Mon, Jul 26, 2004 - Page 8 News List

Flood prevention not an easy task

By Wang Yung-chen王永珍

With floods brought by Tropical Storm Mindulle sweeping away many facilities which aimed at preventing such flooding, the safety of river ecotechnology is once again being questioned.

Over the past few days, experts and academics have expressed their opinions in favor of or against ecotechnology, but this is little known in the media.

It seems difficult to come to a conclusion about which opinions are correct and which are not.

The current thinking on flood prevention engineering can be divided into two categories.

The first category is directed by the Cabinet's Public Construction Commission and it unites domestic ecological and landscaping experts and academic institutions in the promotion of ecotechnology.

The other category consists of civil and hydraulics technicians and traditional hydraulics engineers. Throughout their training, these people have have become well-versed in the "security first" concept.

They use traditional building techniques, and have problems identifying with the practitioners of ecotechnology.

These engineers come under pressure to accept responsibility when flood prevention fails, but they believe the behavior of rivers is ultimately not their responsibility.

Because many engineers do not obtain evidence by exploring river morphology, hydrology and other factors, their suspicious attitudes toward ecotechnology are unfounded.

What's more, ecotechnology in river management is

often rigid in its application

and damages river biology

without exploiting the river's

advantages.

Unless a fundamental solution to this problem can be found, it will be difficult to build a consensus. In the following, I will list the many misconceptions of ecotechnology.

First is the biased approach among engineers.

Ecotechnology is not, in fact, another word for using more vegetation, paving river banks with stone or doing away with concrete.

Engineers in general are of the opinion that ecotechnology is insufficient when it comes to preventing floods, and although advanced countries repeatedly advocate the application of ecotechnology to revive the ecology in rivers and base this advocacy on evidence, engineering agencies contend that river and hydrological conditions are different, and there is simply no way examples from other countries can be applied domestically. Not every river in Taiwan experiences great floods and embankments are often unnecessary.

If needed, however, embankments don't necessarily have to be made of rigid concrete.

The reason river embankments are destroyed by flood waters may be because those sections are located in dangerous areas, or it could also be related to excessive human exploitation of the environment.

What's more, concrete also has its limitations when used for embankments. Concrete easily breaks when flood waters flow directly at them.

Hydraulics engineers in other countries do not think concrete is a a cure-all for flooding.

They will apply different kinds of hydraulics and hydrological analysis to find ways of reducing, or completely eliminating, the use of concrete in flood prevention projects. Nor do they believe that ecotechnology is an inferior form of flood prevention.

What we should review what is method is appropriate based on the conditions in a given area. In places unsuitable for the application of ecotechnology, a combination of it and more traditional methods should be employed.

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