Utilization of Geotextile in Rubble Mound Breakwater for Coastal Protection Lamanto T. Somervell Research Scholar Department of Civil Engineering, National Institute of Technology, Calicut lamanto@gmail.com Greeshma Nizy Eujine Research Scholar Department of Civil Engineering, National Institute of Technology, Calicut nizy_123@yahoo.com Jyothis Thomas Professor Department of Civil Engineering, College of Engineering Trivandrum, jyothis_thomas@yahoo.co.in ABSTRACT Rubble mound breakwaters, seawalls, and groins are widely used around the world for the construction of artificial harbors and for shore protection works. These methods are sometimes expensive, ineffective and inefficient and are not eco-friendly. Fabricated geosynthetic materials have gained popularity in recent years because of their simplicity in placement, cost effectiveness and environmental aspects. In the present work physical model studies were conducted to study the efficiency of sub-aerial detached rubble mound breakwaters with geotextile filter media (coir fiber mat) below the armor layer as a wave attenuator in three different submergence conditions. Data acquisition system with 10 sensors was used to measure the wave attenuation. A stretch of 1.3 km along Poonthura – Valiyathura was selected as the study area. The efficiency of the breakwater as a shore protection measure was determined based on the percentage of energy dissipated by the breakwater and the change caused in the beach profile. The rubble mound breakwater with geotextile fiber media below the armor layer in zero-submerged condition was found to be the best of three types of breakwaters tested as it dissipated the maximum amount of wave energy. KEYWORDS: shore protection; coastal erosion; geotextile breakwater; wave energy; breakwater I NTRODUCTI ON Coastal erosion is due to the action of wave energy in the coastal zone. This leads to loss of valuable beaches, agricultural lands, damage to coastal vegetation and stoppage of fishing activities. To minimize the wave energy engineers have designed many structures like seawalls, rubble mound breakwater, groins and detached breakwaters which can provide direct or indirect protection of the coast. - 6997 -