Congress authorizes and appropriates funds for the U.S. Army Corps of Engineers (Corps) to conduct water resources studies and projects for navigation, flood and storm protection, ecosystem restoration, and an array of other purposes. This report explains how the congressional authorization and appropriations process overlays the Corps' project development process. Special attention is given to initiating a water resources study, the WRDA process, civil works appropriations, and emergency response activities. Authorization of Water Resources Activities. Congress generally authorizes Corps studies generally as part of a Water Resources Development Act (WRDA) or in a survey resolution passed by an authorizing committee. WRDAs, which often are considered biennially, also include authorizations to construct projects and changes to policies guiding the Corps civil works program, such as the split of project costs between the federal government and the non-federal project sponsors. Agency Appropriations. Federal funding is provided for the civil works activities of the Corps primarily through the annual Energy and Water Development Appropriations Act. These appropriations acts also may include authorizations of Corps activities; authorization provisions in appropriations provisions, however, may be subject to congressional parliamentary points of order. Due in part to competition for limited funding, many authorized activities do not receive appropriations, resulting in a backlog of authorized construction and maintenance activities. Few new studies and new construction activities have been included in the President's budget request in recent years. Natural Disaster and Emergency Response Activities and Appropriations. In addition to its role in water resources development, the civil works responsibilities of the Corps include emergency and natural disaster response; some of this work is conducted through mission assignments directed by Federal Emergency management Agency (FEMA), and other work is conducted independently through the Corps' natural disaster response authority.