1 Spatial Modelling of the Terrestrial Environment - Georeferencial

Flood Inundation Modelling Using LiDAR and SAR Data 97
Figure 5.4 Comparison of flood extent predicted by the LISFLOOD-FP inundation model
with a SAR-derived shoreline acquired in October 1998 during flooding on a 40-km reach
of the River Severn in Shropshire, west-central England downstream of the Montford Bridge
gauging station. Peak discharge at Montford Bridge was measured at 435 m 3 s –1 and the
recurrence interval of the event was estimated at 1 in 50 years. Over much of the domain the
model provides an excellent match to the SAR shoreline (solid black line) (from Horritt and
Bates, 2002). c○ Elsevier Science.
errors involved in predicting inundation for a design event from a model conditioned on
an historic inundation image. Moreover, in the next few years a number of new satellite
SAR systems will be available, e.g. ENVISAT, RADARSAT-2, ALOS and TerraSAR.
These may potentially provide a higher frequency of observation and their polarimetric and
high-resolution capabilities may offer improved prospects for detection and delineation of
flooded areas. Whether the frequency, resolution and accuracy of observations provided by
these systems will be sufficient to capture multiple images through a flood, and particularly
on the short duration rising limb, is still unclear.
For this reason, airborne SAR data is perhaps of even greater potential. Such data are of
higher resolution and potentially of much greater accuracy than that from satellite sources
and may thus be able to discriminate better between competing models. Model validation
studies thus need to be conducted using the existing airborne SAR data, which again at
best consist of two ‘snapshot’ images taken six days apart and do not properly capture