And I Think It's Going to Rain Today, Too

Rainstorm bearing down on us this afternoon

Too late, really, it already did: WaPo: Surge of storm water and pollution through the Conowingo Dam has scientists worried

A surge of storm water and pollution from Pennsylvania and New York was flowing into the Chesapeake Bay through the Conowingo Dam again last week, raising concerns that the relentlessly rainy summer could threaten oyster reproduction and throw off bay ecology for some time.

Even as scientists were assessing the environmental impact from recent storms, rising Susquehanna River waters were prompting dam operator Exelon Corp. to open Conowingo floodgates for the second time in three weeks, sending a deluge of muddy brown water into the upper Chesapeake.

“The water right now really looks like chocolate milk,” said Cindy Palinkas, an associate professor at the University of Maryland Center for Environmental Science. “I’ve never seen that before.”

Then she hasn't been around that much.

Palinkas led a research trip last week to a large bed of grasses at the mouth of the Susquehanna. Scientists were already concerned about the impact the record July rainfall could have on oysters, which need salty water to reproduce successfully. And they still have questions about the long-term effects of an influx of nutrient pollution and plastics that the floodwaters carried.

Zebra Swallowtail puddling on the beach

Now, the bay is facing another round of stress.

“It’s the event that doesn’t go away. It keeps unfolding,” said Doug Myers, Maryland senior scientist for the Chesapeake Bay Foundation.

Exelon officials expected to open 10 to 13 of the Conowingo’s 52 gates Thursday, about half as many as they opened during late July flooding.

The company has been the target of criticism from Gov. Larry Hogan, whose administration has demanded that it do more to prevent pollution from getting past the dam. Exelon responded by suing the state, saying it should not be held responsible for pollution it doesn’t create.

But they made the mistake of buy the asset that protects the Bay. I mean, used to protect the Bay.

Hogan said that he recently had “a pretty direct discussion with the chairman of Exelon” and that he plans to continue to press the company to help in Chesapeake cleanup efforts. He said the state will meanwhile solicit proposals within the next month for a test project to dredge sediment and nutrients that have built up behind the dam.

The nonstop rain and flooding are only making the problem worse, said Mark Belton, Hogan’s secretary of natural resources.
“We have been watching very closely the flow of the Conowingo Dam . . . to understand the nutrients that are coming over and to understand what type of debris might be coming over,” he said. “That’s really gunked up the bay.”

It could still be weeks or months before the repercussions of all the storms become clear in the Chesapeake. Scientists worry that large amounts of nitrogen and phosphorus washed into waterways could fuel algae blooms that could eventually strip portions of the bay of oxygen. Large amounts of sediment could smother plants and shellfish and block sunlight.

But they aren’t seeing their worst fears yet — in fact, for now, the rains have cleared the bay of a lot of algae, Myers said. “The entire bay has been flushed of some of the normal harmful algae species that might bloom in the summertime,” he said.

That surge of fresh water is not good for all creatures in the bay, though. Oysters need warm, salty water to spawn larvae that end up attaching to reefs, becoming what are known as spat. But all the rain has prevented ocean water from making its way into the middle and upper portions of the bay.

Myers said bay foundation scientists aren’t seeing signs of the next generation of oysters anywhere in the middle and upper portions of the bay. Water near Annapolis is almost fresh enough to drink, he joked, but if it doesn’t become saltier before fall, that could be devastating for oysters.

“If it gets cool before it gets salty again, then they may not reproduce this year,” he said.

In the northernmost reaches of the Chesapeake, if waters stay too fresh for too long, it could kill some adult oysters, said Michael Roman, director of the University of Maryland center’s Horn Point Laboratory. But the species is resilient.

“They’re adapted to these conditions,” Roman said. “It is rare to have this much fresh water coming in in July like we’ve had, but I’m sure it’s happened before.”