Big Tujunga No. 1, also known as Big Tujunga Reservoir, is a significant structure located in Sunland, California, along the Big Tujunga Creek. Owned by the local government and regulated by the Department of Water Resources for the safety of dams, this arch-type dam was completed in 1931 with a height of 220 feet and a storage capacity of 5750 acre-feet. The primary purpose of this dam is flood risk reduction, although it also serves as a source of water supply for the region.

With a maximum discharge capacity and a hazard potential rated as high, the Big Tujunga No. 1 dam has been inspected regularly to ensure its structural integrity. The condition assessment conducted in 2017 deemed it satisfactory, and emergency action plans have been put in place to mitigate risks. Located in Los Angeles County, California, this dam is crucial for managing water resources and reducing flood risks in the area, highlighting the importance of proper maintenance and regulation in the face of changing climate conditions.