が深い

is deep

→ が
phrase Rare #25,046
is deep Used for a place or substance with considerable depth, such as a lake, river, or mud.
JA: この湖はここが深い。
EN: This lake is deep here.

そっちのほうは泥が深いからその先!

The mud is deep that way, so go past it!

— となりのトトロ (1988)

湖のこの場所が深い。

This part of the lake is deep.

川のこの部分は水深が深い。

The water is deep in this part of the river.

川はこの辺が深い。

The river is deep around here.

その湖はこの地点が深い。

The lake is deep at this point.