Exploring an innovative design for sustainable urban water management and energy conservation

Large areas of our cities are taken by impervious areas, which reduce infiltration and increase peak flows, leading to flash floods and rendering less water for storage and use. At the same time, urban water demand is growing at an unsustainable pace. An innovative system design combining permeable pavements with underground water storage is proposed to reduce runoff peaks, store water, treat pollutants, lower ambient temperatures (heat island effect), and harvest energy from the heated pavement. The proposed system is highly exploratory and aims to answer questions such as what existing technological options could be used, how are the elements of the system integrated, and what are the potential benefits?Through a prototypical case application in an industrial area in Singapore, it was found that the proposed system could significantly reduce runoff and peak flows and slow the recharge of underground water storage. The sizes of urban drains can therefore be reduced significantly, thereby freeing up valuable urban space – a primary sustainability concern in crowded urban cities. We also found that the proposed design solution has not satisfied decision and policy-makers on energy-harvesting and heat-island-effect reduction. We conclude by discussing our lessons learnt from the exploratory study from the technical, economic, and sustainability perspectives.