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Highlights
- Large export beef cattle feedlot
- Land disposal of organic wastes
- Hydrogeological investigation, analytical and numerical
modelling
- Preparation of remediation, management and groundwater
monitoring plans.
Background
C. M. Jewell & Associates Pty Ltd was commissioned
by the operator of the feedlot to undertake a hydrogeological
study as part of the preparation of an environmental impact
statement (EIS) and environmental management plan. The feedlot
had been in operation for a number of years, with surplus
wastewater disposed of by land application. Previous feedlot
operations had resulted in some groundwater contamination
by nitrates.
Hydrogeological Environment
The feedlot is located on the lower slopes of a hill, and
is underlain by colluvial soils which inter-finger with
extensive alluvial floodplain deposits; the latter contain
aquifers of major local importance.
Scope
Following a desk study and preparation of an inception report,
and discussion with the Department of Water Resources and
the NSW Environmental Protection Authority, a field program
involving geological mapping, drilling, test pitting, geological
and geophysical logging, test pumping, sampling and laboratory
analysis was carried out.
A conceptual model outlining the hydrogeology of the site
was developed, and formed the basis of a multi-layered finite-difference
numerical model. Using this model, a system of pumping boreholes
was designed to perform two functions: to create a groundwater
capture zone that would contain existing contamination,
and act as a backup to improved point-source controls, for
prevention of future contamination. The borehole system
will also provide water to meet feedlot consumptive use
requirements, with any surplus being used for fodder irrigation.
A detailed report setting out the results, conclusions
and recommendations of the study was prepared and submitted
as part of the EIS for the extension.
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Projects
