Question

Heavy infiltration (due to excess irrigation) of 3 cm/d causes a perched water table to form above a low permeable, flow-restricting layer. The top of the restricting layer is at a depth of 2 m, it is 0.4 m thick, and it has a K_v of 0.01 m/day. The material above the restricting layer is a silt loam with a K_v of 0.12 m/day. Coarse sand and gravel occurs below the restricting layer. After flowing through the restricting layer, the water moves as unsaturated flow through the sand and gravel to an unconfined aquifer. Find height of the perched water table above the top of the restricting layer

Answer 1

Here is a picture to go along with this problem, the answer is L = 1.067m but I don't understand how that answer is achieved. Please help