This Engineering Documentation Report and Supplemental Environmental Assessment for the Lower Mud River, Milton, West Virginia Flood Risk Management Project(EDR/SEA) analyzes and documents the proposed flood risk management improvements for the City of Milton, West Virginia. An Engineering Documentation Report (EDR) is a technical implementation document that supplements the previous Decision Document and documents changes in design and cost of the authorized project. This Lower Mud EDR/SEA documents the design and cost refinements that supplement the Lower Mud River, Milt on, West Virginia, Flood Risk Management Project Final Decision Document and Environmental Assessment (DD/EA) dated September 2019. This EDR/SEA follows guidance in ER 1110-2-1150, with the National Environmental Policy Act (NEPA) of 1969, as amended, and the Council of Environmental Quality’s Regulations (CEQ) (40 CFR 1500-1508), as reflected in the USACE Engineering Regulation, ER 200-2-2.