Flood Control Requires Understanding:
Using Our Heads Beats Spending Our Money
China Times editorial (Taipei, Taiwan, Republic of China)
September 6, 2013
Summary: Recently the central government blasted local governments. It said per capita local government funding for flood control was "not even enough to buy a hard-boiled egg" and that the inadequate flood control budget left people deeply alarmed. The central government's gesture exposed local government emphasis on public works at the expense of flood control. But it also muddied the issue of flood control.
Full text below:
Recently the central government blasted local governments. It said per capita local government funding for flood control was "not even enough to buy a hard-boiled egg" and that the inadequate flood control budget left people deeply alarmed. The central government's gesture exposed local government emphasis on public works at the expense of flood control. But it also muddied the issue of flood control.
Politics distinguishes between Blue and Green. Politicians demagogue the issues. But Mother Nature is utterly indifferent to all of this. Rain falls wherever it wants. The only immutable truth is "Water seeks its own level." If it cannot find a way out, flooding follows. It makes no distinctions whatseover between Blue and Green. In this it is ruthlessly fair.
Central government fiscal constraints make it impossible to continue past flood control budget practices. Otherwise it would not have declared this all out war of words on local governments. In the past, Taiwan adopted a "man must conquer nature" approach to flood control. But change is long overdue.
Global warming and extreme climates mean more fequent and prolonged droughts followed by heavy rains. Traditional 20 to 50 year flood control remediation standards are no longer adequate. Maximum rainfall in Tainan recently reached 100 mm . This far exceed the system's design specifications. Few drainage systems in the world can handle such loads. In the future, there may be rainfall that does not cause flooding. But there will no longer be flood control systems immune to flooding.
Everyone is familiar with the legend of Da Yu. Flood control practice is complex. But flood control principles are simple. If one occupies the hight ground, one can rely on gravity for drainage. As long as one provides proper channels, water will take advantage of the opportunity to flow downward. If one occupies low-lying areas below sea level however, one must rely on dikes, pumps, and other means to eliminate the water.
The Nantou storm drain system is poorly designed. But Nantou occupies the high ground. During the recent typhoon, and inadequate and overburdened storm drain system turned the streets into defacto storm drains. The streets enabled the flood waters to flow to low-lying areas. Although the streets were temporarily flooded, it did not result in disaster. For Nantou flooding is not the worst problem. Preventing landslides in the mountain regions is more urgent and more difficult. Low-lying areas have the opposite problem. The entire area is below sea level. More storm drain construction would do nothing to solve their problem. As long as water volume exceeds pumping capacity, flooding is inevitable.
The situation differs for urban and rural areas. Over the past decade , scholars have been promoting the "sponge city" concept. This would increase the city's permeability. This would allow water to flow, not just through the storm drain system, but through parks, greenbelts, rainwater wells, high coefficient of permeability pavements, and even soil through vertical absorption, enabling it to become groundwater .
Low-lying coastal village remediation requires a comprehensive upstream, midstream, and downstream solution. This includes upstream watershed management and forest conservation to ensure more natural water retention. It also includes midstream and downstream retention, reducing peaks downstream water. It includes ensuring that water downstream has more than one place to flow.
The most difficult problem is changing low-lying area land use patterns, to prevent the situation from further deteriorating. But this often affects people's property, livelihoods, and their emotional attachment to the land. One must also create new economic conditions in the region. Given electoral pressures, almost no local leader or elected representative will be willing to take on this thankless task. Therefore the WRA will allocate huge sums of taxpayer dollars to build breakwaters and protect coastal fish farms. But meanwhile the Council of Agriculture will ignore the paradoxical scenario of fish farms pumping out groundwater. As Minister of the Interior Li Hong-yuan noted, this manner of flood control means that even another 600 billion would be inadequate.
Rivers on Taiwan are short. Water flow is swift. Water supplies are inadequate. Yet public awareness of the need for water conservation is almost non-existent. Sewage treatment produces reusable "gray water." But it is dumped into the sea. No one considers recycling rainwater. The public does not value water. It does not think about water. It does not treat water resources as something precious. It has no concept of water. Naturally water has become a problem.
When the MRT Taipei Main Station flooded, President Ma noted how it "unwittingly functioned as a detention pond." He was met with strong criticism. But his remark highlighted a problem. President Ma had only a superficial knowledge of flood control. A good detention facility must function when flood waters threaten. But they must also benefit the public in normal times. . The government should amend the relevant laws and regulations. It can then establish new water permeability standards for new developments. It can modify the building codes. It can require new materials, additional rainwater storage towers, and stormwater pipelines. The water can be used to flush toilets or water plants, reducing the load on the system during floods. These measures would be far more effective than simply increasing government budgets.
Low-lying area remediation must begin with national land planning, changes in urban planning, land readjustment, and zone expropriation. It requires changes in land use, and the creation of new values and lifestyles. Central and local governments must ensure a clear division of labor on individual projects. They must overcome difficulties in communication. They must determine who is responsible for implementation. They must establish detailed timetables.
The public views zone expropriation as a scourge, Therefore this is sure to be a long, hard road. But it is the only viable approach. The traditional practice of throwing money at the problem is entirely beside the point.