AM
A.E. Mynett
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1
Ecological Modelling of River-Wetland Systems
A Case Study for the Abras de Mantequilla Wetland in Ecuador
Wetlands are among the most productive environments in the world. Around 6% of the Earth's land surface is covered by wetlands, which are key to preserving biodiversity. Wetlands provide multiple services like a source for water supply and a shelter for numerous species of fauna and flora. Wetlands are therefore of immense socio-economic as well as ecological importance. In this research the focus was on the Abras de Mantequilla (AdM) wetland, a tropical wetland system that belongs to the most important coastal river basin of Ecuador. It was declared a Ramsar site in 2000 and was the South American case of the EU-FP7 WETwin project, which provided the starting point of this thesis. A range of tools and approaches was used to develop a knowledge base for the AdM wetland. The research involved a combination of primary data collection (two fieldwork campaigns), secondary data acquisition (from literature), multivariate analyses, and numerical modelling approaches to explore the characteristics of the wetland system in terms of hydrological conditions, hydrodynamic patterns, biotic communities, chemical and ecological processes and fish-habitat suitability.
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Wetlands are among the most productive environments in the world. Around 6% of the Earth's land surface is covered by wetlands, which are key to preserving biodiversity. Wetlands provide multiple services like a source for water supply and a shelter for numerous species of fauna and flora. Wetlands are therefore of immense socio-economic as well as ecological importance. In this research the focus was on the Abras de Mantequilla (AdM) wetland, a tropical wetland system that belongs to the most important coastal river basin of Ecuador. It was declared a Ramsar site in 2000 and was the South American case of the EU-FP7 WETwin project, which provided the starting point of this thesis. A range of tools and approaches was used to develop a knowledge base for the AdM wetland. The research involved a combination of primary data collection (two fieldwork campaigns), secondary data acquisition (from literature), multivariate analyses, and numerical modelling approaches to explore the characteristics of the wetland system in terms of hydrological conditions, hydrodynamic patterns, biotic communities, chemical and ecological processes and fish-habitat suitability.
The role of small hydropower is becoming increasingly important on a global level. Increasing energy demand and environmental awareness has further triggered research and development into sustainable low cost technologies. In developing countries, particularly in rural areas, local power generation could considerably improve living conditions. With this in mind, the development of a next generation low head hydropower machines was subject of investigation in the EU-project HYLOW. Being part of the research lines of that project, this thesis presents a numerical modelling approach to improve the design of machines like water wheels for increased hydraulic efficiency. Nowadays, Computational Fluid Dynamics (CFD) enables numerical models to be quite accurate and incorporate physical complexities like free surfaces and rotating machines. The results of the CFD simulations carried out in this research show that a change in blade geometry can result in higher torque levels, thereby increasing performance. Numerical simulations also enabled to determine the optimal wheel-width to channel-width ratio and further improve performance by modifying the channel bed conditions upstream and downstream of the water wheel. With a power rating in the low kilowatt range, low-head hydropower machines like optimised water wheels seem to have a clear potential for small-scale energy generation, thereby contributing to achieving the Sustainable Development Goals by providing local energy solutions.
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The role of small hydropower is becoming increasingly important on a global level. Increasing energy demand and environmental awareness has further triggered research and development into sustainable low cost technologies. In developing countries, particularly in rural areas, local power generation could considerably improve living conditions. With this in mind, the development of a next generation low head hydropower machines was subject of investigation in the EU-project HYLOW. Being part of the research lines of that project, this thesis presents a numerical modelling approach to improve the design of machines like water wheels for increased hydraulic efficiency. Nowadays, Computational Fluid Dynamics (CFD) enables numerical models to be quite accurate and incorporate physical complexities like free surfaces and rotating machines. The results of the CFD simulations carried out in this research show that a change in blade geometry can result in higher torque levels, thereby increasing performance. Numerical simulations also enabled to determine the optimal wheel-width to channel-width ratio and further improve performance by modifying the channel bed conditions upstream and downstream of the water wheel. With a power rating in the low kilowatt range, low-head hydropower machines like optimised water wheels seem to have a clear potential for small-scale energy generation, thereby contributing to achieving the Sustainable Development Goals by providing local energy solutions.
The Ning-Meng reach of the Yellow River basin is located in the Inner Mongolia region at the Northern part of the Yellow River. Due to the special geographical conditions, the river flow direction is towards the North causing the Ning-Meng reach to freeze up every year in wintertime. Both during the freeze-up and break-up period, unfavourable conditions occur which may cause ice jamming and ice dam formation leading to dike breaching and overtopping of the embankment. Throughout history this has often led to considerable casualties and property loss. Enhanced economic development and human activities in the
region have altered the characteristics of the ice regime in recent decades, leading to several ice disasters during freezing or breaking-up periods. The integrated water resources management plan developed by the Yellow River Conservancy Commission (YRCC) outlines the requirements for water regulation in the upper Yellow River during ice flood periods. YRCC is developing measures that not only safeguard against ice floods, but also assure the availability of
adequate water resources. These provide the overall requirements for developing an ice regime forecasting system including lead-time prediction and required accuracy. In order to develop such a system, numerical modelling of ice floods is an essential component of current research at the YRCC, together with
field observations and laboratory experiments. In order to properly model river ice processes it is necessary to adjust the hydrodynamic equations to account for thermodynamic effects. In this research, hydrological and meteorological data from 1950 to 2010 were used to analyse the characteristics of ice regimes in the past. Also, additional field observations were carried out for ice
flood model calibration and validation. By combining meteorological forecasting models with statistical models, a medium to short range air temperature forecasting model for the Ning-Meng reach was established. These results were used to improve ice formation modelling and prolong lead-time prediction. The numerical ice flood model developed in this thesis for the Ning-Meng reach allows better forecasting of the ice regime and improved decision support for upstream reservoir regulation and taking appropriate measures for disaster risk reduction. ...
region have altered the characteristics of the ice regime in recent decades, leading to several ice disasters during freezing or breaking-up periods. The integrated water resources management plan developed by the Yellow River Conservancy Commission (YRCC) outlines the requirements for water regulation in the upper Yellow River during ice flood periods. YRCC is developing measures that not only safeguard against ice floods, but also assure the availability of
adequate water resources. These provide the overall requirements for developing an ice regime forecasting system including lead-time prediction and required accuracy. In order to develop such a system, numerical modelling of ice floods is an essential component of current research at the YRCC, together with
field observations and laboratory experiments. In order to properly model river ice processes it is necessary to adjust the hydrodynamic equations to account for thermodynamic effects. In this research, hydrological and meteorological data from 1950 to 2010 were used to analyse the characteristics of ice regimes in the past. Also, additional field observations were carried out for ice
flood model calibration and validation. By combining meteorological forecasting models with statistical models, a medium to short range air temperature forecasting model for the Ning-Meng reach was established. These results were used to improve ice formation modelling and prolong lead-time prediction. The numerical ice flood model developed in this thesis for the Ning-Meng reach allows better forecasting of the ice regime and improved decision support for upstream reservoir regulation and taking appropriate measures for disaster risk reduction. ...
The Ning-Meng reach of the Yellow River basin is located in the Inner Mongolia region at the Northern part of the Yellow River. Due to the special geographical conditions, the river flow direction is towards the North causing the Ning-Meng reach to freeze up every year in wintertime. Both during the freeze-up and break-up period, unfavourable conditions occur which may cause ice jamming and ice dam formation leading to dike breaching and overtopping of the embankment. Throughout history this has often led to considerable casualties and property loss. Enhanced economic development and human activities in the
region have altered the characteristics of the ice regime in recent decades, leading to several ice disasters during freezing or breaking-up periods. The integrated water resources management plan developed by the Yellow River Conservancy Commission (YRCC) outlines the requirements for water regulation in the upper Yellow River during ice flood periods. YRCC is developing measures that not only safeguard against ice floods, but also assure the availability of
adequate water resources. These provide the overall requirements for developing an ice regime forecasting system including lead-time prediction and required accuracy. In order to develop such a system, numerical modelling of ice floods is an essential component of current research at the YRCC, together with
field observations and laboratory experiments. In order to properly model river ice processes it is necessary to adjust the hydrodynamic equations to account for thermodynamic effects. In this research, hydrological and meteorological data from 1950 to 2010 were used to analyse the characteristics of ice regimes in the past. Also, additional field observations were carried out for ice
flood model calibration and validation. By combining meteorological forecasting models with statistical models, a medium to short range air temperature forecasting model for the Ning-Meng reach was established. These results were used to improve ice formation modelling and prolong lead-time prediction. The numerical ice flood model developed in this thesis for the Ning-Meng reach allows better forecasting of the ice regime and improved decision support for upstream reservoir regulation and taking appropriate measures for disaster risk reduction.
region have altered the characteristics of the ice regime in recent decades, leading to several ice disasters during freezing or breaking-up periods. The integrated water resources management plan developed by the Yellow River Conservancy Commission (YRCC) outlines the requirements for water regulation in the upper Yellow River during ice flood periods. YRCC is developing measures that not only safeguard against ice floods, but also assure the availability of
adequate water resources. These provide the overall requirements for developing an ice regime forecasting system including lead-time prediction and required accuracy. In order to develop such a system, numerical modelling of ice floods is an essential component of current research at the YRCC, together with
field observations and laboratory experiments. In order to properly model river ice processes it is necessary to adjust the hydrodynamic equations to account for thermodynamic effects. In this research, hydrological and meteorological data from 1950 to 2010 were used to analyse the characteristics of ice regimes in the past. Also, additional field observations were carried out for ice
flood model calibration and validation. By combining meteorological forecasting models with statistical models, a medium to short range air temperature forecasting model for the Ning-Meng reach was established. These results were used to improve ice formation modelling and prolong lead-time prediction. The numerical ice flood model developed in this thesis for the Ning-Meng reach allows better forecasting of the ice regime and improved decision support for upstream reservoir regulation and taking appropriate measures for disaster risk reduction.
In the Andes mountainous region of South America grasslands known as páramos provide important ecosystem services like sustaining biodiversity, securing carbon sequestration and providing water storage. However, many páramos regions are subject to land use change due to expanding agriculture, intensified grazing and land burning. These are usually caused by socio-economic factors driving local communities to increase their income generation. Trying to achieve a better understanding of the páramos is often restricted to exploring specific details and does not follow an integrated approach or a comprehensive ecosystem analysis. In this research the focus is on better understanding the dominant ecohydrological processes and their interactions. An integrated approach is followed using in-situ measurements, field experiments, laboratory analyses, and numerical modelling. Also, different hydroinformatics tools are used to identify and quantify the ecosystem services provided by the páramos. Moreover, a framework is developed that allows a more realistic quantification and mapping of the main ecosystem services. The approach was carried out for a test site in an Ecological area in North Ecuador. The findings show a clear difference in ecosystem services depending on their altitudinal range and type of vegetation. These results can be used to further develop environmental management and landscape planning strategies, in order to better meet the social goals. This research is aligned with the priorities advocated in the IPCC Report (2007) ‘to improve representation of the interactive coupling between ecosystems and the climate system’, and with SDG #15: Life on Land ‘By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services’.
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In the Andes mountainous region of South America grasslands known as páramos provide important ecosystem services like sustaining biodiversity, securing carbon sequestration and providing water storage. However, many páramos regions are subject to land use change due to expanding agriculture, intensified grazing and land burning. These are usually caused by socio-economic factors driving local communities to increase their income generation. Trying to achieve a better understanding of the páramos is often restricted to exploring specific details and does not follow an integrated approach or a comprehensive ecosystem analysis. In this research the focus is on better understanding the dominant ecohydrological processes and their interactions. An integrated approach is followed using in-situ measurements, field experiments, laboratory analyses, and numerical modelling. Also, different hydroinformatics tools are used to identify and quantify the ecosystem services provided by the páramos. Moreover, a framework is developed that allows a more realistic quantification and mapping of the main ecosystem services. The approach was carried out for a test site in an Ecological area in North Ecuador. The findings show a clear difference in ecosystem services depending on their altitudinal range and type of vegetation. These results can be used to further develop environmental management and landscape planning strategies, in order to better meet the social goals. This research is aligned with the priorities advocated in the IPCC Report (2007) ‘to improve representation of the interactive coupling between ecosystems and the climate system’, and with SDG #15: Life on Land ‘By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services’.