coast
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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.
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This map shows the area of the Kuuku Ya'u Native Title Claim, which extends approximately between Olive River and Nyllichi Point in Cape York Peninsula, Queensland. The map was produced for the Attorney-General's Department. Not for public distribution.
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The variability in the inherent optical properties along an estuary-coast-ocean continuum in tropical Australia has been studied. The study area, the Fitzroy Estuary and Keppel Bay system, is a shallow coastal environment (depth < 30 m) with highly turbid waters in the estuary and blue oceanic waters in the bay and subject to macrotides. Biogeochemical and inherent optical properties (IOPs) were sampled in the near-surface layer spatially and across the tidal phase during the dry season. These determinations included continuous measurements of spectral absorption, scattering and backscattering coefficients, together with discrete measurements of spectral absorption coefficients of phytoplankton, nonalgal particles and colored dissolved organic matter, and concentrations of phytoplankton pigments and suspended matter. Because of a large variability in the characteristics of the water components on short spatial and temporal scales, we observe a large variability in the associated optical properties. From the estuary to the bay, particle scattering and dissolved absorption decreased by 2 orders of magnitude, and nonalgal particle absorption decreased by 3 orders of magnitude. We also observed a strong variability in particle single scattering albedo and backscattering efficiency (by a factor of 6) and in specific IOPs (IOPs normalized by the relevant constituent concentration) such as suspended matter-specific particle scattering and chlorophyll-specific phytoplankton absorption. Superimposed on this strong spatial variability is the effect of the semidiurnal tide, which affects the spatial distribution of all measured properties. These results emphasize the need for spatially and temporally adjusted algorithms for remote sensing in complex coastal systems.
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Freshwater coastal aquifers provide an important resource for irrigated agriculture, human consumption and the natural environment. Approximately 18 million people live within 50 km of the coast in Australia, and many coastal communities are reliant on groundwater. These coastal aquifers are vulnerable to seawater intrusion (SWI) - the landward encroachment of seawater - due to their close proximity to the ocean. To assess the threat of SWI in Australia, a comprehensive literature review was undertaken with input from state/territory agencies. The literature review, in combination with contributions from stakeholders, identified sites within each of the states and the Northern Territory where SWI had been reported or where it was considered to be a serious threat. International Association of Hydrogeologists 2013 Congress poster
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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.
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Objectives 1. To determine the horizontal and vertical extent of hydrogen sulphide (H2S) in Lake Wollumboola sediments. 2. To examine controls on H2S gas production in Lake Wollumboola sediments. Activities 1. During a visit to Lake Wollumboola in November 2001, Geoscience Australia collected sediment samples, from sediment cores to depths of generally 180 mm, and occasionally to 600 mm. 2. The 12 sample sites chosen incorporate the three different sediment types of Lake Wollumboola; marine sands on the eastern side of the lake, central basin muds in the relatively deeper central part of the lake, and fluvial sands and muds on the western side of the lake where the creeks are depositing sediment from the catchment. 3. We measured H2S in sediment porewaters, immediately after sample collection. Porewater sulphate and chloride were measured in the laboratory. 4. Total sulphur, total iron, and total organic carbon were measured in the laboratories at Geoscience Australia, after the survey. Background Bacteria, which occur naturally in Lake Wollumboola's sediments, produce H2S when they breakdown organic matter. The bacteria, which are called sulphate reducing bacteria, utilise sulfate from the water to breakdown the organic matter, and can only operate under oxygen free (anoxic) conditions. Key Findings 1. H2S production in Lake Wollumboola is extensive. The average H2S concentration in the central basin muds and fluvial sands and muds is ~3000 M. At one site in the central basin muds, H2S concentration is greater than 10 000 M. In contrast, the concentration of H2S in the sandy marine sediments on the eastern side of the lake is low in comparison to the central basin muds and fluvial delta sands and muds. The average H2S concentration in the marine sands is 158 M. 2 Measurements of total organic carbon show that the amount of organic matter is higher in the central basin muds and fluvial delta sands and muds (~3.5 wt%) than in the marine sands (~0.8 wt%). Organic matter is the fuel for H2S production. High H2S concentrations in the central basin muds and fluvial delta sands and muds are probably a result of their high organic matter contents. 3. Depth profiles of H2S concentration and sulphate depletion in the central basin muds and fluvial sands and muds show that H2S production is occurring right at the sediment surface and down to depths of 80-100 mm. This implies that H2S could escape directly into the atmosphere, when the central basin muds and fluvial sands and muds are exposed during times of low lake levels. It also suggests that H2S could build up in the bottom layer of water directly above these sediments if the water remains anoxic for periods of time. 4. Total sulphide measurements show that H2S is reacting with iron in the sediments, forming iron sulphide minerals. Iron is an important trapping mechanism for H2S, preventing its escape to the atmosphere. Most sites, however, do not have enough `reactive iron' available and H2S concentrations are able to build-up in the porewaters of the sediment.
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Results are given of investigations carried out to detect any variation in the relative proportions of the several heavy minerals in heavy concentrates separated out from beach sands of the Broadbeach Recreational Area. The possible variation of the thoria content of monazite in the area is also investigated. Results indicate a systematic variation from east to west in the proportion of Zircon, rutile and ilmenite in the concentrates. The thoria content of the monazite in the area is shown to be constant within experimental limits.
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Geoscience Australia conducted a survey to measure the benthic nutrient fluxes in Wallis Lake, during February 2003. The objectives were to: 1. measure the nutrient (and other metabolite) fluxes across the sediment-water interface at sites in Pipers Creek, Muddy Creek, Wallis Creek and in the Central Basin of Wallis Lake; 2. describe key processes controlling the nutrient fluxes across the sediment-water interface at each of the four sites; and 3. determine the trophic state and assess the estuarine condition of the four selected sites in Wallis Lake. The results of this recent summertime survey were compared to the observations made during the winter survey conducted in June, 2000. Pipers Creek and muddy Creek were similar in that they were both poorly flushed and close to nutrient discharges. These sites are at risk of experiencing eutrophic conditions. Wallis Creek had a high carbon loading, however the presence of seagrass and high denitrification efficiencies means this site remains in a 'good condition. Similarly, the Central Basin remains in a 'good' condition despite an increase in the carbon loading between winter and summer.
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This study examined the geomorphology of the sea bed, the spatial distribution of the various sediment types and the geomorphic evolution of Cockburn Sound.
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Geoscience Australia is the national custodian for coastal geoscientific data and information. The organisation developed the OzCoasts web-based database and information system to draw together a diverse range of data and information on Australia's coasts and its estuaries. Previously known as OzEstuaries, the website was designed with input from over 100 scientists and resource managers from more than 50 organisations including government, universities and the National Estuaries Network. The former Coastal CRC and National Land and Water Resources Audit were instrumental in coordinating communication between the different agencies. Each month approximately 20,000 unique visitors from more than 140 countries visit the website to view around 80,000 pages. Maps, images, reports and data can be downloaded to assist with coastal science, monitoring and management. The content is arranged into six inter-linked modules: Search Data, Conceptual Models, Coastal Indicators, Habitat Mapping, Natural Resource Management, Landform and Stability Maps. More....