Abstract: With the development of unmanned aerial vehicle (UAV) and new aerial photography technologies, UAV tilt photography technology has played an important role in the acquisition of large-scale terrain data, and research related to 3D mapping has been greatly promoted. However, there are relatively few studies on the integrated production process of water terrain and underwater terrain required by the water conservancy industry. This paper sets up a unified control point, uses fixed-wing UAV tilt photogrammetry to survey the terrain on the water, and uses RTK in conjunction with a depth sounder to collect three-dimensional terrain data on the river. For river-related buildings, BIM software is used for parameterization mold. Finally, fusion processing is performed on the water terrain data, the underwater river terrain data and the three-dimensional model of the building to obtain the integrated three-dimensional river scene of the water and underwater, and the Cesium platform is built for three-dimensional display. The research results can provide technical assistance for integrated mapping and visualization of water and underwater, and help promoting the evolvement of smart irrigation works applications.

Key words: UAV tilt photography, BIM, water and underwater integration, Cesium platform, river scene