Geotextile tubes to protect coasts

ALAPPUZHA: The irrigation wing under the water resources department  is  working on a pilot project using geosystems tubes in place of the conventional method of seawalls to  save  the coast from the high sea.

This system, which is being implanted in a 100- metre area in Neerkunnam coast here, was taken up because of the unavailability of sizable flints that rocky seawall required.

According to  Anilkumar Gopinath, vice-president, Maccaferri Environmental Solutions Pvt ltd (India), which is undertaking the project,  it was for the first time that  geotextile tubes that come  under geotextiles containment systems called geosystems  was being tried to replace the conventional method of seawall construction. 

‘Geotextile tubes are made of high-strength geosynthetic fabrics that allow the water to flow through pores retaining the filled up materials that is sand. The pilot project will cover at least 100 metres  along the Madhavamukku coast and half  the work has already been done,” he says.

The area was chosen by the irrigation department  considering the high tide in the area. The traditional seawall constructed earlier and subsequent maintenance works undertaken along the two-km stretch of the Madhavamukku coast in Ambalapuzha south panchayat have been ineffective and many parts have been already swept away.

“The advantage of this system is the energy of the wave gets reduced as it hits the sand-filled geosystems while rock structure is unable to suppress higher energy scouring the toe. It takes around 5 hours to lay a single tube of 20m length and 1.5m height and it’s much faster than the rock structures works. As on date 40m of seawall ( 2 bottom tube + one top tube) using geosystems have been done and the remaining work will be finished in 10 days.

Ponniah Chandran, techical advisor, said that geotextile tubes of length 20m and diameter 3m was made of a large cover of polyester fabric  and a shroud layer of  polypropylene fabric. “After the bags are filled with sand the tubes are covered with the balance excavated material to prevent UV ray effect and vandalism,” he says

Meanwhile, local people have said that the new project will be tested  in June –July.  “If it survives sea erosion season, it would be a great relief for us,” they say.