Measuring Spatiotemporal Features of Land Subsidence, Groundwater Drawdown, and Compressible Layer Thickness in Beijing Plain, China

Yongyong Li,Lin Zhu,Xiaojuan Li,Huili Gong

doi:10.3390/w9010064

Abstract

Beijing is located on multiple alluvial-pluvial fans with thick Quaternary unconsolidated sediments. It has suffered serious groundwater drawdown and land subsidence due to groundwater exploitation. This study aimed to introduce geographical distribution measure methods into land subsidence research characterizing, geographically, land subsidence, groundwater drawdown, and compressible layer thickness. Therefore, we used gravity center analysis and standard deviational ellipse (SDE) methods in GIS to statistically analyze their concentration tendency, principle orientation, dispersion trend, and distribution differences in 1995 (1999), 2007, 2009, 2011, and 2013. Results show that they were all concentrated in Chaoyang District of Urban Beijing. The concentration trend of land subsidence was consistent with that of groundwater drawdown. The principle orientation of land subsidence was SW–NE, which was more similar with that of the static spatial distribution of the compressible layer. The dispersion tendency of land subsidence got closer to that of the compressible layer with its increasing intensity. The spatial distribution difference between land subsidence and groundwater drawdown was about 0.2, and that between land subsidence and compressible layer thickness it decreased from 0.22 to 0.07, reflecting that the spatial distribution pattern of land subsidence was increasingly close to that of the compressible layer. Results of this study are useful for assessing the distribution of land subsidence development and managing groundwater resources.

Highlights

Regional land subsidence is a geological process occurring in a long-run equilibrium and inter-coordination between anthropogenic activity and the hydrogeological environment [1,2]
This paper proposed a comprehensive geographic measurement to improve the understanding of spatiotemporal distribution features of land subsidence, groundwater drawdown, and compressible layer thickness in Beijing Plain
Groundwater drawdown, and compressible layer thickness were all concentrated in Chaoyang District

Summary

Introduction

Regional land subsidence is a geological process occurring in a long-run equilibrium and inter-coordination between anthropogenic activity and the hydrogeological environment [1,2]. Land subsidence in Beijing Plain is mainly triggered by over-exploitation of groundwater, and its magnitude and extent is affected by heterogeneity of compressible layers [21]. The small baseline interferometric synthetic aperture radar (InSAR) [24] technique was employed to investigate the relationship between land subsidence and groundwater level, active faults, cumulated soft soil thickness, different aquifer types, and the distance to pumping wells [10]. These studies proved that the spatial extent and magnitude of land subsidence in Beijing Plain has both spatial variability and inheritance. They paid much attention to adopting a GIS spatial overlay or visualization, focusing on its spatial extent, magnitude, and spatial correlation with groundwater drawdown, and the geological structural control at the macro scale, but it has been rarely reported that Geographic Distribution

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Results

Discussion

Conclusion