Impacts of Sea Level Rise and River Discharge on the Hydrodynamics Characteristics of Jakarta Bay (Indonesia)

Martin Yahya Surya,Yuezhang Xia,Li Li,Zhiguo He

doi:10.3390/w11071384

Martin Yahya Surya, Yuezhang Xia + Show 2 more

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https://doi.org/10.3390/w11071384

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Abstract

Jakarta city has been vulnerable to sea level rise and flooding for many years. A Giant Seawall (GSW) was proposed in Jakarta Bay to protect the city. The impacts of sea level rise and river discharge on the tidal dynamics in Jakarta Bay and flooding areas in Jakarta city were investigated using the finite-volume coastal ocean model (FVCOM). Model results showed that the bay is diurnally dominated by the K1 tidal component. The diurnal tides propagate westward, while the semidiurnal tides propagate eastward in the bay. The rise of sea level increases the diurnal tidal component and the inundation areas due to the increased tidal forcing: when considering a sea level rise of 0.6 m, the K1 amplitude increases by ~1% (0.25 cm) near the coastline and the current magnitude increases by 16.6% (0.05 m/s). The inundation area increases with the sea level rise in the low land elevation areas occurring near the coastlines: the inundation area increased by 29.68 km2 (7.1%) with a sea level rise of 0.6 m. The increase of river discharge amplified the diurnal tidal component as well as the inundation areas at the river mouth due to increased fluvial forcing: if 10 times the mean river discharge occurs, the K1 amplitude increases by ~1% (0.25 cm) and the current magnitude increases by 100% (0.4 m/s), and the inundation areas increase by 26.61 km2 (6.2%). The K1 tidal phase remains almost unchanged under both the sea level rise and river discharge conditions. The combined increase of sea level rise and the river discharge amplifies the inundation areas and the tidal currents due to increased tidal and fluvial forcing. The construction of GSW would decrease the tidal prism and dissipation effects of the bay, thus slightly increasing the K1 amplitude of the tidal level: by less than 1% (0.2 cm). There would be no significant change of phase lag for the K1 component. Although this study is site specific, the findings could be applied more widely to any open-type bays.

Highlights

Jakarta Bay is located on the northwest coast of Java Island, extending from 5.8◦ S to 6.2◦ S and106.6◦ E to 107.1◦ E [1]
The different propagation pattern of diurnal and semidiurnal components is caused by the topography of Jakarta Bay, as the bay is located at the Java Sea and near to the Sunda Strait
Ray et al (2005) [32] reported that the semidiurnal response is clearly dominated by the large tides from the Indian Ocean, while, in contrast, the diurnal tides come from the Pacific Ocean

Summary

Introduction

Jakarta Bay is located on the northwest coast of Java Island, extending from 5.8◦ S to 6.2◦ S and. 106.6◦ E to 107.1◦ E [1] It is a shallow bay with an average depth of about 18 m and an area of. Jakarta Bay is essential for the development of Jakarta city, the capital city of Indonesia. Jakarta city is the economic, cultural and political center of Indonesia. There are 10 million people in Jakarta city and more than 28 million people in the satellite cities of Jakarta [3]. The large population and the rapid development of the city have brought increasing urban development issues. The demographic change influenced by the urbanization causes large-scale rural land conversion and new town development in

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