Experts have hailed Dubai’s planned Dh30bn rainwater drainage network as a crucial way to guard against flooding, avoid financial losses and stave off the worst effects of climate change.
Flooding alone can cause huge financial damages, with climate change expected to lead to warming temperatures, more rain and severe weather in the Gulf putting pressure on countries to act.
But effective drainage systems can tackle this and are vital in cities such as urban Dubai, where the population has swelled to 3.7 million, they say.
Nidal Hilal, professor of engineering and director of NYUAD’s Water Research Centre said the move was a “proactive approach” that would “safeguard the city’s future” against such catastrophic losses and enhance its resilience against climate-related challenges.
“Drainage systems are a cornerstone of sustainable urban development, impacting everything from economic growth to public health,” said Prof Hilal.
“Such infrastructure is not only about water management but is pivotal in securing a city’s economic stability and environmental sustainability.
“These systems mitigate flooding risks, which can cause millions in damages – take for instance the estimated $60 billion in annual global flood damage,” he added.
The Tasreef system, meaning drainage, aims to increase Dubai’s rainwater drainage capacity by 700 per cent, meet the emirate’s needs for 100 years and make sure the city is ready to face “climate-related challenges”.
Further details were not released but a map published by Dubai Media Office showed the scale of the project ranging from Dubai South to Business Bay to the border with Sharjah with photographs also showing huge drainage tunnels.
The development also comes just two months after a powerful weather system hit the UAE, bringing record amounts of rain that flooded parts of the city and caused major travel delays. Experts said the plan will go some way to tackling this problem.
Vision to tackle wetter weather
Dr Diana Francis, an assistant professor who heads the Environmental and Geophysical Sciences (Engeos) Lab at Khalifa University in Abu Dhabi, said rain is expected to increase by “more than 30 per cent by the end of the century” in the colder months with extreme events to become more frequent. Dealing with climate change then, requires “innovative solutions on several fronts”.
“The drainage system is one of them and will help to address the projected changes in rainfall over the region,” she said.
Dr Martijn Booij, an associate professor at the University of Twente in the Netherlands, said urban areas were facing greater threats from extreme rainfall because of climate change.
Urban planners faced “uncertainty” because there were various scenarios about how the world's emissions would change over time, and each was associated with a range of potential effects on rainfall with the general tendency to “more extremes”.
“That requires you to design your drainage system taking the future into account and taking the uncertainty into account,” said Dr Booij.
Global and regional challenges
According to the UN, at least 68 per cent of the world's population will live in urban areas by 2050. This places strain on legacy drainage systems that were built for a different era with “inadequate capacity, poor maintenance, and outdated design” contributing to their inability to cope with extreme wet weather,” said Prof Hilal.
He said inaccurate data and insufficient monitoring compound the problem with new systems needed to cope with the larger volumes of stormwater.
Several factors also needed to be considered when these types of projects were planned.
“These include accurate projections of the rainfall intensity and frequency during the coming decades; assessment of the groundwater levels; evaluation of the urban expansion of the city and the build environment in the future; the materials to be used that will have to cope with extreme temperatures; the energy required to run such systems and that can be relied on during extreme weather,” said Dr Francis.
The Middle East faces its own set of challenges, said Prof Hilal because increasing water scarcity meant countries needed to invest in modernised infrastructure and implementing sustainable water practices to deal with a changing climate and challenges of urbanisation.
“The challenge is compounded by increasing instances of intense rain events that are infrequent yet severe,” said Prof Hilal.
How difficult are these types of projects to build?
Once complete, the rainwater drainage capacity is expected to be 20 million cubic metres of water daily with a flow capacity of 230 cubic metres a second. The project is a continuation of drainage projects launched in 2019 that encompassed much of Dubai South, location of the new Al Maktoum Airport.
Prof Hilal said these types of projects are costly and “technologically demanding”. “Their planning and execution involve hydrological modelling and the integration into existing city infrastructures without major- disruptions,” he said.
Dr Booij said that drainage systems were known as “grey infrastructure” and that in many areas there was also investment in “blue infrastructure” and “green infrastructure” to manage water.
Blue infrastructure may include large bodies of water that take in significant quantities in the event of extreme rainfall, while green infrastructure describes areas such as sunken gardens, sometimes called rain gardens, that can collect rainwater run-off.
“You see a combination of blue and green measures and grey measures like urban drainage systems,” he said. “You need some grey infrastructure as well to discharge the extreme rainfall events.”
It is also important that planners add more greenery that can help rainwater to easily “penetrate the ground”, said Dr Francis and it would be positive to see the planned system include a phase where the collected water will be “treated and used for several purposes” instead of being evacuated to the sea.
“As an arid country, the UAE can really benefit from the increase in rain to transform it into an additional source of water,” she said.
Blueprint for the future
Dubai Municipality will oversee the project and it is expected to be complete by 2033. It is envisaged as the largest rainwater collection project in a single system in the region.
“While in many other parts of the world, a lack of political will often discourages advances in technology development, the UAE leadership continuously emphasise the instrumental role of innovation, as they lead the way in responding to environmental challenges,” said Prof Hilal.
“Tasreef is yet another example of the UAE’s commitment to adapt to changing conditions by upgrading infrastructure to handle extreme weather while improving economic stability.”
