Lost Lake #1, also known as Lower Lost Lake, is a private water resource located in Hinsdale, Colorado, specifically in the city of South Fork. Built in 1907 for irrigation purposes, this earth dam stands at a height of 22 feet and stretches 182 feet in length. With a storage capacity of 1181 acre-feet, this reservoir serves multiple functions, including fish and wildlife pond, irrigation, and recreation.

Situated on Lost Lake Creek, this dam is regulated by the Colorado Department of Water Resources and is inspected regularly to ensure its structural integrity. With a low hazard potential and satisfactory condition assessment, Lost Lake #1 poses minimal risk to the surrounding area. The spillway, outlet gates, and overall design of the dam contribute to its efficient operation, maintaining a moderate risk assessment rating.

Water resource and climate enthusiasts will appreciate the historical significance and multi-purpose functionality of Lost Lake #1. From its construction over a century ago to its current role in sustaining irrigation and recreational activities, this dam on Lost Lake Creek embodies the balance between human utilization of water resources and environmental conservation. With careful regulation and maintenance, Lost Lake #1 continues to serve as a vital component of Colorado's water infrastructure.