Blandinsville City Reservoir Dam Reservoir Report

Last Updated: January 12, 2026

Located in Blandinsville, Illinois, the Blandinsville City Reservoir Dam stands as a critical infrastructure for water supply in the region.


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Summary

Built in 1940, this earth dam, designed by J. W. Grenshaw, stands at a height of 20 feet and stretches over 2680 feet in length. With a normal storage capacity of 75 acre-feet and a maximum storage capacity of 126 acre-feet, the dam serves as a vital source of water for the surrounding area.

Managed by the local government and regulated by the Illinois Department of Natural Resources, the Blandinsville City Reservoir Dam is subject to regular inspections to ensure its safety and functionality. Despite its high hazard potential, with a risk assessment rating of 2, the dam continues to play a crucial role in the water management system of McDonough County. While the condition assessment is currently not available, efforts to maintain and monitor the dam are ongoing to mitigate any potential risks and ensure the safety of the surrounding community.

With no spillway and no outlet gates, the dam's design and construction reflect a specific focus on water supply purposes. As a key component of the Little Creek-Offstream system, the Blandinsville City Reservoir Dam exemplifies the intersection of water resource management and climate resilience in the region. As enthusiasts of water resources and climate initiatives, the Blandinsville City Reservoir Dam stands as a notable structure worth exploring for its historical significance and ongoing role in sustaining water security for the local area.

Year Completed

1940

Dam Length

2680

Dam Height

20

River Or Stream

LITTLE CREEK-OFFSTREAM

Primary Dam Type

Earth

Surface Area

8

Nid Storage

126

Outlet Gates

None

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

20
       
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.