ANALYZING ENVIRONMENTAL AND GEOMORPHIC FLOOD IMPACTS USING ANNUAL DIGITAL AERIAL IMAGERY

Geology faculty and students at Northwest Missouri State University are using an annual series of aerial imagery to monitor and analyze flood impacts on local river systems. During each of the last four years, intense spring storms triggered at least one major flood event on the One Hundred Two (102) and Nodaway Rivers in northwest Missouri. Resulting increase in river stage and stream flow caused substantial inundation of adjacent floodplain areas as well as increased erosion within the channel environment.

Various digital change detection techniques were employed by faculty and student researchers through a series of continuing studies to identify both environmental and geomorphic impacts to these river systems. Analysis was facilitated by obtaining yearly digital aerial imagery generated as part of the United States Department of Agriculture’s (USDA), National Agriculture Inventory Program from the Missouri Spatial Data Information Service website. Once downloaded, the imagery was then processed and analyzed using various tools available in the ESRI ArcGIS^® software program.

Impacts and changes observed include: 1) locating areas of increased overbank sedimentation; 2) channel bank loss; and 3) dramatic shifts in channel morphology. Specific results show high levels of sedimentation variability relative to the presence or absence of sand mounds and ridges; bank loss amounts exceeding 17 meters during a single study year and substantial shift in channel configuration due to these extreme flooding events.