How Engineers Stop Floods: High-Tech Solutions for Flood Control

Every year a community in some part of the world is devastated by catastrophic flooding. Communities in coastal regions and land near rivers and lakes are especially prone, but flooding can happen anywhere it rains.

As cities grow, flooding becomes more frequent because their infrastructure cannot accommodate the drainage needs of land that's paved and highly developed. Moreover, aging dams and levees are prone to failure, leading to the kind of devastation that New Orleans saw after Hurricane Katrina.

There is hope, however. In Japan, England, the Netherlands, and other low-lying countries, architects and civil engineers have developed innovative new technologies for flood control.

Next: Water Gates in Japan

Surrounded by water, the island nation of Japan has suffered devastating floods. Communities along Japan's rapidly-flowing rivers are also prone to flooding.

For many years, the picturesque Iwabuchi Floodgate, or Akasuimon (Red Sluice Gate), protected lowlands in the Kita section of Tokyo. The Iwabuchi Floodgate was designed in 1924 by Akira Aoyama, a Japanese architect who also worked on the Panama Canal, and remained in service until 1982. Newer gates were constructed directly behind the historic Iwabuchi Floodgate.

Automated "aqua-drive" motors power many of the watergates in flood-prone Japan. Water pressure creates a force that opens and closes the gates as needed. Aqua-drive motors don't use electricity, so they aren't affected by power failures that can occur during storms.

Learn more:

• Unlocking the secrets of Kita by Kit Nagamura, The Japan Times, May 5, 2006
• Iwabuchi: A proud town founded on ferries by Sumiko Enbutsu, The Japan Times, October 17, 2002
• Floodgates in Japan Photos
• New Water Gate Hoist Model Driven by Hydraulic Motors

Next: The Thames Barrier

In England, engineers developed an innovative movable flood barrier to prevent flooding along the Thames River. Made of hollow steel, water gates on the Thames Barrier are normally left open so ships can pass through. Then, as needed, the water gates revolve shut to stop water flowing through and to keep the level of the Thames River safe.

The Thames Barrier gates were constructed between 1974 and 1984 and have been closed to prevent floods more than 100 times.

Next: Eastern Scheldt Storm Surge Barrier

The Netherlands, or Holland, has a long history of battling the sea. With 60% of the population living below sea level, sophisticated flood control systems are essential. Between 1950 and 1997, the Dutch built Deltawerken (the Delta Works), a complex network of dams, sluices, locks, dikes, and storm surge barriers.

One of the most impressive Deltaworks projects was the Eastern Scheldt Storm Surge Barrier, or the Oosterschelde. Instead of building a conventional dam, the Dutch constructed the barrier with movable gates.

After 1986, when the Eastern Scheldt Storm Surge Barrier was completed, the tidal height was reduced from 3.40 meters (11.2 ft) to 3.25 meters (10.7 ft).

Next: The Maeslant Storm Surge Barrier

Another impressive example of Holland's Deltaworks is the Maeslantkering, or Maeslant Storm Surge Barrier, in the Nieuwe Waterweg waterway between the towns of Hoek van Holland and Maassluis, Netherlands.

Completed in 1997, the Maeslant Storm Surge Barrier is one of the largest moving structures on Earth. When water rises, the computerized walls close and water fills tanks along the barrier. The weight of the water pushes the walls firmly down and keeps water from passing through.

Next: The Hagestein Weir

Learn More: Maeslant Storm Surge Barrier Information Center

Completed in about 1960, the Hagestein Weir is one of three movable weirs, or dams, along the Rhine River in the Netherlands. The Hagestein Weir has two enormous arch gates to control water and generate power on the Lek River near the village of Hagestein. Spanning 54 meters, the hinged gates are connected to concrete abutments. The gates are stored in the up position. They rotate down to close the channel.

Dams and water barriers like Hagestein Weir have become models for water control engineers around the world.

Return to Beginning: Floods Are on the Rise

Learn More: California Turns to Holland for Flood Expertise, on National Public Radio, January 14, 2008