Lake In The Hills 3 Dam Reservoir Report
Last Updated: December 13, 2025
Lake In The Hills 3 Dam, located in McHenry, Illinois, is a concrete buttress dam completed in 1940 with a primary purpose of recreation.
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Summary
Managed by the local government, this dam on Crystal Creek has a height of 10 feet and a length of 70 feet, providing a storage capacity of 70 acre-feet. With a low hazard potential and moderate risk assessment, the dam is state-regulated and inspected regularly by the Illinois Department of Natural Resources.
Designed by Wight Consulting Engineers, Lake In The Hills 3 Dam serves as a vital recreational resource for the community, offering opportunities for boating, fishing, and other water-based activities. While the dam does not have any associated structures or outlet gates, it plays a crucial role in managing water flow and ensuring the safety of downstream areas. Despite its age, the dam remains in good condition, with a five-year inspection frequency and a commitment to meeting state regulatory guidelines.
With a controlled spillway type and a maximum discharge capacity of 1550 cubic feet per second, Lake In The Hills 3 Dam is an important piece of infrastructure that contributes to the overall water management system in the region. As climate change continues to impact water resources, the proper maintenance and upkeep of dams like this one are essential to safeguarding both the environment and local communities. By staying proactive in risk management and emergency preparedness, the stakeholders involved can ensure the long-term safety and functionality of this critical water resource.
Year Completed |
1940 |
Dam Length |
70 |
Dam Height |
10 |
River Or Stream |
CRYSTAL CREEK |
Primary Dam Type |
Concrete |
Surface Area |
10 |
Drainage Area |
11.8 |
Nid Storage |
70 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
10 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Fox River At Algonquin
|
725cfs |
Fox River At Algonquin (Tailwater)
|
644cfs |
Tyler Creek At Elgin
|
8cfs |
Boone Creek Near Mc Henry
|
10cfs |
Poplar Creek At Elgin
|
7cfs |
Fox River At South Elgin
|
759cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Lake In The Hills 3 Dam
Hilltop Drive 145, Lake in the Hills