The OzCoasts web-based database and information system draws together a diverse range of data and information on Australia's coasts and its estuaries. Maps, images, reports and data can be downloaded and there are tools to assist with coastal science, monitoring, management and policy. The content is arranged into seven inter-linked modules: Search Data, Conceptual Models, Coastal Indicators, Habitat Mapping, Natural Resource Management, Landform and Stability Maps and Climate Change. The Climate Change module is the newest feature of the website and was developed in partnership with the Australian Government Department of Climate Change and Energy Efficiency. The module provides information and tools to help communicate the risks of sea-level rise and other potential impacts of climate change on coastal areas. It includes an elevation data and a modelling portal for access to existing and new elevation data and derived products, including sea level inundation maps for Perth to Mandurah, Melbourne, Sydney, Hunter and Central Coast & Brisbane and Gold Coast. The inundation footprints illustrate three sea level rise scenarios: a low (0.5m), medium (0.8m) and high (1.1m) scenario for a 2100 time period, with values based on IPCC projections (B1 and A1FI scenarios) and more recent science. OzCoasts will also soon deliver the Coastal Eutrophication Risk Assessment Tool (CERAT) for the NSW Department of Environment, Climate Change and Water, and the Australian Riverscape Classification Service (AURICL) for the Tropical Rivers and Coastal Knowledge (TRaCK) consortium. CERAT will help identify and prioritise land use planning decisions to protect and preserve the health of NSW estuaries. AURICL has a northern tropical focus, and is a dynamic and flexible system for classifying catchments and their rivers based on the similarity, or dissimilarity, of a wide range of parameters.

Legacy product - no abstract available

Note that this Record has now been published as Record 2014/050, GeoCat number 78802

No abstract available

In this paper a new benchmark for tsunami model validation is pro- posed. The benchmark is based upon the 2004 Indian Ocean tsunami, which provides a uniquely large amount of observational data for model comparison. Unlike the small number of existing benchmarks, the pro- posed test validates all three stages of tsunami evolution - generation, propagation and inundation. Specifically we use geodetic measurements of the Sumatra{Andaman earthquake to validate the tsunami source, al- timetry data from the jason satellite to test open ocean propagation, eye-witness accounts to assess near shore propagation and a detailed inundation survey of Patong Bay, Thailand to compare model and observed inundation. Furthermore we utilise this benchmark to further validate the hydrodynamic modelling tool anuga which is used to simulate the tsunami inundation. Important buildings and other structures were incorporated into the underlying computational mesh and shown to have a large inuence of inundation extent. Sensitivity analysis also showed that the model predictions are comparatively insensitive to large changes in friction and small perturbations in wave weight at the 100 m depth contour.

Geoscience Australia's Risk Research Group is using a variety of GIS coverages that span the Fremantle to Hillarys region of the Perth coastal system to assess the vulnerability of the Perth built environment to the potential impact of coastal erosion. Two fundamental questions are asked: whether there is accommodation space in the system that has the potential to act as a sink for eroded sediment, with or without a future sea level rise, and; whether the three-dimensional architecture of the shoreline facies precludes erosion given the current wave and storm climate. Morphological evidence suggest the Garden Island Ridge, up to and including Rottnest Island, has sheltered the coast from prevailing longshore currents. Little sedimentation has occurred in this sector, and consequently there is accommodation space for eroded sediment to be deposited below a level at which it has the capacity to be reworked onto the beach by fair-weather beach building processes. The shoreline geology of the Perth region is dominated by sand and limestone. Shear wave velocities measured through seismic cone penetrometer testing are used in conjunction with natural periods of vibration for the coastal sands to reconstruct the three-dimensional distribution of the erosion-resistant limestone. This reconstruction shows that the upper surface of the limestone is generally above sea level, suggesting the majority of the Perth coastal region is not at risk of significant erosion. At a number of localities, however, the contact between the limestone and the overlying sand is below sea level. These areas are prone to erosion resulting in significant risk to urban development.

Measurements of benthic nutrient recycling rates were made at various sites throughout Moreton Bay in February, 1998. Benthic flux chambers were used to define solute exchange rates between the sediments and overlying water column for oxygen (-14 -87 mmol m-2d-1), ammonia (-0.1 - 3.8 mmol m-2d-1), nitrate (-0.1 - 2.1 mmol m-2d-1), phosphate (0.04 - 0.57 mmol m-2d-1), silicic acid (1.0 - 12 mmol m-2d-1), total alkalinity (-44 - 60 meq m-2d-1), TCO2 (26 - 204 mmol m-2d-1), and radon 222 (70 - 490 atoms m-2s-1). Organic carbon oxidation rates were highest in mangrove sediments (~ 200 mmol m-2d-1), were lower within sandy/seagrass sediments (~60 mmol m-2d-1) and generally higher than those measured in muddy sediments (~35 mmol m-2d-1). Diatomaceous phytoplankton debris - partly derived from sewage nutrient inputs - accounts for a large portion of the organic matter diagenesis taking place in the muddy sediments and also to lesser extents in mangrove and sandy/seagrass sediments. Diatoms (because they are heavy and sink) are an important vector, particularly in the muddy sediments, to transport N and P to sedimentary sites of denitrification and P-sequestration. The degree to which muddy sediments return ammonia to the overlying water column is highly dependent on the oxygen concentration of the overlying water. This may reflect a critical instability in the diagenetic/microbiological capacity of muddy sediments to nitrify and denitrify and could result in a positive feedback to increase eutrophication. High denitrification efficiencies were found in the sandy sediments of eastern MB. Naturally occurring radon and introduced tracer Br indicate that bio-irrigation must play an important role in the exchange of solutes across the sediment-water interface.

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

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....

Benthic nutrient fluxes from the sediments were measured at three Sites in the Bombah Broadwater of Myall Lakes during the winter (June) of 2000. Surface sediments (0-1 cm) and two cores were collected at each site and processed for measurements of carbon and nitrogen isotopic composition of the OM (organic matter), biomarkers and bulk sediment composition (OM and major cations). Pore waters were extracted from sediments and measured for both organic and inorganic metabolites. Biomarker, benthic flux data and the compositions of inorganic metabolites in pore waters indicated that Redfield OM (organic matter) was predominant in the sediments and mostly diatomaceous and probably responsible for the observed release of nutrients from the sediments to t he overlying waters. Carbon degradation rates in the sediments, during these winter month, varied between 5-47 mmol m-2 d-1 (60-564 µg m-2d-1) and were highest in the muddy sediments (mean = 21.3 +/-12.7 mmol m-2 d-1) as compared to the sandy sediments (mean = 11.6 +/-4.8 mmol m-2 d-1). DIN fluxes were less than those predicted from CO2 fluxes and Redfield stoichiometry and the `missing nitrogen' (subsequently determined by mass spectrometry as N2) was indicative of denitrification in the surface sediments. Rates of denitrification calculated from N2 directly and from `missing N' were similar and up to 5.1 mmol N m-2 d-1. There was no evidence of organic metabolite fluxes although the organic and inorganic metabolite concentrations were similar in the pore waters. Denitrification efficiencies were high (mean = 80 +/- 4%) in the sandy sediments and lower (although there was considerable variability) in the muddy sediments (mean =38% +/- 9%). Most DIP (generally > 70%) liberated to pore waters during OM degradation was not released into overlying waters but remained trapped and enriched in surface sediments. Benthic nutrient fluxes (average DIN/DIP = 131) were preferentially enriched in N compared to the OM (N/P = 16) raining into the sediments. Adjective biophysical processes (not diffusive) dominated the fluxes of metabolites across the sediment -water interface.