New Harrisburg Reservoir Dam Reservoir Report
Last Updated: December 29, 2025
The New Harrisburg Reservoir Dam, also known as the Harrisburg Reservoir, is a significant earth dam located in Illinois, specifically in Saline County near the city of Galatia-Offstream.
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Summary
Built in 1955, this dam serves multiple purposes, including water supply and flood control along the tributary of the Middle Fork Saline River. With a height of 38 feet and a length of 1000 feet, the dam has a storage capacity of 6233 acre-feet, providing essential water resources to the surrounding area.
Managed by the local government and regulated by the Illinois Department of Natural Resources, the New Harrisburg Reservoir Dam is classified as having a significant hazard potential with a moderate risk assessment. The dam features uncontrolled spillways and outlet gates, with a maximum discharge capacity of 8804 cubic feet per second. While the condition assessment is not available, the dam undergoes inspections every three years to ensure its structural integrity and safety. Overall, this dam plays a crucial role in water management and climate resilience efforts in the region, demonstrating the importance of sustainable water resource infrastructure for environmental protection and community well-being.
For water resource and climate enthusiasts, the New Harrisburg Reservoir Dam is a fascinating example of earth dam engineering and management practices in Illinois. Its history, design features, and operational characteristics highlight the complex interplay between water supply, flood control, and environmental stewardship. As climate change impacts continue to pose challenges to water infrastructure, understanding the role of dams like New Harrisburg in adapting to changing conditions becomes increasingly important for ensuring the resilience of water resources in the face of a changing climate.
Dam Height |
38 |
Drainage Area |
6.3 |
Year Completed |
1955 |
Nid Storage |
6233 |
Foundations |
Unlisted/Unknown |
Surface Area |
218 |
Outlet Gates |
Uncontrolled |
River Or Stream |
TRIB MIDDLE FORK SALINE RIVER |
Dam Length |
1000 |
Hazard Potential |
Significant |
Primary Dam Type |
Earth |
Nid Height |
38 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
New Harrisburg Reservoir Dam