Abstract:

Water hyacinth (Eichhornia crassipes) is a notorious weed that can be found in large parts of
the tropical world. It infested East African fresh water lakes in the 1980's, soon causing major
problems on notably Lake Victoria. Mats consisting of water hyacinth blocked ports along the
shoreline of the lake, the generation of hydro-electricity was hampered and the already
disrupted ecosystem was further affected. Acontrol program has been initialised, that requires
objective and efficient information. The ways to get information about the exact location and
the size of the water hyacinth mats need to be improved. The application of remote sensing
techniques can realise this improvement.
SYNOPTICS and FIRI have carried out a project to investigate the potentials of spaceborne
Synthetic Aperture Radar to detect water hyacinth mats on Lake Victoria. ERS, Radarsat and
SIR-C data were acquired to evaluate the different sensors. The evaluation showed that in
particular Radarsat data are well suited to identify and map the mats. New sensors, both in
the optical range and the microwave range, make the perspective of a monitoring program
based on remote sensing techniques even better