Twin Lakes Lane South Lake Dam is an earth dam located in Madison County, Illinois, built in 1966. It carries a Low hazard potential classification.
Dam profile
NID height · 31 ft31 ft tall and 174 ft long, taller than 72% 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 embankment section and the water level is illustrative.
About Twin Lakes Lane South Lake Dam
The primary purpose of Twin Lakes Lane South Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by John Jones (private). It impounds the Trib Silver Creek near Mascoutah.
The dam stands 31 feet tall and stretches 174 feet across, and has a maximum storage capacity of 148 acre-feet. Completed in 1966, the structure is well into its service life at over 50 years old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. The most recent inspection on record was 08/20/2025.
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Location
| State | Illinois |
| County | Madison |
| Nearest City | Mascoutah |
| River/Stream | Trib Silver Creek |
| Coordinates | 38.79984, -89.87457 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 31 ft |
| Dam Height | 31 ft |
| Dam Length | 174 ft |
| Year Completed | 1966 (60 years old) |
Storage & Hydraulics
| NID Storage | 148 acre-ft |
| Max Storage | 148 acre-ft |
| Normal Storage | 80 acre-ft |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | John Jones |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 08/20/2025 |
| Emergency Action Plan | No |
Identifiers
| NID ID | IL00431 |
| Federal ID | IL00431 |
| More Info | State Dam Safety Program |