Henningsgaard Dam Reservoir Report

Last Updated: December 5, 2025

Located in Decorah, Iowa, the Henningsgaard Dam is a privately owned structure that serves multiple purposes including fire protection, stock maintenance, and a small fish pond.


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Summary

Constructed in 2002 by the NRCS, this earth dam stands at a height of 30 feet and spans a length of 453 feet. With a storage capacity of 203 acre-feet and a normal storage level of 50 acre-feet, the dam covers a surface area of 8.8 acres and drains a 1.89 square mile watershed.

Situated along the TR- UPPER IOWA RIVER, the Henningsgaard Dam is regulated by the Iowa Department of Natural Resources and undergoes regular inspections and enforcement to ensure its safety and compliance. With a low hazard potential and a moderate risk assessment rating, the dam poses minimal risk to the surrounding area. Despite being uncontrolled, the spillway width of 3 feet helps manage water flow during peak periods. Overall, the Henningsgaard Dam stands as an essential resource for water management and conservation in Winneshiek County, Iowa.

With its strategic location and multi-purpose functionality, the Henningsgaard Dam plays a crucial role in maintaining water resources and supporting local ecosystems in the region. As a testament to effective engineering and management practices, this structure exemplifies the importance of sustainable infrastructure development in the face of changing climate patterns and increasing water demands. As water resource and climate enthusiasts continue to advocate for responsible stewardship of natural resources, the Henningsgaard Dam stands as a model for effective water management practices in the state of Iowa.

Year Completed

2002

Dam Length

453

Dam Height

30

River Or Stream

TR- UPPER IOWA RIVER

Primary Dam Type

Earth

Surface Area

8.8

Drainage Area

1.89

Nid Storage

203

Hazard Potential

Low

Foundations

Soil

Nid Height

30
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.