The Land and Its Water
A river from source to sea
Follow a river from its source to its mouth and name the parts of the journey — tributary, confluence, valley, delta and basin — and say what the river does to the land along the way.
Every river has the same story, whether it is a stream you can step across or the greatest river on the earth. It begins somewhere high, it flows downhill because water always does, and it ends somewhere low — usually in the sea. What changes along the way is what the river is doing to the land it runs through, and that is what makes the journey worth following from one end to the other.
The words for the journey
The source is where a river begins — a spring, a lake, or melting snow high in the mountains. A tributary is a smaller river or stream that joins a bigger one, and the place where two rivers meet is a confluence. The mouth is where the river ends and empties into the sea. And the basin is all the land whose rain and streams drain into that one river.
Near its source the land is steep, so the water rushes. A rushing river wears rock away — that is called erosion — and carries the pieces along with it, cutting a narrow valley as it goes. This is the stretch where waterfalls and rapids are common. Further down, the land flattens out and the river spreads and slows. Slow water cannot carry as much, so the river lets go of the mud and sand it has been holding on to, and drops it along the way. Dropping it is called deposition, and it is what makes the soil of a low plain so deep and so good to farm.
At the mouth, the river slows almost to a stop and drops nearly everything left. Over a long time that dropped mud builds new land, the river splits into several channels to get around it, and the whole fan-shaped stretch is called a delta. Not every river builds one: a river that meets the sea in a deep, wide, funnel-shaped mouth instead, with the tide running in and out of it, has an estuary. Which of the two a river ends in depends on how much it carries and on what the coast is like where it arrives.
Worked example
A stream begins at a spring on a hillside, is joined by another stream lower down, crosses a wide flat plain, and finally spreads into several channels at the coast. Name each part of that journey.
The spring on the hillside is the source.
High ground is where the water starts, because from there it can only go down — and going down is the one thing a river never stops doing.
Try it together
Follow a river from the hills to the coast, one stretch at a time.
Answer each step with a single word.
1.The river starts where snow melts high in the mountains. What is that starting place called?
Have a go
Have a go on your own. Two rivers meet and flow on as one. What is the place where they meet called?
Ready to practice?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.