2. - Rivers begin in upland areas and flow downhill. The point at which the river starts is called the source . - On the river's course other smaller rivers called tributaries join with the main river. The joining points are called confluences . - The water in rivers and tributaries is obtained by the surrounding land. This area is called the drainage basin . The boundary of this area is the watershed . - This is part of the Hydrological Cycle .
32. As the valley widens downstream, the river starts to meander, as seen above. As it comes to the estuary, wide mud flats form, that are important wildlife areas for migratory birds and seals. p42
33. The lower course of the river tends to be much more urbanised. Factories and towns form in the lower plains near the estuaries, from which arises the need for management, due to flooding. Reservoirs are made. Light green = 0 - 60 metres Green = 61 - 120 metres Yellow = 121 - 300 metres Light Brown = 301 - 600 metres Brown = over 600 metres p42
