Seasonal subsidence and rebound in Las Vegas Valley, Nevada, observed by Synthetic Aperture Radar Interferometry

Abstract

Analyses of areal variations in the subsidence and rebound occurring over stressed aquifer systems, in conjunction with measurements of the hydraulic head fluctuations causing these displacements, can yield valuable information about the compressibility and storage properties of the aquifer system. Historically, stress-strain relationships have been derived from paired extensometer/piezometer installations, which provide only point source data. Because of the general unavailability of spatially detailed deformation data, areal stress-strain relations and their variability are r•ot commonly considered in constraining conceptual and numerical models of aquifer systems. Interferometric synthetic aperture radar (InSAR) techniques can map ground displacements at a spatial scale of tens of meters over 100 km wide swaths. InSAR has been used previously to characterize larger magnitude, generally permanent aquifer system compaction and land subsidence at yearly and longer timescales, caused by sustained drawdown of groundwater levels that produces intergranular stresses consistently greater than the maximum historical stress. We present InSAR measurements of the typically small-magnitude, generally recoverable deformations of the Las Vegas Valley aquifer system occurring at seasonal timescales. From these we derive estimates of the elastic storage coefficient for the aquifer system at several locations in Las Vegas Valley. These high-resolution measurements offer great potential for future investigations into the mechanics of aquifer systems and the spatial heterogeneity of aquifer system structure and material properties as well as for monitoring ongoing aquifer system compaction and land subsidence. Papernumber 2000WR900404. 0043-1397/01/2000WR900404 $09.00 mainder was met with water imported from Lake Mead. In the central part of the valley, declining heads in the aquifer system incorporating thick, highly compressible clay beds (aquitards) have led to subsidence rates of several centimeters per year during most of the 20th century, with resulting damage to structures and well casings. Differential subsidence has reactivated existing Quaternary faults and created new earth fissures [Bell and Price, 1991]. Recently, artificial recharge has become an increasingly important tool to mitigate the negative effects of land subsidence due to overdrafting of the aquifer system in Las Vegas [Pavelko et al., 1999].Subsidence in the Las Vegas area has previously been monitored using precise leveling surveys and a borehole extensometer installation, the Lorenzi site, that was installed in 1994

Subsidence Evolution of the Leizhou Peninsula, China, Based on InSAR Observation from 1992 to 2010

“…Whether the location of maximum subsidence corresponds to the location of lowest groundwater level is an interesting question and it can help us understand the mechanism of land subsidence caused by groundwater pumping. The rapid declining level of the middle and deep aquifers can result in land subsidence due to the damage to the balance of the hydraulic structure [33,34]. In Zhanjiang city, the water level of middle-deep and deep aquifers started declining in the late 1980s and resulted in two obvious subsidence zones centered on XiaShan district [2,32] until 2001.…”

“…Moreover, unguided drilling, such as mixed exploitation of water from shallow-and deep-aquifers [35], and illegal drilling both accelerated the shrinking of groundwater level and caused a wide range of land subsidence. The bowl in Figure 10a (marked Subsiding areas shown in Figure 10a are farmlands characterized with highly compressible deposits, consisted of clay, silt, and silty sand (see Figure 2a), which is vulnerable to land subsidence due to sediment loading [8,33,34]. Shallow aquifers are the main supplier of these agricultural areas, which can be recharged seasonally from surface runoff, such as reservoirs and canals.…”

Geomechanical response to seasonal gas storage in depleted reservoirs: A case study in the Po River basin, Italy

“…Differential interferometric synthetic aperture radar (DInSAR)-based techniques have allowed for measurement with an impressively high resolution and accuracy of the seasonal land subsidence and rebound caused by cyclic aquifer system pumping and recharge [Hoffmann et al, 2001;Schmidt and Bürgmann, 2003;Bell et al, 2008]. Typically, the vertical component u z of the ground surface motion is resolved.…”

Methods for monitoring land subsidence and earth fissures in the Western USA

“…The principal of interferometry is described by Gabriel and Goldstein (1988) and there are numerous examples of applying the InSAR methodology to characterizing land subsidence where Hoffmann et al (2001) and Panda et al (2013) provide good examples. Interferometry has the ability to detect and quantify minute changes in the elevation of terrain by comparing phase variances of satellite-based, side-looking radar data between orbits of a similar trajectory.…”