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Contemporary Urban Environments (Urban morphology (Physical factors…
Contemporary Urban Environments
Urbanisation
urbanisation - an increase in the proportion of a population living in towns and cities
urbanisation can lead to the formation of megacities (cities with 10 million or more inhabitants)
World city - a city that acts as a major centre for business, etc. and has global influence
More than half the world's population now live in urban areas
Urbanisation can be caused by push and pull factors
Push factors - reasons to move away from an area
Poor infrastructure
War
Poor education
Poor education
Lack of jobs
Famine
Mechanisation of agriculture
Natural disasters
Overpopulation
Pull factors - reasons to move into a place
Perceived better quality of life (bright lights syndrome)
Employment
better nightlife
Better healthcare
Better education
Better infrastructure
Reasons for urbanisation and population increase
Natural increase
Rural-urban migration
Economic processes associated with urbanisation
Industrialisation
Jobs created
Investment into the city
More businesses attracted to the city
Further migration
Multiplier effect
When investment into industry is made in a city it sparks the need for other services which in turn provides jobs and increases industry further
Social processes associated with urbanisation
Higher living standards
Cities become centres of cultural expression
Ethnic diversity can make people more tolerant but segregation can also occur
Technological processes associated with urbanisation
A number of high tech industries have emerged in urban areas
These are highly paid jobs
Political processes associated with urbanisation
Urban areas often cause great inequalities between rich and poor
New political movements emerge to represent the working class
Cycle of urbanisation
Industrialisation
The process of expanding the country's capacity to produce secondary goods and services
Urbanisation
The movement of people to the cities from rural areas
Suburbanisation
the movement of people out of the inner city and into the suburbs
Deindustrialisation
the closing down of industry
Counter-urbanisation
Movement from urban back to rural areas
Gentrification/urban renewal
Gentrification - when people buy houses in poorer but improving areas and do them up and sell them on for a huge profit
Urban renewal - money spent on roads, houses, etc. This is normally by large organisations such as the government
Urban resurgence
When people move back to the cities after they have been improved
Issues caused by urbanisation
Low income countries
Shortage of housing
Slums
Lack of services
Water
Electricity
Pressure on infrastructure
traffic congestion
polluted water
Waste disposal
Health hazard
Harmful to wildlife
Look at Mexico City case study
Waste disposal
Housing
air pollution
Inequality
High income countries
Urban sprawl leads to decentralisation, which leads to decline in retail in city centres
Shortage of affordable housing
Look at Birmingham case study
air pollution
Lack of green space
Waste disposal
Both
Urban sprawl
More infrastructure needed
Farmland lost
More food miles
Wildlife habitat loss
People commute
Congestion
air pollution
Unemployment/underemployment
Increased traffic
Bad for the environment
Harms human health
Suburbanisation
Victorian times
The inner city was overcrowded and lack of sanitation
Only upper classes could afford to move out
Construction of railways allowed people to live outside the city and commute to work
After the wars new houses needed to be built so they were built on the edges of the city
Demographic
Young/middle aged
Affluent
Mobile
Skilled workers and professionals
The elderly, young and unskilled were left behind
Modern suburbanisation
Ideal family home with a garden
We are a car-centred community; we can commute
new estates are being built on Greenfield sites on the edge of cities and towns
Counter-urbanisation
Demographic
Middle class families
Young professionals
Young families
Affluent people
Pull factors
aspirations of a quiet country life
Land and house prices are cheaper in rural areas
Higher car ownership and increase in public transport have allowed access to rural areas
Rising demand for second homes and early retirement
Push factors
Negative reaction to city life
Pollution
Increasing house prices
Traffic congestion
Crime rates
Effects
Modern housing estates are built
Loss of green land
Old properties are converted and modernised
Resentment is caused because young people cannot afford to buy in desirable places like historic villages
Newcomers may not appreciate the traditional values of village life
Conflict
Main population of villages may be commuting in the daytime causing local services to become obsolete
Decentralisation
Brings economic benefit as new population spends money
Pressure on services and infrastructure in rural settlements
Deindustrialisation
Fordism
Mass producing products on a production line
Not very flexible
Post fordism - since the 1970s more flexible and adaptable production methods have been used
Cottage industries
Before Fordism people made things themselves in their own homes
Deindustrialisation occurred in the UK in the 1980s
Causes of deindustrialisation in the UK
It was cheaper to import materials from places like China
More machines were being used so less people were needed
This caused unemployment
The UK struggled to keep up with new technology
The rise of the tertiary industry has resulted from deindustrialisation
It solves some but not all of the problems caused by deindustrialisation
The growth of the tertiary industry is not great enough to make up for the loss of secondary jobs
High paid tertiary jobs need education
In Sheffield
Very industrial
Stainless steel was invented in Sheffield
Deindustrialisation of Sheffield was portrayed in films such as The Full Monty and Brassed Off
Impacts of deindustrialisation
Postive
Water quality improved due to lack of pollution from factories
Better air quality
Negative
Lots of derelict land
More traffic as people have to travel to work as all industry in the city closed down
120000 people lost their jobs
Decentralisation
Merry Hill
Out of town shopping centre near Birmingham
8000 parking spaces
Wide range of facilities all under one roof
Created jobs
Encouraged some town centres to develop
Loss of green open space
Shops from surrounding town centres moved to Merry Hill, leaving them empty
Shops that remained in the town centres lost customers because people stopped visiting
Dudley lost 70%of trade to Merry Hill
More than half of British adults now shop online
Decentralisation threatens retail in the CBD
Urban regeneration
UDCs
Urban Development Corporations
1979
Property led regenerations
This means they were more about building new things rather than improving social factors
London Docklands
Successes
Jobs provided
New homes
Failures
New jobs are highly skilled and only 15% go to locals
House prices too high
Highly paid newcomers cause friction with locals
Loss of community
Focused on economic benefits, there were few social/environmental benefits
City Challenge Partnerships
1990s
The local residents, council and businesses worked together
Increased emphasis on social development
Councils wasted money bidding and competing with each other
Hulme, Manchester
Aimed to improve old housing
Successes
homes were energy efficient
Falling crime
Jobs created
Asda - jobs were suitable for locals
Satisfaction of residents
Flagship developments
Self contained redevelopment projects in key areas such as waterfronts
Late 1990s
Albert Docks in Liverpool
Liverpool now sees 10 million tourists each year
Successes
economic growth
Fifth most desirable retail and leisure location in the UK
Increases pride in history of the city
Failures
More tourists = more pollution
Does not help the poorer members of the population
No investment put into housing
Bull Ring in Birmingham
Business focused
Aim to attract tourists, business and economic investment
Act as a catalyst for regeneration of the wider area
Sustainable communities
21st century
A new concept to tie together the social, environmental and economic aspects of a successful community
Aims to give everyone access to basic needs
Only urban policy to consider the environment
Greenwich Millennium Village
Successes
Makes everything accessible as all facilities are provided in one area
Sustainable housing
Use 80% less energy
New underground station provides connections to other parts of London
Jobs created
More community and leisure facilities
Failures
Workers commute in the daytime leaving the village empty
Housing very expensive
Crime is a risk due the rich residents
Urban morphology
Urban form - the characteristics that make up built-up areas, including the shape, size, density and organisation of settlements
Urban morphology - the spatial structure and organisation of an urban area
Physical factors affecting urban morphology
Lagoon (Venice)
Mountains (Vancouver/Rio de Janeiro)
Sea
Natural harbour (Sydney)
Lakes (New Orleans)
Rivers (New Orleans)
Reclaimed land (Hong Kong/Kobe)
Glacial deposits (New York)
Lake bed (Mexico City)
Burgess model
Based on land value and accessibility
Inspired by Chicago
It applies to cities in developed countries during the 1960s before deindustrialisation
Easy to interpret
Not accurate for m modern cities
Very simple - most cities are more complex than this
Bid rent theory
The value of land decreases as you get further from the CBD
PLVI
Peak Land Value Intersection
Where accessibility is greatest
Secondary land value peaks are caused by out of town shopping centres
Hoyt's model
This sector model is an extension of the Burgess model
Boston was used to support this model
The sectors formed around transport links
However this is now quite outdated
Mann's model
Combination of the Burgess and Hoyt models
Uses the prevailing wind to show where the poorer areas will be because that's where the smoke from the factories will blow.
Based on Sheffield
Harris and Ullman's multiple nuclei model of urban land use
This model shows that modern cities have a more complex structure than suggested by Burgess and Hoyt
Cities do not grow from one CBD but multiple nuclei
Every nucleus has a different function
This model applies to London
Model of the Latin American city
Poorer people live on the outside of the city - the opposite to in MEDCs
Shows gentrification
Shows out of town shopping centres
The city has a spine connecting the CBD to the outskirts
Model of land use in an Asian city
Shows that most major Asian cities were developed by European colonies on ports
Squatter settlements on the periphery
No CBD
Jakarta follows this model
Shows that cities do have mixed land use zones
Shows the new high class zone as well as the original one - showing changes in the urban morphology
Core regions - richer, more developed areas that drive the economy
Periphery regions - poorer, less developed areas that lack resources and wealth. They are normally rural and unequal flows develop between it and the core
New urban forms
Fortress developments
mixed use developments
cultural and heritage quarters
gentrified areas
edge cities
The concept of a post modern western city
Modernist
1920s - 1970s
Boxy architecture
functional, not aesthetic
Bid-rent theory/Burgess model
Mass production in factories
Cities planned in totality
Divisions of class
Not very diverse
Post Modernist
Cities in the present
Odd combinations of architecture
Harris and Ullman multiple nuclei model
More expression of art
Tertiary employment
Cities planned in fragments with more of a focus on aesthetics
Ethnic diversity
Urban microclimate
Urban heat island - a metropolitan area that is a lot warmer than the rural areas surrounding it
Causes
Surfaces have a lower albedo
Air pollution traps in heat
Water is drained away quickly so less energy is needed for evaporation so more is used to heat the atmosphere
Combustion of fuel in vehicles
Air conditioning and heating in buildings release heat
people generate heat
lack of vegetation
Impacts
Uncomfortable conditions for humans
Increase in heatstroke, asthma, organ damage and death
Hot and still weather conditions produce higher air pollution levels
Excessive heat puts an increased strain on the supply of energy for air conditioning
Increased water consumption = strain on water supply
This can lead to water use restrictions
Danger to aquatic systems
Pavements and roofs heat surface runoff which results in thermal pollution
Mitigation
Cool surfaces
Roofs are being built with materials with a high albedo
Cool pavements are also being trialled
Green roofs
Can reduce rooftop temperatures by 20-40 degrees on a sunny day
Act as insulators
Urban greening
Provides shade
Natural cooling effect
Sky view factor
relative openness between buildings that allows heat and pollutants to escape
Microclimate - the small scale variations in temperature, humidity, wind speed, evaporation and precipitation that occur in a particular environment such as an urban area
Albedo rate - the reflection of solar energy from the earth back into space. It is a measure of the Earth's surface reflectivity
Precipiation
Rainfall can be higher over urban areas
The urban heat island effect causes convection
surface winds drawn in from the surrounding area are forced to rise over the urban canopy, causing the formation of clouds
Pollutants can act as hygroscopic nuclei and assist in raindrop formation
Cities produce high levels of water vapour from industrial sources
Fog
The occurrence of fog increases with industrialisation
The abundance of particles in city air act as condensation nuclei and encourage fog formation
the clean air acts of the 1950s resulted in less fog
Water in the atmosphere
Humidity - the measurement of water vapour in the air
Absolute humidity - the mass of water vapour in a certain amount of air
Relative humidity - the amount of water vapour in the air as a percentage of the maximum that it could hold
Air that has reached 100% relative humidity is said to be saturated
Cold air holds less moisture than warm air
Dew point temperature - the temperature at which air becomes saturated
Urban drainage
Storm hydrograph
Factors that affect flood risk
Soil
Increases flooding
Dry sandy soil
Coarse textured soil
Shallow soil
Saturated soil
Dry baked clay soil
Decreases flooding
Deep thick soil
Fine clay soils
Weather and climate
Increases flooding
Intensive rainfall for a number of days
Short summer storm
Decrease flooding
Long dry summer
Terrain
Increases flooding
Steep slope
Decreases flooding
Gentle slope
Human activity
Increases flooding
Urbanisation
Deforestation
Decreases flooding
Afforestation
Urban flooding
Impermeable surfaces = increased surface runoff = increased flood risk
Drains reduce lag times
Urban areas do affect flood risk but they are not solely responsible for it
Urban water cycle
Source ➡️ treatment ➡️ distribution ➡️ use ➡️ collection ➡️ wastewater treatment➡️ source
SuDs
Sustainable urban drainage systems
Grey infrastructure - conventional piped drainage and water treatment systems (hard engineering)
Attenuation tank
stores excess runoff beneath the ground and releases the water slowly
Permeable paving
Rainwater harvesting
similar to attenuation tanks but involves reusing the water
Soakaway
bricks and rubble underground to help water drain through slowly
Geocellular storage
modern soakaway that uses plastic crates
Green infrastructure - natural land and plant based ecological treatment systems and processes (soft engineering)
Rain garden
planted depression that absorbs runoff
Swale/channel/rill
Ditch by a road to drain away the water
Green roof
Wetlands
Green infrastructure is a more attractive option but it requires lot of space
Water pollution and the Thames Tideway Tunnel
In the past cholera has been a big problem in London
A sewer network was built which lasted until 2014
However by 2014 the sewers could not handle London's growing population
The new 25km Thames Tideway Tunnel will last London for 100 years
What then???
People argue that London should be greening instead of using hard engineering
Waste management
WEEE - Waste Electronic and Electrical Equipment
Fastest growing waste stream in the world
Waste stream - the complete flow of waste from its source through to recovery, recycling or final disposal
MSW - Municipal Solid Waste (urban waste)
Improper dumping of MSW impacts
loss of recyclable resources
Contamination of land and water
air pollution due to release of methane from decomposition
Global waste trade - international trade of waste between countries for its disposal, recycling or further treatment . Mostly from developed countries to developing countries.
Air pollution
Smog - smoke and fog
Photochemical pollution - sunlight reacting chemically with industry and vehicle emissions to form secondary gases
Big problem in LA as air pollution is trapped
1 million deaths are caused by air pollution every year
Air pollution affects land use because poor areas are situated in the north east of cities because the prevailing wind blows the pollution in this direction
Particulates are caused by burning any organic material
Particulate pollution is dangerous because it is too small for our respiratory filter too catch so they enter our bodies and stay there causing asthma, lung cancer and respiratory problems
In areas close to industrial or dense urban areas particulates cover the crops and block the sunlight
Managing air pollution
Clean Air Act in 1950s
Congestion charging in London
Low emission zone in London
Hybrid and zero emission buses
Park and ride
Cycle lanes
Bus and car sharing lanes
Use of waterways
zoning industry and higher chimneys
Sustainable urban development
Ecological footprint - the area of land needed to provide the necessary resources and absorb the wastes generated by a community
Dimensions of sustainability
Natural
Political
Social
Economic
Liveability - characteristics of a city which improve the quality of life
Urban resilience - the capacity of individuals, communities, institutions, businesses and systems within a city to survive, adapt and grow no matter what kinds of chronic stresses and acute shocks they experience
