When the Conowingo Dam opened to fanfare nearly a century ago, the massive wall of concrete and steel began its job of harnessing water power in northern Maryland. It also quietly provided a side benefit: trapping sediment and silt before it could flow miles downstream and pollute the Chesapeake Bay, the nation’s largest estuary.Do you see the problem here?
The old hydroelectric dam spanning the lower Susquehanna River is still producing power, but its days of effectively trapping sediment in a 14-mile (22.5-kilometer) long reservoir behind its walls are over. Behind the 94-foot (29-meter) high barrier lies a massive inventory of coal-black muck — some 200 million tons (181 million metric tons) of pollutants picked up over decades from farmlands, industrial zones and towns.
How big a threat this sediment stockpile poses to the Chesapeake Bay or whether anything can even be done about it depends on who one talks to. With Maryland pushing to curb pollution in dam discharges, the issue has become a political football as Conowingo’s operator seeks to renew its federal license to operate the dam for 46 more years after its old license expired.
And as negotiations drag on, the lack of agreement about curbing runoff pollutants following the wettest year on record imperils hard-won gains in restoring the Chesapeake Bay. . .
The so called "Dead Zone" in the Chesapeake Bay is the bottom water in the deep channel that runs out of oxygen in summer, forming a hypoxic (with less than 2 ppm oxygen), or in some cases anoxic (without oxygen) zone in the water that is deadly to organism. I reported on that last night; good news that it wasn't, at time they checked, as bad as they feared it would be based on the amount of rain we have had.
The 200 million tons that AP reports in the "Dead Zone" are the sediments safely, for now, captured behind Conowingo Dam. A pain, but not a current problem. The problem is that Conowingo pool is full, and is no longer catching new sediment that comes down. Those are a problem, but not 200 million tons worth.
We have no idea how many pounds of "pollutants" there are in the Bay; that rather depends on the definition. Certainly nutrients, mainly fixed nitrogen and phosphorus, are regarded as the primary problem. But they do not constitute 200 million tons. The annualized TMDL for nitrogen in the Bay is only 186 million pounds, phosphorus 12.6 million lbs. Even the TMDL for sediment is only 3.2 million tons.
They have part of the story right, and part dead wrong: Behold the Gell-Mann Amnesia Effect:
Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray's case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward — reversing cause and effect. I call these the "wet streets cause rain" stories. Paper's full of them.
In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.