Nystrom Lake Dam Reservoir Report

Last Updated: December 13, 2025

Nystrom Lake Dam, located in Henry, Illinois, was completed in 1950 and is primarily used for recreation and water supply purposes.


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Summary

The dam, designed by USDA NRCS, is classified as an Earth dam with a height of 28 feet and a length of 176 feet. It has a storage capacity of 58 acre-feet and a hazard potential rated as low, with a moderate risk assessment score of 3.

The dam is state-regulated by the Illinois Department of Natural Resources, with regular inspections and enforcement measures in place. While the condition assessment is not available, the dam is considered to meet safety guidelines, although no Emergency Action Plan (EAP) has been prepared or updated. The spillway type is uncontrolled, with a width of 13 feet, and the outlet gates are also uncontrolled.

Overall, Nystrom Lake Dam serves as an important resource for the surrounding community and offers opportunities for recreation and water supply. With its moderate risk assessment and low hazard potential, the dam continues to be a key structure in managing water resources in the area.

Year Completed

1950

Dam Length

176

Dam Height

28

River Or Stream

TRIB SOUTH EDWARDS RIVER

Primary Dam Type

Earth

Nid Storage

58

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

28
       
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.