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Highlights
- Stage 1: Geophysical, aerial photogrammetric, drilling
and yield testing of Great Artesian Basin sediments
- Stage 2: Intensive drilling and pumping test interpretation.
Background
Proposed expansion of the irrigated crop production
for a beef cattle feedlot on Mungeribar Station necessitated
assessment of the groundwater resources available for abstraction.
First Aquila Agribusiness and subsequently, ANZCO Foods
commissioned C. M. Jewell & Associates Pty Ltd to undertake
a series of investigations into the resource availability.
Hydrogeological Environment
Alluvium associated with the Macquarie River directly underlies
the study area, comprising unconsolidated clays, silts and
gravel. Sandstones and shales of the Great Artesian Basin
sediments underlie the alluvium. The crystalline basement
rocks of the area underlie the sediments at relatively shallow
depths of 75 to 120 metres below ground level. A lineament
recognised from aerial photography is associated with highly
variable drilling success, but yields of up to 76 litres
per second have been obtained from this zone.
Potential Adverse Effects
The aquifers contained within the Great Artesian Basin sediments
are recharged by local infiltration of excess water and
through-flow of groundwater from outcrops to the south of
the station. Abstraction of groundwater in excess of replenishment,
competitive drawdown between multiple production bores or
boundary effects may cause short or long-term decline in
aquifer pressure, affecting neighbouring bore owners.
Objectives and Scope
Initially, preliminary assessment of the resource was made
as follows:
- a detailed review of geological, hydrogeological and
water use information,
- interpretation of aerial photographic and aeromagnetic
data,
- DC resistivity soundings, and
- drilling and logging of two boreholes, followed by step-drawdown
and recovery pumping tests.
Subsequently, six deep boreholes into the Great Artesian
Basin sediments have been drilled. Further geological and
geophysical down-hole logging, pump testing of five bores
and hydraulic interpretation have completed field investigations.
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Projects
