Recharge systems for protecting and enhancing groundwate

TOPIC 7
Water re-use for agriculture / Sustainability of managing recharge systems 861
CONCLUSIONS
The use of infiltration basins on Bribie Island has successfully protected the aquifer against seawater intrusion
despite significant lowering of the water table adjacent to water extraction trench. Modeling has been able to successfully
indicate groundwater levels in the recharge area and predict flow paths for the recharge plume. The model
has been useful in investigating localised effects of aquifer recharge and establishing an effective monitoring program.
The monitoring program has confirmed movement of recharge water towards the potable water extraction
area but indicates that recharge water is a minor component of groundwater in the vicinity of the extraction trench.
Nitrogen levels in groundwater are variable with a general increase at the southern boundary compared to background
but no clear trends north of the recharge area and no increase near the potable water extraction trench.
Groundwater phosphorus and bacteria are not significantly affected by recharge. Groundwater pH across the aquifer
is affected by a number of factors with the effect of recharge being minor. There appears to be no serious environmental
or health related impact resulting from the use of reclaimed water for aquifer recharge at Bribie Island.
REFERENCES
Isaacs L.T., Walker F.D. (1983). Groundwater Model for an Island Aquifer: Bribie Island Groundwater Study,
Research report CE44, Dept of Civil Engineering, Queensland University, Brisbane, Australia.
John Wilson and Partners (1996). Bribie Island Sewage Treatment Plant: Report on Groundwater Modeling and
Monitoring, Report to Caboolture Shire Council, Queensland, Australia.
John Wilson and Partners (2000). Bribie Island Groundwater Investigations, Report to Caboolture Shire Council,
Queensland, Australia.
10 – 16 June 2005, Berlin ■ 5th International Symposium ■ AQUIFER RECHARGE ■ ISMAR 2005