UPDATING BOUNDARIES FOR LARGE WATER BODIES OF THE USING LANDSAT 8

South Dakota State University Landsat 8 drawing. Credit: NASA Department of Geography – Bruce V. Millett

A BSTRACT M ETHODS R E S U L T S / C ONCLUSIONS

Large lakes and wetland boundaries of the Coteau des Prairies and There were three main data elements used to create this map. The assembly of the map components began with coordinate system. surrounding region have changed since the National Wetlands 1. Digital Elevation Model All map coverages were projected to USA Contiguous Albers Equal Inventory (NWI) dataset was developed approximately 30 years ago. 2. National Wetlands Inventory Area Conic USGS version. This was further customized adjusting the Landsat 8, a NASA and USGS collaboration, acquires global moderate- 3. Landsat 8 data. Central Meridian to: -97.5°, Standard Parallel 1 to 29.5°, Standard resolution measurements in the visible, near-infrared, short wave, and Parallel 2 to 45.5°, and the Latitude of Origin to 23.0°. thermal infrared. Boundary limits for large water bodies were updated using 2016 Landsat 8 imagery with less than ten percent cloud cover. The mosaicked 1/3 arc-second DEM resulted in a cell resolution 10 Unsupervised and supervised classification methods were used to 1. Digital Elevation Model meters. extract water features from Landsat 8 imagery using ArcGIS Pro Imagery tools. Extracted polygon features were manually edited and • 30 National Elevation Dataset Clipped NWI data provided a total of 1,652,089 basins within the study overlaid with the NWI dataset. A final map was created by overlaying (NED) 1/3 arc-second DEMs area. This data included all of the temporary, seasonal, semi- water body features on the 3D Elevation Program (3DEP) Digital were downloaded and permanent, permanent wetland basins. There were 80,300 basins that Elevation Model (DEM). mosaicked together in ArcGIS were derived from the unsupervised classification of the Landsat 8 10.5 (Figure 3). data. Most of these basins were classified as large permanent or semi- • DEM was then clipped to study permanent. extent. S T U D Y A REA • Color ramp was created. Large features showed significant change between NWI data and the Figure 3: Digital Elevation Model, Landsat 8 unsupervised classification. Figure 4 shows NWI data The Coteau des Prairies is a plateau approximately 200 miles in length 2. National Wetlands Lake Waubey Region. boundaries for the Lake Waubey region in . Compared to and 100 miles in width (320 by 160 km), rising from the prairie flatlands in Inventory Figure 5, which shows the boundary changes resulting from the Landsat eastern South Dakota, southwestern Minnesota, and northwestern 8 land/water extraction. Iowa.. • National Wetlands Inventory data were downloaded by state Figure 6 for Iowa, Minnesota, Nebraska, Landsat data Landscape , and South was overlaid Dakota. on NWI. • During the last (Pleistocene) • Datasets were merged and The final map , two lobes of the clipped using ArcGIS 10.5 (Figure was created Laurentide glacier, the 4). by overlaying James lobe on the west wetlands on and the Des Moines lobe • Table of NWI data was sorted by the DEM. on the east, appear to code and a new category was have parted around the created for permanence type. Figure 4: National Wetlands Additional Inventory, Lake Waubey Region. pre-existing plateau and • The NWI Wetland Code cartographic further deepened the Interpreter was used to identify elements lowlands flanking the wetland types. were added plateau (Cline et al: • Queries were made on basin to finish the 2015)(Figure 1). codes and permanence types map (Figure • The lowland is were labeled as Temporary, 7). between the two plateau Seasonal, Semi-permanent, regions known as the Permanent, or Riverine. Coteau du Missouri and the Figure 1: Extent of glaciation ~ 13,800 Coteau des Prairies. This radiocarbon years before present. narrow area was formed by (Adapted from: Cline et al (2015)). 3. Landsat 8 Imagery the James lobe of the Laurentide Ice Sheet. • Selection of Landsat 8 imagery • Northern prairie wetlands was limited to images with less Figure 5: Landsat 8 boundaries, were formed ~10,000 years than 10% cloud cover during Lake Waubey Region. Figure 7: ago. The decaying ice 2016. Completed map. sheet left behind • An unsupervised classification depressions formed by the was performed on imagery uneven deposition of till using ArcGIS Pro 2.0 Imagery and ground moraines. Classification Wizard. R EFERENCES/DATA • Landsat 8 bands 5 6 4 to Cline, Mitchell D, Neal R Iverson, and Chris Harding. "Origin of Washboard Moraines of the Des Map Boundaries determine Land/Water. Moines Lobe: Spatial Analyses with LiDAR Data." Geomorphology 246 (2015): 570-78. • Areas identified as water were • The north-south bounding Data sources: coordinates are between saved as grid for each image U.S. Fish & Wildlife Service, National Wetlands Inventory, Wetlands Mapper. N42°30’00” and N46°00’00’. (Figure 5). URL: https://www.fws.gov/wetlands/data/mapper.html. • Small basin features were U.S. Fish & Wildlife Service, NWI Wetland Code Interpreter. The east-west bounding URL: https://www.fws.gov/wetlands/data/wetland-codes.html. coordinates are between removed. Larger basin features USGS EROS Center, National Map W95°00’00” and were overlaid on NWI data Figure 6: Landsat 8 boundaries and URL: https://viewer.nationalmap.gov. W100°00’00” (Figure 2). Figure 2: Study area. (Figure 6). National Wetlands Inventory, Lake USGS Earth Explorer Waubey Region. URL: https://earthexplorer.usgs.gov.