Vulnerability Assessment for Sea Level Rise Impacts on Coastal Systems of Gamasa Ras El Bar Area, Nile Delta, Egypt

Abstract

The objective of the current study was to assess the vulnerability of coastal systems to sea level rise (SLR) impacts in the Gamasa Ras El Bar area, which is one of the most vulnerable coastal areas in the Nile delta, Egypt. To achieve the study objective, a field campaign was carried out to investigate, measure and collect data. These data, as well as historical data, were analyzed to identify projected inundation areas, erosion and accretion rates, shoreline changes, wave climate and saltwater intrusion, as well as drainage infrastructure efficiency. The results of a 73-cm SLR, projected up to the end of current century in the study area, indicate the following. Inundation areas will be about 2.16% of the study area. Although the significant wave height increased by 3.1 cm per year from 1999 to 2010, the results are indicative and might be taken into consideration in future coastal management plans. The expected variation in groundwater heads due to sea level rise will lead to an increase in groundwater heads ranging from 0 to 0.5 m above the current level. The change expected in groundwater will lead to saltwater intrusion by 1 km landward. The analysis of our results showed that about 271 km2 (60%) of the area under study will be negatively affected by rising groundwater. This area is occupied by about 70% of the localities in the study area. The analysis of the projected groundwater level rise showed that it will increase the discharges of the sub-drainage system by about 10% of the current rates and less than 1.2% for the open system. It is concluded that the drainage system has the sub-capacity to host the expected increase in drainage discharges without any modifications of the cross-sectional area of most of the drains. In addition, the coastal groundwater aquifer was found to be the most vulnerable system in the study area.