In February 2016, AGL announced it will not proceed with the Gloucester Gas Project. AGL will commence an extensive decommissioning and rehabilitation program for its well sites and other infrastructure in the Gloucester region.
AGL understands that protecting Gloucester’s water resources is our biggest responsibility. That’s why we undertake comprehensive water research and monitoring – by our in-house expert hydrogeologists and by independent water scientists.
AGL acknowledges that both surface and groundwater resource protection is a key issue for the Gloucester community. AGL believes it is critical to protect water resources and manage produced water as part of the sustainable development of coal seam gas.
An extensive water monitoring network has been installed across the Gloucester area and as at December 2013 includes:
Groundwater investigations for the Gloucester Gas Project are well advanced. The investigation studies that are completed and ongoing comprise the following phases:
The Phase 1 desktop study is a review of existing information to develop an initial understanding of the hydrogeological characteristics of the area.
AGL has been investigating groundwater and surface water conditions within the Stage 1 Gas Field Development Area since December 2010.
The studies involve geological appraisals, drilling, permeability testing, water level monitoring, water quality sampling, isotope studies, data collation, analysis and reporting.
In addition, the study was designed to help AGL and the community better understand the groundwater in the project area and what affects, if any, there might be on the groundwater from natural gas exploration.
Now that AGL has more than three years of water monitoring data, and has completed more Stage 1 and basinwide investigations, numerical modelling of the Gloucester Gas Project has commenced.
Numerical modelling is converting the current conceptual groundwater flow model into two and three dimensional representations of the geology and hydrogeology. Modelling allows the drawdown effects of different wellfield layouts and different development scenarios to be predicted. Likely water production volumes can be estimated together with the refinement of the current water balance for the Gloucester Basin.
These studies will help AGL with its water production estimates, and allow the community to better understand what affects, if any, there might be on groundwater and surface water resources from the Stage 1 field development.
AGL's water monitoring program describes the water level and water quality results from its extensive monitoring network. The basin-wide monitoring network is shown here. Interpreted monitoring reports are released annually around September each year for the previous water year.
The hydrogeological studies conducted to date have shown that there is no evidence of natural connectivity between shallow and deep groundwater systems.
AGL has commenced additional investigations that expand on our detailed groundwater investigations and monitoring programs. Read the reports under Water Reports in the document library.
AGL Upstream Gas, as part of its CSG exploration and production programs in NSW and QLD, commissioned a desktop study on the occurrence of naturally occurring hydrocarbons in groundwater from Permian coals measures and associated sedimentary rocks. The report prepared by CSIRO and Earth Science and Resource Engineering - Petroleum and Geothermal Research Portfolio Group concluded that most of the detected total petroleum hydrocarbons, PAH (polycyclic aromatic hydrocarbons) and BTEX (benzene, toluene, ethyl benzene and xylenes) compounds appear to be naturally occurring.
AGL is required to hold bore licences from the NSW Office of Water for its exploration and groundwater monitoring activities that involve drilling and taking groundwater from bores/wells or monitoring groundwater associated with the local groundwater systems of the Gloucester Basin. The following are typical of the 40+ bore licences that AGL holds for the current CSG exploration activities:
AGL recognises that independent scientific water studies have a major role in the management and regulation of the coal seam gas industry. That’s why we developed a cooperation agreement with Gloucester Council. Council will deliver a number of important studies relating to flooding, produced water and property (water surveys). Council will also be commissioning independent peer reviews of important AGL water studies. To assist Council in this task, AGL is funding a full time water scientist position.
AGL believes this independent scientific support will build understanding of coal seam gas activities in the Gloucester community.
When it rains, the majority of water runs over the surface of the land and a small amount seeps underground where a proportion is used by native vegetation, pastures and crops. A smaller amount of water penetrates to the water table beneath the floodplain, which is relatively shallow with alluvial sands and gravels containing mostly good to brackish quality water.
On the valley sides, over thousands of years, a very small amount of shallow groundwater seeps through the underlying rock, to replenish deep groundwater in the deeper rocks. This water is very old and can be brackish and slightly salty as it contains minerals from the rocks it has travelled through.
Beneficial aquifers mostly occur within 75 metres of the surface, but because Gloucester is located in a high rainfall area, there is little use of these groundwater resources.
Similar to a drinking straw, a monitoring bore lets us find out what is happening with groundwater. We drill a hole into the ground and install a sealed pipe that has tiny holes at the bottom to let groundwater enter the pipe. The groundwater rises up the pipe to a water level that reflects the water pressure in that aquifer where the bore is installed.
We often put several monitoring bores next to each other, installed to various depths, to monitor groundwater in different aquifers or groundwater systems. We can then measure the water level and water quality in each of the bores to see how they relate to each other and how they change over time.
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