Fig. 1: Layout of the monitored aqueduct.

a Map showing the entire route of the Pearl River Delta Water Resources Allocation Project. The monitored test site is highlighted in red. Basemap ©Mapbox, ©OpenStreetMap. b Enlarged view of the monitored test site and DAS monitoring area over Google satellite imagery. Imagery ©2025 Airbus, Imagery ©2025 Airbus, CNES / Airbus, Landsat/Copernicus, Maxar Technologies, Map data ©2025.