Creating an Arabian Venice
Waterways are becoming a desirable feature in Middle East developments, but how do you keep the water flowing in the desert? MEP Middle East finds out how one project is being created.
In an area of the world where desert is the predominant landscape, the desire for a waterfront view is understandable.
A limited coastline has not stopped developers offering this luxury to their clients and developments like the Jumeirah Palm and The World have created new opportunities to increase the number of properties with sea views.
But inland also, the number of developments including waterways in their plans is increasing, which brings added challenges: just how do you maintain water levels and clarity in hot and humid conditions?
Dubai’s City of Arabia is one such project currently underway. Here a 10km waterway or ‘Wadi Walk’ will be constructed in two phases.
Bill Muir, Ilyas & Mustafa Galadari Group senior project manager for City of Arabia explains: “We are creating an enclosed canal system; phase one of the scheme will create a 7km waterway, in phase two an extra 3km will be added.”
The waterway is the centrepiece of the development and will flow past shops, restaurants, apartments and hotels.
It will turn into scenic water attractions at various points, in particular when it flows inside the North Portal of the development’s Mall of Arabia, where a waterfall pours into the main waterway.
Electrically powered abra water taxi’s will ferry residents and visitors around the canals.
The wadi will be constructed from reinforced concrete with a waterproof pvc lining membrane.
This will be topped by a layer of Shotcrete to give a natural effect.
The water will be 1m deep in the waterways, while the overall basin depth will reach 1.5m.
The width of the waterway varies from 8-15m and stretches to around 30m wide at junctions.
The total water volume for the waterways will be around 130,000m3; 52,000m3 for phase one and 78,000m3 for phase two.
“One of the big issues with the project is actually filling [the waterways] up to start with,” stresses Muir.
“We will have to tanker in clean water, which has big logistics issues and will take two to three weeks to do.”
The reason for choosing tankered water over mains supplies is down to timing.
“The mains water is not available when it will be needed and it may take longer also to fill due to the capacity [of the mains],” Muir adds.
The canal water will be at ambient temperature, which in the high temperatures of Dubai creates secondary issues.
“One big issue is evaporation,” explains Muir.
“We will have to top up the levels.”
Evaporation is estimated at 0.35-0.50% of the surface area per day, hence 300-500m3.
The water level will be maintained by a combination of treated sewage effluent water (TSE) and freshwater supply.
Another area where the system needs particular attention is where it enters the shopping mall.
The difference in temperature of the water in the canals and that in the waterfall pool in the mall could cause condensation if not addressed.
“We’ve got a sophisticated system where we must ensure the water coming into the mall is only at 20-22ºC,” explains Muir.
Consultant engineer WSP Mechanical is designing a solution whereby the water will be pumped via underground insulated pipes, so that it will cool to the same temperature as the waterfall pool before it enters the mall.
The final factor to be considered for the waterway is its cleanliness.
“We are having almost potable water quality to avoid discolouration of the waterways, smells and we want it to be bacteria-free,” explains Muir.
”This is a central feature so it is essential to have a nice environment.
Also, if you have lots of people using the waterways, the last thing we want is for them to be getting ill after running their hands through the water,” he stresses.
Canal systems require careful treatment to keep the water clean.
The large surface areas mean that frequent filtration is necessary by a system that can remove large and small particles.
There will be 11 water treatment plants located throughout, including one dedicated to water in the mall’s North Portal.
The consultant and contractor for the water treatment and measurement system for the project is Danish firm Aqua-Teknik.
The walter filtration system that Aqua-Technik plans to install will utilise the latest technologies in water treatment.
“This is the largest filtration system in the world,” states Muir.
“There is a variety of treatments included such as filtration, dozing and ozone treatment.”
Installation of services will follow the same linear development as the project buildings, avoiding the need to run them below the waterways.
The infrastructure for the mall is currently being installed and MEP contractors are expected to be appointed within the next month.
With projects such as this set to increase in the region, the products and solutions needed to create and maintain them will be in big demand, providing opportunities for all those in the market.
"Canal systems need careful treatment to keep the water clean; large surface areas mean frequent filtration is needed"