Heavy Rainfalls Pose Risk to Bay Restoration

Bay Journal article (2018-10-04) reported that while the effects of Hurricane Florence will be fairly minimal on Chesapeake Bay restoration efforts, the well above average rainfall this spring and summer could pose challenges. According to the article, Maryland and Pennsylvania set records for the amounts of precipitation that has fallen this year.

The unusual rainfall has resulted in swollen streams and rivers, including the Susquehanna River and the Conowingo Dam, feeding large amounts of fresh water, sediment, and trash into the Bay. These factors can affected oxygen levels, grasses, aquatic life, and water quality in the Bay.

The article noted low-oxygen conditions were worse than average in June and had reverted to near normal levels in August. However, trash and debris, which creates water and shore litter, navigation hazards, and water contamination issues, has been extremely high. Significant amounts of trash were released into the Bay when the Conowingo Dam opens its floodgates (something it has had to do more frequently than normal due to the high rainfall).  The dam’s owner, Exelon, does remove some of the debris that is trapped behind the dam’s reservoir. From the article:

Exelon employees have removed 1,800 tons of floating debris at the dam so far this year, three times what they take out in a normal year, according to Exelon spokeswoman Lacey Dean.

Bay grasses are also at risk due to the heavy amount of smothering sediment that has been released into the Bay. From the article:

Grass beds appear to be holding their own in Virginia’s Rappahannock River and have actually expanded in the upper Chester River in Maryland, [Virginia Institute of Marine Science researcher Bob Orth] said. They have expanded as well in the upper Patuxent River, Orth added, but a large bed off Solomons Island in the lower part of the river has disappeared.

The article noted that the full effect on Bay grasses will not be known until next year, when some grasses emerge from their winter “hibernation.” In the short term, some beds that were recently re-established or saw growth appear to be surviving, albeit at a reduced size.