Regarding the Sept. 6 editorial “ Progress is in the pipeline ”:

The Shenandoah Valley is underpinned by a porous, unstable karst formation. Dominion’s engineers, who will oversee the construction of a 550-mile pipeline through Virginia, West Virginia and North Carolina, originally said it would work around karst formations through the valley because the karst is too fragile. Now Dominion is planning to lay the pipe 10 feet down with plenty of cushion between it and the karst. This is nonsense. Sinkholes in the valley are frequent and have already caused ruptures in pipelines. Karst changes constantly, so it is impossible for scientists and engineers to predict where and when a rupture might open. Just laying pipe is likely to destabilize the formations below. No pipeline will stay intact if a large sinkhole opens under it.

Dominion cannot effectively police a pipeline this long through such varied terrain and prevent these leaks. The valley is the watershed for the Chesapeake Bay and for the District’s drinking water.

Alan Baragona, Staunton, Va.