Friday, January 13, 2012

Two articles on the Yangtze River: diversions and climate change impacts

[Two articles on the Yangtze River, one on massive diversion project
known as the South-North Transfer project, and one from Nature on the
thawing permafrost at the mouth of the Yangtze and its implications for
river runoff.]

China to divert flows of its rivers
Moscow Time
12 January 2012

This year, China will spend over 10 billion U.S. dollars to divert the
flows of its rivers in the direction of the arid areas in its north.
This was announced by E Jingping, head of the South-to-North Water
Diversion Project commissioned by the State Council. It must be said in
the past few years that China has spent about 22 billion U.S. dollars on
this project, which has been compared to the Great Wall of China in

Late Chairman Mao Zedong first put forward the idea of the river
diversion project in 1951. At the time, he said that there was ample
water in the south but little in the north. It would be helpful if the
south lent some water to the north. The Water Resources Ministry took
the Chinese leader's idea as a guideline for action and embarked on a
plan to implement it. However, some time later, the Chinese leaders
shifted priorities to other projects. As a result, the process dragged
on for years. Only in 2002, after years-long droughts, the plan was
adopted. It provided for the construction of canals running along
Western, Central and Eastern routes.

As the year 2010 approached, it became clear that the project was far
from completion. The Central route which will be completed in 2014,
while the Eastern route in 2013. The work on the Western route which
involves building massive dams and tunnels has not started yet.
South-East Asian countries flatly oppose the diversion of the water from
the River Mekong, whose headstreams are located in China. The reason the
project has been put on hold is the delay in resettling 330,000 people
who live along the Central route.

"Any plan that interferes with the nature is dangerous from
environmental point of view," says head of the Yabloko Party's Greens
faction Alexei Yablokov, a Corresponding Member of the Russian Academy
of Sciences. "These plans might be effective for some time but will
produce unfavourable consequences in 20-40 years. The government will in
fact have to spend much more cash than what the project will yield the
first few years after the implementation," Alexei Yablokov said.

The head of the "Greenpeace Russia's" energy programme Vladimir Chuprov,
on his part, recalled that there was a similar project in the Soviet
Union. It was designed to fill the Aral Sea and irrigate Central Asia by
diverting water from Siberian rivers. It was not implemented because the
country broke up.

"It's very unfortunate that dozens of billions of dollars are being
spent on outdated technology, and this doesn't make sense," says
Vladimir Chuprov. "New technology would make it possible to implement
this task at a lower cost. Israel does not build canals worth billions
of dollars but water is brought directly to its plants. The U.S. is
doing the same in Arizona. China should make use of new technologies
rather than needlessly waste huge sums of money," he added.

According to Vladimir Chuprov, blocking the River Amur to build a
hydropower station would also be dangerous. Because of China's usage of
water taken from the River Argun, the border tributary of the River
Amur, the water level in the Argun River basin has fallen sharply. As a
result, the Zabaikalsky district is drying up, and the Dauria reserve is
on the brink of an environmental disaster. The common usage of water
resources in border regions should be approved by an international
commission, says the ecologist.

China's Water Resources Ministry insists that at present, 700 million
people in the country drink polluted water, and this has triggered
unrest in rural areas. After the planned diversion of water, this
problem is expected to be solved. The scale of environmental damage that
could incur is well known but this is a question of survival for a lot
of people, says the Ministry.

Meanwhile, Chinese ecologists say that large projects of this kind are a
niche for corruption. They regret the fate of the River Yangtze, which,
according to their forecasts, will dry up in 30 years.


Thawing permafrost reduces river runoff
China's Yangtze River is receiving less water as climate warms.
By Jane Qiu
6 January 2012

Chinese researchers have revealed that the amount of water entering the
Yangtze River near its source on the Tibetan plateau has fallen by 15%
over the past four decades, despite a 15% increase in glacial melt and
increased rainfall over the same period.

Wang Genxu, an ecologist at the Chengdu-based Institute of Mountain
Hazards and Environment, part of the Chinese Academy of Sciences (CAS),
says that the findings came as a surprise. "It is in contrast to results
from the Arctic where global warming has generally caused increased
river discharge," he says.

The source of the Yangtze River, on the Tibetan plateau, has been taking
in less water despite melting glaciers and increased precipitation.

Wang and his collaborators at the Cold and Arid Regions Environment and
Engineering Research Institute (CAREERI) in Lanzhou, also part of the
CAS, have just completed a five-year project to document changes in
glaciers, snow and permafrost and to assess their impact on water
resources in western China.

Ding Yongjiang, CAREERI's deputy director, notes that by contrast, many
other river systems in western China have seen more water input as
glacial retreat and rainfall have increased with a warming climate. The
runoff into the Tarim River headwaters, for instance, has increased by
13% since 1961, mainly as a result of increased glacial melt, which has
risen by 26%. "But the Yangtze headwaters are an exception," says Ding.

So why is the Yangtze different?

Permafrost puzzle

The decrease in runoff into the Yangtze is accompanied by widespread
changes in permafrost, says Wang. Across the Tibetan plateau, 10% of the
permafrost has degraded in the past decade. The area of alpine wetland
and high-vegetation-cover alpine meadow has decreased by 37% and 16%,
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This prompted Wang and his colleagues to assess whether these changes
had affected the amount of water running off the land. At a research
station near Fenghuoshan Mountain in the northeast of the Tibetan
plateau, they studied how the runoff from permafrost into the Zuomaokong
River, a Yangtze tributary, is affected by air and soil temperatures,
the depth to which permafrost has thawed and the levels of vegetation cover.

The researchers found that the depth of the 'active' ground layer � the
part that freezes and thaws every year � is crucial for water passage.
Runoff increased if the thawing layer was less than 60 centimetres deep,
but decreased if the thaw went deeper. The reasons are unclear but the
researchers suspect that when more of the permafrost thaws, the
thickened active layer may act like a sponge, soaking up water that
would otherwise have run off into the river. Alternatively, more water
may leak deep into the ground, also reducing surface discharge.

The thickness of the active layer is dictated both by air temperature
and vegetation cover, especially during thawing seasons. The researchers
found that nearly twice as much heat gets into severely degraded
permafrost alpine meadow compared with healthy meadows. "So the soil is
easier to thaw and more difficult to freeze, thereby deepening the
active layer," says Wang.

Wetland degradation may be even a bigger killer of headwater discharge,
says Wang. Runoff from moderately degraded wetland was up to 40% less
than in healthy wetland.
Warm response

Wang stresses that it is still early days for this research into what is
a complicated issue, but says that "the hydrology of the Tibetan plateau
seems to be responding to a warming climate differently from the
Arctic". In central Alaska, for instance, permafrost degradation has
resulted in the expansion of wetlands, whereas on the Tibetan plateau,
it has caused the land to become drier and more prone to desertification.

Shemin Ge, a hydrogeologist at the University of Colorado in Boulder,
says that the work "highlights the complexity of permafrost hydrology
and the importance of permafrost as a headwater source".

Until recently, the role of permafrost in water resources was largely
neglected, with glaciers hogging the spotlight. "Glaciers are
spectacular and get a lot of attention, whereas permafrost is humble and
less visible," says Ge.

But permafrost constitutes up to a quarter of Earth's land surface. "It
could be just as important [as glaciers] in terms of water resources,
especially in places like the Tibetan plateau where you have a lot of it."

A better understanding of the various components of runoff processes
will help to develop permafrost hydrological models, says Wang. Such
models could then be combined with other parts of the water cycle, such
as atmospheric circulation, to predict changes in water resources.

"Being able to make accurate projections is crucial for informing
polices and mitigation measures," says Wang.

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