E-21b, also known as Ksnoname 2755, is a locally owned Earth type dam located in Jefferson County, Kansas on Little Slough Creek. Completed in 1958, this dam stands at a height of 39.9 feet and serves the primary purpose of flood risk reduction. With a storage capacity of 293 acre-feet and a drainage area of 0.8 square miles, E-21b plays a crucial role in managing water resources in the region.

Managed by the Kansas Department of Agriculture, E-21b has a low hazard potential and a moderate risk assessment rating of 3. Although the dam has not been rated for its current condition, it undergoes regular inspections by the state regulatory agency to ensure its safety and effectiveness in flood control. Despite having no outlet gates, E-21b features an uncontrolled spillway with a width of 60 feet, allowing for the controlled release of excess water during heavy rainfall events.

With its strategic location and design features, E-21b serves as a key component in the flood risk reduction infrastructure of Jefferson County, Kansas. Maintaining and monitoring this dam is essential for protecting surrounding communities and managing water resources effectively in the face of climate change and extreme weather events.