In this example, a rectangular column of water, in hydrostatic equilibrium, is confined between two vertical walls, picture6. The water column is 1.0 units wide and
2.0 units high. Gravity is acting downward with unit magnitude. At the beginning of the calculation, the right wall (dam) is removed and water is allowed to flow out along a dry horizontal floor. Experimental results for this problem have been reported [18] for the position vs time of the leading edge of the water as it flows to the right (picture7).