Main Nile Research Articles

The implications of further reservoir development on the Blue Nile in Ethiopia: trade-offs between hydropower, irrigation and transboundary water security

Abstract We evaluate the implications for Ethiopia and Egypt of two dams that could be built upstream of the Grand Ethiopian Renaissance Dam (GERD), in combination with hypothetical Ethiopian irrigation schemes upstream of these Blue Nile hydropower facilities. Two new dams could increase average annual hydropower on the Blue Nile River from Lake Tana to Khartoum and the Main Nile River from Khartoum to Aswan by almost 50% (30.2 TWh yr−1 to 44.7 TWh yr−1). A system-wide analysis of the expected financial benefits of various development scenarios reveals little financial justification for substantial irrigation withdrawals upstream of the GERD. Withdrawing 5 billion cubic meters annually upstream of the GERD without additional hydropower development would reduce total average annual hydropower generation on the Blue and Main Nile River by 10.9% (3.3 TWh yr−1). If two new dams were constructed upstream of the GERD, withdrawing this volume would cause a 15.2% (6.8 TWh yr−1) reduction. 1 and 5 bcm yr−1 of withdrawals upstream of the three dams would also affect water supply downstream, reducing average annual outflow from Sudan’s Merowe Reservoir by 1.1% (0.7 bcm yr−1) and 6.2% (4.1 bcm yr−1), respectively, and by <1% (0.2 bcm yr−1) and 3.3% (1.8 bcm yr−1) at Egypt’s High Aswan Dam (HAD) Reservoir, respectively. Whilst the annual probability of the HAD storage falling below 60 bcm and invoking its current drought management policy is estimated to currently be 0.085, these two scenarios of upstream withdrawals would increase that annual probability to 0.111 and 0.452 respectively.

Historical climate impact attribution of changes in river flow and sediment loads at selected gauging stations in the Nile basin

The Nile basin is the second largest basin in Africa and one of the regions experiencing high climatic diversity with variability of precipitation and deteriorating water resources. As climate change is affecting most of the hydroclimatic variables across the world, this study assesses whether historical changes in river flow and sediment loads at selected gauges in the Nile basin can be attributed to climate change. An impact attribution approach is employed by constraining a process-based model with a set of factual and counterfactual climate forcing data for 69 years (1951–2019), from the impact attribution setup of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3a). To quantify the role of climate change, we use the non-parametric Mann-Kendall test to identify trends and calculate the differences in long-term mean annual river flow and sediment load simulations between a model setup using factual and counterfactual climate forcing data. Results for selected river stations in the Lake Victoria basin show reasonable evidence of a long-term historical increase in river flows (two stations) and sediment load (one station), largely attributed to changes in climate. In contrast, within the Blue Nile and Main Nile basins, there is a slight decrease of river flows at four selected stations under factual climate, which can be attributed to climate change, but no significant changes in sediment load (one station). These findings show spatial differences in the impacts of climate change on river flows and sediment load in the study area for the historical period.

From the Delta to The Delta: Natural Conditions and Settlers on the Main Nile in the Fifth Millennium B. C. Part IV (Conclusive)

From the Delta to The Delta: Natural Conditions and Settlers on the Main Nile in the Fifth Millennium B. C. Part IV (Conclusive)

Transboundary Nile basin dynamics: Land use change, drivers, and hydrological impacts under socioeconomic pathways

Landscape transitions in the Nile River basin will likely accelerate over the next decades due to socioeconomic developments and climate change. However, the assessments of land use/land cover (LULC) changes and their impact on the water resources over the Nile basin lacked a transboundary perspective. Here we used coupled basin-scale geospatial-hydrological models to project future LULC changes in the Nile basin and its three tributaries (i.e., White Nile, Blue Nile, and Atbara River), explored their drivers and projected hydrological impacts under different shared socioeconomic pathways (SSPs) during 2020–2060. Compared to 1992–2019, significant increases in the forested area (>50 × 103 km2) are expected to occur in the upstream areas of the White Nile and the Blue Nile in South Sudan and Ethiopia, with larger increases projected under higher emission scenarios. Consequently, it will likely reduce the downstream seasonal river discharge for the White and Blue Nile by up to 8.4% (SSP5) and 8.9% (SSP2), respectively. An increase of 7.4% in the Blue Nile discharge is expected during the flood season if the current urbanization/deforestation rates would prevail in the future. Large decreases (>15 × 103 km2) of unused land are expected in the Atbara River sub-catchment with increases in natural vegetation socioeconomic-related LULC types, leading to a river flow decrease of 15% during the rainy season under the SSPs. The basin-scale LULC changes are projected to decrease the Main Nile flow to Egypt by 3.6% under SSPs and increase by 2.1% if the historical trends prevail. The results highlight a close association between landscape dynamics, socioeconomic growth, and climate change over the Nile basin and suggest adaptive LULC planning and conservation measures.

From the Delta to the Delta: Natural Conditions and Settlers on the Main Nile in the Fifth Millennium BC. Part III

Neolithic in the Nile Valley in the 5th millennium BC was spread from the Sudanese Gezira to Central Egypt in the form of year-round settlements and seasonal camps of hunter-gatherers mastering the cattle breeding. Some researchers argued that it was a kind of cultural community, but this rather contradicts the known archaeological facts, which also do not confirm the theory of mass migration of the Neolithic tribes of the Sahara to the Nile in that era because of climate drying. Generally, “a convincing Neolithisation model” for this macroregion is still an actual problem of the Egyptian-Sudanese archeology. In the north, in Upper Egypt with the main concentration closer to Asiut, there are sites of the early Neolithic cultures of Tasa and Badari (the former is also considered as the initial stage of the latter) which preferred plateaus, wadis and edges of the adjacent “deserts” to the river floodplain; nevertheless, some scholars claimed the “Tasians” already to have been farmers growing cereals, although the available archaeological data allow us to speak at best about the beginnings of agriculture in the sparsely populated Tasian-Badarian Egypt. In the south, close to the confluence of the White and Blue Nile from the Gezira to the Sixth cataract, the culture of Khartoum Neolithic dominated, replacing Early Khartoum (Khartoum Mesolithic), from which it differed economically by the transition to cattle breeding; any traces of agriculture in its area, as well as in the early sites of the Saharan-Sudanese Neolithic, are absent. Khartoum Neolithic apparently experienced some drying of its containing landscape in the second half of the 5th millennium BC, and this could hardly be favored by the warm and moist climate at the peak of the Atlantic thermal optimum of the Holocene; most likely, there was a change in the hydrology and hydrography of the river network in the area of concentration of this culture, associated with the stabilization of the “meandering” estuary channel of the Blue Nile in its current position.

Cultural and natural context of the ancient settlement of Gebel el-Nour in the mouth of Wadi Ghayada (Middle Egypt): main challenges and prospects for studying

In 2022, the archaeological site of Gebel el-Nour witnessed the first season of the Egyptian-Russian archaeological mission organizes in cooperation between the Supreme Council of Antiquities of Egypt and the Institute of Oriental Studies of the Russian Academy of Sciences. This Greek-Roman site and its surrounding infrastructure have not attracted much attention of researchers besides archaeological works within the temple area built by Ptolemy II. The inauguration of the new international project may become an important step for Russian specialists in developing an integrated approach to Egyptian settlement archeology and regional studies of ancient and medieval sites in the Nile Valley. The paper deals with the history of the research on the archaeological zone of Gebel el-Nour, its layout and dating, the general archaeological context, as well as the surrounding cultural and natural landscapes. The author provides a brief review of the climatic changes that occurred during the history of the settlement and outlines the problem of reconstructing the migration of the main Nile channel at a local scale. The issue of the formation of a system of settlements on the territory of the XVIIIth Upper Egyptian nome and the problem of linking archaeological sites to toponymy preserved in written sources are also considered. The paper discusses the possible role of the site in exploiting large calcite quarries and in control over one of the contact zones on the border of the Nile Valley and the Eastern Desert. The purpose of this communication is to introduce the new monument into a wider regional context and to formulate priority issues and tasks related to its study.

Water quality of the Blue Nile at Khartoum, Sudan, before complete filling of the Grand Ethiopian Renaissance Dam

Physico-chemical variables were monitored biweekly for the Blue Nile at Khartoum between July 2017–June 2019. The aim was to document the present status of water quality at Khartoum before complete filling of the Grand Ethiopian Renaissance Dam (GERD). Physico-chemical parameters within acceptable limits recommended by WHO for drinking water included pH (7.2–10.8), temperature (13.7–30.4 °C), conductivity (137–281 μS cm−1), total dissolved solids (75–141 mg l−1), total residue (5–3194 mg l−1), alkalinity (93–176 mg CaCO3 l−1), dissolved oxygen (3.5–10.9 mg l−1), nitrite–nitrogen (<detection limit (DL)−43 µg l−1), ammonium–nitrogen (<DL−940 µg l−1), nitrate– nitrogen (<DL−1468 µg l−1), phosphate–phosphorus (<DL−63 µg l−1), silica (4.0–23.6 mg l−1), iron (<DL−250 µg l−1) sodium (3.2–15.7 mg l−1), potassium (0.7–5.6 mg l−1), calcium (6.2–30.3 mg l−1), and magnesium (1.5–11.5 mg l−1). Total residue and pH were amongst the measured variables that were outside of the WHO recommendations. This study revealed that the Blue Nile remains generally unpolluted, and has not been significantly negatively affected by runoff from urbanisation or sewage contamination. This study presents further evidence that industrial wastes discharged upstream of Khartoum have not accumulated downstream as they are carried into the Main Nile by the annual floodwater pulses. The water is therefore currently suitable for drinking and all other uses. However, accumulation of pollutants in the Blue Nile may be problematic once filling of the GERD is complete as the discharge during flooding events necessary to flush the river will be reduced.

Depositional environments in the White Nile Valley during the last 300,000 years

Before regulation, the White Nile contributed 83% of the low water flow to the main Nile and was responsible for maintaining the Nile as a perennial river during times of drought in Ethiopia. Two key unresolved questions relating to the White Nile are: (a) When did the White Nile first join the main Nile? (b) What type of sediment did the White Nile contribute to the main Nile? The answer to the first question has important implications for our understanding of hydro–climatic and tectonic events in the Ugandan Lake Plateau. The answer to the second question is essential for correctly interpreting the sedimentary record preserved in the Nile deep sea fan in the eastern Mediterranean. Our work has shown for the first time that the White Nile has been transporting smectite–rich sediments from the time of its probable inception over 240 ka ago and possibly since about 400 ka. Our analysis of the heavy mineral assemblages in White Nile alluvial sediments provides strong support for a source in the Lake Plateau region of Uganda. The White Nile was flowing from Uganda by at least 240 ka and very likely from about 400 ka.

From the Delta to the Delta: Natural Conditions and Settlers on the Main Nile in the Fifth Millennium BC. Part I (Introductory)

The 5th millennium BC is marked by the transition to agriculture in the Egyptian Nile valley, rather late for the Fertile Crescent. This was preceded by the Quaternary epic of discovery of the Nile banks by hominids, from the Olduvian Pithecanthropus of the lower Palaeolithic to the Neolithic settlers of the Predynastic period, who laid the socio-economic foundation of the Pharaonic civilization. In the Pleistocene geological epoch, the Main Nile underwent a complex evolutionary transformation from palaeo-rivers with such powerful watercourses as the Prenile to the much inferior in volume Neonile on which, at the 2nd marine isotope stage (27.8–14.7 ka) when the Sahara was a hyperarid desert, comparatively frequent Paleolithic sites of gatherers, fishermen and hunters arose in Upper Egypt and Lower Nubia (the archaeological cultures Halfa, Fakhuri, Qadan, Ballana, Silsila, Afia, Makhadma et al.). Warming and humidification of the climate with the onset of the 1st marine isotope stage was accompanied by an “abrupt return” of the summer monsoon rains to East Africa and an episode of the “Wild Nile” with the incision of the River, which probably made its Egyptian valley unsuitable for settlement by the beginning of the Holocene (11700 ± 99 ka); thus, the Epipalaeolithic is represented here by rare industries of Elkab in Upper Egypt and Karun in the Fayum oasis. At the same time, from the 9th millennium BC there was an increase in the population of the Sahara, where during the African humid period of the early Holocene grassy and woody savannahs were spreading. The Nile Delta with its “historical” network of branches had not yet formed and represented a barren sandy plain which (as well as the Valley) was unsuitable for life and the establishment of the food-producing economy. Simultaneously in Sudan, in the Gezira region at the confluence of the White and Blue Nile, an inner delta was formed, which may have been the cause of the later Neolithization of the lower reaches of the Main Nile.

From the delta to the Delta: Natural Conditions and Settlers on the Main Nile in the Fifth Millennium BC. Part II

The primordial neolithization on the banks of the Nile River is associated with the archaeological culture of the Early Khartoum, or Khartoum Mesolithic. The bulk of its monuments date back to the 7th–6th millennia BC and is located on a long stretch of the river valley from the Gezira at the confluence of the White and Blue Nile to the 2nd cataract of the Main Nile at the current border of Sudan and Egypt. Khartoum Mesolithic shows a tendency of enlarging its sites southwards probably connected with a progress of settled way of life of the early Neolithic population of this stretch approaching to the Gezira. The latter at that time was dissected by the paleochannels of the inner Blue Nile delta that discharged into the White Nile and was a swampy fertile alluvial plain, very similar to the Egyptian Delta that was formed two or three millennia later. Favorable climatic conditions of the African Humid Period (about 14.8 — 5.5 cal. yr BP) did not favor the mass migration of the inhabitants of the blooming Sahara to the Nile, as evidenced by numerous sites of the Saharo-Sudanese Neolithic in the Western Desert. According to recent paleoclimatic reconstruction by S. Kröpelin, a large-scale demographic shift from the Desert to the River, caused by abrupt desiccation of the North Africa and resulted in the epoch-making progress of the Neolithic communities on the Nile, including Egypt, took place starting from 5300 BC. This model, however, contradicts the available scientifical data and has no archaeological confirmation. An absolute majority of studies at the junction of archeology and paleoecology show that cooling and aridization that could have caused a mass migration of people from the Sahara to the banks of the Nile, developed only with the completion of the Holocene Atlantic optimum and, in general, the African Humid Period in the 4th millennium BC having reached the extremum at about 4500 uncal. yr BP ≈ 3221 BC. All earlier manifestations of neolithization on the Nile from the natural point of view should be obviously explained primarily by the attractiveness for people of the Nile Valley itself or of its individual parts and basins, such as the delta of the Gezira.

Load Rating of Al Halfaia Bridge over the Nile

This paper summarizes the results of applying load rating process that has been applied to Halfaya Bridge over the main Nile in Khartoum, Sudan. Load rating procedures have reviewed as per Manual of Bridge Evaluationof AASHTO Standards. Three levels of H/Y live loadings have been considered. AASHTO HL-93 is used for design load rating. For Legal load rating the Sudanese legal loads - as per Sudan National Highway Authorityare considered. Permit load rating process has been made using actual special heavy truck used in Sudan during the last 20 years .The rating process has been made on the assumption that the capacity of the main structural element of the bridge, which is Girder type II Composite Steel Ibeams, had been decreased with different percentage from 10%up to 20%, due to different factors. Suitable software, CSi Bridge, has been used for calculations and the results are presented. The paper predicted the load rating factors for the composite steel I-beams of the bridge- moment and shear wise- for considerable capacity loss in future .The paper also checked the deflection of the composite I-Girder .Results showed that deflection is the governing factor when stiffness is lost by 8%, but still the momentcapacity is the governing factor –design load rating –when the loss is 5%of the capacity. Suggested several recommendations to save such vital structure are given

Nile River clayey materials in Sudan: Chemical and isotope analysis as reference data for ancient pottery provenance studies

This research aims to define a chemical, mineralogical and strontium isotope database for clayey materials collected along the Nile River banks (White Nile, Blue Nile, Atbara and Main Nile Rivers) in Sudan, to be use for prehistoric and historic pottery provenance studies. The approach here adopted consists in using the clayey materials tout court, without any pre-treatment, such as the depuration from the sand- and silt-sized fractions, in order to maintain unaltered the mineralogical and geochemical features of the natural resources possibly available also in ancient times for the pottery production, thus avoiding any possible preparation bias. Results indicate that sediments along different sections of the Nile River display characteristic geochemical and strontium isotopic signature, representing an important discrimination tool applied to ancient ceramics provenance and human mobility studies.

Changes in the physicochemical and biological characteristics in the lentic and lotic waters of the Nile river

This study aims to compare the changes in the physicochemical and biological characteristics simultaneously in Nasser Lake as lentic water and the main Nile River as lotic water due to the construction of the Aswan High Dam. Therefore, water samples were seasonally collected from four sites along the lentic water and five sites along the lotic water. The results showed an increase in the water temperature and pH in the lentic than the lotic waters, while TSS, nutrients, BOD, and TDS showed a reverse trend. Furthermore, zooplankton recorded 45 taxa; 31 rotifers, 7 cladocerans, and 3 copepods, in addition to 4 taxa represented in rare groups. Rotifera dominated the main river water, while Copepoda dominated Nasser Lake water. Twenty-two holozooplankters appeared only in the main river water, while three holozooplankters appeared in the lake water and 20 holozooplankters were shared in both waterbodies. The appearance of Ptygura libera in the river for the first time proved that the lake is the source of some zooplankters in the river. According to the trophic state index and the river pollution index calculations, the two waterbodies categorized as eutrophic and unpolluted, respectively.

The Main Nile Valley at the End of the Pleistocene (28–15 ka): Dispersal Corridor or Environmental Refugium?

Under present environmental conditions, the Nile Valley acts as a ‘natural’ route between Africa and Eurasia, and is often considered as a corridor for dispersals out of and back into Africa in the past. This review aims to address the role played by the Nile Valley at the end of the Pleistocene (28-15 ka) in the context of post-‘Out of Africa’ modern human dispersals. Genetic studies based on both modern and ancient DNA suggest pre-Holocene dispersals ‘back into Africa’ as well as genetic interactions between modern humans across Africa and the Levant. During the Last Glacial, the lowering, or even complete desiccation of major eastern African lakes, including Lake Victoria, reduced the White Nile to a highly seasonal river, depriving the main Nile from its most important tributary in the dry season. This had major consequences, the specifics of which are still debated, on the behavior of the main Nile and the landscape around the Nile Delta. Despite this shift to more arid conditions, there is abundant evidence for human occupation in the main Nile Valley. Combining available geological, palaeoenvironmental, anthropological, genetic and archaeological data, this article discusses problems encountered when trying to reconcile results from different fields, the current limitations of the available data and research perspectives to further address the role of the Nile Valley as a dispersal corridor or an environmental refugium at the end of the Pleistocene.

Seasonal levels of pesticide residues in the main and the Blue Nile waters in Sudan

Levels of twenty-two commonly used pesticides were monitored three times a year (autumn, winter, and summer) in 54 water samples collected from six sites representing the main and Blue Nile. These sites were selected to reflect any attributes from main drainage canals from agricultural schemes in Sudan as well as any impact from upstream sources. Collected samples were subject to gas chromatographic analysis equipped with FID/ECD, and results were expressed in ng/l water. Analysis of Blue Nile water indicated the presence of OCs in 45% of the samples, OPs in 11%, pyrethroids in 22%, and none of the tested herbicides. Heptachlor and DDTs were the most prevalent followed by the pyrethroids. Levels detected were not high. Water of the main Nile showed the presence of OCs in 22% of the samples, pyrethroids in 4%, and none of the tested OPs and herbicides. DDT is the most prevalent followed by heptachlor. Total concentration in main Nile is relatively higher than the Blue Nile. Residues of DDD, λ cyhalothrin, deltamethrin, oxyfluorfen, HCH, and endosulfan isomers were not detected in the analyzed samples. Generally levels were least in autumn, followed by summer and winter. Sources of contamination might include some drains from agricultural lands in central Sudan and/or upstream sources. Both recent and old contaminations were indicated.

Hydrological Impacts of the Grand Ethiopian Renaissance Dam (GERD) on River Nile Hydrology Within Sudan

This paper aims to quantify the potential impacts of the Grand Ethiopian Renaissance Dam (GERD) on the River Nile System within Sudan territories, in the context of hydrology. GERD reservoir with a capacity of (74 Km3) is approximately 1.5 times the mean annual flow of the Blue Nile, which contributes by 57% of the River Nile runoff. According to Ethiopian proposal, the GERD is going to be filled to the full supply level of 640 m a.m.s.l in 6 to 7 years. The first filling of GERD reservoir was planned to be in 2014, but it is postponed until the writing of this report. However, it's most likely to be started this year 2020. Consequently, significant impacts are highly anticipated during this first filling period, and all over the long-term operation. Definitely, this will change the Blue and Main Nile hydrological regime. In order to achieve the research objectives, a daily time step Rule Based Simulation model has been developed using River Ware Software (University of Colorado) representing the entire River Nile system within Sudan. Three scenarios were adopted, baseline (Hydrological System without GERD), GERD first filling and long-term operation. River inflows, water levels, run-off and hydrograph shapes within Sudan water system were investigated and compared to the average baselines, taking into consideration the recent Dams’ operation policies and rules. In addition, a simple-approach operation scenario was adopted for GERD. Likewise, as hydrological inputs, 30 years of historical time series were used. Given the above, the hydrological impacts in six representative River Nile reaches within Sudan were estimated, then highlighted and judiciously investigated. In summary, it could be concluded that, during the first filling of GERD, the runoff of the Blue Nile will decrease by 30%. While, for the Long Run, significant changes are expected for to the Blue Nile hydrograph, resulting in slight to moderate changes for the Main Nile Hydrograph. It’s expected that the impacts of GERD on River Nile hydrology will lead to increasing average discharges during summer period by a range of 10 - 500% for different months and hydrology, on the other hand, reducing flood peak by approximately 10-25%. In the long run, Water Levels in different reaches are expected to vary by ± (2 to 3) meters. It's concluded that operation policies of the existing Sudanese dams will no longer be valid for the new Situation after GERD, further studies are highly recommended to be conducted.

Spatial distribution of unidirectional trends in climate and weather extremes in Nile river basin

The recent finding of the influence of long-term persistence (LTP) in time series on trend significance has made the past findings of climatic trends in the Nile river basin (NRB) disputable. Four versions of the Mann-Kendall test including the latest one which considers the LTP in time series have been used in this study to distinguish the unidirectional trend from natural variability of climate in NRB. The gridded Princeton global meteorological forcing data having 1-day and 0.25° temporal and spatial resolution, respectively, for the available period 1948–2010 was used. The results showed that the number of grid points showing a significant change in climate and weather extremes reduced drastically when LTP in time series was considered. The annual rainfall was increasing only at some locations in the main Nile and Atbara sub-basins at a rate of 0.26–26.4 mm/decade while decreasing in Sobat sub-basin up to − 76.6 mm/decade. The maximum temperatures were increasing in the main Nile, Atbara, Blue Nile, Bahr Elgazal, and Bahr Eljabel at a rate of 0.09–0.48 °C/decade, while the minimum temperatures were increasing in most parts of the NRB by 0.17–0.50 °C/decade. Among the weather extremes, a significant trend over a large part of NRB was found for extreme rainfall days (− 0.53–0.75 day/decade), cold nights (− 6.05–3.26 days/decade), heat waves (0.29–2.00 days/decade), and cold waves (− 4.05–1.15 day/decade).

Survival of E. coli O157:H7, Salmonella Typhimurium, HAdV2 and MNV-1 in river water under dark conditions and varying storage temperatures

The ability of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, Human adenovirus serotype 2 (HAdV2) and Murine Norovirus 1 (MNV-1) to survive in river water at −20, 4, room temperature (~24 °C) and 37 °C, were evaluated under dark conditions. The tested surface water was obtained from the main Nile River in the Dokki area, Giza and sterilized by autoclaving. The pathogens were inoculated separately in the autoclaved river water. Each microcosm was sampled and the test microorganisms counted after zero (immediately following inoculation), 1, 7, 15, 30, 60, 90 and 120 days. Physicochemical parameters including pH, turbidity, electrical conductivity, dissolved oxygen, total dissolved solids, total alkalinity, biological oxygen demand, chemical oxygen demand, nitrates and nitrites, and sulphate, were also measured. For HAdV2, the highest decay rates were observed at 37 °C and room temperature compared to 4 and −20 °C. A similar trend was found for the MNV-1, although unlike the HAdV2, the decay rate was higher at −20 than at 4 °C. Also, 4 °C was the best temperature for the survival of MNV-1 (T90 = 76.9 days), E. coli O157:H7 (T90 = 103 days) and Salmonella Typhimurium (T90 = 105 days). The least survival of the pathogens, except MNV-1, was recorded at 37 °C. These results indicate that under dark conditions and low temperatures, enteric pathogens could be stable for extended periods. No significant statistical correlation was observed between the experimental temperatures and the infectivity of the viral particles. This study provided useful information about the stability of these pathogens in the Nile River water and could serve as an early warning when considering the water of the river for agricultural irrigation or household use in areas with limited or no access to potable water.

The White Nile as a source for Nile sediments: Assessment using U-Pb geochronology of detrital rutile and monazite

Basement terranes exposed at the headwaters of the White Nile include Archean-Paleoproterozoic rocks of the Congo Craton, whose northern sectors were severely reworked during Neoproterozoic orogeny. New U-Pb analyses of detrital rutile and monazite from early Quaternary to Recent coastal quartz sands of Israel, at the northeast extension of the Nile sedimentary system, yield mostly late Neoproterozoic ages, with a dominant peak at ca. 600 Ma. While derivation from the reworked sectors of the Craton cannot be negated, the absence of pre-Neoproterozoic rutile and monazite indicates that the detrital contribution from the Congo cratonic nuclei into the main Nile was insignificant.The near absence of White Nile basement-derived heavy minerals from the Nile sands arriving at the Eastern Mediterranean may be explained by a number of factors such as relatively minor erosion of the Cratonic basement nuclei during the Quaternary, late connection of the White Nile to the main Nile system with a possibility that northern segments connected prior to more southerly ones, and a long-term effective sediment blockage mechanism at the mouth of White Nile. Likewise, our previous study demonstrated that Nile sands display a detrital zircon U-Pb-Hf pattern consistent with significant recycling of NE African Paleozoic sediments. It is thus plausible that any detrital contribution from White Nile basement rocks was thoroughly diluted by eroded Paleozoic sediments, or their recycled products, which were likely the greatest sand reservoir in the region.This study adds to previous studies showing the advantage of a multi mineral U-Pb geochronology strategy in constraining sediment provenance patterns.

Holocene alluvial history and archaeological significance of the Nile floodplain in the Saqqara-Memphis region, Egypt

A suite of drill cores undertaken on the Saqqara-Memphisfloodplain revealed an array of Late Pleistocene-Holocene sediment facies that show a complex of spatio-temporal changes in sediment related to migration of the River Nile, Nile flood variations, settlement sites and climate change. The recovered data enhance our understanding of the history of the modern River Nile and its relationship to the emergence and continuity of Egyptian civilization.The floodplain of the Saqqara-Memphis area reveals a sequence of aggradation and degradation events comprising six clearly marked sedimentary units (I-VI), overlying Late Pleistocene fluvial sand and gravel (unit I). Deposition of unit II resumed during a period of high Nile flow, rapid sea level rise and locally wet climatic conditions. As a result, the floodplain was occupied by swamps and anastomosing channels. Subsequently, the Nile changed to a more stable meandering channel system with well-developed levees and flood basins (unit III). This aggradation unit was subsequently eroded by the end of Old Kingdom (ca. 4.2 kyr cal BP). The degradation hiatus was followed by a widespread layer of alluvial silt and sand indicating very high Nile floods that coincide with historical records of very high floods during the Middle Kingdom and frequently high floods during the New Kingdom (unit IV). During the last two thousand years (units VI-VII) floods generally diminished except for several notable lows and highs.Our calculations of the long-term rate of siltation during the Middle and Late Holocene suggest an average rate of 0.235 m/century rather than the commonly cited 0.09–0.12 m per century. In addition, our study of satellite imagery of the Memphite region in the context of archaeological data combined with our own geological studies reveal that the main Nile in Neolithic and Predynastic times (ca.7.0–5.0 kyr cal BP) ran along the eastern edge of the current floodplain. A lateral branch of the Nile ran along the western edge of the floodplain. It is on the bank of this branch that the first capital of a unified Egypt was established. Our cores also reveal during the Dynastic period, the western branch shifted eastwards, while the main Nile shifted westwards.