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Open Spaces for Urban Sustainability
As urbanization leads to rapid decline in open spaces across our cities, a rethink leading to enhancement of urban biodiversity and maintenance of essential ecosystem services is a must to ensure a sustainable future for all.
Urbanization is ever increasing - urban sprawls are eating away much of open spaces and environmental degradation continues to be a major problem in many cities as the open spaces available per capita are decreasing. By 2030 more than 60% of the world’s population is expected to live in urban areas with the figure expected to touch 70% by 2050 (United Nations, 2008). Consequently urban sustainability will be a critical challenge, particularly for developing nations like India.
The principles of sustainable development necessitate that any development of land resources is firmed up after balancing ecological, social and economical functions to ensure a sustainable future. Urban sustainability can only be achieved by building the economic, environmental and social health of the city. Open spaces play a critical role in creating ‘urban sustainability’, meaning the pursuit and maintenance of urban form that synthesizes land development and nature preservation. One of the obvious indicators of urban sustainable development is the quality and quantity of green spaces in the city. Greening of the city, or green urbanism, appears to be an important design concept for the sustainable urban form and there is growing realization that urban green spaces are required for creating sustainable urban forms.
Open spaces in urban systems include parks, gardens and road/street side planting. Open space can be categorized in three levels: at the regional level, at city level and at neighborhood level. It is necessary to maintain appropriate areas of open space, have connectivity among open spaces and make these accessible to public at each level to maintain urban sustainability.
Open Spaces enable numerous ecosystem services leading to social, aesthetic and economic benefits to populace inhabiting urban areas. The ecosystem services include urban biodiversity, natural drains for storm water and flood attenuation. Parks and greenbelts act as sinks for carbon dioxide and counteract the urban heat island effect of large built-up areas. Urban forests in the tropical region are known to absorb 200-300 tons of carbon per hectare per year and as such represent a huge potential for climate change related mitigation benefits. Urban parks, gardens and natural landscapes are conventionally better known for their intangible social benefits however increasingly the tangible benefits are coming to the fore e.g. A recent study estimated the total environmental economic value of Beijing’s urban forest to be around 19339 million Yuan. Out of this fruit, timber and fuel wood accounted for only 15.66 % and rest was composed of new value sources such as carbon dioxide sequestration, oxygen emission, rainfall interception, dust retention, biodiversity conservation etc.
It has long been established that the presence of natural areas in urban settings contributes to the quality of life by providing important social and psychological benefits to human societies. A study carried out in nine cities of Sweden indicated that people across all categories, professions and age considered parks/gardens/urban forests as most effective means for stress-relieving and relaxation. Another study undertaken in Guangzhou, China, indicated that more than 50 % of its residents use urban forests for recreational purpose and for stress-relieving.
This inherent benefit gets manifested in the premium that houses in an attractive, green setting attract over houses in a less favorable location. Studies in Finland, Denmark and United States have shown that urban housing properties with associated green spaces and trees fetch higher prices. It has been recognized that a tree rich urban landscape is an important attraction for new business and investors in European and developed Asian countries.
Developing open spaces
There is much debate on desirability of different levels of urban density and the importance of different qualities in local open space provision. With increasing demand for urban land, there is a need to plan open spaces in an appropriate fashion to maintain urban sustainability. Extensive site knowledge and understanding of the ecology of the region is necessary for planning open spaces. To achieve urban sustainability demand on land resources needs to be balanced with maintenance of minimum aesthetic quality essential for shaping ecological services.
- The two main characters of open space that affect urban sustainability are structure and pattern.
- Structure - are the Vertical characteristics of landscapes including plant species, habitat types, and ecological forms.
- Pattern- are the horizontal characteristics like spatial arrangement, size and connectivity of landscape habitat patches (Open spaces).
A comprehensive sustainability project aims at improving biodiversity by providing ideal structure and pattern after building a comprehensive understanding of the ecology of the region. Landscape ecology is a useful tool in planning open spaces for urban sustainability. It is based on three fundamental structural elements i.e. patches, corridors and the matrix. Landscape ecology focuses on spatial pattern intertwined with processes and changes. A patch is a single homogenous area and corridors are connections between patches, which allow flows of material, energy, water and species across the landscape. The degree of connectivity between small patches is an important factor that determines the stability of the system.
The important aspects of green space in urban form are Quantity (percentage of the urban area filled with green space), Quality (ability of the green space to improve urban biodiversity and provide better ecosystem services), Connectivity (inter-connection between the green spaces) and accessibility (% of population with access to green space). Global standards typically recommend atleast a 33% green cover for urban areas. There are many guidelines that can be followed to plan open spaces in urban areas like the LEED ND (Leadership in Energy and Environment Design Neighborhood Development).
According to established best practices, the green area per capita should be >20 m2 which translates into a minimum of 1.25 ha open space per 1,000 residents. Access to open space should be within 250 m of residential areas and 100 % local/native plants should be used in landscaping as this reduces water usage and maintenance while improving urban biodiversity.
Open spaces across many cities in India are decreasing with growing urbanization. Amongst the rare exceptions are cities established after India’s independence, such as Gandhinagar and Chandigarh, where the urban greenery was pre-integrated in the City Master plans at the initial design phase. The per capita green space in Gandhinagar and Chandigarh at 160 m2 and 55 m2 respectively is far more as compared to even traditional green cities such as Bangalore.
A study conducted by the Indian Institute of Science, Bangalore noted that the Bangalore city lost much of its open spaces and urban wetlands due to urban sprawl resulting in over 35% decline in number of water bodies between 1973 and 1996. The loss of open space has also affected the drainage network, local hydrology and the ground water table of the city.
The Ministry of Urban affairs and development, New Delhi has issued guidelines on Urban Development Plans Formulation and Implementation (UDPFI) for protecting environmentally sensitive areas from unplanned and unapproved development and to ensure adequate open spaces in any urban development projects. The urban development agencies of many metropolitan areas have also developed guidelines in protecting open spaces during urban development. However with ever increasing clamor for land in urban areas, the open spaces across many Indian cities continue to face threats and it will take more than just words and written policies to ensure that we don’t create more challenges for shaping a sustainable tomorrow for our future generations.
The ecological importance of urban open spaces and urban wetlands are seldom recognized and as urbanization progresses the threat to open spaces increases. The short term economic benefits of converting land for development rather than retaining it as open space has sometimes led to shortsighted vision in planning. Though the short-term cost of maintaining open spaces may sometimes seem high, the overall long term economic efficiency demands that the State and other collective decision making bodies need to take appropriate measures to conserve urban green spaces. The need for development of green spaces is not yet fully recognized in urban development in developing countries such as ours. It is only in recent times that civic authorities in some cities like Bangalore and Hyderabad have started charging nominal entrance fee for parks and gardens following the concepts of “financial sustainability” and “fair pricing”. Still a lot more needs to be done to sustain such spaces across majority of Indian cities. There is an urgent need to integrate open space planning in urban development based on international guidelines for parameters such as accessibility and availability per capita. A rethink based on scientific principles of landscape ecology and maintenance of essential ecosystem services is a must to ensure a sustainable future for all.
This article has been jointly coauthored by Dhanapal G, an ecological planner and Dr. Pradeep Chaudhary, an IFS , Chief Conservator of Forests.
WCED (World Commission on Environment and Development), 1987, Our common future, Oxford University Press, Oxford.
United Nations, 2008. World Urbanization Prospects: the 2007 Revision. United Nations, New York