Saltwater from Gulf continues threatening New Orleans water despite federal aid

Drought conditions enabled saltwater to infiltrate Mississippi River further upstream than usual.
Saltwater has already reached some parishes and contaminated drinking water supplies.
Federal emergency declared, authorizing FEMA relief efforts and resources.
Strategies to mitigate include barging freshwater, raising underwater barriers, and potential new pipeline.
Timeline predicts saltwater reaching New Orleans water intakes by late October if unabated.