The Groundwater and Storage interactions project arose out of a meeting on the shoulder of the Greenhouse Gas Technologies Conference in Amsterdam in 2010. It was decided to concentrate initially on the Australian Flagships projects. On 3 May 2011 Australian researchers and government agencies met and presented their work to date. In these slides COLLIE HUB, Western Australia, present on potential issues related to regional groundwater resources

1. The Collie Hub project
Potential issues related to
regional groundwater
resources
Philip Denby

2. Regional groundwater
resources
• Approximately 60-80% of water usage in south-west
Western Australia sourced from groundwater
• Mediterranean climate in south-west WA (hot, dry
summers and mild, wet winters
• Research predicts drying climate over next 50 years =
increasing pressure on groundwater resources
• Abstraction for public water supply in Perth from
groundwater: 45 GL/a in 1996/7 to 120 GL/a in 2009/10.
Likely to increase to 165 GL/a for 2010/11.
• Proposed GSWA Harvey 1 located 115 km south of Perth

3. Regional geological setting
• Groundwater resources
PERTH
derived primarily from the
Perth Basin, a sedimentary
sequence up to ~12 km thick
• Perth Basin hosts units from
Permian to Quaternary age
• Superficial, Leederville and
Yarragadee Formations form
significant regional aquifers
• Industrial use of groundwater
from Cattamarra Formation
= GSWA Harvey 1
Figure source: Iasky and Lockwood, 2004,
GSWA. Record 2004/8

4. Local geological setting
(<1000 m depth)

5. Major aquifers in the
study region
Superficial aquifer
• Largely unlicensed use for domestic or agricultural use
• Groundwater salinity varies from fresh to saline. The aquifer
becomes less permeable to the east, near the Darling Scarp
Leederville aquifer
• Up to 200 m thick in the study area
• Salinity increase to 2,500 mg/L TDS at base of formation
Cattamarra Formation (Yarragadee aquifer)
• Licensed use limited to industrial operations 40 km to north-east
of study area
• Groundwater near Harvey Line: high salinity >30,000 mg/L TDS
below 500 m depth, though little data below 800 m bgl

6. Yarragadee aquifer
• Upper Jurassic fluvial
sandstone (up to 3 km
thick)
• Sands typically comprise
80-95% of the formation
• Significant abstractions
where present in Perth
Basin
• Absent in proposed
Collie Hub project
location

7. Groundwater monitoring
• Network of DoW
monitoring bores across
the Perth Basin
• Data used to map aquifer
characteristics and used
for groundwater
modelling
• Targeted program in
place to improve
monitoring network
across the state
= GSWA Harvey 1

8. Improvements in understanding
of regional hydrogeology
• Increasing use of 3D
modelling to improve
conceptual understanding
of geology/hydrogeology
• Increasing use of
automation (e.g. data
loggers for higher frequency
of records)
• Ongoing investigation target
knowledge gaps (e.g.
Murray-Peel investigation) Distribution of sub-units of the
Yarragadee Formation in the
southern Perth Basin

9. Modelling in Petrel giving new insights into understanding geology
and hydrogeology of the Perth Basin

10. Groundwater investigations in
the study region
• Additional monitoring bores
shall be installed north of the
proposed investigation site
• Part of the Department of
Water’s State Groundwater
Investigation Program (SGIP)
• Investigation will target the
Leederville and Cattamarra
aquifers (start mid-2011) to
improve monitoring coverage
and feed into allocation plans

11. What are some of the DoW’s
concerns about CCS?
• Lack of significant hydrogeological data in the study area
(e.g. groundwater quality in the ‘target’ formations)
• What is the potential impact of CO2 injection on existing
groundwater quality and formation geochemistry?
• Structural geology needs better definition – will this have
any impact on CO2 migration?
• Are shallow (i.e. <1000 m deep) groundwater resources
in the region at risk of contamination from vertical
migration of CO2 ?
• Will potentially useable sources of groundwater above
the injection point be isolated?