In Africa the variability of rainfall in space and time is high, and the general availability of historical gauge data is low. This makes many food security and hydrologic preparedness activities difficult. In order to help overcome this limitation, we have created the Collaborative Historical African Rainfall Model (CHARM). CHARM combines three sources of information: climatologically aided interpolated (CAI) rainfall grids (monthly/0.5° ), National Centers for Environmental Prediction reanalysis precipitation fields (daily/1.875° ) and orographic enhancement estimates (daily/0.1° ). The first set of weights scales the daily reanalysis precipitation fields to match the gridded CAI monthly rainfall time series. This produces data with a daily/0.5° resolution. A diagnostic model of orographic precipitation, VDELB—based on the dot-product of the surface wind V and terrain gradient (DEL) and atmospheric buoyancy B—is then used to estimate the precipitation enhancement produced by complex terrain. Although the data are produced on 0.1° grids to facilitate integration with satellite-based rainfall estimates, the ‘true’ resolution of the data will be less than this value, and varies with station density, topography, and precipitation dynamics. The CHARM is best suited, therefore, to applications that integrate rainfall or rainfall-driven model results over large regions.
\nThe CHARM time series is compared with three independent datasets: dekadal satellite-based rainfall estimates across the continent, dekadal interpolated gauge data in Mali, and daily interpolated gauge data in western Kenya. These comparisons suggest reasonable accuracies (standard errors of about half a standard deviation) when data are aggregated to regional scales, even at daily time steps. Thus constrained, numerical weather prediction precipitation fields do a reasonable job of representing large-scale diurnal variations.
\nThe mercury-gold deposits of the Ivanhoe mining district in northern Nevada formed when middle Miocene rhyolitic volcanism and high-angle faulting disrupted a shallow lacustrine environment. Sinter and replacement mercury deposits formed at and near the paleosurface, and disseminated gold deposits and high-grade gold-silver veins formed beneath the hot spring deposits. The lacustrine environment provided abundant meteoric water; the rhyolites heated the water; and the faults, flow units, and lakebeds provided fluid pathways for the hydrothermal fluids. A shallow lake began to develop in the Ivanhoe area about 16.5 Ma. The lake progressively expanded and covered the entire area with fine-grained lacustrine sediments. Lacustrine sedimentation continued to at least 14.4 Ma, and periodic fluctuations in the size and extent of the lake may have been responses to both climate and nearby volcanism. The eruption of rhyolite and andesite flows and domes periodically disrupted the lacustrine environment and produced interfingered flows and lake sediments. The major pulse of rhyolitic volcanism took place between 15.16 ± 0.05 and 14.92 ± 0.05 Ma. High-angle faulting began in the basement about 15.2 Ma, penetrated to and disrupted the paleosurface after 15.10 ± 0.06 Ma, and largely ceased by 14.92 ± 0.05 Ma. Ground motion related to both faulting and volcanism created debris flows and soft-sediment deformation in the lakebeds. Mercury-gold mineralization was coeval with rhyolite volcanism and high-angle faulting, and it took place about 15.2 to 14.9 Ma. At and near the paleosurface, hydrothermal fluids migrated through tuffaceous sediments above relatively impermeable volcanic and Paleozoic units, creating chalcedonic, cinnabar-bearing replacement bodies and sinters. Disseminated gold was deposited in sedimentary and volcanic rocks beneath the mercury deposits, although the hydrologic path between the two ore types is unclear. Higher-grade gold-silver deposits formed in massive rhyolites and Paleozoic quartzites at deeper levels, and these mineralized zones possibly represent the feeder zones for the higher-level deposits. Fluctuations in the ground-water table locally produced hydrothermal oxidation of the near-surface mercury and disseminated gold deposits. The locus of mineralization shifted with time, moving south and east from its inception point in the west-central part of the district. Thus, although mineralization in the district took place during a span of 300,000 years, the duration of mineralization at any one place probably was much shorter. The low-sulfidation deposits of the Ivanhoe district formed at the same time and under similar conditions as those in the nearby Midas district, 15 km to the northwest, which includes the large, high-grade Ken Snyder gold-silver epithermal vein deposit. The exposures in the Ivanhoe district are interpreted to represent the near-surface example of the paleosurface that originally was present above the Midas mineralizing system. The resulting combined Ivanhoe-Midas model provides an exploration guide for epithermal deposits in similar geologic environments in northern Nevada.
","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.98.2.409","issn":"03610128","usgsCitation":"Wallace, A.R., 2003, Geology of the Ivanhoe Hg-Au district, northern Nevada: Influence of Miocene volcanism, lakes, and active faulting on epithermal mineralization: Economic Geology, v. 98, no. 2, p. 409-424, https://doi.org/10.2113/gsecongeo.98.2.409.","productDescription":"16 p.","startPage":"409","endPage":"424","costCenters":[],"links":[{"id":387485,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"98","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a25cae4b0c8380cd58b8d","contributors":{"authors":[{"text":"Wallace, A. R.","contributorId":59445,"corporation":false,"usgs":true,"family":"Wallace","given":"A.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":406989,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70025850,"text":"70025850 - 2003 - Geomorphic and hydrologic assessment of erosion hazards at the Norman municipal landfill, Canadian River floodplain, central Oklahoma","interactions":[],"lastModifiedDate":"2018-11-16T10:21:33","indexId":"70025850","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1574,"text":"Environmental & Engineering Geoscience","printIssn":"1078-7275","active":true,"publicationSubtype":{"id":10}},"title":"Geomorphic and hydrologic assessment of erosion hazards at the Norman municipal landfill, Canadian River floodplain, central Oklahoma","docAbstract":"The Norman, Oklahoma, municipal landfill closed in 1985 after 63 years of operation, because it was identified as a point source of hazardous leachate composed of organic and inorganic compounds. The landfill is located on the floodplain of the Canadian River, a sand-bed river characterized by erodible channel boundaries and by large variation in mean monthly discharges. In 1986, floodwaters eroded riprap protection at the southern end of the landfill and penetrated the landfill's clay cap, thereby exposing the landfill contents. The impact of this moderate-magnitude flood event (Q12) was the catalyst to investigate erosion hazards at the Norman landfill. This geomorphic investigation analyzed floodplain geomorphology and historical channel changes, flood-frequency distributions, an erosion threshold, the geomorphic effectiveness of discharge events, and other factors that influence erosion hazards at the landfill site. The erosion hazard at the Norman landfill is a function of the location of the landfill with respect to the channel thalweg, erosional resistance of the channel margins, magnitude and duration of discrete discharge events, channel form and hydraulic geometry, and cumulative effects related to a series of discharge events. Based on current climatic conditions and historical channel changes, a minimum erosion threshold is set at bankfull discharge (Q = 572 m3/s). The annual probability of exceeding this threshold is 0.53. In addition, this analysis indicates that peak stream power is less informative than total energy expenditures when estimating the erosion potential or geomorphic effectiveness of discrete discharge events. On the Canadian River, long-duration, moderate-magnitude floods can have larger total energy expenditures than shorter-duration, high-magnitude floods and therefore represent the most serious erosion hazard to floodplain structures.
","language":"English","publisher":"Geological Society of America","doi":"10.2113/9.3.241","issn":"10787275","usgsCitation":"Curtis, J.A., and Whitney, J.W., 2003, Geomorphic and hydrologic assessment of erosion hazards at the Norman municipal landfill, Canadian River floodplain, central Oklahoma: Environmental & Engineering Geoscience, v. 9, no. 3, p. 241-252, https://doi.org/10.2113/9.3.241.","productDescription":"12 p.","startPage":"241","endPage":"252","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":234503,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208632,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.2113/9.3.241"}],"volume":"9","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a277de4b0c8380cd5992f","contributors":{"authors":[{"text":"Curtis, Jennifer A. 0000-0001-7766-994X jacurtis@usgs.gov","orcid":"https://orcid.org/0000-0001-7766-994X","contributorId":927,"corporation":false,"usgs":true,"family":"Curtis","given":"Jennifer","email":"jacurtis@usgs.gov","middleInitial":"A.","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":406816,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Whitney, John W. 0000-0003-3824-3692 jwhitney@usgs.gov","orcid":"https://orcid.org/0000-0003-3824-3692","contributorId":804,"corporation":false,"usgs":true,"family":"Whitney","given":"John","email":"jwhitney@usgs.gov","middleInitial":"W.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":true,"id":406815,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025847,"text":"70025847 - 2003 - The sedimentary record of climatic and anthropogenic influence on the Patuxent estuary and Chesapeake Bay ecosystems","interactions":[],"lastModifiedDate":"2012-03-12T17:20:32","indexId":"70025847","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1583,"text":"Estuaries","active":true,"publicationSubtype":{"id":10}},"title":"The sedimentary record of climatic and anthropogenic influence on the Patuxent estuary and Chesapeake Bay ecosystems","docAbstract":"Ecological and paleoecological studies from the Patuxent River mouth reveal dynamic variations in benthic ostracode assemblages over the past 600 years due to climatic and anthropogenic factors. Prior to the late 20th century, centennial-scale changes in species dominance were influenced by climatic and hydrological factors that primarily affected salinity and at times led to oxygen depletion. Decadal-scale droughts also occurred resulting in higher salinities and migration of ostracode species from the deep channel (Loxoconcha sp., Cytheromorpha newportensis) into shallower water along the flanks of the bay. During the 19th century the abundance of Leptocythere nikraveshae and Perissocytheridea brachyforma suggest increased turbidity and decreased salinity. Unprecedented changes in benthic ostracodes at the Patuxent mouth and in the deep channel of the bay occurred after the 1960s when Cytheromorpha curta became the dominant species, reflecting seasonal anoxia. The change in benthic assemblages coincided with the appearance of deformities in foraminifers. A combination of increased nitrate loading due to greater fertilizer use and increased freshwater flow explains this shift. A review of the geochemical and paleoecological evidence for dissolved oxygen indicates that seasonal oxygen depletion in the main channel of Chesapeake Bay varies over centennial and decadal timescales. Prior to 1700 AD, a relatively wet climate and high freshwater runoff led to oxygen depletion but rarely anoxia. Between 1700 and 1900, progressive eutrophication occurred related to land dearance and increased sedimentation, but this was superimposed on the oscillatory pattern of oxygen depletion most likely driven by climatological and hydrological factors. It also seems probable that the four- to five-fold increase in sedimentation due to agricultural and timber activity could have contributed to an increased natural nutrient load, likely fueling the early periods (1700-1900) of hypoxla prior to widespread fertilizer use. Twentieth-century anoxia worsened in the late 1930s-1940s and again around 1970, reaching unprecedented levels in the past few decades. Decadal and interannual variability in oxygen depletion even in the 20th century is still strongly influenced by climatic processes influencing precipitation and freshwater runoff.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Estuaries","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01608347","usgsCitation":"Cronin, T.M., and Vann, C., 2003, The sedimentary record of climatic and anthropogenic influence on the Patuxent estuary and Chesapeake Bay ecosystems: Estuaries, v. 26, no. 2 A, p. 196-209.","startPage":"196","endPage":"209","numberOfPages":"14","costCenters":[],"links":[{"id":235011,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"26","issue":"2 A","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb005e4b08c986b324b8c","contributors":{"authors":[{"text":"Cronin, T. M. 0000-0002-2643-0979","orcid":"https://orcid.org/0000-0002-2643-0979","contributorId":42613,"corporation":false,"usgs":true,"family":"Cronin","given":"T.","email":"","middleInitial":"M.","affiliations":[{"id":40020,"text":"Florence Bascom Geoscience Center","active":true,"usgs":true}],"preferred":false,"id":406807,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Vann, C.D.","contributorId":51951,"corporation":false,"usgs":true,"family":"Vann","given":"C.D.","email":"","affiliations":[],"preferred":false,"id":406808,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025768,"text":"70025768 - 2003 - Kinetic dissolution of carbonates and Mn oxides in acidic water: Measurement of in situ field rates and reactive transport modeling","interactions":[],"lastModifiedDate":"2018-11-16T10:59:56","indexId":"70025768","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":835,"text":"Applied Geochemistry","active":true,"publicationSubtype":{"id":10}},"title":"Kinetic dissolution of carbonates and Mn oxides in acidic water: Measurement of in situ field rates and reactive transport modeling","docAbstract":"The kinetics of carbonate and Mn oxide dissolution under acidic conditions were examined through the in situ exposure of pure phase samples to acidic ground water in Pinal Creek Basin, Arizona. The average long-term calculated in situ dissolution rates for calcite and dolomite were 1.65??10-7 and 3.64??10-10 mmol/(cm2 s), respectively, which were about 3 orders of magnitude slower than rates derived in laboratory experiments by other investigators. Application of both in situ and lab-derived calcite and dolomite dissolution rates to equilibrium reactive transport simulations of a column experiment did not improve the fit to measured outflow chemistry: at the spatial and temporal scales of the column experiment, the use of an equilibrium model adequately simulated carbonate dissolution in the column. Pyrolusite (MnO2) exposed to acidic ground water for 595 days increased slightly in weight despite thermodynamic conditions that favored dissolution. This result might be related to a recent finding by another investigator that the reductive dissolution of pyrolusite is accompanied by the precipitation of a mixed Mn-Fe oxide species. In PHREEQC reactive transport simulations, the incorporation of Mn kinetics improved the fit between observed and simulated behavior at the column and field scales, although the column-fitted rate for Mn-oxide dissolution was about 4 orders of magnitude greater than the field-fitted rate. Remaining differences between observed and simulated contaminant transport trends at the Pinal Creek site were likely related to factors other than the Mn oxide dissolution rate, such as the concentration of Fe oxide surface sites available for adsorption, the effects of competition among dissolved species for available surface sites, or reactions not included in the model.","language":"English","publisher":"Elsevier","doi":"10.1016/S0883-2927(03)00010-6","issn":"08832927","usgsCitation":"Brown, J.G., and Glynn, P.D., 2003, Kinetic dissolution of carbonates and Mn oxides in acidic water: Measurement of in situ field rates and reactive transport modeling: Applied Geochemistry, v. 18, no. 8, p. 1225-1239, https://doi.org/10.1016/S0883-2927(03)00010-6.","productDescription":"15 p.","startPage":"1225","endPage":"1239","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":235006,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208913,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0883-2927(03)00010-6"}],"volume":"18","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a40a6e4b0c8380cd64f1f","contributors":{"authors":[{"text":"Brown, J. G.","contributorId":28263,"corporation":false,"usgs":true,"family":"Brown","given":"J.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":406510,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Glynn, P. D.","contributorId":7008,"corporation":false,"usgs":true,"family":"Glynn","given":"P.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":406509,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025762,"text":"70025762 - 2003 - The site-scale saturated zone flow model for Yucca Mountain: Calibration of different conceptual models and their impact on flow paths","interactions":[],"lastModifiedDate":"2018-09-27T11:28:45","indexId":"70025762","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2233,"text":"Journal of Contaminant Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"The site-scale saturated zone flow model for Yucca Mountain: Calibration of different conceptual models and their impact on flow paths","docAbstract":"This paper presents several different conceptual models of the Large Hydraulic Gradient (LHG) region north of Yucca Mountain and describes the impact of those models on groundwater flow near the potential high-level repository site. The results are based on a numerical model of site-scale saturated zone beneath Yucca Mountain. This model is used for performance assessment predictions of radionuclide transport and to guide future data collection and modeling activities. The numerical model is calibrated by matching available water level measurements using parameter estimation techniques, along with more informal comparisons of the model to hydrologic and geochemical information. The model software (hydrologic simulation code FEHM and parameter estimation software PEST) and model setup allows for efficient calibration of multiple conceptual models. Until now, the Large Hydraulic Gradient has been simulated using a low-permeability, east–west oriented feature, even though direct evidence for this feature is lacking. In addition to this model, we investigate and calibrate three additional conceptual models of the Large Hydraulic Gradient, all of which are based on a presumed zone of hydrothermal chemical alteration north of Yucca Mountain. After examining the heads and permeabilities obtained from the calibrated models, we present particle pathways from the potential repository that record differences in the predicted groundwater flow regime. The results show that Large Hydraulic Gradient can be represented with the alternate conceptual models that include the hydrothermally altered zone. The predicted pathways are mildly sensitive to the choice of the conceptual model and more sensitive to the quality of calibration in the vicinity on the repository. These differences are most likely due to different degrees of fit of model to data, and do not represent important differences in hydrologic conditions for the different conceptual models.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0169-7722(02)00190-0","issn":"01697722","usgsCitation":"Zyvoloski, G., Kwicklis, E., Eddebbarh, A., Arnold, B., Faunt, C., and Robinson, B., 2003, The site-scale saturated zone flow model for Yucca Mountain: Calibration of different conceptual models and their impact on flow paths: Journal of Contaminant Hydrology, v. 62-63, p. 731-750, https://doi.org/10.1016/S0169-7722(02)00190-0.","productDescription":"20 p.","startPage":"731","endPage":"750","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":234901,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208848,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0169-7722(02)00190-0"}],"volume":"62-63","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb036e4b08c986b324cda","contributors":{"authors":[{"text":"Zyvoloski, G.","contributorId":51068,"corporation":false,"usgs":true,"family":"Zyvoloski","given":"G.","email":"","affiliations":[],"preferred":false,"id":406482,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kwicklis, E.","contributorId":69759,"corporation":false,"usgs":true,"family":"Kwicklis","given":"E.","affiliations":[],"preferred":false,"id":406484,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Eddebbarh, A.-A.","contributorId":101425,"corporation":false,"usgs":true,"family":"Eddebbarh","given":"A.-A.","email":"","affiliations":[],"preferred":false,"id":406486,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Arnold, B.","contributorId":32713,"corporation":false,"usgs":true,"family":"Arnold","given":"B.","email":"","affiliations":[],"preferred":false,"id":406481,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Faunt, C. 0000-0001-5659-7529","orcid":"https://orcid.org/0000-0001-5659-7529","contributorId":77714,"corporation":false,"usgs":true,"family":"Faunt","given":"C.","affiliations":[],"preferred":false,"id":406485,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Robinson, B.A.","contributorId":63035,"corporation":false,"usgs":true,"family":"Robinson","given":"B.A.","email":"","affiliations":[],"preferred":false,"id":406483,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70025736,"text":"70025736 - 2003 - The saturated zone at Yucca Mountain: An overview of the characterization and assessment of the saturated zone as a barrier to potential radionuclide migration","interactions":[],"lastModifiedDate":"2018-09-18T08:37:39","indexId":"70025736","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2233,"text":"Journal of Contaminant Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"The saturated zone at Yucca Mountain: An overview of the characterization and assessment of the saturated zone as a barrier to potential radionuclide migration","docAbstract":"The US Department of Energy is pursuing Yucca Mountain, Nevada, for the development of a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste, if the repository is able to meet applicable radiation protection standards established by the US Nuclear Regulatory Commission and the US Environmental Protection Agency (EPA). Effective performance of such a repository would rely on a number of natural and engineered barriers to isolate radioactive waste from the accessible environment. Groundwater beneath Yucca Mountain is the primary medium through which most radionuclides might move away from the potential repository. The saturated zone (SZ) system is expected to act as a natural barrier to this possible movement of radionuclides both by delaying their transport and by reducing their concentration before they reach the accessible environment. Information obtained from Yucca Mountain Site Characterization Project activities is used to estimate groundwater flow rates through the site-scale SZ flow and transport model area and to constrain general conceptual models of groundwater flow in the site-scale area. The site-scale conceptual model is a synthesis of what is known about flow and transport processes at the scale required for total system performance assessment of the site. This knowledge builds on and is consistent with knowledge that has accumulated at the regional scale but is more detailed because more data are available at the site-scale level. The mathematical basis of the site-scale model and the associated numerical approaches are designed to assist in quantifying the uncertainty in the permeability of rocks in the geologic framework model and to represent accurately the flow and transport processes included in the site-scale conceptual model. Confidence in the results of the mathematical model was obtained by comparing calculated to observed hydraulic heads, estimated to measured permeabilities, and lateral flow rates calculated by the site-scale model to those calculated by the regional-scale flow model. In addition, it was confirmed that the flow paths leaving the region of the potential repository are consistent with those inferred from gradients of measured head and those independently inferred from water-chemistry data. The general approach of the site-scale SZ flow and transport model analysis is to calculate unit breakthrough curves for radionuclides at the interface between the SZ and the biosphere using the three-dimensional site-scale SZ flow and transport model. Uncertainties are explicitly incorporated into the site-scale SZ flow and transport abstractions through key parameters and conceptual models. ?? 2002 Elsevier Science B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Contaminant Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0169-7722(02)00154-7","issn":"01697722","usgsCitation":"Eddebbarh, A., Zyvoloski, G., Robinson, B., Kwicklis, E., Reimus, P., Arnold, B., Corbet, T., Kuzio, S., and Faunt, C., 2003, The saturated zone at Yucca Mountain: An overview of the characterization and assessment of the saturated zone as a barrier to potential radionuclide migration: Journal of Contaminant Hydrology, v. 62-63, p. 477-493, https://doi.org/10.1016/S0169-7722(02)00154-7.","startPage":"477","endPage":"493","numberOfPages":"17","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":234532,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208649,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0169-7722(02)00154-7"}],"volume":"62-63","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bafb4e4b08c986b3249b1","contributors":{"authors":[{"text":"Eddebbarh, A.-A.","contributorId":101425,"corporation":false,"usgs":true,"family":"Eddebbarh","given":"A.-A.","email":"","affiliations":[],"preferred":false,"id":406378,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Zyvoloski, G.A.","contributorId":20123,"corporation":false,"usgs":true,"family":"Zyvoloski","given":"G.A.","email":"","affiliations":[],"preferred":false,"id":406370,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Robinson, B.A.","contributorId":63035,"corporation":false,"usgs":true,"family":"Robinson","given":"B.A.","email":"","affiliations":[],"preferred":false,"id":406372,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kwicklis, E. M.","contributorId":86377,"corporation":false,"usgs":true,"family":"Kwicklis","given":"E. M.","affiliations":[],"preferred":false,"id":406375,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Reimus, P.W.","contributorId":91266,"corporation":false,"usgs":true,"family":"Reimus","given":"P.W.","email":"","affiliations":[],"preferred":false,"id":406377,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Arnold, B.W.","contributorId":77335,"corporation":false,"usgs":true,"family":"Arnold","given":"B.W.","email":"","affiliations":[],"preferred":false,"id":406373,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Corbet, T.","contributorId":48361,"corporation":false,"usgs":true,"family":"Corbet","given":"T.","email":"","affiliations":[],"preferred":false,"id":406371,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Kuzio, S.P.","contributorId":86539,"corporation":false,"usgs":true,"family":"Kuzio","given":"S.P.","email":"","affiliations":[],"preferred":false,"id":406376,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Faunt, C. 0000-0001-5659-7529","orcid":"https://orcid.org/0000-0001-5659-7529","contributorId":77714,"corporation":false,"usgs":true,"family":"Faunt","given":"C.","affiliations":[],"preferred":false,"id":406374,"contributorType":{"id":1,"text":"Authors"},"rank":9}]}} ,{"id":70025674,"text":"70025674 - 2003 - Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada","interactions":[],"lastModifiedDate":"2012-03-12T17:20:22","indexId":"70025674","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2233,"text":"Journal of Contaminant Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada","docAbstract":"Low-temperature calcite and opal record the past seepage of water into open fractures and lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level radioactive waste repository. Systematic measurements of calcite and opal coatings in the Exploratory Studies Facility (ESF) tunnel at the proposed repository horizon are used to estimate the volume of calcite at each site of calcite and/or opal deposition. By estimating the volume of water required to precipitate the measured volumes of calcite in the unsaturated zone, seepage rates of 0.005 to 5 liters/year (l/year) are calculated at the median and 95th percentile of the measured volumes, respectively. These seepage rates are at the low end of the range of seepage rates from recent performance assessment (PA) calculations, confirming the conservative nature of the performance assessment. However, the distribution of the calcite and opal coatings indicate that a much larger fraction of the potential waste packages would be contacted by this seepage than is calculated in the performance assessment.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Contaminant Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0169-7722(02)00167-5","issn":"01697722","usgsCitation":"Marshall, B., Neymark, L., and Peterman, Z.E., 2003, Estimation of past seepage volumes from calcite distribution in the Topopah Spring Tuff, Yucca Mountain, Nevada: Journal of Contaminant Hydrology, v. 62-63, p. 237-247, https://doi.org/10.1016/S0169-7722(02)00167-5.","startPage":"237","endPage":"247","numberOfPages":"11","costCenters":[],"links":[{"id":208739,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0169-7722(02)00167-5"},{"id":234705,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"62-63","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0b9de4b0c8380cd527d4","contributors":{"authors":[{"text":"Marshall, B.D.","contributorId":19581,"corporation":false,"usgs":true,"family":"Marshall","given":"B.D.","email":"","affiliations":[],"preferred":false,"id":406121,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Neymark, L.A. 0000-0003-4190-0278","orcid":"https://orcid.org/0000-0003-4190-0278","contributorId":56673,"corporation":false,"usgs":true,"family":"Neymark","given":"L.A.","affiliations":[],"preferred":false,"id":406122,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Peterman, Z. E.","contributorId":63781,"corporation":false,"usgs":true,"family":"Peterman","given":"Z.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":406123,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70025671,"text":"70025671 - 2003 - Chlorine-36 data at Yucca Mountain: Statistical tests of conceptual models for unsaturated-zone flow","interactions":[],"lastModifiedDate":"2012-03-12T17:20:22","indexId":"70025671","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2233,"text":"Journal of Contaminant Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"Chlorine-36 data at Yucca Mountain: Statistical tests of conceptual models for unsaturated-zone flow","docAbstract":"An extensive set of chlorine-36 (36Cl) data has been collected in the Exploratory Studies Facility (ESF), an 8-km-long tunnel at Yucca Mountain, Nevada, for the purpose of developing and testing conceptual models of flow and transport in the unsaturated zone (UZ) at this site. At several locations, the measured values of 36Cl/Cl ratios for salts leached from rock samples are high enough to provide strong evidence that at least a small component of bomb-pulse 36Cl, fallout from atmospheric testing of nuclear devices in the 1950s and 1960s, was measured, implying that some fraction of the water traveled from the ground surface through 200-300 m of unsaturated rock to the level of the ESF during the last 50 years. These data are analyzed here using a formal statistical approach based on log-linear models to evaluate alternative conceptual models for the distribution of such fast flow paths. The most significant determinant of the presence of bomb-pulse 36Cl in a sample from the welded Topopah Spring unit (TSw) is the structural setting from which the sample was collected. Our analysis generally supports the conceptual model that a fault that cuts through the nonwelded Paintbrush tuff unit (PTn) that overlies the TSw is required in order for bomb-pulse 36Cl to be transmitted to the sample depth in less than 50 years. Away from PTn-cutting faults, the ages of water samples at the ESF appear to be a strong function of the thickness of the nonwelded tuff between the ground surface and the ESF, due to slow matrix flow in that unit. ?? 2002 Elsevier Science B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Contaminant Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0169-7722(02)00176-6","issn":"01697722","usgsCitation":"Campbell, K., Wolfsberg, A., Fabryka-Martin, J., and Sweetkind, D., 2003, Chlorine-36 data at Yucca Mountain: Statistical tests of conceptual models for unsaturated-zone flow: Journal of Contaminant Hydrology, v. 62-63, p. 43-61, https://doi.org/10.1016/S0169-7722(02)00176-6.","startPage":"43","endPage":"61","numberOfPages":"19","costCenters":[],"links":[{"id":208716,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0169-7722(02)00176-6"},{"id":234669,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"62-63","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f5cde4b0c8380cd4c423","contributors":{"authors":[{"text":"Campbell, K.","contributorId":10526,"corporation":false,"usgs":true,"family":"Campbell","given":"K.","affiliations":[],"preferred":false,"id":406111,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Wolfsberg, A.","contributorId":106291,"corporation":false,"usgs":true,"family":"Wolfsberg","given":"A.","affiliations":[],"preferred":false,"id":406114,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Fabryka-Martin, J.","contributorId":51467,"corporation":false,"usgs":true,"family":"Fabryka-Martin","given":"J.","affiliations":[],"preferred":false,"id":406112,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Sweetkind, D.","contributorId":83645,"corporation":false,"usgs":true,"family":"Sweetkind","given":"D.","affiliations":[],"preferred":false,"id":406113,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70025666,"text":"70025666 - 2003 - Application of geographic information systems and remote sensing for quantifying patterns of erosion and water quality","interactions":[],"lastModifiedDate":"2012-03-12T17:20:22","indexId":"70025666","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Application of geographic information systems and remote sensing for quantifying patterns of erosion and water quality","docAbstract":"[No abstract available]","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrological Processes","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1002/hyp.1167","issn":"08856087","usgsCitation":"Ritchie, J., Walling, D., and Peters, J., 2003, Application of geographic information systems and remote sensing for quantifying patterns of erosion and water quality: Hydrological Processes, v. 17, no. 5, p. 885-886, https://doi.org/10.1002/hyp.1167.","startPage":"885","endPage":"886","numberOfPages":"2","costCenters":[],"links":[{"id":208646,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.1167"},{"id":234529,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"17","issue":"5","noUsgsAuthors":false,"publicationDate":"2003-03-14","publicationStatus":"PW","scienceBaseUri":"5059ec9ee4b0c8380cd493af","contributors":{"authors":[{"text":"Ritchie, J.C.","contributorId":89299,"corporation":false,"usgs":true,"family":"Ritchie","given":"J.C.","email":"","affiliations":[],"preferred":false,"id":406091,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Walling, D.E.","contributorId":24481,"corporation":false,"usgs":true,"family":"Walling","given":"D.E.","email":"","affiliations":[],"preferred":false,"id":406089,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Peters, J.","contributorId":58066,"corporation":false,"usgs":true,"family":"Peters","given":"J.","affiliations":[],"preferred":false,"id":406090,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70024612,"text":"70024612 - 2003 - Vegetation, soil, and flooding relationships in a blackwater floodplain forest","interactions":[],"lastModifiedDate":"2012-03-12T17:20:06","indexId":"70024612","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3750,"text":"Wetlands","onlineIssn":"1943-6246","printIssn":"0277-5212","active":true,"publicationSubtype":{"id":10}},"title":"Vegetation, soil, and flooding relationships in a blackwater floodplain forest","docAbstract":"Hydroperiod is considered the primary determinant of plant species distribution in temperate floodplain forests, but most studies have focused on alluvial (sediment-laden) river systems. Few studies have evaluated plant community relationships in blackwater river systems of the South Atlantic Coastal Plain of North America. In this study, we characterized the soils, hydroperiod, and vegetation communities and evaluated relationships between the physical and chemical environment and plant community structure on the floodplain of the Coosawhatchie River, a blackwater river in South Carolina, USA. The soils were similar to previous descriptions of blackwater floodplain soils but had greater soil N and P availability, substantially greater clay content, and lower soil silt content than was previously reported for other blackwater river floodplains. Results of a cluster analysis showed there were five forest communities on the site, and both short-term (4 years) and long-term (50 years) flooding records documented a flooding gradient: water tupelo community > swamp tupelo > laurel oak = overcup oak > mixed oak. The long-term hydrologic record showed that the floodplain has flooded less frequently from 1994 to present than in previous decades. Detrended correspondence analysis of environmental and relative basal area values showed that 27% of the variation in overstory community structure could be explained by the first two axes; however, fitting the species distributions to the DCA axes using Gaussian regression explained 67% of the variation. Axes were correlated with elevation (flooding intensity) and soil characteristics related to rooting volume and cation nutrient availability. Our study suggests that flooding is the major factor affecting community structure, but soil characteristics also may be factors in community structure in blackwater systems. ?? 2003, The Society of Wetland Scientists.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Wetlands","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"02775212","usgsCitation":"Burke, M., King, S., Gartner, D., and Eisenbies, M., 2003, Vegetation, soil, and flooding relationships in a blackwater floodplain forest: Wetlands, v. 23, no. 4, p. 988-1002.","startPage":"988","endPage":"1002","numberOfPages":"15","costCenters":[],"links":[{"id":233199,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bc1eae4b08c986b32a80a","contributors":{"authors":[{"text":"Burke, M.K.","contributorId":87248,"corporation":false,"usgs":true,"family":"Burke","given":"M.K.","email":"","affiliations":[],"preferred":false,"id":401905,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"King, S.L.","contributorId":105663,"corporation":false,"usgs":true,"family":"King","given":"S.L.","email":"","affiliations":[],"preferred":false,"id":401907,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Gartner, D.","contributorId":87249,"corporation":false,"usgs":true,"family":"Gartner","given":"D.","email":"","affiliations":[],"preferred":false,"id":401906,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Eisenbies, M.H.","contributorId":82420,"corporation":false,"usgs":true,"family":"Eisenbies","given":"M.H.","affiliations":[],"preferred":false,"id":401904,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70025642,"text":"70025642 - 2003 - The role of microbial reductive dechlorination of TCE at a phytoremediation site","interactions":[],"lastModifiedDate":"2020-01-05T14:44:38","indexId":"70025642","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2064,"text":"International Journal of Phytoremediation","active":true,"publicationSubtype":{"id":10}},"title":"The role of microbial reductive dechlorination of TCE at a phytoremediation site","docAbstract":"In April 1996, a phytoremediation field demonstration site at the Naval Air Station, Fort Worth, Texas, was developed to remediate shallow oxic ground water (<3.7 m deep) contaminated with chlorinated ethenes. Microbial populations were sampled in February and June 1998. The populations under the newly planted cottonwood trees had not yet matured to an anaerobic community that could dechlorinate trichloroethene (TCE) to cis-1,2-dichloroethene (DCE); however, the microbial population under a mature (∼22-year-old) cottonwood tree about 30 m southwest of the plantings had a mature anaerobic population capable of dechlorinating TCE to DCE, and DCE to vinyl chloride (VC). Oxygen-free sediment incubations with contaminated groundwater also demonstrated that resident microorganisms were capable of the dechlorination of TCE to DCE. This suggests that a sufficient amount of organic material is present for microbial dechlorination in aquifer microniches where dissolved O2 concentrations are low. Phenol, benzoic acid, acetic acid, and a cyclic hydrocarbon, compounds consistent with the degradation of root exudates and complex aromatic compounds, were identified by gas chromatography/mass spectrometry (GC/MS) in sediment samples under the mature cottonwood tree. Elsewhere at the site, transpiration and degradation by the cottonwood trees appears to be responsible for loss of chlorinated ethenes.
Concentrations of total lead as high as 1,600 μg/L were detected in gasoline-contaminated and uncontaminated groundwater at three gasoline-release sites in South Carolina. Total lead concentrations were highest in turbid groundwater samples from gasoline-contaminated and uncontaminated wells, whereas lower turbidity groundwater samples (collected using low-flow methods) had lower total lead concentrations. Dissolved lead concentrations in all wells sampled, however, were less than 15 μg total lead/L, the current United States Environmental Protection Agency (US EPA) maximum contaminant level (MCL). Because many total lead concentrations exceeded the MCL, the source of lead to the groundwater system at two of the three sites was investigated using a stable lead isotope ratio approach. Plots of the stable isotope ratios of lead (Pb) in groundwater as 207Pb/206Pb versus 208Pb/206Pb, and 208Pb/204Pb versus 206Pb/204Pb were similar to ratios characteristic of lead-based minerals in local rocks of the southeastern US, and were not similar to the stable lead isotopes ratios characteristic of distant lead ore deposits such as Broken Hill, Australia, used to produce tetraethyl lead in gasoline products prior to its phase-out and ban in the United States. Moreover, the isotopic composition of dissolved lead was equivalent to the isotopic composition of total lead in turbid samples collected from the same well, suggesting that the majority of the lead detected in the groundwater samples was associated with sediment particulates of indigenous aquifer material, rather than lead associated with spilled leaded gasoline. The results of this investigation indicate that (1) lead detected at some gasoline-release sites may be derived from the local aquifer material, rather than the gasoline release, and consequently may affect site-specific remediation goals; (2) non-low flow groundwater sampling methods, such as a disposable bailer, may result in turbid groundwater samples and high total lead concentrations, and; (3) stable lead isotopes can be used to clarify the source of lead detected above permissible levels in gasoline-contaminated groundwater systems.
","language":"English","publisher":"Springer","doi":"10.1007/s00254-003-0863-5","issn":"09430105","usgsCitation":"Landmeyer, J., Bradley, P., and Bullen, T., 2003, Stable lead isotopes reveal a natural source of high lead concentrations to gasoline-contaminated groundwater: Environmental Geology, v. 45, no. 1, p. 12-22, https://doi.org/10.1007/s00254-003-0863-5.","productDescription":"11 p.","startPage":"12","endPage":"22","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232918,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207738,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s00254-003-0863-5"}],"volume":"45","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9687e4b08c986b31b578","contributors":{"authors":[{"text":"Landmeyer, J. E.","contributorId":91140,"corporation":false,"usgs":true,"family":"Landmeyer","given":"J. E.","affiliations":[],"preferred":false,"id":402145,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bradley, P. M. 0000-0001-7522-8606","orcid":"https://orcid.org/0000-0001-7522-8606","contributorId":29465,"corporation":false,"usgs":true,"family":"Bradley","given":"P. M.","affiliations":[],"preferred":false,"id":402143,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bullen, T.D.","contributorId":79911,"corporation":false,"usgs":true,"family":"Bullen","given":"T.D.","email":"","affiliations":[],"preferred":false,"id":402144,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70024699,"text":"70024699 - 2003 - Mass load estimation errors utilizing grab sampling strategies in a karst watershed","interactions":[],"lastModifiedDate":"2021-08-21T18:18:32.700036","indexId":"70024699","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2529,"text":"Journal of the American Water Resources Association","active":true,"publicationSubtype":{"id":10}},"title":"Mass load estimation errors utilizing grab sampling strategies in a karst watershed","docAbstract":"Developing a mass load estimation method appropriate for a given stream and constituent is difficult due to inconsistencies in hydrologic and constituent characteristics. The difficulty may be increased in flashy flow conditions such as karst. Many projects undertaken are constrained by budget and manpower and do not have the luxury of sophisticated sampling strategies. The objectives of this study were to: (1) examine two grab sampling strategies with varying sampling intervals and determine the error in mass load estimates, and (2) determine the error that can be expected when a grab sample is collected at a time of day when the diurnal variation is most divergent from the daily mean. Results show grab sampling with continuous flow to be a viable data collection method for estimating mass load in the study watershed. Comparing weekly, biweekly, and monthly grab sampling, monthly sampling produces the best results with this method. However, the time of day the sample is collected is important. Failure to account for diurnal variability when collecting a grab sample may produce unacceptable error in mass load estimates. The best time to collect a sample is when the diurnal cycle is nearest the daily mean.
","language":"English","publisher":"Wiley","doi":"10.1111/j.1752-1688.2003.tb04423.x","issn":"1093474X","usgsCitation":"Fogle, A., Taraba, J., and Dinger, J., 2003, Mass load estimation errors utilizing grab sampling strategies in a karst watershed: Journal of the American Water Resources Association, v. 39, no. 6, p. 1361-1372, https://doi.org/10.1111/j.1752-1688.2003.tb04423.x.","productDescription":"12 p.","startPage":"1361","endPage":"1372","costCenters":[],"links":[{"id":388291,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"6","noUsgsAuthors":false,"publicationDate":"2007-06-08","publicationStatus":"PW","scienceBaseUri":"505a524ee4b0c8380cd6c2fe","contributors":{"authors":[{"text":"Fogle, A.W.","contributorId":96051,"corporation":false,"usgs":true,"family":"Fogle","given":"A.W.","email":"","affiliations":[],"preferred":false,"id":402321,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Taraba, J.L.","contributorId":51062,"corporation":false,"usgs":true,"family":"Taraba","given":"J.L.","email":"","affiliations":[],"preferred":false,"id":402319,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Dinger, J.S.","contributorId":64416,"corporation":false,"usgs":true,"family":"Dinger","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":402320,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70024703,"text":"70024703 - 2003 - Automated calibration of a stream solute transport model: Implications for interpretation of biogeochemical parameters","interactions":[],"lastModifiedDate":"2018-11-16T08:57:01","indexId":"70024703","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2564,"text":"Journal of the North American Benthological Society","onlineIssn":"1937-237X","printIssn":"0887-3593","active":true,"publicationSubtype":{"id":10}},"title":"Automated calibration of a stream solute transport model: Implications for interpretation of biogeochemical parameters","docAbstract":"The hydrologic processes of advection, dispersion, and transient storage are the primary physical mechanisms affecting solute transport in streams. The estimation of parameters for a conservative solute transport model is an essential step to characterize transient storage and other physical features that cannot be directly measured, and often is a preliminary step in the study of reactive solutes. Our study used inverse modeling to estimate parameters of the transient storage model OTIS (One dimensional Transport with Inflow and Storage). Observations from a tracer injection experiment performed on Uvas Creek, California, USA, are used to illustrate the application of automated solute transport model calibration to conservative and nonconservative stream solute transport. A computer code for universal inverse modeling (UCODE) is used for the calibrations. Results of this procedure are compared with a previous study that used a trial-and-error parameter estimation approach. The results demonstrated 1) importance of the proper estimation of discharge and lateral inflow within the stream system; 2) that although the fit of the observations is not much better when transient storage is invoked, a more randomly distributed set of residuals resulted (suggesting non-systematic error), indicating that transient storage is occurring; 3) that inclusion of transient storage for a reactive solute (Sr2+) provided a better fit to the observations, highlighting the importance of robust model parameterization; and 4) that applying an automated calibration inverse modeling estimation approach resulted in a comprehensive understanding of the model results and the limitation of input data.","language":"English","publisher":"University of Chicago Press","doi":"10.2307/1468348","issn":"08873593","usgsCitation":"Scott, D., Gooseff, M., Bencala, K., and Runkel, R., 2003, Automated calibration of a stream solute transport model: Implications for interpretation of biogeochemical parameters: Journal of the North American Benthological Society, v. 22, no. 4, p. 492-510, https://doi.org/10.2307/1468348.","productDescription":"19 p.","startPage":"492","endPage":"510","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232988,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059eef2e4b0c8380cd4a05f","contributors":{"authors":[{"text":"Scott, D.T.","contributorId":44324,"corporation":false,"usgs":true,"family":"Scott","given":"D.T.","email":"","affiliations":[],"preferred":false,"id":402330,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gooseff, M.N.","contributorId":21668,"corporation":false,"usgs":true,"family":"Gooseff","given":"M.N.","email":"","affiliations":[],"preferred":false,"id":402329,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bencala, K.E.","contributorId":105312,"corporation":false,"usgs":true,"family":"Bencala","given":"K.E.","email":"","affiliations":[],"preferred":false,"id":402332,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Runkel, R.L.","contributorId":97529,"corporation":false,"usgs":true,"family":"Runkel","given":"R.L.","affiliations":[],"preferred":false,"id":402331,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70025601,"text":"70025601 - 2003 - Molecular-scale characterization of uranium sorption by bone apatite materials for a permeable reactive barrier demonstration","interactions":[],"lastModifiedDate":"2018-11-16T08:10:13","indexId":"70025601","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1565,"text":"Environmental Science & Technology","onlineIssn":"1520-5851","printIssn":"0013-936X","active":true,"publicationSubtype":{"id":10}},"title":"Molecular-scale characterization of uranium sorption by bone apatite materials for a permeable reactive barrier demonstration","docAbstract":"Uranium binding to bone charcoal and bone meal apatite materials was investigated using U LIII-edge EXAFS spectroscopy and synchrotron source XRD measurements of laboratory batch preparations in the absence and presence of dissolved carbonate. Pelletized bone char apatite recovered from a permeable reactive barrier (PRB) at Fry Canyon, UT, was also studied. EXAFS analyses indicate that U(VI) sorption in the absence of dissolved carbonate occurred by surface complexation of U(VI) for sorbed concentrations ≤ 5500 μg U(VI)/g for all materials with the exception of crushed bone char pellets. Either a split or a disordered equatorial oxygen shell was observed, consistent with complexation of uranyl by the apatite surface. A second shell of atoms at a distance of 2.9 Å was required to fit the spectra of samples prepared in the presence of dissolved carbonate (4.8 mM total) and is interpreted as formation of ternary carbonate complexes with sorbed U(VI). A U−P distance at 3.5−3.6 Å was found for most samples under conditions where uranyl phosphate phases did not form, which is consistent with monodentate coordination of uranyl by phosphate groups in the apatite surface. At sorbed concentrations ≥ 5500 μg U(VI)/g in the absence of dissolved carbonate, formation of the uranyl phosphate solid phase, chernikovite, was observed. The presence of dissolved carbonate (4.8 mM total) suppressed the formation of chernikovite, which was not detected even with sorbed U(VI) up to 12 300 μg U(VI)/g in batch samples of bone meal, bone charcoal, and reagent-grade hydroxyapatite. EXAFS spectra of bone char samples recovered from the Fry Canyon PRB were comparable to laboratory samples in the presence of dissolved carbonate where U(VI) sorption occurred by surface complexation. Our findings demonstrate that uranium uptake by bone apatite will probably occur by surface complexation instead of precipitation of uranyl phosphate phases under the groundwater conditions found at many U-contaminated sites.
Analysis of a 72-h, constant-rate aquifer test conducted in a coarse-grained and highly permeable, glacial outwash deposit on Cape Cod, Massachusetts revealed that drawdowns measured in 20 piezometers located at various depths below the water table and distances from the pumped well were significantly influenced by effects of drainage from the vadose zone. The influence was greatest in piezometers located close to the water table and diminished with increasing depth. The influence of the vadose zone was evident from a gap, in the intermediate-time zone, between measured drawdowns and drawdowns computed under the assumption that drainage from the vadose zone occurred instantaneously in response to a decline in the elevation of the water table. By means of an analytical model that was designed to account for time-varying drainage, simulated drawdowns could be closely fitted to measured drawdowns regardless of the piezometer locations. Because of the exceptional quality and quantity of the data and the relatively small aquifer heterogeneity, it was possible by inverse modeling to estimate all relevant aquifer parameters and a set of three empirical constants used in the upper-boundary condition to account for the dynamic drainage process. The empirical constants were used to define a one-dimensional (1D) drainage versus time curve that is assumed to be representative of the bulk material overlying the water table. The curve was inverted with a parameter estimation algorithm and a 1D numerical model for variably saturated flow to obtain soil-moisture retention curves and unsaturated hydraulic conductivity relationships defined by the Brooks and Corey equations. Direct analysis of the aquifer-test data using a parameter estimation algorithm and a two-dimensional, axisymmetric numerical model for variably saturated flow yielded similar soil-moisture characteristics. Results suggest that hectare-scale soil-moisture characteristics are different from core-scale predictions and even relatively small amounts of fine-grained material and heterogeneity can dominate the large-scale soil-moisture characteristics and aquifer response.
Conditional distribution coefficients (KDOM‘) for Hg(II) binding to seven dissolved organic matter (DOM) isolates were measured at environmentally relevant ratios of Hg(II) to DOM. The results show that KDOM‘ values for different types of samples (humic acids, fulvic acids, hydrophobic acids) isolated from diverse aquatic environments were all within 1 order of magnitude (1022.5±1.0−1023.5±1.0 L kg-1), suggesting similar Hg(II) binding environments, presumably involving thiol groups, for the different isolates. KDOM‘ values decreased at low pHs (4) compared to values at pH 7, indicating proton competition for the strong Hg(II) binding sites. Chemical modeling of Hg(II)−DOM binding at different pH values was consistent with bidentate binding of Hg(II) by one thiol group (pKa = 10.3) and one other group (pKa = 6.3) in the DOM, which is in agreement with recent results on the structure of Hg(II)−DOM bonds obtained by extended X-ray absorption fine structure spectroscopy (EXAFS).
An in‐stream injection of two dissolved organic acids (phthalic and aspartic acids) was performed in an acidic mountain stream to assess the effects of organic acids on Fe photoreduction and H2O2 cycling. Results indicate that the fate of Fe is dependent on a net balance of oxidative and reductive processes, which can vary over a distance of several meters due to changes in incident light and other factors. Solution phase photoreduction rates were high in sunlit reaches and were enhanced by the organic acid addition but were also limited by the amount of ferric iron present in the water column. Fe oxide photoreduction from the streambed and colloids within the water column resulted in an increase in the diurnal load of total filterable Fe within the experimental reach, which also responded to increases in light and organic acids. Our results also suggest that Fe(II) oxidation increased in response to the organic acids, with the result of offsetting the increase in Fe(II) from photoreductive processes. Fe(II) was rapidly oxidized to Fe(III) after sunset and during the day within a well‐shaded reach, presumably through microbial oxidation. H2O2, a product of dissolved organic matter photolysis, increased downstream to maximum concentrations of 0.25 μM midday. Kinetic calculations show that the buildup of H2O2 is controlled by reaction with Fe(II), but this has only a small effect on Fe(II) because of the small formation rates of H2O2 compared to those of Fe(II). The results demonstrate the importance of incorporating the effects of light and dissolved organic carbon into Fe reactive transport models to further our understanding of the fate of Fe in streams and lakes.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/2002WR001768","usgsCitation":"Scott, D.T., Runkel, R.L., McKnight, D.M., Voelker, B.M., Kimball, B.A., and Carraway, E.R., 2003, Transport and cycling of iron and hydrogen peroxide in a freshwater stream: Influence of organic acids: Water Resources Research, v. 39, no. 11, p. 1-14, https://doi.org/10.1029/2002WR001768.","productDescription":"Article 1308; 14 p.","startPage":"1","endPage":"14","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":478533,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/2002wr001768","text":"Publisher Index Page"},{"id":233003,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb737e4b08c986b327112","contributors":{"authors":[{"text":"Scott, Durelle T.","contributorId":102383,"corporation":false,"usgs":true,"family":"Scott","given":"Durelle","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":403008,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Runkel, Robert L. 0000-0003-3220-481X runkel@usgs.gov","orcid":"https://orcid.org/0000-0003-3220-481X","contributorId":685,"corporation":false,"usgs":true,"family":"Runkel","given":"Robert","email":"runkel@usgs.gov","middleInitial":"L.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":403012,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"McKnight, Diane M.","contributorId":59773,"corporation":false,"usgs":false,"family":"McKnight","given":"Diane","email":"","middleInitial":"M.","affiliations":[{"id":16833,"text":"INSTAAR, University of Colorado","active":true,"usgs":false}],"preferred":false,"id":403009,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Voelker, Bettina M.","contributorId":74914,"corporation":false,"usgs":false,"family":"Voelker","given":"Bettina","email":"","middleInitial":"M.","affiliations":[{"id":12444,"text":"Massachusetts Institute of Technology","active":true,"usgs":false}],"preferred":false,"id":403010,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Kimball, Briant A. bkimball@usgs.gov","contributorId":533,"corporation":false,"usgs":true,"family":"Kimball","given":"Briant","email":"bkimball@usgs.gov","middleInitial":"A.","affiliations":[{"id":610,"text":"Utah Water Science Center","active":true,"usgs":true}],"preferred":true,"id":403011,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Carraway, Elizabeth R.","contributorId":30000,"corporation":false,"usgs":false,"family":"Carraway","given":"Elizabeth","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":403007,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70024887,"text":"70024887 - 2003 - Use of statistically and dynamically downscaled atmospheric model output for hydrologic simulations in three mountainous basins in the western United States","interactions":[],"lastModifiedDate":"2012-03-12T17:20:05","indexId":"70024887","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2342,"text":"Journal of Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"Use of statistically and dynamically downscaled atmospheric model output for hydrologic simulations in three mountainous basins in the western United States","docAbstract":"This paper examines the hydrologic model performance in three snowmelt-dominated basins in the western United States to dynamically- and statistically downscaled output from the National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis (NCEP). Runoff produced using a distributed hydrologic model is compared using daily precipitation and maximum and minimum temperature timeseries derived from the following sources: (1) NCEP output (horizontal grid spacing of approximately 210 km); (2) dynamically downscaled (DDS) NCEP output using a Regional Climate Model (RegCM2, horizontal grid spacing of approximately 52 km); (3) statistically downscaled (SDS) NCEP output; (4) spatially averaged measured data used to calibrate the hydrologic model (Best-Sta) and (5) spatially averaged measured data derived from stations located within the area of the RegCM2 model output used for each basin, but excluding Best-Sta set (All-Sta). In all three basins the SDS-based simulations of daily runoff were as good as runoff produced using the Best-Sta timeseries. The NCEP, DDS, and All-Sta timeseries were able to capture the gross aspects of the seasonal cycles of precipitation and temperature. However, in all three basins, the NCEP-, DDS-, and All-Sta-based simulations of runoff showed little skill on a daily basis. When the precipitation and temperature biases were corrected in the NCEP, DDS, and All-Sta timeseries, the accuracy of the daily runoff simulations improved dramatically, but, with the exception of the bias-corrected All-Sta data set, these simulations were never as accurate as the SDS-based simulations. This need for a bias correction may be somewhat troubling, but in the case of the large station-timeseries (All-Sta), the bias correction did indeed 'correct' for the change in scale. It is unknown if bias corrections to model output will be valid in a future climate. Future work is warranted to identify the causes for (and removal of) systematic biases in DDS simulations, and improve DDS simulations of daily variability in local climate. Until then, SDS based simulations of runoff appear to be the safer downscaling choice.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0022-1694(03)00252-X","issn":"00221694","usgsCitation":"Hay, L., and Clark, M., 2003, Use of statistically and dynamically downscaled atmospheric model output for hydrologic simulations in three mountainous basins in the western United States: Journal of Hydrology, v. 282, no. 1-4, p. 56-75, https://doi.org/10.1016/S0022-1694(03)00252-X.","startPage":"56","endPage":"75","numberOfPages":"20","costCenters":[],"links":[{"id":207814,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(03)00252-X"},{"id":233038,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"282","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bbf8be4b08c986b329c06","contributors":{"authors":[{"text":"Hay, L.E.","contributorId":54253,"corporation":false,"usgs":true,"family":"Hay","given":"L.E.","email":"","affiliations":[],"preferred":false,"id":403019,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Clark, M.P.","contributorId":49558,"corporation":false,"usgs":true,"family":"Clark","given":"M.P.","affiliations":[],"preferred":false,"id":403018,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025383,"text":"70025383 - 2003 - Variations in flow and transport in thick desert vadose zones in response to paleoclimatic forcing (0-90 kyr): Field measurements, modeling, and uncertainties","interactions":[],"lastModifiedDate":"2018-11-16T08:00:30","indexId":"70025383","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Variations in flow and transport in thick desert vadose zones in response to paleoclimatic forcing (0-90 kyr): Field measurements, modeling, and uncertainties","docAbstract":"An understanding of unsaturated flow and potential recharge in interdrainage semiarid and arid regions is critical for quantification of water resources and contaminant transport. We evaluated system response to paleoclimatic forcing using water potential and Cl profiles and modeling of nonisothermal liquid and vapor flow and Cl transport at semiarid (High Plains, Texas) and arid (Chihuahuan Desert, Texas; Amargosa Desert, Nevada) sites. Infiltration in response to current climatic forcing is restricted to the shallow (∼0.3–3 m) subsurface. Subsurface Cl accumulations correspond to time periods of 9–90 kyr. Bulge-shaped Cl profiles generally represent accumulation during the Holocene (9–16 kyr). Lower Cl concentrations at depth reflect higher water fluxes (0.04–8.4 mm/yr) during the Pleistocene and earlier times. Low water potentials and upward gradients indicate current drying conditions. Nonisothermal liquid and vapor flow simulations indicate that upward flow for at least 1–2 kyr in the High Plains and for 12–16 kyr at the Chihuahuan and Amargosa desert sites is required to reproduce measured upward water potential gradients and that recharge is negligible (<0.1 mm/yr) in these interdrainage areas.
","language":"English","publisher":"AGU Publications","doi":"10.1029/2002WR001604","usgsCitation":"Scanlon, B., Keese, K., Reedy, R., Simunek, J., and Andraski, B.J., 2003, Variations in flow and transport in thick desert vadose zones in response to paleoclimatic forcing (0-90 kyr): Field measurements, modeling, and uncertainties: Water Resources Research, v. 39, no. 7, Article 1179; 17 p., https://doi.org/10.1029/2002WR001604.","productDescription":"Article 1179; 17 p.","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":235893,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"7","noUsgsAuthors":false,"publicationDate":"2003-07-10","publicationStatus":"PW","scienceBaseUri":"505bc17de4b08c986b32a5d6","contributors":{"authors":[{"text":"Scanlon, Bridget R.","contributorId":74093,"corporation":false,"usgs":true,"family":"Scanlon","given":"Bridget R.","affiliations":[],"preferred":false,"id":404983,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Keese, K.","contributorId":15813,"corporation":false,"usgs":true,"family":"Keese","given":"K.","affiliations":[],"preferred":false,"id":404980,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Reedy, R.C.","contributorId":80880,"corporation":false,"usgs":true,"family":"Reedy","given":"R.C.","email":"","affiliations":[],"preferred":false,"id":404982,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Simunek, Jirka","contributorId":9440,"corporation":false,"usgs":false,"family":"Simunek","given":"Jirka","email":"","affiliations":[],"preferred":false,"id":404979,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Andraski, Brian J. 0000-0002-2086-0417 andraski@usgs.gov","orcid":"https://orcid.org/0000-0002-2086-0417","contributorId":168800,"corporation":false,"usgs":true,"family":"Andraski","given":"Brian","email":"andraski@usgs.gov","middleInitial":"J.","affiliations":[{"id":465,"text":"Nevada Water Science Center","active":true,"usgs":true},{"id":38175,"text":"Toxics Substances Hydrology Program","active":true,"usgs":true},{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":false,"id":404981,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ]}