Yunlin County, located at southwest Taiwan, is one of the major agricultural regions of thecountry. With 48 percent of population in Yunlin engaged in agriculture, its agricultural productsmake up 15 percent of the total agricultural product value in Taiwan. As the government pursuedthe economic growth, the development of the offshore petrochemical industry park since 2001has been accompanied with environmental confl icts. One is the competition for water betweenindustry and agriculture, resulting from uneven rainfall distribution. The intense precipitationconcentrated over June to September when 80 per cent of the annual rainfall of 1627 mmoccurs, causes serious fl oods and also problems of water storage. The lack of water resourceleads the excessive extraction of groundwater by agriculture and the fi sh farming industry andresults in serious land subsidence in coastal Yunlin. Maximum rates of subsidence approach14.3 cm per year and total subsidence during the last two decades was as great as 1 meter.The land subsidence has complicated the fl ooding problems and further endangered theinfrastructure safety of Taiwan High Speed Rail. As a result, Taiwan government has allocatedabout $NT 116 billion since 2005 for 8 years for higher fl ood protection level to help ease thelowland inundation problems. In Yunlin, the strategies include regulation of 27 drainages/rivers, installation of pumping stations, and such. On the other hand, the construction of Hu-Shan reservoir and a proposed Concrete Solution and Action Plan for Subsidence in the Yunlinand Changhua Area in 2011 both aim to lessen the subsiding issue. The lowland managementand the spatial planning of this area have to be made with the utmost care, possibly with theaid of numerical predictions of the land subsidence and the fl ood risk analysis. Based onthe proposed above-mentioned policy and considering the potential impact due to climatechange, we predicted the possible consequence of annual land subsidence rates from 2012to 2038 with and without existing policy by using Land Subsidence Modeland and for threedesigned scenarios: Baseline, Do Nothing, and the Policy-implemented.
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