Groundwater extraction in most Middle East and North Africa (MENA) countries far exceeds its renewability, which ranges from 6% to 100%. Freshwater resources to support food production are very limited in this region. Future climate predictions include more consistent and longer wet periods with increasing surplus rainfall, which will enhance flood and flash flood occurrences in the MENA. Demand management of groundwater resources and managed aquifer recharge (MAR, also called groundwater replenishment, water banking, and artificial recharge, is the purposeful recharge of water to aquifers for subsequent recovery or environmental benefits) represent essential strategies to overcome the challenges associated with groundwater depletion and climate change impacts. Such strategies would enable the development of groundwater resources in the MENA region by minimizing the stress placed on these resources, as well as reducing deterioration in groundwater quality. Groundwater augmentation through recharge dams is a common practice in different countries around the globe. Most dams in the MENA region were built to enhance groundwater recharge, and even the few protection dams also act as recharge dams in one way or another. However, the operating systems of these dams are mostly dependent on the natural infiltration of the accumulated water in the reservoir area, with limited application of MAR. This review presents analyses of groundwater renewability and the effectiveness of recharge dams on groundwater recharge, as well as the potential of MAR technology. This study indicates that the recharge efficiency of dam’s ranges between 15 to 47% and is clustered more around the lower limit. Efficiency is reduced by the clogging of the reservoir bed with fine materials. Therefore, there is a need to improve the operation of dams using MAR technology.

Groundwater constitutes an important part of the available water resources in arid areas. Knowledge of the quantitative and qualitative status of groundwater is a key aspect in optimal groundwater management. The purpose of this study was to provide technical information on the groundwater in the sand aquifer of two neighboring areas in the United Arab Emirates to support stakeholders working towards sustainable groundwater development. The chemical characteristics of the groundwater have been used to identify the processes controlling groundwater chemistry and assess the suitability of the groundwater for agricultural purposes. Despite tapping into the same aquifer, considerable differences in groundwater quality were found between the two study areas. The area with a shallower water table showed clear indications of irrigation return flow deteriorating the groundwater quality. Using standard agricultural indices, the groundwater at both study areas is classified as unfit for agricultural purposes. However, considering that groundwater is the only available water source for irrigation, it will continue to be used for agriculture. This indicates the need for improved irrigation management and the development of new strategies for sustainable groundwater development in arid areas in the context of food security.

Groundwater and harvested rainwater represent the only conventional freshwater resources in the United Arab Emirates (UAE). Groundwater resources in Wadi Al Bih, UAE, are sustainable due to the low exploitation rate for domestic and agricultural purposes. Thus, the groundwater depletion in this area is far less than in other parts of the country. The Wadi Al Bih area is very important for achieving water security in UAE. Therefore, the possible measures of increasing groundwater recharge (e.g., managed aquifer recharge (MAR) methods) are investigated in this paper. The available water resource data were collected, reviewed, validated, and stored in a GIS database. Then, a GIS-based water budget model (WBM) was developed to evaluate the available groundwater resources in Wadi Al Bih and recharge sources. The analyses showed that only 49% of the accumulated rainwater behind the dam is recharging the underlying aquifer. Due to the absence of any direct recharge techniques, the remaining 51% is lost by direct evaporation (15%), and as soil moisture increases in the unsaturated zone (36%), it will subsequently evaporate or percolate depending on the precipitation pattern and air temperature. The results of the WBM indicated that the freshwater resources were decreasing at an alarming rate of approximately thirty-five million cubic meters (MCM) per year until 2019. The groundwater storage and salinity were governed by the rates and patterns of precipitation. For example, the recharge resulting from the two consecutive maximum monthly precipitation events in December 2019 and January 2020 has significantly increased the fresh groundwater reserve and slightly retreated the saline/brackish water toward the shoreline. Moreover, a Mann–Kendall trend analysis was conducted to assess the influence of precipitation, temperature, and evaporation on groundwater recharge. The outcomes suggested that climate variables had a significant effect on groundwater supplies. The mitigation measures include revising groundwater withdrawal rates based on the annual recharge and enhancing recharge using different MAR techniques and dam operation plans.

Fracture systems are of great importance in the field of structural geology. Faults commonly afford easy passage to groundwater and fluids such as hydrothermal fluids and magmas or even contribute to earthquake hazard monitoring. For a geologist, it is not always easy to discern such morphotectonic structures at close range. Both remote sensing techniques and spatial modeling permit the recognition and better understanding of the brittle tectonics in an area. This study was an effort to delineate the tectonic structures on Crete by combining Sentinel-2 satellite data and spatial data. For the enhancement and better discrimination of photolineaments primarily recognized on satellite imagery, a variety of enhancement techniques has been applied. The evaluation of a photolineament as a potential fracture zone was based on several factors: the DEM of the study area, the shaded relief, the slopes and corresponding aspects, the drainage network, the geology and general observations on vegetative coverage appearance. The application of these methods revealed several fracture zones, which we recommend be certified by field investigations. Fault-mapping results may be used for a variety of geological and hydrogeological studies. Indicative places of a large concentration of groundwater are of vital importance for subsequent exploitation by areas of need. The present work may provide useful information for further analysis by geophysicists and seismologists.

The spatial display of clustered data using machine learning (ML) as regions (bordered areas) is currently unfeasible. This problem is commonly encountered in various research fields that utilize clustering algorithms in their workflow. We present in this study an approach utilizing ML algorithm models that can be trained to any specific dataset to produce decision boundaries. These boundaries are overlaid onto the geographic coordinate system (GCS) to generate geographic clustering regions. The proposed approach is implemented in the Python Package Index (PyPI) as a geovisualization library called geographic decision zones (GeoZ). The efficiency of GeoZ was tested using a dataset of groundwater wells in the State of California. We experimented with 13 different ML models to determine the best model that predicts the existing regional distribution (subbasins). The support vector machine (SVM) algorithm produced a relatively high accuracy score and fulfilled the required criteria better than the other models. Consequently, the tested SVM model with optimized parameters was implemented in the GeoZ open-source library. However, it is important to note that limitations in the application of GeoZ may arise from the nature of the SVM algorithm, as well as the volume, discontinuity, and distribution of the data. We have attempted to address these limitations through various suggestions and solutions.