Allen Lake Dam Reservoir Report

Last Updated: December 26, 2025

Allen Lake Dam, located in Crawford, Illinois, is a privately owned structure with a primary purpose of recreation.


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Summary

Built in 1966 by the USDA NRCS, this earth dam stands at a height of 21 feet and has a length of 1050 feet. It holds a storage capacity of 154 acre-feet, with a normal storage level of 98 acre-feet, making it a significant water resource for the area. The dam is regulated by the Illinois Department of Natural Resources and is inspected for safety and enforcement regularly.

With its location on the TRIB SUGAR CREEK river, Allen Lake Dam provides not only recreational opportunities but also serves as a critical flood control measure in the region. The dam's spillway, classified as uncontrolled with a width of 366 feet, helps manage water levels during times of high discharge. Despite its high hazard potential, the dam is considered to have a moderate risk level, indicating a need for ongoing monitoring and risk management measures.

Although the current condition assessment of Allen Lake Dam is not available, its history and purpose highlight its importance as a water resource structure in Crawford County. With its design by the USDA NRCS and oversight by the Illinois Department of Natural Resources, the dam continues to play a vital role in water management and recreation in the area.

Year Completed

1966

Dam Length

1050

Dam Height

21

River Or Stream

TRIB SUGAR CREEK

Primary Dam Type

Earth

Nid Storage

154

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

21
       
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.