Grist Mill Dam is an earth dam located in Middlesex County, Massachusetts. It carries a Low hazard potential classification and has a poor condition assessment.
Dam profile
NID height · 10 ft10 ft tall and 75 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 Grist Mill Dam
The primary purpose of Grist Mill Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Town of Hopkinton (local government). It impounds the Cold Spring Brook near Hopkinton.
The dam stands 10 feet tall and stretches 75 feet across, creates a reservoir covering 23 acres, has a maximum storage capacity of 90 acre-feet, and collects water from a drainage area of 4 square miles.
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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 07/31/2023.
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Location
| State | Massachusetts |
| County | Middlesex |
| Nearest City | Hopkinton |
| River/Stream | Cold Spring Brook |
| Coordinates | 42.21845, -71.48032 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Length | 75 ft |
Storage & Hydraulics
| NID Storage | 90 acre-ft |
| Max Storage | 90 acre-ft |
| Normal Storage | 28 acre-ft |
| Surface Area | 23 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 160 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Town of Hopkinton |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Poor |
| Last Inspection | 07/31/2023 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | MA02726 |
| Federal ID | MA02726 |
| More Info | State Dam Safety Program |