Monitoring extreme environmental conditions in wetland macrosystems using optical and RADAR satellite data

SALVIA, MARÍA MERCEDES; KANDUS, PATRICIA; BORRO, MARTA; KARSZENBAUM HAYDEE

Cuiabá, Brasil

Conferencia; 8th INTECOL Wetland Conference; 2008

INTECOL

The Paraná river Delta is a wetland macrosystem that stretches through the final 300 km of the Paraná basin and covers approximately 17,500 km2. The last two years (summer 2007 and early autumn 2008), this region suffered from extreme environmental events: flooding and drought. This last event contributed to the expansion of strong fires that affected the region and large cities such as Buenos Aires and Santa Fe were covered by smoke for several days causing serious traffic accidents and health damage.  During the flooding event (summer 2007) large cattle raising areas of the region were seriously affected and about 200000 cows had to be moved rapidly to avoid animal deaths and important economic losses.This region includes a complex mosaic of landscapes resulting from past and present fluvial and coastal hydrogeomorphological process. It also has a complex hydrological regime mainly determined by the influence of the Paraná and Uruguay rivers, De La Plata estuary tidal regime and local rain. It is well known that optical satellite is very useful to determine vegetation types, but unable to map underlying waters. Microwave sensors on the other hand can penetrate vegetation and, in particular, synthetic aperture radars sensors (SAR) have been successfully used to map inundation condition of wetlands vegetation and water level within floodplains.Several ENVISAT ASAR Wide Scan C band HH polarization images were acquired  over the area during the periods mentioned above and used to assess changes in soil condition (only temporally flooded, permanently flooded, non flooded, dry) of different vegetation structures and to determine permanent and non permanent water bodies (mainly lagoons).Field work, helicopter and airborne flying, hydrological data, a regional land cover map obtained with optical data and radar change detection techniques were used to assess variations in inundation condition of dominant vegetation structures and land water bodies and extent of burned vegetation.