Alpine Dam Reservoir Report

Last Updated: December 5, 2025

Alpine Dam, also known as Reuben Aldeen Park Lake, is a vital structure located in Rockford, Illinois, owned by the local government.


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Summary

Completed in 1942, this earth dam stands at a height of 48 feet and stretches for 600 feet, serving primarily for flood risk reduction along Keith Creek. With a storage capacity of 1770 acre-feet, it plays a crucial role in managing water levels during periods of heavy rainfall and potential flooding events in the region.

Managed by the City of Rockford, Alpine Dam is regulated by the Illinois Department of Natural Resources (IDNR) and undergoes regular inspections to ensure its structural integrity. The dam features a controlled spillway with a width of 107 feet and other controlled outlet gates. With a hazard potential rated as high and a risk assessment categorizing it as very high, Alpine Dam is a key component in mitigating flood risks and protecting the surrounding areas from potential inundation. The dam's location in Winnebago County, Illinois, underlines its importance in safeguarding the community from water-related emergencies.

As a significant infrastructure project in the Rock Island District, Alpine Dam is a critical asset for water resource and climate enthusiasts. Its role in flood risk reduction, high hazard potential, and very high risk assessment highlight the importance of proper management and maintenance to ensure the safety and well-being of the local community. With a history dating back to the early 1940s, Alpine Dam continues to serve as a vital structure in the region, showcasing the ongoing commitment to water resource management and climate resilience in the face of changing environmental conditions.

Year Completed

1942

Dam Length

600

Dam Height

48

River Or Stream

KEITH CREEK

Primary Dam Type

Earth

Drainage Area

7.1

Nid Storage

1770

Outlet Gates

Other Controlled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

48
       
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.