Keppel Bay is a large shallow coastal embayment adjacent to the mouth of the Fitzroy River, located on the central coast of Queensland. The geomorphology and distribution of sediment in Keppel Bay is complex due to the influence of Late Quaternary sea-level change, relict topography, a geologically diverse catchment, macrotidal hydrodynamic processes and flood events. Seabed morphology, sub-bottom profiles and sediment cores reveal the former path of the Fitzroy River across Keppel Bay and the continental shelf. The palaeo-Fitzroy River flowed west across the shelf to the north of Northwest Reef, a position on the shelf that is now under approximately 60 m of water. With the rise in sea level during the early Holocene, the mouth of the Fitzroy River retreated across the continental shelf and by the middle Holocene it was landwards of its present location, near Rockhampton. During the last few thousand years under a relatively stable sea level, much of the shallow inner region of Keppel Bay has been infilled and the coast has prograded several kilometres. Palaeochannels in the inner section of Keppel Bay have mostly been infilled with sediment, which mainly comprises muddy sand from the Fitzroy River. In the outer bay and on the shelf further west many relict channels have not been infilled with marine sediment indicating that the area is relatively starved of sediment. Sediments in outer Keppel Bay are dominantly relict fluvial deposits that are well sorted with only a minor mud component. Subaqueous dunes in the outer southeastern section of Keppel Bay and Centre Bank indicate that tidal currents and currents associated with the predominant southeasterly winds, appear to be transporting marine biogenic sediments and relict coarse terrigenous sediments into Keppel Bay.

The south-west coast of Western Australia is made up of a series of exposed limestone headlands which are prone to the development of cliff lines and large overhangs. Coastal processes such as wind and water erosion in conjunction with salt crystallisation and carbonate dissolution make these cliffs highly susceptible to collapse. The damaging impact that these unstable cliffs can have on the community was demonstrated on 27 September 1996, when four adults and five children were killed in a rockfall at Huzzas Beach, Gracetown.

This project was conducted by Geoscience Australia in collaboration with the Water Science Branch of the Department of Water, Western Australia, to acquire baseline information supporting the condition assessment for Hardy Inlet. The project contributes to the Estuarine Resource Condition Indicators project funded by the Strategic Reserve of the National Action Plan for Salinity and Water Quality / National Heritage Trust and forms part of the Resource Condition Monitoring endorsed under the State (Western Australia) Natural Resource Management framework. Two surveys were undertaken in Hardy Inlet in September 2007 and April 2008 with the aim to develop an understanding of the historical environmental changes and current nutrient and sediment conditions for the purpose of developing sediment indicators to characterise estuary condition.

The Australian Government, through the Department of Climate Change and Energy Efficiency, recognises the need for information that allows communities to decide on a strategy for climate change adaptation. A first pass national assessment of vulnerability to Australia's coast identified that considerable sections of the coast could be impacted by sea level rise. This assessment however, did not provide sufficient detail to allow adaptation planning at a local level. Accounting for sea level rise in planning procedures requires knowledge of the future coastline, which is still lacking. Modelling the coastline given sea level rise is complex, however. Erosion will alter the shores in varied ways around Australia's coastline, and extreme events will inundate areas that currently appear to be well above the projected sea level. Moreover, the current planning practice of designating zones with acceptable inundation risk is no longer practical when considering climate change, as this is likely to remain uncertain for some time. Geoscience Australia, with support from the DCCEE, has now conducted a more detailed study for a local area in Western Australia that was identified to be at high risk in the national assessment. The aim of the project was to develop a localised approach so that information could be developed to support adaptation to climate change in planning decisions at the community level. The approach included modelling a historical tropical cyclone and its associated storm surge for a range of sea level rise scenarios. The approach also included a shoreline translation model that forecast changes in coastal sediment transport. Inundation footprints were created and integrated with Geoscience Australia's national exposure information system, NEXIS, to develop impact assessments on building assets, roads and railways. Studies such as this can be a first step towards enabling the planning process to adapt to increased risk.

Replaced by 78873 Record 2014/003 (A Marshall 29/01/14)

TBA

The Australian National Coastal Vulnerability Assessment (NCVA) has been commissioned by the Federal Government (Department of Climate Change) to assess the risk to coastal communities from climate related hazards including sea-level rise, storm surge and severe wind from tropical cyclones. In addition to an understanding of the impact/risk posed by the current climate, we have also examined the change in risk under a range of future climate scenarios considering a number of periods up to the end of the 21st century. In collaboration with state and local governments and private industry, this assessment will provide information for application to policy decisions for, inter alia, land use, building codes, emergency management and insurance applications. The understanding of coastal vulnerability and risk is derived from a number of factors, including: the frequency and intensity of the hazard(s); community exposure and the relationship with stressors; vulnerability related to socio-economic factors; impacts that result from the interaction of those components; and capacity of communities, particularly vulnerable communities and groups, to plan, prepare, respond and recover from these impacts. These factors and resulting impacts from hazard events are often complex and often poorly known, but such complexity and uncertainty is not an excuse for inaction. Given these limitations, the NCVA has been undertaken using the best information available to understand the risk to coastal areas on a national scale, and to prioritise areas that will require more detailed assessment.

In April 2005, Geoscience Australia (GA) conducted a field survey of the waterbodies of the Torbay catchment drainage system. The Torbay Catchment Group and the Western Australian Department of Environment commissioned this study in order to address critical knowledge gaps in their understanding of the major components of the nutrient budget. In particular, the role of benthic nutrient fluxes, their magnitude, and total benthic nutrient supply to the water column for phytoplankton growth. The waterbodies studied were Torbay inlet, Lake Powell, Marbellup Brook and Lake Manarup. The key findings of this study were: 1. the sediments are a major source of nutrients to the water column of all waterbodies; and 2. denitrification, nitrogen fixation and benthic photosynthesis are critical processes influencing overall water quality.

Coastal communities in Australia are particularly exposed to disasters resulting from the coincidence of severe wind damage, storm surge, coastal flooding and shoreline erosion during cyclones and extra-tropical storms. Because the climatic drivers of these events are stronger during or across specific years (e.g. during La Nina periods), they can repeatedly impact the coast over periods of weeks, months or up to a few years. The consequences of individual events are therefore exacerbated with little or no opportunity for recovery of natural systems or communities. This poster summarises the objectives, approach and methodology for this storm surge project. A contribution to the Bushfire and Natural Hazards CRC.

Eutrophication has become a growing concern for lakes, estuaries and other coastal waters in southwestern Western Australia since about 1945 when the application of phosphatic fertilisers was increased to compensate for nutrient deficient soils (Hodgkin and Hamilton, 1993). This study reports on a number of bulk sediment parameters (e.g. TOC, TN, TP & TS, d13C, and TOC/TN, TOC/TP C/S and Mg:Fe ratios) that have been measured for a suite of estuaries from southwestern WA. The data are interpreted in terms of sources of organic matter to-, and climatic, geomorphic, anthropogenic and biotic controls on sediment concentrations of C, P and N at southwestern Australian sites. The bulk sediment characteristics of the WA estuaries are also compared to those from a large number of coastal waterways from around Australia.