Geography GCSE

• The main types of renewable energy are solar, wind, hydroelectricity, geothermal, tidal, wave, biomass, and biofuels.
• Solar power is generated using photovoltaic cells or concentrated solar panels that convert sunlight into electricity.
• Geothermal energy uses heat stored within the Earth's crust to create steam, which drives turbines to generate electricity.
• Nigeria is a LIC that hires migrant workers from other countries (HICs) using TNCs because they are unable to afford resources to get oil themselves
• A floodplain is a wide, flat area of marshy land on either side of a river, and is found in the middle and lower courses.
• Floodplains are made of alluvium, a sediment deposited by a river when it floods.
• Floodplains are used for farming as the soils are very fertile.
• Meanders migrate across the floodplain due to lateral erosion.
• When meanders reach the edge of the floodplain they erode the valley side (bluff).
• This explains why floodplains are very wide.
• When the river floods it deposits silt, creating a very flat floodplain.
• Layer upon layer builds up over many years to form a thick deposit of fertile alluvium.
• A levee is a raised river bed (levé in French means 'rise') found alongside a river in its lower course.
• A ridge of sediment is deposited naturally to build up the levee.
• During low flow conditions deposition takes place, raising the river bed and reducing the capacity of the channel.
• When flooding occurs, water flows over the sides of the channel.
• The velocity of the river decreases rapidly leading to deposition of sediment on the river banks.
• First the coarser sands are deposited and then the finer silt and mud.
• Gradually after many floods the height of the banks can be raised by as much as two metres.
• In the UK most river mouths form wide tidal estuaries, especially in areas where sea levels have risen.
• Estuaries are transitional zones between river and coastal environments and are affected by wave action as well as river processes.
• The main process operating in estuaries is deposition.
• During a rising tide river water is unable to be discharged into the sea.
• The river's velocity falls and sediment is deposited.
• At low tide these fine deposits form extensive mudflats.
• Over time, mudflats develop into important natural habitats called saltmarshes.
• The upper course of a river is characterized by a steep sided V shaped valley.