'Geobags' could protect Arctic from rising seas

A team of French and Norwegian researchers have developed an environmentally friendly, low-cost way to protect Arctic regions from coastal erosion and rising seas: so-called geosynthetic bags made of woven polymers and filled with whatever local, low-grade soil is available.

Geosynthetic bags have been successfully used for more than 40 years in temperate climates, but had not previously been tested in sub-zero conditions. So TenCate Geosynthetics France, a producer of geosynthetic materials for civil engineering projects, decided to find out whether it could develop a product that would work in very cold conditions.

“Our northern European sales offices asked us to develop suitable materials for cold regions where the temperature is rarely above zero,” said Olivier Artières, TenCate’s innovation project manager and senior expert. “They face specific problems such as the thawing and freezing cycles of water that make the construction of infrastructures like roads and jetties difficult.”

He continued, “Following a discussion with colleagues at Norway’s SINTEF Research Institute, we decided to hold a brainstorming session with local users to gain a better understanding of their needs and the kind of solution they were looking for. They told us that constructing embankments under water to create dykes and breakwaters was a major problem, and protecting against coastal erosion. This was particularly so in areas such as Svalbard, where traditional solutions are too expensive or don’t comply with strict environmental regulations, and which also lack suitable geological material for building protective infrastructures.”

With the support of EUREKA and the Norwegian-French Foundation, the project team set about developing envelopes made with textiles comprising different structures (woven, non-woven and knitted) and different types of polymers. The team also worked to determine the optimum shape and size of geosynthetic bags to be used in Arctic conditions.

“The cold makes it extremely difficult to work in the Arctic,” said Artières, “so it was a matter of finding the best compromise between a solution that works well and is also easy to install, as well as being inexpensive and environmentally friendly.”

Geobags made from different types of textile were installed along a 100-metre stretch of coastline near a mining camp on Svalbard operated by project partner Store Norske Spitsbergen Grubekompani (SNSG). Over three winters, their response was monitored to the cold, ice movement, currents, abrasion and other stresses characteristic of the area. The results were so good that SNSG used the bags to repair a damaged quay wall in the local harbour instead of locally available rocks.

The new cold-climate geosynthetic bags are expected to be launched on the market in early 2010.

With climate change models predicting that the northwestern coasts of Canada and Alaska will be ice-free by 2020, and an estimated 25 per cent of the world’s undiscovered oil and gas resources located in the Arctic, the market potential for the “Geobags” is considerable, as all new operations will require land-based infrastructures in need of protection. Several new Russian fields are also currently planned in the Barents and Pechora seas.

Given the ecologically fragile nature of arctic regions, Geobags have another significant advantage, said Artières.

“Geobag infrastructures are reversible — if they are no longer required, they can simply be emptied and the place left exactly as it was before construction,” he said.