对大型水坝工程的生态反思

人类正在以更加崭新的视角,重新思考水坝建设带来的诸多问题。以往为解决因建造水库对生态系统和野生物种保护造成不良影响的行动,并没有获得长期性的成功。由于传统的生态补救措施一般不佳,因此越来越多的国家开始寻求新的解决途径。

3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation

Accurate 3-D fracture network model for rock mass in dam foundation is of vital importance for stability,grouting and seepage analysis of dam foundation.With the aim of reducing deviation between fracture network model and measured data,a 3-D fracture network dynamic modeling method based on error analysis was proposed.Firstly,errors of four fracture volume density estimation methods(proposed by ODA,KULATILAKE,MAULDON,and SONG)and that of four fracture size estimation methods(proposed by EINSTEIN,SONG and TONON)were respectively compared,and the optimal methods were determined.Additionally,error index representing the deviation between fracture network model and measured data was established with integrated use of fractal dimension and relative absolute error(RAE).On this basis,the downhill simplex method was used to build the dynamic modeling method,which takes the minimum of error index as objective function and dynamically adjusts the fracture density and size parameters to correct the error index.Finally,the 3-D fracture network model could be obtained which meets the requirements.The proposed method was applied for 3-D fractures simulation in Miao Wei hydropower project in China for feasibility verification and the error index reduced from 2.618 to 0.337.

The Experience of Regional Planning of the CESP （Companhia Energetica de Sao Paulo）, Brazil

This article deals with the important experience of regional planning developed by the CESP （Companhia Energ6tica de Silo Paulo）, Brazil, through the implantation of its hydroelectric projects. The company accumulated a large experience in deploying and managing residential centers built to provide support to the works of their dams. The presence of urban planning was verified in all cases studied, with the participation of different professionals such as architects, planners, engineers and landscape designers, from inside or outside the company. This research shows that they used concepts derived from experiences as company towns of 19th century, the neighborhood unit, the garden city, the urbanistic assumptions from CIAM （Congr^s Internationaux d＇Architecture Moderne） and the TVA （Tennessee Valley Authority）.

Possibilities of Using Dam Reservoir Sediments in Earthworks

A possibility of using bottom sediments from dam reservoir as a material for earthen embankments was considered in the paper. It was stated that sediments cannot be used for road or hydrotechnical embankments without improving their geotechnical parameters. Thanks to low values of the permeability coefficient, they can be used for sealing elements in embankments or for low levees. In order to verify usability of this material for mentioned levees, stability and filtration calculations were carried out using Finite Element Method （FEM） analysis. It was stated the levee built from bottom sediments is stable even at the height of 8.0 m, despite the boundary conditions on the upstream side.

The Legal Regulations on Dams Construction on International Rivers： The Compliance of the Nile Basin Upstream States of the Regulations

The process of constructing hydraulic projects on international rivers is governed by several legal regulations, among the most important of these regulations are： the Principle of no harm, and the Principle of Prior Notification, protection of the river＇s environment and the Principle of Settling the International Disputes via Peaceful Means, which is considered one of the most important principles called for by the UN Pact, as it provides for adopting the peaceful means by the member states of the organization to settle international disputes through peaceful means, in addition to an applied study on the Nile Basin＇s projects.

Field observation of total dissolved gas supersaturation of high-dams

One of the possible negative environmental effects of hydropower stations is the supersaturation of total dissolved gas (TDG) downstream of high-dams,which can lead to gas bubble disease or even death of fish. By taking the TDG as the main study object,the paper launched the TDG field observations on Zipingpu,Three Gorges,Ertan,Manwan,Dachaoshan,Gongzui and Ertan dams in China. The factors affecting TDG generation and dissipation were explored. Energy dissipation structures,spill rates and operation patterns were the main factors causing TDG supersaturation. TDG saturations are essentially the same in the hydro-electric tail water and in the upper reaches,so hydro-electric tail water can be less TDG supersaturated through mixing downstream. The main factors affecting the dissipation process of the supersaturated TDG were tributary convergence,water depth and turbulence. TDG supersaturation was unevenly distributed in both the vertical and transverse directions. This study is important because it adds to the accumulating experience of TDG field observations of dam projects in China,and because it objectively and impartially evaluates the impacts of supersaturated TDG. The study also provides field data and references for future studies of TDG supersaturation caused by high-dams.