Flood Extent Prediction from Lake Heights and Water Level Estimation from Flood Extents Using River Gauges, Elevation Models and Envisat Data

Water levels and water extents are essential information in flood monitoring and forecasting. Two experimental and complementary ways were explored in order to estimate water level and water extent and forecast them: 1) The estimation of water level through combining water extents derived from earth observation data with elevation from a Digital Elevation Model; 2) The estimation of flood extents with respect to water levels by combining water levels recorded at a reference gauge station with the corresponding water extents derived from earth observation data. The results are very promising. The average error of estimated water level near the Hukou gauge station (north of the Poyang Lake) is about 1.26 meters using low and medium resolution ENVISAT products combined with 3 arc second SRTM DEM. Also, a first flood extent forecast map was estimated using ENVISAT low and medium resolution data and water levels recorded at Hukou gauge station.