riverbed
river bottom

The river bottom will also provide clues about the current.

A bolt of power struck from his staff down through the water toward the river bottom.

"I have moved to the river bottom," said the ship.

The river bottom was farther down each time her feet sought it.

We'll materialize on the river bottom, which at no point is more than 15 feet deep.

Father was spending his days digging for water in the river bottom.

Your typical get together would be in a Barn, field, or at the river bottom.

The whole river bottom in this area is about 10 feet thick with logs.

Over 100 species of birds are regularly seen each year along the river bottom.

He could feel his feet slipping in the river bottom.