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Sample records for implicate surface water

  1. Assessing metaldehyde concentrations in surface water catchments and implications for drinking water abstraction

    NASA Astrophysics Data System (ADS)

    Asfaw, Alemayehu; Shucksmith, James; Smith, Andrea; Cherry, Katherine

    2015-04-01

    Metaldehyde is an active ingredient in agricultural pesticides such as slug pellets, which are heavily applied to UK farmland during the autumn application season. There is current concern that existing drinking water treatment processes may be inadequate in reducing potentially high levels of metaldehyde in surface waters to below the UK drinking water quality regulation limit of 0.1 µg/l. In addition, current water quality monitoring methods can miss short term fluctuations in metaldehyde concentration caused by rainfall driven runoff, hampering prediction of the potential risk of exposure. Datasets describing levels, fate and transport of metaldehyde in river catchments are currently very scarce. This work presents results from an ongoing study to quantify the presence of metaldehyde in surface waters within a UK catchment used for drinking water abstraction. High resolution water quality data from auto-samplers installed in rivers are coupled with radar rainfall, catchment characteristics and land use data to i) understand which hydro-meteorological characteristics of the catchment trigger the peak migration of metaldehyde to surface waters; ii) assess the relationship between measured metaldehyde levels and catchment characteristics such as land use, topographic index, proximity to water bodies and runoff generation area; iii) describe the current risks to drinking water supply and discuss mitigation options based on modelling and real-time control of water abstraction. Identifying the correlation between catchment attributes and metaldehyde generation will help in the development of effective catchment management strategies, which can help to significantly reduce the amount of metaldehyde finding its way into river water. Furthermore, the effectiveness of current water quality monitoring strategy in accurately quantifying the generation of metaldehyde from the catchment and its ability to benefit the development of effective catchment management practices

  2. Groundwater and surface water discharge from an abandoned tailings impoundment: Implications for watershed water quality

    NASA Astrophysics Data System (ADS)

    Moncur, M. C.; Ptacek, C. J.; Blowes, D. W.; Birks, S. J.

    2006-12-01

    Release of acid drainage from mine-waste disposal areas is a problem of international scale. Drainage from sulfide-rich waste can result in contaminated surface waters, directly through surface runoff and indirectly, from discharge of contaminated groundwater flow. Camp Lake, located in Northern Manitoba, receives both direct and indirect drainage from an abandoned tailings impoundment, which has severely affected the quality of the downstream watershed. Nearly a century of sulfide oxidation at this mine site has resulted in extremely high concentrations of oxidation products in the surface water and groundwater discharging from the two tailings impoundments, both of which flow into an adjacent semi-isolated shallow bay in Camp Lake. The incorporation of these aqueous effluents has altered the composition of the lake water, which in turn has modified the physical limnology of the lake. The various sources of water and solutes to the lake (surface inflows, perched water table, primary water table) contribute varying concentrations of metals to the overall contaminant loadings to the lake, and can be characterized by distinct 3H, δ18O, and δ2H compositions. Geochemical profiles of the water column indicate that, despite its shallow depth (6 m), the bay is stratified throughout the year. The greatest accumulation of dissolved metals and SO4 is in the lower portion of the water column, with concentrations up to 8500 mg/L Fe, 20,000 mg/L SO4, 30 mg/L Zn, and 100 mg/L Al, including elevated concentrations of Cu, Cd, Pb, and Ni. This stratification is mirrored in the δ18O, δ2H and d-excess profiles within the lake water column, with an evaporatively enriched surface layer overlying the isotopically lighter, higher d-excess hypolimnion. Despite meromictic conditions and very high solute concentrations being limited to the semi-isolated bay, the annual loadings of acid, sulfate, and metals from Camp Lake to the adjacent lake are extremely large, and fluctuate seasonally

  3. Geochemical characterization of surface water and spring water in SE Kashmir Valley, western Himalaya: Implications to water-rock interaction

    NASA Astrophysics Data System (ADS)

    Jeelani, Gh; Bhat, Nadeem A.; Shivanna, K.; Bhat, M. Y.

    2011-10-01

    Water samples from precipitation, glacier melt, snow melt, glacial lake, streams and karst springs were collected across SE of Kashmir Valley, to understand the hydrogeochemical processes governing the evolution of the water in a natural and non-industrial area of western Himalayas. The time series data on solute chemistry suggest that the hydrochemical processes controlling the chemistry of spring waters is more complex than the surface water. This is attributed to more time available for infiltrating water to interact with the diverse host lithology. Total dissolved solids (TDS), in general, increases with decrease in altitude. However, high TDS of some streams at higher altitudes and low TDS of some springs at lower altitudes indicated contribution of high TDS waters from glacial lakes and low TDS waters from streams, respectively. The results show that some karst springs are recharged by surface water; Achabalnag by the Bringi stream and Andernag and Martandnag by the Liddar stream. Calcite dissolution, dedolomitization and silicate weathering were found to be the main processes controlling the chemistry of the spring waters and calcite dissolution as the dominant process in controlling the chemistry of the surface waters. The spring waters were undersaturated with respect to calcite and dolomite in most of the seasons except in November, which is attributed to the replenishment of the CO2 by recharging waters during most of the seasons.

  4. Adsorption of CO on oxide and water ice surfaces - Implications for the Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Leu, M.-T.; Blamont, J. E.; Anbar, A. D.; Keyser, L. F.; Sander, S. P.

    1992-01-01

    The adsorption of carbon monoxide (CO) on water ice and on the oxides Fe2O3, Fe3O4, Al2O3, SiO2, CaO, MgO, and TiO2 (rutile and anatase) has been investigated in a flow reactor. A mass spectrometer was employed as a detector to monitor the temporal concentrations of CO. Adsorption coefficients as large as 1 x 10 exp -4 were measured for CO on TiO2 solids in helium at 196 K. The fractional surface coverage for CO on TiO2 solids in helium was also determined to be approximately 10 percent at 196 K. The upper limits of the fractional surface coverage for the other oxides (Fe2O3, Fe3O4, Al2O3, SiO2, CaO, and MgO) and water ice were also measured to be less than 1 percent. The implications for the stability of CO2 in the Martian atmosphere and the 'CO hole' observed by the Phobos/ISM experiment are discussed.

  5. The effects of steam on the surface properties of palygorskite: Implications for palygorskite-water interactions

    NASA Astrophysics Data System (ADS)

    Kadakia, Abhy

    decreased by 40-50% after steam treatment. The reduced affinity for water and EGME may represent a reduced affinity for polar molecules in general. These results, particularly the XPS spectra and the observed large changes in rheological properties, suggest that steam altered the H + ion environment and/or concentration on palygorskite's surface. Exposing palygorskite to steam may have significant implications for its industrial applications, adversely affecting some applications and enhancing others.

  6. Ceres: predictions for near-surface water ice stability and implications for plume generating processes

    USGS Publications Warehouse

    Titus, Timothy N.

    2015-01-01

    This paper will constrain the possible sources and processes for the formation of recently observed H2O vapor plumes above the surface of the dwarf planet Ceres. Two hypotheses have been proposed: (1) cryovolcanism where the water source is the mantle and the heating source is still unknown or (2) comet-like sublimation where near-surface water ice is vaporized by seasonally increasing solar insolation. We test hypothesis #2, comet-like near-surface sublimation, by using a thermal model to examine the stability of water-ice in the near surface. For a reasonable range of physical parameters (thermal inertia, surface roughness, slopes), we find that water ice is only stable at latitudes higher than ~40-60 degrees. These results indicate that either (a) the physical properties of Ceres are unlike our expectations or (b) an alternative to comet-like sublimation, such as the cryovolcanism hypothesis, must be invoked.

  7. Water organization between oppositely charged surfaces: Implications for protein sliding along DNA a)

    NASA Astrophysics Data System (ADS)

    Marcovitz, Amir; Naftaly, Aviv; Levy, Yaakov

    2015-02-01

    Water molecules are abundant in protein-DNA interfaces, especially in their nonspecific complexes. In this study, we investigated the organization and energetics of the interfacial water by simplifying the geometries of the proteins and the DNA to represent them as two equally and oppositely charged planar surfaces immersed in water. We found that the potential of mean force for bringing the two parallel surfaces into close proximity comprises energetic barriers whose properties strongly depend on the charge density of the surfaces. We demonstrated how the organization of the water molecules into discretized layers and the corresponding energetic barriers to dehydration can be modulated by the charge density on the surfaces, salt, and the structure of the surfaces. The 1-2 layers of ordered water are tightly bound to the charged surfaces representing the nonspecific protein-DNA complex. This suggests that water might mediate one-dimensional diffusion of proteins along DNA (sliding) by screening attractive electrostatic interactions between the positively charged molecular surface on the protein and the negatively charged DNA backbone and, in doing so, reduce intermolecular friction in a manner that smoothens the energetic landscape for sliding, and facilitates the 1D diffusion of the protein.

  8. GROUNDWATER-SURFACE WATER EXCHANGE AND IMPLICATIONS FOR LARGE RIVER RESTORATION

    EPA Science Inventory

    Movement of river water into and out of high-porosity alluvial deposits can have an important influence on surface water quality and aquatic habitat. In our study of a 60-km reach of the Willamette River in Oregon, USA, we: 1) used tracers to estimate the rate of exchange betw...

  9. GROUNDWATER-SURFACE WATER EXCHANGE AND IMPLICATIONS FOR LARGE RIVER RESTORATION

    EPA Science Inventory

    Movement of river water into and out of high-porosity alluvial deposits can have an important influence on surface water quality and aquatic habitat. In our study of a 60-km reach of the Willamette River in Oregon, USA, we: 1) used tracers to estimate the rate of exchange betw...

  10. The Association of Cryptosporidium parvum With Suspended Sediments: Implications for Transport in Surface Waters

    NASA Astrophysics Data System (ADS)

    Searcy, K. E.; Packman, A. I.; Atwill, E. R.; Harter, T.

    2003-12-01

    Understanding the transport and fate of microorganisms in surface waters is of vital concern in protecting the integrity and safety of municipal water supply systems. The human pathogen Cryptosporidium parvum is a particular public health interest, as it is ubiquitous in the surface waters of the United States, it can persist for long periods in the environment, and it is difficult to disinfect in water treatment plants. Due to its small size (5 um), low specific gravity (1.05 g/cm3), and negative surface charge, C. parvum oocysts are generally considered to move through watersheds from their source to drinking water reservoirs with little attenuation. However, the transport of the oocysts in surface waters may be mediated by interactions with suspended sediments. Batch experiments were conducted to determine the extent of C. parvum oocyst attachment to several inorganic and organic sediments under varying water chemical conditions, and settling column experiments were performed to demonstrate how these associations influence the effective settling velocity of C. parvum oocysts. Results from these experiments showed that C. parvum oocysts do associate with inorganic and organic sediments and often settle at the rate of the suspended sediment. The size and surface charge of the host suspended sediment influenced the extent of oocyst attachment as oocysts preferentially associated with particles greater than 3 um, and fewer oocysts associated with particles having a highly negative surface charge. Background water chemical conditions including ionic strength, ion composition, and pH did not have a significant effect on oocyst attachment to suspended sediments.

  11. On the implications of the Surface Water and Ocean Topography (SWOT) mission for hydrologic science and applications (Invited)

    NASA Astrophysics Data System (ADS)

    Lettenmaier, D. P.

    2010-12-01

    The SWOT mission will provide surface water elevation and extent information with unprecedented accuracy and spatial resolution globally. All of the implications of thedata that SWOT will produce for the hydrologic science and applications communities are not yet apparent. The SWOT data will, however, certainly offer groundbreaking opportunities for estimation of two key terms in the land surface water budget: surface water storage (in almost all water bodies with surface area exceeding about 1 km2) and derived discharge for many of the world’s large rivers (widths greater than roughly 100-250 m). Among just a few of the science questions that the observations should allow us to address are a) what are the dynamics of floods and overbank flows in large rivers? b) what is the contribution of long-term, seasonal, and interannual storage in reservoirs, lakes, and wetlands to sea level? c) what is the magnitude of surface water storage changes at seasonal to decadal time scales and continental spatial scales relative to soil moisture and groundwater? d) what will be the implications of SWOT-based estimates of reservoir storage and storage change to the management of transboundary rivers? These quite likely are among just a few of the questions that SWOT will help elucidate. Others no doubt will arise from creative analyses of SWOT data in combination with data from other missions I conclude with a discussion of mechanisms that will help foster a community to investigate these and other questions, and the implications of a SWOT data policy.

  12. Virtual mission stage I: Implications of a spaceborne surface water mission

    NASA Astrophysics Data System (ADS)

    Clark, E. A.; Alsdorf, D. E.; Bates, P.; Wilson, M. D.; Lettenmaier, D. P.

    2004-12-01

    The interannual and interseasonal variability of the land surface water cycle depend on the distribution of surface water in lakes, wetlands, reservoirs, and river systems; however, measurements of hydrologic variables are sparsely distributed, even in industrialized nations. Moreover, the spatial extent and storage variations of lakes, reservoirs, and wetlands are poorly known. We are developing a virtual mission to demonstrate the feasibility of observing surface water extent and variations from a spaceborne platform. In the first stage of the virtual mission, on which we report here, surface water area and fluxes are emulated using simulation modeling over three continental scale river basins, including the Ohio River, the Amazon River and an Arctic river. The Variable Infiltration Capacity (VIC) macroscale hydrologic model is used to simulate evapotranspiration, soil moisture, snow accumulation and ablation, and runoff and streamflow over each basin at one-eighth degree resolution. The runoff from this model is routed using a linear transfer model to provide input to a much more detailed flow hydraulics model. The flow hydraulics model then routes runoff through various channel and floodplain morphologies at a 250 m spatial and 20 second temporal resolution over a 100 km by 500 km domain. This information is used to evaluate trade-offs between spatial and temporal resolutions of a hypothetical high resolution spaceborne altimeter by synthetically sampling the resultant model-predicted water surface elevations.

  13. Spatiotemporal dynamics of surface water networks across a global biodiversity hotspot—implications for conservation

    NASA Astrophysics Data System (ADS)

    Tulbure, Mirela G.; Kininmonth, Stuart; Broich, Mark

    2014-11-01

    The concept of habitat networks represents an important tool for landscape conservation and management at regional scales. Previous studies simulated degradation of temporally fixed networks but few quantified the change in network connectivity from disintegration of key features that undergo naturally occurring spatiotemporal dynamics. This is particularly of concern for aquatic systems, which typically show high natural spatiotemporal variability. Here we focused on the Swan Coastal Plain, a bioregion that encompasses a global biodiversity hotspot in Australia with over 1500 water bodies of high biodiversity. Using graph theory, we conducted a temporal analysis of water body connectivity over 13 years of variable climate. We derived large networks of surface water bodies using Landsat data (1999-2011). We generated an ensemble of 278 potential networks at three dispersal distances approximating the maximum dispersal distance of different water dependent organisms. We assessed network connectivity through several network topology metrics and quantified the resilience of the network topology during wet and dry phases. We identified ‘stepping stone’ water bodies across time and compared our networks with theoretical network models with known properties. Results showed a highly dynamic seasonal pattern of variability in network topology metrics. A decline in connectivity over the 13 years was noted with potential negative consequences for species with limited dispersal capacity. The networks described here resemble theoretical scale-free models, also known as ‘rich get richer’ algorithm. The ‘stepping stone’ water bodies are located in the area around the Peel-Harvey Estuary, a Ramsar listed site, and some are located in a national park. Our results describe a powerful approach that can be implemented when assessing the connectivity for a particular organism with known dispersal distance. The approach of identifying the surface water bodies that act as

  14. Temperature Dependence of Cryogenic Ammonia-Water Ice Mixtures and Implications for Icy Satellite Surfaces

    NASA Technical Reports Server (NTRS)

    Dalton, J. B., III; Curchin, J. M.; Clark, R. N.

    2001-01-01

    Infrared spectra of ammonia-water ice mixtures reveal temperature-dependent absorption bands due to ammonia. These features, at 1.04, 2.0, and 2.25 microns, may shed light on the surface compositions of the Galilean and Saturnian satellites. Additional information is contained in the original extended abstract.

  15. Temperature Dependence of Cryogenic Ammonia-Water Ice Mixtures and Implications for Icy Satellite Surfaces

    NASA Technical Reports Server (NTRS)

    Dalton, J. B., III; Curchin, J. M.; Clark, R. N.

    2001-01-01

    Infrared spectra of ammonia-water ice mixtures reveal temperature-dependent absorption bands due to ammonia. These features, at 1.04, 2.0, and 2.25 microns, may shed light on the surface compositions of the Galilean and Saturnian satellites. Additional information is contained in the original extended abstract.

  16. Evaporative Control on Soil Water Isotope Ratios: Implications for Atmosphere-Land Surface Water Fluxes and Interpretation of Terrestrial Proxy Records

    NASA Astrophysics Data System (ADS)

    Kaushik, A.; Noone, D. C.; Berkelhammer, M. B.; O'Neill, M.

    2014-12-01

    model at the land surface to weight the contributions of rainfall, surface water vapor exchange and sub-surface vapor diffusion to soil water isotope values. This has implications both for modeling short-term gas exchange at the land surface as well as for estimating past evaporative conditions from proxies like cave deposits and tree cellulose.

  17. Multiscale controls on water surface roughness and implications for remote sensing of rivers

    NASA Astrophysics Data System (ADS)

    Overstreet, B. T.; Legleiter, C. J.; Harrison, L.; Pitcher, L. H.; Ryan, J.; Rennermalm, A. K.; Smith, L. C.

    2015-12-01

    Remote sensing has emerged as a viable and efficient tool for studying river systems and facilitating their rehabilitation. While many remote sensing applications utilize spectral information from the substrate and water column, light reflected from the water surface is often a significant component of the total at-sensor radiance. As water surface roughness (WSR) increases, a greater proportion of surface facets become oriented so as to reflect, rather than transmit, light. As a result, WSR exerts a primary control on the amount of surface reflected light measured by a remote sensor. WSR in rivers is a function of flow hydraulics, channel form, slope, bed roughness, and wind. While the relative influence of each of these components on WSR changes with scale, understanding these relationships could lead to methods for obtaining hydraulic information from image-derived metrics of WSR (i.e., surface reflectance). We collected field data on flow depth and velocity using an acoustic Doppler current profiler and simultaneously measured WSR using a custom built ultrasonic distance sensor on a diverse set of rivers ranging from a 15 m wide supraglacial river on the Greenland Ice Sheet to 100 m wide gravel-bed rivers in Wyoming and Oregon. Simultaneous multi- and hyperspectral image data sets indicate that image-derived surface reflectance is strongly correlated with WSR. Temporally distributed point measurements of flow depth, velocity, and WSR on the supraglacial river capture a threefold range in discharge (6 m3/s to 17 m3/s) and indicate that flow velocity is a primary control on WSR in smaller channels, even in the absence of sediment-induced bed roughness. Spatially distributed field measurements from large gravel-bed rivers suggests that spatial variability of WSR in the thalweg corresponds with geomorphic facies while WSR along the channel margins is more significantly influenced by grain size, relative submergence, and bank geometry. These findings suggest that

  18. The removal of pathogens in surface-flow constructed wetlands and its implications for water reuse.

    PubMed

    Ghermandi, A; Bixio, D; Traverso, P; Cersosimo, I; Thoeye, C

    2007-01-01

    Microbiological quality represents the biggest concern to the reuse of treated wastewater. This paper reports and discusses the results of an international survey on the removal of indicators of microbiological contamination in surface-flow constructed wetlands. Constructed wetlands consistently provide a reduction of 90-99% (1-2 log-removal) in the concentration of indicators such as coliform bacteria and faecal streptococci. This removal is found in wetlands treating water from different types of pretreatment (primary sedimentation, activated sludge, trickling filter, maturation ponds). On the other hand, when the influent is of high microbiological quality, wetlands act as sources of pathogenic contamination. The final water quality, however, is still compatible with medium to no-contact recreational activities and other final water uses. High variability in the effluent quality and seasonality might limit the opportunities for reuse. The role of constructed wetlands in different treatment schemes and the remaining open questions concerning removal mechanisms and reference pathogens are discussed.

  19. IMPLICATION OF LAKE WATER RESIDENCE TIME ON THE CLASSIFICATION OF NORWEGIAN SURFACE WATER SITES INTO PROGRESSIVE STAGES OF NITROGEN SATURATION

    EPA Science Inventory

    Seasonal behaviour of NO3- in surface water is often used as an indicator on a catchment's ability to retain N from atmospheric deposition. In this paper, we classify 12 pristine sites (five streams and seven lakes) in southernmost Norway according to the N saturation stage conce...

  20. IMPLICATION OF LAKE WATER RESIDENCE TIME ON THE CLASSIFICATION OF NORWEGIAN SURFACE WATER SITES INTO PROGRESSIVE STAGES OF NITROGEN SATURATION

    EPA Science Inventory

    Seasonal behaviour of NO3- in surface water is often used as an indicator on a catchment's ability to retain N from atmospheric deposition. In this paper, we classify 12 pristine sites (five streams and seven lakes) in southernmost Norway according to the N saturation stage conce...

  1. Small-scale martian polygonal terrain: Implications for liquid surface water

    USGS Publications Warehouse

    Seibert, N.M.; Kargel, J.S.

    2001-01-01

    Images from the Mars Orbiter Camera (MOC) through August 1999 were analyzed for the global distribution of small-scale polygonal terrain not clearly resolved in Viking Orbiter imagery. With very few exceptions, small-scale polygonal terrain occurs at middle to high latitudes of the northern and southern hemisphere in Hesperian-age geologic units. The largest concentration of this terrain occurs in the Utopia basin in close association with scalloped depressions (interpreted as thermokarst) and appears to represent an Amazonia event. The morphology and occurence of small polygonal terrain suggest they are either mud desiccation cracks or ice-wedge polygons. Because the small-scale polygons in Utopia and Argyre Planitiae are associated with other cold-climate permafrost or glacial features, an ice-wedge model is preferred for these areas. Both cracking mechanisms work most effectively in water- or ice-rich finegrained material and may imply the seasonal or episodic existence of liquid water at the surface.

  2. Climatic driven variability of surface water energy potential and implications for future hydroelectricity

    NASA Astrophysics Data System (ADS)

    Worman, A. L. E.; Lindstrom, G.

    2014-12-01

    An average year the production in Norway and Sweden is around 190 TWh and these two countries stand for about 70% of the hydropower energy stored in the available reservoirs of Europe. There are large challenges for the future use of this regulatory capacity with regard to balancing the electricity production in Europe under climate variability, compliance to water management plans under the Water Framework Directive and to the shifts to more renewable, but intermittent, energy sources required by the Renewable Energy Directive. A main aim of this project is to describe the variation over time of hydrological fluxes across Scandinavia in terms of their energy properties and to link that information to climatic factors and the regulation of hydroelectricty. Along these lines we explored daily data of digitalized hydro-climatological data from 1961, which were used to calibrate the HBV-model for 1001 watersheds in Sweden and the energy potential has been estimated as an average for that period (Figure below). These tentative results show that the surface water energy potential constitutes about one per mille of the latent heat flux due to evapotranspiration and it is, therefore, very sensitive to any fluctuation in the energy quantities of the hydrometeorological system. Tentative analysis suggests that the energy availability of surface water in Sweden exhibits significant decadal long fluctuations from 115 TWh/year up to 180 TWh/year, which follow several different time scales and periodicities, ranging from century-long trends to fluctuations occurring on time scales of a decade and shorter. In addition, recent investigations show that land-use changes and hydropower regulation has caused significant changes in the annual runoff periodicity in Swedish rivers during the 20th century. Those changes in the annual periodicities are caused by structural alterations in river basins affected by intense agriculture and hydropower regulation.

  3. Contrasting optical properties of surface waters across the Fram Strait and its potential biological implications

    NASA Astrophysics Data System (ADS)

    Pavlov, Alexey K.; Granskog, Mats A.; Stedmon, Colin A.; Ivanov, Boris V.; Hudson, Stephen R.; Falk-Petersen, Stig

    2015-03-01

    Underwater light regime is controlled by distribution and optical properties of colored dissolved organic matter (CDOM) and particulate matter. The Fram Strait is a region where two contrasting water masses are found. Polar water in the East Greenland Current (EGC) and Atlantic water in the West Spitsbergen Current (WSC) differ with regards to temperature, salinity and optical properties. We present data on absorption properties of CDOM and particles across the Fram Strait (along 79° N), comparing Polar and Atlantic surface waters in September 2009 and 2010. CDOM absorption of Polar water in the EGC was significantly higher (more than 3-fold) compared to Atlantic water in the WSC, with values of absorption coefficient, aCDOM(350), m- 1 of 0.565 ± 0.100 (in 2009) and 0.458 ± 0.117 (in 2010), and 0.138 ± 0.036 (in 2009) and 0.153 ± 0.039 (in 2010), respectively. An opposite pattern was observed for particle absorption with higher absorption found in the eastern part of the Fram Strait. Average values of particle absorption (aP(440), m- 1) were 0.016 ± 0.013 (in 2009) and 0.014 ± 0.011 (in 2010), and 0.047 ± 0.012 (in 2009) and 0.016 ± 0.014 (in 2010), respectively for Polar and Atlantic water. Thus absorption of light in eastern part of the Fram Strait is dominated by particles - predominantly phytoplankton, and the absorption of light in the western part of the strait is dominated by CDOM, with predominantly terrigenous origin. As a result the balance between the importance of CDOM and particulates to the total absorption budget in the upper 0-10 m shifts across Fram Strait. Under water spectral irradiance profiles were generated using ECOLIGHT 5.4.1 and the results indicate that the shift in composition between dissolved and particulate material does not influence substantially the penetration of photosynthetic active radiation (PAR, 400-700 nm), but does result in notable differences in ultraviolet (UV) light penetration, with higher attenuation in the

  4. Nickel Alloy Primary Water Bulk Surface and SCC Corrosion Film Analytical Characterization and SCC Mechanistic Implications

    SciTech Connect

    Morton, D.; Lewis, N.; Hanson, M.; Rice, S.; Sanders, P.

    2007-04-18

    Alloy 600 corrosion coupon tests were performed: (1) to quantify the temperature dependency of general corrosion and (2) to characterize the composition and structure of bulk surface corrosion films for comparison with ongoing primary water SCC (PWSCC) crack tip corrosion film analyses. Results suggest that the thermal activation energy of Alloy 600 corrosion is consistent with the thermal activation energy of nickel alloy PWSCC. Analytical investigations of the structure and composition of Alloy 600 bulk surface corrosion oxides revealed a duplex (inner and outer) oxide layer structure. The outer layer is discontinuous and comprised of relatively large (1 to 3 {micro}m) nickel ferrite crystals and smaller ({approx}0.1 {micro}m) chromium containing nickel ferrite crystals. The inner layer consists of a relatively continuous chromite spinel (major phase) and chromia (Cr{sub 2}O{sub 3} minor phase) which formed through non-selective oxidation. Chromia and dealloyed Alloy 600 (highly Ni enriched metal) were only observed at 337 C (640 F) and only along the boundaries of deformation induced fine grains and subcells. Specimens having deformation free surfaces exhibited continuous uniform inner chromite spinel oxide layers. Specimens with machining induced surface deformation produced non-uniform inner layer oxides (chromite spinel, Cr{sub 2}O{sub 3} and unoxidized material). PWSCC crack tip oxides, in contrast, were fine grain (no duplex structure) and consisted of both chromium rich spinels and ''NiO'' structure oxides. Generally, nickel rich oxides were more abundant under more oxidized conditions (reduced coolant hydrogen) and spinel rich crack tip oxides were favored under more reducing conditions (increased coolant hydrogen). Bulk surface corrosion film thickness did not correlate with observed SCC growth rates. These results suggest that corrosion is not the rate controlling step of PWSCC but rather that PWSCC and corrosion have a common rate controlling sub

  5. Energy Crops and their Implications on Soil Carbon Sequestration, Surface Energy and Water Balance

    NASA Astrophysics Data System (ADS)

    Song, Y.; Barman, R.; Jain, A. K.

    2011-12-01

    The quest to meet growing energy demand with low greenhouse gas emissions has increased attention on the potential of existing and advanced biomass energy crops. Potential energy crops include row crops such as corn, and perennial grasses such as switchgrass. However, a massive expansion of bioenergy crops raises many questions such as: how and where to grow energy crops; and what will be the impacts of growing large scale biofuel crops on the terrestrial hydrological cycle, the surface energy budget, soil carbon sequestration and the concurrent effects on the climate system. An integrated modeling system is being developed with in the framework of a land surface model, the Integrated Science Assessment Model (ISAM), and being applied to address these questions.This framework accounts for the biophysical, physiological and biogeochemical systems governing important processes that regulate crop growth including water, energy and nutrient cycles within the soil-plant-atmosphere system. One row crop (Corn) and two energy crops (Switchgrass and Miscanthus) are studied in current framework. Dynamic phenology processes and parameters for simulating each crop have been developed using observed data from a north to south gradient of field trial sites. This study will specifically focus on the agricultural regions in the US and in Europe. The potential productivity of these three crops will be assessed in terms of carbon sequestration, surface energy and water balance and their spatial variability. This study will help to quantify the importance of various environmental aspects towards modeling bioenergy crops and to better understand the spatial and temporal dynamics of bioenergy crop yields.

  6. An AIMD study of the CPD dimer repair mechanism in water: reaction free energy surface and mechanistic implications

    PubMed Central

    Hassanali, Ali A.; Zhong, Dongping; Singer, Sherwin J.

    2011-01-01

    In a series of two papers we report the detailed mechanism of cyclobutane pyrimidine dimer repair in aqueous solvent using ab initio simulations. Umbrella sampling is used to determine the free energy surface for dimer splitting. The two dimensional free energy surface for splitting of the C5-C5′ and C6-C6′ bonds on the anion surface is reported. The splitting of the C5-C5′ and C6-C6′ bonds occurs on a picosecond timescale. The transition state along the splitting coordinate in the anion state coincides with a maximum in the free energy along the same coordinate on the neutral surface. The implication is that back electron transfer occurring before the anion reaches the transition state leads to re-formation of the cyclobutane dimer, while back electron transfer after transit through the transition state, leads to successful repair. Based on our calculations for CPD splitting in water, we propose a framework for understanding how various factors, such as solvent polarity, can control repair efficiency. This framework explains why back electron transfer leads predominantly to unsuccessful repair in some situations, and successful repair in others. A key observation is that the same free energy surfaces that control dimer splitting also govern how the back electron transfer rate changes during the splitting process. Configurational changes of the dimer along the splitting coordinate are also documented. PMID:21417374

  7. Seasonal cycles in radium and barium within a subterranean estuary: Implications for groundwater derived chemical fluxes to surface waters

    NASA Astrophysics Data System (ADS)

    Gonneea, Meagan Eagle; Mulligan, Ann E.; Charette, Matthew A.

    2013-10-01

    There is increasing evidence that submarine groundwater discharge (SGD) is an important source of water and dissolved materials to the ocean. One of the primary tracers of this process is the quartet of radium isotopes (223Ra, 224Ra, 226Ra and 228Ra), whereby excess activities in surface waters can often be attributed to an input supplied via SGD. This approach requires the radium end member activity to be well constrained, however, natural variability in groundwater radium may span several orders of magnitude. Therefore, this variability is usually the main driver of uncertainties in volumetric SGD estimates. To investigate the physical and biogeochemical controls on groundwater radium activities, we conducted a three-year time series of radium and barium, a chemical analogue for radium, within the subterranean estuary of a coastal aquifer (Waquoit Bay, MA, USA). Gonneea et al. (2013) demonstrated that movement of the salinity interface within the subterranean estuary is driven by changes in the hydraulic gradient between groundwater level and sea level height. For Waquoit Bay, seasonal scale sea level change, not groundwater level, was the main driver in hydraulic gradient fluctuations. Seasonal changes in groundwater chemistry can be attributed to the resulting movement of the salinity transition zone between terrestrial and marine groundwater. Landward movement of the interface results in a large release of radium isotopes (226Ra = 1400 dpm 100 L-1) and barium (3000 nmol kg-1) associated with an increase in groundwater salinity. The magnitude of these releases cannot be explained by in situ production or weathering alone, but is likely due to salinity driven desorption from surface-bound sediment inventory. The timing of these peak concentrations is not always in phase with model-derived estimates of SGD; as a result, the groundwater concentration rather than the water flux is the main driver of Ra and Ba inputs to Waquoit Bay surface waters. The behavior of

  8. Drip-Water Temperatures in Caves: Surface Signals or Cave Processes? - Implications for Speleothem Deposits and Paleoclimate Archives

    NASA Astrophysics Data System (ADS)

    Andersen, M. S.; Cuthbert, M. O.; Rau, G. C.; Baker, A.; Roshan, H.; Rutlidge, H.; Marjo, C.; Markowska, M.; Graham, P. W.; Mariethoz, G.

    2013-12-01

    Caves offer a unique opportunity to enter the subsurface to study vadose zone hydrological processes. Limestone caves, with their speleothem deposits, offer additional advantages as archives of past climate. As such they can serve as observatories for past and present hydrological observations. Correct interpretation of past climates using speleothem deposits requires a systematic understanding of karst physico-chemical processes. With the aim of studying near surface flow and heat transport processes, a series of controlled recharge experiments were carried out above Wellington Caves, located in the temperate semi-arid zone of NSW, Australia. Variable amounts of cooled water were irrigated onto the land surface on four consecutive days in January 2013. The applied recharge rates varied from 40 to 70 mm/d and are comparable to mid-sized recharge events. The temperature of the applied water was varied from 0.3 °C to 24.2 °C using ice. Miniature self-contained temperature loggers (DST micro-T, Star Oddi, Iceland) were deployed to measure the soil temperature and strapped directly on to stalactite features inside the cave located about 2 m below the surface. The stalactites have previously activated regularly by mid-sized precipitation events. Below on the cave floor, drip-loggers (Stalagmate, Driptych, UK) were aligned with the stalactites to capture onset of flow as well as drip rates. Three events of inflow were observed in the initially dry cave. The first irrigation did not produce any inflow since the amount of water applied was not large enough to overcome the soil moisture deficit. Subsequently, each inflow had a higher peak drip rate and duration than the previous event. Surprisingly the stalagmite temperature results showed no discernible effect of the cool water applied to the land surface, despite large changes in the soil temperature caused by the irrigation water. Considering the shallow location of the studied cave this highlights that the temperature

  9. Energy implications of bottled water

    NASA Astrophysics Data System (ADS)

    Gleick, P. H.; Cooley, H. S.

    2009-01-01

    As bottled water use continues to expand around the world, there is growing interest in the environmental, economical, and social implications of that use, including concerns about waste generation, proper use of groundwater, hydrologic effects on local surface and groundwater, economic costs, and more. A key concern is how much energy is required to produce and use bottled water. This paper estimates the energy footprint required for various phases of bottled water production, transportation, and use. We do not develop a single comprehensive life-cycle energy estimate because of differences among water sources, bottling processes, transportation costs, and other factors, but we quantify key energy inputs necessary for site-specific assessments. We also apply these inputs to three site-specific examples of the energy required from production to the point of use: local bottled water produced and used in Los Angeles, water bottled in the South Pacific and shipped by cargo ship to Los Angeles, and water bottled in France and shipped in various ways to Los Angeles. For water transported short distances, the energy requirements of bottled water are dominated by the energy used to produce the plastic bottles. Long-distance transport, however, can lead to energy costs comparable to, or even larger than, those of producing the bottle. All other energy costs—for processing, bottling, sealing, labeling, and refrigeration—are far smaller than those for the production of the bottle and transportation. These data can be used to generate specific estimates for different sources, treatments, and delivery options.

  10. The configuration of water on rough natural surfaces: Implications for understanding air-water interfacial area, film thickness, and imaging resolution

    NASA Astrophysics Data System (ADS)

    Kibbey, Tohren C. G.

    2013-08-01

    Previous studies of air-water interfacial areas in unsaturated porous media have often distinguished between interfacial area corresponding to water held by capillary forces between grains and area corresponding to water associated with solid surfaces. The focus of this work was on developing a better understanding of the nature of interfacial area associated with solid surfaces following drainage of porous media. Stereoscopic scanning electron microscopy was used to determine surface elevation maps for eight different surfaces of varying roughness. An algorithm was developed to calculate the true configuration of an air-water interface in contact with the solid surface as a function of capillary pressure. The algorithm was used to calculate surface-associated water configurations for capillary pressures ranging from 10 to 100 cm water. The results of the work show that, following drainage, the configuration of surface-associated water is dominated by bridging of macroscopic surface roughness features over the range of capillary pressures studied, and nearly all of the surface-associated water is capillary held. As such, the thicknesses of surface-associated water were found to be orders-of-magnitude greater than might be expected at the same capillary pressures based on calculations of adsorbed film thickness. The fact that capillary forces in air-water interfaces dominate surface-associated water configuration means that interface shapes are largely unaffected by microscopic surface roughness, and interfaces are considerably smoother than the underlying solid. As such, calculations suggest that microscopic surface roughness likely has minimal impact on the accuracy of surface-associated air-water interfacial areas determined by limited-resolution imaging methods such as computed microtomography.

  11. Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

    USGS Publications Warehouse

    Nelson, Jonathan M.; Kinzel, Paul J.; McDonald, Richard R.; Schmeeckle, Mark

    2016-01-01

    Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based) techniques for measuring water-surface elevations. In ideal laboratory situations with simple flows, appropriate spatial and temporal averaging results in accurate water-surface elevations and water-surface velocities. In test cases, this accuracy is sufficient to allow direct inversion of the governing equations of motion to produce estimates of depth and discharge. Unlike other optical techniques for determining local depth that rely on transmissivity of the water column (bathymetric lidar, multi/hyperspectral correlation), this method uses only water-surface information, so even deep and/or turbid flows can be investigated. However, significant errors arise in areas of nonhydrostatic spatial accelerations, such as those associated with flow over bedforms or other relatively steep obstacles. Using laboratory measurements for test cases, the cause of these errors is examined and both a simple semi-empirical method and computational results are presented that can potentially reduce bathymetric inversion errors.

  12. Three Decades of Landsat-derived Spring Surface Water Dynamics in an Agricultural Wetland Mosaic; Implications for Migratory Shorebirds

    NASA Astrophysics Data System (ADS)

    Schaffer-Smith, D.; Swenson, J. J.; Barbaree, B. A.; Reiter, M. E.

    2016-12-01

    To balance human demand for limited freshwater with biodiversity and other ecosystem values, it is critical that we develop a more thorough understanding of the spatial and temporal extent of surface water resources. Satellite measurements of surface water dynamics offer promise for understanding wetland habitat availability and quality at broad spatial scales. We used an innovative approach combining random forest models and receiver operating characteristic curve analysis to systematically identify a mid-infrared (1.5-1.7 µm) threshold for classification of water and non-water areas at an important stopover site for shorebirds during spring migration. We analyzed water extent dynamics for a 1983-2015 Landsat time series, using a customized data interpolation to fill missing data gaps in classifications of SLC-off Landsat 7 imagery. Combined with a simple masking procedure, our approach identifies inundation in wetlands and agricultural fields in the Sacramento Valley of California at 30-m resolution with an average of 92% accuracy across the time series, which is comparable to other approaches that require more intensive user input. We found substantial variability in interannual and within-season water extent. Flood-irrigated agriculture provided the greatest potential habitat area for shorebirds; however, herbaceous wetlands on federal state and private lands provided the most reliable habitat. Spring water extent has been most limited during the peak of shorebird migration; on average we detected open water on 26,000 ha ( 3% of the study area) in early April, which is only 18% of the average extent in late May. Furthermore, the water extent on the landscape in late March, leading into peak migration, has significantly declined over time. Our findings provide important information that can be used directly in water and wildlife management under climate change. The unique classification and interpolation methods that we developed for this study could be adapted

  13. Effects of surface texture and measurement geometry on the near infrared water-of-hydration absorption bands. Implications for the Martian regolith water content.

    NASA Astrophysics Data System (ADS)

    Pommerol, A.; Schmitt, B.

    Near-IR reflectance spectroscopy is widely used to detect mineral hydration on Solar System surfaces by the observation of absorption bands at 1.9 and 3 µm. Recent studies established empirical relationships between the strength of the 3 µm band and the water content of the studied minerals (Milliken et al., 2005). These results have especially been applied to the OMEGA dataset to derive global maps of the Martian regolith water content (Jouglet et al., 2006 and Milliken et al., 2006). However, parameters such as surface texture and measurement geometry are known to have a strong effect on reflectance spectra but their influence on the hydration bands is poorly documented. The aim of this work is the determination of the quantitative effects of particle size, mixing between materials with different albedo and measurement geometry on the absorption bands at 1.9 and 3 µm. We used both an experimental and a modeling approach to study these effects. Bidirectional reflectance spectra were measured for series of well characterized samples (smectite, volcanic tuff and coals, pure and mixed) and modeled with optical constants of a smectite (Roush, 2005). Criteria commonly used to estimate the strength of the bands were then calculated on these spectra. We show that particle size has a strong effect on the 1.9 and 3 µm bands strength, especially for the finest particles (less than 200 µm). Mixing between a fine smectite powder and anthracite powders with various particle sizes (modeled by a synthetic neutral material) highlights the strong effect of the materials albedo on the hydration band estimation criteria. Measurement geometry has a significant effect on the bands strength for high phase angles. Furthermore, the relative variations of band strength with measurement geometry appear very dependent on the surface texture. We will present in details the relationships between these physical parameters and various criteria chosen to estimate the hydration bands

  14. Fathoms Below: Propagation of Deep Water-driven Fractures and Implications for Surface Expression and Temporally-varying Activity at Europa

    NASA Astrophysics Data System (ADS)

    Walker, C. C.; Craft, K.; Schmidt, B. E.

    2015-12-01

    The fracture and failure of Europa's icy shell are not only observable scars of variable stress and activity throughout its evolution, they also serve key as mechanisms in the interaction of surface and subsurface material, and thus crucial aspects of the study of crustal overturn and ice shell habitability. Galileo images, our best and only reasonable-resolution views of Europa until the Europa Multiple Flyby Mission arrives in the coming decades, illustrates a single snapshot in time in Europa's history from which we deduce many temporally-based hypotheses. One of those hypotheses, which we investigate here, is that sub-surface water-both in the form of Great Lake-sized perched water pockets in the near-surface and the larger global ocean below-drives the deformation, fracture, and failure of the surface. Using Galileo's snapshot in time, we use a 2D/3D hydraulic fracturing model to investigate the propagation of vertical fractures upward into the ice shell, motion of water within and between fractures, and the subsequent break-up of ice over shallow water, forming the chaos regions and other smaller surface features. We will present results from a cohesive fragmentation model to determine the time over which chaos formation occurs, and use a fracking model to determine the time interval required to allow water to escape from basal fractures in the ice shell. In determining the style, energy, and timescale of these processes, we constrain temporal variability in observable activity and topography at the surface. Finally, we compare these results to similar settings on Earth-Antarctica-where we have much higher resolution imagery and observations to better understand how sub-surface water can affect ice surface morphology, which most certainly have implications for future flyby and surface lander exploration.

  15. Surface-water Interface Induces Conformational Changes Critical for Protein Adsorption: Implications for Monolayer Formation of EAS Hydrophobin

    PubMed Central

    Ley, Kamron; Christofferson, Andrew; Penna, Matthew; Winkler, Dave; Maclaughlin, Shane; Yarovsky, Irene

    2015-01-01

    The class I hydrophobin EAS is part of a family of small, amphiphilic fungal proteins best known for their ability to self-assemble into stable monolayers that modify the hydrophobicity of a surface to facilitate further microbial growth. These proteins have attracted increasing attention for industrial and biomedical applications, with the aim of designing surfaces that have the potential to maintain their clean state by resisting non-specific protein binding. To gain a better understanding of this process, we have employed all-atom molecular dynamics to study initial stages of the spontaneous adsorption of monomeric EAS hydrophobin on fully hydroxylated silica, a commonly used industrial and biomedical substrate. Particular interest has been paid to the Cys3-Cys4 loop, which has been shown to exhibit disruptive behavior in solution, and the Cys7-Cys8 loop, which is believed to be involved in the aggregation of EAS hydrophobin at interfaces. Specific and water mediated interactions with the surface were also analyzed. We have identified two possible binding motifs, one which allows unfolding of the Cys7-Cys8 loop due to the surfactant-like behavior of the Cys3-Cys4 loop, and another which has limited unfolding due to the Cys3-Cys4 loop remaining disordered in solution. We have also identified intermittent interactions with water which mediate the protein adsorption to the surface, as well as longer lasting interactions which control the diffusion of water around the adsorption site. These results have shown that EAS behaves in a similar way at the air-water and surface-water interfaces, and have also highlighted the need for hydrophilic ligand functionalization of the silica surface in order to prevent the adsorption of EAS hydrophobin. PMID:26636091

  16. Surface-water Interface Induces Conformational Changes Critical for Protein Adsorption: Implications for Monolayer Formation of EAS Hydrophobin.

    PubMed

    Ley, Kamron; Christofferson, Andrew; Penna, Matthew; Winkler, Dave; Maclaughlin, Shane; Yarovsky, Irene

    2015-01-01

    The class I hydrophobin EAS is part of a family of small, amphiphilic fungal proteins best known for their ability to self-assemble into stable monolayers that modify the hydrophobicity of a surface to facilitate further microbial growth. These proteins have attracted increasing attention for industrial and biomedical applications, with the aim of designing surfaces that have the potential to maintain their clean state by resisting non-specific protein binding. To gain a better understanding of this process, we have employed all-atom molecular dynamics to study initial stages of the spontaneous adsorption of monomeric EAS hydrophobin on fully hydroxylated silica, a commonly used industrial and biomedical substrate. Particular interest has been paid to the Cys3-Cys4 loop, which has been shown to exhibit disruptive behavior in solution, and the Cys7-Cys8 loop, which is believed to be involved in the aggregation of EAS hydrophobin at interfaces. Specific and water mediated interactions with the surface were also analyzed. We have identified two possible binding motifs, one which allows unfolding of the Cys7-Cys8 loop due to the surfactant-like behavior of the Cys3-Cys4 loop, and another which has limited unfolding due to the Cys3-Cys4 loop remaining disordered in solution. We have also identified intermittent interactions with water which mediate the protein adsorption to the surface, as well as longer lasting interactions which control the diffusion of water around the adsorption site. These results have shown that EAS behaves in a similar way at the air-water and surface-water interfaces, and have also highlighted the need for hydrophilic ligand functionalization of the silica surface in order to prevent the adsorption of EAS hydrophobin.

  17. Surface water hydrology and geomorphic characterization of a playa lake system: Implications for monitoring the effects of climate change

    NASA Astrophysics Data System (ADS)

    Adams, Kenneth D.; Sada, Donald W.

    2014-03-01

    Playa lakes are sensitive recorders of subtle climatic perturbations because these ephemeral water bodies respond to the flux of diffuse and channelized flow from their watersheds as well as from direct precipitation. The Black Rock Playa in northwestern Nevada is one of the largest playas in North America and is noted for its extreme flatness, varying less than one meter across a surface area of 310 km2. Geo-referenced Landsat imagery was used to map surface-area fluctuations of ephemeral lakes on the playa from 1972 to 2013 to provide baseline data on surface water hydrology of this system to compare to future hydrologic conditions caused by climate change. The area measurements were transformed into depth and volumetric estimates using results of detailed topographic global positioning system (GPS) surveys and correlated with available surface hydrological and meteorological monitoring data. Playa lakes reach their maximum size (<350 km2) in spring, fed by melting snows from high mountains on the periphery of the drainage basin, and usually desiccate by early- to mid-summer. The combination of a shallow groundwater table, sediment deposition, and hydro-aeolian planation probably are largely responsible for the flatness of the playa. When lakes do not form for a period of several years, the clay- and silt-rich playa surface transforms from one that is hard and durable into one that is soft and puffy, probably from upward capillary movement of water and resultant evaporation. Subsequent flooding restores the hard and durable surface. The near-global availability of Landsat imagery for the last 41 years should allow the documentation of baseline surface hydrologic characteristics for a large number of widely-distributed playa lake systems that can be used to assess the hydrologic effects of future climate changes.

  18. Surface freezing of water.

    PubMed

    Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

  19. Assessing the toxicity of sodium chloride to the glochidia of freshwater mussels: implications for salinization of surface waters.

    PubMed

    Gillis, Patricia L

    2011-06-01

    Chloride concentrations in surface waters have increased significantly, a rise attributed to road salt use. In Canada, this may be a concern for endangered freshwater mussels, many with ranges limited to southern Ontario, Canada's most road-dense region. The acute toxicity of NaCl was determined for glochidia, the mussel's larval stage. The 24h EC50s of four (including two Canadian endangered) species ranged from 113-1430 mg Cl L⁻¹ (reconstituted water, 100 mg CaCO₃ L⁻¹). To determine how mussels would respond to a chloride pulse, natural river water (hardness 278-322 mg CaCO₃ L⁻¹) was augmented with salt. Lampsilis fasciola glochidia were significantly less sensitive to salt in natural water (EC50s 1265-1559 mg Cl L⁻¹) than in reconstituted water (EC50 285 mg L⁻¹). Chloride data from mussel habitats revealed chloride reaches levels acutely toxic to glochidia (1300 mg L⁻¹). The increased salinization of freshwater could negatively impact freshwater mussels, including numerous species at risk.

  20. Groundwater-surface water interactions, vegetation dependencies and implications for water resources management in the semi-arid Hailiutu River catchment, China - a synthesis

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Wenninger, J.; Yang, Z.; Yin, L.; Huang, J.; Hou, L.; Wang, X.; Zhang, D.; Uhlenbrook, S.

    2013-07-01

    During the last decades, large-scale land use changes took place in the Hailiutu River catchment, a semi-arid area in northwest China. These changes had significant impacts on the water resources in the area. Insights into groundwater and surface water interactions and vegetation-water dependencies help to understand these impacts and formulate sustainable water resources management policies. In this study, groundwater and surface water interactions were identified using the baseflow index at the catchment scale, and hydraulic and water temperature methods as well as event hydrograph separation techniques at the sub-catchment scale. The results show that almost 90% of the river discharge consists of groundwater. Vegetation dependencies on groundwater were analysed from the relationship between the Normalized Difference Vegetation Index (NDVI) and groundwater depth at the catchment scale and along an ecohydrogeological cross-section, and by measuring the sap flow of different plants, soil water contents and groundwater levels at different research sites. The results show that all vegetation types, i.e. trees (willow (Salix matsudana) and poplar (Populus simonii), bushes (salix - Salix psammophila), and agricultural crops (maize - Zea mays)), depend largely on groundwater as the source for transpiration. The comparative analysis indicates that maize crops use the largest amount of water, followed by poplar trees, salix bushes, and willow trees. For sustainable water use with the objective of satisfying the water demand for socio-economical development and to prevent desertification and ecological impacts on streams, more water-use-efficient crops such as sorghum, barley or millet should be promoted to reduce the consumptive water use. Willow trees should be used as wind-breaks in croplands and along roads, and drought-resistant and less water-use intensive plants (for instance native bushes) should be used to vegetate sand dunes.

  1. Suborbital-scale surface and deep water records in the subtropical North Atlantic: implications on thermohaline overturn

    NASA Astrophysics Data System (ADS)

    Billups, Katharina; Rabideaux, Nathan; Stoffel, Jared

    2011-10-01

    We reconstruct millennial-scale variations in sea surface hydrography and deep water flow in the northwestern subtropical Atlantic (Ocean Drilling Program Leg 172 Sites 1056 and 1063) with a focus on Marine Isotope Stage (MIS) 9. Together with published records from this region, the new data also afford a longer-term perspective on millennial-scale changes in meridional overturning circulation spanning two full interglacial intervals (MIS 9 and 11) as well as two full glacial intervals (MIS 10 and 12). Planktic foraminiferal δ 18O values indicate relatively stable conditions during the peak warmth of MIS 9, but three large cold excursions disrupt the otherwise smooth transition toward glacial MIS 8. There is no unique response in the Site 1063 benthic foraminiferal δ 13C values that would suggest a concomitant decrease in the relative flux of NADW during these events. Similarly, there is no persistent correlation between millennial-scale variations in surface and deep water hydrography over the entire MIS 8-13 interval. While millennial-scale variations at the sea surface are most pronounced during glacial intervals (and the transitions toward glacial intervals), millennial-scale variations in the deep water hydrography tend to be largest during the warm periods. This observation supports that rapid changes in thermohaline circulation are sensitive to driving forces other than those directly related to ice sheet size. Time series analysis shows that spectral power in the benthic foraminiferal δ 13C record contains periodicities related to the second (˜10 kyr) and fourth harmonics (˜5 kyr) of precession in this record (˜20 kyr) pointing to the importance of tropical processes.

  2. Sublimation of water ice mixed with silicates and tholins: Evolution of surface texture and reflectance spectra, with implications for comets

    NASA Astrophysics Data System (ADS)

    Poch, Olivier; Pommerol, Antoine; Jost, Bernhard; Carrasco, Nathalie; Szopa, Cyril; Thomas, Nicolas

    2016-03-01

    The surfaces of many objects in the Solar System comprise substantial quantities of water ice sometimes mixed with minerals and/or organic molecules. The sublimation of the ice changes the structural and optical properties of these objects. We present laboratory data on the evolution of the structure and the visible and near-infrared spectral reflectance of icy surface analogues of cometary ices, made of water ice, complex organic matter (tholins) and silicates, as they undergo sublimation under low temperature (<-70 °C) and pressure (10-5 mbar) conditions inside the SCITEAS simulation chamber. As the water ice sublimated, we observed in situ the formation of a porous sublimation lag deposit, or sublimation mantle, at the top of the ice. This mantle is a network of filaments made of the non-volatile particles. Organics or phyllosilicates grains, able to interact via stronger inter-particulate forces than olivine grains, can form a foam-like structure having internal cohesiveness, holding olivine grains together. As this mantle builds-up, the band depths of the sub-surface water ice are attenuated until complete extinction under only few millimeters of mantle. Optically thick sublimation mantles are mainly featureless in the near infrared. The absorption bands of the minerals present in the mantle are weak, or even totally absent if minerals are mixed with organics which largely dominate the VIS-NIR reflectance spectrum. During sublimation, ejections of large fragments of mantle, triggered by the gas flow, expose ice particles to the surface. The contrast of brightness between mantled and ice-exposed areas depends on the wavelength range and the dust/ice ratio considered. We describe how the chemical nature of the non-volatiles, the size of their particles, the way they are mixed with the ice and the dust/ice mass ratio influence the texture, activity and spectro-photometric properties of the sublimation mantles. These data provide useful references for

  3. The role of water in the development of surface roughness and mineralogical variability on playa surface sediments: Implications for aeolian erodibility and dust emission

    NASA Astrophysics Data System (ADS)

    Tollerud, Heather J.

    Playas are significant sources for atmospheric mineral dust, but the evolution of their surface erodibility through time is not well established, leading to difficulties in modeling dust emission. Investigation of the spatial and temporal variability of surfaces within dust source regions has the potential to elucidate the processes that control erodibility and to improve model predictions of dust emission. In this dissertation the variability in time and space of surface mineralogical composition, particle size distribution, and surface roughness is measured in a playa (the Black Rock Desert, NV, USA). Water is found to be critical to the development of playa surfaces. Analysis of samples from the Black Rock playa demonstrates that the playa is mainly composed of quartz (˜30 wt%), clay (˜45 wt%), plagioclase (˜10 wt%), calcite (2-15 wt%), and halite (0-40 wt%). Composition varies between the center of the playa (more frequently inundated) and edge, with smaller particles, more clay, less plagioclase, and less calcite in the central areas. The surface roughness of the Black Rock playa is observed through time (2004-2010) using synthetic aperture radar (SAR) remote sensing data. Surface roughness is relatively constant during the dry summer months, but changes significantly from year to year, suggesting that water and inundation have more control on playa surfaces than anthropogenic activity or saltation abrasion. Roughness is low in years with heavy precipitation, but late drying areas of the playa are rough. Small scale lab experiments on a playa analog surface demonstrate that cycles of wetting/drying increase roughness, particularly for surfaces with added CaCO 3; a surface with added CaCO3 produced aggregates of a size appropriate for saltation (<100 microm) through wetting/drying cycles, while a surface with added NaCl remained relatively smooth. These observations suggest a conceptual framework for the development of surfaces in a playa: inundation smooths

  4. The survival of large organic molecules during hypervelocity impacts with water ice: implications for sampling the icy surfaces of moons

    NASA Astrophysics Data System (ADS)

    Hurst, A.; Bowden, S. A.; Parnell, J.; Burchell, M. J.; Ball, A. J.

    2007-12-01

    There are a number of measurements relevant to planetary geology that can only be adequately performed by physically contacting a sample. This necessitates landing on the surface of a moon or planetary body or returning samples to earth. The need to physically contact a sample is particularly important in the case of measurements that could detect medium to low concentrations of large organic molecules present in surface materials. Large organic molecules, although a trace component of many meteoritic materials and rocks on the surface of earth, carry crucial information concerning the processing of meteoritic material in the surface and subsurface environments, and can be crucial indicators for the presence of life. Unfortunately landing on the surface of a small planetary body or moon is complicated, particularly if surface topography is only poorly characterised and the atmosphere thin thus requiring a propulsion system for a soft landing. One alternative to a surface landing may be to use an impactor launched from an orbiting spacecraft to launch material from the planets surface and shallow sub-surface into orbit. Ejected material could then be collected by a follow-up spacecraft and analyzed. The mission scenario considered in the Europa-Ice Clipper mission proposal included both sample return and the analysis of captured particles. Employing such a sampling procedure to analyse large organic molecules is only viable if large organic molecules present in ices survive hypervelocity impacts (HVIs). To investigate the survival of large organic molecules in HVIs with icy bodies a two stage light air gas gun was used to fire steel projectiles (1-1.5 mm diameter) at samples of water ice containing large organic molecules (amino acids, anthracene and beta-carotene a biological pigment) at velocities > 4.8 km/s.UV-VIS spectroscopy of ejected material detected beta-carotene indicating large organic molecules can survive hypervelocity impacts. These preliminary results

  5. Centennial-scale surface water δ18O anomalies in the Florida Straits: Implications of magnitude and timing (Invited)

    NASA Astrophysics Data System (ADS)

    Lund, D. C.

    2009-12-01

    Foraminiferal δ18O and Mg/Ca data from the Straits of Florida imply that surface water δ18O (δ18Ow) increased by ~0.4 ‰ during the Little Ice Age (LIA: ~1200 to 1850 A.D.) (Lund et al., 2006), coincident with drier conditions in the vicinity of the Cariaco Basin (Haug et al., 2001). Together, these lines of evidence suggest the mean position of the Atlantic Inter-Tropical Convergence Zone (ITCZ) migrated southward during the LIA. However, large changes in δ18Ow are difficult to reconcile with the modern spatial relationship of δ18Ow vs. salinity for surface waters of the low latitude Atlantic. We consider two possibilities: 1) Florida Straits δ18Ow instead responded to changes in thermocline δ18Ow, or 2) an erroneous Mg/Ca calibration yielded artificially large δ18Ow anomalies. We find that recent multi-variate calibrations (deMenocal et al., 2007) produce more reasonable changes in δ18Ow (<0.1 ‰) during the last millennium. The results also suggest Florida Current SSTs cooled by ~0.5°C during the LIA and salinity increased by 0.2-0.3 psu. Thus, the overall picture of saltier surface waters in the Florida Straits and southward ITCZ migration during the LIA appears to be robust, despite a possible bias in our initial δ18Ow estimates. The Florida Current δ18Ow and salinity time series display a strong similarity to atmospheric radiocarbon during the last millennium. Low-resolution age models suggest δ18Ow lags atmospheric Δ14C by 50-100 years, assuming a surface water reservoir age of 400 years. A similar offset is observed between the δ18Ow records and an estimate of radiocarbon production rate. If the reservoir age remained constant through time, then it seems likely that solar variability paced migration of the ITCZ during the last millennium. If, on the other hand, the reservoir age was 300 years or less, then changes in ITCZ position may have led atmospheric Δ14C. Such a relationship would imply that exchange of carbon between the ocean and

  6. Surface-water surveillance

    SciTech Connect

    Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

  7. Water surface is acidic

    PubMed Central

    Buch, Victoria; Milet, Anne; Vácha, Robert; Jungwirth, Pavel; Devlin, J. Paul

    2007-01-01

    Water autoionization reaction 2H2O → H3O− + OH− is a textbook process of basic importance, resulting in pH = 7 for pure water. However, pH of pure water surface is shown to be significantly lower, the reduction being caused by proton stabilization at the surface. The evidence presented here includes ab initio and classical molecular dynamics simulations of water slabs with solvated H3O+ and OH− ions, density functional studies of (H2O)48H+ clusters, and spectroscopic isotopic-exchange data for D2O substitutional impurities at the surface and in the interior of ice nanocrystals. Because H3O+ does, but OH− does not, display preference for surface sites, the H2O surface is predicted to be acidic with pH < 4.8. For similar reasons, the strength of some weak acids, such as carbonic acid, is expected to increase at the surface. Enhanced surface acidity can have a significant impact on aqueous surface chemistry, e.g., in the atmosphere. PMID:17452650

  8. Surface Water in Hawaii

    USGS Publications Warehouse

    Oki, Delwyn S.

    2003-01-01

    Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

  9. Distributions of the C37:4 alkenone in the water column, surface sediments and sediment cores of the northern high latitude oceans: implications for palaeoceanography

    NASA Astrophysics Data System (ADS)

    Bendle, J. A.; Rosell-Melé, A.; Ziveri, P.

    2003-04-01

    glacial. Global and Planetary Change. SICRE, M.-A., BARD, E., EZAT, U. &ROSTEK, F. (2002) Alkenone distributions in the North Atlantic and Nordic sea surface waters. Geochemistry Geophysics Geosystems, 3(2), 10.1029/2001GC000159. SIKES, E. &SICRE, M.-A. (2001) The relationship of the tetra-unsaturated C37 alkenone to salinity and temperature: implications for paleo studies. Geochemistry Geophysics Geosystems, Submitted.

  10. High Precision Boron Isotopic Analysis in Coral Skeletons: Implications for pCO2 variation in surface water

    NASA Astrophysics Data System (ADS)

    Wang, B.; You, C.; Huang, K.; Chung, C.; Wan, N.; Chiu, C.

    2006-12-01

    To advance our knowledge of oceanic CO2 variation in northwestern Pacific, a boron isotopic record with monthly resolution in a hermatypic coral was investigated using high precision Cs2BO2+ thermal ionization mass spectrometry (TIMS) technique. Trace elements (B and Sr) and stable isotopes (O and C) were also analyzed to constrain sea surface temperature and symbiotic photosynthesis. After filtering out short-term climatic influence, coralline δ^{11}B vary seasonally with a range between 23.1 and 29.1 ‰ during 1988 to 1991. The coralline δ13C reflect also seasonal variability and show high photosynthetic activity in summer-fall months. The δ18O in skeleton was affected by temperature and kinetic fractionation. The pH reconstruction based on δ^{11}B range between 7.6 and 8.3, implying pH of calcification microenvironment were faithful recorded. High pH values appear in the summer-fall intervals, agree with active photosynthesis and high ambient temperature. However, intensity variation of Kuroshio Current water masses at the Philippine Sea and the South China Sea, as well as local upwelling, El Niño/La Niña episodes, may also need to be considered. An interesting relationship between δ^{11}B and the CO2 fugacity was obtained for summer-fall and winter-spring, respectively. It is also important to note that extra care should be taken when applying δ^{11}B as a proxy for pH reconstruction in SST sensitive regions.

  11. Probing Effect of Salinity and pH on Surface Interactions between Air Bubbles and Hydrophobic Solids: Implications on Colloidal Assembly at Air/Water Interface.

    PubMed

    Cui, Xin; Shi, Chen; Zhang, Shuo; Xie, Lei; Liu, Jing; Jiang, Dazhi; Zeng, Hongbo

    2017-04-05

    In this work, bubble probe atomic force microscope (AFM) was employed to quantify the interactions between two air bubbles and between an air bubble and an octadecyltrichlorosilane (OTS)-hydrophobized mica under various aqueous conditions. The key parameters (e.g. surface potentials, decay length of hydrophobic attraction) were obtained by analyzing the measured forces through a theoretical model based on Reynolds lubrication theory and augmented Young-Laplace equation by including effect of disjoining pressure. The bubble-OTS hydrophobic attraction with a decay length of 1.0 nm was found to be independent of solution pH and salinity. These parameters were further used to predict the attachment of OTS-hydrophobized particles onto air/water interface, demonstrating that particle attachment driven by hydrophobic attraction could be facilitated by suppressing electrical double-layer repulsion at low pH or high salinity condition. This facile methodology can be readily extended to quantify interactions of many other colloidal particles with gas/water and oil/water interfaces, with implications on colloidal assembly at different interfaces in many engineering applications.

  12. Cryptosporidiosis and surface water.

    PubMed Central

    Gallaher, M M; Herndon, J L; Nims, L J; Sterling, C R; Grabowski, D J; Hull, H F

    1989-01-01

    In the period July through October, 1986, 78 laboratory-confirmed cases of cryptosporidiosis were identified in New Mexico. To determine possible risk factors for development of this disease, we conducted a case-control study; 24 case-patients and 46 neighborhood controls were interviewed. Seventeen (71 per cent) of the 24 case-patients were females, seven (29%) were males; their ages ranged from 4 months to 44 years, median 3 years. There was a strong association between drinking surface water and illness: five of the 24 case-patients, but none of the 46 controls drank untreated surface water. Among children, illness was also associated with attending a day care center where other children were ill (odds ratio = 13.1). PMID:2909180

  13. Groundwater—Surface waters interactions at slope and catchment scales: implications for landsliding in clay-rich slopes

    NASA Astrophysics Data System (ADS)

    Marc, Vincent; Bertrand, Catherine; Malet, Jean-Philippe; Carry, Nicolas; Simler, Roland; Cervi, Federico

    2017-04-01

    Understanding water infiltration and transfer in soft-clay shales slopes is an important scientific issue, especially for landsliding. Geochemical investigations are carried out at the Super-Sauze and Draix-Laval landslides, both developed in the Callovo-Oxfordian black marls, with the objective to define the origin of the groundwater. In situ investigations, soil leaching experiments and geochemical modeling are combined to identify the boundaries of the hydrological systems. At Super-Sauze, the observations indicate that an external water flow occurs in the upper part of the landslide at the contact between the weathered black marls and the overlying formations, or at the landslide basement through a fault network. Such external origin of water is not observed at the local scale of the Draix-Laval landslide but is detected at the catchment scale with the influence of deep waters in the streamwater quality of low river flows. Hydrogeological conceptual models are proposed emphasizing the role of the interactions between local (slope) and regional (catchment) flow systems. The observations suggest that this situation is a common case in the Alpine area. Expected consequences of the regional flows on slope stability are discussed in term of rise of pore water pressures and physicochemical weathering of the clay shales.

  14. Managing forage-based cow-calf operations in subtropics: Implication to surface and ground water quality

    USDA-ARS?s Scientific Manuscript database

    water quality “impairment” around the world. In most cases, eutrophication has accelerated by increased inputs of phosphorus and/or nitrogen due to intensification of crop and animal production systems since the early 1990’s. As animal-based agriculture has evolved to larger production in subtropica...

  15. A mixing analysis of surface water in the Oyashio region: Its implications and application to variations of the spring bloom

    NASA Astrophysics Data System (ADS)

    Kono, Tokihiro; Sato, Masatoshi

    2010-09-01

    We analyzed the near-daily hydrographic data collected from ships at a station southeast of Hokkaido Japan during April 2007. We calculated mixing ratios of Coastal Oyashio Water (COW), Oyashio Water (OYW), and modified Kuroshio Water (MKW). The COW mixing ratio tended to be high in depths shallower than 30 m during April, while the OYW ratio was high at the deeper depths. Diapycnal mixing due to the strong wind was suggested between these layers. It is suggested that stratification of low-salinity COW initiates the spring bloom in early-April, but that it is not important for temporal changes of chlorophyll at each depth during and after the bloom. Despite the intense water exchange at the station, the COW ratio correlated significantly with chlorophyll for the overall data set during April and for the data in 2-4-day blocks. Silicic acid, nitrate, and phosphate were also significantly correlated with the COW ratio for each 2-4-day block. This implies that each of these variables changed simultaneously at a constant COW ratio within the temporal and spatial scales of the phytoplankton bloom, were it not for the occurrence of vigorous vertical mixing and large-scale advective events. Using the linear regression equations for each 2-4-day block, we calculated time-series of chlorophyll and nutrients at the mean COW ratio (46%). Their rates of change in these series reveal the spring bloom dynamics in 2007 as follows: The spring bloom ended due to silicate depletion and grazing by large zooplankton in mid-April. In late-April, the nutrients increased, but chlorophyll decreased, indicating little nutrient utilization.

  16. Simulated climate change impact on summer dissolved organic carbon release from peat and surface vegetation: implications for drinking water treatment.

    PubMed

    Ritson, Jonathan P; Bell, Michael; Graham, Nigel J D; Templeton, Michael R; Brazier, Richard E; Verhoef, Anne; Freeman, Chris; Clark, Joanna M

    2014-12-15

    Uncertainty regarding changes in dissolved organic carbon (DOC) quantity and quality has created interest in managing peatlands for their ecosystem services such as drinking water provision. The evidence base for such interventions is, however, sometimes contradictory. We performed a laboratory climate manipulation using a factorial design on two dominant peatland vegetation types (Calluna vulgaris and Sphagnum Spp.) and a peat soil collected from a drinking water catchment in Exmoor National Park, UK. Temperature and rainfall were set to represent baseline and future conditions under the UKCP09 2080s high emissions scenario for July and August. DOC leachate then underwent standard water treatment of coagulation/flocculation before chlorination. C. vulgaris leached more DOC than Sphagnum Spp. (7.17 versus 3.00 mg g(-1)) with higher specific ultraviolet (SUVA) values and a greater sensitivity to climate, leaching more DOC under simulated future conditions. The peat soil leached less DOC (0.37 mg g(-1)) than the vegetation and was less sensitive to climate. Differences in coagulation removal efficiency between the DOC sources appears to be driven by relative solubilisation of protein-like DOC, observed through the fluorescence peak C/T. Post-coagulation only differences between vegetation types were detected for the regulated disinfection by-products (DBPs), suggesting climate change influence at this scale can be removed via coagulation. Our results suggest current biodiversity restoration programmes to encourage Sphagnum Spp. will result in lower DOC concentrations and SUVA values, particularly with warmer and drier summers.

  17. Water-quality assessment of south-central Texas: Occurrence and distribution of volatile organic compounds in surface water and ground water, 1983-94, and implications for future monitoring

    USGS Publications Warehouse

    Ging, P.B.; Judd, L.J.; Wynn, K.H.

    1997-01-01

    The study area of the South-Central Texas study unit of the National Water-Quality Assessment Program comprises the Edwards aquifer in the San Antonio region and its catchment area. The first phase of the assessment includes evaluation of existing water-quality data for surface water and ground water, including volatile organic compounds, to determine the scope of planned monitoring. Most analyses of volatile organic compounds in surface water are from the National Pollutant Discharge Elimination System sites in San Antonio, Texas. Nine volatile organic compounds were detected at the six sites. The three compounds with the most detections at National Pollutant Discharge Elimination System sites are 1,2,4-trimethylbenzene, toluene, and xylene. Analysis of volatile organic compounds in ground water was limited to Edwards aquifer wells. Twenty-eight volatile organic compounds were detected in samples from 89 wells. The five most commonly detected compounds in samples from wells, in descending order, are tetrachloroethene, trichloroethene, bromoform, chloroform, and dibromochloromethane. Detections of volatile organic compounds in surface water and ground water within the South-Central Texas study area are limited to site-specific sources associated with development; therefore, planned monitoring for possible detections of volatile organic compounds as part of the National Water-Quality Assessment Program will emphasize areas of expanding population and development. Monitoring of volatile organic compounds is planned at National Pollutant Discharge Elimination System sites, at basic fixed surface-water sites, and in the ground-water study-unit surveys.

  18. Internal Surface Water Flows

    USGS Publications Warehouse

    Murray, Mitchell H.

    1999-01-01

    Introduction The South Florida Ecosystem Restoration Program is an intergovernmental effort to reestablish and maintain the ecosystem of south Florida. One element of the restoration effort is the development of a firm scientific basis for resource decision making.The U.S. Geological Survey (USGS) provides scientitic information as part of the South Florida Ecosystem Restoration Program. The USGS began its own project, called the South Florida Ecosystem Project in fiscal year 1995 for the purpose of gathering hydrologic, cartographic, and geologic data that relate to the mainland of south Florida, Florida Bay, and the Florida Keys and Reef ecosystems. Historical changes in water-management practices to accommodate a large and rapidly growing urban population along the Atlantic coast, as well as intensive agricultural activities, have resulted in a highly managed hydrologic system with canals, levees, and pumping stations. These structures have altered the hydology of the Everglades ecosystem on both coastal and interior lands. Surface-water flows in a direction south of Lake Okeechobee have been regulated by an extensive canal network, begun in the 1940's, to provide for drainage, flood control, saltwater intrusion control, agricultural requirements, and various environmental needs. Much of the development and subsequent monitoring of canal and river discharge south of Lake Okeechobee has traditionally emphasized the eastern coastal areas of Florida. Recently, more emphasis has been placed on providing a more accurate water budget for internal canal flows.

  19. Near Surface Water on Europa?

    NASA Astrophysics Data System (ADS)

    Schmidt, B. E.; Gooch, B. T.; Patterson, G.; Blankenship, D. D.

    2016-12-01

    Europa's chaos terrains are generally agreed upon to have formed through disruption of the ice shell and interaction with water, but the exact details are debated. Thrace Macula, one of the largest chaos features, was initially considered to be an extrusive flow due its dark coloration and raised topography. Upon closer inspection, the volcanic interpretation was dismissed, in favor of suggestions that motion of brines through the ice, akin to brine drainage in sea ice, would explain the dark coloration. However no model has clearly explained how both the color and topography of the feature are produced, nor the large ice rafts at its center. In this presentation, we will show that disruption of the surface ice after emplacement of a subsurface water lense can reproduce all of the observations of Thrace Macula if the ice in the upper few kilometers is highly fractured or porous. We will demonstrate with simple hydrologic models that hydraulic gradients within the surrounding ice are sufficient to produce a shallow brine zone that migrates through the ice and creates a distributed network of brine-soaked and refrozen ice. These results suggest that liquid water was still present at Thrace Macula at the time of Galileo, and that future observations of this region may reveal significant changes. Such observations have important implications for crustal recycling, material transport and the long-term habitability of Europa's subsurface and ocean.

  20. Spatial variations in archaeal lipids of surface water and core-top sediments in the South china sea and their implications for paleoclimate studies.

    PubMed

    Wei, Yuli; Wang, Jinxiang; Liu, Jie; Dong, Liang; Li, Li; Wang, Hui; Wang, Peng; Zhao, Meixun; Zhang, Chuanlun L

    2011-11-01

    The South China Sea (SCS) is the largest marginal sea of the western Pacific Ocean, yet little is known about archaeal distributions and TEX₈₆-based temperatures in this unique oceanic setting. Here we report findings of abundances in both core lipids (CL) and intact polar lipids (IPL) of Archaea from surface water (CL only) and core-top sediments from different regions of the SCS. TEX₈₆-derived temperatures were also calculated for these samples. The surface water had extremely low abundances of CL (average of 0.05 ± 0.13 ng/liter; n = 75), with higher values present in regions where upwelling is known to occur. The core-top sediments had CL values of 0.1 to 0.9 μg/g, which are on the low end of CL concentrations reported for other marine sediments and may reflect the oligotrophic nature of the open SCS. The IPL of Archaea accounted for 6 to 36.4% of total lipids (CL plus IPL), indicating that the majority of archaeal lipids in core-top sediments were derived from nonliving cells. The TEX₈₆-based temperatures of surface water were overall lower than satellite-based sea surface temperatures or CTD-measured in situ temperatures. The core-top sediment samples, however, had TEX₈₆ temperatures very close to the mean annual sea surface temperatures, except for samples with water depths of less than 100 m. Our results demonstrated low and heterogeneous distributions of archaeal lipids in surface water and core-top sediments of the SCS, which may reflect local or regional differences in productivity of Archaea. While TEX₈₆-based temperatures for core-top marine sediments at deep water depths (>100 m) generally reflected mean annual sea surface temperatures, TEX₈₆ temperatures in surface water varied basin wide and underestimated sea surface temperatures in most locations for the season when surface water samples were collected.

  1. Spatial Variations in Archaeal Lipids of Surface Water and Core-Top Sediments in the South China Sea and Their Implications for Paleoclimate Studies▿†

    PubMed Central

    Wei, Yuli; Wang, Jinxiang; Liu, Jie; Dong, Liang; Li, Li; Wang, Hui; Wang, Peng; Zhao, Meixun; Zhang, Chuanlun L.

    2011-01-01

    The South China Sea (SCS) is the largest marginal sea of the western Pacific Ocean, yet little is known about archaeal distributions and TEX86-based temperatures in this unique oceanic setting. Here we report findings of abundances in both core lipids (CL) and intact polar lipids (IPL) of Archaea from surface water (CL only) and core-top sediments from different regions of the SCS. TEX86-derived temperatures were also calculated for these samples. The surface water had extremely low abundances of CL (average of 0.05 ± 0.13 ng/liter; n = 75), with higher values present in regions where upwelling is known to occur. The core-top sediments had CL values of 0.1 to 0.9 μg/g, which are on the low end of CL concentrations reported for other marine sediments and may reflect the oligotrophic nature of the open SCS. The IPL of Archaea accounted for 6 to 36.4% of total lipids (CL plus IPL), indicating that the majority of archaeal lipids in core-top sediments were derived from nonliving cells. The TEX86-based temperatures of surface water were overall lower than satellite-based sea surface temperatures or CTD-measured in situ temperatures. The core-top sediment samples, however, had TEX86 temperatures very close to the mean annual sea surface temperatures, except for samples with water depths of less than 100 m. Our results demonstrated low and heterogeneous distributions of archaeal lipids in surface water and core-top sediments of the SCS, which may reflect local or regional differences in productivity of Archaea. While TEX86-based temperatures for core-top marine sediments at deep water depths (>100 m) generally reflected mean annual sea surface temperatures, TEX86 temperatures in surface water varied basin wide and underestimated sea surface temperatures in most locations for the season when surface water samples were collected. PMID:21890672

  2. Sustaining dry surfaces under water

    PubMed Central

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

  3. Sustaining dry surfaces under water.

    PubMed

    Jones, Paul R; Hao, Xiuqing; Cruz-Chu, Eduardo R; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M; Varanasi, Kripa K; Megaridis, Constantine M; Walther, Jens H; Koumoutsakos, Petros; Espinosa, Horacio D; Patankar, Neelesh A

    2015-08-18

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.

  4. Sustaining dry surfaces under water

    NASA Astrophysics Data System (ADS)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-08-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.

  5. Water on a Hydrophobic surface

    NASA Astrophysics Data System (ADS)

    Scruggs, Ryan; Zhu, Mengjue; Poynor, Adele

    2012-02-01

    Hydrophobicity, meaning literally fear of water, is exhibited on the surfaces of non-stick cooking pans and water resistant clothing, on the leaves of the lotus plan, or even during the protein folding process in our bodies. Hydrophobicity is directly measured by determining a contact angle between water and an objects surface. Associated with a hydrophobic surface is the depletion layer, a low density region approximately 0.2 nm thick. We study this region by comparing data found in lab using surface plasmon resonance techniques to theoretical calculations. Experiments use gold slides coated in ODT and Mercapto solutions to model both hydrophobic and hydrophilic surfaces respectively.

  6. Water surface depth instrument

    NASA Technical Reports Server (NTRS)

    Davis, Q. C., IV

    1970-01-01

    Measurement gage provides instant visual indication of water depth based on capillary action and light diffraction in a group of solid, highly polished polymethyl methacrylate rods. Rod lengths are adjustable to measure various water depths in any desired increments.

  7. Dissolved Iron in the Australian Sector of the Southern Ocean During Spring: Implications for the Seasonal Cycle of Iron in Antarctic Surface Waters

    NASA Astrophysics Data System (ADS)

    Sedwick, P. N.; Bowie, A. R.; Ussher, S. J.; Mackey, D. J.; Trull, T. W.; Worsfold, P. J.

    2002-12-01

    Colorimetric flow injection analysis was used to measure dissolved iron (<0.4 μm, dFe) in upper-ocean (<400 m depth) water samples collected from the CLIVAR SR3 section (~142°E) between Tasmania and Antarctica in November-December 2001. These are the first such data for this region during austral spring, and include results from two stations occupied in melting pack ice, as well as one station near the 61°S SOIREE site, occupied twice. Combining these new results with data from a March 1998 cruise and the February 1999 SOIREE campaign allows us to infer seasonal (spring-fall) changes in dFe concentrations in surface waters of our study region, assuming interannual variability is small. The data suggest a seasonal drawdown of ~0.1-0.2 nM dFe in the Subantarctic Zone waters (~47°S); a seasonal accumulation of ~0.1 nM dFe in near-surface (~25 m) waters and a drawdown of ~0.05 nM dFe in deeper (~50-300 m) waters of the Subantarctic Front (~51°S); and little or no seasonal dFe drawdown (~0.05 nM or less) in surface waters south of the Subantarctic Front, where dFe concentrations were uniformly low (~0.1 nM). Thus, if winter mixing provides a significant vertical resupply of dFe to Antarctic surface waters, our results suggest that most of this winter reserve of dissolved iron is removed from the upper water column very early in the growing season. In addition, our new data provide no evidence of significant iron inputs to surface waters from melting sea ice, which may explain the lack of ice-edge algal blooms in this sector of the Southern Ocean, as inferred from ocean-color satellite images.

  8. Surface Water Response Modeling

    EPA Science Inventory

    During response to spills, or for facility planning, the vulnerability of downstream water resources is a major concern. How long and at what concentration do spilled contaminants reach downstream receptors? Models have the potential to answer these questions, but only if they ...

  9. Surface Water Response Modeling

    EPA Science Inventory

    During response to spills, or for facility planning, the vulnerability of downstream water resources is a major concern. How long and at what concentration do spilled contaminants reach downstream receptors? Models have the potential to answer these questions, but only if they ...

  10. Probing Molecular Interactions of Asphaltenes in Heptol Using a Surface Forces Apparatus: Implications on Stability of Water-in-Oil Emulsions.

    PubMed

    Zhang, Ling; Shi, Chen; Lu, Qingye; Liu, Qingxia; Zeng, Hongbo

    2016-05-17

    The behaviors and molecular interactions of asphaltenes are related to many challenging issues in oil production. In this study, the molecular interaction mechanism of asphaltenes in Heptol solvents of varying toluene/n-heptane ratio were directly measured using a surface forces apparatus (SFA). The results showed that the interactions between asphaltene surfaces gradually changed from pure repulsion to weak adhesion as the weight ratio of toluene (ω) in Heptol decreased from ω = 1 to 0. The measured repulsion was mainly due to the steric interactions between swelling asphaltene molecules and/aggregates. The micropipet technique was applied to test the stability of two water-in-oil emulsion droplets attached to glass pipettes. A computer-controlled 4-roll mill fluidic device was also built in-house to investigate the interaction of free-suspending water-in-oil emulsions under dynamic flow conditions. Both micropipet and 4-roll mill fluidic tests demonstrate that asphaltenes adsorbed at oil/water interfaces play a critical role in stabilizing the emulsion drops, in agreement with the repulsion measured between asphaltene surfaces in toluene using SFA, and that interfacial sliding or shearing is generally required to destabilize the protective interfacial apshaltene layers which facilitates the coalescence of emulsion drops. Our results provide insights into the fundamental understanding of molecular interaction mechanisms of asphaltenes in organic solvents and stabilization/destabilization behaviors of water-in-oil emulsions with asphaltenes.

  11. Water in Biomaterials Surface Science

    NASA Astrophysics Data System (ADS)

    Morra, M.

    2001-10-01

    Presents the latest ideas and research on molecular hydration and hydration forces, and how they determine the interaction between water molecules and biomaterials surfaces. Consisting of three sections; theoretical aspects, analytical aspects and practical applications, it begins by placing the properties of water in a proper molecular perspective. The analytical aspects and practical applications offer a complete overview with new insights into the biomaterials/water interface by: - Discussing the latest approaches to the characterisation of water at interfaces and surface modification of biomaterials - Examining the problems related to the understanding and characterisation of interfacial water - Providing new perspectives of the interfacial interactions between materials and the physiological aqueous environment An invaluable resource for researchers in biomaterials surface science and the biotechnology industry.

  12. Evolution of Surface Water Conditions in the Gulf of California During the Past 2000 years: Implications for the North American Monsoon

    NASA Astrophysics Data System (ADS)

    Barron, J. A.; Bukry, D.; Addison, J. A.; McGann, M.; Schwartz, V.; McGeehin, J. P.; McClymont, E.

    2015-12-01

    High-resolution analyses of diatoms, silicoflagellates, biogenic silica, and alkenones in laminated sediment cores from the Guaymas Basin (central Gulf of California) reveal pronounced changes in surface water conditions over the past 2000 years. Prior to ~AD 1200, surface waters in the western Guaymas Basin (boxcore MD02-2517c2 at 27.4850° N, 112.0743°W, water depth 887 m) were characterized by high biologic productivity with alternating assemblages of productive diatoms (Thalassionema nitzschioides, Fragilariopsis doliolus) and silicoflagellates (Octactis pulchra, Dictyocha stapedia). Beginning at ~ AD 1200 productivity declined abruptly in two steps (at ~AD 1200 and ~1500) that were marked by increases in the relative abundance of tropical diatoms and silicoflagellates. In contrast, eastern Guaymas Basin Kasten Core BAM80 E-17 (27.920° N, 111.610°W, 620 m of water depth), was dominated by high biosiliceous productivity during the past 2000 years with increases corresponding to solar minima, arguing that an intensification of winter northwest winds drove coastal upwelling. In both Guaymas Basin records silicoflagellate assemblages suggest surface-water cooling during Medieval Climate Anomaly (MCA; ~AD 800-1200) relative to the intervals before and after. Together, these records support a cooler La Niña-like MCA followed by a warmer El Niño-like Little Ice Age, similar to results obtained from the Santa Barbara Basin to the north. During La Niñas, the Intertropical Convergence Zone (ITCZ) occupies a more northerly position in the eastern tropical Pacific, facilitating summertime surges of Pacific tropical moisture up the Gulf and higher monsoonal precipitation in the southwestern US. A modeling study by Song Feng et al. (2008, JGR) of the broader MCA (AD 800-1300) utilizes La Niña-like Pacific sea surface temperatures to argues for an intensified North American Monsoon during the MCA. Limited terrestrial proxy records from Arizona and New Mexico are

  13. Surface Water Conditions in the Central Gulf of California During the Past 52 Kyrs Based on Diatoms and Silicoflagellates: Implications for Monsoonal Moisture Transport

    NASA Astrophysics Data System (ADS)

    Barron, J. A.; Bukry, D.; Cheshire, H.

    2012-12-01

    Between late fall and early spring persistent northwest winds in the Gulf of California (GoC) cause upwelling of subsurface waters rich in nutrients, resulting in high surface water productivity and the deposition of biogenic silica-rich sediments. Slackening of these winds during the spring leads to progressive northward advection of warmer, more oligotrophic waters. Surges of monsoonal moisture up the axis of the Gulf into the southwestern US begin in July when SSTs in the northern GoC exceed 26°C. Our studies of biogenic SST proxies (diatoms, silicoflagellates, calcium carbonate) reveal that surface waters of the central GoC were too cool between ~10.5 and 7.5 ka (early Holocene) to support northward surges of monsoonal moisture. During this interval, warmer SSTs off the Pacific coast of Baja California appear to have facilitated a more zonal flow of tropical moisture into a geographically broader region of the southwestern US (Barron et al., 2012). High-resolution studies of diatoms and silicoflagellates of the past 52 kyr on well dated cores (MD02-2517/2515) from the central GoC reveal profound changes in GoC surface waters that should have affected the pathways of monsoonal moisture. During Marine Isotope Stage 2 (MIS2), the persistent presence of Distephanus speculum (silicoflagellate) is evidence that the California Current penetrated into the GoC, likely reflecting a southward-shifted Subtropical High pressure cell. Diatoms also suggest an increased presence of cool, low salinity surface waters in the central GoC between ~27 and 18 ka that would not have been conducive to northward surges of monsoonal moisture. The dominance of the diatom Azpeitia nodulifera between 52 and 27 ka is evidence that tropical oligotrophic waters were present year round during MIS3. Silicoflagellates, however, indicate that oligotrophic conditions alternated with lower salinity, subtropical surface waters during MIS3, much as they did during the Holocene. Abrupt increases of

  14. Ocean Surface Water Sampling Devices.

    DTIC Science & Technology

    1963-10-01

    also parachuted, captures a volume of the water surface by a cookie cutter action and drew it into a 1-liter Thermos bottle for protection from...effective in landing upright on the water. Faster Dewar samplers without the cookie cutter action but with the same intake method proved about 95

  15. Age-Orientation Relationships of Northern Hemisphere Martian Gullies and "Pasted-on" Mantling Unit: Implications for Near-Surface Water Migration in Mars' Recent History

    NASA Technical Reports Server (NTRS)

    Bridges, N. T.; Lackner, C. N.

    2005-01-01

    The finding of abundant, apparently young, Martian gullies with morphologies indicative of formation by flowing fluid was surprising in that volumes of near-surface liquid water in sufficient quantities to modify the surface geology were not thought possible under current conditions. Original hypotheses on origin of gullies were mostly centered on groundwater seepage and surface runoff and melting of near-surface ground ice. More recently, melting of snow deposited in periods of higher obliquity has been proposed as a possible origin of the gullies. Tied to this hypothesis is the supposition that the "pasted-on" mantling unit observed in association with many gullies is composed of remnant snowpack. The mantling unit has distinct rounded edge on its upper boundary and exhibits features suggestive of flow noted that the uppermost part of the mantle marks where gullies begin, suggesting that the source of water for the gullies was within the mantle. The mantle is found preferentially on cold, pole-facing slopes and, where mantled and non-mantled slopes are found together, gullies are observed incised into the latter. In other cases, the mantling material lacks gullies.

  16. Impact of sedimentary degradation and deep water column production on GDGT abundance and distribution in surface sediments in the Arabian Sea: Implications for the TEX86 paleothermometer

    NASA Astrophysics Data System (ADS)

    Lengger, Sabine K.; Hopmans, Ellen C.; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2014-10-01

    The TEX86 is a widely used paleotemperature proxy based on isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs) produced by Thaumarchaeota. Archaeal membranes are composed of GDGTs with polar head groups (IPL-GDGTs), most of which are expected to be degraded completely or transformed into more recalcitrant core lipid (CL)-GDGTs upon cell lysis. Here, we examined the differences in concentration and distribution of core lipid (CL)- and intact polar lipid (IPL)-GDGTs in surface sediments at different deposition depths, and different oxygen bottom water concentrations (<3-83 μmol L-1). Surface sediments were sampled from 900 to 3000 m depth on a seamount (Murray Ridge), whose summit protrudes into the oxygen minimum zone of the Arabian Sea. Concentrations of organic carbon, IPL- and CL-GDGTs decreased linearly with increasing maximum residence time in the oxic zone of the sediment (tOZ), suggesting increasing sedimentary degradation of organic matter and GDGTs. IPL-GDGT-0 was the only exception and increased with tOZ, indicating that this GDGT was probably produced in situ in the surface sediment. Concentrations of crenarchaeol with glycosidic headgroups decreased with increasing tOZ, while crenarchaeol with a hexose, phosphohexose head (HPH) group, in contrast, showed an increase with increasing tOZ, indicating that the concentration of HPH crenarchaeol was primarily determined by in situ production in surficial sediments. TEX86 values of both IPL-derived GDGTs and CL-GDGTs decreased by ∼0.08 units with increasing water depth, in spite of the sea surface temperatures being identical for the restricted area studied. In situ production in sediments could be excluded as the main cause, due to the slow production rates of GDGTs in sediments, and previous observations of the same trends in TEX86 in sediment trap material. Instead, the incorporation of GDGTs produced in the oxygen minimum zone (with high TEX86 values) and their preferential degradation during

  17. Carbonate saturation state of surface waters in the Ross Sea and Southern Ocean: controls and implications for the onset of aragonite undersaturation

    NASA Astrophysics Data System (ADS)

    DeJong, H. B.; Dunbar, R. B.; Mucciarone, D.; Koweek, D. A.

    2015-12-01

    Predicting when surface waters of the Ross Sea and Southern Ocean will become undersaturated with respect to biogenic carbonate minerals is challenging in part due to the lack of baseline high-resolution carbon system data. Here we present ~ 1700 surface total alkalinity measurements from the Ross Sea and along a transect between the Ross Sea and southern Chile from the austral autumn (February-March 2013). We calculate the saturation state of aragonite (ΩAr) and calcite (Ω Ca) using measured total alkalinity and pCO2. In the Ross Sea and south of the Polar Front, variability in carbonate saturation state (Ω) is mainly driven by algal photosynthesis. Freshwater dilution and calcification have minimal influence on Ω variability. We estimate an early spring surface water ΩAr value of ~ 1.2 for the Ross Sea using a total alkalinity-salinity relationship and historical pCO2 measurements. Our results suggest that the Ross Sea is not likely to become undersaturated with respect to aragonite until the year 2070.

  18. Carbonate saturation state of surface waters in the Ross Sea and Southern Ocean: controls and implications for the onset of aragonite undersaturation

    NASA Astrophysics Data System (ADS)

    DeJong, H. B.; Dunbar, R. B.; Mucciarone, D. A.; Koweek, D. A.

    2015-06-01

    Predicting when surface waters of the Ross Sea and Southern Ocean will become undersaturated with respect to biogenic carbonate minerals is challenging in part due to the lack of baseline high resolution carbon system data. Here we present ~ 1700 surface total alkalinity measurements from the Ross Sea and along a transect between the Ross Sea and southern Chile from the austral autumn (February-March 2013). We calculate the saturation state of aragonite (ΩAr) and calcite (ΩCa) using measured total alkalinity and pCO2. In the Ross Sea and south of the Polar Front, variability in carbonate saturation state (Ω) is mainly driven by algal photosynthesis. Freshwater dilution and calcification have minimal influence on Ω variability. We estimate an early spring surface water ΩAr value of ~ 1.2 for the Ross Sea using a total alkalinity-salinity relationship and historical pCO2 measurements. Our results suggest that the Ross Sea is not likely to become undersaturated with respect to aragonite until the year 2070.

  19. Water and poverty: Implications for water planning

    NASA Astrophysics Data System (ADS)

    Fass, S. M.

    1993-07-01

    Although it recognizes the tangible economic benefits to health and income that may derive from greater safety of supply and improved time savings in procurement, planning for improvements of urban water systems in developing countries has overlooked other ways in which water may influence health and income among the poor. In these populations the price of water may further affect health and labor productivity, both directly through its impact on nutrition and indirectly through its impact on housing size and quality and on residential density. What at first might seem a straightforward equity issue in planning may thus be an issue of economic efficiency as well. Failure to account for the fuller range of tangible benefits associated with improvements in water supply may lead to underestimation of returns to investment and therefore to economically inefficient investment.

  20. Temperature Trends in the Tropical Upper Troposphere and Lower Stratosphere: Connections with Sea Surface Temperatures and Implications for Water Vapor and Ozone

    NASA Technical Reports Server (NTRS)

    Garfinkel, C. I.; Waugh, D. W.; Oman, L. D.; Wang, L.; Hurwitz, M. M.

    2013-01-01

    Satellite observations and chemistry-climate model experiments are used to understand the zonal structure of tropical lower stratospheric temperature, water vapor, and ozone trends. The warming in the tropical upper troposphere over the past 30 years is strongest near the Indo-Pacific warm pool, while the warming trend in the western and central Pacific is much weaker. In the lower stratosphere, these trends are reversed: the historical cooling trend is strongest over the Indo-Pacific warm pool and is weakest in the western and central Pacific. These zonal variations are stronger than the zonal-mean response in boreal winter. Targeted experiments with a chemistry-climate model are used to demonstrate that sea surface temperature (hereafter SST) trends are driving the zonal asymmetry in upper tropospheric and lower stratospheric tropical temperature trends. Warming SSTs in the Indian Ocean and in the warm pool region have led to enhanced moist heating in the upper troposphere, and in turn to a Gill-like response that extends into the lower stratosphere. The anomalous circulation has led to zonal structure in the ozone and water vapor trends near the tropopause, and subsequently to less water vapor entering the stratosphere. The radiative impact of these changes in trace gases is smaller than the direct impact of the moist heating. Projected future SSTs appear to drive a temperature and water vapor response whose zonal structure is similar to the historical response. In the lower stratosphere, the changes in water vapor and temperature due to projected future SSTs are of similar strength to, though slightly weaker than, that due directly to projected future CO2, ozone, and methane.

  1. A case study of field-scale maize irrigation patterns in western Nebraska: implications for water managers and recommendations for hyper-resolution land surface modeling

    NASA Astrophysics Data System (ADS)

    Gibson, Justin; Franz, Trenton E.; Wang, Tiejun; Gates, John; Grassini, Patricio; Yang, Haishun; Eisenhauer, Dean

    2017-02-01

    In many agricultural regions, the human use of water for irrigation is often ignored or poorly represented in land surface models (LSMs) and operational forecasts. Because irrigation increases soil moisture, feedback on the surface energy balance, rainfall recycling, and atmospheric dynamics is not represented and may lead to reduced model skill. In this work, we describe four plausible and relatively simple irrigation routines that can be coupled to the next generation of hyper-resolution LSMs operating at scales of 1 km or less. The irrigation output from the four routines (crop model, precipitation delayed, evapotranspiration replacement, and vadose zone model) is compared against a historical field-scale irrigation database (2008-2014) from a 35 km2 study area under maize production and center pivot irrigation in western Nebraska (USA). We find that the most yield-conservative irrigation routine (crop model) produces seasonal totals of irrigation that compare well against the observed irrigation amounts across a range of wet and dry years but with a low bias of 80 mm yr-1. The most aggressive irrigation saving routine (vadose zone model) indicates a potential irrigation savings of 120 mm yr-1 and yield losses of less than 3 % against the crop model benchmark and historical averages. The results of the various irrigation routines and associated yield penalties will be valuable for future consideration by local water managers to be informed about the potential value of irrigation saving technologies and irrigation practices. Moreover, the routines offer the hyper-resolution LSM community a range of irrigation routines to better constrain irrigation decision-making at critical temporal (daily) and spatial scales (< 1 km).

  2. Photochemical transformation of phenylurea herbicides in surface waters: a model assessment of persistence, and implications for the possible generation of hazardous intermediates.

    PubMed

    Fabbri, Debora; Minella, Marco; Maurino, Valter; Minero, Claudio; Vione, Davide

    2015-01-01

    This work models the phototransformation kinetics in surface waters of five phenylurea herbicides (diuron, fenuron, isoproturon, metoxuron and chlortoluron), for which important photochemical parameters are available in the literature (direct photolysis quantum yields and reaction rate constants with ·OH, CO3(-·) and the triplet states of chromophoric dissolved organic matter, (3)CDOM*). Model calculations suggest that isoproturon and metoxuron would be the least photochemically persistent and diuron the most persistent compound. Reactions with ·OH and (3)CDOM* would be the main phototransformation pathways for all compounds in the majority of environmental conditions. Reaction with CO3(-) could be important in waters with low dissolved organic carbon (DOC), while direct photolysis would be negligible for fenuron, quite important for chlortoluron, and somewhat significant for the other compounds. The direct photolysis of metoxuron and diuron is known to increase toxicity, and such a photoreaction pathway would be enhanced at intermediate DOC values (1-4 mg C L(1)). The reaction between phenylureas and ·OH is known to produce toxic intermediates, differently from (3)CDOM*. Therefore, the shift of reactivity from ·OH to (3)CDOM* with increasing DOC could reduce the environmental impact of photochemical transformation.

  3. Abrupt turnover in calcareous-nannoplankton assemblages across the Paleocene/Eocene Thermal Maximum: implications for surface-water oligotrophy over the Kerguelen Plateau, Southern Indian Ocean

    USGS Publications Warehouse

    Jiang, Shijun; Wise, Sherwood W.

    2007-01-01

    Ocean Drilling Program (ODP) Core Section 183-1135A-25R-4 from the Kerguelen Plateau in the Indian Ocean sector of the Southern Ocean represents only the second complete, expanded sequence through the Paleocene/Eocene Thermal Maximum (PETM; ~55 Ma) recovered from Antarctic waters. Calcareous nannoplankton at this site underwent an abrupt, fundamental turnover across the PETM as defined by a carbon isotope excursion. Although Chiasmolithus, Discoaster, and Fasciculithus exponentially increase in abundance at the onset, the former abruptly drops but then rapidly recovers, whereas the latter two taxa show opposite trends due to surface-water oligotrophy. These observations confirm previous results from ODP Site 690 on Maud Rise. The elevated pCO2 that accompanied the PETM caused a shoaling of the lysocline and carbonate compensation depth, leading to intensive dissolution of susceptible holococcoliths and poor preservation of the assemblages. Similarities and contrasts between the results of this study and previous work from open-ocean sites and shelf margins further demonstrate that the response to the PETM was consistent in open-ocean environments, but could be localized on continental shelves where nutrient regimes depend on the local geologic setting and oceanographic conditions.

  4. Density functional theory investigation of the interaction of water with α-Al2O3 and α-Fe2O3(11̲02) surfaces: Implications for surface reactivity

    NASA Astrophysics Data System (ADS)

    Aboud, Shela; Wilcox, Jennifer; Brown, Gordon E., Jr.

    2011-03-01

    Density functional theory calculations were performed in conjunction with ab initio thermodynamics, bond valence calculations, and density of states studies to investigate the chemical reactivity of α-Al2O3 and α-Fe2O3 (11¯02) surfaces in a humid environment. Isostructural α-Fe2O3 (11¯02) displays a much higher degree of surface reactivity with respect to water adsorption and aqueous heavy metal ions than α-Al2O3. The reason for these differences has not been fully explained. We have found that, while both metal oxides exhibit a similar stable (11¯02) surface at and below room temperature, corresponding to a stoichiometric surface with the first layer of metal ions missing, the degree of hydroxylation of the surface oxygen atoms leads to differences in the atomic layer relaxation in α-Al2O3 (11¯02) compared to α-Fe2O3 (11¯02), which has also been confirmed previously by crystal truncation rod x-ray diffraction studies. Also in agreement with these experimental studies, we find the atomic layer spacing of the most energetically stable (11̲02) Al2O3 surface is relatively insensitive to the inclusion of multiple layers of physisorbed water. This is in contrast to previously reported density functional theory studies of hydrated (11̲02) α-Fe2O3 surfaces, the results of which are confirmed in this work, that a monolayer of water is required for good agreement with experimental measurements of the atomic layer relaxation. These changes in atomic spacing result in changes in electron charge distributions and in Lewis and Brønsted acid/base properties of surface sites, which influence the relative reactivities of the two surfaces. However, the higher reactivity of the hydrated (11¯02) surface of α-Fe2O3 can be attributed mainly to the empty d states of the surface Fe atoms, which exhibit a first peak at ˜1 eV above the Fermi level and act as very strong Lewis acid sites. In comparison, the empty p states of Al in the hydrated (11¯02) α-Al2O3 surface

  5. Life Sciences Implications of Lunar Surface Operations

    NASA Technical Reports Server (NTRS)

    Chappell, Steven P.; Norcross, Jason R.; Abercromby, Andrew F.; Gernhardt, Michael L.

    2010-01-01

    The purpose of this report is to document preliminary, predicted, life sciences implications of expected operational concepts for lunar surface extravehicular activity (EVA). Algorithms developed through simulation and testing in lunar analog environments were used to predict crew metabolic rates and ground reaction forces experienced during lunar EVA. Subsequently, the total metabolic energy consumption, the daily bone load stimulus, total oxygen needed, and other variables were calculated and provided to Human Research Program and Exploration Systems Mission Directorate stakeholders. To provide context to the modeling, the report includes an overview of some scenarios that have been considered. Concise descriptions of the analog testing and development of the algorithms are also provided. This document may be updated to remain current with evolving lunar or other planetary surface operations, assumptions and concepts, and to provide additional data and analyses collected during the ongoing analog research program.

  6. Photochemical processes involving the UV absorber benzophenone-4 (2-hydroxy-4-methoxybenzophenone-5-sulphonic acid) in aqueous solution: reaction pathways and implications for surface waters.

    PubMed

    De Laurentiis, Elisa; Minella, Marco; Sarakha, Mohamed; Marrese, Alessandro; Minero, Claudio; Mailhot, Gilles; Brigante, Marcello; Vione, Davide

    2013-10-01

    The sunlight filter benzophenone-4 (BP-4) is present in surface waters as two prevailing forms, the singly deprotonated (HA-) and the doubly deprotonated one (A(2-)), with pKa2 = 7.30 ± 0.14 (μ ± σ, by dissociation of the phenolic group). In freshwater environments, BP-4 would mainly undergo degradation by reaction with ·OH and direct photolysis. The form HA(-) has a second-order reaction rate constant with ·OH (k(·OH)) of (1.87 ± 0.31)·10(10) M(-1) s(-1) and direct photolysis quantum yield Φ equal to (3.2 ± 0.6)·10(-5). The form A(2-) has (8.46 ± 0.24)·10(9) M(-1) s(-1) as the reaction rate constant with ·OH and (7.0 ± 1.3)·10(-5) as the photolysis quantum yield. The direct photolysis of HA(-) likely proceeds via homolytic breaking of the O-H bond of the phenolic group to give the corresponding phenoxy radical, as suggested by laser flash photolysis experiments. Photochemical modelling shows that because of more efficient direct photolysis (due to both higher sunlight absorption and higher photolysis quantum yield), the A(2-) form can be degraded up to 3 times faster than HA(-) in surface waters. An exception is represented by low-DOC (dissolved organic carbon) conditions, where the ·OH reaction dominates degradation and the transformation kinetics of HA(-) is faster compared to A(2-). The half-life time of BP-4 in mid-latitude summertime would be in the range of days to weeks, depending on the environmental conditions. BP-4 also reacts with Br2(·-), and a rate constant k(Br2(·-),BP-4) = (8.05 ± 1.33)·10(8) M(-1) s(-1) was measured at pH 7.5. Model results show that reaction with Br2(·-) could be a potentially important transformation pathway of BP-4 in bromide-rich (e.g. seawater) and DOM-rich environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Experimental determination of cadmium uptake in shells of the planktonic foraminifera Orbulina universa and Globigerina bulloides : Implications for surface water paleoreconstructions

    NASA Astrophysics Data System (ADS)

    Mashiotta, Tracy A.; Lea, David W.; Spero, Howard J.

    1997-10-01

    Laboratory culturing is a direct means of determining Cd uptake in shells of planktonic foraminifera. We employed a new stable isotope technique using both 110Cd and 111Cd to assess uptake in the symbiont bearing species, Orbulina universa, and the nonsymbiont bearing species, Globigerina bulloides. In certain experiments with G. bulloides the three endmember isotope dilution method was combined with a recently described 48Ca labeling technique. Shells of Orbulina universa cultured under a 12 h high light:12 h dark cycle are found to incorporate very little Cd. Foraminifera can be induced to take up slightly more Cd by growth under 24 h darkness or under a 12 h high light:12 h dark cycle with exposure to the photosynthesis inhibitor, DCMU. These results demonstrate that O. universa under-represents the Cd concentration of seawater in which the shell is precipitated. Additionally, the results suggest a previously unknown influence of symbiotic dinoflagellates on foraminiferal shell chemistry. There are two different mechanisms by which symbionts might play a role in influencing Cd uptake in O. universa: (1) algal sequestration and removal of Cd from the foraminiferal calcification microenvironment or (2) photosynthetic enhancement of calcification rate, leading to Cd exclusion. If these results apply generally to bioactive trace metal uptake by dinoflagellate-bearing planktonic foraminifera, they suggest that shells of species such as O. universa only record qualitative changes in surface water metal concentrations. The response for Cd uptake in nonsymbiont bearing G. bulloides (cultured under a 12 h high light: 12 h dark cycle) appears linear within and slightly above the range of Cd concentrations found in the modern ocean, with an effective partition coefficient equal to 1.9 ± 0.2 (95% C.I.). The Cd partition coefficient determined for G. bulloides falls within the range of DCd previously found for fossil benthic foraminifera but is twenty times higher than that

  8. Sulfate deposition to surface waters

    SciTech Connect

    Henriksen, A.; Brakke, D.F.

    1988-01-01

    Critical loads are the highest deposition of strong acid anions in surface waters that will not cause harmful biological effects on populations, such as declines in or extinctions of fish. Our analysis focuses on sulfate deposition because in glaciated regions sulfate is conservative in soils, whereas nitrate in biologically cycled. Sulfate also is the dominant anion in acidic deposition and in most acidic lakes. This analysis, represents the first evaluation of certain data available from Norway and the eastern United States, with an emphasis on the data from Scandinavia. The concept of dose-response is widely used in connection with water pollution. Any lake system subjected to an external dose of pollutants will have an internal resistance (or buffer capacity) to the change. The response of the lake system will depend on the relative magnitudes of the dose and the resistance parameters.

  9. Water molecules orientation in surface layer

    NASA Astrophysics Data System (ADS)

    Klingo, V. V.

    2000-08-01

    The water molecules orientation has been investigated theoretically in the water surface layer. The surface molecule orientation is determined by the direction of a molecule dipole moment in relation to outward normal to the water surface. Entropy expressions of the superficial molecules in statistical meaning and from thermodynamical approach to a liquid surface tension have been found. The molecules share directed opposite to the outward normal that is hydrogen protons inside is equal 51.6%. 48.4% water molecules are directed along to surface outward normal that is by oxygen inside. A potential jump at the water surface layer amounts about 0.2 volts.

  10. Interaction Of Water Molecules With SiC(001) Surfaces

    SciTech Connect

    Cicero, G; Catellani, A; Galli, G

    2004-08-10

    We have investigated the interaction of water molecules with the polar Si- and C- terminated surfaces of cubic Silicon Carbide by means of ab initio molecular dynamics simulations at finite temperature. Different water coverages were considered, from {1/4} to a complete monolayer. Irrespective of coverage, we find that water dissociates on the silicon terminated surfaces, leading to important changes in both its structural and electronic properties. On the contrary, the carbon terminated surface remains inert when exposed to water. We propose experiments to reveal the ionic and electronic structure of wet Si-terminated surfaces predicted by our calculations, which at full coverage are notably different from those of hydrated Si(001) substrates. Finally, we discuss the implications of our results for SiC surface functionalization.

  11. Large-scale hydrological modeling for calculating water stress indices: implications of improved spatiotemporal resolution, surface-groundwater differentiation, and uncertainty characterization.

    PubMed

    Scherer, Laura; Venkatesh, Aranya; Karuppiah, Ramkumar; Pfister, Stephan

    2015-04-21

    Physical water scarcities can be described by water stress indices. These are often determined at an annual scale and a watershed level; however, such scales mask seasonal fluctuations and spatial heterogeneity within a watershed. In order to account for this level of detail, first and foremost, water availability estimates must be improved and refined. State-of-the-art global hydrological models such as WaterGAP and UNH/GRDC have previously been unable to reliably reflect water availability at the subbasin scale. In this study, the Soil and Water Assessment Tool (SWAT) was tested as an alternative to global models, using the case study of the Mississippi watershed. While SWAT clearly outperformed the global models at the scale of a large watershed, it was judged to be unsuitable for global scale simulations due to the high calibration efforts required. The results obtained in this study show that global assessments miss out on key aspects related to upstream/downstream relations and monthly fluctuations, which are important both for the characterization of water scarcity in the Mississippi watershed and for water footprints. Especially in arid regions, where scarcity is high, these models provide unsatisfying results.

  12. Effect of Water on the Surface Composition of Irradiated Minerals

    NASA Astrophysics Data System (ADS)

    Dukes, C. A.; Baragiola, R. A.

    2010-03-01

    Sections of olivine and augite exposed to 10^17 Ar cm-2 ion irradiation and then rinsed in water or exposed to a humid enviornment show up to 60% depletion of surface cations. This has implications for sample return and curation.

  13. Surface water discharges from onshore stripper wells.

    SciTech Connect

    Veil, J. A.

    1998-01-16

    Under current US Environmental Protection Agency (EPA) rules, small onshore oil producers are allowed to discharge produced water to surface waters with approval from state agencies; but small onshore gas producers, however, are prohibited from discharging produced water to surface waters. The purpose of this report is to identify those states that allow surface water discharges from small onshore oil operations and to summarize the types of permitting controls they use. It is intended that the findings of this report will serve as a rationale to encourage the EPA to revise its rules and to remove the prohibition on surface water discharges from small gas operations.

  14. Water availability as a driver of spatial and temporal variability in vegetation in the La Mancha plain (Spain): Implications for the land-surface energy, water and carbon budget

    NASA Astrophysics Data System (ADS)

    Los, Sietse

    2017-04-01

    Vegetation is water limited in large areas of Spain and therefore a close link exists between vegetation greenness observed from satellite and moisture availability. Here we exploit this link to infer spatial and temporal variability in moisture from MODIS NDVI data and thermal data. Discrepancies in the precipitation - vegetation relationship indicate areas with an alternative supply of water (i.e. not rainfall), this can be natural where moisture is supplied by upwelling groundwater, or can be artificial where crops are irrigated. As a result spatial and temporal variability in vegetation in the La Mancha Plain appears closely linked to topography, geology, rainfall and land use. Crop land shows large variability in year-to-year vegetation greenness; for some areas this variability is linked to variability in rainfall but in other cases this variability is linked to irrigation. The differences in irrigation treatment within one plant functional type, in this case crops, will lead to errors in land surface models when ignored. The magnitude of these effects on the energy, carbon and water balance are assessed at the scale of 250 m to 200 km. Estimating the water balance correctly is of particular important since in some areas in Spain more water is used for irrigation than is supplemented by rainfall.

  15. The implications of water quality in hemodialysis.

    PubMed

    Hoenich, Nicholas A; Levin, Robert

    2003-01-01

    Water used in dialysis requires additional treatment to minimize patient exposure to potential contaminants that may be present in drinking water. Although standards for the chemical purity of water are in existence and have eliminated many of the problems seen in renal units in the 1970s, some problems remain, and the importance of newer contaminants arising from changes in water treatment at the municipal level are being recognized. Despite this, recent surveys have indicated considerable shortcomings in compliance with chemical standards. The water quality used in the preparation of dialysis fluid also requires minimal bacterial content. Staff working in renal units are frequently unaware of the level of microbiologic contamination in their dialysis fluid arising from the presence of biofilm in the dialysis machines and the water distribution network. Bacterial fragments generated by such biofilms are able to cross the dialysis membrane and stimulate an inflammatory response in the patient. Such inflammation has been implicated in the mortality and morbidity associated with dialysis. The desire to improve treatment outcomes has led to the application of more stringent standards for the microbiologic purity of dialysis fluid and to the introduction of ultraclean dialysis fluid into clinical practice.

  16. Wastewater indicator compounds in wastewater effluent, surface water, and bed sediment in the St. Croix National Scenic Riverway and implications for water resources and aquatic biota, Minnesota and Wisconsin, 2007-08

    USGS Publications Warehouse

    Tomasek, Abigail A.; Lee, Kathy E.; Hansen, Donald S.

    2012-01-01

    The results of this study indicate that aquatic biota in the St. Croix River are exposed to a wide variety of organic contaminants that originate from diverse sources including WWTP effluent. The data on wastewater indicator compounds indicate that exposures are temporally and spatially variable and that OWCs may accumulate in bed sediment. These results also indicate that OWCs in water and bed sediment increase downstream from discharges of wastewater effluent to the St. Croix River; however, the presence of OWCs in surface water and bed sediment at the Sunrise site indicates that potential sources of compounds, such as WWTPs or other sources, are upstream from the Taylors Falls-St. Croix Falls area.

  17. Water surface capturing by image processing

    USDA-ARS?s Scientific Manuscript database

    An alternative means of measuring the water surface interface during laboratory experiments is processing a series of sequentially captured images. Image processing can provide a continuous, non-intrusive record of the water surface profile whose accuracy is not dependent on water depth. More trad...

  18. Ground water and surface water; a single resource

    USGS Publications Warehouse

    Winter, Thomas C.; Harvey, Judson W.; Franke, O. Lehn; Alley, William M.

    1998-01-01

    The importance of considering ground water and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently. The interaction of ground water and surface water has been shown to be a significant concern in many of these issues. Contaminated aquifers that discharge to streams can result in long-term contamination of surface water; conversely, streams can be a major source of contamination to aquifers. Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure. The purpose of this report is to present our current understanding of these processes and activities as well as limitations in our knowledge and ability to characterize them.

  19. Langmuir circulation inhibits near-surface water turbulence

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2012-07-01

    In the surface ocean, breaking waves are a major source of air bubbles and turbulent kinetic energy. During the presence of a consistent surface wind, these wave-generated bubbles, along with other surface material like seaweed or foam, can be drawn into long rows along the surface. Driving this organization is Langmuir circulation, a phenomenon in which the wind and waves cause surface waters to rotate helically, moving like a wire wrapped around a pole in the windward direction. These spiral currents oscillate between clockwise and counterclockwise rotations, such that in some places the surface waters are pushed together and in others they are pulled apart. Researchers have previously found that at sites of convergence the bubbles produced by breaking waves are pushed to depths of 15 meters or more, with important implications for air-sea gas mixing and other processes.

  20. Changing surface water conditions for the last 500 ka in the Southeast Atlantic: Implications for variable influences of Agulhas leakage and Benguela upwelling

    NASA Astrophysics Data System (ADS)

    Petrick, Benjamin F.; McClymont, Erin L.; Marret, Fabienne; Meer, Marcel T. J.

    2015-09-01

    The Southeast Atlantic Ocean is an important component of global ocean circulation, as it includes heat and salt transfer into the Atlantic through the Agulhas leakage as well as the highly productive Benguela upwelling system. Here we reconstruct sea surface temperatures (SSTs) from Ocean Drilling Program (ODP) Site 1087 in the Southeast Atlantic to investigate surface ocean circulation patterns during the late Pleistocene (0-500 ka). The UK'37 index and dinoflagellate cyst assemblages are used to reconstruct SSTs, δDalkenone is used to reconstruct changes in sea surface salinity, and mass accumulation rates of alkenones and chlorine pigments are quantified to detect changing marine export productivity. The greatest amplitude of SST warming precedes decreases in benthic δ18O and therefore occurs early in the transition from glacials to interglacials. The δDalkenone, as a salinity indicator, increases before SSTs, suggesting that the pattern of Agulhas leakage is more complex than suggested by SST proxies. Marine isotope stage (MIS) 10 shows an anomalous pattern: it is marked by a pronounced increase in chlorine concentration, which may be related to enhanced/expanded Benguela upwelling reaching the core site. We find no evidence of an absence of Agulhas leakage throughout the record, suggesting that there is no Agulhas cutoff even during MIS 10. Finally, the ODP Site 1087 record shows an increasing strength of Agulhas leakage towards the present day, which may have impacted the intensity of the Atlantic meridional overturning circulation. As a result, the new analyses from ODP Site 1087 demonstrate a complex interaction between influences of the Benguela upwelling and the Agulhas leakage through the late Pleistocene, which are inferred here to reflect changing circulation patterns in the Southern Ocean and in the atmosphere.

  1. Surface Water Treatment Rules State Implementation Guidance

    EPA Pesticide Factsheets

    These documents provide guidance to states, tribes and U.S. EPA Regions exercising primary enforcement responsibility under the Safe Drinking Water Act. The documents contain EPA’s recommendations for implementation of the Surface Water Treatment Rules.

  2. Hydrology: The dynamics of Earth's surface water

    NASA Astrophysics Data System (ADS)

    Yamazaki, Dai; Trigg, Mark A.

    2016-12-01

    High-resolution satellite mapping of Earth's surface water during the past 32 years reveals changes in the planet's water systems, including the influence of natural cycles and human activities. See Letter p.418

  3. Interaction between water and defective silica surfaces

    SciTech Connect

    Chen Yunwen; Cheng Haiping

    2011-03-21

    We use the density functional theory method to study dry (1 x 1) {alpha}-quartz (0001) surfaces that have Frenkel-like defects such as oxygen vacancy and oxygen displacement. These defects have distinctively different effects on the water-silica interface depending on whether the adsorbent is a single water molecule, a cluster, or a thin film. The adsorption energies, bonding energies, and charge transfer or redistributions are analyzed, from which we find that the existence of a defect enhances the water molecule and cluster surface interaction by a large amount, but has little or even negative effect on water thin film-silica surface interaction. The origin of the weakening in film-surface systems is the collective hydrogen bonding that compromises the water-surface interaction in the process of optimizing the total energy. For clusters on surfaces, the lowest total energy states lower both the bonding energy and the adsorption energy.

  4. Multi-day near-surface stratification in tropical waters

    NASA Astrophysics Data System (ADS)

    Fischer, Tim; Kock, Annette; Dengler, Marcus; Brandt, Peter; Karstensen, Johannes; Arévalo-Martínez, Damian L.; Bange, Hermann W.

    2017-04-01

    The near-surface layer of the tropical oceans is known for the occurrence of temporal stratification in the upper few meters, which can lead to vertical gradients in water properties and prompts questions about correct estimation of air-sea exchange of gases but similarly of momentum, heat, water vapour, and other matter. Here we present observations in the near-surface layer of the Peruvian upwelling regime and of the tropical Atlantic Ocean below the Intertropical Convergence Zone, which show near-surface stratification events that frequently have a lifetime of several days. This aspect extends the predominant notion of a diurnal near-surface pycnocline that appears, migrates and disappears in a diurnal cycle, and is superposed on a background surface mixed layer. Near-surface stratification suppresses turbulent mixing and subsequently isolates or traps overlying water, which eventually generates vertical gradients of water properties. Multi-day near-surface stratification and associated multi-day trapping of a thin near-surface layer may enhance such vertical gradients in comparison to diurnal trapping. We explore the implications of multi-day trapping, particularly for estimates of air-sea gas exchange. For example, in the Peruvian upwelling regime in austral summer 2012/13, strong near-surface vertical gradients of nitrous oxide concentration were observed which most likely resulted from multi-day trapping. Here, applying standard routines for air-sea gas exchange leads to a systematic overestimation of regionwide nitrous oxide emission by 30%.

  5. Streaks Of Colored Water Indicate Surface Airflows

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.

    1994-01-01

    Response faster and contamination less than in oil-flow technique. Flowing colored water provides accurate and clean way to reveal flows of air on surfaces of models in wind tunnels. Colored water flows from small orifices in model, forming streak lines under influence of air streaming over surface of model.

  6. Streaks Of Colored Water Indicate Surface Airflows

    NASA Technical Reports Server (NTRS)

    Wilcox, Floyd J., Jr.

    1994-01-01

    Response faster and contamination less than in oil-flow technique. Flowing colored water provides accurate and clean way to reveal flows of air on surfaces of models in wind tunnels. Colored water flows from small orifices in model, forming streak lines under influence of air streaming over surface of model.

  7. Gray solitons on the surface of water.

    PubMed

    Chabchoub, A; Kimmoun, O; Branger, H; Kharif, C; Hoffmann, N; Onorato, M; Akhmediev, N

    2014-01-01

    The dynamics of surface gravity water waves can be described by the self-defocusing nonlinear Schrödinger equation. Recent observations of black solitons on the surface of water confirmed its validity for finite, below critical depth. The black soliton is a limiting case of a family of gray soliton solutions with finite amplitude depressions. Here, we report observations of gray solitons in water waves, thus, complementing our previous observations of black solitons.

  8. Pesticide mitigation strategies for surface water quality

    USDA-ARS?s Scientific Manuscript database

    Pesticide residues are being increasingly detected in surface water in agricultural and urban areas. In some cases water bodies are being listed under the Clean Water Act 303(d) as impaired and Total Maximum Daily Loads are required to address the impairments in agricultural areas. Pesticides in sur...

  9. Municipal Wastewater Treatment Plant Biosludge Applications and Perfluoroalkyl Acid Surface Water Contamination in North Carolina

    EPA Science Inventory

    Implications and Questions- Perfluorinated compounds at high concentrations in sludges, on fields, in surface water in areas receiving sludge applications-Urban and suburban sludges typically disposed of in rural locations, usually marketed as “free fertilizer” becaus...

  10. Municipal Wastewater Treatment Plant Biosludge Applications and Perfluoroalkyl Acid Surface Water Contamination in North Carolina

    EPA Science Inventory

    Implications and Questions- Perfluorinated compounds at high concentrations in sludges, on fields, in surface water in areas receiving sludge applications-Urban and suburban sludges typically disposed of in rural locations, usually marketed as “free fertilizer” becaus...

  11. A Review of Surface Water Quality Models

    PubMed Central

    Li, Shibei; Jia, Peng; Qi, Changjun; Ding, Feng

    2013-01-01

    Surface water quality models can be useful tools to simulate and predict the levels, distributions, and risks of chemical pollutants in a given water body. The modeling results from these models under different pollution scenarios are very important components of environmental impact assessment and can provide a basis and technique support for environmental management agencies to make right decisions. Whether the model results are right or not can impact the reasonability and scientificity of the authorized construct projects and the availability of pollution control measures. We reviewed the development of surface water quality models at three stages and analyzed the suitability, precisions, and methods among different models. Standardization of water quality models can help environmental management agencies guarantee the consistency in application of water quality models for regulatory purposes. We concluded the status of standardization of these models in developed countries and put forward available measures for the standardization of these surface water quality models, especially in developing countries. PMID:23853533

  12. A review of surface water quality models.

    PubMed

    Wang, Qinggai; Li, Shibei; Jia, Peng; Qi, Changjun; Ding, Feng

    2013-01-01

    Surface water quality models can be useful tools to simulate and predict the levels, distributions, and risks of chemical pollutants in a given water body. The modeling results from these models under different pollution scenarios are very important components of environmental impact assessment and can provide a basis and technique support for environmental management agencies to make right decisions. Whether the model results are right or not can impact the reasonability and scientificity of the authorized construct projects and the availability of pollution control measures. We reviewed the development of surface water quality models at three stages and analyzed the suitability, precisions, and methods among different models. Standardization of water quality models can help environmental management agencies guarantee the consistency in application of water quality models for regulatory purposes. We concluded the status of standardization of these models in developed countries and put forward available measures for the standardization of these surface water quality models, especially in developing countries.

  13. Water vapor retrieval over many surface types

    SciTech Connect

    Borel, C.C.; Clodius, W.C.; Johnson, J.

    1996-04-01

    In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

  14. Surface Water Treatment Workshop Manual.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    This manual was developed for use at workshops designed to increase the knowledge of experienced water treatment plant operators. Each of the fourteen lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in this manual include: basic water…

  15. Surface Water Treatment Workshop Manual.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    This manual was developed for use at workshops designed to increase the knowledge of experienced water treatment plant operators. Each of the fourteen lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in this manual include: basic water…

  16. Shallow water sound propagation with surface waves.

    PubMed

    Tindle, Chris T; Deane, Grant B

    2005-05-01

    The theory of wavefront modeling in underwater acoustics is extended to allow rapid range dependence of the boundaries such as occurs in shallow water with surface waves. The theory allows for multiple reflections at surface and bottom as well as focusing and defocusing due to reflection from surface waves. The phase and amplitude of the field are calculated directly and used to model pulse propagation in the time domain. Pulse waveforms are obtained directly for all wavefront arrivals including both insonified and shadow regions near caustics. Calculated waveforms agree well with a reference solution and data obtained in a near-shore shallow water experiment with surface waves over a sloping bottom.

  17. Evidence for water structuring forces between surfaces

    SciTech Connect

    Stanley, Christopher B; Rau, Dr. Donald

    2011-01-01

    Structured water on apposing surfaces can generate significant energies due to reorganization and displacement as the surfaces encounter each other. Force measurements on a multitude of biological structures using the osmotic stress technique have elucidated commonalities that point toward an underlying hydration force. In this review, the forces of two contrasting systems are considered in detail: highly charged DNA and nonpolar, uncharged hydroxypropyl cellulose. Conditions for both net repulsion and attraction, along with the measured exclusion of chemically different solutes from these macromolecular surfaces, are explored and demonstrate features consistent with a hydration force origin. Specifically, the observed interaction forces can be reduced to the effects of perturbing structured surface water.

  18. Subsurface And Surface Water Flow Interactions

    EPA Science Inventory

    In this chapter we present basic concepts and principles underlying the phenomena of groundwater and surface water interactions. Fundamental equations and analytical and numerical solutions describing stream-aquifer interactions are presented in hillslope and riparian aquifer en...

  19. Clean Air Markets - Monitoring Surface Water Chemistry

    EPA Pesticide Factsheets

    Learn about how EPA uses Long Term Monitoring (LTM) and Temporily Integrated Monitoring of Ecosystems (TIME) to track the effect of the Clean Air Act Amendments on acidity of surface waters in the eastern U.S.

  20. Subsurface And Surface Water Flow Interactions

    EPA Science Inventory

    In this chapter we present basic concepts and principles underlying the phenomena of groundwater and surface water interactions. Fundamental equations and analytical and numerical solutions describing stream-aquifer interactions are presented in hillslope and riparian aquifer en...

  1. Surface processing using water cluster ion beams

    NASA Astrophysics Data System (ADS)

    Takaoka, Gikan H.; Ryuto, Hiromichi; Takeuchi, Mitsuaki; Ichihashi, Gaku

    2013-07-01

    Vaporized water clusters were produced by an adiabatic expansion phenomenon, and various substrates such as Si(1 0 0), SiO2, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polycarbonate (PC) were irradiated by water cluster ion beams. The sputtered depth increased with increasing acceleration voltage, and the sputtering rate was much larger than that obtained using Ar monomer ion irradiation. The sputtering yield for PMMA was approximately 200 molecules per ion, at an acceleration voltage of 9 kV. X-ray photoelectron spectroscopy (XPS) measurements showed that high-rate sputtering for the PMMA surface can be ascribed to the surface erosion by the water cluster ion irradiation. Furthermore, the micropatterning was demonstrated on the PMMA substrate. Thus, the surface irradiation by water cluster ion beams exhibited a chemical reaction based on OH radicals, as well as excited hydrogen atoms, which resulted in a high sputtering rate and low irradiation damage of the substrate surfaces.

  2. The Dynamic Surface Tension of Water

    PubMed Central

    2017-01-01

    The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m–1) than under equilibrium conditions (∼72 mN m–1) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments. PMID:28301160

  3. The Dynamic Surface Tension of Water.

    PubMed

    Hauner, Ines M; Deblais, Antoine; Beattie, James K; Kellay, Hamid; Bonn, Daniel

    2017-03-23

    The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m(-1)) than under equilibrium conditions (∼72 mN m(-1)) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments.

  4. Water desorption from nanostructured graphite surfaces.

    PubMed

    Clemens, Anna; Hellberg, Lars; Grönbeck, Henrik; Chakarov, Dinko

    2013-12-21

    Water interaction with nanostructured graphite surfaces is strongly dependent on the surface morphology. In this work, temperature programmed desorption (TPD) in combination with quadrupole mass spectrometry (QMS) has been used to study water ice desorption from a nanostructured graphite surface. This model surface was fabricated by hole-mask colloidal lithography (HCL) along with oxygen plasma etching and consists of a rough carbon surface covered by well defined structures of highly oriented pyrolytic graphite (HOPG). The results are compared with those from pristine HOPG and a rough (oxygen plasma etched) carbon surface without graphite nanostructures. The samples were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The TPD experiments were conducted for H2O coverages obtained after exposures between 0.2 and 55 langmuir (L) and reveal a complex desorption behaviour. The spectra from the nanostructured surface show additional, coverage dependent desorption peaks. They are assigned to water bound in two-dimensional (2D) and three-dimensional (3D) hydrogen-bonded networks, defect-bound water, and to water intercalated into the graphite structures. The intercalation is more pronounced for the nanostructured graphite surface in comparison to HOPG surfaces because of a higher concentration of intersheet openings. From the TPD spectra, the desorption energies for water bound in 2D and 3D (multilayer) networks were determined to be 0.32 ± 0.06 and 0.41 ± 0.03 eV per molecule, respectively. An upper limit for the desorption energy for defect-bound water was estimated to be 1 eV per molecule.

  5. Mars water vapor, near-surface

    NASA Technical Reports Server (NTRS)

    Ryan, J. A.; Sharman, R. D.; Lucich, R. D.

    1982-01-01

    In a previous paper we concluded that the temperature sensors aboard the Viking landers (VL-1 and VL-2) were detecting the water vapor frost point. Analysis of one Mars year of data at both lander sites substantiates this conclusion. At VL-1 it is found that the water vapor mixing ratio is constant with height through the bulk of the atmosphere, most of the time. Exceptions are during the onset phases of the two major dust storms when temporary enhancement of near-surface vapor occurs (the same phenomenon is observed at VL-2), and some depletion of near-surface vapor during the decay phase of the first storm, possibly the second storm as well. The former suggests near-surface, northward transport of water vapor with the storms. The latter suggests adsorption of vapor on dust particles followed by surface deposition. At VL-2, severe near-surface depletion of water vapor occurs during northern autumn and winter. The residual vapor is in equilibrium with the surface condensate observed at the site during this period, indicating that the source region for the condensate must be aloft with downward transport by dust fall-out. Since the near-surface water vapor mixing ratio and concentration at VL-1 generally parallels the column abundance over VL-1 obtained by the orbiters, this suggests that VL-1 can be used to give a measure of column abundance for as long as the temperature sensors remain operational.

  6. Mars water vapor, near-surface

    NASA Technical Reports Server (NTRS)

    Ryan, J. A.; Sharman, R. D.; Lucich, R. D.

    1982-01-01

    In a previous paper we concluded that the temperature sensors aboard the Viking landers (VL-1 and VL-2) were detecting the water vapor frost point. Analysis of one Mars year of data at both lander sites substantiates this conclusion. At VL-1 it is found that the water vapor mixing ratio is constant with height through the bulk of the atmosphere, most of the time. Exceptions are during the onset phases of the two major dust storms when temporary enhancement of near-surface vapor occurs (the same phenomenon is observed at VL-2), and some depletion of near-surface vapor during the decay phase of the first storm, possibly the second storm as well. The former suggests near-surface, northward transport of water vapor with the storms. The latter suggests adsorption of vapor on dust particles followed by surface deposition. At VL-2, severe near-surface depletion of water vapor occurs during northern autumn and winter. The residual vapor is in equilibrium with the surface condensate observed at the site during this period, indicating that the source region for the condensate must be aloft with downward transport by dust fall-out. Since the near-surface water vapor mixing ratio and concentration at VL-1 generally parallels the column abundance over VL-1 obtained by the orbiters, this suggests that VL-1 can be used to give a measure of column abundance for as long as the temperature sensors remain operational.

  7. Water drop friction on superhydrophobic surfaces.

    PubMed

    Olin, Pontus; Lindström, Stefan B; Pettersson, Torbjörn; Wågberg, Lars

    2013-07-23

    To investigate water drop friction on superhydrophobic surfaces, the motion of water drops on three different superhydrophobic surfaces has been studied by allowing drops to slide down an incline and capturing their motion using high-speed video. Two surfaces were prepared using crystallization of an alkyl ketene dimer (AKD) wax, and the third surface was the leaf of a Lotus (Nelumbo Nucifera). The acceleration of the water droplets on these superhydrophobic surfaces was measured as a function of droplet size and inclination of the surface. For small capillary numbers, we propose that the energy dissipation is dominated by intermittent pinning-depinning transitions at microscopic pinning sites along the trailing contact line of the drop, while at capillary numbers exceeding a critical value, energy dissipation is dominated by circulatory flow in the vicinity of the contacting disc between the droplet and the surface. By combining the results of the droplet acceleration with a theoretical model based on energy dissipation, we have introduced a material-specific coefficient called the superhydrophobic sliding resistance, b(sh). Once determined, this parameter is sufficient for predicting the motion of water drops on superhydrophobic surfaces of a general macroscopic topography. This theory also infers the existence of an equilibrium sliding angle, β(eq), at which the drop acceleration is zero. This angle is decreasing with the radius of the drop and is in quantitative agreement with the measured tilt angles required for a stationary drop to start sliding down an incline.

  8. Adsorption of natural organic matter and disinfection byproduct precursors from surface water onto TiO2 nanoparticles: pH effects, isotherm modelling and implications for using TiO2 for drinking water treatment.

    PubMed

    Gora, Stephanie L; Andrews, Susan A

    2017-05-01

    Titanium dioxide is a photocatalyst that can remove organic contaminants of interest to the drinking water treatment industry, including natural organic matter (NOM) and disinfection byproduct (DBP) precursors. The photocatalytic reaction occurs in two steps: adsorption of the contaminant followed by degradation of the adsorbed contaminant upon irradiation with UV light. The second part of this process can lead to the formation of reactive intermediates and negative impacts on treated water quality, such as increased DBP formation potential (DBPfp). Adsorption alone does not result in the formation of reactive intermediates and thus may prove to be a safe way to incorporate TiO2 into drinking water treatment processes. The goal of this study was to expand on the current understanding of NOM adsorption on TiO2 and examine it in a drinking water context by observing NOM adsorption from real water sources and evaluating the effects of the resulting reductions on the DBPfp of the treated water. Bottle point isotherm tests were conducted with raw water from two Canadian water treatment plants adjusted to pH 4, pH 6 and pH 8 and dosed with TiO2 nanoparticles. The DOC results were a good fit to a modified Freundlich isotherm. DBP precursors and liquid chromatography with organic carbon detection NOM fractions associated with DBP formation were removed to some extent at all pHs, but most effectively at pH 4.

  9. Surface, Water and Air Biocharacterization (SWAB)

    NASA Image and Video Library

    2009-08-18

    ISS020-E-031558 (18 Aug. 2009) --- NASA astronaut Michael Barratt, Expedition 20 flight engineer, conducts a Surface, Water and Air Biocharacterization (SWAB) water sampling from the Potable Water Dispenser (PWD) in the Destiny laboratory of the International Space Station. SWAB uses advanced molecular techniques to comprehensively evaluate microbes onboard the space station, including pathogens (organisms that may cause disease). This study will allow an assessment of the risk of microbes to the crew and the spacecraft.

  10. Recent changes in surface water extent over the Northern latitudes.

    NASA Astrophysics Data System (ADS)

    Papa, F.; Prigent, C.; Rossow, W. B.

    2009-04-01

    All climate scenarios agree on the high sensitivity of the northern regions to global change, with a stronger warming at these latitudes than globally. Continued warming will likely have profound consequences for many continental systems throughout the region. In particular, an increase in air temperature is expected to intensify the Arctic hydrological cycle. As a key parameter of the global biogeochemical and hydrological cycles, terrestrial surface waters (rivers, lakes, man-made reservoirs, wetlands and episodically inundation) are of a particular importance because they interact directly with the ocean and atmosphere. Using a multi-satellite method, including passive microwave land surface emissivities, along with active microwave, visible and near infrared observations developed to estimate inundated area at global scale, we present here the recent changes observed in surface water extent in Northern latitudes over the period 1993-2004. Over these regions, results show a decline in surface water extent with large geographical contrasts between Eurasia and America, between the different large river basins and between the regions underlain or not by permafrost. For six major basins located in Eurasia and North America, we analyze theses changes in comparison with precipitation, temperature and in-situ river discharge variations. The Yenissey and the Lena river basins, which are largely underlain by permafrost, show the largest changes in surface water extent especially in July/August with a decline of about 1-2% per year. Our results support the idea that more deeply thawed permafrost, due to temperature increase in the Boreal regions, would promote increased soil infiltration and a possible shift of water storage from the surface/near surface to the subsurface. The implications of these results in term of energy, biochemical and water cycles will be discussed.

  11. Bulk water freezing dynamics on superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

    2017-01-01

    In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm < Lc < 6 mm) using carefully designed freezing experiments in a temperature-controlled, zero-humidity environment on thin water slabs. To probe the effect of surface wettability, we investigated the total time for room temperature water to completely freeze into ice on superhydrophilic ( θaapp→ 0°), hydrophilic (0° < θa < 90°), hydrophobic (90° < θa < 125°), and superhydrophobic ( θaapp→ 180°) surfaces. Our results show that at macroscopic length scales, heat conduction through the bulk water/ice layer dominates the freezing process when compared to heat conduction through the functional coatings or nanoscale gaps at the superhydrophobic substrate-water/ice interface. In order to verify our findings, and to determine when the surface structure thermal resistance approaches the water/ice resistance, we fabricated and tested the additional substrates coated with commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

  12. Europa's phase curve - Implications for surface structure

    NASA Technical Reports Server (NTRS)

    Domingue, D. L.; Hapke, B. W.; Lockwood, G. W.; Thompson, D. T.

    1991-01-01

    The surface of the Jovian satellite Europa is characterized on the basis of an analysis of ground photoelectric photometry at 470 and 550 nm and Voyager images. The data are presented in extensive tables and graphs and discussed in detail. At 550 nm, Europa has single-scattering albedo 0.964, opposition-effect amplitude 0.5, opposition-effect width 0.0016, double-lobed Henyey-Greenstein factors b = -0.429 and c = 0.113, and mean roughness angle 10 deg (much lower than on other solar-system objects). From the small roughness and the 96-percent porosity implied by the narrow opposition peak, it is concluded that the surface was formed mainly by endogenic processes. It is also noted that only one of three observational criteria for preferential ion bombardment of the trailing hemisphere are met in Europa.

  13. Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 13. Mineral Microscopy and Chemistry of Mined and Unmined Porphyry Molybdenum Mineralization Along the Red River, New Mexico: Implications for Ground- and Surface-Water Quality

    USGS Publications Warehouse

    Plumlee, Geoff; Lowers, Heather; Ludington, Steve; Koenig, Alan; Briggs, Paul

    2005-01-01

    This report is one in a series presenting results of an interdisciplinary U.S. Geological Survey (USGS) study of ground-water quality in the lower Red River watershed prior to open-pit and underground molybdenite mining at Molycorp's Questa mine. The stretch of the Red River watershed that extends from just upstream of the town of Red River to just above the town of Questa includes several mineralized areas in addition to the one mined by Molycorp. Natural erosion and weathering of pyrite-rich rocks in the mineralized areas has created a series of erosional scars along this stretch of the Red River that contribute acidic waters, as well as mineralized alluvial material and sediments, to the river. The overall goal of the USGS study is to infer the pre-mining ground-water quality at the Molycorp mine site. An integrated geologic, hydrologic, and geochemical model for ground water in the mineralized but unmined Straight Creek drainage is being used as an analogue for the geologic, geochemical, and hydrologic conditions that influenced ground-water quality and quantity at the mine site prior to mining. This report summarizes results of reconnaissance mineralogical and chemical characterization studies of rock samples collected from the various scars and the Molycorp open pit, and of drill cuttings or drill core from bedrock beneath the scars and adjacent debris fans.

  14. Radiolysis of water with aluminum oxide surfaces

    NASA Astrophysics Data System (ADS)

    Reiff, Sarah C.; LaVerne, Jay A.

    2017-02-01

    Aluminum oxide, Al2O3, nanoparticles with water were irradiated with γ-rays and 5 MeV He ions followed by the determination of the production of molecular hydrogen, H2, and characterization of changes in the particle surface. Surface analysis techniques included: diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), nitrogen absorption with the Brunauer - Emmett - Teller (BET) methodology for surface area determination, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Production of H2 by γ-ray radiolysis was determined for samples with adsorbed water and for Al2O3 - water slurries. For Al2O3 samples with adsorbed water, the radiation chemical yield of H2 was measured as 80±20 molecules/100 eV (1 molecule/100 eV=1.04×10-7 mol/J). The yield of H2 was observed to decrease as the amount of water present in the Al2O3 - water slurries increased. Surface studies indicated that the α-phase Al2O3 samples changed phase following irradiation by He ions, and that the oxyhydroxide layer, present on the pristine sample, is removed by γ-ray and He ion irradiation.

  15. Water vapor interactions with polycrystalline titanium surfaces

    NASA Astrophysics Data System (ADS)

    Azoulay, A.; Shamir, N.; Volterra, V.; Mintz, M. H.

    1999-02-01

    The initial interactions of water vapor with polycrystalline titanium surfaces were studied at room temperature. Measurements of water vapor surface accumulation were performed in a combined surface analysis system incorporating direct recoils spectrometry (DRS), Auger electron spectroscopy and X-ray photoelectron spectroscopy. The kinetics of accommodation of the water dissociation fragments (H, O and OH) displayed a complex behavior depending not only on the exposure dose but also on the exposure pressure. For a given exposure dose the efficiency of chemisorption increased with increasing exposure pressure. DRS measurements indicated the occurrence of clustered hydroxyl moieties with tilted O-H bonds formed even at very low surface coverage. A model which assumes two parallel routes of chemisorption, by direct collisions (Langmuir type) and by a precursor state is proposed to account for the observed behavior. The oxidation efficiency of water seemed to be much lower than that of oxygen. No Ti 4+ states were detected even at high water exposure values. It is likely that hydroxyl species play an important role in the reduced oxidation efficiency of water.

  16. Polarimetric thermal emission from periodic water surfaces

    NASA Technical Reports Server (NTRS)

    Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Wilson, W. J.; Li, F. K.; Johnson, J. T.; Kong, J. A.

    1993-01-01

    Experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. For our ground-based Ku-band radiometer measurements, a water pool was constructed on the roof of a building in the Jet Propulsion Laboratory, and a fiberglass surface with periodic corrugations in one direction was impressed on the top of the water surface to create a stationary water surface underneath it. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with the theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate the Stokes parameters of periodic surfaces without fiberglass surface layer and with rms height of the order of wind-generated water ripples. The magnitudes of the azimuthal variation of the calculated emissivities at horizontal and vertical polarizations corresponding to the first two Stokes parameters are found to be comparable to the values measured by airborne radiometers and SSM/I. In addition, the third Stokes parameter not shown in the literature is seen to have approximately twice the magnitude of the azimuth variation of either T(sub h) or T(sub v), which may make it more sensitive to the row direction, while less susceptive to noises because the atmospheric and system noises tend to be unpolarized and are expected to be cancelled out when the third Stokes parameter is derived as the difference of two or three power measurements, as indicated by another experiment carried out at a swimming pool with complicated surroundings. The results indicate that passive polarimetry is a potential technology in the remote sensing of ocean wind vector which is a crucial component in the understanding of global climate change. Issues related to the application of microwave passive polarimetry to ocean wind are also discussed.

  17. Polarimetric thermal emission from periodic water surfaces

    NASA Technical Reports Server (NTRS)

    Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Wilson, W. J.; Li, F. K.; Johnson, J. T.; Kong, J. A.

    1993-01-01

    Experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. For our ground-based Ku-band radiometer measurements, a water pool was constructed on the roof of a building in the Jet Propulsion Laboratory, and a fiberglass surface with periodic corrugations in one direction was impressed on the top of the water surface to create a stationary water surface underneath it. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with the theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate the Stokes parameters of periodic surfaces without fiberglass surface layer and with rms height of the order of wind-generated water ripples. The magnitudes of the azimuthal variation of the calculated emissivities at horizontal and vertical polarizations corresponding to the first two Stokes parameters are found to be comparable to the values measured by airborne radiometers and SSM/I. In addition, the third Stokes parameter not shown in the literature is seen to have approximately twice the magnitude of the azimuth variation of either T(sub h) or T(sub v), which may make it more sensitive to the row direction, while less susceptive to noises because the atmospheric and system noises tend to be unpolarized and are expected to be cancelled out when the third Stokes parameter is derived as the difference of two or three power measurements, as indicated by another experiment carried out at a swimming pool with complicated surroundings. The results indicate that passive polarimetry is a potential technology in the remote sensing of ocean wind vector which is a crucial component in the understanding of global climate change. Issues related to the application of microwave passive polarimetry to ocean wind are also discussed.

  18. Water surface locomotion in tropical canopy ants.

    PubMed

    Yanoviak, S P; Frederick, D N

    2014-06-15

    Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants. © 2014. Published by The Company of Biologists Ltd.

  19. Persistent Urban Influence on Surface Water Quality via Impacted Groundwater.

    PubMed

    Gabor, Rachel S; Hall, Steven J; Eiriksson, David P; Jameel, Yusuf; Millington, Mallory; Stout, Trinity; Barnes, Michelle L; Gelderloos, Andrew; Tennant, Hyrum; Bowen, Gabriel J; Neilson, Bethany T; Brooks, Paul D

    2017-09-05

    Growing urban environments stress hydrologic systems and impact downstream water quality. We examined a third-order catchment that transitions from an undisturbed mountain environment into urban Salt Lake City, Utah. We performed synoptic surveys during a range of seasonal baseflow conditions and utilized multiple lines of evidence to identify mechanisms by which urbanization impacts water quality. Surface water chemistry did not change appreciably until several kilometers into the urban environment, where concentrations of solutes such as chloride and nitrate increase quickly in a gaining reach. Groundwater springs discharging in this gaining system demonstrate the role of contaminated baseflow from an aquifer in driving stream chemistry. Hydrometric and hydrochemical observations were used to estimate that the aquifer contains approximately 18% water sourced from the urban area. The carbon and nitrogen dynamics indicated the urban aquifer also serves as a biogeochemical reactor. The evidence of surface water-groundwater exchange on a spatial scale of kilometers and time scale of months to years suggests a need to evolve the hydrologic model of anthropogenic impacts to urban water quality to include exchange with the subsurface. This has implications on the space and time scales of water quality mitigation efforts.

  20. A Water Rich Mars Surface Mission Scenario

    NASA Technical Reports Server (NTRS)

    Hoffman, Stephen; Andrews, Alida; Joosten, Kent; Watts, Kevin

    2017-01-01

    The surface of Mars once had abundant water flowing on its surface, but now there is a general perception that this surface is completely dry. Several lines of research have shown that there are sources of potentially large quantities of water at many locations on the surface, including regions considered as candidates for future human missions. Traditionally, system designs for these human missions are constrained to tightly recycle water and oxygen, and current resource utilization strategies involve ascent vehicle oxidizer production only. But the assumption of relatively abundant extant water may change this. Several scenarios were constructed to evaluate water requirements for human Mars expeditions to assess the impact to system design if locally produced water is available. Specifically, we have assessed water resources needed for 1) ascent vehicle oxidizer and fuel production, 2) open-loop water and oxygen life support requirements along with more robust usage scenarios, and 3) crew radiation protection augmentation. In this assessment, production techniques and the associated chemistry to transform Martian water and atmosphere into these useful commodities are identified, but production mass and power requirements are left to future analyses. The figure below illustrates the type of water need assessment performed and that will be discussed. There have been several sources of feedstock material discussed in recent literature that could be used to produce these quantities of water. This paper will focus on Mars surface features that resemble glacier-like forms on Earth. Several lines of evidence indicate that some of these features are in fact buried ice, likely remnants from an earlier ice age on Mars. This paper examines techniques and hardware systems used in the polar regions of Earth to access this buried ice and withdraw water from it. These techniques and systems will be described to illustrate options available. A technique known as a Rodriguez Well

  1. Surface hydrological cycle in Atlantic surface waters from stable isotopes

    NASA Astrophysics Data System (ADS)

    Benetti, Marion; Reverdin, Gilles; Aloisi, Giovanni; Erla Sveinbjörnsdóttir, Árný

    2017-04-01

    We explore the potential of seawater stable isotope data (δ18O and δD) to investigate the surface hydrological cycle in surface waters of the Atlantic Ocean and the Mediterranean Sea during the period 2010-2016. Our approach which combines these seawater observations with salinity and stable isotope measurements in the atmospheric water vapor, identifies large scale mixing processes between different water masses. Moreover, based on reasonable assumptions on seawater sources, as well as properties of evaporative and precipitating water, the δ-S distribution gives qualitative indications on the dominant contribution of evaporation (E) and meteoric water input (MW). To provide quantitative estimates of the E:MW ratio, we use the box model from Craig and Gordon (1965) which identifies the subtropical gyre as a region where E:MW 2 and the tropical ocean as a region were MW:E 2. Finally, we show that the δ18O-δD distribution is better represented by a linear fit than the δ-S relationship, even in basins governed by different hydrological processes. In the tropical region where MW exceeds E, the δ18O-δD distribution identifies the MW inputs from their kinetic signature, whereas in regions where E exceeds MW, the δ18O-δD distribution traces the humidity at the sea surface.

  2. Shale gas development impacts on surface water quality in Pennsylvania

    PubMed Central

    Olmstead, Sheila M.; Muehlenbachs, Lucija A.; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J.

    2013-01-01

    Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl−) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl− concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl− concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

  3. Shale gas development impacts on surface water quality in Pennsylvania.

    PubMed

    Olmstead, Sheila M; Muehlenbachs, Lucija A; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J

    2013-03-26

    Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl(-)) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl(-) concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl(-) concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases.

  4. Water dynamics near solutes and surfaces

    NASA Astrophysics Data System (ADS)

    Moilanen, David Emil

    The hydrogen bonding structure and dynamics of water are fundamentally important in a wide range of chemical, biological, geological, and industrial systems. Infrared spectroscopy of the OD stretch of dilute HOD in H2 O provides a sensitive probe of the hydrogen bonding network of water. Water forms a nominally tetrahedral hydrogen bonding network as a liquid but rapid hydrogen bond switching events lead to fast water reorientation. A mechanism for water reorientation that involves large amplitude angular jumps has recently been proposed to describe the long time orientational dynamics. At short times, water molecules quickly sample a restricted range of angular space within an intact hydrogen bonding configuration. The amplitude of this inertial reorientation depends on the strength of the local hydrogen bonding network. When hydrogen bonds are stronger, the water is restricted to a smaller angular range about the hydrogen bond axis. Weaker hydrogen bonds allow larger angular excursions. A simple model for the angular hydrogen bond potential energy surface is presented based on the experimental data. Water is rarely found as a pure liquid in real systems. Often it is in contact with a surface and its dynamics are modified near the surface. Reverse micelles formed using the surfactant Aerosol-OT (AOT), water, and isooctane, as well as AOT lamellar structures provide well-defined, tunable model systems to study the dynamics of water interacting with an interface. Reverse micelles are spherical water pools with radii that can be varied from less than one nanometer up to tens of nanometers. Lamellar structures are surfactant bilayers separated by thin sheets of water ranging in thickness from approximately one nanometer up to four nanometers. In large reverse micelles and lamellar structures, the confined water can be separated into two components, a core of bulk-like water and a shell of interfacial water. Polarization selective pump-probe spectroscopy of the OD

  5. Coupled surface-water and ground-water model

    USGS Publications Warehouse

    Swain, Eric D.; Wexler, Eliezer J.

    1991-01-01

    In areas with dynamic and hydraulically well connected ground-water and surface-water systems, it is desirable that stream-aquifer interaction be simulated with models of equal sophistication and accuracy. Accordingly, a new, coupled ground-water and surface-water model was developed by combining the U.S. Geological Survey models MODFLOW and BRANCH. MODFLOW is the widely used modular three-dimensional, finite-difference, ground-water model and BRANCH is a one-dimensional numerical model commonly used to simulate flow in open-channel networks. Because time steps used in ground-water modeling commonly are much longer than those used in surface-water simulations, provision has been made for handling multiple BRANCH time steps within one MODFLOW time step. Verification testing of the coupled model was done using data from previous studies and by comparing results with output from a simpler four-point implicit open-channel flow model linked with MODFLOW.

  6. Surface Modification of Water Purification Membranes.

    PubMed

    Miller, Daniel J; Dreyer, Daniel R; Bielawski, Christopher W; Paul, Donald R; Freeman, Benny D

    2017-04-18

    Polymeric membranes are an energy-efficient means of purifying water, but they suffer from fouling during filtration. Modification of the membrane surface is one route to mitigating membrane fouling, as it helps to maintain high levels of water productivity. Here, a series of common techniques for modification of the membrane surface are reviewed, including surface coating, grafting, and various treatment techniques such as chemical treatment, UV irradiation, and plasma treatment. Historical background on membrane development and surface modification is also provided. Finally, polydopamine, an emerging material that can be easily deposited onto a wide variety of substrates, is discussed within the context of membrane modification. A brief summary of the chemistry of polydopamine, particularly as it may pertain to membrane development, is also described.

  7. Surface-Water Conditions in Georgia, Water Year 2005

    USGS Publications Warehouse

    Painter, Jaime A.; Landers, Mark N.

    2007-01-01

    INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link

  8. Chemical quality of surface waters in Pennsylvania

    USGS Publications Warehouse

    Durfor, Charles N.; Anderson, Peter W.

    1963-01-01

    Pennsylvania has an abundant supply of surface water of good quality. The average rainfall over the 45,300 square miles in the State is about 42 inches per year. Of this amount, about 50 percent appears in the streams as runoff. The combined mean annual runoff of the Delaware, Ohio, and Susquehanna Rivers, at their farthest downstream measuring points in the State, is in excess of 81,000 cubic feet per second. Variations in the chemical quality of the surface waters in Pennsylvania are caused by areal differences in geology, urban and industrial development, mining, quarrying, land use, and runoff. Waters having the least dissolved solids are found in the glaciated northeastern and northwestern parts of the State; waters having higher values of hardness are found in the limestone terranes in the southeastern and south-central parts. In the anthracite coal fields in the northeast and in the bituminous coal fields in the southwest, many streams receive acid mine drainage, which lowers the alkalinity and increases the sulfate content of the waters. The chemical quality of surface waters in Pennsylvania is discussed in general terms. Introductory sections of the report cover the main causative factors which influence chemical quality.

  9. Ultra Water Repellent Polypropylene Surfaces with Tunable Water Adhesion.

    PubMed

    Zhu, Tang; Cai, Chao; Guo, Jing; Wang, Rong; Zhao, Ning; Xu, Jian

    2017-03-22

    Polypropylene (PP), including isotactic PP (i-PP) and atactic PP (a-PP) with distinct tacticity, is one of the most widely used general plastics. Herein, ultra water repellent PP coatings with tunable adhesion to water were prepared via a simple casting method. The pure i-PP coating shows a hierarchical morphology with micro/nanobinary structures, exhibiting a water contact angle (CA) larger than 150° and a sliding angle less than 5° (for 5 μL water droplet). In contrast, the pure a-PP coating has a less rough morphology with a water contact angle of about 130°, and the water droplets stick on the coating at any tilted angles. For the composite i-PP/a-PP coatings, however, ultra water repellency with CA > 150° but water adhesion tailorable from slippery to sticky can be realized, depending on the contents of a-PP and i-PP. The different wetting behaviors are due to the various microstructures of the composite coatings resulting from the distinct crystallization ability of a-PP and i-PP. Furthermore, the existence of a-PP in the composite coatings enhances the mechanical properties compared to the i-PP coating. The proposed method is feasible to modify various substrates and potential applications in no-loss liquid transportation, slippery surfaces, and patterned superhydrophobic surfaces are demonstrated.

  10. Pollution of surface water in Europe

    PubMed Central

    Key, A.

    1956-01-01

    This paper discusses pollution of surface water in 18 European countries. For each an account is given of its physical character, population, industries, and present condition of water supplies; the legal, administrative, and technical means of controlling pollution are then described, and an outline is given of current research on the difficulties peculiar to each country. A general discussion of various aspects common to the European problem of water pollution follows; standards of quality are suggested; some difficulties likely to arise in the near future are indicated, and international collaboration, primarily by the exchange of information, is recommended to check or forestall these trends. PMID:13374532

  11. Hydrologic implications of solid-water disposal

    USGS Publications Warehouse

    Schneider, William Joseph

    1970-01-01

    Site selection for disposal of solid wastes must be based on adequate water-resources information if pollutional potential is to be minimized. This will require regional as well as localized data on the water resources of the area. Only through such an approach can adequate protection be afforded to the environment in general and the water resources in particular.

  12. Surface-Water Data, Georgia, Water Year 1999

    USGS Publications Warehouse

    Alhadeff, S. Jack; Landers, Mark N.; McCallum, Brian E.

    1999-01-01

    Water resources data for the 1999 water year for Georgia consists of records of stage, discharge, and water quality of streams; and the stage and contents of lakes and reservoirs published in one volume in a digital format on a CD-ROM. This volume contains discharge records of 121 gaging stations; stage for 13 gaging stations; stage and contents for 18 lakes and reservoirs; continuous water quality records for 10 stations; and the annual peak stage and annual peak discharge for 75 crest-stage partial-record stations. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Georgia. Records of discharge and stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological water-supply papers entitled, 'Surface-Water Supply of the United States.' Through September 30, 1960, these water-supply papers were in an annual series and then in a 5-year series for 1961-65 and 1966-70. Records of chemical quality, water temperature, and suspended sediment were published from 1941 to 1970 in an annual series of water-supply papers entitled, 'Quality of Surface Waters of the United States.' Records of ground-water levels were published from 1935 to 1974 in a series of water-supply papers entitled, 'Ground-Water Levels in the United States.' Water-supply papers may be consulted in the libraries of the principal cities in the United States or may be purchased from the U.S. Geological Survey, Branch of Information Services, Federal Center, Box 25286, Denver, CO 80225. For water years 1961 through 1970, streamflow data were released by the U.S. Geological Survey in annual reports on a State-boundary basis prior to the two 5-year series water-supply papers, which cover this period. The data contained in the water-supply papers are considered the official record. Water-quality records for water years 1964 through 1970 were similarly released

  13. Global modelling of Cryptosporidium in surface water

    NASA Astrophysics Data System (ADS)

    Vermeulen, Lucie; Hofstra, Nynke

    2016-04-01

    Introduction Waterborne pathogens that cause diarrhoea, such as Cryptosporidium, pose a health risk all over the world. In many regions quantitative information on pathogens in surface water is unavailable. Our main objective is to model Cryptosporidium concentrations in surface waters worldwide. We present the GloWPa-Crypto model and use the model in a scenario analysis. A first exploration of global Cryptosporidium emissions to surface waters has been published by Hofstra et al. (2013). Further work has focused on modelling emissions of Cryptosporidium and Rotavirus to surface waters from human sources (Vermeulen et al 2015, Kiulia et al 2015). A global waterborne pathogen model can provide valuable insights by (1) providing quantitative information on pathogen levels in data-sparse regions, (2) identifying pathogen hotspots, (3) enabling future projections under global change scenarios and (4) supporting decision making. Material and Methods GloWPa-Crypto runs on a monthly time step and represents conditions for approximately the year 2010. The spatial resolution is a 0.5 x 0.5 degree latitude x longitude grid for the world. We use livestock maps (http://livestock.geo-wiki.org/) combined with literature estimates to calculate spatially explicit livestock Cryptosporidium emissions. For human Cryptosporidium emissions, we use UN population estimates, the WHO/UNICEF JMP sanitation country data and literature estimates of wastewater treatment. We combine our emissions model with a river routing model and data from the VIC hydrological model (http://vic.readthedocs.org/en/master/) to calculate concentrations in surface water. Cryptosporidium survival during transport depends on UV radiation and water temperature. We explore pathogen emissions and concentrations in 2050 with the new Shared Socio-economic Pathways (SSPs) 1 and 3. These scenarios describe plausible future trends in demographics, economic development and the degree of global integration. Results and

  14. Global modeling of fresh surface water temperature

    NASA Astrophysics Data System (ADS)

    Bierkens, M. F.; Eikelboom, T.; van Vliet, M. T.; Van Beek, L. P.

    2011-12-01

    Temperature determines a range of water physical properties, the solubility of oxygen and other gases and acts as a strong control on fresh water biogeochemistry, influencing chemical reaction rates, phytoplankton and zooplankton composition and the presence or absence of pathogens. Thus, in freshwater ecosystems the thermal regime affects the geographical distribution of aquatic species through their growth and metabolism, tolerance to parasites, diseases and pollution and life history. Compared to statistical approaches, physically-based models of surface water temperature have the advantage that they are robust in light of changes in flow regime, river morphology, radiation balance and upstream hydrology. Such models are therefore better suited for projecting the effects of global change on water temperature. Till now, physically-based models have only been applied to well-defined fresh water bodies of limited size (e.g., lakes or stream segments), where the numerous parameters can be measured or otherwise established, whereas attempts to model water temperature over larger scales has thus far been limited to regression type of models. Here, we present a first attempt to apply a physically-based model of global fresh surface water temperature. The model adds a surface water energy balance to river discharge modelled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by short and long-wave radiation and sensible and latent heat fluxes. Also included are ice-formation and its effect on heat storage and river hydraulics. We used the coupled surface water and energy balance model to simulate global fresh surface water temperature at daily time steps on a 0.5x0.5 degree grid for the period 1970-2000. Meteorological forcing was obtained from the CRU data set, downscaled to daily values with ECMWF

  15. NANOFILTRATION FOULANTS FROM A TREATED SURFACE WATER

    EPA Science Inventory

    The foulant from pilot nanofiltration membrane elements fed conventionally-treated surface water for 15 months was analyzed for organic, inorganic, and biological parameters. The foulant responsible for flux loss was shown to be a film layer 20 to 80 um thick with the greatest de...

  16. Total Nitrogen in Surface Water (Future)

    EPA Pesticide Factsheets

    Excess nitrogen in surface water can result in eutrophication. TOTALNFuture is reported in kilograms/hectare/year. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

  17. NANOFILTRATION FOULANTS FROM A TREATED SURFACE WATER

    EPA Science Inventory

    The foulant from pilot nanofiltration membrane elements fed conventionally-treated surface water for 15 months was analyzed for organic, inorganic, and biological parameters. The foulant responsible for flux loss was shown to be a film layer 20 to 80 um thick with the greatest de...

  18. Reduction of water surface tension significantly impacts gecko adhesion underwater.

    PubMed

    Stark, Alyssa Y; McClung, Brandon; Niewiarowski, Peter H; Dhinojwala, Ali

    2014-12-01

    The gecko adhesive system is dependent on weak van der Waals interactions that are multiplied across thousands of fine hair-like structures (setae) on geckos' toe pads. Due to the requirements of van der Waals forces, we expect that any interruption between the setae and substrate, such as a water layer, will compromise adhesion. Our recent results suggest, however, that the air layer (plastron) surrounding the superhydrophobic toe pads aid in expelling water at the contact interface and create strong shear adhesion in water when in contact with hydrophobic surfaces. To test the function of the air plastron, we reduced the surface tension of water using two surfactants, a charged anionic surfactant and a neutral nonionic surfactant. We tested geckos on three substrates: hydrophilic glass and two hydrophobic surfaces, glass with a octadecyl trichlorosilane self-assembled monolayer (OTS-SAM) and polytetrafluoroethylene (PTFE). We found that the anionic surfactant inhibited the formation of the air plastron layer and significantly reduced shear adhesion to all three substrates. Interestingly, the air plastron was more stable in the nonionic surfactant treatments than the anionic surfactant treatments and we found that geckos adhered better in the nonionic surfactant than in the anionic surfactant on OTS-SAM and PTFE but not on glass. Our results have implications for the evolution of a superhydrophobic toe pad and highlight some of the challenges faced in designing synthetic adhesives that mimic geckos' toes.

  19. Water at surfaces with tunable surface chemistries and the chiral imprint of water around DNA

    NASA Astrophysics Data System (ADS)

    Petersen, Poul

    Aqueous interfaces are ubiquitous in atmospheric chemistry and biological systems but are notoriously hard to probe experimentally. Surface-specific vibrational spectroscopy offers an avenue to directly probe the vibrational modes of the water OH stretching band but this method is challenging to implement to buried surfaces. Here we present results from sum-frequency generation (SFG) spectroscopy probing the buried interface between a functionalized surface and aqueous solutions. Studying such buried surfaces offers the advantage of being able to systematically tune the surface chemistry using self-assembled monolayers, i.e. the hydrophobic and hydrophilic character, and examine the effect on the interfacial water. In addition to water at these controlled surfaces, we have initiated studying water at biological surfaces. This includes the solvation structure around DNA. X-ray experiments at cryogenic temperatures have found crystallographic water in the minor grove of DNA giving rise to the notion of a spine of hydration surrounding DNA. Such structured water should exhibit a chiral structure adapted from DNA. We investigate if such a chiral water structure exist around DNA at room temperature using chiral SFG. This work was supported by the National Science Foundation under a NSF CAREER Grant (CHE-1151079).

  20. How water meets a hydrophobic surface: Reluctantly and with flucuations

    NASA Astrophysics Data System (ADS)

    Poynor Torigoe, Adele Nichole

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low density region forms near the surface. This depleted region would have implications in such diverse areas as colloidal self-assembly, and the boundary conditions of fluid flow. However, the literature still remains divided as to whether or not such a depleted region exists. To investigate the existence of this layer, we have employed three surface-sensitive techniques, time-resolved phase-modulated ellipsometry, surface plasmon resonance, and X-ray reflectivity. Both ellipsometry and X-ray reflectivity provide strong evidence for the low-density layer and illuminate unexpected temporal behavior. Using all three techniques, we found surprising fluctuations at the interface with a non-Gaussian distribution and a single characteristic time on the order of tenths of seconds. This information supports the idea that the boundary fluctuates with something akin to capillary waves. We have also investigated the dependence of the static and dynamic properties of the hydrophobic/water interface on variables such as temperature, contact angle, pH, dissolved gasses, and sample quality, among others, in a hope to discover the root of the controversy in the literature. We found that the depletion layer is highly dependent on temperature, contact angle and sample quality. This dependence might explain some of the discrepancies in the literature as different groups often use hydrophobic surfaces with different properties.

  1. Potential Implications of Approaches to Climate Change on the Clean Water Rule Definition of "Waters of the United States".

    PubMed

    Faust, Derek R; Moore, Matthew T; Emison, Gerald Andrews; Rush, Scott A

    2016-05-01

    The 1972 Clean Water Act was passed to protect chemical, physical, and biological integrity of United States' waters. The U.S. Environmental Protection Agency and U.S. Army Corps of Engineers codified a new "waters of the United States" rule on June 29, 2015, because several Supreme Court case decisions caused confusion with the existing rule. Climate change could affect this rule through connectivity between groundwater and surface waters; floodplain waters and the 100-year floodplain; changes in jurisdictional status; and sea level rise on coastal ecosystems. Four approaches are discussed for handling these implications: (1) "Wait and see"; (2) changes to the rule; (3) use guidance documents; (4) Congress statutorily defining "waters of the United States." The approach chosen should be legally defensible and achieved in a timely fashion to provide protection to "waters of the United States" in proactive consideration of scientifically documented effects of climate change on aquatic ecosystems.

  2. A Water Rich Mars Surface Mission Scenario

    NASA Technical Reports Server (NTRS)

    Hoffman, Stephen J.; Andrews, Alida; Joosten, B. Kent; Watts, Kevin

    2017-01-01

    In an on-going effort to make human Mars missions more affordable and sustainable, NASA continues to investigate the innovative leveraging of technological advances in conjunction with the use of accessible Martian resources directly applicable to these missions. One of the resources with the broadest utility for human missions is water. Many past studies of human Mars missions assumed a complete lack of water derivable from local sources. However, recent advances in our understanding of the Martian environment provides growing evidence that Mars may be more "water rich" than previously suspected. This is based on data indicating that substantial quantities of water are mixed with surface regolith, bound in minerals located at or near the surface, and buried in large glacier-like forms. This paper describes an assessment of what could be done in a "water rich" human Mars mission scenario. A description of what is meant by "water rich" in this context is provided, including a quantification of the water that would be used by crews in this scenario. The different types of potential feedstock that could be used to generate these quantities of water are described, drawing on the most recently available assessments of data being returned from Mars. This paper specifically focuses on sources that appear to be buried quantities of water ice. (An assessment of other potential feedstock materials is documented in another paper.) Technologies and processes currently used in terrestrial Polar Regions are reviewed. One process with a long history of use on Earth and with potential application on Mars - the Rodriguez Well - is described and results of an analysis simulating the performance of such a well on Mars are presented. These results indicate that a Rodriguez Well capable of producing the quantities of water identified for a "water rich" human mission are within the capabilities assumed to be available on the Martian surface, as envisioned in other comparable Evolvable

  3. [Microcystin-LR in surface water of Ponjavica River].

    PubMed

    Natić, Dejan; Jovanović, Dragana; Knezević, Tanja; Karadzić, Vesna; Bulat, Zorica; Matović, Vesna

    2012-09-01

    Cyanobacterial toxins befall a group of various compounds according to chemical structure and health effects on people and animals. The most significant in this large group of compounds are microcystins. Their presence in water used for human consumption causes serious health problems, liver beeing the target organ. Microcystins are spread all over the world. Waterblooms of cyanobacterias and their cyanotoxins are also common in the majority of surface waters in Serbia. The aim of this study was to propose HPLC method for determination of mikrocystin-LR, to validate the method and to use it for determination of microcystin-LR in the surface water of the river Ponjavica. The Ponjavica is very eutrophic water and has ideal conditions for the cyanobacterial growth. Sample of water form the Ponjavica river were collected during the summer 2008. Coupled columns (HLB, Sep-Pak), were used for sample preparation and HPLC/PDA method was used for quantification of microcystin-LR. Parameters of validation show that the proposed method is simple, fast, sensitive (0.1 mg/L) and selective with the yield of 89%-92%. The measuring uncertainty of +/- 5% was obtained. The obtained results for surface water show that microcystin concentration reached the maximum level during August and September (1.5 microg/L). The value is higher than maximum allowable concentration of microcystin in drinking water (1 microg/L) proposed by WHO. This study contributes to the issue of pollution of the National Park Ponjavica. Besides, literature data and WHO clearly point out harmfulness of cyanobasterias and their toxins and implicate the necessity of legislation concerning determination and monitoring of these toxins in our country. Method used for quentification of mycrocystin-LR was shown to be sensitive, selective, rapid and simple and could be recommended for routine determination of this toxin.

  4. Long Term 1 Enhanced Surface Water Treatment Rule Documents

    EPA Pesticide Factsheets

    The Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR) builds on the requirements of the Surface Water Treatment Rule and specifies treatment requirements to address Cryptosporidium m and other microbial contaminants in public water systems.

  5. Surface history of Mercury - Implications for terrestrial planets

    NASA Technical Reports Server (NTRS)

    Murray, B. C.; Strom, R. G.; Trask, N. J.; Gault, D. E.

    1975-01-01

    A plausible surface history of Mercury is presented which is suggested by Mariner 10 television pictures. Five periods are postulated which are delineated by successive variations in the modification of the surface by external and internal processes: accretion and differentiation, terminal heavy bombardment, formation of the Caloris basin, flooding of that basin and other areas, and light cratering accumulated on the smooth plains. Each period is described in detail; the overall history is compared with the surface histories of Venus, Mars, and the moon; and the implications of this history for earth are discussed. It is tentatively concluded that: Mercury is a differentiated planet most likely composed of a large iron core enclosed by a relatively thin silicate layer; heavy surface bombardment occurred about four billion years ago, which probably affected all the inner planets, and was followed by a period of volcanic activity; no surface modifications caused by tectonic, volcanic, or atmospheric processes took place after the volcanic period.

  6. Surface history of Mercury - Implications for terrestrial planets

    NASA Technical Reports Server (NTRS)

    Murray, B. C.; Strom, R. G.; Trask, N. J.; Gault, D. E.

    1975-01-01

    A plausible surface history of Mercury is presented which is suggested by Mariner 10 television pictures. Five periods are postulated which are delineated by successive variations in the modification of the surface by external and internal processes: accretion and differentiation, terminal heavy bombardment, formation of the Caloris basin, flooding of that basin and other areas, and light cratering accumulated on the smooth plains. Each period is described in detail; the overall history is compared with the surface histories of Venus, Mars, and the moon; and the implications of this history for earth are discussed. It is tentatively concluded that: Mercury is a differentiated planet most likely composed of a large iron core enclosed by a relatively thin silicate layer; heavy surface bombardment occurred about four billion years ago, which probably affected all the inner planets, and was followed by a period of volcanic activity; no surface modifications caused by tectonic, volcanic, or atmospheric processes took place after the volcanic period.

  7. Climate policy implications for agricultural water demand

    SciTech Connect

    Chaturvedi, Vaibhav; Hejazi, Mohamad I.; Edmonds, James A.; Clarke, Leon E.; Kyle, G. Page; Davies, Evan; Wise, Marshall A.; Calvin, Katherine V.

    2013-03-01

    Energy, water and land are scarce resources, critical to humans. Developments in each affect the availability and cost of the others, and consequently human prosperity. Measures to limit greenhouse gas concentrations will inevitably exact dramatic changes on energy and land systems and in turn alter the character, magnitude and geographic distribution of human claims on water resources. We employ the Global Change Assessment Model (GCAM), an integrated assessment model to explore the interactions of energy, land and water systems in the context of alternative policies to limit climate change to three alternative levels: 2.5 Wm-2 (445 ppm CO2-e), 3.5 Wm-2 (535 ppm CO2-e) and 4.5 Wm-2 (645 ppm CO2-e). We explore the effects of two alternative land-use emissions mitigation policy options—one which taxes terrestrial carbon emissions equally with fossil fuel and industrial emissions, and an alternative which only taxes fossil fuel and industrial emissions but places no penalty on land-use change emissions. We find that increasing populations and economic growth could be anticipated to almost triple demand for water for agricultural systems across the century even in the absence of climate policy. In general policies to mitigate climate change increase agricultural demands for water still further, though the largest changes occur in the second half of the century, under both policy regimes. The two policies examined profoundly affected both the sources and magnitudes of the increase in irrigation water demands. The largest increases in agricultural irrigation water demand occurred in scenarios where only fossil fuel emissions were priced (but not land-use change emission) and were primarily driven by rapid expansion in bioenergy production. In these scenarios water demands were large relative to present-day total available water, calling into question whether it would be physically possible to produce the associated biomass energy. We explored the potential of improved

  8. Streamers sliding on a water surface

    NASA Astrophysics Data System (ADS)

    Akishev, Yuri Semenov; Karalnik, Vladimir; Medvedev, Mikhail; Petryakov, Alexander; Trushkin, Nikolay; Shafikov, Airat

    2017-06-01

    The features of an electrical interaction between surface streamers (thin current filaments) sliding on a liquid and liquid itself are still unknown in many details. This paper presents the experimental results on properties of the surface streamers sliding on water with different conductivity (distilled and tap water). The streamers were initiated with a sharpened thin metallic needle placed above the liquid and stressed with a periodical or pulsed high voltage. Two electrode systems were used and tested. The first of them provides in advance the existence of the longitudinal electric field above the water. The second one imitates the electrode geometry of a pin-to-plane dielectric barrier discharge in which the barrier is a thick layer of liquid. The electrical and optical characteristics of streamers were complemented with data on the spectroscopic measurements. It was revealed that surface streamers on water have no spatial memory. Contribution to the topical issue "The 15th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XV)", edited by Nicolas Gherardi and Tomáš Hoder

  9. Uncertainty in surface water flood risk modelling

    NASA Astrophysics Data System (ADS)

    Butler, J. B.; Martin, D. N.; Roberts, E.; Domuah, R.

    2009-04-01

    Two thirds of the flooding that occurred in the UK during summer 2007 was as a result of surface water (otherwise known as ‘pluvial') rather than river or coastal flooding. In response, the Environment Agency and Interim Pitt Reviews have highlighted the need for surface water risk mapping and warning tools to identify, and prepare for, flooding induced by heavy rainfall events. This need is compounded by the likely increase in rainfall intensities due to climate change. The Association of British Insurers has called for the Environment Agency to commission nationwide flood risk maps showing the relative risk of flooding from all sources. At the wider European scale, the recently-published EC Directive on the assessment and management of flood risks will require Member States to evaluate, map and model flood risk from a variety of sources. As such, there is now a clear and immediate requirement for the development of techniques for assessing and managing surface water flood risk across large areas. This paper describes an approach for integrating rainfall, drainage network and high-resolution topographic data using Flowroute™, a high-resolution flood mapping and modelling platform, to produce deterministic surface water flood risk maps. Information is provided from UK case studies to enable assessment and validation of modelled results using historical flood information and insurance claims data. Flowroute was co-developed with flood scientists at Cambridge University specifically to simulate river dynamics and floodplain inundation in complex, congested urban areas in a highly computationally efficient manner. It utilises high-resolution topographic information to route flows around individual buildings so as to enable the prediction of flood depths, extents, durations and velocities. As such, the model forms an ideal platform for the development of surface water flood risk modelling and mapping capabilities. The 2-dimensional component of Flowroute employs

  10. Water use implications of biofuel scenarios

    NASA Astrophysics Data System (ADS)

    Teter, J.; Mishra, G. S.; Yeh, S.

    2012-12-01

    Existing studies rely upon attributional lifecycle analysis (LCA) approaches to estimate water intensity of biofuels in liters of irrigated/evapotranspiration water consumed for biofuel production. Such approaches can be misleading. From a policy perspective, a better approach is to compare differential water impacts among scenarios on a landscape scale. We address the shortcomings of existing studies by using consequential LCA, and incorporate direct and indirect land use (changes) of biofuel scenarios, marginal vs. average biofuel water use estimates, future climate, and geographic heterogeneity. We use the outputs of a partial equilibrium economic model, climate and soil data, and a process-based crop-soil-climate-water model to estimate differences in green water (GW - directly from precipitation to soil) and blue water (BW - supplied by irrigation) use among three scenarios: (1) business-as-usual (BAU), (2) Renewable Fuels Standard (RFS) mandates, and (3) a national Low Carbon Fuel Standard (LCFS) plus the RFS scenario. We use spatial statistical methods to interpolate key climatic variables using daily climate observations for the contiguous USA. Finally, we use FAO's crop model AquaCrop to estimate the domestic GW and BW impacts of biofuel policies from 2007-2035. We assess the differences among scenarios along the following metrics: (1) crop area expansion at the county level, including prime and marginal lands, (2) crop-specific and overall annual/seasonal water balances including (a) water inflows (irrigation & precipitation), (b) crop-atmosphere interactions: (evaporation & transpiration) and (d) soil-water flows (runoff & soil infiltration), in mm 3 /acre over the relevant time period. The functional unit of analysis is the BW and GW requirements of biofuels (mm3 per Btu biofuel) at the county level. Differential water use impacts among scenarios are a primarily a function of (1) land use conversion, in particular that of formerly uncropped land classes

  11. Water in Extrasolar Planets and Implications for Habitability

    NASA Astrophysics Data System (ADS)

    Noack, Lena; Snellen, Ignas; Rauer, Heike

    2017-09-01

    Exoplanet detection missions have found thousands of planets or planet candidates outside of the Solar System—some of which are in the habitable zone, where liquid water is possible at the surface. We give an overview of the recent progress in observations of water-rich exoplanets, detection of water in the atmosphere of gas giants and less-massive targets, and modelling of the interior and evolution of water layers in exoplanets. We summarise the possible habitability of water-rich planets and discuss the potential of future missions and telescopes towards the detection of water in the atmosphere of low-mass exoplanets or on their surface.

  12. Water droplet impact on elastic superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Weisensee, Patricia B.; Tian, Junjiao; Miljkovic, Nenad; King, William P.

    2016-07-01

    Water droplet impact on surfaces is a ubiquitous phenomenon in nature and industry, where the time of contact between droplet and surface influences the transfer of mass, momentum and energy. To manipulate and reduce the contact time of impacting droplets, previous publications report tailoring of surface microstructures that influence the droplet - surface interface. Here we show that surface elasticity also affects droplet impact, where a droplet impacting an elastic superhydrophobic surface can lead to a two-fold reduction in contact time compared to equivalent rigid surfaces. Using high speed imaging, we investigated the impact dynamics on elastic nanostructured superhydrophobic substrates having membrane and cantilever designs with stiffness 0.5-7630 N/m. Upon impact, the droplet excites the substrate to oscillate, while during liquid retraction, the substrate imparts vertical momentum back to the droplet with a springboard effect, causing early droplet lift-off with reduced contact time. Through detailed experimental and theoretical analysis, we show that this novel springboarding phenomenon is achieved for a specific range of Weber numbers (We >40) and droplet Froude numbers during spreading (Fr >1). The observation of the substrate elasticity-mediated droplet springboard effect provides new insight into droplet impact physics.

  13. Water droplet impact on elastic superhydrophobic surfaces

    PubMed Central

    Weisensee, Patricia B.; Tian, Junjiao; Miljkovic, Nenad; King, William P.

    2016-01-01

    Water droplet impact on surfaces is a ubiquitous phenomenon in nature and industry, where the time of contact between droplet and surface influences the transfer of mass, momentum and energy. To manipulate and reduce the contact time of impacting droplets, previous publications report tailoring of surface microstructures that influence the droplet - surface interface. Here we show that surface elasticity also affects droplet impact, where a droplet impacting an elastic superhydrophobic surface can lead to a two-fold reduction in contact time compared to equivalent rigid surfaces. Using high speed imaging, we investigated the impact dynamics on elastic nanostructured superhydrophobic substrates having membrane and cantilever designs with stiffness 0.5–7630 N/m. Upon impact, the droplet excites the substrate to oscillate, while during liquid retraction, the substrate imparts vertical momentum back to the droplet with a springboard effect, causing early droplet lift-off with reduced contact time. Through detailed experimental and theoretical analysis, we show that this novel springboarding phenomenon is achieved for a specific range of Weber numbers (We >40) and droplet Froude numbers during spreading (Fr >1). The observation of the substrate elasticity-mediated droplet springboard effect provides new insight into droplet impact physics. PMID:27461899

  14. Source Water Assessment for the Las Vegas Valley Surface Waters

    NASA Astrophysics Data System (ADS)

    Albuquerque, S. P.; Piechota, T. C.

    2003-12-01

    The 1996 amendment to the Safe Drinking Water Act of 1974 created the Source Water Assessment Program (SWAP) with an objective to evaluate potential sources of contamination to drinking water intakes. The development of a Source Water Assessment Plan for Las Vegas Valley surface water runoff into Lake Mead is important since it will guide future work on source water protection of the main source of water. The first step was the identification of the watershed boundary and source water protection area. Two protection zones were delineated. Zone A extends 500 ft around water bodies, and Zone B extends 3000 ft from the boundaries of Zone A. These Zones extend upstream to the limits of dry weather flows in the storm channels within the Las Vegas Valley. After the protection areas were identified, the potential sources of contamination in the protection area were inventoried. Field work was conducted to identify possible sources of contamination. A GIS coverage obtained from local data sources was used to identify the septic tank locations. Finally, the National Pollutant Discharge Elimination System (NPDES) Permits were obtained from the State of Nevada, and included in the inventory. After the inventory was completed, a level of risk was assigned to each potential contaminating activity (PCA). The contaminants of concern were grouped into five categories: volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), microbiological, and radionuclides. The vulnerability of the water intake to each of the PCAs was assigned based on these five categories, and also on three other factors: the physical barrier effectiveness, the risk potential, and the time of travel. The vulnerability analysis shows that the PCAs with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gas stations, auto repair shops, construction, and the wastewater treatment plant discharges. Based on the current water quality

  15. Water quality analysis of surface water: a Web approach.

    PubMed

    Prasad, Poonam; Chaurasia, Meenal; Sohony, R A; Gupta, Indrani; Kumar, R

    2013-07-01

    The chemical, physical and biological characteristics of water with respect to its suitability describe its quality. Concentration of pesticides or fertilisers degrades the water quality and affects marine life. A comprehensive environmental data information system helps to perform and complete common tasks in less time with less effort for data verification, data calculations, graph generation, and proper monitoring, which helps in the further mitigation step. In this paper, focus is given to a web-based system developed to express the quality of water in the imprecise environment of monitoring data. Water samples were analyzed for eight different surface water parameters, in which four parameters such as pH, dissolved oxygen, biochemical oxygen demand, and fecal coliform were used for the water quality index calculation following MPCB Water Quality Standards of class A-II for best designated use. The analysis showed that river points in a particular year were in very bad category with certainty level of 0-38% which is unsuitable for drinking purposes; samples in bad category had certainty level that ranged from 38 to 50%; samples in medium to good category had certainty levels from 50 to 100%, and the remaining samples were in good to excellent category, suitable for drinking purposes, with certainty levels from 63 to 100%.

  16. Atmospheric radiation model for water surfaces

    NASA Technical Reports Server (NTRS)

    Turner, R. E.; Gaskill, D. W.; Lierzer, J. R.

    1982-01-01

    An atmospheric correction model was extended to account for various atmospheric radiation components in remotely sensed data. Components such as the atmospheric path radiance which results from singly scattered sky radiation specularly reflected by the water surface are considered. A component which is referred to as the virtual Sun path radiance, i.e. the singly scattered path radiance which results from the solar radiation which is specularly reflected by the water surface is also considered. These atmospheric radiation components are coded into a computer program for the analysis of multispectral remote sensor data over the Great Lakes of the United States. The user must know certain parameters, such as the visibility or spectral optical thickness of the atmosphere and the geometry of the sensor with respect to the Sun and the target elements under investigation.

  17. Disconnected surface water and groundwater: from theory to practice.

    PubMed

    Brunner, Philip; Cook, Peter G; Simmons, Craig T

    2011-01-01

    When describing the hydraulic relationship between rivers and aquifers, the term disconnected is frequently misunderstood or used in an incorrect way. The problem is compounded by the fact that there is no definitive literature on the topic of disconnected surface water and groundwater. We aim at closing this gap and begin the discussion with a short introduction to the historical background of the terminology. Even though a conceptual illustration of a disconnected system was published by Meinzer (1923), it is only within the last few years that the underlying physics of the disconnection process has been described. The importance of disconnected systems, however, is not widely appreciated. Although rarely explicitly stated, many approaches for predicting the impacts of groundwater development on surface water resources assume full connection. Furthermore, management policies often suggest that surface water and groundwater should only be managed jointly if they are connected. However, although lowering the water table beneath a disconnected section of a river will not change the infiltration rate at that point, it can increase the length of stream that is disconnected. Because knowing the state of connection is of fundamental importance for sustainable water management, robust field methods that allow the identification of the state of connection are required. Currently, disconnection is identified by showing that the infiltration rate from a stream to an underlying aquifer is independent of the water table position or by identifying an unsaturated zone under the stream. More field studies are required to develop better methods for the identification of disconnection and to quantify the implications of heterogeneity and clogging processes in the streambed on disconnection.

  18. Water Protects Graphitic Surface from Airborne Hydrocarbon Contamination.

    PubMed

    Li, Zhiting; Kozbial, Andrew; Nioradze, Nikoloz; Parobek, David; Shenoy, Ganesh Jagadeesh; Salim, Muhammad; Amemiya, Shigeru; Li, Lei; Liu, Haitao

    2016-01-26

    The intrinsic wettability of graphitic materials, such as graphene and graphite, can be readily obscured by airborne hydrocarbon within 5-20 min of ambient air exposure. We report a convenient method to effectively preserve a freshly prepared graphitic surface simply through a water treatment technique. This approach significantly inhibits the hydrocarbon adsorption rate by a factor of ca. 20×, thus maintaining the intrinsic wetting behavior for many hours upon air exposure. Follow-up characterization shows that a nanometer-thick ice-like water forms on the graphitic surface, which remains stabilized at room temperature for at least 2-3 h and thus significantly decreases the adsorption of airborne hydrocarbon on the graphitic surface. This method has potential implications in minimizing hydrocarbon contamination during manufacturing, characterization, processing, and storage of graphene/graphite-based devices. As an example, we show that a water-treated graphite electrode maintains a high level of electrochemical activity in air for up to 1 day.

  19. Simulation of lakes and surface water heat exchangers for design of surface water heat pump systems

    NASA Astrophysics Data System (ADS)

    Conjeevaram Bashyam, Krishna

    Surface Water Heat Pump (SWHP) system utilize surface water bodies, such as ponds, lakes, rivers, and the sea, as heat sources and/or sinks. These systems may be open-loop, circulating water between the surface water body and a heat exchanger on dry land, or closed-loop, utilizing a submerged surface water heat exchanger (SWHE). Both types of SWHP systems have been widely used, but little in the way of design data, design procedures, or energy calculation procedures is available to aid engineers in the design and analysis of these systems. For either type of SWHP system, the ability to predict the evolution of lake temperature with time is an important aspect of needed design and energy analysis procedures. This thesis describes the development and validation of a lake model that is coupled with a surface water heat exchanger model to predict both the lake dynamics (temperature, stratification, ice/snow cover) and the heat transfer performance of different types of SWHE. This one-dimensional model utilizes a detailed surface heat balance model at the upper boundary, a sediment conduction heat transfer model at the lower boundary, and an eddy diffusion model to predict transport within the lake. The lake model is implemented as part of the developed software design tool, which can be used as an aid in the sizing of SWHE used in closed loop SWHP systems.

  20. Optical Triangulation on Instationary Water Surfaces

    NASA Astrophysics Data System (ADS)

    Mulsow, C.; Maas, H.-G.; Hentschel, B.

    2016-06-01

    The measurement of water surfaces is a key task in the field of experimental hydromechanics. Established techniques are usually gauge-based and often come with a large instrumental effort and a limited spatial resolution. The paper shows a photogrammetric alternative based on the well-known laser light sheet projection technique. While the original approach is limited to surfaces with diffuse reflection properties, the developed technique is capable of measuring dynamically on reflecting instationary surfaces. Contrary to the traditional way, the laser line is not observed on the object. Instead, using the properties of water, the laser light is reflected on to a set of staggered vertical planes. The resulting laser line is observed by a camera and measured by subpixel operators. A calibration based on known still water levels provides the parameters for the translation of image space measurements into water level and gradient determination in dynamic experiments. As a side-effect of the principle of measuring the reflected laser line rather than the projected one, the accuracy can be improved by almost a factor two. In experiments a standard deviation of 0.03 mm for water level changes could be achieved. The measuring rate corresponds to the frame rate of the camera. A complete measuring system is currently under development for the Federal Waterways Engineering and Research Institute (BAW). This article shows the basic principle, potential and limitations of the method. Furthermore, several system variants optimised for different requirements are presented. Besides the geometrical models of different levels of complexity, system calibration procedures are described too. The applicability of the techniques and their accuracy potential are shown in several practical tests.

  1. How Water Advances on Superhydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Schellenberger, Frank; Encinas, Noemí; Vollmer, Doris; Butt, Hans-Jürgen

    2016-03-01

    Superliquid repellency can be achieved by nano- and microstructuring surfaces in such a way that protrusions entrap air underneath the liquid. It is still not known how the three-phase contact line advances on such structured surfaces. In contrast to a smooth surface, where the contact line can advance continuously, on a superliquid-repellent surface, the contact line has to overcome an air gap between protrusions. Here, we apply laser scanning confocal microscopy to get the first microscopic videos of water drops advancing on a superhydrophobic array of micropillars. In contrast to common belief, the liquid surface gradually bends down until it touches the top face of the next micropillars. The apparent advancing contact angle is 180°. On the receding side, pinning to the top faces of the micropillars determines the apparent receding contact angle. Based on these observations, we propose that the apparent receding contact angle should be used for characterizing superliquid-repellent surfaces rather than the apparent advancing contact angle and hysteresis.

  2. Potential health implications of water resources depletion and sewage discharges in the Republic of Macedonia.

    PubMed

    Hristovski, Kiril D; Pacemska-Atanasova, Tatjana; Olson, Larry W; Markovski, Jasmina; Mitev, Trajce

    2016-08-01

    Potential health implications of deficient sanitation infrastructure and reduced surface water flows due to climate change are examined in the case study of the Republic of Macedonia. Changes in surface water flows and wastewater discharges over the period 1955-2013 were analyzed to assess potential future surface water contamination trends. Simple model predictions indicated a decline in surface water hydrology over the last half century, which caused the surface waters in Macedonia to be frequently dominated by >50% of untreated sewage discharges. The surface water quality deterioration is further supported by an increasing trend in modeled biochemical oxygen demand trends, which correspond well with the scarce and intermittent water quality data that are available. Facilitated by the climate change trends, the increasing number of severe weather events is already triggering flooding of the sewage-dominated rivers into urban and non-urban areas. If efforts to develop a comprehensive sewage collection and treatment infrastructure are not implemented, such events have the potential to increase public health risks and cause epidemics, as in the 2015 case of a tularemia outbreak.

  3. Field Techniques for Estimating Water Fluxes Between Surface Water and Ground Water

    USGS Publications Warehouse

    Rosenberry, Donald O.; LaBaugh, James W.

    2008-01-01

    This report focuses on measuring the flow of water across the interface between surface water and ground water, rather than the hydrogeological or geochemical processes that occur at or near this interface. The methods, however, that use hydrogeological and geochemical evidence to quantify water fluxes are described herein. This material is presented as a guide for those who have to examine the interaction of surface water and ground water. The intent here is that both the overview of the many available methods and the in-depth presentation of specific methods will enable the reader to choose those study approaches that will best meet the requirements of the environments and processes they are investigating, as well as to recognize the merits of using more than one approach. This report is designed to make the reader aware of the breadth of approaches available for the study of the exchange between surface and ground water. To accomplish this, the report is divided into four chapters. Chapter 1 describes many well-documented approaches for defining the flow between surface and ground waters. Subsequent chapters provide an in-depth presentation of particular methods. Chapter 2 focuses on three of the most commonly used methods to either calculate or directly measure flow of water between surface-water bodies and the ground-water domain: (1) measurement of water levels in well networks in combination with measurement of water level in nearby surface water to determine water-level gradients and flow; (2) use of portable piezometers (wells) or hydraulic potentiomanometers to measure hydraulic gradients; and (3) use of seepage meters to measure flow directly. Chapter 3 focuses on describing the techniques involved in conducting water-tracer tests using fluorescent dyes, a method commonly used in the hydrogeologic investigation and characterization of karst aquifers, and in the study of water fluxes in karst terranes. Chapter 4 focuses on heat as a tracer in hydrological

  4. Perfluorinated surfactants in surface and drinking waters.

    PubMed

    Skutlarek, Dirk; Exner, Martin; Färber, Harald

    2006-09-01

    In this paper recent results are provided of an investigation on the discovery of 12 perfluorinated surfactants (PS) in different surface and drinking waters (Skutlarek et al. 2006 a, Skutlarek et al. 2006 b). In the last years, many studies have reported ubiquitous distribution of this group of perfluorinated chemicals, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in the environment, particularly in wildlife animal and human samples (Giesy and Kannan 2001, Houde et al. 2006, Prevedouros et al. 2006). Perfluorinated surfactants (e.g. PFOS and PFOA) have shown different potentials for reproductory interference and carcinogenity in animal experiments as well as partly long half-lives in humans (Guruge et al. 2006, FSA UK 2006a, FSA UK 2006b, 3M 2005, OECD 2002, Yao and Zhong 2005). They possess compound-dependent extreme recalcitrance against microbiological and chemical degradation and, in addition, they show variable potentials for bioaccumulation in animals and humans (Houde et al. 2006). Surface and drinking water samples were collected from different sampling sites: Surface waters: samples taken from the rivers Rhine, Ruhr, Moehne and some of their tributaries. Further samples were taken from the Rhine-Herne-Canal and the Wesel-Datteln-Canal. Drinking waters: samples taken in public buildings of the Rhine-Ruhr area. After sample clean-up and concentration by solid-phase extraction, the perfluorinated surfactants were determined using HPLC-MS/MS. All measured concentrations (sum of seven mainly detected components) in the Rhine river and its main tributaries (mouths) were determined below 100 ng/L. The Ruhr river (tributary of the Rhine) showed the highest concentration (94 ng/L), but with a completely different pattern of components (PFOA as major component), as compared with the other tributaries and the Rhine river. Further investigations along the Ruhr river showed remarkably high concentrations of PS in the upper reaches of

  5. River regulation and interactions groundwater - surface water

    NASA Astrophysics Data System (ADS)

    Colleuille, H.; Wong, W. K.; Dimakis, P.; Pedersen, T. S.

    2003-04-01

    The determination of a minimum acceptable flow in a river affected by regulation is a major task in management of hydropower development. The Norwegian Water Resources and Energy Directorate (NVE), responsible for administrating the nation's water resources, requires an objective system that takes into account the needs of the developer and the rivers environment such as water quality, river biota, landscape, erosion and groundwater. A research project has been initiated with focus on interactions between groundwater and surface water. The purpose of the project is to provide the licensing authorities with tools for quantitative assessment of the effects of regulation on groundwater resources and at the same time the effect of groundwater abstraction on river flows. A small, urbanised alluvial plain (2 km^2) by the river Glomma in Central Southern Norway is used as a case study. The local aquifer consists of heterogeneous glaciofluvial and fluvial deposit, mainly sand and gravel. Two three-dimensional numerical models (Visual Modflow 3.0 and Feflow 5.0) have been used for this study. The models were calibrated with hydro-geological data collected in the field. Aquifer and river sediment has been examined by use of Ground Penetrating Radar (GPR) and soil samples collection. Preferential flow has been examined by tracer tests. Water level, temperature and electric conductivity have been recorded in both aquifer and river. Hydro-climatic regime has been analysed by statistical tools. The first task of the project is to carry out water balance studies in order to estimate the change in rate of groundwater recharge from and to the river along a normal hydrologic year with snowmelting, flood, and baseflow. The second task is to analyse the potential effect of change in the river water regime (due to regulation and consecutive clogging) on groundwater resources and their interaction with stream water.

  6. Convergent surface water distributions in U.S. cities

    Treesearch

    M.K. Steele; J.B. Heffernan; N. Bettez; J. Cavender-Bares; P.M. Groffman; J.M. Grove; S. Hall; S.E. Hobbie; K. Larson; J.L. Morse; C. Neill; K.C. Nelson; J. O' Neil-Dunne; L. Ogden; D.E. Pataki; C. Polsky; R. Roy Chowdhury

    2014-01-01

    Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and...

  7. Water erosion on mars and its biologic implications

    USGS Publications Warehouse

    Carr, M.H.

    1996-01-01

    The Martian surface shows abundant evidence of water erosion. Liquid water is unstable under present climatic conditions but conditions may have been different in the past. The planet has been volcanically active throughout its history. The combination of water and volcanism must have commonly resulted in hydrothermal environments similar to those in which grow the most primitive terrestrial life-forms.

  8. The radiation of surface wave energy: Implications for volcanic tremor

    NASA Astrophysics Data System (ADS)

    Haney, M. M.; Denolle, M.; Lyons, J. J.; Nakahara, H.

    2015-12-01

    The seismic energy radiated by active volcanism is one common measurement of eruption size. For example, the magnitudes of individual earthquakes in volcano-tectonic (VT) swarms can be summed and expressed in terms of cumulative magnitude, energy, or moment release. However, discrepancies exist in current practice when treating the radiated energy of volcano seismicity dominated by surface waves. This has implications for volcanic tremor, since eruption tremor typically originates at shallow depth and is made up of surface waves. In the absence of a method to compute surface wave energy, estimates of eruption energy partitioning between acoustic and seismic waves typically assume seismic energy is composed of body waves. Furthermore, without the proper treatment of surface wave energy, it is unclear how much volcanic tremor contributes to the overall seismic energy budget during volcanic unrest. To address this issue, we derive, from first principles, the expression of surface wave radiated energy. In contrast with body waves, the surface wave energy equation is naturally expressed in the frequency domain instead of the time domain. We validate our result by reproducing an analytical solution for the radiated power of a vertical force source acting on a free surface. We further show that the surface wave energy equation leads to an explicit relationship between energy and the imaginary part of the surface wave Green's tensor at the source location, a fundamental property recognized within the field of seismic interferometry. With the new surface wave energy equation, we make clear connections to reduced displacement and propose an improved formula for the calculation of surface wave reduced displacement involving integration over the frequency band of tremor. As an alternative to reduced displacement, we show that reduced particle velocity squared is also a valid physical measure of tremor size, one based on seismic energy rate instead of seismic moment rate. These

  9. Reactivity of Tc at the Groundwater-Surface Water Interface

    NASA Astrophysics Data System (ADS)

    Zachara, J. M.; Fredrickson, J.; McKinley, J.

    2014-12-01

    Technetium-99 (t1/2 =211,000y) is environmentally mobile as the pertechnetate oxyanion [99Tc(VII)O4-(aq)]. Tc(VII) may react to less soluble Tc(IV) at intermediate redox potentials (Eo = -0.36 V) through heterogeneous reduction with solid-phase biogenic reaction products. 99Tc is forecast to migrate through groundwater to the Columbia River at the U.S. DOE Hanford site in Washington State. Discharge to surface water will occur through a groundwater-surface water interaction zone with complex hydrogeology and biogeochemistry that is stimulated by the overlapping nutrient regimes of groundwater and surface water. The reactivity of pertechnetate in reduced sediments from this zone was investigated to determine effects of biogenic ferrous-Fe and sulfide-S on Tc(VII) reduction rate; and the resulting speciation, mineral association, and physical location of Tc(IV). 99Tc(VII) was reduced to near detection (<10-9 Mol/L) over periods of days to months. Tc(VII) reduction rate was first order in [Tc(VII)]aq and sediment mass, but correlations with specific biogenic reductant concentrations [(Fe(II), ferrous mono-sulfide] were not found. Tc(IV) was isolated to fine-grained aggregates (0.1 to 0.5 mm) of "mud", consisting of primary mineral material embedded within a phyllosilicate or clay matrix. EXAFS revealed that product Tc(IV) existed as combinations of a Tc(IV)O2-like phase ,Tc(IV)-Fe surface clusters, and/or TcSx. Ferrous mono-sulfide was implicated as a more selective reductant. Migration of Tc(VII) through the interaction zone will be controlled by water residence time and the density and spatial distribution of fine-grained aggregates that host reductive biogeochemical processes in otherwise coarse-textured, partially oxygenated sediments.

  10. [Prevalence of Aeromonas spp. in surface water].

    PubMed

    Hernández, P; Rodríguez de García, R

    1997-03-01

    Some Aeromonas strains are well recognized enteropathogens according to microbiological, clinical, immunological and epidemiological evidence. The main source of infection seems to be untreated water, these microorganisms can be found in virtually all aquatic environments. Additionally, some Aeromonas, which include enterotoxigenic strains, are capable of rapid growth at 5 degrees C and even of producing toxins. Vegetable products irrigated with contaminated water may reach critical Aeromonas levels after being kept under refrigeration, this could represent a public health risk when they are consumed as uncooked salads. This study was pursued to evaluate such risk. Surface water samples were streaked on starch ampicillin and inositol-brilliant green-bile salts agar dishes. In addition, 100 ml of each sample were filtered through a 0.45 micron Millipore membrane filter. The filters were incubated on alkaline peptone water as enrichment media during 24 h at 35 degrees C. Enrichment broth was then streaked on the selective agars above mentioned. Isolates from both tests were identified using the API 20 E System. The prevalence of Aeromonas strains in the analyzed samples was 17.8%. A higher isolation rate was observed after the enrichment technique. Starch ampicillin agar showed a higher recuperation rate. A Veronii biotype sobria (formerly A. sobria) was isolated with higher frequency. Since this species has been associated with the greatest virulence, the use of contaminated water to irrigate vegetable products that are to be kept under refrigeration and consumed without ulterior cooking may represent a risk to the public health.

  11. Surface drifters measuring sea water salinity

    NASA Astrophysics Data System (ADS)

    Reverdin, Gilles; Centurioni, Luca; Sena-Martins, Meike; Garcia-Ladona, Emilio; Ballabrera, Joaquim; Salvador, Joaquin; Sommer, Anna; Boutin, Jacqueline

    2017-04-01

    Surface drifters have been introduced in the early 1990s by P.P. Niiler to measure the salinity of the near-surface water as well as its temperature. First, they were deployed to document large scale advection of surface salinity fronts, such as during TOGA-COARE (1991). More recently, salinity drifter data were used for three purposes: 1 - provide in situ data coverage for validation of sea surface (SSS) products, such as provided by band-L microwave radiometry from satellite missions, Aquarius, SMOS, SMAP 2 - provide data for better understanding upper ocean response to air-sea interactions, such as during rainfall, or near-surface warming during low wind events 3 - provide estimates of surface advection of salinity features and their contribution to ocean freshwater budget We will review the drifters that have been deployed and where data were collected, the challenges encountered in correcting the data, ongoing plans and future developments. A comparison of salinity data of more than 60 SVP drifters to SMOS and Aquarius SSS fields in the North Atlantic subtropical gyre illustrates the potential for validating products from satellite missions over more than a year (SPURS-1 2012-2013 experiment). Data collocated during tropical rain events illustrate a short-term response of near-surface salinity and temperature that can be quantified, although we lack precise collocated wind data. It is rather consistent with independently-derived surface salinity response to rain based on SMOS salinity retrievals, and model estimations. An extreme case of close to 10 psu near-surface salinity drop due to rainfall is presented. Recent salinity drifter deployments in the rainy region of the eastern Pacific ITCZ (SPURS-2 2016 experiment) illustrate the small time and space scale variability associated with freshwater lenses in this region. Some data from a new tag (surpact) will be presented with simultaneous estimates of sea state, rain rate, temperature and salinity during rain

  12. Chemical composition of Texas surface waters, 1949

    USGS Publications Warehouse

    Irelan, Burdge

    1950-01-01

    This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium

  13. Acidic deposition and surface water chemistry

    NASA Astrophysics Data System (ADS)

    Church, M. R.

    A pair of back-to-back (morning and afternoon) hydrology sessions, held December 10, 1987, at the AGU Fall Meeting in San Francisco, Calif., covered “Predicting the Effects of Acidic Deposition on Surface Water Chemistry.” The combined sessions included four invited papers, 12 contributed papers, and a panel discussion at its conclusion. The gathering dealt with questions on a variety of aspects of modeling the effects of acidic deposition on surface water chemistry.Contributed papers included discussions on the representation of processes in models as well as limiting assumptions in model application (V. S. Tripathi et al., Oak Ridge National Laboratory, Oak Ridge, Tenn., and E. C. Krug, Illinois State Water Survey, Champaign), along with problems in estimating depositional inputs to catchments and thus inputs to be used in the simulation of catchment response (M. M. Reddy et al., U.S. Geological Survey, Lakewood, Colo.; and E. A. McBean, University of Waterloo, Waterloo, Canada). L. A. Baker et al. (University of Minnesota, Minneapolis) dealt with the problem of modeling seepage lake systems, an exceedingly important portion of the aquatic resources in Florida and parts of the upper U.S. Midwest. J. A. Hau and Y. Eckstein (Kent State University, Kent, Ohio) considered equilibrium modeling of two northern Ohio watersheds that receive very different loads of acidic deposition but are highly similar in other respects.

  14. Water droplet evaporation from sticky superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Lee, Moonchan; Kim, Wuseok; Lee, Sanghee; Baek, Seunghyeon; Yong, Kijung; Jeon, Sangmin

    2017-07-01

    The evaporation dynamics of water from sticky superhydrophobic surfaces was investigated using a quartz crystal microresonator and an optical microscope. Anodic aluminum oxide (AAO) layers with different pore sizes were directly fabricated onto quartz crystal substrates and hydrophobized via chemical modification. The resulting AAO layers exhibited hydrophobic or superhydrophobic characteristics with strong adhesion to water due to the presence of sealed air pockets inside the nanopores. After placing a water droplet on the AAO membranes, variations in the resonance frequency and Q-factor were measured throughout the evaporation process, which were related to changes in mass and viscous damping, respectively. It was found that droplet evaporation from a sticky superhydrophobic surface followed a constant contact radius (CCR) mode in the early stage of evaporation and a combination of CCR and constant contact angle modes without a Cassie-Wenzel transition in the final stage. Furthermore, AAO membranes with larger pore sizes exhibited longer evaporation times, which were attributed to evaporative cooling at the droplet interface.

  15. Experimental Study of Water Droplet Vaporization on Nanostructured Surfaces

    NASA Astrophysics Data System (ADS)

    Padilla, Jorge, Jr.

    -99. Heat transfer coefficients were determined from thermal measurements in the test apparatus. All experiments were conducted inside an ISO Class 5 clean room enclosure. It was observed that when a liquid water droplet impinged upon the ZnO nanostructured at surface temperatures less than 140 degrees C, the nominally spherical droplet spread into a thin film over the surface. The film thickness depended on many parameters but in general it measured approximately 100-400 micrometers. As a result, it was found that the droplet evaporated by film evaporation without initiating nucleate boiling. At wall superheat levels of 10-20 degrees C, it was found in some cases that the heat transfer coefficients were nearly 4 times greater than for those of nucleate boiling at the same superheat level. For these conditions, no bubble nucleation was observed visually, and, nevertheless, extremely high heat transfer coefficients resulting from rapid evaporation of the thin liquid film formed by the spreading droplet were observed. At high wall superheat levels, the vaporization process exhibited Leidenfrost droplet vaporization. The extreme wetting of the nanostructured surfaces resulted in high Leidenfrost transition temperatures in the range of 310-376 degrees C, among the highest in the literature, exceeding those exhibited by bare metal surfaces by 100 degrees C or more. The Leidenfrost transition was detected from a recording of the acoustic signal generated from each experiment during the deposition and subsequent evaporation process. It was defined as the first point for which there is no disturbance to the acoustical signal in the form of a sizzling sound beyond the initial violent popping generated during the droplet deposition. The results document a trend of increasing Leidenfrost temperature with decreasing contact angle, which is consistent with earlier studies. The results of this study are compared with earlier work in this area and the implications for applications are

  16. Water stress, water transfer and social equity in Northern China--implications for policy reforms.

    PubMed

    Cai, Ximing

    2008-04-01

    Water stress in Northern China is characterized with major, inefficient irrigation water use and rapidly growing non-agricultural water demands, as well as limited water quantity and declining water quality. Water use in the region is undergoing transfer from agricultural to municipal and industrial sectors. Currently, part of the economic loss and environmental damage due to water stress can be considered as a consequence of water transfer failures, including the current transfers, which hurt farmers' livelihood and income, and the needed transfers, which industry and cities have been waiting for but have not received. This paper starts with a discussion of the causes of water stress in Northern China, which is fundamental to understand the necessity and complexity of agricultural water transfers. Following that, it reviews water transfers in Northern China as a cause for concern over the social stability, economy and environment of the region. Based on an integrated analysis of economic, environmental, fiscal and social implications, this paper begins by identifying critical barriers to smooth water redistribution; and ends with implications for policy reforms, ensuring that farmers can and will save water. It is concluded that the decisions of water reallocation under water stress should be shared by communities at all levels, from the local to the national, to ensure equal access of water, especially the availability of the basic water need for all groups.

  17. Water evaporation on highly viscoelastic polymer surfaces.

    PubMed

    Pu, Gang; Severtson, Steven J

    2012-07-03

    Results are reported for a study on the evaporation of water droplets from a highly viscoelastic acrylic polymer surface. These are contrasted with those collected for the same measurements carried out on polydimethylsiloxane (PDMS). For PDMS, the evaporation process involves the expected multistep process including constant drop area, constant contact angle, and finally a combination of these steps until the liquid is gone. In contrast, water evaporation from the acrylic polymer shows a constant drop area mode throughout. Furthermore, during the evaporation process, the drop area actually expands on the acrylic polymer. The single mode evaporation process is consistent with formation of wetting structures, which cannot be propagated by the capillary forces. Expansion of the drop area is attributed to the influence of the drop capillary pressure. Furthermore, the rate of drop area expansion is shown to be dependent on the thickness of the polymer film.

  18. Water rotation barriers on protein molecular surfaces

    NASA Astrophysics Data System (ADS)

    Tompa, K.; Bokor, M.; Verebélyi, T.; Tompa, P.

    2015-02-01

    The experimental characterization of hindered-rotation barriers and mapping the energetic heterogeneity of water molecules bound to the molecular "surface" of proteins is critical for understanding the functional interaction of proteins with their environment. Here, we show how to achieve this goal by an original wide-line NMR procedure, which is based on the spectral motional narrowing phenomenon following the melting (thawing) process of interfacial ice. The procedure highlights the differences between globular and intrinsically disordered proteins and it enables to delineate the effect of solvent on protein structure, making a distinction between point mutants, monomeric and oligomeric states, and characterizing the molecular interactions taking part in different cellular processes. We put this unique experimental approach introducing novel physical quantities and quantifying the heterogeneous distribution of motional activation energy of water in the interfacial landscape into a historical perspective, demonstrating its utility through a variety of globular and disordered proteins.

  19. Surface Crystallization of Supercooled Water in Clouds

    NASA Technical Reports Server (NTRS)

    Tabazadeh, Azadeh; Gore, Warren J. (Technical Monitor)

    2002-01-01

    The process by which liquid cloud droplets homogeneously crystallize into ice is still not well-understood. The ice nucleation process based on the standard and classical theory of homogeneous freezing, initiates within the interior volume of a cloud droplet. Current experimental data on homogeneous freezing rates of ice in droplets of supercooled water, both in air and emulsion oil samples, show considerable scatter. For example, at -33 C, the reported volume-based freezing rates of ice in supercooled water vary by as much as 5 orders of magnitude, which is well outside the range of measurement uncertainties. Here, we show that the process of ice nucleus formation at the air (or oil)-liquid water interface may help to explain why experimental results on ice nucleation rates yield different results in different ambient phases. Our results also suggest that surface crystallization of ice in cloud droplets can explain why low amounts of supercooled water have been observed in the atmosphere near -40 C.

  20. Relaxations and Interfacial Water Ordering at the Corundum (110) Surface

    SciTech Connect

    Catalano, Jeffrey G.

    2010-09-17

    In situ high resolution specular X-ray reflectivity measurements were used to examine relaxations and interfacial water ordering occurring at the corundum (110)-water interface. Sample preparation affected the resulting surface structure. Annealing in air at 1373 K produced a reconstructed surface formed through an apparently ordered aluminum vacancy. The effect of the reconstruction on in-plane periodicity was not determined. The remaining aluminum sites on the surface maintain full coordination by oxygen and the surface was coated with a layer of physically adsorbed water. Ordering of water further from the surface was not observed. Acid etching of this surface and preparing a surface through annealing at 723 K both produced an unreconstructed surface with identical relaxations and water ordering. Relaxations were confined primarily to the top {approx}4 {angstrom} of the surface and were dominated by an increased distribution width of the fully occupied surface aluminum site and outward relaxation of the oxygen surface functional groups. A layer of adsorbed water fully coated the surface and occurred in two distinct sites. Water above this showed signs of layering and indicated that water ordering extended 7-10 {angstrom} from the surface. Relaxations and the arrangement of interfacial water were nearly identical on both the unreconstructed corundum and isostructural hematite (110) surfaces. Comparison to corundum and hematite (012) suggests that the arrangement of interfacial water is primarily controlled by mineral surface structure.

  1. Ground Water / Surface Water Exchange: Streambed Versus a Channel Bar

    NASA Astrophysics Data System (ADS)

    Shope, C. L.; Constantz, J. E.; Cooper, C. A.; McKay, W. A.

    2007-12-01

    The streambed is important in controlling exchange of water, solutes, and heat between streams and ground water. Processes such as sedimentation, erosion, and fluctuations in diurnal temperatures can have significant effects on the streambed hydraulic conductivity, which in turn affects fluid velocities across the streambed. The objectives of this study are to quantify the difference in flux magnitude and direction within and around a channel bar. The focus of this presentation is to compare fluxes in channel bar sediments with fluxes in the streambed to determine the effect of the upper boundary conditions on sediment fluxes. A network of piezometers was installed on and around a channel bar located within the Truckee River, a dense 6th order river network, located primarily in northwest Nevada. Instruments used were temperature loggers, pressure transducers, and stage recorders. Several methods were simultaneously utilized to quantify water and heat fluxes and to interpret the hydrodynamic processes through the streambed sediments. Numerical simulations are being completed to quantify the spatial and temporal fluid flux and heat transport in relation to varied hydraulic parameters such as variable river stage, geometry, and hydraulic conductivity. In general, we have found that surface water exchange to the streambed occurs at the upstream portion of bed features and streambed discharge dominates at the downstream bed feature. This exchange is evidenced at the channel bar as well as localized riffles and point bars adjacent to the channel bar. We found that at least two separate hydraulic conditions are evident during our study. The range in water levels between the piezometers was altered from approximately 1.25 m to a minimum of 0.10 m and the mean potentiometric surface increased by 1 m. These variations are geomorphic responses due to a flood event, inundating the channel bar, and a channel restoration project both upstream and downstream of the study area

  2. Implications of coccolithophores expanding to polar waters

    NASA Astrophysics Data System (ADS)

    Winter, A.; Henderiks, J.; Beaufort, L.

    2008-12-01

    There is much debate about the response of coccolithophores to decreased carbonate saturation state and decreased pH in the ocean as a result of increased CO2 partial pressure. It is still not known whether coccolithophores act as a sink or source for CO CO2. Nor is it known whether calcification will be reduced or increased in response to climate change. A proper understanding of the relationship between calcification and climate change is important not only because coccolithophores play an important role in determining the PIC:POC ratio of particle export into the deep ocean but also because climate change may affect the overall biodiversity of phytoplankton and the marine food chain. Because ocean acidification strongly affects polar regions, initially it seems unlikely that coccolithophores should prefer polar waters or even be a major component of phytoplankton in these regions. Yet there is much recent evidence that coccolithophores are increasingly expanding their range into polar oceans. This observation could be pivotal in improving our understanding of the mechanisms and rates of climatic adaptation by natural coccolithophore populations. We postulate that coccolithophores may be more sensitive to recent environmental changes, such as SSTs and salinity, than to factors more directly linked to changing ocean carbonate chemistry

  3. Chapter 5: Surface water quality sampling in streams and canals

    USDA-ARS?s Scientific Manuscript database

    Surface water sampling and water quality assessments have greatly evolved in the United States since the 1970s establishment of the Clean Water Act. Traditionally, water quality referred to only the chemical characteristics of the water and its toxicological properties related to drinking water or ...

  4. Water: one molecule, two surfaces, one mistake

    NASA Astrophysics Data System (ADS)

    Vega, Carlos

    2015-05-01

    In order to rigorously evaluate the energy and dipole moment of a certain configuration of molecules, one needs to solve the Schrödinger equation. Repeating this for many different configurations allows one to determine the potential energy surface (PES) and the dipole moment surface (DMS). Since the early days of computer simulation, it has been implicitly accepted that for empirical potentials the charges used to fit the PES should also be used to describe the DMS. This is a mistake. Partial charges are not observable magnitudes. They should be regarded as adjustable fitting parameters. Optimal values used to describe the PES are not necessarily the best to describe the DMS. One could use two fits: one for the PES and the other for the DMS. This is a common practice in the quantum chemistry community, but not used so often by the community performing computer simulations. This idea affects all types of modelling of water (with the exception of ab initio calculations) from coarse-grained to non-polarisable and polarisable models. We anticipate that an area that will benefit dramatically from having both, a good PES and a good DMS, is the modelling of water in the presence of electric fields.

  5. Asteroid surface materials - Mineralogical characterizations and cosmological implications

    NASA Technical Reports Server (NTRS)

    Gaffey, M. J.; Mccord, T. B.

    1977-01-01

    The theoretical basis for the interpretation of diagnostic spectral features is examined and previous characterizations of asteroid surface materials are considered. A summary is provided of results reported by Gaffey and McCord (1977) who have utilized the most sophisticated interpretive techniques available to interpret the spectral reflectance data of about 65 asteroids for mineralogic and petrologic information. Cosmological implications related to the study of asteroid surface materials are also considered, taking into account source bodies for the meteorites, postaccretionary thermal history, significant factors of asteroid thermal history, and the Apollo and Amor asteroids. It is found that the asteroids exhibit surface materials made up of assemblages of meteoritic minerals. The relative abundance of meteorite types reaching the earth's surface is very different from the population of mineralogic types on asteroid surfaces. The earth-crossing or -approaching asteroids apparently derive from a restricted source region or population which is very strongly depleted in the C2-like assemblages that dominate the belt as a whole.

  6. Surface-water quality-assurance plan for the USGS Georgia Water Science Center, 2010

    USGS Publications Warehouse

    Gotvald, Anthony J.

    2010-01-01

    The U.S. Geological Survey requires that each Water Science Center prepare a surface-water quality-assurance plan to describe policies and procedures that ensure high quality surface-water data collection, processing, analysis, computer storage, and publication. The Georgia Water Science Center's standards, policies, and procedures for activities related to the collection, processing, analysis, computer storage, and publication of surface-water data are documented in this Surface-Water Quality-Assurance Plan for 2010.

  7. Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

    NASA Technical Reports Server (NTRS)

    Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

    2011-01-01

    Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

  8. Landscape approach to identifying environments where ground water and surface water are closely interrelated

    USGS Publications Warehouse

    Winter, Thomas C.

    1995-01-01

    Understanding the interaction of ground water and surface water is fundamental to solving many of the water resource problems facing the Nation. To facilitate efficient management of the Nation's water resources, a program of study and evaluation of the interaction of ground water and surface water is proposed that would emphasize intersite comparison between 24 environments throughout the Nation.

  9. Organic acids in naturally colored surface waters

    USGS Publications Warehouse

    Lamar, William L.; Goerlitz, D.F.

    1966-01-01

    Most of the organic matter in naturally colored surface waters consists of a mixture of carboxylic acids or salts of these acids. Many of the acids color the water yellow to brown; however, not all of the acids are colored. These acids range from simple to complex, but predominantly they are nonvolatile polymeric carboxylic acids. The organic acids were recovered from the water by two techniques: continuous liquid-liquid extraction with n-butanol and vacuum evaporation at 50?C (centigrade). The isolated acids were studied by techniques of gas, paper, and column chromatography and infrared spectroscopy. About 10 percent of the acids recovered were volatile or could be made volatile for gas chromatographic analysis. Approximately 30 of these carboxylic acids were isolated, and 13 of them were individually identified. The predominant part of the total acids could not be made volatile for gas chromatographic analysis. Infrared examination of many column chromatographic fractions indicated that these nonvolatile substances are primarily polymeric hydroxy carboxylic acids having aromatic and olefinic unsaturation. The evidence suggests that some of these acids result from polymerization in aqueous solution. Elemental analysis of the sodium fusion products disclosed the absence of nitrogen, sulfur, and halogens.

  10. Irrigation efficiency and water-policy implications for river basin resilience

    NASA Astrophysics Data System (ADS)

    Scott, C. A.; Vicuña, S.; Blanco-Gutiérrez, I.; Meza, F.; Varela-Ortega, C.

    2014-04-01

    Rising demand for food, fiber, and biofuels drives expanding irrigation withdrawals from surface water and groundwater. Irrigation efficiency and water savings have become watchwords in response to climate-induced hydrological variability, increasing freshwater demand for other uses including ecosystem water needs, and low economic productivity of irrigation compared to most other uses. We identify three classes of unintended consequences, presented here as paradoxes. Ever-tighter cycling of water has been shown to increase resource use, an example of the efficiency paradox. In the absence of effective policy to constrain irrigated-area expansion using "saved water", efficiency can aggravate scarcity, deteriorate resource quality, and impair river basin resilience through loss of flexibility and redundancy. Water scarcity and salinity effects in the lower reaches of basins (symptomatic of the scale paradox) may partly be offset over the short-term through groundwater pumping or increasing surface water storage capacity. However, declining ecological flows and increasing salinity have important implications for riparian and estuarine ecosystems and for non-irrigation human uses of water including urban supply and energy generation, examples of the sectoral paradox. This paper briefly considers three regional contexts with broadly similar climatic and water-resource conditions - central Chile, southwestern US, and south-central Spain - where irrigation efficiency directly influences basin resilience. The comparison leads to more generic insights on water policy in relation to irrigation efficiency and emerging or overdue needs for environmental protection.

  11. Environmental implications of water efficient microcomponents in residential buildings.

    PubMed

    Fidar, A; Memon, F A; Butler, D

    2010-11-01

    The Code for Sustainable Homes (CSH) in England sets out various water efficiency targets/levels, which form part of environmental performance criteria against which the sustainability of a building is measured. The code is performance based and requires reduction in per capita water consumption in households. The water efficiency related targets can be met using a range of water efficient microcomponents (WC, showers, kitchen taps, basin taps, dishwashers, washing machines, and baths). However, while the CSH aims at reducing the adverse environmental implications associated with the dwellings by promoting reduction in water consumption, little is known about the energy consumption and the environmental impacts (e. g. carbon emissions) resulting from water efficient end uses. This paper describes a methodology to evaluate the energy consumption and carbon emissions associated with the CSH's water efficiency levels. Key findings are that some 96% and 87% of energy use and carbon emissions, respectively associated with urban water provision are attributable to in-house consumption (principally related to hot water), and that achieving a defined water efficiency target does not automatically save energy or reduce carbon emissions.

  12. Water Resources Data, Florida, Water Year 2001, Volume 3A. Southwest Florida Surface Water

    USGS Publications Warehouse

    Stoker, Y.E.; Kane, R.L.; Fletcher, W.L.

    2002-01-01

    Water resources data for the 2001 water year in Florida consist of continuous or daily discharges for 406 streams, periodic discharge for 12 streams, continuous daily stage for 142 streams, periodic stage for 12 streams, peak stage and discharge for 37 streams, continuous or daily elevations for 11 lakes, periodic elevations for 30 lakes; continuous ground-water levels for 424 wells, periodic ground-water levels for 1,426 wells, and quality-of-water data for 80 surface-water sites and 245 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 83 streams, periodic discharge for 10 streams, continuous or daily stage for 43 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 37 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  13. Water Resources Data, Florida, Water Year 2002, Volume 3A. Southwest Florida Surface Water

    USGS Publications Warehouse

    Kane, R.L.; Fletcher, W.L.

    2003-01-01

    Water resources data for the 2002 water year in Florida consist of continuous or daily discharges for 392 streams, periodic discharge for 15 streams, continuous daily stage for 191 streams, periodic stage for 13 streams, peak stage for 33 streams and peak discharge for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes; continuous ground-water levels for 418 wells, periodic ground-water levels for 1,287 wells, and quality-of-water data for 116 surface-water sites and 291 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 99 streams, periodic discharge for 11 streams, continuous or daily stage for 63 streams, peak stage and discharge for 7 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 59 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  14. Water Resources Data, Florida, Water Year 2003, Volume 3A: Southwest Florida Surface Water

    USGS Publications Warehouse

    Kane, R.L.; Fletcher, W.L.

    2004-01-01

    Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 103 streams, periodic discharge for 7 streams, continuous or daily stage for 67 streams, periodic stage for 13 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 62 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  15. Water resources data, Florida, water year 2004, volume 3A: southwest Florida surface water

    USGS Publications Warehouse

    Kane, Richard L.

    2004-01-01

    Water resources data for the 2004 water year in Florida consist of continuous or daily discharges for 405 streams, periodic discharge for 12 streams, continuous daily stage for 159 streams, periodic stage for 19 streams, peak stage for 30 streams and peak discharge for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 408 wells, periodic ground-water levels for 1,188 wells, and quality-of-water data for 140 surface-water sites and 240 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 104 streams, periodic discharge for 6 streams, continuous or daily stage for 36 streams, periodic stage for 14 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 3 lakes, and quality-of-water data for 58 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  16. Water resources data, Florida, water year 2005. Volume 3A: Southwest Florida surface water

    USGS Publications Warehouse

    Kane, Richard L.; Dickman, Mark

    2005-01-01

    Water resources data for the 2005 water year in Florida consist of continuous or daily discharges for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 streams, peak stage for 28 streams and peak discharge for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, and quality-of-water data for 211 surface-water sites and 208 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains records for continuous or daily discharge for 113 streams, periodic discharge for 4 streams, continuous or daily stage for 80 streams, periodic stage for 2 stream, peak stage and discharge for 8 streams, continuous or daily elevations for 3 lakes, continous or daily elevations for 3 lakes, and quality of water for 75 surface water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

  17. Bubble bouncing at a clean water surface.

    PubMed

    Zawala, Jan; Dorbolo, Stéphane; Vandewalle, Nicolas; Malysa, Kazimierz

    2013-10-28

    Experiments on the coalescence time of submillimeter bubbles colliding with a distilled water/air interface either being at rest (undisturbed) or vibrating vertically (with controlled amplitude and frequency) were carried out. It was found that the outcome of the bubble collision (coalescence or bounce) depends on impact velocity and size of the bubble, i.e. the parameters determining the bubble deformation degree. With the surface at rest, when the deformation of the bubble was sufficiently high, bubble bouncing was observed. It was caused by the fact that the radius of the intervening liquid film formed between the colliding bubble and water/air interface was large enough to prevent the liquid layer from reaching its thickness of rupture within the time of bubble-interface contact. Coalescence occurred in a consecutive collision if the bubble deformation was below a threshold value, as a result of dissipation of the kinetic energy associated with the bubble motion. The hypothesis about the crucial role of the bubble deformation and size of the liquid film formed in the bouncing mechanism was confirmed in a series of experiments where the bubble collided with a vibrating water/air interface. It was shown that when the kinetic energy was properly re-supplied from an external source (interface vibrations), the spectacular phenomenon of "immortal" bubbles, dancing indefinitely at the water/air interface, was achieved. It was shown that "immortal" bubble formation is a consequence of a similarly high degree of the bubble shape deformation and consequently a large enough radius of the liquid film formed.

  18. SO2:H2O surface complex found at the vapor/water interface.

    PubMed

    Tarbuck, Teresa L; Richmond, Geraldine L

    2005-12-07

    A weakly bonded SO2:H2O surface complex is found at the vapor/water interface prior to the reaction and dissolution of SO2 into the aqueous phase. The results have important implications for understanding the formation of atmospheric aerosols and understanding the atmospheric sulfur cycle.

  19. Structured free-water clusters near lubricating surfaces are essential in water-based lubrication.

    PubMed

    Hou, Jiapeng; Veeregowda, Deepak H; de Vries, Joop; Van der Mei, Henny C; Busscher, Henk J

    2016-10-01

    Water-based lubrication provides cheap and environmentally friendly lubrication and, although hydrophilic surfaces are preferred in water-based lubrication, often lubricating surfaces do not retain water molecules during shear. We show here that hydrophilic (42° water contact angle) quartz surfaces facilitate water-based lubrication to the same extent as more hydrophobic Si crystal surfaces (61°), while lubrication by hydrophilic Ge crystal surfaces (44°) is best. Thus surface hydrophilicity is not sufficient for water-based lubrication. Surface-thermodynamic analyses demonstrated that all surfaces, regardless of their water-based lubrication, were predominantly electron donating, implying water binding with their hydrogen groups. X-ray photoelectron spectroscopy showed that Ge crystal surfaces providing optimal lubrication consisted of a mixture of -O and =O functionalities, while Si crystal and quartz surfaces solely possessed -O functionalities. Comparison of infrared absorption bands of the crystals in water indicated fewer bound-water layers on hydrophilic Ge than on hydrophobic Si crystal surfaces, while absorption bands for free water on the Ge crystal surface indicated a much more pronounced presence of structured, free-water clusters near the Ge crystal than near Si crystal surfaces. Accordingly, we conclude that the presence of structured, free-water clusters is essential for water-based lubrication. The prevalence of structured water clusters can be regulated by adjusting the ratio between surface electron-donating and electron-accepting groups and between -O and =O functionalities.

  20. Possible surface reactions on Mars - Implications for Viking biology results

    NASA Technical Reports Server (NTRS)

    Ponnamperuma, C.; Shimoyama, A.; Yamada, M.; Hobo, T.; Pal, R.

    1977-01-01

    The results of two of the three biology experiments carried out on the Viking Mars landers have been simulated. The mixture of organic compounds labeled with carbon-14 used on Mars released carbon dioxide containing carbon-14 when reacted with a simulated Martian surface and atmosphere exposed to ultraviolet light (labeled release experiment). Oxygen was released when metal peroxides or superoxides were treated with water (gas exchange experiment). The simulations suggest that the results of these two Viking experiments can be explained on the basis of reactions of the Martian surface and atmosphere.

  1. Surface water quality-assurance plan, U.S. Geological Survey, Kentucky Water Science Center, water year 2006

    USGS Publications Warehouse

    Griffin, Michael S.

    2006-01-01

    This Surface Water Quality-Assurance Plan documents the standards, policies, and procedures used by the Kentucky Water Science Center for activities related to the collection, processing, storage, analysis, and publication of surface-water data.

  2. Metolachlor and atrazine fate in surface water systems

    SciTech Connect

    Rice, P.J.; Anderson, T.A.; Coats, J.R.

    1995-12-31

    The detection of pesticides in surface water and ground water provokes concern involving human health risks associated with pesticide exposure. Monitoring studies of surface waters have detected concentrations of herbicides that exceed the U.S. Environmental Protection Agency proposed maximum contamination level (MCL) for drinking water. Conventional water treatment processes do not remove many herbicides. Tap water drawn from surface-water sources has been reported to contain levels of herbicides above the regulatory limits. There is current interest in the use of artificial wetlands and macrophyte-cultured ponds in waste-water-treatment systems. Aquatic plant-based water treatment systems improve waste water effluent by solid filtration and nutrient assimilation. Various aquatic plants have been shown to accumulate metals, absorb inorganic ions, and accelerate the biodegradation of complex organics. Our research evaluates the fate of metolachlor and atrazine in surface water, surface water/sediment, and surface water/aquatic plant incubation systems to study the influence of sediment and aquatic plants in the removal and biotransformation of herbicides from contaminated waters. Aquatic macrophyte systems may prove to be useful in the remediation of herbicide contaminated surface waters in water treatment facilities or in the reduction of herbicide concentrations from tile drain effluents prior to entering watersheds.

  3. Comparison of fipronil sources in North Carolina surface water ...

    EPA Pesticide Factsheets

    Fipronil is a phenylpyrazole insecticide that is widely used in residential and agricultural settings to control ants, roaches, termites, and other pests. Fipronil and its transformation products have been found in a variety of environmental matrices, but the source[s] which makes the greatest contribution to fipronil in surface water has yet to be determined. A sampling effort designed to prioritize known fipronil inputs (golf courses, residential areas, biosolids application sites and wastewater facilities) was conducted in North Carolina to learn more about the origins of fipronil in surface water. High resolution mass spectrometry (HRMS) analysis indicated that fipronil and its known derivatives were routinely present in all samples, but concentrations were substantially elevated near wastewater treatment plant outfalls (range 10–500 ng/L combined), suggesting that they predominate as environmental sources. Corresponding recycled wastewater samples, which were treated with NaOCl for disinfection, showed disappearance of fipronil and all known degradates. HRMS and nuclear magnetic resonance (NMR) analysis techniques were used to determine that all fipronil-related compounds are oxidized to a previously unidentified fipronil sulfone chloramine species in recycled wastewater. The implications of the presence of a new fipronil-related compound in recycled wastewater need to be considered. Journal Article Highlights • The most important sources of fipronil in

  4. Surface-water availability, Tuscaloosa County, Alabama

    USGS Publications Warehouse

    Knight, Alfred L.; Davis, Marvin E.

    1975-01-01

    The average annual runoff, about 1,270 mgd (million gallons per day), originating in Tuscaloosa County is equivalent to 20 inches or 0.95 mgd per square mile. The Black Warrior and Sipsey Rivers, the largest streams in the county, have average flows of 5,230 mgd and 580 mgd, respectively, where they leave the county, and median annual 7-day low flows in excess of 150 mgd and 35 mgd, respectively. North River, Big Sandy Creek, and Hurricane Creek have average flows in excess of 100 mgd and median annual 7-day low flows in excess of 2 mgd. Surface water generally contains less than 100 mg/l (milligrams per liter) dissolved solids, less than 10 mg/l chloride, and is soft to moderately hard. Streams having the higher hardness and the higher dissolved-solids content are in eastern Tuscaloosa County.

  5. Constraints on surface evapotranspiration: implications for modeling and observations

    NASA Astrophysics Data System (ADS)

    Gentine, P.

    2015-12-01

    The continental hydrological cycle and especially evapotranspiration are constrained by additional factors such as the energy availability and the carbon cycle. As a results trying to understand and predict the surface hydrologic cycle in isolation might be highly unreliable. We present two examples were constraints induced by 1) radiation control through cloud albedo feedback and 2) carbon control on the surface water use efficiency are essential to correctly predict the seasonal hydrologic cycle. In the first example we show that correctly modeling diurnal and seasonal convection and the associated cloud-albedo feedback (through land-atmosphere and convection-large-scale circulation feedbacks) is essential to correctly model the surface hydrologic cycle in the Amazon, and to correct biases observed in all general circulation models. This calls for improved modeling of convection to correctly predict the tropical continental hydrologic cycle.In the second example we show that typical drought index based only on energy want water availability misses vegetation physiological and carbon feedback and cannot correctly represent the seasonal cycle of soil moisture stress. The typical Palmer Drought Stress Index is shown to be incapable of rejecting water stress in the future. This calls for new drought assessment metrics that may include vegetation and carbon feedback.

  6. Grooved organogel surfaces towards anisotropic sliding of water droplets.

    PubMed

    Zhang, Pengchao; Liu, Hongliang; Meng, Jingxin; Yang, Gao; Liu, Xueli; Wang, Shutao; Jiang, Lei

    2014-05-21

    Periodic micro-grooved organogel surfaces can easily realize the anisotropic sliding of water droplets attributing to the formed slippery water/oil/solid interface. Different from the existing anisotropic surfaces, this novel surface provides a versatile candidate for the anisotropic sliding of water droplets and might present a promising way for the easy manipulation of liquid droplets for water collection, liquid-directional transportation, and microfluidics.

  7. Water Sources of Temperate Upland Swamps of Eastern Australia. Implications for Groundwater Management and Climate Change.

    NASA Astrophysics Data System (ADS)

    Cowley, K.; Fryirs, K.; Chisari, R.; Hose, G. C.

    2016-12-01

    Temperate upland swamps in Eastern Australia are endangered ecological communities under State and National legislation. They occur in headwaters of low order streams on low relief plateaus, providing base flow to streams that contribute to Sydney's major drinking water supplies that support some 4.5 million people. The swamps are also subject to aquifer interference activities from long wall mining and groundwater extraction, and are threatened by a changing climate. It is therefore critical that we understand their water source, storage capacity and residence times. We collected seasonal water samples from perched swamp aquifers in two highland regions of Eastern Australia for analysis of hydrogen and oxygen isotopes and compared them with rainwater, surface water and deeper groundwater to determine whether the swamps were primarily rainwater or groundwater fed. 222Rn was used as an environmental tracer to calculate residence times and relative groundwater/surface water ratios. We found over 60% of the swamps were sensitive to evaporation which has implications for swamp health in a warmer climate. Over a third of water from the perched swamp aquifer is derived from deeper sandstone aquifers with residence times of between 1.2 and 15 days. This swamp-groundwater connectivity means that mining activities or large-scale groundwater extraction could interfere with a significant component of the swamps' water source, its water storage capacity and downstream contributions to Sydney's drinking water supplies.

  8. Mars water discoveries - implications for finding ancient and current life

    NASA Astrophysics Data System (ADS)

    Nelson, Mark

    2015-11-01

    There is some wonderful synchronicity right now for those interested in the search for water and life on Mars. Foremost is the recent announcement by NASA and the publication of a study using spectral imaging which definitively proves that there is seasonal, flowing briny water at a number of locations on Mars (see Fig. 1) (Ojha et al., 2015). This caps some 15 years of accumulating evidence that what was previously considered impossible is actually occurring on the Red Planet. "Water is essential to life as we know it," write Lujendra Ojha, Mary Beth Wilhelm, and their co-authors. "The presence of liquid water on Mars today has astrobiological, geologic, and hydrologic implications and may affect future human exploration".

  9. Mars water discoveries - implications for finding ancient and current life

    NASA Astrophysics Data System (ADS)

    Nelson, Mark

    2015-11-01

    There is some wonderful synchronicity right now for those interested in the search for water and life on Mars. Foremost is the recent announcement by NASA and the publication of a study using spectral imaging which definitively proves that there is seasonal, flowing briny water at a number of locations on Mars (see Fig. 1) (Ojha et al., 2015). This caps some 15 years of accumulating evidence that what was previously considered impossible is actually occurring on the Red Planet. ;Water is essential to life as we know it,; write Lujendra Ojha, Mary Beth Wilhelm, and their co-authors. ;The presence of liquid water on Mars today has astrobiological, geologic, and hydrologic implications and may affect future human exploration;.

  10. Lidar point density analysis: implications for identifying water bodies

    USGS Publications Warehouse

    Worstell, Bruce B.; Poppenga, Sandra; Evans, Gayla A.; Prince, Sandra

    2014-01-01

    Most airborne topographic light detection and ranging (lidar) systems operate within the near-infrared spectrum. Laser pulses from these systems frequently are absorbed by water and therefore do not generate reflected returns on water bodies in the resulting void regions within the lidar point cloud. Thus, an analysis of lidar voids has implications for identifying water bodies. Data analysis techniques to detect reduced lidar return densities were evaluated for test sites in Blackhawk County, Iowa, and Beltrami County, Minnesota, to delineate contiguous areas that have few or no lidar returns. Results from this study indicated a 5-meter radius moving window with fewer than 23 returns (28 percent of the moving window) was sufficient for delineating void regions. Techniques to provide elevation values for void regions to flatten water features and to force channel flow in the downstream direction also are presented.

  11. Chemical interactions between the present-day Martian atmosphere and surface minerals: Implications for sample return

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald; Fegley, Bruce

    1988-01-01

    Thermochemical and photochemical reactions between surface minerals and present-day atmospheric constituents are predicted to produce microscopic effects on the surface of mineral grains. Relevant reactions hypothesized in the literature include conversions of silicates and volcanic glasses to clay minerals, conversion of ferrous to ferric compounds, and formation of carbonates, nitrates, and sulfates. These types of surface-atmosphere weathering of minerals, biological potential of the surface environment, and atmospheric stability in both present and past Martian epochs. It is emphasized that the product of these reactions will be observable and interpretable on the microscopic surface layers of Martian surface rocks using modern techniques with obvious implications for sample return from Mars. Macroscopic products of chemical weathering reactions in past Martian epochs are also expected in Martian surface materials. These products are expected not only as a result of reactions similar to those proceeding today but also due to aqueous reactions in past epochs in which liquid water was putatively present. It may prove very difficult or impossible, however, to determine definitively from the relic macroscopic product alone either the exact weathering process which led to its formation of the identity of its weathering parent mineral. The enormous advantages of studying the Martian chemical weathering by investigating the microscopic products of present-day chemical reactions on sample surfaces are very apparent.

  12. Chemical interactions between the present-day Martian atmosphere and surface minerals: Implications for sample return

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald; Fegley, Bruce

    1988-01-01

    Thermochemical and photochemical reactions between surface minerals and present-day atmospheric constituents are predicted to produce microscopic effects on the surface of mineral grains. Relevant reactions hypothesized in the literature include conversions of silicates and volcanic glasses to clay minerals, conversion of ferrous to ferric compounds, and formation of carbonates, nitrates, and sulfates. These types of surface-atmosphere weathering of minerals, biological potential of the surface environment, and atmospheric stability in both present and past Martian epochs. It is emphasized that the product of these reactions will be observable and interpretable on the microscopic surface layers of Martian surface rocks using modern techniques with obvious implications for sample return from Mars. Macroscopic products of chemical weathering reactions in past Martian epochs are also expected in Martian surface materials. These products are expected not only as a result of reactions similar to those proceeding today but also due to aqueous reactions in past epochs in which liquid water was putatively present. It may prove very difficult or impossible, however, to determine definitively from the relic macroscopic product alone either the exact weathering process which led to its formation of the identity of its weathering parent mineral. The enormous advantages of studying the Martian chemical weathering by investigating the microscopic products of present-day chemical reactions on sample surfaces are very apparent.

  13. Petroleum pollutant degradation by surface water microorganisms.

    PubMed

    Antić, Malisa P; Jovancićević, Branimir S; Ilić, Mila; Vrvić, Miroslav M; Schwarzbauer, Jan

    2006-09-01

    It is well known that the composition of petroleum or some of its processing products changes in the environment mostly under the influence of microorganisms. A series of experiments was conducted in order to define the optimum conditions for an efficient biodegradation of petroleum pollutant, or bioremediation of different segments of the environment. The aim of these investigations was to show to what extent the hydrocarbons of a petroleum pollutant are degraded by microbial cultures which were isolated as dominant microorganisms from a surface water of a wastewater canal of an oil refinery and a nitrogen plant. Biodegradation experiments were conducted on one paraffinic, and one naphthenic type of petroleum during a three month period under aerobic conditions, varying the following parameters: Inorganic (Kp) or an organic medium (Bh) with or without exposition to light. Microorganisms were analyzed in a surface water sample from a canal (Pancevo, Serbia), into which wastewater from an oil refinery and a nitrogen plant is released. The consortia of microorganisms were isolated from the water sample (most abundant species: Phormidium foveolarum--filamentous Cyanobacteria, blue-green algae and Achanthes minutissima, diatoms, algae). The simulation experiments of biodegradation were conducted with the biomass suspension and crude oils Sirakovo (Sir, paraffinic type) and Velebit (Ve, naphthenic type). After a three month period, organic substance was extracted by means of chloroform. In the extracts, the content of saturated hydrocarbons, aromatic hydrocarbons, alcohols and fatty acids was determined (the group composition). n-Alkanes and isoprenoid aliphatic alkanes, pristane and phytane, in the aliphatic fractions, were analyzed using gas chromatography (GC). Total isoprenoid aliphatic alkanes and polycyclic alkanes of sterane and triterpane types were analyzed by GC-MS. Paraffinic type petroleums have a significant loss of saturated hydrocarbons. For naphthenic

  14. Light Effect on Water Viscosity: Implication for ATP Biosynthesis.

    PubMed

    Sommer, Andrei P; Haddad, Mike Kh; Fecht, Hans-Jörg

    2015-07-08

    Previous work assumed that ATP synthase, the smallest known rotary motor in nature, operates at 100% efficiency. Calculations which arrive to this result assume that the water viscosity inside mitochondria is constant and corresponds to that of bulk water. In our opinion this assumption is not satisfactory for two reasons: (1) There is evidence that the water in mitochondria prevails to 100% as interfacial water. (2) Laboratory experiments which explore the properties of interfacial water suggest viscosities which exceed those of bulk water, specifically at hydrophilic interfaces. Here, we wish to suggest a physicochemical mechanism which assumes intramitochondrial water viscosity gradients and consistently explains two cellular responses: The decrease and increase in ATP synthesis in response to reactive oxygen species and non-destructive levels of near-infrared (NIR) laser light, respectively. The mechanism is derived from the results of a new experimental method, which combines the technique of nanoindentation with the modulation of interfacial water layers by laser irradiation. Results, including the elucidation of the principle of light-induced ATP production, are expected to have broad implications in all fields of medicine.

  15. Light Effect on Water Viscosity: Implication for ATP Biosynthesis

    PubMed Central

    Sommer, Andrei P.; Haddad, Mike Kh.; Fecht, Hans-Jörg

    2015-01-01

    Previous work assumed that ATP synthase, the smallest known rotary motor in nature, operates at 100% efficiency. Calculations which arrive to this result assume that the water viscosity inside mitochondria is constant and corresponds to that of bulk water. In our opinion this assumption is not satisfactory for two reasons: (1) There is evidence that the water in mitochondria prevails to 100% as interfacial water. (2) Laboratory experiments which explore the properties of interfacial water suggest viscosities which exceed those of bulk water, specifically at hydrophilic interfaces. Here, we wish to suggest a physicochemical mechanism which assumes intramitochondrial water viscosity gradients and consistently explains two cellular responses: The decrease and increase in ATP synthesis in response to reactive oxygen species and non-destructive levels of near-infrared (NIR) laser light, respectively. The mechanism is derived from the results of a new experimental method, which combines the technique of nanoindentation with the modulation of interfacial water layers by laser irradiation. Results, including the elucidation of the principle of light-induced ATP production, are expected to have broad implications in all fields of medicine. PMID:26154113

  16. Photochemical Transformation Processes in Sunlit Surface Waters

    NASA Astrophysics Data System (ADS)

    Vione, D.

    2012-12-01

    Photochemical reactions are major processes in the transformation of hardly biodegradable xenobiotics in surface waters. They are usually classified into direct photolysis and indirect or sensitised degradation. Direct photolysis requires xenobiotic compounds to absorb sunlight, and to get transformed as a consequence. Sensitised transformation involves reaction with transient species (e.g. °OH, CO3-°, 1O2 and triplet states of chromophoric dissolved organic matter, 3CDOM*), photogenerated by so-called photosensitisers (nitrate, nitrite and CDOM). CDOM is a major photosensitiser: is it on average the main source of °OH (and of CO3-° as a consequence, which is mainly produced upon oxidation by °OH of carbonate and bicarbonate) and the only important source of 1O2 and 3CDOM* [1, 2]. CDOM origin plays a key role in sensitised processes: allochthonous CDOM derived from soil runoff and rich in fulvic and humic substances is usually more photoactive than autochthonous CDOM (produced by in-water biological processes and mainly consisting of protein-like material) or of CDOM derived from atmospheric deposition. An interesting gradual evolution of CDOM origin and photochemistry can be found in mountain lakes across the treeline, which afford a gradual transition of allochthonous- autochtonous - atmopheric CDOM when passing from trees to alpine meadows to exposed rocks [3]. Another important issue is the sites of reactive species photoproduction in CDOM. While there is evidence that smaller molecular weight fractions are more photoactive, some studies have reported considerable 1O2 reactivity in CDOM hydrophobic sites and inside particles [4]. We have recently addressed the problem and found that dissolved species in standard humic acids (hydrodynamic diameter < 0.1 μm) account for the vast majority of 1O2 and triplet states photoproduction. In hydrophobic sites of particles, the formation rate of 1O2 is considerably lower than in the solution bulk [5], but the absence

  17. Effects of surface pressure on the properties of Langmuir monolayers and interfacial water at the air-water interface.

    PubMed

    Lin, Wei; Clark, Anthony J; Paesani, Francesco

    2015-02-24

    The effects of surface pressure on the physical properties of Langmuir monolayers of palmitic acid (PA) and dipalmitoylphosphatidic acid (DPPA) at the air/water interface are investigated through molecular dynamics simulations with atomistic force fields. The structure and dynamics of both monolayers and interfacial water are compared across the range of surface pressures at which stable monolayers can form. For PA monolayers at T = 300 K, the untilted condensed phase with a hexagonal lattice structure is found at high surface pressure, while the uniformly tilted condensed phase with a centered rectangular lattice structure is observed at low surface pressure, in agreement with the available experimental data. A state with uniform chain tilt but no periodic spatial ordering is observed for DPPA monolayers on a Na(+)/water subphase at both high and low surface pressures. The hydrophobic acyl chains of both monolayers pack efficiently at all surface pressures, resulting in a very small number of gauche defects. The analysis of the hydrogen-bonding structure/dynamics at the monolayer/water interface indicates that water molecules hydrogen-bonded to the DPPA head groups reorient more slowly than those hydrogen-bonded to the PA head groups, with the orientational dynamics becoming significantly slower at high surface pressure. Possible implications for physicochemical processes taking place on marine aerosols in the atmosphere are discussed.

  18. Communication: Interaction of BrO radical with the surface of water

    NASA Astrophysics Data System (ADS)

    Zhu, Chongqin; Gao, Yurui; Zhong, Jie; Huang, Yingying; Francisco, Joseph S.; Zeng, Xiao Cheng

    2016-12-01

    Solvation of a BrO radical in a slab of water is investigated using adaptive buffered force quantum mechanics/molecular mechanics (QM/MM) dynamics simulations. The simulation results show that the BrO radical exhibits preference towards the water surface with respect to the interior region of the water slab, despite BrO's high affinity to water. Another important finding is the weakening of (BrO)Br⋯O(water) interaction at the water surface due to competitive interactions between (BrO)Br⋯O(water) and (water)H⋯O(water). As such, the BrO-water slab interaction is dominated by (BrO)O⋯H(water) interaction, contrary to that in the gas phase, suggesting that the reactive site for the BrO radical at the air/water surface is more likely the Br site. The conclusion from this study can offer deeper insight into the reactivity of the BrO radical at the air/water interface, with regard to atmospheric implications.

  19. Communication: Interaction of BrO radical with the surface of water.

    PubMed

    Zhu, Chongqin; Gao, Yurui; Zhong, Jie; Huang, Yingying; Francisco, Joseph S; Zeng, Xiao Cheng

    2016-12-28

    Solvation of a BrO radical in a slab of water is investigated using adaptive buffered force quantum mechanics/molecular mechanics (QM/MM) dynamics simulations. The simulation results show that the BrO radical exhibits preference towards the water surface with respect to the interior region of the water slab, despite BrO's high affinity to water. Another important finding is the weakening of (BrO)Br⋯O(water) interaction at the water surface due to competitive interactions between (BrO)Br⋯O(water) and (water)H⋯O(water). As such, the BrO-water slab interaction is dominated by (BrO)O⋯H(water) interaction, contrary to that in the gas phase, suggesting that the reactive site for the BrO radical at the air/water surface is more likely the Br site. The conclusion from this study can offer deeper insight into the reactivity of the BrO radical at the air/water interface, with regard to atmospheric implications.

  20. Water vapor interactions with FeOOH particle surfaces

    NASA Astrophysics Data System (ADS)

    Song, Xiaowei; Boily, Jean-François

    2013-02-01

    Interactions between iron (oxyhydr)oxide particle surfaces and water are of fundamental importance to natural and technological processes. In this Letter, we probe the interactions between submicron-sized lepidocrocite (γ-FeOOH) surfaces and gaseous water using Fourier transform infrared spectroscopy. Formation of hydrogen bonds between different lepidocrocite surface OH functional groups and water was specifically monitored in the O-H stretching region. Molecular dynamics simulations of the dominant crystallographic terminations of these particles provided insights into interfacial water structures and hydrogen bonding networks. Theoretical power spectra were moreover used to validate interpretations of experimental spectra. This Letter constrains our understanding of incipient water adsorption reactions leading to thermodynamically stable and reversible thin water films at FeOOH particle surfaces. It also suggests that these water layers are structurally analogous precursors to those occurring at a FeOOH surfaces contacted with liquid water.

  1. Water resources data for Florida water year 2004volume 1A. northeast Florida surface water

    USGS Publications Warehouse

    Herrett, Thomas A.; Hess, Glen W.; House, Jon G.; Ruppert, Gregory P.; Courts, Mary-Lorraine

    2005-01-01

    Water resources data for the 2004 water year in Florida consist of continuous or daily discharge for 405 streams, periodic discharge for 12 streams, continuous or daily stage for 159 streams, periodic stage for 19 streams, peak stage and discharge for 30 streams; continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes; continuous ground-water levels for 408 wells, periodic ground-water levels for 1,157 wells; quality-of-water data for 140 surface-water sites and 239 wells. The data for northeast Florida include continuous or daily discharge for 140 streams, periodic discharge for 4 streams, continuous or daily stage for 58 streams, periodic stage for 3 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 10 lakes, periodic elevations for 20 lakes; continuous ground water levels for 50 wells, periodic ground-water levels for 522 wells; quality-of-water data for 40 surface-water sites and 66 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

  2. Water Resources Data, Florida, Water Year 2002, Volume 2A. South Florida Surface Water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2003-01-01

    Water resources data for 2002 water year in Florida consists of continuous or daily discharge for 392 streams, periodic discharge for 15 streams, continuous or daily stage for 191 streams, periodic stage for 13 stream, peak discharge for 33 streams, and peak stage for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes, continuous ground-water levels for 418 wells, periodic ground-water levels for 1287 wells, quality of water data for 116 surface-water sites, and 291 wells. The data for South Florida included continuous or daily discharge for 71 streams, continuous or daily stage for 49 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 238 wells, periodic ground-water levels for 260 wells, water quality for 24 surface-water sites, and 159 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

  3. Water resources data, Florida, water year 2005. Volume 2A: south Florida surface water

    USGS Publications Warehouse

    Price, C.; Overton, K.

    2006-01-01

    Water resources data for 2005 water year in Florida consists of continuous or daily discharge for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 stream, peak discharge for 28 streams, and peak stage for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, quality of water data for 211 surface-water sites, and 208 wells. The data for South Florida included continuous or daily discharge for 91 streams, continuous or daily stage for 62 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 248 wells, periodic ground-water levels for 187 wells, water quality for 54 surface-water sites, and 121 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

  4. Water Resources Data, Florida, Water Year 2003 Volume 2A: South Florida Surface Water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2004-01-01

    Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

  5. Water resources data-Florida water year 2004volume 2A: south Florida surface water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2005-01-01

    Water resources data for 2004 water year in Florida consists of continuous or daily discharge for 405 streams, periodic discharge for 12 streams, continuous or daily stage for 159 streams, periodic stage for 19 stream, peak discharge for 30 streams, and peak stage for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 408 wells, periodic ground-water levels for 1188 wells, quality of water data for 140 surface-water sites, and 240 wells. The data for South Florida included continuous or daily discharge for 86 streams, continuous or daily stage for 54 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 257 wells, periodic ground-water levels for 226 wells, water quality for 39 surface-water sites, and 149 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Florida.

  6. Water Resources Data, Florida, Water Year 2001, Volume 2A. South Florida Surface Water

    USGS Publications Warehouse

    Price, C.; Woolverton, J.; Overton, K.

    2002-01-01

    Water resources data for 2001 water year in Florida consists of continuous or daily discharge for 404 streams, periodic discharge for 15 streams, continuous or daily stage for 154 streams, periodic stage for 12 stream, peak discharge for 37 streams, and peak stage for 37 streams, continuous or daily elevations for 12 lakes, periodic elevations for 50 lakes, continuous ground-water levels for 426 wells, periodic ground-water levels for 1251 wells, quality of water data for 112 surface-water sites, and 235 wells. The data for South Florida included continuous or daily discharge for 89 streams, continuous or daily stage for 64 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 244 wells, periodic ground-water levels for 255 wells, water quality for 32 surface-water sites, and 166 wells. The data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

  7. Structure and reactivity of water at biomaterial surfaces.

    PubMed

    Vogler, E A

    1998-02-01

    Molecular self association in liquids is a physical process that can dominate cohesion (interfacial tension) and miscibility. In water, self association is a powerful organizational force leading to a three-dimensional hydrogen-bonded network (water structure). Localized perturbations in the chemical potential of water as by, for example, contact with a solid surface, induces compensating changes in water structure that can be sensed tens of nanometers from the point of origin using the surface force apparatus (SFA) and ancillary techniques. These instruments reveal attractive or repulsive forces between opposing surfaces immersed in water, over and above that anticipated by continuum theory (DLVO), that are attributed to a variable density (partial molar volume) of a more-or-less ordered water structure, depending on the water wettability (surface energy) of the water-contacting surfaces. Water structure at surfaces is thus found to be a manifestation of hydrophobicity and, while mechanistic/theoretical interpretation of experimental results remain the subject of some debate in the literature, convergence of experimental observations permit, for the first time, quantitative definition of the relative terms 'hydrophobic' and 'hydrophilic'. In particular, long-range attractive forces are detected only between surfaces exhibiting a water contact angle theta > 65 degrees (herein defined as hydrophobic surfaces with pure water adhesion tension tau O = gamma O cos theta < 30 dyn/cm where gamma O is water interfacial tension = 72.8 dyn/cm). Repulsive forces are detected between surfaces exhibiting theta < 65 degrees (hydrophilic surfaces, tau O > 30 dyn/cm). These findings suggest at least two distinct kinds of water structure and reactivity: a relatively less-dense water region against hydrophobic surfaces with an open hydrogen-bonded network and a relatively more-dense water region against hydrophilic surfaces with a collapsed hydrogen-bonded network. Importantly

  8. Floating Vegetated Mats For Improving Surface Water Quality

    USDA-ARS?s Scientific Manuscript database

    Contamination of surface and ground waters is an environmental concern. Pollution from both point and nonpoint sources can render water unsuitable for use. Surface waters of concern include streams, rivers, ponds, lakes, canals, and wastewater lagoons. Lagooned wastewater from confined animal feedi...

  9. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... non-point source pollution of waters of the United States that violates applicable legal requirements... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a...

  10. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the discharge of a nonpoint source of pollution to waters of the United States, including wetlands... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements....

  11. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF..., that violates any requirement of an area-wide or State-wide water quality management plan that has been... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water requirements....

  12. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to,...

  13. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to,...

  14. 40 CFR 258.27 - Surface water requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to,...

  15. Implications of Modeling Uncertainty for Water Quality Decision Making

    NASA Astrophysics Data System (ADS)

    Shabman, L.

    2002-05-01

    The report, National Academy of Sciences report, "Assessing the TMDL Approach to Water Quality Management" endorsed the "watershed" and "ambient water quality focused" approach" to water quality management called for in the TMDL program. The committee felt that available data and models were adequate to move such a program forward, if the EPA and all stakeholders better understood the nature of the scientific enterprise and its application to the TMDL program. Specifically, the report called for a greater acknowledgement of model prediction uncertinaity in making and implementing TMDL plans. To assure that such uncertinaity was addressed in water quality decision making the committee called for a commitment to "adaptive implementation" of water quality management plans. The committee found that the number and complexity of the interactions of multiple stressors, combined with model prediction uncertinaity means that we need to avoid the temptation to make assurances that specific actions will result in attainment of particular water quality standards. Until the work on solving a water quality problem begins, analysts and decision makers cannot be sure what the correct solutions are, or even what water quality goals a community should be seeking. In complex systems we need to act in order to learn; adaptive implementation is a concurrent process of action and learning. Learning requires (1) continued monitoring of the waterbody to determine how it responds to the actions taken and (2) carefully designed experiments in the watershed. If we do not design learning into what we attempt we are not doing adaptive implementation. Therefore, there needs to be an increased commitment to monitoring and experiments in watersheds that will lead to learning. This presentation will 1) explain the logic for adaptive implementation; 2) discuss the ways that water quality modelers could characterize and explain model uncertinaity to decision makers; 3) speculate on the implications

  16. The ultraviolet reflectance of Enceladus: Implications for surface composition

    NASA Astrophysics Data System (ADS)

    Hendrix, Amanda R.; Hansen, Candice J.; Holsclaw, Greg M.

    2010-04-01

    The reflectance of Saturn's moon Enceladus has been measured at far ultraviolet (FUV) wavelengths (115-190 nm) by Cassini's Ultraviolet Imaging Spectrograph (UVIS). At visible and near infrared (VNIR) wavelengths Enceladus' reflectance spectrum is very bright, consistent with a surface composed primarily of H 2O ice. At FUV wavelengths, however, Enceladus is surprisingly dark - darker than would be expected for pure water ice. Previous analyses have focused on the VNIR spectrum, comparing it to pure water ice (Cruikshank, D.P., Owen, T.C., Dalle Ore, C., Geballe, T.R., Roush, T.L., de Bergh, C., Sandford, S.A., Poulet, F., Benedix, G.K., Emery, J.P. [2005] Icarus, 175, 268-283) or pure water ice plus a small amount of NH 3 (Emery, J.P., Burr, D.M., Cruikshank, D.P., Brown, R.H., Dalton, J.B. [2005] Astron. Astrophys., 435, 353-362) or NH 3 hydrate (Verbiscer, A.J., Peterson, D.E., Skrutskie, M.F., Cushing, M., Helfenstein, P., Nelson, M.J., Smith, J.D., Wilson, J.C. [2006] Icarus, 182, 211-223). We compare Enceladus' FUV spectrum to existing laboratory measurements of the reflectance spectra of candidate species, and to spectral models. We find that the low FUV reflectance of Enceladus can be explained by the presence of a small amount of NH 3 and a small amount of a tholin in addition to H 2O ice on the surface. The presence of these three species (H 2O, NH 3, and a tholin) appears to satisfy not only the low FUV reflectance and spectral shape, but also the middle-ultraviolet to visible wavelength brightness and spectral shape. We expect that ammonia in the Enceladus plume is transported across the surface to provide a global coating.

  17. Physicochemical properties of concentrated Martian surface waters

    NASA Astrophysics Data System (ADS)

    Tosca, Nicholas J.; McLennan, Scott M.; Lamb, Michael P.; Grotzinger, John P.

    2011-05-01

    Understanding the processes controlling chemical sedimentation is an important step in deciphering paleoclimatic conditions from the rock records preserved on both Earth and Mars. Clear evidence for subaqueous sedimentation at Meridiani Planum, widespread saline mineral deposits in the Valles Marineris region, and the possible role of saline waters in forming recent geomorphologic features all underscore the need to understand the physical properties of highly concentrated solutions on Mars in addition to, and as a function of, their distinct chemistry. Using thermodynamic models predicting saline mineral solubility, we generate likely brine compositions ranging from bicarbonate-dominated to sulfate-dominated and predict their saline mineralogy. For each brine composition, we then estimate a number of thermal, transport, and colligative properties using established models that have been developed for highly concentrated multicomponent electrolyte solutions. The available experimental data and theoretical models that allow estimation of these physicochemical properties encompass, for the most part, much of the anticipated variation in chemistry for likely Martian brines. These estimates allow significant progress in building a detailed analysis of physical sedimentation at the ancient Martian surface and allow more accurate predictions of thermal behavior and the diffusive transport of matter through chemically distinct solutions under comparatively nonstandard conditions.

  18. Water Resources Data: New Jersey, Water Year 1998, Volume 1, Surface-Water Data

    USGS Publications Warehouse

    Reed, T.J.; Centinaro, G.L.; Dudek, J.F.; Corcino, V.; Stekroadt, G.C.; McTigure, R.C.

    1999-01-01

    This volume of the annual hydrologic data report of New Jersey is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and water quality provide the hydrologic information needed by state, local and federal agencies, and the private sector for developing and managing our Nation's land and water resources.

  19. Environmental setting of the upper Illinois River basin and implications for water quality

    USGS Publications Warehouse

    Arnold, Terri L.; Sullivan, Daniel J.; Harris, Mitchell A.; Fitzpatrick, Faith A.; Scudder, Barbara C.; Ruhl, Peter M.; Hanchar, Dorothea W.; Stewart, Jana S.

    1999-01-01

    The upper Illinois River Basin (UIRB) is the 10,949 square mile drainage area upstream from Ottawa, Illinois, on the Illinois River. The UIRB is one of 13 studies that began in 1996 as part of the U.S. Geological Survey?s National Water- Quality Assessment program. A compilation of environmental data from Federal, State, and local agencies provides a description of the environmental setting of the UIRB. Environmental data include natural factors such as bedrock geology, physiography and surficial geology, soils, vegetation, climate, and ecoregions; and human factors such as land use, urbanization trends, and population change. Characterization of the environmental setting is useful for understanding the physical, chemical, and biological characteristics of surface and ground water in the UIRB and the possible implications of that environmental setting for water quality. Some of the possible implications identified include depletion of dissolved oxygen because of high concentrations of organic matter in wastewater, increased flooding because of suburbanization, elevated arsenic concentrations in ground water because of weathering of shale bedrock, and decreasing ground-water levels because of heavy pumping of water from the bedrock aquifers.

  20. High-resolution mapping of global surface water and its long-term changes

    NASA Astrophysics Data System (ADS)

    Pekel, Jean-François; Cottam, Andrew; Gorelick, Noel; Belward, Alan S.

    2016-12-01

    The location and persistence of surface water (inland and coastal) is both affected by climate and human activity and affects climate, biological diversity and human wellbeing. Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions, statistical extrapolation of regional data and satellite imagery, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal. Losses in Australia and the USA linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water

  1. High-resolution mapping of global surface water and its long-term changes.

    PubMed

    Pekel, Jean-François; Cottam, Andrew; Gorelick, Noel; Belward, Alan S

    2016-12-15

    The location and persistence of surface water (inland and coastal) is both affected by climate and human activity and affects climate, biological diversity and human wellbeing. Global data sets documenting surface water location and seasonality have been produced from inventories and national descriptions, statistical extrapolation of regional data and satellite imagery, but measuring long-term changes at high resolution remains a challenge. Here, using three million Landsat satellite images, we quantify changes in global surface water over the past 32 years at 30-metre resolution. We record the months and years when water was present, where occurrence changed and what form changes took in terms of seasonality and persistence. Between 1984 and 2015 permanent surface water has disappeared from an area of almost 90,000 square kilometres, roughly equivalent to that of Lake Superior, though new permanent bodies of surface water covering 184,000 square kilometres have formed elsewhere. All continental regions show a net increase in permanent water, except Oceania, which has a fractional (one per cent) net loss. Much of the increase is from reservoir filling, although climate change is also implicated. Loss is more geographically concentrated than gain. Over 70 per cent of global net permanent water loss occurred in the Middle East and Central Asia, linked to drought and human actions including river diversion or damming and unregulated withdrawal. Losses in Australia and the USA linked to long-term droughts are also evident. This globally consistent, validated data set shows that impacts of climate change and climate oscillations on surface water occurrence can be measured and that evidence can be gathered to show how surface water is altered by human activities. We anticipate that this freely available data will improve the modelling of surface forcing, provide evidence of state and change in wetland ecotones (the transition areas between biomes), and inform water

  2. Section 11: Surface Water Pathway - Likelihood of Release

    EPA Pesticide Factsheets

    Surface water releases can include the threat to targets from overland flow of hazardous substances and from flooding or the threat from the release of hazardous substances to ground water and the subsequent discharge of contaminated ground w

  3. Water and Brines on Mars: Current Evidence and Implications for MSL

    NASA Astrophysics Data System (ADS)

    Martínez, G. M.; Renno, N. O.

    2013-06-01

    Liquid water is a basic ingredient for life as we know it. Therefore, in order to understand the habitability of other planets we must first understand the behavior of water on them. Mars is the most Earth-like planet in the solar system and it has large reservoirs of H2O. Here, we review the current evidence for pure liquid water and brines on Mars, and discuss their implications for future and current missions such as the Mars Science Laboratory. Neither liquid water nor liquid brines are currently stable on the surface of Mars, but they could be present temporarily in a few areas of the planet. Pure liquid water is unlikely to be present, even temporarily, on the surface of Mars because evaporation into the extremely dry atmosphere would inhibit the formation of the liquid phase, where the temperature and pressure are high enough so that water would neither freeze nor boil. The exception to this is that monolayers of liquid water, referred to as undercooled liquid interfacial water, could exist on most of the Martian surface. In a few places liquid brines could exist temporarily on the surface because they could form at cryogenic temperatures, near ice or frost deposits where sublimation could be inhibited by the presence of nearly saturated air. Both liquid water and liquid brines might exist in the shallow subsurface because even a thin layer of soil forms an effective barrier against sublimation allowing pure liquid water to form sporadically in a few places, or liquid brines to form over longer periods of time in large portions of the planet. At greater depths, ice deposits could melt where the soil conductivity is low enough to blanket the deeper subsurface effectively. This could cause the formation of aquifers if the deeper soil is sufficiently permeable and an impermeable layer exists below the source of water. The fact that liquid brines and groundwater are likely to exist on Mars has important implications for geochemistry, glaciology, mineralogy

  4. Wettability and surface chemistry of crystalline and amorphous forms of a poorly water soluble drug.

    PubMed

    Puri, Vibha; Dantuluri, Ajay K; Kumar, Mahesh; Karar, N; Bansal, Arvind K

    2010-05-12

    The present study compares energetics of wetting behavior of crystalline and amorphous forms of a poorly water soluble drug, celecoxib (CLB) and attempts to correlate it to their surface molecular environment. Wettability and surface free energy were determined using sessile drop contact angle technique and water vapor sorption energetics was measured by adsorption calorimetry. The surface chemistry was elucidated by X-ray photoelectron spectroscopy (XPS) and crystallographic evaluation. The two solid forms displayed distinctly different wetting with various probe liquids and in vitro dissolution media. The crystalline form surface primarily exhibited dispersive surface energy (47.3mJ/m(2)), while the amorphous form had a slightly reduced dispersive (45.2mJ/m(2)) and a small additional polar (4.8mJ/m(2)) surface energy. Calorimetric measurements, revealed the amorphous form to possess a noticeably high differential heat of absorption, suggesting hydrogen bond interactions between its polar energetic sites and water molecules. Conversely, the crystalline CLB form was found to be inert to water vapor sorption. The relatively higher surface polarity of the amorphous form could be linked to its greater oxygen-to-fluorine surface concentration ratio of 1.27 (cf. 0.62 for crystalline CLB), as determined by XPS. The crystallographic studies of the preferred cleavage plane (020) of crystalline CLB further supported its higher hydrophobicity. In conclusion, the crystalline and amorphous forms of CLB exhibited disparate surface milieu, which in turn can have implications on the surface mediated events.

  5. Patterns of Oversubscribed Water Services: Implications for Groundwater

    NASA Astrophysics Data System (ADS)

    Douglas, E. M.; Vorosmarty, C. J.

    2009-12-01

    Water resources, even at continental and global scales, show signs of water scarcity and stress. Prior work has shown that non-sustainable water use could be a non-trivial component of total withdrawals, a conclusion drawn from documentary evidence but one fraught with high uncertainty. We assessed water supply using a geospatial framework, which enabled calculations to be made of the degree to which fresh water withdrawals exceed locally accessible supplies and those in river corridors. Sources of water to accommodate this oversubscription include interbasin transfers, desalination, and groundwater overdraught. Successfully delivering fresh water under such conditions can also create impairment of inland surface waterways, especially when these become source waters themselves. We find the fraction of global fresh water oversubscription in the range of 10-15% of total human water use, under this condition. While the aggregate percentage is relatively small, overdraft tends to be focused in a few regions of the world and hence very substantial at the local to regional scale. Syndromes include those well-known but now shown to be pandemic: saltwater intrusion, land subsidence, pollution, and economic losses. We present a global mapping that shows good correspondence with documentary evidence corroborating the simulated patterns. We also see evidence for active responses pursued in response to these water stresses. These include so-called “hard path” supply-oriented strategies like the construction of water infrastructure, but also more management-oriented such as those that reduce use through efficiency gains, integrated management, and wastewater reuse. We also see impetus for privatization of water supplies in response to this scarcity.

  6. The glass-liquid transition of water on hydrophobic surfaces.

    PubMed

    Souda, Ryutaro

    2008-09-28

    Interactions of thin water films with surfaces of graphite and vitrified room-temperature ionic liquid [1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)])] were investigated using time-of-flight secondary ion mass spectrometry as a function of temperature and annealing time to elucidate the glass-liquid transition of water at the molecular level. Surface diffusion of water occurs at temperatures higher than 120 K, thereby forming three-dimensional clusters (a two-dimensional layer) on the [bmim][PF(6)] (graphite) surface. The hydrophobic effect of the surface decreases with increasing coverage of water; the bulklike properties evolve up to 40 ML, as evidenced by the occurrence of film dewetting at around the conventional glass transition temperature (140 K). Results also showed that aging is necessary for the water monolayer (a 40 ML water film) to dewet the graphite ([bmim][PF(6)]) surface. The occurrence of aging is explainable by the successive evolution of two distinct liquids during the glass-liquid transition: low density liquid is followed by supercooled liquid water. The water monolayer on graphite is characterized by the preferred orientation of unpaired OH groups toward the surface; this structure is arrested during the aging time despite the occurrence of surface diffusion. However, the water monolayer formed on the [bmim][PF(6)] surface agglomerates immediately after the commencement of surface diffusion. The structure of low density liquid tends to be arrested by the attractive interaction with the neighbors.

  7. Structure of water adsorbed on a mica surface

    SciTech Connect

    Park, Sung-Ho; Sposito, Garrison

    2002-01-29

    Monte Carlo simulations of hydration water on the mica (001) surface under ambient conditions revealed water molecules bound closely to the ditrigonal cavities in the surface, with a lateral distribution of approximately one per cavity, and water molecules interposed between K{sup +} counter ions in a layer situated about 2.5 {angstrom} from a surface O along a direction normal to the (001) plane. The calculated water O density profile was in quantitative agreement with recent X-ray reflectivity measurements indicating strong lateral ordering of the hydration water but liquid-like disorder otherwise.

  8. Relaxational dynamics of water molecules at protein surface

    NASA Astrophysics Data System (ADS)

    Dellerue, S.; Bellissent-Funel, M.-C.

    2000-08-01

    Relaxational dynamics of water molecules at the surface of a C-phycocyanin protein is studied by high resolution quasi-elastic neutron scattering. The neutron quasi-elastic spectra are well described by the α-relaxation process of mode coupling theory of supercooled liquids. The relaxation times of interfacial water exhibit a power law dependence on the wave vector Q. The average diffusion coefficient is 10 times lower than that of bulk water. This confirms that there is a retardation of water molecules at the protein surface which is in good agreement with the results of water at the surface of hydrophilic model systems.

  9. Spreading of Cholera through Surface Water

    NASA Astrophysics Data System (ADS)

    Bertuzzo, E.; Casagrandi, R.; Gatto, M.; Rodriguez-Iturbe, I.; Rinaldo, A.

    2009-12-01

    Cholera epidemics are still a major public health concern to date in many areas of the world. In order to understand and forecast cholera outbreaks, one of the most important factors is the role played by the environmental matrix in which the disease spreads. We study how river networks, acting as environmental corridors for pathogens, affect the spreading of cholera epidemics. The environmental matrix in which the disease spreads is constituted by different human communities and their hydrologic interconnections. Each community is characterized by its spatial position, population size, water resources availability and hygiene conditions. By implementing a spatially explicit cholera model we seek the effects on epidemic dynamics of: i) the topology and metrics of the pathogens pathways that connect different communities; ii) the spatial distribution of the population size; and iii) the spatial distributions and quality of surface water resources and public health conditions, and how they vary with population size. The model has been applied to study the space-time evolution of a well documented cholera epidemic occurred in the KwaZulu-Natal province of South Africa. The epidemic lasted for two years and involved about 140,000 confirmed cholera cases. The model does well in reproducing the distribution of the cholera cases during the two outbreaks as well as their spatial spreading. We further extend the model by deriving the speed of propagation of traveling fronts in the case of uniformly distributed systems for different topologies: one and two dimensional lattices and river networks. The derivation of the spreading celerity proves instrumental in establishing the overall conditions for the relevance of spatially explicit models. The conditions are sought by comparison between spreading and disease timescales. Consider a cholera epidemic that starts from a point and spreads throughout a finite size system, it is possible to identify two different timescales: i

  10. Hydraulic fracturing water use variability in the United States and potential environmental implications.

    PubMed

    Gallegos, Tanya J; Varela, Brian A; Haines, Seth S; Engle, Mark A

    2015-07-01

    A U.S. map of water volumes used to hydraulically fracture oil and gas wells, 2011-2014Hydraulic fracturing water volumes differ regionally across the U.S.Discussion of variation in water use and potential environmental implications.

  11. The polluted surface water exerts an influence on underground water and its environmental effect

    SciTech Connect

    Weng, H.

    1995-12-31

    The relationship between the polluted surface water flowing through urban areas and adjacent ground water resources in the southeast of China was systematically studied. The polluted surface water contained elevated concentrations of heavy metals in the sediment. When this water was directly used in irrigation or as fertilizer, the harmful components and heavy metals were transported from water to soil and were adsorbed by soil and plants. The health of local people who drank the ground water was threatened.

  12. Water ordering and surface relaxations at the hematite (110) water interface

    SciTech Connect

    Catalano, Jeffrey G.; Fenter, Paul; Park, Changyong

    2009-02-07

    Structural characterization of iron oxide-water interfaces provides insight into the mechanisms through which these minerals control contaminant fate and element cycling in soil, sedimentary, and groundwater systems. Ordering of interfacial water and structural relaxations at the hematite (1 1 0) surface have been investigated in situ using high-resolution specular X-ray reflectivity. These measurements demonstrate that relaxations are constrained to primarily the top ~5 Å of the surface. Near-surface iron atoms do not relax substantially, although the uppermost layer displays an increased distribution width, while the undercoordinated oxygens on the surface uniformly relaxed outward. Two sites of adsorbed water and additional layering of water farther from the surface were observed. Water fully covers the (1 1 0) surface and appears to form a continuous network extending into bulk solution, with positional order decreasing to that of a disordered bulk fluid within 1 nm. The arrangement of water is similar to that on the hematite (0 1 2) surface, which has a similar surface topography, although these surfaces display different vibrational amplitudes or positional disorder of adsorbed water molecules and average spacings of near-surface layered water. Comparison between these surfaces suggests that interfacial water ordering on hematite is controlled primarily by surface structure and steric constraints and that highly ordered water is likely common to most hematite-water interfaces.

  13. Surface Tension: The Ways of Water.

    ERIC Educational Resources Information Center

    Donalson-Sams, Marilyn

    1988-01-01

    Describes activities which help students understand several basic scientific concepts regarding water. Outlines objectives, materials needed, procedures, and questions to ask about student observations. Investigations include working with the self-sealing property of water, talcum powder, paper clips, and making water wetter. (RT)

  14. Surface Tension: The Ways of Water.

    ERIC Educational Resources Information Center

    Donalson-Sams, Marilyn

    1988-01-01

    Describes activities which help students understand several basic scientific concepts regarding water. Outlines objectives, materials needed, procedures, and questions to ask about student observations. Investigations include working with the self-sealing property of water, talcum powder, paper clips, and making water wetter. (RT)

  15. Implications of Subduction Rehydration for Earth's Deep Water Cycle

    NASA Astrophysics Data System (ADS)

    Ruepke, L. H.; Phipps Morgan, J.; Dixon, J.

    2006-12-01

    The presence of liquid water is the principle difference between our Earth and other planets in the solar system. The global ocean is the obvious surface expression of this. The 'standard model' for the genesis of the oceans is that they are exhalations from Earth's deep interior continually rinsed through surface rocks by the global hydrologic cycle. The question of how much water resides within the Earth's deep interior remains unresolved and is a matter of vigorous ongoing scientific debate. We have addressed the question of water distribution between the exosphere and the mantle throughout Earth's history with simple mass balance considerations. In our model, water is outgassed from the mantle into the exosphere (atmosphere + continental crust) during pressure-release melting at mid-ocean ridges and hotspots. Plate subduction may transport water back from the surface into the deeper mantle thereby 'closing' the global geologic water cycle. In series of some 5000 model runs we have thoroughly explored the mutual effect of model parameters. All models correctly predict the formation of the present-day oceans but differ in their predicted sea-level changes through time and in the amount of water in the present-day mantle. To distinguish which model runs are the most realistic we use geochemical constraints and observed sealevel changes during the Phanerozoic. Recently Dixon et al. [2002] estimated water concentrations for some of the major mantle components and concluded that the most primitive (FOZO) are significantly wetter than the recycling associated EM or HIMU mantle components and the even drier depleted mantle source that melts to form MORB. Sealevel changes over hundreds of million of years are notoriously bad constrained. But a maximum drop in sealevel of 400-600m appears to be an upper bound. We find that only those model runs are consistent with these constraints in which deep water subduction is limited and in which the present-day mantle is

  16. Activities affecting surface water resources: A general overview

    SciTech Connect

    Not Available

    1990-01-01

    In November 1987, P.E.I. signed a federal/provincial work-sharing arrangement on water resource management focusing on groundwater pollution, surface water degradation and estuarine eutrophication. The surface water program was designed to identify current surface water uses and users within 12 major watersheds across the Island containing 26 individual rivers, as well as problems arising due to practices that degrade the quality of surface water and restricts its value to other user groups. This report presents a general overview of the program, covering the general characteristics of the Island; operations in agriculture, fish and wildlife, forestry, recreation, fisheries, and industry; alterations of natural features of waterways; wetlands; additional watershed activities such as hydrometric stations and subdivision development; and activities affecting surface water resources such as sedimentation sources, pollution point sources and instream obstructions.

  17. Transport of Cryptosporidium parvum in Surface Waters: Interplay of Hydrodynamic Processes, Sediments, and Biofilms

    NASA Astrophysics Data System (ADS)

    Searcy, K. E.; Packman, A. I.; Atwill, E. R.; Harter, T.

    2005-05-01

    Understanding the movement of pathogens in the environment is necessary to ensure the safety and protection of municipal water supply systems. Cryptosporidium parvum is a human pathogen of particular concern as it is common in surface waters of the United States, it can survive for long periods of time in the environment, and it is difficult to disinfect in water treatment plants. The transport of oocysts through watersheds can be mediated by interactions with the stream channel and suspended particles in the water column. For example, the association of C. parvum oocysts with suspended particles can alter the effective physical properties of the oocysts and increase their settling velocity. The hydrodynamic coupling of the overlying water with the pore water of the sediment bed can carry oocysts from the surface water into the sediment bed. Surface-attached communities of microorganisms, called biofilms, are ubiquitous in surface water systems and can capture C. parvum oocysts. Laboratory experiments were conducted at multiple scales (flowcell, batch, and flume) to determine the association of oocysts with sediments and biofilm communities and to assess the impact of this association on C. parvum transport. The effects of flow conditions, water chemistry, sediment composition, biofilm composition, and biofilm structure on these associations were all evaluated. The experimental results demonstrate that oocyst-sediment-biofilm interactions have significant implications for the propagation of C. parvum oocysts through watersheds and should generally be considered when predicting the fate of pathogens in the environment.

  18. An ontology design pattern for surface water features

    USGS Publications Warehouse

    Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

    2014-01-01

    Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

  19. Adsorption mechanism of water molecule on goethite (010) surface

    NASA Astrophysics Data System (ADS)

    Xiu, Fangyuan; Zhou, Long; Xia, Shuwei; Yu, Liangmin

    2016-12-01

    Goethite widely exists among ocean sediments; it plays an important role in fixing heavy metals and adsorbing organic contaminants. So the understanding of the adsorbing process of water molecule on its surface will be very helpful to further reveal such environmental friendly processes. The configuration, electronic properties and interaction energy of water molecules adsorbed on pnma goethite (010) surface were investigated in detail by using density functional theory on 6-31G (d,p) basis set and projector- augment wave (PAW) method. The mechanism of the interaction between goethite surface and H2O was proposed. Despite the differences in total energy, there are four possible types of water molecule adsorption configurations on goethite (010) surface (Aa, Ab, Ba, Bb), forming coordination bond with surface Fe atom. Results of theoretical modeling indicate that the dissociation process of adsorbed water is an endothermic reaction with high activation energy. The dissociation of adsorbed water molecule is a proton transportation process between water's O atoms and surface. PDOS results indicate that the bonding between H2O and (010) surface is due to the overlapping of water's 2p orbitals and Fe's 3d orbitals. These results clarify the mechanism on how adsorbed water is dissociated on the surface of goethite and potentially provide useful information of the surface chemistry of goethite.

  20. Cost Implications in Achieving Alternative Water Quality Targets

    NASA Astrophysics Data System (ADS)

    Schleich, Joachim; White, David; Stephenson, Kurt

    1996-04-01

    Excessive nutrient loading poses significant water quality problems in many water bodies across the country. An important question that must be addressed when nutrient reduction policies are devised is where nutrient reduction targets will be applied within the watershed. This paper examines the cost implications of establishing three possible nutrient reduction targets in different locations along the Fox-Wolf River basin in northeast Wisconsin. A linear programming model calculates the total cost of achieving a 50% phosphorus load reduction target established in various locations throughout the basin. Two strategies establish phosphorus reduction targets for each of the 41 subwatersheds, and the third approach establishes a single 50% target reduction at Green Bay for the entire watershed. The results indicate that achieving target phosphorus reductions at the subwatershed level is over 4 times more expensive than achieving the same percentage phosphorus reduction for the watershed as a whole.

  1. Molecular dynamics studies of interfacial water at the alumina surface.

    SciTech Connect

    Argyris, Dr. Dimitrios; Ho, Thomas; Cole, David

    2011-01-01

    Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to {approx}10 {angstrom} from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior at distances greater than {approx}10 {angstrom} from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water?water interactions on the structural properties at the interface.

  2. Effect of Metal Surface on Molecular Behavior of Supercooled Water

    NASA Astrophysics Data System (ADS)

    Okawa, Seiji; Saito, Akio; Hosoya, Kazuhiro

    Study on surface effect of heterogeneous nucleation was investigated using molecular dynamics method with NPT ensemble. Around 1000 water molecules were used and set in a periodic cell. Platinum was selected as material for top and bottom surfaces, since its lattice constant fits closely with ice Ih. Temperature and pressure were set at 250 K and 0. 1 MPa, respectively, for each calculation. Behavior of ice Ih on fcc(111) surface was examined. It was found that the structure of ice remained stable in a case of platinum surface and the structure was destroyed in a case of having a slightly different lattice constant. Behavior of water on Pt surface was also investigated by varying the shape of the surface. Three types of surface were selected, namely, a flat surface, a surface with one projection and a surface with three projections. It was found that, in a case of a flat plate, water next to Pt surface was strongly influenced by the surface and was prevented from forming ice structure. In a case of having one projection, there was a tendency to form an ice structure near the surface. In a case of having three projections, however, the tendency was weakened. Hence, it was concluded that heterogeneous nucleation of water is affected by a lattice constant of the substance as well as the shape of the surface.

  3. Global water cycle and the coevolution of the Earth's interior and surface environment

    NASA Astrophysics Data System (ADS)

    Korenaga, Jun; Planavsky, Noah J.; Evans, David A. D.

    2017-04-01

    The bulk Earth composition contains probably less than 0.3% of water, but this trace amount of water can affect the long-term evolution of the Earth in a number of different ways. The foremost issue is the occurrence of plate tectonics, which governs almost all aspects of the Earth system, and the presence of water could either promote or hinder the operation of plate tectonics, depending on where water resides. The global water cycle, which circulates surface water into the deep mantle and back to the surface again, could thus have played a critical role in the Earth's history. In this contribution, we first review the present-day water cycle and discuss its uncertainty as well as its secular variation. If the continental freeboard has been roughly constant since the Early Proterozoic, model results suggest long-term net water influx from the surface to the mantle, which is estimated to be 3-4.5×1014 g yr-1 on the billion years time scale. We survey geological and geochemical observations relevant to the emergence of continents above the sea level as well as the nature of Precambrian plate tectonics. The global water cycle is suggested to have been dominated by regassing, and its implications for geochemical cycles and atmospheric evolution are also discussed. This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'.

  4. Global water cycle and the coevolution of the Earth's interior and surface environment.

    PubMed

    Korenaga, Jun; Planavsky, Noah J; Evans, David A D

    2017-05-28

    The bulk Earth composition contains probably less than 0.3% of water, but this trace amount of water can affect the long-term evolution of the Earth in a number of different ways. The foremost issue is the occurrence of plate tectonics, which governs almost all aspects of the Earth system, and the presence of water could either promote or hinder the operation of plate tectonics, depending on where water resides. The global water cycle, which circulates surface water into the deep mantle and back to the surface again, could thus have played a critical role in the Earth's history. In this contribution, we first review the present-day water cycle and discuss its uncertainty as well as its secular variation. If the continental freeboard has been roughly constant since the Early Proterozoic, model results suggest long-term net water influx from the surface to the mantle, which is estimated to be 3-4.5×10(14) g yr(-1) on the billion years time scale. We survey geological and geochemical observations relevant to the emergence of continents above the sea level as well as the nature of Precambrian plate tectonics. The global water cycle is suggested to have been dominated by regassing, and its implications for geochemical cycles and atmospheric evolution are also discussed.This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'. © 2017 The Author(s).

  5. Spatial variation of waterborne Escherichia coli - implications for routine water quality monitoring.

    PubMed

    Quilliam, Richard S; Clements, Katie; Duce, Caroline; Cottrill, Simon B; Malham, Shelagh K; Jones, Davey L

    2011-12-01

    Escherichia coli are often used as faecal indicator bacteria (FIB) to provide a measure of microbial pollution in recreational and shellfish harvesting waters. However, although model forecasts for predicting the concentrations of FIB in surface waters are becoming more robust, they suffer from an inconsistency in quantification methods and an understanding of the spatial variation of FIB within a water course. The aim of this study was to investigate the transverse spatial variation in E. coli numbers (as an indicator of faecal pollution) across the estuary of the River Conwy, UK. Water samples were collected from four transverse transects across the estuary. Spatial variation of E. coli was significantly different from one side of the river to the other, although was not correlated with depth or the physiochemical properties of the water. Subsequently, microbial water quality classifications on the two opposite banks suggested very different levels of pollution coming down the river. This work has shown that the side of the river that routine water monitoring samples are taken from can make a significant difference to the classification of microbial water quality. This has important implications for sampling strategies and the use of microbial source tracking (MST) techniques.

  6. Models of Fate and Transport of Pollutants in Surface Waters

    ERIC Educational Resources Information Center

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  7. Models of Fate and Transport of Pollutants in Surface Waters

    ERIC Educational Resources Information Center

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  8. Investigation of surface water behavior during glaze ice accretion

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Turnock, Stephen R.

    1990-01-01

    A series of experimental investigations that focused on isolating the primary factors that control the behavior of unfrozen surface water during glaze ice accretion were conducted. Detailed microvideo observations were made of glaze ice accretions on 2.54 cm diam cylinders in a closed-loop refrigerated wind tunnel. Distinct zones of surface water behavior were observed; a smooth wet zone in the stagnation region with a uniform water film, a rough zone where surface tension effects caused coalescence of surface water into stationary beads, and a zone where surface water ran back as rivulets. The location of the transition from the smooth to the rough zone was found to migrate towards the stagnation point with time. Comparative tests were conducted to study the effect of the substrate thermal and roughness properties on ice accretion. The importance of surface water behavior was evaluated by the addition of a surface tension reducing agent to the icing tunnel water supply, which significantly altered the accreted glaze ice shape. Measurements were made to determine the contact angle behavior of water droplets on ice. A simple multizone modification to current glaze ice accretion models was proposed to include the observed surface roughness behavior.

  9. Economic Impacts of Surface Mining on Household Drinking Water Supplies

    EPA Science Inventory

    This report provides information on the economic and social impacts of contaminated surface and ground water supplies on residents and households near surface mining operations. The focus is on coal slurry contamination of water supplies in Mingo County, West Virginia, and descr...

  10. Sampling procedure for lake or stream surface water chemistry

    Treesearch

    Robert Musselman

    2012-01-01

    Surface waters collected in the field for chemical analyses are easily contaminated. This research note presents a step-by-step detailed description of how to avoid sample contamination when field collecting, processing, and transporting surface water samples for laboratory analysis.

  11. Economic Impacts of Surface Mining on Household Drinking Water Supplies

    EPA Science Inventory

    This report provides information on the economic and social impacts of contaminated surface and ground water supplies on residents and households near surface mining operations. The focus is on coal slurry contamination of water supplies in Mingo County, West Virginia, and descr...

  12. Protecting Surface Water Systems on Forest Sites Through Herbicide Use

    Treesearch

    J.L. Michael; H.L. Gibbs; J.B. Fischer; E.C. Webber

    2000-01-01

    Sediment, nutrients, and pesticides are universally accepted as the greatest threats to surface water quality world-wide. Sedimentation in surface waters is a natural phenomenon, but is magnified by human activities. Intensive forest management practices, particularly road building, harvesting and planting site preparation, result in the greatest increases in erosion...

  13. Effect of Surface Energy on Freezing Temperature of Water.

    PubMed

    Zhang, Yu; Anim-Danso, Emmanuel; Bekele, Selemon; Dhinojwala, Ali

    2016-07-13

    Previous studies have found that superhydrophobic surfaces are effective in delaying freezing of water droplets. However, the freezing process of water droplets on superhydrophobic surfaces depends on factors such as droplet size, surface area, roughness, and cooling rate. The role of surface energy, independent of any other parameters, in delaying freezing of water is not understood. Here, we have used infrared-visible sum frequency generation spectroscopy (SFG) to study the freezing of water next to solid substrates with water contact angles varying from 5° to 110°. We find that the freezing temperature of water decreases with increasing surface hydrophobicity only when the sample volume is small (∼10 μL). For a larger volume of water (∼300 μL), the freezing temperature is independent of surface energy. For water next to the surfaces with contact angle ≥54°, we observe a strong SFG peak associated with highly coordinated water. This research sheds new light on understanding the key factors in designing new anti-icing coatings.

  14. Enhanced ordering of water at hydrophobic surfaces.

    PubMed

    Strazdaite, Simona; Versluis, Jan; Backus, Ellen H G; Bakker, Huib J

    2014-02-07

    We study the properties of water molecules adjacent to a hydrophobic molecular layer with vibrational sum-frequency generation spectroscopy. We find that the water molecules at D2O/hexane, D2O/heptane, and D2O/polydimethylsiloxane interfaces show an enhanced ordering and stronger hydrogen-bond interactions than the water molecules at a D2O/air interface. With increasing temperature (up to 80 °C) the water structure becomes significantly less ordered and the hydrogen bonds become weaker.

  15. Biogeochemistry of DMS in Surface Waters

    NASA Technical Reports Server (NTRS)

    Dacey, J. W. H.

    1997-01-01

    Dimethylsulfide (DMS) is important in influencing the formation of aerosols in the troposphere over large areas of the world's oceans. Understanding the dynamics of aerosols is important to understanding the earth's radiation balance. In evaluating the factors controlling DMS in the troposphere it is vital to understand the dynamics of DMS in the surface ocean. The biogeochemical processes controlling DMS concentration in seawater are myriad; modeling and theoretical estimation are problematic. At the beginning of this project we believed that we were on the verge of simplifying the ship-track measurement of DMS, and we proposed to deploy such a system to develop a database relating high frequency DMS measurements to biological and physicochemical and optical properties of surface water that can be quantified by remote sensing techniques. We designed a system to measure DMS concomitantly with other basic chemical and biological data in a flow-through system. The project was collaborative between Woods Hole Oceanographic Institution (WHOI) and Bermuda Biological Station for Research (BBSR). The project on which we are reporting was budgeted for only one year with a one year no-cost extension. At WHOI our effort was directed towards designing traps which would be used to concentrate DMS from seawater and allow storage for subsequent analysis. At that time, GC systems were too large for easy long-term deployment on a research vessel like R/V Weatherbird, so we focused on simplifying the shipboard sampling procedure. Initial studies of sample recovery with high levels of DMS suggested that Carboxen 1000, a relatively new carbon molecular sieve, could be used as a stable storage medium. The affinity of Carboxen for DMS is several orders of magnitude higher than gold wool (another adsorbent used for DMS collection) on a weight or volume basis. Furthermore, Carboxen's affinity for DMS is also far less susceptible to humidity than gold wool. Unfortunately, further

  16. Biogeochemistry of DMS in Surface Waters

    NASA Technical Reports Server (NTRS)

    Dacey, J. W. H.

    1997-01-01

    Dimethylsulfide (DMS) is important in influencing the formation of aerosols in the troposphere over large areas of the world's oceans. Understanding the dynamics of aerosols is important to understanding the earth's radiation balance. In evaluating the factors controlling DMS in the troposphere it is vital to understand the dynamics of DMS in the surface ocean. The biogeochemical processes controlling DMS concentration in seawater are myriad; modeling and theoretical estimation are problematic. At the beginning of this project we believed that we were on the verge of simplifying the ship-track measurement of DMS, and we proposed to deploy such a system to develop a database relating high frequency DMS measurements to biological and physicochemical and optical properties of surface water that can be quantified by remote sensing techniques. We designed a system to measure DMS concomitantly with other basic chemical and biological data in a flow-through system. The project was collaborative between Woods Hole Oceanographic Institution (WHOI) and Bermuda Biological Station for Research (BBSR). The project on which we are reporting was budgeted for only one year with a one year no-cost extension. At WHOI our effort was directed towards designing traps which would be used to concentrate DMS from seawater and allow storage for subsequent analysis. At that time, GC systems were too large for easy long-term deployment on a research vessel like R/V Weatherbird, so we focused on simplifying the shipboard sampling procedure. Initial studies of sample recovery with high levels of DMS suggested that Carboxen 1000, a relatively new carbon molecular sieve, could be used as a stable storage medium. The affinity of Carboxen for DMS is several orders of magnitude higher than gold wool (another adsorbent used for DMS collection) on a weight or volume basis. Furthermore, Carboxen's affinity for DMS is also far less susceptible to humidity than gold wool. Unfortunately, further

  17. The global topography of Mars and implications for surface evolution

    NASA Technical Reports Server (NTRS)

    Smith, D. E.; Zuber, M. T.; Solomon, S. C.; Phillips, R. J.; Head, J. W.; Garvin, J. B.; Banerdt, W. B.; Muhleman, D. O.; Pettengill, G. H.; Neumann, G. A.; Lemoine, F. G.; Abshire, J. B.; Aharonson, O.; Brown, C. D.; Hauck, S. A.; Ivanov, A. B.; McGovern, P. J.; Zwally, H. J.; Duxbury, T. C.

    1999-01-01

    Elevations measured by the Mars Orbiter Laser Altimeter have yielded a high-accuracy global map of the topography of Mars. Dominant features include the low northern hemisphere, the Tharsis province, and the Hellas impact basin. The northern hemisphere depression is primarily a long-wavelength effect that has been shaped by an internal mechanism. The topography of Tharsis consists of two broad rises. Material excavated from Hellas contributes to the high elevation of the southern hemisphere and to the scarp along the hemispheric boundary. The present topography has three major drainage centers, with the northern lowlands being the largest. The two polar cap volumes yield an upper limit of the present surface water inventory of 3.2 to 4.7 million cubic kilometers.

  18. Towards an improved and more flexible representation of water stress in coupled photosynthesis-stomatal conductance models; implications for simulated land surface fluxes and variables at various spatiotemporal scales

    NASA Astrophysics Data System (ADS)

    Egea, G.; Verhoef, A.; Vidale, P. L.; Black, E.; Van den Hoof, C.

    2012-04-01

    Coupled photosynthesis-stomatal conductance (A-gs) models are commonly used in ecosystem models to represent the exchange rate of CO2 and H2O between vegetation and the atmosphere. The ways these models account for water stress differ greatly among modelling schemes. This study provides insight into the impact of contrasting model configurations of water stress on the simulated leaf-level values of net photosynthesis (A), stomatal conductance (gs), the functional relationship among them and their ratio, the intrinsic water use efficiency (A/gs), as soil dries. A simple, yet versatile, normalized soil moisture dependent function was used to account for the effects of water stress on gs, on mesophyll conductance (gm ) and on the biochemical capacity (Egea et al., 2011). Model output was compared to leaf-level values obtained from the literature. The sensitivity analyses emphasized the necessity to combine both stomatal and non-stomatal limitations of A in coupled A-gs models to accurately capture the observed functional relationships A vs. gs and A/gs vs. gs in response to drought. Accounting for water stress in coupled A-gs models by imposing either stomatal or biochemical limitations of A, as commonly practiced in most ecosystem models, failed to reproduce the observed functional relationship between key leaf gas exchange attributes. A quantitative limitation analysis revealed that the general pattern of C3 photosynthetic response to water stress can be represented in coupled A-gs models by imposing the highest limitation strength to mesophyll conductance, then to stomatal conductance and finally to the biochemical capacity. This more realistic representation of soil water stress on the simulated leaf-level values of A and gs was embedded in the JULES (Joint UK Land Environment Simulator; Best et al., 2011), model and tested for a number of vegetation types, for which driving and flux verification data were available. These simulations provide an insight into the

  19. Sea-ice and surface water circulation, Alaskan continental shelf

    NASA Technical Reports Server (NTRS)

    Wright, F. F.; Sharma, G. D.; Burns, J. J. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Over 1500 water samples from surface and from standard hydrographic depths were collected during June and July 1973 from Bering Sea and Gulf of Alaska. The measurement of temperature, salinity, and productivity indicated that various distinct water masses cover the Bering Sea Shelf. The suspended load in surface waters will be correlated with the ERTS-1 imagery as it becomes available to delineate the surface water circulation. The movement of ice floes in the Bering Strait and Bering Sea indicated that movement of ice varies considerably and may depend on wind stress as well as ocean currents.

  20. Water resources data, New Jersey, water year 2005. Volume 1 - surface-water data

    USGS Publications Warehouse

    White, B.T.; Hoppe, H.L.; Centinaro, G.L.; Dudek, J.F.; Painter, B.S.; Protz, A.R.; Reed, T.J.; Shvanda, J.C.; Watson, A.F.

    2006-01-01

    Water-resources data for the 2005 water year for New Jersey are presented in three volumes, and consists of records of stage, discharge, and water-quality of streams; stage and contents of lakes and reservoirs; and water levels and water-quality of ground water. Volume 1 contains discharge records for 103 gaging stations; tide summaries at 28 tidal gaging stations; stage and contents at 34 lakes and reservoirs; and diversions from 50 surface-water sources. Also included are stage and discharge for 116 crest-stage partial-record stations, stage-only at 33 tidal crest-stage gages, and discharge for 155 low-flow partial-record stations. Locations of these sites are shown in figures 8-11. Additional discharge measurements were made at 222 miscellaneous sites that are not part of the systematic data-collection program. Discontinued station tables for gaging stations, crest-stage gages, tidal crest-stage and tidal gaging stations show historical coverage. The data in this report represent that part of the National Water Information System (NWIS) data collected by the United States Geological Survey (USGS). Hydrologic conditions are also described for this water year, including stream-flow, precipitation, reservoir conditions, and air temperatures.

  1. Water resources data, New Jersey, water year 2004-volume 1. surface-water data

    USGS Publications Warehouse

    Centinaro, G.L.; White, B.T.; Hoppe, H.L.; Dudek, J.F.; Protz, A.R.; Reed, T.J.; Shvanda, J.C.; Watson, A.F.

    2005-01-01

    Water-resources data for the 2004 water year for New Jersey are presented in three volumes, and consists of records of stage, discharge, and water-quality of streams; stage and contents of lakes and reservoirs; and water levels and water-quality of ground water. Volume 1 contains discharge records for 105 gaging stations; tide summaries at 27 tidal gaging stations; stage and contents at 39 lakes and reservoirs; and diversions from 51 surface-water sources. Also included are stage and discharge for 108 crest-stage partial-record stations, stage-only at 34 tidal crest-stage gages, and discharge for 124 low-flow partial-record stations. Locations of these sites are shown in figures 8-11. Additional discharge measurements were made at 131 miscellaneous sites that are not part of the systematic data-collection program. Discontinued station tables for gaging stations, crest-stage gages, tidal crest-stage and tidal gaging stations show historical coverage. The data in this report represent that part of the National Water Information System (NWIS) data collected by the United States Geological Survey (USGS). Hydrologic conditions are also described for this water year, including stream-flow, precipitation, reservoir conditions, and air temperatures.

  2. Water Interaction with Pristine and Nanopatterned Graphite Surfaces

    NASA Astrophysics Data System (ADS)

    Chakarov, Dinko

    2015-03-01

    We used number of surface sensitive techniques to study and compare the interaction of water with pristine surface of highly oriented pyrolytic graphite and model nanostructured surfaces fabricated by hole-mask colloidal lithography and oxygen plasma etching. Surface morphology and concentration of defects play important role and determine the amount of water bound in two- and three-dimensional hydrogen-bonded networks and thus the structure of ice films. Similarly, the amount and concentration of intersheet openings control the rate of water intercalation into graphite structures. The new findings are of particular interest for development of graphene exfoliation methods and for better understanding of graphene functionalization.

  3. Herbicide Metabolites in Surface Water and Groundwater: Introduction and Overview

    USGS Publications Warehouse

    Thurman, E.M.; Meyer, M.T.

    1996-01-01

    Several future research topics for herbicide metabolites in surface and ground water are outlined in this chapter. They are herbicide usage, chemical analysis of metabolites, and fate and transport of metabolites in surface and ground water. These three ideas follow the themes in this book, which are the summary of a symposium of the American Chemical Society on herbicide metabolites in surface and ground water. First, geographic information systems allow the spatial distribution of herbicide-use data to be combined with geochemical information on fate and transport of herbicides. Next these two types of information are useful in predicting the kinds of metabolites present and their probable distribution in surface and ground water. Finally, methods development efforts may be focused on these specific target analytes. This chapter discusses these three concepts and provides an introduction to this book on the analysis, chemistry, and fate and transport of herbicide metabolites in surface and ground water.

  4. Groundwater Storage vs. Surface Water Storage - Why Sustainability Requires a Different Management Framework

    NASA Astrophysics Data System (ADS)

    Mehl, S.; Davids, J. C.

    2015-12-01

    Storing water in times of excess for use in times of shortage is an essential water-management tool, especially in climates typified by precipitation in one season and demand in another. The three primary water storage mechanisms in the Western US, and much of the world in fact, are: seasonal snow pack, surface water reservoirs, and groundwater aquifers. In California, nearly every major river has one or more large dam and reservoir and current focus has shifted toward off-stream storage. In addition to California's surface reservoirs, groundwater aquifers provide huge volumes of water storage that are heavily utilized during times of drought. With California's new Sustainable Groundwater Management Act (SGMA) substantial attention is presently focused on developing strategies for using groundwater storage more effectively in conjunction with surface-storage reservoirs. However, compared to surface water storage, we need to think differently and develop new frameworks if we want to manage groundwater storage sustainably. Despite its immense capacity, groundwater storage is harder to manage because there are physical constraints to how fast water can be put into and withdrawn from aquifers, its boundaries are not as well defined as those of a surface reservoir, and it is part of a dynamic, porous media flow system where the Theis concepts of capture govern. Therefore, groundwater does not behave as a level pool like surface water reservoirs, which has several implications for effective management: 1) extraction/injection locations can have substantial impacts on the system, 2) interactions with the surface water systems can be nonlinear and complex and 3) hydraulic effects can continue long after pumping/injection has stopped. These nonlinear spatial and temporal responses, coupled with long time scales, makes management of groundwater storage much different than surface water storage. Furthermore, failure to fully understand these issues can lead to mismanagement

  5. Water-Mediated Interactions between Hydrophilic and Hydrophobic Surfaces.

    PubMed

    Kanduč, Matej; Schlaich, Alexander; Schneck, Emanuel; Netz, Roland R

    2016-09-06

    All surfaces in water experience at short separations hydration repulsion or hydrophobic attraction, depending on the surface polarity. These interactions dominate the more long-ranged electrostatic and van der Waals interactions and are ubiquitous in biological and colloidal systems. Despite their importance in all scenarios where the surface separation is in the nanometer range, the origin of these hydration interactions is still unclear. Using atomistic solvent-explicit molecular dynamics simulations, we analyze the interaction free energies of charge-neutral model surfaces with different elastic and water-binding properties. The surface polarity is shown to be the most important parameter that not only determines the hydration properties and thereby the water contact angle of a single surface but also the surface-surface interaction and whether two surfaces attract or repel. Elastic properties of the surfaces are less important. On the basis of surface contact angles and surface-surface binding affinities, we construct a universal interaction diagram featuring three different interaction regimes-hydration repulsion, cavitation-induced attraction-and for intermediate surface polarities-dry adhesion. On the basis of scaling arguments and perturbation theory, we establish simple combination rules that predict the interaction behavior for combinations of dissimilar surfaces.

  6. Adsorption of n-alkane vapours at the water surface.

    PubMed

    Biscay, Frédéric; Ghoufi, Aziz; Malfreyt, Patrice

    2011-06-21

    Monte Carlo simulations are reported here to predict the surface tension of the liquid-vapour interface of water upon adsorption of alkane vapours (methane to hexane). A decrease of the surface tension has been established from n-pentane. A correlation has been evidenced between the decrease of the surface tension and the absence of specific arrangement at the water surface for n-pentane and n-hexane. The thermodynamic stability of the adsorption layer and the absence of film for longer alkanes have been checked through the calculation of a potential of mean force. This complements the work recently published [Ghoufi et al., Phys. Chem. Chem. Phys., 2010, 12, 5203] concerning the adsorption of methane at the water surface. The decrease of the surface tension has been interpreted in terms of the degree of hydrogen bonding of water molecules at the liquid-vapour interface upon adsorption.

  7. Long-term changes in net radiation at the Earth's surface: uncertainties and implications

    NASA Astrophysics Data System (ADS)

    Sheffield, Justin; Coccia, Gabriele; Siemann, Amanda; Wood, Eric

    2014-05-01

    Net radiation at the earth's surface plays a key role in terrestrial water, energy and carbon fluxes, but there is large uncertainty in its variation over decadal time scales. Globally, surface and satellite measurements indicate global dimming in solar radiation over many regions since the mid-20th century and then brightening over recent decades due to changes in cloudiness and aerosols. Changes in longwave radiation are driven by long-term increases in greenhouse gases and inter-annual variations in short-lived constituents such as dust and black carbon. These increases are partially offset, however, by increases in surface temperature. Current estimates of these components of the net radiation balance from satellite remote sensing are inconsistent because of inhomogeneities from changes in satellites, sensor calibration, retrieval algorithms, and so on, in addition to systematic biases. Estimates from direct ground observations are hampered by sparse spatial networks and often short-term records, and estimates based on denser networks of meteorological data are affected by errors in empirical radiation models. Some of the largest uncertainties are in the characterization of the global distribution and temporal changes in surface shortwave albedo and infrared emissivity, especially in regions with seasonal and patchy snow cover. This paper presents comparisons of legacy satellite-derived datasets (e.g. ISCCP, GEWEX/SRB) and recently developed datasets based on updated algorithms and homogenized data sources (e.g. NASA Princeton-Measures, HIRS) in the context of long-term changes in the net radiation balance at the earth's surface. We compare these with ground observations and empirical estimates based on meteorological data from in-situ sources and reanalysis. In particular we focus on the uncertainties in the magnitude and variation in surface albedo and emissivity, and their contribution to uncertainties in net radiation. We discuss the implications of these

  8. Surface-Water Quality-Assurance Plan for the USGS Wisconsin Water Science Center

    USGS Publications Warehouse

    Garn, H.S.

    2007-01-01

    This surface-water quality-assurance plan documents the standards, policies, and procedures used by the Wisconsin Water Science Center of the U.S. Geological Survey, Water Resources Discipline, for activities related to the collection, processing, storage, analysis, management, and publication of surface-water data. The roles and responsibilities of Water Science Center personnel in following these policies and procedures including those related to safety and training are presented.

  9. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause...

  10. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause...

  11. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause...

  12. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause...

  13. Interfacial thermodynamics of confined water near molecularly rough surfaces

    PubMed Central

    Mittal, Jeetain; Hummer, Gerhard

    2012-01-01

    We study the effects of nanoscopic roughness on the interfacial free energy of water confined between solid surfaces. SPC/E water is simulated in confinement between two infinite planar surfaces that differ in their physical topology: one is smooth and the other one is physically rough on a nanometer length scale. The two thermodynamic ensembles considered, with constant pressure either normal or parallel to the walls, correspond to different experimental conditions. We find that molecular-scale surface roughness significantly increases the solid-liquid interfacial free energy compared to the smooth surface. For our surfaces with a water-wall interaction energy minimum of −1.2 kcal/mol, we observe a transition from a hydrophilic surface to a hydrophobic surface at a roughness amplitude of about 3 Å and a wave length of 11.6 Å, with the interfacial free energy changing sign from negative to positive. In agreement with previous studies of water near hydrophobic surfaces, we find an increase in the isothermal compressibility of water with increasing surface roughness. Interestingly, average measures of the water density and hydrogen-bond number do not contain distinct signatures of increased hydrophobicity. In contrast, a local analysis indicates transient dewetting of water in the valleys of the rough surface, together with a significant loss of hydrogen bonds, and a change in the dipole orientation toward the surface. These microscopic changes in the density, hydrogen bonding, and water orientation contribute to the large increase in the interfacial free energy, and the change from a hydrophilic to a hydrophobic character of the surface. PMID:21043431

  14. The influence of lithology on surface water sources

    EPA Science Inventory

    Understanding the temporal and spatial variability of surface water sources within a basin is vital to our ability to manage the impacts of climate variability and land cover change. Water stable isotopes can be used as a tool to determine geographic and seasonal sources of water...

  15. Variability in surface-subsurface hydrologic interactions and implications for nutrient retention in an arid-land stream

    NASA Astrophysics Data System (ADS)

    Dent, C. Lisa; Grimm, Nancy B.; Martí, EugèNia; Edmonds, Jennifer W.; Henry, Julia Curro; Welter, Jill R.

    2007-12-01

    Hydrologic interactions among biogeochemically active stream subsystems affect material export downstream. We combined a conservative tracer addition with measurements of water table elevation and nutrient concentrations of surface and subsurface water to examine hydrologic interactions among surface and subsurface subsystems and their implications for stream biogeochemistry. We injected bromide (Br-) into a 400-m reach of Sycamore Creek, a losing stream in central Arizona, for 15 d and monitored changes in concentration in three subsystems: surface, parafluvial, and riparian zones. Additionally, we collected water samples from these subsystems for nutrient analyses. Water flowed from surface to subsurface zones as expected in this losing stream, but a significant amount of subsurface water (17% of surface discharge in the reach) returned to the surface. Within the parafluvial subsystem, median transport time (Tmed) in two gravel bars differed substantially (from 2 to 30 h and from 6 to >300 h, respectively, for upper and lower bars), and varied significantly with depth in the lower bar (mean (±SE) Tmed = 190 ± 20 h at 30 cm compared to 101 ± 18 h at 110 cm). Flow paths from the surface to parafluvial and riparian zones, and subsequently back to the surface stream, differ from patterns in mesic areas, where water moves laterally and vertically towards the surface stream. Estimates of nutrient retention for the stream reach varied four fold in response to simulated changes in lateral subsurface connections and the configuration of subsystems. Thus at this scale, accurate nutrient budgets require an understanding of surface-subsurface connections and hydrologic parameters.

  16. Simulating continental surface waters: An application to Holocene northern Africa

    SciTech Connect

    Coe, M.T.

    1997-07-01

    A model (SWAM) to predict surface waters (lakes and wetlands) on the scale of atmospheric general circulation models is developed. SWAM is based on a linear reservoir hydrologic model and is driven by runoff, precipitation, evaporation, topography, and water transport directions. SWAM is applied to the modern climate using observed estimates of the hydrologic variables and a 5{prime} {times} 5{prime} digital terrain model to represent topography. It simulates the surface water area of northern Africa (about 1% of the land area) in reasonable agreement with observed estimates (0.65%). A middle Holocene (6000 yr BP) simulation using the results of the GENESIS atmospheric general circulation model (AGCM) illustrates the sensitivity of the simulated surface waters to climatic changes and the model`s utility as a diagnostic tool for AGCMs. SWAM and GENESIS capture the general pattern of climate change 6000 yr BP. There is an increase in the simulated surface water area from about 1% to about 3% of the land area, including an increase in the area of Lake Chad by about five times and extensive surface water throughout northern Mali, consistent with observed patterns of surface water change during the Holocene. Limitations in the modeling of surface waters appear to result from the relatively coarse resolution of global elevation data. 73 refs., 6 figs., 2 tabs.

  17. Water resources data, Iowa, water year 2001, Volume 2. surface water--Missouri River basin, and ground water

    USGS Publications Warehouse

    Nalley, G.M.; Gorman, J.G.; Goodrich, R.D.; Miller, V.E.; Turco, M.J.; Linhart, S.M.

    2002-01-01

    The Water Resources Division of the U.S. Geological Survey, in cooperation with State, county, municipal, and other Federal agencies, obtains a large amount of data pertaining to the water resources of Iowa each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make this data readily available to interested parties outside of the Geological Survey, the data is published annually in this report series entitled “Water Resources Data - Iowa” as part of the National Water Data System. Water resources data for water year 2001 for Iowa consists of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs; and water levels and water quality of ground water. This report, in two volumes, contains stage or discharge records for 132 gaging stations; stage records for 9 lakes and reservoirs; water-quality records for 4 gaging stations; sediment records for 13 gaging stations; and water levels for 163 ground-water observation wells. Also included are peak-flow data for 92 crest-stage partial-record stations, water-quality data from 86 municipal wells, and precipitation data collected at 6 gaging stations and 2 precipitation sites. Additional water data were collected at various sites not included in the systematic data-collection program, and are published here as miscellaneous measurements and analyses. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating local, State, and Federal agencies in Iowa.Records of discharge or stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological Survey water-supply papers entitled “Surface Water Supply of the United States.” Through September 30, 1960, these water-supply papers were published in an annual series; during 1961-65 and 1966-70, they

  18. Implementation of remote-sensed surface water condition into a land surfaces model

    NASA Astrophysics Data System (ADS)

    Byun, Ui-Yong; Sung, Hyun Min; Hong, Je-Woo; Hong, Jinkyu; Kunstmann, Harald; Arnault, Joel

    2016-04-01

    We will present our current efforts to incorporate remote-sensed surface water conditions into a land surface model in the Weather Research and Forecasting model (WRF) for better representation of cropland in East Asia. In this presentation, we introduce the model development and discuss its regional impacts on hydrological cycle in perspectives of the PBL-surface interactions and surface evapotranspiration tagging.

  19. Layers of Porous Superhydrophobic Surfaces for Robust Water Repellency

    NASA Astrophysics Data System (ADS)

    Ahmadi, Farzad; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team

    2015-11-01

    In nature, birds exhibit multiple layers of superhydrophobic feathers that repel water. Inspired by bird feathers, we utilize porous superhydrophobic surfaces and compare the wetting and dewetting characteristics of a single surface to stacks of multiple surfaces. The superhydrophobic surfaces were submerged in water in a closed chamber. Pressurized gas was regulated to measure the critical pressure for the water to fully penetrate through the surfaces. In addition to using duck feathers, two-tier porous superhydrophobic surfaces were fabricated to serve as synthetic mimics with a controlled surface structure. The energy barrier for the wetting transition was modeled as a function of the number of layers and their orientations with respect to each other. Moreover, after partial impalement into a subset of the superhydrophobic layers, it was observed that a full dewetting transition was possible, which suggests that natural organisms can exploit their multiple layers to prevent irreversible wetting.

  20. Water Quality Indicators Guide [and Teacher's Handbook]: Surface Waters.

    ERIC Educational Resources Information Center

    Terrell, Charles R.; Perfetti, Patricia Bytnar

    This guide aids in finding water quality solutions to problems from sediment, animal wastes, nutrients, pesticides, and salts. The guide allows users to learn the fundamental concepts of water quality assessment by extracting basic tenets from geology, hydrology, biology, ecology, and wastewater treatment. An introduction and eight chapters are…

  1. Crocodylus niloticus (Crocodilia) is highly sensitive to water surface waves.

    PubMed

    Grap, Nadja J; Monzel, Anna S; Kohl, Tobias; Bleckmann, Horst

    2015-10-01

    Crocodiles show oriented responses to water surface wave stimuli but up to now behavioral thresholds are missing. This study determines the behavioral thresholds of crocodilians to water surface waves. Nile crocodiles (Crocodylus niloticus) were conditioned to respond to single-frequency water surface wave stimuli (duration 1150 ms, frequency 15, 30, 40, 60 and 80 Hz), produced by blowing air onto the water surface. Our study shows that C. niloticus is highly sensitive to capillary water surface waves. Threshold values decreased with increasing frequency and ranged between 10.3 μm (15 Hz) and 0.5 μm (80 Hz) peak-to-peak wave amplitude. For the frequencies 15 Hz and 30 Hz the sensitivity of one spectacled caiman (Caiman crocodilus) to water surface waves was also tested. Threshold values were 12.8 μm (15 Hz) down to 1.76 μm (30 Hz), i.e. close to the threshold values of C. niloticus. The surface wave sensitivity of crocodiles is similar to the surface wave sensitivity of semi-aquatic insects and fishing spiders but does not match the sensitivity of surface-feeding fishes which is higher by one to two orders of magnitude. Copyright © 2015 Elsevier GmbH. All rights reserved.

  2. Optimizing water resources management in large river basins with integrated surface water-groundwater modeling: A surrogate-based approach

    NASA Astrophysics Data System (ADS)

    Wu, Bin; Zheng, Yi; Wu, Xin; Tian, Yong; Han, Feng; Liu, Jie; Zheng, Chunmiao

    2015-04-01

    Integrated surface water-groundwater modeling can provide a comprehensive and coherent understanding on basin-scale water cycle, but its high computational cost has impeded its application in real-world management. This study developed a new surrogate-based approach, SOIM (Surrogate-based Optimization for Integrated surface water-groundwater Modeling), to incorporate the integrated modeling into water management optimization. Its applicability and advantages were evaluated and validated through an optimization research on the conjunctive use of surface water (SW) and groundwater (GW) for irrigation in a semiarid region in northwest China. GSFLOW, an integrated SW-GW model developed by USGS, was employed. The study results show that, due to the strong and complicated SW-GW interactions, basin-scale water saving could be achieved by spatially optimizing the ratios of groundwater use in different irrigation districts. The water-saving potential essentially stems from the reduction of nonbeneficial evapotranspiration from the aqueduct system and shallow groundwater, and its magnitude largely depends on both water management schemes and hydrological conditions. Important implications for water resources management in general include: first, environmental flow regulation needs to take into account interannual variation of hydrological conditions, as well as spatial complexity of SW-GW interactions; and second, to resolve water use conflicts between upper stream and lower stream, a system approach is highly desired to reflect ecological, economic, and social concerns in water management decisions. Overall, this study highlights that surrogate-based approaches like SOIM represent a promising solution to filling the gap between complex environmental modeling and real-world management decision-making.

  3. Studies of the viscoelastic properties of water confined between surfaces of specified chemical nature.

    SciTech Connect

    Houston, Jack E.; Grest, Gary Stephen; Moore, Nathan W.; Feibelman, Peter J.

    2010-09-01

    This report summarizes the work completed under the Laboratory Directed Research and Development (LDRD) project 10-0973 of the same title. Understanding the molecular origin of the no-slip boundary condition remains vitally important for understanding molecular transport in biological, environmental and energy-related processes, with broad technological implications. Moreover, the viscoelastic properties of fluids in nanoconfinement or near surfaces are not well-understood. We have critically reviewed progress in this area, evaluated key experimental and theoretical methods, and made unique and important discoveries addressing these and related scientific questions. Thematically, the discoveries include insight into the orientation of water molecules on metal surfaces, the premelting of ice, the nucleation of water and alcohol vapors between surface asperities and the lubricity of these molecules when confined inside nanopores, the influence of water nucleation on adhesion to salts and silicates, and the growth and superplasticity of NaCl nanowires.

  4. Interaction of Water with Metal Surfaces

    DTIC Science & Technology

    1994-02-18

    Government This document has been approved for public release and sale; its distribution is unlimited 94-06693 94 2 28 1104 IIIi Ih im1lii P Best...label w) To begin, consider a perfect crystal surface in which the basic vectors of the lattice are a, and a 2. Next consider a point particle p at r...pp, zp) where zp is the perpendicular distance above the surface and pp is the projection of rp onto the surface plane. The label p stands for 0 or

  5. Cigarette Smoke Toxins Deposited on Surfaces: Implications for Human Health

    PubMed Central

    Martins-Green, Manuela; Adhami, Neema; Frankos, Michael; Valdez, Mathew; Goodwin, Benjamin; Lyubovitsky, Julia; Dhall, Sandeep; Garcia, Monika; Egiebor, Ivie; Martinez, Bethanne; Green, Harry W.; Havel, Christopher; Yu, Lisa; Liles, Sandy; Matt, Georg; Destaillats, Hugo; Sleiman, Mohammed; Gundel, Laura A.; Benowitz, Neal; Jacob, Peyton; Hovell, Melbourne; Winickoff, Jonathan P.; Curras-Collazo, Margarita

    2014-01-01

    Cigarette smoking remains a significant health threat for smokers and nonsmokers alike. Secondhand smoke (SHS) is intrinsically more toxic than directly inhaled smoke. Recently, a new threat has been discovered – Thirdhand smoke (THS) – the accumulation of SHS on surfaces that ages with time, becoming progressively more toxic. THS is a potential health threat to children, spouses of smokers and workers in environments where smoking is or has been allowed. The goal of this study is to investigate the effects of THS on liver, lung, skin healing, and behavior, using an animal model exposed to THS under conditions that mimic exposure of humans. THS-exposed mice show alterations in multiple organ systems and excrete levels of NNAL (a tobacco-specific carcinogen biomarker) similar to those found in children exposed to SHS (and consequently to THS). In liver, THS leads to increased lipid levels and non-alcoholic fatty liver disease, a precursor to cirrhosis and cancer and a potential contributor to cardiovascular disease. In lung, THS stimulates excess collagen production and high levels of inflammatory cytokines, suggesting propensity for fibrosis with implications for inflammation-induced diseases such as chronic obstructive pulmonary disease and asthma. In wounded skin, healing in THS-exposed mice has many characteristics of the poor healing of surgical incisions observed in human smokers. Lastly, behavioral tests show that THS-exposed mice become hyperactive. The latter data, combined with emerging associated behavioral problems in children exposed to SHS/THS, suggest that, with prolonged exposure, they may be at significant risk for developing more severe neurological disorders. These results provide a basis for studies on the toxic effects of THS in humans and inform potential regulatory policies to prevent involuntary exposure to THS. PMID:24489722

  6. Interim Enhanced Surface Water Treatment Rule Documents

    EPA Pesticide Factsheets

    The IESWTR balances the need for treatment with potential increases in disinfection by -products. The materials found on this page are intended to assist public water systems and state in the implementation of the IESWTR.

  7. OCCURRENCE OF ENTERIC VIRUSES IN SURFACE WATERS

    EPA Science Inventory

    Human enteric viruses cause a number of diseases when individuals are exposed to contaminated drinking & recreational waters. Vaccination against poliovirus has virtually eliminated poliomyelitis from the planet. Other members of enterovirus group cause numerous diseases. Hepatit...

  8. OCCURRENCE OF ENTERIC VIRUSES IN SURFACE WATERS

    EPA Science Inventory

    Human enteric viruses cause a number of diseases when individuals are exposed to contaminated drinking & recreational waters. Vaccination against poliovirus has virtually eliminated poliomyelitis from the planet. Other members of enterovirus group cause numerous diseases. Hepatit...

  9. Bioinspired aquatic microrobot capable of walking on water surface like a water strider.

    PubMed

    Zhang, Xinbin; Zhao, Jie; Zhu, Qing; Chen, Ning; Zhang, Mingwen; Pan, Qinmin

    2011-07-01

    Walking on the water surface is a dream of humans, but it is exactly the way of life for some aquatic insects. In this study, a bionic aquatic microrobot capable of walking on the water surface like a water strider was reported. The novel water strider-like robot consisted of ten superhydrophobic supporting legs, two miniature dc motors, and two actuating legs. The microrobot could not only stand effortlessly but also walk and turn freely on the water surface, exhibiting an interesting motion characteristic. A numerical model describing the interface between the partially submerged leg and the air-water surface was established to fully understand the mechanism for the large supporting force of the leg. It was revealed that the radius and water contact angle of the legs significantly affect the supporting force. Because of its high speed, agility, low cost, and easy fabrication, this microrobot might have a potential application in water quality surveillance, water pollution monitoring, and so on.

  10. Summary of surface-water quality, ground-water quality, and water withdrawals for the Spirit Lake Reservation, North Dakota

    USGS Publications Warehouse

    Vining, Kevin C.; Cates, Steven W.

    2006-01-01

    Available surface-water quality, ground-water quality, and water-withdrawal data for the Spirit Lake Reservation were summarized. The data were collected intermittently from 1948 through 2004 and were compiled from U.S. Geological Survey databases, North Dakota State Water Commission databases, and Spirit Lake Nation tribal agencies. Although the quality of surface water on the reservation generally is satisfactory, no surface-water sources are used for consumable water supplies. Ground water on the reservation is of sufficient quality for most uses. The Tokio and Warwick aquifers have better overall water quality than the Spiritwood aquifer. Water from the Spiritwood aquifer is used mostly for irrigation. The Warwick aquifer provides most of the consumable water for the reservation and for the city of Devils Lake. Annual water withdrawals from the Warwick aquifer by the Spirit Lake Nation ranged from 71 million gallons to 122 million gallons during 2000-04.

  11. The European water framework directive: water quality classification and implications to engineering planning.

    PubMed

    Achleitner, Stefan; De Toffol, Sara; Engelhard, Carolina; Rauch, Wolfgang

    2005-04-01

    The European Water framework directive (WFD) is probably the most important environmental management directive that has been enacted over the last decade in the European Union. The directive aims at achieving an overall good ecological status in all European water bodies. In this article, we discuss the implementation steps of the WFD and their implications for environmental engineering practice while focusing on rivers as the main receiving waters. Arising challenges for engineers and scientists are seen in the quantitative assessment of water quality, where standardized systems are needed to estimate the biological status. This is equally of concern in engineering planning, where the prediction of ecological impacts is required. Studies dealing with both classification and prediction of the ecological water quality are reviewed. Further, the combined emission-water quality approach is discussed. Common understanding of this combined approach is to apply the most stringent of either water quality or emission standard to a certain case. In contrast, for example, the Austrian water act enables the application of only the water quality based approach--at least on a temporary basis.

  12. Water accommodation on ice and organic surfaces: insights from environmental molecular beam experiments.

    PubMed

    Kong, Xiangrui; Thomson, Erik S; Papagiannakopoulos, Panos; Johansson, Sofia M; Pettersson, Jan B C

    2014-11-26

    Water uptake on aerosol and cloud particles in the atmosphere modifies their chemistry and microphysics with important implications for climate on Earth. Here, we apply an environmental molecular beam (EMB) method to characterize water accommodation on ice and organic surfaces. The adsorption of surface-active compounds including short-chain alcohols, nitric acid, and acetic acid significantly affects accommodation of D2O on ice. n-Hexanol and n-butanol adlayers reduce water uptake by facilitating rapid desorption and function as inefficient barriers for accommodation as well as desorption of water, while the effect of adsorbed methanol is small. Water accommodation is close to unity on nitric-acid- and acetic-acid-covered ice, and accommodation is significantly more efficient than that on the bare ice surface. Water uptake is inefficient on solid alcohols and acetic acid but strongly enhanced on liquid phases including a quasi-liquid layer on solid n-butanol. The EMB method provides unique information on accommodation and rapid kinetics on volatile surfaces, and these studies suggest that adsorbed organic and acidic compounds need to be taken into account when describing water at environmental interfaces.

  13. Microcystins (cyanobacterial toxins) in surface waters of rural Bangladesh: pilot study.

    PubMed

    Welker, Martin; Khan, Saleha; Haque, Md Mahfuzul; Islam, Sirajul; Khan, Nurul Huda; Chorus, Ingrid; Fastner, Jutta

    2005-12-01

    In Bangladesh the exposure of millions of inhabitants to water from (shallow) tube wells contaminated with high geogenic loads of arsenic is a major concern. As an alternative to the costly drilling of deep wells, the return to the use of surface water as a source of drinking water is considered. In addition to the well-known hazards of water borne infectious diseases associated with the use of surface water, recently the potential public health implications of toxic cyanobacteria have been recognized. As a first step towards a risk assessment for cyanotoxins in Bangladesh surface waters, seston samples of 79 ponds were analysed in late summer 2002 for the presence of cyanobacteria and microcystins (MCYST), the most frequently detected cyanobacterial toxins worldwide. Microcystins could be detected in 39 ponds, mostly together with varying abundance of potentially microcystin-producing genera such as Microcystis, Planktothrix and Anabaena. Total microcystin concentrations ranged between <0.1 and > 1,000 microg l(-1), and more than half of the positive samples contained high concentrations of more than 10 microg l(-1). The results clearly show that concentrations of microcystins well above the provisional WHO guideline value of 1 microg l(-1) MCYST-LR can be frequently detected in Bangladesh ponds. Thus, an increasing use of surface water for human consumption introduces a risk of replacing one health hazard by another and therefore needs to be accompanied by cyanotoxin hazard assessments.

  14. Interfacial entropy of water on rigid hydrophobic surfaces.

    PubMed

    Taherian, Fereshte; Leroy, Frédéric; van der Vegt, Nico F A

    2013-08-06

    A simple theoretical model is proposed for computing the interfacial entropy of water at rigid hydrophobic surfaces. The interfacial entropy, which is not considered in mean field models of static wettability, is evaluated from the fluctuations of the water-surface dispersion energy at the single particle level and represents the configurational bias imposed on the fluid molecules by the attractive external potential of a solid wall. A comparison with results obtained from molecular dynamics simulations shows that the model quantitatively describes the entropy loss of water when a water-vapor interface turns to water in contact with hydrophobic surfaces such as graphene, graphite, and diamond, while it overestimates this quantity on hydrophilic surfaces.

  15. High coverage water adsorption on CuO(011) surface.

    PubMed

    Yu, Xiaohu; Zhang, Xuemei

    2017-07-19

    Spin-polarized density functional theory calculations (GGA+U) and atomic thermodynamics have been used to study the adsorption of water on the CuO(011) surface at different coverages. It was found that H2O molecular adsorption on CuO(011) surface is energetically favorable for one H2O molecule, but dissociative adsorption is preferred for two and three molecules, while a mixed molecular and dissociative coadsorption is favorable for four water molecules. The phase diagram of water adsorption on the CuO(011) surface shows that the adsorption of three and four water molecules is favorable thermodynamically. Different single-water adsorption states were analyzed by the Boltzmann model at different temperatures. The adsorption energy is contributed to by the surface uncoordinated copper and oxygen atoms, and by hydrogen chemical bonding. The energetic trends are related to the underlying electronic mechanisms.

  16. Liquid water can slip on a hydrophilic surface

    PubMed Central

    Ho, Tuan Anh; Papavassiliou, Dimitrios V.; Lee, Lloyd L.; Striolo, Alberto

    2011-01-01

    Understanding and predicting the behavior of water, especially in contact with various surfaces, is a scientific challenge. Molecular-level understanding of hydrophobic effects and their macroscopic consequences, in particular, is critical to many applications. Macroscopically, a surface is classified as hydrophilic or hydrophobic depending on the contact angle formed by a water droplet. Because hydrophobic surfaces tend to cause water slip whereas hydrophilic ones do not, the former surfaces can yield self-cleaning garments and ice-repellent materials whereas the latter cannot. The results presented herein suggest that this dichotomy might be purely coincidental. Our simulation results demonstrate that hydrophilic surfaces can show features typically associated with hydrophobicity, namely liquid water slip. Further analysis provides details on the molecular mechanism responsible for this surprising result. PMID:21911406

  17. Interaction between water cluster ions and mica surface

    SciTech Connect

    Ryuto, Hiromichi Ohmura, Yuki; Nakagawa, Minoru; Takeuchi, Mitsuaki; Takaoka, Gikan H.

    2014-03-15

    Water cluster ion beams were irradiated on mica surfaces to investigate the interaction between molecular cluster ions and a mica surface. The contact angle of the mica surface increased with increasing dose of the water cluster ion beam, but the increase in the contact angle was smaller than that induced by an ethanol cluster ion beam. The surface roughness also increased with increasing dose of the water cluster ion beam, whereas the intensity of K 2p x-ray photoelectron spectroscopy peaks decreased with increasing dose of the water cluster ion beam. The decrease in the number of potassium atoms together with the increase in the surface roughness may be the causes of the increase in the contact angle.

  18. Quality of Surface Water in Missouri, Water Year 2007

    USGS Publications Warehouse

    Otero-Benitez, William; Davis, Jerri V.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2007 water year (October 1, 2006 through September 30, 2007), data were collected at 67 stations including two U.S. Geological Survey National Stream Quality Accounting Network stations and one spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, dissolved nitrite plus nitrte, total phosphorus, dissolved and total recoverable lead and zinc, and selected pesticide data summaries are presented for 64 of these stations, which primarily have been classified in groups corresponding to the physiography of the State, main land use, or unique station types. In addition, a summary of hydrologic conditions in the State during water year 2007 is presented.

  19. Desert Beetle-Inspired Superwettable Patterned Surfaces for Water Harvesting.

    PubMed

    Yu, Zhenwei; Yun, Frank F; Wang, Yanqin; Yao, Li; Dou, Shixue; Liu, Kesong; Jiang, Lei; Wang, Xiaolin

    2017-09-01

    With the impacts of climate change and impending crisis of clean drinking water, designing functional materials for water harvesting from fog with large water capacity has received much attention in recent years. Nature has evolved different strategies for surviving dry, arid, and xeric conditions. Nature is a school for human beings. In this contribution, inspired by the Stenocara beetle, superhydrophilic/superhydrophobic patterned surfaces are fabricated on the silica poly(dimethylsiloxane) (PDMS)-coated superhydrophobic surfaces using a pulsed laser deposition approach with masks. The resultant samples with patterned wettability demonstrate water-harvesting efficiency in comparison with the silica PDMS-coated superhydrophobic surface and the Pt nanoparticles-coated superhydrophilic surface. The maximum water-harvesting efficiency can reach about 5.3 g cm(-2) h(-1) . Both the size and the percentage of the Pt-coated superhydrophilic square regions on the patterned surface affect the condensation and coalescence of the water droplet, as well as the final water-harvesting efficiency. The present water-harvesting strategy should provide an avenue to alleviate the water crisis facing mankind in certain arid regions of the world. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Intermittent Surface Water Connectivity: Fill and Spill Vs. Fill ...

    EPA Pesticide Factsheets

    Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

  1. Intermittent Surface Water Connectivity: Fill and Spill vs. Fill ...

    EPA Pesticide Factsheets

    Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

  2. Reactions and clustering of water with silica surface.

    PubMed

    Ma, Yuchen; Foster, A S; Nieminen, R M

    2005-04-08

    The interaction between silica surface and water is an important topic in geophysics and materials science, yet little is known about the reaction process. In this study we use first-principles molecular dynamics to simulate the hydrolysis process of silica surface using large cluster models. We find that a single water molecule is stable near the surface but can easily dissociate at three-coordinated silicon atom defect sites in the presence of other water molecules. These extra molecules provide a mechanism for hydrogen transfer from the original water molecule, hence catalyzing the reaction. The two-coordinated silicon atom is inert to the water molecule, and water clusters up to pentamer could be stably adsorbed at this site at room temperature.

  3. Georgia's Surface-Water Resources and Streamflow Monitoring Network, 2008

    USGS Publications Warehouse

    ,

    2008-01-01

    Surface water provides 5 billion gallons per day, or 78 percent, of the total freshwater used (including thermoelectric) in Georgia (Fanning, 2003). Climate, geology, and landforms control the natural distribution of Georgia's water resources. Georgia is a 'headwaters' State, with most of the rivers beginning in northern Georgia and increasing in size downstream (see map at right for major watersheds). Surface water is the primary source of water in the northern one-half of the State, including the Atlanta metropolitan area, where limited ground-water resources are difficult to obtain. In Georgia, periodic droughts exacerbate competition for surface-water supplies. Many areas of Georgia also face a threat of flooding because of spring frontal thunderstorms and the potential for hurricanes from both the Atlantic Ocean and Gulf of Mexico. As the population of Georgia increases, these flood risks will increase with development in flood-risk zones, particularly in the coastal region.

  4. Surveillance of perchlorate in ground water, surface water and bottled water in Kerala, India.

    PubMed

    Nadaraja, Anupama Vijaya; Puthiyaveettil, Prajeesh Gangadharan; Bhaskaran, Krishnakumar

    2015-01-01

    Perchlorate is an emerging water contaminant that disrupts normal functioning of human thyroid gland and poses serious threat to health, especially for pregnant women, fetus and children. High level of perchlorate contamination in fresh water sources at places nearby ammonium perchlorate (rocket fuel) handled in bulk is reported in this study. Of 160 ground water samples analyzed from 27 locations in the State Kerala, 58 % had perchlorate above detection limit (2 μg/L) and the highest concentration observed was 7270 μg/L at Ernakulam district, this value is ~480 times higher than USEPA drinking water equivalent level (15 μg/L). Perchlorate was detected in all surface water samples analyzed (n = 10) and the highest value observed was 355 μg/L in Periyar river (a major river in the State). The bottled drinking water (n = 5) tested were free of perchlorate. The present study underlines the need for frequent screening of water sources for perchlorate contamination around places the chemical is handled in bulk. It will help to avoid human exposure to high levels of perchlorate.

  5. Water droplets interaction with super-hydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Yunying; Saito, Nagahiro; Nae, Florin Andrei; Inoue, Yasushi; Takai, Osamu

    2006-09-01

    Static and dynamic behavior of water droplets on various super-hydrophobic (SH) surfaces were investigated. First, SH plant leaves were used as samples and we found out that surface nanostructure has a great influence on the droplets dynamic behavior. Then, we made biomimetic structures by depositing SH films through microwave-plasma enhanced chemical vapor deposition (MPECVD). Next, SH surfaces were fabricated by covering previously roughened SiO x films with self-assembled monolayers (SAMs). The substrates were then charged with static electricity, and water droplets falling on tilted charged surfaces leaped up or run uphill at high speeds, proving that not only the surface nanostructure but also its chemical endgroups have a great effect on the water droplets motion on SH surfaces.

  6. Triclosan in water, implications for human and environmental health.

    PubMed

    Olaniyan, L W B; Mkwetshana, N; Okoh, A I

    2016-01-01

    Triclosan (TCS) is a broad spectrum antibacterial agent present as an active ingredient in some personal care products such as soaps, toothpastes and sterilizers. It is an endocrine disrupting compound and its increasing presence in water resources as well as in biosolid-amended soils used in farming, its potential for bioaccumulation in fatty tissues and toxicity in aquatic organisms are a cause for concern to human and environmental health. TCS has also been detected in blood, breast milk, urine and nails of humans. The significance of this is not precisely understood. Data on its bioaccumulation in humans are also lacking. Cell based studies however showed that TCS is a pro-oxidant and may be cytotoxic via a number of mechanisms. Uncoupling of oxidative phosphorylation appears to be prevailing as a toxicity mechanism though the compound's role in apoptosis has been cited. TCS is not known to be carcinogenic per se in vitro but has been reported to promote tumourigenesis in the presence of a carcinogen, in mice. Recent laboratory reports appear to support the view that TCS oestrogenicity as well as its anti-oestrogenicity play significant role in cancer progression. Results from epidemiological studies on the effect of TCS on human health have implicated the compound as responsible for certain allergies and reproductive defects. Its presence in chlorinated water also raises toxicity concern for humans as carcinogenic metabolites such as chlorophenols may be generated in the presence of the residual chlorine. In this paper, we carried out a detailed overview of TCS pollution and the implications for human and environmental health.

  7. Investigation of surface water behavior during glaze ice accretion

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Turnock, Stephen R.

    1988-01-01

    Microvideo observations of glaze ice accretions on 1-in-diameter cylinders in a closed-loop refrigerated wind tunnel were obtained to study factors controlling the behavior of unfrozen surface water during glaze ice accretion. Three zones of surface water behavior were noted, each with a characteristic roughness. The effect of substrate thermal and roughness properties on ice accretions was also studied. The contact angle and hysteresis were found to increase sharply at temperatures just below 0 C, explaining the high resistance to motion of water beads observed on accreting glaze ice surfaces. Based on the results, a simple multizone modification to the current glaze ice accretion model is proposed.

  8. Surface reactions of carbon dioxide at the adsorbed water-iron oxide interface.

    PubMed

    Baltrusaitis, Jonas; Grassian, Vicki H

    2005-06-30

    Despite the fact that carbon dioxide is an abundant atmospheric gas with profound environmental implications, there is little information on the reaction of carbon dioxide at the adsorbed water-oxide interface. In this study, the chemistry of carbon dioxide at the adsorbed water-iron oxide interface is investigated with FTIR spectroscopy. As shown here, the thin water layer on the iron oxide surface plays an important role in the surface chemistry of carbon dioxide. In particular, adsorbed water enhances CO(2) uptake, undergoes isotope exchange with CO(2) in O(18)-labeled experiments, and influences the chemical nature of the predominant adsorbed product on the surface from bicarbonate to carbonate. The resultant thin water film is acidic in nature from the reaction of CO(2). The IR spectrum recorded of adsorbed carbonate at the adsorbed water-iron oxide interface is remarkably similar to that at the bulk liquid water-iron oxide interface. Since reactions in thin water films estimated to be approximately 2 layers will play a role in a number of environmental processes, it is essential to understand the chemistry of these "wet" interfaces with atmospheric gases.

  9. Differential contributions of archaeal ammonia oxidizer ecotypes to nitrification in coastal surface waters.

    PubMed

    Smith, Jason M; Casciotti, Karen L; Chavez, Francisco P; Francis, Christopher A

    2014-08-01

    The occurrence of nitrification in the oceanic water column has implications extending from local effects on the structure and activity of phytoplankton communities to broader impacts on the speciation of nitrogenous nutrients and production of nitrous oxide. The ammonia-oxidizing archaea, responsible for carrying out the majority of nitrification in the sea, are present in the marine water column as two taxonomically distinct groups. Water column group A (WCA) organisms are detected at all depths, whereas Water column group B (WCB) are present primarily below the photic zone. An open question in marine biogeochemistry is whether the taxonomic definition of WCA and WCB organisms and their observed distributions correspond to distinct ecological and biogeochemical niches. We used the natural gradients in physicochemical and biological properties that upwelling establishes in surface waters to study their roles in nitrification, and how their activity--ascertained from quantification of ecotype-specific ammonia monooxygenase (amoA) genes and transcripts--varies in response to environmental fluctuations. Our results indicate a role for both ecotypes in nitrification in Monterey Bay surface waters. However, their respective contributions vary, due to their different sensitivities to surface water conditions. WCA organisms exhibited a remarkably consistent level of activity and their contribution to nitrification appears to be related to community size. WCB activity was less consistent and primarily constrained to colder, high nutrient and low chlorophyll waters. Overall, the results of our characterization yielded a strong, potentially predictive, relationship between archaeal amoA gene abundance and the rate of nitrification.

  10. Thin Water Films at Multifaceted Hematite Particle Surfaces.

    PubMed

    Boily, Jean-François; Yeşilbaş, Merve; Uddin, Munshi Md Musleh; Baiqing, Lu; Trushkina, Yulia; Salazar-Alvarez, Germàn

    2015-12-08

    Mineral surfaces exposed to moist air stabilize nanometer- to micrometer-thick water films. This study resolves the nature of thin water film formation at multifaceted hematite (α-Fe2O3) nanoparticle surfaces with crystallographic faces resolved by selected area electron diffraction. Dynamic vapor adsorption (DVA) in the 0-19 Torr range at 298 K showed that these particles stabilize water films consisting of up to 4-5 monolayers. Modeling of these data predicts water loadings in terms of an "adsorption regime" (up to 16 H2O/nm(2)) involving direct water binding to hematite surface sites, and of a "condensation regime" (up to 34 H2O/nm(2)) involving water binding to hematite-bound water nanoclusters. Vibration spectroscopy identified the predominant hematite surface hydroxo groups (-OH, μ-OH, μ3-OH) through which first layer water molecules formed hydrogen bonds, as well as surface iron sites directly coordinating water molecules (i.e., as geminal η-(OH2)2 sites). Chemometric analyses of the vibration spectra also revealed a strong correspondence in the response of hematite surface hydroxo groups to DVA-derived water loadings. These findings point to a near-saturation of the hydrogen-bonding environment of surface hydroxo groups at a partial water vapor pressure of ∼8 Torr (∼40% relative humidity). Classical molecular dynamics (MD) resolved the interfacial water structures and hydrogen bonding populations at five representative crystallographic faces expressed in these nanoparticles. Simulations of single oriented slabs underscored the individual roles of all (hydro)oxo groups in donating and accepting hydrogen bonds with first layer water in the "adsorption regime". These analyses pointed to the preponderance of hydrogen bond-donating -OH groups in the stabilization of thin water films. Contributions of μ-OH and μ3-OH groups are secondary, yet remain essential in the stabilization of thin water films. MD simulations also helped resolve crystallographic

  11. Interactions between ground water and surface water in the Suwannee River basin, Florida

    USGS Publications Warehouse

    Katz, B.G.; DeHan, R.S.; Hirten, J.J.; Catches, J.S.

    1997-01-01

    Ground water and surface water constitute a single dynamic system in roost parts of the Suwannee River basin due to the presence of karat features that facilitate the interaction between the surface and subsurface. Low radon-222 concentrations (below background levels) and enriched amounts of oxygen-18 and deuterium in ground water indicate mixing with surface water in parts of the basin. Comparison of surface water and regional ground water flow patterns indicate that boundaries for ground water basins typically do not coincide with surface water drainage subbasins. There are several areas in the basin where ground water flow that originates outside of the Suwannee River basin crosses surface water basin boundaries during both low-flow and high-flow conditions. In a study area adjacent to the Suwannee River that consists predominantly of agricultural land use, 18 wells tapping the Upper Floridan aquifer and 7 springs were sampled three times during 1990 through 1994 for major dissolved inorganic constituents, trace elements, and nutrients. During a period of above normal rainfall that resulted in high river stage and high ground water levels in 1991, the combination of increased amounts of dissolved organic carbon and decreased levels of dissolved oxygen in ground water created conditions favorable for the natural reduction of nitrate by denitrification reactions in the aquifer. As a result, less nitrate was discharged by ground water to the Suwannee River.

  12. Towards improved water quality assessment: comparision of surface water sampling strategies

    NASA Astrophysics Data System (ADS)

    Schneider, P.; Hetzenauer, H.; Doppler, T.

    2012-04-01

    In research and governmental water quality monitoring studies, clear guidelines for experimental design of monitoring campaigns are often unavailable, leading to flawed or ambiguous data sets. Not only are the data difficult to interpret, but incorrect conclusions and resulting policy recommendations can have far-reaching implications. Inadequate sampling devices or strategies are often responsible for sampling artifacts. These artifacts can obscure real variations in the environment. This is especially critical when considering nutrients, pollutants or environmental tracers, which are highly dependent on flow dynamics, and vary with discharge fluctuations. In this presentation we give an overview of sampling strategies, methods, and new devices using case studies from research catchments in Switzerland and Germany and an international watershed (Lake Constance). We compared various 'active' samplers (event-triggered sampling, time-proportional composite sampling, volume-proportional composite sampling) with two different types of passive samplers for several events in different catchments. Passive samplers have particular strength in remote catchments (especially for isotope sampling in higher altitudes), while their results are limited when applied in larger peri-alpine streams. We summarize our main findings and recommend a sampling guideline for surface water bodies concerning sampling device, method and strategy.

  13. Water loss from Venus: Implications for the Earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Richardson, S. M.; Pollack, J. B.; Reynolds, R. T.

    1985-01-01

    The atmosphere of Venus outgassed rapidly as a result of planetary heating during accretion, resulting in massive water loss. The processes affecting atmospheric chemistry following accretion have consisted largely of hydrogen escape and internal re-equilibrium. The initial bulk composition of Venus and Earth are assumed to have been roughly similar. Chemical speciation on Venus was controlled by the temperature and oxygen buffering capacity of the surface magma. It is also assumed that the surfaces of planetary bodies of the inner solar system were partly or wholly molten during accretion with a temperature estimated at 1273 to 1573 K. To investigate the range of reasonable initial atmospheric compositions on Venus, limits have to be set for the proportion of total hydrogen and the buffered fugacity of oxygen. Using the C/H ratio of 0.033 set for Earth, virtually all of the water generated during outgassing must later have been lost in order to bring the current CO2/H2O ratio for Venus up to its observed value of 10 sup 4 to 10 sup 5. The proportion of H2O decreases in model atmospheres with successfully higher C/H values, ultimately approaching the depleted values currently observed on Venus. Increasing C/H also results in a rapid increase in CO/H2O and provides an efficient mechanism for water loss by the reaction CO+H2O = CO2 + H2. This reaction, plus water loss mechanisms involving crustal iron, could have removed a very large volume of water from the Venusian atmosphere, even at a low C/H value.

  14. Water loss from Venus: Implications for the Earth's early atmosphere

    NASA Technical Reports Server (NTRS)

    Richardson, S. M.; Pollack, J. B.; Reynolds, R. T.

    1985-01-01

    The atmosphere of Venus outgassed rapidly as a result of planetary heating during accretion, resulting in massive water loss. The processes affecting atmospheric chemistry following accretion have consisted largely of hydrogen escape and internal re-equilibrium. The initial bulk composition of Venus and Earth are assumed to have been roughly similar. Chemical speciation on Venus was controlled by the temperature and oxygen buffering capacity of the surface magma. It is also assumed that the surfaces of planetary bodies of the inner solar system were partly or wholly molten during accretion with a temperature estimated at 1273 to 1573 K. To investigate the range of reasonable initial atmospheric compositions on Venus, limits have to be set for the proportion of total hydrogen and the buffered fugacity of oxygen. Using the C/H ratio of 0.033 set for Earth, virtually all of the water generated during outgassing must later have been lost in order to bring the current CO2/H2O ratio for Venus up to its observed value of 10 sup 4 to 10 sup 5. The proportion of H2O decreases in model atmospheres with successfully higher C/H values, ultimately approaching the depleted values currently observed on Venus. Increasing C/H also results in a rapid increase in CO/H2O and provides an efficient mechanism for water loss by the reaction CO+H2O = CO2 + H2. This reaction, plus water loss mechanisms involving crustal iron, could have removed a very large volume of water from the Venusian atmosphere, even at a low C/H value.

  15. Quality of surface water in Missouri, water year 2012

    USGS Publications Warehouse

    Barr, Miya N.

    2014-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2012 water year (October 1, 2011, through September 30, 2012), data were collected at 81 stations—73 Ambient Water-Quality Monitoring Network stations, 6 alternate Ambient Water-Quality Monitoring Network stations, and 2 U.S. Geological Survey National Stream Quality Accounting Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 78 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  16. Quality of surface water in Missouri, water year 2013

    USGS Publications Warehouse

    Barr, Miya N.; Schneider, Rachel E.

    2014-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2013 water year (October 1, 2012, through September 30, 2013), data were collected at 79 stations—73 Ambient Water-Quality Monitoring Network stations, 4 alternate Ambient Water-Quality Monitoring Network stations, and 2 U.S. Geological Survey National Stream Quality Accounting Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 76 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  17. New forcefield for water nanodroplet on a graphene surface

    NASA Astrophysics Data System (ADS)

    Włoch, Jerzy; Terzyk, Artur P.; Kowalczyk, Piotr

    2017-04-01

    We propose a new forcefield for water TIP4P/2005 nanodroplet sitting on a surface of a graphene. Existing in literature forcefield uses the SPC/E model. However, this model does not predict the accurate water surface tension, and in this way a contact angle (CA) can also be incorrect. Additionally, our new calibration bases on the results of long - term simulation, and on a new procedure of CA calculation, and this is crucial for the estimation of precise and equilibrium values. Finally, we discuss the new dependence of the water nanodroplet line tension on the energy of water - graphene interactions.

  18. Third Stokes parameter emission from a periodic water surface

    NASA Technical Reports Server (NTRS)

    Johnson, J. T.; Kong, J. A.; Shin, R. T.; Staelin, D. H.; Oneill, K.; Lohanick, A.

    1991-01-01

    An experiment in which the third Stokes parameter thermal emission from a periodic water surface was measured is documented. This parameter is shown to be related to the direction of periodicity of the periodic surface and to approach brightnesses of up to 30 K at X band for the surface used in the experiment. The surface actually analyzed was a 'two-layer' periodic surface; the theory of thermal emission from such a surface is derived and the theoretical results are found to be in good agreement with the experimental measurements. These results further the idea of using the third Stokes parameter emission as an indicator of wind direction over the ocean.

  19. Surface waters of Kansas, 1895-1919

    USGS Publications Warehouse

    Rice, R.C.

    1921-01-01

    The collection of long-time records of stream-flow in Kansas which is published in this volume has been prepared for the use of those who are concerned with the different phases of the utilization of water in the state.

  20. Chloride in ground water and surface water in the vicinity of selected surface-water sampling sites of the beneficial use monitoring program of Oklahoma, 2003

    USGS Publications Warehouse

    Mashburn, Shana L.; Sughru, Michael P.

    2004-01-01

    The Oklahoma Water Resources Board Beneficial Use Monitoring Program reported exceedances of beneficial-use standards for chloride at 11 surface-water sampling sites from January to October 2002. The U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study to determine the chloride concentrations in ground water in the vicinity of Beneficial Use Monitoring Program surface-water sampling sites not meeting beneficial use standards for chloride and compare chloride concentrations in ground water and surface water. The chloride-impaired Beneficial Use Monitoring Program surface-water sampling sites are located in the western and southern regions of Oklahoma. The ground-water sampling sites were placed in proximity to the 11 surface-water sampling sites designated impaired by chloride by the Oklahoma Water Resources Board. Two surface-water sampling sites were located on the Beaver River (headwaters of the North Canadian River), three sites on the Cimarron River, one site on Sandy Creek, one site on North Fork Red River, and four sites on the Red River. Six ground-water samples were collected, when possible, from two test holes located upstream from each of the 11 Beneficial Use Monitoring Program surface-water sampling sites. One test hole was placed on the left bank and right bank, when possible, of each Beneficial Use Monitoring Program surfacewater sampling site. All test holes were located on alluvial deposits adjacent to the Beneficial Use Monitoring Program surface-water sampling sites within 0.5 mile of the stream. Top, middle, and bottom ground-water samples were collected from the alluvium at each test hole, when possible. Water properties of specific conductance, pH, water temperature, and dissolved oxygen were recorded in the field before sampling for chloride. The ground-water median chloride concentrations at 8 of the 11 Beneficial Use Monitoring Program sites were less than the surface-water median

  1. Water-collecting behavior of nanostructured surfaces with special wettability

    NASA Astrophysics Data System (ADS)

    Choo, Soyoung; Choi, Hak-Jong; Lee, Heon

    2015-01-01

    Dew is commonly formed even in dry regions, and we examined the suitability of surfaces with superhydrophilic patterns on a superhydrophobic background as a dew-harvesting system. Nanostructured surfaces with mixed wettability were fabricated by ZnO and TiO2 nanorods. The condensation properties were investigated by environmental scanning electron microscopy (ESEM), and the water-collecting function of the patterned surfaces in an artificial environment was confirmed. Condensation and water-collecting behavior were evaluated as a function of surface inclination angle and pattern shape. We examined the collecting efficiency among the different wettabilities at various inclination angles and observed the condensation behavior for various superhydrophilic shapes.

  2. Anomalously Rapid Hydration Water Diffusion Dynamics Near DNA Surfaces.

    PubMed

    Franck, John M; Ding, Yuan; Stone, Katherine; Qin, Peter Z; Han, Songi

    2015-09-23

    The emerging Overhauser effect dynamic nuclear polarization (ODNP) technique measures the translational mobility of water within the vicinity (5-15 Å) of preselected sites. The work presented here expands the capabilities of the ODNP technique and illuminates an important, previously unseen, property of the translational diffusion dynamics of water at the surface of DNA duplexes. We attach nitroxide radicals (i.e., spin labels) to multiple phosphate backbone positions of DNA duplexes, allowing ODNP to measure the hydration dynamics at select positions along the DNA surface. With a novel approach to ODNP analysis, we isolate the contributions of water molecules at these sites that undergo free translational diffusion from water molecules that either loosely bind to or exchange protons with the DNA. The results reveal that a significant population of water in a localized volume adjacent to the DNA surface exhibits fast, bulk-like characteristics and moves unusually rapidly compared to water found in similar probe volumes near protein and membrane surfaces. Control studies show that the observation of these characteristics are upheld even when the DNA duplex is tethered to streptavidin or the mobility of the nitroxides is altered. This implies that, as compared to protein or lipid surfaces, it is an intrinsic feature of the DNA duplex surface that it interacts only weakly with a significant fraction of the surface hydration water network. The displacement of this translationally mobile water is energetically less costly than that of more strongly bound water by up to several kBT and thus can lower the activation barrier for interactions involving the DNA surface.

  3. Luneburg modified lens for surface water waves

    NASA Astrophysics Data System (ADS)

    Pichard, Helene; Maurel, Agnes; Petitjeans, Phillipe; Martin, Paul; Pagneux, Vincent

    2015-11-01

    It is well known that when the waves pass across an elevated bathymetry, refraction often results in amplification of waves behind it. In this sense, focusing of liquid surface waves can be used to enhance the harvest efficiency of ocean power. An ocean wave focusing lens concentrates waves on a certain focal point by transforming straight crest lens of incident waves into circular ones just like an optical lens. These devices have attracted ocean engineers and are promising because they enable the effective utilization of wave energy, the remaining challenge being to increase the harvest efficiency of the lens. In this work, in order to improve well known focusing of surface liquid waves by lens, the propagation of liquid surface waves through a Luneburg modified lens is investigated. The traditional Luneburg lens is a rotationally symmetric lens with a spatially varying refractive-index profile that focuses an incident plane wave on the rim of the lens. The modified Luneburg lens allows to choose the position of the focal point, which can lie inside or outside the lens. This new degree of freedom leads to enhanced focusing and tunable focusing. The focusing of linear surface waves through this lens is investigated and is shown to be more efficient than classical profile lenses.

  4. Identifying and Mapping Seasonal Surface Water Frost with MGS TES

    NASA Astrophysics Data System (ADS)

    Bapst, J.; Bandfield, J. L.; Wood, S. E.

    2013-12-01

    The Thermal Emission Spectrometer (TES) visible/near-infrared and thermal infrared bolometers measured surface broadband albedo and temperature for more than three Mars years. As seasons progress on Mars, surface temperatures may fall below the frost point of volatiles in the atmosphere (namely, carbon dioxide and water). Systematic mapping of the spatial and temporal occurrence of these volatiles in the martian atmosphere, on the surface, and in the subsurface has shown their importance in understanding the climate of Mars. However, few studies have investigated seasonal surface water frost and its role in the global water cycle. We examine zonally-averaged TES daytime albedo, temperature, and water vapor abundance data [after Smith, 2004] to map the presence of surface water frost on Mars. Surface water frost occurs in the polar and mid latitudes, in regions with surface temperatures less than 220 K and above 150 K, and can significantly increase albedo relative to the bare surface. In the northern hemisphere water frost is most apparent in late fall/early winter, before the onset of carbon dioxide frost. Dust storms occurring near northern winter solstice affect albedo data and prevent us from putting a latitudinal lower limit on the water frost in the northern hemisphere. Regardless, seasonal water frost occurs at least as low as 48°N in Utopia Planitia, beginning at Ls=~230°, as observed by Viking Lander 2 [Svitek and Murray, 1990]. Daytime surface water frost was also observed at the Phoenix Lander site (68°N) beginning at Ls=~160° [Cull et al., 2010]. The timing of albedo variations observed by TES agree relatively well with lander observations of seasonal frost. Seasonal water frost is not detected during fall in the southern hemisphere. A potential explanation for this discrepancy, compared with frost detections in the north, is the disparity in atmospheric water vapor abundance between the two hemispheres. The frost point temperatures for water vapor

  5. Water diffusion on TiO2 anatase surface

    NASA Astrophysics Data System (ADS)

    Agosta, L.; Gala, F.; Zollo, G.

    2015-06-01

    Compatibility between biological molecules and inorganic materials, such as crystalline metal oxides, is strongly dependent on the selectivity properties and the adhesion processes at the interface between the two systems. Among the many different aspects that affect the adsorption processes of peptides or proteins onto inorganic surfaces, such as the charge state of the amino acids, the peptide 3D structure, the surface roughness, the presence of vacancies or defects on and below the surface, a key role is certainly played by the water solvent whose molecules mediate the interaction. Then the surface hydration pattern may strongly affect the adsorption behavior of biological molecules. For the particular case of (101) anatase TiO2 surface that has a fundamental importance in the interaction of biocompatible nano-devices with biological environment, it was shown, both theoretically and experimentally, that various hydration patterns are close in energy and that the water molecules are mobile at as low temperature values as 190 K. Then it is important to understand the dynamical behavior of first hydration layer of the (101) anatase surface. As a first approach to this problem, density functional calculations are used to investigate water diffusion on the (101) anatase TiO2 surface by sampling the potential energy surface of water molecules of the first hydration layer thus calculating the water molecule migration energy along some relevant diffusion paths on the (101) surface. The measured activation energy of water migration seems in contrast with the observed surface mobility of the water molecules that, as a consequence could be explained invoking a strong role of the entropic term in the context of the transition state theory.

  6. A siphon gage for monitoring surface-water levels

    USGS Publications Warehouse

    McCobb, T.D.; LeBlanc, D.R.; Socolow, R.S.

    1999-01-01

    A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold

  7. 2H and 18O depletion of water close to organic surfaces

    NASA Astrophysics Data System (ADS)

    Chen, Guo; Auerswald, Karl; Schnyder, Hans

    2016-06-01

    Hydrophilic surfaces influence the structure of water close to them and may thus affect the isotope composition of water. Such an effect should be relevant and detectable for materials with large surface areas and low water contents. The relationship between the volumetric solid : water ratio and the isotopic fractionation between adsorbed water and unconfined water was investigated for the materials silage, hay, organic soil (litter), filter paper, cotton, casein and flour. Each of these materials was equilibrated via the gas phase with unconfined water of known isotopic composition to quantify the isotopic difference between adsorbed water and unconfined water. Across all materials, isotopic fractionation was significant (p<0.05) and negative (on average -0.91 ± 0.22 ‰ for 18/16O and -20.6 ± 2.4 ‰ for 2/1H at an average solid : water ratio of 0.9). The observed isotopic fractionation was not caused by solutes, volatiles or old water because the fractionation did not disappear for washed or oven-dried silage, the isotopic fractionation was also found in filter paper and cotton, and the fractionation was independent of the isotopic composition of the unconfined water. Isotopic fractionation became linearly more negative with increasing volumetric solid : water ratio and even exceeded -4 ‰ for 18/16O and -44 ‰ for 2/1H. This fractionation behaviour could be modelled by assuming two water layers: a thin layer that is in direct contact and influenced by the surface of the solid and a second layer of varying thickness depending on the total moisture content that is in equilibrium with the surrounding vapour. When we applied the model to soil water under grassland, the soil water extracted from 7 and 20 cm depth was significantly closer to local meteoric water than without correction for the surface effect. This study has major implications for the interpretation of the isotopic composition of water extracted from organic matter, especially when the volumetric

  8. Quality of surface water in Missouri, water year 2010

    USGS Publications Warehouse

    Barr, Miya N.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designs and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2010 water year (October 1, 2009 through September 30, 2010), data were collected at 75 stations-72 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, and 1 spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  9. Quality of surface water in Missouri, water year 2011

    USGS Publications Warehouse

    Barr, Miya N.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2011 water year (October 1, 2010, through September 30, 2011), data were collected at 75 stations—72 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, and 1 spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  10. Quality of surface water in Missouri, water year 2009

    USGS Publications Warehouse

    Barr, Miya N.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designs and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2009 water year (October 1, 2008, through September 30, 2009), data were collected at 75 stations-69 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, 1 spring sampled in cooperation with the U.S. Forest Service, and 3 stations sampled in cooperation with the Elk River Watershed Improvement Association. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and seven-day low flow is presented.

  11. Quality of surface water in Missouri, water year 2014

    USGS Publications Warehouse

    Barr, Miya N.

    2015-12-18

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2014 water year (October 1, 2013, through September 30, 2014), data were collected at 74 stations—72 Ambient Water-Quality Monitoring Network stations and 2 U.S. Geological Survey National Stream Quality Assessment Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 71 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and 7-day low flow is presented.

  12. Quality of surface water in Missouri, water year 2015

    USGS Publications Warehouse

    Barr, Miya N.; Heimann, David C.

    2016-11-14

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams and springs throughout Missouri known as the Ambient Water-Quality Monitoring Network. During water year 2015 (October 1, 2014, through September 30, 2015), data were collected at 74 stations—72 Ambient Water-Quality Monitoring Network stations and 2 U.S. Geological Survey National Stream Quality Assessment Network stations. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, Escherichia coli bacteria, fecal coliform bacteria, dissolved nitrate plus nitrite as nitrogen, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 71 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak streamflows, monthly mean streamflows, and 7-day low flows is presented.

  13. Tritium and Stable Isotopes of Precipitation and Surface Water in California

    NASA Astrophysics Data System (ADS)

    Harms, P.; Moran, J. E.; Visser, A.; Esser, B. K.

    2014-12-01

    Tritium (3H) and stable isotopes (2H and 18O) are effective natural tracers of water molecules through the hydrologic system. The strong topographic gradient in California results in distinct isotopic signatures that are particularly effective in watershed studies. Past studies of meteoric tritium distribution within the United States have focused on large-scale trends, at low spatial resolution. Globally, tritium in precipitation is monitored by the International Atomic Energy Agency contributing to the Global Network of Isotopes in Precipitation (GNIP) database. The two tritium monitoring stations in California contributing to the GNIP database were discontinued in 1976 (Santa Maria) and 1993 (Menlo Park). Surface water studies have focused on time series in major rivers nationwide or localized studies. Our study focuses on high spatial resolution water isotope data collection in California. Over 140 tritium and stable water isotope samples were collected from surface water and direct precipitation during the 2013 Summer/Fall and 2014 Winter/Spring flow regimes and analyzed by helium accumulation and noble gas mass spectrometry. Surface water samples are collected as a proxy for precipitation and to investigate trends related to water residence times. Tritium concentrations in precipitation show strong spatial trends, with higher concentrations at inland high elevation locations. Surface water tritium trends with spatial location (latitude and longitude) and elevation (reflecting the precipitation signal) and distance downstream (reflecting water residence times). A local meteoric water line (MWL) for California is developed from stable isotope data and analyzed in comparison to the global MWL. Results have implications for tritium tracer and water provenance studies.

  14. Role of water in polymer surface modification using organosilanes

    NASA Astrophysics Data System (ADS)

    Thallapalle, Pradeep Kumar; Zhang Newby, Bi-Min

    2002-03-01

    In general, polymers exhibit excellent bulk properties but may not possess specific surface properties for successful applications in biomaterials and nanotechnology. Surface modification of polymers with the self-assembled monolayers (SAMs) of organosilanes - ‘Silanization’ - is an attractive approach to alter surface properties without altering the polymer’s desired bulk properties. However, a pretreatment such as exposure to UV/O or plasma is normally required to generate active surface groups prior to silanization. These pretreatments cause undesirable surface changes such as severe surface roughening and excessive surface damage. Recent studies in silanization suggest that the presence of water or OH groups on the surface is essential to form SAMs. In this study we investigated the importance of surface water layer and OH groups in the formation of SAMs for a variety of polymers. The pre and post-modified polymers were examined using fourier transform infrared spectrometry, scanning probe microscopy and contact angle measurements. The results show that organosilanes can be grafted to a polymer surface as long as a water layer can be physisorbed to the surface or the polymer itself contains OH groups. However the monolayers formed are less organized compared to those formed on silicon wafers due to the amorphous nature of the polymers.

  15. ICESat-derived inland water surface spot heights

    NASA Astrophysics Data System (ADS)

    O'Loughlin, Fiachra E.; Neal, Jeffrey; Yamazaki, Dai; Bates, Paul D.

    2016-04-01

    Accurate measurement of water surface height is key to many fields in hydrology and limnology. Satellite radar and laser altimetry have been shown to be useful means of obtaining such data where no ground gauging stations exist, and the accuracy of different satellite instruments is now reasonably well understood. Past validation studies have shown water surface height data from the ICESat instrument to have the highest vertical accuracy (mean absolute errors of ˜10 cm for ICESat, compared, for example, with ˜28 cm from Envisat), yet no freely available source of processed ICESat data currently exists for inland water bodies. Here we present a database of processed and quality checked ICESat-derived inland water surface heights (IWSH) for water bodies greater than 3 arc sec (˜92 m at the equator) in width. Four automated methods for removing spurious observations or outliers were investigated, along with the impact of using different water masks. We find that the best performing method ensures that observations used are completely surrounded by water in the SRTM Water Body data. Using this method for removing spurious observations, we estimate transect-averaged water surface heights at 587,292 unique locations from 2003 to 2009, with the number of locations proportional to the size of the river.

  16. Nanostructured Anti-Reflecting and Water-Repellent Surface Coatings

    SciTech Connect

    2016-11-08

    A nanotechnology-based surface-texturing method developed at Brookhaven Lab’s Center for Functional Nanomaterials imparts perfect anti-reflection and robust water-repellency to silicon, glass, and some plastics.

  17. Nanostructured Anti-Reflecting and Water-Repellent Surface Coatings

    ScienceCinema

    None

    2016-11-23

    A nanotechnology-based surface-texturing method developed at Brookhaven Lab’s Center for Functional Nanomaterials imparts perfect anti-reflection and robust water-repellency to silicon, glass, and some plastics.

  18. Competitive surface enrichment of alcohols in ternary water alcohol mixtures

    NASA Astrophysics Data System (ADS)

    Raina, G.; Kulkarni, G. U.

    2003-05-01

    Molecular beams generated from the vapors above the surfaces of ternary mixtures, water-methanol-ethanol, water-ethanol-1-propanol and water-methanol-1-propanol have been examined by mass spectrometry. The propensity for surface enrichment of the alcohols is obtained in terms of the vapor mole fractions of the alcohols, which in turn were estimated from the cluster populations in the molecular beam. The enriching propensities in the ternary mixtures are compared with those in the binary mixtures. The net surface enrichment in ternary mixtures is generally lowered in comparison to that in the binary mixtures, except in the case of water-methanol-ethanol, where it is similar. While the surface enriching ability of methanol is nearly unaffected, that of ethanol is enhanced. The enriching ability of the longer chain propanol, however decreases significantly.

  19. Particles in Surface Waters: Coagulation and Transport.

    NASA Astrophysics Data System (ADS)

    Culkin, Gerald William

    Conventional water quality assessment and simulation of particles in natural waters focus on bulk concentrations of the suspended solid phase. These analyses rely directly or indirectly on a linear, 'average particle' approach to describe processes that are nonlinear and highly size -dependent. Size-dependent transport and transformation mechanisms were simulated in this research to identify conditions in which coagulation is important. Explicit finite difference schemes for two-dimensional, laterally-averaged, unsteady particle transport were developed to approximate the size -dependent particle transport processes, which included advection, dispersion, and settling. Coupled exchange of discrete particles between the water column and sediment bed was modeled using size-dependent particle sedimentation and resuspension. Simultaneous particle-particle flocculation was integrated over time in parallel with transport. Model simulations of systems with idealized morphometry and forcing provided greater insight to competing processes that drive particle behavior in natural systems. Application of the model to a real system gave plausible results and suggested explanations for observed conditions.

  20. Water evaporation from substrate tooth surface during dentin treatments.

    PubMed

    Kusunoki, Mizuho; Itoh, Kazuo; Gokan, Yuka; Nagai, Yoshitaka; Tani, Chihiro; Hisamitsu, Hisashi

    2011-01-01

    The purpose of this study was to evaluate changes in the quantity of water evaporation from tooth surfaces. The amount of water evaporation was measured using Multi probe adapter MPA5 and Tewameter TM300 (Courage+Khazaka Electric GmbH, Köln, Germany) after acid etching and GM priming of enamel; and after EDTA conditioning and GM priming of dentin. The results indicated that the amount of water evaporation from the enamel surface was significantly less than that from the dentin. Acid etching did not affect the water evaporation from enamel, though GM priming significantly decreased the evaporation (83.48 ± 15.14% of that before priming). The evaporation from dentin was significantly increased by EDTA conditioning (131.38 ± 42.08% of that before conditioning) and significantly reduced by GM priming (80.26 ± 7.43% of that before priming). It was concluded that dentin priming reduced water evaporation from the dentin surface.

  1. The biological impact of landfill leachate on nearby surface water

    SciTech Connect

    Geis, S.W.

    1994-12-31

    Five landfill sites were evaluated for their potential to adversely impact the biotic community of surface waters. Acute and chronic aquatic toxicity tests were used to determine the toxicity of water samples collected from landfill monitoring wells and the nearest surface water. Four of the five landfill sites exhibited acute or chronic toxicity to Ceriodaphnia dubia, Daphnia magna, or Pimephales promelas. Toxicity identification procedures performed on water samples revealed toxic responses to metals and one toxic response to organic compounds. Surface water toxicity at an industrial landfill is most likely due to zinc from a tire production facility. Iron and a surfactant were determined to be the probable causes for toxicity at two municipal solid waste landfills.

  2. Shallow Water Propagation and Surface Reverberation Modeling

    DTIC Science & Technology

    2013-09-30

    original goals have been augmented in 2013 to study ambient noise from glaciers in high latitude regions. OBJECTIVES Objectives for 2013 The overall...to deduce the form of surfaces from scattered sound and (2) to measure and analyze the underwater ambient noise marine terminating glaciers in high...particularly those that contain the terminus of one or more glaciers . The program objective was to measure the directionality of underwater ambient

  3. Shallow Water Propagation and Surface Reverberation Modeling

    DTIC Science & Technology

    2012-09-30

    compare the results with experiment. This work will be used to help interpret field data of bistatic scattering from sea ice cover and calibrate...approximate analytical and numerical acoustic models used to compute bistatic scattering. The clouds of bubbles entrained at the sea surface by breaking...ABSTRACT SAR 18. NUMBER OF PAGES 7 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b. ABSTRACT unclassified c. THIS PAGE unclassified

  4. Endocrine disruptors and pharmaceuticals: implications for water sustainability.

    PubMed

    Snyder, Shane A; Benotti, Mark J

    2010-01-01

    The presence of pharmaceuticals and endocrine disrupting compounds (EDCs) in the environment raises many questions about risk to the environment and risk to human health. Researchers have attributed adverse ecological effect effects to the presence of these compounds, particularly EDCs, though there is no consensus on what risk, if any, these compounds pose to human health. The scientific community is in the process of developing a better understanding of the occurrence, fate, and transport of pharmaceuticals and EDCs in the environment, including a better characterization of human exposure via drinking water. This paper provides a brief review of pharmaceuticals and EDCs in drinking water, as well as uses examples from Lake Mead, Nevada, USA, to highlight the issues associated with their fate and transport. Lastly, the effects of natural or anthropogenically driven processes, like natural seasonal flow or climate-change/prolonged drought are discussed as they are factors which can drastically alter environmental concentrations of these compounds. Without question, the propensity for the contamination of fresh water will rise as (1) human population continues to grow or (2) patterns of natural surface water slow and wastewater becomes a larger fraction of flow further highlighting the need for a more comprehensive understanding of their environmental behavior.

  5. Tracer injection techniques in flowing surface water

    NASA Astrophysics Data System (ADS)

    Wörman, A.

    2009-04-01

    Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed

  6. Intermolecular Casimir-Polder forces in water and near surfaces.

    PubMed

    Thiyam, Priyadarshini; Persson, Clas; Sernelius, Bo E; Parsons, Drew F; Malthe-Sørenssen, Anders; Boström, Mathias

    2014-09-01

    The Casimir-Polder force is an important long-range interaction involved in adsorption and desorption of molecules in fluids. We explore Casimir-Polder interactions between methane molecules in water, and between a molecule in water near SiO(2) and hexane surfaces. Inclusion of the finite molecular size in the expression for the Casimir-Polder energy leads to estimates of the dispersion contribution to the binding energies between molecules and between one molecule and a planar surface.

  7. Surface water connectivity dynamics of a large scale extreme flood

    NASA Astrophysics Data System (ADS)

    Trigg, Mark A.; Michaelides, Katerina; Neal, Jeffrey C.; Bates, Paul D.

    2013-11-01

    Uses the MODIS surface water product observations of the 2011 Bangkok flood.A data gap filling method is developed to better preserve the dynamics of the event.We quantify surface water connectivity geostatistically to give new flood insights.There is a clear structure to the connectivity of the event through time and space.Changes and thresholds in the connectivity are linked to major flood mechanisms.

  8. Miscellaneous surface-water data, Pecos River basin, New Mexico

    USGS Publications Warehouse

    Cranston, C. Clare; Kues, Georgianna E.; Welder, G.E.

    1981-01-01

    Miscellaneous surface-water data from the Pecos River basin of New Mexico are assembled into one table. Measurements and estimates of the discharge of streams, springs, and diversion canals and pumps that are not readily available to the public are given. The principal sources of information are published and unpublished reports and various records of the U.S. Geological Survey and the New Mexico State Engineer Office. Many thousands of surface-water discharge values are given. (USGS)

  9. Geomorphological control of water tables in a blanket peat landscape: implications for carbon cycling

    NASA Astrophysics Data System (ADS)

    Allott, Tim; Evans, Martin; Lindsay, John; Agnew, Clive; Freer, Jim

    2010-05-01

    than intact sites. This site-scale effect is hypothesised to result from reduced hydrological contributing areas (drainage areas) at eroded sites, with hillslope drainage diverted into gully channels. Distinct patterns of temporal water table behaviour are apparent between intact and heavily eroded locations. At intact locations water tables are predominantly close to the ground surface, except during periods of dry weather when a pattern of gradual water table drawdown occurs. Water tables rise rapidly following rainfall. This behaviour is characteristic of intact blanket peats in other regions. Water table behaviour at heavily eroded locations is very different, characterised by predominantly low water table conditions with ‘wet-up' responses to rainfall, i.e. very rapid rises in water table followed immediately by rapid drain-down after the cessation of rainfall. These spatio-temporal patterns in water tables conditions demonstrate the very different hydrological behaviours of eroded and intact peats. In this eroded peatland landscape there is strong geomorphological control on water table conditions. Implications for both the hydrological functioning of the peatland and the carbon cycle are discussed.

  10. Spatial and temporal assessment of surface water quality in the Arka River, Akkar, Lebanon.

    PubMed

    Daou, Claude; Nabbout, Rony; Kassouf, Amine

    2016-12-01

    Surface water quality monitoring constitutes a crucial and important step in any water quality management system. Twenty-three physicochemical and microbiological parameters were assessed in surface water samples collected from the Arka River located in the Akkar District, north of Lebanon. Eight sampling locations were considered along the river and seven sampling campaigns were performed in order to evaluate spatial and temporal influences. The extraction of relevant information from this relatively large data set was done using principal component analysis (PCA), being a very well established chemometric tool in this field. In a first step, extracted PCA loadings revealed the implication of several physicochemical parameters in the discriminations and trends highlighted by PCA scores, mainly due to soil leaching and seawater intrusion. However, further investigations showed the implication of organic and bacterial parameters in the discrimination of stations in the Akkar flatland. These discriminations probably refer to anthropogenic pollution coming from the agricultural area and the surrounding villages. Specific ultraviolet absorption (SUVA) indices confirmed these findings since values decreased for samples collected across the villages and the flatland, indicating an increase in anthropogenic dissolved organic matter. This study will hopefully help the national and local authorities to ameliorate the surface water quality management, enabling its proper use for irrigation purposes.

  11. Tide-induced surface water and groundwater interactions in coastal wetlands

    NASA Astrophysics Data System (ADS)

    Xin, P.; Kong, J.; Li, L.; Barry, D. A.

    2011-12-01

    Intertidal wetlands such as salt marshes are complex hydrological systems characterized by strong, dynamic interactions between coastal surface water and groundwater, driven particularly by tides. We simulated such interactions with a focus on 3D, variably saturated pore water flow in a salt marsh with a two-layer soil configuration (with a low-permeability mud layer overlying a high-permeability sandy-loam layer), which is commonly found in natural marshes. Simulated intra-tidal groundwater dynamics exhibited significant flow asymmetry with non-zero mean flow velocities over the tidal period. The tidally averaged flow led to 3D pore water circulation linked strongly to the marsh topography, over a range of spatial scales: near the creek bank, around the creek meander and over long marsh sections inclined towards the main channel. Time scales associated with these circulations differed by orders of magnitude. Under the simulated conditions, the creek served as the main outlet of the pore water circulation paths, especially those with infiltration taking place in the upper marsh surface areas away from the main channel. Water infiltrating the soil in the lower marsh surface areas away from the creek tended to discharge to the main channel directly. These flow characteristics have important implications for mass and nutrient transport and transformations in the marsh soil. Since the origin of pore water in the marsh soil is largely the coastal surface water, the travel paths and times revealed by the particle tracking are key factors that determine the (modified) chemical composition of the recycling water at the circulation outlet, which in turn affects the net exchange between the marsh and coastal surface water. Our study highlights the hydrological complexity of intertidal marshes and the need for further research on interactions among marsh morphology, hydrology and ecology, which underpin the functionalities of these wetland systems.

  12. Safety implications of a large LNG tanker spill over water.

    SciTech Connect

    Hightower, Marion Michael; Gritzo, Louis Alan; Luketa-Hanlin, Anay Josephine

    2005-04-01

    The increasing demand for natural gas in the United States could significantly increase the number and frequency of marine LNG (liquefied natural gas) imports. Although many studies have been conducted to assess the consequences and risks of potential LNG spills, the increasing importance of LNG imports suggests that consistent methods and approaches be identified and implemented to help ensure protection of public safety and property from a potential LNG spill. For that reason the U.S. Department of Energy (DOE), Office of Fossil Energy, requested that Sandia National Laboratories (Sandia) develop guidance on a risk-based analysis approach to assess and quantify potential threats to an LNG ship, the potential hazards and consequences of a large spill from an LNG ship, and review prevention and mitigation strategies that could be implemented to reduce both the potential and the risks of an LNG spill over water. Specifically, DOE requested: (1) An in-depth literature search of the experimental and technical studies associated with evaluating the safety and hazards of an LNG spill from an LNG ship; (2) A detailed review of four recent spill modeling studies related to the safety implications of a large-scale LNG spill over water; (3) Evaluation of the potential for breaching an LNG ship cargo tank, both accidentally and intentionally, identification of the potential for such breaches and the potential size of an LNG spill for each breach scenario, and an assessment of the potential range of hazards involved in an LNG spill; (4) Development of guidance on the use of modern, performance-based, risk management approaches to analyze and manage the threats, hazards, and consequences of an LNG spill over water to reduce the overall risks of an LNG spill to levels that are protective of public safety and property.

  13. Chlorine stress mediates microbial surface attachment in drinking water systems.

    PubMed

    Liu, Li; Le, Yang; Jin, Juliang; Zhou, Yuliang; Chen, Guowei

    2015-03-01

    Microbial attachment to drinking water pipe surfaces facilitates pathogen survival and deteriorates disinfection performance, directly threatening the safety of drinking water. Notwithstanding that the formation of biofilm has been studied for decades, the underlying mechanisms for the origins of microbial surface attachment in biofilm development in drinking water pipelines remain largely elusive. We combined experimental and mathematical methods to investigate the role of environmental stress-mediated cell motility on microbial surface attachment in chlorination-stressed drinking water distribution systems. Results show that at low levels of disinfectant (0.0-1.0 mg/L), the presence of chlorine promotes initiation of microbial surface attachment, while higher amounts of disinfectant (>1.0 mg/L) inhibit microbial attachment. The proposed mathematical model further demonstrates that chlorination stress (0.0-5.0 mg/L)-mediated microbial cell motility regulates the frequency of cell-wall collision and thereby controls initial microbial surface attachment. The results reveal that transport processes and decay patterns of chlorine in drinking water pipelines regulate microbial cell motility and, thus, control initial surface cell attachment. It provides a mechanistic understanding of microbial attachment shaped by environmental disinfection stress and leads to new insights into microbial safety protocols in water distribution systems.

  14. Occurrence of deeethylatrazine and deisopropylatrazine in surface and ground water

    SciTech Connect

    Thurman, E.M.; Goolsby, D.A.

    1996-10-01

    Field-disappearance studies and a regional study of nine rivers in the Midwest show that deethylatrazine (DEA) and deisopropylatrazine (DIA) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine and cyanazine. The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 mg/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations giving a {open_quotes}second flush{close_quotes} of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4{plus_minus}0.1 when atrazine is the major triazine present to 0.6{plus_minus}0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

  15. Landfill disposal of unused medicines reduces surface water releases.

    PubMed

    Tischler, Lial; Buzby, Mary; Finan, Douglas S; Cunningham, Virginia L

    2013-01-01

    The pharmaceutical industry is conducting research to evaluate the pathways and fate of active pharmaceutical ingredients from the consumer to surface waters. One potential pathway identified by the researchers is the disposal of unused pharmaceutical products that are discarded by consumers in household trash and disposed of in municipal solid waste landfills. This study was designed to evaluate relative amounts of surface water exposures through the landfill disposal pathway compared to patient use and flushing of unused medicine pathways. The estimated releases to surface water of 24 example active pharmaceutical ingredients (APIs) in landfill leachate were calculated for 3 assumed disposal scenarios: 5%, 10%, and 15% of the total annual quantity of API sold is discarded and unused. The estimated releases from landfills to surface waters, after treatment of the leachate, were compared to the total amount of each example API that would be released to surface waters from publicly owned treatment works, generated by patient use and excretion. This study indicates that the disposal of unused medications in municipal solid waste landfills effectively eliminates the unused medicine contribution of APIs to surface waters; greater than 99.9% of APIs disposed of in a landfill are permanently retained.

  16. Formation and transport of deethylatrazine and deisopropylatrazine in surface water

    USGS Publications Warehouse

    Thurman, E.M.; Meyer, M.T.; Mills, M.S.; Zimmerman, L.R.; Perry, C.A.; Goolsby, D.A.

    1994-01-01

    Field disappearance studies and a regional study of nine rivers in the Midwest Corn Belt show that deethylatrazine (DEA; 2-amino-4-chloro-6-isopropylamino-s-triazine) and deisopropylatrazine (DIA; 2-amino-4-chloro-6-ethylaminos-triazine) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 ??g/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations, giving a "second flush?? of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4 ?? 0.1 when atrazine is the major triazine present to 0.6 ?? 0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

  17. Modeling Studies of Geothermal Systems with a Free Water Surface

    SciTech Connect

    Bodvarsson, Gudmundur S.; Pruess, K.

    1983-12-15

    Numerical simulators developed for geothermal reservoir engineering applications generally only consider systems which are saturated with liquid water and/or steam. However, most geothermal fields are in hydraulic communicatino with shallow ground water aquifers having free surface (water level), so that production or injection operations will cause movement of the surface, and of the air in the pore spaces above the water level. In some geothermal fields the water level is located hundreds of meters below the surface (e.g. Olkaria, Kenya; Bjornsson, 1978), so that an extensive so that an extensive unsaturated zone is present. In other the caprock may be very leaky or nonexistent [e.g., Klamath Falls, oregon (Sammel, 1976)]; Cerro Prieto, Mexico; (Grant et al., 1984) in which case ther eis good hydraulic communication between the geothermal reservoir and the shallow unconfined aquifers. Thus, there is a need to explore the effect of shallow free-surface aquifers on reservoir behavior during production or injection operations. In a free-surface aquifer the water table moves depending upon the rate of recharge or discharge. This results in a high overall storativity; typically two orders of magnitude higher than that of compressed liquid systems, but one or two orders of magnitude lower than that for liquid-steam reservoirs. As a consequence, various data analysis methods developed for compressed liquid aquifers (such as conventional well test analysis methods) are not applicable to aquifer with a free surface.

  18. Quality of Surface Water in Missouri, Water Year 2008

    USGS Publications Warehouse

    Otero-Benitez, William; Davis, Jerri V.

    2009-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designed and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2008 water year (October 1, 2007, through September 30, 2008), data were collected at 67 stations, including two U.S. Geological Survey National Stream Quality Accounting Network stations and one spring sampled in cooperation with the U.S. Forest Service. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and selected pesticide data summaries are presented for 64 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and seven-day low flow is presented.

  19. Partitioning of copper to suspended particles in surface water

    SciTech Connect

    Grassi, M.T.; Shi, B.; Allen, H.E.

    1995-12-31

    The recent recommendation that Water Quality Criteria for metals be implemented based on dissolved, rather than total recoverable metal, requires significant new understanding of the role of particulate matter in surface waters. Principal factors controlling the distribution of metal between the particles and the water include suspended solids concentration, the solution pH, and the concentrations of dissolved and particulate organic carbon. The authors have investigated these variables in the laboratory to develop predictions of partitioning in natural waters. Particulate water was concentrated from the Delaware River. The binding of copper was studied as a function of solution pH. Both inorganic copper and copper contained in sewage effluent was added.

  20. Assessment of seasonal variations in surface water quality.

    PubMed

    Ouyang, Y; Nkedi-Kizza, P; Wu, Q T; Shinde, D; Huang, C H

    2006-12-01

    Assessment of seasonal changes in surface water quality is an important aspect for evaluating temporal variations of river pollution due to natural or anthropogenic inputs of point and non-point sources. In this study, surface water quality data for 16 physical and chemical parameters collected from 22 monitoring stations in a river during the years from 1998 to 2001 were analyzed. The principal component analysis technique was employed to evaluate the seasonal correlations of water quality parameters, while the principal factor analysis technique was used to extract the parameters that are most important in assessing seasonal variations of river water quality. Analysis shows that a parameter that is most important in contributing to water quality variation for one season may not be important for another season except for DOC and electrical conductance, which were always the most important parameters in contributing to water quality variations for all four seasons.

  1. Fundamental Interactions of Water with Solid Surfaces

    DTIC Science & Technology

    1990-07-20

    of Surface General Motors Research Labs Solvation Effects in Electrochemistry" 11:30 a.m. Discussion 12:30 a.m. Lunch Evening Session: Interaction of...Chemical Dept. Cu(11l0 and Pt(111): the Formation General Motors Research Labs of H 30 ?" 30500 Mound Road Warren, MI 48090-9055 Prof. J. Michael White...07974 Montreal, Oueoec H3C 3S7 CANADA Fisher. Gaien Bry 301 General Motors Research Laos. Physica) Chemistry Dept 30500 Mound Road Warren. 1-1• ý 4H1. 9

  2. Dynamics of ice nucleation on water repellent surfaces.

    PubMed

    Alizadeh, Azar; Yamada, Masako; Li, Ri; Shang, Wen; Otta, Shourya; Zhong, Sheng; Ge, Liehui; Dhinojwala, Ali; Conway, Ken R; Bahadur, Vaibhav; Vinciquerra, A Joseph; Stephens, Brian; Blohm, Margaret L

    2012-02-14

    Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.

  3. Ground-Water Age and its Water-Management Implications, Cook Inlet Basin, Alaska

    USGS Publications Warehouse

    Glass, Roy L.

    2002-01-01

    The Cook Inlet Basin encompasses 39,325 square miles in south-central Alaska. Approximately 350,000 people, more than half of Alaska?s population, reside in the basin, mostly in the Anchorage area. However, rapid growth is occurring in the Matanuska?Susitna and Kenai Peninsula Boroughs to the north and south of Anchorage. Ground-water resources provide about one-third of the water used for domestic, commercial and industrial purposes in the Anchorage metropolitan area and are the sole sources of water for industries and residents outside Anchorage. In 1997, a study of the Cook Inlet Basin was begun as part of the U.S. Geological Survey?s National Water-Quality Assessment Program. Samples of ground water were collected from 35 existing wells in unconsolidated glacial and alluvial aquifers during 1999 to determine the regional quality of ground water beneath about 790 mi2 of developed land and to gain a better understanding of the natural and human factors that affect the water quality (Glass, 2001). Of the 35 wells sampled, 31 had water analyzed for atmospherically derived substances to determine the ground water?s travel time from its point of recharge to its point of use or discharge?also known as ground-water age. Ground water moves slowly from its point of recharge to its point of use or discharge. This water starts as rain and melting snow that soak into the ground as recharge. In the Matanuska?Susitna, Anchorage, and Kenai Peninsula areas, ground water generally moves from near the mountain fronts toward Cook Inlet or the major rivers. Much of the water pumped by domestic and public-supply wells may have traveled less than 10 miles, and the trip may have taken as short a time as a few days or as long as several decades. This ground water is vulnerable to contamination from the land surface, and many contaminants in the water would follow the same paths and have similar travel times from recharge areas to points of use as the chemical substances analyzed in

  4. Glutinous Water. Protecting Vertical and Overhead Surfaces from Fire Spread

    DTIC Science & Technology

    1994-02-28

    DISTRIBUTION CODE Approved for public release; distribution unlimited. 13. ABSTRACT (Maximum 200 words ) Most of the water used in firefighting is not only...Naval Research Laboratory AD-A277 280 Washington, DC 20375-5320 NRL/MR/6180--94-7431 DTIC S ELECTE MAR 24 19941 Glutinous Water F Protecting Vertical...TYPE AND DATES COVERED February 28, 1994 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS Glutinous Water Protecting Vertical and Overhead Surfaces From Fire

  5. Surface Water Quality Investigation of the Richland Creek, Illinois Basin.

    DTIC Science & Technology

    1980-07-01

    ground water . Depending upon the form of the actual discharge, leachate and surface runoff can be either a point source of pollution or a non-point... source . The polluting characteristics of leachate and runoff are primarily a function of the waste composition, the amount of infiltrating water , and...DISCHARGES*LC - MUNICIPALIT’IES MILES FIGURE 2-3 POINT SOURCE DISCIA R GES-RI CH LAND CREEK BASIN 2-17 A general characterization of affected water

  6. An Ontology Design Pattern for Surface Water Features

    SciTech Connect

    Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E; Feng, Chen-Chieh; Usery, Lynn; Liebermann, Joshua; Sorokine, Alexandre

    2014-01-01

    Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities can be found due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology. It can then be used to systematically incor-porate concepts that are specific to a culture, language, or scientific domain. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex surface water ontologies. A fundamental distinction is made in this on-tology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is imple-mented in OWL, but Description Logic axioms and a detailed explanation is provided. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. A discussion about why there is a need to complement the pattern with other ontologies, es-pecially the previously developed Surface Network pattern is also provided. Fi-nally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through a few queries and annotated geospatial datasets.

  7. Effects of Dimethyl Sulfoxide on Surface Water near Phospholipid Bilayers

    NASA Astrophysics Data System (ADS)

    Lee, Yuno; Pincus, Philip A.; Hyeon, Changbong

    2016-12-01

    Despite much effort to probe the properties of dimethyl sulfoxide (DMSO) solution, effects of DMSO on water, especially near plasma membrane surfaces still remain elusive. By performing molecular dynamics (MD) simulations at varying DMSO concentrations ($X_{\\text{DMSO}}$), we study how DMSO affects structural and dynamical properties of water in the vicinity of phospholipid bilayers. As proposed by a number of experiments, our simulations confirm that DMSO induces dehydration from bilayer surfaces and disrupts the H-bond structure of water. However, DMSO enhanced water diffusivity at solvent-bilayer interfaces, an intriguing discovery reported by a spin-label measurement, is not confirmed in our simulations. In order to resolve this discrepancy, we examine the location of the spin-label (Tempo), relative to the solvent-bilayer interface. In accord with the evidence in the literature, our simulations, which explicitly model Tempo-PC, find that the Tempo moiety is equilibrated at $\\sim 8-10$ \\AA\\ \\emph{below} the bilayer surface. Furthermore, the DMSO-enhanced surface water diffusion is confirmed only when water diffusion is analyzed around the Tempo moiety that is immersed below the bilayer surface, which implies that the experimentally detected signal of water using Tempo stems from the interior of bilayers, not from the interface. Our analysis finds that the increase of water diffusion below the bilayer surface is coupled to the increase of area per lipid with an increasing $X_{\\text{DMSO}}$ $(\\lesssim 10\\text{ mol\\%})$. Underscoring the hydrophobic nature of Tempo moiety, our study calls for careful re-evaluation of the use of Tempo in the measurement on lipid bilayer surfaces.

  8. Effects of Dimethyl Sulfoxide on Surface Water near Phospholipid Bilayers.

    PubMed

    Lee, Yuno; Pincus, Philip A; Hyeon, Changbong

    2016-12-06

    Despite much effort to probe the properties of dimethyl sulfoxide (DMSO) solution, the effects of DMSO on water, especially near plasma membrane surfaces, still remain elusive. By performing molecular dynamics simulations at varying DMSO concentrations (XDMSO), we study how DMSO affects structural and dynamical properties of water in the vicinity of phospholipid bilayers. As proposed by a number of experiments, our simulations confirm that DMSO induces dehydration from bilayer surfaces and disrupts the H-bond structure of water. However, DMSO-enhanced water diffusivity at solvent-bilayer interfaces, an intriguing discovery reported by a spin-label measurement, is not confirmed in our simulations. To resolve this discrepancy, we examine the location of the spin label (Tempo) relative to the solvent-bilayer interface. In accord with the evidence in the literature, our simulations, which explicitly model Tempo-phosphatidylcholine, find that the Tempo moiety is equilibrated at ∼8-10 Å below the bilayer surface. Furthermore, the DMSO-enhanced surface-water diffusion is confirmed only when water diffusion is analyzed around the Tempo moiety that is immersed below the bilayer surface, which implies that the experimentally detected signal of water using Tempo stems from the interior of bilayers, not from the interface. Our analysis finds that the increase of water diffusion below the bilayer surface is coupled to the increase of area per lipid with an increasing XDMSO(≲10mol%). Underscoring the hydrophobic nature of the Tempo moiety, our study calls for careful re-evaluation of the use of Tempo in measurements on lipid bilayer surfaces. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Martian surface/near-surface water inventory: Sources, sinks, and changes with time

    NASA Astrophysics Data System (ADS)

    Carr, M. H.; Head, J. W.

    2015-02-01

    Today, a 34 m global equivalent water layer (GEL) lies in the Martian polar-layered deposits and shallow ground ice. During the Amazonian, 3 m was outgassed, and 31 m was lost to space and to the surface, leaving 62 m at the end of Hesperian. During the Hesperian, volcanic outgassing added 5 m, 7 m was lost, and 40 m GEL of groundwater was added to form outflow channels, leaving 24 m carryover of surface water from the Noachian into the Hesperian. The Hesperian budget is incompatible with a northern ocean during this era. These figures are for near-surface water; substantial amounts of water may have existed as deep ground ice and groundwater. Our estimate of approximately 24 m near-surface water in the Late Noachian is insufficient to support an ocean at that time also and favors episodic melting of an icy highlands to produce the fluvial and lacustrine features.

  10. Rapid surface-water volume estimations in beaver ponds

    NASA Astrophysics Data System (ADS)

    Karran, Daniel J.; Westbrook, Cherie J.; Wheaton, Joseph M.; Johnston, Carol A.; Bedard-Haughn, Angela

    2017-02-01

    Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume-area-depth (V-A-h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

  11. Probing the water on chemically heterogeneous surface: interfacial-structural analysis for surface charge distribution

    NASA Astrophysics Data System (ADS)

    Shin, Sucheol; Willard, Adam

    We introduce the novel method for predicting the charge distribution of chemically heterogeneous surface, but reconstructed from the perspective of the interfacial water molecules. Our approach is to analyze the response of water to a disordered surface and infer from that response the heterogeneous distribution of surface charge. We accomplish this using a framework that is based on a probabilistic description of water's interfacial molecular structure and maximum likelihood estimation. This framework allows to deduce the apparent charge that is most congruently represented by the set of water configurations over the particular region of a surface. We demonstrate that the estimated charge distribution is consistent to the actual distribution for a static model substrate and hence that our method can be applied to investigate a dynamic fluctuating substrate such as the surface of a hydrated protein. This novel technique provides the useful information that can reflect the influence of fluctuations in the structure of biomolecule.

  12. Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes

    NASA Astrophysics Data System (ADS)

    Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

    2006-12-01

    The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or

  13. Nonzero Ideal Gas Contribution to the Surface Tension of Water.

    PubMed

    Sega, Marcello; Fábián, Balázs; Jedlovszky, Pál

    2017-06-15

    Surface tension, the tendency of fluid interfaces to behave elastically and minimize their surface, is routinely calculated as the difference between the lateral and normal components of the pressure or, invoking isotropy in momentum space, of the virial tensor. Here we show that the anisotropy of the kinetic energy tensor close to a liquid-vapor interface can be responsible for a large part of its surface tension (about 15% for water, independent from temperature).

  14. Organic and inorganic species in produced water: Implications for water reuse

    USGS Publications Warehouse

    Kharaka, Yousif K.; Rice, Cynthia A.

    2004-01-01

    Currently 20-30 billion barrels of formation water are co-produced annually in the USA with conventional oil and natural gas. The large database on the geochemistry of this produced water shows salinities that vary widely from ~5,000 to >350,000 mg/L TDS. Chloride, Na and Ca are generally the dominant ions, and concentrations of Fe, Mn, B, NH3 and dissolved organics, including, BTEX, phenols and poly aromatic hydrocarbons (PAHs) may be relatively high. Hazardous concentrations of NORMs, including Ra-226 and Rn-222 have been reported in produced water from several states.Coal-bed methane (CBM) wells currently produce close to a billion barrels of water and deliver ~8% of total natural gas. The salinity of this produced water generally is lower than that of water from petroleum wells; salinity commonly is 1,000-20,000 mg/L, but ranges to150,000 mg/L TDS. Most CBM wells produce Na-HCO3-Cl type water that is low in trace metals and has no reported NORMs. This water commonly has no oil and grease and has relatively low DOC, but its organic composition has not been characterized in detail. The water is disposed of by injection into saline aquifers, through evaporation and/or percolation in disposal pits, road spreading, and surface discharge. Water that has an acceptable salinity and sodium absorption ratio (SAR) is considered acceptable for surface discharge and for injection into freshwater aquifers.As an alternative to costly disposal, low salinity produced water is being considered for reclamation, especially in the arid western USA. The cost of reclaiming this water to meet irrigation, industrial and drinking water standards was evaluated in a 10 gpm pilot field study at Placerita oil field, California. This produced water had a low salinity of ~8,000 mg/L, but high concentration of Si and organics. Removal of B, Si, NH3 and especially organics from this water proved difficult, and the estimated treatment cost was high at $0.08-$0.39/bbl for water treated for

  15. Metropolitan Spokane Region Water Resources Study. Appendix A. Surface Water

    DTIC Science & Technology

    1976-01-01

    the river as surface supply. This second area lies mostly north of the Spokane River extending up the val- ley known as Rathdrum Prairie and includes...4 10. 2-29 I .~ -A- IvA -4 -4 IS I rp4r 1-4 - 4NCs 4~ 10. 2- 3o * r~tar gg~wr 4 . fAPPENDIX I en00 -4 - r., 0 CM- WMC q ~~0 0r0 4. .44 . VFog 4102A3

  16. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

    NASA Astrophysics Data System (ADS)

    Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

    2013-10-01

    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

  17. Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces.

    PubMed

    Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

    2013-10-23

    Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

  18. Experimental Observation of Dark Solitons on Water Surface

    DTIC Science & Technology

    2016-06-13

    Experimental observation of dark solitons on water surface A. Chabchoub1,∗, O. Kimmoun2, H. Branger3, N. Hoffmann1, D. Proment4, M. Onorato4,5, and N... observation of dark solitons on the water surface. It takes the form of an amplitude drop of the carrier wave which does not change shape in propagation...type of nonlinear waves previ- ously studied in optics and plasma physics which until now has not been observed in the case of water waves. As a result

  19. Asphaltene surface activity at oil/water interfaces

    SciTech Connect

    Sheu, E.Y.; Shields, M.B.

    1995-11-01

    Small angle neutron scattering (SANS) dynamic surface tension (DST), dynamic interfacial tension (DIFT), and zero shear viscosity were used to study the surface activity of Ratawi asphaltenes in organic solvents, in the asphaltene/water/toluene emulsions and at the toluene/aqueous solution interfaces. In organic solvents, the kinetic process of micellization and the micellar structure are characterized. Their dependence on asphaltene concentration was investigated. The emulsion droplet structure and their capability in water uptake was tested. Also, the enhancement of surface activity of asphaltenes and its potential applications are briefly discussed.

  20. Effects of drainage and water table control on groundwater and surface water quality

    SciTech Connect

    Chescheir, G.M.; Skaggs, R.W.; Gilliam, J.W.; Breve, M.A.; Munster, C.

    1995-12-31

    The objectives of the research project were to: conduct field experiments to measure and evaluate the effects of drainage, controlled drainage, and subirrigation of the following hydrologic and water quality variables: Movement and fate of fertilizer nutrients and sediment in surface runoff, shallow groundwater and subsurface drainage waters; and loss of pesticides in surface and subsurface drainage waters and their movement into shallow groundwaters; test the reliability of selected models for predicting the movement of pesticides and fertilizer nutrients to shallow groundwater and the losses of these pollutants via surface and subsurface drainage waters; and modify and further develop these existing models to improve their reliability.

  1. Rupture and dewetting of water films on solid surfaces.

    PubMed

    Mulji, Neil; Chandra, Sanjeev

    2010-12-01

    An experimental study was conducted to observe rupture and dewetting of water films, 0.5-2mm thick, on solid surfaces. The effects of surface roughness, wettability, protrusions on surfaces, and air entrapment between films and surfaces were studied. Film thickness measurements were made and film rupture and surface dewetting photographed. Experiments showed that liquid films ruptured first along the highest edges of test surfaces. Placing a protrusion on the surface had no effect-the liquid film continued to rupture along the edges. A thermodynamic model was developed to show that protrusions lower the surface energy of the system and promote wetting. Increasing surface roughness therefore increases film stability by resisting rupture and dewetting. Water films could be punctured by introducing an air bubble that burst and created a hole. The hole would close if the film was thick and the solid-liquid contact angle was either small or large; the hole would grow larger if the film was thin and the contact angle was in the mid-range (∼80°). An analytical model that calculates the difference between the surface energies of the two states can be used to predict whether a hole would lead to surface dewetting or not. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Estimation of surface runoff and water-covered area during filling of surface microrelief depressions

    NASA Astrophysics Data System (ADS)

    Hansen, B.

    2000-05-01

    During the filling of surface microrelief depressions the precipitation excess (precipitation minus infiltration and interception) is divided between surface storage and runoff, i.e. runoff starts before the surface depressions are filled. Information on the division of precipitation excess is needed for modelling surface runoff during the filling of surface depressions. Furthermore, information on the surface of the area covered with water is needed for calculating infiltration of water stored in soil surface depressions. Thirty-two soil surface microreliefs were determined in Danish erosion study plots. The slope was c. 10% for all plots. Data were treated initially by removing the slope, after which 20 artificial slopes (1-20%) were introduced producing 640 new data sets. Runoff during filling of the microrelief storage was calculated for each of the 640 data sets using a model developed for calculating surface storage and runoff from grid elevation measurements. Runoff started immediately after the first addition of water for all data sets. On a field scale, however, runoff has to travel some distance as overland flow and storage in smaller and larger depressions below the runoff initiation point must be taken into consideration. The runoff increases by intermittent steps. Whenever a depression starts to overflow to the border of the plot, the runoff jumps accordingly. In spite of the jumps, the distribution between surface storage and runoff was closely related to the quotient between precipitation excess and depression storage capacity. Surface area covered with water was exponentially related to the amount of water stored in surface depressions. Models for calculating surface storage and runoff from grid elevation measurements are cumbersome and require time-consuming measurements of the soil surface microrelief. Therefore, estimation from roughness indices requiring fewer measurements is desirable. New improved equations for such estimations are suggested.

  3. Cumulative hydrologic impact assessment of coal surface mining in north Georgia - surface water

    SciTech Connect

    Poe, M.L.; Betson, R.P.

    1983-10-01

    Flow and water-quality data for surface water in the north Georgia coal region is presented in this report. The data were collected by TVA and the USGS; the TVA data were collected in July 1981 and the USGS data were collected primarily from 1979 through 1981, with some dating back to 1976. An analysis of the potential for surface-water quantity and quality problems due to future surface mining of coal is also presented. Several areas exhibiting this potential are listed, with the potential for erosion being the most widespread and the potential for acid drainage being localized but more difficult to prevent. 43 references, 6 figures, 14 tables.

  4. Circumnutation on the water surface: female flowers of Vallisneria

    PubMed Central

    Kosuge, Keiko; Iida, Satoko; Katou, Kiyoshi; Mimura, Tetsuro

    2013-01-01

    Circumnutation, the helical movement of growing organ tips, is ubiquitous in land plants. The mechanisms underlying circumnutation have been debated since Darwin's time. Experiments in space and mutant analyses have revealed that internal oscillatory (tropism-independent) movement and gravitropic response are involved in circumnutation. Female flower buds of tape grass (Vallisneria asiatica var. biwaensis) circumnutate on the water surface. Our observations and experiments with an artificial model indicated that gravitropism is barely involved in circumnutation. Instead, we show that helical intercalary growth at the base of peduncle plays the primary role in all movements in Vallisneria. This growth pattern produces torsional bud rotation, and gravity and buoyancy forces have a physical effect on the direction of peduncle elongation, resulting in bud circumnutation on the water surface. In contrast to other water-pollinated hydrophilous plants, circumnutation in Vallisneria enables female flowers to actively collect male flowers from a larger surface area of water. PMID:23355948

  5. Index of surface-water stations in Texas, January 1989

    USGS Publications Warehouse

    Rawson, Jack; Carrillo, E.R.; Buckner, H.D.

    1989-01-01

    As of January 1, 1989, the surface-water data-collection network in Texas included 373 continuous-streamflow, 75 continuous or daily reservoir-content, 37 gage-height, 15 crest-stage partial-record, 200 data collection platform, 7 periodic discharge through range, 27 flood-hydrograph partial-record, 27 low-flow partial-record, 43 daily chemical-quality, 17 continuous-recording water quality, 87 periodic biological, 11 lake survey, 159 period organic and (or) nutrient, 2 periodic insecticide, 28 periodic pesticide, 19 automatic sampler, 137 periodic minor element, 126 periodic chemical-quality, 75 periodic physical organic, 17 continuous-recording temperature, and 29 national stream-gaging accounting network stations. Plate 1 shows the location of surface-water streamflow or reservoir-content and chemical-quality or sediment stations in Texas. Plate 2 shows the location of partial-record surface-water stations. (USGS)

  6. Thermal surface signatures of ship propeller wakes in stratified waters

    NASA Astrophysics Data System (ADS)

    Voropayev, S. I.; Nath, C.; Fernando, H. J. S.

    2012-11-01

    When a ship moves in temperature stratified water, e.g., in the ocean diurnal thermocline, the propeller(s) as well as the turbulent boundary layer of the hull mix the surface water with underlying colder fluid. As a result, when observed from above, a temperature "wake signature" of ˜1-2 °C may be detected at the water surface. To quantify this phenomenon, theoretical modeling and physical experiments were conducted. The dominant processes responsible for thermal wake generation were identified and parameterized. Most important similarity parameters were derived and estimates for wake signature contrast were made. To verify model predictions, scaled experiments were conducted, with the water surface temperature measured using a sensitive infrared camera. Comparison of laboratory measurements with model estimates has shown satisfactory agreement, both qualitative and quantitatively. Estimates for ocean ship-wake scenarios are also given, which are supported by available field observations.

  7. Chemical contamination and the ecological quality of surface water.

    PubMed

    Baas, Jan; Kooijman, Bas

    2010-05-01

    In the assessment of the quality of surface waters, the typical procedure is that the concentration of contaminants in the surface water is monitored and subsequently compared with their respective Maximum Permissible Concentrations (MPCs). If the MPCs are not exceeded the water quality is considered to be safe. But can we be certain that this is true? We compared MPCs to observed and calculated effects of measured contaminants in Dutch surface waters and showed that effects of mixtures can cause a daphnid population to go extinct within 30h of exposure even when MPCs are not exceeded. We conclude that there are shortcomings underlying the concepts of the MPCs. And that the MPCs aim to protect 95% of all species is not met. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. Experimental water droplet impingement data on modern aircraft surfaces

    NASA Technical Reports Server (NTRS)

    Papadakis, Michael; Breer, Marlin D.; Craig, Neil C.; Bidwell, Colin S.

    1991-01-01

    An experimental method has been developed to determine the water droplet impingement characteristics on two- and three-dimensional aircraft surfaces. The experimental water droplet impingement data are used to validate particle trajectory analysis codes that are used in aircraft icing analyses and engine inlet particle separator analyses. The aircraft surface is covered with thin strips of blotter paper in areas of interest. The surface is then exposed to an airstream that contains a dyed-water spray cloud. The water droplet impingement data are extracted from the dyed blotter paper strips by measuring the optical reflectance of each strip with an automated reflectometer. Preliminary experimental and analytical impingement efficiency data are presented for a NLF(1)-0414F airfoil, s swept MS(1)-0317 airfoil, a swept NACA 0012 wingtip and for a Boeing 737-300 engine inlet model.

  9. Experimental water droplet impingement data on modern aircraft surfaces

    NASA Technical Reports Server (NTRS)

    Papadakis, Michael; Breer, Marlin D.; Craig, Neil C.; Bidwell, Colin S.

    1991-01-01

    An experimental method has been developed to determine the water droplet impingement characteristics on two- and three-dimensional aircraft surfaces. The experimental water droplet impingement data are used to validate particle trajectory analysis codes that are used in aircraft icing analyses and engine inlet particle separator analyses. The aircraft surface is covered with thin strips of blotter paper in areas of interest. The surface is then exposed to an airstream that contains a dyed-water spray cloud. The water droplet impingement data are extracted from the dyed blotter paper strips by measuring the optical reflectance of each strip with an automated reflectometer. Preliminary experimental and analytical impingement efficiency data are presented for a NLF(1)-0414F airfoil, s swept MS(1)-0317 airfoil, a swept NACA 0012 wingtip and for a Boeing 737-300 engine inlet model.

  10. The Proposed Surface Water and Ocean Topography (SWOT) Mission

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry

    2012-01-01

    A new space mission concept called Surface Water and Ocean Topography (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.

  11. The Proposed Surface Water and Ocean Topography (SWOT) Mission

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng; Alsdorf, Douglas; Rodriguez, Ernesto; Morrow, Rosemary; Mognard, Nelly; Vaze, Parag; Lafon, Thierry

    2012-01-01

    A new space mission concept called Surface Water and Ocean Topography (SWOT) is being developed jointly by a collaborative effort of the international oceanographic and hydrological communities for making high-resolution measurement of the water elevation of both the ocean and land surface water to answer the questions about the oceanic submesoscale processes and the storage and discharge of land surface water. The key instrument payload would be a Ka-band radar interferometer capable of making high-resolution wide-swath altimetry measurement. This paper describes the proposed science objectives and requirements as well as the measurement approach of SWOT, which is baselined to be launched in 2019. SWOT would demonstrate this new approach to advancing both oceanography and land hydrology and set a standard for future altimetry missions.

  12. On chlorine salts: Their detection, stability and implications for water on Mars and Europa

    NASA Astrophysics Data System (ADS)

    Hanley, Jennifer

    Chlorine salts (e.g. chlorides, chlorates and perchlorates) are an important factor in the stability of water on the surfaces of planetary bodies. Here we have shown that perchlorate and chlorate salts will lower the freezing point of water, allowing it to be liquid down to ~204 K. These salts will also slow down the evaporation rate, extending the lifetime of the liquid water solution. Chlorine salts have been detected on Mars, which has significant implications for the stability of water and hence its habitability. To study their effects on the stability of water on planetary surfaces, we need to first locate where these chlorine salts exist; this is typically done by remote sensing. To date, only anhydrous chlorides have been remotely detected, mostly due to the lack of hydrated chlorine salts in the spectral libraries used to identify features. To address this deficit, we measured reflectance spectra for numerous chlorine salts. Hydration bands were most common in near-infrared spectra, with band depth and width increasing with increasing hydration state. In the mid-infrared, oxychlorine salts exhibit spectral features due to Cl-O vibrations. We also investigated the spectral features of these salts at low temperature (80 K) to compare with remote sensing data of the outer satellites, specifically Europa. At low temperature, water bands become narrower and shallower than their room temperature counterparts. We show that chlorine salts do possess distinct spectral features that should allow for their detection by remote sensing, though care must be taken to acquire laboratory spectra of all hydrated phases at the relevant conditions (e.g. temperature, pressure) for the planetary body being studied.

  13. On Chlorine Salts: Their Detection, Stability and implications for Water on Mars and Europa

    NASA Astrophysics Data System (ADS)

    Hanley, Jennifer

    2013-10-01

    Chlorine salts (e.g. chlorides, chlorates and perchlorates) are an important factor in the stability of water on the surfaces of planetary bodies. Here we have shown that perchlorate and chlorate salts will lower the freezing point of water, allowing it to be liquid down to ~204 K. These salts will also slow down the evaporation rate, extending the lifetime of the liquid water solution. Chlorine salts have been detected on Mars, which has significant implications for the stability of water and hence its habitability. To study their effects on the stability of water on planetary surfaces, we need to first locate where these chlorine salts exist; this is typically done by remote sensing. To date, only anhydrous chlorides have been remotely detected, mostly due to the lack of hydrated chlorine salts in the spectral libraries used to identify features. To address this deficit, we measured reflectance spectra for numerous chlorine salts. Hydration bands were most common in near-infrared spectra, with band depth and width increasing with increasing hydration state. In the mid-infrared, oxychlorine salts exhibit spectral features due to Cl-O vibrations. We also investigated the spectral features of these salts at low temperature (80 K) to compare with remote sensing data of the outer satellites, specifically Europa. At low temperature, water bands become narrower and shallower than their room temperature counterparts. We show that chlorine salts do possess distinct spectral features that should allow for their detection by remote sensing, though care must be taken to acquire laboratory spectra of all hydrated phases at the relevant conditions (e.g. temperature, pressure) for the planetary body being studied.

  14. Hydrodynamic interaction between rigid surfaces planing on water

    NASA Astrophysics Data System (ADS)

    Bari, Ghazi; Matveev, Konstantin

    2016-11-01

    This study addresses hydrodynamic interaction of multi-surface planing hulls in the linearized, inviscid, steady flow approximation. A potential-flow-based hydrodynamic sources are distributed on the water surface to model water flow around three-dimensional hulls at finite Froude numbers. The pressure distribution on the hull surfaces are calculated as a part of the solution, and then the lift force and center of pressure are determined. For validation, numerical results are compared with an available analytical solution, experimental results, and empirical correlation equations. Parametric calculations are carried out for different hull designs in variable speed regimes, hull aspect ratios, deadrise angles and hull spacings. Results are presented for the lift coefficient, drag components, lift-drag ratio, center of pressure, and some illustrations are given for the water surface elevations. Obtained results can assist naval architects in improving design of high speed marine vehicles.

  15. Thin water film formation on metal oxide crystal surfaces.

    PubMed

    Gilbert, Benjamin; Katz, Jordan E; Rude, Bruce; Glover, T E; Hertlein, Marcus P; Kurz, Charles; Zhang, Xiaoyi

    2012-10-09

    Reactions taking place at hydrated metal oxide surfaces are of considerable environmental and technological importance. Surface-sensitive X-ray methods can provide structural and chemical information on stable interfacial species, but it is challenging to perform in situ studies of reaction kinetics in the presence of water. We have implemented a new approach to creating a micrometer-scale water film on a metal oxide surface by combining liquid and gas jets on a spinning crystal. The water films are stable indefinitely and sufficiently thin to allow grazing incidence X-ray reflectivity and spectroscopy measurements. The approach will enable studies of a wide range of surface reactions and is compatible with interfacial optical-pump/X-ray-probe studies.

  16. Organic and Inorganic Species in CBM Produced Water: Implications for Water Management Strategies

    NASA Astrophysics Data System (ADS)

    Kharaka, Y. K.; Rice, C. A.

    2003-12-01

    Coal-bed methane (CBM) wells currently produce close to one billion bbl of water annually and deliver about 8% of total natural gas in the USA. The salinity of this produced water generally is lower than that of water from conventional petroleum wells; salinity commonly is 1,000-20,000 mg/L, but ranges from 200 to 150,000 mg/L TDS. Most CBM wells produce Na-HCO3-Cl type water that is low in trace metals and has no reported NORMs. This water generally has no oil and grease and has relatively low (2-10 mg/L) dissolved organic carbon (DOC), but its organic composition has not been characterized in detail. The water is disposed of by injection into saline aquifers, through evaporation and/or percolation in disposal pits, road spreading, and surface discharge. Water that has low (<1,000 mg/L TDS) salinity and sodium adsorption ratio (SAR) is considered acceptable for irrigation, surface discharge and for injection into freshwater aquifers. Because groundwater associated with coal, especially with lignite and subbituminous coal, is known to contain a variety of toxic or potentially toxic organics, including hydroxyphenols and PAHs, the organic and inorganic compositions of CBM waters should be systematically characterized and their potential for harm to human health, crops and the environment carefully evaluated prior to its addition to existing water supplies. As an alternative to costly disposal, lower salinity produced water from high-yield CBM wells is being considered for reclamation. The treated water would be a valuable new water resource, especially in the arid western USA. The feasibility and cost of reclaiming produced water to meet irrigation, industrial and drinking water standards was evaluated in a 10 gpm pilot field study. The estimated treatment cost was high at about 0.39/bbl (3,000/acre-ft) for potable water, but would be substantially lower and competitive for irrigation and industrial uses in some arid regions of the USA.

  17. The influence of lithology on surface water sources | Science ...

    EPA Pesticide Factsheets

    Understanding the temporal and spatial variability of surface water sources within a basin is vital to our ability to manage the impacts of climate variability and land cover change. Water stable isotopes can be used as a tool to determine geographic and seasonal sources of water at the basin scale. Previous studies in the Coastal Range of Oregon reported that the variation in the isotopic signatures of surface water does not conform to the commonly observed “rainout effect”, which exhibits a trend of increasing isotopic depletion with rising elevation. The primary purpose of this research is to investigate the mechanisms governing seasonal and spatial variations in the isotopic signature of surface waters within the Marys River Basin, located in the leeward side of the Oregon Coastal Range. Surface water and precipitation samples were collected every 2-3 weeks for isotopic analysis of δ18O and δ2H for one year. Results indicate a significant difference in isotopic signature between watersheds underlain by basalt and sandstone. The degree of separation was the most distinct during the summer when low flows reflect deeper groundwater sources, whereas isotopic signatures during the rainy season (fall and winter) showed a greater degree of similarity between the two lithologies. This indicates that baseflow within streams drained by sandstone versus basalt is being supplied from two distinctly separate water sources. In addition, Marys River flow at the outle

  18. High Conductivity Water Treatment Using Water Surface Discharge with Nonmetallic Electrodes

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Zhang, Xingwang; Lei, Lecheng

    2013-06-01

    Although electrohydraulic discharge is effective for wastewater treatment, its application is restricted by water conductivity and limited to the treatment of low conductivity water. For high conductivity water treatment, water-surface discharge is the preferred choice. However, the metallic electrodes are easily corroded because of the high temperature and strong oxidative environment caused by gas phase discharge and the electrochemical reaction in water. As a result, the efficiency of the water treatment might be affected and the service life of the reactor might be shortened. In order to avoid the corrosion problem, nonmetallic electrode water-surface discharge is introduced into high conductivity water treatment in the present study. Carbon-felt and water were used as the high voltage electrode and ground electrode, respectively. A comparison of the electrical and chemical characteristics showed that nonmetallic electrode discharge maintained the discharge characteristics and enhanced the energy efficiency, and furthermore, the corrosion of metal electrodes was avoided.

  19. Graphene drape minimizes the pinning and hysteresis of water drops on nanotextured rough surfaces.

    PubMed

    Singh, Eklavya; Thomas, Abhay V; Mukherjee, Rahul; Mi, Xi; Houshmand, Farzad; Peles, Yoav; Shi, Yunfeng; Koratkar, Nikhil

    2013-04-23

    Previous studies of the interaction of water with graphene-coated surfaces have been limited to flat (smooth) surfaces. Here we created a rough surface by nanopatterning and then draped the surface with a single-layer graphene sheet. We found that the ultrasheer graphene drape prevents the penetration of water into the textured surface thereby drastically reducing the contact angle hysteresis (which is a measure of frictional energy dissipation) and preventing the liquid contact line from getting pinned to the substrate. This has important technological implications since the main obstacle to the motion of liquid drops on rough surfaces is contact angle hysteresis and contact line pinning. Graphene drapes could therefore enable enhanced droplet mobility which is required in a wide range of applications in micro and nanofluidics. Compared to polymer coatings that could fill the cavities between the nano/micropores or significantly alter the roughness profile of the substrate, graphene provides the thinnest (i.e., most sheer) and most conformal drape that is imaginable. Despite its extreme thinness, the graphene drape is mechanically robust, chemically stable, and offers high flexibility and resilience which can enable it to reliably drape arbitrarily complex surface topologies. Graphene drapes may therefore provide a hitherto unavailable ability to tailor the dynamic wettability of surfaces for a variety of applications.

  20. Water in the lunar interior: Implications for early evolution of the moon.

    NASA Astrophysics Data System (ADS)

    Goswami, Jitendranath

    2016-07-01

    Water in the lunar interior: Implications for early evolution of the moon. J. N. Goswami*, A. Basu Sarbadhikari and K. K. Marhas Physical Research Laboratory, Ahmedabad-38009 Water and other volatiles present in lunar interior can significantly affect the early evolution of the moon. Lunar volcanic glasses and in olivine hosted melt inclusions, suggest water content ranging from ~700 to 1400 ppm in the deep lunar interior (≥500 km). Apatite in lunar basalts, that sampled magma at a shallower depth (<200 km) show significant volatile zoning making it difficult to retrieve their source volatile content. We have identified and analysed apatite in Apollo 15 sample that formed at 150-200 km below the lunar surface, in a closed system and devoid of volatile zoning. The analyses of volatiles were done using a Nano-SIMs in the imaging mode and terrestrial apatite was used as standard. Water content in two apatite grains are in the range of 2200-2850 and 3400-3750 ppm, respectively; F and Cl also show nearly uniform distribution. Considering reasonable partition coefficient of water between apatite and basaltic melt, we infer values of ~ 100-160 ppm (water), 80-90 ppm (F) and 10-20 ppm (Cl) in the parent magma of 15555 that sampled a lunar depth of 150-200 km. These values are much lower than those for lunar volcanic glasses and melt inclusions trapped in them and strongly suggest a non-uniform distribution of water and other volatiles in the lunar interior. Presence of water in lunar mantle could have significantly affected the early evolution of Moon and, in particular helped in sustaining a lunar core dynamo for an extended duration and can also influence thermo-chemical processes, e.g. differential degree of melting, in different mantle source regions during the early evolutionary stages of the Moon.

  1. Curvature-dependent surface energy and implications for nanostructures

    NASA Astrophysics Data System (ADS)

    Chhapadia, P.; Mohammadi, P.; Sharma, P.

    2011-10-01

    At small length scales, several size-effects in both physical phenomena and properties can be rationalized by invoking the concept of surface energy. Conventional theoretical frameworks of surface energy, in both the mechanics and physics communities, assume curvature independence. In this work we adopt a simplified and linearized version of a theory proposed by Steigmann-Ogden to capture curvature-dependence of surface energy. Connecting the theory to atomistic calculations and the solution to an illustrative paradigmatical problem of a bent cantilever beam, we catalog the influence of curvature-dependence of surface energy on the effective elastic modulus of nanostructures. The observation in atomistic calculations that the elastic modulus of bent nanostructures is dramatically different than under tension - sometimes softer, sometimes stiffer - has been a source of puzzlement to the scientific community. We show that the corrected surface mechanics framework provides a resolution to this issue. Finally, we propose an unambiguous definition of the thickness of a crystalline surface.

  2. Surface tension isotherms of the dioxane-acetone-water and glycerol-ethanol-water ternary systems

    NASA Astrophysics Data System (ADS)

    Dzhambulatov, R. S.; Dadashev, R. Kh.; Elimkhanov, D. Z.; Dadashev, I. N.

    2016-10-01

    The results of the experimental and theoretical studies of the concentration dependence of surface tension of aqueous solutions of the 1,4-dioxane-acetone-water and glycerol-ethanol-water ternary systems were given. The studies were performed by the hanging-drop method on a DSA100 tensiometer. The maximum error of surface tension was 1%. The theoretical models for calculating the surface tension of the ternary systems of organic solutions were analyzed.

  3. Hybrid Analysis of Blue Water Consumption and Water Scarcity Implications at the Global, National, and Basin Levels in an Increasingly Globalized World.

    PubMed

    Wang, Ranran; Zimmerman, Julie

    2016-05-17

    As the fifth global water footprint assessment, this study enhanced previous estimates of national blue water consumption (including fresh surface and groundwater) and main economic activities with (1) improved spatial and sectoral resolution and (2) quantified the impacts of virtual water trade on water use and water stress at both the national and basin level. In 2007, 1194 Gm(3) of blue water was consumed globally for human purposes. The consuming (producing) of primary and manufactured goods and services from the sectors of "Primary Crops and Livestock", "Primary Energy and Minerals", "Processed Food and Beverages", "Non-food Manufactured Products", "Electricity", "Commercial and Public Services", and "Households" accounted for 33% (91%), ∼ 0% (1%), 37% (<1%), 13% (1%), 1% (2%), 15% (3%), and 2% (2%) of the world's total blue water consumption, respectively. The considerable differences in sectoral water consumption accounted for by the two perspectives (consumption- vs production-based) highlight the significance of the water consumed indirectly, upstream in the supply chain (i.e., > 70% of total blue water consumption) while offering additional insights into the water implications of critical interconnected economic activities, such as the water-energy nexus. With 145 Gm(3) (12%) of the blue water consumption embedded in the goods and services traded internationally, 89 countries analyzed were net blue water importers at the national level. On the basin level, the impacts of virtual water trade on water stress were statistically significant for basins across the world and within 104 countries; virtual water trade mitigated water stress for the basins within 85 of the 104 countries, including all of those where there are moderate and greater water stress countrywide (except Italy).

  4. DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT

    EPA Science Inventory

    A ground-water/surface-water interface (GSI) was documented at the Thermo Chem CERCLA Site in Muskegon, MI via direct-push (DP) sampling. At that time, contaminated ground water flowed from the upland area of the site into the Black Creek floodplain. DP rods equipped with a 1.5...

  5. ARSENIC SORUCE IDENTIFICATION AT THE GROUND WATER-SURFACE WATER INTERACTION ZONE AT A CONTAMINATED SITE

    EPA Science Inventory

    One of the challenges in assessing the current impact of the discharge of arsenic contaminated ground water into a surface water body is differentiating the arsenic ground-water flux versus dissolution of in-place contaminated sediments. A field investigation has been carried ou...

  6. 77 FR 12227 - Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ... AGENCY 40 CFR Parts 141 and 142 Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public Meeting AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of public..., concerning information that may inform the regulatory review of the uncovered finished water reservoir...

  7. ARSENIC SORUCE IDENTIFICATION AT THE GROUND WATER-SURFACE WATER INTERACTION ZONE AT A CONTAMINATED SITE

    EPA Science Inventory

    One of the challenges in assessing the current impact of the discharge of arsenic contaminated ground water into a surface water body is differentiating the arsenic ground-water flux versus dissolution of in-place contaminated sediments. A field investigation has been carried ou...

  8. Supplementary report on surface-water and ground-water surveys, Nueces River Basin, Texas

    USGS Publications Warehouse

    Broadhurst, W.L.; Ellsworth, C.E.

    1950-01-01

    A report on the ground-water and surface-water surveys of the Nueces River Basin was included in a report by the Bureau of Reclamation, entitled "Comprehensive plan for water-resources development of the Nueces River Basin project planning report number 5-14.04-3, February 1946".

  9. DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT

    EPA Science Inventory

    A ground-water/surface-water interface (GSI) was documented at the Thermo Chem CERCLA Site in Muskegon, MI via direct-push (DP) sampling. At that time, contaminated ground water flowed from the upland area of the site into the Black Creek floodplain. DP rods equipped with a 1.5...

  10. Hydrochemical characteristics and water quality assessment of surface water and groundwater in Songnen plain, Northeast China.

    PubMed

    Zhang, Bing; Song, Xianfang; Zhang, Yinghua; Han, Dongmei; Tang, Changyuan; Yu, Yilei; Ma, Ying

    2012-05-15

    Water quality is the critical factor that influence on human health and quantity and quality of grain production in semi-humid and semi-arid area. Songnen plain is one of the grain bases in China, as well as one of the three major distribution regions of soda saline-alkali soil in the world. To assess the water quality, surface water and groundwater were sampled and analyzed by fuzzy membership analysis and multivariate statistics. The surface water were gather into class I, IV and V, while groundwater were grouped as class I, II, III and V by fuzzy membership analysis. The water samples were grouped into four categories according to irrigation water quality assessment diagrams of USDA. Most water samples distributed in category C1-S1, C2-S2 and C3-S3. Three groups were generated from hierarchical cluster analysis. Four principal components were extracted from principal component analysis. The indicators to water quality assessment were Na, HCO(3), NO(3), Fe, Mn and EC from principal component analysis. We conclude that surface water and shallow groundwater are suitable for irrigation, the reservoir and deep groundwater in upstream are the resources for drinking. The water for drinking should remove of the naturally occurring ions of Fe and Mn. The control of sodium and salinity hazard is required for irrigation. The integrated management of surface water and groundwater for drinking and irrigation is to solve the water issues.

  11. Structural and dynamical properties of water on chemically modified surfaces: The role of the instantaneous surface

    NASA Astrophysics Data System (ADS)

    Bekele, Selemon; Tsige, Mesfin

    Surfaces of polymers such as atactic polystyrene (aPS) represent very good model systems for amorphous material surfaces. Such polymer surfaces are usually modified either chemically or physically for a wide range of applications that include friction, lubrication and adhesion. It is thus quite important to understand the structural and dynamical properties of liquids that come in contact with them to achieve the desired functional properties. Using molecular dynamics (MD) simulations, we investigate the structural and dynamical properties of water molecules in a slab of water in contact with atactic polystyrene surfaces of varying polarity. We find that the density of water molecules and the number distribution of hydrogen bonds as a function of distance relative to an instantaneous surface exhibit a structure indicative of a layering of water molecules near the water/PS interface. For the dynamics, we use time correlation functions of hydrogen bonds and the incoherent structure function for the water molecules. Our results indicate that the polarity of the surface dramatically affects the dynamics of the interfacial water molecules with the dynamics slowing down with increasing polarity. This work was supported by NSF Grant DMR1410290.

  12. Surface melting of clusters and implications for bulk matter

    NASA Astrophysics Data System (ADS)

    Cheng, Hai-Ping; Berry, R. Stephen

    1992-06-01

    Surface melting on clusters is investigated by a combination of analytic modeling and computer simulation. Homogeneous argonlike clusters bound by Lennard-Jones forces and Cu-like clusters bound by ``embedded-atom'' potentials are the systems considered. Molecular-dynamics calculations have been carried out for clusters with 40-147 atoms. Well below the bulk melting temperature, the surfaces become very soft, exhibiting well-defined diffusion constants even while the cores remain nearly rigid and solidlike. The simulations, particularly animations, of atomic motion reveal that the surface melting is associated not with amorphous, random surface structures in constant, irregular motion, but rather with large-amplitude, organized, collective motion of most of the surface atoms accompanied by a few detached atoms (``floaters'') and holes. At any time, a few of the surface atoms are out of the surface layer, leaving vacancies; these promoted particles wander diffusively, the holes also but less so; the floaters occasionally exchange with atoms in the surface layer. This result is the basis for an analytic, statistical model. The caloric curves, particularly the latent heats, together with the results from an analytical model, show that surface melting of clusters is a ``phase change'' different from the homogeneous melting of clusters.

  13. Multi-Decadal Surface Water Dynamics in North American Tundra

    NASA Technical Reports Server (NTRS)

    Carroll, Mark L.; Loboda, Tatiana V.

    2017-01-01

    Over the last several decades, warming in the Arctic has outpaced the already impressive increases in global mean temperatures. The impact of these increases in temperature has been observed in a multitude of ecological changes in North American tundra including changes in vegetative cover, depth of active layer, and surface water extent. The low topographic relief and continuous permafrost create an ideal environment for the formation of small water bodies - a definitive feature of tundra surface. In this study, water bodies in Nunavut territory in northern Canada were mapped using a long-term record of remotely sensed observations at 30 meters spatial resolution from the Landsat suite of instruments. The temporal trajectories of water extent between 1985 and 2015 were assessed. Over 675,000 water bodies have been identified over the 31-year study period with over 168,000 showing a significant (probability is less than 0.05) trend in surface area. Approximately 55 percent of water bodies with a significant trend were increasing in size while the remaining 45 percent were decreasing in size. The overall net trend for water bodies with a significant trend is 0.009 hectares per year per water body.

  14. Evaluation of automated urban surface water extraction from Sentinel-2A imagery using different water indices

    NASA Astrophysics Data System (ADS)

    Yang, Xiucheng; Chen, Li

    2017-04-01

    Urban surface water is characterized by complex surface continents and small size of water bodies, and the mapping of urban surface water is currently a challenging task. The moderate-resolution remote sensing satellites provide effective ways of monitoring surface water. This study conducts an exploratory evaluation on the performance of the newly available Sentinel-2A multispectral instrument (MSI) imagery for detecting urban surface water. An automatic framework that integrates pixel-level threshold adjustment and object-oriented segmentation is proposed. Based on the automated workflow, different combinations of visible, near infrared, and short-wave infrared bands in Sentinel-2 image via different water indices are first compared. Results show that object-level modified normalized difference water index (MNDWI with band 11) and automated water extraction index are feasible in urban surface water mapping for Sentinel-2 MSI imagery. Moreover, comparative results are obtained utilizing optimal MNDWI from Sentinel-2 and Landsat 8 images, respectively. Consequently, Sentinel-2 MSI achieves the kappa coefficient of 0.92, compared with that of 0.83 from Landsat 8 operational land imager.

  15. Experimental Values of the Surface Tension of Supercooled Water

    NASA Technical Reports Server (NTRS)

    Hacker, P. T.

    1951-01-01

    The results of surface-tension measurements for supercooled water are presented. A total of 702 individual measurements of surface tension of triple-distilled water were made in the temperature range, 27 to -22.2 C, with 404 of these measurements at temperatures below 0 C. The increase in magnitude of surface tension with decreasing temperature, as indicated by measurements above 0 C, continues to -22.2 C. The inflection point in the surface-tension - temperature relation in the vicinity of 0 C, as indicated by the International Critical Table values for temperatures down to -8 C, is substantiated by the measurements in the temperature range, 0 to -22.2 C. The surface tension increases at approximately a linear rate from a value of 76.96+/-0.06 dynes per centimeter at -8 C to 79.67+/-0.06 dynes per centimeter at -22.2 C.

  16. Influence of surface structure and chemistry on water droplet splashing.

    PubMed

    Koch, Kerstin; Grichnik, Roland

    2016-08-06

    Water droplet splashing and aerosolization play a role in human hygiene and health systems as well as in crop culturing. Prevention or reduction of splashing can prevent transmission of diseases between animals and plants and keep technical systems such as pipe or bottling systems free of contamination. This study demonstrates to what extent the surface chemistry and structures influence the water droplet splashing behaviour. Smooth surfaces and structured replicas of Calathea zebrina (Sims) Lindl. leaves were produced. Modification of their wettability was done by coating with hydrophobizing and hydrophilizing agents. Their wetting was characterized by contact angle measurement and splashing behaviour was observed with a high-speed video camera. Hydrophobic and superhydrophilic surfaces generally showed fewer tendencies to splash than hydrophobic ones. Structuring amplified the underlying behaviour of the surface chemistries, increasing hydrophobic surfaces' tendency to splash and decreasing splash on hydrophilic surfaces by quickly transporting water off the impact point by capillary forces. The non-porous surface structures found in C. zebrina could easily be applied to technical products such as plastic foils or mats and coated with hydrophilizing agents to suppress splash in areas of increased hygiene requirements or wherever pooling of liquids is not desirable.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'.

  17. Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

    PubMed Central

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  18. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water.

  19. Origin of subdiffusion of water molecules on cell membrane surfaces

    PubMed Central

    Yamamoto, Eiji; Akimoto, Takuma; Yasui, Masato; Yasuoka, Kenji

    2014-01-01

    Water molecules play an important role in providing unique environments for biological reactions on cell membranes. It is widely believed that water molecules form bridges that connect lipid molecules and stabilize cell membranes. Using all-atom molecular dynamics simulations, we show that translational and rotational diffusion of water molecules on lipid membrane surfaces exhibit subdiffusion and aging. Moreover, we provide evidence that both divergent mean trapping time (continuous-time random walk) and long-correlated noise (fractional Brownian motion) contribute to this subdiffusion. These results suggest that subdiffusion on cell membranes causes the water retardation, an enhancement of cell membrane stability, and a higher reaction efficiency. PMID:24739933

  20. Solitary Water Waves of Large Amplitude Generated by Surface Pressure

    NASA Astrophysics Data System (ADS)

    Wheeler, Miles H.

    2015-11-01

    We consider exact nonlinear solitary water waves on a shear flow with an arbitrary distribution of vorticity. Ignoring surface tension, we impose a non-constant pressure on the free surface. Starting from a uniform shear flow with a flat free surface and a supercritical wave speed, we vary the surface pressure and use a continuation argument to construct a global connected set of symmetric solitary waves. This set includes waves of depression whose profiles increase monotonically from a central trough where the surface pressure is at its lowest, as well as waves of elevation whose profiles decrease monotonically from a central crest where the surface pressure is at its highest. There may also be two waves in this connected set with identical surface pressure, only one of which is a wave of depression.

  1. Water resources in the twenty-first century; a study of the implications of climate uncertainty

    USGS Publications Warehouse

    Moss, Marshall E.; Lins, Harry F.

    1989-01-01

    The interactions of the water resources on and within the surface of the Earth with the atmosphere that surrounds it are exceedingly complex. Increased uncertainty can be attached to the availability of water of usable quality in the 21st century, therefore, because of potential anthropogenic changes in the global climate system. For the U.S. Geological Survey to continue to fulfill its mission with respect to assessing the Nation's water resources, an expanded program to study the hydrologic implications of climate uncertainty will be required. The goal for this program is to develop knowledge and information concerning the potential water-resources implications for the United States of uncertainties in climate that may result from both anthropogenic and natural changes of the Earth's atmosphere. Like most past and current water-resources programs of the Geological Survey, the climate-uncertainty program should be composed of three elements: (1) research, (2) data collection, and (3) interpretive studies. However, unlike most other programs, the climate-uncertainty program necessarily will be dominated by its research component during its early years. Critical new concerns to be addressed by the research component are (1) areal estimates of evapotranspiration, (2) hydrologic resolution within atmospheric (climatic) models at the global scale and at mesoscales, (3) linkages between hydrology and climatology, and (4) methodology for the design of data networks that will help to track the impacts of climate change on water resources. Other ongoing activities in U.S. Geological Survey research programs will be enhanced to make them more compatible with climate-uncertainty research needs. The existing hydrologic data base of the Geological Survey serves as a key element in assessing hydrologic and climatologic change. However, this data base has evolved in response to other needs for hydrologic information and probably is not as sensitive to climate change as is

  2. [Distribution of arsenic in surface water in Tibet].

    PubMed

    Wang, Ming-Guo; Li, She-Hong; Wang, Hui; Xiao, Tang-Fu; Zheng, Bao-Shan

    2012-10-01

    This research was aimed on studying the arsenic distribution of water in Yarlung Zangbo and Singe Zangbo basins in Tibet. Results showed that arsenic concentrations were different in different types of the water. The sequence of arsenic concentration from high to low was hot spring water (4920 microg x L(-1) +/- 1520 microg x L(-1), n =2), salt lake water (2180 microg x L(-1) +/- 3840 microg x L(-1), n =7), well water (194 microg x L(-1), n = 1), freshwater lake water (163 microg x L(-1) +/- 202 microg x L(-1), n =2) and stream water (35.5 microg x L(-1) +/- 57.0 microg x L(-1), n=74). The high arsenic concentration in surface water in Singe Zangbo and the upstream of Yarlung Zangbo were found. The average concentration of arsenic in water from Singe Zangbo (58.4 microg x L(-1) +/- 69.9 microg x L(-1), n = 39) was significantly higher than that from Yarlung Zangbo (10.8 microg x L(-1) +/- 16.9 microg x L(-1), n = 30). Arsenic concentration in 43.2% of stream water samples and all of the hot springs, saline lakes and well water were higher than 10 microg x L(-1). Yarlung Zangbo and Singe Zangbo are important sources of drinking water for the local people. There is a high risk for the local people who may suffer from chronic arsenic poisoning.

  3. A Mechanism for Near-Surface Water Ice on Mars

    NASA Astrophysics Data System (ADS)

    Travis, B. J.; Feldman, W. C.; Maurice, S.

    2009-12-01

    Recent findings (e.g., Byrne et al, 2009) indicate that water ice lies very close to the surface at mid-latitudes on Mars. Re-interpretation of neutron and gamma-ray data is consistent with water ice buried less than a meter or two below the surface. Hydrothermal convection of brines provides a mechanism for delivering water to the near-surface. Previous numerical and experimental studies with pure water have indicated that hydrothermal circulation of pore water should be possible, given reasonable estimates of geothermal heat flux and regolith permeability. For pure water convection, the upper limit of the liquid zone would lie at some depth, but in the case of salt solutions, the boundary between liquid and frozen pore water could reach virtually to the surface. The principal drivers for hydrothermal circulation are regolith permeability, geothermal heat flux, surface temperature and salt composition. Both the Clifford and the Hanna-Phillips models of Martian regolith permeability predict sufficiently high permeabilities to sustain hydrothermal convection. Salts in solution will concentrate in upwelling plumes as the cold surface is approached. As water ice is excluded upon freezing, the remaining solution becomes a more concentrated brine, reaching its eutectic concentration before freezing. Numerical simulations considering several salts (NaCl, CaCl2, MgSO4), and a range of heat fluxes (20 - 100 mW/m2) covering the range of estimated present day heat flux (20 to 40 mW/m2) to moderately elevated conditions (60 to 100 mW/m2) such as might exist in the vicinity of volcanoes and craters, all indicate the same qualitative behavior. A completely liquid, convective regime occurs at depth, overlain by a partially frozen "mushy" layer (but still convecting despite the increased viscosity), overlain by a thin frozen layer at the surface. The thicknesses of these layers depend on the heat flux, surface temperature and the salt. As heat flux increases, the mushy region

  4. Scratching the surface of the water dication

    NASA Astrophysics Data System (ADS)

    Van Huis, Timothy J.; Wesolowski, Steven S.; Yamaguchi, Yukio; Schaefer, Henry F.

    1999-06-01

    The X˜ 3Σg-, ã 1Δg, and b˜ 1Σg+ states of the water dication, H2O2+, have been investigated using several high-level ab initio methods and a range of basis sets. With Dunning's augmented correlation consistent polarized valence quadruple-ζ (aug-cc-pVQZ) basis set at the complete active space self-consistent field second-order configuration interaction (CAS-SOCI) level, it is confirmed that the ground and first two excited states of H2O2+ are all of D∞h symmetry, in violation of Walsh's rules for 6 valence electron AH2 systems. The singlet-triplet splitting (X˜ 3Σg-—ã 1Δg) is predicted to be 53.6 kcal/mol (2.32 eV, 18 700 cm-1), while the X˜ 3Σg-—b˜ 1Σg+ separation is predicted to be 91.1 kcal/mol (3.95 eV, 31 900 cm-1). The vertical double ionization potentials (IPs) from X˜ 1A1 H2O to the X˜ 3B1, 1 1A1, b˜ 1B1, and 2 1A1 states of H2O2+ are predicted within the cc-pVQZ basis to be 40.1, 41.2, 42.6, and 46.1 eV, respectively, in good agreement with recent double-charge-transfer spectroscopic results. The corresponding adiabatic double IPs are 37.0, 39.3, and 41.0 eV to the X˜ 3Σg-, ã 1Δg, and b˜ 1Σg+ states of H2O2+, respectively. The activation barrier to fragmentation of H2O2+ (X˜ 3Σg- H2O2+→3Σ- OH++H+) at the cc-pVQZ CAS-SOCI level is predicted to be 2.1 kcal/mol (0.10 eV, 738 cm-1), and the reaction is exothermic by 126.4 kcal/mol (5.48 eV, 44 210 cm-1), providing a challenge for direct experimental detection of this elusive molecule.

  5. Lawrence Livermore National Laboratory Surface Water Protection: A Watershed Approach

    SciTech Connect

    Coty, J

    2009-03-16

    This surface water protection plan (plan) provides an overview of the management efforts implemented at Lawrence Livermore National Laboratory (LLNL) that support a watershed approach to protect surface water. This plan fulfills a requirement in the Department of Energy (DOE) Order 450.1A to demonstrate a watershed approach for surface water protection that protects the environment and public health. This plan describes the use of a watershed approach within which the Laboratory's current surface water management and protections efforts have been structured and coordinated. With more than 800 million acres of land in the U.S. under federal management and stewardship, a unified approach across agencies provides enhanced resource protection and cost-effectiveness. The DOE adopted, along with other federal agencies, the Unified Federal Policy for a Watershed Approach to Federal Land and Resource Management (UFP) with a goal to protect water quality and aquatic ecosystems on federal lands. This policy intends to prevent and/or reduce water pollution from federal activities while fostering a cost-effective watershed approach to federal land and resource management. The UFP also intends to enhance the implementation of existing laws (e.g., the Clean Water Act [CWA] and National Environmental Policy Act [NEPA]) and regulations. In addition, this provides an opportunity for the federal government to serve as a model for water quality stewardship using a watershed approach for federal land and resource activities that potentially impact surface water and its uses. As a federal land manager, the Laboratory is responsible for a small but important part of those 800 million acres of land. Diverse land uses are required to support the Laboratory's mission and provide an appropriate work environment for its staff. The Laboratory comprises two sites: its main site in Livermore, California, and the Experimental Test Site (Site 300), near Tracy, California. The main site is largely

  6. Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

    NASA Technical Reports Server (NTRS)

    Fisher, John W.; Hogan, John Andrew; Wignarajah, Kanapathipi; Pace, Gregory S.

    2010-01-01

    Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

  7. The significant surface-water connectivity of "geographically isolated wetlands"

    USGS Publications Warehouse

    Calhoun, Aram J. K.; Mushet, David M.; Alexander, Laurie C.; DeKeyser, Edward S.; Fowler, Laurie; Lane, Charles R.; Lang, Megan W.; Rains, Mark C.; Richter, Stephen; Walls, Susan

    2017-01-01

    We evaluated the current literature, coupled with our collective research expertise, on surface-water connectivity of wetlands considered to be “geographically isolated” (sensu Tiner Wetlands 23:494–516, 2003a) to critically assess the scientific foundation of grouping wetlands based on the singular condition of being surrounded by uplands. The most recent research on wetlands considered to be “geographically isolated” shows the difficulties in grouping an ecological resource that does not reliably indicate lack of surface water connectivity in order to meet legal, regulatory, or scientific needs. Additionally, the practice of identifying “geographically isolated wetlands” based on distance from a stream can result in gross overestimates of the number of wetlands lacking ecologically important surface-water connections. Our findings do not support use of the overly simplistic label of “geographically isolated wetlands”. Wetlands surrounded by uplands vary in function and surface-water connections based on wetland landscape setting, context, climate, and geographic region and should be evaluated as such. We found that the “geographically isolated” grouping does not reflect our understanding of the hydrologic variability of these wetlands and hence does not benefit conservation of the Nation’s diverse wetland resources. Therefore, we strongly discourage use of categorizations that provide overly simplistic views of surface-water connectivity of wetlands fully embedded in upland landscapes.

  8. Model for outgassing of water from metal surfaces

    SciTech Connect

    Li, Minxu; Dylla, Fred

    1993-06-01

    Numerous measurements of outgassing from metal surfaces show that the outgassing obeys a power law of the form Q=Q{sub 10}t{sup -alpha}, where alpha is typically near unity. For unbaked systems, outgassing is dominated by water. This work demonstrates that alpha is a function of the water vapor exposure during venting of the system, and the physical properties of the passivation oxide layer on the surface. An analytic expression for the outgassing rate is derived based on the assumption that the rate of water diffusing through the passivation oxide layer to the surface governs the rate of its release into the vacuum. The source distribution function for the desorbing water is assumed to be a combination of a Gaussian distribution centered at the interior surface driven by atmospheric exposure, and a uniform concentration throughout the bulk. We have measured the outgassing rate from a clean stainless-steel (type 304) chamber as a function of water exposure to the chamber surface from <1 to 600 monolayers. The measured outgassing rate data show that alpha tends to 0.5 for low H{sub 2}O exposures and tends to 1.5 for high H{sub 2}O exposures as predicted by the model.

  9. Properties of water surface discharge at different pulse repetition rates

    SciTech Connect

    Ruma,; Yoshihara, K.; Hosseini, S. H. R. Sakugawa, T.; Akiyama, H.; Akiyama, M.; Lukeš, P.

    2014-09-28

    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H₂O₂) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H₂O₂ and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  10. Surface water pesticide modelling for decision support in drinking water production

    NASA Astrophysics Data System (ADS)

    Desmet, Nele; Dams, Jef; Bronders, Jan; Peleman, Gisèle; Verdickt, Liesbeth

    2015-04-01

    The occurrence of pesticides and other contaminants in river systems may compromise the use of surface water for drinking water production. To reduce the cost of removal of pesticides from the raw water, drinking water companies can: search for other raw water sources, invest in water storage capacity to overcome periods with high pesticide concentrations (often related to the application period), or impose measures to reduce the emission of pesticides to surface water (i.e. sustainable application strategies or use restrictions). To select the most appropriate water management options, the costs and effects of the aforementioned actions need to be evaluated. This evaluation requires knowledge on the concentrations and loads of pesticides at the point of drinking water abstraction, as well as insight in the contribution and the temporal variability of different sources or subbasins. In such a case, a modelling approach can assist in generating measurement-based datasets and to compare different scenarios for water management. We illustrate how a modelling approach can provide decision support for water management related to drinking water abstraction from surface water in a catchment that suffers from elevated pesticide concentrations. The study area is a water production center (WPC) located in northwestern Belgium. The WPC abstracts raw water from the river IJzer or from a natural pond and its connected streams. The available quantities as well as the quality of the water vary throughout the year. The WPC uses a reservoir of 3 million m³ to capture and store raw water to overcome periods with limited water availability and/or poor water