Lake Nelson Dam Reservoir Report

Last Updated: December 15, 2025

Lake Nelson Dam, located in Petersville, Illinois, stands as a testament to engineering prowess and environmental stewardship.


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Summary

Completed in 1937, this earth dam spans 300 feet in length and reaches a height of 14 feet, providing essential storage capacity of 65 acre-feet for the surrounding area. Managed by a private entity, the dam serves multiple purposes, including recreation and water resource management.

Despite its low hazard potential, Lake Nelson Dam remains under the regulatory oversight of the Illinois Department of Natural Resources, ensuring regular inspections and enforcement of safety measures. With a moderate risk assessment rating, stakeholders are actively engaged in risk management strategies to safeguard the dam and surrounding communities. The dam's uncontrolled spillway and outlet gates further highlight the need for diligent monitoring and emergency preparedness.

With its picturesque location along Trib Eliza Creek, Lake Nelson Dam offers not only a tranquil recreational spot but also a vital component of the region's water infrastructure. As climate change continues to impact water resources, the proactive approach to dam safety and management at Lake Nelson sets a shining example for sustainable water resource practices in the face of evolving environmental challenges.

Year Completed

1937

Dam Length

300

Dam Height

14

River Or Stream

TRIB ELIZA CREEK

Primary Dam Type

Earth

Nid Storage

65

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

14
       
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.