Challenges and solutions galore with our 30 m deep silt curtain, delivered to Turkey for silt containment during the construction of a new oil refinery…

This year has undoubtedly been interesting – and challenging for Aquatic Engineering! We completed our longest ever silt curtain of 1.2 km, which was sent out to Turkmenistan. This was then swiftly followed by our deepest silt curtain which we deployed in the Aegean Sea in Turkey. It was easier said than done however; the manufacturing challenges and the delivery and installation logistics were probably the most difficult that we have ever encountered. Our specification and fabrication teams were outstanding, and drawing on knowledge built up over many years, we designed, constructed, delivered and installed a highly effective 30 metre deep silt curtain in budget and on schedule!

The job was completed for a company called Submarine Services and Maritime Activities, based in Istanbul, and the silt curtain was to protect a piece of coastline in Izmir, on the Aegean coast where a $ 3.2 billion oil refinery project, known as STAR Refinery, is underway. Environmental protection was to be at the heart of the contract, which is not usually a problem, however this project required the containment of suspended sediment from the seabed to the surface of the water; a physical barrier extending the entire drop of the water column! In addition, the seabed was not level and the sea state was impacted by prevailing northerly winds!

To put the pressure on still further, our Turkish contact then informed me that adjacent to the development zone, meadows of Posedonia oceanica and Axinella ssp were growing. These sea grasses provide habitat for many species and are protected by European legislation. Their protection was paramount and construction of the entire refinery would be held up if a solution was not found urgently. The clock was ticking! Was it possible to install a top to bottom silt curtain in 30m of water with an extremely rugged seabed, and then hold it in position for 3 years during the construction works? There was only one way to find out – I booked a flight to Turkey!


Protecting the blue Aegean Sea, the Aquatic Engineering 30m deep silt curtain is installed parallel to the cliffs, bottom left, in this image of the oil refinery

This representation offers some idea of the scale of the project, which was quite simply awe inspiring. Our floating silt curtain was to be installed parallel with the cliffs in the bottom left foreground. The construction project is delivering Turkey’s largest refinery, with an annual crude oil processing capacity of 10 million tons. The project aims to relieve Turkey’s petrochemical sector of its dependence on imports, and it is projected to become operational in 2017…assuming we could protect the Posedonia oceanica sea grass. No pressure!

Once in Turkey we spent two days on site, analysing the physical restrictions of the site, and also enjoying this most beautiful of countries. We completed a design concept and gave the go ahead to the factory back home. Other than for nightmare bureaucracy (more of this later), I found Turkish Companies to be incredibly professional and their Health and Safety second to none.

This was certainly going to be the deepest full depth silt curtain fabricated in the UK and I’m unaware of anything similar being manufactured and deployed anywhere else. We worked flat out with extra shifts, and fabricated it in our Isle of Wight factory in just 6 days!. We then delivered it to Southampton, loaded it onto a lorry and transported it to Turkey by road in a further 11 days! Quite an achievement for all concerned.


It was no mean feat loading this 30m deep silt curtain onto the lorry for despatch!

We flew over to Turkey to meet the lorry on its arrival. After many hours of negotiations in 40 degree heat we unloaded the silt barrier into a bonded warehouse just 3 miles from site. It then proceeded to sit there for 6 weeks, leaving us no choice but to return to the UK in the interim. Customs clearance was as much a challenge as the production! Everyone smiles and is extremely helpful and will say yes, but they are themselves subject to multiple layers of management and signing off procedures from above. A lesson learnt!

We finally returned to site at the end of July and teamed up with an experienced Turkish dive company for the installation. Efficient deployment would be crucial. As well as a silt curtain of mammoth proportions, we had 32 tonnes of anchors to manoeuvre. The extreme depths also meant that the divers were restricted to a maximum of 30 minutes underwater.

We had been told there were no currents – however after 24hrs at sea and only one anchor deployed, it became clear that the curtain was under immense pressure from subsurface currents! It was time for a rethink and by the end of the following day, credit to a phenomenally talented team, the curtain had been successfully deployed.


Glyn and the deployment team at work installing our 30m deep silt curtain. The colossal silt curtain needed the colossal anchors that can be seen on deck!

So this year has seen us extend our product portfolio to include extreme depths and lengths for our silt curtains, and we have also substantially increased our knowledge of Turkey and Turkmenistan! We hadn’t know it at the time but the two projects were linked in more ways than one.   It transpired that our Turkish friends at the oil refinery had also worked on the site in Turkmenbashi where we had earlier sent 2 x 1.2km silt barriers… Once back in the UK I was invited to a dinner at a friend’s house, completely unrelated to Aquatic Engineering, only to find that the lady next to me was a senior engineer and her last project was to design the pipeline connecting Turkmenistan to Turkey. Small world!

Glyn Onione – Senior Technical Consultant at Aquatic Engineering

Have a question about silt curtains? Aquatic Engineering have the answers. Email or phone us on 01983 616668