Izzak Walton League Dam Reservoir Report

Last Updated: December 6, 2025

The Izzak Walton League Dam, located in Ottumwa, Iowa, along the TR-Sugar Creek river, was completed in 1965 for the primary purpose of recreation.


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Summary

This earth dam, designed by the USDA NRCS, stands at a height of 35 feet and spans 420 feet, with a storage capacity of 191 acre-feet. The dam is owned privately and regulated by the Iowa DNR, with state permitting, inspection, and enforcement in place to ensure its safety and compliance with regulations.

Despite its recreational significance, the Izzak Walton League Dam is classified as having a significant hazard potential and a poor condition assessment. The last inspection in June 2019 highlighted these concerns, prompting a moderate risk assessment rating. While the dam does not have an Emergency Action Plan in place, efforts may be needed to improve its condition and reduce risks associated with its operation. With its beautiful location and potential for water resource management, the future of the Izzak Walton League Dam will likely involve ongoing monitoring and maintenance to ensure its continued safety and functionality for the community.

Year Completed

1965

Dam Length

420

Dam Height

35

River Or Stream

TR-SUGAR CREEK

Primary Dam Type

Earth

Surface Area

10.8

Drainage Area

0.39

Nid Storage

191

Hazard Potential

Significant

Foundations

Soil

Nid Height

35
       
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.