Mcnab is a privately owned dam located in Mendocino, California, specifically in the city of Hopland. Completed in 1947, this Earth-type dam stands at a height of 40 feet and serves multiple purposes including flood risk reduction, irrigation, and water supply. Its primary purpose, however, is flood risk reduction, providing a critical infrastructure for managing water resources in the region.

With a storage capacity of 96 acre-feet and a drainage area of 2.9 square miles, Mcnab plays a significant role in the management of water resources in the area. The dam is regulated by the California Department of Water Resources, Safety of Dams, ensuring that it meets necessary inspection and enforcement standards. Despite being classified as having a significant hazard potential, Mcnab is assessed to be in satisfactory condition as of its last assessment in September 2017.

Named after the nearby Mc Nab Creek, this dam is part of the broader water management infrastructure in the region and highlights the importance of maintaining and regulating such structures to mitigate flood risks and ensure water supply for various uses. For water resource and climate enthusiasts, Mcnab serves as a focal point for understanding the intersection of infrastructure, policy, and environmental conservation in managing water resources.