And Four Rivers
And Seven Oceans
And Water, Lots of Water
The Sea of Galilee and the Dead Sea are both fed by the Jordan River, separated by only 63 miles, yet these two "seas" couldn't be more different (technically, they're lakes). Galilee, also called Kinneret, Chinnereth, Gennesaret, or Tiberias, is full of life, including 35 species of fish - Sacred Places In the World . The Dead Sea is just that, dead. In Hebrew, it is known as the Salt Sea. It is so salty (35%) that nothing plant or animal lives in it.
One analogy likens water to the Holy Spirit - Bill Hogan , Rabbi Dov Greenberg . When the Spirit flows through us like the Jordan flows through the Sea of Galilee, life is produced in abundance. In other words, Jesus must flow through us, producing fruit like love, joy peace, etc. When one keeps the Spirit for themselves, perhaps through selfishness, greed, or fear, it becomes stagnant, not producing fruit. The Dead Sea would be the extreme example of this. This works equally well if you substitute the word Blessings for Holy Spirit. "Freely you have received, freely give".
Dead Sea Works
|Dead Sea Sinkhole|
Rivers Of Living Waters
So how well does the analogy hold? Are people in general or Christians in particular like the Jordan River producing a Sea of Galilee or a Dead Sea? Are these the only two choices? Remember most rivers empty into an ocean, but the Jordan is an Endorheic river, and a unique one at that. Remember there are other kinds of rivers, even in the oceans. One other possible interpretation that occurs to me is the power of living water. Christians normally associate the phrase living water with Jesus words in John 7.
37 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. 38 He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water.
But the term Living Water was in use long before.
Literally, the mikveh is identified as a collection of water, a pool of sorts, which has gathered by God’s design. That is to say, there was no human intervention, no one dug a hole, no one collected water in jars to fill the pool. This collection of waters might be a river or a sea. The water source came about as part of the Almighty’s plan, which gives it the nomenclature: Living Water.
The Mayim Chayim (Living Water) has some important spiritual qualities. According to the Torah, a source of Living Waters cannot be defiled. Mayim Chayim overcomes defilement, but defilement can never overcome Mayim Chayim. When something becomes defiled, or ritually unclean as defined by the Biblical standard, whether a person or an object, it must be immersed in Living Water to be declared “clean.” - Pneuma Review 
Living Water can not be defiled. Does that mean the water from the Jordan River that flows into the Dead Sea is still Living Water? Thousands of people depend on the Dead Sea for their living. Ironic, huh?
From a certain point of view, the spiritual analogy of the two seas makes sense. But it isn't the whole story. I don't know what analogies there might be for other types of rivers, I invite you to share your thoughts.