Block Dam Reservoir Report
Last Updated: December 13, 2025
Block Dam, located in Crawford County, Iowa, is a private earth dam completed in 1967 with a primary purpose of fire protection, stock, or small fish pond.
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Summary
Managed by the USDA NRCS, this low hazard potential dam stands at 34 feet tall and spans 524 feet in length, with a storage capacity of 100 acre-feet. Serving the TR-Buck Run river/stream, Block Dam is state-regulated by the Iowa DNR, with permitting, inspection, and enforcement in place to ensure its safety and functionality.
Despite its moderate risk assessment, Block Dam has not been rated for condition assessment, and no emergency action plan (EAP) has been prepared. With a surface area of 5 acres and a drainage area of 0.5 square miles, this dam plays a crucial role in the local ecosystem and water resource management. While the spillway type is listed as uncontrolled, the dam's design and construction reflect a commitment to preserving the surrounding environment while meeting the needs of fire protection and stock pond purposes.
As a key structure in the Rock Island District, Block Dam's presence highlights the intersection of water resource management, climate resilience, and agricultural practices in the region. With ongoing monitoring and regulation by state authorities, this dam serves as a vital component in the sustainable development and conservation of water resources in Crawford County, Iowa.
Year Completed |
1967 |
Dam Length |
524 |
Dam Height |
34 |
River Or Stream |
TR-BUCK RUN |
Primary Dam Type |
Earth |
Surface Area |
5 |
Drainage Area |
0.5 |
Nid Storage |
100 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
34 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Boyer River At Logan
|
417cfs |
Maple River At Mapleton
|
323cfs |
Soldier River At Pisgah
|
112cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
West Nishnabotna River At Hancock
|
154cfs |
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.
Block Dam