Why is the unsaturated zone not filled woth water

Answer:It is permeable and water flows through it.

Explanation:The unsaturated zone is also called as vedose zone. It is a zone that lies above the ground water table. It includes the subsurface layers of soil. The soil and rocks present in this region consists of pores, which allows the water from the surface of soil, being absorbed and seep underground due to the effect of gravity and hence, forms a groundwater reservoir or saturated zone. Hence, this can be said that unsaturated zone is not filled by water because it is permeable and water flows through it.