Reynolds, also known as St Marys Lake and Stewart, is a private irrigation dam located in Idaho Springs, Colorado. This concrete dam was completed in 1910 and stands at a height of 14 feet, with a storage capacity of 64 acre-feet. It serves the primary purpose of irrigation and has a drainage area of 0 square miles, with a maximum discharge of 38 cubic feet per second.

Managed by the Colorado Department of Water Resources, Reynolds dam is state-regulated and undergoes regular inspections, with its condition assessed as satisfactory as of September 2017. Despite its low hazard potential, the dam is categorized as having a high risk level, emphasizing the importance of effective risk management measures. With a historical significance dating back over a century, Reynolds dam remains a critical piece of infrastructure for water resource management in the region.

Located in Clear Creek County, Reynolds dam plays a vital role in water distribution and flood control along the Fall River. With its strategic location and reliable operation, the dam contributes to the overall sustainability of water resources in the area. As climate change continues to impact water availability and quality, the management and maintenance of structures like Reynolds are essential for ensuring resilience in the face of evolving environmental challenges.