The rainfall from Hurricane Barry on the Coast has delayed the closing of the Bonnet Carré Spillway.
In an effort to ease the flooding of the Mississippi River, the spillway has been open since late February, and the 168 open bays won’t close until the water level at the structure drops to 21 feet. While the rain from Barry delayed the closing slightly, Matt Roe, a Public Affairs Specialist with the Corps’ New Orleans District, said that the spillway is on track to close late next week.
When the closing process begins, Roe said that engineers will likely be able to close around 20 bays per day as they evaluate upstream and downstream conditions. Unexpected rainfall could also impact the number of bays that can be closed.
Since the opening of the spillway, the introduction of freshwater into the Mississippi Sound has decimated marine life off of the Mississippi Coast, including oyster, crab and shrimp populations.
In late May, Governor Phil Bryant wrote to Secretary of Commerce Wilbur Ross requesting a federal fisheries disaster declaration for Mississippi. In a recent update from the Department of Marine Resources, brown shrimp in state monitoring trawls was down more than 82% over the past four weeks compared to the prior 5-year average, and the oyster mortality on Mississippi harvest reefs was higher than 90% for all reefs except for Pass Marianne.
The NOAA has declared an ‘unusual mortality event’ for dolphins after more than 250 dolphins have been stranded since February 1, which is approximately three times higher than the average. Of the 260 dolphin deaths, 121 were in Mississippi.
Roe said that the daily discharge through the structure has dropped by over 60,000 cubic feet in recent weeks.