[ian2]

American confidence has fallen to a low ebb.

What is the conceptual metaphor of this linguistic metaphor (fall to a low ebb)? I know the relatively lower level conceptual metaphor is CONFIDENCE IS TIDE. But can you find an even higher level conceptual metaphor? To make it easy for you to answer, let me illustrate this system a little:

1. Linguistic metaphor: He was bursting with anger.
2. lower level conceptual metaphor: INTENSE ANGER PRODUCES PRESSURE ON THE CONTAINER.
3. higher level conceptual metaphor: EMOTIONS ARE FORCES.

What I need is the highest level conceptual metaphor for "fall to a low ebb".

Thanks a lot.