The modern water cycle has been drastically altered from our historical depiction of forested catchments, regular rainfall, average water demands, and sufficient environmental flows. Nowadays, the water cycle is more “unconventional” with variable rainfall and a rise in the application of water harvesting technologies such as wastewater reuse, desalination plants, and stormwater capture, leading to dramatically reduced environmental flows.
Climate variability poses a risk to our water supplies via three main pressures:
- increased rainfall variability and intensity leading to increased flooding risk
- decreased, less frequent rainfall leading to extended durations of drought
- warmer temperatures increasing evaporation from catchments and reservoirs.
Extreme Climate Challenges: Flood and Drought
South East Queensland’s sub-tropical climate makes it prone to weather that can cause flooding. When it rains – sediment (mud), chemicals and litter are washed into stormwater drains and carried straight out into our waterways where they negatively affect waterway health and threaten aquatic plants and wildlife. During the January 2011 and 2013 floods, millions of tonnes of sediment were washed off the land and into our waterways and Moreton Bay.
Drought has been recognised as a natural characteristic of Australia’s variable and changing climate. South East Queensland is one of the areas hardest hit, with the frequency and extent of exceptionally hot years and exceptionally low soil moisture years likely to increase in the future.
Agriculture in Queensland has recently been valued at worth over $9 billion* to our local economy. Higher temperatures and levels of evaporation associated with drought impact on available water supplies, preservation of soil and pastures and the availability of feed. These pressures can disrupt cropping and harvesting schedules or result in reductions in breeding stock which push up pricing of produce to the consumer and affect the economy.
* Hon. Tim Nicholls, Queensland Treasurer and Minister for Trade - 29 September 2014
Household products such as paint, oil and detergent contain a range of toxins that are hazardous to aquatic wildlife and degrade water quality. During heavy rain and floods, a greater amount of chemicals enter our waterways. These excess chemicals can cause severe impacts, such as mass fish kills and toxic algal blooms.
Healthy Waterways Action
Healthy Waterways is working with our members to better prepare our catchments for extreme weather events through managing erosion, stabilising creek channels, rehabilitating riparian (riverbank) areas, investing in agricultural practices and applying water sensitive urban design.
In our region, annual rainfall in urban areas exceeds annual water use. When it rains, most of this water simply runs off into our rivers and streams. Many feel this is a wasted resource that could be put to better use. We conduct training and publish guidelines on this topic.