(RT) Geology:

• The Upper Tees is mountainous and impermeable. This increases rates of surface runoff and allows more water to flow into the river increasing its erosive power vertically which creates steep V-shaped valleys.
• Through the middle and lower course of the Tees, the landscape is made up of sandstone, a softer rock. The river’s increasing volume and energy mean that there is lots of lateral erosion, widening the river channel and forming meanders.