RIVERS

• River Tees- Upper course - hard impermeable rock, V shaped valley, High Force waterfall
• River Tees- Middle course - meanders due to lateral erosion, ox bow lake show where meanders have cut off, natural leeves created as flooding recedes
• River Tees- Lower course - large estuary with mudflats and sandbanks, natural leeves created as flooding recedes
• waterfall formation: 1- soft rock is worn away and undercut by splash back from the waterfall (hydraulic action)
• waterfall formation: 2- hard rock overhangs and collapses under gravity
• waterfall formation: 3- soft rock is eroded by boulders in plunge pool (abrasion)
• waterfall formation: 4- water retreats upstream creating a gourge
• interlocking spurs are formed due to: the river isnt powerful enough to cut through the spurs of land and chooses to flow around them
• meander features: the inside the water is slow, shallow and deposition occurs (friction and low velocity)
• meander features: lack f velocity leads to deposition on the inside of the bend
• meander features: a bend or curve in the river
• meander features: outside of the bend theres- fats flowing water, deepest point, steep bank, erosion occur due to high velocity
• meander features: on the outside of the bend after time the abrasion and hydraulic action undercut the bank overtime the bank collapses leading to a river cliff
• Ox-bow lake formation: 1- meander neck becomes closer together
• Ox-bow lake formation: 3- leaving a meander with a loop and a straight river channel
• Ox-bow lake formation: 2- meander become closer together due to deposition as they collide together
• a rivers profile shows the upper, middle and lower course
• a meander erodes the valley floor leaving an ox-bow lake
• upper course: landforms of erosion
• middle course: landforms of erosion and deposition
• lower course: landforms of deposition
• leeves: formed by repeated flooding of the river, when flooded the river dumps coarse material close to banks this process continues over time
• leeves 1- during a flood water flows over the banks and deposits silts
• leeves 2- in between floods slow moving river deposits silts on river bed
• leeves 3- with each flood leeves build up as well as the river bed
• floodplains: area around the river that is covered in times of flooding- very fertile land, good for agri
• estuaries: where the river meets the sea
• factors that affect flooding: HUMAN- urabanisation, building on floodplains creating more impermeable surfaces meaning water is reaching drain quicker
• factors that affect flooding: HUMAN- deforestation, vegetation cannot store water anymore or absorb it meaning the water reaches rivers quicker
• factors that affect flooding: HUMAN- agriculture, if land is ploughed up and down water flows quicker down to rivers
• factors that affect flooding: PHYSICAL- precipitation, torrential rainstorms lead to flash floods and river channel cannot hold the water
• factors that affect flooding: PHYSICAL- geology, impermeable rocks encourage water to flow overland and into rivers
• factors that affect flooding: PHYSICAL- steep slopes, mainly in upper course, encourage a rapid transfer of water towards river channels
• lag time- time delay between the peak rainfall and peak discharge
• peak rainfall- highest amount of rainfall
• shorter the lag time the higher risk of floods
• hard engineering: dams and reservoirs- built across river channel and river discharge is released reducing flood risks

  ad- reservoirs are popular with tourists, new jobs and habitats are created, hydroelectricity can be used

  dis- expensive to build, reservoir could leak
• hard engineering: channel straightening- cutting through meander to create a straight channel speeding water flow and can protect vulnerable locations from flooding

  ad- prevents banks from collapsing, new habitats are created

  dis- natural to river environment, expensive
• hard engineering: embankments- a raised riverbank allowing the channel to hold more water before flooding

  ad- protects valuable properties, more natural

  dis- risk of flooding if breached, high maintenance costs
• hard engineering: flood relief- man made river channel constructed to bypass urban areas

  ad- new habitats

  dis- expensive, takes up land