Mccollough Dam Reservoir Report
Last Updated: December 15, 2025
McCollough Dam, located in Denison, Iowa, was completed in 2000 by the USDA NRCS with a primary purpose of grade stabilization along the Tr- East Boyer River.
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Summary
This private-owned earth dam stands at a height of 28 feet and spans 458 feet in length, providing a storage capacity of 62 acre-feet for the surrounding area. The dam's spillway is uncontrolled with a width of 1 foot, and it has a low hazard potential according to the data.
With its location in Crawford County, Iowa, McCollough Dam plays a crucial role in managing water resources and protecting against potential flooding in the region. Operated by the Natural Resources Conservation Service, the dam is regulated by the Iowa DNR and undergoes regular inspections to ensure its structural integrity and functionality. Despite being rated as not assessed in terms of condition, the dam's risk assessment is moderate, highlighting the importance of ongoing risk management measures to mitigate any potential threats to the surrounding community and environment.
Year Completed |
2000 |
Dam Length |
458 |
Dam Height |
28 |
River Or Stream |
Tr- East Boyer River |
Primary Dam Type |
Earth |
Surface Area |
4.8 |
Drainage Area |
0.16 |
Nid Storage |
62 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
North Raccoon River Near Sac City
|
312cfs |
Maple River At Mapleton
|
323cfs |
Little Sioux River Near Turin
|
1040cfs |
Soldier River At Pisgah
|
112cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Boyer River At Logan
|
417cfs |
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.
Mccollough Dam