A footing foundation for a water tower carries a load of 9000 kN and is 3.6 metres square. It rests on dense sand of 9 m thickness overlying a clay layer of 3 metres depth. The clay layer overlies hard rock. Liquid limit of clay is 54%, water content 40.5%, and grain specific gravity is 2.70. The saturated unit weight of dense sand is 18.9 kN/m3. Estimate the ultimate settlement due to consolidation of the clay layer, suppose the site to be flooded.