Building better dikes

So far this year, floodwaters from the Oder River, which defines part of the German-Polish border, have taken the lives of 18 people in Poland. As the waters advanced into eastern Germany, many feared the results there could have been the same or worse. But thanks to an estimated 220 million euros ($270 million) spent on renovating dikes on the Oder River after widespread devastation in the 1997 flooding, they have not had as bad an effect on the state of Brandenburg

Still, there remains a cause for concern. According to Klaus Piroth, a flood control expert at the German engineering firm Arcadis, only 90 percent of the dikes along the Oder River were renovated, leaving some places still open to flooding.

Scientists focus on different techniques

Dikes are not modern inventions. People have been building them for hundreds of years to help regulate water flow.

"The best way to prevent and control flooding is through well-designed dikes," said Igor Liska, an expert at the International Commission for the Protection of the Danube River (ICPDR), an organization that coordinates the flooding prevention measures of the 14 countries through which the Danube River flows.

For the Danube, the ICPDR focused on ensuring that any measures undertaken by one country do not cause another area to bear the brunt of the floods. Therefore, instead of only building higher and stronger dikes, dikes have been built further away from the river to give the water more space. In addition, higher and stronger dikes are not always a solution for rivers because they increase velocity of the current and increase the risk of floods to those living downstream, said Piroth.

A new generation of dikes?

But recent research on flood control has focused on not only improving the manner in which dikes are built, but also on creating dikes that can be easily monitored by engineers and scientists.

Piroth, who is currently writing a book on 21st century dike technology, said that the future of dikes will involve an online monitoring system.

Sensors in the form of a fiberglass will be placed in a synthetic fabric along the length of the dike. The sensors will measure the current, and if conductivity increases, the sensors will set off an alarm that will allow the engineers to know that there is problem in the dike. This would allow engineers to respond to the problems in its initial stages without the help of dike runners – people inspecting leaks in dikes.

Though scientists expect climate change and rising waters to lead to more flooding, "smart dikes" are unlikely to become commonplace in flood prevention, said Karel Heynert, an expert at Deltares, an independent Dutch research institute for water issues. Sensors have only been used in pilot cases and it is unlikely that they will be rolled out on a wide basis because the cost would be too high.

Still Piroth feels that these sensors will be placed in dikes in high-risk areas, especially along the Rhine in western Germany, where flooding is a risk to millions of lives. For now, flood control experts will continue to focus on the strength of dikes, and dike runners will inspect the structures for leaks.

"More could have been done in Poland if dikes were wider and stronger," Heynert said.

The wider and stronger dikes have helped lessen the devastation in Germany, and experts hope that they will continue to do so.

Author: Chiponda Chimbelu
Editor: Mark Mattox