Triangle Lake Dam Reservoir Report

Last Updated: December 19, 2025

Triangle Lake Dam, also known as Quincy Bay, is a state-owned structure located in Adams County, Illinois, along Frazier Creek.


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Summary

Constructed in 2000 by KLINGNER & ASSOCIATES, this earth dam serves as a Fish and Wildlife Pond with a height of 18 feet and a length of 8500 feet. The dam has a storage capacity of 2757 acre-feet and a surface area of 250 acres, providing essential habitat for local wildlife.

Managed by the Illinois Department of Natural Resources (IDNR), Triangle Lake Dam is regulated, permitted, inspected, and enforced by the state. With a controlled spillway and low hazard potential, the dam poses minimal risk to surrounding areas. Despite limited information on its current condition, the dam has been assessed as having a very high risk rating, emphasizing the importance of regular monitoring and maintenance to ensure its continued safety and effectiveness in water resource management.

Triangle Lake Dam plays a crucial role in supporting the ecological balance and water resources in the region, serving as a valuable asset for both wildlife and the community. With its strategic location and design, the dam exemplifies the intersection of water resource management and climate resilience, highlighting the ongoing efforts to safeguard the environment and promote sustainable practices in dam infrastructure.

Year Completed

2000

Dam Length

8500

Dam Height

18

River Or Stream

FRAZIER CREEK

Primary Dam Type

Earth

Surface Area

250

Drainage Area

17

Nid Storage

2757

Outlet Gates

Other Controlled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

18
       
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.