what kind of problems are they seeing on the levies right now? reporter: nothing that the army corps of engineers didn t anticipate. they re seeing seepage underneath. they say that s normal and are taking care of it. some of them have been impacted by this flood, they re seeing what is called sand boils, where water goes through the earth underneath the levies and percolates up on the dry land and creates these areas where water is seeping up on the dry land. left unattended, that could erode away the base of the levy. but they say they re keeping it under control and will not be a threat to the levies. david mattingly, appreciate it. up next, rebels in libya. the opposition forces defending the city of misurata. they are still holding on, coming under heavy fire. it s a remarkable battle. plus, one of the world s biggest power couples splitting up.
we ve had minor stress on it in terms of sand boils and slidings, but ultimately, we ll go back out and do an assessment of this. my engineers are out there right now collectingthat information. explain to our viewers what you just said about sand boils. many of us who don t live along flood areas or rivers think the rivers will hold as long as they don t come over top of it. the real issue is the underpinning or the undergutting of the levee system. first off, we have no concern of any overtopping of levees or flood walls. i want to make sure that s clear. in terms of the under seepage on our levees, that is to be expected on this type of pressure and this type of environment. where we get most concerned is where the water comes underneath the levee and brings with it material. that s when we try to equalize the pressure on the land side of the levee.