11.2.3.2. Water Needs and Management Implications
At present, approximately 57% of total water withdrawal and 70% of water consumption
in the world occurs within the countries of Asia. Table
11-8 presents the dynamics of freshwater use in Asia over the sectors of
economic activities. As is evident from this table, agriculture (irrigation
in particular) accounts for 81% of total water withdrawal and 91% of water consumption
in Asia. The area of irrigated lands in Asia currently amounts to 175 Mha and
may increase to 230 Mha by 2025. As Table 11-7
implies, the two most populated regions of south and southeast Asia account
for about 68% of water withdrawal and about 69% of water consumption in Asia
(see Chapter 4). More than 75% of the total water available
in India currently is used for irrigation. As much as 20% is required to meet
domestic and municipal needs—leaving just 5% for industrial needs. The
only river in north India that has surplus water to meet future needs of the
country is the Brahmaputra. This river, however, is an international river;
other countries such as Bangladesh may not approve of building a dam across
some of its tributaries. In peninsular India, only the Mahanadi and Godavari
have surplus water, but conveying it to drought-prone areas of the south is
problematic. Many states in India need to adopt measures for restricting the
use of groundwater to prevent a water famine in the future. China's rapid economic
growth, industrialization, and urbanization—accompanied by inadequate infrastructure
investment and management capacity—have contributed to widespread problems
of water scarcity throughout the country. Of the 640 major cities in China,
more than 300 face water shortages; 100 face severe scarcities (UNDP, 1997).
Taking into account projected dynamics of economic development in the temperate,
tropical, and arid and semi-arid regions of Asia, combined with the climate
change-imposed effect on hydrological regimes, agriculture and the public water
supply would require priority attention in these regions to secure sustainable
development and avoid potential intersectoral and international water conflicts.
Radical changes in water management strategies and substantial investments will
be required in Asia to cope with water problems in the 21st century. Adaptation
measures will include legal, institutional, and technical initiatives such as
modifying existing and constructing new infrastructure (reservoirs, interbasin
water transfer schemes), introducing water-saving technologies, upgrading efficiency
of irrigation systems, enhancing wastewater recycling systems, introducing low
water-use crops, and implementing groundwater protection programs.
At least 14 major international river watersheds exist in Asia. An integrated
and decentralized system of restoration and conservation of the water cycle
in these drainage basins is vital to mitigate the negative consequences of natural
and externally imposed perturbations. Watershed management is challenging in
countries where the people-to-land ratio is high and policy and management are
inadequate, prompting use of even the most fragile and unsuitable areas in the
watersheds for residential, cultivation, and other intensive uses. This is particularly
true for countries such as Bangladesh, Nepal, the Philippines, Indonesia, and
Vietnam, where many watersheds suffer badly from deforestation, indiscriminate
land conversion, excessive soil erosion, declining land productivity, erratic
and unreliable surface and groundwater resources, and loss of biodiversity.
Many watersheds in Asia already are stressed by intensive use of the land and
other resources and by inhospitable climate (especially in arid and semi-arid
Asia), beyond their ability to adequately supply water, prevent floods, and
deliver other goods and services. In the absence of appropriate adaptation strategies,
these watersheds are highly vulnerable to climate change. Global climate change
also may have serious water management implications on the territory of boreal
Asia. Recent assessments (Izrael et al., 1997a; CAFW, 1998) for all major Siberian
rivers (Ob, Yenisei, Lena) with 42% of the total freshwater inflow to the Arctic
ocean show that the main water management problems by the year 2050 will be
a consequence of significant annual runoff increases (up to 20%) and difficulties
with seasonal inundation and flood control measures.
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