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Coastal managers frequently find themselves in a quandary. Actions taken in the past, sometimes legally sometimes not, have left behind legacies which today are noted for adverse effects. In a world of increased population growth and development in coastal locations and the threats posed by global warming, these legacy issues loom large in thinking how best they can be managed. These issues fall into the category of “wicked problems”. As such any attempt to “solve” such a problem will in most cases create new problems, or even worse exacerbate the harmful impacts of past actions.

There are several kinds of past actions which create problems for managers. Besides those that are illegal, there are many “approved” actions which over time authorities have realised have generated difficulties under present-day law or policy. Changes in the way societies approach development in coastal areas based on increased understanding of risk and harmful effects raises community and professional concerns as to what to do next. How best should the product of an apparent harmful action be ameliorated? Issues of removal, protection, cost, compensation, remediation, effects on adjoining land and waters, must all be assessed in a fair, equitable and transparent way. This is the case whether we are considering legacies of water pollution and toxic sediment deposition, drainage of wetlands and floodplains, habitat destruction due to sand mining or whatever, dredging and training of river and coastal lake entrances, diversion of freshwater away from estuaries, construction of seawalls or breakwaters that influence sediment transport, and building of property structures in low-lying areas even to and below mean high water mark. The list goes on, but around the Australian coast where urban development has progressed and will grow, we cannot avoid considering ways to address actual and potential harmful effects.

In a recent article published in the book edited by Derek Jackson and Andy Short (Sandy Beach Morphodynamics, Elsevier, 2020), entitled “Future challenges in beach management as contested places”, I provided examples from different coastal places where conflicts occur as a result of planning decisions or actions of self-interested parties that are highly problematic to public interests. Many of the examples stem from landowners seeking to protect their property “right”. Resulting court cases highlight the difficulty in resolving respective state and landowners interests even where the law in itself offers inadequate and contestable “solutions” (e.g. the Boggis case in Suffolk, U K, p. 725). In NSW, there have been many court actions related to impacts of unapproved seawalls, the latest of which occurred in 2018 at Byron Bay (Sack, Allen, and Thom, EPLJ, 37, 128-135, 2020). Here I served as a respondent on behalf of the Government. There are several other beachfront locations in NSW where past decisions to build coastal works, legal or not, have left behind permanent legacies of shoreline change that will continue to generate community and political debate (e.g. Stockton Newcastle).

Another legacy issue discussed in my article in the Jackson-Short edited book arises from the application of ancient common law principles, the Doctrine of Erosion and Accretion. This occurs where ambulatory boundaries in some way become “fixed” shoreline property boundaries. Angus Gordon, John Corkill and I have written about this contentious issue. In my article I show how several legal scholars in the USA see traditional interpretations as not fit for purpose in this new climate era of rising sea levels. The threat of future court cases looms large in many countries unless a more adaptive approach can be agreed to by contesting parties—good luck to that!

Another past category of action is the contamination of coastal waterways through the discharge of pollutants. Industrial activities around major estuaries, such as the Derwent in Tasmania, have left toxic legacies that will be with us for generations. Much effort has been spent in remediation here and elsewhere. Gavin Birch (University of Sydney), and his colleagues, have studied this issue in Sydney Harbour for many years. In a 2014 paper, he and Serena Lee write of improvements and continued challenges in securing a healthy estuary (S. Lee and G. Birch, “Sydney Estuary, Australia: Geology, Anthropogenic Development and Hydrodynamic Processes/Attributes” in E. Wolanski, ed., Estuaries of Australia 2050 and Beyond, Springer, 2014). They note improvements since the introduction of the Clean Waters Act 1970, and the relocation of heavy industry away from the waterfront. However, there is the ongoing threat posed with increased concentration of metals in sediments “due to rapid expansion of residential and commercial property and increased transport services” (p.21). Recent efforts to develop a more coordinated approach to managing the health of the Harbour and its catchments (Greater Sydney Harbour video) is indebted to the work of Birch and others who define in so many ways the nature and distribution of contaminants in these waterways.

There are many aspects of coastal wetland degradation that provide coastal managers with headaches. Wetland protection has been a subject of international (Ramsar), national (EPBC Act) and State (e.g. NSW SEPP 14, now in Coastal Management SEPP 2018) interventions. But there is one legacy that has long fascinated me, that is the threat to wetlands from exposure of acid sulfate soil (ASS) through the drainage of coastal floodplains. In essence these plains form as alluvial veneers over estuarine muds deposited in river valleys since sea level has been around its present position over last 6000-7000 years. Adventures in drilling into these sediments in the 1970s plus following the geological work of Peter Roy has given many of us a “feel” for the problem. I am indebted to Mike Melville, Robert Quirk, Will Glamore, and Mitch Tulau and others who have educated me on ASS problems. In particular, I was privileged to examine the PhD Thesis by Mitch (Southern Cross University) in which he documents the long history of drainage of floodplains to assist agricultural use and mitigate the impacts of property flooding. Costs to governments, farmers, fisheries, and the broader community of these extensive drainage schemes in the past will remain a legacy for decades to come.

We live with consequences of our history. That history must be understood and confronted in places where adverse impacts remain that cause harm to present and future generations. The way ahead as a result of trying to “manage” these legacies will never be easy; new knowledge, improved technologies, community awareness and political will all form the toolbox required to formulate “solutions” to such “wicked” coastal management problems.

Bruce Thom

Words by Prof Bruce Thom. Please respect the author’s thoughts and reference appropriately: (c) ACS, 2020. For correspondence about this blog post please email austcoastsoc@gmail.com