Engineer are developing new types of permeable paving materials to help urban areas weather the storms and floods that are afflicting coastal regions with increasing frequency.

Permeable pavements may soon become preferable in many urban areas to conventional surface coverings of an impermeable nature, such as stone or dense asphalt, as global climate change increases rainfall volumes and raises sea levels.

In Scandinavia VTT Technical Research Centre of Finland is experimenting with permeable pavement solutions that are suitable for those surface areas that receive to low traffic levels, such as car parks, courtyards and public squares.

The company recently completed its two year CLASS (Climate Adaptive SurfaceS) project, which sought to produce innovative permeable pavement solutions for Nordic weather conditions, using materials that mark a significant departure from conventional methods.

The permeable pavement developed by the project consists of a surface layer and sub-surface material that possess a high level of porosity, enabling it to retain water during heavy rainfall and help prevent flooding when urban drainage systems are overwhelmed.

High water infiltration is also facilitated by the use of porous materials in the joints or openings of the pavement system.

“The pavement solutions developed in the project can help in mitigating urban flooding caused by large volumes of water entering the storm water network,” says VTT’s Project Manager Erika Holt.

The CLASS project successfully verified the water infiltration capacity as well as winter durability performance of the permeable pavement structure through out its full service life, throughout all stages of development and usage including design, installation and lifetime maintenance.

Finland is not the only country to adopt permeable pavements, with the systems already widely employed in Japan, the United States and Australia.

According to Dr. Baden Myers, a research engineer with the Centre of Water Management and Reuse at the University of South Australia, permeable pavement systems have proved to be especially well suited to those parts of Australia that possess the appropriate soil and ground conditions.

“With good subsoil for infiltration, [permeable paving] provides a means of drainage where access to conventional ‘pit and pipe’ infrastructure is difficult,’ said Myers to Sourceable. “In an environment where water can infiltrate quickly and access to a drainage line is difficult, it can be a very good means of providing drainage.”

“An example of this is in the City of Charles Sturt in Adelaide, where due to access issues local government uses permeable paving in laneways purely for drainage purposes.”

Image of permeable paving at Sydney Olympic Park

Other noteworthy permeable pavement installations in Australia include a large parking and pedestrian area on the western side of the Sydney Cricket Ground near Driver Avenue; partial surfacing around Olympic Boulevard at Sydney Olympic Park, residential streets in the Sydney suburb of Manly, and car parking areas in several parts of Adelaide.