I did find this...
From the Times-Picayune
Seems like a combination of things. I wish I was more familiar with the flow patterns of the area. I've been looking at maps for a week, and I still can't figure out which way all the water is supposed to go.
My understanding of the SELA project, at least from the map on the site you linked to, is that it was designed to pump water out of the New Orleans basin into the lake from a major rainfall. I didn't see how it could be used to prevent the flooding from a breach, although more pumps in place could possibly be of use now to drain the basin after the breaches were sealed.