Keya Hydropower Plant (HPP) is a run-off-river plant which can be an effective green solution contributing to the current energy demand in Rwanda but a huge amount of sediment contained in water of Sebeya River on whi...Keya Hydropower Plant (HPP) is a run-off-river plant which can be an effective green solution contributing to the current energy demand in Rwanda but a huge amount of sediment contained in water of Sebeya River on which this plant is built results in loss of the plant capacity. The aim of this study was to conduct the performance evaluation of Keya HPP sediment basin located in Rubavu district, western province of Rwanda. Specifically, laboratory tests of sediment, efficiency of the basin, assessment of sedimentation problems on HPP operations, proposition of technical options for increasing the removal efficiency of sediment basin and other options for reducing sediment at the source of generation were performed using different methods including interviews and questioning Keya hydropower technicians, field sediment sampling followed by hydrometer and Particle Size Distribution (PSD) analysis. Analysis was made in University of Rwanda (UR) Soil Mechanics laboratory. MICROSOFT EXCEL and Graphisoft Archicad 18 softwares with Massachusetts Institute of Technology (MIT) soil classification were used as data analysis tools. Results showed that the overall efficiency removal of the diversion headwork was 85%. However, after comparing sediment concentration at the inlet and outlet of the sediment basin, it was found that the basin removed only 22% of sediment from diverted water toward the turbine. This means that 78% of sediment escapes the basin to cause erosion on the turbine components resulting in reduction of the plant capacity from 2.2 MW to 900 KW. To ensure sustainable solution to sediment issues in Keya HPP, an upstream sediment trap reservoir is proposed. It is recommended also that Rwanda Energy Group (REG) should work together with Rwanda Natural Resource Authority (RNRA) at national level to ensure sustainable development of erosion control in the Sebeya catchment area.展开更多
基于CMIP6未来情景下的气候变化通过耦合FLUS模型,运用InVEST模型、CASA模型分析研究区的水源涵养、固碳释氧、土壤保持价值时空变化趋势,并利用R语言、GeoDa模型对研究区生态系统服务价值进行空间异质性分析。结果表明:在SSP245、SSP58...基于CMIP6未来情景下的气候变化通过耦合FLUS模型,运用InVEST模型、CASA模型分析研究区的水源涵养、固碳释氧、土壤保持价值时空变化趋势,并利用R语言、GeoDa模型对研究区生态系统服务价值进行空间异质性分析。结果表明:在SSP245、SSP585情景下单位面积水源涵养价值分别为17.34万元/km^(2)、14.28万元/km^(2);单位面积固碳释氧价值分别为107.13万元/km^(2)、101.75万元/km^(2);单位面积土壤保持价值分别为40.18万元/km^(2)、44.61万元/km^(2)。本研究结论:在未来情景下,生态系统服务价值总体呈增加趋势,SSP245情景下生态系统服务价值增加幅度更大;全局Moran s I指数整体呈波动增加趋势,其中土壤保持、水源涵养功能在空间上具有较高聚集性,固碳释氧功能聚集性相对较差,研究区北部生态系统服务价值聚集性更高;研究区内生态系统服务价值均呈协同关系,未来情景下整体协同值呈增加趋势。厘清生态子系统之间的依赖关系,形成更完善的代谢循环,对于生态系统的稳定性以及可持续发展具有重要意义。展开更多
文摘Keya Hydropower Plant (HPP) is a run-off-river plant which can be an effective green solution contributing to the current energy demand in Rwanda but a huge amount of sediment contained in water of Sebeya River on which this plant is built results in loss of the plant capacity. The aim of this study was to conduct the performance evaluation of Keya HPP sediment basin located in Rubavu district, western province of Rwanda. Specifically, laboratory tests of sediment, efficiency of the basin, assessment of sedimentation problems on HPP operations, proposition of technical options for increasing the removal efficiency of sediment basin and other options for reducing sediment at the source of generation were performed using different methods including interviews and questioning Keya hydropower technicians, field sediment sampling followed by hydrometer and Particle Size Distribution (PSD) analysis. Analysis was made in University of Rwanda (UR) Soil Mechanics laboratory. MICROSOFT EXCEL and Graphisoft Archicad 18 softwares with Massachusetts Institute of Technology (MIT) soil classification were used as data analysis tools. Results showed that the overall efficiency removal of the diversion headwork was 85%. However, after comparing sediment concentration at the inlet and outlet of the sediment basin, it was found that the basin removed only 22% of sediment from diverted water toward the turbine. This means that 78% of sediment escapes the basin to cause erosion on the turbine components resulting in reduction of the plant capacity from 2.2 MW to 900 KW. To ensure sustainable solution to sediment issues in Keya HPP, an upstream sediment trap reservoir is proposed. It is recommended also that Rwanda Energy Group (REG) should work together with Rwanda Natural Resource Authority (RNRA) at national level to ensure sustainable development of erosion control in the Sebeya catchment area.
文摘基于CMIP6未来情景下的气候变化通过耦合FLUS模型,运用InVEST模型、CASA模型分析研究区的水源涵养、固碳释氧、土壤保持价值时空变化趋势,并利用R语言、GeoDa模型对研究区生态系统服务价值进行空间异质性分析。结果表明:在SSP245、SSP585情景下单位面积水源涵养价值分别为17.34万元/km^(2)、14.28万元/km^(2);单位面积固碳释氧价值分别为107.13万元/km^(2)、101.75万元/km^(2);单位面积土壤保持价值分别为40.18万元/km^(2)、44.61万元/km^(2)。本研究结论:在未来情景下,生态系统服务价值总体呈增加趋势,SSP245情景下生态系统服务价值增加幅度更大;全局Moran s I指数整体呈波动增加趋势,其中土壤保持、水源涵养功能在空间上具有较高聚集性,固碳释氧功能聚集性相对较差,研究区北部生态系统服务价值聚集性更高;研究区内生态系统服务价值均呈协同关系,未来情景下整体协同值呈增加趋势。厘清生态子系统之间的依赖关系,形成更完善的代谢循环,对于生态系统的稳定性以及可持续发展具有重要意义。
