A sheet pile has an embedment depth of 12 m in a homogeneous soil stratum. The coefficient of permeability of the soil is 10^-6 m/s. The difference in the water levels between the two sides of the sheet pile is 4 m. The flow net is constructed with five number of flow lines and eleven number of equipotential lines. The quantity of seepage (in cm³/s per m, up to one decimal place) under the sheet pile is