As an unprecedented amount of floodwater makes its way down the Mississippi River, the U.S. Army Corps of Engineers opened the Bonnet Carre Spillway at New Orleans for the second time this year.
Corps officials try to limit spillway openings to minimize the impact of invasive freshwater species entering Lake Pontchartrain, as one of those impacts could be harming marine life. St. Bernard Parish President Guy McInnis says they have documented 26 dolphin deaths in the past two months, and most of the animals had freshwater lesions. Though Louisiana Wildlife and Fisheries officials have not made a direct link to the influx of fresh river water, officials in coastal Mississippi have after conducting a number of dolphin necropsies.
For oystermen, the opening of the spillway is always a cause for concern because it leads to plummeting water salinity levels as the freshwater suddenly dilutes the estuary’s brackish waters, which can kill the oysters they harvest.