The south-eastern United States and Gulf Coast of Mexico is physiographically diverse, although dominated by a broad coastal plain. Much of the region has a humid, warm temperate climate with little seasonality in precipitation but strong seasonality in runoff owing to high rates of summer evapotranspiration. The climate of southern Florida and eastern Mexico is subtropical with a distinct summer wet season and winter dry season. Regional climate models suggest that climate change resulting from a doubling of the pre-industrial levels of atmospheric CO2 may increase annual air temperatures by 3-4??C. Changes in precipitation are highly uncertain, but the most probable scenario shows higher levels over all but the northern, interior portions of the region, with increases primarily occurring in summer and occurring as more intense or clustered storms. Despite the increases in precipitation, runoff is likely to decline over much of the region owing to increases in evapotranspiration exceeding increases in precipitation. Only in Florida and the Gulf Coast areas of the US and Mexico are precipitation increases likely to exceed evapotranspiration increases, producing an increase in runoff. However, increases in storm intensity and clustering are likely to result in more extreme hydrographs, with larger peaks in flow but lower baseflows and longer periods of drought. The ecological effects of climate change on freshwaters of the region include: (1) a general increase in rates of primary production, organic matter decomposition and nutrient cycling as a result of higher temperatures and longer growing seasons: (2) reduction in habitat for cool water species, particularly fish and macroinvertebrates in Appalachian streams; (3) reduction in water quality and in suitable habitat in summer owing to lower baseflows and intensification of the temperature-dissolved oxygen squeeze in many rivers and reservoirs; (4) reduction in organic matter storage and loss of organisms during more intense flushing events in some streams and wetlands; (5) shorter periods of inundation of riparian wetlands and greater drying of wetland soils, particularly in northern and inland areas; (6) expansion of subtropical species northwards, including several non-native nuisance species currently confined to southern Florida; (7) expansion of wetlands in Florida and coastal Mexico, but increase in eutrophication of Florida lakes as a result of greater runoff from urban and agricultural areas; and (8) changes in the flushing rate of estuaries that would alter their salinity regimes, stratification and water quality as well as influence productivity in the Gulf of Mexico. Many of the expected climate change effects will exacerbate current anthropogenic stresses on the region's freshwater systems, including increasing demands for water, increasing waste heat loadings and land use changes that alter the quantity and quality of runoff to streams and reservoirs. Research is needed especially in several critical areas: long-term monitoring of key hydrological, chemical and biological properties (particularly water balances in small, forested catchments and temperature-sensitive species); experimental studies of the effects of warming on organisms and ecosystem processes under realistic conditions (e.g. in situ heating experiments); studies of the effects of natural hydrological variation on biological communities; and assessment of the effects of water management activities on organisms and ecosystem processes, including development and testing of management and restoration strategies designed to counteract changes in climate.
","language":"English","publisher":"Wiley","issn":"08856087","usgsCitation":"Mulholland, P.J., Best, G., Coutant, C., Hornberger, G., Meyer, J., Robinson, P., Stenberg, J., Turner, R., Vera-Herrera, F., and Wetzel, R., 1997, Effects of climate change on freshwater ecosystems of the south-eastern United States and the Gulf Coast of Mexico: Hydrological Processes, v. 11, no. 8, p. 949-970.","productDescription":"22 p.","startPage":"949","endPage":"970","numberOfPages":"22","costCenters":[],"links":[{"id":228174,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"11","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a06aee4b0c8380cd51385","contributors":{"authors":[{"text":"Mulholland, P. J.","contributorId":89081,"corporation":false,"usgs":false,"family":"Mulholland","given":"P.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":383784,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Best, G.R.","contributorId":27007,"corporation":false,"usgs":true,"family":"Best","given":"G.R.","email":"","affiliations":[],"preferred":false,"id":383778,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Coutant, C.C.","contributorId":15470,"corporation":false,"usgs":true,"family":"Coutant","given":"C.C.","affiliations":[],"preferred":false,"id":383777,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hornberger, G.M.","contributorId":68463,"corporation":false,"usgs":true,"family":"Hornberger","given":"G.M.","email":"","affiliations":[],"preferred":false,"id":383782,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Meyer, J.L.","contributorId":73316,"corporation":false,"usgs":true,"family":"Meyer","given":"J.L.","email":"","affiliations":[],"preferred":false,"id":383783,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Robinson, P.J.","contributorId":43232,"corporation":false,"usgs":true,"family":"Robinson","given":"P.J.","email":"","affiliations":[],"preferred":false,"id":383780,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Stenberg, J.R.","contributorId":7140,"corporation":false,"usgs":true,"family":"Stenberg","given":"J.R.","email":"","affiliations":[],"preferred":false,"id":383776,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Turner, R.E.","contributorId":39749,"corporation":false,"usgs":false,"family":"Turner","given":"R.E.","email":"","affiliations":[{"id":16756,"text":"Louisiana State University, Baton Rouge, LA","active":true,"usgs":false}],"preferred":false,"id":383779,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Vera-Herrera, F.","contributorId":95762,"corporation":false,"usgs":true,"family":"Vera-Herrera","given":"F.","affiliations":[],"preferred":false,"id":383785,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Wetzel, R.G.","contributorId":60403,"corporation":false,"usgs":true,"family":"Wetzel","given":"R.G.","email":"","affiliations":[],"preferred":false,"id":383781,"contributorType":{"id":1,"text":"Authors"},"rank":10}]}} ,{"id":70019742,"text":"70019742 - 1997 - Microorganisms as tracers in groundwater injection and recovery experiments: A review","interactions":[],"lastModifiedDate":"2019-02-13T16:26:42","indexId":"70019742","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1621,"text":"FEMS Microbiology Reviews","active":true,"publicationSubtype":{"id":10}},"title":"Microorganisms as tracers in groundwater injection and recovery experiments: A review","docAbstract":"Modern day injection and recovery techniques designed to examine the transport behavior of microorganisms in groundwater have evolved from experiments conducted in the late 1800s, in which bacteria that form red or yellow pigments were used to trace flow paths through karst and fractured- rock aquifers. A number of subsequent groundwater hydrology studies employed bacteriophage that can be injected into aquifers at very high concentrations (e g., 1013 phage ml-1) and monitored through many log units of dilution to follow groundwater flow paths for great distances, particularly in karst terrain. Starting in the 1930s, microbial indicators of fecal contamination (particularly coliform bacteria and their coliphages) were employed as tracers to determine potential migration of pathogens in groundwater. Several injection and recovery experiments performed in the 1990s employed indigenous groundwater microorganisms (both cultured and uncultured) that are better able to survive under in situ conditions. Better methods for labeling native bacteria (e.g by stable isotope labeling or inserting genetic markers; such as the ability to cause ice nucleation) are being developed that will not compromise the organisms' viability during the experimental time course.","language":"English","publisher":"Oxford","doi":"10.1016/S0168-6445(97)00026-0","issn":"01686445","usgsCitation":"Harvey, R., 1997, Microorganisms as tracers in groundwater injection and recovery experiments: A review: FEMS Microbiology Reviews, v. 20, no. 3-4, p. 461-472, https://doi.org/10.1016/S0168-6445(97)00026-0.","productDescription":"12 p.","startPage":"461","endPage":"472","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479976,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1016/s0168-6445(97)00026-0","text":"Publisher Index Page"},{"id":228056,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206046,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0168-6445(97)00026-0"}],"volume":"20","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a568be4b0c8380cd6d67a","contributors":{"authors":[{"text":"Harvey, R.W. 0000-0002-2791-8503","orcid":"https://orcid.org/0000-0002-2791-8503","contributorId":11757,"corporation":false,"usgs":true,"family":"Harvey","given":"R.W.","affiliations":[],"preferred":false,"id":383762,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019524,"text":"70019524 - 1997 - Hydrological and chemical estimates of the water balance of a closed-basin lake in north central Minnesota","interactions":[],"lastModifiedDate":"2018-03-15T10:21:48","indexId":"70019524","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Hydrological and chemical estimates of the water balance of a closed-basin lake in north central Minnesota","docAbstract":"Chemical mass balances for sodium, magnesium, chloride, dissolved organic carbon, and oxygen 18 were used to estimate groundwater seepage to and from Williams Lake, Minnesota, over a 15-month period, from April 1991 through June 1992. Groundwater seepage to the lake and seepage from the lake to groundwater were determined independently using a flow net approach using data from water table wells installed as part of the study. Hydrogeological analysis indicated groundwater seepage to the lake accounted for 74% of annual water input to the lake; the remainder came from atmospheric precipitation, as determined from a gage in the watershed and from nearby National Weather Service gages. Seepage from the lake accounted for 69% of annual water losses from the lake; the remainder was removed by evaporation, as determined by the energy budget method. Calculated annual water loss exceeded calculated annual water gain, and this imbalance was double the value of the independently measured decrease in lake volume. Seepage to the lake determined from oxygen 18 was larger (79% of annual water input) than that determined from the flow net approach and made the difference between calculated annual water gain and loss consistent with the independently measured decrease in lake volume. Although the net difference between volume of seepage to the lake and volume of seepage from the lake was 1% of average lake volume, movement of water into and out of the lake by seepage represented an annual exchange of groundwater with the lake equal to 26–27% of lake volume. Estimates of seepage to the lake from sodium, magnesium, chloride, and dissolved organic carbon did not agree with the values determined from flow net approach or oxygen 18. These results indicated the importance of using a combination of hydrogeological and chemical approaches to define volume of seepage to and from Williams Lake and identify uncertainties in chemical fluxes.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/97WR02427","usgsCitation":"LaBaugh, J.W., Winter, T.C., Rosenberry, D.O., Schuster, P.F., Reddy, M.M., and Aiken, G.R., 1997, Hydrological and chemical estimates of the water balance of a closed-basin lake in north central Minnesota: Water Resources Research, v. 33, no. 12, p. 2799-2812, https://doi.org/10.1029/97WR02427.","productDescription":"14 p.","startPage":"2799","endPage":"2812","costCenters":[],"links":[{"id":226431,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Minnesota","otherGeospatial":"Williams Lake","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -94.67612028121948,\n 46.948504487557834\n ],\n [\n -94.66281652450562,\n 46.948504487557834\n ],\n [\n -94.66281652450562,\n 46.9591673117941\n ],\n [\n -94.67612028121948,\n 46.9591673117941\n ],\n [\n -94.67612028121948,\n 46.948504487557834\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"33","issue":"12","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a36a9e4b0c8380cd608c3","contributors":{"authors":[{"text":"LaBaugh, James W. 0000-0002-4112-2536 jlabaugh@usgs.gov","orcid":"https://orcid.org/0000-0002-4112-2536","contributorId":1311,"corporation":false,"usgs":true,"family":"LaBaugh","given":"James","email":"jlabaugh@usgs.gov","middleInitial":"W.","affiliations":[{"id":493,"text":"Office of Ground Water","active":true,"usgs":true},{"id":27111,"text":"National Water Quality Program","active":true,"usgs":true}],"preferred":true,"id":383053,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Winter, Thomas C.","contributorId":84736,"corporation":false,"usgs":true,"family":"Winter","given":"Thomas","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":383054,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rosenberry, Donald O. 0000-0003-0681-5641 rosenber@usgs.gov","orcid":"https://orcid.org/0000-0003-0681-5641","contributorId":1312,"corporation":false,"usgs":true,"family":"Rosenberry","given":"Donald","email":"rosenber@usgs.gov","middleInitial":"O.","affiliations":[{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true},{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":383057,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Schuster, Paul F. 0000-0002-8314-1372 pschuste@usgs.gov","orcid":"https://orcid.org/0000-0002-8314-1372","contributorId":1360,"corporation":false,"usgs":true,"family":"Schuster","given":"Paul","email":"pschuste@usgs.gov","middleInitial":"F.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true},{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true}],"preferred":true,"id":383056,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Reddy, Michael M. mmreddy@usgs.gov","contributorId":684,"corporation":false,"usgs":true,"family":"Reddy","given":"Michael","email":"mmreddy@usgs.gov","middleInitial":"M.","affiliations":[{"id":145,"text":"Branch of Regional Research-Central Region","active":false,"usgs":true}],"preferred":true,"id":383055,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Aiken, George R. 0000-0001-8454-0984 graiken@usgs.gov","orcid":"https://orcid.org/0000-0001-8454-0984","contributorId":1322,"corporation":false,"usgs":true,"family":"Aiken","given":"George","email":"graiken@usgs.gov","middleInitial":"R.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true},{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true}],"preferred":true,"id":383052,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70019302,"text":"70019302 - 1997 - Environment of ore deposition in the creede mining district, San Juan Mountains, Colorado: Part V. Epithermal mineralization from fluid mixing in the OH vein","interactions":[],"lastModifiedDate":"2018-10-30T11:39:59","indexId":"70019302","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1472,"text":"Economic Geology","active":true,"publicationSubtype":{"id":10}},"title":"Environment of ore deposition in the creede mining district, San Juan Mountains, Colorado: Part V. Epithermal mineralization from fluid mixing in the OH vein","docAbstract":"Detailed fluid inclusion studies on coarse-grained sphalerite from the OH vein, Creede, Colorado, have shown that the abrupt color changes between growth zones correspond to abrupt changes in the nature of the ore fluids. Within each growth zone, however, the composition of the fluids remained constant. The base of a distinctive orange-brown growth zone marks a sharp increase in both temperature and salinity relative to the preceding yellow-white zone. The orange-brown growth zone can be correlated along much of the vein and is believed to represent a time-stratigraphic interval. Along the vein, temperatures and salinities of fluid inclusions within this interval show a systematic decrease from about 285??C and 11.5 wt percent NaCl equiv near the base of the vein to about 250??C and 8 wt percent NaCl equiv, respectively, near the top of the vein. The iron concentration of this sphalerite growth zone shows a similar pattern, decreasing from about 2.8 to 1.2 mole percent FeS. When plotted on an enthalpy-salinity diagram, the fluid inclusion data define a spatial trend indicating the progressive mixing of deeply circulating hydrothermal brines with overlying, dilute ground waters. The hydrothermal brines entered the OH vein from below at a temperature, salinity, and density of approximately 285??C, 11.5 wt percent NaCl equiv, and 860 kg/m3, respectively, whereas the overlying ground waters appear to have been preheated to roughly 150??C and had an assumed salinity of 0 wt percent and a density of 920 kg/m3. The greater density of the heated ground water promoted mixing with the hydrothermal brine within the open fractures, causing sphalerite deposition. Although there were also episodes of boiling during vein mineralization, boiling appears unimportant for this sphalerite. Isotopic evidence and geochemical modeling studies also indicate that mixing was the depositional mechanism for sphalerite. An important aspect of the mixing hydrology of the Creede system involves an aquitard overlying the OH vein. This low permeability zone restricted the flow of ground water into the vein from above and forced the upwelling hydrothermal fluids to flow laterally along the vein. The mixing environment thus occurred along the interface between a deeply circulating hydrothermal convection cell and a topographically driven shallow ground-water system.","language":"English","publisher":"Society of Economic Geologists","doi":"10.2113/gsecongeo.92.1.29","issn":"03610128","usgsCitation":"Hayba, D., 1997, Environment of ore deposition in the creede mining district, San Juan Mountains, Colorado: Part V. Epithermal mineralization from fluid mixing in the OH vein: Economic Geology, v. 92, no. 1, p. 29-44, https://doi.org/10.2113/gsecongeo.92.1.29.","productDescription":"16 p.","startPage":"29","endPage":"44","costCenters":[{"id":245,"text":"Eastern Mineral and Environmental Resources Science Center","active":true,"usgs":true}],"links":[{"id":226738,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"92","issue":"1","noUsgsAuthors":false,"publicationDate":"1997-02-01","publicationStatus":"PW","scienceBaseUri":"505a098be4b0c8380cd51f75","contributors":{"authors":[{"text":"Hayba, D.O. 0000-0003-4092-1894","orcid":"https://orcid.org/0000-0003-4092-1894","contributorId":57850,"corporation":false,"usgs":true,"family":"Hayba","given":"D.O.","affiliations":[],"preferred":false,"id":382295,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019268,"text":"70019268 - 1997 - Tracing hydrologic pathways at the Panola Mountain research watershed, Georgia, USA","interactions":[],"lastModifiedDate":"2012-03-12T17:19:16","indexId":"70019268","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1920,"text":"Hydrochemistry. Proc. international symposium, Rabat, Morocco, 1997","active":true,"publicationSubtype":{"id":10}},"title":"Tracing hydrologic pathways at the Panola Mountain research watershed, Georgia, USA","docAbstract":"An analysis of Cl- concentrations and fluxes at the Panola Mountain Research Watershed indicates that Cl- may be effectively used to differentiate 'new' and 'old' water flow through the hillslope and their respective contributions to streamwater. Rainfall and throughfall, the 'new' water inputs, are marked by low Cl- concentrations (15 ??eq 1-1). Stormwater moves rapidly to depth along preferred pathways in a deciduous forest hillslope, as evidenced by low concentrations (20 ??eq 1-1) in mobile soil water from zero-tension stainless-steel pan lysimeters. 'Old' waters, matrix soil waters and groundwater, typically have high concentrations (20 ??eq 1-1). Timing of soil water transport is not sufficiently rapid to suggest that soil water from the hillslope contributes to streamwater for an individual rainstorm. The source of streamflow, therefore, must be a combination of channel interception, runoff from near-channel areas, and runoff from a 3-ha bedrock outcrop in the headwaters. Groundwater contribution to streamflow was estimated using Cl- concentrations of throughfall and groundwater as the two end members for a two-component hydrograph separation. For the study period, groundwater contributed 79% of the runoff and from 1985 to 1995, contributed 75% of the runoff. Rainfall was the source of 45% of the Cl- flux from the watershed in the long term; the remaining Cl- is hypothesized to be derived from dry deposition, consistent with the enrichment noted for throughfall. At peak flow during individual rainstorms, 'new' water can contribute 95% of the runoff.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrochemistry. Proc. international symposium, Rabat, Morocco, 1997","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","usgsCitation":"Peters, N., and Ratcliffe, E., 1997, Tracing hydrologic pathways at the Panola Mountain research watershed, Georgia, USA: Hydrochemistry. Proc. international symposium, Rabat, Morocco, 1997, v. 244, p. 275-289.","startPage":"275","endPage":"289","numberOfPages":"15","costCenters":[],"links":[{"id":226915,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"244","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb693e4b08c986b326d53","contributors":{"authors":[{"text":"Peters, N.E.","contributorId":33332,"corporation":false,"usgs":true,"family":"Peters","given":"N.E.","email":"","affiliations":[],"preferred":false,"id":382192,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ratcliffe, E.B.","contributorId":33857,"corporation":false,"usgs":true,"family":"Ratcliffe","given":"E.B.","email":"","affiliations":[],"preferred":false,"id":382193,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019253,"text":"70019253 - 1997 - A theoretically based determination of bowen-ratio fetch requirements","interactions":[],"lastModifiedDate":"2019-02-04T10:56:48","indexId":"70019253","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1072,"text":"Boundary-Layer Meteorology","active":true,"publicationSubtype":{"id":10}},"title":"A theoretically based determination of bowen-ratio fetch requirements","docAbstract":"Determination of fetch requirements for accurate Bowen-ratio measurements of latent- and sensible-heat fluxes is more involved than for eddy-correlation measurements because Bowen-ratio sensors are located at two heights, rather than just one. A simple solution to the diffusion equation is used to derive an expression for Bowen-ratio fetch requirements, downwind of a step change in surface fluxes. These requirements are then compared to eddy-correlation fetch requirements based on the same diffusion equation solution. When the eddy-correlation and upper Bowen-ratio sensor heights are equal, and the available energy upwind and downwind of the step change is constant, the Bowen-ratio method requires less fetch than does eddy correlation. Differences in fetch requirements between the two methods are greatest over relatively smooth surfaces. Bowen-ratio fetch can be reduced significantly by lowering the lower sensor, as well as the upper sensor. The Bowen-ratio fetch model was tested using data from a field experiment where multiple Bowen-ratio systems were deployed simultaneously at various fetches and heights above a field of bermudagrass. Initial comparisons were poor, but improved greatly when the model was modified (and operated numerically) to account for the large roughness of the upwind cotton field.","language":"English","publisher":"Springer","doi":"10.1023/A:1000286829849","issn":"00068314","usgsCitation":"Stannard, D., 1997, A theoretically based determination of bowen-ratio fetch requirements: Boundary-Layer Meteorology, v. 83, no. 3, p. 375-406, https://doi.org/10.1023/A:1000286829849.","productDescription":"32 p.","startPage":"375","endPage":"406","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":226638,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"83","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e5fae4b0c8380cd47093","contributors":{"authors":[{"text":"Stannard, D.I.","contributorId":100884,"corporation":false,"usgs":true,"family":"Stannard","given":"D.I.","email":"","affiliations":[],"preferred":false,"id":382143,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019249,"text":"70019249 - 1997 - Advances in ice radar studies of a temperate alpine glacier, South Cascade Glacier, Washington, U.S.A.","interactions":[],"lastModifiedDate":"2023-01-31T00:34:42.271626","indexId":"70019249","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":794,"text":"Annals of Glaciology","active":true,"publicationSubtype":{"id":10}},"title":"Advances in ice radar studies of a temperate alpine glacier, South Cascade Glacier, Washington, U.S.A.","docAbstract":"South Cascade Glacier, Washington, U.S.A., is one of the most extensively studied glaciers in the Western Hemisphere. In addition to mass-balance measurements, which date to 1958, numerous hydrological investigations have been carried out during the last three decades, and repeated ice-thickness determinations have been made using a variety of techniques. In the late 1960s, the basal topography was initially determined by gravitimetric methods. In the mid-1970s some of the first depth measurements using radar on temperate ice were made. The basal topography was remapped soon after from a series of point radar measurements and boreholes drilled to the glacier bottom. During the 1990s, the ice thickness was remapped using digital recording of continuous profiles that obtained over 5000 ice-thickness measurements. Profiles have been corrected for the finite beamwidth of the antenna radiation pattern and reflections in steep terrain, resulting in a significantly improved depiction of the basal surface and internal structures. The map based on our recent radar profiles confirms the large-scale features of the basal topography previously depicted and reveals more structural detail. A bright reflector was detected at the base of the glacier and could be traced in adjacent profiles. Comparison with results from water-level measurements in boreholes drilled to the bed indicates that the reflector is a subglacial conduit.","language":"English","publisher":"Cambridge University Press","doi":"10.3189/S0260305500012350","issn":"02603055","usgsCitation":"Fountain, A.G., and Jacobel, R., 1997, Advances in ice radar studies of a temperate alpine glacier, South Cascade Glacier, Washington, U.S.A.: Annals of Glaciology, v. 24, p. 303-308, https://doi.org/10.3189/S0260305500012350.","productDescription":"6 p.","startPage":"303","endPage":"308","costCenters":[],"links":[{"id":480085,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3189/s0260305500012350","text":"Publisher Index Page"},{"id":226591,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Washington","otherGeospatial":"North Cascade Mountains, South Cascade Glacier","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -121.04278506024454,\n 48.34552898711394\n ],\n [\n -121.04036929136396,\n 48.347650640562364\n ],\n [\n -121.03959279422392,\n 48.349657528750214\n ],\n [\n -121.04174973072423,\n 48.35223769743416\n ],\n [\n -121.04468316436498,\n 48.35177901032762\n ],\n [\n -121.04847937260617,\n 48.35143499228772\n ],\n [\n -121.04830681768601,\n 48.353843069792134\n ],\n [\n -121.05115397386666,\n 48.35722565311198\n ],\n [\n -121.05003236688626,\n 48.35917483641845\n ],\n [\n -121.05210302592687,\n 48.362442417587886\n ],\n [\n -121.05141280624687,\n 48.365939070518436\n ],\n [\n -121.05486390464776,\n 48.36725741832126\n ],\n [\n -121.05624434400804,\n 48.36977937989849\n ],\n [\n -121.06150726906924,\n 48.37121225697274\n ],\n [\n -121.06288770842953,\n 48.37184271011205\n ],\n [\n -121.06892713063112,\n 48.3703525355663\n ],\n [\n -121.068064356031,\n 48.36840377997524\n ],\n [\n -121.06616625191057,\n 48.36639763014654\n ],\n [\n -121.06858202079115,\n 48.35745497266612\n ],\n [\n -121.06694274905061,\n 48.35355639986648\n ],\n [\n -121.06340537318968,\n 48.35137765572216\n ],\n [\n -121.06297398588961,\n 48.3487401039564\n ],\n [\n -121.06012682970896,\n 48.346274442984594\n ],\n [\n -121.05546784686766,\n 48.34512758328265\n ],\n [\n -121.05365602020731,\n 48.344382110637525\n ],\n [\n -121.04709893324554,\n 48.344955552101624\n ],\n [\n -121.04278506024454,\n 48.34552898711394\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"24","noUsgsAuthors":false,"publicationDate":"2017-01-20","publicationStatus":"PW","scienceBaseUri":"5059e704e4b0c8380cd477cb","contributors":{"authors":[{"text":"Fountain, A. G.","contributorId":29815,"corporation":false,"usgs":true,"family":"Fountain","given":"A.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":382134,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Jacobel, R.W.","contributorId":27619,"corporation":false,"usgs":true,"family":"Jacobel","given":"R.W.","email":"","affiliations":[],"preferred":false,"id":382133,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019227,"text":"70019227 - 1997 - Nesting season food habits of 4 species of Herons and Egrets at Lake Okeechobee, Florida","interactions":[],"lastModifiedDate":"2012-03-12T17:19:28","indexId":"70019227","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3731,"text":"Waterbirds","onlineIssn":"19385390","printIssn":"15244695","active":true,"publicationSubtype":{"id":10}},"title":"Nesting season food habits of 4 species of Herons and Egrets at Lake Okeechobee, Florida","docAbstract":"Based on the composition of nestling regurgitations collected during 3 breeding seasons, fish were the most important prey group for Great Egrets (Ardea alba: N = 200 nest-day samples; aggregate percent biomass [APB] = 73.4%), Snowy Egrets (Egretta thula: N = 115; APB = 91.4%), and Tricolored Herons (E. tricolor. N = 68; APB = 97.3%). For Little Blue Herons (E. caerulerr. N = 57), grass shrimp (Palaemoneles paludosus; APB = 39.7%) ranked higher in overall importance than all fishes combined (APB = 36.5%). Dietary overlap, as measured by Schoener's Similarity Index, was greatest between Snowy Egrets and Tricolored Herons (77%) and lowest between Tricolored Herons and Little Blue Herons (30%). Diet diversity, as measured by Shannon's Index, was highest for Great Egrets (2.04), intermediate for Snowy Egrets (1.71) and Tricolored Herons (1.68), and lowest for Little Blue Herons (1.60). Great Egrets ate a wider variety of fish species and sizes, especially larger fishes, and more crayfish than the other species. Little Blue Herons ate fewer fish and more grass shrimp and insects, and ate smaller forage fishes than Tricolored Herons but similar-sized fish as Snowy Egrets. The coarse-scale trophic composition of Snowy Egret and Tricolored Heron diets did not differ significantly, but Tricolored Herons ate larger forage fishes than Snowy Egrets. Pronounced interannual and intercolony variation in diet composition suggested that Great Egrets and Little Blue Herons switched prey types as hydrologic conditions and habitat availability changed. Conversely, lack of such variation suggested that Snowy Egrets and Tricolored Herons adjusted their foraging tactics to ensure contin-ued encounters with preferred prey despite changing habitat conditions. These results are generally consistent with other published data, help confirm some generalizations about foraging strategies and patterns of niche differentiation among these ecologically similar species, and have implications for managing the Lake Okeechobce ecosystem.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Waterbirds","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"07386028","usgsCitation":"Smith, J., 1997, Nesting season food habits of 4 species of Herons and Egrets at Lake Okeechobee, Florida: Waterbirds, v. 20, no. 2, p. 198-220.","startPage":"198","endPage":"220","numberOfPages":"23","costCenters":[],"links":[{"id":226282,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"20","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a64d6e4b0c8380cd72a7a","contributors":{"authors":[{"text":"Smith, J.P.","contributorId":54276,"corporation":false,"usgs":true,"family":"Smith","given":"J.P.","email":"","affiliations":[],"preferred":false,"id":382070,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019223,"text":"70019223 - 1997 - Modeling saltwater upconing in a freshwater aquifer in south-central Kansas","interactions":[],"lastModifiedDate":"2012-03-12T17:19:16","indexId":"70019223","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Modeling saltwater upconing in a freshwater aquifer in south-central Kansas","docAbstract":"The Great Bend Prairie freshwater alluvial aquifer in south-central Kansas overlies a bedrock brine aquifer of Permian age. The continuous extraction of freshwater mainly for irrigation in this area has accelerated the upward movement of the saltwater, resulting in the deterioration of water quality. Predicting saltwater upconing is critical for maintaining a long-term supply of water of good quality to the Groundwater Management District No. 5. This paper uses a numerical model to predict the effect of saltwater upconing on the salinity of pumped water. A sensitivity analysis was conducted for estimating the effects of uncertainties in model parameters on the numerical results. The most important factors affecting the salinity of discharged water are found to be the location and nature of clay layers in the aquifer, the pumping rate, the location of the well screen, and the hydraulic conductivities of the medium. The effect of uncertainties in aquifer porosity and dispersivity on salinity is appreciable but not substantial, whereas that of recharge from precipitation in the study area is relatively insignificant. In addition, a numerical model based on the field conditions observed at the Siefkes site was constructed and calibrated to reproduce and project the variation of measured water levels and discharged groundwater concentration. Finally, a number of practical management recommendations based on this study are presented.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier Sci B.V.","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/S0022-1694(97)00048-6","issn":"00221694","usgsCitation":"Ma, T., Sophocleous, M., Yu, Y., and Buddemeier, R., 1997, Modeling saltwater upconing in a freshwater aquifer in south-central Kansas: Journal of Hydrology, v. 201, no. 1-4, p. 120-137, https://doi.org/10.1016/S0022-1694(97)00048-6.","startPage":"120","endPage":"137","numberOfPages":"18","costCenters":[],"links":[{"id":205808,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(97)00048-6"},{"id":226913,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"201","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a5c25e4b0c8380cd6fa8c","contributors":{"authors":[{"text":"Ma, T.-S.","contributorId":67232,"corporation":false,"usgs":true,"family":"Ma","given":"T.-S.","email":"","affiliations":[],"preferred":false,"id":382047,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sophocleous, M.","contributorId":13373,"corporation":false,"usgs":true,"family":"Sophocleous","given":"M.","email":"","affiliations":[],"preferred":false,"id":382046,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Yu, Y.-S.","contributorId":98892,"corporation":false,"usgs":true,"family":"Yu","given":"Y.-S.","email":"","affiliations":[],"preferred":false,"id":382049,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Buddemeier, R. W.","contributorId":86492,"corporation":false,"usgs":true,"family":"Buddemeier","given":"R. W.","affiliations":[],"preferred":false,"id":382048,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020150,"text":"70020150 - 1997 - Assessing hydrogeochemical heterogeneity in natural and constructed wetlands","interactions":[],"lastModifiedDate":"2019-02-13T06:49:06","indexId":"70020150","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1007,"text":"Biogeochemistry","active":true,"publicationSubtype":{"id":10}},"title":"Assessing hydrogeochemical heterogeneity in natural and constructed wetlands","docAbstract":"While 'water quality function' is cited as an important wetland function to design for and preserve, we demonstrate that the scale at which hydrochemical samples are collected can significantly influence interpretations of biogeochemical processes in wetlands. Subsurface, chemical profiles for both nutrients and major ions were determined at a site in southwestern Wisconsin that contained areas of both natural and constructed wetlands. Sampling was conducted on three different scales: (1) a large scale (3 m between sampling points), (2) an intermediate scale (0.15 m between sampling points), and (3) a small scale (1.5 cm between sampling points). In most cases, significant vertical heterogeneity was observed at the 0.15 m scale, which was much larger than previously reported for freshwater wetlands and not detected by sampling water table wells screened over the same interval. However, profiles of ammonia and total phosphorus showed tenfold changes in the upper 0.2 meters of the saturated zone when sampled at the small (1.5 cm) scale, that was not depicted by sampling at the intermediate scale. At the intermediate scale of observation, one constructed wetland site differed geochemically from the natural wetlands and the other constructed wetland site due to application of off-site salvaged marsh surface and downward infiltration of rain. While important differences in dissolved inorganic phosphorus and dissolved inorganic carbon concentrations existed between the constructed wetland and the natural wetlands, we also observed substantial differences between the natural wetland sites for these constituents. A median-polishing analysis of our data showed that temporal variations in constituent concentrations within profiles, although extensively recognized in the literature, were not as important as spatial variability.","language":"English","publisher":"Springer","doi":"10.1023/A:1005889319205","issn":"01682563","usgsCitation":"Hunt, R.J., Krabbenhoft, D., and Anderson, M.P., 1997, Assessing hydrogeochemical heterogeneity in natural and constructed wetlands: Biogeochemistry, v. 39, no. 3, p. 271-293, https://doi.org/10.1023/A:1005889319205.","productDescription":"23 p.","startPage":"271","endPage":"293","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":206074,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1023/A:1005889319205"},{"id":228194,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059edd8e4b0c8380cd49a47","contributors":{"authors":[{"text":"Hunt, R. J.","contributorId":40164,"corporation":false,"usgs":true,"family":"Hunt","given":"R.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":385208,"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":385209,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Anderson, Marilyn P.","contributorId":102970,"corporation":false,"usgs":true,"family":"Anderson","given":"Marilyn","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":385210,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70019376,"text":"70019376 - 1997 - Regional interpretation of water-quality monitoring data","interactions":[],"lastModifiedDate":"2018-03-15T10:27:02","indexId":"70019376","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Regional interpretation of water-quality monitoring data","docAbstract":"We describe a method for using spatially referenced regressions of contaminant transport on watershed attributes (SPARROW) in regional water-quality assessment. The method is designed to reduce the problems of data interpretation caused by sparse sampling, network bias, and basin heterogeneity. The regression equation relates measured transport rates in streams to spatially referenced descriptors of pollution sources and land-surface and stream-channel characteristics. Regression models of total phosphorus (TP) and total nitrogen (TN) transport are constructed for a region defined as the nontidal conterminous United States. Observed TN and TP transport rates are derived from water-quality records for 414 stations in the National Stream Quality Accounting Network. Nutrient sources identified in the equations include point sources, applied fertilizer, livestock waste, nonagricultural land, and atmospheric deposition (TN only). Surface characteristics found to be significant predictors of land-water delivery include soil permeability, stream density, and temperature (TN only). Estimated instream decay coefficients for the two contaminants decrease monotonically with increasing stream size. TP transport is found to be significantly reduced by reservoir retention. Spatial referencing of basin attributes in relation to the stream channel network greatly increases their statistical significance and model accuracy. The method is used to estimate the proportion of watersheds in the conterminous United States (i.e., hydrologic cataloging units) with outflow TP concentrations less than the criterion of 0.1 mg/L, and to classify cataloging units according to local TN yield (kg/km2/yr).
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/97WR02171","usgsCitation":"Smith, R.A., Schwarz, G., and Alexander, R.B., 1997, Regional interpretation of water-quality monitoring data: Water Resources Research, v. 33, no. 12, p. 2781-2798, https://doi.org/10.1029/97WR02171.","productDescription":"18 p.","startPage":"2781","endPage":"2798","costCenters":[],"links":[{"id":480024,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/97wr02171","text":"Publisher Index Page"},{"id":226646,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"33","issue":"12","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"50e4a534e4b0e8fec6cdbd7b","contributors":{"authors":[{"text":"Smith, Richard A. 0000-0003-2117-2269 rsmith1@usgs.gov","orcid":"https://orcid.org/0000-0003-2117-2269","contributorId":580,"corporation":false,"usgs":true,"family":"Smith","given":"Richard","email":"rsmith1@usgs.gov","middleInitial":"A.","affiliations":[{"id":503,"text":"Office of Water Quality","active":true,"usgs":true},{"id":37778,"text":"WMA - Integrated Modeling and Prediction Division","active":true,"usgs":true},{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true}],"preferred":true,"id":382517,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schwarz, Gregory E. 0000-0002-9239-4566 gschwarz@usgs.gov","orcid":"https://orcid.org/0000-0002-9239-4566","contributorId":543,"corporation":false,"usgs":true,"family":"Schwarz","given":"Gregory E.","email":"gschwarz@usgs.gov","affiliations":[{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true},{"id":5067,"text":"Northeast Regional Director's Office","active":true,"usgs":true}],"preferred":false,"id":382516,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Alexander, Richard B. 0000-0001-9166-0626 ralex@usgs.gov","orcid":"https://orcid.org/0000-0001-9166-0626","contributorId":541,"corporation":false,"usgs":true,"family":"Alexander","given":"Richard","email":"ralex@usgs.gov","middleInitial":"B.","affiliations":[{"id":451,"text":"National Water Quality Assessment Program","active":true,"usgs":true},{"id":503,"text":"Office of Water Quality","active":true,"usgs":true}],"preferred":true,"id":382518,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70020143,"text":"70020143 - 1997 - Effect of nitrate, organic carbon, and temperature on potential denitrification rates in nitrate-rich riverbed sediments","interactions":[],"lastModifiedDate":"2012-03-12T17:19:18","indexId":"70020143","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Effect of nitrate, organic carbon, and temperature on potential denitrification rates in nitrate-rich riverbed sediments","docAbstract":"A study conducted in 1994 as part of the US Geological Survey's National Water-Quality Assessment Program, South Platte River Basin investigation, examined the effect of certain environmental factors on potential denitrification rates in nitrate-rich riverbed sediments. The acetylene block technique was used to measure nitrous oxide (N2O) production rates in laboratory incubations of riverbed sediments to evaluate the effect of varying nitrate concentrations, organic carbon concentrations and type, and water temperature on potential denitrification rates. Sediment incubations amended with nitrate, at concentrations ranging from 357 to 2142 ??mol l-1 (as measured in the field), produced no significant increase (P > 0.05) in N2O production rates, indicating that the denitrification potential in these sediments was not nitrate limited. In contrast, incubations amended with acetate as a source of organic carbon, at concentrations ranging from 0 to 624 ??mol l-1, produced significant increases (P < 0.05) in N2O production rates with increased organic carbon concentration, indicating that the denitrification potential in these sediments was organic carbon limited. Furthermore, N2O production rates also were affected by the type of organic carbon available as an electron donor. Acetate and surface-water-derived fulvic acid supported higher N2O production rates than groundwater-derived fulvic acid or sedimentary organic carbon. Lowering incubation temperatures from 22 to 4??C resulted in about a 77% decrease in the N2O production rates. These results help to explain findings from previous studies indicating that only 15-30% of nitrate in groundwater was denitrified before discharging to the South Platte River and that nitrate concentrations in the river generally were higher in winter than in summer.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0022-1694(96)03052-1","issn":"00221694","usgsCitation":"Pfenning, K., and McMahon, P., 1997, Effect of nitrate, organic carbon, and temperature on potential denitrification rates in nitrate-rich riverbed sediments: Journal of Hydrology, v. 187, no. 3-4, p. 283-295, https://doi.org/10.1016/S0022-1694(96)03052-1.","startPage":"283","endPage":"295","numberOfPages":"13","costCenters":[],"links":[{"id":206050,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(96)03052-1"},{"id":228077,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"187","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a05f6e4b0c8380cd51051","contributors":{"authors":[{"text":"Pfenning, K.S.","contributorId":49945,"corporation":false,"usgs":true,"family":"Pfenning","given":"K.S.","email":"","affiliations":[],"preferred":false,"id":385183,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"McMahon, P.B. 0000-0001-7452-2379","orcid":"https://orcid.org/0000-0001-7452-2379","contributorId":10762,"corporation":false,"usgs":true,"family":"McMahon","given":"P.B.","affiliations":[],"preferred":false,"id":385182,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70020142,"text":"70020142 - 1997 - Application of two direct runoff prediction methods in Puerto Rico","interactions":[],"lastModifiedDate":"2024-05-08T14:33:33.484403","indexId":"70020142","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2341,"text":"Journal of Hydrologic Engineering","active":true,"publicationSubtype":{"id":10}},"title":"Application of two direct runoff prediction methods in Puerto Rico","docAbstract":"Two methods for predicting direct runoff from rainfall data were applied to several basins and the resulting hydrographs compared to measured values. The first method uses a geomorphology-based unit hydrograph to predict direct runoff through its convolution with the excess rainfall hyetograph. The second method shows how the resulting hydraulic routing flow equation from a kinematic wave approximation is solved using a spectral method based on the matrix representation of the spatial derivative with Chebyshev collocation and a fourth-order Runge-Kutta time discretization scheme. The calibrated Green-Ampt (GA) infiltration parameters are obtained by minimizing the sum, over several rainfall events, of absolute differences between the total excess rainfall volume computed from the GA equations and the total direct runoff volume computed from a hydrograph separation technique. The improvement made in predicting direct runoff using a geomorphology-based unit hydrograph with the ephemeral and perennial stream network instead of the strictly perennial stream network is negligible. The hydraulic routing scheme presented here is highly accurate in predicting the magnitude and time of the hydrograph peak although the much faster unit hydrograph method also yields reasonable results.
","language":"English","publisher":"ASCE","doi":"10.1061/(ASCE)1084-0699(1997)2:1(10)","issn":"10840699","usgsCitation":"Sepulveda, N., 1997, Application of two direct runoff prediction methods in Puerto Rico: Journal of Hydrologic Engineering, v. 2, no. 1, p. 10-17, https://doi.org/10.1061/(ASCE)1084-0699(1997)2:1(10).","productDescription":"8 p.","startPage":"10","endPage":"17","numberOfPages":"8","costCenters":[],"links":[{"id":228042,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"2","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ecbfe4b0c8380cd49465","contributors":{"authors":[{"text":"Sepulveda, N.","contributorId":56805,"corporation":false,"usgs":true,"family":"Sepulveda","given":"N.","email":"","affiliations":[],"preferred":false,"id":385181,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020248,"text":"70020248 - 1997 - Physiological considerations in applying laboratory-determined buoyant densities to predictions of bacterial and protozoan transport in groundwater: Results of in-situ and laboratory tests","interactions":[],"lastModifiedDate":"2019-02-14T06:17:23","indexId":"70020248","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Physiological considerations in applying laboratory-determined buoyant densities to predictions of bacterial and protozoan transport in groundwater: Results of in-situ and laboratory tests","docAbstract":"Buoyant densities were determined for groundwater bacteria and microflagellates (protozoa) from a sandy aquifer (Cape Cod, MA) using two methods: (1) density-gradient centrifugation (DGC) and (2) Stoke's law approximations using sedimentation rates observed during natural-gradient injection and recovery tests. The dwarf (average cell size, 0.3 μm), unattached bacteria inhabiting a pristine zone just beneath the water table and a majority (∼80%) of the morphologically diverse community of free-living bacteria inhabiting a 5-km-long plume of organically-contaminated groundwater had DGC-determined buoyant densities <1.019 g/cm3 before culturing. In the aquifer, sinking rates for the uncultured 2-μm size class of contaminant plume bacteria were comparable to that of the bromide tracer (1.9 × 10-3 M), also suggesting a low buoyant density. Culturing groundwater bacteria resulted in larger (0.8−1.3 μm), less neutrally-buoyant (1.043−1.081 g/cm3) cells with potential sedimentation rates up to 64-fold higher than those predicted for the uncultured populations. Although sedimentation generally could be neglected in predicting subsurface transport for the community of free-living groundwater bacteria, it appeared to be important for the cultured isolates, at least until they readapt to aquifer conditions. Culturing-induced alterations in size of the contaminant-plume microflagellates (2−3 μm) were ameliorated by using a lower nutrient, acidic (pH 5) porous growth medium. Buoyant densities of the cultured microflagellates were low, i.e., 1.024−1.034 g/cm3 (using the DGC assay) and 1.017−1.039 g/cm3 (estimated from in-situ sedimentation rates), sug gesting good potential for subsurface transport under favorable conditions.
Data from a string of instrumented wells located on an upland of 55 m width between two wetlands in central North Dakota, USA, indicated frequent changes in water-table configuration following wet and dry periods during 5 years of investigation. A seasonal wetland is situated about 1.5 m higher than a nearby semipermanent wetland, suggesting an average ground water-table gradient of 0.02. However, water had the potential to flow as ground water from the upper to the lower wetland during only a few instances. A water-table trough adjacent to the lower semipermanent wetland was the most common water-table configuration during the first 4 years of the study, but it is likely that severe drought during those years contributed to the longevity and extent of the water-table trough. Water-table mounds that formed in response to rainfall events caused reversals of direction of flow that frequently modified the more dominant water-table trough during the severe drought. Rapid and large water-table rise to near land surface in response to intense rainfall was aided by the thick capillary fringe. One of the wettest summers on record ended the severe drought during the last year of the study, and caused a larger-scale water-table mound to form between the two wetlands. The mound was short in duration because it was overwhelmed by rising stage of the higher seasonal wetland which spilled into the lower wetland. Evapotranspiration was responsible for generating the water-table trough that formed between the two wetlands. Estimation of evapotranspiration based on diurnal fluctuations in wells yielded rates that averaged 3–5 mm day−1. On many occasions water levels in wells closer to the semipermanent wetland indicated a direction of flow that was different from the direction indicated by water levels in wells farther from the wetland. Misinterpretation of direction and magnitude of gradients between ground water and wetlands could result from poorly placed or too few observation wells, and also from infrequent measurement of water levels in wells.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0022-1694(96)03050-8","issn":"00221694","usgsCitation":"Rosenberry, D.O., and Winter, T.C., 1997, Dynamics of water-table fluctuations in an upland between two prairie-pothole wetlands in North Dakota: Journal of Hydrology, v. 191, no. 1-4, p. 266-289, https://doi.org/10.1016/S0022-1694(96)03050-8.","productDescription":"24 p.","startPage":"266","endPage":"289","numberOfPages":"24","costCenters":[{"id":478,"text":"North Dakota Water Science Center","active":true,"usgs":true},{"id":34685,"text":"Dakota Water Science Center","active":true,"usgs":true}],"links":[{"id":227786,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205992,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(96)03050-8"}],"volume":"191","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a043be4b0c8380cd5087a","contributors":{"authors":[{"text":"Rosenberry, Donald O. 0000-0003-0681-5641 rosenber@usgs.gov","orcid":"https://orcid.org/0000-0003-0681-5641","contributorId":1312,"corporation":false,"usgs":true,"family":"Rosenberry","given":"Donald","email":"rosenber@usgs.gov","middleInitial":"O.","affiliations":[{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true},{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":384972,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Winter, Thomas C.","contributorId":84736,"corporation":false,"usgs":true,"family":"Winter","given":"Thomas","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":384971,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019741,"text":"70019741 - 1997 - Agricultural chemicals in groundwater of the midwestern United States: Relations to land use","interactions":[],"lastModifiedDate":"2019-02-08T16:27:21","indexId":"70019741","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2262,"text":"Journal of Environmental Quality","active":true,"publicationSubtype":{"id":10}},"title":"Agricultural chemicals in groundwater of the midwestern United States: Relations to land use","docAbstract":"To determine the relations between land use and concentrations of selected agricultural chemicals (nitrate, atrazine residue [atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) + deethylatrazinc (2-amino-4-chloro-6-isopropylamino-s-triazine) + deisopropylatrazine (2-amino-4-chloro-6-ethylamino-s-triazine)], and alachlor residue [alachlor, [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide] + alachlor ethanesulfonic acid (alachlor-ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2-oxoethanesulfonic acid)] in groundwater, detailed land use information based on accurate measurements from aerial photographs for the 1991 growing season was obtained within a 2-km radius surrounding 100 wells completed in near-surface unconsolidated aquifers in the midwestern USA. The most significant land use factors to the agricultural chemicals examined were: nitrate (amount of irrigated crop production, positive relation), atrazine residue (amount of irrigated crop production, positive relation), and alachlor residue (amount of highly erodible land, inverse relation). The investigation of smaller buffer sizes (size of circular area around sampled wells) proved insightful for this study. Additional land use factors having significant relations to all three agricultural chemicals were identified using these smaller buffer radii. The most significant correlations (correlation maxima) generally occurred at ≤500-m for nitrate and ≥1000-m for atrazine residue and alachlor residue. An attempt to improve the statistical relations to land use by taking hydrologic considerations into account (removing land outside the estimated most probable recharge area from the statistical analysis) was not as successful as anticipated. Only 45% of the nitrate, 32% of the atrazine residue, and 20% of the alachlor residue correlations were improved by a consideration of the estimated most probable recharge area.
","language":"English","publisher":"ACSESS","doi":"10.2134/jeq1997.00472425002600040014x","issn":"00472425","usgsCitation":"Kolpin, D., 1997, Agricultural chemicals in groundwater of the midwestern United States: Relations to land use: Journal of Environmental Quality, v. 26, no. 4, p. 1025-1037, https://doi.org/10.2134/jeq1997.00472425002600040014x.","productDescription":"13 p.","startPage":"1025","endPage":"1037","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":351,"text":"Iowa Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":228019,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","volume":"26","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e912e4b0c8380cd48096","contributors":{"authors":[{"text":"Kolpin, D.W.","contributorId":87565,"corporation":false,"usgs":true,"family":"Kolpin","given":"D.W.","email":"","affiliations":[],"preferred":false,"id":383761,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019732,"text":"70019732 - 1997 - Multiphase flow modeling of a crude-oil spill site with a bimodal permeability distribution","interactions":[],"lastModifiedDate":"2019-02-13T05:48:05","indexId":"70019732","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Multiphase flow modeling of a crude-oil spill site with a bimodal permeability distribution","docAbstract":"Fluid saturation, particle-size distribution, and porosity measurements were obtained from 269 core samples collected from six boreholes along a 90-m transect at a subregion of a crude-oil spill site, the north pool, near Bemidji, Minnesota. The oil saturation data, collected 11 years after the spill, showed an irregularly shaped oil body that appeared to be affected by sediment spatial variability. The particle-size distribution data were used to estimate the permeability (k) and retention curves for each sample. An additional 344 k estimates were obtained from samples previously collected at the north pool. The 613 k estimates were distributed bimodal lognormally with the two population distributions corresponding to the two predominant lithologies: a coarse glacial outwash deposit and fine-grained interbedded lenses. A two-step geostatistical approach was used to generate a conditioned realization of k representing the bimodal heterogeneity. A cross-sectional multiphase flow model was used to simulate the flow of oil and water in the presence of air along the north pool transect for an 11-year period. The inclusion of a representation of the bimodal aquifer heterogeneity was crucial for reproduction of general features of the observed oil body. If the bimodal heterogeneity was characterized, hysteresis did not have to be incorporated into the model because a hysteretic effect was produced by the sediment spatial variability. By revising the relative permeability functional relation, an improved reproduction of the observed oil saturation distribution was achieved. The inclusion of water table fluctuations in the model did not significantly affect the simulated oil saturation distribution.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/97WR00857","usgsCitation":"Dillard, L.A., Essaid, H.I., and Herkelrath, W.N., 1997, Multiphase flow modeling of a crude-oil spill site with a bimodal permeability distribution: Water Resources Research, v. 33, no. 7, p. 1617-1632, https://doi.org/10.1029/97WR00857.","productDescription":"16 p.","startPage":"1617","endPage":"1632","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":480116,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/97wr00857","text":"Publisher Index Page"},{"id":227843,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"33","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a6057e4b0c8380cd713b3","contributors":{"authors":[{"text":"Dillard, Leslie A.","contributorId":189405,"corporation":false,"usgs":false,"family":"Dillard","given":"Leslie","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":383736,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Essaid, Hedeff I. 0000-0003-0154-8628 hiessaid@usgs.gov","orcid":"https://orcid.org/0000-0003-0154-8628","contributorId":2284,"corporation":false,"usgs":true,"family":"Essaid","given":"Hedeff","email":"hiessaid@usgs.gov","middleInitial":"I.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":383735,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Herkelrath, William N. 0000-0002-6149-5524 wnherkel@usgs.gov","orcid":"https://orcid.org/0000-0002-6149-5524","contributorId":2612,"corporation":false,"usgs":true,"family":"Herkelrath","given":"William","email":"wnherkel@usgs.gov","middleInitial":"N.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":383737,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70019730,"text":"70019730 - 1997 - Evaluation of unconfined-aquifer parameters from pumping test data by nonlinear least squares","interactions":[],"lastModifiedDate":"2019-02-13T06:15:40","indexId":"70019730","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Evaluation of unconfined-aquifer parameters from pumping test data by nonlinear least squares","docAbstract":"Nonlinear least squares (NLS) with automatic differentiation was used to estimate aquifer parameters from drawdown data obtained from published pumping tests conducted in homogeneous, water-table aquifers. The method is based on a technique that seeks to minimize the squares of residuals between observed and calculated drawdown subject to bounds that are placed on the parameter of interest. The analytical model developed by Neuman for flow to a partially penetrating well of infinitesimal diameter situated in an infinite, homogeneous and anisotropic aquifer was used to obtain calculated drawdown. NLS was first applied to synthetic drawdown data from a hypothetical but realistic aquifer to demonstrate that the relevant hydraulic parameters (storativity, specific yield, and horizontal and vertical hydraulic conductivity) can be evaluated accurately. Next the method was used to estimate the parameters at three field sites with widely varying hydraulic properties. NLS produced unbiased estimates of the aquifer parameters that are close to the estimates obtained with the same data using a visual curve-matching approach. Small differences in the estimates are a consequence of subjective interpretation introduced in the visual approach.","language":"English","publisher":"Elsevier","doi":"10.1016/S0022-1694(96)03101-0","issn":"00221694","usgsCitation":"Heidari, M., and Moench, A., 1997, Evaluation of unconfined-aquifer parameters from pumping test data by nonlinear least squares: Journal of Hydrology, v. 192, no. 1-4, p. 300-313, https://doi.org/10.1016/S0022-1694(96)03101-0.","productDescription":"14 p.","startPage":"300","endPage":"313","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":227805,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205998,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(96)03101-0"}],"volume":"192","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0d02e4b0c8380cd52dac","contributors":{"authors":[{"text":"Heidari, M.","contributorId":26430,"corporation":false,"usgs":true,"family":"Heidari","given":"M.","email":"","affiliations":[],"preferred":false,"id":383731,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Moench, A.","contributorId":12638,"corporation":false,"usgs":true,"family":"Moench","given":"A.","email":"","affiliations":[],"preferred":false,"id":383730,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019716,"text":"70019716 - 1997 - Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer","interactions":[],"lastModifiedDate":"2019-02-13T06:20:46","indexId":"70019716","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1621,"text":"FEMS Microbiology Reviews","active":true,"publicationSubtype":{"id":10}},"title":"Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer","docAbstract":"Little is known about the role of protists in the saturated subsurface. Porous media microcosms containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free- living bacteria (FLB). When flagellates were present, the 3-40% maximum breakthrough of fluorescent y labelled FLB injected into the microcosms was much lower than the 60-130% observed for killed controls Grazing and clearance rates (3-27 FLB flag-1 h-1 and 12-23 nI flag-1 h-1, respectively) calculated from the data were in the range reported for flagellates in other aqueous environments. The data provide evidence that flagellate bacterivory is an important control on groundwater FLB populations.","language":"English","publisher":"Oxford","doi":"10.1016/S0168-6445(97)00011-9","issn":"01686445","usgsCitation":"Kinner, N., Harvey, R., and Kazmierkiewicz-Tabaka, M., 1997, Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer: FEMS Microbiology Reviews, v. 20, no. 3-4, p. 249-259, https://doi.org/10.1016/S0168-6445(97)00011-9.","productDescription":"11 p.","startPage":"249","endPage":"259","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":480034,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1016/s0168-6445(97)00011-9","text":"Publisher Index Page"},{"id":228288,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206098,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0168-6445(97)00011-9"}],"volume":"20","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a05dee4b0c8380cd50fd5","contributors":{"authors":[{"text":"Kinner, N.E.","contributorId":29583,"corporation":false,"usgs":true,"family":"Kinner","given":"N.E.","email":"","affiliations":[],"preferred":false,"id":383693,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Harvey, R.W. 0000-0002-2791-8503","orcid":"https://orcid.org/0000-0002-2791-8503","contributorId":11757,"corporation":false,"usgs":true,"family":"Harvey","given":"R.W.","affiliations":[],"preferred":false,"id":383691,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kazmierkiewicz-Tabaka, M.","contributorId":20923,"corporation":false,"usgs":true,"family":"Kazmierkiewicz-Tabaka","given":"M.","email":"","affiliations":[],"preferred":false,"id":383692,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70019703,"text":"70019703 - 1997 - 222Rn transport in a fractured crystalline rock aquifer: Results from numerical simulations","interactions":[],"lastModifiedDate":"2012-03-12T17:19:20","indexId":"70019703","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"222Rn transport in a fractured crystalline rock aquifer: Results from numerical simulations","docAbstract":"Dissolved 222Rn concentrations in ground water from a small wellfield underlain by fractured Middle Proterozoic Pikes Peak Granite southwest of Denver, Colorado range from 124 to 840 kBq m-3 (3360-22700 pCi L-1). Numerical simulations of flow and transport between two wells show that differences in equivalent hydraulic aperture of transmissive fractures, assuming a simplified two-fracture system and the parallel-plate model, can account for the different 222Rn concentrations in each well under steady-state conditions. Transient flow and transport simulations show that 222Rn concentrations along the fracture profile are influenced by 222Rn concentrations in the adjoining fracture and depend on boundary conditions, proximity of the pumping well to the fracture intersection, transmissivity of the conductive fractures, and pumping rate. Non-homogeneous distribution (point sources) of 222Rn parent radionuclides, uranium and 226Ra, can strongly perturb the dissolved 222Rn concentrations in a fracture system. Without detailed information on the geometry and hydraulic properties of the connected fracture system, it may be impossible to distinguish the influence of factors controlling 222Rn distribution or to determine location of 222Rn point sources in the field in areas where ground water exhibits moderate 222Rn concentrations. Flow and transport simulations of a hypothetical multifracture system consisting of ten connected fractures, each 10 m in length with fracture apertures ranging from 0.1 to 1.0 mm, show that 222Rn concentrations at the pumping well can vary significantly over time. Assuming parallel-plate flow, transmissivities of the hypothetical system vary over four orders of magnitude because transmissivity varies with the cube of fracture aperture. The extreme hydraulic heterogeneity of the simple hypothetical system leads to widely ranging 222Rn values, even assuming homogeneous distribution of uranium and 226Ra along fracture walls. Consequently, it is concluded that 222Rn concentrations vary, not only with the geometric and stress factors noted above, but also according to local fracture aperture distribution, local groundwater residence time, and flux of 222Rn from parent radionuclides along fracture walls.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0022-1694(96)03243-X","issn":"00221694","usgsCitation":"Folger, P.F., Poeter, E., Wanty, R., Day, W., and Frishman, D., 1997, 222Rn transport in a fractured crystalline rock aquifer: Results from numerical simulations: Journal of Hydrology, v. 195, no. 1-4, p. 45-77, https://doi.org/10.1016/S0022-1694(96)03243-X.","startPage":"45","endPage":"77","numberOfPages":"33","costCenters":[],"links":[{"id":206052,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0022-1694(96)03243-X"},{"id":228091,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"195","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e252e4b0c8380cd45ab1","contributors":{"authors":[{"text":"Folger, P. F.","contributorId":57862,"corporation":false,"usgs":true,"family":"Folger","given":"P.","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":383649,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Poeter, E.","contributorId":48708,"corporation":false,"usgs":true,"family":"Poeter","given":"E.","affiliations":[],"preferred":false,"id":383648,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wanty, R. B. 0000-0002-2063-6423","orcid":"https://orcid.org/0000-0002-2063-6423","contributorId":66704,"corporation":false,"usgs":true,"family":"Wanty","given":"R. B.","affiliations":[],"preferred":false,"id":383650,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Day, W. 0000-0002-9278-2120","orcid":"https://orcid.org/0000-0002-9278-2120","contributorId":72136,"corporation":false,"usgs":true,"family":"Day","given":"W.","affiliations":[],"preferred":false,"id":383651,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Frishman, D.","contributorId":14959,"corporation":false,"usgs":true,"family":"Frishman","given":"D.","affiliations":[],"preferred":false,"id":383647,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70019687,"text":"70019687 - 1997 - A watershed approach to ecosystem monitoring in Denali National Park and preserve, Alaska","interactions":[],"lastModifiedDate":"2024-05-29T23:16:31.807351","indexId":"70019687","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"A watershed approach to ecosystem monitoring in Denali National Park and preserve, Alaska","docAbstract":"The National Park Service and the National Biological Service initiated research in Denali National Park and Preserve, a 2.4 million-hectare park in southcentral Alaska, to develop ecological monitoring protocols for national parks in the Arctic/Subarctic biogeographic area. We are focusing pilot studies on design questions, on scaling issues and regionalization, ecosystem structure and function, indicator selection and evaluation, and monitoring technologies. Rock Creek, a headwater stream near Denali headquarters, is the ecological scale for initial testing of a watershed ecosystem approach. Our conceptual model embraces principles of the hydrological cycle, hypotheses of global climate change, and biological interactions of organisms occupying intermediate, but poorly studied, positions in Alaskan food webs. The field approach includes hydrological and depositional considerations and a suite of integrated measures linking key aquatic and terrestrial biota, environmental variables, or defined ecological processes, in order to establish ecological conditions and detect, track, and understand mechanisms of environmental change. Our sampling activities include corresponding measures of physical, chemical, and biological attributes in four Rock Creek habitats believed characteristic of the greater system diversity of Denali. This paper gives examples of data sets, program integration and scaling, and research needs.","language":"English","publisher":"American Water Resources Association","doi":"10.1111/j.1752-1688.1997.tb04106.x","issn":"1093474X","usgsCitation":"Thorsteinson, L., and Taylor, D., 1997, A watershed approach to ecosystem monitoring in Denali National Park and preserve, Alaska: Journal of the American Water Resources Association, v. 33, no. 4, p. 795-810, https://doi.org/10.1111/j.1752-1688.1997.tb04106.x.","productDescription":"16 p.","startPage":"795","endPage":"810","numberOfPages":"16","costCenters":[],"links":[{"id":227801,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"33","issue":"4","noUsgsAuthors":false,"publicationDate":"2007-06-08","publicationStatus":"PW","scienceBaseUri":"5059e61ce4b0c8380cd4717d","contributors":{"authors":[{"text":"Thorsteinson, L.K.","contributorId":100131,"corporation":false,"usgs":true,"family":"Thorsteinson","given":"L.K.","email":"","affiliations":[],"preferred":false,"id":383596,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Taylor, D.L.","contributorId":50676,"corporation":false,"usgs":true,"family":"Taylor","given":"D.L.","email":"","affiliations":[],"preferred":false,"id":383595,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019672,"text":"70019672 - 1997 - Effects of carbon dioxide variations in the unsaturated zone on water chemistry in a glacial-outwash aquifer","interactions":[],"lastModifiedDate":"2019-02-14T06:21:28","indexId":"70019672","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Effects of carbon dioxide variations in the unsaturated zone on water chemistry in a glacial-outwash aquifer","docAbstract":"The research site at Otis Air Base, Cape Cod, Massachusetts, has been developed for hydrogeological and geochemical studies of sewage-effluent contaminated groundwater since 1982. Research of hydrologic properties, transport, and chemical and biological processes is ongoing, but the origin of background water chemistry has not been determined. The principal geochemical process giving rise to the observed background water chemistry is CO2-controlled hydrolysis of Na feldspar. Geochemical modeling demonstrated that CO2 sources could vary over the project area. Analyses of unsaturated zone gases showed variations in CO2 which were dependent on land use and vegetative cover in the area of groundwater recharge. Measurements of CO2 in unsaturated-zone gases showed that concentrations of total inorganic C in recharge water should range from about 0.035 to 1.0 mmoles/L in the vicinity of Otis Air Base. Flux of CO2 from the unsaturated zone varied for a principal land uses, ranging from 86 gC/m2/yr for low vegetated areas to 1630 gC/m2/yr for a golf course. Carbon dioxide flux from woodlands was 220 gC/m2/yr, lower than reported fluxes of 500 to 600 gC/m2/yr for woodlands in a similar climate. Carbon dioxide flux from grassy areas was 540 gC/m2/yr, higher than reported fluxes of 230 to 490 gC/m2/yr for grasslands in a similar climate.","language":"English","publisher":"Elsevier","doi":"10.1016/S0883-2927(97)00001-2","issn":"08832927","usgsCitation":"Lee, R.W., 1997, Effects of carbon dioxide variations in the unsaturated zone on water chemistry in a glacial-outwash aquifer: Applied Geochemistry, v. 12, no. 4, p. 347-366, https://doi.org/10.1016/S0883-2927(97)00001-2.","productDescription":"20 p.","startPage":"347","endPage":"366","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":206069,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0883-2927(97)00001-2"},{"id":228170,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"12","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a06a4e4b0c8380cd51352","contributors":{"authors":[{"text":"Lee, R. W.","contributorId":86757,"corporation":false,"usgs":true,"family":"Lee","given":"R.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":383513,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019669,"text":"70019669 - 1997 - Soil-water movement under natural-site and waste-site conditions: A multiple-year field study in the Mojave Desert, Nevada","interactions":[],"lastModifiedDate":"2019-02-04T10:43:39","indexId":"70019669","displayToPublicDate":"1997-01-01T00:00:00","publicationYear":"1997","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":"Soil-water movement under natural-site and waste-site conditions: A multiple-year field study in the Mojave Desert, Nevada","docAbstract":"Soil-water movement under natural-site and simulated waste-site conditions were compared by monitoring four experimental sites in the Mojave Desert, Nevada, during a 5-year period: one vegetated soil profile, one soil profile where vegetation was removed, and two nonvegetated test trenches. Precipitation ranged from 14 to 162 mm/yr. Temporal changes in water content measured by neutron probe were limited to the upper 0.5–1 m; values ranged from 0.01 to 0.19 m3/m3. Water potential and temperature were measured by thermocouple psychrometers; 77% remained operable for ≥4.5 years. For vegetated soil, precipitation that accumulated in the upper 0.75 m of soil was removed by evapotranspiration: water potentials decreased seasonally by 4 to >8 MPa. During 2 years with below-average precipitation, water potentials below the app arent root zone decreased by 2.3 (1.2-m depth) to 0.4 MPa (5-m depth), and the gradients became predominantly upward. Water potentials then rebounded during 2 years with near- and above-average precipitation, and seasonally variant water potential gradients were reestablished above the 4.2-m depth. Under nonvegetated waste-site conditions, data indicated the long-term accumulation and shallow, but continued, penetration of precipitation: water potentials showed moisture penetration to depths of 0.75−1.85 m. The method of simulated-waste drum placement (stacked versus random) and the associated differences in subsidence showed no measurable influence on the water balance of the trenches: subsidence totaled ≤13 mm during the study. Water potentials below the trenches and below the 2-m depth for the nonvegetated soil remained low (≈−5.5 to −7.5 MPa) and indicated the persistence of typically upward driving forces for isothermal water flow. Water fluxes estimated from water potential and temperature data suggested that isothermal liquid, isothermal vapor, and nonisothermal vapor flow need to be considered in the conceptualization of unsaturated flow at the field sites. Below the depth of temporal water content change, the estimated liquid fluxes ranged from 10−10 to 10−15 cm/s, isothermal vapor fluxes ranged from 10−10 to 10−13 cm/s, and the nonisothermal vapor fluxes ranged from 10−8 to 10−10cm/s.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/97WR01502","usgsCitation":"Andraski, B.J., 1997, Soil-water movement under natural-site and waste-site conditions: A multiple-year field study in the Mojave Desert, Nevada: Water Resources Research, v. 33, no. 8, p. 1901-1916, https://doi.org/10.1029/97WR01502.","productDescription":"16 p.","startPage":"1901","endPage":"1916","costCenters":[{"id":465,"text":"Nevada Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":480058,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/97wr01502","text":"Publisher Index Page"},{"id":228130,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Nevada","otherGeospatial":"Mojave Desert","volume":"33","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b922ce4b08c986b319d44","contributors":{"authors":[{"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":38175,"text":"Toxics Substances Hydrology Program","active":true,"usgs":true},{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true},{"id":465,"text":"Nevada Water Science Center","active":true,"usgs":true}],"preferred":false,"id":383508,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ]}