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Sample records for fluctuating water levels

  1. Wii mote as hydrological sensor: observation of water level fluctuations

    Science.gov (United States)

    Luxemburg, W.; Hut, R.; Weijs, S.; Hegnauer, M.

    2009-12-01

    The input device of the Nintendo Wii, the Wii-mote offers scientist a multitude of cheap, high quality sensors; ideal for proof of concept testing. For a specific application, i.e. the water level fluctuation in a floating evaporation pan the Wii-mote was tested as the observing device. It is shown that the controller can observe movements with high enough temporal and spatial resolution of up to 4 infrared LED’s to describe water level movements. Floating pans positioned in lakes and reservoirs better represent open water evaporation than evaporation pans installed on land. On the other hand performing water level measurements in a floating pan is more complicated due to movement of the pan and wave activities in the pan. The Wii-mote was mounted on the side of a standard class A-pan and a float was placed in the middle of the pan, with 4 LED’s on top moving along a fixed bar. The information that the Wii-mote wirelessly sends by blue tooth was captured on a laptop. With a MATLAB routine this data was converted into movement of the LED’s relatively to the controller. The observations show that wave activities are nicely captured with a typical spatial resolution smaller than 0.1 mm in our set-up and a temporal resolution of maximum 100 Hz. A frequency domain filter was applied to the observed datasets to obtain average water levels. In our laboratory setting the pan was placed in a large basin with a wave generator. A constant, but small, rate of water was added to the evaporation pan. The average pan levels from the filtered datasets showed systematically lower levels compared to the level without any wave activities. This is a typical effect of waves that occur in shallow basins. However, the added water with rates up to 5 mm/hour were clearly recognized in the filtered datasets which indicates that the Wii-mote is very well capable as a sensor for water level observations.

  2. Study on Level Fluctuation of Twin Roll Strip Caster by Water Modeling

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    According to the principle of similarity theory, a water model of twin roll strip caster was built. The level fluctuation was measured with an ultrasonic level detector. The effect of nozzle design, casting rate, pool depth and nozzles immersion depths on the level fluctuation was studied. And a level fluctuation mathematical model was developed. The experimental results provided a basis to further optimize the nozzle design and technological parameters of twin roll strip caster.

  3. Spatial–Temporal Dynamics of Wetland Vegetation Related to Water Level Fluctuations in Poyang Lake, China

    Directory of Open Access Journals (Sweden)

    Zhiqiang Tan

    2016-09-01

    Full Text Available Hydrological properties are driving forces of wetland systems. The influence of water level fluctuations on vegetation distribution is of growing interest as wetlands are increasingly disturbed by climate change and intensive human activity. Based on time series MODIS (Moderate Resolution Imaging Spectroradiometer imagery from 2000 to 2012, we investigated the spatial–temporal dynamics of wetland vegetation in Poyang Lake using a combined Sen’s slope and Mann–Kendall (MK test approach, and explored their correlations with water level fluctuations in different hydrological periods. The results showed that more than 34% of wetlands at lower elevations of Poyang Lake had experienced an increasing trend in the enhanced vegetation index (EVI, whereas EVI in about 11% of the wetlands at higher elevations decreased significantly. Responses of grassland area extracted from MODIS EVI were found to be more sensitive to water level fluctuations in the southern lakes. The change rate of grassland area decreased with the rising water level during the rising period, but increased with the rising water level during the retreating period. Correlations between grassland area and water level were much weaker in the dry period. In addition, we found fluctuations of the main water body had negligible effect on grassland area since the water level at Xingzi station was below 14 m. These results provide new insights for predicting future changes of wetland vegetation influenced by the ongoing threats from climate change and human activity, and form a foundation for ecosystem management of Poyang Lake.

  4. A simple procedure to model water level fluctuations in partially inundated wetlands

    NARCIS (Netherlands)

    Spieksma, JFM; Schouwenaars, JM

    1997-01-01

    When modelling groundwater behaviour in wetlands, there are specific problems related to the presence of open water in small-sized mosaic patterns. A simple quasi two-dimensional model to predict water level fluctuations in partially inundated wetlands is presented. In this model, the ratio between

  5. Experimental study on pore pressure in rock-soil slope during reservoir water level fluctuation

    Institute of Scientific and Technical Information of China (English)

    LIU; Yuewu; CHEN; Huixin; LIU; Qingquan; GONG; Xin; ZHANG

    2005-01-01

    A test system was developed for measuring the pore pressure in porous media, and a new model was devised for the pore pressure testing in both saturated and unsaturated rock-soil. Laboratory experiments were carried out to determine the pore pressure during water level fluctuation. The variations of transient pore pressure vs. time at different locations of the simulated rock-soil system were acquired and processed, and meanwhile the deformation and failure of the model are observed. The experiment results show that whether the porous media are saturated or not, the transient pore pressure is mainly dependent on the water level fluctuation, and coupled with the variation of the stress field.

  6. Response of littoral macrophytes to water level fluctuations in a storage reservoir

    Directory of Open Access Journals (Sweden)

    Krolová M.

    2013-05-01

    Full Text Available Lakes and reservoirs that are used for water supply and/or flow regulations have usually poorly developed littoral macrophyte communities, which impairs ecological potential in terms of the EU Water Framework Directive. The aim of our study was to reveal controlling factors for the growth of littoral macrophytes in a storage reservoir with fluctuating water level (Lipno Reservoir, Czech Republic. Macrophytes occurred in this reservoir only in the eulittoral zone i.e., the shoreline region between the highest and the lowest seasonal water levels. Three eulittoral sub-zones could be distinguished: the upper eulittoral with a stable community of perennial species with high cover, the middle eulittoral with relatively high richness of emergent and amphibious species present at low cover values, and the lower eulittoral devoid of permanent vegetation. Cover and species composition in particular sub-zones were primarily influenced by the duration and timing of flooding, followed by nutrient limitation and strongly reducing conditions in the flooded organic sediment. Our results stress the ecological importance of eulittoral zone in reservoirs with fluctuating water levels where macrophyte growth can be supported by targeted management of water level, thus helping reservoir managers in improving the ecological potential of this type of water bodies.

  7. Establishment of earth tides effect on water level fluctuations in an unconfined hard rock aquifer using spectral analysis

    CERN Document Server

    Maréchal, Jean-Christophe; Ahmed, Shakeel; Lachassagne, Patrick

    2010-01-01

    Short-interval water level measurements using automatic water level recorder in a deep well in an unconfined crystalline rock aquifer at the campus of NGRI, near Hyderabad shows a cyclic fluctuation in the water levels. The observed values clearly show the principal trend due to rainfall recharge. Spectral analysis was carried out to evaluate correlation of the cyclic fluctuation to the synthetic earth tides as well as groundwater withdrawal time series in the surrounding. It was found that these fluctuations have considerably high correlation with earth tides whereas groundwater pumping does not show any significant correlation with water table fluctuations. It is concluded that earth tides cause the fluctuation in the water table. These fluctuations were hitherto unobserved during manual observations made over larger time intervals. It indicates that the unconfined aquifer is characterised by a low porosity.

  8. Effects of Barometric Fluctuations on Well Water-Level Measurements and Aquifer Test Data

    Energy Technology Data Exchange (ETDEWEB)

    FA Spane, Jr.

    1999-12-16

    The Pacific Northwest National Laboratory, as part of the Hanford Groundwater Monitoring Project, examines the potential for offsite migration of contamination within underlying aquifer systems. Well water-level elevation measurements from selected wells within these aquifer systems commonly form the basis for delineating groundwater-flow patterns (i.e., flow direction and hydraulic gradient). In addition, the analysis of water-level responses obtained in wells during hydrologic tests provides estimates of hydraulic properties that are important for evaluating groundwater-flow velocity and transport characteristics. Barometric pressure fluctuations, however, can have a discernible impact on well water-level measurements. These barometric effects may lead to erroneous indications of hydraulic head within the aquifer. Total hydraulic head (i.e., sum of the water-table elevation and the atmospheric pressure at the water-table surface) within the aquifer, not well water-level elevation, is the hydrologic parameter for determining groundwater-flow direction and hydraulic gradient conditions. Temporal variations in barometric pressure may also adversely affect well water-level responses obtained during hydrologic tests. If significant, adjustments or removal of these barometric effects from the test-response record may be required for quantitative hydraulic property determination. This report examines the effects of barometric fluctuations on well water-level measurements and evaluates adjustment and removal methods for determining areal aquifer head conditions and aquifer test analysis. Two examples of Hanford Site unconfined aquifer tests are examined that demonstrate barometric response analysis and illustrate the predictive/removal capabilities of various methods for well water-level and aquifer total head values. Good predictive/removal characteristics were demonstrated with best corrective results provided by multiple-regression deconvolution methods.

  9. Simulation of Water Level Fluctuations in a Hydraulic System Using a Coupled Liquid-Gas Model

    Directory of Open Access Journals (Sweden)

    Chao Wang

    2015-08-01

    Full Text Available A model for simulating vertical water level fluctuations with coupled liquid and gas phases is presented. The Preissmann implicit scheme is used to linearize the governing equations for one-dimensional transient flow for both liquid and gas phases, and the linear system is solved using the chasing method. Some classical cases for single liquid and gas phase transients in pipelines and networks are studied to verify that the proposed methods are accurate and reliable. The implicit scheme is extended using a dynamic mesh to simulate the water level fluctuations in a U-tube and an open surge tank without consideration of the gas phase. Methods of coupling liquid and gas phases are presented and used for studying the transient process and interaction between the phases, for gas phase limited in a chamber and gas phase transported in a pipeline. In particular, two other simplified models, one neglecting the effect of the gas phase on the liquid phase and the other one coupling the liquid and gas phases asynchronously, are proposed. The numerical results indicate that the asynchronous model performs better, and are finally applied to a hydropower station with surge tanks and air shafts to simulate the water level fluctuations and air speed.

  10. The effects of water-level fluctuations on vegetation in a Lake Huron wetland

    Science.gov (United States)

    Wilcox, D.A.; Nichols, S.J.

    2008-01-01

    The diversity and resultant habitat value of wetland plant communities in the Laurentian Great Lake's are dependent on water-level fluctuations of varying frequency and amplitude. Conceptual models have described the response of vegetation to alternating high and low lake levels, but few quantitative studies have documented the changes that occur. In response to recent concerns over shoreline management activities during an ongoing period of low lake levels in lakes Superior, Michigan, and Huron that began in 1999, we analyzed a quantitative data set from Saginaw Bay of Lake Huron collected from 1988 to 1993 during a previous lake-level decline to provide the needed information on vegetation responses. Transects were established that followed topographic contours with water-level histories that differed across a six-year period, ranging from barely flooded to dewatered for varying numbers of years to never dewatered. Percent cover data from randomly placed quadrats along those transects were analyzed to assess floristic changes over time, document development of distinct plant assemblages, and relate the results to lake-level changes. Ordinations showed that plant assemblages sorted out by transects that reflect differing water-level histories. Distinction of assemblages was maintained for at least three years, although the composition and positioning of those assemblages changed as lake levels changed. We present a model that uses orthogonal axes to plot transects by years out of water against distance above water and sorted those transects in a manner that matched ordination results. The model suggests that vegetation response following dewatering is dependent on both position along the water level/soil moisture gradient and length of time since dewatering. This study provided quantitative evidence that lake-level fluctuations drive vegetative change in Great Lakes wetlands, and it may assist in making decisions regarding shoreline management in areas that

  11. Windows of opportunity for germination of riparian species after restoring water level fluctuations: a field experiment with controlled seed banks

    NARCIS (Netherlands)

    Sarneel, J.M.; Janssen, R.H.; Rip, W.J.; Bender, I.; Bakker, E.S.

    2014-01-01

    Restoration activities aiming at increasing vegetation diversity often try to stimulate both dispersal and germination. In wetlands, dispersal and germination are coupled as water and water level fluctuations (WLF) simultaneously influence seed transport and germination conditions (soil moisture). W

  12. Windows of opportunity for germination of riparian species after restoring water level fluctuations : a field experiment with controlled seed banks

    NARCIS (Netherlands)

    Sarneel, Judith M.; Janssen, Roel H.; Rip, Winnie J.; Bender, Irene M. A.; Bakker, Elisabeth S.

    2014-01-01

    1. Restoration activities aiming at increasing vegetation diversity often try to stimulate both dispersal and germination. In wetlands, dispersal and germination are coupled as water and water level fluctuations (WLF) simultaneously influence seed transport and germination conditions (soil moisture)

  13. A hydro-economic model for water level fluctuations: combining limnology with economics for sustainable development of hydropower.

    Science.gov (United States)

    Hirsch, Philipp Emanuel; Schillinger, Sebastian; Weigt, Hannes; Burkhardt-Holm, Patricia

    2014-01-01

    Water level fluctuations in lakes lead to shoreline displacement. The seasonality of flooding or beaching of the littoral area affects nutrient cycling, redox gradients in sediments, and life cycles of aquatic organisms. Despite the ecological importance of water level fluctuations, we still lack a method that assesses water levels in the context of hydropower operations. Water levels in reservoirs are influenced by the operator of a hydropower plant, who discharges water through the turbines or stores water in the reservoir, in a fashion that maximizes profit. This rationale governs the seasonal operation scheme and hence determines the water levels within the boundaries of the reservoir's water balance. For progress towards a sustainable development of hydropower, the benefits of this form of electricity generation have to be weighed against the possible detrimental effects of the anthropogenic water level fluctuations. We developed a hydro-economic model that combines an economic optimization function with hydrological estimators of the water balance of a reservoir. Applying this model allowed us to accurately predict water level fluctuations in a reservoir. The hydro-economic model also allowed for scenario calculation of how water levels change with climate change scenarios and with a change in operating scheme of the reservoir (increase in turbine capacity). Further model development will enable the consideration of a variety of additional parameters, such as water withdrawal for irrigation, drinking water supply, or altered energy policies. This advances our ability to sustainably manage water resources that must meet both economic and environmental demands.

  14. [Distribution of Mercury in Plants at Water-Level-Fluctuating Zone in the Three Gorges Reservoir].

    Science.gov (United States)

    Liang, Li; Wang, Yong-min; Li, Xian-yuan; Tang, Zhen-ya; Zhang, Xiang; Zhang, Cheng; WANG, Ding-yong

    2015-11-01

    The mercury (Hg) distribution and storage in plants at water-level-fluctuating zone (WLFZ) in the Three Gorges Reservoir were investigated by analyzing the total mercury(THg) and methylmercury ( MeHg) levels in different parts of plants collected from three typical sites including Shibaozhai, Zhenxi and Hanfeng Lake in WLFZ. The results indicated that THg and MeHg concentrations in plants ranged from (1.62 ± 0.57) to (49.42 ± 3.93) μg x kg(-1) and from (15.27 ± 7.09) to (1 974.67 ± 946.10) ng x kg(-1), respectively. In addition, THg levels in different plant parts followed the trend: root > leaf > stem, and similar trend for MeHg was observed with the highest level in root. An obvious spatial distribution was also found with the THg and MeHg levels in plants in Hanfeng higher than those in the same plants in the other two sampling sites (Shibaozhai and Zhenxi), and there was a difference of THg and MeHg storage in plants in various attitudes. The corresponding THg and MeHg storages were 145.3, 166.4, 124.3 and 88.2 mg x hm(-2), and 1.9, 2.7, 3.6 and 3.2 mg x hm(-2) in 145-150, 150-160, 160-170 and 170-175 m attitudes. The accumulation ability of dominant plants in WLFZ for THg (bioaccumulation factor, BAF 1).

  15. Predicting the Water Level Fluctuation in an Alpine Lake Using Physically Based, Artificial Neural Network, and Time Series Forecasting Models

    Directory of Open Access Journals (Sweden)

    Chih-Chieh Young

    2015-01-01

    Full Text Available Accurate prediction of water level fluctuation is important in lake management due to its significant impacts in various aspects. This study utilizes four model approaches to predict water levels in the Yuan-Yang Lake (YYL in Taiwan: a three-dimensional hydrodynamic model, an artificial neural network (ANN model (back propagation neural network, BPNN, a time series forecasting (autoregressive moving average with exogenous inputs, ARMAX model, and a combined hydrodynamic and ANN model. Particularly, the black-box ANN model and physically based hydrodynamic model are coupled to more accurately predict water level fluctuation. Hourly water level data (a total of 7296 observations was collected for model calibration (training and validation. Three statistical indicators (mean absolute error, root mean square error, and coefficient of correlation were adopted to evaluate model performances. Overall, the results demonstrate that the hydrodynamic model can satisfactorily predict hourly water level changes during the calibration stage but not for the validation stage. The ANN and ARMAX models better predict the water level than the hydrodynamic model does. Meanwhile, the results from an ANN model are superior to those by the ARMAX model in both training and validation phases. The novel proposed concept using a three-dimensional hydrodynamic model in conjunction with an ANN model has clearly shown the improved prediction accuracy for the water level fluctuation.

  16. Seepage flow-stability analysis of the riverbank of Saigon river due to river water level fluctuation

    CERN Document Server

    Oya, A; Hiraoka, N; Fujimoto, M; Fukagawa, R

    2015-01-01

    The Saigon River, which flows through the center of Ho Chi Minh City, is of critical importance for the development of the city as forms as the main water supply and drainage channel for the city. In recent years, riverbank erosion and failures have become more frequent along the Saigon River, causing flooding and damage to infrastructures near the river. A field investigation and numerical study has been undertaken by our research group to identify factors affecting the riverbank failure. In this paper, field investigation results obtained from multiple investigation points on the Saigon River are presented, followed by a comprehensive coupled finite element analysis of riverbank stability when subjected to river water level fluctuations. The river water level fluctuation has been identified as one of the main factors affecting the riverbank failure, i.e. removal of the balancing hydraulic forces acting on the riverbank during water drawdown.

  17. Use of MODIS satellite images for detailed lake morphometry: Application to basins with large water level fluctuations

    Science.gov (United States)

    Ovakoglou, George; Alexandridis, Thomas K.; Crisman, Thomas L.; Skoulikaris, Charalampos; Vergos, George S.

    2016-09-01

    Lake morphometry is essential for managing water resources and limnetic ecosystems. For reservoirs that receive high sediment loads, frequent morphometric mapping is necessary to define both the effective life of the reservoir and its water storage capacity for irrigation, power generation, flood control and domestic water supply. The current study presents a methodology for updating the digital depth model (DDM) of lakes and reservoirs with wide intra and interannual fluctuations of water levels using satellite remote sensing. A time series of Terra MODIS satellite images was used to map shorelines formed during the annual water level change cycle, and were validated with concurrent Landsat ETM+ satellite images. The shorelines were connected with in-situ observation of water levels and were treated as elevation contours to produce the DDM using spatial interpolation. The accuracy of the digitized shorelines is within the mapping accuracy of the satellite images, while the resulting DDM is validated using in-situ elevation measurements. Two versions of the DDM were produced to assess the influence of seasonal water fluctuation. Finally, the methodology was applied to Lake Kerkini (Greece) to produce an updated DDM, which was compared with the last available bathymetric survey (1991) and revealed changes in sediment distribution within the lake.

  18. Can mercury in fish be reduced by water level management? Evaluating the effects of water level fluctuation on mercury accumulation in yellow perch (Perca flavescens)

    Science.gov (United States)

    Larson, James H.; Maki, Ryan P.; Knights, Brent C.; Gray, Brian R.

    2014-01-01

    Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake’s watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of the Rainy–Namakan complex (on the border of the United States and Canada) has been linked to water level (WL) fluctuations, presumably through variation in sediment inundation. As a result, Hg contamination of fish has been linked to international regulations of WL fluctuation. Here we assess the relationship between WL fluctuations and fish Hg content using a 10-year dataset covering six lakes. Within-year WL rise did not appear in strongly supported models of fish Hg, but year-to-year variation in maximum water levels (∆maxWL) was positively associated with fish Hg content. This WL effect varied in magnitude among lakes: In Crane Lake, a 1 m increase in ∆maxWL from the previous year was associated with a 108 ng increase in fish Hg content (per gram wet weight), while the same WL change in Kabetogama was associated with only a 5 ng increase in fish Hg content. In half the lakes sampled here, effect sizes could not be distinguished from zero. Given the persistent and wide-ranging extent of Hg contamination and the large number of regulated waterways, future research is needed to identify the conditions in which WL fluctuations influence fish Hg content.

  19. Wetland Ecohydrology: stochastic description of water level fluctuations across the soil surface

    Science.gov (United States)

    Tamea, S.; Muneepeerakul, R.; Laio, F.; Ridolfi, L.; Rodriguez-Iturbe, I.

    2009-12-01

    Wetlands provide a suite of social and ecological critical functions such as being habitats of disease-carrying vectors, providing buffer zones against hurricanes, controlling sediment transport, filtering nutrients and contaminants, and a repository of great biological diversity. More recently, wetlands have also been recognized as crucial for carbon storage in the context of global climate change. Despite such importance, quantitative approaches to many aspects of wetlands are far from adequate. Therefore, improving our quantitative understanding of wetlands is necessary to our ability to maintain, manage, and restore these invaluable environments. In wetlands, hydrologic factors and ecosystem processes interplay and generate unique characteristics and a delicate balance between biotic and abiotic elements. The main hydrologic driver of wetland ecosystems is the position of the water level that, being above or below ground, determines the submergence or exposure of soil. When the water level is above the soil surface, soil saturation and lack of oxygen causes hypoxia, anaerobic functioning of microorganisms and anoxic stress in plants, that might lead to the death of non-adapted organisms. When the water level lies below the soil surface, the ecosystem becomes groundwater-dependent, and pedological and physiological aspects play their role in the soil water balance. We propose here a quantitative description of wetland ecohydrology, through a stochastic process-based water balance, driven by a marked compound Poisson noise representing rainfall events. The model includes processes such as rainfall infiltration, evapotranspiration, capillary rise, and the contribution of external water bodies, which are quantified in a simple yet realistic way. The semi-analytical steady-state probability distributions of water level spanning across the soil surface are validated with data from the Everglades (Florida, USA). The model and its results allow for a quantitative

  20. Analysis of the impact of water level fluctuations on macrophytes in Miyun Reservoir after receiving water transferred by the South-to-North Water Diversion Project

    Science.gov (United States)

    Yu, L.; Gu, H.; Lou, C. H.; Zhang, L.; Meng, Q. Y.

    2016-08-01

    As the main primary producers in aquatic ecosystems, macrophytes affect the structure and function of aquatic ecosystems, and their distribution is controlled by water depth. Miyun Reservoir in Beijing will have to experience substantial changes in water level and surface area as it begins to receive water transferred by the South-to-North Water Diversion Project, which will have an adverse impact on the macrophytes growing there. In this study, a hydrodynamic model was constructed with MIKE21 and then used in a simulation in three scenarios: dry year, normal year and wet year. The results suggest that during water diversion, the annual and interannual water level fluctuations will be too significant for them to adapt and as a result, the original macrophytes in the reservoir tend to die and disappear completely. The area of the zone suitable for macrophyte growth, or suitable growth zone (SGZ), fluctuated. Restricted by the main dam and auxiliary dam to its south, the overall suitable growth zone moved toward the northeast and northwest of the reservoir, with a northeastward movement of its centroid. The distance and path of movement varied between scenarios. After the water diversion was completed, the suitable growth zone shrunk in the three scenarios. It is predicted that the macrophyte species diversity and richness of the reservoir can recover to the levels recorded before water diversion only in dry year. These results suggest that manual interventions should be implemented after water diversion to speed up the natural recovery of aquatic plant communities in Miyun Reservoir and thereby maintain the stability of the aquatic ecosystem.

  1. Water-Level Responses to Barometric-Pressure Fluctuations in Wells in Semi-Confined Aquifers

    Science.gov (United States)

    Jin, W.; Butler, J. J.

    2009-12-01

    Hydrologists have long recognized that changes in barometric pressure can produce changes in water levels in wells. The relationship between barometric pressure and water level has traditionally been characterized using the barometric efficiency (BE), the ratio of the change in water level to the change in barometric pressure head. Although BE has proven to be an effective means of characterizing the short-term response of a well to a change in barometric pressure, the barometric response function (BRF) is a more effective means to characterize the longer-term response. The BRF, which can be determined through a regression deconvolution procedure developed by Rasmussen and co-workers (Rasmussen and Crawford, 1997; Toll and Rasmussen, 2007), characterizes the water level response over time to a step change in barometric pressure, essentially BE as a function of the time since the imposed load. We have extended earlier work of Rasmussen and Spane (Rasmussen and Crawford, 1997; Spane, 2002) to show that the BRF can be utilized to glean important insights into semi-confined aquifer systems. The form of the BRF indicates the degree of aquifer confinement, while a comparison of BRFs from different wells provides insight into aquitard continuity. Recently, we have developed a new approach for estimating aquitard K by fitting type curves to experimentally determined BRFs. We will demonstrate the power of the BRF using field data from a long-term monitoring site of the Kansas Geological Survey at which a four-day pumping test has previously been performed. The aquitard K estimates obtained from the BRFs are in good agreement at this site with the estimate determined from the pumping test. We will also show how the BRF for a well in a semi-confined aquifer can be used to gain insights into conditions in the overlying unconfined aquifer and vadose zone. Although the BE is considered an invariant parameter of a well, we will show that the BRF of a well in a semi

  2. Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Decker-Hess, Janet; Clancey, Patrick (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)

    1984-03-01

    This study was initiated in the fall of 1981 to delineate the extent of successful shoreline spawning of kokanee salmon in Flathead Lake and determine the impacts of the historic and present operations of Kerr and Hungry Horse dams. An investigation of the quantity and quality of groundwater and other factors affecting kokanee reproductive success in Flathead Lake began in the spring of 1982. A total of 719 redds were counted in 17 shoreline areas of Flathead Lake in1983 compared to 592 in 1981 and 1,029 in 1982. Shoreline spawning contributed three percent to the total kokanee spawning in the Flathead drainage in 1983. Fifty-nine percent of the redds were located above 2883 ft, the operational minimum pool. The majority of those redds were constructed between 2885 and 2889 ft. In areas above minimum pool, intergravel dissolved oxygen concentrations were adequate for embryo survival and exhibited a decrease with depth. Limited data indicated apparent velocity may be the key in determining redd distribution. Seventy-five percent of the redds located below minimum pool were constructed in a zone between 2869 and 2883 ft. In individual areas, apparent velocity measurements and intergravel dissolved oxygen concentrations were related to redd density. The variation in intergravel dissolved oxygen concentrations in the Yellow Bay spawning area was partially explained by lake stage fluctuation. As lake stage declined, groundwater apparent velocity increased which increased intergravel dissolved oxygen concentrations. Mean survival to the eyed stage in the three areas below minimum pool was 43 percent. Prior to exposure by lake drawdown, mean survival to the eyed stage in spawning areas above minimum pool was 87 percent. This indicated habitat most conducive to successful embryo survival was in gravels above 2883 ft. prior to significant exposure. Survival in redds exposed to either extended periods of drawdown or to temperatures less than -10% was significantly reduced to

  3. Reasons and Predictions of The Caspian Sea Water Level Fluctuations: Impact of Climate Factors and Man's Activities.

    Science.gov (United States)

    Erlich, M.; Shiklomanov, I.; Yezhov, A.; Georgievsky, V.; Shalygin, A.

    The Caspian Sea - the largest lake in the world - has no connection with the Ocean and is lower than its surface. Fluctuations of the Sea level are very significant: during the period of instrumental observations (since 1830) the level amplitude was 3.78 m with maximum of -25.22 m in 1882 and minimum of -29.00 m in 1978. These fluctuations lead to a great damage for the economy of five countries sharing its coast (Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan). Deep knowledge of hydrological and hydrodynamic Sea regime and scientifically justified forecasts of possible changes in its level, taking into account variability in climate and future climate change, are re- quired for undertaking urgent measures for protection of coastal territories. The inter- national research project CASSEAS, carried out in 1997-2000 within the framework of the INCO-COPERNICUS programme by the scientists of 5 countries: France, Rus- sia, Germany, Turkmenistan and UK, was devoted to these problems. Research made within the Project made it possible to get new precise data on all water balance com- ponents of the Caspian Sea for 1880-1996; moreover, all water balance components for 1940-1996 were computed independently. It was shown that the Sea level fluctua- tions depended on the water balance almost completely. Assessment of possible future runoff changes in the Caspian Sea basin was made using the mathematical model of runoff formation developed at the SHI. Several scenarios from a range of GCMs and on the basis of paleoclimatic reconstructions were used as the models of the future climate for the nearest 3 decades. Besides changes in climate characteristics, three variants were accepted for the future water use in the basins of rivers discharging to the Caspian Sea. All scenarios gave similar results for changes in annual river inflow to the Caspian Sea: its increase would be from 5% to 10% by 2030. The same scenarios, used to estimate changes in precipitation onto the Sea

  4. Water level fluctuations in rich fens: an assessment of ecological benefits and drawbacks

    NARCIS (Netherlands)

    I.S. Mettrop

    2015-01-01

    For the proper functioning of endangered biodiverse rich fens, base-rich and nutrient-poor (mesotrophic) conditions are required to prevent succession towards Sphagnum-dominated peatlands. Unfortunately, water- and soil quality of many European wetlands are negatively affected by changes in hydrolog

  5. Water-level fluctuations in the Black Sea since the Last Glacial Maximum

    OpenAIRE

    Lericolais, Gilles; Popescu, I; F. Guichard; Popescu, S. M.

    2007-01-01

    Two IFREMER oceanographic surveys carried out in the northwestern Black Sea in 1998 and 2002 complement previous seabed mapping and subsurface sampling by various international expeditions. They show that the lake level rose on the continental shelf to at least the -40 to -30 m isobath based on the landward limit of a Dreissena layer representative of very low salinity conditions (

  6. Revegetation impacts soil nitrogen dynamics in the water level fluctuation zone of the Three Gorges Reservoir, China.

    Science.gov (United States)

    Ye, Chen; Cheng, Xiaoli; Liu, Wenzhi; Zhang, Quanfa

    2015-06-01

    Revegetations in riparian ecosystem are important in regulating soil nitrogen (N) dynamics. However, impacts of revegetation on soil N cycling and thereby on ecosystem functioning are not fully understood. We conducted an in situ incubation in the water level fluctuation zone (WLFZ) of the Three Gorges Reservoir region to evaluate soil N transformation including net N mineralization rate, net ammonification rate, net nitrification rate, net denitrification rate, N leaching and plant N uptake as well as the soil inorganic N (NH4(+)-N and NO3(-)-N) concentration in the top soils (0-20 cm) following revegetations (implementing tree, shrub and herb plantations) over two years. The soil inorganic N concentration and N leaching were lower in the tree soils than in herb and shrub soils. Tree plantations decreased net N mineralization rate and net ammonification rate compared to herb and shrub soils, possibly due to lower soil organic carbon (SOC) input and soil temperatures. Whereas tree plantations increased soil net denitrification rate compared to herb and shrub soils because of higher tree NO3(-)-N uptake together with higher net nitrification rate. The inorganic N in the tree and shrub soils were lower in fall and summer, respectively, which was dependent on the seasonal variations in plant N uptake, soil N transformation, and N leaching. Thus, our results suggest that tree plantations could decrease soil inorganic N concentration and N leaching by altering both the quantity and quality of SOC and thereby potentially improve water quality in the riparian zone.

  7. [Effect of Seasonal Temperature Increasing on Nitrogen Mineralization in Soil of the Water Level Fluctuating Zone of Three Gorge Tributary During the Dry Period].

    Science.gov (United States)

    Lin, Jun-jie; Zhang, Shuai; Liu, Dan; Zhou, Bin; Xiao, Xiao-jun; Ma, Hui-yan; Yu, Zhi-guo

    2016-02-15

    To reveal the effect of seasonal temperature increasing on nitrogen mineralization in soil of the water level fluctuating soil zone of three gorge reservoir areas in the Yangtze river tributary during the dry period, surface soils were collected from the water level fluctuating zone of Pengxi river crossing two hydrological sections, i.e., upstream and downstream and three water level altitudes, 155 m (low), 165 m (middle) and 175 m (high). We incubated the soil at 25 degrees C and 35 degrees C to determine the transformation rates of nitrogen in soil of Pengxi river basin during the dry period. The result showed that TN and NO3- -N contents in the soil of upstream section and higher (175 m) altitude of water level were higher than those in downstream and low (165 m) altitude of water level, whereas the pattern for NH4+ -N was different, with higher NH4+ -N contents in downstream and low water level. The inorganic nitrogen was dominated by NO3- -N, which accounted for up to 57.4%-84.7% of inorganic nitrogen. Generally, soil ammoniation, nitration and net N mineralization increased with the rising water level altitude and stream sections (P 0.05).

  8. An Original Processing Method of Satellite Altimetry for Estimating Water Levels and Volume Fluctuations in a Series of Small Lakes of the Pantanal Wetland Complex in Brazil

    Science.gov (United States)

    Henrique Costa, Paulo; Oliveira Pereira, Eric; Maillard, Philippe

    2016-06-01

    Satellite altimetry is becoming a major tool for measuring water levels in rivers and lakes offering accuracies compatible with many hydrological applications, especially in uninhabited regions of difficult access. The Pantanal is considered the largest tropical wetland in the world and the sparsity of in situ gauging station make remote methods of water level measurements an attractive alternative. This article describes how satellites altimetry data from Envisat and Saral was used to determine water level in two small lakes in the Pantanal. By combining the water level with the water surface area extracted from satellite imagery, water volume fluctuations were also estimated for a few periods. The available algorithms (retrackers) that compute a range solution from the raw waveforms do not always produce reliable measurements in small lakes. This is because the return signal gets often "contaminated" by the surrounding land. To try to solve this, we created a "lake" retracker that rejects waveforms that cannot be attributed to "calm water" and convert them to altitude. Elevation data are stored in a database along with the water surface area to compute the volume fluctuations. Satellite water level time series were also produced and compared with the only nearby in situ gauging station. Although the "lake" retracker worked well with calm water, the presence of waves and other factors was such that the standard "ice1" retracker performed better on the overall. We estimate our water level accuracy to be around 75 cm. Although the return time of both satellites is only 35 days, the next few years promise to bring new altimetry satellite missions that will significantly increase this frequency.

  9. [Effect of Soil and Dominant Plants on Mercury Speciation in Soil and Water System of Water-Level-Fluctuation Zone in the Three Gorges Area].

    Science.gov (United States)

    Liang, Li; Wang, Yong-min; Zhang, Cheng; Yu, Ya-wei; An, Si-wei; Wang, Ding-yong

    2016-03-15

    Plentiful plants in the water-level-fluctuation-zone (WLFZ) of Three Gorges Reservoir ( TGR) grow vigorously during the non-flooded period, especially the herbaceous ones. Then, the WLFZ is submerged gradually from the end of September. Soil-plant system that under a long time flooded condition may change the form of mercury, thus resulting in a secondary pollution of the water environment in TGR. To understand the characteristics of mercury species in soils and water after submerged, four kinds of typical plants from TGR were tested in the lab under submerged condition. The results indicated that the plants could promote the formation of soil methylmercury ( MeHg) , and had a significant effect on the different forms of mercury concentrations of the overlying water during inundation. Cynodon dactylon as the dominant species in WLFZ, because of its higher content of total mercury ( THg ) and methylmercury, the effect on MeHg and the other forms of mercury in the soil and the overlying water system was obvious. After 90 days, the soil MeHg level was the highest in Cynodon dactylon & soil & water treatment (B1) [(1,135.86 ± 113.84) ng · kg⁻¹]. It was approximately 2 times less than that of the soil MeHg in soil & water treatment (CK2) . The variation characteristics of total mercury (THg), reactive mercury (RHg) , dissolved mercury (DHg), total methylmercury (TMeHg) and dissolved methylmercury (DMeHg) of overlying water all showed a parabolic shape with a peak skewed to the left, and the peak was reached on the 30th day. Meanwhile, TMeHg, THg and DHg in B1 treatment were the highest, which were (2.88 ± 0.06), (40.29 · 2.42) and (35.51 · 3.77) ng · L⁻¹ respectively, and TMeHg and THg in the overlying water were mainly in the form of dissolved state. Therefore, it could be inferred that the water consumption of the Three Gorges reservoir would increase the mercury pollution load of the reservoir.

  10. Lake level fluctuations boost toxic cyanobacterial "oligotrophic blooms".

    Directory of Open Access Journals (Sweden)

    Cristiana Callieri

    Full Text Available Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii ( = planktonic Anabaena, a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D. lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D. lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms.

  11. Analysis of Water Level Fluctuations and TDS Variations in the Groundwater at Mewat (Nuh District, Haryana (India

    Directory of Open Access Journals (Sweden)

    Priyanka1

    2016-08-01

    Full Text Available Groundwater is the major source for fulfilling the water needs of domestic and agricultural sectors in Mewat district, Haryana, India and its continuous use has put an enormous pressure on the groundwater resource, which along with low rainfall and variable geographical conditions lead to the declining water levels. The other problem of this area is high salinity which is reported intruding to the freshwater zone1. Taking into account the twin problem of declining water level and high salinity the study was taken up jointly by National Institute of Hydrology, Roorkee; Sehgal Foundation, Gurgaon and Indian Institute of Technology, Roorkee. Groundwater level and TDS (Total dissolved solids data for pre-monsoon and post-monsoon seasons for the time period of 2011–2015 of 40 monitoring wells developed by Sehgal Foundation, Gurgaon was collected and analysed. It has been found that the groundwater level is decreasing in the area while TDS values show inconsistent trends during 2011-15. Further monitoring of the wells is continued to get the more information on water level and TDS which will help in facilitating the researchers in finding out the applicable solutions for the above problems in the Mewat, Haryana.

  12. Submergence Tolerance and Germination Dynamics of Roegneria nutans Seeds in Water-Level Fluctuation Zones with Different Water Rhythms in the Three Gorges Reservoir.

    Directory of Open Access Journals (Sweden)

    Feng Lin

    Full Text Available The Three Gorges Dam features two water-level fluctuation zones (WLFZs: the preupland drawdown zone (PU-DZ and the preriparian drawdown zone (PR-DZ. To investigate the vegetation potential of Roegneria nutans in WLFZs, we compared the submergence tolerance and germination dynamics in the natural riparian zone (NRZ, PU-DZ and PR-DZ. We found that the NRZ seeds maintained an 81.3% intactness rate and >91% germination rate. The final seed germination rate and germination dynamics were consistent with those of the controls. Meanwhile, the PU-DZ seeds submerged at 5 m, 10 m, 15 m, and 20 m exhibited intactness rates of 70.5%, 79.95%, 40.75%, and 39.87%, respectively, and >75% germination. Furthermore, the PR-DZ seeds exhibited intactness rates of 22.44%, 61.13%, 81.87%, and 15.36% at 5 m, 10 m, 15 m, and 17 m, respectively, and 80% germination. The germination rates of the intact seeds submerged >10 m were >80%. Finally, the intact seeds germinated quickly in all WLFZs. The high proportion of intact seeds, rapid germination capacity, and high germination rate permit R. nutans seeds to adapt to the complicated water rhythms of the PU-DZ and PR-DZ and indicate the potential for their use in vegetation restoration and recovery. Thus, perennial seeds can be used for vegetation restoration in the WLFZs of large reservoirs and in other regions with water rhythms similar to the Three Gorges Reservoir.

  13. Submergence Tolerance and Germination Dynamics of Roegneria nutans Seeds in Water-Level Fluctuation Zones with Different Water Rhythms in the Three Gorges Reservoir.

    Science.gov (United States)

    Lin, Feng; Liu, Jianhui; Zeng, Bo; Pan, Xiaojiao; Su, Xiaolei

    2016-01-01

    The Three Gorges Dam features two water-level fluctuation zones (WLFZs): the preupland drawdown zone (PU-DZ) and the preriparian drawdown zone (PR-DZ). To investigate the vegetation potential of Roegneria nutans in WLFZs, we compared the submergence tolerance and germination dynamics in the natural riparian zone (NRZ), PU-DZ and PR-DZ. We found that the NRZ seeds maintained an 81.3% intactness rate and >91% germination rate. The final seed germination rate and germination dynamics were consistent with those of the controls. Meanwhile, the PU-DZ seeds submerged at 5 m, 10 m, 15 m, and 20 m exhibited intactness rates of 70.5%, 79.95%, 40.75%, and 39.87%, respectively, and >75% germination. Furthermore, the PR-DZ seeds exhibited intactness rates of 22.44%, 61.13%, 81.87%, and 15.36% at 5 m, 10 m, 15 m, and 17 m, respectively, and 80% germination. The germination rates of the intact seeds submerged >10 m were >80%. Finally, the intact seeds germinated quickly in all WLFZs. The high proportion of intact seeds, rapid germination capacity, and high germination rate permit R. nutans seeds to adapt to the complicated water rhythms of the PU-DZ and PR-DZ and indicate the potential for their use in vegetation restoration and recovery. Thus, perennial seeds can be used for vegetation restoration in the WLFZs of large reservoirs and in other regions with water rhythms similar to the Three Gorges Reservoir. PMID:27031104

  14. Submergence Tolerance and Germination Dynamics of Roegneria nutans Seeds in Water-Level Fluctuation Zones with Different Water Rhythms in the Three Gorges Reservoir.

    Science.gov (United States)

    Lin, Feng; Liu, Jianhui; Zeng, Bo; Pan, Xiaojiao; Su, Xiaolei

    2016-01-01

    The Three Gorges Dam features two water-level fluctuation zones (WLFZs): the preupland drawdown zone (PU-DZ) and the preriparian drawdown zone (PR-DZ). To investigate the vegetation potential of Roegneria nutans in WLFZs, we compared the submergence tolerance and germination dynamics in the natural riparian zone (NRZ), PU-DZ and PR-DZ. We found that the NRZ seeds maintained an 81.3% intactness rate and >91% germination rate. The final seed germination rate and germination dynamics were consistent with those of the controls. Meanwhile, the PU-DZ seeds submerged at 5 m, 10 m, 15 m, and 20 m exhibited intactness rates of 70.5%, 79.95%, 40.75%, and 39.87%, respectively, and >75% germination. Furthermore, the PR-DZ seeds exhibited intactness rates of 22.44%, 61.13%, 81.87%, and 15.36% at 5 m, 10 m, 15 m, and 17 m, respectively, and 80% germination. The germination rates of the intact seeds submerged >10 m were >80%. Finally, the intact seeds germinated quickly in all WLFZs. The high proportion of intact seeds, rapid germination capacity, and high germination rate permit R. nutans seeds to adapt to the complicated water rhythms of the PU-DZ and PR-DZ and indicate the potential for their use in vegetation restoration and recovery. Thus, perennial seeds can be used for vegetation restoration in the WLFZs of large reservoirs and in other regions with water rhythms similar to the Three Gorges Reservoir.

  15. Long transients near the ghost of a stable state in eutrophic shallow lakes with fluctuating water levels

    NARCIS (Netherlands)

    Van Geest, G.J.; Coops, H.; Scheffer, M.; van Nes, E.H.

    2007-01-01

    Alternative stable states in shallow lakes have received much attention over the past decades, but less is known about transient dynamics of such lakes in the face of stochastic perturbations such as incidental extremes in water levels driven by climatic variability. Here, we report on the ecosystem

  16. Fiscal 1998 geothermal development promotion research report on the environmental impact in Akinomiya district. Hot spring, water level, spring water fluctuation; 1998 nendo chinetsu kaihatsu sokushin chosa Akinomiya chiiki chosa kankyo eikyo chosa hokokusho. Onsen, suii, yusui hendo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    This research was made for investigating the impact of geothermal development on hot spring, ground water level and spring water by drilling 3 investigation wells N9-AY-3, N9- AY-4 and N9-AY-5 in Akinomiya district. Some research items for hot spring showed slight fluctuation until 1997, however, those showed no fluctuation due to drilling of the 3 investigation wells in fiscal 1998. These results suggest that drilling of the investigation wells has no effect on the spring and quality of hot water in Akinomiya district. Drilling of N9-AY-4 well is carrying out continuously after Sept. 1998. Fluctuation of ground water levels was dependent on precipitations, however, drilling of the 3 investigation wells has no effect on the ground water level. These results suggest that drilling of the investigation wells has no effect on the spring of hot water in Akinomiya district. Every research item for spring water showed relatively slight fluctuation stably. These results suggest that drilling of the investigation wells has no effect on spring water in Akinomiya district. (NEDO)

  17. Dynamics and consequences of water level fluctuations of selected lakes in the catchment of the Ostrowo-Gopło Channel

    Directory of Open Access Journals (Sweden)

    Piasecki Adam

    2014-12-01

    Full Text Available The article discusses water level fluctuations in lakes and the associated changes in the lake surface and water resources in the years 1992-2011. On the basis of detailed field studies carried out in the hydrological year 2011, short-term and dynamic changes in the lakes’ hydrology were determined. Changes in hydrological lake types were evoked by unexpected hydro-meteorological situations, in particular high precipitation totals and sudden thaws in winter. The main symptom of the lake type change was the restoration, after nearly 10 years, of channels connecting the lakes. In addition, a strong interdependence was recorded in the difference between evaporation and precipitation, as well as the mean annual ranges of lake water levels in the years 1992-2010

  18. Habitat Selection by African Buffalo (Syncerus caffer) in Response to Landscape-Level Fluctuations in Water Availability on Two Temporal Scales

    OpenAIRE

    Emily Bennitt; Mpaphi Casper Bonyongo; Stephen Harris

    2014-01-01

    Seasonal fluctuations in water availability cause predictable changes in the profitability of habitats in tropical ecosystems, and animals evolve adaptive behavioural and spatial responses to these fluctuations. However, stochastic changes in the distribution and abundance of surface water between years can alter resource availability at a landscape scale, causing shifts in animal behaviour. In the Okavango Delta, Botswana, a flood-pulsed ecosystem, the volume of water entering the system dou...

  19. [Sediment risk assessment and heavy metal source analysis in typical country water level fluctuated zone (WLFZ) of the Three Gorges].

    Science.gov (United States)

    Ao, Liang; Lei, Bo; Wang, Ye-Chun; Zhou, Xie; Zhang, Sheng

    2014-01-01

    Typical country WLFZ in Zhongxian located in the core region of the Three Gorges Reservoir was chosen as research subject in this study. In July 2012, sediment samples of WLFZ were collected after dam water level dropped. Heavy metals were analyzed for sediment potential risk assessment and then applied for sources analysis in this area, which supplied basic data for non-point pollutants control. The results showed that As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged in 155-160 m:5.17-14.81, 0.06-0.57, 8.55-20.56, 62.79-93.04, 15.38-60.97, 425.72-782.32, 21.34-48.5, 23.03-43.39 and 57.78-130.10 mg x kg(-1), and 170-175 m: 7.05-12.57, 0.17-0.33, 10.71-18.89, 65.22-92.89, 18.89-42.91, 74.06-774.41, 22.47-42.49, 24.17-29.23, 55.67-103.18 mg x kg(-1), respectively. Index of geo-accumulation (Igeo) suggested the accumulation orders were Cd > Co > Mn > As > Cu > Pb > Zn in 155-160m WLFZ and Co > Mn > Cd > As in 170-175 m WLFZ. Sediment pollution index (SPI) showed that sediments in 155-160 m WLFZ had higher potential risk than that of 170-175 m with the highest risk appeared in 155-166 m WLFZ site located downstream of Zhongxian. In 155-160 m WLFZ, Cr, Cu, Pb and Zn were mainly originated from natural resources, while As, Ni, Cd, Co and Mn were possibly sourced from upland water. In contrast, in 170-175 m WLFZ, Cr, Ni, Pb and Zn in the sediment came from natural resources, while Cd, As, Co, Mn and Cu were probably rooted from both agricultural non-point source and upland water. PMID:24720202

  20. Spatial and seasonal CH4 flux in the littoral zone of Miyun Reservoir near Beijing: the effects of water level and its fluctuation.

    Directory of Open Access Journals (Sweden)

    Meng Yang

    Full Text Available Wetlands, and especially their littoral zones, are considered to be CH4 emissions hotspots. The recent creation of reservoirs has caused a rapid increase in the area of the world's littoral zones. To investigate the effects of water depth and water level fluctuation on CH4 fluxes, and how these are coupled with vegetation and nutrients, we used static closed chamber and gas chromatography techniques to measure CH4 fluxes in the littoral zone of a large reservoir near Beijing, China, from November 2011 to October 2012. We found that CH4 flux decreased significantly along a transect from open water to dry land, from 3.1 mg m(-2 h(-1 at the deep water site to approximately 1.3 mg m(-2 h(-1 at the shallow water site, and less than 0.01 mg m(-2 h(-1 in the non-flooded area. Water level influenced CH4 flux by affecting soil properties including soil redox potential, soil carbon and nitrogen, and bulk density. The largest emission of all was from the seasonally flooded site after a flooding event (up to 21.1 mg m(-2 h(-1, which may have been caused by vegetation decomposition. Submerged sites had greater emissions, while the driest site had lower emissions. Immediately after the monthly measurements had been made, we removed the aboveground vegetation to enable an assessment of the gas transportation per unit of biomass. Removal of biomass decreased emissions by up to 53%. These results indicated the dominant effect of water depth on CH4 flux through effects of soil conditions, plant species composition and distribution. This study suggests that temporally flooded wetlands, including littoral zones, contribute significantly to the global CH4 burden. However, the current challenge is to capture their spatial extent and temporal variation in the fluxes.

  1. Spatial and seasonal CH4 flux in the littoral zone of Miyun Reservoir near Beijing: the effects of water level and its fluctuation.

    Science.gov (United States)

    Yang, Meng; Geng, Xuemeng; Grace, John; Lu, Cai; Zhu, Yi; Zhou, Yan; Lei, Guangchun

    2014-01-01

    Wetlands, and especially their littoral zones, are considered to be CH4 emissions hotspots. The recent creation of reservoirs has caused a rapid increase in the area of the world's littoral zones. To investigate the effects of water depth and water level fluctuation on CH4 fluxes, and how these are coupled with vegetation and nutrients, we used static closed chamber and gas chromatography techniques to measure CH4 fluxes in the littoral zone of a large reservoir near Beijing, China, from November 2011 to October 2012. We found that CH4 flux decreased significantly along a transect from open water to dry land, from 3.1 mg m(-2) h(-1) at the deep water site to approximately 1.3 mg m(-2) h(-1) at the shallow water site, and less than 0.01 mg m(-2) h(-1) in the non-flooded area. Water level influenced CH4 flux by affecting soil properties including soil redox potential, soil carbon and nitrogen, and bulk density. The largest emission of all was from the seasonally flooded site after a flooding event (up to 21.1 mg m(-2) h(-1)), which may have been caused by vegetation decomposition. Submerged sites had greater emissions, while the driest site had lower emissions. Immediately after the monthly measurements had been made, we removed the aboveground vegetation to enable an assessment of the gas transportation per unit of biomass. Removal of biomass decreased emissions by up to 53%. These results indicated the dominant effect of water depth on CH4 flux through effects of soil conditions, plant species composition and distribution. This study suggests that temporally flooded wetlands, including littoral zones, contribute significantly to the global CH4 burden. However, the current challenge is to capture their spatial extent and temporal variation in the fluxes. PMID:24710279

  2. Global Warming and Caspian Sea Level Fluctuations

    CERN Document Server

    Ardakanian, Reza

    2013-01-01

    Coastal regions have a high social, economical and environmental importance. Due to this importance the sea level fluctuations can have many bad consequences. In this research the correlation between the increasing trend of temperature in coastal stations due to Global Warming and the Caspian Sea level has been established. The Caspian Sea level data has been received from the Jason-1 satellite. It was resulted that the monthly correlation between the temperature and sea level is high and also positive and almost the same for all the stations. But the yearly correlation was negative. It means that the sea level has decreased by the increase in temperature.

  3. Responses of N2O flux to water level fluctuation and other environmental factors at littoral zone of Miyun Reservoir: a comparison with CH4 fluxes

    Directory of Open Access Journals (Sweden)

    M. Yang

    2015-04-01

    Full Text Available There have been only a few studies that allow us to estimate the contribution of newly-created reservoirs to greenhouse gas budgets. In particular, information is limited for understanding the spatiotemporal variation of N2O flux and the underlying mechanisms in the littoral zone where complex biochemical processes are induced by water level fluctuations. A study was carried out at five different water levels (deep water area, shallow water area, seasonally flooded area, control site for seasonally flooded area and non-flooded area at the littoral zone of a temperate reservoir using the static chamber technique. Seasonal and spatial variations of N2O flux and environmental factors were monitored throughout the growing season including a flood event during summer rains. The N2O flux ranged from −2.29 to 182.47 μg m−2 h−1. Non-flooded dry land emitted more N2O than flooded land, no matter whether it was permanently or seasonally flooded. However, no significant difference was observed between seasonally flooded sites and their control sites. Wind speed, air temperature, soil water content, dissolved oxygen in water and soil nitrate influenced N2O flux significantly. In order to know the contrasting characteristics of N2O and CH4 fluxes in the littoral zone of the reservoir, results were compared with a previous study on CH4 emission carried out at the same sites and time with comparable methods. It showed that N2O flux and CH4 flux was influenced by distinct factors and in differing ways. This work highlights the complexity of N2O flux at the littoral zone. The different response ways of N2O and CH4 to environments implies the big challenge of greenhouse gas emission control through ecosystem management.

  4. Influence of Reservoir Water Level Fluctuations on Sediment Methylmercury Concentrations Downstream of the Historical Black Butte Mercury Mine, OR

    Science.gov (United States)

    Mercury (Hg) is a pollutant of global concern due to its ability to accumulate as methylmercury (MeHg) in biota. Mercury is methylated by anaerobic microorganisms such as sulfate reducing bacteria (SRB) in water and sediment. Throughout North America, reservoirs tend to have e...

  5. Long-Term, Seasonal and Short-Term Fluctuations in the Water Level of the Southern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Wolski Tomasz

    2014-09-01

    Full Text Available Aim of this work are analyses of oscillations sea levels in the Southern Baltic on a scale of short-term changes, seasonal and long-term (age. The study was based on observational data in different periods time for tide gauges station of the Polish coast. On the example of some storm situations presents the part of the baric wave and the wind in the formation of extreme sea levels. The primary cause of the annual variability of sea levels was the characteristics of the annual and semi-annual oscillations (the annual and semi-annual solar tide. In the work also determined the rate of long-term sea-level rise for the Polish coast.

  6. The Status and Bioremediation Technology of Ecological Environment in Water-level-fluctuating Zone of the Three Gorges Reservoir%三峡水库消落区生态环境现状及生物治理技术

    Institute of Scientific and Technical Information of China (English)

    王迪友; 邓文强; 杨帆

    2012-01-01

    三峡水库消落区具有水淹时间长、消落幅度大、水位涨落节律逆反自然枯洪规律及面积大、生境类型复杂等特点.从三峡水库消落区目前所面临的生态环境问题出发,总结了国内外关于库区生态环境问题及生物治理的研究进展,提出了三峡水库消落区的生物治理方案.%Water-level-fluctuating zone of the Three Gorges Reservoir possesses some specific characters such as long flooding duration, wide-range fluctuation of water level (30 m), reversed flooding time to winter, large area and complex habitat types and so on. Based on the ecological environmental problems of water-level-fluctuating zone of the Three Gorges Reservoir, the ecological environmental problems and research advances on bioremediation technologies of water-level-fluctuating zone of the reservoir at home and abroad were summarized. The bioremediation strategies for water-level-fluctuating zone of the Three Gorges Reservoir were proposed.

  7. [Effects of Citric Acid on Activation and Methylation of Mercury in the Soils of Water-Level-Fluctuating Zone of the Three Gorges.Reservoir].

    Science.gov (United States)

    Qin, Cai-qing; Liang, Li; You, Rui; Deng, Han; Wang, Ding-yong

    2015-12-01

    To investigate effects of the main component of vegetation root exudates-citric acid on activation and methylation of mercury in the soil of water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir area, simulation experiments were conducted by extracting and cultivating soil with different concentrations of citric acid. The results showed that after adding citric acid, the total mercury content in leaching solution before reaching peak were higher than that of the control, and increased with the increase of citric acid concentrations. The maximum amount of mercury complexes increased initially and then reached plateaus with the percentage against the total mercury in soil of 1.03%, 1.67%, 1.99%, 2.47%, 2.68%, 2.73% and 2.73% for different citric acid concentrations (0, 1, 2, 4, 5, 6 and 8 mmol · L⁻¹). In addition, concentrations of methylmercury ( MeHg) in soil remained stable in the first 3 hours, and then increased accompanying with the increasing rate rising with the concentration of citric acid ( besides the control group) . This result indicated that citric acid probably could promote the transformation process from inorganic mercury to MeHg in soil. which increased with the concentration of citric acid.

  8. [Effects of Citric Acid on Activation and Methylation of Mercury in the Soils of Water-Level-Fluctuating Zone of the Three Gorges.Reservoir].

    Science.gov (United States)

    Qin, Cai-qing; Liang, Li; You, Rui; Deng, Han; Wang, Ding-yong

    2015-12-01

    To investigate effects of the main component of vegetation root exudates-citric acid on activation and methylation of mercury in the soil of water-level-fluctuating zone (WLFZ) of the Three Gorges Reservoir area, simulation experiments were conducted by extracting and cultivating soil with different concentrations of citric acid. The results showed that after adding citric acid, the total mercury content in leaching solution before reaching peak were higher than that of the control, and increased with the increase of citric acid concentrations. The maximum amount of mercury complexes increased initially and then reached plateaus with the percentage against the total mercury in soil of 1.03%, 1.67%, 1.99%, 2.47%, 2.68%, 2.73% and 2.73% for different citric acid concentrations (0, 1, 2, 4, 5, 6 and 8 mmol · L⁻¹). In addition, concentrations of methylmercury ( MeHg) in soil remained stable in the first 3 hours, and then increased accompanying with the increasing rate rising with the concentration of citric acid ( besides the control group) . This result indicated that citric acid probably could promote the transformation process from inorganic mercury to MeHg in soil. which increased with the concentration of citric acid. PMID:27011985

  9. [Distribution and Content of Transferable Nitrogen in the Soil of Water Level Fluctuating Zones of Mainstream and Its Tributary of Three Gorges Reservoir Areas During the Dry Period].

    Science.gov (United States)

    2016-03-15

    In order to find the intrinsic correlation between water eutrophication and transformation of nitrogen in soil of water level fluctuating zone (WLFZ) of Three Gorges Reservoir Areas (TGRA), the method of sequential extraction process was applied to analyze the content and distribution characteristics of total transferable nitrogen (TF-N) in the mainstream of Yangtze River (Wanzhou section) and its tributaries of Mixi and Zhuxi River. The results showed that, compared with the main stream, the contents of soil organic matter (SOM) and total nitrogen (TN) were higher, while cation exchange capacity( CEC) and pH value were lower in the tributaries during the dry period. The main species of TF-N in soil was organic matter-sulfide form of nitrogen (OSF-N) in the WLFZ and the content of different TF-N species was in the order of OSF-N > iron-manganese oxide form of nitrogen (IMOF-N) > ion extractable form of nitrogen (IEF-N) > carbonate form of nitrogen (CF-N). The spatial distribution pattern of total TF-N was in the order of Zhuxi River > Mixi Valley > the main stem of Yangtze River. There were no significant differences between IEF-N and OSF-N contents both in the main and tributaries of Yangtze River. The distribution of CF-N and IMOF-N had similar patterns, whereas the TF-N showed a reverse pattern in comparison with the former two species in the main and tributary of Yangtze River, which was a main factor of TF-N differences between the main steam and tributaries of the Yangtze River.

  10. [Three-dimensional Fluorescence Spectral Characteristics of Different Molecular Weight Fractionations of Dissolved Organic Matter in the Water-level Fluctuation Zones of Three Gorges Reservoir Areas].

    Science.gov (United States)

    Chen, Xue-shuang; Jiang, Tao; Lu, Song; Wei, Shi-qiang; Wang, Ding-yong; Yan, Jin-long

    2016-03-15

    The study of the molecular weight (MW) fractions of dissolved organic matter (DOM) in aquatic environment is of interests because the size plays an important role in deciding the biogeochemical characteristics of DOM. Thus, using ultrafiltration ( UF) technique combined with three-dimensional fluorescence spectroscopy, DOM samples from four sampling sites in typical water-level fluctuation zones of Three Gorge Reservoir areas were selected to investigate the differences of properties and sources of different DOM MW fractions. The results showed that in these areas, the distribution of MW fractions was highly dispersive, but the approximately equal contributions from colloidal (Mr 1 x 10³-0.22 µm) and true dissolved fraction (Mr low MW (Mr 1 x 10³-10 x 10³) > medium MW (Mr 10 x 10³-30 x 10³) > high MW (Mr 30 x 10³-0.22 µm). Additionally, with decreasing MW fraction, fluorescence index (FI) and freshness index (BIX) increased suggesting enhanced signals of autochthonous inputs, whereas humification index ( HIX) decreased indicating lowe humification degree. It strongly suggested that terrestrial input mainly affected the composition and property of higher MW fractions of DOM, as compared to lower MW and true dissolved fractions that were controlled by autochthonous sources such as microbial and alga activities, instead of allochthonous sources. Meanwhile, the riparian different land-use types also affected obviously on the characteristics of DOM. Therefore, higher diversity of land-use types, and also higher complexity of ecosystem and landscapes, induced higher heterogeneity of fluorescence components in different MW fraction of DOM. PMID:27337878

  11. Mesoscale wind fluctuations over Danish waters

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, C.L.

    2010-12-15

    Mesoscale wind fluctuations affect the large scale integration of wind power because they undermine the day-ahead predictability of wind speed and power production, and because they can result in large fluctuations in power generation that must be balanced using reserve power. Large fluctuations in generated power are a particular problem for offshore wind farms because the typically high concentration of turbines within a limited geographical area means that fluctuations can be correlated across large numbers of turbines. Furthermore, organised mesoscale structures that often form over water, such as convective rolls and cellular convection, have length scales of tens of kilometers, and can cause large wind fluctuations on a time scale of around an hour. This thesis is an exploration of the predictability of mesoscale wind fluctuations using observations from the world's first two large offshore wind farms - Horns Rev I in the North Sea, and Nysted in the Baltic Sea. The thesis begins with a climatological analysis of wind fluctuations on time scales of 1-10 hours at the two sites. A novel method for calculating conditional climatologies of spectral information is proposed, based on binning and averaging the time axis of the Hilbert spectrum. Results reveal clear patterns between wind fluctuations and locally observed meteorological conditions. The analysis is expanded by classifying wind fluctuations on time scales of 1-3 hours according to synoptic patterns, satellite pictures and wind classes. Results indicate that cold air outbreaks and open cellular convection are a significant contributor to mesoscale wind variability at Horns Rev. The predictability of mesoscale wind fluctuations is tested by implementing standard statistical models that relate local wind variability to parameters based on a large scale weather analysis. The models show some skill, but only achieve a 15% improvement on a persistence forecast. The possibility of explicitly modelling

  12. Fluctuation of Groundwater Levels and Recharge Patterns in Northern Ghana

    Directory of Open Access Journals (Sweden)

    Alexandra Lutz

    2014-12-01

    Full Text Available Evaluating groundwater levels and recharge patterns is part of sustainably managing the water supply and predicting the possibility of water shortages, especially in light of climate change, extreme events (floods/droughts, increasing population and development. In the northern region of Ghana, groundwater is increasingly relied upon as a source of potable water for rural populations, but seasonal and inter-annual fluctuations of groundwater levels and recharge patterns are not always known. The fluctuation of groundwater levels on a seasonal basis shows that groundwater levels at all sites increase in response to seasonal precipitation. On an annual basis, all sites show an overall net decline of groundwater levels over the study period, which may be associated with below-average departures of precipitation during five of the seven study years. The variability of recharge patterns among five sites is attributed to the spatio-temporal variability of precipitation and hydrogeologic site uniqueness. The overarching potential benefit of this study is to facilitate closing knowledge gaps and contribute to a foundation for a more robust evaluation of groundwater resources in the area, especially as more data become available.

  13. Spatial patterns of zooplanktivore Chirostoma species (Atherinopsidae during water-level fluctuation in the shallow tropical Lake Chapala, Mexico: seasonal and interannual analysis

    Directory of Open Access Journals (Sweden)

    Rodrigo Moncayo-Estrada

    2011-01-01

    Full Text Available This study addresses the influence of water-level fluctuations on fish distribution at two temporal scales: seasonal (dry and rainy and interannual (low and high volume conditions. The analysis of abundance relationships among three zooplanktivore Chirostoma species at fifteen sites in Lake Chapala, Mexico, revealed the significant influence of contrasting conditions (P=0.0002. Seasonally, segregation was more related to species dominance in the dry season and exclusively related to environmental characteristics in the rainy season. Interanually, biotic influence occurred in the shallowest and the deepest episodes of the lake. Environmental characteristics influenced species distribution when the lake reached 25% of its volume. Site, depth, temperature, and salinity were the leading factors influencing fish distribution. These results emphasize the necessity to implement different management strategies according to lake volume, particularly when a critical threshold is reached.El presente estudio describe la influencia que tiene la fluctuación del nivel del agua en la distribución de los peces a dos diferentes escalas: estacional (estiaje y lluvias e interanual (condiciones de bajo y alto volumen. El análisis de las relaciones de abundancia entre tres especies zooplanctófagas de Chirostoma en quince sitios del Lago de Chapala, México, reveló una influencia estadísticamente significativa en las condiciones contrastantes (P=0.0002. Estacionalmente, la segregación estuvo más relacionada a la dominancia de las especies en la época de estiaje y exclusivamente relacionada a las características ambientales en la época de lluvias. Interanualmente, la influencia biótica se presenta en los episodios más someros y más profundos del lago. Las características ambientales influenciaron la distribución de las especies cuando el lago alcanzó el 25% de su volumen. El sitio geográfico, profundidad, temperatura y salinidad fueron los principales

  14. 三峡库区消涨带植被恢复策略%Revegetation Strategies for Water-Level Fluctuation Zone of the Three Gorges Reservoir Region

    Institute of Scientific and Technical Information of China (English)

    卢志军; 江明喜

    2012-01-01

    After the full functioning of the Three Gorges Dam (TGD) , the hydrologic regime will be markedly changed and most of the pre-dam vegetation in the new Water-Level Fluctuation Zone ( WLFZ) may fail to persist. How to revegetate WLFZ of the Three Gorges Reservoir Region (TGRR) has become a hot topic for the scientific community and the governments. Based on review of scientific literature and the findings of our research, we here bring forward a scheme addressing strategies for revegetation of WLFZ of TGRR. Firstly, monitor vegetation dynamics based on permanent plots along the Three Gorges upstream from TGD, potentially providing suitable plants for the future revegetation plans. Secondly, examine the potential of soil seed bank for revegetation of the above-ground vegetation, and evaluate self-regeneration of the post-dam vegetation. Based on these data, select suitable plants for revegetation that integrate desirable physiological and life-history traits. Specifically, wetland vegetation could be constructed with lotus ( Nelumbo nucifera) and aquatic plants. For sites with gentle terrain and fairly hospitable soil conditions, vertical planting of trees, shrubs and grasses/forbs along the elevation gradient could be considered. To attain the sustainable vegetation cover, the newly artificial vegetation should be monitored for at least 5 years.%三峡工程全面运行之后,水文条件发生巨大变化,新形成的消涨带(海拔145~ 175 m)原有植被大部分可能逐渐消亡.如何重建该地段植被成为科研人员和管理部门关注的热点问题.在文献综合分析的基础上,结合在三峡消涨带植被重建方面的前期工作,建议如下:首先对库区消涨带植被进行长期定位监测,了解新的水文条件下原有植被动态及命运,同时为消涨带植被人工重建提供备选物种;其次,评价土壤种子库恢复地上植被的潜力,结合地上植被监测结果,评价消涨带植被的自我恢复(更新)能

  15. Analysis of jitter due to call-level fluctuations

    NARCIS (Netherlands)

    Mandjes, M.R.H.

    2005-01-01

    In communication networks used by constant bit rate applications, call-level dynamics (i.e., entering and leaving calls) lead to fluctuations in the load, and therefore also fluctuations in the delay (jitter). By intentionally delaying the packets at the destination, one can transform the perturbed

  16. Water-levels fluctuations in a borehole at the Royal Observatory of Belgium: Effects on local gravity, Earth tidal, and barometric responses

    Science.gov (United States)

    Delcourt-Honorez, M.

    A borehole was drilled at the Royal Observatory of Belgium in Brussels, next to the superconducting gravimeter. Three aquifers belong to the 'multiple aquifer-aquitard system'. Continuously since Jun. 1984, various kinds of water levels variations are registered: long term and short term variations and, in the intermediate and deep wells, periodic tidal oscillations. Moreover, the water table and the pressure heads respond to the atmospheric pressure variations. The water levels variations perturbing effects in the superconducting gravimeter registrations are estimated and the hydraulic problem and the consolidation problem are studied. The classical Bouguer's formula in theories is enlarged, taking into account the nature of the layers, the expansions or compressions of each layer, the global land surface displacement and the various hydrostatic occurrences of phases on porous media. The Bouguer's theory is also extended to the case of a finite thickness layer, by a numerical integration. The water levels variations in the intermediate and deep aquifers (at long term, at short term, and the barometric and tidal responses) are only inducing negligible perturbing effects on the superconducting gravimeter registrations but the effect of the water table drift is at the limit of the actual precision of the gravimeter registrations. On the other hand, the barometric and tidal responses of the well-aquifer systems are used to estimate the in situ parameters of both the aquifers and the aquifer system (porosity, specific storage, vertical compressibility, and permeability). The estimated values are in good agreement with those deduced by using hydrogeological, soil, and rock mechanics considerations. The research presented can be applied to any hydrogeological configuration with any complexity.

  17. Change of Heavy Metals Content in Soil of Water-Level-Fluctuating Zone in Three Gorges Reservoir Area%三峡库区消落带土壤重金属含量变化特征研究

    Institute of Scientific and Technical Information of China (English)

    王图锦; 杨清伟; 潘瑾; 刘雪莲

    2013-01-01

    采集三峡库区消落带土壤,对干湿交替运行下消落带土壤重金属迁移转化特征进行研究.结果表明:汛期水体重金属含量明显高于汛后,消落带土壤重金属的迁移转化引起的环境风险较低.消落带土壤Cu和Cr主要以残渣态存在,生态风险较低,Pb和Cd可提取态重金属含量较高,潜在生态风险较大.长期周期性干湿交替运行下消落带土壤重金属含量总体呈现增加趋势,土壤中Cu,Pb,Cd,Cr的含量分别提高了17.04%,24.49%,12.99%及13.70%,总体而言,增大幅度排序为Pb >Cu >Cr>Cd.%Taking the soil of water-level-fluctuating zone in Three Gorges Reservoir area as the research object,the features of migration and transportation of the heavy metals in the soil of water-level-fluctuating zone in the condition of alternate drying-wetting are studied.The results indicate that the content of heavy metals in water in flood season is higher than that after the flood season.The environmental risk caused by migration and transportation of the heavy metals in the soil of waterlevel-fluctuating zone is low.Cu and Cr in soil of water-level-fluctuating zone exist in the form of residue and the ecological risk is low.Heavy metals could be extracted from Pb and Cd,whose potential ecological risk is high.Heavy metal concentration inclines to increase generally in a periodical alternate drying-wetting environment for a long time.The average increasing amount of Cu,Pb,Cd and Cr is 17.04%,24.49%,12.99%,13.70% respectively.In general,the increment sequence is Pb > Cu > Cr > Cd.

  18. CHANGES IN SEDIMENTATION AND AQUATIC VEGETATION CAUSED BY DRASTIC LAKE-LEVEL FLUCTUATION

    Directory of Open Access Journals (Sweden)

    Tiit VAASMA

    2015-06-01

    Full Text Available This study identifies the water-level fluctuation signals from the lake sediment. The water level of small Lake Martiska (Estonia decreased 3.4 m from 1946 to 1987 and only 29% of lake area and 21% of total volume remained. Since the 1990s the water level started to rise. The comparison between the LOI, grain-size distribution and documented water-level changes suggests that sign of water-level fluctuation in clearly reflected in sediment cores from the transportation and accumulation area. Regression causes the coarse-grained sediment transportation to the deepest area of the lake, but the transgression leaves a different pattern – when the lake level recovers, the connection with the previously available near-shore sand is still missing and only the previously reworked material can be transported to deeper area. During the water-level fluctuation period the accumulated sediments originate from two main sources: previously accumulated lacustrine sediments and the glaciolacustrine nearshore sands. The water-level fluctuation has also affected the ecology of the lake. Previously oligotrophic lake is now mesotrophic and the rare characteristic species for oligotrophic lakes such as Isoëtes lacustris L. and Lobelia dortmanna L. have disappeared.

  19. Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake; Effects of Operation of Kerr and Hungry Horse Dam on Reproductive Success, 1983 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Decker-Hess, Janet; McMullin, Steve L.

    1983-11-01

    Koktneesalmon (Oncorhvnchusnerka), the land-locked form of sockeye salmon, were originally introduced to Flathead Lake in 1916. My 1933, kokanee had become established in the lake and provided a popular summer trolling fishery as well as a fall snagging fishery in shoreline areas. Presently, Flathead Lake supports the second highest fishing pressure of any lake or reservoir in Montana (Montana Department of Fish and Game 1976). During 1981-82, the lake provided 168,792 man-days of fishing pressure. Ninety-two percent of the estimated 536,870 fish caught in Flathead Lake in 1981-82 were kokanee salmon. Kokanee also provided forage for bull trout seasonally and year round for lake trout. Kokanee rear to maturity in Flathead Lake, then return to various total grounds to spawn. Spawning occurred in lake outlet streams, springs, larger rivers and lake shoreline areas in suitable but often limited habitat. Shoreline spawning in Flathead Lake was first documented in the mid-1930's. Spawning kokanee were seized from shoreline areas in 1933 and 21,000 cans were processed and packed for distribution to the needy. Stefanich (1953 and 1954) later documented extensive but an unquantified amount of spawning along the shoreline as well as runs in Whitefish River and McDonald Creek in the 1950's. A creel census conducted in 1962-63 determined 11 to 13 percent of the kokanee caught annually were taken during the spawning period (Robbins 1966). During a 1981-82 creel census, less than one percent of the fishermen on Flathead Lake were snagging kokanee (Graham and Fredenberg 1982). The operation of Kerr Dam, located below Flathead Lake on the Flathead River, has altered seasonal fluctuations of Flathead Lake. Lake levels presently remain high during kokanee spawning in November and decline during the incubation and emergence periods. Groundwater plays an important role in embryo and fry survival in redds of shoreline areas exposed by lake drawdown. Stefanich (1954) and

  20. Analysis of Influence of Reservoir Water Level Fluctuation on Stability of a Bank Slope%水库水位变化对某岸区公路边坡稳定性影响分析

    Institute of Scientific and Technical Information of China (English)

    周群华; 闫澍旺; 邓卫东; 熊伟

    2011-01-01

    The road in mountain area is always built beside reservoir. The water level will change when storing water or discharging water, which will influence the slope stability. Based on a certain bank slope project, the influence of water level fluctuation, decrease velocity, soil permeability, and excess pore water pressure on stability of slope was analyzed through seepage field calculating and strength reduction calculating with soft ware Plaxis. It is shown that ( 1 ) when the soil condition is set to be drained, the stability factor of slope becomes decrescent and then increseent with the increase or decrease of the reservoir water level, i. e. ,there is a special water level at which the stability factor of slope would be minimal; (2) with the decrease of the water level, the stability factor of slope on the undrained situation of soil would decrease 10% contrasted with that on the drained situation of soil; (3) the faster the water level decrease or the smaller the permeability coefficient of soil , the worse to the stability of the slope.%山区公路经常沿水库修筑,水库的蓄水与放水能引起水位的循环升降变化.水位变化对边坡稳定有较大影响.基于Plaxis有限元软件的渗流计算和边坡稳定的强度折减法计算功能,以一个实际库岸边坡为算例,分析了水位升降变化及下降速率、土体渗透系数、是否考虑超孔隙水压力对边坡稳定性的影响.分析结果表明,当土体设置为排水条件时,不管水位升还是降,边坡稳定系数都先减小,后又上升,即都存在一个使边坡稳定系数最小的水位.随着水位下降,土体设置为不排水条件下坡体内产生的超孔隙水压力导致的边坡稳定系数比排水条件下约低10%左右.水位下降速率越大、土体渗透系数越小,越不利于边坡稳定.

  1. 水位变化条件下波浪侵蚀坡面微地貌演变过程%Changing Process of Microtopography on Slope During Wave-induced Erosion under Water Level-Fluctuation Conditions

    Institute of Scientific and Technical Information of China (English)

    徐胜; 刘刚; 许文年; 夏振尧; 操佩

    2013-01-01

    Abstract A large number of reservoirs were formed due to the construction of hydraulic projects.The regulating and controlling water resources caused water level fluctuation.Under this condition,the process of waveinduced erosion on the reservoir bank was very different from the situation of the fixed water level.In this paper,a flume simulation experiment was used to study the wave-induced erosion on the slope of 20℃,when the water level is rising,falling and fixed.The results show that the wave-induced erosion is apparently different among different water level fluctuation conditions.When the water level is falling,the main erosion happens after 15-30 minutes; and the soil erosion on slope central part is the most serious.Whereas,during the water level is rising or fixed,the most serious soil erosion happens on upper and central parts of slope.Under different water level changing conditions,soil erosion rates on the slope is fast at early stage and slow at late stage.Affection of water tongue is one of the most important factors to the soil slope erosion.When the pro tection component is used on the reservoir bank,the way to reduce the clapping strength of water tongue on the slope could be considered.%大量水利工程的修建形成大量的水库,由于水利工程有调控水资源的需要,水位涨落在所难免,这种条件下波浪对库岸的侵蚀与水位固定时必然不同.利用水槽模拟试验,研究水位在涨、落以及固定时波浪对20℃边坡的侵蚀.结果表明,水位涨落时与水位固定时波浪侵蚀过程有明显不同.水位下落时15~30 min为主要侵蚀时间段,中部土体侵蚀严重,水位上涨和固定时中上部土体侵蚀严重.3种水位条件下,侵蚀率都呈现先快后慢的趋势.水舌作用是波浪侵蚀的重要因素之一.当对库岸进行构件保护时,可考虑以消减水舌拍击坡面的力量为主要手段.

  2. Patterns of Soil Conservation and Revetment by District at Water-Level-Fluctuating Zone in Three Gorges Reservoir%三峡库区消落带分区固土护岸模式

    Institute of Scientific and Technical Information of China (English)

    高进长; 鲍玉海; 贺秀斌; 唐强; 钟荣华

    2014-01-01

    三峡库区消落带是库区陆域与水库之间生态过渡的缓冲带,在生态系统中发挥着极重要的作用,也是生态系统极度脆弱的地区之一。保护三峡水库,使三峡工程有效运转,是该地区生态环境保护的当务之急。本文以消落带为研究对象,依据消落带功能及生态环境特点,论述了植被恢复与重建对消落带固土护岸的重要性,总结了固土护岸的植被技术及其与小型工程措施相结合的治理方法,并因地制宜地提出了消落带分区固土护岸模式,以期促进该模式的推广和应用,从而为长江三峡库区消落带的生态恢复与重建提供经验及技术支撑。%As the riparian buffer of ecotone between land and reservoir,the water-level-fluctuating zone in the Three Gorges Reservoir not only plays a significantly important role in the ecosystem,but also is the serious fragile zone of the ecosystem. It is imperative to protect local ecological environment through preserving the Three Gorges Reservoir and further ensuring the effective operation of the Three Gorges Project.According to the characteristics and functions of the water-level-fluctua-ting zone,and taking water-level-fluctuating zone as research object,the necessity of restoration and reestablishment of the vegetation to soil conservation and revetment,and further the methods of combining corresponding plantation technique and small engineering measures are studied.Finally,the patterns of soil conservation and revetment adjusted to local conditions are put forward.Concluded above,it is hoped that the ecosystem will be restorated and reconstruced in the water-level-fluc-tuating zone of Three Gorges Reservoir Area by applying soil and revetment technique.

  3. Glacier fluctuations, global temperature and sea-level change

    NARCIS (Netherlands)

    Leclercq, P.W.

    2012-01-01

    The current world-wide glacier retreat is a clear sign of global warming. In addition, glaciers contribute to sea-level rise as a consequence of the current retreat. In this thesis we use records of past glacier fluctuations to reconstruct past climate variations and the glacier contribution to sea-

  4. 地下水位变化对盾构隧道的影响研究%Study on Influence of Water Level Fluctuation on Shield-bored Tunnel

    Institute of Scientific and Technical Information of China (English)

    李春良; 王勇; 张巍

    2012-01-01

    A finite element model of shield-bored tunnel structure is established, so as to study the influence of water level fluctuation on shield-bored tunnel. The deformation of the tunnel and the ground under different water levels can be predicted and the displacement rules of the shield-bored tunnel under different water levels can be revealed by means of the model. The study results show that : 1 ) Rebound deformation will occur to the shallow soil layers at the ground sur- face when the water level rises. The rebound value of ground under which shield-bored tunnel exists is smaller than that of ground under which no shield-bored tunnel exists. 2) Vertical displacement of the tunnel structure and lateral dis- placement of the sidewall will happen when the ground water level rises from the invert to the crown. The higher the ground water level, the bigger the displacement value.%为研究地下水位变化对盾构隧道结构的影响,利用有限元理论,建立了地下水位变化时盾构隧道结构的有限元模型,该模型可预测出不同地下水位时盾构隧道及地面变形情况,揭示出不同水位时的盾构隧道在土中的位移变化规律。结果表明:地下水位发生变化会对盾构隧道产生一定的影响。地下水位上升会导致地表浅层土体发生回弹变形,并且下方有盾构隧道的地表的回弹值要比下方没有盾构隧道的地表的回弹值小;当地下水位从盾构隧道拱底处逐渐升高到中心处和拱顶处时,盾构隧道结构会出现竖向位移和边壁的侧向位移,并且水位越高,隧道的竖向位移和边壁的侧向位移越大。

  5. Fluctuating lake levels in humid climates: a suitable proxy of past precipitation?

    Science.gov (United States)

    Theuerkauf, Martin; Küster, Mathias; Kaiser, Knut

    2016-04-01

    Precipitation is a fundamental climate parameter essentially in arid and semi-arid climates, but changes in precipitation may have influenced Holocene vegetation development and human occupation in humid climates as well. However, past precipitation is notoriously difficult to reconstruct because the proxies available are widely imprecise. For example, peatland proxies such as testate amoebae are suited to reconstruct wet and dry periods of the local environment but they are poorly suited to quantify precipitation. In contrast, lake levels potentially provide a closer link to the past precipitation. In our case study, isolated lakes in the Schorfheide area (NE-Germany), fed by groundwater and rain, show at present prominent water level fluctuations that are closely correlated to annual to decadal changes in precipitation. But are these lakes indeed suitable archives to reconstruct past precipitation? To answer this question we have cored two small lakes in that area (Warnitzsee, Briesensee) with water level fluctuations well above 3 m over the past 40 years. We took seven cores along two transects from the lake shore towards the centre in Lake Warnitzsee and one core near the shore in Lake Briesensee. Core lengths range from 2.5 m to 10 m. Analysis of the cores includes geochemical parameters and pollen analysis. Two cores were dated by radiocarbon ages. All cores show recurrent marked shifts in sediment composition with up to seven peat-gyttia alternations. These sediment shifts indicate that both lakes have strongly fluctuated over the Holocene, partly with a larger magnitude than today. However, whereas the modern fluctuation periods (low and high stands) occurred over years to a few decades, we so far could only detect past fluctuation periods that lasted centuries to millennia. Furthermore, the water level in Lake Warnitzsee possibly followed a long-term trend of high water levels in the early Holocene (10.500-9000 cal. BP), low water levels between 8000 and

  6. Mesoscale wind fluctuations over Danish waters

    DEFF Research Database (Denmark)

    Vincent, Claire Louise

    in generated power are a particular problem for oshore wind farms because the typically high concentration of turbines within a limited geographical area means that uctuations can be correlated across large numbers of turbines. Furthermore, organised mesoscale structures that often form over water......, such as convective rolls and cellular convection, have length scales of tens of kilometers, and can cause large wind uctuations on a time scale of around an hour. This thesis is an exploration of the predictability of mesoscale wind uctuations using observations from the world's rst two large oshore wind farms...... indicate that cold air outbreaks and open cellular convection are a signicant contributor to mesoscale wind variability at Horns Rev. The predictability of mesoscale wind uctuations is tested by implementing standard statistical models that relate local wind variability to parameters based on a large scale...

  7. Free product recovery at spill sites with fluctuating water tables

    International Nuclear Information System (INIS)

    Spills and leaks of hydrocarbons from underground storage tanks, pipelines and other facilities pose a serious potential for groundwater contamination which can be very costly to remediate. The severity of the impacts and the cost of remediation can be reduced by various means. Lateral spreading of free phase hydrocarbons on the groundwater table can be prevented by pumping water to control the hydraulic gradient. Recovery of floating product may be performed by skimming hydrocarbons from wells, usually in combination with water pumping to increase the gradient. The environmental variables (water table gradient, water table fluctuations due to regional recovery wells, rates of water pumping)

  8. [Effect of Low Molecular Weight Organic Acids on the Chemical Speciation and Activity of Mercury in the Soils of the Water-Level-Fluctuating Zone of the Three Gorges Reservoir].

    Science.gov (United States)

    You, Rui; Liang, Li; Qin, Cai-qing; Deng, Han; Wang, Ding-yong

    2016-01-15

    To investigate the effect of low molecular weight organic acids ( LMWOA) on the ability of migration and the species of mercury in the soil of the Water-Level-Fluctuating Zone of the Three Gorges Reservoir, citric acid, tartaric acid and oxalic acid were dded into the soil to conduct simulation experiments. The results showed that the percentage of exchangeable mercury increased with the increase of the concentration of citric acid, but the value declined slightly as the concentration of tartaric acid and oxalic acid increased. While all three acids elevated the bioavailability of mercury, which increased with the increase of the concentration of acids. Vhen the concentration of citric acid reached 15 mmol x L(-1), the activation effect was the best. But for oxalic acid and citric acid, 10 mmol x L(-1) was the optimal concentration. In general, the effect of three organic acids on the activation of mercury in the soil followed the trend of citric acid > tartaric acid > oxalic acid. In the soil supplemented with 15 mmol x L(-1) citric acid, the change of mercury pecies was more and more striking with the prolonged incubation, and the conversion did not stop until 14 d, at that time the stomach cid dissolved mercury increased obviously, which was mainly converted from elemental mercury. PMID:27078955

  9. Fluctuations of fresh-saline water interface and of water table induced by sea tides in unconfined aquifers

    Science.gov (United States)

    Levanon, Elad; Shalev, Eyal; Yechieli, Yoseph; Gvirtzman, Haim

    2016-10-01

    This study examines effects of tides on fluctuations of the fresh-saline water interface and the groundwater level in unconfined coastal aquifers using a two-dimensional numerical model. The time-lags of the simulated hydraulic heads and salinities fluctuations compared to sea level fluctuations are analyzed using cross-correlation analysis. The results show that both the fresh-saline water interface and the groundwater level are affected harmonically by sea tide fluctuations. However, significantly different time-lags are obtained between the hydraulic head in the deeper and upper parts of the aquifer, and between head and salinity in the fresh-saline water interface. The hydraulic head in the deeper part of the aquifer responses much faster to sea level fluctuations than in the upper part. Surprisingly, a similar difference is detected between the time-lag of the hydraulic head in the fresh-saline water interface and the time-lag of the salinity at the same location. Furthermore, the time-lag of the salinity in the fresh-saline water interface is similar to the time-lag of the water table. We suggest a comprehensive mechanism for tidal influence on the coastal groundwater system, in which two main processes act simultaneously. First, sea tide causes a pressure head wave which propagates into the saturated zone of the aquifer, governed by the diffusivity of the aquifer (Ks/Ss). Second, this pressure head wave is attenuated at the water table due to the unsaturated flow within the capillary fringe which occurs during groundwater level oscillations. Because the tidal forcing acts on the sea-floor boundary and the attenuation of the groundwater level due to capillary effect acts on the groundwater table, two dimensional distributions of time-lag and hydraulic head amplitude are created. The capillary effect in the unsaturated zone plays a key role not only in the water table fluctuations as shown previously, but also on the salinity fluctuations in the fresh

  10. Measuring water storage fluctuations in lake Dongting, China, by Topex/Poseidon satellite altimetry.

    Science.gov (United States)

    Zhang, Jiqun; Xu, Kaiqin; Yang, Yonghui; Qi, Lianhui; Hayashi, Seiji; Watanabe, Masataka

    2006-04-01

    Although satellite radar altimetry was developed and optimized for open oceans, it has been used to monitor variations in the level of inland water-bodies such as lakes and rivers. Here, for the first time, we have further used the altimetry-derived variation of water level for estimating the fluctuation of water storage as an addition to the present in situ water storage estimation systems to be used in remote areas and in emergency situation such as in the events flooding monitoring and for studying the effect of climate change. Lake Dongting, the second largest lake in China, influenced frequently by flooding, was, therefore, chosen to demonstrate the potential of the technique. By using the concept of an "assumed reference point", we converted Topex/Poseidon satellite altimetry data on water level variations in Lake Dongting to "water level" data. The "water level" time-series data and in situ water storage were used to establish a rating curve. From the rating curve, we converted data on "water level" derived from seven years (1993-1999) of Topex/Poseidon data to actual water storage in Lake Dongting. The result reveals that the seasonal and annual fluctuations of water storage occurred during the 1990s with a more frequent flooding at the late 1990s' especially the flooding in whole catchment level in 1998 and 1999. The study supports the usefulness of satellite altimetry for dense and continuous monitoring of the temporal variations in water dynamic in moderate to large lakes. PMID:16502025

  11. Coupling water table fluctuation to mercury speciation and transport in wetland ecosystems

    Science.gov (United States)

    Branfireun, B. A.; Mitchell, C. P.

    2008-12-01

    Hydrological processes exert a first-order control over both the conditions required for mercury methylation to occur, and the transport of methylmercury from sites of production. In the recent literature, evidence has been presented that a relationship exists between water level fluctuation and mercury levels in aquatic organisms. These observations have led to the conclusion that this fluctuation is stimulating mercury methylation in littoral sediments and wetland ecosystems through the creation of favourable biogeochemical conditions. Using data from a range of wetland ecosystems, and several experiments that subjected wetland soils to fluctuating water levels, a relationship between water table fluctuation frequency and methylmercury production will be presented. Experimental data show that longer frequency wetting and drying periods result in greater methylmercury production relative to a static or high frequency fluctuation. It was also found that mercury methylation processes in wetland soils are able to sustain elevated pore water concentrations over repeated wetting and draining events. These data suggest that methylmercury export from wetlands is likely limited by the degree of hydrological connectivity rather than biogeochemical processes, highlighting the need to better understand the nature of hydrological linkages among wetlands and adjacent ecosystems.

  12. Fluctuations in Water and their Relation to the Hydrophobic Effect

    OpenAIRE

    Varilly, Patrick Stephen

    2011-01-01

    The hydrophobic effect, or the tendency for oil and water not to mix, is a fundamental force that strongly influences the shape, behavior and assembly of solutes in solution. Hydrophobicity emerges from the collective behavior of large numbers of solvent molecules, so its accurate treatment is challenging. A decade ago, Lum, Chandler and Weeks (LCW) addressed this challenge indirectly by modeling how solvent density fluctuations couple to external solutes and constraints, and then inferring...

  13. Seasonal fluctuation of bacterial indicators in coastal waters

    OpenAIRE

    Maipa, Vasiliki; Alamanos, Yannis; Bezirtzoglou, Eugenia

    2011-01-01

    The relationships between number of coliforms, fecal coliforms, E. coli, fecal streptococci, location, time and seasonal factors in marine environments of northwest Greece were investigated over a period of 4 years. Research focused on measuring and comparing bacteria in coastal marine waters undergoing heavy bacterial charge during the tourist season. Microbiological pollution was increased during the summer period. Seasonal fluctuation of the fecal indicator bacteria was noted and concerned...

  14. Water level instrumentation simulation

    International Nuclear Information System (INIS)

    Through simulation, evaluations of system performance can be made to increase efficiency, reduce costs, enhance safety and provide effective training. A full function simulation for evaluating water level measurement requires modeling the physical process, the process instrumentation response and where appropriate, the human input/response. This paper examines a full function application simulating the primary system water level in a Boiling Water Reactor (BWR). The physical processes associated with BWR vessel level response are modeled with the Modular Accident Analysis Program (MAAP). The MAAP code is used as the basis for providing primary system and containment thermal-hydraulic response to a compendium of expected plant transients. The BWR vessel level instruments is modeled with the FAI developed Instrumentation PACkage (IPAC). With the thermal-hydraulic input from MAAP, the IPAC software models the various phenomena associated with water level measurements including the effects due to: (1) instrument channel calibration, (2) instrument drift and (3) containment (drywell) environmental effects. This paper discusses the IPAC models (instrumentation components) along with the factors which influence the mass balance of water in the downcomer region. A comparison of the BWR vessel water level complete simulation package to data from a simulated BWR plant transient culminates the discussion of this paper. The full function simulation package presented in this paper, enables a software-based representation of the BWR vessel level to be evaluated under various hypothetical plant conditions including normal, accident, and severe accident events. (author)

  15. Water Level Station History

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Images contain station history information for 175 stations in the National Water Level Observation Network (NWLON). The NWLON is a network of long-term,...

  16. River and groundwater level fluctuation analysis after barrage construction in riverside, South Korea

    Science.gov (United States)

    Baek, Keon Ha; Kim, Tae Hyung; Shin, Kyung Hee; Seom Bae, Jong

    2016-04-01

    Changes in river have brought to the change of groundwater hydrogeology and water quality. Also, the understanding of the interaction of groundwater and surface water is essential for the managing of effective water resource. In case of South Korea, there is increasing the interest of groundwater development and management in riverside through large river maintenance projects lately. The river water level was elevated than in the past and it is expected to the changes in the interaction between the existing groundwater and surface. This study analyzed the relationship between surrounding river water level and groundwater level in the 91 locations of groundwater observation wells, also was supposed to classify the similar pattern of groundwater by performing multivariate analysis. At the result of factor analysis, it is shown that the high and low factor in correlation between river water level and groundwater level were caused by receiving the significant external influence. In the result of cluster analysis, the middle and upper area of river were similar to the fluctuation pattern with river water level and groundwater level and the downstream area of river was shown with a low correlation. This is due to the characteristic showing a distribution of the alluvium in various types at the downstream area in compared to middle and upper area. In the future, the research is undergoing to analyze the time series of a point in time to account for the external influences of the effects on the groundwater level.

  17. Fluctuation patterns of groundwater levels in Tokyo caused by the Great East Japan Earthquake

    Science.gov (United States)

    Kawamura, Akira; Ishihara, Shigeyuki; Amaguchi, Hideo; Takasaki, Tadakatsu

    2016-04-01

    . Abrupt rising patterns in unconfined groundwater level were identified as an independent cluster. For the confined groundwater levels, drawdown just after the earthquake occurred about 90% of the wells, which is caused by the pressure release derived from crustal expansion. The most common fluctuation pattern after the drawdown is an increasing tendency of groundwater level, which is mainly caused by decreasing groundwater pumping rate due to the blackout. Groundwater level rising just after the earthquake especially for unconfined groundwater was caused by the phenomenon of liquefaction. In addition, the spatial characteristics and the causes of these patterns were also investigated. It is very important to understand this fluctuation correctly, not only for developing countermeasures for land subsidence and liquefaction, but also for water resource management. ,

  18. Computer simulation study of water using a fluctuating charge model

    Indian Academy of Sciences (India)

    M Krishnan; A Verma; S Balasubramanian

    2001-10-01

    Hydrogen bonding in small water clusters is studied through computer simulation methods using a sophisticated, empirical model of interaction developed by Rick et al (S W Rick, S J Stuart and B J Berne 1994 J. Chem. Phys. 101 6141) and others. The model allows for the charges on the interacting sites to fluctuate as a function of time, depending on their local environment. The charge flow is driven by the difference in the electronegativity of the atoms within the water molecule, thus effectively mimicking the effects of polarization of the charge density. The potential model is thus transferable across all phases of water. Using this model, we have obtained the minimum energy structures of water clusters up to a size of ten. The cluster structures agree well with experimental data. In addition, we are able to distinctly identify the hydrogens that form hydrogen bonds based on their charges alone, a feature that is not possible in simulations using fixed charge models. We have also studied the structure of liquid water at ambient conditions using this fluctuating charge model.

  19. Sea Levels Online: Sea Level Variations of the United States Derived from National Water Level Observation Network Stations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water level records are a combination of the fluctuations of the ocean and the vertical land motion at the location of the station. Monthly mean sea level (MSL)...

  20. Climate or vegetation change - what drove Holocene lake level fluctuations in NE-Germany?

    Science.gov (United States)

    Theuerkauf, Martin; Blume, Theresa; Dreibrodt, Janek; Heidbüchel, Ingo

    2016-04-01

    calculations will nevertheless provide a first test of our hypothesis on the importance of vegetation dynamics as a control on ground- and lake water level fluctuations. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution (ICLEA; www.iclea.de) of the Helmholtz Association (Grant Number VH-VI-415) and is supported by Helmholtz infrastructure of the Terrestrial Environmental Observatory (TERENO) North-eastern Germany.

  1. 三峡库区消落带沉积物重金属形态分布特征%Chemical fraction composition characteristics of heavy metals in sediments of water-level-fluctuating zone of Three Gorges Reservoir area

    Institute of Scientific and Technical Information of China (English)

    王图锦; 杨清伟; 潘瑾; 刘雪莲

    2012-01-01

    Objective To investigate the spatial distribution characteristics and chemical fraction composition characteristics of Cu, Pb, Cd and Cr in sediments of water-level-fluctuating zone of Three Gorges Reservoir area. Methods The sediment samples were collected at eleven typical sites in August, 2008. The concentrations and fraction composition characteristics of Cu, Pb, Cd and Cr were determined, and the environment quality evaluation of the sediment was carried out by the methods of geoaccumulation index and risk assessment code. Results The average contents of Cu, Pb, Cd and Cr in sediments were 84.0, S6.2, 0.S6 and 99.2 mg/kg respectively. The geoaccumulation index (Igro) analysis suggested "moderate pollution" of Cu and Cd, and "unpolluted to moderate pollution" of Pb and Cr. Fractionation studies indicated that Cd was predominantly associated with carbonate and Fe-Mn oxide fractions. Cd exhibited the greatest mobility and bioavailability, indicative of anthropogenic sources, while Cr was mainly found in the residual fraction, the average content of residual fraction of Cr reached 93.1%, and could be used as an indicator for the contribution from natural sources. Cu was predominantly associated with organic and residual fractions, and Pb with carbonate, Fe-Mn oxide and residual fractions. Risk assessment code(RAC) analysis indicated that Cd posed a high ecological risk to local environment, Cu was at low to medium risk level,Pb was at low to medium risk level,and Cr showed no to low risk level in sediments. The ecological risk ranked as Cd>Pb>Cu>Cr. Conclusion The pollution level of Cd in sediments from the investigated area is higher and the speciation of Cd exhibits high bioavailability and consequently this element posed a high ecological risk.%目的 了解三峡库区消落带沉积物中Cu、Pb、Cd、Cr四种重金属的形态含量及其分布特征.方法 于2008年8月汛期采集三峡库区消落带11个采样点的沉积物,测定Cu、Pb、Cd、Cr的

  2. A Mathematical View of Water Table Fluctuations in a Shallow Aquifer in Brazil.

    Science.gov (United States)

    Neto, Dagmar C; Chang, Hung K; van Genuchten, Martinus Th

    2016-01-01

    Detailed monitoring of the groundwater table can provide important data about both short- and long-term aquifer processes, including information useful for estimating recharge and facilitating groundwater modeling and remediation efforts. In this paper, we presents results of 4 years (2002 to 2005) of monitoring groundwater water levels in the Rio Claro Aquifer using observation wells drilled at the Rio Claro campus of São Paulo State University in Brazil. The data were used to follow natural periodic fluctuations in the water table, specifically those resulting from earth tides and seasonal recharge cycles. Statistical analyses included methods of time-series analysis using Fourier analysis, cross-correlation, and R/S analysis. Relationships could be established between rainfall and well recovery, as well as the persistence and degree of autocorrelation of the water table variations. We further used numerical solutions of the Richards equation to obtain estimates of the recharge rate and seasonable groundwater fluctuations. Seasonable soil moisture transit times through the vadose zone obtained with the numerical solution were very close to those obtained with the cross-correlation analysis. We also employed a little-used deep drainage boundary condition to obtain estimates of seasonable water table fluctuations, which were found to be consistent with observed transient groundwater levels during the period of study.

  3. Carbon and strontium isotope variations and responses tosea-level fluctuations in the Ordovician of the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Abstract In the Ordovician, a carbonate platform system grading from the platformal interioreastwards to basin was developed in the Tazhong area of the Tarim Basin, and the study column islocated in the place where the paleoslope occurred. The isotope compositions of the carbonatesthere are thus considered as having reflected those of simultaneous sea waters in view of its goodconnection with the open seas. The carbon and strontium isotope compositions of the Ordoviciancarbonates in the Tazhong area are analyzed, and their relationships to the sea-level fluctuationsare discussed as well. Studies have revealed that the carbon isotope composition is related posi-tively with the sea-level fluctuations, whereas an opposing situation occurs to the strontium isotopevariation. Similar responses of carbon and strontium isotope compositions to the sea-level fluctua-tions are reported elsewhere in the world, suggesting that the Ordovician sea-level fluctuations ofthe Tarim Basin were of eustatic implication.

  4. Hall Voltage Fluctuations as a Diagnostic of Internal Magnetic Field Fluctuations in High Temperature Superconductors and the Half-filled Landau Level

    OpenAIRE

    Ioffe, L. B.; Lesovik, G. B.; Millis, A.J.

    1996-01-01

    Fluctuations of the Hall voltage reveal information about long wavelength magnetic field fluctuations. If gauge theories of strongly correlated electrons are correct, such fluctuations are particularly large in the half-filled Landau level and in high $T_c$ superconductors. We present estimates for the magnitude, system size and frequency dependence of these fluctuations. The frequency dependence contains information about instantons in the gauge field.

  5. Water levels shape fishing participation in flood-control reservoirs

    Science.gov (United States)

    Miranda, Leandro E.; Meals, K. O.

    2013-01-01

    We examined the relationship between fishing effort (hours fished) and average March–May water level in 3 flood control reservoirs in Mississippi. Fishing effort increased as water level rose, peaked at intermediate water levels, and decreased at high water levels. We suggest that the observed arched-shaped relationship is driven by the shifting influence of fishability (adequacy of the fishing circumstances from an angler's perspective) and catch rate along a water level continuum. Fishability reduces fishing effort during low water, despite the potential for higher catch rates. Conversely, reduced catch rates and fishability at high water also curtail effort. Thus, both high and low water levels seem to discourage fishing effort, whereas anglers seem to favor intermediate water levels. Our results have implications for water level management in reservoirs with large water level fluctuations.

  6. Communication Networks - Analysis of jitter due to call-level fluctuations

    NARCIS (Netherlands)

    M.R.H. Mandjes

    2007-01-01

    Abstract In communication networks used by constant bit rate applications, call-level dynamics (i.e. entering and leaving calls) lead to fluctuations in the load, and therefore also fluctuations in the delay (jitter). By intentionally delaying the packets at the destination, one can transform the pe

  7. A delineation of regional hydraulic conductivity based on water table fluctuation

    Science.gov (United States)

    Park, Eungyu; Kim, Kue-Young; Ding, Guoping; Kim, Kangjoo; Han, Weon Shik; Kim, Yeongkyoo; Kim, Namjin

    2011-03-01

    SummaryThe estimation of regional hydraulic conductivity is essential for the sustainable development and efficient management of groundwater. This paper presents a new physical method of estimating hydraulic conductivity based on the water level fluctuation model developed by Park and Parker (Park, E., Parker, J.C., 2008. A simple model for water table fluctuations in response to precipitation. J. Hydrol. 356, 344-349). The developed procedure was validated by comparison with the hypothetical numerical model for a variety of hydraulic conductivities, aquifer inclinations, and the heterogeneities. The model was found to be highly reliable when using water level data far from the hydraulic boundaries. The results show that the monitoring data obtained over a range of relative distances of an observation location ( x) to the flow domain ( W), x/ W > 0.2 avoided the boundary effects. A correction factor was also proposed based on the deviation analysis of the calibrated K and f/ n (ratio of recharge to precipitation divided by porosity). The results from the basal inclinations and the heterogeneities cases suggest that the estimated hydraulic conductivity is representing regional property rather than the local one. To confirm the validity of the proposed procedure, it was applied to the coastal aquifer of Jeju Island, Korea. The calibrated hydraulic conductivities were consistent with the results from previous studies. These results show that the proposed method is an effective and economical means to estimate hydraulic conductivity of large supporting volumes of subsurface aquifers with the convenient use of recharge and groundwater level data.

  8. RESPONSE OF TYPICAL HYDRODYNAMIC PRESSURE LANDSLIDE TO RESERVOIR WATER LEVEL FLUCTUATION:SHUPING LANDSLIDE IN THREE GORGES RESERVOIR AS AN EXAMPLE%动水压力型滑坡对库水位升降作用的响应--以三峡库区树坪滑坡为例

    Institute of Scientific and Technical Information of China (English)

    向玲; 王世梅; 王力

    2014-01-01

    Numerous wading landslides formed in Three Gorges Reservoir.Water level cyclical fluctuations causes the changes of properties of the rock-soil bank landslides,also make the changes of seepage field and the stability of the landslides.This paper studies the response of the wading landslide's stability induced by water level fluctuation. It analyses the hydrodynamic pressure landslide using the classification of significant wading landslide in Three Gorges Reservoir.It takes the Zigui Shuping Landslide as a case study.The SEEP and SLOPE modules Geo-studio software are used to model the process of seepage field and calculate the stability,analyzes the law of effect hydrodynamic pressure landslide under different permeability coefficients of the landslide and the water level rate. The results show that the groundwater level has a concave phenomenon and the stability coefficient increases when the reservoir water level rises.The groundwater level has a convex phenomenon and the stability coefficient obvious decreases when the reservoir water level reduces for hydrodynamic pressure landslide.The reservoir water level fluctuation has the larger rate,and the permeability coefficient is smaller.The reservoir water level fluctuation has more obvious effect on the seepage and stability of the landslide.%三峡库区涉水型滑坡众多,库水位周期性涨落引起库岸滑坡岩土体物理性质的改变,还使得滑体内渗流场发生变化,进而影响滑坡体稳定性。为研究库水位升降作用对涉水边坡稳定性的影响,基于三峡库区重大涉水滑坡分类,对动水压力型滑坡进行分析。以三峡库区秭归县树坪滑坡为例,利用Geo-Studio软件的SEEP模块及SLOPE分别对滑坡渗流场与稳定性进行计算,分析不同滑体渗透系数及不同库水位升降速率对动水压力型滑坡的影响规律。结果表明:对于动水压力型滑坡,库水位上升过程中,地下水位线有下凹趋势,

  9. Fluctuations in sedation levels may contribute to delirium in ICU patients

    DEFF Research Database (Denmark)

    Svenningsen, Helle; Egerod, I; Videbech, Poul;

    2013-01-01

    Delirium in patients admitted to the intensive care unit (ICU) is a serious complication potentially increasing morbidity and mortality. The aim of this study was to investigate the impact of fluctuating sedation levels on the incidence of delirium in ICU.......Delirium in patients admitted to the intensive care unit (ICU) is a serious complication potentially increasing morbidity and mortality. The aim of this study was to investigate the impact of fluctuating sedation levels on the incidence of delirium in ICU....

  10. Mechanism of temperature fluctuation phenomena below steam-water interface in a pressurizer spray pipe

    International Nuclear Information System (INIS)

    In a PWR plant, a steam-water two-phase flow may exist in the pressurizer spray pipe under a normal operating condition since the flow rate of the spray water is not sufficient to fill the horizontal section of the pipe completely. Initiation of high cycle fatigue cracks is suspected to occur under such thermally stratified two phase flow conditions. Experiments for a steam-water flow have been conducted to investigate the temperature fluctuation phenomena. It has been shown that the wall temperature fluctuations were not caused by the waves on the water surface, but were caused by temperature fluctuations in water layer below the interface. An experiment with visualization test section of rectangular pipe was conducted to investigate the temperature fluctuation mechanism in water layer in this paper. The black stripe pattern was observed below the steam-water interface due to the density change. The water temperature fluctuations had the dominant frequency of about 1Hz. The Richardson number calculated with the measured temperature and velocity gradient was larger than 0.25. The dominant frequency of temperature fluctuations was nearly equal to the Brunt-Väisälä frequency. It was shown that the temperature fluctuations in water layer below the interface were caused by the internal gravity wave in the thermal stratified flow. (author)

  11. Biodegradation of Toluene Under Seasonal and Diurnal Fluctuations of Soil-Water Temperature.

    KAUST Repository

    Yadav, Brijesh K

    2012-05-12

    An increasing interest in bioremediation of hydrocarbon polluted sites raises the question of the influence of seasonal and diurnal changes on soil-water temperature on biodegradation of BTEX, a widespread group of (sub)-surface contaminants. Therefore, we investigated the impact of a wide range of varying soil-water temperature on biodegradation of toluene under aerobic conditions. To see the seasonal impact of temperature, three sets of batch experiments were conducted at three different constant temperatures: 10°C, 21°C, and 30°C. These conditions were considered to represent (1) winter, (2) spring and/or autumn, and (3) summer seasons, respectively, at many polluted sites. Three additional sets of batch experiments were performed under fluctuating soil-water temperature cases (21<>10°C, 30<>21°C, and 10<>30°C) to mimic the day-night temperature patterns expected during the year. The batches were put at two different temperatures alternatively to represent the day (high-temperature) and night (low-temperature) times. The results of constant- and fluctuating-temperature experiments show that toluene degradation is strongly dependent on soil-water temperature level. An almost two-fold increase in toluene degradation time was observed for every 10°C decrease in temperature for constant-temperature cases. Under fluctuating-temperature conditions, toluene degraders were able to overcome the temperature stress and continued thriving during all considered weather scenarios. However, a slightly longer time was taken compared to the corresponding time at daily mean temperature conditions. The findings of this study are directly useful for bioremediation of hydrocarbon-polluted sites having significant diurnal and seasonal variations of soil-water temperature.

  12. Cluster regression model and level fluctuation features of Van Lake, Turkey

    Directory of Open Access Journals (Sweden)

    Z. Şen

    Full Text Available Lake water levels change under the influences of natural and/or anthropogenic environmental conditions. Among these influences are the climate change, greenhouse effects and ozone layer depletions which are reflected in the hydrological cycle features over the lake drainage basins. Lake levels are among the most significant hydrological variables that are influenced by different atmospheric and environmental conditions. Consequently, lake level time series in many parts of the world include nonstationarity components such as shifts in the mean value, apparent or hidden periodicities. On the other hand, many lake level modeling techniques have a stationarity assumption. The main purpose of this work is to develop a cluster regression model for dealing with nonstationarity especially in the form of shifting means. The basis of this model is the combination of transition probability and classical regression technique. Both parts of the model are applied to monthly level fluctuations of Lake Van in eastern Turkey. It is observed that the cluster regression procedure does preserve the statistical properties and the transitional probabilities that are indistinguishable from the original data.

    Key words. Hydrology (hydrologic budget; stochastic processes · Meteorology and atmospheric dynamics (ocean-atmosphere interactions

  13. Water Density Fluctuations Relevant to Hydrophobic Hydration are Unaltered by Attractions

    CERN Document Server

    Remsing, Richard C

    2014-01-01

    An understanding of density fluctuations in bulk water has made significant contributions to our understanding of the hydration and interactions of idealized, purely repulsive hydrophobic solutes. To similarly inform the hydration of realistic hydrophobic solutes that have dispersive interactions with water, here we characterize water density fluctuations in the presence of attractive fields that correspond to solute-water attractions. We find that when the attractive field acts only in the solute hydration shell, but not in the solute core, it does not significantly alter water density fluctuations in the solute core region. We further find that for a wide range of solute sizes and attraction strengths, the free energetics of turning on the attractive fields in bulk water are accurately captured by linear response theory. Our results also suggest strategies for more efficiently estimating hydration free energies of realistic solutes in bulk water and at interfaces.

  14. Water Level Sensors, What Works?

    OpenAIRE

    Heiner, Bryan J.; Gill, Thomas W.

    2012-01-01

    ABSTRACT: Water level sensors come in all shapes, sizes, and types and can range in price from a couple hundred to several thousand US dollars. This project utilizes real world examples from around the western United States to determine what level sensors work well and to document what characteristics may prevent them from providing accurate water level measurements in differing climates. Researchers have developed a calibration procedure that can be used in field or laboratory situations to ...

  15. 500,000 years of water table fluctuations recorded in Devils Hole 2 cave from southwestern Nevada, USA

    Science.gov (United States)

    Wendt, Kathleen A.; Moseley, Gina E.; Dublyansky, Yuri V.; Spötl, Christoph; Edwards, R. Lawrence

    2016-04-01

    Evidence for large reoccurring Pleistocene lakes in the Great Basin region of North America suggests that this modern day arid landscape underwent drastic climate fluctuations in the past. We aim to reconstruct the history of water table fluctuations in the discharge area of the Ash Meadow groundwater flow system since 500 ka BP. To do so, we have analyzed a series of carbonate cores drilled at varying elevations above the modern day water table from the walls of Devils Hole 2 cave in southwest Nevada, USA. Petrographic and morphologic differences between calcite precipitated below (mammillary calcite) or at (folia) the water table in this cave record past variations in water table elevation. A total of ten cores were drilled between 0.8 and 15.1 m above the modern day water table. Each core includes alternations between mammillary calcite to folia, with an increasing occurrence of folia in higher elevation cores, suggesting multi-meter variations in past water table elevation. Over 50 high-precision 230Th dates have been measured at the mammillary calcite to folia boundaries of each core. Preliminary results show multi-meter water table fluctuations which appear to follow interglacial-glacial cycles from 500 ka to present day, such that water table high-stands coincide with glacial periods. Observed maxima in water table levels are likely correlated to periods of increased precipitation within the catchment area during glacial (pluvial) periods, which is consistent with paleoclimate records in this region. Preliminary results suggest water table levels peaked (reaching +5.5 m or higher than present day water table) at 461 kyr, between 320 and 250 kyr, between 196 and 137 kyr, and between 67 and 20 kyr BP, largely coinciding with glacial periods. Periods in which water table levels reached the lowest elevation sampled (+0.8 m) occurred at 240 kyr, 116 kyr, and 5.7 kyr BP, largely coinciding with interglacial periods.

  16. 水位变动及降雨入渗联合作用对岩溶地面塌陷的影响分析%Analysis of Joint Action of Water Level Fluctuation and Rainfall on the Influence of Karst Ground Collapse

    Institute of Scientific and Technical Information of China (English)

    周建; 张映钱; 方亿刚; 刘宇

    2016-01-01

    为了预测地区岩溶塌陷的模式及可能性 ,以武汉市陆家街岩溶地面塌陷为研究对象 ,选择多年长江武汉关枯水期和丰水期的平均水位 ,借鉴库伦土压力理论 ,建立类黏性土承压变负压的圆坛型岩溶塌陷预测模型 ,计算其在水位下降与降雨联合作用下的抗塌系数进行初步评价 ,并进一步采用GeoStudio软件的SEEP/W和SIGMA/W模块建立降雨、地下水水位升降-应力应变数值耦合分析模型 ,研究在不同降雨强度和持续时间下土洞的发展过程.结果表明降雨时间越长 ,降雨强度越强 ,土洞位移越大 ;在长江补给联合降雨作用下的位移较大 ,通过不同时间位移和应力分布可以得到其致塌模式为潜蚀 -渗压-重力型 ,成因机制主要为降雨及长江水位变化引起的潜蚀渗压作用.%To analysis the joint action of water level fluctuation and rainfall on the influence of karst ground collapse ,this paper took Lujia street karst ground collapse in Wuhan city as an example ,and proposed a model for the region of karst ground collapse pressure under negative pressure .It also calculated the decline of water level and rainfall under the joint action of collapse resistance coefficient by using GeoStudio software SEEP/W and SIGMA/W module .Different rainfall , water level fluctuation were considered .It chose the mutagenicity and plentiful average water level of Yangtze river water level (Wuhan) ,the results showed that the longer the greater rainfall intensity ,the greater the displacement of the soil holes ,and joint under the action of rainfall in the Yangtze river supplies displacement is larger ,the reason could be that as the increased permeability of rock mass lowered the mechanical property ,displacement and stress distribution in differ-ent time can change it from underground erosion to osmotic pressure and gravity type ,therefore the main reason should be the rainfall and the Yangtze river water level

  17. THE EFFECTS OF WATER TEMPERATURE REGIME FLUCTUATIONS ON THE EMBRYONIC DEVELOPMENT OF SILVER CARP (HYPOPHTHALMICHTHYS MOLITRIX

    Directory of Open Access Journals (Sweden)

    А. Vodyanitskyi

    2015-03-01

    Full Text Available Purpose. To determine the effect of temperature regime fluctuations on the development of silver carp embryos, as well as the activity of enzymatic reactions in fish eggs. Methodology. The studies were conducted at the experimental station of the Institute of Hydrobiology of Bila Tserkov, Ukrainian National Academy of Sciences, from June to July. The biological materials were silver carp eggs, embryos and larvae. The dissolved oxygen content was determined using the Winkler method at four o’clock in the morning. Alkalinity phosphatase and LDG activity were determined using a set of reagents «Alkalinity phosphatase» and «LDG» (Phyllis diagnosis, Ukraine. SDH activity was determined by Vexy. The activity of Na, K-Mg-dependent-activated ATPase was determined as growth of inorganic phosphorus in the incubation medium by Kindratova M.N. et al. Protease activity was determined using immune enzymatic method of Tyurina et al. The obtained results were processed statistically in Statistica 5.5, Epaprobit analysis was used for calculating LC/EC values (Version 1.5. Findings The results showed that a delay of embryonic stages of development occur, the number of abnormal embryos increases, and the reproduction efficiency of fish reduces with an increase in water temperature and decrease in the dissolved oxygen content in water. The temperature factor had a significant effect on the activity of key enzymes, in particular the energetic metabolism changed from aerobic to anaerobic. Originality. It was found a negative effect of abiotic factors of water medium and drastic fluctuations in water temperature and gas regime of water bodies on the course of embryogenesis of silver carp that is especially important in the conditions of climate change. Practical value. The obtained results showed that the level of optimum and unfavorable environmental factors during the change of embryonic stages in embryonic and larval fish can be established based on the

  18. Calculation and analysis of thermal–hydraulics fluctuations in pressurized water reactors

    International Nuclear Information System (INIS)

    Highlights: • Single-phase thermal–hydraulics noise equations are originally derived in the frequency domain. • The fluctuations of all the coolant parameters are calculated, without any simplifying assumptions. • The radial distribution of the temperature fluctuations in the fuel, gap and cladding are taken into account. • The closed-loop calculations are performed by means of the point kinetics noise theory. • Both the space- and frequency-dependence of the thermal–hydraulics fluctuations are analyzed. - Abstract: Analysis of thermal–hydraulics fluctuations in pressurized water reactors (e.g., local and global temperature or density fluctuations, as well as primary and charging pumps fluctuations) has various applications in calculation or measurement of the core dynamical parameters (temperature or density reactivity coefficients) in addition to thermal–hydraulics surveillance and diagnostics. In this paper, the thermal–hydraulics fluctuations in PWRs are investigated. At first, the single-phase thermal–hydraulics noise equations (in the frequency domain) are originally derived, without any simplifying assumptions. The fluctuations of all the coolant parameters, as well as the radial distribution of the temperature fluctuations in the fuel, gap and cladding are taken into account. Then, the derived governing equations are discretized using the finite volume method (FVM). Based on the discretized equations and the proposed algorithm of solving, a single heated channel noise calculation code (SHC-Noise) is developed, by which the steady-state and fluctuating parameters of PWR fuel assemblies can be calculated. The noise sources include the inlet coolant temperature and velocity fluctuations, in addition to the power density noises. The developed SHC-Noise code is benchmarked in different cases and scenarios. Furthermore, to show the effects of the power feedbacks, the closed-loop calculations are performed by means of the point kinetics noise

  19. Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations

    Science.gov (United States)

    Zhou, Shenggao; Sun, Hui; Cheng, Li-Tien; Dzubiella, Joachim; Li, Bo; McCammon, J. Andrew

    2016-08-01

    Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the "normal velocity" that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the inclusion of

  20. Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations.

    Science.gov (United States)

    Zhou, Shenggao; Sun, Hui; Cheng, Li-Tien; Dzubiella, Joachim; Li, Bo; McCammon, J Andrew

    2016-08-01

    Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the "normal velocity" that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the inclusion of

  1. Stochastic level-set variational implicit-solvent approach to solute-solvent interfacial fluctuations.

    Science.gov (United States)

    Zhou, Shenggao; Sun, Hui; Cheng, Li-Tien; Dzubiella, Joachim; Li, Bo; McCammon, J Andrew

    2016-08-01

    Recent years have seen the initial success of a variational implicit-solvent model (VISM), implemented with a robust level-set method, in capturing efficiently different hydration states and providing quantitatively good estimation of solvation free energies of biomolecules. The level-set minimization of the VISM solvation free-energy functional of all possible solute-solvent interfaces or dielectric boundaries predicts an equilibrium biomolecular conformation that is often close to an initial guess. In this work, we develop a theory in the form of Langevin geometrical flow to incorporate solute-solvent interfacial fluctuations into the VISM. Such fluctuations are crucial to biomolecular conformational changes and binding process. We also develop a stochastic level-set method to numerically implement such a theory. We describe the interfacial fluctuation through the "normal velocity" that is the solute-solvent interfacial force, derive the corresponding stochastic level-set equation in the sense of Stratonovich so that the surface representation is independent of the choice of implicit function, and develop numerical techniques for solving such an equation and processing the numerical data. We apply our computational method to study the dewetting transition in the system of two hydrophobic plates and a hydrophobic cavity of a synthetic host molecule cucurbit[7]uril. Numerical simulations demonstrate that our approach can describe an underlying system jumping out of a local minimum of the free-energy functional and can capture dewetting transitions of hydrophobic systems. In the case of two hydrophobic plates, we find that the wavelength of interfacial fluctuations has a strong influence to the dewetting transition. In addition, we find that the estimated energy barrier of the dewetting transition scales quadratically with the inter-plate distance, agreeing well with existing studies of molecular dynamics simulations. Our work is a first step toward the inclusion of

  2. CO2 phase mutation by fluctuating water table in the vadose zone over a CCS site

    Science.gov (United States)

    Joun, W.; Ha, S. W.; Kim, H. H.; Kim, T. W.; Lee, S. S.; Lee, K. K.

    2015-12-01

    Geological sequestration of carbon dioxide (CO2) is one of the feasible plans to control greenhouse gas emissions. In order to be more perfect, the plan has to prove that the injected CO2 gas will not be leaking. Even if CO2 leaking happens, we should possess a technique which provides information on specific aquifer system before critical effect to ground and subsurface environments. Many parameters have been utilized for early detection before risk to environments by sensing CO2 gas concentration, electric conductivity, pH, and ion analysis. However, these are not enough to all CCS sites for leakage detection. For example, the importance of gas leaking path is emphasized because finding the dominant gas flow path can reduce risk and provide a quick estimation. Herein, we investigate dissolved solute degassing and vertical flow from saturated zone to unsaturated zone in shallow depth aquifer. Especially we focused on the water table fluctuation effect. Based on field data and basic parameters, we perform a pilot scale gas injection test and calculate gas flow saturation with STOMP simulator. The CO2 gas concentrations at different depth levels according to amount of injected CO2 infused water, CO2 gas saturation in vadose zone have different concentration values. If we estimate this phenomenon in vadose zone by using CO2 gas detection method, we could presume that the CO2 dissolved in shallow groundwater is degassing and flow upward into vadose zone. However, the concentration level and change patterns are not same and will be changed according to the pattern of water table fluctuation. This study could be usefully applied to strategic CCS environmental monitoring of CO2 leakage.Acknowledgement: Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003).

  3. Periodic fluctuations in deep water formation due to sea ice

    CERN Document Server

    Saha, Raj

    2015-01-01

    During the last ice age several quasi-periodic abrupt warming events took place. Known as Dansgaard-Oeschger (DO) events their effects were felt globally, although the North Atlantic experienced the largest temperature anomalies. Paleoclimate data shows that the fluctuations often occurred right after massive glacial meltwater releases in the North Atlantic and in bursts of three or four with progressively decreasing strengths. In this study a simple dynamical model of an overturning circulation and sea ice is developed with the goal of understanding the fundamental mechanisms that could have caused the DO events. Interaction between sea ice and the overturning circulation in the model produces self-sustained oscillations. Analysis and numerical experiments reveal that the insulating effect of sea ice causes the ocean to periodically vent out accumulated heat in the deep ocean into the atmosphere. Subjecting the model to idealized freshwater forcing mimicking Heinrich events causes modulation of the natural p...

  4. Investigation of temperature fluctuation phenomena in pressurizer spray pipe of pressurized water reactor

    International Nuclear Information System (INIS)

    Gas liquid interface is formed in a pressurizer spray pipe of a pressurized water reactor when flow rate is small at normal reactor operation. Temperature fluctuation may occur if the interface moves periodically. Measurement of inner wall and fluid temperature in the test section simulating the real pressurizer spray pipe was conducted to study mechanism of the temperature fluctuation phenomena. The effect of non-condensable gas was investigated by injecting helium gas into test section. When helium gas was injected, the condensation of the vapor was suppressed and the temperature fluctuation was reduced. Richardson number increases with the helium gas injection, which is higher than 0.25 in all conditions of the present experiment. Brunt Vaisala frequency nearly equal to the peak of temperature power spectral density. It seemed that the internal gravity waves caused temperature fluctuations in water layer below the interface. (author)

  5. Effect of Soil and Dominant Plants on Mercury Speciation in Soil and Water System of Water-Level-Fluctuation Zone in the Three Gorges Area%三峡水库消落带土壤与优势植物淹水后对土-水系统汞形态的影响

    Institute of Scientific and Technical Information of China (English)

    梁丽; 王永敏; 张成; 余亚伟; 安思危; 王定勇

    2016-01-01

    Plentiful plants in the water-level-fluctuation-zone (WLFZ) of Three Gorges Reservoir (TGR) grow vigorously during the non-flooded period, especially the herbaceous ones. Then, the WLFZ is submerged gradually from the end of September. Soil-plant system that under a long time flooded condition may change the form of mercury, thus resulting in a secondary pollution of the water environment in TGR. To understand the characteristics of mercury species in soils and water after submerged, four kinds of typical plants from TGR were tested in the lab under submerged condition. The results indicated that the plants could promote the formation of soil methylmercury (MeHg), and had a significant effect on the different forms of mercury concentrations of the overlying water during inundation. Cynodon dactylon as the dominant species in WLFZ, because of its higher content of total mercury ( THg) and methylmercury, the effect on MeHg and the other forms of mercury in the soil and the overlying water system was obvious. After 90 days, the soil MeHg level was the highest in Cynodon dactylon ﹠ soil ﹠ water treatment (B1)[(1 135. 86 ± 113. 84) ng•kg - 1 ]. It was approximately 2 times less than that of the soil MeHg in soil ﹠ water treatment (CK2). The variation characteristics of total mercury (THg), reactive mercury (RHg), dissolved mercury (DHg), total methylmercury (TMeHg) and dissolved methylmercury (DMeHg) of overlying water all showed a parabolic shape with a peak skewed to the left, and the peak was reached on the 30th day. Meanwhile, TMeHg, THg and DHg in B1 treatment were the highest, which were (2. 88 ± 0. 06),(40. 29 ± 2. 42) and (35. 51 ± 3. 77) ng•L - 1 respectively, and TMeHg and THg in the overlying water were mainly in the form of dissolved state. Therefore, it could be inferred that the water consumption of the Three Gorges reservoir would increase the mercury pollution load of the reservoir.%三峡库区消落带落干期植被生长茂盛,蓄水

  6. Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow

    DEFF Research Database (Denmark)

    Massman, W.J.; Ibrom, Andreas

    2008-01-01

    of EC-related tube attenuation effects have either not considered this issue at all or have only examined it superficially. Nonetheless, the attenuation of water vapor fluctuations is clearly much greater than might be expected from a passive tracer in turbulent tube flow. This study reexamines...... the turbulent tube flow issue for both passive and sorbing tracers with the intent of developing a physically-based semi-empirical model that describes the attenuation associated with water vapor fluctuations. Toward this end, we develop a new model of tube flow dynamics (radial profiles of the turbulent......Recent studies with closed-path eddy covariance (EC) systems have indicated that the attenuation of fluctuations of water vapor concentration is dependent upon ambient relative humidity, presumably due to sorption/desorption of water molecules at the interior surface of the tube. Previous studies...

  7. Statistical analysis of the fluctuating counts of fecal bacteria in the water of Lake Kinneret.

    Science.gov (United States)

    Hadas, Ora; Corradini, Maria G; Peleg, Micha

    2004-01-01

    Counts of E. coli, Enteroccoci and fecal coliforms in four sites around Lake Kinneret (The Sea of Galilee), collected every 2-4 weeks for about 5 years during 1995-2002 showed irregular fluctuations punctuated by aperiodic outbursts of variable magnitude. Because of the haphazard nature of fecal contamination and large intervals between successive counts, these patterns were described by probabilistic models, based on the truncated Laplace or Extreme Value distribution. Their applicability was tested by comparing the predicted frequencies of counts exceeding different levels calculated from the first half of each record with those actually observed in its second half. Despite the records imperfections and minor violations of the underlying models' assumptions, there was a reasonable agreement between the estimated and actual frequencies. This demonstrated that it is possible to translate the irregular fluctuation pattern into a set of probabilities of future high counts. In principle, such probabilities can be used to quantify the water's fecal contamination pattern and as a tool to assess the efficacy of preventive measures to reduce it.

  8. Estimating evapotranspiration and groundwater flow from water-table fluctuations for a general wetland scenario

    Science.gov (United States)

    Migration_USER, IPDS; Wiley, Michael J.; Wilcox, Douglas A.

    2016-01-01

    The use of diurnal water-table fluctuation methods to calculate evapotranspiration (ET) and groundwater flow is of increasing interest in ecohydrological studies. Most studies of this type, however, have been located in riparian wetlands of semi-arid regions where groundwater levels are consistently below topographic surface elevations and precipitation events are infrequent. Current methodologies preclude application to a wider variety of wetland systems. In this study, we extended a method for estimating sub-daily ET and groundwater flow rates from water-level fluctuations to fit highly dynamic, non-riparian wetland scenarios. Modifications included (1) varying the specific yield to account for periodic flooded conditions and (2) relating empirically derived ET to estimated potential ET for days when precipitation events masked the diurnal signal. To demonstrate the utility of this method, we estimated ET and groundwater fluxes over two growing seasons (2006–2007) in 15 wetlands within a ridge-and-swale wetland complex of the Laurentian Great Lakes under flooded and non-flooded conditions. Mean daily ET rates for the sites ranged from 4.0 mm d−1 to 6.6 mm d−1. Shallow groundwater discharge rates resulting from evaporative demand ranged from 2.5 mm d−1 to 4.3 mm d−1. This study helps to expand our understanding of the evapotranspirative demand of plants under various hydrologic and climate conditions. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  9. A Delineation of Regional Hydraulic Properties Based on Water Table Fluctuation

    Science.gov (United States)

    Park, E.; Han, W.

    2011-12-01

    The estimation of regional hydraulic conductivity is essential for the sustainable development and efficient management of groundwater. This paper presents a new physical method of estimating hydraulic conductivity and recharge to precipitation ratio based on the water level fluctuation model. The developed procedure was validated by comparison with the hypothetical numerical model for a variety of hydraulic conductivities, aquifer inclinations, and the heterogeneities. The model was found to be highly reliable when using water level data far from the hydraulic boundaries. The results show that the monitoring data obtained over a range of relative distances of an observation location (x) to the flow domain (W), x/W > 0.2 avoided the boundary effects. A correction factor was also proposed based on the deviation analysis of the calibrated K and f/n (ratio of recharge to precipitation divided by porosity). The results from the basal inclinations and the heterogeneities cases suggest that the estimated hydraulic conductivity is representing regional property rather than the local one. To confirm the validity of the proposed procedure, it was applied to the coastal aquifer of Jeju Island, Korea. The calibrated hydraulic conductivities and recharge to precipitation ratio were consistent with the results from previous studies. These results show that the proposed method is an effective and economical means to estimate hydraulic properties of large supporting volumes of subsurface aquifers with the convenient use of recharge and groundwater level data.

  10. The Fluctuating Political Appeal of Water Engineering in Australia

    Directory of Open Access Journals (Sweden)

    Lin R. Crase

    2009-10-01

    Full Text Available Like many nations, Australia has a mixed history with water engineering. For over a century the engineer was 'king' and water was harnessed as a vehicle for settling the harsh inland, creating wealth and building prosperity. By the 1960s it was becoming increasingly clear that this approach was not without its flaws. Mounting evidence of environmental degradation emerged in the 1970s and the trend towards fiscal responsibility in the 1980s subjected the engineering approach to even greater scrutiny. These events set the context for a series of water policy reforms that commenced in earnest in the early 1990s. Initially, the reforms favoured greater use of economic incentives and focussed attention on the ecological impacts of water management. In this environment, the status of the engineer was transformed from 'king' to 'servant'. However, the engineering profession was not to hold this status for long and the political difficulties of simultaneously dealing with the economics and ecology of water quickly became the rationale for reverting to engineering solutions. This paper traces these historical events and focusses specifically on the politically vexing issues that arise when water reallocation is attempted in a fully allocated basin.

  11. Mercury Dynamics of Several Plants Collected from the Water-Level Fluctuation Zone of the Three Gorges Reservoir Area During Flooding and Its Impact on Water Body%三峡库区消落带3种植物淹水后汞的动态变化及其对水体的影响

    Institute of Scientific and Technical Information of China (English)

    张翔; 张成; 孙荣国; 王定勇

    2014-01-01

    Submerged plants are a major source for the abnormal elevation of methylmercury in reservoir. Several specific plants (Echinochloa crusgalli, Cynodondactylon and Corn stoυer) were collected and inundated in a simulated aquatic environment in the laboratory for investigating the mercury (Hg) dynamics in plants and the release process into water, aiming to find out the properties of Hg dynamics of plants under inundation conditions and its impact on water body in the Water-Level Fluctuation Zone of the Three Gorges Reservoir Area. The results showed that the contents of total mercury in several plants were in the range of 9. 21-12. 07 ng·g - 1 , and the percentage content of methylmercury (MeHg) was about 1% -2% . The content of total mercury (THg) in plants gradually decreased, by 35. 81% -55. 96% , whereas that of the dissolved mercury (DHg) increased sharply, by 103. 23% -232. 15% , which indicated an emission of Hg from plants to water in the process of decomposition. Furthermore, the state of inundation provided sufficient conditions for the methylation process in plants and therefore caused an increase of the content of methylmercury in the plant residues, which was 3. 04-6. 63 times as much as the initial content. The concentration of dissolved methylmercury (DMeHg) in the overlying water also increased significantly by 14. 84- 16. 05 times compared with the initial concentration. Meanwhile, the concentration of dissolved oxygen (DO) in the overlying water was significantly and negatively correlated with DMeHg. On the other hand, the concentration of dissolved organic carbon ( DOC) in the overlying water was significantly and positively correlated with DMeHg. During the whole inundation period, the increase of DHg in the overlying water accounted for 41. 74% -47. 01% of the total amount of THg emission, and there was a negative correlation between the content of THg in plant residues and that of DHg in the overlying water.%被淹没的植物是水库甲基

  12. RAPID FLUCTUATIONS OF WATER MASER EMISSION IN VY CMa

    Institute of Scientific and Technical Information of China (English)

    ZhengXingwu; EugenioScaliseJr; HanFu

    1999-01-01

    The monitoring observations of the short- time variation of the water maser to-ward the supergiant star of VY CMa were carried out from August 26 through September 24 1993, using the 13.7 m telescope at the Qinghai station of the Purple

  13. Changes in climate, catchment vegetation and hydrogeology as the causes of dramatic lake-level fluctuations in the Kurtna Lake District, NE Estonia

    Directory of Open Access Journals (Sweden)

    Marko Vainu

    2014-02-01

    Full Text Available Numerous lakes in the world serve as sensitive indicators of climate change. Water levels for lakes Ahnejärv and Martiska, two vulnerable oligotrophic closed-basin lakes on sandy plains in northeastern Estonia, fell more than 3 m in 1946–1987 and rose up to 2 m by 2009. Earlier studies indicated that changes in rates of groundwater abstraction were primarily responsible for the changes, but scientifically sound explanations for water-level fluctuations were still lacking. Despite the inconsistent water-level dataset, we were able to assess the importance of changing climate, catchment vegetation and hydrogeology in water-level fluctuations in these lakes. Our results from water-balance simulations indicate that before the initiation of ground­water abstraction in 1972 a change in the vegetation composition on the catchments triggered the lake-level decrease. The water-level rise in 1990–2009 was caused, in addition to the reduction of groundwater abstraction rates, by increased precipitation and decreased evaporation. The results stress that climate, catchment vegetation and hydrogeology must all be considered while evaluating the causes of modern water-level changes in lakes.

  14. The effects of climatic fluctuations and extreme events on running water ecosystems.

    Science.gov (United States)

    Woodward, Guy; Bonada, Núria; Brown, Lee E; Death, Russell G; Durance, Isabelle; Gray, Clare; Hladyz, Sally; Ledger, Mark E; Milner, Alexander M; Ormerod, Steve J; Thompson, Ross M; Pawar, Samraat

    2016-05-19

    Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanistic framework for predicting potential impacts of environmental fluctuations on running-water ecosystems by scaling up effects of fluctuations from individuals to entire ecosystems. This framework requires integration of four key components: effects of the environment on individual metabolism, metabolic and biomechanical constraints on fluctuating species interactions, assembly dynamics of local food webs, and mapping the dynamics of the meta-community onto ecosystem function. We illustrate the framework by developing a mathematical model of environmental fluctuations on dynamically assembling food webs. We highlight (currently limited) empirical evidence for emerging insights and theoretical predictions. For example, widely supported predictions about the effects of environmental fluctuations are: high vulnerability of species with high per capita metabolic demands such as large-bodied ones at the top of food webs; simplification of food web network structure and impaired energetic transfer efficiency; and reduced resilience and top-down relative to bottom-up regulation of food web and ecosystem processes. We conclude by identifying key questions and challenges that need to be addressed to develop more accurate and predictive bio-assessments of the effects of fluctuations, and implications of fluctuations for management practices in an increasingly uncertain world. PMID:27114576

  15. The effects of climatic fluctuations and extreme events on running water ecosystems.

    Science.gov (United States)

    Woodward, Guy; Bonada, Núria; Brown, Lee E; Death, Russell G; Durance, Isabelle; Gray, Clare; Hladyz, Sally; Ledger, Mark E; Milner, Alexander M; Ormerod, Steve J; Thompson, Ross M; Pawar, Samraat

    2016-05-19

    Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanistic framework for predicting potential impacts of environmental fluctuations on running-water ecosystems by scaling up effects of fluctuations from individuals to entire ecosystems. This framework requires integration of four key components: effects of the environment on individual metabolism, metabolic and biomechanical constraints on fluctuating species interactions, assembly dynamics of local food webs, and mapping the dynamics of the meta-community onto ecosystem function. We illustrate the framework by developing a mathematical model of environmental fluctuations on dynamically assembling food webs. We highlight (currently limited) empirical evidence for emerging insights and theoretical predictions. For example, widely supported predictions about the effects of environmental fluctuations are: high vulnerability of species with high per capita metabolic demands such as large-bodied ones at the top of food webs; simplification of food web network structure and impaired energetic transfer efficiency; and reduced resilience and top-down relative to bottom-up regulation of food web and ecosystem processes. We conclude by identifying key questions and challenges that need to be addressed to develop more accurate and predictive bio-assessments of the effects of fluctuations, and implications of fluctuations for management practices in an increasingly uncertain world.

  16. Statoil`s exposure to oil price fluctuations: An analysis on investment level and stock price

    OpenAIRE

    Nåmdal, Synne Meling; Meling, Kristine

    2015-01-01

    In this thesis an econometric analysis of Statoil’s investment level and stock return has been performed, with purpose of examine the affect that fluctuations in the price of crude oil has on these variables. The results revealed that crude oil prices have a significant impact on Statoil´s stock returns, due to the direct impact the crude oil price has on Statoil’s cash flows. The investment level does not seem to be affected by either of the variables in the analysis, and this could indicate...

  17. Piston slap induced pressure fluctuation in the water coolant passage of an internal combustion engine

    Science.gov (United States)

    Ohta, Kazuhide; Wang, Xiaoyu; Saeki, Atsushi

    2016-02-01

    Liner cavitation is caused by water pressure fluctuation in the water coolant passage (WCP). When the negative pressure falls below the saturated vapor pressure, the impulsive pressure following the implosion of cavitation bubbles causes cavitation erosion of the wet cylinder liner surface. The present work establishes a numerical model for structural-acoustic coupling between the crankcase and the acoustic field in the WCP considering their dynamic characteristics. The coupling effect is evaluated through mutual interaction terms that are calculated from the mode shapes of the acoustic field and of the crankcase vibration on the boundary. Water pressure fluctuations in the WCP under the action of piston slap forces are predicted and the contributions of the uncoupled mode shapes of the crankcase and the acoustic field to the pressure waveform are analyzed. The influence of sound speed variations on the water pressure response is discussed, as well as the pressure on the thrust sides of the four cylinders.

  18. The westerly fluctuation and water vapor transport over the Qilian-Heihe valley

    Institute of Scientific and Technical Information of China (English)

    WANG; Keli; CHENG; Guodong; XIAO; Honglang

    2004-01-01

    The westerly fluctuation and the atmospheric water vapor transport over the Qilian-Heihe valley are analyzed and the results show that, in the water vapor transport stream field from Jun to September, this valley is in the westerly stream and the water vapor comes from westerlies water transport via the Black Sea and the Caspian Sea. The net water vapor transport is less net import and different from most areas of the northwest China. The interannual changes in water vapor transport over the valley arise from the westerly fluctuation, and have a positive relationship to the interannual changes in westerly wind speed. The cold air actions from the Mongol low pressure are the primary system that controls the westerly water vapor transport. Its action chain is that, the Mongol low pressure is strengthened → the circulation meridionality will be increased → the cold air will move southwards → the westerly will be stronger → the wind convergence of direction and speed will be stronger → the water vapor convergence transport will be increased → the local water vapor content will be increased. The interannual changes in atmospheric water vapor transport over the valley rely mainly on the convergence transport, but the effect of advection transport is less. The interannual changes of strong or weak westerly affect mainly the convergence transport, and then make the atmospheric water vapor net transport increase or decrease over the Qilian-Heihe valley.

  19. Reactor water level control system

    International Nuclear Information System (INIS)

    A BWR type reactor comprises a control valve disposed in a reactor water draining pipelines and undergoing an instruction to control the opening degree, an operation board having a setting device for generating the instruction and a control board for giving the instruction generated by the setting device to the control valve. The instruction is supplied from the setting device to the control valve by way of a control circuit to adjust the opening degree of the control valve thereby controlling the water level in the reactor. In addition, a controller generating an instruction independent of the setting device and a signal transmission channel for signal-transmitting the instruction independent of the control circuit are disposed, to connect the controller electrically to the signal transmission. The signal transmission channel and the control circuit are electrically connected to the control valve switchably with each other. Since instruction can be given to the control valve even at a periodical inspection or modification when the setting device and the control circuit can not be used, the reactor water level can be controlled automatically. Then, operator's working efficiency upon inspection can be improved remarkably. (N.H.)

  20. 三峡库区消落带不同高程桑树林地土壤抗蚀性及影响因素%Characteristics and soil anti-erodibility effects of mulberry forest lands at different altitudes of water-level fluctuation zone of the Three Gorges Reservoir

    Institute of Scientific and Technical Information of China (English)

    郭天雷; 史东梅; 胡雪琴; 黄先智; 蒋平

    2015-01-01

    消落带是典型的生态脆弱区,研究消落带土壤抗侵蚀特点对三峡库区水土流失防治具有重要意义。为了研究三峡库区消落带桑树林地土壤抗蚀性在不同高程处的差异,本文以典型消落带桑树林地为研究对象,采用土壤理化性质研究法对不同高程桑树林地土壤抗蚀性特征及其影响因素进行了分析。结果表明:1)不同高程桑树林地0~20 cm 土层土壤抗蚀性指数具有较大差异,表现为180 m(38.22%)>170 m(23.09%)>165 m (18.4%)>175 m(10.5%),且未淹没区(高程为180 m)大于淹没区(高程≤175 m);对于同一高程,表层(0~10 cm)土壤抗蚀性优于底层(10~20 cm)。2)土壤15个抗蚀性指标优化为F1、F2、F33个主成分,其土壤抗蚀性综合评价模型为F=0.655F1+0.236F2+0.109F3,评价结果表明不同高程桑树林地土壤抗蚀性大小为180 m>170 m>165 m>175 m。3)相关性分析表明土壤抗蚀性指数与土壤黏粒(0.25 mm水稳性团粒含量呈极显著正相关(P0.25 mm水稳性团粒和有机质是影响三峡库区消落带土壤抗蚀性的重要因子。研究结果可为三峡库区消落带不同区域土壤流失进行针对性防治提供重要科学依据。%Due to periodic wet and dry processes, water-level fluctuation zone of the reservoir area is typically ecologically fragile. It is therefore important for protection of the eco-environments of reservoir areas to control soil and water loss in such specifically fragile zones. Mulberry forest plots were selected in the water-level fluctuation zone of the Three Gorges Reservoir in September 2012 at four altitudes (165 m, 170 m, 175 m and 180 m), with no flooding at the 180 m altitude. Soil physio-chemical characteristics, anti-erodibility and the driving factors of mulberry forest lands at different altitudes were studied. The aim of the study was to explore soil anti-erodibility effect of mulberry forests at different altitudes. The study further provides scientific

  1. Fluctuations in Species-Level Protein Expression Occur during Element and Nutrient Cycling in the Subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, Michael J.; Wrighton, Kelly C.; Nicora, Carrie D.; Williams, Kenneth H.; McCue, Lee Ann; Handley, Kim M.; Miller, C. S.; Giloteaux, L.; Montgomery, A. P.; Lovley, Derek R.; Banfield, Jillian F.; Long, Philip E.; Lipton, Mary S.

    2013-03-05

    While microbial activities in environmental systems play a key role in the utilization and cycling of essential elements and compounds, microbial activity and growth frequently fluctuates in response to environmental stimuli and perturbations. To investigate these fluctuations within a saturated aquifer system, we monitored a carbon-stimulated in situ Geobacter population while iron reduction was occurring, using 16S rRNA abundances and high-resolution tandem mass spectrometry proteome measurements. Following carbon amendment, 16S rRNA analysis of temporally separated samples revealed the rapid enrichment of Geobacter-like environmental strains with strong similarity to G. bemidjiensis. Tandem mass spectrometry proteomics measurements suggest high carbon flux through Geobacter respiratory pathways, and the synthesis of anapleurotic four carbon compounds from acetyl-CoA via pyruvate ferredoxin oxidoreductase activity. Across a 40-day period where Fe(III) reduction was occurring, fluctuations in protein expression reflected changes in anabolic versus catabolic reactions, with increased levels of biosynthesis occurring soon after acetate arrival in the aquifer. In addition, localized shifts in nutrient limitation were inferred based on expression of nitrogenase enzymes and phosphate uptake proteins. These temporal data offer the first example of differing microbial protein expression associated with changing geochemical conditions in a subsurface environment.

  2. Fluctuations in species-level protein expression occur during element and nutrient cycling in the subsurface.

    Directory of Open Access Journals (Sweden)

    Michael J Wilkins

    Full Text Available While microbial activities in environmental systems play a key role in the utilization and cycling of essential elements and compounds, microbial activity and growth frequently fluctuates in response to environmental stimuli and perturbations. To investigate these fluctuations within a saturated aquifer system, we monitored a carbon-stimulated in situ Geobacter population while iron reduction was occurring, using 16S rRNA abundances and high-resolution tandem mass spectrometry proteome measurements. Following carbon amendment, 16S rRNA analysis of temporally separated samples revealed the rapid enrichment of Geobacter-like environmental strains with strong similarity to G. bemidjiensis. Tandem mass spectrometry proteomics measurements suggest high carbon flux through Geobacter respiratory pathways, and the synthesis of anapleurotic four carbon compounds from acetyl-CoA via pyruvate ferredoxin oxidoreductase activity. Across a 40-day period where Fe(III reduction was occurring, fluctuations in protein expression reflected changes in anabolic versus catabolic reactions, with increased levels of biosynthesis occurring soon after acetate arrival in the aquifer. In addition, localized shifts in nutrient limitation were inferred based on expression of nitrogenase enzymes and phosphate uptake proteins. These temporal data offer the first example of differing microbial protein expression associated with changing geochemical conditions in a subsurface environment.

  3. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

    OpenAIRE

    Lindhorst, K.; H. Vogel; S. Krastel; Wagner, B.; Hilgers, A.; Zander, A.; Schwenk, T.; Wessels, M.; Daut, G.

    2010-01-01

    Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60 m water depth. According t...

  4. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

    OpenAIRE

    Lindhorst, K.; Vogel, Hendrik; S. Krastel; Wagner, B.; Hilgers, A.; Zander, A.; Schwenk, T.; Wessels, M.; Daut, G.

    2010-01-01

    Abstract. Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60m water dep...

  5. Water Level Measurement in Floodplain using ALOS PALSAR

    OpenAIRE

    Won, Joong-Sun

    2011-01-01

    L-band interferometric SAR (InSAR) has been used to detect a relative water level change in the floodplain of the Tonle Sap, Cambodia. The goal of this research is a pattern and trend analysis of flooding around the Tonle Sap. The flood pattern over the Tonle Sap area during 2007-2011 has been examined using ALOS PALSAR to monitor the flood pattern, water level fluctuation and the area of flood around the Tonle Sap. Previous studies had shown L-band SAR interferometry is a useful method for t...

  6. Analytic Solutions and Their Errors of Groundwater Phreatic Line in Bank Slope under Reservoir Water Level Fluctuation%库水波动下库岸边坡地下水浸润线解析解及误差分析

    Institute of Scientific and Technical Information of China (English)

    胡庆; 李漪; 李恒; 胡凯锋; 郑德宾

    2013-01-01

    Although analytical method is a practical method in the calculation of phreatic line of groundwater in reservoir bank slope, it is based on certain assumptions and the linearization of the Boussinesq' s equation. Different mathematical models for the seepage of groundwater were established and then solved by analytical method or finite element method. By comparing the solutions to these different models, the errors caused by these assumptions and the linearization were analyzed. Results showed that both the errors caused by the linearization and the neglect of unsaturated seepage were greater than the error caused by assuming the reservoir bank is vertical, and all of them decreased with the increase of permeability coefficient. The error caused by the assumption of uniform water level changes could be ignored in the case of Three Gorges reservoir water scheduling. When calculating the groundwater phreatic line in reservoir bank slope, analytical method only applies to the case when the water level fluctuation amplitude is smaller than 30% of the aquifer thickness, the geotechnical structure is regular, and the soil has good permeability and simple structure.%解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解.针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律.结果表明:库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况.

  7. Empirical Research on Household Willingness and Its Caused Factors for Economic Compensation of Eco-fallow in the Water-level Fluctuation Zone of the Three Gorges Reservoir Area%三峡库区消落带农户生态休耕经济补偿意愿及影响因素研究

    Institute of Scientific and Technical Information of China (English)

    尹珂; 肖轶

    2015-01-01

    There is mainly slope land in the Three Gorges Reservoir, accounting for 68.8%of the total cultivated area, in which it has exceeded 25%that the slope is more than 25°. So the fundamental contradiction is intense after the reservoir storage, that is too many people and less land. When the rural resettlement have to make a choice between environmental protection and economic income, most people will choose the latter. Since unrea-sonable land use easily causes soil erosion and non-point source pollution, it will affect the water the reservoir environment security. According to the environmental impact of cultivation in the water-level fluctuation zone of Three Gorges Reservoir area, we established MNL regression to quantitative analyze the impact factors on the demand for an economic compensation of eco-fallow in order to provide recommendations, which is based on spot investigation of 247 households'willingness in Fuling district and Fengdu district, Chongqing city. The results indicate:1) There exists comparatively large differences amongst the household willingness on econom-ic compensation demands which is influenced by household aging, the low comparative profit and the nonfarm income; 2) The obvious influences factors on the economic compensation mechanism of eco-fallow include comparative benefit of eco-fallow, household population, annual household net income per capita, eco-fallow willingness index, expected value of economic compensation. It is conclude:most of surveyed households are relatively strong demand for economic compensation. From the origin, the main reason is that the immigration policy did not consider the future development needs and make compensation according to the market principle in the background of that time. Now many contradictions gradually exposed in practice, the land resource rapid-ly decrease after reservoir storage and the immigrants lose the original income channels which result in some of immigrants become the new poverty

  8. Autocorrelation in ultraviolet radiation measured at ground level using detrended fluctuation analysis

    Science.gov (United States)

    da Silva Filho, Paulo Cavalcante; da Silva, Francisco Raimundo; Corso, Gilberto

    2016-07-01

    In this study, we analyzed the autocorrelation among four ultraviolet (UV) radiation data sets obtained at 305 nm, 320 nm, 340 nm, and 380 nm. The data were recorded at ground level at the INPE climate station in Natal, RN, Brazil, which is a site close to the equator. The autocorrelations were computed by detrended fluctuation analysis (DFA) to estimate the index α. We found that the ​fluctuations in the UV radiation data were fractal, with scale-free behavior at a DFA index α ≃ 0.7. In addition, we performed a power law spectral analysis, which showed that the power spectrum exhibited a power law behavior with an exponent of β ≃ 0.45. Given that the theoretical result is β = 2 α - 1, these two results are in good agreement. Moreover, the application of the DFA ​method to the UV radiation data required detrending using a polynomial with an order of at least eight, which was related to the complex daily solar radiation curve obtained at ground level in a tropical region. The results indicated that the α exponent of UV radiation is similar to other climatic records such as air temperature, wind, or rain, but not solar activity.

  9. Forecasting monthly groundwater level fluctuations in coastal aquifers using hybrid Wavelet packet–Support vector regression

    Directory of Open Access Journals (Sweden)

    N. Sujay Raghavendra

    2015-12-01

    Full Text Available This research demonstrates the state-of-the-art capability of Wavelet packet analysis in improving the forecasting efficiency of Support vector regression (SVR through the development of a novel hybrid Wavelet packet–Support vector regression (WP–SVR model for forecasting monthly groundwater level fluctuations observed in three shallow unconfined coastal aquifers. The Sequential Minimal Optimization Algorithm-based SVR model is also employed for comparative study with WP–SVR model. The input variables used for modeling were monthly time series of total rainfall, average temperature, mean tide level, and past groundwater level observations recorded during the period 1996–2006 at three observation wells located near Mangalore, India. The Radial Basis function is employed as a kernel function during SVR modeling. Model parameters are calibrated using the first seven years of data, and the remaining three years data are used for model validation using various input combinations. The performance of both the SVR and WP–SVR models is assessed using different statistical indices. From the comparative result analysis of the developed models, it can be seen that WP–SVR model outperforms the classic SVR model in predicting groundwater levels at all the three well locations (e.g. NRMSE(WP–SVR = 7.14, NRMSE(SVR = 12.27; NSE(WP–SVR = 0.91, NSE(SVR = 0.8 during the test phase with respect to well location at Surathkal. Therefore, using the WP–SVR model is highly acceptable for modeling and forecasting of groundwater level fluctuations.

  10. Arrival-time fluctuations of coherent reflections from surface gravity water waves.

    Science.gov (United States)

    Badiey, Mohsen; Eickmeier, Justin; Song, Aijun

    2014-05-01

    Arrival time fluctuations of coherent reflections from surface gravity waves are examined. A two-dimensional ray model with an evolving rough sea surface is used to explain the mechanism and formation of the deterministic striation patterns due to the surface reflection. Arrival time predictions from the ray model match qualitatively well with the measurements from bidirectional acoustic transmissions in a water depth of 100 m. PMID:24815293

  11. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

    Directory of Open Access Journals (Sweden)

    K. Lindhorst

    2010-11-01

    Full Text Available Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60 m water depth. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35 m below the present water level occurred during Marine Isotope Stage (MIS 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sub-lacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly image several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water-filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid.

  12. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

    Science.gov (United States)

    Lindhorst, K.; Vogel, H.; Krastel, S.; Wagner, B.; Hilgers, A.; Zander, A.; Schwenk, T.; Wessels, M.; Daut, G.

    2010-11-01

    Ancient Lake Ohrid is a steep-sided, oligotrophic, karst lake that was tectonically formed most likely within the Pliocene and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 60 m water depth. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35 m below the present water level occurred during Marine Isotope Stage (MIS) 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sub-lacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly image several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water-filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid.

  13. [Seasonal fluctuations in fluoride content in waters of the Warta oxbow lake in Luboń].

    Science.gov (United States)

    Jezierska-Madziar, Maria; Pińskwar, Piotr; Golski, Janusz

    2004-01-01

    Studies were carried out in 2002-2003 at the Department of Inland Fishing and Aquaculture, Agricultural University of Poznań, on seasonal fluctuations in fluoride content in waters of the Warta oxbow lake in Luboń (52 degrees 19' N, 16 degrees 53' E). This reservoir has been loaded during several decades with fluorine compounds, originating from the deposits of post-crystallization lye of aluminum fluoride and fluorosilicic acid. The greatest amounts of fluorine compounds were deposited in the bottom sediments in the deepest part of the reservoir. On the basis of these two-year observations it was concluded that the concentration of fluoride in water is subject to significant variations (between 1.0 and 6.2 mg F(-)/L). The lowest fluoride concentration in water was recorded during vernal circulation. On the other hand, the highest values were found in the bottom water layer during the summer stagnation. Seasonal fluctuations in fluoride content in waters of the Warta oxbow lake were closely connected with mineralization in the bottom sediment as revealed by oxygen deficiencies in the bottom water layer. PMID:16892585

  14. Random fluctuations of snow accumulation over antarctica and their relation to sea level change

    Energy Technology Data Exchange (ETDEWEB)

    Remy, F.; Testut, L.; Legresy, B. [LEGOS (CNRS-CNES-UPS), Toulouse (France)

    2002-07-01

    Short-term changes in the volume of ice sheets as analyzed by radar altimetry may not be related to long-term climatic change. Indeed, the large relaxation time of an ice sheet induces a low-frequency response to random fluctuations of snow accumulation. However, the time scale of the response is big compared to the average human lifetime and the effect of these random fluctuations on sea level change may be important even if they are not linked to climatic change. In this study, the relaxation time of an ice sheet is expressed with respect to the ice thickness, surface slope and ice velocity. These parameters are deduced from the precise topography derived from the geodetic cycle of the ERS1 radar altimeter. The variance of the induced effect on ice elevation is found to be around 3 m over a 30-year scale and with a maximum of 10 m in Wilkes Land and in the western part of the West Antarctic ice sheet. Near the coast, this effect can mask a climatic signal and thus be critical for altimetric mass balance surveys. The estimated changes in Antarctica's elevation between the Seasat (1978) and ERS (1993) epochs could be explained at least partially by such processes. In terms of sea level change over the 30-year scale, the standard deviation of the induced effect is 8 {+-} 2.8 cm. Finally, we show that the probability of a present-day, induced sea level rise of between 0.5 and 1 mm/year over a 30-year time scale is estimated at 10% {+-} 10%, with coastal areas accounting for half of this signal. (orig.)

  15. Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans

    International Nuclear Information System (INIS)

    The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng 3H-labeled OTA (3.8 μCi). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T1/2 about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes. (orig.)

  16. Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans

    Energy Technology Data Exchange (ETDEWEB)

    Studer-Rohr, I. [Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland); Dept. of Food Science, Swiss Federal Inst. of Tech., Zurich (Switzerland); Schlatter, J. [Toxicology Section, Div. of Food Science, Swiss Federal Office of Public Health, Zurich (Switzerland); Dietrich, D.R. [Dept. of Environmental Toxicology, Univ. of Konstanz, Konstanz (Germany); Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland)

    2000-11-01

    The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng {sup 3}H-labeled OTA (3.8 {mu}Ci). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T{sub 1/2} about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes. (orig.)

  17. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

    Directory of Open Access Journals (Sweden)

    K. Lindhorst

    2010-05-01

    Full Text Available Ancient Lake Ohrid is a steep sided, oligotrophic, karst lake of likely Pliocene age and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 55 m. According to our data, significant lake level fluctuations with prominent lowstands of ca. 60 and 35 m below the present water level occurred during MIS 6 and MIS 5, respectively. The effect of these lowstands on biodiversity in most coastal parts of the lake is negligible, due to only small changes in lake surface area, coastline, and habitat. In contrast, biodiversity in shallower areas was more severely affected due to disconnection of today sub-lacustrine springs from the main water body. Multichannel seismic data from deeper parts of the lake clearly imaged several clinoform structures stacked on top of each other. These stacked clinoforms indicate significantly lower lake levels prior to MIS 6 and a stepwise rise of water level with intermittent stillstands since its existence as water filled body, which might have caused enhanced expansion of endemic species within Lake Ohrid.

  18. Investigation of temperature fluctuations caused by steam-water two-phase flow in pressurizer spray piping

    International Nuclear Information System (INIS)

    In a PWR plant, a steam-water two-phase flow may possibly exist in the pressurizer spray pipe under a normal operating condition since the flow rate of the spray water is not sufficient to fill the horizontal section of the pipe completely. Initiation of high cycle fatigue cracks is suspected to occur under such thermally stratified two phase flow conditions due to cyclic thermal stress fluctuations caused by oscillations of the water surface. Such oscillations cannot be detected by the measurement of temperature on outer surface of the pipe. In order to clarify the flow and thermal conditions in the pressurizer spray pipe and assess their impact on the pipe structure, an experiment was conducted for a steam-water flow at a low flow rate using a mock-up pressurizer spray pipe. The maximum temperature fluctuation of about 0.2 times of the steam-water temperature difference was observed at the inner wall around water surface in the test section. Visualization tests were conducted to investigate the temperature fluctuation phenomena. It was shown that the fluid temperature fluctuations were not caused by the waves on the water surface, but were caused by liquid temperature fluctuations in water layer below the interface. The influence of small amount of non-condensable gas dissolved in the reactor coolant on the liquid temperature fluctuation phenomena was investigated by injecting air into the experimental loop. The air injection attenuated the liquid temperature fluctuations in the water layer since the condensation was suppressed by the non-condensable gas. It is not expected that wall temperature fluctuation in the actual PWR plant may exceed the temperature equivalent to the fatigue limit stress amplitude when it is assumed to be proportional to the steam-water temperature difference. (author)

  19. Control of mould level fluctuation through the modification of steel composition

    Science.gov (United States)

    Li, Yang; Zhang, Xiao-huan; Lan, Peng; Zhang, Jia-quan

    2013-02-01

    Periodic mould level fluctuation (MLF) during slab casting is a bottleneck for upgrading the surface quality and casting speed especially for hypoperitectic (HP) or ultralow carbon steels. The uneven growth of the initially solidified shell is verified to be one of the important inducements to MLF due to related unsteady bulging in the secondary cooling zone. It is shown that the solidification mode of steels and the contraction behavior can be modified through chemical composition optimization within given composition limits. For high strength low alloy (HSLA) steels, the actual peritectic points calculated by Thermo-Calc software may change remarkably with the slight variations of alloying element contents. Accordingly, the narrow limit of chemical composition of HP steels through optimization is proven to be one of the effective factors to control the popular MLF phenomenon during slab casting.

  20. Optimal control of a qubit coupled to a two-level fluctuator

    CERN Document Server

    Rebentrost, P; Serban, I; Wilhelm, F K

    2006-01-01

    A central challenge for implementing quantum computing in the solid state is decoupling the qubits from the intrinsic noise of the material. We investigate limits of controllability for a paradigmatic model: A single qubit coupled to a two-level fluctuator exposed to a heat bath. We systematically search for optimal pulses using a generalization of the novel open system Gradient Ascent Pulse Engineering (GRAPE) algorithm. We show and explain that next to the known optimal bias point of this model, there are optimal shapes which refocus unwanted terms in the Hamiltonian. We study the limitations of control set by the decoherence properties in the fast flipping regime, which go beyond a simple random telegraph noise model. This can lead to a significant improvement of quantum operations in hostile environments.

  1. 基于GIS的长江三峡水库消落带生态类型划分及其特征%GIS-based division of ecological types and their characteristics of water-level-fluctuating zone in the Three Gorges Reservoir of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    雷波; 杨春华; 杨三明; 周玉; 张晟; 王业春

    2012-01-01

    By using GIS technology, and taking water level change, bank slope of reservoir, and small scale geomorphology as the environmental evaluation indicators, the water level elevation-slope and spatial geo-morphological maps of the Three Gorges Reservoir were drawn, based on the digital topographic map, and, through overlay analysis, the ecological types of water-level-fluctuating zone (WLFZ) in the Reservoir were classed. The ecological types of the WLFZ could be classified into 6 classes and 12 subclasses, including perennial submerged WLFZ (gentle slope and steep slope) , periodic submerged WLFZ (gentle slope and steep slope) , perennial non-submerged WLFZ (gentle slope and steep slope) , island WLFZ (submerged and non-submerged ) , lake basin-estuary-reservoir bay-reservoir tail WLFZ (lake basin, estuary, bay, and reservoir tail) , and valley WLFZ. The periodic submerged WLFZ, perennial non-submerged WLFZ, and lake basin-estuary-reservoir bay-reservoir tail WLFZ together accounted for 82. 2% of the entire WLFZ area, indicating that the three main ecological types should be artificial ecological restoration-based and supplemented by natural recovery, while the perennial submerged WLFZ, island WLFZ, and valley WLFZ accounted for 17.8% of the entire WLFZ area, which should be natural recovery-based and supplemented by artificial ecological restoration.%利用GIS技术,以水位高程变化、库岸坡度和小尺度地形地貌特征为依据,在数字地形图上,制作水位高程-坡度图和小尺度地形地貌图,通过图形叠加分析,对长江三峡水库消落带进行生态类型划分.结果表明:三峡水库消落带生态类型可划分为经常性水淹型(缓坡型、陡坡型)、半淹半露型(缓坡型、陡坡型)、经常性出露型(缓坡型、陡坡型)、岛屿型(常淹型、出露型)、湖盆-河口-库湾-库尾型(湖盆型、河口型、库湾型、库尾型)、峡谷型等6大类12个亚类;半淹半露型、经常性出露型和

  2. Cholesterol-induced suppression of membrane elastic fluctuations at the atomistic level.

    Science.gov (United States)

    Molugu, Trivikram R; Brown, Michael F

    2016-09-01

    Applications of solid-state NMR spectroscopy for investigating the influences of lipid-cholesterol interactions on membrane fluctuations are reviewed in this paper. Emphasis is placed on understanding the energy landscapes and fluctuations at an emergent atomistic level. Solid-state (2)H NMR spectroscopy directly measures residual quadrupolar couplings (RQCs) due to individual C-(2)H labeled segments of the lipid molecules. Moreover, residual dipolar couplings (RDCs) of (13)C-(1)H bonds are obtained in separated local-field NMR spectroscopy. The distributions of RQC or RDC values give nearly complete profiles of the order parameters as a function of acyl segment position. Measured equilibrium properties of glycerophospholipids and sphingolipids including their binary and tertiary mixtures with cholesterol show unequal mixing associated with liquid-ordered domains. The entropic loss upon addition of cholesterol to sphingolipids is less than for glycerophospholipids and may drive the formation of lipid rafts. In addition relaxation time measurements enable one to study the molecular dynamics over a wide time-scale range. For (2)H NMR the experimental spin-lattice (R1Z) relaxation rates follow a theoretical square-law dependence on segmental order parameters (SCD) due to collective slow dynamics over mesoscopic length scales. The functional dependence for the liquid-crystalline lipid membranes is indicative of viscoelastic properties as they emerge from atomistic-level interactions. A striking decrease in square-law slope upon addition of cholesterol denotes stiffening relative to the pure lipid bilayers that is diminished in the case of lanosterol. Measured equilibrium properties and relaxation rates infer opposite influences of cholesterol and detergents on collective dynamics and elasticity at an atomistic scale that potentially affects lipid raft formation in cellular membranes. PMID:27154600

  3. Investment Choice and Perceived Mating Intentions Regulated by External Resource Cues and Internal Fluctuation in Blood Glucose Levels

    Directory of Open Access Journals (Sweden)

    Li-Lin eRao

    2015-01-01

    Full Text Available We examined resource allocation priorities in the framework of an updated Maslow hierarchy of fundamental human needs. In Experiment 1, the participants in the food abundance priming condition viewing photos of high-calorie food allocated more money to savings than to spending. However, the participants preferred spending to savings under the condition of mating availability priming with romantic photographs. In Experiment 2, before and after drinking either water or a sugary beverage, fasting participants rated photos of a conversation between a man and a woman. Water drinking lowered the rating scores of mating intentions as well as blood glucose (BG levels. The sugary drink buffered this decline in sexual perceptivity. Overall, the change in BG levels was positively associated with changes in the ratings of mating intentions but was not associated with other likelihood ratings. These results suggest that both external cues of food and mating resources and internal BG fluctuation regulate the cognitive priority of physiological needs versus mate acquisition and retention.

  4. Water table fluctuation and its effects on vegetation in a semiarid environment

    Directory of Open Access Journals (Sweden)

    L. Duan

    2011-04-01

    Full Text Available A good understanding of water table fluctuation effects on vegetation is crucial for sustaining fragile hydrology and ecology of semiarid areas such as the Horqin Sandy Land (HSL in northern China, but such understanding is not well documented in literature. The objectives of this study were to examine spatio-temporal variations of water table and their effects on vegetation in a semiarid environment. A 9.71 km2 area within the HSL was chosen and well-instrumented to continuously measure hydrometeorologic parameters (e.g., water table. The area comprises of meadow lands and sandy dunes as well as transitional zones in between. In addition to those measured data, this study also used Landsat TM and MODIS imageries and meteorological data at a station near the study area. The spatio-temporal variations were examined using visual plots and contour maps, while the effects on vegetation were determined by overlaying a water table depth map with a vegetation index map derived from the MODIS imageries. The results indicated that water table was mainly dependent on local topography, localized geological settings, and human activities (e.g., reclamation. At annual and monthly scales, water table was mainly a function of precipitation and potential evapotranspiration. A region within the study area where depth to water table was smaller tended to have better (i.e., more dense and productive vegetation cover. Further, the results revealed that water table fluctuation was more sensitive for vegetations in the meadow lands than in the transitional zones, but it was least sensitive for vegetations in the sandy dunes.

  5. Water table fluctuation and its effects on vegetation in a semiarid environment

    Science.gov (United States)

    Duan, L.; Liu, T.; Wang, X.; Luo, Y.; Wang, W.; Liu, X.

    2011-04-01

    A good understanding of water table fluctuation effects on vegetation is crucial for sustaining fragile hydrology and ecology of semiarid areas such as the Horqin Sandy Land (HSL) in northern China, but such understanding is not well documented in literature. The objectives of this study were to examine spatio-temporal variations of water table and their effects on vegetation in a semiarid environment. A 9.71 km2 area within the HSL was chosen and well-instrumented to continuously measure hydrometeorologic parameters (e.g., water table). The area comprises of meadow lands and sandy dunes as well as transitional zones in between. In addition to those measured data, this study also used Landsat TM and MODIS imageries and meteorological data at a station near the study area. The spatio-temporal variations were examined using visual plots and contour maps, while the effects on vegetation were determined by overlaying a water table depth map with a vegetation index map derived from the MODIS imageries. The results indicated that water table was mainly dependent on local topography, localized geological settings, and human activities (e.g., reclamation). At annual and monthly scales, water table was mainly a function of precipitation and potential evapotranspiration. A region within the study area where depth to water table was smaller tended to have better (i.e., more dense and productive) vegetation cover. Further, the results revealed that water table fluctuation was more sensitive for vegetations in the meadow lands than in the transitional zones, but it was least sensitive for vegetations in the sandy dunes.

  6. Drought impact on water use efficiency and intra-annual density fluctuations in Erica arborea on Elba (Italy).

    Science.gov (United States)

    Battipaglia, Giovanna; DE Micco, Veronica; Brand, Willi A; Saurer, Matthias; Aronne, Giovanna; Linke, Petra; Cherubini, Paolo

    2014-02-01

    Erica arborea (L) is a widespread Mediterranean species, able to cope with water stress and colonize semiarid environments. The eco-physiological plasticity of this species was evaluated by studying plants growing at two sites with different soil moistures on the island of Elba (Italy), through dendrochronological, wood-anatomical analyses and stable isotopes measurements. Intra-annual density fluctuations (IADFs) were abundant in tree rings, and were identified as the key parameter to understand site-specific plant responses to water stress. Our findings showed that the formation of IADFs is mainly related to the high temperature, precipitation patterns and probably to soil water availability, which differs at the selected study sites. The recorded increase in the (13) C-derived intrinsic water use efficiency at the IADFs level was linked to reduced water loss rather than to increasing C assimilation. The variation in vessel size and the different absolute values of δ(18) O among trees growing at the two study sites underlined possible differences in stomatal control of water loss and possible differences in sources of water uptake. This approach not only helped monitor seasonal environmental differences through tree-ring width, but also added valuable information on E. arborea responses to drought and their ecological implications for Mediterranean vegetation dynamics.

  7. Characterization of Water Level Variability of the Main Ethiopian Rift Valley Lakes

    OpenAIRE

    Mulugeta Dadi Belete; Bernd Diekkrüger; Jackson Roehrig

    2015-01-01

    In this paper, the water level fluctuations of eight Ethiopian Rift Valley lakes were analyzed for their hydrological stability in terms of water level dynamics and their controlling factors. Long-term water balances and morphological nature of the lakes were used as bases for the analyses. Pettit’s homogeneity test and Mann–Kendall trend analysis were applied to test temporal variations of the lake levels. It is found that the hydrological stability of most of the Ethiopian Rift Valley lakes...

  8. Anandamide levels fluctuate in the bovine oviduct during the oestrous cycle.

    Directory of Open Access Journals (Sweden)

    Maria Gracia Gervasi

    Full Text Available Mammalian oviduct acts as a reservoir for spermatozoa and provides an environment in which they may compete for the opportunity to fertilize the oocyte. Whilst in the oviduct spermatozoa undergo capacitation essential for fertilization. Sperm-oviduct interaction is essential for sperm capacitation and is a tightly regulated process influenced by the local microenvironment. Previously we reported that the endocannabinoid anandamide (AEA regulates sperm release from epithelial oviductal cells by promoting sperm capacitation. The aims of this work were to measure the AEA content and to characterize the main AEA metabolic pathway in the bovine oviduct and determine how these change through the oestrous cycle. In this study, the levels of AEA and two other N-acylethanolamines, N-oleoylethanolamine and N-palmitoylethanolamine, were measured in bovine oviduct collected during different stages of oestrous cycle by ultra high performance liquid chromatography tandem mass spectrometry. Results indicated that intracellular oviductal epithelial levels of all three N-acylethanolamines fluctuate during oestrous cycle. Anandamide from oviductal fluid also varied during oestrous cycle, with the highest values detected during the periovulatory period. Endocannabinoid levels from ipsilateral oviduct to ovulation were higher than those detected in the contralateral one, suggesting that levels of oviductal AEA may be regulated by ovarian hormones. The expression and localization of N-acylethanolamines metabolizing enzymes in bovine oviduct were also determined by RT-PCR, Western blot, and immunohistochemistry but no change was found during the oestrous cycle. Furthermore, nanomolar levels of AEA were detected in follicular fluids, suggesting that during ovulation the mature follicle may contribute to oviductal AEA levels to create an endocannabinoid gradient conducive to the regulation of sperm function for successful fertilization.

  9. Pleistocene sea-level fluctuations and human evolution on the southern coastal plain of South Africa

    Science.gov (United States)

    Compton, John S.

    2011-03-01

    Humans evolved in Africa, but where and how remain unclear. Here it is proposed that the southern coastal plain (SCP) of South Africa may have served as a geographical point of origin through periodic expansion and contraction (isolation) in response to glacial/interglacial changes in sea level and climate. During Pleistocene interglacial highstands when sea level was above -75 m human populations were isolated for periods of 360-3400 25-yr generations on the SCP by the rugged mountains of the Cape Fold Belt, climate and vegetation barriers. The SCP expands five-fold as sea level falls from -75 to -120 m during glacial maxima to form a continuous, unobstructed coastal plain accessible to the interior. An expanded and wet glacial SCP may have served as a refuge to humans and large migratory herds and resulted in the mixing of previously isolated groups. The expansive glacial SCP habitat abruptly contracts, by as much as one-third in 300 yr, during the rapid rise in sea level associated with glacial terminations. Rapid flooding may have increased population density and competition on the SCP to select for humans who expanded their diet to include marine resources or hunted large animals. Successful adaptations developed on an isolated SCP are predicted to widely disperse during glacial terminations when the SCP rapidly contracts or during the initial opening of the SCP in the transition to glacial maxima. The hypothesis that periodic expansion and contraction of the SCP, as well as the coastal plain of North Africa, contributed to the stepwise origin of our species over the last 800 thousand years (kyr) is evaluated by comparing the archeological, DNA and sea-level records. These records generally support the hypothesis, but more complete and well dated records are required to resolve the extent to which sea-level fluctuations influenced the complex history of human evolution.

  10. Decline in water level boosts cyanobacteria dominance in subtropical reservoirs.

    Science.gov (United States)

    Yang, Jun; Lv, Hong; Yang, Jun; Liu, Lemian; Yu, Xiaoqing; Chen, Huihuang

    2016-07-01

    Globally aquatic ecosystems are likely to become more vulnerable to extreme water fluctuation rates due to the combined effects of climate change and human activity. However, relatively little is known about the importance of water level fluctuations (WLF) as a predictor of phytoplankton community shifts in subtropical reservoirs. In this study, we used one year of data (2010-2011) from four subtropical reservoirs of southeast China to quantify the effects of WLF and other environmental variables on phytoplankton and cyanobacteria dynamics. The reservoirs showed an apparent switch between a turbid state dominated by cyanobacteria and a clear state dominated by other non-cyanobacterial taxa (e.g., diatoms, green algae). Cyanobacterial dominance decreased, or increased, following marked changes in water level. Multiple regression analysis demonstrated that pH, euphotic depth, WLF, and total phosphorus provided the best model and explained 30.8% of the variance in cyanobacteria biomass. Path analysis showed that positive WLF (i.e. an increase in water level) can reduce the cyanobacteria biomass either directly by a dilution effect or indirectly by modifying the limnological conditions of the reservoirs in complex pathways. To control the risk of cyanobacterial dominance or blooms, WLF should be targeted to be above +2m/month; that is an increase in water level of 2m or more. Given that WLF is likely to be of more frequent occurrence under future predicted conditions of climate variability and human activity, water level management can be widely used in small and medium-sized reservoirs to prevent the toxic cyanobacterial blooms and to protect the ecosystem integrity or functions. PMID:27016690

  11. On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water.

    Science.gov (United States)

    Carof, Antoine; Salanne, Mathieu; Charpentier, Thibault; Rotenberg, Benjamin

    2015-11-21

    Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as (7)Li(+), (23)Na(+), (25)Mg(2+), (35)Cl(-), (39)K(+), or (133)Cs(+). Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion. PMID:26590539

  12. Energy distribution and local fluctuations in strongly coupled open quantum systems: The extended resonant level model

    Science.gov (United States)

    Ochoa, Maicol A.; Bruch, Anton; Nitzan, Abraham

    2016-07-01

    We study the energy distribution in the extended resonant level model at equilibrium. Previous investigations [Phys. Rev. B 89, 161306 (2014), 10.1103/PhysRevB.89.161306; Phys. Rev. B 93, 115318 (2016), 10.1103/PhysRevB.93.115318] have found, for a resonant electronic level interacting with a thermal free-electron wide-band bath, that the expectation value for the energy of the interacting subsystem can be correctly calculated by considering a symmetric splitting of the interaction Hamiltonian between the subsystem and the bath. However, the general implications of this approach were questioned [Phys. Rev. B 92, 235440 (2015), 10.1103/PhysRevB.92.235440]. Here, we show that, already at equilibrium, such splitting fails to describe the energy fluctuations, as measured here by the second and third central moments (namely, width and skewness) of the energy distribution. Furthermore, we find that when the wide-band approximation does not hold, no splitting of the system-bath interaction can describe the system thermodynamics. We conclude that in general no proper division subsystem of the Hamiltonian of the composite system can account for the energy distribution of the subsystem. This also implies that the thermodynamic effects due to local changes in the subsystem cannot in general be described by such splitting.

  13. Isotopes reveal fluctuation in trophic levels of estuarine organisms, in space and time

    Science.gov (United States)

    Vinagre, C.; Salgado, J. P.; Mendonça, V.; Cabral, H.; Costa, M. J.

    2012-08-01

    The estimation of the trophic level (TL) occupied by organisms in estuarine food webs, based on isotopic analysis, is generally done only for one season or averaged among seasons and sites. This does not allow the observation of possible alterations of TL in time and space. As estuaries are highly dynamic environments, it is plausible that the TLs of many of its organisms are not static, like usually portrayed in food web diagrams, but fluctuate in space and time. The TLs of marine juvenile fish, resident fish, shrimp, polychaetes, bivalves and amphipods were determined isotopically, in the Tagus estuary. Sampling was carried out in two nursery areas at each season. Significant changes in TL were observed, in space and time, for the vast majority of the organisms. A drop in TL in summer was observed for various species. The high availability of microalgae and macroalgae in summer may be the cause for this drop, which mainly affects low TL omnivores. These omnivores may opportunistically increase the proportion of primary producers in their diet, thus lowering their mean TL. Such an effect seems to cascade to secondary consumers, like Solea senegalensis and Pomatoschistus microps, which also presented a drop in TL in summer. This study also revealed that organisms that have been considered to be mainly primary consumers, like Liza ramada, and Scrobicularia plana, can actually assume considerably higher TLs seasonally, placing them as secondary consumers.

  14. Alluvial deposition and lake-level fluctuations forced by Late Quaternary climate change: the Dead Sea case example

    Science.gov (United States)

    Klinger, Y.; Avouac, J. P.; Bourles, D.; Tisnerat, N.

    2003-11-01

    Based on geomorphic observations, we discuss lake-level fluctuations, alluvial deposition and river entrenchment in the Dead Sea-Wadi Araba area. The bulk of alluvium in the northern Wadi Araba was probably deposited before the Lisan period of lake transgression that started at about 70 kyears B.P. The lake reached a maximum elevation about 150 m below sea level (b.s.l.), possibly around 15 cal. kyears B.P. as indicated by the highest preserved beach ridges. Cosmogenic exposure dates show that the ridge material consists mainly of remobilized Pleistocene gravel indicating little sediment supply during most of the Lisan period. During this period, a reduced sediment flux fed subaquatic fan deltas along the margin of the Dead Sea. Wetter conditions settled at the end of this period, the water level rose to about 280 m b.s.l. around 15 kyears B.P. and prevailed in the early Holocene (10.5-7 cal. kyears B.P.). Following that humid period, the lake level dropped and two major episodes of fluvial aggradation occurred during periods of relative low lake level. The first aggradational episode took place between about 7.0 and 6.2 cal. kyears B.P. Beach bars indicate a subsequent lake transgression between 6.2 and 4.4 kyears B.P. up to 350 m b.s.l. The second aggradational episode happened between 4.4 and 2.0 cal. kyears B.P., and was also followed by a late transgression up to 375 m b.s.l., dated to 1960-1715 cal. years B.P. The correlation between low lake level and fluvial aggradation is taken to reflect the synchronous change of the fluvial regime and of the lake hydrologic balance, forced by climate changes, rather than a base-level control. We also exclude large tectonic forcing on fan emplacement and river entrenchment. Alluviation appears in this setting as a very irregular process, characterized by long periods of quiescence alternating with periods of fan build-up, reflecting the transient response of the water drainage system to climate change.

  15. Fluctuations of sea water temperature based on nannofloral changes during the Middle to Late Miocene, Adana Basin, Turkey

    OpenAIRE

    SINACI, Manolya

    2013-01-01

    Some nannoplankton species are sensitive to water temperatures. While Coccolithus pelagicus and Reticulofenestra gelida indicate cooler water conditions, the genera Discoaster and Sphenolithus and Calcidiscus leptoporus are indicative of warmer water environments. This paper focuses on relative fluctuation of sea water temperatures during the Middle and Late Miocene, emphasised by cold and warm nannofossil changes in abundance in 2 wells. At the A-1 well in the Middle Miocene, the total abund...

  16. On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water

    Energy Technology Data Exchange (ETDEWEB)

    Carof, Antoine; Salanne, Mathieu; Rotenberg, Benjamin, E-mail: benjamin.rotenberg@upmc.fr [Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire PHENIX, Case 51, 4 Place Jussieu, F-75005 Paris (France); Charpentier, Thibault [CEA, IRAMIS, NIMBE, LSDRM, UMR CEA-CNRS 3685, F-91191 Gif-sur-Yvette Cedex (France)

    2015-11-21

    Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as {sup 7}Li{sup +}, {sup 23}Na{sup +}, {sup 25}Mg{sup 2+}, {sup 35}Cl{sup −}, {sup 39}K{sup +}, or {sup 133}Cs{sup +}. Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion.

  17. FLUCTUATION EFFECT OF EQUILIBRIUM MOISTURE CONTENT OF LOW SUBGRADE UNDER HIGH GROUNDWATER LEVEL IN HOT AND HUMID CLIMATIC REGIONS

    Directory of Open Access Journals (Sweden)

    Que Yun

    2016-05-01

    Full Text Available In order to reveal the fluctuation effect of equilibrium moisture content of low subgrade in hot and humid climatic regions, the effect of temperature on the fluctuation of the equilibrium moisture content of subgrade was analysed. Taking the typical climate and the subgrade soil in Fujian province as an example, three technological methods - theoretical analysis, numerical simulation and indoor simulation experiment - were adopted in the investigation of the fluctuation effect of equilibrium moisture content of subgrade. The results show that, computing results from the formula of the equilibrium moisture content of subgrade, the numerical simulation results are closer to each other in consideration of the temperature effect. The test results can not reflect the relationship between the equilibrium moisture content and the height of embankment. The maximum fluctuation range of the equilibrium moisture content of the cement concrete pavement is less than 2 percent in Fujian area, and this phenomenon presents the effect of the moist-hot climate on the equilibrium moisture content. Equilibrium moisture content presents a declining trend with the increment of the temperature and the compactness. So, if matric potential considering temperature indirectly reflects the influence of thermal potential, then the equilibrium moisture content of low subgrade under high groundwater level can be estimated approximately. The fluctuation range of equilibrium moisture content in different layers of subgrade can be reduced effectively with the increment of the roadbed compaction degree.

  18. 重复淹水对三峡库区消落带菖蒲植被生长发育的影响%Influence of the Repeated Flooding on Growth and Development of Acorus calamus Vegetation in Water-level-fluctuation Zone of the Three Gorges Reservoir

    Institute of Scientific and Technical Information of China (English)

    李强

    2012-01-01

    [目的]研究重复淹水对三峡库区消落带菖蒲植被生长发育的影响.[方法]分别于2009年9月和2010年9月在无光条件下将菖蒲植株完全淹水,并分别于翌年3、4月将植株露水(分别记为S1、S2、S'1、S'2),统计植株数,并于5月7日统计各组植株的叶片数,测定叶长、叶宽及叶片的快速光响应曲线.[结果]无光、重复淹水显著抑制了植株的萌发,与对照相较,S'1和S'2组萌发形成的植株数分别降低了38.9%、33.3%,差异显著;并显著降低了植株的存活率,与第1次淹水相较,S'2组植株露水时,植株数降低了16.7%(P<0.05).2次淹水均促进了植株叶片的伸长,抑制了植株叶宽的增加,除S1和S'1组外,2次淹水均显著抑制了植株叶片的形成.再次淹水后,植株的株叶长显著降低,S'1和S'2组的株叶长分别比上年低50.6%、36.9%,差异显著;总叶片数显著减少,S'1和S'2组总叶片数分别仅为对照的63.1%、38.5%,差异显著;与第1次淹水相较,对照总叶长显著增加,而S'2组总叶长显著降低.S'1组相对电子传递速率(rETR)的光响应能力与对照差异不显著,S'2组rETRmax显著低于对照,且S'1和S'2组热耗散系数(NPQ)显著降低,表明菖蒲植株具有较强的光响应恢复能力,但是热耗散能力恢复较慢.[结论]在无光条件下,重复淹水会抑制菖蒲植株的生长及种群恢复.%[Objective] The research aimed to study influence of the repeated flooding on growth and development of A. calamus in water-level-fluctuation zone of the Three Gorges Reservoir. [ Method]A. calamus plants were exposed to water under the dark conditions respectively in September 2009 and September 2010. Then,they were taken away from the water,and grew in natural conditions in the following March and A-pril respectively (marked as S1,S2,S' 1 and S'2). The plant number was conducted statistics respectively. On May 7,the leaf number was made statistics. Length,width and

  19. Geometric and energetic considerations of surface fluctuations during ion transfer across the water-immiscible organic liquid interface

    Science.gov (United States)

    Karnes, John J.; Benjamin, Ilan

    2016-07-01

    Molecular dynamics simulations and umbrella sampling free energy calculations are used to examine the thermodynamics, energetics, and structural fluctuations that accompany the transfer of a small hydrophilic ion (Cl-) across the water/nitrobenzene interface. By examining several constrained interface structures, we isolate the energetic costs of interfacial deformation and co-transfer of hydration waters during the ion transfer. The process is monitored using both energy-based solvation coordinates and a geometric coordinate recently introduced by Morita and co-workers to describe surface fluctuations. Our simulations show that these coordinates provide a complimentary description of the water surface fluctuations during the transfer and are necessary for elucidating the mechanism of the ion transfer.

  20. Some Examples Of Water Resources Variability In The Context Of Climatic Fluctuations

    Science.gov (United States)

    Laignel, B.; Massei, N.; Rossi, A.; Mesquita, J.; Slimani, S.

    2008-12-01

    The determination of the impact of climate change on hydrological systems and their water resource constitutes a major stake of the 21st century to which the scientists must answer. First of all, it is necessary to understand how climate are expressed in the hydrosystems. For several years, the M2C laboratory of the University of Rouen has tried to answer this question by working within the framework of many regional, national and international programs as well as PhD works. Those studies involve analyses of hydrological systems located: (1) in various climatic and geomorphological contexts on both sides of the Atlantic Ocean, (2) in various hydrological compartments (surface and ground water), (3) at various spatial scales (watersheds smaller than 1000 km2 and large rivers). The approach consists in studying the long-term changes, oscillations and fluctuations of hydrologic variables by the analysis of time series (precipitation, discharge, piezometry), in particular by means of signal analysis and processing methods. The studied hydrosystems are small watersheds and aquifer in Haute- Normandie, the Seine river (NW France), north-african watersheds (W Morocco and N Algeria), small watersheds and aquifer in Texas, the Colorado river (Texas) and the Mississippi river. Although the identification of structured variations might be uneasy - sometimes just impossible - in raw data, wavelet analysis, for instance, makes it possible to detect localized energetic structures and possible periodicities in all the studied hydrosystems and to quantify them. In many surface hydrosystems we note an intensification of the annual energy band which corresponds to the hydrological cycle. In the NW of France and North Africa, we observe 2-3-year and 5-7-year modes which could be linearly related to fluctuations in the NAO using wavelet coherence. In the USA, we notice similar 2- 3-year and 5-7-year modes that might be possibly related to the characteristic 2-4-year and 4-8-year of

  1. 自然光照对淹水条件下三峡库区消落带典型土壤磷释放影响%Effects of Light Irradiation on Phosphorous Releases from Typical Submerged Soils of Water-Level Fluctuation Zones of Three Gorges Reservoirs Areas

    Institute of Scientific and Technical Information of China (English)

    郭念; 江韬; 魏世强; 闫金龙; 梁俭; 卢松; 高洁

    2014-01-01

    为研究淹水条件下光照对土-水界面磷释放的影响,以三峡库区消落带典型土壤为对象,通过室内自然光照试验,讨论了铁还原及有机质降解对磷释放的影响,分析光照对淹水土壤磷释放的影响机制.结果表明,光照对淹水土壤磷释放存在一定程度的抑制作用,光照作用下淹水紫色潮土上覆水体中 TP 浓度范围为0.018~0.033 mg·L -1,避光处理为0.02~0.057 mg·L -1,灰棕紫泥光照下 TP 浓度范围为0.028~0.045 mg·L -1,避光处理为0.04~0.084 mg·L -1.光照引起淹水土壤中铁氧化物的变化可能是光照抑制磷释放的重要原因.光照导致土壤中铁氧化物饱和程度降低,铁还原和无定形铁生成受阻进一步加深了光照对磷释放的抑制影响. CO2和 CH4反映淹水土壤有机质分解情况,光照降低有机碳的转化效率,加速土壤中无机电子受体的消耗,解释了光照作用下铁氧化物的变化.由此可见,光照对淹水土壤磷释放的抑制与淹水土壤中铁还原和有机质分解密切相关.%For understanding the impact of light irradiation on the phosphorus ( P) releases from soil-water interface, two types of typical soils sampled from water-level fluctuation zones of Three Gorges Reservoir areas were selected as research objectives, and simulated light irradiation experiment in lab was conducted for unveiling the underlying mechanisms of P releases from submerged soils in the presence of light irradiation. The results showed that light irradiation could inhibit P releases from submerged soils by a certain degree. Under light condition, total P (TP) concentrations in underlying water of submerged purple soil ranged from 0. 018 to 0. 033 mg·L - 1 , as compared to the range of 0. 02-0. 057 mg·L - 1 in darkness treatment. Additionally, for gray-brown purple soil, TP was in a range of 0. 028-0. 045 mg·L - 1 when light irradiated, but in the range of 0. 04-0. 084 mg·L - 1 under darkness condition

  2. Phosphorus speciation and physical-chemical characteristics in the soils of water- level-fluctuating zone in the central distirict of Three Gorges Reservoir area%三峡水库消落区土壤理化特征及磷赋存形态研究

    Institute of Scientific and Technical Information of China (English)

    张彬; 方芳; 陈猷鹏; 李哲; 郭劲松; 黄轩民

    2012-01-01

    The contents of different phosphorus forms in the soils of water-level-fluctuating zone (WLFZ) from the Three Gorges Reservior were measured by using the standard measurement and test (SMT) procedure of phosphorus forms in freshwater sediments. Correlation coefficients were analyzed between phosphorus forms and sample physical-chemical characteristics, including total nitrogen (TN) , soluble organic matter ( SOM), pH, and oxidationreduction potential (ORP). The results indicated that the total phosphorus (TP) content in soil varied from 0.28 g·kg-1to 1.32 g·kg-1, and the average content was 0.63 g·kg-1. The average inorganic P (IP) and organic P (OP) in soil were 0.46 g·kg-1 and 0. 13 g·kg-1 , accounting for 72.3% and 21.7% of TP, respectively. The dominated phosphorus forms in the soil was IP. In terms of the range of different phosphorus forms content and relative content, the formation of phosphorus in the soil was in the descending order of Ca-P 〉 OP 〉 Fe/A1-P. The increase in surface soil TP content was mainly due to Ca-P and OP. The content of active phosphorus ( Fe/A1-P + OP) in soils of WLFZ ranged from 0.04 g·kg-1to 0. 39 g·kg-1 , with the average of 0.20 g·kg-1 accounting for 33.0% of active phosphorus in TP. The active phosphorus in soils of WLFZ would become potential pollution sources of water under favorable environmental conditions. Therefore, the potential impact of phosphorus on water eutrophication in soils of WLFZ could not be neglected. Positive correlation exists among the contents of TP, IP and Ca-P, between OP and Fe/AI-P, TN and SOM, and between Fe/A1-P and TN. All these results indicated that OP, Fe/A1-P, TN and SOM came from the same source, and Ca-P was the main existing form of IP and TP. On the other hand, OP was also significantly and positively correlated to pH, while negatively correlated to ORP, suggesting that the content and distribution of OP were affected by pH and ORP. Keywords

  3. Spatiotemporal patterns of water table fluctuations and evapotranspiration induced by riparian vegetation in a semiarid area

    Science.gov (United States)

    Yue, Weifeng; Wang, Tiejun; Franz, Trenton E.; Chen, Xunhong

    2016-03-01

    Groundwater evapotranspiration (ETg) links various ecohydrological processes and is an important component in regional water budgets. In this study, an extensive monitoring network was established in a semiarid riparian area to investigate various controls on the spatiotemporal pattern of water table fluctuations (WTFs) and ETg induced by riparian vegetation. Along a vegetation gradient (˜1200 m), diurnal WTFs were observed during a growing season in areas covered by woody species (Populus sect. Aigeiros and Juniperus virginiana) and wet slough vegetation (Panicum virgatum and Bromus inermis) with deeper root systems; whereas, no diurnal WTFs were found in the middle section with shallower-rooted grasses (Poa pratensis and Carex sp.). The occurrence of diurnal WTFs was related to temperature-controlled plant phenology at seasonal scales and to radiation at subdaily scales. Daily ETg in the mid-growing season was calculated using the White method. The results revealed that depth to water table (DTWT) was the dominant control on ETg, followed by potential evapotranspiration (ETp). By combining the effects of DTWT and ETp, it was found that at shallower depths, ETg was more responsive to changes in ETp, due to the closer linkage of land surface processes with shallower groundwater. Finally, exponential relationships between ETg/ETp and DTWT were obtained at the study site, although those relationships varied considerably across the sites. This study demonstrates the complex interactions of WTFs and ETg with surrounding environmental variables and provides further insight into modeling ETg over different time scales and riparian vegetation.

  4. Stochastic modelling of intermittent fluctuations in the scrape-off layer: Correlations, distributions, level crossings, and moment estimation

    Science.gov (United States)

    Garcia, O. E.; Kube, R.; Theodorsen, A.; Pécseli, H. L.

    2016-05-01

    A stochastic model is presented for intermittent fluctuations in the scrape-off layer of magnetically confined plasmas. The fluctuations in the plasma density are modeled by a super-position of uncorrelated pulses with fixed shape and duration, describing radial motion of blob-like structures. In the case of an exponential pulse shape and exponentially distributed pulse amplitudes, predictions are given for the lowest order moments, probability density function, auto-correlation function, level crossings, and average times for periods spent above and below a given threshold level. Also, the mean squared errors on estimators of sample mean and variance for realizations of the process by finite time series are obtained. These results are discussed in the context of single-point measurements of fluctuations in the scrape-off layer, broad density profiles, and implications for plasma-wall interactions due to the transient transport events in fusion grade plasmas. The results may also have wide applications for modelling fluctuations in other magnetized plasmas such as basic laboratory experiments and ionospheric irregularities.

  5. Impact of scaled-down on dissolved oxygen fluctuations at different levels of the lipase synthesis pathway of Yarrowia lipolytica

    Directory of Open Access Journals (Sweden)

    Delvigne, F.

    2010-01-01

    Full Text Available The impact of the fluctuations in dissolved oxygen tension (DOT on the lipase production by Yarrowia lipolytica has been investigated in a scale-down reactor (SDR. This bioreactor comprises a 20 l agitated vessel with an automatic valve controlling the opening and closure of the air flow line. This kind of scale-down apparatus is used in order to generate DOT gradients encountered in large-scale, while maintaining the other environmental conditions constant. The impact of DOT fluctuations has been estimated at three levels of the lipase synthesis machinery: lipase gene expression, lipase translation, lipase excretion to the extracellular medium. Among these levels, the performance of lipase production under oscillating DOT was significantly affected at the lipase gene expression level.

  6. Observing plants dealing with soil water stress: Daily soil moisture fluctuations derived from polymer tensiometers

    Science.gov (United States)

    van der Ploeg, Martine; de Rooij, Gerrit

    2014-05-01

    Periods of soil water deficit often occur within a plant's life cycle, even in temperate deciduous and rain forests (Wilson et al. 2001, Grace 1999). Various experiments have shown that roots are able to sense the distribution of water in the soil, and produce signals that trigger changes in leaf expansion rate and stomatal conductance (Blackman and Davies 1985, Gollan et al. 1986, Gowing et al. 1990 Davies and Zhang 1991, Mansfield and De Silva 1994, Sadras and Milroy 1996). Partitioning of water and air in the soil, solute distribution in soil water, water flow through the soil, and water availability for plants can be determined according to the distribution of the soil water potential (e.g. Schröder et al. 2013, Kool et al. 2014). Understanding plant water uptake under dry conditions has been compromised by hydrological instrumentation with low accuracy in dry soils due to signal attenuation, or a compromised measurement range (Whalley et al. 2013). Development of polymer tensiometers makes it possible to study the soil water potential over a range meaningful for studying plant responses to water stress (Bakker et al. 2007, Van der Ploeg et al. 2008, 2010). Polymer tensiometer data obtained from a lysimeter experiment (Van der Ploeg et al. 2008) were used to analyse day-night fluctuations of soil moisture in the vicinity of maize roots. To do so, three polymer tensiometers placed in the middle of the lysimeter from a control, dry and very dry treatment (one lysimeter per treatment) were used to calculate water content changes over 12 hours. These 12 hours corresponded with the operation of the growing light. Soil water potential measurements in the hour before the growing light was turned on or off were averaged. The averaged value was used as input for the van Genuchten (1980) model. Parameters for the model were obtained from laboratory determination of water retention, with a separate model parameterization for each lysimeter setup. Results show daily

  7. Evaluation of the Chemcatcher and DGT passive samplers for monitoring metals with highly fluctuating water concentrations.

    Science.gov (United States)

    Allan, Ian J; Knutsson, Jesper; Guigues, Nathalie; Mills, Graham A; Fouillac, Anne-Marie; Greenwood, Richard

    2007-07-01

    Passive sampling devices accumulate chemicals continuously from water and can provide time weighted average (TWA) concentrations of pollutants over the exposure period. Hence, they offer a number of advantages over other conventional monitoring techniques such as spot or grab sampling. The diffusive gradient in thin film (DGT) and the Chemcatcher passive samplers can be used to provide TWA concentrations of labile metals, but the approaches to their calibration differ. DGT uses diffusion coefficients of metals in the hydrogel layer, whereas Chemcatcher uses metal specific uptake rates, with both sets of values obtained under controlled laboratory conditions with constant aqueous metal concentrations. However, little is known of how such samplers respond to fluctuating concentrations. We evaluated the responsiveness of these two passive sampling devices to rapidly changing concentrations of Cd, Cu, Ni, Pb and Zn in natural freshwater, over a relatively short deployment time. Maximum metal concentrations in water were varied between 70 and 140 microg L(-1). Experiments were carried out in a tank with a rotating carousel system and filled with Meuse river water, allowing a degree of control over experimental conditions while using natural river water. Fluctuating concentrations were obtained by stepwise addition of standard solutions of the metals. The reliability and accuracy of the TWA concentrations measured by the samplers were assessed by comparison with concentrations of the metals in spot samples of water taken regularly over the deployment period. The spot samples of water were either unfiltered (total), filtered (0.45 microm) or ultrafiltered (5 kDa). Predictive speciation modelling using the visual MINTEQ programme was also undertaken. There was reasonable agreement between the TWA concentrations of Cd and Ni obtained with Chemcatcher and DGT and the total Cd and Ni concentrations measured in repeated unfiltered spot samples. For elements (i.e. Cu, Pb, Zn

  8. Systems-level modeling the effects of arsenic exposure with sequential pulsed and fluctuating patterns for tilapia and freshwater clam

    International Nuclear Information System (INIS)

    The purpose of this paper was to use quantitative systems-level approach employing biotic ligand model based threshold damage model to examine physiological responses of tilapia and freshwater clam to sequential pulsed and fluctuating arsenic concentrations. We tested present model and triggering mechanisms by carrying out a series of modeling experiments where we used periodic pulses and sine-wave as featured exposures. Our results indicate that changes in the dominant frequencies and pulse timing can shift the safe rate distributions for tilapia, but not for that of freshwater clam. We found that tilapia increase bioenergetic costs to maintain the acclimation during pulsed and sine-wave exposures. Our ability to predict the consequences of physiological variation under time-varying exposure patterns has also implications for optimizing species growing, cultivation strategies, and risk assessment in realistic situations. - Systems-level modeling the pulsed and fluctuating arsenic exposures.

  9. Seasonal fluctuations in water repellency and infiltration in a sandy loam soil after a forest fire in Galicia (NW Spain

    Directory of Open Access Journals (Sweden)

    M. Rodríguez-Alleres

    2013-05-01

    Full Text Available The aim of this work was to analyze, after a wildfire of moderate severity, the temporal fluctuations in water repellency and infiltration in a sandy loam soil under a mixed plantation of pine and eucalyptus and the comparison with an adjacent area not affected by the fire. In the burnt area and in a neighboring area not affected by the fire were collected during one year (1, 4, 6, 8 and 12 months after the fire 10 soil samples along a transect of 18 m at four depths: 0-2, 2-5, 5-10 and 10-20 cm. Soil water repellency was determined using the water drop penetration time test (WDPT test and the infiltration was measured with a mini-disc infiltrometer (pressure head h0 = -2 cm.The results show a temporal pattern of soil water repellency in the burnt and unburnt areas. Significant correlations between water repellency and soil moisture were observed, with higher correlation coefficients in the unburned area and in the surface soil layer.Soil water infiltration was significantly lower than would be expected by the coarse texture of the soil in both burnt and unburnt areas. Temporal fluctuations in unburnt soil infiltration seem to be clearly related to the transient nature of the soil water repellency, with no infiltration in samples extremely repellent. In the burned area, the soil infiltration showed much more variability and temporal fluctuations appear to be less dependent on the persistence of water repellency and more dependent on environmental conditions.The unburnt area show significant and negative correlations of soil water repellency with hydraulic conductivity and sorptivity and positive of these two parameters with soil moisture. These relationships were not observed in the burnt area. The temporal fluctuations of soil water repellency have an evident impact on soil infiltration and seem to be more influent than the effects of fire.

  10. Application Of Water Table Fluctuation Method To Quantify Spatial Groundwater Recharge Witidn The Southern Slope Of Merapi Volcano, Indonesia

    Directory of Open Access Journals (Sweden)

    Tjahyo Nugroho Adji

    2013-07-01

    that results in groundwater recharge characteristic. The volcanic slope unit (above 600 m as! has the lowest water table fluctuation indicates the resistant comportment to the annual rainfall. Ihis unit is characterized by the relatively high magnitude of recharge of approximately 4270 mm/year.

  11. Three-dimensional Fluorescence Spectral Characteristics of Different Molecular Weight Fractionations of Dissolved Organic Matter in the Water-level Fluctuation Zones of Three Gorges Reservoir Areas%三峡库区消落带水体 DOM 不同分子量组分三维荧光特征

    Institute of Scientific and Technical Information of China (English)

    陈雪霜; 江韬; 卢松; 魏世强; 王定勇; 闫金龙

    2016-01-01

    本研究利用超滤技术和三维荧光光谱,以三峡库区典型消落带水体溶解性有机质(DOM)不同分子量组分为对象,分析和讨论了不同分子量级分的组成差异和输入来源.结果表明,该区域 DOM 分子量分布情况较为分散,但胶体(Mr 1×103~0.22μm)和真溶态组分(Mr ﹤1×103)均对 DOC 总质量贡献相当.不同分子量级分中均存在 A、 C、 B、 T 峰,其相对含量分配均呈现出一致趋势,即真溶态(Mr ﹤1×103)﹥低分子量组分(Mr 1×103~10×103)﹥中分子量组分(Mr 10×103~30×103)﹥高分子量组分(Mr 30×103~0.22μm).另外,DOM 随超滤分子量等级降低,FI 和 BIX 值增加,“内源”输入特征增强;腐殖化程度降低(HIX 值下降).陆源输入主要影响高、中分子组分,而内源输入主要影响低分子及真溶态部分.同时,沿岸不同土地利用类型对水体 DOM 性质和组成影响明显.土地利用类型多样性、生态景观结构复杂程度越高,水体 DOM 不同分子量等级中各荧光组分也越复杂.%The study of the molecular weight (MW) fractions of dissolved organic matter (DOM) in aquatic environment is of interests because the size plays an important role in deciding the biogeochemical characteristics of DOM. Thus, using ultrafiltration ( UF) technique combined with three-dimensional fluorescence spectroscopy, DOM samples from four sampling sites in typical water-level fluctuation zones of Three Gorge Reservoir areas were selected to investigate the differences of properties and sources of different DOM MW fractions. The results showed that in these areas, the distribution of MW fractions was highly dispersive, but the approximately equal contributions from colloidal (Mr 1 × 103-0. 22 μm) and true dissolved fraction ( Mr ﹤ 1 × 103 ) to the total DOC concentration were found. Four fluorescence signals (humic-like A and C; protein-like B and T) were observed in all MW fractions including bulk DOM, which showed the

  12. Advanced methods for modeling water-levels and estimating drawdowns with SeriesSEE, an Excel add-in

    Science.gov (United States)

    Halford, Keith; Garcia, C. Amanda; Fenelon, Joe; Mirus, Benjamin B.

    2012-12-21

    Water-level modeling is used for multiple-well aquifer tests to reliably differentiate pumping responses from natural water-level changes in wells, or “environmental fluctuations.” Synthetic water levels are created during water-level modeling and represent the summation of multiple component fluctuations, including those caused by environmental forcing and pumping. Pumping signals are modeled by transforming step-wise pumping records into water-level changes by using superimposed Theis functions. Water-levels can be modeled robustly with this Theis-transform approach because environmental fluctuations and pumping signals are simulated simultaneously. Water-level modeling with Theis transforms has been implemented in the program SeriesSEE, which is a Microsoft® Excel add-in. Moving average, Theis, pneumatic-lag, and gamma functions transform time series of measured values into water-level model components in SeriesSEE. Earth tides and step transforms are additional computed water-level model components. Water-level models are calibrated by minimizing a sum-of-squares objective function where singular value decomposition and Tikhonov regularization stabilize results. Drawdown estimates from a water-level model are the summation of all Theis transforms minus residual differences between synthetic and measured water levels. The accuracy of drawdown estimates is limited primarily by noise in the data sets, not the Theis-transform approach. Drawdowns much smaller than environmental fluctuations have been detected across major fault structures, at distances of more than 1 mile from the pumping well, and with limited pre-pumping and recovery data at sites across the United States. In addition to water-level modeling, utilities exist in SeriesSEE for viewing, cleaning, manipulating, and analyzing time-series data.

  13. Mechanism analysis of landslide of a layered slope induced by drawdown of water level

    Institute of Scientific and Technical Information of China (English)

    ZHANG Junfeng; LI Zhengguo; QI Tao

    2005-01-01

    The frequent drawdown of water level of Yangtze River will greatly influence the stability of the widely existing slopes in the Three Gorges reservoir zone, especially those layered ones. Apart from the fluctuating speed of water level, the different geological materials will also play important roles in the failure of slopes. Thus, it must be first to study the mechanism of such a landslide caused by drawdown of water level.A new experimental setup is designed to study the performance of a layered slope under the drawdown of water level. The pattern of landslide of a layered slope induced by drawdown of water level has been explored by means of simulating experiments. The influence of fluctuating speed of water level on the stability of the layered slope is probed,especially the whole process of deformation and development of landslide of the slope versus time. The experimental results show that the slope is stable during the water level rising, and the sliding body occurs in the upper layer of the slope under a certain drawdown speed of water level. In the process of slope failure, some new small sliding body will develop on the main sliding body, and the result is that they speed up the disassembly of the whole slope.Based on the simulating experiment on landslide of a layered slope induced by drawdown of water level, the stress and displacement field of the slope are calculated.The seepage velocity, the pore water pressure, and the gradient of pore water head are also calculated for the whole process of drawdown of water level. The computing results are in good agreement with the experimental results. Accordingly, the mechanism of deformation and landslide of the layered slope induced by drawdown of water level is analyzed. It may provide basis for treating this kind of layered slopes in practical engineering.

  14. Fluctuating micro-heterogeneity in water-tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies

    Science.gov (United States)

    Banerjee, Saikat; Furtado, Jonathan; Bagchi, Biman

    2014-05-01

    Water-tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with xTBA ≈ 0.03-0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at xTBA ≈ 0.05. We note that "islands" of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, xTBA ≈ 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level.

  15. Fluctuating micro-heterogeneity in water-tert-butyl alcohol mixtures and lambda-type divergence of the mean cluster size with phase transition-like multiple anomalies.

    Science.gov (United States)

    Banerjee, Saikat; Furtado, Jonathan; Bagchi, Biman

    2014-05-21

    Water-tert-butyl alcohol (TBA) binary mixture exhibits a large number of thermodynamic and dynamic anomalies. These anomalies are observed at surprisingly low TBA mole fraction, with x(TBA) ≈ 0.03-0.07. We demonstrate here that the origin of the anomalies lies in the local structural changes that occur due to self-aggregation of TBA molecules. We observe a percolation transition of the TBA molecules at x(TBA) ≈ 0.05. We note that "islands" of TBA clusters form even below this mole fraction, while a large spanning cluster emerges above that mole fraction. At this percolation threshold, we observe a lambda-type divergence in the fluctuation of the size of the largest TBA cluster, reminiscent of a critical point. Alongside, the structure of water is also perturbed, albeit weakly, by the aggregation of TBA molecules. There is a monotonic decrease in the tetrahedral order parameter of water, while the dipole moment correlation shows a weak nonlinearity. Interestingly, water molecules themselves exhibit a reverse percolation transition at higher TBA concentration, x(TBA) ≈ 0.45, where large spanning water clusters now break-up into small clusters. This is accompanied by significant divergence of the fluctuations in the size of largest water cluster. This second transition gives rise to another set of anomalies around. Both the percolation transitions can be regarded as manifestations of Janus effect at small molecular level. PMID:24852545

  16. Large-scale fluctuations in Precambrian atmospheric and oceanic oxygen levels from the record of U in shales

    Science.gov (United States)

    Partin, C. A.; Bekker, A.; Planavsky, N. J.; Scott, C. T.; Gill, B. C.; Li, C.; Podkovyrov, V.; Maslov, A.; Konhauser, K. O.; Lalonde, S. V.; Love, G. D.; Poulton, S. W.; Lyons, T. W.

    2013-05-01

    The atmosphere-ocean system experienced a progressive change from anoxic to more oxidizing conditions through time. This oxidation is traditionally envisaged to have occurred as two stepwise increases in atmospheric oxygen at the beginning and end of the Proterozoic Eon. Here, we present a study of the redox-sensitive element, uranium, in organic-rich shales to track the history of Earth's surface oxidation at an unprecedented temporal resolution. Fluctuations in the degree of uranium enrichment in organic-rich shales suggest that the initial rise of atmospheric oxygen ~2.4 billion yr ago was followed by a decline to less oxidizing conditions during the mid-Proterozoic. This redox state persisted for almost 1 billion yr, ending with a second oxygenation event in the latest Neoproterozoic. The U record tracks major fluctuations in surface oxygen level and challenges conventional models that suggest the Earth underwent a unidirectional rise in atmospheric oxygen during the Precambrian.

  17. Individual fluctuations in toxin levels affect breeding site fidelity in a chemically defended amphibian.

    Science.gov (United States)

    Bucciarelli, Gary M; Green, David B; Shaffer, H Bradley; Kats, Lee B

    2016-05-25

    Behaviours that influence habitat selection strongly determine species movement patterns. One component of animal behaviour that largely influences movement patterns and habitat choice is site fidelity. California newts (family Salamandridae) demonstrate remarkable site fidelity, typically homing to the same pool of a stream each breeding season. Individuals often occupy a specific pool throughout the breeding season, but some males shift among breeding pools, altering their set of potential mates, competitors, and predators. In this study, we measured dermal concentrations of the chemical defence compound tetrodotoxin (TTX) in recaptured male California newts (Taricha torosa) over five breeding seasons to evaluate whether relative TTX concentrations are associated with breeding site fidelity in the field. Our five years of field sampling indicates that TTX concentrations of individuals and group means fluctuate tremendously, implying that TTX is not a stable phenotypic trait. Despite such fluctuations, we found that an individual's relative TTX concentration explains fidelity to a breeding pool and suggests that newts may be able to assess both their own concentrations of TTX and that of conspecifics to make decisions about remaining in or abandoning a breeding pool. These results provide us a novel dimension to chemical defence phenotypes in nature and their ecological consequences, potentially requiring a re-evaluation of the coevolutionary dynamics of predation pressure on toxin-laden organisms. PMID:27194704

  18. Water Level Detection Using Synthetic Aperture Radar Imagery

    International Nuclear Information System (INIS)

    inspection planning), object detection (verification of declared activities, or detection of undeclared activities), and detection of water level fluctuation (which may be linked to a clandestine power generation during a period where optical sensors are not effective, e.g. at night or during adverse weather conditions). Additional analysis of RADARSAT-1 data, supportable by ground truth information and IKONOS imagery, is being carried out and further results are expected to be available soon. Large steep walled or terraced reservoirs, as in the case of JEB Pit TMF would require a different analysis technique. Scoping work indicated that it would be possible to deduce the water level by measuring the wall height using 'radar shadow', in a manner similar to the exploitation of shadows in optical images

  19. Study on temperature fluctuation phenomena in pressurizer spray pipe of pressurized water reactor

    International Nuclear Information System (INIS)

    Damage of a pressurizer spray piping in a PWR plant is potentially considered from a safety point of views. Gas-liquid interface is formed in the pressurizer spray pipe of the PWR under a rated power operating condition. Temperature fluctuation may occur if the interface may move periodically. Measurement of inner wall and fluid temperature in the test section simulating the real pressurizer spray pipe was conducted to study mechanism of the temperature fluctuation phenomena. The temperature fluctuations were observed. Visualization experiment was conducted to understand the flow phenomena. It was estimated that Kelvin-Helmholtz instability occurred in the liquid layer in a horizontal pipe in the spray piping. (author)

  20. Entanglement dynamics for uniformly accelerated two-level atoms coupled with electromagnetic vacuum fluctuations

    CERN Document Server

    Yang, Yiquan; Yu, Hongwei

    2016-01-01

    We investigate the entanglement dynamics of two uniformly accelerated atoms with the same acceleration perpendicular to their separation. The two-atom system is treated as an open system coupled with fluctuating electromagnetic fields in the Minkowski vacuum, and in the Born-Markov approximation the master equation that describes the completely positive time evolution of the two-atom system is derived. In particular, we investigate the phenomena of entanglement degradation, generation, revival and enhancement. As opposed to the scalar-field case, the entanglement dynamics is crucially dependent on the polarization directions of the atoms. For the two-atom system with certain acceleration and separation, the polarization directions of the atoms may determine whether entanglement generation, revival or enhancement happens, while for entanglement degradation, they affect the decay rate of entanglement. A comparison between the entanglement evolution of accelerated atoms and that of static ones immersed in a ther...

  1. Discussion on sea level fluctuations along the Adriatic coasts coupling to climate indices forced by solar activity: Insights into the future of Venice

    Science.gov (United States)

    Zanchettin, Davide; Traverso, Pietro; Tomasino, Mario

    2006-04-01

    The North Atlantic Oscillation (NAO), which is a dominant circulation pattern in Northern Hemisphere winter, is known to affect sea-level variability in the Mediterranean Sea mainly through the hydrostatic response of water masses to pressure anomalies and changes in evaporation/precipitation budgets. In this study the influence of the NAO on sea levels along the Adriatic coasts is re-assessed in the attempt to uncover the potential causes of the observed high sensitivity of the northern basin to NAO fluctuations. The investigation is focused on the role of the NAO as forcing factor of the winds blowing in the area and of the freshwaters input from the Po River, both of which influence the hydrodynamics of the Northern Adriatic. In addition, some insights into the future of Venice are discussed on the basis of the hypothesis that NAO phases are modulated by the varying solar activity through the intensity of the Earth's geomagnetic activity.

  2. Hydro static water level systems at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Volk, J.T.; Guerra, J.A.; Hansen, S.U.; Kiper, T.E.; Jostlein, H.; Shiltsev, V.; Chupyra, A.; Kondaurov, M.; Singatulin, S.

    2006-09-01

    Several Hydrostatic Water Leveling systems (HLS) are in use at Fermilab. Three systems are used to monitor quadrupoles in the Tevatron and two systems are used to monitor ground motion for potential sites for the International Linear Collider (ILC). All systems use capacitive sensors to determine the water level of water in a pool. These pools are connected with tubing so that relative vertical shifts between sensors can be determined. There are low beta quadrupoles at the B0 and D0 interaction regions of Tevatron accelerator. These quadrupoles use BINP designed and built sensors and have a resolution of 1 micron. All regular lattice superconducting quadrupoles (a total of 204) in the Tevatron use a Fermilab designed system and have a resolution of 6 microns. Data on quadrupole motion due to quenches, changes in temperature will be presented. In addition data for ground motion for ILC studies caused by natural and cultural factors will be presented.

  3. Stratigraphic analysis of lake level fluctuations in Lake Ohrid: an integration of high resolution hydro-acoustic data and sediment cores

    OpenAIRE

    Lindhorst, K.; H. Vogel; S. Krastel; Wagner, B.; Hilgers, A.; Zander, A.; Schwenk, T.; Wessels, M.; Daut, G.

    2010-01-01

    Ancient Lake Ohrid is a steep sided, oligotrophic, karst lake of likely Pliocene age and often referred to as a hotspot of endemic biodiversity. This study aims on tracing significant lake level fluctuations at Lake Ohrid using high-resolution acoustic data in combination with lithological, geochemical, and chronological information from two sediment cores recovered from sub-aquatic terrace levels at ca. 32 and 55 m. According to our data, significant lake level fluctuations with prominent lo...

  4. A technique for estimating ground-water levels at sites in Rhode Island from observation-well data

    Science.gov (United States)

    Socolow, Roy S.; Frimpter, Michael H.; Turtora, Michael; Bell, Richard W.

    1994-01-01

    Estimates of future high, median, and low ground- water levels are needed for engineering and architectural design decisions and for appropriate selection of land uses. For example, the failure of individual underground sewage-disposal systems due to high ground-water levels can be prevented if accurate water-level estimates are available. Estimates of extreme or average conditions are needed because short duration preconstruction obser- vations are unlikely to be adequately represen- tative. Water-level records for 40 U.S. Geological Survey observation wells in Rhode Island were used to describe and interpret water-level fluctuations. The maximum annual range of water levels average about 6 feet in sand and gravel and 11 feet in till. These data were used to develop equations for estimating future high, median, and low water levels on the basis of any one measurement at a site and records of water levels at observation wells used as indexes. The estimating technique relies on several assumptions about temporal and spatial variations: (1) Water levels will vary in the future as they have in the past, (2) Water levels fluctuate seasonally (3) Ground-water fluctuations are dependent on site geology, and (4) Water levels throughout Rhode Island are subject to similar precipitation and climate. Comparison of 6,697 estimates of high, median, and low water levels (depth to water level exceeded 95, 50, and 5 percent of the time, respectively) with the actual measured levels exceeded 95, 50, and 5 percent of the time at 14 sites unaffected by pumping and unknown reasons, yielded mean squared errors ranging from 0.34 to 1.53 square feet, 0.30 to 1.22 square feet, and 0.32 to 2.55 square feet, respectively. (USGS)

  5. Use of inexpensive pressure transducers for measuring water levels in wells

    Science.gov (United States)

    Keeland, B.D.; Dowd, J.F.; Hardegree, W.S.

    1997-01-01

    Frequent measurement of below ground water levels at multiple locations is an important component of many wetland ecosystem studies. These measurements, however, are usually time consuming, labor intensive, and expensive. This paper describes a water-level sensor that is inexpensive and easy to construct. The sensor is placed below the expected low water level in a shallow well and, when connected to a datalogger, uses a pressure transducer to detect groundwater or surface water elevations. Details of pressure transducer theory, sensor construction, calibration, and examples of field installations are presented. Although the transducers must be individually calibrated, the sensors have a linear response to changing water levels (r2 ??? .999). Measurement errors resulting from temperature fluctuations are shown to be about 4 cm over a 35??C temperature range, but are minimal when the sensors are installed in groundwater wells where temperatures are less variable. Greater accuracy may be obtained by incorporating water temperature data into the initial calibration (0.14 cm error over a 35??C temperature range). Examples of the utility of these sensors in studies of groundwater/surface water interactions and the effects of water level fluctuations on tree growth are provided. ?? 1997 Kluwer Academic Publishers.

  6. Fluctuations of Phytoplankton Community in the Coastal Waters of Caspian Sea in 2006

    Directory of Open Access Journals (Sweden)

    Siamak Bagheri

    2011-01-01

    Full Text Available Problem statement: The Caspian Sea ecosystem has been suffered with many problems since 1980s. Aanthropogenic pollution from heavy metals, hydrocarbons, pesticides, changes in the quantity of nutrient inputs by rivers, are significant threats to biodiversity and biological resources such as plankton structure in the Caspian Sea. According to the significant of phytoplankton community in marine system. The state of the fluctuations of phytoplankton communities of the southwestern Caspian Sea was investigated and compared with the findings of before 2006. Approach: Phytoplankton abundance and species composition of the Caspian Sea were evaluated by using samples collected at 12 stations along three transects. Samplings were conducted seasonal in 2006 at 5, 10, 20 and 50 m depth were fixed for each transect in the southwestern Caspian Sea. Results: A total of 39 species phytoplankton species were distinguished during 2006, the annual phytoplankton abundance were calculated as 57, 300±15,550 cells.l-1, which ranged from 89, 250±35, 062 cells.l-1 in September to 16, 200±6,664 cells.l-1 in February. The diatoms formed more than half of the total abundance (61% while cyanophytes were the second important group in view of contribution to total phytoplankton (26% in 2006. The study showed that diatoms Thalassionema nitzschioides, Cyclotella meneghiniana and cyanophyte Osillatoria sp. numerically dominated in this area. Conclusion: The study revealed that diatoms were higher than other groups of phytoplankton in 2006. The hydrology variation, increased fresh water inflow via rivers and a rise in nutrients concentrations have played important roles in blooming of phytoplankton species, e.g., the diatoms in this study, which is also known from other marines. Similar studies on determination of the effects of environmental degradation on phytoplankton and hydrological processes should be taken into account in near future.

  7. Analysis and improvements of module incidental interference faults of water level control system pressurize NPP

    International Nuclear Information System (INIS)

    In Daya Bay nuclear power plant, there have been many times that the module used to value the water level outputs a small pulse interference when the pressurizer water level control system is in operation, and the interference exists only in analog storage operation module, which can directly impact the control of the water level of the pressurizer, causing the water level fluctuations and adversely affecting the safe operation of the reactor. This paper analyzes the module incidental interference faults of the water level control system of the NPP pressurizer from the point view of the system control and design of module hardware, and finds out the reasons by the system simulation experiment and power supply circuit test. It is suggested to further improve on the design of hardware loops, add more inductance and capacity to eliminate the interference. (authors)

  8. Climate-driven changes in water level

    DEFF Research Database (Denmark)

    Hansen, Rikke Bjerring; Olsen, Jesper; Jeppesen, Erik;

    2013-01-01

    similar to 150 years before the onset of the 8.2-ka cooling event registered in Greenland ice cores, but was synchronous with hydrologic change in the North American Lake Agassiz drainage. The lake level decrease was accompanied by a higher accumulation rate of inorganic matter and lower accumulation...... rates of cladoceran subfossils and algal pigments, possibly due to increased turbidity and reduced nutrient input during this drier period. Pigment analysis also showed added importance of diatoms and cryptophytes during this climate anomaly, while cyanobacteria became more important when the water...... level rose. Moreover, Nymphaeaceae trichosclereids were abundant during the period of algal enrichment. Cladoceran taxa associated with floating leaved plants or benthic habitats responded in a complex way to changes in water level, but the cladoceran assemblages generally reflected deep lake conditions...

  9. Persistence of Late Carboniferous tropical vegetation during glacially driven climatic and sea-level fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Di Michele, W.A.; Pfefferkorn, H.; Phillips, T.L. [Smithsonian Institution, Washington, DC (United States). Dept. of Paleobiology

    1996-10-01

    The Late Carboniferous glaciation reached its peak during the latter part of the Westphalian. In the tropical Illinois basin this was the time of deposition of the Carbondale and lower Modesto Formations, characterized by the cyclic repetition of major coal deposits, black shales, limestone, gray shales and sandstones. These lithological changes evidence repeated major fluctuations in climate and sealevel. Floras from coals, known from coal balls and palynology, characteristically were composed of three major plant communities: the wettest sites were dominated by monocarpic lycopsids, intermediate sites were dominated by polycarpic lycopsids, and areas subject to fires and intermittent flooding were dominated by medullosans and the small lycopsid Paralycopodites. Clastic-substrate environments were dominated by ferns and pteridosperms and conform to a single biozone, indicating their compositional unit and distinctness from earlier and later assemblages. The composition of lowland floras is poorly known from times between the deposition of coals and associated terrestrial rocks, intervals during which most of the lowlands were flooded and marine rocks were being deposited. Consequently, the temporally intermittent recurrence of lowland floras despite repeated, widespread environmental disruption may be explained either by vegetational persistence and migration of floras, or repeated disruption and reassembly. Several lines of evidence suggest persistence as a likely explanation.

  10. Detecting drawdowns masked by environmental stresses with water-level models

    Science.gov (United States)

    Garcia, C.A.; Halford, K.J.; Fenelon, J.M.

    2013-01-01

    Detecting and quantifying small drawdown at observation wells distant from the pumping well greatly expands the characterized aquifer volume. However, this detection is often obscured by water level fluctuations such as barometric and tidal effects. A reliable analytical approach for distinguishing drawdown from nonpumping water-level fluctuations is presented and tested here. Drawdown is distinguished by analytically simulating all pumping and nonpumping water-level stresses simultaneously during the period of record. Pumping signals are generated with Theis models, where the pumping schedule is translated into water-level change with the Theis solution. This approach closely matched drawdowns simulated with a complex three-dimensional, hypothetical model and reasonably estimated drawdowns from an aquifer test conducted in a complex hydrogeologic system. Pumping-induced changes generated with a numerical model and analytical Theis model agreed (RMS as low as 0.007 m) in cases where pumping signals traveled more than 1 km across confining units and fault structures. Maximum drawdowns of about 0.05 m were analytically estimated from field investigations where environmental fluctuations approached 0.2 m during the analysis period.

  11. Ecosystem health evaluation system of the water-fluctuating zone in the Three Gorges Area

    Institute of Scientific and Technical Information of China (English)

    WANG Li-ao; YUAN Hui; ZHANG Yan-hui; HU Gang

    2004-01-01

    This paper discribes the definition of ecosystem health for the water-level flutuation zone of the Three Gorges Region and puts forward an evaluation system involving indicators in three groups: 1) structural indicators comprise slope, biodiversity,environmental capacity, stability, restoration ability and damage situation; 2) functional indicators including probability of geological hazard, erosion rate, habitat rate, land use intension and days of tourist season; 3) environmental indicatiors made up of population quality, potential intension of human, ground water quality, ambient air quality, wastewater treatment rate, pesticide use rate, fertilizer use rate, environmental management and public participation. In the design of the system, the subject zone is regarded as the type similar to wetland and the impacts of human activities on the zone are attached great importance to.

  12. Relative lake level fluctuations and their influence on productivity and resilience in tropical lakes and reservoirs

    NARCIS (Netherlands)

    Kolding, J.; Zwieten, van P.A.M.

    2012-01-01

    Lakes and reservoirs are traditionally characterised from static morphological or chemical parameters such as depth and dissolved solids, while the dynamic impact of shifting water supplies has received little attention. There is increasing evidence, however, that the hydrodynamic regime in tropical

  13. Has sea level fluctuations modulated human settlements in Gulf of Khambhat (Cambay)?

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Hashimi, N.H.

    elements with holes and studs, pot shreds, beads, fossil bones etc., which provide significant evidence of human activity in the area. A detailed examination of the area has revealed riverine conglomerate at water depth of 30-40 m between 20 and 40 km west...

  14. GNSS-Reflectometry based water level monitoring

    Science.gov (United States)

    Beckheinrich, Jamila; Schön, Steffen; Beyerle, Georg; Apel, Heiko; Semmling, Maximilian; Wickert, Jens

    2013-04-01

    Due to climate changing conditions severe changes in the Mekong delta in Vietnam have been recorded in the last years. The goal of the German Vietnamese WISDOM (Water-related Information system for the Sustainable Development Of the Mekong Delta) project is to build an information system to support and assist the decision makers, planners and authorities for an optimized water and land management. One of WISDOM's tasks is the flood monitoring of the Mekong delta. Earth reflected L-band signals from the Global Navigation Satellite System show a high reflectivity on water and ice surfaces or on wet soil so that GNSS-Reflectometry (GNSS-R) could contribute to monitor the water level in the main streams of the Mekong delta complementary to already existing monitoring networks. In principle, two different GNSS-R methods exist: the code- and the phase-based one. As the latter being more accurate, a new generation of GORS (GNSS Occultation, Reflectometry and Scatterometry) JAVAD DELTA GNSS receiver has been developed with the aim to extract precise phase observations. In a two week lasting measurement campaign, the receiver has been tested and several reflection events at the 150-200 m wide Can Tho river in Vietnam have been recorded. To analyze the geometrical impact on the quantity and quality of the reflection traces two different antennas height were tested. To track separately the direct and the reflected signal, two antennas were used. To derive an average height of the water level, for a 15 min observation interval, a phase model has been developed. Combined with the coherent observations, the minimum slope has been calculated based on the Least- Squares method. As cycle slips and outliers will impair the results, a preprocessing of the data has been performed. A cycle slip detection strategy that allows for automatic detection, identification and correction is proposed. To identify outliers, the data snooping method developed by Baarda 1968 is used. In this

  15. Information Entropy. and Squeezing of Quantum Fluctuations in a Two-Level Atom

    Institute of Scientific and Technical Information of China (English)

    FANG Mao-Fa; ZHOU Peng; S. Swain

    2000-01-01

    We study the atomic squeezing in the language of the quantum information theory. A rigorous entropy uncertainty relation which suits for characterizing the squeezing of a two-level atoms is obtained, and a general definition of information entropy squeezing in the two-level atoms is given. The information entropy squeezing of two-level atoms interacting with a single-mode quantum field is examined. Our results show that the information entropy is a superior measure of the quantum uncertainty of atomic observable, also is a remarkable good precision measure of atomic squeezing. When the population difference of two-level atom is zero, the definition of atomic squeezing based on the Heisenberg uncertainty relation is trivial, while the definition of information entropy squeezing of the atom based on the entropy uncertainty relation is valid and can provide full information on the atomic squeezing in any cases.

  16. Investigation of wall temperature fluctuations by visualization tests for steam-water two-phase flow in the pressurizer spray piping

    International Nuclear Information System (INIS)

    In a PWR plant, a steam-water two phase flow may possibly exist in the pressurizer spray pipe under a rated power operating condition since the flow rate of the spray water is not sufficient to fill the horizontal section of the pipe completely. Under such thermally stratified two phase flow conditions, the initiation of high cycle fatigue cracks is suspected to occur due to cyclic thermal stress fluctuations caused by oscillations of the water surface, which cannot be detected by the measurement of temperature on outer surface of the pipe. In order to clarify the flow and thermal conditions in the pressurizer spray pipe and assess their impact on the pipe structure, an experiment was conducted for a steam-water flow at a low flow rate using a mock-up pressurizer spray pipe. By measuring inner wall temperature fluctuations, continuous temperature fluctuations, which were around 0.2 times of the steam water temperature difference in the maximum range, were observed at the inclined section where the water surface contacted the pipe wall. Then, we investigated the causes of the fluctuations by visualization tests. As a result of the experiment, it seemed that wall temperature fluctuations were not caused by waves on the water surface, but were caused by liquid temperature fluctuations a layer below the steam-water interface. The influence of a small amount of non-condensable gas dissolved in the reactor coolant on the wall temperature fluctuations was investigated by injecting air into the experimental loop. The liquid temperature fluctuations in the layer which caused wall temperature fluctuations were attenuated after air was injected. (author)

  17. Cerebrospinal Fluid Hypocretin-1 (Orexin-A Level Fluctuates with Season and Correlates with Day Length.

    Directory of Open Access Journals (Sweden)

    Kim Boddum

    Full Text Available The hypocretin/orexin neuropeptides (hcrt are key players in the control of sleep and wakefulness evidenced by the fact that lack of hcrt leads to the sleep disorder Narcolepsy Type 1. Sleep disturbances are common in mood disorders, and hcrt has been suggested to be poorly regulated in depressed subjects. To study seasonal variation in hcrt levels, we obtained data on hcrt-1 levels in the cerebrospinal fluid (CSF from 227 human individuals evaluated for central hypersomnias at a Danish sleep center. The samples were taken over a 4 year timespan, and obtained in the morning hours, thus avoiding impact of the diurnal hcrt variation. Hcrt-1 concentration was determined in a standardized radioimmunoassay. Using biometric data and sleep parameters, a multivariate regression analysis was performed. We found that the average monthly CSF hcrt-1 levels varied significantly across the seasons following a sine wave with its peak in the summer (June-July. The amplitude was 19.9 pg hcrt/mL [12.8-26.9] corresponding to a 10.6% increase in midsummer compared to winter. Factors found to significantly predict the hcrt-1 values were day length, presence of snow, and proximity to the Christmas holiday season. The hcrt-1 values from January were much higher than predicted from the model, suggestive of additional factors influencing the CSF hcrt-1 levels such as social interaction. This study provides evidence that human CSF hcrt-1 levels vary with season, correlating with day length. This finding could have implications for the understanding of winter tiredness, fatigue, and seasonal affective disorder. This is the first time a seasonal variation of hcrt-1 levels has been shown, demonstrating that the hcrt system is, like other neurotransmitter systems, subjected to long term modulation.

  18. Relict faunal testimony for sea-level fluctuations off Myanmar (Burma)

    Digital Repository Service at National Institute of Oceanography (India)

    Panchang, R.; Nigam, R.; Raviprasad, G.V.; Rajagopalan, G.; Ray, D.K.; Hla, U Ko Yi

    the colonization of corals during different sea stands and thus would show different ages. PROPOSITION OF A REGIONAL SEA LEVEL CURVE So as to establish the depth to age relationship of these samples, specimens of the relict foraminiferal assemblage from seven...

  19. Decreasing residual aluminum level in drinking water

    Institute of Scientific and Technical Information of China (English)

    王志红; 崔福义

    2004-01-01

    The relativity of coagulant dosage, residual turbidity, temperature, pH etc. with residual aluminum concentration were investigated, and several important conclusions were achieved. Firstly, dosage of alum-coagulant or PAC1 influences residual aluminum concentration greatly. There is an optimal-dosage-to-aluminum, a bit less than the optimal-dosage-to-turbidity. Secondly, it proposes that decreasing residual aluminum concentration can be theoretically divided into two methods, either decreasing (even removing) the concentration of particulate aluminum component, or decreasing dissolved aluminum. In these tests there is an optimal value of residual turbidity of postprecipitation at 7.0 NTU. Thirdly, residual aluminum level will increase while water temperature goes higher. At the last, optimal pH value corresponds a minimum dissolved aluminum at a given turbidity. Data shows the optimal pH value decreases with water temperature's increasing.

  20. The effect of interaural-level-difference fluctuations on the externalization of sound

    DEFF Research Database (Denmark)

    Catic, Jasmina; Santurette, Sébastien; Buchholz, Jörg M.;

    2013-01-01

    Real-world sound sources are usually perceived as externalized and thus properly localized in both direction and distance. This is largely due to (1) the acoustic filtering by the head, torso, and pinna, resulting in modifications of the signal spectrum and thereby a frequency-dependent shaping of...... interaural cues and (2) interaural cues provided by the reverberation inside an enclosed space. This study first investigated the effect of room reverberation on the spectro-temporal behavior of interaural level differences (ILDs) by analyzing dummy-head recordings of speech played at different distances in...

  1. The effects of climatic fluctuations and extreme events on running water ecosystems

    OpenAIRE

    Woodward, Guy; Bonada, Núria; Lee. E. Brown; Russell G. DEATH; Durance, Isabelle; Gray, Clare; Hladyz, Sally; Ledger, Mark E.; Milner, Alexander M.; Ormerod, Steve J.; Thompson, Ross M.; Pawar, Samraat

    2016-01-01

    Most research on the effects of environmental change in freshwaters has focused on incremental changes in average conditions, rather than fluctuations or extreme events such as heatwaves, cold snaps, droughts, floods or wildfires, which may have even more profound consequences. Such events are commonly predicted to increase in frequency, intensity and duration with global climate change, with many systems being exposed to conditions with no recent historical precedent. We propose a mechanisti...

  2. Monitoring of heavy water flow in a 'cannelloni' spallation target through fluctuation analysis of measured temperatures

    International Nuclear Information System (INIS)

    A simple and reliable technique of heavy water flow rate monitoring in a 'cannelloni' spallation target is described in this paper. The Swiss Spallation Neutron Source (SINQ) is a large scale facility for matter scattering at Paul Scherrer Institute; neutrons are produced in the spallation target composed of a bundle of zircaloy rods filled with lead. A beam of high speed protons strikes the rods. Neutrons and a large amount of thermal power (up to 800 kW) are produced by spallation reaction. Cooling is essential for safe and proper work of the target. Redundancy of all the monitoring systems is considered beneficial for overall safety of the facility. The paper below introduces an alternative way for coolant (heavy water, D2O) flow monitoring by measurement of propagation of thermal transient fronts in the target. Several data processing methods are analyzed. The heavy water (D2O) circulates between the bundle of rods and a heat exchanger. The proton beam current is not fully stable - as a rule there are at least 4 – 6 beam trips occurring during one hour of the target operation. These proton beam trips lead to a rapid change in heat release in the target spallation zone and corresponding change in the cooling water temperature. Such temperature fluctuation front arise in the water flow from the target's spallation zone towards the heat exchanger. The target cooling loop is equipped with several thermocouples placed along the heavy water flow path; the thermocouples are connected to a data acquisition system, which records the signals. The thermocouples placed at different distances downstream the target spallation zone react one by one to the passage of a temperature fluctuation front. Thus the water flow rate can be calculated based on time difference between the moments this temperature front been detected at different time by sequently placed thermocouples. (author)

  3. Dynamics of a Landau–Zener non-dissipative system with fluctuating energy levels

    Energy Technology Data Exchange (ETDEWEB)

    Fai, L.C. [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang, Dschang (Cameroon); Diffo, J.T., E-mail: diffojaures@yahoo.com [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang, Dschang (Cameroon); Department of Physics, Higher Teachers’ Training College, The University of Maroua, Maroua (Cameroon); Ateuafack, M.E.; Tchoffo, M.; Fouokeng, G.C. [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang, Dschang (Cameroon)

    2014-12-01

    This paper considers a Landau–Zener (two-level) system influenced by a three-dimensional Gaussian and non-Gaussian coloured noise and finds a general form of the time dependent diabatic quantum bit (qubit) flip transition probabilities in the fast, intermediate and slow noise limits. The qubit flip probability is observed to mimic (for low-frequencies noise) that of the standard LZ problem. The qubit flip probability is also observed to be the measure of quantum coherence of states. The transition probability is observed to be tailored by non-Gaussian low-frequency noise and otherwise by Gaussian low-frequency coloured noise. Intermediate and fast noise limits are observed to alter the memory of the system in time and found to improve and control quantum information processing.

  4. Determination of heterogeneities in the hydraulic properties of a phreatic aquifer from tidal level fluctuations: a case in Argentina

    Science.gov (United States)

    Carol, Eleonora S.; Kruse, Eduardo E.; Pousa, Jorge L.; Roig, Alejandro R.

    2009-11-01

    A well-known analytical solution of Jacob (1950) for groundwater flow due to tidal-wave propagation, together with field measurements along a complete tidal cycle and geological data, were used to evaluate the heterogeneities in the hydraulic properties of a phreatic aquifer located next to the River Ajo in the coastal plain environment of the southern sector of the Samborombon Bay wetland, Argentina. From the analysis of water-table fluctuations in a set of monitoring wells located along a riverbank-normal transect, it was possible to quantify the piecewise spatial variations of the hydraulic diffusivity of the phreatic aquifer. The results show the strong lateral variations of the sedimentary environment due to the influence of the different transport and deposition agents that characterize the coastal plain. The known thickness of the phreatic aquifer and the estimated range of the specific yield allowed the hydraulic conductivity to be identified as the most influential factor. [Jacob CE (1950) Flow of ground water. In: Rouse H (ed) Engineering Hydraulics. Wiley, New York

  5. Analysis on the Characteristics of the Coseismic Response of Water Levels Recorded in Three Wells in Hainan,China to the Two Sumatra-Andaman Strong Earthquakes

    Institute of Scientific and Technical Information of China (English)

    Li Zhixiong; Gu Shenyi; Yuan Xiwen; Liu Wei; Ming Suihua; Yang Guang; Guo Nan

    2008-01-01

    The characteristics of seismic water level fluctuations of the two Sumatra-Andaman strong earthquakes with magnitude 8.7 and 8.5 on December 26,2004 and March 29,2005 recorded at Jiaji well,Qionghai,Hainan were analyzed,the features of the infrequent"step" changes of well water level after the two earthquakes were also analyzed and the mechanism of the"step change"of well water level was discussed.Then the high-sample-rate digital observation data of seismically-induced water level fluctuations of the Sumatra-Andaman strong earthquakes with magnitude 8.7 and 8.5 recorded at Nanbin well,Sanya and Tanniu well,Wenchang were analyzed.The results suggest that the dominant period of the seismic well water level fluctuation in all three wells was comparatively accordant,the amplitudes of seismic water level fluctuation of the same earthquake in different wells were clearly different,the time duration of seismic water level fluctuations of different earthquakes at the same well was also clearly different.

  6. Uranium redistribution due to water table fluctuations in sandy wetland mesocosms

    Energy Technology Data Exchange (ETDEWEB)

    Gilson, Emily R.; Huang, Shan; Koster van Groos, Paul G.; Scheckel, Kirk G.; Qafoku, Odeta; Peacock, Aaron D.; Kaplan, Daniel I.; Jaffe, Peter R.

    2015-10-20

    In order to better understand the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated wetland mesocosms planted with Scirpus acutus with low levels of uranyl acetate for 4 months before imposing a short drying and rewetting period. Concentrations of U in mesocosm effluent increased after drying and rewetting, but the cumulative amount of U released following the dry period constituted less than 1% of the total U immobilized in the soil during the 4 months prior. This low level of remobilization suggests, and XAS analyses confirm, that microbial reduction was not the primary means of U immobilization, as the U immobilized in mesocosms was primarily U(VI) rather than U(IV). Drying followed by re-wetting caused a redistribution of U downward in the soil profile and on to root surfaces. While the U on roots before drying was primarily associated with minerals, the U that relocated to the roots during drying and rewetting was bound diffusely to root surfaces. Results show that short periods of drought conditions in a wetland, which expose reduced sediments to air, may impact U distribution, but these conditions may not cause large releases of soil-bound U from planted wetlands to surface waters.

  7. Seasonal fluctuations in water repellency and infiltration in a sandy loam soil after a forest fire in Galicia (NW Spain)

    OpenAIRE

    M. Rodríguez-Alleres; M.E. Varela; Benito, E.

    2013-01-01

    The aim of this work was to analyze, after a wildfire of moderate severity, the temporal fluctuations in water repellency and infiltration in a sandy loam soil under a mixed plantation of pine and eucalyptus and the comparison with an adjacent area not affected by the fire. In the burnt area and in a neighboring area not affected by the fire were collected during one year (1, 4, 6, 8 and 12 months after the fire) 10 soil samples along a transect of 18 m at four depths: 0-2, 2-5, 5-10 and 10-2...

  8. A possible role of fluctuating clay-water systems in the production of ordered prebiotic oligomers

    Science.gov (United States)

    Lahav, N.; White, D. H.

    1980-01-01

    A model is proposed for the intermediate stages of prebiotic evolution, based on the characteristics of the adsorption and condensation of amino acids and nucleotides on the surface area of clay minerals in a fluctuating environment. Template replication and translation of adsorbed oligonucleotides and catalytic effects by peptide products on further condensation are proposed, due to specific properties of hypohydrous clay surfaces as well as the biomolecules themselves. Experimental evidence supports some of the proposed interactions, and all of them can be tested experimentally.

  9. Can the Gulf Stream induce coherent short-term fluctuations in sea level along the US East Coast? A modeling study

    Science.gov (United States)

    Ezer, Tal

    2016-02-01

    Much attention has been given in recent years to observations and models that show that variations in the transport of the Atlantic Meridional Overturning Circulation (AMOC) and in the Gulf Stream (GS) can contribute to interannual, decadal, and multi-decadal variations in coastal sea level (CSL) along the US East Coast. However, less is known about the impact of short-term (time scales of days to weeks) fluctuations in the GS and their impact on CSL anomalies. Some observations suggest that these anomalies can cause unpredictable minor tidal flooding in low-lying areas when the GS suddenly weakens. Can these short-term CSL variations be attributed to changes in the transport of the GS? An idealized numerical model of the GS has been set up to test this proposition. The regional model uses a 1/12° grid with a simplified coastline to eliminate impacts from estuaries and small-scale coastal features and thus isolate the GS impact. The GS in the model is driven by inflows/outflows, representing the Florida Current (FC), the Slope Current (SC), and the Sargasso Sea (SS) flows. Forcing the model with an oscillatory FC transport with a period of 2, 5, and 10 days produced coherent CSL variations from Florida to the Gulf of Maine with similar periods. However, when imposing variations in the transports of the SC or the SS, they induce CSL variations only north of Cape Hatteras. The suggested mechanism is that variations in GS transport produce variations in sea level gradient across the entire GS length and this large-scale signal is then transmitted into the shelf by the generation of coastal-trapped waves (CTW). In this idealized model, the CSL variations induced by variations of ˜10 Sv in the transport of the GS are found to resemble CSL variations induced by ˜5 m s-1 zonal wind fluctuations, though the mechanisms of wind-driven and GS-driven sea level are quite different. Better understanding of the relation between variations in offshore currents and CSL will help

  10. Drinking Water Maximum Contaminant Levels (MCLs)

    Data.gov (United States)

    U.S. Environmental Protection Agency — National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards...

  11. Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

    Directory of Open Access Journals (Sweden)

    S.A. Gomes

    2004-09-01

    Full Text Available the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH irrespective of the ionized calcium (sCa2+ levels. Blood samples were collected at baseline (0 min and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9 or hypercalcemic (N = 8. Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180' than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

  12. Response to an oral calcium load in nephrolithiasis patients with fluctuating parathyroid hormone and ionized calcium levels

    Directory of Open Access Journals (Sweden)

    Gomes S.A.

    2004-01-01

    Full Text Available the response to an oral calcium load test was assessed in 17 hypercalciuric nephrolithiasis patients who presented elevated parathyroid hormone (PTH irrespective of the ionized calcium (sCa2+ levels. Blood samples were collected at baseline (0 min and at 60 and 180 min after 1 g calcium load for serum PTH, total calcium, sCa2+, and 1.25(OH2D3 determinations. According to the sCa2+ level at baseline, patients were classified as normocalcemic (N = 9 or hypercalcemic (N = 8. Six healthy subjects were also evaluated as controls. Bone mineral density was reduced in 14/17 patients. In the normocalcemic group, mean PTH levels at 0, 60 and 180 min (95 ± 76, 56 ± 40, 57 ± 45 pg/ml, respectively did not differ from the hypercalcemic group (130 ± 75, 68 ± 35, 80 ± 33 pg/ml but were significantly higher compared to healthy subjects despite a similar elevation in sCa2+ after 60 and 180 min vs baseline in all 3 groups. Mean total calcium and 1.25(OH2D3 were similar in the 3 groups. Additionally, we observed that 5 of 9 normocalcemic patients presented a significantly higher concentration-time curve for serum PTH (AUC0',60',180' than the other 4 patients and the healthy subjects, suggesting a primary parathyroid dysfunction. These data suggest that the individual response to an oral calcium load test may be a valuable dynamic tool to disclose a subtle primary hyperparathyroidism in patients with high PTH and fluctuating sCa2+ levels, avoiding repeated measurements of both parameters.

  13. Testing of NAPL simulator to predict migration of a light nonaqueous phase liquid (LNAPL) under water table fluctuation in a sandy medium

    Institute of Scientific and Technical Information of China (English)

    周劲风; 李雁; 徐军

    2014-01-01

    Nanoqueous phase liquid (NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface, but the testing of its feasibility under water table fluctuation has received insufficient attention. The feature in a column test was tested through two cycles of water table fluctuation. The sandy medium in the column was initially saturated, and each cycle of water table fluctuation consisted of one water table falling and one rising, resulting in a drainage and an imbibition of the medium, respectively. It was found that the difference between the simulated and measured results in the first drainage of the column test was minor. However, with the propagation of the water table fluctuations, the simulation errors increased, and the simulation accuracy was not acceptable except for the first drainage in the two fluctuation cycles. The main reason was proved to be the estimation method of residual saturation used in this simulator. Also, based on the column tests, it was assumed that the resulting residual saturation from an incomplete imbibition process was a constant, with a value equal to that of the residual value resulting from the main imbibition process. The results obtained after modifying NAPL simulator with this assumption were found to be more accurate in the first cycle of water table fluctuation, but this accuracy decreased rapidly in the second one. It is concluded that NAPL simulator is not adequate in the case of LNAPL migration under water table fluctuation in sandy medium, unless a feasible assumption to estimate residual saturation is put forward.

  14. Evaluation of statistical properties of free-surface fluctuation on a high-speed water jet using laser refraction technique

    International Nuclear Information System (INIS)

    Free-surface fluctuation on a high-speed water jet has been evaluated using a laser beam refraction technique. This technique employs two pulse laser diodes and one high-speed optic detector. By detecting the two dimensional (2D) trajectory of laser beams refracted at free surface, the local streamwise slope-angle fluctuation at two measuring locations 1.27 mm apart on a jet free surface can be evaluated. The experiments are conducted for several locations along the jet center axis within the range of average velocity up to 10 m/s. The wave speed is evaluated from dominant time lag of cross-correlation coefficient for individual wave period, which is divided from time-series slope-angle data according to the zero-up-crossing method. The shape of waves is also calculated by integrating the free-surface slope angle. The wavelength and wave height are evaluated from the individual waveform. The steepness of free surface wave takes a maximum at a certain distance from nozzle exit for U ≤ 8 m/s. This suggests that the initial amplification of wave results in a wave breaking on the jet free surface for these velocity conditions. (author)

  15. Effects of Water Levels on Productivity of Canada Geese in the Northern Flathead Valley, Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Daniel

    1987-08-01

    The Fish and Wildlife Program of the Northwest Power Planning Council calls for wildlife mitigation at hydroelectric projects in the Columbia River System. Beginning April, 1984, the Bonneville Power Administration funded a study of the effects of the operation of Hungry Horse and Kerr Dams on the western Canada goose (Branta canadensis moffittii) inhabitating the Flathead Valley of northwest Montana. The study was conducted by personnel of the Montana Department of Fish, Wildlife and Parks (MDFWP), to: (1) identify the size and productivity of this population, (2) identify current habitat conditions and losses of nesting and brood-rearing areas, (3) describe the effects of water level fluctuations on nesting and brood-rearing, and (4) identify mitigation alternatives to offset these effects. Annual pair and nest surveys were used to document the location and fate of goose nests. The number of known nesting attempts varied from 44 in 1984 to 108 in 1985, to 136 in 1986 and 134 in 1987. Fifty-four percent of the annual meeting nesting effort took place on elevated sites which were secure from the flooding and dewatering effects of fluctuating water levels. An average of 15 nests were found on stumps in the remnant Flathead River delta, however, an area strongly influenced by the operation of Kerr Dam. Annual nest losses to flooding and predation attributable to fluctuations caused by the dam were recorded. 53 refs., 24 figs., 35 tabs.

  16. Wave-induced mass transport affects daily Escherichia coli fluctuations in nearshore water

    Science.gov (United States)

    Ge, Zhongfu; Whitman, Richard L.; Nevers, Meredith B.; Phanikumar, Mantha S.

    2012-01-01

    Characterization of diel variability of fecal indicator bacteria concentration in nearshore waters is of particular importance for development of water sampling standards and protection of public health. Significant nighttime increase in Escherichia coli (E. coli) concentration in beach water, previously observed at marine sites, has also been identified in summer 2000 from fixed locations in waist- and knee-deep waters at Chicago 63rd Street Beach, an embayed, tideless, freshwater beach with low currents at night (approximately 0.015 m s–1). A theoretical model using wave-induced mass transport velocity for advection was developed to assess the contribution of surface waves to the observed nighttime E. coli replenishment in the nearshore water. Using average wave conditions for the summer season of year 2000, the model predicted an amount of E. coli transported from water of intermediate depth, where sediment resuspension occurred intermittently, that would be sufficient to have elevated E. coli concentration in the surf and swash zones as observed. The nighttime replenishment of E. coli in the surf and swash zones revealed here is an important phase in the cycle of diel variations of E. coli concentration in nearshore water. According to previous findings in Ge et al. (Environ. Sci. Technol. 2010, 44, 6731–6737), enhanced current circulation in the embayment during the day tends to displace and deposit material offshore, which partially sets up the system by the early evening for a new period of nighttime onshore movement. This wave-induced mass transport effect, although facilitating a significant base supply of material shoreward, can be perturbed or significantly influenced by high currents (orders of magnitude larger than a typical wave-induced mass transport velocity), current-induced turbulence, and tidal forcing.

  17. Effects of water level regulation on littoral zone of lakes Konnivesi and Ruotsalainen

    International Nuclear Information System (INIS)

    Measures to develop an ecologically based regulation practice for the lakes Ruotsalainen and Konnivesi which belong to the Kymijoki watercourse, were undertaken in 1995, when the intermunicipal board for the Heinola health care centre and Myllykoski Oy proposed that the regulation licence should re-evaluated. The purpose of this study, which is part of the overall development project, was to assess the ecological impacts of regulation on the littoral zones of these lakes. More specifically, the study focussed on the changes in the ecology of the littoral zone due to the water level fluctuation. The littoral vegetation of lake Konnivesi reflects the improvement of water quality over the past fifteen years. The species indicative of eutrophication have mostly disappeared. The vegetation of the uppermost littoral zone has stabilised, and the effect of wave erosion is small Ice pressure on the bottom has hardly any impact on the plants sensitive to the ice scouring effect, because the ice-covered zone has actually been reduced in size consequent to the regulation. Owing to the small range of water level fluctuation during the open water period, the uppermost littoral zone remains very narrow, which restricts the spreading of especially helophytic vegetation. The narrow littoral zone impairs the development of the normal zonal biotope in many places and simultaneously prevents diverse increase of littoral biota. The aim of the ecological regulation practice proposed for Konnivesi is to ensure a water level favourable for pike spawning It is further proposed that the water level should decline by 25 cm during the open water period following the flood peak. This would help to widen the littoral zone suited to helophytic vegetation and to increase the vegetational diversity of especially gently sloping shores. (orig.) 12 refs

  18. Global gray water footprint and water pollution levels related to anthropogenic nitrogen loads to fresh water

    OpenAIRE

    Mesfin M Mekonnen; Hoekstra, Arjen Y

    2015-01-01

    This is the first global assessment of nitrogen-related water pollution in river basins with a specification of the pollution by economic sector, and by crop for the agricultural sector. At a spatial resolution of 5 by 5 arc minute, we estimate anthropogenic nitrogen (N) loads to freshwater, calculate the resultant gray water footprints (GWFs), and relate the GWFs per river basin to runoff to calculate the N-related water pollution level (WPL) per catchment. The accumulated global GWF related...

  19. A hydraulic model is compatible with rapid changes in leaf elongation under fluctuating evaporative demand and soil water status.

    Science.gov (United States)

    Caldeira, Cecilio F; Bosio, Mickael; Parent, Boris; Jeanguenin, Linda; Chaumont, François; Tardieu, François

    2014-04-01

    Plants are constantly facing rapid changes in evaporative demand and soil water content, which affect their water status and growth. In apparent contradiction to a hydraulic hypothesis, leaf elongation rate (LER) declined in the morning and recovered upon soil rehydration considerably quicker than transpiration rate and leaf water potential (typical half-times of 30 min versus 1-2 h). The morning decline of LER began at very low light and transpiration and closely followed the stomatal opening of leaves receiving direct light, which represent a small fraction of leaf area. A simulation model in maize (Zea mays) suggests that these findings are still compatible with a hydraulic hypothesis. The small water flux linked to stomatal aperture would be sufficient to decrease water potentials of the xylem and growing tissues, thereby causing a rapid decline of simulated LER, while the simulated water potential of mature tissues declines more slowly due to a high hydraulic capacitance. The model also captured growth patterns in the evening or upon soil rehydration. Changes in plant hydraulic conductance partly counteracted those of transpiration. Root hydraulic conductivity increased continuously in the morning, consistent with the transcript abundance of Zea maize Plasma Membrane Intrinsic Protein aquaporins. Transgenic lines underproducing abscisic acid, with lower hydraulic conductivity and higher stomatal conductance, had a LER declining more rapidly than wild-type plants. Whole-genome transcriptome and phosphoproteome analyses suggested that the hydraulic processes proposed here might be associated with other rapidly occurring mechanisms. Overall, the mechanisms and model presented here may be an essential component of drought tolerance in naturally fluctuating evaporative demand and soil moisture.

  20. Germination rates of Solanum sisymbriifolium: temperature response models, effects of temperature fluctuations and soil water potential

    NARCIS (Netherlands)

    Timmermans, B.G.H.; Vos, J.; Nieuwburg, van J.G.W.; Stomph, T.J.; Putten, van der P.E.L.

    2007-01-01

    Four temperature response models were compared describing the emergence rate of Solanum sisymbriifolium (L.) over a broad range of suboptimal temperatures and at different soil water potentials. In the laboratory, the effects were tested on germination rates at constant (9.1-21.8 degrees C) and diur

  1. Temperature Fluctuation, Low Salinity, Water Microflora: Risk Factors for WSSV Outbreaks in Penaeus monodon

    NARCIS (Netherlands)

    Tendencia Alapide, E.; Verreth, J.A.J.

    2011-01-01

    White spot syndrome virus (WSSV) has been devastating the shrimp industry for almost a decade. This study compares water parameters, alkalinity, and microflora in three ponds on a farm on Negros Island (Philippines) during two production cycles where WSSV infection resulted in an outbreak in 2006 bu

  2. Primary collector wall local temperature fluctuations in the area of water-steam phase boundary

    Energy Technology Data Exchange (ETDEWEB)

    Matal, O.; Klinga, J.; Simo, T. [Energovyzkum Ltd., Brno (Switzerland)

    1995-12-31

    A limited number of temperature sensors could be installed at the primary collector surface in the area of water - steam phase boundary. The surface temperatures as well WWER 440 steam generator process data were measured and stored for a long time and off-line evaluated. Selected results are presented in the paper. (orig.). 2 refs.

  3. Fluctuating water depths affect American alligator (Alligator mississippiensis) body condition in the Everglades, Florida, USA

    Science.gov (United States)

    Brandt, Laura A.; Beauchamp, Jeffrey S.; Jeffery, Brian M.; Cherkiss, Michael S.; Mazzotti, Frank J.

    2016-01-01

    Successful restoration of wetland ecosystems requires knowledge of wetland hydrologic patterns and an understanding of how those patterns affect wetland plant and animal populations.Within the Everglades, Florida, USA restoration, an applied science strategy including conceptual ecological models linking drivers to indicators is being used to organize current scientific understanding to support restoration efforts. A key driver of the ecosystem affecting the distribution and abundance of organisms is the timing, distribution, and volume of water flows that result in water depth patterns across the landscape. American alligators (Alligator mississippiensis) are one of the ecological indicators being used to assess Everglades restoration because they are a keystone species and integrate biological impacts of hydrological operations through all life stages. Alligator body condition (the relative fatness of an animal) is one of the metrics being used and targets have been set to allow us to track progress. We examined trends in alligator body condition using Fulton’s K over a 15 year period (2000–2014) at seven different wetland areas within the Everglades ecosystem, assessed patterns and trends relative to restoration targets, and related those trends to hydrologic variables. We developed a series of 17 a priori hypotheses that we tested with an information theoretic approach to identify which hydrologic factors affect alligator body condition. Alligator body condition was highest throughout the Everglades during the early 2000s and is approximately 5–10% lower now (2014). Values have varied by year, area, and hydrology. Body condition was positively correlated with range in water depth and fall water depth. Our top model was the “Current” model and included variables that describe current year hydrology (spring depth, fall depth, hydroperiod, range, interaction of range and fall depth, interaction of range and hydroperiod). Across all models, interaction

  4. Conformational fluctuations of a protein-DNA complex and the structure and ordering of water around it

    Science.gov (United States)

    Sinha, Sudipta Kumar; Bandyopadhyay, Sanjoy

    2011-12-01

    Protein-DNA binding is an important process responsible for the regulation of genetic activities in living organisms. The most crucial issue in this problem is how the protein recognizes the DNA and identifies its target base sequences. Water molecules present around the protein and DNA are also expected to play an important role in mediating the recognition process and controlling the structure of the complex. We have performed atomistic molecular dynamics simulations of an aqueous solution of the protein-DNA complex formed between the DNA binding domain of human TRF1 protein and a telomeric DNA. The conformational fluctuations of the protein and DNA and the microscopic structure and ordering of water around them in the complex have been explored. In agreement with experimental studies, the calculations reveal conformational immobilization of the terminal segments of the protein on complexation. Importantly, it is discovered that both structural adaptations of the protein and DNA, and the subsequent correlation between them to bind, contribute to the net entropy loss associated with the complex formation. Further, it is found that water molecules around the DNA are more structured with significantly higher density and ordering than that around the protein in the complex.

  5. Level densities of 29Si as determined from fluctuations of 28Si(n,p) and 28Si(n,α) cross sections

    International Nuclear Information System (INIS)

    Partial cross sections have been measured at LAMPF/WNR for neutron-induced charged particle reactions on 28Si. Data were obtained using a open-quotes whiteclose quotes neutron source for neutrons up to 30 MeV over a 90-meter flight path. The authors have determined excitation functions for proton and alpha emission for the most energetic charged particle groups. Fluctuations in the cross sections were observed in the neutron energy range below 15 MeV. They have undertaken a detailed study of these fluctuations via an Ericson analysis. This analysis has provided them with level width and level density information for the 29Si compound nucleus. Values for level widths and level densities will be compared with previous measurements including those obtained from total cross sections

  6. NOAA NOS SOS, EXPERIMENTAL - Water Level

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have water surface height above a reference datum. *These services are for...

  7. Estimation of groundwater recharge of shallow aquifer on humid environment in Yaounde, Cameroon using hybrid water-fluctuation and hydrochemistry methods

    OpenAIRE

    Takounjou, A. F.; Ngoupayou, J. R. N.; Riotte, Jean; Takem, G. E.; Mafany, G.; Maréchal, J. C.; Ekodeck, G. E.

    2011-01-01

    A study of environmental chloride and groundwater balance has been carried out in order to estimate their relative value for measuring average groundwater recharge under a humid climatic environment with a relatively shallow water table. The hybrid water fluctuation method allowed the split of the hydrologic year into two seasons of recharge (wet season) and no recharge (dry season) to appraise specific yield during the dry season and, second, to estimate recharge from the water table rise du...

  8. Water-vapor climate feedback inferred from climate fluctuations, 2003-2008

    Science.gov (United States)

    Dessler, A. E.; Zhang, Z.; Yang, P.

    2008-10-01

    Between 2003 and 2008, the global-average surface temperature of the Earth varied by 0.6°C. We analyze here the response of tropospheric water vapor to these variations. Height-resolved measurements of specific humidity (q) and relative humidity (RH) are obtained from NASA's satellite-borne Atmospheric Infrared Sounder (AIRS). Over most of the troposphere, q increased with increasing global-average surface temperature, although some regions showed the opposite response. RH increased in some regions and decreased in others, with the global average remaining nearly constant at most altitudes. The water-vapor feedback implied by these observations is strongly positive, with an average magnitude of λ q = 2.04 W/m2/K, similar to that simulated by climate models. The magnitude is similar to that obtained if the atmosphere maintained constant RH everywhere.

  9. Numerical Study on the Characteristics of Pressure Fluctuations in an Axial-Flow Water Pump

    OpenAIRE

    Zhi-Jun Shuai; Wan-You Li; Xiang-Yuan Zhang; Chen-Xing Jiang; Feng-Chen Li

    2014-01-01

    Flow induced vibration due to the dynamics of rotor-stator interaction in an axial-flow pump is one of the most damaging vibration sources to the pump components, attached pipelines, and equipment. Three-dimensional unsteady numerical simulations were conducted on the complex turbulent flow field in an axial-flow water pump, in order to investigate the flow induced vibration problem. The shear stress transport (SST) k-ω model was employed in the numerical simulations. The fast Fourier transfo...

  10. Uranium Redistribution Due to Water Table Fluctuations in Sandy Wetland Mesocosms

    Science.gov (United States)

    To understand better the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated wetland mesocosms planted with Scirpus acutus with low levels of uranyl acetate for 4 months before imposing...

  11. Lake level fluctuations and catchment dynamics at Lake Ohrid (Macedonia, Albania) during MIS6 and MIS5

    Science.gov (United States)

    Francke, Alexander; Wagner, Bernd; Just, Janna; Sadori, Laura; Masi, Alessia; Vogel, Hendrik; Lindhorst, Katja; Krastel, Sebastian; Dosseto, Anthony; Rothacker, Leo; Leicher, Niklas; Gromig, Raphael

    2016-04-01

    Lake Ohrid, presumably the oldest lake of Europe located at the border of Macedonia and Albania, is about 30 km long, 15 km wide, and up to 290 m deep. In 2013, an ICDP deep drilling campaign was carried out under the umbrella of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. At the main drill site (DEEP) in the central part of Lake Ohrid, the uppermost 568 m from a total sediment fill of ca. 700 m were recovered. Initial data from core catcher material indicate that the sediment sequence covers more than 1.2 million years. An age model, which is based on 11 tephrostratigragphic tie points and on tuning of biogeochemical proxy data versus orbital parameters reveals that that the upper 247 m of the DEEP site sequence cover the time period between 637 ka (MIS16) and the present. Inhere, we present sedimentological, (bio-)geochemical, environmental magnetic, and pollen data for the time period between MIS6 (191 ka) and MIS5 (71 ka). The data imply that MIS6 was one of the most severe glacial periods, while MIS5 was likely one of the more pronounced interglacial during the past 637 kyrs. The repercussions of these high amplitude climatic and environmental variations during this period are recorded in the sedimentological archive of Lake Ohrid. Previous studies based on hydro-acoustic and sediment core data from the northeastern part of the lake basin have shown that the lake level of Lake Ohrid was likely 60 m lower during MIS6. The ˜60 m lower lake level at Lake Ohrid during MIS6 can at least partly be explained by the ongoing subsidence, which persists in the basin until today. However, in the DEEP site sediments, the MIS6/MIS5 transition occurs at ca. 50 m sediment depth. This implies that climate-induced lake level fluctuation at Lake Ohrid are less severe compared for example to Lake Van (Turkey), were a 260 m lower lake level has been reported for the Younger Dryas. The imprint of the environmental variations between

  12. Effect of Sea Level Variation on Calculation of Design Water Level

    Institute of Scientific and Technical Information of China (English)

    左军成; 于宜法; 鲍献文; 刘德辅

    2001-01-01

    The long-term variation and seasonal variation of sea level have a notable effect on the calculation of engineering water level. Such an effect is first analyzed in this paper. The maximal amplitude of inter-annual anomaly of monthly mean sea level along the China coast is larger than 60 cm. Both the storm surge disaster and cold wave disaster are sea sonal disasters in various regions, so the water level corresponding to the 1% of the cumulative frequency in the cumulative frequency curve of hourly water level data for different seasons in various sea areas is different from design water level, for example, the difference between them reaches maximum in June, July and August for northern sea area, and maxi.mum in September, October and November for Southern China Sea. The hourly water level data of 19 gauge stations along the China coast are analyzed. Firstly, the annual mean sea level for every station is obtained; secondly, linear chan ging rates of annual mean sea level are obtained with the stochastic dynamic method; thirdly, the astronomical tide and storm surge tide are obtained by subtracting the linear fitting part from the original hourly data, finally, two distributions corresponding to the astronomical tide and wind tide are obtained according to whether the astronomical tide and storm tide are correlative or not. So the two check water levels are obtained with the joint probability method. The maximal difference between the two water levels of 100 years' recurrence is more than 30 cm. Both of the two check water levels have disadvantages in the use of observation data, so the mean value is suggested to be taken as the final check water level. A comparison between the two check water levels indicates that the effect of sea level variation upon design water level and check water level is larger than 80 cm at some stations.

  13. Water levels in the Yucca Mountain Area, Nevada, 1996

    International Nuclear Information System (INIS)

    Water levels were monitored in 24 wells in the Yucca Mountain area, Nevada, during 1996. Twenty-two wells representing 28 depth intervals were monitored periodically, generally on a monthly basis, and 2 wells representing 3 depth intervals were monitored both hourly and periodically. All wells monitor water levels in Tertiary volcanic rocks except one that monitors water levels in paleozoic carbonate rocks. Water levels were measured using either calibrated steel tapes or a pressure sensor. Mean water-level altitudes in the Tertiary volcanic rocks ranged from about 727.86 to about 1,034.58 meters above sea level during 1996. The mean water-level altitude in the well monitoring the Paleozoic carbonate rocks was about 752.57 meters above sea level during 1996. Mean water-level altitudes for 1996 were an average of about 0.06 meter lower than 1995 mean water-level altitudes and 0.03 meter lower than 1985--95 mean water-level altitudes. During 1996, water levels in the Yucca Mountain area could have been affected by long-term pumping at the C-hole complex that began on May 8, 1996. Through December 31, 1996, approximately 196 million liters were pumped from well UE-25 c number-sign 3 at the C-hole complex. Other ground-water pumpage in the Yucca Mountain area includes annual pumpage from water-supply wells UE-25 J-12 and UE-25 J-13 of approximately 163 and 105 million liters, respectively, and pumpage from well USW G-2 for hydraulic testing during February and April 1996 of approximately 6 million liters

  14. Hydraulic Modeling of a Mixed Water Level Control Hydromechanical Gate

    OpenAIRE

    Cassan, Ludovic; Baume, Jean-Pierre; Belaud, Gilles; Litrico, Xavier; Malaterre, Pierre-Olivier; Ribot-Bruno, José

    2011-01-01

    International audience; This article describes the hydraulic behavior of a mixed water level control hydromechanical gate present in several irrigation canals. The automatic gate is termed "mixed" because it can hold either the upstream water level or the downstream water level constant according to the flow conditions. Such a complex behavior is obtained through a series of side tanks linked by orifices and weirs. No energy supply is needed in this regulation process. The mixed flow gate is ...

  15. Water levels in the Yucca Mountain Area, Nevada, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Graves, R.P.

    1998-11-01

    Water levels were monitored in 24 wells in the Yucca Mountain area, Nevada, during 1996. Twenty-two wells representing 28 depth intervals were monitored periodically, generally on a monthly basis, and 2 wells representing 3 depth intervals were monitored both hourly and periodically. All wells monitor water levels in Tertiary volcanic rocks except one that monitors water levels in paleozoic carbonate rocks. Water levels were measured using either calibrated steel tapes or a pressure sensor. Mean water-level altitudes in the Tertiary volcanic rocks ranged from about 727.86 to about 1,034.58 meters above sea level during 1996. The mean water-level altitude in the well monitoring the Paleozoic carbonate rocks was about 752.57 meters above sea level during 1996. Mean water-level altitudes for 1996 were an average of about 0.06 meter lower than 1995 mean water-level altitudes and 0.03 meter lower than 1985--95 mean water-level altitudes. During 1996, water levels in the Yucca Mountain area could have been affected by long-term pumping at the C-hole complex that began on May 8, 1996. Through December 31, 1996, approximately 196 million liters were pumped from well UE-25 c{number_sign}3 at the C-hole complex. Other ground-water pumpage in the Yucca Mountain area includes annual pumpage from water-supply wells UE-25 J-12 and UE-25 J-13 of approximately 163 and 105 million liters, respectively, and pumpage from well USW G-2 for hydraulic testing during February and April 1996 of approximately 6 million liters.

  16. Fluctuating paradigm

    OpenAIRE

    Simmons, L. W.; Tomkins, J. L.; Kotiaho, J. S.; Hunt, J.

    1999-01-01

    A prominent paradigm in evolutionary biology over the last ten years has been the role of fluctuating asymmetry in sexual selection. Fluctuating asymmetry in bilaterally paired traits, and in particular sexual traits, has been proposed to be a reliable indicator of individual quality and the focus of selection through sexual competition and attractiveness. We surveyed the literature on fluctuating asymmetry and sexual selection and found a marked chronological decline in the proportion of stu...

  17. Peatland pines as a proxy for water table fluctuations: disentangling tree growth, hydrology and possible human influence.

    Science.gov (United States)

    Smiljanić, Marko; Seo, Jeong-Wook; Läänelaid, Alar; van der Maaten-Theunissen, Marieke; Stajić, Branko; Wilmking, Martin

    2014-12-01

    Dendrochronological investigations of Scots pine (Pinus sylvestris L.) growing on Männikjärve peatland in central Estonia showed that annual tree growth of peatland pines can be used as a proxy for past variations of water table levels. Reconstruction of past water table levels can help us to better understand the dynamics of various ecological processes in peatlands, e.g. the formation of vegetation patterns or carbon and nitrogen cycling. Männikjärve bog has one of the longest water table records in the boreal zone, continuously monitored since 1956. Common uncertainties encountered while working with peatland trees (e.g. narrow, missing and wedging rings) were in our case exacerbated with difficulties related to the instability of the relationship between tree growth and peatland environment. We hypothesized that the instable relationship was mainly due to a significant change of the limiting factor, i.e. the rise of the water table level due to human activity. To test our hypothesis we had to use several novel methods of tree-ring chronology analysis as well as to test explicitly whether undetected missing rings biased our results. Since the hypothesis that the instable relationship between tree growth and environment was caused by a change in limiting factor could not be rejected, we proceeded to find possible significant changes of past water table levels using structural analysis of the tree-ring chronologies. Our main conclusions were that peatland pines can be proxies to water table levels and that there were several shifting periods of high and low water table levels in the past 200 years.

  18. Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake, 1985 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, Will; Fraley, John J.; Decker-Hess, Janet (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)

    1986-06-01

    This study has investigated the effects of the operation of Kerr Dam on the reproductive success of kokanee that spawn along the shores of Flathead Lake. We have estimated the spawning escapement to the lakeshore, characterized spawning habitat, monitored egg and alevin survival in redds, and related survival to length of redd exposure due to lake drawdown. Groundwater discharge apparently attracts kokanee to spawning sites along the lakeshore and is responsible for prolonging egg survival in redds above minimum pool. We have quantified and described the effect of lake drawdown on groundwater flux in spawning areas. This report defines optimal lakeshore spawning habitat and discusses eqg and alevin survival both in and below the varial zone.

  19. Water levels in the Yucca Mountain area, Nevada, 1995

    International Nuclear Information System (INIS)

    Water levels were monitored in 28 wells in the Yucca Mountain area, Nevada, during 1995. Seventeen wells representing 18 depth intervals were monitored periodically, generally on a monthly basis, 2 wells representing 3 depth intervals were monitored hourly, and 9 wells representing 15 depth intervals were monitored both periodically and hourly. All wells monitor water levels in Tertiary volcanic rocks except one that monitors water levels in Paleozoic carbonate rocks. Water levels were measured using calibrated steel tapes, a multiconductor cable unit, and/or pressure transducers. Mean water-level altitudes in the Tertiary volcanic rocks ranged from about 728 to about 1,034 meters above sea level during 1995. The mean water-level altitude in the well monitoring the Paleozoic carbonate rocks was about 753 meters above sea level during 1995. Mean water level altitudes were only an average of about 0.01 meters higher than 1994 mean water level altitudes. A single-well aquifer test was conducted on well UE-25 WT number-sign 12 during August and September 1995. Well USW 0-2 was also pumped during October and November 1995, in preparation for single-well aquifer test at that well. All data were acquired in accordance with a quality-assurance program to support the reliability of the data

  20. Characteristic of water level changes in river-bed during the 2012 drought in context of ground water levels in a small catchment

    Science.gov (United States)

    Wasilewicz, Michał; Kaznowska, Ewa; Hejduk, Leszek

    2014-05-01

    The objective of this paper is to characterize the water level changes in river bed during the 2012 drought, in the context of ground water levels in the catchment. During the growing season , and long- lasting lack of precipitation causes atmospheric drought. Prolonged lack of precipitation causes depletion of water resources in the saturated zone . Groundwater recharge of rivers decreases , and hence streamflow droughts (summer droughts) occur, which is identified as hydrological droughts. In the phase of hydrological drought a much stronger relationship between surface and ground waters is observed. The study area is the Zagożdżonka river. The Zagożdzonka catchment is situated in the strip of the Central Polish Lowlands, in the region where droughts are the most frequent. The basin is the research area of the Department of Hydraulic Engineering of WUoLS-SGGW in Warsaw. It is one of the few catchments in Poland, with long-term records of rainfall and runoff occurrences. Hydrometeorological measurements are carried out from July 1962. The catchment area is mainly covered by one Quaternary aquifer . Quaternary layer is composed mostly of Pleistocene sands and gravels, with thickness from 4 to 40 m. Aquifer is at a depth of 1 to 12 m below ground level and is unconfined and fed by direct infiltration of precipitation. The Zagożdżonka river is the main drainage in the local hydrologic cycle. There is a strong relationship between surface waters and occurring in the Quaternary sediments. In the hydrological year 2012 hydrological and atmospheric drought occurred. The duration and deficit of streamflow drought ( defined by with the Q90 % truncation level) in 2012 was three time greater than the average value from the multi-annual period, which influenced the groundwater level fluctuations. Acknowledgment The paper has been prepared with financial support by a grant from National Science Centre

  1. Differential equations governing slip-induced pore-pressure fluctuations in a water-saturated granular medium

    Science.gov (United States)

    Iverson, R.M.

    1993-01-01

    Macroscopic frictional slip in water-saturated granular media occurs commonly during landsliding, surface faulting, and intense bedload transport. A mathematical model of dynamic pore-pressure fluctuations that accompany and influence such sliding is derived here by both inductive and deductive methods. The inductive derivation shows how the governing differential equations represent the physics of the steadily sliding array of cylindrical fiberglass rods investigated experimentally by Iverson and LaHusen (1989). The deductive derivation shows how the same equations result from a novel application of Biot's (1956) dynamic mixture theory to macroscopic deformation. The model consists of two linear differential equations and five initial and boundary conditions that govern solid displacements and pore-water pressures. Solid displacements and water pressures are strongly coupled, in part through a boundary condition that ensures mass conservation during irreversible pore deformation that occurs along the bumpy slip surface. Feedback between this deformation and the pore-pressure field may yield complex system responses. The dual derivations of the model help explicate key assumptions. For example, the model requires that the dimensionless parameter B, defined here through normalization of Biot's equations, is much larger than one. This indicates that solid-fluid coupling forces are dominated by viscous rather than inertial effects. A tabulation of physical and kinematic variables for the rod-array experiments of Iverson and LaHusen and for various geologic phenomena shows that the model assumptions commonly are satisfied. A subsequent paper will describe model tests against experimental data. ?? 1993 International Association for Mathematical Geology.

  2. Effect of Task-Correlated Physiological Fluctuations and Motion in 2D and 3D Echo-Planar Imaging in a Higher Cognitive Level fMRI Paradigm

    Science.gov (United States)

    Ladstein, Jarle; Evensmoen, Hallvard R.; Håberg, Asta K.; Kristoffersen, Anders; Goa, Pål E.

    2016-01-01

    Purpose: To compare 2D and 3D echo-planar imaging (EPI) in a higher cognitive level fMRI paradigm. In particular, to study the link between the presence of task-correlated physiological fluctuations and motion and the fMRI contrast estimates from either 2D EPI or 3D EPI datasets, with and without adding nuisance regressors to the model. A signal model in the presence of partly task-correlated fluctuations is derived, and predictions for contrast estimates with and without nuisance regressors are made. Materials and Methods: Thirty-one healthy volunteers were scanned using 2D EPI and 3D EPI during a virtual environmental learning paradigm. In a subgroup of 7 subjects, heart rate and respiration were logged, and the correlation with the paradigm was evaluated. FMRI analysis was performed using models with and without nuisance regressors. Differences in the mean contrast estimates were investigated by analysis-of-variance using Subject, Sequence, Day, and Run as factors. The distributions of group level contrast estimates were compared. Results: Partially task-correlated fluctuations in respiration, heart rate and motion were observed. Statistically significant differences were found in the mean contrast estimates between the 2D EPI and 3D EPI when using a model without nuisance regressors. The inclusion of nuisance regressors for cardiorespiratory effects and motion reduced the difference to a statistically non-significant level. Furthermore, the contrast estimate values shifted more when including nuisance regressors for 3D EPI compared to 2D EPI. Conclusion: The results are consistent with 3D EPI having a higher sensitivity to fluctuations compared to 2D EPI. In the presence partially task-correlated physiological fluctuations or motion, proper correction is necessary to get expectation correct contrast estimates when using 3D EPI. As such task-correlated physiological fluctuations or motion is difficult to avoid in paradigms exploring higher cognitive functions, 2

  3. Study on convective mixing phenomena in parallel triple-jet along wall. Comparison of temperature fluctuation characteristics between sodium and water

    Energy Technology Data Exchange (ETDEWEB)

    Nobuyuki Kimura; Hiroyuki Miyakoshi; Hiroshi Ogawa; Hideki Kamide [O-arai Engineering Center, Japan Nuclear Cycle Development Institute, 4002 Narita, O-arai, Ibaraki, 311-1393 (Japan); Yasuhiro Miyake [NDD Corporation, Hope building 8F, 1-7-23, Minato, Tsuchiura, Ibaraki, 300-0034 (Japan); Kazuyoshi Nagasawa [NESI Incorporation, 4002 Narita, O-arai, Ibaraki, 311-1313 (Japan)

    2005-07-01

    Full text of publication follows: When temperature fluctuation due to convective mixing between hot and cold fluids is transferred to structure, there is a possibility of high cycle thermal fatigue. In a fast reactor sodium is used as coolant. Many experiments and calculations using water as working fluid have been carried out for the temperature fluctuations. As regarding sodium there are few experimental data. Sodium has approximately a 100 times larger thermal conductivity than water though dynamic viscosity is the same order. So temperature fluctuation characteristics in sodium will be different from that in water. Especially, decay characteristics of temperature fluctuation near a wall surface are strongly influenced by thermal property of fluid in a boundary layer. This is of importance to evaluate transfer characteristics of temperature fluctuation from fluid to structure. Here, sodium and water experiments were performed using the same geometry of the test sections. These experimental apparatuses have parallel triple jets sandwiched with two partition plates. The triple jets flow vertically along a wall with convective mixing among the jets. The jet in the center is cold, and two jets in both sides are hot. The discharged velocities of the triple jets were 0.5 m/s in both experiments. The temperature data were obtained by movable thermocouple trees, which consisted of 25 to 40 thermocouples. The temperatures were measured at 0.5 mm from the wall surface to the center position between the two partition plates. In addition, a particle image velocimetry was applied to the water experiment. As for the time-averaged temperature field at the furthest position from the wall, the hot jets were inclined toward the cold jet in both experiments. Temperature fluctuation intensity was high in the region where the cold jet met the hot jets. A prominent frequency was observed in temperature fluctuation where the cold jet contacted the hot jets; it was resulted from

  4. Analysis of Ground-Water Levels and Associated Trends in Yucca Flat, Nevada Test Site, Nye County, Nevada, 1951-2003

    Energy Technology Data Exchange (ETDEWEB)

    J.M. Fenelon

    2005-10-05

    Almost 4,000 water-level measurements in 216 wells in the Yucca Flat area from 1951 to 2003 were quality assured and analyzed. An interpretative database was developed that describes water-level conditions for each water level measured in Yucca Flat. Multiple attributes were assigned to each water-level measurement in the database to describe the hydrologic conditions at the time of measurement. General quality, temporal variability, regional significance, and hydrologic conditions are attributed for each water-level measurement. The database also includes narratives that discuss the water-level history of each well. Water levels in 34 wells were analyzed for variability and for statistically significant trends. An attempt was made to identify the cause of many of the water-level fluctuations or trends. Potential causes include equilibration following well construction or development, pumping in the monitoring well, withdrawals from a nearby supply well, recharge from precipitation, earthquakes, underground nuclear tests, land subsidence, barometric pressure, and Earth tides. Some of the naturally occurring fluctuations in water levels may result from variations in recharge. The magnitude of the overall water-level change for these fluctuations generally is less than 2 feet. Long-term steady-state hydrographs for most of the wells open to carbonate rock have a very similar pattern. Carbonate-rock wells without the characteristic pattern are directly west of the Yucca and Topgallant faults in the southwestern part of Yucca Flat. Long-term steady-state hydrographs from wells open to volcanic tuffs or the Eleana confining unit have a distinctly different pattern from the general water-level pattern of the carbonate-rock aquifers. Anthropogenic water-level fluctuations were caused primarily by water withdrawals and nuclear testing. Nuclear tests affected water levels in many wells. Trends in these wells are attributed to test-cavity infilling or the effects of

  5. Synthesis water level control by fuzzy logic

    Directory of Open Access Journals (Sweden)

    P. Berk

    2011-04-01

    Full Text Available Purpose: This paper focuses on evolving of two types fuzzy and classical PID liquid level controller and examining whether they are better able to handle modelling uncertainties. A two stage strategy is employed to design the synthesis fuzzy and classical PID controller with the process of the first and second order and implements disorder (quadratic function.Design/methodology/approach: The synthesis of fuzzy and classical PID liquid level controller was realized with the HP laptop 6830s Compaq NA779ES, software Matlab/Simulink 2008b, FIS (Fuzzy Inference System soft logical tool, input-output unit 500 Dragon Rider and ultrasonic sensor. Using the simulation program Matlab/Simulink/FIS we simulate the operation of fuzzy and classical controller in the liquid level regulating cycle and made a comparison between fuzzy and classical controller functioning.Findings: From the responses to step fuzzy and classical controller for first-order process shows that the actual value of the controlled variable takes the value one. Fuzzy and classical PID controller does not allow control derogation, which is also inappropriate for fuzzy and classical control cycle with incorporating disturbance. Classical PID controller in the first-order process provides short-term regulation, such as fuzzy PID controller. In fuzzy control cycle with fuzzy PID controller and incorporating disturbance in the process of second-order the control cycle is stable and at certain predetermined parameters (integral gain a control does not allow deviations.Research limitations/implications: In future research, the robustness of the fuzzy logic controller will be investigated in more details.Practical implications: Using fuzzy liquid level controller can reduce power consumption by 25%. Originality/value: Fuzzy logic controller is useful in applications of nonlinear static characteristic, where classical methods with usually classical PID controllers cannot be a satisfactory outcome

  6. The Influence of a Fluctuating Water Table on Arsenic Mobility in a Western U.S. Aquifer

    OpenAIRE

    Abu-Ramaileh, Allia Maher

    2015-01-01

    Arsenic (As) concentrations in groundwater that exceed the Maximum Contaminant Level (MCL) (10 μg/L) for drinking water have been reported throughout the United States, with higher occurrences in the Southwestern basin-fill aquifers. Levels of As above the MCL were measured in wells throughout the Cache Valley Basin, Utah. The As is naturally occurring in geologic material from the soil surface to depths of groundwater. This study reports on the mechanisms of retention and solubilization of A...

  7. Stochastic Liouville equations for hydrogen-bonding fluctuations and their signatures in two-dimensional vibrational spectroscopy of water

    NARCIS (Netherlands)

    Jansen, TL; Hayashi, T; Zhuang, W; Mukamel, S

    2005-01-01

    The effects of hydrogen-bond forming and breaking kinetics on the linear and coherent third-order infrared spectra of the OH stretch of HOD in D2O are described by Markovian, not necessarily Gaussian, fluctuations and simulated using the stochastic Liouville equations. Slow (0.5 ps) fluctuations are

  8. Subtidal water level variation controlled by river flow and tides

    NARCIS (Netherlands)

    Buschman, F.A.; Hoitink, A.J.F.; Vegt, van der M.; Hoekstra, P.

    2009-01-01

    Subtidal water level dynamics in the Berau river, East Kalimantan, Indonesia, feature a pronounced fortnightly variation. The daily mean water levels at a station about 60 km from the sea are 0.2–0.6 m higher during spring tide than during neap tide. To explain the underlying mechanisms, a local sub

  9. Growth and lipid accumulation of microalgae from fluctuating brackish and sea water locations in South East Queensland – Australia

    Directory of Open Access Journals (Sweden)

    Van Thang eDuong

    2015-05-01

    Full Text Available One challenge constraining the use of microalgae in the food and biofuels industry is growth and lipid accumulation. Microalgae with high growth characteristics are more likely to originate from the local environment. However, to be commercially effective, in addition to high growth microalgae must also have high lipid productivities and contain the desired fatty acids for their intended use. We isolated microalgae from intertidal locations in South East Queensland, Australia with adverse or fluctuating conditions, as these may harbor more opportunistic strains with high lipid accumulation potential. Screening was based on a standard protocol using growth rate and lipid accumulation as well as prioritizing fatty acid profiles suitable for biodiesel or nutraceuticals. Using these criteria, an initial selection of over 50 local microalgae strains from brackish and sea water was reduced to 16 strains considered suitable for further investigation. Among these 16 strains, the ones most likely to be effective for biodiesel feedstock were Nitzschia sp. CP3a, Tetraselmis sp. M8, Cymbella sp. CP2b and Cylindrotheca closterium SI1c, reaching growth rates of up to 0.53 day-1 and lipid productivities of 5.62 µg mL-1day-1. Omega-3 fatty acids were found in some strains such as Nitzschia sp. CP2a, Nitzschia sp. CP3a and Cylindrotheca closterium SI1c. These strains have potential for further research as commercial food supplements.

  10. Tectonic and climate driven fluctuations in the stratigraphic base level of a Cenozoic continental coal basin, northwestern Andes

    Science.gov (United States)

    Silva Tamayo, J. C.; Sierra, G. M.; Correa, L. G.

    2008-12-01

    Changes in the sedimentologic and stratigraphic characteristics of the coal-bearing middle Oligocene-late Miocene siliciclastic Amagá Formation, northwestern Colombia, reflect major fluctuations in the stratigraphic base level within the Amagá Basin, which paralleled three major stages of evolution of the middle Cenozoic Andean Orogeny. These stages, which are also traceable by the changes in the compositional modes of sandstones, controlled the occurrence of important coal deposits. The initial stage of evolution of the Amagá Basin was related to the initial uplift of the Central Cordillera of Colombia around 25 Ma, which promoted moderate subsidence rates and high rates of sediment supply into the basin. This allowed the development of aggradational braided rivers and widespread channel amalgamation resulting in poor preservation of both, low energy facies and geomorphic elements. The presence of poorly preserved Alfisols within the scarce flood plains and the absence of swamp deposits suggest arid climate during this stage. The compositional modes of sandstones suggest sediment supply from uplifted basement-cored blocks. The second stage of evolution was related to the late Oligocene eastward migration of the Pre-Andean tholeitic magmatic arc from the Western Cordillera towards the Cauca depression. This generated extensional movements along the Amagá Basin, enhancing the subsidence and increasing the accommodation space along the basin. As a result of the enhanced subsidence rates, meandering rivers developed, allowing the formation of extensive swamps deposits (currently coal beds). The excellent preservation of Entisols and Alfisols within the flood plain deposits suggests rapid channels migration and a humid climate during deposition. Moderate to highly mature channel sandstones support this contention, and point out the Central Cordillera of Colombia as the main source of sediment. Enhanced subsidence during this stage also prevented channels

  11. Using continuous surface water level and temperature data to characterize hydrological connectivity in riparian wetlands.

    Science.gov (United States)

    Cabezas, Alvaro; Gonzalez-Sanchís, Maria; Gallardo, Belinda; Comín, Francisco A

    2011-12-01

    Methods to characterize hydrological connectivity at riparian wetlands are necessary for ecosystem management given its importance over ecosystem structure and functioning. In this paper, we aimed to describe hydrological connectivity at one Ebro River reach (NE Spain) and test a method to perform such characterization. Continuous surface water level and temperature data were recorded at five riparian wetlands during the period October 2006-June 2007. Combining water level and temperature, we classified the examined wetlands in three groups, which mainly differed in the dominant water source during different flood stages. Firstly, a comparison of water level fluctuations in riparian wetlands with those in the river channel during events with different characteristics was used to describe hydrological connectivity. Such comparison was also used to extract quantitative hydrological connectivity descriptors as the wetland response initiation time. Secondly, water temperature series were divided in phases with different average, range and daily oscillation, and these parameters were interpreted for each phase to identify dominant flowpaths. By doing so, a more complete description of hydrological connectivity was achieved. Our method provided useful insights to describe hydrological connectivity using a qualitative approach that can be expanded if required to include quantitative parameters for studies of biotic assemblages or ecosystem processes. PMID:21400244

  12. Calculating Skempton constant of aquifer from volume strain and water level response to seismic waves at Changping seismic station

    Institute of Scientific and Technical Information of China (English)

    YAN Rui; CHEN Yong; GAO Fu-wang; HUANG Fu-qiong

    2008-01-01

    Based on linear poroelastic theory of ideal poroelastic media, we apply the mathematic expression between pore pressure and volume strain for well-aquifer system to analyzing the observed data of water level and volume strain changes aroused by Sumatra Ms8.7 (determined by China Seismic Networks Center) seismic waves at Changping, Beijing, station on December 26, 2004 from both time and frequency domain. The response coefficients of water level fluctuation to volume strain are also calculated when seismic waves were passing through confined aquifer. A method for estimating Skempton constant B is put forward, which provide an approach for understanding of the characteristics of aquifer.

  13. A multi-source satellite data approach for modelling Lake Turkana water level: Calibration and validation using satellite altimetry data

    Science.gov (United States)

    Velpuri, N.M.; Senay, G.B.; Asante, K.O.

    2012-01-01

    Lake Turkana is one of the largest desert lakes in the world and is characterized by high degrees of interand intra-annual fluctuations. The hydrology and water balance of this lake have not been well understood due to its remote location and unavailability of reliable ground truth datasets. Managing surface water resources is a great challenge in areas where in-situ data are either limited or unavailable. In this study, multi-source satellite-driven data such as satellite-based rainfall estimates, modelled runoff, evapotranspiration, and a digital elevation dataset were used to model Lake Turkana water levels from 1998 to 2009. Due to the unavailability of reliable lake level data, an approach is presented to calibrate and validate the water balance model of Lake Turkana using a composite lake level product of TOPEX/Poseidon, Jason-1, and ENVISAT satellite altimetry data. Model validation results showed that the satellitedriven water balance model can satisfactorily capture the patterns and seasonal variations of the Lake Turkana water level fluctuations with a Pearson's correlation coefficient of 0.90 and a Nash-Sutcliffe Coefficient of Efficiency (NSCE) of 0.80 during the validation period (2004-2009). Model error estimates were within 10% of the natural variability of the lake. Our analysis indicated that fluctuations in Lake Turkana water levels are mainly driven by lake inflows and over-the-lake evaporation. Over-the-lake rainfall contributes only up to 30% of lake evaporative demand. During the modelling time period, Lake Turkana showed seasonal variations of 1-2m. The lake level fluctuated in the range up to 4m between the years 1998-2009. This study demonstrated the usefulness of satellite altimetry data to calibrate and validate the satellite-driven hydrological model for Lake Turkana without using any in-situ data. Furthermore, for Lake Turkana, we identified and outlined opportunities and challenges of using a calibrated satellite-driven water balance

  14. Water level changes of high altitude lakes in Himalaya–Karakoram from ICESat altimetry

    Indian Academy of Sciences (India)

    Priyeshu Srivastava; Rakesh Bhambri; Prashant Kawishwar; D P Dobhal

    2013-12-01

    Himalaya–Karakoram (H–K) region hosts large number of high altitude lakes but are poorly gauged by in-situ water level monitoring method due to tough terrain conditions and poor accessibility. After the campaigns of ICESat during 2003–2009, now it is possible to achieve lake levels at decimetre accuracy. Therefore, in present study, high altitude lake levels were observed using ICESat/GLAS altimetry in H–K between 2003 and 2009 to generate baseline information. The study reveals that out of 13 lakes, 10 lakes show increasing trend of water levels at different rate (mean rate 0.173 m/y) whereas three lakes unveiled decreasing trend (mean rate −0.056 m/y). Out of five freshwater lakes, four lakes show an increasing trend of their level (mean rate 0.084 m/y) whereas comparatively six salt lakes (out of seven salt lakes) exhibited ∼3 times higher mean rate of lake level increase (0.233 m/y). These observed lake level rise can be attributed to the increased melt runoffs (i.e., seasonal snow and glacier melts) owing to the enhanced mean annual and seasonal air temperature during past decade in north-western (NW) Himalaya. Further, varied behaviours of lake level rises in inter- and intra-basins suggest that the local climatic fluctuations play prominent role along with regional and global climate in complex geographical system of NW Himalaya.

  15. Assessment of radon levels in some water resources in Egypt

    International Nuclear Information System (INIS)

    Radon is a naturally occurring radioactive gas that is produced by the radioactive decay of radium. Breathing high concentrations of radon can cause lung cancer. When radon gas migrates through the atmosphere, the solid radon progeny are deposited on the soil and water below, entering into the food chain. Radon generated from rocks containing its parents may escape to the underground or surface running water, which ultimately used as drinking water or for irrigation. In this work radon level was determined in different water resources in Egypt. Water from spring, tap water Nile and some commercially available drinking water were subjected to radon measurements using CR-39 detectors. Radon concentration in different water resources was found the range from 8.94 to 10.00 Bq/m3 while in trapped air above water was 9.3 to 10.38 Bq/m3

  16. Response of the Apodi-Mossoró estuary-incised valley system (NE Brazil to sea-level fluctuations

    Directory of Open Access Journals (Sweden)

    Helenice Vital

    2010-01-01

    Full Text Available This study focuses on the Quaternary sea level changes in the Apodi-Mossoró Estuary and adjacent shelf, Northeastern Brazil, based on the analysis of high-resolution seismic profiles, integrated with echosounder, SRTM and satellite image data. We use these data to develop a relative stratigraphy. An incised-valley extending from the Apodi-Mossoró Estuary onto the shelf dominates the investigated area. In very shallow waters (down to 10 m depth the channel lies mainly in a NW-SE direction, changing to NE-SW in waters below10 m, in the form of a J-shaped valley. The southern flank of the shallow channel presents an abrupt morphology, probably determined by a residual scarp due to neotectonic reactivation of a pre-existing fault. This incised-valley can be correlated with a former river valley formed during the late Pleistocene fall in sea-level. The base-level change related to this drop in sea level can be regionally expressed on seismic lines as a laterally-continuous stratigraphic surface named Horizon I, interpreted as representing the sub-aerial exposure of the continental shelf. Many incised valleys were excavated on this exposed shelf, including that of the Apodi-Mossoró Estuary and its incised valley system. This incised valley has lain buried since the Holocene transgression. The Holocene sediments present sub-horizontal layers, or they have filled the incised valley with oblique features.Este estudo utiliza a integração de dados sísmicos de alta resolução, batimétricos, SRTM e imagens de satélite para desenvolvimento da estratigrafia relativa visando entender as variações do nível do mar durante o Quaternário no estuário do rio Apodi-Mossoró e plataforma adjacente, nordeste do Brasil. A principal feição identificada foi um canal submerso, na plataforma interna, parcialmente preenchido, provavelmente relacionado com o sistema de vales incisos formado durante o rebaixamento do nível do mar no Pleistoceno. O canal

  17. Maximum permissible level of radio activity in drinking water

    Directory of Open Access Journals (Sweden)

    P. C. Gupta

    1960-10-01

    Full Text Available The possible for contamination of water by radio activity due to radioisotopes which can be ingested by drinking contaminated water have been discussed. The factors on which hazards associated with radioactive contamination have been dealt with in detail. The maximum permissible level of radioisotopes in water as laid down by the I.R.P.C., U.K. and U.S.A. are compared. To meet emergencies certain emergency permissible levels of radioactivity have been suggested, giving the importance of these levels. Lastly, some precautionary measures for protection and methods for decontamination have been explained.

  18. Potential effects of climate change on the water level, flora and macro-fauna of a large neotropical wetland.

    Directory of Open Access Journals (Sweden)

    Bárbara Úbeda

    Full Text Available Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds. On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication presents an important challenge to the conservation of neotropical wetlands in the coming decades.

  19. Flashing characteristics in pipe downstream from a depressurizing tank and temperature fluctuation characteristics at a mixing tee junction with cold water injection

    International Nuclear Information System (INIS)

    The flashing characteristics in a pipe downstream from a depressurizing tank were experimentally and analytically investigated on the basis of the transient test and two-phase flow analysis. The following three conclusions were obtained. (1) When the pressure margin of the pump inlet side and the distance to obtain an isothermal condition were sufficient, flashing phenomena did not occur in spite of the decreasing pressure. (2) When the ratio of the cold water injection flow rate to the hot water flow rate Mc/Mh increased, the peak distance of the water temperature fluctuation moved from L/D=1 to 0, and the maximum water temperature fluctuation ratio was about 40% of the temperature difference between hot and cold water near the mixing tee junction. But no problem occurred regarding the pipe material thermal fatigue, so reliability of the mixing tee junction was assured. (3) Due to suppression of flashing phenomena of the mixing pipe system, the decision diagram on the flashing occurrence was obtained from test and analytical results, taking into consideration three factors : the depressurizing ratio in the tank ; the cold water injection flow rate due to remaining sub-cooling ; and the delay time of thermal mixing. The simplified analytical equation was used to decrease the cold water injection flow rate by the optimized pipe length between the mixing tee junction and drain pump. The cold water injection flow rate was minimized when pipe length was about 15 to 20 times the pipe inner diameter. (author)

  20. Estimation of Peak Water Level in Pearl River Estuary under the Background of Sea Level Rise

    Institute of Scientific and Technical Information of China (English)

    KONG; Lan; CHEN; Xiao-hong; ZHUANG; Cheng-bin; CHEN; Dong-wei

    2012-01-01

    [Objective] The study aimed to predict the peak water level in Pearl River Estuary under the background of sea level rise. [Method] The changing trends of peak water level at Denglongshan station and Hengmen station were analyzed firstly on the basis of regression models, and then sea level rise in Pearl River Estuary in 2050 was predicted to estimate the 1-in-50-year peak water level in the same year. [Result] Regression analyses showed that the increasing rate of peak water level over past years was 6.3 mm/a at Denglongshan station and 5.8 mm/a at Hengmen station. In addition, if sea level will rise by 20, 30 and 60 cm respectively in 2050, it was predicted that the 1-in-50-year peak water level will reach 3.04, 3.14 and 3.44 m at Denglongshan station, and 3.19, 3.29 and 3.59 m at Hengmen station separately. [Conclusion] The estimation of peak water level in Pearl River Estuary could provide theoretical references for water resources planning.

  1. Modelling soil water dynamics and crop water uptake at the field level

    NARCIS (Netherlands)

    Kabat, P.; Feddes, R.A.

    1995-01-01

    Parametrization approaches to model soil water dynamics and crop water uptake at field level were analysed. Averaging and numerical difficulties in applying numerical soil water flow models to heterogeneous soils are highlighted. Simplified parametrization approaches to the soil water flow, such as

  2. Water level influences on body condition of Geophagus brasiliensis (Perciformes: Cichlidae in a Brazilian oligotrophic reservoir

    Directory of Open Access Journals (Sweden)

    Alejandra Filippo Gonzalez Neves dos Santos

    2004-09-01

    Full Text Available Effects of water level fluctuations on body condition of Geophagus brasiliensis were studied in a 30 km² Brazilian oligotrophic reservoir. Physiological condition (K and gonadosomatic index (GSI were compared according to water level (low and high. Females' best conditions were associated to higher resources availability during high water, since gonad development did not change between low and high water. Males' condition did not change between water levels, while the highest gonad development occurred in low water. Females presented higher reproductive investment than males, which allocated most of energy for somatic development. This strategy could be a mechanism to undergo the stress caused by oligotrophic characteristics of the reservoir enhanced during low water level.Efeitos do nível da água na condição de Geophagus brasiliensis foram analisados em um reservatório oligotrófico. A condição fisiológica (K e o índice gonadossomático (IGS foram comparados entre os níveis da água (baixo e alto. Melhores condições de fêmeas foram associadas a maiores disponibilidades de recursos no nível alto, já que o desenvolvimento gonadal não variou. Não foram registradas diferenças na condição de machos, contudo maiores valores de IGS ocorreram no nível baixo. Fêmeas apresentaram elevado investimento reprodutivo, enquanto machos investiram mais no desenvolvimento somático. Tal estratégia pode ser um mecanismo para suportar o estresse causado pelas características oligotróficas do reservatório, intensificadas durante o período de níveis baixos da água.

  3. A near-uniform fluctuation of ocean bottom pressure and sea level across the deep ocean basins of the Arctic Ocean and the Nordic Seas

    Science.gov (United States)

    Fukumori, Ichiro; Wang, Ou; Llovel, William; Fenty, Ian; Forget, Gael

    2015-05-01

    Across the Arctic Ocean and the Nordic Seas, a basin-wide mode of ocean bottom pressure and sea level fluctuation is identified using satellite and in situ observations in conjunction with a global ocean circulation model and its adjoint. The variation extends across the interconnected deep ocean basins of these semi-enclosed Arctic seas, collectively called the Arctic Mediterranean, with spatially near-uniform amplitude and phase. The basin-wide fluctuation is barotropic and dominates the region's large-scale variability from sub-monthly to interannual timescales. The fluctuation results from bifurcating coastally trapped waves generated by winds along the continental slopes of the Arctic Mediterranean and its neighboring seas, including the North Atlantic Ocean. The winds drive Ekman transport across the large bathymetric gradients, forcing mass divergence between the shallow coastal area and the deep ocean basins and creating ocean bottom pressure anomalies of opposite signs in the two regions. The anomalies rapidly propagate away as barotropic coastally trapped waves with the coast and continental slope as respective boundaries. The waves subsequently bifurcate at the shallow straits connecting the Arctic Mediterranean with the rest of the globe. The straits transmit the shallow anomalies but not the deep variations, thereby inhibiting the anomalies' mutual cancelation by geographically separating the two. Anomalies that enter the deep Arctic basins equilibrate uniformly across the domain characterized by a homogeneous depth-integrated planetary potential vorticity distribution. The potential vorticity's steep gradient that borders the basins shields the region from neighboring shallow variations, giving rise to the observed spatially confined fluctuation. Compensating anomalies outside the Arctic adjust similarly across the rest of the globe but are comparatively negligible in amplitude because of the global ocean's larger area relative to that of the deep

  4. Characterization of Water Level Variability of the Main Ethiopian Rift Valley Lakes

    Directory of Open Access Journals (Sweden)

    Mulugeta Dadi Belete

    2015-12-01

    Full Text Available In this paper, the water level fluctuations of eight Ethiopian Rift Valley lakes were analyzed for their hydrological stability in terms of water level dynamics and their controlling factors. Long-term water balances and morphological nature of the lakes were used as bases for the analyses. Pettit’s homogeneity test and Mann–Kendall trend analysis were applied to test temporal variations of the lake levels. It is found that the hydrological stability of most of the Ethiopian Rift Valley lakes is sensitive to climate variability. In terms of monotonic trends, Lake Ziway, Hawassa, Abaya and Beseka experienced significant increasing trend, while Ziway, Langano and Chamo do not. In addition, homogeneity test revealed that Lake Hawassa and Abaya showed significant upward shift around 1991/1992, which was likely caused by climate anomalies such as the El Niño / Southern Oscillation (ENSO phenomena. Lake Abiyata is depicted by its significant decreasing monotonic trend and downward regime shift around 1984/1985, which is likely related to the extended water abstraction for industrial consumption.

  5. Contribution of climate-driven change in continental water storage to recent sea-level rise

    Science.gov (United States)

    Milly, P.C.D.; Cazenave, A.; Gennero, M.C.

    2003-01-01

    Using a global model of continental water balance, forced by interannual variations in precipitation and near-surface atmospheric temperature for the period 1981-1998, we estimate the sea-level changes associated with climate-driven changes in storage of water as snowpack, soil water, and ground water; storage in ice sheets and large lakes is not considered. The 1981-1998 trend is estimated to be 0.12 mm/yr, and substantial interannual fluctuations are inferred; for 1993-1998, the trend is 0.25 mm/yr. At the decadal time scale, the terrestrial contribution to eustatic (i.e., induced by mass exchange) sea-level rise is significantly smaller than the estimated steric (i.e., induced by density changes) trend for the same period, but is not negligibly small. In the model the sea-level rise is driven mainly by a downtrend in continental precipitation during the study period, which we believe was generated by natural variability in the climate system.

  6. Water level and vegetation change analysis at Stillwater Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The aim of the project summarized in this report was to determine the feasibility of detecting change in surface water levels and associated wetland biomass at the...

  7. Water-level change, High Plains aquifer, 1980 to 1995

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1980 to 1995, in feet. The High Plains aquifer underlies...

  8. Water-level change, High Plains aquifer, 2000 to 2005

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2000 to 2005, in feet. The High Plains aquifer underlies...

  9. Water-level change, High Plains aquifer, 2005 to 2009

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 2005 to 2009, in feet. The High Plains aquifer underlies...

  10. Water-level change, High Plains aquifer, 1995 to 2000

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This raster data set represents water-level change in the High Plains aquifer of the United States from 1995 to 2000, in feet. The High Plains aquifer underlies...

  11. 2012 Water Levels - Mojave River and the Morongo Groundwater Basins

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — During 2012, the U.S. Geological Survey and other agencies made approximately 2,500 water-level measurements in the Mojave River and Morongo groundwater basins....

  12. NOS CO-OPS Water Level Data, Preliminary, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has recent, preliminary (not quality-controlled), 6-minute, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and...

  13. NOS CO-OPS Water Level Data, Verified, Hourly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has verified (quality-controlled), hourly, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS)....

  14. NOS CO-OPS Water Level Data, Verified, High Low

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has verified (quality-controlled), daily, high low water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and Services...

  15. NOS CO-OPS Water Level Data, Verified, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has verified (quality-controlled), 6-minute, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS)....

  16. NOS CO-OPS Water Level Data, Preliminary, 1-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has recent, preliminary (not quality-controlled), 1-minute, water level (tide) data from NOAA NOS Center for Operational Oceanographic Products and...

  17. Stable isotope fingerprint of open-water evaporation losses and effective drainage area fluctuations in a subarctic shield watershed

    Science.gov (United States)

    Gibson, J. J.; Reid, R.

    2010-02-01

    SummaryStable isotopes of water, oxygen-18 and deuterium, were measured at biweekly to monthly intervals during the open-water season in a small, headwater lake (Pocket Lake, 4.8 ha) near Yellowknife Northwest Territories, and concurrently in a nearby string-of-lakes watershed (Baker Creek, 137 km 2) situated in the subarctic Precambrian Shield region. As measured in water samples collected over a 12 year period (1997-2008), the levels of evaporative isotopic enrichment in both lake and watershed outflow were differentially offset, and seasonal variations were found in both to be driven by variations in open-water evaporation. Systematic differences measured in the magnitude of the offset between the lake and watershed outflow are interpreted as being caused by changes in the effective drainage area contributing to runoff. Based on the observed and extremely consistent relationship between isotopic compositions of lake water and watershed outflow ( r2 = 0.849, p isotopic signals transferred downstream in a typical shield drainage system within the Mackenzie Basin.

  18. Radium-226 levels in Italian drinking waters and foods

    International Nuclear Information System (INIS)

    Levels of 226Ra in Italian waters and foods were measured. Results were similar to those found in other countries, except for some mineral waters with 226Ra concentrations above 1 pCi/liter andup to 19 pCi/liter. No difinite correlation was found between the 226Ra concentrations measured and the high natural background radiation levels determined in central Italy in previous work

  19. Solar Driven Automatic Water Level Controller with Dry Run Protection

    Directory of Open Access Journals (Sweden)

    V. Ravikiran,

    2015-11-01

    Full Text Available This paper presents solar driven automatic water level controller with dry run protection (SDWLC. The main purpose of SDWLC is to reduce wastage of water, to stop dry running of motor and to use solar energy effectively by using PV system. Generally water is pumped to overheadtank (OHT from undergroundtank (UGT.People will switch on pump when taps go dry, switch off pump when water over flows and they does not check dry running of motor during this. Also pumping of water to OHT during power cuts is a major problem in most of villages and in some of cities. However these problems can be solved by SDWLC. By using inverter the DC generated from PV system is converted in to AC and given to the motor. The operation of water level controller works upon the fact that water conducts electricity. So water can be used to open or close a circuit. As the water level rises or falls, different circuits in the controller send different signals. These signals are used to switch ON or switch OFF the motor pump as per our requirements.

  20. Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Erickson, Melinda L.

    2016-10-19

    OverviewThis study assessed lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes applying three approaches: statistical analysis, field study, and groundwater-flow modeling.  Statistical analyses of lake levels were completed to assess the effect of physical setting and climate on lake-level fluctuations of selected lakes. A field study of groundwater and surface-water interactions in selected lakes was completed to (1) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (2) estimate general ages for waters extracted from the wells, and (3) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake.  Groundwater flow was simulated using a steady-state, groundwater-flow model to assess regional groundwater and surface-water exchanges and the effects of groundwater withdrawals, climate, and other factors on water levels of northeast Twin Cities Metropolitan Area lakes.

  1. 随机浅海声传播简正波起伏%Normal mode fluctuation of sound propagating in random shallow water

    Institute of Scientific and Technical Information of China (English)

    彭临慧; 王桂波

    2006-01-01

    Research of fluctuation of sound propagation in a random shallow water environment is of great interest in predicting sound field and environmental parameters for random ocean investigation and monitoring. This paper studies the normal mode fluctuation of sound propagation in random shallow water. Monte Carlo simulation is used to analyze the sound field fluctuation induced by sound speeds random fluctuation with Dozier's statistical coupled mode equations in a random ocean. The random sound speed model is derived based on the statistic analysis of a temperature chain data in shallow sea. The results show that the amplitude fluctuation of normal mode induced by sound speed random fluctuation is larger than the amplitude fluctuation of sound pressure. If the source position is close to the sensitive depth of a normal mode, the scintillation index of this normal mode would be 2~3 order of magnitude larger than the variance of normal mode amplitude fluctuation. As such, the scintillation index of normal mode is an important parameter for detecting sound propagating fluctuation. This article reveals that variance of the sound pressure fluctuation is linear against distance, variance of normal mode amplitude fluctuation, and modal scintillation index.%随机浅海环境中声传播起伏的研究,对于随机海洋环境声场预报及海洋环境参数反演和遥测都有十分重要的意义.文中对随机浅海中声传播的简正波起伏进行了研究,利用L.B.Dozier统计耦合模式方程,通过Monte Carlo数值模拟分析声速场随机变化所产生的声场起伏规律.随机声速场模型由海上温度链测量数据统计规律分析得到.结果表明,声速场随机起伏所导致的简正波幅度起伏远高于声压的起伏;当声源处在某一阶简正波的敏感深度位置时,该阶简正波的闪烁系数会比简正波幅度起伏方差高2~3个量级;在所分析随机声速场模型下,声压起伏方差、简正波幅度起伏

  2. Non-renewable water use on the globe and its implication to sea level change

    Science.gov (United States)

    Oki, T.; Pokhrel, Y. N.; Hanasaki, N.; Koirala, S.; Kanae, S.

    2012-12-01

    The real hydrological cycles on the Earth are not natural anymore. Global hydrological model simulations of the water cycle and available water resources should have an ability to consider the effects of human interventions on hydrological cycles. Anthropogenic activity modules, such as reservoir operation, crop growth and water demand in croplands, and environmental flows, were incorporated into a land surface model to form a new model, MAT-HI. Total terrestrial water storages (TWS) in large river basins were estimated using the new model by off-line simulation, and compared with the TWS observed by GRACE for 2002-2007. MAT-HI was further coupled with a module representing the ground water level fluctuations, and consists a new land surface scheme HiGW-MAT (Human Intervention and Ground Water coupled MATSIRO). HiGW-MAT is also associated with a scheme tracing the origin and flow path with the consideration on the sources of water withdrawal from stream flow, medium-size reservoirs and nonrenewable groundwater in addition to precipitation to croplands which enabled the assessment of the origin of water producing major crops. Areas highly dependent on nonrenewable groundwater are detected in the Pakistan, Bangladesh, Western part of India, north and western parts of China, some regions in the Arabian Peninsula, and the western part of the United States through Mexico. Cumulative nonrenewable groundwater withdrawals estimated by the model are corresponding fairly well with the country statistics of total groundwater withdrawals. Ground water table depletions in large aquifers in US estimated by HiGW-MAT were compared with in-situ observational data, and the correspondences are very good. Mean global exploitation of ground water for 2000 estimated by HiGW-MAT is 360 km3/y as an excess of ground water withdrawal over natural recharge into aquifer. This unsustainable groundwater use, together with artificial reservoir water impoundment, climate-driven changes in

  3. Interannual water level variations in Lake Izabal, Guatemala, Centroamerica, using radar altimetry and its relationship with oceanographic features

    Science.gov (United States)

    Medina, C.; Gomez-Enri, J.; Alonso, J.; Villares, P.; Arias, M.; Catalan, M.; Labrador, I.

    2007-10-01

    It is well known that ocean-atmosphere dynamic affects the weather conditions over the continents and the ocean itself. The hydrologic cycle is driven by climatic parameters like precipitation, temperature, evaporation, winds and humidity. Hence, the river's water discharges and lake water level variations are impelled by climatic conditions also. Lake Izabal is the largest one in Guatemala; its main tributary is the Polochic River. Its level is related to the Polochic Rivers runoff and therefore to the precipitation/evaporation over its catchment area. The Lake Izabal water level fluctuations are driven by the annual cycle of rainy and dry seasons. In this study the ENVISAT RA-2 Geophysical Data Records orbits over the lake, coupled with in-situ measurements are used in order to determine and characterize the lake level fluctuations. The precipitation records over the lake's catchment area are also analyzed. In addition, some relationships of the lake level interannual variations with the climate indexes of Southern Oscillation Index SOI and the Tropical North Atlantic NATL were investigated. The main result is that the abrupt lake level rise in July 2006 is correlated to an abnormal precipitation in June 2006. Theoretically, this was forced by "La Nina" Southern Oscillation events during early 2006.

  4. Rapid fluctuations in extracellular brain glucose levels induced by natural arousing stimuli and intravenous cocaine: fueling the brain during neural activation

    Science.gov (United States)

    Lenoir, Magalie

    2012-01-01

    Glucose, a primary energetic substrate for neural activity, is continuously influenced by two opposing forces that tend to either decrease its extracellular levels due to enhanced utilization in neural cells or increase its levels due to entry from peripheral circulation via enhanced cerebral blood flow. How this balance is maintained under physiological conditions and changed during neural activation remains unclear. To clarify this issue, enzyme-based glucose sensors coupled with high-speed amperometry were used in freely moving rats to evaluate fluctuations in extracellular glucose levels induced by brief audio stimulus, tail pinch (TP), social interaction with another rat (SI), and intravenous cocaine (1 mg/kg). Measurements were performed in nucleus accumbens (NAcc) and substantia nigra pars reticulata (SNr), which drastically differ in neuronal activity. In NAcc, where most cells are powerfully excited after salient stimulation, glucose levels rapidly (latency 2–6 s) increased (30–70 μM or 6–14% over baseline) by all stimuli; the increase differed in magnitude and duration for each stimulus. In SNr, where most cells are transiently inhibited by salient stimuli, TP, SI, and cocaine induced a biphasic glucose response, with the initial decrease (−20–40 μM or 5–10% below baseline) followed by a reboundlike increase. The critical role of neuronal activity in mediating the initial glucose response was confirmed by monitoring glucose currents after local microinjections of glutamate (GLU) or procaine (PRO). While intra-NAcc injection of GLU transiently increased glucose levels in this structure, intra-SNr PRO injection resulted in rapid, transient decreases in SNr glucose. Therefore, extracellular glucose levels in the brain change very rapidly after physiological and pharmacological stimulation, the response is structure specific, and the pattern of neuronal activity appears to be a critical factor determining direction and magnitude of physiological

  5. Holocene palaeoclimate and sea level fluctuation recorded from the coastal Barker Swamp, Rottnest Island, south-western Western Australia

    Science.gov (United States)

    Gouramanis, C.; Dodson, J.; Wilkins, D.; De Deckker, P.; Chase, B. M.

    2012-10-01

    The Holocene palaeoclimatic history of south-western Western Australia (SWWA) has received little attention compared to south-eastern Australia, and this has resulted in conflicting views over the impact of climate variability in the region. We present here a well-dated, high-resolution record from two overlapping sediment cores obtained from the centre of Barker Swamp, Rottnest Island, offshore Perth. The records span the last 8.7 ka, with the main lacustrine phase occurring after 7.4 ka. This site preserves both pollen and several ostracod taxa. The pollen record suggests a long-term shift from the early-mid Holocene to the late Holocene to drier conditions with less shrubland and more low-ground cover and less fire activity. A salinity transfer function was developed from ostracod faunal assemblage data and trace metal ratios (Mg/Ca, Sr/Ca and Na/Ca) and stable isotopes (δ18O and δ13C) analysed on selected ostracod valves. These provide a detailed history of evaporation/precipitation (E/P) differences that clearly shows that the SWWA region was subjected to significant climatic shifts over the last 7.4 ka, with a broad shift towards increased aridity after 5 ka. The swamp ranged from fresh to saline as recorded in the ostracod valve chemistry and the independently-derived salinity transfer function. The ostracod record also indicates that a sea-level highstand occurred between ca. 4.5 and 4.3 ka, with probable step-wise increases at 6.75, 6.2, and 5.6 ka, with the last vestiges of salt water intrusion at ca. 1 ka. After about 2.3 ka, the fresh, groundwater lens that underlies the western portion of the island intersected the swamp depression, influencing the hydrology of the swamp. The broad climatic changes recorded in Barker Swamp are also compared with data from southern South Africa, and it is suggested that the Southern Annular Mode appears to have been the dominant driver in the climate of these regions and that the Indian Ocean Dipole is of little

  6. Impacts of Water Levels on Breeding Canada Geese and the Methodology for Mitigation and Enhancement in the Flathead Drainage, 1983 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Ball, I. Joseph

    1984-01-01

    The lower Flathead River Canada goose study was initiated to determine goose population trends and the effects of water level fluctuations on Canada goose nest and brood habitat, as a result of releases from Kerr Dam. This report presents data collected during the 1983 field season (15 February to 30 September, 1983) as part of an ongoing project. (DT)

  7. Ground-water discharge determined from measurements of evapotranspiration, other available hydrologic components, and shallow water-level changes, Oasis Valley, Nye County, Nevada

    Science.gov (United States)

    Reiner, S.R.; Laczniak, R.J.; DeMeo, G.A.; Smith, Jody L.; Elliott, P.E.; Nylund, W.E.; Fridrich, C.J.

    2002-01-01

    component of 0.5 foot, is estimated to be about 6,000 acre-feet. Annual subsurface outflow from Oasis Valley into the Amargosa Desert is estimated to be between 30 and 130 acre-feet. Estimates of total annual ground-water withdrawal from Oasis Valley by municipal and non-municipal users in 1996 and 1999 are 440 acre-feet and 210 acre-feet, respectively. Based on these values, natural annual ground-water discharge from Oasis Valley is about 6,100 acre-feet. Total annual discharge was 6,500 acre-ft in 1996 and 6,300 acre-ft in 1999. This quantity of natural ground-water discharge from Oasis Valley exceeds the previous estimate made in 1962 by a factor of about 2.5. Water levels were measured in Oasis Valley to gain additional insight into the ET process. In shallow wells, water levels showed annual fluctuations as large as 7 feet and daily fluctuations as large as 0.2 foot. These fluctuations may be attributed to water loss associated with evapotranspiration. In shallow wells affected by ET, annual minimum depths to water generally occurred in winter or early spring shortly after daily ET reached minimum rates. Annual maximum depths to water generally occurred in late summer or fall shortly after daily ET reached maximum rates. The magnitude of daily water-level fluctuations generally increased as ET increased and decreased as depth to water increased.

  8. Image-based Water Level Measurement Method under Stained Ruler

    Institute of Scientific and Technical Information of China (English)

    Jae-do KIM; Young-joon HAN; Hern-soo HAHN

    2010-01-01

    This paper proposes the water level measuring method based on the image,while the ruler used to indicate the water level is stained.The contamination of the ruler weakens or eliminates many features which are required for the image processing.However,the feature of the color difference between the ruler and the water surface are firmer on the environmental change compare to the other features.As the color differences are embossed,only the region of the ruler is limited to eliminate the noise,and the average image is produced by using several continuous frames.A histogram is then produced based on the height axis of the produced intensity average image.Local peaks and local valleys are detected,and the section between the peak and valley which have the greatest change is looked for.The valley point at this very moment is used to detect the water level.The detected water level is then converted to the actual water level by using the mapping table.The proposed method is compared to the ultrasonic based method to evaluate its accuracy and efficiency on the various contaminated environments.

  9. Fluctuating sea levels off Bombay (India) between 14,500 and 10,000 years before present

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Hashimi, N.H.; Menezes, E.T.; Wagh, A.B.

    of deposition shows that sea level had transgressed considerably prior to 10,000 years before present (super(14) C age of the surface sediment). By comparison with global events, we infer that the sea level was at 101.5 m below the present level at about 14...

  10. Analysis of the causes of price fluctuations of dairy products at individual levels of the product vertica

    Directory of Open Access Journals (Sweden)

    Z. Gebeltová

    2010-09-01

    Full Text Available The paper analyzes the reasons for the prices of milk and milk products in the Czech Republic for the period 2008 – 2009. In January 2008, the purchase price of raw milk was 10.08 CZK/l, and in the subsequent period it began to decline. At the end of 2008, the price was more than 3 crowns lower, and still the decrease continued. The research determined that the essential reason for the price fluctuations is the impact of the economic crisis. A substantial portion of the article was devoted to analyzing the behavior of supermarket chains toward their suppliers. It was discovered that even here there is a lot of room for the creation of pricing policy. Margin trading networks up to 25% of the delivered goods. Price negotiations affect the position papers in the manufacturing vertical. The power of suppliers and processors is based on the establishment of a strong integration unit. In the conclusion the author discusses possible future developments in price, sales policy, and the self-sufficiency of milk production in the Czech Republic. The paper was processed within the framework of the Research Project of MSM 6046070906 "The economics of Czech agricultural resources and their effective use within the framework of multifunctional agri-food systems".

  11. Radar Based Flow and Water Level Forecasting in Sewer Systems

    DEFF Research Database (Denmark)

    Thorndahl, Søren; Rasmussen, Michael R.; Grum, M.;

    2009-01-01

    This paper describes the first radar based forecast of flow and/or water level in sewer systems in Denmark. The rainfall is successfully forecasted with a lead time of 1-2 hours, and flow/levels are forecasted an additional ½-1½ hours using models describing the behaviour of the sewer system. Both...

  12. Theoretic analysis on phase delay phenomena of well water level tide in the double medium aquifer model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A model of double medium aquifer is briefly introduced in this paper, a partial differential equation about seepage motion derived by the tidal stress in the model layer is deduced. Compared this equation with Boulton equation used in the unconfined aquifer, a new lagging supply water term is obtained, which establish the physical basis for interpreting the phase delay phenomena of well water level caused by the solid tide. By analyzing the partial dif-ferential equation, it is found that this lagging supply term is related with the fluctuation of tide occurred in the deep aquifer.

  13. Decadal fluctuations in North Atlantic water inflow in the North Sea between 1958-2003: impacts on temperature and phytoplankton populations

    Directory of Open Access Journals (Sweden)

    Martin J. Attrill

    2008-03-01

    Full Text Available The circulation of Atlantic water along the European continental slope, in particular the inflow into the North Sea, influences North Sea water characteristics with consequent changes in the environment affecting plankton community dynamics. The long-term effect of fluctuating oceanographic conditions on the North Sea pelagic ecosystem is assessed. It is shown that (i there are similar regime shifts in the inflow through the northern North Sea and in Sea Surface Temperature, (ii long-term phytoplankton trends are influenced by the inflow only in some North Sea regions, and (iii the spatial variability in chemicophysical and biological parameters highlight the influence of smaller scale processes.

  14. Relation of drainage problems to high ground-water levels, Coconut Grove area, Oahu, Hawaii

    Science.gov (United States)

    Swain, L.A.; Huxel, C.J., Jr.

    1971-01-01

    Purpose and Scope In 1969, hydrologic data-collection sites were established in and around the Coconut Grove area for the purpose of measuring directly the relationship between rainfall, runoff, ground-water levels, the level of water in Kawainui Swamp and the canals, and tidal fluctuations. The primary objective was to identify the causes of the occurrence and persistence of flooding and to gain data on which to base recommendations for remedial action. The scope of the study included establishing and operating flow and stage-recording gages on the Swamp, Kawainui Canal, and the inner canal; periodic and repeated measurements of ground-water level in test borings throughout the residential area; collection and analysis of soil and construction borings made for engineering purposes; the assembly and analysis of all available data relating surface and subsurface flow conditions, and the development of conclusions as to the causes and means to alleviate the flooding. This report summarizes the information collected from October 1969 to June 1971, includes analysis of the data, and discusses the probable causes of flooding.

  15. Paleocommunity Replacements of Benthic Brachiopod in the Middle-Upper Devonian in the Longmenshan Area, Southwestern China: Responses to Sea Level Fluctuations

    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanren; LI Xianghui

    2005-01-01

    Twelve paleocommunities dominated by benthic brachiopod are recognized in the Givetian-Frasnian stages of the Devonian in the Longmenshan area, southwestern China, in which two kinds of brachiopod community replacement are classified. One is the abrupt replacement, represented by abrupt alternation between the Leiorhynchus community and Zhonghuacoelia-Striatopugnax community in the Frasnian Tuqiaozi Formation. The other is the gradual one, developed in the Givetian Guanwushan Formation, which had been completed by the shift of the Independatrypa lemma-Uncinulus heterocostellis-Emanuella takwanensis community via the Sinospongophyllum irregulare-Pseudomicroplasma fongi community to the Clathrocoilona spissa-Hexagonaria composite reef community. According to analyses of the paleocommunities, either the abrupt or gradual paleocommunity replacement of the Middle-Upper Devonian in the Longmenshan area is suggested as a response to the 5th-order sea level fluctuation due to the replacements of the paleocommunities in a tracts-system of depositional sequence. It is supposed that changes of paleocommunity diversity,one of the results of paleocommunity replacement, are depended on the range and magnitude of sea level fluctuation, but there is not a linear relationship between them. Furthermore, a suggestion is proposed that the concept of paleocommunity succession seem to be abandoned in the paleocommunity analysis because it almost never be practiced to recover the information of community succession in the geological record at present.

  16. Water uptake strategies of maize under varying levels of water stress

    Science.gov (United States)

    van der Ploeg, M.; Gooren, H. P. A.; Bakker, G.; de Rooij, G. H.

    2009-04-01

    More frequent and intense droughts due to global climate change, together with an increasing agricultural water use emphasize the importance of understanding root water uptake under water-stressed conditions. While root water uptake is driven by potential gradients, measurement of soil water potentials was limited by the measurement range of water-filled tensiometers (-0.085 MPa). A recently developed polymer tensiometer (POT) can measure soil water potentials down to -1.6 MPa. Monitoring low soil water potentials in the presence of root water uptake may help gain knowledge of a plant's strategy to cope with water stress, and allows improved determination of local water stress levels in experiments. To investigate plant strategies that cope with water stress, soil water potentials were measured in the vicinity of maize roots in three lysimeters. The lysimeters received different irrigation amounts: an optimal irrigation gift (-0.05 < p < -0.02 MPa) and minimized irrigation to create moderate (minimum p = -0.45 MPa) and severe (minimum p = -0.80 MPa) water stress. Measured soil water potentials showed that the water stressed plants started to take up water from deeper soil layers, and continued to take up water under very dry conditions. This research was funded by the Dutch Technology Foundation (STW).

  17. WATER-LEVEL MONITOR FOR BOREWELL AND WATER TANK BASED ON GSM

    Directory of Open Access Journals (Sweden)

    R.Ramani

    2012-10-01

    Full Text Available Now a days, home automation & remote control and monitoring systems have seen a rapid growth in terms of technology. Apparently there is no early warning system to monitor the tank water level and bore well water level when it has reached the critical level. In this paper we have provided water level monitoring in the tank as well as in the bore well. If the water level in a bore well drops below the threshold level for pumping its pump motor may get air locked or more burn out due to dry running. It is awkward for farmers to walk all the way to their fields at night just to switch the pump motor off. Besides, he may never get to identify the problem. This problem can be solved by using this GSM based system that will automatically make a call to the user mobile phone, when the water Level in the bore well drops threshold below or rises to the threshold level for pumping. The user can also remotely switch on or off the pump motor by sending a SMS from his mobile phone. The system is simple, reliable, portable and affordable. We proposed the work in which, Whenever water level in the tankdrops below the required level the system try to fill the tank by switching on the bore well motor to pump the water into the tank It is must to have enough water in the bore well to avoid the formation of air gap or empty running of bore well motor. High precision water level sensor is used to identify the reference water level to activate and deactivate the motor and system properly by interfacing the sensor devices into the well definedembedded system.

  18. Carbon and strontium isotope variations and responses tosea-level fluctuations in the Ordovician of the Tarim Basin

    Institute of Scientific and Technical Information of China (English)

    JIANG; Maosheng

    2001-01-01

    [1]Arthur, M. A., The carbon cycle-controls of atmospheric CO2 and climate in the geologic past, in Climate in Earth History (eds., Berger, W. M., Crowell, J. C), Washington D C: U. S. National Academy Press, 1982, 55-67.[2]Kroopnick, P. M., Margolis, M. V., Wong, C. S., δ18C variations in marine carbonate sediments as indicators of the CO2 balance between atmosphere and ocean, in The Fate of Fossil Fuel CO2 in the Ocean (eds., Anderson, N. R., Malahoff. A.),New York: Plenum Press, 1977, 295-321.[3]Veizer, J., Fritz, P., Jones, B., Geochemistry of brachiopods: Oxygen and carbon isotopic records of Paleozoic oceans,Geochim. Cosmochim. Acta, 1986, 50: 1679- 1696.[4]Wadleigh, M. A., Veizer, J., 18O/16O and 13C/12C in Lower Paleozoic articulate brachiopods: Implications for the isotopic composition seawater, Geochim. Cosmochim. Acta, 1992, 56:431-443.[5]Goldberg, E. D., Minor elements in sea water, in Chemical Oceanography (eds., Riley, J. P., Skirrow, G.), Vol. l, New York: Academic Press, 1986.[6]Fanre, G., Principles ofIsotope Geology, New York: Wiley, 1986, 1 -589.[7]Ebneth, S., Diener, A., Buhl, D. et al., Strontium isotope systematics of conodonts: Middle Devonian, Eifel Mts. Germany,Paleogeogr. Paleoclimatol. Paleoecol, 1996, 119:201 - 214.[8]Martin, E. E., Macdougall, J. D., Sr and Nd isotopes at Permian / Triassic boundary: A record of climate change, Chem.Geol.. 1995. 125: 73-79.[9]Jones. C. E.. Jenkyns, H. C., Hesselbo, S. P., Strotium isotopic variations in Jurassic and Cretaceous seawater, Geochemica et Cosmochemica Acta. 1994, 58:3061 - 3074.[10]McArthur. J. M., Kennedy, W. J., Chen, M. et al., Staontium isotope stratigraphy for Late Cretaceous time: Drect numerical clibration of the Sr curve based on the U.S. western interior, Paleogeogr. Paleoclimatol. Paleoecol., 1994, 108:95-119.[11]McArthur, J. M., Thirlwall, M. F., Gale, A. S. et al., Strotium isotope stratigraphy for the Late Cretaceous: A new curve

  19. Poster abstract: Water level estimation in urban ultrasonic/passive infrared flash flood sensor networks using supervised learning

    KAUST Repository

    Mousa, Mustafa

    2014-04-01

    This article describes a machine learning approach to water level estimation in a dual ultrasonic/passive infrared urban flood sensor system. We first show that an ultrasonic rangefinder alone is unable to accurately measure the level of water on a road due to thermal effects. Using additional passive infrared sensors, we show that ground temperature and local sensor temperature measurements are sufficient to correct the rangefinder readings and improve the flood detection performance. Since floods occur very rarely, we use a supervised learning approach to estimate the correction to the ultrasonic rangefinder caused by temperature fluctuations. Preliminary data shows that water level can be estimated with an absolute error of less than 2 cm. © 2014 IEEE.

  20. Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold: Part II. Effects of Mold Oscillation and Mold Level Fluctuation

    Science.gov (United States)

    Zhang, Haihui; Wang, Wanlin

    2016-04-01

    The surface quality of the continuous casting strands is closely related to the initial solidification of liquid steel in the vicinity of the mold meniscus, and thus the clear understanding of the behavior of molten steel initial solidification would be of great importance for the control of the quality of final slab. With the development of the mold simulator techniques, the complex interrelationship between the solidified shell surface profile, heat flux, shell thickness, mold level fluctuation, and the infiltrated slag film was well illustrated in our previous study. As the second part, this article investigated the effect of the mold oscillation frequency, stroke, and mold level fluctuation on the initial solidification of the molten steel through the conduction of five different experiments. Results suggested that in the case of the stable mold level, the oscillation marks (OMs) exhibit equally spaced horizon depressions on the shell surface, where the heat flux at the meniscus area raises rapidly during negative strip time (NST) period and the presence of each OMs on the shell surface is corresponding to a peak value of the heat flux variation rate. Otherwise, the shell surface is poorly defined by the existence of wave-type defects, such as ripples or deep depressions, and the heat flux variation is irregular during NST period. The rising of the mold level leads to the longer-pitch and deeper OMs formation; conversely, the falling of mold level introduces shorter-pitch and shallower OMs. With the increase of the mold oscillation frequency, the average value of the low-frequency heat flux at the meniscus increases; however, it decreases when the mold oscillation stroke increases. Additionally, the variation amplitude of the high-frequency temperature and the high-frequency heat flux decreases with the increase of the oscillation frequency and the reduction of the oscillation stroke.

  1. Diagenesis in limestone-dolostone successions after 1 million years of rapid sea-level fluctuations: A case study from Grand Cayman, British West Indies

    Science.gov (United States)

    Ren, Min; Jones, Brian

    2016-08-01

    Meteoric diagenesis in young marine carbonate sediments has commonly been linked to fluctuations in Quaternary glacio-eustatic sea levels. The extent to which these sea-level changes are recorded in these carbonate successions, however, remains questionable. This is amply demonstrated by the diagenetic record found in the limestones and dolostones of the Cayman Formation (Miocene) on the Cayman Islands. On the eastern part of Grand Cayman, dolomitization that ceased by 1 million years ago created an architecture whereby the limestones in the central part of the island were surrounded by dolostones in coastal areas of the island. Since then, the upper 90 m of the Cayman Formation has been repeatedly cycled through many different marine and meteoric diagenetic zones as large, rapid eustatic oscillations in sea level affected the island. The records of these diagenetic cycles in the dolostones and limestones are, however, different and impossible to match to the cyclic changes in sea level. In the peripheral dolostones, post-dolomitization diagenetic features are sparse. In contrast, the limestones in the interior of the island exhibit a wider variety of meteoric diagenetic features, including extensive dissolution and calcite cementation. The dolostones have low porosity (limestones are characterized by high porosity (up to 50%), especially in the lower and middle parts of the studied limestone succession. The different phases of diagenesis found in the limestones, however, cannot be specifically matched to any sea-level fluctuations that have affected these successions. This issue is further exemplified by the fact that that the last marine transgression over the last ~ 16,000 years ago appears to have left no tangible record. The analysis of this succession clearly demonstrates that not all diagenetic regimes will be recorded in the fabrics of limestones or dolostones.

  2. Mixing height over water and its role on the correlation between temperature and humidity fluctuations in the unstable surface layer

    DEFF Research Database (Denmark)

    Sempreviva, A.M.; Gryning, Sven-Erik

    2000-01-01

    investigated the influence of the mixed-layer height on the correlation coefficient RqT between temperature and humidity fluctuations using the values obtained with the model. We found that the evolution of RqT follows the evolution of the mixing height. An empirical model linking the surface values of Rq...

  3. Effect of fluctuating high blood glucose level on vascular endothelial function%波动性高血糖对血管内皮功能的影响

    Institute of Scientific and Technical Information of China (English)

    李雷; 杨荣礼; 吕丽丽; 李平静; 王春晴; 杨煜

    2012-01-01

    Objective To observe the effect of fluctuating high blood glucose level on vascular endothelial function and its mechanism underlying atherosclerosis. Methods Seventy-two newly diagnosed type 2 diabetic mellitus patients were divided into persistent high blood glucose level group(n=33) and fluctuating high blood glucose level group(?? = 39) acording to their dynamic blood glucose monitoring. Their brachial endothelium-dependent dilation(EDD) ,carotid IMT,and levels of lipid, fasting plasma glucose, fasting insulin, postprandial 2 h plasma glucose ( 2hPG ), postprandial 2 h insulin(2hINS) , hs-CRP, vWF,and microalbuminuria(MAU) were measured. Results The postprandial 2hPG and 2hINS,hs-CRP,vWF,MAU and IMT levels were significantly higher(P<0. 05,P<0. 01) while the brachial EDD was significantly lower(6. 61%+0. 79% vs 5. 21% + 0. 88% , P<0. 01) in fluctuating high blood glucose level group than in persistent high blood glucose level group. Conclusion Fluctuating high blood glucose level is more harmful than persistent high blood glucose level to vascular endothelial function,which may be related with the postprandial hyperglycemia, insulin resistance and increasing inflammatory factors.%目的 观察波动性高血糖对血管内皮功能的影响,探讨其致动脉粥样硬化的机制.方法 选择新诊断的2型糖尿病患者72例,根据动态血糖监测结果分持续性高血糖组33例和波动性高血糖组39例,检测患者的肱动脉内皮依赖性舒张功能(EDD)及颈动脉内膜中层厚度(IMT)、血脂、空腹血糖、空腹胰岛素、餐后2h血糖(2hPG)/及餐后2h胰岛素(2hINS)、高敏C反应蛋白(hs-CRP)、血管性假血友病因子(vWF)及尿微量白蛋白(MAU).结果 与持续性高血糖组比较,波动性高血糖组的2hPG、2hINS、hs-CRP、Vwf、MAU及IMT明显升高(P<0.05,P<0.01),肱动脉EDD明显降低[(6.61±0.79)%vs (5.21±0.88)%,P<0.01].结论 波动性高血糖较持续性高血糖对血管内皮功能危害更

  4. Effects of Water Levels on Productivity of Canada Geese in the Northern Flathead Valley, 1984 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Daniel

    1985-02-01

    Operation of Hungry Horse Dam on the South Fork Flathead River causes sporadic level fluctuations along the main stem Flathead River. Seasonal water level fluctuations and substantial habitat losses have occurred as a result of construction and operation of Kerr Dam, which regulates Flathead Lake. These fluctuations may impact goose populations through flooding or erosion of nesting and brood-rearing habitats, and increased susceptibility of nests and young to predation. The number, location, and success of goose nests were determined through pair surveys and nest searches. Counts of indicated pairs suggest there were 73-125 occupied nests in the study area; 44 were located in 1984. Twenty were island ground nests, 19 were tree nests, and 5 were on man-made structures. Hatching success was 76 percent. Sixty-one percent of all nests were in deciduous forest habitat; 87 percent were on riparian bench or island landforms. Seventy-four percent of all nests were within 5 m of the seasonal high water mark (HWM) and 85 percent of ground nests were 1 m or less above the HWM. Production, habitat use, and distribution of broods were documented through aerial, boat, ground, and observation tower surveys. 28 refs., 10 figs., 4 tabs.

  5. Response of bacterial community structure to seasonal fluctuation and anthropogenic pollution on coastal water of Alang-Sosiya ship breaking yard, Bhavnagar, India.

    Science.gov (United States)

    Patel, Vilas; Munot, Hitendra; Shouche, Yogesh S; Madamwar, Datta

    2014-06-01

    Bacterial community structure was analyzed from coastal water of Alang-Sosiya ship breaking yard (ASSBY), world's largest ship breaking yard, near Bhavnagar, using 16S rRNA gene sequencing (cultured dependent and culture independent). In clone libraries, total 2324 clones were retrieved from seven samples (coastal water of ASSBY for three seasons along with one pristine coastal water) which were grouped in 525 operational taxonomic units. Proteobacteria was found to be dominant in all samples. In pristine samples, Gammaproteobacteria was found to be dominant, whereas in polluted samples dominancy of Gammaproteobacteria has shifted to Betaproteobacteria and Epsilonproteobacteria. Richness and diversity indices also indicated that bacterial community in pristine sample was the most diverse followed by summer, monsoon and winter samples. To the best of knowledge, this is the first study describing bacterial community structure from coastal water of ASSBY, and it suggests that seasonal fluctuation and anthropogenic pollutions alters the bacterial community structure.

  6. Water Quality and Hydrology of Silver Lake, Barron County, Wisconsin, With Special Emphasis on Responses of a Terminal Lake to Changes in Phosphorus Loading and Water Level

    Science.gov (United States)

    Robertson, Dale M.; Rose, William J.; Fitzpatrick, Faith A.

    2009-01-01

    nearshore runoff and 22 percent from atmospheric deposition. Because Silver Lake is hydraulically mounded above the local groundwater system, little or no input of phosphorus to the lake is from groundwater and septic systems. Silver Lake had previously been incorrectly described as a groundwater flowthrough lake. Phosphorus budgets were constructed for a series of dry years (low water levels) and a series of wet years (high water levels). About 6 times more phosphorus was input to the lake during wet years with high water levels than during the dry years. Phosphorus from erosion represented 13-20 percent of the phosphorus input during years with very high water levels. Results from the Canfield and Bachman eutrophication model and Carlson trophic state index equations demonstrated that water quality in Silver Lake directly responds to changes in external phosphorus input, with the percent change in chlorophyll a being about 80 percent of the percent change in total phosphorus input and the change in Secchi depth and total phosphorus concentrations being about 40 and 50 percent of the percent change in input, respectively. Therefore, changes in phosphorus input should impact water quality. Specific scenarios were simulated with the models to describe the effects of natural (climate-driven) and anthropogenic (human-induced) changes. Results of these scenarios demonstrated that several years of above-normal precipitation cause sustained high water levels and a degradation in water quality, part of which is due to erosion of the shoreline. Results also demonstrated that 1) changes in tributary and nearshore runoff have a dramatic effect on lake-water quality, 2) diverting water into the lake to increase the water level is expected to degrade the water quality, and 3) removal of water to decrease the water level of the lake is expected to have little effect on water quality. Fluctuations in water levels since 1967, when records began for the lake, are representative

  7. AUTOMATED WATER LEVEL MEASUREMENTS IN SMALL-DIAMETER AQUIFER TUBES

    Energy Technology Data Exchange (ETDEWEB)

    PETERSEN SW; EDRINGTON RS; MAHOOD RO; VANMIDDLESWORTH PE

    2011-01-14

    Groundwater contaminated with hexavalent chromium, strontium-90, and uranium discharges into the Columbia River along approximately 16 km (10 mi) of the shoreline. Various treatment systems have and will continue to be implemented to eliminate the impact of Hanford Site contamination to the river. To optimize the various remediation strategies, it is important to understand interactions between groundwater and the surface water of the Columbia River. An automated system to record water levels in aquifer sampling tubes installed in the hyporheic zone was designed and tested to (1) gain a more complete understanding of groundwater/river water interactions based on gaining and losing conditions ofthe Columbia River, (2) record and interpret data for consistent and defensible groundwater/surface water conceptual models that may be used to better predict subsurface contaminant fate and transport, and (3) evaluate the hydrodynamic influence of extraction wells in an expanded pump-and-treat system to optimize the treatment system. A system to measure water levels in small-diameter aquifer tubes was designed and tested in the laboratory and field. The system was configured to allow manual measurements to periodically calibrate the instrument and to permit aquifer tube sampling without removing the transducer tube. Manual measurements were collected with an e-tape designed and fabricated especially for this test. Results indicate that the transducer system accurately records groundwater levels in aquifer tubes. These data are being used to refine the conceptual and numeric models to better understand interactions in the hyporheic zone of the Columbia River and the adjacent river water and groundwater, and changes in hydrochemistry relative to groundwater flux as river water recharges the aquifer and then drains back out in response to changes in the river level.

  8. Politics of innovation in multi-level water governance systems

    Science.gov (United States)

    Daniell, Katherine A.; Coombes, Peter J.; White, Ian

    2014-11-01

    Innovations are being proposed in many countries in order to support change towards more sustainable and water secure futures. However, the extent to which they can be implemented is subject to complex politics and powerful coalitions across multi-level governance systems and scales of interest. Exactly how innovation uptake can be best facilitated or blocked in these complex systems is thus a matter of important practical and research interest in water cycle management. From intervention research studies in Australia, China and Bulgaria, this paper seeks to describe and analyse the behind-the-scenes struggles and coalition-building that occurs between water utility providers, private companies, experts, communities and all levels of government in an effort to support or block specific innovations. The research findings suggest that in order to ensure successful passage of the proposed innovations, champions for it are required from at least two administrative levels, including one with innovation implementation capacity, as part of a larger supportive coalition. Higher governance levels can play an important enabling role in facilitating the passage of certain types of innovations that may be in competition with currently entrenched systems of water management. Due to a range of natural biases, experts on certain innovations and disciplines may form part of supporting or blocking coalitions but their evaluations of worth for water system sustainability and security are likely to be subject to competing claims based on different values and expertise, so may not necessarily be of use in resolving questions of "best courses of action". This remains a political values-based decision to be negotiated through the receiving multi-level water governance system.

  9. Water-quality and ground-water-level data, Bernalillo County, central New Mexico, 1995

    Science.gov (United States)

    Rankin, D.R.

    1996-01-01

    Water-quality and ground-water-level data were collected in two areas of eastern Bernalillo County in central New Mexico between March and July of 1995. Fifty-one wells, two springs, and the Ojo Grande Acequia in the east mountain area of Bernalillo County and nine wells in the northeast area of the city of Albuquerque were sampled. The water samples were analyzed for selected nutrient species; total organic carbon; major dissolved constituents; dissolved arsenic, boron, iron, and manganese; and methylene blue active substances. Analytical results were used to compute hardness, sodium adsorption ratio, and dissolved solids. Specific conductance, pH, temperature, and alkalinity were measured in the field at the time of sample collection. Ground- water-level and well-depth measurements were made at the time of sample collection when possible. Water-quality data, ground- water-level data, and well-depth data are presented in tabular form.

  10. Interspecific hybridization does not affect the level of fluctuating asymmetry (FA) in the Drosophila bipectinata species complex.

    Science.gov (United States)

    Banerjee, Parul; Singh, B N

    2015-08-01

    The Drosophila bipectinata species complex comprises of four very closely related species namely D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae. It was found that irrespective of the evolutionary divergence among the species, FA which is reflective of the developmental precision remains nearly same in four species. During the present study, the level of FA in different morphological traits was studied in interspecific hybrids and compared with that of parental species with the view that it would throw light on the degree of divergence between the parental species. If they have not diverged much, the interspecific hybrids may have a similar FA level, incompatibilities between their genomes being negligible. On the other hand, if there is substantial divergence, the level of FA may be higher due to incompatibility between the genomes of the parental species. The morphological traits taken were sternopleural bristle number and wing length in both males and females and ovariole number and sex-comb tooth number in females and males respectively. However, except in a few cases, we could not detect any significant differences in the level of FA in hybrids as compared to pure species. On the other hand, a number of abnormalities like poor viability, dystrophied ovaries, asymmetrical eyes etc., could be detected in hybrids from crosses involving D. pseudoananassae as one of the parents. Therefore, we conclude that specific developmental pathways are more susceptible to developmental disturbances due to genomic incompatibilities than the large complex system bringing about developmental stability.

  11. Influence of nutrient level on methylmercury content in water spinach.

    Science.gov (United States)

    Greger, Maria; Dabrowska, Beata

    2010-08-01

    Widely consumed vegetables are often cultivated in sewage waters with high nutrient levels. They can contain high levels of methylmercury (MeHg), because they can form MeHg from inorganic Hg in their young shoots. We determined whether the MeHg uptake and the MeHg formation in the shoots of water spinach (Ipomoea aquatica) were affected by the presence of a high nutrient level in the growth medium. Water spinach shoots were rooted and pretreated in growth medium containing 7% (low) or 70% (high) Hoagland nutrient solution; thereafter, the plants were treated with either 0.02 microM MeHg or 0.2 microM HgCl2 for 3 d. Half the plants were then analyzed for total Hg and MeHg. The remaining plants were transferred to mercury-free medium with low or high nutrient levels and posttreated for 3 days before analysis of total Hg and MeHg in order to measure MeHg formation in the absence of external Hg. The results indicate that nutrient level did not influence MeHg uptake, but that a high nutrient level reduced the distribution of MeHg to the shoots 2.7-fold versus low nutrient level. After treatment with HgCl2, MeHg was found in roots and new shoots but not in old shoots. The MeHg:total-Hg ratio was higher in new shoots than in roots, being 13 times higher at high versus low nutrient levels. Thus, MeHg formation was the same in new shoots independent of inorganic Hg concentration, since the total Hg level decreased at a high nutrient level.

  12. Low-level measurements of tritium in water

    International Nuclear Information System (INIS)

    Using a liquid scintillation counter, an experimental procedure for measuring low-level activity concentrations of tritium in environmental water has been developed by our laboratory, using the electrolytic tritium enrichment. Additionally, some quality tests were applied in order to assure the goodness of the method. Well-known water samples collected in the Tagus River (West of Spain) and the Danube River (Bulgaria), both affected by nuclear plant releases, were analysed and results were compared to previous data. The analytical procedure was applied to drinking water samples from the public water supply of Seville and mineral waters from different springs in Spain in order to characterize its origin. Due to the very low levels of tritium in the analysed samples, some results were reported as lower than the minimum detectable activity concentration (MDA). However, the count rate of these measurements was over the background count rate of LS counter in all the cases. For that reason, an exhaustive discussion about the meaning of the MDA, using an experimental essay, was made in order to establish a rigorous criterion that leads to a reliable value in the case of low-level measurements

  13. On the derivation of specific yield and soil water retention characteristics in peatlands from rainfall, microrelief and water level data - Theory and Practice

    Science.gov (United States)

    Dettmann, Ullrich; Bechtold, Michel

    2016-04-01

    Water level depth is one of the crucial state variables controlling the biogeochemical processes in peatlands. For flat soil surfaces, water level depth dynamics as response to boundary fluxes are primarily controlled by the water retention characteristics of the soil in and above the range of the water level fluctuations. For changing water levels, the difference of the integrals of two soil moisture profiles (∆Asoil), of a lower and a upper water level, is equal to the amount of water received or released by the soil. Dividing ∆Asoil by the water level change, results into a variable that is known as specific yield (Sy). For water level changes approaching the soil surface, changes in soil water storage are small due to the thin unsaturated zone that remains. Consequentially, Sy values approach zero with an abrupt transition to 1 in case of inundation. However, on contrary, observed water level rises due to precipitation events at various locations showed increasing Sy values for water level changes at shallow depths (Sy = precipitation/water level change; Logsdon et al., 2010). The increase of Sy values can be attributed in large parts to the influence of the microrelief on water level changes in these wet landscapes that are characterized by a mosaic of inundated and non-inundated areas. Consequentially, water level changes are dampened by partial inundation. In this situation, total Sy is composed of a spatially-integrated below ground and above ground contribution. We provide a general one-dimensional expression that correctly represents the effect of a microrelief on the total Sy. The one-dimensional expression can be applied for any soil hydraulic parameterizations and soil surface elevation frequency distributions. We demonstrate that Sy is influenced by the microrelief not only when surface storage directly contributes to Sy by (partial) inundation but also when water levels are lower than the minimum surface elevation. With the derived one

  14. Precision Monitoring of Water Level in a Salt Marsh with Low Cost Tilt Loggers

    Science.gov (United States)

    Sheremet, Vitalii A.; Mora, Jordan W.

    2016-04-01

    Several salt pannes and pools in the Sage Lot tidal marsh of Waquoit Bay system, MA were instrumented with newly developed Arm-and-Float water level gauges (utilizing accelerometer tilt logger) permitting to record water level fluctuations with accuracy of 1 mm and submillimeter resolution. The methodology of the instrument calibration, deployment, and elevation control are described. The instrument performance was evaluated. Several month long deployments allowed us to analyze the marsh flooding and draining processes, study differences among the salt pannes. The open channel flow flooding-draining mechanism and slower seepage were distinguished. From the drain curve the seepage rate can be quantified. The seepage rate remains approximately constant for all flooding draining episodes, but varies from panne to panne depending on bottom type and location. Seasonal differences due to the growth of vegetation are also recorded. The analysis of rain events allows us to estimate the catch area of subbasins in the marsh. The implication for marsh ecology and marsh accretion are discussed. The gradual sea level rise coupled with monthly tidal datum variability and storm surges result in migration and development of a salt marsh. The newly developed low cost instrumentation allows us to record and analyze these changes and may provide guidance for the ecological management.

  15. Stationary flow solution for water levels in open channels

    NARCIS (Netherlands)

    Opheusden, van J.H.J.; Molenaar, J.; Beltman, W.H.J.; Adriaanse, P.I.

    2010-01-01

    We study stationary flow in open discharge channels. A model is derived from basic principles, which is solved numerically for the water level and discharge as a function of position along the channel. The model describes the effect of external inflow from fields adjacent to the channel. Several sce

  16. CAN FLUORIDATION AFFECT WATER LEAD LEVELS AND LEAD NEUROTOXICITY?

    Science.gov (United States)

    Recent reports have attempted to show that certain approaches to fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of nexafluo...

  17. Effects of Water Levels on Productivity of Canada Geese in the Northern Flathead Valley, 1985 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Daniel

    1986-04-01

    Operation of Hungry Horse Dam on the South Fork Flathead River causes sporadic water level fluctuations along the main stem Flathead River. Changes in chronology of seasonal water level fluctuations and substantial habitat losses have occurred as a result of construction and operation of Kerr Dam, which regulates Flathead Lake. These fluctuations may impact goose populations through flooding and erosion of nesting and brood-rearing habitats, and increased susceptibility of nests and young to predation. The number, location, and success of goose nests were determined through pair surveys and nest searches. Our 1985 pair count data indicated that 95 to 143 nests may have been present. Hatching success for 1985 nests (55%) was low compared to long-term averages for the region. Predation was the predominant cause of ground nest failure (25 nests); we documented 2 nest failures due to flooding. The maximum gosling count in the study area for 1985 was 197. Six key brood-rearing areas were identified. Most (80%) sites were located in the herbaceous or pasture cover type and the riparian bench landform. Analysis of aerial photographs taken prior to construction of Kerr Dam documented the loss of 1859 acres of habitat along the north shore of Flathead Lake. Losses were attributed to inundation and to continuing erosion due to operation of Kerr Dam. Lake and river water level regimes were compared with the chronology of important periods in the nesting cycle. Low lake levels in May and early June coincide with the breed-rearing period. Mudflats are heavily used by broods, but their effect on survival must still be documented. Preliminary recommendations to protect and enhance Canada goose habitat and production are being developed.

  18. BETCO: A Computer Program for the Removal of Barometric and Earth Tide Effects From Water Levels

    Science.gov (United States)

    Toll, N.; Rasmussen, T. C.

    2005-12-01

    Barometric pressure effects in long-term water level measurements can mask drawdown responses to well tests and natural stimuli. Noise caused by barometric pressure and earth tide effects complicates analysis of pressure response data using diagnostic pressure derivative plots. A computer program has been developed to remove fluctuations in groundwater levels induced by changes in barometric pressure and earth tides. The program implements a regression deconvolution method to obtain a barometric response function and remove the barometric pressure and earth tide effects from the groundwater level data. Using the barometric response function yields a better residual or corrected head than using a constant barometric efficiency. The graphical response function can be used to diagnose aquifer type and well skin effects. A modification of the regression deconvolution has been implemented to simultaneously remove earth tide effects as well as barometric effects on water levels. The removal of the earth tide effects is provided as a beta feature. The software has been applied to 13 water level data sets at the Waste Isolation Pilot Plant in Carlsbad, NM. The results are compared to a constant barometric efficiency correction method. The freeware software is available as an install wizard for Windows XP and 2000. As of submission, all results output from BETCO are considered preliminary, please do not cite. The code is under continued development and will be qualified per the Sandia National Laboratories WIPP Software QA Plan requirements. This research is funded by WIPP programs administered by the Office of Environmental Management (EM) of the U.S. Department of Energy. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  19. A high resolution water level forecast for the German Bight

    Science.gov (United States)

    Niehüser, Sebastian; Dangendorf, Sönke; Arns, Arne; Jensen, Jürgen

    2016-04-01

    Many coastal regions worldwide are potentially endangered by storm surges which can cause disastrous damages and loss of life. Due to climate change induced sea level rise, an accumulation of such events is expected by the end of the 21th century. Therefore, advanced storm surge warnings are needed to be prepared when another storm surge hits the coast. In the shallow southeastern North Sea these storm surge warnings are nowadays routinely provided for selected tide gauge locations along a coastline through state-of-the-art forecast systems, which are based on a coupled system of empirical tidal predictions and numerical storm surge forecasts. Along the German North Sea coastline, the Federal Maritime and Hydrographic Agency in cooperation with the German Weather Service is responsible for the storm surge warnings. They provide accurate, high frequency and real-time water level forecasts for up to six days ahead at selected tide gauge sites via internet, telephone and broadcast. Since water levels along the German North Sea coastline are dominated by shallow water effects and a very complex bathymetric structure of the seabed, the pointwise forecast is not necessarily transferable to un-gauged areas between the tide gauges. Here we aim to close this existing gap and develop water level forecasts with a high spatial (continuously with a resolution of at least 1 kilometer) as well as a high temporal (at least 15-minute values) resolution along the entire German North Sea coastline. We introduce a new methodology for water level forecasts which combines empirical or statistical and numerical models. While the tidal forecast is performed by non-parametric interpolation techniques between un-gauged and gauged sites, storm surges are estimated on the basis of statistical/empirical storm surge formulas taken from a numerical model hindcast. The procedure will be implemented in the operational mode forced with numerical weather forecasts.

  20. Mountain Pine Beetle Impact on Stand-level Water Balance

    Science.gov (United States)

    Reilly, J. A.; Woods, S.

    2012-12-01

    The recent mountain pine beetle (MPB) epidemic has disturbed millions of hectares throughout the Rocky Mountain West. The most persistent effects of MPB infestation on the stand-level water balance are likely concomitant with the grey stage of the disturbance cycle. The grey stage occurs within 3 to 5 years of the initial infestation after the needles of an infected tree have turned red and fallen off due to tree death. Large numbers of grey-stage trees in a stand may remain on the landscape for up to 20 years, until windthrow or another disturbance sends them to the forest floor. The greater temporal persistence of the grey stage over antecedent stages suggested that an examination of the grey stage would best capture long-term effects of MPB disturbance on the forest water balance. In this study we hypothesized that changes to the forest canopy associated with MPB disturbance may affect the stand-level water balance. The needle loss and windthrow that follows MPB disturbance is expected to increase the amount of precipitation reaching the forest floor. Additionally, overstory evapotranspiration (ET) demand is expected to decrease as MPB-induced tree mortality increases within disturbed stands. The expected cumulative effect of MPB disturbance on the stand-level water balance is an increase in soil moisture due to increased precipitation inputs and reduced overstory ET. This study was conducted in Lubrecht Experimental Forest and adjacent Bureau of Land Management areas near Missoula, Montana. Sub-canopy measurements of soil moisture, precipitation (rain and snow water equivalent), overstory transpiration and micro-meteorological data (net radiation, temperature, wind speed, etc.) were collected in three 50 x 50 meter plots. The plots consisted of a uniform stand of grey-stage lodgepole pine, a uniform stand of non-infested lodgepole pine, and a recent clear-cut stand, which served as a control unit. Water balances for each stand were constructed using a mass

  1. Quantifying Water Level Change Through Time in the North American Great Lakes

    Science.gov (United States)

    Tebbens, S. F.; Smigelski, J. R.; Barton, C. C.

    2011-12-01

    Anthropogenic and natural fluctuations including precipitation, runoff, snowmelt, water retention time, evaporation, and outflow all contribute to changes in water levels recorded in the North American Great Lakes. Changes in water levels and tides have been used as an index for physical parameters such as temperature, density, and circulation (Keeling and Whorf, 1997; Denny and Paine, 1998). In this study, NOAA verified hourly water level data ranging from 20 to 30 years in duration for five stations in Lake Michigan and four stations in Lake Superior were analyzed. Power Spectral Density calculated from a Fourier transform of the time series were found to exhibit power law scaling. The power-scaling exponent (β) was determined by fitting a power function to a log-log plot of frequency (f) or period (1/f) versus power in the frequency domain. Four distinct regions of scaling are observed with inflection points at approximately 1 day, 5 days, and 30 - 60 days. For time scales of less than one day, the power-scaling exponent (β) ranges from 0.1 to 0.5, indicating a white noise. From 1 day to 5 - 7 days, β ranges from 1.5 to 2.6, indicating moderate to strong persistence which we propose is due to frontal movements of weather systems. On timescales between 5 days and 30 - 60 days, β ranges from 0.1 to 0.4, again indicating a white noise which we propose is due to monthly and seasonal weather variations within the Great Lakes System. Beyond 30 - 60 days, all stations exhibit persistence, with β-values between 1.6 and 2.7.

  2. Quadratic controller syntheses for the steam generator water level

    Energy Technology Data Exchange (ETDEWEB)

    Arzelier, D.; Daafouz, J.; Bernussou, J.; Garcia, G

    1998-06-01

    The steam generator water level, (SGWL), control problem in the pressurized water reactor of a nuclear power plant is considered from robust control techniques point of view. The plant is a time-varying system with a non minimum phase behavior and an unstable open-loop response. The time-varying nature of the plant due to change in operating power is taken into account by including slowly time-varying uncertainty in the model. A linear Time-Invariant, (LTI) guaranteed cost quadratic stabilizing controller is designed in order to address some of the particular issues arising for such a control problem. (author) 17 refs.

  3. Plio-Pleistocene sea level and temperature fluctuations in the northwestern Pacific promoted speciation in the globally-distributed flathead mullet Mugil cephalus

    Directory of Open Access Journals (Sweden)

    Durand Jean-Dominique

    2011-03-01

    Full Text Available Abstract Background The study of speciation in the marine realm is challenging because of the apparent absence of physical barriers to dispersal, which are one of the main drivers of genetic diversity. Although phylogeographic studies using mitochondrial DNA (mtDNA information often reveal significant genetic heterogeneity within marine species, the evolutionary significance of such diversity is difficult to interpret with these markers. In the northwestern (NW Pacific, several studies have emphasised the potential importance of sea-level regression during the most recent glaciations as a driver of genetic diversity in marine species. These studies have failed, however, to determine whether the period of isolation was long enough for divergence to attain speciation. Among these marine species, the cosmopolitan estuarine-dependent fish Mugil cephalus represents an interesting case study. Several divergent allopatric mtDNA lineages have been described in this species worldwide, and three occur in sympatry in the NW Pacific. Results Ten nuclear microsatellites were surveyed to estimate the level of genetic isolation of these lineages and determine the role of sea-level fluctuation in the evolution of NW Pacific M. cephalus. Three cryptic species of M. cephalus were identified within this region (NWP1, 2 and 3 using an assignment test on the microsatellite data. Each species corresponds with one of the three mtDNA lineages in the COI phylogenetic tree. NWP3 is the most divergent species, with a distribution range that suggests tropical affinities, while NWP1, with a northward distribution from Taiwan to Russia, is a temperate species. NWP2 is distributed along the warm Kuroshio Current. The divergence of NWP1 from NWP2 dates back to the Pleistocene epoch and probably corresponds to the separation of the Japan and China Seas when sea levels dropped. Despite their subsequent range expansion since this period of glaciation, no gene flow was observed

  4. The effects of using ground water to maintain water levels of Cedar Lake, Wisconsin

    Science.gov (United States)

    McLeod, R.S.

    1980-01-01

    Cedar Lake, a kettle lake with no surface inlet or outlet, was studied to evaluate the feasibility of maintaining water levels of lakes in the glaciated kettle moraine area of eastern Wisconsin by pumping ground water into them. The general hydrogeology of the area around the lake was defined and the hydrology of the lake was studied in detail.

  5. Comparison of nitrate levels in raw water and finished water from historical monitoring data on Iowa municipal drinking water supplies.

    Science.gov (United States)

    Weyer, Peter J; Smith, Brian J; Feng, Zhen-Fang; Kantamneni, Jiji R; Riley, David G

    2006-05-01

    Nitrate contamination of water sources is a concern where large amounts of nitrogen fertilizers are regularly applied to soils. Ingested nitrate from dietary sources and drinking water can be converted to nitrite and ultimately to N-nitroso compounds, many of which are known carcinogens. Epidemiologic studies of drinking water nitrate and cancer report mixed findings; a criticism is the use of nitrate concentrations from retrospective drinking water data to assign exposure levels. Residential point-of-use nitrate data are scarce; gaps in historical data for municipal supply finished water hamper exposure classification efforts. We used generalized linear regression models to estimate and compare historical raw water and finished water nitrate levels (1960s-1990s) in single source Iowa municipal supplies to determine whether raw water monitoring data could supplement finished water data to improve exposure assessment. Comparison of raw water and finished water samples (same sampling date) showed a significant difference in nitrate levels in municipalities using rivers; municipalities using other surface water or alluvial groundwater had no difference in nitrate levels. A regional aggregation of alluvial groundwater municipalities was constructed based on results from a previous study showing regional differences in nitrate contamination of private wells; results from this analysis were mixed, dependent upon region and decade. These analyses demonstrate using historical raw water nitrate monitoring data to supplement finished water data for exposure assessment is appropriate for individual Iowa municipal supplies using alluvial groundwater, lakes or reservoirs. Using alluvial raw water data on a regional basis is dependent on region and decade.

  6. Sedimentary archaeal amoA gene abundance reflects historic nutrient level and salinity fluctuations in Qinghai Lake, Tibetan Plateau

    Science.gov (United States)

    Yang, Jian; Jiang, Hongchen; Dong, Hailiang; Hou, Weiguo; Li, Gaoyuan; Wu, Geng

    2015-12-01

    Integration of DNA derived from ancient phototrophs with their characteristic lipid biomarkers has been successfully employed to reconstruct paleoenvironmental conditions. However, it is poorly known that whether the DNA and lipids of microbial functional aerobes (such as ammonia-oxidizing archaea: AOA) can be used for reconstructing past environmental conditions. Here we identify and quantify the AOA amoA genes (encoding the alpha subunit of ammonia monooxygenases) preserved in a 5.8-m sediment core (spanning the last 18,500 years) from Qinghai Lake. Parallel analyses revealed that low amoA gene abundance corresponded to high total organic carbon (TOC) and salinity, while high amoA gene abundance corresponded to low TOC and salinity. In the Qinghai Lake region, TOC can serve as an indicator of paleo-productivity and paleo-precipitation, which is related to historic nutrient input and salinity. So our data suggest that temporal variation of AOA amoA gene abundance preserved in Qinghai Lake sediment may reflect the variations of nutrient level and salinity throughout the late Pleistocene and Holocene in the Qinghai Lake region.

  7. Predicting the residual aluminum level in water treatment process

    Directory of Open Access Journals (Sweden)

    J. Tomperi

    2012-06-01

    Full Text Available In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP was analyzed and the residual aluminum in drinking water was predicted using Multiple Linear Regression (MLR and Artificial Neural Network (ANN models. The purpose was to find out which variables affect the amount of residual aluminum and create simple and reliable prediction models which can be used in an early warning system (EWS. Accuracy of ANN and MLR models were compared. The new nonlinear scaling method based on generalized norms and skewness was used to scale all measurement variables to range [−2...+2] before data-analysis and modeling. The effect of data pre-processing was studied by comparing prediction results to ones achieved in an earlier study. Results showed that it is possible to predict the baseline level of residual aluminum in drinking water with a simple model. Variables that affected the most the amount of residual aluminum were among others: raw water temperature, raw water KMnO4 and PAC / KMnO4-ratio. The accuracies of MLR and ANN models were found to be almost equal. Study also showed that data pre-processing affects to the final prediction result.

  8. Predicting the residual aluminum level in water treatment process

    Directory of Open Access Journals (Sweden)

    J. Tomperi

    2013-06-01

    Full Text Available In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease. Thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP was analyzed and the residual aluminum in drinking water was predicted using Multiple Linear Regression (MLR and Artificial Neural Network (ANN models. The purpose was to find out which variables affect the amount of residual aluminum and create simple and reliable prediction models which can be used in an early warning system (EWS. Accuracy of ANN and MLR models were compared. The new nonlinear scaling method based on generalized norms and skewness was used to scale all measurement variables to range [−2...+2] before data-analysis and modeling. The effect of data pre-processing was studied by comparing prediction results to ones achieved in an earlier study. Results showed that it is possible to predict the baseline level of residual aluminum in drinking water with a simple model. Variables that affected the most the amount of residual aluminum were among others: raw water temperature, raw water KMnO4 and PAC/KMnO4 (Poly-Aluminum Chloride/Potassium permanganate-ratio. The accuracies of MLR and ANN models were found to be almost the same. Study also showed that data pre-processing affects to the final prediction result.

  9. Effect of water level lfuctuations on temporal-spatial patterns of foraging activities by the wintering Hooded Crane (Grus monacha)

    Institute of Scientific and Technical Information of China (English)

    Dongmei Zhang; Lizhi Zhou; Yunwei Song

    2015-01-01

    Background: The Yangtze River lfoodplain provides important wintering habitats for Hooded Cranes (Grus monacha) in China. Fluctuations in the water level change foraging habitat and food availability, affecting their temporal-spatial patterns of foraging activities. It is of considerable importance to investigate the effect of these lfuctuations on food availability for wintering Hooded Cranes and their foraging response to these changes. Understanding their behavior patterns is beneifcial in protecting the wintering crane population and restoring their wintering habitats. Methods: A ifeld survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014. Habitat variables, as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during ifve stages of water level lfuctuation were collected. Based on this data we analyzed the relation-ship of foraging behavior relative to water level lfuctuations and habitat types. Results: The foraging habitats used by Hooded Cranes varied at the different water level stages. As the water level decreased, the use of meadows and mudlfats increased. When the water dropped to its lowest level, the use by the Hooded Crane in the mudlfats reached a peak. There were statistically signiifcant differences in time budget in the three types of habitats over the ifve stages of the water level. In the mudlfats, the foraging behavior and maintenance behavior varied signiifcantly with the water level, while the alert behavior showed little variation. Analysis of a general-ized linear model showed that the ifve water level stages and three habitat types had a signiifcant effect on forag- ing behavior, while the combined effect of these two variables was signiifcant on the foraging time budget and the length of foraging activity of the Hooded Crane. Conclusions: With the decrease in the water level, the use of mudlfats by Hooded Cranes increased

  10. Investigation of natural radioactivity levels in water around Kadugli, Sudan

    International Nuclear Information System (INIS)

    Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for 238U, 226Ra, 222Rn, and 232Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: -1 for 238U, 226Ra, 222Rn, and 232Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, -1) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr-1 except in one groundwater sample with an associated dose of 0.7 mSv yr-1

  11. The Water Level Fall of Lake Megali Prespa (N Greece): an Indicator of Regional Water Stress Driven by Climate Change and Amplified by Water Extraction?

    Science.gov (United States)

    van der Schriek, Tim; Giannakopoulos, Christos

    2014-05-01

    The Mediterranean stands out globally due to its sensitivity to (future) climate change, with future projections predicting an increase in excessive drought events and declining rainfall. Regional freshwater ecosystems are particularly threatened: precipitation decreases, while extreme droughts increase and human impacts intensify (e.g. water extraction, drainage, pollution and dam-building). Many Mediterranean lake-wetland systems have shrunk or disappeared over the past two decades. Protecting the remaining systems is extremely important for supporting global biodiversity and for ensuring sustainable water availability. This protection should be based on a clear understanding of lake-wetland hydrological responses to natural and human-induced changes, which is currently lacking in many parts of the Mediterranean. The interconnected Prespa-Ohrid Lake system is a global hotspot of biodiversity and endemism. The unprecedented fall in water level (~8m) of Lake Megali Prespa threatens this system, but causes remain debated. Modelling suggests that the S Balkan will experience rainfall and runoff decreases of ~30% by 2050. However, projections revealing the potential impact of these changes on future lake level are unavailable as lake regime is not understood. A further drop in lake level may have serious consequences. The Prespa Lakes contribute ~25% of the total inflow into Lake Ohrid through underground karst channels; falling lake levels decrease this discharge. Lake Ohrid, in turn, feeds the Drim River. This entire catchment may therefore be affected by falling lake levels; its water resources are of great importance for Greece, Albania, FYROM and Montenegro (e.g. tourism, agriculture, hydro-energy, urban & industrial use). This new work proves that annual water level fluctuations of Lake Megali Prespa are predominantly related to precipitation during the first 7 months (Oct-Apr) of the hydrological year (Oct-Sep). Lake level is very sensitive to regional and

  12. Hydrology and water quality of Shell Lake, Washburn County, Wisconsin, with special emphasis on the effects of diversion and changes in water level on the water quality of a shallow terminal lake

    Science.gov (United States)

    Juckem, Paul F.; Robertson, Dale M.

    2013-01-01

    Shell Lake is a relatively shallow terminal lake (tributaries but no outlets) in northwestern Wisconsin that has experienced approximately 10 feet (ft) of water-level fluctuation over more than 70 years of record and extensive flooding of nearshore areas starting in the early 2000s. The City of Shell Lake (City) received a permit from the Wisconsin Department of Natural Resources in 2002 to divert water from the lake to a nearby river in order to lower water levels and reduce flooding. Previous studies suggested that water-level fluctuations were driven by long-term cycles in precipitation, evaporation, and runoff, although questions about the lake’s connection with the groundwater system remained. The permit required that the City evaluate assumptions about lake/groundwater interactions made in previous studies and evaluate the effects of the water diversion on water levels in Shell Lake and other nearby lakes. Therefore, a cooperative study between the City and U.S. Geological Survey (USGS) was initiated to improve the understanding of the hydrogeology of the area and evaluate potential effects of the diversion on water levels in Shell Lake, the surrounding groundwater system, and nearby lakes. Concerns over deteriorating water quality in the lake, possibly associated with changes in water level, prompted an additional cooperative project between the City and the USGS to evaluate efeffects of changes in nutrient loading associated with changes in water levels on the water quality of Shell Lake. Numerical models were used to evaluate how the hydrology and water quality responded to diversion of water from the lake and historical changes in the watershed. The groundwater-flow model MODFLOW was used to simulate groundwater movement in the area around Shell Lake, including groundwater/surface-water interactions. Simulated results from the MODFLOW model indicate that groundwater flows generally northward in the area around Shell Lake, with flow locally converging

  13. A multiresidue method to evaluate emerging micropollutants levels in waters

    OpenAIRE

    Lionard, E.; Serveto, F.; Desbiolles, F.; Daval, A.; Coquery, M.; Miège, C.

    2015-01-01

    During the last decade, the interest on the fate of emerging organic micropollutants, including pharmaceuticals and pesticides, in rivers and waste waters has constantly grown. Analysis of these pollutants at trace level in complex matrices is an analytical challenge that requires the development of reliable analytical methods. Based on the conclusions of national research programs on wastewater and sludge treatments and on expert opinions, indicative compounds typical of urban domestic pollu...

  14. Analytical approach for predicting fresh water discharge in an estuary based on tidal water level observations

    Directory of Open Access Journals (Sweden)

    H. Cai

    2014-06-01

    Full Text Available As the tidal wave propagates into an estuary, the tidally averaged water level tends to rise in landward direction due to the density difference between saline and fresh water and the asymmetry of the friction. The effect of friction on the residual slope is even more remarkable when accounting for fresh water discharge. In this study, we investigate the influence of river discharge on tidal wave propagation in the Yangtze estuary with specific attention to residual water level slope. This is done by using a one-dimensional analytical model for tidal hydrodynamics accounting for the residual water level. We demonstrate the importance of the residual slope on tidal dynamics and use it to improve the prediction of the tidal propagation in estuaries (i.e., tidal damping, velocity amplitude, wave celerity and phase lag, especially when the influence of river discharge is significant. Finally, we develop a new inverse analytical approach for estimating fresh water discharge on the basis of tidal water level observations along the estuary, which can be used as a tool to obtain information on the river discharge that is otherwise difficult to measure in the tidal region.

  15. Long term fluctuations of groundwater mine pollution in a sulfide mining district with dry Mediterranean climate: Implications for water resources management and remediation.

    Science.gov (United States)

    Caraballo, Manuel A; Macías, Francisco; Nieto, José Miguel; Ayora, Carlos

    2016-01-01

    Water resources management and restoration strategies, and subsequently ecological and human life quality, are highly influenced by the presence of short and long term cycles affecting the intensity of a targeted pollution. On this respect, a typical acid mine drainage (AMD) groundwater from a sulfide mining district with dry Mediterranean climate (Iberian Pyrite Belt, SW Spain) was studied to unravel the effect of long term weather changes in water flow rate and metal pollutants concentration. Three well differentiated polluting stages were observed and the specific geochemical, mineralogical and hydrological processes involved (pyrite and enclosing rocks dissolution, evaporitic salts precipitation-redisolution and pluviometric long term fluctuations) were discussed. Evidencing the importance of including longer background monitoring stage in AMD management and restoration strategies, the present study strongly advise a minimum 5-years period of AMD continuous monitoring previous to the design of any AMD remediation system in regions with dry Mediterranean climate.

  16. The Application of a Grey Markov Model to Forecasting Annual Maximum Water Levels at Hydrological Stations

    Institute of Scientific and Technical Information of China (English)

    DONG Sheng; CHI Kun; ZHANG Qiyi; ZHANG Xiangdong

    2012-01-01

    Compared with traditional real-time forecasting,this paper proposes a Grey Markov Model (GMM) to forecast the maximum water levels at hydrological stations in the estuary area.The GMM combines the Grey System and Markov theory into a higher precision model.The GMM takes advantage of the Grey System to predict the trend values and uses the Markov theory to forecast fluctuation values,and thus gives forecast results involving two aspects of information.The procedure for forecasting annul maximum water levels with the GMM contains five main steps:1) establish the GM (1,1) model based on the data series; 2) estimate the trend values; 3) establish a Markov Model based on relative error series; 4) modify the relative errors caused in step 2,and then obtain the relative errors of the second order estimation; 5) compare the results with measured data and estimate the accuracy.The historical water level records (from 1960 to 1992) at Yuqiao Hydrological Station in the estuary area of the Haihe River near Tianjin,China are utilized to calibrate and verify the proposed model according to the above steps.Every 25 years' data are regarded as a hydro-sequence.Eight groups of simulated results show reasonable agreement between the predicted values and the measured data.The GMM is also applied to the 10 other hydrological stations in the same estuary.The forecast results for all of the hydrological stations are good or acceptable.The feasibility and effectiveness of this new forecasting model have been proved in this paper.

  17. Reservoir Computing approach to Great Lakes water level forecasting

    Science.gov (United States)

    Coulibaly, Paulin

    2010-02-01

    SummaryThe use of echo state network (ESN) for dynamical system modeling is known as Reservoir Computing and has been shown to be effective for a number of applications, including signal processing, learning grammatical structure, time series prediction and motor/system control. However, the performance of Reservoir Computing approach on hydrological time series remains largely unexplored. This study investigates the potential of ESN or Reservoir Computing for long-term prediction of lake water levels. Great Lakes water levels from 1918 to 2005 are used to develop and evaluate the ESN models. The forecast performance of the ESN-based models is compared with the results obtained from two benchmark models, the conventional recurrent neural network (RNN) and the Bayesian neural network (BNN). The test results indicate a strong ability of ESN models to provide improved lake level forecasts up to 10-month ahead - suggesting that the inherent structure and innovative learning approach of the ESN is suitable for hydrological time series modeling. Another particular advantage of ESN learning approach is that it simplifies the network training complexity and avoids the limitations inherent to the gradient descent optimization method. Overall, it is shown that the ESN can be a good alternative method for improved lake level forecasting, performing better than both the RNN and the BNN on the four selected Great Lakes time series, namely, the Lakes Erie, Huron-Michigan, Ontario, and Superior.

  18. Seasonal Fluctuations In Co, Ni, Cu, Zn, Cd, Pb Concentrations In Surface Microlayers And Subsurface Water Of Two City Ponds

    Directory of Open Access Journals (Sweden)

    Antonowicz J. P.

    2013-04-01

    Full Text Available We owe the knowledge concerning the surface water microlayer to the wide research into marine environment and relatively scarce research done into inland city ponds ecosystems. The surface microlayer is a very thin, several hundred micrometers thick layer at the contact of water and atmosphere. This important form of air-water exchange ecotone, which constitutes the surface microlayer of water, is a specific environment as to its chemical and physical characteristics and is different from subsurface waters. It can absorb chemical substances like heavy metals, phytoneuston and bacteria in larger quantities in comparison to lower parts of the water. This characteristic feature results, among others, from the processes of transport at the contact of hydrosphere-atmosphere and also transport within the very area of surface water microlayer. The paper describes transport processes of six heavy metals: Co, Ni, Cu, Zn, Cd, Pb from subsurface water to surface water microlayer and vice versa, analyzed in a one year cycle. The transport of chemical substances under consideration was described on a basis of experiments made during the period of one year at five city pounds in Słupsk (Polish Pomerania. During the research, samples of the surface water microlayer were collected by means of application of the Garrett mesh technique. At the same time, samples of subsurface water were collected and tested as to the content of the same parameters as the surface microlayer. Samples were sampled in month intervals. The concentration of aforementioned heavy metals was measured by mass spectrometry method and used Perkin Elmer Elan DRC aparature.

  19. FLUCTUATION CHARACTERISTICS OF HOLOCENE SEA-LEVEL CHANGE AND ITS ENVIRONMENTAL IMPLICATIONS%略论全新世海面变化的波动性及其环境意义

    Institute of Scientific and Technical Information of China (English)

    谢志仁; 袁林旺

    2012-01-01

    Sea-level change and climate change are interrelated multiscale natural processes with profound spatial and temporal span connotation. Historical fact and event recognition of millennium to centennial scale sea level fluctuations and their relation to climate fluctuations are not only the foundation and theoretical issues of sea level change studies, but also very important for in-depth understanding of historical and future trends of coastal environment in both reality and conceptual issues. Based on land-sea level system,this paper integrates statistical analysis, simulation based on models and virtual environment test, and research on a variety of sea level change proxy data. The eastern China and global mean sea level series during the last 20ka are reconstructed based on 67 series selected from 130 global studies on regional sea level series and 12 Holocene series of China coast as well as 667 proxy data of historical sea level with different space-time scales. The fluctuations of different temporal scales are analyzed in details. The division of the millennial fluctuations in Holocene of eastern China and global average sea level is proposed as well as the division of centennial sea level fluctuations over the past 2ka. Then the correspondence between sea-level fluctuations and the global and China temperature fluctuations of the corresponding period are discussed. Based on the land-sea level system virtual simulation and experimental platform,the evolution of the sea-land relationship in the Yangtze River Delta is simulated, which suggests that the land-sea system evolution in Yangtze River Delta can be divided into early,middle and late stages. The early stage, spanning 10.0 ~ 7.0ka, is a period when sea level raised very quickly and the sea area expanded rapidly. In the middle stages, spanning 7. 0 ~ 2. 5 ka, the sea level raised a little and sea area oscillated a.t a high level; In the late stage,spanning 2. 5 ~0ka,the sea level decrease slightly and the

  20. Concentrating Low-Level Tritiated Water Through Isotope Exchange

    International Nuclear Information System (INIS)

    Trapping of tritium on polymers with specific functional groups was investigated as a means of treating waste streams containing low levels of tritium. Chemical exchange of tritium with hydrogen on the functional group was used as the mechanism for trapping. The polymers tested include Aurorez polybenzimidazole resin beads, Chelex 100 resin beads, Duolite GT-73, microcrystalline cellulose, and polyethylenimine. The tests were performed under simulated operating conditions on water obtained from the Radioactive Liquid Waste Treatment Facility at Los Alamos National Laboratory. Tritiated water from the Tritium Systems Test Assembly is discharged to this plant. Polyethylenimine is a water-soluble polymer that was tested using a stirred membrane cell with an ultrafiltration membrane. All of the polymers except polyethylenimine took up tritium from the water. Polybenzimidazole demonstrated the highest tritium uptake. The results are explained on the basis of the type of functional group, hydrogen bonding, and rigidity of the molecular structure of the polymer. The theoretical calculations indicate that significant isotope discrimination requires high-frequency modes with hydrogen bonding contribution and support the experimental findings. Modeling suggested trends that may lead to structures that are more efficient in trapping tritium

  1. Concentrating low-level tritiated water through isotope exchange

    International Nuclear Information System (INIS)

    Trapping of tritium on polymers with specific functional groups was investigated as a means of treating waste streams containing low levels of tritium. Chemical exchange of tritium with hydrogen on the functional group was used as the mechanism for trapping. The polymers tested include Aurorez polybenzimidazole resin beads, Chelex 100 resin beads, Duolite GT-73, microcrystalline cellulose, and polyethylenimine. The tests were performed under simulated operating conditions on water obtained from the Radioactive Liquid Waste Treatment Facility at Los Alamos National Laboratory, Tritiated water from the Tritium Systems Test Assembly is discharged to this plant. Polyethylenimine is a water-soluble polymer that was tested using a stirred membrane cell with an ultrafiltration membrane. All of the polymers except polyethylenimine took up tritium from the water. Polybenzimidazole demonstrated the highest tritium uptake. The results are explained on the basis of the type of functional group, hydrogen bonding, and rigidity of the molecular structure of the polymer. The theoretical calculations indicate that significant isotope discrimination requires high-frequency modes with hydrogen bonding contribution and support the experimental findings. Modeling suggested trends that may lead to structures that are more efficient in trapping tritium

  2. Considering rating curve uncertainty in water level predictions

    Science.gov (United States)

    Sikorska, A. E.; Scheidegger, A.; Banasik, K.; Rieckermann, J.

    2013-11-01

    Streamflow cannot be measured directly and is typically derived with a rating curve model. Unfortunately, this causes uncertainties in the streamflow data and also influences the calibration of rainfall-runoff models if they are conditioned on such data. However, it is currently unknown to what extent these uncertainties propagate to rainfall-runoff predictions. This study therefore presents a quantitative approach to rigorously consider the impact of the rating curve on the prediction uncertainty of water levels. The uncertainty analysis is performed within a formal Bayesian framework and the contributions of rating curve versus rainfall-runoff model parameters to the total predictive uncertainty are addressed. A major benefit of the approach is its independence from the applied rainfall-runoff model and rating curve. In addition, it only requires already existing hydrometric data. The approach was successfully demonstrated on a small catchment in Poland, where a dedicated monitoring campaign was performed in 2011. The results of our case study indicate that the uncertainty in calibration data derived by the rating curve method may be of the same relevance as rainfall-runoff model parameters themselves. A conceptual limitation of the approach presented is that it is limited to water level predictions. Nevertheless, regarding flood level predictions, the Bayesian framework seems very promising because it (i) enables the modeler to incorporate informal knowledge from easily accessible information and (ii) better assesses the individual error contributions. Especially the latter is important to improve the predictive capability of hydrological models.

  3. Considering rating curve uncertainty in water level predictions

    Directory of Open Access Journals (Sweden)

    A. E. Sikorska

    2013-03-01

    Full Text Available Streamflow cannot be measured directly and is typically derived with a rating curve model. Unfortunately, this causes uncertainties in the streamflow data and also influences the calibration of rainfall-runoff models if they are conditioned on such data. However, it is currently unknown to what extent these uncertainties propagate to rainfall-runoff predictions. This study therefore presents a quantitative approach to rigorously consider the impact of the rating curve on the prediction uncertainty of water levels. The uncertainty analysis is performed within a formal Bayesian framework and the contributions of rating curve versus rainfall-runoff model parameters to the total predictive uncertainty are addressed. A major benefit of the approach is its independence from the applied rainfall-runoff model and rating curve. In addition, it only requires already existing hydrometric data. The approach was successfully tested on a small urbanized basin in Poland, where a dedicated monitoring campaign was performed in 2011. The results of our case study indicate that the uncertainty in calibration data derived by the rating curve method may be of the same relevance as rainfall-runoff model parameters themselves. A conceptual limitation of the approach presented is that it is limited to water level predictions. Nevertheless, regarding flood level predictions, the Bayesian framework seems very promising because it (i enables the modeler to incorporate informal knowledge from easily accessible information and (ii better assesses the individual error contributions. Especially the latter is important to improve the predictive capability of hydrological models.

  4. Influence of Closing Storm Surge Barrier on Extreme Water Levels and Water Exchange; The Limfjord, Denmark

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen Quvang Harck; Bentzen, Thomas Ruby; Larsen, Torben;

    2014-01-01

    the increased risk of flooding in the estuary has revitalized the discussion whether this connection should be closed. In this paper, it is shown by numerical simulation that the establishment of a storm surge barrier across Thyborøn Channel can significantly reduce the peak water levels in the central...... of the fjord. The reduction is obtained by blocking the ingoing flow with a sluice in due time before the storm surge peaks in the North Sea. In order to avoid problems with reduced water quality and salinity, the water exchange should be controlled by only keeping the sluice open for ingoing currents...

  5. Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress coupling analysis

    Institute of Scientific and Technical Information of China (English)

    DONG Qing-hong; SUI Wang-hua; ZHANG Xiao-cui; MAO Zeng-min

    2009-01-01

    Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face.

  6. Projected climate change effects on water level of an oxbow

    Science.gov (United States)

    Hunyady, Adrienn

    One of the most vulnerable regions in the Carpathian Basin is the Great Hungarian Plain, where small and shallow oxbows are endangered along river Tisza. The purpose of this paper is to determine how the global warming affects a typical oxbow, located on the floodplain of river Tisza, in Hungary. A coupled meteorological-hydraulic model is developed and applied for this oxbow. Results suggest that the monthly minimum water levels are expected to decrease, moreover, extreme drought events sometimes result temporary drying-up of the oxbow.

  7. How geomorphology and groundwater level affect the spatio-temporal variability of riverine cold water patches?

    Science.gov (United States)

    Wawrzyniak, Vincent; Piégay, Hervé; Allemand, Pascal; Vaudor, Lise; Goma, Régis; Grandjean, Philippe

    2016-04-01

    Temperature is a key factor for river ecosystems. In summer, patches of cold water are formed in the river by groundwater seepage. These patches have strong ecological significance and extend to the surface water in a well-mixed riverine system. These patches can serve as thermal refuges for some fish species during summer. In this study, the temporal variability and spatial distribution of cold water patches were explored along a 50 km river reach (the lower Ain River, France) using thermal infrared airborne remote sensing. This study examines a new range of processes acting on cold water patches at different scales that have not previously been touched upon in the literature. Three airborne campaigns were conducted during the summers of 2010, 2011 and 2014. Based on these images, a large number of cold water patches were identified using an automated method. Four types of patches were observed: tributary plumes, cold side channels (former channels or point-bar backwater channels), side seeps (located directly in the river channel) and gravel bar seeps (occurring at the downstream end of gravel bars). Logistic regression was used to analyse the longitudinal distribution of cold water patches according to geomorphologic indicators reflecting current or past fluvial process. Side seeps were found to be related to the local geology. Cold side channels were correlated to contemporary and past lateral river mobility. Gravel bar seeps were related to the current development of bars and are more prevalent in wandering reaches than in single-bed incised and paved reaches. The logistic model was subsequently used to evaluate gravel bar seep variability in the past. The model suggests larger numbers of seeps in the mid-20th century when bar surface area was higher. Interannual variability in the occurrence and spatial extent of side seeps and gravel bar seeps appear to be related to groundwater level fluctuations. Cold side channels exhibited greater interannual stability

  8. Bode Analysis and Modeling of Water Level Change in the Great Lakes

    Science.gov (United States)

    Tebbens, S. F.; Smigelski, J. R.; Barton, C. C.

    2009-12-01

    Power Spectral Density calculated from a fast Fourier transform expresses a time series in terms of power in the corresponding frequency domain. The power-scaling exponent ( β ) is determined by fitting a power function to a log-log plot of frequency ( f ) or period ( 1/f ) versus power in the frequency domain. Anthropogenic and natural fluctuations including precipitation, runoff, snowmelt, water retention time, evaporation, and outflow all contribute to changes in water levels recorded in the Great Lakes. In this study, NOAA verified hourly water level data ranging from 20 to 30 years in duration for five stations in Lake Michigan and four stations in Lake Superior were analyzed. Water level time series in the Great Lakes are found to exhibit power law scaling and are thus self-affine over four distinct period ranges, each with a different beta value. With this information, a model of the original time series may be generated using an approach which draws from concepts in control theory and feedback systems. Bode Analysis can be applied in the frequency domain to explain variations in the scaling behavior ( β ) of water level data by examining the patterns of change in amplitude and phase across frequencies. A Bode magnitude plot of the system is created from the data of power versus frequency converting the amplitude to 20log dB magnitude. A transfer function representing the output of the system divided by the input is then derived based on the data using Laplace transforms and solved for magnitude and phase. Bode analysis results in a series of two transfer function equations, one for magnitude and one for phase, for each distinct beta value over the specified period range. The type of differential equation controls the slope ( β ) while the constant (k) in the differential equation controls the position (period) of transitions in scaling behavior (i.e., corner frequencies or inflection points) and are characteristics of the system. Combining the transfer

  9. Impact assessment of climate change and human activities on annual highest water level of Taihu Lake

    Institute of Scientific and Technical Information of China (English)

    Qing-fang HU; Yin-tang WANG

    2009-01-01

    The annual highest water level of Taihu Lake (Zm) is very significant for flood management in the Taihu Basin. This paper first describes the inter-annual and intra-annual traits of Zm from 1956 to 2000. Then, using the Mann-Kenall (MK) and Spearman (SP) nonparametric tests, the long-term change trends of area precipitation and pan evaporation in the Taihu Basin are determined. Meanwhile, using the Morlet wavelet transformation, the fluctuation patterns and change points of precipitation and pan evaporation are analyzed. Also, human activities in the Taihu Basin are described, including land use change and hydraulic project construction. Finally, the relationship between Zm, the water level of Taihu Lake 30 days prior to the day of Zm (Z0), and the 30-day total precipitation and pan evaporation prior to the day of Zm (P and E0, respectively) is described based on multi-linear regression equations. The relative influence of climate change and human activities on the change of Zm is quantitatively ascertained. The results demonstrate that: (1) Zm was distinctly higher during the 1980-2000 period than during the 1956-1979 period, and the 30 days prior to the day of Zm are the key phase influencing Zm every year; (2) P increased significantly at a confidence level of 95% during the 1956-2000 period, while the reverse was true for E0; (3) The relationship between Zm, P and E0 distinctly changed after 1980; (4) Climate change and human activities together caused frequent occurrences of high Zm after 1980; (5) Climate change caused a substantially greater Zm difference between the 1956-1979 and 1980-2000 periods than human activities. Climate change, as represented by P and E0, was the dominant factor raising Zm, with a relative influence ratio of 83.6%, while human activities had a smaller influence ratio of 16.4%.

  10. Frequency fluctuations in silicon nanoresonators

    Science.gov (United States)

    Sansa, Marc; Sage, Eric; Bullard, Elizabeth C.; Gély, Marc; Alava, Thomas; Colinet, Eric; Naik, Akshay K.; Villanueva, Luis Guillermo; Duraffourg, Laurent; Roukes, Michael L.; Jourdan, Guillaume; Hentz, Sébastien

    2016-06-01

    Frequency stability is key to the performance of nanoresonators. This stability is thought to reach a limit with the resonator's ability to resolve thermally induced vibrations. Although measurements and predictions of resonator stability usually disregard fluctuations in the mechanical frequency response, these fluctuations have recently attracted considerable theoretical interest. However, their existence is very difficult to demonstrate experimentally. Here, through a literature review, we show that all studies of frequency stability report values several orders of magnitude larger than the limit imposed by thermomechanical noise. We studied a monocrystalline silicon nanoresonator at room temperature and found a similar discrepancy. We propose a new method to show that this was due to the presence of frequency fluctuations, of unexpected level. The fluctuations were not due to the instrumentation system, or to any other of the known sources investigated. These results challenge our current understanding of frequency fluctuations and call for a change in practices.

  11. Establishing solar water disinfection as a water treatment method at household level

    Directory of Open Access Journals (Sweden)

    Regula Meierhofer

    2006-12-01

    Full Text Available 1.1 billion People worldwide do not have access to safe drinking water and therefore are exposed to a high risk for diarrhoeal diseases. As a consequence, about 6,000 children die each day of dehydration due to diarrhoea. Adequate water treatment methods and safe storage of drinking water, combined with hygiene promotion, are required to prevent the population without access to safe drinking water from illness and death. Solar water disinfection (SODIS is a new water treatment to be applied at household level with a great potential to reduce diarrhoea incidence of users. The method is very simple and the only resources required for its application are transparent PET plastic bottles (or glass bottles and sufficient sunlight: microbiologically contaminated water is filled into the bottles and exposed to the full sunlight for 6 hours. During solar exposure, the diarrhoea causing pathogens are killed by the UV-A radiation of the sunlight. At present, SODIS is used by about 2 Million users in more than 20 countries of the South. Diarrhoea incidence of users significantly has been reduced by 30 to 70 %. A careful and long-term community education process that involves creating awareness on the importance of treating drinking water and initiates behaviour change is required to establish the sustainable practice of SODIS at community level. In Madagascar, more than 160 children younger than 5 years die each day from malaria, diarrhoea and acute respiratory illnesses. The application of household water treatment methods such as SODIS significantly could contribute to improve their health.

  12. Investigation of natural radioactivity levels in water around Kadugli, Sudan

    Energy Technology Data Exchange (ETDEWEB)

    Osman, Alfatih A.A. [Sudan Atomic Energy Commission, P.O. Box 3001, Khartoum (Sudan)], E-mail: alfatih_123@yahoo.com; Salih, Isam; Shaddad, Ibrahim A.; El Din, Saif; Siddeeg, M.B.; Eltayeb, Hatem; Idriss, Hajo; Hamza, Walid; Yousif, E.H. [Sudan Atomic Energy Commission, P.O. Box 3001, Khartoum (Sudan)

    2008-11-15

    Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for {sup 238}U, {sup 226}Ra, {sup 222}Rn, and {sup 232}Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: <1.0-7.5, 8.5-16.5, <1.6, and <0.1-0.39 mBq L{sup -1} for {sup 238}U, {sup 226}Ra, {sup 222}Rn, and {sup 232}Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, <0.1-39 mBq L{sup -1}) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr{sup -1} except in one groundwater sample with an associated dose of 0.7 mSv yr{sup -1}.

  13. Responses of gas-exchange rates and water relations to annual fluctuations of weather in three species of urban street trees.

    Science.gov (United States)

    Osone, Yoko; Kawarasaki, Satoko; Ishida, Atsushi; Kikuchi, Satoshi; Shimizu, Akari; Yazaki, Kenichi; Aikawa, Shin-Ichi; Yamaguchi, Masahiro; Izuta, Takeshi; Matsumoto, Genki I

    2014-10-01

    The frequency of extreme weather has been rising in recent years. A 3-year study of street trees was undertaken in Tokyo to determine whether: (i) street trees suffer from severe water stress in unusually hot summer; (ii) species respond differently to such climatic fluctuations; and (iii) street trees are also affected by nitrogen (N) deficiency, photoinhibition and aerosol pollution. During the study period (2010-12), midsummers of 2010 and 2012 were unusually hot (2.4-2.8 °C higher maximum temperature than the long-term mean) and dry (6-56% precipitation of the mean). In all species, street trees exhibited substantially decreased photosynthetic rate in the extremely hot summer in 2012 compared with the average summer in 2011. However, because of a more conservative stomatal regulation (stomatal closure at higher leaf water potential) in the hot summer, apparent symptoms of hydraulic failure were not observed in street trees even in 2012. Compared with Prunus × yedoensis and Zelkova serrata, Ginkgo biloba, a gymnosperm, was high in stomatal conductance and midday leaf water potential even under street conditions in the unusually hot summer, suggesting that the species had higher drought resistance than the other species and was less susceptible to urban street conditions. This lower susceptibility might be ascribed to the combination of higher soil-to-leaf hydraulic conductance and more conservative water use. Aside from meteorological conditions, N deficiency affected street trees significantly, whereas photoinhibition and aerosol pollution had little effect. The internal CO2 and δ(13)C suggested that both water and N limited the net photosynthetic rate of street trees simultaneously, but water was more limiting. From these results, we concluded that the potential risk of hydraulic failure caused by climatic extremes could be low in urban street trees in temperate regions. However, the size of the safety margin might be different between species.

  14. Lake-level fluctuations since the Last Glaciation in Selin Co (lake), Central Tibet, investigated using optically stimulated luminescence dating of beach ridges

    International Nuclear Information System (INIS)

    This paper presents a preliminary study on lake-level fluctuations since the Last Glaciation in Selin Co (lake), Central Tibet, by dating four groups of beach ridges using optically stimulated luminescence (OSL). The highest/oldest beach ridge group (>100 m higher than the current lake level) is dated back to 67.9 ± 2.4 ka BP, corresponding to the early stage of the Last Glaciation (marine isotope stage (MIS) 4). This date further supports that no plateau-scale ice sheet covered the Tibetan Plateau during the Last Glaciation. The other three groups produce OSL ages of 30.4 ± 2.9 to 18.6 ± 1.7, 12.5 ± 1.6 to 9.2 ± 0.5, and 6.9 ± 0.2 ka BP respectively, most likely corresponding to cold or wet climate periods of the late stage of the Last Glaciation (MIS 2), deglaciation, and Holocene Hypsithermal. On the plateau scale, these four beach ridge groups are almost synchronous with advances or standstills of Himalayan glaciers, indicating similar climate controls across the central and southern Tibetan Plateau, and being consistent with the conclusion, obtained from nearby ice core records, that this area is affected by the South Asia monsoon. Furthermore, beach ridges are also synchronous with fluvial terraces in the northern Tibetan Plateau, implying common driving forces during their formation. Therefore, some terraces may be formed as a result of climate events rather than being of tectonic origin.

  15. Lake Fluctuation Effectively Regulates Wetland Evapotranspiration: A Case Study of the Largest Freshwater Lake in China

    Directory of Open Access Journals (Sweden)

    Xiaosong Zhao

    2014-08-01

    Full Text Available Lakes and wetlands provide valuable water resources. Wetland evapotranspiration (ET is a key hydrologic component; however, the effects of lake fluctuation on wetland ET remain unclear. The Poyang Lake is the largest freshwater lake in China and experiences a dramatic fluctuation in water level and inundated area. This study used remote sensing data to estimate the wetland ET for Poyang Lake and to illustrate the distribution of wetland ET and its response to lake fluctuations. Our results showed that wetland ET was related to lake fluctuation both spatially and temporally. Within the same year, the difference between annual water evaporation (Ewater and wetland ET (ETwetland was primarily attributed to lake fluctuation through its effects on inundated area and exposure days. A 1% increase in inundated area would result in a 7.87 ± 1.13 mm a−1 reduction in annual Ewater-to-ETwetland differences, and a 10-day elongation of exposure could lead to an 11.1 ± 1.6 mm a−1 increase in annual Ewater-to-ETwetland differences, on average. Inter-annually, the Ewater-to-ETwetland differences were attributed to the combined effects of atmospheric and environmental variables and lake fluctuation. The lake fluctuation contributed 73% to the inter-annual ET difference, followed by relative humidity (19%, net radiation (5%, and wind speed (4%. Overall, lake fluctuation effectively regulates wetland ET, and its effect should receive careful consideration in hydrological and water resources studies under the current changing climate.

  16. Holocene hydrological changes in south-western Mediterranean as recorded by lake-level fluctuations at Lago Preola, a coastal lake in southern Sicily, Italy

    Science.gov (United States)

    Magny, Michel; Vannière, Boris; Calo, Camilla; Millet, Laurent; Leroux, Aurélie; Peyron, Odile; Zanchetta, Gianni; La Mantia, Tommaso; Tinner, Willy

    2011-09-01

    This paper presents a high-resolution lake-level record for the Holocene at Lago Preola (Sicily, southern Italy) based on a specific sedimentological approach, with a chronology derived from AMS radiocarbon dates. It gives evidence of three major successive palaeohydrological periods, with (1) a pronounced dryness during the early Holocene until ca 10300 cal BP, (2) a highstand from ca 10300 to 4500 cal BP, and (3) a marked lowstand from 4500 cal BP to present. Large amplitude lake-level fluctuations characterise two transition phases at ca 10300-9000 and 6400-4500 cal BP. Period 2 was interrupted between 8300 and 7000 cal BP by a dry phase that was punctuated to ca 7300 cal BP by the deposition of a tephra from neighbouring Pantelleria Island. Comparisons of the Preola record with other palaeohydrological records along north-south and west-east transects in the Mediterranean show contrasting patterns of hydrological changes: north (south) of around 40°N latitude, the records highlight a mid-Holocene period characterised by lake-level minima (maxima). Humid mid-Holocene conditions over the Mediterranean south of 40°N were probably linked to a strong weakening of the Hadley cell circulation and of monsoon winds. We suggest that the maximum of humidity in the Mediterranean during the mid-Holocene was characterised by humid winters to the north of 40°N and humid summers to the south. On a multi-centennial scale, the high-resolution palaeohydrological reconstructions in the central Mediterranean area reveal a strong climate reversal around 4500-4000 cal BP, with contrasting changes in the hydrological cycle. In addition to seasonal and inter-hemispherical changes related to orbital forcing, this major oscillation might be related to non-linear responses of the climatic system to the gradual decrease in summer insolation at northern latitudes. Another major climate oscillation around 7500-7000 cal BP may have resulted from the combined effects of (1) a strong rate of

  17. A data set of worldwide glacier fluctuations

    OpenAIRE

    P. W. Leclercq; Oerlemans, J.; H. J. Basagic; I. Bushueva; Cook, A. J.; Le Bris, R.

    2014-01-01

    Glacier fluctuations contribute to variations in sea level and historical glacier length fluctuations are natural indicators of past climate change. To study these subjects, longterm information of glacier change is needed. In this paper we present a data set of global long-term glacier length fluctuations. The data set is a compilation of available information on changes in glacier length worldwide, including both measured and reconstructed glacier length fluctuations. All 471 length series ...

  18. Borehole Water Level Measurements in Kamchatka and Broadband Records of Very Large (M≧7.6) Earthquakes

    Science.gov (United States)

    Kasimova, V.; Kopylova, G.

    2010-12-01

    allowing for the variations of water level in the considered earthquakes were demonstrated. The comparison results of the amplitude-frequency content of maximum phase ground fluctuations with variations of water level allows us to isolate groups of the very large earthquakes that caused the different types of responses of water level in borehole UZ-5 on the seismic effects.

  19. Water Requirements for Food Assessed at Different Levels of Scale

    NARCIS (Netherlands)

    Ruiter de, Henri

    2012-01-01

    SUMMARY Fresh water scarcity is a major and increasing problem. Increasing water scarcity will have consequences for food security; thus strategies are needed to reduce the appropriation of water. Since agriculture uses 70% of all freshwater withdrawals,

  20. Evapotranspiration Partitioning and Response to Abnormally Low Water Levels in a Floodplain Wetland in China

    OpenAIRE

    Xiaosong Zhao; Yuanbo Liu

    2016-01-01

    Evapotranspiration (ET) is an important component of the wetland water budget. Water level declines in Poyang Lake, the largest freshwater lake in China, have caused concerns, especially during low water levels. However, how wetland ET and its partitioning respond to abnormally low water levels is unclear. In this study, wetland ET was estimated with MODIS data and meteorological data. The wetland ET partitioning and its relationship with abnormally low water levels were analyzed for 2000–201...

  1. Emergency action levels for light water reactors. Draft report

    International Nuclear Information System (INIS)

    United States nuclear power plants are currently preparing revised radiological emergency response plans. As part of these plans, each licensee is establishing plant-specific instrumentation readings, called emergency action levels (EALs), that indicate the presence of a problem and the need to declare one of four classes of emergency as designated by the U.S. Nuclear Regulatory Commission. In this report, the EALs prepared for a pressurized water reactor and a boiling water reactor are assessed to determine whether they meet the requirements of NUREG-0654, Rev. 1 Appendix 1. In addition, five recent nuclear incidents are studied to determine how their outcomes might have been affected by the new emergency response plans. Most of the EALs reviewed were judged adequate. In some cases, alternate EALs or sets of generic EALs are proposed to meet the intent of NUREG-0654 Rev 1 Appendix 1, and the wording of some of the initiating conditions for the four emergency classes is clarified. For three of the five incidents reviewed, the new emergency response plans probably would not have affected the outcome; in one case, the plans would probably have prevented core damage; and any effect on the outcome of the last incident is uncertain

  2. The Fluctuation Niche in Plants

    International Nuclear Information System (INIS)

    Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and eco physiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and inter annual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

  3. Multi-annual fluctuations in reconstructed historical time-series of a European lobster (Homarus gammarus) population disappear at increased exploitation levels.

    Science.gov (United States)

    Sundelöf, Andreas; Bartolino, Valerio; Ulmestrand, Mats; Cardinale, Massimiliano

    2013-01-01

    Through the history of ecology, fluctuations of populations have been a dominating topic, and endogenous causes of fluctuations and oscillations have been recognized and studied for more than 80 years. Here we analyzed an historical dataset, covering more than 130 years, of European lobster (Homarus gammarus) catches. The data shows periodic fluctuations, which are first dampened and then disappear over time. The disappearance of the periodicity coincided with a substantial increase in fishing effort and the oscillations have not reappeared in the time series. The shifting baseline syndrome has changed our perception of not only the status of the stock, but also the regulating pressures. We describe the transition of a naturally regulated lobster population into a heavily exploited fisheries controlled stock. This is shown by the incorporation of environmental and endogenous processes in generalized additive models, autocorrelation functions and periodicity analyses of time-series. PMID:23573187

  4. Multi-annual fluctuations in reconstructed historical time-series of a European lobster (Homarus gammarus population disappear at increased exploitation levels.

    Directory of Open Access Journals (Sweden)

    Andreas Sundelöf

    Full Text Available Through the history of ecology, fluctuations of populations have been a dominating topic, and endogenous causes of fluctuations and oscillations have been recognized and studied for more than 80 years. Here we analyzed an historical dataset, covering more than 130 years, of European lobster (Homarus gammarus catches. The data shows periodic fluctuations, which are first dampened and then disappear over time. The disappearance of the periodicity coincided with a substantial increase in fishing effort and the oscillations have not reappeared in the time series. The shifting baseline syndrome has changed our perception of not only the status of the stock, but also the regulating pressures. We describe the transition of a naturally regulated lobster population into a heavily exploited fisheries controlled stock. This is shown by the incorporation of environmental and endogenous processes in generalized additive models, autocorrelation functions and periodicity analyses of time-series.

  5. GPS water level measurements for Indonesia's Tsunami Early Warning System

    Science.gov (United States)

    Schöne, T.; Pandoe, W.; Mudita, I.; Roemer, S.; Illigner, J.; Zech, C.; Galas, R.

    2011-03-01

    On Boxing Day 2004, a severe tsunami was generated by a strong earthquake in Northern Sumatra causing a large number of casualties. At this time, neither an offshore buoy network was in place to measure tsunami waves, nor a system to disseminate tsunami warnings to local governmental entities. Since then, buoys have been developed by Indonesia and Germany, complemented by NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) buoys, and have been moored offshore Sumatra and Java. The suite of sensors for offshore tsunami detection in Indonesia has been advanced by adding GPS technology for water level measurements. The usage of GPS buoys in tsunami warning systems is a relatively new approach. The concept of the German Indonesian Tsunami Early Warning System (GITEWS) (Rudloff et al., 2009) combines GPS technology and ocean bottom pressure (OBP) measurements. Especially for near-field installations where the seismic noise may deteriorate the OBP data, GPS-derived sea level heights provide additional information. The GPS buoy technology is precise enough to detect medium to large tsunamis of amplitudes larger than 10 cm. The analysis presented here suggests that for about 68% of the time, tsunamis larger than 5 cm may be detectable.

  6. Global Anthropogenic Phosphorus Loads to Fresh Water, Grey Water Footprint and Water Pollution Levels: A High-Resolution Global Study

    Science.gov (United States)

    Mekonnen, M. M.; Hoekstra, A. Y. Y.

    2014-12-01

    We estimated anthropogenic phosphorus (P) loads to freshwater, globally at a spatial resolution level of 5 by 5 arc minute. The global anthropogenic P load to freshwater systems from both diffuse and point sources in the period 2002-2010 was 1.5 million tonnes per year. China contributed about 30% to this global anthropogenic P load. India was the second largest contributor (8%), followed by the USA (7%), Spain and Brazil each contributing 6% to the total. The domestic sector contributed the largest share (54%) to this total followed by agriculture (38%) and industry (8%). Among the crops, production of cereals had the largest contribution to the P loads (32%), followed by fruits, vegetables, and oil crops, each contributing about 15% to the total. We also calculated the resultant grey water footprints, and relate the grey water footprints per river basin to runoff to calculate the P-related water pollution level (WPL) per catchment.

  7. Water Quality and Hydrology of Whitefish (Bardon) Lake, Douglas County, Wisconsin, With Special Emphasis on Responses of an Oligotrophic Seepage Lake to Changes in Phosphorus Loading and Water Level

    Science.gov (United States)

    Robertson, Dale M.; Rose, William J.; Juckem, Paul F.

    2009-01-01

    average annual load of phosphorus to the lake was 232 pounds: 56 percent from precipitation, 27 percent from groundwater, and 16 percent from septic systems. During a series of dry years (low water levels) and wet years (high water levels), the inputs of water and phosphorus ranged by only 10-13 percent. Results from the Canfield and Bachmann eutrophication model and Carlson trophic-state-index equations demonstrated that the lake directly responds to changes in external phosphorus loading, with percent change in chlorophyll a being similar to the percent change in loading and the change in total phosphorus and Secchi depth being slightly smaller. Therefore, changes in phosphorus loading should affect the water quality of the lake. Specific scenarios that simulated the effects of anthropogenic (human-induced) and climatic (water level) changes demonstrated that: surface-water inflow (runoff) based on current development has little effect on pelagic water quality, changes in the inputs from septic systems and development in the watershed could have a large effect on water quality, and decreases in water and phosphorus loading during periods of low water level had little effect on water quality. Sustained high water levels, resulting from several wet years with relatively high water and phosphorus input, however, could cause a small degradation in water quality. Although high water levels may be associated with a degradation in water quality, it appears that anthropogenic changes in the watershed may be more important in affecting the future water quality of the lake. Fluctuations in water levels since 1998 are representative of what has occurred since 1900, with fluctuations of about 3 feet occurring about every 15 years. Based on total phosphorus concentrations inferred from sediment core analysis, there has been little long-term change in water quality and there has been a slight deterioration in water quality following most periods of high water levels. There

  8. Effects of sea-level rise on ground water flow in a coastal aquifer system

    Science.gov (United States)

    Masterson, J.P.; Garabedian, S.P.

    2007-01-01

    The effects of sea-level rise on the depth to the fresh water/salt water interface were simulated by using a density-dependent, three-dimensional numerical ground water flow model for a simplified hypothetical fresh water lens that is similar to shallow, coastal aquifers found along the Atlantic coast of the United States. Simulations of sea-level rise of 2.65 mm/year from 1929 to 2050 resulted in an increase in water levels relative to a fixed datum, yet a net decrease in water levels relative to the increased sea-level position. The net decrease in water levels was much greater near a gaining stream than farther from the stream. The difference in the change in water levels is attributed to the dampening effect of the stream on water level changes in response to sea-level rise. In response to the decreased water level altitudes relative to local sea level, the depth to the fresh water/salt water interface decreased. This reduction in the thickness of the fresh water lens varied throughout the aquifer and was greatly affected by proximity to a ground water fed stream and whether the stream was tidally influenced. Away from the stream, the thickness of the fresh water lens decreased by about 2% from 1929 to 2050, whereas the fresh water lens thickness decreased by about 22% to 31% for the same period near the stream, depending on whether the stream was tidally influenced. The difference in the change in the fresh water/salt water interface position is controlled by the difference in the net decline in water levels relative to local sea level. ?? 2007 National Ground Water Association.

  9. Evapotranspiration Partitioning and Response to Abnormally Low Water Levels in a Floodplain Wetland in China

    Directory of Open Access Journals (Sweden)

    Xiaosong Zhao

    2016-01-01

    Full Text Available Evapotranspiration (ET is an important component of the wetland water budget. Water level declines in Poyang Lake, the largest freshwater lake in China, have caused concerns, especially during low water levels. However, how wetland ET and its partitioning respond to abnormally low water levels is unclear. In this study, wetland ET was estimated with MODIS data and meteorological data. The wetland ET partitioning and its relationship with abnormally low water levels were analyzed for 2000–2013. The results showed that the water evaporation rate (Ewater was larger than the land ET rate (ETland; the ETland/Ewater ranged from 0.77 to 0.99. When the water level was below 12.8 m, the ET partition ratio was larger than 1, which indicates that wetland ET comes from land surface ET more than water evaporation. The negative standardized water level index (SWI was used to represent an abnormally low water level in the wetland. Although the monthly wetland ET decreased as the negative SWI decreased, ETland was higher than the average under negative SWI conditions from September to December, when the water level decreased. The abnormally low water level induced more water loss from the land surface, especially when the water level decreased, which reduced the available water resources along the wetland shore.

  10. Water-level predictions for Indian Wells Valley ground-water basin, California, 1978

    Science.gov (United States)

    Mallory, Michael J.

    1979-01-01

    Ground-water pumpage in Indian Wells Valley, virtually a closed basin in the Mojave Desert of southern California, has increased gradually since 1945 and presently exceeds the long-term mean annual recharge (perennial supply). In order to aid in the understanding and management of the ground-water basin, a digital ground-water model was constructed by the U.S. Geological Survey. Since the original development of this model, conditions in the basin, including areal distribution and rates of ground-water pumpage, have changed. The results of simulation for the period 1969-76 constitute a second verification of the original model. Calculated heads for 1976 agree with the observed heads, indicating a good calibration of the original model. A predictive simulation for the period 1977-2020 used pumpage values increasing from about 15,500 acre-feet per year to about 26,000 acre-feet per year. The pumpage used in this report reflects a slightly slower growth rate and a more concentrated pattern of development than that investigated when the model was originally developed. The effects of this pattern of pumpage are reflected in the water levels simulated by the model. Predicted drawdowns for 1983 are less extensive but locally more severe than those predicted earlier. The reversal of the hydraulic gradient between China Lake playa and the city of Ridgecrest, as produced by these drawdowns by the year 2020, suggests that the water-quality effects of such drawdowns should be investigated, as this could result in inferior water from the China Lake playa area flowing southward into areas of withdrawal. (Woodard-USGS)

  11. Borehole Geophysical, Water-Level, and Water-Quality Investigation of a Monitoring Well Completed in the St. Francois Aquifer in Oregon County, Missouri, 2005-08

    Science.gov (United States)

    Schumacher, John G.; Kleeschulte, Michael J.

    2010-01-01

    A deep (more than 2,000 feet) monitoring well was installed in an area being explored for lead and zinc deposits within the Mark Twain National Forest in southern Missouri. The area is a mature karst terrain where rocks of the Ozark aquifer, a primary source of water for private and public supplies and major springs in the nearby Eleven Point National Wild and Scenic River and the Ozark National Scenic Riverways, are exposed at the surface. The potential lead deposits lie about 2,000 feet below the surface within a deeper aquifer, called the St. Francois aquifer. The two aquifers are separated by the St. Francois confining unit. The monitoring well was installed as part of a series of investigations to examine potentiometric head relations and water-quality differences between the two aquifers. Results of borehole flowmeter measurements in the open borehole and water-level measurements from the completed monitoring well USGS-D1 indicate that a seasonal upward gradient exists between the St. Francois aquifer and the overlying Ozark aquifer from about September through February. The upward potentiometric heads across the St. Francois confining unit that separates the two aquifers averaged 13.40 feet. Large reversals in this upward gradient occurred during the late winter through summer (about February through August) when water levels in the Ozark aquifer were as much as 138.47 feet higher (average of 53.84 feet) than water levels in the St. Francois aquifer. Most of the fluctuation of potentiometric gradient is caused by precipitation and rapid recharge that cause large and rapid increases in water levels in the Ozark aquifer. Analysis of water-quality samples collected from the St. Francois aquifer interval of the monitoring well indicated a sodium-chloride type water containing dissolved-solids concentrations as large as 1,300 milligrams per liter and large concentrations of sodium, chloride, sulfate, boron, and lithium. In contrast, water in the overlying Ozark

  12. Material Weakening of Slip Zone Soils Induced by Water Level Fluctuation in the Ancient Landslides of Three Gorges Reservoir

    Directory of Open Access Journals (Sweden)

    Yu-Yong Jiao

    2014-01-01

    Full Text Available This experimental study investigated the effect of repeated wetting and drying on the reduction of slip zone soils taken from the Huangtupo landslide in the Three Gorges Reservoir, China. The variation process of the physical property and substance composition of the slip zone soils under the wetting-drying cycles was studied through liquid and plastic limit test and X-ray diffraction test. The results indicate that (1 the shearing strength of the slip zone soil dramatically decreased after one wetting-drying cycle and then gradually decreased until reaching a relatively stable state at the fourth cycle; (2 the plasticity index of the slip zone soil varied with increasing number of cycles and a variation process opposite to that of the strength value was observed; and (3 the clay mineral content in the slip zone soil increased and the calcite and quartz contents relatively decreased with increasing number of cycles. The variations in the plasticity index of the slip zone soil, as well as the increase in its clay mineral content, play important roles in the strength reduction. The results of this study provide a foundation for revealing the deformation and damage mechanism of landslides in reservoir banks.

  13. DOC and CO2-C Releases from Pristine and Drained Peat Soils in Response to Water Table Fluctuations: A Mesocosm Experiment

    Directory of Open Access Journals (Sweden)

    Merjo P. P. Laine

    2014-01-01

    Full Text Available Hydrological conditions are considered to be among the main drivers influencing the export of dissolved organic carbon (DOC from terrestrial to aquatic ecosystems, and hydrology is likely to alter due to climate change. We built a mesocosm experiment by using peat profiles from a pristine and from a drained (drained in 1978 peatland. A several-week-long low water table period followed by a high water table period, that is, a setting mimicking drought followed by flood, released relatively more DOC from pristine peat than from drained peat. From pristine peat profiles DOC was released into soil water in such quantities that the concentration of DOC remained stable despite dilution caused by added spring water to the mesocosms. In drained peat the DOC concentrations decreased during the high water table period indicating stronger dilution effect in comparison to pristine peat. At the landscape level DOC load from a drained peatland to the recipient water body may, however, increase during flooding because of high water runoff out of the peatland containing high DOC concentrations relative to the forest and agricultural areas. During the high water table period neither peat type nor water table had any clear impact on carbon dioxide (CO2-C fluxes.

  14. Wave transformation and shoreline water level on Funafuti Atoll, Tuvalu

    Science.gov (United States)

    Beetham, Edward; Kench, Paul S.; O'Callaghan, Joanne; Popinet, Stéphane

    2016-01-01

    The influence of sea swell (SS) waves, infragravity (IG) waves, and wave setup on maximum runup (Rmax) is investigated across different tidal stages on Fatato Island, Funafuti Atoll, Tuvalu. Field results illustrate that SS waves are tidally modulated at the shoreline, with comparatively greater wave attenuation and setup occurring at low tide versus high tide. A shoreward increase in IG wave height is observed across the 100 m wide reef flat at all tidal elevations, with no tidal modulation of IG wave height at the reef flat or island shoreline. A 1-D shock-capturing Green-Naghdi solver is used to replicate the field deployment and analyze Rmax. Model outputs for SS wave height, IG wave height and setup at the shoreline match field results with model skill >0.96. Model outputs for Rmax are used to identify the temporal window when geomorphic activity can occur on the beach face. During periods of moderate swell energy, waves can impact the beach face at spring low tide, due to a combination of wave setup and strong IG wave activity. Under mean wave conditions, the combined influence of setup, IG waves and SS waves results in interaction with island sediment at midtide. At high tide, SS and IG waves directly impact the beach face. Overall, wave activity is present on the beach face for 71% of the study period, a significantly longer duration than is calculated using mean water level and topographic data.

  15. ERPWS: An Energy Efficient Routing Protocol for Conductive Sensor based Water Level Monitoring and Control System using Zigbee and 74HC14 Inverter

    Directory of Open Access Journals (Sweden)

    Saima Maqbool

    2013-07-01

    Full Text Available In this paper we have shown how to use conductive sensor, Zigbee and 74HC14 Inverter to monitor the water level and to control the working of pump. This project is designed to automatically fill the over head tank when it gets empty and monitor the water level in it. The motor is switched ON when the water level in the overhead tank drops below a pre fixed low level (on point and puts off the motor when water level rises up to pre fixed high level (off point.The motor is also switched off during the following conditions: when the sump water is exhausted before filling overhead tank, pump running dry, mains voltage fluctuations. We also introduce an energy efficient routing protocol for Wireless Sensor Networks (ERPWS for Conductive Sensor based Water Level Monitoring and Control System using Zigbee (XBEE 802.15.4 in terms of energy consumptions, the packet loss ratio, network lifetime and the average delivery delay. The XBEE used here is XBEE Pro Series 1(XBP24-AWI-001 and IC used is 74HC14 Hex Inverting Schmitt trigger. Simulation results have been obtained by using NS2 simulator. The evaluation results show that the energy consumption of routing using ERPWS is significantly lower than LEACH and traditional routing protocols.

  16. COMPARISON OF VENTED AND ABSOLUTE PRESSURE TRANSDUCERS FOR WATER-LEVEL MONITORING IN HANFORD SITE CENTRAL PLATEAU WELLS

    Energy Technology Data Exchange (ETDEWEB)

    MCDONALD JP

    2011-09-08

    Automated water-level data collected using vented pressure transducers deployed in Hanford Site Central Plateau wells commonly display more variability than manual tape measurements in response to barometric pressure fluctuations. To explain this difference, it was hypothesized that vented pressure transducers installed in some wells are subject to barometric pressure effects that reduce water-level measurement accuracy. Vented pressure transducers use a vent tube, which is open to the atmosphere at land surface, to supply air pressure to the transducer housing for barometric compensation so the transducer measurements will represent only the water pressure. When using vented transducers, the assumption is made that the air pressure between land surface and the well bore is in equilibrium. By comparison, absolute pressure transducers directly measure the air pressure within the wellbore. Barometric compensation is achieved by subtracting the well bore air pressure measurement from the total pressure measured by a second transducer submerged in the water. Thus, no assumption of air pressure equilibrium is needed. In this study, water-level measurements were collected from the same Central Plateau wells using both vented and absolute pressure transducers to evaluate the different methods of barometric compensation. Manual tape measurements were also collected to evaluate the transducers. Measurements collected during this study demonstrated that the vented pressure transducers over-responded to barometric pressure fluctuations due to a pressure disequilibrium between the air within the wellbores and the atmosphere at land surface. The disequilibrium is thought to be caused by the relatively long time required for barometric pressure changes to equilibrate between land surface and the deep vadose zone and may be exacerbated by the restriction of air flow between the well bore and the atmosphere due to the presence of sample pump landing plates and well caps. The

  17. 时变补给条件下河渠间潜水的一维非稳定运动%Water Table Fluctuation Between Two Parallel Ditches Induced by Time-varying Recharge

    Institute of Scientific and Technical Information of China (English)

    夏强; 许模; 邓英尔; 李晓

    2015-01-01

    Taking account of exponentially and periodically time-varying recharge,water table fluctuation be-tween two parallel ditches was studied.The analytical solution was derived based on the first linearization method of Boussinesq equation,and Duhamel principle.This paper analyzed the characteristics of phreatic water move-ment by using three kinds of recharge rate functions including exponent-increase,exponent-decay,and sine func-tion.In the first case,water table rises monotonously with the increasing recharge rate;and watershed between the two ditches moves from the higher level side towards the other sides,but will never cross the middle line of the aquifer.In the exponent-decay case,water table goes up at the beginning,then falls after reaching a peak value;watershed firstly moves towards the middle of the aquifer,then turns back to the higher level side due to the decli-ning recharge rate.In the last case,water table periodically fluctuates corresponding to the sine function recharge;and there is a significant time lag between the stimulator and the respond;watershed sways back and forth between the higher level ditch and the middle of the aquifer.The results can be a clue to study the response of groundwater system to climate change,in addition to the transition rule between surface and ground water.%针对河渠间潜水的一维非稳定运动,考虑了补给强度的时变性,根据Boussinesq方程的第一线性化方法,应用Duhamel原理得到了方程的解析解,进一步得出补给强度为指数函数和三角函数的潜水位计算公式。通过算例分析补给强度指数增加、指数衰减和正弦函数变化条件下潜水面的变化特征,指数增加条件下潜水位单调增加,分水岭从高水位一侧向河间地块中部移动;指数衰减条件下潜水位先增大,后减小,具有一个峰值,分水岭先从高水位一侧向河间地块中部移动,之后随补给强度减弱返回到高水位河渠;

  18. 锅炉汽包水位波动成因分析及解决方案%The Reason and Solution of Boiler Steam Drum Water Fluctuation

    Institute of Scientific and Technical Information of China (English)

    刘亚坤

    2011-01-01

    中冶京诚(营口)中试基地锅炉房为全厂生产提供蒸汽保障.其中3台国产锅炉存在汽包水位控制问题,经常造成锅炉误动作停炉,影响生产.提出了一种解决方案,即利用现有设备,调整自动化系统多个参数及相关工艺过程.改造后,既节约了资金,又保证了锅炉生产稳定,创造了长期的经济效益.%CERI Yingkou Equipment Development and Manufacturing Co. , Ltd boiler factory supply steam for manufacture. The boiler factory has 4 boilers now, 3 of them are made in China, they has some problems at steam drum water fluctuation. Sometimes its cause the boiler emergency stop. The essay discuss one of the solution that use the existing equipment. The solution only adjust some parameter of automatic system and change some process engineering . Using this solution not only save the money but insure the boiler steady running. Long time economic benefits is gained.

  19. Dual-Level Material and Psychological Assessment of Urban Water Security in a Water-Stressed Coastal City

    OpenAIRE

    Yajing Huang; Linyu Xu; Hao Yin; YanpengCai; ZhifengYang

    2015-01-01

    The acceleration of urbanization and industrialization has been gradually aggravating water security issues, such as water shortages, water pollution, and flooding or drought disasters and so on. Water security issues have become a great challenge to urban sustainable development. In this context, we proposed a dual-level material and psychological assessment method to assess urban water security. Psychological security coefficients were introduced in this method to combine material security ...

  20. Ground-water levels and directions of flow in Geauga County, Ohio, September 1994, and changes in ground-water levels, 1986-94

    Science.gov (United States)

    Jagucki, M.L.; Lesney, L.L.

    1995-01-01

    This report presents the results of a study by the U.S. Geological Survey, in cooperation with Geauga County Planning Commission and Board of County Commissioners, to determine directions of ground-water flow and to assess differences from 1986 to 1994 in ground-water levels in the glacial deposits and Pottsville Formation, Cuyahoga Group, and the Berea Sandstone. Water levels were measured in 219 wells in Geauga County, Ohio, in September 1994. Water levels measured in January and February 1986 in 88 of the 219 wells were used for comparison. Water-level maps constructed from measurements made in September 1994 to show that ground-water levels in the Pottsville Formation and the glacial deposits generally correspond to the land-surface configuration and that ground water flows from the uplands to adjacent streams and buried valleys. Ground-water flow in the Cuyahoga Group is generally downward from the Pottsville Formation to the Berea Sandstone. Directions of ground-water flow in the Berea Sandstone are toward outcrop areas at the north and east edges of Geauga County and toward sub-crops beneath buried glacial valley deposits in Chardon, Chester, Munson, and Russel Townships and along the west edge of the county. A comparison of water level measurements in 1986 and 1994 indicates that water levels declined in 70 percent of the measured wells and increased in 30 percent. The change in water levels from 1986 to 1994 ranged from an increase of 13.58 feet to a decrease of 29.25 feet. Thirty percent of all water-level changes were less than 1 foot in magnitude. In nearly 80 percent of the wells, water-level changes were within the range of plus or minus 5 feet. Among the wells for which two or more historical measurements were available, the 1994 water levels in 54 percent were outside the range of water-levels observed in previous studies (only 24 percent were greater than 1 foot outside of the previously-observed range). Water-level declines of greater than 10 feet

  1. Hormones and clocks: do they disrupt the locks? Fluctuating estrogen levels during menopausal transition may influence clock genes and trigger chronic telogen effluvium.

    Science.gov (United States)

    Mirmirani, Paradi

    2016-01-01

    Chronic telogen effluvium describes the clinical condition noted mostly in middle-aged women of increased, diffuse scalp hair shedding that is prolonged and often presents with a fluctuating course that may continue for years but does not lead to visible hair thinning. Despite its description almost 20 years ago, the underlying pathologic cause of CTE is yet to be identified. However the culmination of research in the field of hair biology and the burgeoning field of chronobiology may lead to exciting breakthroughs in our understanding of CTE. In this paper the current literature on CTE is reviewed and a hypothesis is put forth that CTE may be triggered by hormonal fluctuations and alterations in circadian control genes. PMID:27617515

  2. Records of wells, ground-water levels, and ground-water withdrawals in the lower Goose Creek Basin, Cassia County, Idaho

    Science.gov (United States)

    Mower, R.W.

    1954-01-01

    Investigations by the United States Geological Survey of Ground Water in the Southern border area of the Snake Rive Plain, south of the Snake River, a re concerned at the present time with delineation of the principal ground-water districts, the extent and location of existing ground-water developments, the possibilities for additional development, and the effects of ground-water development on the regimen of streams and reservoirs whose waters are appropriate for beneficial use. The lower part of the Goose Creek Basin is one of the important ground-water districts of the southern plains area and there are substantial but spotty developments of ground water for irrigation in the basin. Several thousand irrigable acres that are now dry could be put under irrigation if a dependable supply of ground water could be developed. The relations of the ground-water reservoirs to the regime of the Snake River and Goose Cree, and to the large body of ground water in the Snake River Plain north of the Snake, are poorly known. A large amount of geologic and hydrologic study remains to be done before those relations can be accurately determined. Investigations will be continued in the future but file work and preparation of a comprehensive report inevitably will be delayed. Therefore the available records are presented herein in order to make them accessible to farmers, well drillers, government agencies, and the general public. Interpretation of the records is not attempted in this report and is deferred pending the accumulation of additional and quantitative information. The data summarized herein include records of the locations and physical characteristics of wells, the depth to water in wells, fluctuations of water levels in observation wells, and estimated rates and volumes of seasonal ans yearly ground-water pumpage for irrigation, municipal, and other uses. This information is complete for work done as of December 31, 1952. The investigations upon which this report is

  3. Characterisation of Culex quinquefasciatus (Diptera: Culicidae larval habitats at ground level and temporal fluctuations of larval abundance in Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Marta Grech

    2013-09-01

    Full Text Available The aims of this study were to characterise the ground-level larval habitats of the mosquito Culex quinquefasciatus, to determine the relationships between habitat characteristics and larval abundance and to examine seasonal larval-stage variations in Córdoba city. Every two weeks for two years, 15 larval habitats (natural and artificial water bodies, including shallow wells, drains, retention ponds, canals and ditches were visited and sampled for larval mosquitoes. Data regarding the water depth, temperature and pH, permanence, the presence of aquatic vegetation and the density of collected mosquito larvae were recorded. Data on the average air temperatures and accumulated precipitation during the 15 days prior to each sampling date were also obtained. Cx. quinquefasciatus larvae were collected throughout the study period and were generally most abundant in the summer season. Generalised linear mixed models indicated the average air temperature and presence of dicotyledonous aquatic vegetation as variables that served as important predictors of larval densities. Additionally, permanent breeding sites supported high larval densities. In Córdoba city and possibly in other highly populated cities at the same latitude with the same environmental conditions, control programs should focus on permanent larval habitats with aquatic vegetation during the early spring, when the Cx. quinquefasciatus population begins to increase.

  4. Behaviors of extreme water level in the Pearl River Delta and possible impacts from human activities

    Directory of Open Access Journals (Sweden)

    Y. D. Chen

    2007-12-01

    Full Text Available Trends and variations of the extreme water levels defined as exceeding/falling below certain thresholds (mean ± std across the Pearl River Delta (PRD are systematically explored using the linear regression method. Research results indicate that: 1 The upper PRD is dominated by the significant decreasing low water level, and significant increasing low water level can be identified in the lower PRD. The variations of the relative frequency of the high water level are characterized by the decreasing variability in the middle PRD. However more stations show significant changes of the relative frequency of the low water level across the PRD. No confirmative changing patterns of the relative frequency of the low water level can be detected in the middle PRD; 2 When it comes to the seasonal variations of the high/low water level in JJA (high flow periods in the PRD, stations located closer to the estuary tend to exhibit increasing high/low water level. However stations located closer to the upper PRD tend to show decreasing high/low water level. Similar patterns can be identified in the high/low water level in DJF (low flow periods in the PRD; 3 The changes of the water level in the PRD are heavily affected by human interferences, e.g. in-channel dredging, sand mining and the construction of levees. The stations dominated by decreasing water level are mostly located along the river channels featured by highly-intensive dredging. The stations along the coastal regions show significant increasing extreme high/low water level. The coastal regions are not influenced by in-channel dredging, and furthermore, sediment loads from upper and middle PRD are deposited in the river mouths and which will tend to raise the water level in the estuary of the PRD. The findings of this paper may be helpful for local water resource management.

  5. Consequences of seasonal variation in reservoir water level for predatory fishes: linking visual foraging and prey densities

    Science.gov (United States)

    Klobucar, Stephen L.; Budy, Phaedra

    2016-01-01

    In reservoirs, seasonal drawdown can alter the physical environment and may influence predatory fish performance. We investigated the performance of lake trout (Salvelinus namaycush) in a western reservoir by coupling field measurements with visual foraging and bioenergetic models at four distinct states (early summer, mid-summer, late summer, and fall). The models suggested that lake trout prey, juvenile kokanee (Oncorhynchus nerka), are limited seasonally by suitable temperature and dissolved oxygen. Accordingly, prey densities were greatest in late summer when reservoir volume was lowest and fish were concentrated by stratification. Prey encounter rates (up to 68 fish·day−1) and predator consumption are also predicted to be greatest during late summer. However, our models suggested that turbidity negatively correlates with prey detection and consumption across reservoir states. Under the most turbid conditions, lake trout did not meet physiological demands; however, during less turbid periods, predator consumption reached maximum bioenergetic efficiency. Overall, our findings demonstrate that rapid reservoir fluctuations and associated abiotic conditions can influence predator–prey interactions, and our models describe the potential impacts of water level fluctuation on valuable sport fishes.

  6. Core level spectroscopy of neon- and water-clusters

    International Nuclear Information System (INIS)

    We present high resolution K-shell absorption spectra of neon and water clusters from the monomer to the solid. Shifts in the pre edge absorption are discussed and first EXAFS data presented. For water clusters a photoelectron study supplements the results. (author)

  7. Fluctuations at electrode-YSZ interfaces

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Hansen, Karin Vels; Skou, Eivind

    2005-01-01

    . At temperatures below 900$^\\circ$C the fluctuations cease. At LSM oxygen electrodes and Ni hydrogen electrodes the fluctuations are similar in amplitude and frequency, but the characteristic shape is not observed. Also some spectacular, but not easily reproduced, observations on Ni electrodes in hydrogen/water...

  8. Study of electric and magnetic field fluctuations from lower hybrid drift instability waves in the terrestrial magnetotail with the fully kinetic, semi-implicit, adaptive multi level multi domain method

    Science.gov (United States)

    Innocenti, M. E.; Norgren, C.; Newman, D.; Goldman, M.; Markidis, S.; Lapenta, G.

    2016-05-01

    The newly developed fully kinetic, semi-implicit, adaptive multi-level multi-domain (MLMD) method is used to simulate, at realistic mass ratio, the development of the lower hybrid drift instability (LHDI) in the terrestrial magnetotail over a large wavenumber range and at a low computational cost. The power spectra of the perpendicular electric field and of the fluctuations of the parallel magnetic field are studied at wavenumbers and times that allow to appreciate the onset of the electrostatic and electromagnetic LHDI branches and of the kink instability. The coupling between electric and magnetic field fluctuations observed by Norgren et al. ["Lower hybrid drift waves: Space observations," Phys. Rev. Lett. 109, 055001 (2012)] for high wavenumber LHDI waves in the terrestrial magnetotail is verified. In the MLMD simulations presented, a domain ("coarse grid") is simulated with low resolution. A small fraction of the entire domain is then simulated with higher resolution also ("refined grid") to capture smaller scale, higher frequency processes. Initially, the MLMD method is validated for LHDI simulations. MLMD simulations with different levels of grid refinement are validated against the standard semi-implicit particle in cell simulations of domains corresponding to both the coarse and the refined grid. Precious information regarding the applicability of the MLMD method to turbulence simulations is derived. The power spectra of MLMD simulations done with different levels of refinements are then compared. They consistently show a break in the magnetic field spectra at k⊥di˜30 , with di the ion skin depth and k⊥ the perpendicular wavenumber. The break is observed at early simulated times, Ωcit <6 , with Ωci the ion cyclotron frequency. It is due to the initial decoupling of electric and magnetic field fluctuations at intermediate and low wavenumbers, before the development of the electromagnetic LHDI branch. Evidence of coupling between electric and magnetic

  9. Environmental factors responsible for fluctuation phenomena. Difficulties in accepting these facts by scientific community

    International Nuclear Information System (INIS)

    Our physico-chemical approach started already in early sixties by Piccardi is based on the sensitivity of water to low level of energy of physical factors excising and fluctuating in the environment. This approach could be at the origin of many unexplained solar-terrestrial relationships or fluctuating phenomena in biology, medicine, psychology and social sciences. Methodology and causality are still the major problems raised in the scientific community by the Piccardi effect. These problems can be solved only by the organization of interdisciplinary cooperation in the research and scientific investigation of environmental factors responsible for fluctuating phenomena in exact, natural and human sciences on an international scale. 9 refs

  10. Comparison of Regression Methods to Compute Atmospheric Pressure and Earth Tidal Coefficients in Water Level Associated with Wenchuan Earthquake of 12 May 2008

    Science.gov (United States)

    He, Anhua; Singh, Ramesh P.; Sun, Zhaohua; Ye, Qing; Zhao, Gang

    2016-07-01

    The earth tide, atmospheric pressure, precipitation and earthquake fluctuations, especially earthquake greatly impacts water well levels, thus anomalous co-seismic changes in ground water levels have been observed. In this paper, we have used four different models, simple linear regression (SLR), multiple linear regression (MLR), principal component analysis (PCA) and partial least squares (PLS) to compute the atmospheric pressure and earth tidal effects on water level. Furthermore, we have used the Akaike information criterion (AIC) to study the performance of various models. Based on the lowest AIC and sum of squares for error values, the best estimate of the effects of atmospheric pressure and earth tide on water level is found using the MLR model. However, MLR model does not provide multicollinearity between inputs, as a result the atmospheric pressure and earth tidal response coefficients fail to reflect the mechanisms associated with the groundwater level fluctuations. On the premise of solving serious multicollinearity of inputs, PLS model shows the minimum AIC value. The atmospheric pressure and earth tidal response coefficients show close response with the observation using PLS model. The atmospheric pressure and the earth tidal response coefficients are found to be sensitive to the stress-strain state using the observed data for the period 1 April-8 June 2008 of Chuan 03# well. The transient enhancement of porosity of rock mass around Chuan 03# well associated with the Wenchuan earthquake (Mw = 7.9 of 12 May 2008) that has taken its original pre-seismic level after 13 days indicates that the co-seismic sharp rise of water well could be induced by static stress change, rather than development of new fractures.

  11. Molecular level water and solute transport in reverse osmosis membranes

    Science.gov (United States)

    Lueptow, Richard M.; Shen, Meng; Keten, Sinan

    2015-11-01

    The water permeability and rejection characteristics of six solutes, methanol, ethanol, 2-propanol, urea, Na+, and Cl-, were studied for a polymeric reverse osmosis (RO) membrane using non-equilibrium molecular dynamics simulations. Results indicate that water flux increases with an increasing fraction of percolated free volume in the membrane polymer structure. Solute molecules display Brownian motion and hop from pore to pore as they pass through the membrane. The solute rejection depends on both the size of the solute molecule and the chemical interaction of the solute with water and the membrane. When the open spaces in the polymeric structure are such that solutes have to shed at least one water molecule from their solvation shell to pass through the membrane molecular structure, the water-solute pair interaction energy governs solute rejection. Organic solutes more easily shed water molecules than ions to more readily pass through the membrane. Hydrogen-bonding sites for molecules like urea also lead to a higher rejection. These findings underline the importance of the solute's solvation shell and solute-water-membrane chemistry in solute transport and rejection in RO membranes. Funded by the Institute for Sustainability and Energy at Northwestern with computing resources from XSEDE (NSF grant ACI-1053575).

  12. Options for water-level control in developed wetlands

    Science.gov (United States)

    Kelley, J. R., Jr.; Laubhan, M. K.; Reid, F. A.; Wortham, J. S.; Fredrickson, L. H.

    1993-01-01

    Wetland habitats in the United States currently are lost at a rate of 260,000 acres/year (105,218 ha/year). Consequently, water birds concentrate in fewer and smaller areas. Such concentrations may deplete food supplies and influence behavior, physiology, and survival. Continued losses increase the importance of sound management of the remaining wetlands because water birds depend on them. Human activities modified the natural hydrology of most remaining wetlands in the conterminous United States, and such hydrologic alterations frequently reduce wetland productivity. The restoration of original wetland functions and productivity often requires the development of water distribution and discharge systems to emulate natural hydrologic regimes. Construction of levees and correct placement of control structures and water-delivery and water-discharge systems are necessary to (1) create soil and water conditions for the germination of desirable plants, (2) control nuisance vegetation, (3) promote the production of invertebrates, and (4) make foods available for wildlife that depends of wetlands (Leaflets 13.2.1 and 13.4.6). This paper provides basic guidelines for the design of wetlands that benefit wildlife. If biological considerations are not incorporated into such designs, the capability of managing wetlands for water birds is reduced and costs often are greater. Although we address the development of palustrine wetlands in migration and wintering areas, many of the discussed principles are applicable to the development of other wetland types and in other locations.

  13. Investigation of spatio-temporal water level and mass oscillations by using satellite gravimetry, altimetry and thermal data in Caspian Sea

    Science.gov (United States)

    Moradi, A.; de Viron, O.; Metivier, L.

    2012-12-01

    As Caspian Sea does not communicate with the world oceans, its dynamics are very different from the global water. Although -as for the world ocean- its level presents regular annual oscillations, estimations from last century and new more precise measurements shows large interannual fluctuations. Changes in the Caspian Sea water volume are investigated using space altimetry, whereas the GRACE satellite gravimetry mission allows monitoring the change of the surface mass distribution. Under the hypothesis that the change in water mass is the only cause of gravity change, it is possible to convert the mass distribution change into volume change, using a steric equation for the sea water. Combinations of multi-mission gridded altimetry data from AVISO with mono mission time series were used in order to analyze the local fluctuations of the lake, revealing a significant tilt between north and south. Large differences in the surface mass distribution rate of change in the basin and in the lake are evidenced in the GRACE data, as well as small differences in phase, which are due to delayed snow melting. Ignoring the short-term changes in water level due to winds, the main reason to cause periodic spatial water level disuniformity is spatial disuniformity in water density. Steric effect was calculated by interfering 2 factors of temperature and salinity. Steric anomaly maps show that it is able to change water level up to 17 cm. As the northern part of the lake has the least salinity in summers the largest effect would be expected to occur in the northern part, but the opposite is observed, probably due to the fact that this part is the shallowest. For the steric anomaly the lake presents spatially variations of 3 cm in winter but 7 cm in the summers. Generally, the largest steric induced fluctuations are observed in the middle of the lake, mostly in the north and east parts of the lake center. We used altimetry and space gravity data jointly, in order to build an improved

  14. Paleohydrology of the southern Great Basin, with special reference to water table fluctuations beneath the Nevada Test Site during the late(?) Pleistocene

    Science.gov (United States)

    Winograd, Isaac Judah; Doty, Gene C.

    1980-01-01

    Knowledge of the magnitude of water-table rise during Pleistocene pluvial climates, and of the resultant shortening of groundwater flow path and reduction in unsaturated zone thickness, is mandatory for a technical evaluation of the Nevada Test Site (NTS) or other arid zone sites as repositories for high-level or transuranic radioactive wastes. The distribution of calcitic veins filling fractures in alluvium, and of tufa deposits between the Ash Meadows spring discharge area and the Nevada Test Site indicates that discharge from the regional Paleozoic carbonate aquifer during the Late( ) Pleistocene pluvial periods may have occurred at an altitude about 50 meters higher than at present and 14 kilometers northeast of Ash Meadows. Use of the underflow equation (relating discharge to transmissivity, aquifer width, and hydraulic gradient), and various assumptions regarding pluvial recharge, transmissivity, and altitude of groundwater base level, suggest possible rises in potentiometric level in the carbonate aquifer of about -90 meters beneath central Frenchman Flat. During Wisconsin time the rise probably did not exceed 30 meters. Water-level rises beneath Frenchman Flat during future pluvials are unlikely to exceed 30 meters and might even be 10 meters lower than modern levels. Neither the cited rise in potentiometric level in the regional carbonate aquifer, nor the shortened flow path during the Late( ) Pleistocene preclude utilization of the NTS as a repository for high-level or transuranic-element radioactive wastes provided other requisite conditions are met as this site. Deep water tables, attendant thick (up to several hundred meter) unsaturated zones, and long groundwater flow paths characterized the region during the Wisconsin Stage and probably throughout the Pleistocene Epoch and are likely to so characterize it during future glacial periods. (USGS)

  15. BWR [boiling water reactor] core criticality versus water level during an ATWS [anticipated transient without scram] event

    International Nuclear Information System (INIS)

    The BWR [boiling water reactor] emergency procedures guidelines recommend management of core water level to reduce the power generated during an anticipated transient without scram (ATWS) event. BWR power level variation has traditionally been calculated in the system codes using a 1-D [one-dimensional] 2-group neutron kinetics model to determine criticality. This methodology used also for calculating criticality of the partially covered BWR cores has, however, never been validated against data. In this paper, the power level versus water level issues in an ATWS severe accident are introduced and the accuracy of the traditional methodology is investigated by comparing with measured data. It is found that the 1-D 2-group treatment is not adequate for accurate predictions of criticality and therefore the system power level for the water level variations that may be encountered in a prototypical ATWS severe accident. It is believed that the current predictions for power level may be too high

  16. Analysis and Depiction of Accessibility Levels of Water Supply Schemes in Rural Akwa Ibom State, Nigeria

    OpenAIRE

    Uwem Ituen; Jacob Atser; Samuel N Edem

    2016-01-01

    This study analyzed and depicted accessibility levels of water schemes in rural areas of Akwa Ibom State, Nigeria. Data on rural water schemes, population data as well as a community map of the study area were utilized. GIS technique was employed in creating a database of water schemes and the spatial distribution of the water schemes displayed on the map of the study area. Based on the criteria stipulated in the National Water Supply and Sanitation Policy for Nigeria, percentage rural water ...

  17. Challenge to high-activity-level water treatment by adsorbents

    International Nuclear Information System (INIS)

    There are over 280,000 tonnes of contaminated water in the damaged Fukushima Daiichi Nuclear Plant site in various tanks and barges and a large amount of contaminated water is now producing at the rate of several tonnes/day owing to inevitable cooling of the reactor cores. SARRY (Simplified Active Water Retrieve and Recovery System) and ALPS (Advanced Liquid Processing System) are installed to remove Cs and multi-elements respectively utilizing ion exchangers (zeolite, crystalline silicon titanate, and metal ferrocyanides) from contaminated water. The author continues efforts to find effective and selective adsorbents for Cs and Sr by measuring partition data, adsorption isotherms and adsorption rate referring with chemical structure elucidated from X-ray diffraction and SEM techniques. The obtained data are presented. (S. Ohno)

  18. Investigation of natural radioactivity level of the waters in Guangdong province

    International Nuclear Information System (INIS)

    This paper reports the investigation results of natural radioactivity level in river, lake, reservoir, spring, tap water and offshore water in Guangdong Province and Hainan Province. There were totally 220 samples collected from 144 measuring points. The results show that the radioactivity level of varied water bodies of the province was within normal natural background

  19. Water-level changes and directions of ground-water flow in the shallow aquifer, Fallon area, Churchill County, Nevada

    Science.gov (United States)

    Seiler, R.L.; Allander, K.K.

    1993-01-01

    The Truckee-Carson-Pyramid Lake Water Rights Settlement Act of 1990 directed the U.S. Fish and Wildlife Service to acquire water rights for wetland areas in the Carson Desert, Nevada. The public is concerned that htis acquisition of water rights and delivery of the water directly to wildlife areas would result in less recharge to the shallow ground water in the Fallon area and cause domestic wells to go dry. In January 1992, the U.S. Geological Survey, in cooperation with U.S. Fish and Wildlife Service, began a study of the shallow ground-water system in the Fallon area in Churchill County, Nevada. A network of 126 wells in the study area was monitored. Between January and November 1992, water levels in most wells declined, usually less than 2 feet. The maximum measured decline over this period was 2.68 feet in a well near Stillwater Marsh. Between April and July, however, water levels rose in irrigated areas, typically 1 to 2 feet. Newlands Project water deliveries to the study area began soon after the turn of the century. Since then, water levels have risen more than 15 feet across much of the study area. Water lost from unlined irrigtiaon canals caused the stage in Big Soda Lake to rise nearly 60 feet; ground-water levels near the lake have risen 30 to 40 feet. The depth to water in most irrigated areas is now less than 10 feet. The altitude of the water table ranges from 4.025 feet above sea level 11 miles west of Fallon to 3,865 feet in the Stillwater Marsh area. Ground water flows eastward and divides; some flow goes to the northeast toward the Carson Sink and Stillwater areas, and some goes southeastward to Carson Lake.

  20. A semi-classical approach of the relationship between simple cells' size and their living temperature limits based on number fluctuations of water coherence domains

    Science.gov (United States)

    Preoteasa, E. A.; Negoita, C.

    2011-12-01

    Starting from the concepts of the quantum electrodynamics (QED) theory of coherence domains (CD) in water we propose a model aimed to evaluate the relationship between the size and the living temperature limits for simple, small cells. Cells are described as spherical potential wells with impenetrable walls, with CDs moving inside. The radius of the spherical potential well was estimated for physiological temperatures and the results match to bacteria and yeasts cells' size. As a CD in the spherical cell exerts a force upon the membrane, a 'gas' formed by CDs bears a pressure on the walls. A classical statistical stability condition relates this pressure to cell volume and to the relative fluctuations of the CD number, allowing the evaluation of an upper temperature limit as a function of cellular volume. Assuming further that the CDs in the living cell form together a coherent state, the number-phase incertitude relationship (Heisenberg limit) applies. The maximum coherence between CDs is found in the ground state, a picture consistent also to Fröhlich's postulate. For a given phase dispersion, a lower temperature limit as a function of the cell volume is found. Although we neglected the rod-like shape of certain bacteria and the presence of nucleus in yeasts, the biological data of volume and optimal living temperature intervals fit well to our model's predictions. Moreover the larger the cell volume, the higher are the number of CDs and the coherence of their system. In addition we suggest a new classification criterion for small cells based on model's parameters, which show discontinuities between Gram negative and positive microorganisms as well as between prokaryotes and the smallest eukaryotes.

  1. Water Hardness Level and ItAND#8217;s Health Effects

    Directory of Open Access Journals (Sweden)

    Necmettin Kocak

    2011-04-01

    Full Text Available Water hardness is a term used to define the number of ions contained in the water, especially quantity sulphate, carbonate salts of calcium and magnesium. This characteristis of water is a important quality in it’s use as drinking water, industrial water and service water. The temporary hardness level of water cames from bicarbonate salts of calcium and magnesium whereas chloride, sulphate, nitrate, phosphate, silicate salts of calcium and magnesium. In order to indicate the hardness level of water samples French Hardness Level is used in our country. There is a larger amounth of calcium and magnesium salts in hard water samples. These minerals have very important functions in the human body. In this study, the importance of hard water in terms of human health has been assessed under light of current information. The studies about the preventive role of hard water in cardiovascular diseases, cerebrovascular diseases, stroke and many types of cancer areviewed. These studies Express that higher levels of calcium and magnesium hard water provide a higher reduction in these disease. Water, which must be consumed as 2 liters per dayis very important for human life. Hard water contains a lot of the minerals that must be taker daily, especially calcium and magnesium. It’s advised that water for consumption to have medium hardness. The hardness level of water is an aesthetic quality. Thus, in populations having a taste for soft water, the effort of individuals to softer the network water provided by municipalities using different equipments, in addition to their preference of soft water in plastic or glass bottles for consumption could imply lack of benefit of hard water for population health and also bring out some risks in terms of water hygiene. [TAF Prev Med Bull 2011; 10(2.000: 187-192

  2. Barometric response functions from borehole water level records and quantification of aquifer vulnerability

    Science.gov (United States)

    Odling, N. E.; Serrano, R. P.; Hussein, M.; Guadagnini, A.; Riva, M.

    2013-12-01

    In confined and semi-confined aquifers, borehole water levels respond to fluctuations in barometric pressure and this response can be used to estimate the properties of aquifer confining layers. We use this response as indicator of groundwater vulnerability for the semi-confined Chalk aquifer in East Yorkshire, UK. Time series data of borehole water levels are corrected for Earth tides and recharge, and barometric response functions (BRFs) estimated using cross-spectral deconvolution-averaging techniques. The resulting BRFs are fitted using a theoretical model of the BRF gain and phase for a semi-confined aquifer (Rojstaczer, 1988) to obtain confining layer properties. For all of the boreholes, non-zero hydraulic diffusivities for the confining layer were found indicating that the aquifer is semi-confined. A ';characteristic time scale' based on the hydraulic and pneumatic diffusivities of the confining layer is introduced as a measure of the degree of aquifer confinement and therefore groundwater vulnerability. The analytical model assumes that the confining layer and aquifer are homogeneous. However, in nature, confining layers are heterogeneous and groundwater vulnerability dominated by the presence of high diffusivity, high flow pathways through the confining layer to the aquifer. A transient numerical model (MODFLOW) was constructed to test the impact of such heterogeneities on the BRF. In the model, an observed barometric pressure time series is used as a boundary condition applied to the upper surface of the top unit of the model (representing the confining layer) and BRFs determined from the time series of model heads in the bottom unit (representing the aquifer). The results from a numerical model with a homogeneous confining layer were found to accurately reproduce the BRFs from a modified version of the analytical model. The introduction of a localized, high diffusive block in the confining layer was found to modify the BRF, reducing the gain amplitude

  3. A method to determine true air temperature fluctuations in clouds with liquid water fraction and estimate water droplet effect on the calculations of the spectral structure of turbulent heat fluxes in cumulus clouds based on aircraft data

    Science.gov (United States)

    Strunin, Alexander M.; Zhivoglotov, Dmitriy N.

    2014-03-01

    Liquid water droplets could distort aircraft temperature measurements in clouds, leading to errors in calculated heat fluxes and incorrect flux distribution pattern. The estimation of cloud droplet effect on the readings of the high-frequency aircraft thermometer employed at the Central Aerological Observatory (CAO) was based on an experimental study of the sensor in a wind tunnel, using an air flow containing liquid water droplets. Simultaneously, calculations of the distribution of speed and temperature in a flow through the sensitive element of the sensor were fulfilled. This permitted estimating the coefficient of water content effect on temperature readings. Another way of estimating cloud droplet effect was based on the analysis of data obtained during aircraft observations of cumulus clouds in a tropical zone (Cuba Island). As a result, a method of correcting air temperature and recovering true air temperature fluctuations inside clouds was developed. This method has provided consistent patterns of heat flux distribution in a cumulus area. Analysis of the results of aircraft observations of cumulus clouds with temperature correction fulfilled has permitted investigation of the spectral structure of the fields of air temperature and heat fluxes to be performed in cumulus zones based on wavelet transformation. It is shown that mesoscale eddies (over 500 m in length) were the main factor of heat exchange between a cloud and the ambient space. The role of turbulence only consisted in mixing inside the cloud.

  4. Investigation of pond water levels during the 1972 waterfowl brooding season

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Water level management in the ponds of Malheur National Wildlife Refuge is important in providing food and habitat for migrating waterfowl. Water flow measurements...

  5. Stochastic modeling of Lake Van water level time series with jumps and multiple trends

    Science.gov (United States)

    Aksoy, H.; Unal, N. E.; Eris, E.; Yuce, M. I.

    2013-06-01

    In the 1990s, water level in the closed-basin Lake Van located in the Eastern Anatolia, Turkey, has risen up about 2 m. Analysis of the hydrometeorological data shows that change in the water level is related to the water budget of the lake. In this study, stochastic models are proposed for simulating monthly water level data. Two models considering mono- and multiple-trend time series are developed. The models are derived after removal of trend and periodicity in the dataset. Trend observed in the lake water level time series is fitted by mono- and multiple-trend lines. In the so-called mono-trend model, the time series is treated as a whole under the hypothesis that the lake water level has an increasing trend. In the second model (so-called multiple-trend), the time series is divided into a number of segments to each a linear trend can be fitted separately. Application on the lake water level data shows that four segments, each fitted with a trend line, are meaningful. Both the mono- and multiple-trend models are used for simulation of synthetic lake water level time series under the hypothesis that the observed mono- and multiple-trend structure of the lake water level persist during the simulation period. The multiple-trend model is found better for planning the future infrastructural projects in surrounding areas of the lake as it generates higher maxima for the simulated lake water level.

  6. Stochastic modeling of Lake Van water level time series with jumps and multiple trends

    Directory of Open Access Journals (Sweden)

    H. Aksoy

    2013-06-01

    Full Text Available In the 1990s, water level in the closed-basin Lake Van located in the Eastern Anatolia, Turkey, has risen up about 2 m. Analysis of the hydrometeorological data shows that change in the water level is related to the water budget of the lake. In this study, stochastic models are proposed for simulating monthly water level data. Two models considering mono- and multiple-trend time series are developed. The models are derived after removal of trend and periodicity in the dataset. Trend observed in the lake water level time series is fitted by mono- and multiple-trend lines. In the so-called mono-trend model, the time series is treated as a whole under the hypothesis that the lake water level has an increasing trend. In the second model (so-called multiple-trend, the time series is divided into a number of segments to each a linear trend can be fitted separately. Application on the lake water level data shows that four segments, each fitted with a trend line, are meaningful. Both the mono- and multiple-trend models are used for simulation of synthetic lake water level time series under the hypothesis that the observed mono- and multiple-trend structure of the lake water level persist during the simulation period. The multiple-trend model is found better for planning the future infrastructural projects in surrounding areas of the lake as it generates higher maxima for the simulated lake water level.

  7. Applying Water-Level Difference Control to Central Arizona Project

    Science.gov (United States)

    The Central Arizona Project (CAP) has been supplying Colorado River water to Central Arizona for roughly 25 years. The CAP canal is operated remotely with a Supervisory Control and Data Acquisition (SCADA) System. Gate position changes are made either manually or through the use of automatic control...

  8. Raising the level: orangutans use water as a tool.

    Science.gov (United States)

    Mendes, Natacha; Hanus, Daniel; Call, Josep

    2007-10-22

    We investigated the use of water as a tool by presenting five orangutans (Pongo abelii) with an out-of-reach peanut floating inside a vertical transparent tube. All orangutans collected water from a drinker and spat it inside the tube to get access to the peanut. Subjects required an average of three mouthfuls of water to get the peanut. This solution occurred in the first trial and all subjects continued using this successful strategy in subsequent trials. The latency to retrieve the reward drastically decreased after the first trial. Moreover, the latency between mouthfuls also decreased dramatically from the first mouthful in the first trial to any subsequent ones in the same trial or subsequent trials. Additional control conditions suggested that this response was not due to the mere presence of the tube, to the existence of water inside, or frustration at not getting the reward. The sudden acquisition of the behaviour, the timing of the actions and the differences with the control conditions make this behaviour a likely candidate for insightful problem solving. PMID:17609175

  9. Influence of water fluctuations on the limnological characteristics of two floodplain lagoons (Ribeira do Iguape Valley, state of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Rogério Herlon Furtado Freire

    2015-12-01

    Full Text Available Abstract Aim: Current study assessed the influence of hydrometric levels on the limnological characteristics of two river floodplain systems in the Ribeira do Iguape Basin (state of São Paulo, Brazil. Methods: Rainfall data were collected dailyfrom an automatic weather station in Jacupiranga SP Brazil and daily hydrometric level records were obtained from automatic linigraphs installed on the two adjacent rivers. Moreover, pH, electrical conductivity and dissolved oxygen were measured by a multiparametric probe. Water samples were collected to analyze nitrate, ammoniac nitrogen, total nitrogen and phosphorus, total alkalinity and suspended material. The samplings were carried out in April and July, representative months for low and high water periods, respectively. Results and Conclusions: Statistical analysis highlighted the “effect of homogenization”, attributed to the hydrological pulses in several studies carried out in river-floodplain systems. This effect in current study was more underscored at Lagoon 2, which remained connected for a longer period with the adjacent river, when compared to Lagoon 1- River Jacupiranguinha system. Higher dissolved oxygen concentrations at Lagoon 2, in contrast with the Lagoon 1 featuring anoxia during the whole period under analysis, were also attributed to the above-mentioned greater hydrological connectivity. Current study highlights that the water-mediated transferences during the high water period may contribute not only towards the fertilization of marginal lagoons (inputs of nutrients and organic matter but also to significant pollutant loads, according to land use along the watersheds. In the case of Lagoon 1- River Jacupiranguinha system, even though further studies are needed and strongly recommended, it is reasonable to assume that the discharges of mining effluents into the river may result in ecological damage not only to the receiving water body but also to the connected ecosystems.

  10. The economics of leaf-gas exchange in a fluctuating environment and their upscaling to the canopy-level using turbulent transport theories

    Science.gov (United States)

    Katul, G. G.; Palmroth, S.; Manzoni, S.; Oren, R.

    2012-12-01

    Global climate models predict decreases in leaf stomatal conductance (gs) and transpiration due to increases in atmospheric CO2. The consequences of these reductions are increases in soil moisture availability and continental scale run-off at decadal time-scales. Thus, a theory explaining the differential sensitivity of stomata to changing atmospheric CO2 and other environmental conditions such as soil moisture at the ecosystem scale must be identified. Here, these responses are investigated using an optimality theory applied to stomatal conductance. An analytical model for gs is first proposed based on (a) Fickian mass transfer of CO2 and H2O through stomata; (b) a biochemical photosynthesis model that relates intercellular CO2 to net photosynthesis; and (c) a stomatal model based on optimization for maximizing carbon gains when water losses represent a cost. The optimization theory produced three gas exchange responses that are consistent with observations across a wide-range of species: (1) the sensitivity of gs to vapour pressure deficit (D) is similar to that obtained from a previous synthesis of more than 40 species, (2) the theory is consistent with the onset of an apparent 'feed-forward' mechanism in gs, and (3) the emergent non-linear relationship between the ratio of intercellular to atmospheric CO2 (ci/ca) and D agrees with the results available on this response. A simplified version of this leaf-scale approach recovers the linear relationship between stomatal conductance and leaf-photosynthesis employed in numerous climate models that currently use a variant on the 'Ball-Berry' or the 'Leuning' approaches provided the marginal water use efficiency increases linearly with atmospheric CO2. The model is then up-scaled to the canopy-level using novel theories about the structure of turbulence inside vegetation. This up-scaling proved to be effective in resolving the complex (and two-way) interactions between leaves and their immediate micro

  11. Theory and Method for Identifying Well Water Level Anomalies in a Groundwater Overdraft Area

    Institute of Scientific and Technical Information of China (English)

    Zhang Suxin; Zhang Ziguang; Ren Xiaoxia; Wang Xiang

    2007-01-01

    The overexploitation of underground water leads to the continuous drawdown of groundwater levels, change of water quality and dry-up in dynamic water level observation wells. Due to land subsidence, the well pipes uplift and the observation piping systems are damaged. These environmental geology problems can present serious difficulties for the identification of earthquake anomalies by groundwater level observation. Basied on hydrogeological theories and methods, the paper analyzes the relations of the water balance state of aquifers with stressstrain conditions and the water level regime, and then discusses preliminarily the theory and method for identifying well water level anomalies in a groundwater overdraft area. The result shows that we can accurately judge the nature of the anomaly according to the diffusion character of the drawdown funnel in the well area in combination with the aforementioned theory and method and multi-year variation patterns obtained from existing data. The results of the research are helpful for distinguishing the influence of single centralized water pumping from the long-term overdraft of water on the water level, correctly recognizing water level anomalies in the groundwater overdraft area and increasing the level of earthquake analysis and prediction.

  12. Is China's fifth-largest inland lake to dry-up? Incorporated hydrological and satellite-based methods for forecasting Hulun lake water levels

    Science.gov (United States)

    Cai, Zuansi; Jin, Taoyong; Li, Changyou; Ofterdinger, Ulrich; Zhang, Sheng; Ding, Aizhong; Li, Jiancheng

    2016-08-01

    Hulun Lake, China's fifth-largest inland lake, experienced severe declines in water level in the period of 2000-2010. This has prompted concerns whether the lake is drying up gradually. A multi-million US dollar engineering project to construct a water channel to transfer part of the river flow from a nearby river to maintain the water level was completed in August 2010. This study aimed to advance the understanding of the key processes controlling the lake water level variation over the last five decades, as well as investigate the impact of the river transfer engineering project on the water level. A water balance model was developed to investigate the lake water level variations over the last five decades, using hydrological and climatic data as well as satellite-based measurements and results from land surface modelling. The investigation reveals that the severe reduction of river discharge (-364 ± 64 mm/yr, ∼70% of the five-decade average) into the lake was the key factor behind the decline of the lake water level between 2000 and 2010. The decline of river discharge was due to the reduction of total runoff from the lake watershed. This was a result of the reduction of soil moisture due to the decrease of precipitation (-49 ± 45 mm/yr) over this period. The water budget calculation suggests that the groundwater component from the surrounding lake area as well as surface run off from the un-gauged area surrounding the lake contributed ∼ net 210 Mm3/yr (equivalent to ∼ 100 mm/yr) water inflows into the lake. The results also show that the water diversion project did prevent a further water level decline of over 0.5 m by the end of 2012. Overall, the monthly water balance model gave an excellent prediction of the lake water level fluctuation over the last five decades and can be a useful tool to manage lake water resources in the future.

  13. Study on Volume Strain Inversion from Water Level Change of Well-aquifer Systems

    Institute of Scientific and Technical Information of China (English)

    Yan Rui; Gao Fuwang; Chen Yong

    2008-01-01

    Based on linear poroelastic and hydrogcology theory, a mathematical expression describing the relationship between water level change and aquifer volume strain is put forward. Combined with earth tidal theory, we analyze the response characteristics from well-aquifer water level change to earth tide of volume strain and present a method of volume strain inversion from water level change. Comparing the results of inversion with real observed data, we found that there is a good consistency. This suggcsts that the method of volume strain inversion from water level change is proper. It will offer a reference for learning about hydrogeology characteristics, volume strain and searching for precursor anomalies.

  14. Identification and simulation for steam generator water level based on Kalman Filter

    International Nuclear Information System (INIS)

    In order to effectively control the water level of the steam generator (SG), this paper has set about the state-observer theory in modern control and put forward a method to detect the 'false water level' based on Kalman Filter. Kalman Filter is a efficient tool to estimate state-variable by measured value including noise. For heavy measurement noise of steam flow, constructing a 'false water level' observer by Kalman Filter could availably obtain state variable of 'false water level'. The simulation computing for the dynamics characteristic of nuclear SG water level process under several typically running power was implemented by employing the simulation model. The result shows that the simulation model accurately identifies the 'false water level' produced in the reverse thermal-dynamic effects of nuclear SG water level process. The simulation model can realize the precise analysis of dynamics characteristic for the nuclear SG water level process. It can provide a kind of new ideas for the 'false water level' detecting of SG. (authors)

  15. Hydrology and water quality of Shell Lake, Washburn County, Wisconsin, with special emphasis on the effects of diversion and changes in water level on the water quality of a shallow terminal lake

    Science.gov (United States)

    Juckem, Paul F.; Robertson, Dale M.

    2013-01-01

    Shell Lake is a relatively shallow terminal lake (tributaries but no outlets) in northwestern Wisconsin that has experienced approximately 10 feet (ft) of water-level fluctuation over more than 70 years of record and extensive flooding of nearshore areas starting in the early 2000s. The City of Shell Lake (City) received a permit from the Wisconsin Department of Natural Resources in 2002 to divert water from the lake to a nearby river in order to lower water levels and reduce flooding. Previous studies suggested that water-level fluctuations were driven by long-term cycles in precipitation, evaporation, and runoff, although questions about the lake’s connection with the groundwater system remained. The permit required that the City evaluate assumptions about lake/groundwater interactions made in previous studies and evaluate the effects of the water diversion on water levels in Shell Lake and other nearby lakes. Therefore, a cooperative study between the City and U.S. Geological Survey (USGS) was initiated to improve the understanding of the hydrogeology of the area and evaluate potential effects of the diversion on water levels in Shell Lake, the surrounding groundwater system, and nearby lakes. Concerns over deteriorating water quality in the lake, possibly associated with changes in water level, prompted an additional cooperative project between the City and the USGS to evaluate efeffects of changes in nutrient loading associated with changes in water levels on the water quality of Shell Lake. Numerical models were used to evaluate how the hydrology and water quality responded to diversion of water from the lake and historical changes in the watershed. The groundwater-flow model MODFLOW was used to simulate groundwater movement in the area around Shell Lake, including groundwater/surface-water interactions. Simulated results from the MODFLOW model indicate that groundwater flows generally northward in the area around Shell Lake, with flow locally converging

  16. Dual-Level Material and Psychological Assessment of Urban Water Security in a Water-Stressed Coastal City

    Directory of Open Access Journals (Sweden)

    Yajing Huang

    2015-04-01

    Full Text Available The acceleration of urbanization and industrialization has been gradually aggravating water security issues, such as water shortages, water pollution, and flooding or drought disasters and so on. Water security issues have become a great challenge to urban sustainable development. In this context, we proposed a dual-level material and psychological assessment method to assess urban water security. Psychological security coefficients were introduced in this method to combine material security and residents’ security feelings. A typical water-stressed coastal city in China (Dalian was chosen as a case study. The water security status of Dalian from 2010 to 2012 was analysed dynamically. The results indicated that the Dalian water security statuses from 2010 to 2012 were basically secure, but solutions to improve water security status and solve water resource problems are still required. This dual-level material and psychological assessment for urban water security has improved conventional material assessment through the introduction of psychological security coefficients, which can benefit decision-making for urban water planning, management and protection.

  17. Characterizing price index behavior through fluctuation dynamics

    CERN Document Server

    Panigrahi, Prasanta K; Banerjee, Arjun; Bahadur, Jainendra; Manimaran, P

    2012-01-01

    We study the nature of fluctuations in variety of price indices involving companies listed on the New York Stock Exchange. The fluctuations at multiple scales are extracted through the use of wavelets belonging to Daubechies basis. The fact that these basis sets satisfy vanishing moments conditions makes them ideal to extract local polynomial trends, through the low pass or `average coefficients'. Subtracting the trends from the original time series yields the fluctuations, at different scales, depending on the level of low-pass coefficients used for finding the `average behavior'. The fluctuations are then studied using wavelet based multifractal detrended fluctuation analysis to analyze their self-similar and non-statistical properties. Due to the multifractality of such time series, they deviate from Gaussian behavior in different frequency regimes. Their departure from random matrix theory predictions in such regimes is also analyzed. These deviations and non-statistical properties of the fluctuations can...

  18. A data set of worldwide glacier fluctuations

    NARCIS (Netherlands)

    Leclercq, P.W.; Oerlemans, J.; Basagic, H.J.; Bushueva, I.; Cook, A.J.; Le Bris, R.

    2014-01-01

    Glacier fluctuations contribute to variations in sea level and historical glacier length fluctuations are natural indicators of past climate change. To study these subjects, longterm information of glacier change is needed. In this paper we present a data set of global long-term glacier length fluct

  19. Dissipative Dynamics of Quantum Fluctuations

    CERN Document Server

    Benatti, F; Floreanini, R

    2015-01-01

    One way to look for complex behaviours in many-body quantum systems is to let the number $N$ of degrees of freedom become large and focus upon collective observables. Mean-field quantities scaling as $1/N$ tend to commute, whence complexity at the quantum level can only be inherited from complexity at the classical level. Instead, fluctuations of microscopic observables scale as $1/\\sqrt{N}$ and exhibit collective Bosonic features, typical of a mesoscopic regime half-way between the quantum one at the microscopic level and the classical one at the level of macroscopic averages. Here, we consider the mesoscopic behaviour emerging from an infinite quantum spin chain undergoing a microscopic dissipative, irreversible dynamics and from global states without long-range correlations and invariant under lattice translations and dynamics. We show that, from the fluctuations of one site spin observables whose linear span is mapped into itself by the dynamics, there emerge bosonic operators obeying a mesoscopic dissipa...

  20. Preliminary Assessment of Water Levels in Bedrock Wells in New Hampshire, 1984 to 2007

    Science.gov (United States)

    Ayotte, Joseph D.; Kernen, Brandon M.; Wunsch, David R.; Argue, Denise M.; Bennett, Derek S.; Mack, Thomas J.

    2010-01-01

    Analysis of nearly 60,000 reported values of static water level (SWL, as depth below land surface) in bedrock wells in New Hampshire, aggregated on a yearly basis, showed an apparent deepening of SWL of about 13 ft (4 m) over the period 1984–2007. Water-level data were one-time measurements at each well and were analyzed, in part, to determine if they were suitable for analysis of trends in groundwater levels across the state. Other well characteristics, however, also have been changing over time, such as total well depth, casing length, the length of casing in bedrock, and to some extent, well yield. Analyses indicated that many of the well construction variables are significantly correlated; the apparent declines in water levels may have been caused by some of these factors. Information on changes in water use for the period was not available, although water use may be an important factor affecting water levels.

  1. Design and Implementation of a Water Level Controller using Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Namrata Dey

    2013-06-01

    Full Text Available This paper analyzes the effectiveness of water level control using fuzzy logic. The water level in the tank is sensed using transistor switching principle. The level sensed is fed to the PIC16 microcontroller. The user provides the set point to the microcontroller through serial communication using the COM development port software, Terminal. It computes the error as the difference between the set point and the process variable. The fuzzy logic programmed in the microcontroller is applied which controls the water level in the tank using the drain and the feed pumps. Once the set point has been reached, the message along with the present level is sent back through serial communication to the user interface on a PC. Thus, the water level in the tank is controlled according to the set point given by the user. The implementation of a fuzzy level controller has many applications such as boiler drum level control, reverse osmosis plant, demineralisation plant etc.

  2. Towards risk-based drought management in the Netherlands: making water supply levels transparent to water users

    Science.gov (United States)

    Maat Judith, Ter; Marjolein, Mens; Vuren Saskia, Van; der Vat Marnix, Van

    2016-04-01

    To prepare the Dutch Delta for future droughts and water scarcity, a nation-wide 4-year project, called Delta Programme, assessed the impact of climate change and socio-economic development, and explored strategies to deal with these impacts. The Programme initiated a joint approach to water supply management with stakeholders and developed a national adaptation plan that is able to adapt to future uncertain conditions. The adaptation plan consists of a set of preferred policy pathways - sequences of possible actions and measures through time - to achieve targets while responding in a flexible manner to uncertain developments over time, allowing room to respond to new opportunities and insights. With regard to fresh water allocation, the Delta Programme stated that supplying water of sufficient quality is a shared responsibility that requires cohesive efforts among users in the main and regional water system. The national and local authorities and water users involved agreed that the water availability and, where relevant, the water quality should be as transparent and predictable as possible under normal, dry and extremely dry conditions. They therefore introduced the concept of "water supply service levels", which should describe water availability and quality that can be delivered with a certain return period, for all regions and all relevant water users in the Netherlands. The service levels form an addition to the present policy and should be decided on by 2021. At present water allocation during periods of (expected) water shortage occurs according to a prearranged ranking system (a water hierarchy scheme based on a list of priorities), if water availability drops below a critical low level. The aim is to have supply levels available that are based on the probability of occurrence and economic impact of water shortage, and that are transparent for all water users in the regional water systems and the main water system. As part of the European project

  3. Statistical analysis of lake levels and field study of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015: Chapter A of Water levels and groundwater and surface-water exchanges in lakes of the northeast Twin Cities Metropolitan Area, Minnesota, 2002 through 2015

    Science.gov (United States)

    Jones, Perry M.; Trost, Jared J.; Diekoff, Aliesha L.; Rosenberry, Donald O.; White, Eric A.; Erickson, Melinda L.; Morel, Daniel L.; Heck, Jessica M.

    2016-10-19

    Water levels declined from 2003 to 2011 in many lakes in Ramsey and Washington Counties in the northeast Twin Cities Metropolitan Area, Minnesota; however, water levels in other northeast Twin Cities Metropolitan Area lakes increased during the same period. Groundwater and surface-water exchanges can be important in determining lake levels where these exchanges are an important component of the water budget of a lake. An understanding of groundwater and surface-water exchanges in the northeast Twin Cities Metropolitan Area has been limited by the lack of hydrologic data. The U.S. Geological Survey, in cooperation with the Metropolitan Council and Minnesota Department of Health, completed a field and statistical study assessing lake-water levels and regional and local groundwater and surface-water exchanges near northeast Twin Cities Metropolitan Area lakes. This report documents the analysis of collected hydrologic, water-quality, and geophysical data; and existing hydrologic and geologic data to (1) assess the effect of physical setting and climate on lake-level fluctuations of selected lakes, (2) estimate potential percentages of surface-water contributions to well water across the northeast Twin Cities Metropolitan Area, (3) estimate general ages for waters extracted from the wells, and (4) assess groundwater inflow to lakes and lake-water outflow to aquifers downgradient from White Bear Lake. Statistical analyses of lake levels during short-term (2002–10) and long-term (1925–2014) periods were completed to help understand lake-level changes across the northeast Twin Cities Metropolitan Area. Comparison of 2002–10 lake levels to several landscape and geologic characteristics explained variability in lake-level changes for 96 northeast Twin Cities Metropolitan Area lakes. Application of several statistical methods determined that (1) closed-basin lakes (without an active outlet) had larger lake-level declines than flow-through lakes with an outlet; (2

  4. Water-level records for the Big Sioux Aquifer, Minnehaha County, South Dakota

    Science.gov (United States)

    Bradford, Wendell L.

    1981-01-01

    This report contains a tabulation of water levels in wells tapping the Big Sioux aquifer in Minnehaha County, S. Dak. Included is a compilation of all water levels in 43 wells measured by the U.S. Geological Survey and State agencies during the period 1957-80. The data are presented in tabular and graphic form. (USGS)

  5. DOWNSTREAM-WATER-LEVEL CONTROL TEST RESULTS ON THE WM LATERAL CANAL

    Science.gov (United States)

    On steep canals, distant downstream water-level control can be challenging. SacMan (Software for Automated Canal Management) was developed, in part, to test various distant downstream water level controllers. It was implemented on the WM canal of the Maricopa Stanfield Irrigation and Drainage Distri...

  6. Persistent water level changes in a well near Parkfield, California, due to local and distant earthquakes

    Science.gov (United States)

    Roeloffs, Evelyn A.

    1998-01-01

    Coseismic water level rises in the 30-m deep Bourdieu Valley (BV) well near Parkfield, California, have occurred in response to three local and five distant earthquakes. Coseismic changes in static strain cannot explain these water level rises because (1) the well is insensitive to strain at tidal periods; (2) for the distant earthquakes, the expected coseismic static strain is extremely small; and (3) the water level response is of the incorrect sign for the local earthquakes. These water level changes must therefore be caused by seismic waves, but unlike seismic water level oscillations, they are monotonic, persist for days or weeks, and seem to be caused by waves with periods of several seconds rather than long-period surface waves. Other investigators have reported a similar phenomenon in Japan. Certain wells consistently exhibit this type of coseismic water level change, which is always in the same direction, regardless of the earthquake's azimuth or focal mechanism, and approximately proportional to the inverse square of hypocentral distance. To date, the coseismic water level rises in the B V well have never exceeded the seasonal water level maximum, although their sizes are relatively well correlated with earthquake magnitude and distance. The frequency independence of the well's response to barometric pressure in the frequency band 0.1 to 0.7 cpd implies that the aquifer is fairly well confined. High aquifer compressibility, probably due to a gas phase in the pore space, is the most likely reason why the well does not respond to Earth tides. The phase and amplitude relationships between the seasonal water level and precipitation cycles constrain the horizontal hydraulic diffusivity to within a factor of 4.5, bounding hypothetical earthquake-induced changes in aquifer hydraulic properties. Moreover, changes of hydraulic conductivity and/or diffusivity throughout the aquifer would not be expected to change the water level in the same direction at every time

  7. Natural circulation steam generator model for optimal steam generator water level control

    International Nuclear Information System (INIS)

    Several authors have cited the control of steam generator water level as an important problem in the operation of pressurized water reactor plants. In this paper problems associated with steam generator water level control are identified, and advantages of modern estimation and control theory in dealing with these problems are discussed. A new state variable steam generator model and preliminary verification results using data from the loss of fluid test (LOFT) plant are also presented

  8. Reactor vessel water level estimation during severe accidents using cascaded fuzzy neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Yeong; Yoo, Kwae Hwan; Choi, Geon Pil; Back, Ju Hyun; Na, Man Gyun [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of)

    2016-06-15

    Global concern and interest in the safety of nuclear power plants have increased considerably since the Fukushima accident. In the event of a severe accident, the reactor vessel water level cannot be measured. The reactor vessel water level has a direct impact on confirming the safety of reactor core cooling. However, in the event of a severe accident, it may be possible to estimate the reactor vessel water level by employing other information. The cascaded fuzzy neural network (CFNN) model can be used to estimate the reactor vessel water level through the process of repeatedly adding fuzzy neural networks. The developed CFNN model was found to be sufficiently accurate for estimating the reactor vessel water level when the sensor performance had deteriorated. Therefore, the developed CFNN model can help provide effective information to operators in the event of a severe accident.

  9. Anomalies in Water Level Records in Yunnan Caused by the Great Indonesian Earthquakes and Their Significance

    Institute of Scientific and Technical Information of China (English)

    Fu Hong; Wu Chengdong; Liu Qiang; Wang Shiqin; Chen Yan

    2008-01-01

    Two great earthquakes occurred in the sea northwest of Sumatra,Indonesia,on December 26,2004 and March 29,2005.The observation of water levels in Yunnan yielded abundant information about the two earthquakes.This paper presents the water level response to the two earthquakes in Yunnan and makes a preliminary analysis.It is observed that the large earthquake-induced abnormal water level change could be better recorded by analog recording than by digital recording.The large earthquake-caused water level rise or decline may be attributed to the effect of seismic waves that change the stress in tectonic units,and is correlated with the geological structure where the well is located.The water level response mode in a well is totally the same for earthquakes occurring on the same fault and with the same fracture mode.The only difference is that the response amplitude increases with the growth of the earthquake magnitude.

  10. Seven years of external control of fluoride levels in the public water supply in Bauru, Sao Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Marilia Afonso Rabelo BUZALAF

    2013-01-01

    Full Text Available Fluoridation of the public water supplies is recognized as among the top ten public health achievements of the twentieth century. However, the positive aspects of this measure depend on the maintenance of fluoride concentrations within adequate levels. Objective To report the results of seven years of external control of the fluoride (F concentrations in the public water supply in Bauru, SP, Brazil in an attempt to verify, on the basis of risk/benefit balance, whether the levels are appropriate. Material and Methods From March 2004 to February 2011, 60 samples were collected every month from the 19 supply sectors of the city, totaling 4,641 samples. F concentrations in water samples were determined in duplicate, using an ion-specific electrode (Orion 9609 coupled to a potentiometer after buffering with TISAB II. After the analysis, the samples were classified according to the best risk-benefit adjustment. Results Means (±standard deviation of F concentrations ranged between 0.73±0.06 and 0.81±0.10 mg/L for the different sectors during the seven years. The individual values ranged between 0.03 and 2.63 mg/L. The percentages of the samples considered “low risk” for dental fluorosis development and of “maximum benefit” for dental caries prevention (0.55-0.84 mg F/L in the first, second, third, fourth, fifth, sixth, and seventh years of the study were 82.0, 58.5, 37.4, 61.0, 89.9, 77.3, and 72.4%, respectively, and 69.0% for the entire period. Conclusions Fluctuations of F levels were found in the public water supply in Bauru during the seven years of evaluation. These results suggest that external monitoring of water fluoridation by an independent assessor should be implemented in cities where there is adjusted fluoridation. This measure should be continued in order to verify that fluoride levels are suitable and, if not, to provide support for the appropriate adjustments.

  11. Effects of water level on three wetlands soil seed banks on the Tibetan Plateau.

    Directory of Open Access Journals (Sweden)

    Miaojun Ma

    Full Text Available BACKGROUND: Although the effect of water level on germination in soil seed banks has been documented in many ecosystems, the mechanism is not fully understood, and to date no empirical studies on this subject exist. Further, no work has been done on the effect of water level on seed banks of drying and saline-alkaline wetlands in alpine areas on the Tibetan Plateau. METHODOLOGY: We examined the effects of water level (0 cm, 5 cm and 10 cm on seed germination and seedling establishment from soil seed banks at 0-5 cm and 5-10 cm depths in typical, drying, and saline-alkaline wetlands. We also explore the potential role of soil seed bank in restoration of drying and saline-alkaline wetlands. PRINCIPAL FINDINGS: Species richness decreased with increase in water level, but there almost no change in seed density. A huge difference exists in species composition of the seed bank among different water levels in all three wetlands, especially between 0 cm and 5 cm and 0 cm and 10 cm. Similarity of species composition between seed bank and plant community was higher in 0 cm water level in drying wetland than in the other two wetlands. The similarity was much higher in 0 cm water level than in 5 cm and 10 cm water levels in all three wetlands. Species composition of the alpine wetland plant community changed significantly after drying and salinization, however, species composition of the seed bank was unchanged regardless of the environment change. CONCLUSIONS/SIGNIFICANCE: Water level greatly affects seed bank recruitment and plant community establishment. Further, different water levels in restored habitats are likely to determine its species composition of the plant community. The seed bank is important in restoration of degraded wetlands. Successful restoration of drying and salinization wetlands could depend on the seed bank.

  12. Understanding consumption and residential uses of water at the household level in Quito, Ecuador

    OpenAIRE

    Oscar Zapata

    2011-01-01

    Climate change, water scarcity, costly infrastructure projects, and inadequate pricing schemes and inefficient subsidies, are just a few reasons of concern for the current and future provision of potable water in many cities of the world. The understanding of consumer behavior may inform policy makers about cost-effective measures to achieve sustainable levels of water consumption. From an economic perspective, water pricing policies might be very effective to modify consumption patterns and ...

  13. Study of emergency-action levels for light water reactors

    International Nuclear Information System (INIS)

    An emergency action level (EAL) is an observation or judgment that forms the basis for declaring an emergency status at a nuclear generating facility. There are four graded emergency category classifications which indicate an increasing potential for offsite radiological impact. Each emergency category is normally associated with an implementation procedure that outlines the preplanned actions that the emergency director will undertake. Thus a transient which causes a system or parameter to reach an EAL will also cause a transition of the normal station organization to an emergency organization. This transition will include an augmentation of the basic shift staff in order to support the corrective and mitigative actions of the nuclear reactor operators. In this regard, the major purpose of EALs is to provide an early indication of potential problems. Ideally, the ensuing response of the emergency organization will prevent a propagation of errors or failures that could result in serious consequences

  14. The Water Footprint as an indicator of environmental sustainability in water use at the river basin level.

    Science.gov (United States)

    Pellicer-Martínez, Francisco; Martínez-Paz, José Miguel

    2016-11-15

    One of the main challenges in water management is to determine how the current water use can condition its availability to future generations and hence its sustainability. This study proposes the use of the Water Footprint (WF) indicator to assess the environmental sustainability in water resources management at the river basin level. The current study presents the methodology developed and applies it to a case study. The WF is a relatively new indicator that measures the total volume of freshwater that is used as a production factor. Its application is ever growing in the evaluation of water use in production processes. The calculation of the WF involves water resources (blue), precipitation stored in the soil (green) and pollution (grey). It provides a comprehensive assessment of the environmental sustainability of water use in a river basin. The methodology is based upon the simulation of the anthropised water cycle, which is conducted by combining a hydrological model and a decision support system. The methodology allows the assessment of the environmental sustainability of water management at different levels, and/or ex-ante analysis of how the decisions made in water planning process affect sustainability. The sustainability study was carried out in the Segura River Basin (SRB) in South-eastern Spain. The SRB is among the most complex basins in Europe, given its special peculiarities: competition for the use, overexploitation of aquifers, pollution, alternative sources, among others. The results indicate that blue water use is not sustainable due to the generalised overexploitation of aquifers. They also reveal that surface water pollution, which is not sustainable, is mainly caused by phosphate concentrations. The assessment of future scenarios reveals that these problems will worsen if no additional measures are implemented, and therefore the water management in the SRB is environmentally unsustainable in both the short- and medium-term. PMID:27405519

  15. Particle density fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, M.M.; Ahammed, Z.; Angelis, A.L.S.; Antonenko, V.; Arefiev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Bathe, S.; Batiounia, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bucher, D.; Buesching, H.; Carlen, L.; Chattopadhyay, S.; Das, A.C.; Decowski, M.P.; Donni, P.; Dubey, A.K.; Dutta Majumdar, M.R.; Enosawa, K.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishcuk, O.; Geurts, F.J.M.; Glasow, R.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Karadjev, K.; Karpio, K.; Kolb, B.W.; Kosarev, I.; Koutcheryaev, I.; Kugler, A.; Kulinich, P.; Kurata, M.; Lebedev, A.; Loehner, H.; Mahapatra, D.P.; Manko, V.; Martin, M.; Miake, Y.; Mishra, G.C.; Mohanty, B.; Morrison, D.; Mukhopadhayay, D.S.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nishimura, S.; Nomokov, P.; Petracek, V.; Plasil, F.; Purschke, M.L.; Rak, J.; Raniwala, R.; Raniwala, S.; Rao, N.K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Rubio, J.M.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.-R.; Schutz, Y.; Shabratova, G.; Sibiriak, I.; Siemiarczuk, T.; Sinha, B.C.; Slavine, N.; Soederstroem, K.; Sood, G.; Soerensen, S.P.; Stankus, P.; Steinberg, P.; Stenlund, E.; Sumbera, M.; Svensson, T.; Trivedi, M.D.; Tsvetkov, A.; Tykarski, L.; Urbahn, J.; Eijinhoven, N. van; Niewenhuizen, G.J. van; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.; Voeroes, S.; Wyslouch, B.; Young, G.R

    2003-03-10

    Event-by-event fluctuations in the multiplicities of charged particles and photons at SPS energies are discussed. Fluctuations are studied by controlling the centrality of the reaction and rapidity acceptance of the detectors. Results are also presented on the event-by-event study of correlations between the multiplicity of charged particles and photons to search for DCC-like signals.

  16. GRACE-Based Analysis of Total Water Storage Trends and Groundwater Fluctuations in the North-Western Sahara Aquifer System (NWSAS) and Tindouf Aquifer in Northwest Africa

    Science.gov (United States)

    Lezzaik, K. A.; Milewski, A.

    2013-12-01

    Optimal water management practices and strategies, in arid and semi-arid environments, are often hindered by a lack of quantitative and qualitative understanding of hydrological processes. Moreover, progressive overexploitation of groundwater resources to meet agricultural, industrial, and domestic requirements is drawing concern over the sustainability of such exhaustive abstraction levels, especially in environments where groundwater is a major source of water. NASA's GRACE (gravity recovery and climate change experiment) mission, since March 2002, has advanced the understanding of hydrological events, especially groundwater depletion, through integrated measurements and modeling of terrestrial water mass. In this study, GLDAS variables (rainfall rate, evapotranspiration rate, average soil moisture), and TRMM 3B42.V7A precipitation satellite data, were used in combination with 95 GRACE-generated gravitational anomalies maps, to quantify total water storage change (TWSC) and groundwater storage change (GWSC) from January 2003 to December 2010 (excluding June 2003), in the North-Western Sahara Aquifer System (NWSAS) and Tindouf Aquifer System in northwestern Africa. Separately processed and computed GRACE products by JPL (Jet Propulsion Laboratory, NASA), CSR (Center of Space Research, UT Austin), and GFZ (German Research Centre for Geoscience, Potsdam), were used to determine which GRACE dataset(s) best reflect total water storage and ground water changes in northwest Africa. First-order estimates of annual TWSC for NWSAS (JPL: +5.297 BCM; CSR: -5.33 BCM; GFZ: -9.96 BCM) and Tindouf Aquifer System (JPL: +1.217 BCM; CSR: +0.203 BCM; GFZ: +1.019 BCM), were computed using zonal averaging over a span of eight years. Preliminary findings of annual GWSC for NWSAS (JPL: +2.45 BCM; CSR: -2.278 BCM; GFZ: -6.913 BCM) and Tindouf Aquifer System (JPL: +1.108 BCM; CSR: +0.094 BCM; GFZ: +0.910 BCM), were calculating using a water budget approach, parameterized by GLDAS

  17. Analysis of Long-Term Water Level Variation in Dongting Lake, China

    Directory of Open Access Journals (Sweden)

    Qiaoqian Han

    2016-07-01

    Full Text Available The water level of Dongting Lake has changed because of the combined impact of climatic change and anthropogenic activities. A study of the long-term statistical properties of water level variations at Chenglingji station will help with the management of water resources in Dongting Lake. In this case, 54 years of water level data for Dongting Lake were analyzed with the non-parametric Mann–Kendall trend test, Sen’s slope test, and the Pettitt test. The results showed the following: (1 Trends in annual maximum lake water level (WLM, annual mean lake water level (WL, and annual minimum lake water level (WLm increased from 1961 to 2014; however, the three variables showed different trends from 1981 to 2014; (2 The annual change trends in Dongting Lake between 1961–2014 and 1981–2014 were found to be from approximately 0.90 cm/year to −2.27 cm/year, 1.65 cm/year to −0.79 cm/year, and 4.58 cm/year to 2.56 cm/year for WLM, WL, and WLm, respectively; (3 A greater degree of increase in water level during the dry season (November–April was found from 2003 to 2014 than from 1981 to 2002, but a smaller degree of increase, even to the point of decreasing, was found during the wet season (May–October; (4 The measured discharge data and numerical modeling results showed the operation of Three Gorge Reservoir (TGR pushed to influence partly the recent inter-annual variation of water level in Dongting Lake region, especially in the flood and dry seasons. The analysis indicated that the water level of Dongting Lake has changed in the long term with decreasing of range between WLM and WLm, and may decrease the probability of future drought and flood events. These results can provide useful information for the management of Dongting Lake.

  18. Efficient local personal cooling with fluctuating airflows

    NARCIS (Netherlands)

    Bakker, L.G.; Hoes-van Oeffelen, E.C.M.; Hordijk, G.J.; Ham, E.R. van de

    2015-01-01

    Overheating in buildings is an increasingly important issue. Various studies show that local personalized cooling can substantially improve comfort levels while saving energy. Airflows are an efficient approach for local cooling. Fluctuating airflows seem more effective and are potentially perceived

  19. Numerical Simulation of Elimination of Pressure Fluctuation in Francis Turbine Draft Tube Using Water Jet%射水减弱混流式水轮机尾水管内压力脉动的数值模拟

    Institute of Scientific and Technical Information of China (English)

    李章超; 常近时; 辛喆

    2013-01-01

    3-D unsteady turbulent flow simulation with RNG k - e turbulence model of complete flow passage on Francis turbine at partial load condition was performed. The simulation results were compared with the test data. The simulation predicted the pressure fluctuation magnitude and frequency characteristic in the draft tube successfully. A method injecting water from the crown tip to the turbine draft tube to weaken the pressure fluctuation was introduced. Simulation of the flow with water jet was performed, showing that the water jet weakened the pressure fluctuation in the turbine draft tube effectively. With the increase of the jet flow rate, a greater reduction of pressure fluctuation magnitude was detected, but a decrease of efficiency was found. To keep a balance between pressure fluctuation mitigation and efficiency requirement, 0. 03 ~ 0. 05 times of flow rate at the calculated operating condition was suggested.%选用RNGk-ε湍流模型,对一台混流式模型水轮机在部分负荷工况下的流动进行了全流道三维瞬态湍流数值模拟.数值计算结果与模型试验结果进行了比较,成功预测了水轮机尾水管内压力脉动的幅值与频率特性.从混流式水轮机泄水锥处向尾水管内射水可减弱尾水管内低频压力脉动,对射水后水轮机内的流动进行了数值模拟.计算结果表明,通过射水可以有效减弱尾水管内的压力脉动,减小压力脉动幅值.随着射水量的增加,压力脉动幅值减小更加明显,但是同时会导致水轮机效率的下降.为了尽可能大的减小压力脉动幅值,并兼顾水轮机效率,建议选择0.03~0.05倍该工况流量的射水量.此时,水轮机压力脉动幅值降低明显,而水轮机效率下降不大.

  20. Sensitivity and uncertainty analysis for crop water footprint accounting at a basin level

    Science.gov (United States)

    Zhuo, L.; Mekonnen, M. M.; Hoekstra, A. Y.

    2013-12-01

    Water footprint has been recognized as a comprehensive indicator in water management to evaluate the human pressure on water resources from either production or consumption perspectives. The agricultural sector in particular crop production takes the largest share of the global water footprint. Water footprint of producing unit mass of a crop (m3/ ton) is normally expressed by single volumetric numbers referring to an average value for certain areas and periods. However, the divergence in crop water footprint accounts from different studies, primarily due to the input data quality, may confuse water users and managers. The study investigates the output sensitivity and uncertainty of the green (rainfall) and blue (irrigation water) crop water footprint to key input variables (reference evapotranspiration (ETo), precipitation (PR), crop coefficient (Kc) and crop calendar (D)) at a basin level. A grid-based daily water balance model was applied to compute water footprints of four major crops - maize, rice, soybean and wheat - in the Yellow River basin for 1996-2005 at a 5 by 5 arc minute resolution. Sensitivities of the yearly crop water footprints to individual input variability were assessed by the one-at-a-time (';sensitivity curve') method. Uncertainty in crop water footprint to input uncertainties were quantified through Monte Carlo simulations for selected years 1996 (wet), 2000 (dry) and 2005 (average). Results show that the crop water footprint is most sensitive to ETo and Kc, followed by D and PR. Blue water footprints were more sensitive than green water footprints to input variability. Interestingly, the smaller the annual blue water footprint, the higher its sensitivity to PR, ETo and Kc variability. The uncertainties in total crop water footprints to combined uncertainties in four key input variables was less than × 30% for total water footprints at 95% confidence level. The sensitivity and uncertainty level of crop water footprints also differs with

  1. [Wastewater Quantity and Quality Fluctuation Characteristics of Typical Area of Hybrid Sewage System].

    Science.gov (United States)

    Cheng, Xun; Zhang, Ming-kai; Liu, Yan-chen; Shi, Han-chang

    2016-05-15

    The inflow and infiltration problems cause large fluctuation in wastewater quantity and quality in hybrid sewage system. This seriously challenges the operation and management of sewage system. A multi-point on-line simultaneous monitoring system was established in a typical hybrid sewage system. The key characteristic parameters and their variation features under different circumstances were studied. The result indicated that the daily variation rule was obvious and appeared synchronous among multiple points at normal water level under dry weather flow, but there was no synchronization in conductivity variation among multiple points at high water level under dry weather flow. The statistical distribution range of water level and conductivity was significantly impacted by the seasonal rainfall change under dry weather. The statistical distribution ranges of water level variation rate and conductivity variation rate in specific time were significantly impacted by the rainfall. The response features of water level and conductivity to rainfall intensity and pattern were significantly different under different circumstances. The response sensitivity of conductivity was higher than water level at normal water level and lower at high water level. The database which could support the optimization of operation and management in the hybrid sewage system was proposed based on the distribution law of wastewater quality and quantity fluctuation under dry and wet weather, as well as the variation rate features of wastewater quality and quantity during rainfall obtained using the multi-point on-line simultaneous monitoring system. PMID:27506039

  2. Human impacts on tides overwhelm the effect of sea level rise on extreme water levels in the Rhine-Meuse delta

    NARCIS (Netherlands)

    Vellinga, N. E.; Hoitink, A. J F; van der Vegt, M.; Zhang, W.; Hoekstra, P.

    2014-01-01

    With the aim to link tidal and subtidal water level changes to human interventions, 70. years of water level data for the Rhine-Meuse tidal river network is analysed using a variety of statistical methods. Using a novel parameterization of probability density functions, mean high and low water level

  3. Flood Water Level Mapping and Prediction Due to Dam Failures

    Science.gov (United States)

    Musa, S.; Adnan, M. S.; Ahmad, N. A.; Ayob, S.

    2016-07-01

    Sembrong dam has undergone overflow failure. Flooding has been reported to hit the town, covering an area of up to Parit Raja, located in the district of Batu Pahat. This study aims to identify the areas that will be affected by flood in the event of a dam failure in Sembrong Dam, Kluang, Johor at a maximum level. To grasp the extent, the flood inundation maps have been generated by using the InfoWorks ICM and GIS software. By using these maps, information such as the depth and extent of floods can be identified the main ares flooded. The flood map was created starting with the collection of relevant data such as measuring the depth of the river and a maximum flow rate for Sembrong Dam. The data were obtained from the Drainage and Irrigation Department Malaysia and the Department of Survey and Mapping and HLA Associates Sdn. Bhd. Then, the data were analyzed according to the established Info Works ICM method. The results found that the flooded area were listed at Sri Lalang, Parit Sagil, Parit Sonto, Sri Paya, Parit Raja, Parit Sempadan, Talang Bunut, Asam Bubok, Tanjung Sembrong, Sungai Rambut and Parit Haji Talib. Flood depth obtained for the related area started from 0.5 m up to 1.2 m. As a conclusion, the flood emanating from this study include the area around the town of Ayer Hitam up to Parit Raja approximately of more than 20 km distance. This may give bad implication to residents around these areas. In future studies, other rivers such as Sungai Batu Pahat should be considered for this study to predict and reduce the yearly flood victims for this area.

  4. Monitoring Everglades freshwater marsh water level using L-band synthetic aperture radar backscatter

    Science.gov (United States)

    Kim, Jin-Woo; Lu, Zhong; Jones, John W.; Shum, C.K.; Lee, Hyongki; Jia, Yuanyuan

    2014-01-01

    The Florida Everglades plays a significant role in controlling floods, improving water quality, supporting ecosystems, and maintaining biodiversity in south Florida. Adaptive restoration and management of the Everglades requires the best information possible regarding wetland hydrology. We developed a new and innovative approach to quantify spatial and temporal variations in wetland water levels within the Everglades, Florida. We observed high correlations between water level measured at in situ gages and L-band SAR backscatter coefficients in the freshwater marsh, though C-band SAR backscatter has no close relationship with water level. Here we illustrate the complementarity of SAR backscatter coefficient differencing and interferometry (InSAR) for improved estimation of high spatial resolution water level variations in the Everglades. This technique has a certain limitation in applying to swamp forests with dense vegetation cover, but we conclude that this new method is promising in future applications to wetland hydrology research.

  5. Stochastic modeling of Lake Van water level time series with jumps and multiple trends

    Directory of Open Access Journals (Sweden)

    H. Aksoy

    2013-02-01

    Full Text Available In 1990s, water level in the closed-basin Lake Van located in the Eastern Anatolia, Turkey has risen up about 2 m. Analysis of the hydrometeorological shows that change in the water level is related to the water budget of the lake. In this study, a stochastic model is generated using the measured monthly water level data of the lake. The model is derived after removal of trend and periodicity in the data set. Trend observed in the lake water level time series is fitted by mono- and multiple-trend lines. For the multiple-trend, the time series is first divided into homogeneous segments by means of SEGMENTER, segmentation software. Four segments are found meaningful practically each fitted with a trend line. Two models considering mono- and multiple-trend time series are developed. The multiple-trend model is found better for planning future development in surrounding areas of the lake.

  6. Potential of ENVISAT Radar Altimetry for Water Level Monitoring in the Pantanal Wetland

    Directory of Open Access Journals (Sweden)

    Denise Dettmering

    2016-07-01

    Full Text Available Wetlands are important ecosystems playing an essential role for continental water regulation and the hydrologic cycle. Moreover, they are sensitive to climate changes as well as anthropogenic influences, such as land-use or dams. However, the monitoring of these regions is challenging as they are normally located in remote areas without in situ measurement stations. Radar altimetry provides important measurements for monitoring and analyzing water level variations in wetlands and flooded areas. Using the example of the Pantanal region in South America, this study demonstrates the capability and limitations of ENVISAT radar altimeter for monitoring water levels in inundation areas. By applying an innovative processing method consisting of a rigorous data screening by means of radar echo classification as well as an optimized waveform retracking, water level time series with respect to a global reference and with a temporal resolution of about one month are derived. A comparison between altimetry-derived height variations and six in situ time series reveals accuracies of 30 to 50 cm RMS. The derived water level time series document seasonal height variations of up to 1.5 m amplitude with maximum water levels between January and June. Large scale geographical pattern of water heights are visible within the wetland. However, some regions of the Pantanal show water level variations less than a few decimeter, which is below the accuracies of the method. These areas cannot be reliably monitored by ENVISAT.

  7. Land use water level fluctuation and water quality in two reservoirs subjected to semi-arid climate (Trás-os-Montes, Portugal)

    OpenAIRE

    Geraldes, Ana Maria; Maria José BOAVIDA

    2002-01-01

    Serra Serrada and Azibo reservoirs are located in River Douro watershed. The cLimate is continental, with warm, dry summers and long, cold winters. Precipitation occurs mainly in Autumn and Winter, although in a very irregular regime with wet winters to followed by drought ones.

  8. Analytical approach for determining the mean water level profile in an estuary with substantial fresh water discharge

    Science.gov (United States)

    Cai, Huayang; Savenije, Hubert H. G.; Jiang, Chenjuan; Zhao, Lili; Yang, Qingshu

    2016-03-01

    The mean water level in estuaries rises in the landward direction due to a combination of the density gradient, the tidal asymmetry, and the backwater effect. This phenomenon is more prominent under an increase of the fresh water discharge, which strongly intensifies both the tidal asymmetry and the backwater effect. However, the interactions between tide and river flow and their individual contributions to the rise of the mean water level along the estuary are not yet completely understood. In this study, we adopt an analytical approach to describe the tidal wave propagation under the influence of substantial fresh water discharge, where the analytical solutions are obtained by solving a set of four implicit equations for the tidal damping, the velocity amplitude, the wave celerity, and the phase lag. The analytical model is used to quantify the contributions made by tide, river, and tide-river interaction to the water level slope along the estuary, which sheds new light on the generation of backwater due to tide-river interaction. Subsequently, the method is applied to the Yangtze estuary under a wide range of river discharge conditions where the influence of both tidal amplitude and fresh water discharge on the longitudinal variation of the mean tidal water level is explored. Analytical model results show that in the tide-dominated region the mean water level is mainly controlled by the tide-river interaction, while it is primarily determined by the river flow in the river-dominated region, which is in agreement with previous studies. Interestingly, we demonstrate that the effect of the tide alone is most important in the transitional zone, where the ratio of velocity amplitude to river flow velocity approaches unity. This has to do with the fact that the contribution of tidal flow, river flow, and tide-river interaction to the residual water level slope are all proportional to the square of the velocity scale. Finally, we show that, in combination with extreme

  9. Predicted impacts of future water level decline on monitoring wells using a ground-water model of the Hanford Site

    International Nuclear Information System (INIS)

    A ground-water flow model was used to predict water level decline in selected wells in the operating areas (100, 200, 300, and 400 Areas) and the 600 Area. To predict future water levels, the unconfined aquifer system was stimulated with the two-dimensional version of a ground-water model of the Hanford Site, which is based on the Coupled Fluid, Energy, and Solute Transport (CFEST) Code in conjunction with the Geographic Information Systems (GIS) software package. The model was developed using the assumption that artificial recharge to the unconfined aquifer system from Site operations was much greater than any natural recharge from precipitation or from the basalt aquifers below. However, artificial recharge is presently decreasing and projected to decrease even more in the future. Wells currently used for monitoring at the Hanford Site are beginning to go dry or are difficult to sample, and as the water table declines over the next 5 to 10 years, a larger number of wells is expected to be impacted. The water levels predicted by the ground-water model were compared with monitoring well completion intervals to determine which wells will become dry in the future. Predictions of wells that will go dry within the next 5 years have less uncertainty than predictions for wells that will become dry within 5 to 10 years. Each prediction is an estimate based on assumed future Hanford Site operating conditions and model assumptions

  10. Artificial regulation of water level and its effect on aquatic macrophyte distribution in Taihu Lake.

    Directory of Open Access Journals (Sweden)

    Dehua Zhao

    Full Text Available Management of water levels for flood control, water quality, and water safety purposes has become a priority for many lakes worldwide. However, the effects of water level management on the distribution and composition of aquatic vegetation has received little attention. Relevant studies have used either limited short-term or discrete long-term data and thus are either narrowly applicable or easily confounded by the effects of other environmental factors. We developed classification tree models using ground surveys combined with 52 remotely sensed images (15-30 m resolution to map the distributions of two groups of aquatic vegetation in Taihu Lake, China from 1989-2010. Type 1 vegetation included emergent, floating, and floating-leaf plants, whereas Type 2 consisted of submerged vegetation. We sought to identify both inter- and intra-annual dynamics of water level and corresponding dynamics in the aquatic vegetation. Water levels in the ten-year period from 2000-2010 were 0.06-0.21 m lower from July to September (wet season and 0.22-0.27 m higher from December to March (dry season than in the 1989-1999 period. Average intra-annual variation (CV(a decreased from 10.21% in 1989-1999 to 5.41% in 2000-2010. The areas of both Type 1 and Type 2 vegetation increased substantially in 2000-2010 relative to 1989-1999. Neither annual average water level nor CV(a influenced aquatic vegetation area, but water level from January to March had significant positive and negative correlations, respectively, with areas of Type 1 and Type 2 vegetation. Our findings revealed problems with the current management of water levels in Taihu Lake. To restore Taihu Lake to its original state of submerged vegetation dominance, water levels in the dry season should be lowered to better approximate natural conditions and reinstate the high variability (i.e., greater extremes that was present historically.

  11. Runaway electrons as a diagnostic of plasma internal magnetic fluctuations

    Institute of Scientific and Technical Information of China (English)

    Zheng Yong-Zhen; Ding Xuan-Tong; Li Wen-Zhong

    2006-01-01

    The transport of runaway electrons in a high-temperature plasma is relatively easy to measure in a steady state experiment and a perturbation experiment, which provides runaway electron diffusion coefficient Dr. This diffusion coefficient is determined by internal magnetic fluctuations, so it can be interpreted in terms of a magnetic fluctuation level. The internal magnetic fluctuation level (br/BT) is estimated to be about (2-4)×-4 in the HL-1M plasma. The results presented here demonstrate the effectiveness of using runaway electron transport techniques to determine internal magnetic fluctuations. A profile of magnetic fluctuation level in the HL-1M plasma can be estimated from Dr.

  12. DATA QUALIFICATION REPORT: WATER-LEVEL DATA FROM THE NYE COUNTY EARLY WARNING DRILLING PROGRAM

    International Nuclear Information System (INIS)

    The objective of this work is to evaluate unqualified, water-level data gathered under the Nye County Early Warning Drilling Program (EWDP) and to determine whether the status of the data should be changed to ''qualified'' data in accordance with AP-SIII.2Q (Qualification of Unqualified Data and the Documentation of Rationale for Accepted Data). The corroboration method (as defined in Attachment 2 of AP-SIII.2Q) was implemented to qualify water-level data from Nye County measurements obtained directly from the Nye County Nuclear Waste Repository Program Office (NWRPO). Comparison of United States Geological Survey (USGS) measurements contained in DTN GS990608312312.003 with the Nye County water-level data has shown that the differences in water-level altitudes for the same wells are significantly less than 1 meter. This is an acceptable finding. Evaluation and recommendation criteria have been strictly applied to qualify Nye County measurements of water levels in selected wells measured by the USGS. However, the process of qualifying measured results by corroboration also builds confidence that the Nye County method for measurement of water levels is adequate for the intended use of the data (which is regional modeling). Therefore, it is reasonable to extend the term of ''qualified'' to water-level measurements in the remaining Nye County Phase I wells on the basis that the method has been shown to produce adequate results for the intended purpose of supporting large-scale modeling activities for the Yucca Mountain Project (YMP). The Data Qualification Team recommends the Nye County, water-level data contained in Appendix D of this report be designated as ''qualified''. These data document manual measurements of water-levels in eight (8) EWDP Phase I drillholes that were obtained prior to the field installation of continuous monitoring equipment

  13. Development of simple evaluation tool for water temperature and water level of spent fuel pit. Pit Calculator

    International Nuclear Information System (INIS)

    Before the accident at the Fukushima Daiichi Nuclear Power Station, we had already started to develop a method to predict the water temperature increase in the Spent Fuel Pit (SFP) adequately and simply during the shutdown of cooling systems. In these serial studies, we have carried out prediction of decay heat, calculation of evaporation heat flux from the water surface to the air and three dimensional (3D) thermal hydraulic computations of the SFP water using the computational fluid dynamics (CFD) software. After the accident, we extended the method capability to predict the water level decrease in the SFP during loss of all AC power supplies. 3D computations require a long computing time and its computed results showed that water temperatures were almost uniform outside the rack. This result indicated that a prediction system using one region (1R) calculation model might be able to obtain an average water temperature accurately. From these results, we had developed a simple evaluation tool for water temperature and water level of SFP named 'Pit Calculator'. (author)

  14. Fluctuations in lipid bilayers: Are they understood?

    CERN Document Server

    Schmid, Friederike

    2013-01-01

    We review recent computer simulation studies of undulating lipid bilayers. Theoretical interpretations of such fluctuating membranes are most commonly based on generalized Helfrich-type elastic models, with additional contributions of local "protrusions" and/or density fluctuations. Such models provide an excellent basis for describing the fluctuations of tensionless bilayers in the fluid phase at a quantitative level. However, this description is found to fail for membranes in the gel phase and for membranes subject to high tensions. The fluctuations of tilted gel membranes show a signature of the modulated ripple structure, which is a nearby phase observed in the pretransition regime between the fluid and tilted gel state. This complicates a quantitative analysis on mesoscopic length scales. In the case of fluid membranes under tension, the large-wavelength fluctuation modes are found to be significantly softer than predicted by theory. In the latter context, we also address the general problem of the relat...

  15. Recent reduction in the water level of Lake Victoria has created more habitats for Anopheles funestus

    Directory of Open Access Journals (Sweden)

    Futami Kyoko

    2008-07-01

    Full Text Available Abstract Background The water level of Lake Victoria has fallen more than 1.5 m since 1998, revealing a narrow strip of land along the shore. This study determined whether the recent drop in the water level has created additional breeding grounds for malaria vectors. Methods The recent and past shorelines were estimated using landmarks and a satellite image. The locations of breeding habitats were recorded using a GPS unit during the high and low lake water periods. GIS was used to determine whether the breeding habitats were located on newly emerged land between the new and old shorelines. Results Over half of the breeding habitats existed on newly emerged land. Fewer habitats for the Anopheles gambiae complex were found during the low water level period compared to the high water period. However, more habitats for Anopheles funestus were found during the high water level period, and they were all located on the newly emerged land. Conclusion The recent reduction in water level of Lake Victoria has increased the amount of available habitat for A. funestus. The results suggest that the water drop has substantially affected the population of this malaria vector in the Lake Victoria basin, particularly because the lake has a long shoreline that may harbour many new breeding habitats.

  16. Urban water : harvesting rainwater at household level to improve the current water metabolism in Cuenca, Ecuador

    OpenAIRE

    Godoy Gacha, Juan Diego

    2015-01-01

    With a global population about 7 billion people and their continued growth are pressuring global natural resources, in freshwater matter this pressure is altering both the river flows; timing season of water flows; and spatial patterns in order to meet human demands both in urban as rural areas. However, water stress in urban areas are increasing and expectations by 2050 are grim with a global urban development by 70 percent moreover urbanization rate expected by 2030 in Latin America is 80 p...

  17. Structured singular value synthesis based steam generator water level controller design

    International Nuclear Information System (INIS)

    An uncertainty kinetic model for valve position of feed water to steam generator water level plant was built which can express parameter perturbation and unmodeled dynamic due to operation condition change of steam generator and feed water pump. Robust controller was designed based on structured singular value synthesis method. Robust stability of the water control system can be guaranteed under parameter perturbation and unmodeled dynamic, and robust performance can be acquired via suitable performance weight function. Simulation results show that good control performances are obtained under all combinations of steam generator operation condition and feed water pump operation condition. (authors)

  18. The water level simulation for crane habitat optimization in Xianghai Nature Reserve

    Institute of Scientific and Technical Information of China (English)

    ZHANGYanhong; LIUZhaoli; DENGWei; ZHANGSHuwen; ZHAIJinliang

    2003-01-01

    The probaility of crane living in reedy wetlands can reach 100%, at the same time,the area of reed ,the water level and adjacent water area are main factors which control the crane''''''''s habitat selection.We all know that all these factors are spatially heterogeneous.For the Xianghai wetland safety and to protect the Xianghai wetland habitat of crane,this paper has mainly identified a solution to these problems.The wetland in formation is extracted from the TM images,which reflect the whole wetland landscape and are very important for both quantitative analysis of remote sensing observation of the earth system and positioning analysis in GIS database that is automatically extracted from DEM.The DEM for Xianghai characteristics of topography is created.On the basis of the GRID SUBMODULE,applying the GIS spatial overlay analysis,the relationship between the water level and the reed area below the water level and the rating distribution maps of reed area above water level is established ,When the water level reaches the altitude of 165 n ,the reed area,981.2 ha is maximum,i.e., the water level of 165 m is the optimal.

  19. Fluoride level in drinking water resources of gorgan rural regions, 1385

    Directory of Open Access Journals (Sweden)

    H Rahimzadeh

    2007-01-01

    Full Text Available Background and Objectives: Fluoride is one of the anions existed in water and soil. Its amount is not the same in different kind of water. Since the most of body's need to fluoride should be provided by drinking water, this study was aimed at determining the fluoride level in water supply of Gorgan rural regions. Materials and Methods: In this Cross-Sectional study, the subjects were all 67 water sources of the region. Every season, a one litter Sample was taken in a plastic Container and tested by SPADS Method. After Collecting and encoding the data, ANOVA was used to analyze. Results: The Findings shows that there are 4 springs and 63 wells which are Located in the mountainous (N=16 and flat (N= 47 regions. In every season, the average fluoride Level was lower than Standard Level (1.5 mg/L. The difference between fluoride Level of wells (0.39±0.15mg/L and springs (0.16± 0.13mg/L is Significant (p<0.05 the fluoride Level of mountainous wells is higher than wells located in flat regions (0.13mg/L. This deference was Significant (p<0.05. Conclusion: Based on The results revealing the fluoride Level of drinking water in Gorgan Rural region is less than international Standard, we recommend adding of Supplementary fluoride in foodstuffs of The people Living in This region. Key words: fluoride, drinking water resources, Gorgan, spring

  20. The utility of gravity and water-level monitoring at alluvial aquifer wells in southern Arizona

    Science.gov (United States)

    Pool, D.R.

    2008-01-01

    Coincident monitoring of gravity and water levels at 39 wells in southern Arizona indicate that water-level change might not be a reliable indicator of aquifer-storage change for alluvial aquifer systems. One reason is that water levels in wells that are screened across single or multiple aquifers might not represent the hydraulic head and storage change in a local unconfined aquifer. Gravity estimates of aquifer-storage change can be approximated as a one-dimensional feature except near some withdrawal wells and recharge sources. The aquifer storage coefficient is estimated by the linear regression slope of storage change (estimated using gravity methods) and water-level change. Nonaquifer storage change that does not percolate to the aquifer can be significant, greater than 3 ??Gal, when water is held in the root zone during brief periods following extreme rates of precipitation. Monitor-ing of storage change using gravity methods at wells also can improve understanding of local hydrogeologic conditions. In the study area, confined aquifer conditions are likely at three wells where large water-level variations were accompanied by little gravity change. Unconfined conditions were indicated at 15 wells where significant water-level and gravity change were positively linearly correlated. Good positive linear correlations resulted in extremely large specific-yield values, greater than 0.35, at seven wells where it is likely that significant ephemeral streamflow infiltration resulted in unsaturated storage change. Poor or negative linear correlations indicate the occurrence of confined, multiple, or perched aquifers. Monitoring of a multiple compressible aquifer system at one well resulted in negative correlation of rising water levels and subsidence-corrected gravity change, which suggests that water-level trends at the well are not a good indicatior of overall storage change. ?? 2008 Society of Exploration Geophysicists. All rights reserved.

  1. Impact of sea-level rise on sea water intrusion in coastal aquifers.

    Science.gov (United States)

    Werner, Adrian D; Simmons, Craig T

    2009-01-01

    Despite its purported importance, previous studies of the influence of sea-level rise on coastal aquifers have focused on specific sites, and a generalized systematic analysis of the general case of the sea water intrusion response to sea-level rise has not been reported. In this study, a simple conceptual framework is used to provide a first-order assessment of sea water intrusion changes in coastal unconfined aquifers in response to sea-level rise. Two conceptual models are tested: (1) flux-controlled systems, in which ground water discharge to the sea is persistent despite changes in sea level, and (2) head-controlled systems, whereby ground water abstractions or surface features maintain the head condition in the aquifer despite sea-level changes. The conceptualization assumes steady-state conditions, a sharp interface sea water-fresh water transition zone, homogeneous and isotropic aquifer properties, and constant recharge. In the case of constant flux conditions, the upper limit for sea water intrusion due to sea-level rise (up to 1.5 m is tested) is no greater than 50 m for typical values of recharge, hydraulic conductivity, and aquifer depth. This is in striking contrast to the constant head cases, in which the magnitude of salt water toe migration is on the order of hundreds of meters to several kilometers for the same sea-level rise. This study has highlighted the importance of inland boundary conditions on the sea-level rise impact. It identifies combinations of hydrogeologic parameters that control whether large or small salt water toe migration will occur for any given change in a hydrogeologic variable. PMID:19191886

  2. Hadronic Correlations and Fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Volker

    2008-10-09

    We will provide a review of some of the physics which can be addressed by studying fluctuations and correlations in heavy ion collisions. We will discuss Lattice QCD results on fluctuations and correlations and will put them into context with observables which have been measured in heavy-ion collisions. Special attention will be given to the QCD critical point and the first order co-existence region, and we will discuss how the measurement of fluctuations and correlations can help in an experimental search for non-trivial structures in the QCD phase diagram.

  3. Fluctuations of Mediterranean outflow water circulation in the Gulf of Cadiz during MIS 5 to 7: Evidence from benthic foraminiferal assemblage and stable isotope records

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.D.; Rai, A.K.; Tiwari, M.; Naidu, P.D.; Verma, K.; Chaturvedi, M.; Niyogi, A.; Pandey, D.

    Water) between 600 and 1200 m (Zenk and Armi, 1990; Baringer, 1993). The MOW water mass flows above the North Atlantic Deep Water (NADW). 4    3. Material and Methodology The IODP site U1387 (36048.321’N; 7043.1321’W; water depth 559.1 mbsl...

  4. DAHITI - An Innovative Approach for Estimating Water Level Time Series over Inland Water using Multi-Mission Satellite Altimetry

    Science.gov (United States)

    Schwatke, Christian; Dettmering, Denise

    2016-04-01

    Satellite altimetry has been designed for sea level monitoring over open ocean areas. However, for some years, this technology has also been used to retrieve water levels from lakes, reservoirs, rivers, wetlands and in general any inland water body. In this contribution, a new approach for the estimation of inland water level time series is presented. The method is the basis for the computation of time series of rivers and lakes available through the web service 'Database for Hydrological Time Series over Inland Water' (DAHITI). It is based on an extended outlier rejection and a Kalman filter approach incorporating cross-calibrated multi-mission altimeter data from Envisat, ERS-2, Jason-1, Jason-2, Topex/Poseidon, and SARAL/AltiKa, including their uncertainties. The new approach yields RMS differences with respect to in situ data between 4 cm and 36 cm for lakes and 8 cm and 114 cm for rivers, respectively. Within this presentation, the new approach will be introduced and examples for water level time series for a variety of lakes and rivers will be shown featuring different characteristics such as shape, lake extent, river width, and data coverage. A comprehensive validation is performed by comparisons with in situ gauge data and results from external inland altimeter databases.

  5. Rhizosphere dynamics of two riparian plant species from the water fluctuation zone of Three Gorges Reservoir, P.R. China - pH, oxygen and LMWOA monitoring during short flooding events

    Science.gov (United States)

    Schreiber, Christina M.; Schurr, Ulrich; Zeng, Bo; Höltkemeier, Agnes; Kuhn, Arnd J.

    2010-05-01

    Since the construction of the Three Gorges Dam at the Yangtze River in China, the reservoir management created a new 30m water fluctuation zone 45-75m above the original water level. Only species well adapted to long-time flooding (up to several months) will be able to vegetate the river banks and replace the original vegetation. To investigate how common species of the riverbanks cope with submergence, Alternanthera philoxeroides Mart. and Arundinella anomala Steud., two flooding resistant riparian species, have been examined in a rhizotron environment. Short-time (2 days waterlogging, 2 days flooding, 2 days recovery) flooding cycles in the original substrate and long time (14 days waterlogging, flooding, recovery) flooding cycles, in original substrate and sterile glass bead substrate, have been simulated in floodable two-way access rhizotrons. Oxygen- and pH-sensitive foils (planar optodes, PreSens) automatically monitored root reaction in a confined space (2cm2 each) on the backside of the rhizotron, while soil solution samples were taken 2 times a day from the other side of the rhizotron at the corresponding area through filter and steel capillaries. The samples were analyzed by capillary electrophoresis for low molecular weight organic acids (LMWOA, i.e. oxalic, formic, succinic, malic, acetic, glyoxylic, lactic and citric acid). Results show diurnal rhythms of rhizospheric acidification for both species in high resolution, combined with oxygen entry into the root surrounding during waterlogged state. Flooding caused stronger acidification in the rhizosphere, that were however not accompanied by increased occurrence of LMWOA except for acetic and glyoxylic acid. First results from longer flooding periods show stable diurnal rhythms during waterlogging, but no strongly increased activity during the flooding event. Performance of the two species is not hampered by being waterlogged, and they follow a silencing strategy during a longer phase of anoxia without

  6. Quantitative Assay and Evaluation of Uranium Levels in Water Resources of Egypt

    International Nuclear Information System (INIS)

    Quality of water resources are one of the vital components for industrial, agricultural and economical development as well as for security issue. The aim of this study is to evaluate the levels of uranium in the Egyptian water resources used for drinking purposes. Fifty-seven water samples representing Egyptian water resources for drinking water (unpurified, purified, tap and ground) were collected. Sensitive and rapid destructive laser fluorimetry technique was used for uranium determination. The results showed that the level of uranium in most of the collected samples was below than the safe limit recommended by the international organizations. The average annual equivalent dose due to the consumption of water ranged from 0.1 μSv/y to 2.0 μSv/y which is lower than the international recommendation

  7. HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients V007

    Data.gov (United States)

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCH2O) contains the entire mission (~3 years) of HIRDLS data...

  8. Anatomic adaptation of seedlings of woody plants to various levels of soil water supply

    OpenAIRE

    I. P. Grigoryuk; V. I. Tkachov; P. P. Yavorivskyi

    2005-01-01

    Tree seedlings anatomical parameters adaptation to different soil water supply levels were studied. Differences in stomata number and shape and fiber length for leaf-bearing species and central cylinder area for coniferous species have been determined.

  9. Great Lakes Daily Ice Observations at NOAA Water Level Gauge Sites

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains daily visual ice observations taken yearly from 1 November to 30 April at NOAA/National Ocean Service water level gauge sites in the Great...

  10. Back-Analyses of Landfill Instability Induced by High Water Level: Case Study of Shenzhen Landfill

    Directory of Open Access Journals (Sweden)

    Ren Peng

    2016-01-01

    Full Text Available In June 2008, the Shenzhen landfill slope failed. This case is used as an example to study the deformation characteristics and failure mode of a slope induced by high water levels. An integrated monitoring system, includ