Gregory Mendez (Former Employee)
Science and Products
Filter Total Items: 22
An assessment of optical properties of dissolved organic material as quantitative source indicators in the Santa Ana River basin, Southern California
The ability to rapidly, reliably, and inexpensively characterize sources of dissolved organic material (DOM) in watersheds would allow water management agencies to more quickly identify problems in water sources, and to more efficiently allocate water resources by, for example, permitting real-time identification of high-quality water suitable for ground-water recharge, or poor-quality water in ne
Authors
Brian A. Bergamaschi, Erica Kalve, Larry Guenther, Gregory O. Mendez, Kenneth Belitz
Evaluation of two low-flow releases from Big Tujunga Reservoir, Los Angeles County, California, 2003
Since 1973, the Santa Ana Sucker (Catostomus santaanae) has been listed as a threatened species under the Endangered Species Act. The Lower Big Tujunga Creek, in Los Angeles County, is one of the areas in southern California where the Santa Ana Sucker is still present. This study was designed to assess two flow releases from Big Tujunga Dam that may contribute to favorable habitat conditions for t
Authors
Gregory O. Mendez
Assessing the Risk of Loveland Dam Operations to the Arroyo Toad (Bufo californicus) in the Sweetwater River Channel, San Diego County, California
No abstract available at this time
Authors
M. C. Madden-Smith, A.J. Atkinson, Robert N. Fisher, W.R. Danskin, Gregory O. Mendez
Geologic Setting, Geohydrology, and Ground-Water Quality near the Helendale Fault in the Mojave River Basin, San Bernardino County, California
The proximity of the Mojave River ground-water basin to the highly urbanized Los Angeles region has resulted in rapid population growth and, consequently, an increase in the demand for water. The Mojave River, the primary source of surface water for the region, normally is dry--except for periods of flow after intense storms; therefore, the region relies almost entirely on ground water to meet its
Authors
Christina L. Stamos, Brett F. Cox, John A. Izbicki, Gregory O. Mendez
Evaluation of tracer tests completed in 1999 and 2000 on the upper Santa Clara River, Los Angeles and Ventura Counties, California
The interaction of surface water and hyporheic water along the Santa Clara River in Los Angeles and Ventura Counties, California, was evaluated by conducting tracer tests and analyzing water-quality data under different flow conditions in October 1999 and May 2000. Tracer and water-quality samples were collected at multiple river and hyporheic sites as well as at the Los Angeles County Sanitation
Authors
Marisa H. Cox, Gregory O. Mendez, Charles R. Kratzer, Eric G. Reichard
Water quality monitoring of Sweetwater and Loveland reservoirs--Phase one results 1998-1999
In 1998, the U.S. Geological Survey began a study to assess the overall health of the watershed feeding the Sweetwater Reservoir in southern San Diego County, California. The study focussed on monitoring for organic chemical contamination and the effects of construction and operation of State Route 125 on water quality. Three environmental compartments (air, water, and bed sediments) are being sam
Authors
Michael S. Majewski, Jagdeep S. Sidhu, Gregory O. Mendez
Surface-water and ground-water quality in the Yucaipa area, San Bernardino and Riverside Counties, California, 1996-98
The quality of surface water and ground water in the Yucaipa area was evaluated to determine general chemical characteristics and to identify areas of recent ground-water recharge. Water samples, collected from 8 sites on 3 creeks and from 25 wells, were analyzed for general chemistry, nutrients, tritium, and stable isotopes of hydrogen and oxygen. At one production well (1S/2W-25R4), water sample
Authors
Gregory O. Mendez, Wesley R. Danskin, Carmen A. Burton
Stormflow chemistry in the Santa Ana River below Prado Dam and at the diversion downstream from Imperial Highway, southern California, 1995-98
The Santa Ana River drains about 2,670 square miles of the densely populated coastal area of southern California, near Los Angeles. Almost all the flow in the river, more than 200,000 acre-feet annually, is diverted into ponds where it infiltrates and recharges underlying aquifers. About 2 million people are dependent on these aquifers for water supply. Stormflow in the Santa Ana River is consider
Authors
John A. Izbicki, Gregory O. Mendez, Carmen A. Burton
Chemistry and isotopic composition of ground water along a section near the Newmark area, San Bernardino County, California
Chemical and isotopic analyses and flow-meter measurements in pumped wells were used to determine the source, movement, and age of ground water along a section of the valley-fill aquifer from the San Jacinto Fault to the base of the San Bernardino Mountains near the Newmark area in the Bunker Hill Basin of southern California. Water samples were collected from four multiple-depth well sites, from
Authors
John A. Izbicki, Wesley R. Danskin, Gregory O. Mendez
Regional water table (1996) and water-level changes in the Mojave River, the Morongo, and the Fort Irwin ground-water basins, San Bernardino County, California
The Mojave River, the Morongo, and the Fort Irwin ground-water basins lie in the southwestern part of the Mojave Desert Region of southern California. These basins supply ground water to local water districts, military bases, and private wells. The rapid growth in population in these basins, which is due, in part, to their proximity toLos Angeles, has increased the demand for water and, theref
Authors
Gregory O. Mendez, Allen H. Christensen
Science and Products
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Filter Total Items: 22
An assessment of optical properties of dissolved organic material as quantitative source indicators in the Santa Ana River basin, Southern California
The ability to rapidly, reliably, and inexpensively characterize sources of dissolved organic material (DOM) in watersheds would allow water management agencies to more quickly identify problems in water sources, and to more efficiently allocate water resources by, for example, permitting real-time identification of high-quality water suitable for ground-water recharge, or poor-quality water in neAuthorsBrian A. Bergamaschi, Erica Kalve, Larry Guenther, Gregory O. Mendez, Kenneth BelitzEvaluation of two low-flow releases from Big Tujunga Reservoir, Los Angeles County, California, 2003
Since 1973, the Santa Ana Sucker (Catostomus santaanae) has been listed as a threatened species under the Endangered Species Act. The Lower Big Tujunga Creek, in Los Angeles County, is one of the areas in southern California where the Santa Ana Sucker is still present. This study was designed to assess two flow releases from Big Tujunga Dam that may contribute to favorable habitat conditions for tAuthorsGregory O. MendezAssessing the Risk of Loveland Dam Operations to the Arroyo Toad (Bufo californicus) in the Sweetwater River Channel, San Diego County, California
No abstract available at this timeAuthorsM. C. Madden-Smith, A.J. Atkinson, Robert N. Fisher, W.R. Danskin, Gregory O. MendezGeologic Setting, Geohydrology, and Ground-Water Quality near the Helendale Fault in the Mojave River Basin, San Bernardino County, California
The proximity of the Mojave River ground-water basin to the highly urbanized Los Angeles region has resulted in rapid population growth and, consequently, an increase in the demand for water. The Mojave River, the primary source of surface water for the region, normally is dry--except for periods of flow after intense storms; therefore, the region relies almost entirely on ground water to meet itsAuthorsChristina L. Stamos, Brett F. Cox, John A. Izbicki, Gregory O. MendezEvaluation of tracer tests completed in 1999 and 2000 on the upper Santa Clara River, Los Angeles and Ventura Counties, California
The interaction of surface water and hyporheic water along the Santa Clara River in Los Angeles and Ventura Counties, California, was evaluated by conducting tracer tests and analyzing water-quality data under different flow conditions in October 1999 and May 2000. Tracer and water-quality samples were collected at multiple river and hyporheic sites as well as at the Los Angeles County SanitationAuthorsMarisa H. Cox, Gregory O. Mendez, Charles R. Kratzer, Eric G. ReichardWater quality monitoring of Sweetwater and Loveland reservoirs--Phase one results 1998-1999
In 1998, the U.S. Geological Survey began a study to assess the overall health of the watershed feeding the Sweetwater Reservoir in southern San Diego County, California. The study focussed on monitoring for organic chemical contamination and the effects of construction and operation of State Route 125 on water quality. Three environmental compartments (air, water, and bed sediments) are being samAuthorsMichael S. Majewski, Jagdeep S. Sidhu, Gregory O. MendezSurface-water and ground-water quality in the Yucaipa area, San Bernardino and Riverside Counties, California, 1996-98
The quality of surface water and ground water in the Yucaipa area was evaluated to determine general chemical characteristics and to identify areas of recent ground-water recharge. Water samples, collected from 8 sites on 3 creeks and from 25 wells, were analyzed for general chemistry, nutrients, tritium, and stable isotopes of hydrogen and oxygen. At one production well (1S/2W-25R4), water sampleAuthorsGregory O. Mendez, Wesley R. Danskin, Carmen A. BurtonStormflow chemistry in the Santa Ana River below Prado Dam and at the diversion downstream from Imperial Highway, southern California, 1995-98
The Santa Ana River drains about 2,670 square miles of the densely populated coastal area of southern California, near Los Angeles. Almost all the flow in the river, more than 200,000 acre-feet annually, is diverted into ponds where it infiltrates and recharges underlying aquifers. About 2 million people are dependent on these aquifers for water supply. Stormflow in the Santa Ana River is considerAuthorsJohn A. Izbicki, Gregory O. Mendez, Carmen A. BurtonChemistry and isotopic composition of ground water along a section near the Newmark area, San Bernardino County, California
Chemical and isotopic analyses and flow-meter measurements in pumped wells were used to determine the source, movement, and age of ground water along a section of the valley-fill aquifer from the San Jacinto Fault to the base of the San Bernardino Mountains near the Newmark area in the Bunker Hill Basin of southern California. Water samples were collected from four multiple-depth well sites, fromAuthorsJohn A. Izbicki, Wesley R. Danskin, Gregory O. MendezRegional water table (1996) and water-level changes in the Mojave River, the Morongo, and the Fort Irwin ground-water basins, San Bernardino County, California
The Mojave River, the Morongo, and the Fort Irwin ground-water basins lie in the southwestern part of the Mojave Desert Region of southern California. These basins supply ground water to local water districts, military bases, and private wells. The rapid growth in population in these basins, which is due, in part, to their proximity toLos Angeles, has increased the demand for water and, therefAuthorsGregory O. Mendez, Allen H. Christensen