How many major drainage basin are there in England and Wales?
11
What is the watershed?
The edge of highland surrounding a drainage basin.
What is a confluence?
The point where 2 rivers meet.
What is a source?
The starting point of a river, often led by a lake, spring, marchy.
What is a mouth?
The point where a river comes to an end.
What is a tributary?
Smaller rivers or steam that joins a larger river.