Nile Delta: Recent Geological Evolution and Human Impact

Abstract

Few countries in the world are as dependent on water from a single source as Egypt. The natural Nile cycle of flow and sediment discharge has been disrupted by human intervention, including closure of the High Aswan Dam; this intervention has resulted in a series of responses that now threaten the northern Nile delta. Erosion, salinization, and pollution are inducing a marked decline in agricultural productivity and loss of land and coastal lagoons at a time when the population is expanding exponentially. Geological analyses of radiocarbon-dated cores across the northern delta are used to interpret the interaction of sea-level changes, climatic oscillations, subsidence, and transport processes during the past 35,000 years. Recognition of long-term trends of these natural factors provides a basis to evaluate the profound impact of human activity and to assess future changes in the Nile delta ecosystem.

A global standard for monitoring coastal wetland vulnerability to accelerated sea-level rise

“…We plotted the locations of known RSET sites, based on a literature review, unpublished collaborations and personal communications. We then overlaid a map of the coastal regions hypothesized to have the world's most SLRvulnerable wetlands, defined (for mangroves 67 ) as those that were not macrotidal (that is, had <4 m tidal range) and were far from a large sediment source such as a delta (this definition excludes sites vulnerable for anthropogenic reasons, such as the Mississippi and Nile deltas, although anthropogenically induced subsidence is a significant threat 68,69 ). For temperate salt-marshes 70 we applied the same criteria, but excluded any regions that are experiencing tectonic uplift resulting from postglacial isostatic adjustments 71 or coseismic / interseismic uplift 72,73 .…”

Human-induced sedimentological changes in Manzala Lagoon, Nile Delta, Egypt

“…The rate of modern sediment accumulation is ~ 1.2 cm/year. This value is markedly higher (nearly double) than the long-term mean rate of accumulation (ranging from 0.5 to 0.7 cm/year) calculated for the past 7500 years in long core sections (Stanley and Warne 1993;Stanley and Goodfriend 1997). Accumulation until recently has been less than 1 cm/year, when taking into account sediment compaction of core sections.…”

“…As anthropogenic alteration of Manzala continues, this wetland will appear increasingly similar to the more modified wetlands, first like Idku and then Maryut. It is not expected that Manzala will reach the extreme situation of Abu Quir lagoon, once positioned southeast of Alexandria and then completely drained before the end of the last century (Warne and Stanley 1993). It is recalled that Egypt already uses almost 98% of its Nile water source, and it is evident that progressive elimination of Manzala as a natural reservoir has serious ramifications.…”

“…These serve as large, much-needed fresh to brackish water reservoirs anc major fish resources for Egypt (George 1972). The marsh and lagoon systems, of which only four remain in the delta (Maryut, Idku, BuruUus, Manzala), continue to be reduced in area and otherwise modified as a function of increased populafion pressures (Sestini 1989;Stanley and Warne 1993). Since the turn of the century, the margin configuration and hydrographie, floral, faunal, and other attributes of the delta wetlands, positioned near the Mediterranean coast (inset.…”

Holocene Lake Sediments as a Source of Building Material in Ancient Egypt; Archeometric Evidence from Wadi Tumilat (Nile Delta)

“…It is slightly carbonate only and belong to a gezira sand (Figs 5A, 6A) formed in the Late Pleistocene as a result of the Nile accumulation, most probably by a high-energy braided river (Stanley and Warne, 1993;Welc and Marks, 2014;Welc, 2016). Almost along the entire cross-section, this sand is overlain by a thick clay -the lake sediments that were formed in the Holocene (Stanley and Warne 1993;Welc and Marks, 2014;Welc, 2016). Clay sediments occurring in the northern, marginal part of the ancient lake are ash-grey to blue in colour and contain a significant amount of dispersed organic matter and calcium carbonate.…”