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Highlights
- Stage 2 Investigation of the area north of Haslams Creek
- Stage 2 Investigation of RANAD Newington Site
- Large areas of uncontrolled landfill
- Soil and groundwater sampling, hydraulic testing
- Sediment sampling of creeks and wetlands
- Groundwater modelling
- Risk assessment
- Development of remedial strategies.
Background
The contract for the second stages of investigation
of Homebush and the RAN armaments depot at Newington was
awarded to CH2M HILL Australia in association with ICF (later
AXIS). The site had been identified as the venue for a range
of sporting facilities and the main athletes' village for
the 2000 Olympic Games.
CH2M HILL commissioned C. M. Jewell & Associates to
carry out a range of tasks related to the hydrogeological
aspects of the study, including reviews of existing data,
field program planning, hydrochemical logging and sampling,
and report writing and review.
Hydrogeological Environment
Predominantly Triassic shales (Wianamatta Group), overlying
tightly cemented sandstones (Hawkesbury Group). The shale
is deeply lateritised and locally eroded. Where exposed,
the sandstone is highly to extremely weathered. The project
area borders the tidal Parramatta River and is bounded to
the south by Haslams Creek; it incorporates a number of
ecologically significant wetland areas. Intergranular groundwater
flow occurs in the extensive fill areas, but in the underlying
shale is localised predominantly in fracture zones, as matrix
permeability is very low. Intergranular flow may occur in
highly and extremely weathered sandstones.
Contaminants
- Pesticides: organochlorine pesticides
- Hydrocarbons: tar residues including PAH & MAH
- Heavy metals: arsenic, cadmium, chromium, copper, lead,
zinc
- Others: asbestos, phenols, ammonia
Objectives and Scope
Following a review of existing data including historical
aerial photography and the results of previous investigations,
two phases of targeted sampling of soils, sediments, groundwater
and surface waters were completed. A series of groundwater
models were formulated, a full risk assessment carried out,
and remediation strategies developed.
C. M. Jewell & Associates prepared:
- a series of working papers dealing with site and regional
hydrogeology, leachate seepage, and contaminant transport
and fate;
- the health and safety plan for the fieldwork;
- the sampling and analysis plan for the first phase of
sampling;
- the QA/QC plan for the first phase of sampling;
and also:
- supervised a high-resolution magnetic (TM4) survey of
the fill areas and EO survey of sample points;
- provided an overview of both phases of drilling and
sampling;
- carried out the Phase 2 groundwater sampling;
- carried out in-situ hydrochemical borehole logging;
- provided input to and reviewed the groundwater modelling
and remediation strategies reports; and
- wrote the core of the final Site Assessment Report.
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