Mann is a privately-owned dam located in Jefferson County, Colorado, near the city of Littleton. Completed in 1877, Mann serves multiple purposes including fire protection, stock and small fish pond, irrigation, and recreation. The dam is primarily an Earth type structure with a height of 15 feet and a length of 400 feet, holding a maximum storage capacity of 98 acre-feet and a normal storage capacity of 21 acre-feet. It is situated on the Dochan Gulch river, within the Omaha District of the US Army Corps of Engineers.

Despite being classified as having low hazard potential and fair condition as of its last inspection in 2007, Mann poses a high risk due to its location and the potential impact of a failure on the surrounding area. The dam does not have a spillway and is not associated with any locks or outlet gates. While it meets state permitting and inspection requirements, the dam's Emergency Action Plan (EAP) status and risk assessment measures are unclear. For water resource and climate enthusiasts, Mann represents a historic structure with the potential for significant risk management challenges in the future.