How Does the River Tees Change from Source to Mouth?

How does the River Tees change from source to mouth? [30 marks]

The River Tees is located in Northern England and travels 120km from its source in Cross Fell (700 metres above sea level) to its mouth in the Northern Sea. The river is broken down into the upper, middle and lower courses, all of which have different types of environments and land use due the variety of erosion, transportation and depositional processes.

The upper course of the river has a steep-sided V shaped valley with a narrow channel and interlocking spurs. Material in this section of the river is transported by traction; the rocks are large and jagged due to not having travelled far meaning little erosion has taken place.   There is more erosion than deposition due to rocks being heavy, causing them to be dragged along the river bed rather than dropped at the side. This erosion is vertical because of the downward pull of gravity which also causes a high velocity for the river. The majority of the landscape is moorland, still very high up and therefore difficult to use for crop growing, however it does not prevent farmers using for sheep. The land has also been used to store water at Cow Green Reservoir for the villages further down the river and a quarry built for building roads, using the whinstone grit which is an igneous rock. The geology of the upper course includes two layers of rock, whinstone which is hard rock and below this is milstone grit, a soft rock. This means that a waterfall (High Force) has been formed, as water has eroded and undercut the weaker soft rock. The waterfall retreats when the hard rock above collapses, it then moves upstream and a gorge is formed.

In the middle course the land is slightly flatter, less gravitational pull on the water causes it to move slower and therefore less erosion takes place vertically. This means some of the waters energy is used laterally, widening the river. The landscape is also slightly drier; this means it can be used for...