A dry riverbed is the trace of a flow that has stopped, so tradition reads it as a source of energy or feeling that has run low. It also keeps the promise of water returning in another season.
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.