Box Elder #5, also known as Jameson Reservoir, is a historic earth dam located in Larimer County, Colorado. Completed in 1888, this privately-owned structure serves primarily for irrigation purposes, with secondary functions including fire protection, stock, and small fish pond usage. The dam stands at a height of 10 feet and has a length of 320 feet, with a storage capacity of 80 acre-feet.

Situated along Boxelder Creek, this reservoir has a spillway width of 20 feet and a maximum discharge capacity of 302 cubic feet per second. Despite being classified as having a low hazard potential, it is subject to state regulation, permitting, inspection, and enforcement by the Colorado Division of Water Resources. The last inspection of Box Elder #5 was conducted in August 1991, with a moderate risk assessment rating of 3.

Water resource and climate enthusiasts will appreciate the historical significance and functional diversity of Box Elder #5. As an integral component of the local irrigation system, this dam plays a crucial role in supporting agricultural activities in the region. With a focus on safety and risk management, ongoing regulatory oversight ensures the continued operation and maintenance of this essential water infrastructure in Larimer County.