Urban Problems

1
Urban Problems
2
Urban Climate

• The amount of radiation received on urban ground
  surface is (greater / less) than in rural area.

Albedo is greater because of greater reflection
from metallic screen wall and concrete
surface Greater scattering for more cloud cover
and dust particles
3
Urban Climate

• The annual mean temperature in urban area is
  (higher / lower) than rural area.

Artificial heat sources e.g. air
conditioner Concrete surface can be heated up
nore quickly Less heat loss through latent heat
in evapotranspiration Greenhouse effect from the
concentration of CO2 and dust particles
4
Urban Climate

• The relative humidity in urban area is (higher /
  lower) than rural area.

The higher temperature lower the relative
humidity Concrete surface and artificial drainage
system drain out most water. Less amount of is
moisture available.
5
Urban Climate

• The occurrence of fog is (more / less) frequent
  in urban area.

More dust particles as condensation
nuclei Temperature inversion due to
pollution Lower wind speed
6
Urban Climate

• Amount of precipitation received in urban area is
  (more / less).

More dust particles as condensation
nuclei Temperature inversion due to pollution The
high temperature in urban will form a low
pressure centre which brings convection current.
7
Urban Climate

• The mean wind speed is (higher / lower) in urban
  area.

The tall buildings form barriers. Buildings and
streets create rugged relief which will lead to
turbulence
8
Urban Climate

• The visibility in urban area is (higher / lower)
  than rural area.

The presence of fog. Concentration of dust
particles
9
Urban Heat Island
A
B
10
Impact cause by an urban heat island and urban
climate

• the greenhouse effect and artificial heating
  will lead to the formation of an urban heat
  island which means that the urban area,
  especially the C.B.D. and industrial centres,
  will have higher temperature than the surrounding
  rural areas.
• The heat island at the same time makes the
  urban area a low pressure centre where all winds
  are blowing to the city centre.

11

• The relatively high air pressure in rural area
  forces air to move back into the city.
• These will lead to a closed circulation in
  the city which means pollutants cannot be
  diffused.
• Concentration of pollutants will lead to smog,
  acid rain
• Lower wind speed will prevent the diffusion of
  pollution.
• Lower relative humidity and pollutants affect
  human health, especially respiration system

12
Conflicting interest of different parties
.'Pedestrianise" the heart of shopping
area .Introduction of LPG taxi and no-rail tram
.Using unleaded oil and fuel with low sulphur
content .Fine on excess heat emission
13
Support More strict control is needed Wider scope
should be covered The government and large
companies should do more.
Green Group
14
We have to face keen competition Those measures
will increase the cost of production. The
government should provide assistance such as
lower tax and financial support
Businessman
15

• more widespread green area
• separate land use zones
• heat emission plants on downwind location
• control spacing between buildings and height

Do they work?
16
Hydrograph
Discharge
Peak flow
Lag time
Time
17
Impact of urbanization on hydrograph
Before Urbanization After Urbanization
Peak Flow
Lag Time
18
Changes brought by urbanization

• Deforestation, vegetation replaced by concrete
  surface
• Which is smooth and impermeable
• There is less retention and infiltration
• With the aid of artificial drainage system
• Surface runoff reaches river channel much faster

19
Problems brought by urbanization

• High peak flow means high regime of the river
• There is greater danger of flood after rain storm
• However, the discharge becomes small at other
  time
• It will lead to accumulation of sediment and
  pollutants along the river courses

20
Efficient Transport System

• Sufficient and stable supply of transportation
  facilities for workers and other commuters, as
  well as for freight
• Commuters, industrial goods producers and buyers
  are able to make use of facilities without
  unnecessary difficulties, at a reasonable cost,
  and with a high degree of safety and reliability

21
Efficient Transport System

• A land use layout of the whole city and within
  each section of the city that
• Minimizes the distance of traffic flow between
  activity centres
• Discourages unnecessary traffic flows without
  affecting industrial output
• A well maintained transportation system that
  ensures the above-mentioned conditions

22
Major causes

• Improper and insufficient land use and transport
  planning
• Mismanagement of transport facilities
• Improper and insufficient land use control
• Sudden surge of traffic demand due to
  in-migration
• Lack of an inductive business environment to
  promote transport improvement
• Poverty and lack of fiscal ability for transport
  improvement

23
Suggested Solution

• build more roads to accommodate the growing
  number of cars
• increase the flow capacity of existing roads by
  better management (e.g. 'tidal flow' scheme that
  was once used by Lion Rock Tunnel, or build
  flyovers that separate pedestrians and cars)
• improve public transport or give priority to
  public transport(bus lane) so that fewer people
  feel the need to drive

24
Suggested Solution

• restrict the inefficient road users (e.g.
  Singapore's policy to charge private cars with
  less than 4 people inside when they entre the
  C.B. D. during the rush hour)
• control the number of private cars by imposing
  high tax on owning a car
• reduce the number of parking space so as to
  discourage people from driving into some area
  (e.g. the beaches of Hong Kong Island in summer)

25
Suggested Solution

• encourage major employers to modify their working
  hours
• land use control in newly developed area, so that
  people need not travel long distance to work or
  to school.

26
Ranking
A B C D E
1
2
3
4
5
27
Your group's choice? Why?
28
Hong Kong Case

• Hong Kong Moving Ahead A transport strategy for
  the future
• http//www.info.gov.hk/tb/highlight/index.htm
• Railway Development Strategy 2000
• http//www.info.gov.hk/tb/highlight/index.htm

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How transport problems affect the growth of a
city

• increase in congestion leads to an increase in
  transport cost and a decrease in economic
  productivity
• congestion leads to a distorted land use pattern
  in the long run, causing more serious transport
  problems in the future
• transport problems discourage decentralization
  and re-distribution of economic activities and
  population.

30

• increase in traffic demand caused by the influx
  of 'migrants' hinders the smooth implementation
  of urban transport development plans
• insufficient 'space' available within the built
  up areas to allow large scale urban transport
  improvement programmes, thus hindering future
  growth
• the lack of proper inter-modal coordination leads
  to increase in transport cost as well as
  reduction in overall urban productivity

31
Criteria for the assessment of housing quality

• Scenic beauty / view
• Relative position
• Accessibility
• Access to shopping facilities
• Social and public facilities
• Neighbourhood environment
• Open space and green area
• Free from pollution

32
Criteria for the assessment of housing quality

• Internal structure
• Ventilation, brightness, spacious
• Basic services such as electricity, water,
  sewerage
• Social environment / socio-economic status
• School net
• Reasonable / affordable cost

33
Common housing problems

• Housing shortage
• Overcrowding conditions
• Poor sanitation
• Environmental pollution
• Fire hazard
• Unaffordable rent / value
• Social problems (family conflicts, mental
  distresses, theft, crime, etc.)

34
Common housing problem features

• Urban slums
• Urban ghetto
• squatters

35
Causes of housing problems

• Rapid population growth because of large natural
  increase
• High birth rate and relatively low death rate
  resulted from improved sanitation, upgrading
  medical facilities, control of diseases, better
  nutrition and absence of war
• Large rural-urban migration

36
Causes of housing problems

• Slums are found in transition zones next to CBD
  where houses are deteriorating and without
  adequate amenities and the tenants are too poor
  to improve the living conditions
• Over-crowdedness results when a tenant rent part
  of a dwelling from the owner and then sub-let
  parts of this rented accommodation to others

37

• Environmental pollution results because workshops
  and retail units intermingle with residential
  units
• Housing is scare because of poor financial
  support from government and feeble capital
  investment from private developers
• Even when public housing schemes are provided,
  they are frequently inappropriate to the urban
  poor in that most of them are located at urban
  fringe which means high costs to work and fewer
  employment opportunities

38

• Squatters are found on roof tops, hillslopes
  fringing the urban areas and on silts ot boats in
  sheltered coastal areas near the city
• They are usually the result of large influx of
  new-comers to the city
• These squatter huts are built of wood and
  cardboard, there is no surfaced road, no
  electricity, no water nor sewage facilities
  creating fire and health risks
• Poor financial situation and administration of
  local government

39

• Kinship and clanship persist here and there
  resulting in ethnic and social segregation
• Lack of town planning in the early stage of
  development
• Urban decay
• Social segregation

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Solutions
Developed Countries Developing Countries
Slum clearance Squatter clearance
Renewal/redevelopment Self-help schemes
Provision of better public utilities Renewal/redevelopment
Encourage private investment Birth control and family planning
New town development New town development
Rehabilitation More balanced economic development
41
Need for Urban renewal

• At present, there are about 9 300 private
  buildings in the Metro Area (i.e. Hong Kong
  Island, Kowloon, Tsuen Wan and Kwai Tsing) which
  are 30 years' old and above. In ten years' time,
  the number of buildings over 30 years' old will
  increase by 50. The problem of ageing buildings
  is most serious in older urban areas

42
Urban renewal can help alleviate urban problems
by

• thinner the population density of the inner urban
  decentralization of population can solve the
  over-crowding problem
• improve the living environment more open space,
  green area, and community facilities are provided
  
• get rid of the worn-out buildings which impose
  danger of collapse to the residents

43

• refresh the poor looking of the old developed
  areas so to improve the impression of the city as
  a whole
• increase accessibility and improve traffic
  problems by road-widening, redesign of street
  pattern and more parking space
• provide more land for developers, then more
  economic activities can be found
• Land use planning land use zoning policy can be
  adopted in the process of renewal. Offensive land
  use can be relocated or isolated. Different land
  uses will be separated.

44

• redistribution of population low income class
  may be resettled and better new buildings and
  better living environment will attract higher
  social classes to live in the area. The
  socio-economic status of the area becomes higher
  and a balanced community can be attained.

45
Interests and needs of different social groups

• The landlords demand for higher compensation and
  acquire land ownership after redevelopment.
• The old residents of the area want to preserve
  the social bonds and neighborhood relationships.
  The small business owners do have fear of loss
  small business. They want to have resettlement in
  the same district. They are reluctant to leave.

46

• The lower income class has fear of loss of
  existing employment opportunities. They are
  unwilling to pay for higher rents after
  redevelopment and they are unable to afford the
  higher living expenses after redevelopment.
  Higher compensation is demanded.
• Land developers want to raise the economic
  potential of the area. Therefore, improvement of
  accessibility, land and facilities for economic
  activities are important. They also emphasis on
  the balance on cost and benefit on redevelopment.

47

• Town planners emphasis on a balanced community
  and land use zoning. The lowering of population
  density is also important. Adequate open space
  and green area should be kept.
• Environmentalists emphasis on the maintenance of
  urban ecological balance. The preservation of
  historical landmarks and buildings is important.
  The social life and tradition of the community
  should also be considered.

48

• The government officers concern the time and cost
  of land acquisition. The problems involved in the
  process of redevelopment such as traffic
  congestion and pollution should be settled.