Hurstville City encompasses parts of the Georges River and Cooks River catchments. A ‘catchment’ is an area of land that collects surface water which then drains to a common river or major body of water such as a bay. Each catchment is separated by hills or ridges which direct the surface water into creeks, drains and channels. Everything that happens in a catchment is linked. For instance, a pollution incident in the upper part of a catchment can have a harmful impact on water quality and aquatic plants and animals further downstream.
In urbanised catchments like Hurstville City, there are many impervious surfaces such as concrete, roads, driveways, roofs that cause rainfall that would previously have entered the soil or flowed off catchments at a slow rate, to flow off the catchment quickly and in greater volumes, transporting pollutants into waterways.
Georges River Catchment
The Georges River is one of Hurstville’s primary natural assets due to its aesthetic, recreational and biological value. The Georges River rises five kilometres south-east of Appin, near Campbelltown at a height of 350 metres. The river winds its way 96 kilometres to Botany Bay. It is divided into three main regions: the upper (freshwater section from Appin to Liverpool Weir), middle reaches (Liverpool Weir to Salt Pan Creek) and lower (Salt Pan Creek to Botany Bay).
The Georges River catchment is very large and covers an area of 960 square kilometres. It is highly urbanised and supports a wide range of land use, including an Australian Army firing range, market gardens, agriculture, mining, industrial manufacturing, landfill, and a nuclear research facility. Large bushland areas, including remnant floodplain forests of the Cumberland Plain and riparian areas still remain.
Some of Sydney’s older suburbs such as Rockdale and Hurstville are in the catchment, as well as some of its newest housing estates in the area of Liverpool and Fairfield. Around 1.2 million people live in this south-western Sydney catchment.
Hurstville City is situated on the foreshores of the lower Georges River, and Salt Pan Creek forms a natural boundary to the west. Salt Pan Creek is a major tributary of the Georges River and covers a total catchment area of 26 square kilometres, of which 5.2 square kilometres is in Hurstville. It drains the suburbs of Riverwood, and parts of Peakhurst and Lugarno. The sub-catchment is dominated by residential properties with small areas of foreshore and parkland including the CF Williams Reserve and Georges River National Park. There are three commercial shopping strips which include Riverwood, Lugarno and Peakhurst.
There are three sub-catchments within Hurstville City's lower Georges River catchment area:
Lime Kiln Bay
Lime Kiln Bay is Hurstville City's largest sub-catchment of the Lower Georges River. Stormwater discharges into Lime Kiln Bay from a gully originating in Mortdale as well as a large basin which discharges at the downstream end of the Hurstville Golf Course. Boggywell Creek also discharges directly into the Lime Kiln Bay.
Landuse is divided fairly equally between residential housing, open space/parks reserves and industrial areas. Open space/park reserves line the main drainage tributaries entering Lime Kiln Bay including Gannons Park which runs along the length of Boggywell Creek; Oatley Heights Park and Oatley Park. The Hurstville Golf Course is located above the northern tip of Lime Kiln Bay. North of the Golf Course is the Peakhurst Industrial Area which includes a range of businesses from smash repairers to furniture manufacturers.
Jewfish Bay/Gungah Bay
The landuse surrounding Jew Fish Bay is mostly open space/reserve, while residential properties dominate the landscape fronting onto Gungah Bay. Oatley Park forms the large portion of open space located directly on Jew Fish Bay, through which several stormwater drains pass through and discharge into the Jew Fish Bay.
A minor creek tributary entering Gungah Bay is flanked by park reserve along the Illawarra Railway Line. Oatley shopping strip drains to Gungah Bay.
Edith Bay is a small sub-catchment of Lugarno. A minor tributary enters the bay through Edith Bay Reserve. The landuse surrounding Edith Bay is mostly residential. The foreshore area is being upgraded with a new wetland and boardwalk.
Cooks River Catchment
Some stormwater from the local government area of Hurstville flows into the Cooks River via piped drainage systems. Hurstville’s part of the Cooks River catchment takes up approximately 9.1 per cent.
The Cooks River originates in Bankstown and flows 23 kilometres east to discharge into Botany Bay just south of Sydney airport. The catchment area covers an area of 100 square kilometres and is highly developed. The catchment provides a home to over 400,000 people and has a variety of land uses, ranging from industrial to open space. Little remains of the original landscape and vegetation, even though the river is flanked by parkland and open space for most of its length.
The major tributaries of the Cooks River are Wolli Creek and Bardwell Creeks, Muddy Creek, Alexandra Canal and Sheas Creek, Cup and Saucer Creek, Cox’s Creek and Freshwater Creek. There are two sub-catchments within Hurstville’s Cooks River catchment area.
Wolli Creek is the second biggest sub-catchment of the Cooks River, covering a total area of 15.52 square kilometres. Wolli Creek begins as a watercourse in Beverly Hills adjacent to Canterbury Golf Course. In Hurstville’s area of the catchment, Wolli Creek drains the suburbs of Beverly Hills, Kingsgrove and Hurstville, before flowing through suburbs of Rockdale.
Wolli Creek is a lined channel downstream of Kingsgrove Road to Bexley Road. Thereafter the lower reaches of the creek to the Cooks River is largely in a ‘natural’ state forming a winding watercourse through the Wolli Valley. The landuse is primarily residential, with small light industrial areas including the Kingsgrove Industrial Estate.
Bardwell Creek is the major tributary of Wolli Creek and has a total catchment area of 6.36 square kilometres. The upper reaches of Bardwell Creek rise in Hurstville and drains the suburb of Hurstville, before flowing in a north-easterly direction into the local government area of Rockdale, which encompasses the large majority of the catchment. The upper reaches of the Creek are a piped drainage system, which becomes an open concrete channel at Croydon Road in the Bexley Golf Course.