Loch Mcwilliams Dam is an earth dam located in St. Tammany Parish, Louisiana, built in 1983. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 26 ft26 ft tall and 1,107 ft long, taller than 55% 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 Loch Mcwilliams Dam
The primary purpose of Loch Mcwilliams Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by The Highlands Homeowners Association of St. Tammany, Inc. (private). It impounds the Tr-bills Creek near Covington.
The dam stands 26 feet tall and stretches 1,107 feet across, creates a reservoir covering 59 acres, has a maximum storage capacity of 700 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1983, the structure is 43 years old.
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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 12/02/2024.
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Location
| State | Louisiana |
| County | St. Tammany |
| Nearest City | Covington |
| River/Stream | Tr-bills Creek |
| Coordinates | 30.64275, -90.09278 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 26 ft |
| Dam Height | 24 ft |
| Dam Length | 1,107 ft |
| Year Completed | 1983 (43 years old) |
Storage & Hydraulics
| NID Storage | 700 acre-ft |
| Max Storage | 700 acre-ft |
| Normal Storage | 530 acre-ft |
| Surface Area | 59 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 1,950 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | The Highlands Homeowners Association of St. Tammany, Inc. |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 12/02/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | LA00599 |
| Federal ID | LA00599 |
| More Info | State Dam Safety Program |