Totagatic, also known as Nelson Lake, is a gravity dam located in Sawyer, Wisconsin, with a primary purpose of recreation. Completed in 1936, Totagatic stands at a height of 20 feet and has a maximum storage capacity of 38,000 acre-feet and a normal storage capacity of 21,000 acre-feet. The dam has a surface area of 2,503 acres and a drainage area of 49.8 square miles, with a controlled spillway width of 37 feet.

Managed by the Wisconsin Department of Natural Resources, Totagatic is regulated, permitted, inspected, and enforced by state authorities. The dam has a low hazard potential and has not been rated for its current condition. While it has a very high risk assessment rating due to its age and other factors, the emergency action plan for Totagatic meets guidelines and is regularly updated to ensure the safety of the surrounding area in case of a potential breach.

With its scenic location and recreational opportunities, Totagatic serves as a popular destination for water resource and climate enthusiasts. Its historical significance, combined with its natural beauty and the efforts to maintain its safety and functionality, make it a noteworthy site for those interested in the intersection of water management and environmental conservation.