Berms are one of the natural barriers protecting beaches from wave action and are the first inter... more Berms are one of the natural barriers protecting beaches from wave action and are the first intermittently exposed coastal feature to experience hydrodynamic forcing. Berms erode when storm activity mobilizes sediment offshore or carries it onshore through overwash. However, berm response under varied storm conditions requires further study. Pore water pressure response has been shown to potentially impact beach erosion (Stark, 2022). The infiltration from wave runup followed by exfiltration from rundown destabilize the sediment bed resulting in particle motion. Wave runup increases bed shear stress (Sumer, 2011), and horizontal pressure gradients have been shown to mobilize sediment in the surf zone (e.g. Anderson, 2017). Erosion occurs from numerous physical processes acting together to mobilize the sediment. This study aims to identify these physical processes and berm response for variety of scaled storm sequences.
Unexploded ordnance (UXO) resulting from past military activity are present in coastal settings. ... more Unexploded ordnance (UXO) resulting from past military activity are present in coastal settings. Mobility of UXO, specifically in the inner surf and swash zones, constitutes a potential risk for the public. Mobility or exposure may increase under energetic events due to enhanced forcing or sediment erosion. Yet, the conditions leading to exposure, burial, or movement of UXO remain poorly understood. A large-scale laboratory wave flume (120 m x 5 m x 5 m) study at the Institut national de la recherche scientifique (INRS) in Quebec City, Canada was carried out from July 7 to September 23, 2022 to quantify surrogate UXO mobility and burial. An undistorted, scaled beach profile from Mantoloking, NJ, USA was constructed using 0.28 mm diameter sand. Eighteen stations were established at roughly 5 m intervals to collect hydrodynamic, sediment process, and morphology data and to quantify surrogate UXO behavior. Over 150 surrogates of varying bulk density were distributed throughout the flum...
Water scarcity is a major challenge around the world, particularly in Ekpoma community, Edo State... more Water scarcity is a major challenge around the world, particularly in Ekpoma community, Edo State, Nigeria. The population depends on water vendors and reservoir tanks as a means of water supply. This study aims to make an assessment of groundwater potentials for effective and sustainable water resources management in Ekpoma. Seven criteria were considered to determine groundwater potentiality including slope, rainfall, land use, drainage density, distance to lineament, soil, and geology. According to their impact on groundwater, the parameters were grouped into fuzzy membership categories. The groundwater potentiality map was generated by overlaying the fuzzy members. Of the 101.2 km2 area of Ekpoma, the high, medium, and low potential zones cover 7.9, 6.4, and 85.7% of the total area, respectively. High and medium groundwater zones were identified mostly on the outskirt of the built-up areas. These groundwater potential areas were discovered to be predominant around the lineament areas suggesting that lineament plays a major role in the potential for groundwater in the study area. Reservoirs can be assigned in these high potential areas. Conclusively, the generated groundwater prospective map can be exploited for hydrological policy making and also by water supply engineers to predict the availability of groundwater.
The yearly volumetric increase in the globe’s oceans and seas leading to “Sea Level Rise” has ... more The yearly volumetric increase in the globe’s oceans and seas leading to “Sea Level Rise” has been a subject of research and debate in recent years. Coastal regions have been most vulnerable to this phenomenon sometimes resulting in serious disasters. Climate change and anthropogenic activities are major causes of many of these disasters. Lagos, the main commercial centre of Nigeria is not an exception. It has a long strip of coastline and wetland regions. However, the wetlands are rapidly declining due to increased pressure for residential and industrial lands. Hence, land reclamation activities have been on the increase in recent years especially in the Victoria Island, Lekki and Ikoyi axes of the state. These are essentially coastlines and wetlands. Despite environmental concerns about increased vulnerability to floods, sea water intrusion, salinization of the freshwater, and a risk of sea water re...
Groundwater pollution in the north coast of Mombasa is not only from surface sources but also fro... more Groundwater pollution in the north coast of Mombasa is not only from surface sources but also from the intrusion of seawater via the Indian Ocean and creeks. This study assessed the vulnerability of the coastal aquifer to seawater intrusion using GALDIT index overlay method with the aid of GIS. Thematic maps of six major factors affecting seawater intrusion were prepared, and given appropriate weightages and ratings. These maps were overlaid, spatially analyzed to produce vulnerability maps and described based on low, moderate or high vulnerabilities. The results revealed a significant increase in percentage land cover for low vulnerability areas and a slight increase for high vulnerability regions between the pre-rains and the peak of raining season. The outcomes of this study provide useful insights on effective groundwater management for the study area.
The continuous degradation of environmental ecosystems (land, water and soil) resulting from crud... more The continuous degradation of environmental ecosystems (land, water and soil) resulting from crude oil exploration and exploitation activities continues to gain global attention. This study investigates the effects of crude oil exploration and exploitation activities on soil, water and air in the study area. Soil samples were collected in three replicates at depths of 0-15 and 15-30 cm at sampling distances of 20 m, 100 m and 200 m a from core oil exploitation operation area and a control point. Water samples were also taken from within the study area and analyzed using standard procedures. Major pollutants concentrations of particulate matter (PM2.5 and PM10) of the air were also measured using Air Quality Index (AQI). The results reveal that the soil, water and air parameters measured mostly at 20 m from the core oil operation area compromise the allowable standards provided for healthy living. In the same manner, some results at 100 and 200 m were slightly higher than the recommended values in some cases of heavy metals and bacteria activities in the soil. The AQI at 20 m was far above the permissible limit provided by the Environmental Protection Agency while others are gradually drawing towards the limit given for each pollutant. To safeguard the health of the residents of the host community and oil field workers, there is a need for proper and frequent environmental monitoring and assessment by authorized regulatory bodies in Nigeria. This will prevent any future exposure which may endanger the lives of the dwellers.
Environmental Science and Pollution Research, 2022
The pressure and dependence on coastal aquifers are on the rise in many parts of the globe. These... more The pressure and dependence on coastal aquifers are on the rise in many parts of the globe. These lead to overexploitation, aggravated levels of groundwater pollution, and seawater intrusion. Integrated analyses can create holistic insights into the quality and the vulnerability of aquifers to seawater intrusion. In this study, Mombasa North coast’s coastal aquifer was characterized by integrating multiple approaches—GALDIT overlay index, seawater intrusion groundwater quality index GQISWI, total hardness, water quality index (WQI)—and the results were further explored and interpreted with geospatial analysis techniques. The study suggests that the predominant water type in areas under moderate or high vulnerabilities to seawater intrusion is the Na-Cl water type. However, similar Na-Cl water types can produce a range of total hardness from soft to hard. GQISWI classification can be used to narrow down the observations from Stuyfzand’s TH-based classification system. In the aquifer studied, the results of the GALDIT overlay index, a weighted aggregation of intrinsic parameters contributing to seawater intrusion, show that 29%, 59%, and 12% of the aquifer have low, moderate, and high vulnerabilities, respectively. The GQISWI analysis indicates that the groundwater is largely brackish (68%) but saline towards the southern end of the aquifer at 32%. Total hardness values indicate that 67% of the aquifer’s coverage falls under the “moderately hard” category. The geodatabase creation introduced in the study provides a template for similar studies and a baseline for future WQI and water quality monitoring. However, temporal studies on chronological timescales are recommended for sustainable management of the aquifer.
The most extensive urban growths in the next 30 years are expected to occur in developing countri... more The most extensive urban growths in the next 30 years are expected to occur in developing countries. Lagos, Nigeria - Africa’s second most populous megacity- is a prime example. To achieve more sustainable and resilient cities, there is a need for modeling the urban growth patterns of major cities and analyzing their implications. In this study, the urban growth of Lagos state was modeled using the Multi-Layer Perceptron (MLP) neural network for the transition modeling and the Markov Chain analysis for the change prediction, achieving a model accuracy of 81.8%. An innovative visual validation of the model results using the ArcGIS was combined with kappa correlation statistics. The results show that by 2031, built-up areas will be the most spatially extensive LULC class in the study area with percentage coverage of 34.1% as opposed to 9% in 1986. The coverage of bare areas is also expected to increase by 53% between 2016 and 2031. Conversely, 24.9% and 68.3% loss of forestlands and ...
Coastal areas have experienced a massive population increase all around the world in recent decad... more Coastal areas have experienced a massive population increase all around the world in recent decades. This has led to significant changes in land use land cover (LULC) with ecosystem patterns and functions also affected. Lagos, a fast rising mega city and de facto commercial and economic capital of Nigeria, characterised by a low-lying coastal strip, swamps, wetlands and lagoon, is a special case. Over the years, there has been a substantial change in the dynamics of land use/ cover of the study area. This study assessed these changes with emphasis laid on changes in wetlands, and built-up areas mainly due to urbanisation and land reclamation activities over a period of 30 years. Landsat images for years 1986 and 2001 were obtained as well as 2016 sentinel 2A images. ENVI software package was used for atmosphere correction, haze detection, layer stacking and classification. A pixel-based supervised classification was used to obtain the LULC maps. Filtering was done to reduce noise i...
As cities expand and more megacities emerge, the impacts on the environment are increasingly beco... more As cities expand and more megacities emerge, the impacts on the environment are increasingly becoming apparent. One of such impacts is the Urban Heat Island (UHI) phenomenon. Several studies have identified progressive vegetation losses and decrease in pervious surfaces as two of the main factors contributing to UHI. However, location-based studies help determine the pertinent contributing factors, thereby providing a valuable basis for the formulation of efficient mitigation strategies in such areas. This study investigated the impact of land cover changes on UHI and its evolution from the year 2000 to 2018 in Nairobi – a major city in East Africa. Medium resolution Landsat TM, ETM+ and OLI data were obtained for assessing the Land cover changes and establishing the relationship between the changes and the corresponding Land Surface Temperatures (LST). The datasets were acquired in intervals of 2002-2010-2018. A pixel-based supervised classification was used for assessing the land ...
Water is an essential natural resource that is vital for sustaining every form of life existence.... more Water is an essential natural resource that is vital for sustaining every form of life existence. Availability of groundwater is spatially and temporally dependent upon the terrain of an area. In order to improve efficiency and effectiveness in water availability, supply and use, the construction of water harvesting structures across streams/watersheds is gaining drive in recent years. The increase in demand for water has led to the construction of water storage dams for various purposes such as community and industrial use, irrigation, flood control, hydropower and river canalization. Safety is the key consideration than cost and capacity as the failure of a dam often results to severe loss of lives and properties, hence the need to consider some important criteria for suitable dam siting. In this study, potential sites for construction of dams in Imo State, Nigeria, have been identified by using geographical information system and remote sensing techniques which were integrated with fuzzy logic to achieve the study objectives. Climatic and geophysical factors such as rainfall, runoff, stream order, soil type, geology type and land use were considered. These factors assigned fuzzy membership classes according to their contribution in locating suitable dam sites. The fuzzy members for all the factors were combined using the fuzzy overlay technique to produce the suitable dam site selection map. Majority of the selected sites were located in the northwestern part of Imo State which is characterized by high elevation and gentle slope.
The most extensive urban growths in the next 30 years are expected to occur in developing countri... more The most extensive urban growths in the next 30 years are expected to occur in developing countries. Lagos, Nigeria - Africa’s second most populous megacity- is a prime example. To achieve more sustainable and resilient cities, there is a need for modeling the urban growth patterns of major cities and analyzing their implications. In this study, the urban growth of Lagos state was modeled using the Multi-Layer Perceptron (MLP) neural network for the transition modeling and the Markov Chain analysis for the change prediction, achieving a model accuracy of 81.8%. An innovative visual validation of the model results using the ArcGIS was combined with kappa correlation statistics. The results show that by 2031, built-up areas will be the most spatially extensive LULC class in the study area with percentage coverage of 34.1% as opposed to 9% in 1986. The coverage of bare areas is also expected to increase by 53% between 2016 and 2031. Conversely, 24.9% and 68.3% loss of forestlands and w...
The geochemistry of a coastal aquifer was assessed using statistical and geospatial analysis tool... more The geochemistry of a coastal aquifer was assessed using statistical and geospatial analysis tools for the pre-monsoon, rainy and post-monsoon seasons. Data were obtained from both the field and laboratory analysis of water samples. Statistical methods such as correlation coefficients, piper plots, factor analysis and mixing index were used to gain insights into the geochemistry, while geospatial tools were used to create contours to understand the spatial distribution of the measured groundwater parameters of the coastal aquifer. The measured groundwater levels ranged from-0.84 to 30.08 m above mean sea level. The Electrical Conductivities and Total Dissolved Solids values were observed to have perfectly correlated with each other. Groundwater salinities were generally high, as over 94% of the water samples tested exceeded the WHO drinking water limit of 750 lS/cm and 500 mg/l, respectively. The groundwater pH was generally slightly alkaline but could be slightly acidic in the rainy season. The Na ? , K ? , Mg 2? , Cland SO 4 2were observed to have high impacts on the geochemistry and also had tendencies to form similar trends. EC, TDS and NaCl values above 1000 mg/l in the groundwater were observed to generally skew towards the ocean during the rainy season. The principal process influencing the geochemistry was found to be seawater intrusion, while mineral dissolutions and rainwater percolation play lesser roles. The aquifer predominantly comprises Na-Cl waters of marine origin. The study shows the growing importance and applicability of integrated statistical and geospatial approaches for better understanding of groundwater and geochemistry of aquifers.
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.
Berms are one of the natural barriers protecting beaches from wave action and are the first inter... more Berms are one of the natural barriers protecting beaches from wave action and are the first intermittently exposed coastal feature to experience hydrodynamic forcing. Berms erode when storm activity mobilizes sediment offshore or carries it onshore through overwash. However, berm response under varied storm conditions requires further study. Pore water pressure response has been shown to potentially impact beach erosion (Stark, 2022). The infiltration from wave runup followed by exfiltration from rundown destabilize the sediment bed resulting in particle motion. Wave runup increases bed shear stress (Sumer, 2011), and horizontal pressure gradients have been shown to mobilize sediment in the surf zone (e.g. Anderson, 2017). Erosion occurs from numerous physical processes acting together to mobilize the sediment. This study aims to identify these physical processes and berm response for variety of scaled storm sequences.
Unexploded ordnance (UXO) resulting from past military activity are present in coastal settings. ... more Unexploded ordnance (UXO) resulting from past military activity are present in coastal settings. Mobility of UXO, specifically in the inner surf and swash zones, constitutes a potential risk for the public. Mobility or exposure may increase under energetic events due to enhanced forcing or sediment erosion. Yet, the conditions leading to exposure, burial, or movement of UXO remain poorly understood. A large-scale laboratory wave flume (120 m x 5 m x 5 m) study at the Institut national de la recherche scientifique (INRS) in Quebec City, Canada was carried out from July 7 to September 23, 2022 to quantify surrogate UXO mobility and burial. An undistorted, scaled beach profile from Mantoloking, NJ, USA was constructed using 0.28 mm diameter sand. Eighteen stations were established at roughly 5 m intervals to collect hydrodynamic, sediment process, and morphology data and to quantify surrogate UXO behavior. Over 150 surrogates of varying bulk density were distributed throughout the flum...
Water scarcity is a major challenge around the world, particularly in Ekpoma community, Edo State... more Water scarcity is a major challenge around the world, particularly in Ekpoma community, Edo State, Nigeria. The population depends on water vendors and reservoir tanks as a means of water supply. This study aims to make an assessment of groundwater potentials for effective and sustainable water resources management in Ekpoma. Seven criteria were considered to determine groundwater potentiality including slope, rainfall, land use, drainage density, distance to lineament, soil, and geology. According to their impact on groundwater, the parameters were grouped into fuzzy membership categories. The groundwater potentiality map was generated by overlaying the fuzzy members. Of the 101.2 km2 area of Ekpoma, the high, medium, and low potential zones cover 7.9, 6.4, and 85.7% of the total area, respectively. High and medium groundwater zones were identified mostly on the outskirt of the built-up areas. These groundwater potential areas were discovered to be predominant around the lineament areas suggesting that lineament plays a major role in the potential for groundwater in the study area. Reservoirs can be assigned in these high potential areas. Conclusively, the generated groundwater prospective map can be exploited for hydrological policy making and also by water supply engineers to predict the availability of groundwater.
The yearly volumetric increase in the globe’s oceans and seas leading to “Sea Level Rise” has ... more The yearly volumetric increase in the globe’s oceans and seas leading to “Sea Level Rise” has been a subject of research and debate in recent years. Coastal regions have been most vulnerable to this phenomenon sometimes resulting in serious disasters. Climate change and anthropogenic activities are major causes of many of these disasters. Lagos, the main commercial centre of Nigeria is not an exception. It has a long strip of coastline and wetland regions. However, the wetlands are rapidly declining due to increased pressure for residential and industrial lands. Hence, land reclamation activities have been on the increase in recent years especially in the Victoria Island, Lekki and Ikoyi axes of the state. These are essentially coastlines and wetlands. Despite environmental concerns about increased vulnerability to floods, sea water intrusion, salinization of the freshwater, and a risk of sea water re...
Groundwater pollution in the north coast of Mombasa is not only from surface sources but also fro... more Groundwater pollution in the north coast of Mombasa is not only from surface sources but also from the intrusion of seawater via the Indian Ocean and creeks. This study assessed the vulnerability of the coastal aquifer to seawater intrusion using GALDIT index overlay method with the aid of GIS. Thematic maps of six major factors affecting seawater intrusion were prepared, and given appropriate weightages and ratings. These maps were overlaid, spatially analyzed to produce vulnerability maps and described based on low, moderate or high vulnerabilities. The results revealed a significant increase in percentage land cover for low vulnerability areas and a slight increase for high vulnerability regions between the pre-rains and the peak of raining season. The outcomes of this study provide useful insights on effective groundwater management for the study area.
The continuous degradation of environmental ecosystems (land, water and soil) resulting from crud... more The continuous degradation of environmental ecosystems (land, water and soil) resulting from crude oil exploration and exploitation activities continues to gain global attention. This study investigates the effects of crude oil exploration and exploitation activities on soil, water and air in the study area. Soil samples were collected in three replicates at depths of 0-15 and 15-30 cm at sampling distances of 20 m, 100 m and 200 m a from core oil exploitation operation area and a control point. Water samples were also taken from within the study area and analyzed using standard procedures. Major pollutants concentrations of particulate matter (PM2.5 and PM10) of the air were also measured using Air Quality Index (AQI). The results reveal that the soil, water and air parameters measured mostly at 20 m from the core oil operation area compromise the allowable standards provided for healthy living. In the same manner, some results at 100 and 200 m were slightly higher than the recommended values in some cases of heavy metals and bacteria activities in the soil. The AQI at 20 m was far above the permissible limit provided by the Environmental Protection Agency while others are gradually drawing towards the limit given for each pollutant. To safeguard the health of the residents of the host community and oil field workers, there is a need for proper and frequent environmental monitoring and assessment by authorized regulatory bodies in Nigeria. This will prevent any future exposure which may endanger the lives of the dwellers.
Environmental Science and Pollution Research, 2022
The pressure and dependence on coastal aquifers are on the rise in many parts of the globe. These... more The pressure and dependence on coastal aquifers are on the rise in many parts of the globe. These lead to overexploitation, aggravated levels of groundwater pollution, and seawater intrusion. Integrated analyses can create holistic insights into the quality and the vulnerability of aquifers to seawater intrusion. In this study, Mombasa North coast’s coastal aquifer was characterized by integrating multiple approaches—GALDIT overlay index, seawater intrusion groundwater quality index GQISWI, total hardness, water quality index (WQI)—and the results were further explored and interpreted with geospatial analysis techniques. The study suggests that the predominant water type in areas under moderate or high vulnerabilities to seawater intrusion is the Na-Cl water type. However, similar Na-Cl water types can produce a range of total hardness from soft to hard. GQISWI classification can be used to narrow down the observations from Stuyfzand’s TH-based classification system. In the aquifer studied, the results of the GALDIT overlay index, a weighted aggregation of intrinsic parameters contributing to seawater intrusion, show that 29%, 59%, and 12% of the aquifer have low, moderate, and high vulnerabilities, respectively. The GQISWI analysis indicates that the groundwater is largely brackish (68%) but saline towards the southern end of the aquifer at 32%. Total hardness values indicate that 67% of the aquifer’s coverage falls under the “moderately hard” category. The geodatabase creation introduced in the study provides a template for similar studies and a baseline for future WQI and water quality monitoring. However, temporal studies on chronological timescales are recommended for sustainable management of the aquifer.
The most extensive urban growths in the next 30 years are expected to occur in developing countri... more The most extensive urban growths in the next 30 years are expected to occur in developing countries. Lagos, Nigeria - Africa’s second most populous megacity- is a prime example. To achieve more sustainable and resilient cities, there is a need for modeling the urban growth patterns of major cities and analyzing their implications. In this study, the urban growth of Lagos state was modeled using the Multi-Layer Perceptron (MLP) neural network for the transition modeling and the Markov Chain analysis for the change prediction, achieving a model accuracy of 81.8%. An innovative visual validation of the model results using the ArcGIS was combined with kappa correlation statistics. The results show that by 2031, built-up areas will be the most spatially extensive LULC class in the study area with percentage coverage of 34.1% as opposed to 9% in 1986. The coverage of bare areas is also expected to increase by 53% between 2016 and 2031. Conversely, 24.9% and 68.3% loss of forestlands and ...
Coastal areas have experienced a massive population increase all around the world in recent decad... more Coastal areas have experienced a massive population increase all around the world in recent decades. This has led to significant changes in land use land cover (LULC) with ecosystem patterns and functions also affected. Lagos, a fast rising mega city and de facto commercial and economic capital of Nigeria, characterised by a low-lying coastal strip, swamps, wetlands and lagoon, is a special case. Over the years, there has been a substantial change in the dynamics of land use/ cover of the study area. This study assessed these changes with emphasis laid on changes in wetlands, and built-up areas mainly due to urbanisation and land reclamation activities over a period of 30 years. Landsat images for years 1986 and 2001 were obtained as well as 2016 sentinel 2A images. ENVI software package was used for atmosphere correction, haze detection, layer stacking and classification. A pixel-based supervised classification was used to obtain the LULC maps. Filtering was done to reduce noise i...
As cities expand and more megacities emerge, the impacts on the environment are increasingly beco... more As cities expand and more megacities emerge, the impacts on the environment are increasingly becoming apparent. One of such impacts is the Urban Heat Island (UHI) phenomenon. Several studies have identified progressive vegetation losses and decrease in pervious surfaces as two of the main factors contributing to UHI. However, location-based studies help determine the pertinent contributing factors, thereby providing a valuable basis for the formulation of efficient mitigation strategies in such areas. This study investigated the impact of land cover changes on UHI and its evolution from the year 2000 to 2018 in Nairobi – a major city in East Africa. Medium resolution Landsat TM, ETM+ and OLI data were obtained for assessing the Land cover changes and establishing the relationship between the changes and the corresponding Land Surface Temperatures (LST). The datasets were acquired in intervals of 2002-2010-2018. A pixel-based supervised classification was used for assessing the land ...
Water is an essential natural resource that is vital for sustaining every form of life existence.... more Water is an essential natural resource that is vital for sustaining every form of life existence. Availability of groundwater is spatially and temporally dependent upon the terrain of an area. In order to improve efficiency and effectiveness in water availability, supply and use, the construction of water harvesting structures across streams/watersheds is gaining drive in recent years. The increase in demand for water has led to the construction of water storage dams for various purposes such as community and industrial use, irrigation, flood control, hydropower and river canalization. Safety is the key consideration than cost and capacity as the failure of a dam often results to severe loss of lives and properties, hence the need to consider some important criteria for suitable dam siting. In this study, potential sites for construction of dams in Imo State, Nigeria, have been identified by using geographical information system and remote sensing techniques which were integrated with fuzzy logic to achieve the study objectives. Climatic and geophysical factors such as rainfall, runoff, stream order, soil type, geology type and land use were considered. These factors assigned fuzzy membership classes according to their contribution in locating suitable dam sites. The fuzzy members for all the factors were combined using the fuzzy overlay technique to produce the suitable dam site selection map. Majority of the selected sites were located in the northwestern part of Imo State which is characterized by high elevation and gentle slope.
The most extensive urban growths in the next 30 years are expected to occur in developing countri... more The most extensive urban growths in the next 30 years are expected to occur in developing countries. Lagos, Nigeria - Africa’s second most populous megacity- is a prime example. To achieve more sustainable and resilient cities, there is a need for modeling the urban growth patterns of major cities and analyzing their implications. In this study, the urban growth of Lagos state was modeled using the Multi-Layer Perceptron (MLP) neural network for the transition modeling and the Markov Chain analysis for the change prediction, achieving a model accuracy of 81.8%. An innovative visual validation of the model results using the ArcGIS was combined with kappa correlation statistics. The results show that by 2031, built-up areas will be the most spatially extensive LULC class in the study area with percentage coverage of 34.1% as opposed to 9% in 1986. The coverage of bare areas is also expected to increase by 53% between 2016 and 2031. Conversely, 24.9% and 68.3% loss of forestlands and w...
The geochemistry of a coastal aquifer was assessed using statistical and geospatial analysis tool... more The geochemistry of a coastal aquifer was assessed using statistical and geospatial analysis tools for the pre-monsoon, rainy and post-monsoon seasons. Data were obtained from both the field and laboratory analysis of water samples. Statistical methods such as correlation coefficients, piper plots, factor analysis and mixing index were used to gain insights into the geochemistry, while geospatial tools were used to create contours to understand the spatial distribution of the measured groundwater parameters of the coastal aquifer. The measured groundwater levels ranged from-0.84 to 30.08 m above mean sea level. The Electrical Conductivities and Total Dissolved Solids values were observed to have perfectly correlated with each other. Groundwater salinities were generally high, as over 94% of the water samples tested exceeded the WHO drinking water limit of 750 lS/cm and 500 mg/l, respectively. The groundwater pH was generally slightly alkaline but could be slightly acidic in the rainy season. The Na ? , K ? , Mg 2? , Cland SO 4 2were observed to have high impacts on the geochemistry and also had tendencies to form similar trends. EC, TDS and NaCl values above 1000 mg/l in the groundwater were observed to generally skew towards the ocean during the rainy season. The principal process influencing the geochemistry was found to be seawater intrusion, while mineral dissolutions and rainwater percolation play lesser roles. The aquifer predominantly comprises Na-Cl waters of marine origin. The study shows the growing importance and applicability of integrated statistical and geospatial approaches for better understanding of groundwater and geochemistry of aquifers.
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.
The yearly volumetric increase in the globe's oceans and seas leading to " Sea Level Rise " has b... more The yearly volumetric increase in the globe's oceans and seas leading to " Sea Level Rise " has been a subject of research and debate in recent years. Coastal regions have been most vulnerable to this phenomenon sometimes resulting in serious disasters. Climate change and anthropogenic activities are major causes of many of these disasters. Lagos, the main commercial centre of Nigeria is not an exception. It has a long strip of coastline and wetland regions. However, the wetlands are rapidly declining due to increased pressure for residential and industrial lands. Hence, land reclamation activities have been on the increase in recent years especially in the Victoria Island, Lekki and Ikoyi axes of the state. These are essentially coastlines and wetlands. Despite environmental concerns about increased vulnerability to floods, sea water intrusion, salinization of the freshwater, and a risk of sea water resurgence into the reclaimed lands, the reclamation activities are increasingly becoming popular. Weak enforcement of Land use policies and inadequate empirical assessment of these activities birthed the need for this in-depth study. This study uses literature from across various disciplines, predictions and reports from monitoring agencies, global organisations, and real-life experiences. Inferences are made from these relevant and up to date information to assess critically and come up with empirical predictions on the probable effects of the land reclamation activities coupled with projected sea level rise. Current projections for Global mean sea level rise is 3.2mm/year, and regional levels could be higher depending on local factors. The findings show that the imminent dangers associated with these activities on low-lying, densely populated and slum areas like Makoko, Iwaya, Ilaje-bariga are far greater and closer than envisaged. This review proffers proactive and pragmatic solutions for stakeholders involved to abate these effects.
Powerpoint presentation on the land-use land cover changes in Lagos between 1986 and 2016 (30 yea... more Powerpoint presentation on the land-use land cover changes in Lagos between 1986 and 2016 (30 years) with emphasis on Built-up areas, wetlands and waterbodies.
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