River Torrens Recovery Project
Improving the River Torrens from the foothills to the sea
NEWS UPDATE: A new project is building homes and growing food to help our native bees.
The lower River Torrens crosses through the highly urbanised Adelaide Plains from Athelstone to the sea and provides essential drainage and flood management to the Adelaide metropolitan area. Torrens Linear Park is a refuge for urban wildlife, pollinators, and offers peaceful recreation opportunities for people.
The waters of the lower River Torrens Karrawirra Pari are fed by rainfall over Adelaide’s metropolitan area and foothills and flow through the park, past ancient river red gums and reed beds. These features hold important cultural significance to the Kaurna people – the Aboriginal people of the Adelaide Plains.
However the lower River Torrens is vulnerable to the impacts of this built environment with contaminants entering the river with stormwater runoff, which pollutes the water.
This River Torrens Recovery Project commenced in 2014, targeting priority sites to improve water quality and ecosystem function in the river and the coastal waters where it enters the sea.
Through the ongoing commitment of the eight councils along the linear park, and the Adelaide and Mount Lofty Ranges Natural Resources Management Board, the River Torrens Recovery Project continues to improve water quality and habitat for our native wildlife.
Dealing with stormwater
Before urbanisation, rainfall largely soaked into the ground, only running into creeks and rivers during heavy falls or when the ground was saturated. Today, rainfall runoff flows quickly across pavements, roads and carparks taking pollutants with it such as oil, cigarette butts, plastic litter, dust, leaves and dog poo to the nearest creek. Polluted stormwater flows directly to the nearest creek without being treated. It carries high levels of nutrients which can cause algal blooms and smother seagrass and reef systems.
How do gross pollutant traps and water sensitive urban design help?
Gross pollutant traps and water sensitive urban design structures, such as roadside raingardens, improve water quality by capturing leaf-litter, urban rubbish and sediments before they enter watercourses. Raingardens also filter pollutants from water as it percolates through the soil profile before it then enters drains and watercourses.
Dealing with exotic trees
Leaf drop from exotic trees increases nutrients in the water and lowers oxygen levels necessary for aquatic animals to survive. This can result in poor health and even death of aquatic animals that live in and rely on these waterways.
The roots of some exotic tree species can also cause a loss of habitat, and river bed and bank stabilisation is impacted by exotic tree roots leading to erosion.
Removing invasive exotic trees and replacing them with locally indigenous plants improves the Torrens’ water quality and the native habitat features of Torrens Linear Park.
What else is being done?
Key actions include weed control, revegetation with native plants, stabilising river banks and reducing litter and pollutants from entering the river through the installation of pollutant traps. Large volumes of the destructive European Carp have also been removed from the Torrens Lake.
These works also complement a number of other projects and programs in the catchment and the project continues to evolve as lessons are learnt and opportunities to increase collaboration are identified.
People and the park
The success of the project and the support of the local community has seen this project extend beyond the initial two years of funding provided by the Australian Commonwealth Government.
See what River Torrens Linear Park visitors had to say about this project. Read the report on the community survey.
Native Bee ‘n’ Bug hotels
The project now involves the community in construction of Native Bee ‘n’ Bug hotels along our iconic River Torrens. Native bees are important pollinators for many of our native plant species. Find out how you can be involved.
Be part of the solution
Everyone can help improve the water quality of our creeks, rivers and oceans.
Keep run-off surfaces free of pollutants – bin your cigarette butts, clean up oil leaks, cut down on plastic usage, wash your car at a car wash or on a grassy area – not on the street. Remember that the stormwater drain flows directly to the nearest creek and the water is not treated.
Want to do more?
Get rid of invasive exotic plants in your garden or install a raingarden.
Manage pest plants.
Join a Friends of Parks or Bushcare volunteer group to help care for essential habitat for local native species.
Want to know more about a site?
City of Charles Sturt – Kelly Mader (08) 8408 1208
City of Norwood Payneham & St Peters – Martin Woodrow (08) 8360 9008
City of Port Adelaide Enfield – Andy Walker (08) 8405 6600
City of Tea Tree Gully – Brad Mann or Mick Medic (08) 8397 7444
Town of Walkerville – Joshua Bowen (08) 8342 7100
Campbelltown City Council – Henry Haavisto (08) 8366 9285
Overview Natural Resources AMLR – Joseph Sullivan (08) 8273 9100
The project in detail
Why remove exotic trees?
Most exotic trees along the River Torrens come from Europe, are deciduous and lose their leaves in autumn.
Whilst this can be visually spectacular, autumn leaf drop smothers aquatic habitat, creates barriers to flow, produces localised flooding and increases nutrients in the water as a result of the breakdown of organic matter. This results in unsuitable water quality for our native aquatic plants and animals.
When these nutrients flow out to sea they can impact on the coastal and marine environment, especially Adelaide’s coastal seagrass meadows. These meadows stabilise the near shore sands and provide habitat for many of our commercial and recreational fishing species.
Increased nutrient levels also promote algal growth which smothers seagrass leaf blades, reducing the amount of light available for these grasses to photosynthesise and grow.
Exotic trees that sucker and produce dense growth can block and divert the flow of water which sometimes leads to erosion and localised flooding. Poplars, ash and willows all exhibit this behaviour.
Willows produce a dense root mat which can build up the watercourse bed and reduce flow capacity. These dense roots stop native water plants from establishing. The increased shade of exotic trees also makes it hard for native water plants to grow.
So removing exotic trees reduces blockages and increases flow capacity. This helps reduce flood risks by increasing the volume of water held in the watercourse and decreasing the time it takes to reach the sea.
How is local native vegetation different?
Our native trees also drop leaves, but they drop and replace their leaves in a more even pattern throughout the year, rather than contributing a large quantity of organic matter to watercourses over a short period.
Native trees do not sucker or produce dense growth to the same extent as some exotic trees.
Native trees produce hollows which provide a home for many of our local birds, bats and possums to nest. They also provide the best food resource for our native animals.
Why remove European Carp?
The destructive feeding habits of European Carp lead to reduced water quality which in turn has negative impacts on native aquatic plants, animals and general river health.
European Carp uproot vegetation and stir up sediments, leading to increased turbidity. They also destroy aquatic plants by direct grazing and uprooting them, which leads to the undermining and erosion of watercourse banks.