蜜芽传媒

The different stages of a river and how rainfall in the Mourne Mountains in Northern Ireland travels to Belfast. A river has three stages - upper, middle and lower. Rain falling in highland areas flows downwards to form a stream. This then travels downhill joining other streams. The point at which all the tributaries join the river is called a confluence. Steep sided mountains and heavy rains make the Mourne Mountains an ideal place to store rainfall. Water from this catchment area supplies Greater Belfast, which is thirty miles to the north.