During the Environmental Impact Assessment procedure (EIA) for hydropower projects, apart from the compliance with environmental standards and regulations, important environmental and ecosystem changes are foreseen fr...During the Environmental Impact Assessment procedure (EIA) for hydropower projects, apart from the compliance with environmental standards and regulations, important environmental and ecosystem changes are foreseen from planning and construction stages. In Mexico, the EIA and environmental standards are being systematically applied and fulfilled at planning and construction stages for hydropower projects. These are mainly related to control air emissions, solid and hazardous wastes, water discharges and deal with protected species. In addition, due to land use changes, forestry compensation procedures have already been established. To comply with project approval conditions, an Environmental Management Plan (EMP) is carried out during construction;it includes mitigation measures, standards, regulations and approval conditions resulting of project review and in some cases requests from the public audience. Monitoring is carried out in the area of influence that is in the works and where it is expected that natural processes are modified. However, indicators to track these changes are minimal. This paper analyzes the regulatory and organizational frameworks to address environmental management during the planning and construction of hydropower facilities in Mexico and gives recommendations to expand the scope of the supervision and management of ecosystem changes.展开更多
A formula for the calculation of critical shear stress of non-uniform sediment was developed by on river bed has been established while considering the relative degree expose of grains.The values of the Coeffi- cients...A formula for the calculation of critical shear stress of non-uniform sediment was developed by on river bed has been established while considering the relative degree expose of grains.The values of the Coeffi- cients in the formula have been obtained.The formula has been verified with prototype observation data, flumes data of both nature and lightweight sand.The computed results fully reflect the characteristics of thresh- old motion of non-uniform sediment.The result have been used in some physical mo...展开更多
The Upper Lillooet River Hydroelectric Project （ULHP） is a run-of-river power generation scheme located near Pemberton, British Columbia, Canada, consisting of two separate hydroelectric facilities （HEFs） with a c...The Upper Lillooet River Hydroelectric Project （ULHP） is a run-of-river power generation scheme located near Pemberton, British Columbia, Canada, consisting of two separate hydroelectric facilities （HEFs） with a combined capacity of 106.7 MW. These HEFs are owned by the Upper Lillooet River Power Limited Partnership and the Boulder Creek Power Limited Partnership, and civil and tunnel construction was completed by CRT-ebc. The Upper Lillooet River HEF includes the excavation ofa 6 m wide by 5.5 m high and approximately 2500 m long tunnel along the Upper Lillooet River Valley. The project is in a moun- tainous area; severe restrictions imposed by weather conditions and the presence of sensitive wildlife species constrained the site operations in order to limit environmental impacts. The site is adjacent to the Mount Meager Volcanic Complex, the most recently active volcano in Western Canada. Tunneling conditions were very challenging, including a section through deposits associated with the most recent eruption from Mount Meager Volcanic Complex （-2360 years before the present）. This tunnel section included welded breccia and unconsolidated deposits composed of loose pumice, organics （that represent an old forest floor）, and till, before entering the underlying tonalite bedrock. The construction of this section of the tunnel required cover grouting, umbrella support, and excavation with a combination of road header, hydraulic hammer, and drilling-and-blasting method. This paper provides an overview of the project, a summary of the key design and construction schedule challenges, and a description of the successful excavation of the tunnel through deposits associated with the recent volcanic activity.展开更多
文摘During the Environmental Impact Assessment procedure (EIA) for hydropower projects, apart from the compliance with environmental standards and regulations, important environmental and ecosystem changes are foreseen from planning and construction stages. In Mexico, the EIA and environmental standards are being systematically applied and fulfilled at planning and construction stages for hydropower projects. These are mainly related to control air emissions, solid and hazardous wastes, water discharges and deal with protected species. In addition, due to land use changes, forestry compensation procedures have already been established. To comply with project approval conditions, an Environmental Management Plan (EMP) is carried out during construction;it includes mitigation measures, standards, regulations and approval conditions resulting of project review and in some cases requests from the public audience. Monitoring is carried out in the area of influence that is in the works and where it is expected that natural processes are modified. However, indicators to track these changes are minimal. This paper analyzes the regulatory and organizational frameworks to address environmental management during the planning and construction of hydropower facilities in Mexico and gives recommendations to expand the scope of the supervision and management of ecosystem changes.
基金Supported by Doctorial Fund of Ministry of Education (2002-173) and (2003-172)
文摘A formula for the calculation of critical shear stress of non-uniform sediment was developed by on river bed has been established while considering the relative degree expose of grains.The values of the Coeffi- cients in the formula have been obtained.The formula has been verified with prototype observation data, flumes data of both nature and lightweight sand.The computed results fully reflect the characteristics of thresh- old motion of non-uniform sediment.The result have been used in some physical mo...
文摘The Upper Lillooet River Hydroelectric Project （ULHP） is a run-of-river power generation scheme located near Pemberton, British Columbia, Canada, consisting of two separate hydroelectric facilities （HEFs） with a combined capacity of 106.7 MW. These HEFs are owned by the Upper Lillooet River Power Limited Partnership and the Boulder Creek Power Limited Partnership, and civil and tunnel construction was completed by CRT-ebc. The Upper Lillooet River HEF includes the excavation ofa 6 m wide by 5.5 m high and approximately 2500 m long tunnel along the Upper Lillooet River Valley. The project is in a moun- tainous area; severe restrictions imposed by weather conditions and the presence of sensitive wildlife species constrained the site operations in order to limit environmental impacts. The site is adjacent to the Mount Meager Volcanic Complex, the most recently active volcano in Western Canada. Tunneling conditions were very challenging, including a section through deposits associated with the most recent eruption from Mount Meager Volcanic Complex （-2360 years before the present）. This tunnel section included welded breccia and unconsolidated deposits composed of loose pumice, organics （that represent an old forest floor）, and till, before entering the underlying tonalite bedrock. The construction of this section of the tunnel required cover grouting, umbrella support, and excavation with a combination of road header, hydraulic hammer, and drilling-and-blasting method. This paper provides an overview of the project, a summary of the key design and construction schedule challenges, and a description of the successful excavation of the tunnel through deposits associated with the recent volcanic activity.
