Comments by "Peter Jacobsen" (@pjacobsen1000) on "PolyMatter"
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13:00 A little correction: It says Shanghai has subsided 2 meters in the last two decades. This is not correct. Land subsidence IS a problem in Shanghai, starting in the early 20th century, when Shanghai's industrialization began. It became most serious in the 50s and 60s and mitigation efforts began, primarily by pumping rainwater back into the ground and restricting use of ground water.
In the last two decades, Shanghai has seen average subsidence of 5.5 mm per year, or a total of 110 mm (appx. 4.3 inches).
Nowadays, we get most of our tap water from the Yangzi River. A large reservoir was built in the delta back in the 00s, if I remember correctly. The reservoir allows sediment to clear, after which water is pumped to treatment stations before being released into the pipes. Technically, Shanghai's tap water is drinkable, but partly due to old pipes, it doesn't taste very good, and most people buy drinking water in 4-gallon jugs and only use tap water for showering, tooth brushing, etc.
(I have lived in Shanghai since 1996, and while that in itself is not evidence of anything, I have followed local developments closely).
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