Science.gov

Sample records for field water balances

  1. Field water balance of landfill final covers.

    PubMed

    Albright, William H; Benson, Craig H; Gee, Glendon W; Roesler, Arthur C; Abichou, Tarek; Apiwantragoon, Preecha; Lyles, Bradley F; Rock, Steven A

    2004-01-01

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into underlying waste. Conventional covers employing resistive barriers as well as alternative covers relying on water-storage principles were monitored in large (10 x 20 m), instrumented drainage lysimeters over a range of climates at 11 field sites in the United States. Surface runoff was a small fraction of the water balance (0-10%, 4% on average) and was nearly insensitive to the cover slope, cover design, or climate. Lateral drainage from internal drainage layers was also a small fraction of the water balance (0-5.0%, 2.0% on average). Average percolation rates for the conventional covers with composite barriers (geomembrane over fine soil) typically were less than 12 mm/yr (1.4% of precipitation) at humid locations and 1.5 mm/yr (0.4% of precipitation) at arid, semiarid, and subhumid locations. Average percolation rates for conventional covers with soil barriers in humid climates were between 52 and 195 mm/yr (6-17% of precipitation), probably due to preferential flow through defects in the soil barrier. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% of precipitation) in humid climates and generally less than 2.2 mm/yr (0.4% of precipitation) in arid, semiarid, and subhumid climates. One-half (five) of the alternative covers in arid, semiarid, and subhumid climates transmitted less than 0.1 mm of percolation, but two transmitted much more percolation (26.8 and 52 mm) than anticipated during design. The data collected support conclusions from other studies that detailed, site-specific design procedures are very important for successful performance of alternative landfill covers. PMID:15537955

  2. Landscape-Scale water balance of cotton fields

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information on the temporal and spatial distribution of the components of the water balance of a production field is necessary to manage agronomic inputs. Furthermore, factors that determine crop yield require knowledge of the energy, water, nutrient and carbon balance and their interaction. The in...

  3. Equations for drainage component of the field water balance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate estimates of the drainage component of the field water balance are needed to achieve improved management of drainage in irrigated crop production systems and obtain improved estimates of evapotranspiration (ET) from soil water measurements. Estimating drainage for numerous soil and field co...

  4. Field Water Balance of Landfill Final Covers

    EPA Science Inventory

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into unde...

  5. Balancing the interactions of ions, water, and DNA in the Drude polarizable force field.

    PubMed

    Savelyev, Alexey; MacKerell, Alexander D

    2014-06-19

    Recently we presented a first-generation all-atom Drude polarizable force field for DNA based on the classical Drude oscillator model, focusing on optimization of key dihedral angles followed by extensive validation of the force field parameters. Presently, we describe the procedure for balancing the electrostatic interactions between ions, water, and DNA as required for development of the Drude force field for DNA. The proper balance of these interactions is shown to impact DNA stability and subtler conformational properties, including the conformational equilibrium between the BI and BII states, and the A and B forms of DNA. The parametrization efforts were simultaneously guided by gas-phase quantum mechanics (QM) data on small model compounds and condensed-phase experimental data on the hydration and osmotic properties of biologically relevant ions and their solutions, as well as theoretical predictions for ionic distribution around DNA oligomer. In addition, fine-tuning of the internal base parameters was performed to obtain the final DNA model. Notably, the Drude model is shown to more accurately reproduce counterion condensation theory predictions of DNA charge neutralization by the condensed ions as compared to the CHARMM36 additive DNA force field, indicating an improved physical description of the forces dictating the ionic solvation of DNA due to the explicit treatment of electronic polarizability. In combination with the polarizable DNA force field, the availability of Drude polarizable parameters for proteins, lipids, and carbohydrates will allow for simulation studies of heterogeneous biological systems. PMID:24874104

  6. Balancing the Interactions of Ions, Water, and DNA in the Drude Polarizable Force Field

    PubMed Central

    2015-01-01

    Recently we presented a first-generation all-atom Drude polarizable force field for DNA based on the classical Drude oscillator model, focusing on optimization of key dihedral angles followed by extensive validation of the force field parameters. Presently, we describe the procedure for balancing the electrostatic interactions between ions, water, and DNA as required for development of the Drude force field for DNA. The proper balance of these interactions is shown to impact DNA stability and subtler conformational properties, including the conformational equilibrium between the BI and BII states, and the A and B forms of DNA. The parametrization efforts were simultaneously guided by gas-phase quantum mechanics (QM) data on small model compounds and condensed-phase experimental data on the hydration and osmotic properties of biologically relevant ions and their solutions, as well as theoretical predictions for ionic distribution around DNA oligomer. In addition, fine-tuning of the internal base parameters was performed to obtain the final DNA model. Notably, the Drude model is shown to more accurately reproduce counterion condensation theory predictions of DNA charge neutralization by the condensed ions as compared to the CHARMM36 additive DNA force field, indicating an improved physical description of the forces dictating the ionic solvation of DNA due to the explicit treatment of electronic polarizability. In combination with the polarizable DNA force field, the availability of Drude polarizable parameters for proteins, lipids, and carbohydrates will allow for simulation studies of heterogeneous biological systems. PMID:24874104

  7. Skylab water balance analysis

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.

    1977-01-01

    The water balance of the Skylab crew was analyzed. Evaporative water loss using a whole body input/output balance equation, water, body tissue, and energy balance was analyzed. The approach utilizes the results of several major Skylab medical experiments. Subsystems were designed for the use of the software necessary for the analysis. A partitional water balance that graphically depicts the changes due to water intake is presented. The energy balance analysis determines the net available energy to the individual crewman during any period. The balances produce a visual description of the total change of a particular body component during the course of the mission. The information is salvaged from metabolic balance data if certain techniques are used to reduce errors inherent in the balance method.

  8. Botswana water and surface energy balance research program. Part 1: Integrated approach and field campaign results

    NASA Technical Reports Server (NTRS)

    Vandegriend, A. A.; Owe, M.; Vugts, H. F.; Ramothwa, G. K.

    1992-01-01

    The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. Results of the first part of the program (Botswana 1) which ran from 1 Jan. 1988 - 31 Dec. 1990 are summarized. Botswana 1 consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components in general are described and activities performed during the surface energy modeling component including the extensive field campaign are summarized. The results of the passive microwave component are summarized. The key of the field campaign was a multilevel approach, whereby measurements by various similar sensors were made at several altitudes and resolution. Data collection was performed at two adjacent sites of contrasting surface character. The following measurements were made: micrometeorological measurements, surface temperatures, soil temperatures, soil moisture, vegetation (leaf area index and biomass), satellite data, aircraft data, atmospheric soundings, stomatal resistance, and surface emissivity.

  9. Urbanization dramatically altered the water balances of a paddy field dominated basin in Southern China

    NASA Astrophysics Data System (ADS)

    Hao, L.; Sun, G.; Liu, Y.; Wan, J.; Qin, M.; Qian, H.; Liu, C.; John, R.; Fan, P.; Chen, J.

    2015-02-01

    Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration) to a large population globally. However, these benefits are declining as a result of rapid environmental and socioeconomic transformations characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of streamflow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River Basin in southern China where massive industrialization has occurred in the region during the past three decades. We found that streamflow increased by 58% and evapotranspiration (ET) decreased by 23% during 1986-2013 as a result of an increase in urban areas of three folds and reduction of rice paddy field by 27%. Both highflows and lowflows increased significantly by about 28% from 2002 to 2013. The increases in streamflow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS data. The reduction in ET and increase in streamflow was attributed to the large cropland conversion that overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from a water-dominated to a human-dominated landscape, and thus was considered as one of the extreme types of contemporary hydrologic disturbances. The ongoing large-scale urbanization in the rice paddy-dominated regions in the humid southern China, and East Asia, will likely elevate stormflow volume, aggravate flood risks, and intensify urban heat island effects. Understanding the linkage between land use change and changes in hydrological processes is essential for better management of urbanizing watersheds.

  10. Water balance above the mountain front: Integrating hydrologic modeling and field studies

    NASA Astrophysics Data System (ADS)

    Boyle, D.; McConnell, J.; Hobson, A.; Gorham, T.

    2003-04-01

    Faculty and students at the Desert Research Institute (DRI) are conducting SAHRA-related research aimed at (1) understanding the spatial and temporal distribution of snow cover and water balance above the mountain front and (2) developing and calibrating both operational and physically based numerical models that can be used to predict the quantity and timing of runoff in semi-arid regions where the majority of runoff originates in the seasonal snow pack. The headwaters of the Rio Grande above the USGS stream gage at Del Norte, CO is the primary focus of current field and modeling efforts. The USGS Modular Modeling System (MMS), GIS Weasel, Precipitation-Runoff Modeling System (PRMS), and XYZ snow distribution model together provide a platform for integrating field and modeling studies. For example, we use up-to-date model simulations, with the model calibrated to surface flows measured at the Del Norte gage, to provide detailed, time-specific estimates of the spatial distribution of snow water equivalents an

  11. Functional evaluation of the field capacity concept for water balance analysis under climatic seasonality conditions

    NASA Astrophysics Data System (ADS)

    Ceres, Francesca; Battista Chirico, Giovanni; Romano, Nunzio

    2010-05-01

    Some types of hydrologic models, such as the bucket model, rely on the concept of field water capacity, θFWC. In this study, the techniques traditionally proposed for determining this parameter have been critically analyzed in terms of their effectiveness in computing soil water budget. Two basic aspects of the problem will be presented: (i) to set up techniques for a suitable parameterization of hydrologic models, (ii) to implement simulation models that describe the various processes with different levels of complexity and compare their results. The following models are considered: the Richards equation based model and the simplified bucket-type model. Soil water content at the condition of field capacity has been determined for both uniform and layered soil profiles by using the numerical model developed by Romano et al. (1998) and verified by Brunone et al. (2003). This model solves the Richards equation with the Crank-Nicolson finite difference technique and uses a numerical algorithm specifically designed in case of layered soils for calculating the hydraulic conductivity at the layer interface. For layered soil profiles, which actually represent the rule rather than an exception, soil layer sequence and the reciprocal differences in the soil hydraulic properties (soil water retention and hydraulic conductivity functions) strongly influence the attainment of the field capacity condition. Simulations of soil water balance using the Richards-based model or the bucket-type model have been compared. It is shown that climatic seasonality typical of the Mediterranean environments exerts some influence on the dynamics of surficial water contents in soil and this influence can be kept only in part by the bucket model if not parameterized adequately. Rainfall variability during the vegetative season and that one evolving during the quiescent phase is responsible for different transpiration conditions and for evolutions of the water content in the soil characterized

  12. Urbanization dramatically altered the water balances of a paddy field-dominated basin in southern China

    NASA Astrophysics Data System (ADS)

    Hao, L.; Sun, G.; Liu, Y.; Wan, J.; Qin, M.; Qian, H.; Liu, C.; Zheng, J.; John, R.; Fan, P.; Chen, J.

    2015-07-01

    Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration) to a large population globally. However, these benefits are diminishing as a result of rapid environmental and socioeconomic transformations, characterized by population growth, urbanization, and climate change in many Asian countries. This case study examined the responses of stream flow and watershed water balances to the decline of rice paddy fields due to urbanization in the Qinhuai River basin in southern China, where massive industrialization has occurred during the past 3 decades. We found that stream flow increased by 58 % and evapotranspiration (ET) decreased by 23 % during 1986-2013 as a result of a three-fold increase in urban areas and a reduction of rice paddy fields by 27 %. Both high flows and low flows increased significantly by about 28 % from 2002 to 2013. The increases in stream flow were consistent with the decreases in ET and leaf area index monitored by independent remote sensing MODIS (Moderate Resolution Imaging Spectroradiometer) data. Attribution analysis, based on two empirical models, indicated that land-use/land-cover change contributed about 82-108 % of the observed increase in stream flow from 353 ± 287 mm yr-1 during 1986-2002 to 556 ± 145 during 2003-2013. We concluded that the reduction in ET was largely attributed to the conversion of cropland to urban use. The effects of land-use change overwhelmed the effects of regional climate warming and climate variability. Converting traditional rice paddy fields to urban use dramatically altered land surface conditions from an artificial wetland-dominated landscape to an urban land-use- dominated one, and thus was considered an extreme type of contemporary hydrologic disturbance. The ongoing large-scale urbanization of the rice paddy-dominated regions, in humid southern China and East Asia, will likely elevate storm-flow volume, aggravate flood risks, and intensify urban

  13. Estimation of Actual Crop ET of Paddy Using the Energy Balance Model SMARET and Validation with Field Water Balance Measurements and a Crop Growth Model (ORYZA)

    NASA Astrophysics Data System (ADS)

    Nallasamy, N. D.; Muraleedharan, B. V.; Kathirvel, K.; Narasimhan, B.

    2014-12-01

    Sustainable management of water resources requires reliable estimates of actual evapotranspiration (ET) at fine spatial and temporal resolution. This is significant in the case of rice based irrigation systems, one of the major consumers of surface water resources and where ET forms a major component of water consumption. However huge tradeoff in the spatial and temporal resolution of satellite images coupled with lack of adequate number of cloud free images within a growing season act as major constraints in deriving ET at fine spatial and temporal resolution using remote sensing based energy balance models. The scale at which ET is determined is decided by the spatial and temporal scale of Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI), which form inputs to energy balance models. In this context, the current study employed disaggregation algorithms (NL-DisTrad and DisNDVI) to generate time series of LST and NDVI images at fine resolution. The disaggregation algorithms aimed at generating LST and NDVI at finer scale by integrating temporal information from concurrent coarse resolution data and spatial information from a single fine resolution image. The temporal frequency of the disaggregated images is further improved by employing composite images of NDVI and LST in the spatio-temporal disaggregation method. The study further employed half-hourly incoming surface insolation and outgoing long wave radiation obtained from the Indian geostationary satellite (Kalpana-1) to convert the instantaneous ET into daily ET and subsequently to the seasonal ET, thereby improving the accuracy of ET estimates. The estimates of ET were validated with field based water balance measurements carried out in Gadana, a subbasin predominated by rice paddy fields, located in Tamil Nadu, India.

  14. Par Pond water balance

    SciTech Connect

    Hiergesell, R.A.; Dixon, K.L.

    1996-06-01

    A water budget for the Par Pond hydrologic system was established in order to estimate the rate of groundwater influx to Par Pond. This estimate will be used in modeling exercises to predict Par Pond reservoir elevation and spillway discharge in the scenario where Savannah River water is no longer pumped and discharged into Par Pond. The principal of conservation of mass was used to develop the water budget, where water inflow was set equal to water outflow. Components of the water budget were identified, and the flux associated with each was determined. The water budget was considered balanced when inflow and outflow summed to zero. The results of this study suggest that Par Pond gains water from the groundwater system in the upper reaches of the reservoir, but looses water to the groundwater system near the dam. The rate of flux of groundwater from the water table aquifer into Par Pond was determined to be 13 cfs. The rate of flux from Par Pond to the water table aquifer near the dam was determined to be 7 cfs.

  15. 3-D modeling of water balance and soil erosion in a clayey subsurface drained agricultural field in boreal climate

    NASA Astrophysics Data System (ADS)

    Turunen, M.; Warsta, L.; Koivusalo, H. J.; Paasonen-Kivekäs, M.; Nurminen, J.; Myllys, M.; Alakukku, L.; Äijö, H.; Puustinen, M.

    2012-12-01

    Fluxes of nutrients and other substances from cultivated fields cause eutrophication and deterioration of water quality in aquatic ecosystems worldwide. In order to develop effective strategies to control the environmental impacts of crop cultivation, it is crucial to identify the main transport pathways and the effects of different water management methods on the loads. Reduction of sediment loads is essential since sediment particles typically carry nutrients (especially sorbed phosphorus) and other potentially harmful substances, e.g. pesticides, from the fields to the adjacent surface waters. The novel part of this study was the investigation of suspended sediment transport in soil macropores to the subsurface drains and to the deep groundwater. We applied a 3-D distributed dual-permeability model (FLUSH) using a dataset collected from a subsurface drained, clayey agricultural field (15 ha) to holistically assess water balance, soil erosion and sediment transport from the field to an adjacent stream. The data set included five years of hydrological and water quality measurements from four intensively monitored field sections with different soil properties, topography, drainage systems (drain spacing and drain depth), drain installation methods (trenchless and trench drainage) and drain envelope materials (gravel and fiber). The 3-D model allowed us to quantify how soil erosion and sediment transport differed between the field sections within the field area. The simulations were conducted during snow- and frost-free periods. The simulation results include closure of water balance of the cultivated field, distribution of soil erosion and sediment transport within the field area and the effects of different subsurface drainage systems on sediment loads. The 3-D dual-permeability subsurface flow model was able to reproduce the measured drainflows and sediment fluxes in the clayey field and according to the simulations over 90% of drainflow waters were conveyed to

  16. Student Performance in Water Pouring and Balance Beam Tasks: Effect of Manipulation of Perceptual Field Factor.

    ERIC Educational Resources Information Center

    Niaz, Mansoor

    1988-01-01

    The effect of manipulation of the perceptual field factors on undergraduate student performance in proportional reasoning tasks was investigated. Evidence was found to support the hypothesis that the manipulation of the perceptual field factor can affect student performance. Reports data correlated with the Group Embedded-Figures Test. (CW)

  17. Influence of potential evapotranspiration on the water balance of sugarcane fields in Maui, Hawaii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The year-long warm temperatures and other climatic characteristics of the Pacific Ocean Islands have made Hawaii an optimum place for growing sugarcane; however, irrigation is essential to satisfy the large water demand of sugarcane. Under the Hawaiian tropical weather, actual evapotranspiration (A...

  18. Skylab water balance error analysis

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.

    1977-01-01

    Estimates of the precision of the net water balance were obtained for the entire Skylab preflight and inflight phases as well as for the first two weeks of flight. Quantitative estimates of both total sampling errors and instrumentation errors were obtained. It was shown that measurement error is minimal in comparison to biological variability and little can be gained from improvement in analytical accuracy. In addition, a propagation of error analysis demonstrated that total water balance error could be accounted for almost entirely by the errors associated with body mass changes. Errors due to interaction between terms in the water balance equation (covariances) represented less than 10% of the total error. Overall, the analysis provides evidence that daily measurements of body water changes obtained from the indirect balance technique are reasonable, precise, and relaible. The method is not biased toward net retention or loss.

  19. Simulation of water balance in a clayey, subsurface drained agricultural field with three-dimensional FLUSH model

    NASA Astrophysics Data System (ADS)

    Warsta, Lassi; Karvonen, Tuomo; Koivusalo, Harri; Paasonen-Kivekäs, Maija; Taskinen, Antti

    2013-01-01

    SummaryWater flow is a key component in the evaluation of soil erosion and nutrient loads from agricultural fields. Field cultivation is the main non-point pollution source threatening water quality of surface waters in Nordic and many other countries. Few models exist that can describe key hydrological processes in clayey soils, i.e. overland flow, preferential flow in macropores and soil shrinkage and swelling. A new three-dimensional (3-D) distributed numerical model called FLUSH is introduced in this study to simulate these processes. FLUSH describes overland flow with the diffuse wave simplification of the Saint Venant equations and subsurface flow with a dual-permeability approach using the Richards equation in both macropore and matrix pore systems. A method based on the pentadiagonal matrix algorithm solves flow in both macropore and matrix systems directly in a column of cells in the computational grid. Flow between the columns is solved with iteration accelerated with OpenMP parallelisation. The model validity is tested with data from a 3-D analytical model and a clayey subsurface drained agricultural field in southern Finland. According to the simulation results, over 99% of the drainflow originated from the macropore system and drainflow started in some cases within the same hour when precipitation started indicating preferential flow in the profile. The moisture content of the clay soil had a profound effect on runoff distribution between surface runoff and drainflow. In summer, when the soil was dry and cracked, drainflow dominated the total runoff, while in autumn, when the shrinkage crack network had swollen shut, surface runoff fraction clearly increased. Observed differences in surface runoff fraction before and after tillage indicated that the operation decreased hydraulic conductivity of the profile.

  20. Field balancing in the real world

    SciTech Connect

    Bracher, B.

    1997-09-05

    Field balancing can achieve significant results when other problems are present in the frequency spectrum and multiple vibrations are evident in the waveform. Many references suggest eliminating other problems before attempting to balance. That`s great - if you can do it. There are valid reasons for this approach, and it would be much easier to balance machinery when other problems have been corrected. It is the theoretical ideal in field balancing. However, in the real world of machinery maintained for years by reacting to immediate problems, the classic vibration signature for unbalance is rarely seen. Maintenance personnel make most of their decisions with limited information. The decision to balance or not to balance is usually made the same way. This paper will demonstrate significant results of field balancing in the presence of multiple problems. By examining the data available and analyzing the probabilities, a reasonable chance for success can be assured.

  1. Field measurement of seepage and evapotranspiration rate for a soil under plant cover: A comparison of soil water balance and tritium labeling procedure

    NASA Astrophysics Data System (ADS)

    Kreutzer, K.; Strebel, O.; Renger, M.

    1980-08-01

    Vertical water flux at 90 cm depth and evapotranspiration were measured in a loess Parabraunerde soil profile, under spring wheat and sugar beets, respectively, during a time period of nearly 21 months. Two field methods were compared: the HTO-tracer method (labeling soil water at a depth of 60 cm followed by core sampling) and the soil water balance method (measuring soil water suction and water content as a function of depth and time). Outside the vegetation season the results of the two methods agreed well, but not during the vegetation season. The reason is that the reference soil compartment, with its reference depth of 90 cm, lies within the root zone and the HTO-method does not correctly reflect the water flux through the roots and the water withdrawal by the roots from this reference compartment. It is shown, that after correcting the HTO-values for these root-activity-dependent effects, a good agreement between the two methods was found also during periods with root activity. Investigations with the HTO-method lead to inaccurate results if the reference depth or the median value of the tracer distribution lie within the zone of active roots.

  2. Water balance model for Kings Creek

    NASA Technical Reports Server (NTRS)

    Wood, Eric F.

    1990-01-01

    Particular attention is given to the spatial variability that affects the representation of water balance at the catchment scale in the context of macroscale water-balance modeling. Remotely sensed data are employed for parameterization, and the resulting model is developed so that subgrid spatial variability is preserved and therefore influences the grid-scale fluxes of the model. The model permits the quantitative evaluation of the surface-atmospheric interactions related to the large-scale hydrologic water balance.

  3. [Disorders in sodium-water balance].

    PubMed

    Petitclerc, Thierry

    2013-02-01

    Water balance control is aimed at normalizing cellular hydration, and sodium balance control at normalizing extracellular volume. Water balance control is based on the regulation of body fluid tonicity, while the control of sodium balance is based on the regulation of effective arterial volume. Disorders of water balance act on cellular hydration: primary disorders induce a proportional change in tonicity; secondary disorders are induced by a change in tonicity or effective arterial volume. Disorders of sodium balance act on extracellular volume: primary disorders of sodium balance induce a change in effective arterial volume; secondary disorders are induced by a change in effective arterial volume. Physical examination of the patient allows assessing the extracellular volume and the severity of the sodium balance disorder. Natremia - that generally reflects tonicity - allows to assess cellular hydration and to determine the type of water balance disorder. In the case of natremia disturbance, the assessment of both the tonicity and the extracellular volume allows the determination of the type of water and/or sodium balance disorder that is necessary for prescribing the adequate therapy. PMID:23177272

  4. Analyzing hydrological sustainability through water balance.

    PubMed

    Menció, Anna; Folch, Albert; Mas-Pla, Josep

    2010-05-01

    The objective of the Water Framework Directive (2000/60/EC) is to assist in the development of management plans that will lead to the sustainable use of water resources in all EU member states. However, defining the degree of sustainability aimed at is not a straightforward task. It requires detailed knowledge of the hydrogeological characteristics of the basin in question, its environmental needs, the amount of human water demand, and the opportunity to construct a proper water balance that describes the behavior of the hydrological system and estimates available water resources. An analysis of the water balance in the Selva basin (Girona, NE Spain) points to the importance of regional groundwater fluxes in satisfying current exploitation rates, and shows that regional scale approaches are often necessary to evaluate water availability. In addition, we discuss the pressures on water resources, and analyze potential actions, based on the water balance results, directed towards achieving sustainable water management in the basin. PMID:20229067

  5. Population and water resources: a delicate balance.

    PubMed

    Falkenmark, M; Widstrand, C

    1992-11-01

    Various avenues exist to minimize the effects of the current water crisis in some regions of the world and the more widespread problems that will threaten the world in the future. Active management of existing water resources and a reduction in population growth in water-scarce areas are needed to minimize the effects of the water crisis. National boundaries do not effect water systems. Cooperation and commitment of local, national, and international governments, institutions, and other organizations are needed to manage water systems. Development in each country must entail conscientious and effective balancing of unavoidable manipulations of the land and the unavoidable environmental impacts of those manipulations. The conditions of environmental sustainability must include protection of land productivity, ground water potability, and biodiversity. Humans must deal with these factors either by adopting methods to protect natural systems or by correcting existing damage and reducing future problems. They need to understand the demographic forces in each country so they can balance society's rising needs for clean water with the finite amount of water available. Factors affecting future needs at all levels include rapid rural-urban migration, high fertility, and changing patterns of international population movement. Given an increased awareness of global water systems, demographic trends, and active management of resources, the fragile balance between population and water can be maintained. PMID:12344702

  6. Water and sodium balance in space.

    PubMed

    Drummer, C; Norsk, P; Heer, M

    2001-09-01

    We have previously shown that fluid balances and body fluid regulation in microgravity (microG) differ from those on Earth (Drummer et al, Eur J Physiol 441:R66-R72, 2000). Arriving in microG leads to a redistribution of body fluid-composed of a shift of fluid to the upper part of the body and an exaggerated extravasation very early in-flight. The mechanisms for the increased vascular permeability are not known. Evaporation, oral hydration, and urinary fluid excretion, the major components of water balance, are generally diminished during space flight compared with conditions on Earth. Nevertheless, cumulative water balance and total body water content are stable during flight if hydration, nutritional energy supply, and protection of muscle mass are at an acceptable level. Recent water balance data disclose that the phenomenon of an absolute water loss during space flight, which has often been reported in the past, is not a consequence of the variable microG. The handling of sodium, however, is considerably affected by microG. Sodium-retaining endocrine systems, such as renin-aldosterone and catecholamines, are much more activated during microG than on Earth. Despite a comparable oral sodium supply, urinary sodium excretion is diminished and a considerable amount of sodium is retained-without accumulating in the intravascular space. An enormous storage capacity for sodium in the extravascular space and a mechanism that allows the dissociation between water and sodium handling likely contribute to the fluid balance adaptation in weightlessness. PMID:11532707

  7. Virtual water balance estimation in Tunisia

    NASA Astrophysics Data System (ADS)

    Stambouli, Talel; Benalaya, Abdallah; Ghezal, Lamia; Ali, Chebil; Hammami, Rifka; Souissi, Asma

    2015-04-01

    The water in Tunisia is limited and unevenly distributed in the different regions, especially in arid zones. In fact, the annual rainfall average varies from less than 100 mm in the extreme South to over 1500 mm in the extreme North of the country. Currently, the conventional potential of water resources of the country is estimated about 4.84 billion m³ / year of which 2.7 billion cubic meters / year of surface water and 2.14 billion cubic meters / year of groundwater, characterizing a structural shortage for water safety in Tunisia (under 500m3/inhabitant/year). With over than 80% of water volumes have been mobilized for agriculture. The virtual water concept, defined by Allan (1997), as the amount of water needed to generate a product of both natural and artificial origin, this concept establish a similarity between product marketing and water trade. Given the influence of water in food production, virtual water studies focus generally on food products. At a global scale, the influence of these product's markets with water management was not seen. Influence has appreciated only by analyzing water-scarce countries, but at the detail level, should be increased, as most studies consider a country as a single geographical point, leading to considerable inaccuracies. The main objective of this work is the virtual water balance estimation of strategic crops in Tunisia (both irrigated and dry crops) to determine their influence on the water resources management and to establish patterns for improving it. The virtual water balance was performed basing on farmer's surveys, crop and meteorological data, irrigation management and regional statistics. Results show that the majority of farmers realize a waste of the irrigation water especially at the vegetable crops and fruit trees. Thus, a good control of the cultural package may result in lower quantities of water used by crops while ensuring good production with a suitable economic profitability. Then, the virtual water

  8. Water balance of field-excavated aestivating Australian desert frogs, the cocoon-forming Neobatrachus aquilonius and the non-cocooning Notaden nichollsi (Amphibia: Myobatrachidae).

    PubMed

    Cartledge, Victoria A; Withers, Philip C; McMaster, Kellie A; Thompson, Graham G; Bradshaw, S Don

    2006-09-01

    Burrowed aestivating frogs of the cocoon-forming species Neobatrachus aquilonius and the non-cocooning species Notaden nichollsi were excavated in the Gibson Desert of central Australia. Their hydration state (osmotic pressure of the plasma and urine) was compared to the moisture content and water potential of the surrounding soil. The non-cocooning N. nichollsi was consistently found in sand dunes. While this sand had favourable water potential properties for buried frogs, the considerable spatial and temporal variation in sand moisture meant that frogs were not always in positive water balance with respect to the surrounding soil. The cocoon-forming N. aquilonius was excavated from two distinct habitat types, a claypan in which frogs had a well-formed cocoon and a dune swale where frogs did not have a cocoon. Cocoons of excavated frogs ranged in thickness from 19.4 microm to 55.61 microm and consisted of 81-229 layers. Cocooned claypan N. aquilonius were nearing exhaustion of their bladder water reserves and had a urine osmolality approaching that of the plasma. By contrast, non-cocooned N. aquilonius from the dune swale were fully hydrated, although soil moisture levels were not as high as calculated to be necessary to maintain water balance. Both species had similar plasma arginine vasotocin (AVT) concentrations ranging from 9.4 to 164 pg ml(-1), except for one cocooned N. aquilonius with a higher concentration of 394 pg ml(-1). For both species, AVT showed no relationship with plasma osmolality over the lower range of plasma osmolalities but was appreciably increased at the highest osmolality recorded. This study provides the first evidence that cocoon formation following burrowing is not obligatory in species that are capable of doing so, but that cocoon formation occurs when soil water conditions are more desiccating than for non-cocooned frogs. PMID:16916967

  9. Soil water sensing for water balance, ET, and WUE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The soil water balance can be solved for evapotranspiration (ET) using data from either weighing lysimetry or soil water sensing and measurement. Weighing lysimeters are expensive and, although accurate, are difficult to manage and afford little replication. Direct soil water measurement by coring i...

  10. Soil water sensing for water balance, ET and WUE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The soil water balance can be solved for evapotranspiration (ET) using data from either weighing lysimetry or soil water sensing and measurement. Weighing lysimeters are expensive and, although accurate, are difficult to manage and afford little replication. Direct soil water measurement by coring i...

  11. Global monthly water stress: 1. Water balance and water availability

    NASA Astrophysics Data System (ADS)

    van Beek, L. P. H.; Wada, Yoshihide; Bierkens, Marc F. P.

    2011-07-01

    Surface fresh water (i.e., blue water) is a vital and indispensable resource for human water use in the agricultural, industrial, and domestic sectors. In this paper, global water availability is calculated by forcing the global hydrological model PCR-GLOBWB with daily global meteorological fields for the period 1958-2001. To represent blue water availability, a prognostic reservoir operation scheme was included in order to produce monthly time series of global river discharge modulated by reservoir operations. To specify green water availability for irrigated areas, actual transpiration from the model was used. Thus, the computed water availability reflects the climatic variability over 1958-2001 and is contrasted against the monthly water demand using the year 2000 as a benchmark in the companion paper. As the water that is withdrawn to meet demand directly interferes with blue water availability along the drainage network, this paper evaluates model performance for three regimes reflecting different degrees of human interference: natural discharge, discharge regulated by reservoirs, and modified discharge. In the case of modified discharge, the net blue water demand for the year 2000 is subtracted directly from the regulated discharge, taking water demand equal to consumptive water use. Results show that model simulations of monthly river discharge compare well with observations from most of the large rivers. Exceptions are basins subject to large extractions for irrigation purposes, where simulated discharge exceeds the observations even when water demand is taken into account. Including the prognostic reservoir operation scheme results in mixed performance, with a poorer approximation of peak flows but with a marginally better simulation of low flows and persistence. A comparison of simulated actual evapotranspiration with that from the ERA-40 reanalysis as a proxy for observed rates shows similar patterns over nonirrigated areas but substantial deviations

  12. International Space Station Water Balance Operations

    NASA Technical Reports Server (NTRS)

    Tobias, Barry; Garr, John D., II; Erne, Meghan

    2011-01-01

    In November 2008, the Water Regenerative System racks were launched aboard Space Shuttle flight, STS-126 (ULF2) and installed and activated on the International Space Station (ISS). These racks, consisting of the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA), completed the installation of the Regenerative (Regen) Environmental Control and Life Support Systems (ECLSS), which includes the Oxygen Generation Assembly (OGA) that was launched 2 years prior. With the onset of active water management on the US segment of the ISS, a new operational concept was required, that of water balance . In November of 2010, the Sabatier system, which converts H2 and CO2 into water and methane, was brought on line. The Regen ECLSS systems accept condensation from the atmosphere, urine from crew, and processes that fluid via various means into potable water, which is used for crew drinking, building up skip-cycle water inventory, and water for electrolysis to produce oxygen. Specification (spec) rates of crew urine output, condensate output, O2 requirements, toilet flush water, and drinking needs are well documented and used as the best guess planning rates when Regen ECLSS came online. Spec rates are useful in long term planning, however, daily or weekly rates are dependent upon a number of variables. The constantly changing rates created a new challenge for the ECLSS flight controllers, who are responsible for operating the ECLSS systems onboard ISS from Mission Control in Houston. This paper reviews the various inputs to water planning, rate changes, and dynamic events, including but not limited to: crew personnel makeup, Regen ECLSS system operability, vehicle traffic, water storage availability, and Carbon Dioxide Removal Assembly (CDRA), Sabatier, and OGA capability. Along with the inputs that change the various rates, the paper will review the different systems, their constraints, and finally the operational challenges and means by which flight controllers

  13. Inter-comparison of four remote sensing based surface energy balance methods to retrieve surface evapotranspiration and water stress of irrigated fields in semi-arid climate

    NASA Astrophysics Data System (ADS)

    Chirouze, J.; Boulet, G.; Jarlan, L.; Fieuzal, R.; Rodriguez, J. C.; Ezzahar, J.; Er-Raki, S.; Bigeard, G.; Merlin, O.; Garatuza-Payan, J.; Watts, C.; Chehbouni, G.

    2013-01-01

    Remotely sensed surface temperature can provide a good proxy for water stress level and is therefore particularly useful to estimate spatially distributed evapotranspiration. Instantaneous stress levels or instantaneous latent heat flux are deduced from the surface energy balance equation constrained by this equilibrium temperature. Pixel average surface temperature depends on two main factors: stress and vegetation fraction cover. Methods estimating stress vary according to the way they treat each factor. Two families of methods can be defined: the contextual methods, where stress levels are scaled on a given image between hot/dry and cool/wet pixels for a particular vegetation cover, and single-pixel methods which evaluate latent heat as the residual of the surface energy balance for one pixel independently from the others. Four models, two contextual (S-SEBI and a triangle method, inspired by Moran et al., 1994) and two single-pixel (TSEB, SEBS) are applied at seasonal scale over a four by four km irrigated agricultural area in semi-arid northern Mexico. Their performances, both at local and spatial standpoints, are compared relatively to energy balance data acquired at seven locations within the area, as well as a more complex soil-vegetation-atmosphere transfer model forced with true irrigation and rainfall data. Stress levels are not always well retrieved by most models, but S-SEBI as well as TSEB, although slightly biased, show good performances. Drop in model performances is observed when vegetation is senescent, mostly due to a poor partitioning both between turbulent fluxes and between the soil/plant components of the latent heat flux and the available energy. As expected, contextual methods perform well when extreme hydric and vegetation conditions are encountered in the same image (therefore, esp. in spring and early summer) while they tend to exaggerate the spread in water status in more homogeneous conditions (esp. in winter).

  14. Intercomparison of four remote-sensing-based energy balance methods to retrieve surface evapotranspiration and water stress of irrigated fields in semi-arid climate

    NASA Astrophysics Data System (ADS)

    Chirouze, J.; Boulet, G.; Jarlan, L.; Fieuzal, R.; Rodriguez, J. C.; Ezzahar, J.; Er-Raki, S.; Bigeard, G.; Merlin, O.; Garatuza-Payan, J.; Watts, C.; Chehbouni, G.

    2014-03-01

    Instantaneous evapotranspiration rates and surface water stress levels can be deduced from remotely sensed surface temperature data through the surface energy budget. Two families of methods can be defined: the contextual methods, where stress levels are scaled on a given image between hot/dry and cool/wet pixels for a particular vegetation cover, and single-pixel methods, which evaluate latent heat as the residual of the surface energy balance for one pixel independently from the others. Four models, two contextual (S-SEBI and a modified triangle method, named VIT) and two single-pixel (TSEB, SEBS) are applied over one growing season (December-May) for a 4 km × 4 km irrigated agricultural area in the semi-arid northern Mexico. Their performance, both at local and spatial standpoints, are compared relatively to energy balance data acquired at seven locations within the area, as well as an uncalibrated soil-vegetation-atmosphere transfer (SVAT) model forced with local in situ data including observed irrigation and rainfall amounts. Stress levels are not always well retrieved by most models, but S-SEBI as well as TSEB, although slightly biased, show good performance. The drop in model performance is observed for all models when vegetation is senescent, mostly due to a poor partitioning both between turbulent fluxes and between the soil/plant components of the latent heat flux and the available energy. As expected, contextual methods perform well when contrasted soil moisture and vegetation conditions are encountered in the same image (therefore, especially in spring and early summer) while they tend to exaggerate the spread in water status in more homogeneous conditions (especially in winter). Surface energy balance models run with available remotely sensed products prove to be nearly as accurate as the uncalibrated SVAT model forced with in situ data.

  15. Regenerative (Regen) ECLSS Operations Water Balance

    NASA Technical Reports Server (NTRS)

    Tobias, Barry

    2010-01-01

    In November 2008, the Water Regenerative System racks were launched aboard Space Shuttle flight, STS-126 (ULF2) and installed and activated on the International Space Station (ISS). These racks, consisting of the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA), completed the installation of the Regenerative (Regen) ECLSS systems which includes the Oxygen Generator Assembly (OGA) that was launched 2 years prior. With the onset of active water management on the US segment of the ISS, a new operational concept was required, that of "water balance." Even more recently, in 2010 the Sabatier system came online which converts H2 and CO2 into water and methane. The Regen ECLSS systems accept condensation from the atmosphere, urine from crew, and processes that fluid via various means into potable water which is used for crew drinking, building up skip-cycle water inventory, and water for electrolysis to produce oxygen. Specification rates of crew urine output, condensate output, O2 requirements, toilet flush water and drinking needs are well documented and used as a general plan when Regen ECLSS came online. Spec rates are useful in long term planning, however, daily or weekly rates are dependent on a number of variables. The constantly changing rates created a new challenge for the ECLSS flight controllers, who are responsible for operating the ECLSS systems onboard ISS. This paper will review the various inputs to rate changes and inputs to planning events, including but not limited to; crew personnel makeup, Regen ECLSS system operability, vehicle traffic, water containment availability, and Carbon Dioxide Removal Assembly (CDRA) capability. Along with the inputs that change the various rates, the paper will review the different systems, their constraints and finally the operational means by which flight controllers manage this new challenge of "water balance."

  16. Balancing Energy-Water-Agriculture Tradeoffs

    NASA Astrophysics Data System (ADS)

    Tidwell, V.; Hightower, M.

    2011-12-01

    In 2005 thermoelectric power production accounted for withdrawals of 201 billion gallons per day (BGD) representing 49% of total withdrawals, making it the largest user of water in the U.S. In terms of freshwater withdrawals thermoelectric power production is the second largest user at 140 BGD just slightly behind freshwater withdrawals for irrigation (USGS 2005). In contrast thermoelectric water consumption is projected at 3.7 BGD or about 3% of total U.S. consumption (NETL 2008). Thermoelectric water consumption is roughly equivalent to that of all other industrial demands and represents one of the fastest growing sectors since 1980. In fact thermoelectric consumption is projected to increase by 42 to 63% between 2005 and 2030 (NETL 2008). Agricultural water consumption has remained relatively constant at roughly 84 BGD or about 84% of total water consumption. While long-term regional electricity transmission planning has traditionally focused on cost, infrastructure utilization, and reliability, issues concerning the availability of water represent an emerging issue. Thermoelectric expansion must be considered in the context of competing demands from other water use sectors balanced with fresh and non-fresh water supplies subject to climate variability. Often such expansion targets water rights transfers from irrigated agriculture. To explore evolving tradeoffs an integrated energy-water-agriculture decision support system has been developed. The tool considers alternative expansion scenarios for the future power plant fleet and the related demand for water. The availability of fresh and non-fresh water supplies, subject to local institutional controls is then explored. This paper addresses integrated energy-water-agriculture planning in the western U.S. and Canada involving an open and participatory process comprising decision-makers, regulators, utility and water managers.

  17. Water Balance Covers For Waste Containment: Principles and Practice

    EPA Science Inventory

    Water Balance Covers for Waste Containment: Principles and Practices introduces water balance covers and compares them with conventional approaches to waste containment. The authors provided detailed analysis of the fundamentals of soil physics and design issues, introduce appl...

  18. Concepts to accelerate water balance model computation

    NASA Astrophysics Data System (ADS)

    Gronz, Oliver; Casper, Markus; Gemmar, Peter

    2010-05-01

    Computation time of water balance models has decreased with the increasing performance of CPUs within the last decades. Often, these advantages have been used to enhance the models, e. g. by enlarging spatial resolution or by using smaller simulation time steps. During the last few years, CPU development tended to focus on strong multi core concepts rather than 'simply being generally faster'. Additionally, computer clusters or even computer clouds have become much more commonly available. All these facts again extend our degrees of freedom in simulating water balance models - if the models are able to efficiently use the computer infrastructure. In the following, we present concepts to optimize especially repeated runs and we generally discuss concepts of parallel computing opportunities. Surveyed model In our examinations, we focused on the water balance model LARSIM. In this model, the catchment is subdivided into elements, each of which representing a certain section of a river and its contributory area. Each element is again subdivided into single compartments of homogeneous land use. During the simulation, the relevant hydrological processes are simulated individually for each compartment. The simulated runoff of all compartments leads into the river channel of the corresponding element. Finally, channel routing is simulated for all elements. Optimizing repeated runs During a typical simulation, several input files have to be read before simulation starts: the model structure, the initial model state and meteorological input files. Furthermore, some calculations have to be solved, like interpolating meteorological values. Thus, e. g. the application of Monte Carlo methods will typically use the following algorithm: 1) choose parameters, 2) set parameters in control files, 3) run model, 4) save result, 5) repeat from step 1. Obviously, the third step always includes the previously mentioned steps of reading and preprocessing. Consequently, the model can be

  19. Trends in water balance components across the Brazilian Cerrado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Brazilian Cerrado (Savanna) is considered one of the most important biomes for Brazilian water resources; however, little is known about the components of the water balance in this biome. In this study, we reviewed the available literature on the water balance components in the Brazilian Cerrado...

  20. Sensible heat balance measurements of soil water evaporation beneath a maize canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water evaporation is an important component of the water budget in a cropped field. Few methods are available for continuous and independent measurement of soil water evaporation. A sensible heat balance (SHB) approach has recently been demonstrated for continuously determining soil water evapo...

  1. Evaporative cooling and water balance during flight in birds.

    PubMed

    Torre-Bueno, J R

    1978-08-01

    The rate of evaporative cooling was calculated from the rate of mass loss in starlings (Sturnus vulgaris) during 90 min flights in a wind-tunnel. Evaporative heat loss ranged from 5% of the metabolic rate at -5 degrees C to 19% of the metabolic rate at 29 degrees C. Radiation and convection accounted for the balance of the heat loss. On average, starlings dehydrated during flights at all temperatures above 7 degrees C. The comparison of these results with data from field studies, which indicate that long-distance migrants do not dehydrate, suggests that migrants may maintain water balance by ascending to colder air in which convection carries off most of the heat produced. PMID:702042

  2. Concepts to accelerate water balance model computation

    NASA Astrophysics Data System (ADS)

    Gronz, Oliver; Casper, Markus; Gemmar, Peter

    2010-05-01

    Computation time of water balance models has decreased with the increasing performance of CPUs within the last decades. Often, these advantages have been used to enhance the models, e. g. by enlarging spatial resolution or by using smaller simulation time steps. During the last few years, CPU development tended to focus on strong multi core concepts rather than 'simply being generally faster'. Additionally, computer clusters or even computer clouds have become much more commonly available. All these facts again extend our degrees of freedom in simulating water balance models - if the models are able to efficiently use the computer infrastructure. In the following, we present concepts to optimize especially repeated runs and we generally discuss concepts of parallel computing opportunities. Surveyed model In our examinations, we focused on the water balance model LARSIM. In this model, the catchment is subdivided into elements, each of which representing a certain section of a river and its contributory area. Each element is again subdivided into single compartments of homogeneous land use. During the simulation, the relevant hydrological processes are simulated individually for each compartment. The simulated runoff of all compartments leads into the river channel of the corresponding element. Finally, channel routing is simulated for all elements. Optimizing repeated runs During a typical simulation, several input files have to be read before simulation starts: the model structure, the initial model state and meteorological input files. Furthermore, some calculations have to be solved, like interpolating meteorological values. Thus, e. g. the application of Monte Carlo methods will typically use the following algorithm: 1) choose parameters, 2) set parameters in control files, 3) run model, 4) save result, 5) repeat from step 1. Obviously, the third step always includes the previously mentioned steps of reading and preprocessing. Consequently, the model can be

  3. Biodiversity effects on the water balance of an experimental grassland

    NASA Astrophysics Data System (ADS)

    Leimer, Sophia; Kreutziger, Yvonne; Rosenkranz, Stephan; Beßler, Holger; Engels, Christof; Oelmann, Yvonne; Weisser, Wolfgang W.; Wirth, Christian; Wilcke, Wolfgang

    2013-04-01

    Plant species richness increases aboveground biomass production in biodiversity experiments. Biomass production depends on and feeds back to the water balance, but it remains unclear how plant species richness influences soil water contents and water fluxes (actual evapotranspiration (ETa), downward flux (DF), and upward flux (UF)). Our objective was to determine the effects of plant species and functional richness and functional identity on soil water contents and water fluxes for two soil depths (0-0.3 and 0.3.-0.7 m). To achieve this, we used a water balance model in connection with Bayesian hierarchical modeling. We monitored soil water contents on 86 plots of a grassland plant diversity experiment in Jena, Germany between July 2002 and January 2006. In the field experiment, plant species richness (0, 1, 2, 4, 8, 16, 60) and functional group composition (0-4 functional groups: legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs) were manipulated in a factorial design. Climate data (air temperature, precipitation, wind velocity, relative humidity, global radiation, soil moisture) was measured at a central climate station between July 2002 and December 2007. Root biomass data from July 2006 was available per plot. Missing water contents per plot and depth were estimated in weekly resolution for the years 2003-2007 with a Bayesian hierarchical model using measured water contents per plot and centrally measured soil moisture. To obtain ETa, DF, and UF of the two different soil depths, we modified a soil water balance model which had been developed for our study site. The model is based on changes in soil water content between subsequent observation dates and modeled potential evapotranspiration which was partitioned between soil layers according to percentage of root biomass. The presence of specific functional groups significantly changed water contents and fluxes with partly opposing effects in the two soil depths. Presence of grasses

  4. Assessment of availability water at Boi Branco watershed through the water climate balance and growing

    NASA Astrophysics Data System (ADS)

    Alexandre de Lima Sales, Mariana; Máximo Sanchez-Román, Rodrigo; Rodríguez-Sinobas, Leonor; Ribeiro da Silva de Souza, Joao Victor; Nonato Farias Monteiro, Raimundo

    2015-04-01

    The water resources are fundamental to the development of several economic activities. Concerning the agriculture production, the water can represent close to 90% of the physical constitution of the plant. The low water supply during the growing stage of vegetables can make the agricultural production not viable and can even seriously affect the balance of the ecosystem. One way to calculate the amount of water in a determined system is by means of the water balance, that is an important tool for the assessment process of the water cycle in a specific region. The main goal of this work was to establish the water balance in the watershed Boi Branco-SP, so that it can be used as a tool for the hydro-agricultural and environmental planning of the region. For the water climate balance, it was used data of the historical series of the region (1971 - 1995). The data of evapotranspiration were estimated by the method Thornthwaite. The water climate balance showed low water supply total annual of 10.1 mm, and exceeding of 319.7 mm, wherein in month January an exceeding of 92.6 to the average monthly precipitation; given the effective monthly precipitation with probability of 75% low water supply in the soil it is 238.8 mm and the exceeding 56.8 mm. When these data are added to the ones of the crop, as a crop coefficient and availability factor of water in the soil, it is observed that all crops which are inserted in the watershed present low water supply in all the months they are in the field. As the water balance is an important assessment of a specific region, further studies are recommended, with data collected in the region, so that the update in the results is obtained. Thus, it is also recommended the establishment of a system for agrometerological collecting data to help the irrigation management and other agricultural activities. Keyword: Water agricultural planning, water capability available in the soil, evapotranspiration.

  5. Characteristics of water and carbon balance in moso bamboo forests

    NASA Astrophysics Data System (ADS)

    Kume, T.; Laplace, S.; Tseng, H.; Hsieh, Y.; Wey, T.; Komatsu, H.

    2013-12-01

    Water and carbon cycles in mountainous areas can have considerable impacts on our available nature resources such as water resources and timber production. Thus, it is indispensable to clarify the difference of water and carbon balances between different types of forested ecosystems. Recently, bamboo forests have been expanding by replacing surrounding vegetation such as coniferous and broad-leaved forests in eastern Asian countries. It has been speculated that the replacements by bamboo forests could alter the vegetation water and carbon cycles. However, our knowledge for the bamboo forests was still limited due to lack of applicable methodology based on a field measurement. To clarify the potential impacts of bamboo expansion on water and carbon cycles, our previous study established optimal and effective design for assessing bamboo forest water use (ie, transpiration) based on sap flux measurements. Using the method, we quantified stand-scale transpiration in bamboo forests and coniferous forests in Taiwan. Consequently, we found significantly larger transpiration in bamboo forests compared with those of surrounding vegetation due to larger canopy conductance in bamboo forests. The unique characteristics of the water use accompanied larger carbon assimilation and soil CO2 efflux in bamboo forests.

  6. Management of the water balance and quality in mining areas

    NASA Astrophysics Data System (ADS)

    Pasanen, Antti; Krogerus, Kirsti; Mroueh, Ulla-Maija; Turunen, Kaisa; Backnäs, Soile; Vento, Tiia; Veijalainen, Noora; Hentinen, Kimmo; Korkealaakso, Juhani

    2015-04-01

    Although mining companies have long been conscious of water related risks they still face environmental management problems. These problems mainly emerge because mine sites' water balances have not been adequately assessed in the stage of the planning of mines. More consistent approach is required to help mining companies identify risks and opportunities related to the management of water resources in all stages of mining. This approach requires that the water cycle of a mine site is interconnected with the general hydrologic water cycle. In addition to knowledge on hydrological conditions, the control of the water balance in the mining processes require knowledge of mining processes, the ability to adjust process parameters to variable hydrological conditions, adaptation of suitable water management tools and systems, systematic monitoring of amounts and quality of water, adequate capacity in water management infrastructure to handle the variable water flows, best practices to assess the dispersion, mixing and dilution of mine water and pollutant loading to receiving water bodies, and dewatering and separation of water from tailing and precipitates. WaterSmart project aims to improve the awareness of actual quantities of water, and water balances in mine areas to improve the forecasting and the management of the water volumes. The study is executed through hydrogeological and hydrological surveys and online monitoring procedures. One of the aims is to exploit on-line water quantity and quality monitoring for the better management of the water balances. The target is to develop a practical and end-user-specific on-line input and output procedures. The second objective is to develop mathematical models to calculate combined water balances including the surface, ground and process waters. WSFS, the Hydrological Modeling and Forecasting System of SYKE is being modified for mining areas. New modelling tools are developed on spreadsheet and system dynamics platforms to

  7. Hydro-Balanced Stuffing Box field test

    SciTech Connect

    Giangiacomo, L.A.

    1999-05-28

    The Hydro-Balanced Stuffing Box is a seal assembly for polished rod pumping installations commonly used in oil and gas pumping well installations to contain produced well fluids. The improved stuffing box was developed and patented by Harold H. Palmour of The Palmour Group of Livingston, TX. The stuffing box is designed to reduce the incidence of seal leakage and to utilize an environmentally safe fluid, so that if there is any leakage, environmental damage is reduced or eliminated. The unit was tested on two wells at the Rocky Mountain Oilfield Testing Center. During the test period, the performance of the stuffing box was measured by monitoring the pressure on the tubing and the inner chamber with a Barton Two-pen recorder. The amount of safe fluid consumed, fluid leakage at the top of the stuffing box, pressure supplied from the nitrogen bottle, ambient temperature, and polish rod temperature was recorded. The stuffing box is capable of providing a better seal between well fluids an d the environment than conventional stuffing boxes. It allows the polished rod to operate cooler and with lubrication, extending the life of the packing elements, and reducing the amount of attention required to prevent leakage.

  8. Acid-based balance and blood gas changes in the fresh water field crab, Barytelphusa guerini, on exposure to organic and inorganic lead

    SciTech Connect

    Tulasi, S.J.; Rao, J.V.R.

    1988-02-01

    The acid-base status of crustacean haemolymph depends on various environmental and physiological factors. Acid base status of the haemolymph is known to be influenced by temperature, salinity, strenuous activity and moulting. The studies on the acid-base regulation of the fresh water crabs are meager. The acid-base changes in fishes during environmental stress conditions like acid stress and zinc toxicity had been reported. But the effect of environmental pollutants like the heavy metals on the acid-base regulation of the fresh water crabs have not been previously reported. The haemolymph of the fresh water crab was found to accumulate high amounts of lead on exposure to organic and inorganic lead. Hence the present investigation has been undertaken to study the haemolymph acid-base status on exposure to subtoxic levels of organic and inorganic lead.

  9. Comparison of Dynamic Balance in Collegiate Field Hockey and Football Players Using Star Excursion Balance Test

    PubMed Central

    Bhat, Rashi; Moiz, Jamal Ali

    2013-01-01

    Purpose The preliminary study aimed to compare dynamic balance between collegiate athletes competing or training in football and hockey using star excursion balance test. Methods A total thirty university level players, football (n = 15) and field hockey (n = 15) were participated in the study. Dynamic balance was assessed by using star excursion balance test. The testing grid consists of 8 lines each 120 cm in length extending from a common point at 45° increments. The subjects were instructed to maintain a stable single leg stance with the test leg with shoes off and to reach for maximal distance with the other leg in each of the 8 directions. A pencil was used to point and read the distance to which each subject's foot reached. The normalized leg reach distances in each direction were summed for both limbs and the total sum of the mean of summed normalized distances of both limbs were calculated. Results There was no significant difference in all the directions of star excursion balance test scores in both the groups. Additionally, composite reach distances of both groups also found non-significant (P=0.5). However, the posterior (P=0.05) and lateral (P=0.03) normalized reach distances were significantly more in field hockey players. Conclusion Field hockey players and football players did not differ in terms of dynamic balance. PMID:24427482

  10. Assessment of Cropland Water and Nitrogen Balance from Climate Change in Korea Peninsular

    NASA Astrophysics Data System (ADS)

    Lim, C. H.; Song, C.; Kim, T.; Lee, W. K.; Jeon, S. W.

    2015-12-01

    If crop growth is based on cropland productivity, the changes are due to changes in water and nitrogen balance from climate. In this study, order to estimation the change in cropland water and nitrogen balance in Korea peninsular using meteorological data observed last 30 years(1984-2013y). And we used soil, topography and management data about cropland. So as to estimating water and nitrogen variables, we used to the GIS based EPIC model that is major crop model in agro-ecosystem modelling field. Among the much of water and nitrogen variables, we selected to evapotranspiration, runoff, precipitation, nitrification, N lost, N contents and denitrification for this analysis. This selected variables associate with cropland water and nitrogen balance.First result, we can found the water balance changes in Korea peninsular, especially South Korea better condition than North Korea. In North Korea, evapotranspiration and precipitation result were lower than South Korea, but runoff result was bigger than South Korea. And we got a result about nitrogen balance changes in Korea peninsular from climate. In spatially, South and North Korea showed to similar condition on nitrogen balance in whole period. But in temporally, showed negative trends as time goes on, it caused by climate change. Overall condition of water and nitrogen balance on last 30 years in Korea peninsular, South Korea showed better condition than North Korea. Water and nitrogen balance change means have to be changed on agriculture management action, such as irrigation and fertilizer. In future period, climate change will cause a large effect to cropland water and nitrogen balance in mid-latitude area, so we have to prepare the change of this field for wise adaptation by climate change.

  11. Fuzzy-probabilistic calculations of water-balance uncertainty

    SciTech Connect

    Faybishenko, B.

    2009-10-01

    Hydrogeological systems are often characterized by imprecise, vague, inconsistent, incomplete, or subjective information, which may limit the application of conventional stochastic methods in predicting hydrogeologic conditions and associated uncertainty. Instead, redictions and uncertainty analysis can be made using uncertain input parameters expressed as probability boxes, intervals, and fuzzy numbers. The objective of this paper is to present the theory for, and a case study as an application of, the fuzzyprobabilistic approach, ombining probability and possibility theory for simulating soil water balance and assessing associated uncertainty in the components of a simple waterbalance equation. The application of this approach is demonstrated using calculations with the RAMAS Risk Calc code, to ssess the propagation of uncertainty in calculating potential evapotranspiration, actual evapotranspiration, and infiltration-in a case study at the Hanford site, Washington, USA. Propagation of uncertainty into the results of water-balance calculations was evaluated by hanging he types of models of uncertainty incorporated into various input parameters. The results of these fuzzy-probabilistic calculations are compared to the conventional Monte Carlo simulation approach and estimates from field observations at the Hanford site.

  12. Evaluation of a distributed catchment scale water balance model

    NASA Technical Reports Server (NTRS)

    Troch, Peter A.; Mancini, Marco; Paniconi, Claudio; Wood, Eric F.

    1993-01-01

    The validity of some of the simplifying assumptions in a conceptual water balance model is investigated by comparing simulation results from the conceptual model with simulation results from a three-dimensional physically based numerical model and with field observations. We examine, in particular, assumptions and simplifications related to water table dynamics, vertical soil moisture and pressure head distributions, and subsurface flow contributions to stream discharge. The conceptual model relies on a topographic index to predict saturation excess runoff and on Philip's infiltration equation to predict infiltration excess runoff. The numerical model solves the three-dimensional Richards equation describing flow in variably saturated porous media, and handles seepage face boundaries, infiltration excess and saturation excess runoff production, and soil driven and atmosphere driven surface fluxes. The study catchments (a 7.2 sq km catchment and a 0.64 sq km subcatchment) are located in the North Appalachian ridge and valley region of eastern Pennsylvania. Hydrologic data collected during the MACHYDRO 90 field experiment are used to calibrate the models and to evaluate simulation results. It is found that water table dynamics as predicted by the conceptual model are close to the observations in a shallow water well and therefore, that a linear relationship between a topographic index and the local water table depth is found to be a reasonable assumption for catchment scale modeling. However, the hydraulic equilibrium assumption is not valid for the upper 100 cm layer of the unsaturated zone and a conceptual model that incorporates a root zone is suggested. Furthermore, theoretical subsurface flow characteristics from the conceptual model are found to be different from field observations, numerical simulation results, and theoretical baseflow recession characteristics based on Boussinesq's groundwater equation.

  13. Regulation of water balance in mangroves

    PubMed Central

    Reef, Ruth; Lovelock, Catherine E.

    2015-01-01

    Background Mangroves are a group of highly salt-tolerant woody plants. The high water use efficiency of mangroves under saline conditions suggests that regulation of water transport is a crucial component of their salinity tolerance. Scope This review focuses on the processes that contribute to the ability of mangroves to maintain water uptake and limit water loss to the soil and the atmosphere under saline conditions, from micro to macro scales. These processes include: (1) efficient filtering of the incoming water to exclude salt; (2) maintenance of internal osmotic potentials lower than that of the rhizosphere; (3) water-saving properties; and (4) efficient exploitation of less-saline water sources when these become available. Conclusions Mangroves are inherently plastic and can change their structure at the root, leaf and stand levels in response to salinity in order to exclude salt from the xylem stream, maintain leaf hydraulic conductance, avoid cavitation and regulate water loss (e.g. suberization of roots and alterations of leaf size, succulence and angle, hydraulic anatomy and biomass partitioning). However, much is still unknown about the regulation of water uptake in mangroves, such as how they sense and respond to heterogeneity in root zone salinity, the extent to which they utilize non-stomatally derived CO2 as a water-saving measure and whether they can exploit atmospheric water sources. PMID:25157072

  14. A catchment scale water balance model for FIFE

    NASA Technical Reports Server (NTRS)

    Famiglietti, J. S.; Wood, E. F.; Sivapalan, M.; Thongs, D. J.

    1992-01-01

    A catchment scale water balance model is presented and used to predict evaporation from the King's Creek catchment at the First ISLSCP Field Experiment site on the Konza Prairie, Kansas. The model incorporates spatial variability in topography, soils, and precipitation to compute the land surface hydrologic fluxes. A network of 20 rain gages was employed to measure rainfall across the catchment in the summer of 1987. These data were spatially interpolated and used to drive the model during storm periods. During interstorm periods the model was driven by the estimated potential evaporation, which was calculated using net radiation data collected at site 2. Model-computed evaporation is compared to that observed, both at site 2 (grid location 1916-BRS) and the catchment scale, for the simulation period from June 1 to October 9, 1987.

  15. Development of a 5-Component Balance for Water Tunnel Applications

    NASA Technical Reports Server (NTRS)

    Suarez, Carlos J.; Kramer, Brian R.; Smith, Brooke C.

    1999-01-01

    The principal objective of this research/development effort was to develop a multi-component strain gage balance to measure both static and dynamic forces and moments on models tested in flow visualization water tunnels. A balance was designed that allows measuring normal and side forces, and pitching, yawing and rolling moments (no axial force). The balance mounts internally in the model and is used in a manner typical of wind tunnel balances. The key differences between a water tunnel balance and a wind tunnel balance are the requirement for very high sensitivity since the loads are very low (typical normal force is 90 grams or 0.2 lbs), the need for water proofing the gage elements, and the small size required to fit into typical water tunnel models. The five-component balance was calibrated and demonstrated linearity in the responses of the primary components to applied loads, very low interactions between the sections and no hysteresis. Static experiments were conducted in the Eidetics water tunnel with delta wings and F/A-18 models. The data were compared to forces and moments from wind tunnel tests of the same or similar configurations. The comparison showed very good agreement, providing confidence that loads can be measured accurately in the water tunnel with a relatively simple multi-component internal balance. The success of the static experiments encouraged the use of the balance for dynamic experiments. Among the advantages of conducting dynamic tests in a water tunnel are less demanding motion and data acquisition rates than in a wind tunnel test (because of the low-speed flow) and the capability of performing flow visualization and force/moment (F/M) measurements simultaneously with relative simplicity. This capability of simultaneous flow visualization and for F/M measurements proved extremely useful to explain the results obtained during these dynamic tests. In general, the development of this balance should encourage the use of water tunnels for a

  16. The Hydration Equation: Update on Water Balance and Cognitive Performance

    PubMed Central

    Riebl, Shaun K; Davy, Brenda M.

    2013-01-01

    LEARNING OBJECTIVES To become aware of the most practical measures of hydration status.To describe sources of water input and output and the basics of water balance.To understand how hydration status may impact daily cognitive performance. CONDENSED VERSION AND BOTTOM LINE Water is a crucial nutrient and euhydration is necessary for optimal daily functioning. Water balance is precisely regulated within the body and many methods exist for assessing hydration status. Cognitive performance measures an individual’s attentiveness, critical thinking skills, and memory. Traditionally a 2% or more body water deficit was thought to produce cognitive performance decrements; however, recent literature suggests that even mild dehydration – a body water loss of 1–2% – can impair cognitive performance. Counseling clients about their health and wellbeing should include conveying the importance of water for normal body functioning, as well as its effects on physical and cognitive performance. PMID:25346594

  17. Development of a simplified urban water balance model (WABILA).

    PubMed

    Henrichs, M; Langner, J; Uhl, M

    2016-01-01

    During the last decade, water sensitive urban design (WSUD) has become more and more accepted. However, there is not any simple tool or option available to evaluate the influence of these measures on the local water balance. To counteract the impact of new settlements, planners focus on mitigating increases in runoff through installation of infiltration systems. This leads to an increasing non-natural groundwater recharge and decreased evapotranspiration. Simple software tools which evaluate or simulate the effect of WSUD on the local water balance are still needed. The authors developed a tool named WABILA (Wasserbilanz) that could support planners for optimal WSUD. WABILA is an easy-to-use planning tool that is based on simplified regression functions for established measures and land covers. Results show that WSUD has to be site-specific, based on climate conditions and the natural water balance. PMID:27120631

  18. Assessment of balance among adolescent track and field athletes.

    PubMed

    Knight, Adam C; Holmes, Megan E; Chander, Harish; Kimble, Amari; Stewart, Joshua Ty

    2016-06-01

    Track and field events place different demands on athletes and may have an effect on balance. This study investigated the effects of event specialty, gender, and leg dominance on balance among adolescent track and field athletes. Forty healthy adolescent track and field athletes (male = 23, female = 17) categorised into three different groups (sprinter = 20, distance runners = 13, throwers = 7) had their single leg static balance measured with the eyes open and the eyes closed using an AMTI force platform. Dependent variables included average displacement (cm) of the centre of pressure (COP) in the anterior/posterior direction and medial/lateral directions, the average velocity of the COP (cm/s) and the 95% ellipse area (cm(2)). Variables were analysed using a 3 (event specialty) × 2 (gender) × 2 (leg) ANOVA with repeated measures on the leg variable (p < 0.05). There was a significant difference (p < 0.05) in the average displacement of the COP in the medial/lateral direction for both the eyes open and closed condition, with the non-dominant leg demonstrating greater displacement than the dominant leg. This might increase the risk of injury for the non-dominant leg, but additional data should be collected and analysed on both dynamic balance and performance. PMID:27111401

  19. A GIS water balance approach to support surface water flood risk management

    NASA Astrophysics Data System (ADS)

    Diaz-Nieto, J.

    Concern has arisen as to whether the lack of appropriate consideration to surface water in urban spatial planning is reducing our capacity to manage surface water flood risk. Appropriate tools are required that allow spatial planners to explore opportunities and solutions for surface after flooding at large spatial scales. An urban surface water balance model has been developed that screens large urban areas to identify flooded areas and which allows solutions to be explored. The model hypothesis is that key hydrological characteristics; storage volume and location, flow paths and surface water generation capture the key processes responsible for surface water flooding> The model uses a LiDAR DEM (Light Detection and Ranging Digital Elevation Model) as the basis for determining surface water accumulation in a catchment and has been developed so that it requires minimal inputs and computational resources. The urban surface water balance approach is applied to Keighley in West Yorkshire where several instances of surface water flooding have been reported. This research used a postal questionnaire, followed up with site visits to collect data on surface water flooding locations in Keighley. A qualitative analysis based on field visits revealed that the degree of interaction with the sewer network varies spatially, and as the importance of the interaction of the sewer system increase, the accuracy of the model results are lowered. It also highlighted that local detail not present in the DEM, the presence of urban drainage assets and the performance of the sewer system which are not be represented in the model, can determine the accuracy of model results. Model results were used as a basis to develop solutions to surface water flooding. A least cost path methodology was developed to identify managed flood routes as a solution. These were translated into model inputs in the form a modified DEM.

  20. Mean surface water balance over Africa and its interannual variability

    SciTech Connect

    Nicholson, S.E.; Kim, J.; Ba, M.B.; Lare, A.R.

    1997-12-01

    This article presents calculations of surface water balance for the African continent using a revised version of the Lettau climatonomy. Calculations are based on approximately 1400 rainfall stations, with records generally covering 60 yr or longer. Continental maps of evapotranspiration. runoff, and soil moisture are derived for January, July, and the annual mean. The model is also used to provide a gross estimate of the interannual variability of these parameters over most of the continent and local water balance calculations for a variety of locations in Africa. The results are compared with four other comprehensive global water balance studies. The results of this study are being used to produce a gridded dataset for the continent, with potential applications for numerical modeling studies. 50 refs., 18 figs., 3 tabs.

  1. Water balance approach to determine upward water movement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shallow water tables can contribute water moving up into the root zone. The purpose of this study was to quantify upward moving water. Automated sensors were used to monitor soil water content and water table depth on sites in Central Iowa, which had varying shallow water tables. Tipping bucket rain...

  2. Water balance of rice plots under three different water treatments: monitoring activity and experimental results

    NASA Astrophysics Data System (ADS)

    Chiaradia, Enrico Antonio; Romani, Marco; Facchi, Arianna; Gharsallah, Olfa; Cesari de Maria, Sandra; Ferrari, Daniele; Masseroni, Daniele; Rienzner, Michele; Battista Bischetti, Gian; Gandolfi, Claudio

    2014-05-01

    In the agricultural seasons 2012 and 2013, a broad monitoring activity was carried out at the Rice Research Centre of Ente Nazionale Risi (CRR-ENR) located in Castello d'Agogna (PV, Italy) with the purpose of comparing the water balance components of paddy rice (Gladio cv.) under different water regimes and assessing the possibility of reducing the high water inputs related to the conventional practice of continuous submergence. The experiments were laid out in six plots of about 20 m x 80 m each, with two replicates for each of the following water regimes: i) continuous flooding with wet-seeded rice (FLD), ii) continuous flooding from around the 3-leaf stage with dry-seeded rice (3L-FLD), and iii) surface irrigation every 7-10 days with dry-seeded rice (IRR). One out of the two replicates of each treatment was instrumented with: water inflow and outflow meters, set of piezometers, set of tensiometers and multi-sensor moisture probes. Moreover, an eddy covariance station was installed on the bund between the treatments FLD and IRR. Data were automatically recorded and sent by a wireless connection to a PC, so as to be remotely controlled thanks to the development of a Java interface. Furthermore, periodic measurements of crop biometric parameters (LAI, crop height and rooting depth) were performed in both 2012 and 2013 (11 and 14 campaigns respectively). Cumulative water balance components from dry-seeding (3L-FLD and IRR), or flooding (FLD), to harvest were calculated for each plot by either measurements (i.e. rainfall, irrigation and surface drainage) or estimations (i.e. difference in the field water storage, evaporation from both the soil and the water surface and transpiration), whereas the sum of percolation and capillary rise (i.e. the 'net percolation') was obtained as the residual term of the water balance. Incidentally, indices of water application efficiency (evapotranspiration over net water input) and water productivity (grain production over net water

  3. Virtual water flows and Water Balance Impacts of the U.S. Great Lakes Basin

    NASA Astrophysics Data System (ADS)

    Ruddell, B. L.; Mayer, A. S.; Mubako, S. T.

    2014-12-01

    To assess the impacts of human water use and trade on water balances, we estimate virtual water flows for counties in the U.S. portion of the Great Lakes basin. This is a water-rich region, but one where ecohydrological 'hotspots' are created by water scarcity in certain locations (Mubako et al., 2012). Trade shifts water uses from one location to another, causing water scarcity in some locations but mitigating water scarcity in other locations. A database of water withdrawals was assembled to give point-wise withdrawals by location, source, and use category (commercial, thermoelectric power, industrial, agricultural, mining). Point-wise consumptive use is aggregated to the county level, giving direct, virtual water exports by county. A county-level trade database provides import and export data for the various use categories. We link the annual virtual water exported from a county for a given use category to corresponding annual trade exports. Virtual water balances for each county by use category are calculated, and then compared with the renewable annual freshwater supply. Preliminary findings are that overall virtual water balances (imports - exports) are positive for almost all counties, because urban areas import goods and services that are more water intensive than the exported goods and services. However, for some agriculturally-intensive counties, the overall impact of virtual water trade on the water balance is close to zero, and the balance for agricultural sector virtual water trade is negative, reflecting a net impact of economic trade on the water balance in these locations. We also compare the virtual water balance to available water resources, using annual precipitation less evapotranspiration as a crude estimate of net renewable water availability. In some counties virtual water exports approach 30% of the available water resources, indicating the potential for water scarcity, especially from an aquatic ecosystem standpoint.

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

    NASA Astrophysics Data System (ADS)

    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-balance

  5. Seasonal Water Balance Forecasts for Drought Early Warning in Ethiopia

    NASA Astrophysics Data System (ADS)

    Spirig, Christoph; Bhend, Jonas; Liniger, Mark

    2016-04-01

    Droughts severely impact Ethiopian agricultural production. Successful early warning for drought conditions in the upcoming harvest season therefore contributes to better managing food shortages arising from adverse climatic conditions. So far, however, meteorological seasonal forecasts have not been used in Ethiopia's national food security early warning system (i.e. the LEAP platform). Here we analyse the forecast quality of seasonal forecasts of total rainfall and of the meteorological water balance as a proxy for plant available water. We analyse forecast skill of June to September rainfall and water balance from dynamical seasonal forecast systems, the ECMWF System4 and EC-EARTH global forecasting systems. Rainfall forecasts outperform forecasts assuming a stationary climate mainly in north-eastern Ethiopia - an area that is particularly vulnerable to droughts. Forecasts of the water balance index seem to be even more skilful and thus more useful than pure rainfall forecasts. The results vary though for different lead times and skill measures employed. We further explore the potential added value of dynamically downscaling the forecasts through several dynamical regional climate models made available through the EU FP7 project EUPORIAS. Preliminary results suggest that dynamically downscaled seasonal forecasts are not significantly better compared with seasonal forecasts from the global models. We conclude that seasonal forecasts of a simple climate index such as the water balance have the potential to benefit drought early warning in Ethiopia, both due to its positive predictive skill and higher usefulness than seasonal mean quantities.

  6. The climatic water balance in an ecological context

    NASA Astrophysics Data System (ADS)

    Stephenson, N. L.

    2011-12-01

    Because the climatic water balance describes the seasonal interactions of energy (heat and solar radiation) and water in biologically meaningful ways, it provides a powerful tool for understanding and predicting the effects of climatic changes on the terrestrial biosphere. I begin with a brief overview of the definitions and interpretations of the biologically most important water balance parameters -- actual evapotranspiration (AET) and climatic water deficit (Deficit) -- and how the particular approach used to calculate these parameters depends both on the goals of the study and on the available climatic data. Some authors have attempted to represent aspects of the climatic water balance with indices based on annual potential evapotranspiration (PET) and precipitation (P), such at P/PET or PET - P. However, these and related indices do not reflect soil water dynamics, snow dynamics, or the seasonal interactions of energy and water, and therefore have no biological interpretation. Consequently, such indices are more poorly correlated with ecological patterns and processes than AET and Deficit. Of critical importance, the effects of changing energy and water supplies on the climatic water balance are nearly orthogonal. For example, a plant community growing on shallow soils on a shaded slope and one growing on deep soils on a sunward slope often may have the same amount of measured soil moisture available to them. However, the dynamics of energy and water that resulted in the identical soil moistures were fundamentally different (decreased evaporative demand on the shaded slope versus increased water supply on the deep soils); the associated differences in AET and Deficit will therefore result in different plant communities occupying the sites, in spite of identical soil moistures. In the context of climatic change, the orthogonal effects of energy and water mean that increasing precipitation cannot be expected to counteract the effects of increasing temperature

  7. Remotely Sensed Terrestrial Water Balance of the Nile Basin

    NASA Astrophysics Data System (ADS)

    Smith, T. T.; Zaitchik, B. F.; Anderson, M. C.; Yilmaz, M. T.; Alo, C. A.; Rodell, M.

    2011-12-01

    Satellite-derived estimates of precipitation, evapotranspiration (ET), and water storage have transformed our understanding of hydrological dynamics at the basin scale. At the same time, the profusion of satellite and model-generated hydrological estimates has demonstrated that there is still considerable uncertainty associated with the quantification of hydrologic states and fluxes at basin scale: the use of different combinations of data products can lead to dramatically different conclusions regarding water balance partitioning as well as variability and trends in water storage. Including multiple independent products in studies of basin-scale hydrology makes it possible to evaluate known uncertainties in satellite estimates of each component of the hydrological cycle, to assess the influence of these uncertainties on our ability to address hydrological questions of interest, and to identify critical data needs for future satellite missions. Here we present results of a basin-scale water balance analyses of the Nile River basin over the time period of 2007-2010. Multiple satellite-derived and model-based precipitation, ET, and terrestrial water storage products are included in order to characterize absolute and relative uncertainties for each variable of the terrestrial water balance equation. Monthly runoff values are estimated as the residual of the basin water balance. These runoff values are then compared with historical river gauge data to assess the utility of each data combination for estimating river flow and flow variability. Tested products include: the Tropical Rainfall Measurement Mission (TRMM) Multisensor Precipitation Analysis and Climate Prediction Center operational Africa Rainfall Estimates (RFE 2) for precipitation; the Atmospheric-Land Exchange Inverse (ALEXI) model and offline Land Surface Models (LSMs) for ET; and Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage anomaly, merged thermal and microwave derived soil

  8. The water balance estimation for catastrophic floods: groundwater contribution

    NASA Astrophysics Data System (ADS)

    Arakelian, Sergey; Vinogradov, Alexey; Tulenev, Nikita; Trifonova, Tatiana

    2016-04-01

    1. We discuss the existing problems in the study of the mechanisms of formation of catastrophic floods taking into account the possible influence of groundwater. The difficulty in assessing the causes of the disastrous floods is linked to the lack of direct field measurements of precipitation and so, to estimate the water balance in the rain floods. The problems that arise when comparing the results of observations and measurements of rainfall floods are considered. 2. We rely on the concept, where groundwater and surface water are the two coupled factors resulting in catastrophic floods/debris, and they are not isolated systems. These two units are closely related to each other on the territory of a unified watershed under its functioning including the overall transport system, i.e. 3D-network of cracks in the rock (visible manifestation on the land surface of which is the rivershed itself). 3. We estimated the pressure in the aquifer taking the data obtained by the observable mudflow or flood as a base. According to our calculations in the case of a violent release, such pressure for the really observed events can reach tens of atmospheres. Such pressure enhancement may occur due to various external factors (including the nature climatic and seismic processes). 4. A more detailed analysis should be carried out in accordance with a real topology of multiple cracks taking into account the non-stationary process and levels of resistance for water flows in different sections of crack-net (hydrostatic/hydrodynamic pressures in underground aquifers).

  9. SENSITIVITY OF THE REGIONAL WATER BALANCE IN THE COLUMBIA RIVER BASIN TO CLIMATE VARIABILITY: APPLICATION OF A SPATIALLY DISTRIBUTED WATER BALANCE MODEL

    EPA Science Inventory

    A one-dimensional water balance model was developed and used to simulate water balance for the Columbia River Basin. he model was run over a 10 km X 10 km grid for the United State's portion of the basin. he regional water balance was calculated using a monthly time-step for a re...

  10. Calculation of available water supply in crop root zone and the water balance of crops

    NASA Astrophysics Data System (ADS)

    Haberle, Jan; Svoboda, Pavel

    2015-12-01

    Determination of the water supply available in soils for crops is important for both the calculation of water balance and the prediction of water stress. An approach to calculations of available water content in layers of the root zone, depletion of water during growth, and water balance, with limited access to data on farms, is presented. Soil water retention was calculated with simple pedotransfer functions from the texture of soil layers, root depth, and depletion function were derived from observed data; and the potential evapotranspiration was calculated from the temperature. A comparison of the calculated and experimental soil water contents showed a reasonable fit.

  11. Water balance models in one-month-ahead streamflow forecasting.

    USGS Publications Warehouse

    Alley, W.M.

    1985-01-01

    Techniques are tested that incorporate information from water balance models in making 1-month-ahead streamflow forecasts in New Jersey. The results are compared to those based on simple autoregressive time series models. The relative performance of the models is dependent on the month of the year in question. -from Author

  12. Water--Problems and Solutions. A Report Concerning the Problems and Solutions of Negative Water Balance.

    ERIC Educational Resources Information Center

    Ewert, Alan

    Outdoor leaders constantly face problems created by water shortage and, to act effectively, must thoroughly understand the body's use of water and the ways to delay dehydration when water shortage occurs. Dehydration begins when there is a negative water balance, or more water lost than ingested, and progresses from the stage of dryness, to the…

  13. Rethinking the terrestrial water balance: Steps toward a comprehensive indicator framework

    NASA Astrophysics Data System (ADS)

    Weiskel, P. K.; Wolock, D.; Zarriello, P. J.; Vogel, R. M.; Brandt, S. L.

    2009-12-01

    Freshwater scarcity for humans and ecosystems is one of the most serious global challenges of the 21st century. Caused in part by human disturbance of the hydrologic cycle, patterns of water scarcity also reflect large, underlying variations in terrestrial water availability that precede human influence. In recent years, growing concerns about water scarcity have prompted the development and application of distributed, continental-to-global scale water balance models for water-resource assessment, fostering the important new sub-discipline of global hydrology. However, fundamental concepts of water availability have not kept pace with developments in modeling tools. To facilitate fundamental thinking and communication in this growing field, we introduce a new indicator framework based on a spatially distributed, time-dependent approach to the terrestrial water balance. The framework takes advantage of gridded climate, hydrology, and landscape data, is equally pertinent to dryland and humid regions of the world, and integrates traditional (runoff-based) and emerging perspectives on terrestrial water availability—including the blue/green water paradigm now gaining currency in the global water planning and management community. We derive the indicator framework from a general statement of the landscape water balance equation, and then illustrate the relevance of the framework to the extremely diverse hydroclimates of the conterminous United States.

  14. Large Scale Evapotranspiration Estimates: An Important Component in Regional Water Balances to Assess Water Availability

    NASA Astrophysics Data System (ADS)

    Garatuza-Payan, J.; Yepez, E. A.; Watts, C.; Rodriguez, J. C.; Valdez-Torres, L. C.; Robles-Morua, A.

    2013-05-01

    used in a "kind of" crop factor manner for all vegetation types (including agricultural fields). Finally, the model uses air temperature and humidity, both extracted from the North American Land Data Assimilation System (NLDAS) database. ET estimates were then compared to ground truth data from four sites where long-term Eddy Covariance (EC) measurements of ET were conducted. This approach was developed and applied in Northern Mexico. Emphasis was placed on trying to minimize the large uncertainties that still remained on the temporal evolution and the spatial repartition of ET. Results show good agreement with ground data (with r2 greater than 0.7 on daily ET estimates) from the four sites evaluated using different vegetation types hence reducing the spatial uncertainties. Estimates of total annual ET were used in a water balance, assessing ground water availability for eleven aquifers in the state of Chihuahua. Annual ET in a four-year analysis period, ranged from 200 to 280 mm/year, representing 63 to 83 % of total annual precipitation, which reflects the importance of this component in the water balance. A GIS tool kit is under development to support decision makers at CONAGUA.

  15. The Water Balance Portal in Saxony - An interactive web application concerning the impact of climate change on the water balance

    NASA Astrophysics Data System (ADS)

    Hauffe, Corina; Schwarze, Robert; Röhm, Patric; Müller, Ruben; Dröge, Werner; Gurova, Anastasia; Winkler, Peter; Baldy, Agnes

    2016-04-01

    Changes in weather and climate lead to increasing discussions about reasons and possible future impacts on the hydrological cycle. The question of a changed distribution of water also concerns the federal state of Saxony in the eastern part of Germany. Especially with a look at the different and increased requirements for water authorities, water economy and the public. To define and prepare these future requirements estimations of the future development of the natural water resources are necessary. Therefore data, information, and forecast concerning the development of the several components of the water balance are needed. And to make the obtained information easily available for experts and the public, tools like the internet have to be used. Under these frame conditions the water balance portal Saxony (www.wasserhaushaltsportal.sachsen.de) was developed within the project KliWES. The overall approach of the project was devided into the so-called „3 pillars".The first pillar focused on the evaluation of the status quo water balance from 1951-2005 by using a complex area-wide analysis of measured data. Also it contained the generating of a database and the development of a physically based parameter model. Furthermore an extensive model evaluation has been conducted with a number of objective assessment criteria, to select an appropriate model for the project. The second pillar included the calibration of the water balance model and the impact study of climate and land use change (1961-2100) on the water balance of Saxonian catchments. In this context 13 climate scenarios and three land use scenarios were simulated. The web presence of these two pillars represents a classical information service, which provides finalized results at the spatial resolution of sub-catchments using GIS-based webpages. The third pillar focused on the development of an interactive expert system. It allows the user (public, officials and consulting engineers) to simulate the water

  16. Socio-hydrological water balance for water allocation between human and environmental purposes in catchments

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Huang, Y.; Wei, Y.; Wang, G.

    2015-08-01

    Rebalancing water allocation between human consumptive uses and the environment in water catchments is a global challenge. This paper proposes a socio-hydrological water balance framework by partitioning catchment total evapotranspiration (ET) into ET for society and ET for natural ecological systems, and establishing the linkage between the changes of water balance and its social drivers and resulting environmental consequences in the Murray-Darling Basin (MDB), Australia, over the period 1900-2010. The results show that the 100-year period of water management in the MDB could be divided into four periods corresponding to major changes in basin management within the socio-hydrological water balance framework: period 1 (1900-1956) - expansion of water and land use for the societal system, period 2 (1956-1978) - maximization of water and land use for the societal system, period 3 (1978-2002) - maximization of water use for the societal system from water diversion, and period 4 (2002-present) - rebalancing of water and land use between the societal and ecological systems. Most of management changes in the MDB were passive and responsive. A precautionary approach to water allocation between the societal and ecological systems should be developed. The socio-hydrological water balance framework could serve as a theoretical foundation for water allocation to evaluate the dynamic balance between the societal and ecological systems in catchments.

  17. Characterization of floating element balance for field panel testing

    NASA Astrophysics Data System (ADS)

    Hunsucker, J. Travis; Gardner, Harrison; Swain, Geoffrey

    2015-11-01

    Multiple experiments were performed to investigate and characterize the uncertainty and bias of a through-hull flush mounted floating element balance designed to measure the hydrodynamic drag forces of biofouling and marine coatings on 25 x 30 cm test panels. The instrument is located in a wet well on the aft portion of a 27' Chris Craft Commander. Testing occurs over a series of speeds ranging from a Froude number of 0.50-2.20 on calm days (force 3 or less) in waters along the central east coast of Florida. Recent modifications have been made to the instrumentation in an effort to improve the overall accuracy of the system. This study compares frictional drag measurements of the floating element balance to those obtained using the Clauser chart and Preston tube methods for a smooth surface. Boundary layer velocity profiles are examined to understand the nature of the flow over the testing section. Roughness function values for 60 and 220 grit sandpaper were calculated from data obtained using the floating element balance. These values were compared with previous work to examine the overall bias of the methodology. Repeat measurements for a smooth panel were analyzed to characterize the overall uncertainty in the system. This research was supported by the Office of Naval Research under grants N00014-10-1-0919 and N00014-11-1-0915.

  18. The soil water balance in a mosaic of clumped vegetation

    NASA Astrophysics Data System (ADS)

    Pizzolla, Teresa; Manfreda, Salvatore; Caylor, Kelly; Gioia, Andrea; Iacobellis, Vito

    2014-05-01

    The spatio-temporal distribution of soil moisture influences the plant growth and the distribution of terrestrial vegetation. This effect is more evident in arid and semiarid ecosystems where the interaction between individuals and the water limited conditions play a fundamental role, providing environmental conditions which drive a variety of non-linear ecohydrological response functions (such as transpiration, photosynthesis, leakage). In this context, modeling vegetation patterns at multiple spatial aggregation scales is important to understand how different vegetation structures can modify the soil water distribution and the exchanged fluxes between soil and atmosphere. In the present paper, the effect of different spatial vegetation patterns, under different climatic scenarios, is investigated in a patchy vegetation mosaic generated by a random process of individual tree canopies and their accompanying root system. Vegetation pattern are generated using the mathematical framework proposed by Caylor et al. (2006) characterized by a three dimensional stochastic vegetation structure, based on the density, dispersion, size distribution, and allometry of individuals within a landscape. A Poisson distribution is applied to generate different distribution of individuals paying particular attention on the role of clumping on water distribution dynamics. The soil water balance is evaluated using the analytical expression proposed by Laio et al. (2001) to explore the influence of climate and vegetation patterns on soil water balance steady-state components (such as the average rates of evaporation, the root water uptake and leakage) and on the stress-weighted plant water uptake. Results of numerical simulations show that clumping may be beneficial for water use efficiency at the landscape scale. References Caylor, Kelly K., P. D'Odorico and I. Rodriguez Iturbe: On the ecohydrology of structurally heterogeneous semiarid landscape. Water Resour. Res., 28, W07424, 2006

  19. Near-surface water balance of an undeveloped upland site in west-central Florida

    USGS Publications Warehouse

    Bidlake, W.R.; Boetcher, P.F.

    1996-01-01

    A study was made to examine the near-surface water balance of a dry prairie site in west-central Florida. The water balance, which was defined on a unit area basis and for a depth of 5.5 meters, was described for the period June 1991 to October 1992. Precipitation during the 498 days of field measurements was 2,245 millimeters. Evapotranspiration, the second largest component, was 1,419 millimeters. Water yield was 808 millimeters and the change in soil water storage was 19 millimeters. Computed vertical water flux was less than 4 percent of evapotranspiration because of the small hydraulic conductivity of a clay layer that began at a depth of 5.5 meters.

  20. Water Quality Field Guide.

    ERIC Educational Resources Information Center

    Soil Conservation Service (USDA), Washington, DC.

    Nonpoint source pollution is both a relatively recent concern and a complex phenomenon with many unknowns. Knowing the extent to which agricultural sources contribute to the total pollutant load, the extent to which various control practices decrease this load, and the effect of reducing the pollutants delivered to a water body are basic to the…

  1. Ion and water balance in Gryllus crickets during the first twelve hours of cold exposure.

    PubMed

    Des Marteaux, Lauren E; Sinclair, Brent J

    2016-06-01

    Insects lose ion and water balance during chilling, but the mechanisms underlying this phenomenon are based on patterns of ion and water balance observed in the later stages of cold exposure (12 or more hours). Here we quantified the distribution of ions and water in the hemolymph, muscle, and gut in adult Gryllus field crickets during the first 12h of cold exposure to test mechanistic hypotheses about why homeostasis is lost in the cold, and how chill-tolerant insects might maintain homeostasis to lower temperatures. Unlike in later chill coma, hemolymph [Na(+)] and Na(+) content in the first few hours of chilling actually increased. Patterns of Na(+) balance suggest that Na(+) migrates from the tissues to the gut lumen via the hemolymph. Imbalance of [K(+)] progressed gradually over 12h and could not explain chill coma onset (a finding consistent with recent studies), nor did it predict survival or injury following 48h of chilling. Gryllus veletis avoided shifts in muscle and hemolymph ion content better than Gryllus pennsylvanicus (which is less chill-tolerant), however neither species defended water, [Na(+)], or [K(+)] balance during the first 12h of chilling. Gryllus veletis better maintained balance of Na(+) content and may therefore have greater tissue resistance to ion leak during cold exposure, which could partially explain faster chill coma recovery for that species. PMID:27039031

  2. GlobWat - a global water balance model to assess water use in irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Hoogeveen, J.; Faurès, J.-M.; Peiser, L.; Burke, J.; van de Giesen, N.

    2015-01-01

    GlobWat is a freely distributed, global soil water balance model that is used by FAO to assess water use in irrigated agriculture; the main factor behind scarcity of freshwater in an increasing number of regions. The model is based on spatially distributed high resolution datasets that are consistent at global level and calibrated against values for Internal Renewable Water Resources, as published in AQUASTAT, FAO's global information system on water and agriculture. Validation of the model is done against mean annual river basin outflows. The water balance is calculated in two steps: first a "vertical" water balance is calculated that includes evaporation from in situ rainfall ("green" water) and incremental evaporation from irrigated crops. In a second stage, a "horizontal" water balance is calculated to determine discharges from river (sub-)basins, taking into account incremental evaporation from irrigation, open water and wetlands ("blue" water). The paper describes methodology, input and output data, calibration and validation of the model. The model results are finally compared with other global water balance models.

  3. GlobWat - a global water balance model to assess water use in irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Hoogeveen, J.; Faurès, J.-M.; Peiser, L.; Burke, J.; van de Giesen, N.

    2015-09-01

    GlobWat is a freely distributed, global soil water balance model that is used by the Food and Agriculture Organization (FAO) to assess water use in irrigated agriculture, the main factor behind scarcity of freshwater in an increasing number of regions. The model is based on spatially distributed high-resolution data sets that are consistent at global level and calibrated against values for internal renewable water resources, as published in AQUASTAT, the FAO's global information system on water and agriculture. Validation of the model is done against mean annual river basin outflows. The water balance is calculated in two steps: first a "vertical" water balance is calculated that includes evaporation from in situ rainfall ("green" water) and incremental evaporation from irrigated crops. In a second stage, a "horizontal" water balance is calculated to determine discharges from river (sub-)basins, taking into account incremental evaporation from irrigation, open water and wetlands ("blue" water). The paper describes the methodology, input and output data, calibration and validation of the model. The model results are finally compared with other global water balance models to assess levels of accuracy and validity.

  4. Reconnaissance water-balance study of Lake Gregory, California

    USGS Publications Warehouse

    McConaughy, C.E.

    1982-01-01

    A study was made to determine the magnitude and distribution of the surface-water inflow and outflow (water balance) of the Lake Gregory basin in southern California. Data were collected from April 1979 through June 1981. Runoff during the study period varied greatly with the majority of inflow occurring between December and May of each year. During 1980 and 1981 (through July 1981) precipitation totals at Lake Gregory were the maximum and minimum for the 19-year period of record. The average annual precipitation for the 3-year period 1979-81 was 47.4 inches, almost 10 inches greater than the long-term average, 1962-81, of 37.8 inches. Surface-water runoff in the Lake Gregory basin is highly dependent on annual precipitation, and total outflow for the 1980 water year and partial total for the 1981 (through June) water year was 7,230 acre-feet and 400 acre-feet, respectively. (USGS)

  5. Mass-balance model for predicting nitrate in ground water

    USGS Publications Warehouse

    Frimpter, Michael H.; Donohue, John J.; Rapacz, Michael V.

    1990-01-01

    A mass-balance accounting model can be used to guide the management of septic systems and fertilizers to control the degradation of ground-water quality in zones of an aquifer that contribute water to public-supply wells. The nitrate concentration of the mixture in the well can be predicted for steady-state conditions by calculating the concentration that results from the total weight of nitrogen and total volume of water entering the zone of contribution to the well. These calculations will allow water-quality managers to predict the nitrate concentrations that would be produced by different types and levels of development, and to plan development accordingly. Computations for different development schemes provide a technical basis for planners and managers to compare water-quality effects and to select alternatives that limit nitrate concentration in wells.

  6. Megacity project: Liwa, climate and water balance modeling

    NASA Astrophysics Data System (ADS)

    Chamorro, Alejandro; Bardossy, Andras

    2010-05-01

    Megacity project: Liwa, climate and water balance modeling Peru uses to face different natural phenomena such as El Nino and La Nina phenomena and, like many cities around the word, the climate change effects. Its capital Lima, located in a region where annual precipitation is about 9 mm, has a high hydrological cycle vulnerability which is demonstrated in periods of drought and extreme drought. Accurate and reliable methodology is requiring studying the impact of all these problems in the water supply of Lima. A statistical downscaling scheme (Bardossy, 2002) will be used to generate time series of different local climate scenarios in order to be applied in hydrological models. The conceptual model HBV (Bergström, 1995) is used to simulate water discharges at certain points of the catchments under study, water balance groundwater and for the estimation of storage volume in different reservoirs. As already mentioned, El Nino and La Nina currents influence the hydrological cycle. Previous studies have shown that these phenomena have serious impacts in Peru. In order to quantify these impacts in the area of interest we have analyzed the magnitude of the precipitation in several stations in years in which El Nino occurred, and in years where El Nino did not occurred. The next step is to increase the temporal resolution by incorporating new data. Due to the high vulnerability of the water supply system in Lima, potential new water sources are required. In particular, the catchment of Mantaro (including existing lakes) on the other side of Los Andes Mountains provides potential new alternatives for adding water to the current system. Alternatives for water transportation include using existing long tunnels which connect Mantaro with Rimac, where the majority of the lakes are located. Finally, the global climate models simulations for the coming years, considering different scenarios, will be used as an indicator and to estimate water availability for human use (city

  7. Field Balancing in the Real World: Part 2

    SciTech Connect

    Bracher, R.K.; Surrett, C.L.

    1999-10-06

    This paper is a follow-up to an earlier paper, Field Balancing in the Real World, which was presented at CSI Reliability Week 1997 in Nashville. Case studies of excessive vibrations on fans at ORNL will be discussed. Except for a few small sections from the earlier paper, this paper is entirely new. The case studies are new. As in the first paper, all fans are rigid-rotor type fans. Normal operation, therefore, is at less than the shaft's first critical speed. The presentation of case studies with root cause problems other than unbalance is a major departure from the first paper. We believe they belong here, since unbalance is suspected most of the time when a fan is vibrating excessively, even when it is not the root cause. In reality, unbalance is the underlying cause of the excess vibration on fans we have fixed at ORNL only about half the time. Furthermore, the analyst's credibility could be called into question upon an unsuccessful attempt at field balancing when underlying causes are later discovered and fixed. A demonstration will follow the case study presentation. The additional tests described in this paper to confirm centrifugal force (probable unbalance) will be performed.

  8. BALANCE

    DOEpatents

    Carmichael, H.

    1953-01-01

    A torsional-type analytical balance designed to arrive at its equilibrium point more quickly than previous balances is described. In order to prevent external heat sources creating air currents inside the balance casing that would reiard the attainment of equilibrium conditions, a relatively thick casing shaped as an inverted U is placed over the load support arms and the balance beam. This casing is of a metal of good thernnal conductivity characteristics, such as copper or aluminum, in order that heat applied to one portion of the balance is quickly conducted to all other sensitive areas, thus effectively preventing the fornnation of air currents caused by unequal heating of the balance.

  9. Regionalization of the Turc-Mezentsev water balance formula

    NASA Astrophysics Data System (ADS)

    Lebecherel, Laure; Andréassian, Vazken

    2013-04-01

    equation for annual evaporation using field observations and results from a biophysical model. Journal of Hydrology, 216(1-2): 99-110. Donohue, R., Roderick, M., McVicar, T., 2011. Assessing the differences in sensitivities of runoff to changes in climatic conditions across a large basin. J. Hydrol., 406(3-4): 234-244. Dooge, J.C.I., 1992. Sensitivty of runoff to climate change - A Hortonian approach. Bull. Amer. Meteorol. Soc., 73(12): 2013-2024. Mezentsev, V., 1955. More on the computation of actual evaporation (Yechio raz o rastchetie srednevo summarnovo ispareniia). Meteorologia i Gidrologia, 5: 24-26. Oudin, L., Andréassian, V., Lerat, J., Michel, C., 2008. Has land cover a significant impact on mean annual streamflow? An international assessment using 1508 catchments. Journal of Hydrology, 357(3-4): 303-316. Potter, N.J., Zhang, L., 2009. Interannual variability of catchment water balance in Australia. Journal of Hydrology, 369: 120-129. Roderick, M.L., Farquhar, G.D., 2011. A simple framework for relating variations in runoff to variations in climatic conditions and catchment properties. Water Resour. Res., 47. Turc, L., 1954. Le bilan d'eau des sols: relation entre les précipitations, l'évaporation et l'écoulement. Annales Agronomiques, Série A(5): 491-595.

  10. Validation of two energy balance closure parameterisations using field measurements

    NASA Astrophysics Data System (ADS)

    Eder, Fabian; De Roo, Frederik; Kohnert, Katrin; Desjardins, Raymond L.; Foken, Thomas; Schmid, Hans Peter; Mauder, Matthias

    2013-04-01

    Eddy Covariance (EC) measurements often do not close the energy balance. This indicates that surface heat fluxes are underestimated, likely because large-scale eddies and stationary circulations are not captured. Because EC is a widespread tool in environmental science to assess energy fluxes and trace gas budgets, it is essential to quantify the 'missing' fluxes. In the literature, two approaches to parameterise the lack of energy balance closure can be found. The first one by Huang et al (2008) is based on large-eddy simulations (LES) and perceives the energy imbalance as being the result of large-scale turbulent organized structures. The second approach by Panin and Bernhofer (2008) suggests an empirical approach which focuses on surface roughness heterogeneities on the landscape-scale. We tested both approaches with EC data from three sites, located in southern Germany, of the Terrestrial Environmental Observatories (TERENO) programme. Additionally, we applied the parameterisations to aircraft data from Canada, which were conducted as part of the Boreal Ecosystem-Atmosphere Study (BOREAS) experiment and the Boreal Ecosystem Research and Monitoring Sites (BERMS) programme. For each flight, the flux contribution of turbulent structures larger than 2 km, determined by wavelet analysis, serves as an estimate of the missing flux of conventional EC measurements. In most cases, the two parameterisations do not give a reliable prediction of the energy balance residual. The approach of Panin and Bernhofer (2008) disregards topographical effects, differences in surface moisture and surface temperature and thus, it cannot explain the poor energy balance closure of the TERENO sites. However, above the flat terrain of the airborne measurements in Canada, it works surprisingly well. The parameterisation by Huang et al (2008) was developed for homogeneous terrain, a condition which is almost never met in field studies. In addition, there is a general mismatch between LES and

  11. Sodium and water balance in chronic congestive heart failure.

    PubMed Central

    Cody, R J; Covit, A B; Schaer, G L; Laragh, J H; Sealey, J E; Feldschuh, J

    1986-01-01

    As the characteristics of sodium and water balance in heart failure remain undefined, we evaluated the hemodynamic, metabolic, and hormonal effects of balanced sodium intake in 10 patients with chronic congestive heart failure. We discontinued diuretics to avoid their confounding influence, and all patients received 1 wk of 10 meq and 100 meq balanced sodium intake and controlled free water. Comparing sodium intake of 10 with 100 meq, the following observations were made. There was weight gain (2.0 kg) and increased sodium excretion (11 +/- 3 to 63 +/- 15 meq/24 h), unaccompanied by increase of blood volume. Both renin-angiotensin system and sympathetic nervous system activity were greater during the 10 meq diet, and suppressed with the 100 meq sodium diet. For both diets, plasma renin and urinary aldosterone excretion were correlated with urinary sodium excretion (r = -0.768, r = -0.726, respectively; P less than 0.005). Systemic hemodynamics were minimally changed with increased sodium intake. However, reversal of vasoconstriction by captopril during the 10 meq diet, and its ineffectiveness during the 100 meq diet, indicated a renin-dependent mechanism in the former, and a renin-independent mechanism in the latter diet. There were two subgroups of response to the 100 meq diet: one group (n = 5) achieved neutral balance, while the second (n = 5) avidly retained sodium and water. Renin-angiotensin system activity was significantly higher in the latter group, and the mechanism for differences in sodium excretion for the subgroups could not be identified by blood volume or hemodynamic parameters. Orthostatic hypotension during tilt was greater during the 10 meq sodium diet, and in all cases, related to ineffective hemodynamic and hormonal compensatory responses. PMID:3517066

  12. Modeling the water balance of a small Pinus radiata catchment.

    PubMed

    Whitehead, D.; Kelliher, F. M.

    1991-01-01

    An hourly biophysical model was used to calculate the water balance over a period of one year for an 8.7-ha catchment with a closed-canopy, 13-year-old Pinus radiata D. Don forest in the central North Island, New Zealand. Components of the model are transpiration from the dry tree canopy, evaporation from the partially wet tree canopy and stems, evaporation from the understory and soil, and drainage from a single-layer root zone. The model requires input of hourly weather data (net radiation, air and wet bulb temperatures, windspeed, and rainfall), tree stand characteristics (average height, tree number, leaf area index), physical characteristics of the site (root zone depth, relationship between root zone matric potential and volumetric water content, the relationship between the rate of drainage from the root zone and volumetric water content, and the area of open-stream channels). A submodel of the response of stomatal conductance to air saturation deficit and root zone matric potential is also required. Tree transpiration (704 mm year(-1) or 50% of annual rainfall) was a dominant component of the catchment water balance. Estimated evaporation from the wet tree canopy was 203 mm year(-1) (15%). Evaporation from the understory was much less, amounting to 94 mm year(-1) (7%) and an increase in water storage for the 3.5 m root zone depth was estimated to be 53 mm year(-1) (4%). Estimated daily rates of drainage generally agreed well with measurements of streamflow, although estimated annual drainage (349 mm year(-1), 24%) exceeded measured streamflow (234 mm year(-1)). The significance of the results is discussed in relation to closure of the hydrologic balance. PMID:14972854

  13. Water balance measurements and simulations of maize plants on lysimeters

    NASA Astrophysics Data System (ADS)

    Heinlein, Florian; Biernath, Christian; Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2016-04-01

    In Central Europe expected major aspects of climate change are a shift of precipitation events and amounts towards winter months, and the general increase of extreme weather events like heat waves or summer droughts. This will lead to strongly changing regional water availability and will have an impact on future crop growth, water use efficiency and yields. Therefore, to estimate future crop yields by growth models accurate descriptions of transpiration as part of the water balance is important. In this study, maize was grown on weighing lysimeters (sowdate: 24 April 2013). Transpiration was determined by sap flow measurement devices (ICT International Pty Ltd, Australia) using the Heat-Ratio-Method: two temperature probes, 0.5 cm above and below a heater, detect a heat pulse and its speed which allows the calculation of sap flow. Water balance simulations were executed with different applications of the model framework Expert-N. The same pedotransfer and hydraulic functions and the same modules to simulate soil water flow, soil heat and nitrogen transport, nitrification, denitrification and mineralization were used. Differences occur in the chosen potential evapotranspiration ETpot (Penman-Monteith ASCE, Penman-Monteith FAO, Haude) and plant modules (SPASS, CERES). In all simulations ETpot is separated into a soil and a plant part using the leaf are index (LAI). In a next step, these parts are reduced by soil water availability. The sum of these parts is the actual evapotranspiration ETact which is compared to the lysimeter measurements. The results were analyzed from Mid-August to Mid-September 2013. The measured sap flow rates show clear diurnal cycles except on rainy days. The SPASS model is able to simulate these diurnal cycles, overestimates the measurements on rainy days and at the beginning of the analyzed period, and underestimates transpiration on the other days. The main reason is an overestimation of potential transpiration Tpot due to too high

  14. Modeling of Water balance in semiarid region of Mexico

    NASA Astrophysics Data System (ADS)

    González-Sosa, E.; Mastachi-Loza, C.; Medina-frutos, C.; Ramos-Salinas, N. M.

    2012-04-01

    Around the world water is becoming scarce, especially in the semiarid regions where there is a high inter-annual variability in the amount and distribution of the rainfall. Studies on this kind of environments would allow us to understand the mechanisms that determine the spatial and temporal distribution of the water balance components. The present study was carried out from October 2005 to October 2008 in three semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Amazcala and Cadereyta in the State of Queretaro. The work aim was to provide a better understanding of the hydrological processes that occur in the semiarid ecosystems, specifically through two objectives (1) to quantify and to model the rainfall interception process (EI) employing an adequate sampling strategy and an evaluation of the models developed by Rutter et al. (1975) and Gash (1979) in two shrubs species: huisache (Acacia farnesisna) and mesquite (Prosopis laevigata) both, in situ and ex situ and (2) to quantify and model the water balance in order to define the distribution of the water and energy balance components in El Carmen and Cadereyta. For this purpose, the SiSPAT (Simple Soil Plant Atamosphere Transfer) model was used based on a parametrisation of the soil, plants and atmosphere components. It was found that EI represented between 20% and 22% of the total rainfall (PG). Gash's model reproduced EI with satisfactory efficiency (E>0.6), wind's speed and maximum intensity have a local effect on EI. It was also found that, using SiSPAT, the water balance components were particularly sensitive to parameters associated with the soil and the leaf area index. The model results showed that during the studied period, the annual evapotranspiration in Cadereyta was less than PG (-10 and -5%) and above PG for El Carmen (10 y 30%). Runoff and percolation at 5m were null. Finally in both sites there was a simulated loss of water stored in the soil. This, was

  15. The water balance of the Dead Sea: an integrated approach

    NASA Astrophysics Data System (ADS)

    Al-Weshah, Radwan A.

    2000-01-01

    The Dead Sea is the lowest spot on Earth. It is a closed saline lake located in the middle of the Jordan Rift Valley between Lake Tiberias and the Red Sea. Its major tributaries are the Jordan River itself and the Dead Sea side wadis. The Dead Sea has a unique ecosystem and its water has curative, industrial and recreational significance. The level of the Dead Sea has been continuously falling since the early 1930s at an average rate of 0·7 m per year. The water level, as of February 1998, is about 410·9 m below mean sea level. In this paper, a water balance model is developed for the Dead Sea by considering different hydrological components of this water balance, including precipitation, runoff, evaporation and groundwater flow. This model is calibrated based on historical levels of the Dead Sea. Different scenarios are investigated, including the proposed Dead Sea-Red Sea Canal. This project is supposed to halt the shrinking of the Dead Sea and restore it to pre-1950 levels in the next century.

  16. Balancing water resource conservation and food security in China.

    PubMed

    Dalin, Carole; Qiu, Huanguang; Hanasaki, Naota; Mauzerall, Denise L; Rodriguez-Iturbe, Ignacio

    2015-04-14

    China's economic growth is expected to continue into the next decades, accompanied by sustained urbanization and industrialization. The associated increase in demand for land, water resources, and rich foods will deepen the challenge of sustainably feeding the population and balancing agricultural and environmental policies. We combine a hydrologic model with an economic model to project China's future food trade patterns and embedded water resources by 2030 and to analyze the effects of targeted irrigation reductions on this system, notably on national agricultural water consumption and food self-sufficiency. We simulate interprovincial and international food trade with a general equilibrium welfare model and a linear programming optimization, and we obtain province-level estimates of commodities' virtual water content with a hydrologic model. We find that reducing irrigated land in regions highly dependent on scarce river flow and nonrenewable groundwater resources, such as Inner Mongolia and the greater Beijing area, can improve the efficiency of agriculture and trade regarding water resources. It can also avoid significant consumption of irrigation water across China (up to 14.8 km(3)/y, reduction by 14%), while incurring relatively small decreases in national food self-sufficiency (e.g., by 3% for wheat). Other researchers found that a national, rather than local, water policy would have similar effects on food production but would only reduce irrigation water consumption by 5%. PMID:25825748

  17. Balancing water resource conservation and food security in China

    PubMed Central

    Dalin, Carole; Qiu, Huanguang; Hanasaki, Naota; Mauzerall, Denise L.; Rodriguez-Iturbe, Ignacio

    2015-01-01

    China’s economic growth is expected to continue into the next decades, accompanied by sustained urbanization and industrialization. The associated increase in demand for land, water resources, and rich foods will deepen the challenge of sustainably feeding the population and balancing agricultural and environmental policies. We combine a hydrologic model with an economic model to project China’s future food trade patterns and embedded water resources by 2030 and to analyze the effects of targeted irrigation reductions on this system, notably on national agricultural water consumption and food self-sufficiency. We simulate interprovincial and international food trade with a general equilibrium welfare model and a linear programming optimization, and we obtain province-level estimates of commodities’ virtual water content with a hydrologic model. We find that reducing irrigated land in regions highly dependent on scarce river flow and nonrenewable groundwater resources, such as Inner Mongolia and the greater Beijing area, can improve the efficiency of agriculture and trade regarding water resources. It can also avoid significant consumption of irrigation water across China (up to 14.8 km3/y, reduction by 14%), while incurring relatively small decreases in national food self-sufficiency (e.g., by 3% for wheat). Other researchers found that a national, rather than local, water policy would have similar effects on food production but would only reduce irrigation water consumption by 5%. PMID:25825748

  18. A Root Zone Water Balance Algorithm for Educational Settings.

    ERIC Educational Resources Information Center

    Cahoon, Joel E.; Ferguson, Richard B.

    1995-01-01

    Describes a simple technique for monitoring root zone water status on demonstration project fields and incorporating the demonstration site results into workshop-type educational settings. Surveys indicate the presentation was well received by demonstration project cooperators and educators. (LZ)

  19. Drinking and water balance during exercise and heat acclimation

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Brock, P. J.; Keil, L. C.; Morse, J. T.

    1983-01-01

    The interactions between fluid intake and balance, and plasma ion, osmotic, and endocrine responses during dehydration produced by exercise in cool and warm environments during acclimation are explored. Two groups of five male subjects performed 8 days of ergometer exercise in hot and thermoneutral conditions, respectively. The exercise trials lasted 2 hr each. Monitoring was carried out on the PV, osmotic, sodium, and endocrine concentrations, voluntary fluid intake, fluid balances, and fluid deficits. A negative correlation was observed between the plasma sodium and osmolality during acclimation. The presence of hypervolemia during acclimation is suggested as a cause of drinking, while the vasopressin concentration was not found to be a significant factor stimulating drinking. Finally, the predominant mechanism in fluid intake during exercise and heat exposure is concluded to be the renin-angiotensin II system in the presence of reductions in total body water and extracellular plasma volumes.

  20. Snowpack energy balance analysis using field measurements in an Andean watershed

    NASA Astrophysics Data System (ADS)

    Stehr, Alejandra

    2014-05-01

    Depending on the relative altitude and ambient temperature, Andean watersheds present important snow coverage during winter season. Snowpack stores significant amount of water which is released to surface runoff and groundwater when solar radiation increases, mainly during the spring and summer season, controlling the shape of the annual hydrograph and affecting the water balance at monthly and shorter scales. Field measurements of snow cover in those areas are difficult to perform due to adverse climatic and topographic conditions. Therefore, it is useful to support the hydrological characterization of watersheds located in the high mountains with models representing runoff from melting, for example, models based on the energy balance of the snowpack. The objective of this work is to characterize and quantify the energy flows that control the accumulation and melting of snow cover, using field measurements. The work was done on the upper Malleco watershed, which is located in the Andes Mountain Range (38°20' - 38°41' S and 71°13' - 71°35' W) and has an area of 27 km2, elevations vary between 900 to 1789 m a.m.s.l. For the calculation of the different the energy balance components, two weather stations were installed in the study area, which recorded data every 15 minutes. The variables measured were: global solar radiation, net radiation, shortwave and longwave radiation, air temperature, relative humidity, wind speed and direction, soil heat flux, precipitation and snow depth. Two analyzes were performed: 1) Energy Balance 2010. Two representative periods of accumulation (1st July to 31st July) and melting (10 September to 10 October) were selected in one of the stations. 2) Energy Balance 2011. Energy balance for a 15 days period of accumulation (July 19 to August 3, 2011) was with the aim of comparing both meteorological stations. In all cases hourly energy fluxes, snow water equivalent and daily snow depth were calculated. The latter was compared with the

  1. Water balance and irrigation water pumping of Lake Merdada for potato farming in Dieng Highland, Indonesia.

    PubMed

    Fadlillah, Lintang N; Widyastuti, M

    2016-08-01

    Lakes provide water resources for domestic use, livestock, irrigational use, etc. Water availability of lakes can be estimated using lake water balance. Lake water balance is calculated from the water input and output of a lake. Dieng Highland has several volcanic lakes in its surroundings. Lake Merdada in Dieng Highland has been experiencing extensive water pumping for several years more than other lakes in the surrounding area. It provides irrigation water for potato farming in Dieng Highland. The hydrological model of this lake has not been studied. The modeled water balance in this research uses primary data, i.e., bathymetric data, soil texture, and outflow discharge, as well as secondary data, i.e., rainfall, temperature, Landsat 7 ETM+ band 8 image, and land use. Water balance input components consist of precipitation on the surface area, surface (direct) runoff from the catchment area, and groundwater inflow and outflow (G net), while the output components consist of evaporation, river outflow, and irrigation. It shows that groundwater is the dominant input and output of the lake. On the other hand, the actual irrigation water pumping plays the leading role as human-induced alteration of outflow discharge. The maximum irrigation pumping modeling shows that it will decrease lake storage up to 37.14 % per month and may affect the ecosystem inside the lake. PMID:27384226

  2. A Monthly Water-Balance Model Driven By a Graphical User Interface

    USGS Publications Warehouse

    McCabe, Gregory J.; Markstrom, Steven L.

    2007-01-01

    This report describes a monthly water-balance model driven by a graphical user interface, referred to as the Thornthwaite monthly water-balance program. Computations of monthly water-balance components of the hydrologic cycle are made for a specified location. The program can be used as a research tool, an assessment tool, and a tool for classroom instruction.

  3. Analysis of the water balance of Lake Victoria

    NASA Astrophysics Data System (ADS)

    Nossent, J.; de Brabanter, W.; Bauwens, W.

    2009-04-01

    Lake Victoria is situated within an elevated plateau in the western part of Africa's Great Rift Valley and lies within the territory of three countries: Tanzania, Uganda and Kenya. It is Africa's largest lake and the second widest fresh water lake in the world in terms of surface area. It is also the source of the longest branch of the River Nile, the White Nile. The lake's shallowness, limited river inflow, and large surface area relative to its volume make it vulnerable to climate changes and fluctuations of the water level. This affects the surrounding countries and their people a lot, especially in terms of their food supply and economy. The aim of this study was to get more information on the causes of these fluctuations by analysing the water balance of the lake for the period 1970-1974. It was based both on historical data and measurements and new calculations, and compared with previous studies (e.g. Suttcliffe and Parks, 1999). Precipitation and evaporation over the lake surface were calculated with the Thiessen Polygons method, using measurements from stations around the lake and on the islands. The total inflow of the lake is the sum of the contributions of twelve subbasins. One of these subcatchments, the Nzoia-catchment, was modeled with SWAT (Soil and Water Assessment Tool), a physically based, semi-distributed river basin simulator, as a contribution to the development of a water balance model for Lake Victoria. To calculate the outflow at the Owen Falls Dam in Jinja (Uganda), gauge heights of the lake were used in combination with the "Agreed Curve" (the relationship between water level and flow that was set by the policy makers). As the lake is assumed to be a system with a closed mass balance, the combination of the variations in the above mentioned components resulted in changes of the lake's storage, leading to fluctuations of the water level. For the period 1970-1974 the calculated mean monthly evaporation is 133 mm, with a standard deviation

  4. A balanced water layer concept for subglacial hydrology in large scale ice sheet models

    NASA Astrophysics Data System (ADS)

    Goeller, S.; Thoma, M.; Grosfeld, K.; Miller, H.

    2012-12-01

    There is currently no doubt about the existence of a wide-spread hydrological network under the Antarctic ice sheet, which lubricates the ice base and thus leads to increased ice velocities. Consequently, ice models should incorporate basal hydrology to obtain meaningful results for future ice dynamics and their contribution to global sea level rise. Here, we introduce the balanced water layer concept, covering two prominent subglacial hydrological features for ice sheet modeling on a continental scale: the evolution of subglacial lakes and balance water fluxes. We couple it to the thermomechanical ice-flow model RIMBAY and apply it to a synthetic model domain inspired by the Gamburtsev Mountains, Antarctica. In our experiments we demonstrate the dynamic generation of subglacial lakes and their impact on the velocity field of the overlaying ice sheet, resulting in a negative ice mass balance. Furthermore, we introduce an elementary parametrization of the water flux-basal sliding coupling and reveal the predominance of the ice loss through the resulting ice streams against the stabilizing influence of less hydrologically active areas. We point out, that established balance flux schemes quantify these effects only partially as their ability to store subglacial water is lacking.

  5. Semi-arid vegetation response to antecedent climate and water balance windows

    USGS Publications Warehouse

    Thoma, David P.; Munson, Seth M.; Irvine, Kathryn M.; Witwicki, Dana L.; Bunting, Erin

    2016-01-01

    Questions Can we improve understanding of vegetation response to water availability on monthly time scales in semi-arid environments using remote sensing methods? What climatic or water balance variables and antecedent windows of time associated with these variables best relate to the condition of vegetation? Can we develop credible near-term forecasts from climate data that can be used to prepare for future climate change effects on vegetation? Location Semi-arid grasslands in Capitol Reef National Park, Utah, USA. Methods We built vegetation response models by relating the normalized difference vegetation index (NDVI) from MODIS imagery in Mar–Nov 2000–2013 to antecedent climate and water balance variables preceding the monthly NDVI observations. We compared how climate and water balance variables explained vegetation greenness and then used a multi-model ensemble of climate and water balance models to forecast monthly NDVI for three holdout years. Results Water balance variables explained vegetation greenness to a greater degree than climate variables for most growing season months. Seasonally important variables included measures of antecedent water input and storage in spring, switching to indicators of drought, input or use in summer, followed by antecedent moisture availability in autumn. In spite of similar climates, there was evidence the grazed grassland showed a response to drying conditions 1 mo sooner than the ungrazed grassland. Lead times were generally short early in the growing season and antecedent window durations increased from 3 mo early in the growing season to 1 yr or more as the growing season progressed. Forecast accuracy for three holdout years using a multi-model ensemble of climate and water balance variables outperformed forecasts made with a naïve NDVI climatology. Conclusions We determined the influence of climate and water balance on vegetation at a fine temporal scale, which presents an opportunity to forecast vegetation

  6. Estimating Agricultural Water Use using the Operational Simplified Surface Energy Balance Evapotranspiration Estimation Method

    NASA Astrophysics Data System (ADS)

    Forbes, B. T.

    2015-12-01

    Due to the predominantly arid climate in Arizona, access to adequate water supply is vital to the economic development and livelihood of the State. Water supply has become increasingly important during periods of prolonged drought, which has strained reservoir water levels in the Desert Southwest over past years. Arizona's water use is dominated by agriculture, consuming about seventy-five percent of the total annual water demand. Tracking current agricultural water use is important for managers and policy makers so that current water demand can be assessed and current information can be used to forecast future demands. However, many croplands in Arizona are irrigated outside of areas where water use reporting is mandatory. To estimate irrigation withdrawals on these lands, we use a combination of field verification, evapotranspiration (ET) estimation, and irrigation system qualification. ET is typically estimated in Arizona using the Modified Blaney-Criddle method which uses meteorological data to estimate annual crop water requirements. The Modified Blaney-Criddle method assumes crops are irrigated to their full potential over the entire growing season, which may or may not be realistic. We now use the Operational Simplified Surface Energy Balance (SSEBop) ET data in a remote-sensing and energy-balance framework to estimate cropland ET. SSEBop data are of sufficient resolution (30m by 30m) for estimation of field-scale cropland water use. We evaluate our SSEBop-based estimates using ground-truth information and irrigation system qualification obtained in the field. Our approach gives the end user an estimate of crop consumptive use as well as inefficiencies in irrigation system performance—both of which are needed by water managers for tracking irrigated water use in Arizona.

  7. Observed and modeled multi-year evaporation from three field-scale experiments using water balance and Penman-Monteith methods: Profound effect of material type and wind exposure

    NASA Astrophysics Data System (ADS)

    Peterson, H. E.; Fretz, N.; Bay, D.; Mayer, K. U.; Smith, L.; Beckie, R. D.

    2013-12-01

    Three instrumented experimental waste-rock piles at the Cu-Zn-Mo Antamina Mine in Peru are composed of distinct types of waste rock but are otherwise almost identical in size and geometry and experience the same atmospheric conditions with the exception of wind exposure. Evaporation from the piles was calculated using the water balance method over three- and four-year periods to determine the effect of material type and meteorological variability on evaporation. Annual changes in water storage were low or negligible except as a result of unusually high annual precipitation. Observed evaporation was high (44% - 75% of precipitation) and was extremely variable annually in the coarsest-grained waste-rock pile 1, most likely as a result of greater wind exposure and air circulation in that pile. Observed evaporation was moderate (36% - 48% of precipitation) with moderate annual variability in the finer-grained, relatively homogeneous waste-rock pile 2. Observed evaporation was low (24% - 32% of precipitation) with low annual variability in the finer-grained, relatively heterogeneous waste-rock pile 3, most likely as a result of low air circulation coupled with complex flow regimes that include high-velocity preferential flow paths. Slightly higher evaporation was observed on the slopes than on the crowns of Pile 2, while much lower evaporation was observed on the slopes than on the crowns of Piles 1 and 3. Evidence suggests that Piles 1 and 3 slope water-balance evaporation estimates are skewed by non-vertical flow and that, in general, evaporation is higher on the slopes than on the crowns of the piles. Evaporation was also estimated using the Food and Agriculture Organization of the United Nations modified Penman-Monteith method (FAO-PM; Allen et al., 1998) using base-case laboratory- and software- derived parameters. The base-case method underestimated observed evaporation calculated by the water balance method for Pile 1, overestimated observed evaporation for Pile

  8. Monthly Water Balance Model Portal for the United States

    NASA Astrophysics Data System (ADS)

    Hay, L.; Bock, A.; Markstrom, S. L.; McCabe, G. J., Jr.; Atkinson, D.

    2014-12-01

    The Monthly Water Balance Model (MWBM) portal delivers MWBM output generated for current and future climatic conditions for stream segments and hydrologic response units derived from the US Geological Survey's National Hydrologic Model Geospatial Fabric. The MWBM is a modular system that provides monthly estimates of components of the hydrologic cycle (e.g. streamflow, potential and actual evapotranspiration, snowpack, and storage) computed from mean monthly temperature, monthly total precipitation, latitude, and available soil water capacity. The MWBM portal can generate reports and graphics using simulations from more than 200 current and future climate scenarios at any location within the contiguous US. This presentation will introduce users to the MWBM portal and demonstrate how to access and download MWBM portal data.

  9. Seawater drinking restores water balance in dehydrated harp seals.

    PubMed

    How, Ole-Jakob; Nordøy, Erling S

    2007-07-01

    The purpose of this study was to answer the question of whether dehydrated harp seals (Phoca groenlandica) are able to obtain a net gain of water from the intake of seawater. Following 24 h of fasting, three subadult female harp seals were dehydrated by intravenous administration of the osmotic diuretic, mannitol. After another 24 h of fasting, the seals were given 1,000 ml seawater via a stomach tube. Urine and blood were collected for measurement of osmolality and osmolytes, while total body water (TBW) was determined by injections of tritiated water. In all seals, the maximum urinary concentrations of Na(+) and Cl(-) were higher than in seawater, reaching 540 and 620 mM, respectively, compared to 444 and 535 mM in seawater. In another experiment, the seals were given ad lib access to seawater for 48 h after mannitol-induced hyper-osmotic dehydration. In animals without access to seawater, the mean blood osmolality increased from 331 to 363 mOsm kg(-1) during dehydration. In contrast, the blood osmolality, hematocrit and TBW returned to normal when the seals were permitted ad lib access to seawater after dehydration. In conclusion, this study shows that harp seals have the capacity to gain net water from mariposa (voluntarily drinking seawater) and are able to restore water balance after profound dehydration by drinking seawater. PMID:17375309

  10. A worldwide analysis of trends in water-balance evapotranspiration

    NASA Astrophysics Data System (ADS)

    Ukkola, A. M.; Prentice, I. C.

    2013-05-01

    Climate change is expected to alter the global hydrological cycle, with inevitable consequences for freshwater availability to people and ecosystems. But the attribution of recent trends in the terrestrial water balance remains disputed. This study attempts to account statistically for both trends and interannual variability in water-balance evapotranspiration (ET), estimated from the annual observed streamflow in 109 river basins during "water years" 1961-1999 and two gridded precipitation datasets. The basins were chosen based on the availability of streamflow time-series data in the Dai et al. (2009) synthesis. They were divided into water-limited "dry" and energy-limited "wet" basins following the Budyko framework. We investigated the potential roles of precipitation, aerosol-corrected solar radiation, land-use change, wind speed, air temperature, and atmospheric CO2. Both trends and variability in ET show strong control by precipitation. There is some additional control of ET trends by vegetation processes, but little evidence for control by other factors. Interannual variability in ET was overwhelmingly dominated by precipitation, which accounted on average for 52-54% of the variation in wet basins (ranging from 0 to 99%) and 84-85% in dry basins (ranging from 13 to 100%). Precipitation accounted for 39-42% of ET trends in wet basins and 69-79% in dry basins. Cropland expansion increased ET in dry basins. Net atmospheric CO2 effects on transpiration, estimated using the Land-surface Processes and eXchanges (LPX) model, did not contribute to observed trends in ET because declining stomatal conductance was counteracted by slightly but significantly increasing foliage cover.

  11. A worldwide analysis of trends in water-balance evapotranspiration

    NASA Astrophysics Data System (ADS)

    Ukkola, A. M.; Prentice, I. C.

    2013-10-01

    Climate change is expected to alter the global hydrological cycle, with inevitable consequences for freshwater availability to people and ecosystems. But the attribution of recent trends in the terrestrial water balance remains disputed. This study attempts to account statistically for both trends and interannual variability in water-balance evapotranspiration (ET), estimated from the annual observed streamflow in 109 river basins during "water years" 1961-1999 and two gridded precipitation data sets. The basins were chosen based on the availability of streamflow time-series data in the Dai et al. (2009) synthesis. They were divided into water-limited "dry" and energy-limited "wet" basins following the Budyko framework. We investigated the potential roles of precipitation, aerosol-corrected solar radiation, land use change, wind speed, air temperature, and atmospheric CO2. Both trends and variability in ET show strong control by precipitation. There is some additional control of ET trends by vegetation processes, but little evidence for control by other factors. Interannual variability in ET was overwhelmingly dominated by precipitation, which accounted on average for 54-55% of the variation in wet basins (ranging from 0 to 100%) and 94-95% in dry basins (ranging from 69 to 100%). Precipitation accounted for 45-46% of ET trends in wet basins and 80-84% in dry basins. Net atmospheric CO2 effects on transpiration, estimated using the Land-surface Processes and eXchanges (LPX) model, did not contribute to observed trends in ET because declining stomatal conductance was counteracted by slightly but significantly increasing foliage cover.

  12. Internal water balance of barley under soil moisture stress.

    PubMed

    Millar, A A; Duysen, M E; Wilkinson, G E

    1968-06-01

    Leaf water potential, leaf relative water content, and relative transpiration of barley were determined daily under greenhouse conditions at 3 growth stages: tillering to boot, boot to heading, and heading to maturity. The leaf moisture characteristic curve (relative water content versus leaf water potential) was the same for leaves of the same age growing in the same environment for the first 2 stages of growth, but shifted at the heading to maturity stage to higher leaf relative water content for a given leaf water potential. Growth chamber experiments showed that the leaf moisture characteristic curve was not the same for plants growing in different environments.Relative transpiration data indicated that barley stomates closed at a water potential of about -22 bars at the 3 stages studied.The water potential was measured for all the leaves on barley to determine the variation of water potential with leaf position. Leaf water potential increased basipetally with plant leaf position. In soil with a moisture content near field capacity a difference of about 16.5 bars was observed between the top and bottom leaves on the same plant, while in soil with a moisture content near the permanent wilting point the difference was only 5.6 bars between the same leaf positions. PMID:16656869

  13. Impact of microwave derived soil moisture on hydrologic simulations using a spatially distributed water balance model

    NASA Technical Reports Server (NTRS)

    Lin, D. S.; Wood, E. F.; Famiglietti, J. S.; Mancini, M.

    1994-01-01

    Spatial distributions of soil moisture over an agricultural watershed with a drainage area of 60 ha were derived from two NASA microwave remote sensors, and then used as a feedback to determine the initial condition for a distributed water balance model. Simulated hydrologic fluxes over a period of twelve days were compared with field observations and with model predictions based on a streamflow derived initial condition. The results indicated that even the low resolution remotely sensed data can improve the hydrologic model's performance in simulating the dynamics of unsaturated zone soil moisture. For the particular watershed under study, the simulated water budget was not sensitive to the resolutions of the microwave sensors.

  14. On the Capabilities of Using AIRSAR Data in Surface Energy/Water Balance Studies

    NASA Technical Reports Server (NTRS)

    Moreno, Jose F.; Saatchi, Sasan S.

    1996-01-01

    In this paper an algorithm is described that allows derivation of three fundamental parameters from synthetic aperture radar (SAR) data: soil moisture, soil roughness, and canopy water content, accounting for the effects of vegetation cover by using optical (Landsat) data as auxiliary. The capabilities and limitations of the data and algorithms are discussed, as well as possibilities to use these data in energy/water balance modeling studies. All of the data used in this study was acquired as part of the European Field Experiment in a Desertification Threatened Area.

  15. Water Balance Change in Xia Ying River Basin, Qinghai Province, China

    NASA Astrophysics Data System (ADS)

    Cuo, L.; Zhou, B.; Li, J.

    2010-12-01

    Yellow River, Yangtze River and Lan Cang River are major river systems supporting billions of people in South East Asia and China. Source region of Yellow River, Yangtze River and Lan Cang River (Three Rivers) is located in Qinghai Province, China. Recently, Chinese government started a conservation project in the source region of the Three Rivers called “Convert Agricultural Field to Forest and Grassland”. Xia Ying River Basin is a sub-basin located in the source region of the Three River Basin. The upper Xia Ying River Basin has experienced dramatic land cover change since 2006. Before 2006, upper Xia Ying River Basin hill slope was agricultural field. Coniferous trees and bush vegetation were planted on the slope greater than 70 degree in the upper Xia Ying River Basin in 2006. The objective of the study is to investigate the water balance term change in the Xia Ying River Basin because of the conservation project. This study will use Landsat and MODIS imagery to classify and quantify land cover classes before and after land cover conversion. Water balance terms including runoff and evaportranspiration will be simulated using a land surface model to investigate water balance term change due to land cover change. The study serves as a pilot study for the investigation of hydrological change in the entire source region of the Three River Basin during the past 50 years.

  16. Field calibration accuracy and utility for four down-hole water content sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil water balance studies aimed at determining crop water use, spatial variability of water use, profile water content, and changes in stored water demand accurate soil water determinations that are representative across at least field sized areas. Several capacitance and other electromagnetic (EM)...

  17. Evaluating Water Conservation and Reuse Policies Using a Dynamic Water Balance Model

    NASA Astrophysics Data System (ADS)

    Qaiser, Kamal; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria R.

    2013-02-01

    A dynamic water balance model is created to examine the effects of different water conservation policies and recycled water use on water demand and supply in a region faced with water shortages and significant population growth, the Las Vegas Valley (LVV). The model, developed using system dynamics approach, includes an unusual component of the water system, return flow credits, where credits are accrued for returning treated wastewater to the water supply source. In LVV, Lake Mead serves as, both the drinking water source and the receiving body for treated wastewater. LVV has a consumptive use allocation from Lake Mead but return flow credits allow the water agency to pull out additional water equal to the amount returned as treated wastewater. This backdrop results in a scenario in which conservation may cause a decline in the available water supply. Current water use in LVV is 945 lpcd (250 gpcd), which the water agency aims to reduce to 752 lpcd (199 gpcd) by 2035, mainly through water conservation. Different conservation policies focused on indoor and outdoor water use, along with different population growth scenarios, are modeled for their effects on the water demand and supply. Major contribution of this study is in highlighting the importance of outdoor water conservation and the effectiveness of reducing population growth rate in addressing the future water shortages. The water agency target to decrease consumption, if met completely through outdoor conservation, coupled with lower population growth rate, can potentially satisfy the Valley's water demands through 2035.

  18. Aquatic Exposure Predictions of Insecticide Field Concentrations Using a Multimedia Mass-Balance Model.

    PubMed

    Knäbel, Anja; Scheringer, Martin; Stehle, Sebastian; Schulz, Ralf

    2016-04-01

    Highly complex process-driven mechanistic fate and transport models and multimedia mass balance models can be used for the exposure prediction of pesticides in different environmental compartments. Generally, both types of models differ in spatial and temporal resolution. Process-driven mechanistic fate models are very complex, and calculations are time-intensive. This type of model is currently used within the European regulatory pesticide registration (FOCUS). Multimedia mass-balance models require fewer input parameters to calculate concentration ranges and the partitioning between different environmental media. In this study, we used the fugacity-based small-region model (SRM) to calculate predicted environmental concentrations (PEC) for 466 cases of insecticide field concentrations measured in European surface waters. We were able to show that the PECs of the multimedia model are more protective in comparison to FOCUS. In addition, our results show that the multimedia model results have a higher predictive power to simulate varying field concentrations at a higher level of field relevance. The adaptation of the model scenario to actual field conditions suggests that the performance of the SRM increases when worst-case conditions are replaced by real field data. Therefore, this study shows that a less complex modeling approach than that used in the regulatory risk assessment exhibits a higher level of protectiveness and predictiveness and that there is a need to develop and evaluate new ecologically relevant scenarios in the context of pesticide exposure modeling. PMID:26889709

  19. Water balance dynamics of a boreal forest watershed: White Gull Creek basin, 1994-1996

    NASA Astrophysics Data System (ADS)

    Nijssen, Bart; Lettenmaier, Dennis P.

    2002-11-01

    Field measurements from the Boreal Ecosystem-Atmosphere Study (BOREAS) were combined to calculate the water balance of the White Gull Creek basin for the three year period 1994-1996. Evapotranspiration was mapped from the observations made at the BOREAS flux towers to the basin using a simple evaporation model with a bulk canopy resistance based on tower observations. Runoff ratios were low, and evapotranspiration accounted for most of the precipitation over the area. The accumulated storage change, over the 3 year period, was 47 mm or 3.4% of the total precipitation, but precipitation exceeded the sum of discharge and evapotranspiration by 80 mm or 15% of the precipitation in 1994. Five possible explanations for the discrepancy in the water balance are identified, with the most likely cause an underestimation of the evapotranspiration in 1994, especially during periods when the basin is wet.

  20. Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

    NASA Technical Reports Server (NTRS)

    Fisher, John W.; Hogan, John Andrew; Wignarajah, Kanapathipi; Pace, Gregory S.

    2010-01-01

    Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

  1. Energy Balance Concept in the Evaluation of Water Table Management Effects on Corn Growth: Experimental Investigation

    NASA Astrophysics Data System (ADS)

    Kalita, Prasanta K.; Kanwar, Rameshwar S.

    1992-10-01

    The effects of water table management practices (WTMP) on corn growth in 1989 and 1990 at two field sites, Ames and Ankeny, Iowa, were evaluated by calculating crop water stress index (CWSI) and monitoring plant physiological parameters during the growing seasons. Experiments were conducted on field lysimeters at the Ames site by maintaining water tables at 0.3-, 0.6-, and 0.9-m depths and in a subirrigation field at the Ankeny site with 0.2-, 0.3-, 0.6-, 0.9-, and 1.1-m water table depths, and periodically measuring leaf and air temperature, transpiration rate, stomatal conductance, and photosynthetically active radiation (PAR) using leaf chamber techniques. Net radiation of canopy was estimated using the leaf energy balance equation and leaf chamber measurements and then correlated with PAR. Analysis of data revealed that net radiation, leaf air temperature differential, transpiration rate, stomatal conductance, and CWSI were strongly related to WTMP during vegetative and flowering stages of corn growth. Excess water in the root zone with a water table depth of 0.2 m caused the maximum crop water stress and ceased crop growth. Both water and oxygen could be adequately maintained for favorable crop growth by adopting the best WTMP. Results indicate that plant physiological parameters and CWSI could be used to evaluate the effectiveness of WTMP and develop the best WTMP for corn growth in the humid region.

  2. Global Energy and Water Balances in the Latest Reanalyses

    NASA Astrophysics Data System (ADS)

    Ahn, Joong-Bae; Kang, Suchul; Park, Hye-Jin

    2016-04-01

    The recently released Japanese 55-year Reanalysis (JRA-55) data are evaluated and compared with three other global reanalyses, namely Interim version of the next European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERRA-Interim), Modern Era Retrospective-Analysis for Research and Applications (MERRA) and Climate Forecast System Reanalysis (CFSR), in terms of global energy and water balances. All four reanalyses show an energy imbalance at TOA and surface. Especially, clouds in JRA-55 are optically weaker than those in the three other reanalyses, leading to excessive outgoing longwave radiation, which in turn causes negative net energy flux at TOA. Moreover, JRA-55 has a negative imbalance at surface and at TOA, which is attributed to systematic positive biases in latent heat flux over the ocean. As for the global water balance, all reanalyses present a similar spatial pattern of the difference between evaporation and precipitation (E-P). However, JRA-55 has a relatively strong negative (positive) E-P in the Intertropical Convergence Zone and South Pacific Convergence Zone (extratropical regions) due to overestimated precipitation (evaporation), in spite of the global net being close to zero. In time series analysis, especially in E-P, significant stepwise changes occur in MERRA, CFSR and ERA-Interim due to the changes occur in MERRA, CFRS and ERA-Interim due to the changes in the satellite observing system used in the data assimilation. Both MERRA and CFSR show a strong downward E-P shift in 1998, simultaneously with the start of the assimilation of AMSU-A sounding radiances. ERA-Interim exhibits an upward E-P shift in 1992 due to changes in observations from the SSM/I of new DMSP satellites. On the contrary, JRA-55 exhibits less trends and remains stable over time, which may be caused by newly available, homogenized observations and advances in data assimilation technique. Acknowledgements This work was funded by the Korea Meteorological

  3. Simple Cell Response Properties Imply Receptive Field Structure: Balanced Gabor and/or Bandlimited Field Functions

    PubMed Central

    Cope, Davis; Blakeslee, Barbara; McCourt, Mark E.

    2011-01-01

    The classical receptive fields of simple cells in mammalian primary visual cortex demonstrate three cardinal response properties: 1) they do not respond to stimuli which are spatially homogeneous; 2) they respond best to stimuli in a preferred orientation (direction); and 3) they do not respond to stimuli in other, non-preferred orientations (directions). We refer to these as the Balanced Field Property, the Maximum Response Direction Property, and the Zero Response Direction Property, respectively. These empirically-determined response properties are used to derive a complete characterization of elementary receptive field functions (of cosine- and mixed-type) defined as products of a circularly symmetric weight function and a simple periodic carrier. Two disjoint classes of elementary receptive field functions result: the balanced Gabor class, a generalization of the traditional Gabor filter, and a bandlimited class whose Fourier transforms have compact support (i.e., are zero-valued outside of a bounded range). The detailed specification of these two classes of receptive field functions from empirically-based postulates may prove useful to neurophysiologists seeking to test alternative theories of simple cell receptive field structure, and to computational neuroscientists seeking basis functions with which to model human vision. PMID:19721693

  4. Nanoconfined water under electric field

    NASA Astrophysics Data System (ADS)

    Luzar, Alenka; Bratko, D.; Daub, C. D.

    2010-03-01

    We study the effect of electric field on interfacial tension of nanoconfined water [1,2] using molecular simulations. Our analysis and simulations confirm that classical electrostriction characterizes usual electrowetting behavior in nanoscale hydrophobic channels and nanoporous materials [3]. We suggest a new mechanism to orient nanoparticles by an applied electric field even when the particles carry no charges or dipoles of their own. Coupling to the field can be accomplished trough solvent-mediated interaction between the electric field and a nanoparticle [4]. For nanoscale particles in water, we find the response to the applied field to be sufficiently fast to make this mechanism relevant for biological processes, design of novel nanostructures and sensors, and development of nanoengineering methods [5]. [1]C. D. Daub, D. Bratko, K. Leung and A. Luzar, J. Phys. Chem. C 111, 505 (2007). [2] D. Bratko, C. D. Daub, K. Leung and A. Luzar, J. Am. Chem. Soc. 129, 2504 (2007) [3] D. Bratko, C. D. Daub and A. Luzar, Phys. Chem. Chem. Phys. 10, 6807 (2008). [4] D. Bratko, C. D. Daub and A. Luzar, Faraday Discussions 141, 55 (2009). [5] C. D. Daub, D. Bratko, T. Ali and A. Luzar, Phys. Rev. Lett. 103, 207801 (2009).

  5. Global energy and water balances in the latest reanalyses

    NASA Astrophysics Data System (ADS)

    Kang, Suchul; Ahn, Joong-Bae

    2015-11-01

    The recently released Japanese 55-year Reanalysis (JRA- 55) data are evaluated and compared with three other global reanalyses, namely Interim version of the next European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim), Modern Era Retrospective-Analysis for Research and Applications (MERRA) and Climate Forecast System Reanalysis (CFSR), in terms of global energy and water balances. All four reanalyses show an energy imbalance at TOA and surface. Especially, clouds in JRA-55 are optically weaker than those in the three other reanalyses, leading to excessive outgoing longwave radiation, which in turn causes negative net energy flux at TOA. Moreover, JRA-55 has a negative imbalance at surface and at TOA, which is attributed to systematic positive biases in latent heat flux over the ocean. As for the global water balance, all reanalyses present a similar spatial pattern of the difference between evaporation and precipitation (E-P). However, JRA-55 has a relatively strong negative (positive) E-P in the Intertropical Convergence Zone and South Pacific Convergence Zone (extratropical regions) due to overestimated precipitation (evaporation), in spite of the global net being close to zero. In time series analysis, especially in E-P, significant stepwise changes occur in MERRA, CFSR and ERA-Interim due to the changes in the satellite observing system used in the data assimilation. Both MERRA and CFSR show a strong downward E-P shift in 1998, simultaneously with the start of the assimilation of AMSU-A sounding radiances. ERA-Interim exhibits an upward E-P shift in 1992 due to changes in observations from the SSM/I of new DMSP satellites. On the contrary, JRA-55 exhibits less trends and remains stable over time, which may be caused by newly available, homogenized observations and advances in data assimilation technique.

  6. On the advantage of well-balanced schemes for moving-water equilibria of the shallow water equations

    SciTech Connect

    Xing, Yulong; Shu, Chi-wang; Noelle, Sebastian

    2011-01-01

    This note aims at demonstrating the advantage of moving-water well-balanced schemes over still-water well-balanced schemes for the shallow water equations. We concentrate on numerical examples with solutions near a moving-water equilibrium. For such examples, still-water well-balanced methods are not capable of capturing the small perturbations of the moving-water equilibrium and may generate significant spurious oscillations, unless an extremely refined mesh is used. On the other hand, moving-water well-balanced methods perform well in these tests. The numerical examples in this note clearly demonstrate the importance of utilizing moving-water well-balanced methods for solutions near a moving-water equilibrium.

  7. Biogeochemical mass balances in a turbid tropical reservoir. Field data and modelling approach

    NASA Astrophysics Data System (ADS)

    Phuong Doan, Thuy Kim; Némery, Julien; Gratiot, Nicolas; Schmid, Martin

    2014-05-01

    The turbid tropical Cointzio reservoir, located in the Trans Mexican Volcanic Belt (TMVB), behaves as a warm monomictic water body (area = 6 km2, capacity 66 Mm3, residence time ~ 1 year). It is strategic for the drinking water supply of the city of Morelia, capital of the state of Michoacán, and for downstream irrigation during the dry season. This reservoir is a perfect example of a human-impacted system since its watershed is mainly composed of degraded volcanic soils and is subjected to high erosion processes and agricultural loss. The reservoir is threatened by sediment accumulation and nutrients originating from untreated waters in the upstream watershed. The high content of very fine clay particles and the lack of water treatment plants lead to serious episodes of eutrophication (up to 70 μg chl. a L-1), high levels of turbidity (Secchi depth < 30 cm) and a long period of anoxia (from May to October). Based on intensive field measurements in 2009 (deposited sediment, benthic chamber, water vertical profiles, reservoir inflow and outflow) we determined suspended sediment (SS), carbon (C), nitrogen (N) and phosphorus (P) mass balances. Watershed SS yields were estimated at 35 t km2 y-1 of which 89-92 % were trapped in the Cointzio reservoir. As a consequence the reservoir has already lost 25 % of its initial storage capacity since its construction in 1940. Nutrient mass balances showed that 50 % and 46 % of incoming P and N were retained by sedimentation, and mainly eliminated through denitrification respectively. Removal of C by 30 % was also observed both by sedimentation and through gas emission. To complete field data analyses we examined the ability of vertical one dimensional (1DV) numerical models (Aquasim biogeochemical model coupled with k-ɛ mixing model) to reproduce the main biogeochemical cycles in the Cointzio reservoir. The model can describe all the mineralization processes both in the water column and in the sediment. The values of the

  8. Water balance calculations and net production of perennial vegetation in the northern Mojave Desert

    SciTech Connect

    Lane, L.J.; Romney, E.M.; Hakonson, T.E.

    1984-01-01

    Measurements obtained between 1968 and 1976 indicate the influence of climatic factors and soil characteristics upon soil moisture and production of perennial vegetation in the northern Mojave Desert. Seasonal distribution patterns of precipitation are shown to have a strong effect on plant-available soil moisture, and these patterns are, in turn, reflected in net production of perennial vegetation. Available climatic data and soil characteristics were used as input to a continuous simulation model to calculate the water balance for a unit area watershed. Computed and measured soil moisture agreed quite well over a rangeof values from close to the wilting point to near field capacity. The authors used computed evapo-transpiration rates to estimate water use by perennial vegetation. Computed water use was multiplied by a water use efficiency factor to estimate net production of perennial vegetation. Estimated net production exhibited year-to-year variability comparable with measured values, and agreed quite closely with available observations. This paper briefly describes soil-water-plant relationships in the northern Mojave Desert and illustrates an application of a continuous simulation model to predict soil moisture and net production of perennial vegetation. Based on the authors analysis, the simulation model would appear to have potential for estimating the water balance and above ground net primary production on arid and semiarid rangelands. 21 references, 5 figures, 5 tables.

  9. Balancing

    NASA Astrophysics Data System (ADS)

    Harteveld, Casper

    At many occasions we are asked to achieve a “balance” in our lives: when it comes, for example, to work and food. Balancing is crucial in game design as well as many have pointed out. In games with a meaningful purpose, however, balancing is remarkably different. It involves the balancing of three different worlds, the worlds of Reality, Meaning, and Play. From the experience of designing Levee Patroller, I observed that different types of tensions can come into existence that require balancing. It is possible to conceive of within-worlds dilemmas, between-worlds dilemmas, and trilemmas. The first, the within-world dilemmas, only take place within one of the worlds. We can think, for example, of a user interface problem which just relates to the world of Play. The second, the between-worlds dilemmas, have to do with a tension in which two worlds are predominantly involved. Choosing between a cartoon or a realistic style concerns, for instance, a tension between Reality and Play. Finally, the trilemmas are those in which all three worlds play an important role. For each of the types of tensions, I will give in this level a concrete example from the development of Levee Patroller. Although these examples come from just one game, I think the examples can be exemplary for other game development projects as they may represent stereotypical tensions. Therefore, to achieve harmony in any of these forthcoming games, it is worthwhile to study the struggles we had to deal with.

  10. The water balance components of undisturbed tropical woodlands in the Brazilian Cerrado

    NASA Astrophysics Data System (ADS)

    Oliveira, P. T. S.; Wendland, E.; Nearing, M. A.; Scott, R. L.; Rosolem, R.; da Rocha, H. R.

    2014-11-01

    Deforestation of the Brazilian Cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood, but are important for making land management decisions in this region. To understand pre-deforestation conditions, we determined the main components of the water balance for an undisturbed tropical woodland classified as "cerrado sensu stricto denso". We developed an empirical model to estimate actual evapotranspiration (ET) by using flux tower measurements and, vegetation conditions inferred from the enhanced vegetation index and reference evapotranspiration. Canopy interception, throughfall, stemflow, surface runoff, and water table level were assessed from ground measurements. We used data from two Cerrado sites, "Pé de Gigante" - PDG and "Instituto Arruda Botelho" - IAB. Flux tower data from the PDG site collected from 2001 to 2003 was used to develop the empirical model to estimate ET. The other hydrological processes were measured at the field scale between 2011 and 2014 in the IAB site. The empirical model showed significant agreement (R2= 0.73) with observed ET at the daily scale. The average values of estimated ET at the IAB site ranged from 1.91 to 2.60 mm d-1 for the dry and wet season, respectively. Canopy interception ranged from 4 to 20% and stemflow values were approximately 1% of gross precipitation. The average runoff coefficient was less than 1%, while Cerrado deforestation has the potential to increase that amount up to 20 fold. As relatively little excess water runs off (either by surface water or groundwater) the water storage may be estimated by the difference between precipitation and evapotranspiration. Our results provide benchmark values of water balance dynamics in the undisturbed Cerrado that will be useful to evaluate past and future land cover and land use changes for this region.

  11. The water balance components of undisturbed tropical woodlands in the Brazilian cerrado

    NASA Astrophysics Data System (ADS)

    Oliveira, P. T. S.; Wendland, E.; Nearing, M. A.; Scott, R. L.; Rosolem, R.; da Rocha, H. R.

    2015-06-01

    Deforestation of the Brazilian cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood but are important for making land management decisions in this region. To better understand pre-deforestation conditions, we determined the main components of the water balance for an undisturbed tropical woodland classified as "cerrado sensu stricto denso". We developed an empirical model to estimate actual evapotranspiration (ET) by using flux tower measurements and vegetation conditions inferred from the enhanced vegetation index and reference evapotranspiration. Canopy interception, throughfall, stemflow, surface runoff, and water table level were assessed from ground measurements. We used data from two cerrado sites, Pé de Gigante (PDG) and Instituto Arruda Botelho (IAB). Flux tower data from the PDG site collected from 2001 to 2003 were used to develop the empirical model to estimate ET. The other hydrological processes were measured at the field scale between 2011 and 2014 at the IAB site. The empirical model showed significant agreement (R2 = 0.73) with observed ET at the daily timescale. The average values of estimated ET at the IAB site ranged from 1.91 to 2.60 mm day-1 for the dry and wet seasons, respectively. Canopy interception ranged from 4 to 20 % and stemflow values were approximately 1 % of the gross precipitation. The average runoff coefficient was less than 1 %, while cerrado deforestation has the potential to increase that amount up to 20-fold. As relatively little excess water runs off (either by surface water or groundwater), the water storage may be estimated by the difference between precipitation and evapotranspiration. Our results provide benchmark values of water balance dynamics in the undisturbed cerrado that will be useful to evaluate past and future land-cover and land-use changes for this region.

  12. Mechanism for negative water balance during weightlessness An hypothesis

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1986-01-01

    The mechanism for the apparent decrease in body fluid volume in astronauts during spaceflight remains obscure. The widespread postulate that the hypohydration is the result of the Henry-Gauer reflex, a diuresis caused by inhibition of vasopressin secretion resulting from increased left and perhaps right atrial (central) venous pressure, has not been established with direct measurements on astronauts. An hypothesis is proposed to account for fluid-electrolyte shifts during weightlessness. A moderate but transient increase in central venous pressure occurs when orbit is entered that is insufficient to activate the Henry-Gauer reflex but sufficient to stimulate the release of atrial natriuretic peptides. Increased sodium excretion would facilitate some increased urinary water loss. The resulting relatively dilute plasma and interstitial fluids would cause fluid to shift into the cellular space, resulting in edema in the head and trunk and inhibition of thirst and drinking. Thus, the negative water balance in astronauts would be caused by a gradual natriuresis and diuresis coupled with reduced fluid intake.

  13. A TEN-YEAR WATER BALANCE OF A MOUNTAINOUS SEMI-ARID WATERSHED. (R824784)

    EPA Science Inventory

    Quantifying water balance components, which is particularly challenging in snow-fed, semi-arid regions, is crucial to understanding the basic hydrology of a watershed. In this study, a water balance was computed using 10 years of data collected at the Upper Sheep Creek Water...

  14. Characterization of arid land water-balance processes at Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Flint, Alan L.; Flint, Lorraine E.; Hevesi, Joseph A.; Hudson, David B.

    Water-balance processes were characterized to estimate net infiltration at Yucca Mountain, Nevada, to help determine the suitability of this site as a potential high-level radioactive waste repository. Detailed water-content data were collected from 98 boreholes located in four topographic positions (ridgetops, sideslopes, albvial terraces, and active channels) representing four infiltration zones. These data include monthly volumetric water-content readings with depth for 1984 through 1995 and water potential measurements made at a soil-bedrock contact in 1995. These data, combined with measured evapotranspiration and precipitation data, piovide the seasonal and areal distribution of changes in volumetric water content needed to assess hydrologic processes contributing to net infiltration. The conceptual model of infiltration at Yucca Mountain describes the processes of precipitation, runoff, evapotranspiration, and vertical redistribution of water in the shallow unsaturated zone. Field observations and measurements and data analysis indicate that, in order for net infiltration to occur, water must reach and nearly saturate the soil-bedrock contact to initiate flow in the underlying fractured bedrock, and water must penetrate deep enough to escape the influences of evapotranspiration. The amount of net infiltration is a function of how long or how frequently the contact is saturated. Water must penetrate deep enough to escape the influences of evapotranspiration. The penetration of water through the soil is influenced primarily by the seasonal timing and areal distribution of precipitation, the storage capacity of soil, and the properties of the underlying bedrock.

  15. Field Balancing of Magnetically Levitated Rotors without Trial Weights

    PubMed Central

    Fang, Jiancheng; Wang, Yingguang; Han, Bangcheng; Zheng, Shiqiang

    2013-01-01

    Unbalance in magnetically levitated rotor (MLR) can cause undesirable synchronous vibrations and lead to the saturation of the magnetic actuator. Dynamic balancing is an important way to solve these problems. However, the traditional balancing methods, using rotor displacement to estimate a rotor's unbalance, requiring several trial-runs, are neither precise nor efficient. This paper presents a new balancing method for an MLR without trial weights. In this method, the rotor is forced to rotate around its geometric axis. The coil currents of magnetic bearing, rather than rotor displacement, are employed to calculate the correction masses. This method provides two benefits when the MLR's rotation axis coincides with the geometric axis: one is that unbalanced centrifugal force/torque equals the synchronous magnetic force/torque, and the other is that the magnetic force is proportional to the control current. These make calculation of the correction masses by measuring coil current with only a single start-up precise. An unbalance compensation control (UCC) method, using a general band-pass filter (GPF) to make the MLR spin around its geometric axis is also discussed. Experimental results show that the novel balancing method can remove more than 92.7% of the rotor unbalance and a balancing accuracy of 0.024 g mm kg−1 is achieved.

  16. Water Balance of Shrinking Thermkorst Ponds near Council, Alaska

    NASA Astrophysics Data System (ADS)

    Fraver, M. R.; Hinzman, L. D.; Yoshikawa, K.; Kane, D. L.

    2003-12-01

    Water balances were conducted on a wetland complex near Council, Alaska on the Seward Peninsula during the 2001 and 2002 summers in order to investigate the possibility of groundwater drainage through open taliks. This study is a product of the Arctic Transition in the Land-Atmosphere System (ATLAS) initiation within the Land Atmosphere Ice Interactions (LAII) flux program, created to understand the feedbacks within the land-atmosphere system in arctic regions and to predict reasonable scenarios resulting from future global climate change. The majority of ponds in the Council area are displaying a decreased surface area when compared with aerial photographs from the 1950's, and because the long-term temperature and precipitation data from Nome does not reveal any conclusive trends, the cause of this change is hypothesized to be related to the local permafrost and thermokarst conditions. From permafrost boring data, DC electrical sounding studies, and ground penetrating radar (GPR) surveys, the permafrost in the area is typically 20 to 60 meters thick, and underneath the shrinking thermokarst ponds are large thawed regions (taliks), most of which extend through the local permafrost (open taliks). Downward vertical gradients have been identified in the open taliks, indicating the downward migration of water from the ponds to the subpermafrost groundwater. It was hypothesized that this water loss mechanism is significant in the hydrologic dynamics of the ponds and is related to the recent drying of the ponds. The results of this two-year study, however, demonstrate that evapotranspiration and lateral drainage are capable of accounting for 100% of the observed storage changes.

  17. A monthly water balance model for climate change analysis in Hungary

    NASA Astrophysics Data System (ADS)

    Herceg, András; Kalicz, Péter; Kisfaludi, Balázs; Gribovszki, Zoltán

    2015-04-01

    The currently ongoing climate changing progress can be typified with a global temperature rising. The most significant effect of the climate change will impact for the water cycle. The analysis of the effects of vegetation on the hydrological cycle in a climate change context is especially important. In Hungary the impact of vegetation on water balance was analyzed in the frame of small catchment research as well as paired plot analysis. The aim of this paper was to a model develop based on Thorntwaite-type monthly water balance estimations. The main goals were to calibrate the model parameters, using remote sensing based ET dataset. The calibrated model was used for prediction using 4 climate model datasets. The 3 main periods of prediction were: 2010-2040, 2040-2070, and 2070-2100. The advantage of this model is its robust build-up. It can be applied if temperature and precipitation time series are available. The parameter of the calibration is the water storage capacity of the soil (SOILmax), which can be calibrated using the available actual evapotranspiration data. If the soils physical properties are known, the maximal rooting depth is also predictable. The model can primarily be used at the catchment level or for areas without additional water amounts from below. For testing the model, a dataset of a corn field next to Mosonmagyaróvár, and a dataset of a small forest covered catchment next to Sopron was successfully used. The latter can be used for water balance validation too. This publication has been supported by AGRARKLIMA.2 VKSZ_12-1-2013-0034 project.

  18. Soil Water Balance and Water Use Efficiency of Dryland Wheat in Different Precipitation Years in Response to Green Manure Approach

    PubMed Central

    Zhang, Dabin; Yao, Pengwei; Na, Zhao; Cao, Weidong; Zhang, Suiqi; Li, Yangyang; Gao, Yajun

    2016-01-01

    Winter wheat (Triticum aestivum L.) monoculture is conventionally cultivated followed by two to three months of summer fallow in the Loess Plateau. To develop a sustainable cropping system, we conducted a six-year field experiment to investigate the effect of leguminous green manure (LGM) instead of bare fallow on the yield and water use efficiency (WUE) of winter wheat and the soil water balance (SWB) in different precipitation years in a semi-arid region of northwest China. Results confirmed that planting LGM crop consumes soil water in the fallow season can bring varied effects to the subsequent wheat. The effect is positive or neutral when the annual precipitation is adequate, so that there is no significant reduction in the soil water supplied to wheat. If this is not the case, the effect is negative. On average, the LGM crop increased wheat yield and WUE by 13% and 28%, respectively, and had considerable potential for maintaining the SWB (0–200 cm) compared with fallow management. In conclusion, cultivation of the LGM crop is a better option than fallow to improve the productivity and WUE of the next crop and maintain the soil water balance in the normal and wet years in the Loess Plateau. PMID:27225842

  19. Soil Water Balance and Water Use Efficiency of Dryland Wheat in Different Precipitation Years in Response to Green Manure Approach.

    PubMed

    Zhang, Dabin; Yao, Pengwei; Na, Zhao; Cao, Weidong; Zhang, Suiqi; Li, Yangyang; Gao, Yajun

    2016-01-01

    Winter wheat (Triticum aestivum L.) monoculture is conventionally cultivated followed by two to three months of summer fallow in the Loess Plateau. To develop a sustainable cropping system, we conducted a six-year field experiment to investigate the effect of leguminous green manure (LGM) instead of bare fallow on the yield and water use efficiency (WUE) of winter wheat and the soil water balance (SWB) in different precipitation years in a semi-arid region of northwest China. Results confirmed that planting LGM crop consumes soil water in the fallow season can bring varied effects to the subsequent wheat. The effect is positive or neutral when the annual precipitation is adequate, so that there is no significant reduction in the soil water supplied to wheat. If this is not the case, the effect is negative. On average, the LGM crop increased wheat yield and WUE by 13% and 28%, respectively, and had considerable potential for maintaining the SWB (0-200 cm) compared with fallow management. In conclusion, cultivation of the LGM crop is a better option than fallow to improve the productivity and WUE of the next crop and maintain the soil water balance in the normal and wet years in the Loess Plateau. PMID:27225842

  20. Soil Water Balance and Water Use Efficiency of Dryland Wheat in Different Precipitation Years in Response to Green Manure Approach

    NASA Astrophysics Data System (ADS)

    Zhang, Dabin; Yao, Pengwei; Na, Zhao; Cao, Weidong; Zhang, Suiqi; Li, Yangyang; Gao, Yajun

    2016-05-01

    Winter wheat (Triticum aestivum L.) monoculture is conventionally cultivated followed by two to three months of summer fallow in the Loess Plateau. To develop a sustainable cropping system, we conducted a six-year field experiment to investigate the effect of leguminous green manure (LGM) instead of bare fallow on the yield and water use efficiency (WUE) of winter wheat and the soil water balance (SWB) in different precipitation years in a semi-arid region of northwest China. Results confirmed that planting LGM crop consumes soil water in the fallow season can bring varied effects to the subsequent wheat. The effect is positive or neutral when the annual precipitation is adequate, so that there is no significant reduction in the soil water supplied to wheat. If this is not the case, the effect is negative. On average, the LGM crop increased wheat yield and WUE by 13% and 28%, respectively, and had considerable potential for maintaining the SWB (0–200 cm) compared with fallow management. In conclusion, cultivation of the LGM crop is a better option than fallow to improve the productivity and WUE of the next crop and maintain the soil water balance in the normal and wet years in the Loess Plateau.

  1. Water Balance of the San Simon Groundwater Basin, El Salvador, Central America

    NASA Astrophysics Data System (ADS)

    Sullivan, M.; Lopez, D. L.; Matus, A.

    2008-05-01

    The Berlin hydrothermal field in El Salvador, Central America is located in the San Simon River Basin on the northwest slope of the Berlin-Tecapa volcanic complex, in the eastern portion of the country. This hydrothermal field, which has been exploited since 1992, is a liquid-dominated system governed by faults and caldera structures allowing infiltration and transport of meteoric fluids. San Simon River is a tributary of the Lempa River, the largest river in the country. Geophysical studies have found that the Berlin field is composed of three aquifers (Shallow, Intermediate, Deep). Exploitation involves the removal of hot fluids from the geothermal reservoir (deep aquifer) and re-injection of lower temperature fluids. This study analyzes the surficial hydrology and groundwater storage change (since exploitation) in the hydrothermal reservoir to produce a water budget. Field monitoring of springs, fumarolic activity, domestic wells, tributaries to the San Simon River, and meteorological data provide constraints on the hydrology. Springs occur in the system close to fault zones or at contacts between different lithologies. The water balance for the San Simon groundwater basin (July 2004 - June 2005) indicates that 2.51 - 3.46 E7 m3/yr of water are infiltrated to the ground, 1.30 - 1.45E7 m3/yr comprises the overland flow, 5.74 E6 m3/yr form the base flow of the San Simon River, and 1.54 E5 m3/yr is released thru the evaporation of Alegria Lake. The shallow aquifer is affected by pumping of 4.78 E6 m3/yr by the national water company. To complete the water balance of the San Simon Basin, a correlation between the composition of the fumarolic gases and the diffuse flux of soil CO2 was performed. The flux of water released from fumarolic areas was estimated at 1.48 E5 m3/yr. An analysis of the increase in chloride concentration with time in the deep aquifer and the net mass withdrawn from this aquifer allow an estimation of the decrease in storage in the hydrothermal

  2. Botswana water and surface energy balance research program. Part 2: Large scale moisture and passive microwaves

    NASA Technical Reports Server (NTRS)

    Vandegriend, A. A.; Owe, M.; Chang, A. T. C.

    1992-01-01

    The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. The research program consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components are explained in general and activities performed within the passive microwave research component are summarized. The microwave theory is discussed taking into account: soil dielectric constant, emissivity, soil roughness effects, vegetation effects, optical depth, single scattering albedo, and wavelength effects. The study site is described. The soil moisture data and its processing are considered. The relation between observed large scale soil moisture and normalized brightness temperatures is discussed. Vegetation characteristics and inverse modeling of soil emissivity is considered.

  3. Development of EOS-aided procedures for the determination of the water balance of hydrologic budget of a large watershed

    NASA Technical Reports Server (NTRS)

    Congalton, Russell G.; Thomas, Randall W.; Zinke, Paul J.

    1986-01-01

    Work focused on the acquisition of remotely sensed data for the 1985 to 1986 hydrogolic year; continuation of the field measurement program; continued acquisition and construction of passive microwave remote sensing instruments; a compilation of data necessary for an initial water balance computation; and participation with the EOS Simulataneity Team in reviewing the Feather River watershed as a possible site for a simultaneity experiment.

  4. Comparative Analysis of Seepage Losses From Nighttime Water Level Changes and Water Balance Methods

    NASA Astrophysics Data System (ADS)

    Shukla, A.; Shukla, S.; Wu, C.

    2013-12-01

    Several techniques including Darcy's theory of one and two dimensional groundwater flow, seepage meters, and water balance have been used in the past to estimate seepage from impoundments such as reservoirs, ponds, and constructed wetlands. These methods result in varying level of errors in seepage estimates depending on method and biogeophysical setting to which they are applied. In this study, we explore a simple yet effective method of estimating groundwater fluxes for two stormwater impoundments (SIs) and a partially drained wetland located in agricultural areas using diurnal changes in surface water levels inside these systems. Days with no inflow, outflow, and rainfall were selected to minimize the effect of the error associated water balance components on seepage estimation. Difference in water levels between 20:00 hrs and 5:00 hrs was calculated for the selected days. Only nighttime change was considered keeping in mind the fact that evapotranspiration is negligible during night and hence, the change in water levels can be attributed to seepage alone. Seepage from the analysis of night-time change in the water levels was compared to the estimates from the water balance method with seepage being the residual component of the balance. Results show that seepage constitutes a large part of total outflow from the impoundments (29% and 17% for SI1 during 2008-2009 and 2009-2010 respectively, 30% for SI2 during 2009-2010 and seepage was greater than the total surface water outflow from SI2 during 2010-2011). Accuracy of this method varied from 5% to 41% for first and 4% to 29% for the second SI. Considering that errors as high as 100% have been reported with the use of Darcy's approach, the errors from our method are lower. The lower errors combined with ease of application without using the hydraulic conductivity values makes our approach feasible for other similar systems. Improved seepage estimate from the proposed method will result in quantification of

  5. Improving the performance of water balance equation using fuzzy logic approach

    NASA Astrophysics Data System (ADS)

    Khazaei, Bahram; Hosseini, Seyed Mahmood

    2015-05-01

    It is a common practice to conduct the water budget or water balance analysis in a given area within a specified time in order to investigate the balance between the inputs and outputs of the water system. Such an analysis can be used for water management and water allocation in a designated study area. Due to appearance of an error in water balance equation because of difficulty in accurate estimation of its individual components, the main objective of the current paper was to apply a set of fuzzy coefficients to the components of the water balance equation in order to reduce this error. The fuzzy coefficients reflect the uncertainty and imprecision in evaluating each component, and minimize the overall error of the water balance equation. These coefficients are adjusted by an error minimization procedure, based on fuzzy regression concepts and using available recorded data for a given study area within a specified time scale. The adjusted coefficients can effectively estimate the water balance components in the future. In this study, four different models, representing different types of fuzzy coefficients, were considered and used for annual water balance of Azghand catchment in Khorasan Razavi Province, Iran as a case study. Analysis of results showed that all models were effective in reducing water balance error in Azghand catchment. The best model reduced the error up to 79% in terms of mean absolute error compared with error in water balance equation when conventional (with no correction coefficients) water balance analysis was conducted. Moreover, the results indicated that the performance of the proposed fuzzy models was not significantly sensitive to selection of confidence level in data (h) and improved slightly as h increased.

  6. Energy and water balance response of a vegetated wetland to herbicide treatment of invasive Phragmites australis

    NASA Astrophysics Data System (ADS)

    Mykleby, Phillip M.; Lenters, John D.; Cutrell, Gregory J.; Herrman, Kyle S.; Istanbulluoglu, Erkan; Scott, Durelle T.; Twine, Tracy E.; Kucharik, Christopher J.; Awada, Tala; Soylu, Mehmet E.; Dong, Bo

    2016-08-01

    The energy and water balance of a Phragmites australis dominated wetland in south central Nebraska was analyzed to assess consumptive water use and the potential for "water savings" as a result of vegetation eradication via herbicide treatment. Energy balance measurements were made at the field site for two growing seasons (treated and untreated), including observations of net radiation, heat storage, and sensible heat flux, which was measured using a large-aperture scintillometer. Latent heat flux was calculated as a residual of the energy balance, and comparisons were made between the two growing seasons and with model simulations to examine the relative impacts of vegetation removal and climate variability. Observed ET rates dropped by roughly 32% between the two growing seasons, from a mean of 4.4 ± 0.7 mm day-1 in 2009 (with live vegetation) to 3.0 ± 0.8 mm day-1 in 2010 (with dead P. australis). These results are corroborated by the Agro-IBIS model simulations, and the reduction in ET implies a total "water savings" of 245 mm over the course of the growing season. The significant decreases in ET were accompanied by a more-than-doubling of sensible heat flux, as well as a ∼60% increase in heat storage due to decreased LAI. Removal of P. australis was also found to cause measurable changes in the local micrometeorology at the wetland. Consistent with the observed increase in sensible heat flux during 2010, warmer, drier, windier conditions were observed in the dead, P. australis section of the wetland, compared to an undisturbed section of live, native vegetation. Modeling results suggest that the elimination of transpiration in 2010 was partially offset by an increase in surface evaporation, thereby reducing the subsequent water savings by roughly 60%. Thus, the impact of vegetation removal depends on the local climate, depth to groundwater, and management decisions related to regrowth of vegetation.

  7. Storing and sharing water in sand rivers: a water balance modelling approach

    NASA Astrophysics Data System (ADS)

    Love, D.; van der Zaag, P.; Uhlenbrook, S.

    2009-04-01

    Sand rivers and sand dams offer an alternative to conventional surface water reservoirs for storage. The alluvial aquifers that make up the beds of sand rivers can store water with minimal evaporation (extinction depth is 0.9 m) and natural filtration. The alluvial aquifers of the Mzingwane Catchment are the most extensive of any tributaries in the Limpopo Basin. The lower Mzingwane aquifer, which is currently underutilised, is recharged by managed releases from Zhovhe Dam (capacity 133 Mm3). The volume of water released annually is only twice the size of evaporation losses from the dam; the latter representing nearly one third of the dam's storage capacity. The Lower Mzingwane valley currently support commercial agro-businesses (1,750 ha irrigation) and four smallholder irrigation schemes (400 ha with provision for a further 1,200 ha). In order to support planning for optimising water use and storage over evaporation and to provide for more equitable water allocation, the spreadsheet-based balance model WAFLEX was used. It is a simple and userfriendly model, ideal for use by institutions such as the water management authorities in Zimbabwe which are challenged by capacity shortfalls and inadequate data. In this study, WAFLEX, which is normally used for accounting the surface water balance, is adapted to incorporate alluvial aquifers into the water balance, including recharge, baseflow and groundwater flows. Results of the WAFLEX modelling suggest that there is surplus water in the lower Mzingwane system, and thus there should not be any water conflicts. Through more frequent timing of releases from the dam and maintaining the alluvial aquifers permanently saturated, less evaporation losses will occur in the system and the water resources can be better shared to provide more irrigation water for smallholder farmers in the highly resource-poor communal lands along the river. Sand dams are needed to augment the aquifer storage system and improve access to water. An

  8. Mapping crop evapotranspiration by integrating vegetation indices into a soil water balance model

    NASA Astrophysics Data System (ADS)

    Consoli, Simona; Vanella, Daniela

    2015-04-01

    The approach combines the basal crop coefficient (Kcb) derived from vegetation indices (VIs) with the daily soil water balance, as proposed in the FAO-56 paper, to estimate daily crop evapotranspiration (ETc) rates of orange trees. The reliability of the approach to detect water stress was also assessed. VIs were simultaneously retrieved from WorldView-2 imagery and hyper-spectral data collected in the field for comparison. ETc estimated were analysed at the light of independent measurements of the same fluxes by an eddy covariance (EC) system located in the study area. The soil water depletion in the root zone of the crop simulated by the model was also validated by using an in situ soil water monitoring. Average overestimate of daily ETc of 6% was obtained from the proposed approach with respect to EC measurements, evidencing a quite satisfactory agreement between data. The model also detected several periods of light stress for the crop under study, corresponding to an increase of the root zone water deficit matching quite well the in situ soil water monitoring. The overall outcomes of this study showed that the FAO-56 approach with remote sensing-derived basal crop coefficient can have the potential to be applied for estimating crop water requirements and enhancing water management strategies in agricultural contexts.

  9. IMPLICATIONS OF CLIMATE CHANGE FOR THE WATER BALANCE OF THE COLUMBIA RIVER BASIN, USA

    EPA Science Inventory

    Global climate change will affect the terrestrial biosphere primarily through changes in regional energy and water balance. hanges in soil moisture and evapotranspiration will particularly affect water and forest resources. xisting spatially lumped hydrologic models are not adequ...

  10. The springs of Lake Pátzcuaro: chemistry, salt-balance, and implications for the water balance of the lake

    USGS Publications Warehouse

    Bischoff, James L.; Israde-Alcántara, Isabel; Garduno-Monroy, Victor H.; Shanks, Wayne C., III

    2004-01-01

    Lake Pa??tzcuaro, the center of the ancient Tarascan civilization located in the Mexican altiplano west of the city of Morelia, has neither river input nor outflow. The relatively constant lake-salinity over the past centuries indicates the lake is in chemical steady state. Springs of the south shore constitute the primary visible input to the lake, so influx and discharge must be via sub-lacustrine ground water. The authors report on the chemistry and stable isotope composition of the springs, deeming them representative of ground-water input. The springs are dominated by Ca, Mg and Na, whereas the lake is dominated by Na. Combining these results with previously published precipitation/rainfall measurements on the lake, the authors calculate the chemical evolution from spring water to lake water, and also calculate a salt balance of the ground-water-lake system. Comparing Cl and ??18O compositions in the springs and lake water indicates that 75-80% of the spring water is lost evaporatively during evolution toward lake composition. During evaporation Ca and Mg are lost from the water by carbonate precipitation. Each liter of spring water discharging into the lake precipitates about 18.7 mg of CaCO3. Salt balance calculations indicate that ground water input to the lake is 85.9??106 m3/a and ground water discharge from the lake is 23.0??106 m3/a. Thus, the discharge is about 27% of the input, with the rest balanced by evaporation. A calculation of time to reach steady-state ab initio indicates that the Cl concentration of the present day lake would be reached in about 150 a. ?? 2004 Elsevier Ltd. All rights reserved.

  11. Ultraendurance cycling in a hot environment: thirst, fluid consumption, and water balance.

    PubMed

    Armstrong, Lawrence E; Johnson, Evan C; McKenzie, Amy L; Ellis, Lindsay A; Williamson, Keith H

    2015-04-01

    The purpose of this field investigation was to identify and clarify factors that may be used by strength and conditioning professionals to help athletes drink adequately but not excessively during endurance exercise. A universal method to accomplish this goal does not exist because the components of water balance (i.e., sweat rate, fluid consumed) are different for each athlete and endurance events differ greatly. Twenty-six male cyclists (mean ± SD; age, 41 ± 8 years; height, 177 ± 7 cm; body mass, 81.85 ± 8.95 kg) completed a summer 164-km road cycling event in 7.0 ± 2.1 hours (range, 4.5-10.4 hours). Thirst ratings, fluid consumed, indices of hydration status, and body water balance (ingested fluid volume - [urine excreted + sweat loss]) were the primary outcome variables. Measurements were taken before the event, at designated aid stations on the course (52, 97, and 136 km), and at the finish line. Body water balance during exercise was not significantly correlated with exercise time on the course, height, body mass, or body mass index. Thirst ratings were not significantly correlated with any variable. We also observed a wide range of total sweat losses (4.9-12.7 L) and total fluid intakes (2.1-10.5 L) during this ultraendurance event. Therefore, we recommend that strength and conditioning professionals develop an individualized drinking plan for each athlete, by calculating sweat rate (milliliter per hour) on the basis of body mass change (in kilograms), during field simulations of competition. PMID:25559907

  12. Climate, interseasonal storage of soil water, and the annual water balance

    USGS Publications Warehouse

    Milly, P.C.D.

    1994-01-01

    The effects of annual totals and seasonal variations of precipitation and potential evaporation on the annual water balance are explored. It is assumed that the only other factor of significance to annual water balance is a simple process of water storage, and that the relevant storage capacity is the plant-available water-holding capacity of the soil. Under the assumption that precipitation and potential evaporation vary sinusoidally through the year, it is possible to derive an analytic solution of the storage problem, and this yields an expression for the fraction of precipitation that evaporates (and the fraction that runs off) as a function of three dimensionless numbers: the ratio of annual potential evaporation to annual precipitation (index of dryness); an index of the seasonality of the difference between precipitation and potential evaporation; and the ratio of plant-available water-holding capacity to annual precipitation. The solution is applied to the area of the United States east of 105??W, using published information on precipitation, potential evaporation, and plant-available water-holding capacity as inputs, and using an independent analysis of observed river runoff for model evaluation. The model generates an areal mean annual runoff of only 187 mm, which is about 30% less than the observed runoff (263 mm). The discrepancy is suggestive of the importance of runoff-generating mechanisms neglected in the model. These include intraseasonal variability (storminess) of precipitation, spatial variability of storage capacity, and finite infiltration capacity of land. ?? 1994.

  13. Infiltration and water balance modeling along a toposequence in a rubber tree plantation of NE Thailand

    NASA Astrophysics Data System (ADS)

    Hammecker, Claude; Seltacho, Siwaporn; Suvanang, Nopmanee; Do, Frederic; Angulo-Jaramillo, Rafael

    2015-04-01

    Northeast of Thailand, is a plateau at 200 m AMSL with a typical undulating landscape. Traditionally the lowlands were dedicated to paddy fields and the uplands covered by Dipterocarpus forest. However development of cash crops during the last decades has led to intensive land clearing in the uplands and to modifications at a regional scale of the water balance in the critical zone with increasing runoff and soil erosion. Recent international demand increase for natural rubber motivated many local farmers to shift from these cash crops towards rubber-tree (Heva Brasiliensis) plantations. However these land use changes have been undertaken without considering the climatic and edaphic specificity of the region, which are not well adapted to the growth of rubber tree (rainfall lower than recommended and sandy soils with low fertility). Therefore, in order to assess and try to predict the environmental consequences (water resources, water-table, ..) of the development of rubber tree plantations in this area, a small watershed in the region ok Khon Kaen has been selected to follow the infiltration and to monitor the different components of the water balance along a toposequence. A six years monitoring of the main components of water balance along a toposequence associated to numerical simulation were used to quantify and try to forecast the evolution of the water use and water resources. Unsaturated soil properties were determined at different depths, in various positions along the toposequence. Experimental results supported by modeling of 2D water flow with HYDRUS3D show clearly that infiltration is blocked by a clayey layer on top of the bedrock and conditioned the occurrence of a perched watertable during the rainy seasons. Most of the soil water flow was found to be directed laterally during the rainy season. The deep groundwater was found to be fed from the lower part of toposequence in the thalweg. The transpiration rate measured on the trees at this stage of

  14. Student Misconceptions in Writing Balanced Equations for Dissolving Ionic Compounds in Water

    ERIC Educational Resources Information Center

    Naah, Basil M.; Sanger, Michael J.

    2012-01-01

    The goal of this study was to identify student misconceptions and difficulties in writing symbolic-level balanced equations for dissolving ionic compounds in water. A sample of 105 college students were asked to provide balanced equations for dissolving four ionic compounds in water. Another 37 college students participated in semi-structured…

  15. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  16. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  17. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  18. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  19. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  20. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  1. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  2. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  3. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  4. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limitations for coal mining promulgated by the U.S. Environmental Protection Agency set forth in 40 CFR part... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Hydrologic balance: Water quality standards and... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  5. A Coupled Remote Sensing and Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration from Irrigated Fields

    PubMed Central

    Senay, Gabriel B.; Budde, Michael; Verdin, James P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250-m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  6. A coupled remote sensing and simplified surface energy balance approach to estimate actual evapotranspiration from irrigated fields

    USGS Publications Warehouse

    Senay, G.B.; Budde, M.; Verdin, J.P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  7. Impact of climatic noise on global estimates of terrestrial water balance components

    NASA Astrophysics Data System (ADS)

    Nasonova, Olga; Gusev, Yeugeniy; Semenov, Vladimir; Kovalev, Evgeny

    2016-04-01

    Estimates of water balance components performed by different authors in climate impact studies are characterized by a large scatter or uncertainty associated, in particular, with application of different meteorological forcing data (simulated by climate models), different estimates of model parameters, and different hydrological models. In the present work, the objective uncertainty, which cannot be reduced by means of better physical description of the processes under study or by means of improvement of the quality of input data for model simulations, and which is an internal feature of the atmosphere - hydrosphere - land surface system, is considered. This uncertainty is caused by a chaotic character of atmospheric processes (i.e. by so-called climatic noise), their instability with respect to small errors in determination of initial conditions for modeling the evolution of meteorological variables. Our study is devoted to investigating the impact of climatic noise on the estimates of terrestrial water balance components (precipitation, runoff and evapotranspiration) on a global scale. To achieve the effect of climatic noise 45 simulations were performed by the atmospheric general circulation model ECHAM5 under identical lower boundary conditions (including sea surface temperatures and sea ice concentrations) and constant external forcing parameters. The only differences between the simulations were initial conditions of the atmosphere. Meteorological fields simulated by ECHAM5 for the period of 1979-2012 were used as forcing data (with 6-hour temporal resolution and one-degree spatial one) by the land surface model Soil Water - Atmosphere - Plants (SWAP) for hydrological simulations on a global scale. As a result, 45-member ensemble of the water balance components for the land surface of the Earth excluding Antarctica was obtained. Analysis of the obtained results allowed us to estimate the lowest level of uncertainty which can be achieved in climate impact

  8. Modeling plant competition for soil water balance in Water-limited Mediterranean Ecosystems

    NASA Astrophysics Data System (ADS)

    Cortis, C.; Montaldo, N.

    2009-12-01

    In heterogeneous ecosystems, such Mediterranean ecosystems, contrasting plant functional types (PFTs, e.g., grass and woody vegetation) compete for the water use. In these complex ecosystems current modeling approaches need to be improved due to a general lack of knowledge about the relationship between ET and the plant survival strategies for the different PFTs under water stress. Indeed, still unsolved questions are: how the PFTs (in particular the root systems) compete for the water use, the impact of this competition on the water balance terms, and the role of the soil type and soil depth in this competition. For this reasons an elaborated coupled Vegetation dynamic model (VDM) - land surface model (LSM) model able to also predict root distribution of competing plant systems is developed. The transport of vertical water flow in the unsaturated soil is modelled through a Richards’ equation based model. The water extraction (sink) term is considered as the root water uptake. Two VDMs predict vegetation dynamics, including spatial and temporal distribution/evolution of the root systems in the soil of two competing species (grass and woody vegetation). An innovative method for solving the unlinear system of predicting equations is proposed. The coupled model is able to predict soil and root water potential of the two competing plant species. The model is tested for the Orroli case study, situated in the mid-west of Sardinia within the Flumendosa river watershed. The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and coark oaks, different shrubs and herbaceous species. In particular two contrasting plant functional types (grass and woody vegetation) have been included. The model well predict the soil moisture and vegetation dynamics for the case study, and significantly different root potentials are predicted for the two PFTs, highlighting the root competition for the water use. The soil depth is low in the case

  9. ANALYSIS OF WATER AND ENERGY FLUXES USING SATELLITE, ENERGY BALANCE MODELING AND OBSERVATIONS (Invited)

    NASA Astrophysics Data System (ADS)

    Irmak, A.

    2009-12-01

    Surface energy fluxes, including net radiation (Rn), sensible heat (H), latent heat (LE), and soil heat flux (G) are critical in surface energy balance of any terrain or landscapes. Estimation or measurement of these energy fluxes is important for completing the water balance in terrestrial ecosystems, and therefore accurately predicting the effects of global climate and land use change. The objectives of this study were to (1) use METRICtm (Mapping Evapotranspiration at high Resolution using Internalized Calibration) model for estimating land surface energy fluxes in Nebraska (NE) by utilizing satellite remote sensing data, (2) identify model bias in energy balance components compared with measurements from Bowen Ratio Energy Balance System (BREBS) in a subsurface drip-irrigated maize field in South-central Nebraska, and (3) understand the partitioning of available energy into latent heat for corn and soybean cropping systems at large scale. A total of 15 Landsat images were processed to estimate instantaneous surface energy fluxes at Landsat overpasses with METRIC model. Results showed that the model predictions of the surface energy fluxes and daily evapotranspiration were correlated well with the BREBS measurements. There is a need, however, to test the performance of the model with in-situ observations in other locations with different dataset before utilizing it for crucial water regulatory and policy decisions. The METRICtm approach illustrated how an ‘off-the-shelf’ model can be applied operationally over a significant time period and how that model behaves. The findings makes considerable contribution to our understanding of estimating land surface energy fluxes using remote sensing approach and experimentally describes the operational characteristics of METRICtm and presents its limitations.

  10. Managing field water supply to increase water use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field water supply (FWS) represents the three sources of water that a crop can use for evapotranspiration (ET), and consists of available soil water at planting (ASWP), rainfall, and irrigation. Because it integrates all sources of water available to a crop, it impacts crop water production function...

  11. Soil water samplers in ion balance studies on acidic forest soils

    SciTech Connect

    Rasmussen, L.; Joergensen, P.; Kruse, S.

    1986-04-01

    During the last years an increasing consciousness has appeared of the injurious effects of acid rain on the forest ecosystems both in Europe and North America. At several localities ion balance studies have been implemented in order to evaluate the impact of the atmospheric deposition of acidic substances and heavy metals on the forest ecosystem. In many localities the leaching of material to the ground water or output from the ecosystem has to be determined by means of tensiometer measurements and soil water sampling. Many different soil water samplers are available on the market and they show useful applicability under the given circumstances. But in many cases soil water samples taken with different equipment give incommensurable results leading to differing explanations of the effects of acid precipitation on elements and their cycling in the ecosystem. The purpose of the present study is twofold. Firstly, the sorption characteristics of different types of soil water samplers are examined under acidic soil conditions both by installation in the field and by laboratory experiments. Secondly, a new method is introduced for current and constant soil water sampling under varying soil suctions in the unsaturated zone.

  12. A method for simulating transient ground-water recharge in deep water-table settings in central Florida by using a simple water-balance/transfer-function model

    USGS Publications Warehouse

    O'Reilly, Andrew M.

    2004-01-01

    A relatively simple method is needed that provides estimates of transient ground-water recharge in deep water-table settings that can be incorporated into other hydrologic models. Deep water-table settings are areas where the water table is below the reach of plant roots and virtually all water that is not lost to surface runoff, evaporation at land surface, or evapotranspiration in the root zone eventually becomes ground-water recharge. Areas in central Florida with a deep water table generally are high recharge areas; consequently, simulation of recharge in these areas is of particular interest to water-resource managers. Yet the complexities of meteorological variations and unsaturated flow processes make it difficult to estimate short-term recharge rates, thereby confounding calibration and predictive use of transient hydrologic models. A simple water-balance/transfer-function (WBTF) model was developed for simulating transient ground-water recharge in deep water-table settings. The WBTF model represents a one-dimensional column from the top of the vegetative canopy to the water table and consists of two components: (1) a water-balance module that simulates the water storage capacity of the vegetative canopy and root zone; and (2) a transfer-function module that simulates the traveltime of water as it percolates from the bottom of the root zone to the water table. Data requirements include two time series for the period of interest?precipitation (or precipitation minus surface runoff, if surface runoff is not negligible) and evapotranspiration?and values for five parameters that represent water storage capacity or soil-drainage characteristics. A limiting assumption of the WBTF model is that the percolation of water below the root zone is a linear process. That is, percolating water is assumed to have the same traveltime characteristics, experiencing the same delay and attenuation, as it moves through the unsaturated zone. This assumption is more accurate if

  13. Uncertainty of canal seepage losses estimated using flowing water balance with acoustic Doppler devices

    NASA Astrophysics Data System (ADS)

    Martin, Chad A.; Gates, Timothy K.

    2014-09-01

    presented for conducting field water balance tests to recognize and reduce uncertainty in canal seepage estimates.

  14. SWB-A modified Thornthwaite-Mather Soil-Water-Balance code for estimating groundwater recharge

    USGS Publications Warehouse

    Westenbroek, S.M.; Kelson, V.A.; Dripps, W.R.; Hunt, R.J.; Bradbury, K.R.

    2010-01-01

    A Soil-Water-Balance (SWB) computer code has been developed to calculate spatial and temporal variations in groundwater recharge. The SWB model calculates recharge by use of commonly available geographic information system (GIS) data layers in combination with tabular climatological data. The code is based on a modified Thornthwaite-Mather soil-water-balance approach, with components of the soil-water balance calculated at a daily timestep. Recharge calculations are made on a rectangular grid of computational elements that may be easily imported into a regional groundwater-flow model. Recharge estimates calculated by the code may be output as daily, monthly, or annual values.

  15. Surface water management: a user's guide to calculate a water balance using the CREAMS model

    SciTech Connect

    Lane, L.J.

    1984-11-01

    The hydrologic component of the CREAMS model is described and discussed in terms of calculating a surface water balance for shallow land burial systems used for waste disposal. Parameter estimates and estimation procedures are presented in detail in the form of a user's guide. Use of the model is illustrated with three examples based on analysis of data from Los Alamos, New Mexico and Rock Valley, Nevada. Use of the model in design of trench caps for shallow land burial systems is illustrated with the example applications at Los Alamos.

  16. Integration of vegetation indices into a water balance model to estimate evapotranspiration of wheat and corn

    NASA Astrophysics Data System (ADS)

    Padilla, F. L. M.; González-Dugo, M. P.; Gavilán, P.; Domínguez, J.

    2011-04-01

    Vegetation indices (VIs) have been traditionally used for quantitative monitoring of vegetation. Remotely sensed radiometric measurements of visible and infrared solar energy, which is reflected or emitted by plant canopies, can be used to obtain rapid, non-destructive estimates of certain canopy attributes and parameters. One parameter of special interest for water management applications, is the crop coefficient employed by the FAO-56 model to derive actual crop evapotranspiration (ET). The aim of this study was to evaluate a methodology that combines the basal crop coefficient derived from VIs with a daily soil water balance in the root zone to estimate daily evapotranspiration rates for corn and wheat crops at field scale. The ability of the model to trace water stress in these crops was also assessed. Vegetation indices were first retrieved from field hand-held radiometer measurements and then from Landsat 5 and 7 satellite images. The results of the model were validated using two independent measurement systems for ET and regular soil moisture monitoring, in order to evaluate the behavior of the soil and atmosphere components of the model. ET estimates were compared with latent heat flux measured by an eddy covariance system and with weighing lysimeter measurements. Average overestimates of daily ET of 8 and 11% were obtained for corn and wheat, respectively, with good agreement between the estimated and measured root-zone water deficit for both crops when field radiometry was employed. When the satellite sensor data replaced the field radiometry data the overestimation figures slightly changed to 9 and 6% for the same two crops. The model was also used to monitor the water stress during the 2009 growing season, detecting several periods of water stress in both crops. Some of these stresses occurred during stages like grain filling, when the water stress is know to have a negative effect on yield. This fact could explain the lower yield reached compared to

  17. Integration of vegetation indices into a water balance model to estimate evapotranspiration of wheat and corn

    NASA Astrophysics Data System (ADS)

    Padilla, F. L. M.; González-Dugo, M. P.; Gavilán, P.; Domínguez, J.

    2010-10-01

    Vegetation indices (VIs) have been traditionally used for quantitative monitoring of vegetation. Remotely sensed radiometric measurements of visible and infrared solar energy, which is reflected or emitted by plant canopies, can be used to obtain rapid, non-destructive estimates of certain canopy attributes and parameters. One parameter of special interest for water management applications, is the crop coefficient employed by the FAO-56 model to derive actual crop evapotranspiration (ET). The aim of this study was to evaluate a methodology that combines the basal crop coefficient derived from VIs with a daily soil water balance in the root zone to estimate daily evapotranspiration rates for corn and wheat crops at field scale. The ability of the model to trace water stress in these crops was also assessed. Vegetation indices were first retrieved from field hand-held radiometer measurements and then from Landsat 5 and 7 satellite images. The results of the model were validated using two independent measurement systems for ET and regular soil moisture monitoring, in order to evaluate the behavior of the soil and atmosphere components of the model. ET estimates were compared with latent heat flux measured by an eddy covariance system and with weighing lysimeter measurements. Average overestimates of daily ET of 8 and 11% were obtained for corn and wheat, respectively, with good agreement between the estimated and measured root-zone water deficit for both crops when field radiometry was employed. Satellite remote-sensing inputs overestimated ET by 4 to 9%, showing a non-significant lost of accuracy when the satellite sensor data replaced the field radiometry data. The model was also used to monitor the water stress during the 2009 growing season, detecting several periods of water stress in both crops. Some of these stresses occurred during stages like grain filling, when the water stress is know to have a negative effect on yield. This fact could explain the lower

  18. Combining the soilwater balance and water-level fluctuation methods to estimate natural groundwater recharge: Practical aspects

    USGS Publications Warehouse

    Sophocleous, M.A.

    1991-01-01

    A relatively simple and practical approach for calculating groundwater recharge in semiarid plain environments with a relatively shallow water table, such as the Kansas Prairies, is outlined. Major uncertainties in the Darcian, water balance, and groundwater fluctuation analysis approaches are outlined, and a combination methodology for reducing some of the uncertainties is proposed. By combining a storm-based soilwater balance (lasting several days) with the resulting water table rise, effective storativity values of the region near the water table are obtained. This combination method is termed the 'hybrid water-fluctuation method'. Using a simple average of several such estimates results in a site-calibrated effective storativity value that can be used to translate each major water-table rise tied to a specific storm period into a corresponding amount of groundwater recharge. Examples of soilwater balance and water-level fluctuation analyses based on field-measured data from Kansas show that the proposed methodology gives better and more reliable results than either of the two well-established approaches used singly. ?? 1991.

  19. Modeling the water and energy balance of vegetated areas with snow accumulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability to quantify soil–atmosphere water and energy exchange is important in understanding agricultural and natural ecosystems, as well as the earth’s climate. We developed a one-dimensional vertical model that calculates solar radiation, canopy energy balance, surface energy balance, snowpack ...

  20. Balance in Training for Latin American Water and Wastewater Utilities

    ERIC Educational Resources Information Center

    Carefoot, Neil F.

    1977-01-01

    Using a Peru case study, this article examines the problem of training imbalance for water and wastewater operators. Guidelines towards achieving adequate training for all water and wastewater personnel are suggested. (Author/MA)

  1. GRACE Time-Variable Gravity Field Recovery Using an Improved Energy Balance Formalism

    NASA Astrophysics Data System (ADS)

    Shang, Kun

    Earth's gravity is continuously varying with respect to time due primarily to mass transports within the Earth system and external gravitational forcing. A new formalism based on energy conservation principle for time-variable gravity field recovery using satellite gravimetry has been developed and yields more accurate estimation of in-situ geopotential difference observables using K-Band Ranging (KBR) measurements from the Gravity Recovery and Climate Experiment (GRACE) twin-satellite mission. The new approach can preserve more time-variable gravity information sensed by KBR range-rate measurements and reduce orbit error as compared to previous energy balance studies. Results based on analysis of more than 10 years of GRACE data indicate that the estimated geopotential differences agree well with the predicted values from official Level 2 solutions: with much higher correlation of 0.9, as compared to 0.5-0.8 reported by previous energy balance studies. This study demonstrates that the new approach is more flexible for both global and regional temporal gravity recovery, leading to the first independent GRACE monthly solution series based on energy conservation principle, which is comparable to the results from different approach. The developed formalism is applicable to the general case of low-low satellite-to-satellite radiometric or laser interferometric tracking measurements, such as GRACE Follow-on or other Next Generation Gravity Field missions, for efficient retrieval and studies of Earth's mass transport evolutions. The regional gravity analysis over Greenland reveals that a substantially higher temporal resolution is achievable at 10 or 11-day interval from GRACE data, as compared to the official monthly solutions, but without the compromise of spatial resolution, nor the need to use regularization or post-processing. Studies of the terrestrial and ground water storage change over North China Plain show high correlation in sub-monthly scale, among the 11

  2. Carbon Balance in an Irrigated Corn Field after Inorganic Fertilizer or Manure Application

    NASA Astrophysics Data System (ADS)

    Lentz, R. D.; Lehrsch, G. A.

    2014-12-01

    Little is known about inorganic fertilizer or manure effects on organic carbon (OC) and inorganic C (IC) losses from a furrow irrigated field, particularly in the context of other system C gains or losses. In 2003 and 2004, we measured dissolved organic and inorganic C (DOC, DIC), particulate OC and IC (POC, PIC) concentrations in irrigation inflow, runoff, and percolation waters (6-7 irrigations/y); C inputs from soil amendments and crop biomass; harvested C; and gaseous C emissions from field plots cropped to silage corn (Zea mays L.) in southern Idaho. Annual treatments included: (M) 13 (y 1) and 34 Mg/ha (y 2) stockpiled dairy manure; (F) 78 (yr 1) and 195 kg N/ha (y 2) inorganic N fertilizer; or (NA) no amendment--control. The mean annual total C input into M plots averaged 16.1 Mg/ha, 1.4-times greater than that for NA (11.5 Mg/ha) or F (11.1 Mg/ha), while total C outputs for the three treatments were similar, averaging 11.8 Mg/ha. Thus, the manure plots ended each growing season with an average net gain of 3.8 Mg C/ha (a positive net C flux), while the control (-0.5 Mg C/ha) and fertilizer (-0.4 Mg C/ha) treatments finished the season with a net C loss. Atmospheric CO2 incorporated into the crop biomass contributed 96% of the mean annual C input to NA and F plots but only 68% to M plots. We conclude that nutrient amendments substantially influence the short-term carbon balance of our furrow-irrigated system. Amendments had both direct and indirect influences on individual C components, such as the losses of DIC and POC in runoff and DOC in percolation water, producing temporally complex outcomes which may depend on environmental conditions external to the field.

  3. Beyond annual streamflow reconstructions for the Upper Colorado River Basin: A paleo-water-balance approach

    NASA Astrophysics Data System (ADS)

    Gangopadhyay, Subhrendu; McCabe, Gregory J.; Woodhouse, Connie A.

    2015-12-01

    In this paper, we present a methodology to use annual tree-ring chronologies and a monthly water balance model to generate annual reconstructions of water balance variables (e.g., potential evapotranspiration (PET), actual evapotranspiration (AET), snow water equivalent (SWE), soil moisture storage (SMS), and runoff (R)). The method involves resampling monthly temperature and precipitation from the instrumental record directed by variability indicated by the paleoclimate record. The generated time series of monthly temperature and precipitation are subsequently used as inputs to a monthly water balance model. The methodology is applied to the Upper Colorado River Basin, and results indicate that the methodology reliably simulates water-year runoff, maximum snow water equivalent, and seasonal soil moisture storage for the instrumental period. As a final application, the methodology is used to produce time series of PET, AET, SWE, SMS, and R for the 1404-1905 period for the Upper Colorado River Basin.

  4. Role of vegetation cover on soil water balance in two Mediterranean areas: semiarid and dry at southeastern of Spain.

    NASA Astrophysics Data System (ADS)

    Manrique, Àngela; Ruiz, Samantha; Chirino, Esteban; Bellot, Juan

    2014-05-01

    Water is a limited resource in the semiarid areas, which affects both, the population services, the economic growth, like the natural ecosystems stability. In this context, an accurate knowledge of soil water balance and role of the vegetation cover contribute to improve the management of resources water and forest. These studies are increasingly important, if we consider the latest Assessment Reports of the Intergovernmental Panel on Climate Change. In this paper the main objectives were focused on:(1)To determine the soil water balance on two different climatic conditions, semiarid and dry climate and(2) Assess the effect of vegetation (structure and cover) on soil water balance under the studied climatic conditions. For this purpose we used HYDROBAL ecohydrological model, which calculates at a daily resolution the water flows through of the vegetation canopy, estimates daily soil moisture and predicts deep drainage from the unsaturated soil layer into the aquifer. In order to achieve these objectives, we have selected two sites in the south-eastern of Spain, on soils calcareous and different climatic conditions. Ventós site in a semiarid Mediterranean area and Confrides site in a dry Mediterranean area, with 303 and 611 mm of annual precipitation respectively. Both sites, the predominant vegetation are afforestations with Pinus halepensis on dry grasslands with some patches of thorn shrublands and dwarf scrubs; but it show difference on trees density, cover and height of pines.Soil water balance was determined in each site using HYDROBAL ecohydrological model on one hydrological year (October 2012 and September 2013).Model inputs include climatic variables (daily rainfall and temperature), as well as soil and vegetation characteristics (soil field capacity, soil wilting point, initial soil water content and vegetation cover index). Model outputs are interception, net rainfall, runoff, soil water reserves, actual evapotranspiration, direct percolation, and deep

  5. Ethical issues in field research: balancing competing values.

    PubMed

    O'Neill, P

    1990-04-01

    An ethical issue becomes a dilemma when the psychologist is pulled in different directions by competing values. This paper will focus on the conflict between experimental and ethical values inherent in field research. The problem has special significance in community psychology, which gives priority to studying, in natural settings, those affected by social problems. An example is given of research that required observation of family interaction in the homes of convicted child abusers. The case demonstrates that the value of ecological validity often conflicts with the need to protect privacy and obtain uncoerced consent. Other ethical constraints, including the duty to report lawbreaking and to protect the public from harm, may threaten research validity. PMID:16977736

  6. Calibration and Validation of The Soil Water Balance Model Wave For Forest Stands In Flanders: 1. Experimental Setup

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Minnaert, M.; Meiresonne, L.; van Slycken, J.; Lust, N.; Muys, B.; Feyen, J.

    Knowledge on hydrology and particularly on water use in forest ecosystems is rather scarce in Flanders. In order to assess the impact of forests in catchment hydrology, a model approach is required based on available or easily measurable parameters on me- teorology, forest patrimonium and soil cover. A pragmatic approach to calculate water use by forests is to implement a soil water balance model, which enables a reasonable estimate of the evapotranspiration (ET) despite of the fragmented forest, and therefore the strong boundary effects, typically for Flanders. The scientific objectives of this project are multiple: the calibration (i) and validation (ii) of the water balance model WAVE (Water and Agrochemicals in soil, crop and Vadose Environment) to calculate indirectly evapotranspiration of forests (for oak, beech, ash, poplar and pine) on 17 in- tensely and extensively sampled plots. Verification of the evapotranspiration from the WAVE-output with sap-flow measurements (iii). Comparison of evapotranspiration of forests to that of pasture and cropland will also be made (iv). Measurements of rainfall, throughfall, stemflow, capillary rise from the groundwater table (possibly recharge), percolation and changes in soil water content are conducted on weekly base, except for winter time (every two weeks). From these water balance terms the forest evapo- transpiration is derived. The Leaf-Area-Index was gained using hemispherical canopy images. This parameter is used for determining the soil evaporation and tree transpi- ration component from the simulated evaptranspiration. Sap-flow measurements are gathered using the Heat Field Deformation Method (Cermàk and Nadezhdina, 1998) in four plots (2 pine stands, popular, beech/oak). The preliminary results of the cal- ibration and validation of the soil water balance model WAVE for forest stands in Flanders are shown in part 2.

  7. Energy balance closure on a winter wheat stand: comparing the eddy covariance technique with the soil water balance method

    NASA Astrophysics Data System (ADS)

    Imukova, K.; Ingwersen, J.; Hevart, M.; Streck, T.

    2016-01-01

    The energy balance of eddy covariance (EC) flux data is typically not closed. The nature of the gap is usually not known, which hampers using EC data to parameterize and test models. In the present study we cross-checked the evapotranspiration data obtained with the EC method (ETEC) against ET rates measured with the soil water balance method (ETWB) at winter wheat stands in southwest Germany. During the growing seasons 2012 and 2013, we continuously measured, in a half-hourly resolution, latent heat (LE) and sensible (H) heat fluxes using the EC technique. Measured fluxes were adjusted with either the Bowen-ratio (BR), H or LE post-closure method. ETWB was estimated based on rainfall, seepage and soil water storage measurements. The soil water storage term was determined at sixteen locations within the footprint of an EC station, by measuring the soil water content down to a soil depth of 1.5 m. In the second year, the volumetric soil water content was additionally continuously measured in 15 min resolution in 10 cm intervals down to 90 cm depth with sixteen capacitance soil moisture sensors. During the 2012 growing season, the H post-closed LE flux data (ETEC = 3.4 ± 0.6 mm day-1) corresponded closest with the result of the WB method (3.3 ± 0.3 mm day-1). ETEC adjusted by the BR (4.1 ± 0.6 mm day-1) or LE (4.9 ± 0.9 mm day-1) post-closure method were higher than the ETWB by 24 and 48 %, respectively. In 2013, ETWB was in best agreement with ETEC adjusted with the H post-closure method during the periods with low amount of rain and seepage. During these periods the BR and LE post-closure methods overestimated ET by about 46 and 70 %, respectively. During a period with high and frequent rainfalls, ETWB was in-between ETEC adjusted by H and BR post-closure methods. We conclude that, at most observation periods on our site, LE is not a major component of the energy balance gap. Our results indicate that the energy balance gap is made up by

  8. Resilience Through Disturbance: Effects of Wildfire on Vegetation and Water Balance in the Sierra Nevadas

    NASA Astrophysics Data System (ADS)

    Boisrame, G. F. S.; Thompson, S. E.; Stephens, S.; Collins, B.; Tague, N.

    2015-12-01

    A century of fire suppression in the Western United States has drastically altered the historically fire-adapated ecology in California's Sierra Nevada Mountains. Fire suppression is understood to have increased the forest cover, as well as the stem density, canopy cover and water demand of montane forests, reducing resilience of the forests to drought, and increasing the risk of catastrophic fire by drying the landscape and increasing fuel loads. The potential to reverse these trends by re-introducing fire into the Sierra Nevada is highly promising, but the likely effects on vegetation structure and water balance are poorly quantified. The Illilouette Creek Basin in Yosemite National Park represents a unique experiment in the Sierra Nevada, in which managers have moved from fire suppression to allowing a near-natural fire regime to prevail since 1972. Changes in vegetation structure in the Illilouette since the restoration of natural burning provides a unique opportunity to examine how frequent, mixed severity fires can reshape the Sierra Nevada landscape. We characterize these changes from 1969 to the present using a combination of Landsat products and high-resolution aerial imagery. We describe how the landscape structure has changed in terms of vegetation composition and its spatial organization, and explore the drivers of different post-fire vegetation type transitions (e.g. forest to shrubland vs. forest to meadow). By upscaling field data using vegetation maps and Landsat wetness indices, we explore how these vegetation transitions have impacted the water balance of the Illilouette Creek Basin, potentially increasing its resilience in the face of drought, climate change, and catastrophic fire. In a region that is adapted to frequent disturbance from fire, this work helps us understand how allowing such natural disturbances to take place can increase the sustainability of diverse landscapes in the long term.

  9. On the Capabilities of Using AIRSAR Data in Surface Energy/Water Balance Studies

    NASA Technical Reports Server (NTRS)

    Moreno, Jose F.; Saatchi, Susan S.

    1996-01-01

    level, methods are still not fully well established, especially over vegetation-covered areas. In this paper, an algorithm is described which allows derivation of three fundamental parameters from SAR data: soil moisture, soil roughness and canopy water content, accounting for the effects of vegetation cover by using optical (Landsat) data as auxiliary. Capabilities and limitations of the data and algorithms are discussed, as well as possibilities to use these data in energy/water balance modeling studies. All the data used in this study were acquired as part of the Intensive Observation Period in June-July 1991 (European Multisensor Aircraft Campaign-91), as part of the European Field Experiment in a Desertification- threatened Area (EFEDA), a European contribution to the global-change research sponsored by the IGBP program (Bolle et al., 1993).

  10. A discussion of Bl conservation on a two dimensional magnetic field plane in watt balances

    NASA Astrophysics Data System (ADS)

    Li, Shisong; Zhao, Wei; Huang, Songling

    2016-05-01

    The watt balance is an experiment being pursued in national metrology institutes for precision determination of the Planck constant h. In watt balances, the 1/r magnetic field, expected to generate a geometrical factor Bl independent to any coil horizontal displacement, can be created by a strict two dimensional, symmetric (horizontal r and vertical z) construction of the magnet system. In this paper, we present an analytical understanding of magnetic field distribution when the r symmetry of the magnet is broken and the establishment of the Bl conservation is shown. By using either Gauss’s law on magnetism with monopoles or conformal transformations, we extend the Bl conservation to arbitrary two dimensional magnetic planes where the vertical magnetic field component equals zero. The generalized Bl conservation allows a relaxed physical alignment criteria for watt balance magnet systems.

  11. Water balance of selected floodplain lake basins in the Middle Bug River valley

    NASA Astrophysics Data System (ADS)

    Dawidek, J.; Ferencz, B.

    2014-04-01

    This study is the first attempt in the literature on the subject of comparing water balance components for floodplain lake basins, depending on the type of a lake connection to the parent river. Research was carried out in the Bug River valley in 2007-2011 water years. Four types of connections were distinguished in the area under study. Simple water balance equation could only be used with regard to the lakes connected to the main river via the upstream crevasses. Detailed and individual water balance equations were developed with reference to the other types of lakes. Water gains and losses varied significantly in the lakes under study. Values of horizontal water balance components (inflow and outflow) of the floodplain lake in Wola Uhruska considerably prevailed over the vertical ones (precipitation and evaporation). Inflow of the Bug River waters was diverse during the time period under study and amounted from 600 000 to 2 200 000 m3 yr-1. Volumes of precipitation and evaporation were rather stable and amounted to approx. 30 000 m3 yr-1. The lowest disparity between horizontal and vertical water balance components was observed in the inter-levee lake. Both upstream inflow of rivers water and outflow from the lake (ranged from 0 in 2008 to 35 000 m3 yr-1 in 2009) were usually an order of magnitude higher than precipitation and evaporation from the lake surface (700-800 m3 yr-1). Study showed that the values and the proportion between aforementioned vertical and horizontal water balance elements were determined by the type of a lake connection to the Bug River. Storage volume showed no relationship to the type of connection, but resulted from individual features of the lakes (location within the valley, precipitation and evaporation volume, difference between water inflow and outflow).

  12. Changes in serum sodium, sodium balance, water balance, and plasma hormone levels as the result of pelvic surgery in women.

    PubMed

    Amede, Francis J; James, Kenneth A; Michelis, Michael F; Gleim, Gilbert W

    Postoperative hyponatremia in women has been associated with the development of serious neurological disorders and even death, with a predisposition for menstruant women. The objective of this study was to evaluate the immediate hormonal, water and electrolyte responses to pelvic surgery in both pre and postmenopausal women. Of the twenty-five consecutive women studied, twenty were premenopausal while five were postmenopausal. Mean age was 45.4 +/- 1.6 years. Measurements of plasma renin activity, follicular stimulating hormone and luteinizing hormone showed no significant change pre to postoperatively. There was a significant decrease in pre to postoperative values of estrogen, 97.4 +/- 20.3 to 36.3 +/- 7.5 pg/mL (p < 0.05). There was also a significant decline in postoperative values for plasma aldosterone and plasma progesterone. Data were similar in pre and postmenopausal patients. Serum sodium levels decreased from 141.5 +/- 0.5 to 137.2 +/- 0.5 mEq/L (p < 0.01). During the twenty-four hours following surgery, mean net sodium balance was positive 122 mEq and mean measured fluid balance was positive 1108 mL. Ringers lactate or normal saline were used. On the first postoperative day, plasma arginine vasopressin levels were elevated at 4.0 +/- 0.8 pg/mL, with a mean urine osmolality of 504 +/- 29 mOsm/kg H2O. The data illustrate that women undergoing pelvic surgery decrease their serum sodium in the immediate postoperative period. Despite both positive sodium and water balance, there is a stronger tendency to conserve water. Decreased estrogen levels occur and this decrease may facilitate brain cell adaptation to plasma hypotonicity. Since the administration of isotonic fluid will not protect against the decrease in serum sodium, postoperative sodium concentration should be carefully monitored. PMID:14577502

  13. Automated soil water balance sensing: From layers to control volumes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuous sensing of soil water status has been possible in some ways since the advent of chart recorders, but the widespread adoption of soil water sensing systems did not occur until relatively inexpensive dataloggers became available in the late 1970s and early 1980s. Early systems relied on pre...

  14. A water balance model to estimate flow through the Old and Middle River corridor

    USGS Publications Warehouse

    Andrews, Stephen W.; Gross, Edward S.; Hutton, Paul H.

    2016-01-01

    We applied a water balance model to predict tidally averaged (subtidal) flows through the Old River and Middle River corridor in the Sacramento–San Joaquin Delta. We reviewed the dynamics that govern subtidal flows and water levels and adopted a simplified representation. In this water balance approach, we estimated ungaged flows as linear functions of known (or specified) flows. We assumed that subtidal storage within the control volume varies because of fortnightly variation in subtidal water level, Delta inflow, and barometric pressure. The water balance model effectively predicts subtidal flows and approaches the accuracy of a 1–D Delta hydrodynamic model. We explore the potential to improve the approach by representing more complex dynamics and identify possible future improvements.

  15. IAEA Isotope-enabled coupled catchment-lake water balance model, IWBMIso: description and validation.

    PubMed

    Belachew, Dagnachew Legesse; Leavesley, George; David, Olaf; Patterson, Dave; Aggarwal, Pradeep; Araguas, Luis; Terzer, Stefan; Carlson, Jack

    2016-01-01

    The International Atomic Energy Agency (IAEA) Water Balance Model with Isotopes (IWBMIso) is a spatially distributed monthly water balance model that considers water fluxes and storages and their associated isotopic compositions. It is composed of a lake water balance model that is tightly coupled with a catchment water balance model. Measured isotope compositions of precipitation, rivers, lakes, and groundwater provide data that can be used to make an improved estimate of the magnitude of the fluxes among the model components. The model has been developed using the Object Modelling System (OMS). A variety of open source geographic information systems and web-based tools have been combined to provide user support for (1) basin delineation, characterization, and parameterization; (2) data pre-processing; (3) model calibration and application; and (4) visualization and analysis of model results. In regions where measured data are limited, the model can use freely available global data sets of climate, isotopic composition of precipitation, and soils and vegetation characteristics to create input data files and estimate spatially distributed model parameters. The OMS model engine and support functions, and the spatial and web-based tool set are integrated using the Colorado State University Environmental Risk Assessment and Management System (eRAMS) framework. The IWBMIso can be used to assess the spatial and temporal variability of annual and monthly water balance components for input to water planning and management. PMID:26962894

  16. Energy balance closure on a winter wheat stand: comparing the eddy covariance technique with the soil water balance method

    NASA Astrophysics Data System (ADS)

    Imukova, K.; Ingwersen, J.; Hevart, M.; Streck, T.

    2015-05-01

    The energy balance of eddy covariance (EC) flux data is typically not closed. The nature of the gap is usually not known, which hampers using EC data to parameterize and test models. The present study elucidates the nature of the energy gap of EC flux data from winter wheat stands in southwest Germany. During the vegetation periods 2012 and 2013, we continuously measured, in a half-hourly resolution, latent (LE) and sensible (H) heat fluxes using the EC technique. Measured fluxes were adjusted with either the Bowen-ratio (BR), H or LE post-closure method. The adjusted LE fluxes were tested against evapotranspiration data (ETWB) calculated using the soil water balance (WB) method. At sixteen locations within the footprint of an EC station, the soil water storage term was determined by measuring the soil water content down to a soil depth of 1.5 m. In the second year, the volumetric soil water content was also continuously measured in 15 min resolution in 10 cm intervals down to 90 cm depth with sixteen capacitance soil moisture sensors. During the 2012 vegetation period, the H post-closed LE flux data (ETEC = 3.4 ± 0.6 mm day-1) corresponded closest with the result of the WB method (3.3 ± 0.3 mm day-1). ETEC adjusted by the BR (4.1 ± 0.6 mm day-1) or LE (4.9 ± 0.9 mm day-1) post-closure method were higher than the ETWB by 20 and 33%, respectively. In 2013, ETWB was in best agreement with ETEC adjusted with the H post-closure method during the periods with low amount of rain and seepage. During these periods the BR and LE post-closure methods overestimated ET by about 30 and 40%, respectively. During a period with high and frequent rainfalls, ETWB was in-between ETEC adjusted by H and BR post-closure methods. We conclude that, at most vegetation periods on our site, LE is not a~major component of the energy balance gap. Our results indicate that the energy balance gap other energy fluxes and unconsidered or biased energy storage terms.

  17. Preservation of potassium balance is strongly associated with insect cold tolerance in the field: a seasonal study of Drosophila subobscura.

    PubMed

    MacMillan, Heath A; Schou, Mads F; Kristensen, Torsten N; Overgaard, Johannes

    2016-05-01

    There is interest in pinpointing genes and physiological mechanisms explaining intra- and interspecific variations in cold tolerance, because thermal tolerance phenotypes strongly impact the distribution and abundance of wild animals. Laboratory studies have highlighted that the capacity to preserve water and ion homeostasis is linked to low temperature survival in insects. It remains unknown, however, whether adaptive seasonal acclimatization in free-ranging insects is governed by the same physiological mechanisms. Here, we test whether cold tolerance in field-caught Drosophila subobscura is high in early spring and lower during summer and whether this transition is associated with seasonal changes in the capacity of flies to preserve water and ion balance during cold stress. Indeed, flies caught during summer were less cold tolerant, and exposure of these flies to sub-zero temperatures caused a loss of haemolymph water and increased the concentration of K(+) in the haemolymph (as in laboratory-reared insects). This pattern of ion and water balance disruption was not observed in more cold-tolerant flies caught in early spring. Thus, we here provide a field verification of hypotheses based on laboratory studies and conclude that the ability to maintain ion homeostasis is important for the ability of free-ranging insects to cope with chilling. PMID:27165627

  18. Eddy Covariance Measurements Over a Maize Field: The Contribution of Minor Flux Terms to the Energy Balance Gap

    NASA Astrophysics Data System (ADS)

    Smidt, J.; Ingwersen, J.; Streck, T.

    2015-12-01

    The lack of energy balance closure is a long-standing problem in eddy covariance (EC) measurements. The energy balance equation is defined as Rn - G = H + λE, where Rn is net radiation, G is the ground heat flux, H is the sensible heat flux and λE is the latent heat flux. In most cases of energy imbalance, either Rn is overestimated or the ground heat and turbulent fluxes are underestimated. Multiple studies have shown that calculations, incorrect instrument installation/calibration and measurement errors alone do not entirely account for this imbalance. Rather, research is now focused on previously neglected sources of heat storage in the soil, biomass and air beneath the EC station. This project examined the potential of five "minor flux terms" - soil heat storage, biomass heat storage, energy consumption by photosynthesis, air heat storage and atmospheric moisture change, to further close the energy balance gap. Eddy covariance measurements were conducted at a maize (Zea mays) field in southwest Germany during summer 2014. Soil heat storage was measured for six weeks at 11 sites around the field footprint. Biomass and air heat storage were measured for six subsequent weeks at seven sites around the field footprint. Energy consumption by photosynthesis was calculated using the CO2 flux data. Evapotranspiration was calculated using the water balance method and then compared to the flux data processed with three post-closure methods: the sensible heat flux, the latent heat flux and the Bowen ratio post-closure methods. An energy balance closure of 66% was achieved by the EC station measurements over the entire investigation period. During the soil heat flux campaign, EC station closure was 74.1%, and the field footprint soil heat storage contributed 3.3% additional closure. During the second minor flux term measurement period, closure with the EC station data was 91%. Biomass heat storage resulted in 1.1% additional closure, the photosynthesis flux closed the gap

  19. Determining water and nitrogen balances for beneficial management practices using lysimeters at Wagna test site (Austria).

    PubMed

    Klammler, Gernot; Fank, Johann

    2014-11-15

    The shallow Murtal aquifer south of Graz, Austria, provides easily withdrawable groundwater, which is supplied as drinking water without any chemical treatment. The aquifer is also used intensively by agriculture. Common agricultural management practices are the main source for diffuse nitrogen leaching and high groundwater nitrate concentrations. To safeguard the coexisting use of these two important resources, lysimeters are operated at the agricultural test site Wagna, Austria, and the influence of two beneficial management practices--low nitrogen input and organic farming--on nitrogen leaching towards groundwater is investigated. The technical lysimeter design as presented here consists of: (1) high-resolution weighing cells, (2) a suction controlled lower boundary condition for sucking off seepage water, thus emulating undisturbed field conditions, (3) comparative soil temperature, water content and matrix potential measurements inside and outside the lysimeter at different depths, (4) an installation of the lysimeters directly into test plots and (5) a removable upper lysimeter ring enabling machinery soil tillage. Our results indicate that oasis effects or fringe effects of the lysimeter cylinder on unsaturated water flow did not occur. Another lysimeter cultivated with lawn is operated for observing grass-reference evapotranspiration, which resulted in good agreement with calculated grass-reference evapotranspiration according to the FAO-Penman-Monteith method. We conclude that lysimeters installed at Wagna test site did not show any fringe effects and, thus, are appropriate tools for measuring water balance elements and nitrogen leaching of arable and grass land at point scale. Furthermore, our results for the period of 2005 to 2011 show that beneficial management practices reduced nitrate leaching and, hence, may allow for a sustainable coexistence of drinking water supply and agriculture in the Murtal aquifer. PMID:24982000

  20. Field investigation to assess nutrient emission from paddy field to surface water in river catchment

    NASA Astrophysics Data System (ADS)

    Kogure, Kanami; Aichi, Masaatsu; Zessner, Matthias

    2015-04-01

    TD water can be sampled for infiltrating water measurement. We installed monitoring wells to measure ground water level and water quality. Inflow, outflow, flooding water, infiltrating water, and ground water were measured and sampled. Regarding to parameters, temperature, pH, EC, DO and COD, main ions were measured to understand characteristic of water quality and transformation processes. Inorganic forms of nitrogen and phosphorus were also measured, as behavior and balance of nitrogen and phosphorus are focused on. We observed following points by taking data of water quality; seasonal trend, changes occurred according to agricultural events like irrigation and fertilization. Nitrogen in ground water tends to high in June due to fertilizer. It is thought because farmers fertilize the filed before transplanting at the beginning of flooding season. Regarding to dissolved inorganic nitrogen, higher concentrations were observed in inflow water than in flooding water and outflow water. Though it needs discussion in loads as well as flow measurement, this suggests that nutrients are absorbed in paddy field and less nutrients are emitted after irrigation water passing through paddy field. Based on this research we are planning continuous investigation to assess environmental impact from paddy field.

  1. Evaporation estimates from the Dead Sea and their implications on its water balance

    NASA Astrophysics Data System (ADS)

    Oroud, Ibrahim M.

    2011-12-01

    The Dead Sea (DS) is a terminal hypersaline water body situated in the deepest part of the Jordan Valley. There is a growing interest in linking the DS to the open seas due to severe water shortages in the area and the serious geological and environmental hazards to its vicinity caused by the rapid level drop of the DS. A key issue in linking the DS with the open seas would be an accurate determination of evaporation rates. There exist large uncertainties of evaporation estimates from the DS due to the complex feedback mechanisms between meteorological forcings and thermophysical properties of hypersaline solutions. Numerous methods have been used to estimate current and historical (pre-1960) evaporation rates, with estimates differing by ˜100%. Evaporation from the DS is usually deduced indirectly using energy, water balance, or pan methods with uncertainty in many parameters. Accumulated errors resulting from these uncertainties are usually pooled into the estimates of evaporation rates. In this paper, a physically based method with minimum empirical parameters is used to evaluate historical and current evaporation estimates from the DS. The more likely figures for historical and current evaporation rates from the DS were 1,500-1,600 and 1,200-1,250 mm per annum, respectively. Results obtained are congruent with field observations and with more elaborate procedures.

  2. Estimating Evapotranspiration in Three Contrasting Forest Ecosystems Using Eddy Covariance, Sapflow, and Soil Water Balance Methods

    NASA Astrophysics Data System (ADS)

    Sun, G.; Cao, W.; Gavazzi, M.; Noormets, A.; Chen, J.; Deforest, J.; Chescheir, C.; Amatya, D. M.; McNulty, S.

    2005-12-01

    Evapotranspiration (ET) represents the second largest flux in terrestrial ecosystem water budget. In recent years, much attention has been given to the coherent linkages among hydrological cycle, ecophysiological processes, disturbances, and ecosystem function. However, quantification of ET at various temporal and spatial scales remains challenging (e.g., continuous changes of ET with time of a forest). Large uncertainties and measurement errors exist in fully accounting the ET flux, a process that involves both the physical (atmospheric and soil water control) and biological processes (leaf stomata and stem conductance control). In 2004, we established three research sites to study the climatic and forest management effects on ecosystem carbon and water balances in three contrasting forests: an oak openings in NW Ohio, a recent plantation of loblolly pine in eastern North Carolina, and a 13 year-old loblolly pine stand in eastern NC. The oak-opening ecosystem in a dry, cold environment while the other two in eastern North Carolina's lower coastal plain represent loblolly pine plantations on drained soils. Field installation on each site includes an eddy flux tower to measure ecosystem water exchange at 30-minute interval. Forest canopy interception, soil water content, and groundwater table depth were monitored around the flux tower along with rainfall above the forest canopy to develop water balances at multiple temporal scales. Stand-level transpiration was estimated by scaling up sapflow flux of 6-16 trees. Estimated ET values from the three independent methods were compared to identify major controls of ET. We also applied the MIKE SHE hydrologic model with site specific stand and soil information to simulate ET and compare with the measured data at the daily temporal scale. From the one-year data, we found that: 1) Ecosystem ET had very high natural variability, thus any single method was insufficient to quantify and model it at a high temporal resolution; 2

  3. Maintaining Atmospheric Mass and Water Balance Within Reanalysis

    NASA Technical Reports Server (NTRS)

    Takacs, Lawrence L.; Suarez, Max; Todling, Ricardo

    2015-01-01

    This report describes the modifications implemented into the Goddard Earth Observing System Version-5 (GEOS-5) Atmospheric Data Assimilation System (ADAS) to maintain global conservation of dry atmospheric mass as well as to preserve the model balance of globally integrated precipitation and surface evaporation during reanalysis. Section 1 begins with a review of these global quantities from four current reanalysis efforts. Section 2 introduces the modifications necessary to preserve these constraints within the atmospheric general circulation model (AGCM), the Gridpoint Statistical Interpolation (GSI) analysis procedure, and the Incremental Analysis Update (IAU) algorithm. Section 3 presents experiments quantifying the impact of the new procedure. Section 4 shows preliminary results from its use within the GMAO MERRA-2 Reanalysis project. Section 5 concludes with a summary.

  4. Finding Balance Between Biological Groundwater Treatment and Treated Injection Water

    SciTech Connect

    Carlson, Mark A.; Nielsen, Kellin R.; Byrnes, Mark E.; Simmons, Sally A.; Morse, John J.; Geiger, James B.; Watkins, Louis E.; McFee, Phillip M.; Martins, K.

    2015-01-14

    At the U.S. Department of Energy’s Hanford Site, CH2M HILL Plateau Remediation Company operates the 200 West Pump and Treat which was engineered to treat radiological and chemical contaminants in groundwater as a result of the site’s former plutonium production years. Fluidized bed bioreactors (FBRs) are used to remove nitrate, metals, and volatile organic compounds. Increasing nitrate concentrations in the treatment plant effluent and the presence of a slimy biomass (a typical microorganism response to stress) in the FBRs triggered an investigation of nutrient levels in the system. Little, if any, micronutrient feed was coming into the bioreactors. Additionally, carbon substrate (used to promote biological growth) was passing through to the injection wells, causing biological fouling of the wells and reduced specific injectivity. Adjustments to the micronutrient feed improved microorganism health, but the micronutrients were being overfed (particularly manganese) plugging the injection wells further. Injection well rehabilitation to restore specific injectivity required repeated treatments to remove the biological fouling and precipitated metal oxides. A combination of sulfamic and citric acids worked well to dissolve metal oxides and sodium hypochlorite effectively removed the biological growth. Intensive surging and development techniques successfully removed clogging material from the injection wells. Ultimately, the investigation and nutrient adjustments took months to restore proper balance to the microbial system and over a year to stabilize injection well capacities. Carefully tracking and managing the FBRs and well performance monitoring are critical to balancing the needs of the treatment system while reducing fouling mechanisms in the injection wells.

  5. Sustainable Hydro Assessment and Groundwater Recharge Projects (SHARP) in Germany - Water Balance Models

    NASA Astrophysics Data System (ADS)

    Niemand, C.; Kuhn, K.; Schwarze, R.

    2010-12-01

    SHARP is a European INTERREG IVc Program. It focuses on the exchange of innovative technologies to protect groundwater resources for future generations by considering the climate change and the different geological and geographical conditions. Regions involved are Austria, United Kingdom, Poland, Italy, Macedonia, Malta, Greece and Germany. They will exchange practical know-how and also determine know-how demands concerning SHARP’s key contents: general groundwater management tools, artificial groundwater recharge technologies, groundwater monitoring systems, strategic use of groundwater resources for drinking water, irrigation and industry, techniques to save water quality and quantity, drinking water safety plans, risk management tools and water balance models. SHARP Outputs & results will influence the regional policy in the frame of sustainable groundwater management to save and improve the quality and quantity of groundwater reservoirs for future generations. The main focus of the Saxon State Office for Environment, Agriculture and Landscape in this project is the enhancement and purposive use of water balance models. Already since 1992 scientists compare different existing water balance models on different scales and coupled with groundwater models. For example in the KLIWEP (Assessment of Impacts of Climate Change Projections on Water and Matter Balance for the Catchment of River Parthe in Saxony) project the coupled model WaSiM-ETH - PCGEOFIM® has been used to study the impact of climate change on water balance and water supplies. The project KliWES (Assessment of the Impacts of Climate Change Projections on Water and Matter Balance for Catchment Areas in Saxony) still running, comprises studies of fundamental effects of climate change on catchments in Saxony. Project objective is to assess Saxon catchments according to the vulnerability of their water resources towards climate change projections in order to derive region-specific recommendations for

  6. A Simple Water Balance Approach to Monitor Lake Water Level Changes: Validation using TOPEX/Poseidon and Jason Altimetry Data

    NASA Astrophysics Data System (ADS)

    Velpuri, N.; Senay, G. B.; Alemu, H.; Asante, K. O.

    2008-12-01

    A simple water balance approach is adapted to monitor water resources in semi-arid region of east Africa by integrating coarse and dynamic datasets such as rainfall with fine and static elevation datasets. The model takes in Tropical Rainfall Measuring Mission (TRMM) rainfall data, modeled runoff and reference evapotranspiration (ET) data to monitor changes in lake water heights. Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) was used to delineate lake Turkana watershed. A simple water balance modeling approach was applied on Turkana basin to estimate lake water level heights for ten years (1997- 2008) and the results were compared with TOPEX/Poseidon and Jason satellite altimeter data. It was observed that simple water balance approach could capture the trend and seasonal variations of lake water fluctuations as measured by the satellite. The El Nino year of 1998 and the following consecutive dry years until 2002 are captured well on both. A mean deviation up to 30 cm of lake water height was found when compared to the satellite measurements. The satellite measurements made since 2004 showed that the lake water height gradually reduced, whereas simulations made using the water balance model showed an increasing trend. This could be reasoned by the fact that, on the Omo river, which contributes to over 80% of the lake inflows, a dam was commissioned in 2004. Knowledge of such processes occurring upstream or downstream is often required while analyzing satellite altimetry data to avoid misinterpretation. Although the absolute accuracy is low, the advantage of the simple water balance method lies in its ability to: (i) capture the trend and seasonal variations of water level fluctuations of small to large lakes around the world; (ii) when coupled with ground measurements or satellite altimetry data for lake water heights, the simple water balance method can identify the presence and absence of upstream and downstream processes; (iii) since water

  7. Evaluation of military field-water quality

    SciTech Connect

    Daniels, J.I.; Anspaugh, L.R.; Layton, D.W.

    1990-01-01

    The purpose of this report is to develop drinking-water standards for field water for selected threat agents of concern, including radioactivity. The threat agents of concern in addition to radioactivity are the classical chemical-warfare compounds hydrogen cyanide, organophosphorus nerve agents, and lewisite, as well as a fungal metabolite identified only recently as a possible threat agent, the trichothecene mycotoxin. The recommended standards are applicable only to military personnel deployed in the field, and they are meant to protect against performance-degrading effects resulting from the ingestion of the substances in field water. 25 refs., 11 figs., 19 tabs.

  8. Surface fluxes and water balance of spatially varying vegetation within a small mountainous headwater catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding the role of ecosystems in modulating energy, water and carbon fluxes is critical to quantifying the variability in energy, carbon, and water balances across landscapes. This study compares and contrasts the seasonal surface fluxes of sensible heat, latent heat and carbon fluxes measur...

  9. [Stress-resistance and the condition of surfactant system and water balance in the lung of suspended rats].

    PubMed

    Bryndina, I G; Vasilieva, N N; Baranov, V M

    2013-01-01

    White male rats with the body mass of 180-220 grams were distributed into the open-field active (presumably stress-resistant) and open-field inactive (presumably stress vulnerable) groups for a 10-day experimental suspension with the purpose to evaluate the surfactant activity in bronchoalveolar lavages, total phospholipids and their fractions, and water balance in the lung. In modeled microgravity, augmented blood filling of the rat's lung increases the alveolar phospholipid content and alters the phospholipid fractional composition in the pulmonary surfactant. Ten-day suspension raises pulmonary surfactant activity to a greater extent in stress-resistant animals rather than in their stress vulnerable peers. PMID:24032163

  10. Balancing water scarcity and quality for sustainable irrigated agriculture

    NASA Astrophysics Data System (ADS)

    Assouline, Shmuel; Russo, David; Silber, Avner; Or, Dani

    2015-05-01

    The challenge of meeting the projected doubling of global demand for food by 2050 is monumental. It is further exacerbated by the limited prospects for land expansion and rapidly dwindling water resources. A promising strategy for increasing crop yields per unit land requires the expansion of irrigated agriculture and the harnessing of water sources previously considered "marginal" (saline, treated effluent, and desalinated water). Such an expansion, however, must carefully consider potential long-term risks on soil hydroecological functioning. The study provides critical analyses of use of marginal water and management approaches to map out potential risks. Long-term application of treated effluent (TE) for irrigation has shown adverse impacts on soil transport properties, and introduces certain health risks due to the persistent exposure of soil biota to anthropogenic compounds (e.g., promoting antibiotic resistance). The availability of desalinated water (DS) for irrigation expands management options and improves yields while reducing irrigation amounts and salt loading into the soil. Quantitative models are used to delineate trends associated with long-term use of TE and DS considering agricultural, hydrological, and environmental aspects. The primary challenges to the sustainability of agroecosystems lies with the hazards of saline and sodic conditions, and the unintended consequences on soil hydroecological functioning. Multidisciplinary approaches that combine new scientific knowhow with legislative, economic, and societal tools are required to ensure safe and sustainable use of water resources of different qualities. The new scientific knowhow should provide quantitative models for integrating key biophysical processes with ecological interactions at appropriate spatial and temporal scales.

  11. Recharge Estimation Using Water, Chloride and Isotope Mass Balances

    NASA Astrophysics Data System (ADS)

    Dogramaci, S.; Firmani, G.; Hedley, P.; Skrzypek, G.; Grierson, P. F.

    2014-12-01

    Discharge of surplus mine water into ephemeral streams may elevate groundwater levels and alter the exchange rate between streams and underlying aquifers but it is unclear whether volumes and recharge processes are within the range of natural variability. Here, we present a case study of an ephemeral creek in the semi-arid subtropical Hamersley Basin that has received continuous mine discharge for more than five years. We used a numerical model coupled with repeated measurements of water levels, chloride concentrations and the hydrogen and oxygen stable isotope composition (δ2H and δ18O) to estimate longitudinal evapotranspiration and recharge rates along a 27 km length of Weeli Wolli Creek. We found that chloride increased from 74 to 120 mg/L across this length, while δ18O increased from -8.24‰ to -7.00‰. Groundwater is directly connected to the creek for the first 13 km and recharge rates are negligible. Below this point, the creek flows over a highly permeable aquifer and water loss by recharge increases to a maximum rate of 4.4 mm/d, which accounts for ~ 65% of the total water discharged to the creek. Evapotranspiration losses account for the remaining ~35%. The calculated recharge from continuous flow due to surplus water discharge is similar to that measured for rainfall-driven flood events along the creek. Groundwater under the disconnected section of the creek is characterised by a much lower Cl concentration and more depleted δ18O value than mining discharge water but is similar to flood water generated by large episodic rainfall events. Our results suggest that the impact of recharge from continuous flow on the creek has not extended beyond 27 km from the discharge point. Our approach using a combination of hydrochemical and isotope methods coupled with classical surface flow hydraulic modelling allowed evaluation of components of water budget otherwise not possible in a highly dynamic system that is mainly driven by infrequent but large episodic

  12. Physical Limitations of Empirical Field Models: Force Balance and Plasma Pressure

    SciTech Connect

    Sorin Zaharia; C.Z. Cheng

    2002-06-18

    In this paper, we study whether the magnetic field of the T96 empirical model can be in force balance with an isotropic plasma pressure distribution. Using the field of T96, we obtain values for the pressure P by solving a Poisson-type equation {del}{sup 2}P = {del} {center_dot} (J x B) in the equatorial plane, and 1-D profiles on the Sun-Earth axis by integrating {del}P = J x B. We work in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials. Our results lead to the conclusion that the T96 model field cannot be in equilibrium with an isotropic pressure. We also analyze in detail the computation of Birkeland currents using the Vasyliunas relation and the T96 field, which yields unphysical results, again indicating the lack of force balance in the empirical model. The underlying reason for the force imbalance is likely the fact that the derivatives of the least-square fitted model B are not accurate predictions of the actual magnetospheric field derivatives. Finally, we discuss a possible solution to the problem of lack of force balance in empirical field models.

  13. Water balance of a lake with floodplain buffering: Lake Tana, Blue Nile Basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Dessie, Mekete; Verhoest, Niko E. C.; Pauwels, Valentijn R. N.; Adgo, Enyew; Deckers, Jozef; Poesen, Jean; Nyssen, Jan

    2015-03-01

    Lakes are very important components of the earth's hydrological cycle, providing a variety of services for humans and ecosystem functioning. For a sustainable use of lakes, a substantial body of knowledge on their water balance is vital. We present here a detailed daily water balance analysis for Lake Tana, the largest lake in Ethiopia and the source of the Blue Nile. Rainfall on the lake is determined by Thiessen polygon procedure, open water evaporation is estimated by the Penman-combination equation and observed inflows for the gauged catchments as well as outflow data at the two lake outlets are directly used. Runoff from ungauged catchments is estimated using a simple rainfall-runoff model and runoff coefficients. Hillslope catchments and floodplains are treated separately, which makes this study unique compared to previous water balance studies. Impact of the floodplain on the lake water balance is analyzed by conducting scenario-based studies. We found an average yearly abstraction of 420 × 106 m3 or 6% of river inflows to the lake by the floodplain in 2012 and 2013. Nearly 60% of the inflow to the lake is from the Gilgel Abay River. Simulated lake levels compare well with the observed lake levels (R2 = 0.95) and the water balance can be closed with a closure error of 82 mm/year (3.5% of the total lake inflow). This study demonstrates the importance of floodplains and their influence on the water balance of the lake and the need of incorporating the effects of floodplains and water abstraction for irrigation to improve predictions.

  14. Effect of exposure on the water balance of two identical lysimeters

    NASA Astrophysics Data System (ADS)

    Hagenau, J.; Meissner, R.; Borg, H.

    2015-01-01

    This study looks at the water balance of two identical weighable lysimeters located right next to each other. They contain the same soil and are managed in the same way. Both were planted with maize. The area around them was planted with maize, too, to ensure that the lysimeters were located inside a crop. The only difference between them was that one side of lysimeter 2 was exposed due to a footpath. At first both yielded similar results. However, as the maize became taller lysimeter 2 began to show consistently more precipitation and drainage. After harvest the differences disappeared again. Since precipitation often falls at an angle, a crop with an exposed side receives more than a crop without one, if the precipitation falls towards the exposed side. The additional precipitation a crop with an exposed side may capture increases with the height of the crop. After harvest this exposure effect therefore disappears completely. Compared to lysimeter 1, lysimeter 2 accumulated >100 mm of additional precipitation during the growth of the maize. After the maize was removed, both crops recorded the same amount of precipitation again. Lysimeter 2 showed more drainage, too, because the additional precipitation led to higher water contents, which in turn caused the water holding capacity of the soil to be exceeded on more days than in the case of lysimeter 1. The difference in actual evapotranspiration was small, because lysimeter 2 was exposed towards west-northwest and therefore received only little more radiation, and because the distribution of the rainfall pattern was such that the additional precipitation led to a similar amount of additional drainage rather than to an increase in the volume of stored water, which could have been consumed by evapotranspiration later. The data clearly illustrate that exposure can significantly alter the water balance of a lysimeter, which makes it inadvisable to extrapolate data obtained under such circumstances to the field. This

  15. 40 CFR 1065.295 - PM inertial balance for field-testing analysis.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false PM inertial balance for field-testing analysis. 1065.295 Section 1065.295 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Pm Measurements § 1065.295...

  16. 40 CFR 1065.295 - PM inertial balance for field-testing analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false PM inertial balance for field-testing analysis. 1065.295 Section 1065.295 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Pm Measurements § 1065.295...

  17. 40 CFR 1065.295 - PM inertial balance for field-testing analysis.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false PM inertial balance for field-testing analysis. 1065.295 Section 1065.295 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Pm Measurements § 1065.295...

  18. 40 CFR 1065.295 - PM inertial balance for field-testing analysis.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false PM inertial balance for field-testing analysis. 1065.295 Section 1065.295 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Pm Measurements § 1065.295...

  19. 40 CFR 1065.295 - PM inertial balance for field-testing analysis.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false PM inertial balance for field-testing analysis. 1065.295 Section 1065.295 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Measurement Instruments Pm Measurements § 1065.295...

  20. Insight into glacier climate interaction: reconstruction of the mass balance field using ice extent data

    NASA Astrophysics Data System (ADS)

    Visnjevic, Vjeran; Herman, Frédéric; Licul, Aleksandar

    2016-04-01

    With the end of the Last Glacial Maximum (LGM), about 20 000 years ago, ended the most recent long-lasting cold phase in Earth's history. We recently developed a model that describes large-scale erosion and its response to climate and dynamical changes with the application to the Alps for the LGM period. Here we will present an inverse approach we have recently developed to infer the LGM mass balance from known ice extent data, focusing on a glacier or ice cap. The ice flow model is developed using the shallow ice approximation and the developed codes are accelerated using GPUs capabilities. The mass balance field is the constrained variable defined by the balance rate β and the equilibrium line altitude (ELA), where c is the cutoff value: b = max(βṡ(S(z) - ELA), c) We show that such a mass balance can be constrained from the observed past ice extent and ice thickness. We are also investigating several different geostatistical methods to constrain spatially variable mass balance, and derive uncertainties on each of the mass balance parameters.

  1. Atmospheric water balance over oceanic regions as estimated from satellite, merged, and reanalysis data

    NASA Astrophysics Data System (ADS)

    Park, Hyo-Jin; Shin, Dong-Bin; Yoo, Jung-Moon

    2013-05-01

    The column integrated atmospheric water balance over the ocean was examined using satellite-based and merged data sets for the period from 2000 to 2005. The data sets for the components of the atmospheric water balance include evaporation from the HOAPS, GSSTF, and OAFlux and precipitation from the HOAPS, CMAP, and GPCP. The water vapor tendency was derived from water vapor data of HOAPS. The product for water vapor flux convergence estimated using satellite observation data was used. The atmospheric balance components from the MERRA reanalysis data were also examined. Residuals of the atmospheric water balance equation were estimated using nine possible combinations of the data sets over the ocean between 60°N and 60°S. The results showed that there was considerable disagreement in the residual intensities and distributions from the different combinations of the data sets. In particular, the residuals in the estimations of the satellite-based atmospheric budget appear to be large over the oceanic areas with heavy precipitation such as the intertropical convergence zone, South Pacific convergence zone, and monsoon regions. The lack of closure of the atmospheric water cycle may be attributed to the uncertainties in the data sets and approximations in the atmospheric water balance equation. Meanwhile, the anomalies of the residuals from the nine combinations of the data sets are in good agreement with their variability patterns. These results suggest that significant consideration is needed when applying the data sets of water budget components to quantitative water budget studies, while climate variability analysis based on the residuals may produce similar results.

  2. Balancing Ground-Water Withdrawals and Streamflow in the Hunt-Annaquatucket-Pettaquamscutt Basin, Rhode Island

    USGS Publications Warehouse

    Barlow, Paul M.; Dickerman, David C.

    2001-01-01

    Ground water withdrawn for water supply reduces streamflow in the Hunt-Annaquatucket-Pettaquamscutt Basin in Rhode Island. These reductions may adversely affect aquatic habitats. A hydrologic model was prepared by the U.S. Geological Survey in cooperation with the Rhode Island Water Resources Board, Town of North Kingstown, Rhode Island Department of Environmental Management, and Rhode Island Economic Development Corporation to aid water-resource planning in the basin. Results of the model provide information that helps water suppliers and natural-resource managers evaluate strategies for balancing ground-water development and streamflow reductions in the basin.

  3. Water and solute balances as a basis for sustainable irrigation agriculture

    NASA Astrophysics Data System (ADS)

    Pla-Sentís, Ildefonso

    2015-04-01

    The growing development of irrigated agriculture is necessary for the sustainable production of the food required by the increasing World's population. Such development is limited by the increasing scarcity and low quality of the available water resources and by the competitive use of the water for other purposes. There are also increasing problems of contamination of surface and ground waters to be used for other purposes by the drainage effluents of irrigated lands. Irrigation and drainage may cause drastic changes in the regime and balance of water and solutes (salts, sodium, contaminants) in the soil profile, resulting in problems of water supply to crops and problems of salinization, sodification and contamination of soils and ground waters. This is affected by climate, crops, soils, ground water depth, irrigation and groundwater composition, and by irrigation and drainage management. In order to predict and prevent such problems for a sustainable irrigated agriculture and increased efficiency in water use, under each particular set of conditions, there have to be considered both the hydrological, physical and chemical processes determining such water and solute balances in the soil profile. In this contribution there are proposed the new versions of two modeling approaches (SOMORE and SALSODIMAR) to predict those balances and to guide irrigation water use and management, integrating the different factors involved in such processes. Examples of their application under Mediterranean and tropical climate conditions are also presented.

  4. Coherent Structure Patterns Affect Energy Balance Closure: Evidence from Virtual Measurements for a Field Campaign

    NASA Astrophysics Data System (ADS)

    Zhang, S.; De Roo, F.; Heinze, R.; Eder, F.; Huq, S.; Schmidt, M.; Kalthoff, N.; Mauder, M.

    2015-12-01

    The energy balance closure problem is a well-known issue of eddy-covariance measurements. However, the underlying mechanisms are still under debate. Recent evidence suggests that organized low-frequency motion contributes significantly to the energy balance residual, because the associated transport cannot be captured by a point measurement. In this study, we carry out virtual measurements using a PArallelized Large-Eddy Simulation Model (PALM). In order to represent specific measurement days of the field campaign "High definition clouds and precipitation for advancing climate prediction" (HD(CP)²), which was part of the project "High Definition Clouds and Precipitation for Advancing Climate Prediction"(HOPE) in 2013, the simulations were driven by synoptic-scale COSMO-DE reanalysis data. Planet boundary layer height, the vertical profiles of variance and skewness of vertical wind were analyzed and a comparison with Doppler-lidar observations shows good agreement. Furthermore, simulated energy imbalances were compared with real-world imbalances from two eddy-covariance stations in the model domain. Particularly poor energy balance closure was found for a day with cellular organized structures in the surface layer, while the energy balance closure was better on other days with roll-like structures. This finding might be one explanation why the energy balance closure generally tends to improve with increasing friction velocity, since roll-like structures are typically associated with higher wind speeds. In order to gain insight into the partitioning of the energy balance residual between the sensible and latent heat fluxes, we further employed a control volume method within the numerical simulation. Hence, advection and storage terms were identified as the most important causes for the lack of energy balance closure by the eddy-covariance method. The results of the virtual measurements indicate that the "missing" part of the surface energy mainly comes from the

  5. Field evaluation of polymer capacitive humidity sensors for Bowen ratio energy balance flux measurements.

    PubMed

    Savage, Michael J

    2010-01-01

    The possibility of reliable, reasonably accurate and relatively inexpensive estimates of sensible heat and latent energy fluxes was investigated using a commercial combination thin-film polymer capacitive relative humidity and adjacent temperature sensor instrument. Long-term and unattended water vapour pressure profile difference measurements using low-power combination instruments were compared with those from a cooled dewpoint mirror hygrometer, the latter often used with Bowen ratio energy balance (BREB) systems. An error analysis, based on instrument relative humidity and temperature errors, was applied for various capacitive humidity instrument models. The main disadvantage of a combination capacitive humidity instrument is that two measurements, relative humidity and temperature, are required for estimation of water vapour pressure as opposed to one for a dewpoint hygrometer. In a laboratory experiment using an automated procedure, water vapour pressure differences generated using a reference dewpoint generator were measured using a commercial model (Dew-10) dewpoint hygrometer and a combination capacitive humidity instrument. The laboratory measurement comparisons showed that, potentially, an inexpensive model combination capacitive humidity instrument (CS500 or HMP50), or for improved results a slightly more expensive model (HMP35C or HMP45C), could substitute for the more expensive dewpoint hygrometer. In a field study, in a mesic grassland, the water vapour pressure measurement noise for the combination capacitive humidity instruments was greater than that for the dewpoint hygrometer. The average water vapour pressure profile difference measured using a HMP45C was highly correlated with that from a dewpoint hygrometer with a slope less than unity. Water vapour pressure measurements using the capacitive humidity instruments were not as accurate, compared to those obtained using a dewpoint hygrometer, but the resolution magnitudes for the profile

  6. Field Evaluation of Polymer Capacitive Humidity Sensors for Bowen Ratio Energy Balance Flux Measurements

    PubMed Central

    Savage, Michael J.

    2010-01-01

    The possibility of reliable, reasonably accurate and relatively inexpensive estimates of sensible heat and latent energy fluxes was investigated using a commercial combination thin-film polymer capacitive relative humidity and adjacent temperature sensor instrument. Long-term and unattended water vapour pressure profile difference measurements using low-power combination instruments were compared with those from a cooled dewpoint mirror hygrometer, the latter often used with Bowen ratio energy balance (BREB) systems. An error analysis, based on instrument relative humidity and temperature errors, was applied for various capacitive humidity instrument models. The main disadvantage of a combination capacitive humidity instrument is that two measurements, relative humidity and temperature, are required for estimation of water vapour pressure as opposed to one for a dewpoint hygrometer. In a laboratory experiment using an automated procedure, water vapour pressure differences generated using a reference dewpoint generator were measured using a commercial model (Dew-10) dewpoint hygrometer and a combination capacitive humidity instrument. The laboratory measurement comparisons showed that, potentially, an inexpensive model combination capacitive humidity instrument (CS500 or HMP50), or for improved results a slightly more expensive model (HMP35C or HMP45C), could substitute for the more expensive dewpoint hygrometer. In a field study, in a mesic grassland, the water vapour pressure measurement noise for the combination capacitive humidity instruments was greater than that for the dewpoint hygrometer. The average water vapour pressure profile difference measured using a HMP45C was highly correlated with that from a dewpoint hygrometer with a slope less than unity. Water vapour pressure measurements using the capacitive humidity instruments were not as accurate, compared to those obtained using a dewpoint hygrometer, but the resolution magnitudes for the profile

  7. Two strategies by epiphytic orchids for maintaining water balance: thick cuticles in leaves and water storage in pseudobulbs.

    PubMed

    Yang, Shi-Jian; Sun, Mei; Yang, Qiu-Yun; Ma, Ren-Yi; Zhang, Jiao-Lin; Zhang, Shi-Bao

    2016-01-01

    Epiphytes are an important component of tropical and subtropical flora, and serve vital ecological functions in forest hydrology and nutrient fluxes. However, they often encounter water deficits because there is no direct contact between their roots and the soil. The strategies employed by epiphytes for maintaining water balance in relatively water-limited habitats are not completely understood. In the present study, we investigated the anatomical traits, water loss rates, and physiology of leaves and pseudobulbs of four Dendrobium species with different pseudobulb morphologies to understand the roles of leaf and pseudobulb in maintaining water balance of epiphytic orchids. Our results showed that two species (D. chrysotoxum and D. officinale), with lower rates of water loss, have thicker leaves and upper cuticles, but lower epidermal thickness and leaf dry mass per area. In contrast, the other two species (D. chrysanthum and D. crystallinum) with thinner cuticles and higher rates of water loss, have less tissue density and greater saturated water contents in their pseudobulbs. Therefore, our results indicate that these latter two species may resist drought by storing water in the pseudobulbs to compensate for their thin cuticles and rapid water loss through the leaves. Under the same laboratory conditions, excised pseudobulbs with attached leaves had lower rates of water loss when compared with samples comprising only excised leaves. This implies that epiphytic orchids utilize two different strategies for sustaining water balance: thick cuticles to conserve water in leaves and water storage in pseudobulbs. Our results also show that Dendrobium species with thin cuticles tend to have pseudobulbs with high water storage capacity that compensates for their faster rates of water loss. These outcomes contribute to our understanding of the adaptive water-use strategies in Dendrobium species, which is beneficial for the conservation and cultivation of epiphytic orchids

  8. Two strategies by epiphytic orchids for maintaining water balance: thick cuticles in leaves and water storage in pseudobulbs

    PubMed Central

    Yang, Shi-Jian; Sun, Mei; Yang, Qiu-Yun; Ma, Ren-Yi; Zhang, Jiao-Lin; Zhang, Shi-Bao

    2016-01-01

    Epiphytes are an important component of tropical and subtropical flora, and serve vital ecological functions in forest hydrology and nutrient fluxes. However, they often encounter water deficits because there is no direct contact between their roots and the soil. The strategies employed by epiphytes for maintaining water balance in relatively water-limited habitats are not completely understood. In the present study, we investigated the anatomical traits, water loss rates, and physiology of leaves and pseudobulbs of four Dendrobium species with different pseudobulb morphologies to understand the roles of leaf and pseudobulb in maintaining water balance of epiphytic orchids. Our results showed that two species (D. chrysotoxum and D. officinale), with lower rates of water loss, have thicker leaves and upper cuticles, but lower epidermal thickness and leaf dry mass per area. In contrast, the other two species (D. chrysanthum and D. crystallinum) with thinner cuticles and higher rates of water loss, have less tissue density and greater saturated water contents in their pseudobulbs. Therefore, our results indicate that these latter two species may resist drought by storing water in the pseudobulbs to compensate for their thin cuticles and rapid water loss through the leaves. Under the same laboratory conditions, excised pseudobulbs with attached leaves had lower rates of water loss when compared with samples comprising only excised leaves. This implies that epiphytic orchids utilize two different strategies for sustaining water balance: thick cuticles to conserve water in leaves and water storage in pseudobulbs. Our results also show that Dendrobium species with thin cuticles tend to have pseudobulbs with high water storage capacity that compensates for their faster rates of water loss. These outcomes contribute to our understanding of the adaptive water-use strategies in Dendrobium species, which is beneficial for the conservation and cultivation of epiphytic orchids

  9. Linking water balance of mountain grasslands along altitudinal transects to climate and land-use change

    NASA Astrophysics Data System (ADS)

    Leitinger, Georg; Obojes, Nikolaus; Tasser, Erich; Tappeiner, Ulrike

    2010-05-01

    Changes of the water balance of mountain grasslands with regard to climate and land-use changes are a popular research field since years. Measuring evapotranspiration (EVT) for different land-use types and plant communities at varying sea level helps us to understand the change of water availability in a future environment. Linked with transplantation experiments, this method is promising to cover most forecasted scenarios. Although the mentioned approach is well established, our study is innovative in so far as the field work as well as data analyses was supported by more than 50 pupils from a secondary school for agriculture and food industry. Hence, a huge number of field measurements could be conducted at the same time distributed over a whole alpine valley. In our study site Stubai Valley (300km²), Tyrol, Austria, 13 sites on 4 different altitudinal transects (valley bottom, hillside, and sub-alpine/alpine) ranging from 900m a.s.l. up to 2400m a.s.l. were selected and equipped with weather stations recording air temperature, air humidity, precipitation, solar radiation, and soil water content in different soil depths at 15-minute interval. Additionally, more than 300 small lysimeters have been installed and data on EVT, infiltration, leaf conductivity, and soil wetness was collected on 7 measuring days. The measurements spanned an entire daylight period from sunrise to sunset. Moreover, soil and vegetation analyses on all selected plots complete the enormous data pool. The lysimeters on each plot contained samples of long-stemmed local vegetation (1 cut / 1 uncut), short-stemmed local vegetation (1 cut / 1 uncut), alpine standard vegetation (1), intensive standard vegetation (1 cut / 1 uncut), and water for potential transpiration (1). Each type was replicated three times resulting in a total number of 24 lysimeters per study plot. Results revealed a little increase in EVT rates for the Alpine Standard Vegetation transplanted to lower altitudes and slight

  10. A ten-year water balance of a mountainous semi-arid watershed

    NASA Astrophysics Data System (ADS)

    Flerchinger, G. N.; Cooley, K. R.

    2000-10-01

    Quantifying water balance components, which is particularly challenging in snow-fed, semi-arid regions, is crucial to understanding the basic hydrology of a watershed. In this study, a water balance was computed using 10 years of data collected at the Upper Sheep Creek Watershed, a 26-ha semi-arid mountainous sub-basin within the Reynolds Creek Experimental Watershed in southwest Idaho, USA. The approach computed a partial water balance for each of three landscape units and then computed an aggregated water balance for the watershed. Runoff and change in ground water storage were not distinguishable between landscape units. Precipitation, which occurs predominantly as snow, was measured within each landscape unit directly and adjusted for drifting. Spatial variability of effective precipitation was shown to be greater during years with higher precipitation. Evapotranspiration, which accounted for nearly 90% of the effective precipitation, was estimated using the Simultaneous Heat and Water (SHAW) Model and validated with measurements from Bowen ratio instruments. Runoff from the watershed was correlated to precipitation above a critical threshold of approximately 450 mm of precipitation necessary to generate runoff ( r2=0.52). The average water balance error was 46 mm, or approximately 10% of the estimated effective precipitation for the ten-year period. The error was largely attributed to deep percolation losses through fractures in the basalt underlying the watershed. Simulated percolation of the water beyond the root zone correlated extremely well with measured runoff ( r2=0.90), which is derived almost entirely from subsurface flow. Above a threshold of 50 mm, approximately 67% of the water percolating beyond the root zone produces runoff. The remainder was assumed to be lost to deep percolation through the basalt. This can have important ramifications in addressing subsurface flow and losses when applying a snowmelt runoff model to simulate runoff and

  11. Water and energy balance in a Mediterranean snowpack: the importance of evaposublimation

    NASA Astrophysics Data System (ADS)

    Herrero, Javier; Pimentel, Rafael; María José, Pérez-Palazón; María José, Polo

    2016-04-01

    In low-latitude snowpacks or those located in semiarid regions, snow dynamics becomes an essential driver of the hydrological cycle, as well as an important support for a number of ecosystem services with an influence over the economy and the ecology of the whole region. Therefore, it is crucial to understand the processes that are taking place in the snowpack and the relative importance and timing of the different mass and energy fluxes. Sierra Nevada is a linear mountain range parallel to the Mediterranean coastline of southern Spain at 37°N. It reaches up to 3479 m.a.s.l. in approximately 40 km from the sea. Despite the semiarid climatic conditions that surround the high mountain area, it presents a regular snow cover above 2500 m.a.s.l. during the winter season. Previous studies have shown at this site that this snowpack is very exposed to high insolation rates and strong winds, and, like in other low-latitude areas, the radiative and evaposublimation (combination of the sublimation of ice and the evaporation of the water drops melted on the surface of the snow) fluxes may have a significant and prominent value in the coupled balance. In this work, we study the evaposublimation fraction in the annual water and energy balance over the snowpack in Sierra Nevada. For this, we apply a one-layer mass and energy balance snow model developed in previous works, which has proven to adequately simulate the shallow snowpacks of Sierra Nevada during the year. High evaposublimation rates were simulated and subsequently measured during several field campaigns. Evaposublimation fractions were found to range from 24 to 33% of the total annual ablation at this site. This ratio is very changeable between years, like the local meteorology itself, even though there was not a direct relationship between this rate and the dry or humid nature of each particular year. In fact, it is the particular distribution of the rainfall throughout the year what defines the dynamics of the

  12. Comparative Modeling Studies of Boreal Water and Carbon Balance

    NASA Technical Reports Server (NTRS)

    Coughlan, J.; Peterson, David L. (Technical Monitor)

    1997-01-01

    The coordination of the modeling and field efforts for an Intensive Field Campaign (IFC) may resemble the chicken and egg dilemma. This session's theme advocates that early and proactive involvement by modeling teams can produce a scientific and operational benefit for the IFC and Experiment. This talk will provide some examples and suggestions originating from the NASA funded IFC's of the FIFE First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment, Oregon Transect Ecosystem Research (OTTER) and predominately Boreal Ecosystem-Atmosphere Study (BOREAS) Experiments. In February 1994 and prior to the final selection of the BOREAS study sites, a group of funded BOREAS investigators agreed to run their models with data for five community types representing the proposed tower flux sites. All participating models were given identical initial values and boundary conditions and driven with identical climate data. The objectives of the intercomparison exercise were: 1) compare simulation results of participating terrestrial, hydrological, and atmospheric models over selected time frames; 2) learn about model behavior and sensitivity to estimated boreal site and vegetation definitions; 3) prioritize BOREAS field data collection efforts supporting modeling studies; 4) identify individual model deficiencies as early as possible. Out of these objectives evolved some important coordination and science issues for the BOREAS Experiment that can be generalized to IFCs and long term archiving of the data. Some problems are acceptable because they are endemic to maintaining fair and open competition prior to the peer review process. Others are logistical and addressable through application of planning, management, and information sciences. This investigator has identified one source of measurement and model incompatibility that is manifest in the IFC scaling approach. Although intuitively obvious, scaling problems are already more formally defined in

  13. Condensing Hybrid Water Heater Monitoring Field Evaluation

    SciTech Connect

    Maguire, J.; Earle, L.; Booten, C.; Hancock, C. E.

    2011-10-01

    This paper summarizes the Mascot home, an abandoned property that was extensively renovated. Several efficiency upgrades were integrated into this home, of particular interest, a unique water heater (a Navien CR240-A). Field monitoring was performed to determine the in-use efficiency of the hybrid condensing water heater. The results were compared to the unit's rated efficiency. This unit is Energy Star qualified and one of the most efficient gas water heaters currently available on the market.

  14. Cyber-physical system for a water reclamation plant: Balancing aeration, energy, and water quality to maintain process resilience

    NASA Astrophysics Data System (ADS)

    Zhu, Junjie

    Aeration accounts for a large fraction of energy consumption in conventional water reclamation plants (WRPs). Although process operations at older WRPs can satisfy effluent permit requirements, they typically operate with excess aeration. More effective process controls at older WRPs can be challenging as operators work to balance higher energy costs and more stringent effluent limitations while managing fluctuating loads. Therefore, understandings of process resilience or ability to quickly return to original operation conditions at a WRP are important. A state-of-art WRP should maintain process resilience to deal with different kinds of perturbations even after optimization of energy demands. This work was to evaluate the applicability and feasibility of cyber-physical system (CPS) for improving operation at Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) Calumet WRP. In this work, a process model was developed and used to better understand the conditions of current Calumet WRP, with additional valuable information from two dissolved oxygen field measurements. Meanwhile, a classification system was developed to reveal the pattern of historical influent scenario based on cluster analysis and cross-tabulation analysis. Based on the results from the classification, typical process control options were investigated. To ensure the feasibility of information acquisition, the reliability and flexibility of soft sensors were assessed to typical influent conditions. Finally, the process resilience was investigated to better balance influent perturbations, energy demands, and effluent quality for long-term operations. These investigations and evaluations show that although the energy demands change as the influent conditions and process controls. In general, aeration savings could be up to 50% from the level of current consumption; with a more complex process controls, the saving could be up to 70% in relatively steady-state conditions and at least 40

  15. Estimating basin scale evapotranspiration (ET) by water balance and remote sensing methods

    USGS Publications Warehouse

    Senay, G.B.; Leake, S.; Nagler, P.L.; Artan, G.; Dickinson, J.; Cordova, J.T.; Glenn, E.P.

    2011-01-01

    Evapotranspiration (ET) is an important hydrological process that can be studied and estimated at multiple spatial scales ranging from a leaf to a river basin. We present a review of methods in estimating basin scale ET and its applications in understanding basin water balance dynamics. The review focuses on two aspects of ET: (i) how the basin scale water balance approach is used to estimate ET; and (ii) how ‘direct’ measurement and modelling approaches are used to estimate basin scale ET. Obviously, the basin water balance-based ET requires the availability of good precipitation and discharge data to calculate ET as a residual on longer time scales (annual) where net storage changes are assumed to be negligible. ET estimated from such a basin water balance principle is generally used for validating the performance of ET models. On the other hand, many of the direct estimation methods involve the use of remotely sensed data to estimate spatially explicit ET and use basin-wide averaging to estimate basin scale ET. The direct methods can be grouped into soil moisture balance modelling, satellite-based vegetation index methods, and methods based on satellite land surface temperature measurements that convert potential ET into actual ET using a proportionality relationship. The review also includes the use of complementary ET estimation principles for large area applications. The review identifies the need to compare and evaluate the different ET approaches using standard data sets in basins covering different hydro-climatic regions of the world.

  16. Aestivation and diapause syndromes reduce the water balance requirements for pupae of the Hessian fly, Mayetiola destructor.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We report the water balance of aestivating (summer), diapausing (winter), and non-diapausing pupae of Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae). Maintaining water requirements during pupal dormancy is particularly important because water cannot be replenished actively by drink...

  17. Increased fat catabolism sustains water balance during fasting in zebra finches.

    PubMed

    Rutkowska, Joanna; Sadowska, Edyta T; Cichoń, Mariusz; Bauchinger, Ulf

    2016-09-01

    Patterns of physiological flexibility in response to fasting are well established, but much less is known about the contribution of water deprivation to the observed effects. We investigated body composition and energy and water budget in three groups of zebra finches: birds with access to food and water, food-deprived birds having access to drinking water and food-and-water-deprived birds. Animals were not stimulated by elevated energy expenditure and they were in thermoneutral conditions; thus, based on previous studies, water balance of fasting birds was expected to be maintained by increased catabolism of proteins. In contrast to this expectation, we found that access to water did not prevent reduction of proteinaceous tissue, but it saved fat reserves of the fasting birds. Thus, water balance of birds fasting without access to water seemed to be maintained by elevated fat catabolism, which generated 6 times more metabolic water compared with that in birds that had access to water. Therefore, we revise currently established views and propose fat to serve as the primary source for metabolic water production. Previously assumed increased protein breakdown for maintenance of water budget would occur if fat stores were depleted or if fat catabolism reached its upper limits due to high energy demands. PMID:27582561

  18. Impact of spatial data resolution on simulated catchment water balances and model performance of the multi-scale TOPLATS model

    NASA Astrophysics Data System (ADS)

    Bormann, H.

    2006-03-01

    This paper analyses the effect of spatial input data resolution on the simulated water balances and flow components using the multi-scale hydrological model TOPLATS. A data set of 25m resolution of the central German Dill catchment (693 km2) is used for investigation. After an aggregation of digital elevation model, soil map and land use classification to 50 m, 75 m, 100 m, 150 m, 200 m, 300 m, 500 m, 1000 m and 2000 m, water balances and water flow components are calculated for the entire Dill catchment as well as for 3 subcatchments without any recalibration. The study shows that model performance measures and simulated water balances almost remain constant for most of the aggregation steps for all investigated catchments. Slight differences in the simulated water balances and statistical quality measures occur for single catchments at the resolution of 50 m to 500 m (e.g. 0-3% for annual stream flow), significant differences at the resolution of 1000 m and 2000 m (e.g. 2-12% for annual stream flow). These differences can be explained by the fact that the statistics of certain input data (land use data in particular as well as soil physical characteristics) changes significantly at these spatial resolutions. The impact of smoothing the relief by aggregation occurs continuously but is barely reflected by the simulation results. To study the effect of aggregation of land use data in detail, in addition to current land use the effect of aggregation on the water balance calculations based on three different land use scenarios is investigated. Land use scenarios were available aiming on economic optimisation of agricultural and forestry practices at different field sizes (0.5 ha, 1.5 ha and 5.0 ha). The changes in water balance terms, induced by aggregation of the land use scenarios, are comparable with respect to catchment water balances compared to the current land use. A correlation analysis between statistics of input data and simulated annual water fluxes only in

  19. Life in the Treetops: Drought Tolerance and Water Balance of Canopy Epiphytes in a Tropical Montane Cloud Forest

    NASA Astrophysics Data System (ADS)

    Gotsch, S. G.; Nadkarni, N.; Darby, A.; Dix, M.; Glunk, A.; Davidson, K.; Dawson, T. E.

    2014-12-01

    Tropical montane cloud forests (TMCFs) inhabit regions rich in biodiversity that play an important role in the local and regional water cycle. Canopy plants such as epiphytes and hemiepiphytes are an important component of the biodiversity in the TMCF and therefore play a significant role in the carbon, nutrient and water cycles. With only partial or no access to resources on the ground, canopy plants may be vulnerable to changes in climate that increase canopy temperatures and decrease atmospheric humidity or precipitation inputs. Despite their importance in the TMCF, there is little information regarding drought tolerance and water balance in this community. In this study we quantified variation in functional traits and water relations in 12 species of epiphytes and hemiepiphytes in a Costa Rican TMCF. We also generated pressure-volume curves and xylem vulnerability curves that we used as indicators of drought tolerance. Lastly, we determined the capacity for foliar water uptake in the laboratory and measured whole-plant transpiration in the field. We found that all species had a high turgor loss point (ψTLP), high vulnerability to cavitation (P50), and low bulk elastic modulus (ɛmax, i.e. high cell wall elasticity). These results indicate that capacitance may be high in canopy plants and that stored water may help to maintain high leaf water potentials during dry periods. We also found that all species had the capacity for foliar uptake and that this process contributed substantially to their water status and water balance. On average, foliar uptake contributed to the reabsorption of 70% of the water transpired over a 34-day period at the beginning of the dry season. Our results indicate that canopy plants can mitigate water loss substantially, but they may be vulnerable to changes in the overall precipitation patterns or increases in cloud base heights.

  20. Field Monitoring Protocol. Heat Pump Water Heaters

    SciTech Connect

    Sparn, B.; Earle, L.; Christensen, D.; Maguire, J.; Wilson, E.; Hancock, C. E.

    2013-02-01

    This document provides a standard field monitoring protocol for evaluating the installed performance of Heat Pump Water Heaters in residential buildings. The report is organized to be consistent with the chronology of field test planning and execution. Research questions are identified first, followed by a discussion of analysis methods, and then the details of measuring the required information are laid out. A field validation of the protocol at a house near the NREL campus is included for reference.

  1. Field Monitoring Protocol: Heat Pump Water Heaters

    SciTech Connect

    Sparn, B.; Earle, L.; Christensen, D.; Maguire, J.; Wilson, E.; Hancock, E.

    2013-02-01

    This document provides a standard field monitoring protocol for evaluating the installed performance of Heat Pump Water Heaters in residential buildings. The report is organized to be consistent with the chronology of field test planning and execution. Research questions are identified first, followed by a discussion of analysis methods, and then the details of measuring the required information are laid out. A field validation of the protocol at a house near the NREL campus is included for reference.

  2. Evaluation of military field-water quality

    SciTech Connect

    Daniels, J.I.; Gallegos, G.M.

    1990-05-01

    This is the first and summary volume of the nine-volume study entitled Evaluation of Military Field-Water Quality. This study is a comprehensive assessment of the chemical, radiological, and biological constituents of field-water supplied that could pose health risks to military personnel around the world; it also provides a detailed evaluation of the field-water-treatment capability of the US Armed Forces. This study identifies as being of concern three physical properties, i.e., turbidity, color, and total dissolved solids; seven chemical constituents, i.e., chloride, magnesium, sulfate, arsenic, cyanide, lindane, and metabolites of algae and associated aquatic bacteria; and over twenty types of water-related pathogenic microorganisms. It also addresses five threat agents, i.e., hydrogen cyanide, radioactivity, organophosphorous nerve agents, the trichotecene mycotoxin T-2, and lewisite. An overview of the criteria and recommendations for standards for these constituents for short- term and long-term exposure periods are presented in this volume, as are health-effects summaries for assessing the potential soldier performance degradation when recommended standards are exceeded. In addition, the existing military field-water-treatment capability is reviewed, and an abbreviated discussion is presented of the general physical, chemical, and biological qualities of field waters in geographic regions worldwide, representing potential theaters of operation for US military forces. Finally, research recommendations are outlined. 18 figs., 6 tabs.

  3. New interpretation of the role of water balance in an extended Budyko hypothesis in arid regions

    NASA Astrophysics Data System (ADS)

    Du, C.; Sun, F.; Yu, J.; Liu, X.; Chen, Y.

    2016-01-01

    The Budyko hypothesis (BH) is an effective approach to investigating long-term water balance at large basin scale under steady state. The assumption of steady state prevents applications of the BH to basins, which is unclosed, or with significant variations in root zone water storage, i.e., under unsteady state, such as in extremely arid regions. In this study, we choose the Heihe River basin (HRB) in China, an extremely arid inland basin, as the study area. We firstly use a calibrated and then validated monthly water balance model, i.e., the abcd model, to quantitatively determine annual and monthly variations of water balance for the sub-basins and the whole catchment of the HRB, and find that the roles of root zone water storage change and that of inflow from upper sub-basins in monthly water balance are significant. With the recognition of the inflow water from other regions and the root zone water storage change as additional possible water sources to evapotranspiration in unclosed basins, we further define the equivalent precipitation (Pe) to include local precipitation, inflow water and root zone water storage change as the water supply in the Budyko framework. With the newly defined water supply, the Budyko curve can successfully describe the relationship between the evapotranspiration ratio and the aridity index at both annual and monthly timescales, whilst it fails when only the local precipitation being considered. Adding to that, we develop a new Fu-type Budyko equation with two non-dimensional parameters (ω and λ) based on the deviation of Fu's equation. Over the annual timescale, the new Fu-type Budyko equation developed here has more or less identical performance to Fu's original equation for the sub-basins and the whole catchment. However, over the monthly timescale, due to large seasonality of root zone water storage and inflow water, the new Fu-type Budyko equation generally performs better than Fu's original equation. The new Fu-type Budyko

  4. Balancing water, religion and tourism on Redang Island, Malaysia

    NASA Astrophysics Data System (ADS)

    Fisher, Joshua B.; Nawaz, Rizwan; Fauzi, Rosmadi; Nawaz, Faiza; Sadek, Eran Sadek Said Md; Abd Latif, Zulkiflee; Blackett, Matthew

    2008-04-01

    Redang Island (Pulau Redang) is an island off of Peninsular Malaysia that is part of a Marine Park archipelago of corals and thousands of fish and invertebrates. The relatively isolated local community is generally centered on fishing, and Islam guides daily life. Recently, the tourism industry has expanded on the island. New hotels and resorts provide jobs, but also expose the locals to western culture and touristic behavior, which may clash with deeply traditional community values. Further, the tourism industry may be putting a strain on the natural resources, especially the quantity and quality of freshwater. The island village may become divided between those who support the tourism industry and those who do not. Here we present an exploratory investigation into the development environment culture dynamics of tourism, water and religion on Redang Island while building collaborations between universities of this Muslim state and the West.

  5. Norway's historical and projected water balance in TWh

    NASA Astrophysics Data System (ADS)

    Haddeland, Ingjerd; Holmqvist, Erik

    2015-04-01

    Hydroelectric power production is closely linked to the water cycle, and variations in power production numbers reflect variations in weather. The expected climate changes will influence electricity supply through changes in annual and seasonal inflow of water to hydropower reservoirs. In Norway, more than 95 percent of the electricity production is from hydroelectric plants, and industry linked to hydropower has been an important part of the society for more than a century. Reliable information on historical and future available water resources is hence of crucial importance both for short and long-term planning and adaptation purposes in the hydropower sector. Traditionally, the Multi-area Power-market Simulator (EMPS) is used for modelling hydropower production in Norway. However, due to the models' high level of details and computational demand, this model is only used for historical analyses and a limited number of climate projections. A method has been developed that transfers water fluxes (mm day-1) and states (mm) into energy units (GWh mm-1), based on hydrological modelling of a limited number of catchments representing reservoir inflow to more than 700 hydropower plants in Norway. The advantages of using the conversion factor method, compared to EMPS, are its simplicity and low computational requirements. The main disadvantages are that it does not take into account flood losses and the time lag between inflow and power production. The method is used operationally for weekly and seasonal energy forecasts, and has proven successful at the range of results obtained for reproducing historical hydropower production numbers. In hydropower energy units, mean annual precipitation for the period 1981-2010 is estimated at 154 TWh year-1. On average, 24 TWh year-1 is lost through evapotranspiration, meaning runoff equals 130 TWh year-1. There are large interannual variations, and runoff available for power production ranges from 91 to 165 TWh year-1. The snow pack

  6. Assessing the water balance of the Upper Rhine Graben hydrosystem

    NASA Astrophysics Data System (ADS)

    Thierion, Charlotte; Longuevergne, Laurent; Habets, Florence; Ledoux, Emmanuel; Ackerer, Philippe; Majdalani, Samer; Leblois, Etienne; Lecluse, Simon; Martin, Eric; Queguiner, Solen; Viennot, Pascal

    2012-03-01

    SummaryThe Upper Rhine alluvial aquifer is an important transboundary water resource. However, as in many alluvial systems, the aquifer inflows and outflows are not precisely known because of the difficulty of estimating the river infiltration flux and the boundary subsurface flow. To provide a thorough representation of the aquifer system, a coupled surface-subsurface model was applied to the whole aquifer basin, and several parameter sets were tested to investigate the uncertainty due to poorly known parameters (e.g. aquifer transmissivity computed by an inverse model, river bed characteristics). Twelve simulations were run and analyzed using standard statistical criteria and also a more advanced statistical method, the Karhunen Loève transform (KLT). This analysis showed that, although the model performed reasonably well, some piezometric level underestimations persisted in the south of the basin. An accurate representation of the aquifer behaviour would require river infiltration and the functioning of irrigation canals in the Hardt area to be taken into account. It also appeared that increasing the maximum river infiltration flow deteriorated the quality of the results. River infiltration to the aquifer was estimated to represent about 80% of the aquifer inflows with a mean annual value around 115 ± 16.5 m3/s, thus with an uncertainty of 14%. This quantity is larger than estimated in previous studies but is in agreement with some results obtained during low water periods. This important conclusion highlights the vulnerability of the Upper Rhine Graben aquifer to pollution from the rivers and to climate change since it is highly probable that the rivers' regimes will be affected by reduced snow cover on the neighbouring mountain ranges.

  7. New interpretation of the role of water balance in an extended Budyko hypothesis in arid regions

    NASA Astrophysics Data System (ADS)

    Du, C.; Sun, F.; Yu, J.; Liu, X.; Chen, Y.

    2015-10-01

    The Budyko hypothesis (BH) is an effective approach to investigating long-term water balance at large basin scale under steady state. The assumption of steady state prevents applications of the BH to basins, which is unclosed, or with significant variations in soil water storage, i.e., under unsteady state, such as in extremely arid regions. In this study, we choose the Heihe River Basin (HRB) in China, an extremely arid inland basin, as the study area. We firstly use a calibrated and then validated monthly water balance model, i.e., the abcd model to quantitatively determine annual and monthly variations of water balance for the sub-basins and the whole catchment of the HRB and find that the role of soil water storage change and that of inflow from upper sub-basins in monthly water balance are significant. With the recognition of the inflow water from other regions and the soil water storage change as additional possible water sources to evapotranspiration in unclosed basins, we further define the equivalent precipitation (Pe) to include local precipitation, inflow water and soil water storage change as the water supply in the Budyko framework. With the newly defined water supply, the Budyko curve can successfully describe the relationship between the evapotranspiration ratio and the aridity index at both annual and monthly timescales, whilst it fails when only the local precipitation being considered. Adding to that, we develop a new Fu-type Budyko equation with two non-dimensional parameters (ω and λ) based on the deviation of Fu's equation. Over the annual time scale, the new Fu-type Budyko equation developed here has more or less identical performance to Fu's original equation for the sub-basins and the whole catchment. However, over the monthly time scale, due to large seasonality of soil water storage and inflow, the new Fu-type Budyko equation generally performs better than Fu's original equation. The new Fu-type Budyko equation (ω and λ) developed here

  8. Optimization of water balance within the martian crew life support system

    NASA Astrophysics Data System (ADS)

    Sychev, V.; Levinskikh, M.

    The present-day scenarios of the first exploration mission differ in the total length crew size period of the stay on Mars etc However no matter the scenario one of the common problems is optimization of water balance within the crew life support system Water balance optimization implies in addition to regeneration of atmospheric moisture and urine also dehydration of biowastes In this mission all wastes will be stored and for this reason safe storage is prerequisite Investigations of two-component laboratory BLSS in which the autotrophic component was composed of algae Spirulina platensis and the heterotrophic component was represented by Japanese quail Coturnix coturnix japonica dom showed that optimization of the autotrophic and heterotrophic gas exchange and water regeneration from quail biowastes could raise the system susbstance balance to 76 of the total balance during autonomic cultivation of algae and birds In these investigations dehydration of quail biowastes caused significant pollution of water and air by organics toxic for humans It was demonstrated that the sorption technologies applied on the Russian space station MIR and ISS cannot fully absorb organic contaminants released in the process of quail wastes drying Algal suspension as a hydrobiological filter was able to control the organic pollination of both air and water These results are in agreement with the data of ground-based simulation studies with participation of human subjects at IBMP According to the simulation data intensive

  9. The efficacy of combining satellite water storage and soil moisture observations as constraints on water balance estimation

    NASA Astrophysics Data System (ADS)

    Tian, Siyuan; van Dijk, Albert; Renzullo, Luigi; Tregoning, Paul; Walker, Jeffrey; Pauwels, Valentijn

    2016-04-01

    The ability to accurately estimate terrestrial water storage (TWS) and its components (e.g. soil moisture, groundwater, surface water and snow) is of considerable value to water resources assessment. Due to the imperfection of both model predictions and observations, data assimilation methods have been widely applied to hydrological problems for optimal combination of model and observations. Recent studies on the assimilation of TWS data have shown its capability to improve simulated groundwater storages, but the assimilation of TWS only does not guarantee accurate estimation of surface soil moisture (SSM). We investigated the efficiency of data assimilation combining TWS change estimates, derived from temporal changes in Earth's gravity field measured by the Gravity Recovery and Climate Experiment (GRACE), with SSM, retrieved from emitted microwave radiation at L-band observed by the Soil Moisture and Ocean Salinity (SMOS) satellite. The global World Wide Water (W3) water balance model was used. The specific satellite data products used were the SMOS CATDS level 3 daily SSM product and the JPL mascon monthly GRACE product. Both the ensemble Kalman filter (EnKF) and smoother (EnKS) were implemented to determine the best option for the assimilation of SSM observations only and the joint assimilation of SSM and TWS. The observation models, which map model states into observation space, are the top-layer soil relative wetness and monthly average TWS (i.e. aggregated daily top-, shallow-, deep-layer soil water storage, ground- and surface water storages). Three assimilation experiments were conducted with each method: a) assimilation of SSM data only; b) assimilation of TWS data only; c) joint assimilation of SSM and TWS data. Results were compared against in-situ soil moisture and groundwater observations, and the performance assessed with respect to open-loop results. Results for the Murray-Darling Basin in Australia demonstrate that the assimilation of SSM data only

  10. Effects of rainfall seasonality and soil moisture capacity on mean annual water balance for Australian catchments

    USGS Publications Warehouse

    Potter, N.J.; Zhang, L.; Milly, P.C.D.; McMahon, T.A.; Jakeman, A.J.

    2005-01-01

    An important factor controlling catchment-scale water balance is the seasonal variation of climate. The aim of this study is to investigate the effect of the seasonal distributions of water and energy, and their interactions with the soil moisture store, on mean annual water balance in Australia at catchment scales using a stochastic model of soil moisture balance with seasonally varying forcing. The rainfall regime at 262 catchments around Australia was modeled as a Poisson process with the mean storm arrival rate and the mean storm depth varying throughout the year as cosine curves with annual periods. The soil moisture dynamics were represented by use of a single, finite water store having infinite infiltration capacity, and the potential evapotranspiration rate was modeled as an annual cosine curve. The mean annual water budget was calculated numerically using a Monte Carlo simulation. The model predicted that for a given level of climatic aridity the ratio of mean annual evapotranspiration to rainfall was larger where the potential evapotranspiration and rainfall were in phase, that is, in summer-dominant rainfall catchments, than where they were out of phase. The observed mean annual evapotranspiration ratios have opposite results. As a result, estimates of mean annual evapotranspiration from the model compared poorly with observational data. Because the inclusion of seasonally varying forcing alone was not sufficient to explain variability in the mean annual water balance, other catchment properties may play a role. Further analysis showed that the water balance was highly sensitive to the catchment-scale soil moisture capacity. Calibrations of this parameter indicated that infiltration-excess runoff might be an important process, especially for the summer-dominant rainfall catchments; most similar studies have shown that modeling of infiltration-excess runoff is not required at the mean annual timescale. Copyright 2005 by the American Geophysical Union.

  11. Impact of spatial data resolution on simulated catchment water balances and model performance of the multi-scale TOPLATS model

    NASA Astrophysics Data System (ADS)

    Bormann, H.

    2005-10-01

    This paper analyses the effect of spatial input data resolution on the simulated water balances and flow components using the multi-scale hydrological model TOPLATS. A data set of 25m resolution of the central German Dill catchment (693 km2 is used for investigation. After an aggregation of digital elevation model, soil map and land use classification to 50 m, 75 m, 100 m, 150 m, 200 m, 300 m, 500 m, 1000 m and 2000 m, water balances and water flow components are calculated for the entire Dill catchment as well as for 3 subcatchments without any recalibration. The study shows that both model performance measures as well as simulated water balances almost remain constant for most of the aggregation steps for all investigated catchments. Slight differences occur for single catchments at the resolution of 50-500 m (e.g. 0-3% for annual stream flow), significant differences at the resolution of 1000 m and 2000 m (e.g. 2-12% for annual stream flow). These differences can be explained by the fact that the statistics of certain input data (land use data in particular as well as soil physical characteristics) changes significantly at these spatial resolutions, too. The impact of smoothing the relief by aggregation occurs continuously but is not reflected by the simulation results. To study the effect of aggregation of land use data in detail, three different land use scenarios are aggregated which were generated aiming on economic optimisation at different field sizes (0.5 ha, 1.5 ha and 5.0 ha). The changes induced by aggregation of these land use scenarios are comparable with respect to catchment water balances compared to the current land use. A correlation analysis only in some cases reveals high correlation between changes in both input data and in simulation results for all catchments and land use scenarios combinations (e.g. evapotranspiration is correlated to land use, runoff generation is correlated to soil properties). Predominantly the correlation between

  12. Vascular functioning and the water balance of ripening kiwifruit (Actinidia chinensis) berries

    PubMed Central

    Clearwater, Michael J.; Luo, Zhiwei; Ong, Sam Eng Chye; Blattmann, Peter; Thorp, T. Grant

    2012-01-01

    Indirect evidence suggests that water supply to fleshy fruits during the final stages of development occurs through the phloem, with the xylem providing little water, or acting as a pathway for water loss back to the plant. This inference was tested by examining the water balance and vascular functioning of ripening kiwifruit berries (Actinidia chinensis var. chinensis ‘Hort16A’) exhibiting a pre-harvest ‘shrivel’ disorder in California, and normal development in New Zealand. Dye labelling and mass balance experiments indicated that the xylem and phloem were both functional and contributed approximately equally to the fruit water supply during this stage of development. The modelled fruit water balance was dominated by transpiration, with net water loss under high vapour pressure deficit (Da) conditions in California, but a net gain under cooler New Zealand conditions. Direct measurement of pedicel sap flow under controlled conditions confirmed inward flows in both the phloem and xylem under conditions of both low and high Da. Phloem flows were required for growth, with gradual recovery after a step increase in Da. Xylem flows alone were unable to support growth, but did supply transpiration and were responsive to Da-induced pressure fluctuations. The results suggest that the shrivel disorder was a consequence of a high fruit transpiration rate, and that the perception of complete loss or reversal of inward xylem flows in ripening fruits should be re-examined. PMID:22155631

  13. Water balance in irrigation districts. Uncertainty in on-demand pressurized networks

    NASA Astrophysics Data System (ADS)

    Sánchez-Calvo, Raúl; Rodríguez-Sinobas, Leonor; Juana, Luis; Laguna, Francisco Vicente

    2015-04-01

    In on-demand pressurized irrigation distribution networks, applied water volume is usually controlled opening a valve during a calculated time interval, and assuming constant flow rate. In general, pressure regulating devices for controlling the discharged flow rate by irrigation units are needed due to the variability of pressure conditions. A pressure regulating valve PRV is the commonly used pressure regulating device in a hydrant, which, also, executes the open and close function. A hydrant feeds several irrigation units, requiring a wide range in flow rate. In addition, some flow meters are also available, one as a component of the hydrant and the rest are placed downstream. Every land owner has one flow meter for each group of field plots downstream the hydrant. Ideal PRV performance would maintain a constant downstream pressure. However, the true performance depends on both upstream pressure and the discharged flow rate. Theoretical flow rates values have been introduced into a PRV behavioral model, validated in laboratory, coupled with an on-demand irrigation district waterworks, composed by a distribution network and a multi-pump station. Variations on flow rate are simulated by taking into account the consequences of variations on climate conditions and also decisions in irrigation operation, such us duration and frequency application. The model comprises continuity, dynamic and energy equations of the components of both the PRV and the water distribution network. In this work the estimation of water balance terms during the irrigation events in an irrigation campaign has been simulated. The effect of demand concentration peaks has been estimated.

  14. Evaluation of water and energy balances ovet the Colombian Orinoco Catchment Basin

    NASA Astrophysics Data System (ADS)

    Abril, C.; Baquero-Bernal, A.

    2012-04-01

    This study presents a comparison between in-situ observations and gridded data from reanalyses and from a regional climate model over the Colombian Orinoco Catchment Basin, in South America, with focus on the surface water and energy balances. We use datasets from the regional climate model REMO and re-analyses ERA40, ERAInterim and NCEP/NCAR. The in-situ observations have been provided by the Colombian Institute of Hydrology, Meteorology and Environmental Studies (IDEAM). The balances are for the 1958-2011 period. Statistical analyses of temperature and precipitation are also presented. Discrepancies between gridded datasets and observations are evaluated and possible sources of error in each of the datasets are discussed. The research presented is the first intercomparison of the surface water and energy balances over the Colombian Orinoco Catchment Basin from different datasets.

  15. Water balance indicators from MODIS images and agrometeorological data in Minas Gerais state, Brazil

    NASA Astrophysics Data System (ADS)

    de C. Teixeira, Antônio H.; Leivas, Janice F.; Andrade, Ricardo G.; de C. Victoria, Daniel; Bolfe, Edson L.; da Silva, Gustavo B. S.

    2015-10-01

    Minas Gerais state, Brazil, has experienced severe water scarcity in some areas, demanding large-scale water balance studies to subsidize water policies. The reflectance bands from the MOD13Q1 MODIS product were used together with gridded agrometeorological data in the state, during the year 2014, later extracting the main agriculture growing regions, North, Northwest and Minas Triangle, for analyzes. Precipitation (Prec) and reference evapotranspiration (ET0) data from 36 weather stations were interpolated, while for actual evapotranspiration (ET), the SAFER (Simple Algorithm for Evapotranspiration Retrieving) algorithm was used. Two climatic water balance indicators were applied, the Water Balance Ratio (WBr = Prec/ET) and the Water Balance Difference (WDd = Prec - ET). The daily net radiation (Rn) was retrieved from surface albedo (α0), air temperature (Ta) and shortwave atmospheric transmissivity (τsw), while the ground heat flux (G) was estimated as a fraction of Rn. For surface moisture, the evapotranspiration ratio (ETr = ET/ET0) and the evaporative fraction [Ef = λE/(Rn - G)] were used, with the latent heat flux (λE) obtained by transforming ET into energy units. Analyzing WDr and WDd, the most water scarcity critical MODIS 16-day periods, reaching to minimum values lower than 1.0 and -10 mm, respectively, were from the end of April to the middle of October. Higher water availability, detected by these indicators larger than 1.5 and 10 mm, respectively, were from the middle of October to the end of December. The maximums WDr and WDd of 7.0 and 158 mm happened from the middle of November to the start of December in the Northwest agricultural growing region. However, according to the ETr and Ef values, after this period, the soil moisture storage showed a gap, increasing only in the second half of December, when they reached to averages of 0.63. The largest values of these last soil moisture indicators, above 0.70 in May, did not coincided with the period

  16. The observed evapotranspiration combining the energy and water balance for different land use under semiarid Mediterranean catchment

    NASA Astrophysics Data System (ADS)

    Zitouna Chebbi, Rim; Mekki, Insaf; Jacob, Frédéric; Masmoudi, Moncef; Prévot, Laurent; Ben Mechlia, Netij; Voltz, Marc; Albergel, Jean

    2014-05-01

    The Mediterranean semiarid cultivated catchments are affected by global and climate change and are characterized by very complex hydrological systems. The improvement of their management requires a best understanding of the hydrological processes and developing reliable means for characterizing the temporal dynamics of soil water balance in a spatially distributed manner. The main objective of this study is: i) to analyze the observed evapotranspiration in relation to natural drivers (i.e. rainfall and soil properties) and anthropogenic forcing (i.e. land use and crop successions), and ) ii to assess the differences in both energy and water balances. We focus on a hilly semiarid Mediterranean catchment devoted to rainfed agriculture, so-called the Kamech catchment, which is located in the Cap Bon Peninsula, north-eastern Tunisia. The site belongs to the OMERE observatory for environmental research and it is monitored for the different hydrological cycle components under influence of anthropogenic forcing. The analysis is based on in-situ data measured under the common cereals/legumes/pasture cropping systems within the Kamech catchment. Energy and water balance components and vegetation parameters were collected in different fields and during various crop growth cycles. The results showed the highly variable response of energy and water balances depending on soil types, land use, and climatic conditions. The annual rainfall is mainly converted into evapotranspiration during the growing cycle for different land uses. The runoff amounts, for most of the sites, correspond to less than 10% of the rainfall amount. The evapotransipration ratios differed significantly across site and season in relation to soil properties and cumulated rainfall. We observe large differences in soil water dynamics among the legumes (fababean and chickpea) and cereals (wheat, oat, and triticale). Soil water is larger for legume crops, despite substantial plant growth during winter

  17. Soil moisture assimilation using a modified ensemble transform Kalman filter with water balance constraint

    NASA Astrophysics Data System (ADS)

    Wu, Guocan; Zheng, Xiaogu; Dan, Bo

    2016-04-01

    The shallow soil moisture observations are assimilated into Common Land Model (CoLM) to estimate the soil moisture in different layers. The forecast error is inflated to improve the analysis state accuracy and the water balance constraint is adopted to reduce the water budget residual in the assimilation procedure. The experiment results illustrate that the adaptive forecast error inflation can reduce the analysis error, while the proper inflation layer can be selected based on the -2log-likelihood function of the innovation statistic. The water balance constraint can result in reducing water budget residual substantially, at a low cost of assimilation accuracy loss. The assimilation scheme can be potentially applied to assimilate the remote sensing data.

  18. On the use of a water balance to evaluate inter-annual terrestrial ET variability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurately measuring inter-annual variability in terrestrial evapotranspiration (ET) is a major challenge for efforts to detect inter-annual variability in the hydrologic cycle. Based on comparisons with annual ET values derived from a terrestrial water balance analysis, past research has cast doubt...

  19. THE WATER BALANCE OF THE SUSQUEHANNA RIVER BASIN AND ITS RESPONSE TO CLIMATE CHANGE. (R824995)

    EPA Science Inventory

    Abstract

    Historical precipitation, temperature and streamflow data for the Susquehanna River Basin (SRB) are analyzed with the objective of developing simple statistical and water balance models of streamflow at the watershed's outlet. Annual streamflow is highly corre...

  20. Long-term water balance and conceptual model of a semi-arid mountainous catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term water balance investigations are needed to better understand hydrologic systems, especially semi-arid mountainous catchments. These systems exhibit considerable interannual variability in precipitation as well as spatial variation in snow accumulation, soils, and vegetation. This study e...

  1. REACTION PATHWAY OF THE DIKETONITRILE DEGRADATE OF ISOXAFLUTOLE (BALANCE(TM)) WITH HYPOCHLORITE IN WATER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isoxaflutole (IXF; Balance(TM)) belongs to the new class of isoxazole herbicides. Isoxaflutole has a very short half-life in soil and rapidly degrades to a stable and phytotoxic degradate, diketonitrile (DKN). DKN was previously discovered to rapidly react with hypochlorite (OCl-) in tap water, yie...

  2. The water balance components of undisturbed tropical woodlands in the Brazilian cerrado

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deforestation of the Brazilian cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood but are important for making land management decisions in this region. To better understand pre-deforestation conditions, we determi...

  3. Effects of increased CO2 on land water balance from 1850 to 1989

    NASA Astrophysics Data System (ADS)

    Peng, Jing; Dong, Wenjie; Yuan, Wenping; Chou, Jieming; Zhang, Yong; Li, Juan

    2013-02-01

    Numerous studies have shown that increased atmospheric CO2 concentration is one of the most important factors altering land water balance. In this study, we investigated the effects of increased CO2 on global land water balance using the dataset released by the Coupled Model Intercomparison Project Phase 5 derived from the Canadian Centre for Climate Modelling and Analysis second-generation Earth System Model. The results suggested that the radiative effect of CO2 was much greater than the physiological effect on the water balance. At the model experiment only integrating CO2 radiative effect, the precipitation, evapotranspiration (ET) and runoff had significantly increased by 0.37, 0.12 and 0.31 mm year-2, respectively. Increases of ET and runoff caused a significant decrease of soil water storage by 0.05 mm year-2. However, the results showed increases of runoff and decreases of precipitation and ET in response to the CO2 fertilisation effect, which resulted into a small, non-significant decrease in the land water budget. In the Northern Hemisphere, especially on the coasts of Greenland, Northern Asia and Alaska, there were obvious decreases of soil water responding to the CO2 radiative effect. This trend could result from increased ice-snow melting as a consequence of warmer surface temperature. Although the evidence suggested that variations in soil moisture and snow cover and vegetation feedback made an important contribution to the variations in the land water budget, the effect of other factors, such as aerosols, should not be ignored, implying that more efforts are needed to investigate the effects of these factors on the hydrological cycle and land water balance.

  4. Water balance and soil losses in an irrigated catchment under conservation tillage in Southern Spain

    NASA Astrophysics Data System (ADS)

    Cid, Patricio; Mateos, Luciano; Taguas, Encarnación V.; Gómez-Macpherson, Helena

    2013-04-01

    Conservation tillage based on permanent beds with crop-residue retention and controlled traffic has been recently introduced in irrigated annual crops in Southern Spain as one way to improve water infiltration, reduce soil losses, and save energy. The water balance and soil losses in water runoff have been monitored during 4 years in a 28-ha catchment within a production farm where this kind of soil conservation practice was established in 2004 for a maize-cotton-wheat rotation. The catchment average slope is 6 %. Soils are Typic Calcixerept and Typic Haploxerert. The water balance components that were measured include: applied irrigation water, rainfall, and runoff. Runoff was measured at the outlet of the catchment by means of a hydrological station that consisted of long-throated flume, ultrasonic water level sensor, automatic water sampler, data logger and transmission system, weather station, and ancillary equipment. We present here results from three hydrological seasons (October to September): 2009-10, 2010-11, and 2011-12. The first season the catchment was grown with wheat, thus the irrigation depth was small (25 mm); rainfall above average, 1103 mm; and the runoff coefficient was 26 %. In the season 2010-11, the catchment was grown with cotton, the irrigation depth was 503 mm, rainfall was 999 mm, and the seasonal runoff coefficient was 7 %. The last season, the crop was maize, rainfall was below average (368 mm), irrigation 590 mm, and the runoff coefficient as the previous year, 7 %. Soil losses were very small: 0.05, 1.26, and 1.33 t per ha and year, the first, second, and third monitored seasons, respectively. A simple water balance model allowed simulating evapotranspiration, deep percolation and runoff. The Curve Number for the catchment was calibrated using the balance model.

  5. ACCURACY OF PROJECT-WIDE WATER USES FROM A WATER BALANCE: A CASE STUDY FROM SOUTHERN CALIFORNIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A detailed water balance was conducted on the Imperial Valley in southern California for the years 1987 to 1996. The area included all lands within the boundaries defined, including farms, towns, road, etc. This analysis included surface and subsurface inflows, rainfall, surface and subsurface outfl...

  6. NIDWat: A Water Balance Model for the Niger Inland Delta (NID) Floodplain in Mali

    NASA Astrophysics Data System (ADS)

    Moussa, I.; Wisser, D.; Ali, A.; Seidou, O.; Mariko, A.; Afouda, A.

    2015-12-01

    The Niger river basin is characterized by hydro-climatic changes induced by land use and climate change that have significant impacts on local populations. The Niger Inland Delta (NID) is the single most important wetland conditioning the water availability downstream. A significant fraction of the river flow is lost through evaporation and water use in the NID and the conditions are likely to change with increasing population and changing inflow conditions. A comprehensive understanding of the NID's hydro-climatological functioning is therefore crucial for assessing the water resources in the basin under changing conditions in the future. Despite this significance, the components of the water balance in the NID are poorly quantified. We use optical and microwave remote sensing data to characterize the temporal flooding, and observations of river flow and spatially explicit information on water abstractions to develop NIDWat, a water balance model for the NID. Simulated evapotranspiration losses varied by ~ 50%, depending on flooded area map or climatic data. The combined effect of irrigation abstraction and climatic data generated a global water losses range of 16 to 33.04 km3 a-1. The model was validated against observed river discharge and water abstractions and shows a good performance. We then implemented the model as a module in a hydrological model to assess the water balance in the NID and the downstream water availability under changing conditions. We use a multi model approach using regional climate data from the CORDEX initiative. Results suggest, despite increasing runoff an increase in ET losses and changes in the temporal dynamics of flooding that impact water resources availability downstream.

  7. An analytical algorithm for 3D magnetic field mapping of a watt balance magnet

    NASA Astrophysics Data System (ADS)

    Fu, Zhuang; Zhang, Zhonghua; Li, Zhengkun; Zhao, Wei; Han, Bing; Lu, Yunfeng; Li, Shisong

    2016-04-01

    A yoke-based permanent magnet, which has been employed in many watt balances at national metrology institutes, is supposed to generate strong and uniform magnetic field in an air gap in the radial direction. However, in reality the fringe effect due to the finite height of the air gap will introduce an undesired vertical magnetic component to the air gap, which should either be measured or modeled towards some optimizations of the watt balance. A recent publication, i.e. Li et al (2015 Metrologia 52 445), presented a full field mapping method, which in theory will supply useful information for profile characterization and misalignment analysis. This article is an additional material of Li et al (2015 Metrologia 52 445), which develops a different analytical algorithm to represent the 3D magnetic field of a watt balance magnet based on only one measurement for the radial magnetic flux density along the vertical direction, B r (z). The new algorithm is based on the electromagnetic nature of the magnet, which has a much better accuracy.

  8. Simulated water balance of Scots pine stands in Sweden for different climate change scenarios

    NASA Astrophysics Data System (ADS)

    Gärdenäs, Annemieke I.; Jansson, Per-Erik

    1995-03-01

    The effects of climate change on the water balance of Scots pine were studied with a coupled water and heat flow model called 'SOIL'. Two forest soil types (a silty-sand and a sand) at five locations in Sweden were chosen to represent sites with different air temperature, growing season length and precipitation excess. The simulated water balance for the period 1961-1987 was compared with those simulated with two climate change scenario schemes: one is based on increased temperature and the other on both increased temperature and increased precipitation. Different assumptions regarding the effects of changes in leaf area index and minimum canopy resistance on transpiration were studied. Water stress increased substantially in the scenarios based on increased temperature only, which prevented transpiration from increasing. But with scenarios based on simultaneous changes in temperature and precipitation, water stress increased mainly during spring and transpiration increased by 50 mm and 100 mm in northern and southern Sweden, respectively, i.e. by 30-50%. When simultaneous changes in climate and stand characteristics were assumed, transpiration increased by 30-70% with the relative change being greatest for northern Sweden. Differences in water balance between the locations and soil types were less pronounced in the climate change scenarios than in the present climate scenario.

  9. Shift of annual water balance in the Budyko space for a catchment with groundwater dependent evapotranspiration

    NASA Astrophysics Data System (ADS)

    Wang, X.-S.; Zhou, Y.

    2015-11-01

    Empirical equations have been formulated for the general relationship between the evapotranspiration ratio (F) and the aridity index (φ) in the Budyko framework. Though it is normally applied for mean annual behaviors, the Budyko hypothesis has been directly adopted to analyze the interannual change in water balance. However, there are reported cases where the annual evapotranspiration ratio is larger than 1.0 (F > 1). This study reveals the effects of groundwater dependent evapotranspiration in triggering such abnormal shift of annual water balance in the Budyko space. A widely used monthly hydrological model, the ABCD model, is modified to incorporate the groundwater dependent evapotranspiration in the zone with shallow water table and delayed groundwater recharge in the zone with deep water table. This model is applied in the Hailiutu River catchment in China. Results show that the variations in the annual evapotranspiration ratio with aridity index do not satisfy the traditional Budyko hypothesis. The shift of the annual water balance in the Budyko space depends on the proportion of shallow water table area, intensity of groundwater dependent evapotranspiration, and the normal Budyko-type trend of F in the deep groundwater zone. Excess evapotranspiration (F > 1) could occur in extreme dry years, which is enhanced by groundwater-dependent evapotranspiration. Use of groundwater for irrigation may increase the frequency of occurrence of the F > 1 cases.

  10. Balanced Central Schemes for the Shallow Water Equations on Unstructured Grids

    NASA Technical Reports Server (NTRS)

    Bryson, Steve; Levy, Doron

    2004-01-01

    We present a two-dimensional, well-balanced, central-upwind scheme for approximating solutions of the shallow water equations in the presence of a stationary bottom topography on triangular meshes. Our starting point is the recent central scheme of Kurganov and Petrova (KP) for approximating solutions of conservation laws on triangular meshes. In order to extend this scheme from systems of conservation laws to systems of balance laws one has to find an appropriate discretization of the source terms. We first show that for general triangulations there is no discretization of the source terms that corresponds to a well-balanced form of the KP scheme. We then derive a new variant of a central scheme that can be balanced on triangular meshes. We note in passing that it is straightforward to extend the KP scheme to general unstructured conformal meshes. This extension allows us to recover our previous well-balanced scheme on Cartesian grids. We conclude with several simulations, verifying the second-order accuracy of our scheme as well as its well-balanced properties.

  11. Sustainable energy development and water supply security in Kamojang Geothermal Field: The Energy-Water Nexus

    NASA Astrophysics Data System (ADS)

    Sofyan, Y.; Nishijima, J.; Fujimitsu, Y.

    2014-12-01

    The Kamojang Geothermal Field (KGF) is a typical vapor dominated hydrothermal system in West Java, Indonesia. This geothermal field is the oldest exploited geothermal field in Indonesia. From 1983 to 2005, more than 160 million tons of steam have been exploited from the KGF and more than 30 million tons of water were injected into the reservoir system. The injected water come from condensed water, local river and ground water. Sustainable production in the geothermal energy development is the ability of the production system applied to sustain the stable production level over long times and to manage the mass balance between production, injection and natural recharge in the geothermal reservoir during exploitation. Mass balance in the reservoir system can be monitored by using time lapse gravity monitoring. Mass variation of hydrodynamic in the reservoir of KGF from 1999 to 2005 is about -3.34 Mt/year while is about -3.78 Mt/year from 1999 to 2008. Another period between 2009 and 2010, mass variation decreased about -8.24 Mt. According to the history of production and injection, natural recharge to the KGF's reservoir is estimated at about 2.77 Mt/year from 1999 to 2005 and 2.75 Mt/year from 1999 to 2008. Between 2009 and 2010, KGF has a bigger mass deficiency rate throughout 200 MWe maintain production. Large amount of fresh water is needed for sustainable geothermal energy production, while the domestic water supply need is also increased. Natural recharge, about 50% of injected water, cooling system, drilling and other production activities in KGF spend large amounts of fresh water. Water consumption for local people around KGF is about 1.46 MT/year. The water volume around KGF of total runoff is the range between dry season 0.07 MT/month and rainy season 4.4 MT/month. The water demands for sustainable geothermal production of KGF and for local people's consumption will increase in the future. Integrated planning between the energy and water sectors in KGF

  12. Active tower damping and pitch balancing - design, simulation and field test

    NASA Astrophysics Data System (ADS)

    Duckwitz, Daniel; Shan, Martin

    2014-12-01

    The tower is one of the major components in wind turbines with a contribution to the cost of energy of 8 to 12% [1]. In this overview the load situation of the tower will be described in terms of sources of loads, load components and fatigue contribution. Then two load reduction control schemes are described along with simulation and field test results. Pitch Balancing is described as a method to reduce aerodynamic asymmetry and the resulting fatigue loads. Active Tower Damping is reducing the tower oscillations by applying appropiate pitch angle changes. A field test was conducted on an Areva M5000 wind turbine.

  13. What are the key drivers of regional differences in the water balance on the Tibetan Plateau?

    NASA Astrophysics Data System (ADS)

    Biskop, S.; Maussion, F.; Krause, P.; Fink, M.

    2015-04-01

    Lake-level fluctuations in closed basins on the Tibetan Plateau (TP) indicate climate-induced changes in the regional water balance. However, little is known about the region's key hydrological parameters, hampering the interpretation of these changes. The purpose of this study is to contribute to a more quantitative understanding of these controls. Four lakes in the south-central part of the TP were selected to analyze the spatiotemporal variations of water-balance components: Nam Co and Tangra Yumco (indicating increasing water levels), and Mapam Yumco and Paiku Co (indicating stable or slightly decreasing water levels). We present the results of an integrated approach combining hydrological modeling, atmospheric-model output and remote-sensing data. The hydrological model J2000g was adapted and extended according to the specific characteristics of closed lake basins on the TP and driven with "High Asia Refined analysis (HAR)" data at 10 km resolution for the period 2001-2010. Our results reveal that because of the small portion of glacier areas (1 to 7% of the total basin area) the contribution of glacier melt water accounts for only 14-30% of total runoff during the study period. Precipitation is found to be the principal factor controlling the water-balance in the four studied basins. The positive water balance in the Nam Co and Tangra Yumco basins was primarily related to larger precipitation amounts and thus higher runoff rates in comparison with the Paiku Co and Mapam Yumco basins. This study highlights the benefits of combining atmospheric and hydrological modeling. The presented approach can be readily transferred to other ungauged lake basins on the TP, opening new directions of research. Future work should go towards increasing the atmospheric model's spatial resolution and a better assessment of the model-chain uncertainties, especially in this region where observational data is missing.

  14. Consequences of declining snow accumulation for water balance of mid-latitude dry regions

    USGS Publications Warehouse

    Schlaepfer, Daniel R.; Lauenroth, William K.; Bradford, John B.

    2012-01-01

    Widespread documentation of positive winter temperature anomalies, declining snowpack and earlier snow melt in the Northern Hemisphere have raised concerns about the consequences for regional water resources as well as wildfire. A topic that has not been addressed with respect to declining snowpack is effects on ecosystem water balance. Changes in water balance dynamics will be particularly pronounced at low elevations of mid-latitude dry regions because these areas will be the first to be affected by declining snow as a result of rising temperatures. As a model system, we used simulation experiments to investigate big sagebrush ecosystems that dominate a large fraction of the semiarid western United States. Our results suggest that effects on future ecosystem water balance will increase along a climatic gradient from dry, warm and snow-poor to wet, cold and snow-rich. Beyond a threshold within this climatic gradient, predicted consequences for vegetation switched from no change to increasing transpiration. Responses were sensitive to uncertainties in climatic prediction; particularly, a shift of precipitation to the colder season could reduce impacts of a warmer and snow-poorer future, depending on the degree to which ecosystem phenology tracks precipitation changes. Our results suggest that big sagebrush and other similar semiarid ecosystems could decrease in viability or disappear in dry to medium areas and likely increase only in the snow-richest areas, i.e. higher elevations and higher latitudes. Unlike cold locations at high elevations or in the arctic, ecosystems at low elevations respond in a different and complex way to future conditions because of opposing effects of increasing water-limitation and a longer snow-free season. Outcomes of such nonlinear interactions for future ecosystems will likely include changes in plant composition and productivity, dynamics of water balance, and availability of water resources.

  15. Spatially-Explicit Water Balance Implications of Carbon Capture and Sequestration

    NASA Astrophysics Data System (ADS)

    Sathre, R. C.; Breunig, H.; Greenblatt, J.; Larsen, P.; McKone, T.; Quinn, N. W.; Scown, C.

    2012-12-01

    Carbon dioxide capture and sequestration (CCS) is increasingly discussed as a means to reduce greenhouse gas emissions and limit climate destabilization. CCS implementation is likely to have varied effects on local water balances. On one hand, power plants equipped with CO2 capture may require substantially more cooling water than plants without CO2 capture. On the other hand, injection of captured CO2 into saline aquifers may require brine extraction for pressure management, and the extracted brine may be desalinated and used as a fresh water resource. We conduct a geospatial analysis detailing how CCS implementation affects the county-level balance of water supply and demand across the contiguous United States. We calculate baseline water stress indices for each county for the year 2005, and explore CCS deployment scenarios for the year 2030 and their impacts on local water supply and demand. We use GIS mapping to identify locations where water supply will likely not constrain CCS deployment, locations where fresh water supply may constrain CCS deployment but brine extraction can overcome these constraints, and locations where limited fresh water and brine availability are likely to constrain CCS deployment. We conduct sensitivity analyses to determine bounds of uncertainty and to identify the most influential parameters. We find that CCS can strongly affect freshwater supply and demand in specific regions, but overall it has a moderate effect on water balances.; Locations of 217 coal-fired (red) and natural gas-fired (green) power plants that meet criteria for CO2 capture. Size of circle corresponds to amount of CO2 emission in 2005.

  16. Water balance of selected floodplain lake basins in the Middle Bug River valley

    NASA Astrophysics Data System (ADS)

    Dawidek, J.; Ferencz, B.

    2013-08-01

    This study is the first attempt in the literature on the subject of comparing water balance equations for floodplain lake basins depending on the type of connection the lake has to its parent river. Where confluent lakes (upstream connections) were concerned, it was only possible to apply a classic water balance equation. When dealing with contrafluent lakes (downstream connections) as well as lakes with a complex recharge type (contrafluent-confluent) modified equations were created. The hydrological type of a lake is decided by high water flow conditions and, consequently, the duration of potamophase (connection with a river) and limnophase (the isolation of the lake), which determine the values of particular components and the proportion of the vertical to horizontal water exchange rate. Confluent lakes are characterised by the highest proportion of horizontal components (the inflow and runoff of river water) to the vertical ones (precipitation and evaporation). The smallest differences occur with respect to a contrafluent lake. In the case of confluent lakes, the relationship between water balance components resulted from the consequent water flow through the basin, consistent with the slope of the river channel and valley. The supplying channels of contrafluent lakes had an obsequent character, which is why the flow rate was lower. Lakes with a complex, contrafluent-confluent recharge type showed intermediate features. After a period of slow contrafluent recharge, the inflow of water through a downstream crevasse from the area of the headwater of the river was activated; this caused a radical change of flow conditions into confluent ones. The conditions of water retention in lake basins were also varied. Apart from hydrological recharge, also the orographic features of the catchment areas of the lakes played an important role here, for example, the distance from the river channel, the altitude at which a given catchment was located within the floodplain and

  17. Five year water and nitrogen balance for a constructed surface flow wetland treating agricultural drainage waters.

    PubMed

    Borin, Maurizio; Tocchetto, Davide

    2007-07-15

    The performance of a constructed surface flow wetland in reducing diffuse N pollution coming from croplands is being investigated in an ongoing experiment, begun in 1998 in NE Italy. The 0.32 ha wetland is vegetated with Phragmites australis (Cav.) Trin. and Typha latifolia (L.). It receives drainage water from 6 ha of land managed for an experiment on drainage systems, where maize, sugarbeet, winter wheat and soybean are cultivated. During the period 1998-2002, the wetland received from 4698 to 8412 mm of water per year (on average, about 9 times the environmental rainfall); its water regimen was discontinuous and flooding occurred on a variable number of days per year (from 13 to 126). Nitric nitrogen was the most important form of element load. Its concentration in the inflow water over time was rather discontinuous, with median values ranging from 0.2 (in 2001) to 4.5 (in 2000) mg L(-1). Inflow nitric N concentrations were occasionally in the 5-15 mg L(-1) range. Concentrations reduced passing through the wetland, with a more evident effect in the last year. Over 5 years, the wetland received slightly more than 2000 kg ha(-1) of nitrogen, 87% in nitric form mostly from farmland drainage. The remaining 13% of N was applied as organic slurry directly onto the wetland, with 5 distributions during 1998 to assess wetland performance in treating occasional organic loads. Field drainage loads had a discontinuous time pattern and occurred mostly during autumn-winter, with the exception of the 2001-2002 season which was a very dry. The wetland discharged 206 kg ha(-1) of N, over the 5-year period, with an apparent removal efficiency of about 90%. The disappearance was mostly due to plant uptake (1110 kg ha(-1)) and soil accumulation (570 kg ha(-1)), with the contribution of denitrification being estimated at around 7%. PMID:17270250

  18. Can an isotropic plasma pressure distribution be in force balance with the T96 model field?

    NASA Astrophysics Data System (ADS)

    Zaharia, Sorin; Cheng, C. Z.

    2003-11-01

    In this paper we investigate how close the gradient force of an isotropic pressure distribution P can be in force balance with the magnetic (Lorentz) force in the T96 empirical model. The study leads to the conclusion that no isotropic pressure can be found in exact force balance with the magnetic field of the quiet time T96 model. The conclusion is derived from several analyses: (1) computing the loop integral of J × B from the model along a closed contour in the equatorial plane (the integral should vanish if J × B = ∇P); (2) obtaining one-dimensional profiles for P on the Sun-Earth axis by integrating ∇P = J × B and comparing them with observations; and (3) decomposing J × B into gradient-free and curl-free terms (the former term would be zero in an exact equilibrium) and subsequently computing the two terms by solving a Poisson-like equation with constraints. Possible physical reasons for our finding that no P exists such that J × B = ∇P include small mass flows as well as nonisotropic (and possibly even nongyrotropic) terms in the magnetospheric pressure tensor. While the lack of exact force balance with isotropic P will probably be not too serious for many situations, for some physical applications, such as the computation of Birkeland currents using the Vasyliunas relation, care must be exercised if one uses the model field in conjunction with isotropic pressure. Finally, we discuss possible ways of computing magnetospheric configurations in exact force balance with isotropic P by using empirical model fields as a starting point.

  19. Development of a multicomponent force and moment balance for water tunnel applications, volume 1

    NASA Technical Reports Server (NTRS)

    Suarez, Carlos J.; Malcolm, Gerald N.; Kramer, Brian R.; Smith, Brooke C.; Ayers, Bert F.

    1994-01-01

    The principal objective of this research effort was to develop a multicomponent strain gauge balance to measure forces and moments on models tested in flow visualization water tunnels. An internal balance was designed that allows measuring normal and side forces, and pitching, yawing and rolling moments (no axial force). The five-components to applied loads, low interactions between the sections and no hysteresis. Static experiments (which are discussed in this Volume) were conducted in the Eidetics water tunnel with delta wings and a model of the F/A-18. Experiments with the F/A-18 model included a thorough baseline study and investigations of the effect of control surface deflections and of several Forebody Vortex Control (FVC) techniques. Results were compared to wind tunnel data and, in general, the agreement is very satisfactory. The results of the static tests provide confidence that loads can be measured accurately in the water tunnel with a relatively simple multicomponent internal balance. Dynamic experiments were also performed using the balance, and the results are discussed in detail in Volume 2 of this report.

  20. Estimates of the climatological land surface energy- and water balance derived from thermodynamic constraints

    NASA Astrophysics Data System (ADS)

    Kleidon, Axel; Renner, Maik; Porada, Philipp

    2015-04-01

    The land surface energy and water balances are tightly coupled by the partitioning of absorbed solar radiation into terrestrial radiation and the turbulent fluxes of sensible and latent heat, as well as the partitioning of precipitation into evaporation and runoff. Evaporation forms the critical link between these two balances. Its rate is strongly affected by turbulent exchange as it provides the means to efficiently exchange moisture between the heated, moist surface and the cooled, dry atmosphere. Here, we use the constraint that this mass exchange operates at the thermodynamic limit of maximum power to derive analytical expressions for the partitioning of the surface energy and water balances on land. We use satellite-derived forcing of absorbed solar radiation, surface temperature and precipitation to derive simple spatial estimates for the annual mean fluxes of sensible and latent heat and evaluate these estimates with the ERA-Interim reanalysis data set and observations of the discharge of large river basins. Given the extremely simple approach, we find that our estimates explain the climatic mean variations in net radiation, evaporation, and river discharge reasonably well. We conclude that our analytical, minimum approach provides adequate first order estimates of the surface energy and water balance on land and that the thermodynamic limit of maximum power provides a useful closure assumption to constrain the energy partitioning at the land surface.

  1. Development of a multicomponent force and moment balance for water tunnel applications, volume 1

    NASA Astrophysics Data System (ADS)

    Suarez, Carlos J.; Malcolm, Gerald N.; Kramer, Brian R.; Smith, Brooke C.; Ayers, Bert F.

    1994-12-01

    The principal objective of this research effort was to develop a multicomponent strain gauge balance to measure forces and moments on models tested in flow visualization water tunnels. An internal balance was designed that allows measuring normal and side forces, and pitching, yawing and rolling moments (no axial force). The five-components to applied loads, low interactions between the sections and no hysteresis. Static experiments (which are discussed in this Volume) were conducted in the Eidetics water tunnel with delta wings and a model of the F/A-18. Experiments with the F/A-18 model included a thorough baseline study and investigations of the effect of control surface deflections and of several Forebody Vortex Control (FVC) techniques. Results were compared to wind tunnel data and, in general, the agreement is very satisfactory. The results of the static tests provide confidence that loads can be measured accurately in the water tunnel with a relatively simple multicomponent internal balance. Dynamic experiments were also performed using the balance, and the results are discussed in detail in Volume 2 of this report.

  2. Atmospheric water balance and trend over ocean estimated from satellite, merged and reanalysis data

    NASA Astrophysics Data System (ADS)

    Shin, D. B.; Park, H. J.

    2014-12-01

    The column integrated atmospheric water balance over the ocean was examined using satellite-based and merged datasets for the period from 2000 to 2007. The datasets for the components of the atmospheric water balance include evaporation from the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data (HOAPS), the Japanese Ocean Flux Data sets with Use of Remote Sensing Observations (J-OFURO2) and the Objectively Analyzed Air-Sea Heat Fluxes (OAFlux) and precipitation from the HOAPS, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the Global Precipitation Climatology Project (GPCP). The water vapor tendency was derived from water vapor data of HOAPS. The product for water vapor flux convergence estimated using satellite observation data was used. The atmospheric balance components from the Modern-Era Retrospective analysis for Research and Applications (MERRA) reanalysis data were also examined. Residuals of the atmospheric water balance equation were estimated using nine possible combinations of the datasets over the ocean between 60°N and 60°S. The results showed that there was considerable disagreement in the residual intensities and distributions from the different combinations of the datasets. In particular, the residuals in the estimations of the satellite-based atmospheric budget appear to be large over the oceanic areas with heavy precipitation such as the intertropical convergence zone, South Pacific convergence zone, and monsoon regions. The lack of closure of the atmospheric water cycle may be attributed to the uncertainties in the datasets and approximations in the atmospheric water balance equation. Meanwhile, the anomalies of the residuals from the nine combinations of the datasets are in good agreement with their variability patterns. These results suggest that significant consideration is needed when applying the datasets of water budget components to quantitative water budget studies, while climate

  3. The uncertainty of assessments of the water balance components of river basins due to the climate noise

    NASA Astrophysics Data System (ADS)

    Gusev, Yeugeniy; Semenov, Vladimir; Nasonova, Olga; Kovalev, Evgeny

    2016-04-01

    Assessments of hydrological consequences resulted from climate change impact performed by different authors are characterized by a large scatter or uncertainty caused by a number of reasons. Some reasons are subjective, while others are objective. In the present work, the objective uncertainty, which cannot be reduced by means of better physical description of the processes under study or by means of improvement of the quality of input data for atmospheric and hydrological models, and which is an internal feature of the atmosphere - hydrosphere - land surface system, is considered. This uncertainty is caused by a chaotic character of atmospheric processes (i.e. by so-called climatic noise), their instability with respect to small errors in determination of initial conditions for modeling the evolution of meteorological variables. Here, the impact of climatic noise on the uncertainty of hydrological variables (river runoff and evapotranspiration) is studied for two northern river basins located in the Russian Federation: the Lena and Indigirka basins. Such a selection was motivated by the fact, that northern high-latitude land areas are the major source of fresh water resources of our planet, at the same time these areas will be subjected to the earliest and most significant changes, caused by anthropogenic greenhouse gas emissions. The methodology of solving the problem is based on application of the global climate model (GCM) ECHAM5 and the land surface model (LSM) SWAP that allows an estimation of monthly and annual uncertainties in the simulated water balance components (precipitation, river runoff and evapotranspiration) of the selected river basins, resulted from the climatic noise. The ensemble simulations (45 versions) of meteorological fields were performed by ECHAM5. Since meteorological fields modelled by any GCM differ from observations, the post-processing bias-correction was carried out. Then for each river basin and computational experiment

  4. Effects of subfornical organ extracts on salt-water balance in the rat

    NASA Technical Reports Server (NTRS)

    Summy-Long, J. Y.; Crawford, I. L.; Severs, W. B.

    1976-01-01

    The subfornical organ (SFO) is a circumventricular structure located at the junction of the lamina terminalis and the tela choroidea of the third cerebral ventricle. SFO is histologically regarded as a neurosecretory structure, although the physiological effects or biochemical nature of such secretions are not yet ascertained. Results are presented for an experimental study designed to determine whether SFO extracts alter parameters associated with salt-water balance in the rat. The data obtained support the conclusion that SFO contains some water-soluble substance(s), easily released by incubation, dialyzable and heat stable, which influences the salt-water balance after injection into ventricular cerebrospinal fluid. Whether other brain tissues or plasma contains the same or similar material is not yet convincingly established. The observation that one or more active constituents are easily released from SFO upon incubation in potassium-enriched medium may be of value.

  5. Effects of urbanisation on the water balance - A long-term trajectory

    SciTech Connect

    Haase, Dagmar

    2009-07-15

    The amount of land consumption required for housing and transport severely conflicts with both the necessity and the legal obligation to maintain the ecological potential afforded by open spaces to meet the needs of current and future generations with regards to the protection of resources and climate change. Owing to an increasing intensity of soil use, soil conditions appear to have deteriorated in most city regions around the world, namely their filter and runoff regulating functions are impaired by land surfacing. As such soil functions depend on the soil's biophysical properties and the degree of imperviousness, the impact on the water balance caused by urban growth varies considerably. In response to the demand for sustainably secure urban water resources, it needs to be assessed exactly how land surfacing affects the functions concerned. Analysing and evaluating urban land use change on the long-term water balance should improve our understanding of the impact of urbanisation on the water household. Therefore, this paper analyses the impact of urban land use change and land surfacing on the long-term urban water balance over a 130-year trajectory by using simple model approaches that are based on data available to the public. The test site is the city of Leipzig. In particular, attention is to be paid to estimating changes of evapotranspiration, direct runoff and groundwater recharge.

  6. Trip Report-Produced-Water Field Testing

    SciTech Connect

    Sullivan, Enid J.

    2012-05-25

    Los Alamos National Laboratory (LANL) conducted field testing of a produced-water pretreatment apparatus with assistance from faculty at the Texas A&M University (TAMU) protein separation sciences laboratory located on the TAMU main campus. The following report details all of the logistics surrounding the testing. The purpose of the test was to use a new, commercially-available filter media housing containing modified zeolite (surfactant-modified zeolite or SMZ) porous medium for use in pretreatment of oil and gas produced water (PW) and frac-flowback waters. The SMZ was tested previously in October, 2010 in a lab-constructed configuration ('old multicolumn system'), and performed well for removal of benzene, toluene, ethylbenzene, and xylenes (BTEX) from PW. However, a less-expensive, modular configuration is needed for field use. A modular system will allow the field operator to add or subtract SMZ filters as needed to accommodate site specific conditions, and to swap out used filters easily in a multi-unit system. This test demonstrated the use of a commercial filter housing with a simple flow modification and packed with SMZ for removing BTEX from a PW source in College Station, Texas. The system will be tested in June 2012 at a field site in Pennsylvania for treating frac-flowback waters. The goals of this test are: (1) to determine sorption efficiency of BTEX in the new configuration; and (2) to observe the range of flow rates, backpressures, and total volume treated at a given flow rate.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  8. Evaluation of different field methods for measuring soil water infiltration

    NASA Astrophysics Data System (ADS)

    Pla-Sentís, Ildefonso; Fonseca, Francisco

    2010-05-01

    Soil infiltrability, together with rainfall characteristics, is the most important hydrological parameter for the evaluation and diagnosis of the soil water balance and soil moisture regime. Those balances and regimes are the main regulating factors of the on site water supply to plants and other soil organisms and of other important processes like runoff, surface and mass erosion, drainage, etc, affecting sedimentation, flooding, soil and water pollution, water supply for different purposes (population, agriculture, industries, hydroelectricity), etc. Therefore the direct measurement of water infiltration rates or its indirect deduction from other soil characteristics or properties has become indispensable for the evaluation and modelling of the previously mentioned processes. Indirect deductions from other soil characteristics measured under laboratory conditions in the same soils, or in other soils, through the so called "pedo-transfer" functions, have demonstrated to be of limited value in most of the cases. Direct "in situ" field evaluations have to be preferred in any case. In this contribution we present the results of past experiences in the measurement of soil water infiltration rates in many different soils and land conditions, and their use for deducing soil water balances under variable climates. There are also presented and discussed recent results obtained in comparing different methods, using double and single ring infiltrometers, rainfall simulators, and disc permeameters, of different sizes, in soils with very contrasting surface and profile characteristics and conditions, including stony soils and very sloping lands. It is concluded that there are not methods universally applicable to any soil and land condition, and that in many cases the results are significantly influenced by the way we use a particular method or instrument, and by the alterations in the soil conditions by the land management, but also due to the manipulation of the surface

  9. Impact of electromagnetic fields on human vestibular system and standing balance: pilot results and future developments

    NASA Astrophysics Data System (ADS)

    Allen, A.; Villard, S.; Corbacio, M.; Goulet, D.; Plante, M.; Souques, M.; Deschamps, F.; Ostiguy, G.; Lambrozo, J.; Thomas, A. W.; Legros, A.

    2016-03-01

    Although studies have found that extremely low-frequency (ELF, < 300 Hz) magnetic fields (MF) can modulate human standing balance, the acute effects of electromagnetic fields on standing balance have not been systematically investigated. This work aims to establish the threshold for acute standing balance modulation during ELFMF exposure. One hundred volunteers will be exposed to transcranial electric stimulations (Direct Current - DC and Alternating Current - AC, 1 mA) and ELFMF (0 to 160 Hz, 0 to 100 mT). The displacement of their center of pressure will be collected and analyzed as an indicator of vestibular performance. During pilot testing (n=6), we found increased lateral sway with DC, and to a lesser extent, AC exposure. The ELFMF exposure system still needs to be adapted to allow meaningful results. Future protocol design will test for possible effects due to exposures in the radiofrequency range (i.e. above 3 kHz). These results will contribute to the literature documenting exposure guidelines aiming to protect workers and the general public.

  10. Variations of global and continental water balance components as impacted by climate forcing uncertainty and human water use

    NASA Astrophysics Data System (ADS)

    Müller Schmied, Hannes; Adam, Linda; Eisner, Stephanie; Fink, Gabriel; Flörke, Martina; Kim, Hyungjun; Oki, Taikan; Portmann, Felix Theodor; Reinecke, Robert; Riedel, Claudia; Song, Qi; Zhang, Jing; Döll, Petra

    2016-07-01

    When assessing global water resources with hydrological models, it is essential to know about methodological uncertainties. The values of simulated water balance components may vary due to different spatial and temporal aggregations, reference periods, and applied climate forcings, as well as due to the consideration of human water use, or the lack thereof. We analyzed these variations over the period 1901-2010 by forcing the global hydrological model WaterGAP 2.2 (ISIMIP2a) with five state-of-the-art climate data sets, including a homogenized version of the concatenated WFD/WFDEI data set. Absolute values and temporal variations of global water balance components are strongly affected by the uncertainty in the climate forcing, and no temporal trends of the global water balance components are detected for the four homogeneous climate forcings considered (except for human water abstractions). The calibration of WaterGAP against observed long-term average river discharge Q significantly reduces the impact of climate forcing uncertainty on estimated Q and renewable water resources. For the homogeneous forcings, Q of the calibrated and non-calibrated regions of the globe varies by 1.6 and 18.5 %, respectively, for 1971-2000. On the continental scale, most differences for long-term average precipitation P and Q estimates occur in Africa and, due to snow undercatch of rain gauges, also in the data-rich continents Europe and North America. Variations of Q at the grid-cell scale are large, except in a few grid cells upstream and downstream of calibration stations, with an average variation of 37 and 74 % among the four homogeneous forcings in calibrated and non-calibrated regions, respectively. Considering only the forcings GSWP3 and WFDEI_hom, i.e., excluding the forcing without undercatch correction (PGFv2.1) and the one with a much lower shortwave downward radiation SWD than the others (WFD), Q variations are reduced to 16 and 31 % in calibrated and non

  11. Coupled Sensing of Hunger and Thirst Signals Balances Sugar and Water Consumption.

    PubMed

    Jourjine, Nicholas; Mullaney, Brendan C; Mann, Kevin; Scott, Kristin

    2016-08-11

    Hunger and thirst are ancient homeostatic drives for food and water consumption. Although molecular and neural mechanisms underlying these drives are currently being uncovered, less is known about how hunger and thirst interact. Here, we use molecular genetic, behavioral, and anatomical studies in Drosophila to identify four neurons that modulate food and water consumption. Activation of these neurons promotes sugar consumption and restricts water consumption, whereas inactivation promotes water consumption and restricts sugar consumption. By calcium imaging studies, we show that these neurons are directly regulated by a hormone signal of nutrient levels and by osmolality. Finally, we identify a hormone receptor and an osmolality-sensitive ion channel that underlie this regulation. Thus, a small population of neurons senses internal signals of nutrient and water availability to balance sugar and water consumption. Our results suggest an elegant mechanism by which interoceptive neurons oppositely regulate homeostatic drives to eat and drink. PMID:27477513

  12. Water Temperature, Voluntary Drinking and Fluid Balance in Dehydrated Taekwondo Athletes

    PubMed Central

    Khamnei, Saeed; Hosseinlou, Abdollah; Zamanlu, Masumeh

    2011-01-01

    Voluntary drinking is one of the major determiners of rehydration, especially as regards exercise or workout in the heat. The present study undertakes to search for the effect of voluntary intake of water with different temperatures on fluid balance in Taekwondo athletes. Six young healthy male Taekwondo athletes were dehydrated by moderate exercise in a chamber with ambient temperature at 38-40°C and relative humidity between 20-30%. On four separate days they were allowed to drink ad libitum plane water with the four temperatures of 5, 16, 26, and 58°C, after dehydration. The volume of voluntary drinking and weight change was measured; then the primary percentage of dehydration, sweat loss, fluid deficit and involuntary dehydration were calculated. Voluntary drinking of water proved to be statistically different in the presented temperatures. Water at 16°C involved the greatest intake, while fluid deficit and involuntary dehydration were the lowest. Intake of water in the 5°C trial significantly correlated with the subject’s plasma osmolality change after dehydration, yet it showed no significant correlation with weight loss. In conclusion, by way of achieving more voluntary intake of water and better fluid state, recommending cool water (~16°C) for athletes is in order. Unlike the publicly held view, drinking cold water (~5°C) does not improve voluntary drinking and hydration status. Key points For athletes dehydrated in hot environments, maximum voluntary drinking and best hydration state occurs with 16°C water. Provision of fluid needs and thermal needs could be balanced using 16°C water. Drinking 16°C water (nearly the temperature of cool tap water) could be recommended for exercise in the heat. PMID:24149564

  13. River Basin Water Assessment and Balance in fast developing areas in Viet Nam

    NASA Astrophysics Data System (ADS)

    Le, Van Chin; Ranzi, Roberto

    2010-05-01

    Uneven precipitation in space and time together with mismanagement and lack of knowledge about quantity and quality of water resources, have caused water shortages for water supply to large cities and irrigation areas in many regions of Viet Nam in the dry season. The rainy season (from June to October) counts for 80% of the total annual rainfall, while the water volume of dry season (from November to May of the following year) accounts for 20% only. Lack of sufficient water volumes occurs in some areas where the pressure of a fast increasing population (1.3% per year on average in the last decade in Viet Nam), intensive agricultural and industrial uses is one of the major problems facing sustainable development. For those areas an accurate water assessment and balance at the riverbasin scale is needed to manage the exploitation and appropriate use of water resources and plan future development. The paper describes the preliminary phase of the pilot development of the river basin water balance for the Day River Basin in the Red River delta in Viet Nam. The Day river basin includes a 7,897 km² area in the south-western part of the Red River in Viet Nam. The total population in the Day river basin exceeds 8 millions inhabitants, including the Hanoi capital, Nam Dinh and other large towns. Agricultural land covered 390,294 ha in 2000 and this area is going to be increased by 14,000 ha in 2010 due to land reclamation and expansion toward the sea. Agricultural uses exploit about 90% of surface water resources in the Day river basin but have to compete with industrial and civil needs in the recent years. At the background of the brief characterization of the Day River Basin, we concentrate on the application of a water balance model integrated by an assessment of water quality after consumptive uses for civil, agricultural and industrial needs to assist water management in the basin. In addition, future development scenarios are taken into account, considering less

  14. Investigating groundwater-lake interactions by hydraulic heads and a water balance.

    PubMed

    Rudnick, Sebastian; Lewandowski, Jörg; Nützmann, Gunnar

    2015-01-01

    Discharge of groundwater into lakes (lacustrine groundwater discharge, LGD) can play a major role in water balances of lakes. Unfortunately, studies often neglect this input path because of methodological difficulties in its determination. Direct measurements of LGD are labor-consuming and prone to error. The present study uses both spatially variable hydraulic-head data and meteorological data to estimate groundwater input by LGD and lake water output through infiltration. The study sites are two shallow, groundwater-fed lakes without any surface inflows or outflows. Horizontally interpolated groundwater heads were combined with lake water levels to obtain vertical hydraulic gradients between the aquifer and the lake, which are separated by a thick layer of lake bed sediment which has a much lower hydraulic conductivity than the underlying aquifer. By fitting the hydraulic gradient to the results of a simple mass balance and considering the process of clogging, we were able to estimate the hydraulic conductivity of the lake bed sediments. We calculated groundwater inputs by LGD and lake water outputs by infiltration on an annual basis. Although our method requires several assumptions, the results are reasonable and provide useful information about the exchange between the aquifer and the lake, which can, for example, be used for the calculation of nutrient mass balances. PMID:24854019

  15. The influence of frozen soil change on water balance in the upper Yellow River Basin, China

    NASA Astrophysics Data System (ADS)

    Cuo, L.; Zhao, L.; Zhou, B.

    2013-12-01

    Yellow River supports 30% of China's population and 13% of China's total cultivated area. About 35% of the Yellow River discharge comes from the upper Yellow River Basin. Seasonally frozen, continuous and isolated permafrost soils coexist and cover the entire upper Yellow River Basin. The spatial distribution of various frozen soisl is primarily determined by the elevation in the basin. Since the past five decades, air temperature has increased by a rate of 0.03 C/year in the upper Yellow River Basin. Many studies reported the conversions of continuous to isolated permafrost soil, permafrost soil to seasonally frozen soil and the thickening of the active layer due to rising temperature in the basin. However, very few studies reported the impact of the change of frozen soil on the water balance in the basin. In this study, the Variable Infiltration Capacity (VIC) model is applied in the upper Yellow River Basin to study the change of frozen soil and its impact on the water balance. Soil temperature and soil liquid content measured up to 3 m below ground surface at a number of sites in the upper Yellow River Basin and the surroundings are used to evaluate the model simulation. Streamflow is also calibrated and validated using historical streamflow records. The validated VIC model is then used to investigate the frozen soil change and the impact of the change on water balance terms including surface runoff, baseflow, evapotranspiration, soil water content, and streamflow in the basin.

  16. A water balance approach for reconstructing streamflow using tree-ring proxy records

    NASA Astrophysics Data System (ADS)

    Saito, Laurel; Biondi, Franco; Devkota, Rajan; Vittori, Jasmine; Salas, Jose D.

    2015-10-01

    Tree-ring data have been used to augment limited instrumental records of climate and provide a longer view of past variability, thus improving assessments of future scenarios. For streamflow reconstructions, traditional regression-based approaches cannot examine factors that may alter streamflow independently of climate, such as changes in land use or land cover. In this study, seasonal water balance models were used as a mechanistic approach to reconstruct streamflow with proxy inputs of precipitation and air temperature. We examined a Thornthwaite water balance model modified to have seasonal components and a simple water balance model with a snow component. These two models were calibrated with a shuffled complex evolution approach using PRISM and proxy seasonal temperature and precipitation to reconstruct streamflow for the upper reaches of the West Walker River basin at Coleville, CA. Overall, the modified Thornthwaite model performed best during calibration, with R2 values of 0.96 and 0.80 using PRISM and proxy inputs, respectively. The modified Thornthwaite model was then used to reconstruct streamflow during AD 1500-1980 for the West Walker River basin. The reconstruction included similar wet and dry episodes as other regression-based records for the Great Basin, and provided estimates of actual evapotranspiration and of April 1 snow water equivalence. Given its limited input requirements, this approach is suitable in areas where sparse instrumental data are available to improve proxy-based streamflow reconstructions and to explore non-climatic reasons for streamflow variability during the reconstruction period.

  17. Links Between Flood Frequency and Annual Water Balance Behaviors: A Basis for Similarity and Regionalization

    SciTech Connect

    Guo, Jiali; Li, Hongyi; Leung, Lai-Yung R.; Guo, Shenglian; Liu, Pan; Sivapalan, Murugesu

    2014-03-28

    This paper presents the results of a data based comparative study of several hundred catchments across continental United States belonging to the MOPEX dataset, which systematically explored the connection between the flood frequency curve and measures of mean annual water balance. Two different measures of mean annual water balance are used: (i) a climatic aridity index, AI, which is a measure of the competition between water and energy availability at the annual scale; and, (ii) baseflow index, BFI, the ratio of slow runoff to total runoff also at the annual time scale, reflecting the role of geology, soils, topography and vegetation. The data analyses showed that the aridity index, AI, has a first order control on both the mean and Cv of annual maximum floods. While mean annual flood decreases with increasing aridity, Cv increases with increasing aridity. BFI appeared to be a second order control on the magnitude and shape of the flood frequency curve. Higher BFI, meaning more subsurface flow and less surface flow leads to a decrease of mean annual flood whereas lower BFI leads to accumulation of soil moisture and increased flood magnitudes that arise from many events acting together. The results presented in this paper provide innovative means to delineate homogeneous regions within which the flood frequency curves can be assumed to be functionally similar. At another level, understanding the connection between annual water balance and flood frequency will be another building block towards developing comprehensive understanding of catchment runoff behavior in a holistic way.

  18. Water balance in the Poznan region (Poland) - the present and the future

    NASA Astrophysics Data System (ADS)

    Szwed, M.

    2009-04-01

    In the present climate the Wielkopolska region (e.g. the Poznań area) suffers water shortages. Unfortunately, climate projections for the future foresee further worsening of the water condition caused by higher temperatures occurring simultaneously with changes in distribution and quantity of precipitations simultaneously. In this study the water balance components, i.e. precipitation, evaporation and runoff in the Poznań region will be examined for the average conditions in the present (1961-1990) and in the future (2071-2100). All calculations will be studied based on the results of daily temperature, precipitation, relative humidity and wind speed for several regional climate models in the periods of 1961-1990 and 2071-2100. The values of evaporation for the different land use units will be estimated based on the method developed in the Department of Agrometeorology of the Poznań University of Life Sciences. This method was developed for the purpose of estimating heat balance components based on standard meteorological data, plant development stage, and land-use conditions. Estimates of latent heat flux components allowed to obtain values of areal evapotranspiration and surface runoff. The values of the water balance components obtained based on different models will be discussed and compared with each other. The water balance components in the region for the present and for the future will be compared as well. The directions of changes in the studied components will be recognized and discussed. Based on the estimations for the future, the likely changes in the land use in the regions caused by the changing climate conditions in the region, if any, will be presented.

  19. Water and Energy Balance in Response to the Removal of Invasive Phragmites Australis in a Riparian Wetland

    NASA Astrophysics Data System (ADS)

    Mykleby, P.; Lenters, J. D.; Cutrell, G. J.; Herrman, K.; Istanbulluoglu, E.; Scott, D.

    2011-12-01

    Vegetation plays an important role in the surface energy and water balance of wetlands. Transpiration from phreatophytes, in particular, withdraws water directly from groundwater, often impacting streamflow rates in adjacent tributaries. In the Republican River basin of the Central Plains (USA), streamflow has declined significantly in the past 30-40 years. Invasive vegetation species (such as Phragmites australis) have been removed from portions of the riparian corridor in an effort to halt or reverse the downward trend in streamflow. In this study, we investigated the energy and water balance of a P. australis-dominated riparian wetland in south-central Nebraska to assess the potential effectiveness of such an approach. Evapotranspiration (ET) rates were measured during two growing seasons - one being 2009, when the P. australis was at full growth, and the other during 2010, after the vegetation had been sprayed with herbicide (and remained only as dead, standing biomass). Energy balance measurements at the field site included net radiation, heat storage rates in the canopy, soil, and standing water, and sensible heat flux, which was measured using a large-aperture scintillometer (LAS). Latent heat flux (i.e., ET) was calculated as a residual of the energy balance, and comparisons were made between the two growing seasons. As a result of the spraying of the P. australis vegetation, season-mean ET rates dropped from 4.4 mm day-1 in 2009 to 3.0 mm day-1 in 2010. This decrease in ET was associated with a large increase in sensible heat flux, which more than doubled between the two years (from 33 W m-2 in 2009 to 76 W m-2 in 2010). Meteorological conditions at the site were slightly different from one year to the next, but the differences were not large enough to account for the dramatic changes in latent and sensible heat flux that were observed. We conclude, therefore, that the majority of the ~30% decrease in ET (and ~130% increase in sensible heat flux) was the

  20. Optional water development strategies for the Yellow River Basin: Balancing agricultural and ecological water demands

    NASA Astrophysics Data System (ADS)

    Cai, Ximing; Rosegrant, Mark W.

    2004-08-01

    The Yellow River Basin is of the utmost importance for China in terms of food production, natural resources management, and socioeconomic development. Water withdrawals for agriculture, industry, and households in the past decade have seriously depleted environmental and ecological water requirements in the basin. This study presents a modeling scenario analysis of some water development strategies to harmonize water withdrawal demand and ecological water demand in the Yellow River Basin through water savings and interbasin water transfers. A global water and food analysis model including the Yellow River Basin as one of the modeling units is applied for the analysis. The model demonstrates that there is little hope of resolving the conflict between agriculture water demand and ecological water demand in the basin if the current water use practices continue. Trade-offs exist between irrigation water use and ecological water use, and these trade-offs will become more intense in future years with population growth, urbanization, and industrial development as well as growing food demand. Scenario analysis in this study concludes that increasing basin water use efficiency to 0.67 first and then supplementary water availability by interbasin water transfer through the South-North Water Transfer Project may provide a solution to water management of the Yellow River Basin in the next 25 years.

  1. Entropy of Egypt's virtual water trade gravity field

    NASA Astrophysics Data System (ADS)

    Karakatsanis, Georgios; Bierbach, Sandra

    2016-04-01

    The study investigates the entropy of Egypt's virtual water trade gravity distribution, in order to provide a chart of Egypt's embodied water balance in agricultural trade, in relation to distances with its major counterparties. Moreover, our calculations on the amount of the embodied water traded between Egypt and each of its partners take place according to a combination of available data on the blue, green and grey water footprints as well as the Food and Agriculture Organization (FAO) database of traded amounts per crop type. A study on the virtual water trade gravity, enables us to enrich former related studies (Fracasso 2014; Fracasso, Sartori and Schiavo 2014) via examining Egypt's water supply dependence on the Nile River and if comparative advantages -purely from the side of water quantities- can be identified via recognizing which water footprint categories are particularly high. Additionally, this methodology can comprise -from a fundamental level- a guide for revealing the importance of water footprint types for Egypt's agricultural sector; hence, Egypt's potential comparative advantages, as far as quantitative water endowments are exclusively concerned (without consideration of water or crop prices). Although it is pointed out very correctly by various authors (Antonelli and Sartori 2014) that the virtual water trade concept does not incorporate many important aspects of water supply -such as heavy water price subsidizing- to be used accurately for the identification of comparative advantages, we consider that the purely quantitative examination can provide strong fundamental indications -especially for green and grey water footprints, which are hypothesized to be less sensitive to subsidizing. In overall, this effect can very well provide a primary indication on the organization of the global alimentation trade network (Yang et al. 2006). The gravity equation used contains water footprint data for the 15 top traded crops and the distances for Egypt

  2. Effect of water supply method and flow rate on drinking behavior and fluid balance in horses.

    PubMed

    Nyman, S; Dahlborn, K

    2001-05-01

    This study investigated three methods of water supply on drinking preference and behavior in six Standardbred geldings (2-9 years, 505+/-9 kg). The water sources were buckets (B), pressure valve (PV), and float valve (FV) bowls. In an initial drinking preference test, PV was tested at three flow rates: 3, 8, and 16 l/min (PV3, PV8, and PV16), and FV at 3 l/min (FV3). Water intake was measured in l and presented as the percentage of the total daily water intake from each of two simultaneously presented alternatives. The intake from PV8 was greater than from both PV3 (72+/-11% vs. 28+/-11%) and PV16 (90+/-4% vs. 10+/-4%). All horses showed a strong preference for B, 98+/-1% of the intake compared to 2+/-1% from PV8. Individual variation in the data gave no significant difference in preference between the two automatic bowls. In the second part of the study, drinking behavior and fluid balance were investigated when the horses drank from FV3, PV8, and B for 7 consecutive days in a changeover design. Despite a tendency for an increase in total daily drinking time from FV3, the daily water intake was significantly lower (43+/-3 ml/kg) than from PV8 (54+/-2 ml/kg) and B (58+/-3 ml/kg). Daily net water gain [intake-(fecal+urinary output)] was only 0.5+/-3 ml/kg with FV3, resulting in a negative fluid balance if insensible losses are included. These results show that the water supply method can affect both drinking behavior and fluid balance in the horse. PMID:11399288

  3. Hydromorphological analysis and water balance modelling of ombro- and mesotrophic peatlands

    NASA Astrophysics Data System (ADS)

    Edom, F.; Münch, A.; Dittrich, I.; Keßler, K.; Peters, R.

    2010-10-01

    The hydromorphological analysis (HMA) is a method to quantify the potentials of mire revitalisation. In this study, the HMA is combined with the new peatland-tool of the water balance model AKWA-M®. This peatland-tool includes as well depth functions of the hydraulic conductivity and drainable porosity for several mire-ecotope-types as specific equations for mire evapotranspiration. The calculations were applied in several peatlands and mires of the German-Czech Ore Mountains (Erzgebirge/Krušné hory). The simulation results show that the chosen depth functions are valuable for the water balance calculation of mire ecotopes with a fully developed akrotelm like ombro- and mesotrophic peatlands. For degenerated peat soil or regenerating mires it is necessary to improve the model and the parameter calibration, especially the depth functions, with additional measured data in different peatlands.

  4. Nitrogen transformations and balance in constructed wetlands for slightly polluted river water treatment using different macrophytes.

    PubMed

    Wu, Haiming; Zhang, Jian; Wei, Rong; Liang, Shuang; Li, Cong; Xie, Huijun

    2013-01-01

    Nitrogen removal processing in different constructed wetlands treating different kinds of wastewater often varies, and the contribution to nitrogen removal by various pathways remains unclear. In this study, the seasonal nitrogen removal and transformations as well as nitrogen balance in wetland microcosms treating slightly polluted river water was investigated. The results showed that the average total nitrogen removal rates varied in different seasons. According to the mass balance approach, plant uptake removed 8.4-34.3 % of the total nitrogen input, while sediment storage and N(2)O emission contributed 20.5-34.4 % and 0.6-1.9 % of nitrogen removal, respectively. However, the percentage of other nitrogen loss such as N(2) emission due to nitrification and denitrification was estimated to be 2.0-23.5 %. The results indicated that plant uptake and sediment storage were the key factors limiting nitrogen removal besides microbial processes in surface constructed wetland for treating slightly polluted river water. PMID:22707115

  5. The water balance of a first order catchment in the montane grasslands of South Africa

    NASA Astrophysics Data System (ADS)

    Everson, C. S.

    2001-01-01

    Measurements of daily actual evaporation, streamflow, rainfall and soil water storage were measured for a two-year period in a 97 ha grassland catchment located in the Natal Drakensberg. Actual evaporation was measured using the Bowen ratio energy balance technique. Annual precipitation and discharge data were also used to estimate evaporation over a number of years. Results show that in normal years precipitation is equally split between evaporation and streamflow. In dry years evaporation is the dominant component of the water balance. The data were used to develop simple expressions to calculate annual streamflow and evaporation. Good agreements between actual and modelled trends of streamflow using the ACRU hydrological model were found ( r=0.80). In general ACRU underestimated streamflow by 15%.

  6. The Agony of Choice: How Plants Balance Growth and Survival under Water-Limiting Conditions1

    PubMed Central

    Claeys, Hannes; Inzé, Dirk

    2013-01-01

    When confronted with water limitation, plants actively reprogram their metabolism and growth. Recently, it has become clear that growing tissues show specific and highly dynamic responses to drought, which differ from the well-studied responses in mature tissues. Here, we provide an overview of recent advances in understanding shoot growth regulation in water-limiting conditions. Of special interest is the balance between maintained growth and competitiveness on the one hand and ensured survival on the other hand. A number of master regulators controlling this balance have been identified, such as DELLAs and APETALA2/ETHYLENE RESPONSE FACTOR-type transcription factors. The possibilities of engineering or breeding crops that maintain growth in periods of mild drought, while still being able to activate protective tolerance mechanisms, are discussed. PMID:23766368

  7. Modeling landscape evapotranspiration by integrating land surface phenology and a water balance algorithm

    USGS Publications Warehouse

    Senay, Gabriel B.

    2008-01-01

    The main objective of this study is to present an improved modeling technique called Vegetation ET (VegET) that integrates commonly used water balance algorithms with remotely sensed Land Surface Phenology (LSP) parameter to conduct operational vegetation water balance modeling of rainfed systems at the LSP’s spatial scale using readily available global data sets. Evaluation of the VegET model was conducted using Flux Tower data and two-year simulation for the conterminous US. The VegET model is capable of estimating actual evapotranspiration (ETa) of rainfed crops and other vegetation types at the spatial resolution of the LSP on a daily basis, replacing the need to estimate crop- and region-specific crop coefficients.

  8. BALANCE : a computer program for calculating mass transfer for geochemical reactions in ground water

    USGS Publications Warehouse

    Parkhurst, David L.; Plummer, L. Niel; Thorstenson, Donald C.

    1982-01-01

    BALANCE is a Fortran computer designed to define and quantify chemical reactions between ground water and minerals. Using (1) the chemical compositions of two waters along a flow path and (2) a set of mineral phases hypothesized to be the reactive constituents in the system, the program calculates the mass transfer (amounts of the phases entering or leaving the aqueous phase) necessary to account for the observed changes in composition between the two waters. Additional constraints can be included in the problem formulation to account for mixing of two end-member waters, redox reactions, and, in a simplified form, isotopic composition. The computer code and a description of the input necessary to run the program are presented. Three examples typical of ground-water systems are described. (USGS)

  9. Water balance model for polymer electrolyte fuel cells with ultrathin catalyst layers.

    PubMed

    Chan, Karen; Eikerling, Michael

    2014-02-01

    We present a water balance model of membrane electrode assemblies (MEAs) with ultrathin catalyst layers (UTCLs). The model treats the catalyst layers in an interface approximation and the gas diffusion layers as linear transmission lines of water fluxes. It relates current density, pressure distribution, and water fluxes in the different functional layers of the assembly. The optimal mode of operation of UTCLs is in a fully flooded state. The main challenge for MEAs with UTCLs is efficient liquid water removal, to avoid flooding of the gas diffusion layers. The model provides strategies for increasing the critical current density for the onset of flooding, via liquid permeabilities, vaporization areas, and gas pressure differentials. Finally, we discuss methods to identify regimes of transport via water flux measurements. PMID:24343559

  10. Torque-consistent 3D force balance and optimization of non-resonant fields in tokamaks

    NASA Astrophysics Data System (ADS)

    Park, Jong-Kyu

    2015-11-01

    A non-axisymmetric magnetic perturbation in tokamaks breaks the toroidal symmetry and produces toroidal torque, which is well known as neoclassical toroidal viscosity (NTV) effects. Although NTV torque is second order, it is the first-order change in the pressure anisotropy that drives currents associated with local torques and thereby modifies the field penetration in force balance. The force operator becomes non-Hermitian, but can be directly solved using parallel, toroidal, and radial force balance, leading to a modified Euler-Lagrange equation. The general perturbed equilibrium code (GPEC), which has been successfully developed to solve the modified Euler-Lagrange equation, gives the torque-consistent 3D force balance as well as self-consistent NTV torque. The self-shielding of the torque becomes apparent in the solutions in high β, which was implied in recent MARS-K applications. Furthermore, the full response matrix including the torque in GPEC provides a new and systematic way of optimizing torque and non-resonant fields. Recently the optimization of 3D fields for torque has been actively studied using the stellarator optimizing tools, but the efficiency and accuracy can be greatly improved by directly incorporating the torque response matrix. There are salient features uncovered by response with the torque, as the response can become invisible in amplitudes but only significant in toroidal phase shift. A perturbation in backward helicity is an example, in which NTV can be induced substantially but quietly without measurable response in amplitudes. A number of other GPEC applications will also be discussed, including the multi-mode responses in high- β tokamak plasmas and the new non-axisymmetric control coil (NCC) design in NSTX-U. This work was supported by DOE Contract DE-AC02-09CH11466.

  11. Relation between Water Balance and Climatic Variables Associated with the Geographical Distribution of Anurans

    PubMed Central

    Titon, Braz; Gomes, Fernando Ribeiro

    2015-01-01

    Amphibian species richness increases toward the equator, particularly in humid tropical forests. This relation between amphibian species richness and environmental water availability has been proposed to be a consequence of their high rates of evaporative water loss. In this way, traits that estimate water balance are expected to covary with climate and constrain a species’ geographic distribution. Furthermore, we predicted that coexisting species of anurans would have traits that are adapted to local hydric conditions. We compared the traits that describe water balance in 17 species of anurans that occur in the mesic Atlantic Forest and xeric Cerrado (savannah) habitats of Brazil. We predicted that species found in the warmer and dryer areas would show a lower sensitivity of locomotor performance to dehydration (SLPD), increased resistance to evaporative water loss (REWL) and higher rates of water uptake (RWU) than species restricted to the more mesic areas. We estimated the allometric relations between the hydric traits and body mass using phylogenetic generalized least squares. These regressions showed that REWL scaled negatively with body mass, whereas RWU scaled positively with body mass. Additionally, species inhabiting areas characterized by higher and more seasonally uniform temperatures, and lower and more seasonally concentrated precipitation, such as the Cerrado, had higher RWU and SLPD than species with geographical distributions more restricted to mesic environments, such as the Atlantic Forest. These results support the hypothesis that the interspecific variation of physiological traits shows an adaptation pattern to abiotic environmental traits. PMID:26469787

  12. Logs and completion data for water and mass balance wells in Mortandad and Ten Site Canyons

    SciTech Connect

    McLin, S.G.; Purtymun, W.D.; Swanton, A.S.; Koch, R.J.

    1997-10-01

    Twenty-four monitoring wells were drilled and completed in December 1994 as part of a water and mass balance study for the shallow perched aquifer in the Mortandad Canyon alluvium and in the lower part of Ten-Site Canyon. The wells penetrated the alluvium containing the aquifer and were completed into the top of the weathered tuff. Twelve of these wells encountered the Tshirege Member (Cooing Unit 1 g) of the Bandelier Tuff below the canyon alluvium, while ten wells made contact with the Cerro Toledo interval, which lies between the Tshirege and Otowi Members of the Bandelier Tuff. The remaining two wells were completed into the alluvium above the weathered tuff contact. These wells provide access for continuous water level measurement and water sampling. Data from these new wells will be used to determine changes in alluvial aquifer water storage, water quality sampling, and estimation of seepage into the unsaturated Bandelier Tuff below the alluvium. This report documents drilling activities and well completion logs for the water and mass balance study. These wells also provide critical new data for fourteen north-south vertical cross-sections constructed for the canyon alluvium.

  13. Using Water Isotope Tracers to Investigate Past and Present Water Balance Conditions in the Old Crow Flats, Yukon Territory

    NASA Astrophysics Data System (ADS)

    Turner, K.; Wolfe, B. B.; Edwards, T. W.

    2010-12-01

    The Old Crow Flats (OCF), Yukon Territory, is a wetland of international significance that comprises approximately 2700 shallow thermokarst lakes. Located near the northern limit of the boreal forest, the OCF provides vital habitat for abundant wildlife including waterfowl, moose, muskrat, and the Porcupine Caribou Herd, which support the traditional lifestyle of the Vuntut Gwitchin First Nation. Thermokarst lakes, which occupy vast northern regions, are greatly influenced by climate conditions. In the OCF and other regions there have been observations of decreasing water levels and an increase in frequency of lake drainage events over recent decades. Though there is widespread concern that thermokarst landscape changes are accelerating as a result of ongoing climate change, there are few studies that have investigated current and past variability of lake water balances and climate interactions at the landscape scale. As part of a Government of Canada International Polar Year multidisciplinary project, the present and past hydrology of lakes spanning the OCF are being investigated using water isotope tracers and paleolimnological approaches. Water samples were obtained from 57 lakes three times over three ice-free seasons (2007-09) and analyzed for oxygen and hydrogen isotope composition in order to capture seasonal and interannual changes in water balance conditions. Results highlight strong diversity in the hydrology of lakes throughout the OCF. Based on patterns of isotopic evolution and calculations of input source compositions and evaporation-to-inflow ratios, we identified snowmelt-dominated, rainfall-dominated, groundwater-influenced, evaporation-dominated and drained lake types, which represent the dominant hydrological processes influencing lake water balances. Lake physical and catchment land cover characteristics influence dominant input type (rain or snow). Snowmelt-dominated catchments are large relative to lake surface areas and typically contain

  14. Produced water treating equipment: Recent field tests

    SciTech Connect

    Matthews, R.R.; Choi, M.S.

    1987-01-01

    For several decades, flotation cells have been workhorses for treatment of oilfield produced water for disposal or reinjection. In the last few years several alternative devices which have come on the market for the removal of oil from water have been tested in the oil field. Some of these have distinct advantages over flotation cells in terms of space and weight, better oil-recovery efficiency, and lower operating costs. This paper summarizes the results of field trials of a passive hydrocyclone, in the Arabian Gulf and in the North Sea, a coalescer which uses a specially treated ion-exchange resin as a medium in the Gulf of Mexico, two somewhat similar filter-coalescers which use crushed nut shells as media, onshore in New Mexico, West Texas, and California, and an upflow sand coalescer system in New Mexico and West Texas.

  15. Influence of the hydrophilic-lipophilic balance of sunscreen emulsions on their water resistance property.

    PubMed

    Couteau, Céline; Demé, Alexandre; Cheignon, Clotilde; Coiffard, Laurence J M

    2012-11-01

    The use of sunscreens with sun protective cloths is the photoprotection way mostly used by Occidentals. During sweating or a bath, those products should be still efficient. As the emulsion is the mostly used type of product format, it is essential that the scientist knows how to formulate an emulsion which will be water resistant. The HLB (hydrophilic-lipophilic balance) of a formulation has high influence on this characteristic. PMID:22435388

  16. Soil Water Balance and Recharge Monitoring at the Hanford Site - FY09 Status Report

    SciTech Connect

    Rockhold, Mark L.; Saunders, Danielle L.; Strickland, Christopher E.; Waichler, Scott R.; Clayton, Ray E.

    2009-09-28

    Recharge provides the primary driving force for transporting contaminants from the vadose zone to underlying aquifer systems. Quantification of recharge rates is important for assessing contaminant transport and fate and for evaluating remediation alternatives. This report describes the status of soil water balance and recharge monitoring performed by Pacific Northwest National Laboratory at the Hanford Site for Fiscal Year 2009. Previously reported data for Fiscal Years 2004 - 2008 are updated with data collected in Fiscal Year 2009 and summarized.

  17. Carbon dioxide and the stomatal control of water balance and photosynthesis in higher plants

    SciTech Connect

    Taiz, L.; Zeiger, E.; Mawson, B. T.; Cornish, K.; Radin, J. W.; Turcotte, E. L.; Hercovitz, S.; Tallman, G.; Karlsson, P. E.; Bogomolni, R. A.; Talbott, L. D.; Srivastava, A.

    1992-01-01

    Research continued into the investigation of the effects of carbon dioxide on stomatal control of water balance and photosynthesis in higher plants. Topics discussed this period include a method of isolating a sufficient number of guard cell chloroplasts for biochemical studies by mechanical isolation of epidermal peels; the measurement of stomatal apertures with a digital image analysis system; development of a high performance liquid chromatography method for quantification of metabolites in guard cells; and genetic control of stomatal movements in Pima cotton. (CBS)

  18. Terrestrial Water Balances in the Face of Variable Climate over 49 years in Southern Michigan

    NASA Astrophysics Data System (ADS)

    Hamilton, S. K.; Hussain, M. Z.

    2014-12-01

    The difference between precipitation and stream discharge over annual periods provides an indication of the total water loss to evaporation and evapotranspiration. The response of evaporative water loss to climate variability and change affects groundwater recharge, stream flow, and lake levels, and is a topic of ongoing debate in the upper Midwest US region and elsewhere. This study examined the watershed water balance for Augusta Creek, which drains a 95-km2 glacial landscape in southwestern Michigan covered by cropland, grassland, forest, and wetlands. The climate is humid and temperate; between 1964-2012 the water-year precipitation averaged 947 mm and ranged from 695-1386 mm. Comparison of precipitation on the upland watershed to baseflow discharge (USGS data; baseflow estimation by WHAT model) across the 49-year record shows that total evaporative water loss averaged 562 +/- 104 mm and ranged from 385-897 mm, with no apparent trend over the record. The evaporative water loss accounts for a mean (s.d.) of 59 +/- 6% of precipitation (range, 48-70%). Evaporative water loss was positively related to total precipitation (r2 = 0.73), but the percentage of precipitation lost to evaporation was only weakly (r2 = 0.12) related to total precipitation. This water balance approach to infer evaporative water loss compares well with direct measurements in the same watershed since 2009 using eddy covariance (grasslands and crops) and soil moisture monitoring by time-domain reflectometry (grasslands, crops, and forest). Thus the evaporative water loss, which is predominantly by evapotranspiration, is linearly related to total precipitation, leaving a relatively consistent proportion for groundwater recharge and streamflow.

  19. Water balance model for mean annual hydrogen and oxygen isotope distributions in surface waters of the contiguous United States

    NASA Astrophysics Data System (ADS)

    Bowen, Gabriel J.; Kennedy, Casey D.; Liu, Zhongfang; Stalker, Jeremy

    2011-12-01

    The stable H and O isotope composition of river and stream water records information on runoff sources and land-atmosphere water fluxes within the catchment and is a potentially powerful tool for network-based monitoring of ecohydrological systems. Process-based hydrological models, however, have thus far shown limited power to replicate observed large-scale variation in U.S. surface water isotope ratios. Here we develop a geographic information system-based model to predict long-term annual average surface water isotope ratios across the contiguous United States. We use elevation-explicit, gridded precipitation isotope maps as model input and data from a U.S. Geological Survey monitoring program for validation. We find that models incorporating monthly variation in precipitation-evapotranspiration (P-E) amounts account for the majority (>89%) of isotopic variation and have reduced regional bias relative to models that do not consider intra-annual P-E effects on catchment water balance. Residuals from the water balance model exhibit strong spatial patterning and correlations that suggest model residuals isolate additional hydrological signal. We use interpolated model residuals to generate optimized prediction maps for U.S. surface water δ2H and δ18O values. We show that the modeled surface water values represent a relatively accurate and unbiased proxy for drinking water isotope ratios across the United States, making these data products useful in ecological and criminal forensics applications that require estimates of the local environmental water isotope variation across large geographic regions.

  20. Water Balance of Lakes in the Continental Arctic: An Arid Zone Case Study

    NASA Astrophysics Data System (ADS)

    Gibson, J. J.; YI, Y.; Birks, S. J.

    2014-12-01

    Stable isotope mass balance using oxygen-18 and deuterium has been applied to study spatial evaporation and water balance trends across continental northern Canada, a remote region of greater than 275,000 km2 characterized by significant seasonal aridity and strong gradients in hydroclimate and vegetation. Calculated catchment-weighted evaporation losses based on a lake survey in the 1990s were estimated at ~10-15% in tundra areas draining into the Arctic Ocean to as high as 60% in forested subarctic areas draining to the Mackenzie River via Great Bear or Great Slave Lakes. Open-water evaporation was found to generally decrease with increasing latitude, accounting for 5 to 50% of total evapotranspiration. Two long-term studies initiated in the 1990s, and carried on for 20+ years, confirm many of the findings of the initial survey and now provide a complimentary perspective of temporal variations in water balance along two representative string-of-lakes drainages located in boreal and tundra settings. For a tundra watershed, the study reveals important lake-order-dependent patterns of evaporation/inflow, evaporation/evapotranspiration, land-surface-runoff/precipitation and discharge/precipitation. For a boreal watershed, the analysis also reveals that fluctuations in effective drainage area due to intermittent connectivity between lakes during dry periods can be an important driver of downstream isotopic signals.

  1. Assessment of the Water Balance Over France Using Regionalized Turc-Pike Formula for Operational Hydrology

    NASA Astrophysics Data System (ADS)

    LE Lay, M.; Garcon, R.; Gailhard, J.; Garavaglia, F.

    2015-12-01

    With extensive use of hydrological models over a wide range of hydro-climatic contexts, bias in hydro-climatic data may lead to unreliable models and thus hydrological forecasts and projections. This issue is particularly pregnant when considering mountainous areas with great uncertainties on precipitations, or when considering complex unconservative catchments (e.g. karstic systems). The Turc-Pike water balance formula, analogous to the classical Budyko formula, is a simple and efficient mathematical formulation relating long-term average streamflow to long-term average precipitation and potential evaporation. In this study, we propose to apply this framework to assess and eventually adjust the water-balance before calibrating an operational hydrologic model (MORDOR model). Considering a large set of 350 french catchments, the Turc-Pike formula is regionalized based on ecohydrologic criterions to handle various hydro-climatic contexts. This interannual regional model is then applied to assess the water-balance over numerous catchments and various conditions, such as karstic, snow-driven or glaciarized and even anthropized catchments. Results show that it is possible to obtain pretty realistic corrections of meteorological inputs (precipitations, temperature or potential evaporation) or hydrologic surface (or runoff). These corrections can often be confirmed a posteriori by exogenous information. Positive impacts on hydrologic model's calibration are also demonstrated. This methodology is now operational for hydrologic applications at EDF (Electricité de France, French electric utility company), and therefore applied on hundreds of catchments.

  2. Assessment of the water balance over France using regionalized Turc-Pike formula

    NASA Astrophysics Data System (ADS)

    Le Lay, Matthieu; Garçon, Rémy; Gailhard, Joël; Garavaglia, Federico

    2016-04-01

    With extensive use of hydrological models over a wide range of hydro-climatic contexts, bias in hydro-climatic data may lead to unreliable models and thus hydrological forecasts and projections. This issue is particularly pregnant when considering mountainous areas with great uncertainties on precipitations, or when considering complex unconservative catchments (e.g. karstic systems). The Turc-Pike water balance formula, analogous to the classical Budyko formula, is a simple and efficient mathematical formulation relating long-term average streamflow to long-term average precipitation and potential evaporation. In this study, we propose to apply this framework to assess and eventually adjust the water-balance before calibrating an operational hydrologic model (MORDOR model). Considering a large set of 350 french catchments, the Turc-Pike formula is regionalized based on ecohydrologic criterions to handle various hydro-climatic contexts. This interannual regional model is then applied to assess the water-balance over numerous catchments and various conditions, such as karstic, snow-driven or glaciarized and even anthropized catchments. Results show that it is possible to obtain pretty realistic corrections of meteorological inputs (precipitations, temperature or potential evaporation) or hydrologic surface (or runoff). These corrections can often be confirmed a posteriori by exogenous information. Positive impacts on hydrologic model's calibration are also demonstrated. This methodology is now operational for hydrologic applications at EDF (Electricité de France, French electric utility company), and therefore applied on hundreds of catchments.

  3. Development of a multicomponent force and moment balance for water tunnel applications, volume 2

    NASA Technical Reports Server (NTRS)

    Suarez, Carlos J.; Malcolm, Gerald N.; Kramer, Brian R.; Smith, Brooke C.; Ayers, Bert F.

    1994-01-01

    The principal objective of this research effort was to develop a multicomponent strain gauge balance to measure forces and moments on models tested in flow visualization water tunnels. Static experiments (which are discussed in Volume 1 of this report) were conducted, and the results showed good agreement with wind tunnel data on similar configurations. Dynamic experiments, which are the main topic of this Volume, were also performed using the balance. Delta wing models and two F/A-18 models were utilized in a variety of dynamic tests. This investigation showed that, as expected, the values of the inertial tares are very small due to the low rotating rates required in a low-speed water tunnel and can, therefore, be ignored. Oscillations in pitch, yaw and roll showed hysteresis loops that compared favorably to data from dynamic wind tunnel experiments. Pitch-up and hold maneuvers revealed the long persistence, or time-lags, of some of the force components in response to the motion. Rotary-balance experiments were also successfully performed. The good results obtained in these dynamic experiments bring a whole new dimension to water tunnel testing and emphasize the importance of having the capability to perform simultaneous flow visualization and force/moment measurements during dynamic situations.

  4. Development of a multicomponent force and moment balance for water tunnel applications, volume 2

    NASA Astrophysics Data System (ADS)

    Suarez, Carlos J.; Malcolm, Gerald N.; Kramer, Brian R.; Smith, Brooke C.; Ayers, Bert F.

    1994-12-01

    The principal objective of this research effort was to develop a multicomponent strain gauge balance to measure forces and moments on models tested in flow visualization water tunnels. Static experiments (which are discussed in Volume 1 of this report) were conducted, and the results showed good agreement with wind tunnel data on similar configurations. Dynamic experiments, which are the main topic of this Volume, were also performed using the balance. Delta wing models and two F/A-18 models were utilized in a variety of dynamic tests. This investigation showed that, as expected, the values of the inertial tares are very small due to the low rotating rates required in a low-speed water tunnel and can, therefore, be ignored. Oscillations in pitch, yaw and roll showed hysteresis loops that compared favorably to data from dynamic wind tunnel experiments. Pitch-up and hold maneuvers revealed the long persistence, or time-lags, of some of the force components in response to the motion. Rotary-balance experiments were also successfully performed. The good results obtained in these dynamic experiments bring a whole new dimension to water tunnel testing and emphasize the importance of having the capability to perform simultaneous flow visualization and force/moment measurements during dynamic situations.

  5. U.S. Biofuel Policies and Domestic Shifts in Agricultural Land Use and Water Balances

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Policies promoting domestic biofuels production could lead to significant changes in cropping patterns. Types of direct and indirect land use change include: switching among crops (displacement), expanding cropped area (extensification), and altering water/soil management practices (e.g. irrigation, tillage) (intensification). Most studies of biofuels water use impacts calculate the water intensity of biofuels in liters of irrigated/total evapotranspired water per unit energy of biofuels. But estimates based on this approach are sensitive to assumptions (e.g. co-product allocation, system boundaries), and do not convey policy-relevant information, as highlighted by the issue of land use change. We address these shortcomings by adopting a scenario-based approach that combines economic modeling with crop-water modeling of major crops and biofuel feedstocks. This allows us to holistically compare differences in water balances across policy scenarios in an integrated economic/agricultural system. We compare high spatial resolution water balance estimates under three hypothetical policy scenarios: 1) a counterfactual no-policy scenario, 2) modified Renewable Fuels Standard mandates (M-RFS2), & 3) a national Low Carbon Fuel Standard plus a modified RFS2 scenario (LCFS+RFS2). Differences between scenarios in crop water balances (i.e. transpiration, evaporation, runoff, groundwater infiltration, & irrigation) are regional and are a function of changes in land use patterns (i.e. displacement, intensification, & extensification), plus variation in crop water-use characteristics. Cropped land area increases 6.2% and 1.6% under M-RFS2 and LCFS+RFS2 scenarios, respectively, by 2030. Both policy scenarios lead to reductions in net irrigation volumes nationally compared to the no-policy scenario, though more irrigation occurs in regions of the Midwest and West. The LCFS+RFS2 reduces net irrigation water use by 3.5 times more than M-RFS2. However, both policies drive

  6. Estimating rainfall and water balance over the Okavango River Basin for hydrological applications

    NASA Astrophysics Data System (ADS)

    Wilk, Julie; Kniveton, Dominic; Andersson, Lotta; Layberry, Russell; Todd, Martin C.; Hughes, Denis; Ringrose, Susan; Vanderpost, Cornelis

    2006-11-01

    SummaryA historical database for use in rainfall-runoff modeling of the Okavango River Basin in Southwest Africa is presented. The work has relevance for similar data-sparse regions. The parameters of main concern are rainfall and catchment water balance, which are key variables for subsequent studies of the hydrological impacts of development and climate change. Rainfall estimates are based on a combination of in situ gauges and satellite sources. Rain gauge measurements are most extensive from 1955 to 1972, after which they are drastically reduced due to the Angolan civil war. The sensitivity of the rainfall fields to spatial interpolation techniques and the density of gauges were evaluated. Satellite based rainfall estimates for the basin are developed for the period from 1991 onwards, based on the Tropical Rainfall Measuring Mission (TRMM) and Special Sensor Microwave Imager (SSM/I) datasets. The consistency between the gauges and satellite estimates was considered. A methodology was developed to allow calibration of the rainfall-runoff hydrological model against rain gauge data from 1960 to 1972, with the prerequisite that the model should be driven by satellite derived rainfall products from 1990 onwards. With the rain gauge data, addition of a single rainfall station (Longa) in regions where stations earlier were lacking was more important than the chosen interpolation method. Comparison of satellite and gauge rainfall outside the basin indicated that the satellite overestimates rainfall by 20%. A non-linear correction was derived by fitting the rainfall frequency characteristics to those of the historical rainfall data. This satellite rainfall dataset was found satisfactory when using the Pitman rainfall-runoff model (Hughes, D., Andersson, L., Wilk, J., Savenije, H.H.G., this issue. Regional calibration of the Pitman model for the Okavango River. Journal of Hydrology). Intensive monitoring in the region is recommended to increase accuracy of the

  7. Geochemical mass-balance relationships for selected ions in precipitation and stream water, Catoctin Mountains, Maryland.

    USGS Publications Warehouse

    Katz, B.G.; Bricker, O.P.; Kennedy, M.M.

    1985-01-01

    Results of a study of input/output mass balances for major ions based on the chemical composition of precipitation and stream-water, geochemical reactions with different loading rates of hydrogen ion, and watershed processes influencing the chemical character of stream-waters in two small watershed areas are reported with a view to predicting the effect of additions of acidic rain to the watershed systems. Geochemical weathering processes account for the observed changes in the chemistry of stream flow. Although present in bedrock in extremely small quantities, calcite plays an important role in neutralization of the total hydrogen-ion input.-M.S.

  8. Effect of long-term simulated weightlessness on surfactant and water balance in mouse lungs.

    PubMed

    Bryndina, I G; Vasilieva, N N; Krivonogova, Yu A; Baranov, V M

    2013-07-01

    Weightlessness produces adaptive and maladaptive changes in the respiratory system. We assessed the effects of 30-day antiorthostatic hanging as a model of microgravity on the water balance in the lungs and surface activity and phospholipid composition of pulmonary surfactant in C57Bl/6 mice. Long-term antiorthostatic hanging increased water content in the lungs and reduced surface-active properties of the surfactant. This was accompanied by an increase in the content of alveolar phospholipids and changes in their fractional composition (increase in the relative content of lysophosphatidylcholine and phosphatidylethanolamine). PMID:24137589

  9. Potential Foraging Decisions by a Desert Ungulate to Balance Water and Nutrient Intake in a Water-Stressed Environment.

    PubMed

    Gedir, Jay V; Cain, James W; Krausman, Paul R; Allen, Jamison D; Duff, Glenn C; Morgart, John R

    2016-01-01

    Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8-55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

  10. Potential foraging decisions by a desert ungulate to balance water and nutrient intake in a water-stressed environment

    USGS Publications Warehouse

    Gedir, Jay V.; Cain, James W.; Krausman, Paul R.; Allen, Jamison D.; Duff, Glenn C.; Morgart, John R.

    2016-01-01

    Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8–55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

  11. Potential Foraging Decisions by a Desert Ungulate to Balance Water and Nutrient Intake in a Water-Stressed Environment

    PubMed Central

    Gedir, Jay V.; Cain, James W.; Krausman, Paul R.; Allen, Jamison D.; Duff, Glenn C.

    2016-01-01

    Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8–55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

  12. Latent Heat Flux Estimate Through an Energy Water Balance Model and Land Surface Temperature from Remote Sensing

    NASA Astrophysics Data System (ADS)

    Corbari, Chiara; Sobrino, Jose A.; Mancini, Marco; Hidalgo, Victoria

    2011-01-01

    Soil moisture plays a key role in the terrestrial water cycle and is responsible for the partitioning of precipitation between runoff and infiltration. Moreover, surface soil moisture controls the redistribution of the incoming solar radiation on land surface into sensible and latent heat fluxes. Recent developments have been made to improve soil moisture dynamics predictions with hydrologic land surface models (LSMs) that compute water and energy balances between the land surface and the low atmosphere. However, most of the time soil moisture is confined to an internal numerical model variable mainly due to its intrinsic space and time variability and to the well known difficulties in assessing its value from remote sensing as from in situ measurements. In order to exploit the synergy between hydrological distributed models and thermal remote sensed data, FEST-EWB, a land surface model that solves the energy balance equation, was developed. In this hydrological model, the energy budget is solved looking for the representative thermodynamic equilibrium temperature (RET) defined as the land surface temperature that closes the energy balance equation. So using this approach, soil moisture is linked to the latent heat flux and then to LST. In this work the relationship between land surface temperature and soil moisture is analysed using LST from AHS (airborne hyperspectral scanner), with a spatial resolution of 2-4 m, LST from MODIS, with a spatial resolution of 1000 m, and thermal infrared radiometric ground measurements that are compared with the thermodynamic equilibrium temperature from the energy water balance model. Moreover soil moisture measurements were carried out during the airborne overpasses and then compared with SM from the hydrological model. An improvement of this well known inverse relationship between soil moisture and land surface temperature is obtained when the thermodynamic approach is used. The analysis of the scale effects of the different

  13. Balancing ballistic protection against physiological strain: evidence from laboratory and field trials.

    PubMed

    Taylor, Nigel A S; Burdon, Catriona A; van den Heuvel, Anne M J; Fogarty, Alison L; Notley, Sean R; Hunt, Andrew P; Billing, Daniel C; Drain, Jace R; Silk, Aaron J; Patterson, Mark J; Peoples, Gregory E

    2016-02-01

    This project was based on the premise that decisions concerning the ballistic protection provided to defence personnel should derive from an evaluation of the balance between protection level and its impact on physiological function, mobility, and operational capability. Civilians and soldiers participated in laboratory- and field-based studies in which ensembles providing five levels of ballistic protection were evaluated, each with progressive increases in protection, mass (3.4-11.0 kg), and surface-area coverage (0.25-0.52 m(2)). Physiological trials were conducted on volunteers (N = 8) in a laboratory, under hot-dry conditions simulating an urban patrol: walking at 4 km·h(-1) (90 min) and 6 km·h(-1) (30 min or to fatigue). Field-based trials were used to evaluate tactical battlefield movements (mobility) of soldiers (N = 31) under tropical conditions, and across functional tests of power, speed, agility, endurance, and balance. Finally, trials were conducted at a jungle training centre, with soldiers (N = 32) patrolling under tropical conditions (averaging 5 h). In the laboratory, work tolerance was reduced as protection increased, with deep-body temperature climbing relentlessly. However, the protective ensembles could be grouped into two equally stressful categories, each providing a different level of ballistic protection. This outcome was supported during the mobility trials, with the greatest performance decrement evident during fire and movement simulations, as the ensemble mass was increased (-2.12%·kg(-1)). The jungle patrol trials similarly supported this outcome. Therefore, although ballistic protection does increase physiological strain, this research has provided a basis on which to determine how that strain can be balanced against the mission-specific level of required personal protection. PMID:26771198

  14. Balancing the source terms in a SPH model for solving the shallow water equations

    NASA Astrophysics Data System (ADS)

    Xia, Xilin; Liang, Qiuhua; Pastor, Manuel; Zou, Weilie; Zhuang, Yan-Feng

    2013-09-01

    A shallow flow generally features complex hydrodynamics induced by complicated domain topography and geometry. A numerical scheme with well-balanced flux and source term gradients is therefore essential before a shallow flow model can be applied to simulate real-world problems. The issue of source term balancing has been exhaustively investigated in grid-based numerical approaches, e.g. discontinuous Galerkin finite element methods and finite volume Godunov-type methods. In recent years, a relatively new computational method, smooth particle hydrodynamics (SPH), has started to gain popularity in solving the shallow water equations (SWEs). However, the well-balanced problem has not been fully investigated and resolved in the context of SPH. This work aims to discuss the well-balanced problem caused by a standard SPH discretization to the SWEs with slope source terms and derive a corrected SPH algorithm that is able to preserve the solution of lake at rest. In order to enhance the shock capturing capability of the resulting SPH model, the Monotone Upwind-centered Scheme for Conservation Laws (MUSCL) is also explored and applied to enable Riemann solver based artificial viscosity. The new SPH model is validated against several idealized benchmark tests and a real-world dam-break case and promising results are obtained.

  15. Water and Heat Balance Model for Predicting Drainage Below the Plant Root Zone

    Energy Science and Technology Software Center (ESTSC)

    1989-11-01

    UNSAT-H Version 2.0 is a one-dimensional model that simulates the dynamic processes of infiltration, drainage, redistribution, surface evaporation, and the uptake of water from soil by plants. The model was developed for assessing the water dynamics of arid sites used or proposed for near-surface waste disposal. In particular, the model is used for simulating the water balance of cover systems over buried waste and for estimating the recharge rate (i.e., the drainage rate beneath themore » plant root zone when a sizable vadose zone is present). The mathematical base of the model are Richards'' equation for water flow, Ficks'' law for vapor diffusion, and Fouriers law for heat flow. The simulated profile can be homogeneous or layered. The boundary conditions can be controlled as either constant (potential or temperature) or flux conditions to reflect actual conditions at a given site.« less

  16. Large-eddy simulation in an anelastic framework with closed water and entropy balances

    NASA Astrophysics Data System (ADS)

    Pressel, Kyle G.; Kaul, Colleen M.; Schneider, Tapio; Tan, Zhihong; Mishra, Siddhartha

    2015-09-01

    A large-eddy simulation (LES) framework is developed for simulating the dynamics of clouds and boundary layers with closed water and entropy balances. The framework is based on the anelastic equations in a formulation that remains accurate for deep convection. As prognostic variables, it uses total water and entropy, which are conserved in adiabatic and reversible processes, including reversible phase changes of water. This has numerical advantages for modeling clouds, in which reversible phase changes of water occur frequently. The equations of motion are discretized using higher-order weighted essentially nonoscillatory (WENO) discretization schemes with strong stability preserving time stepping. Numerical tests demonstrate that the WENO schemes yield simulations superior to centered schemes, even when the WENO schemes are used at coarser resolution. The framework is implemented in a new LES code written in Python and Cython, which makes the code transparent and easy to use for a wide user group.

  17. Water balance and kidney function in the least shrew (Cryptotis parva).

    PubMed

    Goldstein, David L; Newland, Stacy

    2004-09-01

    We assessed renal function in least shrews (Cryptotis parva, body mass 4.7 g) within the context of overall water balance. The glomerular filtration rate (GFR) of shrews with unlimited food and water was 2.4 ml/h, about 60% of the rate predicted from body mass. Of this, about 3% (0.075 ml/h) was excreted as urine with an osmolality of 1944 mmol/kg, 5.5 times plasma osmolality. Shrews had a total water turnover (5 ml/day) two to three times higher than expected from allometry for a small mammal of this size. Water influx was partitioned among preformed water from food (65%), drinking (16%), and metabolic water (20%). Water efflux was divided among urine flow (35%), fecal water loss (estimated as 23%), and evaporation (by difference, 42%). Least shrews had a high water turnover rate and relatively high urine flow rate (UFR); this likely reflects a combination of factors, including high metabolism, active lifestyle, and wet diet. PMID:15471683

  18. Anteroposterior dynamic balance reactions induced by circular translation of the visual field.

    PubMed

    Séverac Cauquil, A; Bessou, M; Dupui, P; Bessou, P

    1996-01-01

    The anteroposterior sway of subjects under conditions of spontaneous dynamic balance on a wobbly platform was measured during visual stimulation by a visual target executing a circular trajectory in the frontal plane. The target was either a component of the whole moving visual scene or moving on a stationary background. With the former stimulation, obtained through the use of rotating prismatic glasses, every point of the visual field appeared to describe a circular trajectory around its real position so that the whole visual field appeared to be circularly translated, undistorted, inducing a binocular pursuit movement. Under these conditions, stereotyped anteroposterior dynamic balance reactions synchronous with the position of the stimulus were elicited. The latter stimulation consisted of pursuing a luminous target describing a trajectory similar to that of the fixation point seen through the rotating prisms on the same, this time stable, visual background. Although pursuit eye movements were comparable, as demonstrated by electro-oculographic recordings, no stereotyped equilibration reaction was induced. It is concluded that the translatory motion of the background image on the retina in the latter experiments contributed to the body's stability as well as to the perception of a stable environment. PMID:8865085

  19. Water balance-based estimation of groundwater recharge in the Lake Chad Basin

    NASA Astrophysics Data System (ADS)

    Babamaaji, R. A.; Lee, J.

    2012-12-01

    Lake Chad Basin (LCB) has experienced drastic changes of land cover and poor water management practices during the last 50 years. The successive droughts in the 1970s and 1980s resulted in the shortage of surface water and groundwater resources. This problem of drought and shortage of water has a devastating implication on the natural resources of the Basin with great consequence on food security, poverty reduction and quality of life of the inhabitants in the LCB. Therefore, understanding the change of land use and its characteristics must be a first step to find how such changes disturb the water cycle especially the groundwater in the LCB. The abundance of groundwater is affected by the climate change through the interaction with surface water, such as lakes and rivers, and vertical recharge through an infiltration process. Quantifying the impact of climate change on the groundwater resource requires not only reliable forecasting of changes in the major climatic variables, but also accurate estimation of groundwater recharge. Spatial variations in the land use/land cover, soil texture, topographic slope, and meteorological conditions should be accounted for in the recharge estimation. In this study, we employed a spatially distributed water balance model WetSpass to simulate a long-term average change of groundwater recharge in the LCB of Africa. WetSpass is a water balance-based model to estimate seasonal average spatial distribution of surface runoff, evapotranspiration, and groundwater recharge. The model is especially suitable for studying the effect of land use/land cover change on the water regime in the LCB. The present study describes the concept of the model and its application to the development of recharge map of the LCB.

  20. Visualization by light transmission of oil and water contents in transient two-phase flow fields

    NASA Astrophysics Data System (ADS)

    Darnault, Christophe J. G.; Throop, James A.; DiCarlo, David A.; Rimmer, Alon; Steenhuis, Tammo S.; Parlange, J.-Yves

    1998-06-01

    The difficulty of determining transient fluid contents in a soil-oil-water system is hampering an understanding of the system's flow characteristics. In this paper, we describe a light transmission method (LTM) which can rapidly obtain oil and water contents throughout a large two-dimensional flow field of silica sand. By appropriately coloring the water with 0.005% FD&C blue #1, the hue of the transmitted light is found to be directly related to the water content within the porous media. The hue provides a high resolution measurement of the water and oil contents in transient flow fields (such as unstable flow). Evaluation of the reliability of LTM was assessed by checking the mass balance for a known water injection and its utility in visualizing a whole flow field was exemplified for unstable fingered flow by comparing fluid contents to those obtained with synchrotron X-ray radiation.

  1. Mapping land water and energy balance relations through conditional sampling of remote sensing estimates of atmospheric forcing and surface states

    NASA Astrophysics Data System (ADS)

    Farhadi, Leila; Entekhabi, Dara; Salvucci, Guido

    2016-04-01

    In this study, we develop and apply a mapping estimation capability for key unknown parameters that link the surface water and energy balance equations. The method is applied to the Gourma region in West Africa. The accuracy of the estimation method at point scale was previously examined using flux tower data. In this study, the capability is scaled to be applicable with remotely sensed data products and hence allow mapping. Parameters of the system are estimated through a process that links atmospheric forcing (precipitation and incident radiation), surface states, and unknown parameters. Based on conditional averaging of land surface temperature and moisture states, respectively, a single objective function is posed that measures moisture and temperature-dependent errors solely in terms of observed forcings and surface states. This objective function is minimized with respect to parameters to identify evapotranspiration and drainage models and estimate water and energy balance flux components. The uncertainty of the estimated parameters (and associated statistical confidence limits) is obtained through the inverse of Hessian of the objective function, which is an approximation of the covariance matrix. This calibration-free method is applied to the mesoscale region of Gourma in West Africa using multiplatform remote sensing data. The retrievals are verified against tower-flux field site data and physiographic characteristics of the region. The focus is to find the functional form of the evaporative fraction dependence on soil moisture, a key closure function for surface and subsurface heat and moisture dynamics, using remote sensing data.

  2. A Multifunctional Surface That Simultaneously Balances Hydrophilic Enzyme Catalysis and Hydrophobic Water Repellency.

    PubMed

    Lawton, Timothy J; Uzarski, Joshua R; Filocamo, Shaun F

    2016-08-16

    The compatibility of multiple functions at a single interface is difficult to achieve, but is even more challenging when the functions directly counteract one another. This study provides insight into the creation of a simultaneously multifunctional surface formed by balancing two orthogonal functions; water repellency and enzyme catalysis. A partially fluorinated thiol is used to impart bulk hydrophobicity on the surface, and an N-hydroxysuccinimide ester-terminated thiol provides a specific anchoring sites for the covalent enzyme attachment. Different ratios of the two thiols are mixed together to form amphiphilic self-assembled monolayers, which are characterized with polarization-modulation infrared reflection-absorption spectroscopy and contact angle goniometry. The enzyme activity is measured by a fluorescence assay. With the results collected here, specific surface compositions are identified at which the orthogonal functions of water repellency and enzyme catalysis are balanced and exist simultaneously. An understanding of how to effectively balance orthogonal functions at surfaces can be extended to a number of higher-scale applications. PMID:27406598

  3. Testing the hydrological water balance model criteria using TDR measurements and micrometeorological data

    NASA Astrophysics Data System (ADS)

    Licciardello, Feliciana; Villani, Giulia; Pasotti, Luigi; Consoli, Simona

    2014-05-01

    In arid and semi-arid regions, the availability of water is a major limitation on crop production due to insufficient rainfall to compensate the evaporative losses by crops. Improvements in water management in irrigated areas and adequate irrigation scheduling are essential also to increase the sustainability of irrigated agriculture. In particular, reliable estimates of soil moisture changes in agricultural soils may help the available water management under scarce conditions. In the last two decades this issue has induced the development of physically based models for simulating the different components of the water balance. These models, often developed in specific environmental or agronomic conditions, needs to be further validated. The study aims at assessing the performance of the physically based CRITERIA model to simulate the hydrological water balance of agricultural soils. The model, developed by the ARPA-SIMC (Hydro-meteorological service of the Emilia-Romagna region, Italy), includes procedures and conceptual models for the simulation of infiltration, evapotranspiration, runoff, deep drainage, capillary rise, canopy expansion and root deepening. The model consists of (i) an algorithm for coupling the surface flow components (i.e. Richards equation), with simultaneous solution of the conservation equation, (ii) various modules which may it applicable to various topographical and environmental conditions (i.e. Penman-Monteith equation for crop evapotranspiration fluxes among others). In the model, the soil water retention data are described by the van Genuchten equation, with the hydraulic conductivity calculated by the Mualem model. CRITERIA, that includes a database with several crops, was already tested in north Italy and in USA but never in typical Mediterranean semi-arid environments where citrus orchards growth. In order to verify the performance of CRITERIA, data from an experimental citrus orchard located in Eastern Sicily, Italy, were used to

  4. Simulating the regional water balance through hydrological model based on TRMM satellite rainfall data

    NASA Astrophysics Data System (ADS)

    Li, D.; Ding, X.; Wu, J.

    2015-02-01

    Spatial rainfall is a key input to Distributed Hydrological Models, which is the most important limitation for the accuracy of hydrological models. Model performance and uncertainty could increase when rain gauge is sparse. Satellite-based precipitation products would be an alternative to ground-based rainfall estimates in present and the foreseeable future, however, it is necessary to evaluate the products before further implication. The objective of this paper is to provide assessments of: (a) the Tropical Rainfall Measuring Mission (TRMM) rainfall product using gauge data, (b) the TRMM rainfall as forcing data for hydrological simulation, and (c) the role of satellite data in calculating water balance and water management. TRMM rainfall data show reasonable performances at monthly and annual scales, fitting well with surface observation-based histogram of precipitation. Satisfactory performances in monthly runoff simulation (NS = 0.50 ~ 0.70, R2 = 0.73 ~ 0.85) observed in our study indicate that the TRMM rainfall data have potential applications in driving hydrological model, water balance analysis, and basin water resource management in developing countries or remote locations, where precipitation gauges are scare.

  5. Water balance and locomotor performance in three species of neotropical toads that differ in geographical distribution.

    PubMed

    Titon, Braz; Navas, Carlos Arturo; Jim, Jorge; Gomes, Fernando Ribeiro

    2010-05-01

    Water availability in the environment is a fundamental factor in determining the limits of geographical distribution and the evolution of the physiological characters associated to water balance in anurans. In this paper, we compare some aspects of water balance and the sensitivity of locomotor performance to dehydration at different temperatures for three species of toads from the genus Rhinella, with different levels of dependence on forested environments. Results show patterns associated to interspecific differences in both geographical distribution and time of seasonal reproduction. Sensitivity of locomotor performance to dehydration was lower at low temperatures for R. icterica, the species that are reproductively active during winter and lower at intermediate temperatures for R. schneideri, the species that reproduces mostly during spring, suggesting a pattern of thermal adaptation of locomotor performance for these species. Otherwise, R. ornata, a species with broader reproductive season, shows high sensitivity of locomotor performance to dehydration at all temperatures tested, suggesting a stronger relation of breeding activity with patterns of rainfall than temperature variation. Furthermore, the low rates of water uptake of R. ornata may pose restrictions on the occupation of open areas by this species. PMID:20096361

  6. A modeling framework to assess water and nitrate balances in the Western Bug river basin, Ukraine

    NASA Astrophysics Data System (ADS)

    Tavares Wahren, F.; Helm, B.; Schumacher, F.; Pluntke, T.; Feger, K.-H.; Schwärzel, K.

    2012-12-01

    The objective of this study was to assess the utility of the eco-hydrological SWAT model (Soil and Water Assessment Tool, Arnold et al., 1998) for representing water balance and nitrate fluxes given limited input and calibration data. The investigated catchment is located in Western Ukraine with an area of approximately 2616 km2. Land use is currently dominated by agriculture with significant areas of pasture, and has undergone a high degree of changes in land-use and agricultural practice since the end of the Soviet Union. Model application produced a fitted water balance (calibration: R2 = 0.52, NS = 0.46; validation: R2 = 0.47, NS = 0.51) and plausible ranges and dynamics of nitrate in stream loadings. Groundwater parameters were found to be highly sensitive. The results indicate that SWAT is an appropriate tool for water resource investigations in the Western Bug catchment, and can provide a useful tool for further eco-hydrologic research in the region (i.e. diffuse pollution impacts).

  7. Simulating the fate of water in field soil crop environment

    NASA Astrophysics Data System (ADS)

    Cameira, M. R.; Fernando, R. M.; Ahuja, L.; Pereira, L.

    2005-12-01

    grain and forage corn, respectively. Soil water was predicted with an efficiency ranging from 50 to 95% for the silty loam soil and between 56 and 72% for the sandy soil. The purposed calibration procedure allowed the model to predict crop development, yield and the water balance terms, with accuracy that is acceptable in practical applications for complex and spatially variable field conditions. An iterative method was required to account for the strong interaction between the different model components, based upon detailed experimental data on soils and crops.

  8. The isotopic composition of water vapor as a tracer of water balance in the TTL

    NASA Astrophysics Data System (ADS)

    Bolot, Maximilien; Moyer, Elisabeth; Legras, Bernard; Walker, Kaley; Boone, Chris; Bernath, Peter

    2015-04-01

    The relatively small amount of water vapor in the tropical tropopause layer (TTL) region is of disproportionate radiative importance, and projections of changes in TTL water are hampered by poor understanding of its sources and controls. We show here that the profile of the isotopic composition of water vapor can be used to quantify the contribution of various processes to the water budget of the region: convective sources of water, dehydration via in situ cirrus formation and sedimentation, and moistening from mixing with extratropical air. We combine these processes into a simple model for the isotopic ratio of TTL water vapor. By fitting the model parameters to reproduce an averaged tropical profile of water vapor isotopic ratio in the TTL, we can retrieve the convective contribution to TTL water vapor. Using isotopic measurements from the ACE-FTS solar-occultation instrument, we show that convective injection of water vapor must provide a significant contribution to TTL water vapor. That contribution in turn has large radiative effects, because it increases the production of in-situ cirrus over what would be inferred from large-scale uplift alone, by a factor 2-10 over the TTL (15-17.5 km).

  9. Global estimation of evapotranspiration using a leaf area index-based surface energy and water balance model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies of global hydrologic cycles, carbon cycles and climate change are greatly facilitated when global estimates of evapotranspiration (E) are available. We have developed an air-relative-humidity-based two-source (ARTS) E model that simulates the surface energy balance, soil water balance, and e...

  10. Deforestation offsets water balance changes due to climate variability in the Xingu River in eastern Amazonia

    NASA Astrophysics Data System (ADS)

    Panday, Prajjwal K.; Coe, Michael T.; Macedo, Marcia N.; Lefebvre, Paul; Castanho, Andrea D. de Almeida

    2015-04-01

    Deforestation reduced forest cover in Brazil's Xingu River Basin (XB; area: 510,000 km2) from 90% of the basin in the 1970s to 75% in the 2000s. Such large-scale land cover changes can substantially alter regional water budgets, but their influence can be difficult to isolate from that of natural climate variability. In this study, we estimate changes to the XB water balance from the 1970s to the 2000s due to climate variations and deforestation, using a combination of long-term observations of rainfall and discharge; satellite-based estimates of evapotranspiration (MODIS) and surface water storage (GRACE); and numerical modeling estimates (IBIS) of water budget components (evapotranspiration, soil moisture, and discharge). Model simulations over this period suggest that climate variations alone accounted for a -82 mm decrease (mean per unit area) in annual discharge (-14%, from 8190 m3 s-1 to 7806 m3 s-1), due to a -2% decrease in precipitation and +3% increase in evapotranspiration. Deforestation alone caused a +34 mm increase in annual discharge (+6%), as a result of a -3% decrease in evapotranspiration and +1% increase in soil moisture across the XB. Climate variability and land cover change thus had opposite effects on the XB water balance, with climate effects masking deforestation-induced changes to the water budget. Protected areas, which cover 55% of the basin, have helped to mitigate the effects of past deforestation on water recycling in the Xingu. However, our results suggest that continued deforestation outside protected areas could trigger changes of sufficient magnitude to offset climate variability.

  11. Strike a Balance: Optimization of Backbone Torsion Parameters of AMBER Polarizable Force Field for Simulations of Proteins and Peptides

    PubMed Central

    WANG, ZHI-XIANG; ZHANG, WEI; WU, CHUN; LEI, HONGXING; CIEPLAK, PIOTR; DUAN, YONG

    2014-01-01

    Based on the AMBER polarizable model (ff02), we have reoptimized the parameters related to the main-chain (Φ, Ψ) torsion angles by fitting to the Boltzmann-weighted average quantum mechanical (QM) energies of the important regions (i.e., β, PII, αR, and αL regions). Following the naming convention of the AMBER force field series, this release will be called ff02pol.rl The force field has been assessed both by energetic comparison against the QM data and by the replica exchange molecular dynamics simulations of short alanine peptides in water. For Ace-Ala-Nme, the simulated populations in the β, PII and αR regions were approximately 30, 43, and 26%, respectively. For Ace-(Ala)7-Nme, the populations in these three regions were approximately 24, 49, and 26%. Both were in qualitative agreement with the NMR and CD experimental conclusions. In comparison with the previous force field, ff02pol.rl demonstrated good balance among these three important regions. The optimized torsion parameters, together with those in ff02, allow us to carry out simulations on proteins and peptides with the consideration of polarization. PMID:16526038

  12. Spacebased Observations of Oceanic Influence on the Annual Variation of South American Water Balance

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Xie, Xiaosu; Tang, Wenqing; Zlotnicki, Victor

    2006-01-01

    The mass change of South America (SA) continent measured by the Gravity Recovery and Climate Experiment (GRACE) imposes a constraint on the uncertainties in estimating the annual variation of rainfall measured by Tropical Rain Measuring Mission (TRMM) and ocean moisture influx derived from QuikSCAT data. The approximate balance of the mass change rate with the moisture influx less climatological river discharge, in agreement with the conservation principle, bolsters not only the credibility of the spacebased measurements, but supports the characterization of ocean's influence on the annual variation of continental water balance. The annual variation of rainfall is found to be in phase with the mass change rate in the Amazon and the La Plata basins, and the moisture advection across relevant segments of the Pacific and Atlantic coasts agrees with the annual cycle of rainfall in the two basins and the Andes mountains.

  13. A continental scale water balance model: a GIS-approach for Southern Africa

    NASA Astrophysics Data System (ADS)

    Alemaw, B. F.; Chaoka, T. R.

    A distributed GIS-based hydrological model is developed using GIS and computational hydrology techniques. The model is based on water balance consideration of the surface and subsurface processes. The surface water balance processes include precipitation infiltration, overland runoff, evapo-transpiration and canopy surface interception losses on daily time steps; The subsurface process considers soil moisture accounting on a monthly basis. The model was used to estimate generated runoff from matrix of specific geo-referenced grids representing Southern Africa. All regional and seasonal dispensation of water balances have been based on standard GIS formats for storage, spatial display and interpretation of results. Considering the 1961-1990 climatic period, we have mapped the regional variation of the mean annual soil moisture (SM), actual evapo-transpiration (AET), and generated runoff (ROF) across Southern Africa or known as the SADC region. The model estimates the mean SM of the region to be about 148 mm/year. There is a wide spatial range in the distribution of SM over the region due to the fact that the absolute soil moisture is dependent on the water retention properties of the soils considered across the region. The model prediction of the mean annual AET in the region reaches a maximum of 1500 mm, with mean 420 mm. The mean annual generated runoff from the land catchment in the region is about 151 mm/year although there is a significant inter-regional variation among the SADC countries, which is a function of the variation in the vegetation cover, soil and climate variation. Lower runoff regimes are dominant in arid areas in Botswana, Namibia and south-western part of the Republic of South Africa. Higher runoff regimes are the Northern and Western Tanzania, along the east coastal portions of Mozambique, central Mozambique, western Zambia and Malawi.

  14. Applying fog climatology to water balance modeling for the Russian River watershed, California

    NASA Astrophysics Data System (ADS)

    Flint, L. E.; Torregrosa, A.; Flint, A. L.; Combs, C.; Peters, J.

    2013-12-01

    Coastal fog modifies the hydrodynamic and thermodynamic properties of California watersheds with the greatest impact on ecosystem functioning during arid summer months. Lowered maximum temperatures that result from inland penetration of marine fog are probably adequately captured by meteorological temperature measurements, however the hydrologic impacts of lowered rates of evapotranspiration due to fog drip, increased relative humidity, and other factors associated with fog events are more difficult to gage. Fog products, such as those derived from National Weather Service (NWS) satellite data streams provide high frequency (up to every 15 min) views of low cloud cover and have the potential to improve water balance models. Even slight improvements in water balance calculations can benefit urban water managers and agricultural irrigation. The high frequency of data output from the NWS Geostationary Operational Environmental Satellite (GOES) provides the opportunity to explore various strategies for data input. This pilot project sought to explore which time interval provided useful results and if empirical relationships with climate and water balance variables could be developed. Plant ecophysiological mechanisms of daytime photosynthesis suggest that a day/night differentiation on a monthly basis is adequate. To explore this hypothesis, we examined the output for the Russian River watershed from the USGS Basin Characterization Model to compare runoff, recharge, potential evapotranspiration, and actual evapotranspiration with stream gage data under low, medium, and high fog hour conditions over 10 years (1999-2009) and differentiating fog events into daytime and nighttime versus a 24-hour compilation on a daily, monthly, and seasonal basis. Our data suggest that a daily time-step is required to adequately incorporate the hydrologic effect of fog.

  15. Water-balance and groundwater-flow estimation for an arid environment: San Diego region, California

    NASA Astrophysics Data System (ADS)

    Flint, L. E.; Flint, A. L.; Stolp, B. J.; Danskin, W. R.

    2012-03-01

    The coastal-plain aquifer that underlies the San Diego City metropolitan area in southern California is a groundwater resource. The understanding of the region-wide water balance and the recharge of water from the high elevation mountains to the east needs to be improved to quantify the subsurface inflows to the coastal plain in order to develop the groundwater as a long term resource. This study is intended to enhance the conceptual understanding of the water balance and related recharge processes in this arid environment by developing a regional model of the San Diego region and all watersheds adjacent or draining to the coastal plain, including the Tijuana River basin. This model was used to quantify the various components of the water balance, including semi-quantitative estimates of subsurface groundwater flow to the coastal plain. Other approaches relying on independent data were used to test or constrain the scoping estimates of recharge and runoff, including a reconnaissance-level groundwater model of the San Diego River basin, one of three main rivers draining to the coastal plain. Estimates of subsurface flow delivered to the coastal plain from the river basins ranged from 12.3 to 28.8 million m3 yr-1 from the San Diego River basin for the calibration period (1982-2009) to 48.8 million m3 yr-1 from all major river basins for the entire coastal plain for the long-term period 1940-2009. This range of scoping estimates represents the impact of climatic variability and realistically bounds the likely groundwater availability, while falling well within the variable estimates of regional recharge. However, the scarcity of physical and hydrologic data in this region hinders the exercise to narrow the range and reduce the uncertainty.

  16. Evaluation of military field-water quality

    SciTech Connect

    Selleck, R.E.; Ungun, Z.; Chesler, G.; Diyamandoglu, V.; Marinas, B. . Sanitary Engineering and Environmental Health Research Lab.); Daniels, J.I. )

    1990-05-01

    A comparison is made between the performances of the 600-gph Reverse Osmosis Water Purification Unit (ROWPU) operated in the bypass mode and the Mobile Water Purification Unit (MWPU, frequently referred to as an ERDLATOR because the equipment was developed at the Engineer Research and Development Laboratory at Fort Belvoir, VA.) Generally, the performance of the MWPU is significantly better than the pretreatment units of the ROWPU in terms of removing both turbidity and pathogenic organisms. It is recommended that the practice of bypassing the reverse osmosis (RO) components of the ROWPU be avoided unless it can be demonstrated clearly that the cartridge filters will remove the cysts of infectious organisms effectively and reliably. If the ROWPU must be operated in the bypass mode, it is recommended that the dose of disinfectant used be made equal to that currently employed in the field for untreated raw water. The analytical methods used to determine total dissolved solids (TDS) and residual free chlorine with the new Water-Quality Monitor (WQM) are also reviewed briefly. The limitations of the methods used to calibrate the TDS and free-chlorine probes of the new WQM are discussed. 98 refs., 19 figs., 16 tabs.

  17. Evaluating the impact of SWOT observations§ on the water balance of lakes and wetlands

    NASA Astrophysics Data System (ADS)

    Andreadis, K.; Moller, D.; Rodriguez, E.; Alsdorf, D.

    2012-04-01

    Lakes and wetlands can exert controls on the water and energy fluxes, playing an important role in the local and regional climate. The spatial extent and storage volume of water bodies globally is poorly known, due to lack of measurements over large areas. The planned Surface Water Ocean Topography (SWOT) satellite mission will provide observations of water surface elevation and inundated area globally at an unprecedented spatial resolution. Apart from being used directly, these observations can be used to constrain the water balance simulated hydrologic model over large-scale basins. In this study, the Variable Infiltration Capacity (VIC) macroscale hydrologic model is implemented over the Great Lakes region within an identical twin synthetic experiment. VIC solves an energy and water balance over a gridded domain, and represents lakes and wetlands dynamically as fractional areas of each model grid cell. A baseline simulation of the water and energy balance is designated as "truth", and errors in precipitation, temperature and model parameters are added to simulate a "first-guess" of hydrologic variables of interest. Synthetic SWOT observations are generated from the instrument simulator (developed at JPL) with the anticipated orbital and error characteristics. These "virtual" observations are then assimilated into the "first-guess" model to estimate runoff, evapotranspiration and sensible/latent heat fluxes. The assimilation technique used is the Ensemble Kalman Filter (EnKF), which solves the optimal estimation problem by approximating model and observation errors through a Monte Carlo ensemble approach. The "first-guess" simulation consists of an ensemble of model states that is propagated temporally until a SWOT observation becomes available. The impact of merging the SWOT observations is examined in terms of water and energy fluxes, and the sensitivity of the results to the different observation errors is assessed. The latter can include errors in lake

  18. Major water balance variables Estimation, soil moisture and evaporation time series, using X-band SAR moisture products

    NASA Astrophysics Data System (ADS)

    Gorrab, Azza; Simonneaux, Vincent; Zribi, Mehrez; Saadi, Sameh; Lili-Chabaane, Zohra

    2016-04-01

    continuous Thetaprobe measurements) and plot scale (calibration based on SAR moisture products with very high resolution). Two principal approaches were considered in this research. Firstly, the MHYSAN model was calibrated using a network of seven continous thetaprobe measurements to estimate surface water balance at regional scale. Results gave after calibration an average Nash efficiency which indicates that the MHYSAN model could reproduce correctly SM profiles observed by the major permanent probes at two depths. On the second approach, the MHYSAN model was calibrated for a short period using seven SAR (TerraSAR-X) SM outputs with very high resolution. After considering only three similar texture classes between permanent probes and reference fields (fine, intermediate and coarse groups), validation of the proposed approach was carried out for a long temporal resolution using continuous thetaprobe measurements. These results reveal a good model performance and show that high accurate SM estimations can be achieved after calibrating a bare soil hydrological balance model from SAR moisture products. Overall, the two different approaches reproduce the soil moisture temporal variations well and are in good agreement with modeled MHYSAN SM outputs.

  19. Estimating Evapotrnspiration in a Rice Field Using a Remote-Sensing Based Two Source Energy Balance Model

    NASA Astrophysics Data System (ADS)

    Han, K.; Kustas, W. P.; Anderson, M. C.; Gao, F.; Lee, K.; Hong, S.; Zhang, Y.

    2013-12-01

    Evapotranspiration monitoring of rice, a main cereal and food source of Monsoon Asia, is important not only for sustaining stable grain production and for effective water use through precise water management, but also provides a means for early warning of and response to drought. The remote-sensing based two source energy balance model (TSEB) estimates of evapotranspiration (ET) over a wide variety of land cover types using ground, airborne and satellite imagery and meteorological data without time-consuming and/or expensive field measurements such as measurements of daily decrease of flooding water depth and eddy covariance-based flux tower observations. We, therefore, evaluated the TSEB model at local sites, Icheon and Kimje, with energy flux tower and ground-based thermal-infrared temperature measurement collected over cultivated rice fields and applied the model for estimating ET over rice cropping region encompassing an area 16km x 16km scale in South Korea using Landsat imagery. The TSEB model required modification to the soil heat flux algorithm because rice typically grows in saturated soils and/or standing water for about 75% of the rice growing season. Half-hourly energy flux data, including net radiation, sensible heat, latent heat (corresponding to ET), and soil heat, at two field sites were acquired using eddy-covariance method. The root mean square difference values between predicted and observed latent heat flux ranged between 10% and 25% of the average observed latent heat flux. This is comparable to the measurement uncertainty, suggesting that the TSEB model can provide reliable ET estimation for rice fields. Applying the TSEB model with Landsat imagery over a 16km x 16km domain encompassing the Kimje flux tower site was also performed. Leaf area index for the study area at the Landsat resolution was estimated using MODIS leaf area index products as a reference. Atmospheric correction of the land surface temperature was carried out using MODTRAN

  20. Balancing Water Uptake and Loss through the Coordinated Regulation of Stomatal and Root Development.

    PubMed

    Hepworth, Christopher; Turner, Carla; Landim, Marcela Guimaraes; Cameron, Duncan; Gray, Julie E

    2016-01-01

    Root development is influenced by nutrient and water availabilities. Plants are able to adjust many attributes of their root in response to environmental signals including the size and shape of the primary root, lateral roots and root hairs. Here we investigated the response of roots to changes in the levels of leaf transpiration associated with altered stomatal frequency. We found that plants with high stomatal density and conductance produce a larger rooting area and as a result have enhanced phosphate uptake capacity whereas plants with low stomatal conductance produce a smaller root. Manipulating the growth environment of plants indicated that enhanced root growth is most likely a result of an increased demand for water rather than phosphate. Plants manipulated to have an increase or reduction in root hair growth show a reduction or increase respectively, in stomatal conductance and density. Our results demonstrate that plants can balance their water uptake and loss through coordinated regulation of both stomatal and root development. PMID:27275842

  1. Balancing Water Uptake and Loss through the Coordinated Regulation of Stomatal and Root Development

    PubMed Central

    Hepworth, Christopher; Turner, Carla; Landim, Marcela Guimaraes; Cameron, Duncan; Gray, Julie E.

    2016-01-01

    Root development is influenced by nutrient and water availabilities. Plants are able to adjust many attributes of their root in response to environmental signals including the size and shape of the primary root, lateral roots and root hairs. Here we investigated the response of roots to changes in the levels of leaf transpiration associated with altered stomatal frequency. We found that plants with high stomatal density and conductance produce a larger rooting area and as a result have enhanced phosphate uptake capacity whereas plants with low stomatal conductance produce a smaller root. Manipulating the growth environment of plants indicated that enhanced root growth is most likely a result of an increased demand for water rather than phosphate. Plants manipulated to have an increase or reduction in root hair growth show a reduction or increase respectively, in stomatal conductance and density. Our results demonstrate that plants can balance their water uptake and loss through coordinated regulation of both stomatal and root development. PMID:27275842

  2. Characterization of yield reduction in Ethiopia using a GIS-based crop water balance model

    USGS Publications Warehouse

    Senay, G.B.; Verdin, J.

    2003-01-01

    In many parts of sub-Saharan Africa, subsistence agriculture is characterized by significant fluctuations in yield and production due to variations in moisture availability to staple crops. Widespread drought can lead to crop failures, with associated deterioration in food security. Ground data collection networks are sparse, so methods using geospatial rainfall estimates derived from satellite and gauge observations, where available, have been developed to calculate seasonal crop water balances. Using conventional crop production data for 4 years in Ethiopia (1996-1999), it was found that water-limited and water-unlimited growing regions can be distinguished. Furthermore, maize growing conditions are also indicative of conditions for sorghum. However, another major staple, teff, was found to behave sufficiently differently from maize to warrant studies of its own.

  3. Status of FY 1988 soil-water balance studies on the Hanford site

    SciTech Connect

    Gee, G.W.; Rockhold, M.L.; Downs, J.L.

    1989-02-01

    Natural recharge (i.e., the amount of water from meteorological sources, such as rainfall or snowmelt, that infiltrates through the vadose zone to the groundwater table) at the Hanford Site is a variable quantity because it depends on soil, plant, and climatic factors that vary in time and space over the Site. Water balance data have been collected at selected locations at the Hanford Site for the past 10 years in an attempt to measure or estimate natural recharge for known soil, plant, and climatic conditions. The data collected include precipitation, neutron probe measured water content (storage), and drainage measurements from lysimeters. The lysimeter studies provided the first quantitative estimates of natural recharge at the Hanford Site. 12 refs., 40 figs., 11 tabs.

  4. Holding Water in the Landscape; striking a balance between food production and healthy catchment function

    NASA Astrophysics Data System (ADS)

    Quinn, Paul; Wilkinson, Mark; Stutter, Marc; Adams, Russell

    2015-04-01

    Here it is proposed that ~5 % of the rural landscape could be modified to hold water during storm events. Hence ~95% of land remains for food production, commercial forestry and amenity. This is a catchment scale commitment to sustainably reducing flood and drought risk, improving water quality, biodiversity and thereby climate proofing our catchments. The farmed landscape has intensified and as a result, runoff rates are no longer in balance with the catchment needs, which in turn contributes to floods, droughts and water pollution problems. The loss of infiltration rates, soil water holding capacity and the increase in ditches and drains through intense farming has resulted in a reduction of the overall water holding capacity of the landscape, therefore deeper soil and aquifer recharge rates are lower. However, adequate raw water supply and food production is also vital. Here we consider how ~5% of productive land could be used to physically hold water during and after storms. This is a simple philosophy for water stewardship that could be delivered by farmers and land managers themselves. In this poster we consider a 'treatment train' of mitigation in headwaters by the construction of:- Rural SuDs - by creating swales, bunds and grassy filters; Buffer Strips - (designed to hold water); The Ditch of The Future - by creating the prime location for holding water and recovering lost top soil and finally the better use of Small Headwater Floodplains - by storing flood water, creating wetlands, planting new forest, installing woody debris and new habitats. We present examples of where and how these measures have been installed and show the cost-effectiveness of temporarily holding storm runoff in several case study catchments taken from the UK.

  5. Evaluating the potential of improving residential water balance at building scale.

    PubMed

    Agudelo-Vera, Claudia M; Keesman, Karel J; Mels, Adriaan R; Rijnaarts, Huub H M

    2013-12-15

    Earlier results indicated that, for an average household, self-sufficiency in water supply can be achieved by following the Urban harvest Approach (UHA), in a combination of demand minimization, cascading and multi-sourcing. To achieve these results, it was assumed that all available local resources can be harvested. In reality, however, temporal, spatial and location-bound factors pose limitations to this harvest and, thus, to self-sufficiency. This article investigates potential spatial and temporal limitations to harvest local water resources at building level for the Netherlands, with a focus on indoor demand. Two building types were studied, a free standing house (one four-people household) and a mid-rise apartment flat (28 two-person households). To be able to model yearly water balances, daily patterns considering household occupancy and presence of water using appliances were defined per building type. Three strategies were defined. The strategies include demand minimization, light grey water (LGW) recycling, and rainwater harvesting (multi-sourcing). Recycling and multi-sourcing cater for toilet flushing and laundry machine. Results showed that water saving devices may reduce 30% of the conventional demand. Recycling of LGW can supply 100% of second quality water (DQ2) which represents 36% of the conventional demand or up to 20% of the minimized demand. Rainwater harvesting may supply approximately 80% of the minimized demand in case of the apartment flat and 60% in case of the free standing house. To harvest these potentials, different system specifications, related to the household type, are required. Two constraints to recycle and multi-source were identified, namely i) limitations in the grey water production and available rainfall; and ii) the potential to harvest water as determined by the temporal pattern in water availability, water use, and storage and treatment capacities. PMID:24238880

  6. Water and solute transfer between a prairie wetland and adjacent uplands, 1. Water balance

    NASA Astrophysics Data System (ADS)

    Hayashi, Masaki; van der Kamp, Garth; Rudolph, Dave L.

    1998-06-01

    The hydrology and water quality of lakes and wetlands are controlled by the exchange of water and solutes with adjacent uplands. We studied a small catchment in Saskatchewan, Canada, to evaluate the mechanisms of water and solute transfer between the wetland and the surrounding upland. Detailed measurements of hydrologic processes (precipitation, runoff, evapotranspiration, and subsurface flow) and chloride distribution are combined to improve the estimate of the transfer flux. This paper describes hydrologic processes and Part 2 describes the solute transport processes. Large snowmelt runoff occurs in the catchment, which transfer 30-60% of winter precipitation on the upland into the wetland to form a pond in the center. Snowmelt water and summer precipitation infiltrate under the central pond. Infiltration accounts for 75% of water leaving the central pond and evapotranspiration accounts for 25%. Most of the infiltrated water flows laterally in the shallow subsurface to the wet margin of the pond and further to the upland, where it is consumed by evapotranspiration without recharging deep groundwater. The net recharge rate of the aquifer underlying the catchment is only 1-3 mm year -1. Snowmelt runoff transfers water from the upland to the wetland, and shallow subsurface flow transfers water in the opposite direction. When the two processes are combined, they provide the paths for cyclic transport of solutes.

  7. Evaluating options for balancing the water-electricity nexus in California: part 1--securing water availability.

    PubMed

    Tarroja, Brian; AghaKouchak, Amir; Sobhani, Reza; Feldman, David; Jiang, Sunny; Samuelsen, Scott

    2014-11-01

    The technical potential and effectiveness of different water supply options for securing water availability in a large-scale, interconnected water supply system under historical and climate-change augmented inflow and demand conditions were compared. Part 1 of the study focused on determining the scale of the options required to secure water availability and compared the effectiveness of different options. A spatially and temporally resolved model of California's major surface reservoirs was developed, and its sensitivity to urban water conservation, desalination, and water reuse was examined. Potential capacities of the different options were determined. Under historical (baseline) hydrology conditions, many individual options were found to be capable of securing water availability alone. Under climate change augment conditions, a portfolio approach was necessary. The water savings from many individual options other than desalination were insufficient in the latter, however, relying on seawater desalination alone requires extreme capacity installations which have energy, brine disposal, management, and cost implications. The importance of identifying and utilizing points of leverage in the system for choosing where to deploy different options is also demonstrated. PMID:25022721

  8. Water Reserves Program. An adaptation strategy to balance water in nature

    NASA Astrophysics Data System (ADS)

    Lopez Perez, M.; Barrios, E.; Salinas-Rodriguez, S.; Wickel, B.; Villon, R. A.

    2013-05-01

    Freshwater ecosystems occupy approximately 1% of the earth's surface yet possess about 12% of all known animal species. By virtue of their position in the landscape they connect terrestrial and coastal marine biomes and provide and sustain ecosystem services vital to the health and persistence of human communities. These services include the supply of water for food production, urban and ind ustrial consumption, among others. Over the past century many freshwater ecosystems around the world have been heavily modified or lost due to the alteration of flow regimes (e.g. due to damming, canalization, diversion, over-abstraction). The synergistic impacts of land use change, changes in flows, chemical deterioration, and climate change have left many systems and their species very little room to adjust to change, while future projections indicate a steady increase in water demand for food and energy production and water supply to suit the needs of a growing world population. In Mexico, the focus has been to secure water for human development and maximize economic growth, which has resulted in allocation of water beyond available amounts. As a consequence episodic water scarcity severely constrains freshwater ecosystems and the services they provide. Climatic change and variability are presenting serious challenges to a country that already is experiencing serious strain on its water resources. However, freshwater ecosystems are recognized by law as legitimate user of water, and mandate a flow allocation for the environment ("water reserve" or "environmental flows"). Based on this legal provision the Mexican government through the National Water Commission (Conagua), with support of the Alliance WWF - Fundación Gonzalo Río Arronte, and the Interamerican Development Bank, has launched a national program to identify and implement "water reserves": basins where environmental flows will be secured and allocated and where the flow regime is then protected before over

  9. Characterizing the role of hydrological processes on lake water balances in the Old Crow Flats, Yukon Territory, Canada, using water isotope tracers

    NASA Astrophysics Data System (ADS)

    Turner, Kevin W.; Wolfe, Brent B.; Edwards, Thomas W. D.

    2010-05-01

    SummaryWe employ water isotope tracers to assess hydrological processes controlling lake water balances in the Old Crow Flats (OCF) landscape, northern Yukon Territory, Canada. Fifty-six lakes were sampled in June and July 2007 and 26 of these were re-sampled in September 2007. Based on patterns of isotopic evolution in δ18O- δ2H space, calculations of input water compositions ( δI) and evaporation-to-inflow ( E/ I) ratios, and field observations we identify snowmelt-dominated, rainfall-dominated, groundwater-influenced, evaporation-dominated and drained lake types, which represent the dominant hydrological process influencing the lake water balance. These results highlight the diversity in lake water balance conditions in the OCF, which are strongly associated with landscape characteristics. Snowmelt-dominated lakes are located where more dense vegetation cover entraps snow transported by prevailing northeasterly winds. Rainfall-dominated lakes occupy areas of sparse tundra vegetation cover where less snow accumulates. Groundwater-influenced oxbow lakes are located along the floodplain of higher-order river and creek channels and receive input throughout the ice-free season from snowmelt-recharged channel fens and sub-surface flow. Only one basin became evaporation-dominated during the 2007 open-water season probably because extremely high precipitation during the preceding late summer, late winter and early spring offset vapour loss. However, rainfall-dominated lakes appear to be more susceptible to evaporative drawdown than snowmelt-dominated and groundwater-influenced lakes, and many would likely evolve to evaporation-dominated during drier summers. Drained lakes are commonly observed throughout the landscape and in most cases likely result from elevated water levels and channel erosion between waterbodies. Unusually high amounts of snowmelt and/or rainfall triggered the drainage of two lakes in early June 2007 in which overflow led to rapid erosion of

  10. Climate impacts on water balance of a shallow steppe lake in Eastern Austria (Lake Neusiedl)

    NASA Astrophysics Data System (ADS)

    Soja, Gerhard; Züger, Johann; Knoflacher, Markus; Kinner, Paul; Soja, Anna-Maria

    2013-02-01

    SummaryLake Neusiedl, the largest lake in Austria, is especially sensitive to climate variations due to its extreme shallowness and a small catchment area. Historical records indicate that large variations of the lake area have occurred naturally (0% to >150% of present) but contemporary touristic uses of the lake require a largely constant water level. This dependence increases the regional economic vulnerability. Water balance of the lake as influenced by weather conditions was studied in detail. 79% of water input was due to precipitation, whereas more than 90% of water output was caused by evapotranspiration. Long-term observation of annual and seasonal precipitation sums, starting in 1865, revealed a slow downward trend of 15 years moving averages by 6 ± 1 mm/decade, masked by large interannual variations of the original data (s.d.: ±120 mm). Multidecadal oscillation indices (AMO, NAO, MOI) were tested against patterns of precipitation, air temperature and hydrological parameters of Lake Neusiedl. The clearest relation was observed between air temperature and North Atlantic oscillation index (p < 0.0001). Water level and volume of Lake Neusiedl are very sensitive to precipitation changes with after effects of individual years lasting up to 2 years. Summer precipitation is more important for lake water amount than the other seasons. The major surface water input to Lake Neusiedl is coming from River Wulka. Its annual discharge (15 years moving averages) showed a variable, moderately decreasing trend for the period 1961-2010 by -1.2 ± 0.6 × 106 m3/decade. Waste water treatment plants contributed up to 68% of monthly flow of River Wulka into the lake. Precipitation of the current and the previous year, and in some months also temperature influenced Wulka's flow significantly. Evaporative losses from the lake and its reed belt were shown to increase over the last 33 years (+48 ± 11 mm/decade); as main drivers decreasing relative air humidity and increasing

  11. New data on the bottom topography, recent sedimentation and water balance of Cerro Prieto dam, Mexico

    NASA Astrophysics Data System (ADS)

    Yutsis, Vsevolod; Levchenko, Oleg; Lowag, Jens; Krivosheya, Konstantin; de León Gómez, Héctor; Kotsarenko, Anatolyi

    2010-05-01

    Cerro Prieto Dam, a small water reservoir in the NE Mexico, is characterized by very high velocity of recent sedimentation, high sub-bottom seepage and erosion, and as a result, nonlinear water balance. These phenomenons never were studied since construction of the dam in the beginning of 1980th. So the goal of our work was to investigate the bottom topography and also sub-bottom near surface structure using the parametric acoustical effect. High-resolution sub-bottom profiling, using the Innomar SES-2000 compact echosounder, was carried out in Cerro Prieto Dam during February-April of 2008. The survey was conducted onboard of a small motor boat. The SES transducer was mounted on the front side of the boat using light metal pipe, and all electronic equipment was installed on the deck. Accurate positioning of the boat was reached by GPS. Average speed was 8-10 km/h. Innomar's software tool ISE was provides near real-time post-processing of the collected SES data and operation procedure could be corrected on-line. Acoustic signal ensured vertical resolution of 10-15 cm at acceptable penetration up to 15 m. Bathymetry map was compiled assuming average sound velocity of 1450 m/s. The irregular bottom topography of Cerro Prieto dam was discovered. The present elevation of the water surface is about 181 m above see level, and the lake depth varies from 1-2 to 28 m. The SES records show a distinct bottom layer of recent sediments by 0.5 - 4 m thickness which follows reservoir floor topography. Very specific acoustic anomalies, which seem to be related with gas sediments, are observed. The integrated SES, gravity, magnetic and geoelectrical data interpretation allows assuming a series of the superficial fractures focused in a NW direction, perpendicular (NE-SW) to the general deep fault zone. Hydrological balance for the Cerro Prieto water reservoir has been analyzed for last two decades. There are three types of water level fluctuations on the Cerro Prieto dam: long

  12. Balancing Storage - some very different management approaches in a water scarce Developing Country.

    NASA Astrophysics Data System (ADS)

    Tollow, Anthony John

    2010-05-01

    Balancing storage may be found in many different forms in South Africa. The first feature is often a large reservoir fairly high up the catchment, where losses are less, or even in a neighbouring catchment. The objective is to catch surplus water for later use. Alternatives include both within basin and interbasin transfers, either pumped over a catchment divide, or fed under gravity through a tunnel. Again there may be a reservoir at the start of the transfer scheme. This may be a large reservoir or may be a balancing storage reservoir. Transfers are required to make up for a deficiency of water in the demand area of the receiving catchment. The deficiency may be intermittent or continuous. Nevertheless, whatever the nature of the deficiency, it is important not to incur losses. The water will be more expensive than if it were possible to obtain it locally from within the demand area. When undertaking river regulation, one major concern is seeing expensive water flowing out to sea. Several different schemes are contrasted. One has been developed to run almost completely by gravity, others use the topography where possible with the aid of canals, gravity tunnels and pipelines. However, in some circumstances expensive electricity is required to pump the water to be transferred. Nowadays with the ever increasing cost of electricity some way is required of reducing the cost. The usual approach is to use "off peak" electricity but river release flows do not always cooperate so there is a further risk of loss, due to the induced "peaks and troughs" in the river hydrograph as the pumps are switched on and off. Balancing storage becomes even more important in this case to act as a smoothing mechanism. Sometimes the storage may take the form of an on stream reservoir, at others a suitable site besides the river may be developed. This latter has another advantage in allowing the system to avoid abstracting the inevitably poor quality of water at the start of the first

  13. A PCSWMM/GIS-based water balance model for the Reesor Creek watershed

    NASA Astrophysics Data System (ADS)

    Smith, D.; Li, J.; Banting, D.

    2005-09-01

    This paper presents the results of a study of a watershed experiencing the pressures of land-use change resulting from urban development. The study was undertaken to facilitate an understanding of the water balance of the watershed by developing and implementing watershed procedures that are to be addressed in a watershed plan. There were three components to the research: firstly, observation of the effects of spatially distributed rainfall measurements and their effect on modelling were assessed. Secondly, the model was then calibrated by observing how differing techniques can discretize both the landscape (e.g. land-use and soil type) and incoming precipitation. Finally, a modelling methodology was developed to integrate a Geographic Information System and a hydrologic model (e.g. Storm Water Management Model) in a water balance analysis on a watershed basis. Results show that, under certain conditions, kriging spatially distributed rainfall values can help predict rainfall at ungauged (virtual) sites. Discretization of a watershed was found to affect the differences between measured and generated runoff volumes; however, this can be refined with calibration. It was seen that a strong correlation between measured and predicted rainfall values did not always guarantee a strong relationship between measured and generated runoff Recommendations include the use of a longer time series of rainfall, streamflow and predicted rainfall to observe temporal variations, and the need to assess the differences in modelled rainfall values generated by various surface interpolation methods (e.g. Inverse Distance Weighting and other kriging options) currently available in GIS packages.

  14. Do changes in global biomass have a detectable impact on the water balance?

    NASA Astrophysics Data System (ADS)

    Larsen, J.; Jarihani, B.

    2015-12-01

    Recent studies have shown a wide range of decadal scale global biomass changes, with many boreal forests increasing in biomass, and tropical areas continuing to decline. A critical question that follows from this is whether or not these changes are having a measurable impact on the water balance. Here, we use a Budyko approach in combination with global datasets of precipitation (P), potential evaporation (PET), discharge (Q), and actual evapotranspiration (ET) to assess whether detectable trends in surface runoff exist, and whether this is consistent with the availability predicted by the Budyko water and energy balance. These trends are further complicated by the scaling of hydrological change with climate (PET/P), and the wide variation in climate trends, particularly P. Nonetheless, the detection of hydrological responses to vegetation change at the global scale is a large gap in our understanding of human impacts on the hydrological cycle, and this work seeks to clarify when and where such impacts may be present. This has important implications for future water resource availability, since biomass (or land cover) changes are not considered to the same extent as the potential impact of greenhouse gas emissions, and yet vegetation changes may have a far more direct and influential role in the hydrological cycle.

  15. Experimental and numerical investigations of soil water balance at the hinterland of the Badain Jaran Desert for groundwater recharge estimation

    NASA Astrophysics Data System (ADS)

    Hou, Lizhu; Wang, Xu-Sheng; Hu, Bill X.; Shang, Jie; Wan, Li

    2016-09-01

    Quantification of groundwater recharge from precipitation in the huge sand dunes is an issue in accounting for regional water balance in the Badain Jaran Desert (BJD) where about 100 lakes exist between dunes. In this study, field observations were conducted on a sand dune near a large saline lake in the BJD to investigate soil water movement through a thick vadose zone for groundwater estimation. The hydraulic properties of the soils at the site were determined using in situ experiments and laboratory measurements. A HYDRUS-1D model was built up for simulating the coupling processes of vertical water-vapor movement and heat transport in the desert soil. The model was well calibrated and validated using the site measurements of the soil water and temperature at various depths. Then, the model was applied to simulate the vertical flow across a 3-m-depth soil during a 53-year period under variable climate conditions. The simulated flow rate at the depth is an approximate estimation of groundwater recharge from the precipitation in the desert. It was found that the annual groundwater recharge would be 11-30 mm during 1983-2012, while the annual precipitation varied from 68 to 172 mm in the same period. The recharge rates are significantly higher than those estimated from the previous studies using chemical information. The modeling results highlight the role of the local precipitation as an essential source of groundwater in the BJD.

  16. Electropumping of water with rotating electric fields

    NASA Astrophysics Data System (ADS)

    De Luca, Sergio; Todd, B. D.; Hansen, J. S.; Daivis, Peter J.

    2013-04-01

    Pumping of fluids confined to nanometer dimension spaces is a technically challenging yet vitally important technological application with far reaching consequences for lab-on-a-chip devices, biomimetic nanoscale reactors, nanoscale filtration devices and the like. All current pumping mechanisms require some sort of direct intrusion into the nanofluidic system, and involve mechanical or electronic components. In this paper, we present the first nonequilibrium molecular dynamics results to demonstrate that non-intrusive electropumping of liquid water on the nanoscale can be performed by subtly exploiting the coupling of spin angular momentum to linear streaming momentum. A spatially uniform rotating electric field is applied to water molecules, which couples to their permanent electric dipole moments. The resulting molecular rotational momentum is converted into linear streaming momentum of the fluid. By selectively tuning the degree of hydrophobicity of the solid walls one can generate a net unidirectional flow. Our results for the linear streaming and angular velocities of the confined water are in general agreement with the extended hydrodynamical theory for this process, though also suggest refinements to the theory are required. These numerical experiments confirm that this new concept for pumping of polar nanofluids can be employed under laboratory conditions, opening up significant new technological possibilities.

  17. Century-scale variability in global annual runoff examined using a water balance model

    USGS Publications Warehouse

    McCabe, G.J.; Wolock, D.M.

    2011-01-01

    A monthly water balance model (WB model) is used with CRUTS2.1 monthly temperature and precipitation data to generate time series of monthly runoff for all land areas of the globe for the period 1905 through 2002. Even though annual precipitation accounts for most of the temporal and spatial variability in annual runoff, increases in temperature have had an increasingly negative effect on annual runoff after 1980. Although the effects of increasing temperature on runoff became more apparent after 1980, the relative magnitude of these effects are small compared to the effects of precipitation on global runoff. ?? 2010 Royal Meteorological Society.

  18. On the treatment of evapotranspiration, soil moisture accounting, and aquifer recharge in monthly water balance models.

    USGS Publications Warehouse

    Alley, W.M.

    1984-01-01

    Several two- to six-parameter regional water balance models are examined by using 50-year records of monthly streamflow at 10 sites in New Jersey. These models include variants of the Thornthwaite-Mather model, the Palmer model, and the more recent Thomas abcd model. Prediction errors are relatively similar among the models. However, simulated values of state variables such as soil moisture storage differ substantially among the models, and fitted parameter values for different models sometimes indicated an entirely different type of basin response to precipitation.-from Author

  19. Simulated changes in the atmospheric water balance over South Asia in the eight IPCC AR4 coupled climate models

    NASA Astrophysics Data System (ADS)

    Prasanna, Venkatraman; Yasunari, Tetsuzo

    2011-05-01

    This paper evaluates the performance of eight state-of-art IPCC-AR4 coupled atmosphere-ocean general circulation models in their representation of regional characteristics of atmospheric water balance over South Asia. The results presented here are the regional climate change scenarios of atmospheric water balance components, precipitation, moisture convergence and evaporation ( P, C and E) up to the end of the twenty-second century based on IPCC AR4 modelling experiments conducted for (A1B) future greenhouse gas emission scenario. The AOGCMs, despite their relatively coarse resolution, have shown a reasonable skill in depicting the hydrological cycle over the South Asian region. However, considerable biases do exist with reference to the observed atmospheric water balance and also inter-model differences. The monsoon rainfall and atmospheric water balance changes under A1B scenario are discussed in detail. Spatial patterns of rainfall change projections indicate maximum increase over northwest India in most of the models, but changes in the atmospheric water balance are generally widespread over South Asia. While the scenarios presented in this study are indicative of the expected range of rainfall and water balance changes, it must be noted that the quantitative estimates still have large uncertainties associated with them.

  20. The Thermal Circulation on Kilimanjaro, Tanzania and its Relevance to Summit Ice-Field Mass Balance.

    NASA Astrophysics Data System (ADS)

    Pepin, N. C.; Duane, W. J.

    2008-12-01

    It is well known that mountains create their own climates. On Kilimanjaro, which is the tallest free standing mountain in Africa, the intense tropical sunlight generates a strong diurnal mountain circulation which transports moisture up the mountain during the day and back downslope at night. This process has strong consequences for development of cloud cover, precipitation, and hence ice-field mass balance on the summit crater. We compare surface climate (temperature, moisture and wind) measured at ten elevations on Kilimanjaro, with equivalent observations in the free atmosphere from NCEP/NCAR reanalysis data for September 2004 to July 2008. There are no simple temporal trends over this period in either surface of free- air data. Correlations between daily surface and free air temperatures are greatest below 2500 metres, meaning that synoptic (inter-diurnal) variability is the major control here. In contrast, temperatures and moisture on the higher slopes above treeline (about 3000 m) are strongly decoupled from the free atmosphere, showing intense heating/cooling by day/night (more than 5°C). The sparsely vegetated upper slopes are the focus for the most intense heating and upslope winds develop by mid-morning. The forest on the lower slopes acts as a moisture source, with large vapour pressure excesses reported (5 mb) which move upslope reaching the crater in the afternoon before subsiding downslope at night. The montane thermal circulation is more effective at upslope moisture transport during January as compared with July. Fluctuations in upper air flow strength and direction (at 500 mb) surprisingly have limited influence on the strength of surface heating and upslope moisture advection. This finding suggests that local changes in surface characteristics such as deforestation could have a strong influence on the mountain climate and the summit ice fields on Kilimanjaro, and make mass-balance somewhat divorced from larger-scale advective changes associated

  1. Impact of Soil Moisture Conditions on Interannual Variability of the Water Balance over the North American Monsoon Region

    NASA Astrophysics Data System (ADS)

    Xu, J.; Small, E.; Lakshmi, V.

    2001-12-01

    In this study, the effects of soil moisture conditions on interannual variability of the water balance over the North American monsoon (NAM) region was investigated using NCAR's MM5/OSU model. Observations and modeling studies suggest that a positive soil moisture-rainfall feedback may be important in magnifying and prolonging hydroclimatic anomalies in a variety of regions. Our preliminary modeling experiments show that the soil moisture-rainfall feedback is strong in the North American Monsoon System (NAMS) region and may contribute to variability of summertime precipitation in this area. However, this result is based on sensitivity experiments using extreme forcing - soil moisture was held at field capacity or wilting point throughout season long simulations. Here we use the MM5 model linked to the OSU land surface scheme to assess the strength of soil moisture-rainfall feedbacks in the NAMS region that result from realistic soil moisture forcing. Simulations are driven by NCEP reanalysis. The horizontal resolution of the finest grid is 30 km. Three member ensemble experiments begin on June 1 and end on October 1. First, we use the coupled MM5/OSU model to simulate NAMS climate and soil moisture in wet (1999) and dry (2000) monsoon seasons. Second, we repeat these two experiments but constrain the precipitation rate in July over the entire NAM region so that it approximates the mean state. This is accomplished by scaling the simulated precipitation at each point so that it is equal to mean observed precipitation at that location. Third, we repeat the 1999 and 2000 experiments but constrain the soil moisture field in July to the climatological mean value from the NCEP reanalysis. Both types of sensitivity experiments preserve the temporal variability of sea surface temperature (SST) in the surrounding oceans. We compare the atmosphere and land surface state in the control and sensitivity experiments. This isolates the effects of soil moisture anomalies on the

  2. What balance do countries exhibit between the central human resources: water, energy and food

    NASA Astrophysics Data System (ADS)

    Kossak, Julian; Reusser, Dominik E.; Kropp, Jürgen P.

    2013-04-01

    Sufficient water, food and energy is a precondition for human activities. The water, energy and food nexus states that to some extend, these resources can replace each another: land can be used to produce food or energy crops; water can be used as direct water supply, to produce energy or for irrigation; and energy supports water treatment and agricultural yield. We present an overview of the major components of the trade-off together with a set of indicators and data sources to assess these components. The different indicators of the trade-off are summarized and plotted in a novel way on a triangle, which we discuss in view of the resource availability of different countries. Comparing different countries in view of their balance between water, food and energy will inform the discussion about the transition towards more sustainable societies and highlighting alternative strategies for development. This is important in view of possible synergies between the different sectors and as a tool for better coordinated governance approaches.

  3. Impact of soil vertical water movement on the energy balance of different land surfaces.

    PubMed

    Gao, Zhiqiu; Chen, George Tai-Jen; Hu, Yanbing

    2007-08-01

    The soil heat flux determination method proposed by Gao (Boundary-Layer Meteorol 114:165-178, 2005) is discussed for (1) dry surfaces, (2) bare soil or sparse short-grass lands, and (3) dense-grass surfaces or forest. Our analysis shows that, when neglecting the contribution of soil vertical water movement to soil heat flux, the energy components measured independently will (1) still achieve balance over dry surfaces, and (2) be significantly in imbalance over bare soil or sparse short-grass lands. The mean of bare ground evaporation modeled by SiB2 is 1.58 x 10(-5) m(3) s(-1) m(-2), and the mean of soil water flux obtained by the method of Gao is 1.22 x 10(-5) m(3) s(-1) m(-2) for the Naqu site in the summer of 1998. Comparison of the bare ground evaporation with the mean of soil water flux shows a difference, the causes of which are investigated. Physically, the bare ground evaporation is equal to the sum of soil water flux and water content change in the soil surface layer. Because the bare ground evaporation is very limited for the dense-grass surfaces or forest, our analysis implies that the energy imbalance encountered over the dense-grass or forest is not caused by the fact that previous researchers neglected soil water movements in their energy budget analyses. PMID:17429698

  4. Investigating onychophoran gas exchange and water balance as a means to inform current controversies in arthropod physiology.

    PubMed

    Clusella-Trullas, Susana; Chown, Steven L

    2008-10-01

    Several controversies currently dominate the fields of arthropod metabolic rate, gas exchange and water balance, including the extent to which modulation of gas exchange reduces water loss, the origins of discontinuous gas exchange, the relationship between metabolic rate and life-history strategies, and the causes of Palaeozoic gigantism. In all of these areas, repeated calls have been made for the investigation of groups that might most inform the debates, especially of taxa in key phylogenetic positions. Here we respond to this call by investigating metabolic rate, respiratory water loss and critical oxygen partial pressure (Pc) in the onychophoran Peripatopsis capensis, a member of a group basal to the arthropods, and by synthesizing the available data on the Onychophora. The rate of carbon dioxide release (VCO2) at 20 degrees C in P. capensis is 0.043 ml CO2 h(-1), in keeping with other onychophoran species; suggesting that low metabolic rates in some arthropod groups are derived. Continuous gas exchange suggests that more complex gas exchange patterns are also derived. Total water loss in P. capensis is 57 mg H2O h(-1) at 20 degrees C, similar to modern estimates for another onychophoran species. High relative respiratory water loss rates ( approximately 34%; estimated using a regression technique) suggest that the basal condition in arthropods may be a high respiratory water loss rate. Relatively high Pc values (5-10% O2) suggest that substantial safety margins in insects are also a derived condition. Curling behaviour in P. capensis appears to be a strategy to lower energetic costs when resting, and the concomitant depression of water loss is a proximate consequence of this behaviour. PMID:18805813

  5. Climate change impact on the annual water balance in the northwest Florida coastal

    NASA Astrophysics Data System (ADS)

    Alizad, K.; Wang, D.; Alimohammadi, N.; Hagen, S. C.

    2012-12-01

    As the largest tributary to the Apalachicola River, the Chipola River originates in southern Alabama, flows through Florida Panhandle and ended to Gulf of Mexico. The Chipola watershed is located in an intermediate climate environment with aridity index around one. Watershed provides habitat for a number of threatened and endangered animal and plant species. However, climate change affects hydrologic cycle of Chipola River watershed at various temporal and spatial scales. Studying the effects of climate variations is of great importance for water and environmental management purposes in this catchment. This research is mainly focuses on assessing climate change impact on the partitioning pattern of rainfall from mean annual to inter-annual and to seasonal scales. At the mean annual scale, rainfall is partitioned into runoff and evaporation assuming negligible water storage changes. Mean annual runoff is controlled by both mean annual precipitation and potential evaporation. Changes in long term mean runoff caused by variations of long term mean precipitation and potential evaporation will be evaluated based on Budyko hypothesis. At the annual scale, rainfall is partitioned into runoff, evaporation, and storage change. Inter-annual variability of runoff and evaporation are mainly affected by the changes of mean annual climate variables as well as their inter-annual variability. In order to model and evaluate each component of water balance at the annual scale, parsimonious but reliable models, are developed. Budyko hypothesis on the existing balance between available water and energy supply is reconsidered and redefined for the sub-annual time scale and reconstructed accordingly in order to accurately model seasonal hydrologic balance of the catchment. Models are built in the seasonal time frame with a focus on the role of storage change in water cycle. Then for Chipola catchment, models are parameterized based on a sufficient time span of historical data and the

  6. Analysis of plant available water in the context of climate change using Thornthwaite type monthly water balance model

    NASA Astrophysics Data System (ADS)

    Herceg, Andras; Gribovszki, Zoltan; Kalicz, Peter

    2016-04-01

    The hydrological impact of climate change can be dramatic. The primary objective of this paper was to analyze plant available water in the context of climate change using Thornthwaite type monthly water balance calibrated by remote sensing based ET maps. The calibrated model was used for projection on the basis of 4 climate model datasets. The 3 periods of projection were: 2010-2040, 2040-2070, and 2070-2100. The benefit of this method is its robust build up, which can be applied if temperature and precipitation time series are accessible. The key parameter is the water storage capacity of the soil (SOILMAX), which can be calibrated using the actual available evapotranspiration data. If the soil's physical properties are available, the maximal rooting depth is also projectable. Plant available water was evaluated for future scenarios focusing water stress periods. For testing the model, a dataset of an agricultural parcel next to Mosonmagyaróvár and a dataset of a small forest covered catchment next to Sopron were successfully used. Each of the models projected slightly ascending evapotranspiration values (+7 percent), but strongly decreasing soil moisture values (-15 percent) for the 21st century. The soil moisture minimum values (generally appeared at the end of the summer) reduced more than 50 percent which indicate almost critical water stress for vegetation. This research has been supported by Agroclimate.2 VKSZ_12-1-2013-0034 project.

  7. Water use efficiency and crop water balance of rainfed wheat in a semi-arid environment: sensitivity of future changes to projected climate changes and soil type

    NASA Astrophysics Data System (ADS)

    Yang, Yanmin; Liu, De Li; Anwar, Muhuddin Rajin; O'Leary, Garry; Macadam, Ian; Yang, Yonghui

    2016-02-01

    Wheat production is expected to be affected by climate change through changing components of the crop water balance such as rainfall, evapotranspiration (ET), runoff and drainage. We used the Agricultural Production Systems Simulator (APSIM)-wheat model to simulate the potential impact of climate change on field water balance, ET and water use efficiency (WUE) under the SRES A2 emissions scenario. We ran APSIM with daily climate data statistically downscaled from 18 Global Circulation Models (GCMs). Twelve soil types of varying plant available water holding capacity (PAWC) at six sites across semi-arid southeastern Australia were considered. Biases in the GCM-simulated climate data were bias-corrected against observations for the 1961-1999 baseline period. However, biases in the APSIM output data relative to APSIM simulations forced with climate observations remained. A secondary bias correction was therefore performed on the APSIM outputs. Bias-corrected APSIM outputs for a future period (2021-2040) were compared with APSIM outputs generated using observations for the baseline period to obtain future changes. The results show that effective rainfall was decreased over all sites due to decreased growing season rainfall. ET was decreased through reduced soil evaporation and crop transpiration. There were no significant changes in runoff at any site. The variation in deep drainage between sites was much greater than for runoff, ranging from less than a few millimetres at the drier sites to over 100 mm at the wetter. However, in general, the averaged drainage over different soil types were not significantly different between the baseline (1961-1999) and future period of 2021-2040 ( P > 0.05). For the wetter sites, the variations in the future changes in drainage and runoff between the 18 GCMs were larger than those of the drier sites. At the dry sites, the variation in drainage decreased as PAWC increased. Overall, water use efficiency based on transpiration (WUE

  8. Water-Balance Model of a Wetland on the Fort Berthold Reservation, North Dakota

    USGS Publications Warehouse

    Vining, Kevin C.

    2007-01-01

    A numerical water-balance model was developed to simulate the responses of a wetland on the Fort Berthold Reservation, North Dakota, to historical and possible extreme hydrological inputs and to changes in hydrological inputs that might occur if a proposed refinery is built on the reservation. Results from model simulations indicated that the study wetland would likely contain water during most historical and extreme-precipitation events with the addition of maximum potential discharges of 0.6 acre-foot per day from proposed refinery holding ponds. Extended periods with little precipitation and above-normal temperatures may result in the wetland becoming nearly dry, especially if potential holding-pond discharges are near zero. Daily simulations based on the historical-enhanced climate data set for May and June 2005, which included holding-pond discharges of 0.6 acre-foot per day, indicated that the study-wetland maximum simulated water volume was about 16.2 acre-feet and the maximum simulated water level was about 1.2 feet at the outlet culvert. Daily simulations based on the extreme summer data set, created to represent an extreme event with excessive June precipitation and holding-pond discharges of 0.6 acre-foot per day, indicated that the study-wetland maximum simulated water volume was about 38.6 acre-feet and the maximum simulated water level was about 2.6 feet at the outlet culvert. A simulation performed using the extreme winter climate data set and an outlet culvert blocked with snow and ice resulted in the greatest simulated wetland water volume of about 132 acre-feet and the greatest simulated water level, which would have been about 6.2 feet at the outlet culvert, but water was not likely to overflow an adjacent highway.

  9. Evapotranspiration and water balance of an anthropogenic coastal desert wetland: responses to fire, inflows and salinities

    USGS Publications Warehouse

    Glenn, Edward P.; Mexicano, Lourdes; Garcia-Hernandez, Jaqueline; Nagler, Pamela L.; Gomez-Sapiens, Martha M.; Tang, Dawei; Lomeli, Marcelo A.; Ramirez-Hernandez, Jorge; Zamora-Arroyo, Francisco

    2013-01-01

    Evapotranspiration (ET) and other water balance components were estimated for Cienega de Santa Clara, an anthropogenic brackish wetland in the delta of the Colorado River in Mexico. The marsh is in the Biosphere Reserve of the Upper Gulf of California and Delta of the Colorado River, and supports a high abundance and diversity of wildlife. Over 95% of its water supply originates as agricultural drain water from the USA, sent for disposal in Mexico. This study was conducted from 2009 to 2011, before, during and after a trial run of the Yuma Desalting Plant in the USA, which will divert water from the wetland and replace it with brine from the desalting operation. The goal was to estimate the main components in the water budget to be used in creating management scenarios for this marsh. We used a remote sensing algorithm to estimate ET from meteorological data and Enhanced Vegetation Index values from the Moderate Resolution Imaging Spectrometer (MODIS) sensors on the Terra satellite. ET estimates from the MODIS method were then compared to results from a mass balance of water and salt inflows and outflows over the study period. By both methods, mean annual ET estimates ranged from 2.6 to 3.0 mm d−1, or 50 to 60% of reference ET (ETo). Water entered at a mean salinity of 2.6 g L−1 TDS and mean salinity in the wetland was 3.73 g L−1 TDS over the 33 month study period. Over an annual cycle, 54% of inflows supported ET while the rest exited the marsh as outflows; however, in winter when ET was low, up to 90% of the inflows exited the marsh. An analysis of ET estimates over the years 2000–2011 showed that annual ET was proportional to the volume of inflows, but was also markedly stimulated by fires. Spring fires in 2006 and 2011 burned off accumulated thatch, resulting in vigorous growth of new leaves and a 30% increase in peak summer ET compared to non-fire years. Following fires, peak summer ET estimates were equal to ETo, while in non-fire years peak ET was

  10. Strengthening of the hydrological cycle in future scenarios: atmospheric energy and water balance perspective

    NASA Astrophysics Data System (ADS)

    Alessandri, A.; Fogli, P. G.; Vichi, M.; Zeng, N.

    2012-11-01

    Future climate scenarios experiencing global warming are expected to strengthen the hydrological cycle during the 21st century (21C). We analyze the strengthening of the global-scale increase in precipitation from the perspective of changes in whole atmospheric water and energy balances. By combining energy and water equations for the whole atmosphere, we obtain constraints for the changes in surface fluxes and partitioning at the surface between sensible and latent components. We investigate the differences in the strengthening of the hydrological cycle in two centennial simulations performed with an Earth system model forced with specified atmospheric concentration pathways. Alongside the Special Report on Emissions Scenario (SRES) A1B, which is a medium-high non-mitigation scenario, we consider a new aggressive-mitigation scenario (E1) with reduced fossil fuel use for energy production aimed at stabilizing global warming below 2 K. Our results show that the mitigation scenario effectively constrains the global warming with a stabilization below 2 K with respect to the 1950-2000 historical period. On the other hand, the E1 precipitation does not follow the temperature field toward a stabilization path but continues to increase over the mitigation period. Quite unexpectedly, the mitigation scenario is shown to strengthen the hydrological cycle even more than SRES A1B till around 2070. We show that this is mostly a consequence of the larger increase in the negative radiative imbalance of atmosphere in E1 compared to A1B. This appears to be primarily related to decreased sulfate aerosol concentration in E1, which considerably reduces atmospheric absorption of solar radiation compared to A1B. The last decades of the 21C show a marked increase in global precipitation in A1B compared to E1, despite the fact that the two scenarios display almost the same overall increase of radiative imbalance with respect to the 20th century. Our results show that radiative cooling is

  11. Does deficit irrigation of field crops increase water use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deficit irrigation is often proposed as a method to stretch limited irrigation water supply and increase water use efficiency. A field study of field crops in the high plains shows that water use efficiency, in terms of irrigation water applied, often increases with deficit irrigation. However, in t...

  12. Influence of the Aral Sea negative water balance on its seasonal circulation and ventilation patterns: use of a 3d hydrodynamic model.

    NASA Astrophysics Data System (ADS)

    Sirjacobs, D.; Grégoire, M.; Delhez, E.; Nihoul, J.

    2003-04-01

    Within the context of the EU INCO-COPERNICUS program "Desertification in the Aral Sea Region: A study of the Natural and Anthropogenic Impacts" (Contract IAC2-CT-2000-10023), a large-scale 3D hydrodynamic model was adapted to address specifically the macroscale processes affecting the Aral Sea water circulation and ventilation. The particular goal of this research is to simulate the effect of lasting negative water balance on the 3D seasonal circulation, temperature, salinity and water-mixing fields of the Aral Sea. The original Aral Sea seasonal hydrodynamism is simulated with the average seasonal forcings corresponding to the period from 1956 to 1960. This first investigation concerns a period of relative stability of the water balance, before the beginning of the drying process. The consequences of the drying process on the hydrodynamic of the Sea will be studied by comparing this first results with the simulation representing the average situation for the years 1981 to 1985, a very low river flow period. For both simulation periods, the forcing considered are the seasonal fluctuations of wind fields, precipitation, evaporation, river discharge and salinity, cloud cover, air temperature and humidity. The meteorological forcings were adapted to the common optimum one-month temporal resolution of the available data sets. Monthly mean kinetic energy flux and surface tensions were calculated from daily ECMWF wind data. Monthly in situ precipitation, surface air temperature and humidity fields were interpolated from data obtained from the Russian Hydrological and Meteorological Institute. Monthly water discharge and average salinity of the river water were considered for both Amu Darya and Syr Darya river over each simulation periods. The water mass conservation routines allowed the simulation of a changing coastline by taking into account local drying and flooding events of particular grid points. Preliminary barotropic runs were realised (for the 1951

  13. A review of the Budyko water balance framework: moving from a rich history to a bright future

    NASA Astrophysics Data System (ADS)

    Berghuijs, Wouter; Greve, Peter

    2015-04-01

    The Budyko framework is a widely used representation of the land water balance that describes the mean-annual partitioning of precipitation into streamflow and evaporation, as a function of the ratio of the atmospheric water supply (precipitation) to water demand (potential evaporation). The striking simplicity of this demand-supply relationship has served as a catalyst for understanding and prediction of water balance behavior. Here we provide an overview of progress made with the Budyko framework, from its beginnings to the extensive present day use. The framework's simplicity, timelessness and versatility make it a powerful scientific and engineering tool that provides a valuable contrast and addition to the plethora of highly parameterized models used to describe water balance behavior. However, we identify 10 key questions that need to be addressed to ensure a bright future for the framework where it can maintain spot on the forefront of hydrologic science and applications

  14. Application of a spatially distributed water balance model for assessing surface water and groundwater resources in the Geba basin, Tigray, Ethiopia

    NASA Astrophysics Data System (ADS)

    Gebreyohannes, Tesfamichael; De Smedt, Florimond; Walraevens, Kristine; Gebresilassie, Solomon; Hussien, Abdelwasie; Hagos, Miruts; Amare, Kasa; Deckers, Jozef; Gebrehiwot, Kindeya

    2013-08-01

    The Geba basin is one of the most water-stressed areas of Ethiopia, with only a short rainy period from mid-June to mid-September. Because rainfall in this region has been consistently erratic in the last decades, both in time and space, rain-fed agriculture has become problematic. Hence, in order to supplement rain-fed agriculture by irrigation, a detailed understanding of local and regional surface water and groundwater resources is important. The main objective of this study is to assess the available water resources in the Geba basin using a spatially distributed water balance model (WetSpass). Relevant input data for the model is prepared in the form of digital maps using remote sensing images, GIS tools, FAO and NASA databases, field reconnaissance and processing of meteorological and hydrological observations. The model produces digital maps of long-term average, seasonal and annual surface runoff, evapotranspiration and groundwater recharge. Results of the model show that 76% of the precipitation in the basin is lost through evapotranspiration, 18% becomes surface runoff and only 6% recharges the groundwater system. Model predictions are verified against river flow observations and are shown to be reliable. Additional maps are derived of accumulated surface runoff, safe yield for groundwater abstraction and water deficit for crop growth. Comparison of existing reservoirs with the accumulated runoff map shows that many reservoirs have failed because their design capacity is much higher than the actual inflow. Comparison of the safe yield map with the crop water deficit map shows that in most areas groundwater can be safely abstracted to supplement the water deficit for crop growth during the wet summer season. However, in the dry winter season the crop water deficit is too high to be supplemented by groundwater abstraction in a sustainable way.

  15. The Effect of El Niño on Agricultural Water Balances in Guatemala

    NASA Astrophysics Data System (ADS)

    Pedreros, D.; Michaelsen, J.; Carvalho, L. V.; Funk, C. C.; Husak, G. J.

    2010-12-01

    More than half the population of Guatemala lives in rural areas and depends on subsistence agriculture for their well being. This region is vulnerable to many climatic events, one of which is El Niño. This study looks at the effects of El Nino on rainfall patterns at regional scales and specifically quantifies the effects on agricultural water balances in Guatemala. Analysis is focused on maize crops during the Primera growing season (May - July). The study builds on rainfall and water balance modeling techniques developed by the Famine Early Warning Systems Network (FEWS NET). The results corroborate previous work, showing that there is a negative relationship between El Niño and rainfall, primarily on the Pacific side of the region and mainly during the months of August and September. The study also found that the related rainfall variations influence long-term (May - October) maize growing areas and could affect the start of the short-term Postrera season (August - October) by extending the Canícula. Correlation between rainfall and the Oceanic Niño Index (ONI) for the month of August in Central America.

  16. Africa-wide water balance estimation using remote sensing and global weather datasets

    NASA Astrophysics Data System (ADS)

    Senay, G. B.; Pengra, B.; Bohms, S.; Singh, A.; Verdin, J. P.

    2010-12-01

    The continent of Africa encompasses diverse ecological systems - from desert to equatorial forest - with major rivers flowing in different directions such as the Congo, Niger, Nile, Senegal and Zambezi. A lack of consistent data or access to important data sets such as rainfall, stream flow and evapotranspiration has been a barrier to developing Africa-wide water atlas in the past. We used globally available and consistent weather and remotely sensed datasets to estimate annual average (2001-2009) actual evapotranspiration (ET) at 1 km scale for the entire continent from the 8-day ET estimates using the Simplified Surface Energy Balance (SSEB) model. Thermal and optical remotely sensed data from the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor were used. Annual rainfall was generated from the widely used climatological monthly rainfall summaries developed by FAO (1961-1990) at 10 km resolution. Spatially explicit annual water balance was calculated as the difference between annual rainfall and actual ET at 1 km resolution. The result was summarized by major river basins to estimate the relative contribution of the riparian countries in the basin. From this study, we estimated the total annual runoff depth for Africa to be a depth of 142.5 mm or 4,483 km3 (using a continental area of 30.65 km2). This figure compares within 4 percent of an average runoff estimate reported in the literature.

  17. Water Balance and Residence Time in Stream Functional Units of Differing Scales

    NASA Astrophysics Data System (ADS)

    Payn, R. A.; Gooseff, M. N.; McGlynn, B. L.; Bencala, K. E.; Wondzell, S. M.; Jencso, K.

    2005-12-01

    We are beginning investigations of relationships between stream-groundwater interactions and valley structure. Ultimately, these analyses will generate a conceptual foundation for scaling hydraulics of a stream functional unit to hydrodynamics of a watershed stream network. Our preliminary goal is to establish methods that quantify spatially explicit water balances and solute transport characteristics from stream reach to network scales. During summer of 2005, we employed simultaneous conservative tracer injections of Rhodamine WT at a constant rate and distributed chloride slugs. Breakthrough curves from these injections were used to characterize solute transport at spatial scales ranging from minimal mixing reaches (ca. 5-20 m) to the entire length of 2 headwater tributaries (ca. 3 km) in the Tenderfoot Creek Experimental Forest (USFS), Little Belt Mountains, Montana. In one tributary, results from multiple slug injections include net discharge changes ranging from -19% to +68% and tracer mass losses ranging from 2% to 40% over 28 adjacent 100-m reaches. In another tributary, chloride slug injections performed during plateau of a Rhodamine WT constant rate injection also suggest distributed variability in discharge change and tracer loss. Water balance variability at small scales within simultaneously measured large scale response allows us to explore how small scale hydrologic function operates within and contributes to the large scale context. In the future, terrain analysis of LIDAR and topographic survey data will be used to evaluate the dependence of hydrologic function on morphologic structure from channel to valley scales.

  18. Water-balance response of Rhinella arenarum (Hensel, 1867) tadpoles to graduated increase in environmental osmolarity.

    PubMed

    Ferrari, L; de la Torre, F R; Salibián, A

    2010-02-01

    The water balance and the upper limit of osmotic tolerance of premetamorphic Rhinella arenarum larvae (Gosner's stage 26) was evaluated after semistatic incubation in electrolyte (NaCl) and non-electrolyte (mannitol) media following a protocol of progressively increased osmotic pressure. Wet and dry weights were measured to calculate the water content as a derived variable indicative of the hydric balance. Statistical analysis was performed using univariate and integrated multivariate analysis. Tadpoles survived in electrolyte and non-electrolyte solutions up to 200 mOsm. The discriminant function was the best tool to describe the responses of the animals to external environmental stress under experimental conditions. The results were compared with those obtained in previous studies using a protocol of acute exposure to the same media used in this study. It was concluded that a) multivariate analysis is an appropriate approach to describe the responses of tadpoles to changes in the environmental physicochemical parameters, and b) progressive and acute acclimation to the experimental solutions induced similar responses. PMID:20231975

  19. Magnetic hydrophilic-lipophilic balance sorbent for efficient extraction of chemical warfare agents from water samples.

    PubMed

    Singh, Varoon; Purohit, Ajay Kumar; Chinthakindi, Sridhar; Goud D, Raghavender; Tak, Vijay; Pardasani, Deepak; Shrivastava, Anchal Roy; Dubey, Devendra Kumar

    2016-02-19

    Magnetic hydrophilic-lipophilic balance (MHLB) hybrid resin was prepared by precipitation polymerization using N-vinylpyrrolidone (PVP) and divinylbenzene (DVB) as monomers and Fe2O3 nanoparticles as magnetic material. These resins were successfully applied for the extraction of chemical warfare agents (CWAs) and their markers from water samples through magnetic dispersive solid-phase extraction (MDSPE). By varying the ratios of monomers, resin with desired hydrophilic-lipophilic balance was prepared for the extraction of CWAs and related esters of varying polarities. Amongst different composites Fe2O3 nanoparticles coated with 10% PVP+90% DVB exhibited the best recoveries varying between 70.32 and 97.67%. Parameters affecting the extraction efficiencies, such as extraction time, desorption time, nature and volume of desorption solvent, amount of extraction sorbent and the effect of salts on extraction were investigated. Under the optimized conditions, linearity was obtained in the range of 0.5-500 ng mL(-1) with correlation ranging from 0.9911-0.9980. Limits of detection and limits of quantification were 0.5-1.0 and 3.0-5.0 ng mL(-1) respectively with RSDs varying from 4.88-11.32% for markers of CWAs. Finally, the developed MDSPE method was employed for extraction of analytes from water samples of various sources and the OPCW proficiency test samples. PMID:26814366

  20. Effect of urbanisation on the water balance of a catchment with shallow groundwater

    NASA Astrophysics Data System (ADS)

    Barron, O. V.; Barr, A. D.; Donn, M. J.

    2013-04-01

    SummaryThe impact of urbanisation on the water balance of a catchment dominated by surface water and groundwater interactions was investigated by using a process-based coupled surface water and groundwater model called MODHMS. The modelling estimated the likely changes in river discharge as a result of the land use change in the Southern River catchment in Western Australia. The catchment has both permeable soils and a shallow watertable. There was a significant increase in total annual discharge from the urbanised area where the runoff coefficient rose from 0.01 to more than 0.40. However in contrast with urban areas elsewhere these changes were mainly due to a shift in the subsurface water balance, including both groundwater and the unsaturated zone due to specifics of local hydrogeological conditions and adopted practice of storm runoff management. Due to the highly permeable soils, it is also common practice in the local building industry to direct runoff from roofs and roads into the soil and thereby the unconfined aquifer. Urbanisation results in particularly large changes in evapotranspiration from the soil profile and shallow watertable. The total subsurface evaporative flux reduced from 90% of infiltration (or 63-68% rainfall) to less than 29% (or 20% of rainfall) after urbanisation. Up to 83% (or 443 mm) of the pre-development evapotranspiration flux was from the shallow watertable. The requirement to control groundwater levels with drains in the shallow unconfined aquifer as well as the introduction of impervious surfaces caused a significant reduction of this component of evapotranspiration to less than 154 mm. These combined with an increase in infiltration rates, due to the direct infiltration of roof and road runoff, lead to higher groundwater recharge rates and subsequently groundwater discharge to the urban drainage network. The magnitude of urbanisation on catchment fluxes is most strongly influenced by urban density and the rate of local

  1. Impacts of climate change on the water balance of a large nonhumid natural basin in China

    NASA Astrophysics Data System (ADS)

    Liu, Qiang; Liang, Liqiao

    2015-08-01

    Water resources are contingent on the combined effects of climate change and watershed characteristics. An analytical model devised from the Budyko framework was used to investigate the partitioning of precipitation ( P) into actual evapotranspiration ( E) and streamflow ( Q) parameters for the Yellow River Basin (YRB), a water-limited basin, to estimate the response of E and Q to P and potential evapotranspiration ( E p ). Although a steady state was assumed, the analytical model, incorporating an adjustable parameter characteristic of catchment conditions ( ω), can be run to analyze the sensitivity of catchment characteristics on water resources. The theory predicts that Q and E are more sensitive to P than to E p . For example, a 10 % increase in P will result in a 22.8 % increase in Q, while a 10 % increase in E p will decrease Q by 13.2 %. The model shows that, to some extent, water balance is governed by changing catchment characteristics (such as changes in vegetation on annual scales). These findings indicate that additional elucidative data can be drawn from the Budyko framework when taking into account catchment characteristics. Furthermore, the model can analyze the response of water resources to climate change on different temporal and spatial scales.

  2. Continental freshwater discharge estimates from satellite observations and terrestrial water balance

    NASA Astrophysics Data System (ADS)

    Munier, S.; Cazenave, A. A.; Maisongrande, P.

    2011-12-01

    Freshwater discharge is a key component of the global water cycle. During the last few decades, remotely sensed hydro-climatic data has given the opportunity to overcome the numerous technical, political and economical challenges raised by ground-based observation networks. In the present study, we used satellite observations combined with atmospheric reanalysis in a coupled ocean-land-atmosphere water mass balance to estimate freshwater discharge over the last few years at basin, continental and global scales. Variations in terrestrial water storage (TWS) are provided by the Gravity Recovery and Climate Experiment (GRACE) mission, whereas precipitation minus evapotranspiration (P-E) is computed from atmospheric reanalyses (NCEP-NCAR and ECMWF datasets). In order to assess the accuracy of freshwater discharge estimates, uncertainties in each terms of the water balance are explored. GRACE-derived TWS is compared to outputs of Land Surface Models (GLDAS, WGHM and ISBA), keeping in mind that LSMs generally do not account for human-induced effects on the hydrological cycle. Independently, reanalysis-based P-E is compared to remotely sensed and/or in situ observations of precipitation (GPCC, GPCP, CMAP), evaporation over oceans (OAFlux, HOAPS) and modeled evapotranspiration over land (Penman-Monteith and Priestley-Taylor). Finally, freshwater discharge estimates are compared to in situ discharge observations from GRDC and to estimates from previous global studies. Discrepancies between the different datasets, in terms of annual mean as well as seasonal and inter-annual variability, allowed us to draw uncertainty maps, then highlighting regions where freshwater discharge estimates are the most uncertain. Such results may help to focus future developments on hydrological modeling for further improvement in freshwater discharge estimates.

  3. Aedes aegypti Global Suitability Maps Using a Water Container Energy Balance Model for Dengue Risk Applications

    NASA Astrophysics Data System (ADS)

    Steinhoff, D.

    2015-12-01

    Dengue infections are estimated to total nearly 400 million per year worldwide, with both the geographic range and the magnitude of infections having increased in the past 50 years. The primary dengue vector mosquito Aedes aegypti is closely associated with humans. It lives exclusively in urban and semi-urban areas, preferentially bites humans, and spends its developmental stages in artificial water containers. Climate regulates the development of Ae. aegypti immature mosquitoes in artificial containers. Potential containers for Ae. aegypti immature development include, but are not limited to, small sundry items (e.g., bottles, cans, plastic containers), buckets, tires, barrels, tanks, and cisterns. Successful development of immature mosquitoes from eggs to larvae, pupae, and eventually adults is largely dependent on the availability of water and the thermal properties of the water in the containers. Recent work has shown that physics-based approaches toward modeling container water properties are promising for resolving the complexities of container water dynamics and the effects on immature mosquito development. An energy balance container model developed by the author, termed the Water Height And Temperature in Container Habitats Energy Model (WHATCH'EM), solves for water temperature and height for user-specified containers with readily available weather data. Here we use WHATCH'EM with NASA Earth Science products used as input to construct global suitability maps based on established water temperature ranges for immature Ae. aegypti mosquitoes. A proxy for dengue risk is provided from habitat suitability, but also population estimates, as Ae. aegypti is closely associated with human activity. NASA gridded Global Population of the World data is used to mask out rural areas with low dengue risk. Suitability maps are illustrated for a variety of containers (size, material, color) and shading scenarios.

  4. A Scalable Water Balance Model Within the Russian River, California, Basin

    NASA Astrophysics Data System (ADS)

    Hunt, J. R.

    2007-12-01

    The availability of long term hydrologic data sets provides opportunities for quantifying hydrologic variability and examining evidence for changing conditions following land surface alterations and climate change. The Russian River basin in California is typical of many watersheds on the fringe of expanding metropolitan regions with competing demands for water from municipal, agricultural, recreational, and environmental constituencies. The Russian River basin is convenient for analysis because there is limited water imported and exported. One of the major challenges faced by water resources engineers within this basin is to understand the conditions necessary for the restoration of salmon and steelhead trout that have life cycles dependent upon migrations between the upper reaches of the watershed and the Pacific Ocean. The amount, timing and duration of surface water flows are frequently cited as some of the key factors controlling fishery health and recovery. The Russian River basin has numerous long-term data sets on flow, precipitation and water quality measures that have been gathered into a data cube for analysis and synthesis. Results to date have focused on comparing annual water balances for sub-watersheds that span over an order of magnitude in area. The data reveal a simple scalable relationship that annual runoff depth equals annual precipitation minus approximately 450 mm of water. This 450 mm of annual water demand represents a basin-wide integration of soil and groundwater dynamics and transpiration by vegetation. There is little evidence of human alteration of this relationship over a 60 year record. This scalable relationship is used to investigate how runoff from the basin would respond to changes in annual precipitation.

  5. Impact of climate change on water balance components in Mediterranean rainfed olive orchards under tillage or cover crop soil management

    NASA Astrophysics Data System (ADS)

    Rodríguez-Carretero, María Teresa; Lorite, Ignacio J.; Ruiz-Ramos, Margarita; Dosio, Alessandro; Gómez, José A.

    2013-04-01

    The rainfed olive orchards in Southern Spain constitute the main socioeconomic system of the Mediterranean Spanish agriculture. These systems have an elevated level of complexity and require the accurate characterization of crop, climate and soil components for a correct management. It is common the inclusion of cover crops (usually winter cereals or natural cover) intercalated between the olive rows in order to reduce water erosion. Saving limited available water requires specific management, mowing or killing these cover crops in early spring. Thus, under the semi-arid conditions in Southern Spain the management of the cover crops in rainfed olive orchards is essential to avoid a severe impact to the olive orchards yield through depletion of soil water. In order to characterize this agricultural system, a complete water balance model has been developed, calibrated and validated for the semi-arid conditions of Southern Spain, called WABOL (Abazi et al., 2013). In this complex and fragile system, the climate change constitutes a huge threat for its sustainability, currently limited by the availability of water resources, and its forecasted reduction for Mediterranean environments in Southern Spain. The objective of this study was to simulate the impact of climate change on the different components of the water balance in these representative double cropping systems: transpiration of the olive orchard and cover crop, runoff, deep percolation and soil water content. Four climatic scenarios from the FP6 European Project ENSEMBLES were first bias corrected for temperatures and precipitation (Dosio and Paruolo, 2011; Dosio et al., 2012) and, subsequently, used as inputs for the WABOL model for five olive orchard fields located in Southern Spain under different conditions of crop, climate, soils and management, in order to consider as much as possible of the variability detected in the Spanish olive orchards. The first results indicate the significant effect of the cover

  6. Comparative analysis of the actual evapotranspiration of Flemish forest and cropland, using the soil water balance model WAVE

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Muys, B.; Feyen, J.; Veroustraete, F.; Minnaert, M.; Meiresonne, L.; de Schrijver, A.

    2005-05-01

    This paper focuses on the quantification of the green - vegetation related - water flux of a forest stand in the temperate lowland of Flanders. The underlying reason of the research was to develop a methodology for assessing the impact of forests on the hydrologic cycle in comparison to agriculture. The approach tested for calculating the water consumption by forests was based on the application of the soil water balance model WAVE. The study involved the collection of data from 14 forest stands, the calibration and validation of the WAVE model, and the comparison of the water use (WU) components - transpiration, soil and interception evaporation - between forest and cropland. For model calibration purposes simulated and measured time series of soil water content at different soil depths, period March 2000-August 2001, were compared. A multiple-site validation was conducted as well. Actual tree transpiration calculated with sap flow measurements in three forest stands gave similar results for two of the three stands of pine (Pinus sylvestris L.), but WAVE overestimated the actual measured transpiration for a stand of poplar (Populus sp.). A useful approach to compare the WU components of forest versus cropland is scenario analysis based on the validated WAVE model. The statistical Profile Analysis method was implemented to explore and analyse the simulated WU time-series. With an average annual rainfall of 819 mm, the results show that forests in Flanders consume more water than agricultural crops. A 30 years average of 491 mm for 10 forests stands versus 398 mm for 10 cropped agricultural fields was derived. The WU components, on yearly basis, also differ between the two land use types (transpiration: 315 mm for forest and 261 mm for agricultural land use; soil evaporation: 47 mm and 131 mm, for forest and cropland, respectively). Forest canopy interception evaporation was estimated at 126 mm, while it was negligible for cropland.

  7. Comparative analysis of the actual evapotranspiration of Flemish forest and cropland, using the soil water balance model WAVE

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Muys, B.; Feyen, J.; Veroustraete, F.; Minnaert, M.; Meiresonne, L.; de Schrijver, A.

    2005-09-01

    This paper focuses on the quantification of the green - vegetation related - water flux of forest stands in the temperate lowland of Flanders. The underlying reason of the research was to develop a methodology for assessing the impact of forests on the hydrologic cycle in comparison to agriculture. The tested approach for calculating the water use by forests was based on the application of the soil water balance model WAVE. The study involved the collection of data from 14 forest stands, the calibration and validation of the WAVE model, and the comparison of the water use (WU) components - transpiration, soil and interception evaporation - between forest and cropland. For model calibration purposes simulated and measured time series of soil water content at different soil depths, period March 2000-August 2001, were compared. A multiple-site validation was conducted as well. Actual tree transpiration calculated with sap flow measurements in three forest stands gave similar results for two of the three stands of pine (Pinus sylvestris L.), but WAVE overestimated the actual measured transpiration for a stand of poplar (Populus sp.). A useful approach to compare the WU components of forest versus cropland is scenario analysis based on the validated WAVE model. The statistical Profile Analysis method was implemented to explore and analyse the simulated WU time series. With an average annual rainfall of 819 mm, the results reveal that forests in Flanders consume more water than agricultural crops. A 30 years average of 491 mm for 10 forests stands versus 398 mm for 10 cropped agricultural fields was derived. The WU components, on yearly basis, also differ between the two land use types (transpiration: 315 mm for forest and 261 mm for agricultural land use; soil evaporation: 47 mm and 131 mm, for forest and cropland, respectively). Forest canopy interception evaporation was estimated at 126 mm, while it was negligible for cropland.

  8. Animal water balance drives top-down effects in a riparian forest-implications for terrestrial trophic cascades.

    PubMed

    McCluney, Kevin E; Sabo, John L

    2016-08-17

    Despite the clear importance of water balance to the evolution of terrestrial life, much remains unknown about the effects of animal water balance on food webs. Based on recent research suggesting animal water imbalance can increase trophic interaction strengths in cages, we hypothesized that water availability could drive top-down effects in open environments, influencing the occurrence of trophic cascades. We manipulated large spider abundance and water availability in 20 × 20 m open-air plots in a streamside forest in Arizona, USA, and measured changes in cricket and small spider abundance and leaf damage. As expected, large spiders reduced both cricket abundance and herbivory under ambient, dry conditions, but not where free water was added. When water was added (free or within moist leaves), cricket abundance was unaffected by large spiders, but spiders still altered herbivory, suggesting behavioural effects. Moreover, we found threshold-type increases in herbivory at moderately low soil moisture (between 5.5% and 7% by volume), suggesting the possibility that water balance may commonly influence top-down effects. Overall, our results point towards animal water balance as an important driver of direct and indirect species interactions and food web dynamics in terrestrial ecosystems. PMID:27534953

  9. Annual mesoscale study of water balance in a Great Basin heterogeneous desert valley

    NASA Astrophysics Data System (ADS)

    Malek, E.; Bingham, G. E.; Or, D.; McCurdy, G.

    1997-04-01

    We studied the annual mesoscale water balance in northeastern Nevada, USA, in a Great Basin heterogeneous semi-arid desert valley (the Goshute Valley) at 40°44'N, 114°26'W, witgh elevation of 1707 m above mean sea-level. This north-south-oriented flat valley has an area of about 1113 km 2 and is partially covered mostly by sagebrush, greasewood, shadscale, desert molly, cheatgrass, and winter fat bushes. Five Bowen ratio stations measured the incoming and outgoing (reflected) solar radiation, net radiation, air temperatures and moisture at 1 and 2 m, the aggregated (soil + vegetation) surface temperature, wind speed and direction at 10 m, soil heat flux at 8 cm (three locations at each station), soil temperatures at 2 and 6 cm above each soil flux plate, and precipitation every 5 s averaged to 20 min throughout the valley from 1 May 1993 to 30 September 1994. Locations of stations were based upon the vegetation types and percentage of coverage by bushes. The topsoil (10 cm) moisture content was measured either by time domain reflectometer or gravimetric method at least once a week. We used the Bowen ratio energy balance (BREB) method for the measurement of 20 min evapotranspiration throughout the experiment. During the dry water year 1993-1994 (beginning from 1 October) the average amount of aggregated (soil + bushes) evapotranspiration ( ETa) among stations measured by the BREB method was almost equal to the average total precipitation for the entire valley (160.9 mm vs. 157.7 mm, respectively). Variations of precipitation among stations (ranging from 173.7 mm at Station 2 to 130.5 mm at Station 1) were attributed to winter orographic effects and summer thermal lows. ETa ranged from 181.2 mm at Station 3 to 142.7 mm at Station 2. Variations were related mostly to vegetation types and percentage of the soil coverage. All stations showed slight water losses ( ETa greater than precipitation) in the dry water year 1993-1994, except at Station 2, where water gain was

  10. Runoff Regime Prediction: a Water Balance Approach for High Elevation Basins

    NASA Astrophysics Data System (ADS)

    Bartolini, E.; Allamano, P.; Claps, P.; Laio, F.

    2009-05-01

    Runoff regime, intended as the curve of the mean monthly runoff values, is a valuable information for the control of water management strategies. The increasing competition between different water uses and the recognized need for a sustainable resources exploitation require an improvement in the runoff prediction procedures also for regions, as the European Alps, historically characterized by abundant water resources. Moreover, threats of global temperature increase include specific modifications of the regime, that can affect water uses based on runoff regularity. For mountain catchments, however, runoff prediction is made complex by the topographic heterogeneities, the dynamics of snow accumulation and melt, and the high spatial precipitation variability, generally poorly described by the measurements networks. In this paper we present a parsimonious (i.e. characterized by a limited number of parameters) water balance model conceived for mountain basins that uses widely available input data (mean monthly temperature and precipitation). The model works on a monthly scale but we introduce a statistical representation of the within- month temperature variability to take into account the effects of the above- and below-zero frequency on the snow accumulation. In fact, the modeling scheme contains a specific snow accumulation and melt module that allows to partition precipitation into snow and rainfall and to assess snowmelt volumes based on a temperature threshold mechanism. Runoff is obtained as the sum of two contributes: net precipitation (rainfall minus evapotranspiration) and snowmelt. A parametric procedure to correct precipitation measurements due to snow undercatch is also proposed. To assess the performances of the model we apply it to a sample of catchments located in the Western Italian Alps and we compare the simulated and observed runoff regimes in terms of mean absolute error. The model proves able to describe the timing and shape of the regime for most

  11. The Role of Climatic Variability on Rio Grande Salinity and Water Balances

    NASA Astrophysics Data System (ADS)

    Hogan, J. F.; Phillips, F. M.

    2008-12-01

    The upper Rio Grande/ Rio Bravo extends ~1,200 km between its headwaters in southern Colorado (USA) and the USA/Mexico border region. Like many arid region rivers, it exhibits reductions in streamflow and degrading water quality with distance downstream as a result of decreasing inflows, increasing evapotranspiration, and the addition of natural and anthropogenic solutes. From 2000 to 2007 we conducted detailed biannual synoptic sampling of the Rio Grande from its headwaters in Colorado to ~150 km south of El Paso, Texas to evaluate how these processes result in the observed basin-scale water and solute balances. This period coincides with a severe regional drought, as well as the 8th wettest summer monsoon in the region, allowing us to assess how basin processes which control water quality respond to periods of climatic variability. We employed multiple environmental tracers to help identify dominant hydrological processes and the causes of salinization. Our O and H isotopic results indicate that runoff from high-elevation areas in Colorado and northern New Mexico - primarily as snowmelt - is the dominant source of river water, although runoff from summer precipitation can be locally and seasonally significant. This water then exhibits progressive evaporation with distance downstream, with the greatest evaporation occurring at Elephant Butte Reservoir. At the same time, the total dissolved solids content (TDS) increases from less than 50 mg/L in headwaters of Colorado to over 2000 mg/L south of El Paso, Texas. Water balance estimates and our O and H isotope results indicate that evapotranspiration alone is not sufficient to explain the salinization. The results of our synoptic surveys found that salinity did not increase as a simple function of distance downriver but rather occurred in a series of steps, identified as discharge of deep, saline, ground water. During the course of the drought we observed a progressive increase in salt concentrations and more

  12. Healthy Water Healthy People Field Monitoring Guide

    ERIC Educational Resources Information Center

    Project WET Foundation, 2003

    2003-01-01

    This 100-page manual serves as a technical reference for the "Healthy Water, Healthy People Water Quality Educators Guide" and the "Healthy Water Healthy People Testing Kits". Yielding in-depth information about ten water quality parameters, it answers questions about water quality testing using technical overviews, data interpretation guidelines,…

  13. Actual evapotranspiration (water use) assessment of the Colorado River Basin at the Landsat resolution using the operational simplified surface energy balance model

    USGS Publications Warehouse

    Singh, Ramesh K.; Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Russell L, Scott; Verdin, James P.

    2014-01-01

    Accurately estimating consumptive water use in the Colorado River Basin (CRB) is important for assessing and managing limited water resources in the basin. Increasing water demand from various sectors may threaten long-term sustainability of the water supply in the arid southwestern United States. We have developed a first-ever basin-wide actual evapotranspiration (ETa) map of the CRB at the Landsat scale for water use assessment at the field level. We used the operational Simplified Surface Energy Balance (SSEBop) model for estimating ETa using 328 cloud-free Landsat images acquired during 2010. Our results show that cropland had the highest ETa among all land cover classes except for water. Validation using eddy covariance measured ETa showed that the SSEBop model nicely captured the variability in annual ETa with an overall R2 of 0.78 and a mean bias error of about 10%. Comparison with water balance-based ETa showed good agreement (R2 = 0.85) at the sub-basin level. Though there was good correlation (R2 = 0.79) between Moderate Resolution Imaging Spectroradiometer (MODIS)-based ETa (1 km spatial resolution) and Landsat-based ETa (30 m spatial resolution), the spatial distribution of MODIS-based ETa was not suitable for water use assessment at the field level. In contrast, Landsat-based ETa has good potential to be used at the field level for water management. With further validation using multiple years and sites, our methodology can be applied for regular production of ETa maps of larger areas such as the conterminous United States.

  14. Time-Scale Invariance As an Emergent Property in Water Balance

    NASA Astrophysics Data System (ADS)

    Wang, D.; Tang, Y.

    2014-12-01

    The Darwinian modeling approach seeks to explain the behavior of a hydrologic system as a whole by identifying simple and robust temporal or spatial patterns that capture the relevant processes. Darwinian-based hydrologic models include the Soil Conservation Service (SCS) curve number model, the "abcd" model, and the Budyko-type models. However, these models were developed based on widely differing principles and assumptions and applied to distinct time scales. Here, we derive a one-parameter Budyko-type model for mean annual water balance which is based on a generalization of the proportionality hypothesis of the SCS model and therefore is independent of temporal scale. Furthermore, we show that the new model is equivalent to the key equation of the "abcd" model. Theoretical lower and upper bounds of the new model are identified and validated based on previous observations. Thus, we illustrate a time-scale invariance property in water balance, which allows for synthesis with the Newtonian approach and offers opportunities for progress in hydrologic modeling. In the derivation of Budyko equation, total evaporation is divided into initial evaporation (E0) and continuing evaporation. Runoff does not compete with initial evaporation for water storage by interception and top soils. The assumption behind the derived equation is that the ratio of continuing evaporation to its potential value is equal to the ratio of runoff to the maximum possible value of runoff. The derived equation satisfies the boundary conditions of Budyko hypothesis, and includes one parameter (ɛ). From the perspective of evaporation, is the ratio between initial evaporation and total evaporation; from the soil wetting (W) perspective, e can be interpreted as the ratio between initial evaporation ratio (λ =E0/W) and Horton index (H=E/W), i.e. ɛ =λ/H. H is dominantly controlled by vegetation represented by NDVI; l is found to increase with decreasing product between NDVI and the fraction of rainy

  15. Climate Change Impact on Water Balance at the Chipola River Watershed in Florida

    NASA Astrophysics Data System (ADS)

    Griffen, J. M.; Chen, X.; Wang, D.; Hagen, S. C.

    2013-12-01

    As the largest tributary to the Apalachicola River, the Chipola River originates in southern Alabama, flows through the Florida Panhandle and drains into the Gulf of Mexico. The Chipola watershed is located in an intermediate climate environment with an aridity index of approximately 1.0. However, climate change affects the hydrologic cycle of Chipola River watershed at various temporal and spatial scales. Studying the effects of climate variations is of great importance for water and environmental management purposes in this watershed. This research is mainly focused on assessing climate change impact on the partitioning of rainfall and the following runoff generation in Chipola watershed, from long-term mean annual to inter-annual and to seasonal and monthly scales. A comprehensive water balance model at inter-annual scale is built in this study based on Budyko's framework, two-stage runoff theory and proportionality hypothesis. The inter-annual scale model considers the impact of storage change, seasonality and landscape controls, which are normally assumed to be negligible on a long-term scale. The model is applied to the Chipola River Watershed in Florida to project future water balance pattern with the input from a Regional Climate Model projection. Based on the projection results: evaporation will increase in the future in all 12 months; runoff will increase only in dry months of July to October, while significantly decrease in wet months of December to April; storage change will increase in wet months of January to April, while decrease in the dry months of August to November.

  16. Soil nitrogen balance under wastewater management: Field measurements and simulation results

    USGS Publications Warehouse

    Sophocleous, M.; Townsend, M.A.; Vocasek, F.; Ma, L.; KC, A.

    2009-01-01

    The use of treated wastewater for irrigation of crops could result in high nitrate-nitrogen (NO3-N) concentrations in the vadose zone and ground water. The goal of this 2-yr field-monitoring study in the deep silty clay loam soils south of Dodge City, Kansas, was to assess how and under what circumstances N from the secondary-treated, wastewater-irrigated corn reached the deep (20-45 m) water table of the underlying High Plains aquifer and what could be done to minimize this problem. We collected 15.2-m-deep soil cores for characterization of physical and chemical properties; installed neutron probe access tubes to measure soil-water content and suction lysimeters to sample soil water periodically; sampled monitoring, irrigation, and domestic wells in the area; and obtained climatic, crop, irrigation, and N application rate records for two wastewater-irrigated study sites. These data and additional information were used to run the Root Zone Water Quality Model to identify key parameters and processes that influence N losses in the study area. We demonstrated that NO3-N transport processes result in significant accumulations of N in the vadose zone and that NO3-N in the underlying ground water is increasing with time. Root Zone Water Quality Model simulations for two wastewater-irrigated study sites indicated that reducing levels of corn N fertilization by more than half to 170 kg ha-1 substantially increases N-use efficiency and achieves near-maximum crop yield. Combining such measures with a crop rotation that includes alfalfa should further reduce the accumulation and downward movement of NO3-N in the soil profile. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  17. Linking soil water balance and water age with leaching of nitrate to groundwater in an agricultural setting

    NASA Astrophysics Data System (ADS)

    Sigler, W.; Ewing, S. A.; Payn, R. A.; Jones, C. A.; Weissmann, G. S.

    2013-12-01

    The effects of land management on groundwater chemistry are often poorly understood due to uncertainties about residence times of water and solutes in the unsaturated and the saturated zones. In central Montana, a strath terrace mantled with 20-100 cm of loess-derived clay loam is composed of 5-10 meters of gravel hosting a shallow aquifer overlying shale. The landform is isolated from mountain front stream recharge and drained by springs at the gravel/shale interface surrounding the terrace. Ninety three percent of the terrace surface is cultivated, predominantly for production of small grains. A typical cropping system on the terrace is a three year rotation of winter wheat, spring wheat or barley, and fallow, where each phase represents a different regime of evapotranspiration, recharge, fertilizer application, mineralization and nitrate leaching to groundwater. Age of water in discharge from the perched aquifer in the gravel can potentially be characterized by monitoring springs and streams that are ultimately sourced by infiltration and recharge across the terrace. Work presented here couples a simple daily soil water balance model with ground and surface water chemistry to infer travel times through the unsaturated and saturated zones. These results are evaluated against estimates of groundwater age derived from pool turnover time calculations, finite difference groundwater flow modeling, and use of chemical age tracers.

  18. Shifts in plant functional types have time-dependent and regionally variable impacts on dryland ecosystem water balance

    USGS Publications Warehouse

    Bradford, John B.; Schlaepfer, Daniel R.; Lauenroth, William K.; Burke, Ingrid C.

    2014-01-01

    5. Synthesis. This study provides a novel, regional-scale assessment of how plant functional type transitions may impact ecosystem water balance in sagebrush-dominated ecosystems of North America. Results illustrate that the ecohydrological consequences of changing vegetation depend strongly on climate and suggest that decreasing woody plant abundance may have only limited impact on evapotranspiration and water yield.

  19. Intergrated snow, soil and water-balance measurement strategy for multi-scale environmental observations in mountain areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The building of multiscale environmental observatory networks is a critical step in addressing the woefully inadequate observational infrastructure and understanding of mountain water balances. These networks will support science questions that need estimates of water reservoirs and fluxes at the po...

  20. Balancing the Budget: Accounting for Glucocorticoid Bioactivity and Fate during Water Treatment.

    PubMed

    Jia, Ai; Wu, Shimin; Daniels, Kevin D; Snyder, Shane A

    2016-03-15

    Numerous studies have identified the presence and bioactivity of glucocorticoid receptor (GR) active substances in water; however, the identification and activity-balance of GR compounds remained elusive. This study determined the occurrence and attenuation of GR bioactivity and closed the balance by determining those substances responsible. The observed in vitro GR activity ranged from 39 to 155 ng dexamethasone-equivalent/L (ng Dex-EQ/L) in the secondary effluents of four wastewater treatment plants. Monochromatic ultraviolet light of 80 mJ/cm(2) disinfection dose was efficient for GR activity photolysis, whereas chlorination could not appreciably attenuate the observed GR activity. Ozonation was effective only at relatively high dose (ozone/TOC 1:1). Microfiltration membranes were not efficient for GR activity attenuation; however, reverse osmosis removed GR activity to levels below the limits of detection. A high-sensitivity liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was then developed to screen 27 GR agonists. Twelve were identified and quantified in effluents at summed concentrations of 9.6-21.2 ng/L. The summed Dex-EQ of individual compounds based on their measured concentrations was in excellent agreement with the Dex-EQ obtained from bioassay, which demonstrated that the detected glucocorticoids can entirely explain the observed GR bioactivity. Four synthetic glucocorticoids (triamcinolone acetonide, fluocinolone acetonide, clobetasol propionate, and fluticasone propionate) predominantly accounted for GR activity. These data represent the first known publication where a complete activity balance has been determined for GR agonists in an aquatic environment. PMID:26840181

  1. A Bayesian Framework for Coupled Estimation of Key Unknown Parameters of Land Water and Energy Balance Equations

    NASA Astrophysics Data System (ADS)

    Farhadi, L.; Abdolghafoorian, A.

    2015-12-01

    The land surface is a key component of climate system. It controls the partitioning of available energy at the surface between sensible and latent heat, and partitioning of available water between evaporation and runoff. Water and energy cycle are intrinsically coupled through evaporation, which represents a heat exchange as latent heat flux. Accurate estimation of fluxes of heat and moisture are of significant importance in many fields such as hydrology, climatology and meteorology. In this study we develop and apply a Bayesian framework for estimating the key unknown parameters of terrestrial water and energy balance equations (i.e. moisture and heat diffusion) and their uncertainty in land surface models. These equations are coupled through flux of evaporation. The estimation system is based on the adjoint method for solving a least-squares optimization problem. The cost function consists of aggregated errors on state (i.e. moisture and temperature) with respect to observation and parameters estimation with respect to prior values over the entire assimilation period. This cost function is minimized with respect to parameters to identify models of sensible heat, latent heat/evaporation and drainage and runoff. Inverse of Hessian of the cost function is an approximation of the posterior uncertainty of parameter estimates. Uncertainty of estimated fluxes is estimated by propagating the uncertainty for linear and nonlinear function of key parameters through the method of First Order Second Moment (FOSM). Uncertainty analysis is used in this method to guide the formulation of a well-posed estimation problem. Accuracy of the method is assessed at point scale using surface energy and water fluxes generated by the Simultaneous Heat and Water (SHAW) model at the selected AmeriFlux stations. This method can be applied to diverse climates and land surface conditions with different spatial scales, using remotely sensed measurements of surface moisture and temperature states

  2. Water Balance Defines a Threshold in Soil Chemistry at a Global Scale

    NASA Astrophysics Data System (ADS)

    Slessarev, E.; Bingham, N.; Lin, Y.; Schimel, J.; Chadwick, O.

    2015-12-01

    Carefully constrained studies in model landscapes demonstrate the existence of pedogenic thresholds, where small changes in external forcing lead to large changes in soil properties. One important threshold defines the relationship between water balance, the availability of nutrient cations, and soil pH. Across rainfall gradients, the loss of alkali and alkaline earth cations occurs abruptly at a critical water-balance. At this threshold, the removal of exchangeable base cations by leaching outstrips their production from weathering, causing a drop in soil pH. This leaching threshold has never been characterized at a global scale, in part because of the tremendous sampling effort required to overcome the confounding effects of rock chemistry, soil age, and topography outside of carefully constrained environmental gradients. We compile an extensive database of soil pH measurements to show that there is a mean global leaching threshold near an annual water balance of zero. Where evaporative demand exceeds precipitation, soil pH is buffered near values of 8.1, but where precipitation exceeds evaporative demand, soil pH rapidly collapses to values near 5.0. Deviations from the threshold can be explained in terms of climatic variability, soil age, and rock chemistry. Regions with arid climates and acid soil pH correspond to zones of intense, periodic leaching (e.g. strongly monsoonal climates), or to highly weathered continental surfaces that have permanently lost their stock of cations (e.g. Australia). Regions with humid climates and neutral soil pH correspond to young landscapes, or to soils derived from base-rich rock (e.g. the Pacific Rim volcanic belt). These results demonstrate that the leaching threshold is a dominant feature of the Earth's surface, with the potential to affect both natural and human-dominated ecosystems. For instance: the leaching threshold might impose a step-function on the terrestrial response to CO2 fertilization, the capacity of soils to

  3. Quantification of non-stormwater flow entries into storm drains using a water balance approach.

    PubMed

    Xu, Zuxin; Yin, Hailong; Li, Huaizheng

    2014-07-15

    To make decisions about correcting illicit or inappropriate connections to storm drains, quantification of non-stormwater entries into storm drains was performed using a water flow balance approach, based on data analysis from 2008 to 2011 in a separate storm drainage system in a Shanghai downtown area of 374 ha. The study revealed severe sewage connections to storm drains; meanwhile, misconnections between surface water and storm drains were found to drive frequent non-stormwater pumping discharges at the outfall, producing a much larger volume of outfall flows in a short period. This paper presented a methodology to estimate quantities of inappropriate sewage flow, groundwater infiltration and river water backflow into the storm drains. It was concluded that inappropriate sewage discharge and groundwater seepage into storm drains were approximately 17,860 m(3)/d (i.e., up to 51% of the total sewage flow in the catchment) and 3,624 m(3)/d, respectively, and surface water backflow was up to an average 28,593 m(3)/d. On the basis of this work, end-of-storm pipe interceptor sewers of 0.25 m(3)/s (i.e., 21,600 m(3)/d) would be effective to tackle the problem of sewage connections and groundwater seepage to storm drains. Under this circumstance, the follow-up non-stormwater outfall pumping events indicate misconnections between surface water and storm drains, featuring pumping discharge equivalent to surface water backflow; hence the misconnections should be repaired. The information provided here is helpful in estimating the magnitude of non-stormwater flow entries into storm drains and designing the necessary pollution control activities, as well as combating city floods in storm events. PMID:24793842

  4. Glacier modeling in support of field observations of mass balance at South Cascade Glacier, Washington, USA

    USGS Publications Warehouse

    Josberger, Edward G.; Bidlake, William R.

    2010-01-01

    The long-term USGS measurement and reporting of mass balance at South Cascade Glacier was assisted in balance years 2006 and 2007 by a new mass balance model. The model incorporates a temperature-index melt computation and accumulation is modeled from glacier air temperature and gaged precipitation at a remote site. Mass balance modeling was used with glaciological measurements to estimate dates and magnitudes of critical mass balance phenomena. In support of the modeling, a detailed analysis was made of the "glacier cooling effect" that reduces summer air temperature near the ice surface as compared to that predicted on the basis of a spatially uniform temperature lapse rate. The analysis was based on several years of data from measurements of near-surface air temperature on the glacier. The 2006 and 2007 winter balances of South Cascade Glacier, computed with this new, model-augmented methodology, were 2.61 and 3.41 mWE, respectively. The 2006 and 2007 summer balances were -4.20 and -3.63 mWE, respectively, and the 2006 and 2007 net balances were -1.59 and -0.22 mWE. PDF version of a presentation on the mass balance of South Cascade Glacier in Washington state. Presented at the American Geophysical Union Fall Meeting 2010.

  5. Modeling efficiency and water balance in PEM fuel cell systems with liquid fuel processing and hydrogen membranes

    NASA Astrophysics Data System (ADS)

    Pearlman, Joshua B.; Bhargav, Atul; Shields, Eric B.; Jackson, Gregory S.; Hearn, Patrick L.

    Integrating PEM fuel cells effectively with liquid hydrocarbon reforming requires careful system analysis to assess trade-offs associated with H 2 production, purification, and overall water balance. To this end, a model of a PEM fuel cell system integrated with an autothermal reformer for liquid hydrocarbon fuels (modeled as C 12H 23) and with H 2 purification in a water-gas-shift/membrane reactor is developed to do iterative calculations for mass, species, and energy balances at a component and system level. The model evaluates system efficiency with parasitic loads (from compressors, pumps, and cooling fans), system water balance, and component operating temperatures/pressures. Model results for a 5-kW fuel cell generator show that with state-of-the-art PEM fuel cell polarization curves, thermal efficiencies >30% can be achieved when power densities are low enough for operating voltages >0.72 V per cell. Efficiency can be increased by operating the reformer at steam-to-carbon ratios as high as constraints related to stable reactor temperatures allow. Decreasing ambient temperature improves system water balance and increases efficiency through parasitic load reduction. The baseline configuration studied herein sustained water balance for ambient temperatures ≤35 °C at full power and ≤44 °C at half power with efficiencies approaching ∼27 and ∼30%, respectively.

  6. Multireservoir real-time operations for flood control using balanced water level index method.

    PubMed

    Wei, Chih-Chiang; Hsu, Nien-Sheng

    2008-09-01

    This paper presents a real-time simulation-optimization operation procedure for determining the reservoir releases at each time step during a flood. The proposed procedure involves two models, i.e., a hydrological forecasting model and a reservoir operation model. In the reservoir operation model, this paper compares two flood-control operation strategies for a multipurpose multireservoir system. While Strategy 1 is the real-time joint reservoir operations without using the balanced water level index (BWLI) method, Strategy 2 involves real-time joint reservoir operations using the BWLI method. The two strategies presented are formulated as mixed-integer linear programming (MILP) problems. The idea of using the BWLI method is derived from the HEC-5 program developed by the US Army Corps of Engineers. The proposed procedure has been applied to the Tanshui River Basin system in Taiwan using the 6h ahead forecast data of six typhoons. A comparison of the results obtained from the two strategies reveals that Strategy 2 performs much better than Strategy 1 in determining the reservoir real-time releases throughout the system during flood emergencies in order to minimize flooding, while maintaining all reservoirs in the system in balance if possible. Consequently, the proposed model using the BWLI method demonstrates its effectiveness in estimating real-time releases. PMID:17923249

  7. The Water, Energy and Food Nexus: Finding the Balance in Infrastructure Investment

    NASA Astrophysics Data System (ADS)

    Huber-lee, A. T.; Wickel, B.; Kemp-Benedict, E.; Purkey, D. R.; Hoff, H.; Heaps, C.

    2013-12-01

    There is increasing evidence that single-sector infrastructure planning is leading to severely stressed human and ecological systems. There are a number of cross-sectoral impacts in these highly inter-linked systems. Examples include: - Promotion of biofuels that leads to conversion from food crops, reducing both food and water security. - Promotion of dams solely built for hydropower rather than multi-purpose uses, that deplete fisheries and affect saltwater intrusion dynamics in downstream deltas - Historical use of water for cooling thermal power plants, with increasing pressure from other water uses, as well as problems of increased water temperatures that affect the ability to cool plants efficiently. This list can easily be expanded, as these inter-linkages are increasing over time. As developing countries see a need to invest in new infrastructure to improve the livelihoods of the poor, developed countries face conditions of deteriorating infrastructure with an opportunity for new investment. It is crucial, especially in the face of uncertainty of climate change and socio-political realities, that infrastructure planning factors in the influence of multiple sectors and the potential impacts from the perspectives of different stakeholders. There is a need for stronger linkages between science and policy as well. The Stockholm Environment Institute is developing and implementing practical and innovative nexus planning approaches in Latin America, Africa and Asia that brings together stakeholders and ways of integrating uncertainty in a cross-sectoral quantitative framework using the tools WEAP (Water Evaluation and Planning) and LEAP (Long-range Energy Alternatives Planning). The steps used include: 1. Identify key actors and stakeholders via social network analysis 2. Work with these actors to scope out priority issues and decision criteria in both the short and long term 3. Develop quantitative models to clarify options and balances between the needs and

  8. Toward improving global estimates of field soil water capacity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field capacity or field water capacity (FC) is defined as the water content of a soil after having been wetted with water and after free drainage is negligible. Different recommendations exist world-wide on which, if any, pressure head should be used in laboratory measurements to approximate the FC ...

  9. A worldwide evaluation of basin-scale evapotranspiration estimates against the water balance method

    NASA Astrophysics Data System (ADS)

    Liu, Wenbin; Wang, Lei; Zhou, Jing; Li, Yanzhong; Sun, Fubao; Fu, Guobin; Li, Xiuping; Sang, Yan-Fang

    2016-07-01

    Evapotranspiration (ET) plays a critical role in linking the water and energy cycles but is difficult to estimate at regional and basin scales. In this study, we present a worldwide evaluation of nine ET products (three diagnostic products, three land surface model (LSM) simulations and three reanalysis-based products) against reference ET (ETwb) calculated using the water balance method corrected for the water storage change at an annual time scale over the period 1983-2006 for 35 global river basins. The results indicated that there was no significant intra-category discrepancy in the annual ET estimates for the 35 basins calculated using the different products in 35 basins, but some products performed better than others, such as the Global Land surface Evaporation estimated using the Amsterdam Methodology (GLEAM_E) in the diagnostic products, ET obtained from the Global Land Data Assimilation System version 1 (GLDAS 1) with the Community Land Model scheme (GCLM_E) in LSM simulations, and ET from the National Aeronautics and Space Administration (NASA) Modern Era Retrospective-analysis for Research and Applications reanalysis dataset (MERRA_E) in the reanalysis-based products. Almost all ET products (except MERRA_E) reasonably estimated the annual means (especially in the dry basins) but systematically underestimated the inter-annual variability (except for MERRA_E, GCLM_E and ET simulation from the GLDAS 1 with the MOSAIC scheme - GMOS_E) and could not adequately estimate the trends (e.g. GCLM_E and MERRA_E) of ETwb (especially in the energy-limited wet basins). The uncertainties in nine ET products may be primarily attributed to the discrepancies in the forcing datasets and model structural limitations. The enhancements of global forcing data (meteorological data, solar radiation, soil moisture stress and water storage changes) and model physics (reasonable consideration of the water and energy balance and vegetation processes such as canopy interception loss

  10. Energy, water and carbon balance of managed forests: comparing the future to the past

    NASA Astrophysics Data System (ADS)

    Loustau, Denis; Moreaux, Virginie; Moisy, Christophe; Picart, Delphine; Lafont, Sébastien; Benest, Fabienne; Lagouarde, Jean-PIerre; Bosc, Alexandre

    2014-05-01

    Intensification of forest management concerns a growing fraction of temperate and tropical forests. It is thought to affect wider areas in the near future for facing biomass, fiber and wood demands. Intensively managed forests are submitted to increased soil preparation, fertilization, drainage, thinning, clear-cutting, whole tree - harvesting and rotation shortening. They are composed of fast growing stands commonly planted with enhanced tree varieties or clones of eucalypts, pines, poplars, willows among others. Altogether these practices have substantial effects on forest exchanges with atmosphere and groundwater and therefore on local and regional climates and water resources. Using data collected from flux tower sites, MODIS products and forest and soil inventories together with our process based model of forest growth, GO+, we analysed the impacts of intensified management on forest canopy exchanges of heat, short and longwave radiations, water and CO2 and its interaction with soil and climate. Results obtained under present climate conditions evidenced interactions between intensification effects and soil and climate conditions. We show that biophysical impacts on radiative forcing potential, through albedo increase and convective fluxes of heat and water, are in the same order of magnitude than changes in the biogeochemical cycle of carbon. Drought affects dramatically the net carbon and water balances of forest stands independent of management and age. However, the effects of successive management operations (ploughing, vegetation burial, thinning) overtook climate impacts and make the young stands and intensive alternatives more independent and resilient to climate change impacts. The model applications to the analysis of future climate scenarios allowed to attributing the role of management alternatives, soil conditions and climate and their interactions. For intensively managed forests, the frequency of soil preparation operations, the management

  11. Water balance monitoring for two bioretention gardens in Omaha, Nebraska, 2011–14

    USGS Publications Warehouse

    Strauch, Kellan R.; Rus, David L.; Holm, Kent E.

    2016-01-01

    Bioretention gardens are used to help mitigate stormwater runoff in urban settings in an attempt to restore the hydrologic response of the developed land to a natural predevelopment response in which more water is infiltrated rather than routed directly to urban drainage networks. To better understand the performance of bioretention gardens in facilitating infiltration of stormwater in eastern Nebraska, the U.S. Geological Survey, in cooperation with the Douglas County Environmental Services and the Nebraska Environmental Trust, assessed the water balance of two bioretention gardens located in Omaha, Nebraska by monitoring the amount of stormwater entering and leaving the gardens. One garden is on the Douglas County Health Center campus, and the other garden is on the property of the Eastern Nebraska Office on Aging.For the Douglas County Health Center, bioretention garden performance was evaluated on the basis of volume reduction by comparing total inflow volume to total outflow volume. The bioretention garden reduced inflow volumes from a minimum of 33 percent to 100 percent (a complete reduction in inflow volume) depending on the size of the event. Although variable, the percent reduction of the inflow volume tended to decrease with increasing total event rainfall. To assess how well the garden reduces stormwater peak inflow rates, peak inflows were plotted against peak outflows measured at the bioretention garden. Only 39 of the 255 events had any overflow, indicating 100 percent peak reduction in the other events. Of those 39 events having overflow, the mean peak reduction was 63 percent.No overflow events were recorded at the bioretention garden at the Eastern Nebraska Office on Aging; therefore, data were not available for an event-based overflow analysis.Monitoring period summary of the water balance at both bio-retention gardens indicates that most of the stormwater in the bioretention gardens is stored in the subsurface.Evapotranspiration was attributed

  12. Magnetic Field Structure of Pressure Balanced Structures from Ulysses High Latitudes Observations

    NASA Technical Reports Server (NTRS)

    Yamauchi, Y.; Suess, S. T.; Sakurai, T.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Ulysses observations showed that pressure balance structures (PBSs) are a common feature in the high-latitude solar winds near the solar minimum. On the other hand, coronal plumes are common in polar coronal holes near the solar minimum. It is therefore considered that the PBSs would be remnants of plumes. Several detailed studies of the PBSs have been made from Ulysses/SWOOPS observations, but study of their magnetic structures has not yet been done. The study of the magnetic structure is important because previous observations and theoretical models of plumes indicate that they are related to the network activity such as magnetic reconnection on the photosphere. We have investigated the magnetic structures of the PBSs with Ulysses magnetometer and SWOOPS data. We have found that magnetic reversals in radial magnetic field take place while the spacecraft passes through most of the PBSs These magnetic reversals have been interpreted as large amplitude Alfv/'enic fluctuations but our results suggest that Ulysses is also traversing current sheets of plasmoids associated with network activity at the base of plumes.

  13. Extraterrestrial Virtual Field Experience: Water at Meridiani

    NASA Astrophysics Data System (ADS)

    Duggan-Haas, D.; Million, C.; Sullivan, R. J., Jr.; Hayes, A. G., Jr.; Ross, R. M.; St Clair, M.

    2014-12-01

    The Spacecraft Planetary Imaging Facility (SPIF) at Cornell University, in collaboration with Million Concepts and the Paleontological Research Institute (PRI), has developed the Extraterrestrial Virtual Field Experience (EVFE), a web-based, game-like and inquiry-driven classroom activity targeted to middle school through undergraduate introductory Earth science classrooms. Students play the role of mission scientists for a NASA rover mission, tasked with targeting the rover's scientific instruments to investigate a specific scientific question about the landing site. As with the real mission, the student operators must optimize the efficient use of limited resources and time against the need to make observations to address working hypotheses. The activity uses only real--not artificial or simulated--mission data, and students are guided throughout by a "Mission Manager" who provides hints and advice about the scientific meaning of observations within the broader context of the mission objectives. The MER Opportunity EVFE is a pilot effort, the first of five EVFE modules planned a rate of one per year that will feature different NASA missions and scientific topics. The MER Opportunity EVFE has already been developed and focuses on the investigation of the history of water on Mars at the Meridiani landing site of the Opportunity rover. The module includes a teacher guide and is currently available to educators through the SPIF website.

  14. Using multi-component hydrochemical pattern for water balance calculations of intricate water resources in semi-arid regions - a case study in Wadi Al Arab, Jordan.

    NASA Astrophysics Data System (ADS)

    Siebert, Christian; Rödiger, Tino; Geyer, Stefan; Subah, Ali; Guttman, Yossi

    2013-04-01

    Groundwater harvesting in the semi-arid Wadi al Arab, located in the NW most corner of the Kingdom of Jordan, is supposed to be sustainable. However, since implementation of intense well fields, which take water from the Cretaceous A7/B2 aquifer, springs along the wadi course dried out and groundwater table dropped locally tremendous. To overcome the uncertainties in qualitatively and quantitatively characterising that water resource, a multi-component hydrochemical study was carried out within the SMART-project, which was also used to provide reliable boundary conditions to build up a transient numerical flow model. Wadi Al Arab represents a multi-aquifer system, with unknown interactions between the Cenozoic and Cretaceous aquifers. The exact identification and qualitatively characterization of the different groundwater bodies, the definition of their flow regimes and the recharge rate is a necessary step to calculate a reliable water balance and a rational policy of water management. Inter-aquifer flow prevents the benchmark treatment of the groundwater bodies and its detection by classical methods is an almost impossible task. In order to overcome these difficulties, the main known components of the multi-aquifer system were analysed for REY (REE+ Yttrium) abundance, major elements and for stable isotopes of water (δ18O and δD). The different waters in the area were than classified considering these parameters. This enabled identifying their respective replenishment areas and to elucidate the mixing processes controlled by structural features. This study shows that REY patterns are a powerful tool to decipher the lithology of the catchment area and the intricate patterns of flow paths of the aquifer systems. These information allow the correct definition of boundary conditions for a successful hydraulic modelling.

  15. Water balance of two earthen landfill caps in a semi-arid climate

    SciTech Connect

    Khire, M.V.; Benson, C.H.; Bosscher, P.J.

    1997-12-31

    Water balance data are presented that were obtained from two earthen cap test sections located in a semi-arid region. The test sections were constructed on a municipal solid waste landfill in East Wenatchee, Washington, USA. One test section represents a traditional resistive barrier, and is constructed with a compacted silty clay barrier 60 cm thick and a vegetated silty clay surface layer 15 cm thick. The other test section represents a capillary barrier and has a sand layer 75 cm thick overlain by a 15-cm-thick vegetated surface layer of silt. Extensive hydrological and meteorological data have been collected since November 1992. Unsaturated hydraulic properties of soils, hydrologic parameters, and vegetation have been extensively characterized. Results of the study show that capillary barriers can be effective caps in semi-arid and arid regions. They are also cheaper to construct and can perform better than traditional resistive barriers.

  16. Thermodynamic Basis of Budyko Curve for Annual Water Balance: Proportionality Hypothesis and Maximum Entropy Production

    NASA Astrophysics Data System (ADS)

    Wang, Dingbao; Zhao, Jianshi; Tang, Yin; Sivapalan, Murugesu

    2015-04-01

    Recently, Wang and Tang [2014] demonstrated that the validity of the Proportionality Hypothesis extends to the partitioning of precipitation into runoff and evaporation at the annual time scale as well, and that the Budyko Curve could then be seen as the straightforward outcome of the application of the Proportionality Hypothesis to estimate mean annual water balance. In this talk, we go further and demonstrate that the Proportionality Hypothesis itself can be seen as a result of the application of the thermodynamic principle of Maximum Entropy Production (MEP), provided that the conductance coefficients assumed for evaporation and runoff are linearly proportional to their corresponding potential values. In this way, on the basis of this common hydrological assumption, we demonstrate a possible physical (thermodynamic) basis for the Proportionality Hypothesis, and consequently for the Budyko Curve.

  17. Modelling field scale water partitioning using on-site observations in sub-Saharan rainfed agriculture

    NASA Astrophysics Data System (ADS)

    Makurira, H.; Savenije, H. H. G.; Uhlenbrook, S.

    2009-08-01

    Smallholder rainfed farming systems generally realise sub-optimal crop yields which are largely attributed to dry spell occurrences during crop growth stages. However, with improved farming practices, it seems possible to significantly increase yield levels even with little and highly variable rainfall. The presented results follow research conducted in the Makanya catchment in northern Tanzania where gross rainfall amounts to less than 400 mm/season which is insufficient to support staple food crops (e.g. maize). Alternative cultivation techniques such as runoff harvesting and in-field micro-storage structures are compared. These techniques aim to reduce soil and nutrient loss from the field but, more importantly, promote in-field infiltration and water retention. Water balance components have been observed in order to study water partitioning processes under different cultivation techniques. Based on rainfall, soil evaporation, transpiration, runoff and soil moisture measurements, a water balance model has been developed to simulate soil moisture variations over the growing season. It appears that about 50% of the diverted water leaves the root zone through deep percolation. Modelling shows that during the field trials the average productive transpiration flow ranged between 1.1-1.4 mm d-1 in the trial plots compared to 0.7-1.0 mm d-1 under traditional tillage practice. Productive transpiration processes accounted for 23-29% while losses to deep percolation accounted for 33-48% of the available water. Conclusions from the research are that the innovations tested are effective in enhancing soil moisture retention at field scale and that diversions allow crop growth moisture conditions to be attained with early rains. It is also concluded that there is more scope for efficient utilisation of the diverted runoff water if storage structures could be installed to regulate water flow to the root zone when required.

  18. Modelling the water balance of a precise weighable lysimeter for short time scales

    NASA Astrophysics Data System (ADS)

    Fank, Johann; Klammler, Gernot; Rock, Gerhard

    2015-04-01

    Precise knowledge of the water fluxes between the atmosphere and the soil-plant system and the percolation to the groundwater system is of great importance for understanding and modeling water, solute and energy transfer in the atmosphere-plant-soil-groundwater system. Weighable lysimeters yield the most precise and realistic measures for the change of stored water volume (ΔS), Precipitation (P) which can be rain, irrigation, snow and dewfall and evapotranspiration (ET) as the sum of soil evaporation, evaporation of intercepted water and transpiration. They avoid systematic errors of standard gauges and class-A pans. Lysimeters with controlled suction at the lower boundary allow estimation of capillary rise (C) and leachate (L) on short time scales. Precise weighable large scale (surface >= 1 m2) monolithic lysimeters avoiding oasis effects allow to solve the water balance equation (P - ET - L + C ± ΔS = 0) for a 3D-section of a natural atmosphere-plant-soil-system for a certain time period. Precision and accuracy of the lysimeter measurements depend not only on the precision of the weighing device but also on external conditions, which cannot be controlled or turned off. To separate the noise in measured data sets from signals the adaptive window and adaptive threshold (AWAT) filter (Peters et al., 2014) is used. The data set for the years 2010 and 2011 from the HYDRO-lysimeter (surface = 1 m2, depth = 1 m) in Wagna, Austria (Klammler and Fank, 2014) with a resolution of 0,01 mm for the lysimeter scale and of 0,001 mm for the leachate tank scale is used to evaluate the water balance. The mass of the lysimeter and the mass of the leachate tank is measured every two seconds. The measurements are stored as one minute arithmetic means. Based on calculations in a calibration period from January to May 2010 with different widths of moving window the wmax - Parameter for the AWAT filter was set to 41 minutes. A time series for the system mass ('upper boundary') of the

  19. Enhancing MQMAS of low-gamma nuclei by using a high B(1) field balanced probe circuit.

    PubMed

    Gan, Zhehong; Gor'kov, Peter L; Brey, William W; Sideris, Paul J; Grey, Clare P

    2009-09-01

    A balanced probe circuit is used to generate high B(1) magnetic field for sensitivity enhancement of multiple-quantum magic-angle spinning (MQMAS) experiment applied to low-gamma quadrupolar nuclei. Electrical balancing of the sample coil can cut the peak voltage by a half, therefore improving the power handling when generating a two-fold higher B(1) field. Experimental results, illustrated here with (25)Mg data for two layered double hydroxides, show that the MQMAS efficiency increases more than linearly with the B(1) field strength. The multiplicative enhancements from high B(0) and B(1) fields and an optimized MQMAS pulse sequence provide the critically needed sensitivity for acquiring MQMAS spectra of low-gamma quadrupolar nuclei such as (25)Mg at natural abundance. PMID:19595617

  20. Role of external magnetic field and current closure in the force balance mechanism of a magnetically stabilized plasma torch

    NASA Astrophysics Data System (ADS)

    G, Ravi; Goyal, Vidhi

    2012-10-01

    Experimental investigations on the role of applied external magnetic field and return current closure in the force balance mechanism of a plasma torch are reported. The plasma torch is of low power and has wall, gas and magnetic stabilization mechanisms incorporated in it. Gas flow is divided into two parts: axial-central and peripheral-shroud, applied magnetic field is axial and return current is co-axial. Results indicate that application of large external magnetic field gives rise to not only J x B force but also, coupled with gas flow, to a new drag-cum-centrifugal force that acts on the plasma arc root and column. The magnetic field also plays a role in the return current closure dynamics and thus in the overall force balance mechanism. This in turn affects the electro-thermal efficiency of the plasma torch. Detailed experimental results, analytical calculations and physical model representing the processes will be presented and discussed.

  1. Cold-water immersion alters muscle recruitment and balance of basketball players during vertical jump landing.

    PubMed

    Macedo, Christiane de Souza Guerino; Vicente, Rafael Chagas; Cesário, Mauricio Donini; Guirro, Rinaldo Roberto de Jesus

    2016-01-01

    The purpose of this study was to evaluate the effects of cold-water immersion on the electromyographic (EMG) response of the lower limb and balance during unipodal jump landing. The evaluation comprised 40 individuals (20 basketball players and 20 non-athletes). The EMG response in the lateral gastrocnemius, tibialis anterior, fibular longus, rectus femoris, hamstring and gluteus medius; amplitude and mean speed of the centre of pressure, flight time and ground reaction force (GRF) were analysed. All volunteers remained for 20 min with their ankle immersed in cold-water, and were re-evaluated immediately post and after 10, 20 and 30 min of reheating. The Shapiro-Wilk test, Friedman test and Dunn's post test (P < 0.05) were used. The EMG response values decreased for the lateral gastrocnemius, tibialis anterior, fibular longus and rectus femoris of both athletes and non-athletes (P < 0.05). The comparison between the groups showed that the EMG response was lower for the athletes. Lower jump flight time and GRF, greater amplitude and mean speed of centre of pressure were predominant in the athletes. Cold-water immersion decreased the EMG activity of the lower limb, flight time and GRF and increased the amplitude and mean speed of centre of pressure. PMID:26058795

  2. Liquid water on Mars - An energy balance climate model for CO2/H2O atmospheres

    NASA Technical Reports Server (NTRS)

    Hoffert, M. I.; Callegari, A. J.; Hsieh, C. T.; Ziegler, W.

    1981-01-01

    A simple climatic model is developed for a Mars atmosphere containing CO2 and sufficient liquid water to account for the observed hydrologic surface features by the existence of a CO2/H2O greenhouse effect. A latitude-resolved climate model originally devised for terrestrial climate studies is applied to Martian conditions, with the difference between absorbed solar flux and emitted long-wave flux to space per unit area attributed to the divergence of the meridional heat flux and the poleward heat flux assumed to equal the atmospheric eddy heat flux. The global mean energy balance is calculated as a function of atmospheric pressure to assess the CO2/H2O greenhouse liquid water hypothesis, and some latitude-resolved cases are examined in detail in order to clarify the role of atmospheric transport and temperature-albedo feedback. It is shown that the combined CO2/H2O greenhouse at plausible early surface pressures may account for climates hot enough to support a hydrological cycle and running water at present-day insolation and visible albedo levels.

  3. A worldwide analysis of spatiotemporal changes in water balance-based evapotranspiration from 1982 to 2009

    NASA Astrophysics Data System (ADS)

    Zeng, Zhenzhong; Wang, Tao; Zhou, Feng; Ciais, Philippe; Mao, Jiafu; Shi, Xiaoying; Piao, Shilong

    2014-02-01

    A satellite-based water balance method is developed to model global evapotranspiration (ET) through coupling a water balance (WB) model with a machine-learning algorithm (the model tree ensemble, MTE) (hereafter WB-MTE). The WB-MTE algorithm was firstly trained by combining monthly WB-estimated basin ET with the potential drivers (e.g., radiation, temperature, precipitation, wind speed, and vegetation index) across 95 large river basins (5824 basin-months) and then applied to establish global monthly ET maps at a spatial resolution of 0.5° from 1982 to 2009. The global land ET estimated from WB-MTE has an annual mean of 593 ± 17 mm for 1982-2009, with a spatial distribution consistent with previous studies in all latitudes but the tropics. The ET estimated by WB-MTE also shows significant linear trends in both annual and seasonal global ET during 1982-2009, though the trends seem to have stalled after 1998. Moreover, our study presents a striking difference from the previous ones primarily in the magnitude of ET estimates during the wet season particularly in the tropics, where ET is highly uncertain due to lack of direct measurements. This may be tied to their lack of proper consideration to solar radiation and/or the rainfall interception process. By contrast, in the dry season, our estimate of ET compares well with the previous ones, both for the mean state and the variability. If we are to reduce the uncertainties in estimating ET, these results emphasize the necessity of deploying more observations during the wet season, particularly in the tropics.

  4. A Worldwide Analysis of Spatiotemporal Changes in Water Balance-based Evapotranspiration from 1982 to 2009

    NASA Astrophysics Data System (ADS)

    Zeng, Z.; Wang, T.; Zhou, F.; Ciais, P.; Mao, J.; Shi, X.; Piao, S.

    2014-12-01

    A satellite-based water balance method is developed to model global evapotranspiration (ET) through coupling a water balance (WB) model with a machine-learning algorithm (the model tree ensemble, MTE) (hereafter WB-MTE). The WB-MTE algorithm was firstly trained by combining monthly WB-estimated basin ET with the potential drivers (e.g., radiation, temperature, precipitation, wind speed, and vegetation index) across 95 large river basins (5824 basin-months) and then applied to establish global monthly ET maps at a spatial resolution of 0.5° from 1982 to 2009. The global land ET estimated from WB-MTE has an annual mean of 593 ± 17 mm for 1982-2009, with a spatial distribution consistent with previous studies in all latitudes but the tropics. The ET estimated by WB-MTE also shows significant linear trends in both annual and seasonal global ET during 1982-2009, though the trends seem to have stalled after 1998. Moreover, our study presents a striking difference from the previous ones primarily in the magnitude of ET estimates during the wet season particularly in the tropics, where ET is highly uncertain due to lack of direct measurements. This may be tied to their lack of proper consideration to solar radiation and/or the rainfall interception process. By contrast, in the dry season, our estimate of ET compares well with the previous ones, both for the mean state and the variability. If we are to reduce the uncertainties in estimating ET, these results emphasize the necessity of deploying more observations during the wet season, particularly in the tropics.

  5. Space-Time Modeling of Climate Change Effects on the Water Balance of Southwestern Alberta

    NASA Astrophysics Data System (ADS)

    Mutulu, P.; Blais, J.

    2005-12-01

    Changes and variabilities in space and time characteristics of hydro-climatic processes play a major role in the water balance of a watershed. Formulating suitable spatio-temporal models for interactive behavior of such processes is crucial in understanding and investigating potential climate change effects on hydrology of a watershed. Historical climatic and hydrologic data are herein used to calibrate a conceptual stochastic monthly water balance for southwestern Alberta watersheds in Canada for the present day climate. The inputs to the model are monthly precipitation, evapotranspiration and temperature time series and the outputs are monthly soil moisture storages and streamflow. To account for vegetation influence on the precipitation-runoff transformation, a moisture index parameter based on the Jansen-Haise formulation and HDF-EOS data is incorporated into the hydrologic model. An adaptive technique is used to describe time evolution and uncertainties in the moisture index parameter. To simulate the effects of global warming due to the doubling of CO2, outputs from the Canadian Global Coupled Model 1 (CGCM1) are used to provide inputs that are downscaled to drive the hydrologic model. Spatial estimation of unknown data are performed using a modified Kriging approach combined with Canonical Correlation analysis. Preliminary results indicate that the formulated model is statistically adequate for estimating monthly streamflow at the 95% level. It is also shown that a temperature based approach can be used to estimate the evapotranspiration time series as an immediate process when data for the latter are either unavailable or insufficient. This result is attractive in the sense that only temperature and precipitation are needed to drive the hydrologic model. Finally, the sensitivity of moisture index and streamflow to potential climate changes is briefly discussed.

  6. A swinging stage to continuously level a platform balance for field use.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The "Swinging Stage" is a research tool designed to continuously level a portable platform balance situated in the bed of a pickup truck. Each time the vehicle is moved a platform balance must be leveled. This is time consuming and frustrating especially when the vehicle is on a variable terrain. ...

  7. Rainfall-Runoff and Water-Balance Models for Management of the Fena Valley Reservoir, Guam

    USGS Publications Warehouse

    Yeung, Chiu W.

    2005-01-01

    The U.S. Geological Survey's Precipitation-Runoff Modeling System (PRMS) and a generalized water-balance model were calibrated and verified for use in estimating future availability of water in the Fena Valley Reservoir in response to various combinations of water withdrawal rates and rainfall conditions. Application of PRMS provides a physically based method for estimating runoff from the Fena Valley Watershed during the annual dry season, which extends from January through May. Runoff estimates from the PRMS are used as input to the water-balance model to estimate change in water levels and storage in the reservoir. A previously published model was calibrated for the Maulap and Imong River watersheds using rainfall data collected outside of the watershed. That model was applied to the Almagosa River watershed by transferring calibrated parameters and coefficients because information on daily diversions at the Almagosa Springs upstream of the gaging station was not available at the time. Runoff from the ungaged land area was not modeled. For this study, the availability of Almagosa Springs diversion data allowed the calibration of PRMS for the Almagosa River watershed. Rainfall data collected at the Almagosa rain gage since 1992 also provided better estimates of rainfall distribution in the watershed. In addition, the discontinuation of pan-evaporation data collection in 1998 required a change in the evapotranspiration estimation method used in the PRMS model. These reasons prompted the update of the PRMS for the Fena Valley Watershed. Simulated runoff volume from the PRMS compared reasonably with measured values for gaging stations on Maulap, Almagosa, and Imong Rivers, tributaries to the Fena Valley Reservoir. On the basis of monthly runoff simulation for the dry seasons included in the entire simulation period (1992-2001), the total volume of runoff can be predicted within -3.66 percent at Maulap River, within 5.37 percent at Almagosa River, and within 10

  8. Developmental profiles in tick water balance with a focus on the new Rocky Mountain spotted fever vector, Rhipicephalus sanguineus.

    PubMed

    Yoder, J A; Benoit, J B; Rellinger, E J; Tank, J L

    2006-12-01

    Recent reports indicate that the common brown dog tick, or kennel tick, Rhipicephalus sanguineus (Latreille) (Acari: Ixodidae) is a competent vector of Rocky Mountain spotted fever in the U.S.A. This tick is of concern to public health because of its high frequency of contact, as it has a unique ability to thrive within human homes. To assess the moisture requirements necessary for survival, water balance characteristics were determined for each developmental stage, from egg to adult. This is the first time that water relations in ticks have been assessed throughout the complete lifecycle. Notably, R. sanguineus is differentially adapted for life in a dry environment, as characterized by a suppressed water loss rate distinctive for each stage that distinguishes it from other ticks. Analysis of its dehydration tolerance limit and percentage body water content provides no evidence to suggest that the various stages of this tick can function more effectively containing less water, indicating that this species is modified for water conservation, not desiccation hardiness. All stages, eggs excepted, absorb water vapour from the air and can drink free water to replenish water stores. Developmentally, a shift in water balance strategies occurs in the transition from the larva, where the emphasis is on water gain (water vapour absorption from drier air), to the adult, where the emphasis is on water retention (low water loss rate). These results on the xerophilic-nature of R. sanguineus identify overhydration as the primary water stress, indicating that this tick is less dependent upon a moisture-rich habitat for survival, which matches its preference for a dry environment. We suggest that the controlled, host-confined conditions of homes and kennels have played a key role in promoting the ubiquitous distribution of R. sanguineus by creating isolated arid environments that enable this tick to establish within regions that are unfavourable for maintaining water balance. PMID

  9. Assessment of the soil water balance by the combination of cosmic ray neutron sensing and eddy covariance technique in an irrigated citrus orchard (Marrakesh, Morocco)

    NASA Astrophysics Data System (ADS)

    Mroos, Katja; Baroni, Gabriele; Er-Raki, Salah; Francke, Till; Khabba, Said; Jarlan, Lionel; Hanich, Lahoucine; Oswald, Sascha E.

    2014-05-01

    Irrigation water requirement plays a crucial role in many agricultural areas and especially in arid and semi-arid landscapes. Improvements in the water management and the performance of the irrigation systems require a correct evaluation of the hydrological processes involved. However, some difficulties can arise due to the heterogeneity of the soil-plant system and of the irrigation scheme. To overcome these limitations, in this study, the soil water balance is analyzed by the combination of the Eddy Covariance technique (EC) and Cosmic Ray neutron Sensing (CRS). EC provides the measurement of the actual evapotranspiration over the area as it was presented in many field conditions. Moreover CRS showed to be a valuable approach to measure the root zone soil moisture integrated in a footprint of ~30 ha. In this way, the combination of the two methodologies should provide a better analysis of the soil water balance at field scale, as opposed to point observations, e.g. by TDR, evaporimeter and fluxmeter. Then, this could increase the capability to assess the irrigation efficiency and the agricultural water management. The study is conducted in a citrus orchard situated in a semi-arid region, 30 km southwest of Marrakesh (Morocco). The site is flat and planted with trees of same age growing in parallel rows with drip irrigation lines and application of fertilizer and pesticides. The original soil seems modified on the surface by the agricultural use, creating differences between trees, rows and lines. In addition, the drip irrigation creates also a spatial variability of the water flux distribution in the field, making this site an interesting area to test the methodology. Particular attention is given to the adaptation of the standard soil sampling campaign used for the calibration of the CRS and the introduction of a weighing function. Data were collected from June to December 2013, which corresponds to the high plant transpiration. Despite the intention of the

  10. Water balance analysis of a watershed dominated by Eucalyptus grandis hybrid plantations in Felixlandia (MG, Brazil)

    NASA Astrophysics Data System (ADS)

    Surian-Gamba, Otávio; Cristina-Tonello, Kelly; Garcia-Leite, Hélio; Taguas, Encarnación V.; Texeira-Dias, Herly C.

    2015-04-01

    Commercial eucalyptus plantations are commonly associated to excessive water use despite the fact that numerous studies have demonstrated significant differences among species and environmental systems. In fact, the analysis of its impact on water balance depending on specific environmental conditions is essential to guarantee its sustainability. The water balance of Eucalyptus grandis hybrid plantations in the Basin Creek of Riacho Fundo in Felixlândia, Minas Gerais (Brazil) is presented through a study of 2.6 years of measurements in a catchment of 719.9 ha. The objective of this study was to analyze the relationships among precipitation, interception and evapotranspiration of eucalyptus plantations, for evaluating the weight on flow and effective precipitation. A triangular weir with a set of level- and baro-logger were used for measuring flow. Rainfall was measured with 2 pluviometers and evaporation using two evapotranspirometers Soil Control, Model JR-200mm. For througfall, eight plots of 136.5 m² each were installed with twelve pluviometers. To estimate the stemflow, the empirical equation Et = - 0.060 + 0.053 (P) was used, where P is the precipitation. The effective precipitation was calculated by summing of the througfall value plus the stemflow. The losses by interception were obtained by the difference between precipitation and effective precipitation. The analysis was carried out on the monthly and annual scales. The results showed that the measured rainfall was close to the average for the region, reaching values close to 1200 mm. The interception of the eucalyptus plantation for the period was approximately 12% of the external precipitation. There were neither significant relationships between flow and evapotranspiration nor between flow and effective precipitation, which shows the complexity of water components at the catchment scale. This is likely associated to the delay effect of the subsurface fl