Exploring new ground

Gerald Schouest is concerned about coastline loss in his home of Terrebonne, Louisiana, USA

Gerald Schouest is 69 years old. He has always lived in Terrebonne, Louisiana, USA, like his parents and native American grandparents. “Hunting for fish and waterfowl is a way of life,” says Gerald. “Many people live off the land, but now this is under threat.”

Terrebonne was formed from sediment carried by the Mississippi river. The land is soft and the sea takes it away with ease. No fresh sediment replaces it since local authorities built walls to strengthen the riverbanks. Homes are growing more exposed to the hurricanes which regularly hit the coast. Water in the marshes is increasingly salty as seawater runs in, risking the loss of fish, crab oysters and shrimp – along with the income they provide.

To help restore the land, the local community is trialling a new scheme using mats made from recycled plastic bottles. Shaped into rectangular frames, these hold soil and plants.

Floating islands

Gerald is a member of the Terrebonne Parish Coastal Zone Management Committee. He and fellow committee member Ed Landgraf, who also works as a public awareness representative for Shell operations in the Gulf of Mexico, heard about floating mats used in lakes and for islands on golf courses developed by Martin Ecosystems. The pair saw potential for using them in the sea to protect Terrebonne from erosion.

Volunteers from Shell US plant native grasses in floating mats to help protect the shore

They helped raise money through public and private funds – with Shell Oil Company as the main contributor – to build a strip of plastic mats stretching over 450 metres (1,500 feet).

Each one is around 1.5 m (5 ft) by 2.5 m (8 ft) and 20 cm (8 inches) thick, containing foam to keep it afloat. Volunteers – including many from Shell US – helped plant native grasses into holes drilled in the mats. Stainless steel cables secure the mats to the seabed a short distance from the shore.

The cables are designed to steady the mats against waves of up to 1.2 m (4 ft) high. Over time the volunteers hope the plants will grow and join up with those on land.

“This is the first time the mats have been tested in open water,” says Gerald. “So we have to wait and see if they succeed.”

More solid foundations

So far the signs are good. Two months after the mats were installed the plants had almost doubled in height and sent roots towards the seabed. “I have seen birds nesting in the new land,” says Gerald. “And there are droppings from racoons and otters.”

Gerald and Ed are already looking at using the same approach in another nearby community. “The floating islands alone won’t save the coast,” says Gerald. “But we need to use all the measures we can to stop our community from disappearing into the sea.”