Sat, Sep 18, 2010 page8

• Watery issues overflow in Yunlin

  • By Wen Jet-chau 溫志超
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  The problem of land subsidence in Yunlin County has recently come to the public’s attention, and there has been much discussion about how to tackle the problem. I have been doing research on land subsidence prevention and repair in Yunlin County for many years, and I would like to present a few ideas I have put together after eliciting opinions, for and against, from other people interested in this issue.

  I propose three main points for discussion with regard to Yunlin’s land subsidence problem. First, the demand for water resources in Yunlin County seriously outweighs the supply. As the shortage continues to worsen, the problem of excessive extraction of underground water refuses to go away. Second, industrial development keeps taking water from other users, causing farmers and fish farmers to bore their own wells to draw groundwater. Third, there is a question of whether we need a policy that would enforce the sealing off of wells.

  On the first point, the imbalance between supply and demand of water resources in Yunlin County is a longstanding problem. Yunlin’s water resources rely largely on surface water from the Jhuoshui River (濁水溪). Taiwan’s hydrology is characterized by rainy and dry seasons, and a plentiful supply of water is generally only available in the rainy season. In the dry season, there is hardly any water available at all.

  Agriculture has historically been the mainstay of Yunlin County’s economy. The shortage of water in the dry season means the agricultural water supply system managed by the Yunlin Irrigation Association can only provide water for irrigation in the rainy season, which coincides with the second rice crop from June to October. For that reason, the irrigation system on farms in Yunlin County generally allows fields to produce one rice crop every two or three years, or two crops every three years, with rice crops planted in the rainy season only. Rice is rotated in the fields with non-paddy crops that need less water, such as sugarcane.

  Under this irrigation system, there are two crop periods each year. Considering the available water resources, rice cultivation in Yunlin County should be confined to the second crop. Since that crop coincides with the rainy season, there should be no water shortage. Why, then, do we still have this problem of excessive groundwater extraction? The trouble is that, in order to make more money, farmers plant rice in the first crop period, from February to June. Since there is no surface water available at that time, the only way farmers can irrigate their paddy fields is by using groundwater drawn from wells that they bore themselves.

  This problem has been around for a long time, and it can only be completely remedied by adjusting agricultural policies and then ensuring that they are carried out. To put it simply, farm production which consumes a lot of water should not be practiced at times of the year when no surface water is available.

  Regarding the second point, industrial development is an inevitable aspect of urban progress. As far as I know, water transferred from agricultural uses to supply the sixth naphtha cracker petrochemical complex in Yunlin County has been made available from water saved through improved irrigation management. Water can only be diverted for industrial use on condition that farmers’ water needs under the existing irrigation system can still be satisfied. If this principle is adhered to, the order of precedence of access to water laid out in the Irrigation Act (水利法) will not have been affected, and industry cannot be said to be taking water away from agriculture.

  Turning to the third point, there are more than 100,000 wells in Yunlin County, more than 90 percent of which were dug without confirming water rights or applying for permission to build hydraulic facilities, as required by the Irrigation Act. If things were run in accordance with the law, the authorities would clamp down and stop illegal extraction of groundwater.

  The current reality, however, is that out of consideration for farmers’ livelihoods and to avoid clashes, illegal wells can only be dealt with when complementary measures are in place. Various water provision projects are under construction in Yunlin County. For example, the Hushan Reservoir (湖山水庫), once completed, will provide residents with 240,000 tonnes of water each day, and this should be sufficient to take the place of water that is currently drawn from underground.

  Land subsidence in Yunlin County has been going on for a long time, and the reason why it has continued to get worse is that those in authority have failed to face up to the problem and take the measures necessary to stop excessive extraction of underground water. Although pushing forward with a policy of sealing off wells can be expected to provoke a backlash from those affected, it would also highlight the seriousness of this longstanding problem of excessive groundwater extraction in the county. By announcing such a policy and sticking to it, the authorities could show the public that the fact that people have been doing the wrong thing for a long time doesn’t make it right.

  To sum up, the only way to prevent further land subsidence in Yunlin County and reclaim land that has already sunk is to work toward more rational distribution and efficient use of the county’s water resources. Industries that use a lot of water need to be properly regulated, in practice as well as in words. In this way, a balance can gradually be found between availability and demand for water. This goal can only be achieved through the coordinated efforts of central and local governments. As long as national government and local authorities are working at cross purposes, politicians and bureaucrats may argue until they are blue in the face, but it won’t help solve this important environmental problem.

  Wen Jet-chau is a professor in the Department of Safety, Health and Environmental Engineering at the National Yunlin University of Science and Technology.

  TRANSLATED BY JULIAN CLEGG
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