Chesapeake Bay Sediment Building Up Behind Conowingo Dam
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BALTIMORE (WJZ)– The millions of tons of sediment washed into the Bay by Tropical Storm Lee is still settling out.
Alex DeMetrick reports that aftermath has triggered a search for a way to limit this type of problem in the future.
Much of the debris swept off the land by runoff from Tropical Storm Lee has returned to shore. But not the four million tons of sediment that spilled through the floodgates of Conowingo Dam.
“It’s a large volume of water that is essentially scouring a lot of that built-up sediment from that reservoir, and it’s dumping it into the Upper Bay,” Jenn Aiosa, a Chesapeake Bay Foundation scientist, said.
Sediment trapped behind the dam is building up.
“This is the top soil farmers don’t want to lose,” said John Page Williams of the Chesapeake Bay Foundation. “This is what’s come off construction sites. This is us. This is 21st-century human beings and all our activities.”
“About two-thirds of that is captured behind, settles behind Conowingo Dam,” Tom Parham of the Department of Natural Resources said. “How do we deal with that sediment? How do we prevent the Conowingo from filling up and then keep those excess sediments from flowing into the Bay?”
Maryland agencies and the Army Corps of Engineers are now looking for those answers. Because within 15 years, Conowingo’s reservoir will fill up with sediment.
“Too much sediment can definitely disrupt the living resources of the Bay,” said Aiosa.
Here’s how. Sediment first cuts off light to underwater grasses, and as it settles, can smother that growth along with bottom-dwellers like oysters. It also carries nutrients that feed algae blooms, which create dead zones.
“We want a clean and healthy bay,” Parham said. “We want to prevent these big pulses from coming down the Bay.”
The sediment study is jointly funded by the state and federal government, and will take three years to complete.