Harrisburg Reservoir Dam Reservoir Report

Last Updated: December 5, 2025

The Harrisburg Reservoir Dam in Illinois, also known as Harrisburg Reservoir, was completed in 1920 and serves as a crucial water resource for the local community.


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Summary

Owned by the local government, this earth dam stands at a height of 25 feet and has a length of 8400 feet. The dam has a storage capacity of 887 acre-feet, with a normal storage level of 798 acre-feet, covering a surface area of 73 acres.

Located in Saline County, the dam regulates the Middle Fork Saline-Offstream, providing water for various purposes. Despite being designated as having a low hazard potential, a high risk assessment rating of 2 indicates the importance of proper management and maintenance. The dam is under the jurisdiction of the Illinois Department of Natural Resources, which oversees permitting, inspection, and enforcement to ensure the safety and integrity of the structure.

Water resource and climate enthusiasts will find the Harrisburg Reservoir Dam an intriguing study in sustainable water management and infrastructure. With its historical significance, ecological impact, and risk assessment considerations, this dam serves as a vital piece of Illinois' water infrastructure, highlighting the intersection of human engineering and natural resource conservation in the face of changing climate patterns.

Year Completed

1920

Dam Length

8400

Dam Height

25

River Or Stream

MIDDLE FORK SALINE-OFFSTREAM

Primary Dam Type

Earth

Surface Area

73

Drainage Area

87.6

Nid Storage

887

Outlet Gates

None

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

25
       
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.