Running through Taiwan's most populous region, the Keelung River is one of the island's most important waterways but has frequently shown its capacity for destruction. What can be done to create a safe and pleasant environment for residents of the river basin?
Hsichih is an ordinary community on the outskirts of Taipei City--except when it rains heavily. In the past few years the name Hsichih has become almost synonymous with flooding--disasters often severe enough to paralyze the town, wreak extensive property damage, and take dozens of lives. A pair of typhoons in 1998, Zeb and Babs, each inundated some 6,000 households as water rose as high as five meters above the ground. Two years later, Typhoon Xangsane was even more catastrophic, affecting 10,000 households in Hsichih as water levels reached up to eight meters in some parts of the town. Thirty-one deaths were recorded throughout the Taipei area. But the worst came in September 2001 when Typhoon Nari victimized almost all the residents of Hsichih and left fifty-one people dead in Taipei City and County. (It also shut down major sections of the Taipei Mass Rapid Transit for weeks and caused NT$1.4 billion [US$41 million] in damage to the system.) "Each of these typhoons made us suffer from the disruption of water and electricity services for at least six days," recalls Angela Peng, who has lived in Hsichih for five years. "And when Nari hit, it brought a flood that could submerge a three-story building. My property damage came to about NT$100,000 (US$2,960), but that's nothing compared with what other people lost from the flood."
Much of the blame must go to the Keelung River, which runs through the town of more than 160,000 people. Originating in Taipei County's Pinghsi Township, the eighty-six-kilometer river meanders through Keelung City and the Taipei basin, finally merging with the Tamshui River at Kuandu, north of Taipei City. When a torrential rainstorm occurs, the river often overflows, flooding places along its banks such as Patu, Hsichih, and Nankang. According to the Tenth River Basin Management Bureau, the Taipei basin was still a lake until about three hundred years ago, which means it remains highly vulnerable to floods. The bureau, which comes under the Ministry of Economic Affairs' Water Resources Agency and whose main goal is to prevent or at least minimize flood damage in the Tamshui River basin, cites an additional factor that complicates the challenge of flood control. Like other tributaries of the Tamshui River, the Keelung is a tidal river in which sea water can reach as far as Hsichih at high tide.
The heavy rainfall that has accompanied typhoons in recent years and the impact of various engineering projects in the area have further worsened the situation. Before the Feitsui Reservoir was built in 1987, for example, too much groundwater was pumped in the Taipei basin, causing much of the land to subside and leaving it less resistant to flooding. In addition, the support columns under the more than sixty bridges spanning the river have obstructed the flow of water. "In general, over development along the river is a serious problem," notes Kuo Jan-tai, a professor of civil engineering at National Taiwan University (NTU). "Buildings can be found even on the flood plain and other places that can easily be invaded by floods. A lot of buildings have also been constructed in the past ten years on the slopeland near the river between Hsichih and Keelung. That deprives the land of its ability to retain water, so when it rains, the water quickly collects in the river." Kuo says that the "people of Taiwan have not been serious about soil conservation, and now the land is fighting back."
Measures designed to protect residents along the Keelung River have been carried out for decades. A major milestone was the Executive Yuan's 1973 launching of a comprehensive flood control project for the Taipei area. It adopted a "high -protection standard" (meaning a 0.5-percent possibility of flooding in any given year), with emphasis on the most densely populated region along the river--the lower reaches between its mouth and Nankang on the eastern edge of Taipei City. An important goal of this project was to straighten the section that meandered in bends through the Taipei districts of Nankang, Neihu, and Sungshan, and research on this idea started in 1981. When Typhoon Lynn struck in 1987, dropping huge quantities of rainfall and causing great damage in the Neihu District, the Taipei City Government was motivated to take action. After detailed planning, work started in 1991, and over the next five years the river was shortened by 5.3 kilometers as new river channels were opened and the old ones filled in with soil. Part of the reclaimed land was landscaped into parks, and the rest was used for housing construction, roads, and other public facilities. The project also included the building of high levees to shield much of the eastern part of Taipei from flooding, and the government used the opportunity to redevelop a 5.6 -square-kilometer section originally inhabited by some 13,000 squatters dwelling in unlicensed shacks.
The engineering project aroused considerable controversy at the time. Some argued that a curving river should not be straightened because the bends slow the currents, providing a cushion against floods. "But a lot of research and experimentation had been done by experts in hydraulics for nearly ten years before the plan was executed," says Chen Chia-chin, the chief secretary of the Taipei City Government's Bureau of Public Works. "It certainly wasn't a decision reached in a careless way." Chen regards the river as still quite menacing to riverside residents in Taipei County and Keelung, not because of the river straightening but mainly because the flood control measures undertaken in those areas have yet to reach the high -protection standards adopted downstream. One step that should help ease the flooding problem, he notes, is the plan to move the Chungshan Bridge, which crosses the river at Yuanshan near Taipei's Grand Hotel. The future of the bridge--which dates from the Japanese colonial era and is highly regarded for its architectural design--had been debated for years until the Taipei City Government finally decided to shift it to a still-undetermined location, a task scheduled to begin late this year. While the distance between the levees on the two banks of the river averages 420 meters overall, the bridge stands at a bend where the project for straightening the Keelung River ended. That point is a bottleneck where the distance between the levees is only 110 meters.
In recent years, as rapid development has taken place in towns like Hsichih, increasing attention has been paid to the section of the river outside the city limits of Taipei. But extensive flood control measures were not carried out in those areas until early 1999, when the government decided to implement a preliminary plan dealing with the most worrisome portion, the stretch between Hsichih and Patu. A "low-protection standard," based on a 10-percent probability of flooding, was adopted. Most of the work has now been finished, including the construction of 22.8-kilometer-long dikes and low-level protective banks as well as the dredging of a 5.6-kilometer stretch of the river. Now the Water Resources Agency has drawn up a long-term flood prevention plan that meets a high-protection standard for the entire Keelung River. Once approved by the Executive Yuan, it will become the official guideline that all government agencies must follow.
Some critics have contended that continuing to rely on the traditional approach to flood control--primarily building more levees--would be a big mistake. One of them is Lee Yuan-tseh, a Nobel laureate in chemistry who is president of Academia Sinica, Taiwan's most prestigious research organization. Last September when Typhoon Nari hit the island, Szufen Creek, a tributary of the Keelung River, flooded the Academia Sinica campus in Nankang, causing damage estimated at over NT$200 million (US$5.9 million) plus the suspension of numerous research projects. In response, the city government announced plans to raise the levees on both sides of the creek, but Lee strongly opposed the decision, maintaining that it represented merely a palliative, not a cure.
After prolonged negotiations with Academia Sinica, the Taipei City Government decided this past February to proceed with raising the levees along the creek, but to leave most of a 500-meter-long section flowing through the campus untouched. Having chosen to deal with future floods on its own, Academia Sinica plans to take precautionary measures such as building reservoirs to trap excess water, moving critical facilities to higher stories, and improving its early-warning system to leave more time for anti-flood preparations and, if necessary, evacuation. The reversal of the local government's decision was seen by NTU's Kuo Jan-tai as significant and encouraging. "Developed countries would certainly opt for what Lee is calling for," he says. "They rarely try to stop floods by building high levees."
The question is whether Taiwan can afford immediate abandonment of its long-time flood control policies while faced with the threat of floods of nightmarish proportions. "Everybody knows that containing floods is a bad strategy, but when the situation is so urgent, we have to do it," says Lin Jing-jion, deputy director-general of the Water Resources Agency. "A major obstacle for public works today is the society's mounting consciousness about environmental protection. But over-emphasizing the environment can cause you to neglect the real dangers that threaten people's lives."
A poll conducted in 2000 by a community college in Hsichih provides some indication of what the people actually want. Asked what the authorities should adopt as the priority goals for "fixing" the river, a total of 609 respondents selected one or more options. The highest number--576--chose "precautions against flooding," followed by 405 for "environmental protection" and 264 for "creating more space for leisure activities." Perhaps the construction of high levees would satisfy the wishes of most Hsichih residents, but Kuo Jan-tai observes that many citizens object to the dikes as unsightly structures that mar the natural environment. "Most importantly, the construction of high levees can't guarantee permanent relief from floods," he says. "There'll always be bigger floods than anyone expects."
The voice for alternative methods has already been reflected in the contents of the central government's long-term flood prevention project. One example is the Yuanshantzu Floodway being constructed at the upper reaches of the Keelung River. Once a flood occurs, it is designed to channel one-third of the water volume northward to the sea. Having passed the environmental impact assessment, this NT$6.3-billion (US$180-million) project is slated to be finished by the end of 2004. The government is considering building several other floodways to divert excess water from the upstream section of the river. Other elements of the project include the reconstruction of bridges over the river and its branches, as well as the creation of detention basins at eight locations along the Keelung River covering a total of 115 hectares. Situated in low-lying, undeveloped spots, these detention basins will store rainwater and prevent it from flowing into the river, and will also double as venues for recreational activities.
"Some other parts of the plan, though unrelated to public works, are equally important," says Chang I-min, deputy director of the Tenth River Basin Management Bureau. He cites plans to improve the flood alarm system in the river basin at a cost of NT$66 million (US$1.9 million) and to control the use of land in a 7.7-square-kilometer area flooded by Typhoon Xangsane. To tackle the flooding problem at its root, the plan also sets aside 230 square kilometers of slopeland in the river basin for soil conservation purposes.
For the foreseeable future, the concrete embankments will still be relied upon as a major method of flood prevention. "But we're quite aware of the importance of creating a more natural environment which doesn't block public access to the water," notes Lin Jing-jion of the Water Resources Agency. The priority objective is to assure the safety of all residents living by the river. Once that is achieved, the agency will begin to pay more attention to the goals of beautifying and humanizing the environment.