Environmental change characterization and analysis of rivers' islands: a study from sudan- tuti island during the period 1975-2017: remote sensing and gis perspective

This paper intends to study the environmental change characterization and analyses river islands with special emphasis on Tuti island area. Also, the article attempts to explore the change causes during the period 1975-2017, identifies its nature and assesses its spatial pattern, using remote sensing and GIS approaches. The main sources of data are the remote sensing images of Tuti Island (Spatial and Temporal images) for the years 1975, 1987, 2000, 2010 and 2017). The software used for data analysis is ArcGIS and Eardas Imagine. An accuracy assessment for images and results was conducted for the purpose of validation. Field survey was carried out for ground truth. Results showed that Tuti Island has witnessed an increase and decrease during the period 1975-2017,which proposed that Tuti Island has characterized by dynamic changes over time. During "1975-1987" the total area of Tuti Island increased by 11.6%, most probably due to flood events of 1988 which sediments deposited on the island surfaces area and edges. However, during 1987-2017, Tuti Island area slightly decreased by 0.83% at the minimum level and by 1.63% at the maximum level. The variation in the area is a result of the White Nile and Blue Nile deposition as well as anthropogenic factors. The results also showed that Tuti Island has a typical crescent shape with a very narrow coastal plain; these spatial attributes are an outcome of an annual deposition of silt forming a small strip of fluvial landform as a distinctive geomorphological feature of the island. Water erosion (Haddam) affects most of its agricultural areas on the rivers’ banks of Tuti Island. Significant changes from agricultural area to a residential area were seen during 1975-2017; thus, indicating that many of the potential changes will not only be harmful to ecosystems and human societies, but will also be costly to deal with, both socially and economically.