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Application of Remote Sensing and GIS tools in delineating Environmentally-Fragile-Areas (EFAs) for sustainable land use planning: A case study of Delhi Region
Dr. Amarjeet Kaur1, Venkatesh Dutta2, Dr. D. K. Chaddha3 Research Scholar, Department of Geography, 1. Head, School of Environment Management, Guru Gobind Singh Indraprastha University, Kashmere Gate, Delhi - 110 006. E-mail:amarjeet@ipu.edu 2. Ph.D. Student, Faculty of Policy & Planning, TERI School of Advanced Studies, India Habitat Centre, Lodi Road, New Delhi - 110 003. E-mail: vdutta@terischool.ac.in 3. Former Chairman, Central Ground Water Board (CGWB), Delhi.
Introduction
Land is one of the prime natural resources. Urban population growth and urban-sprawl induced land use changes coupled with industrial development are resulting in unplanned use as well as misuse of land leading to conversion of useful land into wastelands. The changes of land use/land cover pattern over a time period control the pressure on land (Sengupta & Venkatachalam, 2001). The complexity of urban development is so dynamic that it calls for an immediate perspective planning of cities and towns (Sokhi & Rashid, 1999). For a sustainable use of the land it is essential that proper planning and monitoring be done. Timely and accurate information on the existing land use/land cover pattern and its spatial distribution and changes is a pre-requisite for planning, utilisation and formulation of policies and programmes for making any micro and macro-level developmental plan. Accurate, reliable and comprehensive spatio-temporal information on land use practices in a city is prerequisite for sustainable land management. Remote sensing offers cost-effective solutions to city planners data needs for both macro and micro level analysis of the land use planning leading to urban environment management. The better management and rationale use of land calls for accurate and timely changes in the dimension, nature, and spatial balance between exploitation and regeneration. GIS is best utilised for integration of various data sets to obtain a homogeneous composite land development units which helps in identifying the problem areas and suggest conservation measures (Murthy et al, 2001). In regional/urban development planning identification of types of ecologically critical areas and its orientation for future growth is important for balance land use. This type of planning will be useful to promote environmentally protected zones and other fragile land use forms. Latest information so obtained through remote sensing technology on EFAs would undoubtedly be of great value to various agencies like those concerned with land reclamation, soil conservation, and afforestation as well as for planning, selecting priority areas, allocating funds and executing reclamation methods on sound scientific basis (Kaur et al, 2001). Study area Delhi, the capital city of India, is one of the prime mega cities of the world. Situated on 28o30' North latitude and 77o00' East longitude, it lies at an altitude of between 700 and 1,000 feet (213 and 305 metres) and covers an area of 1,485 square kilometres. Situated on the Yamuna River (a tributary of the Ganges River) Delhi is bordered on the east by the state of Uttar Pradesh and on the north, west, and south by Haryana. The region has a tropical steppe climate. The general prevalence of continental air leads to relatively dry conditions with extremely hot summers. Monthly mean temperatures range from 14.3oC in January (minimum 3oC) to 34.5oC in June (maximum 47oC). The annual mean temperature is 25.3oC. The main seasonal climatic influence is the monsoon, typically from June to October. The mean annual rainfall total is 71.5 mm. Maximum rainfall occurs in July (211 mm). The heavy rains of the monsoon act as a "scrubber". North-westerly winds usually prevail; however, in June and July south-easterly predominate. Land use classification The remote sensing technology along with GIS is an ideal tool to identify, locate and map various types of lands associated with different landform units (Dhinwa, 1992; Palaniyandi and Nagarathinam, 1997; Murthy & Venkateswara, 1997; Khan et al., 1999). The timely information about the changing pattern of land use plays significant role in land use planning and sustainable land development. The mapping and monitoring of the land use/land cover requires a land use classification system. One of the most widely used data format for information extraction about the land use and land cover is the infrared False Colour Composite (FCC) image. The extraction of information from such images about ground reality is done by image interpretation for which generally three methods namely photo interpretation, spectral analysis and data integration are used. Prasad and Sinha (2002) describe the image characteristics and visual interpretation techniques of various land cover and land use categories which is summarised in the table 1.
Methodology ![]() Figure 1: Flowchart of simplified methodology Collection of data and preparation of maps The first step in a GIS project is to create a database of spatial, non-spatial and attribute information. In this study data acquired by Indian Remote Sensing satellite IRS-1C, LISS-III has been used as a primary data source for carrying out rapid reconnaissance survey. The false colour composites (FCCs) in the form of geocoded data on 1:50,000 scales have been used to generate land use/land cover map of the region. The interpretation was substantiated by IRS-1C, PAN image through carrying out field surveys for ground trusting. Apart from these data census data and Delhi Statistical Handbook (1998) were also used for a number of auxiliary information. The methodology adopted to generate the land use/land cover map is depicted in figure 1. Data products used for the study
Table 3: Ancillary data used for the study
Preparation of Thematic Maps Thematic maps on land use/land cover were prepared based on the interpreted data using LISS III FCC, PAN, SOI toposheets and the field survey. Visual interpretation and digital analysis of satellite imagery were performed to delineate various land features. Digitisation of Maps and Spatial Data Automation The various thematic maps of 1:5000 scale were scanned and a raster to vector conversion was carried out. Each feature of the point, line and polygon digitised was labelled, as defined in the data dictionary. These labels were used as identifiers to link the attribute data of each feature. The digitised thematic maps then were imported to ARC/INFO as coverages. After executing 'clean' command for topology creation, the dangle node errors were removed interactively in ARCEDIT module. After all offshoot/undershoot errors have been removed, Feature Attribute Table (FAT) was created using 'build' in ARC prompt. Then each land use/land cover category was assigned a code and these codes were attached to appropriate records of FAT interactively. A Look-up-Table (LUT) was also created to assign a shade symbol for each land use/land cover category. Attribute codes for different categories were verified and additional attributes added into the features database. The theme coverage was made ready for updating into map library and also for analysis. Results and Discussions
![]() Figure 2: Distribution of land use categories under EFAs Table 5: The major categories of EFAs identified and their brief description
Sustainable land use planning Maintenance of the productive potential of land resources and checking of land degradation is a fundamental element of sustainable land use. Land refers to not just soil but to the combined resources of terrain, water, soil and vegetation that provide the basis for land use (World Bank, 1995). Land quality is a complex attribute of land which affects its suitability for specific uses in a distinct way (FAO, 1993). Land quality needs to be assessed with respect to specific functions and types of land use. A land with poor quality is like having no land at all. Sustainable land management should enhance the economic performance of land while maintaining the quality and environmental functions of the natural resources, also preserving the cultural aspect of landscapes (LUCC Report No. 3). Data to establish a topology and characterisation of land use intensity and diversity are needed. Data that can relate the time dimension to each land use and its land cover, linked to a sustainable situation is very important. ![]() Figure 3: The Pressure-State-Response (PSR) framework (Modified form various sources) Land use systems in the traditional sense are complex, self-adaptive units that evolve and change in concert with external biogeochemical forces. Land use systems are, or have become human systems by virtue of the universal impacts of population growth and economic activity (Morain, 1999).Land use patterns are all governed by human resource requirements as much as by natural forces, and therefore require delicate management to achieve sustainable yields. Land issues may be grouped into three clusters. This is a loose grouping, not a classification, and some issues fall into more than one group (World Bank, 1995).
Soil and land being non-elastic resources, all the land based needs of the fast growing population has to come necessarily form limited landmass. There is, therefore, an urgent need to control land degradation and restore the locked up production in degraded lands (Ghatol and Larale, 2000). Sustainable land management necessitates precise information on the extent and spatial distribution of the different kinds of the EFAs to plan suitable reclamation or ameliorative measures consistent with the nature and intensity of the problem as well as operational ease with which reclamation/ameliorative measures can be carried out. Hence it is important to provide information on land use/land cover of a region with a special focus on EFAs, to provide early warning of adverse trends and identification of problem areas. The danger of land degradation is most apparent in areas of marginal or fragile lands, such as the semi-arid climatic zones, or soils with severe fertility constraints. Without having adequate knowledge about EFAs in a region, there is no proper foundation for policy formation and decision making on matters affecting land resources at all scales and levels. The present study was aimed at delineating EFAs so as to formulate plans for their efficient management. The findings will be of immense help in formulation of sound environmental management plan of Delhi. The methodology adopted in this study has served to highlight some challenging and relatively unexplored dimension of area-specific problem in the context of micro-level land use planning. References
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