Earth fissures associated with groundwater withdrawal are complex products of both human activities and natural forces, and they occur in definable geological environments. In this paper, the authors first characterize the driving forces for earth fissures caused by groundwater withdrawal. Then, the effects of various factors, such as stresses and pre-existing geological structures, are examined using conceptual models. Numerical results show that the fissuring process is controlled not only by the induced movement at depth and pre-existing structures but also by the in situ stress field. In addition, the degree to which aquifer movement and pre-existing structures actually trigger fissuring depends greatly on the in situ stress field. The authors conclude that earth fissuring related to groundwater withdrawal is a multi-step process that is influenced by a multiplicity of factors, one being the aquifer movement. With groundwater withdrawal, hydraulic and gravitational forces tend to drive aquifer material to deform both horizontally and vertically. Cumulative deformation or strain results in movement. In turn, this aquifer movement results in differential displacements at depth along planes of weakness, such as pre-existing faults and material interfaces. This differential movement (both horizontal and vertical) then generates tensile zones at depth. Once formed, such a tensile zone may migrate upward, form a crack (fail) where the vadose zone is brittle, and eventually express itself as an earth fissure at the land surface in arid or semi-arid regions. In humid regions, the same tensile zone (lateral stretching) at depth will simply express itself as a transient sub-vertical plane of enhanced porosity within and crossing the vadose zone.

The increasing conflicts for water resources between upstream and downstream regions appeal to chronological insight across the world. While the negative consequence of downstream water scarcity has been widely analyzed, the quantification of influence of upstream water use on downstream water scarcity has received little attention. Here non-anthropologically intervened runoff (natural runoff) was first reconstructed in upstream, middle stream and downstream regions in China's 12 large basins in the 1970s to 2000s time period using the Fu–Budyko framework, and then compared to the observed data to obtain the developmental trajectories of water scarcity, including the ratio of water use to availability (WTA) and the per capita water availability (FI; Falkenmark Index) on a decadal scale. Furthermore, a contribution analysis was used to investigate the main drivers of water scarcity trajectories in those basins. The results show that China as a whole has experienced a rapid increase of WTA stress with surface water use rapidly increasing from 161 billion cubic meters (12 % of natural runoff) in the 1970s to 256 billion cubic meters (18 %) in the 2000s, with approximately 65 % increase occurring in northern China. In the 2000s, the increase of upstream WTA stress and the decrease of downstream WTA stress occurred simultaneously for semi-arid and arid basins, which was caused by the increasing upstream water use and the consequent decreasing surface water use in downstream regions. The influence of upstream surface water use on downstream water scarcity was less than 10 % in both WTA and FI for humid and semi-humid basins during the study period, but with an average of 26 % in WTA and 32 % in FI for semi-arid and arid basins. The ratio increased from 10 % in the 1970s to 37 % in the 2000s for WTA and from 22 % in the 1980s to 37 % in the 2000s for FI. The contribution analysis shows that the WTA contribution greatly increases in the 2000s mainly in humid and semi-humid basins, while it decreases mainly in semi-arid and arid basins. The trajectories of China's water scarcity are closely related to socioeconomic development and water policy changes, which provide valuable lessons and experiences for global water resources management.

Groundwater is a critical resource for sustainable economic growth in an arid and semi-arid region such as the Rio Grande Basin because it provides water for municipal, industrial, and domestic, and ...