Crews are breaching a levee stressed by Isaac's floodwaters in southeast Louisiana's hard-hit Plaquemines Parish.

At the same time, water at a dam farther north in Mississippi was released in an effort to prevent flooding there. Officials hope the Thursday breach in Plaquemines Parish will relieve pressure on the levee.

The sparsely populated area south of New Orleans is outside the federal levee system and has been plagued by flooding since Isaac sloshed ashore as a hurricane Tuesday evening and pushed water over an 18-mile levee. There have been evacuations and nearly 150 had to be rescued from flooding.

ISAAC DOWNGRADED TO TROPICAL DEPRESSION

The heavy rain from Isaac -- now a tropical depression -- has brought more flooding today to areas north and south of New Orleans -- though in the city itself, life is starting to return to normal, and there have even been bursts of sunshine.

The fortified levee system appeared to do the job in protecting New Orleans itself.

But one man who lives outside the city, and whose home was flooded, says he's frustrated that the government spent billions of dollars to protect New Orleans and Jefferson Parish -- sending the water elsewhere. David Newman says, "The water's got to go somewhere." He says it finds "the weakest link" -- and in this case, he says, his neighborhood was "ground zero."

He and his wife have lived in their subdivision since 1992 and never had water in their home from previous storms -- including Katrina.

More than a million homes and businesses -- most in Louisiana and some in Mississippi -- began the day without power because of the storm.

Isaac was downgraded because its top winds are below 39 miles an hour. It's on track to cross Arkansas and southern Missouri tomorrow, then moving farther inland before breaking up over the weekend.

(Copyright 2012 by The Associated Press. All Rights Reserved.)