Enl. No. 4 is an earth dam located in Sweetwater County, Wyoming, built in 1973. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 37 ft37 ft tall and 4,050 ft long, taller than 83% 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 Enl. No. 4
The primary purpose of Enl. No. 4 is debris control. The dam is designed to catch sediment, rocks, and debris carried by flowing water — particularly important in areas prone to mudslides or heavy erosion. The dam is owned by Tata Chemicals North America (private). It impounds the Allied Draw near Bryan (see Remarks).
The dam stands 37 feet tall and stretches 4,050 feet across, creates a reservoir covering 291 acres, and has a maximum storage capacity of 5,184 acre-feet. Completed in 1973, 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. Its condition is rated fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 04/16/2024.
At 37 feet, this dam is taller than 83% of dams nationwide.
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Location
| State | Wyoming |
| County | Sweetwater |
| Nearest City | Bryan (see Remarks) |
| River/Stream | Allied Draw |
| Coordinates | 41.57500, -109.72500 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 37 ft |
| Dam Height | 37 ft |
| Dam Length | 4,050 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 5,184 acre-ft |
| Max Storage | 5,184 acre-ft |
| Normal Storage | 4,377 acre-ft |
| Surface Area | 291 acres |
| Max Discharge | 187 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Debris Control |
| Owner | Tata Chemicals North America |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 04/16/2024 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | WY01376 |
| Federal ID | WY01376 |
| More Info | State Dam Safety Program |