Olson, located in Napa, California, is a privately owned dam on Ledgewood Creek with a primary purpose of water supply for irrigation and other uses. Completed in 1955, this earth dam stands at a height of 45 feet and spans 646 feet in length, with a storage capacity of 200 acre-feet. The dam has a high hazard potential but is currently in satisfactory condition, last assessed in September 2017.

Regulated by the California Department of Water Resources for safety, Olson undergoes regular inspections and enforcement to ensure its integrity and compliance with state regulations. The dam's location in Palo Cedro, near San Francisco District, makes it a critical water resource for the region. While the dam has not been modified in recent years and lacks certain features like spillways and locks, its importance for water supply in the area cannot be understated.

Water resource and climate enthusiasts can appreciate the significance of Olson as a vital infrastructure for water management in California. With its historical significance, high hazard potential, and regulatory oversight, Olson serves as a key player in the state's water supply system. As climate change continues to impact water resources, understanding and monitoring dams like Olson is crucial for ensuring sustainable water management practices in the face of environmental challenges.