Coastal wetland investigations by airborne LiDAR: A case study in the Yellow River Delta, China

Coastal wetlands are considered the most biologically diverse of all ecosystems. Understanding their structures and functions is important for coastal environmental management and development. Airborne LiDAR (Light Detection and Ranging) has emerged as an effective tool for creating high-resolution digital surface models (DSM, highest elevation points) and digital terrain models (DTM, ground only points), which are vital geographic information sources for various applications in coastal areas, and investigating spatial patterns of vegetation in areas that are difficult to access. This paper investigates LiDAR's capability for mapping marine wetlands, extracting vegetation and channel networks, and identifying intertidal zones. The Yellow River Delta, China, was selected as a study site to conduct experiments. With only a 4.5-h flight, an area of more than 670 km2was surveyed with great detail. High-resolution DSMs and DTMs were generated, the vegetation coverage and heights were extracted using methods based on height and multireturn and the results were compared, and the water and tidal channels, which reflect the complete water transport system in the area, were mapped and measured. By combining LiDAR data and local tidal observations, the intertidal zone, which is a significant part of coastal wetlands, is clearly identified.