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Sample records for imperial valley california

  1. Liquefaction sites, Imperial Valley, California.

    USGS Publications Warehouse

    Youd, T.L.; Bennett, M.J.

    1983-01-01

    Sands that did and did not liquefy at two sites during the 1979 Imperial Valley, Calif., earthquake (ML = 6.6) are identified and their properties evaluated. SPT tests were used to evaluate liquefaction susceptibility. Loose fine sands in an abandoned channel liquefied and produced sand boils, ground fissures, and a lateral spread at the Heber Road sites. Evidence of liquefaction was not observed over moderately dense over-bank sand east of the channel nor over dense point-bar sand to the west. -from ASCE Publications Information

  2. Surface Deformation in Imperial Valley, Southern California

    NASA Astrophysics Data System (ADS)

    Eneva, M.; Adams, D.; Falorni, G.; Morgan, J.

    2013-12-01

    The Imperial Valley in southern California is subjected to significant tectonic deformation resulting from the relative movement of the North American and Pacific plates. It is characterized by large earthquakes, frequent swarm activity, and aseismic events. High heat flow makes possible the operation of geothermal fields, some of which cause man-made surface displacements superimposed on the tectonic deformation. We apply radar interferometry (InSAR) to analyze Envisat ASAR data for the period 2003-2010. The SqueeSAR technique is used to obtain deformation time series and annual rates at numerous locations of permanent and distributed scatterers (PS and DS). SqueeSAR works very well in agricultural areas, where conventional differential InSAR (DinSAR) fails. We observe differential movements marking the Superstition Hills, San Andreas, and Imperial faults. The Imperial fault traverses agricultural fields, where DInSAR does not work and thus our SqueeSAR observations are the first for this fault (Fig. 1). We also observe steps in the deformation time series around the Superstition Hills fault from an October 2006 aseismic event and the April 2010 M7.2 earthquake south of the U.S.-Mexico border. Significant annual deformation rates are detected in the current geothermal fields. For example, subsidence of up to -50 mm/year is seen at the Salton Sea field (Fig. 2), and both subsidence and uplift are seen at Heber. We also determine the deformation baseline at prospective geothermal fields, thus making it possible in the future to distinguish between man-made and tectonic causes of surface deformation. Fig. 1. Line-of-sight (LOS) deformation indicates differential displacement on both sides of Imperial Fault. Movements away from the satellite are shown in yellow to red, and towards the satellite in blue. Larger deformation is associated with two geothermal fields, Heber (to the south-west) and East Mesa (to the east). Fig. 2. Subsidence in the Salton Sea geothermal

  3. Imperial Valley and Salton Sea, California

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Southern California's Salton Sea is a prominent visual for astronauts. This large lake supports the rich agricultural fields of the Imperial, Coachella and Mexicali Valleys in the California and Mexico desert. The Salton Sea formed by accident in 1905 when an irrigation canal ruptured, allowing the Colorado River to flood the Salton Basin. Today the Sea performs an important function as the sink for agricultural runoff; water levels are maintained by the runoff from the surrounding agricultural valleys. The Salton Sea salinity is high-nearly 1/4 saltier than ocean water-but it remains an important stopover point for migratory water birds, including several endangered species. The region also experiences several environmental problems. The recent increased demands for the limited Colorado River water threatens the amount of water allowed to flow into the Salton Sea. Increased salinity and decreased water levels could trigger several regional environmental crises. The agricultural flow into the Sea includes nutrients and agricultural by-products, increasing the productivity and likelihood of algae blooms. This image shows either a bloom, or suspended sediment (usually highly organic) in the water that has been stirred up by winds. Additional information: The Salton Sea A Brief Description of Its Current Conditions, and Potential Remediation Projects and Land Use Across the U.S.-Mexico Border Astronaut photograph STS111-E-5224 was taken by the STS-111 Space Shuttle crew that recently returned from the International Space Station. The image was taken June 12, 2002 using a digital camera. The image was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  4. A seismic refraction survey of the Imperial Valley Region, California

    NASA Astrophysics Data System (ADS)

    Fuis, G. S.; Mooney, W. D.; Healy, J. H.; McMechan, G. A.; Lutter, W. J.

    1984-02-01

    The U.S. Geological Survey conducted an extensive seismic refraction survey in the Imperial Valley region of California in 1979. The Imperial Valley is located in the Salton Trough, an active rift between the Pacific and North American plates. Forty shots fired at seven shot points were recorded by 100 portable seismic instruments at typical spacing of 0.5-1 km. More than 1300 recording locations were occupied, and more than 3000 usable seismograms were obtained. We analyzed five profiles using a standard ray-tracing program, constructed a contour map of reduced travel times from our most widely recorded shot point, and modeled an existing gravity profile across the Salton Trough. Results are itemized: (1) All models have in common a sedimentary layer (Vp = 1.8-5.0 km/s), a "transition zone" (Vp = 5.0-5.65 km/s), a basement (Vp = 5.65 km/s in the Imperial Valley, 5.9 km/s on the bordering mesas), and subbasement (Vp = 7.2 km/s). (2) The sedimentary layer ranges in thickness along the axis of the Salton Trough from 3.7 km (Salton Sea) to 4.8 km (U.S.-Mexican border). On the bordering mesas it is quite variable in thickness. (3) The "transition" zone is about 1 km thick in most places. In the Imperial Valley there are no marked velocity discontinuities in this zone between the sedimentary layer and basement. On the bordering mesas, however, there is a discontinuity at the top of this zone. (4) There are apparently two types of basement. On the bordering mesas, basement is crystalline igneous and metamorphic rocks. In the Imperial Valley, basement is mostly lower-greenshist-facies sedimentary rocks, based primarily on the smooth transition in character from sediment to basement arrivals, the low value of basement velocity, and the fact that deep (4 km) wells in the valley penetrate only the upper part of the known Cenozoic stratigraphic column for the Salton Trough. (5) The subbasement, or intermediate crustal layer, ranges in depth along the axis of the Salton Trough

  5. Measuring ground movement in geothermal areas of Imperial Valley, California

    NASA Technical Reports Server (NTRS)

    Lofgren, B. E.

    1974-01-01

    Significant ground movement may accompany the extraction of large quantities of fluids from the subsurface. In Imperial Valley, California, one of the potential hazards of geothermal development is the threat of both subsidence and horizontal movement of the land surface. Regional and local survey nets are being monitored to detect and measure possible ground movement caused by future geothermal developments. Precise measurement of surface and subsurface changes will be required to differentiate man-induced changes from natural processes in this tectonically active region.

  6. Overview of Reclamation's geothermal program in Imperial Valley, California

    NASA Technical Reports Server (NTRS)

    Fulcher, M. K.

    1974-01-01

    The Bureau of Reclamation is presently involved in a unique Geothermal Resource Development Program in Imperial Valley, California. The main purpose of the investigations is to determine the feasibility of providing a source of fresh water through desalting geothermal fluids stored in the aquifers underlying the valley. Significant progress in this research and development stage to date includes extensive geophysical investigations and the drilling of five geothermal wells on the Mesa anomaly. Four of the wells are for production and monitoring the anomaly, and one will be used for reinjection of waste brines from the desalting units. Two desalting units, a multistage flash unit and a vertical tube evaporator unit, have been erected at the East Mesa test site. The units have been operated on shakedown and continuous runs and have produced substantial quantities of high-quality water.

  7. Seismic and geodetic studies of the Imperial Valley, California

    SciTech Connect

    Jackson, D.D.

    1981-05-01

    The Imperial Valley exhibits perhaps the most active current tectonism in the United States; patterns of gravitational and thermal anomalies, along with geodetic measurements, strike-slip faulting, and recent volcanism suggest that the continental crust may still be spreading (Elders et al., 1972). In recent years, the United States Geological Survey and Caltech have added new seismic stations into a dense network in the Imperial Valley to study in detail the relationship between geothermal areas and earthquakes, and to understand the tectonic processes taking place there. The purposes of this study are to: (1) examine crustal structure using recently available data on P-wave arrival times of local earthquakes; (2) examine the leveling data for evidence of tectonic subsidence or uplift; and (3) study correlations between seismicity, seismic velocity, geodetic motion, geothermal activity, and local geology to provide a more consistent picture of the tectonics of the Imperial Valley.

  8. Salton Sea and Imperial Valley, California as seen from the Apollo 7 spacecra

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Salton Sea and Imperial Valley area of southern California, including a portion of northern Baja California, Mexico, as seen from the Apollo 7 spacecraft during its 17th revolution of the earth. Photographed from an altitude of 125 nautical miles, at ground elapsed time of 27 hours.

  9. Crustal Structure in the Imperial Valley Region of California From Active-Source Seismic Investigations

    NASA Astrophysics Data System (ADS)

    Fuis, G. S.; Mooney, W. D.

    2008-12-01

    New crust is being generated by rifting in the Salton Trough. As the rift opens, mafic intrusive rocks fill it from below as young sedimentary rocks fill it from above. Rifting and intrusion produce high heat flow and temperatures that metamorphose the sedimentary rocks to shallow depths, forming a metasedimentary basement in the central part of the Trough, or Imperial Valley, thus consolidating the new crust. The U.S. Geological Survey conducted an extensive seismic-refraction survey in the Imperial Valley region of California in 1979, and recorded additional data in 1992. Profile data were modeled using a combination of forward and inverse modeling techniques. First arrivals on profiles and arrays from all shots were combined in an inversion for a basement-depth model. Finally an an existing gravity profile across the Salton Trough was modeled. Results are as follows: (1) No first-order velocity discontinuity is observed between sedimentary and "basement" rocks in the Imperial Valley; whereas such a discontinuity is observed on West Mesa, west of the Imperial Valley. In the Imperial Valley, basement velocity is 5.65 km/s, and basement is as much as 6 km deep. On West Mesa, basement velocity is 5.9 km/s and is at most 2 km deep. In the Imperial Valley, basement shoals beneath known geothermal areas, and the deepest wells (approx. 4 km) have penetrated only the upper part of the known Cenozoic stratigraphic column in the Salton Trough. Based on these results, we interpret basement in the Imperial Valley to be sedimentary rocks metamorphosed to lower greenschist facies and basement on West Mesa to be crystalline rocks. (2) The Imperial fault offsets basement in a normal sense by as much as 1 km down to the northeast, and there is an irregular basement scarp as high as 3.5 km between West Mesa and the Imperial Valley, which we interpret as a rift suture between old crystalline and young metasedimentary basement. (3) "Subbasement" (Vp 6.9 km/s) is seen at depths as

  10. Global Positioning System measurements of strain accumulation across the Imperial Valley, California - 1986-1989

    NASA Astrophysics Data System (ADS)

    Larsen, Shawn; Reilinger, Robert

    1992-06-01

    The Global Positioning System (GPS) data collected in southern California from 1986 to 1989 indicate considerable strain accumulation across the Imperial Valley. Displacements are computed at 29 stations in and near the valley from 1986 to 1988, and at 11 sites from 1988 to 1989. The earlier measurements indicate 5.9 =/- 1.0 cm/yr right-lateral differential velocity across the valley, although the data are heavily influenced by the 1987 Superstition Hills earthquake sequence. Some measurements, especially the east-trending displacements, are suspects for large errors. The 1988 to 1989 GPS displacements are best modeled by 5.2 =/- 0.9 cm/yr of valley crossing deformation, but rates calculated from conventional geodetic measurements (3.4 to 4.3 cm/yr) fit the data nearly as well. There is evidence from GPS and Very Long Base Interferometry (VLBI) observations that the present slip rate along the southern San Andreas fault is smaller than the long-term geologic estimate, suggesting a lower earthquake potential than is currently assumed. Correspondingly, a higher earthquake potential is indicated for the San Jacinto fault. The Imperial Valley GPS sites form part of a 183 station network in southern California and northern Baja California, which spans a cross-section of the North American-Pacific plate boundary.

  11. GPS measurements of strain accumulation across the Imperial Valley, California: 1986-1989

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert

    1989-01-01

    The Global Positioning System (GPS) data collected in southern California from 1986 to 1989 indicate considerable strain accumulation across the Imperial Valley. Displacements are computed at 29 stations in and near the valley from 1986 to 1988, and at 11 sites from 1988 to 1989. The earlier measurements indicate 5.9 +/- 1.0 cm/yr right-lateral differential velocity across the valley, although the data are heavily influenced by the 1987 Superstition Hills earthquake sequence. Some measurements, especially the east-trending displacements, are suspects for large errors. The 1988 to 1989 GPS displacements are best modeled by 5.2 +/- 0.9 cm/yr of valley crossing deformation, but rates calculated from conventional geodetic measurements (3.4 to 4.3 cm/yr) fit the data nearly as well. There is evidence from GPS and Very Long Base Interferometry (VLBI) observations that the present slip rate along the southern San Andreas fault is smaller than the long-term geologic estimate, suggesting a lower earthquake potential than is currently assumed. Correspondingly, a higher earthquake potential is indicated for the San Jacinto fault. The Imperial Valley GPS sites form part of a 183 station network in southern California and northern Baja California, which spans a cross-section of the North American-Pacific plate boundary.

  12. Global Positioning System measurements of strain accumulation across the Imperial Valley, California - 1986-1989

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert

    1992-01-01

    The Global Positioning System (GPS) data collected in southern California from 1986 to 1989 indicate considerable strain accumulation across the Imperial Valley. Displacements are computed at 29 stations in and near the valley from 1986 to 1988, and at 11 sites from 1988 to 1989. The earlier measurements indicate 5.9 =/- 1.0 cm/yr right-lateral differential velocity across the valley, although the data are heavily influenced by the 1987 Superstition Hills earthquake sequence. Some measurements, especially the east-trending displacements, are suspects for large errors. The 1988 to 1989 GPS displacements are best modeled by 5.2 =/- 0.9 cm/yr of valley crossing deformation, but rates calculated from conventional geodetic measurements (3.4 to 4.3 cm/yr) fit the data nearly as well. There is evidence from GPS and Very Long Base Interferometry (VLBI) observations that the present slip rate along the southern San Andreas fault is smaller than the long-term geologic estimate, suggesting a lower earthquake potential than is currently assumed. Correspondingly, a higher earthquake potential is indicated for the San Jacinto fault. The Imperial Valley GPS sites form part of a 183 station network in southern California and northern Baja California, which spans a cross-section of the North American-Pacific plate boundary.

  13. Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California

    NASA Astrophysics Data System (ADS)

    Lindsey, Eric O.; Fialko, Yuri

    2016-02-01

    We analyze a suite of geodetic observations across the Imperial Fault in southern California that span all parts of the earthquake cycle. Coseismic and postseismic surface slips due to the 1979 M 6.6 Imperial Valley earthquake were recorded with trilateration and alignment surveys by Harsh (1982) and Crook et al. (1982), and interseismic deformation is measured using a combination of multiple interferometric synthetic aperture radar (InSAR)-viewing geometries and continuous and survey-mode GPS. In particular, we combine more than 100 survey-mode GPS velocities with InSAR data from Envisat descending tracks 84 and 356 and ascending tracks 77 and 306 (149 total acquisitions), processed using a persistent scatterers method. The result is a dense map of interseismic velocities across the Imperial Fault and surrounding areas that allows us to evaluate the rate of interseismic loading and along-strike variations in surface creep. We compare available geodetic data to models of the earthquake cycle with rate- and state-dependent friction and find that a complete record of the earthquake cycle is required to constrain key fault properties including the rate-dependence parameter (a - b) as a function of depth, the extent of shallow creep, and the recurrence interval of large events. We find that the data are inconsistent with a high (>30 mm/yr) slip rate on the Imperial Fault and investigate the possibility that an extension of the San Jacinto-Superstition Hills Fault system through the town of El Centro may accommodate a significant portion of the slip previously attributed to the Imperial Fault. Models including this additional fault are in better agreement with the available observations, suggesting that the long-term slip rate of the Imperial Fault is lower than previously suggested and that there may be a significant unmapped hazard in the western Imperial Valley.

  14. Shallow velocity structure in the Imperial Valley region of Southern California

    NASA Astrophysics Data System (ADS)

    Ma, Y.; Stock, J. M.; Hole, J. A.; Fuis, G. S.

    2013-12-01

    The Imperial Valley, located south of the Salton Sea of Southern California, contains a pull-apart basin formed by the on-going oblique extension between the southernmost San Andreas fault and the northern Imperial fault. In this very seismically active area, the earthquakes tend to occur in the form of seismic swarms (e.g. events in August 2012), often related to the geothermal systems in the valley. Previous active seismic studies (e.g. Fuis et al. 1979, Parsons and McCarthy 1996) have revealed major crustal structures including the shallow basin structures in the valley and surroundings, based primarily on 2D models. A better 3D structure model is still awaiting construction to provide improved information on the location of earthquakes, faults, fault-zone properties, and the evolution of the basin. The 2011 Salton Seismic Imaging Project (SSIP) deployed a seismic array at 2-km grid spacing in the central northern part of the valley (Line 11), and three longer seismic lines across the valley with active sources (Lines 1, 2, and 3). Here we will present the shallow (to 8-km depth) 3D structure in this region obtained by modeling the traveltimes of the first arrivals in these recordings and from earlier experiments. We have processed arrivals from all shots at all receivers, from the SSIP dataset, in the region south of the Salton Sea. Relevant data from the 1979 Imperial Valley experiment has also been used. The 3D structure of the valley was inverted from the surface to 8-km depth using the technique of Hole (1992). On average, the velocity increases rapidly from ~2 km/s at the surface to 5.6 km/s at 5 km depth, a velocity range corresponding to the unmetamorphosed sediments (Fuis et al. 1984). Below 5-km depth, velocity increases slowly to 6.3 km/s at 8-km depth, a velocity range corresponding to the metasedimentary rocks, or 'basement' (Fuis et al. 1984). In depth slices, geothermal areas are characterized by high velocity zones. Specifically, we observe a

  15. Earthquakes, active faults, and geothermal areas in the Imperial Valley, California

    USGS Publications Warehouse

    Hill, D.P.; Mowinckel, P.; Peake, L.G.

    1975-01-01

    A dense seismograph network in the Imperial Valley recorded a series of earthquake swarms along the Imperial and Brawley faults and a diffuse pattern of earthquakes along the San Jacinto fault. Two known geothermal areas are closely associated with these earthquake swarms. This seismicity pattern demonstrates that seismic slip is occurring along both the Imperial-Brawley and San Jacinto fault systems.

  16. Earthquakes, active faults, and geothermal areas in the imperial valley, california.

    PubMed

    Hill, D P; Mowinckel, P; Peake, L G

    1975-06-27

    A dense seismograph network in the Imperial Valley recorded a series of earthquake swarms along the Imperial and Brawley faults and a diffuse pattern of earthquakes along the San Jacinto fault. Two known geothermal areas are closely associated with these earthquake swarms. This seismicity pattern demonstrates that seismic slip is occurring along both the Imperial-Brawley and San Jacinto fault systems. PMID:17772600

  17. Local variations of seismic velocity in the Imperial Valley, California

    SciTech Connect

    Jackson, D.D.; Lee, W.B.

    1981-12-01

    The authors inverted local earthquake arrival times to estimate spatial variations of seismic velocity. Their model consisted of near-surface station corrections and local perturbations to a standard crustal velocity model. The authors found a zone of relatively high-velocity trending southeast from the Salton Sea. This zone corresponds to the region of thickest sediments. The authors compared results with those of teleseismic studies by Savino et al (1977). The agreement was excellent, suggesting that the teleseismic delays are caused primarily by crustal velocity variations. Residual delays between the teleseismic observations and predicted crustal delays imply crustal thinning of 3 or 4 km along the axis of the valley. Known geothermal resource areas at Salton Sea (or Obsidian Buttes), Brawley, and East Mesa, lie on the axis of a zone of thin crust, and they may be intimately related to the Brawley fault. Neither local earthquake nor teleseismic arrival times can discriminate between these hypotheses, but the issue might be resolved by combining both types of data. Known geothermal resource areas at Heber, Dunes, and Glamis, lie away from the projected trace of the Brawley fault. These areas are nearly aseismic, and overlie crust with apparent seismic velocities only mildly higher than the regional average. These apparent velocity anomalies could be related to crustal thinning, but because of the very mild Bouguer gravity anomalies in these areas, it seems more likely that the velocity anomalies occur entirely within the crust. 7 references, 6 figures, 3 tables.

  18. Bioindicators from Mosquitofish (Gambusia affinis) Sampled from the Imperial Valley in Southern California

    USGS Publications Warehouse

    Jenkins, Jill A.; Draugelis-Dale, Rassa O.

    2006-01-01

    The Sonny Bono Salton Sea National Wildlife Refuge (SSNWR) is located 64 km north of the Mexican border at the southern end of the Salton Sea in California's Imperial Valley. Freshwater ponds and managed habitats at the SSNWR, Calipatria, Calif. are supplied with Colorado River water that carries compounds from upstream sources. Components include municipal and industrial discharges, agricultural drainage, and sewage plant inputs. Aquatic animals in these ecosystems are continuously exposed to multiple constituents, several of which have been demonstrated to be associated with hormonal disturbances. We investigated possible endocrine impacts to fish in the Imperial Valley, Calif., by addressing the null hypothesis that aquatic species in impacted sites did not exhibit evidence of endocrine disruption as compared with those from nonimpacted sites. The results presented are intended to provide managers with science-based information and interpretations about the condition of the animals in their ecosystems for the minimization of potential adverse effects to trust fish and wildlife resources and for the maximization of available water resources.

  19. Interpretation of shallow crustal structure of the Imperial Valley, California, from seismic reflection profiles

    SciTech Connect

    Severson, L.K.

    1987-05-01

    Eight seismic reflection profiles (285 km total length) from the Imperial Valley, California, were provided to CALCRUST for reprocessing and interpretation. Two profiles were located along the western margin of the valley, five profiles were situated along the eastern margin and one traversed the deepest portion of the basin. These data reveal that the central basin contains a wedge of highly faulted sediments that thins to the east. Most of the faulting is strike-slip but there is evidence for block rotations on the scale of 5 to 10 kilometers within the Brawley Seismic Zone. These lines provide insight into the nature of the east and west edges of the Imperial Valley. The basement at the northwestern margin of the valley, to the north of the Superstition Hills, has been normal-faulted and blocks of basement material have ''calved'' into the trough. A blanket of sediments has been deposited on this margin. To the south of the Superstition Hills and Superstition Mountain, the top of the basement is a detachment surface that dips gently into the basin. This margin is also covered by a thick sequence sediments. The basement of the eastern margin consists of metamorphic rocks of the upper plate of the Chocolate Mountain Thrust system underlain by the Orocopia Schist. These rocks dip to the southeast and extend westward to the Sand Hills Fault but do not appear to cross it. Thus, the Sand Hills Fault is interpreted to be the southern extension of the San Andreas Fault. North of the Sand Hills Fault the East Highline Canal seismicity lineament is associated with a strike-slip fault and is probably linked to the Sand Hills Fault. Six geothermal areas crossed by these lines, in agreement with previous studies of geothermal reservoirs, are associated with ''faded'' zones, Bouguer gravity and heat flow maxima, and with higher seismic velocities than surrounding terranes.

  20. Well log interpretation of certain geothermal fields in the Imperial Valley, California

    SciTech Connect

    Ershaghi, I.; Abdassah, D.

    1984-03-01

    This study reviews the wireline log responses of some geothermal fields in the Imperial Valley, California. The fields under study include the Heber, the East Mesa, the Brawley, and the Westmoreland. The well logs used in the study did not include all the wireline surveys obtained by the operators. The selected well logs obtained under special arrangements with the operators were chosen to maintain the anonymity of specific well locations but are only representative of each area. Analysis of the well logs indicates that on an individual field basis, the well logs are excellent for correlation purposes. The presence of extremely saline fluids in some fields precludes the monitoring of Q/sub v/ (cation exchange capacity per unit volume) profile for detection of hydrothermally altered zones. The producing sections in all the fields are characterized by low porosity and high resistivity.

  1. Reclaiming agricultural drainage water with nanofiltration membranes: Imperial Valley, California, USA

    USGS Publications Warehouse

    Kharaka, Y.K.; Schroeder, R.A.; Setmire, J.G.

    2003-01-01

    We conducted pilot-scale field experiments using nanofiltration membranes to lower the salinity and remove Se, As and other toxic contaminants from saline agricultural wastewater in the Imperial Valley, California, USA. Farmlands in the desert climate (rainfall - 7.4 cm/a) of Imperial Valley cover -200,000 ha that are irrigated with water (-1.7 km3 annually) imported from the Colorado River. The salinity (-850 mg/L) and concentration of Se (-2.5 ??g/L) in the Colorado River water are high and evapotranpiration further concentrates salts in irrigation drainage water, reaching salinities of 3,000-15,000 mg/L TDS and a median Se value of -30 ??g/L. Experiments were conducted with two commercially available nanofiltration membranes, using drainage water of varying composition, and with or without the addition of organic precipitation inhibitors. Results show that these membranes selectively remove more than 95% of Se, SO4, Mo, U and DOC, and -30% of As from this wastewater. Low percentages of Cl, NO3 and HCO3, with enough cations to maintain electrical neutrality also were removed. The product water treated by these membranes comprised more than 90% of the wastewater tested. Results indicate that the treated product water from the Alamo River likely will have less than 0.2 ??g/L Se, salinity of 300-500 mg/L TDS and other chemical concentrations that meet the water quality criteria for irrigation and potable use. Because acceptability is a major issue for providing treated wastewater to urban centers, it may be prudent to use the reclaimed water for irrigation and creation of lower salinity wetlands near the Salton Sea; an equivalent volume of Colorado River water can then be diverted for the use of increasing populations of San Diego and other urban centers in southern California. Nanofiltration membranes yield greater reclaimed-water output and require lower pressure and less pretreatment, and therefore are generally more cost effective than traditional reverse

  2. Age constraints for the present fault configuration in the Imperial Valley, California - Evidence for northwestward propagation of the Gulf of California rift system

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert

    1991-01-01

    Releveling and other geophysical data for the Imperial Valley of southern California suggest the northern section of the Imperial-Brawley fault system, which includes the Mesquite Basin and Brawley Seismic Zone, is much younger than the 4 to 5 million year age of the valley itself. A minimum age of 3000 years is calculated for the northern segment of the Imperial fault from correlations between surface topography and geodetically observed seismic/interseismic vertical movements. Calculations of a maximum age of 80,000 years is based upon displacements in the crystalline basement along the Imperial fault, inferred from seismic refraction surveys. This young age supports recent interpretations of heat flow measurements, which also suggest that the current patterns of seismicity and faults in the Imperial Valley are not long lived. The current fault geometry and basement morphology suggest northwestward growth of the Imperial fault and migration of the Brawley Seismic Zone. It is suggested that this migration is a manifestation of the propagation of the Gulf of California rift system into the North American continent.

  3. Age constraints for the present fault configuration in the Imperial Valley, California: Evidence for northwestward propagation of the Gulf of California rift system

    NASA Technical Reports Server (NTRS)

    Larsen, Shawn; Reilinger, Robert

    1990-01-01

    Releveling and other geophysical data for the Imperial Valley of southern California suggest the northern section of the Imperial-Brawley fault system, which includes the Mesquite Basin and Brawley Seismic Zone, is much younger than the 4 to 5 million year age of the valley itself. A minimum age of 3000 years is calculated for the northern segment of the Imperial fault from correlations between surface topography and geodetically observed seismic/interseismic vertical movements. Calculations of a maximum age of 80,000 years is based upon displacements in the crystalline basement along the Imperial fault, inferred from seismic refraction surveys. This young age supports recent interpretations of heat flow measurements, which also suggest that the current patterns of seismicity and faults in the Imperial Valley are not long lived. The current fault geometry and basement morphology suggest northwestward growth of the Imperial fault and migration of the Brawley Seismic Zone. It is suggested that this migration is a manifestation of the propagation of the Gulf of California rift system into the North American continent.

  4. Heat flow and geothermal potential of the East Mesa KGRA, Imperial Valley, California

    NASA Technical Reports Server (NTRS)

    Swanberg, C. A.

    1974-01-01

    The East Mesa KGRA (Known Geothermal Resource Area) is located in the southeast part of the Imperial Valley, California, and is roughly 150 kilometers square in areal extent. A new heat flow technique which utilizes temperature gradient measurements across best clays is presented and shown to be as accurate as conventional methods for the present study area. Utilizing the best clay gradient technique, over 70 heat flow determinations have been completed within and around the East Mesa KGRA. Background heat flow values range from 1.4 to 2.4 hfu (1 hfu = .000001 cal. per square centimeter-second) and are typical of those throughout the Basin and Range province. Heat flow values for the northwest lobe of the KGRA (Mesa anomaly) are as high as 7.9 hfu, with the highest values located near gravity and seismic noise maxima and electrical resistivity minima. An excellent correlation exists between heat flow contours and faults defined by remote sensing and microearthquake monitoring.

  5. Engineering aspects of geothermal development with emphasis on the Imperial Valley of California

    NASA Technical Reports Server (NTRS)

    Goldsmith, M.

    1978-01-01

    This review was prepared in support of a geothermal planning activity of the County of Imperial. Engineering features of potential geothermal development are outlined. Acreage requirements for drilling and powerplants are estimated, as are the costs for wells, fluid transmission pipes, and generating stations. Rough scaling relationships are developed for cost factors as a function of reservoir temperature. Estimates are made for cooling water requirements, and possible sources of cooling water are discussed. Availability and suitability of agricultural wastewater for cooling are emphasized. The utility of geothermal resources for fresh water production in the Imperial Valley is considered.

  6. Assessment of geothermal development in the Imperial Valley of California. Volume 1. Environment, health, and socioeconomics

    SciTech Connect

    Layton, D.

    1980-07-01

    Utilization of the Imperial Valley's geothermal resources to support energy production could be hindered if environmental impacts prove to be unacceptable or if geothermal operations are incompatible with agriculture. To address these concerns, an integrated environmental and socioeconomic assessment of energy production in the valley was prepared. The most important impacts examined in the assessment involved air quality changes resulting from emissions of hydrogen sulfide, and increases in the salinity of the Salton Sea resulting from the use of agricultural waste waters for power plant cooling. The socioeconomics consequences of future geothermal development will generally be beneficial. (MHR)

  7. Timing and slip for prehistoric earthquakes on the Superstition Mountain Fault, Imperial Valley, southern California

    NASA Astrophysics Data System (ADS)

    Gurrola, Larry D.; Rockwell, Thomas K.

    1996-03-01

    Trenches excavated across the Superstition Mountain fault in the Imperial Valley, California, have exposed evidence for four prehistorical earthquakes preserved in displaced lacustrine stratigraphy associated with ancient Lake Cahuilla. The presence of shoreline peat accumulations along with abundant detrital charcoal allows for high-precision age determination of some stratigraphic units, thereby providing constraints on the timing of three of the paleoearthquakes. These three events occurred within a 480- to 820-year interval during the past 1200 years. The most recent earthquake (event 1) occurred during a fluvial phase of deposition between A.D. 1440-1637, immediately prior to the inundation of the Cahuilla basin at about A.D. 1480 and 1660. A channel margin was offset 2.2 +0.4/-0.15 m in this rupture, suggesting an earthquake with a magnitude ≥7. The penultimate event (event 2) also occurred during fluvial deposition after A.D. 1280 but before another lakestand at A.D. 1440-1640. Lateral slip could not be resolved for event 2. However, based on juxtaposition of dissimilar units and the amount of deformation produced by this event, it is presumed that this was also a large earthquake. The timing of event 3 is constrained to have occurred between about A.D. 820 and 1280. This event is represented by several fractures and small displacements that rupture up to a distinct stratigraphic level or event horizon. Slip was not resolved for this event. Finally, the timing of event 4 is very poorly constrained to between A.D. 964 and 4670 B.C. Undoubtedly, many events may have occurred during this period. Notably, the past three earthquakes occurred within a period of less than 820 years, and it has been over 350 years since the last earthquake.

  8. Assessment of geothermal development in the Imperial Valley of California. Volume 2. Environmental control technology

    SciTech Connect

    Morris, W.; Hill, J.

    1980-07-01

    Environmental control technologies are essential elements to be included in the overall design of Imperial Valley geothermal power systems. Environmental controls applicable to abatement of hydrogen sulfide emissions, cooling tower drift, noise, liquid and solid wastes, and induced subsidence and seismicity are assessed here. For optimum abatement of H{sub 2}S under a variety of plant operating conditions, removal of H{sub 2}S upstream of the steam turbine is recommended. The environmental impact of cooling tower drift will be closely tied to the quality of cooling water supplies. Conventional noise abatement procedures can be applied and no special research and development are needed. Injection technology constitutes the primary and most essential environmental control and liquid waste disposal technology for Imperial Velley geothermal operations. Subsurface injection of fluids is the primary control for managing induced subsidence. Careful maintenance of injection pressure is expected to control induced seismicity. (MHR)

  9. Comparison of multispectral remote-sensing techniques for monitoring subsurface drain conditions. [Imperial Valley, California

    NASA Technical Reports Server (NTRS)

    Goettelman, R. C.; Grass, L. B.; Millard, J. P.; Nixon, P. R.

    1983-01-01

    The following multispectral remote-sensing techniques were compared to determine the most suitable method for routinely monitoring agricultural subsurface drain conditions: airborne scanning, covering the visible through thermal-infrared (IR) portions of the spectrum; color-IR photography; and natural-color photography. Color-IR photography was determined to be the best approach, from the standpoint of both cost and information content. Aerial monitoring of drain conditions for early warning of tile malfunction appears practical. With careful selection of season and rain-induced soil-moisture conditions, extensive regional surveys are possible. Certain locations, such as the Imperial Valley, Calif., are precluded from regional monitoring because of year-round crop rotations and soil stratification conditions. Here, farms with similar crops could time local coverage for bare-field and saturated-soil conditions.

  10. Interseismic Strain Accumulation in the Imperial Valley and Implications for Triggering of Large Earthquakes in Southern California

    NASA Astrophysics Data System (ADS)

    Crowell, B. W.; Bock, Y.; Sandwell, D. T.

    2009-12-01

    From February, 2008 to March, 2009, we performed three rapid-static Global Positioning System (GPS) surveys of 115 geodetic monuments stretching from the United States-Mexico border into the Coachella Valley using the method of instantaneous positioning. The monuments are located in key areas near the Imperial, Superstition Hills, San Jacinto, San Andreas and Brawley Faults with nominal baselines generally less than 10 km. We perform a bicubic spline interpolation on the crustal motion vectors from the campaign measurements and 1005 continuous GPS monuments in western North America and solve for the velocity gradient tensor to look at the maximum shear strain, dilatation and rotation rates in the Imperial Valley. We then compare our computed strain field to that computed using the Southern California Earthquake Center Crustal Motion Map 3.0, which extends through 2003 and includes 840 measurements. We show that there is an interseismic strain transient that corresponds to an increase in the maximum shear strain rate of 0.7 μstrain/yr near Obsidian Buttes since 2003 along a fault referred to as the Obsidian Buttes Fault (OBF). A strong subsidence signal of 27 mm/yr and a left-lateral increase of 10 mm/yr are centered along the OBF. Changes in the dilatation and rotation rates confirm the increase in left-lateral motion, as well as infer a strong increase in spreading rate in the southern Salton Sea. The increase in spreading rate has caused an accelerated slip rate along the southern San Andreas near Durmid Hill as evidenced by continuous GPS, which has the potential for earthquake triggering.

  11. Evaluation of remote sensing in control of pink bollworm in cotton. [Imperial Valley, Coachella Valley, and Palo Verde Valley, California

    NASA Technical Reports Server (NTRS)

    Lewis, L. N. (Principal Investigator); Coleman, V. B.; Johnson, C. W.

    1974-01-01

    The author has identified the following significant results. This investigation is to evaluate the use of a satellite in monitoring the cotton production regulation program of the State of California as an aid in controlling pink bollworm infestation in the southern deserts of California. Color combined images of ERTS-1 multispectral images simulating color infrared are being used for crop identification. The status of each field (crop, bare, harvested, wet, plowed) is mapped from the imagery and is then compared to ground survey information taken at the time of ERTS-1 overflights. A computer analysis has been performed to compare field and satellite data to a crop calendar. Correlation to date has been 97% for field condition. Actual crop identification varies; cotton identification is only 63% due to lack of full season coverage.

  12. Seismic calibration shots conducted in 2009 in the Imperial Valley, southern California, for the Salton Seismic Imaging Project (SSIP)

    USGS Publications Warehouse

    Murphy, Janice; Goldman, Mark; Fuis, Gary; Rymer, Michael; Sickler, Robert; Miller, Summer; Butcher, Lesley; Ricketts, Jason; Criley, Coyn; Stock, Joann; Hole, John; Chavez, Greg

    2011-01-01

    Rupture of the southern section of the San Andreas Fault, from the Coachella Valley to the Mojave Desert, is believed to be the greatest natural hazard facing California in the near future. With an estimated magnitude between 7.2 and 8.1, such an event would result in violent shaking, loss of life, and disruption of lifelines (freeways, aqueducts, power, petroleum, and communication lines) that would bring much of southern California to a standstill. As part of the Nation's efforts to prevent a catastrophe of this magnitude, a number of projects are underway to increase our knowledge of Earth processes in the area and to mitigate the effects of such an event. One such project is the Salton Seismic Imaging Project (SSIP), which is a collaborative venture between the United States Geological Survey (USGS), California Institute of Technology (Caltech), and Virginia Polytechnic Institute and State University (Virginia Tech). This project will generate and record seismic waves that travel through the crust and upper mantle of the Salton Trough. With these data, we will construct seismic images of the subsurface, both reflection and tomographic images. These images will contribute to the earthquake-hazard assessment in southern California by helping to constrain fault locations, sedimentary basin thickness and geometry, and sedimentary seismic velocity distributions. Data acquisition is currently scheduled for winter and spring of 2011. The design and goals of SSIP resemble those of the Los Angeles Region Seismic Experiment (LARSE) of the 1990's. LARSE focused on examining the San Andreas Fault system and associated thrust-fault systems of the Transverse Ranges. LARSE was successful in constraining the geometry of the San Andreas Fault at depth and in relating this geometry to mid-crustal, flower-structure-like decollements in the Transverse Ranges that splay upward into the network of hazardous thrust faults that caused the 1971 M 6.7 San Fernando and 1987 M 5

  13. First report of an ipomovirus infecting cucurbits in the Imperial Valley of California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the fall of 2014, pumpkin plants grown at the University of California Desert Research Extension Center (DREC) in Holtville, CA showed severe stunting, leaf yellowing, crumpling, and epinasty. These plants were also infested with high populations of B. tabaci. RT-PCR and PCR tests performed on le...

  14. Assessment of the impact on crops of effluent gases from geothermal energy development in the Imperial Valley, California

    SciTech Connect

    Kercher, J.R.

    1982-01-01

    The potential impact of regionally dispersed sources of geothermal gaseous effluents on crops in the Imperial Valley was assessed. A detailed model of the photosynthesis and growth of sugar beets fumigated by H/sub 2/S and CO/sub 2/ and generalized from the model calculations to other crops was used. Model calculations were made with estimates of time series of expected ground-level concentrations of H/sub 2/S and CO/sub 2/ calculated by the air quality assessment element of the Imperial Valley Environmental Project (IVEP) at 22 locations around the valley. The model calculations also used time series data of meteorological variables such as air temperature, solar radiation, and relative humidity, which were measured by the air quality baseline element in the field of the Imperial Valley. Results indicate that, in the absence of interactions with other ambient pollutant gases, all location would experience an increase (from slight to significant) in total growth of sugar beets. Seven locations will experience an increase of at least 10%. The emissions rate at which negative effects cancel out the benefits of H/sub 2/S fertilization was calculated; in the worst case, emission rates are expected to be no more than 1/13 of this crossover rate. The expected emission rate will be less than that necessary for negative effects on the most sensitive species (such as alfalfa) by a factor of 4. Similar results for other crops are summarized in the report. If CO/sub 2/ emissions are increased proportionately, the dominance of deleterious effects is not expected to occur, even under maximum development as set forth in IVEP scenario projections. 8 figures, 6 tables.

  15. Assessment of the impact on crops of effluent gases from geothermal energy development in the Imperial Valley, California

    SciTech Connect

    Kercher, J.R.

    1981-05-22

    We have assessed the potential impact of regionally dispersed sources of geothermal gaseous effluents on crops in the Imperial Valley. We used a detailed model of the photosynthesis and growth of sugar beets fumigated by H/sub 2/S and CO/sub 2/ and generalized from the model calculations to other crops. Model calculations were made with estimates of time series of expected ground-level concentrations of H/sub 2/S and CO/sub 2/ calculated by the Air Quality Assessment element of the Imperial Valley Environmental Project (IVEP) at 22 locations around the valley. Results indicate that in the absence of interactions with other ambient pollutant gases, all locations would experience an increase (from slight to significant) in total growth of sugar beets. Seven locations will experience an increase of at least 10%. We calculated the emissions rate at which negative effects cancel out the benefits of H/sub 2/S fertilization; in the worst case, emission rates are expected to be no more than 1/13 this crossover rate. The expected emission rate will be less than that necessary for negative effects on the most sensitive species (such as alfalfa) by a factor of 4. Similar results for other crops are summarized in the report. If CO/sub 2/ emissions are increased proportionately, the dominance of deleterious effects is not expected to occur even under maximum development as set forth in IVEP scenario projections. 23 references, 8 figures, 6 tables.

  16. Anomalous record of October 15, 1979, Imperial Valley, California, earthquake from Coachella Canal Engine House No. 4

    USGS Publications Warehouse

    Bycroft, G.N.

    1981-01-01

    A recording obtained at the Coachella Canal Engine House No. 4 of the October 15, 1979, Imperial Valley earthquake shows a dominant 2 Hz frequency. This feature is very unusual and an attempt has been made to determine if the recording is real or spurious. As the pumping station is a small heavily constructed bunker type of structure located on material of low shear wave velocity it was considered likely that soil-structure interaction might be responsible for the 2 Hz component. However, both an experimental and theoretical investigation fail to establish this. This report describes the theoretical investigation. The experimental investigation is described in a separate open-file report.

  17. Imperial Contradictions: Is the Valley a Watershed, Region, or Cyborg?

    ERIC Educational Resources Information Center

    Rudy, Alan P.

    2005-01-01

    Is California's Imperial Valley a watershed? If so, at what level and by what topographic logic? Is it a region? If so, at what level and by what geographic logic? Are its boundaries natural, political, or multivalent on different scales? In short, this essay looks at the special (re)production of environmental conditions within a cyborg world.…

  18. Use of long-term tritium records from the Colorado River to determine timescales for hydrologic processes associated with irrigation in the Imperial Valley, California

    USGS Publications Warehouse

    Michel, R.L.; Schoeder, R.A.

    1994-01-01

    Tritium records were used to study hydrologic processes associated with irrigation and drainage in the Imperial Valley, a 2000-km2 agricultural area in the southeastern California desert. Tritium was analyzed in surface water, ground water, soil-pore water and drain water, and the results were compared to the historical record of tritium in the Colorado River. The Colorado River record was reconstructed using a simple reservoir model and precipitation data in the Colorado River Basin for the period prior to 1965, and from continuous measurements in the river for 1965-1988. This historical record is especially useful in the arid Imperial Valley because recent agricultural development has been entirely dependent on irrigation water diverted from the Colorado River and local recharge is negligible. Results indicate that it takes about 5 a for irrigation drainage to move through the soil to a depth of 2-3 m. Drainwaters have a wide range in tritium concentrations because of varying degrees of influence from ground-water intrusion, and from rapid percolation of irrigation through preferred pathways. The net result is that drainwater from about 40 fields had a range in tritium concentration similar to that of the Colorado River over the last 9 a (1980-1988), a period during which tritium concentration was declining about 15% annually in the river. ?? 1994.

  19. 77 FR 2496 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-18

    ... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management District and Imperial Valley Air Pollution Control District AGENCY: Environmental Protection... Valley Air Quality Management District (AVAQMD) and Imperial County Air Pollution Control...

  20. Frequency distribution of mineral elements in samples of alfalfa and sugar beet leaves obtained from a common field in Imperial Valley, California

    SciTech Connect

    Wallace, A.; Romney, E.M.; Kinnear, J.

    1982-07-01

    Baseline measurements were made of mineral composition of alfalfa (Medicago sativa L.) and sugar beets (Beta vulgaris L.) from one field each in the Imperial Valley of California. The fields are in a geothermal area being developed for energy production, and the purpose of the investigation was to ascertain variablility within a relatively large number of samples from a common area, so that subsequent samplings could be made to satisfactorily detect whether there were changes resulting from the geothermal activity. Means, standard deviations, frequency distribution, correlations, cluster trees, and other statistics were examined for over 20 elements at each site.Most elements were normally distributed, but there was three- to fourfold range in the concentration for each.

  1. Earthquake History of the Northern Imperial Fault, Imperial Valley, California, since the last Lake Cahuilla Highstand, circa A.D. 1680

    NASA Astrophysics Data System (ADS)

    Meltzner, A. J.; Rockwell, T. K.; Verdugo, D. M.

    2003-12-01

    The Imperial fault (IF) is the only fault in southern California to have ruptured in two major earthquakes in the 20th century. In 1940, it ruptured end-to-end (both north and south of the international border) in an M 6.9 earthquake, and in 1979, the northern segment of the fault (north of the border) ruptured again in an M 6.4 event. Slip in 1940 was highest (5-6 m) along the central portion of the fault and lowest (<1 m) along the northern portion, with a high slip gradient between these two segments just north of the border. The 1979 earthquake involved surface rupture along only the northern 30 km of the fault, with dextral offsets being <1 m and being nearly identical to 1940 offsets along the northern 20 km of the rupture. The similarities and differences of the two events led Sieh (1996) to propose a "slip-patch model" for the Imperial fault, whereby the fault ruptures with frequent moderate earthquakes along its northern end, like in 1979, and with less frequent larger events like 1940 along its entire length. According to the model, the central patch, which experienced high slip in 1940 and did not rupture in 1979, would rupture with relatively infrequent events (roughly every 260 years) with typically 5-6 m of slip per event; meanwhile, the northern patch, which corresponds to the 1979 rupture, would rupture more frequently (roughly every 40 years) with up to 1 m of slip per event. This model is consistent with the slip distribution observed in 1940 and in 1979. Paleoseismic investigations along the central patch also support this model, as the penultimate event there occurred shortly after the last Lake Cahuilla (LC) highstand at around A.D. 1680 (Thomas and Rockwell, 1996). Prior to the present investigation, however, there were no data on events prior to 1940 on the northern patch, which could serve to either support or refute the slip-patch model. We have opened a trench across the IF south of Harris Road, adjacent to Mesquite Basin, where the fault

  2. Efficacy of CC traps and seasonal activity of adult Bemisia argentifolii (Homoptera: Aleyrodidae) in Imperial and Palo Verde Valleys, California.

    PubMed

    Chu, C C; Henneberry, T J; Natwick, E T; Ritter, D; Birdsall, S L

    2001-02-01

    Adult whitefly Bemisia argentifolii Bellows & Perring trap (CC trap) catches were compared with suction type trap catches. CC trap catches were significantly correlated to the suction trap catches. Higher numbers of B. argentifolii adults were caught in CC traps oriented toward an untreated, B. argentifolii-infested, cotton field as compared with traps oriented toward Bermuda grass fields, farm roads, or fallow areas. CC trap catches at five heights above ground (from 0 to 120 cm) were significantly related to each other in choice and no-choice studies. CC trap catches were low in the Imperial and Palo Verde Valleys from late October to early June each of 1996, 1997, and 1998. Trap catches increased with increasing seasonal air temperatures and host availability. Trap catches were adversely affected by wind and rain. Abrupt trap catch increases of 40- to 50-fold for 1-2 d in late June to early July followed by abrupt decreases in adult catches suggest migrating activity of adults from other nearby crop sources. PMID:11233132

  3. A system of regional agricultural land use mapping tested against small scale Apollo 9 color infrared photography of the Imperial Valley (California)

    USGS Publications Warehouse

    Johnson, Claude W.; Browden, Leonard W.; Pease, Robert W.

    1969-01-01

    Interpretation results of the small scale ClR photography of the Imperial Valley (California) taken on March 12, 1969 by the Apollo 9 earth orbiting satellite have shown that world wide agricultural land use mapping can be accomplished from satellite ClR imagery if sufficient a priori information is available for the region being mapped. Correlation of results with actual data is encouraging although the accuracy of identification of specific crops from the single image is poor. The poor results can be partly attributed to only one image taken during mid-season when the three major crops were reflecting approximately the same and their ClR image appears to indicate the same crop type. However, some incapacity can be attributed to lack of understanding of the subtle variations of visual and infrared color reflectance of vegetation and surrounding environment. Analysis of integrated color variations of the vegetation and background environment recorded on ClR imagery is discussed. Problems associated with the color variations may be overcome by development of a semi-automatic processing system which considers individual field units or cells. Design criteria for semi-automatic processing system are outlined.

  4. Imperial Valley College 2+2+2 Project Handbook.

    ERIC Educational Resources Information Center

    Marquez, Ralph

    This handbook of the Imperial Valley College (IVC) 2+2+2 Project provides an overview of the development of an articulated education program for business and law enforcement careers, involving six local high schools and San Diego State University, Imperial Valley Campus. Following a brief introduction to the 2+2+2 project in section I, section II…

  5. A Galerkin, finite-element analysis of steady-state flow and heat transport in the shallow hydrothermal system in the East Mesa area, Imperial Valley, California

    USGS Publications Warehouse

    Miller, R.E.

    1977-01-01

    A steady-state simulation model was applied to the shallow hydrothermal system in the East Mesa area of Imperial Valley, Calif. The steady-state equations of flow and heat transport were solved by use of a Galerkin, finite-element method. A solution was obtained by iterating between the temperature and pressure equations, using updated densities and viscosities. Temperature and pressure were obtained for each node, and corresponding head values were calculated. The simulated temperature and pressure patterns correlated well with the observed patterns. Additional data, mainly from test drilling, would be required for construction of a similar model of the deep hydrothermal system.

  6. Pesticides in Water and Suspended Sediment of the Alamo and New Rivers, Imperial Valley/Salton Sea Basin, California, 2006-2007

    USGS Publications Warehouse

    Orlando, James L.; Smalling, Kelly L.; Kuivila, Kathryn M.

    2008-01-01

    Water and suspended-sediment samples were collected at eight sites on the Alamo and New Rivers in the Imperial Valley/Salton Sea Basin of California and analyzed for both current-use and organochlorine pesticides by the U.S. Geological Survey. Samples were collected in the fall of 2006 and spring of 2007, corresponding to the seasons of greatest pesticide use in the basin. Large-volume water samples (up to 650 liters) were collected at each site and processed using a flow-through centrifuge to isolate suspended sediments. One-liter water samples were collected from the effluent of the centrifuge for the analysis of dissolved pesticides. Additional samples were collected for analysis of dissolved organic carbon and for suspended-sediment concentrations. Water samples were analyzed for a suite of 61 current-use and organochlorine pesticides using gas chromatography/mass spectrometry. A total of 25 pesticides were detected in the water samples, with seven pesticides detected in more than half of the samples. Dissolved concentrations of pesticides observed in this study ranged from below their respective method detection limits to 8,940 nanograms per liter (EPTC). The most frequently detected compounds in the water samples were chlorpyrifos, DCPA, EPTC, and trifluralin, which were observed in more than 75 percent of the samples. The maximum concentrations of most pesticides were detected in samples from the Alamo River. Maximum dissolved concentrations of carbofuran, chlorpyrifos, diazinon, and malathion exceeded aquatic life benchmarks established by the U.S. Environmental Protection Agency for these pesticides. Suspended sediments were analyzed for 87 current-use and organochlorine pesticides using microwave-assisted extraction, gel permeation chromatography for sulfur removal, and either carbon/alumina stacked solid-phase extraction cartridges or deactivated Florisil for removal of matrix interferences. Twenty current-use pesticides were detected in the suspended

  7. Aquaculture in the Imperial Valley -- A geothermal success story

    SciTech Connect

    Rafferty, K.

    1999-03-01

    The Salton Sea and Imperial Valley area of southern California has long been recognized as a hot spot of geothermal development. In the geothermal industry, this area has for some time been synonymous with electric power generation projects. Starting with the first plant in East Mesa in 1979, geothermal power has increased over the years to the present 400+ MW of installed capacity in the three primary areas of Salton Sea, Heber and East Mesa. Although most in the industry are aware of the millions of kilowatt-hours annually produced in this desert oasis of development, they remain surprisingly uninformed about the Valley`s other geothermal industry -- aquaculture. At present, there are approximately 15 fish farming (or aquaculture) operations clustered, for the most part, around the Salton Sea. All of these farms use geothermal fluids to control the temperature of the fish culture facilities so as to produce larger fish in a shorter period of time and to permit winter production which would otherwise not be possible. In aggregate, these farms produce on the order of 10,000,000 lbs of fish per year most of which is sold into the California market. Principle species are catfish, striped bass and tilapia. For the past several years, tilapia has been the fastest growing part of the aquaculture industry. In 1996, the total US consumption of tilapia was 62,000 lbs. Of this, only 16,000,000 lbs (26%) was domestically produced and the balance imported. The primary market for the fish on the West Coast is among the Asian-American populations in the major cities. Fish are shipped and sold liver at the retail level.

  8. San Diego Gas and Electric Company Imperial Valley geothermal activities

    NASA Technical Reports Server (NTRS)

    Hinrichs, T. C.

    1974-01-01

    San Diego Gas and Electric and its wholly owned subsidiary New Albion Resources Co. have been affiliated with Magma Power Company, Magma Energy Inc. and Chevron Oil Company for the last 2-1/2 years in carrying out geothermal research and development in the private lands of the Imperial Valley. The steps undertaken in the program are reviewed and the sequence that must be considered by companies considering geothermal research and development is emphasized. Activities at the south end of the Salton Sea and in the Heber area of Imperial Valley are leading toward development of demonstration facilities within the near future. The current status of the project is reported.

  9. California: San Joaquin Valley

    Atmospheric Science Data Center

    2014-05-15

    article title:  Fog and Haze in California's San Joaquin Valley   ... is noted for its hazy overcasts and a low, thick ground fog known as the Tule. Owing to the effects of the atmosphere on reflected ... as the angle of view changes. An area of thick, white fog in the San Joaquin Valley is visible in all three of the images. However, ...

  10. Imperial Valley's proposal to develop a guide for geothermal development within its county

    NASA Technical Reports Server (NTRS)

    Pierson, D. E.

    1974-01-01

    A plan to develop the geothermal resources of the Imperial Valley of California is presented. The plan consists of development policies and includes text and graphics setting forth the objectives, principles, standards, and proposals. The plan allows developers to know the goals of the surrounding community and provides a method for decision making to be used by county representatives. A summary impact statement for the geothermal development aspects is provided.

  11. Pliocene Invertebrates From the Travertine Point Outcrop of the Imperial Formation, Imperial County, California

    USGS Publications Warehouse

    Powell, Charles L.

    2008-01-01

    Forty-four invertebrate taxa, including one coral, 40 mollusks (30 bivalves and 10 gastropods), and three echinoids are recognized from a thin marine interval of the Imperial Formation near Travertine Point, Imperial County, California. The Travertine Point outcrop lies about midway between exposures of the Imperial Formation around Palm Springs, Riverside County, and exposures centered at Coyote Mountain in Imperial and San Diego Counties. Based on faunal comparisons, the Travertine Point outcrop corresponds to the Imperial and San Diego outcrops. The Travertine Point fauna is inferred to have lived in subtropical to tropical waters at littoral to inner sublittorial (<50 m) water depths. Coral and molluscan species from the Travertine Point outcrop indicate a Pliocene age. Two extant bivalve mollusks present have not previously been reported as fossils Anadara reinharti and forms questionably referred to Dosinia semiobliterata.

  12. Trap catches of the sweetpotato whitefly (Homoptera: Aleyrodidae) in the Imperial Valley, Caiifornia, from 1996 to 2002

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An outbreak of the sweetpotato whitefly, Bemisia tabaci (Gennadius), biotype B occurred in the Imperial Valley, California in 1991. The insects destroyed melon crops and seriously damaged other vegetables, ornamentals and row crops. As a result of the need for sampling technology, we developed a w...

  13. Modeling Events in the Lower Imperial Valley Basin

    NASA Astrophysics Data System (ADS)

    Tian, X.; Wei, S.; Zhan, Z.; Fielding, E. J.; Helmberger, D. V.

    2010-12-01

    The Imperial Valley below the US-Mexican border has few seismic stations but many significant earthquakes. Many of these events, such as the recent El Mayor-Cucapah event, have complex mechanisms involving a mixture of strike-slip and normal slip patterns with now over 30 aftershocks with magnitude over 4.5. Unfortunately, many earthquake records from the Southern Imperial Valley display a great deal of complexity, ie., strong Rayleigh wave multipathing and extended codas. In short, regional recordings in the US are too complex to easily separate source properties from complex propagation. Fortunately, the Dec 30 foreshock (Mw=5.9) has excellent recordings teleseismically and regionally, and moreover is observed with InSAR. We use this simple strike-slip event to calibrate paths. In particular, we are finding record segments involving Pnl (including depth phases) and some surface waves (mostly Love waves) that appear well behaved, ie., can be approximated by synthetics from 1D local models and events modeled with the Cut-and-Paste (CAP) routine. Simple events can then be identified along with path calibration. Modeling the more complicated paths can be started with known mechanisms. We will report on both the aftershocks and historic events.

  14. Further Resolution of Past Earthquake Surface Ruptures at the Carrizo Wash Site, Superstition Mountain Strand of the San Jacinto Fault, Imperial Valley, Southern California.

    NASA Astrophysics Data System (ADS)

    Verdugo, D.; Ragona, D. E.; Rockwell, T. K.

    2005-12-01

    We present results from new trench exposures in Carrizo Wash along the northernmost part of the Superstition Mountain strand (SMF) of the San Jacinto Fault, southern California. Prior paleoseismic work by Ragona (2003) recovered evidence for 7 earthquake events, 3 of which occurred in the past 1000 years. The most recent event produced only 15 cm of slip and is only recognized along the Coyote Creek Fault (CCF). The other two recognized events cumulatively produced nearly 6 m of slip. However, an erosional unconformity in the initial excavations removed evidence for at least one event, based on problematic correlations to nearby sites resulting from mismatches in both the number of recognized lake units as well as the relative stratigraphic position of events with respect to the lakes. The new trenches, south of the effects of the erosional channel, contain evidence for an additional event and an additional delta-lake sequence not present in the original exposures. The new event likely correlates to the penultimate event at the Northern Shoreline site (Gurrola and Rockwell, 1996). Thus, the observed 6 m of slip was mostly accommodated by three events, suggesting about 2 m of slip per event for large SMF ruptures. Our new observations also agree well with data from four other nearby trench sites along the CCF and SMF, and suggest that 1) the SMF has ruptured in only three large events in the past 1100 years, 2) at least two of these events are likely recognized along the CCF, indicating that the step-over between SMF and CCF is soft in large events, 3) most CCF ruptures do not propagate onto the SMF, indicating that the step-over is hard for small displacements, such as 1968-type events (30-50 cm of slip). These observations support the concept of segmentation but indicate that a perceived segment boundary may be transparent if slip exceeds a threshold value.

  15. Death Valley, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is an image of Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. The bright dots near the center of the image are corner refectors that have been set-up to calibrate the radar as the Shuttle passes overhead with the SIR-C/X-SAR system. The Jet Propulsion Laboratory alternative photo number is P-43883.

  16. Location of odor sources and the affected population in Imperial County, California

    SciTech Connect

    Hahn, J.L.

    1981-08-01

    This report is divided into four sections. The first two sections contain general background information on Imperial County. The third section is a general discussion of odor sources in Imperial County, and the fourth maps the specific odor sources, the expected areas of perception, and the affected populations. this mapping is done for the Imperial Valley and each of the four Imperial County KGRA's (Known Geothermal Resource Areas) where odor from the development of the geothermal energy may affect population.

  17. Steady state, near-source models of the Parkfield, Imperial Valley, and Mexicali Valley Earthquakes

    NASA Astrophysics Data System (ADS)

    Mendez, A. J.; Luco, J. E.

    1990-01-01

    Some of the gross characteristics of the rupture processes for the 1966 Parkfield, 1979 Imperial Valley, and 1980 Mexicali Valley earthquakes are determined by waveform inversion of near-source data employing a steady state dislocation model in a layered half-space. The forward model involves a piecewise-linear rupture front moving with a constant horizontal rupture velocity on a fault of infinite length and finite width. The inferred shapes for the rupture front and for the distribution of slip as a function of depth are consistent with previous results obtained by use of more general models. The results obtained show that a strong velocity pulse observed in the nearsource region can be modeled as the passage of the rupture front phase and that the supershear propagation of the rupture front in the sedimentary layers of the medium provides a mechanism for the generation of the observed large amplitudes.

  18. Geodetic observations of fault creep in the Imperial Valley: hidden faults, earthquake hazard and implications for frictional properties

    NASA Astrophysics Data System (ADS)

    Lindsey, E. O.; Fialko, Y. A.

    2014-12-01

    We present new observations of the pattern of fault creep and interseismic deformation in the Imperial Valley, California using a combination of multiple InSAR viewing geometries and survey-mode GPS. We combine more than 100 survey-mode GPS velocities (Crowell et al., 2013) with Envisat InSAR observations from descending tracks 84 and 356 and ascending tracks 77 and 306 (149 total acquisitions), processed using the Stanford Method for Persistent Scatterers (StaMPS) package (Hooper et al., 2007). The result is a dense map of surface velocities across the Imperial fault and surrounding areas. The data suggest that a previously little-known extension of the Superstition Hills fault through the town of El Centro may accommodate a significant portion of the slip previously attributed to the Imperial Fault. We investigate a suite of possible models for the transfer of this slip to the Imperial and Cerro Prieto faults to the south, yielding a range of plausible hazard scenarios. Finally, we compare the geodetic data to models of earthquake cycles with rate- and state-dependent friction to assess the implications for creep depth, moment accumulation rate, and recurrence interval of large events on these faults.

  19. California: Diamond Valley

    Atmospheric Science Data Center

    2014-05-15

    ... District began filling the reservoir with water from the Colorado River and Northern California. Water appears darker than the ... center is being built to protect these finds. The lower MISR image, from May 20, 2001 (Terra orbit 7564), is a false-color view ...

  20. 77 FR 13591 - Imperial Valley Solar Company (IVSC) 1, LLC; Supplemental Notice That Initial Market-Based Rate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ... Energy Regulatory Commission Imperial Valley Solar Company (IVSC) 1, LLC; Supplemental Notice That... supplemental notice in the above-referenced proceeding of Imperial Valley Solar Company (IVSC) 1, LLC's...Library system by clicking on the appropriate link in the above list. They are also available for...

  1. 78 FR 18581 - Imperial Valley Solar 1, LLC: Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... Energy Regulatory Commission Imperial Valley Solar 1, LLC: Supplemental Notice That Initial Market-Based... above-referenced proceeding, of Imperial Valley Solar 1, LLC's application for market-based rate... filings in the above-referenced proceeding(s) are accessible in the Commission's eLibrary system...

  2. Imperialism.

    ERIC Educational Resources Information Center

    Martz, Carlton

    2002-01-01

    This publication discusses issues related to imperialism. It examines the 1857 uprising against the British in India; examines how Hawaii became a U.S. territory at the turn of the 20th century; and reviews oil and U.S. energy policy, particularly the debate over drilling in the Arctic National Wildlife Refuge, an issue relevant to September 11,…

  3. Structure of the active rift zone and margins of the northern Imperial Valley from Salton Seismic Imaging Project (SSIP) data

    NASA Astrophysics Data System (ADS)

    Livers, A.; Han, L.; Delph, J. R.; White-Gaynor, A. L.; Petit, R.; Hole, J. A.; Stock, J. M.; Fuis, G. S.

    2012-12-01

    First-arrival refraction data were used to create a seismic velocity model of the upper crust across the actively rifting northern Imperial Valley and its margins. The densely sampled seismic refraction data were acquired by the Salton Seismic Imaging Project (SSIP) , which is investigating rift processes in the northern-most rift segment of the Gulf of California extensional province and earthquake hazards at the southern end of the San Andreas Fault system. A 95-km long seismic line was acquired across the northern Imperial Valley, through the Salton Sea geothermal field, parallel to the five Salton Butte volcanoes and perpendicular to the Brawley Seismic Zone and major strike-slip faults. Nineteen explosive shots were recorded with 100 m seismometer spacing across the valley and with 300-500 m spacing into the adjacent ranges. First-arrival travel times were picked from shot gathers along this line and a seismic velocity model was produced using tomographic inversion. Sedimentary basement and seismic basement in the valley are interpreted to be sediment metamorphosed by the very high heat flow. The velocity model shows that this basement to the west of the Brawley Seismic Zone is at ~4-km depth. The basement shallows to ~2-km depth in the active geothermal field and Salton Buttes volcanic field which locally coincide with the Brawley Seismic Zone. At the eastern edge of the geothermal field, the basement drops off again to ~3.5-km depth. The eastern edge of the valley appears to be fault bounded by the along-strike extension of the Sand Hills Fault, an inactive strike-slip fault. The seismic velocities to the east of the fault correspond to metamorphic rock of the Chocolate Mountains, different from the metamorphosed basement in the valley. The western edge of the valley appears to be fault bounded by the active Superstition Hills Fault. To the west of the valley, >4-km deep valley basement extends to the active Superstition Hills Fault. Basement then shallows

  4. Feasibility study report for the Imperial Valley Ethanol Refinery: a 14. 9-million-gallon-per-year ethanol synfuel refinery utilizing geothermal energy

    SciTech Connect

    Not Available

    1981-03-01

    The construction and operation of a 14,980,000 gallon per year fuel ethanol from grain refinery in the Imperial Valley of California is proposed. The Imperial Valley Ethanol Refinery (refinery) will use hot geothermal fluid from geothermal resources at the East Mesa area as the source of process energy. In order to evaluate the economic viability of the proposed Project, exhaustive engineering, cost analysis, and financial studies have been undertaken. This report presents the results of feasibility studies undertaken in geothermal resource, engineering, marketing financing, management, environment, and permits and approvals. The conclusion of these studies is that the Project is economically viable. US Alcohol Fuels is proceeding with its plans to construct and operate the Refinery.

  5. California's restless giant: the Long Valley Caldera

    USGS Publications Warehouse

    Hill, David P.; Bailey, Roy A.; Hendley, James W., II; Stauffer, Peter H.; Marcaida, Mae

    2014-01-01

    Scientists have monitored geologic unrest in the Long Valley, California, area since 1980. In that year, following a swarm of strong earthquakes, they discovered that the central part of the Long Valley Caldera had begun actively rising. Unrest in the area persists today. The U.S. Geological Survey (USGS) continues to provide the public and civil authorities with current information on the volcanic hazard at Long Valley and is prepared to give timely warnings of any impending eruption.

  6. Integrated Modeling of Water Policy Futures in the Imperial-Mexicali Valleys

    NASA Astrophysics Data System (ADS)

    Kjelland, M. K.; Forster, C. B.; Grant, W. E.; Collins, K.

    2004-12-01

    Divided by an international border, the Imperial-Mexicali Valleys (IMVs) are linked by shared history, natural resources, culture and economy. This region is experiencing changes driven by policy makers both within and outside the IMVs. The largest external decision, the Colorado River Quantification Settlement Agreement (QSA) of 2003, opens the door to a laboratory for studying the consequences of a massive transfer of agricultural water to municipal users. Two irrigation districts, two urban water agencies and the State of California have agreed to a 75 year of more than 30 million acre-feet of Colorado River water from agricultural to urban use. Although Imperial Valley farmers will be compensated for water conservation and land fallowing, the economic, environmental and social consequences are unclear. Farmers who fallow will likely cause a greater impact on local businesses and government than those choosing on-field water conservation. Reduced agricultural water use causes reduced flow of irrigation runoff, at higher salinity than before, to the Salton Sea that, in turn, impacts the population dynamics of Ichthyan and Avian species at the Salton Sea. Municipal wastewater discharged into the New River by Mexicali, Mexico is also an important source of inflow to the Salton Sea that will be reduce by plans to reclaim the wastewater for various uses, including cooling water for two new power plants in the Mexicali. A restoration program is funded to produce a Sea with much reduced surface area. But this approach may, in turn, lead to increases in windblown dust from the dry lakebed that will contribute to an air basin already designated as a federal nonattainment area for particulate emissions. Additional water will be conserved by lining the All American and Coachella canals. But, eliminating seepage from the All American canal reduces groundwater recharge to aquifers used by Mexican farmers. A complex interplay of water-related issues must be accounted for if

  7. 75 FR 8008 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ...EPA is proposing a limited approval and limited disapproval of revisions to the Imperial County Air Pollution Control District (ICAPCD) portion of the California State Implementation Plan (SIP). These revisions concern coarse particulate matter (PM10) emissions from sources of fugitive dust such as construction sites, unpaved roads, and disturbed soils in open and agricultural......

  8. 76 FR 26615 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-09

    .... SUMMARY: EPA is finalizing approval of revisions to the Imperial County Air Pollution Control District... various air pollution sources. We are approving local rules that regulate these emission sources under the... February 9, 2011 (76 FR 7142), EPA proposed to approve the following rules into the California SIP....

  9. Liquefaction and other ground failures in Imperial County, California, from the April 4, 2010, El Mayor-Cucapah earthquake

    USGS Publications Warehouse

    McCrink, Timothy P.; Pridmore, Cynthia L.; Tinsley, John C., III; Sickler, Robert R.; Brandenberg, Scott J.; Stewart, Jonathan P.

    2011-01-01

    The Colorado River Delta region of southern Imperial Valley, California, and Mexicali Valley, Baja California, is a tectonically dynamic area characterized by numerous active faults and frequent large seismic events. Significant earthquakes that have been accompanied by surface fault rupture and/or soil liquefaction occurred in this region in 1892 (M7.1), 1915 (M6.3; M7.1), 1930 (M5.7), 1940 (M6.9), 1950 (M5.4), 1957 (M5.2), 1968 (6.5), 1979 (6.4), 1980 (M6.1), 1981 (M5.8), and 1987 (M6.2; M6.8). Following this trend, the M7.2 El Mayor-Cucapah earthquake of April 4, 2010, ruptured approximately 120 kilometers along several known faults in Baja California. Liquefaction caused by the M7.2 El Mayor-Cucapah earthquake was widespread throughout the southern Imperial Valley but concentrated in the southwest corner of the valley, southwest of the city centers of Calexico and El Centro where ground motions were highest. Although there are few strong motion recordings in the very western part of the area, the recordings that do exist indicate that ground motions were on the order of 0.3 to 0.6g where the majority of liquefaction occurrences were found. More distant liquefaction occurrences, at Fites Road southwest of Brawley and along Rosita Canal northwest of Holtville were triggered where ground motions were about 0.2 g. Damage to roads was associated mainly with liquefaction of sandy river deposits beneath bridge approach fills, and in some cases liquefaction within the fills. Liquefaction damage to canal and drain levees was not always accompanied by vented sand, but the nature of the damage leads the authors to infer that liquefaction was involved in the majority of observed cases. Liquefaction-related damage to several public facilities - Calexico Waste Water Treatment Plant, Fig Lagoon levee system, and Sunbeam Lake Dam in particular - appears to be extensive. The cost to repair these facilities to prevent future liquefaction damage will likely be prohibitive. As

  10. 78 FR 37845 - Meeting of the Imperial Sand Dunes Recreation Area (ISDRA) Subgroup of the California Desert...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-24

    ... California Desert District Advisory Council SUMMARY: Notice is hereby given, in accordance with Public Laws 92-463 and 94-579, that the Imperial Sand Dunes Recreation Area Subgroup of the California Desert... filed in advance of the meeting for the California Desert District Advisory Council ISDRA Subgroup,...

  11. Provenance of alluvial fan deposits to constrain the mid-term offsets along a strike-slip active fault: the Elsinore fault in the Coyote Mountains, Imperial Valley, California.

    NASA Astrophysics Data System (ADS)

    Masana, Eulalia; Stepancikova, Petra; Rockwell, Thomas

    2013-04-01

    The lateral variation in rates along a fault and its constancy along time is a matter of discussion. To give light to this discussion, short, mid and long term offset distribution along a fault is needed. Many studies analyze the short-term offset distribution along a strike-slip fault that can be obtained by the analysis of offset features imprinted in the morphology of the near-fault area. We present an example on how to obtain the mid- to long-term offset values based on the composition of alluvial fans that are offset by the fault. The study area is on the southern tip of the Elsinore fault, which controls the mountain front of the Coyote Mountains (California). The Elsinore-Laguna Salada fault is part of the San Andreas fault (SAF) system, extending 250 km from the Los Angeles Basin southeastward into the Gulf of California, in Mexico. The slip-rate on the southern Elsinore fault is believed to be moderate based on recent InSAR observations, although a recent study near Fossil Canyon (southern Coyote Mountains) suggests a rate in the range of 1-2 mm/yr. For this study we processed the airborne LiDAR dataset (EarthScope Southern & Eastern California, SoCal) to map short to mid-term alluvial offsets. We reprocessed the point clouds to produce DEMs with 0.5m and 0.25m grids and we varied the insolation angles to illuminate the various fault strands and the offset features. We identified numerous offset features, such as rills, channel bars, channel walls, alluvial fans, beheaded channels and small erosional basins that varied in displacement from 1 to 350 m. For the mid- to long-term offsets of the alluvial fans we benefited from the diverse petrological composition of their sources. Moreover, we recognized that older alluvium, which is offset by greater amounts, is in some cases buried beneath younger alluvial fan deposits and separated by buried soils. To determine the source canyon of various alluvial elements, we quantified the clast assemblage of each source

  12. Environmental assessmental, geothermal energy, Heber geothermal binary-cycle demonstration project: Imperial County, California

    SciTech Connect

    Not Available

    1980-10-01

    The proposed design, construction, and operation of a commercial-scale (45 MWe net) binary-cycle geothermal demonstration power plant are described using the liquid-dominated geothermal resource at Heber, Imperial County, California. The following are included in the environmental assessment: a description of the affected environment, potential environmental consequences of the proposed action, mitigation measures and monitoring plans, possible future developmental activities at the Heber anomaly, and regulations and permit requirements. (MHR)

  13. Mineral resources of the North Algodones Dunes Wilderness Study Area (CDCA-360), Imperial County, California

    SciTech Connect

    Smith, R.S.U.; Yeend, W.; Dohrenwend, J.C.; Gese, D.D.

    1984-01-01

    This report presents the results of a mineral survey of the North Algodones Dunes Wilderness Study Area (CDCA-360), California Desert Conservation Area, Imperial County, California. The potential for undiscovered base and precious metals, and sand and gravel within the North Algodones Dunes Wilderness Study Area is low. The study area has a moderate potential for geothermal energy. One small sand-free area between the Coachella Canal and the west edge of the dune field would probably be the only feasible exploration site for geothermal energy. The study area has a moderate to high potential for the occurrence of undiscovered gas/condensate within the underlying rocks. 21 refs.

  14. Recent landscape change in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Soulard, C. E.; Wilson, T. S.

    2012-12-01

    Long term monitoring of land use and land cover in California's intensively farmed Central Valley reveals several key physical and socioeconomic factors driving landscape change. As part of the USGS Land Cover Trends Project, we analyzed modern land-use/land-cover change for the California Central Valley ecoregion between 2000 and 2010, monitoring annual change between 2005 and 2010, while creating two new change intervals (2000-2005 and 2005-2010) to update the existing 27-year, interval-based analysis. Between 2000 and 2010, agricultural lands fluctuated due to changes in water allocations and emerging drought conditions, or were lost permanently to development (240 square km). Land-use pressure from agriculture and development also led to a decline in grasslands and shrublands across the region (280 square km). Overall, 400 square km of new developed lands were added in the first decade of the 21st century. From 2007 to 2010, development only expanded by 50 square km, coinciding with defaults in the banking system, the onset of historic foreclosure crisis in California and the global economic downturn. Our annual LULC change estimates capture landscape-level change in response to regional policy changes, climate, and fluctuations (e.g., growth or decline) in the national and global economy. The resulting change data provide insights into the drivers of landscape change in the California Central Valley and the combination of two consistent mapping efforts represents the first continuous, 37-year endeavor of its kind.

  15. Source characterization of major emission sources in the imperial and Mexicali Valleys along the US/Mexico border.

    PubMed

    Watson, J G; Chow, J C

    2001-08-10

    Chemical profiles for particle emissions are needed for source apportionment studies using the chemical mass balance (CMB) receptor model. Source measurements of geological sources, motor vehicle exhaust, vegetative burning (e.g. asparagus, field burning, charbroil cooking), and industrial sources (e.g. oil-fueled glass plant, manure-fueled power plants) were acquired as part of the Imperial/Mexicali Valley Cross Border PM10 Transport Study in 1992. Six different source sampling techniques (i.e. hot- and diluted-exhaust sampling, ground-based source sampling, particle sweeping/grab sampling, vacuum sampling, and laboratory resuspension sampling) were applied to acquire filter samples of PM 2.5 and PM10 (particulate matter with aerodynamic diameters < 2.5 and 10 microm, respectively). Filter samples were analyzed for mass by gravimetry, elements (Na to U) by X-ray fluorescence, anions (Cl(-), NO3(-), SO4(=)) by ion chromatography, ammonium (NH4(+)) by automated colorimetry, soluble sodium (Na+) and potassium (K+) by atomic absorption spectrophotometry, and organic and elemental carbon (OC, EC) by thermal/optical reflectance. Concentration data were acquired for a total of approximately 50 chemical species. Elevated abundances of crustal components (Al, Si, K, Ca, Fe) from geological material, carbon (OC, EC) and trace elements (Br, Pb) from vehicle exhausts, carbon (OC, EC) and ions (K(+), Cl(-)) from vegetative burning, ions (SO4(=), NH4(+), Na(+), K(+), Cl(-)) and elements (Cl, Se) from a manure-fueled power plants, and sulfur and trace elements (Na(+), Pb, Se, Ni, V) from an oil-fueled glass plant were found in the resulting source profiles. Abundances of crustal species (e.g. Al, Si, Ca) in the Imperial/Mexicali Valley geological profiles are more than twice those found in central and southern California. Abundances of lead in motor vehicle exhausts indicate different vehicle fleets in border cities. Emission profiles from field burning and charbroil cooking

  16. Recent geothermal developments in the Imperial Valley: Brawley, Salton Sea, Heber

    SciTech Connect

    Papay, L.T.

    1983-01-01

    Imperial Valley programs in geothermal energy are reviewed. The Brawley plant has had a relatively high availability on line since its startup in 1980. The startup at Salton Sea plant was surprisingly smooth. Using these research projects, all of the technical parameters for commercial development of geothermal energy will be known in a year or two. Native brine handling processes, casing materials and configurations, and turbine modifications are being studied. The PUC's decision on the Heber plant was a temporary setback. PUC ruled that projects will not be approved unless they yield competitive busbar costs. The Avoided Cost concept has become the benchmark at PUC. But Avoided Cost does not account for the higher initial design costs and unknown parameters of startup as opposed to mature plant costs. Avoided Cost is seen as the only obstacle to commercial developement in all areas.

  17. Response of El Centro Steam Plant equipment during the October 15, 1979 Imperial Valley earthquake

    SciTech Connect

    Nelson, T. A.; Murray, R. C.; Young, J. A.; Campbell, R. D.; Martore, J. A.; Levin, H. A.; Reiter, L.

    1980-09-01

    For the US Nuclear Regulatory Commission (NRC), Lawrence Livermore National Laboratory (LLNL) performed a dynamic seismic analysis of Unit 4 of the El Centro Steam Plant in El Centro, Calif. Built in 1968, Unit 4 is an oil- or gas-fired, steam-driven turbine-generator that was designed to resist a static lateral force equivalent to 20% of the dead and live load. The unit's structural and mechanical systems sustained only minor damage during the October 15, 1979 Imperial Valley earthquake that produced an estimated 0.5 g peak horizontal ground acceleration (0.66 g vertical) at the site. LLNL's seismic analysis was done to analytically estimate the equipment response, which, when compared to actual observation, will indicate the levels of actual equipment capacity. 15 refs., 51 figs., 11 tabs.

  18. Age and paleoenvironment of the imperial formation near San Gorgonio Pass, Southern California

    USGS Publications Warehouse

    McDougall, K.; Poore, R.Z.; Matti, J.

    1999-01-01

    Microfossiliferous marine sediments of the Imperial Formation exposed in the Whitewater and Cabazon areas, near San Gorgonio Pass, southern California, are late Miocene in age and were deposited at intertidal to outer neritic depths, and possibly upper bathyal depths. A late Miocene age of 7.4 to >6.04 Ma is based on the ranges of age-diagnostic benthic foraminifers (Cassidulina delicata and Uvigerina peregrina), planktic foraminifers (Globigerinoides obliquus, G. extremus, and Globigerina nepenthes; zones N17-N19), and calcareous nannoplankton (Discoaster brouweri, D. aff. D. surculus, Reticulofenestra pseudoumbilicata, Sphenolithus abies, and S. neoabies; zones CN9a-CN11) coupled with published K/Ar dates from the underlying Coachella Formation (10.1 ?? 1.2 Ma; Peterson, 1975) and overlying Painted Hill Formation (6.04 ?? 0.18 and 5.94 ?? 0.18 Ma; J. L. Morton in Matti and others, 1985 and Matti and Morton, 1993). Paleoecologic considerations (sea-level fluctuations and paleotemperature) restrict the age of the Imperial Formation to 6.5 through 6.3 Ma. Benthic foraminiferal assemblages indicate that the Imperial Formation in the Whitewater and Cabazon sections accumulated at inner neritic to outer neritic (0-152 m) and possibly upper bathyal (152-244 m) depths. Shallowing to inner neritic depths occurred as the upper part of the section was deposited. This sea-level fluctuation corresponds to a global highstand at 6.3 Ma (Haq and others, 1987). Planktic foraminifers suggest an increase in surface-water temperatures upsection. A similar increase in paleotemperatures is interpreted for the North Pacific from 6.5 to 6.3 Ma (warm interval W10 of Barron and Keller, 1983). Environmental contrasts between the Whitewater and Cabazon sections of the Imperial Formation provide evidence for right-lateral displacements on the Banning fault, a late Miocene strand of the San Andreas fault system. The Cabazon section lies south of the Banning fault, and has been displaced west

  19. Groundwater quality in the Antelope Valley, California

    USGS Publications Warehouse

    Dawson, Barbara J. Milby; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. Antelope Valley is one of the study areas being evaluated. The Antelope study area is approximately 1,600 square miles (4,144 square kilometers) and includes the Antelope Valley groundwater basin (California Department of Water Resources, 2003). Antelope Valley has an arid climate and is part of the Mojave Desert. Average annual rainfall is about 6 inches (15 centimeters). The study area has internal drainage, with runoff from the surrounding mountains draining towards dry lakebeds in the lower parts of the valley. Land use in the study area is approximately 68 percent (%) natural (mostly shrubland and grassland), 24% agricultural, and 8% urban. The primary crops are pasture and hay. The largest urban areas are the cities of Palmdale and Lancaster (2010 populations of 152,000 and 156,000, respectively). Groundwater in this basin is used for public and domestic water supply and for irrigation. The main water-bearing units are gravel, sand, silt, and clay derived from surrounding mountains. The primary aquifers in Antelope Valley are defined as those parts of the aquifers corresponding to the perforated intervals of wells listed in the California Department of Public Health database. Public-supply wells in Antelope Valley are completed to depths between 360 and 700 feet (110 to 213 meters), consist of solid casing from the land surface to a depth of 180 to 350 feet (55 to 107 meters), and are screened or perforated below the solid casing. Recharge to the groundwater system is primarily runoff from the surrounding mountains, and by direct infiltration of irrigation and sewer and septic

  20. Water Transfers, Air Quality, Ecosystems and Population Growth at the US-Mexico Border: An Integrated Model of the Mexicali and Imperial Valleys

    NASA Astrophysics Data System (ADS)

    Forster, C. B.; Gonzalez, T.; Peach, J.; Kjelland, M.; Collins, K.; Grant, W. E.

    2006-12-01

    Borderland communities in the Imperial-Mexicali Valleys (IMVs) of California (U.S.A.) and Mexicali (Mexico) are experiencing socioeconomic and environmental changes driven by policy makers and environmental conditions both within and outside the IMVs. The Colorado River Quantification Settlement Agreement (QSA) of 2003 will transfer 30 million acre-feet of Colorado River water from Imperial Valley (IV) agricultural users to Southern California urban users over a 75-year period. Because the water level of the Salton Sea is supported by agricultural runoff, reduced water flows to the sea raise concerns that: 1) air quality will be degraded as dust is generated by the drying Sea-bed, and 2) declining fish populations due to increasing salinity will no longer support birds migrating along a key avian flyway. Rapid population growth in the Mexican border-city of Mexicali, combined with new power plants and plans for water reuse, raises concerns that: 1) the quantity and quality of water supplied to the Salton Sea will decline, and 2) increased vehicle use and electrical power generation will lead to declining air quality in the binational air basin. Each concern may be affected by climate change. As environmental factors change, so too may the agricultural economy of the Imperial Valley that, in turn, depends on the availability of both water and manual labor. The economy of Mexicali is dominated by the maquiladora (manufacturing) industry that depends upon the availability of power, labor and water. A system dynamics model, with annual time step, simulates this complex binational system. The model was developed by an academic team with input from local experts/decision-makers from both Mexico and the US. We are preparing to engage community stakeholders and decision-makers in exploring the model. Insights gained from model results yield better understanding of the consequences of alternative future scenarios that include: QSA water transfers and land fallowing plans

  1. Slip on faults in the Imperial Valley Triggered by the 4 April 2010 Mw 7.2 El Major earthquake as revealed by InSAR

    NASA Astrophysics Data System (ADS)

    Wei, M.; Sandwell, D. T.; Fialko, Y.; Bilham, R. G.

    2010-12-01

    Radar interferometry (InSAR) reveals surface slip on multiple faults in the Imperial Valley triggered by the 2010 Baja M7.2 earthquake. Co-seismic offsets occurred on the San Andreas, Superstition Hills, Imperial, Elmore Ranch, Wienert, Coyote Creek, Elsinore, Yuha Wells, and several minor faults near the town of Ocotillo at the northern end of the mainshock rupture. We documented right-lateral slip (< 40 mm) on northwest trending faults and left-lateral slip (< 40 mm) on southwest trending faults. Slip occurred on 15-km- and 20-km-long segments of the San Andreas Fault in the Mecca Hills (≤ 50 mm) and Durmid Hill (≤ 10 mm) respectively, and 23 km of the Superstition Hills Fault (≤ 37 mm). Field measurements of slip on the Superstition Hills Fault agree with InSAR and creepmeter measurements to within a few millimeters. Dislocation models of the InSAR data on the Superstition Hills Fault confirm that creep in this sequence, as in previous slip events, is confined to shallow depths (< 3 km). Map of Southern California and Northern Baja California. Black solid lines are major faults. Yellow solid lines are faults with observed offsets. Dashed black lines are National and State borders. White star is the epicenter of the 2010 April 4th El Major earthquake. Red dots are aftershocks within one month after the main rupture with magnitude greater than 5, blue 4-5, and green 3-4. Earthquake data are from the Southern California Earthquake Center. Fault names are abbreviated as follows: ERF, Elmore Ranch fault; SHF, Superstition Hills fault; SMF, Superstition Mountains fault; WF, Wienert fault; YWF, Yuha Wells Fault.

  2. The Salton Seismic Imaging Project: Tomographic characterization of a sediment-filled rift valley and adjacent ranges, southern California

    NASA Astrophysics Data System (ADS)

    Davenport, K.; Hole, J. A.; Stock, J. M.; Fuis, G. S.; Carrick, E.; Tikoff, B.

    2011-12-01

    The Salton Trough in Southern California represents the northernmost rift of the Gulf of California extensional system. Relative motion between the Pacific and North American plates is accommodated by continental rifting in step-over zones between the San Andreas, Imperial, and Cerro Prieto transform faults. Rapid sedimentation from the Colorado River has isolated the trough from the southern portion of the Gulf of California, progressively filling the subsiding rift basin. Based on data from previous seismic surveys, the pre-existing continent has ruptured completely, and a new ~22 km thick crust has been created entirely by sedimentation overlying rift-related magmatism. The MARGINS, EarthScope, and USGS-funded Salton Seismic Imaging Project (SSIP) was designed to investigate the nature of this new crust, the ongoing process of continental rifting, and associated earthquake hazards. SSIP, acquired in March 2011, comprises 7 lines of onshore seismic refraction / wide-angle reflection data, 2 lines of refraction / reflection data in the Salton Sea, and a line of broadband stations. This presentation focuses on the refraction / wide-angle reflection line across the Imperial Valley, extending ~220 km across California from Otay Mesa, near Tijuana, to the Colorado River. The data from this line includes seventeen 100-160 kg explosive shots and receivers at 100 m spacing across the Imperial Valley to constrain the structure of the Salton Trough rift basin, including the Imperial Fault. Eight larger shots (600-920 kg) at 20-35 km spacing and receivers at 200-500 m spacing extend the line across the Peninsular Ranges and the Chocolate Mountains. These data will contrast the structure of the rift to that of the surrounding crust and provide constraints on whole-crust and uppermost mantle structure. Preliminary work has included tomographic inversion of first-arrival travel times across the Valley, emphasizing a minimum-structure approach to create a velocity model of the

  3. Death Valley California as seen from STS-59

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This oblique handheld Hasselblad 70mm photo shows Death Valley, near California's border with Nevada. The valley -- the central feature of Death Valley National Monument -- extends north to south for some 140 miles (225 kilometers). Hemmed in to the east by the Amargosa Range and to the west by the Panamints, its width varies from 5 to 15 miles (8 to 24 kilometers).

  4. Space Radar Image of Saline Valley, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a three-dimensional perspective view of Saline Valley, about 30 km (19 miles) east of the town of Independence, California created by combining two spaceborne radar images using a technique known as interferometry. Visualizations like this one are helpful to scientists because they clarify the relationships of the different types of surfaces detected by the radar and the shapes of the topographic features such as mountains and valleys. The view is looking southwest across Saline Valley. The high peaks in the background are the Inyo Mountains, which rise more than 3,000 meters (10,000 feet) above the valley floor. The dark blue patch near the center of the image is an area of sand dunes. The brighter patches to the left of the dunes are the dry, salty lake beds of Saline Valley. The brown and orange areas are deposits of boulders, gravel and sand known as alluvial fans. The image was constructed by overlaying a color composite radar image on top of a digital elevation map. The radar image was taken by the Spaceborne Imaging Radar-C/X-bandSynthetic Aperture Radar (SIR-C/X-SAR) on board the space shuttleEndeavour in October 1994. The digital elevation map was producedusing radar interferometry, a process in which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The elevation data were derived from a 1,500-km-long (930-mile) digital topographic map processed at JPL. Radar image data are draped over the topography to provide the color with the following assignments: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vetically received; and blue is the ratio of C-band vertically transmitted, vertically received to L-band vertically transmitted, vertically received. This image is centered near 36.8 degrees north latitude and 117.7 degrees west longitude. No vertical exaggeration factor has been applied to the data. SIR-C/X-SAR, a joint

  5. Space Radar Image of Death Valley, California

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This image shows Death Valley, California, centered at 36.629 degrees north latitude, 117.069 degrees west longitude. The image shows Furnace Creek alluvial fan and Furnace Creek Ranch at the far right, and the sand dunes near Stove Pipe Wells at the center. The dark fork-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. This SIR-C/X-SAR supersite is an area of extensive field investigations and has been visited by both Space Radar Lab astronaut crews. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using SIR-C/X-SAR data from Death Valley to help answer a number of different questions about Earth's geology. One question concerns how alluvial fans are formed and change through time under the influence of climatic changes and earthquakes. Alluvial fans are gravel deposits that wash down from the mountains over time. They are visible in the image as circular, fan-shaped bright areas extending into the darker valley floor from the mountains. Information about the alluvial fans helps scientists study Earth's ancient climate. Scientists know the fans are built up through climatic and tectonic processes and they will use the SIR-C/X-SAR data to understand the nature and rates of weathering processes on the fans, soil formation and the transport of sand and dust by the wind. SIR-C/X-SAR's sensitivity to centimeter-scale (inch-scale) roughness provides detailed maps of surface texture. Such information can be used to study the occurrence and movement of dust storms and sand dunes. The goal of these studies is to gain a better understanding of the record of past climatic changes and the effects of those changes on a sensitive environment. This may lead to a better ability to predict future response of the land to different potential global climate-change scenarios. Death Valley is

  6. ANALYSIS OF LOTIC MACROINVERTEBRATE ASSEMBLAGES IN CALIFORNIA'S CENTRAL VALLEY

    EPA Science Inventory

    Using multivariate and cluster analyses, we examined the relaitonships between chemical and physical characteristics and macroinvertebrate assemblages at sites sampled by R-EMAP in California's Central Valley. By contrasting results where community structure was summarized as met...

  7. 76 FR 67369 - Revisions to the California State Implementation Plan, Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-01

    ... Pollution Control District and Imperial County Air Pollution Control District AGENCY: Environmental... Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) and Imperial County Air Pollution Control.... Proposed Action On June 3, 2011 (FR 32113), EPA proposed to approve the following rules into the...

  8. Water supply issues of the San Joaquin Valley in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The San Joaquin Valley of California is undoubtedly one of the most productive agricultural regions of the United States, and of the world. The valley was a Miocene epicontinental sea bounded by the Sierra Nevada igneous arc in the east and the Coast Range accretionary terrane in the west. It is now...

  9. space Radar Image of Long Valley, California

    NASA Technical Reports Server (NTRS)

    1994-01-01

    An area near Long Valley, California, was mapped by the Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar aboard the space shuttle Endeavor on April 13, 1994, during the first flight of the radar instrument, and on October 4, 1994, during the second flight of the radar instrument. The orbital configurations of the two data sets were ideal for interferometric combination -- that is overlaying the data from one image onto a second image of the same area to create an elevation map and obtain estimates of topography. Once the topography is known, any radar-induced distortions can be removed and the radar data can be geometrically projected directly onto a standard map grid for use in a geographical information system. The 50 kilometer by 50 kilometer (31 miles by 31 miles) map shown here is entirely derived from SIR-C L-band radar (horizontally transmitted and received) results. The color shown in this image is produced from the interferometrically determined elevations, while the brightness is determined by the radar backscatter. The map is in Universal Transverse Mercator (UTM) coordinates. Elevation contour lines are shown every 50 meters (164 feet). Crowley Lake is the dark feature near the south edge of the map. The Adobe Valley in the north and the Long Valley in the south are separated by the Glass Mountain Ridge, which runs through the center of the image. The height accuracy of the interferometrically derived digital elevation model is estimated to be 20 meters (66 feet) in this image. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global

  10. Arc-rift transition volcanism in the Volcanic Hills, Jacumba and Coyote Mountains, San Diego and Imperial Counties, california

    NASA Astrophysics Data System (ADS)

    Fisch, Gregory Zane

    Neogene volcanism associated with the subduction of the Farallon-Pacific spreading center and the transition from a subduction zone to a rift zone has been studied extensively in Baja, California, Mexico. One of the main goals of these studies was to find a geochemical correlation with slab windows that may have formed during that complicated transition. While workers have been able to find distinct geochemical signatures in samples from Baja California, none have shown statistically significant correlation with samples from southern California that are thought to be related to the same arc-rift transition events. All of the basaltic samples from this study of southern California rocks have prominent Nb depletions typical of island-arc subduction-related volcanism, in contrast to the chemistry of Baja California volcanics that have trace element patterns typical of synrift related volcanism. The work done by previous investigators has been additionally complicated due to each investigator's choice of important ratios or patterns, which bears little, if any, correlation with work done by others working in the same area. For example, Martin-Barajas et al. (1995) use K/Rb ratios in their study of the Puertocitos Volcanic Province, while Castillo (2008) argues that Sr/Y vs. Y is a better indicator of petrogenetic processes. Little petrologic work has been done on Neogene volcanic rocks in the Imperial Valley and eastern San Diego County region of Southern California. This thesis combines new research with that of previous workers and attempts to establish a better understanding of the processes involved with the transition volcanism. Prior work documents significant differences in the geochemistry between some of these areas, especially those in close proximity to each other (e.g. the Volcanic Hills and Coyote Mountains). These differences were thought to be largely the result different magmatic sources. The potential of finding two differing magma types in close

  11. 3D View of Death Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This 3-D perspective view looking north over Death Valley, California, was produced by draping ASTER nighttime thermal infrared data over topographic data from the US Geological Survey. The ASTER data were acquired April 7, 2000 with the multi-spectral thermal infrared channels, and cover an area of 60 by 80 km (37 by 50 miles). Bands 13, 12, and 10 are displayed in red, green and blue respectively. The data have been computer enhanced to exaggerate the color variations that highlight differences in types of surface materials. Salt deposits on the floor of Death Valley appear in shades of yellow, green, purple, and pink, indicating presence of carbonate, sulfate, and chloride minerals. The Panamint Mtns. to the west, and the Black Mtns. to the east, are made up of sedimentary limestones, sandstones, shales, and metamorphic rocks. The bright red areas are dominated by the mineral quartz, such as is found in sandstones; green areas are limestones. In the lower center part of the image is Badwater, the lowest point in North America.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.

    The broad spectral coverage and high spectral resolution of ASTER

  12. Niland development project geothermal loan guaranty: 49-MW (net) power plant and geothermal well field development, Imperial County, California: Environmental assessment

    SciTech Connect

    Not Available

    1984-10-01

    The proposed federal action addressed by this environmental assessment is the authorization of disbursements under a loan guaranteed by the US Department of Energy for the Niland Geothermal Energy Program. The disbursements will partially finance the development of a geothermal well field in the Imperial Valley of California to supply a 25-MW(e) (net) power plant. Phase I of the project is the production of 25 MW(e) (net) of power; the full rate of 49 MW (net) would be achieved during Phase II. The project is located on approximately 1600 acres (648 ha) near the city of Niland in Imperial County, California. Well field development includes the initial drilling of 8 production wells for Phase I, 8 production wells for Phase II, and the possible need for as many as 16 replacement wells over the anticipated 30-year life of the facility. Activities associated with the power plant in addition to operation are excavation and construction of the facility and associated systems (such as cooling towers). Significant environmental impacts, as defined in Council on Environmental Quality regulation 40 CFR Part 1508.27, are not expected to occur as a result of this project. Minor impacts could include the following: local degradation of ambient air quality due to particulate and/or hydrogen sulfide emissions, temporarily increased ambient noise levels due to drilling and construction activities, and increased traffic. Impacts could be significant in the event of a major spill of geothermal fluid, which could contaminate groundwater and surface waters and alter or eliminate nearby habitat. Careful land use planning and engineering design, implementation of mitigation measures for pollution control, and design and implementation of an environmental monitoring program that can provide an early indication of potential problems should ensure that impacts, except for certain accidents, will be minimized.

  13. Public health assessment for Stoker Company, Imperial, Imperial County, California, Region 9. Cerclis No. CAD066635442. Preliminary report

    SciTech Connect

    Not Available

    1994-01-06

    Stoker Company is a pesticide dealer and crop dusting loading facility located in the County of Imperial, approximately 25 miles from the Mexican border. The 26-acre site is barren with no vegetation. Operations at the facility, beginning in 1966, have caused the surface soil over much of the site to be contaminated with pesticides. Some of the contaminated surface soil has blown off-site and impacted nearby surface soil and surface water. This preliminary public health assessment evaluated the potential for adverse health effects to occur in five populations identified as being impacted by contaminants. The impacted populations include: (1) on-site workers; (2) the family formerly living on the neighboring D K property; (3) the D K Duck Hunting Club members; (4) individuals using untreated surface water for drinking and/or other domestic purposes; and (5) individuals living or working near crop dusting operations. Based on this assessment, Stoker Company is considered to pose a public health hazard because long-term exposure to site-related contaminants may cause adverse health effects.

  14. Perspective with Landsat Overlay: Antelope Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Antelope Valley is bounded by two of the most active faults in California: the Garlock fault, which fronts the distant mountains in this view, and the San Andreas fault, part of which is seen bounding the mountains in the left foreground. In this view, Antelope Valley is in the foreground, the Tehachapi Mountains form the left skyline, and ranges within the southernmost Sierra Nevada form the right skyline. Antelope Valley is directly north of Los Angeles and is the westernmost part of the Mojave Desert. It is a closed basin. Stream flow here ends at Rosamond and Rogers dry lakes, which appear bright white. Dry lakes like these are common where tectonic activity raises and lowers parts of the Earth's crust, and thus the topographic surface, faster than stream flow can fill depressions with water, and then overflow and cut escape channels to other basins and eventually to the sea. The Sierra Nevada, the Tehachapi, and other mountains generally to the west create a rain shadow desert here. Thus, the area definitely has the active tectonics and low rainfall combination that leads to closed basin topography.

    This perspective view was generated by draping a Landsat satellite image over a preliminary topographic map from the Shuttle Radar Topography Mission. Shading of the SRTM elevation model was added to enhance topographic appearance. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30 meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive.

    The elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three

  15. 75 FR 27975 - Revisions to the California State Implementation Plan; Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ...: EPA is proposing to approve revisions to the Imperial County Air Pollution Control District (ICAPCD... previous version of Rule 420 (see 68 FR 8839). CARB has made no subsequent submittals of the rule. C. What..., Imperial County was reclassified as a serious PM nonattainment area (see 69 FR 48792 and 40 CFR part...

  16. Deformation near the Coyote Creek fault, Imperial County, California: Tectonic or groundwater-related?

    NASA Astrophysics Data System (ADS)

    Mellors, Robert J.; Boisvert, Alex

    2003-02-01

    Interferometric synthetic aperture radar (InSAR) measurements show a consistent, 40-km2 wedge-shaped area of deformation partially bounded by a branch of the Coyote Creek fault (a southern extension of the San Jacinto fault) in Imperial County, California, west of the Salton Sea. The deformation is centered at 33.1 N latitude, 116.0 W longitude. 18 ERS-1 and ERS-2 (descending) interferograms falling within 1992 to 2000 are analyzed. An average line-of-sight range change over the area of 6 ± 3 mm per year away from the satellite is observed with peak values up to 12 ± 3 mm per year. The southwestern edge of the deformation is partially bounded by a fault segment that ruptured in the 1968 Mw 6.5 Borrego Mountain earthquake and which also showed triggered slip after the 1987 Superstition Hills earthquakes. The southeastern edge of the deformation also coincides with a mapped fault. The deformation is centered on a farming area that has pumped approximately 5.8 × 10-6 m3 per year of groundwater from 5 wells on the property and which shows declining water levels of 1.4 m per year. The area of highest change appears to be centered on location of the wells and away from the faults. The aquifer is at a depth of roughly 100 to 200 m and consists of sands with interbedded clays. It appears that the most likely explanation is subsidence due to groundwater withdrawal in a fault-bounded aquifer rather than tectonic slip.

  17. Magma energy exploratory well Long Valley caldera, Mono County, California

    SciTech Connect

    Bender-Lamb, S.

    1991-04-01

    Intensive study of Long Valley over the past 15 years indicates evidence for magma at depths accessible to drilling. The Department of Energy's Magma Energy Extraction Program is currently drilling a 20,000 foot exploratory well into the Long Valley caldera. The purpose of this program is to determine the feasibility of producing electrical power from magma. If the magma energy experiment is successful, the Long Valley caldera could hypothetically supply the electrical power needs of California for 100 years at present power consumption rates. The paper describes calderas, the potential of geothermal energy, Long Valley geology, the Long Valley magma energy exploratory well, the four phases of the exploratory well drilling program, and Phase 1 results.

  18. Precipitation depth-duration characteristics, Antelope Valley, California

    USGS Publications Warehouse

    Blodgett, James C.; Nasseri, Iraj

    1995-01-01

    To document the changes in runoff characteristics of basins subject to urbanization, streamflow and precipitation data were collected at eight small basins in Antelope Valley, California, for the period 1990-93. The data collected at U.S. Geological Survey stations were supplemented by data collected at 35 long-term precipitation stations. These data will be used to calibrate and verify rainfall-runoff models for the eight basins and for estimating basin runoff characteristics throughout Antelope Valley. Annual precipitation in Antelope Valley varies from more than 50 cm in the mountains to less than 10 cm on the valley floor. Most precipitation in the valley occurs during the winter months, December through March, but cyclonic storms in the fall and convectional storms in the summer sometimes occur.

  19. Surface displacement on the Imperial and Superstition Hills faults triggered by the Westmorland, California, earthquake of 26 April 1981

    USGS Publications Warehouse

    Sharp, R.V.; Lienkaemper, J.J.; Rymer, M.J.

    1982-01-01

    Parts of the Imperial and the Superstition Hills faults moved right-laterally at the ground surface at the time of or shortly following the ML 5.6 Westmorland earthquake of 26 April 1981. The displacements occurred prior to any significant aftershocks on either fault and thus are classed as sympathetic. Although the main shock was located in an exceptionally seismogenic part of Imperial Valley, about 20 km distant from either fault, no clear evidence of surface faulting has yet been found in the epicentral area. Horizontal displacement on the Imperial and Superstition Hills faults, southeast and southwest of the epicenter, respectively, reached maxima of 8 mm and 14 mm, and the discontinuous surface ruptures formed along approximately equal lengths of northern segments of the two structures (16.8 km and 15.7 km, respectively). The maximum vertical component of slip on the Imperial fault, 6 ram, was observed 3.4 km north of the point of largest horizontal slip. Vertical movement on the Superstition Hills fault was less than 1 mm. No new displacement was found along the traces of the Brawley fault zone, the San Andreas fault, or the part of the Coyote Creek fault that slipped during the 1968 Borrego Mountain earthquake. A careful search in the epicentral area of the main shock failed to locate any definite evidence of surface faulting. Concentrations of late aftershocks north and northeast of Calipatria near the southeastward projection of the San Andreas fault occurred mostly after our field check; this area was not investigated.

  20. California's Central Valley Groundwater Study: A Powerful New Tool to Assess Water Resources in California's Central Valley

    USGS Publications Warehouse

    Faunt, Claudia C.; Hanson, Randall T.; Belitz, Kenneth; Rogers, Laurel

    2009-01-01

    Competition for water resources is growing throughout California, particularly in the Central Valley. Since 1980, the Central Valley's population has nearly doubled to 3.8 million people. It is expected to increase to 6 million by 2020. Statewide population growth, anticipated reductions in Colorado River water deliveries, drought, and the ecological crisis in the Sacramento-San Joaquin Delta have created an intense demand for water. Tools and information can be used to help manage the Central Valley aquifer system, an important State and national resource.

  1. Apricot variety development in California's San Joaquin Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercial apricot production began in California's mild coastal valleys during the early part of the 20th century. Varieties such as 'Blenheim,' 'Derby,' 'Hemskirke,' 'Moorpark,''Newcastle,''Steward,''Tilton' and 'Wiggins' were all cultivated commercially throughout the growing regions for fresh m...

  2. Likelihood of volcanic eruption at Long Valley, California, is reduced

    USGS Publications Warehouse

    Kelly, D.

    1984-01-01

    A relatively low level of earthquake activity as well as reduced rates of ground deformation over the past year have led U.S Geological Survey scientists to conclude that the likelihood of imminent volcanic activity at Long Valley, California, is reduced from that of mid-1982 through 1983.

  3. Status of groundwater pollution in the San Gabriel Valley, California

    SciTech Connect

    Earley, J.D.

    1987-07-01

    Contamination of groundwater in the San Gabriel Valley of California has been identified as a potential health hazard from industrial sources. Sampling has revealed the presence of trichloroethylene (TCE), perchloroethylene (PCE) and carbon tetrachloride (CTC); therefore, water purveyors are using a variety of means to alleviate the contamination and the use of contaminated water.

  4. Final Scientific / Technical Report, Geothermal Resource Exploration Program, Truckhaven Area, Imperial County, California

    SciTech Connect

    Layman Energy Associates, Inc.

    2006-08-15

    With financial support from the U.S. Department of Energy (DOE), Layman Energy Associates, Inc. (LEA) has completed a program of geothermal exploration at the Truckhaven area in Imperial County, California. The exploratory work conducted by LEA included the following activities: compilation of public domain resource data (wells, seismic data, geologic maps); detailed field geologic mapping at the project site; acquisition and interpretation of remote sensing imagery such as aerial and satellite photographs; acquisition, quality control and interpretation of gravity data; and acquisition, quality control and interpretation of resistivity data using state of the art magnetotelluric (MT) methods. The results of this exploratory program have allowed LEA to develop a structural and hydrologic interpretation of the Truckhaven geothermal resource which can be used to guide subsequent exploratory drilling and resource development. Of primary significance, is the identification of an 8 kilometer-long, WNW-trending zone of low resistivity associated with geothermal activity in nearby wells. The long axis of this low resistivity zone is inferred to mark a zone of faulting which likely provides the primary control on the distribution of geothermal resources in the Truckhaven area. Abundant cross-faults cutting the main WNW-trending zone in its western half may indicate elevated fracture permeability in this region, possibly associated with thermal upwelling and higher resource temperatures. Regional groundwater flow is inferred to push thermal fluids from west to east along the trend of the main low resistivity zone, with resource temperatures likely declining from west to east away from the inferred upwelling zone. Resistivity mapping and well data have also shown that within the WNW-trending low resistivity zone, the thickness of the Plio-Pleistocene sedimentary section above granite basement ranges from 1,900–2,600 meters. Well data indicates the lower part of this

  5. Aeromagnetic survey map of Sacramento Valley, California

    USGS Publications Warehouse

    Langenheim, Victoria E.

    2015-01-01

    Three aeromagnetic surveys were flown to improve understanding of the geology and structure in the Sacramento Valley. The resulting data serve as a basis for geophysical interpretations, and support geological mapping, water and mineral resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals commonly mark lithologic or structural boundaries. Bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense positive magnetic anomalies (for example, in the northwest part of the map). These rock types are the inferred sources, concealed beneath weakly magnetic, valley-fill deposits, of the most prominent magnetic features in the map area, the magnetic highs that extend along the valley axis. Cenozoic volcanic rocks are also an important source of magnetic anomalies and coincide with short-wavelength anomalies that can be either positive (strong central positive anomaly flanked by lower-amplitude negative anomalies) or negative (strong central negative anomaly flanked by lower-amplitude positive anomalies), reflecting the contribution of remanent magnetization. Rocks with more felsic compositions or even some sedimentary units also can cause measurable magnetic anomalies. For example, the long, linear, narrow north-trending anomalies (with amplitudes of <50 nanoteslas [nT]) along the western margin of the valley coincide with exposures of the Mesozoic Great Valley sequence. Note that isolated, short-wavelength anomalies, such as those in the city of Sacramento and along some of the major roads, are caused by manmade features.

  6. Sutter Buttes-the lone volcano in California's Great Valley

    USGS Publications Warehouse

    Hausback, Brain P.; Muffler, L.J. Patrick; Clynne, Michael A.

    2011-01-01

    The volcanic spires of the Sutter Buttes tower 2,000 feet above the farms and fields of California's Great Valley, just 50 miles north-northwest of Sacramento and 11 miles northwest of Yuba City. The only volcano within the valley, the Buttes consist of a central core of volcanic domes surrounded by a large apron of fragmental volcanic debris. Eruptions at the Sutter Buttes occurred in early Pleistocene time, 1.6 to 1.4 million years ago. The Sutter Buttes are not part of the Cascade Range of volcanoes to the north, but instead are related to the volcanoes in the Coast Ranges to the west in the vicinity of Clear Lake, Napa Valley, and Sonoma Valley.

  7. The Obsidian Creep Project: Seismic Imaging in the Brawley Seismic Zone and Salton Sea Geothermal Field, Imperial County, California

    NASA Astrophysics Data System (ADS)

    Catchings, R. D.; Rymer, M. J.; Goldman, M.; Lohman, R. B.; McGuire, J. J.

    2010-12-01

    In March 2010, we acquired medium- and high-resolution P- and S-wave seismic reflection and refraction data across faults in the Brawley seismic zone (BSZ) and across part of the Salton Sea Geothermal Field (SSGF), Imperial Valley, California. Our objectives were to determine the dip, possible structural complexities, and seismic velocities associated with the BSZ and SSGF. We acquired multiple seismic data sets along a north-south profile and a high-resolution P-wave profile along an east-west profile. The north-south profile included: 1) a 6.4-km-long P-wave (main) profile that was recorded on 320 Texan seismographs spaced at 20-m intervals, 2) a 1.2-km-long cabled, high-resolution profile along the northern end of the main profile, and 3) an approximately 1.2-km-long S-wave profile along the cabled profile. P-wave sources along the main profile were generated by 0.15- to 0.45-kg buried explosions spaced every 40 m, and P-wave sources along the cabled profile were generated by Betsy-Seisgun ‘shots’ spaced every 10 m. S-waves sources were generated by hammer impacts on the ends of an aluminum block. The east-west profile consisted of a 3.4-km-long high-resolution P-wave seismic profile with shots (Betsy-Seisgun) and geophones spaced every 10 m. Preliminary interpretation of shot gathers from blasts in the north-south profile suggests that the BSZ and SSGF are structurally complex, with abundant faults extending to or near the ground surface. Also, we observe relatively high-velocity material, apparent velocities of about 4.0 km/s in one direction and about 2.8 km/s in another relative to about 1.6 km/s for shallower material, that shallows beneath the SSGF. This may be due to high temperatures and resultant metamorphism of buried materials in the SSGF. From preliminary interpretation of shot gathers along the east-west profile we interpret a prominent fault that extends to the ground surface. This fault is on projection of the Kalin fault, from about 40 m to

  8. Arc-rift transition volcanism in the Volcanic Hills, Jacumba and Coyote Mountains, San Diego and Imperial Counties, california

    NASA Astrophysics Data System (ADS)

    Fisch, Gregory Zane

    Neogene volcanism associated with the subduction of the Farallon-Pacific spreading center and the transition from a subduction zone to a rift zone has been studied extensively in Baja, California, Mexico. One of the main goals of these studies was to find a geochemical correlation with slab windows that may have formed during that complicated transition. While workers have been able to find distinct geochemical signatures in samples from Baja California, none have shown statistically significant correlation with samples from southern California that are thought to be related to the same arc-rift transition events. All of the basaltic samples from this study of southern California rocks have prominent Nb depletions typical of island-arc subduction-related volcanism, in contrast to the chemistry of Baja California volcanics that have trace element patterns typical of synrift related volcanism. The work done by previous investigators has been additionally complicated due to each investigator's choice of important ratios or patterns, which bears little, if any, correlation with work done by others working in the same area. For example, Martin-Barajas et al. (1995) use K/Rb ratios in their study of the Puertocitos Volcanic Province, while Castillo (2008) argues that Sr/Y vs. Y is a better indicator of petrogenetic processes. Little petrologic work has been done on Neogene volcanic rocks in the Imperial Valley and eastern San Diego County region of Southern California. This thesis combines new research with that of previous workers and attempts to establish a better understanding of the processes involved with the transition volcanism. Prior work documents significant differences in the geochemistry between some of these areas, especially those in close proximity to each other (e.g. the Volcanic Hills and Coyote Mountains). These differences were thought to be largely the result different magmatic sources. The potential of finding two differing magma types in close

  9. Beginnings of geothermal impact on county population and leadership, Imperial County, California

    SciTech Connect

    Pick, J.B.; Butler, E.W.

    1980-09-01

    A major geothermal energy development scenario is about to begin in Imperial County. Initial energy-socioeconomic interactions in the areas of population and county leadership structure are discussed. These include immigration of energy company workers, a sewage plant dispute, conflict over union affiliation of geothermal laborers, and a transmission corridor routing dispute.

  10. 78 FR 896 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-07

    ... is finalizing approval of revisions to the Imperial County Air Pollution Control District (ICAPCD... IV. Statutory and Executive Order Reviews I. Proposed Action On April 27, 2012 (77 FR 25109), EPA... and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993); does not impose an...

  11. 78 FR 23677 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ... is finalizing approval of revisions to the Imperial County Air Pollution Control District (ICAPCD... III. EPA Action IV. Statutory and Executive Order Reviews I. Proposed Action On January 7, 2013 (78 FR... not acting on Rule 802 at this time. \\2\\ See, e.g., 75 FR 8010 (February 23, 2010). Comment...

  12. 76 FR 39303 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... Pollution Control District, Kern County Air Pollution Control District, and Ventura County Air Pollution... taking direct final action to approve revisions to the Imperial County Air Pollution Control District (ICAPCD), Kern County Air Pollution Control District (KCAPCD), and Ventura County Air Pollution...

  13. 76 FR 7142 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-09

    ...: EPA is proposing to approve revisions to the Imperial County Air Pollution Control District (ICAPCD... versions of these rules? We approved an earlier version of Rule 201 into the SIP on January 3, 2007 (72 FR... permit exemptions. Rule 103 was approved into the SIP on May 31, 1972 (37 FR 10842). The...

  14. 77 FR 25109 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-27

    ... Implementation of Title I of the Clean Air Act Amendments of 1990,'' 59 FR 41998 (August 16, 1994). 5. ``PM-10...: EPA is proposing to approve revisions to the Imperial County Air Pollution Control District (ICAPCD...-2008 monitoring period (74 FR 63309). This determination suspended some of the planning...

  15. 76 FR 39357 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-06

    ... Pollution Control District, Kern County Air Pollution Control District, and Ventura County Air Pollution... proposing to approve revisions to the Imperial County Air Pollution Control District (ICAPCD), Kern County Air Pollution Control District (KCAPCD), and Ventura County Air Pollution Control District...

  16. 78 FR 922 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-07

    ... for the Implementation of Title I of the Clean Air Act Amendments of 1990,'' 57 FR 13498 (April 16... Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990,'' 59 FR 41998 (August...: EPA is proposing to approve revisions to the Imperial County Air Pollution Control District...

  17. 75 FR 39365 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-08

    ... minimis level. Id. at 42011. \\19\\ 75 FR 8008, 8010, and proposal TSD, pp. 5-7. Open areas: --Windblown... Order Reviews I. Summary of Proposed Action On February 23, 2010 (75 FR 8008), EPA proposed a limited... section E.6 for recreational use of public lands in Imperial County. \\6\\ 75 FR 8008, 8010-8011 and...

  18. Mineral deficiencies in tule elk, Owens Valley, California.

    PubMed

    Johnson, Heather E; Bleich, Vernon C; Krausman, Paul R

    2007-01-01

    Male tule elk (Cervus elaphus nannodes) are susceptible to high rates of antler breakage in Owens Valley, California. We hypothesized that a mineral deficiency in the diet predisposed male elk to antler breakage. We analyzed elk antler, liver, and forage samples to identify mineral imbalances. We compared the mineral content of livers and antlers from elk in Owens Valley to samples taken from tule elk at Grizzly Island Wildlife Area, a population experiencing normal rates (<5%) of antler breakage. Antler and liver samples were collected from 1989 to 1993, and in 2002, and were tested for calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), phosphorus (P), sulfur (S), and zinc (Zn). Mineral levels from antler and liver samples were compared to reference values established for elk and deer. We also compared the mineral content of elk forage in Owens Valley, collected in 2002-03, to dietary reference values established for cattle. In antlers, Ca, Fe, and Mg levels were higher in Owens Valley elk than in Grizzly Island elk, although all mineral levels were lower than reference values established for deer antlers. In liver samples, Cu levels from elk in Owens Valley were lower than those from Grizzly Island and lower than minimum reference values; liver Ca and Mo levels were higher in elk from Owens Valley than in those from Grizzly Island. Compared to reference values, elk forage in Owens Valley had high levels of Ca and Mo, and low levels of Cu, P, and Zn. Mineral analyses from antlers, livers, and forage suggest that tule elk in the Owens Valley are Cu and/or P deficient. High levels of Mo and Ca may exacerbate Cu and P deficiencies, respectively. Bone fragility is a symptom of both deficiencies, and an imbalance in Cu, P, or a combination of both, may predispose male tule elk in the Owens Valley to antler breakage. PMID:17347394

  19. Climate controls on valley fever incidence in Kern County, California

    NASA Astrophysics Data System (ADS)

    Zender, Charles S.; Talamantes, Jorge

    2006-01-01

    Coccidiodomycosis (valley fever) is a systemic infection caused by inhalation of airborne spores from Coccidioides immitis, a soil-dwelling fungus found in the southwestern United States, parts of Mexico, and Central and South America. Dust storms help disperse C. immitis so risk factors for valley fever include conditions favorable for fungal growth (moist, warm soil) and for aeolian soil erosion (dry soil and strong winds). Here, we analyze and inter-compare the seasonal and inter-annual behavior of valley fever incidence and climate risk factors for the period 1980-2002 in Kern County, California, the US county with highest reported incidence. We find weak but statistically significant links between disease incidence and antecedent climate conditions. Precipitation anomalies 8 and 20 months antecedent explain only up to 4% of monthly variability in subsequent valley fever incidence during the 23 year period tested. This is consistent with previous studies suggesting that C. immitis tolerates hot, dry periods better than competing soil organisms and, as a result, thrives during wet periods following droughts. Furthermore, the relatively small correlation with climate suggests that the causes of valley fever in Kern County could be largely anthropogenic. Seasonal climate predictors of valley fever in Kern County are similar to, but much weaker than, those in Arizona, where previous studies find precipitation explains up to 75% of incidence. Causes for this discrepancy are not yet understood. Higher resolution temporal and spatial monitoring of soil conditions could improve our understanding of climatic antecedents of severe epidemics.

  20. Preliminary subsidence investigation of Sacramento Valley, California

    USGS Publications Warehouse

    Lofgren, B.E.; Ireland, R.L.

    1973-01-01

    Although a number of agencies have made leveling surveys in Sacramento Valley and a valleywide network of first- and second-order control exists, few areas have sufficient control for determining whether land subsidence has occurred and if so, how much, within the time span of vertical control. Available data suggest that 0.2 to 0.9 foot (0.06 to 0.3 m) of subsidence probably has occurred from 1935-42 to 1964 in an extensive agricultural area of heavy ground-water pumping between Zamora and Davis, and that as much as 2 feet (0.6 m) of subsidence has occurred in at least two areas of pumping overdraft--east of Zamora, and west of Arbuckle. A comparison of maps showing long-term water-level decline and average annual ground-water pumpage indicates several other areas of probable subsidence. In six general areas--northwest of Sacramento; northeast of Sacramento; southeast of Yuba City; 10 miles (16 km) north of Willows; 20 miles (32 km) north of Willows; and especially in the Arbuckle area,ground-water declines have quite probably produced significant subsidence. In two areas of most intensive pumping, no long-term water-level declines have occurred, and no subsidence is indicated. If problems of land subsidence are of concern in Sacramento Valley, and if estimates of historic subsidence or subsidence potential are needed, serious consideration should be given to a field program of basic-data collection. Second-order leveling along a few carefully selected lines of existing control, and the installation and operation of two or three compaction recorders in areas of continuing water-level decline, would provide helpful data for estimating .past and future subsidence.

  1. 27 CFR 9.219 - Antelope Valley of the California High Desert.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... California High Desert. 9.219 Section 9.219 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX... Viticultural Areas § 9.219 Antelope Valley of the California High Desert. (a) Name. The name of the viticultural area described in this section is “Antelope Valley of the California High Desert”. For purposes...

  2. 27 CFR 9.219 - Antelope Valley of the California High Desert.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... California High Desert. 9.219 Section 9.219 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX... Viticultural Areas § 9.219 Antelope Valley of the California High Desert. (a) Name. The name of the viticultural area described in this section is “Antelope Valley of the California High Desert”. For purposes...

  3. 27 CFR 9.219 - Antelope Valley of the California High Desert.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... California High Desert. 9.219 Section 9.219 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX... Viticultural Areas § 9.219 Antelope Valley of the California High Desert. (a) Name. The name of the viticultural area described in this section is “Antelope Valley of the California High Desert”. For purposes...

  4. Microscopic Identification of Prokaryotes in Modern and Ancient Halite, Saline Valley and Death Valley, California

    NASA Astrophysics Data System (ADS)

    Schubert, Brian A.; Lowenstein, Tim K.; Timofeeff, Michael N.

    2009-06-01

    Primary fluid inclusions in halite crystallized in Saline Valley, California, in 1980, 2004-2005, and 2007, contain rod- and coccoid-shaped microparticles the same size and morphology as archaea and bacteria living in modern brines. Primary fluid inclusions from a well-dated (0-100,000 years), 90 m long salt core from Badwater Basin, Death Valley, California, also contain microparticles, here interpreted as halophilic and halotolerant prokaryotes. Prokaryotes are distinguished from crystals on the basis of morphology, optical properties (birefringence), and uniformity of size. Electron micrographs of microparticles from filtered modern brine (Saline Valley), dissolved modern halite crystals (Saline Valley), and dissolved ancient halite crystals (Death Valley) support in situ microscopic observations that prokaryotes are present in fluid inclusions in ancient halite. In the Death Valley salt core, prokaryotes in fluid inclusions occur almost exclusively in halite precipitated in perennial saline lakes 10,000 to 35,000 years ago. This suggests that trapping and preservation of prokaryotes in fluid inclusions is influenced by the surface environment in which the halite originally precipitated. In all cases, prokaryotes in fluid inclusions in halite from the Death Valley salt core are miniaturized (<1 μm diameter cocci, <2.5 μm long, very rare rod shapes), which supports interpretations that the prokaryotes are indigenous to the halite and starvation survival may be the normal response of some prokaryotes to entrapment in fluid inclusions for millennia. These results reinforce the view that fluid inclusions in halite and possibly other evaporites are important repositories of microbial life and should be carefully examined in the search for ancient microorganisms on Earth, Mars, and elsewhere in the Solar System.

  5. Observations of coastal sediment dynamics of the Tijuana Estuary Fine Sediment Fate and Transport Demonstration Project, Imperial Beach, California

    USGS Publications Warehouse

    Warrick, Jonathan A.; Rosenberger, Kurt J.; Lam, Angela; Ferreiera, Joanne; Miller, Ian M.; Rippy, Meg; Svejkovsky, Jan; Mustain, Neomi

    2012-01-01

    Coastal restoration and management must address the presence, use, and transportation of fine sediment, yet little information exists on the patterns and/or processes of fine-sediment transport and deposition for these systems. To fill this information gap, a number of State of California, Federal, and private industry partners developed the Tijuana Estuary Fine Sediment Fate and Transport Demonstration Project ("Demonstration Project") with the purpose of monitoring the transport, fate, and impacts of fine sediment from beach-sediment nourishments in 2008 and 2009 near the Tijuana River estuary, Imperial Beach, California. The primary purpose of the Demonstration Project was to collect and provide information about the directions, rates, and processes of fine-sediment transport along and across a California beach and nearshore setting. To achieve these goals, the U.S. Geological Survey monitored water, beach, and seafloor properties during the 2008–2009 Demonstration Project. The project utilized sediment with ~40 percent fine sediment by mass so that the dispersal and transport of fine sediment would be easily recognizable. The purpose of this report is to present and disseminate the data collected during the physical monitoring of the Demonstration Project. These data are available online at the links noted in the "Additional Digital Information" section. Synthesis of these data and results will be provided in subsequent publications.

  6. 76 FR 41745 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-15

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule... Valley Unified Air Pollution Control District portion of the California State Implementation Plan (SIP... Valley Unified Air Pollution Control District (SJVUAPCD) Rule 4682, Polystyrene, Polyethylene,...

  7. 78 FR 21581 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-11

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Antelope Valley Air Quality... the Antelope Valley Air Quality Management District (AVAQMD), Monterey Bay Unified Air...

  8. 77 FR 26475 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-04

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Antelope Valley Air Quality... the Antelope Valley Air Quality Management District (AVAQMD), Eastern Kern Air Pollution...

  9. Secret World of the Forbidden City: Splendors from Imperial China, 1644-1911 and Change and Continuity: Chinese Americans in California. Exhibition Information and Curriculum Guide for Teachers Grades 2-11.

    ERIC Educational Resources Information Center

    2000

    The materials in this curriculum guide were designed to prepare teachers and students in grades 2-11 for the "Secret World of the Forbidden City: Splendors from China's Imperial Palace 1644-1911" exhibition at the Oakland Museum of California Education Department, to inform teachers and students about Imperial China, and to illuminate the…

  10. Land use and water use in the Antelope Valley, California

    USGS Publications Warehouse

    Templin, W.E.; Phillips, S.P.; Cherry, D.E.; DeBortoli, M.L.; Haltom, T.C.; McPherson, K.R.; Mrozek, C.A.

    1995-01-01

    Urban land use and water use in the Antelope Valley, California, have increased greatly since the devel- opment of the valley began in the late 1800's. Ground water always has been a major source of supply in this area because of limited local surface-water resources. Ground-water pumpage reportedly increased from about 29,000 acre-feet in 1919 to about 400,000 acre-feet in the 1950's. Declines in ground-water levels and increased costs of electrical power in the 1970's resulted in a reduction in the quantity of ground-water pumped annually for irrigation uses. Ground-water pumpage was further reduced in the 1970's following the completion of the California Aqueduct, which conveys water from northern California. Total annual reported ground-water pumpage decreased to a low of about 53,200 acre-feet in 1983 and increased again to about 91,700 acre-feet in 1991. Rapid urban development and the 1987-92 drought renewed concern about a possible return to extensive ground-water- storage depletion and increased land subsidence. Water-demand forecasts in 1980 for the Antelope Valley indicated that total annual demand by the year 2020 was expected to be about 250,000 acre- feet per year, with agricultural uses to be about 65 percent of this total demand. In 1990, total demand. In 1993, preliminary forecasts for total demand for 2010 ranged from about 127,000 to 329,000 acre-feet with urban water uses accounting for all but a few percent of the total anticipated demand. This history of forecasts indicates that expectations change with time. Factors that affect water demand change and different forecasting methods are used. Water-conservation options may be adopted to employ best-management practices that would further influence future water demands in the Antelope Valley.

  11. Landslide oil field, San Joaquin Valley, California

    SciTech Connect

    Collins, B.P.; March, K.A.; Caballero, J.S.; Stolle, J.M.

    1988-03-01

    The Landslide field, located at the southern margin of the San Joaquin basin, was discovered in 1985 by a partnership headed by Channel Exploration Company, on a farm out from Tenneco Oil Company. Initial production from the Tenneco San Emidio 63X-30 was 2064 BOPD, making landslide one of the largest onshore discoveries in California during the past decade. Current production is 7100 BOPD from a sandstone reservoir at 12,500 ft. Fifteen wells have been drilled in the field, six of which are water injectors. Production from the Landslide field occurs from a series of upper Miocene Stevens turbidite sandstones that lie obliquely across an east-plunging structural nose. These turbidite sandstones were deposited as channel-fill sequences within a narrowly bounded levied channel complex. Both the Landslide field and the larger Yowlumne field, located 3 mi to the northwest, comprise a single channel-fan depositional system that developed in the restricted deep-water portion of the San Joaquin basin. Information from the open-hole logs, three-dimensional surveys, vertical seismic profiles, repeat formation tester data, cores, and pressure buildup tests allowed continuous drilling from the initial discovery to the final waterflood injector, without a single dry hole. In addition, the successful application of three-dimensional seismic data in the Landslide development program has helped correctly image channel-fan anomalies in the southern Maricopa basin, where data quality and severe velocity problems have hampered previous efforts. New exploration targets are currently being evaluated on the acreage surrounding the Landslide discovery and should lead to an interesting new round of drilling activity in the Maricopa basin.

  12. Fog and Haze in California's San Joaquin Valley

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This illustration features images of southern California and southwestern Nevada acquired on January 3, 2001 (Terra orbit 5569), and includes data from three of MISR's nine cameras. The San Joaquin Valley, which comprises the southern extent of California's Central Valley, covers much of the viewed area. Also visible are several of the Channel Islands near the bottom, and Mono and Walker Lakes, which stand out as darker patches near the top center, especially in the vertical and backward oblique images. Near the lower right of each image is the Los Angeles Basin, with the distinctive chevron shape of the Mojave Desert to its north.

    The Central Valley is a well-irrigated and richly productive agricultural area situated between the Coast Range and the snow-capped Sierra Nevadas. During the winter, the region is noted for its hazy overcasts and a low, thick ground fog known as the Tule. Owing to the effects of the atmosphere on reflected sunlight, dramatic differences in the MISR images are apparent as the angle of view changes. An area of thick, white fog in the San Joaquin Valley is visible in all three of the images. However, the pervasive haze that fills most of the valley is only slightly visible in the vertical view. At the oblique angles, the haze is highly distinguishable against the land surface background, particularly in the forward-viewing direction. Just above image center, the forward view also reveals bluish-tinged plumes near Lava Butte in Sequoia National Forest, where the National Interagency Coordination Center reported an active forest fire.

    The changing surface visibility in the multi-angle data allows us to derive the amount of atmospheric haze. In the lower right quadrant is a map of haze amount determined from automated processing of the MISR imagery. Low amounts of haze are shown in blue, and a variation in hue through shades of green, yellow, and red indicates progressively larger amounts of airborne particulates. Due to the

  13. Mapping Evapotranspiration over Agricultural Land in the California Central Valley

    NASA Astrophysics Data System (ADS)

    Melton, F. S.; Huntington, J. L.; Guzman, A.; Johnson, L.; Morton, C.; Nemani, R. R.; Post, K. M.; Rosevelt, C.; Shupe, J. W.; Spellenberg, R.; Vitale, A.

    2015-12-01

    Recent advances in satellite mapping of evapotranspiration (ET) have made it possible to largely automate the process of mapping ET over large areas at the field-scale. This development coincides with recent drought events across the western U.S. which have intensified interest in mapping of ET and consumptive use to address a range of water management challenges, including resolving disputes over water rights, improving irrigation management, and developing sustainable management plans for groundwater resources. We present a case study for California that leverages two automated ET mapping capabilities to estimate ET at the field scale over agricultural areas in the California Central Valley. We utilized the NASA Earth Exchange and applied a python-based implementation of the METRIC surface energy balance model and the Satellite Irrigation Management Support (SIMS) system, which uses a surface reflectance-based approach, to map ET over agricultural areas in the Central Valley. We present estimates from 2014 from both approaches and results from a comparison of the estimates. Though theoretically and computationally quite different from each other, initial results from both approaches show good agreement overall on seasonal ET totals for 2014. We also present results from comparisons against ET measurements collected on commercial farms in the Central Valley and discuss implications for accuracy of the two different approaches. The objective of this analysis is to provide data that can inform planning for the development of sustainable groundwater management plans, and assist water managers and growers in evaluating irrigation demand during drought events.

  14. Rock-fall potential in the Yosemite Valley, California

    USGS Publications Warehouse

    Wieczorek, G.F.; Morrissey, M.M.; Iovine, Giulio; Godt, Jonathan

    1999-01-01

    We used two methods of estimating rock-fall potential in the Yosemite Valley, California based on (1) physical evidence of previous rock-fall travel, in which the potential extends to the base of the talus, and (2) theoretical potential energy considerations, in which the potential can extend beyond the base of the talus, herein referred to as the rock-fall shadow. Rock falls in the valley commonly range in size from individual boulders of less than 1 m3 to moderate-sized falls with volumes of about 100,000 m3. Larger rock falls exceeding 100,000 m3, referred to as rock avalanches, are considered to be much less likely to occur based on the relatively few prehistoric rock-fall avalanche deposits in the Yosemite Valley. Because the valley has steep walls and is relatively narrow, there are no areas that are absolutely safe from large rock avalanches. The map shows areas of rock-fall potential, but does not predict when or how frequently a rock fall will occur. Consequently, neither the hazard in terms of probability of a rock fall at any specific location, nor the risk to people or facilities to such events can be assessed from this map.

  15. Impact of Air Pollution on California Central Valley Fog Frequency

    NASA Astrophysics Data System (ADS)

    Gray, E.; Baldocchi, D. D.; Goldstein, A. H.

    2015-12-01

    Throughout the 20th century, trends in California Central Valley fog frequency have changed dramatically without explanation. While episodes of dense radiation fog, known regionally as Tule Fog, increased steadily from 1930-1970, analysis from both ground and remote sensing measurements confirm a 46-50% reduction in fog days in the last 30 years (Baldocchi and Waller, 2014, Herkes et al., 2014). The dominant hypotheses suggest that the recent decline in radiation fog can be explained by the rising temperatures associated with climate change or urban heat island effect. This assertion fails to explain the significant increase in Central Valley fog midcentury. Here we instead assert that changes in air pollution, rather than climate, better support this upward then downward temporal trend. Automobile use greatly increased emissions of nitrogen oxide (NOx) midcentury, followed by a large decrease in vehicle emissions due to statewide regulation from 1980 to present. In the Central Valley, NOx from automobile emissions contributes to the formation ammonium nitrate (NH4NO3), the dominant hygroscopic aerosol in the valley's wintertime boundary layer that can act as cloud condensation nuclei (CCN) necessary for fog droplet formation. Thus, changes in air pollution not only affect the number of CCN, but may also impact the density and persistence of fog episodes. Using NOAA meteorological records throughout the twentieth century, we will show the correlation between fog frequency, air pollution, and climatic drivers. We conclude that fog trends are closely correlated with changes in air pollution, rather than solely climate change.

  16. Faulting history of the Long Valley caldera, eastern California

    SciTech Connect

    Foster, J.G. . School of Natural Science)

    1993-03-01

    The faulting history that produced the Sierra Nevada Range can be seen, in part, on the eastern contact of the Sierra Nevada Block with the Owens Valley Block. By surveying a series of remnant lake shore lines in the Long Valley Caldera of eastern California, the deformation and faulting history of the area can be inferred. These beaches are ideal for studying the faulting history of the area as their location is so near the contact of the two plates. The caldera sits on the Owens Valley Block just east of the major fault which separates it from the Sierra Nevada Block. It encompasses a ten mile by twenty mile area, which was filled with a lake after its creation some 730,000 years ago. Over time, the lake slowly lowered due to erosion of its sill, successive upward tilting of the Sierra Nevada Block, and consequent downward tilting of the Owens Valley Block. These changes in the attitude of the caldera floor and the beaches of the lake left the successive, non-parallel shore lines that have now been surveyed, mapped, and dated relative to each other. Together with the regional structures and history of the area, the remnant deformed shore lines can be used to develop a picture of the faulting history of the area and its relation to the rising of the Sierra Nevada Mountains.

  17. Ground Watering of the Death Valley Region, Nevada and California

    SciTech Connect

    USGS

    2006-10-12

    Water is a precious commodity, especially in the arid southwest region of the US, where there is a limited supply of both surface water and ground water. Ground water has a variety of uses (such as agricultural, commercial, and domestic) in the Death Valley regional ground-water flow system (DVRFS) of southern Nevada and eastern California. The DVRFS, an area of about 100,000 square kilometers, contains very complex geology and hydrology. Using a computer model to represent this complex system the US Geological Survey (USGS) simulated ground-water flow in the Death Valley region for use with US Department of Energy (DOE) projects in southern Nevada. The model was created to help address contaminant cleanup activities associated with the underground nuclear testing conducted from 1951 to 1992 at the Nevada Test Site and to support the licensing process for the Nation's proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada.

  18. Geological literature on the San Joaquin Valley of California

    USGS Publications Warehouse

    Maher, J.C.; Trollman, W.M.; Denman, J.M.

    1973-01-01

    The following list of references includes most of the geological literature on the San Joaquin Valley and vicinity in central California (see figure 1) published prior to January 1, 1973. The San Joaquin Valley comprises all or parts of 11 counties -- Alameda, Calaveras, Contra Costa, Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, and Tulare (figure 2). As a matter of convenient geographical classification the boundaries of the report area have been drawn along county lines, and to include San Benito and Santa Clara Counties on the west and Mariposa and Tuolumne Counties on the east. Therefore, this list of geological literature includes some publications on the Diablo and Temblor Ranges on the west, the Tehachapi Mountains and Mojave Desert on the south, and the Sierra Nevada Foothills and Mountains on the east.

  19. SRTM Perspective View with Landsat Overlay: San Joaquin Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    San Joaquin, the name given to the southern portion of California's vast Central Valley, has been called the world's richest agricultural valley. In this perspective view generated using data from the Shuttle Radar Topography Mission and an enhanced Landsat image, we are looking toward the southwest over a checkerboard pattern of agricultural fields. Mt. Pinos, a popular location for stargazing at 2,692 meters (8,831 feet) looms above the valley floor and is visible on the left side of the image. The productive southern San Joaquin is in reality a desert, averaging less than 12.7 cm (5 inches) of rain per year. Through canals and irrigation, the region nurtures some two hundred crops including grapes, figs, apricots, oranges, and more than 4,047 square-km (1,000,000 acres) of cotton. The California Aqueduct, transporting water from the Sacramento River Delta through the San Joaquin, runs along the base of the low-lying Wheeler Ridge on the left side of the image. The valley is not all agriculture though. Kern County, near the valley's southern end, is the United States' number one oil producing county, and actually produces more crude oil than Oklahoma. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors, from Landsat data, approximate natural color.

    The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U

  20. Visitor center at the Antelope Valley California Poppy Reserve, Lancaster, California

    SciTech Connect

    Colyer, R.D.; Freeman, S.P.

    1981-01-01

    The Antelope Valley California Poppy Reserve contains the largest remaining stand of the California Poppy (Eschschozia Californica), the state flower of California. To welcome the thousands of people viewing the desert wildflowers each spring, the State of California decided to build a visitor/interpretive center. This building deals primarily with the question of fit; a building's fit aesthetically with its site and the fit of a building's design response to the climate of the site. In this case, both aspects of this question led the client and architects to seek an earth sheltered solution using materials at least metaphorically indigenous to the region. On both a technical and formal level, this building seeks to fit the unique climate and historical heritage of its site.

  1. 77 FR 74355 - Approval of Air Quality Implementation Plans; California; San Joaquin Valley; Attainment Plan for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-14

    ... AGENCY 40 CFR Part 52 Approval of Air Quality Implementation Plans; California; San Joaquin Valley... Quality Standards in the San Joaquin Valley. This technical amendment corrects the CFR to properly codify the California Air Resources Board's commitment to update the air quality modeling in the San...

  2. Contaminated fish consumption in California's Central Valley Delta.

    PubMed

    Shilling, Fraser; White, Aubrey; Lippert, Lucas; Lubell, Mark

    2010-05-01

    Extensive mercury contamination and angler selection of the most contaminated fish species coincide in California's Central Valley. This has led to a policy conundrum: how to balance the economic and cultural impact of advising subsistence anglers to eat less fish with the economic cost of reducing the mercury concentrations in fish? State agencies with regulatory and other jurisdictional authority lack sufficient data and have no consistent approach to this problem. The present study focused on a critical and contentious region in California's Central Valley (the Sacramento-San Joaquin Rivers Delta) where mercury concentrations in fish and subsistence fishing rates are both high. Anglers and community members were surveyed for their fish preferences, rates of consumption, the ways that they receive health information, and basic demographic information. The rates of fish consumption for certain ethnicities were higher than the rates used by state agencies for planning pollution remediation. A broad range of ethnic groups were involved in catching and eating fish. The majority of anglers reported catching fish in order to feed to their families, including children and women of child-bearing age. There were varied preferences for receiving health information and no correlation between knowledge of fish contamination and rates of consumption. Calculated rates of mercury intake by subsistence anglers were well above the EPA reference dose. The findings here support a comprehensive policy strategy of involvement of the diverse communities in decision-making about education and clean-up and an official recognition of subsistence fishers in the region. PMID:20176346

  3. Evapotranspiration of applied water, Central Valley, California, 1957-78

    USGS Publications Warehouse

    Williamson, Alex K.

    1982-01-01

    In the Central Valley, Calif., where 57% of the 20,000 square miles of land is irrigated, ground-water recharge from agricultural lands is an important input to digital simulation models of ground-water flow. Several methods of calculating recharge were explored for the Central Valley Aquifer Project and a simplified water budget was designed where net recharge (recharge minus pumpage) equals net surface water diverted minus evapotranspiration of applied water (ETAW). This equation eliminates the need to determine pumpage from the water-table aquifer, assuming that the time lag for infiltration is not longer than the time intervals of interest for modeling. This study evaluates only the evapotranspiration of applied water. Future reports will describe the other components of the water budget. ETAW was calculated by summing the products of ETAW coefficients and respective crop areas for each 7 1/2-minute quadrangle area in the valley, for each of three land-use surveys between 1957 and 1978. In 1975 total ETAW was 15.2 million acre-feet, a 43% increase since 1959. The largest increases were in the south, especially Kern County, which had a sixfold increase, which was caused by the import of surface water in the California Aqueduct. (USGS)

  4. Statistical modeling of valley fever data in Kern County, California

    NASA Astrophysics Data System (ADS)

    Talamantes, Jorge; Behseta, Sam; Zender, Charles S.

    2007-03-01

    Coccidioidomycosis (valley fever) is a fungal infection found in the southwestern US, northern Mexico, and some places in Central and South America. The fungus that causes it ( Coccidioides immitis) is normally soil-dwelling but, if disturbed, becomes air-borne and infects the host when its spores are inhaled. It is thus natural to surmise that weather conditions that foster the growth and dispersal of the fungus must have an effect on the number of cases in the endemic areas. We present here an attempt at the modeling of valley fever incidence in Kern County, California, by the implementation of a generalized auto regressive moving average (GARMA) model. We show that the number of valley fever cases can be predicted mainly by considering only the previous history of incidence rates in the county. The inclusion of weather-related time sequences improves the model only to a relatively minor extent. This suggests that fluctuations of incidence rates (about a seasonally varying background value) are related to biological and/or anthropogenic reasons, and not so much to weather anomalies.

  5. Statistical modeling of valley fever data in Kern County, California.

    PubMed

    Talamantes, Jorge; Behseta, Sam; Zender, Charles S

    2007-03-01

    Coccidioidomycosis (valley fever) is a fungal infection found in the southwestern US, northern Mexico, and some places in Central and South America. The fungus that causes it (Coccidioides immitis) is normally soil-dwelling but, if disturbed, becomes air-borne and infects the host when its spores are inhaled. It is thus natural to surmise that weather conditions that foster the growth and dispersal of the fungus must have an effect on the number of cases in the endemic areas. We present here an attempt at the modeling of valley fever incidence in Kern County, California, by the implementation of a generalized auto regressive moving average (GARMA) model. We show that the number of valley fever cases can be predicted mainly by considering only the previous history of incidence rates in the county. The inclusion of weather-related time sequences improves the model only to a relatively minor extent. This suggests that fluctuations of incidence rates (about a seasonally varying background value) are related to biological and/or anthropogenic reasons, and not so much to weather anomalies. PMID:17120065

  6. 78 FR 75332 - Proposed Information Collection; Comment Request; California Central Valley Angler Survey

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-11

    ...; California Central Valley Angler Survey AGENCY: National Oceanic and Atmospheric Administration (NOAA... (Sacramento River winter Chinook, Central Valley spring Chinook, Central Valley steelhead). The survey is... restoration. II. Method of Collection A random sample of recreational anglers who fish on Central...

  7. 77 FR 70707 - Approval of Air Quality Implementation Plans; California; San Joaquin Valley and South Coast...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-27

    ... AGENCY 40 CFR Part 52 Approval of Air Quality Implementation Plans; California; San Joaquin Valley and... Ambient Air Quality Standards in the San Joaquin Valley and the South Coast Air Basin. These technical...) in the San Joaquin Valley and South Coast (Los Angeles) Air Basin and included provisions of...

  8. Yuma District Resource Management Plan, Yuma, La Paz, and Mohave Counties, Arizona and San Bernardino, Riverside and Imperial Counties, California

    SciTech Connect

    Not Available

    1985-08-01

    Implementation of a resource management plan is proposed for 1.2 million acres within the 2.7-million-acre Yuma District, located in Yuma, La Paz, and Mohave counties, Arizona and San Bernardino, Riverside, and Imperial counties, California. Under the preferred alternative, wildlife habitat would be a priority consideration on approximately 247,740 acre, and nine special management areas would be designated. A portion of the Cactus Plain and the Chemehuevi/Needles wilderness study areas would be recommended for wilderness designation. Two areas totaling 31,360 acres would be designated as special management areas, and another six areas totaling 155,705 acres would be managed to protect their natural values. Livestock grazing would be authorized at 3998 animal unit months on four allotments. Approximately 55,490 acres of federal lands would be available for disposal and 31,220 acres would be acquired. Nine utility corridors and nine communication sites would be designated. Existing recreational facilities would be maintained, with additional facilities provided when warranted. Along Parker Strip, only floodproofed day-use facilities would be allowed within the 100-year flood plain. Off-road vehicle (ORV) use designations would be made on 640 acres and ORV use in the remainder of the district would be limited to existing roads and trails. Continuous occupancy of mobile home sites would be restricted to one five-month period in a single year. Permanent residential use would be phased out.

  9. Victor Valley College Agreement between the Victor Valley Community College District and the Victor Valley College California Teachers Association Chapter 1170. July 1989 - June 1992.

    ERIC Educational Resources Information Center

    Victor Valley Community Coll. District, Victorville, CA.

    The collective bargaining agreement between the Victor Valley College Board of Trustees and the Victor Valley College California Teachers Association/National Education Association is presented. This contract, covering the period from July 1989 through June 1992, deals with the following topics: bargaining agent recognition; district and…

  10. Faulting caused by groundwater level declines, San Joaquin Valley, California.

    USGS Publications Warehouse

    Holzer, T.L.

    1980-01-01

    Approximately 230mm of aseismic vertical offset of the land surface across the Pond-Poso Creek fault in the San Joaquin Valley, California, probably is related to groundwater withdrawal for crop irrigation. The scarp is approximately 3.4km long and occurs in an area where the land subsided more than 1.5m from 1926 to 1970. Modern faulting postdates the beginning of water level declines and associated subsidence. Movement detected by precise leveling surveys from February 1977 to March 1979 was seasonal, occurring during periods of water level decline. The modern movement probably is caused by localized differential compaction induced by differential water level declines across the preexisting fault. -Author

  11. Late Holocene vegetation changes in Greenwater Valley, Mojave Desert, California

    USGS Publications Warehouse

    Cole, K.L.; Webb, R.H.

    1985-01-01

    Small-scale late Holocene vegetation changes were determined from a series of 13 modern and fossil packrat middens collected from a site in the Greenwater Valley, northern Mojave Desert, California. Although the site is above the modern lower limit of Coleogyne ramosissima (black-brush), macrofossils of this shrub are only present in samples younger than 270 yr B.P. In order to measure changes more subtle than presence vs absence, macrofossil concentrations were quantified, and principal components and factor analyses were used to distinguish midden plant assemblages. Both the presence/absence data and the statistical analyses suggest a downward shift of 50 to 100 m for Coleogyne (blackbrush) communities between 1435 and 1795 A.D. ?? 1985.

  12. Late Cenozoic sedimentation in Pilot Knob Valley, California

    NASA Astrophysics Data System (ADS)

    Rittase, W. M.; Walker, J. D.; Kirby, E.; Andrew, J.; Wan, E.

    2012-12-01

    In Pilot Knob Valley (PKV), active inversion of a Pliocene-mid Pleistocene basin presents the opportunity to understand the spatial and temporal development of an enigmatic basin astride a major transform boundary in California. Here, a ~1000-m-thick package of exposed Late Cenozoic strata has been uplifted and tilted to the northeast. Based on new age and provenance data, we adopt the name Pilot Knob formation (PKfm) to describe much of these exposed rocks north of the Garlock fault (GF) and east of Christmas Canyon gate. Post-Miocene development of PKV is strongly influenced by the sinistral GF, the newly identified Marine Gate fault (MGF) and dextral Eastern California shear zone. The PKfm consists of three lithofacies members, from base to top: (1) rocks derived from Eagle Crags to the south; (2) Randsburg Wash lacustrine rocks; and (3) an upper member derived from the Slate Range. Tephrochronologic data from four PKfm ash samples brackets deposition of lacustrine Randsburg Wash Member rocks between 3.7-3.1 Ma and lacustrine rocks of the Slate Range Member between 1.2-0.6 Ma. A fifth tephrochronologic sample from lacustrine-distal alluvial sediments south of the GF near Christmas Canyon brackets deposition of a possible PKfm facies at ~3.1 Ma. A 3-stage tectonic model for northern PKV explains changing provenance patterns. Prior to ~3.1 Ma, the western PKV paleo-low lay north of the current GF adjacent to the southern Slate Range and connected to Searles Valley. The MGF cuts adjacent to the southern face of the Slate Range and southern Searles Valley with up to 7.5 km of sinistral oblique-normal slip between ~5-2.5 Ma. Eagle Crags fanglomerate deposition may continue after 3.7 Ma west of the Randsburg Wash-Searles Valley spillway, but these rocks have been eroded away. By ~3.7 Ma, northward progradation of Eagle Crags fanglomerate waned and lacustrine sediments were deposited north of the GF and east of the Randsburg Wash-Searles Valley spillway. At ~3.1 Ma

  13. Sustainability of irrigated agriculture in the San Joaquin Valley, California

    PubMed Central

    Schoups, Gerrit; Hopmans, Jan W.; Young, Chuck A.; Vrugt, Jasper A.; Wallender, Wesley W.; Tanji, Ken K.; Panday, Sorab

    2005-01-01

    The sustainability of irrigated agriculture in many arid and semiarid areas of the world is at risk because of a combination of several interrelated factors, including lack of fresh water, lack of drainage, the presence of high water tables, and salinization of soil and groundwater resources. Nowhere in the United States are these issues more apparent than in the San Joaquin Valley of California. A solid understanding of salinization processes at regional spatial and decadal time scales is required to evaluate the sustainability of irrigated agriculture. A hydro-salinity model was developed to integrate subsurface hydrology with reactive salt transport for a 1,400-km2 study area in the San Joaquin Valley. The model was used to reconstruct historical changes in salt storage by irrigated agriculture over the past 60 years. We show that patterns in soil and groundwater salinity were caused by spatial variations in soil hydrology, the change from local groundwater to snowmelt water as the main irrigation water supply, and by occasional droughts. Gypsum dissolution was a critical component of the regional salt balance. Although results show that the total salt input and output were about equal for the past 20 years, the model also predicts salinization of the deeper aquifers, thereby questioning the sustainability of irrigated agriculture. PMID:16230610

  14. Biostratigraphy of marine Pliocene-Pleistocene deposits, Simi Valley, California

    SciTech Connect

    Groves, L.T.; Squires, R.L.

    1988-03-01

    Richly fossiliferous, marine deltaic deposits exposed in the northern Simi Valley, southern California, are important biostratigraphically because they straddle the Pliocene-Pleistocene boundary. These deposits consist of fine to coarse-grained sandstone with interbedded conglomerate. The best exposure is in Gilibrand Quarry, where 250 m are exposed in a continuous section with four main fossiliferous zones rich in mollusks. Most of these mollusks are complete and display growth series that represent a life assemblage with minimal postmortem transport. An erosional surface is present between the second and third fossiliferous beds in the quarry. Beds below the erosional surface contain mollusks indicative of Pliocene age. These mollusks are the pectinid Patinopecten healeyi and the epitoniid gastropod Opalia varicostata. Beds above the erosional surface contain a calcareous nannofossil assemblage that suggests a Pleistocene age. These species are Coccolithus pelagicus, Helicosphaera carteri, and Dictyococcites productus. (An absence of discoaster species and Emiliana huxleyi would place this assemblage in the early or medial Pleistocene.) The name lower Saugus Formation is assigned to all of these marine Pliocene-Pleistocene deposits because W.S. W. Kew in 124 originally named and mapped these strata as Saugus Formation. Confusion will be avoided by discontinuing usage of the names Fernando Formation, Pico Formation, and Sunshine Ranch Member of the Saugus Formation in this area for these strata. The lower Saugus Formation in the Simi Valley is faunally similar and time-correlate with the San Diego Formation in San Diego County.

  15. Slip on faults in the Imperial Valley triggered by the 4 April 2010 Mw 7.2 El Mayor-Cucapah earthquake revealed by InSAR

    NASA Astrophysics Data System (ADS)

    Wei, Meng; Sandwell, David; Fialko, Yuri; Bilham, Roger

    2011-01-01

    Radar interferometry (InSAR), field measurements and creepmeters reveal surface slip on multiple faults in the Imperial Valley triggered by the main shock of the 4 April 2010 El Mayor-Cucapah Mw 7.2 earthquake. Co-seismic offsets occurred on the San Andreas, Superstition Hills, Imperial, Elmore Ranch, Wienert, Coyote Creek, Elsinore, Yuha, and several minor faults near the town of Ocotillo at the northern end of the mainshock rupture. We documented right-lateral slip (<40 mm) on northwest-striking faults and left-lateral slip (<40 mm) on southwest-striking faults. Slip occurred on 15-km- and 20-km-long segments of the San Andreas Fault in the Mecca Hills (≤50 mm) and Durmid Hill (≤10 mm) respectively, and on 25 km of the Superstition Hills Fault (≤37 mm). Field measurements of slip on the Superstition Hills Fault agree with InSAR and creepmeter measurements to within a few millimeters. Dislocation models of the InSAR data from the Superstition Hills Fault confirm that creep in this sequence, as in previous slip events, is confined to shallow depths (<3 km).

  16. Geothermal fluids to irrigate energy crops on Imperial East Mesa Desert, California

    SciTech Connect

    Robinson, F.E.; Thomas, T.R.; Singh, K.

    1981-10-01

    Geothermal fluid at 2200 parts per million(ppM) total dissolved solids from the East Mesa, California was compared to 1400 ppM ground water from a 100 m well as irrigation sources for Beta vulgaris (L.) USH-11 sugar beet and Tamarix aphylla (L.) athel, a biomass and windbreak tree. In 1980 there was no significant difference between the yields from the two waters. In 1981, there was no significant difference between biomass production from the waters on the athel. The geothermal water produced a larger yield of sucrose than the ground water. The data suggest that raising sugar beets with either water is feasible on the East Mesa.

  17. 78 FR 16827 - Designation of Areas for Air Quality Planning Purposes; State of California; Imperial Valley...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ... crestline of the Chocolate Mountains. If EPA receives adverse comments, EPA will withdraw the direct final rule, and it will not take effect. EPA will address all public comments in a subsequent final...

  18. Heber Ethanol Fuel Facility, Imperial Valley, California. Quarterly report No. 2, March 1981-May 1981

    SciTech Connect

    Not Available

    1981-08-01

    The purposed project is a commercial-scale ethanol-fuel facility with a capacity of twenty million gallons per year of fuel-grade ethanol. In addition, 70,000 tons per year of distillers dried grains will be produced. The following tasks and issues are addressed: process engineering - process descriptions, plant layout, and design; economics and finance - overview of capital and operating costs; environmental analysis - preliminary project description; and permit processing and legal issues. (MHR)

  19. Preliminary results of geothermal desalting operations at the East Mesa test site Imperial Valley, California

    NASA Technical Reports Server (NTRS)

    Suemoto, S. H.; Mathias, K. E.

    1974-01-01

    The Bureau of Reclamation has erected at its Geothermal Resource Development site two experimental test vehicles for the purpose of desalting hot fluids of geothermal origin. Both plants have as a feed source geothermal well Mesa 6-1 drilled to a total depth of 8,030 feet and having a bottom hole temperature of 400 F. Formation fluid collected at the surface contained 24,800 mg/1 total dissolved solids. The dissolved solids consist mainly of sodium chloride. A multistage distillation (3-stage) plant has been operated intermittently for one year with no operational problems. Functioning at steady-state conditions with a liquid feed rate of 70 g/m and a temperature of 221 F, the final brine blowdown temperature was 169 F. Product water was produced at a rate of about 2 g/m; average total dissolved solids content of the product was 170 mg/1. A product quality of 27.5 mg/1 at a pH of 9.5 was produced from the first stage.

  20. 78 FR 16792 - Designation of Areas for Air Quality Planning Purposes; State of California; Imperial Valley...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-19

    ..., Arizona. On October 31, 1990 (55 FR 45799), EPA clarified the descriptions of several Group I and II areas... nonattainment area by operation of law effective November 15, 1990. On March 15, 1991 (56 FR 11101), EPA...'' PM 10 nonattainment area. On November 6, 1991 (56 FR 56694), EPA codified the PM 10...

  1. Salton Sea Geothermal Field, Imperial Valley, California as a site for continental scientific drilling. [Abstract only

    SciTech Connect

    Elders, W.A.; Cohen, L.H.

    1983-03-01

    The Salton Trough, where seafloor spreading systems of the East Pacific Rise transition into the San Andreas transform fault system, is the site of such continental rifting and basin formation today. The largest thermal anomaly in the trough, the Salton Sea Geothermal Field (SSGF), is of interest to both thermal regimes and mineral resources investigators. At this site, temperatures >350/sup 0/C and metal-rich brines with 250,000 mg/L TDS have been encountered at <2 km depth. Republic Geothermal Inc. will drill a new well to 3.7 km in the SSGF early in 1983; we propose add-on experiments in it. If funded, we will obtain selective water and core samples and a large-diameter casing installed to 3.7 km will permit later deepening. In Phase 2, the well would be continuously cored to 5.5 km and be available for scientific studies until July 1985. The deepened well would encounter hydrothermal regimes of temperature and pressure never before sampled.

  2. Geophysical, geochemical, and geological investigations of the Dunes geothermal system, Imperial Valley, California

    NASA Technical Reports Server (NTRS)

    Elders, W. A.; Combs, J.; Coplen, T. B.; Kolesar, P.; Bird, D. K.

    1974-01-01

    The Dunes anomaly is a water-dominated geothermal system in the alluvium of the Salton Trough, lacking any surface expression. It was discovered by shallow-temperature gradient measurements. A 612-meter-deep test well encountered several temperature-gradient reversals, with a maximum of 105 C at 114 meters. The program involves surface geophysics, including electrical, gravity, and seismic methods, down-hole geophysics and petrophysics of core samples, isotopic and chemical studies of water samples, and petrological and geochemical studies of the cores and cuttings. The aim is (1) to determine the source and temperature history of the brines, (2) to understand the interaction between the brines and rocks, and (3) to determine the areal extent, nature, origin, and history of the geothermal system. These studies are designed to provide better definition of exploration targets for hidden geothermal anomalies and to contribute to improved techniques of exploration and resource assessment.

  3. Chemistry and geothermometry of brine produced from the Salton Sea Scientific drill hole, Imperial Valley, California

    USGS Publications Warehouse

    Thompson, J.M.; Fournier, R.O.

    1988-01-01

    The December 29-30, 1985, flow test of the State 2-14 well, also known as the Salton Sea Scientific drill hole, produced fluid from a depth of 1865-1877 m at a reservoir temperature of 305????5??C. Samples were collected at five different flashing pressures. The brines are Na-Ca-K-Cl-type waters with very high metal and low SO4 and HCO3 contents. Compositions of the flashed brines were normalized relative to the 25??C densities of the solutions, and an ionic charge balance was achieved by adjusting the Na concentration. Calculated Na/K geothermometer temperatures, using equations suggested by different investigators, range from 326?? to 364??C. The Mg/K2 method gives a temperature of about 350??C, Mg/Li2 about 282??, and Na/Li 395??-418??C. -from Authors

  4. Color Image of Death Valley, California from SIR-C

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This radar image shows the area of Death Valley, California and the different surface types in the area. Radar is sensitive to surface roughness with rough areas showing up brighter than smooth areas, which appear dark. This is seen in the contrast between the bright mountains that surround the dark, smooth basins and valleys of Death Valley. The image shows Furnace Creek alluvial fan (green crescent feature) at the far right, and the sand dunes near Stove Pipe Wells at the center. Alluvial fans are gravel deposits that wash down from the mountains over time. Several other alluvial fans (semicircular features) can be seen along the mountain fronts in this image. The dark wrench-shaped feature between Furnace Creek fan and the dunes is a smooth flood-plain which encloses Cottonball Basin. Elevations in the valley range from 70 meters (230 feet) below sea level, the lowest in the United States, to more than 3,300 meters (10,800 feet) above sea level. Scientists are using these radar data to help answer a number of different questions about Earth's geology including how alluvial fans form and change through time in response to climatic changes and earthquakes. The image is centered at 36.629 degrees north latitude, 117.069 degrees west longitude. Colors in the image represent different radar channels as follows: red =L-band horizontally polarized transmitted, horizontally polarized received (LHH); green =L-band horizontally transmitted, vertically received (LHV) and blue = CHV.

    SIR-C/X-SAR is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground

  5. ANALYSIS OF MACROINVERTEBRATE ASSEMBLAGES IN RELATION TO ENVIRONMENTAL GRADIENTS AMONG LOTIC HABITATS OF CALIFORNIA'S CENTRAL VALLEY

    EPA Science Inventory

    We analyzed relationships between environmental characteristics and macroinvertebrate assemblages in lotic habitats of California's Central Valley with community metric and multivariate statistical approaches. Using canonical ordination analyses, we contrasted results when asse...

  6. RELATIONSHIPS BETWEEN ENVIRONMENTAL VARIABLES AND BENTHIC DIATOM ASSEMBLAGES IN CALIFORNIA CENTRAL VALLEY STREAMS (USA)

    EPA Science Inventory

    Streams and rivers in the California Central Valley Ecoregion have been substantially modified by human activities. This study examines distributional patterns of benthic diatom assemblages in relation to environmental characteristics in streams and rivers of this region. Benthic...

  7. Nitrate Contamination of Deep Aquifers in the Salinas Valley, California

    NASA Astrophysics Data System (ADS)

    Moran, J. E.; Esser, B. K.; Hillegonds, D. J.; Holtz, M.; Roberts, S. K.; Singleton, M. J.; Visser, A.; Kulongoski, J. T.; Belitz, K.

    2011-12-01

    The Salinas Valley, known as 'the salad bowl of the world', has been an agricultural center for more than 100 years. Irrigated row crops such as lettuce and strawberries dominate both land use and water use. Groundwater is the exclusive supply for both irrigation and drinking water. Some irrigation wells and most public water supply wells in the Salinas Valley are constructed to draw water from deep portions of the aquifer system, where contamination by nitrate is less likely than in the shallow portions of the aquifer system. However, a number of wells with top perforations greater than 75 m deep, screened below confining or semi-confining units, have nitrate concentrations greater than the Maximum Contaminant Limit (MCL) of 45 mg/L as NO3-. This study uses nitrate concentrations from several hundred irrigation, drinking water, and monitoring wells (Monterey County Water Resources Agency, 1997), along with tritium-helium groundwater ages acquired at Lawrence Livermore National Laboratory through the State of California Groundwater Monitoring and Assessment (GAMA) program (reported in Kulongoski et al., 2007 and in Moran et al., in press), to identify nitrate 'hot spots' in the deep aquifer and to examine possible modes of nitrate transport to the deep aquifer. In addition, observed apparent groundwater ages are compared with the results of transport simulations that use particle tracking and a stochastic-geostatistical framework to incorporate aquifer heterogeneity to determine the distribution of travel times from the water table to each well (Fogg et al., 1999). The combined evidence from nitrate, tritium, tritiogenic 3He, and radiogenic 4He concentrations, reveals complex recharge and flow to the capture zone of the deep drinking water wells. Widespread groundwater pumping for irrigation accelerates vertical groundwater flow such that high nitrate groundwater reaches some deep drinking water wells. Deeper portions of the wells often draw in water that recharged

  8. Estimating soil matric potential in Owens Valley, California

    USGS Publications Warehouse

    Sorenson, Stephen K.; Miller, R.F.; Welch, M.R.; Groeneveld, D.P.; Branson, F.A.

    1988-01-01

    Much of the floor of the Owens Valley, California, is covered with alkaline scrub and alkaline meadow plant communities, whose existence is dependent partly on precipitation and partly on water infiltrated into the rooting zone from the shallow water table. The extent to which these plant communities are capable of adapting to and surviving fluctuations in the water table depends on physiological adaptations of the plants and on the water content, matric potential characteristics of the soils. Two methods were used to estimate soil matric potential in test sites in Owens Valley. The first was the filter-paper method, which uses water content of filter papers equilibrated to water content of soil samples taken with a hand auger. The other method of estimating soil matric potential was a modeling approach based on data from this and previous investigations. These data indicate that the base 10 logarithm of soil matric potential is a linear function of gravimetric soil water content for a particular soil. Estimates of soil water characteristic curves were made at two sites by averaging the gravimetric soil water content and soil matric potential values from multiple samples at 0.1 m depths derived by using the hand auger and filter paper method and entering these values in the soil water model. The characteristic curves then were used to estimate soil matric potential from estimates of volumetric soil water content derived from neutron-probe readings. Evaluation of the modeling technique at two study sites indicated that estimates of soil matric potential within 0.5 pF units of the soil matric potential value derived by using the filter paper method could be obtained 90 to 95% of the time in soils where water content was less than field capacity. The greatest errors occurred at depths where there was a distinct transition between soils of different textures. (Lantz-PTT)

  9. Climate Impacts on Irrigated Agriculture in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Winter, J.; Young, C. A.; Mehta, V. K.; Davitt, A. W. D.; Azarderakhsh, M.; Ruane, A. C.; Rosenzweig, C.

    2015-12-01

    Irrigated farms account for 80%-90% of consumptive water use in the United States and $118.5 billion of US agricultural production. Despite the vast water use and high yields of irrigated croplands, agriculture is typically the lowest value sector in a water resources system, and thus the first to face reductions when water becomes scarce. A major challenge for hydrologic and agricultural communities is assessing the effects of climate change on the sustainability of regional water resources and irrigated agriculture. To explore the interface of water and agriculture in California's Central Valley, the Decision Support System for Agrotechnology Transfer (DSSAT) crop model was coupled to the Water Evaluation and Planning System (WEAP) water resources model, deployed over the service area of Yolo County Flood Control and Water Conservation District, and forced using both historical and future climate scenarios. This coupling brings water supply constraints to DSSAT and sophisticated agricultural water use, management, and diagnostics to WEAP. Thirty year historical (1980-2009) simulations of WEAP-DSSAT for corn, wheat, and rice were run using a spatially interpolated observational dataset, and contrasted with future simulations using climate scenarios developed by adjusting the spatially interpolated observational dataset with North American Regional Climate Change Assessment Program differences between future (2050-2069) and historical (1980-1999) regional climate model simulations of precipitation and temperature. Generally, within the Central Valley temperatures warm by approximately 2°C, precipitation remains constant, and crop water use efficiency increases. On average corn yields decrease, wheat yields increase, and rice yields remain unchanged. Potential adaptations, as well as implications for groundwater pumping, irrigation extent and method, and land use change including fallowing and switching crops, are examined.

  10. PM10 source apportionment in California's San Joaquin valley

    NASA Astrophysics Data System (ADS)

    Chow, Judith C.; Watson, John G.; Lowenthal, Douglas H.; Solomon, Paul A.; Magliano, Karen L.; Ziman, Steven D.; Willard Richards, L.

    A PM10 (particulate matter with aerodynamic diameter equal to or less than 10 μm) aerosol study was carried out at six sites in California's San Joaquin Valley (SJV) from 14 June 1988 to 9 June 1989, as part of the 1988-1989 Valley Air Quality Study (VAQS). Concentrations of PM10 and PM2.5 (particles with aerodynamic diameters equal to or less than 2.5 μm) mass, organic and elemental carbon, nitrate, sulfate, ammonium and elements were determined in 24-h aerosol samples collected at three urban (Stockton, Fresno, Bakersfield) and three non-urban (Crows Landing, Fellows, Kern Wildlife Refuge) locations during this period. The sources which contributed to ambient concentrations of PM10 were determined by applying the Chemical Mass Balance (CMB) receptor model using the source profiles determined specifically for that study area. The VAQS data indicates the federal 24-h PM10 standard of 150 μg m -3 was exceeded at four out of the six sites and for reasons which differ by season and by spatial region of influence. The annual average source contributions to the PM10 at Bakersfield, the site with the highest annual average, were 54% from primary geological material, 15% from secondary ammonium nitrate, 10% from primary motor vehicle exhaust, 8% from primary construction; the remaining 4% was unexplained. The results of the source apportionment at all sites show that geological contributions (fugitive dust from tilling, roadways and construction) are largest in summer and fall months, while secondary ammonium nitrate contributions (deriving from direct emissions of ammonia and oxides of nitrogen from agricultural activities and engine exhaust) are largest during winter months.

  11. 76 FR 30002 - Establishment of the Antelope Valley of the California High Desert Viticultural Area

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ... Antelope Valley of the California High Desert viticultural area in the Federal Register (75 FR 53877) on... western tip of the valley, is a sedimentary bed dating to the Miocene epoch (about 23 to 5 million years... granitic rock on alluvial fans and terraces. Generally, they vary in drainage, slope, elevation,...

  12. 76 FR 298 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... Valley Unified Air Pollution Control District (SJVUAPCD) portion of the California State Implementation......... 12/17/92 08/24/07 On September 17, 2007, the submittal for San Joaquin Valley Unified Air Pollution... December 13, 1994 (59 FR 64132), EPA approved into the SIP a previous version of Rule 4402, SJVUAPCD...

  13. 77 FR 12491 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ...EPA is taking direct final action to approve revisions to the Antelope Valley Air Quality Management District (AVAQMD) and San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portions of the California State Implementation Plan (SIP). These revisions concern negative declarations for volatile organic compound (VOC) and oxides of sulfur source categories for the AVAQMD and......

  14. 78 FR 53038 - Interim Final Determination to Stay and Defer Sanctions; California; San Joaquin Valley

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ..., 2011 (76 FR 69896), we published a partial approval and partial disapproval of the San Joaquin Valley... AGENCY 40 CFR Part 52 Interim Final Determination to Stay and Defer Sanctions; California; San Joaquin... imposition of highway sanctions based on a proposed approval of revisions to the San Joaquin Valley...

  15. 77 FR 65305 - Approval of Air Quality Implementation Plans; California; San Joaquin Valley Unified Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... AGENCY 40 CFR Part 52 Approval of Air Quality Implementation Plans; California; San Joaquin Valley... (SIP) revision for the San Joaquin Valley Unified Air Pollution Control District (District) portion of... detailed discussion of District Rule 2410, please refer to our proposed approval. See 77 FR 32493 (June...

  16. Model for deformation in Long Valley, California, 1980-1983

    SciTech Connect

    Rundle, J.B.; Whitcomb, J.H.

    1984-10-10

    Geodetic data collected in Long Valley, California, from 1975 through 1981 define a pattern of uplift and strain which is evidently associated with a sequence of earthquakes occuring in May 1980 and subsequent swarm activity continuing until the present. We have constructed a model to explain the deformation observed since May 1980 in terms of inflation of two subsurface magma chambers, faulting in the south most region of the caldera, and slip in the Hilton Creek fault. The most significant new feature of the model is the shallow magma chamber at 5 km depth, located a few hundred meters to the east of the Casa Diablo hot spring area. Inflation of this chamber cause stresses which show consistency with various aspects of the seismicity in the south moat of the calcers. Calculations of stress across vertical planes over the magma chambers can be used together with failure criteria to estimate the inflation volume at which the rock layers intervening between the chamber and the surface will fail by extensional fracture.

  17. To Develop an Administrative Manual for the Cooperative Education Program at Los Angeles Valley College [California].

    ERIC Educational Resources Information Center

    Lomen, Lynn D.

    This document is Part I of the Handbook on Cooperative Education at Los Angeles Valley College (California). It was designed to standardize the procedures and policies that have proven appropriate for this college. For comparative purposes, the author studied the administration of cooperative education programs at four other California community…

  18. Food and Environment. A Teachers' Resource Guide to California Valley Agriculture.

    ERIC Educational Resources Information Center

    Railton, Esther, Comp.

    Presented is a compilation of teaching resources prepared by teachers enrolled in a graduate-level environmental education course at California State University, Hayward. The emphasis of these materials is upon agriculture and related environmental practices in California's San Joaquin Valley. Following a description of course logistics are six…

  19. Estimating soil matric potential in Owens Valley, California

    USGS Publications Warehouse

    Sorenson, Stephen K.; Miller, Reuben F.; Welch, Michael R.; Groeneveld, David P.; Branson, Farrel A.

    1989-01-01

    Much of the floor of Owens Valley, California, is covered with alkaline scrub and alkaline meadow plant communities, whose existence is dependent partly on precipitation and partly on water infiltrated into the rooting zone from the shallow water table. The extent to which these plant communities are capable of adapting to and surviving fluctuations in the water table depends on physiological adaptations of the plants and on the water content, matric potential characteristics of the soils. Two methods were used to estimate soil matric potential in test sites in Owens Valley. The first, the filter-paper method, uses water content of filter papers equilibrated to water content of soil samples taken with a hand auger. The previously published calibration relations used to estimate soil matric potential from the water content of the filter papers were modified on the basis of current laboratory data. The other method of estimating soil matric potential was a modeling approach based on data from this and previous investigations. These data indicate that the base-10 logarithm of soil matric potential is a linear function of gravimetric soil water content for a particular soil. The slope and intercepts of this function vary with the texture and saturation capacity of the soil. Estimates of soil water characteristic curves were made at two sites by averaging the gravimetric soil water content and soil matric potential values from multiple samples at 0.1-m depth intervals derived by using the hand auger and filter-paper method and entering these values in the soil water model. The characteristic curves then were used to estimate soil matric potential from estimates of volumetric soil water content derived from neutron-probe readings. Evaluation of the modeling technique at two study sites indicated that estimates of soil matric potential within 0.5 pF units of the soil matric potential value derived by using the filter-paper method could be obtained 90 to 95 percent of the

  20. Space Radar Image of Long Valley, California - 3D view

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is a three-dimensional perspective view of Long Valley, California by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. This view was constructed by overlaying a color composite SIR-C image on a digital elevation map. The digital elevation map was produced using radar interferometry, a process by which radar data are acquired on different passes of the space shuttle and, which then, are compared to obtain elevation information. The data were acquired on April 13, 1994 and on October 3, 1994, during the first and second flights of the SIR-C/X-SAR radar instrument. The color composite radar image was produced by assigning red to the C-band (horizontally transmitted and vertically received) polarization; green to the C-band (vertically transmitted and received) polarization; and blue to the ratio of the two data sets. Blue areas in the image are smooth and yellow areas are rock outcrops with varying amounts of snow and vegetation. The view is looking north along the northeastern edge of the Long Valley caldera, a volcanic collapse feature created 750,000 years ago and the site of continued subsurface activity. Crowley Lake is off the image to the left. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory

  1. Space Radar Image of Long Valley, California in 3-D

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This three-dimensional perspective view of Long Valley, California was created from data taken by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar on board the space shuttle Endeavour. This image was constructed by overlaying a color composite SIR-C radar image on a digital elevation map. The digital elevation map was produced using radar interferometry, a process by which radar data are acquired on different passes of the space shuttle. The two data passes are compared to obtain elevation information. The interferometry data were acquired on April 13,1994 and on October 3, 1994, during the first and second flights of the SIR-C/X-SAR instrument. The color composite radar image was taken in October and was produced by assigning red to the C-band (horizontally transmitted and vertically received) polarization; green to the C-band (vertically transmitted and received) polarization; and blue to the ratio of the two data sets. Blue areas in the image are smooth and yellow areas are rock outcrops with varying amounts of snow and vegetation. The view is looking north along the northeastern edge of the Long Valley caldera, a volcanic collapse feature created 750,000 years ago and the site of continued subsurface activity. Crowley Lake is the large dark feature in the foreground. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are

  2. Gravity survey and depth to bedrock in Carson Valley, Nevada-California

    USGS Publications Warehouse

    Maurer, D.K.

    1985-01-01

    Gravity data were obtained from 460 stations in Carson Valley, Nevada and California. The data have been interpreted to obtain a map of approximate depth to bedrock for use in a ground-water model of the valley. This map delineates the shape of the alluvium-filled basin and shows that the maximum depth to bedrock exceeds 5,000 feet, on the west side of the valley. A north-south trending offset in the bedrock surface shows that the Carson-Valley/Pine-Nut-Mountain block has not been tilted to the west as a simple unit, but is comprised of several smaller blocks. (USGS)

  3. The hydrothermal system of Long Valley Caldera, California

    USGS Publications Warehouse

    Sorey, M.L.; Lewis, Robert Edward; Olmsted, F.H.

    1978-01-01

    Long Valley caldera, an elliptical depression covering 450 km 2 on the eastern front of the Sierra Nevada in east-central California, contains a hot-water convection system with numerous hot springs and measured and estimated aquifer temperatures at depths of 180?C to 280?C. In this study we have synthesized the results of previous geologic, geophysical, geochemical, and hydrologic investigations of the Long Valley area to develop a generalized conceptual and mathematical model which describes the gross features of heat and fluid flow in the hydrothermal system. Cenozoic volcanism in the Long Valley region began about 3.2 m.y. (million years) ago and has continued intermittently until the present time. The major event that resulted in the formation of the Long Valley caldera took place about 0.7 m.y. ago with the eruption of 600 km 3 or more of Bishop Tuff of Pleistocene age, a rhyolitic ash flow, and subsequent collapse of the roof of the magma chamber along one or more steeply inclined ring fractures. Subsequent intracaldera volcanism and uplift of the west-central part of the caldera floor formed a subcircular resurgent dome about 10 km in diameter surrounded by a moat containing rhyolitic, rhyodacitic, and basaltic rocks ranging in age from 0.5 to 0.05 m.y. On the basis of gravity and seismic studies, we estimate an aver- age thickness of fill of 2.4 km above the precaldera granitic and metamorphic basement rocks. A continuous layer of densely welded Bishop Tuff overlies the basement rocks, with an average thickness of 1.4 km; the fill above the welded Bishop Tuff consists of intercalated volcanic flows and tuffs and fluvial and lacustrine deposits. Assuming the average grain density of the fill is between 2.45 and 2.65 g/cm 3 , we calculate the average bulk porosity of the total fill as from 0.11 to 0.21. Comparison of published values of porosity of the welded Bishop Tuff exposed southeast of the caldera with calculated values indicates average bulk porosity

  4. Particulate carbon measurements in California's San Joaquin Valley.

    PubMed

    Chow, Judith C; Watson, John G; Lowenthal, Douglas H; Chen, L-W Antony; Magliano, Karen L

    2006-01-01

    Aerosol carbon sampling methods and biases were evaluated during the California Regional PM10/PM2.5 Air Quality Study (CRPAQS) and Fresno Supersite programs. PM2.5 sampling was conducted using Desert Research Institute (DRI) sequential filter samplers (SFS) from December 1999 through February 2001 at two urban sites (Fresno and Bakersfield), one regional transport site (Angiola), and two boundary sites (Bethel Island and Sierra Nevada Foothills) during CRPAQS in the San Joaquin Valley (SJV). Additional filter-based sampling was done in Fresno as part of the US Environmental Protection Agency (EPA) Supersites program. Organic carbon (OC) and elemental carbon (EC) concentrations were higher during winter (December-February) than summer (June-August) and this trend was most pronounced at Fresno and Bakersfield. OC and EC displayed similar diurnal trends during winter and summer at Fresno and during winter at Angiola. The diurnal pattern at Angiola reflected the transport of secondary pollutants to the site. Collocated measurements of OC and EC on undenuded quartz-fiber filters were made at Fresno with the DRI SFS and the Andersen FRM and RAAS samplers. All average differences in OC between samplers were less than their respective measurement uncertainties. Positive and negative OC biases were evaluated at Fresno using the Andersen RAAS sampler with carbon-denuded and undenuded channels with Teflon-membrane and quartz-fiber filter pairs. Differences between the denuded particle OC and that obtained by subtracting the quartz-behind-Teflon or quartz-behind-quartz OC from the undenuded quartz-fiber front filter were less than twice their measurement uncertainties in most cases. Particulate OC in the denuded channel agreed most closely with the difference between undenuded front and backup quartz-fiber OC. PMID:15990153

  5. Identifying Key Vulnerabilities in Current Management of California Central Valley for the California Water Plan

    NASA Astrophysics Data System (ADS)

    Bloom, E.; Groves, D.; Joyce, B. A.; Juricich, R.

    2012-12-01

    The California Department of Water Resources (DWR), for its 2013 Update of the California Water Plan (CWP), is building new analytic capabilities for developing and evaluating regional and state-wide water management strategies. These strategies are intended to address growing and diverse water needs coupled with uncertain future hydrologic conditions and available supplies. Recognizing the significant uncertainty about future water management conditions, DWR is utilizing new robust decision methods to identify robust and adaptive water management strategies. This talk will describe a recently completed application of Robust Decision Making (RDM) for long-term water planning as part of the 2013 CWP Update. This analysis utilizes a new hydrologic / water management model of the Sacramento River, San Joaquin River, and Tulare hydrologic regions, running the model under hundreds of potential futures. These futures consider potential variation in demographic growth, land-use patterns, drought length and timing, and other climate factors from projections generated by downscaled global circulation models. Cluster-finding "scenario discovery" algorithms, applied to the resulting database of simulation model results, identify the key characteristics of future conditions where current management fails to meet a wide range of policy objectives. These "vulnerabilities" provide the foundation for developing more robust and adaptive response packages and the considering tradeoffs between such response packages. This analysis will provide guidance for considering response packages to meet the challenges posed by future conditions in the California Central Valley and provides a widely applicable new approach for making water management plans more cognizant and responsive to a wide range of uncertainties.

  6. Spatio-temporal evolution of aseismic ground deformation in the Mexicali Valley (Baja California, Mexico) from 1993 to 2010, using differential SAR interferometry

    NASA Astrophysics Data System (ADS)

    Sarychikhina, O.; Glowacka, E.

    2015-11-01

    Ground deformation in Mexicali Valley, Baja California, Mexico, the southern part of the Mexicali-Imperial valley, is influenced by active tectonics and human activity, mainly that of geothermal fluid extraction in the Cerro Prieto Geothermal Field. Significant ground deformation, mainly subsidence (~ 18 cm yr-1), and related ground fissures cause severe damage to local infrastructure. The technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) has been demonstrated to be a very effective remote sensing tool for accurately measuring the spatial and temporal evolution of ground displacements over broad areas. In present study ERS-1/2 SAR and ENVISAT ASAR images acquired between 1993 and 2010 were used to perform a historical analysis of aseismic ground deformation in Mexicali Valley, in an attempt to evaluate its spatio-temporal evolution and improve the understanding of its dynamic. For this purpose, the conventional 2-pass DInSAR was used to generate interferograms which were used in stacking procedure to produce maps of annual aseismic ground deformation rates for different periods. Differential interferograms that included strong co-seismic deformation signals were not included in the stacking and analysis. The changes in the ground deformation pattern and rate were identified. The main changes occur between 2000 and 2005 and include increasing deformation rate in the recharge zone and decreasing deformation rate in the western part of the CPGF production zone. We suggested that these changes are mainly caused by production development in the Cerro Prieto Geothermal Field.

  7. 3-D Velocity Model of the Coachella Valley, Southern California Based on Explosive Shots from the Salton Seismic Imaging Project

    NASA Astrophysics Data System (ADS)

    Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.

    2014-12-01

    of the largest earthquakes in the 2012 Brawley swarm, Imperial Valley, California: Geophysical Research Letters, v. 40, no. 5, p. 847-852.

  8. Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

    USGS Publications Warehouse

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2010-01-01

    This report summarizes comprehensive findings from a 4-year-long field investigation to document baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water-quality collections and fish community assessments were conducted on as many as 16 sampling dates at roughly quarterly intervals from July 2005 to April 2009. The water-quality measurements included total suspended solids and total (particulate plus dissolved) selenium. With one exception, fish were surveyed with baited minnow traps at quarterly intervals during the same time period. However, in July 2007, fish surveys were not conducted because we lacked permission from the California Department of Fish and Game for incidental take of desert pupfish (Cyprinodon macularius), an endangered species. During April and October 2006-08, water samples also were collected from seven intensively monitored drains (which were selected from the 29 total drains) for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices [particulate organic detritus, filamentous algae, net plankton, and midge (chironomid) larvae], and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for pupfish, which we were not permitted to sacrifice for selenium determinations. Water quality (temperature, dissolved oxygen, pH, specific conductance, and turbidity) values were typical of surface waters in a hot, arid climate. A few drains exhibited brackish, near-anoxic conditions, especially during summer and fall when water temperatures occasionally exceeded 30 degrees Celsius. Total selenium concentrations in water were directly correlated with salinity and

  9. Space Radar Image of Long Valley, California -Interferometry/Topography

    NASA Technical Reports Server (NTRS)

    1994-01-01

    These four images of the Long Valley region of east-central California illustrate the steps required to produced three dimensional data and topographics maps from radar interferometry. All data displayed in these images were acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour during its two flights in April and October, 1994. The image in the upper left shows L-band (horizontally transmitted and received) SIR-C radar image data for an area 34 by 59 kilometers (21 by 37 miles). North is toward the upper right; the radar illumination is from the top of the image. The bright areas are hilly regions that contain exposed bedrock and pine forest. The darker gray areas are the relatively smooth, sparsely vegetated valley floors. The dark irregular patch near the lower left is Lake Crowley. The curving ridge that runs across the center of the image from top to bottom is the northeast rim of the Long Valley Caldera, a remnant crater from a massive volcanic eruption that occurred about 750,000 years ago. The image in the upper right is an interferogram of the same area, made by combining SIR-C L-band data from the April and October flights. The colors in this image represent the difference in the phase of the radar echoes obtained on the two flights. Variations in the phase difference are caused by elevation differences. Formation of continuous bands of phase differences, known as interferometric 'fringes', is only possible if the two observations were acquired from nearly the same position in space. For these April and October data takes, the shuttle tracks were less than 100 meters (328 feet) apart. The image in the lower left shows a topographic map derived from the interferometric data. The colors represent increments of elevation, as do the thin black contour lines, which are spaced at 50-meter (164-foot) elevation intervals. Heavy contour lines show 250-meter intervals (820-foot). Total relief in

  10. 75 FR 44278 - Notice of Availability of the Final Environmental Impact Statement for the Imperial Valley Solar...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-28

    ...: Stirling Energy Systems (SES) filed right- of-way (ROW) application CACA-47740 for the SES Solar Two... mirror facets. These mirrors concentrate solar energy onto the solar receiver of the PCU. The project... into a MOU with the California Energy Commission (CEC) to conduct a joint environmental review of...

  11. Geothermal systems of the Mono Basin-Long Valley region, eastern California and western Nevada

    SciTech Connect

    Higgins, C.T.; Flynn, T.; Chapman, R.H.; Trexler, D.T.; Chase, G.R.; Bacon, C.F.; Ghusn, G. Jr.

    1985-01-01

    The region that includes Mono Basin, Long Valley, the Bridgeport-Bodie Hills area, and Aurora, in eastern California and western Nevada was studied to determine the possible causes and interactions of the geothermal anomalies in the Mono Basin-Long Valley region as a whole. A special goal of the study was to locate possible shallow bodies of magma and to determine their influence on the hydrothermal systems in the region. (ACR)

  12. Rare earth element content of thermal fluids from Surprise Valley, California

    DOE Data Explorer

    Andrew Fowler

    2015-09-23

    Rare earth element measurements for thermal fluids from Surprise Valley, California. Samples were collected in acid washed HDPE bottles and acidified with concentrated trace element clean (Fisher Scientific) nitric acid. Samples were pre-concentratated by a factor of approximately 10 using chelating resin with and IDA functional group and measured on magnetic sector ICP-MS. Samples include Seyferth Hot Springs, Surprise Valley Resort Mineral Well, Leonard's Hot Spring, and Lake City Mud Volcano Boiling Spring.

  13. Irrigation in California's Central Valley Strengthens the Southwestern U. S. Monsoon

    NASA Astrophysics Data System (ADS)

    Lo, M.; Famiglietti, J. S.

    2011-12-01

    Agricultural irrigation in the Central Valley of California has always depended on surface water reservoirs and groundwater pumping. This anthropogenic redistribution of water modifies the land hydrological cycle significantly, especially by increasing evapotranspiration. In this study we establish the importance of California's Central Valley irrigation in the local and regional hydrological cycles, including its role in land surface-atmosphere interactions. We use the global, NCAR Community Atmosphere Model, with realistic estimates of irrigation applied to the NCAR Community Land Model. Consistent with previous studies, we find that irrigation modifies the surface radiation budget by generally increasing latent heat, decreasing sensible heat and decreasing land surface temperature. Although atmospheric water vapor increases due to enhanced evapotranspiration, during the summer, the Central Valley underlies the descending branch of the large-scale circulation, which inhibits the occurrence of convection. Consequently, Central Valley irrigation has negligible effects on local precipitation. However, precipitation in the downwind region of California, i.e., in the southwestern U. S., increases, enhancing the North American Monsoon, while forming a regional, anthropogenic recycling loop in the hydrologic cycle which returns water to California. This study has implications for the importance of human-driven impacts on the hydrological cycle and local and regional climate, and for water resources management in California and the Western United States.

  14. Diurnal Evolution of Three-Dimensional Wind and Temperature Structure in California's Central Valley

    SciTech Connect

    Zhong, Shiyuan; Whiteman, Charles D.; Bian, Xindi

    2004-11-01

    The diurnal evolution of the three-dimensional summer season mean wind and temperature structure in California’s Sacramento and San Joaquin Valleys (collectively called the Central Valley) are investigated using data from 22 radar wind profiler/Radio Acoustic Sounding Systems (RASS) operated as part of the Central California Ozone Study in 2000. The profiler network revealed, for the first time, that the persistent summer season flow pattern documented by surface observations extends 800-1000 m above the surface. At most locations, up-valley winds persist both day and night except at the upper ends of the valleys and close to the valley sidewalls where diurnal wind reversals occur. Wind speeds exhibit pronounced diurnal oscillations, with amplitudes decreasing with height. A low-level wind maximum occurs in the lowest 300 m, with a sharp decrease in speed above the maximum. Especially well-defined nocturnal low-level jets occur at sites in the southern San Joaquin Valley, where maximum speeds of 10 m s-1 or more occur 1-2 h before midnight at heights near 300 m. The afternoon mixed layer, generally deeper than 1000 m, increases in depth with up-valley distance in both valleys. At night, temperature inversions develop in the lowest several hundred meters with near-isothermal layers above. Mean temperatures in the lowest 500 m of the valleys are always warmer than at the same altitude over the coast, and temperature increases from the lower to upper valleys. The diurnal oscillation of the coast-valley and along-valley temperature and pressure difference reach a maximum in late afternoon and a minimum in early morning. These oscillations are in phase with the diurnal variation of westerly onshore flows. The along-valley wind maxima, however, occur 1-2 h before midnight while the pressure gradient maxima are usually found just before sunset.

  15. Quantitative rock-fall hazard and risk assessment for Yosemite Valley, Yosemite National Park, California

    USGS Publications Warehouse

    Stock, Greg M.; Luco, Nicolas; Collins, Brian D.; Harp, Edwin L.; Reichenbach, Paola; Frankel, Kurt L.

    2014-01-01

    Rock falls are common in Yosemite Valley, California, posing substantial hazard and risk to the approximately four million annual visitors to Yosemite National Park. Rock falls in Yosemite Valley over the past few decades have damaged structures and caused injuries within developed regions located on or adjacent to talus slopes highlighting the need for additional investigations into rock-fall hazard and risk. This assessment builds upon previous investigations of rock-fall hazard and risk in Yosemite Valley and focuses on hazard and risk to structures posed by relatively frequent fragmental-type rock falls as large as approximately 100,000 (cubic meters) in volume.

  16. Water-level changes (1975-1998) in the Antelope Valley ground-water basin, California

    USGS Publications Warehouse

    Carlson, Carl S.; Phillips, Steven P.

    1998-01-01

    Antelope Valley is in the western part of the Mojave Desert in southern California, about 50 mi northeast of Los Angeles. Between 1975 and 1998, water levels in the valley have changed in response to a shift in ground-water use from agricultural to urban, declining in some areas and rising in others. A study to document these changes was conducted by the U.S. Geological Survey in cooperation with the Antelope Valley Water Group. This report presents the water-level data and the changes that occurred during this study period.

  17. HCMM: Soil moisture in relation to geologic structure and lithology, northern California. [Sacramento Valley, California

    NASA Technical Reports Server (NTRS)

    Rich, E. I. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. Empirical observations on the ground and examination of aerial color IR photographs indicate that in grassland terrain, the vegetation overlying sandstone tends to become less vigorous sooner in the late spring season than does the area overlain by an adjacent shale unit. The reverse relationship obtains in the fall. These relationships are thought to be a reflection of the relative porosity of each of the units and hence of their ability to retain or lose soil moisture. A comparison of the optically enlarged day and nite IR imagery of the Late Mesozoic interbedded sandstone and shale units along the western margin of the Sacramento Valley, California, taken at seasonally critical times of the year (late spring/early summer and late fall/early winter) reveals subtle seasonal variations of graytone which tend to support the empirical observations after consideration of Sun angle and azimuth, and the internal consistency of the data on each set of satellite imagery.

  18. Late Cenozoic tectonism of the Sacramento Valley, California

    SciTech Connect

    Harwood, D.S.; Helley, E.J.

    1987-01-01

    Structure contours drawn on top of the Cretaceous rocks in the Sacramento Valley define a large number of diversely oriented folds and faults that are expressed in topographic, hydrologic, and geologic features at the land surface. Although many of the structures in the valley have a protracted history of movement, some dating back to the late Mesozoic, a remarkable number of these structures show late Cenozoic deformation that can be accurately determined from folding and faulting of widespread, dated Pliocene and Pleistocene volcanic units. These time-stratigraphic units are used to define structural domains of essentially contemporaneous late Cenozoic deformation that was characterized by east-west compressive stress. The oldest structural domain is located in the southeastern part of the valley, where east-side-up reverse movement on the Willows fault ceased prior to deposition of continentally derived sediments of late Miocene and early Pliocene age. In the middle Pliocene to early Pleistocene, east-west compressive deformation progressed northward through the valley so that the youngest late Cenozoic deformation is recorded in east-northeast-trending folds and faults in the Battle Creek domain, at the northern-most part of the valley. The northward progression of east-west compressive deformation appears to be related to the northward eclipse of eastward subduction of the Juan de Fuca plate before the northwestward migration of the Mendocino triple junction along the continental margin west of the valley.

  19. Growing more with less in the Westlands Water District in the San Joaquin Valley, California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disposal of saline drainage water is a problem for irrigated agricultural throughout the world. In California the Westlands Water District in the San Joaquin Valley had its drainage service eliminated because of selenium contamination in the Kesterson Reservoir. A five-year study developed alternati...

  20. Pesticide Risk Communication, Risk Perception, and Self-Protective Behaviors among Farmworkers in California's Salinas Valley

    ERIC Educational Resources Information Center

    Cabrera, Nolan L.; Leckie, James O.

    2009-01-01

    Agricultural pesticide use is the highest of any industry, yet there is little research evaluating farmworkers' understandings of the health risks chemical exposure poses. This study examines pesticide education, risk perception, and self-protective behaviors among farmworkers in California's Salinas Valley. Fifty current and former farmworkers…

  1. Development of Biological and Cultural Control of Olive Fruit Fly in the Central Valley of California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The eastern side of the Central Valley of California where olives are grown for canning was surveyed for olive fruit fly, Bactrocera oleae (Rossi), infestations. The pest was found for the first time in unusually high numbers in Merced. The a parasitic wasp, Psyttalia humilis (Silvestri), was import...

  2. Communication/Culture Study for Victor Valley College, Victorville, California, November 1991-April 1992.

    ERIC Educational Resources Information Center

    Caldwell, Patricia F.

    In November 1991, a study was conducted to assess the corporate culture and state of communication at Victor Valley College (VVC), in Victorville, California. The study was designed to determine the extent to which "trust" or "distrust" existed at VVC, and whether the lack of communication on campus was real or perceived. Study methodology…

  3. 76 FR 56132 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-12

    ...EPA is proposing to approve revisions to the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) portion of the California State Implementation Plan (SIP). These revisions concern volatile organic compound (VOC) emissions from polyester resin operations. We are approving a local rule that regulates these emission sources under the Clean Air Act as amended in 1990 (CAA or the......

  4. Epidemiology of almond leaf scorch disease in the San Joaquin Valley of California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almond leaf scorch (ALS) disease has been present in California for more than 60 years. This disease is caused by the bacterium Xylella fastidiosa, which causes several other important plant diseases, including Pierce’s disease of grapes. The epidemiology of ALS in the San Joaquin Valley of Califo...

  5. Isotopic evidence for climatic influence on alluvial-fan development in Death Valley, California

    SciTech Connect

    Dorn, R.I.; DeNiro, M.J.; Ajie, H.O.

    1987-02-01

    At least three semiarid to arid cycles are recorded by ..delta../sup 13/C values of organic matter in layers of rock varnishes on surfaces of Hanaupah Canyon and Johnson Canyon alluvial fans, Death Valley, California. These isotopic paleoenvironmental signals are interpreted as indicating major periods of fan aggradation during relatively more humid periods and fan entrenchment during subsequent lengthy arid periods.

  6. 76 FR 16696 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-25

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control... November 5, 2010 (75 FR 68294), EPA proposed to approve the following rule into the California SIP....

  7. 76 FR 69135 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-08

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control... 16, 2011 (76 FR 35167), EPA proposed to approve the following rule into the California SIP....

  8. 76 FR 68103 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control... Action On June 30, 2011 (76 FR 38340), EPA proposed to approve the following rule into the California...

  9. 76 FR 53640 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-29

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control... Action On June 24, 2011 (76 FR 37044), EPA proposed to approve the following rule into the California...

  10. 75 FR 60623 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-01

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule... Valley Unified Air Pollution Control District (SJVUAPCD) portion of the California State Implementation.... Proposed Action On 12/09/09 (74 FR 65042), EPA proposed a limited approval and limited disapproval of...

  11. 75 FR 2796 - Revisions to the California State Implementation Plan, San Joaquin Valley Air Pollution Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... is finalizing approval of revisions to the San Joaquin Valley Air Pollution Control District portion... On June 16, 2009 (74 FR 28467), EPA proposed to approve the following rules into the California SIP... topcoats; and that Ventura County Air Pollution Control District's (VCAPCD) rule has more stringent...

  12. 76 FR 47076 - Revision to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-04

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of a revision to the San Joaquin Valley Unified Air Pollution Control... Action On June 8, 2011 (76 FR 33181), EPA proposed to approve the following rule into the California...

  13. 77 FR 745 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-06

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) Correction In rule document 2011-33660 appearing on...

  14. 77 FR 214 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-04

    ... Air Pollution Control District (SJVUAPCD) AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Air Pollution Control... Action On July 11, 2011 (76 FR 132), EPA proposed to approve the following rules into the California...

  15. 75 FR 1716 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-13

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule... Valley Unified Air Pollution Control District (SJVUAPCD) portion of the California State Implementation... Reviews I. Proposed Action On August 19, 2009 (74 FR 41826), EPA proposed a limited approval and...

  16. 77 FR 64427 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control... June 13, 2012 (77 FR 35329), EPA proposed to approve the following rules into the California SIP....

  17. 78 FR 6740 - Revisions to the California State Implementation Plan, San Joaquin Valley United Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-31

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley United Air Pollution Control... FR 66429), EPA proposed to approve the following rule into the California SIP. Local agency Rule...

  18. 75 FR 24408 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is finalizing approval of revisions to the San Joaquin Valley Unified Air Pollution Control... FR 3680), EPA proposed to approve the following rule into the California SIP. Rule Rule title...

  19. Data from geothermal gradient wells near Oasis, lower Coachella Valley, California

    USGS Publications Warehouse

    Robison, J.H.

    1981-01-01

    This report includes drillers ' logs, temperature logs, and water quality analyses from geothermal tests made at 11 sites near Oasis, lower Coachella Valley, California. A map shows the locations of the wells and also included is the location-numbering system for wells. (USGS)

  20. 77 FR 12651 - Approval of Air Quality Implementation Plans; California; San Joaquin Valley; Attainment Plan for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ... standards (NAAQS) in the San Joaquin Valley (SJV). See 76 FR 57846. California developed this SIP to provide... implementation rule.\\1\\ \\1\\ See 40 CFR part 51, subpart X and 69 FR 23951 (April 30, 2004) and 70 FR 71612... and reductions by the District and CARB.\\4\\ 76 FR 57846, 57867. \\3\\ See letter, James...

  1. Epidemiology of xylellae diseases in the San Joaquin Valley of California: the role of alfalfa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pierce’s disease of grape and almond leaf scorch disease are both caused by various stains of the bacterial pathogen Xylella fastidiosa. The pathogen is vectored by xylem feeding insects. Within the San Joaquin Valley of California, the green sharpshooter (Draeculacephala Minerva) is one of the mos...

  2. 75 FR 39581 - Yosemite Valley Plan; Yosemite National Park; Mariposa, Madera, and Tuolumne Counties, California...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR National Park Service Yosemite Valley Plan; Yosemite National Park; Mariposa, Madera, and Tuolumne Counties, California; Notice of Revised Record of Decision SUMMARY: On December 29, 2000, the National Park...

  3. To Develop a Curriculum Manual for the Cooperative Education Program at Los Angeles Valley College [California].

    ERIC Educational Resources Information Center

    Lomen, Lynn D.

    This document is Part II of the Handbook on Cooperative Education at Los Angeles Valley College (California). It was designed to enable instructor/coordinators to conduct classes more effectively and efficiently. Outlines are provided of the new and revised curriculum offerings that have been suggested by students, the Cooperative Education…

  4. 77 FR 58078 - Withdrawal of Approval of Air Quality Implementation Plans; California; San Joaquin Valley; 1...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-19

    ... San Joaquin Valley (SJV) extreme ozone nonattainment area. 75 FR 10420. The California Air Resources... the 1-hour ozone NAAQS effective May 17, 2004. 69 FR 20550 (April 16, 2004).\\1\\ The SIP revisions that...-hour ozone standard in the SJV area. See 75 FR 10420, 10421 (March 8, 2010). \\1\\ EPA established a...

  5. Comparison of inversion models using AIRSAR data for Death Valley, California

    NASA Technical Reports Server (NTRS)

    Kierein-Young, Kathryn S.

    1993-01-01

    Polarimetric Airborne Synthetic Aperture Radar (AIRSAR) data were collected for the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley, California, USA, in September 1989. AIRSAR is a four-look, quid-polarizaiton, three frequency instrument. It collects measurements at C-band (5.66 cm), L-band (23.98 cm), and P-band (68.13 cm), and has a GIFOV of 10 meters and a swath width of 12 kilometers. Because the radar measures at three wavelengths, different scales of surface roughness are measured. Also, dielectric constants can be calculated from the data. The scene used in this study is in Death Valley, California and is located over Trail Canyon alluvial fan, the valley floor, and Artists Drive alluvial fan. The fans are very different in mineralogic makeup, size, and surface roughness. Trail Canyon fan is located on the west side of the valley at the base of the Panamint Range and is a large fan with older areas of desert pavement and younger active channels. The source for the material on southern part of the fan is mostly quartzites and there is an area of carbonate source on the northern part of the fan. Artists Drive fan is located at the base of the Black Mountains on the east side of the valley and is a smaller, young fan with its source mostly from volcanic rocks. The valley floor contains playa and salt deposits that range from smooth to Devil's Golf course type salt pinnacles.

  6. Geophysical Investigations of Structures within Southern Fish Lake Valley, California

    NASA Astrophysics Data System (ADS)

    McBride, K.; Ferguson, J. F.; Oldow, J. S.

    2015-12-01

    The 80km Fish Lake Valley Fault Zone makes up the northern portion of the Furnace Creek - Death Valley Fault Zone, a 250km right lateral oblique strike slip system that accounts for up to 25% of the relative motion between the Pacific and North American Plates. The Cucomongo Canyon Restraining bend lies to the south of Fish Lake Valley, and causes localized uplift. The developmental history of the Cucomongo Canyon restraining bend and the resultant uplift, deformation, and displacement is the focus of an integrated study by the Miles Geoscience Center at the University of Texas at Dallas. This specific part of the study focuses on the southernmost section of Fish Lake Valley, where Paleozoic sedimentary rocks are juxtaposed with Cenozoic sediments on multiple faulted boundaries. Structural constraints are not very well known as the faults are locally obscured by Quaternary alluvial deposits of various ages. Analysis of high resolution topography, produced from LiDAR scanning performed by the Miles team, and imagery shows subtle geomorphic expressions related to faulting. A near surface geophysical survey utilizing high resolution seismic refraction and microGal gravity measurements was done to explore the subsurface beneath the alluvium. Forward models were created to identify faults and ascertain vertical offsets and orientations. The geophysical models indicate a zone of extensional deformation north of the restraining bend

  7. Urban hydrology in the desert, Antelope Valley, California

    USGS Publications Warehouse

    Blodgett, James C.; Nasseri, Iraj; Elliott, Ann L.

    1990-01-01

    A study of urban hydrology in Antelope Valley includes data collection, analysis of rainfall and runoff frequencies, and comparison of results from various rainfall-runoff models. This paper discusses only parts of the project that include data collection and frequency analyses.

  8. Hydrology of modern and late Holocene lakes, Death Valley, California

    SciTech Connect

    Grasso, D.N.

    1996-07-01

    Above-normal precipitation and surface-water runoff, which have been generally related to the cyclic recurrence of the El Nino-Southern Oscillation, have produced modern ephemeral lakes in the closed-basin Death Valley watershed. This study evaluates the regional hydroclimatic relations between precipitation, runoff, and lake transgressions in the Death Valley watershed. Recorded precipitation, runoff, and spring discharge data for the region are used in conjunction with a closed-basin, lake-water-budget equation to assess the relative contributions of water from these sources to modern lakes in Death Valley and to identify the requisite hydroclimatic changes for a late Holocene perennial lake in the valley. As part of the Yucca Mountain Site Characterization Program, an evaluation of the Quaternary regional paleoflood hydrology of the potential nuclear-waste repository site at Yucca Mountain, Nevada, was planned. The objectives of the evaluation were (1) to identify the locations and investigate the hydraulic characteristics of paleofloods and compare these with the locations and characteristics of modern floods, and (2) to evaluate the character and severity of past floods and debris flows to ascertain the potential future hazards to the potential repository during the pre-closure period (US Department of Energy, 1988). This study addresses the first of these objectives, and the second in part, by assessing and comparing the sizes, locations, and recurrence rates of modern, recorded (1962--83) floods and late Holocene paleofloods for the 8,533-mi{sup 2}, closed-basin, Death Valley watershed with its contributing drainage basins in the Yucca Mountain site area.

  9. DEFORMATION NEAR THE EPICENTER OF THE 1984 ROUND VALLEY, CALIFORNIA, EARTHQUAKE.

    USGS Publications Warehouse

    Gross, W.K.; Savage, J.C.

    1985-01-01

    A trilateration network extending from near Mammoth Lakes to Bishop, California, was resurveyed following the November 23, 1984, Round Valley earthquake (M//L equals 5. 8). The network had previously been surveyed in 1982. Deformation apparently associated with the Round Valley earthquake was detected as well as deformation due to the expansion of a magma chamber 8 km beneath the resurgent dome in the Long Valley caldera and right-lateral slip on the uppermost 2 km of the 1983 rupture surface in the south moat of the caldera. The deformation associated with Round Valley earthquake suggests left-lateral slip on the north-northeasterly striking vertical plane defined by the aftershock hypocenters. (Edted author abstract) Refs.

  10. Ground-water conditions and potential for artificial recharge in Lucerne Valley, San Bernardino County, California

    USGS Publications Warehouse

    Schaefer, Donald H.

    1979-01-01

    The water level in two areas of Lucerne Valley in California has declined more than 100 feet since 1917, including 60 feet from 1954 to 1976. These declines are the result of pumping for the irrigation of alfalfa. The lowering of water levels has caused many shallow domestic wells to go dry. Well yields in the valley generally are between 10 and 1,000 gallons per minute. About 240 ,000 acre-feet of ground water was withdrawn between 1950 and 1976. About 1,750,000 acre-feet remains in storage. Water of poor quality underlies the valley around Lucerne Lake. There was no definable movement of this water from 1954 to 1976, but the possibility exists for future movement toward centers of pumping. Lucerne Valley may be hydrologically suitable for artificial-recharge operations. (Woodard-USGS)

  11. Short-term reproductive diapause by Culex tarsalis (Diptera: Culicidae) in the Coachella Valley of California.

    PubMed

    Reisen, W K; Smith, P T; Lothrop, H D

    1995-09-01

    Culex tarsalis Coquillett from the Coachella Valley in southeastern California enter a short-term reproductive diapause that is terminated by changes in photoperiod at or shortly after the winter solstice. Reproductively active and unfed resting females exhibited respective increases and decreases in parity rates during December that were characteristic of diapause induction, although reproductively active females, larvae, and males were collected during every month throughout winter. Laboratory experiments demonstrated that females from Coachella Valley enter and maintain a facultative reproductive diapause similar to females from the more northern San Joaquin Valley when exposed to simulated winter conditions. In environmental chambers, diapause termination was not related to temperature accrual because females terminated diapause at approximately the same time regardless of temperature regimens. A field experiment showed that female cohorts emerging in the Coachella Valley from late October through December entered a reproductive diapause that was terminated synchronously by changing photoperiod in late December. PMID:7473621

  12. Digital-model evaluation of the ground-water resources in Ocotillo-Coyote Wells Basin, Imperial County, California

    USGS Publications Warehouse

    Skrivan, James A.

    1977-01-01

    A flow model using finite-element techniques has been constructed for an alluvial aquifer in the Ocotillo-Coyote Wells Basin, Imperial County, Calif. Natural recharge is about 2,600 acre-feet per year, and estimated ground water in storage is 640 ,000 acre-feet. Pumpage totaled 880 acre-feet in 1975. The computed decline from steady-state conditions in 1925 to December 1975 was 15 feet in Ocotillo. The projected decline from 1976 to 1995 with annual pumpage of 1,000 acre-feet is 6 feet and with annual pumpage of 2,000 acre-feet is 17 feet in Ocotillo. In the latter projection, continued pumping after 1995 may cause saline water to flow toward the potable ground water in and around Ocotillo. (Woodard-USGS)

  13. Sedimentary facies of alluvial fan deposits, Death Valley, California

    SciTech Connect

    Middleton, G.V. )

    1992-01-01

    Fans in Death Valley include both diamicts and bedded gravels. Seven facies may be recognized. The diamicts include: (1) matrix-rich, coarse wackestones; (2) thin, matrix-rich, fine wackestones, that may show grading; (3) matrix-poor, coarse packstones, transitional to wackestones. The bedded facies include: (4) weakly bedded, poorly sorted packstones or grainstones, that show patchy imbrication, and cut-and-fill structures; (5) packed, imbricated cobble lenses, generally interbedded in facies 4; (6) distinctly bedded gravels, that are better bedded, finer and better sorted, and show better imbrication than facies 4, but still do not show clear separation of sand and gravel beds; (7) backfill cross-bedded gravels. Sand beds are not seen in fan deposits. Sand is present in eolian deposits, as plane-laminated, back-eddy deposits in Death Valley Wash, and as laminated or rippled sand in the Amargosa River. The most remarkable features of the fan deposits are the very weak segregation of sand and gravel, and the complete absence of any lower flow-regime structures produced by ripples or dunes. During floods, the slope of fan and even large wash surfaces is steep enough to produce upper flow regimes. There are also very few trends in facies abundance down fans: most fans in Death Valley itself are not strongly dominated by debris flow deposits (diamicts). The facies characteristics of a given fan vary little from proximal to distal regions, but may differ strongly from the facies seen in adjacent fans. Ancient deposits that show clear segregation of gravel from cross-bedded sand beds, or strong proximal to distal facies transitions, must have been deposited in environments quite different from Death Valley.

  14. Tectonic tilting of the northern Owens Valley, California

    SciTech Connect

    Pinter, N.; Keller, E.A. . Dept. of Geological Sciences)

    1992-01-01

    Tectonic rotation is characteristic of active deformation in many of the structural basins of the Basin and Range. The Owens Valley (OV) is the most western basin of the province. The structure, stratigraphy, and geomorphology of the northern OV suggest that there has been active eastward tilting of the valley throughout at least the late Quaternary. A series of analytical techniques are developed here which quantify the age, rate, and character of deformation. The geomorphic clock'' of the northern OV was reset 738,000 years ago by the unroofing of Long Valley Caldera, just to the north, and the emplacement of the Bishop Tuff ignimbrite sheet. Since that time, cooling joints in the tuff and channels cut into the surface of the sheet have been reoriented, and fluvial terraces and alluvial fans have been tilted. Each of these analyses have the same solution--a net down-to-the-east rotation of the valley block at a mean rate of 0.8--1.0[degree]/Ma. Other indicators of tilt support this solution: fluvial and lacustrine strata at the type-locality of the Glass Mountain ashes dip approximately 1[degree] to the east; and gravity measurements of basement geometry demonstrate a dip of 11.0--13.7[degree] eastward. Extrapolating a uniform rate of tilt, the dip of the basement suggest that sedimentation in the OV began in the late Miocene. The character of deformation across the study area is consistent with motion on the Coyote warp anticlinal trend, near the base of the Sierra Nevada. The author propose that the Coyote warp has acted as a tectonic hinge, accommodating westward rotation of the Sierra Nevada and eastward rotation of the northern OV.

  15. Rockfall failure mechanisms in Yosemite Valley, California (USA)

    NASA Astrophysics Data System (ADS)

    Matasci, Battista; Guerin, Antoine; Carrea, Dario; Stock, Greg M.; Jaboyedoff, Michel; Collins, Brian

    2014-05-01

    Rockfall hazard is especially high in Yosemite Valley, with tens of rockfalls inventoried every year. A rockfall on 5 October 2013 from Ahwiyah Point consisted of a volume of 740 cubic meters and occurred within the perimeter of a larger event on 28 March 2009 that released 25'400 cubic meters of rock (Zimmer et al., 2012). In both events (2009 and 2013), the initial rockfall volumes dislodged a second one approximately equivalent in size by impacting the cliff below the source area during the fall. Rock fragments of up to several cubic meters were deposited on the talus slope, damaging a heavily used and recently reconstructed hiking path. We performed extensive mapping of structural features for several cliffs of Yosemite Valley to improve the assessment of the most susceptible rockfall areas. In particular we mapped and characterized the main brittle structures, the exfoliation joints and the failure mechanisms of the past rockfalls. Several failure mechanisms exist in Yosemite including the propagation of brittle structures that may lead to tensile, planar sliding, wedge sliding or toppling failures. Frequently, topographically-parallel exfoliation joints and topographically-oblique discontinuities coexist, resulting in complex failures. We also developed a methodology to examine how the distribution of joints within the cliff faces of Yosemite Valley affects overall stability with respect to the identified failure mechanisms. For these analyses, we used terrestrial laser scanning (TLS) to collect high resolution point clouds of the vertical and overhanging rock faces throughout the Valley. This provided the necessary 3D data to identify the main joint sets, perform spacing and trace length measurements, and calculate volumes of previous and potential rockfalls. We integrated this information with stability calculations to identify the likely failure mechanisms for each area of cliff and to obtain the number of potential failures per square meter of cliff face

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

    NASA Astrophysics Data System (ADS)

    Medellín-Azuara, Josué; MacEwan, Duncan; Howitt, Richard E.; Koruakos, George; Dogrul, Emin C.; Brush, Charles F.; Kadir, Tariq N.; Harter, Thomas; Melton, Forrest; Lund, Jay R.

    2015-09-01

    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 inevitable changes in the state's water management. Currently, agricultural, environmental, and urban uses compete for groundwater, resulting in substantial overdraft in dry years with lowering of water tables, which in turn increases pumping costs and reduces groundwater pumping capacity. In this study, SWAP (an economic model of agricultural production and water use in California) and C2VISim (the California Department of Water Resources groundwater model for California's Central Valley) are connected. This paper examines the economic costs of pumping replacement groundwater during drought and the potential loss of pumping capacity as groundwater levels drop. A scenario of three additional drought years continuing from 2014 show lower water tables in California's Central Valley and loss of pumping capacity. Places without access to groundwater and with uncertain surface-water deliveries during drought are the most economically vulnerable in terms of crop revenues, employment and household income. This is particularly true for Tulare Lake Basin, which relies heavily on water imported from the Sacramento-San Joaquin Delta. Remote-sensing estimates of idle agricultural land between 2012 and 2014 confirm this finding. Results also point to the potential of a portfolio approach for agriculture, in which crop mixing and conservation practices have substantial roles.

  17. Origin of Hot Creek Canyon, Long Valley caldera, California

    SciTech Connect

    Maloney, N.J. . Dept. of Geological Sciences)

    1993-04-01

    Hot Creek has eroded a canyon some thirty meters deep across the Hot Creek rhyolite flows located in the southeastern moat of Long Valley Caldera. Maloney (1987) showed that the canyon formed by headward erosion resulting from spring sapping along hydrothermally altered fractures in the rhyolite, and the capture of Mammoth Creek. This analysis ignored the continuing uplift of the central resurgent dome. Reid (1992) concluded that the downward erosion of the canyon must have kept pace with the uplift. Long Valley Lake occupied the caldera until 100,000 to 50,000 years before present. The elevation of the shoreline, determined by trigonometric leveling, is 2,166 m where the creek enters the canyon and 2,148 m on the downstream side of the rhyolite. The slope of the strand line is about equal to the stream gradient. The hill was lower and the stream gradient less at the time of stream capture. Rotational uplift increased the stream gradient which increased the rate of downward erosion and formed the V-shaped canyon

  18. Historical Channel Changes in Cache Creek, Capay Valley, California

    NASA Astrophysics Data System (ADS)

    Higgins, S. A.; Kamman, G. R.

    2009-12-01

    Historical channel changes were assessed for the 21-mile segment of Cache Creek through Capay Valley in order to evaluate temporal changes in stream channel morphology. The Capay Valley segment of Cache Creek is primarily a low-gradient channel with a gravel/cobble substrate. Hydrologic conditions have been affected by dam operations that store runoff during the wet season and deliver water during the dry season for downstream irrigation uses. Widespread distribution of invasive plant species has altered the condition of the riparian corridor. The assessment evaluated a hypothesis that historical changes in hydrology and vegetation cover have triggered changes in geomorphic conditions. Historic channel alignments were digitized to assess planform channel adjustments. Results illustrate a dynamic system with frequent channel movements throughout the historic period. Evaluation of longitudinal channel adjustments revealed a relatively stable bed surface elevation since the 1930’s. Comparisons of cross-sectional channel geometry for topographic profiles surveyed in 1984 were compared to equivalent features in a LiDAR survey from 2008. The comparisons show a relatively consistent channel geometry that has maintained a similar form despite rather large planform adjustments with areas of bank retreat in excess of 500 feet. Results suggest that the study reach has maintained a relatively stable morphology through a series of dynamic planform adjustments during the historic period.

  19. Uranium-series dating of pedogenic carbonates from the Livermore Valley, California

    SciTech Connect

    Knauss, K.G.

    1981-01-07

    A uranium-series dating technique has been applied to pedogenic carbonates from the Livermore Valley in California. The results from geomorphologically distinct Quaternary alluvial units are internally consistent and for one alluvial unit are corroborated by a concordant /sup 14/C age for an associated wood fragment. In appropriate situations, age dates for pedogenic carbonates derived using this technique may provide a time stratigraphy for alluvial units and hence provide some limits (minimum age) for last fault movement.

  20. Variation of P-Wave Velocity before the Bear Valley, California, Earthquake of 24 February 1972.

    PubMed

    Robinson, R; Wesson, R L; Ellsworth, W L

    1974-06-21

    Residuals for P-wave traveltimes at a seismnograph station near Bear Valley, California, for small, precisely located local earthquakes at distances of 20 to 70 kilometers show a sharp increase of nearly 0.3 second about 2 months before a magnitude 5.0 earthquake that occurred within a few kilometers of the station. This indicates that velocity changes observed elsewhere premonitory to earthquakes, possibly related to dilatancy, occur along the central section of the San Andreas fault system. PMID:17784227

  1. The mechanism of intrusion of the Inyo Dike, Long Valley Caldera, California

    NASA Technical Reports Server (NTRS)

    Reches, Zeev; Fink, Jonathan

    1988-01-01

    The dike geometry of the 11-km-long Inyo Dike at the margins of the Long Valley calderas in eastern California is explained here in terms of the interaction between tectonic stresses and local variations in host rock rheology. Relationships between tectonic and magmatic stresses are evaluated, and the magnitude of magmatic pressure at the depth necessary to get the dike to the surface is estimated. The application of the model to other volcanoes is also discussed.

  2. Relating seismic swarms and deformation in Long Valley Caldera, California

    NASA Astrophysics Data System (ADS)

    Montgomery-Brown, E. K.; Ellsworth, W. L.; Hill, D. P.; Shelly, D. R.; Langbein, J. O.; Lisowski, M.; Llenos, A. L.

    2013-12-01

    Earthquake swarm activity in the South Moat Seismic Zone (SMSZ) in Long Valley caldera began increasing following the onset of slow inflation of the resurgent dome in 2011. From 1980 through 1999 the caldera produced recurring earthquake swarms in the SMSZ accompanied by an 80-cm uplift of the resurgent dome. Since 2000, the caldera has been quieter than from 1980 to 1999, but it experienced a gradual 7-cm uplift episode in 2002-2003 and currently the caldera has been gradually uplifting since 2011 at less than half of the peak uplift velocity observed in the late 1990's. Two of the recent swarms in October/November of 2012 and March 2013 have been accompanied by small deformation transients during which caldera uplift paused for about a week despite otherwise steady inflation. To better understand this recent activity, we cross correlate seismic velocity waveforms from individual events recorded by the Long Valley seismic network to identify similar clusters (families) of earthquakes and analyze their temporal recurrence. Then, we use representative waveforms from each family as templates to search the continuous waveforms from the deep borehole seismometers in the Long Valley Exploratory Well (MDH1) for repeating, yet smaller, earthquakes. MDH1 consists of two three-component instruments, located 2592 m and 2263 m below ground level, that provide 6 channels with very low background noise relative to surface seismometers. The cross correlations identify about 25 times more earthquakes with most magnitudes ranging from -1 to +0.5, determined from an empirical relationship between catalog magnitude and observed amplitude on MDH1. We apply an ETAS model to the augmented catalog to detect subtle changes in background earthquake rates that might suggest a change in stressing rate. For comparison with the change in seismicity rates, a geodetically determined stress change is estimated from a simple model of the continuous GPS data. We model the uplift from 2011 to

  3. Water quality and supply issues of irrigated agricultural regions – lessons from the San Joaquin Valley of California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The San Joaquin Valley of California covers 4 million hectares of farmland and produces $25 billion of agricultural products annually, but its average annual rainfall ranges from only 130 mm in the south to 330 mm in the north and nearly all occur in the winter. On the east side of the valley, irrig...

  4. Optimal pumping strategies for managing shallow, poorquality groundwater, western San Joaquin Valley, California

    USGS Publications Warehouse

    Barlow, P.; Wagner, B.; Belitz, K.

    1995-01-01

    Continued agricultural productivity in the western San Joaquin Valley, California, is threatened by the presence of shallow, poor-quality groundwater that can cause soil salinization. We evaluate the management alternative of using groundwater pumping to control the altitude of the water table and provide irrigation water requirements. A transient, three-dimensional, groundwater flow model was linked with nonlinear optimization to simulate management alternatives for the groundwater flow system. Optimal pumping strategies have been determined that substantially reduce the area subject to a shallow water table and bare-soil evaporation (that is, areas with a water table within 2.1 m of land surface) and the rate of drainflow to on-farm drainage systems. Optimal pumping strategies are constrained by the existing distribution of wells between the semiconfined and confined zones of the aquifer, by the distribution of sediment types (and associated hydraulic conductivities) in the western valley, and by the historical distribution of pumping throughout the western valley.

  5. Winter fog is decreasing in the fruit growing region of the Central Valley of California

    NASA Astrophysics Data System (ADS)

    Baldocchi, Dennis; Waller, Eric

    2014-05-01

    The Central Valley of California is home to a variety of fruit and nut trees. These trees account for 95% of the U.S. production, but they need a sufficient amount of winter chill to achieve rest and quiescence for the next season's buds and flowers. In prior work, we reported that the accumulation of winter chill is declining in the Central Valley. We hypothesize that a reduction in winter fog is cooccurring and is contributing to the reduction in winter chill. We examined a 33 year record of satellite remote sensing to develop a fog climatology for the Central Valley. We find that the number of winter fog events, integrated spatially, decreased 46%, on average, over 32 winters, with much year to year variability. Less fog means warmer air and an increase in the energy balance on buds, which amplifies their warming, reducing their chill accumulation more.

  6. Chemical and isotopic prediction of aquifer temperatures in the geothermal system at Long Valley, California

    USGS Publications Warehouse

    Fournier, R.O.; Sorey, M.L.; Mariner, R.H.; Truesdell, A.H.

    1979-01-01

    Temperatures of aquifers feeding thermal springs and wells in Long Valley, California, estimated using silica and Na-K-Ca geothermometers and warm spring mixing models, range from 160/dg to about 220??C. This information was used to construct a diagram showing enthalpy-chloride relations for the various thermal waters in the Long Valley region. The enthalpy-chloride information suggests that a 282 ?? 10??C aquifer with water containing about 375 mg chloride per kilogram of water is present somewhere deep in the system. That deep water would be related to ??? 220??C Casa Diablo water by mixing with cold water, and to Hot Creek water by first boiling with steam loss and then mixing with cold water. Oxygen and deuterium isotopic data are consistent with that interpretation. An aquifer at 282??C with 375 mg/kg chloride implies a convective heat flow in Long Valley of 6.6 ?? 107 cal/s. ?? 1979.

  7. Global positioning system surveying to monitor land subsidence in Sacramento Valley, California, USA

    USGS Publications Warehouse

    Ikehara, M.E.

    1994-01-01

    A subsidence research program began in 1985 to document the extent and magnitude of land subsidence in Sacramento Valley, California, an area of about 15 600 km2m, using Global Positioning System (GPS) surveying. In addition to periodic conventional spirit levelling, an examination was made of the changes in GPS-derived ellipsoidal height differences (summary differences) between pairs of adjacent bench marks in central Sacramento Valley from 1986 to 1989. The average rates of land subsidence in the southern Sacramento Valley for the past several decades were determined by comparing GPS-derived orthometric heights with historic published elevations. A maximum average rate of 0.053 m year-1 (0.90 m in 17 years) of subsidence has been measured. -Author

  8. Cotton yield losses and ambient ozone concentrations in California's San Joaquin Valley

    SciTech Connect

    Olszyk, D.; Bytnerowicz, A.; Kats, G.; Reagan, C.; Hake, S.

    1993-01-01

    Based on controlled experiments and simulation modeling, ozone air pollution has been estimated to cause significant yield losses to cotton. The study reported here was conducted to verify losses for Acala cotton (Gossypium hirsutum SJ2) along a gradient of ambient ozone (O3) concentrations across the San Joaquin Valley in California. Cotton was grown in nonfiltered (NF) and charcoal-filtered (CF) open-top chambers at four sites during the 1988-1989 summer growing seasons. Cotton yields were reduced in NF compared to CF air in general proportion to O3 concentrations across all sites and years. Greatest cotton yield losses were at Dinuba on the east side of the San Joaquin Valley and lowest were on the west side of the valley. Ozone injury symptoms on cotton were most noticeable in areas with greatest yield losses.

  9. Monitoring land subsidence in Sacramento Valley, California, using GPS

    USGS Publications Warehouse

    Blodgett, J.C.; Ikehara, M.E.; Williams, Gary E.

    1990-01-01

    Land subsidence measurement is usually based on a comparison of bench-mark elevations surveyed at different times. These bench marks, established for mapping or the national vertical control network, are not necessarily suitable for measuring land subsidence. Also, many bench marks have been destroyed or are unstable. Conventional releveling of the study area would be costly and would require several years to complete. Differences of as much as 3.9 ft between recent leveling and published bench-mark elevations have been documented at seven locations in the Sacramento Valley. Estimates of land subsidence less than about 0.3 ft are questionable because elevation data are based on leveling and adjustment procedures that occured over many years. A new vertical control network based on the Global Positioning System (GPS) provides highly accurate vertical control data at relatively low costs, and the survey points can be placed where needed to obtain adequate areal coverage of the area affected by land subsidence.

  10. Mathematical ground-water model of Indian Wells Valley, California

    USGS Publications Warehouse

    Bloyd, R.M., Jr.; Robson, S.G.

    1971-01-01

    A mathematical model of the Indian Wells Valley ground-water basin was developed and verified. The alternating-direction implicit method was used to compute the mathematical solution. It was assumed that there are only two aquifers in the valley, one being deep and the other shallow. Where the shallow aquifer occurs, the underlying deep aquifer is confined or artesian. Flow between the aquifers under steady-state conditions is assumed to be in one direction, from deep to shallow. The transmissivity of the deep aquifer ranges from about 250,000 to 22,000 gallons per day per foot and from about 25,000 to 5,000 gallons per day per foot for the shallow aquifer. The storage coefficient for the deep aquifer ranges from 1 x 10 -4 to 0.20. Steady-state recharge and discharge in each aquifer was estimated to be 9,850 acre-feet per year. Ground-water pumping, sewage-effluent recharge, and capture of ground-water discharge occurred under non-steady-state conditions. Most of the ground-water pumpage is near Ridgecrest and Inyokern and in the area between the two towns. By 1968 pumpage in the deep aquifer had caused a reversal in the ground-water gradient south of China Lake and small water-level declines over most of the aquifer. The model for the deep aquifer was verified under steady-state and non-steady-state conditions. The shallow aquifer was verified under steady-state conditions only. The verified model was then used to generate 1983 water-level conditions in the deep aquifer.

  11. Descriptions and chemical analyses for selected wells in eastern Sacramento Valley, California

    USGS Publications Warehouse

    Fogelman, Ronald P.; Rockwell, Gerald L.

    1977-01-01

    The Sacramento Valley occupies the northern one-third of the Great Central Valley of California. The study area of this report includes about 1,300 square miles in the eastern part of the Sacramento Valley, extending from the latitude of Roseville on the south to the latitude of Chico on the north and bounded on the east by the foothills of the Sierra Nevada and on the west by the Sacramento River, in Yolo, Yuba, Placer, Sutter, and Butte Counties. Between February and July 1976, 809 wells were canvassed, and during August and September 1976, water samples were collected for chemical analysis from 222 of the wells. Field determinations of alkalinity, conductance, pH, and temperature were made on the site at the time of sampling. The samples were then field prepared for shipment and analysis for selected constituents and properties at the Geological Survey Central Laboratory, Arvada, Colo. Descriptive data for water wells, chemical data, and the location of wells are presented. This is the third in a series of data reports showing baseline well data and water-quality data in the Sacramento Valley and is in cooperation with the California Department of Water Resources. (Woodard-USGS)

  12. Heber Demonstration Plant geothermal binary electric power generation, Imperial County, California (13(B) water assessment report). Final report

    SciTech Connect

    Not Available

    1980-09-01

    This water assessment report prepared under the provisions of Section 13(b) is an assessment of water requirements and water supply availability for a proposed Geothermal Demonstration Plant near Heber, California. It discusses (1) principal findings, (2) project description, (3) water supply and availability, and (4) effects of the project.

  13. Imperial Reform in the Neo-Colonies: The University of California's Basic Plan for Higher Education in Colombia.

    ERIC Educational Resources Information Center

    Gonzalez, Gilbert

    1982-01-01

    The "Plan Basico" for Colombian higher education, elaborated in the 1960s at the University of California under the sponsorship of the Agency for International Development, is criticized as nondemocratic and designed to serve the political and economic interests of the United States and the national elite rather than the Colombian people in…

  14. Hydrogeologic characterization of the Modesto Area, San Joaquin Valley, California

    USGS Publications Warehouse

    Burow, Karen R.; Shelton, Jennifer L.; Hevesi, Joseph A.; Weissmann, Gary S.

    2004-01-01

    Hydrogeologic characterization was done to develop an understanding of the hydrogeologic setting near Modesto by maximizing the use of existing data and building on previous work in the region. A substantial amount of new lithologic and hydrologic data are available that allow a more complete and updated characterization of the aquifer system. In this report, geologic units are described, a database of well characteristics and lithology is developed and used to update the regional stratigraphy, a water budget is estimated for water year 2000, a three-dimensional spatial correlation map of aquifer texture is created, and recommendations for future data collection are summarized. The general physiography of the study area is reflected in the soils. The oldest soils, which have low permeability, exist in terrace deposits, in the interfan areas between the Stanislaus, Tuolumne, and Merced Rivers, at the distal end of the fans, and along the San Joaquin River floodplain. The youngest soils have high permeability and generally have been forming on the recently deposited alluvium along the major stream channels. Geologic materials exposed or penetrated by wells in the Modesto area range from pre-Cretaceous rocks to recent alluvium; however, water-bearing materials are mostly Late Tertiary and Quaternary in age. A database containing information from more than 3,500 drillers'logs was constructed to organize information on well characteristics and subsurface lithology in the study area. The database was used in conjunction with a limited number of geophysical logs and county soil maps to define the stratigraphic framework of the study area. Sequences of red paleosols were identified in the database and used as stratigraphic boundaries. Associated with these paleosols are very coarse grained incised valley-fill deposits. Some geophysical well logs and other sparse well information suggest the presence of one of these incised valley-fill deposits along and adjacent to the

  15. Renewed inflation of Long Valley Caldera, California (2011 to 2014)

    NASA Astrophysics Data System (ADS)

    Montgomery-Brown, E. K.; Wicks, C. W.; Cervelli, P. F.; Langbein, J. O.; Svarc, J. L.; Shelly, D. R.; Hill, D. P.; Lisowski, M.

    2015-07-01

    Slow inflation began at Long Valley Caldera in late 2011, coinciding with renewed swarm seismicity. Ongoing deformation is concentrated within the caldera. We analyze this deformation using a combination of GPS and InSAR (TerraSAR-X) data processed with a persistent scatterer technique. The extension rate of the dome-crossing baseline during this episode (CA99 to KRAC) is 1 cm/yr, similar to past inflation episodes (1990-1995 and 2002-2003), and about a tenth of the peak rate observed during the 1997 unrest. The current deformation is well modeled by the inflation of a prolate spheroidal magma reservoir ˜7 km beneath the resurgent dome, with a volume change of ˜6 × 106 m3/yr from 2011.7 through the end of 2014. The current data cannot resolve a second source, which was required to model the 1997 episode. This source appears to be in the same region as previous inflation episodes, suggesting a persistent reservoir.

  16. Renewed inflation of Long Valley Caldera, California (2011 to 2014)

    USGS Publications Warehouse

    Montgomery-Brown, Emily; Wicks, Chuck; Cervelli, Peter F.; Langbein, John O.; Svarc, Jerry L.; Shelly, David R.; Hill, David P.; Lisowski, Michael

    2015-01-01

    Slow inflation began at Long Valley Caldera in late 2011, coinciding with renewed swarm seismicity. Ongoing deformation is concentrated within the caldera. We analyze this deformation using a combination of GPS and InSAR (TerraSAR-X) data processed with a persistent scatterer technique. The extension rate of the dome-crossing baseline during this episode (CA99 to KRAC) is 1 cm/yr, similar to past inflation episodes (1990–1995 and 2002–2003), and about a tenth of the peak rate observed during the 1997 unrest. The current deformation is well modeled by the inflation of a prolate spheroidal magma reservoir ∼7 km beneath the resurgent dome, with a volume change of ∼6 × 106 m3/yr from 2011.7 through the end of 2014. The current data cannot resolve a second source, which was required to model the 1997 episode. This source appears to be in the same region as previous inflation episodes, suggesting a persistent reservoir.

  17. Gravity and fault structures, Long Valley caldera, California

    SciTech Connect

    Carle, S.F.; Goldstein, N.E.

    1987-07-01

    The main and catastrophic phase of eruption in Long Valley occurred 0.73 m.y. ago with the eruption of over 600 km/sup 3/ of rhyolitic magma. Subsequent collapse of the roof rocks produced a caldera which is now elliptical in shape, 32 km east-west by 17 km north-south. The caldera, like other large Quarternary silicic ash-flow volcanoes that have been studied by various workers, has a nearly coincident Bouguer gravity low. Earlier interpretations of the gravity anomaly have attributed the entire anomaly to lower density rocks filling the collapsed structure. However, on the basis of many additional gravity stations and supporting subsurface data from several new holes, a much more complex and accurate picture has emerged of caldera structure. From a three-dimensional inversion of the residual Bouguer gravity data we can resolve discontinuities that seem to correlate with extensions of pre-caldera faults into the caldera and faults associated with the ring fracture. Some of these faults are believed related to the present-day hydrothermal upflow zone and the zone of youngest volcanic activity within the caldera.

  18. Scenario liquefaction hazard maps of Santa Clara Valley, Northern California

    USGS Publications Warehouse

    Holzer, T.L.; Noce, T.E.; Bennett, M.J.

    2009-01-01

    Maps showing the probability of surface manifestations of liquefaction in the northern Santa Clara Valley were prepared with liquefaction probability curves. These curves were based on complementary cumulative frequency distributions of the liquefaction potential index (LPI) for surficial geologic units in the study area. LPI values were computed with extensive cone penetration test soundings. Maps were developed for three earthquake scenarios, an M 7.8 event on the San Andreas fault comparable to the 1906 event, an M 6.7 event on the Hayward fault comparable to the 1868 event, and an M 6.9 event on the Calaveras fault. Ground motions were estimated with the Boore and Atkinson (2008) attenuation relation. Liquefaction is predicted for all three events in young Holocene levee deposits along the major creeks. Liquefaction probabilities are highest for the M 7.8 earthquake, ranging from 0.33 to 0.37 if a 1.5 m deep water table is assumed, and from 0.10 to 0.14, if a 5 m deep water table is assumed. Liquefaction probabilities of the other surficial geologic units are less than 0.05. Probabilities for the scenario earthquakes are generally consistent with observations during historical earthquakes.

  19. Radon-222 in groundwater of the Long Valley caldera, California

    NASA Astrophysics Data System (ADS)

    Wollenberg, H. A.; Smith, A. R.; Mosier, D. F.; Flexser, S.; Clark, M.

    1984-03-01

    In the Long Valley caldera, where seismicity has continued essentially uninterrupted since mid-1980 and uplift is documented, samples of water from hot, warm, and cold springs have been collected since September, 1982, and their222Rn concentrations analyzed. Concurrently, rocks encompassing the hydrologic systems feeding the springs were analyzed for their radioelement contents, because their uranium is the ultimate source of the222Rn in the water. The222Rn concentration in the springs varies inversely with their temperature and specific conductance. High concentrations (1500 to 2500 picocuries per liter) occur in dilute cold springs on the margins of the caldera, while low contents (12 to 25 pCi/l) occur in hot to boiling springs. Springwater radon concentrations also correlate slightly with the uranium content of the encompassing rocks. A continuous monitoring system was installed in August, 1983, at a spring issuing from basalt, to provide hourly records of radon concentration. A gamma detector is submerged in a natural pool, and we have observed that the radioactivity measured in this manner is due almost entirely to the222Rn concentration of the water. Initial operation shows diurnal and semidiurnal variations in the222Rn concentration of the springwater that are ascribed to earth tides, suggesting that those variations are responding to small changes in stress in the rocks encompassing the hydrologic system.

  20. Radon in groundwater of the Long Valley Caldera, California

    SciTech Connect

    Flexser, S.; Wollenberg, H.A.; Smith, A.R.

    1987-04-01

    In the Long Valley caldera, an area of recently (approx.550 y) active volcanism and current seismic activity, /sup 222/Rn concentrations in hot, warm, and cold spring waters have been measured since 1982. Rn contents of the waters correlate inversely with temperature and specific conductance, with high concentrations (1500 to 2500 pCi/l) occurring in dilute cold springs on the margins of the caldera, and low concentrations (12 to 25 pCi/l) in hot to boiling springs. Rn correlates only slightly with the uranium contents of the wide range of rocks which host the hydrological system feeding the springs. These environmental effects on the radon record may mask responses to small or distant seismic, volcanic, or crustal deformation events. To date, anomalous changes in water-borne Rn have been observed in connection with at least one earthquake, which occurred close to the monitoring site. This continuing study points out that an understanding of the geological setting, its associated hydrological system, and environmental influences is necessary to properly evaluate concentrations and changes in groundwater radioactivity.

  1. Habitat suitability and conservation of the Giant Gartersnake (Thamnophis gigas) in the Sacramento Valley of California

    USGS Publications Warehouse

    Halstead, B.J.; Wylie, G.D.; Casazza, M.L.

    2010-01-01

    Resource managers often have little information regarding the habitat requirements and distribution of rare species. Factor analysis-based habitat suitability models describe the ecological niche of a species and identify locations where these conditions occur on the landscape using existing occurrence data. We used factor analyses to assess the suitability of habitats for Thamnophis gigas (Giant Gartersnake), a rare, threatened species endemic to the Central Valley of California, USA, and to map the locations of habitat suitable for T. gigas in the Sacramento Valley. Factor analyses indicated that the niche of T. gigas is composed of sites near rice agriculture with low stream densities. Sites with high canal densities and near wetlands also appeared suitable, but results for these variables were sensitive to potential sampling bias. In the Sacramento Valley, suitable habitats occur primarily in the central portion of the valley floor. Based upon the results of the factor analyses, recovery planning for T. gigas will require an on-the-ground assessment of the current distribution and abundance of T. gigas, maintaining the few remaining natural wetlands and the practice of rice agriculture in the Sacramento Valley, and studying the effects of agricultural practices and land use changes on populations of T. gigas. ?? 2010 by the American Society of Ichthyologists and Herpetologists.

  2. Habitat suitability and conservation of the giant gartersnake (Thamnophis gigas) in the Sacramento Valley of California

    USGS Publications Warehouse

    Halstead, Brian J.; Wylie, Glenn D.; Casazza, Michael L.

    2010-01-01

    Resource managers often have little information regarding the habitat requirements and distribution of rare species. Factor analysis-based habitat suitability models describe the ecological niche of a species and identify locations where these conditions occur on the landscape using existing occurrence data.We used factor analyses to assess the suitability of habitats for Thamnophis gigas (Giant Gartersnake), a rare, threatened species endemic to the Central Valley of California, USA, and to map the locations of habitat suitable for T. gigas in the Sacramento Valley. Factor analyses indicated that the niche of T. gigas is composed of sites near rice agriculture with low stream densities. Sites with high canal densities and near wetlands also appeared suitable, but results for these variables were sensitive to potential sampling bias. In the Sacramento Valley, suitable habitats occur primarily in the central portion of the valley floor. Based upon the results of the factor analyses, recovery planning for T. gigas will require an on-the-ground assessment of the current distribution and abundance of T. gigas, maintaining the few remaining natural wetlands and the practice of rice agriculture in the Sacramento Valley, and studying the effects of agricultural practices and land use changes on populations of T. gigas.

  3. Nutrient Flux from Mediterranean Coastal Streams: Carpinteria Valley, California

    NASA Astrophysics Data System (ADS)

    Robinson, T. H.; Leydecker, A.; Melack, J. M.; Keller, A. A.

    2003-12-01

    Along the southern California coast, near Santa Barbara, California, we are measuring nutrient export from specific land uses and developing a model to predict nutrient export at a watershed scale. The area is characterized by a Mediterranean-like climate and short steep catchments producing flashy runoff. The six land uses include chaparral, avocado orchards, greenhouse agriculture, open-field nurseries, and residential and commercial development. Sampling sites are located on defined drainages or storm drains that collect runoff from relatively homogeneous areas representing each land use. Stream water samples are taken once a week during the rainy season, every two weeks during the dry season and every one to four hours during storms. Samples are analyzed for ammonium, nitrate, phosphate, total dissolved nitrogen and particulate nitrogen and phosphorus. Intensive sampling at the thirteen sites of the study was conducted throughout Water Year (WY) 2002 and 2003. We determine discharge from measurements of stage derived from pressure transducers at all sampling sites. This information is then converted to flux at a high temporal resolution. Wet and dry season sampling has shown that nitrate baseflow concentrations vary over three orders of magnitude, from a few micromoles per liter in undeveloped catchments, to a few 100 æmol/L in agricultural and urban watersheds, to 1000 æmol/L where intensive "greenhouse" agriculture dominates. Nitrate loading ranged from a few moles per hectare per storm at undeveloped and residential sites to hundreds at the greenhouse site. Phosphate concentrations show a similar, but smaller, variation from 1 to 100 æmol/L, although the loading is comparable at 1-100 moles/ha-storm. Stormflow concentrations fluctuate with the storm hydrograph: phosphate increases with flow, while nitrate typically decreases due to dilution from runoff probably from impervious surfaces. Nitrate export patterns indicate a marked difference between land use

  4. Using Imaging Spectrometry to Identify Crops in California's Central Valley

    NASA Astrophysics Data System (ADS)

    Shivers, S.; Roberts, D. A.

    2015-12-01

    With a growing global population, limited resources and a changing climate, understanding and monitoring the distribution of our food and water resources is essential to their sustainability. Regional food yield estimates and water resource accounting are dependent upon accurate agricultural records. Crop mapping provides farmers, managers, and policymakers the information necessary to anticipate annual food supplies and water demands by better understanding the distribution of species. While on the ground crop accounting usually happens yearly at the county level and requires significant time and labor inputs, remote sensing has the potential to map crops and monitor their health over a greater spatial area with more frequent time intervals. Specifically, imaging spectrometers have the capability to produce imagery at high spectral and spatial resolutions, which may allow for differentiation of crops at the field-level scale. In this research 14 crop species and soil were classified in Kern County, California using canonical discriminant analysis (CDA) and Multiple Endmember Spectral Mixture Analysis (MESMA) on airborne visible/infrared imaging spectrometer (AVIRIS) imagery from June 2013. Imagery was then degraded to Landsat spectral resolution and reclassified for comparison. Results with the AVIRIS imagery show an overall accuracy of 69.0% using MESMA and 89.4% using CDA with nine out of fourteen crop species showing user and producer errors under ten percent. Lower accuracy was found for OLI data. This research illustrates great potential for field-level crop mapping with imaging spectrometry.

  5. Precipitation depth-duration and frequency characteristics for Antelope Valley, Mojave Desert, California

    USGS Publications Warehouse

    Blodgett, J.C.

    1995-01-01

    Methods to evaluate changes in the volume of storm runoff from drainage basins that are likely to be urbanized are needed by land-use planning agencies to establish criteria for the design of flood-control systems. To document the changes in runoff volume of basins that may be urbanized, nine small basins that are considered representative of varying hydrologic conditions in Antelope Valley, California, were selected for detailed study. Precipitation and stream-gaging stations were established and data were collected for the period 1990-93. The data collected at these U.S. Geological Survey stations were supplemented by data collected at 35 Long-term precipitation stations operated by the National Oceanic and Atmospheric Administration and the Los Angeles County Department of Public Works. These data will be used to calibrate and verify rainfall-runoff models for the nine basins. Results of the model runs will then be used as a guide for estimating basin runoff characteristics throughout Antelope Valley. Annual precipitation in Antelope Valley ranges from more than 20 inches in the mountains to less than 4 inches on the valley floor. Most precipitation in the valley falls during the months of December through March, but cyclonic storms in the fall and convectional storms in the summer sometimes occur. The duration of most storms ranges from 1 to 8 days, but most of the precipitation usually occurs within the first 2 days. Many parts of the valley have been affected by storms with precipitation depths that equal or exceed 0.60 inch per hour. The storms of January 1943 and March 1983 were the most intense storms of record, with recurrence intervals greater than 100 years in some parts of the valley. Depth-duration ratios were calculated by disaggregating daily total precipitation data for intervals of 1, 2, 3, 4, 6, 12, and 18 hours for storms that occurred during 1990-93. The hourly total precipitation data were then disaggregated at 5-minute intervals. A comparison

  6. SRTM Perspective View with Landsat Overlay: Santa Paula, and Santa Clara River Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Rectangular fields of the agriculturally rich Santa Clara River Valley are visible in this perspective view generated using data from the Shuttle Radar Topography Mission and an enhanced Landsat image. The Santa Clara River, which lends its name to this valley, flows from headwaters near Acton, California, 160 km (100 miles) to the Pacific Ocean, and is one of only two natural river systems remaining in southern California. In the foreground of this image, the largely dry riverbed can be seen as a bright feature as it winds its way along the base of South Mountain. The bright region at the right end of this portion of the valley is the city of Santa Paula, California. Founded in 1902, this small, picturesque town at the geographic center of Ventura County is referred to as the 'Citrus Capital of the World.' The city is surrounded by orange, lemon, and avocado groves and is a major distribution point for citrus fruits in the United States. The bright, linear feature in the center of the valley is State Highway 126, the valley's 'main drag.' For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors, from Landsat data, approximate natural color.

    The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory

  7. Hydrology of the Valley-fill and carbonate-rock reservoirs, Pahrump Valley, Nevada-California

    USGS Publications Warehouse

    Malmberg, Glenn T.

    1967-01-01

    This is the second appraisal of the water supply of Pahrump Valley, made 15 years after the first cooperative study. In the first report the average recharge was estimated to be 23,000 acre-feet per year, only 1,000 acre-feet more than the estimate made in this report. All this recharge was considered to be available for development. Because of the difficulty in salvaging the subsurface outflow from the deep carbonate-rock reservoir, this report concludes that the perennial yield may be only 25,000 acre-feet. In 1875, Bennetts and Manse Springs reportedly discharged a total of nearly 10,000 acre-feet of water from the valley-fill reservoir. After the construction of several flowing wells in 1910, the spring discharge began to decline. In the mid-1940's many irrigation wells were drilled, and large-capacity pumps were installed. During the 4-year period of this study (1959-62), the net pumping draft averaged about 25,000 acre-feet per year, or about twice the estimated yield. In 1962 Bennetts Spring was dry, and the discharge from Marse Spring was only 1,400 acre-feet. During the period February 1959-February 1962, pumping caused an estimated storage depletion of 45,000 acre-feet, or 15,000 acre-feet per year. If the overdraft is maintained, depletion of stored water will continue and pumping costs will increase. Water levels in the vicinity of the Pahrump, Manse, and Fowler Ranches declined more than ]0 feet in response to the pumping during this period, and they can be expected to continue to decline at ,the projected rate of more than 3 feet per year. The chemical quality of the pumped water has been satisfactory for irrigation and domestic use. Recycling of water pumped or irrigation, however, could result in deterioration of the water quality with time.

  8. Technical Analysis of In-Valley Drainage Management Strategies for the Western San Joaquin Valley, California

    USGS Publications Warehouse

    Presser, Theresa S.; Schwarzbach, Steven E.

    2008-01-01

    The western San Joaquin Valley is one of the most productive farming areas in the United States, but salt-buildup in soils and shallow groundwater aquifers threatens this area?s productivity. Elevated selenium concentrations in soils and groundwater complicate drainage management and salt disposal. In this document, we evaluate constraints on drainage management and implications of various approaches to management considered in: *the San Luis Drainage Feature Re-Evaluation (SLDFRE) Environmental Impact Statement (EIS) (about 5,000 pages of documentation, including supporting technical reports and appendices); *recent conceptual plans put forward by the San Luis Unit (SLU) contractors (i.e., the SLU Plans) (about 6 pages of documentation); *approaches recommended by the San Joaquin Valley Drainage Program (SJVDP) (1990a); and *other U.S. Geological Survey (USGS) models and analysis relevant to the western San Joaquin Valley. The alternatives developed in the SLDFRE EIS and other recently proposed drainage plans (refer to appendix A for details) differ from the strategies proposed by the San Joaquin Valley Drainage Program (1990a). The Bureau of Reclamation (USBR) in March 2007 signed a record of decision for an in-valley disposal option that would retire 194,000 acres of land, build 1,900 acres of evaporation ponds, and develop a treatment system to remove salt and selenium from drainwater. The recently proposed SLU Plans emphasize pumping drainage to the surface, storing approximately 33% in agricultural water re-use areas, treating selenium through biotechnology, enhancing the evaporation of water to concentrate salt, and identifying ultimate storage facilities for the remaining approximately 67% of waste selenium and salt. The treatment sequence of reuse, reverse osmosis, selenium bio-treatment, and enhanced solar evaporation is unprecedented and untested at the scale needed to meet plan requirements. All drainage management strategies that have been proposed

  9. Airborne observations of methane emissions from rice cultivation in the Sacramento Valley of California

    NASA Astrophysics Data System (ADS)

    Peischl, J.; Ryerson, T. B.; Holloway, J. S.; Trainer, M.; Andrews, A. E.; Atlas, E. L.; Blake, D. R.; Daube, B. C.; Dlugokencky, E. J.; Fischer, M. L.; Goldstein, A. H.; Guha, A.; Karl, T.; Kofler, J.; Kosciuch, E.; Misztal, P. K.; Perring, A. E.; Pollack, I. B.; Santoni, G. W.; Schwarz, J. P.; Spackman, J. R.; Wofsy, S. C.; Parrish, D. D.

    2012-12-01

    Airborne measurements of methane (CH4) and carbon dioxide (CO2) were taken over the rice growing region of California's Sacramento Valley in the late spring of 2010 and 2011. From these and ancillary measurements, we show that CH4 mixing ratios were higher in the planetary boundary layer above the Sacramento Valley during the rice growing season than they were before it, which we attribute to emissions from rice paddies. We derive daytime emission fluxes of CH4 between 0.6 and 2.0% of the CO2 taken up by photosynthesis on a per carbon, or mole to mole, basis. We also use a mixing model to determine an average CH4/CO2 flux ratio of -0.6% for one day early in the growing season of 2010. We conclude the CH4/CO2 flux ratio estimates from a single rice field in a previous study are representative of rice fields in the Sacramento Valley. If generally true, the California Air Resources Board (CARB) greenhouse gas inventory emission rate of 2.7 × 1010 g CH4/yr is approximately three times lower than the range of probable CH4 emissions (7.8-9.3 × 1010 g CH4/yr) from rice cultivation derived in this study. We attribute this difference to decreased burning of the residual rice crop since 1991, which leads to an increase in CH4 emissions from rice paddies in succeeding years, but which is not accounted for in the CARB inventory.

  10. New observations of VOC emissions and concentrations in, above, and around the Central Valley of California

    NASA Astrophysics Data System (ADS)

    Goldstein, A. H.; Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Ormeno, E.; Holzinger, R.; Misztal, P. K.; Karl, T. R.; Guenther, A. B.; Fischer, M. L.; Harley, R. A.; Karlik, J. F.

    2011-12-01

    Large portions of the Central Valley of California are out of compliance with current state and federal air quality standards for ozone and particulate matter, and the relative importance of biogenic and anthropogenic VOC emissions to their photochemical production in this region remains uncertain. In 2009-2011 multiple measurement campaigns were completed investigating the VOC emission inventory and concentration distributions. In 2009 BVOC emissions from more than 20 species of major agricultural crops in California were measured in a greenhouse using branch enclosures by both PTRMS and in-situ GC. Overall, crops were found to emit low amounts of BVOC compared to the natural forests surrounding the valley. Crops mainly emitted methanol and terpenes, with a broad array of other species emitted at lower levels, and all the measured crops showed negligible emissions of isoprene. Navel oranges were the largest crop BVOC emitters measured so a full year of flux measurements were made in an orange grove near Visalia in 2010 by eddy covariance(EC)-PTRMS with two multi-week periods of concentration measurements by hourly in-situ GC, and one month of high mass resolution flux measurements by EC-PTR-TOF-MS. The dominant BVOC emissions from the orange grove were methanol and terpenes, followed by acetone, acetaldehyde, and a low level of emissions for many other species. In 2011 aircraft eddy covariance measurements of BVOC fluxes were made by EC-PTRMS covering a large area of California as part of the California Airborne Bvoc Emission Research in Natural Ecosystem Transects (CABERNET) campaign aimed at improving BVOC emission models on regional scales, mainly profiling BVOC emissions from oak woodlands surrounding the Central Valley. In 2010, hourly in-situ VOC measurements were made via in-situ GC in Bakersfield, CA as part of the CalNex experiment. Additionally, in-situ measurements of fresh motor vehicle exhaust were made in Oakland's Caldecott tunnel. Measurements by

  11. Subsidence in the Central Valley, California 2007 - present measured by InSAR

    NASA Astrophysics Data System (ADS)

    Farr, T. G.; Liu, Z.; Jones, C. E.

    2015-12-01

    Subsidence caused by groundwater pumping in the rich agricultural area of California's Central Valley has been a problem for decades. Over the last few years, interferometric synthetic aperture radar (InSAR) observations from satellite and aircraft platforms have been used to produce maps of subsidence with ~cm accuracy. For this study, we have obtained and analyzed Japanese PALSAR data for 2006 - 2011, Canadian Radarsat-1 data for 2011 - 2013, Radarsat-2 data for 2012 - 2015, and ESA's Sentinel-1A for 2015 and produced maps of subsidence for those periods. High resolution InSAR data were also acquired along the California Aqueduct by the NASA UAVSAR from 2013 - 2015. Using multiple scenes acquired by these systems, we were able to produce the time histories of subsidence at selected locations and transects showing how subsidence varies both spatially and temporally. The maps show that subsidence is continuing in areas with a history of subsidence and that the rates and areas affected have increased due to increased groundwater extraction during the extended western US drought. The high resolution maps from UAVSAR were used to identify and quantify new, highly localized areas of accelerated subsidence along the California Aqueduct that occurred in 2014. The California Department of Water Resources (DWR) funded this work to provide the background and an update on subsidence in the Central Valley to support future policy. Geographic Information System (GIS) files are being furnished to DWR for further analysis of the 4 dimensional subsidence time-series maps. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA.

  12. SRTM Perspective View with Landsat Overlay: San Fernando Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The San Fernando Valley (lower right of center) is part of Los Angeles and includes well over one million people. Two major disasters have occurred here in the last few decades: the 1971 Sylmar earthquake and the 1994 Northridge earthquake. Both quakes caused major damage to homes, freeways, and other structures and included major injuries and fatalities. The Northridge earthquake was the one of the costliest natural disasters in United States history. Understanding earthquake risks requires understanding a location's geophysical setting, and topographic data are of substantial benefit in that regard. Landforms are often characteristic of specific tectonic processes, such as ground movement along faults. Elevation models, such as those produced by the Shuttle Radar Topography Mission (SRTM), are particularly useful in visualizing regional scale landforms that are too large to be seen directly on-site. They can also be used to model the propagation of damaging seismic waves, which helps in urban planning. In recent years, elevation models have also been a critical input to radar interferometric studies, which reveal detailed patterns of ground deformation from earthquakes that had never before been seen.

    This perspective view was generated by draping a Landsat satellite image over a preliminary topographic map from SRTM. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive.

    The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect

  13. Recent land-use/land-cover change in the Central California Valley

    USGS Publications Warehouse

    Soulard, Christopher E.; Wilson, Tamara S.

    2013-01-01

    Open access to Landsat satellite data has enabled annual analyses of modern land-use and land-cover change (LULCC) for the Central California Valley ecoregion between 2005 and 2010. Our annual LULCC estimates capture landscape-level responses to water policy changes, climate, and economic instability. From 2005 to 2010, agriculture in the region fluctuated along with regulatory-driven changes in water allocation as well as persistent drought conditions. Grasslands and shrublands declined, while developed lands increased in former agricultural and grassland/shrublands. Development rates stagnated in 2007, coinciding with the onset of the historic foreclosure crisis in California and the global economic downturn. We utilized annual LULCC estimates to generate interval-based LULCC estimates (2000–2005 and 2005–2010) and extend existing 27 year interval-based land change monitoring through 2010. Resulting change data provides insights into the drivers of landscape change in the Central California Valley ecoregion and represents the first, continuous, 37 year mapping effort of its kind.

  14. Optical variability of seawater in relation to particle concentration, composition, and size distribution in the nearshore marine environment at Imperial Beach, California

    NASA Astrophysics Data System (ADS)

    Woźniak, SłAwomir B.; Stramski, Dariusz; Stramska, Malgorzata; Reynolds, Rick A.; Wright, Vanessa M.; Miksic, Ezra Y.; Cichocka, Marta; Cieplak, Agnieszka M.

    2010-08-01

    We examined optical variability of seawater in relation to particle concentration, composition, and size distribution in the nearshore marine environment at Imperial Beach, California, over a period of 1.5 years. Measurements included the hyperspectral inherent optical properties (IOPs) of seawater (particulate beam attenuation, particulate and CDOM absorption coefficients within the spectral range 300-850 nm), particle size distribution (PSD) within the diameter range 2-60 μm, and the mass concentrations of suspended particulate matter (SPM), particulate organic carbon (POC), and chlorophyll a (Chl). The particulate assemblage spanned a wide range of concentrations and composition, from the dominance of mineral particles (POC/SPM < 0.06) with relatively steep PSDs to the high significance or dominance of organic particles (POC/SPM > 0.25) with considerably greater contribution of larger-sized particles. Large variability in the particulate characteristics produced correspondingly large variability in the IOPs; up to 100-fold variation in particulate absorption and scattering coefficients and several-fold variation in the SPM-specific and POC-specific coefficients. Analysis of these data demonstrates that knowledge of general characteristics about the particulate composition and size distribution leads to improved interpretations of the observed optical variability. We illustrate a multistep empirical approach for estimating proxies of particle concentration (SPM and POC), composition (POC/SPM), and size distribution (median diameter) from the measured IOPs in a complex coastal environment. The initial step provides information about a proxy for particle composition; other particulate characteristics are subsequently derived from relationships specific to different categories of particulate composition.

  15. Evapotranspiration estimates using remote-sensing data, Parker and Palo Verde valleys, Arizona and California

    USGS Publications Warehouse

    Raymond, L.H.; Rezin, K.V.

    1986-01-01

    In 1981 the U.S. Geological Survey established an experimental project to assess the possible and practical use of remote sensing data to estimate evapotranspiration as an approximation of consumptive use in the lower Colorado River flood plain. The project area was in Parker Valley, Arizona. The approach selected was to measure the areas covered by each type of vegetation using remote sensing data in various types of analyses and to multiply each area by a predetermined water use rate. Two calibration and six remote sensing methods of classifying crop types were compared for cost, accuracy, consistency, and labor requirements. Included were one method each for field reconnaissance using 1982 data, low altitude (< than 5,000 ft) aerial photography using 1982 data, and visual photointerpretation of Landsat satellite images using 1981 and 1982 data; two methods for medium-altitude (15,000-18,000 ft) aerial photography using 1982 data; and three methods for digital Landsat satellite images using 1981 data. A test of the most promising digital processing method, which used three image dates, was made in part of Palo Verde Valley, California, where 1981 crop data were more complete than in Parker Valley. Of the eight methods studied, the three-date digital processing method was the most consistent and least labor-intensive; visual photointerpretation of Landsat images was the least expensive. Evapotranspiration estimates from crop classifications by all methods differed by a maximum of 6%. Total evapotranspiration calculated from crop data and phreatophyte maps in 1981 ranged from 12% lower in Palo Verde Valley to 17% lower in Parker Valley than consumptive use calculated by water budgets. The difference was greater in Parker Valley because the winter crop data were not included. (Author 's abstract)

  16. Water availability and land subsidence in the Central Valley, California, USA

    NASA Astrophysics Data System (ADS)

    Faunt, Claudia C.; Sneed, Michelle; Traum, Jon; Brandt, Justin T.

    2015-11-01

    The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the valley, the San Joaquin Valley, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007-2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin Valley. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central Valley Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.

  17. Water availability and land subsidence in the Central Valley, California, USA

    NASA Astrophysics Data System (ADS)

    Faunt, Claudia C.; Sneed, Michelle; Traum, Jon; Brandt, Justin T.

    2016-05-01

    The Central Valley in California (USA) covers about 52,000 km2 and is one of the most productive agricultural regions in the world. This agriculture relies heavily on surface-water diversions and groundwater pumpage to meet irrigation water demand. Because the valley is semi-arid and surface-water availability varies substantially, agriculture relies heavily on local groundwater. In the southern two thirds of the valley, the San Joaquin Valley, historic and recent groundwater pumpage has caused significant and extensive drawdowns, aquifer-system compaction and subsidence. During recent drought periods (2007-2009 and 2012-present), groundwater pumping has increased owing to a combination of decreased surface-water availability and land-use changes. Declining groundwater levels, approaching or surpassing historical low levels, have caused accelerated and renewed compaction and subsidence that likely is mostly permanent. The subsidence has caused operational, maintenance, and construction-design problems for water-delivery and flood-control canals in the San Joaquin Valley. Planning for the effects of continued subsidence in the area is important for water agencies. As land use, managed aquifer recharge, and surface-water availability continue to vary, long-term groundwater-level and subsidence monitoring and modelling are critical to understanding the dynamics of historical and continued groundwater use resulting in additional water-level and groundwater storage declines, and associated subsidence. Modeling tools such as the Central Valley Hydrologic Model, can be used in the evaluation of management strategies to mitigate adverse impacts due to subsidence while also optimizing water availability. This knowledge will be critical for successful implementation of recent legislation aimed toward sustainable groundwater use.

  18. Evapotranspiration estimates using remote-sensing data, Parker and Palo Verde valleys, Arizona and California

    USGS Publications Warehouse

    Raymond, Lee H.; Rezin, Kelly V.

    1989-01-01

    In 1981 the U.S. Geological Survey established an experimental project to assess the possible and practical use of remote-sensing data to estimate evapotranspiration as an approximation of consumptive use of water in the lower Colorado River flood plain. The project area was in Parker Valley, Arizona. The approach selected was to measure the areas covered by each type of vegetation, using remote-sensing data in various types of analyses, and to multiply each area by a predetermined water-use rate. Two calibration and six remote-sensing methods of classifying crop types were compared for cost, accuracy, consistency, and labor requirements. Included were one method each for field reconnaissance using 1982 data, low-altitude (less than 5,000 feet) aerial photography using 1982 data, and visual photointerpretation of Landsat satellite images using 1981 and 1982 data; two methods for medium-altitude (15,000-18,000 feet) aerial photography using 1982 data; and three methods for digital Landsat satellite images using 1981 data. A test of the most promising digital-processing method, which used three image dates, was made in part of Palo Verde Valley, California, where 1981 crop data were more complete than in Parker Valley. Of the eight methods studied, the two-date digital-processing method was the most consistent and least labor intensive for identifying two or three major crops; visual photointerpretation of Landsat images was the least expensive. Evapotranspiration estimates from crop classifications by all methods differed by a maximum of 6 percent. Total evapotranspiration calculated from crop data and phreatophyte maps in 1981 ranged from 11 percent lower in Palo Verde Valley to 17 percent lower in Parker Valley than consumptive use calculated by water budgets. The difference was greater in Parker Valley because the winter crop data were not included.

  19. Subsurface and petroleum geology of the southwestern Santa Clara Valley ("Silicon Valley"), California

    USGS Publications Warehouse

    Stanley, Richard G.; Jachens, Robert C.; Lillis, Paul G.; McLaughlin, Robert J.; Kvenvolden, Keith A.; Hostettler, Frances D.; McDougall, Kristin A.; Magoon, Leslie B.

    2002-01-01

    Gravity anomalies, historical records of exploratory oil wells and oil seeps, new organic-geochemical results, and new stratigraphic and structural data indicate the presence of a concealed, oil-bearing sedimentary basin beneath a highly urbanized part of the Santa Clara Valley, Calif. A conspicuous isostatic-gravity low that extends about 35 km from Palo Alto southeastward to near Los Gatos reflects an asymmetric, northwest-trending sedimentary basin comprising low-density strata, principally of Miocene age, that rest on higher-density rocks of Mesozoic and Paleogene(?) age. Both gravity and well data show that the low-density rocks thin gradually to the northeast over a distance of about 10 km. The thickest (approx 4 km thick) accumulation of low-density material occurs along the basin's steep southwestern margin, which may be controlled by buried, northeast-dipping normal faults that were active during the Miocene. Movement along these hypothetical normal faults may been contemporaneous (approx 17–14 Ma) with sedimentation and local dacitic and basaltic volcanism, possibly in response to crustal extension related to passage of the northwestward-migrating Mendocino triple junction. During the Pliocene and Quaternary, the normal faults and Miocene strata were overridden by Mesozoic rocks, including the Franciscan Complex, along northeastward-vergent reverse and thrust faults of the Berrocal, Shannon, and Monte Vista Fault zones. Movement along these fault zones was accompanied by folding and tilting of strata as young as Quaternary and by uplift of the modern Santa Cruz Mountains; the fault zones remain seismically active. We attribute the Pliocene and Quaternary reverse and thrust faulting, folding, and uplift to compression caused by local San Andreas Fault tectonics and regional transpression along the Pacific-North American Plate boundary. Near the southwestern margin of the Santa Clara Valley, as many as 20 exploratory oil wells were drilled between 1891

  20. Peak horizontal acceleration and velocity from strong-motion records including records from the 1979 imperial valley, California, earthquake

    USGS Publications Warehouse

    Joyner, William B.; Boore, David M.

    1981-01-01

    We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceleration and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the data from the magnitude dependence.

  1. Integrated model of the shallow and deep hydrothermal systems in the East Mesa area, Imperial Valley, California

    SciTech Connect

    Riney, T.D.; Pritchett, J.W.; Rice, L.F.

    1982-01-01

    Geological, geophysical, thermal, petrophysical and hydrological data available for the East Mesa hydrothermal system that are pertinent to the construction of a computer model of the natural flow of heat and fluid mass within the system are assembled and correlated. A conceptual model of the full system is developed and a subregion selected for quantitative modeling. By invoking the Boussinesq approximation, valid for describing the natural flow of heat and mass in a liquid hydrothermal system, it is found practical to carry computer simulations far enough in time to ensure that steady-state conditions are obtained. Initial calculations for an axisymmetric model approximating the system demonstrate that the vertical formation permeability of the deep East Mesa system must be very low (k/sub v/ approx. 0.25 to 0.5 md). Since subsurface temperature and surface heat flow data exhibit major deviations from the axisymmetric approximation, exploratory three-dimensional calculations are performed to assess the effects of various mechanisms which might operate to produce such observed asymmetries. A three-dimensional model evolves from this iterative data synthesis and computer analysis which includes a hot fluid convective source distributed along a leaky fault radiating northward from the center of the hot spot and realistic variations in the reservoir formation properties.

  2. Integrated model of the shallow and deep hydrothermal systems in the East Mesa area, Imperial Valley, California

    USGS Publications Warehouse

    Riney, T. David; Pritchett, J.W.; Rice, L.F.

    1982-01-01

    Geological, geophysical, thermal, petrophysical and hydrological data available for the East Mesa hydrothermal system that are pertinent to the construction of a computer model of the natural flow of heat and fluid mass within the system are assembled and correlated. A conceptual model of the full system is developed and a subregion selected for quantitative modeling. By invoking the .Boussinesq approximation, valid for describing the natural flow of heat and mass in a liquid hydrothermal system, it is found practical to carry computer simulations far enough in time to ensure that steady-state conditions are obtained. Initial calculations for an axisymmetric model approximating the system demonstrate that the vertical formation permeability of the deep East Mesa system must be very low (kv ~ 0.25 to 0.5 md). Since subsurface temperature and surface heat flow data exhibit major deviations from the axisymmetric approximation, exploratory three-dimensional calculations are performed to assess the effects of various mechanisms which might operate to produce such observed asymmetries. A three-dimensional model evolves from this iterative data synthesis and computer analysis which includes a hot fluid convective source distributed along a leaky fault radiating northward from the center of the hot spot and realistic variations in the reservoir formation properties.

  3. Fog composition in the Central Valley of California over three decades

    NASA Astrophysics Data System (ADS)

    Herckes, P.; Marcotte, A. R.; Wang, Y.; Collett, J. L.

    2015-01-01

    Numerous fog studies have been conducted in the Central Valley of California since the 1980s, making it one of the most studied locations in the world in terms of fog chemistry. The present work reviews observational fog studies in the area and discusses overall chemical composition as well as spatial variability and temporal variability. Regionally there is a clear gradient in fog occurrence with less fog and lower density (liquid water content, LWC) fog in the southern part of the Valley (Bakersfield) compared to more northern locations like Fresno or Davis. Chemically, fogs in the southern valley have higher solute loadings and lower pH compared to more northern locations (Davis and Fresno). Overall fog chemistry is dominated in the valley by the ammonia-nitric acid-ammonium nitrate system with sulfate being a rather minor component, especially at more northern locations and in more recent years. Fog pH in recent years is consistently higher than 5, showing an absence of acid in fogs in this region. LWC values appear to have decreased over recent years (less dense fogs). An airport visibility assessment of fog frequency reveals that overall dense fogs (visibility of less than 1/4 mile) have decreased by ~ 50% over the last 30 years.

  4. Descriptions and chemical analyses for selected wells in the Central Sacramento Valley, California

    USGS Publications Warehouse

    Fogelman, Ronald P.

    1976-01-01

    The Sacramento Valley occupies the northern one-third of the Great Central Valley of California. The study area of this report includes about 1,200 square miles (3,100 square kilometers) adjacent to the Sacramento River from Knights Landing to Los Molinos, in parts of Yolo, Sutter, Colusa, Glenn, Butte, and Tehama Counties. Between April and August 1975, 559 wells were canvassed, and during September and October 1975, water samples were collected for chemical analysis from 209 of these wells. Field determinations of alkalinity, conductance, pH , and temperature were made on the site at the time of sampling. Samples were prepared in the field for shipment and analysis for individual constituents at the Geological Survey Central Laboratory, Salt Lake City, Utah. Descriptive data for water wells are listed, chemical data are tabulated, and the location of wells is shown on maps. (Woodard-USGS)

  5. Ground-Water Modeling of the Death Valley Region, Nevada and California

    USGS Publications Warehouse

    Belcher, W.R.; Faunt, C.C.; Sweetkind, D.S.; Blainey, J.B.; San Juan, C. A.; Laczniak, R.J.; Hill, M.C.

    2006-01-01

    The Death Valley regional ground-water flow system (DVRFS) of southern Nevada and eastern California covers an area of about 100,000 square kilometers and contains very complex geology and hydrology. Using a computer model to represent the complex system, the U.S. Geological Survey simulated ground-water flow in the Death Valley region for use with U.S. Department of Energy projects in southern Nevada. The model was created to help address contaminant cleanup activities associated with the underground nuclear testing conducted from 1951 to 1992 at the Nevada Test Site and to support the licensing process for the proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada.

  6. Quaternary tectonics and basin history of Pahrump and Stewart Valleys, Nevada and California. [Yucca Mountain Project

    SciTech Connect

    Hoffard, J.L. )

    1991-05-01

    The Pahrump fault system is an active fault system located in Pahrump and Stewart Valleys, Nevada and California, in the southern part of the Basin and Range Province. This system is 50 km long by 30 km wide and is comprised of three fault zones: the right-lateral East Nopah fault zone, the right-oblique Pahrump Valley fault zone, and the normal West Spring Mountains fault zone. All three zones have geomorphic evidence for late Quaternary activity. Analysis of active fault patterns and seismic reflection lines suggests that the Pahrump basin has had a two-stage genesis, an early history associated with a period of low angle detachment faulting probably active 10-15 Ma, and a more recent history related to the present dextral shear system, probably active post-4 Ma.

  7. Quaternary tectonics and basin history of Pahrump and Stewart Valleys, Nevada and California

    SciTech Connect

    Hoffard, J.L.

    1991-05-01

    The Pahrump fault system is an active fault system located in Pahrump and Stewart Valleys, Nevada and California, in the southern part of the Basin and Range Province. This system is 50 km long by 30 km wide and is comprised of three fault zones: the right-lateral East Nopah fault zone, the right-oblique Pahrump Valley fault zone, and the normal West Spring Mountains fault zone. All three zones have geomorphic evidence for late Quaternary activity. Analysis of active fault patterns and seismic reflection lines suggests that the Pahrump basin has had a two-stage genesis, an early history associated with a period of low angle detachment faulting probably active 10-15 Ma, and a more recent history related to the present dextral shear system, probably active post-4 Ma.

  8. Construction of 3-D geologic framework and textural models for Cuyama Valley groundwater basin, California

    USGS Publications Warehouse

    Sweetkind, Donald S.; Faunt, Claudia C.; Hanson, Randall T.

    2013-01-01

    Groundwater is the sole source of water supply in Cuyama Valley, a rural agricultural area in Santa Barbara County, California, in the southeasternmost part of the Coast Ranges of California. Continued groundwater withdrawals and associated water-resource management concerns have prompted an evaluation of the hydrogeology and water availability for the Cuyama Valley groundwater basin by the U.S. Geological Survey, in cooperation with the Water Agency Division of the Santa Barbara County Department of Public Works. As a part of the overall groundwater evaluation, this report documents the construction of a digital three-dimensional geologic framework model of the groundwater basin suitable for use within a numerical hydrologic-flow model. The report also includes an analysis of the spatial variability of lithology and grain size, which forms the geologic basis for estimating aquifer hydraulic properties. The geologic framework was constructed as a digital representation of the interpreted geometry and thickness of the principal stratigraphic units within the Cuyama Valley groundwater basin, which include younger alluvium, older alluvium, and the Morales Formation, and underlying consolidated bedrock. The framework model was constructed by creating gridded surfaces representing the altitude of the top of each stratigraphic unit from various input data, including lithologic and electric logs from oil and gas wells and water wells, cross sections, and geologic maps. Sediment grain-size data were analyzed in both two and three dimensions to help define textural variations in the Cuyama Valley groundwater basin and identify areas with similar geologic materials that potentially have fairly uniform hydraulic properties. Sediment grain size was used to construct three-dimensional textural models that employed simple interpolation between drill holes and two-dimensional textural models for each stratigraphic unit that incorporated spatial structure of the textural data.

  9. ACCURACY OF PROJECT-WIDE WATER USES FROM A WATER BALANCE: A CASE STUDY FROM SOUTHERN CALIFORNIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A detailed water balance was conducted on the Imperial Valley in southern California for the years 1987 to 1996. The area included all lands within the boundaries defined, including farms, towns, road, etc. This analysis included surface and subsurface inflows, rainfall, surface and subsurface outfl...

  10. Emissions of organic carbon and methane from petroleum and dairy operations in California's San Joaquin Valley

    NASA Astrophysics Data System (ADS)

    Gentner, D. R.; Ford, T. B.; Guha, A.; Boulanger, K.; Brioude, J.; Angevine, W. M.; de Gouw, J. A.; Warneke, C.; Gilman, J. B.; Ryerson, T. B.; Peischl, J.; Meinardi, S.; Blake, D. R.; Atlas, E.; Lonneman, W. A.; Kleindienst, T. E.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; VandenBoer, T. C.; Markovic, M. Z.; Murphy, J. G.; Harley, R. A.; Goldstein, A. H.

    2014-05-01

    Petroleum and dairy operations are prominent sources of gas-phase organic compounds in California's San Joaquin Valley. It is essential to understand the emissions and air quality impacts of these relatively understudied sources, especially for oil/gas operations in light of increasing US production. Ground site measurements in Bakersfield and regional aircraft measurements of reactive gas-phase organic compounds and methane were part of the CalNex (California Research at the Nexus of Air Quality and Climate Change) project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions, and provide average source profiles. To examine the spatial distribution of emissions in the San Joaquin Valley, we developed a statistical modeling method using ground-based data and the FLEXPART-WRF transport and meteorological model. We present evidence for large sources of paraffinic hydrocarbons from petroleum operations and oxygenated compounds from dairy (and other cattle) operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes, most of which have limited previous in situ measurements or characterization in petroleum operation emissions. Observed dairy emissions were dominated by ethanol, methanol, acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin Valley; observations of methane were well correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin Valley highlight the dominance of dairy operations for methane emissions. The petroleum operations source profile was developed using the composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil. The observed source profile is

  11. Characterization of alluvial sources in the Owens Valley of eastern California using Fourier shape analysis

    SciTech Connect

    Wagoner, J.L.; Younker, J.L.

    1982-03-01

    Two-dimensional quartz grain shape was used to characterize sand grains from different source areas in the Owens Valley of eastern California. Combining a mathematical description of the grain outline and multivariate discriminant analysis, we have shown that quartz from clastic source rocks has a distinctive imprint when compared to samples from granitic, volcanic, or mixed fluvial source areas. Alternatively, quartz provided by a granitic source could equally well have been interpreted as if it were derived from any of the other sources considered. This study provides a standard of comparison for further analysis of sediment deposited in arid alluvial environments.

  12. Mapping alluvial fans in Death Valley, California, using multichannel thermal infrared images

    NASA Technical Reports Server (NTRS)

    Gillespie, A. R.; Kahle, A. B.; Pallluconi, F. D.

    1984-01-01

    Alluvial fans have been mapped in Death Valley, California using NASA's 8-12 micron six-channel airborne Thermal Infrared Multispectral Scanner (TIMS). Both composition and relative age differences were recognized. Age unit boundries are generally consistent with those obtained by conventional mapping. Composition was verified by field investigation and comparison with existing geologic maps. Bedrock and its young derived fan gravels have similar emissivities. The original composition of the fans is modified by differential erosion and weathering, permitting relative age mapping with TIMS.

  13. Spasmodic tremor and possible magma injection in long valley caldera, eastern california.

    PubMed

    Ryall, A; Ryall, F

    1983-03-25

    Intensive microearthquake swarms with the appearance of volcanic tremor have been observed in the southwest part of Long Valley caldera, southeastern California. This activity, possibly associated with magma injection, began 6 weeks after several strong (magnitude 6+) earthquakes in an area south of the caldera and has continued sporadically to the present time. The earthquake sequence and magmatic activity are part of a broad increase in tectonic activity in a 15,000-square-kilometer region surrounding the "White Mountains seismic gap," an area with high potential for the next major earthquake in the western Great Basin. PMID:17735195

  14. Models for volcanic processes in Long Valley, California: testing by continental drilling

    SciTech Connect

    Rundle, J.B.

    1984-01-01

    This paper gives a brief review of recent tectonic activity in the Long Valley, California, caldera, occurring since 1978. A series of major earthquakes, combined with ground uplift, crustal strain, gravity changes, hydrothermal system changes, and earthquake swarm activity all suggest the recent existence of a significant high level magmatic intrusion as the root cause of the activity. These data are outlined here, along with a program to investigate the nature and current evolution of this active caldera system. Current activities and future plans are also discussed. 23 references, 5 figures.

  15. Evaluation of the hydrologic system and selected water-management alternatives in the Owens Valley, California

    USGS Publications Warehouse

    Danskin, Wesley R.

    1998-01-01

    The Owens Valley, a long, narrow valley along the east side of the Sierra Nevada in eastcentral California, is the main source of water for the city of Los Angeles. The city diverts most of the surface water in the valley into the Owens River?Los Angeles Aqueduct system, which transports the water more than 200 miles south to areas of distribution and use. Additionally, ground water is pumped or flows from wells to supplement the surface-water diversions to the river? aqueduct system. Pumpage from wells needed to supplement water export has increased since 1970, when a second aqueduct was put into service, and local residents have expressed concerns that the increased pumping may have a detrimental effect on the environment and the native vegetation (indigenous alkaline scrub and meadow plant communities) in the valley. Native vegetation on the valley floor depends on soil moisture derived from precipitation and from the unconfined part of a multilayered ground-water system. This report, which describes the evaluation of the hydrologic system and selected water-management alternatives, is one in a series designed to identify the effects that ground-water pumping has on native vegetation and evaluate alternative strategies to mitigate any adverse effects caused by pumping. The hydrologic system of the Owens Valley can be conceptualized as having three parts: (1) an unsaturated zone affected by precipitation and evapotranspiration; (2) a surface-water system composed of the Owens River, the Los Angeles Aqueduct, tributary streams, canals, ditches, and ponds; and (3) a saturated ground-water system contained in the valley fill. Analysis of the hydrologic system was aided by development of a ground-water flow model of the ?aquifer system,? which is defined as the most active part of the ground-water system and which includes nearly all of the Owens Valley except for the area surrounding the Owens Lake. The model was calibrated and verified for water years 1963?88 and

  16. Early Tertiary magmatism and probable Mesozoic fabrics in the Black Mountains, Death Valley, California

    NASA Astrophysics Data System (ADS)

    Miller, Martin G.; Friedman, Richard M.

    1999-01-01

    We report two early Tertiary U-Pb zircon ages for pegmatite from the Black Mountains of Death Valley, California. These ages, 54.7 ± 0.6 Ma and 56 ± 3 Ma, are unique for much of southeastern California. The samples belong to a pegmatite suite that occupies part of the footwall of the Badwater turtleback, a late Tertiary extensional feature; similar but undated pegmatite intrudes the footwalls of the Copper Canyon and Mormon Point turtlebacks farther south. The pegmatite suite demonstrates that fabric development on the turtlebacks was at least a two-stage process. Fabrics cut by these pegmatites likely formed during the Mesozoic, whereas those that involve them formed during late Tertiary extension.

  17. California GAMA Program: Groundwater Ambient Monitoring and Assessment Results for the Sacramento Valley and Volcanic Provinces of Northern California

    SciTech Connect

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2005-01-20

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as methyl tert butyl ether (MTBE) from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater monitoring plan, and led to the initiation of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The primary objective of the California Aquifer Susceptibility (CAS) project (under the GAMA Program) is to assess water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement this groundwater assessment program. In 2003, LLNL carried out this vulnerability study in the Sacramento Valley and Volcanic Provinces. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3 method). In addition, stable oxygen isotope measurements

  18. Identification of carotenoids in ancient salt from Death Valley, Saline Valley, and Searles Lake, California, using laser Raman spectroscopy.

    PubMed

    Winters, Y D; Lowenstein, T K; Timofeeff, M N

    2013-11-01

    Carotenoids are common components of many photosynthetic organisms and are well known from the red waters of hypersaline ecosystems where they are produced by halophilic algae and prokaryotes. They are also of great interest as biomarkers in extraterrestrial samples. Few laser Raman spectroscopy studies have examined ancient field samples, where pigments and microscopic life are less defined. Here, we have identified carotenoids in ancient halite brine inclusions, 9 ka to 1.44 Ma in age, from borehole cores taken from Death Valley, Saline Valley, and Searles Lake, California, for the first time with laser Raman spectroscopy. Carotenoids occurred in fluid inclusions as colorless to red-brown amorphous and crystalline masses associated with spheroidal algal cells similar in appearance to the common halophilic alga Dunaliella. Spectra from carotenoid standards, including β-carotene, lycopene, and lutein, were compared to microscopically targeted carotenoids in fluid inclusions. Carotenoids produced characteristic bands in the Raman spectrum, 1000-1020 cm⁻¹ (v₃), 1150-1170 cm⁻¹ (v₂), and 1500-1550 cm⁻¹ (v₁), when exposed to visible laser excitation. Laser Raman analyses confirmed the presence of carotenoids with these characteristic peaks in ancient halite. A number of band sets were repeated at various depths (ages), which suggests the stability of this class of organic molecules. Carotenoids appear well preserved in ancient salt, which supports other observations, for example, preserved DNA and live cells, that fluid inclusions in buried halite deposits preserve intact halophilic microbial ecosystems. This work demonstrates the value of laser Raman spectroscopy and carotenoids in extraterrestrial exploration for remnants of microbial life. PMID:24283928

  19. Our Choice/Nuestra Opción: The Imperial County, California, Childhood Obesity Research Demonstration Study (CA-CORD)

    PubMed Central

    Ibarra, Leticia; Binggeli-Vallarta, Amy; Moody, Jamie; McKenzie, Thomas L.; Angulo, Janette; Hoyt, Helina; Chuang, Emmeline; Ganiats, Theodore G.; Gahagan, Sheila; Ji, Ming; Zive, Michelle; Schmied, Emily; Arredondo, Elva M.; Elder, John P.

    2015-01-01

    Abstract Background: Despite recent declines among young children, obesity remains a public health burden in the United States, including among Latino/Hispanic children. The determining factors are many and are too complex to fully address with interventions that focus on single factors, such as parenting behaviors or school policies. In this article, we describe a multisector, multilevel intervention to prevent and control childhood obesity in predominantly Mexican-origin communities in Southern California, one of three sites of the CDC-funded Childhood Obesity Research Demonstration (CA-CORD) study. Methods: CA-CORD is a partnership between a university-affiliated research institute, a federally qualified health center, and a county public health department. We used formative research, advisory committee members' recommendations, and previous research to inform the development of the CA-CORD project. Our theory-informed multisector, multilevel intervention targets improvements in four health behaviors: fruit, vegetable, and water consumption; physical activity; and quality sleep. Intervention partners include 1200 families, a federally qualified health center (including three clinics), 26 early care and education centers, two elementary school districts (and 20 elementary schools), three community recreation centers, and three restaurants. Intervention components in these sectors target changes in behaviors, policies, systems, and the social and physical environment. Evaluation activities include assessment of the primary outcome, BMI z-score, at baseline, 12-, and 18-months post-baseline, and sector evaluations at baseline, 12, and 24 months. Conclusions: Identifying feasible and effective strategies to prevent and control childhood obesity has the potential to effect real changes in children's current and future health status. PMID:25584664

  20. Structural and lithologic study of northern California Coast Range and Sacramento Valley, California

    NASA Technical Reports Server (NTRS)

    Rich, E. I. (Principal Investigator); Steele, W. C.

    1973-01-01

    The author has identified the following significant results. Photgeologic examination of repetitive multispectral ERTS-1 imagery of Northern California has disclosed several systems of linear features which may be important for the interpretation of the structural history of California. They are separated from an orthogonal system of linears in the Klamath Mts. by a set of discontinuous southeast-trending linear features (the Mendocino system) which is traceable from the Pacific Coast, at Cape Mendocino, into the eastern foothills of the Sierra Nevada. Within the Sierra Nevada, the Mendocino system separates the north-trending Sierran system from a set of linears characteristic of the Modoc Plateau. With minor exception, little overlap exists among the systems which suggests a decipherable chronology and evolutionary history for the region. The San Andres system of linears appears to truncate or co-exist with most of the other systems in the northern Coast Ranges. The Mendocino system truncates the Klamath, Sierran, and Modoc systems. The Sierran system may represent fundamental and long-persisting pre-late Paleozoic zones of crustal weakness which have been reactivated from time to time. The Mendocino system was possibly developed in early Mesozoic and is important to the structural framework of Northern California.

  1. Atmospheric transport of organophosphate pesticides from California's Central Valley to the Sierra Nevada Mountains

    USGS Publications Warehouse

    Zabik, John M.; Seiber, James N.

    1993-01-01

    Atmospheric transport of organophosphate pesticides from California's Central Valley to the Sierra Nevada mountains was assessed by collecting air- and wet-deposition samples during December, January, February, and March, 1990 to 1991. Large-scale spraying of these pesticides occurs during December and January to control insect infestations in valley orchards. Sampling sites were placed at 114- (base of the foothills), 533-, and 1920-m elevations. Samples acquired at these sites contained chlorpyrifos [phosphorothioic acid; 0,0-diethyl 0-(3,5,6-trichloro-2-pyridinyl) ester], parathion [phosphorothioic acid, 0-0-diethylo-(4-nitrophenyl) ester], diazinon {phosphorothioic acid, 0,0-diethyl 0-[6-methyl-2-(1-methylethyl)-4-pyrimidinyl] ester} diazinonoxon {phosphoric acid, 0,0-diethyl 0-[6-methyl-2-(1-methylethyl)-4-pyrimidinyl] ester}, and paraoxon [phosphoric acid, 0,0-diethyl 0-(4-nitrophenyl) ester] in both air and wet deposition samples. Air concentrations of chloropyrifos, diazinon and parathion ranged from 13 to 13 000 pg/m3 at the base of the foothills. At 533-m air concentrations were below the limit of quantification (1.4 pg/m3) to 83 pg/m3 and at 1920 m concentrations were below the limit of quantification. Concentrations in wet deposition varied with distance and elevation from the Central Valley. Rainwater concentrations at the base of the foot hills ranged from 16 to 7600 pg/mL. At 533-m rain and snow water concentrations ranged from below the limit of quantification (1.3 pg/mL) to 140 pg/mL and at 1920 m concentrations ranged from below the limit of quantification to 48 pg/mL. These findings indicate that atmospheric transport of pesticides applied in the valley to the Sierra Nevada mountains is occurring, but the levels decrease as distance and elevation increase from the valley floor.

  2. Structure of the San Fernando Valley region, California: implications for seismic hazard and tectonic history

    USGS Publications Warehouse

    Langenheim, V.E.; Wright, T.L.; Okaya, D.A.; Yeats, R.S.; Fuis, G.S.; Thygesen, K.; Thybo, H.

    2011-01-01

    Industry seismic reflection data, oil test well data, interpretation of gravity and magnetic data, and seismic refraction deep-crustal profiles provide new perspectives on the subsurface geology of San Fernando Valley, home of two of the most recent damaging earthquakes in southern California. Seismic reflection data provide depths to Miocene–Quaternary horizons; beneath the base of the Late Miocene Modelo Formation are largely nonreflective rocks of the Middle Miocene Topanga and older formations. Gravity and seismic reflection data reveal the North Leadwell fault zone, a set of down-to-the-north faults that does not offset the top of the Modelo Formation; the zone strikes northwest across the valley, and may be part of the Oak Ridge fault system to the west. In the southeast part of the valley, the fault zone bounds a concealed basement high that influenced deposition of the Late Miocene Tarzana fan and may have localized damage from the 1994 Northridge earthquake. Gravity and seismic refraction data indicate that the basin underlying San Fernando Valley is asymmetric, the north part of the basin (Sylmar subbasin) reaching depths of 5–8 km. Magnetic data suggest a major boundary at or near the Verdugo fault, which likely started as a Miocene transtensional fault, and show a change in the dip sense of the fault along strike. The northwest projection of the Verdugo fault separates the Sylmar subbasin from the main San Fernando Valley and coincides with the abrupt change in structural style from the Santa Susana fault to the Sierra Madre fault. The Simi Hills bound the basin on the west and, as defined by gravity data, the boundary is linear and strikes ~N45°E. That northeast-trending gravity gradient follows both the part of the 1971 San Fernando aftershock distribution called the Chatsworth trend and the aftershock trends of the 1994 Northridge earthquake. These data suggest that the 1971 San Fernando and 1994 Northridge earthquakes reactivated portions of

  3. Faulting at Mormon Point, Death Valley, California: A low-angle normal fault cut by high-angle faults

    NASA Astrophysics Data System (ADS)

    Keener, Charles; Serpa, Laura; Pavlis, Terry L.

    1993-04-01

    New geophysical and fault kinematic studies indicate that late Cenozoic basin development in the Mormon Point area of Death Valley, California, was accommodated by fault rotations. Three of six fault segments recognized at Mormon Point are now inactive and have been rotated to low dips during extension. The remaining three segments are now active and moderately to steeply dipping. From the geophysical data, one active segment appears to offset the low-angle faults in the subsurface of Death Valley.

  4. Geochemical studies in the Indian Pass and Picacho Peak Bureau of Land Management Wilderness study areas, imperial county, Southern California

    USGS Publications Warehouse

    Smith, D.B.; Berger, B.R.; Tosdal, R.M.

    1987-01-01

    The U.S. Geological Survey has conducted geochemical studies in the Indian Pass (CDCA-355), 124 km2, and Picacho Peak (CDCA-355A), 23 km2, Wilderness Study Areas (WSA's) as part of a program to evaluate the mineral resource potential of designated areas in the California Desert Conservation Area. These two WSA's are of particular interest because they lie within a region which has intermittently produced significant quantities of Au since the mid-1800's, and is currently the site of much exploration activity for additional Au resources. Within a 15-km radius of the WSA's, there is one actively producing gold mine, a major deposit which began production in 1986, and one recently announced discovery. In the reconnaissance geochemical surveys of the two WSA's - 177 ??m (-80 mesh) stream sediments, heavy-mineral concentrates from stream sediments, and rocks were prepared and analyzed. Four areas of possible exploration interest were identified within the WSA's. The first area is characterized by anomalous W and Bi in nonmagnetic heavy-mineral concentrates, and is underlain primarily by the Mesozoic Orocopia Schist which has been intruded by monzogranite of Oligocene age. Alteration and mineralization appear to be localized near the intrusive contact. The mineralized rock at the surface contains secondary Cu and Fe minerals where the monzogranite intrudes the metabasite horizons of the Orocopia Schist and scheelite where the monzogranite intrudes marble within the Orocopia Schist. The second area is characterized by anomalous As, Sb, Ba, B, and Sr in nonmagnetic heavy-mineral concentrates and by anomalous As in - 177 ??m stream sediments. Geologically, this area is underlain by metasedimentary and metavolcanic rocks of Jurassic(?) age; a biotite monzogranite of Jurassic(?) age; and Tertiary volcanic and hypabyssal rocks composed of flows, domes, and tuffs of intermediate to silicic composition. All these rock types are cut by a set of north-south-striking normal faults

  5. An emission inventory of agricultural internal combustion engines for California`s San Joaquin Valley

    SciTech Connect

    Coe, D.; Chinkin, L.; Reiss, R.

    1996-12-31

    Previous work concluded that stationary agricultural internal combustion (IC) engines are a substantial source of criteria pollutants the San Joaquin Valley (SJV). However, due to time and resource restrictions, earlier work did not include a rigorous survey of engine users. Instead, emission estimates were based on interviews with a few knowledgeable experts (e.g., Department of Agricultural Engineering at U.C. Davis, the Agriculture Extension office of U.C. Davis, Farm Bureau, and Water District offices) or were extrapolated from data designed for other purposes. The purpose of the current study, which was sponsored by the San Joaquin Valley Unified Air Pollution Control District, was to improve the estimate of emissions from this source category by conducting a more comprehensive inventory of this source type based on data collected via a telephone survey of engine users. These survey data were then used to estimate and seasonally allocate emissions for this source category. The findings of this current work show that these emissions are much lower than previously estimated.

  6. Commission Review of a Proposal by California State University Bakersfield to Establish the CSUB Antelope Valley Educational Center. Commission Report 03-07

    ERIC Educational Resources Information Center

    California Postsecondary Education Commission, 2003

    2003-01-01

    This report reviews a proposal by the California State University Board of Trustees and California State University, Bakersfield, to establish a permanent Stated-approved education center in Antelope Valley. The proposed center would be named the CSU Bakersfield Antelope Valley Education Center, and it would serve the growing populations of…

  7. Introduction. [usefulness of modern remote sensing techniques for studying components of California water resources

    NASA Technical Reports Server (NTRS)

    Colwell, R. N.

    1973-01-01

    Since May 1970, personnel on several campuses of the University of California have been conducting investigations which seek to determine the usefulness of modern remote sensing techniques for studying various components of California's earth resources complex. Emphasis has been given to California's water resources as exemplified by the Feather River project and other aspects of the California Water Plan. This study is designed to consider in detail the supply, demand, and impact relationships. The specific geographic areas studied are the Feather River drainage in northern California, the Chino-Riverside Basin and Imperial Valley areas in southern California, and selected portions of the west side of San Joaquin Valley in central California. An analysis is also given on how an effective benefit-cost study of remote sensing in relation to California's water resources might best be made.

  8. A Comparison of Groundwater Storage Using GRACE Data, Groundwater Levels, and a Hydrological Model in Californias Central Valley

    NASA Technical Reports Server (NTRS)

    Kuss, Amber; Brandt, William; Randall, Joshua; Floyd, Bridget; Bourai, Abdelwahab; Newcomer, Michelle; Skiles, Joseph; Schmidt, Cindy

    2011-01-01

    The Gravity Recovery and Climate Experiment (GRACE) measures changes in total water storage (TWS) remotely, and may provide additional insight to the use of well-based data in California's agriculturally productive Central Valley region. Under current California law, well owners are not required to report groundwater extraction rates, making estimation of total groundwater extraction difficult. As a result, other groundwater change detection techniques may prove useful. From October 2002 to September 2009, GRACE was used to map changes in TWS for the three hydrological regions (the Sacramento River Basin, the San Joaquin River Basin, and the Tulare Lake Basin) encompassing the Central Valley aquifer. Net groundwater storage changes were calculated from the changes in TWS for each of the three hydrological regions and by incorporating estimates for additional components of the hydrological budget including precipitation, evapotranspiration, soil moisture, snow pack, and surface water storage. The calculated changes in groundwater storage were then compared to simulated values from the California Department of Water Resource's Central Valley Groundwater- Surface Water Simulation Model (C2VSIM) and their Water Data Library (WDL) Geographic Information System (GIS) change in storage tool. The results from the three methods were compared. Downscaling GRACE data into the 21 smaller Central Valley sub-regions included in C2VSIM was also evaluated. This work has the potential to improve California's groundwater resource management and use of existing hydrological models for the Central Valley.

  9. Results from shallow research drilling at Inyo Domes, Long Valley Caldera, California and Salton Sea geothermal field, Salton Trough, California

    SciTech Connect

    Younker, L.W.; Eichelberger, J.C.; Kasameyer, P.W.; Newmark, R.L.; Vogel, T.A.

    1987-09-01

    This report reviews the results from two shallow drilling programs recently completed as part of the United States Department of Energy Continental Scientific Drilling Program. The purpose is to provide a broad overview of the objectives and results of the projects, and to analyze these results in the context of the promise and potential of research drilling in crustal thermal regimes. The Inyo Domes drilling project has involved drilling 4 shallow research holes into the 600-year-old Inyo Domes chain, the youngest rhyolitic event in the coterminous United States and the youngest volcanic event in Long Valley Caldera, California. The purpose of the drilling at Inyo was to understand the thermal, chemical and mechanical behavior of silicic magma as it intrudes the upper crust. This behavior, which involves the response of magma to decompression and cooling, is closely related to both eruptive phenomena and the establishment of hydrothermal circulation. The Salton Sea shallow research drilling project involved drilling 19 shallow research holes into the Salton Sea geothermal field, California. The purpose of this drilling was to bound the thermal anomaly, constrain hydrothermal flow pathways, and assess the thermal budget of the field. Constraints on the thermal budget links the local hydrothermal system to the general processes of crustal rifting in the Salton Trough.

  10. Water resources development in Santa Clara Valley, California: insights into the human-hydrologic relationship

    SciTech Connect

    Reynolds, Jesse L.; Narasimhan, T.N.

    2000-06-01

    Groundwater irrigation is critical to food production and, in turn, to humankind's relationship with its environment. The development of groundwater in Santa Clara Valley, California during the early twentieth century is instructive because (1) responses to unsustainable resource use were largely successful; (2) the proposals for the physical management of the water, although not entirely novel, incorporated new approaches which reveal an evolving relationship between humans and the hydrologic cycle; and (3) the valley serves as a natural laboratory where natural (groundwater basin, surface watershed) and human (county, water district) boundaries generally coincide. Here, I investigate how water resources development and management in Santa Clara Valley was influenced by, and reflective of, a broad understanding of water as a natural resource, including scientific and technological innovations, new management approaches, and changing perceptions of the hydrologic cycle. Market demands and technological advances engendered reliance on groundwater. This, coupled with a series of dry years and laissez faire government policies, led to overdraft. Faith in centralized management and objective engineering offered a solution to concerns over resource depletion, and a group dominated by orchardists soon organized, fought for a water conservation district, and funded an investigation to halt the decline of well levels. Engineer Fred Tibbetts authored an elaborate water salvage and recharge plan that optimized the local water resources by integrating multiple components of the hydrologic cycle. Informed by government investigations, groundwater development in Southern California, and local water law cases, it recognized the limited surface storage possibilities, the spatial and temporal variability, the relatively closed local hydrology, the interconnection of surface and subsurface waters, and the value of the groundwater basin for its storage, transportation, and treatment

  11. Emissions of organic carbon and methane from petroleum and dairy operations in California's San Joaquin Valley

    NASA Astrophysics Data System (ADS)

    Gentner, D. R.; Ford, T. B.; Guha, A.; Boulanger, K.; Brioude, J.; Angevine, W. M.; de Gouw, J. A.; Warneke, C.; Gilman, J. B.; Ryerson, T. B.; Peischl, J.; Meinardi, S.; Blake, D. R.; Atlas, E.; Lonneman, W. A.; Kleindienst, T. E.; Beaver, M. R.; St. Clair, J. M.; Wennberg, P. O.; VandenBoer, T. C.; Markovic, M. Z.; Murphy, J. G.; Harley, R. A.; Goldstein, A. H.

    2013-10-01

    Petroleum and dairy operations are prominent sources of gas-phase organic compounds in California's San Joaquin Valley. Ground site measurements in Bakersfield and aircraft measurements of reactive gas-phase organic compounds were made in this region as part of the CalNex (California Research at the Nexus of Air Quality and Climate Change) project to determine the sources contributing to regional gas-phase organic carbon emissions. Using a combination of near-source and downwind data, we assess the composition and magnitude of emissions from these prominent sources that are relatively understudied compared to motor vehicles We also developed a statistical modeling method with the FLEXPART-WRF transport and meteorological model using ground-based data to assess the spatial distribution of emissions in the San Joaquin Valley. We present evidence for large sources of paraffinic hydrocarbons from petroleum extraction/processing operations and oxygenated compounds from dairy (and other cattle) operations. In addition to the small straight-chain alkanes typically associated with petroleum operations, we observed a wide range of branched and cyclic alkanes that have limited previous in situ measurements or characterization in emissions from petroleum operations. Observed dairy emissions were dominated by ethanol, methanol, and acetic acid, and methane. Dairy operations were responsible for the vast majority of methane emissions in the San Joaquin Valley; observations of methane were well-correlated with non-vehicular ethanol, and multiple assessments of the spatial distribution of emissions in the San Joaquin Valley highlight the dominance of dairy operations for methane emissions. The good agreement of the observed petroleum operations source profile with the measured composition of non-methane hydrocarbons in unrefined natural gas associated with crude oil suggests a fugitive emissions pathway during petroleum extraction, storage, or processing with negligible

  12. A Hydrogeologic Map of the Death Valley Region, Nevada and California, Developed Using GIS Techniques

    USGS Publications Warehouse

    Faunt, Claudia C.; D'Agnese, Frank A.; Turner, A. Keith

    1997-01-01

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km 2 along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

  13. Integration of AIRSAR and AVIRIS data for Trail Canyon alluvial fan, Death Valley, California

    NASA Technical Reports Server (NTRS)

    Kierein-Young, Kathryn S.

    1995-01-01

    Combining quantitative geophysical information extracted from the optical and microwave wavelengths provides complementary information about both the surface mineralogy and morphology. This study combines inversion results from two remote sensing instruments, a polarimetric synthetic aperture radar, AIRSAR, and an imaging spectrometer, AVIRIS, for Trail Canyon alluvial fan in Death Valley, California. The NASA/JPL Airborne Synthetic Aperture Radar (AIRSAR) is a quad-polarization, three frequency instrument. AIRSAR collects data at C-band = 5.66 cm, L-band = 23.98 cm, and P-band = 68.13 cm. The data are processed to four-looks and have a spatial resolution of 10 m and a swath width of 12 km. The AIRSAR data used in this study were collected as part of the Geologic Remote Sensing Field Experiment (GRSFE) over Death Valley on 9/14/89. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is a NASA/JPL instrument that flies in an ER-2 aircraft at an altitude of 20 km. AVIRIS uses four spectrometers to collect data in 224 spectral channels from 0.4 micrometer to 2.45 micrometer. The width of each spectral band is approximately 10 nm. AVIRIS collects data with a swath width of 11 km and a pixel size of 20 m. The AVIRIS data used in this study were collected over Death Valley on 5/31/92.

  14. Land subsidence in the San Joaquin Valley, California, as of 1980

    USGS Publications Warehouse

    Ireland, R.L.; Poland, J.F.; Riley, F.S.

    1982-01-01

    Land subsidence due to ground-water overdraft in the San Joaquin Valley began in the mid-1920 's and continued at alarming rates until surface was imported through major canals and aqueducts in the 1950 's and late 1960's. In areas where surface water replaced withdrawal of ground-water, water levels in the confined system rose sharply and subsidence slowed. In the late 1960 's and early 1970 's water levels in wells recovered to levels of the 1940 's and 1950 's throughout most of the western and southern parts of the Valley, in response to the importation of surface water through the California aqueduct. During the 1976-77 drought data collected at water-level and extensometer sites showed the effect of heavy demand on the ground-water resevoir. With the ' water of compaction ' gone, artesian head declined 10 to 20 times as fast as during the first cycle of long-term drawdown that ended in the late 1960's. In the 1978-79 water levels recovered to or above the 1976 pre-drought levels. The report suggests continued monitoring of land subsidence in the San Joaquin Valley. (USGS)

  15. Aeromagnetic map of the Death Valley ground-water model area, Nevada and California

    SciTech Connect

    Ponce, D.A.; Blakely, R.J.

    2002-03-12

    This aeromagnetic map of the Death Valley ground-water model area was prepared from numerous separate aeromagnetic surveys that were gridded, merged, and described by Hildenbrand and Kucks (1988) and by McCafferty and Grauch (1997). These data are available in grid format from the EROS Data Center, U.S. Geological Survey, Sioux Falls, South Dakota, 57198, and from the National Geophysical Data Center, 325 Broadway, E/GC4, Boulder, Colo., 80303. Magnetic investigations of the Death Valley ground-water basin are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency Agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwest Nevada and adjacent parts of California (Blakely and others, 2000b). The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W.

  16. A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

    SciTech Connect

    Faunt, C.C.; D`Agnese, F.A.; Turner, A.K.

    1997-12-31

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km{sup 2} along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing.

  17. Climate Extremes and Adaptive Flood Management in the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Munevar, A.; Das, T.

    2014-12-01

    Current evaluations of Central Valley, California flood control improvements are based on climate and hydrologic conditions that occurred over the past 100 years. This historical period includes significant flood events caused by intense precipitation, rapid snowmelt, and watershed conditions that, in combination, result in the hydrologic conditions that have shaped the current flood infrastructure and management. Future climate projections indicate the potential for increased flood peak flows and flood volumes in the Central Valley that will likely exceed the current capacity of existing flood control systems. Preliminary estimates of potential changes in flood flows have been developed for all the major watersheds in the Central Valley through the use of regionally downscaled climate projections and hydrologic modeling. Results suggest increasing flood risks that are dependent on spatial climate change patterns, individual watershed characteristics, and existing infrastructure investments. In many areas, the increasing flood risks cannot be managed through traditional flood infrastructure alone, and more adaptive measures are needed to improve resilience under climate extremes. Planning approaches are being applied to consider the full range of flood risks, and include tiered interventions for events beyond the floods-of-record. The on-going flood risk planning efforts demonstrate new, and sensible approaches toward improving resilience for uncertain and evolving climate extremes.

  18. Stormflow chemistry in the Santa Ana River below Prado Dam and at the diversion downstream from Imperial Highway, southern California, 1995-98

    USGS Publications Warehouse

    Izbicki, John A.; Mendez, Gregory O.; Burton, Carmen A.

    2000-01-01

    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 considered a source of 'high-quality' water suitable for use as a source of ground-water recharge. To test this assumption, stormflow samples were collected at two locations--below Prado Dam and at the diversion point downstream from Imperial Highway--for 12 winter storms between 1995 and 1998. Nitrate concentrations decreased during stormflow from a median concentration of 7.8 milligrams per liter in base flow to concentrations less than 1 milligram per liter in some large storms. Concentrations of chemically reduced forms of nitrogen (nitrite, ammonia, and organic nitrogen) increased during stormflow and are the predominant forms of nitrogen in large stormflows. Dissolved organic carbon (DOC) concentrations increased from a median concentration of 4.6 milligrams per liter in base flow to more than 20 milligrams per liter in some stormflows. Concentrations of DOC were especially high during the first storm of the rainy season, and large increases in DOC concentrations were measured even as a result of small early season storms that did not cause large increases in streamflow. DOC present during early season stormflow had less ultraviolet absorbance at 254 nanometers (UV254 ) per unit of carbon than did DOC from late season stormflows. DOC in water held in storage behind Prado Dam had the highest UV254 absorbance per unit of carbon. Maximum pesticide concentrations in stormflow did not exceed U.S. Environmental Protection Agency Maximum Contaminant Levels. Most pesticide concentrations were less than 1 microgram per liter and less than the detection limits obtained using standard

  19. Dabbling duck harvest dynamics in the Central Valley of California--implications for recruitment

    USGS Publications Warehouse

    Miller, M.R.; Beam, J.; Connelly, D.P.

    1988-01-01

    Age and sex ratios and body weights were obtained for northern pintails (Anas acuta), mallards (A. platyrhynchos), American wigeon (A. americana), green-winged teal (A. crecca), and northern shovelers (A. clypeata) shot at Mendota State Wildlife Area in the San Joaquin Valley (SANJV) and at Sacramento National Wildlife Refuge in the Sacramento Valley (SACV) during 1982-83 and 1983-84. Age ratios were determined for pintails at four locations during 1980-83. Cooperative Waterfowl Parts Collection Survey (1982-84; U.S. Fish and Wildlife Service) and California preseason-banding data (1973-77, for mallards and pintails) also were used to measure age ratios of the California harvest. Harvest rate (ducks shot per day) was obtained and summed from all SACV and SANJV public hunting areas in 1982-84. All species except female wigeon and adult female mallards lost weight between October and January. Except for wigeon, harvest rate was high in October when hunting began. Harvest rates were low in November and December but rose markedly in January in the SACV for all species and for all except pintails in the SANJV. Proportion of adults in the bag as measured by all methods increased progressively through the hunting season. Proportion of adults in the harvest was higher in 1982-83 than in 1983-84 and was greater in the SACV than the SANJV both years for most species. Adult females formed a small component of total kill but 50% or more of female kill. The harvest of pintails at a SACV and a SANJV location consistently contained about half as many immatures per adult as that at two other California locations for 1980-83. The substantial harvest of adults in January eliminates the most productive breeders from the population. Thus, winter hunting mortality may influence age composition of the spring flight and, hence, recruitment potential of the breeding population.

  20. Integrated Economic Modeling of Water Supply-Quality Tradeoffs: An Application to the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Bair, L.; MacEwan, D.

    2015-12-01

    Sustainable water management in the San Joaquin Valley, California involves the complex interaction of agricultural, municipal and industrial, and environmental water use. California's Sustainable Groundwater Management Act (SGMA) of 2014 requires groundwater basins historically in a state of overdraft to bring the basin into a sustainable balance over the next 20 years. In addition to limiting groundwater availability, implementation of the SGMA has implications for surface and groundwater quality. Availability of groundwater influences agricultural production decisions, resulting in variation in agricultural runoff and changes to surface and groundwater quality. Changes in water quality have economic impacts on agricultural production and urban water use. These impacts range from reductions in crop productivity to costs of alternative water supplies to amend declining water quality. We model the impact of agricultural and urban groundwater availability on surface water quality within the San Joaquin and Kings River watersheds in the Central Valley, downriver to the Mendota Pool by linking SWAT (Soil and Water Assessment Tool), an integrated water supply-quality model, with SWAP (Statewide Agricultural Production Model), a regional agricultural economics model. The integrated model specifies the relationship between changes in groundwater availability, groundwater elevation, agricultural production, and surface water quality. We link the SWAT-SWAP model output to urban and agricultural economic loss calculations that are a function of water quality. Model results demonstrate the economic tradeoffs between groundwater availability and water quality. The results of the integrated economic water supply-quality model are applicable to other regions in California and elsewhere that contain complex water supply-quality interactions.

  1. Analytical results and sample locality map for rock, stream-sediment, and soil samples, Northern and Eastern Coloado Desert BLM Resource Area, Imperial, Riverside, and San Bernardino Counties, California

    USGS Publications Warehouse

    King, Harley D.; Chaffee, Maurice A.

    2000-01-01

    INTRODUCTION In 1996-1998 the U.S. Geological Survey (USGS) conducted a geochemical study of the Bureau of Land Management's (BLM) 5.5 million-acre Northern and Eastern Colorado Desert Resource Area (usually referred to as the NECD in this report), Imperial, Riverside, and San Bernardino Counties, southeastern California (figure 1). This study was done in support of the BLM's Coordinated Management Plan for the area. This report presents analytical data from this study. To provide comprehensive coverage of the NECD, we compiled and examined all available geochemical data, in digital form, from previous studies in the area, and made sample-site plots to aid in determining where sample-site coverage and analyses were sufficient, which samples should be re-analyzed, and where additional sampling was needed. Previous investigations conducted in parts of the current study area included the National Uranium Resource Evaluation (NURE) program studies of the Needles and Salton Sea 1? x 2? quadrangles; USGS studies of 12 BLM Wilderness Study Areas (WSAs) (Big Maria Mountains, Chemehuevi Mountains, Chuckwalla Mountains, Coxcomb Mountains, Mecca Hills, Orocopia Mountains, Palen-McCoy, Picacho Peak, Riverside Mountains, Sheephole Valley (also known as Sheep Hole/Cadiz), Turtle Mountains, and Whipple Mountains); and USGS studies in the Needles and El Centro 1? x 2? quadrangles done during the early 1990s as part of a project to identify the regional geochemistry of southern California. Areas where we did new sampling of rocks and stream sediments are mainly in the Chocolate Mountain Aerial Gunnery Range and in Joshua Tree National Park, which extends into the west-central part of the NECD, as shown in figure 1 and figure 2. This report contains analytical data for 132 rock samples and 1,245 stream-sediment samples collected by the USGS, and 362 stream-sediment samples and 189 soil samples collected during the NURE program. All samples are from the Northern and Eastern Colorado

  2. Terrestrial Cosmogenic-Nuclide Dating of Alluvial Fans in Death Valley, California

    USGS Publications Warehouse

    Machette, Michael N.; Slate, Janet L.; Phillips, Fred M.

    2008-01-01

    We have used terrestrial cosmogenic nuclides (TCN) to establish the age of some of the most extensive Quaternary alluvial fans in Death Valley, California. These intermediate-age alluvial fans are most extensive on the western side of the valley, where tectonic deformation is considerably less pronounced than on the eastern side of the valley. These fans are characterized by a relatively smooth, densely packed desert pavement formed by well-varnished (blackened) clasts. These surfaces have been mapped as the Q2 gravel by previous workers and as unit Qai (intermediate age) by us. However, the intermediate-age gravels probably contain multiple subunits, as evidenced by slight differences in morphologic expression, soil formation, and inset geomorphic relations. The TCN technique used herein sums the cosmogenic 36Cl in approximately 2.5-meter-deep profiles through soil and host alluvium, thus avoiding some of the problems associated with the more typical surface-exposure dating of boulders or smaller clasts. Our TCN 36Cl dating of 12 depth profiles indicates that these intermediate-age (Qai) alluvial fans range from about 100 to 40 kilo-annum (ka), with a mean age of about 70 ka. An alternative interpretation is that alluvial unit Qai was deposited in two discrete episodes from 90 to 80 ka and from 60 to 50 ka, before and after MIS (marine oxygen-isotope stage) 4 (respectively). Without an intermediate-age unit, such as MIS 4 lake deposits, we can neither disprove nor prove that Qai was deposited in two discrete intervals or over a longer range of time. Thus, in Death Valley, alluvial unit Qai largely brackets MIS 4, which is not associated with a deep phase of Lake Manly. These Qai fans extend to elevations of about -46 meters (150 feet below sea level) and have not been transgressed by Lake Manly, suggesting that MIS 4 or MIS 2 lakes were rather shallow in Death Valley, perhaps because they lacked inflow from surface runoff of the Sierra Nevada drainages through

  3. High-resolution three-dimensional imaging and analysis of rock falls in Yosemite valley, California

    USGS Publications Warehouse

    Stock, Gregory M.; Bawden, G.W.; Green, J.K.; Hanson, E.; Downing, G.; Collins, B.D.; Bond, S.; Leslar, M.

    2011-01-01

    We present quantitative analyses of recent large rock falls in Yosemite Valley, California, using integrated high-resolution imaging techniques. Rock falls commonly occur from the glacially sculpted granitic walls of Yosemite Valley, modifying this iconic landscape but also posing signifi cant potential hazards and risks. Two large rock falls occurred from the cliff beneath Glacier Point in eastern Yosemite Valley on 7 and 8 October 2008, causing minor injuries and damaging structures in a developed area. We used a combination of gigapixel photography, airborne laser scanning (ALS) data, and ground-based terrestrial laser scanning (TLS) data to characterize the rock-fall detachment surface and adjacent cliff area, quantify the rock-fall volume, evaluate the geologic structure that contributed to failure, and assess the likely failure mode. We merged the ALS and TLS data to resolve the complex, vertical to overhanging topography of the Glacier Point area in three dimensions, and integrated these data with gigapixel photographs to fully image the cliff face in high resolution. Three-dimensional analysis of repeat TLS data reveals that the cumulative failure consisted of a near-planar rock slab with a maximum length of 69.0 m, a mean thickness of 2.1 m, a detachment surface area of 2750 m2, and a volume of 5663 ?? 36 m3. Failure occurred along a surfaceparallel, vertically oriented sheeting joint in a clear example of granitic exfoliation. Stress concentration at crack tips likely propagated fractures through the partially attached slab, leading to failure. Our results demonstrate the utility of high-resolution imaging techniques for quantifying far-range (>1 km) rock falls occurring from the largely inaccessible, vertical rock faces of Yosemite Valley, and for providing highly accurate and precise data needed for rock-fall hazard assessment. ?? 2011 Geological Society of America.

  4. Paleontologic investigations of the uppermost Santa Susana Formation, south side of Simi Valley, southern California

    SciTech Connect

    Squires, R.L. )

    1991-02-01

    Strata assignable to the provincial macroinvertebrate Meganos stage, equivalent to the calcareous nannofossil CP8 zone (late Paleocene) to CP9 zone (early Eocene), are uncommon on the Pacific coast of North America. This stage has been recognized in southern California only in the uppermost Santa Susana Formation, north side of Simi Valley. Although early workers reported meganos stage strata from the south side of Simi Valley, most of these deposits have since been assigned to younger or older stages. Intensive collecting by the author now proves that Meganos stage fossils are present in the upper 100 m of the Santa Susana Formation on the south side of the Simi Valley, east of the Runkle Canyon fault. This 100-m-thick interval consists of gray, very fine-grained sandstone that has a gradational lithology from the underlying gray mudstone. Calcareous nannofossils were found only near the bottom of the 100-m-thick interval, and they are suggestive of the late Paleocene Discoaster multiradiatus (CP8) zone. Rare, macrofossil-bearing lenses near the bottom of the 100-m-thick interval contain the solitary coral Trochocyathus zitteli, the gastropods Turritella subuvasana and the Velates californicus( ), and the bivalve Fimbria susanensis. Sparsely occurring, macrofossil-bearing lenses in the upper 20 m of the 100-m-thick- interval contain the colonial coral Archohelia clarki and the gastropod Turritella andersoni susanae (= T. andersoni n. subsp. of authors). Turritella andersoni susanae indicates the early Eocene part of the Meganoz stage because it is found just above the earliest Eocene Discoaster diastypus (CP9) zone in the upper Santa Susana Formation on the north side of Simi Valley.

  5. Evidence for Groundwater Contamination Vulnerability in California?s Central Valley

    SciTech Connect

    Moran, J E; Leif, R; Esser, B K; Singleton, M J

    2005-12-13

    The California Water Resources Control Board, in collaboration with the US Geological Survey and Lawrence Livermore National Laboratory, has implemented a program to assess the susceptibility of groundwater resources. Advanced techniques such as groundwater age dating using the tritium-helium method, extensive use of oxygen isotopes of the water molecule ({delta}{sup 18}O) for recharge water provenance, and analysis of common volatile organic compounds (VOCs) at ultra-low levels are applied with the goal of assessing the contamination vulnerability of deep aquifers, which are frequently used for public drinking water supply. Over 1200 public drinking water wells have been tested to date, resulting in a very large, tightly spaced collection of groundwater ages in some of the heavily exploited groundwater basins of California. Smaller scale field studies that include shallow monitoring wells are aimed at assessing the probability that nitrate will be transported to deep drinking water aquifers. When employed on a basin-scale, groundwater ages are an effective tool for identifying recharge areas, defining flowpaths, and determining the rate of transport of water and entrained contaminants. De-convolution of mixed ages, using ancillary dissolved noble gas data, gives insight into the water age distribution drawn at a well, and into the effective dilution of contaminants such as nitrate at long-screened production wells. In combination with groundwater ages, low-level VOCs are used to assess the impact of vertical transport. Special studies are focused on the fate and transport of nitrate with respect to vulnerability of aquifers in agricultural and formerly agricultural areas.

  6. Drought resilience of the California Central Valley surface-groundwater-conveyance system

    SciTech Connect

    Miller, N.L.; Dale, L.L.; Brush, C.; Vicuna, S.; Kadir, T.N.; Dogrul, E.C.; Chung, F.I.

    2009-05-15

    A series of drought simulations were performed for the California Central Valley using computer applications developed by the California Department of Water Resources and historical datasets representing a range of droughts from mild to severe for time periods lasting up to 60 years. Land use, agricultural cropping patterns, and water demand were held fixed at the 2003 level and water supply was decreased by amounts ranging between 25 and 50%, representing light to severe drought types. Impacts were examined for four hydrologic subbasins, the Sacramento Basin, the San Joaquin Basin, the Tulare Basin, and the Eastside Drainage. Results suggest the greatest impacts are in the San Joaquin and Tulare Basins, regions that are heavily irrigated and are presently overdrafted in most years. Regional surface water diversions decrease by as much as 70%. Stream-to-aquifer flows and aquifer storage declines were proportional to drought severity. Most significant was the decline in ground water head for the severe drought cases, where results suggest that under these scenarios the water table is unlikely to recover within the 30-year model-simulated future. However, the overall response to such droughts is not as severe as anticipated and the Sacramento Basin may act as ground-water insurance to sustain California during extended dry periods.

  7. Rockfall hazard and risk assessment in the Yosemite Valley, California, USA

    USGS Publications Warehouse

    Guzzetti, F.; Reichenbach, P.; Wieczorek, G.F.

    2003-01-01

    Rock slides and rock falls are the most frequent types of slope movements in Yosemite National Park, California. In historical time (1857-2002) 392 rock falls and rock slides have been documented in the valley, and some of them have been mapped in detail. We present the results of an attempt to assess rock fall hazards in the Yosemite Valley. Spatial and temporal aspects of rock falls hazard are considered. A detailed inventory of slope movements covering the 145-year period from 1857 to 2002 is used to determine the frequency-volume statistics of rock falls and to estimate the annual frequency of rock falls, providing the temporal component of rock fall hazard. The extent of the areas potentially subject to rock fall hazards in the Yosemite Valley were obtained using STONE, a physically-based rock fall simulation computer program. The software computes 3-dimensional rock fall trajectories starting from a digital elevation model (DEM), the location of rock fall release points, and maps of the dynamic rolling friction coefficient and of the coefficients of normal and tangential energy restitution. For each DEM cell the software calculates the number of rock falls passing through the cell, the maximum rock fall velocity and the maximum flying height. For the Yosemite Valley, a DEM with a ground resolution of 10 ?? 10 m was prepared using topographic contour lines from the U.S. Geological Survey 1:24 000-scale maps. Rock fall release points were identified as DEM cells having a slope steeper than 60??, an assumption based on the location of historical rock falls. Maps of the normal and tangential energy restitution coefficients and of the rolling friction coefficient were produced from a surficial geologic map. The availability of historical rock falls mapped in detail allowed us to check the computer program performance and to calibrate the model parameters. Visual and statistical comparison of the model results with the mapped rock falls confirmed the accuracy of

  8. Coho Salmon Habitat in a Changing Environment-Green Valley Creek, Graton, California

    NASA Astrophysics Data System (ADS)

    O'Connor, M. D.; Kobor, J. S.; Sherwood, M. N.

    2013-12-01

    Green Valley Creek (GVC) is a small (101 sq km) aquatic habitat refugium in the Russian River watershed (3,840 sq km) in coastal northern California. Coho salmon (Onchorhynchus kisutch) is endangered per the Federal Endangered Species Act, and GVC is one stream where coho have persisted. Fish surveys in GVC have found high species diversity, growth rates, and over-summer survival. The upper portion of GVC comprises a principal tributary (20 sq km) that provides spawning and rearing habitat for coho. The second principal tributary, Atascadero Creek, is comparable in size, but has few fish. Atascadero Creek and lower GVC have broad, densely vegetated floodplains. A Recovery Plan for the Central Coastal California coho Evolutionarily Significant Unit has been developed by the National Marine Fisheries Service (NMFS), which applies to the Russian River and its tributaries. Cooperative research regarding fish populations and habitat, a captive breeding and release program for native coho salmon, and efforts to plan for and restore habitat are ongoing. These regional efforts are particularly active in GVC, and participants include NMFS, the California Department of Fish and Wildlife, the Gold Ridge Resource Conservation District, the California Coastal Conservancy, the University of California Cooperative Extension, and the National Fish and Wildlife Foundation, among others. Our research focuses on hydrologic, geomorphic and hydrogeologic characteristics of the watershed in relation to aquatic habitat. Natural watershed factors contributing to habitat for coho include proximity to the coastal summer fog belt with cool temperatures, the Wilson Grove Formation aquifer that maintains dry season stream flow, and structural geology favorable for active floodplain morphology. Human impacts include water use and agriculture and rural residential development. Historic human impacts include stream clearing and draining of wetlands and floodplain for agriculture, which likely

  9. Assessment of the importance of alfalfa to the epidemiology of xylellae diseases in the San Joaquin Valley of California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The role of alfalfa in the epidemiology of xylellae diseases in the San Joaquin Valley of California was assessed. Alfalfa was investigated as it is a known host of Xylella fastidiosa and often harbors large populations of a native vector, Draeculacephala minerva. Laboratory inoculation of fourtee...

  10. Distribution of Glyphosate-Resistant Horseweed (Conyza Canadensis) and Relationship to Cropping Systems in the Central Valley of California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Horseweed is an increasing problem in perennial crops and non-crop areas of the Central Valley of California. Similar to the situation in glyphosate-tolerant crops in other regions, glyphosate-based weed management strategies in perennial crops and non-crop areas have resulted in selection of a gly...

  11. Late Cenozoic geology and lacustrine history of Searles Valley, Inyo and San Bernardino Counties, California

    NASA Astrophysics Data System (ADS)

    Nathenson, M.; Smith, G. I.; Robinson, J. E.; Stauffer, P. H.; Zigler, J. L.

    2010-12-01

    George Smith’s career-long study of the surface geology of the Searles Valley was recently published by the USGS (Smith, 2009, online and printed). The co-authors of this abstract are the team responsible for completing the publication from the original materials. Searles Valley is an arid, closed basin lying 70 km east of the south end of the Sierra Nevada, California. During those parts of late Pliocene and Pleistocene time when precipitation and runoff from the east side of the Sierra Nevada into the Owens River were much greater than at present, a chain of as many as five large lakes was created, of which Searles Lake was third. The stratigraphic record left in Searles Valley when that lake expanded, contracted, or desiccated is fully revealed by cores taken from beneath the surface of Searles (dry) Lake and partly recorded by sediments cropping out around the edge of the valley. Although this outcrop record is discontinuous, it provides direct evidence of the lake’s water depths during each expansion, which the subsurface record does not. Maximum-depth lakes rose to the 2,280-ft (695 m) contour, the level of the spillway that led overflowing waters to Panamint Valley; that spillway is about 660 ft (200 m) above the present dry-lake surface. Most of this study concerns sediments of the newly described Searles Lake Formation, whose deposition spanned the period between about 150 ka and 2 ka. The outcrop record is documented in six geologic maps (scales: 1:50,000 and 1:10,000). The Searles Lake Formation is divided into seven main units. The depositional intervals of the units that make up the Searles Lake Formation are determined primarily by correlation with subsurface deposits that are dated by radiocarbon ages on organic carbon and U-series dates on salts. Shorelines, the most obvious geologic expressions of former lakes, are abundant around Searles Valley. Erosional shorelines have cut as much as 100 m into brecciated bedrock; depositional shorelines

  12. SRTM Perspective View with Landsat Overlay: Caliente Range and Cuyama Valley, California

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Before the arrival of Europeans, California's Cuyama Valley was inhabited by Native Americans who were culturally and politically tied to the Chumash tribes of coastal Santa Barbara County. Centuries later, the area remains the site of noted Native American rock art paintings. In the 1800s, when Europeans established large cattle and horse-breeding ranches in the valley, the early settlers reported the presence of small villages along the Cuyama River. This perspective view looks upstream toward the southeast through the Cuyama Valley. The Caliente Range, with maximum elevations of 1,550 meters (5,085 feet), borders the valley on the left. The Cuyama River, seen as a bright meandering line on the valley floor, enters the valley from headwaters more than 2,438 meters (8,000 feet) above sea level near Mount Abel and flows 154 kilometers (96 miles) before emptying into the Pacific Ocean. The river's course has been determined in large part by displacement along numerous faults.

    Today, the Cuyama Valley is the home of large ranches and small farms. The area has a population of 1,120 and is more than an hour and a half drive from the nearest city in the county.

    This image was generated by draping an enhanced Landsat satellite image over elevation data from the Shuttle Radar Topography Mission (SRTM). Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors approximate natural colors.

    The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM

  13. Kinematics of the Eastern California shear zone: Evidence for slip transfer from Owens and Saline Valley fault zones to Fish Lake Valley fault zone

    USGS Publications Warehouse

    Reheis, M.C.; Dixon, T.H.

    1996-01-01

    Late Quaternary slip rates and satellite-based geodetic data for the western Great Basin constrain regional fault-slip distribution and evolution. The geologic slip rate on the Fish Lake Valley fault zone (the northwest extension of the Furnace Creek fault zone) increases northward from about 3 to 5 mm/yr, in agreement with modeled geodetic data. The increase coincides with the intersections of the Deep Springs fault, connected to the Owens Valley fault zone, and of other faults connected to the Saline Valley fault. The combined geologic and geodetic data suggest that (1) the northwest-striking faults of the Eastern California shear zone north of the Garlock fault are connected by north- to northeast-striking normal faults that transfer slip in a series of right steps, and (2) the amount and distribution of slip among the many faults of this broad, complex plate boundary have changed through time.

  14. Irrigation water supply and demand data for 1976, 1980, and 1984 for the western San Joaquin Valley, California

    USGS Publications Warehouse

    Templin, W.E.; Haltom, T.C.

    1994-01-01

    This report presents the irrigation water supply and demand data for 1976, 1980, and 1984 for 32 water districts in the western San Joaquin Valley, California. Data are provided for each water district or each of the three years if the data were available. The complete data base is given by water district or each township, range, and section in the rectangular system for the subdivision of public lands. These data were complied for use in a ground- water-flow model, compilation of a water-budget, and use by the San Joaquin Valley Drainage Program in a study of water management in the western San Joaquin Valley, California. The data are presented in a computer-readable format to improve data utilization and to condense the information so that it can be more readily distributed to users.

  15. Groundwater quality in the Madera and Chowchilla subbasins of the San Joaquin Valley, California

    USGS Publications Warehouse

    Shelton, Jennifer L.; Fram, Miranda S.; Belitz, Kenneth

    2013-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s untreated groundwater quality and increases public access to groundwater-quality information. The Madera and Chowchilla subbasins of the San Joaquin Valley constitute one of the study units being evaluated. The Madera-Chowchilla study unit is about 860 square miles and consists of the Madera and Chowchilla groundwater subbasins of the San Joaquin Valley Basin (California Department of Water Resources, 2003; Shelton and others, 2009). The study unit has hot, dry summers and cool, moist winters. Average annual rainfall ranges from 11 to 15 inches, most of which occurs between November and February. The main surface-water features in the study unit are the San Joaquin, Fresno, and Chowchilla Rivers, and the Madera and Chowchilla canals. Land use in the study unit is about 69 percent (%) agricultural, 28% natural (mainly grasslands), and 3% urban. The primary crops are orchards and vineyards. The largest urban area is the city of Madera. The primary aquifer system is defined as those parts of the aquifer corresponding to the perforated intervals of wells listed in the California Department of Public Health (CDPH) database. In the Madera-Chowchilla study unit, these wells typically are drilled to depths between 200 and 800 feet, consist of a solid casing from land surface to a depth of about 140 to 400 feet, and are perforated below the solid casing. Water quality in the primary aquifer system may differ from that in the shallower and deeper parts of the aquifer system. The primary aquifer system in the study unit consists of Quaternary-age alluvial-fan and fluvial deposits that were formed by the rivers draining the Sierra Nevada. Sediments consist of gravels, sands

  16. Land use investigations in the central valley and central coastal test sites, California

    NASA Technical Reports Server (NTRS)

    Estes, J. E.

    1973-01-01

    The Geography Remote Sensing Unit (GRSU) at the University of California, Santa Barbara is responsible for investigations with ERTS-1 data in the Central Coastal Zone and West Side of the San Joaquin Valley. The nature of investigative effort involves the inventory, monitoring, and assessment of the natural and cultural resources of the two areas. Land use, agriculture, vegetation, landforms, geology, and hydrology are the principal subjects for attention. These parameters are the key indicators of the dynamically changing character of the areas. Monitoring of these parameters with ERTS-1 data will provide the techniques and methodologies required to generate the information needed by federal, state, county, and local agencies to assess change-related phenomena and plan for management and development.

  17. Impacts of changing irrigation practices on waterfowl habitat use in the southern San Joaquin Valley, California

    USGS Publications Warehouse

    Barnum, D.A.; Euliss, N. H ., Jr.

    1991-01-01

    We used diurnal aerial census data to examine habitat use patterns of ducks wintering in the southern San Joaquin Valley, California from 1980-87. We calculated densities (birds/ha) for the northern pintail (Anas acuta), mallard (A. platyrhynchos), green-winged teal (A. crecca), cinnamon teal (A. cyanoptera), shoveler (A. clypeata), ruddy duck (Oxyura jamaicensis), and total ducks in each of 5 habitats. Densities of pintail and total ducks were greater in September than in other months. From October through January, density of teal and total ducks was greatest on Kern National Wildlife Refuge (NWR). Densities of ruddy duck and pintail were greatest on agricultural drainwater evaporation ponds and preirrigated cropland, respectively.

  18. Precipitation forecast using artificial neural networks. An application to the Guadalupe Valley, Baja California, Mexico

    NASA Astrophysics Data System (ADS)

    Herrera-Oliva, C. S.

    2013-05-01

    In this work we design and implement a method for the determination of precipitation forecast through the application of an elementary neuronal network (perceptron) to the statistical analysis of the precipitation reported in catalogues. The method is limited mainly by the catalogue length (and, in a smaller degree, by its accuracy). The method performance is measured using grading functions that evaluate a tradeoff between positive and negative aspects of performance. The method is applied to the Guadalupe Valley, Baja California, Mexico. Using consecutive intervals of dt=0.1 year, employing the data of several climatological stations situated in and surrounding this important wine industries zone. We evaluated the performance of different models of ANN, whose variables of entrance are the heights of precipitation. The results obtained were satisfactory, except for exceptional values of rain. Key words: precipitation forecast, artificial neural networks, statistical analysis

  19. Structural and lithographic study of northern coast ranges and Sacramento Valley, California

    NASA Technical Reports Server (NTRS)

    Rich, E. I. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. The analysis of the ERTS data has disclosed three potentially important linear systems within the northern coast ranges and Sacramento Valley, California. A preliminary geomorphic analysis of the northern coast ranges discloses that the geomorphic characteristics of the area underlain by the Coastal system are much different from those associated with the Central system in the core of the Coast Ranges. Within the Coastal system, or Coastal belt, the drainage networks are moderately fine-textured and have moderately high density. The area associated with the Central system seems to be underlain by an heterogeneous assemblage of rock types which vary in their resistance to erosion. The boundary between the Coastal and Central geomorphic regions is poorly defined and, in a few places, the two regions can be separated only approximately.

  20. Geohydrologic aspects of water-quality problems of the San Joaquin Valley, California

    USGS Publications Warehouse

    Deverel, S.J.

    1988-01-01

    Salinity and selenium concentrations in shallow ground water of the western San Joaquin Valley, California, are related to the geomorphology and hydrology of the alluvial fans. High salinity and selenium concentrations are associated with ephemeral-stream deposits. Low salinity and selenium concentrations are associated with intermittent-stream deposits, which represent the major alluvial fans of the area. The highest salinity and selenium concentrations at the margins of the alluvial fans are the result of evaporation and evapotranspiration of shallow ground water, as indicated by oxygen- and hydrogen-isotopic data. The extent and direction of movement of saline ground water to drain laterals in agricultural fields are influenced by the time since installation of the drainage system, drain lateral spacing, and the regional ground-water-flow system.

  1. Biogeochemical cycling of selenium in the San Joaquin Valley, California, USA

    NASA Astrophysics Data System (ADS)

    Presser, Theresa S.; Ohlendorf, Harry M.

    1987-11-01

    Subsurface agricultural drainage waters from western San Joaquin Valley, California, were found to contain elevated concentrations of the element selenium in the form of selenate. In 1978, these drainage waters began to replace previous input to Kesterson Reservoir, a pond system within Kesterson National Wildlife Refuge; this substitution was completed by 1982. In the 1983 nesting season, unusual rates of deformity and death in embryos and hatchlings of wild aquatic birds (up to 64% of eared grebe and American coot nests) occurred at the refuge and were attributed to selenium toxicosis. Features necessary for contamination to have taken place included geologic setting, climate, soil type, availability of imported irrigation water, type of irrigation, and the unique chemical properties of selenium. The mechanisms of biogeochemical cycling raise questions about other ecosystems and human exposure.

  2. Potential hazards from floodflows in Wildrose Canyon, Death Valley National Monument, California-Nevada

    USGS Publications Warehouse

    Crippen, John R.

    1981-01-01

    Wildrose Canyon, in the western slopes of the Panamint Mountains , is a well-traveled route in Death Valley National Monument and is a scenic area often visited for its own sake. It is an arid region that is subject to flash flooding. Although such flooding is infrequent, when it occurs in the steep, narrow canyon within which the road lies, the flow of water and accompanying debris may be hazardous to life and to any obstacle in its path. Historical records of amounts of rainfall and floodflow in the area are sparse, but data from the basin and from similar areas in the desert mountains of southern California are sufficient to provide a basis for estimates of the degree of hazard. Potential hazards from floodflows are defined for Wildrose Canyon and its nearby approach routes. (USGS)

  3. Biogeochemical cycling of selenium in the San Joaquin Valley, California, USA

    USGS Publications Warehouse

    Presser, T.S.; Ohlendorf, H.M.

    1987-01-01

    Subsurface agricultural drainage waters from western San Joaquin Valley, California, were found to contain elevated concentrations of the element selenium in the form of selenate. In 1978, these drainage waters began to replace previous input to Kesterson Reservoir, a pond system within Kesterson National Wildlife Refuge; this substitution was completed by 1982. In the 1983 nesting season, unusual rates of deformity and death in embryos and hatchlings of wild aquatic birds (up to 64% of eared grebe and American coot nests) occurred at the refuge and were attributed to selenium toxicosis. Features necessary for contamination to have taken place included geologic setting, climate, soil type, availability of imported irrigation water, type of irrigation, and the unique chemical properties of selenium. The mechanisms of biogeochemical cycling raise questions about other ecosystems and human exposure.

  4. Comparison of Summer and Winter California Central Valley Aerosol Distributions from Lidar and MODIS Measurements

    NASA Technical Reports Server (NTRS)

    Lewis, Jasper R., Jr.; DeYoung, Russell J.; Chu, D. Allen

    2010-01-01

    Aerosol distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2008. While the PM2.5 concentration is highest in the winter, the aerosol optical depth measured from MODIS is highest in the summer. A seasonal comparison shows that PM2.5 in the winter can exceed summer PM2.5 by 55%, while summer AOD exceeds winter AOD by 43%. Higher temperatures wildfires in the summer produce elevated aerosol layers that are detected by satellite measurements, but not surface particulate matter monitors. Measurements of the boundary layer height from lidar instruments are necessary to incorporate satellite measurements with air quality measurements.

  5. A conceptual ground-water-quality monitoring network for San Fernando Valley, California

    USGS Publications Warehouse

    Setmire, J.G.

    1985-01-01

    A conceptual groundwater-quality monitoring network was developed for San Fernando Valley to provide the California State Water Resources Control Board with an integrated, basinwide control system to monitor the quality of groundwater. The geology, occurrence and movement of groundwater, land use, background water quality, and potential sources of pollution were described and then considered in designing the conceptual monitoring network. The network was designed to monitor major known and potential point and nonpoint sources of groundwater contamination over time. The network is composed of 291 sites where wells are needed to define the groundwater quality. The ideal network includes four specific-purpose networks to monitor (1) ambient water quality, (2) nonpoint sources of pollution, (3) point sources of pollution, and (4) line sources of pollution. (USGS)

  6. Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California

    USGS Publications Warehouse

    Pigati, J.S.; Miller, D.M.; Bright, J.E.; Mahan, S.A.; Nekola, J.C.; Paces, J.B.

    2011-01-01

    groundwater supported persistent and long-lived desert wetlands in many broad valleys and basins in the American Southwest. When active, these systems provided important food and water sources for local fauna, supported hydrophilic and phreatophytic vegetation, and acted as catchments for eolian and alluvial sediments. Desert wetlands are represented in the geologic record by groundwater discharge deposits, which are also called spring or wetland deposits. Groundwater discharge deposits contain information on the timing and magnitude of past changes in water-table levels and, thus, are a source of paleohydrologic and paleoclimatic information. Here, we present the results of an investigation of extensive groundwater discharge deposits in the central Mojave Desert at Valley Wells, California. We used geologic mapping and stratigraphic relations to identify two distinct wetland sequences at Valley Wells, which we dated using radiocarbon, luminescence, and uranium-series techniques. We also analyzed the sediments and microfauna (ostracodes and gastropods) to reconstruct the specific environments in which they formed. Our results suggest that the earliest episode of high water-table conditions at Valley Wells began ca. 60 ka (thousands of calendar yr B.P.), and culminated in peak discharge between ca. 40 and 35 ka. During this time, cold (4-12 ??C) emergent groundwater supported extensive wetlands that likely were composed of a wet, sedge-rush-tussock meadow mixed with mesic riparian forest. After ca. 35 ka, the water table dropped below the ground surface but was still shallow enough to support dense stands of phreatophytes through the Last Glacial Maximum (LGM). The water table dropped further after the LGM, and xeric conditions prevailed until modest wetlands returned briefly during the Younger Dryas cold event (13.0-11.6 ka). We did not observe any evidence of wet conditions during the Holocene at Valley Wells. The timing of these fluctuations is consistent with

  7. Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California

    USGS Publications Warehouse

    Pigati, Jeffrey S.; Miller, David M.; Bright, Jordon E.; Mahan, Shannon; Nekola, Jeffrey C.; Paces, James B.

    2011-01-01

    During the late Pleistocene, emergent groundwater supported persistent and long-lived desert wetlands in many broad valleys and basins in the American Southwest. When active, these systems provided important food and water sources for local fauna, supported hydrophilic and phreatophytic vegetation, and acted as catchments for eolian and alluvial sediments. Desert wetlands are represented in the geologic record by groundwater discharge deposits, which are also called spring or wetland deposits. Groundwater discharge deposits contain information on the timing and magnitude of past changes in water-table levels and, thus, are a source of paleohydrologic and paleoclimatic information. Here, we present the results of an investigation of extensive groundwater discharge deposits in the central Mojave Desert at Valley Wells, California. We used geologic mapping and stratigraphic relations to identify two distinct wetland sequences at Valley Wells, which we dated using radiocarbon, luminescence, and uranium-series techniques. We also analyzed the sediments and microfauna (ostracodes and gastropods) to reconstruct the specific environments in which they formed. Our results suggest that the earliest episode of high water-table conditions at Valley Wells began ca. 60 ka (thousands of calendar yr B.P.), and culminated in peak discharge between ca. 40 and 35 ka. During this time, cold (4–12 °C) emergent groundwater supported extensive wetlands that likely were composed of a wet, sedge-rush-tussock meadow mixed with mesic riparian forest. After ca. 35 ka, the water table dropped below the ground surface but was still shallow enough to support dense stands of phreatophytes through the Last Glacial Maximum (LGM). The water table dropped further after the LGM, and xeric conditions prevailed until modest wetlands returned briefly during the Younger Dryas cold event (13.0–11.6 ka). We did not observe any evidence of wet conditions during the Holocene at Valley Wells. The timing

  8. Seismic velocity structure and earthquake relocation for the magmatic system beneath Long Valley Caldera, eastern California

    NASA Astrophysics Data System (ADS)

    Lin, Guoqing

    2015-04-01

    A new three-dimensional (3-D) seismic velocity model and high-precision location catalog for earthquakes between 1984 and 2014 are presented for Long Valley Caldera and its adjacent fault zones in eastern California. The simul2000 tomography algorithm is applied to derive the 3-D Vp and Vp/Vs models using first-arrivals of 1004 composite earthquakes obtained from the original seismic data at the Northern California Earthquake Data Center. The resulting Vp model reflects geological structures and agrees with previous local tomographic studies. The simultaneously resolved Vp/Vs model is a major contribution of this study providing an important complement to the Vp model for the interpretation of structural heterogeneities and physical properties in the study area. The caldera is dominated by low Vp anomalies at shallow depths due to postcaldera fill. High Vp and low Vp/Vs values are resolved from the surface to ~ 3.4 km depth beneath the center of the caldera, corresponding to the structural uplift of the Resurgent Dome. An aseismic body with low Vp and high Vp/Vs anomalies at 4.2-6.2 km depth below the surface is consistent with the location of partial melt suggested by previous studies based on Vp models only and the inflation source locations based on geodetic modeling. The Sierran crystalline rocks outside the caldera are generally characterized with high Vp and low Vp/Vs values. The newly resolved velocity model improves absolute location accuracy for the seismicity in the study area and ultimately provides the basis for a high-precision earthquake catalog based on similar-event cluster analysis and waveform cross-correlation data. The fine-scale velocity structure and precise earthquake relocations are useful for investigating magma sources, seismicity and stress interaction and other seismological studies in Long Valley.

  9. Osmotic potential and projected drought tolerance of four phreatophytic shrub species in Owens Valley, California

    USGS Publications Warehouse

    Dileanis, Peter D.; Groeneveld, David P.

    1989-01-01

    A substantial quantity of the water used by plant communities growing on the floor of Owens Valley, California, is derived from a shallow unconfined aquifer. Fluctuations in the water table caused by ground-water withdrawal may result in periods when this water supply is not accessible to plants. The capacity of the plants to adapt to these periods of water loss depends on the availability of water stored in the soil and on physiological characteristics related to the ability of the plants to resist dehydration and wilting. Osmotic adjustment occurred in four phreatophytic shrub species at sites near Bishop, California, where the water table had been lowered by a system of pump-equipped wells installed in the vicinity of vegetation transects. The pressure-volume technique was used to determine osmotic potential and cell-wall elasticity between March 1985 and September 1986 for Atriplex torreyi, Chrysothamnus nauseosus , Sarcobatus verm iculatus , and Artemisia tridentata. Although not usually classified as a phreatophyte, Artemisia tridentata, where it grows on the valley floor, is apparently dependent on the depth to the water table. During late summer, osmotic potentials were 0.37 to 0.41 MPa (megapascal) lower in plants growing on the site where the water table had been lowered compared to an adjacent site where the water table remained at its natural levels. Measurements of soil matric potential at the two sites indicated that osmotic adjustment occurred in response to stress caused by lowering the water table. A theoretical lower limit of osmotic adjustment was determined by comparing initial cell osmotic potentials with initial xylem water potentials. These experimentally derived limits indicated that Atriplex torreyi and S. vermiculatus may maintain leaf cell turgor at significantly lower cell water potentials (about -4.5 MPa) than C. nauseosus or Artemisia tridentata (about -2.5 MPa), which allows them to function in drier soil environments.

  10. Osmotic potential and projected drought tolerance of four phreatophytic shrub species in Owens Valley, California

    USGS Publications Warehouse

    Dileanis, P.D.; Groeneveld, D.P.

    1988-01-01

    A large part of the water used by plant communities growing on the floor of Owens Valley, California, is derived from a shallow unconfined aquifer. Fluctuations in the water table caused by groundwater withdrawal may result in periods when this water supply is not accessible to plants. The capacity of the plants to adapt to these periods of water loss depend on the availability of water stored in the soil and on physiological characteristics related to the ability of the plants to resist dehydration and wilting. Osmotic adjustment occurred in four phreatophytic shrub species at sites near bishop, California, where the water table had been lowered by a system of pump-equipped wells installed in the vicinity of vegetation transects. The pressure-volume techniques was used to determine osmotic potential and cell-wall elasticity between March 1985 and September 1986 for Atriplex torreyi, Chrysothamnus nauseosus , Sarcobatus vermiculatus, and Artemisia tridentata. Although not usually classified as a phreatophyte, Artemisia tridentata, where it grows on the valley floor, is apparently dependent on the depth to the water table. During late summer, osmotic potentials were 0.37 to 0.41 megapascal lower in plants growing on the site where the water table had been lowered compared to an adjacent site where the water table remained at its natural levels. Measurements of soil matric potential at the two sites indicated that osmotic adjustment occurred in response to stress caused by lowering the water table. A theoretical lower limit of osmotic adjustment was determined by comparing initial cell osmotic potentials with initial xylem water potentials. These experimentally derived limits indicated that A. torreyi and S. vermiculatus may maintain leaf cell turgor at significantly lower cell water potentials (about -4.5 megapascals) than C. nauseosus or A. tridentata (about -2.5 megapascals) and allows them to function in dryer soil environments. (Author 's abstract)

  11. Field Scale Groundwater Nitrate Loading Model for the Central Valley, California, 1945-Current

    NASA Astrophysics Data System (ADS)

    Harter, T.; Dzurella, K.; Bell, A.; Kourakos, G.

    2015-12-01

    Anthropogenic groundwater nitrate contamination in the Central Valley aquifer system, California, is widespread, with over 40% of domestic wells in some counties exceeding drinking water standards. Sources of groundwater nitrate include leaky municipal wastewater systems, municipal wastewater recharge, onsite wastewater treatment (septic) systems, atmospheric nitrogen deposition, animal farming, application of organic waste materials (sludge, biosolids, animal manure) to agricultural lands, and synthetic fertilizer. At the site or field scale, nitrogen inputs to the landscape are balanced by plant nitrogen uptake and harvest, atmospheric nitrogen losses, surface runoff of nitrogen, soil nitrogen storage changes, and leaching to groundwater. Irrigated agriculture is a dominant player in the Central Valley nitrogen cycle: The largest nitrogen fluxes are synthetic fertilizer and animal manure applications to cropland, crop nitrogen uptake, and groundwater nitrogen losses. We construct a historic field/parcel scale groundwater nitrogen loading model distinguishing urban and residential areas, individual animal farming areas, leaky wastewater lagoons, and approximately 50 different categories of agricultural crops. For non-agricultural landuses, groundwater nitrate loading is based on reported leaching values, animal population, and human population. For cropland, groundwater nitrate loading is computed from mass balance, taking into account diverse and historically changing management practices between different crops. Groundwater nitrate loading is estimated for 1945 to current. Significant increases in groundwater nitrate loading are associated with the expansion of synthetic fertilizer use in the 1950s to 1970s. Nitrate loading from synthetic fertilizer use has stagnated over the past 20 years due to improvements in nutrient use efficiency. However, an unbroken 60 year exponential increase in dairy production until the late 2000s has significantly impacted the

  12. A late Pliocene to middle Pleistocene pluvial lake in Fish Lake Valley, Nevada and California

    USGS Publications Warehouse

    Reheis, M.C.; Slate, J.L.; Sarna-Wojcicki, A. M.; Meyer, C.E.

    1993-01-01

    The question of whether a pluvial lake existed in Fish Lake Valley, Nevada and California, has been debated for more than 100 yr. New stratigraphic evidence indicates that a lake did exist in this valley at intervals during late Pliocene to middle Pleistocene time. This lake may have drained northward, or it may have been periodically contiguous with a pluvial lake to the north in Columbus Salt Marsh. Proof of the existence of this lake, informally named Pluvial Lake Rennie, is derived from three principal outcrops of shallow-water deposits, two outcrops of deep-water deposits, and several drilling logs. The deposits contain beds of silicic tephra, which provide age control. Pluvial Lake Rennie fluctuated in size and depth beginning prior to 2 Ma and continuing until sometime after 0.77 Ma. At about 0.77 Ma, the lake had a highstand at an elevation of ~1460 m, covered an area of 400-500 km2, and had a maximum depth of ~250 m. The lake level dropped just after the eruption of the Bishop ash, but the lake may have persisted at a lower level until ~0.5 Ma. -from Authors

  13. Predicting Arsenic in Drinking Water Wells of the Central Valley, California.

    PubMed

    Ayotte, Joseph D; Nolan, Bernard T; Gronberg, Jo Ann

    2016-07-19

    Probabilities of arsenic in groundwater at depths used for domestic and public supply in the Central Valley of California are predicted using weak-learner ensemble models (boosted regression trees, BRT) and more traditional linear models (logistic regression, LR). Both methods captured major processes that affect arsenic concentrations, such as the chemical evolution of groundwater, redox differences, and the influence of aquifer geochemistry. Inferred flow-path length was the most important variable but near-surface-aquifer geochemical data also were significant. A unique feature of this study was that previously predicted nitrate concentrations in three dimensions were themselves predictive of arsenic and indicated an important redox effect at >10 μg/L, indicating low arsenic where nitrate was high. Additionally, a variable representing three-dimensional aquifer texture from the Central Valley Hydrologic Model was an important predictor, indicating high arsenic associated with fine-grained aquifer sediment. BRT outperformed LR at the 5 μg/L threshold in all five predictive performance measures and at 10 μg/L in four out of five measures. BRT yielded higher prediction sensitivity (39%) than LR (18%) at the 10 μg/L threshold-a useful outcome because a major objective of the modeling was to improve our ability to predict high arsenic areas. PMID:27399813

  14. Lithology, mineralogy, and paleontology of Quaternary lake deposits in Long Valley Caldera, California

    USGS Publications Warehouse

    Fournier, R.B.

    1989-01-01

    Drill cores and cuttings from two drill holes, about 3 km apart, in Long Valley caldera, Mono County, California, were studied using x-ray diffraction and optical methods. A thick sequence of tuffs and lake sediments was encountered in LVCH-1 (1,000 ft deep) and Republic well 66-29 (6,920 ft deep), drilled in the southeast part of the Long Valley caldera. Ostracods, diatoms, and isotopic data indicate that the sediments and tuffs were deposited in a shallow caldera lake which changed in salinity over time. Conditions ranged from very saline in the older lake to fresh in the youngest. The sequence of secondary minerals from top to bottom is: clinoptilolite, mordenite, analcime, K-feldspar (and albite). In some geothermal systems, this sequence of secondary minerals is a function of temperature; however, the paleontological and isotopic data indicate that the change in secondary minerals with increasing depth is due to the older strata being deposited in a more saline environment. No mineralogical evidence of hydrothermal alteration is present, although the high lithium content of some clays and feldspars and the isotopic composition of some sulfate (gypsum) seems to require a hydrothermal source. (Lantz-PTT)

  15. A summary of ground-water pumpage in the Central Valley, California, 1961-77

    USGS Publications Warehouse

    Diamond, Jonathan; Williamson, A.K.

    1983-01-01

    In the Central Valley of California, a great agricultural economy has been developed in a semiarid environment. This economy is supported by imported surface water and 9 to 15 million acre-feet per year of ground water. Estimates of ground-water pumpage computed from power consumption have been compiled and summarized. Under ideal conditions, the accuracy of the methods used is about 3 percent. This level of accuracy is not sustained over the entire study area. When pumpage for the entire area is mapped, the estimates seem to be consistent areally and through time. A multiple linear-regression model was used to synthesize data for the years 1961 through 1977, when power data were not available. The model used a relation between ground-water pumpage and climatic indexes to develop a full suite of pumpage data to be used as input to a digital ground-water model, one of the products of the Central Valley Aquifer Project. Statistical analysis of well-perforation data from drillers ' logs and water-temperature data was used to determine the percentage of pumpage that was withdrawn from each of two horizontal layers. (USGS)

  16. Reanalysis of S-to-P amplitude ratios for gross attenuation structure, Long Valley caldera, California

    SciTech Connect

    Sanders, C.O.

    1993-12-01

    Because of the strong interest in the magmatism and volcanism at Long Valley caldera, eastern California, and because of recent sifnigicant improvements in our knowledge of the caldera velocity structure and earthquake locations, I have reanalyzed the local-earthquake S-to-P amplitude-ratio data of Sanders (1984) for the gross three-dimensional attenuation structure of the upper 10 km of Long Valley caldera. The primary goals of the analysis are to provide more accurate constraints on the depths of the attenuation anomalies using improved knowledge of the ray locations and an objective inversion procedure. The new image of the high S wave attenuation anomaly in the west-central cadlera suggests that the top of the principal anomaly is at 7-km depth, which is 2 km deeper than previously determined. Because of poor resolution in much of the region, some of the data remain unsatisfied by the final attenuation model. This unmodeled data may imply unresolved attenuation anomalies, perhaps small anomalies in the kilometer or two just above the central-caldera anomaly and perhaps a larger anomaly at about 7-km depth in the northwest caldera or somewhere beneath the Mono Craters. The central-caldera S wave attenuation anomaly has a location similar to mapped regions of low teleseismic P wave velocity, crustal inflation, reduced density, and aseismicity, strongly suggesting magmatic association.

  17. Ground-water resources of Honey Lake valley, Lassen County, California, and Washoe County, Nevada

    USGS Publications Warehouse

    Handman, E.H.; Londquist, C.J.; Maurer, D.K.

    1990-01-01

    Honey Lake Valley is a 2,200 sq-mi, topographically closed basin about 35 miles northwest of Reno, Nevada. Unconsolidated basin-fill deposits on the valley floor and fractured volcanic rocks in northern and eastern uplands are the principal aquifers. In the study area, about 130,000 acre- ft of water recharges the aquifer system annually, about 40% by direct infiltration of precipitation and about 60% by infiltration of streamflow and irrigation water. Balancing this is an equal amount of groundwater discharge, of which about 65% evaporates from the water table or is transpired by phreatophytes, about 30 % is withdrawn from wells, and about 5% leaves the basin as subsurface outflow to the east. Results of a groundwater flow model of the eastern part of the basin, where withdrawals for public supply have been proposed, indicate that if 15,000 acre-ft of water were withdrawn annually, a new equilibrium would eventually be established by a reduction of about 60% in both evapotranspiration and subsurface outflow to the east. Hydrologic effects would be minimal at the western boundary of the flow-model area. Within the modeled area, the increased withdrawals cause an increase in the simulated net flow of groundwater eastward across the California-Nevada State line from about 670 acre-ft/yr to about 2,300 acre-ft/yr. (USGS)

  18. A plan to study the aquifer system of the Central Valley of California

    USGS Publications Warehouse

    Bertoldi, Gilbert L.

    1979-01-01

    Unconsolidated Quaternary alluvial deposits comprise a large complex aquifer system in the Central Valley of California. Millions of acre-feet of water is pumped from the system annually to support a large and expanding agribusiness industry. Since the 1950's, water levels have been steadily declining in many areas of the valley and concern has been expressed about the ability of the entire ground-water system to support agribusiness at current levels, not to mention its ability to function at projected expansion levels. At current levels of ground-water use, an estimated 1.5 to 2 million acre-feet is withdrawn from storage each year; that is, 1.5 to 2 million acre-feet of water is pumped annually in excess of annual replenishment. The U.S. Geological Survey has initiated a 4-year study to develop geologic, hydrologic, and hydraulic information and to establish a valleywide ground-water data base that will be used to build computer models of the ground-water flow system. Subsequently, these models may be used to evaluate the system response to various ground-water management alternatives. This report describes current problems, objectives of the study, and outlines the general work to be accomplished in the study area. A bibliography of about 600 references is included. (Kosco-USGS)

  19. Effects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations

    USGS Publications Warehouse

    Brown, Larry R.; Bauer, Marissa L.

    2010-01-01

    Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools. In this paper, we evaluate how existing hydrologic infrastructure and management affect streamflow characteristics of rivers in the Central Valley, California and discuss those characteristics in the context of habitat requirements of native and alien fishes. We evaluated the effects of water management by comparing observed discharges with estimated discharges assuming no water management ("full natural runoff"). Rivers in the Sacramento River drainage were characterized by reduced winter–spring discharges and augmented discharges in other months. Rivers in the San Joaquin River drainage were characterized by reduced discharges in all months but particularly in winter and spring. Two largely unaltered streams had hydrographs similar to those based on full natural runoff of the regulated rivers. The reduced discharges in the San Joaquin River drainage streams are favourable for spawning of many alien species, which is consistent with observed patterns of fish distribution and abundance in the Central Valley. However, other factors, such as water temperature, are also important to the relative success of native and alien resident fishes. As water management changes in response to climate change and societal demands, interdisciplinary programs of research and monitoring will be essential for anticipating effects on fishes and to avoid unanticipated ecological outcomes.

  20. Isostatic gravity map of the Death Valley ground-water model area, Nevada and California

    SciTech Connect

    Ponce, D.A.; Blakely, R.J.; Morin, R.L.; Mankinen, E.A.

    2002-03-12

    Gravity investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwestern Nevada and parts of California. The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W. An isostatic gravity map of the Death Valley ground-water model was prepared from over 40,000 gravity stations, most of which are publicly available on a CD-ROM of gravity data of Nevada (Ponce, 1997). The map also includes gravity data recently collected by the U.S. Geological Survey (Mankinen and others, 1998; Morin and Blakely, 1999). A subset of these gravity data in the Nevada Test Site and vicinity were described in detail by Harris and others (1989) who included information on gravity meters used, dates of collection, sources, descriptions of base stations, plots of data, and digital and paper lists of principal facts. For display purposes only, gravity data within Yucca Flat were thinned by a factor of 10. The digital gravity data set was gridded at an interval of 400 m using a computer program (Webring, 1981) based on a minimum curvature algorithm by Briggs (1974). The resulting grid was then interpolated to a 200-m grid to minimize pixel size, and then it was color contoured.

  1. Imaging the magmatic and hydrothermal systems of Long Valley Caldera, California with magnetotellurics

    NASA Astrophysics Data System (ADS)

    Peacock, J.; Mangan, M.; McPhee, D.; Ponce, D. A.

    2015-12-01

    Long Valley Caldera (LVC) in Eastern California contains active hydrothermal systems, areas of episodic seismicity, and areas of elevated gas emissions, all of which are related to a deeper magmatic system that is not well characterized. To better image the Long Valley magmatic system, 60 full-tensor broadband magnetotelluric (MT) stations were collected in LVC and modeled in three-dimensions to constrain the subsurface electrical resistivity structure down to 30 km. Three conductive zones are imaged in the preferred resistivity model. The most prominent conductive zone (<7 Ohm-m) is located 5 km beneath the resurgent dome (near the center of Long Valley Caldera), where it elongates in a north-south direction, and has westward connection to the surface close to well 44-16 near Deer Mountan. This conductive zone is interpreted to be an accumulation zone of hydrothermal fluids originating from a deeper magmatic source. The shape of the conductive body suggests that the fluids pool under the resurgent dome and migrate westward, upwelling just south of well 44-16 to feed the near surface geothermal system. A second conductive zone (<10 Ohm-m) is 4 km southeast of the resurgent dome and 5 km deep and coincident with the seismic swarm of 2014. This is another zone of fluid accumulation, where the source could be the fluid accumulation zone to the west or an independent deeper source. The third conductive anomaly (<10 Ohm-m) is a few kilometers south of the resurgent dome below a depth of 15 km, and collocated with a low p- and s-wave velocity zone, and directly beneath a GPS inflation area, all of which advocate for a magma mush zone of as much as 30% interstitial melt. The preferred resistivity model suggests an accumulation of hydrothermal fluids 5 km below the resurgent dome that originates from a deeper magmatic source at 15 km depth.

  2. Valley aggradation in the San Gabriel Mountains, California: climate change versus catastrophic landslide

    NASA Astrophysics Data System (ADS)

    Scherler, D.; Lamb, M. P.; Rhodes, E. J.; Avouac, J. P.

    2014-12-01

    The San Gabriel Mountains (SGM) in Southern California, rate amongst the most rapidly uplifting and eroding mountains in the United States. Their steep slopes and sensitivity to wildfires, flash floods, landslides, and debris flows account for imminent hazards to nearby urban areas that might be accentuated by climatic and other environmental changes. Previous studies suggested that river terraces along the North Fork of the San Gabriel River, record temporal variations in sediment supply and river transport capacity that are representative for the SGM and related to climatic changes during the Quaternary. Based on field observations, digital topographic analysis, and dating of Quaternary deposits, we suggest that valley aggradation in the North Fork San Gabriel Canyon was spatially confined and a consequence of the sudden supply of unconsolidated material to upstream reaches by one of the largest known landslides in the SGM. New 10Be-derived surface exposure ages from the landslide deposits, previously assumed to be early to middle Pleistocene in age, indicate at least three Holocene events at ~8-9 ka, ~4-5 ka, and ~0.5-1 ka. The oldest landslide predates the valley aggradation period, which is constrained by existing 14C ages and new luminescence ages to ~7-8 ka. The spatial distribution, morphology, and sedimentology of the river terraces are consistent with deposition from far-travelling debris flows that originated within the landslide deposits. Valley aggradation in the North Fork San Gabriel Canyon therefore resulted from locally enhanced sediment supply that temporarily overwhelmed river capacity but the lack of similar deposits in other parts of the SGM argues against a regional climatic signal. So far, there exists no evidence that in the San Gabriel Mountains, climatic changes can cause sustained increases in hillslope sediment supply that lead to river aggradation and terrace formation.

  3. Mapping playa evaporite minerals and associated sediments in Death Valley, California, with multispectral thermal infrared images

    USGS Publications Warehouse

    Crowley, J.K.; Hook, S.J.

    1996-01-01

    Efflorescent salt crusts and associated sediments in Death Valley, California, were studied with remote-sensing data acquired by the NASA thermal infrared multispectral scanner (TIMS). Nine spectral classes that represent a variety of surface materials were distinguished, including several classes that reflect important aspects of the playa groundwater chemistry and hydrology. Evaporite crusts containing abundant thenardite (sodium sulfate) were mapped along the northern and eastern margins of the Cottonball Basin, areas where the inflow waters are rich in sodium. Gypsum (calcium sulfate) crusts were more common in the Badwater Basin, particularly near springs associated with calcic groundwaters along the western basin margin. Evaporite-rich crusts generally marked areas where groundwater is periodically near the surface and thus able to replenish the crusts though capillary evaporation. Detrital silicate minerals were prevalent in other parts of the salt pan where shallow groundwater does not affect the surface composition. The surface features in Death Valley change in response to climatic variations on several different timescales. For example, salt crusts on low-lying mudflats form and redissolve during seasonal-to-interannual cycles of wetting and desiccation. In contrast, recent flooding and erosion of rough-salt surfaces in Death Valley probably reflect increased regional precipitation spanning several decades. Remote-sensing observations of playas can provide a means for monitoring changes in evaporite facies and for better understanding the associated climatic processes. At present, such studies are limited by the availability of suitable airborne scanner data. However, with the launch of the Earth Observing System (EOS) AM-1 Platform in 1998, multispectral visible/near-infrared and thermal infrared remote-sensing data will become globally available. Copyright 1996 by the American Geophysical Union.

  4. Climate Change Impacts on Water Resources and Irrigated Agriculture in the Central Valley of California

    NASA Astrophysics Data System (ADS)

    Winter, J.; Young, C. A.; Azarderakhsh, M.; Ruane, A. C.; Rosenzweig, C.

    2013-12-01

    Agricultural productivity is strongly dependent on the availability of water, necessitating accurate projections of water resources, the allocation of water resources across competing sectors, and the effects of insufficient water resources on crops to assess the impacts of climate change on agricultural productivity. To explore the interface of water and agriculture in California's Central Valley, the Decision Support System for Agrotechnology Transfer (DSSAT) crop model was coupled to the Water Evaluation and Planning System (WEAP) water resources model, deployed over the region, and run using both historical and future climate scenarios. This coupling brings water supply constraints to DSSAT and sophisticated agricultural water use, management, and diagnostics to WEAP. A 30-year simulation of WEAP-DSSAT forced using a spatially interpolated observational dataset was run from 1980-2009. Moderate Resolution Imaging Spectroradiometer Surface Resistance and Evapotranspiration (MOD16) and Terrestrial Observation and Prediction System (TOPS) data were used to evaluate WEAP-DSSAT evapotranspiration calculations. Overall WEAP-DSSAT reasonably captures the seasonal cycle of observed evapotranspiration, but some catchments contain significant biases. Future climate scenarios were constructed by adjusting the spatially interpolated observational dataset with North American Regional Climate Change Assessment Program differences between future (2050-2069) and historical (1980-1999) regional climate model simulations of precipitation and temperature. Generally, within the Central Valley temperatures warm by approximately 2°C, precipitation remains constant, and crop water use efficiency increases. The overall impacts of future climate on irrigated agricultural yields varies across the Central Valley and is highly dependent on crop, water resources demand assumptions, and agricultural management.

  5. Microbial and Dissolved Organic Carbon Characterization of Stormflow in the Santa Ana River at Imperial Highway, Southern California, 1999-2002

    USGS Publications Warehouse

    Izbicki, John A.; Pimentel, M. Isabel; Leddy, Menu; Bergamaschi, Brian A.

    2004-01-01

    The Santa Ana River drains about 2,670 square miles of densely populated coastal southern California, near Los Angeles. Almost all the flow in the river, more than 200,000 acre-feet annually, is diverted to ponds where it infiltrates and recharges underlying aquifers pumped to supply water for more than 2 million people. Base flow in the river is almost entirely treated municipal wastewater discharged from upstream treatment plants and, in the past, stormflow was considered a source of high-quality water suitable for use as a source of ground-water recharge that would dilute poorer quality water recharged during base flow. Stormflow in the Santa Ana River at the Imperial Highway diversion contains total coliform bacteria concentrations as high as 3,400,000 colonies per 100 mL (milliliters). Fecal indicator bacteria concentrations, including fecal coliforms, Escherichia coli, and enterococci, were as high as 310,000, 84,000, and 102,000 colonies per 100 mL, respectively. Although concentrations were high owing to urban runoff during the first stormflow of the rainy season, the highest concentrations occurred during the recessional flows of the first stormflow of the rainy season after streamflow returned to pre-storm conditions. Molecular indicators of microbiological organisms in stormflow, including phospholipid fatty acid (PLFA) and genetic data, show that the diversity of the total microbial population decreases during stormflow while fecal indicator bacteria concentrations increase. This suggests that the source of the bacteria must be poorly diverse and dominated by only a few types of bacteria. Although direct runoff of fecal indicator bacteria from urban areas occurs, this process cannot explain the very high concentrations of fecal indicator bacteria in runoff from upstream parts of the basin characterized by urban, agricultural (including more than 300,000 head of dairy cattle), and other land uses. Although other explanations are possible, fecal indicator

  6. Potential hazards from floodflows in Grapevine Canyon, Death Valley National Monument, California and Nevada

    USGS Publications Warehouse

    Bowers, J.C.

    1990-01-01

    Grapevine Canyon is on the western slope of the Grapevine Mountains in the northern part of Death Valley National Monument , California and Nevada. Grapevine Canyon Road covers the entire width of the canyon floor in places and is a frequently traveled route to Scotty 's Castle in the canyon. The region is arid and subject to flash flooding because of infrequent but intense convective storms. When these storms occur, normally in the summer, the resulting floods may create a hazard to visitor safety and property. Historical data on rainfall and floodflow in Grapevine Canyon are sparse. Data from studies made for similar areas in the desert mountains of southern California provide the basis for estimating discharges and the corresponding frequency of floods in the study area. Results of this study indicate that high-velocity flows of water and debris , even at shallow depths, may scour and damage Grapevine Canyon Road. When discharge exceeds 4,900 cu ft/sec, expected at a recurrence interval of between 25 and 50 years, the Scotty 's Castle access road and bridge may be damaged and the parking lot partly inundated. A flood having a 100-year or greater recurrence interval probably would wash out the bridge and present a hazard to the stable and garage buildings but not to the castle buildings, whose foundations are higher than the predicted maximum flood level. (USGS)

  7. Transport and dispersion during wintertime particulate matter episodes in the San Joaquin Valley, California.

    PubMed

    MacDonald, Clinton P; McCarthy, Michael C; Dye, Timothy S; Wheeler, Neil J M; Hafner, Hilary R; Roberts, Paul T

    2006-07-01

    Data analysis and modeling were performed to characterize the spatial and temporal variability of wintertime transport and dispersion processes and the impact of these processes on particulate matter (PM) concentrations in the California San Joaquin Valley (SJV). Radar wind profiler (RWP) and radio acoustic sounding system (RASS) data collected from 18 sites throughout Central California were used to estimate hourly mixing heights for a 3-month period and to create case studies of high-resolution diagnostic wind fields, which were used for trajectory and dispersion analyses. Data analyses show that PM episodes were characterized by an upper-level ridge of high pressure that generally produced light winds through the entire depth of the atmospheric boundary layer and low mixing heights compared with nonepisode days. Peak daytime mixing heights during episodes were -400 m above ground level (agl) compared with -800 m agl during nonepisodes. These episode/nonepisode differences were observed throughout the SJV. Dispersion modeling indicates that the range of influence of primary PM emitted in major population centers within the SJV ranged from -15 to 50 km. Trajectory analyses revealed that little intrabasin pollutant transport occurred among major population centers in the SJV; however, interbasin transport from the northern SJV and Sacramento regions into the San Francisco Bay Area (SFBA) was often observed. In addition, this analysis demonstrates the usefulness of integrating RWP/RASS measurements into data analyses and modeling to improve the understanding of meteorological processes that impact pollution, such as aloft transport and boundary layer evolution. PMID:16878588

  8. Simi Valley, California, Perspective View of Shaded Relief, color as height

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This topographic perspective view shows an area of Ventura County, California, including Simi Valley in the center of the image. The view is toward the East. At the lower left is the Santa Clara River Valley. The mountains along the left of the image are Oak Ridge, known to be an active zone of seismic uplift. San Fernando Valley is smooth area at top. Hazards from earthquakes, floods and fires are intimately related to the topography in this area. Topographic data and other remote sensing images provide valuable information for assessing and mitigating the natural hazards in regions such as Southern California.

    This shaded relief perspective view was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to red at the highest elevations. This image contains about 750 meters (2500 feet) of total relief. To emphasize subtle differences in topography, the relief is exaggerated by a factor of 5.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and

  9. Shallow-Depth Velocities and Structure Within the San Bernardino Valley, California

    NASA Astrophysics Data System (ADS)

    Goldman, M. R.; Catchings, R. R.; Rymer, M. J.; Heverin, C.; Woolfenden, L. R.

    2001-12-01

    A series of high-resolution seismic reflection and refraction profiles were acquired in the San Bernardino Valley, Southern California, in May of 1999 as part of an ongoing investigation by the U.S. Geological Survey to determine seismic hazards and to evaluate groundwater resources in southern California. We present data from three seismic profiles within the cities of Colton, Rialto, and Fontana. The seismic profiles ranged in length from 1 to 2 km and trended north-south along city streets. The objectives of the seismic imaging investigation were to image the shallow (upper 500 m) subsurface along a northwest-trending gravity anomaly believed to result from offset along the buried extension of the Rialto-Colton fault, to determine depth to basement rocks, and to measure P-wave velocities in the basin. Along each profile seismic energy was generated from 400 grain, 8-gauge shotgun blasts in 0.3-m-deep holes and recorded by ~235 channels. Geophones and shot points were spaced at 5-m increments. Four seconds of data were recorded for each shot at a sampling rate of 0.5 ms. The signal-to-noise ratio was relatively low within the highly urbanized areas, but first-arrival refractions are traceable for distances to several hundred meters, and clear reflections are apparent on most shot gathers. As both refractions and reflections are available from the same data, we produced both tomographic velocity models (upper 50 m) and stacked reflection images (upper 500 m) of the subsurface. Velocities range from about 400 m/s in the near surface to about 1500 m/s at ~35 m depth. These data show lateral disruptions in sediments with velocities of ~1500 m/s, which probably represent the ground-water table. Stacked seismic images suggest the presence of multiple faults along each of the profiles, some of which correlate with the disruptions in the 1500 m/s velocity contour. Multiple faults imaged along the profiles suggests that faulting along the Rialto-Colton fault is

  10. Map of the Rinconada and Reliz Fault Zones, Salinas River Valley, California

    USGS Publications Warehouse

    Rosenberg, Lewis I.; Clark, Joseph C.

    2009-01-01

    The Rinconada Fault and its related faults constitute a major structural element of the Salinas River valley, which is known regionally, and referred to herein, as the 'Salinas Valley'. The Rinconada Fault extends 230 km from King City in the north to the Big Pine Fault in the south. At the south end of the map area near Santa Margarita, the Rinconada Fault separates granitic and metamorphic crystalline rocks of the Salinian Block to the northeast from the subduction-zone assemblage of the Franciscan Complex to the southwest. Northwestward, the Rinconada Fault lies entirely within the Salinian Block and generally divides this region into two physiographically and structurally distinct areas, the Santa Lucia Range to the west and the Salinas Valley to the east. The Reliz Fault, which continues as a right stepover from the Rinconada Fault, trends northwestward along the northeastern base of the Sierra de Salinas of the Santa Lucia Range and beyond for 60 km to the vicinity of Spreckels, where it is largely concealed. Aeromagnetic data suggest that the Reliz Fault continues northwestward another 25 km into Monterey Bay, where it aligns with a high-definition magnetic boundary. Geomorphic evidence of late Quaternary movement along the Rinconada and Reliz Fault Zones has been documented by Tinsley (1975), Dibblee (1976, 1979), Hart (1976, 1985), and Klaus (1999). Although definitive geologic evidence of Holocene surface rupture has not been found on these faults, they were regarded as an earthquake source for the California Geological Survey [formerly, California Division of Mines and Geology]/U.S. Geological Survey (CGS/USGS) Probabilistic Seismic Hazards Assessment because of their postulated slip rate of 1+-1 mm/yr and their calculated maximum magnitude of 7.3. Except for published reports by Durham (1965, 1974), Dibblee (1976), and Hart (1976), most information on these faults is unpublished or is contained in theses, field trip guides, and other types of reports

  11. Social Disparities in Drinking Water Quality in California's San Joaquin Valley

    NASA Astrophysics Data System (ADS)

    Ray, I.; Balazs, C.; Hubbard, A.; Morello-Frosch, R.

    2011-12-01

    Social Disparities in Drinking Water Quality in California's San Joaquin Valley Carolina Balazs, Rachel Morello-Frosch, Alan Hubbard and Isha Ray Little attention has been given to research on social disparities and environmental justice in access to safe drinking water in the USA. We examine the relationship between nitrate and arsenic concentrations in community water systems (CWS) and the ethnic and socioeconomic characteristics of their customers. We hypothesized that systems in the San Joaquin Valley that serve a higher proportion of minority (especially Latino) residents, and/or lower socioeconomic status (proxied by rates of home ownership) residents, have higher nitrate levels and higher arsenic levels. We used water quality monitoring datasets (1999-2001) to estimate nitrate as well as arsenic levels in CWS, and source location and Census block group data to estimate customer demographics. We found that percent Latino was associated with a .04 mg NO3/L increase in a CWS' estimated nitrate ion concentration (95% CI, -.08, .16) and rate of home ownership was associated with a .16 mg NO3/L decrease (95% CI, -.32, .002). We also found that each percent increase in home ownership rate was associated with a .30 ug As/L decrease in arsenic concentrations (p<.05), but our data showed no significant correlation between arsenic concentration and percent Latino. These results show that exposure disparities and compliance burdens in accordance with EPA standards fell most heavily on socio-economically disadvantaged communities. Selected References Cory DC, Rahman T. 2009. Environmental justice and enforcement of the safe drinking water act: The arizona arsenic experience. Ecological Economics 68: 1825-1837. Krieger N, Williams DR, Moss NE. 1997. Measuring social class in us public health research: Concepts, methodologies, and guidelines. Annual Review of Public Health 18(341-378). Moore E, Matalon E, Balazs C, Clary J, Firestone L, De Anda S, Guzman, M. 2011. The

  12. Keeping the History in Historical Seismology: The 1872 Owens Valley, California Earthquake

    SciTech Connect

    Hough, Susan E.

    2008-07-08

    The importance of historical earthquakes is being increasingly recognized. Careful investigations of key pre-instrumental earthquakes can provide critical information and insights for not only seismic hazard assessment but also for earthquake science. In recent years, with the explosive growth in computational sophistication in Earth sciences, researchers have developed increasingly sophisticated methods to analyze macroseismic data quantitatively. These methodological developments can be extremely useful to exploit fully the temporally and spatially rich information source that seismic intensities often represent. For example, the exhaustive and painstaking investigations done by Ambraseys and his colleagues of early Himalayan earthquakes provides information that can be used to map out site response in the Ganges basin. In any investigation of macroseismic data, however, one must stay mindful that intensity values are not data but rather interpretations. The results of any subsequent analysis, regardless of the degree of sophistication of the methodology, will be only as reliable as the interpretations of available accounts - and only as complete as the research done to ferret out, and in many cases translate, these accounts. When intensities are assigned without an appreciation of historical setting and context, seemingly careful subsequent analysis can yield grossly inaccurate results. As a case study, I report here on the results of a recent investigation of the 1872 Owen's Valley, California earthquake. Careful consideration of macroseismic observations reveals that this event was probably larger than the great San Francisco earthquake of 1906, and possibly the largest historical earthquake in California. The results suggest that some large earthquakes in California will generate significantly larger ground motions than San Andreas fault events of comparable magnitude.

  13. Conservation Effects Assessment Project-Wetlands assessment in California's Central Valley and Upper Klamath River Basin

    USGS Publications Warehouse

    2011-01-01

    Executive Summary-Ecosystem Services Derived from Wetlands Reserve Program Conservation Practices in California's Central Valley and Oregon's Upper Klamath River Basin. The Wetlands Reserve Program (WRP) is one of several programs implemented by the U.S. Department of Agriculture (USDA). Since the WRP's inception in 1990, it has resulted in the restoration of approximately 29,000 hectares in California's Central Valley (CCV) and roughly 12,300 hectares in Oregon's Upper Klamath River Basin (UKRB). Both the CCV and UKRB are agricultural dominated landscapes that have experienced extensive wetland losses and hydrological alteration. Restored habitats in the CCV and UKRB are thought to provide a variety of ecosystem services, but little is known about the actual benefits afforded. The U.S. Geological Survey (USGS) California Cooperative Fish and Wildlife Unit in collaboration with the USDA Natural Resources Conservation Service surveyed 70 WRP sites and 12 National Wildlife Refuge sites in the CCV, and 11 sites in the UKRB to estimate ecosystem services provided. In the CCV, sites were selected along three primary gradients; (1) restoration age, (2) management intensity, and (3) latitude (climate). Sites in the UKRB were assessed along restoration age and management intensity gradients where possible. The management intensity gradient included information about the type and frequency of conservation practices applied at each site, which was then ranked into three categories that differentiated sites primarily along a hydrological gradient. Information collected was used to estimate the following ecosystem services: Soil and vegetation nutrient content, soil loss reduction, floodwater storage as well as avian, amphibian, fish, and pollinator use and habitat availability. Prior to this study, very little was known about WRP habitat morphology in the CCV and UKRB. Therefore in this study, we described these habitats and related them to ecosystem services provided. Our

  14. Field Scale Groundwater Nitrate Loading Model for the Central Valley, California, 1945-Current

    NASA Astrophysics Data System (ADS)

    Harter, T.; Dzurella, K.; Bell, A.; Kourakos, G.

    2015-12-01

    Anthropogenic groundwater nitrate contamination in the Central Valley aquifer system, California, is widespread, with over 40% of domestic wells in some counties exceeding drinking water standards. Sources of groundwater nitrate include leaky municipal wastewater systems, municipal wastewater recharge, onsite wastewater treatment (septic) systems, atmospheric nitrogen deposition, animal farming, application of organic waste materials (sludge, biosolids, animal manure) to agricultural lands, and synthetic fertilizer. At the site or field scale, nitrogen inputs to the landscape are balanced by plant nitrogen uptake and harvest, atmospheric nitrogen losses, surface runoff of nitrogen, soil nitrogen storage changes, and leaching to groundwater. Irrigated agriculture is a dominant player in the Central Valley nitrogen cycle: The largest nitrogen fluxes are synthetic fertilizer and animal manure applications to cropland, crop nitrogen uptake, and groundwater nitrogen losses. We construct a historic field/parcel scale groundwater nitrogen loading model distinguishing urban and residential areas, individual animal farming areas, leaky wastewater lagoons, and approximately 50 different categories of agricultural crops. For non-agricultural landuses, groundwater nitrate loading is based on reported leaching values, animal population, and human population. For cropland, groundwater nitrate loading is computed from mass balance, taking into account diverse and historically changing management practices between different crops. Groundwater nitrate loading is estimated for 1945 to current. Significant increases in groundwater nitrate loading are associated with the expansion of synthetic fertilizer use in the 1950s to 1970s. Nitrate loading from synthetic fertilizer use has stagnated over the past 20 years due to improvements in nutrient use efficiency. However, an unbroken 60 year exponential increase in dairy production until the late 2000s has significantly impacted the

  15. Results of a shallow seismic-refraction survey in the Little Valley area near Hemet, Riverside County, California

    USGS Publications Warehouse

    Duell, L.F., Jr.

    1995-01-01

    Little Valley, a small locally named valley southeast of the city of Hemet in Riverside County, California, is being evaluated for development of a constructed wetland and infiltration area as part of a water-resources management program in the area. The valley is a granitic basin filled with unconsolidated material. In August 1993 and June and July 1994, the U.S. Geological Survey conducted a seismic-refraction survey consisting of four lines northwest of the valley, eight lines in the valley, and six lines northeast of the valley. Two interpretations were made for the lines: a two-layer model yielded an estimate of the minimum depths to bedrock and a three-layer model yielded the most likely depths to bedrock. Results of the interpretation of the three-layer model indicate that the unsaturated unconsolidated surface layer ranges in thickness from 12 to 83 feet in the valley and 24 to 131 feet northeast of the valley. The mean compressional velocity for this layer was about 1,660 feet per second. A saturated middle layer was detected in some parts of the study area, but not in others--probably because of insufficient thickness in some places; however, in order to determine the "most likely" depths to bedrock, it was assumed that the layer was present throughout the valley. Depths to this layer were verified on three seismic lines using the water level from the only well in the valley. Data for additional verification were not available for wells near Little Valley. The bedrock slope from most of Little Valley is down toward the northeast. Bedrock profiles show that the bedrock surface is very uneven in the study area. The interpreted most likely depth to bedrock in the valley ranged from land surface (exposed) to a depth of 176 feet below land surface, and northeast of the valley it ranged from 118 to 331 feet below land surface. Bedrock depths were verified using lithologic logs from test holes drilled previously in the area. On the basis of a measured mean

  16. CRUSTAL REFRACTION PROFILE OF THE LONG VALLEY CALDERA, CALIFORNIA, FROM THE JANUARY 1983 MAMMOTH LAKES EARTHQUAKE SWARM.

    USGS Publications Warehouse

    Luetgert, James H.; Mooney, Walter D.

    1985-01-01

    Seismic-refraction profiles recorded north of Mammoth Lakes, California, using earthquake sources from the January 1983 swarm complement earlier explosion refraction profiles and provide velocity information from deeper in the crust in the area of the Long Valley caldera. Eight earthquakes from a depth range of 4. 9 to 8. 0 km confirm the observation of basement rocks with seismic velocities ranging from 5. 8 to 6. 4 km/sec extending at least to depths of 20 km. The data provide further evidence for the existence of a partial melt zone beneath Long Valley caldera and constrain its geometry. Refs.

  17. Geohydrology and water-chemistry of the Alexander Valley, Sonoma County, California

    USGS Publications Warehouse

    Metzger, Loren F.; Farrar, Christopher D.; Koczot, Kathryn M.; Reichard, Eric G.

    2006-01-01

    This study of the geohydrology and water chemistry of the Alexander Valley, California, was done to provide an improved scientific basis for addressing emerging water-management issues, including potential increases in water demand and changes in flows in the Russian River. The study tasks included (1) evaluation of existing geohydrological, geophysical, and geochemical data; (2) collection and analysis of new geohydrologic data, including subsurface lithologic data, ground-water levels, and streamflow records; and (3) collection and analysis of new water-chemistry data. The estimated total water use for the Alexander Valley for 1999 was approximately 15,800 acre-feet. About 13,500 acre-feet of this amount was for agricultural use, primarily vineyards, and about 2,300 acre-feet was for municipal/industrial use. Ground water is the main source of water supply for this area. The main sources of ground water in the Alexander Valley are the Quaternary alluvial deposits, the Glen Ellen Formation, and the Sonoma Volcanics. The alluvial units, where sufficiently thick and saturated, comprise the best aquifer in the study area. Average recharge to the Alexander Valley is estimated from a simple, basinwide water budget. On the basis of an estimated annual average of 298,000 acre-feet of precipitation, 160,000 acre-feet of runoff, and 113,000 to 133,000 acre-feet of evapotranspiration, about 5,000 to 25,000 acre-feet per year is available for ground-water recharge. Because this estimate is based on differences between large numbers, there is significant uncertainty in this recharge estimate. Long-term changes in ground-water levels are evident in parts of the study area, but because of the sparse network and lack of data on well construction and lithology, it is uncertain if any significant changes have occurred in the northern part of the study area since 1980. In the southern half of the study area, ground-water levels generally were lower at the end of the 2002 irrigation

  18. Antelope Valley-East Kern Water Agency area, California, showing ground-water subunits and areas, location of wells, and lines of equal depth to water

    USGS Publications Warehouse

    Blankenbaker, G.G.

    1978-01-01

    The U.S. Geological Survey has released to the open file a map showing ground-water subunits and areas, and depth to water for spring 1978, in the Antelope Valley-East Kern Water Agency area, California.

  19. 75 FR 45653 - Notice of Re-Opening of Comment Period for the Draft Imperial Sand Dunes Recreation Area...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ... Bureau of Land Management Notice of Re-Opening of Comment Period for the Draft Imperial Sand Dunes... of the comment period on the Draft Imperial Sand Dunes Recreation Area Management Plan (RAMP) and... So. 4th St., El Centro, California 92243. Copies of the Draft Imperial Sand Dunes RAMP/EIS...

  20. Groundwater Age in Multi-Level Water Quality Monitor Wells on California Central Valley Dairies

    NASA Astrophysics Data System (ADS)

    Esser, B. K.; Visser, A.; Hillegonds, D. J.; Singleton, M. J.; Moran, J. E.; Harter, T.

    2011-12-01

    Dairy farming in California's Central Valley is a significant source of nitrate to underlying aquifers. One approach to mitigation is to implement farm-scale management plans that reduce nutrient loading to groundwater while sustaining crop yield. While the effect of different management practices on crop yield is easily measured, their effect on groundwater quality has only infrequently been evaluated. Documenting and predicting the impact of management on water quality requires a quantitative assessment of transport (including timescale and mixing) through the vadose and saturated zones. In this study, we measured tritium, helium isotopic composition, and noble gas concentrations in groundwater drawn from monitor wells on several dairies in the Lower San Joaquin Valley and Tulare Lake Basin of California's Central Valley in order to predict the timescales on which changes in management may produce observable changes in groundwater quality. These dairies differ in age (from <10 to >100 years old), thickness of the vadose zone (from <10 to 60 m), hydrogeologic setting, and primary source of irrigation water (surface or groundwater). All of the dairies use manure wastewater for irrigation and fertilization. Three of the dairies have implemented management changes designed to reduce nutrient loading and/or water usage. Monitor wells in the southern Tulare Lake Basin dairies were installed by UC-Davis as multi-level nested wells allowing depth profiling of tritium and noble gases at these sites. Tritium/helium-3 groundwater ages, calculated using a simple piston-flow model, range from <2 to >50 years. Initial tritium (the sum of measured tritium and tritiogenic helium-3) is close to or slightly above precipitation in the calculated recharge year for young samples; and significantly above the precipitation curve for older samples. This pattern is consistent with the use of 20-30 year old groundwater recharged before 1980 for irrigation, and illustrates how irrigation

  1. Tectonic map of the Death Valley ground-water model area, Nevada and California

    SciTech Connect

    J.B. Workman; C.M. Menges; W.R. Page; E.B. Ekren; P.D. Rowley; G.L. Dixon

    2002-10-17

    The purpose of this map is to provide tectonic interpretations in the Death Valley ground-water model area to be incorporated into a transient ground-water flow model by the U.S. Geological Survey (D'Agnese, 2000; D'Agnese and Faunt, 1999; Faunt and others, 1999; and O'Brien and others, 1999). This work has been conducted in collaboration with the U.S. Department of Energy in order to assess regional ground-water flow near the Nevada Test Site (NTS) and the potential radioactive waste repository at Yucca Mountain. The map is centered on the NTS and its perimeter encircles the entire boundary of the numerical flow model area, covering a total area of 57,000 square kilometers. This tectonic map is a derivative map of the geologic map of the Death Valley ground-water model, Nevada and California (Workman and others, 2002). Structures portrayed on the tectonic map were selected from the geologic map based upon several criteria including amount of offset on faults, regional significance of structures, fault juxtaposition of rocks with significantly different hydrologic properties, and the hydrologic properties of the structures themselves. Inferred buried structures in the basins were included on the map (blue and light blue dotted lines) based on interpretation of geophysical data (Ponce and others, 2001; Ponce and Blakely, 2001; Blakely and Ponce, 2001). In addition, various regional trends of fault zones have been delineated which are composed of multiple smaller scale features. In some cases, these structures are deeply buried and their location is based primarily on geophysical evidence. In all cases, these zones (shown as broad red and blue stippled bands on the map) are significant structures in the region. Finally, surface exposures of Precambrian crystalline rocks and igneous intrusions of various ages are highlighted (red and blue patterns) on the map; these rocks generally act as barriers to groundwater flow unless significantly fractured.

  2. Petrology of a Jurassic cold seep carbonate mound, Great Valley Group, northern California

    SciTech Connect

    Campbell, K.A.; Bottjer, D.J. . Dept. of Geological Sciences)

    1992-01-01

    Ancient sites of chemosynthetic marine invertebrate communities have been increasingly described from the stratigraphic record. Fossil cold seeps are best identified by the stratigraphically restricted co-occurrence of anomalous carbonates and fossils of organisms that in modern environments are chemosymbiotic. A Late Jurassic (Tithonian) age fossil seep site is preserved in deep-water turbidites of the Stony Creek Formation (Great Valley Group). Two low-relief carbonate mounds contain an abundant and diverse fossil macrofauna including taxa whose modern counterparts are chemosymbiotic, as well as several associate taxa. Two broad carbonate fabric types are present: a bioturbated, peloidal, fossiliferous micrite with abundant flecks of organic matter and several wavy laminated marine cements. The micrite and cements are either irregularly interlayered on distinctly separated by corrosion surfaces coated with iron oxides that may mark pulses of H[sub 2]S-rich fluids to the seep. Petrographic observations indicate the following idealized paragenetic sequence: deposition of micrite, with contemporaneous biotic activity; corrosion event, with preferential preservation of some peloids; precipitation of pyrite on some corrosion surfaces and concentration of insoluble siltstone linings where corrosion has opened vugs; precipitation of blocky yellow calcite cement with organic-rich inclusions in void spaces and around peloids; growth of clear to gray, botryoidal to fibrous cement; and precipitation of late, clear calcite spar. Similar fabrics and abundant tube-like structures are present in another Great Valley carbonate lens of Early Cretaceous (Albian-Aptian) age exposed on the Cold Fork of Cottonwood Creek near Red Bluff, California. Detailed integration of petrological studies of these fabrics with stable isotope studies and fossil faunal distributions provide a powerful approach for understanding the history of development and individual fossil seeps.

  3. Comparison of estimates of evapotranspiration and consumptive use in Palo Verde Valley, California

    USGS Publications Warehouse

    Raymond, Lee H.; Owen-Joyce, Sandra J.

    1987-01-01

    Estimates of evapotranspiration and consumptive use by vegetation in Palo Verde Valley, California, were compared for calendar years 1981 to 1984. Vegetation types were classified, and the areas covered by each type were computed from Landsat satellite digital-image analysis. Evapotranspiration was calculated by multiplying the area of each vegetation type by a corresponding water use rate adjusted for year-to-year variations in climate. The vegetation classification slightly underestimates the total vegetated area when compared to crop reports, because not all multiple cropping could be identified. The accuracy of evapotranspiration calculated from vegetation classification depends primarily on the correct classification of alfalfa and cotton because alfalfa and cotton have larger acreages and use more water/acre than the other crops in the valley. Consumptive use was calculated using a water budget for each of the 4 years. Estimates of evapotranspiration and consumptive use by vegetation, respectively, were: (1) 439,400 and 483,500 acre-ft in 1981, (2) 430,700 and 452,700 acre-ft in 1982, (3) 402,000 and 364,400 acre-ft in 1983, and (4) 406,700 and 373,800 acre-ft in 1984. Evapotranspiration estimates were lower than consumptive use estimates in 1981 and 1982 and higher in 1983 and 1984. Both estimates were lower in 1983 and 1984 than in 1981 and 1982. Yearly differences in estimates correspond most closely to significant changes in stage of the lower Colorado River caused by flood control releases in 1983 and 1984 and to changes in cropping practices. (Author 's abstract)

  4. Calibration of numerical models for small debris flows in Yosemite Valley, California, USA

    USGS Publications Warehouse

    Bertolo, P.; Wieczorek, G.F.

    2005-01-01

    This study compares documented debris flow runout distances with numerical simulations in the Yosemite Valley of California, USA, where about 15% of historical events of slope instability can be classified as debris flows and debris slides (Wieczorek and Snyder, 2004). To model debris flows in the Yosemite Valley, we selected six streams with evidence of historical debris flows; three of the debris flow deposits have single channels, and the other three split their pattern in the fan area into two or more channels. From field observations all of the debris flows involved coarse material, with only very small clay content. We applied the one dimensional DAN (Dynamic ANalysis) model (Hungr, 1995) and the two-dimensional FLO2D model (O'Brien et al., 1993) to predict and compare the runout distance and the velocity of the debris flows observed in the study area. As a first step, we calibrated the parameters for the two softwares through the back analysis of three debris- flows channels using a trial-and-error procedure starting with values suggested in the literature. In the second step we applied the selected values to the other channels, in order to evaluate their predictive capabilities. After parameter calibration using three debris flows we obtained results similar to field observations We also obtained a good agreement between the two models for velocities. Both models are strongly influenced by topography: we used the 30 m cell size DTM available for the study area, that is probably not accurate enough for a highly detailed analysis, but it can be sufficient for a first screening. European Geosciences Union ?? 2005 Author(s). This work is licensed under a Creative Commons License.

  5. Preliminary Hot Dry Rock geothermal evaluation of Long Valley Caldera, California

    SciTech Connect

    Gambill, D.T.

    1981-03-01

    Long Valley Caldera, formed during the catastrophic eruption of the Bishop Tuff 0.7 Myr ago, straddles the border between the Sierra Nevada and the Basin and Range tectonic provinces in eastern California. The caldera contains rhyolitic to basaltic flows, tuffs, and domes from 3.2 Myr to 450 yr old. Sierra Nevada frontal faults intersect the northwest and southeast parts of the caldera. The dominant feature within the caldera is a resurgent dome in the west-central section, which formed between about 0.7 and 0.5 Myr b.p. Teleseismic data indicate a low P-wave velocity zone below the western part of the caldera, indicating a magma chamber between 7 and 25 km depth. This conclusion is supported by gravity data. Heat flow just west of the caldera is 3.75 HFU. Just east of the caldera, measured heat flow is about 2 HFU. However, a deep well on the eastern edge of the resurgent dome has a gradient of 38/sup 0/C/km from 0.66 to 1.2 km suggesting that the magma chamber, which produced Long Valley, is largely crystallized below the resurgent dome. The high heat flow beneath the western caldera may be a manifestation of shallow silicic magma associated with the recent Inyo Craters. These data indicate a smaller magma source may lie below the western caldera. The resurgent dome and the area just west of the caldera are cited for additional Hot Dry Rock prospection. The higher temperature gradient and lack of caldera fill beyond the west margin of the caldera combine to make this area promising for future HDR evaluation.

  6. Inverse modeling of interbed storage parameters using land subsidence observations, Antelope Valley, California

    USGS Publications Warehouse

    Hoffmann, J.; Galloway, D.L.; Zebker, H.A.

    2003-01-01

    We use land-subsidence observations from repeatedly surveyed benchmarks and interferometric synthetic aperture radar (InSAR) in Antelope Valley, California, to estimate spatially varying compaction time constants, ??, and inelastic specific skeletal storage coefficients, Skv*, in a previously calibrated regional groundwater flow and subsidence model. The observed subsidence patterns reflect both the spatial distribution of head declines and the spatially variable inelastic skeletal storage coefficient. Using the nonlinear parameter estimation program UCODE we estimate compaction time constants between 3.8 and 285 years. The Skv* values are estimated by linear estimation and range from 0 to almost 0.09. We find that subsidence observations over long time periods are necessary to constrain estimates of the large compaction time constants in Antelope Valley. The InSAR data used in this study cover only a three-year period, limiting their usefulness in constraining these time constants. This problem will be alleviated as more SAR data become available in the future or where time constants are small. By incorporating the resulting parameter estimates in the previously calibrated regional model of groundwater flow and land subsidence we can significantly improve the agreement between simulated and observed land subsidence both in terms of magnitude and spatial extent. The sum of weighted squared subsidence residuals, a common measure of model fit, was reduced by 73% with respect to the original model. However, the ability of the model to adequately reproduce the subsidence observed over only a few years is impaired by the fact that the simulated hydraulic heads over small time periods are often not representative of the actual aquifer hydraulic heads. Errors in the simulated hydraulic aquifer heads constitute the primary limitation of the approach presented here.

  7. A new hypothesis for the amount and distribution of dextral displacement along the Fish Lake Valley-northern Death Valley-Furnace Creek fault zone, California-Nevada

    NASA Astrophysics Data System (ADS)

    Renik, Byrdie; Christie-Blick, Nicholas

    2013-03-01

    The Fish Lake Valley-northern Death Valley-Furnace Creek fault zone, a ~250 km long, predominantly right-lateral structure in California and Nevada, is a key element in tectonic reconstructions of the Death Valley area, Eastern California Shear Zone and Walker Lane, and central Basin and Range Province. Total displacement on the fault zone is contested, however, with estimates ranging from ~30 to ~63 km or more. Here we present a new synthesis of available constraints. Preextensional thrust faults, folds, and igneous rocks indicate that offset reaches a maximum of ~50 km. Neogene rocks constrain its partitioning over time. Most offset is interpreted as ≤ ~13-10 Ma, accruing at ~3-5 mm/yr in the middle of the fault zone and more slowly toward the tips. The offset markers imply ~68 ± 14 km of translation between the Cottonwood Mountains and Resting Spring-Nopah Range (~60 ± 14 km since ~15 Ma) through a combination of strike slip and crustal extension. This suggests that a previous interpretation of ~104 ± 7 km, based on the middle Miocene Eagle Mountain Formation, is an overestimate by ~50%. Our results also help to mitigate a discrepancy in the ~12-0 Ma strain budget for the Eastern California Shear Zone. Displacement has previously been estimated at ~100 ± 10 km and ~67 ± 6 km for the Basin and Range and Mojave portions of the shear zone, respectively. Our new estimate of ~74 ± 17 km for the Basin and Range is within the uncertainty of the Mojave estimate.

  8. Overwintering biology of Culex (Diptera: Culicidae) mosquitoes in the Sacramento Valley of California.

    PubMed

    Nelms, Brittany M; Macedo, Paula A; Kothera, Linda; Savage, Harry M; Reisen, William K

    2013-07-01

    At temperate latitudes, Culex (Diptera: Culicidae) mosquitoes typically overwinter as adult females in reproductive arrest and also may serve as reservoir hosts for arboviruses when cold temperatures arrest viral replication. To evaluate their role in the persistence of West Nile virus (WNV) in the Sacramento Valley of California, the induction and termination of diapause were investigated for members of the Culex pipiens (L.) complex, Culex tarsalis Coquillett, and Culex stigmatosoma Dyar under field, seminatural, and experimental conditions. All Culex spp. remained vagile throughout winter, enabling the collection of 3,174 females and 1,706 males from diverse habitats during the winters of 2010-2012. Overwintering strategies included both quiescence and diapause. In addition, Cx. pipiens form molestus Forskäl females remained reproductively active in both underground and aboveground habitats. Some blood-fed, gravid, and parous Cx. tarsalis and Cx. pipiens complex females were collected throughout the winter period. Under both field and experimental conditions, Cx. tarsalis and Cx. stigmatosoma females exposed to autumnal conditions arrested primary follicular maturation at previtellogenic stage I, with primary to secondary follicular ratios <1.5 (indicative of a hormonally induced diapause). In contrast, most Cx. pipiens complex females did not enter reproductive diapause and ovarian follicles matured to >or=stage I-II (host-seeking arrest) or were found in various stages of degeneration. Diapause was initiated in the majority of Cx. tarsalis and Cx. stigmatosoma females by mid-late October and was terminated after the winter solstice, but host-seeking seemed limited by temperature. An accrual of 97.52 +/- 30.7 and 162.85 +/- 79.3 degree-days after the winter solstice was estimated to be necessary for diapause termination in Cx. tarsalis under field and seminatural conditions, respectively. An increase in the proportion of blood-fed Culex females in resting

  9. Overwintering Biology of Culex (Diptera: Culicidae) Mosquitoes in the Sacramento Valley of California

    PubMed Central

    NELMS, BRITTANY M.; MACEDO, PAULA A.; KOTHERA, LINDA; SAVAGE, HARRY M.; REISEN, WILLIAM K.

    2014-01-01

    At temperate latitudes, Culex (Diptera: Culicidae) mosquitoes typically overwinter as adult females in reproductive arrest and also may serve as reservoir hosts for arboviruses when cold temperatures arrest viral replication. To evaluate their role in the persistence of West Nile virus (WNV) in the Sacramento Valley of California, the induction and termination of diapause were investigated for members of the Culex pipiens (L.) complex, Culex tarsalis Coquillett, and Culex stigmatosoma Dyar under field, seminatural, and experimental conditions. All Culex spp. remained vagile throughout winter, enabling the collection of 3,174 females and 1,706 males from diverse habitats during the winters of 2010–2012. Overwintering strategies included both quiescence and diapause. In addition, Cx. pipiens form molestus Forskäl females remained reproductively active in both underground and aboveground habitats. Some blood-fed, gravid, and parous Cx. tarsalis and Cx. pipiens complex females were collected throughout the winter period. Under both field and experimental conditions, Cx. tarsalis and Cx. stigmatosoma females exposed to autumnal conditions arrested primary follicular maturation at previtellogenic stage I, with primary to secondary follicular ratios <1.5 (indicative of a hormonally induced diapause). In contrast, most Cx. pipiens complex females did not enter reproductive diapause and ovarian follicles matured to ≥stage I–II (host-seeking arrest) or were found in various stages of degeneration. Diapause was initiated in the majority of Cx. tarsalis and Cx. stigmatosoma females by mid-late October and was terminated after the winter solstice, but host-seeking seemed limited by temperature. An accrual of 97.52 ± 30.7 and 162.85 ± 79.3 degree-days after the winter solstice was estimated to be necessary for diapause termination in Cx. tarsalis under field and seminatural conditions, respectively. An increase in the proportion of blood-fed Culex females in resting

  10. Estimation of Evapotranspiration of Almond orchards using Remote Sensing based SEBAL model in Central Valley, California

    NASA Astrophysics Data System (ADS)

    Roy, S.; Ustin, S.; Kefauver, S. C.

    2009-12-01

    Evapotranspiration is one of the main components of the hydrologic cycle and its impact to hydrology, agriculture,forestry and environmental studies is very crucial. SEBAL (Surface Energy Balance Algorithm for Land) is an image-processing model comprised of twenty-five computational sub-models that computes actual evapotranspiration (ETa) and other energy exchanges as a component of energy balance which is used to derive the surface radiation balance equation for the net surface radiation flux (Rn) on a pixel-by-pixel basis. For this study, SEBAL method is applied to Level 1B dataset of visible, near-infrared and thermal infrared radiation channels of MASTER instrument on-board NASA-DC 8 flight. This paper uses the SEBAL method to (1) investigate the spatial distribution property of land surface temperature (Ls), NDVI, and ETa over the San Joaquin valley. (2) Estimate actual evapotranspiration of almond class on pixel-by-pixel basis in the Central valley, California. (3) Comparison of actual Evapotranspiration obtained from SEBAL model with reference evapotranspiration (Eto) using Penman Monteiths method based on the procedures and available data from California Irrigation Management Information System (CIMIS) stations. The results of the regression between extracted land surface temperature, NDVI and, evapotranspiration show negative (-) correlation. On the other hand Ls possessed a slightly stronger negative correlation with the ETa than with NDVI for Almond class. The correlation coefficient of actual ETa estimates from remote sensing with Reference ETo from Penmann Monteith are 0.8571. ETa estimated for almond crop from SEBAL were found to be almost same with the CIMIS_Penman Monteith method with bias of 0.77 mm and mean percentage difference is 0.10%. These results indicate that combination of MASTER data with surface meteorological data could provide an efficient tool for the estimation of regional actual ET used for water resources and irrigation scheduling

  11. 76 FR 69895 - Approval and Promulgation of Implementation Plans; California; 2008 San Joaquin Valley PM2.5

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ...EPA is approving in part and disapproving in part state implementation plan (SIP) revisions submitted by California to provide for attainment of the 1997 fine particulate matter (PM2.5) national ambient air quality standards in the San Joaquin Valley (SJV). These SIP revisions are the SJV 2008 PM2.5 Plan (revised 2010 and 2011) and SJV-related provisions of the 2007 State......

  12. Geologic application of thermal inertia imaging using HCMM data. [Death Valley and Pisgah Crater, California and Goldfield, Nevada

    NASA Technical Reports Server (NTRS)

    Paley, H. N.; Kahle, A. B. (Principal Investigator)

    1980-01-01

    During the July to September 1980 quarter the final tapes were received completing the order and preliminary processing was done. Thermal Inertia images for each of the three test sites, Death Valley and Pisgah Crater, California and Goldfield, Nevada were created using registered HCMM day/night pairs and the JPL model. A comprehensive study and analysis of the geologic application of all acquired HCMM data is in progress.

  13. Insights into controls on hexavalent chromium in groundwater provided by environmental tracers, Sacramento Valley, California, USA

    USGS Publications Warehouse

    Manning, Andrew H.; Mills, Christopher; Morrison, Jean M.; Ball, Lyndsay B.

    2015-01-01

    Environmental tracers are useful for determining groundwater age and recharge source, yet their application in studies of geogenic Cr(VI) in groundwater has been limited. Environmental tracer data from 166 wells located in the Sacramento Valley, northern California, were interpreted and compared to Cr concentrations to determine the origin and age of groundwater with elevated Cr(VI), and better understand where Cr(VI) becomes mobilized and how it evolves along flowpaths. In addition to major ion and trace element concentrations, the dataset includes δ18O, δ2H, 3H concentration, 14C activity (of dissolved inorganic C), δ13C, 3He/4He ratio, and noble gas concentrations (He, Ne, Ar, Kr, Xe). Noble gas recharge temperatures (NGTs) were computed, and age-related tracers were interpreted in combination to constrain the age distribution in samples and sort them into six different age categories spanning from <60 yr old to >10,000 yr old. Nearly all measured Cr is in the form of Cr(IV). Concentrations range from <1 to 46 μg L−1, with 10% exceeding the state of California’s Cr(VI) maximum contaminant level of 10 μg L−1. Two groups with elevated Cr(VI) (⩾5 μg L−1) were identified. Group 1 samples are from the southern part of the valley and contain modern (<60 yr old) water, have elevated NO3− concentrations (>3 mg L−1), and commonly have δ18O values enriched relative to local precipitation. These samples likely contain irrigation water and are elevated due to accelerated mobilization of Cr(VI) in the unsaturated zone (UZ) in irrigated areas. Group 2 samples are from throughout the valley and typically contain water 1000–10,000 yr old, have δ18O values consistent with local precipitation, and have unexpectedly warm NGTs. Chromium(VI) concentrations in Group 2 samples may be elevated for multiple reasons, but the hypothesis most consistent with all available data (notably, the warm NGTs) is a relatively long UZ residence time due to

  14. Cenozoic tectonic reorganizations of the Death Valley region, southeast California and southwest Nevada

    USGS Publications Warehouse

    Fridrich, Christopher J.; Thompson, Ren A.

    2011-01-01

    The Death Valley region, of southeast California and southwest Nevada, is distinct relative to adjacent regions in its structural style and resulting topography, as well as in the timing of basin-range extension. Cenozoic basin-fill strata, ranging in age from greater than or equal to 40 to approximately 2 million years are common within mountain-range uplifts in this region. The tectonic fragmentation and local uplift of these abandoned basin-fills indicate a multistage history of basin-range tectonism. Additionally, the oldest of these strata record an earlier, pre-basin-range interval of weak extension that formed broad shallow basins that trapped sediments, without forming basin-range topography. The Cenozoic basin-fill strata record distinct stratigraphic breaks that regionally cluster into tight age ranges, constrained by well-dated interbedded volcanic units. Many of these stratigraphic breaks are long recognized formation boundaries. Most are angular unconformities that coincide with abrupt changes in depositional environment. Deposits that bound these unconformities indicate they are weakly diachronous; they span about 1 to 2 million years and generally decrease in age to the west within individual basins and regionally, across basin boundaries. Across these unconformities, major changes are found in the distribution and provenance of basin-fill strata, and in patterns of internal facies. These features indicate rapid, regionally coordinated changes in strain patterns defined by major active basin-bounding faults, coincident with step-wise migrations of the belt of active basin-range tectonism. The regionally correlative unconformities thus record short intervals of radical tectonic change, here termed "tectonic reorganizations." The intervening, longer (about 3- to 5-million-year) interval of gradual, monotonic evolution in the locus and style of tectonism are called "tectonic stages." The belt of active tectonism in the Death Valley region has abruptly

  15. Reconstruction of Flooding Events for the Central Valley, California from Instrumental and Documentary Weather Records

    NASA Astrophysics Data System (ADS)

    Dodds, S. F.; Mock, C. J.

    2009-12-01

    All available instrumental winter precipitation data for the Central Valley of California back to 1850 were digitized and analyzed to construct continuous time series. Many of these data, in paper or microfilm format, extend prior to modern National Weather Service Cooperative Data Program and Historical Climate Network data, and were recorded by volunteer observers from networks such as the US Army Surgeon General, Smithsonian Institution, and US Army Signal Service. Given incomplete individual records temporally, detailed documentary data from newspapers, personal diaries and journals, ship logbooks, and weather enthusiasts’ instrumental data, were used in conjunction with instrumental data to reconstruct precipitation frequency per month and season, continuous days of precipitation, and to identify anomalous precipitation events. Multilinear regression techniques, using surrounding stations and the relationships between modern and historical records, bridge timeframes lacking data and provided homogeneous nature of time series. The metadata for each station was carefully screened, and notes were made about any possible changes to the instrumentation, location of instruments, or an untrained observer to verify that anomalous events were not recorded incorrectly. Precipitation in the Central Valley varies throughout the entire region, but waterways link the differing elevations and latitudes. This study integrates the individual station data with additional accounts of flood descriptions through unique newspaper and journal data. River heights and flood extent inundating cities, agricultural lands, and individual homes are often recorded within unique documentary sources, which add to the understanding of flood occurrence within this area. Comparisons were also made between dam and levee construction through time and how waters are diverted through cities in natural and anthropogenically changed environments. Some precipitation that lead to flooding events that

  16. Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

    NASA Astrophysics Data System (ADS)

    Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

    2015-12-01

    Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

  17. SRTM Perspective View with Landsat Overlay: Mt. Pinos and San Joaquin Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Ask any astronomer where the best stargazing site in Southern California is, and chances are they'll say Mt. Pinos. In this perspective view generated from SRTM elevation data the snow-capped peak is seen rising to an elevation of 2,692 meters (8,831 feet), in stark contrast to the flat agricultural fields of the San Joaquin valley seen in the foreground. Below the summit, but still well away from city lights, the Mt. Pinos parking lot at 2,468 meters (8,100 feet) is a popular viewing area for both amateur and professional astronomers and astro-photographers. For visualization purposes, topographic heights displayed in this image are exaggerated two times.

    The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.

    Distance to Horizon: 176 kilometers (109 miles) Location: 34.83 deg. North lat., 119.25 deg. West lon. View: Toward the Southwest Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat

  18. BVOC and tropospheric ozone fluxes from an orange orchard in the California Central Valley

    NASA Astrophysics Data System (ADS)

    Fares, S.; Gentner, D. R.; Park, J.; Weber, R.; Karlik, J. F.; Goldstein, A. H.

    2010-12-01

    Citrus plants, especially oranges, are widely cultivated in the Central Valley of California and in many other countries experiencing Mediterranean climates. In many of these areas, orchards are often exposed to high levels of tropospheric ozone (O3) due to their location in polluted airsheds. Citrus take up O3 through their stomata and emit biogenic volatile organic compounds (BVOC), which can contribute to non-stomatal O3 removal through fast gas-phase reactions with O3. The study was performed in a navel orange orchard in Exeter, California. The CO2 & water fluxes, together with O3 uptake and BVOC emissions were measured continuously using eddy covariance techniques. Vertical concentration gradients of these compounds were also measured at 4 heights from the orchard floor to above the canopy. We observed high levels (up to 40 ppb) of volatile organic compounds including methanol, isoprene, monoterpenes, sesquiterpenes, and some additional oxygenated BVOC. Methanol dominated BVOC emissions (up to 5 nmol m-2 s-1) followed by acetone. Monoterpenes fluxes were also recorded during the all vegetative period, with the highest emissions taking place during flowering periods. The orchard represented a sink for ozone, with uptake rates on the order of 10 nmol m-2 s-1 during the central hours of the day. BVOC fluxes were highly temperature dependent, while ozone fluxes were more dependent on the physiology of the orchard, consistent with dominant removal occurring through the stomatal opening. The current research is aimed at: 1. Quantifying the uptake of O3 by citrus and partitioning it into stomatal and non-stomatal processes; 2. Quantifying the BVOC emissions and their dependence on physical and ecophysiological parameters.

  19. Fluxes of BVOC and tropospheric ozone from a Citrus orchard in the California Central Valley

    NASA Astrophysics Data System (ADS)

    Fares, S.; Park, J.; Weber, R.; Gentner, D. R.; Karlik, J. F.; Goldstein, A. H.

    2011-12-01

    Citrus plants, especially oranges, are widely cultivated in many countries experiencing Mediterranean climates. In many of these areas, orchards are often exposed to high levels of tropospheric ozone (O3) due to their location in polluted airsheds. Citrus take up O3 through their stomata and emit biogenic volatile organic compounds (BVOC), which can contribute to non-stomatal O3 removal through fast gas-phase reactions with O3. The study was performed in a valencia orange orchard in Exeter, California. From fall 2009 to winter 2010, CO2 & water fluxes, together with O3 uptake and BVOC emissions were measured continuously in situ with specific sensors (e.g. fast ozone analyzer and Proton Transfer Reaction Mass Spectrometer) using the eddy covariance techniques. Vertical concentration gradients of these compounds were also measured at 4 heights from the orchard floor to above the canopy. We observed high levels (up to 60 ppb) of volatile organic compounds including methanol, isoprene, monoterpenes, sesquiterpenes, and some additional oxygenated BVOC. Methanol dominated BVOC emissions (up to 7 nmol m-2 s-1) followed by acetone. Monoterpenes fluxes were also recorded during the all vegetative period, with the highest emissions taking place during flowering periods, and in general highly temperature dependent. The orchard represented a sink for ozone, with uptake rates on the order of 10 nmol m-2 s-1 during the central hours of the day. We found that BVOC played a major role in removing ozone through chemical reactions in the gas-phase, while only up to 40 % of ozone was removed via stomatal uptake. The current research aimed at investigating the fate of BVOC emitted from orange trees will help understanding the role of Citrus orchards in the complex oxidation mechanisms taking place in the polluted atmosphere of the San Joaquin Valley (California).

  20. Metals and trace elements in giant garter snakes (Thamnophis gigas) from the Sacramento Valley, California, USA

    USGS Publications Warehouse

    Wylie, G.D.; Hothem, R.L.; Bergen, D.R.; Martin, L.L.; Taylor, R.J.; Brussee, B.E.

    2009-01-01

    The giant garter snake (GGS; Thamnophis gigas) is a federally listed threatened species endemic to wetlands of the Central Valley of California. Habitat destruction has been the main factor in the decline of GGS populations, but the effects of contaminants on this species are unknown. To contribute to the recovery of these snakes, the U.S. Geological Survey (USGS) began studies of the life history and habitat use of GGSs in 1995. During a series of investigations conducted from 1995 to the present, specimens of dead GGSs were opportunistically collected from the Colusa National Wildlife Refuge (CNWR), the Natomas Basin, and other sites in northern California. Whole snakes were stored frozen for potential future analysis. As funding became available, we analyzed tissues of 23 GGSs to determine the concentrations of total mercury (Hg) and other trace elements in livers and concentrations of Hg in brains and tail clips. Mercury concentrations (??g/g, wet weight) ranged from 0.08 to 1.64 in livers, 0.01 to 0.18 in brains, and 0.02 to 0.32 in tail clips. In livers, geometric mean concentrations (??g/g, dry weight) of arsenic (25.7) and chromium (1.02) were higher than most values from studies of other snakes. Mercury concentrations in tail clips were positively correlated with concentrations in livers and brains, with the most significant correlations occurring at the Natomas Basin and when Natomas and CNWR were combined. Results indicate the value of using tail clips as a nonlethal bioindicator of contaminant concentrations. ?? 2008 US Government.

  1. Santa Clara Valley water district multi-aquifer monitoring-well site, Coyote Creek Outdoor Classroom, San Jose, California

    USGS Publications Warehouse

    Hanson, R.T.; Newhouse, M.W.; Wentworth, C.M.; Williams, C.F.; Noce, T.E.; Bennett, M.J.

    2002-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Santa Clara Valley Water District (SCVWD), has completed the first of several multiple-aquifer monitoring-well sites in the Santa Clara Valley. This site monitors ground-water levels and chemistry in the one of the major historic subsidence regions south of San Jose, California, at the Coyote Creek Outdoor Classroom (CCOC) (fig. 1) and provides additional basic information about the geology, hydrology, geochemistry, and subsidence potential of the upper- and lower-aquifer systems that is a major source of public water supply in the Santa Clara Valley. The site also serves as a science education exhibit at the outdoor classroom operated by SCVWD.

  2. Assessment of Computer-based Geologic Mapping of Rock Units in the LANDSAT-4 Scene of Northern Death Valley, California

    NASA Technical Reports Server (NTRS)

    Short, N. M.

    1984-01-01

    Results from a series of geologic classifications conducted on a thematic mapper subscene of the northern Death Valley, California are reported. Measurements of accuracy are made through comparison with the 1977 edition of the Death Valley geologic sheet. This employs a simplified map version which is registered by computer to the image data base, allowing a pixel by pixel match with the classified scene. The results show accuracy ranges from 36 to 79% depending on the type of classifier used and the statistical adjustments made to the data. Accuracy values in identifying geologic units were 2 to 3 times higher for those in the relatively flat valleys than for units in the rugged mountainous terrain. Improvements in accuracy will be sought by correcting for slope/aspect variations in mountainous terrain using topographic data recorded in Defense Mapping Agency (DMA) tapes. The above classification results will also be compared with ratio and principal component image classifications made from the same scene.

  3. Map showing depth to pre-Cenozoic basement in the Death Valley ground-water model area, Nevada and California

    SciTech Connect

    Blakely, R.J.; Ponce, D.A.

    2002-03-12

    This map shows the depth to pre-Cenozoic basement in the Death Valley ground-water model area. It was prepared utilizing gravity (Ponce and others, 2001), geologic (Jennings and others, 1977; Stewart and Carlson, 1978), and drill-hole information. Geophysical investigations of the Death Valley ground-water model area are part of an interagency effort by the U.S. Geological Survey (USGS) and the U.S. Department of Energy (Interagency Agreement DE-AI08-96NV11967) to help characterize the geology and hydrology of southwestern Nevada and parts of California. The Death Valley ground-water model is located between lat 35 degrees 00' and 38 degrees 15' N., and long 115 degrees and 118 degrees W.

  4. Marine magnetic anomaly 33 34 identified in the Upper Cretaceous of the Great Valley Sequence of California

    NASA Astrophysics Data System (ADS)

    Ward, Peter D.; Verosub, Kenneth L.; Haggart, James W.

    1983-02-01

    An interval of reversed magnetic polarity has been located in Upper Cretaceous rocks of the Great Valley Sequence of California. The interval has been found at four sites, two on each side of the Sacramento Valley. In each case, the reversed interval is associated with the same ammonite local range zone. Firm biostratigraphic correlation and the structure of the magnetic polarity time scale allow us to determine that the reversed interval corresponds to marine magnetic anomaly 33 34 and represents the lower part of the Campanian Stage. The reversed interval serves as a marker horizon linking the different faunal assemblages and sedimentary facies of the Great Valley Sequence. It also provides the first direct correlation of provincial biostratigraphic zones of the North Pacific province with the Cretaceous stages in Europe.

  5. A century of plant virus management in the Salinas valley of California, 'East of Eden'.

    PubMed

    Wisler, G C; Duffus, J E

    2000-11-01

    The mild climate of the Salinas Valley, CA lends itself well to a diverse agricultural industry. However, the diversity of weeds, crops and insect and fungal vectors also provide favorable conditions for plant virus disease development. This paper considers the incidence and management of several plant viruses that have caused serious epidemics and been significant in the agricultural development of the Salinas Valley during the 20th century. Beet curly top virus (BCTV) almost destroyed the newly established sugarbeet industry soon after its establishment in the 1870s. A combination of resistant varieties, cultural management of beet crops to provide early plant emergence and development, and a highly coordinated beet leafhopper vector scouting and spray programme have achieved adequate control of BCTV. These programmes were first developed by the USDA and still operate. Lettuce mosaic virus was first recognized as causing a serious disease of lettuce crops in the 1930s. The virus is still a threat but it is controlled by a lettuce-free period in December and a seed certification programme that allows only seed lots with less than one infected seed in 30000 to be grown. 'Virus Yellows' is a term used to describe a complex of yellows inducing viruses which affect mainly sugarbeet and lettuce. These viruses include Beet yellows virus and Beet western yellows virus. During the 1950s, the complex caused significant yield losses to susceptible crops in the Salinas Valley. A beet-free period was introduced and is still used for control. The fungus-borne rhizomania disease of sugarbeet caused by Beet necrotic yellow vein virus was first detected in Salinas Valley in 1983. Assumed to have been introduced from Europe, this virus has now become widespread in California wherever beets are grown and crop losses can be as high as 100%. Movement of infested soil and beets accounts for its spread throughout the beet-growing regions of the United States. Control of rhizomania

  6. Efficient crop type mapping based on remote sensing in the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Zhong, Liheng

    Most agricultural systems in California's Central Valley are purposely flexible and intentionally designed to meet the demands of dynamic markets. Agricultural land use is also impacted by climate change and urban development. As a result, crops change annually and semiannually, which makes estimating agricultural water use difficult, especially given the existing method by which agricultural land use is identified and mapped. A minor portion of agricultural land is surveyed annually for land-use type, and every 5 to 8 years the entire valley is completely evaluated. So far no effort has been made to effectively and efficiently identify specific crop types on an annual basis in this area. The potential of satellite imagery to map agricultural land cover and estimate water usage in the Central Valley is explored. Efforts are made to minimize the cost and reduce the time of production during the mapping process. The land use change analysis shows that a remote sensing based mapping method is the only means to map the frequent change of major crop types. The traditional maximum likelihood classification approach is first utilized to map crop types to test the classification capacity of existing algorithms. High accuracy is achieved with sufficient ground truth data for training, and crop maps of moderate quality can be timely produced to facilitate a near-real-time water use estimate. However, the large set of ground truth data required by this method results in high costs in data collection. It is difficult to reduce the cost because a trained classification algorithm is not transferable between different years or different regions. A phenology based classification (PBC) approach is developed which extracts phenological metrics from annual vegetation index profiles and identifies crop types based on these metrics using decision trees. According to the comparison with traditional maximum likelihood classification, this phenology-based approach shows great advantages

  7. Estimation of Seismic and Aseismic Deformation in Mexicali Valley, Baja California, Mexico, in the 2006-2009 Period, Using Precise Leveling, DInSAR, Geotechnical Instruments Data, and Modeling

    NASA Astrophysics Data System (ADS)

    Sarychikhina, Olga; Glowacka, Ewa; Robles, Braulio; Nava, F. Alejandro; Guzmán, Miguel

    2015-11-01

    Ground deformation and seismicity in Mexicali Valley, Baja California, Mexico, the southern part of the Mexicali-Imperial valley, are influenced by active tectonics and human activity. In this study, data from two successive leveling surveys in 2006 and 2009/2010 are used to estimate the total deformation occurred in Mexicali Valley during 2006-2009. The leveling data span more than 3.5 years and include deformation from several natural and anthropogenic sources that acted at different temporal and spatial scales during the analyzed period. Because of its large magnitude, the aseismic anthropogenic deformation caused by fluid extraction in the Cerro Prieto geothermal field obscures the deformation caused by other mechanisms and sources. The method of differential interferograms stacking was used to estimate the aseismic (interseismic tectonic and anthropogenic) components of the observed displacement, using SAR images, taken in 2007 during a period when no significant seismicity occurred in the study area. After removing the estimated aseismic signal from the leveling data, residual vertical displacement remained, and to identify possible sources and mechanisms of this displacement, a detailed analysis of records from tiltmeters and creepmeters was performed. The results of this analysis suggest that the residual displacement is mainly caused by moderate-sized seismicity in the area of study. Modeling of the vertical ground deformation caused by the coseismic slip on source fault (primary mechanism) of the two most important earthquakes, May 24, 2006 (Mw = 5.4) and December 30, 2009 (Mw = 5.8), was performed. The modeling results, together with the analysis of geotechnical instruments data, suggests that this moderate-sized seismicity influences the deformation in the study area by coseismic slip on the source fault, triggered slip on secondary faults, and soft sediments deformation.

  8. A western thalweg of the Princeton Valley submarine canyon system as a reservoir and a trap near Willows, California

    SciTech Connect

    Blake, R.G. ); Bainer, R.W.

    1990-05-01

    The Princeton Valley submarine canyon system has long been an important reservoir and trapping mechanism in the northern Sacramento Valley, California. Recently a western thalweg of the system, identified north of Willows, California, has proven to be a significant trapping mechanism for gas in truncated Kione Formation sandstones. Both Upper Cretaceous Kione Formation and Paleocene Princeton Valley sandstones are exploratory objectives in the area and are productive in existing wells. The Kione Formation, a sand-rich deltaic sequence approximately 2,000 ft thick, has been truncated to the west by the Princeton Valley submarine canyon system. The canyon (gorge) has been subsequently filed with primarily impermeable shales, providing a trap for migrating gases in the truncated sands. The trend was discovered in 1977 by Shell Oil Company based on seismic and was the first substantiated evidence of a western thalweg of the Princeton Gorge in the Willows area. To date, four wells have been completed along the trend and current exploratory efforts are attempting to follow the gorge trend.

  9. A public health issue related to collateral seismic hazards: The valley fever outbreak triggered by the 1994 Northridge, California earthquake

    USGS Publications Warehouse

    Jibson, R.W.

    2002-01-01

    Following the 17 January 1994 Northridge. California earthquake (M = 6.7), Ventura County, California, experienced a major outbreak of coccidioidomycosis (CM), commonly known as valley fever, a respiratory disease contracted by inhaling airborne fungal spores. In the 8 weeks following the earthquake (24 January through 15 March), 203 outbreak-associated cases were reported, which is about an order of magnitude more than the expected number of cases, and three of these cases were fatal. Simi Valley, in easternmost Ventura County, had the highest attack rate in the county, and the attack rate decreased westward across the county. The temporal and spatial distribution of CM cases indicates that the outbreak resulted from inhalation of spore-contaminated dust generated by earthquake-triggered landslides. Canyons North East of Simi Valley produced many highly disrupted, dust-generating landslides during the earthquake and its aftershocks. Winds after the earthquake were from the North East, which transported dust into Simi Valley and beyond to communities to the West. The three fatalities from the CM epidemic accounted for 4 percent of the total earthquake-related fatalities.

  10. Abundance and sexual size dimorphism of the giant gartersnake (Thamnophis gigas) in the Sacramento valley of California

    USGS Publications Warehouse

    Wylie, G.D.; Casazza, M.L.; Gregory, C.J.; Halstead, B.J.

    2010-01-01

    The Giant Gartersnake (Thamnophis gigas) is restricted to wetlands of the Central Valley of California. Because of wetland loss in this region, the Giant Gartersnake is both federally and state listed as threatened. We conducted markrecapture studies of four populations of the Giant Gartersnake in the Sacramento Valley (northern Central Valley), California, to obtain baseline data on abundance and density to assist in recovery planning for this species. We sampled habitats that ranged from natural, unmanaged marsh to constructed managed marshes and habitats associated with rice agriculture. Giant Gartersnake density in a natural wetland (1.90 individuals/ha) was an order of magnitude greater than in a managed wetland subject to active season drying (0.17 individuals/ha). Sex ratios at all sites were not different from 1 1, and females were longer and heavier than males. Females had greater body condition than males, and individuals at the least disturbed sites had significantly greater body condition than individuals at the managed wetland. The few remaining natural wetlands in the Central Valley are important, productive habitat for the Giant Gartersnake, and should be conserved and protected. Wetlands constructed and restored for the Giant Gartersnake should be modeled after the permanent, shallow wetlands representative of historic Giant Gartersnake habitat. ?? 2010 Society for the Study of Amphibians and Reptiles.

  11. A preliminary investigation of the variables affecting the distribution of giant gartersnakes (Thamnophis gigas) in the Sacramento Valley, California

    USGS Publications Warehouse

    Halstead, Brian J.; Skalos, Shannon M.; Casazza, Michael L.; Wylie, Glenn D.

    2015-01-01

    Giant gartersnakes (Thamnophis gigas) comprise a species of rare, semi-aquatic snake precinctive to the Central Valley of California. Because of the loss of more than 90% of their natural habitat, giant gartersnakes are listed as Threatened by the United States and California endangered species acts. Little is known, however, about the distribution of giant gartersnakes in the Sacramento Valley, which is where most extant populations occur. We conducted detection-nondetection surveys for giant gartersnakes throughout the rice-growing regions of the Sacramento Valley, and used occupancy models to examine evidence for the effects of landscape-scale GIS-derived variables, local habitat and vegetation composition, and prey communities on patterns of giant gartersnake occurrence. Although our results are based on a relatively small sample of sites, we found that distance to historic marsh, relative fish count, and an interaction of distance to historic marsh with proportion of habitat composed of submerged vegetation were important variables for explaining occupancy of giant gartersnakes. In particular, giant gartersnakes were more likely to occur closer to historic marsh and where relatively fewer fish were captured in traps. At locations in or near historic marsh, giant gartersnakes were more likely to occur in areas with less submerged vegetation, but this relationship was reversed (and more uncertain) at sites distant from historic marsh. Additional research with a larger sample of sites would further elucidate the distribution of giant gartersnakes in the Sacramento Valley.

  12. An apparent shear zone trending north-northwest across the Mojave Desert into Owens Valley, eastern California

    SciTech Connect

    Savage, J.C.; Lisowski, M.; Prescott, W.H. )

    1990-11-01

    Strain rates measured at four geodetic networks in eastern California situated between northern Owens Valley and Transverse Ranges along a small circle drawn about the Pacific-North America pole of rotation are remarkably consistent. Each exhibits 0.14 {mu}rad/yr simple right-lateral engineering-shear-strain accumulation across the local vertical plane tangent to the small circle. Local faults (e.g., Owens Valley, Garlock, Helendale) traversing these networks are not as closely aligned with the vertical planes of maximum shear-strain accumulation as is the local tangent to the small circle. A fifth network slightly east of the small circle shows no significant strain accumulation. Thus, a shear zone trending N35{degree}W from near the eastern end of the big bend of the San Andreas fault to northern Owens Valley is indicated by these data. This corresponds to the Eastern California shear zone proposed on geological evidence by Dokka and Travis. The shear zone carries {approximately}8 mm/yr of the Pacific-North America relative plate motion from the San Andreas fault north-northwest across the Mojave Desert into Owens Valley and the northern Basin and Range province. The shear zone observed at the surface may be a manifestation of a through-going subcrustal fault.

  13. Long-term sand supply to Coachella Valley Fringe-toed Lizard Habitat in the Northern Coachella Valley, California

    USGS Publications Warehouse

    Griffiths, Peter G.; Webb, Robert H.; Lancaster, Nicholas; Kaehler, Charles A.; Lundstrom, Scott C.

    2002-01-01

    The Coachella Valley fringe-toed lizard (Uma inornata) is a federally listed threatened species that inhabits active sand dunes in the vicinity of Palm Springs, California. The Whitewater Floodplain and Willow Hole Reserves provide some of the primary remaining habitat for this species. The sediment-delivery system that creates these active sand dunes consists of fluvial depositional areas fed episodically by ephemeral streams. Finer fluvial sediments (typically sand size and finer) are mobilized in a largely unidirectional wind field associated with strong westerly winds through San Gorgonio Pass. The fluvial depositional areas are primarily associated with floodplains of the Whitewater?San Gorgonio Rivers and Mission Creek?Morongo Wash; other small drainages also contribute fluvial sediment to the eolian system. The eolian dunes are transitory as a result of unidirectional sand movement from the depositional areas, which are recharged with fine-grained sediment only during episodic floods that typically occur during El Ni?o years. Eolian sand moves primarily from west to east through the study area; the period of maximum eolian activity is April through June. Wind speed varies diurnally, with maximum velocities typically occurring during the afternoon. Development of alluvial fans, alteration of stream channels by channelization, in-stream gravel mining, and construction of infiltration galleries were thought to reduce the amount of fluvial sediment reaching the depositional areas upwind of Uma habitat. Also, the presence of roadways, railroads, and housing developments was thought to disrupt or redirect eolian sand movement. Most of the sediment yield to the fluvial system is generated in higher elevation areas with little or no development, and sediment yield is affected primarily by climatic fluctuations and rural land use, particularly livestock grazing and wildfire. Channelization benefits sediment delivery to the depositional plains upwind of the reserves

  14. Mineral resources and mineral resource potential of the Saline Valley and Lower Saline Wilderness Study Areas, Inyo County, California

    SciTech Connect

    Wrucke, C.T.; Marsh, S.P.; Raines, G.L.; Werschky, R.S.; Blakely, R.J.; Hoover, D.B.; McHugh, E.L.; Rumsey, C.M.; Gaps, R.S.; Causey, J.D.

    1984-01-01

    This report presents the results of a mineral survey of the Saline Valley Wilderness Study Area and the Lower Saline Wilderness Study Area, California Desert Conservation Area, Inyo County, California. The Saline Valley Wilderness Study Area and the Lower Saline Wilderness Study Area were studied in 1981-83 using geologic, geochemical, remote sensing, and geophysical surveys and the examination of mines and prospects to evaluate mineral resources and the potential for mineral resources. The Saline Valley Wilderness Study Area has a high potential for the occurrence of gold resources in two areas. One area, largely outside the study area, is in the vicinity of the Crater mine in the Last Chance Range, and it has potential for the occurrence of gold in a disseminated deposit in an epithermal environment. The other area is in Marble Canyon in the western part of the study area, and it has high potential for the occurrence of gold placer deposits. Marble Canyon also has a moderate potential for gold in placer deposits downstream from the area of high potential. Seven areas, scattered from the Inyo Mountains to the Last Chance Range, have a low potential for the occurrence of gold in disseminated deposits, and one area that lies astride the border of Death Valley National Monument has a low potential for the occurrence of gold in vein deposits. The southern end of Eureka Valley has a low potential for the occurrence of lithium and uranium resources in buried sedimentary deposits for the occurrence of lithium and uranium resources in buried sedimentary deposits beneath the valley floor. Demonstrated resources of native sulfur exist at the Crater mine but no resource potential was identified nearby in adtacent parts of the study area. 3 figs. (ACR)

  15. Education and the New Imperialism

    ERIC Educational Resources Information Center

    Tikly, Leon

    2004-01-01

    The aim of the article is to discuss the role of education in relation to the new imperialism. The article begins by explaining what is meant by the term the "new imperialism" and how it differs from older forms of European imperialism characterized by colonial rule. The new imperialism is presented as having material and discursive aspects…

  16. Scenario earthquake hazards for the Long Valley Caldera-Mono Lake area, east-central California

    USGS Publications Warehouse

    Chen, Rui; Branum, David M.; Wills, Chris J.; Hill, David P.

    2014-01-01

    As part of the U.S. Geological Survey’s (USGS) multi-hazards project in the Long Valley Caldera-Mono Lake area, the California Geological Survey (CGS) developed several earthquake scenarios and evaluated potential seismic hazards, including ground shaking, surface fault rupture, liquefaction, and landslide hazards associated with these earthquake scenarios. The results of these analyses can be useful in estimating the extent of potential damage and economic losses because of potential earthquakes and in preparing emergency response plans. The Long Valley Caldera-Mono Lake area has numerous active faults. Five of these faults or fault zones are considered capable of producing magnitude ≥6.7 earthquakes according to the Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2) developed by the 2007 Working Group of California Earthquake Probabilities (WGCEP) and the USGS National Seismic Hazard Mapping (NSHM) Program. These five faults are the Fish Slough, Hartley Springs, Hilton Creek, Mono Lake, and Round Valley Faults. CGS developed earthquake scenarios for these five faults in the study area and for the White Mountains Fault to the east of the study area. Earthquake scenarios are intended to depict the potential consequences of significant earthquakes. They are not necessarily the largest or most damaging earthquakes possible. Earthquake scenarios are both large enough and likely enough that emergency planners should consider them in regional emergency response plans. Earthquake scenarios presented here are based on fault geometry and activity data developed by the WGCEP, and are consistent with the 2008 Update of the United States National Seismic Hazard Maps (NSHM).For the Hilton Creek Fault, two alternative scenarios were developed in addition to the NSHM scenario to account for different opinions in how far north the fault extends into the Long Valley Caldera. For each scenario, ground motions were calculated using the current standard practice

  17. Geohydrology of part of the Round Valley Indian Reservation, Mendocino County, California

    USGS Publications Warehouse

    Muir, K.S.; Webster, Dwight Albert

    1977-01-01

    The Round Valley Indian Reservation in northern California obtains most of its water from the ground-water reservoir. The ground-water reservoir is made up of continental deposits, alluvium, and stream-channel deposits ranging in age from Pliocene to Holocene. Most of the water is pumped from the alluvium. Most ground water (about 20,000 acre-feet or 25 cubic hectometers per year) is derived from stream seepage. Natural discharge (discharge to streams, evapotranspiration, and underflow) has averaged about 21,000 acre-feet per year. Pumping and flow from artesian wells has averaged about 2,750 acre-feet per year. Ground water occurs in both confined and unconfined aquifers. The ground-water reservoir is full, and about 230,000 acre-feet of water is stored in the depth interval 10-200 feet. The water is chemically and biologically suitable for domestic or irrigation use, although hardness is high for domestic use and, locally, dissolved iron is a problem. There is potential for developing additional ground-water supplies. (Woodard-USGS)

  18. Land subsidence in the Santa Clara Valley, California as of 1980

    USGS Publications Warehouse

    Poland, J.F.; Ireland, R.L.

    1984-01-01

    From 1916 to 1966 in the San Jose area of Santa Clara Valley, California, deficient rainfall and runoff was accompanied by a fourfold increase in groundwater withdrawals. In response the artesian head declined 180-240 ft. The land surface subsided 12.7 ft in San Jose, due to compaction of the fine-grained compressible beds. The subsidence resulted in flooding of lands, and the compaction of the sediments caused compressional failure of many well casings. From 1967 to 1975, the artesian head recovered 70 to 100 feet due to a fivefold increase in surface water imports, favorable local water supply, decreased withdrawal, and increased recharge. In 1960, the Geological Survey installed extensometers in core holes 1,000 ft deep in San Jose and Sunnyvale. Measurements of compaction of the confined aquifer system obtained from these extensometers demonstrate the marked decrease in rate of compaction in response to the major head recovery since 1967. In San Jose the rate decreased from about 1 ft/yr in 1961 to 0.1 ft/yr in 1973. The subsidence has been stopped by raising the artesian head in the aquifers until it equaled or exceeded the maximum pore pressures in the fine-grained beds. However, the subsidence will recommence if the artesian head is drawn down appreciably below the levels of 1971-73. (USGS)

  19. Modeling nitrate at domestic and public-supply well depths in the Central Valley, California

    USGS Publications Warehouse

    Nolan, Bernard T.; Gronberg, JoAnn M.; Faunt, Claudia C.; Eberts, Sandra M.; Belitz, Ken

    2014-01-01

    Aquifer vulnerability models were developed to map groundwater nitrate concentration at domestic and public-supply well depths in the Central Valley, California. We compared three modeling methods for ability to predict nitrate concentration >4 mg/L: logistic regression (LR), random forest classification (RFC), and random forest regression (RFR). All three models indicated processes of nitrogen fertilizer input at the land surface, transmission through coarse-textured, well-drained soils, and transport in the aquifer to the well screen. The total percent correct predictions were similar among the three models (69–82%), but RFR had greater sensitivity (84% for shallow wells and 51% for deep wells). The results suggest that RFR can better identify areas with high nitrate concentration but that LR and RFC may better describe bulk conditions in the aquifer. A unique aspect of the modeling approach was inclusion of outputs from previous, physically based hydrologic and textural models as predictor variables, which were important to the models. Vertical water fluxes in the aquifer and percent coarse material above the well screen were ranked moderately high-to-high in the RFR models, and the average vertical water flux during the irrigation season was highly significant (p < 0.0001) in logistic regression.

  20. Comparison of Two Parametric Methods to Estimate Pesticide Mass Loads in California's Central Valley

    USGS Publications Warehouse

    Saleh, D.K.; Lorenz, D.L.; Domagalski, J.L.

    2011-01-01

    Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations. ?? 2010 American Water Resources Association. This article is a US Government work and is in the public domain in the USA.

  1. Comparison of two parametric methods to estimate pesticide mass loads in California's Central Valley

    USGS Publications Warehouse

    Saleh, Dina K.; Lorenz, David L.; Domagalski, Joseph L.

    2011-01-01

    Mass loadings were calculated for four pesticides in two watersheds with different land uses in the Central Valley, California, by using two parametric models: (1) the Seasonal Wave model (SeaWave), in which a pulse signal is used to describe the annual cycle of pesticide occurrence in a stream, and (2) the Sine Wave model, in which first-order Fourier series sine and cosine terms are used to simulate seasonal mass loading patterns. The models were applied to data collected during water years 1997 through 2005. The pesticides modeled were carbaryl, diazinon, metolachlor, and molinate. Results from the two models show that the ability to capture seasonal variations in pesticide concentrations was affected by pesticide use patterns and the methods by which pesticides are transported to streams. Estimated seasonal loads compared well with results from previous studies for both models. Loads estimated by the two models did not differ significantly from each other, with the exceptions of carbaryl and molinate during the precipitation season, where loads were affected by application patterns and rainfall. However, in watersheds with variable and intermittent pesticide applications, the SeaWave model is more suitable for use on the basis of its robust capability of describing seasonal variation of pesticide concentrations.

  2. The 1979 Homestead Valley earthquake sequence, California: control of aftershocks and postseismic deformation.

    USGS Publications Warehouse

    Stein, R.S.; Lisowski, M.

    1983-01-01

    The coseismic slip and geometry of the March 15, 1979, Homestead Valley, California, earthquake sequence are well constrained by precise horizontal and vertical geodetic observations and by data from a dense local seismic network. These observations indicate 0.52 + or - 0.10 m of right-lateral slip and 0.17 + or - 0.04 m of reverse slip on a buried vertical 6-km-long and 5-km-deep fault and yield a mean static stress drop of 7.2 + or -1.3 MPa. The largest shock had Ms = 5.6. Observations of the ground rupture revealed up to 0.1 m of right-lateral slip on two mapped faults that are subparallel to the modeled seismic slip plane. In the 1.9 years since the earthquakes, geodetic network displacements indicate that an additional 60+ or -10 mm of postseismic creep took place. The rate of postseismic shear strain (0.53 + or - 0.13 mu rad/yr) measured within a 30 X 30-km network centered on the principal events was anomalously high compared to its preearthquake value and the postseismic rate in the adjacent network. This transient cannot be explained by postseismic slip on the seismic fault but rather indicates that broadside release of strain followed the earthquake sequence. -Authors

  3. Fall and winter foods of northern pintails in the Sacramento Valley, California

    USGS Publications Warehouse

    Miller, M.R.

    1987-01-01

    Food habits of northern pintails (Anas acuta) were investigated on 3 national wildlife refuges in the western portion of the Sacramento Valley, California, from August to March 1979-82. Pintails consumed 97% (aggregate % dry wt) plant food during diurnal foraging on national wildlife refuge rice, summer-irrigated, and summer-dry habitats from August through January. Invertebrate use increased to 28.9-65.6% of the diet in these habitats during February and March. Rice, swamp timothy (Heleochloa schoenoides), flatsedges (Cyperus spp.), common barnyardgrass (Echinochloa crusgalli), southern naiad (Najas guadalupensis), and smartweed (Polygonum spp.) seeds, miscellaneous vegetation, snails (Gastropoda), and midge (Diptera) and water beetle (Coleoptera) larvae were most important. These foods usually were taken proportional to or greater than availability. Rice was the most important food of pintails feeding nocturnally off the refuges in harvested rice fields from October through January (99.7%) and February and March (63%; barnyardgrass formed 31% of the diet). In August and October, some pintails consumed invertebrates or bulrush (Scirpus spp. ) seedlings in marshes soon after feeding in refuge rice (Aug) or harvested commercial rice fields (Oct), thereby increasing dietary protein. In late winter, females and males obtained similar (P > 0.05) percentages of invertebrates from refuge habitats. Important dietary seeds and invertebrates contained high protein or metabolizable energy content. Management should maintain adequate seed production in fall and mid-winter and invertebrate biomass in late winter.

  4. Conjunctive management of groundwater and surface water resources in the San Joaquin Valley of California

    SciTech Connect

    Quinn, N.W.T.

    1992-01-01

    The San Joaquin-Tulare Conjunctive Use Model (SANTUCM) was developed to evaluate possible long-term scenarios for long term management of drainage and drainage related problems in the western San Joaquin Valley of California. The unique aspect of the conjunctive use model is its coupling of a surface water delivery operations model with a regional groundwater model. A salinity model has been added to utilize surface water model output and allow assessment of compliance with State Water Resources Control Board water quality objectives for the San Joaquin River. The results of scenario runs, performed to data, using the SANTUCM model show table lowering and consequent drainage reduction can be achieved through a combination of source control, land retirement and regional groundwater pumping. The model also shows that water transfers within the existing distribution system are technically feasible and might allow additional releases to be made from Friant Dam for water quality maintenance in the San Joaquin River. However, upstream of Mendota Pool, considerable stream losses to the aquifer are anticipated, amounting to as much as 70% of in-stream flow.

  5. Structure and stratigraphy beneath a young phreatic vent: South Inyo Crater, Long Valley caldera, California

    SciTech Connect

    Eichelberger, J.C.; Vogel, T.A.; Younker, L.W.; Dan Miller, C.; Heiken, G.H.; Wohletz, K.H.

    1988-11-10

    An 861-m-long hole has been cored on a slanted trajectory that passed directly beneath South Inyo Crater in the west moat of Long valley Caldera, California. The purpose of the hole was to investigate the magmatic behavior that led to surface deformation and phreatic activity during the 600-year-old eruption of the Inyo vent chain. The hole was sited 216 m southwest of the crater, passed beneath its center at a depth of 566 m, and terminated 79 m northeast of the crater center at a depth of 810 m. Metamorphic basement was encountered at a depth of 779 m. The volcanic and sedimentary sequence consists solely of post-Bishop Tuff caldera fill, including 319 m of moat basalt and 342 m of early rhyolite, and is nearly 900 m thinner than in a Unocal Corporation well 900 m to the southeast. Apparently, a major fault lies between the two holes and forms part of the western structural boundary of the caldera, 3--4 km inboard of its topographic boundary. Breccia zones that intrude the caldera fill were intersected at 12.0--9.3 m and 1.2--0.8 m SW and 8.5--25.1 m NE of the crater center.

  6. Evidence for dyke intrusion earthquake mechanisms near long valley caldera, California

    USGS Publications Warehouse

    Julian, B.R.

    1983-01-01

    A re-analysis of the magnitude 6 earthquakes that occurred near Long Valley caldera in eastern California on 25 and 27 May 1980, suggests that at least two of them, including the largest, were probably caused by fluid injection along nearly vertical surfaces and not by slip on faults. Several investigators 1,2 have reported difficulty in explaining both the long-period surface-wave amplitudes and phases and the locally recorded short-period body-wave first motions from these events, using conventional double-couple (shear fault) source models. They attributed this difficulty to: (1) complex sources, not representable by single-fault models; (2) artefacts of the analysis methods used; or (3) effects of wave propagation through hypothetical structures beneath the caldera. We show here that the data agree well with the predictions for a compensated linear-vector dipole (CLVD) equivalent-force system3 with its principal extensional axis horizontal and trending N 55-65?? E. Such a mechanism is what would be expected for fluid injection into dykes striking N 25-35?? W, which is the approximate strike of numerous normal faults in the area. ?? 1983 Nature Publishing Group.

  7. Modeling nitrate at domestic and public-supply well depths in the Central Valley, California.

    PubMed

    Nolan, Bernard T; Gronberg, JoAnn M; Faunt, Claudia C; Eberts, Sandra M; Belitz, Ken

    2014-05-20

    Aquifer vulnerability models were developed to map groundwater nitrate concentration at domestic and public-supply well depths in the Central Valley, California. We compared three modeling methods for ability to predict nitrate concentration >4 mg/L: logistic regression (LR), random forest classification (RFC), and random forest regression (RFR). All three models indicated processes of nitrogen fertilizer input at the land surface, transmission through coarse-textured, well-drained soils, and transport in the aquifer to the well screen. The total percent correct predictions were similar among the three models (69-82%), but RFR had greater sensitivity (84% for shallow wells and 51% for deep wells). The results suggest that RFR can better identify areas with high nitrate concentration but that LR and RFC may better describe bulk conditions in the aquifer. A unique aspect of the modeling approach was inclusion of outputs from previous, physically based hydrologic and textural models as predictor variables, which were important to the models. Vertical water fluxes in the aquifer and percent coarse material above the well screen were ranked moderately high-to-high in the RFR models, and the average vertical water flux during the irrigation season was highly significant (p < 0.0001) in logistic regression. PMID:24779475

  8. Mortality following cotton defoliation: San Joaquin Valley, California, 1970-1990.

    PubMed

    Ames, R G; Gregson, J

    1995-07-01

    A proportional mortality study comparing the cotton-growing areas of the San Joaquin Valley with the rest of the State of California was performed by the Office of Environmental Health Hazard Assessment as a continuation of earlier studies related to mercaptan-releasing pesticides. This mortality study found a pattern of increased proportion of "respiratory causes" mortality (ICD codes 460-519), statistically significant at less than the .05 probability level, for 15 of 21 years between 1970 and 1990, for the time period during and immediately following cotton defoliation. Defoliants which have the potential to produce acute symptoms include DEF and Folex, both of which release odorous butyl mercaptan gas as a degradation product. This paper tests the hypothesis that exposure to cotton defoliant breakdown products may be associated with a disproportionate increase in mortality. Prediction of the mortality proportions by pounds of DEF and Folex used was not statistically significant in the unadjusted models or in models adjusted for air pollution variables. One air pollution adjustment factor, total suspended particulates, was a statistically significant independent mortality proportion predictor. This finding suggests that total suspended particulates, not defoliants, may be related to mortality differentials during defoliation season. Possible confounding by demographic variation of the counties was not controlled in the analysis. PMID:7552465

  9. Flood data for the Sacramento River and Butte Basin, Sacramento Valley, California, 1980-90

    USGS Publications Warehouse

    Harmon, Jerry G.

    1994-01-01

    Floodflows and peak states of floods were measured and channel cross sections were surveyed at sites along the Sacramento River and in Butte Basin, Sacramento Valley, California, during 1980-90 to document magnitudes of flooding and channel changes. The study reach extends from rivermile 200 near Hamilton City to rivermile 134 near Meridian. Data were collected for each flood at about 70 sites that include streamf-flow gages, crest-stage gages, bridges and road overflows on State Highway 162 east of Butte City, and locations of historical high- water marks. Six cross sections of the river between rivermiles 193.7 near Big Chico Creek and 183.3 near Ordbend were surveyed annually during calendar years 1981-84, and 1986-90. Floodflows (peak flow 157,000 cubic feet per second) almost equaled the design flow capacity of the river at Butte City on March 2, 1983, when the peak stage of 93.0 feet was 5 feet below the top of the levee. This was the largest flood recorded at Butte City during 1980- 90. The most recent flood occurred February 18-19, 1986, when the peak stage in the river at Butte City was 92.0 feet and the peak flow was 145,000 cubic feet per second.

  10. Distribution of selenium in soils of agricultural fields, western San Joaquin Valley, California

    USGS Publications Warehouse

    Fujii, Roger; Deverel, S.J.; Hatfield, D.B.

    1988-01-01

    Soils from three agricultural fields in the Panoche Creek alluvial fan area in the western San Joaquin Valley, California, were analyzed for soluble, adsorbed, and total concentrations of selenium (Se) to assess the distribution and forms of Se in relation to the leaching of Se from soils. This assessment is needed to evaluate the importance of soil Se in affecting ground water concentrations. Soil samples were collected from three fields with drainage systems of different ages (6, 15, 1.5 yr) and different Se concentrations in drain water (58, 430, 3700 µg L−1, respectively). Concentrations of soluble Se and salinity were highest in soils from the field drained for 1.5 yr and lowest in the field drained for 6 yr. Of the total concentration of soil Se from all three fields, the proportion of adsorbed and soluble Se ranged from 1 to 11% and 2 > 0.68) in saturation extracts of soils sampled from below the water table. In contrast, most soluble salts and Se apparently have been leached from the unsaturated soils in the fields drained for 6 and 15 yr. For the leached soils, dissolution and precipitation of evaporite minerals containing Se may no longer control concentrations of soluble Se.

  11. Data for ground-water test hole near Butte City, Central Valley aquifer project, California

    USGS Publications Warehouse

    French, James J.; Page, R.W.; Bertoldi, G.L.

    1983-01-01

    This report provides preliminary data for the third of seven test holes drilled as part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 32, T. 19 N., R. 1 W., Glenn County, California, about one-half mile south of the town of Butte City. Drilled to a depth of 1,432 feet below land surface, the hole is cased to a depth of 82 feet and equipped with three piezometer tubes to depths of 592 feet, 968 feet, and 1,330 feet. A 5-foot well screen is at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer , and the well bore is filled between the plugs with sediment. Nine cores and 49 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, and chemical quality of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

  12. Data for ground-water test hole near Nicolaus, Central Valley aquifer project, California

    USGS Publications Warehouse

    French, James J.; Page, R.W.; Bertoldi, Gilbert L.

    1983-01-01

    Preliminary data are provided for the third of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 2, T.12N., R.3E., Sutter County, California, about 1 1/2 miles northwest of the town of Nicolaus. Drilled to a depth of 1,150 feet below land surface, the hole is cased to a depth of 100 feet and equipped with three piezometer tubes to depths of 311, 711, and 1,071 feet. A 5-foot well screen is set in sand at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer, and the well bore is filled between the plugs with sediment. Thirty-one cores and 34 sidewall cores were recovered. Laboratory tests were made for minerology, consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis of the three tapped zones and measured for water level. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

  13. Data for ground-water test hole near Zamora, Central Valley Aquifer Project, California

    USGS Publications Warehouse

    French, J.J.; Page, R.W.; Bertoldi, G.L.

    1982-01-01

    Preliminary data are presented for the first of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 SE 1/4 sec. 34, T. 12 N. , R. 1 E., Yolo County, California, about 3 miles northeast of the town of Zamora. Drilled to a depth of 2,500 feet below land surface, the hole is cased to a depth of 190 feet and equipped with three piezometer tubes to depths of 947, 1,401, and 2,125 feet. A 5-foot well screen is at the bottom of each piezometer. Eighteen cores and 68 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, diatom identification, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

  14. Comparison of Summer and Winter California Central Valley Aerosol Distributions from Lidar and MODIS Measurements

    NASA Technical Reports Server (NTRS)

    Lewis, Jasper; DeYoung, Russell; Ferrare, Richard; Chu, D. Allen

    2010-01-01

    Aerosol distributions from two aircraft lidar campaigns conducted in the California Central Valley are compared in order to identify seasonal variations. Aircraft lidar flights were conducted in June 2003 and February 2007. While the ground PM(sub 2.5) concentration is highest in the winter, the aerosol optical depth measured from MODIS is highest in the summer. A seasonal comparison shows that PM(sub 2.5) in the winter can exceed summer PM(sub 2.5) by 55%, while summer AOD exceeds winter AOD by 43%. Higher temperatures and wildfires in the summer produce elevated aerosol layers that are detected by satellite measurements, but not surface particulate matter monitors. Temperature inversions, especially during the winter, contribute to higher PM(sub 2.5) measurements at the surface. Measurements of the boundary layer height from lidar instruments provide valuable information need to understand the relationship between satellite measurements of optical depth and in-situ measurements of PM(sub 2.5).

  15. Height changes along selected lines through the Death Valley region, California and Nevada, 1905-1984

    USGS Publications Warehouse

    Castle, Robert O.; Gilmore, Thomas D.; Walker, James P.; Castle, Susan A.

    2005-01-01

    Comparisons among repeated levelings along selected lines through the Death Valley region of California and adjacent parts of Nevada have disclosed surprisingly large vertical displacements. The vertical control data in this lightly populated area is sparse; moreover, as much as a third of the recovered data is so thoroughly contaminated by systematic error and survey blunders that no attempt was made to correct these data and they were simply discarded. In spite of these limitations, generally episodic, commonly large vertical displacements are disclosed along a number of lines. Displacements in excess of 0.4 m, with respect to our selected control point at Beatty, Nevada, and differential displacements of about 0.7 m apparently occurred during the earlier years of the 20th century and continued episodically through at least 1943. While this area contains abundant evidence of continuing tectonic activity through latest Quaternary time, it is virtually devoid of historic seismicity. We have detected no clear connection between the described vertical displacements and fault zones reportedly active during Holocene time, although we sense some association with several more broadly defined tectonic features.

  16. High Resolution Monitoring of Algal Growth Dynamics in a Hypereutrophic River in the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Henson, S. S.; Dahlgren, R.; van Nieuwenhuyse, E.; O'Geen, A. T.; Gallo, E. L.; Ahearn, D. S.

    2005-05-01

    The lower San Joaquin River in California's Central Valley experiences periods of hypoxia during the late summer and fall that is detrimental to aquatic organisms and migration of fall-run chinook salmon and steelhead trout. Hypoxia is attributable, in part, to excess nutrients from urban waste water and agricultural runoff, which contribute to growth of high concentrations of phytoplankton. This study examined spatial and temporal growth patterns that control algal loading using continuous fluorescence measurements at three sites along a 50 km section of the lower San Joaquin River between April and October. A strong diel fluorescence signal was observed and associated grab samples verified that fluorescence was an accurate measure of chlorophyll. Peak chlorophyll concentrations occurred between 18:00 and 20:00 and minimum concentrations between 10:00 and 12:00. Maximum concentrations were nearly two times greater than minimum concentrations although this ratio varied temporally and spatially. Although the mechanism for the diel chlorophyll signal is not very well understood several parameters including temperature, irradiance, turbidity, residence time, stream depth, and zooplankton grazing were considered within the scope of this study. This study highlights the importance of considering high resolution sampling on algal loading rates within heavily impacted riverine systems.

  17. Groundwater flow and solute movement to drain laterals, western San Joaquin Valley, California: 1. Geochemical assessment

    USGS Publications Warehouse

    Deverel, S.J.; Fio, John L.

    1991-01-01

    A study was undertaken to quantitatively evaluate the hydrologic processes affecting the chemical and isotopic composition of drain lateral water in a drained agricultural field in the western San Joaquin Valley, California. The results elucidate the process of mixing of deep and shallow groundwater (below and within 6 m from land surface) entering the drain laterals. The deep groundwater was subject to evapoconcentration prior to drainage system installation and has been displaced downward (to depths greater than 6 m) in the groundwater system. The proportions of deep and shallow groundwater entering the drain laterals was calculated from the end-member oxygen 18 compositions determined in groundwater samples. The percentage of total drain lateral flow which is deep groundwater flow is about 30% for the shallow drain lateral (1.8 m below land surface) (drain lateral 1)) and 60% for the deep drain lateral (2.7 m below land surface (drain lateral 2)). During irrigation, the percentages of deep groundwater flow decrease to 0 and 30% for the shallow and deep drain laterals, respectively. Selenium concentrations in drain lateral waters decrease during irrigation but selenium loads increase. Total estimated annual loads were 1.1 and 5.4 kg of selenium for drain laterals 1 and 2, respectively. Substantial percentages of the annual load occurred during 8 days of irrigation, 23 and 9% for drain laterals 1 and 2, respectively.

  18. Economic potential and optimum steamflood strategies for trough reservoirs of San Joaquin Valley, California

    SciTech Connect

    Hong, K.C.; Use, D.J.

    1995-12-31

    Many trough reservoirs in the Western San Joaquin Valley, California, remain undeveloped because reserve bases are relatively small and occur in areas where thermal recovery activities have been low. Reservoir models with different configurations and reserve bases were used to compare the economic potential of these reservoirs and to develop guidelines for selecting reservoirs that can be economically exploited. The models were also used for determining the optimum steamflood strategies for the selected reservoirs. The study showed that, for a trough reservoir to be an economical prospect, it should contain a minimum oil-in-place of 300 MSTB per pattern length along the trough between the synclinal axis and the gas-oil contact. Optimum steamflood strategy for such reservoirs includes: (1) placing the injector away from the synclinal axis and gas-oil contact, (2) having a row of producers updip from the injector and another near the synclinal axis, (3) starting the steamflood with an intermediate rate and high quality of steam, and (4) shutting-in steam injection after 5.5 years of continuous injection at a constant rate. This strategy can result in an annual rate of return of 20%.

  19. Central California Valley Ecoregion: Chapter 17 in Status and trends of land change in the Western United States--1973 to 2000

    USGS Publications Warehouse

    Sleeter, Benjamin M.

    2012-01-01

    The Central California Valley Ecoregion, which covers approximately 45,983 km2 (17,754 mi2), is an elongated basin extending approximately 650 km north to south through central California (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is surrounded entirely by the Southern and Central California Chaparral and Oak Woodlands Ecoregion, which includes parts of the Coast Ranges to the west and which is bounded by the Sierra Nevada to the east. The Central California Valley Ecoregion accounts for more than half of California’s agricultural production value and is one of the most important agricultural regions in the country, with flat terrain, fertile soils, a favorable climate, and nearly 70 percent of its land in cultivation (Kuminoff and others, 2000; Sumner and others, 2003). Commodities produced in the region include milk and dairy, cattle and calves, cotton, almonds, citrus, and grapes, among others (U.S. Department of Agriculture, 2004; Johnston and McCalla, 2004; Kuminoff and others, 2000) (figs. 2A,B,C). Six of the top eight agricultural-producing counties in California are located at least partly within the Central California Valley Ecoregion (Kuminoff and others, 2000) (table 1). The Central California Valley Ecoregion is also home to nearly 5 million people spread throughout the region, including the major cities of Sacramento (state capital), Fresno, Bakersfield, and Stockton, California (U.S. Census Bureau, 2000) (fig. 1).

  20. Water-Quality Data for Selected Stream Sites in Bridgeport Valley, Mono County, California, April 2000 to June 2003

    USGS Publications Warehouse

    Rockwell, Gerald L.; Honeywell, Paul D.

    2004-01-01

    The U.S. Geological Survey, in cooperation with the California Regional Water Quality Control Board, Lahonton Region, carried out a water-quality data collection program of selected streams in and near Bridgeport Valley, California, during April 2000 to June 2003. These data were collected to provide information used by the California Regional Water Quality Control Board to develop total maximum daily load standards. Field measurements of streamflow, barometric pressure, dissolved oxygen, pH, specific conductance, and water temperature were made at 15 sites located on 6 streams. Water samples were analyzed for nutrients, major ions, turbidity, fecal coliform, fecal streptococci, and suspended sediment. Field data, turbidity, nutrient, major ion, and sediment concentrations and fecal coliform and fecal streptococci densities are given in tables for each site. Field blank data are also presented in a table.

  1. Estimated ground-water discharge by evapotranspiration from Death Valley, California, 1997-2001

    USGS Publications Warehouse

    DeMeo, Guy A.; Laczniak, Randell J.; Boyd, Robert A.; Smith, J. LaRue; Nylund, Walter E.

    2003-01-01

    The U.S. Geological Survey, in cooperation with the National Park Service and Inyo County, Calif., collected field data from 1997 through 2001 to accurately estimate the amount of annual ground-water discharge by evapotranspiration (ET) from the floor of Death Valley, California. Multispectral satellite-imagery and National Wetlands Inventory data are used to delineate evaporative ground-water discharge areas on the Death Valley floor. These areas are divided into five general units where ground-water discharge from ET is considered to be significant. Based upon similarities in soil type, soil moisture, vegetation type, and vegetation density; the ET units are salt-encrusted playa (21,287 acres), bare-soil playa (75,922 acres), low-density vegetation (6,625 acres), moderate-density vegetation (5,019 acres), and high-density vegetation (1,522 acres). Annual ET was computed for ET units with micrometeorological data which were continuously measured at six instrumented sites. Total ET was determined at sites that were chosen for their soil- and vegetated-surface conditions, which include salt-encrusted playa (extensive salt encrustation) 0.17 feet per year, bare-soil playa (silt and salt encrustation) 0.21 feet per year, pickleweed (pickleweed plants, low-density vegetation) 0.60 feet per year, Eagle Borax (arrowweed plants and salt grass, moderate-density vegetation) 1.99 feet per year, Mesquite Flat (mesquite trees, high-density vegetation) 2.86 feet per year, and Mesquite Flat mixed grasses (mixed meadow grasses, high-density vegetation) 3.90 feet per year. Precipitation, flooding, and ground-water discharge satisfy ET demand in Death Valley. Ground-water discharge is estimated by deducting local precipitation and flooding from cumulative ET estimates. Discharge rates from ET units were not estimated directly because the range of vegetation units far exceeded the five specific vegetation units that were measured. The rate of annual ground-water discharge by ET for

  2. Geomorphology and Tectonics at the Intersection of Silurian and Death Valleys, Southern California - 2005 Guidebook Pacific Cell Friends of the Pleistocene

    USGS Publications Warehouse

    Miller, David M.; Valin, Zenon C.

    2007-01-01

    This publication describes results from new regional and detailed surficial geologic mapping, combined with geomorphologic, geochronologic, and tectonic studies, in Silurian Valley and Death Valley, California. The studies address a long-standing problem, the tectonic and geomorphic evolution of the intersection between three regional tectonic provinces: the eastern California shear zone, the Basin and Range region of southern Nevada and adjacent California, and the eastern Mojave Desert region. The chapters represent work presented on the 2005 Friends of the Pleistocene field trip and meeting as well as the field trip road log.

  3. Comparison of Oxygenate Mixing Ratios Observed in the San Joaquin Valley, California, as a Consequence of Dairy Farming

    NASA Astrophysics Data System (ADS)

    Yang, M. M.; Blake, D. R.

    2009-12-01

    The San Joaquin Valley Air Basin in Central California is plagued with air quality problems, and is classified by the U.S. Environmental Protection Agency (EPA) as a serious non-attainment area for health-based eight-hour federal ozone (smog) standard (1). One of the main sources of Volatile Organic Compounds (VOCs), and indirect sources of ozone in the Valley, has been identified as dairy farming (2). Among these compounds, we have found that several OVOCs such as ethanol, methanol, acetone and acetaldehyde are produced in major quantities throughout the San Joaquin valley as by-products of yeast fermentation of silage and photochemical oxidation. These oxygenates, especially ethanol, play an important role in ozone (O3) formation within the valley. Since 2008, several different types of sampling protocols have been employed by our group in order to determine the degree of enhancement of the four oxygenates in the valley air shed, as well as to determine their sources, emission profiles and emission rates (2). In 2008 and 2009, samples were in early summer, allowing us to compare the difference in concentration levels between both years.The photochemical production of ozone was calculated for each of the four oxygenates and approximately one hundred other quantified VOCs. Based on the Maximum Incremental Reactivity (MIR) scale and concentrations of each oxygenate in the atmosphere, for both 2008 and 2009, as much as 15% of O3 production in the valley is from ethanol and its photochemical by-product acetaldehyde. Our findings suggest that the data observed in 2008 is consistent with that observed in 2009, with a slight decrease in concentrations overall for 2009. 1. Lindberg, J. Analysis of the San Joaquin Valley 2007 Ozone Plan. State of California Air Resources Board. Final Draft Staff Report. 5/30/2007. 2. M. Yang, S. Meinardi, C. Krauter, D.R. Blake. Characterization of VOC Emissions from Various Components of Dairy Farming and their effect on San Joaquin

  4. 77 FR 12527 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-01

    ... Management District and San Joaquin Valley Unified Air Pollution Control District AGENCY: Environmental... Antelope Valley Air Quality Management District (AVAQMD) and San Joaquin Valley Unified Air Pollution... Hawthorne Street, San Francisco, CA 94105-3901. Instructions: All comments will be included in the...

  5. Geologic evaluation of remote sensing data, site 157, Awza-Borrego Desert, California

    NASA Technical Reports Server (NTRS)

    Wolfe, E. W.

    1969-01-01

    Remote sensing data were obtained at site 157 in May 1968 under mission 73 of the NASA aircraft program. The site is located in an area of high temperatures and extreme aridity immediately west of the Imperial Valley, Southern California. Site 157 is partially surrounded by pre-Cenozoic crystalline rocks exposed in the Fish Creek, Vallecito, and Tierra Blanca Mountains. The study area itself is underlain by more than 20,000 feet of sedimentary strata of late Cenozoic age.

  6. A statistical learning framework for groundwater nitrate models of the Central Valley, California, USA

    NASA Astrophysics Data System (ADS)

    Nolan, Bernard T.; Fienen, Michael N.; Lorenz, David L.

    2015-12-01

    We used a statistical learning framework to evaluate the ability of three machine-learning methods to predict nitrate concentration in shallow groundwater of the Central Valley, California: boosted regression trees (BRT), artificial neural networks (ANN), and Bayesian networks (BN). Machine learning methods can learn complex patterns in the data but because of overfitting may not generalize well to new data. The statistical learning framework involves cross-validation (CV) training and testing data and a separate hold-out data set for model evaluation, with the goal of optimizing predictive performance by controlling for model overfit. The order of prediction performance according to both CV testing R2 and that for the hold-out data set was BRT > BN > ANN. For each method we identified two models based on CV testing results: that with maximum testing R2 and a version with R2 within one standard error of the maximum (the 1SE model). The former yielded CV training R2 values of 0.94-1.0. Cross-validation testing R2 values indicate predictive performance, and these were 0.22-0.39 for the maximum R2 models and 0.19-0.36 for the 1SE models. Evaluation with hold-out data suggested that the 1SE BRT and ANN models predicted better for an independent data set compared with the maximum R2 versions, which is relevant to extrapolation by mapping. Scatterplots of predicted vs. observed hold-out data obtained for final models helped identify prediction bias, which was fairly pronounced for ANN and BN. Lastly, the models were compared with multiple linear regression (MLR) and a previous random forest regression (RFR) model. Whereas BRT results were comparable to RFR, MLR had low hold-out R2 (0.07) and explained less than half the variation in the training data. Spatial patterns of predictions by the final, 1SE BRT model agreed reasonably well with previously observed patterns of nitrate occurrence in groundwater of the Central Valley.

  7. The Significance of Wellbore Flow in the Santa Clara Valley, California

    NASA Astrophysics Data System (ADS)

    Hanson, R. T.

    2005-12-01

    Interaquifer flow through water-supply wells screened across multiple aquifers is an important component to the flow of ground water in many developed aquifer systems. Wellbore flow in the Santa Clara Valley, California, was examined using flow measurements, hydrochemistry, and numerical simulations. Interaquifer flow was assessed locally using a combination of wellbore flow measurements and depth-dependent water-chemistry sampling at three water-supply wells and depth-specific samples from multiple-well monitoring sites. Interaquifer flow owing to wellbore flow in hundreds of multi-aquifer supply wells was assessed regionally using a simulation model of regional ground-water flow. Wellbore flow and depth-dependent chemical and isotopic data indicate that flow into the well from multiple aquifers, as well as capture of artificial recharge by pumping of water-supply wells, predominantly is occurring in the upper 500 feet of the aquifer system. Uncorrected carbon-14 data indicates that the ground water in the upper 500 feet generally is less than 2,000 years old, and ground water in the deeper aquifer layers generally ranges from 16,700 to 39,900 years old. Results of depth-dependent and depth-specific sampling collectively suggest that wellbores may be the main path for vertical flow between aquifer layers. In addition, on the west side of the valley, the ground water in the shallower aquifers (< 500 ft depth) contains a substantial amount of water from artificial recharge. Deuterium and oxygen isotopic data indicate as much as 60 percent of water pumped from production wells in this area originated as artificial recharge. Depth-dependent samples from water-supply wells also helped to better delineate trace amounts of anthropogenic contaminants coming from shallower aquifers . In addition to wellbore measurements, the regional effects of wellbore flow were assessed with a regional ground-water flow model that included the simulation of wellbore flow from wells

  8. Radon Outgassing in the Casa Diablo Region, Long Valley Caldera, California

    NASA Astrophysics Data System (ADS)

    Adarkwah, N.; Cuff, K.

    2003-12-01

    A radon outgassing survey has been conducted in the Casa Diablo region of the Long Valley Caldera. The Long Valley Caldera (LVC) is an active volcanic system situated along the eastern front of the Sierra Nevada mountain range in east-central California. The survey was centered in an area .4 km northwest of the Casa Diablo geothermal power plant, located along the southwestern-most rim of the caldera?s resurgent dome. Results from previous radon emission studies in LVC indicate that high degrees of outgassing occur in association with relatively narrow networks of unsealed fractures (Cuff, et al., 2000 and Hoyos, et al., 2001). These fracture networks act as pathways for radon and other gases generated at depth as they migrate toward the surface. The purpose of the present study was to determine whether or not a relationship exists between radon emissions in the current survey area and that in a previously surveyed area approximately .8 km west of the geothermal plant. To accomplish this, we measured radon concentration in soil-gas at 35 separate sites. These sites were located within a 140 by 100 meter grid, with 20 meter spacing between each sample site. A radon outgassing map was then created using measured concentration values along with longitude and latitude values for each sample location. Geologic maps of the area were also analyzed and compared with radon outgassing maps. Analysis of these maps indicates that radon outgassing occurs through a set of crisscrossing fractures, trending southwest-northeast and northwest-southeast respectively. The northwest trending fractures are related to mapped normal faults in the area, while those with a southwest-northeast orientation are associated with an unmapped zone of faulting that is roughly perpendicular to the other faults. The latter set of fractures has a trend similar to that discovered in the previously surveyed area to the west. In both areas the highest readings were in excess of three times background

  9. Continuous monitoring of surface deformation at Long Valley Caldera, California, with GPS

    USGS Publications Warehouse

    Dixon, T.H.; Mao, A.; Bursik, M.; Heflin, M.; Langbein, J.; Stein, R.; Webb, F.

    1997-01-01

    Continuous Global Positioning System (GPS) measurements at Long Valley Caldera, an active volcanic region in east central California, have been made on the south side of the resurgent dome since early 1993. A site on the north side of the dome was added in late 1994. Special adaptations for autonomous operation in remote regions and enhanced vertical precision were made. The data record ongoing volcanic deformation consistent with uplift and expansion of the surface above a shallow magma chamber. Measurement precisions (1 standard error) for "absolute" position coordinates, i.e., relative to a global reference frame, are 3-4 mm (north), 5-6 mm (east), and 10-12 mm (vertical) using 24 hour solutions. Corresponding velocity uncertainties for a 12 month period are about 2 mm/yr in the horizontal components and 3-4 mm/yr in the vertical component. High precision can also be achieved for relative position coordinates on short (<10 km) baselines using broadcast ephemerides and observing times as short as 3 hours, even when data are processed rapidly on site. Comparison of baseline length changes across the resurgent dome between the two GPS sites and corresponding two-color electronic distance measurements indicates similar extension rates within error (???2 mm/yr) once we account for a random walk noise component in both systems that may reflect spurious monument motion. Both data sets suggest a pause in deformation for a 3.5 month period in mid-1995, when the extension rate across the dome decreased essentially to zero. Three dimensional positioning data from the two GPS stations suggest a depth (5.8??1.6 km) and location (west side of the resurgent dome) of a major inflation center, in agreement with other geodetic techniques, near the top of a magma chamber inferred from seismic data. GPS systems similar to those installed at Long Valley can provide a practical method for near real-time monitoring and hazard assessment on many active volcanoes.

  10. A statistical learning framework for groundwater nitrate models of the Central Valley, California, USA

    USGS Publications Warehouse

    Nolan, Bernard T.; Fienen, Michael N.; Lorenz, David L.

    2015-01-01

    We used a statistical learning framework to evaluate the ability of three machine-learning methods to predict nitrate concentration in shallow groundwater of the Central Valley, California: boosted regression trees (BRT), artificial neural networks (ANN), and Bayesian networks (BN). Machine learning methods can learn complex patterns in the data but because of overfitting may not generalize well to new data. The statistical learning framework involves cross-validation (CV) training and testing data and a separate hold-out data set for model evaluation, with the goal of optimizing predictive performance by controlling for model overfit. The order of prediction performance according to both CV testing R2 and that for the hold-out data set was BRT > BN > ANN. For each method we identified two models based on CV testing results: that with maximum testing R2 and a version with R2 within one standard error of the maximum (the 1SE model). The former yielded CV training R2 values of 0.94–1.0. Cross-validation testing R2 values indicate predictive performance, and these were 0.22–0.39 for the maximum R2 models and 0.19–0.36 for the 1SE models. Evaluation with hold-out data suggested that the 1SE BRT and ANN models predicted better for an independent data set compared with the maximum R2 versions, which is relevant to extrapolation by mapping. Scatterplots of predicted vs. observed hold-out data obtained for final models helped identify prediction bias, which was fairly pronounced for ANN and BN. Lastly, the models were compared with multiple linear regression (MLR) and a previous random forest regression (RFR) model. Whereas BRT results were comparable to RFR, MLR had low hold-out R2 (0.07) and explained less than half the variation in the training data. Spatial patterns of predictions by the final, 1SE BRT model agreed reasonably well with previously observed patterns of nitrate occurrence in groundwater of the Central Valley.

  11. Analog model study of the ground-water basin of the Upper Coachella Valley, California

    USGS Publications Warehouse

    Tyley, Stephen J.

    1974-01-01

    An analog model of the ground-water basin of the upper Coachella Valley was constructed to determine the effects of imported water on ground-water levels. The model was considered verified when the ground-water levels generated by the model approximated the historical change in water levels of the ground-water basin caused by man's activities for the period 1986-67. The ground-water basin was almost unaffected by man's activities until about 1945 when ground-water development caused the water levels to begin to decline. The Palm Springs area has had the largest water-level decline, 75 feet since 1986, because of large pumpage, reduced natural inflow from the San Gorgonio Pass area, and diversions of natural inflows at Snow and Falls Creeks and Chino Canyon starting in 1945. The San Gorgonio Pass inflow had been reduced from about 18,000 acre-feet in 1986 to about 9,000 acre-feet by 1967 because of increased ground-water pumpage in the San Gorgonio Pass area, dewatering of the San Gorgonio Pass area that took place when the tunnel for the Metropolitan Water District of Southern California was drilled, and diversions of surface inflow at Snow and Falls Creeks. In addition, 1944-64 was a period of below-normal precipitation which, in part, contributed to the declines in water levels in the Coachella Valley. The Desert Hot Springs, Garnet Hill, and Mission Creek subbasins have had relatively little development; consequently, the water-level declines have been small, ranging from 5 to 15 feet since 1986. In the Point Happy area a decline of about 2 feet per year continued until 1949 when delivery of Colorado River water to the lower valley through the Coachella Canal was initiated. Since 1949 the water levels in the Point Happy area have been rising and by 1967 were above their 1986 levels. The Whitewater River subbasin includes the largest aquifer in the basin, having sustained ground-water pumpage of about 740,000 acre-feet from 1986 to 1967, and will probably

  12. Seroprevalence of Hepatitis B and C Infections among Healthy Volunteer Blood Donors in the Central California Valley

    PubMed Central

    Atla, Pradeep R.; Ameer, Adnan; Sadiq, Humaira; Sadler, Patrick C.

    2013-01-01

    Background/Aims The Central California Valley has a diverse population with significant proportions of Hispanics and Asians. This cross-sectional study was conducted to evaluate the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in healthy blood donors in the Valley. Methods A total of 217,738 voluntary blood donors were identified between 2006 and 2010 (36,795 first-time donors; 180,943 repeat donors). Results Among the first-time donors, the HBV and HCV prevalence was 0.28% and 0.52%, respectively. Higher HBV prevalence seen in Asians (3%) followed by Caucasians (0.05%), African Americans (0.15%), and Hispanics (0.05%). Hmong had a HBV prevalence of 7.63% with a peak prevalence of 8.76% among the 16- to 35-year-old age group. Highest HCV prevalence in Native Americans (2.8) followed by Caucasians (0.59%), Hispanics (0.45%), African Americans (0.38%), and Asians (0.2%). Conclusions Ethnic disparities persist with regard to the prevalence of HBV and HCV in the Central California Valley. The reported prevalence may be an underestimate because our study enrolled healthy volunteer blood donors only. The development of aggressive public health measures to evaluate the true prevalence of HBV and HCV and to identify those in need of HBV and HCV prevention measures and therapy is critically important. PMID:23423771

  13. Field Trial of Distributed Acoustic Sensing Using Active Sources at Garner Valley, California

    NASA Astrophysics Data System (ADS)

    Wang, H. F.; Lord, N. E.; Chalari, A.; Lancelle, C.; Baldwin, J. A.; Castongia, E.; Fratta, D.; Nigbor, R. L.; Karaulanov, R.

    2014-12-01

    An optical fiber Distributed Acoustic Sensor array was deployed in a shallow trench at the site of the Garner Valley Downhole Array (GVDA) in southern California. The site was operated as a collaborator of the Network for Earthquake Engineering Simulation (NEES) by UCSB. The fiber-optic cable layout approximated a rectangle whose dimensions were roughly 160 meters by 80 meters. The layout included two subdiagonals to provide a variety of orientations of the cable relative to source locations. The study included different seismic sources deployed at a number of surveyed positions: a 45 kN shear shaker operated at the site by NEES@UCLA, a portable 450 N shaker, a small Vibroseis truck, and hammer blows on a steel plate to map cable locations. Several dozen separate tests were recorded in which each test typically included ten repeats. The data were utilized for several studies. First, the characteristics of the recorded signals were analyzed for directivity and sensitivity of the cable response (Lancelle et al., 2014, this meeting). The DAS system recorded dynamic ground events in the direction of the cable and hence comparisons with geophones required signal processing. The one-meter spacing of DAS traces could be well correlated over distances of a few meters. Second, swept-sine sources were used to obtain surface-wave velocity dispersion to determine near-surface shear-wave velocity distribution using Multispectral Analysis of Surface Waves (MASW) (Baldwin et al., 2014, this meeting). The results were in good agreement with previous Vibroseis results at the site (Stokoe et al. 2004). Third, a new method for time-frequency filtering was developed for extracting the surface-wave phase velocities from uncorrelated receiver traces (Lord et al., 2014, this meeting).

  14. Geological mapping of the vertical southeast face of El Capitan, Yosemite Valley, California (Invited)

    NASA Astrophysics Data System (ADS)

    Stock, G. M.; Glazner, A. F.; Ratajeski, K.; Law, B.

    2010-12-01

    El Capitan in Yosemite Valley, California, is one of the world’s most accessible large granitic rock faces. At nearly 1 km tall, the vertical southeast face of El Capitan provides unique insight into igneous processes contributing to the assembly of the Sierra Nevada batholith ~103 million years ago. Although the base and summit dome of El Capitan have been mapped in detail, the vertical face has so far eluded comprehensive attempts at geologic mapping. We have combined field mapping by technical rock climbing with high-resolution gigapixel photography to develop the first detailed digital geologic map of the southeast face (North America Wall). Geologic units exposed on the face include the El Capitan and Taft Granites, at least two phases of dioritic intrusions, hybridized rocks, and late-stage aplite/pegmatite dikes and pods. We map these units on a high resolution far-range base image derived from a high-resolution panoramic photograph, and verify contact relationships with close-range field photographs and visual observations from anchor points along major climbing routes. Mapping of contact relationships between these units reveals the sequence of intrusion of the various units, as well as the relationship of the mafic intrusions with the more voluminous granites. Geologic mapping of the southeast face also informs geologic hazards by constraining the source area for lithologically distinct rock falls; for example, geologic mapping confirms that a 2.2 x 106 m3 rock avalanche that occurred circa 3,600 years ago originated from near the summit of El Capitan, within an area dominated by Taft Granite. In addition to expanding mapping to the southwest face, future mapping efforts will focus on integrating the high resolution base map with airborne and terrestrial LiDAR data to produce a three-dimensional geologic map of one of the most iconic rock formations in the world.

  15. Using Airborne Laser Altimetry to Detect Topographic Change at Long Valley Caldera California

    NASA Technical Reports Server (NTRS)

    Hofton, M. A.; Minster, J.-B.; Ridgway, J. R.; Williams, N. P.; Blair, J. B.; Rabine, D. L.; Bufton, J. L.

    2000-01-01

    The topography of the Long Valley caldera, California, was sampled using airborne laser altimetry in 1993, 1995, and 1997 to test the feasibility of using airborne laser altimetry for monitoring deformation of volcanic origin. Results show the laser altimeters are able to resolve subtle topographic features such as a gradual slope and to detect small transient changes in lake elevation. Crossover and repeat pass analyses of laser tracks indicate decimeter-level vertical precision is obtained over flat and low-sloped terrain for altimeter systems performing waveform digitization. Comparisons with complementary, ground-based CPS data at a site close to Bishop airport indicate that the laser and GPS-derived elevations agree to within the error inherent in the measurement and that horizontal locations agree to within the radius of the laser footprint. A comparison of the data at two sites, one where no change and the other where the maximum amount of vertical uplift is expected, indicates approximately 10 cm of relative uplift occurred 1993-1997, in line with predictions from continuous CPS measurements in the region. Extensive terrain mapping flights during the 1995 and 1997 missions demonstrate some of the unique abilities of laser altimetry; the straightforward creation of high resolution, high accuracy digital elevation models of overflown terrain, and the ability to determine ground topography in the presence of significant ground cover such as dense tree canopies. These capabilities make laser altimetry an attractive technique for quantifying topographic change of volcanic origin, especially in forested regions of the world where other remote sensing instruments have difficulty detecting the underlying topography.

  16. Using Airborne Laser Altimetry to Detect Topographic Change at Long Valley Caldera, California

    NASA Technical Reports Server (NTRS)

    Hofton, M. A.; Minster, J.-B.; Ridgway, J. R.; Williams, N. P.; Blair, J.-B.; Rabine, D. L.; Bufton, J. L.

    1999-01-01

    The topography of the Long Valley caldera, California, was sampled using airborne laser altimetry in 1993, 1995, and 1997 to test the feasibility of using airborne laser altimetry for monitoring deformation of volcanic origin. Results show the laser altimeters are able to resolve subtle topographic features such as a gradual slope and to detect small transient changes in lake elevation. Crossover and repeat pass analyses of laser tracks indicate decimeter-level vertical precision is obtained over flat and low-sloped terrain for altimeter systems performing waveform digitization. Comparisons with complementary, ground-based GPS data at a site close to Bishop airport indicate that the laser and GPS-derived elevations agree to within the error inherent in the measurement and that horizontal locations agree to within the radius of the laser footprint. A comparison of the data at two sites, one where no change and the other where the maximum amount of vertical uplift is expected, indicates approximately 10 cm of relative uplift occurred 1993-1997, in line with predictions from continuous GPS measurements in the region. Extensive terrain mapping flights during the 1995 and 1997 missions demonstrate some of the unique abilities of laser altimetry; the straightforward creation of high resolution, high accuracy digital elevation models of overflown terrain, and the ability to determine ground topography in the presence of significant ground cover such as dense tree canopies. These capabilities make laser altimetry an attractive technique for quantifying topographic change of volcanic origin, especially in forested regions of the world where other remote sensing instruments have difficulty detecting the underlying topography.

  17. Hydrothermal contamination of public supply wells in Napa and Sonoma Valleys, California

    USGS Publications Warehouse

    Forrest, Matthew J.; Kulongoski, Justin T.; Edwards, Matthew S.; Farrar, Christopher D.; Belitz, Kenneth; Norris, Richard D.

    2013-01-01

    Groundwater chemistry and isotope data from 44 public supply wells in the Napa and Sonoma Valleys, California were determined to investigate mixing of relatively shallow groundwater with deeper hydrothermal fluids. Multivariate analyses including Cluster Analyses, Multidimensional Scaling (MDS), Principal Components Analyses (PCA), Analysis of Similarities (ANOSIM), and Similarity Percentage Analyses (SIMPER) were used to elucidate constituent distribution patterns, determine which constituents are significantly associated with these hydrothermal systems, and investigate hydrothermal contamination of local groundwater used for drinking water. Multivariate statistical analyses were essential to this study because traditional methods, such as mixing tests involving single species (e.g. Cl or SiO2) were incapable of quantifying component proportions due to mixing of multiple water types. Based on these analyses, water samples collected from the wells were broadly classified as fresh groundwater, saline waters, hydrothermal fluids, or mixed hydrothermal fluids/meteoric water wells. The Multivariate Mixing and Mass-balance (M3) model was applied in order to determine the proportion of hydrothermal fluids, saline water, and fresh groundwater in each sample. Major ions, isotopes, and physical parameters of the waters were used to characterize the hydrothermal fluids as Na–Cl type, with significant enrichment in the trace elements As, B, F and Li. Five of the wells from this study were classified as hydrothermal, 28 as fresh groundwater, two as saline water, and nine as mixed hydrothermal fluids/meteoric water wells. The M3 mixing-model results indicated that the nine mixed wells contained between 14% and 30% hydrothermal fluids. Further, the chemical analyses show that several of these mixed-water wells have concentrations of As, F and B that exceed drinking-water standards or notification levels due to contamination by hydrothermal fluids.

  18. Modeling Land Application of Food-Processing Wastewater in the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Rubin, Y.; Benito, P.; Miller, G.; McLaughlin, J.; Hou, Z.; Hermanowicz, S.; Mayer, U.

    2007-12-01

    California's Central Valley contains over 640 food-processing plants, serving a multi-billion dollar agricultural industry. These processors consume approximately 7.9 x 107 m3 of water per year. Approximately 80% of these processors discharge the resulting wastewater, which is typically high in organic matter, nitrogen, and salts, to land, and many of these use land application as a treatment method. Initial investigations revealed elevated salinity levels to be the most common form of groundwater degradation near land application sites, followed by concentrations of nitrogen compounds, namely ammonia and nitrate. Enforcement actions have been taken against multiple food processors, and the regulatory boards have begun to re-examine the land disposal permitting process. This paper summarizes a study that was commissioned in support of these actions. The study has multiple components which will be reviewed briefly, including: (1) characterization of the food-processing related waste stream; (2) fate and transport of the effluent waste stream in the unsaturated zone at the land application sites; (3) fate and transport of the effluent waste stream at the regional scale; (4) predictive uncertainty due to spatial variability and data scarcity at the land application sites and at the regional scale; (5) problem mitigation through off-site and in-situ actions; (6) long-term solutions. The emphasis of the talk will be placed on presenting and demonstrating a stochastic framework for modeling the transport and attenuation of these wastes in the vadose zone and in the saturated zone, and the related site characterization needs, as affected by site conditions, water table depth, waste water application rate, and waste constituent concentrations.

  19. Regional nitrate and pesticide trends in ground water in the eastern San Joaquin Valley, California

    USGS Publications Warehouse

    Burow, K.R.; Shelton, James L.; Dubrovsky, N.M.

    2008-01-01

    Protection of ground water for present and future use requires monitoring and understanding of the mechanisms controlling long-term quality of ground water. In this study, spatial and temporal trends in concentrations of nitrate and pesticides in ground water in the eastern San Joaquin Valley, California, were evaluated to determine the long-term effects of agricultural and urban development on regional ground-water quality. Trends in concentrations of nitrate, the nematocide 1,2-dibromo-3-chloropropane, and the herbicide simazine during the last two decades are generally consistent with known nitrogen fertilizer and pesticide use and with the position of the well networks in the regional ground-water flow system. Concentrations of nitrate and pesticides are higher in the shallow part of the aquifer system where domestic wells are typically screened, whereas concentrations are lower in the deep part of the aquifer system where public-supply wells are typically screened. Attenuation processes do not seem to significantly affect concentrations. Historical data indicate that concentrations of nitrate have increased since the 1950s in the shallow and deep parts of the aquifer system. Concentrations of nitrate and detection of pesticides in the deep part of the aquifer system will likely increase as the proportion of highly affected water contributed to these wells increases with time. Because of the time of travel between the water table and the deep part of the aquifer system, current concentrations in public-supply wells likely reflect the effects of 40- to 50-yr-old management practices. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  20. Selenium and sulfur relationships in alfalfa and soil under field conditions, San Joaquin Valley, California

    USGS Publications Warehouse

    Severson, R.C.; Gough, L.P.

    1992-01-01

    Relationships between total Se and S or soluble SeO4 and SO4 in soils and tissue concentrations in alfalfa (Medicago sativa L.), under field conditions in the San Joaquin Valley of California, suggest that the rate of accumulation of Se in alfalfa may be reduced in areas where high Se and S concentrations in soils were measured. These data suggest that the balance between carbonate and sulfate minerals in soil may have a greater influence on uptake of Se by alfalfa than does the balance of SeO4 and SO4 in soil solution. Soil and alfalfa were sampled from areas representing a wide range in soil Se and S concentrations. Specific sampling locations were selected based on a previous study of Se, S, and other elements where 721 soil samples were collected to map landscape variability and distribution of elements. Six multiple-linear regression equations were developed between total and/or soluble soil chemical constituents and tissue concentrations of Se in alfalfa. We chose a regression model that accounted for 72% of the variability in alfalfa Se concentrations based on an association of elements in soil (total C, S, Se, and Sr) determined by factor analysis. To prepare a map showing the spatial distribution of estimated alfalfa Se concentrations, the model was applied to the data from the previously collected 721 soil samples. Estimated alfalfa Se concentrations in most of the study area were within a range that is predicted to produce alfalfa with neither Se deficiency nor toxicity when consumed by livestock. A few small areas are predicted to produce alfalfa that potentially would not meet minimum dietary needs of livestock.

  1. Bottom-up, decision support system development : a wetlandsalinity management application in California's San Joaquin Valley

    SciTech Connect

    Quinn, Nigel W.T.

    2006-05-10

    Seasonally managed wetlands in the Grasslands Basin ofCalifornia's San Joaquin Valley provide food and shelter for migratorywildfowl during winter months and sport for waterfowl hunters during theannual duck season. Surface water supply to these wetland contain saltwhich, when drained to the San Joaquin River during the annual drawdownperiod, negatively impacts downstream agricultural riparian waterdiverters. Recent environmental regulation, limiting discharges salinityto the San Joaquin River and primarily targeting agricultural non-pointsources, now addresses return flows from seasonally managed wetlands.Real-time water quality management has been advocated as a means ofmatching wetland return flows to the assimilative capacity of the SanJoaquin River. Past attempts to build environmental monitoring anddecision support systems to implement this concept have failed forreasons that are discussed in this paper. These reasons are discussed inthe context of more general challenges facing the successfulimplementation of environmental monitoring, modelling and decisionsupport systems. The paper then provides details of a current researchand development project which will ultimately provide wetland managerswith the means of matching salt exports with the available assimilativecapacity of the San Joaquin River, when fully implemented. Manipulationof the traditional wetland drawdown comes at a potential cost to thesustainability of optimal wetland moist soil plant habitat in thesewetlands - hence the project provides appropriate data and a feedback andresponse mechanism for wetland managers to balance improvements to SanJoaquin River quality with internally-generated information on the healthof the wetland resource. The author concludes the paper by arguing thatthe architecture of the current project decision support system, whencoupled with recent advances in environmental data acquisition, dataprocessing and information dissemination technology, holds significantpromise

  2. The 1998 earthquake sequence south of Long Valley Caldera, California: Hints of magmatic involvement

    USGS Publications Warehouse

    Hough, S.E.; Dollar, R.S.; Johnson, P.

    2000-01-01

    A significant episode of seismic and geodetic unrest took place at Long Valley Caldera, California, beginning in the summer of 1997. Activity through late May of 1998 was concentrated in and around the south moat and the south margin of the resurgent dome. The Sierran Nevada block (SNB) region to the south/southeast remained relatively quiet until a M 5.1 event occurred there on 9 June 1998 (UT). A second M 5.1 event followed on 15 July (UT); both events were followed by appreciable aftershock sequences. An additional, distinct burst of activity began on 1 August 1998. The number of events in the August sequence (over the first week or two) was similar to the aftershock sequence of the 15 July 1998 M 5.1 event, but the later sequence was not associated with any events larger than M 4.3. All of the summer 1998 SNB activity was considered tectonic rather than magmatic; in general the SNB is considered an unlikely location for future eruptions. However, the August sequence-an 'aftershock sequence without a mainshock'-is suggestive of a strain event larger than the cumulative seismotectonic strain release. Moreover, a careful examination of waveforms from the August sequence reveals a small handful of events whose spectral signature is strikingly harmonic. We investigate the waveforms of these events using spectral, autocorrelation, and empirical Green's function techniques and conclude that they were most likely associated with a fluid-controlled source. Our observations suggest that there may have been some degree of magma or magma-derived fluid involvement in the 1998 SNB sequence.

  3. Dissolved Pesticide and Organic Carbon Concentrations Detected in Surface Waters, Northern Central Valley, California, 2001-2002

    USGS Publications Warehouse

    Orlando, James L.; Jacobson, Lisa A.; Kuivila, Kathryn M.

    2004-01-01

    Field and laboratory studies were conducted to determine the effects of pesticide mixtures on Chinook salmon under various environmental conditions in surface waters of the northern Central Valley of California. This project was a collaborative effort between the U.S. Geological Survey (USGS) and the University of California. The project focused on understanding the environmental factors that influence the toxicity of pesticides to juvenile salmon and their prey. During the periods January through March 2001 and January through May 2002, water samples were collected at eight surface water sites in the northern Central Valley of California and analyzed by the USGS for dissolved pesticide and dissolved organic carbon concentrations. Water samples were also collected by the USGS at the same sites for aquatic toxicity testing by the Aquatic Toxicity Laboratory at the University of California Davis; however, presentation of the results of these toxicity tests is beyond the scope of this report. Samples were collected to characterize dissolved pesticide and dissolved organic carbon concentrations, and aquatic toxicity, associated with winter storm runoff concurrent with winter run Chinook salmon out-migration. Sites were selected that represented the primary habitat of juvenile Chinook salmon and included major tributaries within the Sacramento and San Joaquin River Basins and the Sacramento?San Joaquin Delta. Water samples were collected daily for a period of seven days during two winter storm events in each year. Additional samples were collected weekly during January through April or May in both years. Concentrations of 31 currently used pesticides were measured in filtered water samples using solid-phase extraction and gas chromatography-mass spectrometry at the U.S. Geological Survey's organic chemistry laboratory in Sacramento, California. Dissolved organic carbon concentrations were analyzed in filtered water samples using a Shimadzu TOC-5000A total organic carbon

  4. Dissolved phosphorus distribution in shallow groundwater beneath dairy farms, Central Valley, California

    NASA Astrophysics Data System (ADS)

    Young, M. B.; Lockhart, K.; Holstege, D.; Applegate, O.; Harter, T.

    2012-12-01

    Concentrated animal farming operations (CAFOs) often produce surface runoff with high phosphorus (P) concentrations, but much less is known about P leaching and distributions in shallow groundwater beneath CAFOs. In this study, concentrations of soluble P were measured in shallow groundwater beneath ten dairies located in the Central Valley, California between 1998 and 2009 to assess spatial and temporal variability in areas of higher and lower hydrogeological vulnerability to groundwater contamination, and to investigate both land uses and physiochemical parameters associated with soluble P distribution. Distribution of bioavailable soil phosphate (bicarbonate extraction) was also examined in soil cores from several of the dairies in order to asses potential links between P distribution in the vadose zone and dissolved P concentrations near the top of the groundwater table. Dissolved P and other geochemical constituents were measured in 200 domestic drinking water wells to examine differences in shallow and deeper groundwater within the region. Samples from dairies and domestic wells were collected from two distinct regions in the Central Valley. The northern region (northeastern San Joaquin Valley) is characterized by a shallower water table, sandy soils, and groundwater discharges to surface water, whereas the southern region (Tulare Lake Basin) is characterized by a much deeper water table and does not have natural discharges of groundwater to surface water. Mean dissolved P concentrations were highest in the two dairies with the shallowest water table and sandiest soils, although dissolved P concentrations were highly variable across monitoring wells within individual dairies. Dissolved P ranged from below detection (< 0.05 mg/L) up to 18.6 mg/L in the northern dairy monitoring wells, and from below detection up to 0.12 mg/L in the southern dairy monitoring wells. For the two dairies with tile drains, discharge from the drains was also sampled, and dissolved P

  5. High-resolution seismic reflection/refraction imaging from Interstate 10 to Cherry Valley Boulevard, Cherry Valley, Riverside County, California: implications for water resources and earthquake hazards

    USGS Publications Warehouse

    Gandhok, G.; Catchings, R.D.; Goldman, M.R.; Horta, E.; Rymer, M.J.; Martin, P.; Christensen, A.

    1999-01-01

    This report is the second of two reports on seismic imaging investigations conducted by the U.S. Geological Survey (USGS) during the summers of 1997 and 1998 in the Cherry Valley area in California (Figure 1a). In the first report (Catchings et al., 1999), data and interpretations were presented for four seismic imaging profiles (CV-1, CV-2, CV-3, and CV-4) acquired during the summer of 1997 . In this report, we present data and interpretations for three additional profiles (CV-5, CV-6, and CV-7) acquired during the summer of 1998 and the combined seismic images for all seven profiles. This report addresses both groundwater resources and earthquake hazards in the San Gorgonio Pass area because the shallow (upper few hundred meters) subsurface stratigraphy and structure affect both issues. The cities of Cherry Valley and Beaumont are located approximately 130 km (~80 miles) east of Los Angeles, California along the southern alluvial fan of the San Bernardino Mountains (see Figure 1b). These cities are two of several small cities that are located within San Gorgonio Pass, a lower-lying area between the San Bernardino and the San Jacinto Mountains. Cherry Valley and Beaumont are desert cities with summer daytime temperatures often well above 100 o F. High water usage in the arid climate taxes the available groundwater supply in the region, increasing the need for efficient management of the groundwater resources. The USGS and the San Gorgonio Water District (SGWD) work cooperatively to evaluate the quantity and quality of groundwater supply in the San Gorgonio Pass region. To better manage the water supplies within the District during wet and dry periods, the SGWD sought to develop a groundwater recharge program, whereby, excess water would be stored in underground aquifers during wet periods (principally winter months) and retrieved during dry periods (principally summer months). The SGWD preferred a surface recharge approach because it could be less expensive than a

  6. Ophiolitic basement to a forearc basin and implications for continental growth: The Coast Range/Great Valley ophiolite, California

    NASA Astrophysics Data System (ADS)

    Godfrey, Nicola J.; Klemperer, Simon L.

    1998-08-01

    We present a compilation of 18 published models from the length of the Great Valley forearc basin, California, based on seismic reflection, borehole, seismic refraction, gravity, and aeromagnetic data to address long-standing questions about the nature of the basement to the Great Valley, its origin, its tectonic history, and it's mechanism of incorporation into the North American continental margin. The geophysical models permit a 700-km-long, 70-km-wide, complete ophiolite sequence beneath the entire Great Valley. In the northern Great Valley, the ophiolite is overlain by ophiolitic breccia, the ophiolite crust is 7-8 km thick, and the mantle section is mostly unserpentinized. Beneath the southern Great Valley, there is no ophiolitic breccia, the crust may be up to 10 - 12 km thick, and the mantle section, if present at all, is serpentinized to such a degree that it cannot be distinguished from Sierran basement or mafic ophiolite members on the basis of velocity or density data. Geochemical, petrological, and paleomagnetic data support suprasubduction zone ophiolite formation at North American paleolatitudes, and geological data and geophysical models are consistent with ophiolite formation by back arc spreading behind an east facing arc. In the north, this was apparently followed by obduction of back arc crust onto older continental basement during the Late Jurassic Nevadan orogeny. In the south, the newly formed intraoceanic arc and back arc apparently collided with the continental margin during the Nevadan orogeny but were not obducted onto it. Instead, the arc and back arc "docked" with the continental margin leaving the arc itself to become the basement to the Great Valley basin. Cretaceous Sierran magmatism then intruded plutons beneath the docked ophiolite and mafic arc. Irrespective of the detailed accretionary history, our cross sections show a rapid pulse of continental growth by ophiolite accretion of more than 500 km³ km-1 in less than 10 Myr.

  7. Evaluation of multi-scale hyperspectral reflectance and emittance image data for remote mineral mapping in northeastern Death Valley National Park, California and Oasis Valley, Nevada

    NASA Astrophysics Data System (ADS)

    Aslett, Zan

    This dissertation focuses upon the analyses of hyperspectral reflectance and thermal emission image data to remotely detect and map surficial mineralogy in an arid environment in southern Nevada and southeastern California. It includes four manuscripts prepared for submission to peer-reviewed journals, which are presented as single chapters. The research involves the use of longwave-infrared (LWIR) hyper- and multi-spectral measurements made from ground, aerial, and spaceborne perspectives of sedimentary and meta-sedimentary geologic units in northeastern Death Valley National Park, California and both shortwave-infrared (SWIR) and LWIR hyperspectral measurements in an area of diverse Paleozoic and Tertiary geology in Oasis Valley, Nevada. In Chapter 1, a brief overview of the dissertation is provided, including background on reflected and thermal-infrared mineral spectroscopy; remote sensing; the impacts of spatial and spectral resolution upon the ability to detect, identify, and map minerals using remote sensing image data; and the use of combined reflectance and emittance image data to better map minerals. In Chapter 2, ground-based SEBASS LWIR hyperspectral image data is analyzed in order to determine the utility of very high resolution remotely-sensed emittance measurements to delineate late-Proterozoic and Paleozoic sedimentary lithologies of an outcrop at Hell's Gate, Death Valley. In Chapter 3, airborne SEBASS image data over Boundary Canyon are analyzed in conjunction with moderate-scale geologic maps and laboratory measurements to map minerals associated with sedimentary and meta-sedimentary rocks and important in recognizing a detachment fault structure, as well as metamorphic facies. In Chapter 4, ground-based and aerial SEBASS, aerial MASTER, and spaceborne ASTER emittance measurements are compared over two study sites to determine what repercussions viewing perspective and spatial, spectral, and radiometric resolutions have upon remote identification

  8. Kinematics at the intersection of the Garlock and Death Valley fault zones, California: Integration of TM data and field studies

    NASA Technical Reports Server (NTRS)

    Abrams, Michael; Verosub, Ken; Finnerty, Tony; Brady, Roland

    1987-01-01

    The Garlock and Death Valley fault zones in SE California are two active strike-slip faults coming together on the east side of the Avawatz Mtns. The kinematics of this intersection, and the possible continuation of either fault zone, are being investigated using a combination of field mapping, and processing and interpretation of remotely sensed image data. Regional and local relationships are derivable from Thematic Mapper data (30 m resolution), including discrimination and relative age dating of alluvial fans, bedrock mapping, and fault mapping. Aircraft data provide higher spatial resolution over more limited areas. Hypotheses being considered are: (1) the Garlock fault extends east of the intersection; (2) the Garlock fault terminates at the intersection and the Death Valley fault continues southeastward; and (3) the Garlock fault has been offset right laterally by the Death Valley fault which continues to the southeast. Preliminary work indicates that the first hypothesis is invalid. From kinematic considerations, image analysis, and field work the third hypothesis is favored. The projected continuation of the Death Valley zone defines the boundary between the Mojave crustal block and the Basin and Range block.

  9. Modeling and validation of a 3D velocity structure for the Santa Clara Valley, California, for seismic-wave simulations

    USGS Publications Warehouse

    Hartzell, S.; Harmsen, S.; Williams, R.A.; Carver, D.; Frankel, A.; Choy, G.; Liu, P.-C.; Jachens, R.C.; Brocher, T.M.; Wentworth, C.M.

    2006-01-01

    A 3D seismic velocity and attenuation model is developed for Santa Clara Valley, California, and its surrounding uplands to predict ground motions from scenario earthquakes. The model is developed using a variety of geologic and geophysical data. Our starting point is a 3D geologic model developed primarily from geologic mapping and gravity and magnetic surveys. An initial velocity model is constructed by using seismic velocities from boreholes, reflection/refraction lines, and spatial autocorrelation microtremor surveys. This model is further refined and the seismic attenuation is estimated through waveform modeling of weak motions from small local events and strong-ground motion from the 1989 Loma Prieta earthquake. Waveforms are calculated to an upper frequency of 1 Hz using a parallelized finite-difference code that utilizes two regions with a factor of 3 difference in grid spacing to reduce memory requirements. Cenozoic basins trap and strongly amplify ground motions. This effect is particularly strong in the Evergreen Basin on the northeastern side of the Santa Clara Valley, where the steeply dipping Silver Creek fault forms the southwestern boundary of the basin. In comparison, the Cupertino Basin on the southwestern side of the valley has a more moderate response, which is attributed to a greater age and velocity of the Cenozoic fill. Surface waves play a major role in the ground motion of sedimentary basins, and they are seen to strongly develop along the western margins of the Santa Clara Valley for our simulation of the Loma Prieta earthquake.

  10. Interpretive geologic cross sections for the Death Valley regional flow system and surrounding areas, Nevada and California

    SciTech Connect

    D.S. Sweetkind; R.P. Dickerson; R.J. Blakely; P.D. Denning

    2001-11-09

    This report presents a network of 28 geologic cross sections that portray subsurface geologic relations within the Death Valley regional ground-water system, a ground-water basin that encompasses a 3 degree x 3 degree area (approximately 70,000 square kilometers) in southern Nevada and eastern California. The cross sections transect that part of the southern Great Basin that includes Death Valley, the Nevada Test Site, and the potential high-level nuclear waste underground repository at Yucca Mountain. The specific geometric relationships portrayed on the cross sections are discussed in the context of four general sub-regions that have stratigraphic similarities and general consistency of structural style: (1) the Nevada Test Site vicinity; (2) the Spring Mountains, Pahrump Valley and Amargosa Desert region; (3) the Death Valley region; and (4) the area east of the Nevada Test Site. The subsurface geologic interpretations portrayed on the cross sections are based on an integration of existing geologic maps, measured stratigraphic sections, published cross sections, well data, and geophysical data and interpretations. The estimated top of pre-Cenozoic rocks in the cross sections is based on inversion of gravity data, but the deeper parts of the sections are based on geologic conceptual models and are more speculative.

  11. Potential for using the Upper Coachella Valley ground-water basin, California, for storage of artificially recharged water

    USGS Publications Warehouse

    Mallory, Michael J.; Swain, Lindsay A.; Tyley, Stephen J.

    1980-01-01

    This report presents a preliminary evaluation of the geohydrologic factors affecting storage of water by artificial recharge in the upper Coachella Valley, Calif. The ground-water basin of the upper Coachella Valley seems to be geologically suitable for large-scale artificial recharge. A minimum of 900 ,000 acre-feet of water could probably be stored in the basin without raising basinwide water levels above those that existed in 1945. Preliminary tests indicate that a long-term artificial recharge rate of 5 feet per day may be feasible for spreading grounds in the basin if such factors as sediment and bacterial clogging can be controlled. The California Department of Water Resources, through the Future Water Supply Program, is investigating the use of ground-water basins for storage of State Water Project water in order to help meet maximum annual entitlements to water project contractors. (USGS)

  12. Cone penetration tests and soil borings at the Mason Road site in Green Valley, Solano County, California

    USGS Publications Warehouse

    Bennett, Michael J.; Noce, Thomas E.; Lienkaemper, James J.

    2011-01-01

    In support of a study to investigate the history of the Green Valley Fault, 13 cone penetration test soundings and 3 auger borings were made at the Mason Road site in Green Valley, Solano County, California. Three borings were made at or near two of the cone penetration test soundings. The soils are mostly clayey with a few sandy layers or lenses. Fine-grained soils range from low plasticity sandy lean clay to very plastic fat clay. Lack of stratigraphic correlation in the subsurface prevented us from determining whether any channels had been offset at this site. Because the soils are generally very clayey and few sand layers or lenses are loose, the liquefaction potential at the site is very low.

  13. Population Structure of Xylella fastidiosa Associated with Almond Leaf Scorch Disease in the San Joaquin Valley of California.

    PubMed

    Lin, Hong; Islam, Md Sajedul; Cabrera-La Rosa, Juan C; Civerolo, Edwin L; Groves, Russell L

    2015-06-01

    Xylella fastidiosa causes disease in many commercial crops, including almond leaf scorch (ALS) disease in susceptible almond (Prunus dulcis). In this study, genetic diversity and population structure of X. fastidiosa associated with ALS disease were evaluated. Isolates obtained from two almond orchards in Fresno and Kern County in the San Joaquin Valley of California were analyzed for two successive years. Multilocus simple-sequence repeat (SSR) analysis revealed two major genetic clusters that were associated with two host cultivars, 'Sonora' and 'Nonpareil', respectively, regardless of the year of study or location of the orchard. These relationships suggest that host cultivar selection and adaptation are major driving forces shaping ALS X. fastidiosa population structure in the San Joaquin Valley. This finding will provide insight into understanding pathogen adaptation and host selection in the context of ALS disease dynamics. PMID:25807309

  14. Dissolved-selenium data for wells in the western San Joaquin Valley, California, February to July 1985

    USGS Publications Warehouse

    Neil, J.M.

    1986-01-01

    Water samples were collected for selenium analysis from 63 wells in western San Joaquin Valley, California, during February to July 1985. Results of the data collection indicate that dissolved selenium concentrations ranged from less than 1 to 120 micrograms per liter; more than 50 percent of the wells sampled had concentrations of less than 1 microgram per liter. Four additional samples collected from public supply wells in the western valley had concentrations ranging from less than 1 to 2 micrograms per liter. All samples from five public supply wells east of the study area had concentrations less than 1 microgram per liter. The U.S. Environmental Protection Agency 's drinking-water standard of 10 micrograms per liter for selenium was slightly exceeded in 2 of 39 domestic wells (11 and 13 micrograms per liter) and substantially exceeded in 2 of 11 irrigation and agricultural wells (55 and 120 micrograms per liter). (USGS)

  15. Logs and Scarp Data from a Paloseismic Investigation of the Surprise Valley Fault Zone, Modoc County, California

    USGS Publications Warehouse

    Personius, Stephen F.; Crone, Anthony J.; Machette, Michael N.; Lidke, David J.; Bradley, Lee-Ann; Mahan, Shannon

    2007-01-01

    This report contains field and laboratory data from a paleoseismic study of the Surprise Valley fault zone near Cedarville, California. The 85-km-long Surprise Valley fault zone forms the western active margin of the Basin and Range province in northeastern California. The down-to-the-east normal fault is marked by Holocene fault scarps along most of its length, from Fort Bidwell on the north to near the southern end of Surprise Valley. We studied the central section of the fault to determine ages of paleoearthquakes and to better constrain late Quaternary slip rates, which we hope to compare to deformation rates derived from a recently established geodetic network in the region (Hammond and Thatcher, 2005; 2007). We excavated a trench in June 2005 across a prominent fault scarp on pluvial Lake Surprise deltaic sediments near the mouth of Cooks Canyon, 4 km north of Cedarville. This site was chosen because of the presence of a well-preserved fault scarp and its development on lacustrine deposits thought to be suitable for luminescence dating. We also logged a natural exposure of the fault in similar deltaic sediments near the mouth of Steamboat Canyon, 11 km south of Cedarville, to better understand the along-strike extent of surface ruptures. The purpose of this report is to present photomosaics, trench, drill hole, and stream exposure logs; scarp profiles; and fault slip, tephrochronologic, radiocarbon, luminescence, and unit description data obtained during this investigation. We do not attempt to use the data presented herein to construct a paleoseismic history of this part of the Surprise Valley fault zone; that history will be the subject of a future report.

  16. A Conceptual Model for Floodplains in California's Central Valley and a Method for Identifying Representative Floods and Floodplains

    NASA Astrophysics Data System (ADS)

    Opperman, J. J.; Andrews, E.; Bozkurt, S.; Mount, J. F.; Moyle, P. B.

    2005-05-01

    Currently, significant resources are being invested in restoring native species and ecosystems in California's Central Valley and the Sacramento-San Joaquin Delta, led by the California Bay-Delta Authority (CBDA). Functioning floodplains provide numerous ecological benefits and floodplain restoration is emerging as important component of ecosystem restoration in this region. We developed a conceptual model that describes the linkages between physical (hydrologic and geomorphic) processes and ecosystem processes and responses on Central Valley floodplains. Central to this model is the role of hydrological variability in driving topographic diversity, ecosystem heterogeneity and ecological processes. We attempt to capture the extremely complex linkages between hydrological variability and ecosystem response through `representative floods.' A representative flood encompasses a set of hydrological variables, such as frequency and duration, which produce a characteristic suite of ecological benefits. For example, frequent, long duration flooding in the spring provides spawning and rearing habitat for native fish and promotes high phytoplankton productivity which can be exported to riverine and delta ecosystems. Less frequent, higher magnitude floods drive extensive geomorphic change upon the floodplain, creating topographic and, ultimately, ecological heterogeneity. Here we describe a process to define, map, and quantify the area inundated by a particular representative flood in the Sacramento River valley. To illustrate we identify the area inundated by a frequent (exceedance probability of 67%), long duration (> 7 days) flood that occurs in the spring. We used paired gauges to find the stage corresponding to the representative flood parameters and compared a plane connecting the gauges to topography in the intervening reach of river. We found that this type of representative flood inundates very little area in the Sacramento Valley; primary areas of inundation are

  17. Decision analysis framing study; in-valley drainage management strategies for the western San Joaquin Valley, California

    USGS Publications Warehouse

    Presser, Theresa S.; Jenni, Karen E.; Nieman, Timothy; Coleman, James

    2010-01-01

    Constraints on drainage management in the western San Joaquin Valley and implications of proposed approaches to management were recently evaluated by the U.S. Geological Survey (USGS). The USGS found that a significant amount of data for relevant technical issues was available and that a structured, analytical decision support tool could help optimize combinations of specific in-valley drainage management strategies, address uncertainties, and document underlying data analysis for future use. To follow-up on USGS's technical analysis and to help define a scientific basis for decisionmaking in implementing in-valley drainage management strategies, this report describes the first step (that is, a framing study) in a Decision Analysis process. In general, a Decision Analysis process includes four steps: (1) problem framing to establish the scope of the decision problem(s) and a set of fundamental objectives to evaluate potential solutions, (2) generation of strategies to address identified decision problem(s), (3) identification of uncertainties and their relationships, and (4) construction of a decision support model. Participation in such a systematic approach can help to promote consensus and to build a record of qualified supporting data for planning and implementation. In December 2008, a Decision Analysis framing study was initiated with a series of meetings designed to obtain preliminary input from key stakeholder groups on the scope of decisions relevant to drainage management that were of interest to them, and on the fundamental objectives each group considered relevant to those decisions. Two key findings of this framing study are: (1) participating stakeholders have many drainage management objectives in common; and (2) understanding the links between drainage management and water management is necessary both for sound science-based decisionmaking and for resolving stakeholder differences about the value of proposed drainage management solutions. Citing

  18. Groundwater quality in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts, California

    USGS Publications Warehouse

    Parsons, Mary C.; Belitz, Kenneth

    2014-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State’s untreated groundwater quality and increases public access to groundwater-quality information. Selected groundwater basins in the Borrego Valley, Central Desert, and Low-Use Basins of the Mojave and Sonoran Deserts constitute one of the study units being evaluated.

  19. Chemical composition data and calculated aquifer temperature for selected wells and springs of Honey Lake Valley, California

    USGS Publications Warehouse

    Mariner, R.H.; Presser, T.S.; Evans, William C.

    1976-01-01

    Major element, minor element, and gas composition data are tabulated for 15 springs and wells in Honey Lake Valley, California. Wendel and Amedee hot springs issue Na-S04-C1 waters at boiling or near boiling temperatures; the remaining springs and wells issue Na-HC03 waters at temperatures ranging from 14 to 33 deg C. Gases escaping from the hot springs are principally nitrogen with minor amounts of methane. The geothermometers calculated from the chemical data are also tabulated for each spring. (Woodard-USGS)

  20. Analysis of the quality of image data acquired by the LANDSAT-4 thematic mapper and multispectral scanners. [Central Valley, California

    NASA Technical Reports Server (NTRS)

    Colwell, R. N. (Principal Investigator)

    1983-01-01

    Image products and numeric data were extracted from both TM and MSS data in an effort to evaluate the quality of these data for interpreting major agricultural resources and conditions in California's Central Valley. The utility of TM data appears excellent for meeting most of the inventory objectives of the agricultural resource specialist. These data should be extremely valuable for crop type and area proportion estimation, for updating agricultural land use survey maps at 1:24,000-scale and smaller, for field boundary definition, and for determining the size and location of individual farmsteads.

  1. Digital tabulation of stratigraphic data from oil and gas wells in Cuyama Valley and surrounding areas, central California

    USGS Publications Warehouse

    Sweetkind, Donald S.; Bova, Shiera C.; Langenheim, V.E.; Shumaker, Lauren E.; Scheirer, Daniel S.

    2013-01-01

    Stratigraphic information from 391 oil and gas exploration wells from Cuyama Valley, California, and surrounding areas are herein compiled in digital form from reports that were released originally in paper form. The Cuyama Basin is located within the southeasternmost part of the Coast Ranges and north of the western Transverse Ranges, west of the San Andreas fault. Knowledge of the location and elevation of stratigraphic tops of formations throughout the basin is a first step toward understanding depositional trends and the structural evolution of the basin through time, and helps in understanding the slip history and partitioning of slip on San Andreas and related faults.

  2. 78 FR 894 - Interim Final Determination To Stay Sanctions, Imperial County Air Pollution Control District

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-07

    ... AGENCY 40 CFR Part 52 Interim Final Determination To Stay Sanctions, Imperial County Air Pollution... of revisions to the Imperial County Air Pollution Control District (ICAPCD) portion of the California... July 8, 2010 (75 FR 39366), we published a limited approval and limited disapproval of the...

  3. Quaternary N-S shortening across the Garlock fault in Pilot Knob Valley, California

    NASA Astrophysics Data System (ADS)

    Rittase, W. M.; Walker, J. D.; Kirby, E.; McDonald, E.; Gosse, J.; Spencer, J. Q.; Wan, E.; Herrs, A. J.

    2011-12-01

    New constraints on differential vertical motions along the Garlock fault (GF) in eastern Pilot Knob Valley (PKV) provide insight into the interactions between the Panamint Valley fault system (PVFS) and the GF. The nature of strain transfer between orthogonal active fault systems such as occurs where faults of the Eastern California Shear Zone apparently accommodate dextral shear both north and south of the sinistral GF is a question of first-order importance for both the dynamics of deforming lithosphere and hazard. New mapping (based on field as well as both airborne and ground-based LiDAR) and chronology of Quaternary deposits exposed along the GF place bounds on the vertical components of recent deformation and include: (1) 2 10Be depth profiles, (2) soil descriptions and (3) tephrochronologic correlation of Quaternary volcanic deposits. Here we focus on two terrace treads adjacent to the GF and one adjacent to the southern Slate Range (SSR), which are displaced vertically relative to base-level. Uplift of the two terraces adjacent to the GF are inferred from modern stream channel incisions. A ~46 ka 10Be profile age for a 16-m-high terrace tread adjacent to the GF suggests a minimum differential uplift rate of ~0.34 mm/yr. A ~56 ka 10Be profile age from a 12.5-m-high tread located 4.5 km west on the GF suggests a differential uplift rate of ~0.22 mm/yr. A 25.5-m-high terrace adjacent to the SSR was dated via TCN, OSL and PDI. Acquiring reliable TCN and OSL data were problematic here. However, a soil PDI age estimate of ~164 ka brackets the maximum age of uplift and thus a minimum uplift rate of ~0.16 mm/yr here. Tephrochronologic data bracket the minimum age of the PKV at ~0.7 Ma (new unit). These sediments sit up to 430 m above the modern PKV floor. If faults controlling ~430 m of uplifted PKV sediments dip 70-80°, 155-76 m of N-S shortening is expected between the GF and SSR. A long-term uplift rate of ~0.61 mm/yr and N-S shortening rate of 0.22-0.11 mm

  4. Reconstructing temporal variations in fault slip from footwall topography: An example from Saline Valley, California (Invited)

    NASA Astrophysics Data System (ADS)

    Kirby, E.; Regalla, C.; Ouimet, W. B.; Bierman, P. R.

    2010-12-01

    It is becoming increasingly apparent that many intra-plate fault systems exhibit significant variability their rates of displacement over timescales ranging from 104 - 106 yr. Whether such variability arises simply as a consequence of fault system evolution or whether it reflects temporal changes in the rate of loading in the deep crust remains a first-order question. Because most records of fault slip at these timescales rely on geomorphic markers, inherently ephemeral features in the landscape, characterizing the history of fault slip through time can be difficult and is usually limited to environments with high rates of sediment deposition. In erosional landscapes, however, changes in the throw rates of fault systems are expected to engender systematic changes in landscape topography as channels and hillslopes adjust to changes in relative base level. Here we combine quantitative analysis of stream profiles with measurements of erosion rate (using detrital inventories of 10Be in sediment) from footwall catchments in the Inyo Mountains, in eastern California, to recognize and place constraints on the timing and of a sustained acceleration in fault slip along the range-front fault system. The Inyo Mountains are the footwall block to an active fault system along the western margin of Saline Valley; relief between the range and valley floor averages ~3 km. Normal-oblique slip along the range-front fault is linked to strike-slip displacement on the Hunter Mountain fault. Estimates for the onset of slip along this system range from 2.8 - 4.0 Ma, implying average slip rates of 2.1 - 3.3 mm/yr. However, geodetic measures suggest modern slip rates reach or exceed ~4.5 mm/yr. Analysis of channel profiles draining the Inyo Range reveals pronounced knickpoints that separate relatively low-gradient headwater reaches from exceedingly steep lower reaches. Knickpoints are only present along channels that cross the range-front fault, are developed within a single lithology, and

  5. 76 FR 45212 - Revisions to the California State Implementation Plan, San Joaquin Valley Unified Air Pollution...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-28

    ... Air Pollution Control District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: In this action, we are proposing to approve San Joaquin Valley Unified Air Pollution Control... the environment. San Joaquin Valley Unified Air Pollution Control District SJVUAPCD is an...

  6. Deformation of the Long Valley Caldera, California: Inferences from measurements from 1988 to 2001

    USGS Publications Warehouse

    Langbein, J.O.

    2003-01-01

    Two periods of volcanic unrest occurred between 1989 and 1998 in the Long Valley Caldera, eastern California. Numerous earthquakes were recorded, and these periods of unrest were documented with high-precision geodetic measurements. The first round of unrest started rapidly in late 1989 and slowly decreased in rate through the early 1990s. For this interval there are both leveling and two-color electronic distance meter (EDM) measurements. The second round of unrest started slowly in mid-1997, climaxed in late 1997, and rapidly returned to quiescence by mid-1998. Deformation was recorded by both the two-color EDM and continuous GPS. Both episodes require inflation at 6-7 km beneath the resurgent dome, and both episodes had roughly 0.1 m extension across the resurgent dome. In addition, the data presented here suggest that there is a deeper, 10-20 km, inflation source beneath the south moat of the caldera. For both episodes, the better-resolved inflation beneath the resurgent dome is a near-vertical, prolate spheroid rather than an isotropic source, which suggests that magma came up through vertical cracks. However, the modeling suggests that the location changed with the depth from 6.0 to 6.7 km for the later episode. In contrast to the earlier episode, the 1997-1998 episode has additional deformation in the south moat, where the simplest model is that of a right-lateral slip on a steeply dipping plane that is defined by the location of earthquakes in the south moat. Models of the time-dependent behavior suggest that slip on this fault occurred from late November through December 1997, corresponding to the time of greatest moment release by the earthquake swarm in the south moat. Confounding the interpretation of these data is an active geothermal field near the center of the EDM network and adjacent to the south moat and resurgent dome. Additional modeling of leveling and EDM data within the geothermal field during a period of low rate of inflation of the dome

  7. Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location.

    PubMed

    Sardiñas, Hillary S; Tom, Kathleen; Ponisio, Lauren Catherine; Rominger, Andrew; Kremen, Claire

    2016-03-01

    The delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. Pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. Current models that map pollination coverage in agricultural regions utilize landscape-level estimates of floral availability and nesting incidence inferred from expert opinion, rather than direct assessments. Foraging distance is often derived from proxies of bee body size, rather than direct measurements of foraging that account for behavioral responses to floral resource type and distribution. The lack of direct measurements of nesting incidence and foraging distances may lead to inaccurate mapping of pollination services. We examined the role of local-scale floral resource presence from hedgerow plantings on nest incidence of ground-nesting bees in field margins and within monoculture, conventionally managed sunflower fields in California's Central Valley. We tracked bee movement into fields using fluorescent powder. We then used these data to simulate the distribution of pollination services within a crop field. Contrary to expert opinion, we found that ground-nesting native bees nested both in fields and edges, though nesting rates declined with distance into field. Further, we detected no effect of field-margin floral enhancements on nesting. We found evidence of an exponential decay rate of bee movement into fields, indicating that foraging predominantly occurred in less than 1% of medium-sized bees' predicted typical foraging range. Although we found native bees nesting within agricultural fields, their restricted foraging movements likely centralize pollination near nest sites. Our data thus predict a heterogeneous distribution of pollination services

  8. Near real-time monitoring of surface deformation at Long Valley Caldera, California (Invited)

    NASA Astrophysics Data System (ADS)

    Ji, K.; Llenos, A. L.; Herring, T.

    2013-12-01

    Continuous monitoring of volcanic activity enables us to detect changes from usual activity, issue alerts of impending eruptions and thereby reduce volcanic risk. We have developed a near real-time monitoring tool for surface deformation: the Targeted Projection Operator (TPO). TPO is simple, fast, and easily applied whenever new data are available. With Global Positioning System (GPS) data, we have used TPO for continuous monitoring of surface deformation in the Long Valley Caldera (LVC) region in eastern California. TPO projects GPS position time series onto a target spatial pattern and obtains the amplitude of the projection at each epoch. For this, we assume that a deformation event (i.e., an inflationary or deflationary event) has the same spatial pattern as past events but with possibly different amplitude. This assumption is reasonable for the recent quiet phase in LVC because the 2007-2009 inflation is similar to the 2009-2010 deflation with respect to the deformation pattern. We selected horizontal pattern of the 2009-2010 event along which the GPS data are projected to recover the time-varying amplitudes. Large changes in amplitude imply changes in strength of the event. An anomalous change can be detected by comparing with amplitudes during relatively quiet time periods. Growing misfits between the TPO spatial pattern and the spatial variations of the GPS pattern, indicate changes in the deformation mechanism which can then be explored to assess whether potentially new mechanisms are developing. So far this has not been the case for LVC; the current spatial patterns of deformation match the shape deduced for the 2007-2009 inflation event. TPO shows that LVC has experienced inflation since late 2011 although the rate briefly slowed down in May and October 2012 and has started to slow again since June 2013. The rate of this event is about four times faster than the 2007-2009 inflation event and is consistent with a Mogi source located beneath the resurgent

  9. Monitoring the Thermal Regime at Hot Creek and Vicinity, Long Valley Caldera, Eastern California

    NASA Astrophysics Data System (ADS)

    Clor, L. E.; Hurwitz, S.; Howle, J.

    2015-12-01

    Hot Creek Gorge contains the most obvious surface expression of the hydrothermal system in Long Valley Caldera, California, discharging 200-300 L/s of thermal water according to USGS measurements made since 1988. Formerly, Hot Creek was a popular public swimming area, but it was closed in 2006 due to unpredictable temperature fluctuations and sporadic geysering of thermal water within the creek (Farrar et al. USGS Fact Sheet2007-3045). The USGS has monitored the thermal regime in the area since the mid-1980s, including a long-term series of studies 0.6 km away at well CH-10b. Temperature measurements in the ~100 m deep well, which have been performed on an intermittent basis since it was drilled in 1983, reveal a complex temperature profile. Temperatures increase with depth to a maximum at about 45 meters below the ground surface, and then decrease steadily to the bottom of the well. The depth of the temperature maximum in the well (~45 m) corresponds to an elevation of ~2,120 m, roughly equivalent to the elevation of Hot Creek, and appears to sample the same hydrothermal flow system that supplies thermal features at the surface in the gorge. Starting in the early 1990s, the maximum temperature in CH-10b rose from 93.4°C to its peak in 2007 at 101.0°C. A cooling trend was observed beginning in 2009 and continues to present (99.3°C in June 2015). As the input into CH-10b is at the elevation of the creek, it exhibits the potential for response to thermal events at Hot Creek, and could provide a useful tool for monitoring future hazards. On short timescales, CH-10b also responds to large global earthquakes, greater than ~M7. These responses are captured with continuously logged high-frequency data (5s), and are usually characterized by a co-seismic water level drop of up to ten centimeters. Water levels tend to recover to pre-earthquake levels within a few hours to days.

  10. Ecohydrology of Wetlands Occurring on Perched Seasonally Saturated Water Tables in the Central Valley of California

    NASA Astrophysics Data System (ADS)

    McCarten, N. F.; Harter, T.

    2010-12-01

    The Central Valley, California has extensive areas of shallow perched groundwater systems associated with geomorphic terraces. Early season water supply is derived from precipitation (PPT) that has infiltrated into soils underlain by a near surface aquitard, typically at less than 2 m depth. Early season water input is regulated by the hydraulic conductivity of the (clay-) loamy soils and by surface and aquitard slope of the local catchments associated with these old alluvial landforms. Research on these landforms and shallow aquifers has identified a complex PPT and evapotranspiration (ET) sensitive system that includes shallow depressions that seasonally produce water table derived wetlands (“vernal pools”). These wetlands have been recognized for a very high level of plant and invertebrate species diversity including endangered species. Our work on these seasonal perched systems shows that as much as 80 percent of the soil column above the aquitard is saturated, during average to high rainfall years, for up to 90 to 120 days. Soil surface topographic depressions reduce the soil depth to the aquitard. Where the water table of this perched system intercepts the land surface, vernal pools develop. The perched groundwater drains into seasonal surface drainages that ultimately supply the Sacramento and San Joaquin rivers. At the end of the rainy season, both the vernal pools and the perched aquifer rapidly and synchronously disappear. Once the soil is unsaturated, water flow is vertically upward due to ET. Aquatic and wetland adapted plant species develop within the basins along a depth gradient. Variably saturated modeling of this system was conducted using HYDRUS 2D/3D. Climate inputs were from local and regional weather stations that measure and calculate daily PPT and ET, respectively. Initial conditions and calibration of the domain were based on field measurements using pressure transducers and soil moisture sensors. Soil pressure flux was measured using a

  11. SRTM Stereo Pair with Landsat Overlay: Los Angeles to San Joaquin Valley, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    California's topography poses challenges for road builders. Northwest of Los Angeles, deformation of Earth's crust along the Pacific-North American crustal plate boundary has made transportation difficult. Direct connection between metropolitan Los Angeles (image lower left) and California's Central Valley (image top center) through the rugged terrain seen on the left side of this image was long avoided in favor of longer, but easier paths. However, over the last century, three generations of roads have traversed this terrain. The first was 'The Ridge Route', a two-lane road, built in 1915, which followed long winding ridge lines that included 697curves. The second, built in 1933, was to become four-lane U.S. Highway 99. It generally followed widened canyon bottoms. The third is the current eight lane Interstate 5 freeway, built in the 1960s, which is generally notched into hillsides, but also includes a stretch of several miles where the two directions of travel are widely separated and driving is 'on the left', a rarity in the United States. Such an unusual highway configuration was necessary in order to optimize the road grades for uphill and downhill traffic in this topographically challenging setting.

    This stereoscopic image was generated by draping a Landsat satellite image over a preliminary SRTM elevation model. Two differing perspectives were then calculated, one for each eye. They can be seen in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing), or by downloading and printing the image pair, and viewing them with a stereoscope. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30 meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive

  12. Characterizing Recent Slip on the Kuikui Fault, a Link Between the Green Valley and Bartlett Springs Fault Zones, Wilson Valley, Northern California.

    NASA Astrophysics Data System (ADS)

    Lienkaemper, J. J.; DeLong, S. B.; McPherson, R. C.; Mielke, J.; Avdievitch, N.; Pickering, A.; Lloyd, C.

    2014-12-01

    The Green Valley and Bartlett Springs faults (GVF-BSF) together form the third largest branch of the dextral San Andreas transform fault system in northern California. Wilson Valley lies at the center of a tectonic pull-apart basin formed in the 2.5-km stepover between the Hunting Creek fault (northernmost section of the GVF) and the Highway-20 section of the BSF. A major regional drainage, Cache Creek flows through this depression and has been offset ~6 km right-laterally by the GVF-BSF during the Quaternary. We recently discovered the Kuikui fault, a dextral-oblique slip fault within the stepover, using high-resolution imagery from LiDAR acquired by USGS in 2011 along major northern California fault zones (ARRA11_USGS, DOI: 10.5069/G9H70CRD, http://dx.doi.org/10.5069/G9H70CRD). The Kuikui fault is ~2-3 km in length and forms steep, well-preserved scarps up to ~2.5 m high. It has only subtle expression of dextral slip, so its ratio of dip slip to strike slip is uncertain. Any evidence of large paleoearthquakes in the Wilson Valley stepover might indicate rupture of either the GVF or the BSF or both together, and timing information could be used to correlate events with other paleoseismic sites on the fault system. Additionally, fault creep has been documented on both the Highway 20 and Hunting Creek fault sections, so that any fault offset on the Kuikui fault might also include some aseismic slip. Because wilderness regulations required manual excavation, several participants from USGS, HSU, other colleagues and volunteers together dug an 8-m long by ≤1 m deep trench by hand to expose faulting in thin layers of alluvium deposited across the Kuikui fault. The youngest, and currently active soil layer is vertically offset by a minimum of 7 cm on a single fault strand. A much broader fault zone suggests larger movement has occurred. This exposure did not allow us to discriminate whether slip occurred as creep or by dynamic rupture. Future additional exposures may

  13. PoroTomo Subtask 3.2 Data files from the Distributed Acoustic Sensing experiment at Garner Valley, California

    DOE Data Explorer

    Chelsea Lancelle

    2013-09-11

    In September 2013, an experiment using Distributed Acoustic Sensing (DAS) was conducted at Garner Valley, a test site of the University of California Santa Barbara (Lancelle et al., 2014). This submission includes all DAS data recorded during the experiment. The sampling rate for all files is 1000 samples per second. Any files with the same filename but ending in _01, _02, etc. represent sequential files from the same test. Locations of the sources are plotted on the basemap in GDR submission 481, titled: "PoroTomo Subtask 3.2 Sample data from a Distributed Acoustic Sensing experiment at Garner Valley, California (PoroTomo Subtask 3.2)." Lancelle, C., N. Lord, H. Wang, D. Fratta, R. Nigbor, A. Chalari, R. Karaulanov, J. Baldwin, and E. Castongia (2014), Directivity and Sensitivity of Fiber-Optic Cable Measuring Ground Motion using a Distributed Acoustic Sensing Array (abstract # NS31C-3935), AGU Fall Meeting. 
https://agu.confex.com/agu/fm1/meetingapp.cgi#Paper/19828 The e-poster is available at: https://agu.confex.com/data/handout/agu/fm14/Paper_19828_handout_696_0.pdf

  14. 78 FR 49992 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ... of the California State Implementation Plan (SIP). These revisions concern sulfur oxide emissions... Smelters/Sulfur Oxides;'' VCAPCD Rule 37, ``Project XL;'' and VCAPCD Rule 67, ``Vacuum Producing...

  15. Hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction, San Joaquin Valley, California

    USGS Publications Warehouse

    Sneed, Michelle

    2001-01-01

    This report summarizes hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction in the San Joaquin Valley, a broad alluviated intermontane structural trough that constitutes the southern two-thirds of the Central Valley of California. These values will be used to constrain a coupled ground-water flow and aquifer-system compaction model of the western San Joaquin Valley called WESTSIM. A main objective of the WESTSIM model is to evaluate potential future land subsidence that might occur under conditions in which deliveries of imported surface water for agricultural use are reduced and ground-water pumping is increased. Storage values generally are components of the total aquifer-system storage and include inelastic and elastic skeletal storage values of the aquifers and the aquitards that primarily govern the potential amount of land subsidence. Vertical hydraulic conductivity values generally are for discrete thicknesses of sediments, usually aquitards, that primarily govern the rate of land subsidence. The data were compiled from published sources and include results of aquifer tests, stress-strain analyses of borehole extensometer observations, laboratory consolidation tests, and calibrated models of aquifer-system compaction.

  16. Geohydrology of the Antelope Valley Area, California and design for a ground-water-quality monitoring network

    USGS Publications Warehouse

    Duell, L.F.

    1987-01-01

    A basinwide ideal network and an actual network were designed to identify ambient groundwater quality, trends in groundwater quality, and degree of threat from potential pollution sources in Antelope Valley, California. In general, throughout the valley groundwater quality has remained unchanged, and no specific trends are apparent. The main source of groundwater for the valley is generally suitable for domestic, irrigation, and most industrial uses. Water quality data for selected constituents of some network wells and surface-water sites are presented. The ideal network of 77 sites was selected on the basis of site-specific criteria, geohydrology, and current land use (agricultural, residential, and industrial). These sites were used as a guide in the design of the actual network consisting of 44 existing wells. Wells are currently being monitored and were selected whenever possible because of budgetary constraints. Of the remaining ideal sites, 20 have existing wells not part of a current water quality network, and 13 are locations where no wells exist. The methodology used for the selection of sites, constituents monitored, and frequency of analysis will enable network users to make appropriate future changes to the monitoring network. (USGS)

  17. Can We Mitigate Climate Extremes using Managed Aquifer Recharge: Case Studies California Central Valley and South-Central Arizona, USA

    NASA Astrophysics Data System (ADS)

    Scanlon, B. R.; Reedy, R. C.; Faunt, C. C.; Pool, D. R.; Uhlman, K.

    2015-12-01

    Frequent long-term droughts interspersed with intense floods in the southwestern U.S. underscore the need to store more water to manage these climate extremes. Here we show how managed aquifer recharge can enhance drought resilience in the southwestern U.S. with ~ 70% of California under extreme drought and 75% of Arizona under moderate drought. Data on water sources, transportation, and users were compiled for managed aquifer recharge systems in the Central Valley and south-central Arizona. Groundwater depletion of 115 to 145 km3 in the 1900s created large subsurface reservoirs in thick alluvial basins in these regions. Large canals and aqueducts up to several 100 km long allow water to be imported from reservoirs, mostly in more humid regions. Imported water is either used instead of groundwater or is applied in surface spreading basins primarily during wet periods (≤1.3 km3/yr Central Valley, ≤0.7 km3/yr Arizona) and is extracted during droughts. The dominant water users include irrigators and municipalities both within and outside the managed aquifer recharge systems. Groundwater modeling indicates that recharge basins significantly increase groundwater storage in the Central Valley. Managed aquifer recharge systems significantly enhance drought resilience and increase sustainability of water resources in semiarid regions, complementing surface water reservoirs and conjunctive surface water/groundwater use by providing longer term storage.

  18. Fault-zone guided waves from explosions in the San Andreas fault at Parkfield and Cienega Valley, California

    USGS Publications Warehouse

    Li, Y.-G.; Ellsworth, W.L.; Thurber, C.H.; Malin, P.E.; Aki, K.

    1997-01-01

    Fault-zone guided waves were successfully excited by near-surface explosions in the San Andreas fault zone both at Parkfield and Cienega Valley, central California. The guided waves were observed on linear, three-component seismic arrays deployed across the fault trace. These waves were not excited by explosions located outside the fault zone. The amplitude spectra of guided waves show a maximum peak at 2 Hz at Parkfield and 3 Hz at Cienega Valley. The guided wave amplitude decays sharply with observation distance from the fault trace. The explosion-excited fault-zone guided waves are similar to those generated by earthquakes at Parkfield but have lower frequencies and travel more slowly. These observations suggest that the fault-zone wave guide has lower seismic velocities as it approaches the surface at Parkfield. We have modeled the waveforms as S waves trapped in a low-velocity wave guide sandwiched between high-velocity wall rocks, resulting in Love-type fault-zone guided waves. While the results are nonunique, the Parkfield data are adequately fit by a shallow wave guide 170 m wide with an S velocity 0.85 km/sec and an apparent Q ??? 30 to 40. At Cienega Valley, the fault-zone wave guide appears to be about 120 m wide with an S velocity 0.7 km/sec and a Q ??? 30.

  19. Pyrethroid insecticide concentrations and toxicity in streambed sediments and loads in surface waters of the San Joaquin Valley, California, USA

    USGS Publications Warehouse

    Domagalski, J.L.; Weston, D.P.; Zhang, M.; Hladik, M.

    2010-01-01

    Pyrethroid insecticide use in California, USA, is growing, and there is a need to understand the fate of these compounds in the environment. Concentrations and toxicity were assessed in streambed sediment of the San Joaquin Valley of California, one of the most productive agricultural regions of the United States. Concentrations were also measured in the suspended sediment associated with irrigation or storm-water runoff, and mass loads during storms were calculated. Western valley streambed sediments were frequently toxic to the amphipod, Hyalella azteca, with most of the toxicity attributable to bifenthrin and cyhalothrin. Up to 100% mortality was observed in some locations with concentrations of some pyrethroids up to 20 ng/g. The western San Joaquin Valley streams are mostly small watersheds with clay soils, and sediment-laden irrigation runoff transports pyrethroid insecticides throughout the growing season. In contrast, eastern tributaries and the San Joaquin River had low bed sediment concentrations (<1 ng/g) and little or no toxicity because of the preponderance of sandy soils and sediments. Bifenthrin, cyhalothrin, and permethrin were the most frequently detected pyrethroids in irrigation and storm water runoff. Esfenvalerate, fenpropathrin, and resmethrin were also detected. All sampled streams contributed to the insecticide load of the San Joaquin River during storms, but some compounds detected in the smaller creeks were not detected in the San Joaquin River. The two smallest streams, Ingram and Hospital Creeks, which had high sediment toxicity during the irrigation season, accounted for less than 5% of the total discharge of the San Joaquin River during storm conditions, and as a result their contribution to the pyrethroid mass load of the larger river was minimal. ?? 2010 SETAC.

  20. Culture and Imperialism.

    ERIC Educational Resources Information Center

    Said, Edward W.

    Growing out of a series of lectures given at universities in the United States, Canada, and England, this book reopens the dialogue between literature and the life of its time. It draws dramatic connections between the imperial endeavor and the culture that both reflected and reinforced it, describing a general pattern of relationships between the…