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Research about San Joaquin Valley

Source-linked reports with geographic coverage including San Joaquin Valley.

At least 55 records · Page 3Linked to original sources
USGS2002

September-March survival of female northern pintails radiotagged in San Joaquin Valley, California

To improve understanding of pintail ecology, we radiotagged 191 hatch-year (HY) and 228 after-hatch-year (AHY) female northern pintails ( Anas acuta ) in the San Joaquin Valley (SJV), and studied their survival throughout central California, USA, during September-March, 1991-1994. We used adjusted Akaike Information Criterion (AICc) values to contrast known-fate models and examine variation in survival rates relative to year, interval, wintering region (AJV, other central California), pintail age, body mass at capture, capture date, capture area, and radio type. The best-fitting model included only interval x year and age x body mass; the next 2 best-fitting models also included wintering region and capture date. Hunting caused 83% of the mortalities we observed, and survival was consistently lower during hunting than nonhunting intervals. Nonhunting and hunting mortality during early winter was highest during the 1991-1992 drought year. Early-winter survival improved during the study along with habitat conditions in the Grassland Ecological Area (EA), where most radiotagged pintails spent early winter. Survival was more closely related to body mass at capture for HY than AHY pintails, even after accounting for the later arrival (based on capture date) of HY pintails, suggesting HY pintails are less adept at improving their condition. Thus, productivity estimates based on harvest age ratios may be biased if relative vulnerability of HY and AHY pintails is assumed to be constant because fall body condition of pintails may vary greatly among years. Cumulative winter survival was 75.6% (95% CI = 68.3% to 81.7%) for AHY and 65.4% (56.7% to 73.1%) for HY female pintails. Daily odds of survival in the cotton-agriculture landscape of the SJV were -21.3% (-40.3% to +3.7%) lower than in the rice-agriculture landscape of the Sacramento Valley (SACV) and other central California areas. Higher hunting mortality may be 1 reason pintails have declined more in SJV than in SACV.

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USGS2001

Hydraulic and mechanical properties affecting ground-water flow and aquifer-system compaction, San Joaquin Valley, California

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.

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USGS1999

Simultaneous reduction of nitrate and selenate by cell suspensions of selenium-respiring bacteria

Washed-cell suspensions of Sulfurospirillum barnesii reduced selenate [Se(VI)] when cells were cultured with nitrate, thiosulfate, arsenate, or fumarate as the electron acceptor. When the concentration of the electron donor was limiting, Se(VI) reduction in whole cells was approximately fourfold greater in Se(VI)-grown cells than was observed in nitrate-grown cells; correspondingly, nitrate reduction was ∼11-fold higher in nitrate-grown cells than in Se(VI)-grown cells. However, a simultaneous reduction of nitrate and Se(VI) was observed in both cases. At nonlimiting electron donor concentrations, nitrate-grown cells suspended with equimolar nitrate and selenate achieved a complete reductive removal of nitrogen and selenium oxyanions, with the bulk of nitrate reduction preceding that of selenate reduction. Chloramphenicol did not inhibit these reductions. The Se(VI)-respiring haloalkaliphile Bacillus arsenicoselenatis gave similar results, but its Se(VI) reductase was not constitutive in nitrate-grown cells. No reduction of Se(VI) was noted for Bacillus selenitireducens , which respires selenite. The results of kinetic experiments with cell membrane preparations of S. barnesii suggest the presence of constitutive selenate and nitrate reduction, as well as an inducible, high-affinity nitrate reductase in nitrate-grown cells which also has a low affinity for selenate. The simultaneous reduction of micromolar Se(VI) in the presence of millimolar nitrate indicates that these organisms may have a functional use in bioremediating nitrate-rich, seleniferous agricultural wastewaters. Results with 75 Se-selenate tracer show that these organisms can lower ambient Se(VI) concentrations to levels in compliance with new regulations proposed for release of selenium oxyanions into the environment.

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USGS1997

Mass balance approach to selenium cycling through the San Joaquin Valley, sources to river to bay

Surface and ground waters of the Central Valley of California (e.g., rivers, dams, off-stream storage reservoirs, pumping facilities, irrigation and drinking water supply canals, agricultural drainage canals) are part of a hydrologic system that makes up a complex ecosystem extending from the riparian wetlands of the Sacramento and San Joaquin Rivers through the San Francisco Bay/Delta Estuary to the Pacific Ocean (Fig. 1). Water quality concerns center on elevated selenium (Se) and salt concentrations in irrigation drainage water discharged into the waterways of the relatively arid San Joaquin Valley (SJV), including the San Joaquin River (SJR). These waters are made unique by dissolved Se, weathered from marine sedimentary rocks of the Coast Ranges to the west, being ultimately concentrated to toxic levels in aquatic wildlife in the wetlands of the SJV/SJR trough (Figs. 1 and 2) (Presser and Ohlendorf, 1987; Presser, 1994). Scientific and environmental concerns focus on the bioreactive properties of Se and its partitioning among biota, water, and sediment, and on whether simple dilution models can be applied to an element that bioaccumulates. Because of state and federal commitments to provide water for irrigation, as well as drainage of irriga­ tion wastewater by the year 2000 drainage from over 180,000 ha of seleniferous, salinized farmland within the western SJV will create approximately 387 million cubic meters of potentially toxic drainage water annually (i.e., “problem water,” as defined by the San Joaquin Valley Drainage Program, 1990), thus lending urgency to an understanding of the biogeochemistry of Se in this environment.

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USGS1995

Evidence of impaired reproduction by Western mosquitofish inhabiting seleniferous agricultural drainwater

Western mosquitofish Gambusia affinis from the San Luis Drain (SLD), a major conveyance system for seleniferous agricultural subsurface (tile) drainage water in the San Joaquin Valley, California, experienced lower reproductive success than did mosquitofish from a nearby reference area (Pond 26 at the Volta Wildlife Area, VOLTA) that had no history of receiving tile drainage. At birth, mean survival of SLD fry was 70% in 1984 and 77% in 1985, whereas mean survival of VOLTA fry was greater than 99% in 1984 and 97% in 1985. Measurements of total length (TL) of offspring born to SLD females in 1985 showed that stillborn fry (mean TL, 7.5 mm) were significantly shorter than live fry (mean TL, 9.4 mm). In addition, most stillborn fry were at earlier stages of development (contained prominent yolk sacs or occasionally resembled eyed embryos) than most live fry (yolk sacs were fully resorbed). In comparison, stillborn and live fry born to VOLTA females did not differ significantly in TL (mean for stillborn fry, 7.1 mm; mean for live fry, 7.5 mm), and nearly all fry had resorbed their yolk sacs. Mosquitofish from the SLD contained over 100 μg/g (whole‐body concentration in dry weight) of selenium, whereas those from VOLTA averaged 1.5 μg/g. Although experiments are still needed to establish cause and effect, the high incidence of abnormal births of mosquitofish from the SLD is seemingly a response to selenium toxicity.

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USGS1995

Effects of two contrasting agricultural land uses on shallow groundwater quality in the San Joaquin Valley, California; design and preliminary interpretation

From 1992 through 1994, the San Joaquin-Tulare Basins Study team of the USGS National Water Quality Assessment program investigated the occurrence and distribution of water quality constituents in shallow groundwater underlying two areas of different agricultural land uses: almond orchards and vineyards. The study was restricted to the alluvial fans of the eastern San Joaquin Valley, the area of most groundwater use in the valley. A geographic information system (GIS) was used to delineate the distribution of the two target land uses, to evaluate ancillary data, and to select candidate wells that fit prescribed criteria. Twenty domestic water supply wells were sampled in each of the two areas. In addition, pairs of observation wells were installed and sampled at five of the sites in each area to evaluate whether the water quality in the domestic wells reflects that of the shallow groundwater underlying the target land use. A preliminary evaluation of the results shows that nitrate concentrations in the shallow groundwater are significantly higher in the almond orchard areas than in the vineyard area (p=0.005). In contrast, concentrations of 1,2-dibromo-3-chloropropane (DBCP) were higher in the vineyard area than in the almond orchard area (p=0.032). The most frequently detected pesticides in groundwater underlying both areas were simazine, atrazine, and desethylatrazine (an atrazine degradation product). These observations are explained, in part, by differences in chemical application and hydrogeologic factors.

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USGS1995

Areal distribution of selected trace elements, salinity, and major ions in shallow ground water, Tulare Basin, Southern San Joaquin Valley, California

The distribution of salinity and selected trace elements in shallow ground water in the Tulare Basin, California, was assessed to evaluate potential problems related to disposal in evaporation ponds of irrigation drain water containing elevated concentrations of selenium and other trace elements. The constituents of primary concern were selenium, arsenic, and salinity; uranium, boron, and molybdenum also were evaluated. Samples from 117 shallow wells were analyzed, and the results for samples from 110 of the wells were interpreted in relation to surficial geology, sediment depositional environment, soil characteristics, and hydrologic processes to determine the geochemical and hydrologic factors affecting the distribution of these constituents in ground water. In general, shallow ground water in areas where concentrations of salinity and most trace elements are elevated is influenced primarily by sediments derived from marine sedimentary rocks originating in the Coast Range, San Emigdio Mountains, and Tehachapi Mountains, and probably by unusual exposures of similar marine formations in the Sierra Nevada. Ground water in areas where concentrations of salinity and trace elements are significantly lower generally is influenced by igneous and metamorphic rocks exposed in the Sierra Nevada. In addition to sources of sediments, evaporation of shallow ground water, as indicated by isotopic enrichment of oxygen-18 and deuterium, increases salinity and concentrations of conservative trace elements such as selenium (under oxidizing conditions) and boron. Redox conditions affect the oxidation state of all trace elements of concern, except boron, and were found to be a major influence on trace-element solubility. Under oxidized conditions, selenate predominates and behaves conservatively, and arsenate predominates and is affected by sorption reactions that can limit arsenic solubility. Under reduced conditions, selenium is reduced to insoluble elemental selenium and arsenite predominates and generally is more soluble than arsenate. Elevated concentrations of uranium in shallow ground water probably are associated with uranium deposits in Kern County and other parts of the basin where oxidized conditions cause the more soluble uranyl species to predominate. Boron was correlated with salinity and behaved conservatively, whereas adsorption and precipitation of molybdenum minerals probably limited molybdenum solubility. Interrelations among constituents were examined with principal component analysis. The first two principal components explained 50.7 percent of the variance in the data. The first principal component was related to salinity, and the second principal component was related to redox conditions, reflecting two of the major influences on shallow groundwater quality found in this study.

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USGS1992

Selenium and other elements in freshwater fishes from the irrigated San Joaquin valley, California

Arsenic (As), chromium (Cr), mercury (Hg), and selenium (Se) were measured in composite whole-body samples of five fishes — bluegill ( Lepomis macrochirus ), common carp ( Cyprinus carpio ), mosquitofish ( Gambusia affinis ), largemouth bass ( Micropterus salmoides ), and Sacramento blackfish ( Orthodon microlepidotus ) — from the San Joaquin River system to determine if concentrations were elevated from exposure to agricultural subsurface (tile) drainage. Except for Cr, the concentrations of these elements in fishes from one or more sites were elevated; however, only Se approached concentrations that may adversely affect survival, growth, or reproduction in warm water fishes. Moreover, only Se among the four measured elements exhibited a geographic (spatial) pattern that coincided with known inflows of tile drainage to the San Joaquin River and its tributaries. Historical data from the Grassland Water District (Grasslands; a region exposed to concentrated tile drainage) suggested that concentrations of Se in fishes were at maximum during or shortly after 1984 and have been slightly lower since then. The recent decline of Se concentrations in fishes from the Grasslands could be temporary if additional acreages of irrigated lands in this portion of the San Joaquin Valley must be tile-drained to protect agricultural crops from rising groundwater tables

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USGS1992

Toxicity of agricultural subsurface drainwater from the San Joaquin Valley, California to juvenile chinook salmon and striped bass

Juvenile chinook salmon Oncorhynchus tshawytscha (40-50 mm total length, TL) and striped bass Morone saxatilis (30-40 mm TL) were exposed to serial dilutions (100, 50, 25, and 12.5%) of agricultural subsurface drainwater (WWD), reconstituted drainwater (RWWD), and reconstituted seawater (IO). Agricultural subsurface drainwater contained naturally elevated concentrations of major ions (such as sodium and sulfate) and trace elements (especially boron and selenium), RWWD contained concentrations of major ions that mimicked those in WWD but trace elements were not elevated, and IO contained concentrations of total dissolved salt that were similar to those in WWD and RWWD but chloride replaced sulfate as the dominant anion. After 28 d of static exposure, over 75% of the chinook salmon in 100% WWD had died, whereas none had died in other dilutions and water types. Growth of chinook salmon in WWD and RWWD, but not in IO, exhibited dilution responses. All striped bass died in 100% WWD within 23 d, whereas 19 of 20 striped bass had died in 100% RWWD after 28 d. In contrast, none died in 100% IO. Growth of striped bass was impaired only in WWD. Fish in WWD accumulated as much as 200 μg/g (dry-weight basis) of boron, whereas fish in control water accumulated less than 3.1 μg/g. Although potentially toxic concentrations of selenium occurred in WWD (geometric means, 158-218 μg/L), chinook salmon and striped bass exposed to this water type accumulated 5.7 μg Se/g or less. These findings indicate that WWD was toxic to chinook salmon and striped bass. Judging from available data, the toxicity of WWD was due primarily to high concentrations of major ions present in atypical ratios, to high concentrations of sulfate, or to both. High concentrations of boron and selenium also may have contributed to the toxicity of WWD, but their effects were not clearly delineated.

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USGS1990

Selenium speciation methods and application to soil saturation extracts from San Joaquin Valley, California

Methods to determine soluble concentrations of selenite, selenate, and organic Se were evaluated on saturation extracts of soil samples collected from three sites on the Panoche Creek alluvial fan in the western San Joaquin Valley, California. The methods were used in combination with hydride-generation atomic-absorption spectrometry for detection of Se, and included a selective chemical-digestion method and three chromatographic methods using XAD-8 resin, Sep-Pak C 18 cartridge, and a combination of XAD-8 resin and activated charcoal. The chromatography methods isolate dissolved organic matter that can inhibit Se detection by hydride-generation atomic-absorption spectrometry. Isolation of hydrophobic organic matter with XAD-8 did not affect concentrations of selenite and selenate, and the isolated organic matter represents a minimal estimation of organic Se. Ninety-eight percent of the Se in the extracts was selenate and about 100% of the isolated organic Se was associated with the humic acid fraction of dissolved organic matter. The depth distribution of Se species in the soil saturation extracts support a hypothesis that the distribution of soluble Se and salinity in these soils is the result of evaporation from a shallow water table and leaching by irrigation water low in Se and salinity.

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USGS1990

Geochemical evidence for Se mobilization by the weathering of pyritic shale, San Joaquin Valley, California, U.S.A.

Acidic (pH 4) seeps issue from the weathered Upper Cretaceous-Paleocene marine sedimentary shales of the Moreno Formation in the semi-arid Coast Ranges of California. The chemistry of the acidic solutions is believed to be evidence of current reactions ultimately yielding hydrous sodium and magnesium sulfate salts, e.g. mirabilite and bloedite, from the oxidation of primary pyrite. The selenate form of Se is concentrated in these soluble salts, which act as temporary geological sinks. Theoretically, the open lattice structures of these hydrous minerals could incorporate the selenate (SeO 4 −2 ) anion in the sulfate (SO 4 −2 ) space. When coupled with a semi-arid to arid climate, fractional crystallization and evaporative concentration can occur creating a sodium-sulfate fluid that exceeds the U.S. Environmental Protection Agency limit of 1000 μg l −1 for a toxic Se waste. The oxidative alkaline conditions necessary to ensure the concentration of soluble selenate are provided in the accompanying marine sandstones of the Panoche and Lodo Formations and the eugeosynclinal Franciscan assemblage. Runoff and extensive mass wasting in the area reflect these processes and provide the mechanisms which transport Se to the farmlands of the west-central San Joaquin Valley. Subsurface drainage from these soils consequently transports Se to refuge areas in amounts elevated to cause a threat to wildlife.

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USGS1990

Evaluation of selenium mobility in soil using sorption experiments and a numerical model, western San Joaquin Valley, California

Sorption experiments and a numerical model were used to assess the effects of irrigation and drainage on the depth distribution of selenite and selenate in soils from the western San Joaquin Valley, California. The sorption studies show that selenate (15 to 12,400 micrograms per liter of selenium) is not adsorbed to soil, whereas selenite (10 to 5,000 micrograms per liter of selenium) is rapidly adsorbed. The time lag between adsorption and desorption is considerable, indicating nonreversible sorption, and an equation describing the desorption reaction is determined by the concentration of adsorbed selenite prior to desorption. A numerical model was used to qualitatively evaluate the nonreversible sorption reaction and its affect on selenite mobility during leaching by irrigation water. Model results show that selenite is resistant to leaching and therefore can represent a potential long-term source of selenium to ground water. In contrast, selenate behaves as a conservative constituent under alkaline and oxidized conditions and is easily leached from soil. Chemical analyses of soils from irrigated and non-irrigated sites confirm the experimental and modeling results. Increasing salinity and soluble concentrations of selenate at a site irrigated for more than 40 years indicated leaching and downward displacement by irrigation water. Decreasing salinity and soluble concentrations of selenate at a nonirrigated site probably resulted from evaporation from the shallow water table. Adsorbed selenium in the irrigated and nonirrigated soils is mostly selenite and has been minimally affected by irrigation and drainage.

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USGS1990

Ground-water flow and solute movement to drain laterals, western San Joaquin Valley, California; I, Geochemical assessment

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 of chemical and isotopic analysis of the samples and analysis of hydraulic-head data and drain-lateral flow data elucidate the process of mixing of deep and shallow ground water entering the drain laterals. The deep ground water was subject to partial evaporation prior to drainage-system installation and has been displaced downward (at depths greater than 6 meters) in the ground-water system. This ground water is flowing toward the drain laterals. The percentage of the deep, isotopically enriched ground water entering the drain laterals varies with time and between drain laterals. The percentage of the total drain-lateral flow, which is deep ground-water flow, is about 30 percent for the shallow drain lateral (1.8 meters below land surface) and 60 percent for the deep drain lateral (2.7 meters below land surface). During irrigation, the percentages decrease to 0 and 30 percent for the shallow and deep drain laterals, respectively. Selenium loads in the drain laterals vary with time and between drain laterals. The selenium load for the shallow drain lateral (68 kilograms) during 1 year is 21 percent of the load for the deep drain lateral (332 kilograms) because it collects less deep, high-selenium ground water and does not flow continuously. Although selenium concentrations in the drain-lateral water decreased during irrigation, selenium loads increased substantially during a preplant irrigation because of increased flow into the drain laterals. The selenium loads during 8 days of irrigation represented a substantial percentage (25 percent for the shallow drain lateral and 11 percent for the deep drain lateral) of the total selenium load for 1 year.

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USGS1990

Ground-water flow and solute movement to drain laterals, western San Joaquin Valley, California; II, Quantitative hydrologic assessment

Ground-water-flow modeling was used to estimate ground-water-flow paths and traveltimes to quantitatively assess the hydrologic processes affecting ground water and solute movement to drain laterals. Modeling results were used to calculate the depth distribution of ground water flowing into drain laterals at 1.8 meters (drain lateral 1) and 2.7 meters (drain lateral 2) below land surface. The simulations indicated that under nonirrigated conditions about 89 percent of the flow in drain lateral 2 was from ground water originating from depths greater than 6 meters below land surface. The deep ground water has higher selenium concentrations than shallow ground water. Simulation of irrigated conditions indicates that as recharge increases, the proportion of deep ground water entering the drain laterals decreases. Ground-water-flow modeling also was used to estimate selenium loads in drain laterals for varying drain-lateral flow rates. Simulated loads are in general agreement with measured loads and increase with increasing drain-lateral flow. Simulations further indicate ground water that contains high-selenium concentrations probably will continue to enter drain lateral 2 for more than 8 years.

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USGS1990

Calibration of a texture-based model of a ground-water flow system, western San Joaquin Valley, California

The occurrence of selenium in agricultural drain water from the western San Joaquin Valley, California, has focused concern on the semiconfined ground-water flow system, which is underlain by the Corcoran Clay Member of the Tulare Formation. A two-step procedure is used to calibrate a preliminary model of the system for the purpose of determining the steady-state hydraulic properties. Horizontal and vertical hydraulic conductivities are modeled as functions of the percentage of coarse sediment, hydraulic conductivities of coarse-textured (Keearse) and fine-textured (Kfine) end members, and averaging methods used to calculate equivalent hydraulic conductivities. The vertical conductivity of the Corcoran (Keen) is an additional parameter to be evaluated. In the first step of the calibration procedure, the model is run by systematically varying the following variables: (1) Kcoarse/Kfine' (2) KcoarsdKcorc' and (3) choice of averaging methods in the horizontal and vertical directions. Root mean square error and bias values calculated from the model results are functions of these variables. These measures of error provide a means for evaluating model sensitivity and for selecting values of Keearse, Kfine, and Kcorc for use in the second step of the calibration procedure. In the second step, recharge rates are evaluated as functions of Keearse, Kcere, and a combination of averaging methods. The associated Kfine values are selected so that the root mean square error is minimized on the basis of the results from the first step. The results of the two-step procedure indicate that the spatial distribution of hydraulic conductivity that best produces the measured hydraulic head distribution is created through the use of arithmetic averaging in the horizontal direction and either geometric or harmonic averaging in the vertical. The equivalent hydraulic conductivities resulting from either combination of averaging methods compare favorably to field- and laboratory-based values.

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