Tracy Nishikawa
Tracy Nishikawa is a Scientist Emeritus at the California Water Science Center.
Science and Products
Filter Total Items: 38
Decoupled application of the integrated hydrologic model, GSFLOW, to estimate agricultural irrigation in the Santa Rosa Plain, California
No abstract available.
Authors
Joseph A. Hevesi, Linda R. Woolfenden, Richard G. Niswonger, R. Steven Regan, Tracy Nishikawa
A framework for sea level rise vulnerability assessment for southwest U.S. military installations
We describe an analysis framework to determine military installation vulnerabilities under increases in local mean sea level as projected over the next century. The effort is in response to an increasing recognition of potential climate change ramifications for national security and recommendations that DoD conduct assessments of the impact on U.S. military installations of climate change. Results
Authors
B. Chadwick, Reinhard Flick, J. Helly, Tracy Nishikawa, Fang Wang Pei, W. O'Reilly, R. Guza, Peter Bromirski, A. Young, W. Crampton, B. Wild, I. Canner
Optimal pump and recharge management model for nitrate removal in the Warren groundwater basin, California
The town of Yucca Valley located in the southwest part of the Mojave Desert in southern California relies on groundwater pumping from the Warren groundwater basin as its sole source of water supply. This significant dependency has resulted in a large imbalance between groundwater pumpage and natural recharge, causing groundwater levels in the basin to decline more than 90 m from the late 1940s to
Authors
Yung-Chia Chiu, Tracy Nishikawa, William W.‐G. Yeh
Arsenic management through well modification and simulation
Arsenic concentrations can be managed with a relatively simple strategy of grouting instead of completely destroying a selected interval of well. The strategy of selective grouting was investigated in Antelope Valley, California, where groundwater supplies most of the water demand. Naturally occurring arsenic typically exceeds concentrations of 10 (mu or u)g/L in the water produced from these long
Authors
Keith J. Halford, Christina L. Stamos, Tracy Nishikawa, Peter Martin
Development of an objective‐oriented groundwater model for conjunctive‐use planning of surface water and groundwater
In this paper we construct an objective‐oriented model for conjunctive‐use planning of surface water and groundwater for the Warren groundwater basin in southern California. The goal of conjunctive‐use planning is to decrease high‐nitrate concentration while maintaining groundwater levels at desired elevations and meeting water demand. We formulate a management problem that minimizes the total cos
Authors
Yung-Chia Chiu, Ne-Zheng Sun, Tracy Nishikawa, William W.‐G. Yeh
Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA
Groundwater pumping has led to extensive water-level declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was developed to test the hydraulic implications of a sequence-stratigraphic model of the Dominguez Gap area and to assess the effects of water-management scenarios. The model is two-dimensional, vertical and follows an approximate flow
Authors
Tracy Nishikawa, Adam J. Siade, Eric G. Reichard, Daniel J. Ponti, A.G. Canales, T.A. Johnson
Geohydrological characterization, water-chemistry, and ground-water flow simulation model of the Sonoma Valley area, Sonoma County, California
The Sonoma Valley, located about 30 miles north of San Francisco, is one of several basins in Sonoma County that use a combination of ground water and water delivered from the Russian River for supply. Over the past 30 years, Sonoma Valley has experienced rapid population growth and land-use changes. In particular, there has been a significant increase in irrigated agriculture, predominantly viney
Authors
Christopher D. Farrar, Loren F. Metzger, Tracy Nishikawa, Kathryn M. Koczot, Eric G. Reichard, Victoria E. Langenheim
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 1961, the San
Authors
Diane L. Rewis, Allen H. Christensen, Jonathan Matti, Joseph A. Hevesi, Tracy Nishikawa, Peter Martin
Water Resources Investigations at Edwards Air Force Base since 1988
Edwards Air Force Base (EAFB) in southern California (fig. 1) has relied on ground water to meet its water-supply needs. The extraction of ground water has led to two major problems that can directly affect the mission of EAFB: declining water levels (more than 120 ft since the 1920s) and land subsidence, a gradual downward movement of the land surface (more than 4 ft since the late 1920s). As wat
Authors
Michelle Sneed, Tracy Nishikawa, Peter Martin
Evaluation of geohydrologic framework, recharge estimates and ground-water flow of the Joshua Tree area, San Bernardino County, California
Ground water historically has been the sole source of water supply for the community of Joshua Tree in the Joshua Tree ground-water subbasin of the Morongo ground-water basin in the southern Mojave Desert. The Joshua Basin Water District (JBWD) supplies water to the community from the underlying Joshua Tree ground-water subbasin. The JBWD is concerned with the long-term sustainability of the under
Authors
Tracy Nishikawa, John A. Izbicki, Joseph A. Hevesi, Christina L. Stamos, Peter Martin
Comparison of ground-water flow model particle-tracking results and isotopic data in the Mojave River ground-water basin, southern California, USA
Flow-path and time-of-travel results for the Mojave River ground-water basin, southern California, calculated using the ground-water flow model MODFLOW and particle-tracking model MODPATH were similar to flow path and time-of-travel interpretations derived from delta-deuterium and carbon-14 data. Model and isotopic data both show short flow paths and young ground-water ages throughout the floodpla
Authors
John A. Izbicki, Christina L. Stamos, Tracy Nishikawa, Peter Martin
Geohydrology, Geochemistry, and Ground-Water Simulation-Optimization of the Central and West Coast Basins, Los Angeles County, California
Historical ground-water development of the Central and West Coast Basins in Los Angeles County, California through the first half of the 20th century caused large water-level declines and induced seawater intrusion. Because of this, the basins were adjudicated and numerous ground-water management activities were implemented, including increased water spreading, construction of injection barriers,
Authors
Eric G. Reichard, Michael Land, Steven M. Crawford, Tyler D. Johnson, Rhett R. Everett, Trayle V. Kulshan, Daniel J. Ponti, Keith L. Halford, Theodore A. Johnson, Katherine S. Paybins, Tracy Nishikawa
Science and Products
Filter Total Items: 38
Decoupled application of the integrated hydrologic model, GSFLOW, to estimate agricultural irrigation in the Santa Rosa Plain, California
No abstract available.
Authors
Joseph A. Hevesi, Linda R. Woolfenden, Richard G. Niswonger, R. Steven Regan, Tracy Nishikawa
A framework for sea level rise vulnerability assessment for southwest U.S. military installations
We describe an analysis framework to determine military installation vulnerabilities under increases in local mean sea level as projected over the next century. The effort is in response to an increasing recognition of potential climate change ramifications for national security and recommendations that DoD conduct assessments of the impact on U.S. military installations of climate change. Results
Authors
B. Chadwick, Reinhard Flick, J. Helly, Tracy Nishikawa, Fang Wang Pei, W. O'Reilly, R. Guza, Peter Bromirski, A. Young, W. Crampton, B. Wild, I. Canner
Optimal pump and recharge management model for nitrate removal in the Warren groundwater basin, California
The town of Yucca Valley located in the southwest part of the Mojave Desert in southern California relies on groundwater pumping from the Warren groundwater basin as its sole source of water supply. This significant dependency has resulted in a large imbalance between groundwater pumpage and natural recharge, causing groundwater levels in the basin to decline more than 90 m from the late 1940s to
Authors
Yung-Chia Chiu, Tracy Nishikawa, William W.‐G. Yeh
Arsenic management through well modification and simulation
Arsenic concentrations can be managed with a relatively simple strategy of grouting instead of completely destroying a selected interval of well. The strategy of selective grouting was investigated in Antelope Valley, California, where groundwater supplies most of the water demand. Naturally occurring arsenic typically exceeds concentrations of 10 (mu or u)g/L in the water produced from these long
Authors
Keith J. Halford, Christina L. Stamos, Tracy Nishikawa, Peter Martin
Development of an objective‐oriented groundwater model for conjunctive‐use planning of surface water and groundwater
In this paper we construct an objective‐oriented model for conjunctive‐use planning of surface water and groundwater for the Warren groundwater basin in southern California. The goal of conjunctive‐use planning is to decrease high‐nitrate concentration while maintaining groundwater levels at desired elevations and meeting water demand. We formulate a management problem that minimizes the total cos
Authors
Yung-Chia Chiu, Ne-Zheng Sun, Tracy Nishikawa, William W.‐G. Yeh
Stratigraphic controls on seawater intrusion and implications for groundwater management, Dominguez Gap area of Los Angeles, California, USA
Groundwater pumping has led to extensive water-level declines and seawater intrusion in coastal Los Angeles, California (USA). A SUTRA-based solute-transport model was developed to test the hydraulic implications of a sequence-stratigraphic model of the Dominguez Gap area and to assess the effects of water-management scenarios. The model is two-dimensional, vertical and follows an approximate flow
Authors
Tracy Nishikawa, Adam J. Siade, Eric G. Reichard, Daniel J. Ponti, A.G. Canales, T.A. Johnson
Geohydrological characterization, water-chemistry, and ground-water flow simulation model of the Sonoma Valley area, Sonoma County, California
The Sonoma Valley, located about 30 miles north of San Francisco, is one of several basins in Sonoma County that use a combination of ground water and water delivered from the Russian River for supply. Over the past 30 years, Sonoma Valley has experienced rapid population growth and land-use changes. In particular, there has been a significant increase in irrigated agriculture, predominantly viney
Authors
Christopher D. Farrar, Loren F. Metzger, Tracy Nishikawa, Kathryn M. Koczot, Eric G. Reichard, Victoria E. Langenheim
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 1961, the San
Authors
Diane L. Rewis, Allen H. Christensen, Jonathan Matti, Joseph A. Hevesi, Tracy Nishikawa, Peter Martin
Water Resources Investigations at Edwards Air Force Base since 1988
Edwards Air Force Base (EAFB) in southern California (fig. 1) has relied on ground water to meet its water-supply needs. The extraction of ground water has led to two major problems that can directly affect the mission of EAFB: declining water levels (more than 120 ft since the 1920s) and land subsidence, a gradual downward movement of the land surface (more than 4 ft since the late 1920s). As wat
Authors
Michelle Sneed, Tracy Nishikawa, Peter Martin
Evaluation of geohydrologic framework, recharge estimates and ground-water flow of the Joshua Tree area, San Bernardino County, California
Ground water historically has been the sole source of water supply for the community of Joshua Tree in the Joshua Tree ground-water subbasin of the Morongo ground-water basin in the southern Mojave Desert. The Joshua Basin Water District (JBWD) supplies water to the community from the underlying Joshua Tree ground-water subbasin. The JBWD is concerned with the long-term sustainability of the under
Authors
Tracy Nishikawa, John A. Izbicki, Joseph A. Hevesi, Christina L. Stamos, Peter Martin
Comparison of ground-water flow model particle-tracking results and isotopic data in the Mojave River ground-water basin, southern California, USA
Flow-path and time-of-travel results for the Mojave River ground-water basin, southern California, calculated using the ground-water flow model MODFLOW and particle-tracking model MODPATH were similar to flow path and time-of-travel interpretations derived from delta-deuterium and carbon-14 data. Model and isotopic data both show short flow paths and young ground-water ages throughout the floodpla
Authors
John A. Izbicki, Christina L. Stamos, Tracy Nishikawa, Peter Martin
Geohydrology, Geochemistry, and Ground-Water Simulation-Optimization of the Central and West Coast Basins, Los Angeles County, California
Historical ground-water development of the Central and West Coast Basins in Los Angeles County, California through the first half of the 20th century caused large water-level declines and induced seawater intrusion. Because of this, the basins were adjudicated and numerous ground-water management activities were implemented, including increased water spreading, construction of injection barriers,
Authors
Eric G. Reichard, Michael Land, Steven M. Crawford, Tyler D. Johnson, Rhett R. Everett, Trayle V. Kulshan, Daniel J. Ponti, Keith L. Halford, Theodore A. Johnson, Katherine S. Paybins, Tracy Nishikawa