[en] This engineering evaluation/cost analysis (EE/CA) report has been prepared to support the proposed removal action for managing contaminated surface waters impounded at the chemical plant area of the Weldon Spring site, located near Weldon Spring, Missouri. The US Department of Energy is responsible for cleanup activities at the site under its Surplus Facilities Management Program (SFMP). The major goals of SFMP are to eliminate potential hazards to human health and the environment that are associated with contamination at SFMP sites and to make surplus real property available for other uses, to the extent possible. The objectives of this EE/CA report are to identify the cleanup as a removal action, document the selection of a response that will mitigate the potential release of radioactive or chemical contaminants from the impounded waters into the nearby environment, and address environmental impacts associated with the proposed action. 41 refs., 8 figs., 8 tabs