Araujo Reservoir No. 1, located in Calistoga, California, is a privately owned earth dam built in 1950 primarily for flood risk reduction. Standing at a height of 39 feet with a hydraulic height of 35.6 feet, the reservoir has a storage capacity of 21.9 acre-feet and covers a surface area of 2.3 acres. Despite being classified as having a high hazard potential, the dam is currently assessed to be in fair condition as of September 2017.

Managed by the California Department of Water Resources (DWR) under the Safety of Dams program, Araujo Reservoir No. 1 is subject to state regulations, permitting, inspection, and enforcement. The dam is situated on an unnamed river or stream, within the jurisdiction of Napa County, California. Its purpose extends beyond flood risk reduction to include irrigation and water supply, highlighting its importance in supporting local agricultural and water resource needs.

As a key infrastructure for flood risk management in the region, Araujo Reservoir No. 1 plays a vital role in safeguarding nearby communities from potential flooding events. With its strategic location and design, the reservoir serves as a critical component of the water resource system in the area, contributing to the overall resilience and sustainability of the surrounding environment.