Damning the dam [Editorial]

The general election is still more than two months away but here's a bit of friendly advice to candidates hoping to win office in Maryland: Don't use the Conowingo Dam as an excuse to stop cleaning up the Chesapeake Bay. That would seem like common sense but it's become increasingly clear that damning the dam has become a popular political strategy.

Republican gubernatorial candidate Larry Hogan released a 30-second ad through his website last month that essentially blames the Conowingo for the bay's woes and urges voters to fight back against other pollution-fighting strategies endorsed by the U.S. Environmental Protection Agency and the Democratically-controlled state government. "We've got to get other states to pay their fair share," Mr. Hogan intones. "We've got to be tough, we've got to stand up for Marylanders."


There's a kernel of truth in that message but only a small one. There are serious issues involving the Conowingo and pollution coming from New York and Pennsylvania. But they should not be used as an excuse for dialing back Maryland's own efforts to improve water quality and reduce nutrients, sediments and other harmful pollutants flowing into the Chesapeake, much of it running off land — from farm fields to city streets — when it rains. Doing less in a state that benefits directly from the Chesapeake is unlikely to inspire states that don't even border it to do more.

Here's the issue with the Conowingo, the dam built in 1928 on the Susquehanna River to harness hydroelectric power: For decades, the dam has trapped nutrient-rich silt that might otherwise have flowed into the bay, but the dam's ability to continue to do so has been greatly diminished because so much has built up there. Increasingly, such pollution flows past the dam in heavy rains in what experts call a scouring event — picking up extra pollution from the enormous quantity already trapped at the dam and stirred up by strong currents.


What is the solution? The U.S. Army Corps of Engineers has estimated that dredging sediment behind Conowingo might cost anywhere from $50 million to $250 million annually and even then might not reduce pollution by much. Why? Because scouring accounts for a minor percentage, perhaps 20 percent in a big storm like Sandy, according to the Corps. The real issue is preventing pollution from running off land in Pennsylvania and New York in the first place.

That doesn't mean Maryland shouldn't seek potential remedies to Conowingo sediment — particularly now as Exelon, the dam's owner, seeks to renew its license to operate it — but that the main focus should be on reducing pollution more broadly. That's where the EPA and the multi-state Chesapeake Bay "pollution diet" come in. What's needed is for all states in the watershed to have their proverbial feet held to the fire and cut pollution from a variety of sources whether it means financing projects that lessen the impact of stormwater runoff or upgrading sewage treatment plants or whatever strategy is most appropriate.

Here's another point. Whatever happens at Conowingo is going to have little impact upriver in places like the Choptank, Severn or Potomac rivers, where pollution comes from local sources, not from the Susquehanna. Exelon could dredge until they had a 200-foot hole in the ground but it won't restore a single tributary. Indeed, it's worth noting that if there was no dam there at all, pollution would simply flow downstream unimpeded.

Critics throw around a lot of numbers to show that a large percentage of nutrients come from the Susquehanna but that's bound to be true no matter what as the Susquehanna accounts for nearly 50 percent of the freshwater flowing into the Chesapeake. No matter what pollution curbs are adopted, it's going to be the leading source of pollution because it's the leading source of water.

That doesn't mean what happens at the dam is unimportant but it's a complicated issue that requires context and a little bit of fact-checking. The muddy brown water that gets stirred up there in a major storm is unsightly and destructive, but it's not the biggest threat to the bay. And it's being used as an artificial issue by the same crowd that disparages efforts to clean up storm water pollution as a "rain tax." How convenient to blame pollution on a privately-owned dam instead of looking at one's own backyard.

The bottom line is that all states must be held accountable for water pollution, just as all individuals, businesses and governments in the watershed need to be accountable, too. Maryland doesn't achieve that end if it elects leaders who would withdraw support from programs vital to restoring the Chesapeake Bay.

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