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Wang slams study

An Academia Sinica research report suggests that long-term excessive groundwater pumping in southern Taiwan might deplete certain aquifer layers, leaving no pumpable groundwater within five years. But the Water Resource Agency (WRA) yesterday said this pessimistic evaluation was based on outdated data and that constructive land-subsidence prevention measures had shown positive results.

Wang Chung-ho (汪中和), an Institute of Earth Sciences research fellow at Academia Sinica, recently reported on the nation's water resources, suggesting new technologies for rainwater harvesting as a possible solution to what he calls an emerging water crisis.

Wang and his research associates analyzed available statistics about the past century's rainfall, discovering that annual rainfall in southern Taiwan has decreased by 10 percent, or 60cm, since the 1940s.

In addition, Wang warned that excessive groundwater pumping in coastal areas in southern counties would soon deplete certain aquifer layers. In the report, Wang said that on average Taiwan each year pumps 2 to 3 billion tonnes more groundwater than is replenished.

However, WRA director-general Chen Shen-hsien (陳伸賢) told the Taipei Times yesterday that the possible dangers resulting from land subsidence had been mitigated. Since 1995, the agency and the Council of Agriculture have drafted the Land Subsidence Prevention and Reclamation Plan (LSPRP), which designated affected areas and promoted various strategies such as promoting water conservation, limiting well-drilling and exploring more sources of surface water as supply.

"In 2001, the amount of groundwater pumped was only 500 million tonnes more than was recharged underground," Chen said.

Statistically, the area of coastal areas affected by land subsidence is about 1,700km2, or about six times the area of Taipei City. The most serious situation is at the village of Wenfeng in Chiatung Township, Pingtung County. In the last 25 years, the ground there has dropped by 2.26m.

Chen stressed that land subsidence remains one of his agency's major focuses, and said that currently Changhua and Yunlin counties deserve more attention in regard to this problem. Next month, 15 townships in southern Taiwan will be further classified as affected areas, he said.

"Damaged areas can never be rehabilitated, but they might get worse if we don't do anything now," said Kao Ruey-chy (高瑞棋), LSPRP vice regiment commander.

Kao said that land subsidence had been significantly reduced due to educational efforts targeting aquaculture entrepreneurs. In Chiayi, one of the most affected counties, the ground sinks at a rate of less than 5cm a year, but in 1991, the rate was up to 21cm a year.

"Farmers now are encouraged to adopt innovative technologies to recycle wastewater not only in order to rely on groundwater less, but also to preserve the value of their land," Kao said.

Kao said such technologies became affordable for farmers because they had been developed to recycle industrial wastewater.

Between the mid-1970s and the early 1990s, the nation consumed 7 billion cubic meters of groundwater annually, but received an annual average rainfall of only 4 billion cubic meters.
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