'Marshes' in the Bible

“I will also make Babylon a possession of the hedgehog and of swamps of water, and I will sweep it away with the broom of destruction,” declares the Lord of hosts.

And that the fords [across the Euphrates] have been blocked and [the ferries] seized,And they have set the [great] marshes on fire,And the men of war are terrified.

But its swamps and marshes will not become fresh [and wholesome for animal life]; they will [as the river subsides] be left encrusted with salt.