Black Hawk Marsh Dam Reservoir Report
Last Updated: December 13, 2025
Black Hawk Marsh Dam, located in Black Hawk Lake, Iowa, is a state-regulated dam with a primary purpose of recreation.
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Summary
Constructed in 1994, this earth dam stands at a height of 8 feet and spans a length of 8150 feet. With a storage capacity of 1200 acre-feet and a surface area of 214 acres, Black Hawk Marsh Dam plays a crucial role in the management of the Carnavon Creek drainage system.
Managed by the Iowa Department of Natural Resources, Black Hawk Marsh Dam is designed to withstand low hazard potential and has not been rated for its condition assessment. Despite its moderate risk rating, the dam has not been inspected recently, and emergency preparedness measures such as an Emergency Action Plan have not been documented. With a focus on recreation and a relatively small drainage area of 12.3 square miles, Black Hawk Marsh Dam serves as a vital water resource for the community while offering opportunities for outdoor activities in the picturesque setting of Black Hawk Lake.
Year Completed |
1994 |
Dam Length |
8150 |
Dam Height |
8 |
River Or Stream |
CARNAVON CREEK DRAINAGE |
Primary Dam Type |
Earth |
Surface Area |
214 |
Drainage Area |
12.3 |
Nid Storage |
1200 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
8 |
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.
Black Hawk Marsh Dam
Black Hawk Lake At Lake View