Why do we continue to allow development in floodplains? A study in the USA found that coastal communities have recently built tens of thousands of houses in areas at risk of chronic future flooding driven by sea level rise from climate change. Since 2009, new homes added inside of America’s highest coastal flood-risk zones outpaced the percentage growth rate outside of those areas — in more than half of the country’s coastal states. As reported in this edition of Floodplain Manager, it was found for Hurricane Harvey in Houston that increased urbanisation can even influence the amount of precipitation that falls across the floodplain. I have just returned from the Philippines and in that developing country urbanisation including slum development continues uncontrolled in floodplains and coastal areas prone to tsunamis and storm surge from typhoons. This is particularly pronounced in Greater Manila, a conurbation with a population greater than the whole of Australia. Here, although authorities have developed warning systems in many of the flood-prone districts and regularly engage with barangays (communities), increased flood exposure due to population increase outstrips structural and non-structural mitigation efforts.
And Australia has not been able to contain development in many of its floodplains. This is particularly the case in metropolitan and peri-urban parts of the country. For example, the population in the Hawkesbury-Nepean floodplain in Western Sydney is expected to grow by over 7% in the next twenty years. This increased exposure will partially offset the mitigation gains achieved by the raising of Warragamba Dam. And this coming, as reported in this edition of Floodplain Manager, when due to climate change-induced increasing atmospheric temperature, it is predicted in Australia that there will be an increase in heavy rainfall events and an increase in flash flooding as a result.
As floodplain managers we need to remind town planners and developers alike of the risks of future development in floodplains. Particularly in high risk areas, planned retreat should be considered, rather than increasing the urban footprint.
Vale Jim Bodycott
Jim Bodycott passed away on 8 November, 2018. Jim was a significant figure in floodplain management in Australia and in NSW in particular. He studied civil engineering as a cadet with NSW Public Works in 1968 and eventually found himself working on the planning and design of flood mitigation schemes. He became passionate about flood mitigation and had significant input into the 1986 NSW Floodplain Development Manual which was a ground breaking publication at the time. After the floodplain and coastal management sections of Public Works were moved into the newly created Department of Land and Water Conservation, Jim continued to work in floodplain management in that and the subsequent incarnations of the organisation. He was an active member of Floodplain Management Australia (FMA) as it is now called and forged links with the Association of State Floodplain Managers in the USA. After his retirement in 2002, he continued his interest and involvement in floodplain management. His friends and colleagues have commented that Jim looked after the people working with him and is remembered as a caring, friendly and approachable man who was widely respected not only by his fellow professionals, but equally by all members of the FMA, NSW State Emergency Service, industry groups and landholders.