Groundwater

TORI ANNE VEGELIEN PHOTO
Groundwater is the water contained within rocks and sediments below the ground's surface. It comes from rainfall and other water sources seeping down through soil and rock fractures and filling up the pores between soil and sand grains. 

Groundwater moves due to gravity and eventually reaches a discharge point where it is released to a creek, lake or the sea. It supports many ecosystems such as wetlands and river base flows.

Groundwater is most commonly accessed by bores or wells for domestic and industrial purposes. Over-extraction or contamination of groundwater can have long-term impacts on the groundwater system and may reduce the volume and quality of water available for the users and ecosystems that depend on this resource. The Department of Primary Industries - Water is responsible for the management of groundwater resources in NSW. All works connected to a source of underground water and used for water supply, groundwater monitoring, dewatering, or any other purpose must be licensed by them. 

Botany Sand Beds Aquifier

The Botany Sand Beds Aquifer is a large volume of underground water present in the sandy ground surrounding Botany Bay. It is a coastal sand bed aquifer that is readily recharged by rainfall. It extends from Botany Bay northwards to Surry Hills and Centennial Park. Groundwater within the aquifer generally flows in a northeast-southwest orientation, from areas around Centennial and Moore Parks into Botany Bay and the Botany Wetlands. 

The Botany Sand Beds Aquifer has a relatively shallow water table, often less than 1-2 metres below the natural ground surface in low-lying areas with the level varying in relation to rainfall and evaporation. It has been an important groundwater resource in Sydney’s south eastern suburbs for many decades and water is still pumped from the aquifer by industry, golf courses and residents.

Contamination and Water Quality

The Botany Sand Beds aquifer is highly vulnerable to contamination due to the permeability of the sands and water table is shallow. Contamination can occur when pollutants leak from commercial and industrial sites. Botany and its surrounding suburbs have been heavily used by industry for at least 100 years. Industries have included tanneries, wool scourers, metal platers, service stations and depots, landfills and dry cleaners. A large proportion of use was before any environmental protection controls were in place and at a time it was not considered important. As a result, chemicals such as chlorinated hydrocarbons and other solvents, petroleum hydrocarbons (such as petrol and diesel), and some heavy metals (such as chromium, nickel, lead and arsenic) may have contaminated the aquifer. This is a legacy that we are working to manage.  

There are several sites in the area which are in the process of being cleaned up or have a site management plan. The NSW Environment Protection Authority (EPA) is the lead agency responsible for managing contaminated groundwater and clean-up strategies for significantly contaminated sites. A list of these sites can be found at the EPA in the Record of Notices. The Department of Primary Industries - Water assists by supplying technical information, establishing the beneficial use of aquifer systems and restricting the take of groundwater, if necessary. 

Groundwater Management in Botany Sands Aquifer

Given the history of the area, the shallow water table and highly permeable soils, a precautionary approach to managing groundwater use in the area has been taken by the Department of Primary Industries - Water to ensure public health is not put at risk from exposure to potentially contaminated groundwater.

As a number of contaminated sites in the Botany Bay area have resulted in the contamination of groundwater in the aquifer the NSW Office of Water has developed a management approach for the Botany Bay Sands Aquifier.  

Management Zones

Based on the NSW Government’s concerns about contamination in the Botany Bay Sands Aquifier Area, the area has been divided into four management zones

In Zone 2,3 and 4, all domestic groundwater use is banned and all industrial users must test their bore water annually and provide results to the NSW Office of Water.  

There is also an embargo on applications for new licence applications to extract groundwater in the Botany Sands aquifer.

Contamination at the Orica complex

Orica (formerly ICI Australia) has operated a chemicals manufacturing facility at the Botany Industrial Park since 1942. Poor environmental management and waste disposal practices up to the 1980s resulted in significant amounts of chemicals contaminating the underlying soil and groundwater. Orica is addressing and remediating these contamination legacies. The Botany Bay City Council, in conjunction with NSW Environmental Protection Authority continues to monitor the ongoing clean up of the groundwater contamination and a member of the Orica Botany Liaison Committee (OBLC).  

Information on the groundwater contamination and remediation projects occurring at Orica Botany site can be found at Orica Australia or by calling Orica's Community Hotline 1800 025 138.