Saltwater intrusion in Southern Eyre Peninsula, December 2009

Tables
Table 1. Summary of hydrogeologic units ............................................................................5
Table 2. Aquifer parameters adopted for analytical modelling .............................................. 29
Table 3. Dimensionless parameters for seawater intrusion extent in Southern
Basins .......................................................................................................................... 30
Figures
Figure 1. Regional map showing major groundwater resources on EP ..................................1
Figure 2. Southern Basins PWA, showing location of individual groundwater
basins and SA Water production bores. ..........................................................................6
Figure 3. Typical groundwater level trends in three coastal aquifers (Coffin Bay,
Uley South and Lincoln Basin) and one inland aquifer (Uley Wanilla). .............................7
Figure 4. Salinity profiles in coastal Uley South observation wells (both ~500m
inland) ............................................................................................................................9
Figure 5. Conductivity slice at -53m ADH, annotated features include resistive
basement ridges (blue) and conductive saline groundwater (pink/red) (After
Fitzpatrick et al. 2009). ................................................................................................ 11
Figure 6. Conductivity slice at -23m AHD showing potential small seawater
wedge extending inland into Uley South........................................................................ 12
Figure 7. Interpreted surface for base of Bridgewater formation; annotation
shows area below mean sea level. ............................................................................... 13
Figure 8. Two Conceptual models for seawater intrusion in Uley South Basin. .................... 16
Figure 9. Conceptual model of fresh/saline water interactions in Lincoln B Lens
(above) and Coffin Bay (below). .................................................................................... 18
Figure 10. Conceptual model for Robison Lens; pre and post pumping (Brown
and Harrington, 2003) .................................................................................................. 19
Figure 11. Diagram of parameters for analytical model of seawater intrusion ...................... 21
Figure 12. Contours of x
T
for different M and F .................................................................. 25
Figure 13. Contours of x
T
for: (a) Uley South (SE) – QL only, (b) Uley South
(SE) – QL+TS, (c) Uley South (NW), (d) Coffin Bay A lens, (e) Lincoln B
lens. ............................................................................................................................. 31
Figure 14. Evidence of seasonal saline up-coning in Lincoln B Lens. .................................. 32
Figure 15. Plot of theoretical freshwater/saltwater interface determined from (2)
for the southeast portion of Uley South, for the two conceptual models (QL
only vs. QL + TS), showing the approximate location and screened interval
of observation well SLE069. ........................................................................................ 34
Figure 16. Plot of theoretical freshwater/saltwater interface determined from (2)
for the northwest portion of Uley South assuming a continuous clay aquitard
at a depth of 15m. ........................................................................................................ 35
Figure 17. Contours of x
T
across a range of climate change scenarios for the
three aquifer conceptualisations in the Uley South basin. .............................................. 37
Figure 18. Basic assessment of steady-state seawater intrusion extent under
different increased pumping scenarios, assuming a coastline width of 5km. .................. 38
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