Water Surface Monitoring of Qingtongxia West Main Canal by Sentinel-2 Satellite Observations

The knowledge and understanding of intra- and inter annual characteristics of canal water is crucial for agricultural water management. The narrow shape of canal greatly limits the application of moderate-resolution remote sensing technologies. Based on newly available Sentinel-2 Multispectral Instrument (MSI) imagery with frequent revisit and higher spatial resolution, we identified variation of water/bank boundary by Roberts, Sobel, Prewitt, Laplacian of Gaussian and Canny 5 edge detectors and furtherly compared the water width results with estimation by ground measurement. The preliminary results show that all detectors can successfully monitor seasonal variation of canal water surface. Canny detector is most stable among 5 methods for time series monitoring, although overestimated the water width during dry period. Our methods and results reveal the great potential of Sentinel-2 imagery for canal water utilization and irrigation management.