U.S. Fish & Wildlife ServiceThese data represent the approximate delineation of land and water in the area of Grand Lake in the Atchafalaya basin in the early 1800s. These data are based on a georectified map of the original township surveys conducted between 1807 and 1838. The composite township survey map was created in 1948 and was obtained from the Louisiana State Lands Office in Baton Rouge, LA. The composite township survey map was georectified using airphots and lidar to current landforms using ERDAS Imagine. The delineation of land and water was conducted using Adobe Photoshop, and was restricted to an arbitrarily defined area that captured most of the former extent of Grand Lake. The resolution of the original delineation was 3x3m and was ressampled to 30x30m in this application for comparison to modern data sources These data represent the approximate delineation of land and water in the area of Grand Lake in the Atchafalaya basin in the early 1800s. These data are based on a georectified map of the original township surveys conducted between 1807 and 1838. The composite township survey map was created in 1948 and was obtained from the Louisiana State Lands Office in Baton Rouge, LA. The composite township survey map was georectified using airphots and lidar to current landforms using ERDAS Imagine. The delineation of land and water was conducted using Adobe Photoshop, and was restricted to an arbitrarily defined area that captured most of the former extent of Grand Lake. The resolution of the original delineation was 3x3m and was ressampled to 30x30m in this application for comparison to modern data sources. 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.ArcGIS ImageMapLayerhttps://hub.arcgis.com/datasets/8d16f9f7f3a24242914b540f9994efc8engU.S. Fish and Wildlife Service Open DataPublicGrand Lake Extent 1830 [United States]Web servicesUnited StatesLast Modified: 2025-04-14