Analysis of Topographic Changes on Nusa Dua Beach Located in South Part of Bali Island

Coastal conditions and long-term topographic changes of Tanjung Benoa Beach on Bali Island, Indonesia

“…For understanding coastal mechanisms, it is essential to assess the long-term shoreline changes, particularly including the shoreline before anthropogenic modifications, and to estimate the rate of longshore sediment transport as quantitative data. The authors have studied shoreline changes and the rate of longshore sediment transport by using topographic data and using satellite images from 1997 to 2020 in Tanjung Benoa Beach in the previous study [10]. Figure 3 shows the aerial photographs and satellite images taken between 1997 and 2020 [10].…”

“…The authors have studied shoreline changes and the rate of longshore sediment transport by using topographic data and using satellite images from 1997 to 2020 in Tanjung Benoa Beach in the previous study [10]. Figure 3 shows the aerial photographs and satellite images taken between 1997 and 2020 [10]. By 1997, only GA8 was constructed with the remaining groins absent, and a semicircular sandbar presents in the north part of the study area.…”

“…By 1997, only GA8 was constructed with the remaining groins absent, and a semicircular sandbar presents in the north part of the study area. During The authors investigated the shoreline changes up to 2010, 2016, and 2020 with reference to that in 1997, as shown in Figure 4, which also shows the locations of groins (GA1-GN4) [10]. According to the shoreline changes, the shoreline advanced immediately south and retreated north of each groin, owing to the northward longshore sediment transport, which formed a zig-zag shoreline shape.…”

“…The rate of longshore sediment transport is calculated, by multiplying the rate of change in foreshore area and the height for sediment movement, h, which is a parameter combining the changes in cross-sectional area ΔA and the shoreline change Δy. The authors investigated the changes in longitudinal profile using topographical survey data from 2007 and 2021 [10], in the study area A, in Figure 1. Along six transects between GA1 and GA2, the changes in cross-sectional area ΔA and the shoreline change Δy with reference to HWL (LWL+2.70 m) were examined, and the correlation between the two variables was investigated.…”

“…Tanjung Benoa and Nusa Dua Beaches extend along the east coast of Bukit Peninsula on Bali Island, Indonesia (Figure 1). Along this coastline, a coral reef with an average water depth of MSL−1.0 m and width of 500 m to 700 m develops [1]. Northward longshore sediment transport prevails because of wave incidence from the southeast.…”