Backwater is water that’s stagnant and out of the current. It’s a still pool created by a dam or a curve in the river. If a small town is described as backwater, then not much happens or changes there.
The word backwater has been around since the 14th Century meaning “water behind a dam.” Now it refers to any flat water, not just the water behind a dam. Backwater can also describe a place or situation that seems stuck in a rut, unmoved by current events. Literally, backwater is water that’s away from the current; figuratively, backwater is a place that’s away from current events.