Eco-friendly river bank protection technologies using coir geotextiles

摘要

This paper analyses the results of a field experiment conducted in Southern Kerala, India using coir geotextiles for riverbank protection. Coir geotextiles are reported to have applicability in conserving soil and moisture. Another reported advantage is its biodegradable nature, leaving no unwanted residues in ecosystem. Geotextiles cocolog has the ability to reduce water velocity by acting as semi- pervious media. This property of cocologs has prompted in using it for checking stream bank erosion as a temporary control material. Spurs constructed with cocologs at an interval of 20 meters at angle of 45°. Coconut logs were piled according to the pressure of the water current in the river. The cocologs were placed horizontally in between the coconut logs piled to the river bed. The number of cocologs varied from spurs to spurs depending on the condition and depth of riverbed; and the height of the spurs were maintained uniformly from the water level. The coir geotextiles of H2M6 (400 gsm) was placed connecting all the spurs 5 meters from the riverbank. In the context of sustainable eco-friendly riverbank management, this material can be used to strengthen the riverbank and protect them from erosion, which is cost effective and efficient compared to other conventional technologies. This technology not only prevent the riverbank erosion, but also helps in sediment the soil particles carried with the flood water along the river bank. It is further noted thatwithin a period of 14 months, natural vegetation was established on rear side of spurs predominant with reed and locally grown vegetation which consolidated the soil along the riverbank. After 30 months the spurs constructed with cocologs and coconut logs started biodegradation and by that time strong vegetation was established along river bank capable of arresting the erosion from bank completely.