What is a Catchment?
A catchment is an area of land where water will drain into a central waterbody, such as a river or lake. Thus, any water flowing through a catchment, affects the waterbody. In urbanised areas such as the Inner West, rainwater will run off roofs, roads and footpaths before entering the stormwater system. The water will pick up pollutants along the way, such as pesticides, sediment and litter.
Everyone lives in a catchment and can help improve the quality of local waterways. It is up to everyone to keep local waterways clean.
Inner West Catchments
Inner West sits on two water catchments. Council works to prevent large, small and chemical pollutants from entering the waterways where possible. Council operates 23 Gross Pollutant Traps (GPTs), which remove large pollutants from stormwater runoff prior to entering the main waterways. Additionally, many Natural Areas and Wetlands are managed by Council to filter chemical pollutants, nutrients and sediments from waters flowing across the landscape.
However, preventing a pollutant before ever entering the environment is the best way to improve waterway health. This can be achieved with help from the community. You can help by building water-sensitive design elements on your property, reducing pesticide use, or installing a water tank.
The Cooks River catchment stretches across much of the southern half of the Inner West to the border, where the river itself flows onto Botany Bay. Most of the historical creek lines and wetlands have been lost to development, with many waterways diverted into channels and pipes. Council works to protect, rehabilitate and re-create natural water systems in the Cooks River. In 2026 Council will open the new Gumbramorra Swamp Re-creation site in Mackey Park, Marrickville, and will begin works to restore the natural creek located behind Hercules St, Dulwich Hill.
Inner West Council is a member of the Cooks River Alliance, which partners Councils and organisations within the Cooks River together to work collectively and improve river health. Through the Alliance, Council is proud to promote this unique waterway as Our Backyard River, working towards transforming the Cooks River into the best urban river in the world. To explore the wider catchment, visit the Cooks River Alliance Catchment Map.
The Parramatta River catchment takes up a little over the Northern half of the Inner West, flowing into Sydney Harbour. Similarly to the Cooks River catchment, majority of the natural creeks and waterbodies have been urbanised, developed and diverted. Council works with partners to re-naturalise water features throughout the catchment and manages sites such as Whites Creek Wetlands and Richard Murden Saltmarsh to improve water quality and restore natural processes.
As a proud member of the Parramatta River Catchment Group, Inner West Council collaborates with Council's and organisations across the catchment to achieve a shared vision of making our rivers and waterways swimmable again. Council continues to progress the Callan Park Tidal Baths project and is investigating the feasibility of an additional swim site at Mort Bay.
Get the Site Right is a joint program between the Cooks River Alliance, DPIE, Georges Riverkeeper, the EPA, Parramatta River Catchment Group, Sydney Coastal Councils Group, local Sydney councils and Lake Macquarie Council.
The aim is to help builders and home renovators on best practice erosion and sediment controls.
Sediment run-off usually contains common building materials such as cement, sand and soil. These materials can contaminate water and cause algal blooms that harm marine plants and animals. They can also build up in marine species, such as mussels, and have a dangerous impact on the food chain.
For more information, have a look at the Parramatta River Catchment Group's page.