The River Nile: Evolution and Environment

Abstract

The Nile Basin drains about one tenth of the African continent and contains the longest river channel system in the world (>6500 km). The evolution of the modern drainage network and its fluvial geomorphology reflect both long-term tectonic and volcanic processes and associated changes in erosion and sedimentation, in addition to sea level changes (Said, 1981) and major shifts in both climate and vegetation during the Quaternary (Williams and Faure, 1980;Talbot and Williams, 2009;Woodward et al. 2015a;Williams 2019). In the Holocene, abrupt climate shifts, human impacts in the form of land use change over the last few millennia, and large dam construction over the last hundred years or so, have had major catchment-wide impacts on the hydrology and sediment budget of the River Nile. The river basin extends over 35° of latitude (4° S to 31° N) incorporating a great diversity of climates, river regimes, biomes and terrainsincluding the Equatorial lakes plateau of the White Nile headwaters, the semi-arid volcanic uplands of Ethiopia, the Sahara Desert, and the vast delta complex at the Eastern Mediterranean Sea. The Nile is also the world's longest exotic riverit flows for almost 2700 km without any significant perennial tributary inputs. The true desert Nile begins at Khartoum (15° 37′ N 32° 33′ E) on the Gezira Plain where the Blue and White Nile converge (Figure 14.1). These two systems, and the Atbara to the north, are large rivers in their own right with distinctive fluvial landscapes and flow regimes. The Nile has a

Image Segmentation of the Sudd Wetlands in South Sudan for Environmental Analytics by GRASS GIS Scripts

“…The average temperature is 18.5 • C, while the precipitation is 320 mm. High evaporation over the Sudd marshes results in strong effects on the regional water cycle of the Nile hydrology, which is amplified to a large extent by the Sudd wetland area: it is the largest wetland area existing in the world and the largest freshwater swamp region in the Nile Basin [96]. The environmental measures were undertaken to decrease evaporation from the Sudd by constructing Jonglei channels [97].…”

Three thousand years of river channel engineering in the Nile Valley

“…Research on the human modification of channels along the main Nile has primarily focused on the impacts of dam and canal construction in the modern era (e.g., Bunbury et al, 2023; Stanley, 1996; Woodward et al, 2022) or on ancient canalisation and harbour infrastructure (e.g., Boraik et al, 2017; Quirke, 2009). To date, river groynes in the Nile Valley have been subject only to localised examinations (e.g., Tahir & Sadig 2014; Vercoutter, 1966; Wolf & Gabriel, 2008) and, to our knowledge, none have been independently dated.…”