Saltwater intrusion management in shallow and deep coastal aquifers for high aridity regions

Integrated management of groundwater quantity, physicochemical properties, and microbial quality in West Nile delta using a new MATLAB code and geographic information system mapping

Groundwater is an excellent alternative to freshwater for drinking, irrigation, and developing arid regions. Agricultural, commercial, industrial, residential, and municipal activities may affect groundwater quantity and quality. Therefore, we aimed to use advanced methods/techniques to monitor the piezometric levels and collect groundwater samples to test their physicochemical and biological characteristics. Our results using software programs showed two main types of groundwater: the most prevalent was the Na-Cl type, which accounts for 94% of the groundwater samples, whereas the Mg-Cl type was found in 6% of samples only. In general, the hydraulic gradient values, ranging from medium to low, could be attributed to the slow movement of groundwater. Salinity distribution in groundwater maps varied between 238 and 1350 mg L-1. Although lower salinity values were observed in northwestern wells, higher values were recorded in southern ones. The collected seventeen water samples exhibited brackish characteristics and were subjected to microbial growth monitoring. Sample WD12 had the lowest total bacterial count (TBC) of 4.8 ± 0.9 colony forming unit (CFU mg L-1), while WD14 had the highest TBC (7.5 ± 0.5 CFU mg L-1). None of the tested water samples, however, contained pathogenic microorganisms. In conclusion, the current simulation models for groundwater drawdown of the Quaternary aquifer system predict a considerable drawdown of water levels over the next 10, 20, and 30 years with the continuous development of the region.

Provision of Desalinated Irrigation Water by the Desalination of Groundwater Abstracted from a Saline Aquifer

Globally, about 54 million ha of cropland are irrigated with saline water. Globally, the soils associated with about 1 billion ha are affected by salinization. A small decrease in irrigation water salinity (and soil salinity) can result in a disproportionally large increase in crop yield. This study uses a zero-valent iron desalination reactor to effect surface processing of ground water, obtained from an aquifer, to partially desalinate the water. The product water can be used for irrigation, or it can be reinjected into a saline aquifer, to dilute the aquifer water salinity (as part of an aquifer water quality management program), or it can be injected as low-salinity water into an aquifer to provide a recharge barrier to protect against seawater intrusion. The saline water used in this study is processed in a batch flow, bubble column, static bed, diffusion reactor train (0.24 m3), with a processing capacity of 1.7–1.9 m3 d−1 and a processing duration of 3 h. The reactor contained 0.4 kg Fe0. A total of 70 batches of saline water (average 6.9 g NaCl L−1; range: 2.66 to 30.5 g NaCl L−1) were processed sequentially using a single Fe0 charge, without loss of activity. The average desalination was 24.5%. The reactor used a catalytic pressure swing adsorption–desorption process. The trial results were analysed with respect to Na+ ion removal, Cl− ion removal, and the impact of adding trains. The reactor train was then repurposed, using n-Fe0 and emulsified m-Fe0, to establish the impact of reducing particle size on the amount of desalination, and the amount of n-Fe0 required to achieve a specific desalination level.

Assessing the Hazards of Groundwater Logging in Tourism Aswan City, Egypt

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.

Investigation of Groundwater Logging for Possible Changes in Recharge Boundaries and Conditions in the City of Aswan, Egypt

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.