The impact of urbanization and industrialization

1
The impact of urbanization and industrialization

• on the quality of the environment

2
Impact on Ecosystem

• In the urban area, wild life is rare, but there
  is an increase in domestic pests.
• Urbanization subtracts and adds various types of
  plants.
• The original vegetative cover is differentially
  destroyed to make way for construction.
• Men can bring new plants into the city and plant
  them.
• The increased planting of different and exotic
  types of trees along the streets increases the
  variety of vegetative cover.

3

• Urban plants are subjected to a number of
  environmental stresses which are absent or less
  severe in the countryside, the trees must
  withstand the reduced supply of water and oxygen
  in the paved-over soil.
• The normal cycle of nutrients is interrupted
  because men remove the grass and fallen leaves on
  the ground rather than allow the incorporation
  into the soil.
• Air pollution will also influence plant lives.
  Many trees in the city are out in the open space
  and so they are more susceptible to damage and
  ice than in the forest.

4
Impact on soil

• The reworking of the ground through urbanization
  changes the distribution and the quality of the
  soil
• agricultural land cover by metropolitan
  structures or roads that top soil had been
  scrapped off and buried by built-up area and will
  destroy the agricultural utility of the converted
  land
• mineral materials excavated from earth to supply
  urban construction demands

5

• e.g. sand and gravel to manufacture cement and
  concrete
• this increases marine pollution
• with urbanization and industrialization, mans
  use of land increase the rate of erosion
• erosion by overland flow is the result of
  urbanization such as compacting the ground
  increases the amount velocity of surface runoff
  and consequently
• this hinders the soil replenishment after rain,
  soil nutrients are removed and less for the
  plants

6

• Eroded soil ---lead to sedimentation of lakes,
  rivers, and reservoirs causing economic loss,
  e.g.harbours and waterways have to be dredged in
  order to stay navigable, flooding
• urban and industrial activities alter quality of
  soil, soil can be contaminated by refuse dump,
  subsurface sewage disposal system
• concentrated traffic contaminated the soil of
  vegetation with zinc, lead, etc., mental
  concentrations increase with proximity to roads,
  traffic volume and with nearness to the surface
• with pumping of underground of industrial and
  domestic use, soil moisture and air are absent

7
Impact on rural area

• For land use
• urbanization and suburbanization,urban encroach
  to rural area and city fringe
• anticipation of the city to rural area, land
  price is therefore become more high, only
  government or commercial land users can afford
  the high land price --- more commercial use of
  land in rural area

8

• In order to keep pace with the urbanized society
  and ensure adequate facilities for urban
  population, government will develop recreational
  use in rural use
• with industrialization, there are not enough
  space for more factories to develop --- expand
  industries to rural area, e.g.set up industrial
  estate
• urbanization, less space and crowded, city
  redevelopment, new town planning in rural area to
  decentralize population, new town such as Tin
  Shui Wai, Sha Tin

9

• For population
• at first, population decreases due to rural-urban
  migration
• rural-urban migration because of more job
  opportunities in cities, more stable higher
  income, more adequate social infrastructure and
  facilities, more comfortable life, more
  entertainment for youngsters
• later, there will be more and more population
  starts to move to rural area because of the new
  development of towns, well-developed transport
  links and social utilities

10

• With further development of industries in rural
  area, there are more job opportunities for
  workers that population move from city to rural

11
Impact on the Atmospheric Environment due
toUrbanization Industrialization
12
Urban Climate

• 1) High temperature
• -day temperature increase 0.6?C
• -night temperature increase 3-4?C
• ? urban heat island
• because
• - more heat generators
• e.g. air conditioners and vehicles
• -changes in the composition of the atmosphere
  
• e.g. increase in carbon dioxide and dust,

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• 2) High precipitation
• -relative humidity is lower
• -high precipitation
• because
• -higher temperature
• -lack of water surface limits
• evapotranspiration
• -contains greater concentration of nuclei
• for condensation

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• 3) Change in atmospheric composition
• - more dust particles and pollutants
• - more sulphur dioxide and carbon dioxide
• because
• - more vehicles due to development
• of transport
• lower photosynthesis as deforestation
• 4) Low wind speed
• -rough surfaces of the city increase
  frictions
• because
• - high buildings act as windbreaks

15
Temperature inversion

• temperature increase with
• altitude decrease
• -layer of dust and
• pollutants absorb
• heat radiated
• and become
• warmer

16
Impact on the Hydrologic Environment
17

• 1. Change in runoff
• - deforestations for urbanization and
  industrialization cause less water infiltrates
  into the ground and the volume of overland flow
  will increase. Thus, the discharge during the
  rainy season will increase and the discharge
  during the dry day will decrease

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• 2. Increase in the magnitude and frequency of
  flood
• - rapid erosion as a result of land clearing
  
• for construction will cause the shallowing
  of
• river beds, thus reduce the river's
  capacity
• to hold water
• - the river channels act as temporary
  storage
• and can reduce the flood peak downstream
• but since they are straightened, the time
• required for a given amount of water to
  run
• off shortens and there will be
  concentrated
• flow within a short period. Flooding will
• be more serious as a result

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• 3)Changes in the temperature of water
• - The heat island effect and the discharge of
  heat into water raise the temperature of the
  water
• - Some species of fish cannot withstand the
  warm water so they may be replaced by less
  desirable types of fish.
• - Warm water contains less dissolved oxygen,
  thus composition of water will be change and
  lead the effects of water pollution problems

20
Impact on the relief and landforms
21

• 1. Landslide from cleaning or building on
  unstable slope
• - man-made disturbances associated with
  urbanization
• - cutting and filling for residential hill
  slope development
• - building along the hill slope including
  extensive cutting
• - removal of hillside vegetation for building
  
• - vibration from machineries, eg. pile
  drivers, motor cars.
• - slope failures resulted

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• 2. Ground subsidence because of urban
  development
• - Subsidence is major environmental response
  to urban activities
• - the presence of heavy structural loads,
  e.g. weight of multi-storeys buildings, flyovers,
  especially those constructed on reclaimed land
  
• - alteration of surface mental of mountains
  and reclamation
• - changes in the ground water regime
• - alteration of the position of the water
  table
• - e.g. by pumping underground water supply,
  by altering the drainage
• - change in the elevation of the ground
  surface

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• 3. Conscious remolding of the land
• - Cutting and filling create suitable ground
  conditions for structural foundations
• - Earth materials are often excavated from high
  places and transported to lowlyling place
• - change the landscape and the distribution of
  the soil

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• 4. rising of land surface
• - Disposal of waste
• - Refuse dump as solid waste and the settlement
  of dust (most from human origin)
• - e.g. In the industrial city of Britain, dust
  deposition may exist 300 tons/km2/ year whereas
  in the open countryside, the amount is reduced to
  70 tons/ km2 /year