It was the beginning of September in 1963 when Super Typhoon Gloria scored a direct hit on northern Taiwan.

Ching-ming Wang, a professor in the Graduate Institute of Environmental Education at National Taiwan Normal University (NTNU), who was seven at the time, remembers taking cover with his family in the attic while listening for the latest news on the radio. He has never forgotten the sight of his house's furniture floating around or the vast expanse of water that had accumulated outside.

Gloria dumped 1,375mm of rain on northern Taiwan during 20 consecutive hours of precipitation, and along with water released from the newly completed Shihmen Reservoir, it kept northern Taiwan from Taipei to Miaoli submerged for three days and three nights.

The storm not only changed Wang's childhood but also forced his entire village to be relocated to Taishan Township. It also rewrote Shihmen Reservoir's destiny.

Before Shihmen Reservoir was completed, engineers estimated that silt would flow into it at a rate of 790,000 cubic meters per year, giving it a useful life of at least 71 years. The reservoir began filling with water in May 1963, but when Typhoon Gloria struck northwestern Taiwan in September of the same year, it washed more than 19 million cubic meters of silt into the new reservoir, equivalent to one-third of its silt capacity. This knocked 23 years off its life expectancy at a stroke.

The disaster Wang experienced over 40 years ago remains vivid in his mind to this day, but what he did not expect was that, at the age of 55, he would be confronting Shihmen Reservoir again. Today, as an engineering expert, he is part of a small task force pushing a NT$25 billion "Shihmen Reservoir and Catchments Management Project" to help control the aging stronghold.

Taiwan's Riskiest Reservoir

Entering middle age, Shihmen Reservoir poses the highest level of risk of any in the country. Originally designed to hold a capacity of 300 million cubic meters of water, it has already accumulated 90 million cubic meters of silt, cutting its capacity by nearly a third. Also, the 123 sabo dams (used to trap silt and debris) built on the Dahan River upstream from the reservoir are completely full.

Even the Jung-hua Dam, considered the last straw in protecting the reservoir, is in a precarious state. Silt has accumulated as high as the dam's 82-meter wall, enough to bury a 28-story building. Hong-Yuan Lee, a river hydraulics specialist in National Taiwan University's Department of Civil Engineering, who has studied Shihmen Reservoir a number of times, warned that if the Jung-hua Dam breaks, 12 million tons of silt will rush into the reservoir area and further shorten its life span.

Shihmen Reservoir's future has major implications for northern Taiwan. Situated in the country's most densely populated area, it provides potable water to 4 million people and could affect the lives and property of 8 million people. If it were to burst, much of northern Taiwan, including Taoyuan, Taipei, Sansia, Tucheng, Banciao and Wanhua, would be endangered.

Keeping Reservoirs Alive with Good Management?

This high-risk reservoir is merely a microcosm of the country's situation. Reservoirs feeding potable water in southern Taiwan have no way of dodging similar fates. Water Resources Agency deputy director Fong-Rong Yang pulled out the latest statistical study indicating that Wushantou Reservoir's sedimentation rate exceeds 47 percent, and Tsengwen Reservoir's is 34 percent, reducing its capacity from 700 million cubic meters to below 500 million.

One-third of Nanhua Reservoir, which came on line in 1999, has been filled with silt in a mere 10 years, dealing a blow to the water supply in Tainan and Kaohsiung. Because of that, Taiwan's Legislature approved a six-year NT$54 billion project on April 20 to manage the Tsengwen, Nanhua and Wushantou reservoirs and stabilize southern Taiwan's water supply.

But some are skeptical that aging reservoirs can be kept alive simply through intensive management. Hongey Chen, a professor in National Taiwan University's Department of Geosciences, says disapprovingly that the only reason management measures are needed is because the reservoir's natural environment has been wiped out. Management methods are required to overcome the ills of over-development, setting off a vicious cycle.

"Management controls all focus on a single target, but managing one spot may generate an effect comprehensively, or cause instability in other spots. This is absolutely obvious at Shihmen Reservoir," says Chen, who has also conducted research at the reservoir on several occasions.

The Concrete Monster of Management

Could Shihmen Reservoir's management experience eventually mirror problems that will surface at other reservoirs in Taiwan? Driving along Taiwan's Provincial Highway No. 7, one reaches the Shihmen Reservoir catchment area, the "backyard" of northern Taiwan's people. Liang Yin-min, who came to Taiwan in 1970 as an overseas student and planted roots here after graduating from National Taiwan University, discovered three years ago that this northern cross-island highway was peppered with "concrete monsters."

Pointing to the Sule River ahead, he asks three times, "Is that still a river?"

An upstream tributary of the Dahan River at an elevation of 640 meters, the Sule River is a classic consequence of reservoir management. Standing at the base of collapsed land is a slit dam, looking like a comb standing on edge, while further downstream, the river's banks are supported by reinforced concrete, and more than 10 "ladder-type" silt dikes are lined up over a short span of 500 meters. Looking back at the scene from the unfinished Sule Bridge, the river looks like a long drainage ditch.

Liang sighs deeply as he surveys the situation, saying only, "This is too much." Although the civil engineering project is designed to prevent river water from washing loosened silt into the reservoir area, Liang shakes his head in thinking about the potential damage caused by the plan.

"Building artificial embankments will only cause more collapses. When heavy rains come, won't everything be washed away?" he wonders.

Liang, Chen Ru-dong and Hsu Chan-chuan, who founded the nongovernmental group Flood Management Monitoring Alliance three years ago, became involved in the Shihmen Reservoir task force after NTNU's Wang proposed the participation of civic groups.

But it was too late to stop the trend toward managing local rivers with construction and cement. Any tributary, no matter how big, can be found today with multilayered silt dikes, one after the other, looking like Lego blocks lined up in a row.

No Fighting Natural Forces

There have yet to be any typhoons in Taiwan this year, but on the road from Fusing Township in Taoyuan to Jianshih Township in Hsinchu, there are plenty of spots where stones and gravel have fallen repeatedly to the ground. Before arriving in the Atayal tribal village of Fuhua in Sanguang village, the road next to a sign reading "Third Stage Project on Teirek River" is severely damaged. Large and small rocks alike slide down the mountainside randomly, filling passing motorists with fear, wondering if the road is safe.

The mountain slopes in the village have already been subject to repeated slope protection measures, but because of the loosening of the earth, "the measures hold for at most one or two years," says one resident. "Once the rains come, the earth collapses again."

Clearly, projects designed to protect mountain slopes cannot withstand nature's natural power.

But in fact, many problems should not be solved with construction projects, and large amounts of cement do not necessarily protect the environment. Instead, utilizing an area's natural topography and ground features generally yield better results for longer periods of time. Some observers, however, accuse the Soil and Water Conservation Bureau, responsible for dredging streams, and the Water Resources Agency, responsible for riverbed management, of resorting exclusively to construction projects whenever difficulties arise.

NT$25 billion in funding earmarked for rehabilitating Taiwan's rivers has been used entirely on engineering projects, including building sabo dams, buttressing collapsing soil, and, in downstream areas, laying piping, expanding water purification plants and developing multiple water inlets.

These initiatives have had only limited success. Yu Fan-Chieh, a professor in National Chung Hsing University's Department of Soil & Water Conservation, believes the increasing amount of silt in Taiwan's reservoirs is inevitable, limiting the value of dredging.

He says all watershed management projects are designed to slow the pace and volume of silt displacement and extend the life and sustainable use of reservoirs before they burst. But all of this effort may be futile.

"If another natural disaster like Typhoon Aere comes along, all the little bank deposits may get withdrawn in an instant – everything will get washed into the reservoir," worries Flood Management Monitoring Alliance's Chen Ru-dong, who heads the group's task force on Shihmen Reservoir.

Man-made Natural Disaster

Chen Ru-dong, who frequently "patrols" the catchment areas, believes that the government's management efforts are short-term remedies targeted at symptoms rather than directed at the root causes of problems.

In fact, when torrential rains fall, landslides will occur no matter how remote or natural the area. Collapses will occur wherever there is heavy precipitation, meaning the government's role should be to mitigate disasters, the activist contends.

The source of disasters is humankind. Where there are people, there is life and consequently economic activity. This is evident in the area surrounding Shihmen Reservoir, where two main problems exist. One is agriculture, with peaches, bamboo and vegetables widely grown nearby. The other is tourism, which has encouraged the development of residential housing units and roads to attract visitors. Both phenomena are responsible for heavy water and soil erosion.

"The guesthouses there are almost all illegal. The problem is a management problem. Bamboo is grown in places where it's not allowed, private agricultural roads are opened where there shouldn't be any, and trout are raised in the middle of the river. The Taoyuan County government is unable to solve these problems," says Chen Ru-dong with mixed feelings. He sighs before adding, "The problem is not that there are no laws that can cope with the problem. It's that the situation is poorly managed."

Shielding Expertise from Political Interference

National Taiwan University's Hongey Chen also has strong words for the authorities. "The government is the initiator, first developing tourism and then promoting ‘management' afterwards. Isn't this putting the cart before the horse?"

National Chung Hsing University's Yu, who is also a member of the Shihmen Reservoir task force, contends that passing a special budget to rehabilitate reservoirs is not necessary from either a social or economic perspective.

He believes the most important consideration is to return to fundamentals – limiting human encroachment in catchment areas and making sure government agencies shoulder their responsibilities. "Calling for a special budget only after something happens, that's a game that politicians play," he argues, insisting that expertise cannot always be overshadowed by political interference.

From Shihmen to Tsengwen, Wushantou and Nanhua reservoirs, nearly NT$100 billion has been spent on water management and supply projects, but has that funding protected us any better or made us any safer?

NTNU's Wang's many years of participation in the Shihmen Reservoir project has only deepened his impression that as the climate and geological conditions change, the tug-of-war between man and the land will only grow more intense. The only sustainable solution, he believes, will be to require strict land use management and zoning.

"As long as there is no national land planning, all management will be done on a piecemeal basis, responding only to emergencies," he concludes.

Translated from the Chinese by Luke Sabatier