What types of drainage basin are more likely to flood? ?

Question

please can you add a little explaination why? thnx

Answer 1

The flat drainage basins of older rivers are much more prone to flooding.

You have basically three parts or stages of a river: youthful, mature and old age. Youthful is near the source or the upper part of the river where the river is faster flowing and the valley is deep cut and V-shaped. Little flooding here.

The second second, maturity, is slower moving and the valley is much more rounded and is U-shaped. Again, little flooding here since the banks are still fairly high. In the third section, the river moves quite slowly. It meanders back and forth like the Mississippi. The river banks are very low resulting in large flood plains.  When several tributaries are joining an older river, water volume increase especially after downpours and heavy rains - good chance of flooding.

Some things that need to be taken into consideration are:

- size and shape of basin

- channel formation and roughness

- vegetation cover

- drainage density

- how permeable the basin is

- land use (agriculture, urbanization)

However, heavy rains in a low, flat river bed basin will always lead to flooding.