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Future
management of water must continue to work towards
achieving a sustainable balance between water for
agriculture and water for natural ecosystems.There
is, therefore, a need to develop, test and apply best
practice frameworks that enable explicit inclusion
of the environment as a sector in basin water resources
development and management to avoid the often irreversible
and costly damage to the environment.The starting
point for the discussion is that all water in the
hydrological cycle has a value in terms of ecosystem
services; none of it flows to the sea wasted.All use
for human purposes is a trade-off between current
and future use.
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| ACTIONS
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| Securing
water for the needs of the environment
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Development and application of methodologies
to determine the water requirements of ecosystems,
or environmental flow requirements,must be followed
up by actions to secure these water requirements
through formal and informal mechanisms.
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Click
to enlarge
The map above shows
environmental water stress using the Water
Stress Indicator (WSI). The different
degrees of water stress are shown within
major river basins around the world
Source: IWMI |
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Sufficient water is required for wetlands to
maintain themselves and provide for the flora
and fauna dependant on them.
Photograph by IWMI |
| Enhancing
benefits in agriculture-wetlands interactions |
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Accounting for both livelihood and environmental
service benefits offers the opportunity to use
wetlands wisely. In Southern Africa, for example,
irrigated agriculture (in Malawi, Mozambique,Tanzania,
Zambia and Zimbabwe) is closely linked to the
development of small wetlands or dambos.While
to date agriculture has often completely replaced
the wetland ecosystem (through “land reclamation”),
opportunities exist to optimize two functions
jointly.
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Photograph by Matthew
McCartney, IWMI
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| Manage
agricultural water use sustainably: ignoring
environmental impacts can lead to
failed projects
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While all agricultural water use has positive
and negative environmental impacts, failure to
understand upstream soil erosion and resulting
reservoir siltation, or impacts of flow reduction
on downstream recession agriculture, or impacts
of environmental changes in waterborne diseases
such as schistosomiasis or malaria, has led to
failed projects.The good news is that well-managed
agricultural water use can offer major opportunities
to improve health and environmental values.
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Irrigated agriculture being undertaken through
the
development of dambos in Zambia.
Photograph by Mutsa Masiyandima, IWMI |
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In the upper photo farming
is taking place alongside a wetland in Ethiopia.
In the lower photo a lady in Ghana carries firewood
representing yet another use
of the environment.
Photograph by Sanjini de Silva, IWMI
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FACTS AND FIGURES
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Percentage
of rainfall consumed/used to support direct and
indirect human uses of water
System/use
Food - irrigation
Food - rainfed
Domestic & Industry
Instream ecology
Flood runoff
Permanent Grazing
Grasslands
Forests and woodlands
Arid lands
All others
Total
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% of rainfall
2
4
1
8
27
18
11
17
5
7
100 |
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DEBATES
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Ecosystems:
are they users or providers of water?
While some view ecosystems as providers
of water through wetlands and other ecosystem
services, others contend that ecosystems
do not provide water, they consume water,
just as much as agriculture does.. |
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Need
to balance water for ecosystems as their
services are in greater demand.
As income per capita goes up, as happened
in Asia,notably in China and India at
present, the demand for ecosystem services
such as clean air and recreational values,
goes up. |
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Ecosystems
provide valuable services that are the
foundation upon which human life is built. |
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Need
to consider the multifunctionality of
agricultural lands and include agricultural
lands in biodiversity conservation. |
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Irrigated
rice fields and irrigation channels are
classified as part of the human-made wetland
by the Ramsar Convention. In
this respect, the ecofriendly feature
of rice paddy fields with ponded water
has to be re-evaluated. In the Asia Monsoon
region,Water in paddy fields is not only
vital for food production, but also provides
a broad range of services related to ecosystems.
Thus paddy-systems can be defined as wetlands
which have good potential for maintaining
both human cultures and natural ecosystems
in a sustainable manner. |
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