The Dutch way with water
After centuries building dykes, the Dutch adopted a pragmatic approach to rising water levels: living in harmony with water rather than trying to control it.
29 MAY 2019
Singapore has a big water challenge. Demand in the city-state is around 430 million gallons a day, enough to fill 782 Olympic-sized swimming pools. Domestic consumption accounts for almost half of this – a figure that could almost double by 2060, according to Singapore's national water agency, the Public Utilities Board (PUB). Surrounded on all sides by sea and vulnerable to heavy downpours, the region must also contend with flash floods.
Against this backdrop, Singapore developed a now world-renowned water management programmes, sinking S$670m (£382m) into research and development. PUB has formed collaborative ties with leaders in private industry and academia, including GE Power in North America and Israel's national water company, Mekorot, to de-risk and scale up promising technologies.
The agency says this collaborative approach has resulted in half the projects carried out under its R&D programme progressing to implementation or the next development phase. To date it has worked on 613 projects with partners from 27 countries. PUB also works with bodies such as the Ministry of Education, and Housing Development Board to educate teachers, students and homeowners on water scarcity and management. Last year it began a two-year deployment of smart shower devices to around 10,000 flats to conserve water.
Elsewhere the city-state has made a series of infrastructure investments to create "four national taps", which come from local water catchment, imported water, desalinated water and reused/recycled water – what it calls "NEWater". Currently, desalinated water supplies up to 25% of Singapore's water needs, with NEWater making up to 40% but the city-state intends for these two sources to account for 85% of Singapore's water needs by 2060.
Rainwater and grey water collected via drains, canals and rivers is channelled to one of 17 reservoirs. Since 2011, these local water catchment areas have grown; from once taking up half its land surface, to now two-thirds. The city also imports water from the Johor River in Malaysia – an agreement that runs until 2061. Two desalination plants currently meet 25% of Singapore's water needs, with three more due to come online next year. Finally, the region has five reclamation "NEWater" plants, which use a three-step treatment process to produce clean water: microfiltration and reverse osmosis remove contaminants and bacteria, while ultraviolet disinfection kills any remaining organisms.
Water is a precious commodity in drought-afflicted Australia. Consequently, the main city authorities have adopted water-sensitive urban design (WSUD) principles in their planning legislation, which treat storm and sewage water as a resource rather than waste. In Melbourne, WSUD examples include protecting and enhancing natural water systems within urban developments, and integrating stormwater treatment into landscapes such as parklands. Water draining from urban developments is filtered to remove pollutants and retained to reduce runoff in the event of floods.
Low-impact development (LID) is a term used across the US and Canada to explain a "design with nature" approach to managing and minimising stormwater runoff. The aim
is to use green infrastructure to mirror nature wherever possible, thus ensuring any new development has minimal impact on the environment. This is achieved by incorporating natural features such as trees, wetlands, drainage patterns, topography and soils – an approach that creates areas for local water storage, and drainage systems that are distributed across the landscape.
A by-product of urbanisation is the spread of impervious surfaces such as concrete and asphalt that repel rainwater, rather than allowing it to soak into the ground. In the event of heavy downpours, this can lead to flash flooding. The sustainable urban drainage systems adopted in the UK use various forms of permeable surfaces to manage drainage, such as green roofs to control water runoff and permeable paving that allows rain to pass through the surface. These measures help to direct the flow of water to natural features such as streams and lakes, thus preventing local sewer networks becoming overwhelmed.