Scientists have developed a calculator that can guide coastal planners on the height and positioning necessary for infrastructure to avoid inundation and erosion as sea levels rise. The webtool, called Canute – the Sea Level Calculator, will estimate the necessary elevation for infrastructure on hard shorelines. In the case of soft shorelines the webtool will estimate the distance infrastructure needs to be set back from the water to avoid shoreline recession. In developing Canute - the Sea Level Calculator, scientists looked at data from tide gauges and storm surge modelling at 12,000 points roughly every 2.5 kilometres around the Australian coast. The software was developed by sea-level scientists Dr Steve George and Dr John Hunter, of the ACE CRC. Dr George said Canute assessed the likelihood of inundation from the sea based on two parameters. “We have developed a statistical technique that combines the uncertainty of how often a storm surge or very high tide is going to occur with the uncertainty of the extent of future sea-level rise. This technique combines those into a single likelihood,” he said. “The beauty of Canute is that it now has a suite of calculators that allow coastal planners to estimate a range of factors, such as waves and tropical cyclones, that can impact on the positioning of infrastructure.” To use the inundation calculator users select the location on a Google Maps interface, before selecting a greenhouse gas emission scenario and the time frame over which the assessment is to be made (generally the lifetime of the asset). The possible future greenhouse gas emission scenarios are taken from the Intergovernmental Panel on Climate Change’s Third and Fourth Assessment Reports (2001 and 2007). Two graphs are generated - one showing coastal flooding probability under a rising greenhouse gas scenario, the other projecting the probability if sea level remained where it is today. The work expands on the ACE CRC’s previous sea-level rise planning tool, which has been in use since 2009 but could provide projections for only 29 sites around the Australian coast. Canute – the Sea Level Calculator was developed with funding from the Department of Climate Change and Energy Efficiency. The engineering firm pitt&sherry and SGS Economics and Planning assisted in the development of the tool and are using it in their work. Mr Sven Rand, pitt&sherry's Program Leader – Climate Change Adaptation , said the company routinely used sea-level inundation calculations in infrastructure asset design as well as in planning processes where consideration of coastal vulnerability was required. “Canute provides valuable information on both the present likelihood of inundation and a range of potential future scenarios,” Mr Rand said. “The recently added capabilities mean that the tool assesses the full range of factors that contribute to storm tide inundation and erosion, providing a highly valuable overview. This tool provides us with the specific information on sea-level rise vulnerability that needs to be considered in the planning and design of coastal assets.” Nathan Fabian, the chief executive of the Investor Group on Climate Change, formally launched Canute – the Sea Level Calculator in Melbourne on October 23. Go to the Canute website: www.sealevelrise.info.

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