Effects of a rapidly urbanising environment on ground water, Brisbane, Queensland, Australia

Abstract

Southeastern Queensland, centred around Brisbane, has one of the fastest growing populations in Australia and has previously relied on surface storage of water for urban purposes. The projected demands for potable water mean that various groundwater supplies may need to be maintained for future urban use. Groundwater in this area occurs in a variety of aquifer types, some limited in extent and some susceptible to effects from increasing development, as well as from natural processes. Recorded impacts on groundwater in this area are varied and include: changes in land use from agricultural to residential; rising water tables as a result of cessation of extraction for irrigation; declining water tables in areas where irrigation has increased; decreasing quality, due to the introducing of nutrients (fertilizers and sewage); occurrence of acid saline waters in coastal Holocene sediments as a result of agricultural and engineering activities; and increased numbers of private bores on some bay islands. The large-scale managed development of groundwater supplies is now underway from North Stradbroke Island (a large sand island) to augment mainland surface supplies. At this stage, restrictions on the development of groundwater do not exist in the area, with the exception of North Stradbroke Island. Localised degradation of groundwater quality is produced by such features as old landfills, petroleum storage sites, and some old industrial sites. Possibly the major long-term impact will be the cumulative effect of increasing urban activity on a region whose drainage sink is Moreton Bay.