C. Thomsen, also known as Custer Lake, is a Federal-owned water resource located in Park, Wyoming. This earth dam, designed by Howard F. Bell in 1930, serves multiple purposes including fire protection, stock watering, small fish pond, and irrigation. The dam stands at a height of 13 feet with a hydraulic height of 10 feet, providing a storage capacity of 80 acre-feet and covering a surface area of 22 acres.

Despite being classified as having a low hazard potential, the dam is regularly inspected by the regulatory agencies in Wyoming to ensure its fair condition and continued safety. The spillway, classified as "Uncontrolled", is 8 feet wide and capable of managing water discharge. The dam is equipped with other controlled outlet gates to manage water releases as needed. C. Thomsen is an important structure for water resource management in the area, contributing to both agricultural and environmental needs.

In the event of an emergency, the dam has protocols in place to manage potential risks, with a moderate risk assessment rating. With Liz Cheney (R) representing the Congressional District in which C. Thomsen is located, the dam plays a crucial role in providing water for various uses while ensuring the safety and security of the surrounding community. For water resource and climate enthusiasts, C. Thomsen serves as a fascinating example of how infrastructure can support both human and environmental needs in a sustainable manner.