A cost-effective method to protect the coastal regions from sea level rise. A case study: northern coasts of Egypt

Sea level rise resulting from climate change represents one of the major challenges for coastal regions, e.g., coastal erosion, submergence of shore cities and saltwater intrusion. This study presents a feasibility study of using a diaphragm wall (DW) to protect the northern coasts of Egypt from sea level rise. The study includes assessment of environmental and socio-economic impacts of the expected sea level rise. A finite element model is developed using the PLAXIS software and used to analyse the effectiveness of using DW in preventing the seepage of saltwater. The results show that the cost of constructing DW along the coast is about 1.0% of the expected losses due to sea level rise by 2100. For Alexandria city with 35 km of coastal line, the economic losses by 2100 is expected to be about $3.5 billion if no action is taken. However, the cost of constructing the DW along Alexandria coasts will be around $35.0 million which represent 1.0% of the expected losses. The total cost of constructing the diaphragm wall along the northern coast of Egypt is estimated to be $1.0 billion for 1,000 km length. This methodology can be applied to protect different coastal areas all over the world.