Little H O, also known as Upper Reservoir or Hankinson No 2, is a private dam located in Hot Sulphur Springs, Colorado. Completed in 1951, this earth dam stands at a height of 26 feet with a hydraulic height of 32 feet, serving primarily for irrigation purposes. The dam has a maximum storage capacity of 73 acre-feet and covers a surface area of 7 acres, with a normal storage capacity of 35 acre-feet.

Despite its age, Little H O is rated as having a low hazard potential and fair condition assessment, last inspected in November 2013. The dam features an uncontrolled spillway with a width of 10 feet, allowing for a maximum discharge of 200 cubic feet per second. While it is state-regulated with permits and inspections in place, the risk assessment for the dam is moderate (3), indicating a need for ongoing monitoring and potential risk management measures in the future.

Located in Grand County, Colorado, Little H O's design includes stone core types and an unlisted/unknown foundation. With its association with the Walden Hollow-TR river or stream, this dam plays a crucial role in supporting the local irrigation needs and highlights the importance of maintaining and monitoring water resources in the face of changing climate conditions.