Water depth retrieval models of East Dongting Lake, China, using GF-1 multi-spectral remote sensing images

High-resolution satellite technology is playing an increasingly important role in environmental monitoring. As the first high-resolution satellite for earth observation in China, GaoFen-1 (GF-1) has great potential for collecting water depth data. Multispectral images from GF-1 (16 m) combined with water depth data from long-term monitoring at a hydrological station were used with the normalized difference waterbody index, density segmentation, band combination, models (single-band, multi-band, and dual-band ratio) to invert the water depth of East Dongting Lake in the dry season and to provide important references for remote sensing of water depth. The experimental results are as follows. (1) Red, green, blue, and combined bands had higher correlation with the measured data. Consequently, the green band was chosen as the factor in the single-band model; blue, green, and red bands in the multi-band model and the ratio of green to red bands in the dual-band ratio model. (2) The correlation coefficients of measured data and single-, multi-, and dual-band models were 0.848, 0.867, and 0.925, respectively. (3) The inversion results showed that average water level in East Dongting Lake was approximately 20 m in the dry season during the period 2013–2016 and it was highest in southern area, intermediate in eastern area, and lowest in the western area.