Joined-up thinking is needed to plan wastewater infrastructure
The practice of developers installing their own wastewater services has raised questions over their ability to cope with rare but destructive downpours, such as the one experienced in Dubai last month. Angela Giuffrida examines what can be done to manage the increasing strains being put on the emirate’s wastewater infrastructure.
Shopping malls were flooded, water gushed through villa walls, motorists were stranded and pedestrians had to navigate huge puddles in the road when Dubai was hit with heavy rain last month.
The sporadic downpours lasted just a few days, but the problems inflicted on property owners in some of the new housing developments across the emirate probably won’t fade as quickly.
Nerves were particularly frayed among villa owners in Emaar developments, including Arabian Ranches and Emirates Hills, along with Nakheel’s Jumeirah Islands, where some homes ended up under several inches of water.
One resident described waking in the morning to water shooting through the wall as “surreal”, and “not something you’d expect in Dubai”.
At its worst, just 14.6mm of rain fell. But the havoc it caused has exposed not only the poor design of some of the housing, but also the emirate’s volatile drainage system.
The average annual rainfall in the coastal areas is less than 120mm.
“People use the excuse that it hardly ever rains in Dubai, but, as we’ve seen, it can rain heavily for just half an hour and cause so much damage — buildings have to be built to withstand this,” said Gopal Prithviraj of PRG Consultants.
“When things like this happen, the interest generated in buying property soon fades because quality products aren’t being built. The first group of buyers might go for it, but it will be more difficult to sell it on. Some British newspapers are already writing about the poor quality of some properties here, which will eventually impact the economy.”
But property developers argue that this is all part of the ‘teething problems’ of newly built homes.
“With every new large-scale development it takes a while
to bed down. And for any new housing development, when it gets its first major storm, there is an impact — it happens in the UK, it happens everywhere,” said James Wilson, who now heads up Nakheel’s new hotel business.
As property owners grappled with the damage done to their villas, the emirate’s roads became clogged with water, leading to a Dubai police estimate of 513 accidents.
Despite investing US $163 million (AED 600 million) on providing more robust sewerage and storm water drainage facilities in certain areas across the city, Dubai Municipality claims that the current storm drainage network is not designed for the immediate clearance of rainwater due to the minimal annual rainfall.
Ongoing sewage and storm water drainage projects in Mirdif, Barsha, Mizhar, Warqa and Murhaisana are expected to be finished in 2007.
A drive is also under way to get building developers to connect their drainage system to the Municipality’s sewers instead of using septic tanks.
“Our preference is to connect to the main pipeline — septic tanks are messy, expensive, unhygienic and cause a whole load of problems — this is not what we want,” said Lesley Ziri, senior manager of property management at Union Properties.
She added that Union Properties has managed to get its Uptown Mirdif project connected, and Motorcity is being designed with a provision for this. But linking up with the Municipality’s sewerage system very much depends on the location of a development.
“In some of our developments we have had no choice but to use septic tanks because the main drain is not available in the immediate areas. But one of the factors about the damage caused by the recent flooding is that a lot of these properties are newly built, and this is the first time it has happened.
“You do get debris blocking the drains during the dry period, and part of the problem is that people do not realise they’re blocked — so they need to make sure they keep them flushed all year round.”
“Dubai needs to adopt a better watershed management system in order to avert the recent flooding problems,” said Errol Edwards, general manager at Ajman Sewerage.
“It’s all about effective watershed management as a consequence of development, and how you capture the water.”
“It shouldn’t be too difficult. One way of capturing it in Dubai, particularly with all the lagoon developments, could be to interrupt some of the surface flow and direct it into the lagoons.
“Also, if you look at other places in the UAE like Al Ain, which have wadis in place to catch rain — maybe you could make these a part of infrastructure development in Dubai,”