Impact Assessment of Check Dam in the Pappiredipatti Watershed (South India) Using LULC and NDVI Signatures

Abstract

AbstractAgriculture is an essential sector because of the changing phenomenon of weather conditions, which is further complicated by the interaction of vegetation with the environment. The scarcity of rainfall causes physiognomic changes that can be identified by satellite images with reference to vegetation signature and land use and land cover changes. The rate of plant growth as well as to the amount of growth is indicated by vegetation indices. They are sensitive to the vegetation changes affected by moisture stress. Hence systematically, scarcity can be monitored using techniques than ground-based methods of information collection. The capabilities of geospatial techniques have been used to demarcate effective sites for monitoring the functional characteristics of water conservation structures in the Pappiredipatti watershed. In this study, land use/land cover has been used to delineate the existing sites to water harvesting measures. An increase in groundwater resources of runoff storage structures is proposed in the watershed by constructing check dams, percolation tanks and gabion structures. Water conservation sites are erected by considering spatial distribution of land use/land cover and normalized difference vegetation index (NDVI) information of the watershed. Geospatial techniques have been used to integrate spatial information pertaining to functional characteristics of land cover within buffering distances in the proposed site of watersheds. For detailed changes around the recharge area assessment, an attempt was made over the watershed. Crop growth area was assessed in and around forest, barren land and dense vegetation areas using the temporal normalized difference vegetation index (NDVI) in 1985, 2005 and 2015. They were compared with vegetation area regions, and crop-wise area growing was identified. Based on the results obtained from the study area on vegetation cover, the buffers around the recharge area impact were assessed by the NDVI. A decrease in barren land in 2005 was identified by identifying the NDVI threshold over predominantly sparse vegetation growing regions, and crop-wise area was identified. Furthermore, the water body was estimated from the NDVI data of 2005 and 2015, which have been validated for vegetation assessment. The results of the Landsat data use study indicated a decrease in the dense vegetation area that has led to widespread drought conditions in some parts of the watershed.KeywordsLandsat imageQGISLand use/Land coverNDVIBuffer technique