Why not: "di mana bagian dangkal kolam itu?"
what's wrong with "di mana bagian dangkal kolam"
It needs a "yang" to define which part of the pool you are talking about and "kolam" should probably follow "bagian" as it should read the part (of the) pool that is deep... So "bagian kolam yang dangkal"?
Why is "Di mana bagian kolamnya yang dangkal?" (the pool) marked as being wrong?
The spelling of "Bagian" is wrong ;(