Ansuman Chakraborty
[email protected]
Abhishek Kumar Jha
[email protected]
Praveen Kumar
[email protected]
Students, Department of Remote Sensing & Geoinformatics,
Birla Institute of Technology, Mesra, Ranchi, India
Introduction
With the advent of the 21st century, not only has development in India gained momentum but there is also an upward social mobility among a population of billion. Economic activities, coupled with infrastructure development to meet the requirements of unprecedented population growth and migration into urban centres, has resulted in extensive urbanisation, almost 3 percent annually. Consequently, urban and peri-urban areas are expanding, with a change in land use along the highways crossing the cities and in the immediate vicinity of the cities.
Patterns of spatial and temporal urban changes can be analysed cost effectively and efficiently using spatial and temporal technologies such as GIS and remote sensing (RS) along with collateral data such as Survey of India (SOI) maps, etc. GIS and RS are land related technologies and are therefore very useful in the formulation and implementation of the land related component of sustainable development strategy. The different stages in the formulation and implementation of a sustainable regional development strategy can be determination of objectives, resource inventory, analyses of the existing situation, modelling and projection, development of planning options, selection of planning options, plan implementation, and plan evaluation, monitoring and feedback (Yeh and Xia, 1996). GIS and remote sensing techniques are developed and operational to implement such a proposed strategy.
The spatial patterns of urban expansion over different time periods can be systematically mapped, monitored and accurately assessed using satellite data (remotely sensed data) along with conventional ground data (Lata et al., 2001). Mapping urban sprawl provides a “picture” of where this type of growth is occurring, helps to identify the environmental and natural resources threatened by such sprawls and suggests the likely future directions and patterns of sprawling growth. Ultimately, the power to manage sprawl resides with local municipal governments that vary considerably in terms of will and ability to address sprawl issues.
Study area Ranchi city lies at the intersection of 23° 22′N latitude and 85°20′E longitude on the north-west bank of Subarnarekha River within the Chhotanagpur plateau in India. This city is situated at an altitude of 2128 ft (618 m) above the mean sea level. The area of Ranchi city as per Ranchi Municipal Corporation (RMC) boundary is 224 sq. kms. This includes 37 municipal wards. As per Census 2001, Ranchi city area has a population of 847,093. According to most recent estimates, the population of the city is nearly 12,00,000 with a floating population of 50,000 to 60,000. The population density is about 400 persons /sq.km.
Fig 1: Showing the Ranchi Urban Area
Data used and methodological framework
In order to study the change of spatial extent of growth and infrastructural facilities, SOI toposheet number 73 E/7 along with IRS PAN with a resolution of 2.5m, LISS-III and LANDSAT-TM was used to generate different layers of years 1972, 2004, 2006 and 2010 respectively. The census of the city was integrated with the above mentioned data to identify the elements at risk associated with different forms of urban hazards. Methodology of the work involved utilisation of RS data of the city area for deriving spatio-temporal information on the urban landuse. This allowed generation of information on important physical environmental parameters of urbanisation including city infrastructural details.
Fig2: Methodological Framework of the study
These were supplemented with collateral information and ground surveys. As ground level information, base map and GCP requirement, Survey of India topographical sheet no. 73 E/7 in conjunction with other collateral information were used. The basic RS techniques followed were the image pre-processing, processing and interpretation and analysis using the software like ERDAS IMAGINE 8.6 version, Arc GIS 9.2 Version, Arcview GIS 3.2 Version and so on. Finally all the data were integrated in the GIS software to generate the different series of maps and charts to understand the different parameters of urbanisation of the city and different other physical and cultural phenomenon. An attempt has also been made to suggest a model plan for the future development of the study-area.
Impact assessment of urbanisation
The study clearly exhibited that the spatial extent of the city had undergone changes in terms of a haphazard and unorganised growth over last few decades, along with the leaps and bounds increase of population, road network, different facilities, often exerting tremendous pressure upon the resources available in the study area as well as speaking over the sustainable development of the area under supervision.
Different sub-categories of the study include:
Urban Expansion: Ranchi started as a small city with an area of around 6 sq km in 1869 and population of approximately 12,000 in 1871. The area gradually increased to 55.44 sq km in 1965, 97.12 sq km in 1972 and stood at 212.29 sq km in 2004 and finally in 2010, it covered 273.23 Sq.Kms. From 1965 to 1972, the city grew with a growth rate of 2.08 Sq.Kms/year; during 1972 – 2004, the city grew at a rate of 6.08Sq.Kms/Year and during 2004 – 2010, it grew at a rate of 10.16 Sq.Kms/Year (RMC and Satellite data interpretation). Simultaneously, spatial growth the population too grew by leaps and bounds. Most of the extension occurred at the cost of scanty fertile and plain agriculture land, since the city is surrounded by hills and plateaus, which may be the harbinger of food scarcity and green space non-availability in the future decades. Moreover, satellite imagery also supported the finding of the study.
Fig3: Physical Expansion of Ranchi city
In 1972, the total urban area has been 97.12 sq. km, which increased in an unorganised and irregular way to 212.94 sq. km in 2004 and further extended to 273.23 sq. km in 2010.Thus, a massive growth was registered with the inception of the idea of the city, turning into the capital territory, luring people to settle here, enjoying the best available infrastructural and institutional amenities. In 1972, the city area has been 34.52 sq.km, which increased to 103.58 sq.km in 2010.
Fig 4: Some Identified Sprawl locations in Ranchi (1972-2004) {left} and (2004-2010) {Right}
Road network expansion: Along with the expansion of the spatial extent the city has also undergone expansion of the road network, be it metalled or un-metalled, but in a very irregular and unorganised fashion. The growth has basically come up at the expense of the agricultural or fallow lands or the wastelands. Although the expansion took place to commemorate with the growing population, but the ever increasing population pressure has thrust in such a fashion that now-a-days congestion of traffic and accidents are a frequent phenomenon. Presently, the total road network of the city is about 683.73 km, while in 1972 it was only 196.43 km.
Table1: Road Transport Network of Ranchi
Over the last 15 years in particular, vehicles in the city have increased more than 3 times. The registration records of the Regional Transport Authority, Ranchi indicate that the registration of vehicles, both public and private, increased by 224% between 1980-81 and 1990-91 due to large industrial growth in this period, however the growth reduced to 63% between 1990-91 to 2000-01, as listed in the table below, further it is expected to grow at not less than 100% till 2021.
Fig6: Road Network Map of Ranchi 1972 and 2010
Loss of water bodies: Over the last forty years, expansion of the urban settlement has left adverse impact on the health of surface water bodies. Apart from the lessening of the numbers (around 300) of water bodies, it has also lead to the shrinkage of wetlands. Now-a-days, residential or business apartments, at the expense of the water bodies, have become a common phenomenon in the city.
Map 8: Surface Water bodies Change Map (1972-2010)
A simple statistics made it clear. In 1972, the total area under the surface water bodies was only 66.23 sq. km, while in 2010, the area was 62.14 sq. km. The area under the major reservoirs of the study area (Kake, Ranchi lake, Hatia reservoir) too has undergone shrinkages, with the former having an area of 18.6 sq.km in 1972, becoming 15.26 Sq.Kms in 2010, Ranchi lake initially with an area of 19.23Sq.kms in 1972, becoming 16.7 Sq.Kms in 2010 and the Hatia reservoir with an area of 40.18 Sq.kms in 1972, becoming 29.28 Sq.Kms in 2010. Through this piece of information, it was evident that the major shrinkage of water bodies has taken place in the southward direction, rather than the northern halves. The map generated from the interpretation of the LANDSAT imagery also generated the similar results.
Change in landuse pattern: The land use-land cover pattern of the city has sustained significant changes over last forty years. It was revealed by using image interpretation techniques, to study the land use-land cover changes, over the given time frame. According to the study, over this period of time, the area suffered from substantial decrease of agricultural lands from 1960s, along with the decrease of open space, playgrounds, water bodies, along with the increase of settlements. To justify the validity of the statement, the percentage of different land use map of 1972 and 2010 are provided below.
Map 10: Landuse/Land cover Map of Ranchi City 1972 and 2010
Socio-Economic Changes
The unorganised urbanisation has adversely crept on the economy of the city. Sample social surveys and statistical computations (RMC and other sources) revealed the following situations:
Inflation and market failures: It has been observed that the unfettered growth has laid an over burden of additional expenses over the city. In addition, new developments in the new sprawl areas are putting pressure on the city’s economic reserves. It is resulting in a situation known in economics as a “market failure” (Bruckner, 2000). Another problem which triggered due to this situation is inflation. As the cost of new infrastructure is shared by all the city’s residents the infrastructure-related tax burden on new homeowners is typically less than the actual infrastructure costs they generate, new home-owners are able to pay higher purchase price for their houses. Now, this high amount of money eventually entered the city market in various forms and finally resulted in inflation. This type of condition is witnessed at several places in the city like Pundag, Booty More and Doranda. The socio-economic survey conducted by (Chakraborty et al., 2011) revealed instances of higher price level than the neighbouring markets dominated by the middle or low income group people. This in turn led to price rise in the entire market in the long run and ultimately enhances social disparity.
Central decay and loss of aesthetic benefits from the presence of open space:
As benefits of open space cannot be evaluated in monetary terms, disappearance of open space does not reflect as a monetary loss and thus remains a neglected issue. It was evident in the case of Ranchi city, leading to too much land converted to urban use and resulting in excessive spatial growth of the city. In addition to the disappearance of open space in the city, the city also could be presented as a classic example of the “central decay” phenomenon. With rising incomes and low commuting costs, demand for housing in the aged central city is going down which is resulting in reduced possibility of upgradation and development of the central city.
Increased expenditure on health hazard prevention: The increased and irregular urban spread has led to the development of unhealthy and hazardous condition for living in several localities, especially along the slums, or the low class residential areas leading to the higher expenditure on epidemic control of dengue, malaria, diarrhea, other water-borne diseases and so on. According to the study, the increased population and increased spatial growth of city has led to an increased municipal expenditure of 25 percent on these issues especially over the last decade, which can otherwise be spent on other city welfare and beautification issues.
Reduced social interaction due to low density sub-urban growth: Many commentators criticise the process of suburbanisation and its attendant “car culture,” as weakening the nation’s social bonds by spreading residences out in low-density patterns that discourage interaction. These critics wish to return to a previous type of urban existence, one characterised by the interactive street life that resulted from high densities and intermixing of residences and commercial establishments. Hayward (1998) presents a clear statement of this position.
Conclusion
Based on reality, one should not speak against the urbanisation. Evidences indicate that urban sprawl in study area followed the oriental pattern (as found in the case of most of the Indian cities) and encompassed several unfriendly socio-eco-environmental condition. Efforts should be made to generate ample employment, infrastructural and institutional amenities, restoration of peaceful political state in adjoining rural, urban and satellite towns, to curb down the expanding migration of people. Moreover, efforts should be drawn to delineate the sprawl boundary of the city up to year 2025, and the planning and developmental actions should be taken up accordingly. Apart from these it is also necessary to draft a taxation policy in which the new inhabitants of the city should be equally accountable to share the burden of extra expenditures for building up the additional facilities like sewerage, roads and so on. Furthermore, efforts should be drawn to preserve and protect the present environment and accepting a sustainable way of development.
