The river that Ezekiel described flows through the desert to the sea.
Then said he unto me, These waters issue out toward the east country, and go down into the desert, and go into the sea: which being brought forth into the sea, the waters shall be healed.
The waters of the sea are healed by the river flowing into it. This must be the Dead Sea, as the waters flow towards the east. But the sea is metaphorical, as shown by the prophet Isaiah, when he wrote:
But the wicked are like the troubled sea, when it cannot rest, whose waters cast up mire and dirt.
John also showed that the sea is symbolic.
And he saith unto me, The waters which thou sawest, where the whore sitteth, are peoples, and multitudes, and nations, and tongues.
When John said, in Revelation 21:1, there is no more sea, perhaps he meant there are "no more wicked."
The fish in Ezekiel's prophecy are metaphorical, as when Jesus said to some of his disciples, who were fishermen, "I will make you fishers of men." [Mark 1:17; Luke 5:11]
Jesus explained what the waters of the river represent.
In the last day, that great day of the feast, Jesus stood and cried, saying, If any man thirst, let him come unto me, and drink. He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water. (But this spake he of the Spirit, which they that believe on him should receive: for the Holy Ghost was not yet given; because that Jesus was not yet glorified.)
The "living water" is the Spirit of God, that was given to the apostles, and the New Testament shows how the Spirit led them to an understanding of the prophecies of the OT.
According to the apostles, Christ's kingdom was set up when he ascended to heaven, and sent the Spirit to the early church. [Acts 2.36] That Spirit is the river foretold by Ezekiel, that flows through the desert to the sea, and heals it. The sea was a border of Israel, and so it probably represents the nations of the world, those who dwell beyond the promised land, who had not heard the gospel. The river comes from the temple, which is the church, not a building made with human hands. [Eph. 2:20-21]
But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building.
The church, which includes the saints of all ages, is the "greater and more perfect tabernacle." It is greater than the earthly temples in Jerusalem.
The desert through which the river flows, which becomes fruitful, I suggest, represents the scriptures. There are many prophecies about the desert being changed. Isaiah said, "the desert shall rejoice, and blossom as the rose." [Isaiah 35:1] And, "...in the wilderness shall waters break out, and streams in the desert." [Isaiah 35:6] And, "...I give waters in the wilderness, and rivers in the desert, to give drink to my people, my chosen." [Isaiah 43:20]
What else could this desert be? It is to the wilderness, that the woman flees, in Rev. 12:6 and 12:14. This is repeated twice in the same chapter, and on each occasion, it is for a specific period of time, called "1,260 days," and "a time, times and a half." This period is not a literal three years and a half; the period 1,260 days corresponds to Daniel's 1,290 days and 1,335 days; all different ways of expressing a symbolic "half-week" of three and a half years, but none of these numbers correspond to a literal three and a half years. And since different numbers are assigned to the period, it cannot be a literal three and a half years. But it could be a symbol representing the present age of the church, and the period during which Christ confirms his covenant with the saints and the gospel is preached. It is the last half-week of the 70 weeks of Daniel 9.
Each time she flees to the wilderness, the woman is "nourished" or "fed." The scriptures represent the "food" that has been provided by God for his church. When the OT prophecies are "watered" by the Spirit, that is represented by the spiritual river of Ezekiel 47, the "blossoming" of the desert is seen.
The mountains and hills probably represent revelations and promises of God, that were given to Israel. Several revelations were given during the period of the Exodus, and when the Israelites took possession of the land. Paul said all those events occurred "for our examples." [1 Corinthians 10:11] Some prophecies of the OT are only poorly understood, but if the land is represented by the revelations of God, and prophecies are represented by mountains, the scriptures indicate that the mountains will be a source of wine for the saints. The prophet Amos said:
Behold, the days come, saith the LORD, that the plowman shall overtake the reaper, and the treader of grapes him that soweth seed; and the mountains shall drop sweet wine, and all the hills shall melt."
What is the wine? Is it literal? Probably not. Perhaps it means the prophecies that mountains represent will be understood. Joel wrote a similar prophecy:
And it shall come to pass in that day, that the mountains shall drop down new wine, and the hills shall flow with milk, and all the rivers of Judah shall flow with waters, and a fountain shall come forth out of the house of the LORD, and shall water the valley of Shittim.
Joel said the stream from the temple waters the valley of Shittim, on the east of the Jordan, where the Israelites camped before entering the promised land. So the river can hardly be literal; neither are the mountains literal, or the wine and milk. But the apostle Peter associated milk with God's word.
1 Peter 2:2
As newborn babes, desire the sincere milk of the word, that ye may grow thereby.
Not only milk, but honey also is associated with the word of God. [Psalm 119:103] And Jesus used wine to represent the new testament. [Luke 22:20]