Through a partnership with National Aeronautics and Space Administration (NASA), as a part of the U.S. Department of Agriculture – Agricultural Research Service (USDA-ARS) Delta Regional Areawide Aquatic Weed Project (DRAAWP), NASA has developed Floating Aquatic Vegetation (FAV) mapping tools intended for operational use by DBW. An initial tool based on the Landsat Satellite provided Division of Boating and Waterways (DBW) with map imagery from satellite data that depicted live water hyacinth and water primrose acreage of areas with 30-meter pixels at approximately 14-day intervals. The FAV Mapping Tool is being modified to utilize a new satellite, Sentinel-2, with increased spatial and spectral resolution as well as greater frequency. Imaging at approximately 5-day intervals helps to avoid interruption in schedule due to weather, clouds and smoke.
DBW specialists have been reviewing the new mapping tool output during routine operations in the Delta. On August 13, 2019, Senior Environmental Scientist (Specialist) Jon O'Brien and Senior Environmental Scientist (Supervisor) Angela Calderaro of DBW, along with Senior Research Scientist Dr. David Bubenheim with the NASA Ames Research Center conducted a field evaluation of the map output and specialist comments to evaluate consequences of smaller pixel size and increased spectral resolution with Sentinel-2.
Some key finds were: 1) large algal patches may be identified separately from FAV (definition continues), 2) confirmation that smaller FAV patches remain uniquely identifiable among larger populations of upright emergent aquatic plants (Rush/Tule), and 3) the smaller pixel size has highlighted areas where terrestrial plant canopies lining levees project beyond the digital levee border and where they are present growing in areas of significant sediment well within the defined water area as indicated by the levee boundary and register as FAV. The smaller pixel size provides a much-improved ability to identify smaller patches of FAV than previously possible. The areas where terrestrial plants are present within the water area of the digital levee boundary are being identified and options for incorporating into the FAV Mapping considered.
Once finalized, this new tool will help identify and quantify patches of FAV for operational and planning needs as well as measuring the effectiveness of treatment methods over time.
This project was funded in part by the Delta Region Areawide Aquatic Weed Project (DRAAWP).