395

15

40

58

247

58

15

Barstow

Victorville

San Bernardino

Lucerne

Valley

San Bernardino Mountains

San Gabriel Mountains

Granite

Mtns

Ord Mtns

Lucerne Valley

Mojave

Desert

Mojave

Valley

Calico Mtns

Black Mtn

Johnson

Valley

Newberry Mtns

Rodman Mtns

SANTA ANA RIVER

El Mirage

Dry Lake

Harper

Dry Lake

Coyote

Dry Lake

Troy

Dry Lake

Lucerne

Dry Lake

MOJAVE RIVER N

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2017–3053

Printed on recycled paper July 2017

Land Subsidence in the Southwestern 

Mojave Desert, California, 1992–2009

In cooperation with the Mojave Water Agency (MWA), the U.S. Geological Survey (USGS) has been 

monitoring land subsidence in the southwestern Mojave Desert of California using satellite Interferometric 

Synthetic Aperture Radar (InSAR) combined with ground-based techniques. Maps of land subsidence 

constructed from the InSAR data have proven to be an economical means to evaluate subsidence—with 

the goal of identifying small problems before they become large ones. The maps of subsidence over the 

considerably large (nearly 5,000 square miles [mi2]) MWA management area (fig. 1) enabled researchers to 

detect small magnitude, localized areas of subsidence near five lakebeds. 

Introduction and Background

Groundwater has been the primary source of domestic, 

agricultural, and municipal water supplies in the southwestern 

Mojave Desert, California, since the early 1900s. Increased 

demands on water supplies have caused groundwater-level 

declines of more than 100 feet (ft) in some areas of this desert 

(fig. 2 inset) between the 1950s and the 1990s (Stamos and 

others, 2001; Sneed and others, 2003). These water-level 

declines have caused the aquifer system to compact, resulting 

in land subsidence. Differential land subsidence (subsidence 

occurring at different rates across the landscape) can alter 

surface drainage routes and damage surface and subsurface 

infrastructure. For example, fissuring across State Route 247 

at Lucerne Lake (fig. 2) has required repairs as has pipeline 

infrastructure near Troy Lake. 

Land subsidence within the Mojave River and Morongo 

Groundwater Basins of the southwestern Mojave Desert has 

been evaluated using InSAR, ground-based measurements, 

geology, and analyses of water levels between 1992 and 2009 

(years in which InSAR data were collected). The results of the 

analyses were published in three USGS reports—

Sneed and others (2003), Stamos and others 

(2007), and Solt and Sneed (2014). 

Results from the latter 

two reports were 

integrated with results from other USGS/ MWA cooperative 

groundwater studies into the broader scoped USGS Mojave 

Groundwater Resources Web site (http://ca.water.usgs.gov/

mojave/). This fact sheet combines the detailed analyses from the 

three subsidence reports, distills them into a longer-term context, 

and provides an assessment of options for future monitoring. 

InSAR Reveals Localized Subsidence near Dry Lakebeds

InSAR data and field observations reveal land subsidence 

during 1992–2009 in five localized areas near dry lake beds— El 

Mirage Lake, Harper Lake, Troy Lake, Coyote Lake, and Lucerne 

Lake (fig. 2). Average subsidence rates at Harper, Troy, and Coyote 

Lakes, were smallest at about 0.3–0.4 inch per year (in/ yr), El 

Mirage Lake had a slightly higher rate at nearly 0.5 in/yr, and 

Lucerne Lake had the highest rate of about 0.6 in/yr. Only two 

of the areas—Troy Lake and Lucerne Lake—indicated increased 

subsidence rates starting in the late 1990s or early 2000s, which may 

reflect changes in agricultural land use and (or) a population increase 

that require more water use, whereas the other three areas subsided 

at fairly steady rates. 

Figure 1. National Agriculture Imagery Program (NAIP) imagery 

from 2012 overlain with dry lakebeds, Mojave Water 

Agency management area, and other features 

in the Mojave Desert, California.
395

395

15

15

40

40

58

58

15

247

247

62

Barstow

Victorville

Lucerne

Valley

22R5

10E1

~2 inches

subsidence

Troy Lake

July 2004 - November 2009

30N1

28R2 ~1.5 inches

subsidence

Harper Lake

July 2004 - November 2009

10P2

23C3

~1.5 inches

subsidence

El Mirage Lake

May 2005 - May 2009

36F5

~3 inches

subsidence

Lucerne Lake

July 2004 - November 2009

36F1

25G1

26R1

32G2

~2 inches

subsidence

Coyote Lake

July 2004 - November 2009

26R1

El Mirage

Lake

Harper

Lake

Coyote

Lake

Troy

Lake

Lucerne

Lake

MOJAVE RIVER

SCIA

P606

P588

P583

P582

P470

LDES

HAR7

GMAG

CTMS

BSRY

AVRY

SDHL

10P2

32G2

30N1 26R1

22R5

10E1

23C3

36F1

25G1

36F5

28R2

5 15 MILES

5 10

0 10

0 15 KILOMETERS

EXPLANATION

Approximate location of fissures

Continuous GPS site and name

Well and name (symbol colors match 

 hydrograph colors)

Mojave Water Agency management area

Morongo Groundwater Basin

Mojave River Groundwater Basin

36F5

36F1

P588

Figure 2. Study area and boundaries of selected groundwater 

basins, the Mojave Water Agency management area, and 

other features. Insets show typical subsidence extents near 

dry lake beds—El Mirage Lake, Harper Lake, Troy Lake, 

Lucerne Lake, and Coyote Lake—and a hydrograph of water 

levels near Lucerne Lake. Subsidence generally occurred 

near the eastern edge of Harper Lake, western edge of Troy 

Lake, near the southern edges of Coyote Lake and El Mirage 

Lake, and south of Lucerne Lake.

CALIFORNIA

0

20

40

60

80

100

120

140

1950 1960 1970 1980 1990 2000 2010

Water level, in feet

below land surface 

25G1 (site ID: 342943116555201)
El Mirage Lake

Observations

• More than 6 inches (in.) of subsidence occurred at a fairly 

steady rate of nearly 0.5 in/yr during 1995–2009. 

• Water levels generally declined by small to moderate amounts 

in shallow and deep wells during the 1990s and 2000s.

• Historical groundwater levels (prior to the 1980s) are not 

known, although simulations indicate water-level declines 

since the 1930s (Stamos and others, 2001). 

• Clay layers ranging from 5 to 295 ft in thickness are present in 

the shallow and deep parts of the aquifer system. 

Results

• Concurrent and residual compaction throughout the aquifer 

system are both likely because water levels were declining 

and thin and thick clay layers are present. 

• Historical (simulated) and current (measured) water-level 

declines suggest that water levels were likely at or near 

historically low levels, indicating that at least some of the 

compaction is permanent.

0

2

4

6

8

10

12

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 

Subsidence, in inches 

30

40

50

290

300

310

320

330

340

Water level, in feet below land surface

EXPLANATION

43.77 feet

329.6 feet

Lowest recorded

well water level

23C3 (343555117351202)—700 feet 

10P2 (343712117361701)—320 feet

Well no. (site ID) and depth

InSAR

Subsidence

Estimated 

subsidence

 Harper Lake

Observations

• More than 6 in. of subsidence occurred at a fairly steady rate of 

about 0.4 in/yr during 1992–2009. 

• Water levels generally declined in shallow wells to historically 

low levels since the 1950s, although deep wells generally 

recovered after reaching historically low levels in the 1980s. 

• Clay layers ranging from 8 to 89 ft in thickness are present in the 

shallow and deep parts of the aquifer system. 

Results

• Concurrent and residual compaction in the shallow parts of the 

aquifer system are likely because water levels were declining 

and thin and thick clay layers are present. 

• If compaction has occurred in the deep parts of the aquifer 

system, it likely is residual because water levels (at depth) 

were recovering and both thin and thick clay layers are 

present. 

• At least some compaction that may have occurred in the 

shallow parts of the aquifer system is permanent because 

water levels have persistently declined. 

0

2

4

6

8

10

12

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 

Subsidence, in inches 

50

60

70

80

90

Water level, in feet below land surface

190

200

210

220

230

EXPLANATION

82.4 feet

223.18 feet

Lowest recorded

well water level

30N1 (350050117204901)—500 feet 

28R2 (350039117112101)—223 feet

Well no. (site ID) and depth

InSAR

Estimated 

subsidence

Subsidence

Troy Lake

Observations

• About 5 in. of subsidence occurred at an average rate of 

about 0.3 in/yr during 1993–2009.

• Subsidence rates increased from about 0.15 in/yr during 

1993–99 to nearly 0.45 in/yr during 2004–09.

• Water levels fluctuated seasonally but declined persistently 

to historically low levels in shallow and deep wells since the 

1950s.

• Clay layers ranging from 3 to 100 ft in thickness are present in 

the shallow and deep parts of the aquifer system.

Results

• Concurrent and residual compaction throughout the aquifer 

system are both likely because water levels were declining 

and thin and thick clay layers are present. 

• Persistent water-level declines in shallow and deep wells 

indicate that the compaction likely is permanent.

36.13 feet

125.64 feet

Lowest recorded

well water level

22R5 (345104116384002)—510 feet 

10E1 (344810116331201)—180 feet

Well no. (site ID) and depth

InSAR

Estimated 

subsidence

Subsidence

0

2

4

6

8

10

12

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 

Subsidence in inches 

90

100

110

120

130

40

30

20

50

60

70

80

Water level, in feet below land surface

EXPLANATION
Coyote Lake

Observations

• About 2 in. of land subsidence occurred at a fairly steady

rate of about 0.4 in/yr during 2004–09; subsidence was not

detected prior to 2004.

• Water levels persistently declined small amounts to historically

low levels throughout the aquifer system during 1992–2009.

• Historical water levels in the shallower parts of the aquifer

system have declined small amounts since the 1950s;

historical water levels in the deeper parts of the aquifer 

system are not known. 

• Clay thickness is not known.

Results

• Sparse water level and lithological data hindered

interpretations regarding the timing or permanence of

compaction.

• The absence of substantial water-level declines in the

shallower parts of the aquifer system suggests that

compaction may be occurring deeper in the system.

Lucerne Lake

Observations:

• Nearly 11 in. of subsidence occurred at an average rate of

about 0.6 in/yr during 1992–2009.

• Subsidence rates increased from about 0.5 in/yr during

1992–99 to about 0.7 in/yr during 1999–2009.

• Water levels declined to historically low levels in shallow

wells and recovered in deep wells during 1998–2009

(historical water levels at depth are not known).

• Clay ranging from 20 to 40 ft in thickness is present in shallow

parts of the aquifer system, but no clay was detected at

depth. 

• Fissures that trend northeast to southwest (consistent with

extensional features near the margins of subsiding areas)

have been observed southeast of Lucerne Lake. These 

fissures have caused damage to State Route 247.

Results:

• Concurrent and residual compaction in the shallow aquifer

system may have occurred because of water-level declines

of more than 100 ft since the 1950s and the presence of 

thick, loosely compacted clay layers. 

• Compaction likely has not occurred in the deeper parts of the

aquifer system because of the absence of clay at depth.

• At least some compaction that may have occurred in the

shallow parts of the aquifer system likely is permanent

because water levels have persistently declined by more 

than 100 ft to historical lows (fig. 2 inset).

• Fissures likely were caused by localized differential

subsidence—more subsidence occurred to the southeast

than to the northwest of the fissures.

• The largest subsidence magnitude observed in the study

area coincides with the largest water-level declines where

shallow and thick clay layers may be highly compressible 

because of less overburden from overlying sediments.

0

2

4

6

8

10

12

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 

Subsidence in inches 

Water level, in feet below land surface

50

60

0

10

20

30

40

70

80

90

100

5.54 feet

56.63 feet

Lowest recorded

well water level

26R1 (350036116435601)—109 feet 

32G2 (350531116472501)—? feet

Well no. (site ID) and depth

InSAR

Subsidence

EXPLANATION

“?” indicates well depth is 

 not known

0

2

4

6

8

10

12

1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 

Subsidence in inches 

Water level, in feet below land surface

80

90

100

110

120

130

140

150

160

170

EXPLANATION

InSAR

Estimated 

subsidence

Subsidence

102.35 feet

132.67 feet

Lowest recorded

well water level

36F1 (342850116562301)—744 feet 

36F5 (342850116562305)—134 feet

Well no. (site ID) and depth

Fissures on the southeastern edge of Lucerne Lake (see 

figure 2 for location) in San Bernardino County, Mojave 

Desert, California. View to the northeast, with 5-gallon 

bucket (circled) for scale. Photograph by Loren Metzger, 

U.S. Geological Survey, May 2001.
Fissure near Lucerne Lake along State Route 247 (visible 

in background). Photograph by Michelle Sneed, 

U.S. Geological Survey.

Repairs to State Route 247 after fissures near Lucerne Lake damaged the 

road surface. Photograph by Michelle Sneed, U.S. Geological Survey.

What Caused the Localized Subsidence?

The localized subsidence in the five areas was caused by 

declining water levels in fine-grained (clay and silt) sediments. 

In the Mojave River and Morongo Groundwater Basins (fig. 2), 

the combination of variable climatic conditions, tectonic 

activity, and other factors resulted in complex depositional 

patterns of clay in the subsurface, which, combined with 

water-level declines, define the lateral extent and magnitude 

of subsidence. The deposition of highly compressible paleolakebed deposits occurred at variable rates depending in part 

on climatic conditions. For example, 

wetter conditions lead to a faster pace 

of deposition and thus thicker clay 

deposits such as those at Lucerne 

Lake, whereas drier conditions lead 

to a slower pace of deposition and 

thinner clay deposits, typical of Troy 

Lake. Deposition centers migrated or 

oscillated in response to depositional 

and tectonic activity (Motts, 1969). 

Putting It All Together

Subsidence caused by aquifersystem compaction can be recoverable 

or permanent, and even at a single 

location both types of compaction 

can occur simultaneously at different 

depths. Nearly all alluvial aquifer 

systems, where groundwater levels 

fluctuate, will respond by compacting 

and expanding small amounts that are 

recoverable, but fine-grained aquifer 

systems, where groundwater levels 

persistently decline past historical 

lows may compact permanently 

(Galloway and others, 1999).

The timing of compaction associated with water-level 

declines is important to understand when considering subsidence 

management strategies. For instance, if compaction stopped 

soon after water levels stabilize or begin to recover (concurrent), 

different management strategies would be needed than if 

compaction continued after water levels stabilize or begin to 

recover (residual). Given an equivalent water-level decline, the 

thicker a clay deposit, the longer residual compaction is likely to 

continue after water levels stabilize or recover.

Integrating subsidence, groundwater level, and lithological 

data can help scientists discern 

if the subsidence is recoverable 

or permanent as well as if the 

compaction is concurrent or 

residual. Determining depth 

intervals at which water levels have 

declined and inter-bedded clay 

deposits exist provides information 

for targeting subsidence mitigation 

measures. Determining the 

thickness of clay deposits also is 

important for estimating planning 

horizons of mitigation measures. 

Furthermore, determining the 

historical low groundwater 

level will help estimate critical 

water-level thresholds at which 

permanent subsidence is likely to 

occur.

In the Harper, Troy, and 

Lucerne Lake areas, analyses 

indicate that both concurrent and 

residual compaction may have 

occurred and that at least some of 

the subsidence is permanent. In all 

three of these areas, determining 

the relative contributions of 

concurrent and residual compaction 

was not possible because available data indicated persistent 

water-level declines in shallow wells and subsidence. Frequent 

measurements of water levels and subsidence under conditions 

that include periods of water-level recovery may improve 

the understanding of subsidence mechanisms—if subsidence 

occurs as groundwater levels recover, then it can be attributed to 

residual compaction. 

In the El Mirage and Coyote Lake areas, less is understood 

about the subsidence mechanisms because less data were 

available. Historical (simulated) and recent (measured) waterlevel declines at El Mirage Lake indicate that at least some of 

the observed compaction may be permanent because water levels 

are likely at or near historical lows, and available lithology data 

suggest that concurrent and residual compaction likely occurred. 

Historical water-level and lithologic data were insufficient for 

Coyote Lake, making the subsidence mechanisms of this area the 

least well understood.
Future Monitoring

It is important to continue monitoring groundwater 

levels and land subsidence in the southwestern Mojave Desert 

because water-level declines and subsidence are expected 

to persist. Subsidence has accelerated in some places such 

as near Lucerne and Troy Lakes, which in part, may reflect 

an increase in water use tied to changes in agricultural land 

use or population. InSAR can be used to develop detailed 

seasonal, annual, and multi-annual subsidence maps of the five 

areas discussed herein and to identify previously unknown 

subsidence throughout the nearly 5,000-mi2 MWA management 

area. Where detailed studies are of interest, InSAR can be 

used to site ground-based single or networked extensometer 

or Global Positioning System (GPS) monitoring stations. As 

of 2017, InSAR-capable satellites are routinely collecting data 

over the area—with additional satellites planned—making the 

future of InSAR data availability promising. 

Continuous GPS (CGPS) site (P582) is one of 13 sites in the study area that 

collected position data in 2016 and can be used to evaluate subsidence. 

Daily data from a CGPS site and spatially detailed data from InSAR can 

be leveraged to improve the understanding of compaction processes in 

time and space. Photograph courtesy of University NAVSTAR Consortium 

(UNAVCO), copyright 2006 UNAVCO, Inc. (used with permission).

Coordinating groundwater-level and subsidence monitoring, 

in both time and space, could improve the understanding of the 

mechanisms that drive compaction. Ideally, water levels would 

be measured in wells (with known construction) often enough 

to capture water level highs and lows at seasonal, annual, and 

multi-annual scales, and compared to subsidence measurements 

at similar timescales. As new wells are drilled, detailed logging 

of subsurface lithology would improve the delineation of the 

depths and thicknesses of clay deposits. Currently (2016), 

13 continuous GPS (CGPS) sites are located in the MWA 

management area (fig. 2), but generally are distant from areas 

of known subsidence, or have a period of record too limited to 

have been useful for the 1992–2009 study period. Extensometers 

currently are the only tools that can measure compaction at 

depth-specific intervals, and have not been installed in the MWA 

management area (InSAR and CGPS measure subsidence at 

the land surface). When coupled with co-located water-level 

measurements, extensometer measurements can be used to 

analyze the aquifer-system response to water-level changes at 

specific depth intervals. This information can lead to a better 

understanding of the storage properties of the aquifer, thereby 

improving simulations of groundwater flow and subsidence, and 

facilitate the consideration of land subsidence as a constraint in 

evaluation of water-resource management strategies. 

Areal imagery of the Harper Lake area showing center pivot farms in 2007 

(left, near infrared false-color image) that were converted to solar fields by 

2015 (right). Land-use changes such as those illustrated above require less 

water and may help explain some of the water-level recovery observed in 

this area. Images provided by Mojave Water Agency (used with permission).

References Cited

Galloway, D.L., Jones, D.R., and Ingebritsen, S.E., 1999, Land 

subsidence in the United States, 1999: U.S. Geological Survey 

Circular 1182, http://pubs.er.usgs.gov/publication/cir1182.

Motts, W.S., ed., 1969, Geology and hydrology of selected playas in 

Western United States: Amherst, University of Massachusetts, 305 p.

Sneed, Michelle, Ikehara, M.E., Stork, S.V., Amelung, Falk, and 

Galloway, D.L., 2003, Detection and measurement of land 

subsidence using interferometric synthetic aperture radar and 

global positioning system, San Bernardino County, Mojave Desert, 

California: U.S. Geological Survey Water-Resources Investigations 

Report 03-4015, 60 p.

Solt, Mike, and Sneed, Michelle, 2014, Subsidence (2004–2009) in 

and near lakebeds of the Mojave River and Morongo groundwater 

basins, southwest Mojave Desert, California: U.S. Geological Survey 

Scientific Investigations Report 2014-5011, unpaginated, http://

dx.doi.org/10.3133/sir20145011.

Stamos, C.L., Glockhoff, C.S., McPherson, K.R., and Julich, R.J., 2007, 

Water-level and land-subsidence studies in the Mojave River and 

Morongo groundwater basins: U.S. Geological Survey Scientific 

Investigations Report 2007-5097, unpaginated, http://pubs.usgs.gov/

sir/2007/5097/.

Stamos, C.L., Martin, Peter, Nishikawa, Tracy, and Cox, B.F., 2001, 

Simulation of ground-water flow in the Mojave River Basin, 

California (ver. 3, September 2001): U.S. Geological Survey WaterResources Investigations Report 2001-4002, 137 p.

Authors: Justin Brandt and Michelle Sneed

For more information: U.S. Geological Survey

6000 J Street, Placer Hall,

 California State University, Sacramento

 Sacramento, CA 95819

https://ca.water.usgs.gov/mojave

Publishing support provided by the U.S. Geological Survey, 

Tacoma Publishing Service Center

Design: William Gibbs

ISSN 2327-6916 (print)

ISSN 2327-6932 (online)

https://doi.org/10.3133/fs20173053