Techny Reservoir Dam Reservoir Report

Last Updated: December 5, 2025

Techny Reservoir Dam, also known as Techney Reservoir, is a crucial structure located in Glenview, Illinois, along the West Fork North Branch Chicago River.


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Summary

Built in 1979 by Alfred Benesch & Co., this earth dam stands at a height of 11 feet and stretches 544 feet in length. Its primary purpose is flood risk reduction, with a storage capacity of 350 acre-feet and a spillway width of 89 feet.

Managed by the local government and regulated by the Illinois Department of Natural Resources, Techny Reservoir Dam plays a vital role in protecting the surrounding area from potential flooding. The dam's hazard potential is categorized as significant, with a moderate risk assessment score of 3. While its condition assessment is currently unavailable, regular inspections are conducted, with the last one taking place in October 2015.

Despite its age, Techny Reservoir Dam continues to serve as a critical infrastructure for flood control in Cook County. As water resource and climate enthusiasts, understanding the engineering and operational aspects of this dam provides valuable insights into sustainable water management practices and the importance of maintaining and monitoring our infrastructure to mitigate potential risks associated with extreme weather events.

Year Completed

1979

Dam Length

544

Dam Height

11

River Or Stream

WEST FORK NORTH BRANCH CHICAGO RIVER

Primary Dam Type

Earth

Nid Storage

350

Outlet Gates

None

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

11
       
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.