Tag Archives: flood prevention

Natural Restoration is the Key

Here is some of an article written for The Korea Times, by local conservationist and fellow Birds Korean, Tim Edelsten :


“Anyone who has spent time in the Korean countryside over the past decade, as I have, knows that a traumatic and unprecedented transformation has been inflicted on the nation’s waterways.

Almost every river and stream, up to the smallest mountain trickle, has been modified into straight lines of concrete trenches. The reason given for such a radical and wide-scale bio-engineering project was “flood prevention.”

From what I have seen, however, much of this construction was unnecessary, environmentally-damaging, and obviously very costly. It may have been merely a job-creation exercise for the powerful construction industry. It may have actually increased the risk of flood damage to the nation.”



“Even a decade ago in Korea, it was easy to find beautiful and untouched waterways bursting with life, fringed by reeds and picturesque willow trees. Such watercourses meandered naturally, their flow slowed by aquatic vegetation ― nature’s water-purification and filtration service.

In the uplands, smaller creeks intercepted rainwater, pooling and collecting it in stages before gradually releasing it to the lowlands. Such brooks often held clean, potable water year-round. In the lowlands, rivers transported fertile sediments to agricultural land. This was a stable equilibrium, a self-sustaining system, in place since time eternal.

This has been replaced virtually overnight, however, by the insertion of thousands of kilometers of concrete ditches and channels countrywide. In many cases such drains are built running vertically down mountainsides. These sterile structures are not only ugly, but do not support fish, frogs, insects or vegetation, thus eliminating swathes of flora and fauna in the countryside.

They also form inescapable death traps for wildlife, such as deer, that happen to fall into them. Such lifeless stretches are also useless to fishermen. Neither do they perform flood prevention, because they prevent rainwater from permeating into the ground ― and also increase the velocity and force with which it rushes downstream.

In the event of heavy rainfall, this massive instant runoff creates a far greater, sudden storm surge downstream, as we saw along the Han River in Seoul last week. Peak flood events are thus set to become more dangerous. The U.S. Environmental Protection Agency said, “When wetlands are converted to systems without water retention capacity, downstream flooding problems increase.”
On the larger low-lying rivers, bulldozers have spent the last decade systematically stripping away the natural flood defenses. In many cases riverbanks have been cleared of the deep-rooted trees that held them secure, and a superficial layer of concrete or brickwork has been applied.”


You can read the complete article from Tim Edelsten, here, at The Korea Times.