Any number of problems are blamed on dams: flooding when they fail, downstream sedimentation when they’re removed, disruption of habitat and fish passage when they simply exist. Recently in the Chesapeake Bay region, officials are blaming one particular dam, and those who control its floodgates, for a trash problem.
Heavy rains several weeks ago led officials to open floodgates in Maryland’s Conowingo Dam—letting water flow downstream into the Susquehanna River and toward the Chesapeake Bay, along with a tremendous amount of trash that had built up behind the dam. Tires, Styrofoam, plastic bottles, and other manmade debris, as well as sediment and greenwaste, have poured into the bay in such quantity that it not only threatens to harm the shellfish and fishing industries, but also, Maryland officials say, endangers boats.
The floodgates have not been opened to such an extent in at least seven years, and an estimated 2 millions tons of sediment that had accumulated behind the dam—the amount that would normally make its way downriver over the course of a full year—arrived at the bay in just a few days.
At the beginning of August, Maryland Governor Larry Hogan called for Pennsylvania and New York to help clean up the mess. “The upstream states… need to take responsibility for their sediment and their debris that is pouring into our bay,” he is quoted as saying in this New York Times article. Ben Grumbles, secretary of Maryland’s Department of the Environment, agreed, saying, “From our perspective, polluters should pay.”
Predictably, though, their counterparts in Pennsylvania and New York disagree, and no clear legal responsibility for the pollutants exists in a case like this. Maryland has also suggested that the company that operates the dam should bear some of the responsibility for the cleanup. Meanwhile, climatologists believe that larger storms and extreme rainfall of the kind that triggered the flooding and caused the floodgates to be opened in the first place will become more common.
All the states in the Chesapeake Bay watershed have some responsibility for the ongoing cleanup of the bay; each state has annual targets for pollutants like nitrogen, phosphorus, and sediment. Several of the states—including all three involved in the current dispute—missed their targets for at least some pollutants in 2017.