Publications by authors named "Ahmed Sefelnasr"

The lack of perennial streams or surface water in most arid countries necessitates input modification and water scarcity/security equation calculation as per the water resource systems and physiographic conditions in these countries. The contributions of nonconventional and virtual water resources to water security have been disregarded or undervalued in previous research on global water scarcity. This study addresses this knowledge gap by developing a new framework for estimating water scarcity/security.

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The intensive agricultural expansion and rapid urban development in Abu Dhabi Emirate, United Arab Emirates (UAE) have resulted in a major decline in local and regional groundwater levels. By using the latest release (RL06) of Gravity Recovery and Climate Experiment (GRACE) satellite measurements and Global Land Data Assimilation System (GLDAS) products, the groundwater storage change was computed and compared with the time series of in-situ monitoring wells over the period of 2010-2016. The RL06 GRACE products from Jet Propulsion Laboratory (JPL), University of Texas Center for Space Research (CSR), German Research Center for Geosciences (GFZ), and JPL mass concentrations (MASCON) were assessed and have shown satisfactory agreements with the monitoring wells.

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Accurately predicting meteorological parameters such as air temperature and humidity plays a crucial role in air quality management. This study proposes different machine learning algorithms: Gradient Boosting Tree (G.B.

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Rivers carry suspended sediments along with their flow. These sediments deposit at different places depending on the discharge and course of the river. However, the deposition of these sediments impacts environmental health, agricultural activities, and portable water sources.

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In this study, the analysis of the extreme sea level was carried out by using 10 years (2007-2016) of hourly tide gauge data of Karachi port station along the Pakistan coast. Observations revealed that the magnitudes of the tides usually exceeded the storm surges at this station. The main observation for this duration and the subsequent analysis showed that in June 2007 a tropical Cyclone "Yemyin" hit the Pakistan coast.

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Article Synopsis
  • Rapid growth in nitrogenous compounds like nitrate and ammonia in rivers is linked to agricultural and industrial activities, leading to issues like eutrophication and 'blue baby syndrome.'
  • The study focuses on developing an optimal artificial neural network model to predict monthly average values of these compounds using hydrological data from Malaysia, specifically the Langat River.
  • Three different neural network architectures (GRNN, Multilayer Neural Network, and RBFNN) were tested, with the best-performing model achieving a regression value of 0.92, indicating strong predictive accuracy.
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Article Synopsis
  • Streamflow patterns are complex and can change unpredictably, making it important to develop accurate forecasting models for water resource management.
  • The study focuses on optimizing input variable combinations for better model reliability and introduces a Genetic Algorithm (GA) to select the best input variables for streamflow forecasting.
  • Using a Radial Basis Function Neural Network (RBFNN) integrated with the GA, the model demonstrated high forecasting accuracy for streamflow at the High Aswan Dam on the Nile River.
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Bank filtration (BF) has been used for many years as an economical technique for providing high-quality drinking water. However, under anaerobic conditions, the aquifer release of undesirable metal(loid)s, such as iron manganese, and arsenic, reduces the bank filtrate quality and thus restricts the application of this technique. This study investigates the impact of the organic-matter composition of source water on the mobilisation of Fe, Mn, and As during the anaerobic BF process.

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Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry.

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