5.Discuss on
the
impact of land clearance and reclamation for residential and urban
infra-structural development on the environment.
The Effects
of Urbanization and Industrialization on the Environment
Humans have increasingly altered the
natural environment foe various purposes such as settlement, agriculture and
industry. They have also increasingly replaced the natural landscape with the
urban and industrial establishments.
Urbanization and industrialization are
proceeding all over the world at an unprecedented rate. Because of social and
economic development, there have been rapid changes of land use from
agricultural purposes to urban and industrial purposes. Today, many new urban
and industrial areas are also established on lands reclaimed from the sea.
Urbanization
and industrialization bring about intensive economic growth and technological
development. However, they are responsible for creating serious environmental
problems. For instance, water pollution arises from industrial and domestic sewage, and air pollution arises from industrial processes
and the burning of fossil fuels to generate electricity.
With the high rate of urbanization and
industrialization, land clearance and reclamation are the general practices to
satisfy the demands for development. Land clearance involves the conversion of
agricultural lands and natural areas (such as forests, wetlands and other
habitats) into a form that is suitable for urban and industrial development.
Reclamation involves the establishment of lands on the sea in coastal areas.
In
Land clearance and reclamation have
contributed to the social and economic development in various parts of the
world. However, these human activities have been causing undesirable effects on
the natural environment. They are responsible for destroying natural habitats
and hence threatening biodiversity. They are also responsible for degrading
environmental quality, leading to soil erosion and pollution.
Forests may be
cleared for urban and industrial development. New urban and industrial areas
are also converted from agricultural lands. This may have dramatic effects on
the soil condition. Soil may be washed away from the bare ground during heavy
rainfall. This may pollute the aquatic environment and also threaten aquatic
loves.
Land reclamation for urban and
industrial development usually involves topographical and hydrological
modifications. The operations include draining and filling of marshes and
wetlands, constructing residential houses or resorts in the beaches or dunes,
building seawalls and extending the shoreline into the sea, etc. These cause
great impact on marine environments.
Reclamation often involves the
dredging of soft mud at the site and loading of a large quantity of material
into the site for land formation, all these practices have direct impact on
marine organisms, especially coral reefs. Coral reefs provide a highly
protective barrier for coastlines, such as beaches,
form the continuous pounding of ocean waves. They also provide an intricate and
complex habitat for a variety of fish, mollusks, echinoderms and crustaceans. Landfilling can also directly kill these marine organisms.
Physical removal of seabed can cause
immediate injuries to the natural marine communities. Clouds of suspended
sediment adversely affect marine life through the decrease in light penetration
into water for photosynthesis of seaweed and phytoplankton. In addition,
certain constituents of the sediment may react with substances in the sea and
lead to an increase in water temperature. As a result, water holds less oxygen
and this can be detrimental to marine lives.
Urbanization and industrialization
exert pressures on the environment. The undesirable effects are listed as
follows:
1. The loss of trees, shrubs, and other natural
vegetation results in the destruction of habitats for wildlife. These also results
in soil erosion and extinction of some native species.
2. The conversion of farmlands into urban areas results
in the reduction of food production.
3. The rapid migration of people from rural areas to
urban areas results in an increasing consumption of resources, such as fresh
water and fossil fuels.
4. Roads and buildings so not absorb rain water as
vegetation does, leading to flooding and landslide problems.
5. The production of pollutants from industries, vehicles
and burning of fossil fuels in power stations cause serious air pollution,
leading to acid rain and global warming.
6. Domestic and industrial sewage seriously pollute the
aquatic bodies, and may also cause health problems to human and aquatic life.
7. The incineration of solid wastes further contributes
to environmental problems, such as global warming and air pollution.