Smart solutions for better city, better life (2)

No 2: Rainfall collection

Australia's Melbourne showcased a project called the Darling Street Stormwater Harvesting.

The project collects rainfall into a tank built underground and irrigates neighboring parks and trees along the streets with the treated stored water.

The project provides an alternative water source for irrigation, according to Ralf Pfleiderer, a water-sensitive urban design coordinator.

"Melbourne rains a lot in winter but is very dry in summer so the project can help store water in winter and offset the water shortage in summer," he says.

From 2000 to 2010, the city saw much less rainfall than usual and a lot of trees suffered from the drought, prompting the city to initiate the project in 2009 and began operation in 2011.

The cost of reusing the rainwater is up to 75 percent less than using tap water and the project also brings other benefits such as reduced demand on the city's water storage for irrigation, improved water supply to parks and gardens, and reduced flow of run-off into waterways, according to Pfleiderer.

It is also a good means to mitigate floods, he says. "We can empty the tank as quickly as possible before heavy rains come."

The capacity of the current tank is 450 cubic meters and the city plans to build another tank with a capacity of 5,000 cubic meters under a park and a third one with the capacity of 2,500 cubic meters under a building.

"Similar rainfall storage projects could be introduced to cities such as Beijing, which has water shortage," says Pfleiderer.

As a city with a population of more than 20 million, Beijing is using every means it could to offset water shortage. They include excessive exploitation of groundwater and water transfer from neighboring provinces.