From the National Weather Service:
928 PM CDT MON APR 14 2008
THE FLOOD WARNING CONTINUES FOR THE MISSISSIPPI RIVER AT NATCHEZ
* UNTIL FURTHER NOTICE.
* AT 8:00 PM MONDAY THE STAGE WAS 55.6 FEET.
* MODERATE FLOODING IS OCCURRING AND MODERATE FLOODING IS FORECAST.
* FLOOD STAGE IS 48 FEET.
* FORECAST...THE RIVER WILL CONTINUE RISING TO NEAR 56.5 FEET BY SUNDAY MORNING.
* IMPACT...AT 56 FEET...SOUTH OF NATCHEZ, BOURKE ROAD IS UNDERWATER. RESIDENTS WILL HAVE TO BOAT INTO THEIR HOMES.ALL HOMES IN THE TOWNSHIP OF FT. ADAMS ARE FLOODED.
* FLOOD HISTORY...THIS CREST COMPARES TO A PREVIOUS CREST OF 56.6 FEET ON MAY 13 1973.
edit: The NWS has raised the predicted flood crest to 57 feet. That's higher than 1973. Still less than 1927, the year that inspired Randy Newman's song Louisiana 1927. (It also inspired the Army Corps of Engineers to build the Bonnet Carre spillway, to let water out of the Mississippi before it flooded New Orleans.) /edit
The Old River Control Structure was nearly wrecked by the 1973 flood.
Meanwhile, the Bonnet Carre spillway, which lets water from the Mississippi into Lake Pontchartrain, has been partially opened, to keep the Mississippi near New Orleans from rising higher.