The meaning would be "at the place where the river turns back."

The river was turning red in the sun, with the blood of the wounded and dying.

A deep river came from the east, turned south to where it was joined by another from the west.

With the light gone, the river turned an inky black.

Even further north, the river turns northeast and enters Russia.

Then the river briefly turns west along a forest area.

The river turned and the sea was no longer in sight.

The river then turned south and continued in that direction for more than a hundred kilometers.

Just below the city the river turned to the right, and almost immediately the cliffs shut off our view of both cities.

The river then turns southeast again for another 8.7 km.