Soap Creek Watershed Site 4-90a, located in Selma, Iowa, is a locally owned earth dam designed by the USDA NRCS to reduce flood risk in the area. Completed in 2011, this dam stands at a height of 36 feet and spans 420 feet, with a storage capacity of 145 acre-feet. The dam is situated on the Tr to Soap Creek and is regulated by the Iowa DNR, with state permitting, inspection, and enforcement in place to ensure its proper functioning.

With a low hazard potential and a condition assessment of "Not Rated," Soap Creek Watershed Site 4-90a serves as an important piece of infrastructure for flood risk reduction in the region. The dam has a spillway width of 22 feet and a maximum discharge capacity of 336 cubic feet per second. Its primary purpose is flood risk reduction, with a normal storage capacity of 28 acre-feet and a drainage area of 0.49 square miles. The dam is constructed of earth and stone materials and is supported by a soil foundation, making it a sturdy and reliable structure for managing water resources in the area.

Overall, Soap Creek Watershed Site 4-90a plays a crucial role in protecting the surrounding community from flooding events and ensuring the safe management of water resources in the region. With oversight from the Iowa DNR and support from the USDA NRCS, this dam stands as a testament to effective collaboration between local and state agencies in addressing climate-related challenges and safeguarding the environment for future generations.