At approximately the same time that the black flies descended, the river narrowed.

It crossed the Send at a point where the river narrowed, bent due south, and passed in front of the city.

The river narrowed and twisted up ahead, boiling with white foam.

The river had narrowed here; the near bank was no more than ten feet away.

At the end of the second pool, the river narrows.

The river has since narrowed over the course of time.

The river suddenly narrowed considerably, and the water speed doubled.

Immediately the river narrowed until it was no more than fifty feet across.

The river narrowed to less than fifteen feet, widening again beyond.

Thick clumps of trees stood a short way up ahead where the river narrowed.