Description: Publication date: Available online 21 February 2018 Source: Water Science Author(s): M. Bahgat Coastal zone of Egypt Nile Delta is exposed to an extensive changes due to natural and artificial influences. These changes have induced erosion problems along coastlines of Nile Delta. Near or foreshore replenishment is an alternative approach in many areas instead of hard structures to avoid negative impact of coastal structures. The frequent maintenance dredging works of ports approach channels could be considered as possible sources of sand, which may be used to address sediment budget and to help overcome coastal erosion at key strategic locations. Two-dimension morphological numerical model (2DH) was developed using Delft3D to study and predict the effect of using dredged sediment from the approach channel on minimizing the retreat of shoreline at the area subjected to erosion. The morphological simulation runs included 8 model scenarios to test the effect of dumping the dredged materials at various locations with different quantities. Analysis of model results were carried out to assess the optimum location and quantities of the nourishment using the dredged materials. The results showed that, the directly placement of dredged materials at shoreline was found to be the most effective choice enhancing the stability of the shoreline. The applications through the current case study could help and guide for integrated management processes and practice.

Description: Publication date: Available online 19 February 2018 Source: Water Science Author(s): Raksmey Ang, Chantha Oeurng The study objective of this work is to test the applicability of the Soil and Water Assessment Tool (SWAT) model to simulate the streamflow through calibration and validation for both daily and monthly basis in the Stung Pursat River catchment, an ungauged sub-catchment of Tonle Sap Basin in Cambodia. In order to achieve the objective of the study, SWAT model was set up with study period of 10 years (2001–2010). Additionally, ArcSWAT2012 and ArcGIS10.2.2 combined with Sequential Uncertainty Fitting-2 (SUFI-2) algorithms were used to conduct uncertainty analysis, calibration and validation of the SWAT model using daily observed streamflow data at the catchment outlet. Daily simulation produced the results with Nash-Sutcliffe Simulation Efficiency (NSE) of 0.38, Percent Bias (PBIAS) of +5.1% and Root Mean square error-observation standard deviation Ratio (RSR) of 0.79 in calibration period, and with NSE of −6.61, PBIAS of −78.38% and RSR of 2.67 in validation period. The streamflow results of monthly time series were improved and acceptable with NSE of 0.60 while decrease the value of PBIAS and RSR to 1.14, and 0.63 respectively. The SWAT model should be used to simulate monthly streamflow in such an ungauged catchment like the Stung Pursat catchment due to data scarcity and uncertainty.

Description: Publication date: Available online 16 February 2018 Source: Water Science Author(s): Faiza Hallouz, Mohamed Meddi, Gil Mahé, Salaheddine Alirahmani, Abdelkader Keddar The objective of this study is to model discharge and solid erosion quantification through a small agricultural watershed by applying the SWAT model (Soil and Water Assessment Tools) on the Wadi Harraza’s basin of which is part of Wadi Cheliff’s basin, with an average altitude of 500 m, drains an area of 568 sq km. Soil and Water Assessment Tool (SWAT, version 2009) model integrated with Geographic Information System (ArcGIS, version 10.0) were used to simulate the discharge and sediment concentration of Wadi Harraza’s basin for the period from 2004 to 2009. Model calibration and validation were performed for monthly time periods using Sequential Uncertainty Fitting 2 (SUFI-2, version 2) within SWAT-CUP. Our calibration and validation outputs for monthly simulation showed a good model performance for discharges. Thus the evolution of the average total annual sediment in the Wadi Harraza’s basin which will be deposited in the Wadi Cheliff, is estimated at 54.24 t ha −1 .

Description: Publication date: Available online 19 February 2018 Source: Water Science Author(s): Amin Elshorbagy, Kelsea Lindenas, Hossein Azinfar Storm water detention ponds are usually designed to store-and-release the runoff of extreme rainfall events based on a selected return period, e.g., 100 years. The design storm is typically a recorded historical event or one that is extracted from historical intensity–duration–frequency (IDF) curves. In essence, the selected storm and the resulting design are deterministic. In this research, the inevitable natural weather variability and its impact on the uncertainty of extreme events are simulated and quantified. This study builds on the results of a previous study where a stochastic weather generator, LARS-WG, was used to generate an ensemble of series with a 30-year length of hourly rainfall in the city of Saskatoon, Canada, based on the statistical properties of historical rainfall. Here, the most critical day (24-h rainfall) of each of the series is identified as a possible realization of the design storm. The runoff of each realization of the storm events is routed to a storm water pond in Saskatoon using the XPSWMM model. The critical runoff volume collected in the pond throughout the 24-h duration is also identified. Empirical probability distributions are fitted to the critical values of runoff volumes collected in the pond and compared with the current design storage. Exceedance probabilities and expected flood risk are estimated from the probability distributions for the baseline period (1960–1990), as well as under three projected future (2014–2100) scenarios of climate change (RCP 2.6, 4.5, and 8.5). Along with the magnitude of expected risk, this method provides the probability of the infrastructure’s failure due to uncertainty. The proposed risk-based approach presented in this study provides a way for municipalities to quantify the risk associated with their selected design values and for tangible and meaningful interpretation of the risks that projected climate change might pose on storm water infrastructure. The main finding of this study is that the distribution of rain throughout the storm event may play a more important role than the total rainfall depth when water ponding/flooding is the major concern. It is further concluded that risk analysis must be tailored to the type of infrastructure under consideration.

Description: Publication date: Available online 6 December 2017 Source: Water Science Author(s): Mohammed Taha Moustafa Nanotechnology are fast advancing and currently became more effective than the conventional technologies used in water treatment that offers safe opportunities for using unconventional water supply sources. Fungi are more versatile in growth and metal tolerance in contrast to bacterial population. This work aims to demonstrate the extracellular synthesis of silver nanoparticle by using two filamentous fungi Penciillium Citreonigum Dierck and Scopulaniopsos brumptii Salvanet-Duval isolated from Lake Burullus, examine the biosynthesized nano-silver particles by UV–vis spectroscopy, transmission electron microscopy (TEM). The functional group of protein molecules surrounding AgNPs was identified using Fourier transform infrared (FTIR) analysis. Check the antibacterial activity of biosynthesized silver nanoparticles at two concentrations (550.7 and 676.9 mg/l) and interact it with bacteria for different durations (15, 60 and 120 min). Polyurethane foam was used as silver carrier and nano-silver solution for the removal of pathogenic bacteria in polluted water. The synthesized AgNPs showed an excellent antibacterial property on gram positive and gram negative bacterial strains.

Description: Publication date: Available online 6 December 2017 Source: Water Science Author(s): Abhishek Saxena, Manish Bhardwaj, Tanu Allen, Satish Kumar, Rachana Sahney

Description: Publication date: Available online 27 November 2017 Source: Water Science Author(s): Mohamed I. Azzam, Safaa M. Ezzat, Badawi A. Othman, Khaled A. El-Dougdoug This study aims to determine the impact of five main drains as sources of antibiotics resistant bacteria in River Nile at Rosetta branch, and to generate a baseline data on their virulence ability. Out of 212 bacterial isolates, 39.2% and 60.8% were recovered from drains and Rosetta branch, respectively. Susceptibility of bacteria to different antibiotics showed multiple antibiotics resistances (MAR) for the majority of isolates. Meanwhile, sensitivity was mostly directed to ofloxacin and norfloxacin antibiotics. Calculated MAR index values (>0.25) classified area of study as potentially health risk environment. Testing virulence ability of bacteria from drains showed positive results (65%). Contrastively, virulent strains in Rosetta branch were mostly lacking in this study. Concluding remarks justify the strong correlation (r = +0.82) between MAR and virulence of bacteria in polluted aquatic ecosystems, and highlight the potential of drains as reactors for their amplification and dissemination. The study suggests regular monitoring for antibiotics resistance in native bacteria of River Nile, prohibition of unregulated use of antibiotics, and proper management for wastes disposal.

Description: Publication date: Available online 21 November 2017 Source: Water Science Author(s): Hossam Elsersawy, Noha Kamal In recent years there are needs to initiate the efforts towards developing evaluation tool for the navigation condition of the existing berths on the Nile River. Main goals of the research are to develop GIS application for the berths data and link it to a numerical model for evaluate morphological and hydraulically changes at the berthing area. The established application is used to evaluate the existing berths conditions at Luxor reach. The investigation included the physical, hydraulic, morphological, navigation conditions for safe and reliable navigation operation. The model was applied to create base flow map for morphological and hydraulically changes at the berthing areas. It was indicated that the rate of deposition is much more than the rate of erosion. It is concluded that the percentage of 26% of the existing berths are satisfied the navigation depths conditions, the percentage of 58% require maintained dredging and the percentage of 16% of the existing berths does not satisfy the navigation depths conditions. The developed evaluation tool is essential for improving and the rehabilitation the navigation conditions of the existing berths.

Description: Publication date: Available online 6 November 2017 Source: Water Science Author(s): Mohamed M. Sobeih, Nahed E. El-Arabi, Esam El Deen Y. Helal, Basma S. Awad The present study was initiated with the objective of simulating and predicting the effect of future development on the groundwater flow and levels. This supports applications for future planning and wise management of water resources. The study area extends south of El Nubariya canal including Sadat City area and its vicinities in the western Nile delta region. A numerical groundwater flow model (MODFLOW) has been employed to simulate flow and get the budget of groundwater in the study area. The model showed that about 28,101,041 m 3 /day of surface water is infiltrated to groundwater dominantly from canals and excess irrigation water. About the same quantity (28,101,052 m 3 /day), is discharged from groundwater through production wells, open drains and through some reaches of canals. Three development scenarios were simulated to give predictions of the impact of future increasing recharge, construction of new canal and new open drains, and also increased pumping on the groundwater levels in the study area.

Description: Publication date: Available online 27 October 2017 Source: Water Science Author(s): Mohie Eldin Elmashad Problems associated with expansive soils in Egypt are predominantly related to the presence of montmorillonite clay minerals in the soil with fresh water. In this paper we are trying to solve the swelling problem of bentonite by using the chemical additives such as ammonium chloride, sodium chloride sodium carbonate and lime. This paper presents the results of an experimental investigation performed to quantify the effect of mixing bentonite which represent the swelling soil in homogenies phase with chemical additives such as ammonium chloride, sodium chloride sodium carbonate and lime on the consistency and swelling characteristics of bentonite. The results showed that the increase of the chemical concentration to about 20% of the total sample weight of the mixing water leads to major decrease in the liquid limit and swelling characteristics of the bentonite. The reduction in the swelling of the bentonite is also proportional to the rate of chemical water infiltration into the bentonite. As the increase of the ammonium chloride and lime leads to significant increase of the infiltration.