Suspected Sunni insurgents bombed and badly damaged a span over the main north-south highway leading from Baghdad on Tuesday — the third bridge attack in as many days in an apparent campaign against key transportation arteries.
The attack occurred 35 miles south of Baghdad and just six miles south of a bridge brought down on Sunday...
About 60% of the bridge was damaged, and cars could still pass over it via one lane, police said. But debris from the blast fell on the main north-south expressway below, further complicating efforts to reopen that main artery, closed after Sunday's blast dropped masses of concrete onto the roadway.
On Monday, a parked truck bomb destroyed a bridge carrying traffic over the Diyala River in Baqouba, 35 miles northeast of Baghdad. There were no casualties, but vehicles were being forced to detour to a road running through al-Qaeda-controlled territory to reach important nearby cities.....
Earlier this month, a bomb heavily damaged the Sarhat Bridge, a key crossing 90 miles north of the capital on a major road connecting Baghdad with Irbil, Sulaimaniya and other Kurdish cities.
In March and April, three of Baghdad's 13 bridges over the Tigris River were bombed. The attacks were blamed on Sunni insurgent or al-Qaeda attempts to divide the city's predominantly Shiite east bank from the mostly Sunni western side of the river.
It has long been a common belief that the Shi'ite militias have been winning the battles to control significant chunks of Baghdad's previously mixed neighborhoods, while at the same time, the Sunni Arabs insurgencies have controlled the access to Baghdad from the northeast, north, west, south and southeast. It is through the control of the logistics pipeline that the Sunni Arab guerrillas will be able to isolate the city and localized the strength of the Mahdi Army and the Badr Brigades. Baghdad can not function as a modern city with all of its road and air links to the outside world cut.
Each individual bridge attack is relatively insignificant as there are sufficient bridges to allow for re-routing with minimal marginal cost. However a systemic campaign on the same routes, even against the easier to replace highway overpasses, will begin to slow down the already restricted flow of commerce and supply into the city.
Tim F of Balloon Juice made an interesting analogy to me in an e-mail this morning on the functionality of cities and populations under stress:
In ecology they say that a population under tremendous stress can lose diversity well before it loses numbers, as the least stress-tolerant variations begin to die off first. Then, when the population has few evolutionary routes
left open to it, an orthogonal stressor can arrive and the end comes surprisingly fast.
My feeling is that the same could happen to us. Our convoys could keep rolling at the same rate as always, giving the impression that everything is fine. But come the day when we only have one bridge left over which we can roll, well...
The flow of supplies to Baghdad from the south and from other areas in Iraq may not be restricted as long as there is rapid reconstitution and reconstruction capacity. However the variety of goods, and the cost of shipments will continue to increase as the United States and any other major user of the Iraqi road network will continue to be funnelled into a narrower option space. The road network is transforming from a reasonably resiliant system to a narrower, and more brittle system with more single points of failure.