Green Lake No. 1 is a rockfill dam located in Boulder, Colorado, along the North Boulder Creek-TR. Completed in 1940, this dam primarily serves the purpose of water supply, with a storage capacity of 60 acre-feet and a normal storage of 40 acre-feet. The dam stands at a height of 24 feet and has a length of 270 feet, providing important water resources for the local community.

Despite being classified as having a low hazard potential, Green Lake No. 1 has a moderate risk assessment rating of 3. The last inspection of the dam took place in July 1985, with the condition currently marked as "Not Rated". While the dam meets state regulations for permitting, inspection, and enforcement, there is no Emergency Action Plan (EAP) in place, and the risk management measures are not specified.

Located within the Sacramento District of the US Army Corps of Engineers, Green Lake No. 1 is a vital water infrastructure managed by the local government. With its strategic location and historical significance, this dam stands as a testament to the importance of water resource management and climate resilience in the region.