Waterline digital elevation model development to quantify inundation duration and coastal protection of tidal wetlands

Shang-Shu Shih; Wei-Chuan Hsu; Yao-Wen Hsu

doi:10.1016/j.scitotenv.2023.162519

Waterline digital elevation model development to quantify inundation duration and coastal protection of tidal wetlands

Sci Total Environ. 2023 May 20:874:162519. doi: 10.1016/j.scitotenv.2023.162519. Epub 2023 Mar 2.

Authors

Shang-Shu Shih¹, Wei-Chuan Hsu², Yao-Wen Hsu²

Affiliations

¹ Department of Civil Engineering, National Taiwan University, Taiwan; Hydrotech Research Institute, National Taiwan University, Taiwan. Electronic address: uptreeshih@ntu.edu.tw.
² Department of Civil Engineering, National Taiwan University, Taiwan.

PMID: 36870502
DOI: 10.1016/j.scitotenv.2023.162519

Abstract

Coastal tidal wetlands are sufficiently acknowledged for the supplied vital ecosystem functions, including flood protection and biological conservation. Measuring and estimating reliable topographic data is essential for quantifying mangrove habitat quality. This study proposes a novel methodology for quickly constructing a digital elevation model (DEM) with an instantaneous waterline combined with tidal level records. Unmanned aerial vehicles (UAVs) enabled on-site waterline interpretation analysis. The results show that image enhancement improves the accuracy of waterline recognition and object-based image analysis has the highest accuracy. The waterline DEM (WDEM) performs a more accurate elevation production than UAV DEM, indicating that its application to habitat evaluation and prediction could be more reliable. Hydrodynamic simulations incorporated with the mangrove habitat model were utilized to calculate inundation duration, flow resistance, and vegetation dissipation potential according to the verified WDEM. The larger the mangrove coverage ratio, the stronger the flow resistance, which means that the protective consequence of the mangrove on the natural embankment is evident. The WDEM and nature-based solutions presented facilitate an adequate understanding of coastal protection and promote the potential ecosystem-based disaster risk reduction of mangrove wetlands.

Keywords: Digital elevation model; Ecosystem-based disaster risk reduction; Nature-based solution; Unmanned aerial vehicle; Vegetation dissipation potential; Waterline.