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Allen Christensen (Former Employee)

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Mount San Jacinto after some winter storms and the windmills

Evaluating the Geohydrology in the San Gorgonio Pass Area

The San Gorgonio Pass, in southern California, is located between the San Bernardino and San Jacinto Mountain ranges. The mountain ranges to either side of the pass rise almost 9,000 feet (2,700 meters) above. The San Gorgonio Pass serves as a corridor for U.S. Interstate 10. It is also known for its strong winds that make it a popular spot for wind turbine energy production.
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California Water Science Center
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Evaluating the Geohydrology in the San Gorgonio Pass Area

The San Gorgonio Pass, in southern California, is located between the San Bernardino and San Jacinto Mountain ranges. The mountain ranges to either side of the pass rise almost 9,000 feet (2,700 meters) above. The San Gorgonio Pass serves as a corridor for U.S. Interstate 10. It is also known for its strong winds that make it a popular spot for wind turbine energy production.
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Alluvial aquifer sampling in Arizona

Southwest Gravity Program

The Southwest Gravity Program provides high-precision time-lapse gravity (repeat microgravity) data for hydrologic studies in the southwestern US. Recent projects include monitoring recharge underneath ephemeral-stream channels, monitoring aquifer-storage change in unconfined and compressible aquifers, measuring storage change at surface-spreading and injection-well artificial-recharge facilities...
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Arizona Water Science Center
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Southwest Gravity Program

The Southwest Gravity Program provides high-precision time-lapse gravity (repeat microgravity) data for hydrologic studies in the southwestern US. Recent projects include monitoring recharge underneath ephemeral-stream channels, monitoring aquifer-storage change in unconfined and compressible aquifers, measuring storage change at surface-spreading and injection-well artificial-recharge facilities...
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scrublands with hills in the background

Evaluation of groundwater resources of the Anza-Terwilliger area, Anza, California

Groundwater is the sole source for water use to the rural community and two Native American tribes in the Cahuilla Valley and Terwilliger Valley groundwater basins, which are located approximately 35 miles southwest of Palm Springs, California. The characteristics and sustainable yield of the basins are not well understood and are threatened by increasing water use and potential changes in water...
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California Water Science Center
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Evaluation of groundwater resources of the Anza-Terwilliger area, Anza, California

Groundwater is the sole source for water use to the rural community and two Native American tribes in the Cahuilla Valley and Terwilliger Valley groundwater basins, which are located approximately 35 miles southwest of Palm Springs, California. The characteristics and sustainable yield of the basins are not well understood and are threatened by increasing water use and potential changes in water...
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Gorgonio

San Gorgonio Pass Artificial Recharge Investigation

San Gorgonio Pass Water Agency (SGPWA) covers an area of 220 square miles in the mountain pass between the Upper Santa Ana River Basin to the west and the Coachella Valley to the east. Since 1961, when the SGPWA was formed, demand for ground water has increased with the increase in population within the agency boundaries. To prepare for future demands for water, the SGPWA has proposed to...
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California Water Science Center
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San Gorgonio Pass Artificial Recharge Investigation

San Gorgonio Pass Water Agency (SGPWA) covers an area of 220 square miles in the mountain pass between the Upper Santa Ana River Basin to the west and the Coachella Valley to the east. Since 1961, when the SGPWA was formed, demand for ground water has increased with the increase in population within the agency boundaries. To prepare for future demands for water, the SGPWA has proposed to...
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MODFLOW-2000 models used for groundwater simulation and management models for the Upper Klamath Basin, Oregon and California

This data release contains a three-dimensional groundwater flow model with example applications using MODFLOW-2000. The calibrated model is able to simulate observed decadal-scale climate-driven fluctuations in the groundwater system as well as observed shorter-term pumping-related fluctuations. Example model simulations show that the timing and location of the effects of groundwater...
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California Water Science Center

Select borehole data for Anza basin, Anza, CA

Borehole log number, State Well Number, location, construction information, and any wells tests performed on select wells from the Anza basin, Anza, CA. Also includes a lithologic data for a sub-set of borehole logs identified based on best coverage and representation of data within the study area.
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California Water Science Center

Electrical Resistivity Tomography in the Anza-Terwilliger Valley, Riverside County, California 2018

The Cahuilla Valley and Terwilliger Valley groundwater basins, 9-006 and 7-026 respectively (California Department of Water Resources 2016) located approximately 25 miles southwest of Palm Springs, are the sole-source for groundwater supply for the rural disadvantaged community and two Native American Tribes, the Ramona Band of Cahuilla and the Cahuilla,. The characteristics and...
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California Water Science Center
a green Anza Valley with mountains in the background
Anza Valley, CA
Anza Valley, CA
a green Anza Valley with mountains in the background

Anza Valley, CA

Anza Valley, CA

Groundwater is the sole source for water use to the rural community and two Native American tribes in the Cahuilla Valley and Terwilliger Valley groundwater basins, which are located approximately 35 miles southwest of Palm Springs, California.

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California Water Science Center
a green Anza Valley with mountains in the background

Anza Valley, CA

Anza Valley, CA

Groundwater is the sole source for water use to the rural community and two Native American tribes in the Cahuilla Valley and Terwilliger Valley groundwater basins, which are located approximately 35 miles southwest of Palm Springs, California.

By
California Water Science Center
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A basin-scale approach to estimating recharge in the desert: Anza-Cahuilla groundwater basin, CA

The Anza-Cahuilla groundwater basin located mainly in the semi-arid headwaters of the Santa Margarita River watershed in southern California is the principle source of groundwater for a rural disadvantaged community and two Native American Tribes, the Ramona Band of Cahuilla and the Cahuilla. Groundwater in the study area is derived entirely from precipitation and managing groundwater...
Authors
Michelle A. Stern, Lorraine E. Flint, Alan L. Flint, Allen H. Christensen
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Water Resources Mission Area, California Water Science Center

Depth to bedrock based on modeling of gravity data of the eastern part of Edwards Air Force Base, California

We describe a gravity survey acquired to determine the thickness of basin-fill deposits (depth to bedrock) and to delineate geologic structures that might influence groundwater flow beneath the eastern part of Edwards Air Force Base, California. Inversion of these gravity data combined with geologic map and well information provides an estimate of the thickness of basin-fill deposits...
Authors
Victoria E. Langenheim, Andrew Y. Morita, Allen H. Christensen, Geoffrey Cromwell, Christopher Palumbo Ely
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National Cooperative Geologic Mapping Program, Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center

Preliminary hydrogeologic assessment near the boundary of the Antelope Valley and El Mirage Valley groundwater basins, California

The increasing demands on groundwater for water supply in desert areas in California and the western United States have resulted in the need to better understand groundwater sources, availability, and sustainability. This is true for a 650-square-mile area that encompasses the Antelope Valley, El Mirage Valley, and Upper Mojave River Valley groundwater basins, about 50 miles northeast of...
Authors
Christina Stamos-Pfeiffer, Allen H. Christensen, Victoria E. Langenheim
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Water Resources Mission Area, California Water Science Center

Estimating natural recharge in San Gorgonio Pass watersheds, California, 1913–2012

A daily precipitation-runoff model was developed to estimate spatially and temporally distributed recharge for groundwater basins in the San Gorgonio Pass area, southern California. The recharge estimates are needed to define transient boundary conditions for a groundwater-flow model being developed to evaluate the effects of pumping and climate on the long-term availability of...
Authors
Joseph A. Hevesi, Allen H. Christensen
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Water Resources Mission Area, California Water Science Center

Aquifer geometry, lithology, and water levels in the Anza–Terwilliger area—2013, Riverside and San Diego Counties, California

The population of the Anza–Terwilliger area relies solely on groundwater pumped from the alluvial deposits and surrounding bedrock formations for water supply. The size, characteristics, and current conditions of the aquifer system in the Anza–Terwilliger area are poorly understood, however. In response to these concerns, the U.S. Geological Survey, in cooperation with the High Country...
Authors
Matthew K. Landon, Andrew Y. Morita, Joseph Nawikas, Allen H. Christensen, Dianna M. Crilley, Victoria E. Langenheim
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Water Resources Mission Area, California Water Science Center

Feasibility and potential effects of the proposed Amargosa Creek Recharge Project, Palmdale, California

Historically, the city of Palmdale and vicinity have relied on groundwater as the primary source of water, owing, in large part, to the scarcity of surface water in the region. Despite recent importing of surface water, groundwater withdrawal for municipal, industrial, and agricultural use has resulted in groundwater-level declines near the city of Palmdale in excess of 200 feet since...
Authors
Allen H. Christensen, Adam J. Siade, Peter Martin, Victoria E. Langenheim, Rufus D. Catchings, Matthew Alexander Burgess
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Water Resources Mission Area, California Water Science Center

Modeling a thick unsaturated zone at San Gorgonio Pass, California: lessons learned after five years of artificial recharge

The information flow among the tasks of framework assessment, numerical modeling, model forecasting and hind casting, and system-performance monitoring is illustrated. Results provide an understanding of artificial recharge in high-altitude desert settings where large vertical distances may separate application ponds from their target aquifers.Approximately 3.8 million cubic meters of...
Authors
Alan L. Flint, Kevin M. Ellett, Allen H. Christensen, Peter Martin
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Water Resources Mission Area, California Water Science Center

Geohydrology of Big Bear Valley, California: phase 1--geologic framework, recharge, and preliminary assessment of the source and age of groundwater

The Big Bear Valley, located in the San Bernardino Mountains of southern California, has increased in population in recent years. Most of the water supply for the area is pumped from the alluvial deposits that form the Big Bear Valley groundwater basin. This study was conducted to better understand the thickness and structure of the groundwater basin in order to estimate the quantity and...
Authors
Lorraine E. Flint, Justin T. Brandt, Allen H. Christensen, Alan L. Flint, Joseph A. Hevesi, Robert C. Jachens, Justin T. Kulongoski, Peter Martin, Michelle Sneed
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Water Resources Mission Area, California Water Science Center

The source, discharge, and chemical characteristics of water from Agua Caliente Spring, Palm Springs, California

Agua Caliente Spring, in downtown Palm Springs, California, has been used for recreation and medicinal therapy for hundreds of years and currently (2008) is the source of hot water for the Spa Resort owned by the Agua Caliente Band of the Cahuilla Indians. The Agua Caliente Spring is located about 1,500 feet east of the eastern front of the San Jacinto Mountains on the southeast-sloping...
Authors
Justin T. Brandt, Rufus D. Catchings, Allen H. Christensen, Alan L. Flint, Gini Gandhok, Mark Goldman, Keith J. Halford, Victoria E. Langenheim, Peter Martin, Michael Rymer, Roy A. Schroeder, Gregory J. Smith, Michelle Sneed
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Water Resources Mission Area, California Water Science Center

Aquifer Storage Recovery (ASR) of chlorinated municipal drinking water in a confined aquifer

About 1.02 × 106 m3 of chlorinated municipal drinking water was injected into a confined aquifer, 94–137 m below Roseville, California, between December 2005 and April 2006. The water was stored in the aquifer for 438 days, and 2.64 × 106 m3 of water were extracted between July 2007 and February 2008. On the basis of Cl− data, 35% of the injected water was recovered and 65% of the...
Authors
John A. Izbicki, Christen E. Petersen, Kenneth J. Glotzbach, Loren F. Metzger, Allen H. Christensen, Gregory J. Smith, David O'Leary, Miranda Fram, Trevor Joseph, Heather Shannon
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Water Resources Mission Area, California Water Science Center

Geology, ground-water hydrology, geochemistry, and ground-water simulation of the Beaumont and Banning Storage Units, San Gorgonio Pass area, Riverside County, California

Ground water has been the only source of potable water supply for residential, industrial, and agricultural users in the Beaumont and Banning storage units of the San Gorgonio Pass area, Riverside County, California. Ground-water levels in the Beaumont area have declined as much as 100 feet between the early 1920s and early 2000s, and numerous natural springs have stopped flowing. In...
Authors
Diane L. Rewis, Allen H. Christensen, Jonathan C. Matti, Joseph A. Hevesi, Tracy Nishikawa, Peter Martin
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Water Resources Mission Area, California Water Science Center

Generalized water-level contours, September-October 2000 and March-April 2001, and long-term water-level changes, at the U.S. Air Force Plant 42 and vicinity, Palmdale, California

Historically, the U.S. Air Force Plant 42 has relied on ground water as the primary source of water owing, in large part, to the scarcity of surface water in the region. Groundwater withdrawal for municipal, industrial, and agricultural use has affected ground-water levels at U.S. Air Force Plant 42, and vicinity. A study to document changes in groundwater gradients and to present...
Authors
Allen H. Christensen
Scientists from Kazakhstan Visit the California Water Science Center

Scientists from Kazakhstan Visit the California Water Science Center

Scientists from visited the Califonia Water Science Center to discuss California water issues as part of their national tour.

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