Abstract
Saudi Arabia depends on underground water resources as the main conventional supply of fresh water. However, recent revelations indicated that shortage of water resources remains the main problem that Saudi Arabia faces as a nation. In this regard, the process of identifying zones or areas that have groundwater potential can help to improve the availability of fresh water. The analysis involves an evaluation of water resources, including the utilization of GIS and remote sensing equipment in previous research papers to identify the underground water probable zones areas in KSA. The study divides the entire Saudi Arabia in five regions namely northern, central, western, southern, and eastern so as to evaluate and indicate the underground water prospective areas in an effective and clear manner. The northern region (Al Jouf, Tabur, Hail, and Al-Qassim), Saq, and overlying aquifers play an essential role in supply water in Saudi Arabia. About 17.90% of the total area of the region became identified as a groundwater potential zone. Based on geomorphological factors, the Wadi catchment areas act as the best appropriate regions for rejuvenation in the northern area. Regarding the central region (Al-Riyad province), about 1.47% and 4.15% may be categorized as exceptional and very good while 12.59%, 74.82%, and 6.97% may receive classifications of good, poor, and very poor underground water probable area. The precincts are primarily situated within the carbonate-sulfate foundations that spread to the Lower Cretaceous from the Lower Jurassic, as well as the sandstone aquifers. In the western area (Wadi Yalanlan basin), the lower regions of the Wadi Yalamlambasin remain as the most encouraging ones for underground water availability and has high and modest probable areas. On the same note, high underground water potential zones can be found on the northern side of the central dyke region surrounding Abu Helal’s farm. The southern area (Jazan region) indicated that 50.5% and 31% contain excellent and good groundwater potential areas while 16% and 2.5% regions showed moderate and poor or unsuitable groundwater potential zones. The eastern region had characteristics of extreme arid and desert environments. Based on the features, the area did not contain any groundwater potential zone. The current evaluation of groundwater potential areas in Saudi Arabia can serve as a significant tool for efficient groundwater resource management.
Contents
2.1. Search Strategy and Scholarly Sources
2.2 Inclusion and Exclusion Criteria
3.3 Geology and Hydrogeological Framework
4. Water Resources in Saudi Arabia
5. Groundwater Potential Zones
5.1 Northern Region (Al Jouf, Tabuk, Hail, andAl-Qassim)
5.2 Central Region (Al-Riyadh Province)
5.3 Western Region (Wadi Yalamlam basin)
5.4 Southern Region (Jazan region)
Introduction
Water resources, including underground water play an essential role in providing fresh water for drinking, irrigation, and industrial activities. However, increased extraction of underground water from the various alluvial aquifers makes them susceptible to pollution-related activities from anthropogenic sources that restrict its availability (Ahmed et al., 2015). Additionally, unavailability of underground water arises from the limited resources, scarce rainfall, and high evaporation rates due to extremely high temperatures. The factors make Saudi Arabia remain as one of the driest nations in the globe. Equally, the issues associated with speedy industrial development and agronomic improvements have played a crucial role in creating unmanageable underground water abstraction and decline in water quality decline in the country (El-Hames et al., 2011). Climate change has created challenges in Saudi Arabia, which have made it hard for the administration to control the scarce water sources. Indeed, the utilization of underground water acquired from aquifers located deep in the ground contributes to the depletion of water sources that have taken hundreds of years to amass and from which the present yearly precipitation has no instantaneous impact (Mahmoud & Alazba, 2014). Based on limitations mentioned regarding water sources and the possible expansion of areas under farming, it becomes appropriate to earmark underground water potential regions. The process provides room for the assessment of water resources and identification of underground water potential areas in Saudi Arabia. Additionally, the use of RS and GIS remain the most advanced techniques utilized for the exploration of earth’s resources, mapping, and administration (Mahmoud & Alazba, 2014). In dry areas, underground water plays an essential role in various development engagements. The procedures involved in groundwater exploration utilize satellite data to monitor underground water storage variations (Mahmoud & Alazba, 2014). Furthermore, GIS operates an important gadget where encrusted data obtained from various thematic charts require quick integration in order to identify groundwater potential precincts.
Many researchers have used RS and GIS technologies since the gadgets are useful in the hydrogeology field. Furthermore, various authors have dealt with the area of identifying underground water probable areas using RS and GIS methods (Mahmoud & Alazba, 2014). Recently, researchers have successfully made efforts to demarcate possible underground water areas using RS data. In more recent times, various investigations revealed probable underground water zones through the use of GIS and empirical techniques for recharge assessment (El-Hames, Al-Ahmadi, & Al-Amri, 2011). In general, in arid areas and specifically those in the western zone of Saudi Arabia, some scholars have studied underground water resources in the past few years. Indeed, a GIS tactic regarding the analysis of underground water purity levels in Wadi Rabigh succeeded due to researchers’ hard work and determination. Mahmoud and Alazba (2014) discovered groundwater presence in shallow dry area aquifers using GIS method in Hada Al-Sham. The issue of underground water potential demarcation using remote sensing and GIS evidence from Wadi Yalamlam catchment area and Makkah Jurisdiction in west KSA succeeded because of the researchers’ resilience, who claimed that the chief aquifer in the region contained alluvial deposits (Mahmoud & Alazba, 2014). Equally, the authors introduced hydrogeological susceptibility and pollution risk map for Al-Qassim, Al-Jouf, and Tabuka aquifers using GIS techniques in northern Saudi Arabia. Pinto, Shrestha, Babel, and Ninsawat, (2017) did a good work in this area so as to assess the prospective artificial underground water rejuvenation areas. The authors utilized GIS and RS to determine the underground water probable regions in the Bojnourd basin located in the NE of Iran while using GIS, RS data, and a probabilistic tactic. In recent times, Pinto et al. (2017) and Mohammadi-Behzad et al. (2018) utilized RS and GIS methods to demarcate underground water probable areas in Azraq Basin in Central Jordan and Leylia-Keynow watershed, southwest of Iran respectively. However, various studies performed reveal different groundwater potential regions for the different zones in Saudi Arabia but integrated research work associated with the whole country does not exist.
Based on the current situation, the study focuses on the state of water rich areas in Saudi Arabia and to evaluate the groundwater potential areas in the country by reviewing the existing studies. The paper’s contribution involves the assessment of related studies in Saudi Arabia and offers information about the various groundwater potential areas in the nation (Zeng, Cui, Liu, Cui, & Wang, 2006). Indeed, the aim of the study revolves around discussions regarding water resources in KSA. Additionally, the main goal of this research is to evaluate and present a cohesive approach of utilizing RS and GIS techniques to pinpoint and delineate underground water potential areas of the different regions (northern, central, western and southern region) of the nation. The research will assist policy-makers and officials in the water resources departments in KSA to engage in appropriate expansion approaches and utilization of both surface runoff and underground water sources (Zeng et al., 2006). Therefore, the approaches will help to eliminate water scarcity and improve water utilization practices such as irrigation.
2. Methodology
The subject associated with groundwater issues is profoundly interdisciplinary. As such, this assessment encompasses the consideration of the expansive assortment of reading resources, such as environmental sciences, geological science, GIS, and remote sensing. The review involves the integration of technical and social standpoints (Pinto et al., 2017). Accordingly, the definition of assessment and methods used in the study indicated the problems that the researcher sought to address, search approaches to access the right articles and related study materials from the various related sources, inclusion and exclusion criteria for pinpointing appropriate journals and booklets, as well as evaluation protocols.
2.1. Search Strategy and Scholarly Sources
The process of assessing areas covered and linked to the topic “groundwater potential zone” allowed the researcher to perform an expansive exploration of the literature. Indeed, the search process aimed at identifying the relevant studies associated with groundwater, remote sensing, and GIS. Equally, the utilization of standard search approaches involved inquiring some significant academic materials extracted from electronic databanks. A systematic search using keywords, such as “water sources,” “groundwater,” “potential zones,” “GIS,” “remote sensing,” and “Saudi Arabia” assisted in finding reliable sources (Zeng et al., 2006). The keywords played an essential role in the search process for various categories of journals’ key terms, abstract, and title in order to exact some preliminary insights into the area of concentration due to the limitations linked to the overreliance on the keyword strategy (Al-Shabeeb, Al-Adamat, Al-Amoush, & AlAyyash, 2018). The articles chosen were analyzed in order to pinpoint the probable groundwater regions in KSA.
2.2 Inclusion and Exclusion Criteria
The use of fundamental questions from current and preceding studies or outcomes from scientific examinations regarding groundwater was employed to further choose the appropriate documents, especially journals for reading. Initially, the choice coincided with the review purpose. The researcher focused on the documents that gave conclusive primary evidence from an efficient point of assessment. Although specific procedural guiding principles were viewed as crucial to ensure the significance of the assessment, the process followed the appropriate steps in order to permit flexibility in the use of the projected tactic to address the importance of investigation in the blossoming area of water resources and groundwater (Pinto et al., 2017). The whole idea focused on the significance of accumulating a relatively complete collection of the appropriate literature. Whatsoever, in order to ensure effective results, journals that failed to meet the set standards in relation to aspects of applicability to the study were ignored. Indeed, each of the published article assessed had the necessary information, including review of the objectives. Moreover, based on abstract review, the assessment focused on the citation and abstract contents to determine their relevance to the interdisciplinary review. The process ensured the consistent utilization of the inclusion and exclusion benchmarks, as well as the resolving of inclusionary differences through re-reviews. The procedure allowed the researcher to perfect and condense the scope of study (Al-Shabeeb et al., 2018). The exclusion encompassed the use of explicit conditions in relation to the value of the research topic, including the process of identifying adequately searched and applicable information. The researcher attempted various approaches in the beginning of the literature progress in order to broadly read about the topic and improve the comprehension of the field.
3. Study Area
3.1 Location and Climate
Located in the arid region in the Middle East, KSA lies on the north of the equator and east of the Greenwich meridian. Indeed, the nation’s total area is 2,149,690km2 (830,000 sq mi), which makes it the globe’s 13th biggest nation. Based on the sizes of the other countries in the Arabian Plate, it is geographically the biggest in the region. The Arabian Desert dominates the country’s geography, which is associated with semi-desert, shrub land, and numerous mountain ranges and highlands. The country has a few lakes but does not have permanent rivers. However, apart from the Asir Province located in the southwestern region, KSA boasts of a desert climate associated with high temperatures during daytime and low temperatures in the night. In this case, normal summer temperatures reach about 45°C and up to a high of 54°C. During the winter season, temperatures do not drop below the 0°C mark. Equally, during the seasons of autumn and spring, the warmth remains moderate and temperatures recorded average 29°C (Al-Shabeeb et al., 2018). Additionally, yearly rainfall is considerably low. Indeed, the Asir zone has different climatic conditions associated with the influence of the Indian Ocean monsoon winds, which occur in the months of October up to March. In this regard, an average rainfall of up to 300mm takes place in this period, which constitutes approximately 60% of the yearly rainfall in KSA.
3.2 Topography
The central plateau represents the main topographical feature, which arises from the Red Sea’s coastline and progressively slopes towards the Nejd in the direction of the Persian Gulf. Along the coast of the Red Sea, Tihamah parallel, a thin coastal plain, runs a daunting escarpment. In addition, Asir Province has mountains, including Mount Sawda (3,133m), the highest one in KSA. On the side of the peninsula, people can see the Great Rift fault and escarpments that run along the Red Sea sandwiched between the Gulfs of Aqaba and Aden (Al-Shabeeb et al., 2018). Regarding the escarpment, its eastern side slope remains comparatively placid and drops to the visible shield of the prehistoric landform in place prior to the occurrence of the faulting process. A second and lower elevation, the Jabal Tuwayq, starts from northern side to the south via the Riyadh area. Subsequently, within the southern part, the Tihamah, a coastal plain landmass, rises progressively towards the mountains from the sea. Equally, Hejaz spreads towards the south to the boarders of the mountainous Yemen region. Najd, the centrally placed plateau, spreads east towards the Jabal Tuwayq region and afar. Ad Dahna, an extensive thin elongation of desert splits Najd from the eastern zones of KSA, which elevates towards the east to the Persian Gulf’s sandy coastline (Pinto et al., 2017). In the northern part of Najd lies a specifically bigger desert, An Nafud, which separates the “heart of the peninsula” from the prairielands region situated in northern part of Saudi Arabia. The Rub al Khali in southern Najd remains as one of the biggest sand deserts in the universe.
3.3 Geology and Hydrogeological Framework
The Arabian Peninsula contains two major geologic units, including the eastern region that consists of progressively thickening Phanerozic sedementary classification that emerges from the western part towards the east and identified as the Arabian Platform. The other one represents the western part that comprises Pre Cambrian underground rocks regarded as the Arabian shield (Al-Shabeeb et al., 2018). From the analysis, the Saq Sandstone lies in the bottom of the alluvial sequence that emerges from a strip uncomfortably overlying the basement. Indeed, the superimposing creations appear one after another in a sequential order and move far away from the contact with the bottom ground in the eastern direction (Zeng et al., 2006). In addition, the Cambro-Ordovician Saq creation that comprises majorly of moderate to uneven sandstones, which range in breadth from 400-928 meters, creates the main aquifer structure in KSA.
The area of focus associated with the research is represented by the multifaceted aquifer structure with the Saq creation remaining the highly renowned source of extensive water resource (Zeng et al., 2006). Based on the thickness, water quality and the category of aquifer (restricted or unconstrained), as well as hydraulic features, other aquifer units become exposed. In this regard, individual farmers can meet their water needs for small-scale farming practices where they can drill wells that range from 100 to 150 meters in depth in order to tap the various geological formations. Overall, there are eight principal (Neogene, Damman, Umme Er Radhuma, Biyadh and Wasia, Minjur and Dhruma, Tabuk, Wajid and Saq) and nine secondary (Wadi sediments, Basalts, Aruma, Lower cretacccous, Sakaka, Upper Jurassic, Al-Jilh, Al-Khuf and Al-Jouf) aquifers or aquifer sub-groups found in KSA (Pinto et al., 2017). Majority of the aquifers are explored in areas where they appear in the unrestricted states.
4. Water Resources in Saudi Arabia
Prior to the 1980s, KSA had lakes located at Layla Aflaj and deep ponds situated at Al-Kharj and supplied by enormous subsurface aquifers formed during ancient times. The underground water sources are non-renewable. In this case, Al Kharj represented a treasured spring that supplied drinking water located in a unproductive area. In the recent past, the aquifers have supported many activities, including domestic and agricultural purposes (Selvam et al., 2016). Currently, no water remains in the lake sites or waterholes.
Without all-season rivers or other sources of fresh water, including streams and underground water, purified sea water and the scarce surface runoff water remain as the only means of supplying the country’s water needs. Irrespective of the water challenges in KSA, the eastern region and Jabal Tuwayq have plenty of artesian wells and springs. Equally, Al Ahsaa has a large number of reliable pools regularly refilled by artesian springs due to the availability of groundwater that comes from the eastern water catchment area of the Jabal Tuwayq. The wells and springs enable expansive irrigation activities in areas around the local oases (Al-Shabeeb et al., 2018). The Hijaz represents a region that boasts of springs and wells that come from the hilly zones. Furthermore, in Najd and the great desert areas, water points become relatively dispersed over huge areas and fewer. In this regard, the use of appropriate mechanisms such as hoisting or pumping enables people to bring water to the surface. In areas with plenty of water, its quality becomes an issue. Saudi Arabia records approximately 158.47 billion m3 of rainfall water per annum (Selvam et al., 2016). On the same note, the estimates of the overall reserves situated in the sedimentary deposits stands at 84 billion m3 in one of the biggest lone sedimentary basin within Saudi Arabia (Mohammadi-Behzad et al., 2018). Indeed, the aggregate amount of underground water removed from underground water sources in Saudi Arabia within the past 20 years is approximately 254.5 billion m3, which met the needs of the residents and utilization in areas under irrigation (Selvam et al., 2016). Irrespective of the amount of water withdrawn from the underground water sources, the recharge over the last two decades could not surpass the 41.04 billion m3 mark (Al-Shabeeb et al., 2018). Furthermore, the non-renewable underground reserve is estimated to contain 259.1-760.6 billion m3 with an efficient yearly recharge of 886 million m3. Regarding the total internal renewable water, it stands at approximately 2.4 billion m3 per annum whereas 1.4 billion m3 of surface run off is collected by 302 dams located in various regions of the country each year (Zaidi et al., 2015). The country’s administration necessitates the production of an estimated 1.06 billion m3 of desalinated water per annum. On the same note, the waste water treatment plants treat about 0.73 billion m3 per year of domestic waste water. Contemporary technology has enabled people to locate underground water in order for them to exploit it for domestic and industrial purposes (Selvam et al., 2016). Saudi Aramco’s (a Saudi Arabian Oil Firm) experts have discovered deep aquifers in various parts of northern and eastern KSA. Indeed, the technicians established that the Wasia, the biggest underground water point in KSA has more water as compared to the Persian Gulf. In this regard, the Saudi Administration, the United Nations (UN), and Saudi Aramco, as well as Food and Agricultural Organization (FAO) have established individual and combined efforts to explore groundwater resources (Mohammadi-Behzad et al., 2018). Irrespective of the joint efforts, Saudi Arabia meets its citizens’ water needs through the various waters sources, such as non-renewable and renewable groundwater, desalinated water, renewable surface water, and treated waste water.
5. Groundwater Potential Zones
The current research classifies the entire Saudi Arabia into six areas (northern, eastern, central, western, southern and, empty quarter region) so as to assess the underground water prospective zones. The classification of the regions relied on the geological, hydrological, and meteorological features. Indeed, the analysis identifies the eastern and empty quarter areas as ones that represent extreme desert environments. As such, the two regions did not have significant groundwater zones.
5.1 Northern Region (Al Jouf, Tabuk, Hail, andAl-Qassim)
The northern region comprises three provinces (Al Jouf, Tabuk, Hail and Al-Qassim) of Saudi Arabia. In this zone, the Cambro-Ordovician Saq establishment comprises moderate to abrasive sandstones that range from 400-928 m in thickness and creates the main aquifer structure in northern KSA (Mohammadi-Behzad et al., 2018). The region boasts of seven underground water sources arranged from the lowest point to the top namely Saq and Kahfah granites (Qassim Formation); Quwarah (Qassim Formation) to Sarah granites (TabukFormation); Sharawra (Qalibah formation), as well as Tawil granites. The others include Jubah granite; Khuff limestone, and Secondary (Mesozoic), which is tertiary to Quaternary (STQ) granite, as well as limestone (Mohammadi-Behzad et al., 2018). The area also contains two layers (Jouf limestone and granite and Unayzah and Berwath granites) that act provincially as aquitards but comprise units locally explored as underground water sources. Indeed, the Saq aquifer creates the most noteworthy water source although other groundwater points play an essential role in increasing water supply in the country. In addition, the water table level ranges from 500-838 m above the sea level. In this region, the underground water flow comes from the south to north. Issues associated with the high levels of groundwater abstraction affect the Qassim region (Selvam et al., 2016). Based on long-term analysis of the water cycle, precipitation is regarded as the main key for reviving underground water. The water infiltrates through top soils into the underground bedrocks and lastly finds its path to the underground water catchment area.
Zaidi, Nazzal, Ahmed, Naeem, and Jafri (2015) did a wonderful job in identifying the potential groundwater regions. In their work, thematic maps of the numerous considerations, including vadose zone, soil texture, breadth, slope, the quality of underground water, and type of water bearing establishment were incorporated in GIS through the use of Boolean logic to categorize the potential groundwater areas in Northwestern Saudi Arabia. The aspect of land utilization or land cover diagram assisted to filter maps and to elude municipal and agrarian zones (Zaidi et al., 2015). After generating the various layers of distinct constraints through the use of Boolean binary rationality (0 representing inappropriate areas and 1 the appropriate regions), the use of an efficient operator helped to incorporate all thematic covers to produce the last possible AGR areas. Lastly, a proximity assessment was performed on the basis of the closeness of the recognized potential groundwater area. About 17.90% of the entire area (Al Jouf, Tabuk, Hail and Al-Qassim) was earmarked as the potential underground water recharge zone without the consideration of land utilization or land area patterns (Zaidi et al., 2015). The incorporation of land utilization and suitable recharge zones were identified as representing 14.24%. While considering the geomorphic elements, it became clear that Wadi catchments were the most appropriate for groundwater zone while the sand dune areas had the lowest potential for groundwater. Indeed, because rainfall in the area is low, artificial recovery of underground water cannot rely only on precipitation (Zaidi et al., 2015). Therefore, supplementary sources, including excess desalinated seawater and treated waste water can act as potential sources of recharging underground water in this area.
5.2 Central Region (Al-Riyadh Province)
The central region (Al-Riyadh Province) represents the second biggest jurisdiction in Saudi Arabia. In this zone, the highest temperatures average 42.6 °C in July. However, winter seasons have warm days and relatively cold and windy night periods. Moreover, the average monthly humidity levels range from 15%-51% during the summer and winter seasons respectively (Selvam et al., 2016). Indeed, the mean yearly moisture levels stand at 32.5%. The region’s general climate is considered as arid and the metropolitan area receives yearly rainfall that ranges from 41-230 mm. As a way of ensuring underground water rejuvenation and rainwater collection, the administration oversaw the construction of fifty-seven dams in the area. Many areas of the central region have good slopes and showcase intensively cultivated parts. Arenosols and Lithosols are the major soil types in the area. Based on structural analysis, the main lithological structures include carbonate stones, mixed alluvial consolidated rocks, and alluvial deposits (Mohammadi-Behzad et al., 2018). The central region’s location has carbonate-sulfate creations that spread to the Lower Cretaceous and the granite aquifers from the Lower Jurassic.
A groundwater modeling analysis done using GIS and remote sensing identified underground water probable areas in Saudi Arabian central region. In this case, the study utilized RS and GIS-related decision provision structure in the identification of underground water potential areas in this section (Zeng et al., 2006). Based on this research, nine conditions were chosen for identifying and mapping GWP areas. The features are expressed in relation to the various thematic covers, namely: the type of soil, land cover utilization (derivative of the existing RS data), slope (landscape), lithology, precipitation, geological construction, geomorphology, lineament concentration, and drainage compactness. As such, the various approaches used in generating groundwater potential area map were executed in an appropriateness model created using the model builder of ArcGIS (Zeng et al., 2006). Indeed, the appropriateness model creates appropriate maps for GWP region in relation to the incorporation of the numerous thematic charts such as the type of soil, land utilization, and land cover, lithology, slope, precipitation, geological construction, geomorphology, lineament concentration, and drainage compactness while utilizing the Weighted Overlay Process (WOP), as well as using both raster and vector databanks. In relation to AHP scrutiny and considering the nine thematic aspects, the 3-D ranges of GWP area were acknowledged with the use of multi criteria evaluation (MCE). Equally, the appropriateness model produced a GWP chart with five appropriateness classes (El-Hames et al., 2011). The final result revealed that 1.47 % and 4.15% representing 5608.5 km2 and 15,787.3 km2 respectively of the region under review was categorized as exceptional and good correspondingly, and 12.59 %, 74.82%, and 6.97% representing 47,911.1 km2, 284,670.9 km2 and 26,519.9 km2 respectively of the zone were categorized using the latter classifications respectively.
The spatial dispersal of the underground water prospective regions of the central zone indicated that ‘excellent’ groundwater potential areas were within Wadi networks located the various areas of Al-Riyadh province (Mohammadi-Behzad et al., 2018). As such, the analysis establishes that water supply of Riyadh originates from the shallow underground water sources in the Wadi waterways and the karst groundwater sources linked with the carbonate-sulfate establishments, which spread to the Lower Cretaceous and the granite underground water sources of Minjur and Wasia formations from the Lower Jurassic.
5.3 Western Region (Wadi Yalamlam basin)
People in Saudi Arabia consider Makkah Province as one in the western part of the nation. Indeed, the area’s water catchment remains as the biggest in the KSA’s western coastal region. Indeed, the zone spreads to the Red Sea coastline in the western side from the Arabian Shield located in the eastern region. The climatic condition of the zone under study is characterized by the arid features and has a desert-like environment, which remains hot and dry throughout the year. Equally, average temperatures range from 30°C-34°C in summertime and from 20°C-24°C during wintertime (El-Hames et al., 2011). Precipitation remains unbalanced but increases towards the mountains as it comes from the coastal plains. Yearly average precipitation varies from 50 and 100 mm. 30% and 75% represent the average humidity ranges recorded. Equally, evaporation rates range from 200-500 mm per month. Wadi Rabigh’s upper part of the catchment area is located Harrat Rahat plateau, which is associated with lava movements and Precambrian protrusions situated along the Hijaz escarpment (El-Hames et al., 2011). Indeed, the region’s altitude begins at a few meters from the coastline and rises up to 1,200 meters at few inaccessible peaks towards the eastern side. One can find the groundwater level close to the surface towards the mountain’s edge encompassing the progression of the stream.
Mohammadi-Behzad et al. (2018) utilized GIS, statistical extrapolation, and conditional overlaying methods, as well as observed two groundwater potential aquifers in two areas. The first one is situated in the lower region of Haqaq’s spring towards the intersection with Al Nuwabi’s branch. In this area, the breadth of the water-logged area ranges from 10-16 m and the other one is positioned in Al Nuwabi Wadi, an area where the breadth of the saturated region ranges between 20 and 35 m. El-Hames et al. (2011) realized that zones with high underground water potential have catchments that contain alluvial deposits, which form the Wadi Hishash in the nmiddle-upper boundary and Wadi Madrakah at the higher boundary. The regions reflect the agreements associated with ground clarifications. The wells that had the finest groundwater accessibility were privately dug and located on homesteads concentrated in these expanses. The researcher also identified some alluvial areas in this region, which can produce an elevated pumping level because of the deep underground water source (Mohammadi-Behzad et al., 2018). The situation creates another issue associated with the high groundwater possibility in this zone.
Researchers performed a good job in outlining and mapping the underground water probable areas at the Wadi Yalamlam (Sa’diyah sub-basin) using a unified approach with RS and GIS methods. The researcher used six thematic hydrogeological constraints and incorporated within the GIS environment (El-Hames et al., 2011. Based on this study, the lower areas of the Wadi Yalamlam basin provide encouraging indicators for underground water potentiality since they comprise high and restrained probable regions. Figure 11 indicates the 3D viewpoint associated with false color compound and Landsat image wrapped in ASTER GDEM digital advancement model. Indeed, the figure explains underground water disparities in relation to the Wadi Yalamlam basin. The central and upper regions of the Wadi Yalamlam catchment symbolize low groundwater potential areas. In this region, two dyking zones crosscut the various rock units visible in lower areas of the Wadi Yalamlam catchment (Mohammadi-Behzad et al., 2018). Regarding the first dyking zone, one can observe it from the west side of Sheikh Said’s farm. Basic dykes represent zone, which strike approximately in the North-South direction. Equally, regarding the other dyking, one can view it from the southern side of Abu Helal’s farm. The region possesses the NW-SE bearings, as well as and gabbroic structure. The presence of the dykes impacted the underground water restoration in this zone by creating a subsurface water catchment area. The other dyking region creates a boundary between the moderate and high underground water probable zones (Selvam et al., 2016). The latter areas are situated on the northern side of main dyking zone and loose Wadi deposits cover them. Indeed, moderate slope, the deposits, flat zones, low drainage compactness, and shallow underground water areas form advantageous situations for high underground water probability, as well as high permeation levels that boost groundwater pools in the western region of Saudi Arabia. Towards the south of the central dyking area lie the moderate underground water feasible zones (El-Hames et al., 2011. The preparation of the underground water potential regions map involved the utilization of the calculated satellite-based data and incorporated with the use WOP and index overlay GIS prototypes.
5.4 Southern Region (Jazan region)
Jazan region is found in the southern part of Saudi Arabia. Jazan represents the smallest area within Saudi Arabia as compared to the others. It consists of a desert climate accompanied by yearly temperatures of about 30°C. Equally, the region’s climate conditions vary from exceptionally hot in summertime to a bit hot in short winter periods. Precipitation varies from 70-270 mm annually. Since the region’s economy is agricultural-based, the importance of availability of water and its control is imperative. In order to develop acceptable irrigation amenities, the stakeholders involved need to focus on underground water, which remains as the only practical source of water in this arid region. However, Mahmoud and Alazba (2014) model builder tool associated with an ArcGIS model utilizing the ArcGIS to pinpoint the potential precincts for groundwater recharge in this area. The spatial extents of the appropriate probable groundwater recharge regions were recognized with the use of MCE based on AHP scrutiny and considering the five layers (Selvam et al., 2016). Various spatial investigation gadgets were utilized in the prototype to resolve 3-D challenges in the course of pinpointing appropriate areas. Equally, the spatial dissemination of the appropriateness map indicates the excellent and good zones for potential groundwater recharge areas situated within north and west of the Jazan region, while the middle area is considered as excellent and good due to some of its moderate locations (Mahmoud & Alazba, 2014). On the same note, the southern and eastern areas have similar classifications that indicate moderate and inappropriate areas but with appropriate zones. Indeed, 50.5 percent and 31 percent of the study area is categorized as possessing exceptional and the right appropriateness for potential groundwater recharge areas correspondingly, while 16% is ascetically fit and 2.5 % reflects deprived and inappropriate (Mahmoud & Alazba, 2014). The RS and GIS-based charting of potential underground water rejuvenation areas is economical and saves time.
6. Conclusions
Saudi Arabia’s natural environment is arid due to the limited precipitation, hence limited surface water. In this regard, underground water is regarded as the main water resource in the nation. Based on this review, an incorporated tactic of RS and GIS for evaluating the underground water potential areas in Saudi Arabia was assessed. Indeed, the study is significant since it supports the sustainable use groundwater resources and enhances proper management of underground water sources (Selvam et al., 2016). However, the studies revealed that in the northern region, the Wadi beds remain as the most appropriate for groundwater zone while the sand dunes had the least potential for groundwater. On the same note, in the central zone, groundwater potential areas were located in the Wadi networks within Al-Riyadh Province. Furthermore, from the evaluation concerning the western region, the promising areas with groundwater potential in the aquifer involved two places. The first one is situated in the lower part of Haqaq’s spring towards the intersection with Al Nuwabi. The other one is situated at Al Nuwabi Wadi. The high groundwater potential zones of western Saudi Arabia are situated mainly in the sedimentary area of the catchment, Wadi Hishash in the middle–upper boundary and Wadi Madrakah towards the upper boundary. In this area, some alluvial zones were found, which could produce a high pumping level because of the deep underground water point. The feature indicates the high groundwater potentiality in this region. In the southern zone, the excellent and good zones for potential groundwater precincts are situated in the northern and western sides of the Jazan region (Mahmoud & Alazba, 2014). The utilization of RS and GIS methods assist in the process of underground water exploration and detect groundwater potential areas. Administrative agencies and policy makers can use groundwater potential zone maps as an introductory reference in choosing appropriate locations for underground water resources management. As such, the chart will provide data to resident governments and developers regarding the appropriate region for potential extraction of underground water and to safeguard the areas from pollution. Furthermore, incorporated RS and GIS-based approaches act as powerful tools for assessing groundwater potential areas (Mahmoud & Alazba, 2014). Indeed, individuals can use the techniques to identify suitable locations for groundwater withdrawals. The review will play a crucial role in water resource administration in Saudi Arabia since it will assist stakeholders to make informed decisions.
References
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