Parallel to Thebes (3:8-15)
Thebes was destroyed by the Assyrians in 663; Thebes was protected by water and
was a great city with vassal states (Nahum's parallels in 3:8,9). Yet as it
was captured, so too for Ninevah.
What's all this about a flood? (2:6)
From http://www.bible.org/page.asp?page_id=974 :
"According to the ancient historian, Diodorus Siculus, the armies laid siege
to the city for over two years. In the third year, the Khosr River, which
ran through the city flooded, broke down the floodgates and part of the
wall which allowed the enemy to come in. This fulfilled part of Nahum's
prophesy in 1:8; 2:6 and 3:13. (Diodorus Siculus tended to exaggerate - the
Babylonian chronicles say the siege lasted only a few months. The truth is
probably somewhere in between. But I think we can rely on the account of
the flood because Nahum predicted it.)"