Altamont Reservoir Dam Reservoir Report
Last Updated: December 5, 2025
Altamont Reservoir Dam, located in Effingham, Illinois, is a vital structure owned by the local government for water supply purposes.
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Summary
Constructed in 1972 by Russell and Axon Engineers, this earth dam stands at a height of 42 feet and stretches 506 feet in length. With a storage capacity of 1255 acre-feet and a normal storage of 950 acre-feet, the reservoir serves as a key source of water for the surrounding area.
Situated on the TRIB BIG CREEK, Altamont Reservoir Dam is regulated by the Illinois Department of Natural Resources, ensuring its compliance with state safety standards. The dam, with a spillway width of 22 feet and uncontrolled spillway type, poses a significant hazard potential but has a moderate risk assessment rating. Despite limited information on its condition assessment, the dam undergoes inspections every three years, with the last one conducted in August 2018.
For water resource and climate enthusiasts, Altamont Reservoir Dam presents an intriguing case study of a local government-owned structure designed to meet water supply needs. As a significant component of the region's infrastructure, the dam's construction and operational details provide valuable insights into the management of water resources in Illinois. Its risk assessment and hazard potential also highlight the importance of regular inspections and safety measures to ensure the continued functionality and safety of such critical infrastructure.
Year Completed |
1972 |
Dam Length |
506 |
Dam Height |
42 |
River Or Stream |
TRIB BIG CREEK |
Primary Dam Type |
Earth |
Surface Area |
62 |
Drainage Area |
1.1 |
Nid Storage |
1255 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
42 |
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.
Altamont Reservoir Dam