A meander is a bend in the river course. This is how they are formed: As water moves downstream and around a bend, it moves in a spiral fashion. It moves towards the outer bank of the curve at great velocity, eroding the bank. Much of the eroded material is then carried towards the opposite bank and is deposited there. Deposition takes place because friction between the water and river banks is great, reducing the velocity. The water then moves downstream towards the next bank in a spiral manner and the process is repeated.