Williston Mill Dam (md 617 Old Harmony Road)
Williston Mill Dam (md 617 Old Harmony Road) is an earth dam located in Caroline County, Maryland, built in 1936. It carries a Low hazard potential classification and has a satisfactory condition assessment.
About Williston Mill Dam (md 617 Old Harmony Road)
The primary purpose of Williston Mill Dam (md 617 Old Harmony Road) is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Girl Scouts Of The Chesapeake Bay (private). It impounds the Mill Creek near Williston.
The dam stands 18 feet tall and stretches 630 feet across, creates a reservoir covering 51 acres, has a maximum storage capacity of 508 acre-feet, and collects water from a drainage area of 7 square miles. Completed in 1936, the structure is well-established, with more than 75 years of service.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 10/09/2024.
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Location
| State | Maryland |
| County | Caroline |
| Nearest City | Williston |
| River/Stream | Mill Creek |
| Coordinates | 38.82830, -75.84660 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 18 ft |
| Dam Height | 18 ft |
| Dam Length | 630 ft |
| Year Completed | 1936 (90 years old) |
Storage & Hydraulics
| NID Storage | 508 acre-ft |
| Max Storage | 508 acre-ft |
| Normal Storage | 180 acre-ft |
| Surface Area | 51 acres |
| Drainage Area | 7 sq mi |
| Max Discharge | 1,660 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Girl Scouts of the Chesapeake Bay |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/09/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | MD00113 |
| Federal ID | MD00113 |
| More Info | State Dam Safety Program |