Assessment of Changing the Abstraction and Recharge Rates on the Land Subsidence in the Nile Delta, Egypt

The majority of residential, agricultural, and industrial areas are situated on cohesive soil in the Nile Delta, Egypt. Excessive pumping from the Nile Delta aquifer to meet the increasing demands for water could lead to aquifer system compaction and land subsidence. Land subsidence endangers infrastructure such as buildings, bridges, canals, and roads, as well as deteriorating lands and agricultural resources. The objective of this research is to investigate the land subsidence and predict the future behavior of the middle Nile Delta. The study goals are met by using a numerical model (MODFLOW) to simulate groundwater flow and an analytical solution to calculate land subsidence conditions. In this study, three scenarios are considered including; decreasing aquifer recharge, increasing abstraction and combination of the two. The results reveal that decreasing recharge by 94.4%, 88.8%, and 83.2% led to 30-, 60-, and 90-mm land subsidence, respectively, while increasing abstraction by 146%, 193%, and 233% led to land subsidence by 190, 380, and 560 mm, respectively, in the Nile delta. However, the combination of the two scenarios led to 220-, 440-, and 650-mm land subsidence. According to the results the future land subsidence due to over pumping from the Nile Delta should be considered in the future development plans of the country which intend to increase the abstraction from the Nile Delta aquifer. Increasing abstraction could increase the land subsidence that may cause many damages in different properties.