Hartley Lake, located in Itasca, Minnesota, is a state-regulated reservoir with a low hazard potential but a very high risk assessment. Constructed in 1938, this gravity dam stands at a height of 7.5 feet and has a structural height of 12 feet, providing a storage capacity of 1925 acre-feet. The reservoir covers an area of 318 acres and serves as a water resource for the surrounding area.

Managed by the Minnesota Department of Natural Resources, Hartley Lake has a controlled spillway and a fair condition assessment as of January 2018. Despite its low hazard potential, the reservoir is considered to have a very high risk due to potential factors that could impact its operation and safety. The dam's emergency action plan status and risk management measures are currently not available, highlighting the need for ongoing monitoring and assessment of this vital water resource in the Prairie River watershed.

The location of Hartley Lake in La Prairie, Minnesota, makes it an important feature in the local landscape, providing recreational opportunities and supporting ecological diversity. With its historical significance dating back to the Works Progress Administration era, this reservoir serves as a reminder of the importance of responsible water resource management in the face of changing climate patterns and environmental challenges.