This dataset was acquired from the Louisiana state lands office in paper format. The data were scanned and georectified in ERDAS Imagine. The data were assembled into map format in the 1940s based on original township and range descriptions. The map shows the earliest detailed configuration of the Atchafalaya basin, and particularly Grand Lake, before the onset of levee construction in the 1930s. The Atchafalaya Basin is a resource that must be managed on a system-wide basis to ensure this invaluable national resource is protected and restored. It is recognized that better tools must be developed for managing the Basin and that data evaluation is necessary to ensure sound decision-making. The natural resource inventory and assessment system (NRIAS) that was approved and funded in the FY 2010 Louisiana Department of Natural Resources Atchafalaya Basin Program Annual Plan and served as the primary tool for decision making in the Basin. The system provided a means for scientists to access relevant project data for the Basin and to request and fund data acquisition, monitoring, and data analysis to be used in project planning. This will be critical in providing information necessary for the development and approval of specific projects to be included for construction in future Annual Plans, projects that meet the needs of Louisiana citizens and protect our our natural resources. This and related datasets were created to demonstrate the patterns of inundation, turbid water and floating aquatic vegetation in the Atchafalaya Basin Floodway System at various river levels of the Atchafalaya River.Allen, Y.C., Constant, G.C., and Couvillion, B.R., 2008, Preliminary classification of water areas within the Atchafalaya Basin Floodway System by using Landsat imagery: U.S. Geological Survey Open-File Report 2008 1320, 14 p. https://pubs.er.usgs.gov/usgspubs/ofr/ofr20081320