backwater

A backwater is still water off the main current — or a place where nothing ever happens. The same idea twice.

The literal sense belongs to rivers, where a backwater is a quiet pool out of the flow, and it is often the richest part for wildlife. The figurative sense is a mild insult about a town, an industry or a department that the world has passed by, so calling somewhere a rural backwater is not a compliment. Both share the picture of water that has stopped moving while everything else went on.