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  • Identification of groundwater-dependent (terrestrial) vegetation, and assessment of the relative importance of different water sources to vegetation dynamics commonly involves detailed ecophysiological studies over a number of seasons or years. However, even when groundwater dependence can be quantified, results are often difficult to upscale beyond the plot scale. Consequently, quicker, more regional mapping approaches have been developed. These new approaches utilise advances in computation geoscience, and remote sensing and airborne geophysical technologies. This study, undertaken in the semi-arid Darling River Floodplain in N.S.W., Australia, combines Landsat Normalised Difference Vegetation Index (NDVI) time series data with hydrogeological, hydrogeochemical and hydrogeophysical data to assess the relative importance of hydrological processes and groundwater characteristics. The first stage in the study combined high-resolution vegetation structural mapping derived from LiDAR data (Canopy Digital Elevation Model and Foliage Projected Cover), with 23 years of Landsat time-series data. Statistical summaries of Normalised Difference Vegetation Index values were generated for each spatially continuous vegetation structural class for each Landsat scene (e.g. stand of closed forest). This has enabled long-term temporal changes in vegetation condition to be assessed against different water regimes (drought, local rainfall, river bank full, overbank flow, and lake filling), and groundwater dependent vegetation to be identified. The second stage involved integration with airborne electromagnetics (AEM), hydrogeology and hydrogeochemistry. This has shown that the deeper (>25m), semi-confined aquifer is only rarely important to vegetation dynamics, with the shallow unconfined aquifer and river lateral bank recharge zones being of greater importance.

  • Identification of groundwater-dependent terrestrial vegetation, and assessment of the relative importance of different water sources to vegetation dynamics, typically requires detailed ecophysiological studies over a number of seasons or years. However, even when groundwater dependence can be quantified, results are often difficult to upscale beyond the plot scale. Quicker, more regional approaches to mapping groundwater-dependent vegetation have consequently evolved with technological advancements in remote sensing techniques. These approaches however often fail to incorporate sub-surface hydrogeological processes in their interpretation of groundwater dependence. This study, undertaken in the semi-arid Darling River Floodplain in NSW, Australia, innovatively combines Landsat Normalised Difference Vegetation Index (NDVI) time series data with hydrogeological, hydrogeochemical and hydrogeophysical data to assess the relative importance of hydrological processes and groundwater characteristics. Central to the approach is the use of airborne electromagnetics which provides a 3-dimensional context to otherwise point-based borehole data. This approach has resulted in an improved understanding of vegetation dynamics including the spatial distribution of vegetation utilising groundwater, timing and duration of groundwater use, and response to different hydrologic regimes (e.g. rainfall, lateral bank recharge, and overbank flooding). In particular, the study has established that the deeper (>25m), semi-confined aquifer is only rarely important to vegetation dynamics, with the shallow unconfined aquifer and river flush zones being of greater importance. These findings are being used to assess the suitability of proposed groundwater-development schemes in the study area, and have implications for riparian vegetation management more broadly.

  • Floodplain vegetation can be degraded from both too much and too little water due to regulation. Over-regulation and increased use of groundwater in these landscapes can exacerbate the effects related to natural climate variability. Prolonged flooding of woody plants has been found to induce a number of physiological disturbances such as early stomatal closure and inhibition of photosynthesis. However drought conditions can also result in leaf biomass reduction and sapwood area decline. Depending on the species, different inundation and drought tolerances are observed. This paper focuses specifically on differing lake level management practices in order to assess associated environmental impacts. In western NSW, two Eucalyptus species, River Red Gum (E. camaldulensis) and Black Box (E. largiflorens) have well documented tolerances and both are located on the fringes of lakes in the Menindee Lakes Storage Water scheme. Flows to these lakes have been controlled since 1960 and lake levels monitored since 1979. Pre-regulation aerial photos indicate a significant change to the distribution of lake-floor and fringing vegetation in response to increased inundation frequency and duration. In addition, by coupling historic lake water-level data with a Landsat satellite imagery, spatial and temporal vegetation response to different water regimes has been observed. Two flood events specifically investigated are the 2010/11 and 1990 floods. Results from this analysis provide historic examples of vegetation response to lake regulation including whether recorded inundation duration and frequency resulted in positive or negative impacts, the time delay till affects become evident, duration of observed response and general recovery/reversal times. These findings can be used to inform ongoing water management decisions.

  • Identification of groundwater-dependent (terrestrial) vegetation, and assessment of the relative importance of different water sources to vegetation dynamics commonly involves detailed ecophysiological studies over a number of seasons or years. However, even when groundwater dependence can be quantified, results are often difficult to upscale beyond the plot scale. Consequently, quicker, more regional mapping approaches have been developed. These new approaches utilise advances in computation geoscience, and remote sensing and airborne geophysical technologies. The Darling River Floodplain, western New South Wales, Australia, was selected as the case study area. This semi-arid landscape is subject to long periods of drought followed by extensive flooding. Despite the episodic availability of surface water resources, two native Eucalyptus species, E. camaldulensis (River Red Gum) and E. largiflorens (Black Box) continue to survive in these conditions. Both species have recognised adaptations, include the ability to utilise groundwater resources at depth. A remote sensing methodology was developed to identify those communities potentially dependent on groundwater resources during the recent millennium drought in Australia.

  • Subtidal to intertidal deposits from Kaipara Harbour in Northland preserve a 23,000+ year incomplete sedimentary record of the transition from terrestrial to estuarine conditions in the Wairoa River arm of the harbour. Cores are used to reconstruct the depositional setting for this transition, which we interpret as a succession from dune and freshwater wetland to shallow estuarine environments. The fossil pollen record provides a proxy of Last Glacial Maximum and Late Glacial vegetation for the area. Stability of the palaeo-dune landscape during the postglacial marine transgression is interpreted on the basis of strong dominance of tall forest taxa (Dacrydium) in the pollen record and soil development in dune sands. Reworking of buried dune and wetland sediments has only reached to a depth of 1.5 m below the modern tidal flat. As such, the site provides a rare example of good preservation of Pleistocene deposits at the coast, where extensive reworking and loss of record are more typical.

  • The White Elephant 1:7,500 regolith-landform map illustrates the distribution of regolith materials and the landforms on which they occur, described using the RTMAP scheme developed by Geoscience Australia

  • The Eagles Nest Catchment 1:7,500 vegetation map illustrates the distribution of vegetation with respect to regolith materials and the landforms on which they occur, described using the RTMAP scheme developed by Geoscience Australia

  • Background Land cover is the observed physical cover on the Earth's surface including trees, shrubs, grasses, soils, exposed rocks, water bodies, plantations, crops and built structures. A consistent, Australia-wide land cover product helps understanding of how the different parts of the environment change and inter-relate. Earth observation data recorded over a period of time firstly allows the observation of the state of land cover at a specific time and secondly the way that land cover changes by comparison between times. What this product offers DEA Land Cover provides annual land cover classifications for Australia using the Food and Agriculture Organisation Land Cover Classification System taxonomy Version 2 (Di Gregorio and Jansen, 1998; 2005). DEA Land Cover divides the landscape into six base land cover types, which are then further detailed in sub-classes. The structure of base and sub-classes is as follows: - Cultivated Terrestrial Vegetation - percentage of cover - life form (herbaceous only) - Natural Terrestrial Vegetation - percentage of cover - life form (herbaceous only) - Natural Aquatic Vegetation - percentage of cover - life form (herbaceous only) - water seasonality - Artificial Surfaces - Natural Bare - percentage of bare - Aquatic - water persistence - intertidal area

  • Geoscience Australia (GA) was invited by Murray-Darling Basin Authority (MDBA) in 2010 to participate in an evaluation of the Intermap IFSAR (Interferometric Synthetic Aperture RADAR) data that was acquired as part of the Murray-Darling Basin Information Infrastructure Project Stage 1 (MDBIIP1) in 2009. This evaluation will feed into the business case for Stage 2 of the project. As part of the evaluation GA undertook the following: 1. A comparison of the IFSAR Digital Surface Model (DSM) and Digital Terrain Model (DTM) with a recent LiDAR acquisition, covering approximately 9000Km2 of the Lower Darling Region. It focused on assessment of the data over various land cover and terrain types and identified opportunities and issues with integrating IFSAR with LiDAR. 2. A comparison of the IFSAR Vegetation Canopy Surface (DSM minus DTM) with the Lower Darling LiDAR Canopy Elevation Model (CEM). 3. A comparison between currently mapped man-made and natural water bodies over the Murray-Darling Basin with the IFSAR derived products (water mask). 4. Application of the National Catchment Boundaries (NCBs) methodology to the IFSAR data and comparison with the delineated watersheds from PBS&J (Intermap's sub-contractor). This report outlines the findings of this evaluation based on the 4 items above MDBA requested.

  • The Sustainable Management of Coastal Groundwater Resources Project was co-funded by the Raising National Water Standards Program, which supports the implementation of the National Water Initiative Program. The project was led by GHD Hassall, in consultation with Kempsey Shire Council, Geoscience Australia, NSW Department of Environment, Climate Change and Water, and Ecoseal Developments Pty. Ltd. The project aimed to improve the management of groundwater in coastal dune aquifers, undertaking a case study of the Hat Head National Park region on the Mid North Coast of New South Wales. Due to increasing pressures on groundwater resources from expanding urbanisation and tourism in this region, the sustainable management of the existing groundwater resources is of vital importance. There are many potential risks associated with extraction of groundwater resources including acidification of soils, seawater intrusion and increased salinity levels, and detrimental impacts on groundwater dependent ecosystems (GDEs). This final report documents all of the work undertaken by Geoscience Australia relating to Groundwater Dependent Ecosystems, or more specifically groundwater dependent terrestrial vegetation. Groundwater dependent ecosystems (GDEs) are naturally occurring ecosystems that require access to groundwater to meet all or some of their water requirements so as to maintain their communities of plants and animals, ecological processes and ecosystems services. Often the natural water regime of GDEs will comprise one or more of groundwater, surface water and soil moisture.