Sediment Pond 4a, located in Pleasanton, Kansas, is a privately owned rockfill dam designed by Alan Bowles, P.E. The dam stands at a height of 9.1 feet and has a storage capacity of 334.9 acre-feet, serving primarily for flood risk reduction in the area. With a low hazard potential and a condition assessment that is currently not rated, Sediment Pond 4a plays a crucial role in managing water resources and protecting against potential flooding events in Linn County.

Managed by the Kansas Department of Agriculture, Sediment Pond 4a has a normal storage capacity of 149.3 acre-feet and covers a surface area of 16.9 acres. The dam's drainage area is 0.71 square miles, with a maximum discharge capacity of 341 cubic feet per second. Despite the lack of a spillway type specified, the structure meets state regulatory requirements for inspection, permitting, and enforcement, ensuring its operational safety and compliance with water resource management standards.

With its strategic location and design features, Sediment Pond 4a contributes significantly to flood risk reduction efforts in the region, providing a vital buffer against potential inundation events. As a key component of the state's water infrastructure, this rockfill dam exemplifies the importance of sustainable water resource management and climate resilience in safeguarding communities and ecosystems against the impacts of extreme weather events and ensuring the long-term integrity of water supply systems in Kansas.