The impact of land clearance and reclamation for residential and urban infra structural development on the environment

With the high rate of urbanization and industrialization, land clearance and reclamation are general practices to satisfy the demands for lands for development. Land clearance involves the conversion of agriculture lands and naturals areas into a form that is suitable for urban and industrial development. Reclamation involves the establishment of lands on the sea in coastal areas.

In HK, over 10% of the lands for development have been reclaimed from the sea. To support a pollution of about seven million, reclamation has been done extensively to meet the demands for housing, commerce, industry, transports and other facilities.

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’s habitats and hence threatening biodiversity. They are responsible for degrading environmental quality, leading to soil erosion and pollution.

The impact of land clearance on the environment

Forests may be cleared for urban and industrial development. The effects of deforestation on the environment have been discussed before. New urban and industrial areas 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 rainfalls. This may pollute the aquatic environment and also threaten aquatic lives.

The impact of land reclamation on the environment

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 on beaches or dunes, building seawalls and extending the shoreline into the sea, etc. These cause great impact on the marine environments.

Reclamation often involves the dredging of soft mud at the site for loading of a loading of a large quantity of materials 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, from the continuous pounding of ocean waves. They also provide intricate and complex habitats for variety of fish, molluscs, echinoderms and crustaceans. Land filling 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.