Mccall
Mccall is an earth dam located in Boulder County, Colorado, built in 1909. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Mccall
The primary purpose of Mccall is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Longmont (huson, Ken) (local government). It impounds the St. Vrain Creek-os near Longmont.
The dam stands 14 feet tall and stretches 1,900 feet across, creates a reservoir covering 51 acres, and has a maximum storage capacity of 722 acre-feet. Completed in 1909, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. 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 07/22/2022.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Colorado dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Colorado |
| County | Boulder |
| Nearest City | Longmont |
| River/Stream | St. Vrain Creek-os |
| Coordinates | 40.20208, -105.20339 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 14 ft |
| Dam Height | 14 ft |
| Dam Length | 1,900 ft |
| Year Completed | 1909 (117 years old) |
Storage & Hydraulics
| NID Storage | 722 acre-ft |
| Max Storage | 722 acre-ft |
| Normal Storage | 510 acre-ft |
| Surface Area | 51 acres |
| Max Discharge | 3,614 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | CITY OF LONGMONT (HUSON, KEN) |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/22/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CO01775 |
| Federal ID | CO01775 |
| More Info | State Dam Safety Program |