The $14\mathrm{.}9$ m high wall shown retains water at the same height as the wall. The top of the wall is supported such that no horizontal movement occurs at that point while the base is fixed supported at the bottom. Assume unit weight of water to be $9\mathrm{.}81$ kN$/$m$3.$ Assume that the width of the wall is $1$m$.$ Calculate the magnitude of the moment reaction at the base of the wall in kN$-$m