Land and groundwater resources in the Egypt’s nile valley, delta, and its fringes

Abstract

The current Egyptian situation is framed by land and water scarcity, which are under severe pressure. The Nile Delta is one of the most densely populated deltas in the world. Soil and water resources are at the center of sustainable development and are critical for socio-economic development. Nile Delta branches gain water from the aquifer in some reaches and lose water to the aquifer in other reaches. The flow directions between groundwater and surface water can change seasonally with variations of the water table level with respect to the level in nearby waterways. Available data on the evolution of the salinity of groundwater in the Delta indicate that the construction of the High Aswan dam resulted in a shift of salinity isolines towards the seashore, and that current pumping rates have not yet critically affected this balance. Possible localized over-pumping, however, results in “up-coning” of salinity from deeper layers. Contamination of groundwater by agriculture and more prominently by seepage from domestic and industrial effluents had already attained worrying levels. This may jeopardize the quality of the Nile Delta aquifer in the end. The increasing use of groundwater for irrigation poses a serious threat to food security and could lead to unaffordable prices of staple foods. Therefore, groundwater overuse rising could hit food prices. Aquifer depletion can induce significant environmental degradation, such as land subsidence and seawater intrusion. The amount of non-renewable groundwater used for irrigation was doubled in Nile Valley and Delta. The annual groundwater abstraction in the Nile aquifer system and fringes is about 4.6 billion m3. Another 0.5 billion m3 is abstracted from the desert aquifers and the coastal areas. Groundwater abstraction is expected to increase to 11.4 billion m3. Model output revealed that groundwater recharge has not changed significantly over time, while pumping has. Because of these trends, groundwater was estimated to be in a deficit of approximately 24 billion m3 (±15%) in year 2011, compared to year 1957. Most of the Nile Delta soils are recent alluvial soils. The soils generally have a light to heavy clay texture. The clay content varies from 40% in the south to nearly 70% in the north. The soils located near the north coast and lakes are of marine and alluvial deposits. Close to the desert fringe on both sides of the Delta occurs the desert sandy plains, which are flat to undulating topography. The soils of the coastal plains and beaches are sandy with some low to medium longitudinal sand dunes. The salinity problem becomes more severe in the Delta as we approach the seacoast and lakes, due to the effect of the shallow, saline groundwater and the brackish water intrusion from the sea and lake. The old and young terraces of both western and eastern sides of the Nile Delta are of alluvial origin and non-uniform in nature. Most of the soils are originated from the ancient Nile sediments, which are mostly derived from igneous and metamorphic rocks of the Abyssinian Plateau. The soils are alluvial deposits of the Nile Delta (Qatabeya) and valley (Qena), swamps and fluviomarine-lacustrine deposits (El-Manzala), beach sands (Edku). The old alluvial soil is more developed than other soils.