A Case Study on Performance of Jia Bharali River Bank Protection Measure Using Geotextile Bags

Abstract

River bank erosion is one of the major natural disasters being faced by the state of Assam, located in the North-eastern part of India. With the increasing popularity of geotextile materials in construction industry several pilot projects to control bank erosion of major rivers of Assam have recently been executed with the application of geotextile bags, geotextile tubes. But very little scientific study on the post-construction performance of these works is available. In this paper the findings of a study on the post construction performance of one of these recently completed bank protection works is presented. In order to ascertain the erodibility of the bank soil characterisation of geotechnical properties of the bank soil is carried out. The bore log obtained by adopting a simplified method of boring suitable for this investigation is presented along with detailed laboratory test results and analysis. The change in river flow pattern near the bank after installation of the bank protection work and the resultant siltation is studied in this work. In order to predict progressive development of sand bar due to the induced siltation during the first 1 year after installation of the protection work the siltation area is surveyed and the contours are prepared. The resultant flow pattern is reasonably determined from the siltation area contours. Satellite images of the study area for a period of 3 years after installation of the protection work are analysed and presented before arriving at a final conclusion on the performance of the protection measure.