Flood-Hit Assam Plans To Curb Soil Erosion Using Geo Tubes — What Is It And How It Works

Assam has successfully employed geo tubes to protect dams from flooding. Geotextile tubes are woven bags filled with sand or slurry that act as erosion barriers.

Geo Tube

Buoyed by the successful implementation of geo tubes in several coastal areas in India, the Assam government has used these large bags-- filled with sand or slurry-- for the first time for dam protection work during floods. 

According to Assam's Water Resources Minister Pijush Hazarika, construction of 7.2 km long geo mega tube on both sides of the river will protect erosion during flooding.

The geo mega tube has been constructed at a cost of Rs 25 crore under Rural Infrastructure Development Fund (RIDF).

Assam's flood situation remained critical on Tuesday, with over 6.5 lakh people reeling from the second wave of flooding, as the Indian Air Force (IAF) rescued 13 stranded fishermen from the severely-hit Dibrugarh district.

What Are Geo Tubes?

Geotextile tubes or geo tubes are engineered tube-like sacks that are filled with sand and slurry. They are made from high-strength woven or non-woven geotextile fabric, which is typically made from polypropylene or polyester materials that can withstand the forces of wind, waves, and storms.

Sometimes, they are covered with gabions – a wire box filled with small rocks. Geo tubes are usually constructed between the high- and low-tide lines. They allow water to pass through by reducing the pressure on the wall to prevent damage and erosion. 

These tubes are placed in a trench along the shoreline or riverbank and then covered with more sand or soil to create a natural-looking barrier by blending in with the surrounding landscape.

Geo tubes are also cost-effective due to their sustainability. Over time, when the sand or soil inside the tubes is settled or washed away, they can be easily refilled with additional material. 

Purpose of Installing Geo Tubes

Geo tubes are used as a reliable solution for a wide range of challenges, including erosion control, dewatering, sludge management, land reclamation, and shoreline stabilization.

They have proven to be highly effective in various applications, including coastal protection and land reclamation. 

India is already using geo tubes in various coastal areas including one in Uppada, a village in Andhra Pradesh’s East Godavari district, and another in Pentha, a village in Odisha's Kendrapara. In 2016, Geo-textile technology was used for the first time to repair damaged parts of National Highway 08 (NH08) (earlier NH44) in Assam's Karimganj district.

The Kerala government has also implemented the first phase of the Geotube Offshore Breakwater Coastal Protection Project at Poonthura and has decided to extend the project to another 700 m from Poonthura Church to Cheriya Muttam.

The Uttar Pradesh government is also installing this system in various places in the state to protect the Sangam noze from erosion. 

Challenges in installing Geo Tubes

Geo Tubes can collapse, leaving a gigantic void along the shoreline which can be dangerous. Over time, they can also get separated from the shoreline and begin floating in the middle of the waterbody. The system is also not very effective in uneven terrains, especially in mountains, as the flow of water is difficult to manage due to gravity. 

Moreover, sod does not grow on top of geo tubes so the dirt underneath gradually washes out, leaving ugly, exposed tubes on your shoreline.