Robert Coyier is a privately owned earth dam located in Mifflin, Wisconsin, along the TR Pecatonica River. Completed in 1974, this dam serves primarily for fire protection and as a stock or small fish pond. With a height of 24 feet and a hydraulic height of 15 feet, it has a storage capacity of 107 acre-feet and a drainage area of 0.2 square miles. The dam has a low hazard potential and is currently in fair condition as of the last assessment in May 2020.

Despite being privately owned, Robert Coyier is regulated by the Wisconsin Department of Natural Resources, which oversees its permitting, inspection, and enforcement. The dam has a moderate risk assessment rating of 3, indicating a level of risk that requires attention but is not immediately threatening. The dam's spillway is uncontrolled, and it has a maximum discharge capacity of 40 cubic feet per second. The last inspection of the dam was conducted in August 2010, with an inspection frequency of every 10 years.

For water resource and climate enthusiasts, Robert Coyier presents an interesting case study of a privately owned dam in rural Wisconsin. Its location along the TR Pecatonica River and its primary purposes of fire protection and stock or small fish pond highlight the diverse roles that dams play in water management. With its fair condition and moderate risk assessment, it serves as a reminder of the importance of regular inspections and maintenance to ensure the safety and reliability of such structures in the face of changing climate conditions.