Under the Community Stream Sampling and Salinity Mapping Project, the Australian Government through the Department of Agriculture, Fisheries and Forestry and the Department of Environment and Heritage, acting through Bureau of Rural Sciences, funded an airborne electromagnetic (AEM) survey to provide information in relation to land use questions in selected areas along the River Murray Corridor (RMC). The proposed study areas and major land use issues were identified by the RMC Reference Group at its inception meeting on 26th July, 2006. This report has been prepared to facilitate recommendations on the Barr Creek - Gunbower study area. The work was developed in consultation with the RMC Technical Working Group (TWG) to provide a basis for the RMC Reference Group and other stake holders to understand the value and application of AEM data to the study area. This understanding, combined with the Reference Groups assessment of the final results and taking in account policy and land management issues, will enable the Reference Group to make recommendations to the Australian Government.

Legacy product - no abstract available

Legacy product - no abstract available

In this study, 3D mapping using airborne electromagnetics (AEM) was used to site a monitoring bore network in the Darling River floodplain corridor. Pressure loggers were installed in over 40 bores to monitor groundwater levels primarily in the shallow unconfined Coonambidgal Formation aquifer, deeper (semi)confined Calivil Formation and confined Renmark Group aquifers. In 2010-11, the network provided the opportunity to monitor the groundwater response to flooding of the Darling River and the replenishment of the Menindee Lakes storages, following a period of prolonged drought. In this event, the Darling River at Menindee (Weir 32) rose from 1.59m in October 2010 and peaked at 7.16m in March 2011. A synchronous rise in groundwater levels varying between 0.5-3.4m was observed in the shallow unconfined aquifer near the river. Shallow groundwater levels also declined following the flood peak. Near-river groundwater levels in the Calivil aquifer rose between 0.2-1.3m and also by 4.0 m at a site near Lake Menindee. The latter confirms lake leakage into the aquifer at this particular site, as previously inferred by the AEM data. There was also a pressure response of 0.1-0.9m evident in certain Renmark aquifer bores near the river. The monitoring confirms the importance of episodic flood events to the recharge of the alluvial aquifers, as supported by groundwater chemistry and stable isotope data. Although some of the confined aquifer response may relate to transient hydraulic loading associated with the flood, the inference is that in places there is a degree of hydraulic connectivity between the aquifers.

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

One of the primary requirements of managing our water resources sustainably is an understanding of the water balance. Key components of a water balance model are inputs of recharge and outputs or discharge. Rates of recharge and discharge change in response to climate, landscape morphology, geology, soil/regolith, native vegetation and landuse (including landuse history). The variable nature of these parameters results in a high degree of local variability when determining recharge and discharge fluxes both spatially and temporally. Water managers deal with this complexity in a variety of ways. Where detailed information on key parameters influencing recharge and discharge are available, comprehensive, fully distributed groundwater models are used. However, in most cases this information is not available (e.g. data poor areas) and typically a crude estimation of recharge (2-10% of average annual rainfall) is given. In these cases, discharge is often assumed to be zero. A collaborative project, funded by NWC and involving CSIRO Land and Water and Geoscience Australia, has developed a new national framework for estimating recharge and discharge in data poor areas. The approach consists of excel-based models that allow the user to populate key input fields (e.g. rainfall, soil and regolith texture, bedrock type, vegetation) to generate estimates of recharge and discharge. These excel models have been coupled with a complementary national-scale GIS dataset to assist the user in populating model input fields. In combination, the models and the GIS datasets allow the user to rapidly estimate recharge and/or discharge anywhere in Australia. The national-scale GIS datasets are available through a WEB-based interface. This presentation will focus on the development of the input datasets and will provide a brief demonstration of the WEB-based interface.

Legacy product - no abstract available

Legacy product - no abstract available