Conservation

Stopping the Slides

• Byline:PAT GAO
• Publication Date:06/01/2002

In recent years, many parts of Taiwan have been hit by massive mudslides set off by typhoons. Among the causes are the 1999 earthquake and improper slopeland development. New laws and regulations are being put in place to bring the situation under control.

When typhoons Toraji and Nari ripped through Taiwan last year, almost 200 lives were lost. Many of the victims--along with their homes and often the roads leading to their homes--were buried by mudslides. Especially hard hit were Nantou County in the center of the island and Hualien County on the eastern coast.

Ever since a typhoon in July 1996 set off similar mudslides that devastated Shenmu Village in Nantou County, an incident covered intensively by the media, the word "mudslide" has become a trendy term in Taiwan, used to describe any kind of sinister and destructive force. Vice President Annette Lu, for example, earlier this year referred to a video sex scandal involving a female politician as emblematic of the society's "moral mudslide."

The problem of mudslides, landslips, and other types of slopeland erosion has become one of the most common kinds of natural catastrophes striking Taiwan. Considering Taiwan's specific geographical and climatic environment, it is not surprising that they should occur. Mountainous or hilly terrain occupies about three-fourths of the island's 36,000 square kilometers of land area. Running eastward or westward downhill from the Central Mountain Range that forms the spine of the island, most of the rivers are short and steep--and turn into torrents during rainstorms, carrying heavy loads of mud and silt. Moreover, the seasonal distribution of precipitation is uneven. Due to the "Plum Rain" in late spring and the typhoon season that lasts from summer to autumn, more than 70 percent of the annual average 2,510 millimeters of rainwater in the Taiwan area usually falls between May and October.

According to the government's Council of Agriculture (COA), slopelands are vulnerable to mudslides when they receive more than 40 millimeters of rainfall in an hour. In the case of Shenmu Village, the 1996 typhoon brought nearly 2,000 millimeters of rain overnight to the nearby Mount Ali (Alishan). To make matters worse, the powerful earthquake that struck Taiwan in September 1999, registering 7.3 on the Richter scale, aggravated the unstable topographical conditions in the area around its epicenter in Nantou. Immediately after the quake, a COA survey found that the number of rivers and streams susceptible to mudslides had risen from 485 to 722. A more thorough examination later conducted by the COA identified more than 1,500 rivers and creeks as subject to the threat of mudslides.

"We can't escape nature, and heavy rains, floods, and landslides are just part of nature," says Lee Yung-jaan, chairperson of the Green Citizens Action Alliance, an environmental group based in Taipei. "They become disastrous only when nature's ability to protect itself is weakened." Often it is the impact of human activity that creates or at least worsens the problem, notes Lin Meei-ling, a professor of civil engineering at National Taiwan University. She also heads the task force dealing with mudslides--the Debris Flow Group--at the National Science Council's Program for Hazard Mitigation. "With regard to a particular calamity, sometimes it's hard to determine to what extent environmental factors were to blame and to what extent human involvement," says Lin, "but surely human abuse exacerbates the situation." This liability is quite apparent in Taiwan, where the population density of about 610 persons per square kilometer makes it the second-most-crowded country in the world after Bangladesh. The population density is even higher on the plains, the areas most suited for habitation and farming, though they account for only one-fourth of the national territory. As a result, the use of slopeland for development--for housing construction or to grow fruit, tea, or betel nuts--has become inevitable.

Until the early 1970s, such development remained unregulated, since the scope of related laws was confined to urban areas. The Construction Law of 1973, however, introduced measures governing buildings outside of urban jurisdictions. Three years later, the Ministry of the Interior (MOI) instituted regulations managing the use of nonurban land. The rules called for assigning such areas to land-use categories such as agricultural, industrial, rural habitation, forest, slopeland, scenic spots, national parks, and "special use." In the same year, the Slopeland Conservation and Use Act was passed, defining "slopeland" as having either an elevation of more than 100 meters or a gradient of over 5 percent. The act specifies that slopeland should be subject to conservation measures by applying engineering, agronomic, or forestry techniques. In 1994, the Water and Soil Conservation Law was promulgated, granting authority to the COA and local governments to take action to prosecute any violators of the laws.

Although numerous relevant regulations are now in place, "more often than not, land development outpaces the authorities' ability to control it through planning and management," observes Lin Meei-ling. One noteworthy example concerns the Slopeland Development and Construction Management Measures adopted in 1983. Under this system, any construction plan must obtain approval from a regional planning council organized by the MOI or a local government. It must also undergo an environmental impact assessment. But many construction permits had already been issued before the new regulations be came effective, and those projects were exempted from the requirements. One of these was the Lincoln Mansions, a complex of five-story structures in Hsichih in Taipei County, which opened in 1993, built under the relatively loose pre-1983 rules. Part of it toppled during a 1997 typhoon, killing twenty-eight of the residents. Compared with the neighboring King Villas project that accommodated 690 households on a twenty-one-hectare piece of land in accordance with the new regulations. The Lincoln Mansions had squeezed nearly a thousand households onto merely five hectares.

"The Lincoln Mansions calamity came as a great shock to both government officials and the general public," says Lin Yi-hou, director-general of the MOI's Construction and Planning Administration (CPA). "Their previous notions about housing safety and slopeland management got radically altered." In the wake of the Lincoln Mansions tragedy, the CPA undertook a review of all projects licensed prior to 1983 but not yet constructed. It examined the plans for some 3,400 buildings, due to cover a total of 704 hectares of slopeland, with an eye to potential risks. The administration also established a monitoring system to watch the progress of such projects as well as to check the condition of existing slopeland dwellings. In 1998, it took the further step of reducing the maximum slope permissible for development from 40 percent to 30 percent, which some critics regard as an overly strict limitation. "It's quite reasonable to be more restrictive, at least for the time being," explains Lin Yi-hou. "We took into account the shortage of manpower in the local governments for inspection and supervision, questions about the level of the engineering personnel's technical skills, and our citizens' growing consciousness and concern about building safety."

Besides the construction industry, the agricultural sector has also come in for its share of blame for land erosion. In recent years mountain slopes have increasingly been used for the cultivation of such high-value plants as betel-nut trees, tea, and vegetables. But the shallow roots on these plants cannot anchor the soil the way forests can. "Take fruit-growing for example," says environmentalist Lee Yung-jaan, who also teaches at the Graduate Institute of Local Development and Management in Tainan's Leader University in southern Taiwan. "For the farmers, the bigger the fruit, the higher the profits. But water and soil conservation requires thick trunks, boughs, and foliage instead." Which objective should the plant breeding aim at? Tang Hsiao-yu, deputy director of the COA's Forestry Department, calls attention to another problem concerning hillside agriculture. "When roads are constructed in the mountains to facilitate harvesting," he says, "if the excavated earth and stone are not disposed of properly, the rainfall will wash it downhill, even into the dam if there is one."

As a major example of improper road construction, Yu Jung-sheng, director of the Geotechnical Engineers Association, cites the 74-kilometer New Central Cross-island Highway. "During its construction in the 1980s, when the relevant regulations weren't as strict as they are now," he notes, "the work crews dug into the mountains and just tossed the stone and earth into the valley, where it easily got mixed with rainwater to set off mudslides." The tourist facilities and farms that sprang up in the mountains after the highway was built also exacerbated the erosion problem. As a result, whenever typhoons or heavy rains cause damage in central Taiwan, it is usually the area along the highway that suffers the most.

The COA considers about 32,000 hectares of Taiwan's slopeland to be agriculturally overdeveloped. In January this year, it launched a project to resolve the problem by requiring those owning or renting the land to remove the excess plants or engage in reforestation before the end of 2007. That approach fits in with the government's ongoing plan to promote forestation as a means of preventing mudslides. By the end of 2004, it aims to have planted 10 million trees on 5,600 hectares of land that had been denuded by the 1999 earthquake and recent typhoons. This plan carries forward a similar five-year project that was started after the devastating 1996 typhoon and covered 32,091 hectares in various parts of the island.

While supporting these plans, Lee Yung-jaan notes that some farmers cut down grown trees and then reforest the land in order to qualify for subsidies from the government. "The result is even worse than doing nothing," he says, "for it may bring the removal of indigenous trees and the introduction of foreign species with unfortunate ecological side effects." The COA is aware of this kind of activity, says Tang Hsiao-yu. "We plan to increase the subsidy to encourage more forestation, and when we do that we'll also start to offer subsidies to owners of existing trees."

Another strategy being pursued by the COA is designed to help prevent the mudslides even more directly. "More than 90 percent of the mudslide cases can be traced to places where the mountain terrain collapsed, especially in the areas affected by the 1999 quake," says Wu Huei-long, director-general of the COA's Soil and Water Conservation Bureau. "So we decided to adopt 'eco-engineering' methods to restore the natural landscape." The ecological approach is characterized by minimal use of concrete structures, instead employing natural materials as much as possible and adopting designs that resemble what occurs in nature. The COA, for example, hired residents of communities in the quake areas to fill up the crevices in the mountain slopes with earth, thus preventing rainwater from entering the gaps and destabilizing the soil. This technique is being used on a trial basis, and will be supplemented by more traditional engineering methods if necessary, says geotechnical engineer Yu Jung-sheng.

A crucial element in the COA's eco-engineering projects is an emphasis on close coordination with the local communities. "People shouldn't expect that whatever repair work the government carries out will assure their security once and for all," advises Lin Meei-ling. "Recognizing the limitation to what engineering efforts can accomplish, those living in mountainous areas should cooperate with the government to take safety precautions--participating in drills, paying attention to alerts, and agreeing to evacuation if necessary." Her task force publishes annual reports rating the rivers threatened by mudslides and distributes the reports to relevant departments of the central and local governments. Lee Yung-jaan, who teaches courses on how communities should prepare to handle disasters, cautions that most people in Taiwan are not sufficiently attuned to dealing with the challenges posed by the environment. "They'll think about taking action only after a major catastrophe takes place," he says, "and even then the effort is just aimed at the short-term results."

For the various aspects of water and soil conservation to be attended to properly, the government needs to devise a long -range program for national land use, integrating relevant regulations on such topics as urban and rural development, protection of forests, and usage of slopeland. Such a program is now taking shape. In March of this year, the cabinet sent a new land development bill to the Legislative Yuan for deliberation. "This law will set guidelines for the use of various kinds of national land such as mountain slopes, seacoasts, farmland, offshore islands, and aboriginal reservations," explains the CPA's Lin Yi-hou. "It also aims to strengthen the requirement for prior approval before land development." Once the law is enacted--and if vigorous enforcement follows--the scourge of mudslides may at last be stemmed.

A Hard Nut to Crack

In the long history of Chinese medicine, betel nuts have been used to treat intestinal disorders and parasitic infections, but today few betel-palm growers intend to supply the medicinal market. An estimated three million people in Taiwan--a full 13 percent of the population--chew betel nut as a regular habit to produce a mild "high." This "green gold" accounts for more than NT$100 billion (US$2.86 billion) in annual sales--roughly 1 percent of gross national product. Some two million people rely on the business in whole or in part for their livelihood.

The "Taiwan chewing gum" has gained popularity since the 1970s, when the country needed large numbers of blue -collar workers for its new export-oriented, low-tech, labor-intensive industries. As betel-nut chewing stimulates blood circulation, it was favored by laborers as a source of increased stamina, and encouraged by foremen to boost productivity. The product gives its users a kick strong enough to create an addiction. While the pulpy nut itself is not detrimental to health, the additives--chiefly a lime paste--can cause oral cancer and mucous membrane fibrosis.

According to the government's Council of Agriculture, some 60,000 hectares of land are currently planted with betel palms, double the area of a decade ago. The increase represents a switch by farmers from such traditional commodities as rice and sugarcane, grown in large fields and requiring considerable manual labor, to low-maintenance, cash crops grown in small plots. A betel-nut grower just spreads some herbicide and fertilizer, and when the trees mature after about five years, he can enjoy a regular harvest twice a year for the next forty years. For Taiwan's aging agricultural workforce, the appeal of cultivating betel nuts is understandable.

Nonetheless, betel nuts are a controversial business. In addition to the health concerns, betel palms have been blamed for destabilizing the soil as they take the place of forests on mountain slopes--the location of more than one-sixth of the betel-nut cultivation. Unlike the trees they displaced, betel palms are less able to retain moisture and provide shade because of their shallow roots and few leaves. They consequently contribute heavily to soil erosion and lower the water table. The retail side of the business, featuring what have become known as "betel-nut beauties," is another source of controversy. The nuts are sold throughout the country at more than 100,000 roadside stands, most of them staffed by young girls clad in skimpy attire to attract the attention of customers--since nearly all betel-nut chewers are male.

In 1997, departing from its previous policy toward the betel-nut trade of "Three Noes"--no encouragement, no assistance, and no prohibition--the cabinet issued a set of Betel Nut Regulatory Measures. Under the new program, the government provides subsidies to growers who turn their plots back into forest. Still, the number of betel palms must be reduced gradually, for it is a matter of several million people's livelihood.