Two rivers joining is traditionally read as two lives, ideas or paths becoming one. Dream books see it as union and partnership, and as the turbulence that comes when currents merge.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.