Brookdale Dam is a concrete dam located in McHenry County, Illinois. It carries a Significant hazard potential classification.
Dam profile
NID height · 8 ft8 ft tall and 400 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Brookdale Dam
The primary purpose of Brookdale Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Mchenry County Conservation District (local government). It impounds the North Branch Kishwaukee River near Marengo.
The dam stands 8 feet tall and stretches 400 feet across, creates a reservoir covering 12 acres, has a storage capacity of 88 acre-feet, and collects water from a drainage area of 21 square miles.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. The most recent inspection on record was 10/18/2024.
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Location
| State | Illinois |
| County | McHenry |
| Nearest City | Marengo |
| River/Stream | North Branch Kishwaukee River |
| Coordinates | 42.35735, -88.55479 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 8 ft |
| Dam Height | 8 ft |
| Dam Length | 400 ft |
Storage & Hydraulics
| NID Storage | 88 acre-ft |
| Normal Storage | 88 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 21 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Mchenry County Conservation District |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 10/18/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL55152 |
| Federal ID | IL55152 |
| More Info | State Dam Safety Program |