On-Site Investigations of Coastal Erosion and Accretion for the Northeast of Taiwan

Abstract

Coastal erosion is a major natural hazard along the northeastern shoreline (i.e., Yilan County) of Taiwan. Analyses of the evolution of the 0 m isobath of the Yilan County coastline indicate that erosion and accretion are occurring north and south of Wushi Fishery Port, respectively, because of jetty and groin construction. Topographic and bathymetric surveys involving the measurement of 43 cross sections were conducted in 2006, 2012, 2013, and 2019. The cross-shore profile comparisons reveal that the erosion of onshore dunes is significant in the northern Jhuan River estuary. Due to the establishment of a nature reserve in the southern Lanyang River estuary, the sediments are carried northward by tidal currents, and accretion is inevitable in the northern Lanyang River estuary. The results of the bathymetric surveys also suggest that the shoreline of Yilan County tends to accrete in summer because of abundant sediment from the rivers; however, it is eroded in winter, owing to the large waves induced by the northeast monsoon. Additionally, the calculated net volume of erosion and accretion between each pair of cross sections shows that the length of coastline impacted by estuarine sediment transport is approximately 2 km long from north to south along the coastline of the Lanyang River estuary.

Analysis of Shoreline and Erosion Changes along the West African Coast from 1980 to 2020

“…In fact, this study did not take into account the local changes caused by coastal defense structures. Cross-profile comparisons with bathymetric surveys in Taiwan showed that because of jetty and groin construction, erosion as well as accretion are observed [32]. In combination with sediment budget calculations, satellite images, drone and local video cameras, Angnuureng et al showed that no landward recession has been observed at Elmina beach in Ghana thanks to sea defense structures [33].…”

The change of coastal typology in Bali Island Karst Region at southern formation

“…Reclamation offshore throughout the 2017 and 2022 cause the changing coastline resulting in accretion and coastal erosion in the area. Derived from some research, basically all human activities bring bad situations to the coast including disaster from coastal erosion that happened both land and sea [41][42][43][44]. Cutting the cliff from the structurally shaped coast which also brings the material to the coast which can cause accretion that happened in the beach because of sediment transportation when the landscape changes [45] to become land erosion coast such as in Melasti Beach.…”

Storm Tide and Wave Simulations and Assessment II

“…For the on-site investigation of coastal erosion and accretion for the northeast region of Taiwan, Liang et al [5] investigated coastal erosion and accretion in that area through a series of on-site surveys. The results of the bathymetric surveys suggest that the shoreline of Yilan County tends to accrete during the summer because of abundant sediment from the rivers; however, the shoreline is eroded in winter due to the large waves that are induced by the northeast monsoon.…”