Keynote Presentation Australian Marine Sciences Association 2025 Conference

Understanding sea-level and coastal change: Implications for sustainable management (120762)

Stephen Chua 1 , Abang Nugraha 1 , Andrew Green 2 , Uri Schattner 3 , Doug Slogrove 2 , Yu Ting Yan 1 , Isaac Lai 1 , Koi Siek 1 , Benjamin Horton 1 4
  1. Nanyang Technological University, Earth Observatory of Singapore, Singapore
  2. University of KwaZulu-Natal, Geological Sciences, School of Agricultural, Earth and Environmental Sciences, South Africa
  3. University of Haifa, School of Environmental Sciences, Israel
  4. Nanyang Technological University, Asian School of the Environment, Singapore

Modern coastlines of Singapore sit upon late Quaternary sediments formed by sea-level fluctuations over glacial/interglacial cycles. Here we review the current understanding of past sea-level change driving coastal evolution in Singapore, show recent field-based measurements constraining present-day coastal processes and suggest implications for future sustainable management of coastal resources.

We conducted a comprehensive geophysics survey of the Singapore Strait, conducted sediment and water sampling surveys coupled with sedimentological and geochemical analysis. The geophysics reveal that the south-eastern palaeoshoreline of Singapore extended up to 5 km beyond the modern coastline at ~14 ka BP. Continued rapid sea-level rise (SLR) at rates > 15mm/yr drove deposition of sedimentary units associated with coastal geomorphic features including coastal plains, palaeochannels and estuarine environments. SLR decelerated from ~15 mm/yr to ~4 mm/yr by 8 ka BP, producing a series of fluvio-deltaic sequences. Coastal impacts by 20th and 21st century SLR rate of 1–4 mm/yr were mitigated by geoengineering and land reclamation leading to changes to fore- to offshore gradients and seabed sedimentology and morphologies, primarily. We aim to further investigate coastal changes over short timescales to understand process driving localised coastal change to inform sustainable management of coastal regions.