As fishermen deep in the Louisiana bayou, Kindra Arnesen and her family have faced their share of life-altering challenges in recent years.

First came Hurricane Katrina, the 2005 monster storm that devastated her small fishing community in Plaquemines Parish before roaring up the Gulf Coast, killing more than 1,800 people and destroying $125 billion in property. Five years later, BPs Deepwater Horizon drilling rig exploded 40 miles offshore, spewing nearly 200 million gallons of crude. The fisheries have not fully recovered more than nine years later, nor has her family.

But this year may be worse. A historic slow-moving flood of polluted Mississippi River water loaded with chemicals, pesticides and human waste from 31 states and two Canadian provinces is draining straight into the marshes and bayous of the Gulf of Mexico the nurseries of Arnesens fishing grounds upsetting the delicate balance of salinity and destroying the fragile ecosystem in the process. As the Gulf waters warm this summer, algae feed on the freshwater brew, smothering oxygen-starved marine life.

And as of Wednesday, an advancing storm looks likely to turn into a tropical storm or hurricane by the weekend, with the potential to bring torrential downpours and more freshwater flooding.