Remote Sensing Techniques for Land Use Mapping of Arjuna Basin, Tamil Nadu
S. Balaselvakumar Research Scholar, Department of Geography, Bharathidasan University, Tiruchirappalli - 620 024. K. Kumaraswamy Reader, Department of Geography, Bharathidasan University, Tiruchirappalli - 620 024 S. Srileka Project Associate, Department of Futurology, Madurai Kamaraj University, Madurai N. Jawahar Raj Lecturer, Department of Geology National College, Tiruchirappalli - 620 001 Abstract In this paper an attempt has been made to mapping the land use and land cover categories of Arjuna River basin using the Remote Sensing techniques. The study area, which is located in the southern part of Tamil Nadu. The basin covers an area of about 1687 sq.km. The basin has basin subjected to different kinds of environmental degradation by both man and nature. The analysis will help for better land management for sustainable development. The analysis is based on primary, secondary and ground data. The primary remote sensing data are included IRS (LISS I, II). The interpretation key of the NRSA (1985) has been used for this purpose. The advantage of the remote sensing data over the conventional statistical data is due to its more reliability, accuracy, time saving and cost effective. The present land use / land cover pattern indicates as follow, built land, agricultural land, forest, waste lands and water bodies. Introduction The unparalleled increase in population growth has resulted in the increasing demands for food, fodder and shelter resources. This calls for rational utilization of the available land and hence the study of its characteristics is crucial in formulating the management and development plans. The conventional methods for the study of land use involves extensive field study which is time consuming and cumbersome. Land use changes are equipped due to the natural and human activities, it can be observed using current and archived through remotely sensed data (Luong, 1993). The information on land use / land cover patterns, their spatial distribution and changes over a time scale are perquisite for making development plans (Dhinw et al, 1992). Remote sensing, the latest advancement in space technology has the capabilities to overcome the shortcomings of the conventional methods. It makes a major technological breakthrough in the method acquiring information on land resources, agriculture, forestry, ocean resources and other studies. In the present study described the various land use / land cover categories. Study Area The study area, which is a sub-basin of Vaippar, is located in the southern part of Tamil Nadu. It is bounded by Gundar basin on the north and other sub-basins of Vaippar on the south. The Western Ghats and Vaduvarpatti odai basin forms the western and eastern boundaries of the study area. It extends from 9˚20ʹ to 9˚45ʹ North latitude and 77˚25ʹ to 78˚05ʹ East longitude (Fig. 1). It covers an area of 1687 sq.km. The average annual rainfall of the basin ranges from 700 to 950mm. Most part of the study area is a plain region. The hilly areas are found confined along the western and the northern most fringes of the area and hence, the high relief areas. The study area is almost extremely covered by metamorphic rocks, which includes different gneieiss, charnockite, limestone and pink granite. The red sandy loam type of soil is found some of the areas, particularly in the central and northern parts of the basin; other soil of skeletal, red sandy, black, alluvial soil area noted in the basin. Database The following data products have been utilized for the present study
The study has made use of various primary and secondary data. The Indian Remote Sensing Satellite (IRS) and Landsat satellite data were visually interpreted for the study of geomorphology and land use. The interpretation is carried out on 1: 50,000 scale using the image interpretation elements such as tone, texture, shape, pattern, association etc., Adequate field checks were made before ascertaining / finalization of the thematic maps. Results and discussion Analysis of Land use features by Remote Sensing Data The various land use categories were identified and demarcated (Fig 2). Using IRS IB LISS II Geocoded and Landsat TM data based on the image interpretation elements. They are described as below. Built up land The built-up lands are areas of human habitation developed due to non-agricultural uses like building, transport, communication, and utilities in association with water, vegetation and vacant lands. These features can be identified with their dark bluish green tone in the core and bluish tone on the periphery. They have a typical coarse and molted texture. These areas are also associated with the network of canals, roads, and railway lines. Apart from the settlement, transportation lines were also identified with their typical straight, sharp and smooth curves. In the study area, three major settlements are distributed randomly, two of which (Srivilliputhur, Sattur) are found in the southern part and the other in the east (Virundhunager). Few smaller settlements, which represent the minor towns were also mapped and this include Watrap, Peraiyur, Kallupatti, Tiruthangal and others. The total area covered by the major and minor settlements in the basin constitutes 21.07 and 52.75 sq.km. 4.73% respectively. Agricultural land These are the lands primarily used for farming and for production of food, fiber, and other commercial and horticultural crops. By the help of satellite data, it is possible to identify the various agricultural lands upto level III. The information about the kharif, rabi and double cropped areas were identified with the help of multi date satellite data. The various categories of the agricultural lands identified in the study area are described in detail.
Forest, which comprises of thick and dense canopy of tall trees, which predominantly remain green throughout the year. These lands are discerned by their red to dark red tone and varying in sizes. They show irregular shape and smooth texture. These forest areas are found on west, northwest and northern tracts. It is found on the hill slope of Thaniparai, Perumalswami Uchi, Rajamparai, Valangai Mottai, Thaniparai Medu, Muriamppanjam Mottai, Karikkadan Kombu and Kamba Ittu Malai. Based on the tonal and textural variations, the forests of the study area were divided into three categories as dense, open and degraded. In the study area, the various forest classes, their distribution and their characteristics are described in the following sections.
Land, which in its present state does not or only possess limited ability to support vegetation, is called wasteland. Eroded soil, ravine, rock, sand dunes and active depositional features are included in this category. These may result form inherent / imposed constraints such as location, environment, chemical and physical properties of the soil. In the study area, there are three categories of wastelands, which could be easily identifiable from the satellite image.
Both man-made and natural water features covered with water are included in this category. i.e. rivers / streams, lakes, tanks and reservoirs. The water features appear black in tone in the satellite imagery. They shallow water and deep water features appear in light blue to dark blue in colour. In the study area, a number of tanks are evenly placed all over the basin except southeastern portion. The lakes and tanks can be delineated very easily by using land sat imagery. In some of the tanks energy plants, scrubs and bushes cover them. They appear as light red in tone. The area under water body in the basin is covered by 191.61 sq.km (11.36%). A few reservoirs are also found in the northwestern hilly area and in southeastern parts of the study area. Conclusion The land use categories of the study area were mapped with the help of IRS and Landsat data. The land use categories were demarcated viz. built-up lands, agricultural lands, forests, wastelands and water bodies. The built-up lands include towns and villages/ minor towns. The total area covered by this land use category is about 74 sq.km. In area under agricultur, it was possible to identify the croplands, fallow lands and plantations. Using multi date satellite data it was possible to identify the kharif, rabi and double cropped areas. Agricultural areas are to be found well distributed throughout the study area and their aerial extent were calculated and tabulated The forests of the study area are confined to sub basins 1 and 3 covering the hill slopes of Thani parai, Perumal Swami uchi, Rajam parai, Valangai mottai, Thani parai medu, Mariyampanjam mottai, Karikkadan kombu and Kamba ittu malai. The forests occupy about 166 sq.km. Of these, open forests occupy more areas than the dense and degraded forests. Wasteland categories, such as land with / without scrubs and barren rocky areas were demarcated. The land with / without scrubs areas are found near Srivilliputhur, Sivakasi, and Sattur areas, while the barren rocky areas are found in the vicinity of the hilly areas. In the water body category, features such as rivers / streams, tanks and reservoirs were delineated. In the study area, several streams / rivers representing the Periyar, Meenakshipuram, Mannarkottai, Mel uppu odai, Kaushiha Mahanadhi etc. were identified. The tanks were to be found well distributed throughout the study area, except in the southern area where they are less. A few reservoirs were also identified in the northwestern hill and in the southeastern parts of the study area. Reference
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