Wednesday, June 15, 2011

HSR subsiding?

Areas of land subsidence in Taiwan; all except Taipei are fish farming centers (source). 

The new head of the public construction commission is all over the subsidence problem in central Taiwan, saying that it will cause the HSR to slow to a crawl within a decade if something is not done (AFP report). The Taipei Times gives more detail:
The earth is sinking under the nation’s high-speed rail line, New Public Construction Commission (PCC) Minister Lee Hong-yuan (李鴻源) said yesterday, warning that it could become inoperable in 10 years if nothing is done.

The soil has subsided because of excessive draining of ground water on a stretch of the line in Yunlin County and the limit of what is considered safe is fast approaching, Lee said.
“The high-speed rail can safely operate for a maximum of 10 years if the problem is kept under control,” Lee said.

“However, the area affected has expanded this year because of the water shortage problem. With more ground water being lost, 10 years has become a conservative estimate,” added Lee, who on Monday traveled to Yunlin with other government officials to inspect the high-speed rail line.
The Minister pointed out that the problem is serious not only in Yunlin but also in Changhua and Chiayi, threatening a total of 1,400 km2 in the three counties (this paper says "The total cumulative subsided land area in Taiwan has reached 1,941 km2 (Chang 2004), or about 20.5% of the total plains area of 9489.90 km2 (EPA 2007)"). I wrote an extensive piece on subsidence in Yunlin a while back, which gives some (scary!) numbers but also notes that the issue is compounded by the fact that laws are promulgated by the central gov't but enforcement is up to the local government, which often turns a blind eye to the problem. The paper cited above also notes:
Even if the area of continuous coastal subsidence is reduced, the cumulative subsided depth will still increase. In areas where fish farms are concentrated, such as Jiadung District of Pingtung County, in the beginning of the LSPTIP in 1995, the subsidence depth was 2.82 m but had increased to 3.24 m by 2006; the maximum cumulative subsidence depth on the coast of Changhua County in 2001 was 2.02 m, and that in Yunlin County was 2.10 m. However, by 2008, cumulative subsidence in these two areas had increased to 2.52 and 2.4 m, respectively (Water Resources Management and Policy Research Center 2009).
The original layout of the HSR line didn't help either; with unerring accuracy it was planned for lowlands with some of the worst subsidence on the island. Yet even as early as the late 1980s/early 1990s the subsidence problem in these areas was already known (for example) and could have been avoided by re-routing the line. Argh.
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Okami said...

Has a pool started yet for when the first train goes off the tracks?

Anonymous said...

I know one of the engineers who planned the HSR route. He said at the time that this would be a problem and that if I wanted to use the HSR I should do so during its first few years of operation. He said that everyone knew that this would happen.

I asked him at the time why it was being built like this if they knew there would be a problem. He said it was simply quicker and cheaper this way and no-one could really question the boss.