The document discusses inundation mapping of the Willamette River Basin that will be used to assess how regulated flows influence the floodplain ecologically, socially, and economically. Inundation maps and GIS data will be created for the mainstem Willamette River from Eugene to Oregon City, as well as the Middle Fork and Coast Fork Willamette Rivers and McKenzie River, using available gage data and a topographic surface model. This information will provide a tool for restoration planning, historical wetlands analysis, and other efforts. Currently, mainstem Willamette River inundation maps and data are available online, with additional maps and data to come for other areas.