The Washington Post covered a story in Sunday’s paper on a solution to sewage overflow into local rivers. Workers are constructing a tunnel under Washington D.C., using a machine, “The Lady Bird,” to take up the soil. The end product will be a 13 mile long sewer tunnel, to prevent the flow of untreated sewage to the Potomac and Anacostia River, and to Rock Creek, which frequently occurs with the overburdened combined sewer system in the District.
This tunnel could do a lot to clean up the local rivers, and reduce the flow of polluted water into the Chesapeake Bay. The Post states that all the soil collected by the Lady Bird will be transported to a dumping site in Maryland. My question however, is what happens to all this excess soil? Is there risk of the soil reentering the watershed through runoff, and how much of a risk could this pose?