Himalayan Glaciers Climate Change, Water Resources, and Water Security (2012) / Chapter Skim
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3 Human Geographyand Water Resources
3 Human Geographyand Water Resources
Pages 49-72
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From page 49... ...
measuring and managing water scarcity. population data to estimate populations at risk, relying on the former when estimating urban populations1 and POPULATION DISTRIBUTION the latter when estimating population distribution per se.
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From page 50... ...
TABLE 3.1 Shares of National Populations Living in 600 million people in the Ganges/Brahmaputra Basin Hindu-Kush Himalayan Region Water Basins live at elevations below 1,000 m.2 Most of those living National below 1,000-m elevation are in India (79 percent) and Population Bangladesh (18 percent; Table 3.3)
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From page 51... ...
Wealthier gions dependent on the water resources of the Indus and Ganges/ Brahmaputra deltas, is the number of extremely large cities, or the and more urban populations, for example, have differphenomenon of urban "giganticism" (Preston, 1979)
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From page 52... ...
Rural dwellers tend to be poorer than their urban New migrants often do not have access to land, houscounterparts, but there is also substantial urban poverty ing, safe water and sanitation, or public services (e.g., and slum-dwelling in this region. Water supply and schooling or health care)
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From page 53... ...
are used for agricultural wastes, water quality can become the limiting factor for production in the HKH region. If agricultural devel- water availability -- in some parts of the HKH region, opment replaces natural land cover with crops with a pollution may reduce overall water availability.
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From page 54... ...
Total water withdrawals were 0.34 billion m3 yr-1 in 2009, or around 470 m3 person-1 yr-1. In general, the Committee found water use is As a downstream nation, Bangladesh has greater greater relative to natural runoff in the Indus Basin than reliance on external water supplies relative to water in the Ganges/Brahmaputra Basin, consistent with withdrawals (Figure 3.2)
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From page 55... ...
Nevertheless, China is the upstream Pakistan's internal water supplies are very limited nation on major watersheds of the HKH region; the relative to water withdrawals, on a per-capita basis Tibetan Plateau encompasses the origins of the Ganges (Figure 3.2)
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From page 56... ...
According to the Global Map of Irrigated Area plans to divert some regional water resources from the (Siebert et al., 2007) , which is nominally for around the south to its northern regions will also play a role in year 2000, irrigation is widespread in the Indus Basin, future regional water politics (Turner, 2011)
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From page 57... ...
Compared with the other basins has resulted in intense pressure to farm arable land in the study area, a relatively large amount of irrigated as extensively and intensively as possible. In India, water consumption in the Indus Basin is for cotton pro- this has caused a transition away from the established duction, along with rice, sugarcane, and wheat.
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From page 58... ...
A relatively large amount of irrigated water consumption in the Indus Basin is for cotton production. In the Brahmaputra Basin, by comparison, irrigation water use is dominated by rice production, while in the Ganges Basin, irrigated water is used primarily for wheat production.
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From page 59... ...
The GRUMP database headwaters of the basin. Aquastat data estimate 2.5 bil- shows 34.3 million urban dwellers in the Indus Basin, lion m3 yr-1 of withdrawals for municipal purposes in which with the above use rate would imply 5.3 billion Pakistan in 1991, rising to 9.7 billion m3 yr-1 in 2009, m3 yr-1 of municipal withdrawals in the Indus Basin in or from around 20 m3 person-1 yr-1 in 1992 to 54 m3 2000.
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From page 60... ...
Bhutan's total It is also true because dams are rarely built to satisfy a municipal withdrawals in 2008 was 0.017 billion m3 single purpose and the allocation of reservoir outflows yr-1 are all from the Brahmaputra Basin. needs to be balanced over time and between purposes The other major sector making water withdrawals depending upon available storage.
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From page 61... ...
alone would increase physical water scarcity without Generally, much of the focus is on water use by India, changes in human water-use practices. For instance, Pakistan, and Bangladesh, because Bhutan and Nepal in India one estimate is that by 2050 Indian demands have relatively small water withdrawals.
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From page 62... ...
Over the same time period, India's irrigation 2011) statistics show that between 1990 and 2008, area rate has increased by around 2 percent annually, from equipped for irrigation in Pakistan increased by 1.3 1995 to 2008, Bangladesh's irrigated area, which is in percent annually, up to 20 million ha, the vast majority both the Ganges and Brahmaputra basins, increased by of which is in the Indus Basin.
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From page 63... ...
by 2050. Assuming the urban use rate of water yr-1, such a scenario would increase agricultural water stays the same, expected population growth implies an withdrawals in the Ganges/Brahmaputra from 260 bil- increase in municipal water use to 13 billion m3 yr-1 of lion m3 yr-1 in 2000 to 400 billion m3 yr-1 in 2030 and municipal withdrawals in the Indus Basin in 2030 and nearly 500 billion m3 yr-1 in 2050.
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From page 64... ...
By this metric, and As discussed in Chapter 3, we primarily pre sent ignoring potential changes to water availability, the simple metrics of physical water scarcity. This approach Indus Basin seems the most likely of any of the study is driven by the limited data available for more sophisti- area basins to face problems of water scarcity (Figure cated measures that take into account, for example, eco- 3.6)
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From page 65... ...
The Brahmaputra has very little water scarcity, except in February and March, although water consumption still does not exceed natural runoff during those months. The large spike in natural runoff in the period June to September corresponds to the monsoon period.
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From page 66... ...
This societal capac MEASURING WATER SCARCITY ity, often called vulnerability or resilience, depends on conditions that promote human well-being generally. With the preceding analysis in mind, it is not surThe water-related aspects commonly measured include prising that there are many different ways to measure water availability or scarcity (discussed in the next sec- water scarcity.
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From page 67... ...
the Brahmaputra basin, on a monthly time step. This The costs of groundwater extraction include the costs of river has very little water scarcity, except in February needed energy and those costs are highly sensitive to the depths and March, and even then, water consumption does not from which the groundwater must be pumped.
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From page 68... ...
Water consumption does not exceed natural runoff in any month for the Indus. SOURCE: Based on data from Hoekstra and Mekonnen (2011)
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From page 69... ...
preparedness. Bangladesh has joint concerns about the coastal Comparative international water resources analysis hazards of climate change, inflows from major internais also advancing through the work of the South Asia tional rivers and tributaries, and domestic hydroclimate Water Initiative which convenes countries in the region risks.
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From page 70... ...
ning after a prolonged interruption. Water policy is The largest cities in South Asia are developing climate addressed in the Ministry of Agriculture, Irrigation, adaptation plans that include water systems, but the and Land, which raises an interesting point of compari- rapidly growing proportion of secondary and tertiary son across countries where water and climate policies cities show limited evidence, capacity, or higher-level are variously situated in ministries of agriculture, water support for addressing hydroclimate effects on water resources, and environment.
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From page 71... ...
crude estimates of water supply, demand, and scarcity. · Water use has been increasing over time in both Increasing the detail, consistency, and accessibility of the Indus and Ganges/Brahmaputra basins, and this water-use data (along with streamflow and aquifer data trend will continue for the next several decades, with as discussed in Chapter 2)
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