Higher Hydrosphere The Upper Course Areas with steep gradients will have an increased velocity and so the potential for erosion is higher, especially vertical erosion. The river also has the ability at this point to transport and break up larger pieces of rock. The main type of erosion here is hydraulic action which is caused when water traps air into the river banks, forcing them to expand and crack. Abrasion will often occur on the river bed, often resulting in potholes. Erosion is highest under flood conditions. Past Question: Erosion, transportation and deposition change down the river – choose one of these processes then describe and explain this change? Georesource.co.uk

Higher Hydrosphere Middle course The main areas of erosion will occur on the outside bends of the river through hydraulic action and abrasion (load being knocked against the bank and bed of the river and wearing it away). The main direction of the erosion is lateral. Lower course Erosion at this point is minimal but may be found in meanders. Georesource.co.uk

Higher Hydrosphere The Upper Course[Date] Today I will: - Know the formation of a waterfall Georesource.co.uk

Higher Hydrosphere Characteristics of the Upper Course - River channel is rocky. - Covered with various shapes and sizes of boulder. - Discharge is low. - Under flood conditions rivers energy is expended on ‘vertical erosion’ with hydraulic action and corrosion processes at work. -Valley sides are steep and form a ‘V’ shaped cross section. -Interlocking spurs. Georesource.co.uk

Higher Hydrosphere V- Shaped Valley Georesource.co.uk

Higher Hydrosphere The tallest waterfall in the world is Angel Falls in Venezuela which drops 979m. Niagara Falls, on the other hand, is only 51m high! Georesource.co.uk

Higher Hydrosphere Largest Waterfall in the UK – High Force in England. Georesource.co.uk

Higher Hydrosphere When waterfalls retreat they leave behind a gorge. Georesource.co.uk