Abstract:
Objectives The loess plateau is an important agricultural and ecological barrier region in China, but agricultural activities in this area have long been plagued by problems such as water scarcity. The implementation of large-scale water conservancy projects can help address the shortage of irrigation water. However, such projects may also trigger secondary disasters, such as land subsidence. These disasters pose a significant threat to agricultural production activities. Nevertheless, few studies have quantitatively assessed the impact of large-scale water conservancy projects on land subsidence in the agricultural areas of the Loess Plateau.
Methods The research focused on Baicaoyuan in Huining County, Gansu Province,China，applying small baseline subsets interferometric synthetic aperture radar technology. It involved the analysis of seven scenes of advanced land observation satellite PALSAR and 472 Sentinel-1A images to monitor and analyze surface deformation over a period of 17 years. Through K-means clustering analysis and wavelet transformation, an in-depth exploration of the time series of land subsidence was conducted to identify the subsidence patterns in different areas of Baicaoyuan, and to analyze their relationship with land use and rainfall.
Results The research found that the annual surface deformation rate in Baicaoyuan fluctuated from -17 to 0 mm/a between 2007 and 2010. This rate increased significantly between -110 and 30 mm/a from 2015 to 2023. This change suggests a substantial trend of enhanced ground subsidence following the commencement of the 2014 Yintao Project.
Conclusions Land subsidence in the Baicaoyuan area is primarily concentrated in cultivated and grassland areas. The irrigation from the Yintao Project is the leading factor contributing to the land subsidence in the region, and there is a certain correlation with rainfall factors during the period from 2018 to 2020.
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