Remote Sensing and GIS Application for the study of Chure Degradation of Lal Bakaiya Watershed

Abstract

This report deals with the Remote Sensing and GIS Application for the study of Chure Degradation of Lal Bakaiya Watershed. The degradation could leads to become a cause of hazard of this area. This study is intended to develop a methodology for preparation and analysis of hazard map of Lal-Bakaiya Watershed with GIS as a main tool for the data input and analysis. The location of the study area is Lal Bakaiya Watershed in central southern part of Nepal. The eight causative factors considered for the preparation of hazard map are precipitation, soil, land use, distance to road, stream density, geology, slope and slope aspect. For the preparation of the hazard map three steps: desk study, field investigation, data analysis and interpretation were carried out. In the initial phase of the research, collection of secondary data and review of the literature were done. Different thematic layers are then prepared from collected datas. From the field investigation, all information and maps prepared earlier were verified in the field. Analytical Hierarchy process (AHP) is used for the decision making and hazard map preparation. The data prepared and verified data were then analyzed for hazard mapping. This study also shows how the land cover and land use pattern is changing in four different decades of Lal Bakaiya watershed. Validation of the hazard map is done with the landslide inventory map prepared from the past landslide records. The results and hazard map shows that most of the landslides falls near the agricultural areas and barren land areas of the study area. These indicate that human activities play an important role in the hazard areas. Hence it is recommended to control the causes of degradation of the Lal Bakaiya Watershed.