Carl, also known as Grandpa's Lake, is a privately owned Earth dam located in Lincoln, Wisconsin. Completed in 1957, this recreational structure stands at 11 feet tall and spans 2000 feet in length, with a maximum storage capacity of 160 acre-feet. Despite its low hazard potential, Carl is currently rated as being in poor condition, with a recent assessment conducted in November 2020.

Managed by the Wisconsin Department of Natural Resources, Carl is subject to state regulations, inspections, and enforcement measures to ensure its safety and functionality. With a drainage area of 2 square miles and a maximum discharge capacity of 250 cubic feet per second, this dam plays a crucial role in maintaining the water levels of the surrounding area. Although its condition is deemed poor, efforts are likely underway to address any necessary repairs or maintenance to mitigate potential risks and improve its overall performance.

For water resource and climate enthusiasts, Carl serves as a valuable case study in the management of recreational dams in Wisconsin. Its location, design, and historical significance offer insights into the challenges and opportunities associated with maintaining aging infrastructure in a changing climate. As efforts continue to assess and address its condition, Carl remains a focal point for ongoing discussions on water resource management and dam safety in the region.