Floods accompanied by thunderstorms in developed cities are hazardous, causing damage to infrastr... more Floods accompanied by thunderstorms in developed cities are hazardous, causing damage to infrastructure. To secure infrastructure, it is important to employ an integrated approach, combining remote sensing, GIS and precipitation data. The model was developed based on the estimation of event-based runoff and investigated the relationship between runoff and impervious surfaces. The novel approach of combining Hydrologic Engineering Center's River Analysis System (HEC-GeoRAS) along with satellite imagery was utilized, where spatial data was combined with real-time values to run the model. As a first step, the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model was fed with information about precipitation, slope, soil type, as well as land use and land cover. The results reveal that the subbasins of Deira, Nief and Jumeirah have the largest impervious area and, thus, a higher probability of flood occurrence. The model was calibrated and validated using previous runoff events and by comparing observed and simulated streak flow and peak discharge against those reported in previous studies. It was found that the model is efficient and can be used in similar regions.
The Emirate of Abu Dhabi has relied on groundwater as a source of fresh water for several decades... more The Emirate of Abu Dhabi has relied on groundwater as a source of fresh water for several decades, which has resulted in the deterioration of non-renewable groundwater aquifers. This has led to the installation of desalination plants for fresh water supply. This research aims to increase strategic water reserves in the eastern district of Abu Dhabi by analyzing the best locations for aquifer storage and recovery (ASR). The ASR technology offers an opportunity to store large volumes of water for later beneficial use. This study explores an option of using excess desalination water for ASR recharge in the eastern district Al Ain region of Abu Dhabi. A limiting factor in the application of the ASR technology is the lack of suitable sites. Detailed hydrogeological and operational knowledge of the studied areas helped in identifying potential sites for ASR based on a scoring system. Determining best locations for managed aquifer recharge is a crucial design step. Five scenarios were studied at Al-Khrair and Al-Shuwaib sites in Al Ain region. Results show that a wider distribution of injection wells with intervals more than 1200 m is more suitable to overcome the excessive head buildup. Based on the adopted criteria, Al-Khrair was the best site for recharge followed by Al-Shuwaib. Al-Khrair site can be recharged at 64,000 m 3 d −1 for seven years, while Al-Shuwaib site can be recharged at 64,000 m 3 d −1 for only two years. The supply of freshwater is a global challenge that gives rise to issues related to water security 1-4. The rapid development and continuous growth of the population in the United Arab Emirates (UAE) has resulted in an increase in water demand 5,6. According to the Statistical Yearbook of Abu Dhabi (SCAD) 7 , the population of the Al Ain region was 738,500 in mid-2015, with an increase of around 26% compared to the population in mid-2010. According to Younis 8 , the population of the Al Ain region is expected to be doubled in 2030 to reach 1,373,265. Abu Dhabi City has a per capita water consumption of 590 L d −1 according to the Environment Agency, Abu Dhabi 9. Challenges to maintain a sustainable water supply include the absence of surface water, due to scarcity of rainfall, and high evaporation levels; thus, groundwater is the only conventional water resource 10. In addition to population growth, other factors such as the expansion of irrigated agricultural lands also require groundwater. The consumption of groundwater by agricultural activities, households, and other uses are 90, 2, and 8%, respectively. The annual groundwater recharge and abstraction in the UAE were estimated to be 120 and 880 Mm 3 yr −1 , respectively 11. A large portion of the water demand is provided by desalinated water produced by coastal desalination plants such as the Taweela desalination plant, which employs multi-stage flash (MSF) and multi-effect distillation (MED) technology, in the Emirate of Abu Dhabi and the Jabal Ali desalination plant, which operates on the MSF technology, in the Emirate of Dubai 12. In the Emirate of Abu Dhabi, 71.3% of the desalinated water is consumed by agriculture, forestry, and landscaping, which is estimated to be more than 2,000 Mm 3 yr −1 , 16.5% by the domestic sector, 4.7% by the governmental sector, 6.5% by the commercial sector, 0.8% by the industrial sector, and 0.1% by other sectors 9 water demand 13. The need for an alternative approach to manage water demand and provide uninterrupted freshwater supply is a major concern in the Emirate of Abu Dhabi 14. Managed aquifer recharge is considered a cost-effective technique compared to aboveground alternatives that require the construction of water treatment plants, surface reservoirs, and large tracts of land. In addition, there may be insufficient space for aboveground water storage tanks, especially in urban areas 13,15. Therefore, the Emirate of Abu Dhabi needs a large storage system that will overcome
Floods are among the devastating types of disasters in terms of human life, social and financial ... more Floods are among the devastating types of disasters in terms of human life, social and financial losses. Authoritative data from flood gauges are scarce in arid regions because of the specific type of dry climate that dysfunctions these measuring devices. Hence, social media data could be a useful tool in this case, where a wealth of information is available online. This study investigates the reliability of flood related data quality collected from social media, particularly for an arid region where the usage of flow gauges is limited. The data (text, images and videos) of social media, related to a flood event, was analyzed using the Machine Learning approach. For this reason, digital data (758 images and 1413 video frames) was converted into numeric values through ResNet50 model using the VGG-16 architecture. Numeric data of images, videos and text was further classified using different Machine Learning algorithms. Receiver operating characteristics (ROC) curve and area under curve (AUC) methods were used to evaluate and compare the performance of the developed machine learning algorithms. This novel approach of studying the quality of social media data could be a reliable alternative in the absence of real-time flow gauges data. A flash flood that occurred in the United Arab Emirates (UAE) from March 7-11, 2016 was selected as the focus of this study. Random forest showed the highest accuracy of 80.18% among the five other classifiers for images and videos. Precipitation/rainfall data were used to validate social media data, which showed a significant relationship between rainfall and the number of posts. The validity of the machine learning models was assessed using the area under the curve, precision-recall curve, root mean square error, and kappa statistics to confirm the validity and accuracy of the model. The data quality of YouTube videos was found to have the highest accuracy followed by Facebook, Flickr, Twitter, and Instagram. These results showed that social media data could be used when gauge data is unavailable.
Identification of selection criteria is a crucial initial step in aquifer storage and recovery (A... more Identification of selection criteria is a crucial initial step in aquifer storage and recovery (ASR) projects. The lack of knowledge of suitable sites hydrological and geological characteristics could be limiting factors in the application of ASR technology. A total of 20 sites were evaluated in the eastern district of Abu Dhabi emirate, using available data at each site, based on 15 different criteria. The study area is an agricultural intense region, where groundwater is extensively used for irrigation. The developed framework is proven to be useful in terms of ASR planning. The framework is based on weighting factors assigned to each hydrogeological and additional characteristic based on its relative importance in the ASR site selection. The developed scoring scheme is used with the 20 sites to assess the possibility of finding a suitable site for potential ASR with promising aquifer performance. The total score was used to develop final ASR suitability maps. The highest score of 142 out of 160 (89% ASR suitability) was achieved in Al Khrair site followed by Al Dhahir with 138 out of 160 (86%), Al Shuwaib with 136 out of 160 (85%) and Al Bateen with 126 out of 160 (79%). The sites located at the eastern part of the study area had the highes scores. The score is decreased at the sites located at the western and southern parts of the study area, with the lowest score of 107 out of 160 at Abu Huraibah. The characterization of sites should be mainly based on the availability of pumping stations in the vicinity of the study area, that will be helpful in the future implementation of the ASR project. The detailed hydrogeological and operational data of the studied sites helped in the ASR assessment.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain
Land use land cover change Remote sensing Groundwater mapping Urbanisation causes land degradatio... more Land use land cover change Remote sensing Groundwater mapping Urbanisation causes land degradation problems, including an increased pressure on natural resources and management of water resources. This study aims to investigate the impact of the spatio-temporal dynamics of land use land cover (LULC) changes on groundwater table in the region of Al Ain, United Arab Emirates (UAE), from 2006 to 2016. The Landsat images, Landsat ETM for 2006 and Landsat 8 for 2016, were acquired from the earth explorer site. A semi-supervised hybrid classification method was used for image classification and postclassification techniques for LULC change detection. The study area was categorised into six major LULC classes. These are agriculture/farms/oasis, gardens/playgrounds, urban areas, sandy areas, lake and mixed urban/ sandy areas. Accuracy assessment of LULC were evaluated using confusion matrix and ground truthing. The obtained land use and land cover maps were also correlated with spatial groundwater table maps prepared with groundwater data. It was found that agriculture/farms/oasis and urban areas expanded from 42,560 ha to 45,950 ha (7.38%) and from 8150 ha to 9105 ha (10.49%) from 2006 to 2016, respectively. The corresponding water demand was increased by 9.56% and 22.22%, respectively. Natural sandy area was found to decrease by 8.10%. As groundwater is major source of water for agriculture in this region, the spatial maps also revealead average declining rate of groundwater depth 40.44% with expansion of urban and agricultural areas over the last 10 years. The outcomes of the study would help concerning authorities for a sustainable management of its land and groundwater resources.
Groundwater is more prone to contamination due to its extensive usage. Different methods are appl... more Groundwater is more prone to contamination due to its extensive usage. Different methods are applied to study vulnerability of groundwater including widely used DRASTIC method, SI and GOD. This study proposes a novel method of mapping groundwater vulnerability using machine learning algorithms. In this study, point extraction method was used to extract point values from a grid of 646 points of seven raster layer in the Al Khatim study area of United Arab Emirates. These extracted values were classified based on nitrate concentration threshold of 50 mg/L into two classes. Machine learning models were developed, using depth to water (D), recharge (R), aquifer media (A), soil media (S), topography (T), vadose zone (I) and hydraulic conductivity (C), on the basis of nitrate class. Classified 'groundwater vulnerability class values' were trained using 10-fold cross-validation, using four machine learning models which were Random Forest, Support Vector Machine, Naïve Bayes and C4. 5. Accuracy showed the model developed by Random Forest gained highest accuracy of 93%. Four groundwater vulnerability maps were developed from machine learning classifiers and was compared with base method of DRASTIC index. The efficiency, accuracy and validity of machine learning based models were evaluated based on Receiver Operating Characteristics (ROC) curve and Precision-Recall curve (PRC). The results proved that machine learning is an efficient tool to access, analyze and map groundwater vulnerability.
The Gulf Cooperation Council (GCC) countries, which consist of Bahrain, Kuwait, Oman, Qatar, Saud... more The Gulf Cooperation Council (GCC) countries, which consist of Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates, possess abundant oil resources but scarce water resources. Low rainfall and high evaporation rates threaten sustainable development in this region. Currently, water demands for domestic and industrial sectors in these countries are mostly met by non-conventional resources such as desalinated water and treated wastewater. In order to augment the freshwater resources, better water management planning, with suitable assessment tools, is necessary. The use of stable and radioactive environmental isotopes has proven to be a powerful assessment tool in many hydrological problems. Combination of previous isotopic and hydrological studies of the Arabian Peninsula could provide an insight on the dynamics of natural processes affecting this water-scarce region. This paper groups many of these studies into various categories based on their objectives, including identification of recharge areas, assessment of groundwater dynamics, and estimation of groundwater age and residence time. Results of previous isotope studies in the GCC countries are put together to identify the sources of precipitation and estimate rates of evaporation, which is the major cause of water loss in these countries. Mediterranean Sea is the major source of vapor for all GCC countries. Local moisture in the UAE is derived from the Arabian Sea and the Indian Ocean, whereas in Saudi Arabia it either originates from the Atlantic Ocean, the Arabian Sea, or the Indian Ocean. Evaporation alters the isotopic composition of groundwater which is mainly controlled by relative humidity that varies between 20% and 90% in the GCC countries. The slope of the evaporation line, compared to Local Meteoric Water Lines (LMWLs), for Bahrain, Kuwait and northern Oman indicates a moderate rate of evaporation due to rapid infiltration of storm water. In contrast, the evaporation line slope for Qatar, southern Oman and Saudi Arabia are higher than the slopes of the LMWLs showing a relatively low rate of evaporation. The UAE groundwater slope is smaller than that of LMWL indicating high evaporation rate of surface water prior to infiltration. The age of groundwater in the GCC countries indicates residence time since late Pleistocene and early Holocene. Hydrochemical data show that groundwater in the GCC countries is contaminated due to evaporation, irrigation return flow and saltwater intrusion.
Groundwater constitutes an important part of the available water resources in arid areas. Knowled... more 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.
Assessing the current levels of greenhouse gas (GHG) emissions from road transportation projects ... more Assessing the current levels of greenhouse gas (GHG) emissions from road transportation projects allows for benchmarking and is essential for potential emissions reduction. The objective of this study was to estimate the GHG emissions associated with the construction and operation of three road cases-two primary roads and one secondary road network-in Abu Dhabi, United Arab Emirates. The GHG emissions produced by the study cases were estimated using the RoadCO 2 estimation tool. Results showed that the total emissions (in kg CO 2 e/m 2 /y) range from 76 for the secondary road case to 1100 for the primary road cases. The operation phase is responsible for 94-98% of these emissions; the construction phase is responsible for the rest. Road works contributed the most to GHG emissions during the construction phase. The contribution of the remaining categories of the construction phase fluctuates within a certain case and among the considered cases. The equipment used in the construction phase for the three cases contributed 15-70% of the total phase emissions, while the remaining emissions were due to construction materials. In the operation phase, emissions were mainly generated by vehicle movement. Street lighting also contributed to emissions during the operation phase. On the other hand, the irrigation of planted trees along the road had a very low impact on GHG emissions, and carbon sequestration by these trees had a negligible effect in terms of acting as a carbon sink. The results obtained from this study were compared with other cases reported in the literature.
The expected increase in the world's population from 2000 to 2020 was about 50% in Africa, 25% in... more The expected increase in the world's population from 2000 to 2020 was about 50% in Africa, 25% in Asia, 14% in the United States, and À2% in Europe (Dore, 2005). This increase is coupled with an increase in water demand. However, industrial and domestic water demand increased twice compared to the rate of population increase. This, of course, is adding pressure on the already limited freshwater resources. On earth, about 3% of the total 1360 million km 3 of water present is fresh water. Out of this, only 1% of water is within human reach and only 0.3% is considered renewable (Dore, 2005). With this limited available freshwater resource and due to variation in its distribution, one out of four persons on earth is suffering from an inadequate supply of fresh water. The United Nations predicted that "about 7 billion people in 48 countries will face water stress or conditions of scarcity by the middle of the century" (Hameeteman, 2013). Scarcity in water resources is amplified given that the available natural water resources are increasingly exposed to pollution. Pollution could be induced in the form of saltwater intrusion due to overexploitation of groundwater reserves, discharge of untreated wastewater into water bodies, lack of proper sewage collection, excessive use of pesticides, leakage of oil pipelines, or degradation of the quality of rainfall due to air pollution or many other forms of induced pollutants in the environment. "The quality of water is as important as its quantity" (Mohamed et al., 2005). The salinity (a measure of the level of total dissolved solids [TDS]) of water available on earth is up to 10,000 mgL À1 , whereas salinity of seawater is in the range of 35,000e45,000 mgL À1 (Eltawil et al., 2009). However, the World Health Organization sets a standard of permissible limits of salinity in drinking water that ranges between 500 and 1000 mgL À1 (WHO, 2004). Given that freshwater resources are almost exhausted in many countries, a study by Clarke (2013) points to the scarcity of water and its degraded quality in several European countries,
Floods accompanied by thunderstorms in developed cities are hazardous, causing damage to infrastr... more Floods accompanied by thunderstorms in developed cities are hazardous, causing damage to infrastructure. To secure infrastructure, it is important to employ an integrated approach, combining remote sensing, GIS and precipitation data. The model was developed based on the estimation of event-based runoff and investigated the relationship between runoff and impervious surfaces. The novel approach of combining Hydrologic Engineering Center's River Analysis System (HEC-GeoRAS) along with satellite imagery was utilized, where spatial data was combined with real-time values to run the model. As a first step, the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model was fed with information about precipitation, slope, soil type, as well as land use and land cover. The results reveal that the subbasins of Deira, Nief and Jumeirah have the largest impervious area and, thus, a higher probability of flood occurrence. The model was calibrated and validated using previous runoff events and by comparing observed and simulated streak flow and peak discharge against those reported in previous studies. It was found that the model is efficient and can be used in similar regions.
The Emirate of Abu Dhabi has relied on groundwater as a source of fresh water for several decades... more The Emirate of Abu Dhabi has relied on groundwater as a source of fresh water for several decades, which has resulted in the deterioration of non-renewable groundwater aquifers. This has led to the installation of desalination plants for fresh water supply. This research aims to increase strategic water reserves in the eastern district of Abu Dhabi by analyzing the best locations for aquifer storage and recovery (ASR). The ASR technology offers an opportunity to store large volumes of water for later beneficial use. This study explores an option of using excess desalination water for ASR recharge in the eastern district Al Ain region of Abu Dhabi. A limiting factor in the application of the ASR technology is the lack of suitable sites. Detailed hydrogeological and operational knowledge of the studied areas helped in identifying potential sites for ASR based on a scoring system. Determining best locations for managed aquifer recharge is a crucial design step. Five scenarios were studied at Al-Khrair and Al-Shuwaib sites in Al Ain region. Results show that a wider distribution of injection wells with intervals more than 1200 m is more suitable to overcome the excessive head buildup. Based on the adopted criteria, Al-Khrair was the best site for recharge followed by Al-Shuwaib. Al-Khrair site can be recharged at 64,000 m 3 d −1 for seven years, while Al-Shuwaib site can be recharged at 64,000 m 3 d −1 for only two years. The supply of freshwater is a global challenge that gives rise to issues related to water security 1-4. The rapid development and continuous growth of the population in the United Arab Emirates (UAE) has resulted in an increase in water demand 5,6. According to the Statistical Yearbook of Abu Dhabi (SCAD) 7 , the population of the Al Ain region was 738,500 in mid-2015, with an increase of around 26% compared to the population in mid-2010. According to Younis 8 , the population of the Al Ain region is expected to be doubled in 2030 to reach 1,373,265. Abu Dhabi City has a per capita water consumption of 590 L d −1 according to the Environment Agency, Abu Dhabi 9. Challenges to maintain a sustainable water supply include the absence of surface water, due to scarcity of rainfall, and high evaporation levels; thus, groundwater is the only conventional water resource 10. In addition to population growth, other factors such as the expansion of irrigated agricultural lands also require groundwater. The consumption of groundwater by agricultural activities, households, and other uses are 90, 2, and 8%, respectively. The annual groundwater recharge and abstraction in the UAE were estimated to be 120 and 880 Mm 3 yr −1 , respectively 11. A large portion of the water demand is provided by desalinated water produced by coastal desalination plants such as the Taweela desalination plant, which employs multi-stage flash (MSF) and multi-effect distillation (MED) technology, in the Emirate of Abu Dhabi and the Jabal Ali desalination plant, which operates on the MSF technology, in the Emirate of Dubai 12. In the Emirate of Abu Dhabi, 71.3% of the desalinated water is consumed by agriculture, forestry, and landscaping, which is estimated to be more than 2,000 Mm 3 yr −1 , 16.5% by the domestic sector, 4.7% by the governmental sector, 6.5% by the commercial sector, 0.8% by the industrial sector, and 0.1% by other sectors 9 water demand 13. The need for an alternative approach to manage water demand and provide uninterrupted freshwater supply is a major concern in the Emirate of Abu Dhabi 14. Managed aquifer recharge is considered a cost-effective technique compared to aboveground alternatives that require the construction of water treatment plants, surface reservoirs, and large tracts of land. In addition, there may be insufficient space for aboveground water storage tanks, especially in urban areas 13,15. Therefore, the Emirate of Abu Dhabi needs a large storage system that will overcome
Floods are among the devastating types of disasters in terms of human life, social and financial ... more Floods are among the devastating types of disasters in terms of human life, social and financial losses. Authoritative data from flood gauges are scarce in arid regions because of the specific type of dry climate that dysfunctions these measuring devices. Hence, social media data could be a useful tool in this case, where a wealth of information is available online. This study investigates the reliability of flood related data quality collected from social media, particularly for an arid region where the usage of flow gauges is limited. The data (text, images and videos) of social media, related to a flood event, was analyzed using the Machine Learning approach. For this reason, digital data (758 images and 1413 video frames) was converted into numeric values through ResNet50 model using the VGG-16 architecture. Numeric data of images, videos and text was further classified using different Machine Learning algorithms. Receiver operating characteristics (ROC) curve and area under curve (AUC) methods were used to evaluate and compare the performance of the developed machine learning algorithms. This novel approach of studying the quality of social media data could be a reliable alternative in the absence of real-time flow gauges data. A flash flood that occurred in the United Arab Emirates (UAE) from March 7-11, 2016 was selected as the focus of this study. Random forest showed the highest accuracy of 80.18% among the five other classifiers for images and videos. Precipitation/rainfall data were used to validate social media data, which showed a significant relationship between rainfall and the number of posts. The validity of the machine learning models was assessed using the area under the curve, precision-recall curve, root mean square error, and kappa statistics to confirm the validity and accuracy of the model. The data quality of YouTube videos was found to have the highest accuracy followed by Facebook, Flickr, Twitter, and Instagram. These results showed that social media data could be used when gauge data is unavailable.
Identification of selection criteria is a crucial initial step in aquifer storage and recovery (A... more Identification of selection criteria is a crucial initial step in aquifer storage and recovery (ASR) projects. The lack of knowledge of suitable sites hydrological and geological characteristics could be limiting factors in the application of ASR technology. A total of 20 sites were evaluated in the eastern district of Abu Dhabi emirate, using available data at each site, based on 15 different criteria. The study area is an agricultural intense region, where groundwater is extensively used for irrigation. The developed framework is proven to be useful in terms of ASR planning. The framework is based on weighting factors assigned to each hydrogeological and additional characteristic based on its relative importance in the ASR site selection. The developed scoring scheme is used with the 20 sites to assess the possibility of finding a suitable site for potential ASR with promising aquifer performance. The total score was used to develop final ASR suitability maps. The highest score of 142 out of 160 (89% ASR suitability) was achieved in Al Khrair site followed by Al Dhahir with 138 out of 160 (86%), Al Shuwaib with 136 out of 160 (85%) and Al Bateen with 126 out of 160 (79%). The sites located at the eastern part of the study area had the highes scores. The score is decreased at the sites located at the western and southern parts of the study area, with the lowest score of 107 out of 160 at Abu Huraibah. The characterization of sites should be mainly based on the availability of pumping stations in the vicinity of the study area, that will be helpful in the future implementation of the ASR project. The detailed hydrogeological and operational data of the studied sites helped in the ASR assessment.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain
Land use land cover change Remote sensing Groundwater mapping Urbanisation causes land degradatio... more Land use land cover change Remote sensing Groundwater mapping Urbanisation causes land degradation problems, including an increased pressure on natural resources and management of water resources. This study aims to investigate the impact of the spatio-temporal dynamics of land use land cover (LULC) changes on groundwater table in the region of Al Ain, United Arab Emirates (UAE), from 2006 to 2016. The Landsat images, Landsat ETM for 2006 and Landsat 8 for 2016, were acquired from the earth explorer site. A semi-supervised hybrid classification method was used for image classification and postclassification techniques for LULC change detection. The study area was categorised into six major LULC classes. These are agriculture/farms/oasis, gardens/playgrounds, urban areas, sandy areas, lake and mixed urban/ sandy areas. Accuracy assessment of LULC were evaluated using confusion matrix and ground truthing. The obtained land use and land cover maps were also correlated with spatial groundwater table maps prepared with groundwater data. It was found that agriculture/farms/oasis and urban areas expanded from 42,560 ha to 45,950 ha (7.38%) and from 8150 ha to 9105 ha (10.49%) from 2006 to 2016, respectively. The corresponding water demand was increased by 9.56% and 22.22%, respectively. Natural sandy area was found to decrease by 8.10%. As groundwater is major source of water for agriculture in this region, the spatial maps also revealead average declining rate of groundwater depth 40.44% with expansion of urban and agricultural areas over the last 10 years. The outcomes of the study would help concerning authorities for a sustainable management of its land and groundwater resources.
Groundwater is more prone to contamination due to its extensive usage. Different methods are appl... more Groundwater is more prone to contamination due to its extensive usage. Different methods are applied to study vulnerability of groundwater including widely used DRASTIC method, SI and GOD. This study proposes a novel method of mapping groundwater vulnerability using machine learning algorithms. In this study, point extraction method was used to extract point values from a grid of 646 points of seven raster layer in the Al Khatim study area of United Arab Emirates. These extracted values were classified based on nitrate concentration threshold of 50 mg/L into two classes. Machine learning models were developed, using depth to water (D), recharge (R), aquifer media (A), soil media (S), topography (T), vadose zone (I) and hydraulic conductivity (C), on the basis of nitrate class. Classified 'groundwater vulnerability class values' were trained using 10-fold cross-validation, using four machine learning models which were Random Forest, Support Vector Machine, Naïve Bayes and C4. 5. Accuracy showed the model developed by Random Forest gained highest accuracy of 93%. Four groundwater vulnerability maps were developed from machine learning classifiers and was compared with base method of DRASTIC index. The efficiency, accuracy and validity of machine learning based models were evaluated based on Receiver Operating Characteristics (ROC) curve and Precision-Recall curve (PRC). The results proved that machine learning is an efficient tool to access, analyze and map groundwater vulnerability.
The Gulf Cooperation Council (GCC) countries, which consist of Bahrain, Kuwait, Oman, Qatar, Saud... more The Gulf Cooperation Council (GCC) countries, which consist of Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates, possess abundant oil resources but scarce water resources. Low rainfall and high evaporation rates threaten sustainable development in this region. Currently, water demands for domestic and industrial sectors in these countries are mostly met by non-conventional resources such as desalinated water and treated wastewater. In order to augment the freshwater resources, better water management planning, with suitable assessment tools, is necessary. The use of stable and radioactive environmental isotopes has proven to be a powerful assessment tool in many hydrological problems. Combination of previous isotopic and hydrological studies of the Arabian Peninsula could provide an insight on the dynamics of natural processes affecting this water-scarce region. This paper groups many of these studies into various categories based on their objectives, including identification of recharge areas, assessment of groundwater dynamics, and estimation of groundwater age and residence time. Results of previous isotope studies in the GCC countries are put together to identify the sources of precipitation and estimate rates of evaporation, which is the major cause of water loss in these countries. Mediterranean Sea is the major source of vapor for all GCC countries. Local moisture in the UAE is derived from the Arabian Sea and the Indian Ocean, whereas in Saudi Arabia it either originates from the Atlantic Ocean, the Arabian Sea, or the Indian Ocean. Evaporation alters the isotopic composition of groundwater which is mainly controlled by relative humidity that varies between 20% and 90% in the GCC countries. The slope of the evaporation line, compared to Local Meteoric Water Lines (LMWLs), for Bahrain, Kuwait and northern Oman indicates a moderate rate of evaporation due to rapid infiltration of storm water. In contrast, the evaporation line slope for Qatar, southern Oman and Saudi Arabia are higher than the slopes of the LMWLs showing a relatively low rate of evaporation. The UAE groundwater slope is smaller than that of LMWL indicating high evaporation rate of surface water prior to infiltration. The age of groundwater in the GCC countries indicates residence time since late Pleistocene and early Holocene. Hydrochemical data show that groundwater in the GCC countries is contaminated due to evaporation, irrigation return flow and saltwater intrusion.
Groundwater constitutes an important part of the available water resources in arid areas. Knowled... more 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.
Assessing the current levels of greenhouse gas (GHG) emissions from road transportation projects ... more Assessing the current levels of greenhouse gas (GHG) emissions from road transportation projects allows for benchmarking and is essential for potential emissions reduction. The objective of this study was to estimate the GHG emissions associated with the construction and operation of three road cases-two primary roads and one secondary road network-in Abu Dhabi, United Arab Emirates. The GHG emissions produced by the study cases were estimated using the RoadCO 2 estimation tool. Results showed that the total emissions (in kg CO 2 e/m 2 /y) range from 76 for the secondary road case to 1100 for the primary road cases. The operation phase is responsible for 94-98% of these emissions; the construction phase is responsible for the rest. Road works contributed the most to GHG emissions during the construction phase. The contribution of the remaining categories of the construction phase fluctuates within a certain case and among the considered cases. The equipment used in the construction phase for the three cases contributed 15-70% of the total phase emissions, while the remaining emissions were due to construction materials. In the operation phase, emissions were mainly generated by vehicle movement. Street lighting also contributed to emissions during the operation phase. On the other hand, the irrigation of planted trees along the road had a very low impact on GHG emissions, and carbon sequestration by these trees had a negligible effect in terms of acting as a carbon sink. The results obtained from this study were compared with other cases reported in the literature.
The expected increase in the world's population from 2000 to 2020 was about 50% in Africa, 25% in... more The expected increase in the world's population from 2000 to 2020 was about 50% in Africa, 25% in Asia, 14% in the United States, and À2% in Europe (Dore, 2005). This increase is coupled with an increase in water demand. However, industrial and domestic water demand increased twice compared to the rate of population increase. This, of course, is adding pressure on the already limited freshwater resources. On earth, about 3% of the total 1360 million km 3 of water present is fresh water. Out of this, only 1% of water is within human reach and only 0.3% is considered renewable (Dore, 2005). With this limited available freshwater resource and due to variation in its distribution, one out of four persons on earth is suffering from an inadequate supply of fresh water. The United Nations predicted that "about 7 billion people in 48 countries will face water stress or conditions of scarcity by the middle of the century" (Hameeteman, 2013). Scarcity in water resources is amplified given that the available natural water resources are increasingly exposed to pollution. Pollution could be induced in the form of saltwater intrusion due to overexploitation of groundwater reserves, discharge of untreated wastewater into water bodies, lack of proper sewage collection, excessive use of pesticides, leakage of oil pipelines, or degradation of the quality of rainfall due to air pollution or many other forms of induced pollutants in the environment. "The quality of water is as important as its quantity" (Mohamed et al., 2005). The salinity (a measure of the level of total dissolved solids [TDS]) of water available on earth is up to 10,000 mgL À1 , whereas salinity of seawater is in the range of 35,000e45,000 mgL À1 (Eltawil et al., 2009). However, the World Health Organization sets a standard of permissible limits of salinity in drinking water that ranges between 500 and 1000 mgL À1 (WHO, 2004). Given that freshwater resources are almost exhausted in many countries, a study by Clarke (2013) points to the scarcity of water and its degraded quality in several European countries,
Uploads
Papers by Qasim Khan
contaminated due to evaporation, irrigation return flow and saltwater intrusion.
Books by Qasim Khan
contaminated due to evaporation, irrigation return flow and saltwater intrusion.