The United States Department of Agriculture (USDA) Delta Region Areawide Aquatic Weed Project (DRAAWP) has, as one of its purposes, to enhance and implement the rollout of new, innovative, or unique processes to support finding and controlling aquatic invasive species. It is using that overarching theme that the process described below was conceived.
Weed mapping researchers have long sought methods to better quantify floating aquatic vegetation (FAV) using global information systems (GIS) within specific areas. California State Parks Division of Boating and Waterways (DBW) manages aquatic invasive species on 69,000 acres of the Sacramento-San Joaquin Delta. DBW has identified more than 300 treatment sites in a multitude of waterways and sloughs. In addition, DBW has begun actively managing aquatic invasive species on 30,000 acres of the Suisun Marsh.
One goal of DRAAWP is to determine the most efficient, cost-effective method for quantifying the extent of aquatic invasive species within the Delta and surrounding tributaries. By quantifying FAV, DBW can gain a better understanding of the total extent of the problem and the efficacy of management efforts. The use of satellite imagery can yield fast and improved data, and reduces the need to manually encircle polygons of FAV from graphical imagery, which can be tedious, error prone, and over time, subject to carpal tunnel syndrome.
Therefore, a completely new way of discerning FAV across the total treatment area has been developed. DBW formed a partnership with NASA to use biweekly USGS Landsat 8 Imagery and image classification methods to produce a dynamic PDF document showing all target sites in the greater Sacramento Delta. Outputs include FAV percent coverage and projected biomass. Environmental scientists and field personnel are currently ground truthing this dynamic PDF for accuracy. It is expected that this tool will ensure that program staff are aware in real time of the abundance of floating aquatic vegetation throughout the Delta, and are therefore able to quickly and efficiently respond to problem areas.
Ralph Jaggi is a Research Analyst with California State Parks Division of Boating and Waterways, Sacramento.