fire protection and flood risk reduction, this site serves as a significant asset for the community of Sheridan, MO, and the broader Taylor County area in Iowa.
Year Completed |
1966 |
Dam Length |
579 |
Dam Height |
23 |
River Or Stream |
TR-PLATTE BRANCH |
Primary Dam Type |
Earth |
Surface Area |
10.5 |
Drainage Area |
0.82 |
Nid Storage |
171 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
23 |
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.
Blockton Watershed Site A-3