Search

The estimation of reference evapotranspiration (ETo), a crucial step in the hydrologic cycle, is essential for system design and management, including the balancing, planning, and scheduling of agricultural water supply and water resources. When climates vary from arid to semi-arid, and there are problems with a lack of meteorological data and a lack of future information on ETo, as is the case in Egypt, it is more important to estimate ETo precisely. To address this, the current study aimed to model ETo for Egypt's most important agricultural governorates (Al Buhayrah, Alexandria, Ismailiyah, and Minufiyah) using four machine learning (ML) algorithms: linear regression (LR), random subspace (RSS), additive regression (AR), and reduced error pruning tree (REPTree). The Climate Forecast System Reanalysis (CFSR) of the National Centers for Environmental Prediction (NCEP) was used to gather daily climate data variables from 1979 to 2014. The datasets were split into two sections: the training phase, i.e., 1979–2006, and the testing phase, i.e., 2007–2014. Maximum temperature (Tmax), minimum temperature (Tmin), and solar radiation (SR) were found to be the three input variables that had the most influence on the outcome of subset regression and sensitivity analysis. A comparative analysis of ML models revealed that REPTree outperformed competitors by achieving the best values for various performance matrices during the training and testing phases. The study's novelty lies in the use of REPTree to estimate and predict ETo, as this algorithm has not been commonly used for this purpose. Given the sparse attempts to use this model for such research, the remarkable accuracy of the REPTree model in predicting ETo highlighted the rarity of this study. In order to combat the effects of aridity through better water resource management, the study also cautions Egypt's authorities to concentrate their policymaking on climate adaptation. [ABSTRACT FROM AUTHOR]

Climate change (CC) directly affects crops' growth stages or level of maturity, solar radiation, humidity, temperature, and wind speed, and thus crop evapotranspiration (ETc). Increased crop ETc shifts the fraction of discharge from groundwater aquifers, while long-term shifts in discharge can change the groundwater level and, subsequently, aquifer storage. The long-term effect of CC on the groundwater flow under different values of ETc was assessed for the Nile Delta aquifer (NDA) in Egypt. To quantify such impacts, numerical modeling using MODFLOW was set up to simulate the groundwater flow and differences in groundwater levels in the long term in the years 2030, 2050, and 2070. The model was initially calibrated against the hydraulic conductivity of the aquifer layers of the groundwater levels in the year 2008 from 60 observation wells throughout the study area. Then, it was validated with the current groundwater levels using an independent set of data (23 points), obtaining a very good agreement between the calculated and observed heads. The results showed that the combination of solar radiation, vapor pressure deficit, and humidity (H) are the best variables for predicting ETc in Nile Delta zones (north, middle, and south). ETc among the whole Nile Delta will increase by 11.2, 15.0, and 19.0% for the years 2030, 2050, and 2070, respectively. Zone budget analysis revealed that the increase of ETc will decrease the inflow and the groundwater head difference (GWHD). Recharge of the aquifer will be decreased by 19.74, 27.16, and 36.84% in 2030, 2050, and 2070, respectively. The GWHD will record 0.95 m, 1.05 m, and 1.40 m in 2030, 2050, and 2070, respectively when considering the increase of ETc. This reduction will lead to a slight decline in the storage of the Nile Delta groundwater aquifer. Our findings support the decision of the designers and the policymakers to guarantee a long-term sustainable management plan of the groundwater for the NDA and deltas with similar climate conditions. [ABSTRACT FROM AUTHOR]

Lateral saltwater intrusion (LSWI) and vertical saltwater intrusion (VSWI) are the major problems in coastal aquifers. Coastal aquifers are subjected to natural and artificial changes, including sea‐level rise, decreasing inland recharge, and overexploitation of production wells' water resources. Therefore, this study investigates the influence of changing the coastal aquifers boundary conditions considering climate changes' effect. Parameters describing the upward saline well parameters based on the abstraction conditions, also, the top layer properties were studied based on the erosion and sediments, irrigation, and drainage conditions. For this purpose, the SEAWAT model was employed to simulate lateral SWI based on Henry's problem principle. The sensitivity analysis of the mentioned parameters was accomplished considering as a case study the Biscayne aquifer in the Cutler Ridge area near Deering Estate, Florida, USA, where the LSWI and VSWI were also investigated. The results indicate that the boundary conditions, abstraction well parameters, and top layer cost significantly impact aquifer LSWI and water upconing. The simulation results of the Biscayne aquifer for a saline water head of 84.86 cm for 2060 indicate a decrease in freshwater recharge by 30% and increasing the saltwater concentration by 14.30%. At the same time, the LSWI increased by 3.30%, 22.80%, and 8.70%, while the relative upconing heights reached 0.63, 0.60, and 0.47 compared with 0.42 for the current situation. Increasing the upward saline abstraction well discharge rates by 50% increases the LSWI by 9.40%. In contrast, increasing the depth by 10%; decreases the distance by 30%, the screen length by 30%, the LSWI decreased by 1.80%, 25.10%, and 1.30%, respectively. At the same time, the relative VSWI height reached 0.60, 0.39, 0.48, and 0.40, respectively. Moreover, decreasing the top layer hydraulic conductivity by 25% and increasing the aquitards layer depths by 200% decreased the LSWI by 4.90% and 7.80%, respectively. At the same time, the relative VSWI height reached 0.34 and 0.30, respectively. In addition, the saline water heads, a freshwater recharge should be controlled to manage SWI; the upward well should be utilized at a low abstraction rate, far from the seaside, and with minimum screen length. The agriculture activity for decreasing the soil permeability for the top layer must be extended for better management of the SWI. The solution‐oriented findings resulting from this study might be useful for decision‐makers and engineers to develop effective management measures to tackle the SWI issue in coastal aquifers. [ABSTRACT FROM AUTHOR]

This paper studies the groundwater logging problem in the Quaternary aquifer in Aswan city, Upper Egypt. Groundwater levels are already very high in Aswan city, but this has not been exploited, and it causes damage to the environment and infrastructure for roads, building, and templets. Rising groundwater leads to the deterioration and poor quality of agricultural lands. The main objective of this study is to assess and investigate the main reasons for the groundwater logging in the tourist city of Aswan using field investigation during different periods and gain a better understanding of the water dynamics in the study area. This study investigated the surface water levels in the High Dam Lake (HDL), the Kima Lake water levels, the recharge in the fish hatchery, the abstraction well rates in Kima and El-Shalal, and the leakage from the drinking water and wastewater network in Aswan city within the study area using field investigation. The results of this study show that the HDL is one of the most important sources feeding the aquifer in the study area, and it affects the rise and fall of the groundwater levels, but it is not the only factor that affects this problem. Moreover, the rise in the groundwater levels was due to the infiltration from the unlinking fish hatchery, the reduction in abstraction well rates from Kima Lake, the lack of abstraction from El shallal region, the increase in the leakage from drinking water pipelines, sewage networks and septic underground wastewater tanks; these factors are affecting groundwater logging in Aswan city. Potential groundwater level maps for the study area were generated using field data and ArcGIS technique for the years 2010, 2012, 2014, 2017, 2018, and 2020. Based on the results of the potential groundwater maps, the maximum and minimum difference for the groundwater levels in the study area between 2017 and 2012 reached 12.56 m and 0.83 m, respectively; also, between 2018 and 2017, the levels were 4.34 m and 0.25 m, respectively. Moreover, between 2020 and 2018, they were 8 m and 0.38 m, respectively. [ABSTRACT FROM AUTHOR]

Groundwater is of great importance in our daily life, and its importance is due to its multiple uses, whether in agriculture, industry or other uses. Increasing the Groundwater Levels (GWL) in any area is a great benefit for its importance and multiplicity of uses, but in the city of Aswan, it is different, as the increase in the GWL causes severe damage to buildings and leads to poor quality of agricultural land and the destruction of infrastructure due to the lack of good management. The main objective of this study is to develop a conceptual model of the groundwater system to gain better understanding of water dynamics in the study area and to investigate different management scenarios of the use of groundwater. The model was developed using MODFLOW code to achieve the objective of the study, where the necessary field data were collected to feed the model from the study area, such as Surface Water Levels (SWL) in the Aswan Dam lake and the Nile River, GWL in the Aswan Aquifer and the different characteristics of the layers constituting the aquifer, such as porosity and recharge for different periods to ensure obtaining the most accurate and best results from the model. The model was calibrated with mean residual and absolute mean residual which reached −0.08 and 0.629 m, respectively, with a Root Mean Square Error (RMSE) of 0.737m and a normalized RMSE of 4.319%. Two future scenarios have been developed to arrive at a future vision of GWL in the Aswan aquifer. The first scenario investigated GWL in the study area by changing the values of recharge to the aquifer resulting from an increase in the drinking water and sewage networks' leakage values, which were predicted in the future for years 2025, 2030, 2035 and 2040. The GWL in the study area are increasing as a result of the increase in the amount of leakage in the years 2025, 2030, 2035 and 2040 compared to the GWL in the study area for the year 2020 by 0.29%, 1.31%, 2.01% and 3.16%, respectively. The second scenario investigated GWL by changing the water levels in El hebs (the lake between the High Dam and the Aswan Dam) as follows (108 m, 110 m, 112 m, 114 m, 116 m and 118 m), where the groundwater levels were calculated in the Aswan Aquifer corresponding to each level. The percentage of increase in groundwater levels corresponding to the levels 108 m, 110 m, 112 m, 114 m, 116 m and 118 m compared to the groundwater levels at the level of 106 m was found as follows: 0.92%, 2%, 2.87%, 4.05%, 4.91% and 5.67%, respectively. The simulation results are intended to support integrated groundwater modeling for the components of the hydrological water budget in the city of Aswan. Furthermore, the model provides us with a better understanding of long-term scenarios for the waterlogging in the city. The results are useful for managing the water logging problems and planning the future infrastructure in the city of Aswan. [ABSTRACT FROM AUTHOR]

The majority of residential, agricultural, and industrial areas are situated on cohesive soil in the Nile Delta, Egypt. Excessive pumping from the Nile Delta aquifer to meet the increasing demands for water could lead to aquifer system compaction and land subsidence. Land subsidence endangers infrastructure such as buildings, bridges, canals, and roads, as well as deteriorating lands and agricultural resources. The objective of this research is to investigate the land subsidence and predict the future behavior of the middle Nile Delta. The study goals are met by using a numerical model (MODFLOW) to simulate groundwater flow and an analytical solution to calculate land subsidence conditions. In this study, three scenarios are considered including; decreasing aquifer recharge, increasing abstraction and combination of the two. The results reveal that decreasing recharge by 94.4%, 88.8%, and 83.2% led to 30-, 60-, and 90-mm land subsidence, respectively, while increasing abstraction by 146%, 193%, and 233% led to land subsidence by 190, 380, and 560 mm, respectively, in the Nile delta. However, the combination of the two scenarios led to 220-, 440-, and 650-mm land subsidence. According to the results the future land subsidence due to over pumping from the Nile Delta should be considered in the future development plans of the country which intend to increase the abstraction from the Nile Delta aquifer. Increasing abstraction could increase the land subsidence that may cause many damages in different properties. [ABSTRACT FROM AUTHOR]

Canal seepage losses can contribute significantly to groundwater aquifers in arid and semi‐arid regions worldwide. In addition, surface water evaporation and evapotranspiration from adjacent riparian vegetation directly affect surface water availability across these regions. This study aims to evaluate interactions between irrigation canals and the Nile Delta groundwater aquifer in Egypt under four operational scenarios: (i) decreased stream flows in the four main diversion canals associated with upper Nile diversions and climate change, (ii) concrete lining of irrigation canals, (iii) combined lining and use of Photo‐Voltaic (PV) Solar Panel covers on canals and (iv) enclosure of the canals in closed conduits. We investigated the effects of these scenarios on regional groundwater supplies and levels using MODFLOW and water budget analyses. Decreased streamflow (scenario 1) resulted in decreased aquifer recharge (from 732 910 to 483 800 m3 day−1) and lower groundwater levels as compared to the base case (present) conditions. Moreover, groundwater flows from the aquifer to the four main canals noticeably increased from 23 176 to 79 364 m3 day−1. Water budget analyses associated with canal lining scenarios (2, 3, & 4) indicated that canal leakage to the aquifer accounted for 146 582, 146 582, and 73 291 m3 day−1 respectively. The changes in canal efficiencies reached 29.3%, 67.1%, 75.3%, and 91.8% while the changes in aquifer recharge efficiencies were 66%, 20%, 20%, and 10% for the four scenarios, respectively. Overall, we found that canals lining is likely the most suitable solution for managing water resources in the Nile Delta. Further aspects to be considered in future studies include the loss of biodiversity along streams embankments due to channel lining. [ABSTRACT FROM AUTHOR]

The influence of climate change on the availability and quality of both surface- and ground-water resources is well recognized nowadays. In particular, the mitigation of saline water intrusion mechanisms in coastal aquifers is a recurrent environmental issue. In the case of the Nile delta, the presence of sea level rise and the perspective of other human-induced stressors, such as the next operation of the Grand Ethiopian Renaissance Dam, are threats to be taken into account for guaranteeing resilient agricultural practices within the future possible scenarios. Subsurface drainage offers a practical solution to the problem of upward artesian water movement and the simultaneous downward flow of excess irrigation water, to mitigate the salinization in the root zone. Subsurface draining systems can contribute to mitigate the vulnerability to climate change and to the increased anthropic pressure insofar they are able to receive the incremented flow rate due to the foreseen scenarios of sea level rise, recharge and subsidence. This paper introduces a rational design of subsurface drainage systems in coastal aquifers, taking into account the increment of flow in the draining pipes due to future possible conditions of sea level rise, artificial recharge and subsidence within time horizons that are compatible with the expected lifespan of a buried drainage system. The approach proposed in this paper is characterized by the assessment of the incremental flow through the drains as a function of various possible scenarios at different time horizons. Our calculations show that the impact on the discharge into the existing subsurface drainage system under the new foreseen conditions is anything but negligible. Thus, future climate-related scenarios deeply impact the design of such hydraulic structures, and must be taken into account in the frame of the next water management strategies for safeguarding agricultural activities in the Nile delta and in similar coastal contexts. Unlabelled Image • Subsurface drainage helps safeguarding agricultural activities from salinization. • Future climate scenarios deeply impact the design of such hydraulic structures. • Drained flow increased notably for sea level rise, augmented recharge and subsidence. • Artificial recharge can be used to counteract sea water intrusion. • Adversely, artificial recharge also affects the total flow in subsurface drains. [ABSTRACT FROM AUTHOR]

Experimental and numerical models can be used to investigate saltwater intrusion (SWI) in coastal aquifers. Sea level rise (SLR) and decline of freshwater heads due to climate change are the two key variables that may affect saltwater intrusion. This study aims to give a better understanding of the impact of increasing seawater levels and decreasing freshwater heads due to climate change and increasing abstraction rates due to overpopulation using experimental and numerical models on SWI. The experimental model was conducted using a flow tank and the SEAWAT code was used for the numerical simulation. Different scenarios were examined to assess the effect of seawater rise and landside groundwater level decline. The experimental and numerical studies were conducted on three scenarios: increasing seawater head by 25%, 50% and 75% from the difference between seawater and freshwater heads, decreasing freshwater head by 75%, 50% and 25% from the difference between seawater and freshwater heads, and a combination of these two scenarios. Good agreement was attained between experimental and numerical results. The results showed that increasing the seawater level and decreasing freshwater head increased saltwater intrusion, but the combination of these two scenarios had a severe effect on saltwater intrusion. The numerical model was then applied to a real case study, the Biscayne aquifer, Florida, USA. The results indicated that the Biscayne aquifer is highly vulnerable to SWI under the possible consequences of climate change. A 25 cm seawater rise and 28% reduction in the freshwater flux would cause a loss of 0.833 million m3 of freshwater storage per each kilometer width of the Biscayne aquifer. This study provides a better understanding and a quantitative assessment for the impacts of changing water levels' boundaries on intrusion of seawater in coastal aquifers. [ABSTRACT FROM AUTHOR]

Saltwater Intrusion (SWI) in many coastal areas is accelerated by freshwater boundary changes due to over-pumping and decreasing aquifer recharge and sea-level rise. This study aims to control SWI due to the rise in sea levels in three climate regions: (i) humid and wet regions using storage dams at different heads and recharge ponds, (ii) hyper-arid and arid regions using physical barriers and wastewater treatment aquifer, brackish water abstraction, and desalination (TRAD) method, and (iii) semi-arid and semi-humid regions using a combination of flooding water recharge well-field and cut-off wall. The study was developed using the world benchmark problem of Henry's problem and Biscayne aquifer in the Cutler Ridge area near Deering Estate, Florida, USA. The finite-difference code SEAWAT was used in numerical simulations. The numerical results indicated that increasing the artificial recharge lake capacity minimizes the SWI in humid and wet regions with a high level of flooding. Moreover, the intrusion is mitigated using physical barriers and the TRAD method for hyper-arid and arid regions. Combining physical barriers during dry seasons and recharge wells for wet seasons resulted in suitable measures to managed the SWI in semi-arid and semi-humid regions. Finally, the best strategy to mitigate the SWI and minimize the desalination costs depends on the precipitation rates. Therefore, the methodology applied to this study represents a valuable tool in order to select the best method based on the climate conditions and particularly the precipitation intensity to increase the water budget in freshwater aquifers. • Freshwater boundary changes due to over-pumping accelerate Saltwater Intrusion. • 6.26% reduction in salinity was achieved using a recharge pond. • Cutoff wall and subsurface dam reduced the Saltwater intrusion 4.1 and 5.1%, respectively • TRAD method reduces salinity up to 9.17% in hyper-arid and arid regions. [ABSTRACT FROM AUTHOR]

Owing to the potential negative impacts of climatic changes and the grand Ethiopian renaissance dam, water scarcity has become an urgent issue. Therefore, the Egyptian Ministry of Water Resources and Irrigation has started a national project of the lining and rehabilitation of canals, to reduce seepage losses and for efficient water resource management. This study presents a new approach for assessing three different lining and crack techniques for the Ismailia canal, the largest end of the river Nile, Egypt. A 2-D steady state seep/w numerical model was developed for the Ismailia canal section, in the stretch at 28.00–49.00 km. The amount of seepage was significantly dependent on the hydraulic characteristics of the liner material. The extraction from aquifers via wells also had a considerable impact on the seepage rate from the unlined canals; however, a lesser effect was present in the case of lined canals. The concrete liner revealed the highest efficiency, followed by the geomembrane liner, and then the bentonite liner; with almost 99%, 96%, and 54%, respectively, without extraction, and decreasing by 4% for bentonite and geomembrane liners during extraction; however, the concrete lining efficiency did not change considerably. Nevertheless, the efficiency dramatically decreased to 25%, regardless of the lining technique, in the case of deterioration of the liner material. The double effect of both deterioration of the liner material and extraction from the aquifer showed a 16% efficiency, irrespective of the utilized lining technique. [ABSTRACT FROM AUTHOR]

Groundwater is considered to be an important water supply for domestics, industry, and irrigation in many areas of the world. Renewable groundwater is recharged by rainfall and seepage from canals and open drain networks. Agricultural and industrial drainage, as well as domestic drainage, represent the main discharges into open drains. Therefore, these drains are considered to be a source of recharge as well as a source of pollution. In this study, we aim to evaluate the impact of the Bahr El Baqar drain system on groundwater quality in the Eastern Nile Delta, Egypt. MODFLOW was used to create a numerical model to simulate groundwater flow in an aquifer and MT3DS was used to simulate solute transport from the open contaminated Bahr El Baqar drain to the groundwater. Two approaches were developed in the study area. The first approach was applied to investigate the impact of increasing the abstraction rates on the contaminant transport into the aquifer, the second approach was developed to identify the effect of lining the drain using different materials on contaminant extension in the aquifer to protect groundwater quality in the east Nile Delta Aquifer. The results showed that the TDS values increased by 18.23%, 23.29%, and 19.24% with increased abstraction rates of 15%, 34%, and 70%, resulting from population increases in 2010, 2025, and 2040, respectively; however, the TDS in the aquifer decreased from 0.6%, to 6.36%, 88.35%, and 90.47% by using lining materials. [ABSTRACT FROM AUTHOR]

Groundwater contamination due to saltwater intrusion (SWI) has an extreme effect on freshwater quality. Analytical and numerical models could be used to investigate SWI. This study aims to develop an analytical solution to investigate SWI into coastal aquifers which was applied to a real case study at the Middle Nile Delta aquifer (MNDA). The study presented a new formula to predict the difference in depth of freshwater to seawater interface due to a change in boundary conditions. A Computer Program for Simulation of Three-Dimensional Variable-Density Ground-Water Flow and Transport (SEAWAT) is used for groundwater flow simulation and SWI and the results compared with the developed analytical solution. Four scenarios are considered in the study, including; the sea-level rise (SLR), reduction in recharge, over abstraction, and combination after 50 years (2070). The analytical solution gave good results compared to the numerical one where Equiline 1 intruded to 103 and 101.66 km respectively at the base case. The results also gave a good agreement between numerical and the analytical solution for SLR due to climate changes by 52.80 cm where the Equiline 1 reached to 105 and 103.45 km. However, the reduction in aquifer recharge by 18.50% resulted in an intrusion for the Equiline-1 to 111 and 108.25 km from the shoreline. Over pumping due to the increase in population by 89% has increased the SWI to reach 121,110.31 km, while it reached 131 and 111.32 km at a combination of the three scenarios, which represents the highest threatening scenario. Also, the difference between the two solutions reached 1.30%, 1.48%, 2.48%, 8.84%, and 15.02%, respectively for the base case and four scenarios. For the current case study, the analytical model gave good results compared to the numerical one, so that the analytical solution is recommended for similar studies, which could save the time and capabilities of computer required for the numerical solutions. [ABSTRACT FROM AUTHOR]

Changes in riverine hydrography and reduced aquifer recharge due to projected climate changes in arid and semi-arid regions are the main issues of water supply, especially in the Nile Delta, Egypt. Continuous degradation results from reduced Nile water flow, poor management of groundwater extraction, and human activities throughout the Nile's course and drainage channels. Contamination of this water with heavy metals and dissolved organic solids reduces the quality of this water, which increases the price of treatment. River Bank Filtration (RBF) is a water treatment technology used for improving the quality of drinking water taken from polluted rivers where abstraction wells are installed on the banks. This study was applied to the RBF site at Embaba, Nile Delta, Egypt using the numerical code MT3D. The study was simulated and calibrated for the current situation and number of scenarios to investigate the effect of climatic changes on RBF sustainability. Four scenarios were simulated to identify and estimate the RBF portion and the total water travel time from the river to the wells. The first scenario involves a reduction in river stages, the second a decrease in aquifer recharge, the third a combination of the first two scenarios, and the fourth scenario combines scenarios 1, 2, and 3. The results indicate that the RBF portion decreased from 67.42% in the base case to 35.46% and 64.99% with a reduction in river stage by 75% from the base case and a decrease in aquifer recharge from 182.50 (base case) to 50 mm per year, respectively. Moreover, the RBF portion increased to reach 87.75% with a reduction in the General Head Boundary of 75% from the base case, while the combination of the three scenarios decreased the RBF portion to 67.24%. Finally, the water supply systems in arid and semi-arid regions should be extended by installing and operating RBF facilities to manage the negative effects of climatic change through reduction in river stages and aquifer recharge, and increasing abstraction due to overpopulation. [ABSTRACT FROM AUTHOR]

Evaluating water quality indicators is a crucial issue in integrated water resource management, since potable water is an essential resource for the world's health and sustainable development. The current study was developed using a coupled model of MODFLOW and MT3DMS (Mass Transport 3-Dimension Multi-Species) to integrate two water supply systems, surface water (polluted drains and canals) and ground water, to identify the contamination process of the groundwater from drains as fresh water is polluted and the contamination level exceeds the standard limits. The study was applied to two cases: the first was a hypothetical simulation and the second was the real case of the Nile Delta Aquifer (NDA). Four different scenarios were simulated to first identify groundwater contamination by total dissolved solids (TDS), and then select the more efficient protection process. The first scenario involved changing polluted drain and canal boundary conditions regarding head and concentration; the second consisted of studying the location of the polluted drain in a low permeability layer or a confined aquifer; the third was based on installing a cut-off wall in the polluted drain sides; and the fourth investigated the use of lining materials for polluted drains. The results reveal that aquifer contamination was decreased by increasing the water head of canals by 50 cm and decreasing the drain head by 50 cm and concentration by 25%, whereby large quantities of groundwater were protected. The percentages of salt repulsion in the hypothetical case were +10.66, +12.89, and +24.99%, while in NDA they were +6.29, +8.71, and +25% respectively compared with the base case. Decreasing the aquifer hydraulic conductivity led to decrease in aquifer contamination, in which the confined aquifer pollution was less than the unconfined aquifers due to the clay cap, which plays a significant role in minimizing the solute transport into the groundwater reservoir, and to reduction of the aquifer salt variation by +19.01% for the hypothetical case. The results indicate that the cut-off wall is effective for contamination management in shallow aquifers (hypothetical case) and the reduction in aquifer salt was +28.49%, whereas it had no effect in the deep aquifer (NDA), where the salt was reduced by just +0.34%. Using the drain lining scenario prevented contamination from the polluted drains and protected the freshwater in the aquifer, so that the aquifer salt mass reductions were +91.02 and +70.13% for the hypothetical case and NDA respectively, indicating that this method is more effective for controlling groundwater contamination. Polluted drains should be located in a low permeability layer to minimize the water degradation. This study represents a new contribution to groundwater protection techniques by changing the boundary conditions, installing a cut-off wall and using linings for polluted drains, and shows the way forward for the future treatment of polluted stream networks. [ABSTRACT FROM AUTHOR]

Stability of canals slopes are of paramount importance in engineering works due to its interaction with the infrastructure including roads networks and buildings. The failure of these slopes could cause human disaster, catastrophic environmental, and economic losses. The present study aims to investigate the stability of canals slopes considering the climate changes through sea level rise, fluctuation of groundwater level and the seismic actions. The study was simulated on the North Eastern part of Nile Delta aquifer, Egypt using the finite difference code of Visual MODFLOW. Moreover, the groundwater flow under the effect of sea level rise was investigated to study its effect on slope stability of El-Salam Canal, Egypt. Furthermore, the finite element program of Phase 2 was implemented, and safety factors were calculated using the shear strength reduction method (SSRM). The models are calibrated and verified through experimental work using permeability and seepage model. Moreover, the two models were applied on El-Salam Canal considering three scenarios to identify the safety factors including the effect of sea level rise (SLR), earthquake acceleration and a combination of the two scenarios. The results indicated that dynamic response values of the canal slope have different variation rules under near and far field earthquakes. Finally, the damage location and pattern of the slope failure are different in varying groundwater conditions. [ABSTRACT FROM AUTHOR]