Part of the Southeast Aquatic Resources Conservation Science and Practice Webinar Series, sponsored by the U.S. Fish and Wildlife Service Southeast Region. To see other webinars in this series, visit http://www.fws.gov/southeast/webinars/.
Landscape scale assessment of floodplain inundation frequency using Landsat imagery
Wednesday, January 11, 10:00 am ET
In large river ecosystems, the timing, extent, duration and frequency of floodplain inundation greatly affects the quality of fish and wildlife habitat and the supply of important ecosystem goods and services. Seasonal high flows provide connectivity from the river to the floodplain and seasonal inundation of the floodplain governs ecosystem structure and function. River regulation and other forms of hydrologic alteration have altered the connectivity of many rivers with their adjacent floodplain – impacting the function of wetlands on the floodplain and in turn, impacting the mainstem river function. Conservation and management of remaining floodplain resources can be improved through a better understanding of the spatial extent and frequency of inundation at scales that are relevant to the species and/or ecological processes of interest. Spatial data products describing dynamic aspects floodplain inundation are, however, not widely available. This study used Landsat imagery to generate multiple observations of inundation extent under varying hydrologic conditions to estimate inundation frequency. Inundation extent was estimated for 50 Landsat scenes and 1334 total images within the Gulf Coastal Plains and Ozarks Landscape Conservation Cooperative (GCPO LCC), a conservation science partnership working in a 730,000 km2 region in the south central United States. These data were composited into a landscape mosaic to depict relative inundation frequency over the entire GCPO LCC. An analytical methodology is presented for linking the observed inundation extent and frequency with long-term gage measurements so that the outcomes may be useful in defining meaningful critical thresholds for a variety of floodplain dependent organisms as well as important ecological processes.
Yvonne Allen* (Gulf Coastal Plains and Ozarks Landscape Conservation Cooperative and USFWS – Baton Rouge, LA)