Water Quality
Stormwater
When it rains in Leichhardt, water either soaks into the soil or runs over the land through creeks and channels and eventually into the sea. Due to the high level of hard and impermeable surfaces in Leichhardt (eg roads, industrial and commercial sites, roof tops and paved areas) most of the water runs over the land into stormwater drains. This water is called stormwater.
As stormwater flows through gutters, pipes and channels, it can pick up a variety of pollutants which will eventually flow into the sea, degrading the water quality of receiving water bodies and therefore impacting on local ecosystems. Pollutants that are picked up along the way often include:
- Oils and grease from cars
- Litter left on the ground
- Sediments from construction sites
- Leaf litter Chemicals including pesticides, fertilizers and cleaning products
- Dog droppings
Leichhardt LGA is bounded by water on its northern, eastern and western sides. Since early last century, the water courses running through the LGA including Johnstons Creek, Whites Creek and the Hawthorne Canal have been concrete lined and straightened and are now devoid of riparian vegetation. Mangrove swamps and saltmarsh communities that once boarded these waterways have been reclaimed and filled in to form parkland.
Stopping pollutants from entering waterways is a difficult task as the source of pollution is often hard to identify. To prevent large litter items entering the harbour, Council has installed several capturing devices including litter baskets and Gross Pollutant Traps (GPTs). However, these devices are not ideal as they do not stop the source of pollution; rather they are ‘end of pipe solutions.’ The best protection against stormwater pollution is preventing it at the source before it enters the stormwater system.
Here are some helpful things you can do to prevent stormwater pollution:
- Check your car for leaks and keep it well maintained
- Correctly dispose of all your litter in appropriate bins
- Ensure that sediment does not escape from construction sites
- Use controls such as sediment fencing
- Sweep paths and gutters to remove leaves and lawn clippings
- Avoid the use of pesticides in the garden
- Always clean up after your dog
In 2006, Council introduced a stormwater management service charge on the rates. This will raise around $500,000 pa to improve management of both stormwater flooding and pollution in the Leichhardt area. Actions for 2006 -07 include rerouting stormwater away from Dawn Fraser Pool and carrying out a feasibility study on the harvesting and reuse of stormwater.
Monitoring of Waterway Quality and Health
Water quality is currently being monitored at the following sites in the LGA:
- Hawthorn Canal – by Kegworth Public School
- Whites Creek wetland – by St Scholastica’s College
- Whites Creek – by Leichhardt High School
All the monitoring by schools is undertaken as part of the Streamwatch program. Streamwatch is a school and community education and action program that raises awareness of the natural environment through testing water quality in local rivers and streams. The program empowers groups to protect the health of local waterways through their involvement in water quality monitoring.
Monitoring planned for the future at Whites Creek Wetland includes:
- Ongoing water quality monitoring of inlet, pond and outlet water
- Ongoing Streamwatch water quality monitoring
- Periodic sediment testing for heavy metals
- Reptile surveys
- Frog monitoring
- Bird monitoring
- Aquatic invertebrate (water bug) monitoring
Wetlands
Wetlands ecosystems are important habitats for a variety of animals and provide natural services such as filtration of stormwater.
Wetlands naturally treat stormwater in low flow conditions through physical processes such as filtration through reeds, settling of particles and biological processes such as removal and breakdown of nutrients in the water and small organisms breaking down organic matter. Wetlands also increase the diversity of habitat available to urban wildlife.
In 2001 an artificial wetland was constructed at Whites Creek. Water is pumped from the Whites Creek channel into the upper section and then trickles through a series of ponds before re-entering the creek. The wetland makes for a pleasant walk and features a wide array of flora and fauna. This small wetland does require ongoing maintenance but it provides significant habitat and water quality benefits as well as an opportunity for hands-on community learning.
In addition, the wetland is used as a tool for education & awareness raising about the sources and effects of pollution on our waterways. In time, this increased awareness in the community should reduce the amount of pollution entering the stormwater system. This should eventually result in cleaner water in Whites Creek and less pollution reaching Rozelle Bay and Sydney Harbour. Interpretive signage has been developed and installed at the wetland. The new signs provide information on the wetland processes, the important function that Whites Creek plays and some of the wildlife that can be seen in and around the wetland.
Whites Creek enters Rozelle Bay and any pollution entering the creek will affect the ecology of the wetland and the health of the harbour.