A novel knowledge base method in Riparian Buffer Zone (RBZ) delineation with remote sensing imagery

Abstract

The importance of Riparian Buffer Zones (RBZs) on riverine landscapes has recently received growing attention, which has led to studying, mapping, and monitoring RBZs areas. Additionally, several studies have examined their influence on water quality, vegetation cover, wild life, sediment, and pollution sources. The Riparian Buffer Zones, which are terrestrial areas located between fluvial water bodies and land, provide several ecosystem services and have a rich biodiversity. The present study aimed to identify and monitor the Riparian Buffer Zones in the Gorganroud basin which is located in the north of Iran and south eastern side of the Caspian Sea. This region is one of the largest basins and one of the most precious regions in Iran due to its humid climate and famous forests. RBZs were monitored in four corners of the basin within three selected sub-basins. Land-use map of the Riparian Buffer Zones was extracted in each part within dense vegetation, low-density vegetation, and water, and the area and percentage of each Buffer class were derived for each sub-basin. Two indexes of NDVI and NDWI were calculated and applied for identifying water and green cover pixels of the region and their dispersion. These two indicators helped extract an accurate map of the buffer zones. The results showed that the water buffer area in the north part was significant in comparison with the southern and eastern parts, which could be due to due to more rice fields. Furthermore, low-density vegetation was higher in the south since it is a mountainous area. Further, dense vegetation was high in the center of the watershed due to forests, which was confirmed by the NDVI index.