Sea grass project elevates case for the environment

The environment isn’t usually the first thought in construction plans. But, as Shaun Lenehan, senior environmental engineer at Nakheel, explains, the sea grass research on the Palm islands is changing the way that offshore projects are designed.

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By  Zoe Naylor Published  May 13, 2006

|~|121int200.gif|~|According to Lenehan, EIAs are forcing developers to consider and compensate for any environmental impact that a project may have.|~|What is the background of the sea grass project?

Before the Palm Jumeirah was built, a survey was carried out which revealed there was very little sign of life there. But now there are abundant grass colonies carpeting the floor of the seabed.

It turns out that when you reclaim a landmass there is a lot of suspended sediment within the water column that settles out. You then get a silty layer on the sea floor that is a perfect medium for growing sea grass — it is high in nutrient growths and the configuration of our islands provides a very sheltered environment for the sea grasses to grow.

What are the benefits of sea grass growing in this environment?

It can increase water quality because the sea grass is able to consolidate the sediment on the sea floor with its roots. It also provides a nursery habitat for young fish.

There were some concerns with the turbidity [cloudiness] of the water, which can preclude light getting to the roots of the sea grass. Initially we thought that the grasses wouldn’t grow at that depth [3m to 9m] — especially after a Shamal [wind] — but it turns out we have sea grass all around.

Now that sea grass has been found growing at the Palm Jumeirah, what is the next step?

We are expecting to find the same pattern — that sea grasses will propagate by themselves at the Palm Jebel Ali. We therefore plan to get out to the Palm Jebel Ali when reclamation work is completed so we can start surveying the channels between the fronds.

Similarly we expect to find sea grasses in the shallow waters of the World development, and on the Palm Deira once the reclamation is finished. This adds up to hectares and hectares of sea grass wherever the water is calm.

What is Taisei’s involvement with the project?

When we found we had sea grass on the Palm Jumeirah, Taisei approached us offering assistance with the sea grass transplantation process. We’re very keen to assist in research that could be taken across the Gulf and across the world, and it’s a contribution that Nakheel is making as a patron of R&D within the UAE.

What stage is the project currently at?

Firstly, in the areas where we know there is sea grass, we’re putting down coconut fibre mats and anchoring them to the sea floor adjacent to existing sea grass beds. The hope is that the coconut fibre mats will be colonised by the grasses and we’ll be able to move them to areas where there are no sea grasses — creating a source of sea grass material that will colonise a new area.

We have now established some of the mats at secret locations along the Dubai coastline. This initial phase involves studying them to check not just if anything grows on the mats, but also to look at the type of environment in which they’re growing. The mats are put down at a depth of around 3m or 4m and will be monitored once a month for a year.

We’ve also done some direct transplant techniques where we’ve cut sods of sea grass and moved them into other areas nearby and to similar habitats to see whether the local species of sea grasses can tolerate direct transplantation.

Is this the first time that such a project has been carried out?

It’s not the first time in principal that sea grasses have been transplanted — Taisei has done some similar work in Japan with a similar species — but this technique is probably a first for the Gulf.

What provided the impetus for such a project, given this is not a region readily associated with environmental awareness?

Construction actually triggers a lot of this research because developers are required to compensate for any environmental impact.

If you go to any of the development shows that Dubai hosts you will see so many reclamation projects all around the Gulf and the Middle East, that there probably will be (and should be) a demand for ways to protect the environment.

These sea grass mats are one solution — what was once a very empty part of the sea floor now has quite a rich biodiversity.

What steps does Nahkeel take to ensure that the waters around Dubai are protected?

For all our projects we carry out EIA’s (Environmental Impact Assessments). These are a government requirement and a banking requirement for investment money, as well as a design requirement.

For example, the two major holes in the crescent of the Palm Jumeriah were the result of this environmental phase. At a great loss to real estate (and at a great expense) we cut the holes to ensure we had the best water quality inside the Palm.
Could the sea grass technology be used in other offshore projects around the region?

The stresses due to the salinity and summer temperatures may be more than the transplanted sea grasses can cope with, so there may also be seasonal factors to take into consideration. But with some tweaking, I’m sure the processes we came up with could be applicable to other projects in the region.||**||

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