The average commuter in Lagos spends over 3 hours in traffic everyday ○ Makes Lagos one of the most congested cities in the world ● 40% of new cars in Nigeria are registered in Lagos → occupies just 1% of the country’s total area Problems caused by traffic congestion:...
Introduction: ● Located in Windsor-Eton area ● Relief channel for the River Thames was opened in 2002 ○ 11.7 km long, 50 m wide ○ Funded by Environmental Agency (EA) ○ UK’s largest artificial river but designed to look like natural river ○ Diverts water from the River...
Social challenges: ● Rapid growth has lead to numerous problems in Lagos ○ Planners have been unable to keep up with the rapidly expanding population ○ Over 60% of the population live in slums (eg/ Makoko) ■ Houses in Makoko are flimsy , wooden huts, built on stilts ■...
Squatter settlements = an area of poor-quality housing, lack of amenities ○ eg/ water supply, sewage and electricity ■ Also known as informal settlements/slums/shanty towns ● Often develop spontaneously and illegally in LICs ● Mainly found on marshy, poorly drained...
Only 10% of the city have a piped water supply that has been treated and purified ● Rest of population rely on water vendors/dig wells or sink boreholes to reach groundwater ○ Water in lagoon is not suitable for drinking → salty and polluted ● In 2012 → Lagos State...
Hard engineering = uses expensive heavy machinery to build artificial structures which work against nature to prevent flooding ● Dams and reservoirs ● Channel straightening ● Embankments ● Flood relief channels Dams and reservoirs: → Dam = large concrete barrier built...
Soft engineering = involved adapting to a river and learning to live with it → is cheaper , but often less effective than hard engineering ● Floodplain zoning ● Flood warnings/preparation ● Planting trees ● River restoration Floodplain zoning: → Floodplain zoning =...
Hydrograph = shows how a river’s discharge changes in response to a period of rainfall ○ Vertical axis = measures precipitation in mm , measures discharge in cm 3 /s ○ Horizontal axis = measures time in days/hours ○ Bars = represent rainfall ○ Line graph = represents...
Definitions: ● Precipitation = any form of moisture reaching the ground (eg/ snow, rain, sleet or hail) ● Interception = water being prevented from reaching surface by trees/grass ● Surface storage = water held on ground ( eg/ puddles) ● Infiltration = water sinking...
Infrastructure = basic equipment/structures needed for a country/region to function properly (man-made) ○ eg/ roads, water supply, sewage ● Greenfield sites = plot of land in rural/edge of an urban area that has never been developed on before ● Land use = what the...
Meanders: ● Meander = a bend in a river → formed by a combination of fluvial erosion and deposition → Characteristics: ● Inside bank: ○ Curved, beach-like features ○ Gentle, convex slope ○ Sediment consists of sand/gravel/pebbles ○ Vegetation grows furthest from water...
Levees: ● Levees = naturally raised river banks found on either or both sides of a river channel prone to flooding → Characteristics: ● Raised river banks (2 - 8 metres) ● Composed of gravel, stones and alluvium ● Coarsest sediment closest to river channel ●...
River Severn = travels 354 km to estuary in Bristol Channel Estuaries: ● Estuary = tidal part of a river where the channel broadens out as it reaches the sea ○ Freshwater from river merges with salt water from the sea ○ Affected by both fluvial and marine processes →...
Interlocking spurs: ● Interlocking spurs = projections of high land that alternate from either side of valley and project into the valley floor ○ Formed by fluvial erosion ○ Found in upper course → rocks are hard → Characteristics: ● Steep gradient ● Convex slopes ●...
Waterfalls: ● Waterfalls = water falls down a vertical drop in the channel over an area of hard rock followed by soft rock ○ Forms where there's a junction between a hard rock capping upstream, and soft rock downstream → Characteristics: ● Hard rock layer on top of...
→ CASE STUDY: Medmerry Conflicts between stakeholders: → A stakeholder is either an individual, group or organisation that are affected by the activity of a new development . In Medmerry the main stakeholders are: ● Local farmers ○ -ve → 3 farms had to be abandoned...
Fluvial (river) processes = processes relating to erosion, transport and deposition by a river → help shape the river’s channel and valley ● Fluvial erosion = process by which a river wears away the land → ability to erode depends on velocity Vertical/lateral erosion:...
Key words: ● Long profile = the gradient of a river as it journeys from the source to the mouth ● Cross-profile = a section taken sideways across a river channel/valley ● River channel = area occupied by the river/where the river flows ● River valley = overall shape...
Cross-profile = section taken sideways across a river channel and/or valley ○ Channel cross-profile = only includes the river ○ Valley cross-profile = includes channel, valley floor and slopes Cross-profile changes downstream: ● Upper course ○ Very narrow → only few...
Sand dune = large heap of sand that forms on the dry backshore of a sandy beach ● Succession = the change of species over time ● Zonation = the change of species over space ● Xerophyte = a plant adapted to living in a dry, arid habitat like a sand dune ● Embryo dune =...
Coastal realignment = creating an engineered new position of a coastline ● Managed retreat = when a decision is made to no longer follow a “hold the line” strategy for managing coastal flooding and erosion ○ People are moved out ○ Buildings are demolished ○ Breach is...
Why the scheme was needed: ● Medmerry (West Sussex) → largest managed coastal realignment scheme in Europe ○ Environment Agency (EA) considered area to the west of Selsey (West Sussex) to be at a high risk of flooding due to climate change ● Shingle ridge was the only...
Spits: ● Spit = an extended stretch of sand/shingle that projects out to sea and is joined to the mainland at one end ○ Form where the coastline suddenly changes shape /at the mouth of an estuary ○ Unstable landform → continues to grow until the water becomes too deep...
Beach = landform of coastal deposition that lies between high/low tide levels ○ Mostly formed of sand/shingle/pebbles ○ Beach that forms in a bay → crescent shaped ■ Shape is distorted by LSD → causes it to be narrower updrift than downdrift Formation of beaches: ●...
UK’s Uplands: Mountains of Scotland ○ North West Highlands ○ Grampian Mountains by Glen More ○ Central Lowlands (80km wide rift valley south of Grampians) ○ Southern Uplands ● Mountains of Northern Ireland ○ Antrim Plateau ○ Giant’s Causeway (hexagonal blocks of...
Waves: Key words: ● Crest = the top of a wave ● Trough = the base of a wave ● Wave height = the vertical distance from trough to crest ● Wavelength = the horizontal length between 2 successive crests ● Wave frequency = the number of waves per minute ● Fetch = the...
Erosion = the mechanical wearing away of rock with movement ● Remember: CASH ○ Corrasion ○ Attrition ○ Solution ○ Hydraulic action Corrasion (abrasion): ● Destructive waves have enough energy to hurl sand and rocks at the cliff ● Results in scratching/scraping of rock...
Weathering Processes: Weathering = the breaking down of rocks caused by weather conditions , in situ ○ Caused by day to day changes in atmosphere ■ eg/ extremes of temperature or precipitation Chemical weathering: ● Chemical weathering = caused by chemical reactions...
Barton-on Sea = rotational slumping cliff ● Bournemouth = sandy beach ● Sandbanks = spit ● Studland = bay, sand dunes ● Old Harry = stacks ● Durlston Head = headland/cliff ● Seacombe = cliffs ● Kimmeridge = wave cut platforms ● Lulworth = cave ● Durdle Door = arch How...
→ CASE STUDY: Old Harry Rocks, Dorset Caves: ● Several metres high at entrance ● Widest part is at entrance ● Taper a long way back ● Blow hole may form in the roof of cave towards the back → pressure from waves will push water up the hole Sea arches: ● Unsupported...
→ Mass movement = the downslope movement of rock/soil/mud due to gravity → usually triggered by heavy rain ● Scale of movement is determined by extent of weathering on the slope ○ Permeable = water can infiltrate ○ Impermeable = water cannot infiltrate Sliding: ●...