SATELLITE IMAGE PROCESSING AND HEADS-UP DIGITIZATION METHOD FOR THE ASSESSMENT OF WATERBODY ENCROACHMENT USING GEOSPATIAL TECHNOLOGY

Water bodies like lakes or tanks or ponds play a significant role in preserving and restoring the ecological stability. They are in existence for several centuries, serving the water needs of communities. Encroachment of water bodies for development human settlements and farming has been increased due to population growth and public attitude. This research focused on the water bodies encroachment in Manapparai Taluk, which covers an area of 1090 sq.km that encompasses 108 revenue villages and located in the central part of Tamil Nadu, India. The remote sensing techniques were used to assess the land-use land cover (LULC) changes, The visual interpretation techniques were used to prepare the LULC map and investigated the changes between topographic sheets of 1976 and Quick Bird satellite imagery of 2019. The vector layers of LULC were created by using heads-up digitization method in open-source geospatial software environment i.e. QGIS and GRASS. The LULC changes were assessed according to revenue villages, also predicted the total number of water bodies encroached by the public. The results of LULC layers between 1976 and 2019 confirm that the extent of human settlement increased from 3.52% to 5.98% of the total area, while vegetation cover also increases from 1.38% to 2.12%. Besides, the lakes and ponds decreased from 4.11% (44.94 sq.km) to 3.82 % (39.14 sq.km). The research has demonstrated the advantages of QuickBird satellite imagery to provide an exact, cost-effective contribution to prepare a map and investigate LULC changes over an interval.