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Age Determination of the Remaining Peat in the Sacramento–San Joaquin Delta, California, USA

U.S. Geological Survey (USGS) | October 9th, 2007

Summary

The Sacramento–San Joaquin Delta of California was once a 1,400 square kilometer (km2) tidal marsh, which contained a vast layer of peat ranging up to 15 meters (m) thi

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Analysis and simulation of regional subsidence accompanying groundwater abstraction and compaction of susceptible aquifer systems in the USA

Boletín de la Sociedad Geológica Mexicana | January 17th, 2013

Summary

Regional aquifer-system compaction and land subsidence accompanying groundwater abstraction in susceptible aquifer systems in the USA is a challenge for managing groundwa

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Detection and Measurement of Land Subsidence Using Global Positioning System Surveying and Interferometric Synthetic Aperture Radar, Coachella Valley, California, 1996–2005

U.S. Geological Survey (USGS), Coachella Valley Water District | June 13th, 2013

Summary

Land subsidence associated with ground-water-level declines has been investigated by the U.S. Geological Survey in the Coachella Valley, California, since 1996. G

Land subsidence associated with ground-water-level declines has been investigated by the U.S. Geological Survey in the Coachella Valley, California, since 1996. Groundwater has been a major source of agricultural, municipal, and domestic supply in the valley since the early 1920s. Pumping of ground water resulted in water-level declines as large as 15 meters (50 feet) through the late 1940s. In 1949, the importation of Colorado River water to the southern Coachella Valley began, resulting in a reduction in ground-water pumping and a recovery of water levels during the 1950s through the 1970s. Since the late 1970s, demand for water in the valley has exceeded deliveries of imported surface water, resulting in increased pumping and associated ground-water-level declines and, consequently, an increase in the potential for land subsidence caused by aquifer-system compaction. Global Positioning System (GPS) surveying and interferometric synthetic aperture radar (InSAR) methods were used to determine the location, extent, and magnitude of the vertical land-surface changes in the southern Coachella Valley. GPS measurements made at 13 geodetic monuments in 1996 and in 2005 in the southern Coachella Valley indicate that the elevation of the land surface had a net decline of 124 to 9 mm ±54 mm (0.41 to 0.03 ft ±0.18 ft) during the 9-year period. Changes at 9 of the 13 monuments exceeded the maximum expected uncertainty of ±54 mm (±0.18 ft) at the 95-percent confidence level, indicating that subsidence occurred at these monuments between June 1996 and August 2005. GPS measurements made at 20 geodetic monuments in 2000 and in 2005 indicate that the elevation of the land surface changed –192 to +51 mm ±36 mm (–0.63 to +0.17 ft ±0.12 ft) during the 5-year period. Changes at 6 of the 20 monuments exceeded the maximum expected uncertainty of ±36 mm (±0.12 ft) at the 95-percent confidence level—subsidence occurred at five monuments and uplift occurred at one monument between August 2000 and August 2005. GPS measurements at two of the five subsiding monuments for which subsidence rates could be compared indicate that subsidence rates decreased during this period compared with subsidence rates before 2000. InSAR measurements made between May 7, 2003, and September 25, 2005, indicate that land subsidence, ranging from about 75 to 180 millimeters (0.25 to 0.59 foot), occurred in three areas of the Coachella Valley: near Palm Desert, Indian Wells, and La Quinta; the equivalent subsidence rates range from about 3 to more than 6 mm/month (0.01 to 0.02 ft/month). The subsiding areas near Palm Desert, Indian Wells, and La Quinta were previously identified using InSAR measurements for 1996–2000, which indicated that about 35 to 150 mm (0.11 to 0.49 ft) of subsidence occurred during the four-year period; the equivalent subsidence rates range from about 1 to 3 mm/month (0.003 to 0.01 ft/month). Comparison of the InSAR results indicates that subsidence rates have increased 2 to 4 times since 2000 in these three areas. Water-level measurements made at wells near the subsiding monuments and in the three subsiding areas generally indicated that the water levels fluctuated seasonally and declined annually between 1996 and 2005; some water levels in 2005 were at the lowest levels in their recorded histories. The coincident areas of subsidence and declining water levels suggest that aquifer-system compaction may be causing subsidence. If the stresses imposed by the historically lowest water levels exceeded the preconsolidation stress, the aquifer-system compaction and associated land subsidence may be permanent. Although the localized character of the subsidence signals is typical of the type of subsidence characteristically caused by localized ground-water pumping, the subsidence may also be related to tectonic activity in the valley.

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Detection of aquifer system compaction and land subsidence using interferometric synthetic aperture radar, Antelope Valley, Mojave Desert, California

U.S. Geological Survey (USGS) | April 15th, 1998

Summary

Interferometric synthetic aperture radar (InSAR) has great potential to detect and quantify land subsidence caused by aquifer system compaction. InSAR maps with h

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Estimating the permanent loss of groundwater storage in the southern San Joaquin Valley, California

American Geophysical Union, Water Resources Research | February 23rd, 2017

Summary

In the San Joaquin Valley, California, recent droughts starting in 2007 have increased the pumping of groundwater, leading to widespread subsidence. In the southern porti

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Factors and Processes Affecting Delta Levee System Vulnerability

San Francisco Estuary & Watershed Science (UC Davis) | December 1st, 2016

Summary

The authors appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils over time has cause

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Ground Water in the Central Valley, California - A Summary Report

U.S. Geological Survey (USGS) | June 1st, 1991

Summary

The agricultural productivity of the Central Valley depends on irrigation. Half of the 22 million acre-feet of irrigation water applied annually is ground water. The va

The agricultural productivity of the Central Valley depends on irrigation. Half of the 22 million acre-feet of irrigation water applied annually is ground water. The valley is a long, narrow structural trough filled with about 32,000 feet of sediment in the south and as much as 50,000 feet in the north. Nearly all the fresh ground water is contained in the continental rocks and deposits younger than Eocene age. Streamflow, an important factor in recharging the aquifer system, is influenced by precipitation in the mountains surrounding the valley. The majority of recharge from infiltration of streamflow occurs on the east side of the valley. Ground-water pumpage, which greatly exceeds the natural recharge rate, has dramatically altered the ground-water flow in the Central Valley. During the 1960's and 1970's, the recharge rate was more than five times that of the predevelopment period and was largely derived from percolation of imported surface water or recirculated pumped ground water rather than precipitation and recharge from streams. Prior to development, most ground water was discharged as evapotranspiration; however, in recent years, most discharge has been well pumpage. Computer simulation of the Central Valley aquifer system suggests that the total flow through the system has increased from about 2 million acre-feet per year to nearly 12 million acre-feet per year. The vertical movement of ground water has been artificially enhanced by many of the 100,000 irrigation wells that contain long intervals of perforated casing. When unpumped, these wells permit vertical flow between permeable layers within the aquifer system. The total fresh ground water presently (1986) in storage in the upper 1,000 feet of the aquifer system is about 800 million acre-feet. During the 1960's and 1970's, ground water in storage was depleted at an average rate of 800,000 acre-feet annually. In the San Joaquin Valley from the 1940's to the late 1960's, substantial withdrawals of ground water were accompanied by hundreds of feet of head decline. This head decline caused inelastic compaction of fine-grained beds, resulting in land subsidence that is unequaled anywhere else in the world. More than one-half of the San Joaquin Valley (or about 5,200 square miles) underwent subsidence of more than 1 foot. In one location, subsidence exceeded 29 feet. Within the areas of heavy withdrawals, subsidence is greatest where the aquifer system contains thick sections of montmorillonite clay. Land subsidence created engineering and economic problems, including damage to canals and drainage systems, and loss of irrigation wells caused by casing failure. More recently (since the drought of 1976-77), surface-water imports have increased, ground-water pumpage has decreased, and in places, ground-water levels have recovered. Land subsidence has virtually ceased; however, it could resume with increased pumpage, if water levels decline below previous lows. Ground-water quality in the Central Valley is generally influenced by the water from streams that are a major source of recharge. In general, water on the east side of the valley and from east-side streams contains low concentrations of dissolved solids compared to water on the west side and from west-side streams. Concentrations of dissolved solids in ground water generally are lower in the northern part of the valley than in the southern part. There are, however, localized exceptions in many places through the valley. Local concentrations of boron, chloride, and nitrate in the ground water of the Central Valley are large enough to be a problem either to crops or humans. Human activities have some influence on the concentration and location of water-quality problems in the valley. Significant increases in concentrations of dissolved solids and, specifically, dissolved nitrate indicate that ground-water quality is degrading as a result of increasing application of fertilizer in agricultural areas and the growth of urban population. Pesticides such as dibromochloropropane (DBCP) as well as selenium and other trace elements in agricultural drainage water cause ecological and health problems in the San Joaquin Valley.

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Hydro-economic analysis of groundwater pumping for irrigated agriculture in California’s Central Valley, USA

Hydrogeology Journal, Springer | July 12th, 2015

Summary

As in many places, groundwater in California (USA) is the major alternative water source for agriculture during drought, so groundwater’s availability will drive some i

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Land subsidence in the San Joaquin Valley, California, as of 1972

U.S. Geological Survey (USGS) | July 10th, 1975

Summary

Land subsidence which began in the mid-1920's due to groundwater overdraft in the San Joaquin Valley has caused widespread concern for the past two decades. Withdrawals

Land subsidence which began in the mid-1920's due to groundwater overdraft in the San Joaquin Valley has caused widespread concern for the past two decades. Withdrawals for irrigation increased from 3 million acre-feet in 1942 to 10 million acre-feet in 1966. Water levels declined at unprecedented rates during the 1950's and early 1960's. Pumping lifts became inordinately high, well casings failed at alarming rates, and differential settlement caused numerous farming and engineering problems. By 1970,5,200 square miles of valley land had been affected, and maximum subsidence exceeded 28 feet. The valley-wide volume of subsidence totaled 15.6 million acre-feet, one-half the initial storage capacity of Lake Mead. This subsidence represents one of the great environmental changes imposed by man. Importation of surface water to the northwestern and eastern areas of overdraft in the valley began in the 1950's and to the much larger western and southern areas in the late 1960's. Canal imports have largely replaced ground-water pumpage in these areas. As of 1973, after three decades of continued declining water levels, many hundreds of irrigation wells are idle and water levels are rising. Throughout much of the valley, artesian pressures are recovering toward their presubsidence levels, and elevations of the subsiding land surface are stabilizing. Basic-data graphs and computer-plotted stress-strain relationships constitute a major part of this report. They are based on 10-13 years of detailed field measurements of both water-level change and compaction collected by the U.S. Geological Survey at 20 selected locations in the San Joaquin Valley. The recharge characteristics of a ground-water reservoir are indicated roughly by the volume ratio, which is subsidence/pumpage. In the Los Banos-Kettleman City area, the values of this ratio range from less than 0.2 near the perimeter to more than 0.6 in the central part of the area. In the corresponding parts of the Arvin-Maricopa area, the ratio ranges from near 0 to more than 0.4.

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Land Subsidence, Groundwater Levels, and Geology in the Coachella Valley, California, 1993–2010

U.S. Geological Survey (USGS) | June 6th, 2014

Summary

Land subsidence associated with groundwater-level declines has been investigated by the U.S. Geological Survey in the Coachella Valley, California, since 1996. Groundwate

Land subsidence associated with groundwater-level declines has been investigated by the U.S. Geological Survey in the Coachella Valley, California, since 1996. Groundwater has been a major source of agricultural, municipal, and domestic supply in the valley since the early 1920s. Pumping of groundwater resulted in water-level declines as much as 15 meters (50 feet) through the late 1940s. In 1949, the importation of Colorado River water to the southern Coachella Valley began, resulting in a reduction in groundwater pumping and a recovery of water levels during the 1950s through the 1970s. Since the late 1970s, demand for water in the valley has exceeded deliveries of imported surface water, resulting in increased pumping and associated groundwater-level declines and, consequently, an increase in the potential for land subsidence caused by aquifer-system compaction. Global Positioning System (GPS) surveying and Interferometric Synthetic Aperture Radar (InSAR) methods were used to determine the location, extent, and magnitude of the vertical land-surface changes in the southern Coachella Valley during 1993–2010. The GPS measurements taken at 11 geodetic monuments in 1996 and in 2010 in the southern Coachella Valley indicated that the elevation of the land surface changed –136 to –23 millimeters (mm) ±54 mm (–0.45 to –0.08 feet (ft) ±0.18 ft) during the 14-year period. Changes at 6 of the 11 monuments exceeded the maximum expected uncertainty of ±54 mm (±0.18 ft) at the 95-percent confidence level, indicating that subsidence occurred at these monuments between June 1996 and August 2010. GPS measurements taken at 17 geodetic monuments in 2005 and 2010 indicated that the elevation of the land surface changed –256 to +16 mm ±28 mm (–0.84 to +0.05 ft ±0.09 ft) during the 5-year period. Changes at 5 of the 17 monuments exceeded the maximum expected uncertainty of ±28 mm (±0.09 ft) at the 95-percent confidence level, indicating that subsidence occurred at these monuments between August 2005 and August 2010. At each of these five monuments, subsidence rates were about the same between 2005 and 2010 as between 2000 and 2005. InSAR measurements taken between June 27, 1995, and September 19, 2010, indicated that the land surface subsided from about 220 to 600 mm (0.72 to 1.97 ft) in three areas of the Coachella Valley: near Palm Desert, Indian Wells, and La Quinta. In Palm Desert, the average subsidence rates increased from about 39 millimeters per year (mm/yr), or 0.13 foot per year (ft/yr), during 1995–2000 to about 45 mm/yr (0.15 ft/yr) during 2003–10. In Indian Wells, average subsidence rates for two subsidence maxima were fairly steady at about 34 and 26 mm/yr (0.11 and 0.09 ft/yr) during both periods; for the third maxima, average subsidence rates increased from about 14 to 19 mm/yr (0.05 to 0.06 ft/yr) from the first to the second period. In La Quinta, average subsidence rates for five selected locations ranged from about 17 to 37 mm/yr (0.06 to 0.12 ft/yr) during 1995–2000; three of the locations had similar rates during 2003–mid-2009, while the other two locations had increased subsidence rates. Decreased subsidence rates were calculated throughout the La Quinta subsidence area during mid-2009–10, however, and uplift was observed during 2010 near the southern extent of this area. Water-level measurements taken at wells near the subsiding monuments and in the three subsiding areas shown by InSAR generally indicated that the water levels fluctuated seasonally and declined annually from the early 1990s, or earlier, to 2010; some water levels in 2010 were at the lowest levels in their recorded histories. An exception to annually declining water levels in and near subsiding areas was observed beginning in mid-2009 in the La Quinta subsidence area, where recovering water levels coincided with increased recharge operations at the Thomas E. Levy Recharge Facility; decreased pumpage also could cause groundwater levels to recover. Subsidence concomitant with declining water levels and land-surface uplift concomitant with recovering water levels indicate that aquifer-system compaction could be causing subsidence. If the stresses imposed by the historically lowest water levels exceeded the preconsolidation stress, the aquifer-system compaction and associated land subsidence could be permanent.

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Page : 1

Age Determination of the Remaining Peat in the Sacramento–San Joaquin Delta, California, USA

Analysis and simulation of regional subsidence accompanying groundwater abstraction and compaction of susceptible aquifer systems in the USA

Detection and Measurement of Land Subsidence Using Global Positioning System Surveying and Interferometric Synthetic Aperture Radar, Coachella Valley, California, 1996–2005

Detection of aquifer system compaction and land subsidence using interferometric synthetic aperture radar, Antelope Valley, Mojave Desert, California

Estimating the permanent loss of groundwater storage in the southern San Joaquin Valley, California

Factors and Processes Affecting Delta Levee System Vulnerability

Ground Water in the Central Valley, California - A Summary Report

Hydro-economic analysis of groundwater pumping for irrigated agriculture in California’s Central Valley, USA

Land subsidence in the San Joaquin Valley, California, as of 1972

Land Subsidence, Groundwater Levels, and Geology in the Coachella Valley, California, 1993–2010

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