Nielsen Dam B
Nielsen Dam B is an earth dam located in Snohomish County, Washington, built in 1973. It carries a High hazard potential classification and has a poor condition assessment.
About Nielsen Dam B
The primary purpose of Nielsen Dam B is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Green Acres Mobile Home Park (private). It impounds the Tr-north Creek near Bothell.
The dam stands 9 feet tall and stretches 300 feet across, creates a reservoir covering 10 acres, has a maximum storage capacity of 10 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1973, the structure is well into its service life at over 50 years 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 07/06/2022.
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 Washington 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 | Washington |
| County | Snohomish |
| Nearest City | Bothell |
| River/Stream | Tr-north Creek |
| Coordinates | 47.78152, -122.20856 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 9 ft |
| Dam Length | 300 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 10 acre-ft |
| Max Storage | 10 acre-ft |
| Normal Storage | 10 acre-ft |
| Surface Area | 10 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 27 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Green Acres Mobile Home Park |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 07/06/2022 |
| Emergency Action Plan | No |
Identifiers
| NID ID | WA01521 |
| Federal ID | WA01521 |
| More Info | State Dam Safety Program |