The Hindu Business Line : Mississippi bridge crash, a grim reminder of vulnerabilities

Chennai, Aug. 8 In the aftermath of last week’s collapse of an eight-lane inter-State bridge in Minneapolis, Minnesota, which fell into the Mississippi river, leaving seven dead, several injured and at least eight persons missing, the question that’s being asked across America is: Can we trust our bridges?

According to reports, the authorities have decided to embark on a thorough check of all bridges and overpasses throughout the country, in the wake of the collapse of Interstate 35W bridge, the busiest in the State, one that linked downtown Minneapolis to northern suburbs.

Conspiracy theories are already flying thick and fast; many Web sites have been pointing out that bridges such as the New York’s George Washington Bridge, San Francisco’s Golden Gate Bridge, the Brooklyn Bridge, the Chesapeake Bay Bridge in Maryland and the Mackinac Bridge in Michigan have been on the target list of terror outfits for some years now.

(The Mackinac bridge, five miles long and 50 years old, is the longest suspension bridge in the Western Hemisphere and connects Michigan’s upper and lower peninsulas.)

While the latest incident does not seem to have any link to terrorist activity, it comes as a grim reminder of the vulnerability of US infrastructure to low-tech, high-impact attacks, says Mr Ralph Sawyer, an independent historical scholar, lecturer and consultant who has specialised in Chinese military, technological and intelligence issues for four decades.

Mr Sawyer is also the author of many books, including The Tao of Deception: Unorthodox Warfare in Historic and Modern China (Basic Books, 2007).

Speaking to Business Line on such vulnerabilities, Mr Sawyer said that Mississippi effectively divides the US and severing it would have staggering effects.

“However, similar vulnerabilities exist in most countries. Consider, for example, the Rhine – particularly where the bridges are a few decades or more older and the rivers have significant traffic, such as barges carrying volatile materials (again the Rhine, St Lawrence, Danube, etc).”

According to him, in the past decade, even relatively new, “supposedly impregnable” bridges have collapsed after collisions with ordinary barges and small freighters in the southern part of the US.

“At least a couple of highway bridges have been destroyed by the intense heat caused by tanker trucks that overturned and burned. To me, vulnerability is great everywhere, given the deteriorating condition of dams and bridges throughout the world.”

In a paper titled ‘Chinese Strategic Power: Myths, Intent, and Projections’, published by the University of Calgary’s ‘Journal of Military and Strategic Studies’, Mr Sawyer touches upon the history of aquatic warfare in China and draws a parallel to the US.

“Even though raised river beds are rarely found in North America, the potential for mounting aquatic attacks by destroying riverside levees still exists. Numerous dams can also be breached, particularly in regions like New England, where many were hastily constructed from earth or timbers more than a century ago and have long been neglected.”

Aquatic attacks

According to him, aquatic attacks rank foremost in effectiveness as can be seen in historical examples and the pervasive impact of flooding on New Orleans, encompassing severe damage to infrastructure, contamination and destruction of buildings, shattering of the electricity grid, death and displacement of inhabitants, unemployment and rampant social unrest.

“However, achieving such dramatic effects generally lies beyond the ability of low-level agents, though they might be able to disable a pumping system, tamper with controls to open sluice gates or mount other actions that have disproportionately great effect.”

Stating that the power of flowing water may also be exploited by converting assets already found on rivers such as the Mississippi, St Lawrence and the Rhine into kinetic and incendiary weapons, he said that reasonably strong currents will ensure that any vessel released upstream will be carried along until it collides with random obstacles or pre-chosen targets with considerable momentum.

A number of vessels can thus be directed against vital targets such as levees, bridge abutments, piers and loading facilities.

“Employed in co-ordinated fashion, they can achieve much greater strategic objectives, such as severing the finite number of rail and road bridges over the Mississippi river, thereby catastrophically disrupting the transport of industrial goods and agricultural products between the eastern and western parts of the US, as well as between the north and south (because the river would be blocked by collapsed bridges).”

Pointing out that the third well-developed form of aquatic attack typically targets essential water supplies, Mr Sawyer said that this most devastating and widely practised technique involves denying a locale’s supplies by blocking the source, damaging or severing the conduits or diverting the flow.

“This might easily be accomplished in many older North American cities because the systems often incorporate antique, highly fragile cast iron pipes, badly weakened valves and inadequate or no redundancy.”

He added that many also depend on a variety of aqueducts and oversized pipes to carry water for dozens, if not hundreds, of miles, “and are therefore easily targeted in remote areas. Given their high flow volumes, an easily accomplished minor breach would quickly produce massive collapse and the probable erosion of nearby terrain, requiring a lengthy period to repair.”

Citing the example of New York City, he said that it is well known that the city gets water supply from just two ancient aqueducts that run for miles above ground outside the city limits.

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