Importance of Location & Alignment of Geotextile Tubes for the Coastal Protection Measures

The placement of the geotextile tubes plays a functional role in the performance of the overall protection scheme. The placement path of geotextile tubes is the crucial decision for the designers. The geotextile tubes are widely used as a reef structure, well below the Mean Sea Level. The requirement of the beach width is the main criterion to decide crest level of the nearshore reef structure. In case of beach nourishment project the un-segmented row of tubes placed below MSL can be used as a dual purpose. Firstly, it acts as an offshore reef & helps the trapping of sediments during the downrush and secondly, as a barrier for the offshore movement of the existing nourished sand. The recurring periodic expenditure of the beach nourishment would also decreases after the beach stabilization within 2-3 years. Based on onshore-offshore movement or alongshore littoral drift, the solutions in the form of parallel offshore reef or perpendicular groyne field with sand-filled geotextile tubes are decided. The importance of site specific design with geotextile tubes in accordance with the needs & site conditions etc. are discussed in details with few case studies.