A General Investigation (GI) study often begins with a request for assistance from a community or a local or state government entity with a water resource need (e.g., navigation, flood protection or ecosystem restoration) beyond its capability. Before initiating a study, the Corps generally requires two types of congressional authority - authorization and appropriations.
If the Corps has previously conducted a study in the geographic area of concern, a new study can be authorized through a House Transportation and Infrastructure Committee or Senate Environment and Public Works Committee resolution.
If the Corps has not previously conducted a study in the geographic area of concern, a new study would need to be authorized through legislation, typically a Water Resources Development Act (WRDA). Once authorized, appropriations for GI studies are appropriated as individual line items in the annual Energy and Water Development Appropriations Act, and historically Congress has modified funding amounts through congressional adds.
There are generally two phases that a project passes through using GI funding before being authorized for construction: feasibility and preconstruction engineering and design. Both of these phases are conducted under a single congressional study authority.