Ali Al-Maktoumi

Sultan Qaboos University | SQU · Department of Soils, Water and Agricultural Engineering

In this research, we demonstrate the effectiveness of a convolutional neural network (CNN) model, integrated with the ERA5-Land dataset, for accurately simulating daily streamflow in a mountainous watershed. Our methodology harnesses image-based inputs, incorporating spatial distribution maps of key environmental variables, including temperature, s...

Accurate estimation of effective saturated hydraulic conductivity (Ksat) of a vadose zone with an underlying shallow perched aquifer is challenging. Standard pumping tests and double‐ring infiltrometers are unsuitable for this purpose. Therefore, a bailout test (BOT) was conducted in nine soil pits to evaluate the hydraulic properties of the vadose...

This study presents the ‘Dual Path CNN-MLP’, a novel hybrid deep neural network (DNN) architecture that merges the strengths of convolutional neural networks (CNNs) and multilayer perceptrons (MLPs) for regional groundwater flow simulations. This model stands out from previous DNN approaches by managing mixed input types, including both imagery and...

This study aims, as a first attempt, at establishing a framework for multi-objective optimization diagnostic model calibration and uncertainty analysis based on information theory, including mutual information (MI) and variation of information (VI). Moreover, a global sensitivity analysis was performed using the information coefficient of correlati...

Hydrogen is one of the most preferred types of clean energy forms needed to achieve a green economy, considering its potential to be stored in different energy forms. This study aims to review the potential renewable and non-renewable resources that can support the hydrogen economy in Oman. We have critically reviewed the current ongoing green hydr...

The poor performance of traditional surface irrigation systems has motivated a transition to more advanced and efficient irrigation systems, especially in arid areas. However, such a transition often results in some local conflicts between the decision-makers and farmers in fear of losing their original water rights. This study proposes an agent-ba...

Accurate and reliable estimation of Reference Evapotranspiration (ETo) is crucial for water resources management , hydrological processes, and agricultural production. The FAO-56 Penman-Monteith (FAO-56PM) approach is recommended as the standard model for ETo estimation; nevertheless, the absence of comprehensive meteorological variables at many gl...

Partial stored CO2 in a suitable geological reservoir could be used as the heat-bearing media to harvest geothermal energy, as a CO2 utilization method integrated with sequestration. Impacts of geological heterogeneity on CO2 sequestration or water-based geothermal production have been widely recognized and extensively studied. However, very limite...

Groundwater salinization in coastal aquifers is a major socioeconomic challenge in Oman and many other regions worldwide due to several anthropogenic activities and natural drivers. Therefore, assessing the salinization of groundwater resources is crucial to ensure the protection of water resources and sustainable management. The aim of this study...

In this paper, we described a computationally efficient simulation–optimization (S/O) framework for coastal groundwater management (CGM), based on the combined application of numerical modeling, artificial neural networks, and genetic algorithm. The objective was to analyze the ‘trade-off’ between optimality and risk in deriving CGM strategies and...

To mitigate the unfavorable effects of excessive water resources consumption, mainly induced by poor performance of irrigation practices, efficient water resource management strategies are required. In response to this need, we have, in an innovative way, enhanced the water resources management (WRM) strategies by both considering the regional cond...

Renewable energy is becoming more attractive to meet energy demands due to increasing concerns about carbon dioxide (CO2) emission, environmental pollution, and exhaustion of oil/gas reserves. In addition to oil and solar energy sources, Oman also has abundant low-enthalpy geothermal energy resources in the northern mountain region to be explored a...

Geothermal harvest by using sequestered CO2 in underground reservoirs as the working fluid is an effective approach to reduce CO2 emission and fossil energy consumption. The integrated impact of reservoir boundary conditions, well placement and operations on this CO2 geothermal production (CGP) is unclear. This study aims to analyse these influence...

Innovative pedagogical approaches that integrate classroom learning from diverse soil science courses with practical skills and field-based competencies are needed. This paper suggests merging our own “Soil Skills” (SSK) pedagogical method with the “Soil Judging Contest” (SJC), a teaching approach supported by the American Society of Agronomy and t...

This paper presents a novel approach to analyzing uncertainty in complex groundwater models based on the Approximate Bayesian Computation (ABC) framework and information-theoretic summary statistics. Two summary statistics using the concepts of mutual information and variation of information are formulated as distance function measures of the ABC....

Depleted oil/gas reservoirs are excellent candidates to apply CO2 Plume Geothermal (CPG) production, a promising CO2 storage and utilization technique. However, most oil/gas reservoirs are separated into geological blocks by faults, and the impact of boundary conditions and formation heterogeneity on CPG performance is still challenging. This study...

Depleted oil/gas reservoirs can be used for CO2 sequestration and utilization; CO2 plume geothermal (CPG) production from a CO2 geological storage reservoir has emerged as a viable approach owing to its favorable thermodynamic properties. However, most oil/gas reservoirs are separated by faults into geological blocks, and the impact of these fault...

This paper reports on the development of a model intended to provide an early warning indication of pollution caused by oil produced water and also serve as a predictive tool for compliance/noncompliance to the set guidelines related to the discharge of wastewater into municipals' channels. The development of this model made use of the results obta...

Although CO 2 behaviors in porous subsurface formations have been extensively investigated during decades of CO 2-enhanced oil recovery and CO 2 sequestration practices, very limited efforts have been focused on the associated CO 2-circulated geo-thermal power plant on the surface. This study aims to contribute to this field by numerically evaluati...

Irrigation schemes depending on Aflaj, Qanats, Khariz, and Foggaras are found all over the world. In Oman, more than 3000 ancient Aflaj are still operated and managed the way they used to be a hundred years ago. Only a handful are currently automated for demonstration purposes. However, there has been no adoption of these automated systems by far...

Large-scale characterization of water table depth in shallow aquifers in hyper-arid areas provides crucial insights into groundwater dynamics under increasing anthropogenic discharge and climatic fluctuations. Due to their penetration capabilities into arid soils, airborne VHF sounding radars can achieve this objective under specific system design,...

Soil erosion, sediment yield, and sediment transport associated with flash flooding in arid regions result in reservoir storage losses, decreased infiltration, high evaporation rates, and degradation of downstream channels. However, the lack of observational data from wadi systems and an empirical formula to compute sediment yield has hindered rese...

CO2 plume geothermal (CPG) production is an emerging CO2 utilization approach coupled with CO2 geological sequestration. Geological heterogeneity plays an important role in CO2 fluid and heat flow in the formation. Although the impact of heterogeneity has been investigated during CO2 injection for many sequestration projects, few studies have been...

It is often necessary for water managers to make major decisions when managing water resources at the scale of watershed. Nonetheless, decision-makers cannot directly use the simulation models results due to lack of modeling knowledge and computer skills. Water decision-makers are more focused on user-friendly features that emphasize the integratio...

The use of CO2 as the heat transmission fluid, increases the efficiency of geothermal energy extraction from low-enthalpy resources such as depletion oil and gas reservoirs. In the resulting so-called CO2 plume geothermal (CPG) systems, the optimal choice of well position and operational parameters represents a strategic decision problem, due to it...

Integrated CO2 (carbon dioxide) geologic storage (CGS) and CO2 plume geothermal (CPG) production provides an attractive approach not only to reduce atmospheric CO2 concentration but also to generate carbon-free geothermal energy to supplement electricity power. The current CGS-CPG studies are mostly limited to large-scale thick saline formations wi...

CO2 circulated geothermal production can be integrated with CO2 geological sequestration as a utilization method to offset cost. In the past 10 years, many studies have demonstrated it is a more efficient geothermal harvest approach than the traditional water based method, owing to CO2’s specific thermophysical properties. Although impact of geolog...

Recharge dams represent one of few engineering techniques to harvest flashfloods water in arid zones for augmenting the limited water resources. Formation of a low-permeable cake by deposition of suspended particles transported by ephemeral floods is a common problem for dams in arid regions (e.g. Oman, Saudi Arabia, Iran, and Tunisia). Accumulatio...

Proper water allocation plays a key role in sustainable water resources management due to limited water resources and increasing demand for agricultural water consumption. Although the soil water balance approach is widely used to determine agricultural water allocation, simultaneous application of this approach and optimization of agricultural wat...

In the Sultanate of Oman, 174 dams have been constructed as of 2021 for different purposes: flood protection (3 dams), recharge (56) and surface storage (115) with a total storage capacity exceeding 300 million m3. Recharge dams represent one of few engineering techniques to harvest flashfloods water in wadi systems in arid zones for the purpose of...

Managed Aquifer Discharge (MAD) through trenches lowers the water table of ‘shallow perched aquifers’ in urban areas (Muscat-Oman). Drawdown of the water table in periodic trenches or a single trench is experimentally studied in a sandbox, and modelled numerically (by HYDRUS2D) and analytically. Evaluation of transient flow fields of pore pressure...

Recently, Wadi flash floods (WFFs) have happened frequently in arid environments, resulting in great damage the society and the environment. In Oman, severe WFFs have occurred repeatedly within the last 10 years causing a huge impact on human lives and properties. This paper aims at introducing the framework of an international collaboration projec...

Groundwater in the border regions of Sultanate of Oman and the United Arab Emirates (UAE), near Al-Buraimi and Al-Ain areas, has significant socioeconomic importance, both as a source of drinking water and as a factor of production in agriculture. In recent decades, substantial development of irrigated agriculture and city expansion has occurred, w...

A shallow water table (SWT) rises up to several centimeters below the soil surface and even exfiltrates making surface impoundments that are common in humid climates. Recently, SWTs emerged even in arid and semi-arid regions of several metropolitan areas of the Arabian Gulf Cooperation Council (GCC) countries with a pernicious impact on the urban i...

CO2 plume geothermal (CPG) production built on the ongoing or completed Carbon Dioxide (CO2) geological storage (CGS) offers an emerging technique to harvest non-carbon renewable energy and offset CGS cost. Several studies on integrated CGS and CPG considered traditional 5-spot well placement in large-scale and thick saline formations with open bou...

Models provide invaluable visions to decision-makers for basin-scale management of water resources. However, decision-makers have difficulties in directly using these complex models. Water managers are primarily interested in user-friendly features allowing an integration of their judgments into the decision-making process, rather than applying det...

Rises of the water table up to several centimeters below the ground surface and even exfiltration of groundwater into surface depressions are common in humid climates. Recently, a shallow water table (SWT) has emerged in several cities of the arid to semi-arid region of the Arabian Gulf Cooperation Council (GCC) countries that threatens the urban i...

Combined simulation–optimization (CSO) schemes are common in the literature to solve different groundwater management problems, and CSO is particularly well-established in the coastal aquifer management literature. However, with a few exceptions, nearly all previous studies have employed the CSO approach to derive static groundwater management plan...

Subsurface dams, strongly advocated in the 1992 United Nations Agenda-21, have been widely studied to increase groundwater storage capacity. However, an optimal allocation of augmented water with the construction of the subsurface dams to compensate for the water shortage during dry periods has not so far been investigated. This study, therefore, p...

Waterlogging of urban area soil in a hyperarid climate, caused by impedance of evapotranspiration due to land cover by an impervious pavement, is studied by a multidisciplinary team of researchers (hydropedeologists, hydrogeologists, groundwater engineers, soil physicists and mathematical modelers). In this paper, a study unique for an arid/hyperar...

This book presents the most recent innovative studies in the field of water resources for arid areas to move towards more sustainable management of the resources. It gathers outstanding contributions presented at the 2nd International Water Conference on Water Resources in Arid Areas (IWC), which was held online (Muscat, Oman) in November 2020. Pap...

Seawater intrusion (SWI) has been widely investigated in physical sandbox-field experiments and analytical-numerical mathematical models. However, to the best of our knowledge, there were no studies of a commingled dynamics of the triad of saline water, natural fresh groundwater and freshwater injected in managed aquifer recharge (MAR) using sand t...

Seawater intrusion (SWI) has been widely investigated in physical sandbox-field experiments and analytical-numerical mathematical models. However, to the best of our knowledge, there were no studies of a commingled dynamics of the triad of saline water, natural fresh groundwater and freshwater injected in managed aquifer recharge (MAR) using sand t...

Evaporation ponds (EVPs) are among the most cost-effective, and simple wastewater treatment technologies used in many regions/countries with high solar radiation levels. However, its operational limitations, which include the overflow of wastewater, leakages via liners, and large surface area of the EVP that is exposed to atmosphere, creates a nega...

Surface water impoundment in an unlined triangular ditch during a single managed aquifer recharge (MAR) infiltration pulse lasts for time Te, after which all initially disposed water seeps into a homogenous isotropic coarse soil. In ditches with initial water W0 with depth H0 and length L, the dyad (W0,H0) vanishes at t→Te. The ditch slope that min...

Many wells become abandoned with the depletion of oil and gas reservoirs, and low-enthalpy geothermal energy could be extracted from these abandoned wells. CO2 has been proposed and studied as the working fluid for mining such geothermal energy sources, owing to its favorable thermodynamic properties. The objective of this study is to develop an un...

In the past decade, techno-economic feasibility of using CO2 as a working fluid to harvest geothermal energy has been studied and demonstrated in both hot-dry rock and deep brine aquifers. Potential geothermal resources have been suggested by hydrogeological surveys in North Oman area. Many depleting petroleum reservoirs in this area provide excell...

The primary objective of this study was to quantify the impacts of climate change on groundwater recharge using the 3D numerical-based HydroGeoSphere (HGS) model in the Ubar/ Shisr Agricultural region in South of Oman. This region has multi-million US dollar irrigated agriculture project purposely developed for the food security of the country. Exc...

Abstract: The primary objective of this study was to quantify the impacts of climate change on groundwater recharge using the 3D numerical-based HydroGeoSphere (HGS) model in the Ubar/ Shisr Agricultural region of Oman. This region has multi-million US dollar irrigated agriculture purposely developed for the food security of the country. Excessive...

Water scarcity in the Arabian Gulf countries along with increasing challenges for water supply due to increasing developments in different sectors and population growth necessitate implementation of all feasible measures to augment and manage water resources in a sustainable way. Among already implemented measures is building of recharge dams which...

In this study, we present an interactive problem-based learning environment, namely, the “Soil Skills” contest for final year students majoring in Soil Sciences, a BSc program at Sultan Qaboos University, Oman. This five-day component of a compulsory field-course exemplifies an active learning approach, which has been promoted by higher educators b...

Seepage through an aquifer, the hydraulic conductivity of which varies vertically, is studied by using the Dupuit-Forchheimer approximation (Girinskii’s potential) and numerically by FDM-MODFLOW and FEM-HYDRUS-2D. In urban water hydrology, the effect of compaction of the top stratum of an aquifer on the flow rate and the position of the water table...

Geothermal energy production and consumption is one of the world’s top priorities as it ensures sustainable developments via steady yield of renewable energy and helps to reduce atmospheric carbon dioxide (CO2) emissions and air pollution levels. The objective of this study is to critically assess geothermal energy prospects in terms of number of p...

An increase in groundwater storage in aquifers in arid areas improves water security. Most desalination water production around the globe involves the private sector in the form of “build, operate, and transfer” or “build, operate, and own” agreements. Take-or-pay contracts are the most dominant contracts in the desalination industry. The water uti...

In arid lands, the coarse porous materials of the beds of ephemeral streams (locally called Wadis in Oman) are conduits for the freshwater that infiltrates-exfiltrates through these beds during irregular rainfall events. The percolating water through the wadi bed forms perched or localized aquifers that severs as a source of water supply for the sc...

In this paper, we describe a computationally efficient simulation-optimization (S/O) framework for coastal groundwater management (CGM), based on the combined application of numerical modeling, artificial neural networks and genetic algorithm. The objective is to analyze the ‘trade-off’ between optimality and risk in deriving CGM strategies, and to...

Understanding the eco-hydrology of natural sand dunes (Maliva and Missimer, 2012) can be used in design of mini-dunes (crest ≤ 1 m) as agroengineerd “self-irrigation units”. Minidunes can intercept moisture from humid air and a shallow water table (e.g. in sabkha landforms). Thus, a spot of wet low-salinity fine-textured soil can be maintained natu...

Evaporation ponds are a known cost-effective option which are also environmentally-friendly enough to be considered a viable solution for disposal of oil-produced water (OPW), especially in areas with high evaporation rates. However, there is no study to particularly relate OPW physico-chemical properties and climatic variables to optimum dimension...

Intertidal sediments host many biogeochemical processes which drastically affect coastal ecosystems. Dissolved Oxygen (DO) plays a major role in many of these biogeochemical reactions, and is of primary importance for intertidal groundwater quality. Groundwater level of intertidal zone fluctuates regularly corresponding to the tidal cycle. During t...

Siltation of reservoir beds of recharge dams in arid climates seriously diminishes dams' storage capacity, lessens infiltration and deep percolation rates, increases water loss via evaporation, and ultimately lowers the recharge efficiency to the underlying unconfined aquifer. This study explores possibilities for enhancing the infiltration rate of...

New water-conserving irrigation technologies are vital in arid countries. We investigated the effects of (i) soil substrates made of Smart Capillary Barrier Wick (SCB-W), consisting of silt loam blocks surrounded by sand-sheathes and irrigated with a sand wick cylinder (WC) as compared to a control (homogenous soil irrigated by the same wick system...

An isosceles triangle in a vertical cross-section of a trench is considered as a boundary from which free water in the trench seeps into a porous bed. A finite, initially impounded water volume vanishes from the channel and soil moisture moves in conjugation with surface water in a transient 2-D saturated-unsaturated regime. If capillarity is ignor...

Simulation-optimization framework is a widely used approach for numerical model calibrations, though its primary difficulty is its high-demand of computational efforts. In this study, Bagging MARS (BMARS) adapted from Multivariate Adaptive Regression Splines (MARS) algorithm, is used to construct the surrogate of a three-dimensional CO2 reservoir m...

An isosceles triangle in a vertical cross-section of a trench is considered as a boundary from which free water in the trench seeps into a porous bed. A finite, initially impounded water volume vanishes from the channel and soil moisture moves in conjugation with surface water in a transient 2-D saturated-unsaturated regime. If capillarity is ignor...

The hydrological and economic feasibility of aquifer storage and recovery (ASR) of excess desalinated water and managed aquifer recharge (MAR) using tertiary treated wastewater (TTWW) to manage stressed coastal aquifers in Oman has been studied numerically using the code, MODFLOW 2005 and the different transport packages MT3DMS, and MODPATH. The cu...

لقد أقرت سلطنة عمان أهداف التنمية المستدامة 2030 مع دول العالم في قمة الأمم المتحدة في سبتمبر 2015م وتعمل بخطى سريعة لتحقيق هذه الأهداف؛ فقد أُدمجت أهداف التنمية المستدامة 2030 ضمن المرتكزات الرئيسية للخطة الخمسية التاسعة للسلطنة وعملت على موائمتها مع استراتيجية السلطنة 2040م. إن أهداف التنمية المستدامة، هي دعوة عالمية للقضاء على التحديات التي توا...

Storage of water in aquifers using injection wells is an efficient way for utilizing excess desalinated water in arid regions. In this investigation we estimate the benefits of optimally recharging seasonal surplus desalinated water into a strategic coastal aquifer already benefitting from natural recharge of flash‐floods water by a recharge dam. S...