Sustainable cities: How far away are we from?
CITIES are considered the cradle of civilisation. Cities have been the centres of education, rule and business throughout the human history. People of cities are usually more conscious and progressive due to exposure to refined knowledge and closeness to rulers. They are 'elite' compared to the rural people. Moreover, employment opportunities and comfort of living attract people from the rural areas where they are found to be pressed by various problems like river erosion and unemployment. How cities are founded: Cities were founded by people where communication systems were easy to develop, near coast or beside a river, for surface or air communication was not developed then. Now planned cities are incepted in a place where there is plenty of land suitable for construction of houses and other infrastructures. But in both the cases a site was or is selected for human settlement considering some factors such as fertility of hinter-land, natural communication facilities, safety from various hazards like flooding, cyclone. However, advancement in science and technology has made it possible to build a town or city anywhere on the earth, only requirement is sufficient land. Key-conditions: In a city the population density is usually higher than in the surrounding areas. Urban area is demarcated by land use pattern. According to the Urban Development Directorate (UDD) of Bangladesh, the land area of a locality can be called urban if more than 80% of it is used in non-agricultural purposes. Industrial zones are situated within the periphery of big cities. Offices of business and governments are located in cities. Since population density is very high in urban areas people suffer from density related hazards in a city. Slums with poor sanitation condition and scarce supply of pure drinking water, unhygienic disposal of solid waste, discharge of industrial waste in water bodies are some of the problems. People living in a city are more exposed to unwanted sounds and public health is also more intensely hampered by air pollution. Urbanization and the case of Dhaka: With the passage of time more people are going to live in the urban complexes world wide. By 2030, towns and cities will be home to almost five billion people. The urban population of Africa and Asia will double in less than a generation. Dhaka's metropolitan area now has a population of some 12 million. Dhaka is projected to be the world's fourth most populous city by 2020 with 22 million inhabitants. With the expansion of the urbanized area the greening process has to be considered, while the green spaces in the old, intermediate and new towns are under great pressure. Salient features
High population density: Urban complexes are manifested by highly dense population living in a small land area. Because of this crowding, the exposure of people to hazards is extreme. The intensity of destruction caused by an earthquake surpasses the destruction to rural area. The incidence of water borne diseases in an event of flooding is several times more than in rural areas. Rapidly changing landscape: The urban areas in the developing countries are engulfing natural land at the maximum rate in the world. The expansion of cities is causing destruction to forestland, filling of wetlands and loss of agricultural land. The situation in the developing countries like Bangladesh is some sort of extreme in this regard. Cities in Bangladesh are growing at a tremendous speed. Huge waste generation: The urban areas produce huge amount of waste on a daily basis that may become un equally huge problem for the city if not managed properly. The waste comes from industrial, household and official sources and ranges from innocuous organic to synthetic polymeric to radioactive waste. Another source of waste in a growing city is the construction sites that generate excavated earth, dust and debris in huge quantities. Production and consumption of industrial goods: The conspicuous feature in the lifestyle of urban people is the extensive use of industry produced goods. This, however, generates employment and income to the benefit of economy. Shrinking green space and dwindling biodiversity: The greenery decreases with the progress of urbanization. People forget or tend to ignore the importance of open space and trees. Many people who think about the importance of green spaces and want to have homestead garden also cannot manage enough money to buy so much land. The government offices and government quarters only have such provisions and must keep it up build new houses and offices sparing considerable open and green space. Socioeconomic life: Importance of any thing in a city is considered according to the economic utility or monetary value it can provide to people. Life in urban area is not generally blissful. The landless people who are forced to come to the city for earning livelihood always face extreme conditions. Even the middle class people are compelled to work a lot if they want to maintain at least a modest standard of life in city. Over all the urban area is a place of competition where candidates are increasing but resources are scarce. As a result people except those of the high society are always busy to earn their livelihood or striving for survival. They have no time to think about its environmental condition. Vertical growth: The land area is limited on this planet. So, urban growth also encroaches upon land previously used as agricultural field or for other purposes. Mainly for scarcity of land and also many other reasons horizontal expansion of a city is restrained. The city planners must think about the vertical growth, constructing multistoried building . Urban environment
Characteristics: Urban environment is the combination of built environment and natural environment. An urban area can encounter the following geographical features: Rivers, mountains, forest, desert, plain land and coast. Importance of natural features:
Wetland: to be used as lagoon to treat liquid waste, ground water recharge Forest and vegetation: for capturing air pollutants and water-shed management, ground water recharge Open spaces: as ground for material recycling of organic waste, ground water recharge Mountain and hills: as source of water , conservation of mountain ecosystem, ground water recharge River: source of municipal and industrial water and sink for waste water Urban infrastructure:
Structures: airport, seaport, bus terminal and railway stations Transportation: roads and highways, bridges and culverts, Utilities: water, gas and electricity supply , telephone, sewerage system and waste management Pressure on environment: Population growth and horizontal expansion both create pressure on environment with pollution effect and farmland enchroachment. Zones of a sustainable city: Ideally there are -- residential area, government and commercial complexes, industrial area, hospital, parks, educational and research institutions, markets, sporting areas and some maintained wilderness Origin of crisis: rapid growth of areas, high density of population, unplanned infrastructure development, rapid and indiscriminate industrialisation are supposed to be the main reasons of urban crises. Challenges: waste management, waste water treatment process, air pollution control, biodiversity loss recovery etc are some challenges the city dwellers face. Major problem areas: Trouble shooting must be constant in the following areas for sustainability. -Transport: intra-city and inter-city -Utility services -Sewerage system -Public facilities: Parks ,lakes, markets and hospitals -Waste management Environmental banes: These cannot be turned into boon but should be contained at a sustainable level. -Ground water depletion and pollution -Pollution of surface water -Solid waste -Sound pollution -Air pollution -Radiation hazard -Pressure on green and open spaces -Green house gas emission -Deterioration of sanitation and hygiene Some options for a sustainable city can be: -Compact settlement -Mixed land use -Production of renewable energy within the urban area -Maintaining water quality, food safety and public health -Solid waste management -Air quality management -Controlling noise pollution Conclusion
We need sustainable cities worldwide to achieve the sustainability of the planet itself. Because it is the cities which are responsible for the human induced global warming and climate change. In the coming years more people will be living in the cities world wide. It is the right time to develop sufficient infrastructures including transport, utility services and housing for people migrating to urban areas while ensuring their sustainability-- environmentally. And in such efforts developing countries need both fund and technological assistance from their developed counterparts.
For all latest news, follow The Daily Star's Google News channel.
Comments