tom pokrefke is chief of the river engineering branch and heads the red eye investigation. the problem that we're studying on the red eye crossing is the crossing itself. when you go from a low water situation to a high water situation, it tends to fill with sediment. where you go from high water to low water, there's not enough energy in the water to clear that crossing out and maintain the channel deep enough for ship-type navigation in that part of the river. basically, the red eye crossing area has been kept open in the past using dredging. when the water filled going from a low water situation to a high water situation, the engineers dredged the channel to make sure it was deep enough. the army corps of engineers would like to minimize the amount of dredging necessary to keep the channel clear. at the core of their study is a scale model of the river. graded, crushed coal is used to represent the bed material. by studying how the coal moves as water is discharged through the model, the corps' hope hope to better understand the red eye crossing problem and come up with