Assessing low-relief coastal estuaries watershed boundary and its surface water flow based-on lidar-derived digital elevation models: a case study of Jiangsu

Conventional hydrologic analyses of digital elevation models (DEMs) perform well in areas of high topographic relief, where surface water flow is typically unidirectional, convergent, spatially static, and directed toward a single discharge point at the edge of a catchment. Such analyses do not perform well on landscapes with low topographic relief such as estuaries areas. where surface water flow is influenced by subtle topographic depressions and sea-land interaction, which may be bidirectional, divergent, and spatially dynamic in response to hydrologic forcing such as tides or variation in river discharge. We developed a framework for hydrologic analysis of low-relief landscapes using a high-resolution (0.2m) DEM derived from light detection and ranging (LIDAR) data collected over a Jiangsu Radiate Sand Ridges, China. Our approach assessed the pattern and characteristics of estuaries watershed and its hydrologic response drainage, where drainage boundaries were defined by subtle topographic divides across the Salt-marsh.