24/08/2026
The Phosphorus Awareness Project is a partnership between SERCUL and DBCA’s Swan Canning Waterways Branch. Our aim is to help the community understand the impacts of excess nutrients entering our rivers, wetlands and, ultimately, the ocean.
The devastating algal blooms that affected South Australia are a stark example of why nutrient awareness matters. A recently released report suggests that nutrient-rich floodwaters, coastal upwelling and a marine heatwave all contributed to the event.
As the report highlights, harmful algal blooms (HABs) are a growing global environmental and socio-economic issue. They can cause mass mortality of fish and other wildlife, contaminate seafood, affect human health, and result in prolonged closures of fisheries and aquaculture, with significant impacts on tourism and coastal communities.
We don’t want to see an event of this scale and magnitude occurring in Western Australia.
HABs already occur in our Swan and Canning rivers and wetlands. While nutrients are not the only factor that contributes to algal blooms, excess nitrogen and phosphorus can fuel their growth. These local events are an important reminder that we need to manage the nutrients entering our waterways.
What can you do to help?
🌿 Support appropriate tree planting. Ask your council to avoid planting deciduous trees close to waterways or on verges. Deciduous leaves are dropped in autumn and can be washed directly into waterways, or through stormwater drains, with the first winter rains. They decompose quickly, releasing nutrients. In contrast, local native species shed leaves throughout the year and generally decompose more slowly.
🍂 Keep soil, leaves and grass clippings off roads and out of drains. Anything that ends up on the road can be washed into stormwater drains and ultimately into our waterways.
🐕 Pick up after your pets. Dispose of pet waste appropriately so its nutrients don’t end up in our waterways.
🌱 Plant local native species. Native plants suited to your local soil generally require little or no additional fertiliser once established.
🌾 Only fertilise your lawn when it needs it. If your lawn is healthy and growing well, it probably doesn't need additional nutrients. Look for genuine signs of nutrient deficiency, such as yellowing despite appropriate watering, before applying fertiliser.
🧺 Choose phosphorus-free laundry detergents. Look for the NP (No Added Phosphorus) symbol on laundry products.
🚗 Wash cars and boats carefully. Avoid using detergents on driveways where nutrient-rich wash water can flow into stormwater drains. Wash on grass or another area where the water can soak into the ground, or better still, visit a car wash where they can recycle the used water.
Every little bit helps. The nutrients we put on our gardens, lawns and properties can ultimately make their way into our waterways. By making informed choices, we can all help protect the Swan-Canning system and our coastal environment. 💧🌿
A report reveals what caused South Australia's most devastating algal bloom crisis — 16 months after it first appeared on the state's waters.
