International disaster experts have concluded that a major vulnerability in natural catastrophes lies hidden beneath our cities.
As the world's cities get bigger and land more expensive, more vital services and structures end up underground. These crucial subterranean networks of electrical generators and lines, communications equipment, computers, subways, parking garages, sewer lines, and roads are vulnerable to massive flooding and earthquake damage.
If those critical services are flooded or wiped out in a tsunami, such as the one that hit South Asia last month, a city could be paralyzed, two researchers from the United Nations University say in a study to be presented at an international disaster conference next week in Kobe, Japan.
"We have a danger underground; we made ourselves vulnerable" by more underground construction, co-author Srikantha Herath, a United Nations University researcher based in flood-prone Tokyo, told Knight Ridder. "One of the biggest problems is that many, many commercial establishments tend to put their electrical equipment underground."
Especially worrisome is the concept of a crowded subway train trapped by sudden flooding or an earthquake, said study co-author Janos Bogardi, the director of the Institute for Environment and Human Security in Bonn, Germany, which is part of the United Nations University, a research center.
In the United States, two major underground-flooding incidents in recent years proved costly. In 1992 in Chicago, a construction accident flooded 50 miles of underground freight tunnels. In places, the water was 40 feet deep. The flooding nearly shut down the city for three days. Damage was set at $1.95 billion.
In June 2001, Tropical Storm Allison flooded downtown Houston. One woman drowned when she opened the door to a flooded underground parking garage and was swept away.
The flooding badly damaged the University of Texas Medical School at Houston, Baylor College of Medicine and the Memorial Hermann Hospital and closed them for weeks, said Dr. Chris Smith, the University of Texas Medical School's director of veterinary medicine.
From 1999 to 2001, Tokyo flooded underground 17 times, and a few of those times people died, Herath said. Dresden, Germany, and Prague, Czech Republic, saw deaths and major paralysis from underground flooding in 2002, Bogardi said.
Smith said that as her university rebuilds, "all of the critical machinery for the building has been placed aboveground."
The solution to underground problems isn't necessarily moving everything aboveground because there also are problems being up high, especially in hurricane-prone areas, Herath said. The key is better warning and planning, he said.