'River' in the Bible

I looked in the vision and it seemed that I was at the citadel of Susa, [the capital of Persia], which is in the province of Elam; and I looked in the vision and I saw myself by the Ulai Canal.

Then I raised my eyes and looked, and behold, there in front of the canal stood a [lone] ram (the Medo-Persian Empire) which had two horns. The two horns were high, but one (Persia) was higher than the other (Media), and the higher one came up last.

He came up to the ram that had the two horns, which I had seen standing in front of the canal, and charged at him in [the fury of] his power and wrath.

And I heard the voice of a man between the banks of the Ulai, which called out and said, “Gabriel, give this man (Daniel) an understanding of the vision.”

On the twenty-fourth day of the first month, as I was on the bank of the great river Hiddekel [which is the Tigris],

Then I, Daniel, looked, and behold, there stood two others, the one [angel] on this bank of the river and the other [angel] on that bank of the river.

And one said to the man dressed in linen, who was above the waters of the river, “How long will it be until the end of these wonders?”

And I heard the man dressed in linen, who was above the waters of the river, as he held up his right hand and his left hand toward heaven, and swore by Him who lives forever that it would be for a time, times, and a half a time (three and a half years); and as soon as they finish shattering and crushing the power of the holy people, all these things will be finished.