Big Monitor No.1 is a privately owned irrigation dam located in Montrose, Colorado, along the Roubideau Creek. Built in 1948 by USDA NRCS, this Earth-type dam stands at 20 feet tall and spans 470 feet in length, with a storage capacity of 310 acre-feet. The primary purpose of this dam is irrigation, serving the surrounding area for fire protection, stock watering, and small fish ponds.

With a significant hazard potential, Big Monitor No.1 has a hydraulic height of 18 feet and a maximum discharge of 1262 cubic feet per second. While the condition assessment is not available, the dam is currently not regulated or inspected by any state agency. Despite its age, the dam continues to play a crucial role in water resource management in the region, highlighting the importance of maintaining and monitoring such structures for the sustainability of water supply and climate resilience.