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

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

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.

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

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.

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

Urban Climate The visibility in urban area is (higher /

lower) than rural area.

The presence of fog.

Concentration of dust particles

Urban Heat Island

26℃

24℃22℃

28℃AB

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.

Impact cause by an urban heat island and urban climate

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

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

Green Group

Support

More strict control is needed

Wider scope should be covered

The government and large companies should do more.

Businessman

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

•more widespread green area

•separate land use zones

•heat emission plants on downwind location

•control spacing between buildings and height

Time

Discharge

Hydrograph

Peak flow

Lag time

Impact of urbanization on hydrograph

Before Urbanization

After Urbanization

Peak Flow

Lag Time

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

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

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

Efficient Transport System• A land use layout of the whole city and wit

hin each section of the city that• Minimizes the distance of traffic flow betw

een activity centres• Discourages unnecessary traffic flows with

out affecting industrial output• A well maintained transportation system t

hat ensures the above-mentioned conditions

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

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

Suggested Solution • restrict the inefficient road users (e.g. Sin

gapore'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);

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.

Ranking

A B C D E

1

2

3

4

5

Your group's choice? Why?

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

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.

• 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

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

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

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.)

Common housing problem features

• Urban slums• Urban ghetto• squatters

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

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

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

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

Kinship and clanship persist here and there resulting in ethnic and social segregation

Lack of town planning in the early stage of development

Urban decaySocial segregation

SolutionsDeveloped 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

• 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

Need for Urban renewal

• 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

Urban renewal can help alleviate urban problems by

• 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.

• 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.

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.

• 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.

• 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.

• 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.