Dresden Island Lock and Dam is a concrete dam located in Grundy County, Illinois, built in 1933. It carries a Significant hazard potential classification.
Dam profile
NID height · 33 ft33 ft tall and 1,750 ft long, taller than 76% of U.S. dams with a recorded height. 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 Dresden Island Lock and Dam
The primary purpose of Dresden Island Lock and Dam is navigation. The dam maintains water levels sufficient for boat and barge traffic, supporting commercial or recreational navigation on the waterway. The dam is owned by USACE - Rock Island District (federal). It impounds the Illinois River near Morris.
The dam stands 33 feet tall and stretches 1,750 feet across, creates a reservoir covering 2,180 acres, has a maximum storage capacity of 12,000 acre-feet, and collects water from a drainage area of 7,278 square miles. Completed in 1933, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 04/23/2024.
At 33 feet, this dam is taller than 76% of dams nationwide.
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Location
| State | Illinois |
| County | Grundy |
| Nearest City | Morris |
| River/Stream | Illinois River |
| Coordinates | 41.39951, -88.28131 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 33 ft |
| Dam Length | 1,750 ft |
| Year Completed | 1933 (93 years old) |
Storage & Hydraulics
| NID Storage | 12,000 acre-ft |
| Max Storage | 12,000 acre-ft |
| Surface Area | 2,180 acres |
| Drainage Area | 7,278 sq mi |
| Max Discharge | 113,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - Rock Island District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 04/23/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | IL00002 |
| Federal ID | IL00002 |
| More Info | State Dam Safety Program |