Meanders
MORE INFORMATION


Wandering Rivers

When water flows across flat land it turns one way and then another - each bend is called a meander.
A meandering river constantly changes its course as the meanders move, often creating a wide floodplain filled with the remains of old meanders - old river bends, dried up or left as small ponds and lakes.

River with many meanders River meanders, with the traces of
older meanders in the fields

The word 'meander' comes from the name of a river in Turkey, known to the Ancient Greeks as the 'Maeander'. It was famous for its very winding course, bending back and forth, and the word came to mean anything complicated or winding, as well as the name of the river feature.

 

Map of river known to Ancient Greeks as the River Maeander


Meanders on the River Dee - proof that meanders move!
This photo and map show meanders on the River Dee near Farndon. On the map, the black dashed & crossed line  is the border between England and Wales.
Move your mouse onto the photo to show the border between England and Wales.

Look at the map and photo. Can you see that the border mainly follows the course of the river, but that in several places it follows a different route? This is proof that the river meander has moved in the past, AFTER the border was drawn.

Look at the photo - move your mouse on and off it to show, then hide, the border.  Can you see traces of an old meander in the fields, beneath the border line?
View of the old meander, in the fields to the right of the river.
Move your mouse onto the photo to show where it is.


How do meanders form?
Scientists think meanders may start to grow for lots of different reasons - it is quite complicated!
However, once they have started to grow, the meanders grow larger and move because:
  1. the river bank on the outside of the bend is eaten away (eroded) by fast flowing water
  2. the river bank on the inside of the band grows as silt, mud and other material is dropped (deposited) by the slower flowing water there
Click picture to see an animation of how meanders develop This video of a model river, speeded up, shows how meanders grow even when a channel was straight to begin with.

Model Rivers
Rivers can be studied by using small-scale models called stream tables - these can be very expensive, but look like a lot of fun to use! The videos below show how a stream table works (with a funny Lego disaster movie, too!).
Videos: Brigham Young University, USA

Sources:
Cool Geography
CLEO (Cumbria & Lancashire Education Online)
Wikipedia