Holiday Lake Dam Reservoir Report

Last Updated: December 6, 2025

Holiday Lake Dam, located in Marengo, Iowa, serves as a recreational hub along the tranquil waters of TR-Walnut Creek.


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Summary

Built in 1962, this earth dam stands at 50 feet high, with a length of 1,205 feet, creating a reservoir with a storage capacity of 2,100 acre-feet. The dam's primary purpose is recreation, offering visitors a surface area of 96.5 acres to enjoy various water activities.

Managed by private owners, Holiday Lake Dam is regulated by the Iowa Department of Natural Resources, ensuring its compliance with state inspection, permitting, and enforcement requirements. Despite its significant hazard potential, the dam has been deemed to be in satisfactory condition during its last assessment in July 2016. With a moderate risk rating, the dam stands as a vital structure for water resource and climate enthusiasts to explore and appreciate in the heart of Poweshiek County, Iowa.

Holiday Lake Dam's picturesque setting, combined with its historical significance and recreational amenities, makes it a must-visit destination for water resource and climate enthusiasts. As one of Iowa's regulated dams, it stands as a symbol of responsible water management, offering a safe and enjoyable environment for visitors to appreciate the beauty and importance of our natural water resources. Whether you're looking to relax by the waterside or learn more about dam infrastructure, Holiday Lake Dam provides a captivating experience for all who appreciate the intersection of water conservation and outdoor recreation.

Year Completed

1962

Dam Length

1205

Dam Height

50

River Or Stream

TR-WALNUT CREEK

Primary Dam Type

Earth

Surface Area

96.5

Drainage Area

1.73

Nid Storage

2100

Hazard Potential

Significant

Foundations

Soil

Nid Height

50
       
Seasonal Comparison

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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.