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Modeling the hydrodynamic interactions between the river morphology and navigation channel operations

Neveen Badawy Abdel-Mageed, El-Hazek Alaa N., Elsersawy Hossam Mohamed, Mohammed Ebtesam Rezk

Journal of Water and Land Development

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2021

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no. 51

1--10

EN

The Nile River is the main route for inland navigation in Egypt. The vessels navigating through inland waterways generate complex physical forces that need to be studied extensively. Quantifying the effects of vessels sailing along a waterway is a complex problem because the river flow is unsteady and the river bathymetry is irregular. This paper aims to investigate the hydrodynamic effects resulting from the movement of vessels such as return currents around the vessel, the draw down of the water surface, under keel clearance, and the shear stress induced by vessels operating in the Nile River. Modeling such effects has been performed by applied the two-dimensional ADH (adaptive hydraulics) model to a river reach for different navigation channel operation scenarios. The obtained results show that the draw down heights, the water fluctuation, and the shear stress magnitude are larger when the river cross sectionals are narrow and the shallow water depths. These river sections are considered more disposed to bed erosion and it is morphologically unsafe. The section having the narrowest width and the lowest depth was associated with the largest drawdown percentages of 98.3% and 87.3% in one-way and two-way scenarios. While the section having the widest width and the largest depth was associated with the least drawdown percentages of 48.5% and 51.9% in one-way and two-way scenarios. The section having the narrowest width and the lowest depth was associated with the largest fluctuations of 22.0 cm and 41.9 cm in one-way and two-way scenarios. While the section having the widest width and the largest depth was associated with the least fluctuations of 0.6 cm and 1.8 cm in one-way and two-way scenarios. The section having the narrowest width and the lowest depth was the worst section for under keel clearance of 5.0 cm and 33.3 cm in one-way and two-way scenarios. While the section having the widest width and the largest depth was the best section, where its clearance values were 183.2 cm and 155.0 cm in one-way and two-way scenarios. It is concluded that a numerical model is a valuable tool for predicting and quantifying the hydrodynamic effects of vessels moving through a two-dimensional flow field and can be used to evaluate different scenarios that are difficult to measure in the field or a physical model. Also, it provides visualization products that help us understand the complicated forces produced by vessels moving in a navigation channel.

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Risk assessment of heavy metal pollution in water, sediment and plants in the Nile River in the Cairo region, Egypt

Al-Afify Afify D.G., Abdel-Satar Amaal M.

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 1

1--12

EN

Samples of water, sediment and two native plants (Eichhornia crassipes and Ceratophyllum demersum), collected seasonally from eight sites, were analyzed to investigate the level of contamination with metals (Fe, Mn, Ni, Co, Zn, Cu, Cr, Pb and Cd) in the Nile River in the Cairo region, using heavy metal pollution and contamination indices in the case of water, and the geoaccumulation index, the pollution load index, the enrichment factor and the potential ecological risk factor in the case of sediment. The results clarified that the levels of metals among three compartments were in order: sediments > plants > water. The Nile water in Cairo is not critically polluted by the studied metals and the metal pollution index for most sites does not exceed the critical limit (< 100). Sediment samples showed a clear accumulation of Mn, Ni and Cd when compared with benchmarks cited by the Environmental Protection Agency (EPA), especially during low flow seasons. The contribution of Cd to the ecological risk assessment was about 80%, while the contribution of Ni was about 10%, reflecting that these elements originated primarily from anthropogenic sources. Eichhornia crassipes and Ceratophyllum demersum have a higher accumulation capacity for Mn, Cu and Fe compared to the other studied metals.

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Integrated approach to quality indices and health risk assessment of water in the Bahr Yusuf Canal, Fayoum, Egypt

Hassouna Mohamed E.M., Goher Mohamed E., El-Sayed Seliem M., Hassan Reda A.A.A.

Oceanological and Hydrobiological Studies

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2019

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Vol. 48, No. 4

337--354

EN

The Bahr Yusuf Canal is the life artery of the Fayoum Province, which provides the province with two thirds of the freshwater quota from the Nile River. The present work was carried out to assess the suitability of water in the Bahr Yusuf Canal for various purposes and to assess the potential health risk associated with metal content. The results showed that the water quality of Bahr Yusuf was classified as poor and very poor for recreational use according to the Oregon WQI. On the other hand, the Aquatic Toxicity Index indicated the suitability of water for all fish species. The Canadian WQI and the Weighted Arithmetic WQI classified the canal water as good (WQI = 92), fair (WQI = 73) & marginal (WQI = 64) and excellent, poor to good & good to excellent for irrigation, drinking and aquatic life, respectively. Despite the significant contamination of water with heavy metals (as indicated by the Heavy Pollution Index, ranging from 104.44 to 206.32, from 16.81 to 38.48 and from 219.07 to 472.24 μg l−1), the Hazard Quotient (HQ) and the Hazard Index (HI) data indicate that water of Bahr Yusuf does not pose a human health risk through ingestion or dermal contact. In general, the study showed that water in the Bahr Yusuf Canal is characterized by different levels of pollution, which requires rapid and critical intervention by responsible authorities to prevent the discharge of different types of waste and further deterioration of the water quality during the lifetime of the channel and its subsequent rehabilitation.

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Evaluation of spatial and temporal variations of surface water quality in the Nile River Damietta branch

El-Tohamy W. S., Abdel-Baki S. N., Abdel-Aziz N. E., Khidr A. A.

Ecological Chemistry and Engineering. S

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2018

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Vol. 25, nr 4

569--580

EN

The objective of this study is to reveal the spatial and temporal variations of surface water quality in this part of the River Nile with respect to heavy metals pioneerution. Seventeen parameters in total were monitored at seven sites on a monthly basis from October 2013 to September 2014. The dataset was treated using the tools of univariate and multivariate statistical analyses. Cluster analysis showed three different groups of similarity between the sampling sites reflecting the variability in physicochemical characteristics and pollution levels of the study area. Six PCs factors were identified as responsible for the data structure explaining 91 % of the total variance. These were eutrophication factor (23.2 %), physicochemical factor (20.6 %), nutrients (16.3 %) and three additional factors, affected by alkalinity and heavy metals, recorded variance less than 15 % each. Also, the heavy metals pollution index (HPI) revealed that most of the calculated values were below the critical index limit of 100. However, two higher values (124.89 and 133.11) were calculated at sites V and VI during summer due to the temperature and increased run-off in the river system.