Standard Presentation Australian Marine Sciences Association Annual Meeting 2023

Climate Change Induced Coastal Flooding in the Georges River Estuary, Sydney, New South Wales, Australia (#257)

Wenjun Zhu 1 , Xiao Hua Wang 1 , William Peirson 2
  1. The Sino-Australian Research Consortium for Coastal Management, School of Science, UNSW Canberra, The University of New South Wales, Canberra, ACT, Australia
  2. Water Research Laboratory, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales, Australia

Estuaries are impacted by both oceanic and catchment forcings. Estuarine systems are complex, dynamic and particularly vulnerable to climate change. The impacts of climate change-induced extreme flooding in the Georges River estuary which flows through one of the most urbanized areas in Australia. Geomorphological changes, ecosystem impacts and potential economic losses caused by floods in estuaries are potentially very significant. Assessment of flooding changes requires rainfall-runoff model simulation to develop extreme flood hydrographs. In this study we have used an event-based hydrologic model, the Watershed Bounded Network Model (WBNM). After calibrating WBNM for recorded flood events, rainfalls derived from NARCliM (the New South Wales and Australian Capital Territory Regional Climate Model) have been used to assess extreme rainfalls under climate change. Increases in rainfall at the 50 year Average Recurrent Interval are projected to be 25% with significantly greater consequent increases in runoff and flooding.