Moonan Marsh, located in Waseca, Minnesota, is a gravity dam built in 1967 by the USDA NRCS with a primary purpose of "Other." It stands at a height of 13 feet and has a normal storage capacity of 100 acre-feet. The dam is situated on Crane Creek in Clinton Falls and covers a drainage area of 33 square miles.

Managed by the Minnesota Department of Natural Resources, Moonan Marsh is regulated, inspected, and permitted by the state, ensuring its safety and compliance with environmental standards. With a low hazard potential and satisfactory condition assessment, the dam poses minimal risk to the surrounding area. Despite its uncontrolled spillway and outlet gates, the structure has been deemed safe and is monitored regularly to maintain its integrity.

Moonan Marsh serves as a vital resource for water conservation and climate management in the region. Its modest size and controlled discharge contribute to moderate risk management measures, allowing for the sustainable utilization of water resources in the area. As a testament to responsible stewardship, Moonan Marsh stands as a symbol of the importance of maintaining and regulating water infrastructure for the benefit of both the environment and local communities.