Isotopic variations in melting snow are poorly understood. We made weekly measurements at the Central Sierra Snow Laboratory, California, of snow temperature, density, water equivalent and liquid water volume to examine how physical changes within the snowpackgovern meltwater δ18O. Snowpack samples were extracted at 0.1 m intervals from ground level to the top of the snowpack profile between December 1991 and April 1992. Approximately 800 mm of precipitation fell during the study period with δ18O values between −21.35 and −4.25‰. Corresponding snowpack δ18O ranged from −22.25 to −6.25‰. The coefficient of variation of δ18O in snowpack levels decreased from −0.37 to −0.07 from winter to spring, indicating isotopic snowpack homogenization. Meltwater δ18O ranged from −15.30 to −8.05‰, with variations of up to 2.95‰ observed within a single snowmeltepisode, highlighting the need for frequent sampling. Early snowmelt originated in the lower snowpack with higher δ18O through ground heat flux and rainfall. After the snowpack became isothermal, infiltrating snowmelt displaced the higher δ18O liquid in the lower snowpack through a piston flow process. Fractionation analysis using a two-component mixing model on the isothermal snowpack indicated that δ18O in the initial and final half of major snowmelt was 1.30‰ lower and 1.45‰ higher, respectively, than the value from simple mixing. Mean snowpack δ18O on individual profiling days showed a steady increase from −15.15 to −12.05‰ due to removal of lower δ18O snowmelt and addition of higher δ18O rainfall. Results suggest that direct sampling of snowmelt and snow cores should be undertaken to quantify tracer input compositions adequately. The snowmelt sequence also suggests that regimes of early lower δ18O and later higher δ18O melt may be modeled and used in catchment tracing studies.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0022-1694(01)00596-0","issn":"00221694","usgsCitation":"Unnikrishna, P., McDonnell, J.J., and Kendall, C., 2002, Isotope variations in a Sierra Nevada snowpack and their relation to meltwater: Journal of Hydrology, v. 260, no. 1-4, p. 38-57, https://doi.org/10.1016/S0022-1694(01)00596-0.","productDescription":"20 p.","startPage":"38","endPage":"57","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":207212,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(01)00596-0"},{"id":231967,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"260","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3f8de4b0c8380cd645f0","contributors":{"authors":[{"text":"Unnikrishna, P.V.","contributorId":69327,"corporation":false,"usgs":true,"family":"Unnikrishna","given":"P.V.","email":"","affiliations":[],"preferred":false,"id":401107,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"McDonnell, Jeffery J. 0000-0002-3880-3162","orcid":"https://orcid.org/0000-0002-3880-3162","contributorId":62723,"corporation":false,"usgs":false,"family":"McDonnell","given":"Jeffery","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":401106,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kendall, C. 0000-0002-0247-3405","orcid":"https://orcid.org/0000-0002-0247-3405","contributorId":35050,"corporation":false,"usgs":true,"family":"Kendall","given":"C.","affiliations":[],"preferred":false,"id":401105,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70024396,"text":"70024396 - 2002 - Consistency of patterns in concentration‐discharge plots","interactions":[],"lastModifiedDate":"2018-11-06T13:49:42","indexId":"70024396","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","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":"Consistency of patterns in concentration‐discharge plots","docAbstract":"Concentration‐discharge (c‐Q) plots have been used to infer how flow components such as event water, soil water, and groundwater mix to produce the observed episodic hydrochemical response of small catchments. Because c‐Q plots are based only on observed streamflow and solute concentration, their interpretation requires assumptions about the relative volume, hydrograph timing, and solute concentration of the streamflow end‐members. Evans and Davies [1998] present a taxonomy of c‐Q loops resulting from three‐component conservative mixing. Their analysis, based on a fixed template of end‐member hydrograph volume, timing, and concentration, suggests a unique relationship between c‐Q loop form and the rank order of end‐member concentrations. Many catchments exhibit variability in component contributions to storm flow in response to antecedent conditions or rainfall characteristics, but the effects of such variation on c‐Q relationships have not been studied systematically. Starting with a “baseline” condition similar to that assumed by Evans and Davies [1998], we use a simple computer model to characterize the variability in c‐Q plot patterns resulting from variation in end‐member volume, timing, and solute concentration. Variability in these three factors can result in more than one c‐Q loop shape for a given rank order of end‐member solute concentrations. The number of resulting hysteresis patterns and their relative frequency depends on the rank order of solute concentrations and on their separation in absolute value. In ambiguous cases the c‐Q loop shape is determined by the relative “prominence” of the event water versus soil water components. This “prominence” is broadly defined as a capacity to influence the total streamflow concentration and may result from a combination of end‐member volume, timing, or concentration. The modeling results indicate that plausible hydrological variability in field situations can confound the interpretation of c‐Q plots, even when fundamental end‐member mixing assumptions are satisfied.
Dispersive transport of groundwater solutes was investigated as part of a multispecies reactive tracer test conducted under spatially variable chemical conditions in an unconfined, sewage‐contaminated sand and gravel aquifer on Cape Cod, Massachusetts. Transport of the nonreactive tracer bromide (Br) reflected physical and hydrologic processes. Transport of the reactive tracer nickel (Ni) complexed with an organic ligand (NiEDTA) varied in response to pH and other chemical conditions within the aquifer. A loss of about 14% of the Ni mass was calculated from the distribution of tracers through time. This loss is consistent with reversible adsorption of NiEDTA onto the iron and aluminum oxyhydroxide coatings on the aquifer sediments. The Ni consistently lagged behind Br with a calculated retardation coefficient of 1.2. Longitudinal dispersivities reached constant values of 2.2 and 1.1 m for Br and Ni, respectively, by at least 69 m of travel. The smaller dispersivity for Ni possibly was due to nonlinear or spatially variant adsorption of NiEDTA. In the upper, uncontaminated zone of the aquifer, longitudinal dispersion of Ni was greater than that of Br early in the test as a result of reversible adsorption of NiEDTA. In general, transverse dispersivities were much smaller (horizontal: 1.4–1.5 × 10−2 m; vertical: 0.5–3.8 × 10−3 m) than the longitudinal dispersivities. The Br results are similar to those from a test conducted eight years earlier, suggesting that transport parameters are spatially stationary within the aquifer at the scale of 300 m covered by the spatially overlapping tests. A significant difference between the two tests was the travel distance (69 and 26 m) needed to reach a constant longitudinal dispersivity.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/2001WR000945","usgsCitation":"Hess, K.M., Davis, J., Kent, D.B., and Coston, J.A., 2002, Multispecies reactive tracer test in an aquifer with spatially variable chemical conditions, Cape Cod, Massachusetts: Dispersive transport of bromide and nickel: Water Resources Research, v. 38, no. 8, p. 36-1-36-17, https://doi.org/10.1029/2001WR000945.","productDescription":"1161; 17 p.","startPage":"36-1","endPage":"36-17","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":478703,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/2001wr000945","text":"Publisher Index Page"},{"id":231586,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Massachusetts","otherGeospatial":"Cape Cod","volume":"38","issue":"8","noUsgsAuthors":false,"publicationDate":"2002-08-31","publicationStatus":"PW","scienceBaseUri":"505a60a1e4b0c8380cd715b8","contributors":{"authors":[{"text":"Hess, Kathryn M.","contributorId":49012,"corporation":false,"usgs":true,"family":"Hess","given":"Kathryn","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":401274,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davis, James A.","contributorId":69289,"corporation":false,"usgs":true,"family":"Davis","given":"James A.","affiliations":[],"preferred":false,"id":401276,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kent, Douglas B. 0000-0003-3758-8322 dbkent@usgs.gov","orcid":"https://orcid.org/0000-0003-3758-8322","contributorId":1871,"corporation":false,"usgs":true,"family":"Kent","given":"Douglas","email":"dbkent@usgs.gov","middleInitial":"B.","affiliations":[{"id":37277,"text":"WMA - Earth System Processes Division","active":true,"usgs":true}],"preferred":true,"id":401273,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Coston, Jennifer A.","contributorId":181925,"corporation":false,"usgs":true,"family":"Coston","given":"Jennifer","email":"","middleInitial":"A.","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":401275,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70024462,"text":"70024462 - 2002 - Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments","interactions":[],"lastModifiedDate":"2012-03-12T17:20:06","indexId":"70024462","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1537,"text":"Environmental Forensics","active":true,"publicationSubtype":{"id":10}},"title":"Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments","docAbstract":"Ground and surface waters in urban areas are susceptible to nitrate contamination from septic systems, leaking sewer lines, and fertilizer applications. Source identification is a primary step toward a successful remediation plan in affected areas. In this respect, nitrogen and oxygen isotope ratios of nitrate, in conjunction with hydrologic data and water chemistry, have proven valuable in urban studies from Austin, Texas, and Tacoma, Washington. In Austin, stream water was sampled during stremflow and baseflow conditions to assess surface and subsurface sources of nitrate, respectively. In Tacoma, well waters were sampled in adjacent sewered and un-sewered areas to determine if locally high nitrate concentrations were caused by septic systems in the un-sewered areas. In both studies, sewage was identified as a nitrate source and mixing between sewage and other sources of nitrate was apparent. In addition to source identification, combined nitrogen and oxygen isotopes were important in determining the significance of denitrification, which can complicate source assessment by reducing nitrate concentrations and increasing ??15N values. The two studies illustrate the value of nitrogen and oxygen isotopes of nitrate for forensic applications in urban areas. ?? Published by Elsevier Science Ltd. on behalf of AEHS.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Environmental Forensics","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1006/enfo.2002.0086","issn":"15275922","usgsCitation":"Silva, S.R., Ging, P.B., Lee, R.W., Ebbert, J., Tesoriero, A., and Inkpen, E.L., 2002, Forensic applications of nitrogen and oxygen isotopes in tracing nitrate sources in urban environments: Environmental Forensics, v. 3, no. 2, p. 125-130, https://doi.org/10.1006/enfo.2002.0086.","startPage":"125","endPage":"130","numberOfPages":"6","costCenters":[],"links":[{"id":207820,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1006/enfo.2002.0086"},{"id":233048,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"3","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a1321e4b0c8380cd5452c","contributors":{"authors":[{"text":"Silva, S. R.","contributorId":27474,"corporation":false,"usgs":true,"family":"Silva","given":"S.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":401373,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ging, P. B.","contributorId":50935,"corporation":false,"usgs":true,"family":"Ging","given":"P.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":401375,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lee, R. W.","contributorId":86757,"corporation":false,"usgs":true,"family":"Lee","given":"R.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":401377,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ebbert, J.C.","contributorId":57451,"corporation":false,"usgs":true,"family":"Ebbert","given":"J.C.","affiliations":[],"preferred":false,"id":401376,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Tesoriero, A. J.","contributorId":99127,"corporation":false,"usgs":true,"family":"Tesoriero","given":"A. J.","affiliations":[],"preferred":false,"id":401378,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Inkpen, E. L.","contributorId":39776,"corporation":false,"usgs":true,"family":"Inkpen","given":"E.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":401374,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70024482,"text":"70024482 - 2002 - Methylmercury in flood-control impoundments and natural waters of northwestern Minnesota, 1997-99","interactions":[],"lastModifiedDate":"2018-11-26T10:48:02","indexId":"70024482","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3728,"text":"Water, Air, & Soil Pollution","onlineIssn":"1573-2932","printIssn":"0049-6979","active":true,"publicationSubtype":{"id":10}},"title":"Methylmercury in flood-control impoundments and natural waters of northwestern Minnesota, 1997-99","docAbstract":"We studied methylmercury (MeHg) and total mercury (HgT) in impounded and natural surface waters in northwestern Minnesota, in settings ranging from agricultural to undeveloped. In a recently constructed (1995) permanent-pool impoundment, MeHg levels typically increased from inflow to outflow during 1997; this trend broke down from late 1998 to early 1999. MeHg levels in the outflow reached seasonal maxima in mid-summer (maximum of 1.0 ng L−1 in July 1997) and late-winter (maximum of 6.6 ng L−1 in February 1999), and are comparable to high levels observed in new hydroelectric reservoirs in Canada. Spring and autumn MeHg levels were typically about 0.1–0.2 ng L−1. Overall, MeHg levels in both the inflow (a ditch that drains peatlands) and outflow were significantly higher than in three nearby reference natural lakes. Eleven older permanent-pool impoundments and six natural lakes in northwestern Minnesota were sampled five times. The impoundments typically had higher MeHg levels (0.071–8.36 ng L−1) than natural lakes. Five of six lakes MeHg levels typical of uncontaminated lakes (0.014–1.04 ng L−1) with highest levels in late winter, whereas a hypereutrophic lake had high levels (0.37–3.67 ng L−1) with highest levels in mid-summer. Seven temporary-pool impoundments were sampled during summer high-flow events. Temporary-pool impoundments that retained water for about 10–15 days after innundation yielded pronounced increases in MeHg from inflow to outflow, in one case reaching 4.6 ng L−1, which was about 2 ng L−1 greater than the mean inflow concentration during the runoff event.
","language":"English","publisher":"Kluwer Academic Publishers","doi":"10.1023/A:1015573621474","issn":"00496979","usgsCitation":"Brigham, M.E., Krabbenhoft, D., Olson, M., and DeWild, J., 2002, Methylmercury in flood-control impoundments and natural waters of northwestern Minnesota, 1997-99: Water, Air, & Soil Pollution, v. 138, no. 1, p. 61-78, https://doi.org/10.1023/A:1015573621474.","productDescription":"18 p.","startPage":"61","endPage":"78","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":392,"text":"Minnesota Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":207998,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1023/A:1015573621474"},{"id":233338,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Minnesota","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -96.06994628906249,\n 48.454708881876854\n ],\n [\n -95.8941650390625,\n 48.454708881876854\n ],\n [\n -95.7403564453125,\n 48.44742209577057\n ],\n [\n -95.4876708984375,\n 48.494767515307295\n ],\n [\n -95.34484863281249,\n 48.49112712828191\n ],\n [\n -95.2734375,\n 48.436489955944154\n ],\n [\n -95.2734375,\n 48.356249029540706\n ],\n [\n -95.3173828125,\n 48.20271028869972\n ],\n [\n -95.3338623046875,\n 48.07807894349862\n ],\n [\n -95.361328125,\n 47.94946583788702\n ],\n [\n -95.5975341796875,\n 47.96050238891509\n ],\n [\n -95.7183837890625,\n 48.08908799881762\n ],\n [\n -95.723876953125,\n 48.16242149265211\n ],\n [\n -95.9271240234375,\n 48.22467264956519\n ],\n [\n -96.0919189453125,\n 48.22101291025667\n ],\n [\n -96.15234375,\n 48.3160811030533\n ],\n [\n -96.16333007812499,\n 48.403679418652786\n ],\n [\n -96.06994628906249,\n 48.454708881876854\n ]\n ]\n ]\n }\n },\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -95.9326171875,\n 46.73233101286786\n ],\n [\n -95.899658203125,\n 46.65697731621612\n ],\n [\n -95.899658203125,\n 46.5739667965278\n ],\n [\n -95.9710693359375,\n 46.521075663842836\n ],\n [\n -96.141357421875,\n 46.50973514453879\n ],\n [\n -96.2677001953125,\n 46.521075663842836\n ],\n [\n -96.30615234375,\n 46.57774276255591\n ],\n [\n -96.3336181640625,\n 46.67582559793001\n ],\n [\n -96.295166015625,\n 46.84516443029279\n ],\n [\n -96.119384765625,\n 46.93526088057719\n ],\n [\n -96.17980957031249,\n 47.07386310181414\n ],\n [\n -96.2786865234375,\n 47.15236927446393\n ],\n [\n -96.3720703125,\n 47.28295557691231\n ],\n [\n -96.3720703125,\n 47.3834738721015\n ],\n [\n -96.3775634765625,\n 47.468949677672484\n ],\n [\n -96.3775634765625,\n 47.5913464767971\n ],\n [\n -96.383056640625,\n 47.667237034505156\n ],\n [\n -96.3720703125,\n 47.69497434186282\n ],\n [\n -96.33087158203125,\n 47.73562905149295\n ],\n [\n -96.30340576171875,\n 47.77440623229445\n ],\n [\n -96.15509033203125,\n 47.79286140021344\n ],\n [\n -95.99853515625,\n 47.76148371616669\n ],\n [\n -95.7952880859375,\n 47.68018294648414\n ],\n [\n -95.657958984375,\n 47.59875528481801\n ],\n [\n -95.5426025390625,\n 47.44666502261753\n ],\n [\n -95.5426025390625,\n 47.320206883852414\n ],\n [\n -95.44921875,\n 47.156104775044035\n ],\n [\n -95.4327392578125,\n 47.05141149430736\n ],\n [\n -95.4986572265625,\n 46.95401192579361\n ],\n [\n -95.58654785156249,\n 46.81133924039194\n ],\n [\n -95.73486328124999,\n 46.73233101286786\n ],\n [\n -95.9326171875,\n 46.73233101286786\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"138","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a561de4b0c8380cd6d362","contributors":{"authors":[{"text":"Brigham, M. E.","contributorId":87535,"corporation":false,"usgs":true,"family":"Brigham","given":"M.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":401428,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Krabbenhoft, D. P. 0000-0003-1964-5020","orcid":"https://orcid.org/0000-0003-1964-5020","contributorId":90765,"corporation":false,"usgs":true,"family":"Krabbenhoft","given":"D. P.","affiliations":[],"preferred":false,"id":401429,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Olson, M.L.","contributorId":21989,"corporation":false,"usgs":true,"family":"Olson","given":"M.L.","email":"","affiliations":[],"preferred":false,"id":401426,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"DeWild, J.F. 0000-0003-4097-2798 jfdewild@usgs.gov","orcid":"https://orcid.org/0000-0003-4097-2798","contributorId":56375,"corporation":false,"usgs":true,"family":"DeWild","given":"J.F.","email":"jfdewild@usgs.gov","affiliations":[],"preferred":false,"id":401427,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70024486,"text":"70024486 - 2002 - Grid-cell-based crop water accounting for the famine early warning system","interactions":[],"lastModifiedDate":"2017-04-10T09:51:18","indexId":"70024486","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","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":"Grid-cell-based crop water accounting for the famine early warning system","docAbstract":"Rainfall monitoring is a regular activity of food security analysts for sub-Saharan Africa due to the potentially disastrous impact of drought. Crop water accounting schemes are used to track rainfall timing and amounts relative to phenological requirements, to infer water limitation impacts on yield. Unfortunately, many rain gauge reports are available only after significant delays, and the gauge locations leave large gaps in coverage. As an alternative, a grid-cell-based formulation for the water requirement satisfaction index (WRSI) was tested for maize in Southern Africa. Grids of input variables were obtained from remote sensing estimates of rainfall, meteorological models, and digital soil maps. The spatial WRSI was computed for the 1996–97 and 1997–98 growing seasons. Maize yields were estimated by regression and compared with a limited number of reports from the field for the 1996–97 season in Zimbabwe. Agreement at a useful level (r = 0·80) was observed. This is comparable to results from traditional analysis with station data. The findings demonstrate the complementary role that remote sensing, modelling, and geospatial analysis can play in an era when field data collection in sub-Saharan Africa is suffering an unfortunate decline.
","language":"English","publisher":"Wiley","doi":"10.1002/hyp.1025","issn":"08856087","usgsCitation":"Verdin, J., and Klaver, R., 2002, Grid-cell-based crop water accounting for the famine early warning system: Hydrological Processes, v. 16, no. 8, p. 1617-1630, https://doi.org/10.1002/hyp.1025.","productDescription":"14 p.","startPage":"1617","endPage":"1630","numberOfPages":"14","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":232840,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207684,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.1025"}],"volume":"16","issue":"8","noUsgsAuthors":false,"publicationDate":"2002-06-11","publicationStatus":"PW","scienceBaseUri":"505a2a6fe4b0c8380cd5b19b","contributors":{"authors":[{"text":"Verdin, J. 0000-0003-0238-9657","orcid":"https://orcid.org/0000-0003-0238-9657","contributorId":26112,"corporation":false,"usgs":true,"family":"Verdin","given":"J.","affiliations":[],"preferred":false,"id":401440,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Klaver, R. 0000-0002-3263-9701","orcid":"https://orcid.org/0000-0002-3263-9701","contributorId":40378,"corporation":false,"usgs":true,"family":"Klaver","given":"R.","affiliations":[],"preferred":false,"id":401441,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70024504,"text":"70024504 - 2002 - HIBAL: A hydrologic-isotopic-balance model for application to paleolake systems","interactions":[],"lastModifiedDate":"2012-03-12T17:20:05","indexId":"70024504","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3219,"text":"Quaternary Science Reviews","active":true,"publicationSubtype":{"id":10}},"title":"HIBAL: A hydrologic-isotopic-balance model for application to paleolake systems","docAbstract":"A simple hydrologic-isotopic-balance (HIBAL) model for application to paleolake ??18O records is presented. Inputs to the model include discharge, on-lake precipitation, evaporation, and the ??18O values of these fluid fluxes. Monthly values of climatic parameters that govern the fractionation of 18O and 16O during evaporation have been extracted from historical data sets and held constant in the model. The ability of the model to simulate changes in the hydrologic balance and the ??18O evolution of the mixed layer has been demonstrated using measured data from Pyramid Lake, Nevada. Simulations of the response in ??18O to step- and periodic-function changes in fluid inputs indicate that the hydrologic balance and ??18O values lag climate change. Input of reconstructed river discharges and their ??18O values to Pyramid and Walker lakes indicates that minima and maxima in simulated ??18O records correspond to minima and maxima in the reconstructed volume records and that the overall shape of the volume and ??18O records is similar. The model was also used in a simulation of abrupt oscillations in the ??18O values of paleo-Owens Lake, California.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Quaternary Science Reviews","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0277-3791(01)00094-4","issn":"02773791","usgsCitation":"Benson, L., and Paillet, F., 2002, HIBAL: A hydrologic-isotopic-balance model for application to paleolake systems: Quaternary Science Reviews, v. 21, no. 12-13, p. 1521-1539, https://doi.org/10.1016/S0277-3791(01)00094-4.","startPage":"1521","endPage":"1539","numberOfPages":"19","costCenters":[],"links":[{"id":207884,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0277-3791(01)00094-4"},{"id":233158,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"21","issue":"12-13","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a2e7be4b0c8380cd5c5a2","contributors":{"authors":[{"text":"Benson, L.","contributorId":56793,"corporation":false,"usgs":true,"family":"Benson","given":"L.","affiliations":[],"preferred":false,"id":401510,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Paillet, F.","contributorId":73372,"corporation":false,"usgs":true,"family":"Paillet","given":"F.","email":"","affiliations":[],"preferred":false,"id":401511,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70024505,"text":"70024505 - 2002 - Reconstruction of hydrological changes and response to effective moisture variations from North-Central USA lake sediments","interactions":[],"lastModifiedDate":"2012-03-12T17:20:05","indexId":"70024505","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3219,"text":"Quaternary Science Reviews","active":true,"publicationSubtype":{"id":10}},"title":"Reconstruction of hydrological changes and response to effective moisture variations from North-Central USA lake sediments","docAbstract":"Ratios of the stable isotopes of oxygen and carbon in benthic ostracodes and marl from cores taken from two lakes in north-central Minnesota reflect Holocene hydrological and vegetation changes. Oxygen isotopes show that Williams and Shingobee Lakes, located in the same watershed but with different positions along a hydrologic gradient, were connected before 9.8 ka as part of a larger lake, Lake Willobee. From 9.8-7.7 ka, the level of Lake Willobee fell as a result of glacial retreat and increasing evaporation, leaving small separated basins. Further decreases in lake level after 7.7 ka due to increasing aridity triggered the inflow of ground water in Williams Lake at about 7 ka, and in Shingobee Lake at about 5 ka. After 4 ka effective moisture increased. The carbon-isotope record reflects changes in vegetation with higher ??13C values during the prairie period (7.7-4 ka) and lower values during preceding and succeeding forest periods. The differences in timing of hydrological events show that the biotic and geochemical response of the lakes to climate variations is mediated by their hydrologic systems. The response may be strongly spatially heterogeneous and can result in contrasting information from geochemical and biotic proxies from the same paleorecord. ?? 2002 Elsevier Science Ltd. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Quaternary Science Reviews","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0277-3791(01)00121-4","issn":"02773791","usgsCitation":"Schwalb, A., and Dean, W., 2002, Reconstruction of hydrological changes and response to effective moisture variations from North-Central USA lake sediments: Quaternary Science Reviews, v. 21, no. 12-13, p. 1541-1554, https://doi.org/10.1016/S0277-3791(01)00121-4.","startPage":"1541","endPage":"1554","numberOfPages":"14","costCenters":[],"links":[{"id":207885,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0277-3791(01)00121-4"},{"id":233159,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"21","issue":"12-13","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"50e4a25ce4b0e8fec6cdb59b","contributors":{"authors":[{"text":"Schwalb, A.","contributorId":31129,"corporation":false,"usgs":true,"family":"Schwalb","given":"A.","email":"","affiliations":[],"preferred":false,"id":401512,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dean, W.E.","contributorId":97099,"corporation":false,"usgs":true,"family":"Dean","given":"W.E.","email":"","affiliations":[],"preferred":false,"id":401513,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70024531,"text":"70024531 - 2002 - Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: Groundwater biogeochemistry","interactions":[],"lastModifiedDate":"2012-03-12T17:20:06","indexId":"70024531","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","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":"Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: Groundwater biogeochemistry","docAbstract":"Monitored natural attenuation (MNA) has recently emerged as a viable groundwater remediation technology in the United States. Area 6 at Dover Air Force Base (Dover, DE) was chosen as a test site to examine the potential for MNA of tetrachloroethene (PCE) and trichloroethene (TCE) in groundwater and aquifer sediments. A \"lines of evidence\" approach was used to document the occurrence of natural attenuation. Chlorinated hydrocarbon and biogeochemical data were used to develop a site-specific conceptual model where both anaerobic and aerobic biological processes are responsible for the destruction of PCE, TCE, and daughter metabolites. An examination of groundwater biogeochemical data showed a region of depleted dissolved oxygen with elevated dissolved methane and hydrogen concentrations. Reductive dechlorination likely dominated in the anaerobic portion of the aquifer where PCE and TCE levels were observed to decrease with a simultaneous increase in cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC), ethene, and dissolved chloride. Near the anaerobic/aerobic interface, concentrations of cis-DCE and VC decreased to below detection limits, presumably due to aerobic biotransformation processes. Therefore, the contaminant and daughter product plumes present at the site appear to have been naturally attenuated by a combination of active anaerobic and aerobic biotransformation processes. ?? 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(01)00218-2","issn":"01697722","usgsCitation":"Witt, M., Klecka, G., Lutz, E., Ei, T., Grosso, N., and Chapelle, F.H., 2002, Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: Groundwater biogeochemistry: Journal of Contaminant Hydrology, v. 57, no. 1-2, p. 61-80, https://doi.org/10.1016/S0169-7722(01)00218-2.","startPage":"61","endPage":"80","numberOfPages":"20","costCenters":[],"links":[{"id":207800,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0169-7722(01)00218-2"},{"id":233017,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"57","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a62dbe4b0c8380cd72158","contributors":{"authors":[{"text":"Witt, M.E.","contributorId":82895,"corporation":false,"usgs":true,"family":"Witt","given":"M.E.","email":"","affiliations":[],"preferred":false,"id":401603,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Klecka, G.M.","contributorId":17014,"corporation":false,"usgs":true,"family":"Klecka","given":"G.M.","email":"","affiliations":[],"preferred":false,"id":401600,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lutz, E.J.","contributorId":8260,"corporation":false,"usgs":true,"family":"Lutz","given":"E.J.","email":"","affiliations":[],"preferred":false,"id":401599,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ei, T.A.","contributorId":71733,"corporation":false,"usgs":true,"family":"Ei","given":"T.A.","email":"","affiliations":[],"preferred":false,"id":401602,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Grosso, N.R.","contributorId":70153,"corporation":false,"usgs":true,"family":"Grosso","given":"N.R.","email":"","affiliations":[],"preferred":false,"id":401601,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Chapelle, F. H.","contributorId":101697,"corporation":false,"usgs":true,"family":"Chapelle","given":"F.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":401604,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70024552,"text":"70024552 - 2002 - Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert, USA","interactions":[],"lastModifiedDate":"2018-09-19T08:36:41","indexId":"70024552","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1923,"text":"Hydrogeology Journal","active":true,"publicationSubtype":{"id":10}},"title":"Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert, USA","docAbstract":"Previous studies indicate that a small quantity of recharge occurs from infiltration of streamflow in intermittent streams in the upper Mojave River basin, in the western Mojave Desert, near Victorville, California. Chloride, tritium, and stable isotope data collected in the unsaturated zone between 1994 and 1998 from boreholes drilled in Oro Grande and Sheep Creek Washes indicate that infiltration of streamflow occurs to depths below the root zone, and presumably to the water table, along much of Oro Grande Wash and near the mountain front along Sheep Creek Wash. Differences in infiltration at sites along each wash are the result of hydrologic variables such as proximity to the mountain front, quantity of streamflow, and texture of the subsurface deposits. Differences in infiltration between the washes are the result of large-scale geomorphic processes. For example, Oro Grande wash is incised into the Victorville fan and infiltration has occurred at approximately the same location over recent geologic time. In contrast, Sheep Creek Wash overlies an active alluvial fan and the stream channel can move across the fan surface through time. Infiltration does not occur to depths below the root zone at control sites outside of the washes.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrogeology Journal","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1007/s10040-002-0194-8","issn":"14312174","usgsCitation":"Izbicki, J., Radyk, J., and Michel, R.L., 2002, Movement of water through the thick unsaturated zone underlying Oro Grande and Sheep Creek Washes in the western Mojave Desert, USA: Hydrogeology Journal, v. 10, no. 3, p. 409-427, https://doi.org/10.1007/s10040-002-0194-8.","startPage":"409","endPage":"427","numberOfPages":"19","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":232843,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207685,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s10040-002-0194-8"}],"volume":"10","issue":"3","noUsgsAuthors":false,"publicationDate":"2002-04-24","publicationStatus":"PW","scienceBaseUri":"505a5f27e4b0c8380cd70dd5","contributors":{"authors":[{"text":"Izbicki, J. A. 0000-0003-0816-4408","orcid":"https://orcid.org/0000-0003-0816-4408","contributorId":28244,"corporation":false,"usgs":true,"family":"Izbicki","given":"J. A.","affiliations":[],"preferred":false,"id":401686,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Radyk, J.","contributorId":63984,"corporation":false,"usgs":true,"family":"Radyk","given":"J.","email":"","affiliations":[],"preferred":false,"id":401687,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Michel, R. L.","contributorId":86375,"corporation":false,"usgs":true,"family":"Michel","given":"R.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":401688,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70024589,"text":"70024589 - 2002 - Fluvial sediment transport and deposition following the 1991 eruption of Mount Pinatubo","interactions":[],"lastModifiedDate":"2012-03-12T17:20:14","indexId":"70024589","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1801,"text":"Geomorphology","active":true,"publicationSubtype":{"id":10}},"title":"Fluvial sediment transport and deposition following the 1991 eruption of Mount Pinatubo","docAbstract":"The 1991 eruption of Mount Pinatubo generated extreme sediment yields from watersheds heavily impacted by pyroclastic flows. Bedload sampling in the Pasig-Potrero River, one of the most heavily impacted rivers, revealed negligible critical shear stress and very high transport rates that reflected an essentially unlimited sediment supply and the enhanced mobility of particles moving over a smooth, fine-grained bed. Dimensionless bedload transport rates in the Pasig-Potrero River differed substantially from those previously reported for rivers in temperate regions for the same dimensionless shear stress, but were similar to rates identified in rivers on other volcanoes and ephemeral streams in arid environments. The similarity between volcanically disturbed and arid rivers appears to arise from the lack of an armored bed surface due to very high relative sediment supply; in arid rivers, this is attributed to a flashy hydrograph, whereas volcanically disturbed rivers lack armoring due to sustained high rates of sediment delivery. This work suggests that the increases in sediment supply accompanying massive disturbance induce morphologic and hydrologic changes that temporarily enhance transport efficiency until the watershed recovers and sediment supply is reduced. ?? 2002 Elsevier Science B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Geomorphology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0169-555X(01)00155-6","issn":"0169555X","usgsCitation":"Hayes, S., Montgomery, D.R., and Newhall, C.G., 2002, Fluvial sediment transport and deposition following the 1991 eruption of Mount Pinatubo: Geomorphology, v. 45, no. 3-4, p. 211-224, https://doi.org/10.1016/S0169-555X(01)00155-6.","startPage":"211","endPage":"224","numberOfPages":"14","costCenters":[],"links":[{"id":207641,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0169-555X(01)00155-6"},{"id":232769,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"45","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a12a4e4b0c8380cd543a4","contributors":{"authors":[{"text":"Hayes, S.K.","contributorId":81667,"corporation":false,"usgs":true,"family":"Hayes","given":"S.K.","email":"","affiliations":[],"preferred":false,"id":401808,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Montgomery, D. R.","contributorId":41582,"corporation":false,"usgs":false,"family":"Montgomery","given":"D.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":401807,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Newhall, C. G.","contributorId":93056,"corporation":false,"usgs":true,"family":"Newhall","given":"C.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":401809,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70024618,"text":"70024618 - 2002 - Parasite (Ribeiroia ondatrae) infection linked to amphibian malformations in the western United States","interactions":[],"lastModifiedDate":"2018-11-28T08:41:07","indexId":"70024618","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1459,"text":"Ecological Monographs","active":true,"publicationSubtype":{"id":10}},"title":"Parasite (Ribeiroia ondatrae) infection linked to amphibian malformations in the western United States","docAbstract":"Parasites and pathogens can influence the survivorship, behavior, and very structure of their host species. For example, experimental studies have shown that trematode parasites can cause high frequencies of severe limb malformations in amphibians. In a broad-scale field survey covering parts of California, Oregon, Washington, Idaho, and Montana, we examined relationships between the frequency and types of morphological abnormalities in amphibians and the abundance of trematode parasite infection, pH, concentrations of 61 pesticides, and levels of orthophosphate and total nitrate. We recorded severe malformations at frequencies ranging from 1% to 90% in nine amphibian species from 53 aquatic systems. Infection of larvae by the trematode Ribeiroia ondatrae was associated with, and functionally related to, higher frequencies of amphibian limb malformations than found in uninfected populations (≤5%). Parasites were concentrated around the basal tissue of hind limbs in infected anurans, and malformations associated with infection included skin webbings, supernumerary limbs and digits, and missing or malformed hind limbs. In the absence of Ribeiroia, amphibian populations exhibited low (0-5%) frequencies of abnormalities involving missing digits or distal portions of a hind limb. Species were affected differentially by the parasite, and Ambystoma macrodactylum, Hyla regilla, Rand aurora, R. luteiventris, and Taricha torosa typically exhibited the highest frequencies of abnormalities. None of the water-quality variables measured was associated with malformed amphibians, but aquatic snail hosts (Planorbella spp.) were significant predictors of the presence and abundance of Ribeiroia infection. Morphological comparisons of adult specimens of Ribeiroia collected from different sites and raised in experimental definitive hosts suggested that all samples represented the same species - R. ondatrae. These field results, coupled with experimental research on the effects of Ribeiroia on amphibians, demonstrate that Ribeiroia infection is an important and widespread cause of amphibian limb malformations in the western United States. The relevance of trematode infection to declines of amphibian populations and the influence of habitat modification on the pathology and life cycle of Ribeiroia are emphasized as areas requiring further research.
","language":"English","publisher":"ESA","doi":"10.1890/0012-9615(2002)072[0151:PROILT]2.0.CO;2","issn":"00129615","usgsCitation":"Johnson, P., Lunde, K., Thurman, E., Ritchie, E., Wray, S., Sutherland, D., Kapfer, J., Frest, T., Bowerman, J., and Blaustein, A., 2002, Parasite (Ribeiroia ondatrae) infection linked to amphibian malformations in the western United States: Ecological Monographs, v. 72, no. 2, p. 151-168, https://doi.org/10.1890/0012-9615(2002)072[0151:PROILT]2.0.CO;2.","productDescription":"18 p.","startPage":"151","endPage":"168","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":502602,"rank":1,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://figshare.com/articles/journal_contribution/Parasite_Ribeiroia_ondatrae_infection_linked_to_amphibian_malformations_in_the_western_United_States/20877172","text":"External Repository"},{"id":233308,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","volume":"72","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a74d6e4b0c8380cd77867","contributors":{"authors":[{"text":"Johnson, P.T.J.","contributorId":104255,"corporation":false,"usgs":true,"family":"Johnson","given":"P.T.J.","email":"","affiliations":[],"preferred":false,"id":401934,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lunde, K.B.","contributorId":10200,"corporation":false,"usgs":true,"family":"Lunde","given":"K.B.","email":"","affiliations":[],"preferred":false,"id":401925,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Thurman, E.M.","contributorId":102864,"corporation":false,"usgs":true,"family":"Thurman","given":"E.M.","affiliations":[],"preferred":false,"id":401933,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ritchie, E.G.","contributorId":97285,"corporation":false,"usgs":true,"family":"Ritchie","given":"E.G.","email":"","affiliations":[],"preferred":false,"id":401932,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Wray, S.N.","contributorId":90505,"corporation":false,"usgs":true,"family":"Wray","given":"S.N.","email":"","affiliations":[],"preferred":false,"id":401930,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Sutherland, D.R.","contributorId":15376,"corporation":false,"usgs":true,"family":"Sutherland","given":"D.R.","email":"","affiliations":[],"preferred":false,"id":401926,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Kapfer, J.M.","contributorId":68505,"corporation":false,"usgs":true,"family":"Kapfer","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":401928,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Frest, T.J.","contributorId":70964,"corporation":false,"usgs":true,"family":"Frest","given":"T.J.","email":"","affiliations":[],"preferred":false,"id":401929,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Bowerman, J.","contributorId":94824,"corporation":false,"usgs":true,"family":"Bowerman","given":"J.","email":"","affiliations":[],"preferred":false,"id":401931,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Blaustein, A.R.","contributorId":40325,"corporation":false,"usgs":true,"family":"Blaustein","given":"A.R.","affiliations":[],"preferred":false,"id":401927,"contributorType":{"id":1,"text":"Authors"},"rank":10}]}} ,{"id":70024687,"text":"70024687 - 2002 - The geohydrologic setting of Yucca Mountain, Nevada","interactions":[],"lastModifiedDate":"2012-03-12T17:20:06","indexId":"70024687","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","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":"The geohydrologic setting of Yucca Mountain, Nevada","docAbstract":"This paper provides a geologic and hydrologic framework of the Yucca Mountain region for the geochemical papers in this volume. The regional geologic units, which range in age from late Precambrian through Holocene, are briefly described. Yucca Mountain is composed of dominantly pyroclastic units that range in age from 11.4 to 15.2 Ma. The principal focus of study has been on the Paintbrush Group, which includes two major zoned and welded ash-flow tuffs separated by an important hydrogeologic unit referred to as the Paintbrush non-welded (PTn). The regional structural setting is currently one of extension, and the major local tectonic domains are presented together with a tectonic model that is consistent with the known structures at Yucca Mountain. Streamflow in this arid to semi-arid region occurs principally in intermittent or ephemeral channels. Near Yucca Mountain, the channels of Fortymile Wash and Amargosa River collect infrequent runoff from tributary basins, ultimately draining to Death Valley. Beneath the surface, large-scale interbasin flow of groundwater from one valley to another occurs commonly in the region. Regional groundwater flow beneath Yucca Mountain originates in the high mesas to the north and returns to the surface either in southern Amargosa Desert or in Death Valley, where it is consumed by evapotranspiration. The water table is very deep beneath the upland areas such as Yucca Mountain, where it is 500-750 m below the land surface, providing a large thickness of unsaturated rocks that are potentially suitable to host a nuclear-waste repository. The nature of unsaturated flow processes, which are important for assessing radionuclide migration, are inferred mainly from hydrochemical or isotopic evidence, from pneumatic tests of the fracture systems, and from the results of in situ experiments. Water seeping down through the unsaturated zone flows rapidly through fractures and more slowly through the pores of the rock matrix. Although capillary forces are expected to divert much of the flow around repository openings, some may drip onto waste packages, ultimately causing release of radionuclides, followed by transport down to the water table. ?? 2002 Elsevier Science Ltd. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Applied Geochemistry","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0883-2927(02)00029-X","issn":"08832927","usgsCitation":"Stuckless, J., and Dudley, W.W., 2002, The geohydrologic setting of Yucca Mountain, Nevada: Applied Geochemistry, v. 17, no. 6, p. 659-682, https://doi.org/10.1016/S0883-2927(02)00029-X.","startPage":"659","endPage":"682","numberOfPages":"24","costCenters":[],"links":[{"id":207979,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0883-2927(02)00029-X"},{"id":233313,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"17","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bac53e4b08c986b323412","contributors":{"authors":[{"text":"Stuckless, J. S.","contributorId":6060,"corporation":false,"usgs":true,"family":"Stuckless","given":"J. S.","affiliations":[],"preferred":false,"id":402252,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dudley, W. W.","contributorId":101941,"corporation":false,"usgs":true,"family":"Dudley","given":"W.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":402253,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70024745,"text":"70024745 - 2002 - Effect of growth conditions and staining procedure upon the subsurface transport and attachment behaviors of a groundwater protist","interactions":[],"lastModifiedDate":"2018-11-28T09:38:51","indexId":"70024745","displayToPublicDate":"2002-01-01T00:00:00","publicationYear":"2002","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":850,"text":"Applied and Environmental Microbiology","active":true,"publicationSubtype":{"id":10}},"title":"Effect of growth conditions and staining procedure upon the subsurface transport and attachment behaviors of a groundwater protist","docAbstract":"The transport and attachment behaviors of Spumella guttula (Kent), a nanoflagellate (protist) found in contaminated and uncontaminated aquifer sediments in Cape Cod, Mass., were assessed in flowthrough and static columns and in a field injection-and-recovery transport experiment involving an array of multilevel samplers. Transport of S. guttula harvested from low-nutrient (10 mg of dissolved organic carbon per liter), slightly acidic, granular (porous) growth media was compared to earlier observations involving nanoflagellates grown in a traditional high-nutrient liquid broth. In contrast to the highly retarded (retardation factor of ∼3) subsurface transport previously reported for S. guttula, the peak concentration of porous-medium-grown S. guttulatraveled concomitantly with that of a conservative (bromide) tracer. About one-third of the porous-medium-grown nanoflagellates added to the aquifer were transported at least 2.8 m downgradient, compared to only ∼2% of the broth-grown nanoflagellates. Flowthrough column studies revealed that a vital (hydroethidine [HE]) staining procedure resulted in considerably less attachment (more transport) of S. guttula in aquifer sediments than did a staining-and-fixation procedure involving 4′,6′-diamidino-2-phenylindole (DAPI) and glutaraldehyde. The calculated collision efficiency (∼10−2 for porous-medium-grown, DAPI-stained nanoflagellates) was comparable to that observed earlier for the indigenous community of unattached groundwater bacteria that serve as prey. The attachment of HE-labeled S. guttula onto aquifer sediment grains was independent of pH (over the range from pH 3 to 9) suggesting a primary attachment mechanism that may be fundamentally different from that of their prey bacteria, which exhibit sharp decreases in fractional attachment with increasing pH. The high degree of mobility of S. guttula in the aquifer sediments has important ecological implications for the protistan community within the temporally changing plume of organic contaminants in the Cape Cod aquifer.