Documenting recent human influences using remote sensing techniques on the Tekes River alluvial fan, Xinjiang, China

Abstract

The Tekes River alluvial fan is located in Xinjiang Province which has an arid to semi-arid climate as well as a historically unpredictable precipitation rate. Further, increasing population and urbanization means that all water resources must be used efficiently. The Tekes River alluvial fan has had a vast amount of human influence in recent decades in the form of dam construction, irrigation and agriculture expansion. Although development on and surrounding the Tekes River alluvial fan is apparent, there is a lack of research on how these human impacts have affected the fan. The primary objective of this project is to use remotely sensed image analysis to document the human influence that has occurred to the Tekes River alluvial fan. A 31-year time series (1990-2021) was created using Landsat imagery from 1990 – 2021. The results have found that four dams have been constructed upstream from the fan, irrigation canal length had increased by approximately 400 km, and agricultural fields had increased by approximately 250 km2 between 1990 to 2021. Average seasonal NDVI values were calculated on agricultural fields and compared to natural vegetation in the area for seven dates in 2021. The results do not show great observable differences between agricultural field and natural vegetation cover. However, these results are limited temporally and spatially. It is possible that human influence will be affected seasonal NDVI variation on the fan but there has not been enough time between development and the time of the research. Further research should continue to document and test NDVI as well as consider measuring groundwater levels to build upon this research and provide a greater understanding of the anthropogenic impacts on the fan.