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inter-disciplinary nature of the process means that
'it falls between the cracks of different sectoral
agencies responsible for irrigation, agriculture and
conservation'.
Other case studies show far less success than
the example of Sukhomajri. The Lower Snake
River is a tributary of the Columbia River in
the north-western USA: plans to remove dams
in order to rehabilitate salmon and steelhead
populations have so far foundered in legal wrangles
between different interest groups (Rogers, 2009).
In the Yangtze River, China, the principles of
IWRM have been adopted at the legislative and
policy level, but with limited implementation
(Yang Xialiu and Muller, 2009; Bridgewater
et al
.,
this volume). The focus has been on massive
developments such as the Three Gorges Dam (Plate
2) and the proposed South to North water transfer
from the Danjiangkou Reservoir. There are now
some 44 000 impoundments in the basin, and
the extinction of the Yangtze River dolphin is a
sad reminder of the environmental costs of such
development.
Despite their optimism, the case studies described
by Lenton and Muller (2009) confirm that IWRM
successes are confined to small-scale catchments
such as the Sukhomajri project. Larger-scale case
studies, such as South Africa and the Mekong,
reveal excellent intentions, plans and policies, but
only partial implementation at best. For example,
in South Africa, much has been accomplished to
supply clean water and sanitation facilities, but
integrating the supply side with other social and
environmental issues has proceeded only slowly
and sporadically.
The application of IWRM has been criticized
(e.g. by Watson
et al
., 2007) who concluded that
there is 'very little agreement regarding what
[IWRM] means in practice', and by Biswas (2004,
2008) and Biswas and Tortajada (2004) who
argued that the implementation of IWRM has
never been assessed comprehensively, and that its
implementation has nowhere achieved more than
a third of its objectives. The reasons for this are
explained by Kerr (2007): 'Theories from commons
research predict great difficulties in managing
complex watersheds and explain why success
has been limited to isolated, actively facilitated
microwatershed projects with a focus on social
organisation'. The report of the Comprehensive
Assessment of Water Management in Agriculture
(2008) went further to say that 'The so-called
IWRM initiatives in developing country contexts
have proved to be ineffective at best and
counterproductive at worst'. So, it seems that
IWRM is an innovative and visionary framework to
aim at, but its implementation is too complex and
multivariate to be practical in most catchments, and
especially in large basins where water resources are
already allocated substantially.
The remainder of this chapter describes an aspect
of sustainable water resource management that has
become globally accepted in the past two decades -
environmental water allocation, or 'environmental
flows', as it is known for rivers. The maintenance
of adequate flows in rivers throughout different
seasons, and in the face of rising water demands,
is one of the major requirements for successful
river conservation. Cases of over-allocation and
abstraction from rivers have resulted in many
instances of dry river beds worldwide, even in
very large rivers such as the Yellow River in
China (Bridgewater
et al
., this volume) and the
Indus River in Pakistan (Khan and Akbar, this
volume). The main reason for the success of
environmental flows, in contrast to IWRM, is that
it is a clear process, with well developed and
described methodologies at different levels of detail,
and a well-defined end-point which is accessible
and amenable to policy-makers, managers and
engineers, as well as to scientists and nature
conservationists.
Environmental flows for rivers
Environmental flows can be described as 'The
quality, quantity and distribution of water required
to maintain the components, functions and
processes of aquatic ecosystems on which people
depend. The process of assessing an environmental
flow regime will require a societal judgement
about the state in which the ecosystem should be
maintained. The water required for any aquatic
ecosystem will depend on the environmental
objectives set for that system.'
