2.1.3.4 Gaps

Although there are many thousands of groundwater bores and a large number of groundwater observation bores in the Clarence-Moreton bioregion, there are some distinct data and knowledge gaps. The most significant gaps that could potentially influence achieving realistic simulation and modelling based analysis are:

While some areas such as the Lockyer Valley in Queensland have a very good coverage with shallow groundwater observation bores, there is a general lack of groundwater observation bores in other parts of the Clarence-Moreton bioregion – most notably in the Clarence and Richmond river basins. This lack of data in some areas impacts on the uncertainty of recharge estimation for the sedimentary bedrock units.
There is a general lack of deep groundwater observation bores, as most observation bores (and more generally the majority of all groundwater bores) are less than 100 m deep. While there are approximately 3000 bores in the bedrock aquifers, most are relatively shallow and located either in or near areas where the bedrock outcrops. However, as the Clarence‑Moreton Basin is more than 1000 m deep throughout most of the basin and more than 3000 m in some areas, the existing groundwater monitoring network is likely to capture only a small component of the hydrodynamics of the Clarence‑Moreton Basin. Critical hydraulic information including water level, hydraulic properties and water chemistry of bedrock aquifers is currently missing.
There is a general lack of nested (multi-level) bore sites throughout the Clarence‑Moreton bioregion. Although there are some nested bore sites in the Lockyer Valley, Bremer river basin and Warrill creek catchment (less than 20 in total), there are currently no multi-level monitoring sites in the Richmond or Clarence river basins. While groundwater dynamics in shallow alluvial aquifers are relatively well understood, there is very limited knowledge on characteristics such as groundwater flow direction or inter-aquifer head gradients throughout much of the bioregion.
There are significant gaps in the groundwater databases. For example, there is no ‘aquifer’ layer where the screened interval of bores are assigned to a specific aquifer in the NGIS groundwater database. More information on hydraulic and petrophysical properties of key aquifer units need to be obtained. In particular, information for the Walloon Coal Measures and overlying stratigraphic units such as the Orara and Grafton formations are required for the numerical model development to assess the impacts associated with coal seam gas development.
The hydraulic significance of faults is poorly understood due to the lack of nested (multi-level) groundwater monitoring sites. Only limited understanding exists on the role of faults as potential pathways or barriers for aquifer interconnectivity or groundwater flow to the surface. More work, such as the use of remote sensing to identify faults that penetrate to the surface, may be required in the future.

Last updated:

8 January 2018

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