HKU researchers call for more sustainable drainage systems

The Hong Kong government is being urged to promote a drainage system that addresses the city’s environmental needs, such as green rooftops that can absorb and store water and porous pavements.

Researchers from the University of Hong Kong’s engineering faculty warn the city is falling behind developed nations and are pushing government departments to implement sustainable stormwater drainage systems that can reduce adverse impacts on the environment, promote greenery, increase freshwater supplies and mitigate the heat island effect caused by human activities.

“The idea is to use a natural method to let the environment absorb water,” said May Chui Ting-fong, assistant professor of civil engineering, adding that sustainable systems can improve water quality and the health of residents in the area, as well as store and conserve water.

“Other countries use sustainable drainage systems but Hong Kong only has a few places. There are many opportunities.”

Greenery such as flower beds could be retrofitted to become a bioretention system that allowed surface water to flow into the greenery area, while watercourses could be covered with a green surface layer to allow water to filter through at a slower pace – an important flood control technique.

Although the Drainage Services Department has made attempts to naturalise drains and pipes, the system still focuses on flood control and is not built to preserve the environment, according to Chui.