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.

  2. 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...

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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...

  11. 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.

  12. Predicting water-to-cyclohexane partitioning of the SAMPL5 molecules using dielectric balancing of force fields

    NASA Astrophysics Data System (ADS)

    Paranahewage, S. Shanaka; Gierhart, Cassidy S.; Fennell, Christopher J.

    2016-11-01

    Alchemical transformation of solutes using classical fixed-charge force fields is a popular strategy for assessing the free energy of transfer in different environments. Accurate estimations of transfer between phases with significantly different polarities can be difficult because of the static nature of the force fields. Here, we report on an application of such calculations in the SAMPL5 experiment that also involves an effort in balancing solute and solvent interactions via their expected static dielectric constants. This strategy performs well with respect to predictive accuracy and correlation with unknown experimental values. We follow this by performing a series of retrospective investigations which highlight the potential importance of proper balancing in these systems, and we use a null hypothesis analysis to explore potential biases in the comparisons with experiment. The collective findings indicate that considerations of force field compatibility through dielectric behavior is a potential strategy for future improvements in transfer processes between disparate environments.

  13. 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.

  14. Water balance dynamics in the Nile Basin

    USGS Publications Warehouse

    Senay, Gabriel B.; Asante, Kwabena; Artan, Guleid A.

    2009-01-01

    Understanding the temporal and spatial dynamics of key water balance components of the Nile River will provide important information for the management of its water resources. This study used satellite-derived rainfall and other key weather variables derived from the Global Data Assimilation System to estimate and map the distribution of rainfall, actual evapotranspiration (ETa), and runoff. Daily water balance components were modelled in a grid-cell environment at 0·1 degree (∼10 km) spatial resolution for 7 years from 2001 through 2007. Annual maps of the key water balance components and derived variables such as runoff and ETa as a percent of rainfall were produced. Generally, the spatial patterns of rainfall and ETa indicate high values in the upstream watersheds (Uganda, southern Sudan, and southwestern Ethiopia) and low values in the downstream watersheds. However, runoff as a percent of rainfall is much higher in the Ethiopian highlands around the Blue Nile subwatershed. The analysis also showed the possible impact of land degradation in the Ethiopian highlands in reducing ETa magnitudes despite the availability of sufficient rainfall. Although the model estimates require field validation for the different subwatersheds, the runoff volume estimate for the Blue Nile subwatershed is within 7·0% of a figure reported from an earlier study. Further research is required for a thorough validation of the results and their integration with ecohydrologic models for better management of water and land resources in the various Nile Basin ecosystems.

  15. 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.

  16. Quantitative analysis of water use of forests in comparison to agricultural fields in Flanders using time series techniques and the water balance model WAVE

    NASA Astrophysics Data System (ADS)

    Verstraeten, W. W.; Veroustraete, F.; Muys, B.; Feyen, J.

    2003-04-01

    It is assumed that evapotranspiration from forests is larger than that from any other vegetation type. In the literature, examples in conflict are found. The objective of this study is to compare the water use terms of forest stands with those of agricultural crops in Flanders by implementing calibrated and validated model parameters for the different vegetations types in the water balance model WAVE (Vanclooster et al., 1994, 1996) for a simulation period with a time horizon of 30 years (1971-2000). The data analysis of the time series of the different water use terms is carried out at two levels: (1) the analysis of each individual time series using autocorrelation detection, trend analysis (Mann-Kendall) and autoregressive models (AR, Durbin-Watson) and; (2) grouping of the time series according to the distinctive factor, being water use of forest stands and agricultural crops. Mixed General Linear Models and Profile Analysis are implemented. The actual vegetation transpiration, the actual soil and interception evaporation of the different tree and crop species are compared as well as the general agricultural crop and forest stand. From this study it can be concluded that different statistical methods suggest that forest in Flanders does consume more water than agricultural crops. The water use terms also differ for the two land-use types considered. Generally only a few trends and autocorrelations are detected, especially in the time series from agricultural crops.

  17. [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.

  18. Analyzing Hydrological Sustainability Through Water Balance

    NASA Astrophysics Data System (ADS)

    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.

  19. Operational water balance in irrigation districts

    NASA Astrophysics Data System (ADS)

    Sánchez, Raúl; Rodríguez-Sinobas, Leonor; Juana, Luis; Laguna, Francisco V.

    2014-05-01

    In pressure irrigation-water 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 validated in laboratory PRV performance model coupled with an irrigation district waterworks. 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 carried on. The effect of demand concentration peaks has been assessed.

  20. 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.

  1. 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.

  2. Human Water and Electrolyte Balance

    DTIC Science & Technology

    2006-04-01

    e.g., boxing, power lifting, wrestling ) athletes frequently dehydrate to compete in lower weight classes. Also, persons medicated with di- uretics may...water loss among fluid spaces as well as among different body organs during hy- pohydration. They thermally dehydrated rats by 10% of body weight , and...intracellular (41%) and extracellular (59%) spaces. Re- garding organ fluid loss , 40% came from muscle , 30% from skin, 14% from viscera, and 14% from

  3. Water balance for Crater Lake, Oregon

    USGS Publications Warehouse

    Nathenson, Manuel

    1992-01-01

    A water balance for Crater Lake, Oregon, is calculated using measured lake levels and precipitation data measured at Park Headquarters and at a gage on the North Rim. Total water supply to the lake from precipitation and inflow from the crater walls is found to be 224 cm/y over the area of the lake. The ratio between water supply to the lake and precipitation at Park Headquarters is calculated as 1.325. Using leakage determined by Phillips (1968) and Redmond (1990), evaporation from the lake is approximately 85 cm/y. Calculations show that water balances with precipitation data only from Park Headquarters are unable to accurately define the water-level variation, whereas the addition of yearly precipitation data from the North Rim reduces the average absolute deviation between calculated and modeled water levels by one half. Daily precipitation and water-level data are modeled assuming that precipitation is stored on the rim as snow during fall and winter and released uniformly during the spring and early summer. Daily data do not accurately define the water balance, but they suggest that direct precipitation on the lake is about 10 % higher than that measured at Park Headquarters and that about 17 % of the water supply is from inflow from the rim.

  4. 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

  5. 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.

  6. 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).

  7. 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

  8. Modelling the impacts of climate change on wheat yield and field water balance over the Murray-Darling Basin in Australia

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Wang, Enli; Liu, De Li

    2011-06-01

    The study used a modelling approach to assess the potential impacts of likely climate change and increase in CO2 concentration on the wheat growth and water balance in Murray-Darling Basin in Australia. Impacts of individual changes in temperature, rainfall or CO2 concentration as, well as the 2050 and 2070 climate change scenarios, were analysed. Along an E-W transect, wheat yield at western sites (warmer and drier) was simulated to be more sensitive to temperature increase than that at eastern sites; along the S-N transect, wheat yield at northern warmer sites was simulated to be more sensitive to temperature increase, within 1-3°C temperature increase. Along the E-W and S-N transects, wheat at drier sites would benefit more from elevated [CO2] than at wetter sites, but more sensitive to the decline in rainfall. The increase in temperature only did not have much impact on water balance. Elevated [CO2] increased the drainage in all the sites, whilst rainfall reduction decreased evapotranspiration, runoff and drainage, especially at drier sites. In 2050, wheat yield would increase by 1-10% under all climate change scenarios along the S-N transect, except for the northernmost site (Dalby). Along the E-W transect, the most obvious increase of wheat yields under all climate change scenarios occurred in cooler and wetter eastern sites (Yass and Young), with an average increase rate of 7%. The biggest loss occurred at the driest sites (Griffith and Swan Hill) under A1FI and B2 scenarios, ranging from -5% to -16%. In 2070, there would be an increased risk of yield loss in general, except for the cool and wet sites. Water use efficiency was simulated to increase at most of the study sites under all the climate change scenarios, except for the driest site. Yield variability would increase at drier sites (Ardlethan, Griffith and Swan Hill). Soil types would also impact on the response of wheat yield and water balance to future climate change.

  9. 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."

  10. Simulation of the soil water balance of an undeveloped prairie in west-central Florida

    USGS Publications Warehouse

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

    1996-01-01

    A one-dimensional numerical model was developed to simulate the soil water balance of a densely vegetated prairie site in west-central Florida. Transient simulations of the soil water balance were performed using field-measured soil and vegetation properties. Simulated and measured soil water content generally agreed to within 0.04; however, simulated water storage and recharge were sensitive to air-entry soil-water pressure potential and depth to the water table.

  11. 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.

  12. Arid site water balance: evapotranspiration modeling and measurements

    SciTech Connect

    Gee, G.W.; Kirkham, R.R.

    1984-09-01

    In order to evaluate the magnitude of radionuclide transport at an aird site, a field and modeling study was conducted to measure and predict water movement under vegetated and bare soil conditions. Significant quantities of water were found to move below the roo of a shallow-rooted grass-covered area during wet years at the Hanford site. The unsaturated water flow model, UNSAT-1D, was resonably successful in simulating the transient behavior of the water balance at this site. The effects of layered soils on water balance were demonstrated using the model. Models used to evaluate water balance in arid regions should not rely on annual averages and assume that all precipitation is removed by evapotranspiration. The potential for drainage at arid sites exists under conditions where shallow rooted plants grow on coarse textured soils. This condition was observed at our study site at Hanford. Neutron probe data collected on a cheatgrass community at the Hanford site during a wet year indicated that over 5 cm of water drained below the 3.5-m depth. The unsaturated water flow model, UNSAT-1D, predicted water drainage of about 5 cm (single layer, 10 months) and 3.5 cm (two layers, 12 months) for the same time period. Additional field measurements of hydraulic conductivity will likely improve the drainage estimate made by UNSAT-1D. Additional information describing cheatgrass growth and water use at the grass site could improve model predictions of sink terms and subsequent calculations of water storage within the rooting zone. In arid areas where the major part of the annual precipitation occurs during months with low average potential evapotranspiration and where soils are vegetated but are coarse textured and well drained, significant drainage can occur. 31 references, 18 figures, 1 table.

  13. 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...

  14. Reduction of Uncertainty in Water Mass Balances

    NASA Astrophysics Data System (ADS)

    Trask, J. C.; Fogg, G. E.

    2007-12-01

    Two novel approaches that reduce uncertainty in lake, watershed, and basin water balances are presented and applied in the Lake Tahoe basin. A novel residual redistribution technique reduces random error in water balance component estimates. This technique is well-grounded in standard statistical methods, and is simple, robust, and of broad general applicability. Reduction of random error in areal precipitation and streamflow estimates is validated using independent data. Remaining random error variance in areal precipitation estimates is markedly small. Reduction of random error in annual areal precipitation estimates resolves watershed 'memory' of precipitation from prior water-years (WY). The signal of precipitation from prior WY is often obscured in random error noise associated with established methods for estimating inter-annual variations in total annual areal precipitation. It is shown that the relationship of eastern Tahoe sub-basin annual streamflow to precipitation from prior WY can be inferred in the absence of gage data, using noise-filtered precipitation data and whole basin water yield data. Limited stream gage records from eastern Tahoe sub-basins confirm the inferred dependence on precipitation from prior WY, and thus that watershed moisture storage changes are significant to the water mass balance over time scales of several years. Such long time scales for storage change effects on streamflow are typically not accurately accounted for in watershed hydrology models. Inter-annual changes in watershed moisture storage are readily distinguishable from inter-annual variations in watershed ET. Application of a novel precipitation-decorrelation technique yields an estimate of Lake Tahoe mean annual evaporation with associated rigorously quantified uncertainty. This novel estimate agrees closely with several independent standard measurement-based evaporation estimates; and has uncertainty comparable to that of a high-quality energy balance approach. The

  15. Monthly Water Balance Model Hydrology Futures

    USGS Publications Warehouse

    Bock, Andy; Hay, Lauren E.; Markstrom, Steven; Atkinson, R. Dwight

    2016-01-01

    A monthly water balance model (MWBM) was driven with precipitation and temperature using a station-based dataset for current conditions (1950 to 2010) and selected statistically-downscaled general circulation models (GCMs) for current and future conditions (1950 to 2099) across the conterminous United States (CONUS) using hydrologic response units from the Geospatial Fabric for National Hydrologic Modeling (http://dx.doi.org/doi:10.5066/F7542KMD). Six MWBM output variables (actual evapotranspiration (AET), potential evapotranspiration (PET), runoff (RO), streamflow (STRM), soil moisture storage (SOIL), and snow water equivalent (SWE)) and the two MWBM input variables (atmospheric temperature (TAVE) and precipitation (PPT)) were summarized for hydrologic response units and aggregated at points of interest on a stream network. Results were then organized into the Monthly Water Balance Hydrology Futures database, an open-access database using netCDF format (http://cida-eros-mows1.er.usgs.gov/thredds/dodsC/nwb_pub/).  Methods used to calibrate and parameterize the MWBM are detailed in the Hydrology and Earth System Sciences (HESS)  paper "Parameter regionalization of a monthly water balance model for the conterminous United States" by Bock and others (2016).  See the discussion paper link in the "Related External Resources" section for access.  Supplemental data files related to the plots and data analysis in Bock and others (2016) can be found in the HESS-2015-325.zip folder in the "Attached Files" section.  Detailed information on the files and data can be found in the ReadMe.txt contained within the zipped folder. Recommended citation of discussion paper:Bock, A.R., Hay, L.E., McCabe, G.J., Markstrom, S.L., and Atkinson, R.D., 2016, Parameter regionalization of a monthly water balance model for the conterminous United States: Hydrology and Earth System Sciences, v. 20, 2861-2876, doi:10.5194/hess-20-2861-2016, 2016

  16. 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...

  17. 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...

  18. [Influence of weightlessness on water and electrolytes balance in body].

    PubMed

    Shen, X Y

    2000-02-01

    The balance of water and electrolytes plays an important role in enabling the human body to adapt to spaceflight. This paper introduced the research methods, and changes in water and electrolytes balance during and after space flight. The mechanism and the hazard of the disorder of water and electrolytes caused by weightlessness were discussed.

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Torsion-balance experiments and ultra-low-mass fields

    NASA Astrophysics Data System (ADS)

    Terrano, William

    2017-01-01

    Many of the solutions to outstanding problems in modern cosmology posit new, ultra-light fields. Unifying General Relativity and Quantum Mechanics appears to require new ultra-light fields at some level. Such fields are also invoked to drive inflation and dark energy. Ultra-light fields may also make up much or all of the dark matter density of the universe. Torsion pendulums, a technology that dates to the 18th century, remain one of the most sensitive experimental techniques to search for ultra-light, weakly interacting fields. I will explain how torsion balance experiments can search for beyond-the-standard-model fields using laboratory-based as well as galactic sources, and the important cosmological implications of these measurements. I will also describe a new experimental signature for which certain torsion balance geometries make very sensitive direct dark matter detectors over a broad range of interesting dark matter parameter space.

  8. Effects of Spatial Variability on Annual Average Water Balance

    NASA Astrophysics Data System (ADS)

    Milly, P. C. D.; Eagleson, P. S.

    1987-11-01

    Spatial variability of soil and vegetation causes spatial variability of the water balance. For an area in which the water balance is not affected by lateral water flow, the frequency distributions of storm surface runoff, evapotranspiration, and drainage to groundwater are derivable from distributions of soil hydraulic parameters by means of a point water balance model and local application of the vegetal equilibrium hypothesis. Means and variances of the components of the budget can be found by Monte Carlo simulation or by approximate local expansions. For a fixed set of mean soil parameters, soil spatial variability may induce significant changes in the areal mean water balance, particularly if storm surface runoff occurs. Variability of the pore size distribution index and permeability has a much larger effect than that of effective porosity on the means and variances of water balance variables. The importance of the pore size distribution index implies that the microscopic similarity assumption may underestimate the effects of soil spatial variability. In general, the presence of soil variability reduces the sensitivity of water balance to mean properties. For small levels of soil variability, there exists a unique equivalent homogeneous soil type that reproduces the budget components and the mean soil moisture saturation of an inhomogeneous area.

  9. 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.

  10. 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

  11. Components of the total water balance of an urban catchment.

    PubMed

    Mitchell, V Grace; McMahon, Thomas A; Mein, Russell G

    2003-12-01

    A daily model was used to quantify the components of the total urban water balance of the Curtin catchment, Canberra, Australia. For this catchment, the mean annual rainfall was found to be three times greater than imported potable water, and the sum of the output from the separate stormwater and wastewater systems exceeded the input of imported potable water by some 50%. Seasonal and annual variations in climate exert a very strong influence over the relative magnitude of the water balance components; this needs to be accounted for when assessing the potential for utilizing stormwater and wastewater within an urban catchment.

  12. Analysis of rainfall inputs and runoff under an A-frame oscillating rainfall simulator in a sugarcane field, Mackay region of Queensland: Matching measurement techniques to meet project water balance objectives

    NASA Astrophysics Data System (ADS)

    Fentie, Banti; Yu, Bofu; Ciesiolka, Cyril

    2010-05-01

    A total of 11 rainfall simulations were conducted on four different plots (ranging in area from 22.10 to 26.20 m2) in a sugarcane field (with slopes varying from 1-9% and a groundcover variability of bare - 100% cover) in the Mackay region of Northern Queensland. The objectives of these rainfall simulation experiments were many, but this paper discusses the measurement methodology and data quality of rainfall generated and subsequent runoff. Rainfall amount during the simulations was measured using two different sizes of rain gauges placed at different locations on the plot (left, centre, and right sides of the experimental plot). In addition to the 203mm ordinary rain gauges, three pluviometers (300mm) were placed along the centre of the plot to measure rainfall as a function of time during the simulation. The rainfall data from these three pluviometers was collected using dataloggers and processed using a computer program called Datalog, which converted the number of tips/minute into mm/h. Due to spatial variation of rainfall intensity applied to the surface as a function of height from the nozzles of the rainfall simulators, correction factors were determined using a computer program called ERFS developed for this purpose. The rainfall from each gauge and pluviometer was subsequently corrected for distance from the nozzles of the simulator and height of the gauge by multiplying it by the corresponding correction factor. The spatial distribution of rainfall amount during each simulation was determined by spatially interpolating measured amounts in order to ascertain the best estimate of applied rainfall and its energy. Runoff data during each simulation was collected using tipping buckets connected to data loggers. Runoff amounts were also manually collected at specified intervals as a back up, and for validation of those collected using tipping buckets in determining runoff rates for each simulation. Soil cores were taken for determining soil moisture balances

  13. Soil water balance scenario studies using predicted soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Nemes, A.; Wösten, J. H. M.; Bouma, J.; Várallyay, G.

    2006-03-01

    Pedotransfer functions (PTFs) have become a topic drawing increasing interest within the field of soil and environmental research because they can provide important soil physical data at relatively low cost. Few studies, however, explore which contributions PTFs can make to land-use planning, in terms of examining the expected outcome of certain changes in soil and water management practices. This paper describes three scenario studies that show some aspects of how PTFs may help improve decision making about land management practices. We use an exploratory research approach using simulation modelling to explore the potential effect of alternative solutions in land management. We: (i) evaluate benefits and risks when irrigating a field, and the impact of soil heterogeneity; (ii) examine which changes can be expected (in terms of soil water balance and supply) if organic matter content is changed as a result of an alternative management system; (iii) evaluate the risk of leaching to deeper horizons in some soils of Hungary. Using this research approach, quantitative answers are provided to what if? type questions, allowing the distinction of trends and potential problems, which may contribute to the development of sustainable management systems.

  14. Water balance in the playa-lakes of an arid environment, Monegros, NE Spain

    NASA Astrophysics Data System (ADS)

    Castañeda, Carmen; García-Vera, Miguel Ángel

    2008-02-01

    The playa-lakes of the Monegros desert in north-east Spain are saline wetlands in an arid environment, a rare phenomenon in Europe. These extremely valuable habitats are threatened by changes associated with agricultural expansion and incorporation of new irrigated areas. An understanding of the present hydrologic regime will enable changes to be identified, particularly those brought about by flooding and pollution caused by irrigation surplus. This study sets out to show the results of applying a daily water balance in three selected playa-lakes. The balance was in two parts and consisted of: (1) the average balance for all the endorheic basin using the BALAN_11 program, and (2) the water balance in some playa-lakes, applying discharge flows obtained from the previous balance. The resulting volumes of water were converted to water depths and contrasted with reference volumes taken from field and Landsat images. The model was calibrated by applying various hypotheses of function which enabled the results to be adjusted. The proposed balance is an acceptable reproduction of field water measurements during this period, and underlines the consistency of the conceptual model. The methodology used is appropriate for understanding the playa-lakes function and for monitoring them for conservation purposes.

  15. Water balance changes across environmental gradients in Sweden.

    NASA Astrophysics Data System (ADS)

    van der Velde, Y.; Lyon, S. W.; Vercauteren, N.; Destouni, G.

    2012-04-01

    Climate change, land use change and an increasing use of water for irrigation, industry, hydro power and consumption alter the water balance of many catchments. Such changes affect the water availability for ecosystems and humans but also affect hydrological conditions in downstream lakes and coastal zones. In the Baltic Sea region, for example, an increase in precipitation in Northern Sweden may reduce sea water salinity, while increasing evapotranspiration in the South, which is dominated by agriculture, may reduce nutrient leaching. Both changes will affect the Baltic Sea ecosystem. It thus is important to identify, for each region in Sweden, the dominant drivers for change to understand and anticipate future hydrological conditions in the Baltic Sea. In this study we have analyzed long term changes in the water balance for 250 catchments in Sweden. By quantifying the spatial correlation of these changes between catchments we were able to constrain measurement uncertainty in precipitation, discharge and catchment area. This allowed us to create reliable regional estimates of changes in precipitation, discharge and evapotranspiration for the period 1960-2010. The Bodyko framework was used to translate these water balance changes to water use efficiency trajectories across environmental gradients (latitude, elevation, agriculture and population). These trajectories in Bodyko-space help to identify the contributions of climate change and changes in water use efficiency to observed changes in the water balance. We show that within Sweden distinctly different trajectories of hydrological change occur and that these differences should be accounted for in climate change adaptation strategies.

  16. The water balance of a sub-Arctic town

    NASA Astrophysics Data System (ADS)

    Semádeni-Davies, Annette F.; Bengtsson, Lars

    1999-09-01

    Urban water balances differ from their rural counterparts due to extreme spatial heterogeneity, water imported from outside catchment boundaries and changed flow paths (e.g., drainage pipes and impervious surfaces). Urban catchments are characterized by increased peak discharges and fast response times, each contributing to specific environmental problems. The water balances of towns in the northern high latitudes are further complicated by snow which represents an energy dependent seasonal water store.This paper investigates the monthly water balance of Luleå (June 1992 to June 1996), a Swedish town of 71 000 inhabitants 100 km south of the Arctic Circle. The town has snow cover for five to six months of the year and thaw is usually in late April. Data available included daily precipitation, temperature and inflow to the Uddebo waste water treatment plant; and monthly potential evapotranspiration, groundwater levels and water supply statistics.Of interest were the seasonal differences in runoff volumes and flow pathways to the waste water treatment plant and receiving waters. It was found that increased volumes of runoff, reduced concentration times and long duration led to flooding and high waste water loads at the treatment plant. The surface water component of sewage originates from direct flow into pipe inlets and infiltration into sewer pipes. Autumn and spring were found to be the periods of groundwater recharge, although frozen soil can limit water percolation.

  17. Tritium Based Water Balance Modelling In The Weser Catchment, Germany

    NASA Astrophysics Data System (ADS)

    Koeniger, P.; Krause, W.; Leibundgut, Ch.; Reisewitz, R.

    The Institute of Hydrology of the Freiburg University (IHF) in conjunction with the German Federal Institute of Hydrology (BfG) are to integrating tritium data for a water balance model. Tritium observations in precipitation and river water covering a period of 30 years are used to establish a tritium aided water balance for a 46.300 km2 area in Germany (Weser catchment). Environmental tritium in precipitation, that was mainly introduced into the water cycle by nuclear weapon testing in the 60s, and wastewater from nuclear power plants located in the catchment area are sources of the tritium input. The model is established in combination with a software routine (TRIBIL), which was developed for semi distributed water and tritium balance calculations. A mesoscale, physically based model approach with spatial classification of sub areas is used and will consider evaporation, transpiration, soil characteristics, vegetation and different runoff components. The modelling is performed in monthly time steps. Hydrological, meteorological and land use data are available from different German authorities. An outline of the project, model structure and input data as well as first results for the tributary river systems Fulda and Werra will be presented. Including the conser- vative tracer tritium into large scale modelling is a rather new approach. Feasibilities and possibilities will be tested within this project. Balancing of solutes in catchment studies can be improved and this approach can serve as an additional validation tool for water balance models.

  18. Water balance report for the Oak Ridge Y-12 Plant

    SciTech Connect

    1994-07-01

    The Y-12 Plant, which occupies approximately 800 acres, was built by the Army Corps of Engineers in 1943 as part of the Manhattan Project in Oak Ridge, Tennessee. Recently, Martin Marietta Energy Systems, who manages the Y-12 Plant, has been concerned with the effects of water consumption and losses at the plant facility, and the ability of ground water beneath the site to act as a source of water seepage into East Fork Poplar Creek or as a source of water infiltration into subsurface strata. This has prompted the need to perform a water balance study on the facility. Data regarding all uses of municipal water and sources of discharge from the plant were recorded and then water balance calculations were performed using a computer model developed in a multi-dimensional electronic spreadsheet. This report describes the results of this research and includes the flow data collected during the study.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Water-Energy balance in pressure irrigation systems

    NASA Astrophysics Data System (ADS)

    Sánchez, Raúl; Rodríguez-Sinobas, Leonor; Juana, Luis; Laguna, Francisco V.; Castañón, Guillermo; Gil, María; Benitez, Javier

    2013-04-01

    Modernization of irrigation schemes, generally understood as transformation of surface irrigation systems into pressure -sprinkler and trickle- irrigation systems, aims at, among others, improving irrigation efficiency and reduction of operation and maintenance efforts made by the irrigators. Automation techniques become easier after modernization, and operation management plays an important role in energy efficiency issues. Modern systems use to include elevated water reservoirs with enough capacity to irrigate during peak water demand period about 16 to 48 h. However, pressure irrigation systems, in contrast, carry a serious energy cost. Energy requirements depend on decisions taken on management strategies during the operation phase, which are conditioned by previous decisions taken on the design project of the different elements which compose the irrigation system. Most of the countries where irrigation activity is significant bear in mind that modernization irrigation must play a key role in the agricultural infrastructure policies. The objective of this study is to characterize and estimate the mean and variation of the energy consumed by common types of irrigation systems according to their management possibilities. Also is an objective to estimate the fraction of the water reservoirs available along the irrigation campaign for storing the energy from renewable sources during their availability periods. Simulation taking into account all elements comprising the irrigation system has been used to estimate the energy requirements of typical irrigation systems of several crop production systems. The simulation of various types of irrigation systems and management strategies, in the framework imposed by particular cropping systems, would help to develop criteria for improving the energy balance in relation to the irrigation water supply productivity and new opportunities in the renewable energy field.

  4. 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.

  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 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).

  7. 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…

  8. 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.

  9. 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

  10. 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…

  11. 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.

  12. 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.

  13. Momentum balance in the shallow water equations on bottom discontinuities

    NASA Astrophysics Data System (ADS)

    Valiani, A.; Caleffi, V.

    2017-02-01

    This work investigates the topical problem of balancing the shallow water equations over bottom steps of different heights. The current approaches in the literature are essentially based on mathematical analysis of the hyperbolic system of balance equations and take into account the relevant progresses in treating the non-conservative form of the governing system in the framework of path-conservative schemes. An important problem under debate is the correct position of the momentum balance closure when the bottom elevation is discontinuous. Cases of technical interest are systematically analysed, consisting of backward-facing steps and forward-facing steps, tackled supercritical and subcritical flows; critical (sonic) conditions are also analysed and discussed. The fundamental concept governing the problem and supported by the present computations is that the energy-conserving approach is the only approach that is consistent with the classical shallow water equations formulated with geometrical source terms and that the momentum balance is properly closed if a proper choice of a conventional depth on the bottom step is performed. The depth on the step is shown to be included between the depths just upstream and just downstream of the step. It is also shown that current choices (as given in the literature) of the depth on (or in front of) the step can lead to unphysical configurations, similar to some energy-increasing solutions.

  14. Atmospheric Water Balance and Variability in the MERRA-2 Reanalysis

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Robertson, Franklin R.; Takacs, Lawrence; Molod, Andrea; Mocko, David

    2017-01-01

    Closing and balancing Earths global water cycle remains a challenge for the climate community. Observations are limited in duration, global coverage, and frequency, and not all water cycle terms are adequately observed. Reanalyses aim to fill the gaps through the assimilation of as many atmospheric water vapor observations as possible. Former generations of reanalyses have demonstrated a number of systematic problems that have limited their use in climate studies, especially regarding low-frequency trends. This study characterizes the NASA Modern-Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) water cycle relative to contemporary reanalyses and observations. MERRA-2 includes measures intended to minimize the spurious global variations related to in homogeneity in the observational record. The global balance and cycling of water from ocean to land is presented, with special attention given to the water vapor analysis increment and the effects of the changing observing system. While some systematic regional biases can be identified,MERRA-2 produces temporally consistent time series of total column water and transport of water from ocean to land. However, the interannual variability of ocean evaporation is affected by the changing surface-wind-observing system, and precipitation variability is closely related to the evaporation. The surface energy budget is also strongly influenced by the interannual variability of the ocean evaporation. Furthermore, evaluating the relationship of temperature and water vapor indicates that the variations of water vapor with temperature are weaker in satellite data reanalyses, not just MERRA-2, than determined by observations, atmospheric models, or reanalyses without water vapor assimilation.

  15. 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.

  16. On fuel choice and water balance during migratory bird flights.

    PubMed

    Giulivi, Cecilia; Ramsey, Jon

    2015-01-01

    It has been proposed that water loss during flight in migratory birds under high evaporative conditions can be offset by the production of water through increased protein catabolism. Indeed, oxidation of protein may supply 7-times more water/kJ than fat. However, the lack of a relative increase in protein catabolism over that of fat during long flights indicates that processes other than water balance may be the primary drivers of protein catabolism during long and strenuous flights. These processes include the release of stress hormones (which increase both protein and fat catabolism) and protein catabolism triggered by increased oxidative damage to muscle proteins from reactive oxygen species produced by mitochondria. Protein catabolism is an important source of water for birds during migratory flight, but it remains to be determined if this process is directly regulated by hydration status.

  17. 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.

  18. 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.

  19. WATER CONTENT AND WATER BALANCE REGULATION IN FEMALE IXODID TICKS (ACARINA, IXODIDAE) DURING AND AFTER ENGORGEMENT,

    DTIC Science & Technology

    regulation is of value at the first stage only. In engorged females the maintenance of water balance is based on the decreased integument permeability and this peculiarity develops during the feeding period. (Author)

  20. 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

  1. 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

  2. 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

  3. 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%.

  4. 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

  5. Water balance comparison between a dry and a wet landfill — a full-scale experiment

    NASA Astrophysics Data System (ADS)

    Yuen, S. T. S.; Wang, Q. J.; Styles, J. R.; McMahon, T. A.

    2001-09-01

    This paper describes a water balance study conducted in a full-scale experimental municipal solid waste landfill in Melbourne, Australia. The investigation identified the significance of various hydrological components of a 'dry' landfill (represented by half of the experimental cell as a control section) and a 'wet' landfill (represented by other half of the cell allowing leachate recirculation and working as a bioreactor). The information obtained is important and useful in terms of leachate management for both dry and wet cell operations, especially for landfills located in a similar climate region. The study also determined the in situ field capacity of the waste and compared it to published data. The implication of using this field capacity value in water balance study is discussed.

  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. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Degradation of isoxaflutole (balance) herbicide by hypochlorite in tap water.

    PubMed

    Lin, Chung-Ho; Lerch, Robert N; Garrett, Harold E; George, Milon F

    2003-12-31

    Chlorine has been widely employed for the disinfection of drinking water. Additionally, it has the capacity to oxidize many organic compounds in water. Isoxaflutole (Balance; IXF) belongs to a new class of isoxazole herbicides. Isoxaflutole has a very short soil half-life and rapidly degrades to a stable and phytotoxic metabolite, diketonitrile (DKN). Further degradation of DKN produces a nonbiologically active benzoic acid (BA) metabolite. In experiments using high-performance liquid chromatography-UV spectroscopy (HPLC-UV) and HPLC tandem mass spectrometry (HPLC-MS/MS), DKN was found to rapidly react with hypochlorite in tap water, yielding the BA metabolite as the major end product. One milligram per liter (19 microM) of hypochlorite residue in tap water was able to completely oxidize up to 1600 microg/L (4.45 micromol/L) of DKN. In tap water, the disappearance of IXF was much more rapid than in DI water. As soon as the IXF is hydrolyzed to DKN, the DKN quickly reacts with the OCl(-) to form nonphytotoxic BA. As a result, the herbicide solutions prepared with tap water at 500 microg/L will no longer possess any herbicidal activity after 48 h of storage. However, in agronomic settings, highly concentrated tank solutions (600-800 mg/L) may be prepared with tap water since the conversion of IXF to BA would represent <5% of the herbicide; therefore, any impact on the herbicide efficacy would be negligible. Results of this study show that current chlorination disinfection protocols in municipal water systems would completely eliminate the phytotoxic form of this new herbicide, DKN, from drinking water supplies; yet, farmers can use chlorinated tap water without significant loss of efficacy.

  13. 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

  14. 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

  15. The Great Lakes Water Balance: Data availability and annotated bibliography of selected references

    USGS Publications Warehouse

    Neff, Brian P.; Killian, Jason R.

    2003-01-01

    Water balance calculations for the Great Lakes have been made for several decades and are a key component of Great Lakes water management. Despite the importance of the water balance, little has been done to inventory and describe the data available for use in water balance calculations. This report provides a catalog and brief description of major datasets that are used to calculate the Great Lakes water balance. Several additional datasets are identified that could be used to calculate parts of the water balance but currently are not being used. Individual offices and web pages that are useful for attaining these datasets are included. Four specific data gaps are also identified. An annotated bibliography of important publications dealing with the Great Lakes water balance is included. The findings of this investigation permit resource managers and scientists to access data more easily, assess shortcomings of current datasets, and identify which data are not currently being utilized in water balance calculations.

  16. Water balance trumps ion balance for early marine survival of juvenile pink salmon (Oncorhynchus gorbuscha).

    PubMed

    Sackville, M; Wilson, J M; Farrell, A P; Brauner, C J

    2012-08-01

    Smolting salmonids typically require weeks to months of physiological preparation in freshwater (FW) before entering seawater (SW). Remarkably, pink salmon (Oncorhynchus gorbuscha) enter SW directly following yolk absorption and gravel emergence at a size of 0.2 g. To survive this exceptional SW migration, pink salmon were hypothesized to develop hypo-osmoregulatory abilities prior to yolk absorption and emergence. To test this, alevins (pre-yolk absorption) and fry (post-yolk absorption) were transferred from FW in darkness to SW under simulated natural photoperiod (SNP). Ionoregulatory status was assessed at 0, 1 and 5 days post-transfer. SW alevins showed no evidence of hypo-osmoregulation, marked by significant water loss and no increase in gill Na⁺/K⁺-ATPase (NKA) activity or Na⁺:K⁺:2Cl⁻ cotransporter (NKCC) immunoreactive (IR) cell frequency. Conversely, fry maintained water balance, upregulated gill NKA activity by 50 %, increased the NKA α1b/α1a mRNA expression ratio by sixfold and increased NKCC IR cell frequency. We also provide the first evidence of photoperiod-triggered smoltification in pink salmon, as fry exposed to SNP in FW exhibited preparatory changes in gill NKA activity and α1 subunit expression similar to fry exposed to SNP in SW. Interestingly, fry incurred larger increases in whole body Na⁺ than alevins following both SW and FW + SNP exposure (40 and 20 % in fry vs. 0 % in alevins). The ability to incur and tolerate large ion loads may underlie a novel mechanism for maintaining water balance in SW prior to completing hypo-osmoregulatory development. We propose that pink salmon represent a new form of anadromy termed "precocious anadromy".

  17. A metabolism perspective on alternative urban water servicing options using water mass balance.

    PubMed

    Farooqui, Tauheed A; Renouf, Marguerite A; Kenway, Steven J

    2016-12-01

    Urban areas will need to pursue new water servicing options to ensure local supply security. Decisions about how best to employ them are not straightforward due to multiple considerations and the potential for problem shifting among them. We hypothesise that urban water metabolism evaluation based a water mass balance can help address this, and explore the utility of this perspective and the new insights it provides about water servicing options. Using a water mass balance evaluation framework, which considers direct urban water flows (both 'natural' hydrological and 'anthropogenic' flows), as well as water-related energy, we evaluated how the use of alternative water sources (stormwater/rainwater harvesting, wastewater/greywater recycling) at different scales influences the 'local water metabolism' of a case study urban development. New indicators were devised to represent the water-related 'resource efficiency' and 'hydrological performance' of the urban area. The new insights gained were the extent to which alternative water supplies influence the water efficiency and hydrological performance of the urban area, and the potential energy trade-offs. The novel contribution is the development of new indicators of urban water resource performance that bring together considerations of both the 'anthropogenic' and 'natural' water cycles, and the interactions between them. These are used for the first time to test alternative water servicing scenarios, and to provide a new perspective to complement broader sustainability assessments of urban water.

  18. Assessing the urban water balance: the Urban Water Flow Model and its application in Cyprus.

    PubMed

    Charalambous, Katerina; Bruggeman, Adriana; Lange, Manfred A

    2012-01-01

    Modelling the urban water balance enables the understanding of the interactions of water within an urban area and allows for better management of water resources. However, few models today provide a comprehensive overview of all water sources and uses. The objective of the current paper was to develop a user-friendly tool that quantifies and visualizes all water flows, losses and inefficiencies in urban environments. The Urban Water Flow Model was implemented in a spreadsheet and includes a water-savings application that computes the contributions of user-selected saving options to the overall water balance. The model was applied to the coastal town of Limassol, Cyprus, for the hydrologic years 2003/04-2008/09. Data were collected from the different authorities and hydrologic equations and estimations were added to complete the balance. Average precipitation was 363 mm/yr, amounting to 25.4 × 10(6)m(3)/yr, more than double the annual potable water supply to the town. Surface runoff constituted 29.6% of all outflows, while evapotranspiration from impervious areas was 21.6%. Possible potable water savings for 2008/09 were estimated at 5.3 × 10(3) m(3), which is 50% of the total potable water provided to the area. This saving would also result in a 6% reduction of surface runoff.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  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. 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.

  8. Impact of climate forcing uncertainty and human water use on global and continental water balance components

    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

    2016-10-01

    The assessment of water balance components using global hydrological models is subject to climate forcing uncertainty as well as to an increasing intensity of human water use within the 20th century. The uncertainty of five state-of-the-art climate forcings and the resulting range of cell runoff that is simulated by the global hydrological model WaterGAP is presented. On the global land surface, about 62 % of precipitation evapotranspires, whereas 38 % discharges into oceans and inland sinks. During 1971-2000, evapotranspiration due to human water use amounted to almost 1 % of precipitation, while this anthropogenic water flow increased by a factor of approximately 5 between 1901 and 2010. Deviation of estimated global discharge from the ensemble mean due to climate forcing uncertainty is approximately 4 %. Precipitation uncertainty is the most important reason for the uncertainty of discharge and evapotranspiration, followed by shortwave downward radiation. At continental levels, deviations of water balance components due to uncertain climate forcing are higher, with the highest discharge deviations occurring for river discharge in Africa (-6 to 11 % from the ensemble mean). Uncertain climate forcings also affect the estimation of irrigation water use and thus the estimated human impact of river discharge. The uncertainty range of global irrigation water consumption amounts to approximately 50 % of the global sum of water consumption in the other water use sector.

  9. 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...

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Analysis of Poyang Lake water balance and its indication of river-lake interaction.

    PubMed

    Zhang, Zengxin; Huang, Yuhan; Xu, Chong-Yu; Chen, Xi; Moss, Elica M; Jin, Qiu; Bailey, Alisha M

    2016-01-01

    In recent years, water shortage is becoming one of the most serious problems in the Poyang Lake. In this paper, the long-term water balance items of the Poyang Lake have been analyzed to reveal the coupling effects of Three Gorges Dam (TGD) and droughts on the water balance of Poyang Lake. The results indicate that: (1) the water balance items of Poyang Lake vary greatly, e.g. lake precipitation and inflow decrease during the past several decades while evaporation and water consumption increase significantly; (2) the water balance of Poyang Lake has been affected by the operation of TGD. Negative lake water balance in recent years leads to a serious water shortage problem in the Poyang Lake. Moreover, the operation of TGD also changed the river-lake relationship in the lower Yangtze River basin; (3) the coupling effects of drought and TGD on the lake water balance has been analyzed by using composite analysis method and it can be found that the operation of TGD has significantly altered the lake water balance. But it is not the only factor that affects the lake water balance, and the droughts might cause their relations to be much more complicated.

  16. 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.

  17. Water balance of the Lepenci river basin, Kosova

    NASA Astrophysics Data System (ADS)

    Osmanaj, L.; Avdullahi, S.

    2009-04-01

    Republic of Kosova lines on the highlands (500-600 m above sea level) surrounded by the mountains reaching the altitude of more than 2000m. Lower mountains divide the highland plain into four watershed areas, from where waters flow to there different seas, namely to the Adriatic Sea, the Aegean Sea and the Black Sea. Kosova has four water basins, such as the Basin of river Drini i Bardhe, Ibri, Morava e Binqes and Lepenci. The Basin of river Lepenci is located in South-eastern part of Kosova with surface of 650 km2, belongs to Axios river basin discharging into Aegean Sea. The annual rainfall is 670-1.000 mm and specific runoff 8 - 20 l/s/km2. There are also steep mountains in this area. In this case study we have calculate the water balance of the river Lepenc Basin. The Basin of river Lepenc we have divided in to 3 catchments: of Nerodima river, and upper and lower part of river Lepenci. This basin is covered by three municipalities such as municipality of Ferizaj, Kaçanik and Shterpc. The data on precipitation are obtained from three metering stations, such as the metering station of Ferizaj, Kaçanik and Jazhnice. The obtained records are elaborated. For evapotranspiration measurement we have applied four methods: the method of BLANEY - CRIDDLE, radiation, SCHENDELE and Turk. In a basin of river Lepenci we have four stations for measuring the discharges and levels: in Ferizaj, and Kaçanik - Nerodime river and in Hani i Elezit - Lepenc river. The river basin Lepenc has two inflowing points, where are Lepenci river in the border with the FYR of Macedonia and Sazli village near Ferizaj. Key works: precipitation, evaporation, flow, river, discharges,

  18. Intercode Comparisons for Simulating Water Balance of Near-Surface Soils

    NASA Astrophysics Data System (ADS)

    Scanlon, B. R.; Christman, M.; Simunek, J.; Reedy, R. C.

    2001-12-01

    Advances in computer technology, improvements in codes, including computational efficiency and processes simulated, and availability of long-term field monitoring data allow long-term simulations of near-surface flow that is important for groundwater recharge, contaminant transport, and waste containment. A variety of codes are available to simulate the water balance of near-surface soils; however, information on intercode comparisons is limited. The purpose of this study was to compare the characteristics and performance of different codes, including HELP, HYDRUS-1D, SHAW, SoilCover, SWIM, UNSATH, and VS2DT to simulate the water balance of near-surface soils. Factors that differ among these codes include graphical user interfaces, user friendliness, dimensionality, upper and lower boundary conditions, hydraulic properties (Brooks and Corey, van Genuchten, others), and processes simulated (liquid flow, vapor flow, hysteresis). A highly instrumented, engineered cover for waste containment in the Chihuahuan Desert provided information on initial and boundary conditions for the simulations and data to validate the simulation results. Simulations were conducted for the period October 1997 through September 1998 when the site was nonvegetated. Simulation results from all codes reasonably approximated the field-measured water balance. The main difference between the different simulation results was in the partitioning of precipitation into evaporation and soil water storage. These differences can be attributed primarily to the time resolution of the meteorological input data (daily, hourly, or 15 min) and the assignment of fluxes during precipitation events. The intercode comparisons are being used to identify important attributes of codes to simulate infiltration into the shallow subsurface. Such information can be used to make recommendations for modifications of existing codes and/or development of new codes.

  19. Evaluating water conservation and reuse policies using a dynamic water balance model.

    PubMed

    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.

  20. Understanding Pathways of Water-Resource Development: An End-Member, Water- Balance Approach

    NASA Astrophysics Data System (ADS)

    Weiskel, P.

    2008-12-01

    Concern about the sustainability of human water-use practices is spreading rapidly throughout the world. Regional-scale depletion of aquifers and river systems, dessication of large lakes, and associated degradation of soil, water, and ecosystem quality are typical consequences of contemporary water-use patterns. To facilitate understanding of these patterns and their historical development, it is useful to apply a comprehensive approach to the terrestrial water balance that quantifies the magnitude of human components of the water balance (withdrawals, return flows, transfers) as well as natural components (precipitation, evapotranspiration, ground-water, and surface-water flows). We present such an approach and use it to define four end-member states, or water-use regimes, applicable to any bounded hydrologic system: (1) undeveloped; (2) depleted (withdrawal-dominated); (3) surcharged (return flow and import- dominated); and (4) churned (human-flow-dominated). The pathway by which a system evolves from an undeveloped state toward one or more of the developed end-members constitutes the hydrologic history of a system during its period of human influence. Graphical techniques are introduced to illustrate several hypothetical and real development pathways. The resulting plots help to shed light on the diverse-and in many cases unsustainable-ways in which humans interact with hydrologic systems.

  1. Mapping the water balance over a wide range of European catchments.

    NASA Astrophysics Data System (ADS)

    Pannemans, B.; Laguardia, G.

    2009-04-01

    Getting the water balance correct is one of the major problems of hydrological modeling: inputs (precipitation) and outputs (evaporation and runoff) should be in reasonable balance before calibration can even start. Often errors on the water balance can have a bigger influence on results than model calibration. Lisflood is a distributed hydrological model used in the European Flood Alert System and in the European Droughts Observatory of the European Commission's Joint Research Centre (JRC). It comprises a module for calculating PET; moreover, a major effort in preparing the static input for the model, such as land use, vegetation, Leaf Area Index, river networks maps, has been carried out in the last years. The challenge to use the same model over a wide region, covering the entire Europe makes it a good tool to explore the impact of different hydrological settings (Van der Knijff et al, 2008). As part of a new calibration exercise, we reran the model over Europe with standard calibration parameters for the period 1990-2007. The meteorological input was retrieved from the MARS database at JRC (about 6000 stations). We compared mean annual simulated discharge with observed discharge for over 400 catchments. Preliminary results show that the water balance is offset in most regions. In lowlands there is an excess in simulated runoff production, probably attributable to underestimated drainage to deeper groundwater and to underestimation of actual evapotranspiration. In most mountainous regions and in the middle-european massifs there is a shortage in runoff production, which is probably related to precipitation underestimation. Calibrating on parameters that increase evapotranspiration or infiltration to deeper groundwater layers could improve the results in the lowlands. Using other high-resolution data sets or improved interpolation techniques can solve only partly the problems related to the mountainous areas: we compared three precipitation sources and found that

  2. 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.

  3. 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.

  4. Carbon Balance and Water Relations of Sorghum Exposed to Salt and Water Stress 1

    PubMed Central

    Richardson, Steven G.; McCree, Keith J.

    1985-01-01

    The daily (24 hour) changes in carbon balance, water loss, and leaf area of whole sorghum plants (Sorghum bicolor L. Moench, cv BTX616) were measured under controlled environment conditions typical of warm, humid, sunny days. Plants were either (a) irrigated frequently with nutrient solution (osmotic potential −0.08 kilojoules per kilogram = −0.8 bar), (b) not irrigated for 15 days, (c) irrigated frequently with moderately saline nutrient (80 millimoles NaCl + 20 millimoles CaCl2·2H2O per kilogram water, osmotic potential −0.56 kilojoules per kilogram), or (d) preirrigated with saline nutrient and then not irrigated for 22 days. Under frequent irrigation, salt reduced leaf expansion and carbon gain, but water use efficiency was increased since the water loss rate was reduced more than the carbon gain. Water stress developed more slowly in the salinized plants and they were able to adjust osmotically by a greater amount. Leaf expansion and carbon gain continued down to lower leaf water potentials. Some additional metabolic cost associated with salt stress was detected, but under water stress this was balanced by the reduced cost of storing photosynthate rather than converting it to new biomass. Reirrigation produced a burst of respiration associated with renewed synthesis of biomass from stored photosynthate. It is concluded that although irrigation of sorghum with moderately saline water inhibits plant growth in comparison with irrigation with nonsaline water, it also inhibits water loss and allows a greater degree of osmotic adjustment, so that the plants are able to continue growing longer and reach lower leaf water potentials between irrigations. PMID:16664521

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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.

    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.

  10. 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…

  11. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 816.42 Section 816.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  12. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 816.42 Section 816.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  13. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 817.42 Section 817.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  14. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 817.42 Section 817.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 816.42 Section 816.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION 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, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 817.42 Section 817.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  17. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 817.42 Section 817.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 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

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 816.42 Section 816.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  19. 30 CFR 816.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 816.42 Section 816.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-SURFACE MINING ACTIVITIES § 816.42 Hydrologic balance: Water quality standards and...

  20. 30 CFR 817.42 - Hydrologic balance: Water quality standards and effluent limitations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Hydrologic balance: Water quality standards and effluent limitations. 817.42 Section 817.42 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND... STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.42 Hydrologic balance: Water quality standards and...

  1. Water balance at an arid site: a model validation study of bare soil evaluation

    SciTech Connect

    Jones, T.L.; Campbell, G.S.; Gee, G.W.

    1984-03-01

    This report contains results of model validation studies conducted by Pacific Northwest Laboratory (PNL) for the Department of Energy's (DOE) National Low Level Waste Management Program (NLLWMP). The model validation tests consisted of using unsaturated water flow models to simulate water balance experiments conducted at the Buried Waste Test Facility (BWTF) located at the Department of Energy's Hanford site, near Richland, Washington. The BWTF is a lysimeter facility designed to collect field data on long-term water balance and radionuclide tracer movement. It has been operated by PNL for the NLLWMP since 1978. An experimental test case, developed from data collected at the BWTF, was used to evaluate predictions from different water flow models. The major focus of the validation study was to evaluate how the use of different evaporation models affected the accuracy of predictions of evaporation, storage, and drainage made by the whole model. Four evaporation models were tested including two empirical models and two mechanistic models. The empirical models estimate actual evaporation from potential evaporation; the mechanistic models describe water vapor diffusion within the soil profile and between the soil and the atmosphere in terms of fundamental soil properties, and transport processes. The water flow models that included the diffusion-type evaporation submodels performed best overall. The empirical models performed poorly in their description of evaporation and profile water storage during summer months. The predictions of drainage were supported quite well by the experimental data. This indicates that the method used to estimate hydraulic conductivity needed for the Darcian submodel was adequate. This important result supports recommendations for these procedures that were made previously based on laboratory results.

  2. 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

  3. Estimation of groundwater pumping as closure to the water balance of a semi-arid, irrigated agricultural basin

    NASA Astrophysics Data System (ADS)

    Ruud, Nels; Harter, Thomas; Naugle, Alec

    2004-09-01

    Groundwater pumping is frequently the least measured water balance component in semi-arid basins with significant agricultural production. In this article, we develop a GIS-based water balance model for estimating basin-scale monthly and annual groundwater pumping and apply it to a 2300 km 2 semi-arid, irrigated agricultural area in the southern San Joaquin Valley, California. Both, annual groundwater storage changes and pumping are estimated as closure terms. The local hydrology is dominated by distributed surface water supplies, limited precipitation, and large crop water uses; whereas basin-scale runoff generation and groundwater-to-surface water discharges are negligible. Groundwater represents a terminal long-term storage reservoir with distributed inputs and outputs. To capture the spatio-temporal variability in water management and water use, the study area is delineated into 26 water service areas and 9611 individual fields or land units. The model computes conveyance seepage losses external to districts; seepage losses within districts; and net applied surface water of each district. For each land unit, the model calculates the applied water demand; its allotment of delivered surface water; the groundwater pumping required to meet the balance of its applied water demand; and aquifer recharge resulting from deep percolation of applied water and precipitation. These spatially distributed components are aggregated to the basin scale. Estimated annual groundwater storage changes compared well to those computed by the water-table fluctuation method over the 30-year study period, providing an independent verification of the consumptive use estimation. Pumping accounted for as much as 80% of the total applied water in 'Critical' water years and as little as 30% in 'Wet' years. Pumping estimates are most sensitive to estimation uncertainty of soil available water. They show little sensitivity to estimation errors in effective root depth, irrigation efficiencies

  4. Water, Ice, and Meteorological Measurements at South Cascade Glacier, Washington, Balance Years 2004 and 2005

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2007-01-01

    Winter snow accumulation and summer snow and ice ablation were measured at South Cascade Glacier, Washington, to estimate glacier mass-balance quantities for balance years 2004 and 2005. The North Cascade Range in the vicinity of South Cascade Glacier accumulated smaller than normal winter snowpacks during water years 2004 and 2005. Correspondingly, the balance years 2004 and 2005 maximum winter snow balances of South Cascade Glacier, 2.08 and 1.97 meters water equivalent, respectively, were smaller than the average of such balances since 1959. The 2004 glacier summer balance (-3.73 meters water equivalent) was the eleventh most negative during 1959 to 2005 and the 2005 glacier summer balance (-4.42 meters water equivalent) was the third most negative. The relatively small winter snow balances and unusually negative summer balances of 2004 and 2005 led to an overall loss of glacier mass. The 2004 and 2005 glacier net balances, -1.65 and -2.45 meters water equivalent, respectively, were the seventh and second most negative during 1953 to 2005. For both balance years, the accumulation area ratio was less than 0.05 and the equilibrium line altitude was higher than the glacier. The unusually negative 2004 and 2005 glacier net balances, combined with a negative balance previously reported for 2003, resulted in a cumulative 3-year net balance of -6.20 meters water equivalent. No equal or greater 3-year mass loss has occurred previously during the more than 4 decades of U.S. Geological Survey mass-balance measurements at South Cascade Glacier. Accompanying the glacier mass losses were retreat of the terminus and reduction of total glacier area. The terminus retreated at a rate of about 17 meters per year during balance year 2004 and 15 meters per year during balance year 2005. Glacier area near the end of balance years 2004 and 2005 was 1.82 and 1.75 square kilometers, respectively. Runoff from the basin containing the glacier and from an adjacent nonglacierized basin was

  5. 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.

  6. Meal consumption is ineffective at maintaining or correcting water balance in a desert lizard, Heloderma suspectum.

    PubMed

    Wright, Christian D; Jackson, Marin L; DeNardo, Dale F

    2013-04-15

    Many xeric organisms maintain water balance by relying on dietary and metabolic water rather than free water, even when free water may be available. For such organisms, hydric state may influence foraging decisions, since meal consumption is meeting both energy and water demands. To understand foraging decisions it is vital to understand the role of dietary water in maintaining water balance. We investigated whether meal consumption was sufficient to maintain water balance in captive Gila monsters (Heloderma suspectum) at varying levels of dehydration. Gila monsters could not maintain water balance over long time scales through meal consumption alone. Animals fed a single meal took no longer to dehydrate than controls when both groups were deprived of free water. Additionally, meal consumption imparts an acute short-term hydric cost regardless of hydration state. Meal consumption typically resulted in a significant elevation in osmolality at 6 h post-feeding, and plasma osmolality never fell below pre-feeding levels despite high water content (~70%) of meals. These results failed to support our hypothesis that dietary water is valuable to Gila monsters during seasonal drought. When considered in conjunction with previous research, these results demonstrate that Gila monsters, unlike many xeric species, are heavily reliant on seasonal rainfall and the resulting free-standing water to maintain water balance.

  7. 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.

  8. Circadian rhythm of water balance and aldosterone excretion in the whitebellied sunbird Nectarinia talatala.

    PubMed

    Fleming, P A; Gray, D A; Nicolson, S W

    2004-05-01

    Nectarivorous whitebellied sunbirds, Nectarinia talatala, demonstrate distinct circadian patterns in osmoregulatory parameters. We recorded intake of a 1 mol/l sucrose solution which enabled calculation of total water gain, and collected cloacal fluid for measurements of volume, osmolality and aldosterone concentration. These variables were assessed hourly over 12 h of photophase, and averaged over the 12-h scotophase period. Overnight, when sunbirds were in negative water balance, aldosterone concentrations and outputs were significantly higher than diurnal levels, reflecting a shut-down of cloacal fluid production. Early morning was marked by a high rate of osmotic excretion, disproportionate to water gain or cloacal fluid output, followed by steady intake and cloacal fluid output during the morning and early afternoon. Reduced water flux (decreased feeding and cloacal fluid output) during mid-afternoon was accompanied by a paradoxical decline in osmotic excretion, whilst a significant increase in the discrepancy between water intake and output was recorded as the birds effectively stored water before the scotophase. These patterns of intake and excretion may be informative in explaining drinking and foraging behaviour in the field.

  9. 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

  10. Particle and field stress balance within a planetary magnetosphere

    NASA Technical Reports Server (NTRS)

    Mauk, B. H.; Krimigis, S. M.; Lepping, R. P.

    1985-01-01

    A technique is developed for experimentally estimating the local tensor stresses within a planetary magnetic field configuration characterized by local spacecraft measurements. Key to the technique is the determination of the shapes of field lines using the symmetry properties of the system coupled with local and instantaneous measurements of the field line inclination angles. The technique is applied here to the inner and middle Saturnian magnetosphere using data returned by the Magnetic Field Experiment on the Voyager 1 spacecraft. It is concluded that the ring current has substantial radial structure, heretofore not shown. Outside about 13 R(s) the newly derived field stresses match remarkably well the funtional variation of the centrifugal corotation stresses of the cool particle population measured previously by the Plasma Science Experiment. Inside about 13 R(s) the key structure in the derived field stresses, a prominent local maximum, matches the approximate position of an apparent strong pressure gradient in the energetic particles characterized by the Low-Energy Charged Particle detectors.

  11. Vegetation Dynamics and Soil Water Balance Interactions in a Water-limited Mediterranean Ecosystem on Sardinia Under Climate Change Scenarios

    NASA Astrophysics Data System (ADS)

    Montaldo, N.; Albertson, J. D.

    2009-12-01

    Mediterranean ecosystems are commonly heterogeneous savanna-like ecosystems, with contrasting plant functional types (PFT) competing for the water use. At the same time the structure and function of the vegetation regulates the exchange of mass, energy and momentum across the biosphere-atmosphere interface, influencing strongly the soil water budget. Mediterranean regions suffer water scarcity produced in part by natural (e.g., climate variations) influences. For instance, in the Flumendosa basin water reservoir system, which plays a primary role in the water supply for much of southern Sardinia, the average annual input from stream discharge in the latter part of the 20th century was less than half the historic average rate. The precipitation over the Flumendosa basin has decreased, but not at such a drastic rate as the discharge, suggesting a marked non-linear response of discharge to precipitation changes. Indeed, precipitation decreased in winter months, which are crucial for reservoirs recharge through runoff. The IPCC models predicts a further increase of drought in the Mediterranean region, increasing the uncertainty on the future of the water resources system of these regions. Hence, there is the need to investigate the role of the PFT vegetation dynamics on the soil water budget of these ecosystems in the context of the climate change, and predict hydrologic variables for climate change scenarios. The case study is in the Flumendosa basin. The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and cork oaks, different shrubs and herbaceous species. An extensive field campaign started in May 2003. Six years of data are available now. Land-surface fluxes and CO2 fluxes are estimated by an eddy correlation technique based micrometeorological tower. Soil moisture profiles were also continuously estimated using water content reflectometers and gravimetric method, and periodically leaf area index (LAI) PFTs are

  12. Soil Water Balance and Vegetation Dynamics in a Water-limited Mediterranean Ecosystem on Sardinia under climate change scenarios

    NASA Astrophysics Data System (ADS)

    Montaldo, Nicola; Cortis, Clorinda; Albertson, John D.

    2010-05-01

    Mediterranean ecosystems are commonly heterogeneous savanna-like ecosystems, with contrasting plant functional types (PFT) competing for the water use. At the same time the structure and function of the vegetation regulates the exchange of mass, energy and momentum across the biosphere-atmosphere interface, influencing strongly the soil water budget. Mediterranean regions suffer water scarcity produced in part by natural (e.g., climate variations) influences. For instance, in the Flumendosa basin water reservoir system, which plays a primary role in the water supply for much of southern Sardinia, the average annual input from stream discharge in the latter part of the 20th century was less than half the historic average rate. The precipitation over the Flumendosa basin has decreased, but not at such a drastic rate as the discharge, suggesting a marked non-linear response of discharge to precipitation changes. Indeed, precipitation decreased in winter months, which are crucial for reservoirs recharge through runoff. The IPCC models predicts a further increase of drought in the Mediterranean region, increasing the uncertainty on the future of the water resources system of these regions. Hence, there is the need to investigate the role of the PFT vegetation dynamics on the soil water budget of these ecosystems in the context of the climate change, and predict hydrologic variables for climate change scenarios. The case study is in the Flumendosa basin. The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and cork oaks, different shrubs and herbaceous species. An extensive field campaign started in May 2003. More than six years of data of a micrometeorological tower are available now. Land-surface fluxes and CO2 fluxes are estimated by the eddy correlation technique based micrometeorological tower. Soil moisture profiles were also continuously estimated using water content reflectometers and gravimetric method, and

  13. Family planning field research projects: balancing internal against external validity.

    PubMed

    Fisher, A A; Carlaw, R W

    1983-01-01

    This report discusses the experience of a two-year family planning and maternal/child health project in Nepal. Although the project was planned as an experimental field research endeavor, a series of unanticipated events repeatedly compromised the internal validity of the project and forced design changes. While unexpected events are common in the history of most field projects, they present the research evaluator with the fundamental dilemma of trying to maintain a high degree of internal validity without sacrificing external validity. Rigid research designs with tight control over the introduction and measurement of experimental variables may serve to increase internal validity but they may also create an atypical and artificial situation that fails to mirror real field conditions and thus threatens external validity.

  14. Why are some STEM fields more gender balanced than others?

    PubMed

    Cheryan, Sapna; Ziegler, Sianna A; Montoya, Amanda K; Jiang, Lily

    2017-01-01

    Women obtain more than half of U.S. undergraduate degrees in biology, chemistry, and mathematics, yet they earn less than 20% of computer science, engineering, and physics undergraduate degrees (National Science Foundation, 2014a). Gender differences in interest in computer science, engineering, and physics appear even before college. Why are women represented in some science, technology, engineering, and mathematics (STEM) fields more than others? We conduct a critical review of the most commonly cited factors explaining gender disparities in STEM participation and investigate whether these factors explain differential gender participation across STEM fields. Math performance and discrimination influence who enters STEM, but there is little evidence to date that these factors explain why women's underrepresentation is relatively worse in some STEM fields. We introduce a model with three overarching factors to explain the larger gender gaps in participation in computer science, engineering, and physics than in biology, chemistry, and mathematics: (a) masculine cultures that signal a lower sense of belonging to women than men, (b) a lack of sufficient early experience with computer science, engineering, and physics, and (c) gender gaps in self-efficacy. Efforts to increase women's participation in computer science, engineering, and physics may benefit from changing masculine cultures and providing students with early experiences that signal equally to both girls and boys that they belong and can succeed in these fields. (PsycINFO Database Record

  15. 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.

  16. 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 ...

  17. Smarter Balanced "Tests of the Test" Successful: Field Test Provides Clear Path Forward

    ERIC Educational Resources Information Center

    Doorey, Nancy

    2014-01-01

    Between March and June of 2014, the Smarter Balanced Assessment Consortium conducted a field test of its new online assessment system. Thirteen participating states provided the results of surveys given to students and adults involved in the Field Test. Overall, more than 70% of test coordinators in each of seven states indicated that the Field…

  18. 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.

  19. Validation of a Simplified Energy Balance Model for Estimating Irrigated Cropland and Water use in Afghanistan

    NASA Astrophysics Data System (ADS)

    Budde, M. E.; Senay, G. B.; Verdin, J. P.; Rowland, J. D.

    2006-12-01

    A simplified energy balance model was developed to estimate cropped area and water use for two major irrigated areas in Afghanistan. The model utilized Moderate Resolution Imaging Spectroradiometer (MODIS) 1- km land surface temperature data to calculate a thermal-based evapotranspiration (ET) fraction. The fraction, based on temperature differences between "hot" and "cold" pixels in the study area, was used in conjunction with coarse resolution reference ET to estimate seasonal ET from irrigated lands for the 2000 2005 growing seasons. Irrigated areas in the Helmand River basin of southwestern Afghanistan and near the city of Kabul were analyzed. Model results compared well with field reports for irrigated watersheds which identified 2003 as a good year for crop production in Afghanistan. An advantage of this method over the crop water balance method is that it identifies irrigated areas directly and thus helps estimate total irrigated area and its spatial distribution in a given region. In an effort to validate the annual spatial variability of irrigated areas and associated water use, we utilized a combination of multi-date high resolution images acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument and the QuickBird satellite along with time series of MODIS Normalized Difference Vegetation Index (NDVI). Assessment of the spatial variability of irrigated lands in each of the study locations showed good agreement between the model output and these ancillary image data. In addition, time series NDVI provided seasonal profiles of vegetation productivity that could be compared to both the timing and magnitude of the modeled seasonal ET. We found that the timing of peak seasonal water use corresponded more with atmospheric demand than with timing of maximum NDVI.

  20. Role of soil water erosion on the organic carbon balance in a Mediterranean ecosystem.

    NASA Astrophysics Data System (ADS)

    Almagro, M.; Boix Fayos, C.; López, J.; Albaladejo, J.; Castillo, V.; Martínez-Mena, M.

    2009-04-01

    The soil organic carbon (SOC) pool represents a dynamic equilibrium of gains and losses. Conversion of forest ecosystems into croplands causes depletion of the SOC pool by as much as 60% in soils of temperate regions. Alterations in the size of the soil C pool at a specific location are determined by the relative changes in the inputs (aboveground and belowground net primary production) and outputs (decomposition of plant material and soil organic matter, root respiration and erosion) of C over yearly and longer time scales. The total global area of lands with a Mediterranean-type climate is about 2.75 million km2 (Rambal 2001). Coupled General Circulation Models (GCM) and ecophysiological models such as GOTILWA predict 1°C warming and 15-20% lower soil water availability for the next three decades in Mediterranean ecosystems as a result of smaller annual amounts of precipitation and also changes in rain distribution (IPPC, 2001; Sabaté et al., 2002), which may alter soil carbon dynamics. There is an ongoing debate about the role of soil erosion in the global carbon budget. Thus, while several authors consider that soil erosion has a strong impact on the global C cycle, others do not consider this component while assessing the global carbon budget. In the present study we evaluate the effect of soil erosion on the annual carbon balance under three representative land uses in a dry Mediterranean ecosystem (,a typical Mediterranean semiarid shrubland with scattered Aleppo pines, (ii) a rainfed olive grove, and (iii) an abandoned agricultural field) and determine the effectof land use changes on the carbon pools and fluxes. To address the role of land use change in controlling C fluxes, and thereby soil C sequestration rates, we measured aboveground and belowground net primary production, soil respiration and soil C loss via water erosion for two years, in each of the land use selected. The three selected areas showed a similar pattern in the annual carbon balance

  1. Water, ice, and meteorological measurements at South Cascade glacier, Washington, balance year 2003

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2005-01-01

    Winter snow accumulation and summer snow and ice ablation were measured at South Cascade Glacier, Washington, to estimate glacier mass-balance quantities for balance year 2003. The 2003 glacier-average maximum winter snow balance was 2.66 meters water equivalent, which was about equal to the average of such balances for the glacier since balance year 1959. The 2003 glacier summer balance (-4.76 meters water equivalent) was the most negative reported for the glacier, and the 2003 net balance (-2.10 meters water equivalent), was the second-most negative reported. The glacier 2003 annual (water year) balance was -1.89 meters water equivalent. The area of the glacier near the end of the balance year was 1.89 square kilometers, a decrease of 0.03 square kilometer from the previous year. The equilibrium-line altitude was higher than any part of the glacier; however, because snow remained along part of one side of the upper glacier, the accumulation-area ratio was 0.07. During September 13, 2002-September 13, 2003, the glacier terminus retreated at a rate of about 15 meters per year. Average speed of surface ice, computed using a series of vertical aerial photographs dating back to 2001, ranged from 2.2 to 21.8 meters per year. Runoff from the subbasin containing the glacier and from an adjacent non-glacierized basin was gaged during part of water year 2003. Air temperature, precipitation, atmospheric water-vapor pressure, wind speed, and incoming solar radiation were measured at selected locations on and near the glacier. Summer 2003 at the glacier was among the warmest for which data are available.

  2. 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.

  3. 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)

  4. 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.

  5. 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.

  6. Using expert elicitation to quantify catchment water balances and their uncertainties

    NASA Astrophysics Data System (ADS)

    Sebok, E.; Refsgaard, J. C.; Warmink, J. J.; Stisen, S.; Jensen, K. H.

    2016-07-01

    Expert elicitation with the participation of 35 experts was used to estimate a water balance for the nested Ahlergaarde and Holtum catchments in Western Denmark. Average annual values of precipitation, evapotranspiration, and surface runoff as well as subsurface outflow and recharge and their uncertainty were estimated in a multistep elicitation, where experts first gave their opinion on the probability distribution of their water balance component of interest, then the average annual values and uncertainty of water balance components and catchment-scale water balances were obtained by reaching consensus during group discussions. The obtained water balance errors for the 1055 km2 Ahlergaarde catchment and 120 km2 Holtum catchment were -5 and -62 mm/yr, respectively, with an uncertainty of 66 and 86 mm/yr, respectively. As an advantage of the expert elicitation, drawing on the intuitive experience and capabilities of experts to assess complex, site-specific problems, the contribution of independent sources of uncertainties to the total uncertainty was also evaluated similarly to the subsurface outflow component, which traditionally is estimated as the residual of the water balance.

  7. Measuring Air-water Interfacial Area for Soils Using the Mass Balance Surfactant-tracer Method

    PubMed Central

    Araujo, Juliana B.; Mainhagu, Jon; Brusseau, Mark L.

    2015-01-01

    There are several methods for conducting interfacial partitioning tracer tests to measure air-water interfacial area in porous media. One such approach is the mass balance surfactant tracer method. An advantage of the mass-balance method compared to other tracer-based methods is that a single test can produce multiple interfacial area measurements over a wide range of water saturations. The mass-balance method has been used to date only for glass beads or treated quartz sand. The purpose of this research is to investigate the effectiveness and implementability of the mass-balance method for application to more complex porous media. The results indicate that interfacial areas measured with the mass-balance method are consistent with values obtained with the miscible-displacement method. This includes results for a soil, for which solid-phase adsorption was a significant component of total tracer retention. PMID:25950136

  8. 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.

  9. 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

  10. 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

  11. 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).

  12. 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.

  13. 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.

  14. 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).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. Water balance of the Drini i Bardh River Basin, Kosova

    NASA Astrophysics Data System (ADS)

    Avdullahi, Sabri; Fejza, Isalm

    2010-05-01

    Republic of Kosova lines on the highlands (500-600 m above sea level) surrounded by the mountains reaching the altitude of more than 2000m. Lower mountains divide the highland plain into four watershed areas, from where waters flow to there different seas, namely to the Adriatic Sea, the Aegean Sea and the Black Sea. In the present day world, the problems of too much, too little or too polluted water are increasing at a rapid rate. These problems have become particularly severe for the developing countries, adversely affecting their agriculture, drinking water supply and sanitation. Water recourse management is no more just a challenger it is a declared crises. Water resources in Kosova are relatively small, total amount of water in our country is small around 1600 m3/inhabitant /year Drini i Bardhë river basin is in the western part of Kosova, it is the biggest river basin with surface of 4.289 km2. Drini i Bardhë discharges its water to Albania and finally to the Adriatic Sea. The area consist of several small stream from the mountains, water flows into tributaries and Drini i Bardhë River. In this river basin are based 12 hydrometric stations, 27 manual and 5 automatic rainfall measurements Drini i Bardhe River main basin contain a big number of sub basins from which the most important are: Lumëbardhi i Pejës (503.5km2), Lumëbardhi i Deçanit (278.3km2), Erenikut (515.5km2), Burimi (446.7km2), Klinës (439.0km2), Mirushes (334.5km2), Toplluges (498.2km2), Bistrica e Prizrenit (266.0 km2) and Plava (309 km2) fig 2. For evapotranspiration measurement we have applied four methods: the method of BLANEY - CRIDDLE, radiation, SCHENDELE and Turk. Protecting from pollution is a very important issue having in consideration that this river discharges its water and outside the territory. Hydrometeorology Institute of Kosova is in charge for monitoring of water quality. Key works: rainfall, flow, evaporation, river, evaporation coefficient (Ke) and feeding coefficient

  6. 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.

  7. 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.

  8. 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.

  9. Learning to Balance Assistance with Assessment: A Scholarship of Field Instruction

    ERIC Educational Resources Information Center

    Basmadjian, Kevin G.

    2011-01-01

    In this self-study, the author focuses on ways of embracing and managing a central dilemma of student teaching supervision: balancing assistance with assessment. Drawing on his practice as a field supervisor, the author chronicles conversations with student teachers over a 2-year period in the context of two distinct teacher education programs.…

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. Mass Balance Estimates of Louth Crater Water Ice and Climatic Implications

    NASA Astrophysics Data System (ADS)

    Bapst, J.; Byrne, S.

    2016-09-01

    We estimate the mass balance of the most-equatorward water ice mound on Mars, located in Louth crater (70N). It is expected to be ablating in the current climate. Our estimates include a wide range of atmospheric water abundances.

  17. Uncertainties due to soil data in Flood Risk Forecasts with the Water Balance Model LARSIM

    NASA Astrophysics Data System (ADS)

    Mitterer, Johannes

    2016-04-01

    Reliable flood forecasts with quantitative statements about contained uncertainties are essential for far reaching decisions in disaster management. In this paper uncertainties resulting from soil data are analysed for the in the German-speaking world widely used water balance model LARSIM and quantified as far as possible. At the beginning a structural and statistical analysis about the wittingly simple designed soil module is performed. It consists of a storage volume with four separate runoff components only defined by the storage size. Additionally, the model structure is examined with regard to effects of uncertain soil data using a soil map from the Bavarian State Institute for Forestry which already contains estimated minimum and maximum values for important soil parameters. For further analysis, two German catchments in Upper Franconia located at the White Main with a size of 250 km² each, covering a huge variety of soil types are used as case examples. Skeleton is identified as an important source of uncertainty in soil data comparing the quantifiable information of available soil maps and using field and laboratory analysis. Furthermore, surface runoff and fast interflow fluxes show up to be sensitive for peaks of flood events, whereas slow interflow and base flow fluxes have smaller and more long term effects on discharges and the water balance. A reduction of the soil storage basically leads to a more intensified reaction of discharges than an enlargement. The calculation of two extreme scenarios within the statistical analysis result in simulated gage measurements varying from -42 % till +218 % compared to the scenario with the main value of the map. A percental variation of the soil storage shows a doubling of the flood discharges, if the storage size is halved and a reduction up to 20% using a doubled one. Finally, a Monte Carlo Simulation is performed using the statistical data of the soil map combined with a normal distribution, whereby the

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  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. Resolving hydrologic water balances through a novel error analysis approach, with application to the Tahoe basin

    NASA Astrophysics Data System (ADS)

    Trask, James C.; Fogg, Graham E.; Puente, Carlos E.

    2017-03-01

    We introduce a new approach for improving estimates of water balance components, applicable to a multi-period water balance series for a lake, watershed, or other area of any size. It consists of making use of statistical relationships between a component series estimate and the residual errors of the water mass balance series. Through this approach, two novel specific techniques are developed. The first, 'precipitation-decorrelation', entails implementing a criterion of decorrelation of residual errors from precipitation estimates. The second, 'residual-redistribution', consists of redistributing each residual error over initial water balance component estimates, in accord with an error minimization criterion for each component series. Efficacy is tested using series of annual water balances for the Tahoe Basin. Upon implementation of precipitation-decorrelation, a tightly bounded statistical estimate of mean annual Lake Tahoe evaporation is obtained, which closely matches independent measurement-based estimates. Residual-redistribution yields revised estimates of annual series of Tahoe areal precipitation and watershed runoff, which are each shown to have substantially reduced random error variance. Highly precise revised estimates of inter-annual variations in Tahoe precipitation have enabled resolution of the watershed multi-year 'memory' of precipitation, and more reliable separation of inter-annual changes in watershed storage from inter-annual variations in atmospheric loss.

  6. 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.

  7. Effects of Dynamic Forcing on Hillslope Water Balance Models

    DTIC Science & Technology

    2004-01-01

    processes on variability of monthly river discharge. Water Resources Research, 38(11):Art. No. 1235, November 2002. [27] J. Molenat and C. Gascuel-Odoux...Pielke Sr., C. Taylor, C. Tague , C. J. Tremback, and P. L. Vidale. Coupled atmosphere-biophysics-hydrology models for environmental modeling. Journal

  8. 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.

  9. 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

  10. 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.

  11. Shodagor Family Strategies : Balancing Work and Family on the Water.

    PubMed

    Starkweather, Kathrine E

    2017-03-11

    The Shodagor of Matlab, Bangladesh, are a seminomadic community of people who live and work on small wooden boats, within the extensive system of rivers and canals that traverse the country. This unique ecology places particular constraints on family and economic life and leads to Shodagor parents employing one of four distinct strategies to balance childcare and provisioning needs. The purpose of this paper is to understand the conditions that lead a family to choose one strategy over another by testing predictions about socioecological factors that impact the sexual division of labor, including a family's stage in the domestic cycle, aspects of the local ecology, and the availability of alloparents. Results show that although each factor has an impact on the division of labor individually, a confluence of these factors best explains within-group, between-family differences in how mothers and fathers divide subsistence and childcare labor. These factors also interact in particular ways for Shodagor families, and it appears that families choose their economic strategies based on the constellation of constraints that they face. The results of these analyses have implications for theory regarding the sexual division of labor across cultures and inform how Shodagor family economic and parenting strategies should be contextualized in future studies.

  12. Water balance of global aquifers revealed by groundwater footprint.

    PubMed

    Gleeson, Tom; Wada, Yoshihide; Bierkens, Marc F P; van Beek, Ludovicus P H

    2012-08-09

    Groundwater is a life-sustaining resource that supplies water to billions of people, plays a central part in irrigated agriculture and influences the health of many ecosystems. Most assessments of global water resources have focused on surface water, but unsustainable depletion of groundwater has recently been documented on both regional and global scales. It remains unclear how the rate of global groundwater depletion compares to the rate of natural renewal and the supply needed to support ecosystems. Here we define the groundwater footprint (the area required to sustain groundwater use and groundwater-dependent ecosystem services) and show that humans are overexploiting groundwater in many large aquifers that are critical to agriculture, especially in Asia and North America. We estimate that the size of the global groundwater footprint is currently about 3.5 times the actual area of aquifers and that about 1.7 billion people live in areas where groundwater resources and/or groundwater-dependent ecosystems are under threat. That said, 80 per cent of aquifers have a groundwater footprint that is less than their area, meaning that the net global value is driven by a few heavily overexploited aquifers. The groundwater footprint is the first tool suitable for consistently evaluating the use, renewal and ecosystem requirements of groundwater at an aquifer scale. It can be combined with the water footprint and virtual water calculations, and be used to assess the potential for increasing agricultural yields with renewable groundwaterref. The method could be modified to evaluate other resources with renewal rates that are slow and spatially heterogeneous, such as fisheries, forestry or soil.

  13. Electrofreezing of water droplets under electrowetting fields.

    PubMed

    Carpenter, Katherine; Bahadur, Vaibhav

    2015-02-24

    Electrofreezing is the electrically induced nucleation of ice from supercooled water. This work studies ice nucleation in electrowetted water droplets, wherein there is no electric field inside the droplet resting on a dielectric layer. Instead, there is an interfacial electric field and charge buildup at the solid-liquid interface. This situation is in contrast to most previous electrofreezing studies, which have used bare electrodes, involve current flow, and have a volumetric electric field inside the liquid. Infrared and high-speed visualizations of static water droplets are used to analyze surface electrofreezing. Ultrahigh electric fields of up to 80 V/μm are applied, which is one order of magnitude higher than in previous studies. The results facilitate an in-depth understanding of various mechanisms underlying electrofreezing. First, it is seen that interfacial electric fields alone can significantly elevate freezing temperatures by more than 15 °C, in the absence of current flow. Second, the magnitude of electrofreezing induced temperature elevation saturates at high electric field strengths. Third, the polarity of the interfacial charge does not significantly influence electrofreezing. Overall, it is seen that electrofreezing nucleation kinetics is primarily influenced by the three-phase boundary and not the solid-liquid interface. Through careful electrofreezing measurements on dielectric layers with pinholes to allow current flow, the individual role of electric fields and electric currents on electrofreezing is isolated. It is seen that both the electric field and the electric current influence electrofreezing; however, the physical mechanisms are very different.

  14. 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

  15. 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...

  16. 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

  17. 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.

  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. 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

  20. 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.

  1. Modeling water balance distribution in a natural semiarid region of central Mexico using a SVAT model

    NASA Astrophysics Data System (ADS)

    Mastachi-Loza, C. A.; Braud, I.; Gonzalez-Sosa, E.; Centro de Investigaciones Del Agua de Querétaro

    2010-12-01

    Around the world water is becoming insufficient, 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 study was carried out from October 2005 to October 2008 in two semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Cadereyta in Queretaro State. The work aim was to provide a better understanding of the hydrological processes that occur in semiarid ecosystems, quantifying and modeling 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 Atmosphere Transfer) model was used based on a parameterization of the soil, plants and atmosphere components. It was 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.

  2. Water balance at a low-level radioactive-waste disposal site

    USGS Publications Warehouse

    Healy, R.W.; Gray, J.R.; De Vries, G. M.; Mills, P.C.

    1989-01-01

    The water balance at a low-level radioactive-waste disposal site in northwestern Illinois was studied from July 1982 through June 1984. Continuous data collection allowed estimates to be made for each component of the water-balance equation independent of other components. The average annual precipitation was 948 millimeters. Average annual evapotranspiration was estimated at 637 millimeters, runoff was 160 millimeters, change in water storage in a waste-trench cover was 24 millimeters, and deep percolation was 208 millimeters. The magnitude of the difference between precipitation and all other components (81 millimeters per year) indicates that, in a similar environment, the water-budget method would be useful in estimating evapotranspiration, but questionable for estimation of other components. Precipitation depth and temporal distribution had a very strong effect on all other components of the water-balance equation. Due to the variability of precipitation from year to year, it appears that two years of data are inadequate for characterization of the long-term average water balance at the site.

  3. Energy requirements for a swimming pool through a water-atmosphere energy balance

    SciTech Connect

    Almanza, F.; Lara, J. )

    1994-07-01

    The methodology displayed here is to calculate the energy requirements for heating a swimming pool to a desired temperature. This methodology consists of an energy balance between water-atmosphere as is used in the temperature evaluation of cooling ponds in power plants. Different mathematical expressions are given to calculate such a balance. It is necessary to know the month of the year, the ambient temperature, relative humidity, wind velocity, and solar radiation. With these parameters it is possible to know the natural temperature of the water, natural evaporation, energy needed to reach a determined swimming pool temperature and the evaporation of the heated pool.

  4. Adjusting soil water balance calculations for light rainfall, dew, and fog.

    NASA Astrophysics Data System (ADS)

    Snyder, R. L.; Spano, D.; Moratiel, R.

    2012-04-01

    The main sources of water for an irrigated crop include irrigation applications, precipitation, water tables, fog interception, and dew formation. For a well-drained soil in a climate where there are a few events of fog, dew, or light rainfall, computing a water balance is relatively easy, but it is complicated in regions characterized by considerable events of fog, dew and light rainfall. In these regions, growers are hesitant to use ET-Based scheduling because the cumulative crop evapotranspiration is often considerably higher than the soil water depletion. We will present a simple and practical procedure to estimate the contribution of fog interception, dew, and light rainfall to daily crop evapotranspiration in California and to show how to use the information to improve water balance calculations for efficient water use in irrigation. It is assumed that the relationship between normalized hourly ETo and time of the day is similar to the relationship between normalized hourly ETc and time of the day. We can describe the change in soil water depletion (ΔDSW) on that day as: ΔDsw =ETc x F where F is the fraction of ETc coming from the soil, and F is determined using the expression: F = --1--- 1+ e(t-11.265.5) Where t is the approximate local standard time in hours when the crop dries. This simple method improves water balance scheduling and the adoption of the ET-based scheduling method in microclimates where fog, dew, and light rainfall are common.

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  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. 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. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, balance year 2002

    USGS Publications Warehouse

    Bidlake, William R.; Josberger, Edward G.; Savoca, Mark E.

    2004-01-01

    Winter snow accumulation and summer snow and ice ablation were measured at South Cascade Glacier, Washington, to estimate glacier mass balance quantities for balance year 2002. The 2002 glacier-average maximum winter snow balance was 4.02 meters, the second largest since 1959. The 2002 glacier summer, net, and annual (water year) balances were -3.47, 0.55, and 0.54 meters, respectively. The area of the glacier near the end of the balance year was 1.92 square kilometers, and the equilibrium-line altitude and the accumulation area ratio were 1,820 meters and 0.84, respectively. During September 20, 2001 to September 13, 2002, the terminus retreated 4 meters, and computed average ice speeds in the ablation area ranged from 7.8 to 20.7 meters per year. Runoff from the subbasin containing the glacier and from an adjacent non-glacierized basin were measured during part of the 2002 water year. Air temperature, precipitation, atmospheric water-vapor pressure, wind speed and incoming solar radiation were measured at selected locations near the glacier.

  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. Occurrence and simulation of trihalomethanes in swimming pool water: A simple prediction method based on DOC and mass balance.

    PubMed

    Peng, Di; Saravia, Florencia; Abbt-Braun, Gudrun; Horn, Harald

    2016-01-01

    Trihalomethanes (THM) are the most typical disinfection by-products (DBPs) found in public swimming pool water. DBPs are produced when organic and inorganic matter in water reacts with chemical disinfectants. The irregular contribution of substances from pool visitors and long contact time with disinfectant make the forecast of THM in pool water a challenge. In this work occurrence of THM in a public indoor swimming pool was investigated and correlated with the dissolved organic carbon (DOC). Daily sampling of pool water for 26 days showed a positive correlation between DOC and THM with a time delay of about two days, while THM and DOC didn't directly correlate with the number of visitors. Based on the results and mass-balance in the pool water, a simple simulation model for estimating THM concentration in indoor swimming pool water was proposed. Formation of THM from DOC, volatilization into air and elimination by pool water treatment were included in the simulation. Formation ratio of THM gained from laboratory analysis using native pool water and information from field study in an indoor swimming pool reduced the uncertainty of the simulation. The simulation was validated by measurements in the swimming pool for 50 days. The simulated results were in good compliance with measured results. This work provides a useful and simple method for predicting THM concentration and its accumulation trend for long term in indoor swimming pool water.

  15. 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

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

    PubMed

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

    2012-03-01

    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 (D(a)) 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 D(a). Phloem flows were required for growth, with gradual recovery after a step increase in D(a). Xylem flows alone were unable to support growth, but did supply transpiration and were responsive to D(a)-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.

  17. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 1986-1991 balance years

    USGS Publications Warehouse

    Krimmel, Robert M.

    2000-01-01

    Mass balance and climate variables are reported for South Cascade Glacier, Washington, for the years 1986-91. These variables include air temperature, precipitation, water runoff, snow accumulation, snow and ice melt terminus position, surface level, and ice speed. Data are reduced to daily and monthly values where appropriate. The glacier-averaged values of spring snow accumulation and fall net balance given in this report differ from previous results because amore complete analysis is made. Snow accumulation values for the1986-91 period ranged from 3.54 (water equivalent) meters in 1991 to2.04 meters in 1987. Net balance values ranged from 0.07 meters in1991 to -2.06 meters in 1987. The glacier became much smaller during the 1986-91 period and retreated a cumulative 50 meters.

  18. 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

  19. Detailed balance condition and ultraviolet stability of scalar field in Horava-Lifshitz gravity

    NASA Astrophysics Data System (ADS)

    Borzou, Ahmad; Lin, Kai; Wang, Anzhong

    2011-05-01

    Detailed balance and projectability conditions are two main assumptions when Horava recently formulated his theory of quantum gravity - the Horava-Lifshitz (HL) theory. While the latter represents an important ingredient, the former often believed needs to be abandoned, in order to obtain an ultraviolet stable scalar field, among other things. In this paper, because of several attractive features of this condition, we revisit it, and show that the scalar field can be stabilized, if the detailed balance condition is allowed to be softly broken. Although this is done explicitly in the non-relativistic general covariant setup of Horava-Melby-Thompson with an arbitrary coupling constant λ, generalized lately by da Silva, it is also true in other versions of the HL theory. With the detailed balance condition softly breaking, the number of independent coupling constants can be still significantly reduced. It is remarkable to note that, unlike other setups, in this da Silva generalization, there exists a master equation for the linear perturbations of the scalar field in the flat Friedmann-Robertson-Walker background.

  20. 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.

  1. 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.

  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. 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...

  4. 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...

  5. 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

  6. In-vehicle CO ingression: validation through field measurements and mass balance simulations.

    PubMed

    Esber, Layale Abi; El-Fadel, Mutasem

    2008-05-01

    In this study a mass balance modeling approach with measured out-vehicle carbon monoxide (CO) levels and trip-specific movement record as boundary conditions were used to simulate in-vehicle CO concentration profiles. The simulation results were coupled with field measurements to demonstrate the occurrence of CO ingression into the vehicle compartment from the engine combustion and/or exhaust return of the test vehicle. Agreement between field and simulation results was obtained for variable amounts of infiltrated CO equivalent to an in-vehicle emission rate of 250 to 1250 mg/h of CO depending on the vehicle ventilation settings.

  7. Simultaneity of water demand from hydrants of distribution networks and operational irrigation-water balance

    NASA Astrophysics Data System (ADS)

    Sánchez, Raúl; Rodriguez-Sinobas, Leonor; Juana, Luis; Laguna, Francisco V.

    2013-04-01

    In pressure irrigation-water 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. In this work the influence of the performance on the control of the applied volume during the whole irrigation events in an irrigation campaign has been assessed. Theoretical flow rates values have been introduced into a validated in laboratory PRV performance model coupled with a water distribution network. 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 network.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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%.

  13. The Role of Vegetation Dynamics on the Soil Water Balance in Water-Limited Ecosystems

    NASA Astrophysics Data System (ADS)

    Montaldo, N.; Rondena, R.; Albertson, J. D.; Mancini, M.

    2003-12-01

    The structure and function of the vegetation regulates the exchange of mass, energy and momentum across the biosphere-atmosphere interface. Vegetation dynamics are usually neglected, other than seasonal phenology, in land surface models (LSMs). However, changes in vegetation densities, influencing the partitioning of incoming solar energy into sensible and latent heat fluxes, can result in long-term changes in both local and global climates (e.g., precipitation and temperature), which in turn will feedback to affect the vegetation growth. In semi-arid regions, this may result in persistent drought and desertification, with substantial impacts on the human populations of these regions through reduction in agricultural productivity and reduction in quantity and quality of water supply. With an objective of finding a simple vegetation model able to accurately simulate the leaf area index (LAI) dynamics, vegetation models of different level of complexity (e.g., including or not the modeling of the root biomass or the modeling of the dead biomass) are developed and compared. The vegetation dynamics models are coupled to a LSM, with the vegetation models providing the green biomass and the LAI evolution through time, and the LSM using this information in the computation of the land surface fluxes and updating the soil water content in the root-zone. We explore the models on a case study of a water limited grass field in California. Results show that a simple vegetation model that simulates the living aboveground green biomass (i.e., with low parameterization and computational efforts) is able to accurately simulate the LAI. Results also highlight the importance of including the plant growth model in the LSM when studying the climate-soil-vegetation interactions and the impact of watershed management practices on the scarce water resources over moderate to long time scales. The inclusion of the vegetation model in the LSM is demonstrated to be essential for assessing the

  14. 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

  15. 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.

  16. Monitoring the water balance of Lake Victoria, East Africa, from space

    NASA Astrophysics Data System (ADS)

    Swenson, Sean; Wahr, John

    2009-05-01

    SummaryUsing satellite gravimetric and altimetric data, we examine trends in water storage and lake levels of multiple lakes in the Great Rift Valley region of East Africa for the years 2003-2008. GRACE total water storage estimates reveal that water storage declined in much of East Africa, by as much as 60 {mm}/{year}, while altimetric data show that lake levels in some large lakes dropped by as much as 1-2 m. The largest declines occurred in Lake Victoria, the Earth's second largest freshwater body. Because the discharge from the outlet of Lake Victoria is used to generate hydroelectric power, the role of human management in the lake's decline has been questioned. By comparing catchment water storage trends to lake level trends, we confirm that climatic forcing explains only about 50decline. This analysis provides an independent means of assessing the relative impacts of climate and human management on the water balance of Lake Victoria that does not depend on observations of dam discharge, which may not be publically available. In the second part of the study, the individual components of the lake water balance are estimated. Satellite estimates of changes in lake level, precipitation, and evaporation are used with observed lake discharge to develop a parameterization for estimating subsurface inflows due to changes in groundwater storage estimated from satellite gravimetry. At seasonal timescales, this approach provides closure to Lake Victoria's water balance to within 17 {mm}/{month}. The third part of this study uses the water balance of a downstream water body, Lake Kyoga, to estimate the outflow from Lake Victoria remotely. Because Lake Kyoga is roughly 20 times smaller in area than Lake Victoria, its water balance is strongly influenced by inflow from Lake Victoria. Lake Kyoga has been shown to act as a linear reservoir, where its outflow is proportional to the height of the lake. This model can be used with satellite altimetric lake levels to estimate a

  17. QSPR modeling of octanol/water partition coefficient of antineoplastic agents by balance of correlations.

    PubMed

    Toropov, Andrey A; Toropova, Alla P; Raska, Ivan; Benfenati, Emilio

    2010-04-01

    Three different splits into the subtraining set (n = 22), the set of calibration (n = 21), and the test set (n = 12) of 55 antineoplastic agents have been examined. By the correlation balance of SMILES-based optimal descriptors quite satisfactory models for the octanol/water partition coefficient have been obtained on all three splits. The correlation balance is the optimization of a one-variable model with a target function that provides both the maximal values of the correlation coefficient for the subtraining and calibration set and the minimum of the difference between the above-mentioned correlation coefficients. Thus, the calibration set is a preliminary test set.

  18. 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.

  19. 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.

  20. 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.

  1. An attempt to perform water balance in a Brazilian municipal solid waste landfill.

    PubMed

    São Mateus, Maria do Socorro Costa; Machado, Sandro Lemos; Barbosa, Maria Cláudia

    2012-03-01

    This paper presents an attempt to model the water balance in the metropolitan center landfill (MCL) in Salvador, Brazil. Aspects such as the municipal solid waste (MSW) initial water content, mass loss due to decomposition, MSW liquid expelling due to compression and those related to weather conditions, such as the amount of rainfall and evaporation are considered. Superficial flow and infiltration were modeled considering the waste and the hydraulic characteristics (permeability and soil-water retention curves) of the cover layer and simplified uni-dimensional empirical models. In order to validate the modeling procedure, data from one cell at the landfill were used. Monthly waste entry, volume of collected leachate and leachate level inside the cell were monitored. Water balance equations and the compressibility of the MSW were used to calculate the amount of leachate stored in the cell and the corresponding leachate level. Measured and calculated values of the leachate level inside the cell were similar and the model was able to capture the main trends of the water balance behavior during the cell operational period.

  2. 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.

  3. Distinct Soil Microbial Communities in habitats of differing soil water balance on the Tibetan Plateau.

    PubMed

    Li, Yuntao; Adams, Jonathan; Shi, Yu; Wang, Hao; He, Jin-Sheng; Chu, Haiyan

    2017-04-12

    Global change may be a severe threat to natural and agricultural systems, partly through its effects in altering soil biota and processes, due to changes in water balance. We studied the potential influence of changing soil water balance on soil biota by comparing existing sites along a natural water balance gradient in the Qinghai-Tibetan Plateau. In this study, the community structure of bacteria, archaea and eukaryotes differed between the different soil water conditions. Soil moisture was the strongest predictor of bacterial and eukaryotic community structure, whereas C/N ratio was the key factor predicting variation in the archaeal community. Bacterial and eukaryotic diversity was quite stable among different soil water availability, but archaeal diversity was dramatically different between the habitats. The auxotype of methanogens also varied significantly among different habitats. The co-varying soil properties among habitats shaped the community structure of soil microbes, with archaea being particularly sensitive in terms of community composition, diversity and functional groups. Bacterial and archaeal phylogenetic community turnover was mainly driven by deterministic processes while stochastic processes had stronger effects on eukaryotic phylogenetic community turnover. Our work provides insight into microbial community, functional group and phylogenetic turnover under different soil conditions in low-latitude alpine ecosystem.

  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. Tonicity balance, and not electrolyte-free water calculations, more accurately guides therapy for acute changes in natremia.

    PubMed

    Carlotti, A P; Bohn, D; Mallie, J P; Halperin, M L

    2001-05-01

    The usual way to decide why hyponatremia or hypernatremia has developed and to plan goals for its therapy is to analyze events in electrolyte-free water (EFW) terms. We shall demonstrate that an EFW balance does not supply this information. Rather, one must calculate mass balances for water and sodium plus potassium separately (a tonicity balance) to understand the basis for the change in natremia and the proper goals for its therapy. These points are illustrated with a clinical example.

  6. 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

  7. Water balance along a chain of tundra lakes: A 20-year isotopic perspective

    NASA Astrophysics Data System (ADS)

    Gibson, J. J.; Reid, R.

    2014-11-01

    Stable isotope measurements and isotope mass balance (IMB) calculations are presented in support of an unprecedented 20-year water balance assessment for a tailings pond and a chain of downstream lakes at the Salmita-Tundra mine site, situated near Courageous Lake, Northwest Territories, Canada (65°03‧N; 111°11‧W). The method is shown to provide a comprehensive annual and interannual perspective of water balance fluxes along a chain of lakes during the period 1991-2010, without the need for continuous streamflow gauging, and reveals important lake-order-dependent patterns of land-surface runoff, discharge accumulation, and several key diagnostic ratios, i.e., evaporation/inflow, evaporation/evapotranspiration, land-surface-runoff/precipitation and discharge/ precipitation. Lake evaporation is found to be a significant component of the water balance, accounting for between 26% and 32% of inflow to natural lakes and between 72% and 100% of inflow to mine-tailings ponds. Evaporation/evapotranspiration averages between 7% and 22% and is found to be higher in low-precipitation years, and in watersheds with a higher proportion of lakes. Runoff ratios for land-surface drainages and runoff ratios for watersheds (including lakes) ranged between 14-47% and 20-47%, respectively, and were higher in low precipitation years, in watersheds with a higher proportion of lakes, and in watersheds less affected by mining development. We propose that in general these two runoff ratios will likely converge as lake order increases and as land cover conditions become regionally representative. Notably, the study demonstrates application of IMB, validated with streamflow measurements, to constrain local water balance in a remote low-arctic region. For IMB chain-of-lakes applications, it underlines the importance of accounting for evaporatively-enriched upstream sources to avoid overestimation of evaporation losses.

  8. Water Balance Study on a Semiarid Regional Landscape in South Texas: Effects of Anthropogenic Land Disturbance

    NASA Astrophysics Data System (ADS)

    Camarena, C.; Ren, J.; Jones, K.

    2004-12-01

    While extensive vegetation manipulation has been encouraged by many administrators and extension groups, its effect on the water balance is complex and the hypothesis that removal of woody plants consistently reduces evapotranspiration, increases soil water content, and water yield remains unproven. This project focuses on examination of the effects of various land management practices on the overall water balance for semiarid regional landscapes. The project location is at the Wellhausen Ranch Research Station located near Laredo, TX, consisting of 5,280 acres of shrub landscape dominated by honey mesquite shrub species. This ranch has undergone various land disturbances such as root plowing and cattle overgrazing that have caused damage to the vegetation and natural communities. Five research sites were chosen within the ranch including a control site, a gravel dominated site, a root plowed site, an undisturbed site, and a second research site with different vegetative cover to represent different land use environments. Parameters that are being measured for the water balance study include precipitation, soil moisture, surface runoff, evaporation, and evapotranspiration. Preliminary results show that for the period of January to September of 2004, temperatures in the Wellhausen Ranch range from 29.1 ºF to 106.9 ºF, indicating hot summers and mild winters. 68 rainfall events have occurred, which resulted in 16.24 inches of total precipitation. Patterns were detected in soil moisture profiles reflecting the differences of soil moisture at different depths in the soil. Analysis of variance (ANOVA) indicates significant differences in the soil moisture in the five research sites. In addition, micro-lysimeter results show higher evaporation rates in the gravel dominated and the second research sites. These preliminary results indicate a potentially significant influence of anthropogenic land disturbance on a landscape water balance in the semiarid Nueces River basin.

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

    NASA Astrophysics Data System (ADS)

    Wang, Xu-Sheng; Zhou, Yangxiao

    2016-09-01

    The Budyko framework represents the general relationship between the evapotranspiration ratio (F) and the aridity index (φ) for the mean annual steady-state water balance at the catchment scale. It is interesting to investigate whether this standard F - φ space can also be applied to capture the shift of annual water balance in catchments with varying dryness. Previous studies have made significant progress in incorporating the storage effect into the Budyko framework for the non-steady conditions, whereas the role of groundwater-dependent evapotranspiration was not investigated. This study investigates how groundwater-dependent evapotranspiration causes the shift of the annual water balance in the standard Budyko space. A widely used monthly hydrological model, the ABCD model, is modified to incorporate groundwater-dependent evapotranspiration into the zone with a shallow water table and delayed groundwater recharge into the zone with a deep water table. This model is applied in six catchments in the Erdos Plateau, China, to estimate the actual annual evapotranspiration. Results show that the variations in the annual F value with the aridity index do not satisfy the standard Budyko formulas. The shift of the annual water balance in the standard Budyko space is a combination of the Budyko-type response in the deep groundwater zone and the quasi-energy limited condition in the shallow groundwater zone. Excess evapotranspiration (F > 1) could occur in dry years, which is contributed by the significant supply of groundwater for evapotranspiration. Use of groundwater for irrigation can increase the frequency of the F > 1 cases.

  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. 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.

  12. 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.

  13. EXPERIMENTAL STUDY ON WATER BALANCE IN A NEGATIVE PRESSURE DIFFERENCE IRRIGATION SYSTEM

    NASA Astrophysics Data System (ADS)

    Moniruzzaman, S. M.; Fukuhara, Teruyuki; Terasaki, Hiroaki

    Negative pressure difference irrigation (NPDI) is considered to be an attractive mode of irrigation because water use efficiency in this case is higher than that in conventional irrigation methods such as basin irrigation, furrow irrigation and sprinkler irrigation. In order to investigate the water balance in a NPDI system, experiments involving the use of a soil column, porous pipe and water reservoir were carried out in a temperature and humidity controlled room. The evaporation (Meva), supplied water (Msup), soil water storage (Msoil), wetted soil surface area and configuration of the wetted soil around the porous pipe were determined for three different negative pressures. Empirical equations were proposed for the calculation of Meva and Msoil. The proposed simple model could well reproduce the temporal variations in Meva and Msoil. With a decrease in the negative pressure, the water use efficiency increased and was in the range of 0.92 to 0.97.

  14. 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

  15. Water temperature, voluntary drinking and fluid balance in dehydrated taekwondo athletes.

    PubMed

    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 pointsFor 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.

  16. Evapotranspiration dynamics in a boreal peatland and its impact on the water and energy balance

    NASA Astrophysics Data System (ADS)

    Wu, Jiabing; Kutzbach, Lars; Jager, Daniel; Wille, Christian; Wilmking, Martin

    2010-12-01

    Hydrological conditions play a key role in the carbon cycle of northern peatlands. This study examines the evapotranspiration (ET) dynamics and its impact on the water and energy balance in response to differing meteorological conditions during the exceptionally dry year 2006 and the normal wet year 2007 at a boreal peatland in Finland. Energy and water vapor fluxes were determined continuously using the eddy covariance approach. Daily ET rates varied considerably during the growing season and averaged 2.23 ± 0.15 mm d-1 and 1.59 ± 0.07 mm d-1 in the dry and wet year, respectively. Synoptic weather conditions as reflected by incoming radiation and water vapor pressure deficit (VPD) were the key factors controlling ET. Differences in the precipitation patterns and summer temperature also accounted for some of the observed differences in ET between the 2 years. No evidence was found for a relationship between ET rates and water table level, probably due to the relatively high water table level even in the dry year. Latent heat flux dominated the energy balance, particularly in the dry year 2006 with 60% of cumulative precipitation returned to the atmosphere through ET. In the wet year 2007, runoff dominated the water loss, and only 36% of the cumulative precipitation was returned to the atmosphere through ET. While the annual water balance regime of the peatland was mainly regulated by the precipitation pattern, daily measured ET was closely related to potential evaporation, and latent heat flux could be well modeled by the Penman-Monteith approach, suggesting two feasible schemes for ET prediction in peatlands under well watered conditions.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Proposed water balance equation for municipal solid waste landfills in Jordan.

    PubMed

    Aljaradin, Mohammad; Persson, Kenneth M

    2013-10-01

    This article presents a water balance equation for predicting leachate generation in municipal solid waste (MSW) landfills located in semi-arid areas, using the Akaider landfill in Jordan as an example. HYDRUS-2D/3D software was used to model the effect of co-disposal of wastewater into the landfill on the leachate production rates and for comparison with the results of the simulation of the proposed water balance equation parameters. A series of simulations was carried out for a 30-year period. The suggested water balance equation predicted that leachate will percolate to a depth of 50 m in the simulated period. The result indicates that the co-disposed wastewater plays a major role in controlling the rate and magnitude of the contaminants that percolate from the MSW leachate. As the initial water content of the waste increases, there is greater mobilisation of salts. The concentration of chloride at a given location increased and the time required for the chloride to reach this location decreased as a consequence. However, eliminating the co-disposed wastewater will significantly minimise leachate generation and decrease possible groundwater contamination. This equation is applicable to areas that have geological and hydrological properties similar to Jordan.

  2. Bose-Einstein condensates with balanced gain and loss beyond mean-field theory

    NASA Astrophysics Data System (ADS)

    Dast, Dennis; Haag, Daniel; Cartarius, Holger; Main, Jörg; Wunner, Günter

    2016-11-01

    Most of the work done in the field of Bose-Einstein condensates with balanced gain and loss has been performed in the mean-field approximation using the P T -symmetric Gross-Pitaevskii equation. In this work we study the many-particle dynamics of a two-mode condensate with balanced gain and loss described by a master equation in Lindblad form whose purity periodically drops to small values but then is nearly completely restored. This effect cannot be covered by the mean-field approximation, in which a completely pure condensate is assumed. We present analytic solutions for the dynamics in the noninteracting limit and use the Bogoliubov backreaction method to discuss the influence of the on-site interaction. Our main result is that the strength of the purity revivals is almost exclusively determined by the strength of the gain and loss and is independent of the amount of particles in the system and the interaction strength. For larger particle numbers, however, strong revivals are shifted towards longer times, but by increasing the interaction strength these strong revivals again occur earlier.

  3. A well-balanced numerical scheme for shallow water simulation on adaptive grids

    NASA Astrophysics Data System (ADS)

    Zhang, H. J.; Zhou, J. Z.; Bi, S.; Li, Q. Q.; Fan, Y.

    2014-04-01

    The efficiency of solving two-dimensional shallow-water equations (SWEs) is vital for simulation of large-scale flood inundation. For flood flows over real topography, local high-resolution method, which uses adaptable grids, is required in order to prevent the loss of accuracy of the flow pattern while saving computational cost. This paper introduces an adaptive grid model, which uses an adaptive criterion calculated on the basis of the water lever. The grid adaption is performed by manipulating subdivision levels of the computation grids. As the flow feature varies during the shallow wave propagation, the local grid density changes adaptively and the stored information of neighbor relationship updates correspondingly, achieving a balance between the model accuracy and running efficiency. In this work, a well-balanced (WB) scheme for solving SWEs is introduced. In reconstructions of Riemann state, the definition of the unique bottom elevation on grid interfaces is modified, and the numerical scheme is pre-balanced automatically. By the validation against two idealist test cases, the proposed model is applied to simulate flood inundation due to a dam-break of Zhanghe Reservoir, Hubei province, China. The results show that the presented model is robust and well-balanced, has nice computational efficiency and numerical stability, and thus has bright application prospects.

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

    PubMed

    Chan, Karen; Eikerling, Michael

    2014-02-07

    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.

  5. 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)

  6. 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.

  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. 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.

  9. Fresh water balance of the Gulf Stream system in a regional model study

    NASA Astrophysics Data System (ADS)

    Gerdes, R.; Biastoch, A.; Redler, R.

    We investigate the dependence of surface fresh water fluxes in the Gulf Stream and North Atlantic Current (NAC) area on the position of the stream axis which is not well represented in most ocean models. To correct this shortcoming, strong unrealistic surface fresh water fluxes have to be applied that lead to an incorrect salt balance of the current system. The unrealistic surface fluxes required by the oceanic component may force flux adjustments and may cause fictitious long-term variability in coupled climate models. To identify the important points in the correct representation of the salt balance of the Gulf Stream a regional model of the northwestern part of the subtropical gyre has been set up. Sensitivity studies are made where the westward flow north of the Gulf Stream and its properties are varied. Increasing westward volume transport leads to a southward migration of the Gulf Stream separation point along the American coast. The salinity of the inflow is essential for realistic surface fresh water fluxes and the water mass distribution. The subpolar-subtropical connection is important in two ways: The deep dense flow from the deep water mass formation areas sets up the cyclonic circulation cell north of the Gulf Stream. The surface and mid depth flow of fresh water collected at high northern latitudes is mixed into the Gulf Stream and compensates for the net evaporation at the surface.

  10. [Water balance of different density artificial Caragana microphylla shrubs in Horqin sand land].

    PubMed

    Lamusa, A; Longjun, C I; Yang, Xiaohui; Jiang, Deming

    2006-01-01

    Employing water balance equation, this paper estimated the evapotranspiration of different density Caragana microphylla shrubs during their growing season. The results showed that during this season, the soil water content under artificial C. microphylla shrubs decreased with their increasing planting density. The average soil water content of 0.5 m x 1 m and 1 m x 2 m density artificial C. microphylla shrubs was below wilting humidity (1.55%), while that of 2 m x 2 m density and natural shrubs was kept above 1.60% which could meet the demand of shrubs growth. The evapotranspiration increased with increasing planting densities, being the highest (297.81 mm) in 0.5 m x 1 m density artificial C. microphylla shrubs, which accounted for 97.90% of the total rainfall during growing season, and the lowest (279.71 mm) in 2 m x 2 m density shrubs. By the end of growth phase, soil water content had a surplus of 24.49 mm. According to the soil water status and water balance theory, the appropriate planting density of C. microphylla shrubs in Horqin sand land should be 2 m x 2 m.

  11. A water balance model for Saxonian catchments - present state and projections up to 2100

    NASA Astrophysics Data System (ADS)

    Winkler, Peter; Hauffe, Corina; Baldy, Agnes; Schwarze, Robert

    2014-05-01

    The impact of climate change on the regional water balance regime may have severe consequences for agriculture, forestry and water resources management. In this respect the following questions arise: Will extensive irrigation be necessary on Saxonian crop land in future? Which are the necessary adaptions in water resources management? Are new agricultural and forestry concepts necessary? Therefore, the project KliWES aims at modelling the present water balance regime for whole Saxonia (with the exception of the mining regions and the Elbe-corridor which is largely governed by flood events). Moreover, the effects of climate projections from the WetReg model (CEC) on the water balance regime have been investigated. The calibration strategy relies on splitting up the measured discharges into the major water balance components (evaporation, surface flow, subsurface flow and percolation) by a geometrical analysis of the hydrograph (DIFGA, Schwarze et al.). Thereafter, the water balance software ArcEGMO (Pfützner et al.) has been calibrated on these water balance components. Calibration parameters include correction factors for soil macroporosity, evapo-transpiration and the distribution factor between fast and slow groundwater components. Geological and Soil data have been drawn from official databases (LfULG). Subareas where no continuous gauge data are available have been parametrised by a regionalisation procedure relying on correlations between parameters and physical properties of the subareas considered. Possibilities and limitations of such a regionalisation procedure have been pointed out. Focal point of the present study is an investigation of water balance components in different spatial and temporal resolutions. The Results of the model for the climate projections show drastic increase of evaporation and decrease of groundwater recharge especially in the north-eastern parts of Saxonia (Lausitz). Here, this problem is worsened by the predominantly sandy soils

  12. 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

  13. 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.

  14. 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)

  15. 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

  16. A well-balanced scheme for the shallow-water equations with topography or Manning friction

    NASA Astrophysics Data System (ADS)

    Michel-Dansac, Victor; Berthon, Christophe; Clain, Stéphane; Foucher, Françoise

    2017-04-01

    We consider the shallow-water equations with Manning friction or topography, as well as a combination of both these source terms. The main purpose of this work concerns the derivation of a non-negativity preserving and well-balanced scheme that approximates solutions of the system and preserves the associated steady states, including the moving ones. In addition, the scheme has to deal with vanishing water heights and transitions between wet and dry areas. To address such issues, a particular attention is paid to the study of the steady states related to the friction source term. Then, a Godunov-type scheme is obtained by using a relevant average of the source terms in order to enforce the required well-balance property. An implicit treatment of both topography and friction source terms is also exhibited to improve the scheme while dealing with vanishing water heights. A second-order well-balanced MUSCL extension is designed, as well as an extension for the two-dimensional case. Numerical experiments are performed in order to highlight the properties of the scheme.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

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

    NASA Astrophysics Data System (ADS)

    Flerchinger, G. N.; Marks, D.; Reba, M. L.; Yu, Q.; Seyfried, M. S.

    2010-06-01

    Precipitation variability and complex topography often create a mosaic of vegetation communities in mountainous headwater catchments, creating a challenge for measuring and interpreting energy and mass fluxes. Understanding the role of these communities in modulating energy, water and carbon fluxes is critical to quantifying the variability in energy, carbon, and water balances across landscapes. The focus of this paper was: (1) to demonstrate the utility of eddy covariance (EC) systems in estimating the evapotranspiration component of the water balance of complex headwater mountain catchments; and (2) to compare and contrast the seasonal surface energy and carbon fluxes across a headwater catchment characterized by large variability in precipitation and vegetation cover. Eddy covariance systems were used to measure surface fluxes over sagebrush (Artemesia arbuscula and Artemesia tridentada vaseyana), aspen (Populus tremuloides) and the understory of grasses and forbs beneath the aspen canopy. Peak leaf area index of the sagebrush, aspen, and aspen understory was 0.77, 1.35, and 1.20, respectively. The sagebrush and aspen canopies were subject to similar meteorological forces, while the understory of the aspen was sheltered from the wind. Missing periods of measured data were common and made it necessary to extrapolate measured fluxes to the missing periods using a combination of measured and simulated data. Estimated cumulative evapotranspiratation from the sagebrush, aspen trees, and aspen understory were 384 mm, 314 mm and 185 mm. A water balance of the catchment indicated that of the 699 mm of areal average precipitation, 421 mm was lost to evapotranspiration, and 254 mm of streamflow was measured from the catchment; water balance closure for the catchment was within 22 mm. Fluxes of latent heat and carbon for all sites were minimal through the winter. Growing season fluxes of latent heat and carbon were consistently higher above the aspen canopy than from the

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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.

  7. Balancing Public Trust Resources of Mono Lake and Los Angeles' Water Right: An Economic Approach

    NASA Astrophysics Data System (ADS)

    Loomis, John B.

    1987-08-01

    The contingent valuation method (CVM) is used to quantify the Public Trust values of Mono Lake at alternative lake levels. The dichotomous choice approach to contingent valuation is employed using a logit model. The economic benefit to California residents of preserving Mono Lake is estimated to be 1.5 billion. Purchase of replacement water and power would cost 26.2 million annually. On efficiency grounds, reallocation of water for maintenance of Public Trust values at Mono Lake is warranted. The CVM appears to be a useful methodology to evaluate the balancing and feasibility tests of the expanded Public Trust doctrine suggested by the California Supreme Court.

  8. The water balance equations in saline playa lakes: comparison between experimental and recent data from Quero Playa Lake (central Spain)

    NASA Astrophysics Data System (ADS)

    Sánchez-Moral, S.; Ordóñez, S.; Benavente, D.; García del Cura, M. A.

    2002-04-01

    The Quero Playa Lake is an ephemeral saline playa lake located in the La Mancha region of central Spain. In this study, a daily monitoring of the brine physical properties, water activity, brine depth and main climatic parameters was simultaneously carried out together with determining the precipitation sequence of minerals. Field data were compared with the results of simulating the water evaporation in an environmental chamber. In this simulation, a similar hydrochemical composition for the saline lake was used, and the main climatic parameters, temperature and humidity, were controlled. The water balance equation for saline lakes has usually been described using the Wood and Sanford equation [Econ. Geol., 85(1990) 1226-1235]. Our experimental results required us to revise the water balance equation for the brine depth variations (d h/d t), that may be expressed as follows: {dh }/{dt }=p 1+k {A B}/{A L}+S I-S O-ξ-H+D, where p (mm) is the precipitation; k is the drainage coefficient of the lake; AL is the lake surface; AB is the drainage basin surface; SI and SO are the contribution of influent and effluent seepage to the depth of brine in the lake. The term ξ is the evaporation/condensation, defined as ξ= kpW( aW-RH), where k is the mass transfer coefficient (Dalton's equation); pW is the water pressure in equilibrium with the air; aW is the water activity of the brine; RH is the relative humidity. The other terms: H and D, correct the brine depth loss or/and gain a consequence of hydrated saline mineral precipitation and early diagenetic hydration/dehydration reactions. As a consequence of the above, we suggest that the water balance equation for saline lakes can be an important consideration in the interpretation of their evolution. The precipitation of hydrated saline minerals and the early diagenetic dehydration/hydration reactions imply changes in the d h/d t curves. As a result, the interpretation of the sequence of primary saline minerals in older

  9. 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

  10. Positivity-preserving high order well-balanced discontinuous Galerkin methods for the shallow water equations

    SciTech Connect

    Xing, Yulong; Zhang, Xiangxiong; Shu, Chi-wang

    2010-01-01

    Shallow water equations with a non-flat bottom topography have been widely used to model flows in rivers and coastal areas. An important difficulty arising in these simulations is the appearance of dry areas where no water is present, as standard numerical methods may fail in the presence of these areas. These equations also have still water steady state solutions in which the flux gradients are nonzero but exactly balanced by the source term. In this paper we propose a high order discontinuous Galerkin method which can maintain the still water steady state exactly, and at the same time can preserve the non-negativity of the water height without loss of mass conservation. A simple positivity-preserving limiter, valid under suitable CFL condition, will be introduced in one dimension and then extended to two dimensions with rectangular meshes. Numerical tests are performed to verify the positivity-preserving property, well-balanced property, high order accuracy, and good resolution for smooth and discontinuous solutions.

  11. Portrayal of fuzzy recharge areas for water balance modelling - a case study in northern Oman

    NASA Astrophysics Data System (ADS)

    Gerner, A.; Schütze, N.; Schmitz, G. H.

    2012-06-01

    The research project IWAS Oman aims at implementing integrated water resources management (IWRM) to a pilot area in Al Batinah, Oman. This requires - amongst others - a realistic assessment of groundwater recharge to the alluvial aquifer which obviously has to be based upon the extension of recharge areas. In this context, the subsequent investigation focuses on the role of vagueness as regards the portrayal of the areas that provide water for particular aquifers. For that purpose, concepts of fuzziness in spatial analysis are applied to describe possible extents of recharge areas. In general, any water assessment is based on clearly delineated boundaries. However, in many cases, aquifer recharge areas are not clearly defined due to the nature of the study area. Hence, surfaces indicating a gradual membership to the recharge area of a particular aquifer are used in this investigation. These surfaces, which are based on available qualitative information, visualise a potential range of spatial extension. With regard to water balance calculations, functional relationships in tabular form are derived as well. Based on a regionalisation approach providing spatially distributed recharge rates, the corresponding recharge volume is calculated. Hence, this methodology provides fuzzy input data for water balance calculations. Beyond the portrayal of one singular aquifer recharge area, this approach also supports the complementary consideration of adjacent areas.

  12. Variations in water balance and recharge potential at three western desert sites

    USGS Publications Warehouse

    Gee, G.W.; Wierenga, P.J.; Andraski, B.J.; Young, M.H.; Fayer, M.J.; Rockhold, M.L.

    1994-01-01

    Radioactive and hazardous waste landfills exist at numerous desert locations in the USA. At these locations, annual precipitation is low and soils are generally dry, yet little is known about recharge of water and transport of contaminants to the water table. Recent water balance measurements made at three desert locations, Las Cruces, NM, Beatty, NV, and the U.S. Department of Energy's Hanford Site in the state of Washington, provide information on recharge potential under three distinctly different climate and soil conditions. All three sites show water storage increases with time when soils are coarse textured and plants are removed from the surface, the rate of increase being influenced by climatic variables such as precipitation, radiation, temperature, and wind. Lysimeter data from Hanford and Las Cruces indicate that deep drainage (recharge) from bare, sandy soils can range from 10 to >50% of the annual precipitation. At Hanford, when desert plants are present on sandy or gravelly surface soils, deep drainage is reduced but not eliminated. When surface soils are silt loams, deep drainage is eliminated whether plants are present or not. At Las Cruces and Beatty, the presence of plants eliminated deep drainage at the measurement sites. Differences in water balance between sites are attributed to precipitation quantity and distribution and to soil and vegetation types. The implication for waste management at desert locations is that surface soil properties and plant characteristics must be considered in waste site design in order to minimize recharge potential.

  13. Carbon and water balance of European croplands throughout the 20th century

    NASA Astrophysics Data System (ADS)

    Gervois, SéBastien; Ciais, Philippe; de Noblet-Ducoudré, Nathalie; Brisson, Nadine; Vuichard, Nicolas; Viovy, Nicolas

    2008-06-01

    We assessed the effects of rising atmospheric CO2, changing climate, and farmers' practice on the carbon and water balance of European croplands during the past century (1901-2000). The coupled vegetation-crop model ORCHIDEE-STICS is applied over western Europe for C3 crops (winter wheat) and for maize, with prescribed historical agricultural practice changes. Not surprisingly, the enormous crop yield increase observed in all European regions, 300-400% between 1950 and 2000, is found to be dominantly explained by improved practice and varieties selection, rather than by rising CO2 (explaining a ˜11% uniform increase in yield) and changing climate (no further change in yield on average, but causing a decrease of ˜19% in the southern Iberian Peninsula). Agricultural soil carbon stocks in Europe are modeled to have decreased between 1950 and 1970, and since then to have increased again. Thus, the current stocks only differ by 1 ± 6 tC ha-1 from their 1900 value. Compensating effects of increasing yields on the one hand (increasing stocks) and of higher harvest index values and ploughing on the other hand (decreasing stocks) occur. Each of these processes taken individually has the potential to strongly alter the croplands soil carbon balance in the model. Consequently, large uncertainties are associated to the estimated change in carbon stocks between 1901 and 2001, roughly ±6 tC ha-1 a-1. In our most realistic simulation, the current cropland carbon balance is a net sink of 0.16 ± 0.15 tC ha-1 a-1. The annual water balance of cropland soils is influenced by increasing crop water use efficiency, one third of which is caused by rising CO2. However, increasing water use efficiency occurred mainly in spring and winter, when water is not limiting for plant growth, whereas no strong savings of soil water are achieved in summer through elevated CO2. Overall, trends in cultivation practices have caused a 3 times larger increase of water use efficiency than rising CO2.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. A well-balanced unified gas-kinetic scheme for multiscale flow transport under gravitational field

    NASA Astrophysics Data System (ADS)

    Xiao, Tianbai; Cai, Qingdong; Xu, Kun

    2017-03-01

    The gas dynamics under gravitational field is usually associated with multiple scale nature due to large density variation and a wide variation of local Knudsen number. It is challenging to construct a reliable numerical algorithm to accurately capture the non-equilibrium physical effect in different regimes. In this paper, a well-balanced unified gas-kinetic scheme (UGKS) for all flow regimes under gravitational field will be developed, which can be used for the study of non-equilibrium gravitational gas system. The well-balanced scheme here is defined as a method to evolve an isolated gravitational system under any initial condition to a hydrostatic equilibrium state and to keep such a solution. To preserve such a property is important for a numerical scheme, which can be used for the study of slowly evolving gravitational system, such as the formation of star and galaxy. Based on the Boltzmann model with external forcing term, the UGKS uses an analytic time-dependent (or scale-dependent) solution in the construction of the discretized fluid dynamic equations in the cell size and time step scales, i.e., the so-called direct modeling method. As a result, with the variation of the ratio between the numerical time step and local particle collision time, the UGKS is able to recover flow physics in different regimes and provides a continuous spectrum of gas dynamics. For the first time, the flow physics of a gravitational system in the transition regime can be studied using the UGKS, and the non-equilibrium phenomena in such a gravitational system can be clearly identified. Many numerical examples will be used to validate the scheme. New physical observation, such as the correlation between the gravitational field and the heat flux in the transition regime, will be presented. The current method provides an indispensable tool for the study of non-equilibrium gravitational system.

  19. 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

  20. Wnt signaling balances specification of the cardiac and pharyngeal muscle fields.

    PubMed

    Mandal, Amrita; Holowiecki, Andrew; Song, Yuntao Charlie; Waxman, Joshua S

    2017-02-01

    Canonical Wnt/β-catenin (Wnt) signaling plays multiple conserved roles during fate specification of cardiac progenitors in developing vertebrate embryos. Although lineage analysis in ascidians and mice has indicated there is a close relationship between the cardiac second heart field (SHF) and pharyngeal muscle (PM) progenitors, the signals underlying directional fate decisions of the cells within the cardio-pharyngeal muscle field in vertebrates are not yet understood. Here, we examined the temporal requirements of Wnt signaling in cardiac and PM development. In contrast to a previous report in chicken embryos that suggested Wnt inhibits PM development during somitogenesis, we find that in zebrafish embryos Wnt signaling is sufficient to repress PM development during anterior-posterior patterning. Importantly, the temporal sensitivity of dorso-anterior PMs to increased Wnt signaling largely overlaps with when Wnt signaling promotes specification of the adjacent cardiac progenitors. Furthermore, we find that excess early Wnt signaling can cell autonomously promote expansion of the first heart field (FHF) progenitors at the expense of PM and SHF within the anterior lateral plate mesoderm (ALPM). Our study provides insight into an antagonistic developmental mechanism that balances the sizes of the adjacent cardiac and PM progenitor fields in early vertebrate embryos.

  1. Phloem transport in Ricinus: Its dependence on the water balance of the tissues.

    PubMed

    Hall, S M; Milburn, J A

    1973-03-01

    Phloem exudation from Ricinus has been examined in plants subjected to changes in water balance induced by a number of means. The results have provided a clear demonstration that the phloem system can operate osmotically. When the availability of water in the xylem is reduced by withholding water, the rate of exudation decreases sharply and this is accompanied by a rise in the sap concentration. On removing the water stress, the rate increases rapidly with a corresponding fall in sap concentration.Small variations in water availability do not give significant results and may be buffered by responses from the plant itself. This could also explain the insignificant changes in sap composition during exudation previously reported, where exudation rate, which should bear some relation to sieve tube turgor pressure, seems independent of sap concentration. Fluctuations in exudation rate are large in comparison with the changes in sap concentration when severe water stresses are applied. This result, coupled with the observation that exudation will occur from plants under considerable water stress suggests the operation of a "sugar pump" capable of maintaining a high turgor pressure at the source against a considerable water potential gradient. The main "pump" is probably located in the leaves.Thus interpreted, the results seem to accord with the Münch pressure flow hypothesis in all significant aspects.

  2. Spatio-temporal Variability of Controls on Water Balance Components in a Western Mountainous Headwater Basin

    NASA Astrophysics Data System (ADS)

    Kelleher, C.; Wagener, T.; McGlynn, B. L.; Marshall, L. A.; Jencso, K. G.

    2011-12-01

    Headwater basins represent a large portion of the stream network in the United States and provide crucial but largely unquantified ecosystem services, including export of water and nutrients to downstream sources and habitat for sensitive aquatic species. Investigating controls on hydrologic fluxes within these headwaters is important for understanding how these basins might respond to change in climate or land use. Our work focuses on characterizing controls on water balance components within the Tenderfoot Creek Experimental Forest (TCEF) via experimental data-modeling synthesis. Extensive monitoring within the basin offers the opportunity to compare model behavior against multiple water balance components and hydrologic fluxes, including snowmelt, snow water equivalent, evapotranspiration, catchment storage, and streamflow. We model the basin using the Distributed Hydrology Vegetation Soil Model (DHSVM) and apply variance-based global sensitivity analysis to quantify the spatio-temporal variability of controls on different hydrologic fluxes across the study domain. The results provide a unique opportunity for testing the consistency between DHSVM and our perception of the watershed processes in the TCEF.

  3. 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).

  4. Electropumping of water with rotating electric fields.

    PubMed

    De Luca, Sergio; Todd, B D; Hansen, J S; Daivis, Peter J

    2013-04-21

    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.

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. Balancing local order and long-ranged interactions in the molecular theory of liquid water.

    PubMed

    Shah, J K; Asthagiri, D; Pratt, L R; Paulaitis, M E

    2007-10-14

    A molecular theory of liquid water is identified and studied on the basis of computer simulation of the TIP3P model of liquid water. This theory would be exact for models of liquid water in which the intermolecular interactions vanish outside a finite spatial range, and therefore provides a precise analysis tool for investigating the effects of longer-ranged intermolecular interactions. We show how local order can be introduced through quasichemical theory. Long-ranged interactions are characterized generally by a conditional distribution of binding energies, and this formulation is interpreted as a regularization of the primitive statistical thermodynamic problem. These binding-energy distributions for liquid water are observed to be unimodal. The Gaussian approximation proposed is remarkably successful in predicting the Gibbs free energy and the molar entropy of liquid water, as judged by comparison with numerically exact results. The remaining discrepancies are subtle quantitative problems that do have significant consequences for the thermodynamic properties that distinguish water from many other liquids. The basic subtlety of liquid water is found then in the competition of several effects which must be quantitatively balanced for realistic results.

  17. Comparison of the Effects on Dynamic Balance Ability of Warming up in Water Versus on the Ground.

    PubMed

    Lim, Kyoung Il; Hwnagbo, Gak; Nam, Hyung Chun; Cho, Yong Ho

    2014-04-01

    [Purpose] This research was designed to find out how the so-called "dynamic balance" is affected by doing different types of warm up exercises. In particular, the research is focused on the difference in the effect on dynamic Balance of warming up in water versus on the ground. [Subjects and Methods] Twenty healthy adults were the subjects of this study, with 10 people assigned each to two groups, one warming up in water and another warming up on the ground. The dynamic balance was measured for all subjects before the warming up. The group warming up on the ground conducted active stretching on the ground, and the group warming up in water conducted stretching in water by using water as resistance. [Results] The results indicate that warming up in water has a more powerful effect on a subject's dynamic balance than warming up on the ground. [Conclusion] The group warming up in water, who made use of the viscosity and flow of the water, showed better balance than the group warming up on the ground. Warming up in water, which entails an element of resistance, should be implemented in warm-up routines in the future.

  18. 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

  19. 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

  20. 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.

  1. Determining water balance components at a lysimeter site in north-eastern Austria

    NASA Astrophysics Data System (ADS)

    Nolz, Reinhard; Kammerer, Gerhard; Cepuder, Peter

    2014-05-01

    The water balance of a certain soil profile in a certain time interval is subjected to changes of soil water content within the respective profile, and fluxes at its upper and lower boundary such as evapotranspiration and percolation, respectively. Weighing lysimeters are valuable instruments for water balance studies. Typically, mass changes - thus, changes of soil profile water content - are detected by a weighing system, while percolating water is measured by a tipping bucket or a weighed storage tank, and precipitation is measured by a rain gauge. Consequently, evapotranspiration can be determined by solving a simple water balance equation. However, a typical problem is that using separately measured precipitation data may cause implausible (negative) evapotranspiration. As a solution, the quantities can be determined directly from lysimeter mass changes, which are assumed to be positive due to precipitation and negative due to evapotranspiration. This method requires short measuring intervals and precise data. In this regard, data management of primarily older lysimeter facilities may be improved to fulfil these criteria. At an experimental site in north-eastern Austria hourly water balance components were determined using a reference lysimeter that was installed 1983 and equipped with lever-arm-counterbalance weighing system. A disadvantage of such systems is their sensitivity to external disturbances, mainly forces exerted by wind, which can significantly decrease measuring accuracy. Hence, we firstly studied the mechanical performance of the system regarding wind effects and oscillation behavior, and tested averaging procedures on noisy raw data to enhance measurement accuracy. The measurement accuracy for a wind velocity <5 m/s (measured in 10 m height) was ±0.4 kg (equivalent to ±0.14 mm); at a larger wind velocity the accuracy was three times lower, but there was no linear relationship. Modifying the averaging procedure would improve accuracy to ±0

  2. Climate change impacts on the water balance of coastal and montane rainforests in northern Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Wallace, Jim; McJannet, Dave

    2012-12-01

    SummaryHow the water balance of coastal and montane rainforests in northern Queensland could change in response to climate change was examined using physically based models of interception and transpiration along with long term weather records. Future rainfall and temperature changes were based on the most recent climate modelling for the region and were assumed to fall within the range ±20% for rainfall with a temperature increase of 1-3 K. Climate change will affect the water balance of Australian rainforests primarily via rainfall changes rather than temperature. Any given change in rainfall produces a greater change in downstream runoff, the amplification ranging from 1.1 to 1.5 in the wet season to a factor of 12 in the dry season. Changes in wet season rainfall (80% of the annual total) dominate the total annual amount of water released for downstream flow, but dry season rainfall (20% of the annual total) changes are also very important as they affect onset and the duration of the period when there is no runoff. This period is currently ˜110 days and this would change by ±30 days under the above climate scenarios. There are also potential in situ impacts of climate change that affect how long the rainforest canopy is wet, which may have important implications for the epiphytes and mosses that depend on these wet canopy conditions. Similarly there may be significant impacts on downstream freshwater species whose life cycles are adapted to the current dry season flow regime.

  3. Comparison of Characteristic of Water Balance between Evergreen Coniferous and Deciduous Broad-leaved Forests

    NASA Astrophysics Data System (ADS)

    Hisada, Shigeta; Senge, Masateru; Ito, Kengo; Maruyama, Toshisuke

    Hydrological observation was carried out at two basins occupied mainly by evergreen coniferous forest of Chamaecyparis obtusa and deciduous broad-leaved forest of Quercus crispula in order to clarify the influences of different forest type on water balance. The analysis of short-time period water-budget method showed that the evapotranspiration of coniferous forest was more than broad-leaved one. By calculating transpiration from Priestley-Taylor equation, intercepted evaporation was separated from evapotranspiration. The result of comparison of intercepted evaporation between two basin was that intercepted evaporation of coniferous basin was more than that of broad-leaved basin. From separating total runoff into direct and base flow components; it was shown that there was no difference in direct runoff of two basins, so the differences of total runoff of two basins were caused due to the difference of base flow. From the above analysis of water balance components, it is clarified that the different forest type influences the amount of intercepted evaporation and base flow.

  4. Maternal brooding in the children's python (Antaresia childreni) promotes egg water balance.

    PubMed

    Lourdais, Olivier; Hoffman, Ty C M; Denardo, Dale F

    2007-07-01

    Parental care provides considerable benefits to offspring and is widespread among animals, yet it is relatively uncommon among squamate reptiles (e.g., lizards and snakes). However, all pythonine snakes show extended maternal egg brooding with some species being facultatively endothermic. While facultative endothermy provides thermal benefits, the presence of brooding in non-endothermic species suggests other potential benefits of brooding. In this study we experimentally tested the functional significance of maternal brooding relative to water balance in the children's python, Antaresia childreni, a small species that does not exhibit facultative endothermy. Clutch evaporative water loss (EWL) was positively correlated with clutch mass and was much lower than expected values based on individual eggs. The conglomerate clutch behaved as a single unit with a decreasing surface area to volume ratio as clutch size increased. Maternal brooding had a dramatic impact on evaporation from eggs, reducing and possibly eliminating clutch EWL. In a separate experiment, we found that viability of unattended eggs is highly affected by humidity level, even in the narrow range from 75 to 100% relative humidity at 30.5 degrees C (20-33 mg m(-3 )absolute humidity). However, the presence of the brooding female ameliorated this sensitivity, as viability of brooded clutches at 75% relative humidity was higher than that of non-brooded eggs at either the same absolute humidity or at near-saturated conditions. Overall, these results demonstrate that brooding behavior strongly promotes egg water balance (and thus egg viability) in children's pythons.

  5. Comparison of root water uptake modules using either the surface energy balance or potential transpiration

    NASA Astrophysics Data System (ADS)

    Braud, Isabelle; Varado, Noémie; Olioso, Albert

    2005-01-01

    Numerical models simulating changes in soil water content with time rely on accurate estimation of root water uptake. This paper considers two root water uptake modules that have a compensation mechanism allowing for increased root uptake under conditions of water stress. These modules, proposed by Lai and Katul and Li et al. [Adv. Water Resour. 23 (2000) 427 and J. Hydrol. 252 (2001) 189] use potential transpiration weighted, for each soil layer, by a water stress and a compensation function in order to estimate actual transpiration. The first objective of the paper was to assess the accuracy of the proposed root extraction modules against two existing data sets, acquired under dry conditions for a winter wheat and a soybean crop. In order to perform a fair comparison, both modules were included as possible root water extraction modules within the Simple Soil Plant Atmosphere Transfer (SiSPAT) model. In this first set of simulations, actual transpiration was calculated using the solution of the surface energy budget as implemented in the SiSPAT model. Under such conditions, both root extraction modules were able to reproduce accurately the time evolution of soil moisture at various depths, soil water storage and daily evaporation. Results were generally improved when we activated the compensation mechanisms. However, we showed that Lai and Katul [Adv. Water Resour. 23 (2000) 427] module was sensitive to soil hydraulic properties through its water stress function, whereas the Li et al. [J. Hydrol. 252 (2001) 189] module was not very sensitive to the specification of its parameter. The latter module is therefore recommended for inclusion into a larger scale hydrological model, due to its robustness. When water balance models are run at larger scales or on areas with scarce data, actual transpiration is often calculated using models based on potential transpiration without solving the surface energy balance. The second objective of the paper was to assess the loss of

  6. 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

  7. 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.

  8. 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

  9. The role of insect water balance in pollination ecology: Xylocopa and Calotropis.

    PubMed

    Willmer, P G

    1988-08-01

    Two carpenter bees (Xylocopa spp.) in southern Israel both use the asclepiad Calotropis procera as a primary nectar source. This plant genus is coevolved with carpenter bees, and aspects of the insect-flower interaction in Israel suggest that the smaller bee, X. sulcatipes, is the natural co-adapted pollinator, a view borne out by the geographical distributions of the species concerned. There are significant mismatches between the plant and the larger X. pubescens, involving physical fit and behaviour. These mismatches are particularly evident when the physiologies of the bees and the plant are considered. The different sizes and colours of the two bees lead to different daily activity patterns, only X. sulcatipes being thermally suited to, and thus abundant at, times of maximum nectar production by Calotropis. Similarly the water requirements of X. sulcatipes are finely balanced with the water production in the floral nectar; this bee gains just enough water when foraging to restore its blood concentration and production in the floral nectar; for deposition in the nest. X. pubescens does not incur net water loss in flight and gains too much water from Calotropis flowers, necessitating copious urination and 'tonguelashing'. Hence physiological information can be of use in deciphering insect-plant coevolutionary patterns, and the water component of nectar is confirmed as a potentially major determinant of foraging activities. The circumstances where this will be particularly true, and cases where it may not apply, are discussed.

  10. 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.

  11. 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.

  12. 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

  13. Canopy Water Balance of an Elfin Cloud Forest at Alakahi, Hawaii

    NASA Astrophysics Data System (ADS)

    Delay, J. K.; Giambelluca, T. W.; Juvik, J. O.

    2006-12-01

    The contribution of cloudwater or fog, to the water balance of tropical mountain forests has been the subject of increasing attention in recent decades. This study estimates the water falling to the forest floor as a result of cloud water interception (CWI) by the canopy in a short stature tropical montane cloud forest (TMCF) with abundant epiphytic vegetation. The study site, located in the Alakahi region of Kohala on the island of Hawai'i, receives abundant orographic rainfall and is frequently immersed in clouds. Cloudwater interception was estimated from meteorological data using the Gash interception model to calculate canopy water balance at the event scale for precipitation events with, and without fog precipitation recorded by a mechanical collector in the forest canopy. Cloudwater interception was derived as a residual by comparison of measured and predicted throughfall during events with fog precipitation. Storage capacity of the major canopy bryophytes and ferns, as well as that of the mossy mat carpeting the forest floor, was also estimated from observed distribution and storage capacity. The calculated contribution of CWI was equivalent to 11% of the total throughfall. The annualized 219 mm is substantially lower than for CWI previously estimated at a nearby exposed, forest-edge location where estimated CWI and throughfall exceeded rainfall. Canopy epiphyte water storage capacity accounted for 3.53 mm and the mossy mat on the forest floor was estimated to store up to 22 mm. The epiphyte storage during precipitation events was far less than the estimated storage capacity; however, epiphytes represented a significant potential moisture source for interception loss between precipitation events.

  14. Off-line simulation of the Amazon water balance: a sensitivity study with implications for GSWP

    NASA Astrophysics Data System (ADS)

    Chapelon, N.; Douville, H.; Kosuth, P.; Oki, T.

    2002-03-01

    As a first step of the international Global Soil Wetness Project (GSWP), several state-of-the-art land surface models were recently forced by 1° × 1° atmospheric analyses and observations to obtain global soil moisture climatologies over the 1987-1988 period. Besides the 6-hourly atmospheric forcing, the models also used common boundary conditions (soil and vegetation parameters), also drawn from the ISLSCP Initiative I dataset. While very few in situ observations are available to validate the soil moisture fields, the simulated runoff can be compared with river discharge measurements. This strategy is employed here to assess the quality of GSWP simulations based on the ISBA land surface model. The ISBA runoff is transformed into 1° × 1° gridded stream flows by using the TRIP river routing model. The focus is on the Amazon basin where all models participating in GSWP showed a strong underestimation in the annual runoff and a significant lag in the annual cycle of the runoff. A sample of 31 gauging stations is selected to validate the gridded runoff simulated by ISBA. Sensitivity tests have been performed, that suggest that deficiencies in both the precipitation forcing and the boundary conditions provided by ISLSCP contribute to the poor simulation of the Amazon water balance. The use of alternative precipitation, soil and vegetation datasets allows ISBA to produce a more realistic annual runoff, although the amplitude of the annual cycle remains exaggerated at the downstream gauging station of Obidos. Among these experiments, the simulation leading to the best annual runoff has been used as a reference to test simple modifications in the TRIP river routing model. Tuning the parameters of TRIP or increasing the resolution of the river channel network is not sufficient to improve the annual cycle of the simulated discharge. New developments are necessary to deal more explicitly with the floodplain inundation that occurs during the rainy season over the Amazon

  15. Regional estimation of base recharge to ground water using water balance and a base-flow index.

    PubMed

    Szilagyi, Jozsef; Harvey, F Edwin; Ayers, Jerry F

    2003-01-01

    Naturally occurring long-term mean annual base recharge to ground water in Nebraska was estimated with the help of a water-balance approach and an objective automated technique for base-flow separation involving minimal parameter-optimization requirements. Base recharge is equal to total recharge minus the amount of evapotranspiration coming directly from ground water. The estimation of evapotranspiration in the water-balance equation avoids the need to specify a contributing drainage area for ground water, which in certain cases may be considerably different from the drainage area for surface runoff. Evapotranspiration was calculated by the WREVAP model at the Solar and Meteorological Surface Observation Network (SAMSON) sites. Long-term mean annual base recharge was derived by determining the product of estimated long-term mean annual runoff (the difference between precipitation and evapotranspiration) and the base-flow index (BFI). The BFI was calculated from discharge data obtained from the U.S. Geological Survey's gauging stations in Nebraska. Mapping was achieved by using geographic information systems (GIS) and geostatistics. This approach is best suited for regional-scale applications. It does not require complex hydrogeologic modeling nor detailed knowledge of soil characteristics, vegetation cover, or land-use practices. Long-term mean annual base recharge rates in excess of 110 mm/year resulted in the extreme eastern part of Nebraska. The western portion of the state expressed rates of only 15 to 20 mm annually, while the Sandhills region of north-central Nebraska was estimated to receive twice as much base recharge (40 to 50 mm/year) as areas south of it.

  16. 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,…

  17. 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.

  18. 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.; Ramírez-Hernández, 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

  19. A comparison of two models for simulating the water balance of soil covers under semi-arid conditions

    SciTech Connect

    Chammas, G.A.; Geddis, M.; McCaulou, D.R.

    1999-07-01

    Numerical water-balance modeling of store-and-release soil covers for hypothetical mine tailings was conducted using the Hydrologic Evaluation of Landfill Performance (HELP) and SoilCover models. The objective of the modeling was to compare the utility of both models in a semi-arid environment. Although values for input parameters were chosen to make simulations as identical as possible between models, differences in model solution methods and discretization led to different water-balance predictions. Specifically, SoilCover predicted less percolation than HELP, because HELP uses simplified water-routing algorithms which may over predict infiltration and under predict subsequent evapotranspiration. Since SoilCover explicitly solves physically based governing equations for heat and water flow, its predictions more accurately represent the water balance in semi-arid regions where evapotranspiration dominates, HELP can only conservatively predict percolation in dry environments.

  20. Water Balance Modelling - Does The Required Model Complexity Change With Scale?

    NASA Astrophysics Data System (ADS)

    Blöschl, G.; Merz, R.

    An important issue in modelling the water balance of catchments is what is the suitable model complexity. Anecdotal evidence suggests that the model complexity required to model the water balance accurately decreases with catchment scale but so far very few studies have quantified these possible effects. In this paper we examine the model per- formance as a function of catchment scale for a given model complexity which allows us to infer, whether the required model complexity changes with scale. We also exam- ine whether the calibrated parameter values change with scale or are scale invariant. In a case study we analysed 700 catchments in Austria with catchment sizes ranging from 10 to 100 000 km2. 30 years of daily data (runoff, precipitation, air temperature, air humidity) were analysed. A spatially lumped, conceptual, HBV style soil mois- ture accounting scheme was used which involved fifteen model parameters including snow processes. Five parameters were preset and ten parameters were calibrated on observed daily streamflow. The calibration period was about 10 years and the verifi- cation period was about 20 years. Model performance (in terms of Nash-Sutcliffe effi- ciency) was examined both for the calibration and the verification periods. The mean efficiency over all catchments only decreased slightly when moving from the calibra- tion to the verification (from R2 = 0.65 to 0.60). The results suggest that the model efficiencies (both for the calibration and the verification) do not change which catch- ment scale for scales smaller than 10 000 km2 but beyond this scale there is a slight decrease in model performance. This means that for these very large scales, a spatial subdivision of the lumped model is needed to allow for spatial differences in rainfall. The results also suggest that the model parameters are not scale dependent. We con- clude that the complexity required for water balance models of catchments does not change with scale for catchment sizes

  1. 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

  2. A model for predicting continental-scale vegetation distribution and water balance

    SciTech Connect

    Neilson, R.P.

    1995-05-01

    A Mapped atmosphere-Plant-Soil System (MAPSS) has been constructed for simulating the potential biosphere impacts and biosphere-atmosphere feedbacks from climatic change. The system calculates the potential vegetation type and leaf area that could be supported at a site, within the constraints of the abiotic climate. Both woody vegetation and grass are supported and compete for light and water. The woody vegetation can be either trees or shrubs, evergreen or deciduous, and needleleaved or broadleaved. A complete site water balance is calculated and integrates the vegetation leaf area and stomatal conductance in canopy transpiration and soil hydrology. The MAPSS model accurately simulates the distributions of forests, grasslands, and deserts and reproduces observed monthly runoff. The model can be used for predictions of new vegetation distribution patterns, soil moisture, and runoff patterns in alternative climates. 112 refs., 11 figs., 4 tabs.

  3. 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.

  4. 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.

  5. Signal to noise ratio in water balance maps with different resolution

    NASA Astrophysics Data System (ADS)

    Yan, Ziqi; Gottschalk, Lars; Wang, Jianhua

    2016-12-01

    What is the best resolution of annual water balance maps for a correct balance between the basic spatial signal in the observations of precipitation, actual evapotranspiration and runoff across a larger drainage basin and the error in estimates for grid cells in the map to avoid giving a false impression of accuracy? To answer this question an approach based a signal to noise ratio is proposed, which allows finding the optimal resolution maximizing the signal in the map. The approach is demonstrated on gauge data in the Huai River Basin, China. Stochastic interpolation methods were applied to create grid maps of long-term mean values, as well as for estimating variances of the three water balance components in a range of scales from 5 × 5 km to 200 × 200 km2 grid cells. Interpolation algorithms using covariances of long-term means of data with different spatial support were developed. The identified optimal resolutions by the signal to noise ratio appeared to be very different - 10 × 10, 50 × 50, and 30 × 30 km2 for precipitation, actual evapotranspiration, and runoff, respectively. These values are directly linked to the observation network densities. The magnitude of the signal to noise ratio shows similar strong differences with values 34, 3.7, and 5.4, respectively. It gives a direct indication of the reliability of the map, which can be considered as satisfactory only for precipitation for the data available for the present study. The critical factors for this magnitude are parameters characterising the spatial covariance in data and the network density.

  6. 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

  7. Impact of climate change on water balance, and nutrient leaching of (pre-) alpine grassland soils

    NASA Astrophysics Data System (ADS)

    Fu, Jin; Lu, Haiyan; Butterbach-bahl, Klaus; Kiese, Ralf

    2013-04-01

    On a global perspective terrestrial biosphere hosts significant pools of carbon and nitrogen. Due to cool and moist climatic conditions alpine grassland soils of moderate elevation (app. 1000m) in particular, are rich in soil organic carbon and associated nitrogen. In the framework of an in-situ climate change experiment we test the hypothesis that soil organic carbon and nitrogen are either volatilized (GHG emissions) or leached with seepage water due to increase in air temperature as induced by climate change. The infrastructure of the in-situ climate change experiment was funded by Helmholtz society and BMBF and allowed IMK-IFU to install a lysimeter network with undisturbed intact grassland soil cores (diameter approx. 1 m, depth 1.4 m, 2-3 t of soil) at three sites (Graswang 860m, Rottenbuch 750m, Fendt 600m) differing in altitude and climate. The lysimeter network consisting of a total of 36 lysimeters is operated since September 2011 and is run for climate change research with a long term perspective (>10years). Lysimeters were partly moved along the altitudinal gradient, with some soil cores still staying at sites as controls and some others translocated from higher elevation to sites at lower elevation with higher temperatures and slightly lower mean annual rainfall. The different components of the water balance i.e. precipitation, evapotranspiration and groundwater recharge of each lysimeter are measured by precision weighing of the lysimeters and a separate container for collection of seepage water at the lower boundary condition (1.4m). In addition, soil moisture (volumetric water content as well as water tension) and temperature are measured with sensors installed in 10, 30, 50, 140cm soil depth. Soil water in 10, 30, 50 and 140cm soil depth is drawn into glass bottles by under-pressurized suction cups. Water samples are collected regularly any 2 weeks and more often (e.g. 3 times a week) during fertilization events, and analyzed for nutrient

  8. Human impacts on land cover and water balances in a coastal Mediterranean county.

    PubMed

    Bellot, Juan; Bonet, Andreu; Peña, Juan; Sánchez, Juan Rafael

    2007-03-01

    We analyzed the effects of changes in land cover on the water balance in Spain's Marina Baixa County, on the Mediterranean coast. To reveal how different land management strategies have affected the area's environment, four municipalities within the same catchment were studied: Benidorm, Callosa d'en Sarrià, Beniardà, and Guadalest. In the municipalities of Callosa and Benidorm, the proportion of the area covered by woodland declined by 4.2% and 30.2%, respectively, and woodland was replaced by agriculture and urban development. The abandonment of farmland produced a 17% increase in the proportion of the area covered by vegetation in Guadalest and Beniardá, where frequent forest fires have exacerbated a decrease in the area of pine woodland. Tourism development in Benidorm has been accompanied by an increase in the transportation infrastructure and by an expansion of areas with an impermeable surface, with the lowest level of infiltration into the aquifer system. These changes have generated a net water deficit in Callosa and Benidorm of more than 6 Mm(3)/year, creating a high demand for water imported from other municipalities (Guadalest and Beniardá) or from outside of the county to maintain the sustainability of the current water management strategies. The Marina Baixa case study is representative of many of the world's coastal areas that are undergoing rapid urban development based on an inappropriate understanding of human progress based mainly on economic development and thus provides insights into water management in other areas.

  9. 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.

  10. Water balance creates a threshold in soil pH at the global scale.

    PubMed

    Slessarev, E W; Lin, Y; Bingham, N L; Johnson, J E; Dai, Y; Schimel, J P; Chadwick, O A

    2016-11-21

    Soil pH regulates the capacity of soils to store and supply nutrients, and thus contributes substantially to controlling productivity in terrestrial ecosystems. However, soil pH is not an independent regulator of soil fertility-rather, it is ultimately controlled by environmental forcing. In particular, small changes in water balance cause a steep transition from alkaline to acid soils across natural climate gradients. Although the processes governing this threshold in soil pH are well understood, the threshold has not been quantified at the global scale, where the influence of climate may be confounded by the effects of topography and mineralogy. Here we evaluate the global relationship between water balance and soil pH by extracting a spatially random sample (n = 20,000) from an extensive compilation of 60,291 soil pH measurements. We show that there is an abrupt transition from alkaline to acid soil pH that occurs at the point where mean annual precipitation begins to exceed mean annual potential evapotranspiration. We evaluate deviations from this global pattern, showing that they may result from seasonality, climate history, erosion and mineralogy. These results demonstrate that climate creates a nonlinear pattern in soil solution chemistry at the global scale; they also reveal conditions under which soils maintain pH out of equilibrium with modern climate.

  11. Simple water balance model for estimating runoff at different spatial and temporal scales

    NASA Astrophysics Data System (ADS)

    Schaake, John C.; Koren, Victor I.; Duan, Qing-Yun; Mitchell, Kenneth; Chen, Fei

    1996-03-01

    A parametric water balance model was developed based on statistical averaging of the main hydrological processes. The model has a two-layer structure with both a physical and statistical basis for the model parameters. It was developed to fill a need for models with a small number of parameters and of intermediate complexity between a one-parameter simple bucket and more complex hydrologically oriented models with many parameters such as the Sacramento model. The focus was to improve the representation of runoff relative to the simple bucket without introducing the full complexity of the Sacramento model. The model was designed to operate over a range of time steps to facilitate coupling to an atmospheric model. The model can be used for catchment scale simulations in hydrological applications and for simple representation of runoff in coupled atmospheric/hydrological models. An important role for the simple water balance (SWB) model is to assist in understanding how much complexity in representing land surface processes is needed and can be supported with available data to estimate model parameters. The model is tested using rainfall, runoff, and surface meteorological data for three catchments from different climate regimes. Model performance is compared to performance of a simple bucket model, the Sacramento model, and the Oregon State University land surface model. Finally, a series of tests were conducted to evaluate the sensitivity of SWB performance when it is operated at time steps different from the time step for which it was calibrated.

  12. Identifying streamgage networks for maximizing the effectiveness of regional water balance modeling

    NASA Astrophysics Data System (ADS)

    Fry, L. M.; Hunter, T. S.; Phanikumar, M. S.; Fortin, V.; Gronewold, A. D.

    2013-05-01

    One approach to regional water balance modeling is to constrain rainfall-runoff models with a synthetic regionalized hydrologic response. For example, the Large Basin Runoff Model (LBRM), a cornerstone of hydrologic forecasting in the Laurentian Great Lakes basin, was calibrated to a synthetic discharge record resulting from a drainage area ratio method (ARM) for extrapolating beyond gaged areas. A challenge of such approaches is the declining availability of observations for development of synthetic records. To advance efficient use of the declining gage network in the context of regional water balance modeling, we present results from an assessment of ARM. All possible combinations of "most-downstream" gages were used to simulate runoff at the gaged outlet of Michigan's Clinton River watershed in order to determine the influence of gages' drainage area and other physical characteristics on model skill. For nearly all gage combinations, ARM simulations resulted in good model skill. However, the gages' catchment area relative to that of the outlet's catchment is not an unquestionable predictor of model performance. Results indicate that combinations representing less than 30% of the total catchment area (less than 10% in some cases) can provide very good discharge simulations, but that similarity of the gaged catchments' developed and cultivated area, stream density, and permeability relative to the outlet's catchment is also important for successful simulations. Recognition of thresholds on the relationship between the number of gages and their relative value in simulating flow over large area provides an opportunity for improving historical records for regional hydrologic modeling.

  13. 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.

  14. Water balance creates a threshold in soil pH at the global scale

    NASA Astrophysics Data System (ADS)

    Slessarev, E. W.; Lin, Y.; Bingham, N. L.; Johnson, J. E.; Dai, Y.; Schimel, J. P.; Chadwick, O. A.

    2016-12-01

    Soil pH regulates the capacity of soils to store and supply nutrients, and thus contributes substantially to controlling productivity in terrestrial ecosystems. However, soil pH is not an independent regulator of soil fertility—rather, it is ultimately controlled by environmental forcing. In particular, small changes in water balance cause a steep transition from alkaline to acid soils across natural climate gradients. Although the processes governing this threshold in soil pH are well understood, the threshold has not been quantified at the global scale, where the influence of climate may be confounded by the effects of topography and mineralogy. Here we evaluate the global relationship between water balance and soil pH by extracting a spatially random sample (n = 20,000) from an extensive compilation of 60,291 soil pH measurements. We show that there is an abrupt transition from alkaline to acid soil pH that occurs at the point where mean annual precipitation begins to exceed mean annual potential evapotranspiration. We evaluate deviations from this global pattern, showing that they may result from seasonality, climate history, erosion and mineralogy. These results demonstrate that climate creates a nonlinear pattern in soil solution chemistry at the global scale; they also reveal conditions under which soils maintain pH out of equilibrium with modern climate.

  15. A decade of changing surface energy balance components over a large water region

    NASA Astrophysics Data System (ADS)

    Petchprayoon, Pakorn; Blanken, Peter D.; Hussein, Khalid; Abdalati, Waleed; Lawavirotwong, Siam

    2016-10-01

    This study has investigated the physical processes of energy exchange between the water surface and atmosphere over Lake Huron. The four components of surface energy balance, including net radiation, latent heat, sensible heat, and heat storage, were estimated using the eleven years (2002-2012) daily MODIS data together with in-situ measurements. Good agreement was found between the seasonal turbulent heat fluxes calculated from satellite data and those from the direct measurements (eddy covariance method) with correlation coefficients of 0.94 and 0.95 for sensible heat and latent heat, respectively. There were temporal, spatial heterogeneities, and strong seasonal pattern for all of the four components, which were very high in summer and low in winter for net radiation and heat storage. In contrast, latent heat and sensible heat were very high in the winter and very low in the summer. Trend analysis revealed long term changes for each of the energy balance components, particularly the increase in latent heat which was equivalent to evaporation rate of 0.017 mm m-2 per year, indicating that lake evaporation increased by 0.19 mm m-2 over the eleven years observation period. This was possibly a result of a smaller amount of over lake ice cover and an increase in surface water temperature of Lake Huron.

  16. Water Balance Map of Norway Based On A Distributed Hydrological Model

    NASA Astrophysics Data System (ADS)

    Beldring, S.; Engeland, K.; Roald, L. A.; Sælthun, N. R.

    Water balance maps of Norway for the period 1961-1990 have been produced with a distributed hydrological model. The model applies regional parameters conditioned on catchment characteristics. As this models must consider the relationship between climate and land surface hydrological processes everywhere it must account for the water balance of ungauged areas. Since data are generally not available to calibrate a model for this task in the same way as catchment models, its parameters must be estimated using available hydrological data and information about land surface properties. The structure of this model must be geographically transferable, and its parameters must be derived from knowledge of physical characteristics of the landscape. A distributed HBV-model using 1 km2 grid cells and daily time step was calibrated against monthly runoff data from 141 catchments located in different parts of Norway. Model parameters were conditioned on land use data and digital elevation data. These parameter sets were applied in 43 independent catchments in order to evaluate model performance. The model was run for the entire land surface of Norway in order to determine average yearly runoff for the period 1961-1990. Finally, a river routing procedure based on the kinematic wave approximation was inserted in the model. Daily runoff at the outlet of different subcatchments of river Glomma upstreams Hummelvoll (2411 km2) were calculated and compared to observed data.

  17. Poplar plantation has the potential to alter the water balance in semiarid Inner Mongolia.

    PubMed

    Wilske, Burkhard; Lu, Nan; Wei, Long; Chen, Shiping; Zha, Tonggang; Liu, Chenfeng; Xu, Wenting; Noormets, Asko; Huang, Jianhui; Wei, Yafen; Chen, Jun; Zhang, Zhiqiang; Ni, Jian; Sun, Ge; Guo, Kirk; McNulty, Steve; John, Ranjeet; Han, Xingguo; Lin, Guanghui; Chen, Jiquan

    2009-06-01

    Poplar plantation is the most dominant broadleaf forest type in northern China. Since the mid-1990s plantation was intensified to combat desertification along China's northwestern border, i.e., within Inner Mongolia (IM). This evoked much concern regarding the ecological and environmental effects on areas that naturally grow grass or shrub vegetation. To highlight potential consequences of large-scale poplar plantations on the water budget within semiarid IM, we compared the growing season water balance (evapotranspiration (ET) and precipitation (PPT)) of a 3-yr old poplar plantation (Kp(3)) and a natural shrubland (Ks) in the Kubuqi Desert in western IM, and a 6-yr old poplar plantation (Bp(6)) growing under sub-humid climate near Beijing. The results showed that, despite 33% lower PPT at Kp(3), ET was 2% higher at Kp(3) (228 mm) as compared with Ks (223 mm) in May-September 2006. The difference derived mainly from higher ET at the plantation during drier periods of the growing season, which also indicated that the poplars must have partly transpired groundwater. Estimated growing season ET at Bp(6) was about 550 mm and more than 100% higher than at Kp(3). It is estimated that increases in leaf area index and net radiation at Kp(3) provide future potential for the poplars in Kubuqi to exceed the present ET and ET of the natural shrubland by 100-200%. These increases in ET are only possible through the permanent use of groundwater either directly by the trees or through increased irrigation. This may significantly change the water balance in the area (e.g., high ET at the cost of a reduction in the water table), which renders large-scale plantations a questionable tool in sustainable arid-land management.

  18. Wind speed effects on leaf energy balance, transpiration and water use efficiency

    NASA Astrophysics Data System (ADS)

    Schymanski, S. J.; Or, D.

    2014-12-01

    Transpiration and heat exchange rates by plant leaves involve coupled physiological processes of significant ecohydrological importance. Prediction of the effects of changing environmental conditions such as irradiance, temperature, humidity and wind speed requires a thorough understanding of these processes. The common assumption that leaf temperature equals air temperature may introduce significant bias into estimates of transpiration rates and water use efficiency (WUE, the amount of carbon gained by photosynthesis per unit of water lost by transpiration). Theoretical considerations and observations suggest that leaf temperatures may deviate substantially from air temperature under typical environmental conditions, leading to greatly modified transpiration rates compared to isothermal conditions. In particular, effects of wind on gas exchange must consider feedbacks with leaf temperature. Systematic quantification of the effects of wind speed on leaf heat and gas exchange rates yield some surprising insights. We found a range of conditions where increased wind speed can suppress transpiration rates. The result reflects unintuitive feedbacks between sensible heat flux, leaf temperature, leaf-to-air vapour pressure deficit and latent heat flux. Modelling results suggest that with high wind speeds the same leaf conductance (for water vapour and carbon dioxide) can be maintained with less evaporative losses. This leads to positive relation between water use efficiency and wind speed across a wide range of conditions. The presentation will report results from a lab experiment allowing separation of the different leaf energy balance components under fully controlled conditions (wind speed, temperature, humidity, irradiance) and put them into perspective with a detailed leaf energy balance model and the commonly used Penman-Monteith equation.

  19. Assessment of Early Season Agricultural Drought Through Land Surface Water Index (lswi) and Soil Water Balance Model

    NASA Astrophysics Data System (ADS)

    Chandrasekar, K.; Sesha Sai, M. V. R.; Behera, G.

    2011-08-01

    An attempt was made to address the early season agriculture drought, by monitoring the surface soil wetness during 2010 cropping seasons in the states of Andhra Pradesh and Tamil Nadu. Short Wave Infrared (SWIR) based Land Surface Water Index (LSWI) and Soil Water Balance (SWB) model using inputs from remote sensing and ancillary data were used to monitor early season agriculture drought. During the crop season, investigation was made on LSWI characteristics and its response to the rainfall. It was observed that the Rate of Increase (RoI) of LSWI was the highest during the fortnights when the onset of monsoon occurred. The study showed that LSWI is sensitive to the onset of monsoon and initiation of cropping season. The second part of this study attempted to develop a simple book keeping - bucket type - water tight soil water balance model to derive the top 30cm profile soil moisture using climatic, soil and crop parameters as the basic inputs. Soil moisture derived from the model was used to compute the Area Conducive for Sowing (ACS) during the sowing window of the cropping season. The soil moisture was validated spatially and temporally with the ground observed soil moisture values. The ACS was compared with the RoI of LSWI. The results showed that the RoI was high during the sowing window whenever the ACS was greater than 50% of the district area. The observation was consistent in all the districts of the two states. Thus the analysis revealed the potential of LSWI for early season agricultural drought management.

  20. 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.

  1. 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.

  2. 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.

  3. Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment and classification

    NASA Astrophysics Data System (ADS)

    Weiskel, P. K.; Wolock, D. M.; Zarriello, P. J.; Vogel, R. M.; Levin, S. B.; Lent, R. M.

    2014-03-01

    Runoff-based indicators of terrestrial water availability are appropriate for humid regions, but have tended to limit our basic hydrologic understanding of drylands - the dry-sub-humid, semi-arid, and arid regions which presently cover nearly half of the global land surface. In response, we introduce an indicator framework that gives equal weight to humid and dryland regions, accounting fully for both vertical (precipitation + evapotranspiration) and horizontal (groundwater + surface-water) components of the hydrologic cycle in any given location - as well as fluxes into and out of landscape storage. We apply the framework to a diverse hydroclimatic region (the conterminous USA), using a distributed water-balance model consisting of 53 400 networked landscape hydrologic units. Our model simulations indicate that about 21% of the conterminous USA either generated no runoff or consumed runoff from upgradient sources on a mean-annual basis during the 20th century. Vertical fluxes exceeded horizontal fluxes across 76% of the conterminous area. Long-term average total water availability (TWA) during the 20th century, defined here as the total influx to a landscape hydrologic unit from precipitation, groundwater, and surface water, varied spatially by about 400 000-fold, a range of variation ~100 times larger than that for mean-annual runoff across the same area. The framework includes, but is not limited to classical, runoff-based approaches to water-resource assessment. It also incorporates and re-interprets the green-blue water perspective now gaining international acceptance. Implications of the new framework for hydrologic assessment and classification are explored.

  4. Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management

    NASA Astrophysics Data System (ADS)

    Weiskel, P. K.; Wolock, D. M.; Zarriello, P. J.; Vogel, R. M.; Levin, S. B.; Lent, R. M.

    2014-10-01

    Runoff-based indicators of terrestrial water availability are appropriate for humid regions, but have tended to limit our basic hydrologic understanding of drylands - the dry-subhumid, semiarid, and arid regions which presently cover nearly half of the global land surface. In response, we introduce an indicator framework that gives equal weight to humid and dryland regions, accounting fully for both vertical (precipitation + evapotranspiration) and horizontal (groundwater + surface-water) components of the hydrologic cycle in any given location - as well as fluxes into and out of landscape storage. We apply the framework to a diverse hydroclimatic region (the conterminous USA) using a distributed water-balance model consisting of 53 400 networked landscape hydrologic units. Our model simulations indicate that about 21% of the conterminous USA either generated no runoff or consumed runoff from upgradient sources on a mean-annual basis during the 20th century. Vertical fluxes exceeded horizontal fluxes across 76% of the conterminous area. Long-term-average total water availability (TWA) during the 20th century, defined here as the total influx to a landscape hydrologic unit from precipitation, groundwater, and surface water, varied spatially by about 400 000-fold, a range of variation ~100 times larger than that for mean-annual runoff across the same area. The framework includes but is not limited to classical, runoff-based approaches to water-resource assessment. It also incorporates and reinterprets the green- and blue-water perspective now gaining international acceptance. Implications of the new framework for several areas of contemporary hydrology are explored, and the data requirements of the approach are discussed in relation to the increasing availability of gridded global climate, land-surface, and hydrologic data sets.

  5. 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.

  6. Water balance and renal function in two species of African lungfish Protopterus dolloi and Protopterus annectens.

    PubMed

    Patel, Monika; Iftikar, Fathima I; Smith, Richard W; Ip, Yuen K; Wood, Chris M

    2009-02-01

    The basic physiology of water balance and kidney function was characterized in two species of African lungfish, Protopterus dolloi and Protopterus annectens. Diffusive water efflux rate constants were low (0.13 h(-1)-0.38 h(-1) in various series) relative to values in freshwater teleost fish. Efflux rate constants increased approximately 3-fold after feeding in both species, and were greatly decreased after 8 months terrestrialization (P. dolloi only tested). Urine flow rates (UFR, 3.9-5.2 mL kg(-1) h(-1)) and glomerular filtration rates (GFR, 6.6-9.3 mL kg(-1) h(-1)) were quite high relative to values in most freshwater teleosts. However urinary ion excretion rates were low, with net re-absorption of >99% Na(+), >98% Cl(-), and >78% Ca(2+) from the primary filtrate, comparable to teleosts. Net water re-absorption was significantly greater in P. dolloi (56%) than in P. annectens (23%). We conclude that renal function in lungfish is similar to that in other primitive freshwater fish, but there is an interesting dichotomy between diffusive and osmotic permeabilities. Aquatic lungfish have low diffusive water permeability, an important pre-adaptation to life on land, and in accord with greatly reduced gill areas and low metabolic rates. However osmotic permeability is high, 4-12 times greater than diffusive permeability. A role for aquaporins in this dichotomy is speculated.

  7. Water supply and demand remain balanced during leaf acclimation of Nothofagus cunninghamii trees.

    PubMed

    Brodribb, Timothy J; Jordan, Gregory J

    2011-10-01

    Higher leaf vein density (D(vein) ) enables higher rates of photosynthesis because enhanced water transport allows higher leaf conductances to CO(2) and water. If the total cost of leaf venation rises in proportion to the density of minor veins, the most efficient investment in leaf xylem relative to photosynthetic gain should occur when the water transport capacity of the leaf (determined by D(vein) ) matches potential transpirational demand (determined by stomatal size and density). We tested whether environmental plasticity in stomatal density (D(stomata) ) and D(vein) were linked in the evergreen tree Nothofagus cunninghamii to achieve a balance between liquid and gas phase water conductances. Two sources of variation were examined; within-tree light acclimation, and differences in sun leaves among plants from ecologically diverse populations. Strong, linear correlations between D(vein) and D(stomata) were found at all levels of comparison. The correlations between liquid- and vapour-phase conductances implied by these patterns of leaf anatomy were confirmed by direct measurement of leaf conductance in sun and shade foliage of an individual tree. • Our results provide strong evidence that the development of veins and stomata are coordinated so that photosynthetic yield is optimized relative to carbon investment in leaf venation.

  8. Hydraulic conductivity, photosynthesis and leaf water balance in six evergreen woody species from fall to winter.

    PubMed

    Taneda, Haruhiko; Tateno, Masaki

    2005-03-01

    To confirm that freeze-thaw embolism is a primary stress for evergreen woody species in winter, hydraulic conductivity, photosynthesis and leaf water potential were measured during fall and winter in trees growing in a cool temperate zone (Nikko) and in a warm temperate zone (Tokyo). We examined two evergreen conifers that naturally occur in the cool temperate zone (Abies firma Siebold & Zucc. and Abies homolepis Siebold & Zucc.), and four evergreen broad-leaved woody species that are restricted to the warm temperate zone (Camellia japonica L., Cinnamomum camphora (L.) J. Presl, Ilex crenata Thunb. and Quercus myrsinaefolia Blume). In Tokyo, where no freeze-thaw cycles of xylem sap occurred, hydraulic conductivity, photosynthesis and water balance remained constant during the experimental period. In Nikko, where there were 38 daily freeze-thaw cycles by February, neither of the tracheid-bearing evergreen conifers showed xylem embolism or leaf water deficits. Similarly, the broad-leaved evergreen trees with small-diameter vessels did not exhibit severe embolism or water deficits and maintained CO(2) assimilation even in January. In contrast, the two broad-leaved evergreen trees with large-diameter vessels showed significantly reduced hydraulic conductivity and shoot die-back in winter. We conclude that freeze-thaw embolism restricts evergreen woody species with large-diameter vessels to the warm temperate zone, whereas other stresses limit the distribution of broad-leaved trees, that have small-diameter vessels, but which are restricted to the warm temperate zone.

  9. Energy balance of a high marsh on the Texas Gulf Coast: Effect of water availability

    NASA Astrophysics Data System (ADS)

    Heilman, J. L.; Heinsch, F. A.; Cobos, D. R.; McInnes, K. J.

    2000-09-01

    The supply of water to the Nueces River Delta near Corpus Christi, Texas, and its estuarine marshes is limited by low tidal ranges in the Gulf of Mexico and by channelization of the Nueces River which restricts freshwater inflow. Micrometeorological measurements were made at the upper end (high marsh) of the delta to determine how daily and seasonal changes in the surface energy balance were affected by availability of water. The marsh consists of shallow ponds interconnected by narrow channels, and elevated areas containing emergent vegetation. During the spring and fall when ponds were flooded, latent and sensible heat flux averaged 67% and 30%, respectively, of net radiation. In the summer when ponds dried, energy partitioning was reversed with sensible heat flux accounting for 65% of net radiation and latent heat accounting for 27%. When ponds were flooded, heat storage in the water column was the major component of storage heat flux. When ponds dried, storage heat flux was controlled by sediment water content, largely through its effect on thermal diffusivity. The ratio of actual to equilibrium evaporation averaged 0.7 in the spring and fall, and 0.3 in the summer, indicating that the marsh behaved more like a dryland ecosystem than a wetland.

  10. 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.

  11. Investigating the terrestrial-atmospheric water balance for the Tana River basin, East Africa

    NASA Astrophysics Data System (ADS)

    Kerandi, Noah; Laux, Patrick; Arnault, Joel; Kunstmann, Harald

    2016-04-01

    The fully coupled atmospheric-hydrological WRF-Hydro modeling system is applied to the Tana River basin (TRB) in East Africa for the period 2011-2014 in order to analyze the terrestrial-atmospheric water balance components and their feedback mechanisms. The outputs from the fully coupled modeling system are compared to those of the WRF stand-alone model. The study area encompasses the Mathioya-Sagana subcatchment (3279 km²) in the upper TRB. Our model set up consists of two domains at 25 km and 5 km horizontal resolution covering East Africa and the study area, respectively. The WRF-Hydro inner domain is enhanced with hydrological routing at a 500 m horizontal grid resolution. The simulated monthly precipitation over the subcatchment compared with the Tropical Rainfall Measuring Mission (TRMM) satellite data gives an overall correlation coefficient of 0.8/0.7 for fully coupled/stand-alone model and a mean absolute error (MAE) of 1.5 mm/day for both models for the entire simulation period. Overall the models yield more annual total precipitation compared to TRMM. The two models are drier during the March, April, May (MAM) season and wetter during the October, November, December (OND) season. Compared to observation stations, both modeling systems provide a correlation coefficient of 0.6 for precipitation. The simulated and observed discharges at the Tana Rukanga gauge, located in the subcatchment, exhibit a correlation coefficient of 0.5 at daily resolution. The WRF-Hydro also overestimates the cumulated discharge (2011-2014) by about 50 %. The analysis of the atmospheric water balance in both WRF and WRF-Hydro simulation reveals a positive moisture divergence during the MAM and OND rainy seasons. Precipitation recycling and efficiency measures derived from the atmospheric water budget are also investigated.

  12. 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.

  13. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 2000-01 balance years

    USGS Publications Warehouse

    Krimmel, Robert M.

    2002-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington, to determine the winter and net balances for the 2000 and 2001 balance years. In 2000, the winter balance, averaged over the glacier, was 3.32 meters, and the net balance was 0.38 meters. The winter balance was the ninth highest since the record began in 1959. The net balance was greater than 33 of the 41 years since 1959. In 2001, the winter balance was 1.90 meters, and net balance was -1.57 meters. The winter balance was lower than all but 4 years since 1959, and the net balance was more negative than all but 5 other years. Runoff was measured from the glacier basin and an adjacent non-glacierized basin. Air temperature, precipitation, humidity, wind speed and solar radiation were measured nearby. Ice displacements were measured for the 1998-2001 period.

  14. Estimating the saline springs component in the solute and water balance of Lake Kinneret, Israel

    NASA Astrophysics Data System (ADS)

    Rimmer, Alon; Gal, Gideon

    2003-12-01

    The relatively high salinity of Lake Kinneret, Israel (190-350 ppm Cl -) is a result of the activity of saline springs located at the bottom of the lake. Their subsurface location inhibits direct monitoring of their fluxes. The objective of this work is to characterize the monthly ground water flow and salinity of the unmonitored saline springs over a long-term period, and to find a functional relationship between deriving variables and these monthly discharges. Results of the long-term evaluation of the unmonitored saline springs activity, are intended to help distinguish between two competing models ('gravity driven flow' (GFM) and 'self potential' models), which were proposed as the mechanism of the Lake Kinneret saline springs. The monthly solute and water balance of 32 consecutive years (1968-2001) was calculated, in which the contribution of the saline springs was considered as the residual. Error analyses were conducted for both the water and the solute residuals, and constraints were used to calculate a better, physically based time series representing the unmonitored saline springs activity. The calculated time-series of water and solute discharge from the springs were used to find the functional relationship with the lake level. It was found that there was an increase of water and solute fluxes to the lake at periods of high lake level. We concluded that the results are in agreement with the proposed GFM: high fluxes of ground water to the lake, and high leaching of solute are the result of rainy seasons, which usually cause high lake levels as well.

  15. 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.

  16. Plant cover and water balance in gravel admixtures at an arid waste-burial site

    SciTech Connect

    Waugh, W.J.; Thiede, M.E.; Bates, D.J.

    1994-07-01

    Isolation of radioactive waste buried in unsaturated zones will require long-term control of recharge and erosion. Soil covers control recharge at and sites by storing rainwater close enough to the surface to be removed by evapotranspiration. Surface layers of rock or gravel control erosion at sites with sparse vegetation, but can also alter plant habitat and cause recharge through interred waste. As an alternative, gravel mixed into the uppermost soil law may control erosion ever the king-term better than surface gravel layers. Gravel admixtures may also not influence plant establishment or sod water balance in waste-site covers. The interactive effects of gravel admixture concentration, vegetation, and precipitation on soil water content and plant cover were measured at the US Department of Energy`s Hanford Site. Results support use of a combination of vegetation and gravel admixtures for erosion control. Vegetation seasonally depleted root zone water storage to about 6.5 volume % regardless of precipitation amount or the presence of gravel admixture amendments. In contrast, yearly increases in soil water storage as deep as 225 cm in plots without vegetation may be a leading indicator of recharge. The composition and abundance of vegetation changed over time and with precipitation amount, but was not influenced by gravel amendments. Seeded wheatgrasses [Agropyron sibericum Wilde and Agropyron dasystachyum (Hook.) Scribn.] established only when irrigated with twice average precipitation, but persisted after the irrigation ceased. Cheatgrass (Bromus tectorum L.) and Russian thistle (Salsola kali L.) colonized areas receiving both irrigation and ambient precipitation. Stands with wheatgrasses extracted water more rapidly and depleted soil water to lower levels than cheatgrass-dominated stands. Increases in gravel cover and near-surface gravel concentrations after 5 yr were evidence of the formation of a protective gravel veneer. 44 refs., 8 figs., 2 tabs.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Manus Water Isotope Investigation Field Campaign Report

    SciTech Connect

    Conroy, Jessica L; Cobb, Kim M; Noone, David

    2016-03-01

    The objective of this field campaign was to investigate climatic controls on the stable isotopic composition of water vapor, precipitation, and seawater in the western tropical Pacific. Simultaneous measurements of the stable isotopic composition of vapor and precipitation from April 28 to May 8, 2013, at the Manus Tropical Western Pacific Atmospheric Radiation Measurement site, provided several key insights into the nature of the climate signal archived in precipitation and vapor isotope ratios. We observed a large shift from lower to higher isotopic values in vapor and precipitation because of the passage of a mesoscale convective system west of the site and a transition from a regional stormy period into a more quiescent period. During the quiescent period, the stable isotopic composition of vapor and precipitation indicated the predominance of oceanic evaporation in determining the isotopic composition of boundary-layer vapor and local precipitation. There was not a consistent relationship between intra-event precipitation amount at the site and the stable isotopic composition of precipitation, thus challenging simplified assumptions about the isotopic “amount effect” in the tropics on the time scale of individual storms. However, some storms did show an amount effect, and deuterium excess values in precipitation had a significant relationship with several meteorological variables, including precipitation, temperature, relative humidity, and cloud base height across all measured storms. The direction of these relationships points to condensation controls on precipitation deuterium excess values on intra-event time scales. The relationship between simultaneous measurements of vapor and precipitation isotope ratios during precipitation events indicates the ratio of precipitation-to-vapor isotope ratios can diagnose precipitation originating from a vapor source unique from boundary-layer vapor and rain re-evaporation.

  3. 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

  4. Water balance monitoring for two bioretention gardens in Omaha, Nebraska, 2011–14

    USGS Publications Warehouse

    Strauch, Kellan R.; Rus, David L.; Holm, Kent E.

    2016-01-29

    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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. Multiobjective calibration and sensitivity of a distributed land surface water and energy balance model

    NASA Astrophysics Data System (ADS)

    Houser, Paul R.; Gupta, Hoshin V.; Shuttleworth, W. James; Famiglietti, James S.

    2001-12-01

    The feasibility of using spatially distributed information to improve the predictive ability of a spatially distributed land surface water and energy balance model (LSM) was explored at the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) Walnut Gulch Experimental Watershed in southeastern Arizona. The inclusion of spatially variable soil and vegetation information produced unrealistic simulations that were inconsistent with observations, which was likely an artifact of both discretely assigning a single set of parameters to a given area and inadequate knowledge of spatially varying parameter values. Because some of the model parameters were not measured or are abstract quantities a multiobjective least squares strategy was used to find catchment averaged parameter values that minimize the prediction error of latent heat flux, soil heat flux, and surface soil moisture. This resulted in a substantial improvement in the model's spatially distributed performance and yielded valuable insights into the interaction and optimal selection of model parameters.

  10. The U.S. Geological Survey Monthly Water Balance Model Futures Portal

    USGS Publications Warehouse

    Bock, Andy

    2017-03-16

    Simulations of future climate suggest profiles of temperature and precipitation may differ significantly from those in the past. These changes in climate will likely lead to changes in the hydrologic cycle. As such, natural resource managers are in need of tools that can provide estimates of key components of the hydrologic cycle, uncertainty associated with the estimates, and limitations associated with the climate forcing data used to estimate these components. To help address this need, the U.S. Geological Survey Monthly Water Balance Model Futures Portal (https://my.usgs.gov/mows/) provides a user friendly interface to deliver hydrologic and meteorological variables for monthly historic and potential future climatic conditions across the continental United States.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. Well-balanced high-order centered schemes on unstructured meshes for shallow water equations with fixed and mobile bed

    NASA Astrophysics Data System (ADS)

    Canestrelli, Alberto; Dumbser, Michael; Siviglia, Annunziato; Toro, Eleuterio F.

    2010-03-01

    In this paper, we study the numerical approximation of the two-dimensional morphodynamic model governed by the shallow water equations and bed-load transport following a coupled solution strategy. The resulting system of governing equations contains non-conservative products and it is solved simultaneously within each time step. The numerical solution is obtained using a new high-order accurate centered scheme of the finite volume type on unstructured meshes, which is an extension of the one-dimensional PRICE-C scheme recently proposed in Canestrelli et al. (2009) [5]. The resulting first-order accurate centered method is then extended to high order of accuracy in space via a high order WENO reconstruction technique and in time via a local continuous space-time Galerkin predictor method. The scheme is applied to the shallow water equations and the well-balanced properties of the method are investigated. Finally, we apply the new scheme to different test cases with both fixed and movable bed. An attractive future of the proposed method is that it is particularly suitable for engineering applications since it allows practitioners to adopt the most suitable sediment transport formula which better fits the field data.

  16. 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.

  17. 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

  18. Meeting the challenges of on-host and off-host water balance in blood-feeding arthropods

    PubMed Central

    Benoit, Joshua B.; Denlinger, David L.

    2010-01-01

    In this review, we describe water balance requirements of blood-feeding arthropods, particularly contrasting dehydration tolerance during the unfed, off-host state and the challenges of excess water that accompany receipt of the bloodmeal. Most basic water balance characteristics during the off-host stage are applicable to other terrestrial arthropods, as well. A well-coordinated suite of responses enable arthropods to conserve water resources, enhance their desiccation tolerance, and increase their water supplies by employing a diverse array of molecular, structural and behavioral responses. Water loss rates during the off-host phase are particularly useful for generating a scheme to classify vectors according to their habitat requirements for water, thus providing a convenient tool with potential predictive power for defining suitable current and future vector habitats. Blood feeding elicits an entirely different set of challenges as the vector responds to overhydration by quickly increasing its rate of cuticular water loss and elevating the rate of diuresis to void excess water and condense the bloodmeal. Immature stages that feed on blood normally have a net increase in water content at the end of a blood-feeding cycle, but in adults the water content reverts to the prefeeding level when the cycle is completed. Common themes are evident in diverse arthropods that feed on blood, particularly the physiological mechanisms used to respond to the sudden influx of water as well as the mechanisms used to counter water shortfalls that are encountered during the nonfeeding, off-host state. PMID:20206630

  19. The effect of using a geotextile in a monolithic (evapotranspiration) alternative landfill cover on the resulting water balance.

    PubMed

    Sun, Jianlei; Yuen, Samuel T S; Fourie, Andy B

    2010-11-01

    This paper examines the potential effects of a geotextile layer used in a lysimeter pan experiment conducted in a monolithic (evapotranspiration) soil cover trial on its resulting water balance performance. The geotextile was added to the base of the lysimeter to serve as a plant root barrier in order to delineate the root zone depth. Both laboratory data and numerical modelling results indicated that the geotextile creates a capillary barrier under certain conditions and retains more water in the soil above the soil/geotextile interface than occurs without a geotextile. The numerical modelling results also suggested that the water balance of the soil cover could be affected by an increase in plant transpiration taking up this extra water retained above the soil/geotextile interface. This finding has a practical implication on the full-scale monolithic cover design, as the absence of the geotextile in the full-scale cover may affect the associated water balance and hence cover performance. Proper consideration is therefore required to assess the final monolithic cover water balance performance if its design is based on the lysimeter results.

  20. Simulations of soil water balance in an irrigated district of Southern Italy

    NASA Astrophysics Data System (ADS)

    Ventrella, D.; Castellini, M.; Giglio, L.; di Giacomo, E.; Lopez, R.

    2009-04-01

    The available approaches for predicting the soil hydraulic functions include direct methods, using laboratory and field experiments, and indirect methods, such as the application of pedo-transfer functions or inverse methods. This last approach consists of a non-linear estimation of the soil hydraulic parameters by minimising the residuals between observed and simulated values of variables, such as the volumetric water content (theta) and the soil water pressure head (h). Numerical models are increasingly being used to simulate water and solute movement in the vadose zone for a variety of applications in research and soil/water management. While a large number of models of various complexity have been developed over the years, relatively few have been tested under field conditions. Soil water flow in physically-based models is described by Richards' equation. Application of this equation requires knowledge of the two functions: the soil water retention, theta(h), and the hydraulic conductivity, K(h). Inverse procedures have been successfully applied to analyse laboratory results using multistep or evaporation methods. During the last years, the application of inverse method is increasing by being applied to field experiments. Recently, several Authors have estimated the effective soil hydraulic function parameters with the inverse method by using evapotranspiration (ET) and soil water content data collected from a lysimeter experiment for a soil cropped with wheat. The objective of this paper is to test different strategies to optimize the simulation of soil water content dynamics for a typical cultivation of water melon (Cuccumis citrullus) for the area of "Arco Jonico Metapontino" located in Basilicata and Puglia regions (Southern Italy). The strategies utilized in the comparison are based on: (i) direct measurements of the theta(h) and the K(h); (ii) utilization of pedotransfer functions starting from textural information and (iii) inverse procedures including

  1. 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 flow. The average flow for the period of study was

  2. Effects of recurrent drought on the water balance and biomass production of irrigated mountain grassland

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Besides rising temperatures, climate change is also expected to change precipitation patterns, especially increasing the probability of extreme events like droughts and thunderstorms. In the North Italian region of Trentino/South Tirol, a reduction of rainfalls in spring has been observed in the last decades. A joint project by the European Academy Bozen/Bolzano and the University of Innsbruck analyzed the effects of repeated spring and summer droughts on the water balance, carbon flux and productivity of an irrigated mountain grassland site at 1500 m a.s.l. in the inner-alpine dry area of the Matsch Valley/Vinschgau during the years 2012 and 2013. We anticipated a decrease of soil moisture, evapotranspiration, carbon uptake, and plant growth during drought periods. Soil memory effects, delayed plant development, and changes of vegetation composition were expected long-term effects of periodic water shortage. Water balance was measured continuously with weighing lysimeters (diameter and depth 0.3 m) which were installed in 2011; in addition to lysimeter weight, soil moisture and water potential in 2 depths and the volume of seepage was recorded every ten minutes for each lysimeter. Carbon flux was measured regularly with a canopy chamber eduring the growing season, above-ground biomass and vegetation composition were analyzed after cutting the vegetation twice per year in accordance to local management. To simulate severe droughts, a group of three lysimeters was sheltered from any rainfall and irrigation with a foil tunnel for four to six weeks during the early growth period in spring and again during the regrowth period after the first cut in summer in 2012 and 2013. A control group of three lysimeters remained unsheltered and exposed to rainfall and irrigation. Preliminary results show a clear reduction of soil moisture, evapotranspiration, carbon uptake and biomass in sheltered lysimeters during the drought periods, but a quick recovery afterwards. However

  3. Evaluation of hydrological balance in the eastern Amazon using a terrestrial ecosystem model, and satellite-based evapotranspiration (MODIS) and terrestrial water storage (GRACE)

    NASA Astrophysics Data System (ADS)

    Panday, P. K.; Coe, M. T.; Macedo, M.; Beck, P.

    2013-12-01

    High historical deforestation rates and a rapidly changing agricultural landscape may dramatically alter the energy and water balance of the eastern Amazon basin. Understanding the surface water dynamics and hydrological balance of the region is critical for accurately assessing the historical and potential future impacts of deforestation, land-use change, and land management practices. We examine the water balance of the Xingu river basin by combining the IBIS (Integrated Biosphere Simulator) terrestrial ecosystem model with satellite-based models of evapotranspiration (MOD16) and terrestrial water storage (GRACE). IBIS simulations were forced with prescribed climate to produce modeled evapotranspiration and runoff, which were then compared with MODIS evapotranspiration and observed discharge at Altamira (PA, Brazil). Results from both satellite observations and model simulations support earlier studies demonstrating that dry-season evapotranspiration is higher than wet-season evapotranspiration in the wetter forests of the northern Xingu basin, while the contrary is true in the seasonally dry forests of the southern Xingu. Seasonal variation in modeled soil water storage agrees with the GRACE measurements in both timing and magnitude. Soil moisture anomalies averaged over the Xingu basin suggest that annual changes in soil water storage account for a large part of the interannual variation in observed discharge. Field measurements of discharge and soil moisture in the southern Xingu also support the findings that changes in soil water storage drive inter-annual variations in river discharge. Figure 1. Comparison of observed discharge at Altamira (Pará, Brazil) against MODIS- derived P-E (PCRU-MODISET), IBIS simulated discharge, IBIS (PCRU-ETIBIS), and IBIS (PCRU-ETIBIS- Δ Soil moisture IBIS). The bottom panel shows annual basin precipitation from Climatic Research Unit (CRU) climatological data for the 2000-2008 period

  4. Evapotranspiration from Upper Klamath Lake: Reducing Uncertainty in the Water Balance

    NASA Astrophysics Data System (ADS)

    Stannard, D. I.; Gannett, M. W.; Polette, D.; Cameron, J. M.; Spears, J. M.

    2009-12-01

    The Klamath River basin is a large (~40,600 km2) watershed that straddles the border between southern Oregon and northern California, USA, and drains into the Pacific Ocean. A wide variety of interests has led to intense competition over water allocation in the upper, semi-arid parts of the basin in recent decades. Myriad water impoundments and diversions, wetland drainage, and recent wetland restoration, have complicated the development of resource-management and restoration strategies. An overarching question is how to provide enough water for irrigated agriculture and still preserve adequate stream-flow and wetland habitat for threatened (e.g. coho salmon) and endangered (e.g. Lost River and shortnose suckers) species. In the Upper Klamath Lake region, this hotly debated topic has raised questions about evaporative losses from Upper Klamath Lake, and its wetland marshes. Currently, surface-water outflow from the lake is gauged, but not all of the surface-water inflows are gauged, and net ground-water inflow is estimated. Lake-level management is based on a simplified water budget: NETin - SWout = ΔS, where NETin = SWin + GWnet - ET (called “net inflow”), SWout is measured surface-water outflow, ΔS is measured change in lake storage, SWin is surface-water inflow, GWnet is net ground-water inflow, and ET is evapotranspiration from the lake. Partitioning of NETin is not done routinely, so little is known about magnitudes of the un-gauged inflows, or ET (GWnet is a small term). To help partition NETin into its components, ET has been measured at three locations in Upper Klamath Lake since April, 2008. Two eddy covariance (EC) sites are located in Upper Klamath National Wildlife Refuge, an extensive wetland marsh in the northwest corner of the lake, and one Bowen-ratio energy-balance site is in open water. One EC station is situated in bulrush and the other is in a mixed bulrush, wocus, cattail community. Wetland marsh area is about 1/3 that of open water. The

  5. Variations in surface water-ground water interactions along a headwater mountain stream : comparisons between transient storage and water balance analyses

    USGS Publications Warehouse

    Ward, Adam S.; Payn, Robert A.; Gooseff, Michael N.; McGlynn, Brian L.; Bencala, Kenneth E.; Kelleher, Christa A.; Wondzell, Steven M.; Wagener, Thorsten

    2013-01-01

    The accumulation of discharge along a stream valley is frequently assumed to be the primary control on solute transport processes. Relationships of both increasing and decreasing transient storage, and decreased gross losses of stream water have been reported with increasing discharge; however, we have yet to validate these relationships with extensive field study. We conducted transient storage and mass recovery analyses of artificial tracer studies completed for 28 contiguous 100 m reaches along a stream valley, repeated under four base-flow conditions. We calculated net and gross gains and losses, temporal moments of tracer breakthrough curves, and best fit transient storage model parameters (with uncertainty estimates) for 106 individual tracer injections. Results supported predictions that gross loss of channel water would decrease with increased discharge. However, results showed no clear relationship between discharge and transient storage, and further analysis of solute tracer methods demonstrated that the lack of this relation may be explained by uncertainty and equifinality in the transient storage model framework. Furthermore, comparison of water balance and transient storage approaches reveals complications in clear interpretation of either method due to changes in advective transport time, which sets a the temporal boundary separating transient storage and channel water balance. We have little ability to parse this limitation of solute tracer methods from the physical processes we seek to study. We suggest the combined analysis of both transient storage and channel water balance more completely characterizes transport of solutes in stream networks than can be inferred from either method alone.

  6. Effects of chronic exposure to radiofrequency electromagnetic fields on energy balance in developing rats.

    PubMed

    Pelletier, Amandine; Delanaud, Stéphane; Décima, Pauline; Thuroczy, Gyorgy; de Seze, René; Cerri, Matteo; Bach, Véronique; Libert, Jean-Pierre; Loos, Nathalie

    2013-05-01

    The effects of radiofrequency electromagnetic fields (RF-EMF) on the control of body energy balance in developing organisms have not been studied, despite the involvement of energy status in vital physiological functions. We examined the effects of chronic RF-EMF exposure (900 MHz, 1 V m(-1)) on the main functions involved in body energy homeostasis (feeding behaviour, sleep and thermoregulatory processes). Thirteen juvenile male Wistar rats were exposed to continuous RF-EMF for 5 weeks at 24 °C of air temperature (T a) and compared with 11 non-exposed animals. Hence, at the beginning of the 6th week of exposure, the functions were recorded at T a of 24 °C and then at 31 °C. We showed that the frequency of rapid eye movement sleep episodes was greater in the RF-EMF-exposed group, independently of T a (+42.1 % at 24 °C and +31.6 % at 31 °C). The other effects of RF-EMF exposure on several sleep parameters were dependent on T a. At 31 °C, RF-EMF-exposed animals had a significantly lower subcutaneous tail temperature (-1.21 °C) than controls at all sleep stages; this suggested peripheral vasoconstriction, which was confirmed in an experiment with the vasodilatator prazosin. Exposure to RF-EMF also increased daytime food intake (+0.22 g h(-1)). Most of the observed effects of RF-EMF exposure were dependent on T a. Exposure to RF-EMF appears to modify the functioning of vasomotor tone by acting peripherally through α-adrenoceptors. The elicited vasoconstriction may restrict body cooling, whereas energy intake increases. Our results show that RF-EMF exposure can induce energy-saving processes without strongly disturbing the overall sleep pattern.

  7. A Well-Balanced Central-Upwind Scheme for the 2D Shallow Water Equations on Triangular Meshes

    NASA Technical Reports Server (NTRS)

    Bryson, Steve; Levy, Doron

    2004-01-01

    We are interested in approximating solutions of the two-dimensional shallow water equations with a bottom topography on triangular meshes. We show that there is a certain flexibility in choosing the numerical fluxes in the design of semi-discrete Godunov-type central schemes. We take advantage of this fact to generate a new second-order, central-upwind method for the two-dimensional shallow water equations that is well-balanced. We demonstrate the accuracy of our method as well as its balance properties in a variety of examples.

  8. Water, ice, meteorological, and speed measurements at South Cascade Glacier, Washington, 1999 balance year

    USGS Publications Warehouse

    Krimmel, Robert M.

    2001-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington, to determine the winter and net balances for the 1999 balance year. The 1999 winter snow balance, averaged over the glacier, was 3.59 meters, and the net balance was 1.02 meters. Since the winter balance record began in 1959, only three winters have had a higher winter balance. Since the net balance record began in 1953, only 2 years have had a greater positive net balance than 1999. Runoff was measured from the glacier and an adjacent non-glacierized basin. Air temperature, precipitation, and humidity were measured nearby, and ice speed was measured. This report makes these data available to the glaciological and climatological community.

  9. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 1994 balance year

    USGS Publications Warehouse

    Krimmel, R.M.

    1995-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington to determine the winter and net balances for the 1994 balance year. The 1994 winter balance, averaged over the glacier, was 2.39 meters, and the net balance was -1.60 meters. The winter balance was approximately that of the 1977-94 average winter balance. The net balance was more negative than the 1977-94 average net balance of -1.02 meters. Runoff was measured from the glacier and an adjacent non- glacierized basin. Air temperature, precipitation, barometric pressure, solar radiation, and wind speed were measured nearby. This report makes these data available to the glaciological and climatological community.

  10. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 1995 balance year

    USGS Publications Warehouse

    Krimmel, R.M.

    1996-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington to determine the winter and net balances for the 1995 balance year. The 1995 winter balance, averaged over the glacier, was 2.86 meters, and the net balance was -0.69 meter. The winter balance was approximately 0.5 meter greater than the 1977-94 average winter balance. The net balance was approximately 0.3 meter less negative than the 1977-94 average net balance. Runoff was measured from the glacier and an adjacent non-glacierized basin. Air temperature, precipitation, barometric pressure, solar radiation, and wind speed were measured adjacent to the glacier. This report makes these data available to the glaciological and climatological community.

  11. Water, ice, and meteorological measurements at South Cascade Glacier, Washington, 1996 balance year

    USGS Publications Warehouse

    Krimmel, Robert M.

    1997-01-01

    Winter snow accumulation and summer snow, firn, and ice melt were measured at South Cascade Glacier, Washington to determine the winter and net balances for the 1996 balance year. The 1996 winter balance, averaged over the glacier, was 2.94 meters, and the net balance was 0.10meter. The winter balance was approximately 0.6 meter greater than the 1977-95 average winter balance (2.30 meters). The net balance, which was positive for the first time since 1984, was more than a meter greater than the 1977-95 average net balance (-0.96 meter). The glacier retreated about 15 meters from its 1995 position. Runoff was measured from the glacier and an adjacent non-glacierized basin. Air temperature, precipitation, and barometric pressure were measured nearby. This report makes these data available to the glaciological and climatological community

  12. Mechanical balance laws for fully nonlinear and weakly dispersive water waves

    NASA Astrophysics Data System (ADS)

    Kalisch, Henrik; Khorsand, Zahra; Mitsotakis, Dimitrios

    2016-10-01

    The Serre-Green-Naghdi system is a coupled, fully nonlinear system of dispersive evolution equations which approximates the full water wave problem. The system is known to describe accurately the wave motion at the surface of an incompressible inviscid fluid in the case when the fluid flow is irrotational and two-dimensional. The system is an extension of the well known shallow-water system to the situation where the waves are long, but not so long that dispersive effects can be neglected. In the current work, the focus is on deriving mass, momentum and energy densities and fluxes associated with the Serre-Green-Naghdi system. These quantities arise from imposing balance equations of the same asymptotic order as the evolution equations. In the case of an even bed, the conservation equations are satisfied exactly by the solutions of the Serre-Green-Naghdi system. The case of variable bathymetry is more complicated, with mass and momentum conservation satisfied exactly, and energy conservation satisfied only in a global sense. In all cases, the quantities found here reduce correctly to the corresponding counterparts in both the Boussinesq and the shallow-water scaling. One consequence of the present analysis is that the energy loss appearing in the shallow-water theory of undular bores is fully compensated by the emergence of oscillations behind the bore front. The situation is analyzed numerically by approximating solutions of the Serre-Green-Naghdi equations using a finite-element discretization coupled with an adaptive Runge-Kutta time integration scheme, and it is found that the energy is indeed conserved nearly to machine precision. As a second application, the shoaling of solitary waves on a plane beach is analyzed. It appears that the Serre-Green-Naghdi equations are capable of predicting both the shape of the free surface and the evolution of kinetic and potential energy with good accuracy in the early stages of shoaling.

  13. Spatial variability in water-balance model performance in the conterminous United States

    USGS Publications Warehouse

    Hay, L.E.; McCabe, G.J.

    2002-01-01

    A monthly water-balance (WB) model was tested in 44 river basins from diverse physiographic and climatic regions across the conterminous United States (U.S.). The WB model includes the concepts of climatic water supply and climatic water demand, seasonality in climatic water supply and demand, and soil-moisture storage. Exhaustive search techniques were employed to determine the optimal set of precipitation and temperature stations, and the optimal set of WB model parameters to use for each basin. It was found that the WB model worked best for basins with: (1) a mean elevation less than 450 meters or greater than 2000 meters, and/or (2) monthly runoff that is greater than 5 millimeters (mm) more than 80 percent of the time. In a separate analysis, a multiple linear regression (MLR) was computed using the adjusted R-square values obtained by comparing measured and estimated monthly runoff of the original 44 river basins as the dependent variable, and combinations of various independent variables [streamflow gauge latitude, longitude, and elevation; basin area, the long-term mean and standard deviation of annual precipitation; temperature and runoff; and low-flow statistics (i.e., the percentage of months with monthly runoff that is less than 5 mm)]. Results from the MLR study showed that the reliability of a WB model for application in a specific region can be estimated from mean basin elevation and the percentage of months with gauged runoff less than 5 mm. The MLR equations were subsequently used to estimate adjusted R-square values for 1,646 gauging stations across the conterminous U.S. Results of this study indicate that WB models can be used reliably to estimate monthly runoff in the eastern U.S., mountainous areas of the western U.S., and the Pacific Northwest. Applications of monthly WB models in the central U.S. can lead to uncertain estimates of runoff.

  14. Canopy water balance of windward and leeward Hawaiian cloud forests on Haleakalā, Maui, Hawai'i

    USGS Publications Warehouse

    Giambelluca, Thomas W.; DeLay, John K.; Nullet, Michael A.; Scholl, Martha A.; Gingerich, Stephen B.

    2011-01-01

    The contribution of intercepted cloud water to precipitation at windward and leeward cloud forest sites on the slopes of Haleakalā, Maui was assessed using two approaches. Canopy water balance estimates based on meteorological monitoring were compared with interpretations of fog screen measurements collected over a 2-year period at each location. The annual incident rainfall was 973 mm at the leeward site (Auwahi) and 2550 mm at the windward site (Waikamoi). At the leeward, dry forest site, throughfall was less than rainfall (87%), and, at the windward, wet forest site, throughfall exceeded rainfall (122%). Cloud water interception estimated from canopy water balance was 166 mm year−1 at Auwahi and 1212 mm year−1 at Waikamoi. Annual fog screen measurements of cloud water flux, corrected for wind-blown rainfall, were 132 and 3017 mm for the dry and wet sites respectively. Event totals of cloud water flux based on fog screen measurements were poorly correlated with event cloud water interception totals derived from the canopy water balance. Hence, the use of fixed planar fog screens to estimate cloud water intercepti