Biodiversity Strategy - Gosford City Council - NSW Government

A - 6.0 AQUATIC BIODIVERSITY
This section describes aquatic habitats in the Gosford Local Government Area. It collates
information from a variety of documents and reports prepared to address coastal
resource management, locally and regionally. It highlights important gaps in our
knowledge of local aquatic biodiversity and processes that impact it.
Key points
• Estuarine ecosystems contain critical habitats that require greater conservation
effort.
• There is little information available about the marine environments.
• The coastal lagoons are suffering from urban development, which needs to be
addressed with a review of management practices.
• The major tributary creeks of Brisbane Water are polluted.
• Smaller creeks are choking up with weeds and sediments.
A - 6.1
Introduction
Within the Gosford City Council local government area there is an incredible diversity of aquatic habitats.
The area includes freshwater and marine wetlands, rivers, creeks, estuaries, lagoons, beaches, coastal
reefs and rock platforms (Figure 6.1). The majority of these habitats are in relatively good condition and
support a healthy diversity of aquatic flora and fauna. Other habitats, such as urban streams and
particularly the coastal lagoons, are under huge presure from development.
The Gosford LGA is located within the Hawkesbury Shelf Marine Bioregion, which extends
south from the Hunter River at Newcastle to Shellharbour. This bioregion is one of 65 marine
bioregions that cover the Australian coast (Breen et al. 2005). Brisbane Water and the
Hawkesbury River are of particular importance because of their extensive stands of mangroves
and saltmarsh, which are the second largest, within this bioregion, after Port Stephens.
Brisbane Water is the major feature of the area with Gosford situated on the northern shore.
This waterway includes many bays, islands and the large Kincumber Broadwater to the east. It
has a fairly narrow and restricted channel to Broken Bay which provides limited tidal flushing.
The Hawkesbury River meets Broken Bay near Lion Island and Mangrove, Popran, Mooney
Mooney, Mullet and Patonga Creeks all flow into it. Coastal estuaries (or intermittently closed
and open lakes and lagoons (ICOLLS)) are found at Wamberal, Terrigal, Bulbararing Lagoon
and Avoca Lake and Cockrone Lagoon. These have restricted sea connection and would
naturally, over considerable time, close completely.
Major coastal creeks are Narara, Erina, Nunns, Egan, Kincumber, Saltwater, Cockrone and
Kahibah Creeks. There are also some freshwater lagoons remaining, most notably the Lisarow
Wetlands, Everglades Wetland and Illuka Lagoons on the Umina Sandplain. All have been
modified and impacted by surrounding developments that has altered their natural hydrological
regimes. More extensive freshwater wetlands would once have existed on much of the low lying
areas of the eastern parts of the LGA.
Rocky reefs and rock platforms occur along the coast and beaches stretch from Patonga, along
the edges of Broken Bay to Forrester's Beach in the north.
Biodiversity - Technical Report Page 129