Just published research from the ARC Centre of Excellence for Climate System Science called, ‘Future increases in extreme precipitation exceed observed scaling rates’ (http://go.nature.com/2iFybub) This research says we can expect “strong increases in rainfall during extreme precipitation events in Australia as a result of global warming.”
A 2°C rise in global average temperatures, is expected to cause an 11.3% to 30% intensification in rainfall from extreme precipitation events in Australia. Other areas will be more susceptible to drought.
The researchers looked at the likely outcomes of a 4°C rise in global temperature & found “a projected increase in rainfall for extreme events of 22-60%.” A 4°C rise in global temperature “is a likely outcome based on current increases in the rate of carbon emissions.” See – http://bit.ly/2jlUfMs
More intense rainfall extremes will likely cause a problem with stormwater, so it is just not an issue of sea-level rise, but also more rain, which has to go somewhere.
Nature did not expect that our cities & suburbs would be covered in vast amounts of concrete & other impermeable surfaces like roofs & roads. If rain water cannot seep into the ground, it will flow over the hard surfaces following the slope of the land until it reaches an area where it collects. Many of our streets do this naturally & become hazardous areas during a heavy downpour. Imagine what these will become during “intense rainfall extremes.”
In the Inner West, our sewerage / stormwater infrastructure is aging & “at capacity” – or so I once read in a Marrickville Council paper on the subject. The level of new development, predominantly high-rise, will significantly add to this load, so I guess we need to expect more flooding.
Inner West Council (nee Marrickville Council) has done quite a bit of work building swales & raingardens around the Cooks River. Once water is in the swale or raingarden, it can seep into the ground naturally. This process cleans it of pollutants such as oil, grease, particulate matter, litter, heavy metals & fertilizers before the water reaches the river or replenishes groundwater stores.
Until I read about it I had never considered that litter tossed in the street at Newtown or Enmore could reach the Cooks River & I am sure most people don’t think about or know of this either.
Council has also been slowly creating verge gardens for a number of years. These not only cool the streets & add beauty & pockets of habitat, they also help capture stormwater.
Things we can do to help with stormwater management –
- Choose to have as much ground surface available on our property. This means not creating large expanses of concrete driveways or concreting our back & front gardens. All water that runs off your property causes a problem somewhere else.
- Depave any unnecessary concrete in your property. Every bit of depaving helps.
- We can agree to a street tree out front if Council asks us & look after it if one is planted. Trees are very good at capturing the rain & holding it in the canopy. Rainwater either slowly drips to the ground or is absorbed into the atmosphere by the process of evapotranspiration.
- Create & look after a verge garden.
- Plant tree/s & add living plants to everywhere we can – ground, roofs & walls.
With all the development happening or about to start across Sydney, local councils & planning bodies would do well to insist that developers retain as many mature trees as possible on development sites. Instead of installing underground pipes to take stormwater from the site to the collective sewerage system, it would be better if they did not over develop the site & planted more big canopy trees & other vegetation as these would help slow down some of the stormwater. Adding a raingarden would be good too.
Our city is changing rapidly. Climate change is happening & expected to worsen. How well we live & our quality of life very much depends on how we create our environment. We will be much better off if we depave, if we plant medium to large growth trees & if we add living plants to everywhere we can – ground, roofs & walls. We need to start to plant to keep cool & to help manage stormwater.