A and C, also known as Avanzino, is a privately owned dam located in Avanzino Ranch, California. Constructed in 1923, this earth dam stands at a height of 13 feet with a hydraulic height of 7.1 feet and a length of 1200 feet. Its primary purpose is for water supply, specifically for irrigation and water supply. The dam has a storage capacity of 800 acre-feet and covers a surface area of 210 acres, serving the surrounding area with water from the Sfk Willow Creek.

Despite being classified with a low hazard potential, A and C has undergone regular state inspections and enforcement to ensure its safety and functionality. The dam is regulated by the California Department of Water Resources under the Safety of Dams program, with permits, inspections, and enforcement mechanisms in place. Its condition was assessed as satisfactory as of September 2017, with the last inspection conducted in June 2020. This structure plays a crucial role in water resource management in the region, highlighting the importance of maintaining and monitoring such infrastructure in the face of changing climate conditions.