Located in Cass, Minnesota, Willow River, also known as Big Rice Lake, is a state-owned dam with a primary purpose of irrigation. Built in 1962, this gravity dam stands at 8 feet high and spans 45 feet in length. With a normal storage capacity of 5,409 acre-feet and a maximum storage of 13,465 acre-feet, the dam serves a critical role in regulating the flow of the Willow River.

Managed by the Minnesota Department of Natural Resources, Willow River is subject to state regulation, inspection, and enforcement to ensure its structural integrity and operational efficiency. Despite being classified as having a low hazard potential, the dam has a very high risk assessment rating, emphasizing the importance of ongoing risk management measures. The condition assessment in 2018 deemed the dam to be in satisfactory condition, highlighting the diligent efforts to maintain its safety and functionality for the surrounding community.

With a drainage area of 96 square miles and a maximum discharge capacity of 1,700 cubic feet per second, Willow River plays a vital role in water resource management in the region. The controlled spillway design and the presence of emergency action plans further demonstrate the commitment to safeguarding the dam and the downstream areas in the event of a potential emergency. For water resource and climate enthusiasts, Willow River serves as a fascinating example of the intersection of infrastructure, environmental stewardship, and risk management in the face of changing climatic conditions.