Flood Control Requires Understanding: Using Our Heads Beats Spending Our Money

Flood Control Requires Understanding:
Using Our Heads Beats Spending Our Money
China Times editorial (Taipei, Taiwan, Republic of China)
A Translation
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.

中時電子報 新聞
中國時報 　2013.09.06
社論－治水要先知水 花大錢不如換腦袋
本報訊

    　近日，中央政府火力全開批評地方，編列的人均治水經費甚至「買不到一顆茶葉蛋」，治水預算低得讓人「毛骨悚然」。中央此舉固然揭開了地方要工程、輕治水的部分面紗，卻也模糊了治水的全貌。

    　政治分藍綠、政治人物噴口水，老天爺可不管這一套，雨要下哪、就下哪，「水往低處流」才是唯一不變的真理，流不出去就淹水，絕對不分藍綠，公平得很。

    　如果不是中央財政拮据，實在沒有辦法再按照過去的手段編列治水預算，恐怕未必會大張旗鼓地和地方打這場口水戰。但實際上，台灣過去完全從工程出發，力求「人定勝天」的治水思維，也早就到了不能不改的地步。

    　面對全球暖化、極端氣候的大環境，久旱、暴雨出現的頻率一定會越來越高，過去傳統以20年或50年洪水頻率為基礎的整治設計，也將越來越不足恃。這次台南新營最大時雨量達到100毫米，不僅遠超過系統的設計，全球大概也沒有幾個排水系統能夠承受。幾可斷言，未來只有不淹水的雨量，不會有不淹水的系統。

    　大禹治水的故事，每個人都耳熟能詳。治水問題複雜，原理卻很簡單。地勢高的地方，靠重力排水，只要有適當的渠道，水就會順勢往低的地方走；至於地勢低於海面的地方，就只能靠堤防、抽水機等外力，把水抽掉。

    　以這次地方點名雨水下水道建設最不力的南投為例，因為地勢高，雨水下水道不足或是不堪負荷時，水自然就會把馬路當水道，往地勢低的地方走，雖然會淹水，卻不等同於會造成災情。對南投而言，相較於淹水問題，土石流、治山防洪可能更急迫、棘手。至於低窪地區，問題則剛好相反，整個地區都在海平面以下，再多下水道建設也解決不了問題，只要水量超過抽水機的負荷，就非淹不可。

    　都市與鄉村的情況則又不同。近十幾年來，學界不斷提倡「海綿都市」的概念，要增加城市的透水率，讓水除了經過排水系統水平流出之外，還能經公園、綠地、雨水井、透水係數高的鋪面，垂直的被土地吸收，甚至挹注地下水。

    　而沿海低窪的鄉村的整治，就必須要上中下游整體解決，上游治山、森林保育，讓更多的水能夠被大自然留住；中下游的滯洪規畫，降低瞬間到下游的水量，也讓到下游的水多一個去處。

    　最困難的是，如何改變低窪地區的土地利用方式，讓問題不再繼續惡化，但這方面往往涉及人民的財產、生計、土地情感等因素，還必須要有建立當地新經濟型態等多方條件的配合，在選票壓力下，幾乎沒有任何地方首長、民代願意做這種吃力不討好的工作。於是就會出現水利署拿納稅人大筆的錢蓋離岸堤，保護沿海的魚塭，而農委會卻繼續漠視魚塭抽地下水，維繫養殖戶生計的荒謬景象。正如內政部長李鴻源所說，如果還是這樣治水，再編6000億都不夠。

    　台灣的河川短而急，水資源其實相當缺乏，但國人節水的觀念卻相當薄弱，汙水處理後可利用的「灰水」全部放流出海，國人生活中也從來沒有「利用雨水」這回事。不親水、不知水、不珍惜水資源、沒有與水共生的概念，自然就不可能治好水。

    　馬總統以捷運和台北車站淹水，「不知不覺扮演了滯洪池的角色」，遭到強烈的批評。背後凸顯的，馬總統自己對治水的一知半解。一個好的滯洪設施，不能僅在洪水來時發生效用，更必須在平時對民眾有益。其實只要政府修改相關法規，就可以要求新開發區域的透水率；也一樣可以修改建築法規，要求新建物必須增設雨水儲存池（塔）及雨水管線，用作沖馬桶、澆花之用，同時也減少洪水時系統的負荷，這遠比政府編列預算更能立竿見影。

    　至於低窪地區的整治，則必須要從國土規畫出發，以都市計畫變更、土地重劃、區段徵收等手段，改變土地的利用，創造新的價值和生活型態。中央與地方必須要就個別計畫清楚的分工，哪些困難的業務與溝通各該誰負責執行，並訂定詳細的時間表。

    　雖然以目前民眾視區段徵收如洪水猛獸的社會氛圍，這勢必是一條漫長崎嶇的道路，但恐怕也是唯一可行的道路。至於傳統花大錢做工程的作法，就大可不必了。