Mapping submerged aquatic vegetation with hyperspectral techniques

The Saint John River is located in Florida and is a vital resource to the local community. The river system is managed by the Saint John River Water Management District (SJRWMD). The river supports a considerable growth of submerged underwater vegetation (SAV) and this vegetation is a good indicator of ecosystem health and provides feeding and nursery grounds for many animals. In addition the SAV adds dissolved oxygen to the river. It is important to note that the vegetated areas support almost three times the invertebrates as bare areas and SAV improves the habitat quality for invertebrates in both the sediment and water column. It is therefore very important as a management tool to be able to detect and map the location and extent of the SAV. However the river system is classed as a dark water river and it is very difficult to see through the water column. A pilot project using airborne hyperspectral methodology was conducted in 2003 to determine the effectiveness of using this method to map the SAV. The results were very encouraging and subsequent operational surveys have been conducted in 2006, 2008 and 2009. This paper will discuss the methodology used and will provide samples from the recent surveys.