In the 1990s, faced with the worsening problem of land subsidence in coastal areas, the Cabinet drew up a Land Subsidence Prevention and Reclamation Plan (地層下陷防治執行方案), which went into effect in November 1995.
Unfortunately, the plan has only marginally slowed down the incidence of land subsidence. Since its launch, Dacheng Township in Changhua County has sunk 1.6m, while Taisi (台西) in Yunlin County, Dongshih (東石) in Chiayi County, Hunei (湖內) in Kaohsiung County and Jiadong (佳冬) in Pingtung County have sunk 30, 40, 62 and 38cm respectively. In addition, the area affected by subsidence has spread further inland.
Half the land in Yunlin County is affected by subsidence, which may pose a threat to rail traffic safety. In addition, floods brought by Typhoon Morakot last August badly hit low-lying areas of southern Taiwan.
Because the “prevention” part of the subsidence plan has not been very effective, the government has also had to spend a great deal of money on “reclamation,” but that has also had limited impact. The main reason for the plan’s ineffectiveness is that it attempts to reduce land subsidence by limiting land-based fish farming to five zones where there are a high concentration of fishponds and the land is already sinking, rather than trying to reduce the overall area of fishponds along the coast.
Coastal land subsidence has continued unabated because most fish species raised in coastal fish farms need more than 80 percent fresh water, which is drawn from underground.
The government’s subsidence prevention and reclamation plan does nothing to regulate agriculture, which is the biggest user of underground water, drawing twice as much as aquaculture. Regarding restrictions on the use of underground water by industry, which continues to increase its volume of water consumption and is gradually becoming another contributing factor to the land subsidence problem, the plan offers guidelines, but no means of practical enforcement.
The first thing the government needs to do as a matter of urgency is to accept the need to regulate and restrict the use of underground water by agriculture and industry. In addition, the water drawn by private wells is not included in the official figures, which therefore seriously underestimate the real level of underground water usage.
Another shortcoming of the plan is that, while it attempts to cut the area devoted to fish farming, it does not offer complementary measures to provide for the livelihood of those who want to quit the business. As a result, local governments have not been able to cooperate with the central authorities’ demands that wells be sealed and people be forced out of the fish-farming business.
Research carried out by myself and colleagues indicated that the main reason people engage in fish farming is to make a living. If appropriate subsidies and retraining were available, 66.1 percent of fish farmers would consider quitting. Research by others has produced similar results.
The government needs to establish a high-level inter-ministerial task force responsible specifically for cutting the area of land used for fish farming in sinking coastal areas, to reduce land subsidence.
In order to reduce the area used for fish farming, the authorities must come up with a plan to help people quit the business rather than trying to force them out. This should include regulations on providing subsidies, training in other skills, assistance in changing profession and help finding employment for those who quit fish farming. Owners of land originally used for fish farming should sign agreements to stop using their land for that purpose and to seal off their wells.
The government would have to subsidize the work of filling in fishponds and assist in turning the land to other uses. This approach would contrast starkly with the current policy of using punitive measures to stop fish farming without seeking to change the operational environment in which it takes place. Such an attitude is impractical because people will be lured back to fish farming when the price of fish goes up.
How much funding would be required?
According to data compiled by the Fisheries Agency, last year the fish farming industry employed 70,841 people. If 40,000 of them were to quit the business (with priority given to those working in sinking coastal areas), and if each person were paid an average subsidy of NT$25,000 per month for a period of 10 years, the total funding required would be NT$120 billion (US$3.8 billion).
There is also the matter of filling in fishponds, which could be done using sediment dredged from reservoirs and riverbeds and mud deposited by flooding. Fishponds are around 1.5m deep and the total area of fishponds in sinking coastal areas is 11,597 hectares. If 10,000 hectares of fishponds were filled in and the cost of filling in one hectare is NT$4 million, then the total cost would be NT$40 billion.
The total cost of job-change subsidies plus filling in fishponds for 10 years would come to NT$160 billion, or NT$16 billion per year. Such a plan would greatly reduce coastal subsidence and allow for the proper planning of future development in areas where the land has been sinking. It would also greatly reduce the social costs brought about by land subsidence.
Research indicates that the social costs of subsidence in four coastal townships between Pingtung County and Fangliao (枋寮) in Kaohsiung County alone are somewhere between NT$27 billion and NT$101.9 billion per annum, while Taiwan’s four-year budget for water control and flood prevention is over NT$300 billion. The NT$16 billion annual budget proposed here pales in comparison, but it would have a dramatic impact.
Although making big cuts in the number of coastal fishponds would quickly bring substantial results in alleviating coastal subsidence, this measure alone would not completely solve the problem. The proposed task force would also have to push for a plan that encouraged farmers to quit agriculture, thereby cutting the area given over to farming. A monitoring system would also have to be put in place to supervise the building of industrial facilities that use a lot of water. Fisheries, agriculture and industry woud all have to learn to use water more efficiently and this task force would help them do that.
Current policies intended to reduce land subsidence, such as setting up fish-farming zones, banning freshwater fish farming, encouraging seawater fish farming, temporary stoppages in fish farming and so on, have either produced unwanted side-effects or proved difficult to put into practice. The solution proposed here is that the government sets up a high-ranking task force that would approach the land subsidence problem from the point of view of farmers and aquaculture operators.
Policies related to aquaculture and fish farming, land subsidence prevention and related land conservation and restoration issues are need to be considered as key elements in a more integrated approach. If this task is not addressed, then land subsidence in coastal areas will continue to worsen and eventually lead to disasters even worse than the deadly floods brought by Morakot.
Peter Sun is an associate professor of aquaculture at National Pingtung University of Science and Technology.
TRANSLATED BY JULIAN CLEGG
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