An algal bloom is currently covering large areas of exposed water at Horseshoe Lake and residents are being advised to avoid direct contact with the water.
The bloom has been analysed by the Department of Water and Environment Regulation (DWER) and contains three species of harmless macro algae and low densities of blue-green algae which are considered to be of low concern at this stage.
As a precaution the City of Bunbury has erected standard health warning signs around the wetland and will continue to monitor the bloom over the coming weeks.
Algae is a natural part of the wetland system but large blooms can occur with the onset of warmer weather when water in the wetland becomes too rich in plant nutrients, especially phosphorous and nitrogen, much of which can be attributed to our use of garden and lawn fertilisers at this time of year. Locally applied fertilisers enter the wetlands through stormwater pipes or leaching into the ground water.
Residents can help in keeping our waterways healthy by following a number of recommendations:
- Only apply fertiliser, if required
- Apply fertiliser in accordance with directions during Spring or early Autumn, when plants are actively growing
- Do not over-water as this washes fertilisers into water ways
- Improve the soil with organic matter and other additives to improve nutrient retention
- Grow native or water wise plants which require less fertiliser and water
- Use water and fertiliser efficient grasses such as Buffalo and Zoysia
- Reduce the areas of lawn
More information on how to use fertiliser responsibly is available on the following websites: www.homeriverocean.com.au and www.fertilisewise.com.au