Lost Wilderness Lake Southern Dam is an earth dam located in Hampden County, Massachusetts, built in 1975. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 23 ft23 ft tall and 390 ft long. 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 Lost Wilderness Lake Southern Dam
The primary purpose of Lost Wilderness Lake Southern Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Ma Department of Conservation & Recreation (state). It impounds the Twining Brook to West Branch of Farmington River near Tolland.
The dam stands 23 feet tall and stretches 390 feet across, creates a reservoir covering 134 acres, has a maximum storage capacity of 2,000 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1975, the structure is well into its service life at over 50 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 04/28/2020.
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Location
| State | Massachusetts |
| County | Hampden |
| Nearest City | Tolland |
| River/Stream | Twining Brook to West Branch of Farmington River |
| Coordinates | 42.09622, -73.05549 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 23 ft |
| Dam Length | 390 ft |
| Year Completed | 1975 (51 years old) |
Storage & Hydraulics
| NID Storage | 2,000 acre-ft |
| Max Storage | 2,000 acre-ft |
| Normal Storage | 1,200 acre-ft |
| Surface Area | 134 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 159 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Ma Department of Conservation & Recreation |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/28/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00321 |
| Federal ID | MA01059S001 |
| More Info | State Dam Safety Program |