The coastal environment

The urban area of Sutherland Shire is surrounded by coastal waters, including Bate Bay, Botany Bay, the Georges River estuaries, Port Hacking and Woronora River.

NSW coastal management framework

The NSW Government's coastal management framework aims to achieve a healthy and resilient coastline.

The framework is implemented through Coastal Management Programs (CMPs), which are prepared by local councils and set long-term, coordinated and sustainable management directions.

Figure 15 Staged approach to Coastal Management Programs

Sutherland Shire has three CMPs:

  • Bate Bay CMP: Stage 4 has been completed. Stage 5 includes beach nourishment, the upgrade of the Esplanade between Cronulla and North Cronulla beaches and the construction of a seawall at Dunningham Park.
  • Georges River and Catchments CMP: CMP Stage 1 has been completed by Georges Riverkeeper, with a focus on improving the ecological health of the river.
  • Port Hacking CMP: Stage 1 is set to begin and will be overseen by Council’s Port Hacking Management Sub-Committee. The CMP will focus on balancing the environment and recreation.

Bate Bay dune management

Our coast is dynamic. The beaches at Cronulla and Kurnell are continually subjected to ocean waves and storm surges, which cause short-term beach erosion and long-term beach recession.

As part of our Bate Bay CMP, we work with NSW Government’s Soil Conservation Service who act as the site manager on behalf of Council and Crown Lands focusing on coastal dune and vegetation management.

This work includes coastal rehabilitation after major weather events, including the 2022 East Coast Low.

erosion at North Cronulla beach Coastal erosion at North Cronulla 2022
Coastal erosion at North Cronulla 1974 Coastal erosion at North Cronulla 1974

Planting vegetation to build up dunes, constructing and maintaining protective fences along the dune system, treating noxious weeds, sowing seed to maintain native vegetation cover, increasing the diversity of plant species and maintaining formal access ways are all part of their expertise.

The 40-year Kurnell Dune Program manages dune stabilisation which benefits our community and natural environment.

40 years of sand dune rehabilitation at Cronulla

Frequently Asked Questions (FAQ) about Bate Bay / Cronulla Seawalls

A seawall is a structure made of concrete, masonry, rocks, or sheet piles built parallel to the shore to protect the inland area against wave action and prevent coastal erosion. Seawalls are typically massive structures designed to resist storm surges and erosion.

The seawalls are designed to provide permanent protection against coastal erosion, which has significantly impacted the beaches in the area. They are part of the Bate Bay Coastal Management Program aimed at safeguarding the coastline and enhancing public access and amenity. They help to stabilise the shoreline, reduce erosion, and safeguard the community from potential damage caused by storms and rising sea levels.

Seawalls can impact local marine ecosystems by altering natural habitats. We are mindful of these effects and works to balance coastal protection with environmental conservation. Where possible, environmentally friendly materials and designs are used to minimise impact on marine life.

When it comes to beach and sand replenishment, there are typically a few strategies that we use to address erosion and maintain beach quality. Here's an overview of common approaches:

Natural Replenishment: This approach relies on natural processes to restore beach sand. Councils might work to preserve or restore natural sand sources, such as dunes or coastal wetlands, which can help replenish beaches over time. Sometimes this includes managing vegetation to stabilise dunes and prevent further erosion.

Beach Nourishment Projects: This may involve adding sand to the beach from other locations. These projects are usually undertaken when natural replenishment is insufficient or too slow. They can be periodic or one-time interventions, depending on the erosion rates and the specific needs of the beach.

Beach Scraping: Beach scraping is the movement of sand from the intertidal zone to the dune or upper beach by mechanical means. Beach scraping mimics natural beach recovery processes but increases the recovery rate compared with natural processes. Beach scraping differs from beach nourishment in that nourishment involves sand being imported, whereas with beach scraping, sand is redistributed within the littoral system. This redistribution used in scraping means that natural forces may do some of the work, potentially resulting in lower costs than nourishment.

Dune Restoration: Rebuilding and stabilising sand dunes can help protect the beach from erosion. This might involve planting vegetation, installing sand fencing, and managing human activity to ensure dunes can develop and stabilse effectively.

Community Engagement: Educating and involving the local community in beach conservation efforts can help reduce human impact on coastal environments and support natural replenishment processes.

These methods vary in effectiveness based on local conditions, such as the rate of erosion, the source of sand, and environmental considerations. We will assess these factors and choose the best approach or combination of approaches for their specific needs.

We regularly inspect the seawalls and access tracks to assess their condition. Any damage or debris is promptly addressed to ensure the safety of beachgoers and maintain clear, accessible paths to the beach, subject to available resources and conditions. If you notice any damage, please report it to us.

The community can play a vital role in protecting our beaches by following guidelines, respecting the natural environment, and participating in beach clean-up efforts. Reducing litter, avoiding walking on dunes, and supporting our initiatives also contribute to preserving the beauty and safety of our coastline.

Exposed old seawalls can pose hazards to surfers and beachgoers. Like any historical structure, they may present risks. It’s important to be mindful of their condition and potential dangers. We encourage everyone to stay clear of these areas and follow any posted warnings or guidelines to ensure their safety.

We are committed to the long-term maintenance and improvement of the seawalls. Regular assessments are conducted to ensure the seawalls remain effective, and any necessary repairs or upgrades are made in a timely manner. We explore new technologies and methods to enhance coastal protection.

For more detailed information about the seawalls and ongoing coastal management efforts, please contact us.

Estuaries

Estuaries are defined by the interplay of daily tides, ocean swells and freshwater inflows.

This constant water movement causes the continual shifting of marine sands in Port Hacking. Fine sediment from local catchments and estuaries collect at the heads of the bays in Port Hacking and in the Georges River. Fluvial flooding of the Woronora River estuary is influenced by downstream water levels in the Georges River.

Since European settlement, flat, low-lying areas at the heads of the estuarine bays have been progressively reclaimed for landfill, playing fields and urban development. These areas are subject to oceanic, hydrological, ecological and geomorphologic processes.

Regional collaboration

Sutherland Shire Council is an active member of Georges Riverkeeper and the Sydney Coastal Councils Group. These groups advocate for improving the health and resilience of our coasts and estuaries.