: a formal garden usually in a depression or with terraces around it.

What is the point of a sunken garden?

Sunken gardens help conserve or divert water, alleviating runoff and allowing water to soak into the ground. They also provide adequate cooling for plant roots. Since water runs down hill, sunken gardens are created to “catch” available moisture as water runs down the edges and onto the plants below.

Why is it called Sunken Garden?

II.

The Sunken Garden acquired its name due to its basin-shaped low-level formation that has the deepest point of 65 meters above sea level (contrary to university's height of over hundreds of meters above sea level).