Climate change has led to more intense rain events, which is raising questions about the impact on urban stormwater systems.
TheStormwater NSW (franc.sydney)) 2022 Conference on The 29thand 30ThMarch will bring together experts from across the country who will discuss issues related to stormwater management systems in current times and offer solutions.
Michael Smit is the Technical and Sustainability manager at Kingspan Water and EnergyRainwater will be discussed as part of the solution.
Before we discuss the benefits of rainwater harvesting, let’s first address the problem.
In forested areas, only 20 percent of rainfall is carried into waterways. 40% of rainfall is lost to the atmosphere or transpired back into it, while the remaining 40% seeps into water tables through permeable topsoil.
This system has evolved over millions of year and offers many benefits.
The water is evaporated back into the atmosphere through transpiration and evaporation. This has a significant cooling effect, and ensures that there’s enough moisture to support future rains. The water table acts as a constant water source, slowly trickling into the waterways through permeable topsoil. Rivers can continue to flow with cool, clean water even during dry spells.
However, in urban areas, the system is reversed. With 80 percent of the rainfall flowing into local creeks, there is less water returned to the atmosphere.
Impermeable infrastructure such as roads and buildings, also stops rainwater from reaching water tables. Most of the water is forced to flow directly into streams and rivers. Stream ecologies that are adapted to groundwater flow are damaged by fast moving water.
This system causes more floods. However, less transpiration contributes to the heat islands effect and increases the likelihood of future droughts.
We have this very unfortunate effect where it rains, there is far too much water in our streams, and when it doesn’t, the reduced base flows are causing a permanent drought.
It is expected to get worse. The impervious surface of cities is increasing from 65 to 90 percent per block to a constant 90 percent. This makes it harder for water to seep into the ground. This will only exacerbate the climate change effect, already causing major changes in our weather.
The franc.sydney conference aims to find solutions for this growing problem. Mr Smit hopes rainwater harvesting will be part of that solution.
Stormwater management should be done at the source, not through volume reduction. These are recognised by the Australian Rainfall & Runoff Guidelines 2019, which recognize rainwater harvesting’s contributing roles. Although rainwater tanks will not stop riverine flooding like we experienced recently, they can reduce the impact of events up until the one in ten year event which is where most infrastructure spending is directed.
Rainwater harvesting is simple. It involves capturing rainwater in water tanks. The water is then redirected into waterways to prevent it from flowing into the waterways. Rainwater can be used to water the home, wash machines, and flush the toilets.
Rainwater can be used at this level to reduce the need for water storage in dams that further damage river ecosystems. It can also be pumped long distances which consumes a lot of energy.
Michael’s personal vision is for every building to have a small rainwater storage tank for stormwater benefits and water in crisis.
Smart Tank sensor keeps you engaged and informed, and provides useful data for the environment
Kingspan also developed a sensor and software integrated to track the water flow into and out of a water tank.
This allows households to monitor their water usage. It also allows us to identify how many rainwater tank are functioning, how much water is being used and what volume of stormwater has been reduced. We can now understand cities in a new way.
Mr Smit and other experts will have the opportunity to discuss their solutions at franc.sydney and to discuss how they might collaborate to reduce floods and preserve local environments.
Kingspan will discuss the benefits and challenges associated with rainwater harvesting. He will also discuss why South Australia has made it an deemed-to satisfy response. He will also discuss the cost of alternative solutions such as upgrading our stormwater infrastructure.
Secure the conference dates for 29Thand 30ThMarch online via OnAIR platform, or in person at Dockside Darling Harbour in Sydney. Register to Attend https://www.franc.sydney/register-now.
