Geo-spatial mapping and simulation of the sea level rise influence on groundwater head and upward land subsidence at the Rosetta coastal zone, Nile Delta, Egypt

The coastal zone has been experiencing population growth and incomparable developments that are in discordance with the dynamic nature of the coastal system. The present study focused on the Groundwater Head (GWH) changes and upward land subsidence as a result of Sea Level Rise (SLR). Consequently, the numerical model of SEAWAT is applied to the Nile Delta Aquifer (NDA) at the outlet of the Nile Rosetta branch to simulate the (GWH) for the current situation and the future scenarios of SLR. It was estimated as 5.67, 14.51 and 26.71 cm at the years 2020, 2040 and 2060, respectively. The resulted of GWH are ranged between 0 to 0.40, 0 to 0.45 and 0 to 0.55 cm at the years 2020, 2040 and 2060 respectively. The GWH were then used to predict the future upward land subsidence by applying high least square linear regression analysis. An inverse relationship was found between the GWH and the upward land subsidence with correlation coefficients (r2 = 0.87). Where the hydraulic head increased as a result of sea level rise the rate of upward land subsidence decreased through the years 2020, 2040 and 2060 respectively. The geospatial mapping of the upward land subsidence shows a general increase to the northern part at the Rosetta Promontory, which has the highest thickness and accumulation rates of the Holocene deposits.