Satellites assist planners preventing floods   An unidentified man tries to stop the water with sandbags in Sint-Denijs Westrem, Belgium, as water floods parts of the community after days of torrential rains, Friday, Jan. 3, 2003.   This diagram shows how model results compare with the reality of the flood on the river Demeter in January 1995. It is an overlay of an ERS SAR-derived flood map for 30 January 1995 (in yellow), with the existing Flemish map of peak floods for 1995 (in red) the MIKE 11 hydraulic flood simulation results for 30 January 1995 (in brown) and the MIKE 11 hydraulic flood simulation results at the peak moment (in blue).   Combining Earth Observation SAR data and flood simulation models to display likely flood return periods for a stretch of the river Dender. The area highlighted in green is likely to flood annually; the area in purple will most probably be revisited by floods within a decade, while the area in red is likely only to see floods once a century.   The Flemish Water Authority AWZ updated their flood risk mapping using high-resolution IKONOS data acquired as part of the FAME project. Here part of the river Dender is shown, the flood risk mapped in Euro divided by square metres divided by year. Risk maps are useful to insurance companies as well as the water authorities and local government.   This Envisat ASAR image acquired 0956 local time on 2 January 2003 of a flooded region shows the newer instrument's superior capability to detect flooded areas. Areas outlined in red or green are flooded. Compare its success rate to the ERS-2 SAR image taken at almost the same time (seen below).   This ERS SAR image acquired on 2148 local time on 2 January 2003 is not as successful at identifying flooded areas (shown within red and green outlines) than a comparable Envisat ASAR image (see above).   Envisat is in orbit at an altitude of 800 km - much too far for any astronaut to ever come visiting. But to glimpse what Europe's environmental satellite looks like in space, the German Research Establishment for Applied Science FGAN has used its Tracking and Imaging Radar (TIRA). It consists of a 34-metre parabolic antenna system with a narrowband L-band tracking radar and wideband Ku-band imaging radar providing high target resolution. The TIRA system is also used to image meteoroids and space debris. Release date: 22 June 2004