March 2016

It just doesn’t stop, and the scale of the damage to communities and the
environment is staggering.

NASA recently released the pair of images,
above, showing changes to the sediment system of Poyang Lake and its rivers.
The lake, these days much diminished in size, was once the largest freshwater
lake in China, its water feeding into the Yangtze and providing an important
haven for migrating birds. But when, in 2000, China shut down sand mining
along the middle and lower Yangtze, the activity, legal and illegal, simply
moved to Ponyang. The image on the left was acquired in 1995, the one on the
right in 2013. The scale of devastation is obvious - try the “image
comparison” feature for drama.

The text accompanying the images describes the problem here (and elsewhere) in
depressing detail:

When you see the vast expanses of > sand
in the Sahara and other major deserts, it is hard to comprehend how sand
could ever be a resource in short supply. Yet for certain types, the supply
of sand [is indeed > short.](http://mentalfloss.com/uk/geography/30414/were-
running-out-of-sand)

For the construction industry, river and lake sand is more desirable than
desert and ocean sand. To produce mortar for cement, concrete, and other
building materials, the angular sand particles found in rivers and lakes are
most useful. Making a strong mortar with the particles found in
deserts—which are rounded by winds—is more challenging because the sand does
not bind together as well. Likewise, ocean sand is mixed with salt, which
can cause metals to corrode. Washing this marine sand can be time-consuming
and expensive.

Over the past few decades, the global demand for construction sand has
boomed, especially in Asia due to
rapidurbanization.
In China alone, the demand for cement has increased 438 percent over the
past two
decades,according
to the United Nations Environmental Program.

In 2000, dredging and other sand mining become so intensive along the
Yangtze River that Chinese authoritiesbanned the > activity
along the lower and middle reaches of the river. This drove many sand mining
operators to Poyang Lake, a large body of water that flows into the Yangtze
about 600 kilometers (400 miles) upstream
ofShanghai.

This pair of false- > color
images captured by Landsat satellites shows the impact of sand mining on the
northern reaches of Poyang Lake. The top image was acquired by the Thematic > Mapper
on Landsat 5 on December 7, 1995; the second image shows the same area as
observed by Landsat 8’s Operational Land > Imager
on December 24, 2013. Water levels vary throughout the year at Poyang Lake,
with the lowest levels occurring in winter.

By contrasting the two images, we can see dramatic changes in the outlet
channel that connects Poyang Lake to the Yangtze river. Sand removal and
dredging have deepened and widened the channel significantly. These
activities also have left the remaining sandbars and shores with an
irregular, serrated appearance. Turn on the comparison tool to see the
changes.

As part of an effort to assess the scale of the sand mining and its
environmental impacts, a group of researchers analyzed data collected by the
Advanced Spaceborne Thermal Emission and Reflection > Radiometer
(ASTER) sensor on NASA’s
Terra
satellite. Using infrared data collected by ASTER in 2005, the researchers > found
that the lake was producing up to 236 million cubic meters of sand per
year—about 9 percent of the total produced by China. The researchers
estimated that the volume of sand removed was probably enough to make Poyang
Lake the largest sand mining operation in the world.

“Sand mining has compromised the ecological integrity of the lake by
contributing to less predictable seasonal water fluctuations and to a series
of recent low water events,” said [James > Burnham](http://silvis.forest.wisc.edu/people/james-
burnham), an ecologist with the University of Wisconsin and the
International Crane Foundation. Burnhan has conducted field research on
wintering waterbirds at Poyang Lake. “This is a lake that hosts 98 percent
of the endangered Siberian > Cranes
and Oriental White Storks, as well as a significant number of over a dozen
other endangered waterbirds in the winter.”

Google “sand” and news and, among the entertaining images of sand sculptures
and odd reports such as the discovery of hundreds of kilos of marijuana buried
in the dunes of South Padre Island, Texas, you will find, every day, endless
reports of the issues of sand mining around the world. A sampling:

[Vietnam](http://tuoitrenews.vn/society/33976/sand-
mining-meets-with-public-outrage-in-vietnams-mekong-delta),
[Nepal](http://kathmandupost.ekantipur.com/news/2016-03-28/locals-
protest-extraction-of-sand-and-aggregates.html),
[India](http://timesofindia.indiatimes.com/city/ranchi/Sand-
mining-rampant-in-Dumka/articleshow/51266474.cms) (endless problems, mafias,
crime), [Cambodia, Singapore and Malaysia](http://www.smh.com.au/world/sand-
wars-singapores-growth-comes-at-the-environmental-expense-of-its-
neighbours-20160225-gn3uum.html), the list goes on. The issues raised by the
documentary, Sand Wars ,
have also been taken up by _[The Smithsonian](http://www.smithsonianmag.com/smart-
news/demand-sand-so-high-there-are-illegal-sand-mining-
operations-180955669/?no-ist), the United Nations,
[Wired](http://www.wired.com/2015/03/illegal-
sand-mining/), _and [Coastal Care](http://coastalcare.org/sections/inform/sand-
mining/). Numerous TV and radio programmes have covered the topic. And yet so
few people are aware of it, and it just goes on and on.

Originally published at: https://throughthesandglass.typepad.com/through_the_sandglass/2016/03/index.html