Assessment of Encroachment along the Urban River using Unmanned Ariel Vehicle

Abstract Streams and rivulets have a significant contribution to maintain river networks and their hydrology. It plays a crucial role in shaping downstream ecosystems and connecting watersheds. Despite their importance, these smaller rivers often lack the legal protections afforded to larger river segments, leaving them vulnerable to encroachment and changes in land use. The Assi River, a minor tributary of the river Ganga, once a historical lifeline and cultural symbol, is currently facing a severe threat to its existence. Due to illegal construction and encroachments, a substantial part of the river Assi has been transformed into a narrow channel carrying the municipal load of the city. The study, embraced encroachment and land use analysis in different buffer widths in high resolution scale. A UAV (DJI Phantom 4) was used to collect the aerial imagery and data was processed using Pix4D Mapper 4.1.2 to produce ortho-photo and DSM having horizontal accuracy of 5 cm. The land use and encroachment have been analysed using processed UAV images on QGIS.