Engineering

Palm Jumeirah was Van Oord’s very first mega-project in Dubai. Better known as Palm Island or simply 'The Palm', it is an artificial island in the shape of a palm tree consisting of 700 ha of new land. Van Oord used approximately 110,000,000 m3 of sand to create the island. It also constructed a circular breakwater of around 11 km in length to protect it. The project was completed in 2003. How did we tackle it?

How do you create an island right in the sea?

You start by drawing up a thorough risk analysis.

There are in fact two categories of risk (as far as technology goes):

- a slow and progressive process that builds up gradually to alarming proportions, for example the wrong production estimates or feasibility;

- sudden events, such as a storm that destroys the new land in a matter of hours. It is difficult to predict and calculate the chance of such events and their possible consequences.

The second category of risk was a point of special concern during the run-up to the Palm Island project, in particular with respect to the expected sand transport and possible related losses in various strategies and scenarios. The ultimate aim was to develop the most favourable strategy in technical and economic terms.

Other factors were the natural conditions, such as depth of water, wave action, tides and currents. Our long-term wave climate calculations showed us that the Shamal, the northwesterly wind that blows up storms in the Persian Gulf, occurs a number of times each month. In winter, the waves reach from 2 to 3 m high, rising to 3.5 m in one or two of the bigger storms. Waves of 4.5 to 5 m were likely once every hundred years. To determine the influence of the waves on the project, we calculated the monthly wave climate within our operating area at approximately 50 locations, taking this as a function of the project's progress. We did this using the wave propagation model SWAN.

We came to the conclusion that it would be an enormous risk to build above the water line before the breakwater was in place. We therefore explored what would happen if we constructed the island under water, up to about -4 m or -6 m. In the simulation, the Palm would lie -4 or -6 m below the surface. In our model, the losses increased exponentially when the Palm was built up any higher. We noticed, however, that the effects were reasonably limited around -6 m and -5 m.

All this resulted in the following strategy:

Deposit the sand unprotected up to a depth of -5 m (that was the first winter). Our schedule allowed for this, because we still had to deposit a minimum number of m3 during that period.

Build corridors to avoid becoming locked in.

Deposit the sand up to 3 m while keeping pace with the progress of the breakwater.

We naturally took a good look at the logistics so that we could dump as much as possible (the fastest and cheapest method) and leave enough space open for rainbowing and corridors, so that the vessels would not have to take unnecessary detours.

Finish constructing the island after the breakwater is done.