Nielsen Dam B, located in Bothell, Washington, is a privately owned structure regulated by the Washington Department of Ecology. Built in 1973, this earth dam primarily serves recreational purposes along Tr-North Creek. With a hydraulic height of 10 feet and a structural height of 9 feet, the dam has a storage capacity of 11 acre-feet and a drainage area of 0.08 square miles.

Despite its recreational focus, Nielsen Dam B has a high hazard potential and is currently rated as being in poor condition. The last inspection in August 2017 revealed the need for improvements, with a scheduled inspection frequency of every 5 years. The dam's emergency action plan status, risk assessment, and inundation maps are currently not updated or in compliance with guidelines.

The dam's location within Snohomish County, Washington, adds to its significance for water resource and climate enthusiasts. With the potential for environmental impact and the importance of maintaining its structural integrity, Nielsen Dam B stands as a reminder of the ongoing challenges and responsibilities associated with managing water resources in the region.