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. Coastal regions are prone to destruction at the historic levels of Hurricane Harvey, Hurricane Sandy, and Hurricane Katrina. Lowlands near rivers and lakes are also vulnerable. Indeed, flooding can happen anywhere it rains.

As cities grow, floods become more frequent because urban infrastructure cannot accommodate the drainage needs of land that's paved. Flat, highly developed areas like Houston,Texas leave water with nowhere to go. The predicted rise in sea levels jeopardizes streets, buildings, and subway tunnels in coastal cities like Manhattan. 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 promising technologies for flood control.

In England, engineers designed 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.

Surrounded by water, the island nation of Japan has a long history of flooding. Areas on the coast and along Japan's rapidly-flowing rivers are especially at risk. To protect these regions, the nation's engineers have developed a complex system of canals and sluice-gate locks.

After a catastrophic flood in 1910, Japan began exploring ways to safeguard the lowlands in the Kita section of Tokyo. The picturesque Iwabuchi Floodgate, or Akasuimon (Red Sluice Gate), was designed in 1924 by Akira Aoyama, a Japanese architect who also worked on the Panama Canal. The Red Sluice Gate was decommissioned in 1982, but remains an impressive sight. The new lock, with square watch towers on tall stalks, rises behind the old.

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

The Netherlands, or Holland, has always battled the sea. With 60% of the population living below sea level, dependable flood control systems are essential. Between 1950 and 1997, the Dutch built Deltawerken (the Delta Works), a sophisticated 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).

Another 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.

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. For success stories in the United States, check out the Fox Point Hurricane Barrier, where three gates, five pumps, and a series of levees protected Providence, Rhode Island after Hurricane Sandy's powerful 2012 surge.