Place a cutoff wall at the heel of the dam depicted in Figure P7 .8.4 much like Example 7 .18. The cutoff wall should extend downward one-third of the distance to the impervious layer. Estimate the seepage per unit meter width of dam. Assume the permeability is 4.45 × 10- 7 m/sec and the upstream water depth is 20 m. If the seepage per unit meter without the cutoff wall is 4.45 × 10-6 m3/sec per meter, what is the percent reduction in seepage using the cutoff wall?