Hydraulic Structures: Fourth Edition

(Amelia) #1

The discussion of such an extensive and varied range of issues goes well
beyond the scope of this textbook. Some general reference to selected
issues is, however, dispersed through the text, e.g. Section 4.5 on sedimen-
tation, or Section 9.1.7 on the effects of river barrages on water quality.
The broader issues are examined and discussed within Golzé (1977),
in ICOLD (1988, 1992, 1994) and in specialist texts. Hendry (1994) exam-
ines legislative issues in the European context. The paper discusses the
role of environmental assessment in terms of the appropriate European
Directive (CEC, 1985), and discusses the provisions of the latter in rela-
tion to relevant UK provisions, e.g. DoE (1989). General questions of
environmental evaluation, impact assessment and benefit appraisal are
addressed in Clifton (2000), Thomas, Kemm and McMullan (2000), and
in Gosschalk and Rao (2000). The latter reference includes a concise
summary of the issues arising on three major high-profile dam projects, i.e.
Aswan High (Lake Nasser, Egypt) completed in 1968, and projects cur-
rently completing at Sardar Sarovar (Narmada River, India) and Three
Gorges (Yangtze River, China). The scale, and thus the overall impact, of
the latter two multi-purpose projects is of particular note.
Sardar Sarovar, the principal component of the inter-state Narmada
River development, is intended to irrigate some 1.9 million ha of land in
the states of Gujarat and Rajasthan and provide 2450 MW of hydro-
electric generating capacity. The concrete gravity dam is intended to reach
a height of 138 m, and has a designed overflow capacity of 79 103 m^3 /s.
Construction commenced in the late 1980s, but opposition in the courts
centred upon the displacement of an estimated 300 000 people from the
very many village communities scheduled for inundation has delayed com-
pletion of the dam beyond an interim height of 110 m.
The Three Gorges project centres upon a 2331 m long and 184 m high
concrete gravity dam impounding the Yangtze River. Design discharge
capacity of the overflow system is 110 103 m^3 /s. The immediate benefits
associated with Three Gorges on project completion in 2008/2009 will be
the availability of up to 22 109 m^3 of storage capacity for flood control on
the notoriously difficult Yangtze and 18 200 MW of hydro-electric generat-
ing capacity from 26 turbines (see also Section 12.2). Three Gorges is also
central to future development along some 600 km length of the upper
Yangtze, the lock system which bypasses the dam (see also Sections 11.8.3
and 11.10) providing direct access to the heart of China for ships of up to
10 000 tonnes. The project has engendered considerable controversy
however, since creation of the reservoir is estimated to displace at least 1.3
million people and submerge some 1300 known archaeological sites.
Overall cost is officially stated as $14 billion, but it has been suggested that
the true final figure will be considerably higher, with the most extreme
estimates ranging up to $90–100 billion. An outline perspective on Three
Gorges which makes plain the enormous scale and societal/environmental
impact of this regional development project is presented in Freer (2000).


INTRODUCTORY PERSPECTIVES 11

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