Why is Houston so vulnerable to flooding?

Floods cause greater property damage and more deaths than a hurricane's winds or tornadoes. Hurricane Harvey produced more than 50 inches of rainfall over the Houston area, which was not equipped to handle such a large amount of precipitation.

"Topography plays a key role because water level rises and it needs some place to go," said Alan Blumberg, a professor of ocean engineering at Stevens Institute of Technology. Flooding is still an issue even though Houston sits well above sea level, he said.

"Because the topography of Houston is so flat, when water starts to come in from the ocean or from precipitation, it just floods the entire land," he said.

Houston stretches out over 600 square miles and is growing. Blumberg said that the expanding roads, parking lots, and building structures are making the city more vulnerable to flooding.

"In the past, Houston had a lot of areas where water could go – into the bayous, into areas that now are cemented over and buildings exist," he said. "So that water that used to go into a bayou, or to a low area, can't go there anymore and it starts to move into areas that weren't flooded before."

In a process called storm-water management, the policy, planning, engineering, and maintenance of urban water systems is implemented to deposit rainwater runoff. Building structure can also play a preventative role.

"To build buildings that are designed in a way to block the water on their own," Blumberg said. "Not to put one next to the other, maybe at an angle so that the waves are blocked and pushed back into the water."

This is something the people of Houston may consider as they start to rebuild.

"The events are only going to get worse. As our climate changes and gets warmer in the atmosphere, the ocean gets warmer," Blumberg said. "Warm water leads to stronger hurricanes. So we're all doing this to each other and we have to figure out a way to do it together."

Blumberg said a similar problem can happen in cities around the world, including lower Manhattan, Miami, and Norfolk, Va., for example. The low-level topography in relation to the ocean exacerbates the problem of flooding.