WorldWideScience

Sample records for surface flow hydrology

  1. Hydrological land surface modelling

    DEFF Research Database (Denmark)

    Ridler, Marc-Etienne Francois

    Recent advances in integrated hydrological and soil-vegetation-atmosphere transfer (SVAT) modelling have led to improved water resource management practices, greater crop production, and better flood forecasting systems. However, uncertainty is inherent in all numerical models ultimately leading...... temperature are explored in a multi-objective calibration experiment to optimize the parameters in a SVAT model in the Sahel. The two satellite derived variables were effective at constraining most land-surface and soil parameters. A data assimilation framework is developed and implemented with an integrated...... and disaster management. The objective of this study is to develop and investigate methods to reduce hydrological model uncertainty by using supplementary data sources. The data is used either for model calibration or for model updating using data assimilation. Satellite estimates of soil moisture and surface...

  2. Low flow hydrology: a review

    CSIR Research Space (South Africa)

    Smakhtin, VU

    2001-01-10

    Full Text Available The paper intends to review the current status of low-flow hydrology — a discipline which deals with minimum flow in a river during the dry periods of the year. The discussion starts with the analysis of low-flow generating mechanisms operating...

  3. Hydrology and flow forecasting

    NARCIS (Netherlands)

    Vrijling, J.K.; Kwadijk, J.; Van Duivendijk, J.; Van Gelder, P.; Pang, H.; Rao, S.Q.; Wang, G.Q.; Huang, X.Q.

    2002-01-01

    We have studied and applied the statistic model (i.e. MMC) and hydrological models to Upper Yellow River. This report introduces the results and some conclusions from the model. The three models, MMC, MWBM and NAM, have be applied in the research area. The forecasted discharge by the three models

  4. Integrated surface-subsurface water flow modelling of the Laxemar area. Application of the hydrological model ECOFLOW

    International Nuclear Information System (INIS)

    Sokrut, Nikolay; Werner, Kent; Holmen, Johan

    2007-01-01

    Since 2002, the Swedish Nuclear Fuel and Waste Management Co (SKB) performs site investigations in the Simpevarp area, for the siting of a deep geological repository for spent nuclear fuel. The site descriptive modelling includes conceptual and quantitative modelling of surface-subsurface water interactions, which are key inputs to safety assessment and environmental impact assessment. Such modelling is important also for planning of continued site investigations. In this report, the distributed hydrological model ECOFLOW is applied to the Laxemar subarea to test the ability of the model to simulate surface water and near-surface groundwater flow, and to illustrate ECOFLOW's advantages and drawbacks. The ECOFLOW model area is generally characterised by large areas of exposed or shallow bedrock. The ECOFLOW modelling results are compared to previous results produced by MIKE SHE-MIKE 11 and PCRaster-POLFLOW, in order to check whether non-calibrated surface and subsurface water flows computed by ECOFLOW are consistent with these previous results. The analyses include quantification and comparison of inflow and outflow terms of the water balance, as well as analyses of groundwater recharge-discharge patterns. ECOFLOW is used to simulate a one-year non calibrated period, considering seven catchments (including three areas with direct runoff to the sea) within the Laxemar subarea. The modelling results show the ability of the model to produce reasonable results for a model domain including both porous media (Quaternary deposits) and discontinuous media (bedrock). The results demonstrate notable differences in the specific discharge between the considered catchments, with specific discharge values in the range 157-212 mm/year; the lowest value (the Lake Frisksjoen catchment) may however be erroneous due to numerical instability in the model. Overall, these results agree with specific discharge values computed by MIKE SHE-MIKE 11 and PCRaster-POLFLOW (190 and 128-186 mm

  5. Integrated surface-subsurface water flow modelling of the Laxemar area. Application of the hydrological model ECOFLOW

    Energy Technology Data Exchange (ETDEWEB)

    Sokrut, Nikolay; Werner, Kent; Holmen, Johan [Golder Associates AB, Uppsala (Sweden)

    2007-01-15

    Since 2002, the Swedish Nuclear Fuel and Waste Management Co (SKB) performs site investigations in the Simpevarp area, for the siting of a deep geological repository for spent nuclear fuel. The site descriptive modelling includes conceptual and quantitative modelling of surface-subsurface water interactions, which are key inputs to safety assessment and environmental impact assessment. Such modelling is important also for planning of continued site investigations. In this report, the distributed hydrological model ECOFLOW is applied to the Laxemar subarea to test the ability of the model to simulate surface water and near-surface groundwater flow, and to illustrate ECOFLOW's advantages and drawbacks. The ECOFLOW model area is generally characterised by large areas of exposed or shallow bedrock. The ECOFLOW modelling results are compared to previous results produced by MIKE SHE-MIKE 11 and PCRaster-POLFLOW, in order to check whether non-calibrated surface and subsurface water flows computed by ECOFLOW are consistent with these previous results. The analyses include quantification and comparison of inflow and outflow terms of the water balance, as well as analyses of groundwater recharge-discharge patterns. ECOFLOW is used to simulate a one-year non calibrated period, considering seven catchments (including three areas with direct runoff to the sea) within the Laxemar subarea. The modelling results show the ability of the model to produce reasonable results for a model domain including both porous media (Quaternary deposits) and discontinuous media (bedrock). The results demonstrate notable differences in the specific discharge between the considered catchments, with specific discharge values in the range 157-212 mm/year; the lowest value (the Lake Frisksjoen catchment) may however be erroneous due to numerical instability in the model. Overall, these results agree with specific discharge values computed by MIKE SHE-MIKE 11 and PCRaster-POLFLOW (190 and 128

  6. Flow variability and hillslope hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Huff, D D; O' Neill, R V; Emanuel, W R; Elwood, J W; Newbold, J D

    1982-01-01

    Examination of spatial variability of streamflow in headwater areas can provide important insight about factors that influence hillslope hydrology. Detailed observations of variations in stream channel input, based on a tracer experiment, indicate that topography alone cannot explain flow variability. However, determination of changes in channel input on a small spatial scale can provide valuable clues to factors, such as structural geology that control subsurface flows.

  7. A novel algorithm for delineating wetland depressions and mapping surface hydrologic flow pathways using LiDAR data

    Science.gov (United States)

    In traditional watershed delineation and topographic modeling, surface depressions are generally treated as spurious features and simply removed from a digital elevation model (DEM) to enforce flow continuity of water across the topographic surface to the watershed outlets. In re...

  8. Surface Velocities and Hydrology at Engabreen

    DEFF Research Database (Denmark)

    Messerli, Alexandra

    complicates comparisons with other surface-oriented glaciohydrological studies. One major aim of this thesis is to provide a longer record of surface velocity, enabling a more complete understanding of the glacial hydro-mechanical relationship at Engabreen. In order to extend the velocity dataset here, a time...... the lower tongue of Engabreen are analysed in detail alongside the hydro-meteorological time-series. The higher temporal resolution of the GPS allows the effect of short-term hydrological forcings on ice flow to be assessed. Two key events: the spring-speed up event (P1a) and a short-term rain induced event...

  9. The impact of runoff and surface hydrology on Titan's climate

    Science.gov (United States)

    Faulk, Sean; Lora, Juan; Mitchell, Jonathan

    2017-10-01

    Titan’s surface liquid distribution has been shown by general circulation models (GCMs) to greatly influence the hydrological cycle. Simulations from the Titan Atmospheric Model (TAM) with imposed polar methane “wetlands” reservoirs realistically produce many observed features of Titan’s atmosphere, whereas “aquaplanet” simulations with a global methane ocean are not as successful. In addition, wetlands simulations, unlike aquaplanet simulations, demonstrate strong correlations between extreme rainfall behavior and observed geomorphic features, indicating the influential role of precipitation in shaping Titan’s surface. The wetlands configuration is, in part, motivated by Titan’s large-scale topography featuring low-latitude highlands and high-latitude lowlands, with the implication being that methane may concentrate in the high-latitude lowlands by way of runoff and subsurface flow. However, the extent to which topography controls the surface liquid distribution and thus impacts the global hydrological cycle by driving surface and subsurface flow is unclear. Here we present TAM simulations wherein the imposed wetlands reservoirs are replaced by a surface runoff scheme that allows surface liquid to self-consistently redistribute under the influence of topography. To isolate the singular impact of surface runoff on Titan’s climatology, we run simulations without parameterizations of subsurface flow and topography-atmosphere interactions. We discuss the impact of surface runoff on the surface liquid distribution over seasonal timescales and compare the resulting hydrological cycle to observed cloud and surface features, as well as to the hydrological cycles of the TAM wetlands and aquaplanet simulations. While still idealized, this more realistic representation of Titan’s hydrology provides new insight into the complex interaction between Titan’s atmosphere and surface, demonstrates the influence of surface runoff on Titan’s global climate

  10. Gridded Surface Subsurface Hydrologic Analysis (GSSHA) User's Manual; Version 1.43 for Watershed Modeling System 6.1

    National Research Council Canada - National Science Library

    Downer, Charles W; Ogden, Fred L

    2006-01-01

    The need to simulate surface water flows in watersheds with diverse runoff production mechanisms has led to the development of the physically-based hydrologic model Gridded Surface Subsurface Hydrologic Analysis (GSSHA...

  11. Influence of spatial variations of microtopography and infiltration on surface runoff and field scale hydrological connectivity

    NARCIS (Netherlands)

    Appels, W.M.; Bogaart, P.W.; Zee, van der S.E.A.T.M.

    2011-01-01

    Surface runoff on agricultural fields arises when rainfall exceeds infiltration. Excess water ponding in and flowing through local microtopography increases the hydrological connectivity of fields. In turn, an increased level of hydrological connectivity leads to a higher surface runoff flux at the

  12. One-Water Hydrologic Flow Model (MODFLOW-OWHM)

    Science.gov (United States)

    Hanson, Randall T.; Boyce, Scott E.; Schmid, Wolfgang; Hughes, Joseph D.; Mehl, Steffen W.; Leake, Stanley A.; Maddock, Thomas; Niswonger, Richard G.

    2014-01-01

    The One-Water Hydrologic Flow Model (MF-OWHM) is a MODFLOW-based integrated hydrologic flow model (IHM) that is the most complete version, to date, of the MODFLOW family of hydrologic simulators needed for the analysis of a broad range of conjunctive-use issues. Conjunctive use is the combined use of groundwater and surface water. MF-OWHM allows the simulation, analysis, and management of nearly all components of human and natural water movement and use in a physically-based supply-and-demand framework. MF-OWHM is based on the Farm Process for MODFLOW-2005 (MF-FMP2) combined with Local Grid Refinement (LGR) for embedded models to allow use of the Farm Process (FMP) and Streamflow Routing (SFR) within embedded grids. MF-OWHM also includes new features such as the Surface-water Routing Process (SWR), Seawater Intrusion (SWI), and Riparian Evapotrasnpiration (RIP-ET), and new solvers such as Newton-Raphson (NWT) and nonlinear preconditioned conjugate gradient (PCGN). This IHM also includes new connectivities to expand the linkages for deformation-, flow-, and head-dependent flows. Deformation-dependent flows are simulated through the optional linkage to simulated land subsidence with a vertically deforming mesh. Flow-dependent flows now include linkages between the new SWR with SFR and FMP, as well as connectivity with embedded models for SFR and FMP through LGR. Head-dependent flows now include a modified Hydrologic Flow Barrier Package (HFB) that allows optional transient HFB capabilities, and the flow between any two layers that are adjacent along a depositional or erosional boundary or displaced along a fault. MF-OWHM represents a complete operational hydrologic model that fully links the movement and use of groundwater, surface water, and imported water for consumption by irrigated agriculture, but also of water used in urban areas and by natural vegetation. Supply and demand components of water use are analyzed under demand-driven and supply

  13. Modeling post-wildfire hydrological processes with ParFlow

    Science.gov (United States)

    Escobar, I. S.; Lopez, S. R.; Kinoshita, A. M.

    2017-12-01

    Wildfires alter the natural processes within a watershed, such as surface runoff, evapotranspiration rates, and subsurface water storage. Post-fire hydrologic models are typically one-dimensional, empirically-based models or two-dimensional, conceptually-based models with lumped parameter distributions. These models are useful for modeling and predictions at the watershed outlet; however, do not provide detailed, distributed hydrologic processes at the point scale within the watershed. This research uses ParFlow, a three-dimensional, distributed hydrologic model to simulate post-fire hydrologic processes by representing the spatial and temporal variability of soil burn severity (via hydrophobicity) and vegetation recovery. Using this approach, we are able to evaluate the change in post-fire water components (surface flow, lateral flow, baseflow, and evapotranspiration). This work builds upon previous field and remote sensing analysis conducted for the 2003 Old Fire Burn in Devil Canyon, located in southern California (USA). This model is initially developed for a hillslope defined by a 500 m by 1000 m lateral extent. The subsurface reaches 12.4 m and is assigned a variable cell thickness to explicitly consider soil burn severity throughout the stages of recovery and vegetation regrowth. We consider four slope and eight hydrophobic layer configurations. Evapotranspiration is used as a proxy for vegetation regrowth and is represented by the satellite-based Simplified Surface Energy Balance (SSEBOP) product. The pre- and post-fire surface runoff, subsurface storage, and surface storage interactions are evaluated at the point scale. Results will be used as a basis for developing and fine-tuning a watershed-scale model. Long-term simulations will advance our understanding of post-fire hydrological partitioning between water balance components and the spatial variability of watershed processes, providing improved guidance for post-fire watershed management. In reference

  14. Land-surface modelling in hydrological perspective

    DEFF Research Database (Denmark)

    Overgaard, Jesper; Rosbjerg, Dan; Butts, M.B.

    2006-01-01

    The purpose of this paper is to provide a review of the different types of energy-based land-surface models (LSMs) and discuss some of the new possibilities that will arise when energy-based LSMs are combined with distributed hydrological modelling. We choose to focus on energy-based approaches......, and the difficulties inherent in various evaluation procedures are presented. Finally, the dynamic coupling of hydrological and atmospheric models is explored, and the perspectives of such efforts are discussed......., because in comparison to the traditional potential evapotranspiration models, these approaches allow for a stronger link to remote sensing and atmospheric modelling. New opportunities for evaluation of distributed land-surface models through application of remote sensing are discussed in detail...

  15. Quadrotor helicopter for surface hydrological measurements

    Science.gov (United States)

    Pagano, C.; Tauro, F.; Porfiri, M.; Grimaldi, S.

    2013-12-01

    Surface hydrological measurements are typically performed through user-assisted and intrusive field methodologies which can be inadequate to monitor remote and extended areas. In this poster, we present the design and development of a quadrotor helicopter equipped with digital acquisition system and image calibration units for surface flow measurements. This custom-built aerial vehicle is engineered to be lightweight, low-cost, highly customizable, and stable to guarantee optimal image quality. Quadricopter stability guarantees minimal vibrations during image acquisition and, therefore, improved accuracy in flow velocity estimation through large scale particle image velocimetry algorithms or particle tracking procedures. Stability during the vehicle pitching and rolling is achieved by adopting large arm span and high-wing configurations. Further, the vehicle framework is composed of lightweight aluminum and durable carbon fiber for optimal resilience. The open source Ardupilot microcontroller is used for remote control of the quadricopter. The microcontroller includes an inertial measurement unit (IMU) equipped with accelerometers and gyroscopes for stable flight through feedback control. The vehicle is powered by a 3 cell (11.1V) 3000 mAh Lithium-polymer battery. Electronic equipment and wiring are hosted into the hollow arms and on several carbon fiber platforms in the waterproof fuselage. Four 35A high-torque motors are supported at the far end of each arm with 10 × 4.7 inch propellers. Energy dissipation during landing is accomplished by four pivoting legs that, through the use of shock absorbers, prevent the impact energy from affecting the frame thus causing significant damage. The data capturing system consists of a GoPro Hero3 camera and in-house built camera gimbal and shock absorber damping device. The camera gimbal, hosted below the vehicle fuselage, is engineered to maintain the orthogonality of the camera axis with respect to the water surface by

  16. Olkiluoto surface and near-surface hydrological modelling in 2010

    International Nuclear Information System (INIS)

    Karvonen, T.

    2011-08-01

    The modeling approaches carried out with the Olkiluoto surface hydrological model (SHYD) include palaeohydrological evolution of the Olkiluoto Island, examination of the boundary condition at the geosphere-biosphere interface zone, simulations related to infiltration experiment, prediction of the influence of ONKALO on hydraulic head in shallow and deep bedrock and optimisation of the shallow monitoring network. A so called short-term prediction system was developed for continuous updating of the estimated drawdowns caused by ONKALO. The palaeohydrological simulations were computed for a period starting from the time when the highest hills on Olkiluoto Island rose above sea level around 2 500 years ago. The input data needed in the model were produced by the UNTAMO-toolbox. The groundwater flow evolution is primarily driven by the postglacial land uplift and the uncertainty in the land uplift model is the biggest single factor that influences the accuracy of the results. The consistency of the boundary condition at the geosphere-biosphere interface zone (GBIZ) was studied during 2010. The comparison carried out during 2010 showed that pressure head profiles computed with the SHYD model and deep groundwater flow model FEFTRA are in good agreement with each other in the uppermost 100 m of the bedrock. This implies that flux profiles computed with the two approaches are close to each other and hydraulic heads computed at level z=0 m with the SHYD can be used as head boundary condition in the deep groundwater flow model FEFTRA. The surface hydrological model was used to analyse the results of the infiltration experiment. Increase in bedrock recharge inside WCA explains around 60-63 % from the amount of water pumped from OL-KR14 and 37-40 % of the water pumped from OL-KR14 flows towards pumping section via the hydrogeological zones. Pumping from OL-KR14 has only a minor effect on heads and fluxes in zones HZ19A and HZ19C compared to responses caused by leakages into

  17. Surface hydrologic investigations of the Columbia Plateau Region, Washington

    International Nuclear Information System (INIS)

    Leonhart, L.S.

    1979-07-01

    The Washington State portion of the Columbia Plateau is divided into six hydrologic sub-basins on the basis of the principal surface drainage systems present, structural and topographic relationships, and political and other considerations. Baseline descriptions of the surface water systems and resources are presented for the Columbia Plateau with emphasis on the Pasco Sub-basin. A preliminary evaluation of the hydrologic budget for each sub-basin is derived. For each sub-basin, recharge/discharge relationships arising from precipitation/evapotranspiration/runoff, stream losses and gains, and artificial mechanisms are determined on the basis of available data. The net exchange between surface and groundwater systems is evaluated and relative estimates of the net groundwater flow into or out of the sub-basin are obtained. An evaluation is made of hydrologic risk factors arising from: (1) tributary flooding in eastern Washington; and, (2) major flooding of the Columbia River within the Pasco Sub-basin. Scenarios are presented for credible natural and man-generated catastrophic events

  18. Surface hydrologic investigations of the Columbia Plateau region, Washington

    International Nuclear Information System (INIS)

    Leonhart, L.S.

    1979-01-01

    The Washington State portion of the Columbia Plateau is divided into six hydrologic sub-basins on the basis of the principal surface drainage systems present, structural and topographic relationships, and political and other considerations. Baseline descriptions of the surface water systems and resources are presented for the Columbia Plateau with emphasis on the Pasco Sub-basin. A preliminary evaluation of the hydrologic budget for each sub-basin is derived. For each sub-basin, recharge/discharge relationships arising from precipitation/evapotranspiration/runoff, stream losses and gains, and artificial mechanisms are determined on the basis of available data. The net exchange between surface and ground-water systems is evaluated and relative estimates of the net ground-water flow into or out of the sub-basin are obtained. An evaluation is made of hydrologic risk factors arising from: (1) tributary flooding in eastern Washington; and (2) major flooding of the Columbia River within the Pasco Sub-basin. Scenarios are presented for credible natural and man-generated catastrophic events

  19. Hydrology

    Science.gov (United States)

    Sharp, John M.

    1977-01-01

    Lists many recent research projects in hydrology, including flow in fractured media, improvements in remote-sensing techniques, effects of urbanization on water resources, and developments in drainage basins. (MLH)

  20. Macroscale hydrologic modeling of ecologically relevant flow metrics

    Science.gov (United States)

    Wenger, Seth J.; Luce, Charles H.; Hamlet, Alan F.; Isaak, Daniel J.; Neville, Helen M.

    2010-09-01

    Stream hydrology strongly affects the structure of aquatic communities. Changes to air temperature and precipitation driven by increased greenhouse gas concentrations are shifting timing and volume of streamflows potentially affecting these communities. The variable infiltration capacity (VIC) macroscale hydrologic model has been employed at regional scales to describe and forecast hydrologic changes but has been calibrated and applied mainly to large rivers. An important question is how well VIC runoff simulations serve to answer questions about hydrologic changes in smaller streams, which are important habitat for many fish species. To answer this question, we aggregated gridded VIC outputs within the drainage basins of 55 streamflow gages in the Pacific Northwest United States and compared modeled hydrographs and summary metrics to observations. For most streams, several ecologically relevant aspects of the hydrologic regime were accurately modeled, including center of flow timing, mean annual and summer flows and frequency of winter floods. Frequencies of high and low flows in the summer were not well predicted, however. Predictions were worse for sites with strong groundwater influence, and some sites showed errors that may result from limitations in the forcing climate data. Higher resolution (1/16th degree) modeling provided small improvements over lower resolution (1/8th degree). Despite some limitations, the VIC model appears capable of representing several ecologically relevant hydrologic characteristics in streams, making it a useful tool for understanding the effects of hydrology in delimiting species distributions and predicting the potential effects of climate shifts on aquatic organisms.

  1. Assessment and Enhancement of MERRA Land Surface Hydrology Estimates

    Science.gov (United States)

    Reichle, Rolf H.; Koster, Randal D.; deLannoy, Gabrielle J. M.; Forman, Barton A.; Liu, Qing; Mahanama, Sarith P. P.; Toure, Ally

    2012-01-01

    The Modern-Era Retrospective analysis for Research and Applications (MERRA) is a state-ofthe-art reanalysis that provides, in addition to atmospheric fields, global estimates of soil moisture, latent heat flux, snow, and runoff for 1979-present. This study introduces a supplemental and improved set of land surface hydrological fields ("MERRA-Land") generated by re-running a revised version of the land component of the MERRA system. Specifically, the MERRA-Land estimates benefit from corrections to the precipitation forcing with the Global Precipitation Climatology Project pentad product (version 2.1) and from revised parameter values in the rainfall interception model, changes that effectively correct for known limitations in the MERRA surface meteorological forcings. The skill (defined as the correlation coefficient of the anomaly time series) in land surface hydrological fields from MERRA and MERRA-Land is assessed here against observations and compared to the skill of the state-of-the-art ERA-Interim (ERA-I) reanalysis. MERRA-Land and ERA-I root zone soil moisture skills (against in situ observations at 85 US stations) are comparable and significantly greater than that of MERRA. Throughout the northern hemisphere, MERRA and MERRA-Land agree reasonably well with in situ snow depth measurements (from 583 stations) and with snow water equivalent from an independent analysis. Runoff skill (against naturalized stream flow observations from 18 US basins) of MERRA and MERRA-Land is typically higher than that of ERA-I. With a few exceptions, the MERRA-Land data appear more accurate than the original MERRA estimates and are thus recommended for those interested in using MERRA output for land surface hydrological studies.

  2. A spatial assessment of stream-flow characteristics and hydrologic ...

    African Journals Online (AJOL)

    The global hydrologic regime has been intensively altered through activities such as dam construction, water abstraction, and inter-basin transfers. This paper uses the Range of Variability Approach (RVA) and daily stream flow records from nine gauging stations to characterize stream-flow post dam construction in the ...

  3. Surface hydrology of drainage basins disturbed by surface mining and reclamation, central Pennsylvania

    International Nuclear Information System (INIS)

    Ritter, J.B.

    1990-01-01

    Infilration capacity of newly reclaimed minesoils is uniformly low (< 1 cm/hr) and generally increases (up to 6 cm/hr) with age, the magnitude of increase being dependent on soil characteristics and vegetation. In drainage basins with lower rates of infiltration recovery (< 2 cm/hr), infiltration-excess overland flow is the dominant runoff process. Increased peek runoff rate and stream power in the basins are sufficient to initiate drainage network evolution, with phases of network expansion and abstraction. In contrast, in basins where infiltration recovery is greater than 2 cm/hr, the hydrologic system is initially dominated by infiltration-excess overland flow but evolves toward a system dominated by saturation overland flow. Drainage development is limited to skeletal network initiation and elongation and occurs during the early period of infiltration-excess dominated flow conditions. Total runoff remains essentially constant due to increased proportions of return flow, reflected in the extended and less steep recession limb of saturation-dominated storm hydrographs. The results of this study are applicable to hydrologic prediction for purposes of surface mine permitting and reclamation design. Previously limited availability of rainfall-runoff data from watersheds disturbed by surface mining preclude adequate calibration of empirical methods, such as the runoff curve number method, or evaluation of a more sophisticated approach, such as the use of distributed hydrologic models, for hydrologic prediction. Runoff curve numbers calibrated by means of rainfall-runoff data from the study drainage basins indicate that presently accepted methods of determining curve numbers, using pre-mine soil classification, underestimate total runoff by as much as 50%

  4. The Influence of Runoff and Surface Hydrology on Titan's Weather and Climate

    Science.gov (United States)

    Faulk, S.; Lora, J. M.; Mitchell, J.; Moon, S.

    2017-12-01

    Titan's surface liquid distribution has been shown by general circulation models (GCMs) to greatly influence the hydrological cycle, producing characteristic weather and seasonal climate patterns. Simulations from the Titan Atmospheric Model (TAM) with imposed polar methane "wetlands" reservoirs realistically produce observed cloud features and temperature profiles of Titan's atmosphere, whereas "aquaplanet" simulations with a global methane ocean are not as successful. In addition, wetlands simulations, unlike aquaplanet simulations, demonstrate strong correlations between extreme rainfall behavior and observed geomorphic features, indicating the influential role of precipitation in shaping Titan's surface. The wetlands configuration is, in part, motivated by Titan's large-scale topography featuring low-latitude highlands and high-latitude lowlands, with the implication being that methane may concentrate in the high-latitude lowlands by way of runoff and subsurface flow of a global or regional methane table. However, the extent to which topography controls the surface liquid distribution and thus impacts the global hydrological cycle by driving surface and subsurface flow is unclear. Here we present TAM simulations wherein the imposed wetlands reservoirs are replaced by a surface runoff scheme that allows surface liquid to self-consistently redistribute under the influence of topography. We discuss the impact of surface runoff on the surface liquid distribution over seasonal timescales and compare the resulting hydrological cycle to observed cloud and surface features, as well as to the hydrological cycles of the TAM wetlands and aquaplanet simulations. While still idealized, this more realistic representation of Titan's hydrology provides new insight into the complex interaction between Titan's atmosphere and surface, demonstrates the influence of surface runoff on Titan's global climate, and lays the groundwork for further surface hydrology developments in Titan

  5. Effect of water table dynamics on land surface hydrologic memory

    Science.gov (United States)

    Lo, Min-Hui; Famiglietti, James S.

    2010-11-01

    The representation of groundwater dynamics in land surface models has received considerable attention in recent years. Most studies have found that soil moisture increases after adding a groundwater component because of the additional supply of water to the root zone. However, the effect of groundwater on land surface hydrologic memory (persistence) has not been explored thoroughly. In this study we investigate the effect of water table dynamics on National Center for Atmospheric Research Community Land Model hydrologic simulations in terms of land surface hydrologic memory. Unlike soil water or evapotranspiration, results show that land surface hydrologic memory does not always increase after adding a groundwater component. In regions where the water table level is intermediate, land surface hydrologic memory can even decrease, which occurs when soil moisture and capillary rise from groundwater are not in phase with each other. Further, we explore the hypothesis that in addition to atmospheric forcing, groundwater variations may also play an important role in affecting land surface hydrologic memory. Analyses show that feedbacks of groundwater on land surface hydrologic memory can be positive, negative, or neutral, depending on water table dynamics. In regions where the water table is shallow, the damping process of soil moisture variations by groundwater is not significant, and soil moisture variations are mostly controlled by random noise from atmospheric forcing. In contrast, in regions where the water table is very deep, capillary fluxes from groundwater are small, having limited potential to affect soil moisture variations. Therefore, a positive feedback of groundwater to land surface hydrologic memory is observed in a transition zone between deep and shallow water tables, where capillary fluxes act as a buffer by reducing high-frequency soil moisture variations resulting in longer land surface hydrologic memory.

  6. Chapter 1: Hydrologic exchange flows and their ecological consequences in river corridors

    Science.gov (United States)

    Harvey, Judson

    2016-01-01

    The actively flowing waters of streams and rivers remain in close contact with surrounding off-channel and subsurface environments. These hydrologic linkages between relatively fast flowing channel waters, with more slowly flowing waters off-channel and in the subsurface, are collectively referred to as hydrologic exchange flows (HEFs). HEFs include surface exchange with a channel’s marginal areas and subsurface flow through the streambed (hyporheic flow), as well as storm-driven bank storage and overbank flows onto floodplains. HEFs are important, not only for storing water and attenuating flood peaks, but also for their role in influencing water conservation, water quality improvement, and related outcomes for ecological values and services of aquatic ecosystems. Biogeochemical opportunities for chemical transformations are increased by HEFs as a result of the prolonged contact between flowing waters and geochemically and microbially active surfaces of sediments and vegetation. Chemical processing is intensified and water quality is often improved by removal of excess nutrients, metals, and organic contaminants from flowing waters. HEFs also are important regulators of organic matter decomposition, nutrient recycling, and stream metabolism that helps establish a balanced and resilient aquatic food web. The shallow and protected storage zones associated with HEFs support nursery and feeding areas for aquatic organisms that sustain aquatic biological diversity. Understanding of these varied roles for HEFs has been driven by the related disciplines of stream ecology, fluvial geomorphology, surface-water hydraulics, and groundwater hydrology. A current research emphasis is on the role that HEFs play in altered flow regimes, including restoration to achieve diverse goals, such as expanding aquatic habitats and managing dissolved and suspended river loads to reduce over-fertilization of coastal waters and offset wetland loss. New integrative concepts and models are

  7. Description of climate, surface hydrology, and near-surface hydrogeology. Simpevarp 1.2

    International Nuclear Information System (INIS)

    Werner, Kent; Bosson, Emma; Berglund, Sten

    2005-04-01

    This report presents and evaluates the site investigations and primary data on meteorology, surface hydrology and near-surface hydrogeology that are available in the Simpevarp 1.2 'data freeze'. The main objective is to update the previous Simpevarp 1.1 description of the meteorological, surface hydrological and near-surface hydrogeological conditions in the Simpevarp area. Based on the Simpevarp 1.2 dataset, an updated conceptual and descriptive model of the surface and near-surface water flow conditions in the Simpevarp area is presented. In cases where site investigation data are not yet available, regional and/or generic data are used as input to the modelling. GIS- and process-based tools, used for initial quantitative flow modelling, are also presented. The objectives of this initial quantitative modelling are to illustrate, quantify and support the site descriptive model, and also to produce relevant input data to the ecological systems modelling within the SKB SurfaceNet framework.For the Simpevarp 1.2 model, the relevant site investigations include the establishment of one local meteorological station and surface-hydrological stations for discharge measurements, delineation and description of catchment areas, manual discharge measurements in water courses, slug tests in groundwater monitoring wells, and manual groundwater level measurements. In addition, other investigations have also contributed to the modelling, providing data on geometry (including topography), data from surface-based geological investigations and boreholes in Quaternary deposits, and data on the hydrogeological properties of the bedrock. The conceptual and descriptive modelling includes an identification and basic description of type areas, domains and interfaces between domains within the model area. The surface and near-surface flow system is described, including the assignment of hydrogeological properties to HSDs (Hydraulic Soil Domains) of Quaternary deposits based on a

  8. Description of climate, surface hydrology, and near-surface hydrogeology. Simpevarp 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Kent [SWECO VIAK AB/Golder Associates AB, Stockholm (Sweden); Bosson, Emma; Berglund, Sten [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

    2005-04-01

    This report presents and evaluates the site investigations and primary data on meteorology, surface hydrology and near-surface hydrogeology that are available in the Simpevarp 1.2 'data freeze'. The main objective is to update the previous Simpevarp 1.1 description of the meteorological, surface hydrological and near-surface hydrogeological conditions in the Simpevarp area. Based on the Simpevarp 1.2 dataset, an updated conceptual and descriptive model of the surface and near-surface water flow conditions in the Simpevarp area is presented. In cases where site investigation data are not yet available, regional and/or generic data are used as input to the modelling. GIS- and process-based tools, used for initial quantitative flow modelling, are also presented. The objectives of this initial quantitative modelling are to illustrate, quantify and support the site descriptive model, and also to produce relevant input data to the ecological systems modelling within the SKB SurfaceNet framework.For the Simpevarp 1.2 model, the relevant site investigations include the establishment of one local meteorological station and surface-hydrological stations for discharge measurements, delineation and description of catchment areas, manual discharge measurements in water courses, slug tests in groundwater monitoring wells, and manual groundwater level measurements. In addition, other investigations have also contributed to the modelling, providing data on geometry (including topography), data from surface-based geological investigations and boreholes in Quaternary deposits, and data on the hydrogeological properties of the bedrock. The conceptual and descriptive modelling includes an identification and basic description of type areas, domains and interfaces between domains within the model area. The surface and near-surface flow system is described, including the assignment of hydrogeological properties to HSDs (Hydraulic Soil Domains) of Quaternary deposits based on a

  9. Integrating remotely sensed surface water extent into continental scale hydrology.

    Science.gov (United States)

    Revilla-Romero, Beatriz; Wanders, Niko; Burek, Peter; Salamon, Peter; de Roo, Ad

    2016-12-01

    In hydrological forecasting, data assimilation techniques are employed to improve estimates of initial conditions to update incorrect model states with observational data. However, the limited availability of continuous and up-to-date ground streamflow data is one of the main constraints for large-scale flood forecasting models. This is the first study that assess the impact of assimilating daily remotely sensed surface water extent at a 0.1° × 0.1° spatial resolution derived from the Global Flood Detection System (GFDS) into a global rainfall-runoff including large ungauged areas at the continental spatial scale in Africa and South America. Surface water extent is observed using a range of passive microwave remote sensors. The methodology uses the brightness temperature as water bodies have a lower emissivity. In a time series, the satellite signal is expected to vary with changes in water surface, and anomalies can be correlated with flood events. The Ensemble Kalman Filter (EnKF) is a Monte-Carlo implementation of data assimilation and used here by applying random sampling perturbations to the precipitation inputs to account for uncertainty obtaining ensemble streamflow simulations from the LISFLOOD model. Results of the updated streamflow simulation are compared to baseline simulations, without assimilation of the satellite-derived surface water extent. Validation is done in over 100 in situ river gauges using daily streamflow observations in the African and South American continent over a one year period. Some of the more commonly used metrics in hydrology were calculated: KGE', NSE, PBIAS%, R 2 , RMSE, and VE. Results show that, for example, NSE score improved on 61 out of 101 stations obtaining significant improvements in both the timing and volume of the flow peaks. Whereas the validation at gauges located in lowland jungle obtained poorest performance mainly due to the closed forest influence on the satellite signal retrieval. The conclusion is that

  10. Soil macropores: Control on infiltration, hillslope and surface hydrology on a reclaimed surface-mined watershed

    International Nuclear Information System (INIS)

    Guebert, M.D.; Gardner, T.W.

    1992-01-01

    The hydrologic response of a surface-mined watershed in central Pennsylvania is controlled by rapid macropore flow within the unsaturated man-made topsoil. Newly reclaimed surface-mined watersheds in central Pennsylvania exhibit low steady-state infiltration rates (1--2 cm/hr) and produce runoff dominated by infiltration-excess overland flow. However, within four years after reclamation, infiltration rates on some mine surfaces approach premined rates (8 cm/hr). As infiltration rate increases, the volume of infiltrated water increases, but the total porosity of minesoil matrix remains constant. There is little change in the surface discharge volume, indicating that infiltrated water continues to contribute to the basin surface discharge by the processes of throughflow and return flow. Throughflow in the topsoil horizon occurs in rapid response to rainfall input, producing large volumes of water with throughflow rates closely related to rainfall rates and with throughflow peaks following rainfall peaks by only minutes. Increased return flow alters the shape of the surface runoff hydrograph by slightly lagging behind infiltration excess overland flow. These changes in the shape of the surface runoff hydrograph reduce the potential for severe gully erosion on the reclaimed site. In addition, throughflow water remains predominantly in the topsoil horizon, and therefore has limited contact with potentially acid-producing backfill. Better understanding of macropore flow processes in reclaimed minesoils will help investigators evaluate past strategies and develop new reclamation techniques that will minimize the short-term surface erosional effects of mining and reclamation, while optimizing the long-term effluent and groundwater quality

  11. Classifying low flow hydrological regimes at a regional scale

    Science.gov (United States)

    Kirkby, M. J.; Gallart, F.; Kjeldsen, T. R.; Irvine, B. J.; Froebrich, J.; Lo Porto, A.; de Girolamo, A.; Mirage Team

    2011-12-01

    The paper uses a simple water balance model that partitions the precipitation between actual evapotranspiration, quick flow and delayed flow, and has sufficient complexity to capture the essence of climate and vegetation controls on this partitioning. Using this model, monthly flow duration curves have been constructed from climate data across Europe to address the relative frequency of ecologically critical low flow stages in semi-arid rivers, when flow commonly persists only in disconnected pools in the river bed. The hydrological model is based on a dynamic partitioning of precipitation to estimate water available for evapotranspiration and plant growth and for residual runoff. The duration curve for monthly flows has then been analysed to give an estimate of bankfull flow based on recurrence interval. Arguing from observed ratios of cross-sectional areas at flood and low flows, hydraulic geometry suggests that disconnected flow under "pool" conditions is approximately 0.1% of bankfull flow. Flow duration curves define a measure of bankfull discharge on the basis of frequency. The corresponding frequency for pools is then read from the duration curve, using this (0.1%) ratio to estimate pool discharge from bank full discharge. The flow duration curve then provides an estimate of the frequency of poorly connected pool conditions, corresponding to this discharge, that constrain survival of river-dwelling arthropods and fish. The methodology has here been applied across Europe at 15 km resolution, and the potential is demonstrated for applying the methodology under alternative climatic scenarios.

  12. Classifying low flow hydrological regimes at a regional scale

    Directory of Open Access Journals (Sweden)

    M. J. Kirkby

    2011-12-01

    Full Text Available The paper uses a simple water balance model that partitions the precipitation between actual evapotranspiration, quick flow and delayed flow, and has sufficient complexity to capture the essence of climate and vegetation controls on this partitioning. Using this model, monthly flow duration curves have been constructed from climate data across Europe to address the relative frequency of ecologically critical low flow stages in semi-arid rivers, when flow commonly persists only in disconnected pools in the river bed. The hydrological model is based on a dynamic partitioning of precipitation to estimate water available for evapotranspiration and plant growth and for residual runoff. The duration curve for monthly flows has then been analysed to give an estimate of bankfull flow based on recurrence interval. Arguing from observed ratios of cross-sectional areas at flood and low flows, hydraulic geometry suggests that disconnected flow under "pool" conditions is approximately 0.1% of bankfull flow. Flow duration curves define a measure of bankfull discharge on the basis of frequency. The corresponding frequency for pools is then read from the duration curve, using this (0.1% ratio to estimate pool discharge from bank full discharge. The flow duration curve then provides an estimate of the frequency of poorly connected pool conditions, corresponding to this discharge, that constrain survival of river-dwelling arthropods and fish. The methodology has here been applied across Europe at 15 km resolution, and the potential is demonstrated for applying the methodology under alternative climatic scenarios.

  13. Evaluating post-wildfire hydrologic recovery using ParFlow in southern California

    Science.gov (United States)

    Lopez, S. R.; Kinoshita, A. M.; Atchley, A. L.

    2016-12-01

    Wildfires are naturally occurring hazards that can have catastrophic impacts. They can alter the natural processes within a watershed, such as surface runoff and subsurface water storage. Generally, post-fire hydrologic models are either one-dimensional, empirically-based models, or two-dimensional, conceptually-based models with lumped parameter distributions. These models are useful in providing runoff measurements at the watershed outlet; however, do not provide distributed hydrologic simulation at each point within the watershed. This research demonstrates how ParFlow, a three-dimensional, distributed hydrologic model can simulate post-fire hydrologic processes by representing soil burn severity (via hydrophobicity) and vegetation recovery as they vary both spatially and temporally. Using this approach, we are able to evaluate the change in post-fire water components (surface flow, lateral flow, baseflow, and evapotranspiration). This model is initially developed for a hillslope in Devil Canyon, burned in 2003 by the Old Fire in southern California (USA). The domain uses a 2m-cell size resolution over a 25 m by 25 m lateral extent. The subsurface reaches 2 m and is assigned a variable cell thickness, allowing an explicit consideration of the soil burn severity throughout the stages of recovery and vegetation regrowth. Vegetation regrowth is incorporated represented by satellite-based Enhanced Vegetation Index (EVI) products. The pre- and post-fire surface runoff, subsurface storage, and surface storage interactions are evaluated and will be used as a basis for developing a watershed-scale model. Long-term continuous simulations will advance our understanding of post-fire hydrological partitioning between water balance components and the spatial variability of watershed processes, providing improved guidance for post-fire watershed management.

  14. Unsteady Flows Control Hydrologic Turnover Rates in Antarctic Hyporheic Zones

    Science.gov (United States)

    Wlostowski, A. N.; Gooseff, M. N.; McKnight, D. M.; Lyons, W. B.; Saelens, E.

    2016-12-01

    Hydrologic turnover of the hyporheic zone (HZ) is the process of HZ flowpaths receiving water and solutes from the stream channel while simultaneously contributing water and solutes from the HZ back to the stream channel. The influence of hydrologic turnover on HZ solute storage depends on the relative magnitude of hyporheic exchange rates (i.e. physical transport) and biogeochemical reaction rates. Because both exchange rates and reaction rates are unsteady in natural systems, the availability of solutes in the HZ is controlled by the legacy of hydraulic and biological conditions. In this study, we quantify the influence of unsteady flows on hydrologic turnover of the HZ. We study a glacial melt stream in the McMurdo Dry Valleys of Antarctica (MDVs). The MDVs provide an ideal setting for investigating hydrologic and chemical storage characteristics of HZs, because nearly all streamflow is generated from glacier melt and the HZ is vertically bounded by continuous permafrost. A dense network of shallow groundwater wells and piezometers was installed along a 60-meter reach of Von Guerard Stream. 12 days of continuous water level data in each well was used to compute the magnitude and direction of 2D hydraulic gradients between the stream channel and lateral hyporheic aquifer. Piezometers were sampled daily for stable isotope abundances. The direction and magnitude of the cross-valley (CV), perpendicular to the thalweg, component of hydraulic gradients is sensitive to daily flood events and exhibits significant spatial heterogeneity. CV gradients are consistently oriented from the hyporheic aquifer towards the stream channel on 2 sections of the study reach, whereas CV gradients are consistently oriented from the stream channel towards the hyporheic aquifer on 1 section. Three sections show diel changes in orientation of CV gradients, coincident with the passage of daily flood events. During a 4-day period of low flows, the HZ is isotopically distinct from the stream

  15. Improving Long-term Post-wildfire hydrologic simulations using ParFlow

    Science.gov (United States)

    Lopez, S. R.; Kinoshita, A. M.

    2015-12-01

    Wildfires alter the natural hydrologic processes within a watershed. After vegetation is burned, the combustion of organic material and debris settles into the soil creating a hydrophobic layer beneath the soil surface with varying degree of thickness and depth. Vegetation regrowth rates vary as a function of radiative exposure, burn severity, and precipitation patterns. Hydrologic models used by the Burned Area Emergency Response (BAER) teams use input data and model calibration constraints that are generally either one-dimensional, empirically-based models, or two-dimensional, conceptually-based models with lumped parameter distributions. These models estimate runoff measurements at the watershed outlet; however, do not provide a distributed hydrologic simulation at each point within the watershed. This work uses ParFlow, a three-dimensional, distributed hydrologic model to (1) correlate burn severity with hydrophobicity, (2) evaluate vegetation recovery rate on water components, and (3) improve flood prediction for managers to help with resource allocation and management operations in burned watersheds. ParFlow is applied to Devil Canyon (43 km2) in San Bernardino, California, which was 97% burned in the 2003 Old Fire. The model set-up uses a 30m-cell size resolution over a 6.7 km by 6.4 km lateral extent. The subsurface reaches 30 m and is assigned a variable cell thickness. Variable subsurface thickness allows users to explicitly consider the degree of recovery throughout the stages of regrowth. Burn severity maps from remotely sensed imagery are used to assign initial hydrophobic layer parameters and thickness. Vegetation regrowth is represented with satellite an Enhanced Vegetation Index. Pre and post-fire hydrologic response is evaluated using runoff measurements at the watershed outlet, and using water component (overland flow, lateral flow, baseflow) measurements.

  16. Hydrologic flow path development varies by aspect during spring snowmelt in complex subalpine terrain

    Science.gov (United States)

    Webb, Ryan W.; Fassnacht, Steven R.; Gooseff, Michael N.

    2018-01-01

    In many mountainous regions around the world, snow and soil moisture are key components of the hydrologic cycle. Preferential flow paths of snowmelt water through snow have been known to occur for years with few studies observing the effect on soil moisture. In this study, statistical analysis of the topographical and hydrological controls on the spatiotemporal variability of snow water equivalent (SWE) and soil moisture during snowmelt was undertaken at a subalpine forested setting with north, south, and flat aspects as a seasonally persistent snowpack melts. We investigated if evidence of preferential flow paths in snow can be observed and the effect on soil moisture through measurements of snow water equivalent and near-surface soil moisture, observing how SWE and near-surface soil moisture vary on hillslopes relative to the toes of hillslopes and flat areas. We then compared snowmelt infiltration beyond the near-surface soil between flat and sloping terrain during the entire snowmelt season using soil moisture sensor profiles. This study was conducted during varying snowmelt seasons representing above-normal, relatively normal, and below-normal snow seasons in northern Colorado. Evidence is presented of preferential meltwater flow paths at the snow-soil interface on the north-facing slope causing increases in SWE downslope and less infiltration into the soil at 20 cm depth; less association is observed in the near-surface soil moisture (top 7 cm). We present a conceptualization of the meltwater flow paths that develop based on slope aspect and soil properties. The resulting flow paths are shown to divert at least 4 % of snowmelt laterally, accumulating along the length of the slope, to increase the snow water equivalent by as much as 170 % at the base of a north-facing hillslope. Results from this study show that snow acts as an extension of the vadose zone during spring snowmelt and future hydrologic investigations will benefit from studying the snow and soil

  17. Integrated Surface/subsurface flow modeling in PFLOTRAN

    Energy Technology Data Exchange (ETDEWEB)

    Painter, Scott L [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-01

    Understanding soil water, groundwater, and shallow surface water dynamics as an integrated hydrological system is critical for understanding the Earth’s critical zone, the thin outer layer at our planet’s surface where vegetation, soil, rock, and gases interact to regulate the environment. Computational tools that take this view of soil moisture and shallow surface flows as a single integrated system are typically referred to as integrated surface/subsurface hydrology models. We extend the open-source, highly parallel, subsurface flow and reactive transport simulator PFLOTRAN to accommodate surface flows. In contrast to most previous implementations, we do not represent a distinct surface system. Instead, the vertical gradient in hydraulic head at the land surface is neglected, which allows the surface flow system to be eliminated and incorporated directly into the subsurface system. This tight coupling approach leads to a robust capability and also greatly simplifies implementation in existing subsurface simulators such as PFLOTRAN. Successful comparisons to independent numerical solutions build confidence in the approximation and implementation. Example simulations of the Walker Branch and East Fork Poplar Creek watersheds near Oak Ridge, Tennessee demonstrate the robustness of the approach in geometrically complex applications. The lack of a robust integrated surface/subsurface hydrology capability had been a barrier to PFLOTRAN’s use in critical zone studies. This work addresses that capability gap, thus enabling PFLOTRAN as a community platform for building integrated models of the critical zone.

  18. Surface obstacles in pulsatile flow

    Science.gov (United States)

    Carr, Ian A.; Plesniak, Michael W.

    2017-11-01

    Flows past obstacles mounted on flat surfaces have been widely studied due to their ubiquity in nature and engineering. For nearly all of these studies, the freestream flow over the obstacle was steady, i.e., constant velocity, unidirectional flow. Unsteady, pulsatile flows occur frequently in biology, geophysics, biomedical engineering, etc. Our study is aimed at extending the comprehensive knowledge base that exists for steady flows to considerably more complex pulsatile flows. Characterizing the vortex and wake dynamics of flows around surface obstacles embedded in pulsatile flows can provide insights into the underlying physics in all wake and junction flows. In this study, we experimentally investigate the wake of two canonical obstacles: a cube and a circular cylinder with an aspect ratio of unity. Our previous studies of a surface-mounted hemisphere in pulsatile flow are used as a baseline for these two new, more complex geometries. Phase-averaged PIV and hot-wire anemometry are used to characterize the dynamics of coherent structures in the wake and at the windward junction of the obstacles. Complex physics occur during the deceleration phase of the pulsatile inflow. We propose a framework for understanding these physics based on self-induced vortex propagation, similar to the phenomena exhibited by vortex rings.

  19. Flow over riblet curved surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, J B R; Freire, A P Silva, E-mail: atila@mecanica.ufrj.br [Mechanical Engineering Program, Federal University of Rio de Janeiro (COPPE/UFRJ), C.P. 68503, 21.941-972, Rio de Janeiro, RJ (Brazil)

    2011-12-22

    The present work studies the mechanics of turbulent drag reduction over curved surfaces by riblets. The effects of surface modification on flow separation over steep and smooth curved surfaces are investigated. Four types of two-dimensional surfaces are studied based on the morphometric parameters that describe the body of a blue whale. Local measurements of mean velocity and turbulence profiles are obtained through laser Doppler anemometry (LDA) and particle image velocimetry (PIV).

  20. Land-surface modelling in hydrological perspective ? a review

    OpenAIRE

    Overgaard , J.; Rosbjerg , D.; Butts , M. B.

    2006-01-01

    International audience; The purpose of this paper is to provide a review of the different types of energy-based land-surface models (LSMs) and discuss some of the new possibilities that will arise when energy-based LSMs are combined with distributed hydrological modelling. We choose to focus on energy-based approaches, because in comparison to the traditional potential evapotranspiration models, these approaches allow for a stronger link to remote sensing and atmospheric modelling. New opport...

  1. SOUTH-WESTERN APUSENI MOUNTAINS SMALL RIVERS SEASONAL HYDROLOGICAL FLOW REGIME

    Directory of Open Access Journals (Sweden)

    SOROCOVSCHI V.

    2015-03-01

    Full Text Available The researched area overlaps the territory belonging to Crişul Alb and Crişul Negru river basins. The study is based on processing and interpretation data from 33 hydrometric stations of which 18 stations control hydrographic basins with surfaces of less than 150 km2. To highlight the seasonal hydrological flow regime, we took into account three time periods (1950-1967, 1950-2009 and 1970-2009. For all rivers the highest flow values appear during springtime, while the smallest contribution to the multiannual average volume is realized in autumn. The time variation of seasonal flow was highlighted by analysis and variation of extreme values coefficients and also by analysing seasonal flow trends that appeared in all three time periods.

  2. Challenges for understanding Antarctic surface hydrology and ice-shelf stability

    Science.gov (United States)

    Kingslake, J.; Bell, R. E.; Banwell, A. F.; Boghosian, A.; Spergel, J.; Trusel, L. D.

    2017-12-01

    It is widely hypothesized that surface meltwater can contribute to ice mass loss in Antarctica through its impact on ice-shelf stability. Meltwater potentially expedites ice-shelf calving by flowing into and enlarging existing crevasses, and could even trigger ice-shelf disintegration via stresses generated by melt ponds. When ice shelves collapse, the adjacent grounded ice accelerates and thins, which contributes to sea-level rise. How these mechanisms mediate the interactions between the atmosphere, the ocean and the ice sheet is the subject of long-standing research efforts. The drainage of water across the surface of the Antarctic Ice Sheet and its ice shelves is beginning to be recognized as another important aspect of the system. Recent studies have revealed that surface meltwater drainage is more widespread than previously thought and that surface hydrological systems in Antarctica may expand and proliferate this century. Contrasting hypotheses regarding the impact of the proliferation of drainage systems on ice-shelf stability have emerged. Surface drainage could deliver meltwater to vulnerable area or export meltwater from ice shelves entirely. Which behavior dominates may have a large impact on the future response of the Antarctic Ice Sheet to atmospheric warming. We will discuss these recent discoveries and hypotheses, as well as new detailed studies of specific areas where hydrological systems are well developed, such as Amery and Nimrod Ice Shelves. We will highlight analogies that can be drawn with Greenlandic (near-)surface hydrology and, crucially, where hydrological systems on the two ice sheets are very different, leading to potentially important gaps in our understanding. Finally, we will look ahead to the key questions that we argue will need to be if we are to determine the role Antarctic surface hydrology could play in the future of the ice sheet. These include: Where does meltwater pond today and how will this change this century? What

  3. Towards an Improved Represenation of Reservoirs and Water Management in a Land Surface-Hydrology Model

    Science.gov (United States)

    Yassin, F.; Anis, M. R.; Razavi, S.; Wheater, H. S.

    2017-12-01

    Water management through reservoirs, diversions, and irrigation have significantly changed river flow regimes and basin-wide energy and water balance cycles. Failure to represent these effects limits the performance of land surface-hydrology models not only for streamflow prediction but also for the estimation of soil moisture, evapotranspiration, and feedbacks to the atmosphere. Despite recent research to improve the representation of water management in land surface models, there remains a need to develop improved modeling approaches that work in complex and highly regulated basins such as the 406,000 km2 Saskatchewan River Basin (SaskRB). A particular challenge for regional and global application is a lack of local information on reservoir operational management. To this end, we implemented a reservoir operation, water abstraction, and irrigation algorithm in the MESH land surface-hydrology model and tested it over the SaskRB. MESH is Environment Canada's Land Surface-hydrology modeling system that couples Canadian Land Surface Scheme (CLASS) with hydrological routing model. The implemented reservoir algorithm uses an inflow-outflow relationship that accounts for the physical characteristics of reservoirs (e.g., storage-area-elevation relationships) and includes simplified operational characteristics based on local information (e.g., monthly target volume and release under limited, normal, and flood storage zone). The irrigation algorithm uses the difference between actual and potential evapotranspiration to estimate irrigation water demand. This irrigation demand is supplied from the neighboring reservoirs/diversion in the river system. We calibrated the model enabled with the new reservoir and irrigation modules in a multi-objective optimization setting. Results showed that the reservoir and irrigation modules significantly improved the MESH model performance in generating streamflow and evapotranspiration across the SaskRB and that this our approach provides

  4. Surface flow measurements from drones

    Science.gov (United States)

    Tauro, Flavia; Porfiri, Maurizio; Grimaldi, Salvatore

    2016-09-01

    Drones are transforming the way we sense and interact with the environment. However, despite their increased capabilities, the use of drones in geophysical sciences usually focuses on image acquisition for generating high-resolution maps. Motivated by the increasing demand for innovative and high performance geophysical observational methodologies, we posit the integration of drone technology and optical sensing toward a quantitative characterization of surface flow phenomena. We demonstrate that a recreational drone can be used to yield accurate surface flow maps of sub-meter water bodies. Specifically, drone's vibrations do not hinder surface flow observations, and velocity measurements are in agreement with traditional techniques. This first instance of quantitative water flow sensing from a flying drone paves the way to novel observations of the environment.

  5. A Hydrological Concept including Lateral Water Flow Compatible with the Biogeochemical Model ForSAFE

    Directory of Open Access Journals (Sweden)

    Giuliana Zanchi

    2016-03-01

    Full Text Available The study presents a hydrology concept developed to include lateral water flow in the biogeochemical model ForSAFE. The hydrology concept was evaluated against data collected at Svartberget in the Vindeln Research Forest in Northern Sweden. The results show that the new concept allows simulation of a saturated and an unsaturated zone in the soil as well as water flow that reaches the stream comparable to measurements. The most relevant differences compared to streamflow measurements are that the model simulates a higher base flow in winter and lower flow peaks after snowmelt. These differences are mainly caused by the assumptions made to regulate the percolation at the bottom of the simulated soil columns. The capability for simulating lateral flows and a saturated zone in ForSAFE can greatly improve the simulation of chemical exchange in the soil and export of elements from the soil to watercourses. Such a model can help improve the understanding of how environmental changes in the forest landscape will influence chemical loads to surface waters.

  6. Description of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

    International Nuclear Information System (INIS)

    Johansson, Per-Olof

    2008-12-01

    This report describes the modelling of the surface hydrology and near-surface hydrogeology that was performed for the final site descriptive model of Forsmark produced in the site investigation stage, SDM-Site Forsmark. The comprehensive investigation and monitoring programme forms a strong basis for the developed conceptual and descriptive model of the hydrological and near-surface hydrological system of the site investigation area. However, there are some remaining uncertainties regarding the interaction of deep and near-surface groundwater and surface water of importance for the understanding of the system: The groundwaters in till below Lake Eckarfjaerden, Lake Gaellbotraesket, Lake Fiskarfjaerden and Lake Bolundsfjaerden have high salinities. The hydrological and hydrochemical interpretations indicate that these waters are relict waters of mainly marine origin. From the perspective of the overall water balance, the water below the central parts of the lakes can be considered as stagnant. However, according to the hydrochemical interpretation, these waters also contain weak signatures of deep saline water. Rough chloride budget calculations for the Gaellbotraesket depression also raise the question of a possible upward flow of deep groundwater. No absolute conclusion can be drawn from the existing data analyses regarding the key question of whether there is a small ongoing upward flow of deep saline water. However, Lake Bolundsfjaerden is an exception where the clear downward flow gradient from the till to the bedrock excludes the possibility of an active deep saline source. The available data indicate that there are no discharge areas for flow systems involving deep bedrock groundwater in the northern part of the tectonic lens, where the repository is planned to be located (the so-called 'target area'). However, it can not be excluded that such discharge areas exist. Data indicate that the prevailing downward vertical flow gradients from the QD to the bedrock

  7. Description of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Per-Olof (Artesia Grundvattenkonsult AB, Taeby (Sweden))

    2008-12-15

    This report describes the modelling of the surface hydrology and near-surface hydrogeology that was performed for the final site descriptive model of Forsmark produced in the site investigation stage, SDM-Site Forsmark. The comprehensive investigation and monitoring programme forms a strong basis for the developed conceptual and descriptive model of the hydrological and near-surface hydrological system of the site investigation area. However, there are some remaining uncertainties regarding the interaction of deep and near-surface groundwater and surface water of importance for the understanding of the system: The groundwaters in till below Lake Eckarfjaerden, Lake Gaellbotraesket, Lake Fiskarfjaerden and Lake Bolundsfjaerden have high salinities. The hydrological and hydrochemical interpretations indicate that these waters are relict waters of mainly marine origin. From the perspective of the overall water balance, the water below the central parts of the lakes can be considered as stagnant. However, according to the hydrochemical interpretation, these waters also contain weak signatures of deep saline water. Rough chloride budget calculations for the Gaellbotraesket depression also raise the question of a possible upward flow of deep groundwater. No absolute conclusion can be drawn from the existing data analyses regarding the key question of whether there is a small ongoing upward flow of deep saline water. However, Lake Bolundsfjaerden is an exception where the clear downward flow gradient from the till to the bedrock excludes the possibility of an active deep saline source. The available data indicate that there are no discharge areas for flow systems involving deep bedrock groundwater in the northern part of the tectonic lens, where the repository is planned to be located (the so-called 'target area'). However, it can not be excluded that such discharge areas exist. Data indicate that the prevailing downward vertical flow gradients from the QD to

  8. Calibration of hydrological models using flow-duration curves

    Directory of Open Access Journals (Sweden)

    I. K. Westerberg

    2011-07-01

    Full Text Available The degree of belief we have in predictions from hydrologic models will normally depend on how well they can reproduce observations. Calibrations with traditional performance measures, such as the Nash-Sutcliffe model efficiency, are challenged by problems including: (1 uncertain discharge data, (2 variable sensitivity of different performance measures to different flow magnitudes, (3 influence of unknown input/output errors and (4 inability to evaluate model performance when observation time periods for discharge and model input data do not overlap. This paper explores a calibration method using flow-duration curves (FDCs to address these problems. The method focuses on reproducing the observed discharge frequency distribution rather than the exact hydrograph. It consists of applying limits of acceptability for selected evaluation points (EPs on the observed uncertain FDC in the extended GLUE approach. Two ways of selecting the EPs were tested – based on equal intervals of discharge and of volume of water. The method was tested and compared to a calibration using the traditional model efficiency for the daily four-parameter WASMOD model in the Paso La Ceiba catchment in Honduras and for Dynamic TOPMODEL evaluated at an hourly time scale for the Brue catchment in Great Britain. The volume method of selecting EPs gave the best results in both catchments with better calibrated slow flow, recession and evaporation than the other criteria. Observed and simulated time series of uncertain discharges agreed better for this method both in calibration and prediction in both catchments. An advantage with the method is that the rejection criterion is based on an estimation of the uncertainty in discharge data and that the EPs of the FDC can be chosen to reflect the aims of the modelling application, e.g. using more/less EPs at high/low flows. While the method appears less sensitive to epistemic input/output errors than previous use of limits of

  9. Hydrologic classification of rivers based on cluster analysis of dimensionless hydrologic signatures: Applications for environmental instream flows

    Science.gov (United States)

    Praskievicz, S. J.; Luo, C.

    2017-12-01

    Classification of rivers is useful for a variety of purposes, such as generating and testing hypotheses about watershed controls on hydrology, predicting hydrologic variables for ungaged rivers, and setting goals for river management. In this research, we present a bottom-up (based on machine learning) river classification designed to investigate the underlying physical processes governing rivers' hydrologic regimes. The classification was developed for the entire state of Alabama, based on 248 United States Geological Survey (USGS) stream gages that met criteria for length and completeness of records. Five dimensionless hydrologic signatures were derived for each gage: slope of the flow duration curve (indicator of flow variability), baseflow index (ratio of baseflow to average streamflow), rising limb density (number of rising limbs per unit time), runoff ratio (ratio of long-term average streamflow to long-term average precipitation), and streamflow elasticity (sensitivity of streamflow to precipitation). We used a Bayesian clustering algorithm to classify the gages, based on the five hydrologic signatures, into distinct hydrologic regimes. We then used classification and regression trees (CART) to predict each gaged river's membership in different hydrologic regimes based on climatic and watershed variables. Using existing geospatial data, we applied the CART analysis to classify ungaged streams in Alabama, with the National Hydrography Dataset Plus (NHDPlus) catchment (average area 3 km2) as the unit of classification. The results of the classification can be used for meeting management and conservation objectives in Alabama, such as developing statewide standards for environmental instream flows. Such hydrologic classification approaches are promising for contributing to process-based understanding of river systems.

  10. Surface and near-surface hydrological model of Olkiluoto island

    International Nuclear Information System (INIS)

    Karvonen, T.

    2008-04-01

    The aim of the study was to develop a 3D-model that calculates the overall water balance components of Olkiluoto Island in the present-day condition utilizing the existing extensive data sets available. The model links the unsaturated and saturated soil water in the overburden and groundwater in bedrock to a continuous pressure system. The parameterization of land use and vegetation was done in such a way that the model can later on be used for description of the past evolution of the overburden hydrology at the site and overburden's hydrological evolution in the future. Measured groundwater level in overburden tubes, pressure heads in shallow bedrock holes, snow depth, soil temperature, frost depth and discharge measurements were used in assessing the performance of the models in the calibration period (01.05.2001- 31.12.2005). Computed groundwater level variation can be characterized by variables ΔH MEAS and ΔH COMP , which are the difference between maximum and minimum measured and computed groundwater level value during the calibration period. Average ΔH MEAS for all tubes located in fine-textured till soil was 1.99 m and the corresponding computed value ΔH COMP was 1.83 m. Average ΔH MEAS for all tubes located in sandy till soil was 2.12 m and the corresponding computed value ΔH COMP was 1.93 m. The computed results indicate that in future studies it is necessary to divide the two most important soil types into several subclasses. In the present study the uncertainty and sensitivity analysis was carried out through a parameter uncertainty framework known as GLUE. According to the uncertainty analysis the average yearly runoff was around 175 mm a -1 and 50 % confidence limits were 155 and 195 mm a -1 . Measured average yearly runoff during the calibration period was 190 mm a -1 . Average yearly evapotranspiration estimate was 310 mm a -1 and the 50 % confidence limits were 290 and 330 mm a -1 . Average value for recharge through the bedrock system was 1

  11. Climate and surface water hydrology baseline data for Aurora Mine EIA

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    A climate and hydrology database was assembled to describe the existing climatic and surface water hydrological characteristics of the proposed Aurora Mine area in Leases 10, 12, 13, 31, and 34 east of the Athabasca River near Fort McKay. The study was based upon data available from the regional hydrometeorological monitoring network operated by the Governments of Canada and Alberta. The study also included the installation and monitoring of one climate station and five streamflow gauging stations on small watersheds in the area. The representative climatic and hydrologic characteristics of the area, including precipitation, evaporation, evapotranspiration, temperature and wind, were determined. Streamflow characteristics such as flood frequencies, low flow frequencies, water yield and flow durations representative of large gauged watersheds within the study area were also determined. The results offer a good basis for preliminary design of surface water management systems. It was recommended that the monitoring program should be continued to monitor potential environmental impacts of proposed development activities. 9 refs., 29 tabs., 32 figs.

  12. Scaling Hydrologic Exchange Flows and Biogeochemical Reactions from Bedforms to Basins

    Science.gov (United States)

    Harvey, J. W.; Gomez-Velez, J. D.

    2015-12-01

    River water moves in and out of the main channel along pathways that are perpendicular to the channel's main axis that flow across or beneath the ground surface. These hydrologic exchange flows (HEFs) are difficult to measure, yet no less important than a river's downstream flow, or exchanges with the atmosphere and deeper groundwater (Harvey and Gooseff, 2015, WRR). There are very few comprehensive investigations of exchange fluxes to understand patterns with river size and relative importance of specific types of exchanges. We used the physically based model NEXSS to simulate multiple scales of hyporheic flow and their cumulative effects on solute reaction in large basins (on the order of Chesapeake Bay basin or larger). Our goal was to explain where and when particular types of hyporheic flow are important in enhancing key biogeochemical reactions, such as organic carbon respiration and denitrification. Results demonstrate that hyporheic flux (expressed per unit area of streambed) varies surprisingly little across the continuum of first-order streams to eighth-order rivers, and vertical exchange beneath small bedforms dominates in comparison with lateral flow beneath gravel bars and meanders. Also, the river's entire volume is exchanged many times with hyporheic flow within a basin, and the turnover length (after one entire river volume is exchanged) is strongly influenced by hydrogeomorphic differences between physiographic regions as well as by river size. The cumulative effects on biogeochemical reactions were assessed using a the reaction significance factor, RSF, which computes the cumulative potential for hyporheic reactions using a dimensionless index that balances reaction progress in a single hyporheic flow path against overall processing efficiency of river turnover through hyporheic flow paths of that type. Reaction significance appears to be strongly dominated by hydrologic factors rather than biogeochemical factors, and seems to be dominated by

  13. Influence of slip-surface geometry on earth-flow deformation, Montaguto earth flow, southern Italy

    Science.gov (United States)

    Guerriero, L.; Coe, Jeffrey A.; Revellio, P.; Grelle, G.; Pinto, F.; Guadagno, F.

    2016-01-01

    We investigated relations between slip-surface geometry and deformational structures and hydrologic features at the Montaguto earth flow in southern Italy between 1954 and 2010. We used 25 boreholes, 15 static cone-penetration tests, and 22 shallow-seismic profiles to define the geometry of basal- and lateral-slip surfaces; and 9 multitemporal maps to quantify the spatial and temporal distribution of normal faults, thrust faults, back-tilted surfaces, strike-slip faults, flank ridges, folds, ponds, and springs. We infer that the slip surface is a repeating series of steeply sloping surfaces (risers) and gently sloping surfaces (treads). Stretching of earth-flow material created normal faults at risers, and shortening of earth-flow material created thrust faults, back-tilted surfaces, and ponds at treads. Individual pairs of risers and treads formed quasi-discrete kinematic zones within the earth flow that operated in unison to transmit pulses of sediment along the length of the flow. The locations of strike-slip faults, flank ridges, and folds were not controlled by basal-slip surface topography but were instead dependent on earth-flow volume and lateral changes in the direction of the earth-flow travel path. The earth-flow travel path was strongly influenced by inactive earth-flow deposits and pre-earth-flow drainages whose positions were determined by tectonic structures. The implications of our results that may be applicable to other earth flows are that structures with strikes normal to the direction of earth-flow motion (e.g., normal faults and thrust faults) can be used as a guide to the geometry of basal-slip surfaces, but that depths to the slip surface (i.e., the thickness of an earth flow) will vary as sediment pulses are transmitted through a flow.

  14. Measuring surface flow velocity with smartphones: potential for citizen observatories

    Science.gov (United States)

    Weijs, Steven V.; Chen, Zichong; Brauchli, Tristan; Huwald, Hendrik

    2014-05-01

    Stream flow velocity is an important variable for discharge estimation and research on sediment dynamics. Given the influence of the latter on rating curves (stage-discharge relations), and the relative scarcity of direct streamflow measurements, surface velocity measurements can offer important information for, e.g., flood warning, hydropower, and hydrological science and engineering in general. With the growing amount of sensing and computing power in the hands of more outdoorsy individuals, and the advances in image processing techniques, there is now a tremendous potential to obtain hydrologically relevant data from motivated citizens. This is the main focus of the interdisciplinary "WeSenseIt" project, a citizen observatory of water. In this subproject, we investigate the feasibility of stream flow surface velocity measurements from movie clips taken by (smartphone-) cameras. First results from movie-clip derived velocity information will be shown and compared to reference measurements.

  15. Real-Time Analysis and Forecasting of Multisite River Flow Using a Distributed Hydrological Model

    Directory of Open Access Journals (Sweden)

    Mingdong Sun

    2014-01-01

    Full Text Available A spatial distributed hydrological forecasting system was developed to promote the analysis of river flow dynamic state in a large basin. The research presented the real-time analysis and forecasting of multisite river flow in the Nakdong River Basin using a distributed hydrological model with radar rainfall forecast data. A real-time calibration algorithm of hydrological distributed model was proposed to investigate the particular relationship between the water storage and basin discharge. Demonstrate the approach of simulating multisite river flow using a distributed hydrological model couple with real-time calibration and forecasting of multisite river flow with radar rainfall forecasts data. The hydrographs and results exhibit that calibrated flow simulations are very approximate to the flow observation at all sites and the accuracy of forecasting flow is gradually decreased with lead times extending from 1 hr to 3 hrs. The flow forecasts are lower than the flow observation which is likely caused by the low estimation of radar rainfall forecasts. The research has well demonstrated that the distributed hydrological model is readily applicable for multisite real-time river flow analysis and forecasting in a large basin.

  16. Impact of vegetation dynamics on hydrological processes in a semi-arid basin by using a land surface-hydrology coupled model

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Yang; Lei, Huimin; Yang, Dawen; Huang, Maoyi; Liu, Dengfeng; Yuan, Xing

    2017-08-01

    Land surface models (LSMs) are widely used to understand the interactions between hydrological processes and vegetation dynamics, which is important for the attribution and prediction of regional hydrological variations. However, most LSMs have large uncertainties in their representations of ecohydrological processes due to deficiencies in hydrological parameterizations. In this study, the Community Land Model version 4 (CLM4) LSM was modified with an advanced runoff generation and flow routing scheme, resulting in a new land surface-hydrology coupled model, CLM-GBHM. Both models were implemented in the Wudinghe River Basin (WRB), which is a semi-arid basin located in the middle reaches of the Yellow River, China. Compared with CLM, CLM-GBHM increased the Nash Sutcliffe efficiency for daily river discharge simulation (1965–1969) from 0.03 to 0.23 and reduced the relative bias in water table depth simulations (2010–2012) from 32.4% to 13.4%. The CLM-GBHM simulations with static, remotely sensed and model-predicted vegetation conditions showed that the vegetation in the WRB began to recover in the 2000s due to the Grain for Green Program but had not reached the same level of vegetation cover as regions in natural eco-hydrological equilibrium. Compared with a simulation using remotely sensed vegetation cover, the simulation with a dynamic vegetation model that considers only climate-induced change showed a 10.3% increase in evapotranspiration, a 47.8% decrease in runoff, and a 62.7% and 71.3% deceleration in changing trend of the outlet river discharge before and after the year 2000, respectively. This result suggests that both natural and anthropogenic factors should be incorporated in dynamic vegetation models to better simulate the eco-hydrological cycle.

  17. Flow Regime Classification and Hydrological Characterization: A Case Study of Ethiopian Rivers

    Directory of Open Access Journals (Sweden)

    Belete Berhanu

    2015-06-01

    Full Text Available The spatiotemporal variability of a stream flow due to the complex interaction of catchment attributes and rainfall induce complexity in hydrology. Researchers have been trying to address this complexity with a number of approaches; river flow regime is one of them. The flow regime can be quantified by means of hydrological indices characterizing five components: magnitude, frequency, duration, timing, and rate of change of flow. Similarly, this study aimed to understand the flow variability of Ethiopian Rivers using the observed daily flow data from 208 gauging stations in the country. With this process, the Hierarchical Ward Clustering method was implemented to group the streams into three flow regimes (1 ephemeral, (2 intermittent, and (3 perennial. Principal component analysis (PCA is also applied as the second multivariate analysis tool to identify dominant hydrological indices that cause the variability in the streams. The mean flow per unit catchment area (QmAR and Base flow index (BFI show an incremental trend with ephemeral, intermittent and perennial streams. Whereas the number of mean zero flow days ratio (ZFI and coefficient of variation (CV show a decreasing trend with ephemeral to perennial flow regimes. Finally, the streams in the three flow regimes were characterized with the mean and standard deviation of the hydrological variables and the shape, slope, and scale of the flow duration curve. Results of this study are the basis for further understanding of the ecohydrological processes of the river basins in Ethiopia.

  18. Hydrology

    International Nuclear Information System (INIS)

    Obando G, E.

    1989-01-01

    Isotopical techniques are used in hydrology area for exploration, evaluation and exploration of water investigation. These techniques have been used successfully and are often the best or only means for providing certain hydrogeological parameters

  19. Improving the spatial representation of basin hydrology and flow processes in the SWAT model

    OpenAIRE

    Rathjens, Hendrik

    2014-01-01

    This dissertation aims at improving the spatial representation of basin hydrology and flow processes in the SWAT model. Die vorliegende Dissertation stellt die methodischen Grundlage zur räumlich differenzierten Modellierung mit dem Modell SWAT dar.

  20. Hydrological flow analysis at Yucca Mountain, Nevada. Final report

    International Nuclear Information System (INIS)

    1995-01-01

    This final report, prepared by Hydro Geo Chem staff for Los Alamos National Laboratory, summarizes work conducted by the company under Subcontract 52OHHOOI 5-3G, which was terminated by LANL effective 7 February 1995 for practical reasons, in that responsibilities for all tasks in the Statement of Work had been transitioned to LANL employees. The ultimate objective of this work is to characterize the movement of subsurface water in the vicinity of Yucca Mountain, Nevada. Data produced under this contract is to be used by the U.S. Department of Energy in its Yucca Mountain Site Characterization Project (YMP) to help determine hydrologic flows that may affect the performance of a potential nuclear waste,, repository. The data may be used in the licensing proceedings, and certain quality assurance procedures have thus been required. The work has focused on measuring the distribution of environmental tracers- chlorine-36, chlorine, and bromine-and on evaluating the depth to which these conservative solutes have percolated in the unsaturated zone at Yucca Mountain. The period of performance for the original Subcontract was I October 1994 to 31 December 1996. Obviously, we have not completed, nor are we expected to complete, all of the scope of work in the Subcontract. The following discussion summarizes progress made on the tasks outlined in the Statement of Work for this Subcontract Details of this work and all data acquired by Hydro Geo Chem for this Subcontract have, been systematically organized in logbooks and - laboratory notebooks (Appendices A and B). These documents have been structured to make it easy to trace the analytical history of a sample, from time of receipt to the final analytical results. The current status of this work and its relevance for the Yucca Mountain Project are described in a LANL report co-authored by Hydro Geo Chem staff

  1. Hydrological model for the transport of radioisotope in surface water

    International Nuclear Information System (INIS)

    Adoboah, E.K.

    2011-01-01

    The use of radioisotopes has gained grounds in Ghana as a result of the numerous benefits that could be derived from it. In Ghana, radioisotope materials are used for various purposes in a number of institutions. However, improper disposal of the waste poses threat to the environment. To evaluate the environmental impact of radioisotope pollution, mathematical models play a major role in predicting the pollution level in any medium. This study is concerned with the hydrological model for the transport of radioactive material in the river. The model was composed by employing partial differential equations, describing relevant physical processes evolution (water level, velocities and dissolved substances concentrations) that occurs in water bodies. The mass conservation and momentum laws, state equation and state transport equations are equation system basis. The explicit central difference scheme in space and a forward difference method in time were used for the evaluation of the generalized transport equation, the Advection-Dispersion Equation. A Matlab code was developed to predict the concentration of the radioactive contaminant at any particular time along the river and in a reservoir. The model was able to simulate accurately the various levels of radionuclide concentration changes in the flowing rivers as the flows are augmented by tributary inflows. (au)

  2. Singularities in Free Surface Flows

    Science.gov (United States)

    Thete, Sumeet Suresh

    Free surface flows where the shape of the interface separating two or more phases or liquids are unknown apriori, are commonplace in industrial applications and nature. Distribution of drop sizes, coalescence rate of drops, and the behavior of thin liquid films are crucial to understanding and enhancing industrial practices such as ink-jet printing, spraying, separations of chemicals, and coating flows. When a contiguous mass of liquid such as a drop, filament or a film undergoes breakup to give rise to multiple masses, the topological transition is accompanied with a finite-time singularity . Such singularity also arises when two or more masses of liquid merge into each other or coalesce. Thus the dynamics close to singularity determines the fate of about-to-form drops or films and applications they are involved in, and therefore needs to be analyzed precisely. The primary goal of this thesis is to resolve and analyze the dynamics close to singularity when free surface flows experience a topological transition, using a combination of theory, experiments, and numerical simulations. The first problem under consideration focuses on the dynamics following flow shut-off in bottle filling applications that are relevant to pharmaceutical and consumer products industry, using numerical techniques based on Galerkin Finite Element Methods (GFEM). The second problem addresses the dual flow behavior of aqueous foams that are observed in oil and gas fields and estimates the relevant parameters that describe such flows through a series of experiments. The third problem aims at understanding the drop formation of Newtonian and Carreau fluids, computationally using GFEM. The drops are formed as a result of imposed flow rates or expanding bubbles similar to those of piezo actuated and thermal ink-jet nozzles. The focus of fourth problem is on the evolution of thinning threads of Newtonian fluids and suspensions towards singularity, using computations based on GFEM and experimental

  3. Constraining the JULES land-surface model for different land-use types using citizen-science generated hydrological data

    Science.gov (United States)

    Chou, H. K.; Ochoa-Tocachi, B. F.; Buytaert, W.

    2017-12-01

    Community land surface models such as JULES are increasingly used for hydrological assessment because of their state-of-the-art representation of land-surface processes. However, a major weakness of JULES and other land surface models is the limited number of land surface parameterizations that is available. Therefore, this study explores the use of data from a network of catchments under homogeneous land-use to generate parameter "libraries" to extent the land surface parameterizations of JULES. The network (called iMHEA) is part of a grassroots initiative to characterise the hydrological response of different Andean ecosystems, and collects data on streamflow, precipitation, and several weather variables at a high temporal resolution. The tropical Andes are a useful case study because of the complexity of meteorological and geographical conditions combined with extremely heterogeneous land-use that result in a wide range of hydrological responses. We then calibrated JULES for each land-use represented in the iMHEA dataset. For the individual land-use types, the results show improved simulations of streamflow when using the calibrated parameters with respect to default values. In particular, the partitioning between surface and subsurface flows can be improved. But also, on a regional scale, hydrological modelling was greatly benefitted from constraining parameters using such distributed citizen-science generated streamflow data. This study demonstrates the modelling and prediction on regional hydrology by integrating citizen science and land surface model. In the context of hydrological study, the limitation of data scarcity could be solved indeed by using this framework. Improved predictions of such impacts could be leveraged by catchment managers to guide watershed interventions, to evaluate their effectiveness, and to minimize risks.

  4. Modeling erosion and sedimentation coupled with hydrological and overland flow processes at the watershed scale

    Science.gov (United States)

    Kim, Jongho; Ivanov, Valeriy Y.; Katopodes, Nikolaos D.

    2013-09-01

    A novel two-dimensional, physically based model of soil erosion and sediment transport coupled to models of hydrological and overland flow processes has been developed. The Hairsine-Rose formulation of erosion and deposition processes is used to account for size-selective sediment transport and differentiate bed material into original and deposited soil layers. The formulation is integrated within the framework of the hydrologic and hydrodynamic model tRIBS-OFM, Triangulated irregular network-based, Real-time Integrated Basin Simulator-Overland Flow Model. The integrated model explicitly couples the hydrodynamic formulation with the advection-dominated transport equations for sediment of multiple particle sizes. To solve the system of equations including both the Saint-Venant and the Hairsine-Rose equations, the finite volume method is employed based on Roe's approximate Riemann solver on an unstructured grid. The formulation yields space-time dynamics of flow, erosion, and sediment transport at fine scale. The integrated model has been successfully verified with analytical solutions and empirical data for two benchmark cases. Sensitivity tests to grid resolution and the number of used particle sizes have been carried out. The model has been validated at the catchment scale for the Lucky Hills watershed located in southeastern Arizona, USA, using 10 events for which catchment-scale streamflow and sediment yield data were available. Since the model is based on physical laws and explicitly uses multiple types of watershed information, satisfactory results were obtained. The spatial output has been analyzed and the driving role of topography in erosion processes has been discussed. It is expected that the integrated formulation of the model has the promise to reduce uncertainties associated with typical parameterizations of flow and erosion processes. A potential for more credible modeling of earth-surface processes is thus anticipated.

  5. Hydrology

    Science.gov (United States)

    Brutsaert, Wilfried

    2005-08-01

    Water in its different forms has always been a source of wonder, curiosity and practical concern for humans everywhere. Hydrology - An Introduction presents a coherent introduction to the fundamental principles of hydrology, based on the course that Wilfried Brutsaert has taught at Cornell University for the last thirty years. Hydrologic phenomena are dealt with at spatial and temporal scales at which they occur in nature. The physics and mathematics necessary to describe these phenomena are introduced and developed, and readers will require a working knowledge of calculus and basic fluid mechanics. The book will be invaluable as a textbook for entry-level courses in hydrology directed at advanced seniors and graduate students in physical science and engineering. In addition, the book will be more broadly of interest to professional scientists and engineers in hydrology, environmental science, meteorology, agronomy, geology, climatology, oceanology, glaciology and other earth sciences. Emphasis on fundamentals Clarification of the underlying physical processes Applications of fluid mechanics in the natural environment

  6. Analysis of heterogeneous hydrological properties of a mountainous hillslope using intensive water flow measurements

    Science.gov (United States)

    Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Mizuyama, Takahisa; Tsutsumi, Daizo

    2013-04-01

    Heterogeneous hydrological properties in a foot slope area of mountainous hillslopes should be assessed to understand hydrological phenomena and their effects on discharge and sediment transport. In this study, we analyzed the high-resolution and three-dimensional water movement data to clarify the hydrological process, including heterogeneous phenomena, in detail. We continuously monitored the soil matric pressure head, psi, using 111 tensiometers installed at grid intervals of approximately 1 meter within the soil mantle at the study hillslope. Under a no-rainfall condition, the existence of perennial groundwater seepage flow was detected by exfiltration flux and temporal psi waveforms, which showed delayed responses, only to heavy storm events, and gradual recession limbs. The seepage water spread in the downslope direction and supplied water constantly to the lower section of the slope. At some points in the center of the slope, a perched saturated area was detected in the middle of soil layer, while psi exhibited negative values above the bedrock surface. These phenomena could be inferred partly from the bedrock topography and the distribution of soil hydraulic conductivity assumed from the result of penetration test. At the peak of a rainfall event, on the other hand, continuous high pressure zones (i.e., psi > 50 cmH2O) were generated in the right and left sections of the slope. Both of these high pressure zones converged at the lower region, showing a sharp psi spike up to 100 cmH2O. Along the high pressure zones, flux vectors showed large values and water exfiltration, indicating the occurrence of preferential flow. Moreover, the preferential flow occurred within the area beneath the perched water, indicating the existence of a weathered bedrock layer. This layer had low permeability, which prevented the vertical infiltration of water in the upper part of the layer, but had high permeability as a result of the fractures distributed heterogeneously inside

  7. A surface hydrology model for regional vector borne disease models

    Science.gov (United States)

    Tompkins, Adrian; Asare, Ernest; Bomblies, Arne; Amekudzi, Leonard

    2016-04-01

    Small, sun-lit temporary pools that form during the rainy season are important breeding sites for many key mosquito vectors responsible for the transmission of malaria and other diseases. The representation of this surface hydrology in mathematical disease models is challenging, due to their small-scale, dependence on the terrain and the difficulty of setting soil parameters. Here we introduce a model that represents the temporal evolution of the aggregate statistics of breeding sites in a single pond fractional coverage parameter. The model is based on a simple, geometrical assumption concerning the terrain, and accounts for the processes of surface runoff, pond overflow, infiltration and evaporation. Soil moisture, soil properties and large-scale terrain slope are accounted for using a calibration parameter that sets the equivalent catchment fraction. The model is calibrated and then evaluated using in situ pond measurements in Ghana and ultra-high (10m) resolution explicit simulations for a village in Niger. Despite the model's simplicity, it is shown to reproduce the variability and mean of the pond aggregate water coverage well for both locations and validation techniques. Example malaria simulations for Uganda will be shown using this new scheme with a generic calibration setting, evaluated using district malaria case data. Possible methods for implementing regional calibration will be briefly discussed.

  8. Hydrologic Science and Satellite Measurements of Surface Water (Invited)

    Science.gov (United States)

    Alsdorf, D. E.; Mognard, N. M.; Lettenmaier, D. P.

    2010-12-01

    While significant advances continue to be made for satellite measurements of surface waters, important science and application opportunities remain. Examples include the following: (1) Our current methods of measuring floodwater dynamics are either sparsely distributed or temporally inadequate. As an example, flood depths are measured by using high water marks, which capture only the peak of the flood wave, not its temporal variability. (2) Discharge is well measured at individual points along stream networks using in-situ gauges, but these do not capture within-reach hydraulic variability such as the water surface slope changes on the rising and falling limbs of flood waves. (3) Just a 1.0 mm/day error in ET over the Congo Basin translates to a 35,000 m3/s discharge error. Knowing the discharge of the Congo River and its many tributaries should significantly improve our understanding of the water balance throughout the basin. The Congo is exemplary of many other basins around the globe. (4) Arctic hydrology is punctuated by millions of unmeasured lakes. Globally, there might be as many as 30 million lakes larger than a hectare. Storage changes in these lakes are nearly unknown, but in the Arctic such changes are likely an indication of global warming. (5) Well over 100 rivers cross international boundaries, yet the sharing of water data is poor. Overcoming this helps to better manage the entire river basin while also providing a better assessment of potential water related disasters. The Surface Water and Ocean Topography (SWOT, http://swot.jpl.nasa.gov/) mission is designed to meet these needs by providing global measurements of surface water hydrodynamics. SWOT will allow estimates of discharge in rivers wider than 100m (50m goal) and storage changes in water bodies larger than 250m by 250m (and likely as small as one hectare).

  9. Hydrologic Remote Sensing and Land Surface Data Assimilation

    Directory of Open Access Journals (Sweden)

    Hamid Moradkhani

    2008-05-01

    Full Text Available Accurate, reliable and skillful forecasting of key environmental variables such as soil moisture and snow are of paramount importance due to their strong influence on many water resources applications including flood control, agricultural production and effective water resources management which collectively control the behavior of the climate system. Soil moisture is a key state variable in land surface–atmosphere interactions affecting surface energy fluxes, runoff and the radiation balance. Snow processes also have a large influence on land-atmosphere energy exchanges due to snow high albedo, low thermal conductivity and considerable spatial and temporal variability resulting in the dramatic change on surface and ground temperature. Measurement of these two variables is possible through variety of methods using ground-based and remote sensing procedures. Remote sensing, however, holds great promise for soil moisture and snow measurements which have considerable spatial and temporal variability. Merging these measurements with hydrologic model outputs in a systematic and effective way results in an improvement of land surface model prediction. Data Assimilation provides a mechanism to combine these two sources of estimation. Much success has been attained in recent years in using data from passive microwave sensors and assimilating them into the models. This paper provides an overview of the remote sensing measurement techniques for soil moisture and snow data and describes the advances in data assimilation techniques through the ensemble filtering, mainly Ensemble Kalman filter (EnKF and Particle filter (PF, for improving the model prediction and reducing the uncertainties involved in prediction process. It is believed that PF provides a complete representation of the probability distribution of state variables of interests (according to sequential Bayes law and could be a strong alternative to EnKF which is subject to some

  10. Hydrologic Remote Sensing and Land Surface Data Assimilation.

    Science.gov (United States)

    Moradkhani, Hamid

    2008-05-06

    Accurate, reliable and skillful forecasting of key environmental variables such as soil moisture and snow are of paramount importance due to their strong influence on many water resources applications including flood control, agricultural production and effective water resources management which collectively control the behavior of the climate system. Soil moisture is a key state variable in land surface-atmosphere interactions affecting surface energy fluxes, runoff and the radiation balance. Snow processes also have a large influence on land-atmosphere energy exchanges due to snow high albedo, low thermal conductivity and considerable spatial and temporal variability resulting in the dramatic change on surface and ground temperature. Measurement of these two variables is possible through variety of methods using ground-based and remote sensing procedures. Remote sensing, however, holds great promise for soil moisture and snow measurements which have considerable spatial and temporal variability. Merging these measurements with hydrologic model outputs in a systematic and effective way results in an improvement of land surface model prediction. Data Assimilation provides a mechanism to combine these two sources of estimation. Much success has been attained in recent years in using data from passive microwave sensors and assimilating them into the models. This paper provides an overview of the remote sensing measurement techniques for soil moisture and snow data and describes the advances in data assimilation techniques through the ensemble filtering, mainly Ensemble Kalman filter (EnKF) and Particle filter (PF), for improving the model prediction and reducing the uncertainties involved in prediction process. It is believed that PF provides a complete representation of the probability distribution of state variables of interests (according to sequential Bayes law) and could be a strong alternative to EnKF which is subject to some limitations including the linear

  11. Water allocation assessment in low flow river under data scarce conditions: a study of hydrological simulation in Mediterranean basin.

    Science.gov (United States)

    Bangash, Rubab F; Passuello, Ana; Hammond, Michael; Schuhmacher, Marta

    2012-12-01

    River Francolí is a small river in Catalonia (northeastern Spain) with an average annual low flow (~2 m(3)/s). The purpose of the River Francolí watershed assessments is to support and inform region-wide planning efforts from the perspective of water protection, climate change and water allocation. In this study, a hydrological model of the Francolí River watershed was developed for use as a tool for watershed planning, water resource assessment, and ultimately, water allocation purposes using hydrological data from 2002 to 2006 inclusive. The modeling package selected for this application is DHI's MIKE BASIN. This model is a strategic scale water resource management simulation model, which includes modeling of both land surface and subsurface hydrological processes. Topographic, land use, hydrological, rainfall, and meteorological data were used to develop the model segmentation and input. Due to the unavailability of required catchment runoff data, the NAM rainfall-runoff model was used to calculate runoff of all the sub-watersheds. The results reveal a potential pressure on the availability of groundwater and surface water in the lower part of River Francolí as was expected by the IPCC for Mediterranean river basins. The study also revealed that due to the complex hydrological regime existing in the study area and data scarcity, a comprehensive physically based method was required to better represent the interaction between groundwater and surface water. The combined ArcGIS/MIKE BASIN models appear as a useful tool to assess the hydrological cycle and to better understand water allocation to different sectors in the Francolí River watershed. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Hydrologi

    DEFF Research Database (Denmark)

    Burcharth, Hans F.

    Hydro1ogi er den videnskab, der omhand1er jordens vand, dets forekomst, cirku1ation og forde1ing, dets kemiske og fysiske egenskaber samt indvirkning på omgivelserne, herunder dets relation ti1 alt liv på jorden. Således lyder en b1andt mange definitioner på begrebet hydrologi, og som man kan se...

  13. A spatial assessment of stream-flow characteristics and hydrologic ...

    African Journals Online (AJOL)

    2016-04-02

    Apr 2, 2016 ... the other site categories which did not significantly differ from each other. ... and detect altered hydrologic variables at different sites post dam construction. .... categories. Altered IHA Group 2 variables (magnitude and ..... catchment are dependent on the presence, position and distance from the dam.

  14. Hydrological classification of natural flow regimes to support environmental flow assessments in intensively regulated Mediterranean rivers, Segura River Basin (Spain).

    Science.gov (United States)

    Belmar, Oscar; Velasco, Josefa; Martinez-Capel, Francisco

    2011-05-01

    Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the "Ecological Limits of Hydrologic Alteration (ELOHA)". The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25 years of natural monthly flows (1980/81-2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indicated high redundancy among most hydrological indices, as well as two gradients: flow magnitude for mainstream rivers and temporal variability for tributary streams. A classification with eight flow-regime classes was chosen as the most easily interpretable in the Segura River Basin, which was supported by ANOSIM analyses. These classes can be simplified in 4 broader groups, with different seasonal discharge pattern: large rivers, perennial stable streams, perennial seasonal streams and intermittent and ephemeral streams. They showed a high degree of spatial cohesion, following a gradient associated with climatic aridity from NW to SE, and were well defined in terms of the fundamental variables in Mediterranean streams: magnitude and temporal variability of flows. Therefore, this classification is a fundamental tool to support water management and planning in the Segura River Basin. Future research will allow us to study the flow alteration-ecological response relationship for each river type, and set the basis to design scientifically credible environmental flows following the ELOHA framework.

  15. Comparison and Validation of Hydrological E-Flow Methods through Hydrodynamic Modelling

    Science.gov (United States)

    Kuriqi, Alban; Rivaes, Rui; Sordo-Ward, Alvaro; Pinheiro, António N.; Garrote, Luis

    2017-04-01

    Flow regime determines physical habitat conditions and local biotic configuration. The development of environmental flow guidelines to support the river integrity is becoming a major concern in water resources management. In this study, we analysed two sites located in southern part of Portugal, respectively at Odelouca and Ocreza Rivers, characterised by the Mediterranean climate. Both rivers are almost in pristine condition, not regulated by dams or other diversion construction. This study presents an analysis of the effect on fish habitat suitability by the implementation of different hydrological e-flow methods. To conduct this study we employed certain hydrological e-flow methods recommended by the European Small Hydropower Association (ESHA). River hydrology assessment was based on approximately 30 years of mean daily flow data, provided by the Portuguese Water Information System (SNIRH). The biological data, bathymetry, physical and hydraulic features, and the Habitat Suitability Index for fish species were collected from extensive field works. We followed the Instream Flow Incremental Methodology (IFIM) to assess the flow-habitat relationship taking into account the habitat suitability of different instream flow releases. Initially, we analysed fish habitat suitability based on natural conditions, and we used it as reference condition for other scenarios considering the chosen hydrological e-flow methods. We accomplished the habitat modelling through hydrodynamic analysis by using River-2D model. The same methodology was applied to each scenario by considering as input the e-flows obtained from each of the hydrological method employed in this study. This contribution shows the significance of ecohydrological studies in establishing a foundation for water resources management actions. Keywords: ecohydrology, e-flow, Mediterranean rivers, river conservation, fish habitat, River-2D, Hydropower.

  16. Evaluation of ecological instream flow using multiple ecological indicators with consideration of hydrological alterations

    Science.gov (United States)

    Zhang, Qiang; Gu, Xihui; Singh, Vijay P.; Chen, Xiaohong

    2015-10-01

    Dam-induced hydrological alterations and related ecological problems have been arousing considerable concern from hydrologists, ecologists, and policy-makers. The East River basin in China is the major provider of water resources for mega-cities within the Pearl River Delta and meets 80% of annual water demand of Hong Kong. In this study, ecodeficit and ecosurplus were analyzed to determine the ecological impact of water impoundments. Also, Do and DHRAM were employed to evaluate the degree of alteration of hydrological regimes, and ERHIs were analyzed to evaluate the influence of hydrological alterations on ecological diversity. Results indicate that: (1) the magnitude and frequency of high flows decrease and those of low flows increase due to the regulation of reservoirs; (2) variations of annual ecosurplus are mainly the result of precipitation changes and the annual ecodeficit is significantly influenced by reservoirs. However, ecodeficit and ecosurplus in other seasons, particularly autumn and winter, are more influenced by reservoir regulation; (3) impacts of reservoirs on hydrological regimes and eco-flow regimes are different from one station to another due to different degrees of influence of reservoirs on hydrological processes at different stations. The longer the distance between a reservoir and a hydrological station is, the weaker the influence the water reservoir has on the hydrological processes; (4) ecodeficit and ecosurplus can be accepted in the evaluation of alterations of hydrological processes at annual and seasonal time scales. Results of Shannon Index indicate decreasing biological diversity after the construction of water reservoirs, implying negative impacts of water reservoirs on biological diversity of a river basin and this should arouse considerable human concerns. This study provides a theoretical background for water resources management with consideration of eco-flow variations due to reservoir regulation in other highly

  17. Survey of hydrologic models and hydrologic data needs for tracking flow in the Rio Grande, north-central New Mexico, 2010

    Science.gov (United States)

    Tillery, Anne; Eggleston, Jack R.

    2012-01-01

    The six Middle Rio Grande Pueblos have prior and paramount rights to deliveries of water from the Rio Grande for their use. When the pueblos or the Bureau of Indian Affairs Designated Engineer identifies a need for additional flow on the Rio Grande, the Designated Engineer is tasked with deciding the timing and amount of releases of prior and paramount water from storage at El Vado Reservoir to meet the needs of the pueblos. Over the last three decades, numerous models have been developed by Federal, State, and local agencies in New Mexico to simulate, understand, and (or) manage flows in the Middle Rio Grande upstream from Elephant Butte Reservoir. In 2008, the Coalition of Six Middle Rio Grande Basin Pueblos entered into a cooperative agreement with the U.S. Geological Survey to conduct a comprehensive survey of these hydrologic models and their capacity to quantify and track various components of flow. The survey of hydrologic models provided in this report will help water-resource managers at the pueblos, as well as the Designated Engineer, make informed water-resource-management decisions that affect the prior and paramount water use. Analysis of 4 publicly available surface-water models and 13 publicly available groundwater models shows that, although elements from many models can be helpful in tracking flow in the Rio Grande, numerous data gaps and modeling needs indicate that accurate, consistent, and timely tracking of flow on the Rio Grande could be improved. Deficient or poorly constrained hydrologic variables are sources of uncertainty in hydrologic models that can be reduced with the acquisition of more refined data. Data gaps need to be filled to allow hydrologic models to be run on a real-time basis and thus ensure predictable water deliveries to meet needs for irrigation, domestic, stock, and other water uses. Timeliness of flow-data reporting is necessary to facilitate real-time model simulation, but even daily data are sometimes difficult to

  18. Hydrologic characteristics of freshwater mussel habitat: novel insights from modeled flows

    Science.gov (United States)

    Drew, C. Ashton; Eddy, Michele; Kwak, Thomas J.; Cope, W. Gregory; Augspurger, Tom

    2018-01-01

    The ability to model freshwater stream habitat and species distributions is limited by the spatially sparse flow data available from long-term gauging stations. Flow data beyond the immediate vicinity of gauging stations would enhance our ability to explore and characterize hydrologic habitat suitability. The southeastern USA supports high aquatic biodiversity, but threats, such as landuse alteration, climate change, conflicting water-resource demands, and pollution, have led to the imperilment and legal protection of many species. The ability to distinguish suitable from unsuitable habitat conditions, including hydrologic suitability, is a key criterion for successful conservation and restoration of aquatic species. We used the example of the critically endangered Tar River Spinymussel (Parvaspina steinstansana) and associated species to demonstrate the value of modeled flow data (WaterFALL™) to generate novel insights into population structure and testable hypotheses regarding hydrologic suitability. With ordination models, we: 1) identified all catchments with potentially suitable hydrology, 2) identified 2 distinct hydrologic environments occupied by the Tar River Spinymussel, and 3) estimated greater hydrological habitat niche breadth of assumed surrogate species associates at the catchment scale. Our findings provide the first demonstrated application of complete, continuous, regional modeled hydrologic data to freshwater mussel distribution and management. This research highlights the utility of modeling and data-mining methods to facilitate further exploration and application of such modeled environmental conditions to inform aquatic species management. We conclude that such an approach can support landscape-scale management decisions that require spatial information at fine resolution (e.g., enhanced National Hydrology Dataset catchments) and broad extent (e.g., multiple river basins).

  19. Socio-Hydrology of Channel Flows in Complex River Basins: Rivers, Canals, and Distributaries in Punjab, Pakistan

    Science.gov (United States)

    Wescoat, James L.; Siddiqi, Afreen; Muhammad, Abubakr

    2018-01-01

    This paper presents a socio-hydrologic analysis of channel flows in Punjab province of the Indus River basin in Pakistan. The Indus has undergone profound transformations, from large-scale canal irrigation in the mid-nineteenth century to partition and development of the international river basin in the mid-twentieth century, systems modeling in the late-twentieth century, and new technologies for discharge measurement and data analytics in the early twenty-first century. We address these processes through a socio-hydrologic framework that couples historical geographic and analytical methods at three levels of flow in the Punjab. The first level assesses Indus River inflows analysis from its origins in 1922 to the present. The second level shows how river inflows translate into 10-daily canal command deliveries that vary widely in their conformity with canal entitlements. The third level of analysis shows how new flow measurement technologies raise questions about the performance of established methods of water scheduling (warabandi) on local distributaries. We show how near real-time measurement sheds light on the efficiency and transparency of surface water management. These local socio-hydrologic changes have implications in turn for the larger scales of canal and river inflow management in complex river basins.

  20. The ecological limits of hydrologic alteration (ELOHA): A new framework for developing regional environmental flow standards

    Science.gov (United States)

    Poff, N.L.; Richter, B.D.; Arthington, A.H.; Bunn, S.E.; Naiman, R.J.; Kendy, E.; Acreman, M.; Apse, C.; Bledsoe, B.P.; Freeman, Mary C.; Henriksen, J.; Jacobson, R.B.; Kennen, J.G.; Merritt, D.M.; O'Keeffe, J. H.; Olden, J.D.; Rogers, K.; Tharme, R.E.; Warner, A.

    2010-01-01

    The flow regime is a primary determinant of the structure and function of aquatic and riparian ecosystems for streams and rivers. Hydrologic alteration has impaired riverine ecosystems on a global scale, and the pace and intensity of human development greatly exceeds the ability of scientists to assess the effects on a river-by-river basis. Current scientific understanding of hydrologic controls on riverine ecosystems and experience gained from individual river studies support development of environmental flow standards at the regional scale. 2. This paper presents a consensus view from a group of international scientists on a new framework for assessing environmental flow needs for many streams and rivers simultaneously to foster development and implementation of environmental flow standards at the regional scale. This framework, the ecological limits of hydrologic alteration (ELOHA), is a synthesis of a number of existing hydrologic techniques and environmental flow methods that are currently being used to various degrees and that can support comprehensive regional flow management. The flexible approach allows scientists, water-resource managers and stakeholders to analyse and synthesise available scientific information into ecologically based and socially acceptable goals and standards for management of environmental flows. 3. The ELOHA framework includes the synthesis of existing hydrologic and ecological databases from many rivers within a user-defined region to develop scientifically defensible and empirically testable relationships between flow alteration and ecological responses. These relationships serve as the basis for the societally driven process of developing regional flow standards. This is to be achieved by first using hydrologic modelling to build a 'hydrologic foundation' of baseline and current hydrographs for stream and river segments throughout the region. Second, using a set of ecologically relevant flow variables, river segments within the

  1. A Framework to Assess the Cumulative Hydrological Impacts of Dams on flow Regime

    Science.gov (United States)

    Wang, Y.; Wang, D.

    2016-12-01

    In this study we proposed a framework to assess the cumulative impact of dams on hydrological regime, and the impacts of the Three Gorges Dam on flow regime in Yangtze River were investigated with the framework. We reconstructed the unregulated flow series to compare with the regulated flow series in the same period. Eco-surplus and eco-deficit and the Indicators of Hydrologic Alteration parameters were used to examine the hydrological regime change. Among IHA parameters, Wilcoxon signed-rank test and Principal Components Analysis identified the representative indicators of hydrological alterations. Eco-surplus and eco-deficit showed that the reservoir also changed the seasonal regime of the flows in autumn and winter. Annual extreme flows and October flows changes lead to negative ecological implications downstream from the Three Gorges Dam. Ecological operation for the Three Gorges Dam is necessary to mitigate the negative effects on the river ecosystem in the middle reach of Yangtze River. The framework proposed here could be a robust method to assess the cumulative impacts of reservoir operation.

  2. Dynamically adaptive data-driven simulation of extreme hydrological flows

    Science.gov (United States)

    Kumar Jain, Pushkar; Mandli, Kyle; Hoteit, Ibrahim; Knio, Omar; Dawson, Clint

    2018-02-01

    Hydrological hazards such as storm surges, tsunamis, and rainfall-induced flooding are physically complex events that are costly in loss of human life and economic productivity. Many such disasters could be mitigated through improved emergency evacuation in real-time and through the development of resilient infrastructure based on knowledge of how systems respond to extreme events. Data-driven computational modeling is a critical technology underpinning these efforts. This investigation focuses on the novel combination of methodologies in forward simulation and data assimilation. The forward geophysical model utilizes adaptive mesh refinement (AMR), a process by which a computational mesh can adapt in time and space based on the current state of a simulation. The forward solution is combined with ensemble based data assimilation methods, whereby observations from an event are assimilated into the forward simulation to improve the veracity of the solution, or used to invert for uncertain physical parameters. The novelty in our approach is the tight two-way coupling of AMR and ensemble filtering techniques. The technology is tested using actual data from the Chile tsunami event of February 27, 2010. These advances offer the promise of significantly transforming data-driven, real-time modeling of hydrological hazards, with potentially broader applications in other science domains.

  3. Dynamically adaptive data-driven simulation of extreme hydrological flows

    KAUST Repository

    Kumar Jain, Pushkar

    2017-12-27

    Hydrological hazards such as storm surges, tsunamis, and rainfall-induced flooding are physically complex events that are costly in loss of human life and economic productivity. Many such disasters could be mitigated through improved emergency evacuation in real-time and through the development of resilient infrastructure based on knowledge of how systems respond to extreme events. Data-driven computational modeling is a critical technology underpinning these efforts. This investigation focuses on the novel combination of methodologies in forward simulation and data assimilation. The forward geophysical model utilizes adaptive mesh refinement (AMR), a process by which a computational mesh can adapt in time and space based on the current state of a simulation. The forward solution is combined with ensemble based data assimilation methods, whereby observations from an event are assimilated into the forward simulation to improve the veracity of the solution, or used to invert for uncertain physical parameters. The novelty in our approach is the tight two-way coupling of AMR and ensemble filtering techniques. The technology is tested using actual data from the Chile tsunami event of February 27, 2010. These advances offer the promise of significantly transforming data-driven, real-time modeling of hydrological hazards, with potentially broader applications in other science domains.

  4. Evaluation of Airborne Lidar Elevation Surfaces for Propagation of Coastal Inundation: The Importance of Hydrologic Connectivity

    Directory of Open Access Journals (Sweden)

    Sandra Poppenga

    2015-09-01

    Full Text Available Detailed information about coastal inundation is vital to understanding dynamic and populated areas that are impacted by storm surge and flooding. To understand these natural hazard risks, lidar elevation surfaces are frequently used to model inundation in coastal areas. A single-value surface method is sometimes used to inundate areas in lidar elevation surfaces that are below a specified elevation value. However, such an approach does not take into consideration hydrologic connectivity between elevation grids cells resulting in inland areas that should be hydrologically connected to the ocean, but are not. Because inland areas that should drain to the ocean are hydrologically disconnected by raised features in a lidar elevation surface, simply raising the water level to propagate coastal inundation will lead to inundation uncertainties. We took advantage of this problem to identify hydrologically disconnected inland areas to point out that they should be considered for coastal inundation, and that a lidar-based hydrologic surface should be developed with hydrologic connectivity prior to inundation analysis. The process of achieving hydrologic connectivity with hydrologic-enforcement is not new, however, the application of hydrologically-enforced lidar elevation surfaces for improved coastal inundation mapping as approached in this research is innovative. In this article, we propagated a high-resolution lidar elevation surface in coastal Staten Island, New York to demonstrate that inland areas lacking hydrologic connectivity to the ocean could potentially be included in inundation delineations. For inland areas that were hydrologically disconnected, we evaluated if drainage to the ocean was evident, and calculated an area exceeding 11 ha (~0.11 km2 that could be considered in inundation delineations. We also assessed land cover for each inland area to determine the type of physical surfaces that would be potentially impacted if the inland areas

  5. Evaluation of airborne lidar elevation surfaces for propagation of coastal inundation: the importance of hydrologic connectivity

    Science.gov (United States)

    Poppenga, Sandra K.; Worstell, Bruce B.

    2015-01-01

    Detailed information about coastal inundation is vital to understanding dynamic and populated areas that are impacted by storm surge and flooding. To understand these natural hazard risks, lidar elevation surfaces are frequently used to model inundation in coastal areas. A single-value surface method is sometimes used to inundate areas in lidar elevation surfaces that are below a specified elevation value. However, such an approach does not take into consideration hydrologic connectivity between elevation grids cells resulting in inland areas that should be hydrologically connected to the ocean, but are not. Because inland areas that should drain to the ocean are hydrologically disconnected by raised features in a lidar elevation surface, simply raising the water level to propagate coastal inundation will lead to inundation uncertainties. We took advantage of this problem to identify hydrologically disconnected inland areas to point out that they should be considered for coastal inundation, and that a lidar-based hydrologic surface should be developed with hydrologic connectivity prior to inundation analysis. The process of achieving hydrologic connectivity with hydrologic-enforcement is not new, however, the application of hydrologically-enforced lidar elevation surfaces for improved coastal inundation mapping as approached in this research is innovative. In this article, we propagated a high-resolution lidar elevation surface in coastal Staten Island, New York to demonstrate that inland areas lacking hydrologic connectivity to the ocean could potentially be included in inundation delineations. For inland areas that were hydrologically disconnected, we evaluated if drainage to the ocean was evident, and calculated an area exceeding 11 ha (~0.11 km2) that could be considered in inundation delineations. We also assessed land cover for each inland area to determine the type of physical surfaces that would be potentially impacted if the inland areas were considered as

  6. Flood Simulations and Uncertainty Analysis for the Pearl River Basin Using the Coupled Land Surface and Hydrological Model System

    Directory of Open Access Journals (Sweden)

    Yongnan Zhu

    2017-06-01

    Full Text Available The performances of hydrological simulations for the Pearl River Basin in China were analysed using the Coupled Land Surface and Hydrological Model System (CLHMS. Three datasets, including East Asia (EA, high-resolution gauge satellite-merged China Merged Precipitation Analysis (CMPA-Daily, and the Asian Precipitation Highly-Resolved Observational Data Integration Towards Evaluation (APHRODITE daily precipitation were used to drive the CLHMS model to simulate daily hydrological processes from 1998 to 2006. The results indicate that the precipitation data was the most important source of uncertainty in the hydrological simulation. The simulated streamflow driven by the CMPA-Daily agreed well with observations, with a Pearson correlation coefficient (PMC greater than 0.70 and an index of agreement (IOA similarity coefficient greater than 0.82 at Liuzhou, Shijiao, and Wuzhou Stations. Comparison of the Nash-Sutcliffe efficiency coefficient (NSE shows that the peak flow simulation ability of CLHMS driven with the CMPA-Daily rainfall is relatively superior to that with the EA and APHRODITE datasets. The simulation results for the high-flow periods in 1998 and 2005 indicate that the CLHMS is promising for its future application in the flood simulation and prediction.

  7. Evaluation of ecological instream flow considering hydrological alterations in the Yellow River basin, China

    Science.gov (United States)

    Zhang, Qiang; Zhang, Zongjiao; Shi, Peijun; Singh, Vijay P.; Gu, Xihui

    2018-01-01

    The Yellow River is the second largest river in China and is the important source for water supply in the northwestern and northern China. It is often regarded as the mother river of China. Owing to climatic change and intensifying human activities, such as increasing withdrawal of water for meeting growing agricultural irrigation needs since 1986, the flow of Yellow River has decreased, with serious impacts on the ecological environment. Using multiple hydrological indicators and Flow Duration Curve (DFC)-based ecodeficit and ecosurplus, this study investigates the impact of hydrological alterations, such as the impact of water reservoirs or dams, on downstream ecological instream flow. Results indicate that: (1) due to the impoundment and hydrological regulations of water reservoirs, occurrence rates and magnitudes of high flow regimes have decreased and the decrease is also found in the magnitudes of low flow events. These changes tend to be more evident from the upper to the lower Yellow River basin; (2) human activities tend to enhance the instream flow variability, particularly after the 1980s;(3) the ecological environment in different parts of the Yellow River basin is under different degrees of ecological risk. In general, lower to higher ecological risk can be detected due to hydrological alterations from the upper to the lower Yellow River basin. This shows that conservation of ecological environment and river health is facing a serious challenge in the lower Yellow River basin; (4) ecological instream flow indices, such as ecodeficit and ecosurplus, and IHA32 hydrological indicators are in strong relationships, suggesting that ecodeficit and ecosurplus can be regarded as appropriate ecological indicators for developing measures for mitigating the adverse impact of human activities on the conservation of ecological environment in the Yellow River basin.

  8. The observed sensitivity of the global hydrological cycle to changes in surface temperature

    International Nuclear Information System (INIS)

    Arkin, Phillip A; Janowiak, John; Smith, Thomas M; Sapiano, Mathew R P

    2010-01-01

    Climate models project large changes in global surface temperature in coming decades that are expected to be accompanied by significant changes in the global hydrological cycle. Validation of model simulations is essential to support their use in decision making, but observing the elements of the hydrological cycle is challenging, and model-independent global data sets exist only for precipitation. We compute the sensitivity of the global hydrological cycle to changes in surface temperature using available global precipitation data sets and compare the results against the sensitivities derived from model simulations of 20th century climate. The implications of the results for the global climate observing system are discussed.

  9. Report on Hydrologic Flow in Low-Permeability Media

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hui-Hai; Birkholzer, Jens

    2013-11-13

    We demonstrate that under normal conditions (under which there are no intersections between tunnels/drifts and conductive geological structures, such as faults), the water flow velocity in the damage zone, as a result of non-Darcian flow behavior, is extremely small such that solute transport is dominated by diffusion, rather than advection. We show that unless non-Darcian flow behavior is considered, significant errors can occur in the “measured” relative-permeability values. We propose a hypothesis to consider the temperature impact based on limited test results from the petroleum literature. To consider the bedding effects, we present an empirical relationship between water flux and hydraulic gradient for non-Darcian water flow in anisotropic cases.

  10. Integrating remotely sensed surface water extent into continental scale hydrology

    NARCIS (Netherlands)

    Revilla-Romero, Beatriz; Wanders, Niko; Burek, Peter; Salamon, Peter; de Roo, Ad

    2016-01-01

    In hydrological forecasting, data assimilation techniques are employed to improve estimates of initial conditions to update incorrect model states with observational data. However, the limited availability of continuous and up-to-date ground streamflow data is one of the main constraints for

  11. Hydrodynamic modeling of hydrologic surface connectivity within a coastal river-floodplain system

    Science.gov (United States)

    Castillo, C. R.; Guneralp, I.

    2017-12-01

    Hydrologic surface connectivity (HSC) within river-floodplain environments is a useful indicator of the overall health of riparian habitats because it allows connections amongst components/landforms of the riverine landscape system to be quantified. Overbank flows have traditionally been the focus for analyses concerned with river-floodplain connectivity, but recent works have identified the large significance from sub-bankfull streamflows. Through the use of morphometric analysis and a digital elevation model that is relative to the river water surface, we previously determined that >50% of the floodplain for Mission River on the Coastal Bend of Texas becomes connected to the river at streamflows well-below bankfull conditions. Guided by streamflow records, field-based inundation data, and morphometric analysis; we develop a two-dimensional hydrodynamic model for lower portions of Mission River Floodplain system. This model not only allows us to analyze connections induced by surface water inundation, but also other aspects of the hydrologic connectivity concept such as exchanges of sediment and energy between the river and its floodplain. We also aggregate hydrodynamic model outputs to an object/landform level in order to analyze HSC and associated attributes using measures from graph/network theory. Combining physically-based hydrodynamic models with object-based and graph theoretical analyses allow river-floodplain connectivity to be quantified in a consistent manner with measures/indicators commonly used in landscape analysis. Analyzes similar to ours build towards the establishment of a formal framework for analyzing river-floodplain interaction that will ultimately serve to inform the management of riverine/floodplain environments.

  12. The lower San Pedro River: hydrology and flow restoration for biodiversity conservation

    Science.gov (United States)

    Jeanmarie Haney

    2005-01-01

    The lower San Pedro River, downstream from Benson, is a nearly unfragmented habitat containing perennial flow reaches that support riparian vegetation that serve as “stepping stones” for migratory species. The Nature Conservancy has purchased farm properties and retired agricultural pumping along the lower river, based largely on results from hydrologic analyses...

  13. Hydrological heterogeneity in Mediterranean reclaimed slopes: runoff and sediment yield at the patch and slope scales along a gradient of overland flow

    Directory of Open Access Journals (Sweden)

    L. Merino-Martín

    2012-05-01

    Full Text Available Hydrological heterogeneity is recognized as a fundamental ecosystem attribute in drylands controlling the flux of water and energy through landscapes. Therefore, mosaics of runoff and sediment source patches and sinks are frequently identified in these dry environments. There is a remarkable scarcity of studies about hydrological spatial heterogeneity in restored slopes, where ecological succession and overland flow are interacting. We conducted field research to study the hydrological role of patches and slopes along an "overland flow gradient" (gradient of overland flow routing through the slopes caused by different amounts of run-on coming from upslope in three reclaimed mining slopes of Mediterranean-continental climate. We found that runoff generation and routing in non-rilled slopes showed a pattern of source and sink areas of runoff. Such hydrological microenvironments were associated with seven vegetation patches (characterized by plant community types and cover. Two types of sink patches were identified: shrub Genista scorpius patches could be considered as "deep sinks", while patches where the graminoids Brachypodium retusum and Lolium perenne dominate were classified as "surface sinks" or "runoff splays". A variety of source patches were also identified spanning from "extreme sources" (Medicago sativa patches; equivalent to bare soil to "poor sources" (areas scattered by dwarf-shrubs of Thymus vulgaris or herbaceous tussocks of Dactylis glomerata. Finally, we identified the volume of overland flow routing along the slope as a major controlling factor of "hydrological diversity" (heterogeneity of hydrological behaviours quantified as Shannon diversity index: when overland flow increases at the slope scale hydrological diversity diminishes.

  14. A model of hydrological and mechanical feedbacks of preferential fissure flow in a slow-moving landslide

    Directory of Open Access Journals (Sweden)

    D. M. Krzeminska

    2013-03-01

    Full Text Available The importance of hydrological processes for landslide activity is generally accepted. However, the relationship between precipitation, hydrological responses and movement is not straightforward. Groundwater recharge is mostly controlled by the hydrological material properties and the structure (e.g., layering, preferential flow paths such as fissures of the unsaturated zone. In slow-moving landslides, differential displacements caused by the bedrock structure complicate the hydrological regime due to continuous opening and closing of the fissures, creating temporary preferential flow paths systems for infiltration and groundwater drainage. The consecutive opening and closing of fissure aperture control the formation of a critical pore water pressure by creating dynamic preferential flow paths for infiltration and groundwater drainage. This interaction may explain the seasonal nature of the slow-moving landslide activity, including the often observed shifts and delays in hydrological responses when compared to timing, intensity and duration of precipitation. The main objective of this study is to model the influence of fissures on the hydrological dynamics of slow-moving landslide and the dynamic feedbacks between fissures, hydrology and slope stability. For this we adapt the spatially distributed hydrological and slope stability model (STARWARS to account for geotechnical and hydrological feedbacks, linking between hydrological response of the landside and the dynamics of the fissure network and applied the model to the hydrologically controlled Super-Sauze landslide (South French Alps.

  15. Design and development of a smart aerial platform for surface hydrological measurements

    Science.gov (United States)

    Tauro, F.; Pagano, C.; Porfiri, M.; Grimaldi, S.

    2013-12-01

    Currently available experimental methodologies for surface hydrological monitoring rely on the use of intrusive sensing technologies which tend to provide local rather than distributed information on the flow physics. In this context, drawbacks deriving from the use of invasive instrumentation are partially alleviated by Large Scale Particle Image Velocimetry (LSPIV). LSPIV is based on the use of cameras mounted on masts along river banks which capture images of artificial tracers or naturally occurring objects floating on water surfaces. Images are then georeferenced and the displacement of groups of floating tracers statistically analyzed to reconstruct flow velocity maps at specific river cross-sections. In this work, we mitigate LSPIV spatial limitations and inaccuracies due to image calibration by designing and developing a smart platform which integrates digital acquisition system and laser calibration units onboard of a custom-built quadricopter. The quadricopter is designed to be lightweight, low cost as compared to kits available on the market, highly customizable, and stable to guarantee minimal vibrations during image acquisition. The onboard digital system includes an encased GoPro Hero 3 camera whose axis is constantly kept orthogonal to the water surface by means of an in-house developed gimbal. The gimbal is connected to the quadricopter through a shock absorber damping device which further reduces eventual vibrations. Image calibration is performed through laser units mounted at known distances on the quadricopter landing apparatus. The vehicle can be remotely controlled by the open-source Ardupilot microcontroller. Calibration tests and field experiments are conducted in outdoor environments to assess the feasibility of using the smart platform for acquisition of high quality images of natural streams. Captured images are processed by LSPIV algorithms and average flow velocities are compared to independently acquired flow estimates. Further, videos

  16. Efficient uncertainty quantification in fully-integrated surface and subsurface hydrologic simulations

    Science.gov (United States)

    Miller, K. L.; Berg, S. J.; Davison, J. H.; Sudicky, E. A.; Forsyth, P. A.

    2018-01-01

    Although high performance computers and advanced numerical methods have made the application of fully-integrated surface and subsurface flow and transport models such as HydroGeoSphere common place, run times for large complex basin models can still be on the order of days to weeks, thus, limiting the usefulness of traditional workhorse algorithms for uncertainty quantification (UQ) such as Latin Hypercube simulation (LHS) or Monte Carlo simulation (MCS), which generally require thousands of simulations to achieve an acceptable level of accuracy. In this paper we investigate non-intrusive polynomial chaos for uncertainty quantification, which in contrast to random sampling methods (e.g., LHS and MCS), represents a model response of interest as a weighted sum of polynomials over the random inputs. Once a chaos expansion has been constructed, approximating the mean, covariance, probability density function, cumulative distribution function, and other common statistics as well as local and global sensitivity measures is straightforward and computationally inexpensive, thus making PCE an attractive UQ method for hydrologic models with long run times. Our polynomial chaos implementation was validated through comparison with analytical solutions as well as solutions obtained via LHS for simple numerical problems. It was then used to quantify parametric uncertainty in a series of numerical problems with increasing complexity, including a two-dimensional fully-saturated, steady flow and transient transport problem with six uncertain parameters and one quantity of interest; a one-dimensional variably-saturated column test involving transient flow and transport, four uncertain parameters, and two quantities of interest at 101 spatial locations and five different times each (1010 total); and a three-dimensional fully-integrated surface and subsurface flow and transport problem for a small test catchment involving seven uncertain parameters and three quantities of interest at

  17. Increasing the reliability of the Olkiluoto surface and near-surface hydrological model

    International Nuclear Information System (INIS)

    Karvonen, T.

    2009-05-01

    The aim of the study was to improve the reliability of the Olkiluoto surface hydrological model that calculates the overall water balance components of Olkiluoto Island. ONKALO and Korvensuo reservoir were added as explicit structures to the model. The model links the unsaturated and saturated soil water in the overburden and groundwater in bedrock to a continuous pressure system. With the model it is possible to evaluate the influence of water leaking to ONKALO on groundwater level in overburden soils and pressure head in shallow bedrock drillholes. Anisotropy was added to the surface hydrological model and several model runs were carried out using anisotropy factors 1, 5 and 10. Anisotropy factor of 10 is used in the 2008 version of the deep hydrogeological model and the same anisotropy will be used in future calculations of the surface hydrological model to ensure consistency of the parameter values in the two models. The correspondence between measured and computed groundwater levels has been improved due to new soil type delineation and the calibration of the soil water retention curve parameters. Computed groundwater level variation can be characterized by a measure ΔH COMP , which is difference between maximum and minimum value during the calibration period. Average ΔH COMP in groundwater tubes was 1.98 m and the corresponding measured value ΔH MEAS was 2.08 m, i.e. the difference between measured and computed value was around 0.1 m (0.16 m in the 2007 version). Temporal variation (difference between maximum and minimum pressure head) was simulated well also in most of the shallow bedrock drillholes. ONKALO was added to the 2008 version of the Olkiluoto surface hydrological model. Influence of ONKALO is taken into account by giving the total discharge as input data from existing measurements or from calculations of the deep hydrogeological model of the Olkiluoto Island. The computed results show that ONKALO has a temporal effect on groundwater level in

  18. Development of the Hydrological-Ecological Integrated watershed Flow Model (HEIFLOW): an application to the Heihe River Basin

    Science.gov (United States)

    Tian, Y.; Zheng, Y.; Zheng, C.; Han, F., Sr.

    2017-12-01

    Physically based and fully-distributed integrated hydrological models (IHMs) can quantitatively depict hydrological processes, both surface and subsurface, with sufficient spatial and temporal details. However, the complexity involved in pre-processing data and setting up models seriously hindered the wider application of IHMs in scientific research and management practice. This study introduces our design and development of Visual HEIFLOW, hereafter referred to as VHF, a comprehensive graphical data processing and modeling system for integrated hydrological simulation. The current version of VHF has been structured to accommodate an IHM named HEIFLOW (Hydrological-Ecological Integrated watershed-scale FLOW model). HEIFLOW is a model being developed by the authors, which has all typical elements of physically based and fully-distributed IHMs. It is based on GSFLOW, a representative integrated surface water-groundwater model developed by USGS. HEIFLOW provides several ecological modules that enable to simulate growth cycle of general vegetation and special plants (maize and populus euphratica). VHF incorporates and streamlines all key steps of the integrated modeling, and accommodates all types of GIS data necessary to hydrological simulation. It provides a GIS-based data processing framework to prepare an IHM for simulations, and has functionalities to flexibly display and modify model features (e.g., model grids, streams, boundary conditions, observational sites, etc.) and their associated data. It enables visualization and various spatio-temporal analyses of all model inputs and outputs at different scales (i.e., computing unit, sub-basin, basin, or user-defined spatial extent). The above system features, as well as many others, can significantly reduce the difficulty and time cost of building and using a complex IHM. The case study in the Heihe River Basin demonstrated the applicability of VHF for large scale integrated SW-GW modeling. Visualization and spatial

  19. Extracting Hydrologic Understanding from the Unique Space-time Sampling of the Surface Water and Ocean Topography (SWOT) Mission

    Science.gov (United States)

    Nickles, C.; Zhao, Y.; Beighley, E.; Durand, M. T.; David, C. H.; Lee, H.

    2017-12-01

    The Surface Water and Ocean Topography (SWOT) satellite mission is jointly developed by NASA, the French space agency (CNES), with participation from the Canadian and UK space agencies to serve both the hydrology and oceanography communities. The SWOT mission will sample global surface water extents and elevations (lakes/reservoirs, rivers, estuaries, oceans, sea and land ice) at a finer spatial resolution than is currently possible enabling hydrologic discovery, model advancements and new applications that are not currently possible or likely even conceivable. Although the mission will provide global cover, analysis and interpolation of the data generated from the irregular space/time sampling represents a significant challenge. In this study, we explore the applicability of the unique space/time sampling for understanding river discharge dynamics throughout the Ohio River Basin. River network topology, SWOT sampling (i.e., orbit and identified SWOT river reaches) and spatial interpolation concepts are used to quantify the fraction of effective sampling of river reaches each day of the three-year mission. Streamflow statistics for SWOT generated river discharge time series are compared to continuous daily river discharge series. Relationships are presented to transform SWOT generated streamflow statistics to equivalent continuous daily discharge time series statistics intended to support hydrologic applications using low-flow and annual flow duration statistics.

  20. Simulation of gas compressible flow by free surface water flow

    International Nuclear Information System (INIS)

    Altafini, C.R.; Silva Ferreira, R.T. da

    1981-01-01

    The analogy between the water flow with a free surface and the compressible fluid flow, commonly called hydraulic analogy, is analyzed and its limitations are identified. The water table is the equipment used for this simulation, which allows the quatitative analysis of subsonic and supersonic flow with a low cost apparatus. The hydraulic analogy is applied to subsonic flow around circular cylinders and supersonic flow around cones. The results are compared with available theoretical and experimental data and a good agreement is achieved. (Author) [pt

  1. Balancing practicality and hydrologic realism: a parsimonious approach for simulating rapid groundwater recharge via unsaturated-zone preferential flow

    Science.gov (United States)

    Mirus, Benjamin B.; Nimmo, J.R.

    2013-01-01

    The impact of preferential flow on recharge and contaminant transport poses a considerable challenge to water-resources management. Typical hydrologic models require extensive site characterization, but can underestimate fluxes when preferential flow is significant. A recently developed source-responsive model incorporates film-flow theory with conservation of mass to estimate unsaturated-zone preferential fluxes with readily available data. The term source-responsive describes the sensitivity of preferential flow in response to water availability at the source of input. We present the first rigorous tests of a parsimonious formulation for simulating water table fluctuations using two case studies, both in arid regions with thick unsaturated zones of fractured volcanic rock. Diffuse flow theory cannot adequately capture the observed water table responses at both sites; the source-responsive model is a viable alternative. We treat the active area fraction of preferential flow paths as a scaled function of water inputs at the land surface then calibrate the macropore density to fit observed water table rises. Unlike previous applications, we allow the characteristic film-flow velocity to vary, reflecting the lag time between source and deep water table responses. Analysis of model performance and parameter sensitivity for the two case studies underscores the importance of identifying thresholds for initiation of film flow in unsaturated rocks, and suggests that this parsimonious approach is potentially of great practical value.

  2. Use of Isotopic Techniques for the Assessment of Hydrological Interactions Between Ground and Surface Waters - Rio Man, Cienaga Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Palacio, P.; Dapena, C.; Betancur, T. [Universidad de Antioquia, Medellin (Colombia)

    2013-07-15

    The Man River basin is located in the lower foothills of the western and central ranges of the tropical Andes, Colombia. In this area hydrological studies and hydrochemical analyses were carried out and isotopic techniques applied to describe and understand the interactions between ground and surface waters. To expand this model and to include elements other than local hydrodynamics, relationships between regional precipitation, recharge, regional flow paths and hydraulic gradients controlling water flows from big rivers to groundwater are currently being explored. Accordingly, an isotope local meteoric water line was derived and it was discovered that the relationship between ground and surface waters is similar in wet and dry seasons. Precipitation constitutes the main recharge source, base flow is important in supporting flow in rivers, streams and wetlands, and evaporation causes effects over water systems in dry periods. A tendency towards increasing air temperatures has been detected in the Man River; this change may cause negative impacts over the hydrological system, affecting evapotranspiration- recharge processes. (author)

  3. Olkiluoto surface hydrological modelling: Update 2012 including salt transport modelling

    International Nuclear Information System (INIS)

    Karvonen, T.

    2013-11-01

    Posiva Oy is responsible for implementing a final disposal program for spent nuclear fuel of its owners Teollisuuden Voima Oyj and Fortum Power and Heat Oy. The spent nuclear fuel is planned to be disposed at a depth of about 400-450 meters in the crystalline bedrock at the Olkiluoto site. Leakages located at or close to spent fuel repository may give rise to the upconing of deep highly saline groundwater and this is a concern with regard to the performance of the tunnel backfill material after the closure of the tunnels. Therefore a salt transport sub-model was added to the Olkiluoto surface hydrological model (SHYD). The other improvements include update of the particle tracking algorithm and possibility to estimate the influence of open drillholes in a case where overpressure in inflatable packers decreases causing a hydraulic short-circuit between hydrogeological zones HZ19 and HZ20 along the drillhole. Four new hydrogeological zones HZ056, HZ146, BFZ100 and HZ039 were added to the model. In addition, zones HZ20A and HZ20B intersect with each other in the new structure model, which influences salinity upconing caused by leakages in shafts. The aim of the modelling of long-term influence of ONKALO, shafts and repository tunnels provide computational results that can be used to suggest limits for allowed leakages. The model input data included all the existing leakages into ONKALO (35-38 l/min) and shafts in the present day conditions. The influence of shafts was computed using eight different values for total shaft leakage: 5, 11, 20, 30, 40, 50, 60 and 70 l/min. The selection of the leakage criteria for shafts was influenced by the fact that upconing of saline water increases TDS-values close to the repository areas although HZ20B does not intersect any deposition tunnels. The total limit for all leakages was suggested to be 120 l/min. The limit for HZ20 zones was proposed to be 40 l/min: about 5 l/min the present day leakages to access tunnel, 25 l/min from

  4. Olkiluoto surface hydrological modelling: Update 2012 including salt transport modelling

    Energy Technology Data Exchange (ETDEWEB)

    Karvonen, T. [WaterHope, Helsinki (Finland)

    2013-11-15

    Posiva Oy is responsible for implementing a final disposal program for spent nuclear fuel of its owners Teollisuuden Voima Oyj and Fortum Power and Heat Oy. The spent nuclear fuel is planned to be disposed at a depth of about 400-450 meters in the crystalline bedrock at the Olkiluoto site. Leakages located at or close to spent fuel repository may give rise to the upconing of deep highly saline groundwater and this is a concern with regard to the performance of the tunnel backfill material after the closure of the tunnels. Therefore a salt transport sub-model was added to the Olkiluoto surface hydrological model (SHYD). The other improvements include update of the particle tracking algorithm and possibility to estimate the influence of open drillholes in a case where overpressure in inflatable packers decreases causing a hydraulic short-circuit between hydrogeological zones HZ19 and HZ20 along the drillhole. Four new hydrogeological zones HZ056, HZ146, BFZ100 and HZ039 were added to the model. In addition, zones HZ20A and HZ20B intersect with each other in the new structure model, which influences salinity upconing caused by leakages in shafts. The aim of the modelling of long-term influence of ONKALO, shafts and repository tunnels provide computational results that can be used to suggest limits for allowed leakages. The model input data included all the existing leakages into ONKALO (35-38 l/min) and shafts in the present day conditions. The influence of shafts was computed using eight different values for total shaft leakage: 5, 11, 20, 30, 40, 50, 60 and 70 l/min. The selection of the leakage criteria for shafts was influenced by the fact that upconing of saline water increases TDS-values close to the repository areas although HZ20B does not intersect any deposition tunnels. The total limit for all leakages was suggested to be 120 l/min. The limit for HZ20 zones was proposed to be 40 l/min: about 5 l/min the present day leakages to access tunnel, 25 l/min from

  5. Plot-scale field experiment of surface hydrologic processes with EOS implications

    Science.gov (United States)

    Laymon, Charles A.; Macari, Emir J.; Costes, Nicholas C.

    1992-01-01

    Plot-scale hydrologic field studies were initiated at NASA Marshall Space Flight Center to a) investigate the spatial and temporal variability of surface and subsurface hydrologic processes, particularly as affected by vegetation, and b) develop experimental techniques and associated instrumentation methodology to study hydrologic processes at increasingly large spatial scales. About 150 instruments, most of which are remotely operated, have been installed at the field site to monitor ground atmospheric conditions, precipitation, interception, soil-water status, and energy flux. This paper describes the nature of the field experiment, instrumentation and sampling rationale, and presents preliminary findings.

  6. Conceptual hydrologic model of flow in the unsaturated zone, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Montazer, P.; Wilson, W.E.

    1984-01-01

    The purpose of this report is to propose a conceptual hydrologic model that reasonably describes the flow of fluids through the unsaturated zone at Yucca Mountain, for use as a basis for preliminary site-performance assessment and as a guide to further investigations. Scott and others (1983) presented an initial conceptual hydrogeologic model for the unsaturated zone at Yucca Mountain, based on detailed geologic, but very limited hydrologic, information. In this report, some of their concepts are examined and either supported or modified, and new concepts are developed. The model describes the manner in which flow probably occurs at Yucca Mountain and is based on: (1) current understanding of the hydrogeologic framework; (2) application of the principles of unsaturated flow; and (3) interpretation of some preliminary data from ongoing field and laboratory investigations. Included are extensive geologic information but relatively few hydrologic data that currently exist from the unsaturated zone in the Yucca Mountain area. Many uncertainties remain to be resolved concerning hydrologic conditions and processes. As a result, most of the concepts presented are intentionally descriptive and conjectural, with little quantitative basis provided. However, for the sake of directness and simplicity of expression, the model is presented as if it were a true expression of the facts. The authors recognize, and the reader should be aware, that the proposed model probably is not the only reasonable description that could be made at this point, and it certainly is subject to revision and quantification as more data become available. Although various alternative models probably could be developed, the one described in this report seems to fit current understanding of the unsaturated flow through a section of layered, fractured-rock formations with contrasting hydrologic properties, such as occurs at Yucca Mountain. 41 refs., 14 figs., 1 tab

  7. Isotope-hydrological models and calculational methods for investigation of groundwater flow

    International Nuclear Information System (INIS)

    Marton, L.

    1982-01-01

    Recharge of groundwater through a semi-confining bed is a typical hydrogeological phenomenon in quaternary deposits which are elevated to a lesser or greater degree above the surroundings. A simple hydrological model has been introduced in which the aquifer is recharged only by precipitation through a semi-permeable layer. For applying the model, it is necessary to know the age of the water or the radioisotope concentrations in some sections of the ground-water flow system. On the basis of the age, the hydraulic conductivity of the aquifer and of the semiconfining bed and the steady rate of infiltration can be calculated. Other hydraulic parameters can be determined with the help of a mathemathical model worked out by Freeze and Witherspoon. The hydrological and mathemathical models are inversely used and are complementary. The reliability and applicability of the hydrological model has been proved in practice and good results were gained in hydrogeological research carried out in Hungary. (author)

  8. What will be the impacts of climate change on surface hydrology in France by 2070?

    International Nuclear Information System (INIS)

    Chauveau, Mathilde; Chazot, Sebastien; David, Julian; Norotte, Thomas; Perrin, Charles; Bourgin, Pierre-Yves; Sauquet, Eric; Vidal, Jean-Philippe; Rouchy, Nathalie; Martin, Eric; Maugis, Pascal; De Lacaze, Xavier

    2013-01-01

    Within the Explore 2070 project, an evaluation of the possible impacts of climate change on surface water between the 1961-1990 reference period and the 2046-2065 period was carried out in continental France and i n overseas departments on the basis of the A1B greenhouse gas emission scenario, seven general circulation models an d two hydrological models (Isba-Modcou and GR4J). In continental France, results indicate: (1) a possible increase in ai r temperature between +1.4 deg. C and +3 deg. C; (2) an uncertain evolution of precipitation, most models however agreeing on a decreasing trend in summer precipitation; (3) a significant decrease (10% to 40%) of mean annual flows at the country scale, especially pronounced in the Seine-Normandie and Adour-Garonne districts; (4) a strong decrease in summer lo w flows in most basins; (5) more heterogeneous and less significant evolutions for floods. A special care was given to the quantification of the uncertainties linked to these results. They provide an indication of the significance of projected changes. The evolutions calculated in the overseas zones can be considered non-significant given the level of uncertainty linked to the hydro-climatic modelling chain. These results urge to implement adaptation strategies based on a better management of water resources, among others. (authors)

  9. The possible influence of terracettes on surface hydrology of steep-sloping and subalpine environments

    Science.gov (United States)

    Greenwood, Philip; Kuonen, Samuel; Fister, Wolfgang; Kuhn, Nikolaus

    2015-04-01

    Alpine and mountain slopes represent important pathways that link high altitude grazing areas to meadows and rangelands at lower elevations. Given the often acute gradients associated with such environments, they potentially represent highly efficient runoff conveyance routes that presumably facilitate the downslope movement of runoff and associated material during erosion events. Many such slopes host series of small steps, or `terracettes`. The position of terracette systems, usually juxtaposed across the natural downslope flow-path of acute slopes, lead us to hypothesise that their presence may influence typical hillslope processes by intercepting or capturing surface runoff during its downslope transit. Here we report preliminary results and some tentative conclusions from on-going work to explore this possibility. Google Earth was used to initially identify a ca. 400 m2 area of well-developed terracette system situated on a west-facing slope with gradients ranging from 25-40o (46-84%). A digital elevation model (DEM) of a section of the terracette system was constructed using spatial data taken from a relevant excerpt of a topographic map. The DEM was then queried using a flow accumulation algorithm and the results were displayed in a Geographic Information System (GIS). The output data provided 'proof of concept' that terracettes are able to capture surface runoff. A series of rainfall / runoff simulations was then performed on the same section of terracettes. Results from both components of the investigation indicate that certain sections of a terracette system intercepted surface runoff and acted as preferential flow-pathways during runoff events. By contrast, and despite being subjected to intense rainfall, some sections of the same terracette system did not generate surface runoff. Based on these contrasting findings, we cautiously predict that areas where surface runoff was not generated may actually act as depositional sites, or retention zones, and

  10. Surface Runoff in Watershed Modeling—Turbulent or Laminar Flows?

    Directory of Open Access Journals (Sweden)

    Mark E. Grismer

    2016-05-01

    Full Text Available Determination of overland sheet flow depths, velocities and celerities across the hillslope in watershed modeling is important towards estimation of surface storage, travel times to streams and soil detachment rates. It requires careful characterization of the flow processes. Similarly, determination of the temporal variation of hillslope-riparian-stream hydrologic connectivity requires estimation of the shallow subsurface soil hydraulic conductivity and soil-water retention (i.e., drainable porosities parameters. Field rainfall and runoff simulation studies provide considerable information and insight into these processes; in particular, that sheet flows are likely laminar and that shallow hydraulic conductivities and storage can be determined from the plot studies. Here, using a 1 m by 2 m long runoff simulation flume, we found that for overland flow rates per unit width of roughly 30–60 mm2/s and bedslopes of 10%–66% with varying sand roughness depths that all flow depths were predicted by laminar flow equations alone and that equivalent Manning’s n values were depth dependent and quite small relative to those used in watershed modeling studies. Even for overland flow rates greater than those typically measured or modeled and using Manning’s n values of 0.30–0.35, often assumed in physical watershed model applications for relatively smooth surface conditions, the laminar flow velocities were 4–5 times greater, while the laminar flow depths were 4–5 times smaller. This observation suggests that travel times, surface storage volumes and surface shear stresses associated with erosion across the landscape would be poorly predicted using turbulent flow assumptions. Filling the flume with fine sand and conducting runoff studies, we were unable to produce sheet flow, but found that subsurface flows were onflow rate, soil depth and slope dependent and drainable porosities were only soil depth and slope dependent. Moreover, both the sand

  11. Quantifying watershed surface depression storage: determination and application in a hydrologic model

    Science.gov (United States)

    Joseph K. O. Amoah; Devendra M. Amatya; Soronnadi. Nnaji

    2012-01-01

    Hydrologic models often require correct estimates of surface macro-depressional storage to accurately simulate rainfall–runoff processes. Traditionally, depression storage is determined through model calibration or lumped with soil storage components or on an ad hoc basis. This paper investigates a holistic approach for estimating surface depressional storage capacity...

  12. Validating alternative methodologies to estimate the hydrological regime of temporary streams when flow data are unavailable

    Science.gov (United States)

    Llorens, Pilar; Gallart, Francesc; Latron, Jérôme; Cid, Núria; Rieradevall, Maria; Prat, Narcís

    2016-04-01

    Aquatic life in temporary streams is strongly conditioned by the temporal variability of the hydrological conditions that control the occurrence and connectivity of diverse mesohabitats. In this context, the software TREHS (Temporary Rivers' Ecological and Hydrological Status) has been developed, in the framework of the LIFE Trivers project, to help managers for adequately implement the Water Framework Directive in this type of water bodies. TREHS, using the methodology described in Gallart et al (2012), defines six temporal 'aquatic states', based on the hydrological conditions representing different mesohabitats, for a given reach at a particular moment. Nevertheless, hydrological data for assessing the regime of temporary streams are often non-existent or scarce. The scarcity of flow data makes frequently impossible the characterization of temporary streams hydrological regimes and, as a consequence, the selection of the correct periods and methods to determine their ecological status. Because of its qualitative nature, the TREHS approach allows the use of alternative methodologies to assess the regime of temporary streams in the lack of observed flow data. However, to adapt the TREHS to this qualitative data both the temporal scheme (from monthly to seasonal) as well as the number of aquatic states (from 6 to 3) have been modified. Two alternatives complementary methodologies were tested within the TREHS framework to assess the regime of temporary streams: interviews and aerial photographs. All the gauging stations (13) belonging to the Catalan Internal Catchments (NE, Spain) with recurrent zero flows periods were selected to validate both methodologies. On one hand, non-structured interviews were carried out to inhabitants of villages and small towns near the gauging stations. Flow permanence metrics for input into TREHS were drawn from the notes taken during the interviews. On the other hand, the historical series of available aerial photographs (typically 10

  13. Description of climate, surface hydrology, and near-surface hydrogeology. Preliminary site description. Forsmark area - version 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Per-Olof [Artesia Grundvattenkonsult AB, Stockholm (Sweden); Werner, Kent [SWECO VIAK AB/Golder Associates AB, Stockholm (Sweden); Bosson, Emma; Berglund, Sten [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Juston, John [DBE Sweden, Uppsala (Sweden)

    2005-06-15

    The Swedish Nuclear Fuel and Waste Management Company (SKB) is conducting site investigations at two different locations, the Forsmark and Simpevarp areas, with the objective of siting a geological repository for spent nuclear fuel. The results from the investigations at the sites are used as a basic input to the development of Site Descriptive Models (SDM). The SDM shall summarise the current state of knowledge of the site, and provide parameters and models to be used in further analyses within Safety Assessment, Repository Design and Environmental Impact Assessment. The present report is a background report describing the meteorological conditions and the modelling of surface hydrology and near-surface hydrogeology in support of the Forsmark version 1.2 SDM based on the data available in the Forsmark 1.2 'data freeze' (July 31, 2004). The groundwater is very shallow, with groundwater levels within one meter below ground as an annual mean for almost all groundwater monitoring wells. Also, the annual groundwater level amplitude is less than 1.5 m for most wells. The shallow groundwater levels mean that there is a strong interaction between evapotranspiration, soil moisture and groundwater. In the modelling, surface water and near-surface groundwater divides are assumed to coincide. The small-scale topography implies that many local, shallow groundwater flow systems are formed in the Quaternary deposits, overlaying more large-scale flow systems associated with groundwater flows at greater depths. Groundwater level time series from wells in till and bedrock within the same areas show a considerably higher groundwater level in the till than in the bedrock. The observed differences in levels are not fully consistent with the good hydraulic contact between overburden and bedrock indicated by the hydraulic tests in the Quaternary deposits. However, the relatively lower groundwater levels in the bedrock may be caused by the horizontal to sub-horizontal highly

  14. Description of climate, surface hydrology, and near-surface hydrogeology. Preliminary site description. Forsmark area - version 1.2

    International Nuclear Information System (INIS)

    Johansson, Per-Olof; Werner, Kent; Bosson, Emma; Berglund, Sten; Juston, John

    2005-06-01

    The present report is a background report describing the meteorological conditions and the modelling of surface hydrology and near-surface hydrogeology in support of the Forsmark version 1.2 SDM based on the data available in the Forsmark 1.2 ''data freeze'' (July 31, 2004). The area covered in the conceptual and descriptive modelling is characterised by a low relief and a small-scale topography. Almost the whole area is located below 20 m a s l (metres above sea level). The corrected mean annual precipitation is 600-650 mm and the mean annual evapotranspiration can be estimated to a little more than 400 mm, leaving approximately 200 mm x year-1 for runoff. Till is the dominating Quaternary deposit covering approximately 75% of the area. In most of the area, the till is sandy. Bedrock outcrops are frequent but cover only approximately 5% of the area. Direct groundwater recharge from precipitation is the dominant source of groundwater recharge. The small-scale topography implies that many local, shallow groundwater flow systems are formed in the Quaternary deposits, overlaying more large-scale flow systems associated with groundwater flows at greater depths. Groundwater level time series from wells in till and bedrock within the same areas show a considerably higher groundwater level in the till than in the bedrock. The sediment stratigraphy of lakes and wetlands is crucial for their function as discharge areas for groundwater. Comparisons between measured lake water levels and groundwater levels below and around lakes indicate that the lakes in some cases may act as sources of groundwater recharge. Specifically, observations from Lake Bolundsfjaerden and Lake Eckarfjaerden show that such conditions were at hand during the dry summer of 2003. However, whether the observed water level relations correspond to significant water fluxes depends also on the hydrogeological properties of the lake sediments and the underlying Quaternary deposits. ''Old'' water with high

  15. Land surface modelling in hydrology and meteorology – lessons learned from the Baltic Basin

    Directory of Open Access Journals (Sweden)

    L. P. Graham

    2000-01-01

    Full Text Available By both tradition and purpose, the land parameterization schemes of hydrological and meteorological models differ greatly. Meteorologists are concerned primarily with solving the energy balance, whereas hydrologists are most interested in the water balance. Meteorological climate models typically have multi-layered soil parameterisation that solves temperature fluxes numerically with diffusive equations. The same approach is carried over to a similar treatment of water transport. Hydrological models are not usually so interested in soil temperatures, but must provide a reasonable representation of soil moisture to get runoff right. To treat the heterogeneity of the soil, many hydrological models use only one layer with a statistical representation of soil variability. Such a hydrological model can be used on large scales while taking subgrid variability into account. Hydrological models also include lateral transport of water – an imperative if' river discharge is to be estimated. The concept of a complexity chain for coupled modelling systems is introduced, together with considerations for mixing model components. Under BALTEX (Baltic Sea Experiment and SWECLIM (Swedish Regional Climate Modelling Programme, a large-scale hydrological model of runoff in the Baltic Basin is used to review atmospheric climate model simulations. This incorporates both the runoff record and hydrological modelling experience into atmospheric model development. Results from two models are shown. A conclusion is that the key to improved models may be less complexity. Perhaps the meteorological models should keep their multi-layered approach for modelling soil temperature, but add a simpler, yet physically consistent, hydrological approach for modelling snow processes and water transport in the soil. Keywords: land surface modelling; hydrological modelling; atmospheric climate models; subgrid variability; Baltic Basin

  16. Radionuclide transfer onto ground surface in surface water flow, 1

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu; Kamiyama, Hideo

    1991-07-01

    Radionuclides migration in ground surface water flow is considered to be one of the important path way in the scenario for environmental migration of radionuclides leaked from low level radioactive waste repository. Simulating the slightly sloped surface on which contaminated solution is flowing downward, testing for radionuclide migration on ground surface had been started. As it's first step, an experiment was carried out under the condition of restricted infiltration in order to elucidate the adsorption behavior of radionuclides onto the loamy soil surface in related with hydraulic conditions. Radionuclides concentration change in effluent solution with time and a concentration distribution of radionuclides adsorbed on the ground surface were obtained from several experimental conditions combining the rate and the duration time of the water flow. The radionuclides concentration in the effluent solution was nearly constant during each experimental period, and was reduced under the condition of lower flow rate. The surface distribution of radionuclides concentration showed two distinctive regions. The one was near the inlet vessel where the concentration was promptly reducing, and the other was following the former where the concentration was nearly constant. The characteristic surface distribution of radionuclides concentration can be explained by a two dimensional diffusion model with a first order adsorption reaction, based on the advection of flow rate distribution in perpendicular direction. (author)

  17. Modelling food-web mediated effects of hydrological variability and environmental flows.

    Science.gov (United States)

    Robson, Barbara J; Lester, Rebecca E; Baldwin, Darren S; Bond, Nicholas R; Drouart, Romain; Rolls, Robert J; Ryder, Darren S; Thompson, Ross M

    2017-11-01

    Environmental flows are designed to enhance aquatic ecosystems through a variety of mechanisms; however, to date most attention has been paid to the effects on habitat quality and life-history triggers, especially for fish and vegetation. The effects of environmental flows on food webs have so far received little attention, despite food-web thinking being fundamental to understanding of river ecosystems. Understanding environmental flows in a food-web context can help scientists and policy-makers better understand and manage outcomes of flow alteration and restoration. In this paper, we consider mechanisms by which flow variability can influence and alter food webs, and place these within a conceptual and numerical modelling framework. We also review the strengths and weaknesses of various approaches to modelling the effects of hydrological management on food webs. Although classic bioenergetic models such as Ecopath with Ecosim capture many of the key features required, other approaches, such as biogeochemical ecosystem modelling, end-to-end modelling, population dynamic models, individual-based models, graph theory models, and stock assessment models are also relevant. In many cases, a combination of approaches will be useful. We identify current challenges and new directions in modelling food-web responses to hydrological variability and environmental flow management. These include better integration of food-web and hydraulic models, taking physiologically-based approaches to food quality effects, and better representation of variations in space and time that may create ecosystem control points. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  18. Free surface flows: coalescence, spreading and dewetting

    NARCIS (Netherlands)

    Hernandez Sanchez, J.F.

    2015-01-01

    Capillary and wetting phenomena are an essential part of nature. Its presence is noticed in many circumstances where solid and liquid surfaces come into contact. In this thesis different types of capillary free surface flows are studied. The topics discussed are mainly the coalescence of viscous

  19. Hydrological regime shift in a constructed catchment: Effect of vegetation encroachment on surface runoff

    Science.gov (United States)

    Hinz, C.; Caviedes-Voullieme, D.; Andezhath Mohanan, A.; Brueck, Y.; Zaplata, M.

    2017-12-01

    The Hühnerwasser catchment (Chicken Creek) was constructed to provide discharge for a small stream in the post-mining landscape of Lusatia, Germany. It has an area of 6 ha and quaternary sands with a thickness of 2-4 m were dumped on to a clay liner to prevent deep drainage. After completion of the construction the catchment was left to develop on its own without intervention and has been monitored since 2005. The upper part of the catchment discharges water and sediment into the lower part forming an alluvial fan. Below the alluvial fan is a pond receiving all surface and subsurface water from the upper catchment. After the formation of the drainage network vegetation started growing and surface runoff decreased until the water balance was dominated by evapotranspiration. This regime shift and the rate at which it happened depends on the vegetation encroachment into the rills and the interrill areas. Based on the hypothesis that vegetation will increase surface roughness and infiltration behavior, aerial photos were used to map rills and vegetation within and outside the rills for the last 10 years to obtain a time series of change. Observational evidence clearly shows that vegetation encroaches from the bottom, from the interrill areas as well as from the top. The rills themselves did not change their topology, however, the width of the erosion rills and gully increased at the bottom. For a subcatchment area a high resolution a physical based numerical model of overland flow was developed to explicitly assess the importance of increasing roughness and infiltration capacity for surface runoff. For the purpose of analyzing the effect of rainfall variability a rainfall generator was developed to carry out large sets of simulations. The simulations provide a means to assess how the roughness/infiltration feedback affects the rate of regime shift for a set of parameters that are consistent with the observed hydrological behavior of the drainage network.

  20. Hydrologic response to multimodel climate output using a physically based model of groundwater/surface water interactions

    Science.gov (United States)

    Sulis, M.; Paniconi, C.; Marrocu, M.; Huard, D.; Chaumont, D.

    2012-12-01

    General circulation models (GCMs) are the primary instruments for obtaining projections of future global climate change. Outputs from GCMs, aided by dynamical and/or statistical downscaling techniques, have long been used to simulate changes in regional climate systems over wide spatiotemporal scales. Numerous studies have acknowledged the disagreements between the various GCMs and between the different downscaling methods designed to compensate for the mismatch between climate model output and the spatial scale at which hydrological models are applied. Very little is known, however, about the importance of these differences once they have been input or assimilated by a nonlinear hydrological model. This issue is investigated here at the catchment scale using a process-based model of integrated surface and subsurface hydrologic response driven by outputs from 12 members of a multimodel climate ensemble. The data set consists of daily values of precipitation and min/max temperatures obtained by combining four regional climate models and five GCMs. The regional scenarios were downscaled using a quantile scaling bias-correction technique. The hydrologic response was simulated for the 690 km2des Anglais catchment in southwestern Quebec, Canada. The results show that different hydrological components (river discharge, aquifer recharge, and soil moisture storage) respond differently to precipitation and temperature anomalies in the multimodel climate output, with greater variability for annual discharge compared to recharge and soil moisture storage. We also find that runoff generation and extreme event-driven peak hydrograph flows are highly sensitive to any uncertainty in climate data. Finally, the results show the significant impact of changing sequences of rainy days on groundwater recharge fluxes and the influence of longer dry spells in modifying soil moisture spatial variability.

  1. Effects of plough pan development on surface hydrology and on soil physical properties in Southeastern Brazilian plateau

    Science.gov (United States)

    Bertolino, Ana V. F. A.; Fernandes, Nelson F.; Miranda, João P. L.; Souza, Andréa P.; Lopes, Marcel R. S.; Palmieri, Francesco

    2010-10-01

    SummaryConventional tillage may impose changes in soil physical properties that lead to a decrease in soil physical quality. Although plough pan formation is considered to be an important consequence of conventional tillage practices in Southeastern Brazil, few studies have focused on its hydrological consequences. Detailed investigations in two experimental plots located in the hilly landscape of Serra do Mar close to Rio de Janeiro city were carried out to characterize the changes in soil physical properties and in soil hydrology due to plough pan formation. Conventional (CT) and minimum tillage (MT) practices were implemented in two plots for 3 years and soil matric potential (SMP) was monitored in each plot via nests of tensiometers and Watermark® sensors installed at different depths. Undisturbed soil blocks were collected for micromorphological analyses to quantify the total pore space in soils under CT and MT systems, and in soils under natural tropical forest. Results suggest that soils under the CT system developed a plough pan layer at about 20 cm depth that had 44% less total porosity as compared to surface conditions. It is shown that soils under the CT system tended to stay saturated for longer periods of time after each rainfall event. Besides, during intense rainy periods soils under the CT system may develop hydrologic conditions that favor lateral flows while soils under the MT system were still draining. Such hydrological responses may explain why average soil erosion rates measured for individual rainfall events under the CT system were about 2.5 times greater than the ones observed at MT. The results attested that conventional tillage in this area generated modifications in soil fabric, especially in pore-size distribution and connectivity, which induced important changes in soil hydrology and soil erosion. The agricultural practices used in this area, associated with the local steep hillslopes and intense rainfall events, are definitely not

  2. Predicting the natural flow regime: Models for assessing hydrological alteration in streams

    Science.gov (United States)

    Carlisle, D.M.; Falcone, J.; Wolock, D.M.; Meador, M.R.; Norris, R.H.

    2009-01-01

    Understanding the extent to which natural streamflow characteristics have been altered is an important consideration for ecological assessments of streams. Assessing hydrologic condition requires that we quantify the attributes of the flow regime that would be expected in the absence of anthropogenic modifications. The objective of this study was to evaluate whether selected streamflow characteristics could be predicted at regional and national scales using geospatial data. Long-term, gaged river basins distributed throughout the contiguous US that had streamflow characteristics representing least disturbed or near pristine conditions were identified. Thirteen metrics of the magnitude, frequency, duration, timing and rate of change of streamflow were calculated using a 20-50 year period of record for each site. We used random forests (RF), a robust statistical modelling approach, to develop models that predicted the value for each streamflow metric using natural watershed characteristics. We compared the performance (i.e. bias and precision) of national- and regional-scale predictive models to that of models based on landscape classifications, including major river basins, ecoregions and hydrologic landscape regions (HLR). For all hydrologic metrics, landscape stratification models produced estimates that were less biased and more precise than a null model that accounted for no natural variability. Predictive models at the national and regional scale performed equally well, and substantially improved predictions of all hydrologic metrics relative to landscape stratification models. Prediction error rates ranged from 15 to 40%, but were 25% for most metrics. We selected three gaged, non-reference sites to illustrate how predictive models could be used to assess hydrologic condition. These examples show how the models accurately estimate predisturbance conditions and are sensitive to changes in streamflow variability associated with long-term land-use change. We also

  3. Review of Constructed Subsurface Flow vs. Surface Flow Wetlands

    International Nuclear Information System (INIS)

    HALVERSON, NANCY

    2004-01-01

    The purpose of this document is to use existing documentation to review the effectiveness of subsurface flow and surface flow constructed wetlands in treating wastewater and to demonstrate the viability of treating effluent from Savannah River Site outfalls H-02 and H-04 with a subsurface flow constructed wetland to lower copper, lead and zinc concentrations to within National Pollutant Discharge Elimination System (NPDES) Permit limits. Constructed treatment wetlands are engineered systems that have been designed and constructed to use the natural functions of wetlands for wastewater treatment. Constructed wetlands have significantly lower total lifetime costs and often lower capital costs than conventional treatment systems. The two main types of constructed wetlands are surface flow and subsurface flow. In surface flow constructed wetlands, water flows above ground. Subsurface flow constructed wetlands are designed to keep the water level below the top of the rock or gravel media, thus minimizing human and ecological exposure. Subsurface flow wetlands demonstrate higher rates of contaminant removal per unit of land than surface flow (free water surface) wetlands, therefore subsurface flow wetlands can be smaller while achieving the same level of contaminant removal. Wetlands remove metals using a variety of processes including filtration of solids, sorption onto organic matter, oxidation and hydrolysis, formation of carbonates, formation of insoluble sulfides, binding to iron and manganese oxides, reduction to immobile forms by bacterial activity, and uptake by plants and bacteria. Metal removal rates in both subsurface flow and surface flow wetlands can be high, but can vary greatly depending upon the influent concentrations and the mass loading rate. Removal rates of greater than 90 per cent for copper, lead and zinc have been demonstrated in operating surface flow and subsurface flow wetlands. The constituents that exceed NPDES limits at outfalls H-02 a nd H

  4. Modeling large-scale human alteration of land surface hydrology and climate

    Science.gov (United States)

    Pokhrel, Yadu N.; Felfelani, Farshid; Shin, Sanghoon; Yamada, Tomohito J.; Satoh, Yusuke

    2017-12-01

    Rapidly expanding human activities have profoundly affected various biophysical and biogeochemical processes of the Earth system over a broad range of scales, and freshwater systems are now amongst the most extensively altered ecosystems. In this study, we examine the human-induced changes in land surface water and energy balances and the associated climate impacts using a coupled hydrological-climate model framework which also simulates the impacts of human activities on the water cycle. We present three sets of analyses using the results from two model versions—one with and the other without considering human activities; both versions are run in offline and coupled mode resulting in a series of four experiments in total. First, we examine climate and human-induced changes in regional water balance focusing on the widely debated issue of the desiccation of the Aral Sea in central Asia. Then, we discuss the changes in surface temperature as a result of changes in land surface energy balance due to irrigation over global and regional scales. Finally, we examine the global and regional climate impacts of increased atmospheric water vapor content due to irrigation. Results indicate that the direct anthropogenic alteration of river flow in the Aral Sea basin resulted in the loss of 510 km3 of water during the latter half of the twentieth century which explains about half of the total loss of water from the sea. Results of irrigation-induced changes in surface energy balance suggest a significant surface cooling of up to 3.3 K over 1° grids in highly irrigated areas but a negligible change in land surface temperature when averaged over sufficiently large global regions. Results from the coupled model indicate a substantial change in 2 m air temperature and outgoing longwave radiation due to irrigation, highlighting the non-local (regional and global) implications of irrigation. These results provide important insights on the direct human alteration of land surface

  5. 2-way coupling the hydrological land surface model PROMET with the regional climate model MM5

    Directory of Open Access Journals (Sweden)

    F. Zabel

    2013-05-01

    Full Text Available Most land surface hydrological models (LSHMs consider land surface processes (e.g. soil–plant–atmosphere interactions, lateral water flows, snow and ice in a spatially detailed manner. The atmosphere is considered as exogenous driver, neglecting feedbacks between the land surface and the atmosphere. On the other hand, regional climate models (RCMs generally simulate land surface processes through coarse descriptions and spatial scales but include land–atmosphere interactions. What is the impact of the differently applied model physics and spatial resolution of LSHMs on the performance of RCMs? What feedback effects are induced by different land surface models? This study analyses the impact of replacing the land surface module (LSM within an RCM with a high resolution LSHM. A 2-way coupling approach was applied using the LSHM PROMET (1 × 1 km2 and the atmospheric part of the RCM MM5 (45 × 45 km2. The scaling interface SCALMET is used for down- and upscaling the linear and non-linear fluxes between the model scales. The change in the atmospheric response by MM5 using the LSHM is analysed, and its quality is compared to observations of temperature and precipitation for a 4 yr period from 1996 to 1999 for the Upper Danube catchment. By substituting the Noah-LSM with PROMET, simulated non-bias-corrected near-surface air temperature improves for annual, monthly and daily courses when compared to measurements from 277 meteorological weather stations within the Upper Danube catchment. The mean annual bias was improved from −0.85 to −0.13 K. In particular, the improved afternoon heating from May to September is caused by increased sensible heat flux and decreased latent heat flux as well as more incoming solar radiation in the fully coupled PROMET/MM5 in comparison to the NOAH/MM5 simulation. Triggered by the LSM replacement, precipitation overall is reduced; however simulated precipitation amounts are still of high uncertainty, both

  6. Chance-constrained overland flow modeling for improving conceptual distributed hydrologic simulations based on scaling representation of sub-daily rainfall variability

    International Nuclear Information System (INIS)

    Han, Jing-Cheng; Huang, Guohe; Huang, Yuefei; Zhang, Hua; Li, Zhong; Chen, Qiuwen

    2015-01-01

    Lack of hydrologic process representation at the short time-scale would lead to inadequate simulations in distributed hydrological modeling. Especially for complex mountainous watersheds, surface runoff simulations are significantly affected by the overland flow generation, which is closely related to the rainfall characteristics at a sub-time step. In this paper, the sub-daily variability of rainfall intensity was considered using a probability distribution, and a chance-constrained overland flow modeling approach was proposed to capture the generation of overland flow within conceptual distributed hydrologic simulations. The integrated modeling procedures were further demonstrated through a watershed of China Three Gorges Reservoir area, leading to an improved SLURP-TGR hydrologic model based on SLURP. Combined with rainfall thresholds determined to distinguish various magnitudes of daily rainfall totals, three levels of significance were simultaneously employed to examine the hydrologic-response simulation. Results showed that SLURP-TGR could enhance the model performance, and the deviation of runoff simulations was effectively controlled. However, rainfall thresholds were so crucial for reflecting the scaling effect of rainfall intensity that optimal levels of significance and rainfall threshold were 0.05 and 10 mm, respectively. As for the Xiangxi River watershed, the main runoff contribution came from interflow of the fast store. Although slight differences of overland flow simulations between SLURP and SLURP-TGR were derived, SLURP-TGR was found to help improve the simulation of peak flows, and would improve the overall modeling efficiency through adjusting runoff component simulations. Consequently, the developed modeling approach favors efficient representation of hydrological processes and would be expected to have a potential for wide applications. - Highlights: • We develop an improved hydrologic model considering the scaling effect of rainfall. • A

  7. Chance-constrained overland flow modeling for improving conceptual distributed hydrologic simulations based on scaling representation of sub-daily rainfall variability

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jing-Cheng [State Key Laboratory of Hydroscience & Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084 (China); Huang, Guohe, E-mail: huang@iseis.org [Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina, Saskatchewan S4S 0A2 (Canada); Huang, Yuefei [State Key Laboratory of Hydroscience & Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084 (China); Zhang, Hua [College of Science and Engineering, Texas A& M University — Corpus Christi, Corpus Christi, TX 78412-5797 (United States); Li, Zhong [Institute for Energy, Environment and Sustainable Communities, University of Regina, Regina, Saskatchewan S4S 0A2 (Canada); Chen, Qiuwen [Center for Eco-Environmental Research, Nanjing Hydraulics Research Institute, Nanjing 210029 (China)

    2015-08-15

    Lack of hydrologic process representation at the short time-scale would lead to inadequate simulations in distributed hydrological modeling. Especially for complex mountainous watersheds, surface runoff simulations are significantly affected by the overland flow generation, which is closely related to the rainfall characteristics at a sub-time step. In this paper, the sub-daily variability of rainfall intensity was considered using a probability distribution, and a chance-constrained overland flow modeling approach was proposed to capture the generation of overland flow within conceptual distributed hydrologic simulations. The integrated modeling procedures were further demonstrated through a watershed of China Three Gorges Reservoir area, leading to an improved SLURP-TGR hydrologic model based on SLURP. Combined with rainfall thresholds determined to distinguish various magnitudes of daily rainfall totals, three levels of significance were simultaneously employed to examine the hydrologic-response simulation. Results showed that SLURP-TGR could enhance the model performance, and the deviation of runoff simulations was effectively controlled. However, rainfall thresholds were so crucial for reflecting the scaling effect of rainfall intensity that optimal levels of significance and rainfall threshold were 0.05 and 10 mm, respectively. As for the Xiangxi River watershed, the main runoff contribution came from interflow of the fast store. Although slight differences of overland flow simulations between SLURP and SLURP-TGR were derived, SLURP-TGR was found to help improve the simulation of peak flows, and would improve the overall modeling efficiency through adjusting runoff component simulations. Consequently, the developed modeling approach favors efficient representation of hydrological processes and would be expected to have a potential for wide applications. - Highlights: • We develop an improved hydrologic model considering the scaling effect of rainfall. • A

  8. Surface runoff in flat terrain: How field topography and runoff generating processes control hydrological connectivity

    NARCIS (Netherlands)

    Appels, W.M.; Bogaart, P.W.; Bogaart, P.W.; Zee, van der S.E.A.T.M.

    2016-01-01

    In flat lowland agricultural catchments in temperate climate zones with highly permeable sandy soils, surface runoff is a rare process with a large impact on the redistribution of sediments and solutes and stream water quality. We examine hydrological data obtained on two field sites in the

  9. Polygon formation and surface flow on a rotating fluid surface

    DEFF Research Database (Denmark)

    Bergmann, Raymond; Tophøj, Laust Emil Hjerrild; Homan, T. A. M.

    2011-01-01

    We present a study of polygons forming on the free surface of a water flow confined to a stationary cylinder and driven by a rotating bottom plate as described by Jansson et al. (Phys. Rev. Lett., vol. 96, 2006, 174502). In particular, we study the case of a triangular structure, either completely...... there the symmetry breaking proceeds like a low-dimensional linear instability. We show that the circular state and the unstable manifold connecting it with the polygon solution are universal in the sense that very different initial conditions lead to the same circular state and unstable manifold. For a wet triangle......, we measure the surface flows by particle image velocimetry (PIV) and show that there are three vortices present, but that the strength of these vortices is far too weak to account for the rotation velocity of the polygon. We show that partial blocking of the surface flow destroys the polygons and re...

  10. A flexible hydrological warning system in Denmark for real-time surface water and groundwater simulations

    Science.gov (United States)

    He, Xin; Stisen, Simon; Wiese, Marianne B.; Jørgen Henriksen, Hans

    2015-04-01

    In Denmark, increasing focus on extreme weather events has created considerable demand for short term forecasts and early warnings in relation to groundwater and surface water flooding. The Geological Survey of Denmark and Greenland (GEUS) has setup, calibrated and applied a nationwide water resources model, the DK-Model, primarily for simulating groundwater and surface water flows and groundwater levels during the past 20 years. So far, the DK-model has only been used in offline historical and future scenario simulations. Therefore, challenges arise in operating such a model for online forecasts and early warnings, which requires access to continuously updated observed climate input data and forecast data of precipitation, temperature and global radiation for the next 48 hours or longer. GEUS has a close collaboration with the Danish Meteorological Institute in order to test and enable this data input for the DK model. Due to the comprehensive physical descriptions of the DK-Model, the simulation results can potentially be any component of the hydrological cycle within the models domain. Therefore, it is important to identify which results need to be updated and saved in the real-time mode, since it is not computationally economical to save every result considering the heavy load of data. GEUS have worked closely with the end-users and interest groups such as water planners and emergency managers from the municipalities, water supply and waste water companies, consulting companies and farmer organizations, in order to understand their possible needs for real time simulation and monitoring of the nationwide water cycle. This participatory process has been supported by a web based questionnaire survey, and a workshop that connected the model developers and the users. For qualifying the stakeholder engagement, GEUS has selected a representative catchment area (Skjern River) for testing and demonstrating a prototype of the web based hydrological warning system at the

  11. Enhancing Global Land Surface Hydrology Estimates from the NASA MERRA Reanalysis Using Precipitation Observations and Model Parameter Adjustments

    Science.gov (United States)

    Reichle, Rolf; Koster, Randal; DeLannoy, Gabrielle; Forman, Barton; Liu, Qing; Mahanama, Sarith; Toure, Ally

    2011-01-01

    The Modern-Era Retrospective analysis for Research and Applications (MERRA) is a state-of-the-art reanalysis that provides. in addition to atmospheric fields. global estimates of soil moisture, latent heat flux. snow. and runoff for J 979-present. This study introduces a supplemental and improved set of land surface hydrological fields ('MERRA-Land') generated by replaying a revised version of the land component of the MERRA system. Specifically. the MERRA-Land estimates benefit from corrections to the precipitation forcing with the Global Precipitation Climatology Project pentad product (version 2.1) and from revised parameters in the rainfall interception model, changes that effectively correct for known limitations in the MERRA land surface meteorological forcings. The skill (defined as the correlation coefficient of the anomaly time series) in land surface hydrological fields from MERRA and MERRA-Land is assessed here against observations and compared to the skill of the state-of-the-art ERA-Interim reanalysis. MERRA-Land and ERA-Interim root zone soil moisture skills (against in situ observations at 85 US stations) are comparable and significantly greater than that of MERRA. Throughout the northern hemisphere, MERRA and MERRA-Land agree reasonably well with in situ snow depth measurements (from 583 stations) and with snow water equivalent from an independent analysis. Runoff skill (against naturalized stream flow observations from 15 basins in the western US) of MERRA and MERRA-Land is typically higher than that of ERA-Interim. With a few exceptions. the MERRA-Land data appear more accurate than the original MERRA estimates and are thus recommended for those interested in using '\\-tERRA output for land surface hydrological studies.

  12. Hydrologic and biogeochemical controls of river subsurface solutes under agriculturally enhanced ground water flow

    Science.gov (United States)

    Wildman, R.A.; Domagalski, Joseph L.; Hering, J.G.

    2009-01-01

    The relative influences of hydrologic processes and biogeochemistry on the transport and retention of minor solutes were compared in the riverbed of the lower Merced River (California, USA). The subsurface of this reach receives ground water discharge and surface water infiltration due to an altered hydraulic setting resulting from agricultural irrigation. Filtered ground water samples were collected from 30 drive point locations in March, June, and October 2004. Hydrologic processes, described previously, were verified by observations of bromine concentrations; manganese was used to indicate redox conditions. The separate responses of the minor solutes strontium, barium, uranium, and phosphorus to these influences were examined. Correlation and principal component analyses indicate that hydrologic processes dominate the distribution of trace elements in the ground water. Redox conditions appear to be independent of hydrologic processes and account for most of the remaining data variability. With some variability, major processes are consistent in two sampling transects separated by 100 m. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  13. Recession-based hydrological models for estimating low flows in ungauged catchments in the Himalayas

    Directory of Open Access Journals (Sweden)

    H. G. Rees

    2004-01-01

    Full Text Available The Himalayan region of Nepal and northern India experiences hydrological extremes from monsoonal floods during July to September, when most of the annual precipitation falls, to periods of very low flows during the dry season (December to February. While the monsoon floods cause acute disasters such as loss of human life and property, mudslides and infrastructure damage, the lack of water during the dry season has a chronic impact on the lives of local people. The management of water resources in the region is hampered by relatively sparse hydrometerological networks and consequently, many resource assessments are required in catchments where no measurements exist. A hydrological model for estimating dry season flows in ungauged catchments, based on recession curve behaviour, has been developed to address this problem. Observed flows were fitted to a second order storage model to enable average annual recession behaviour to be examined. Regionalised models were developed, using a calibration set of 26 catchments, to predict three recession curve parameters: the storage constant; the initial recession flow and the start date of the recession. Relationships were identified between: the storage constant and catchment area; the initial recession flow and elevation (acting as a surrogate for rainfall; and the start date of the recession and geographic location. An independent set of 13 catchments was used to evaluate the robustness of the models. The regional models predicted the average volume of water in an annual recession period (1st of October to the 1st of February with an average error of 8%, while mid-January flows were predicted to within ±50% for 79% of the catchments in the data set. Keywords: Himalaya, recession curve, water resources, ungauged catchment, regionalisation, low flows

  14. Disagreement between Hydrological and Land Surface models on the water budgets in the Arctic: why is this and which of them is right?

    Science.gov (United States)

    Blyth, E.; Martinez-de la Torre, A.; Ellis, R.; Robinson, E.

    2017-12-01

    The fresh-water budget of the Artic region has a diverse range of impacts: the ecosystems of the region, ocean circulation response to Arctic freshwater, methane emissions through changing wetland extent as well as the available fresh water for human consumption. But there are many processes that control the budget including a seasonal snow packs building and thawing, freezing soils and permafrost, extensive organic soils and large wetland systems. All these processes interact to create a complex hydrological system. In this study we examine a suite of 10 models that bring all those processes together in a 25 year reanalysis of the global water budget. We assess their performance in the Arctic region. There are two approaches to modelling fresh-water flows at large scales, referred to here as `Hydrological' and `Land Surface' models. While both approaches include a physically based model of the water stores and fluxes, the Land Surface models links the water flows to an energy-based model for processes such as snow melt and soil freezing. This study will analyse the impact of that basic difference on the regional patterns of evapotranspiration, runoff generation and terrestrial water storage. For the evapotranspiration, the Hydrological models tend to have a bigger spatial range in the model bias (difference to observations), implying greater errors compared to the Land-Surface models. For instance, some regions such as Eastern Siberia have consistently lower Evaporation in the Hydrological models than the Land Surface models. For the Runoff however, the results are the other way round with a slightly higher spatial range in bias for the Land Surface models implying greater errors than the Hydrological models. A simple analysis would suggest that Hydrological models are designed to get the runoff right, while Land Surface models designed to get the evapotranspiration right. Tracing the source of the difference suggests that the difference comes from the treatment

  15. Evaluation of Spatial Pattern of Altered Flow Regimes on a River Network Using a Distributed Hydrological Model.

    Science.gov (United States)

    Ryo, Masahiro; Iwasaki, Yuichi; Yoshimura, Chihiro; Saavedra V, Oliver C

    2015-01-01

    Alteration of the spatial variability of natural flow regimes has been less studied than that of the temporal variability, despite its ecological importance for river ecosystems. Here, we aimed to quantify the spatial patterns of flow regime alterations along a river network in the Sagami River, Japan, by estimating river discharge under natural and altered flow conditions. We used a distributed hydrological model, which simulates hydrological processes spatiotemporally, to estimate 20-year daily river discharge along the river network. Then, 33 hydrologic indices (i.e., Indicators of Hydrologic Alteration) were calculated from the simulated discharge to estimate the spatial patterns of their alterations. Some hydrologic indices were relatively well estimated such as the magnitude and timing of maximum flows, monthly median flows, and the frequency of low and high flow pulses. The accuracy was evaluated with correlation analysis (r > 0.4) and the Kolmogorov-Smirnov test (α = 0.05) by comparing these indices calculated from both observed and simulated discharge. The spatial patterns of the flow regime alterations varied depending on the hydrologic indices. For example, both the median flow in August and the frequency of high flow pulses were reduced by the maximum of approximately 70%, but these strongest alterations were detected at different locations (i.e., on the mainstream and the tributary, respectively). These results are likely caused by different operational purposes of multiple water control facilities. The results imply that the evaluation only at discharge gauges is insufficient to capture the alteration of the flow regime. Our findings clearly emphasize the importance of evaluating the spatial pattern of flow regime alteration on a river network where its discharge is affected by multiple water control facilities.

  16. Surface roughness effects on turbulent Couette flow

    Science.gov (United States)

    Lee, Young Mo; Lee, Jae Hwa

    2017-11-01

    Direct numerical simulation of a turbulent Couette flow with two-dimensional (2-D) rod roughness is performed to examine the effects of the surface roughness. The Reynolds number based on the channel centerline laminar velocity (Uco) and channel half height (h) is Re =7200. The 2-D rods are periodically arranged with a streamwise pitch of λ = 8 k on the bottom wall, and the roughness height is k = 0.12 h. It is shown that the wall-normal extent for the logarithmic layer is significantly shortened in the rough-wall turbulent Couette flow, compared to a turbulent Couette flow with smooth wall. Although the Reynolds stresses are increased in a turbulent channel flow with surface roughness in the outer layer due to large-scale ejection motions produced by the 2-D rods, those of the rough-wall Couette flow are decreased. Isosurfaces of the u-structures averaged in time suggest that the decrease of the turbulent activity near the centerline is associated with weakened large-scale counter-rotating roll modes by the surface roughness. This research was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2017R1D1A1A09000537) and the Ministry of Science, ICT & Future Planning (NRF-2017R1A5A1015311).

  17. Hydrology of prairie wetlands: Understanding the integrated surface-water and groundwater processes

    Science.gov (United States)

    Hayashi, Masaki; van der Kamp, Garth; Rosenberry, Donald O.

    2016-01-01

    Wetland managers and policy makers need to make decisions based on a sound scientific understanding of hydrological and ecological functions of wetlands. This article presents an overview of the hydrology of prairie wetlands intended for managers, policy makers, and researchers new to this field (e.g., graduate students), and a quantitative conceptual framework for understanding the hydrological functions of prairie wetlands and their responses to changes in climate and land use. The existence of prairie wetlands in the semi-arid environment of the Prairie-Pothole Region (PPR) depends on the lateral inputs of runoff water from their catchments because mean annual potential evaporation exceeds precipitation in the PPR. Therefore, it is critically important to consider wetlands and catchments as highly integrated hydrological units. The water balance of individual wetlands is strongly influenced by runoff from the catchment and the exchange of groundwater between the central pond and its moist margin. Land-use practices in the catchment have a sensitive effect on runoff and hence the water balance. Surface and subsurface storage and connectivity among individual wetlands controls the diversity of pond permanence within a wetland complex, resulting in a variety of eco-hydrological functionalities necessary for maintaining the integrity of prairie-wetland ecosystems.

  18. Long-term flow forecasts based on climate and hydrologic modeling: Uruguay River basin

    Science.gov (United States)

    Tucci, Carlos Eduardo Morelli; Clarke, Robin Thomas; Collischonn, Walter; da Silva Dias, Pedro Leite; de Oliveira, Gilvan Sampaio

    2003-07-01

    This paper describes a procedure for predicting seasonal flow in the Rio Uruguay drainage basin (area 75,000 km2, lying in Brazilian territory), using sequences of future daily rainfall given by the global climate model (GCM) of the Brazilian agency for climate prediction (Centro de Previsão de Tempo e Clima, or CPTEC). Sequences of future daily rainfall given by this model were used as input to a rainfall-runoff model appropriate for large drainage basins. Forecasts of flow in the Rio Uruguay were made for the period 1995-2001 of the full record, which began in 1940. Analysis showed that GCM forecasts underestimated rainfall over almost all the basin, particularly in winter, although interannual variability in regional rainfall was reproduced relatively well. A statistical procedure was used to correct for the underestimation of rainfall. When the corrected rainfall sequences were transformed to flow by the hydrologic model, forecasts of flow in the Rio Uruguay basin were better than forecasts based on historic mean or median flows by 37% for monthly flows and by 54% for 3-monthly flows.

  19. Recession-based hydrological models for estimating low flows in ungauged catchments in the Himalayas

    Science.gov (United States)

    Rees, H. G.; Holmes, M. G. R.; Young, A. R.; Kansakar, S. R.

    The Himalayan region of Nepal and northern India experiences hydrological extremes from monsoonal floods during July to September, when most of the annual precipitation falls, to periods of very low flows during the dry season (December to February). While the monsoon floods cause acute disasters such as loss of human life and property, mudslides and infrastructure damage, the lack of water during the dry season has a chronic impact on the lives of local people. The management of water resources in the region is hampered by relatively sparse hydrometerological networks and consequently, many resource assessments are required in catchments where no measurements exist. A hydrological model for estimating dry season flows in ungauged catchments, based on recession curve behaviour, has been developed to address this problem. Observed flows were fitted to a second order storage model to enable average annual recession behaviour to be examined. Regionalised models were developed, using a calibration set of 26 catchments, to predict three recession curve parameters: the storage constant; the initial recession flow and the start date of the recession. Relationships were identified between: the storage constant and catchment area; the initial recession flow and elevation (acting as a surrogate for rainfall); and the start date of the recession and geographic location. An independent set of 13 catchments was used to evaluate the robustness of the models. The regional models predicted the average volume of water in an annual recession period (1st of October to the 1st of February) with an average error of 8%, while mid-January flows were predicted to within ±50% for 79% of the catchments in the data set.

  20. Characterizing Flow and Suspended Sediment Trends in the Sacramento River Basin, CA Using Hydrologic Simulation Program - FORTRAN (HSPF)

    Science.gov (United States)

    Stern, M. A.; Flint, L. E.; Flint, A. L.; Wright, S. A.; Minear, J. T.

    2014-12-01

    A watershed model of the Sacramento River Basin, CA was developed to simulate streamflow and suspended sediment transport to the San Francisco Bay Delta (SFBD) for fifty years (1958-2008) using the Hydrological Simulation Program - FORTRAN (HSPF). To compensate for the large model domain and sparse data, rigorous meteorological development and characterization of hydraulic geometry were employed to spatially distribute climate and hydrologic processes in unmeasured locations. Parameterization techniques sought to include known spatial information for tributaries such as soil information and slope, and then parameters were scaled up or down during calibration to retain the spatial characteristics of the land surface in un-gaged areas. Accuracy was assessed by comparing model calibration to measured streamflow. Calibration and validation of the Sacramento River ranged from "good" to "very good" performance based upon a "goodness-of-fit" statistical guideline. Model calibration to measured sediment loads were underestimated on average by 39% for the Sacramento River, and model calibration to suspended sediment concentrations were underestimated on average by 22% for the Sacramento River. Sediment loads showed a slight decreasing trend from 1958-2008 and was significant (p < 0.0025) in the lower 50% of stream flows. Hypothetical climate change scenarios were developed using the Climate Assessment Tool (CAT). Several wet and dry scenarios coupled with temperature increases were imposed on the historical base conditions to evaluate sensitivity of streamflow and sediment on potential changes in climate. Wet scenarios showed an increase of 9.7 - 17.5% in streamflow, a 7.6 - 17.5% increase in runoff, and a 30 - 93% increase in sediment loads. The dry scenarios showed a roughly 5% decrease in flow and runoff, and a 16 - 18% decrease in sediment loads. The base hydrology was most sensitive to a temperature increase of 1.5 degrees Celsius and an increase in storm intensity and

  1. Surface-acoustic-wave (SAW) flow sensor

    Science.gov (United States)

    Joshi, Shrinivas G.

    1991-03-01

    The use of a surface-acoustic-wave (SAW) device to measure the rate of gas flow is described. A SAW oscillator heated to a suitable temperature above ambient is placed in the path of a flowing gas. Convective cooling caused by the gas flow results in a change in the oscillator frequency. A 73-MHz oscillator fabricated on 128 deg rotated Y-cut lithium niobate substrate and heated to 55 C above ambient shows a frequency variation greater than 142 kHz for flow-rate variation from 0 to 1000 cu cm/min. The output of the sensor can be calibrated to provide a measurement of volume flow rate, pressure differential across channel ports, or mass flow rate. High sensitivity, wide dynamic range, and direct digital output are among the attractive features of this sensor. Theoretical expressions for the sensitivity and response time of the sensor are derived. It is shown that by using ultrasonic Lamb waves propagating in thin membranes, a flow sensor with faster response than a SAW sensor can be realized.

  2. Numerical modelling of surface hydrology and near-surface hydrogeology at Forsmark. Site descriptive modelling SDM. Site Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Bosson, Emma (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Gustafsson, Lars-Goeran; Sassner, Mona (DHI Sverige AB, Stockholm (Sweden))

    2008-09-15

    SKB is currently performing site investigations at two potential sites for a final repository for spent nuclear fuel. This report presents results of water flow and solute transport modelling of the Forsmark site. The modelling reported in this document focused on the near-surface groundwater, i.e. groundwater in Quaternary deposits and shallow rock, and surface water systems, and was performed using the MIKE SHE tool. The most recent site data used in the modelling were delivered in the Forsmark 2.3 dataset, which had its 'data freeze' on March 31, 2007. The present modelling is performed in support of the final version of the Forsmark site description that is produced during the site investigation phase. In this work, the hydrological modelling system MIKE SHE has been used to describe near-surface groundwater flow and the contact between groundwater and surface water at the Forsmark site. The surface water system at Forsmark is described with the one-dimensional 'channel flow' modelling tool MIKE 11, which is fully and dynamically integrated with MIKE SHE. The MIKE SHE model was updated with data from the F2.3 data freeze. The main updates concerned the geological description of the saturated zone and the time series data on water levels and surface water discharges. The time series data used as input data and for calibration and validation was extended until the Forsmark 2.3 data freeze (March 31, 2007). The present work can be subdivided into the following four parts: 1. Update of the numerical flow model. 2. Sensitivity analysis and calibration of the model parameters. 3. Validation of the calibrated model, followed by evaluation and identification of discrepancies between measurements and model results. 4. Additional sensitivity analysis and calibration in order to resolve the problems identified in point three above. The main actions taken during the calibration can be summarised as follows: 1. The potential evapotranspiration was

  3. Coupling impervious surface rate derived from satellite remote sensing with distributed hydrological model for highly urbanized watershed flood forecasting

    Science.gov (United States)

    Dong, L.

    2017-12-01

    Abstract: The original urban surface structure changed a lot because of the rapid development of urbanization. Impermeable area has increased a lot. It causes great pressure for city flood control and drainage. Songmushan reservoir basin with high degree of urbanization is taken for an example. Pixel from Landsat is decomposed by Linear spectral mixture model and the proportion of urban area in it is considered as impervious rate. Based on impervious rate data before and after urbanization, an physically based distributed hydrological model, Liuxihe Model, is used to simulate the process of hydrology. The research shows that the performance of the flood forecasting of high urbanization area carried out with Liuxihe Model is perfect and can meet the requirement of the accuracy of city flood control and drainage. The increase of impervious area causes conflux speed more quickly and peak flow to be increased. It also makes the time of peak flow advance and the runoff coefficient increase. Key words: Liuxihe Model; Impervious rate; City flood control and drainage; Urbanization; Songmushan reservoir basin

  4. Evaluation of hydrological methods to obtain environmental flows in the Tulua River, Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Herendia, Lina Mabel; Carvajal-Escobar, Yesid [Universidad del Valle (Colombia)

    2008-10-15

    Most rivers in the world have been modified in their structure, form, composition or function, which has caused severe ecological and environmental alterations, such as pollution, a dramatic reduction in flow, and less environmental and recreational services. To reduce the human impact on the hydrological systems, new policies of sustainability are being developed worldwide. The aim is the sustainable and responsible use of water resources. One of them is the development and implementation of techniques to estimate environmental flows (EF) and environmental regimen flow regime (EFR). In this article, some hydrological methods used to determine EF and EFR are explained, and their implementation in the Tulua River (Valle del Cauca-Colombia). Simulation on HEC-RAS of the given flows was performed in order to examine flow and level variability. The result showed that most hydrological methods demand constant flows over time, and are specific for certain places and aquatic species, but some others calculate a variable EFR throughout the year and with some modifications can be used in Colombian Rivers. [Spanish] La mayoria de los rios en el mundo han sido modificados en su estructura, forma, composicion y funcionamiento, lo que ha provocado graves alteraciones ecologicas y ambientales, como contaminacion, disminucion excesiva de caudales, y perdida de los servicios ambientales y recreativos, entre otras. Es por esto que para reducir los impactos generadores por las actividades humanas en las cuencas, se estan desarrollando nuevas politicas en el mundo para el uso sostenible y responsable del recurso hidrico, entre las cuales se tienen el desarrollo y la aplicacion de tecnicas de estimacion de caudales ambientales (QA) o de regimenes de caudal ambiental (RQA). En el presente trabajo se explican algunos de los metodos hidrologicos usados para determinar el QA y el RQA, y se muestra la aplicacion de los mismos rios Tulua (Valle del Cauca, Colombia), y su posterior

  5. Quantifying Km-scale Hydrological Exchange Flows under Dynamic Flows and Their Influences on River Corridor Biogeochemistry

    Science.gov (United States)

    Chen, X.; Song, X.; Shuai, P.; Hammond, G. E.; Ren, H.; Zachara, J. M.

    2017-12-01

    Hydrologic exchange flows (HEFs) in rivers play vital roles in watershed ecological and biogeochemical functions due to their strong capacity to attenuate contaminants and process significant quantities of carbon and nutrients. While most of existing HEF studies focus on headwater systems with the assumption of steady-state flow, there is lack of understanding of large-scale HEFs in high-order regulated rivers that experience high-frequency stage fluctuations. The large variability of HEFs is a result of interactions between spatial heterogeneity in hydrogeologic properties and temporal variation in river discharge induced by natural or anthropogenic perturbations. Our 9-year spatially distributed dataset (water elevation, specific conductance, and temperature) combined with mechanistic hydrobiogeochemical simulations have revealed complex spatial and temporal dynamics in km-scale HEFs and their significant impacts on contaminant plume mobility and hyporheic biogeochemical processes along the Hanford Reach. Extended multidirectional flow behaviors of unconfined, river corridor groundwater were observed hundreds of meters inland from the river shore resulting from discharge-dependent HEFs. An appropriately sized modeling domain to capture the impact of regional groundwater flow as well as knowledge of subsurface structures controlling intra-aquifer hydrologic connectivity were essential to realistically model transient storage in this large-scale river corridor. This work showed that both river water and mobile groundwater contaminants could serve as effective tracers of HEFs, thus providing valuable information for evaluating and validating the HEF models. Multimodal residence time distributions with long tails were resulted from the mixture of long and short exchange pathways, which consequently impact the carbon and nutrient cycling within the river corridor. Improved understanding of HEFs using integrated observational and modeling approaches sheds light on

  6. Identifying hydrological regime and eco-flow threshold of small and medium flood of the Xiaoqing River in Jinan city

    Science.gov (United States)

    Liu, Yang; Cao, Sheng-Le

    2017-06-01

    It was known that hydrological regime was the main influencing factor of river ecosystem, but the regime of different flow rates of urban rivers was poorly understood. We collected daily inflows at the Huangtai station of the Xiaoqing River from 1960 to 2014 and divided the data into three periods. Then we calculated hydrological parameters by the method of EFCs (Environmental Flow Components) and analyzed the tendency and change rates of each component respectively in the three periods. Combined with the ecological significance of environmental flow components, we identified the small and medium flood had the greatest impact on the river regime and ecosystem. And then we used the hydraulic parameters in the good ecosystem period as control conditions, to calculate the ecological threshold of the flow component under the current situation. This study could provide technical support for restoring and improving hydrological regime and ecological environment of the Xiaoqing River in Jinan city.

  7. Understanding wetland sub-surface hydrology using geologic and isotopic signatures

    Directory of Open Access Journals (Sweden)

    P. Sahu

    2009-07-01

    Full Text Available This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW – a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also

  8. Understanding wetland sub-surface hydrology using geologic and isotopic signatures

    Science.gov (United States)

    Sikdar, P. K.; Sahu, P.

    2009-07-01

    This paper attempts to utilize hydrogeology and isotope composition of groundwater to understand the present hydrological processes prevalent in a freshwater wetland, source of wetland groundwater, surface water/groundwater interaction and mixing of groundwater of various depth zones in the aquifer. This study considers East Calcutta Wetlands (ECW) - a freshwater peri-urban inland wetland ecosystem located at the lower part of the deltaic alluvial plain of South Bengal Basin and east of Kolkata city. This wetland is well known over the world for its resource recovery systems, developed by local people through ages, using wastewater of the city. Geological investigations reveal that the sub-surface geology is completely blanketed by the Quaternary sediments comprising a succession of silty clay, sand of various grades and sand mixed with occasional gravels and thin intercalations of silty clay. At few places the top silty clay layer is absent due to scouring action of past channels. In these areas sand is present throughout the geological column and the areas are vulnerable to groundwater pollution. Groundwater mainly flows from east to west and is being over-extracted to the tune of 65×103 m3/day. δ18O and δD values of shallow and deep groundwater are similar indicating resemblance in hydrostratigraphy and climate of the recharge areas. Groundwater originates mainly from monsoonal rain with some evaporation prior to or during infiltration and partly from bottom of ponds, canals and infiltration of groundwater withdrawn for irrigation. Relatively high tritium content of the shallow groundwater indicates local recharge, while the deep groundwater with very low tritium is recharged mainly from distant areas. At places the deep aquifer has relatively high tritium, indicating mixing of groundwater of shallow and deep aquifers. Metals such as copper, lead, arsenic, cadmium, aluminium, nickel and chromium are also present in groundwater of various depths. Therefore

  9. Hydrologic test results for the Rattlesnake Ridge interbed and Pomona basalt flow top at Borehole DB-15

    International Nuclear Information System (INIS)

    Strait, S.R.; Brown, W.R.

    1983-07-01

    This report presents results and description of hydrologic test activities for the Rattlesnake Ridge interbed and Pomona basalt flow top at Borehole DB-15. Hydrologic tests conducted include constant discharge air-lift and constant discharge submersible pumping tests. An observed hydraulic head for the test interval was 409 ± 1 feet above mean sea level. Transmissivity values determined from hydrologic tests performed, ranged between 493 and 469 ft 2 /day. The best estimate of transmissivity is 480 ft 2 /day. The best estimate of equivalent hydraulic conductivity, based on an effective test thickness of 56 feet is 8.6 ft/day. 4 refs., 7 figs., 2 tabs

  10. Characteristics of Nitrogen Loss through Surface-Subsurface Flow on Red Soil Slopes of Southeast China

    Science.gov (United States)

    Zheng, Haijin; Liu, Zhao; Zuo, Jichao; Wang, Lingyun; Nie, Xiaofei

    2017-12-01

    Soil nitrogen (N) loss related to surface flow and subsurface flow (including interflow and groundwater flow) from slope lands is a global issue. A lysimetric experiment with three types of land cover (grass cover, GC; litter cover, LC; and bare land, BL) were carried out on a red soil slope land in southeast China. Total Nitrogen (TN) loss through surface flow, interflow and groundwater flow was observed under 28 natural precipitation events from 2015 to 2016. TN concentrations from subsurface flow on BL and LC plots were, on average, 2.7-8.2 and 1.5-4.4 times greater than TN concentrations from surface flow, respectively; the average concentration of TN from subsurface flow on GC was about 36-56% of that recorded from surface flow. Surface flow, interflow and groundwater flow contributed 0-15, 2-9 and 76-96%, respectively, of loss load of TN. Compared with BL, GC and LC intercepted 83-86% of TN loss through surface runoff; GC intercepted 95% of TN loss through subsurface flow while TN loss through subsurface flow on LC is 2.3 times larger than that on BL. In conclusion, subsurface flow especially groundwater flow is the dominant hydrological rout for N loss that is usually underestimated. Grass cover has the high retention of N runoff loss while litter mulch will increase N leaching loss. These findings provide scientific support to control N runoff loss from the red soil slope lands by using suitable vegetation cover and mulching techniques.

  11. Integrated water flow model and modflow-farm process: A comparison of theory, approaches, and features of two integrated hydrologic models

    Science.gov (United States)

    Dogrul, Emin C.; Schmid, Wolfgang; Hanson, Randall T.; Kadir, Tariq; Chung, Francis

    2016-01-01

    Effective modeling of conjunctive use of surface and subsurface water resources requires simulation of land use-based root zone and surface flow processes as well as groundwater flows, streamflows, and their interactions. Recently, two computer models developed for this purpose, the Integrated Water Flow Model (IWFM) from the California Department of Water Resources and the MODFLOW with Farm Process (MF-FMP) from the US Geological Survey, have been applied to complex basins such as the Central Valley of California. As both IWFM and MFFMP are publicly available for download and can be applied to other basins, there is a need to objectively compare the main approaches and features used in both models. This paper compares the concepts, as well as the method and simulation features of each hydrologic model pertaining to groundwater, surface water, and landscape processes. The comparison is focused on the integrated simulation of water demand and supply, water use, and the flow between coupled hydrologic processes. The differences in the capabilities and features of these two models could affect the outcome and types of water resource problems that can be simulated.

  12. A Hydrologic-geophysical Method for Characterizing Flow and Transport Processes Within The Vadose Zone

    International Nuclear Information System (INIS)

    Alumbaugh, David; LaBrecque, Douglas; Brainard, James; Yeh, T.C.-Jim

    2004-01-01

    The primary purpose of this project was to employ two geophysical imaging techniques, electrical resistivity tomography and cross-borehole ground penetrating radar, to image a controlled infiltration of a saline tracer under unsaturated flow conditions. The geophysical techniques have been correlated to other more traditional hydrologic measurements including neutron moisture measurements and induction conductivity logs. Images that resulted during two successive infiltrations indicate the development of what appear to be preferential pathways through the finer grained materials, although the results could also be produced by cationic capture of free ions in clays. In addition the site as well as the developing solute plume exhibits electrical anisotropy which is likely related to flow properties. However the geologic significance of this phenomenon is still under investigation

  13. A Hydrologic-geophysical Method for Characterizing Flow and Transport Processes Within The Vadose Zone

    Energy Technology Data Exchange (ETDEWEB)

    David Alumbaugh; Douglas LaBrecque; James Brainard; T.C. (Jim) Yeh

    2004-01-22

    The primary purpose of this project was to employ two geophysical imaging techniques, electrical resistivity tomography and cross-borehole ground penetrating radar, to image a controlled infiltration of a saline tracer under unsaturated flow conditions. The geophysical techniques have been correlated to other more traditional hydrologic measurements including neutron moisture measurements and induction conductivity logs. Images that resulted during two successive infiltrations indicate the development of what appear to be preferential pathways through the finer grained materials, although the results could also be produced by cationic capture of free ions in clays. In addition the site as well as the developing solute plume exhibits electrical anisotropy which is likely related to flow properties. However the geologic significance of this phenomenon is still under investigation.

  14. Are atmospheric surface layer flows ergodic?

    Science.gov (United States)

    Higgins, Chad W.; Katul, Gabriel G.; Froidevaux, Martin; Simeonov, Valentin; Parlange, Marc B.

    2013-06-01

    The transposition of atmospheric turbulence statistics from the time domain, as conventionally sampled in field experiments, is explained by the so-called ergodic hypothesis. In micrometeorology, this hypothesis assumes that the time average of a measured flow variable represents an ensemble of independent realizations from similar meteorological states and boundary conditions. That is, the averaging duration must be sufficiently long to include a large number of independent realizations of the sampled flow variable so as to represent the ensemble. While the validity of the ergodic hypothesis for turbulence has been confirmed in laboratory experiments, and numerical simulations for idealized conditions, evidence for its validity in the atmospheric surface layer (ASL), especially for nonideal conditions, continues to defy experimental efforts. There is some urgency to make progress on this problem given the proliferation of tall tower scalar concentration networks aimed at constraining climate models yet are impacted by nonideal conditions at the land surface. Recent advancements in water vapor concentration lidar measurements that simultaneously sample spatial and temporal series in the ASL are used to investigate the validity of the ergodic hypothesis for the first time. It is shown that ergodicity is valid in a strict sense above uniform surfaces away from abrupt surface transitions. Surprisingly, ergodicity may be used to infer the ensemble concentration statistics of a composite grass-lake system using only water vapor concentration measurements collected above the sharp transition delineating the lake from the grass surface.

  15. Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

    Directory of Open Access Journals (Sweden)

    C. Jackisch

    2017-07-01

    Full Text Available The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study and the hydrological processes (companion study Angermann et al., 2017, this issue.

  16. Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

    Science.gov (United States)

    Jackisch, Conrad; Angermann, Lisa; Allroggen, Niklas; Sprenger, Matthias; Blume, Theresa; Tronicke, Jens; Zehe, Erwin

    2017-07-01

    The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue).

  17. Introduction to special section on Uncertainty Assessment in Surface and Subsurface Hydrology : An overview of issues and challenges

    NARCIS (Netherlands)

    Montanari, A.; Shoemaker, C.A.; Van de Giesen, N.C.

    This paper introduces the Water Resources Research special section on Uncertainty Assessment in Surface and Subsurface Hydrology. Over the past years, hydrological literature has seen a large increase in the number of papers dealing with uncertainty. In this article, we present an overview of the

  18. The Water Cycle from Space: Use of Satellite Data in Land Surface Hydrology and Water Resource Management

    Science.gov (United States)

    Laymon, Charles; Blankenship, Clay; Khan, Maudood; Limaye, Ashutosh; Hornbuckle, Brian; Rowlandson, Tracy

    2010-01-01

    This slide presentation reviews how our understanding of the water cycle is enhanced by our use of satellite data, and how this informs land surface hydrology and water resource management. It reviews how NASA's current and future satellite missions will provide Earth system data of unprecedented breadth, accuracy and utility for hydrologic analysis.

  19. [Effects of soil crusts on surface hydrology in the semiarid Loess hilly area].

    Science.gov (United States)

    Wei, Wei; Wen, Zhi; Chen, Li-Ding; Chen, Jin; Wu, Dong-Ping

    2012-11-01

    Soil crusts are distributed extensively in the Chinese Loess Plateau and play key roles in surface hydrological processes. In this study, a typical loess hilly region in Anjiagou catchment, Dingxi city, Gansu province was selected as the study region, and soil crusts in the catchment were investigated. Then, the hydrological effect of soil crusts was studied by using multi-sampling and hydrological monitoring experiments. Several key results were shown as follows. Firstly, compared with bared soil without crust cover, soil crusts can greatly reduce the bulk density, improve the porosity of soil, and raise the holding capacity of soil moisture which ranges from 1.4 to 1.9 times of that of bared soil. Secondly, the role of soil crust on rainfall interception was very significant. Moss crust was found to be strongest on rainfall interception, followed by synantectic crusts and lichen crusts. Bared soil without covering crusts was poorest in resisting rainfall splash. Thirdly, hydrological simulation experiments indicate that soil crusts play a certain positive role in promoting the water infiltration capacity, and the mean infiltration rate of the crusted soil was 2 times higher than that of the no-crust covered soils. While the accumulated infiltrated water amounts was also far higher than that of the bared soil.

  20. Assimilation of ASCAT near-surface soil moisture into the French SIM hydrological model

    Science.gov (United States)

    Draper, C.; Mahfouf, J.-F.; Calvet, J.-C.; Martin, E.; Wagner, W.

    2011-06-01

    The impact of assimilating near-surface soil moisture into the SAFRAN-ISBA-MODCOU (SIM) hydrological model over France is examined. Specifically, the root-zone soil moisture in the ISBA land surface model is constrained over three and a half years, by assimilating the ASCAT-derived surface degree of saturation product, using a Simplified Extended Kalman Filter. In this experiment ISBA is forced with the near-real time SAFRAN analysis, which analyses the variables required to force ISBA from relevant observations available before the real time data cut-off. The assimilation results are tested against ISBA forecasts generated with a higher quality delayed cut-off SAFRAN analysis. Ideally, assimilating the ASCAT data will constrain the ISBA surface state to correct for errors in the near-real time SAFRAN forcing, the most significant of which was a substantial dry bias caused by a dry precipitation bias. The assimilation successfully reduced the mean root-zone soil moisture bias, relative to the delayed cut-off forecasts, by close to 50 % of the open-loop value. The improved soil moisture in the model then led to significant improvements in the forecast hydrological cycle, reducing the drainage, runoff, and evapotranspiration biases (by 17 %, 11 %, and 70 %, respectively). When coupled to the MODCOU hydrogeological model, the ASCAT assimilation also led to improved streamflow forecasts, increasing the mean discharge ratio, relative to the delayed cut off forecasts, from 0.68 to 0.76. These results demonstrate that assimilating near-surface soil moisture observations can effectively constrain the SIM model hydrology, while also confirming the accuracy of the ASCAT surface degree of saturation product. This latter point highlights how assimilation experiments can contribute towards the difficult issue of validating remotely sensed land surface observations over large spatial scales.

  1. Preliminary hydrologic testing results: McCoy Canyon flow-top, DC-7, 3410.2-3477.6 feet and DC-8: 3407.0-3480.4 feet

    International Nuclear Information System (INIS)

    Jackson, R.L.; Moak, D.J.; Spane, F.A. Jr.

    1982-01-01

    This report describes the hydrologic tests performed for an interflow zone within the Grande Ronde Basalt at Boreholes DC-7/8. The results, along with hydrologic data from several boreholes, will provide input for hydrologic modeling of groundwater flow and solute transport to assess the feasibility of siting a nuclear waste repository beneath the Hanford Site. 7 figs., 1 tab

  2. The influence of terracettes on surface hydrology and erosion on vegetated Alpine, mountain and steep-sloping environments

    Science.gov (United States)

    Kuhn, Nikolaus; (Phil) Greenwood, Philip

    2014-05-01

    Alpine and mountain slopes represent important pathways that link high altitude grazing areas to meadows and rangelands at lower elevations. Given the often acute gradient of mountain slopes, they represent a convenient and potentially highly efficient runoff conveyance route that facilitates the downslope transfer of fine-sediment and sediment-bound nutrients and contaminants during erosion events. Above a certain gradient, many slopes host small steps, or `terracettes`. As these are generally orientated across slope, their genesis is usually attributed to a combination of soil creep, coupled with (and often accentuated by) grazing animals. Motivated by the prevalence of these distinct landform features and lack of information on their role as runoff conveyance routes, this communication reports preliminary results from an investigation to explore the possibility that terracettes may act as preferential flow-paths, with an as yet undocumented ability to greatly influence surface hydrology in mountainous and steeply-sloping environments. A ca. 40 m2 area of vegetated terracettes and section of adjacent thalweg, with gradients ranging from approximately 25-35o, were scanned using an automated Topcon IS03 Total Station at a resolution of 0.1 * 0.1 m. Data were converted to a Digital Elevation Model (DEM) in ArcGIS 10 Geographical Information System (GIS), and queried using Spatial Analyst (Surface Hydrology; Flow Accumulation function) to identify slope-sections that could act as preferential flow-pathways during runoff events. These data were supplemented by information on soil physical properties that included grain size composition, bulk density and porosity, in order to establish spatial variations in soil characteristics associated with the vertical and horizontal terracette features. Combining the digital and in-situ data indicate that the technique is able to identify preferential surface flow-paths. Such information could greatly benefit the future management

  3. Free surface flows under compensated gravity conditions

    CERN Document Server

    Dreyer, Miachel E

    2007-01-01

    This book considers the behavior of fluids in a low-gravity environment with special emphasis on application in PMD (propellant management device) systems . In the compensated gravity environment of a spacecraft, the hydrostatic pressure decreases to very low values depending on the residual acceleration, and surface tension forces become dominant. Consequently, surface tension can be used to transport and position liquids if the residual acceleration and the resulting hydrostatic pressure are small compared to the capillary pressure. One prominent application is the use of PMDs in surface-tension satellite tanks. PMDs must ensure that the tank outlet is covered with liquid whenever outflow is demanded. Furthermore, PMDs are used to ensure expulsion and refilling of tanks for liquids and gases for life support, reactants, and experiment supplies. Since most of the PMD designs are not testable on ground and thus rely on analytical or numerical concepts, this book treats three different flow problems with analy...

  4. Contribution of lateral terrestrial water flows to the regional hydrological cycle: A joint soil-atmospheric moisture tagging procedure with WRF-Hydro

    Science.gov (United States)

    Arnault, Joel; Wei, Jianhui; Zhang, Zhenyu; Wagner, Sven; Kunstmann, Harald

    2017-04-01

    Water resources management requires an accurate knowledge of the behavior of the regional hydrological cycle components, including precipitation, evapotranspiration, river discharge and soil water storage. Atmospheric models such as the Weather Research and Forecasting (WRF) model provide a tool to evaluate these components. The main drawback of these atmospheric models, however, is that the terrestrial segment of the hydrological cycle is reduced to vertical infiltration, and that lateral terrestrial water flows are neglected. Recent model developments have focused on coupled atmospheric-hydrological modeling systems, such as WRF-hydro, in order to take into account subsurface, overland and river flow. The aim of this study is to investigate the contribution of lateral terrestrial water flows to the regional hydrological cycle, with the help of a joint soil-atmospheric moisture tagging procedure. This procedure is the extended version of an existing atmospheric moisture tagging method developed in WRF and WRF-Hydro (Arnault et al. 2017). It is used to quantify the partitioning of precipitation into water stored in the soil, runoff, evapotranspiration, and potentially subsequent precipitation through regional recycling. An application to a high precipitation event on 23 June 2009 in the upper Danube river basin, Germany and Austria, is presented. Precipitating water during this day is tagged for the period 2009-2011. Its contribution to runoff and evapotranspiration decreases with time, but is still not negligible in the summer 2011. At the end of the study period, less than 5 % of the precipitating water on 23 June 2009 remains in the soil. The additionally resolved lateral terrestrial water flows in WRF-Hydro modify the partitioning between surface and underground runoff, in association with a slight increase of evapotranspiration and recycled precipitation. Reference: Arnault, J., R. Knoche, J. Wei, and H. Kunstmann (2016), Evaporation tagging and atmospheric

  5. Hydrological model calibration for derived flood frequency analysis using stochastic rainfall and probability distributions of peak flows

    Science.gov (United States)

    Haberlandt, U.; Radtke, I.

    2014-01-01

    Derived flood frequency analysis allows the estimation of design floods with hydrological modeling for poorly observed basins considering change and taking into account flood protection measures. There are several possible choices regarding precipitation input, discharge output and consequently the calibration of the model. The objective of this study is to compare different calibration strategies for a hydrological model considering various types of rainfall input and runoff output data sets and to propose the most suitable approach. Event based and continuous, observed hourly rainfall data as well as disaggregated daily rainfall and stochastically generated hourly rainfall data are used as input for the model. As output, short hourly and longer daily continuous flow time series as well as probability distributions of annual maximum peak flow series are employed. The performance of the strategies is evaluated using the obtained different model parameter sets for continuous simulation of discharge in an independent validation period and by comparing the model derived flood frequency distributions with the observed one. The investigations are carried out for three mesoscale catchments in northern Germany with the hydrological model HEC-HMS (Hydrologic Engineering Center's Hydrologic Modeling System). The results show that (I) the same type of precipitation input data should be used for calibration and application of the hydrological model, (II) a model calibrated using a small sample of extreme values works quite well for the simulation of continuous time series with moderate length but not vice versa, and (III) the best performance with small uncertainty is obtained when stochastic precipitation data and the observed probability distribution of peak flows are used for model calibration. This outcome suggests to calibrate a hydrological model directly on probability distributions of observed peak flows using stochastic rainfall as input if its purpose is the

  6. Surface Effects on Nanoscale Gas Flows

    Science.gov (United States)

    Beskok, Ali; Barisik, Murat

    2010-11-01

    3D MD simulations of linear Couette flow of argon gas confined within nano-scale channels are performed in the slip, transition and free molecular flow regimes. The velocity and density profiles show deviations from the kinetic theory based predictions in the near wall region that typically extends three molecular diameters (s) from each surface. Utilizing the Irwin-Kirkwood theorem, stress tensor components for argon gas confined in nano-channels are investigated. Outside the 3s region, three normal stress components are identical, and equal to pressure predicted using the ideal gas law, while the shear stress is a constant. Within the 3s region, the normal stresses become anisotropic and the shear stress shows deviations from its bulk value due to the surface virial effects. Utilizing the kinetic theory and MD predicted shear stress values, the tangential momentum accommodation coefficient for argon gas interacting with FCC structured walls (100) plane facing the fluid is calculated to be 0.75; this value is independent of the Knudsen number. Results show emergence of the 3s region as an additional characteristic length scale in nano-confined gas flows.

  7. 30 CFR 817.57 - Hydrologic balance: Surface activities in or adjacent to perennial or intermittent streams.

    Science.gov (United States)

    2010-07-01

    ... PERMANENT PROGRAM PERFORMANCE STANDARDS-UNDERGROUND MINING ACTIVITIES § 817.57 Hydrologic balance: Surface... by roads, railroads, conveyors, pipelines, utilities, or similar facilities. You must comply with all...

  8. Assessing River Low-Flow Uncertainties Related to Hydrological Model Calibration and Structure under Climate Change Conditions

    Directory of Open Access Journals (Sweden)

    Mélanie Trudel

    2017-03-01

    Full Text Available Low-flow is the flow of water in a river during prolonged dry weather. This paper investigated the uncertainty originating from hydrological model calibration and structure in low-flow simulations under climate change conditions. Two hydrological models of contrasting complexity, GR4J and SWAT, were applied to four sub-watersheds of the Yamaska River, Canada. The two models were calibrated using seven different objective functions including the Nash-Sutcliffe coefficient (NSEQ and six other objective functions more related to low flows. The uncertainty in the model parameters was evaluated using a PARAmeter SOLutions procedure (PARASOL. Twelve climate projections from different combinations of General Circulation Models (GCMs and Regional Circulation Models (RCMs were used to simulate low-flow indices in a reference (1970–2000 and future (2040–2070 horizon. Results indicate that the NSEQ objective function does not properly represent low-flow indices for either model. The NSE objective function applied to the log of the flows shows the lowest total variance for all sub-watersheds. In addition, these hydrological models should be used with care for low-flow studies, since they both show some inconsistent results. The uncertainty is higher for SWAT than for GR4J. With GR4J, the uncertainties in the simulations for the 7Q2 index (the 7-day low-flow value with a 2-year return period are lower for the future period than for the reference period. This can be explained by the analysis of hydrological processes. In the future horizon, a significant worsening of low-flow conditions was projected.

  9. Hydrologic assessment and numerical simulation of groundwater flow, San Juan Mine, San Juan County, New Mexico, 2010–13

    Science.gov (United States)

    Stewart, Anne M.

    2018-04-03

    Coal combustion byproducts (CCBs), which are composed of fly ash, bottom ash, and flue gas desulfurization material, produced at the coal-fired San Juan Generating Station (SJGS), located in San Juan County, New Mexico, have been buried in former surface-mine pits at the San Juan Mine, also referred to as the San Juan Coal Mine, since operations began in the early 1970s. This report, prepared by the U.S. Geological Survey in cooperation with the Mining and Minerals Division of the New Mexico Energy, Minerals and Natural Resources Department, describes results of a hydrogeologic assessment, including numerical groundwater modeling, to identify the timing of groundwater recovery and potential pathways for groundwater transport of metals that may be leached from stored CCBs and reach hydrologic receptors after operations cease. Data collected for the hydrologic assessment indicate that groundwater in at least one centrally located reclaimed surface-mining pit has already begun to recover.The U.S. Geological Survey numerical modeling package MODFLOW–NWT was used with MODPATH particle-tracking software to identify advective flow paths from CCB storage areas toward potential hydrologic receptors. Results indicate that groundwater at CCB storage areas will recover to the former steady state, or in some locations, groundwater may recover to a new steady state in 6,600 to 10,600 years at variable rates depending on the proximity to a residual cone-of-groundwater depression caused by mine dewatering and regional oil and gas pumping as well as on actual, rather than estimated, groundwater recharge and evapotranspirational losses. Advective particle-track modeling indicates that the number of particles and rates of advective transport will vary depending on hydraulic properties of the mine spoil, particularly hydraulic conductivity and porosity. Modeling results from the most conservative scenario indicate that particles can migrate from CCB repositories to either the

  10. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    Science.gov (United States)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  11. Detecting Human Hydrologic Alteration from Diversion Hydropower Requires Universal Flow Prediction Tools: A Proposed Framework for Flow Prediction in Poorly-gauged, Regulated Rivers

    Science.gov (United States)

    Kibler, K. M.; Alipour, M.

    2016-12-01

    Achieving the universal energy access Sustainable Development Goal will require great investment in renewable energy infrastructure in the developing world. Much growth in the renewable sector will come from new hydropower projects, including small and diversion hydropower in remote and mountainous regions. Yet, human impacts to hydrological systems from diversion hydropower are poorly described. Diversion hydropower is often implemented in ungauged rivers, thus detection of impact requires flow analysis tools suited to prediction in poorly-gauged and human-altered catchments. We conduct a comprehensive analysis of hydrologic alteration in 32 rivers developed with diversion hydropower in southwestern China. As flow data are sparse, we devise an approach for estimating streamflow during pre- and post-development periods, drawing upon a decade of research into prediction in ungauged basins. We apply a rainfall-runoff model, parameterized and forced exclusively with global-scale data, in hydrologically-similar gauged and ungauged catchments. Uncertain "soft" data are incorporated through fuzzy numbers and confidence-based weighting, and a multi-criteria objective function is applied to evaluate model performance. Testing indicates that the proposed framework returns superior performance (NSE = 0.77) as compared to models parameterized by rote calibration (NSE = 0.62). Confident that the models are providing `the right answer for the right reasons', our analysis of hydrologic alteration based on simulated flows indicates statistically significant hydrologic effects of diversion hydropower across many rivers. Mean annual flows, 7-day minimum and 7-day maximum flows decreased. Frequency and duration of flow exceeding Q25 decreased while duration of flows sustained below the Q75 increased substantially. Hydrograph rise and fall rates and flow constancy increased. The proposed methodology may be applied to improve diversion hydropower design in data-limited regions.

  12. Precipitation and Hydrology Experiment Counter-Flow Spectrometer and Impactor Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Poellot, Michael [University of North Dakota

    2016-03-01

    The U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Aerial Facility (ARM AAF) counter-flow spectrometer and impactor (CSI) probe was flown on the University of North Dakota Cessna Citation research aircraft during the Integrated Precipitation and Hydrology Experiment (IPHEX). The field campaign took place during May and June of 2014 over North Carolina and its coastal waters as part of a National Aeronautics and Space Administration (NASA) Global Precipitation Measurement validation campaign. The CSI was added to the Citation instrument suite to support the involvement of Jay Mace through the NASA Advanced Composition Explorer (ACE) satellite program and flights of the NASA ER-2 aircraft, which is a civilian version of the Air Force’s U2-S reconnaissance platform. The ACE program funded extra ER-2 flights to focus on clouds that are weakly precipitating, which are also of interest to the Atmospheric System Research program sponsored by DOE.

  13. Eco-hydrological process simulations within an integrated surface water-groundwater model

    DEFF Research Database (Denmark)

    Butts, Michael; Loinaz, Maria Christina; Bauer-Gottwein, Peter

    2014-01-01

    Integrated water resources management requires tools that can quantify changes in groundwater, surface water, water quality and ecosystem health, as a result of changes in catchment management. To address these requirements we have developed an integrated eco-hydrological modelling framework...... that allows hydrologists and ecologists to represent the complex and dynamic interactions occurring between surface water, ground water, water quality and freshwater ecosystems within a catchment. We demonstrate here the practical application of this tool to two case studies where the interaction of surface...... water and ground water are important for the ecosystem. In the first, simulations are performed to understand the importance of surface water-groundwater interactions for a restored riparian wetland on the Odense River in Denmark as part of a larger investigation of water quality and nitrate retention...

  14. A critical assessment of the JULES land surface model hydrology for humid tropical environments

    Science.gov (United States)

    Zulkafli, Z.; Buytaert, W.; Onof, C.; Lavado, W.; Guyot, J. L.

    2013-03-01

    Global land surface models (LSMs) such as the Joint UK Land Environment Simulator (JULES) are originally developed to provide surface boundary conditions for climate models. They are increasingly used for hydrological simulation, for instance to simulate the impacts of land use changes and other perturbations on the water cycle. This study investigates how well such models represent the major hydrological fluxes at the relevant spatial and temporal scales - an important question for reliable model applications in poorly understood, data-scarce environments. The JULES-LSM is implemented in a 360 000 km2 humid tropical mountain basin of the Peruvian Andes-Amazon at 12-km grid resolution, forced with daily satellite and climate reanalysis data. The simulations are evaluated using conventional discharge-based evaluation methods, and by further comparing the magnitude and internal variability of the basin surface fluxes such as evapotranspiration, throughfall, and surface and subsurface runoff of the model with those observed in similar environments elsewhere. We find reasonably positive model efficiencies and high correlations between the simulated and observed streamflows, but high root-mean-square errors affecting the performance in smaller, upper sub-basins. We attribute this to errors in the water balance and JULES-LSM's inability to model baseflow. We also found a tendency to under-represent the high evapotranspiration rates of the region. We conclude that strategies to improve the representation of tropical systems to be (1) addressing errors in the forcing and (2) incorporating local wetland and regional floodplain in the subsurface representation.

  15. Groundwater flow modeling for near-field of a hypothetical near-surface disposal facility

    International Nuclear Information System (INIS)

    Park, H. Y.; Park, J. W.; Jang, G. M.; Kim, C. R.

    2000-01-01

    For a hypothetical near-surface radioactive disposal facility, the behavior of groundwater flow around the near-field of disposal vault located at the unsaturated zone were analyzed. Three alternative conceptual models proposed as the hydraulic barrier layer design were simulated to assess the hydrologic performance of engineered barriers for the facility. In order to evaluate the seepage possibility of the infiltrated water passed through the final disposal cover after the facility closure, the flow path around and water flux through each disposal vault were compared. The hydrologic parameters variation that accounts for the long-term aging and degradation of the cover and engineered materials was considered in the simulations. The results showed that it is necessary to construct the hydraulic barrier at the upper and sides of the vault, and that, for this case, achieving design hydraulic properties of bentonite/sand mixture barrier in the as-built condition is crucial to limit the seepage into the waste

  16. Primer: Using Watershed Modeling System (WMS) for Gridded Surface Subsurface Hydrologic Analysis (GSSHA) Data Development - WMS 6.1 and GSSHA 1.43C

    National Research Council Canada - National Science Library

    Downer, Charles

    2003-01-01

    This document is a primer for use of the Watershed Modeling System (WMS) interface with the physically based, distributed-parameter hydrologic model Gridded Surface Subsurface Hydrologic Analysis (GSSHA...

  17. Spatiotemporal variability of hydrologic soil properties and the implications for overland flow and land management in a peri-urban Mediterranean catchment

    Science.gov (United States)

    Ferreira, C. S. S.; Walsh, R. P. D.; Steenhuis, T. S.; Shakesby, R. A.; Nunes, J. P. N.; Coelho, C. O. A.; Ferreira, A. J. D.

    2015-06-01

    Planning of semi-urban developments is often hindered by a lack of knowledge on how changes in land-use affect catchment hydrological response. The temporal and spatial patterns of overland flow source areas and their connectivity in the landscape, particularly in a seasonal climate, remain comparatively poorly understood. This study investigates seasonal variations in factors influencing runoff response to rainfall in a peri-urban catchment in Portugal characterized by a mosaic of landscape units and a humid Mediterranean climate. Variations in surface soil moisture, hydrophobicity and infiltration capacity were measured in six different landscape units (defined by land-use on either sandstone or limestone) in nine monitoring campaigns at key times over a one-year period. Spatiotemporal patterns in overland flow mechanisms were found. Infiltration-excess overland flow was generated in rainfalls during the dry summer season in woodland on both sandstone and limestone and on agricultural soils on limestone due probably in large part to soil hydrophobicity. In wet periods, saturation overland flow occurred on urban and agricultural soils located in valley bottoms and on shallow soils upslope. Topography, water table rise and soil depth determined the location and extent of saturated areas. Overland flow generated in upslope source areas potentially can infiltrate in other landscape units downslope where infiltration capacity exceeds rainfall intensity. Hydrophilic urban and agricultural-sandstone soils were characterized by increased infiltration capacity during dry periods, while forest soils provided potential sinks for overland flow when hydrophilic in the winter wet season. Identifying the spatial and temporal variability of overland flow sources and sinks is an important step in understanding and modeling flow connectivity and catchment hydrologic response. Such information is important for land managers in order to improve urban planning to minimize flood risk.

  18. Empirical assessment of effects of urbanization on event flow hydrology in watersheds of Canada's Great Lakes-St Lawrence basin

    Science.gov (United States)

    Trudeau, M. P.; Richardson, Murray

    2016-10-01

    We conducted an empirical hydrological analysis of high-temporal resolution streamflow records for 27 watersheds within 11 river systems in the Greater Toronto Region of the Canadian Great Lakes basin. Our objectives were to model the event-scale flow response of watersheds to urbanization and to test for scale and threshold effects. Watershed areas ranged from 37.5 km2 to 806 km2 and urban percent land cover ranged from less than 0.1-87.6%. Flow records had a resolution of 15-min increments and were available over a 42-year period, allowing for detailed assessment of changes in event-scale flow response with increasing urban land use during the post-freshet period (May 26 to November 15). Empirical statistical models were developed for flow characteristics including total runoff, runoff coefficient, eightieth and ninety-fifth percentile rising limb event runoff and mean rising limb event acceleration. Changes in some of these runoff metrics began at very low urban land use (acceleration increased with increasing urban cover, thus causing 80th percentile runoff depths to be reached sooner. These results indicate the potential for compromised water balance when cumulative changes are considered at the watershed scale. No abrupt or threshold changes in hydrologic characteristics were identified along the urban land use gradient. A positive interaction of urban percent land use and watershed size indicated a scale effect on total runoff. Overall, the results document compromised hydrologic stability attributable to urbanization during a period with no detectable change in rainfall patterns. They also corroborate literature recommendations for spatially distributed low impact urban development techniques; measures would be needed throughout the urbanized area of a watershed to dampen event-scale hydrologic responses to urbanization. Additional research is warranted into event-scale hydrologic trends with urbanization in other regions, in particular rising limb event

  19. Common problematic aspects of coupling hydrological models with groundwater flow models on the river catchment scale

    Directory of Open Access Journals (Sweden)

    R. Barthel

    2006-01-01

    Full Text Available Model coupling requires a thorough conceptualisation of the coupling strategy, including an exact definition of the individual model domains, the "transboundary" processes and the exchange parameters. It is shown here that in the case of coupling groundwater flow and hydrological models – in particular on the regional scale – it is very important to find a common definition and scale-appropriate process description of groundwater recharge and baseflow (or "groundwater runoff/discharge" in order to achieve a meaningful representation of the processes that link the unsaturated and saturated zones and the river network. As such, integration by means of coupling established disciplinary models is problematic given that in such models, processes are defined from a purpose-oriented, disciplinary perspective and are therefore not necessarily consistent with definitions of the same process in the model concepts of other disciplines. This article contains a general introduction to the requirements and challenges of model coupling in Integrated Water Resources Management including a definition of the most relevant technical terms, a short description of the commonly used approach of model coupling and finally a detailed consideration of the role of groundwater recharge and baseflow in coupling groundwater models with hydrological models. The conclusions summarize the most relevant problems rather than giving practical solutions. This paper aims to point out that working on a large scale in an integrated context requires rethinking traditional disciplinary workflows and encouraging communication between the different disciplines involved. It is worth noting that the aspects discussed here are mainly viewed from a groundwater perspective, which reflects the author's background.

  20. Measurement of Effect of Chemical Reactions on the Hydrologic Properties of Fractured Glass Media Using a Tri-axial Flow and Transport Apparatus

    International Nuclear Information System (INIS)

    Saripalli, Prasad; Lindberg, Michael J.; Meyer, P. D.

    2006-01-01

    Understanding the effect of chemical reactions on the hydrologic properties of sub-surface media is critical to many natural and engineered sub-surface systems. Methods and information for such characterization of fractured media are severely lacking. Influence of glass corrosion (precipitation and dissolution) reactions on fractured glass blocks HAN28 and LAWBP1, two candidate waste glass forms for a proposed immobilized low-activity waste (ILAW) disposal facility at the Hanford, WA site, was investigated. Flow and tracer transport experiments were conducted in such randomly and multiply fractured ILAW glass blocks, before and after subjecting them to corrosion using Vapor Hydration Testing (VHT) at 200 C temperature and 200 psig (1379 KPa) pressure, causing the precipitation of alteration products. A tri-axial fractured media flow and transport experimental apparatus, which allows the simultaneous measurement of flow and transport properties and their anisotropy, has been designed and built for this purpose. Such apparatus for fractured media characterization are being reported in the literature only recently. Hydraulic properties of fractured blocks were measured in different orientations and along different cardinal directions, before and after glass corrosion reactions. Miscible displacement experiments using a non-reactive dye were also conducted, before and after glass corrosion reactions, to study the tracer transport behavior through such media. Initial efforts to analyze breakthrough curve (BTC) data using a 1D Advection Dispersion Equation (ADE) solution revealed that a different fractured media transport model may be necessary for such interpretation. It was found that glass reactions can have a significant influence on the hydrologic properties of fractured ILAW glass media. The methods and results are unique and useful to better understand the effect of chemical reactions on the hydrologic properties of fractured geomedia in general and glass media in

  1. Impact of model structure on flow simulation and hydrological realism: from a lumped to a semi-distributed approach

    Science.gov (United States)

    Garavaglia, Federico; Le Lay, Matthieu; Gottardi, Fréderic; Garçon, Rémy; Gailhard, Joël; Paquet, Emmanuel; Mathevet, Thibault

    2017-08-01

    Model intercomparison experiments are widely used to investigate and improve hydrological model performance. However, a study based only on runoff simulation is not sufficient to discriminate between different model structures. Hence, there is a need to improve hydrological models for specific streamflow signatures (e.g., low and high flow) and multi-variable predictions (e.g., soil moisture, snow and groundwater). This study assesses the impact of model structure on flow simulation and hydrological realism using three versions of a hydrological model called MORDOR: the historical lumped structure and a revisited formulation available in both lumped and semi-distributed structures. In particular, the main goal of this paper is to investigate the relative impact of model equations and spatial discretization on flow simulation, snowpack representation and evapotranspiration estimation. Comparison of the models is based on an extensive dataset composed of 50 catchments located in French mountainous regions. The evaluation framework is founded on a multi-criterion split-sample strategy. All models were calibrated using an automatic optimization method based on an efficient genetic algorithm. The evaluation framework is enriched by the assessment of snow and evapotranspiration modeling against in situ and satellite data. The results showed that the new model formulations perform significantly better than the initial one in terms of the various streamflow signatures, snow and evapotranspiration predictions. The semi-distributed approach provides better calibration-validation performance for the snow cover area, snow water equivalent and runoff simulation, especially for nival catchments.

  2. Characterizing the Surface Connectivity of Depressional Wetlands: Linking Remote Sensing and Hydrologic Modeling Approaches

    Science.gov (United States)

    Christensen, J.; Evenson, G. R.; Vanderhoof, M.; Wu, Q.; Golden, H. E.; Lane, C.

    2017-12-01

    Surface connectivity of wetlands in the 700,000 km2 Prairie Pothole Region of North America (PPR) can occur through fill-spill and fill-merge mechanisms, with some wetlands eventually spilling into stream/river systems. These wetland-to-wetland and wetland-to-stream connections vary both spatially and temporally in PPR watersheds and are important to understanding hydrologic and biogeochemical processes in the landscape. To explore how to best characterize spatial and temporal variability in aquatic connectivity, we compared three approaches, 1) hydrological modeling alone, 2) remotely-sensed data alone, and 3) integrating remotely-sensed data into a hydrological model. These approaches were tested in the Pipestem Creek Watershed, North Dakota across a drought to deluge cycle (1990-2011). A Soil and Water Assessment Tool (SWAT) model was modified to include the water storage capacity of individual non-floodplain wetlands identified in the National Wetland Inventory (NWI) dataset. The SWAT-NWI model simulated the water balance and storage of each wetland and the temporal variability of their hydrologic connections between wetlands during the 21-year study period. However, SWAT-NWI only accounted for fill-spill, and did not allow for the expansion and merging of wetlands situated within larger depressions. Alternatively, we assessed the occurrence of fill-merge mechanisms using inundation maps derived from Landsat images on 19 cloud-free days during the 21 years. We found fill-merge mechanisms to be prevalent across the Pipestem watershed during times of deluge. The SWAT-NWI model was then modified to use LiDAR-derived depressions that account for the potential maximum depression extent, including the merging of smaller wetlands. The inundation maps were used to evaluate the ability of the SWAT-depression model to simulate fill-merge dynamics in addition to fill-spill dynamics throughout the study watershed. Ultimately, using remote sensing to inform and validate

  3. Potential effects of surface coal mining on the hydrology of the Corral Creek area, Hanging Woman Creek coal field, southeastern Montana

    Science.gov (United States)

    McClymonds, N.E.

    1984-01-01

    The Corral Creek area of the Hanging Woman Creek coal field, 9 miles east of the Decker coal mines near the Tongue River, contains large reserves of Federal coal that have been identified for potential lease sale. A hydrologic study was conducted in the area to describe existing hydrologic systems and to study assess potential impacts of surface coal mining on local water resources. Hydrogeologic data collected indicate that aquifers are coal and sandstone beds within the Tongue River Member of the Fort Union Formation (Paleocene age) and sand and gravel in valley alluvium (Pleistocene and Holocene age). Surface-water resources are limited to a few spring-fed stock ponds in the higher parts of the area and the intermittent flow of Corral Creek near the mouth. Most of the stock ponds in the area become dry by midsummer. Mining of the Anderson coal bed would remove three stock wells and would lower the potentiometric surface within the coal and sandstone aquifers. The alluvial aquifer beneath Corral Creek and South Fork would be removed. Although mining would alter the existing hydrologic systems and remove several shallow wells, alternative ground-water supplies are available that could be developed to replace those lost by mining. (USGS)

  4. HOBE – a hydrological observatory

    DEFF Research Database (Denmark)

    Jensen, Karsten Høgh; Illangasekare, Tissa

    2011-01-01

    In this paper a short introducO on is given to the Danish hydrological observatory—HOBE. We describe characteristics of the catchment, which is subject to experimental and modeling investigations. An overview is given of the research reported in this special section of the journal, which includes...... 11 papers of original research covering precipitation, evapotranspiration, emission of greenhouse gasses, unsaturated flow, groundwater–surface water interaction, and climate change impacts on hydrology....

  5. Biological soil crust and disturbance controls on surface hydrology in a semi-arid ecosystem

    Science.gov (United States)

    Faist, Akasha M; Herrick, Jeffrey E.; Belnap, Jayne; Van Zee, Justin W; Barger, Nichole N

    2017-01-01

    Biological soil crust communities (biocrusts) play an important role in surface hydrologic processes in dryland ecosystems, and these processes may then be dramatically altered with soil surface disturbance. In this study, we examined biocrust hydrologic responses to disturbance at different developmental stages on sandy soils on the Colorado Plateau. Our results showed that all disturbance (trampling, scalping and trampling+scalping) of the early successional light cyanobacterial biocrusts generally reduced runoff. In contrast, trampling well-developed dark-cyano-lichen biocrusts increased runoff and sediment loss relative to intact controls. Scalping did not increase runoff, implying that soil aggregate structure was important to the infiltration process. Well-developed, intact dark biocrusts generally had lower runoff, low sediment loss, and highest aggregate stability whereas the less-developed light biocrusts were highest in runoff and sediment loss when compared to the controls. These results suggest the importance of maintaining the well-developed dark biocrusts, as they are beneficial for lowering runoff and reducing soil loss and redistribution on the landscape. These data also suggest that upslope patches of light biocrust may either support water transport to downslope vegetation patches or alternatively this runoff may place dark biocrust patches at risk of disruption and loss, given that light patches increase runoff and thus soil erosion potential.

  6. The development of a surface hydrology model for use in radiological safety assessments

    International Nuclear Information System (INIS)

    Little, R.H.; Ashton, J.

    1991-01-01

    A detailed understanding and quantification of geosphere and biosphere water movements is vital when assessing the impact of a radioactive waste repository. Not only is water important in the transport of radionuclides from the repository into the geosphere and hence into the biosphere, but it is also important in the transport of radionuclides within the biosphere and their transport to humans. Although geosphere water fluxes have traditionally been rigorously quantified, the quantification of biosphere water fluxes has been far less rigorous. In order to redress the balance, Associated Nuclear Services Ltd (ANS) have proposed to develop a surface hydrology model for use within radiological assessments undertaken by Her Majesty's Inspectorate of Pollution (HMIP) of the United Kingdom Department of the Environment (UKDoE). It is proposed that the deterministic, lumped, quasi-physical/semi-empirical approach of conceptual models should be adopted for the model. The model will be sufficiently flexible to be applicable to a wide range of catchments, as well as a variety of temporal and spatial scales. It is envisaged that the model will have a variety of uses within the HMIP assessment methodology including the identification of significant surface hydrological processes, the provision of input data for assessment codes and the study of the biosphere-geosphere interface. (17 refs., 4 figs.)

  7. Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment

    Directory of Open Access Journals (Sweden)

    P. Rodgers

    2005-01-01

    Full Text Available δ18O measurements in precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2 River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped within the catchment, was reflected in stream water at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of apparently more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment difference using an exponential flow model to provide indicative estimates of mean stream water residence times, which varied between approximately 3 and 14 months. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond that of the smallest (ca. 1 km2 headwater catchment scale. Instead, the interaction of catchment soil cover and topography appeared to be the dominant controlling influence. Where sub-catchments had extensive peat coverage, responsive hydrological pathways produced seasonally variable δ18O signatures in runoff with short mean residence times (ca. 3 months. In contrast, areas dominated by steeper slopes, more freely draining soils and larger groundwater storage in shallow valley-bottom aquifers, deeper flow paths allow for more effective mixing and damping of δ18O indicating longer residence times (>12 months. These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at larger spatial scales.

  8. Hydrological assessment of atmospheric forcing uncertainty in the Euro-Mediterranean area using a land surface model

    Science.gov (United States)

    Gelati, Emiliano; Decharme, Bertrand; Calvet, Jean-Christophe; Minvielle, Marie; Polcher, Jan; Fairbairn, David; Weedon, Graham P.

    2018-04-01

    Physically consistent descriptions of land surface hydrology are crucial for planning human activities that involve freshwater resources, especially in light of the expected climate change scenarios. We assess how atmospheric forcing data uncertainties affect land surface model (LSM) simulations by means of an extensive evaluation exercise using a number of state-of-the-art remote sensing and station-based datasets. For this purpose, we use the CO2-responsive ISBA-A-gs LSM coupled with the CNRM version of the Total Runoff Integrated Pathways (CTRIP) river routing model. We perform multi-forcing simulations over the Euro-Mediterranean area (25-75.5° N, 11.5° W-62.5° E, at 0.5° resolution) from 1979 to 2012. The model is forced using four atmospheric datasets. Three of them are based on the ERA-Interim reanalysis (ERA-I). The fourth dataset is independent from ERA-Interim: PGF, developed at Princeton University. The hydrological impacts of atmospheric forcing uncertainties are assessed by comparing simulated surface soil moisture (SSM), leaf area index (LAI) and river discharge against observation-based datasets: SSM from the European Space Agency's Water Cycle Multi-mission Observation Strategy and Climate Change Initiative projects (ESA-CCI), LAI of the Global Inventory Modeling and Mapping Studies (GIMMS), and Global Runoff Data Centre (GRDC) river discharge. The atmospheric forcing data are also compared to reference datasets. Precipitation is the most uncertain forcing variable across datasets, while the most consistent are air temperature and SW and LW radiation. At the monthly timescale, SSM and LAI simulations are relatively insensitive to forcing uncertainties. Some discrepancies with ESA-CCI appear to be forcing-independent and may be due to different assumptions underlying the LSM and the remote sensing retrieval algorithm. All simulations overestimate average summer and early-autumn LAI. Forcing uncertainty impacts on simulated river discharge are

  9. Hydrologic test results for the upper Cohassett flow interior at borehole RRL-2, Hanford Site, Washington State

    International Nuclear Information System (INIS)

    Strait, S.R.; Spane, F.A. Jr.

    1984-03-01

    The results and description of hydrologic test activities for the upper Cohassett flow interior at borehole RRL-2 over the depth interval 3,057 to 3,172 feet are presented in this report. Hydrologic tests conducted include an over-pressure pulse test and a constant head injection test. Preliminary results from hydrologic tests performed indicate transmissivity values ranging from 1.8 x 10 -6 to 1.7 x 10 -4 square feet per day, with an assigned best estimate of 1.7 x 10 -4 square feet per day. The best estimates of equivalent hydraulic conductivity, based on a thickness for the effective test interval of 115 feet, is 1.5 x 10 -6 feet per day. Best-estimate values obtained from testing are consistent with results previously reported for similar Grande Ronde Basalt horizons. 12 refs., 6 figs., 3 tabs

  10. Hydrologic mechanisms governing fluid flow in partially saturated, fractured, porous tuff at Yucca Mountain

    International Nuclear Information System (INIS)

    Wang, J.S.Y.; Narasimhan, T.N.

    1984-10-01

    In contrast to the saturated zone where fluid moves rapidly along fractures, the fractures (with apertures large relative to the size of matrix pores) will desaturate first during drainage process and the bulk of fluid flow would be through interconnected pores in the matrix. Within a partially drained fracture, the presence of a relatively continuous air phase will produce practically an infinite resistance to liquid flow in the direction parallel to the fracture. The residual liquid will be held by capillary force in regions around fracture contact areas where the apertures are small. Normal to the fracture surfaces, the drained portion of the fractures will reduce the effective area for liquid flow from one matrix block to another matrix block. A general statistical theory is constructed for flow along the fracture and for flow between the matrix blocks to the fractures under partially saturated conditions. Results are obtained from an aperture distribution model for fracture saturation, hydraulic conductivity, and effective matrix-fracture flow areas as functions of pressure. Drainage from a fractured tuff column is simulated. The parameters for the simulations are deduced from fracture surface characteristics, spacings and orientations based on core analyses, and from matrix characteristics curve based on laboratory measurements. From the cases simulated for the fractured, porous column with discrete vertical and horizontal fractures and porous matrix blocks explicitly taken into account, it is observed that the highly transient changes from fully saturated conditions to partially saturated conditions are extremely sensitive to the fracture properties. However, the quasi-steady changes of the fluid flow of a partially saturated, fractured, porous system could be approximately simulated without taking the fractures into account. 22 references, 16 figures

  11. Improving Simulations of Extreme Flows by Coupling a Physically-based Hydrologic Model with a Machine Learning Model

    Science.gov (United States)

    Mohammed, K.; Islam, A. S.; Khan, M. J. U.; Das, M. K.

    2017-12-01

    With the large number of hydrologic models presently available along with the global weather and geographic datasets, streamflows of almost any river in the world can be easily modeled. And if a reasonable amount of observed data from that river is available, then simulations of high accuracy can sometimes be performed after calibrating the model parameters against those observed data through inverse modeling. Although such calibrated models can succeed in simulating the general trend or mean of the observed flows very well, more often than not they fail to adequately simulate the extreme flows. This causes difficulty in tasks such as generating reliable projections of future changes in extreme flows due to climate change, which is obviously an important task due to floods and droughts being closely connected to people's lives and livelihoods. We propose an approach where the outputs of a physically-based hydrologic model are used as an input to a machine learning model to try and better simulate the extreme flows. To demonstrate this offline-coupling approach, the Soil and Water Assessment Tool (SWAT) was selected as the physically-based hydrologic model, the Artificial Neural Network (ANN) as the machine learning model and the Ganges-Brahmaputra-Meghna (GBM) river system as the study area. The GBM river system, located in South Asia, is the third largest in the world in terms of freshwater generated and forms the largest delta in the world. The flows of the GBM rivers were simulated separately in order to test the performance of this proposed approach in accurately simulating the extreme flows generated by different basins that vary in size, climate, hydrology and anthropogenic intervention on stream networks. Results show that by post-processing the simulated flows of the SWAT models with ANN models, simulations of extreme flows can be significantly improved. The mean absolute errors in simulating annual maximum/minimum daily flows were minimized from 4967

  12. How Important Is Connectivity for Surface Water Fluxes? A Generalized Expression for Flow Through Heterogeneous Landscapes

    Science.gov (United States)

    Larsen, Laurel G.; Ma, Jie; Kaplan, David

    2017-10-01

    How important is hydrologic connectivity for surface water fluxes through heterogeneous floodplains, deltas, and wetlands? While significant for management, this question remains poorly addressed. Here we adopt spatial resistance averaging, based on channel and patch configuration metrics quantifiable from aerial imagery, to produce an upscaled rate law for discharge. Our model suggests that patch coverage largely controls discharge sensitivity, with smaller effects from channel connectivity and vegetation patch fractal dimension. However, connectivity and patch configuration become increasingly important near the percolation threshold and at low water levels. These effects can establish positive feedbacks responsible for substantial flow change in evolving landscapes (14-36%, in our Everglades case study). Connectivity also interacts with other drivers; flow through poorly connected hydroscapes is less resilient to perturbations in other drivers. Finally, we found that flow through heterogeneous patches is alone sufficient to produce non-Manning flow-depth relationships commonly observed in wetlands but previously attributed to depth-varying roughness.

  13. Using the PCRaster-POLFLOW approach to GIS-based modelling of coupled groundwater-surface water hydrology in the Forsmark Area

    International Nuclear Information System (INIS)

    Jarsjoe, Jerker; Shibuo, Yoshihiro; Destouni, Georgia

    2004-09-01

    The catchment-scale hydrologic modelling approach PCRaster-POLFLOW permits the integration of environmental process modelling functions with classical GIS functions such as database maintenance and screen display. It has previously successfully been applied at relatively large river basins and catchments, such as Rhine, Elbe and Norrstroem, for modelling stream water flow and nutrient transport. In this study, we review the PCRaster-POLFLOW modelling approach and apply it using a relatively fine spatial resolution to the smaller catchment of Forsmark. As input we use data from SKB's database, which includes detailed data from Forsmark (and Simpevarp), since these locations are being investigated as part of the process to find a suitable location for a deep repository for spent nuclear fuel. We show, by comparison with independently measured, area-averaged runoff data, that the PCRaster-POLFLOW model produces results that, without using site-specific calibration, agree well with these independent measurements. In addition, we deliver results for four planned hydrological stations within the Forsmark catchment thus allowing for future direct comparisons with streamflow monitoring. We also show that, and how, the PCRaster-POLFLOW model in its present state can be used for predicting average seasonal streamflow. The present modelling exercise provided insights into possible ways of extending and using the PCRaster-POLFLOW model for applications beyond its current main focus of surface water hydrology. In particular, regarding analysis of possible surface water-groundwater interactions, we identify the Analytic Element Method for groundwater modelling together with its GIS-based pre- and post processor ArcFlow as suitable and promising for use in combination with the PCRaster-POLFLOW modelling approach. Furthermore, for transport modelling, such as that of radionuclides entering the coupled shallow groundwater-surface water hydrological system from possible deep

  14. Using the PCRaster-POLFLOW approach to GIS-based modelling of coupled groundwater-surface water hydrology in the Forsmark Area

    Energy Technology Data Exchange (ETDEWEB)

    Jarsjoe, Jerker; Shibuo, Yoshihiro; Destouni, Georgia [Stockholm Univ. (Sweden). Dept. of Physical Geography and Quaternary Geology

    2004-09-01

    The catchment-scale hydrologic modelling approach PCRaster-POLFLOW permits the integration of environmental process modelling functions with classical GIS functions such as database maintenance and screen display. It has previously successfully been applied at relatively large river basins and catchments, such as Rhine, Elbe and Norrstroem, for modelling stream water flow and nutrient transport. In this study, we review the PCRaster-POLFLOW modelling approach and apply it using a relatively fine spatial resolution to the smaller catchment of Forsmark. As input we use data from SKB's database, which includes detailed data from Forsmark (and Simpevarp), since these locations are being investigated as part of the process to find a suitable location for a deep repository for spent nuclear fuel. We show, by comparison with independently measured, area-averaged runoff data, that the PCRaster-POLFLOW model produces results that, without using site-specific calibration, agree well with these independent measurements. In addition, we deliver results for four planned hydrological stations within the Forsmark catchment thus allowing for future direct comparisons with streamflow monitoring. We also show that, and how, the PCRaster-POLFLOW model in its present state can be used for predicting average seasonal streamflow. The present modelling exercise provided insights into possible ways of extending and using the PCRaster-POLFLOW model for applications beyond its current main focus of surface water hydrology. In particular, regarding analysis of possible surface water-groundwater interactions, we identify the Analytic Element Method for groundwater modelling together with its GIS-based pre- and post processor ArcFlow as suitable and promising for use in combination with the PCRaster-POLFLOW modelling approach. Furthermore, for transport modelling, such as that of radionuclides entering the coupled shallow groundwater-surface water hydrological system from possible deep

  15. The hydrological cycle in the high Pamir Mountains: how temperature and seasonal precipitation distribution influence stream flow in the Gunt catchment, Tajikistan

    Science.gov (United States)

    Pohl, E.; Knoche, M.; Gloaguen, R.; Andermann, C.; Krause, P.

    2014-12-01

    Complex climatic interactions control hydrological processes in high mountains that in their turn regulate the erosive forces shaping the relief. To unravel the hydrological cycle of a glaciated watershed (Gunt River) considered representative of the Pamirs' hydrologic regime we developed a remote sensing-based approach. At the boundary between two distinct climatic zones dominated by Westerlies and Indian summer monsoon, the Pamir is poorly instrumented and only a few in situ meteorological and hydrological data are available. We adapted a suitable conceptual distributed hydrological model (J2000g). Interpolations of the few available in situ data are inadequate due to strong, relief induced, spatial heterogeneities. Instead we use raster data, preferably from remote sensing sources depending on availability and validation. We evaluate remote sensing-based precipitation and temperature products. MODIS MOD11 surface temperatures show good agreement with in situ data, perform better than other products and represent a good proxy for air temperatures. For precipitation we tested remote sensing products as well as the HAR10 climate model data and the interpolation-based APHRODITE dataset. All products show substantial differences both in intensity and seasonal distribution with in-situ data. Despite low resolutions, the datasets are able to sustain high model efficiencies (NSE ≥0.85). In contrast to neighbouring regions in the Himalayas or the Hindukush, discharge is dominantly the product of snow and glacier melt and thus temperature is the essential controlling factor. 80% of annual precipitation is provided as snow in winter and spring contrasting peak discharges during summer. Hence, precipitation and discharge are negatively correlated and display complex hysteresis effects that allow to infer the effect of inter-annual climatic variability on river flow. We infer the existence of two subsurface reservoirs. The groundwater reservoir (providing 40% of annual

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

    Science.gov (United States)

    Lettenmaier, D. P.

    2010-12-01

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

  17. Surface Hydrological Processes of Rock Glaciated Basins in the San Juan Mountains, Colorado

    Science.gov (United States)

    Mateo, E. I.

    2017-12-01

    Glaciers in the western United States have been examined in terms of their summer meltwater contributions to regional hydrological systems. In the San Juan Mountains of Colorado where glaciers do not and cannot exist due to a rising zero-degree isotherm, rock glaciers take the place of valley glaciers during the summer runoff period. Most of the rock glaciers in Colorado are located on a northerly slope aspect, however, there are multiple in the southwest region of the state that occur on different aspects. This study asked how slope aspect and rising air temperatures influenced the hydrological processes of streams below rock glaciers in the San Juan Mountains during the 2016 summer season. This project focused on three basins, Yankee Boy basin, Blue Lakes basin, and Mill Creek basin, which are adjacent to each other and share a common peak, Gilpin Peak. Findings of this one-season study showed that air temperature significantly influenced stream discharge below each rock glacier. Discharge and air temperature patterns indicate a possible air temperature threshold during late summer when rock glacier melt increased at a greater rate. The results also suggest that slope aspect of rock glacier basins influences stream discharge, but temperature and precipitation are likely larger components of the melt regimes. The continuation of data collection during the 2017 summer season has allowed for more detailed analysis of the relationship between air temperature and rock glacier melt. This continual expansion of the original dataset is crucial for understanding the hydrological processes of surface runoff below rock glaciers.

  18. Surface roughness influences on the behaviour of flow inside microchannels

    Science.gov (United States)

    Farias, M. H.; Castro, C. S.; Garcia, D. A.; Henrique, J. S.

    2018-03-01

    This work discusses influence of the surface roughness on the behavior of liquids flowing inside microchannels. By measuring the flow profile using the micro-PIV technique, the flow of water inside two rectangular microchannels of different wall roughness and in a circular smooth microchannel was studied. Comparisons were made among the experimental results, showing that a metrological approach concerning surface characteristics of microdevices is required to ensure reliability of the measurements for flow analyses in microfluidic processes.

  19. Inverse modeling of hydrologic parameters using surface flux and runoff observations in the Community Land Model

    Science.gov (United States)

    Sun, Y.; Hou, Z.; Huang, M.; Tian, F.; Leung, L. Ruby

    2013-12-01

    This study demonstrates the possibility of inverting hydrologic parameters using surface flux and runoff observations in version 4 of the Community Land Model (CLM4). Previous studies showed that surface flux and runoff calculations are sensitive to major hydrologic parameters in CLM4 over different watersheds, and illustrated the necessity and possibility of parameter calibration. Both deterministic least-square fitting and stochastic Markov-chain Monte Carlo (MCMC)-Bayesian inversion approaches are evaluated by applying them to CLM4 at selected sites with different climate and soil conditions. The unknowns to be estimated include surface and subsurface runoff generation parameters and vadose zone soil water parameters. We find that using model parameters calibrated by the sampling-based stochastic inversion approaches provides significant improvements in the model simulations compared to using default CLM4 parameter values, and that as more information comes in, the predictive intervals (ranges of posterior distributions) of the calibrated parameters become narrower. In general, parameters that are identified to be significant through sensitivity analyses and statistical tests are better calibrated than those with weak or nonlinear impacts on flux or runoff observations. Temporal resolution of observations has larger impacts on the results of inverse modeling using heat flux data than runoff data. Soil and vegetation cover have important impacts on parameter sensitivities, leading to different patterns of posterior distributions of parameters at different sites. Overall, the MCMC-Bayesian inversion approach effectively and reliably improves the simulation of CLM under different climates and environmental conditions. Bayesian model averaging of the posterior estimates with different reference acceptance probabilities can smooth the posterior distribution and provide more reliable parameter estimates, but at the expense of wider uncertainty bounds.

  20. Hydrology and geochemistry of a surface coal mine in northwestern Colorado

    Science.gov (United States)

    Williams, R.S.; Clark, G.M.

    1994-01-01

    The hydrology and geochemistry of a reclaimed coal mine in northwestern Colorado were monitored during water years 1988 and 1989. Some data also were collected in water years 1987 and 1990. This report describes (1) the sources of hydrologic recharge to and discharge from reclaimed spoil, (2) the relative contributions of recharge to the reclaimed spoil aquifer from identified source waters and the rate of water movement from those sources to the reclaimed spoil, and (3) the geochemical reactions that control water quality in reclaimed spoil. The study area was at a dip-slope coal mine encompassing about 7 square miles with land slopes of varying aspect. The area was instrumented and monitored at five sites; two sites had unmined and reclaimed- spoil areas adjacent to each other and three sites were unmined. The mined areas had been reclaimed. Instrumentation at the study sites included 1 climate station, 3 rain gages, 19 soil-water access tubes, 2 lysimeters, 18 wells completed in bedrock, 7 wells completed in reclaimed spoil, and 2 surface- water gaging stations. The results of the study indicate that the reclaimed spoil is recharged from surface recharge and underburden aquifers. Discharge, as measured by lysimeters, was about 3 inches per year and occurred during and after snowmelt. Hydraulic-head measurements indicated a potential for ground-water movement from deeper to shallower aquifers. Water levels rose in the reclaimed-spoil aquifer and spring discharge at the toe of the spoil slopes increased rapidly in response to snowmelt. Water chemistry, stable isotopes, geochemical models, and mass-balance calculations indicate that surface recharge and the underburden aquifers each contribute about 50 percent of the water to the reclaimed-spoil aquifers. Geochemical information indicates that pyrite oxidation and dissolution of carbonate and efflorescent sulfate minerals control the water chemistry of the reclaimed-spoil aquifer.

  1. Development and Application of Improved Long-Term Datasets of Surface Hydrology for Texas

    Directory of Open Access Journals (Sweden)

    Kyungtae Lee

    2017-01-01

    Full Text Available Freshwater availability and agricultural production are key factors for sustaining the fast growing population and economy in the state of Texas, which is the third largest state in terms of agricultural production in the United States. This paper describes a long-term (1918–2011 grid-based (1/8° surface hydrological dataset for Texas at a daily time step based on simulations from the Variable Infiltration Capacity (VIC hydrological model. The model was calibrated and validated against observed streamflow over 10 Texas river basins. The simulated soil moisture was also evaluated using in situ observations. Results suggest that there is a decreasing trend in precipitation and an increasing trend in temperature in most of the basins. Droughts and floods were reconstructed and analyzed. In particular, the spatially distributed severity and duration of major Texas droughts were compared to identify new characteristics. The modeled flood recurrence interval and the return period were also compared with observations. Results suggest the performance of extreme flood simulations needs further improvement. This dataset is expected to serve as a benchmark which may contribute to water resources management and to mitigating agricultural drought, especially in the context of understanding the effects of climate change on crop yield in Texas.

  2. Predictive occurrence models for coastal wetland plant communities: delineating hydrologic response surfaces with multinomial logistic regression

    Science.gov (United States)

    Snedden, Gregg A.; Steyer, Gregory D.

    2013-01-01

    Understanding plant community zonation along estuarine stress gradients is critical for effective conservation and restoration of coastal wetland ecosystems. We related the presence of plant community types to estuarine hydrology at 173 sites across coastal Louisiana. Percent relative cover by species was assessed at each site near the end of the growing season in 2008, and hourly water level and salinity were recorded at each site Oct 2007–Sep 2008. Nine plant community types were delineated with k-means clustering, and indicator species were identified for each of the community types with indicator species analysis. An inverse relation between salinity and species diversity was observed. Canonical correspondence analysis (CCA) effectively segregated the sites across ordination space by community type, and indicated that salinity and tidal amplitude were both important drivers of vegetation composition. Multinomial logistic regression (MLR) and Akaike's Information Criterion (AIC) were used to predict the probability of occurrence of the nine vegetation communities as a function of salinity and tidal amplitude, and probability surfaces obtained from the MLR model corroborated the CCA results. The weighted kappa statistic, calculated from the confusion matrix of predicted versus actual community types, was 0.7 and indicated good agreement between observed community types and model predictions. Our results suggest that models based on a few key hydrologic variables can be valuable tools for predicting vegetation community development when restoring and managing coastal wetlands.

  3. Predictive occurrence models for coastal wetland plant communities: Delineating hydrologic response surfaces with multinomial logistic regression

    Science.gov (United States)

    Snedden, Gregg A.; Steyer, Gregory D.

    2013-02-01

    Understanding plant community zonation along estuarine stress gradients is critical for effective conservation and restoration of coastal wetland ecosystems. We related the presence of plant community types to estuarine hydrology at 173 sites across coastal Louisiana. Percent relative cover by species was assessed at each site near the end of the growing season in 2008, and hourly water level and salinity were recorded at each site Oct 2007-Sep 2008. Nine plant community types were delineated with k-means clustering, and indicator species were identified for each of the community types with indicator species analysis. An inverse relation between salinity and species diversity was observed. Canonical correspondence analysis (CCA) effectively segregated the sites across ordination space by community type, and indicated that salinity and tidal amplitude were both important drivers of vegetation composition. Multinomial logistic regression (MLR) and Akaike's Information Criterion (AIC) were used to predict the probability of occurrence of the nine vegetation communities as a function of salinity and tidal amplitude, and probability surfaces obtained from the MLR model corroborated the CCA results. The weighted kappa statistic, calculated from the confusion matrix of predicted versus actual community types, was 0.7 and indicated good agreement between observed community types and model predictions. Our results suggest that models based on a few key hydrologic variables can be valuable tools for predicting vegetation community development when restoring and managing coastal wetlands.

  4. Identifying and Evaluating the Relationships that Control a Land Surface Model's Hydrological Behavior

    Science.gov (United States)

    Koster, Randal D.; Mahanama, Sarith P.

    2012-01-01

    The inherent soil moisture-evaporation relationships used in today 's land surface models (LSMs) arguably reflect a lot of guesswork given the lack of contemporaneous evaporation and soil moisture observations at the spatial scales represented by regional and global models. The inherent soil moisture-runoff relationships used in the LSMs are also of uncertain accuracy. Evaluating these relationships is difficult but crucial given that they have a major impact on how the land component contributes to hydrological and meteorological variability within the climate system. The relationships, it turns out, can be examined efficiently and effectively with a simple water balance model framework. The simple water balance model, driven with multi-decadal observations covering the conterminous United States, shows how different prescribed relationships lead to different manifestations of hydrological variability, some of which can be compared directly to observations. Through the testing of a wide suite of relationships, the simple model provides estimates for the underlying relationships that operate in nature and that should be operating in LSMs. We examine the relationships currently used in a number of different LSMs in the context of the simple water balance model results and make recommendations for potential first-order improvements to these LSMs.

  5. Viscous flows stretching and shrinking of surfaces

    CERN Document Server

    Mehmood, Ahmer

    2017-01-01

    This authored monograph provides a detailed discussion of the boundary layer flow due to a moving plate. The topical focus lies on the 2- and 3-dimensional case, considering axially symmetric and unsteady flows. The author derives a criterion for the self-similar and non-similar flow, and the turbulent flow due to a stretching or shrinking sheet is also discussed. The target audience primarily comprises research experts in the field of boundary layer flow, but the book will also be beneficial for graduate students.

  6. Hydrologic modeling in a marsh-mangrove ecotone: Predicting wetland surface water and salinity response to restoration in the Ten Thousand Islands region of Florida, USA

    Science.gov (United States)

    Michot, B.D.; Meselhe, E.A.; Krauss, Ken W.; Shrestha, Surendra; From, Andrew S.; Patino, Eduardo

    2017-01-01

    At the fringe of Everglades National Park in southwest Florida, United States, the Ten Thousand Islands National Wildlife Refuge (TTINWR) habitat has been heavily affected by the disruption of natural freshwater flow across the Tamiami Trail (U.S. Highway 41). As the Comprehensive Everglades Restoration Plan (CERP) proposes to restore the natural sheet flow from the Picayune Strand Restoration Project area north of the highway, the impact of planned measures on the hydrology in the refuge needs to be taken into account. The objective of this study was to develop a simple, computationally efficient mass balance model to simulate the spatial and temporal patterns of water level and salinity within the area of interest. This model could be used to assess the effects of the proposed management decisions on the surface water hydrological characteristics of the refuge. Surface water variations are critical to the maintenance of wetland processes. The model domain is divided into 10 compartments on the basis of their shared topography, vegetation, and hydrologic characteristics. A diversion of +10% of the discharge recorded during the modeling period was simulated in the primary canal draining the Picayune Strand forest north of the Tamiami Trail (Faka Union Canal) and this discharge was distributed as overland flow through the refuge area. Water depths were affected only modestly. However, in the northern part of the refuge, the hydroperiod, i.e., the duration of seasonal flooding, was increased by 21 days (from 115 to 136 days) for the simulation during the 2008 wet season, with an average water level rise of 0.06 m. The average salinity over a two-year period in the model area just south of Tamiami Trail was reduced by approximately 8 practical salinity units (psu) (from 18 to 10 psu), whereas the peak dry season average was reduced from 35 to 29 psu (by 17%). These salinity reductions were even larger with greater flow diversions (+20%). Naturally, the reduction

  7. Coupled Monitoring and Inverse Modeling to Investigate Surface - Subsurface Hydrological and Thermal Dynamics in the Arctic Tundra

    Science.gov (United States)

    Tran, A. P.; Dafflon, B.; Hubbard, S. S.; Bisht, G.; Peterson, J.; Ulrich, C.; Romanovsky, V. E.; Kneafsey, T. J.; Wu, Y.

    2015-12-01

    Quantitative characterization of the soil surface-subsurface hydrological and thermal processes is essential as they are primary factors that control the biogeochemical processes, ecological landscapes and greenhouse gas fluxes. In the Artic region, the surface-subsurface hydrological and thermal regimes co-interact and are both largely influenced by soil texture and soil organic content. In this study, we present a coupled inversion scheme that jointly inverts hydrological, thermal and geophysical data to estimate the vertical profiles of clay, sand and organic contents. Within this inversion scheme, the Community Land Model (CLM4.5) serves as a forward model to simulate the land-surface energy balance and subsurface hydrological-thermal processes. Soil electrical conductivity (from electrical resistivity tomography), temperature and water content are linked together via petrophysical and geophysical models. Particularly, the inversion scheme accounts for the influences of the soil organic and mineral content on both of the hydrological-thermal dynamics and the petrophysical relationship. We applied the inversion scheme to the Next Generation Ecosystem Experiments (NGEE) intensive site in Barrow, AK, which is characterized by polygonal-shaped arctic tundra. The monitoring system autonomously provides a suite of above-ground measurements (e.g., precipitation, air temperature, wind speed, short-long wave radiation, canopy greenness and eddy covariance) as well as below-ground measurements (soil moisture, soil temperature, thaw layer thickness, snow thickness and soil electrical conductivity), which complement other periodic, manually collected measurements. The preliminary results indicate that the model can well reproduce the spatiotemporal dynamics of the soil temperature, and therefore, accurately predict the active layer thickness. The hydrological and thermal dynamics are closely linked to the polygon types and polygon features. The results also enable the

  8. Surface flow in severe plastic deformation of metals by sliding

    International Nuclear Information System (INIS)

    Mahato, A; Yeung, H; Chandrasekar, S; Guo, Y

    2014-01-01

    An in situ study of flow in severe plastic deformation (SPD) of surfaces by sliding is described. The model system – a hard wedge sliding against a metal surface – is representative of surface conditioning processes typical of manufacturing, and sliding wear. By combining high speed imaging and image analysis, important characteristics of unconstrained plastic flow inherent to this system are highlighted. These characteristics include development of large plastic strains on the surface and in the subsurface by laminar type flow, unusual fluid-like flow with vortex formation and surface folding, and defect and particle generation. Preferred conditions, as well as undesirable regimes, for surface SPD are demarcated. Implications for surface conditioning in manufacturing, modeling of surface deformation and wear are discussed

  9. Radiochemical analyses of surface water from U.S. Geological Survey hydrologic bench-mark stations

    Science.gov (United States)

    Janzer, V.J.; Saindon, L.G.

    1972-01-01

    The U.S. Geological Survey's program for collecting and analyzing surface-water samples for radiochemical constituents at hydrologic bench-mark stations is described. Analytical methods used during the study are described briefly and data obtained from 55 of the network stations in the United States during the period from 1967 to 1971 are given in tabular form.Concentration values are reported for dissolved uranium, radium, gross alpha and gross beta radioactivity. Values are also given for suspended gross alpha radioactivity in terms of natural uranium. Suspended gross beta radioactivity is expressed both as the equilibrium mixture of strontium-90/yttrium-90 and as cesium-137.Other physical parameters reported which describe the samples include the concentrations of dissolved and suspended solids, the water temperature and stream discharge at the time of the sample collection.

  10. A novel physical eco-hydrological model concept for preferential flow based on experimental applications.

    Science.gov (United States)

    Jackisch, Conrad; van Schaik, Loes; Graeff, Thomas; Zehe, Erwin

    2014-05-01

    Preferential flow through macropores often determines hydrological characteristics - especially regarding runoff generation and fast transport of solutes. Macropore settings may yet be very different in nature and dynamics, depending on their origin. While biogenic structures follow activity cycles (e.g. earth worms) and population conditions (e.g. roots), pedogenic and geogenic structures may depend on water stress (e.g. cracks) or large events (e.g. flushed voids between skeleton and soil pipes) or simply persist (e.g. bedrock interface). On the one hand, such dynamic site characteristics can be observed in seasonal changes in its reaction to precipitation. On the other hand, sprinkling experiments accompanied by tracers or time-lapse 3D Ground-Penetrating-Radar are suitable tools to determine infiltration patterns and macropore configuration. However, model representation of the macropore-matrix system is still problematic, because models either rely on effective parameters (assuming well-mixed state) or on explicit advection strongly simplifying or neglecting interaction with the diffusive flow domain. Motivated by the dynamic nature of macropores, we present a novel model approach for interacting diffusive and advective water, solutes and energy transport in structured soils. It solely relies on scale- and process-aware observables. A representative set of macropores (data from sprinkling experiments) determines the process model scale through 1D advective domains. These are connected to a 2D matrix domain which is defined by pedo-physical retention properties. Water is represented as particles. Diffusive flow is governed by a 2D random walk of these particles while advection may take place in the macropore domain. Macropore-matrix interaction is computed as dissipation of the advective momentum of a particle by its experienced drag from the matrix domain. Through a representation of matrix and macropores as connected diffusive and advective domains for water

  11. Relationship among soil surface properties, hydrology and nitrogen cycling along a climatological gradient in drylands

    Science.gov (United States)

    Zaady, E.; Segoli, M.; Eldridge, D. J.; Groffman, P. M.; Boeken, B.; Shachak, M.

    2009-04-01

    Primary production and nutrient cycling in dryland systems are limited by water supply. There are two groups of primary producers, high biomass production plants and low biomass producing organisms found in biological soil crusts (BSC's), which control energy flow, nutrient cycling and hydrology. Biological or biogenic soil crusts are common in the world's drylands, from dry sub-humid to hyper-arid systems. The crusts are formed by communities of microphytes, mainly cyanobacteria, green algae, mosses, and lichens. The extracellular polysaccharide materials produced by the crust organisms attach soil particles, creating a solid horizontal layer of crust. Biological soil crusts modify soil quality by (1) aggregating soil particles, thereby reducing wind and water erosion; (2) reducing water infiltration, causing overland water run-off; and (3) N fixation and C sequestration. Dryland landscapes are two phase mosaic composed of BSC and high production patches. Development or loss of BSC may trigger changes in the spatial distribution of the patch types and therefore transitions between functional and degraded ecosystem states. We present a conceptual model depicting the function of each patch type and the link between them. Taking into account the contrast between low and high vegetation cover of dryland systems and their role in controlling soil nitrogen and water flows. The model describes the functioning of dryland systems with low biomass producing crust organisms cover, low rainfall, low top soil water and production, which cause low infiltration rate, low N uptake, nitrate accumulation, high evaporation and runoff. This leads to leaching of nitrates, oxygen depletion with high anaerobic conditions, high denitrification rates and N loss, resulting in low plant cover and soil organic matter i.e., degraded soil. It also depicts the functioning of the high production plants under low rainfall regimes resulting in low rates of N and energy flows. The model shows that

  12. Effects on surface hydrology and near-surface hydrogeology of an open repository in Laxemar Results of modelling with MIKE SHE

    International Nuclear Information System (INIS)

    Maartensson, Erik; Gustafsson, Lars-Goeran; Bosson, Emma

    2009-10-01

    This report presents the methodology and the results from the modelling of an open repository for spent nuclear fuel in Laxemar. Specifically, the present work analyses the hydrological effects of the planned repository during the construction and operational phases when it is open, i.e. air-filled, and hence may cause a disturbance of the hydrological conditions in the surroundings. The numerical modelling is based on the SDM-Site Laxemar MIKE SHE model. The modelling was divided into three steps. The first step was to update the SDM-Site Laxemar model with a new hydrogeological bedrock model. The other main updates were an increase of the depth of the MIKE SHE model domain, enhanced vertical computational resolution and that the drainage of the Aespoe Hard Rock Laboratory was included in the model. The resulting model was used to simulate undisturbed natural conditions. The next step was to describe the open repository conditions, using Laxemar layout D2, by implementing the access tunnel, the repository tunnels and shafts in the model, and to simulate the consequences for the surface hydrology caused by an open repository under different conditions. The final step was a sensitivity analysis that aimed to investigate the sensitivity of the modelled effects of the open repository to the hydrogeological properties of the bedrock and the Quaternary deposits, the sediments under the sea, and changes in boundary conditions. The model covers an area of 34 km 2 . The groundwater divides were assumed to coincide with the surface water divides; thus, a no-flow boundary condition was used at the horizontal boundaries, except in the Quaternary deposit layers towards the sea where a time-varying boundary condition describing the sea-level in the area was used. In the bedrock layers, however, a no-flow boundary condition was applied. Also the bottom boundary was described as a no-flow boundary. The transient top boundary condition was based on meteorological data gathered at

  13. New advection schemes for free surface flows

    International Nuclear Information System (INIS)

    Pavan, Sara

    2016-01-01

    The purpose of this thesis is to build higher order and less diffusive schemes for pollutant transport in shallow water flows or 3D free surface flows. We want robust schemes which respect the main mathematical properties of the advection equation with relatively low numerical diffusion and apply them to environmental industrial applications. Two techniques are tested in this work: a classical finite volume method and a residual distribution technique combined with a finite element method. For both methods we propose a decoupled approach since it is the most advantageous in terms of accuracy and CPU time. Concerning the first technique, a vertex-centred finite volume method is used to solve the augmented shallow water system where the numerical flux is computed through an Harten-Lax-Van Leer-Contact Riemann solver. Starting from this solution, a decoupled approach is formulated and is preferred since it allows to compute with a larger time step the advection of a tracer. This idea was inspired by Audusse, E. and Bristeau, M.O. [13]. The Monotonic Upwind Scheme for Conservation Law, combined with the decoupled approach, is then used for the second order extension in space. The wetting and drying problem is also analysed and a possible solution is presented. In the second case, the shallow water system is entirely solved using the finite element technique and the residual distribution method is applied to the solution of the tracer equation, focusing on the case of time-dependent problems. However, for consistency reasons the resolution of the continuity equation must be considered in the numerical discretization of the tracer. In order to get second order schemes for unsteady cases a predictor-corrector scheme is used in this work. A first order but less diffusive version of the predictor-corrector scheme is also introduced. Moreover, we also present a new locally semi-implicit version of the residual distribution method which, in addition to good properties in

  14. Hydrology and numerical simulation of groundwater flow and streamflow depletion by well withdrawals in the Malad-Lower Bear River Area, Box Elder County, Utah

    Science.gov (United States)

    Stolp, Bernard J.; Brooks, Lynette E.; Solder, John

    2017-03-28

    The Malad-Lower Bear River study area in Box Elder County, Utah, consists of a valley bounded by mountain ranges and is mostly agricultural or undeveloped. The Bear and Malad Rivers enter the study area with a combined average flow of about 1,100,000 acre-feet per year (acre-ft/yr), and this surface water dominates the hydrology. Groundwater occurs in consolidated rock and basin fill. Groundwater recharge occurs from precipitation in the mountains and moves through consolidated rock to the basin fill. Recharge occurs in the valley from irrigation. Groundwater discharge occurs to rivers, springs and diffuse seepage areas, evapotranspiration, field drains, and wells. Groundwater, including springs, is a source for municipal and domestic water supply. Although withdrawal from wells is a small component of the groundwater budget, there is concern that additional groundwater development will reduce the amount of flow in the Malad River. Historical records of surface-water diversions, land use, and groundwater levels indicate relatively stable hydrologic conditions from the 1960s to the 2010s, and that current groundwater development has had little effect on the groundwater system. Average annual recharge to and discharge from the groundwater flow system are estimated to be 164,000 and 228,000 acre-ft/yr, respectively. The imbalance between recharge and discharge represents uncertainties resulting from system complexities, and the possibility of groundwater inflow from surrounding basins.This study reassesses the hydrologic system, refines the groundwater budget, and creates a numerical groundwater flow model that is used to analyze the effects of groundwater withdrawals on surface water. The model uses the detailed catalog of locations and amounts of groundwater recharge and discharge defined during this study. Calibrating the model to adequately simulate recharge, discharge, and groundwater levels results in simulated aquifer properties that can be used to understand

  15. Assimilation of ASCAT near-surface soil moisture into the SIM hydrological model over France

    Science.gov (United States)

    Draper, C.; Mahfouf, J.-F.; Calvet, J.-C.; Martin, E.; Wagner, W.

    2011-12-01

    This study examines whether the assimilation of remotely sensed near-surface soil moisture observations might benefit an operational hydrological model, specifically Météo-France's SAFRAN-ISBA-MODCOU (SIM) model. Soil moisture data derived from ASCAT backscatter observations are assimilated into SIM using a Simplified Extended Kalman Filter (SEKF) over 3.5 years. The benefit of the assimilation is tested by comparison to a delayed cut-off version of SIM, in which the land surface is forced with more accurate atmospheric analyses, due to the availability of additional atmospheric observations after the near-real time data cut-off. However, comparing the near-real time and delayed cut-off SIM models revealed that the main difference between them is a dry bias in the near-real time precipitation forcing, which resulted in a dry bias in the root-zone soil moisture and associated surface moisture flux forecasts. While assimilating the ASCAT data did reduce the root-zone soil moisture dry bias (by nearly 50%), this was more likely due to a bias within the SEKF, than due to the assimilation having accurately responded to the precipitation errors. Several improvements to the assimilation are identified to address this, and a bias-aware strategy is suggested for explicitly correcting the model bias. However, in this experiment the moisture added by the SEKF was quickly lost from the model surface due to the enhanced surface fluxes (particularly drainage) induced by the wetter soil moisture states. Consequently, by the end of each winter, during which frozen conditions prevent the ASCAT data from being assimilated, the model land surface had returned to its original (dry-biased) climate. This highlights that it would be more effective to address the precipitation bias directly, than to correct it by constraining the model soil moisture through data assimilation.

  16. Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Drici, Warda [Stoller-Navarro Joint Venture, Las Vegas, NV (United States)

    2004-02-01

    This report documents the analysis of the available hydrologic data conducted in support of the development of a Corrective Action Unit (CAU) groundwater flow model for Central and Western Pahute Mesa: CAUs 101 and 102.

  17. Influence of hydrological models on cumulative flow simulation under climate change scenarios : an application in the Baskatong watershed

    International Nuclear Information System (INIS)

    Chartier, I.

    2006-01-01

    Since Hydro-Quebec owns and operates many hydroelectric power plants, from which it draws 96 per cent of its electricity, the electric utility found it necessary to study the impact of climate change on water resources and cumulative flow. This paper described Hydro-Quebec's method for evaluating climatic change impacts using hydrological simulations, with particular reference to the Baskatong watershed in the Outaouais region of Quebec. This basin is one of 5 sub-basins within the Gatineau River. Hydro-Quebec's studies were conducted using 3 hydrological models known as MOHYSE, HSAMI and HYDROTEL; 4 general circulation models (GCM) known as HadCM3, CSIRO, ECHAM4 and CGCM3; and, 4 greenhouse gas scenarios called A1, B1, A2 and B2. GCMs were shown to have a larger impact on the final hydrological simulation result compared to greenhouse gas scenarios or the hydrological models, although the latter two did have a significant impact on the final result of the simulation. Each scenario provided long term predictions despite the use of different models. The study demonstrated that many regions will have to rely on a range of GCM for more elaborate climatic scenarios. 9 refs., 1 tab., 9 figs

  18. A Level Set Discontinuous Galerkin Method for Free Surface Flows

    DEFF Research Database (Denmark)

    Grooss, Jesper; Hesthaven, Jan

    2006-01-01

    We present a discontinuous Galerkin method on a fully unstructured grid for the modeling of unsteady incompressible fluid flows with free surfaces. The surface is modeled by embedding and represented by a levelset. We discuss the discretization of the flow equations and the level set equation...

  19. Local grid refinement for free-surface flow simulations

    NARCIS (Netherlands)

    van der Plas, Peter

    2017-01-01

    The principal goal of the current study is to explore and investigate the potential of local grid refinement for increasing the numerical efficiency of free-surface flow simulations in a practical context. In this thesis we propose a method for local grid refinement in the free-surface flow model

  20. The Effect of Model Grid Resolution on the Distributed Hydrologic Simulations for Forecasting Stream Flows and Reservoir Storage

    Science.gov (United States)

    Turnbull, S. J.

    2017-12-01

    Within the US Army Corps of Engineers (USACE), reservoirs are typically operated according to a rule curve that specifies target water levels based on the time of year. The rule curve is intended to maximize flood protection by specifying releases of water before the dominant rainfall period for a region. While some operating allowances are permissible, generally the rule curve elevations must be maintained. While this operational approach provides for the required flood control purpose, it may not result in optimal reservoir operations for multi-use impoundments. In the Russian River Valley of California a multi-agency research effort called Forecast-Informed Reservoir Operations (FIRO) is assessing the application of forecast weather and streamflow predictions to potentially enhance the operation of reservoirs in the watershed. The focus of the study has been on Lake Mendocino, a USACE project important for flood control, water supply, power generation and ecological flows. As part of this effort the Engineer Research and Development Center is assessing the ability of utilizing the physics based, distributed watershed model Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model to simulate stream flows, reservoir stages, and discharges while being driven by weather forecast products. A key question in this application is the effect of watershed model resolution on forecasted stream flows. To help resolve this question, GSSHA models of multiple grid resolutions, 30, 50, and 270m, were developed for the upper Russian River, which includes Lake Mendocino. The models were derived from common inputs: DEM, soils, land use, stream network, reservoir characteristics, and specified inflows and discharges. All the models were calibrated in both event and continuous simulation mode using measured precipitation gages and then driven with the West-WRF atmospheric model in prediction mode to assess the ability of the model to function in short term, less than one week

  1. Use of Isotopic Techniques for the Assessment of Hydrological Interaction Surface Water and Groundwater. Rio Man - Cienaga Colombia

    International Nuclear Information System (INIS)

    Palacio B, P.; Betancur V, T.; Dapena, C.

    2011-01-01

    This job integrates the first results from the studies ''Conceptual Hydrological Model for the middle and lower parts of the Man River basin using hydrological, hydrochemical and isotopic techniques'' (Palacio, 2011) and ''Hydrochemical and Isotopic techniques for the assessment of hydrological processes in the the wetlands of Bajo Cauca Antioquia'' (University of Antioquia and International Atomic Energy Agency (IAEA). The Man river basin covers an area of 688 km 2 ; with temperatures ranging from 25 to 30 o C; The average annual rainfall is 2.800 mm. The geology of the area is composed mainly of clastic sedimentary rocks of continental origin. A hydrological model of interaction between surface water and groundwater for the lower middle of the Man River basin was obtained by the use of hydrological analysis techniques. This model was refined, adjusted and validated using isotope techniques based mainly on the analysis of spatial and temporal variance of stable isotopes found in rain water, surface bodies of water such as streams and wetlands, and in an unconfined aquifer.

  2. Model of hydrological behaviour of the anthropized semiarid wetland of Las Tablas de Daimiel National Park (Spain) based on surface water-groundwater interactions

    Science.gov (United States)

    Aguilera, H.; Castaño, S.; Moreno, L.; Jiménez-Hernández, M. E.; de la Losa, A.

    2013-05-01

    Las Tablas de Daimiel National Park (TDNP) in Spain is one of the most important semiarid wetlands of the Mediterranean area. The inversion of the regional groundwater flow, primarily due to overexploitation and inadequate aquifer management, has led to degradation. The system has turned from a groundwater discharge zone into a recharge zone, and has remained mostly dry since the 1980s. High heterogeneity and complexity, enhanced by anthropogenic management action, hampers prediction of the surface-groundwater system response to flooding events. This study analyses these interactions and provides empirical evidence to define a conceptual model of flooding-infiltration-groundwater dynamics through the application of a few simple analysis tools to basic hydrological data. Relevant surface water-groundwater interactions are mainly localized in the left (west) margin of TDNP, as confirmed by the fast responses to flooding observed in the hydrochemic, hydrodynamic and isotopic data. During drying periods, small artificial and/or low-flow natural floods are followed by infiltration of evaporated poor-quality ponding water into saline low-permeability layers. The results allow an improved understanding of the hydrological behaviour essential to support efficient management practices. The relative simplicity of the methodology allows for its application in other similar complex groundwater-linked wetlands where detailed knowledge of local geology is still absent.

  3. Soil Surface Runoff Scheme for Improving Land-Hydrology and Surface Fluxes in Simple SiB (SSiB)

    Science.gov (United States)

    Sud, Y. C.; Mocko, David M.

    1999-01-01

    Evapotranspiration on land is hard to measure and difficult to simulate. On the scale of a GCM grid, there is large subgrid-scale variability of orography, soil moisture, and vegetation. Our hope is to be able to tune the biophysical constants of vegetation and soil parameters to get the most realistic space-averaged diurnal cycle of evaporation and its climatology. Field experiments such as First ISLSCP Field Experiment (FIFE), Boreal Ecosystem-Atmosphere Study (BOREAS), and LBA help a great deal in improving our evapotranspiration schemes. However, these improvements have to be matched with, and coupled to, consistent improvement in land-hydrology; otherwise, the runoff problems will intrinsically reflect on the soil moisture and evapotranspiration errors. Indeed, a realistic runoff simulation also ensures a reasonable evapotranspiration simulation provided the precipitation forcing is reliable. We have been working on all of the above problems to improve the simulated hydrologic cycle. Through our participation in the evaluation and intercomparison of land-models under the behest of Global Soil Wetness Project (GSWP), we identified a few problems with Simple SiB (SSIB; Xue et al., 1991) hydrology in regions of significant snowmelt. Sud and Mocko (1999) show that inclusion of a separate snowpack model, with its own energy budget and fluxes with the atmosphere aloft and soil beneath, helps to ameliorate some of the deficiencies of delayed snowmelt and excessive spring season runoff. Thus, much more realistic timing of melt water generation was simulated with the new snowpack model in the subsequent GSWP re-evaluations using 2 years of ISLSCP Initiative I forcing data for 1987 and 1988. However, we noted an overcorrection of the low meltwater infiltration of SSiB. While the improvement in snowmelt timing was found everywhere, the snowmelt infiltration has became excessive in some regions, e.g., Lena river basin. This leads to much reduced runoff in many basins as

  4. Transient disturbance growth in flows over convex surfaces

    Science.gov (United States)

    Karp, Michael; Hack, M. J. Philipp

    2017-11-01

    Flows over curved surfaces occur in a wide range of applications including airfoils, compressor and turbine vanes as well as aerial, naval and ground vehicles. In most of these applications the surface has convex curvature, while concave surfaces are less common. Since monotonic boundary-layer flows over convex surfaces are exponentially stable, they have received considerably less attention than flows over concave walls which are destabilized by centrifugal forces. Non-modal mechanisms may nonetheless enable significant disturbance growth which can make the flow susceptible to secondary instabilities. A parametric investigation of the transient growth and secondary instability of flows over convex surfaces is performed. The specific conditions yielding the maximal transient growth and strongest instability are identified. The effect of wall-normal and spanwise inflection points on the instability process is discussed. Finally, the role and significance of additional parameters, such as the geometry and pressure gradient, is analyzed.

  5. Development and implementation of a Variable Infiltration Capacity model of surface hydrology into the General Circulation Model

    International Nuclear Information System (INIS)

    Lettenmaier, D.P.; Stamm, J.F.; Wood, E.F.

    1993-04-01

    A Variable Infiltration Capacity (VIC) model is described for the representation of land surface hydrology in General Circulation Models (GCMs). The VIC model computes runoff as a function of the distribution of soil moisture capacity within a GCM grid cell. The major distinguishing feature of the VIC model relative to the bucket model currently used to represent the land surface in many GCMs is that it parameterizes the nonlinearity of the fraction of precipitation that infiltrates over a large area (hence the production of direct runoff) as a function of spatial average soil moisture storage, and that it models subsurface runoff between storms via a simple recession mechanism. The VIC model was incorporated into the Geophysical Fluid Dynamics Laboratory (GFDL) GCM at R15 resolution (roughly 4.5 degrees latitude by 7.5 degrees longitude). Ten-year simulations of global climate were produced using the GFDL GCM with both VIC land surface hydrology, and, for comparison purposes, the standard bucket representation. Comparison of the ten year runs using the VIC model with those using bucket hydrology showed that for the VIC run, global average runoff increased, soil moisture decreased, evaporation decreased, land surface temperature increased, and precipitation decreased. As expected, changes in precipitation occurred primarily over the continents, especially in the northern hemisphere. Changes in the surface water balance for Africa, Australia, and South America were much less than for North American and Eurasia. Both VIC and bucket simulations of surface air temperature and precipitation were compared with gridded monthly average observation fields. These comparisons indicated that the VIC hydrology reproduced winter temperatures better, and summer temperatures worse, than the bucket model. The VIC hydrology better represented global precipitation, primarily as a result of partially reducing the upward bias in precipitation associated with the GFDL R15 bucket runs

  6. An observational and modeling study of impacts of bark beetle-caused tree mortality on surface energy and hydrological cycles

    Science.gov (United States)

    Fei Chen; Guo Zhang; Michael Barlage; Ying Zhang; Jeffrey A. Hicke; Arjan Meddens; Guangsheng Zhou; William J. Massman; John Frank

    2015-01-01

    Bark beetle outbreaks have killed billions of trees and affected millions of hectares of forest during recent decades. The objective of this study was to quantify responses of surface energy and hydrologic fluxes 2-3 yr following a spruce beetle outbreak using measurements and modeling. The authors used observations at the Rocky Mountains Glacier Lakes Ecosystem...

  7. Liquid flow along a solid surface reversibly alters interfacial chemistry.

    Science.gov (United States)

    Lis, Dan; Backus, Ellen H G; Hunger, Johannes; Parekh, Sapun H; Bonn, Mischa

    2014-06-06

    In nature, aqueous solutions often move collectively along solid surfaces (for example, raindrops falling on the ground and rivers flowing through riverbeds). However, the influence of such motion on water-surface interfacial chemistry is unclear. In this work, we combine surface-specific sum frequency generation spectroscopy and microfluidics to show that at immersed calcium fluoride and fused silica surfaces, flow leads to a reversible modification of the surface charge and subsequent realignment of the interfacial water molecules. Obtaining equivalent effects under static conditions requires a substantial change in bulk solution pH (up to 2 pH units), demonstrating the coupling between flow and chemistry. These marked flow-induced variations in interfacial chemistry should substantially affect our understanding and modeling of chemical processes at immersed surfaces. Copyright © 2014, American Association for the Advancement of Science.

  8. Modeling Surface Water Flow in the Atchafalaya Basin

    Science.gov (United States)

    Liu, K.; Simard, M.

    2017-12-01

    While most of the Mississippi River Delta is sinking due to insufficient sediment supply and subsidence, the stable wetlands and the prograding delta systems in the Atchafalaya Basin provide a unique opportunity to study the constructive interactions between riverine and marine forcings and their impacts upon coastal morphology. To better understand the hydrodynamics in this region, we developed a numerical modeling system for the water flow through the river channel - deltas - wetlands networks in the Atchafalaya Basin. Determining spatially varying model parameters for a large area composed of such diverse land cover types poses a challenge to developing an accurate numerical model. For example, the bottom friction coefficient can not be measured directly and the available elevation maps for the wetlands in the basin are inaccurate. To overcome these obstacles, we developed the modeling system in three steps. Firstly, we modeled river bathymetry based on in situ sonar transects and developed a simplified 1D model for the Wax Lake Outlet using HEC-RAS. Secondly, we used a Bayesian approach to calibrate the model automatically and infer important unknown parameters such as riverbank elevation and bottom friction coefficient through Markov Chain Monte Carlo (MCMC) simulations. We also estimated the wetland elevation based on the distribution of different vegetation species in the basin. Thirdly, with the lessons learnt from the 1D model, we developed a depth-averaged 2D model for the whole Atchafalaya Basin using Delft3D. After calibrations, the model successfully reproduced the water levels measured at five gauges in the Wax Lake Outlet and the modeled water surface profile along the channel agreed reasonably well with our LIDAR measurements. In addition, the model predicted a one-hour delay in tidal phase from the Wax Lake Delta to the upstream gauge. In summary, this project presents a procedure to initialize hydrology model parameters that integrates field

  9. Structure of peat soils and implications for biogeochemical processes and hydrological flow

    Science.gov (United States)

    Rezanezhad, F.; McCarter, C. P. R.; Gharedaghloo, B.; Kleimeier, C.; Milojevic, T.; Liu, H.; Weber, T. K. D.; Price, J. S.; Quinton, W. L.; Lenartz, B.; Van Cappellen, P.

    2017-12-01

    Permafrost peatlands contain globally important amounts of soil organic carbon and play major roles in global water, nutrient and biogeochemical cycles. The structure of peatland soils (i.e., peat) are highly complex with unique physical and hydraulic properties; where significant, and only partially reversible, shrinkage occurs during dewatering (including water table fluctuations), compression and/or decomposition. These distinct physical and hydraulic properties controls water flow, which in turn affect reactive and non-reactive solute transport (such as, sorption or degradation) and biogeochemical functions. Additionally, peat further attenuates solute migration through molecular diffusion into the inactive pores of Sphagnum dominated peat. These slow, diffusion-limited solute exchanges between the pore regions may give rise to pore-scale chemical gradients and heterogeneous distributions of microbial habitats and activity in peat soils. Permafrost peat plateaus have the same essential subsurface characteristics as other widely organic soil-covered peatlands, where the hydraulic conductivity is related to the degree of decomposition and soil compression. Increasing levels of decomposition correspond with a reduction of effective pore diameter and consequently restrict water and solute flow (by several orders of magnitude in hydraulic conductivity between the ground surface and a depth of 50 cm). In this presentation, we present the current knowledge of key physical and hydraulic properties related to the structure of globally available peat soils and discuss their implications for water storage, flow and the migration of solutes.

  10. HYDROLOGIC AND FEATURE-BASED SURFACE ANALYSIS FOR TOOL MARK INVESTIGATION ON ARCHAEOLOGICAL FINDS

    Directory of Open Access Journals (Sweden)

    K. Kovács

    2012-07-01

    Full Text Available The improvement of detailed surface documentation methods provides unique tool mark-study opportunities in the field of archaeological researches. One of these data collection techniques is short-range laser scanning, which creates a digital copy of the object’s morphological characteristics from high-resolution datasets. The aim of our work was the accurate documentation of a Bronze Age sluice box from Mitterberg, Austria with a spatial resolution of 0.2 mm. Furthermore, the investigation of the entirely preserved tool marks on the surface of this archaeological find was also accomplished by these datasets. The methodology of this tool mark-study can be summarized in the following way: At first, a local hydrologic analysis has been applied to separate the various patterns of tools on the finds’ surface. As a result, the XYZ coordinates of the special points, which represent the edge lines of the sliding tool marks, were calculated by buffer operations in a GIS environment. During the second part of the workflow, these edge points were utilized to manually clip the triangle meshes of these patterns in reverse engineering software. Finally, circle features were generated and analysed to determine the different sections along these sliding tool marks. In conclusion, the movement of the hand tool could be reproduced by the spatial analysis of the created features, since the horizontal and vertical position of the defined circle centre points indicated the various phases of the movements. This research shows an exact workflow to determine the fine morphological structures on the surface of the archaeological find.

  11. Inter-comparison of energy balance and hydrological models for land surface energy flux estimation over a whole river catchment

    DEFF Research Database (Denmark)

    Guzinski, R.; Nieto, H.; Stisen, S.

    2015-01-01

    Evapotranspiration (ET) is the main link between the natural water cycle and the land surface energy budget. Therefore water-balance and energy-balance approaches are two of the main methodologies for modelling this process. The water-balance approach is usually implemented as a complex....... The temporal patterns produced by the remote sensing and hydrological models are quite highly correlated (r ≈ 0.8). This indicates potential benefits to the hydrological modelling community of integrating spatial information derived through remote sensing methodology (contained in the ET maps...

  12. Wetland Hydrology | Science Inventory | US EPA

    Science.gov (United States)

    This chapter discusses the state of the science in wetland hydrology by touching upon the major hydraulic and hydrologic processes in these complex ecosystems, their measurement/estimation techniques, and modeling methods. It starts with the definition of wetlands, their benefits and types, and explains the role and importance of hydrology on wetland functioning. The chapter continues with the description of wetland hydrologic terms and related estimation and modeling techniques. The chapter provides a quick but valuable information regarding hydraulics of surface and subsurface flow, groundwater seepage/discharge, and modeling groundwater/surface water interactions in wetlands. Because of the aggregated effects of the wetlands at larger scales and their ecosystem services, wetland hydrology at the watershed scale is also discussed in which we elaborate on the proficiencies of some of the well-known watershed models in modeling wetland hydrology. This chapter can serve as a useful reference for eco-hydrologists, wetland researchers and decision makers as well as watershed hydrology modelers. In this chapter, the importance of hydrology for wetlands and their functional role are discussed. Wetland hydrologic terms and the major components of water budget in wetlands and how they can be estimated/modeled are also presented. Although this chapter does not provide a comprehensive coverage of wetland hydrology, it provides a quick understanding of the basic co

  13. Side Flow Effect on Surface Generation in Nano Cutting.

    Science.gov (United States)

    Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

    2017-12-01

    The side flow of material in nano cutting is one of the most important factors that deteriorate the machined surface quality. The effects of the crystallographic orientation, feed, and the cutting tool geometry, including tool edge radius, rake angle and inclination angle, on the side flow are investigated employing molecular dynamics simulation. The results show that the stagnation region is formed in front of tool edge and it is characterized by the stagnation radius R s and stagnation height h s . The side flow is formed because the material at or under the stagnation region is extruded by the tool edge to flow to the side of the tool edge. Higher stagnation height would increase the size of the side flow. The anisotropic nature of the material which partly determines the stagnation region also influences the side flow due to the different deformation mechanism under the action of the tool edge. At different cutting directions, the size of the side flow has a great difference which would finally affect the machined surface quality. The cutting directions of {100} , {110} , and {110}  are beneficial to obtain a better surface quality with small side flow. Besides that, the side flow could be suppressed by reducing the feed and optimizing the cutting tool geometry. Cutting tool with small edge radius, large positive rake angle, and inclination angle would decrease the side flow and consequently improve the machined surface quality.

  14. The impact of the Suwannee River Sill on the surface hydrology of Okefenokee Swamp, USA

    Science.gov (United States)

    Yin, Zhi-Yong; Brook, George A.

    1992-08-01

    Okefenokee Swamp, located in southeastern Georgia and northeastern Florida, is one of the largest freshwater wetland complexes and a National Wildlife Refuge in the United States. A low earthen dam, the Suwannee River Sill, was built on the largest outlet stream of Okefenokee Swamp in the early 1960s. The purpose was to raise the water level and thus reduce fire frequency in this National Wildlife Refuge. In this study, hydrologic conditions in the swamp prior to (1937-1962) and after (1963-1986) sill construction were compared by statistical procedures. An average 9 cm increase in swamp water level at the Suwannee Canal Recreation Area was attributed to the sill. Increased precipitation and decreased evapotranspiration during the study period caused another 5 cm increase in water levels. Seasonal changes in climatic factors were also responsible for seasonal changes in water levels and streamflow in the pre- and post-sill periods. Although the effect of the sill on water level was more significant during dry periods, it is doubtful that the Suwannee River Sill actually prevented occurrence of severe fibres in the post-sill period, which was wetter than the period before sill construction. The sill diverted 2.6% of swamp outflow from the Suwannee River to the St. Mary's River. Diversion of flow was more marked during low flow periods. Therefore, the discharge of the St. Mary's River in the post-sill increased more than the discharge of the Suwannee River and its variability became lower that of the Suwannee River. The relationships between swamp water level, streamflow and precipitation were also changed due to construction of the sill.

  15. On the computation of the turbulent flow near rough surface

    Science.gov (United States)

    Matveev, S. K.; Jaychibekov, N. Zh.; Shalabayeva, B. S.

    2018-05-01

    One of the problems in constructing mathematical models of turbulence is a description of the flows near a rough surface. An experimental study of such flows is also difficult because of the impossibility of measuring "inside" the roughness. The theoretical calculation is difficult because of the lack of equations describing the flow in this zone. In this paper, a new turbulence model based on the differential equation of turbulent viscosity balance was used to describe a turbulent flow near a rough surface. The difference between the new turbulence model and the previously known consists in the choice of constants and functions that determine the generation, dissipation and diffusion of viscosity.

  16. Hydrological modeling of stream flow in small Mediterranean dams and impact of climate change : case study of wadi Rmel catchment

    Science.gov (United States)

    Habaieb, Hamadi; Hermassi, Taoufik; Moncef Masmoudi, Mohamed; Ben Mechlia, Nétij

    2015-04-01

    Northern Tunisia is characterized by a semi-arid climate with an irregular and high spatial variability of rainfall. This situation is expected to aggravate under the expected increase of temperature and modification of rainfall regime predicted by most climate models for the Mediterranean region. Water is a major limiting factor for agriculture in Tunisia and mobilization of surface water resources is approaching its maximum. Dams are installed on almost all large watersheds and concerned also medium size and small ones. Hydrological functioning of such structures and their capacity to satisfy user's demand under the changing climate will be addressed using simple models and results will be discussed in this paper. The small catchment of Wadi Rmel is considered here for methodological development. This watershed (675 Km2) is situated in North-East Tunisia with average annual rainfall of 420 mm and was equipped in 1998 with a small dam. Data on rainfall collected at 12 rainfall stations during the period 1908 - 2012 are analyzed and used to build a coherent series of monthly rainfalls and spatially averaged on the watershed by the Thiessen method. In a second step, rainfall-runoff modeling was used to estimate runoff and water budget of the dam. Tow rainfall-runoff models GR2M and SWAT were considered and evaluated when using i) the rainfall observed at the dam and ii) the average rainfall on the watershed. The observed and simulated level in the dam were compared for both models and situations. Results showed that taking into account the spatial distribution of rainfall improved the simulation of stream flows and that SWAT model performs better than GR2M. The use of such models to make prediction of stream flow using downscaled climatic data from GCM will be discussed. Analysis of the results considering tow standardized sets of future greenhouse gas emissions used by the General Circulation Models for the IPCC 5th approximation RCP4.5 and RCP8.5 and three future

  17. Hydrogeologic setting, conceptual groundwater flow system, and hydrologic conditions 1995–2010 in Florida and parts of Georgia, Alabama, and South Carolina

    Science.gov (United States)

    Bellino, Jason C.; Kuniansky, Eve L.; O'Reilly, Andrew M.; Dixon, Joann F.

    2018-05-04

    The hydrogeologic setting and groundwater flow system in Florida and parts of Georgia, Alabama, and South Carolina is dominated by the highly transmissive Floridan aquifer system. This principal aquifer is a vital source of freshwater for public and domestic supply, as well as for industrial and agricultural uses throughout the southeastern United States. Population growth, increased tourism, and increased agricultural production have led to increased demand on groundwater from the Floridan aquifer system, particularly since 1950. The response of the Floridan aquifer system to these stresses often poses regional challenges for water-resource management that commonly transcend political or jurisdictional boundaries. To help water-resource managers address these regional challenges, the U.S. Geological Survey (USGS) Water Availability and Use Science Program began assessing groundwater availability of the Floridan aquifer system in 2009.The current conceptual groundwater flow system was developed for the Floridan aquifer system and adjacent systems partly on the basis of previously published USGS Regional Aquifer-System Analysis (RASA) studies, specifically many of the potentiometric maps and the modeling efforts in these studies. The Floridan aquifer system extent was divided into eight hydrogeologically distinct subregional groundwater basins delineated on the basis of the estimated predevelopment (circa 1880s) potentiometric surface: (1) Panhandle, (2) Dougherty Plain-Apalachicola, (3) Thomasville-Tallahassee, (4) Southeast Georgia-Northeast Florida-South South Carolina, (5) Suwannee, (6) West-central Florida, (7) East-central Florida, and (8) South Florida. The use of these subregions allows for a more detailed analysis of the individual basins and the groundwater flow system as a whole.The hydrologic conditions and associated groundwater budget were updated relative to previous RASA studies to include additional data collected since the 1980s and to reflect the

  18. Surface roughness effects on heat transfer in Couette flow

    International Nuclear Information System (INIS)

    Elia, G.G.

    1981-01-01

    A cell theory for viscous flow with rough surfaces is applied to two basic illustrative heat transfer problems which occur in Couette flow. Couette flow between one adiabatic surface and one isothermal surface exhibits roughness effects on the adiabatic wall temperature. Two types of rough cell adiabatic surfaces are studied: (1) perfectly insulating (the temperature gradient vanishes at the boundary of each cell); (2) average insulating (each cell may gain or lose heat but the total heat flow at the wall is zero). The results for the roughness on a surface in motion are postulated to occur because of fluid entrainment in the asperities on the moving surface. The symmetry of the roughness effects on thermal-viscous dissipation is discussed in detail. Explicit effects of the roughness on each surface, including combinations of roughness values, are presented to enable the case where the two surfaces may be from different materials to be studied. The fluid bulk temperature rise is also calculated for Couette flow with two ideal adiabatic surfaces. The effect of roughness on thermal-viscous dissipation concurs with the viscous hydrodynamic effect. The results are illustrated by an application to lubrication. (Auth.)

  19. Landfilling: Hydrology

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Beaven, R.

    2011-01-01

    Landfill hydrology deals with the presence and movement of water through a landfill. The main objective in landfill hydrology is usually to predict leachate generation, but the presence and movement of water in a landfill also affect the degradation of the waste, the leaching of pollutants...... and the geotechnical stability of the fill. Understanding landfill hydrology is thus important for many aspects of landfill, in particular siting, design and operation. The objective of this chapter is to give a basic understanding of the hydrology of landfills, and to present ways to estimate leachate quantities...... under specific circumstances. Initially a general water balance equation is defined for a typical landfill, and the different parts of the water balance are discussed. A separate section discusses water flow and the hydrogeology of landfilled wastes and considers the impact of water short...

  20. Evaluation of SCS-CN method using a fully distributed physically based coupled surface-subsurface flow model

    Science.gov (United States)

    Shokri, Ali

    2017-04-01

    The hydrological cycle contains a wide range of linked surface and subsurface flow processes. In spite of natural connections between surface water and groundwater, historically, these processes have been studied separately. The current trend in hydrological distributed physically based model development is to combine distributed surface water models with distributed subsurface flow models. This combination results in a better estimation of the temporal and spatial variability of the interaction between surface and subsurface flow. On the other hand, simple lumped models such as the Soil Conservation Service Curve Number (SCS-CN) are still quite common because of their simplicity. In spite of the popularity of the SCS-CN method, there have always been concerns about the ambiguity of the SCS-CN method in explaining physical mechanism of rainfall-runoff processes. The aim of this study is to minimize these ambiguity by establishing a method to find an equivalence of the SCS-CN solution to the DrainFlow model, which is a fully distributed physically based coupled surface-subsurface flow model. In this paper, two hypothetical v-catchment tests are designed and the direct runoff from a storm event are calculated by both SCS-CN and DrainFlow models. To find a comparable solution to runoff prediction through the SCS-CN and DrainFlow, the variance between runoff predictions by the two models are minimized by changing Curve Number (CN) and initial abstraction (Ia) values. Results of this study have led to a set of lumped model parameters (CN and Ia) for each catchment that is comparable to a set of physically based parameters including hydraulic conductivity, Manning roughness coefficient, ground surface slope, and specific storage. Considering the lack of physical interpretation in CN and Ia is often argued as a weakness of SCS-CN method, the novel method in this paper gives a physical explanation to CN and Ia.

  1. Surface hydrologic characteristics of proposed repository locations in the Palo Duro Basin of the Texas Panhandle

    International Nuclear Information System (INIS)

    1985-04-01

    This report provides a description of the surface hydrology in the two proposed locations of a high-level waste repository within the Palo Duro Basin of the Texas Panhandle. Included for consideration are the topography; the major drainage systems - Palo Duro, Tierra Blanca, and Tule Creeks, and Prairie Dog Town Fork of the Red River; and the most prominent impoundments, the playa lakes. The magnitude and frequency of precipitation throughout the region are discussed, and rainfall depth-duration-area data for the 100-year, 500-year, and probable maximum storms are presented. Soil properties are also described, with specific reference to the infiltration and runoff processes and the contribution of these processes to Ogallala aquifer recharge. A summary discussion of the local streams includes information on historical streamflow, a brief description of flooding, and results of a study of floodplains for the 100-year, 500-year, and probable maximum storms. The report concludes with a characterization of the water quality of these streams and an explanation of the local geologic influences on stream-water chemistry. 25 figures, 20 tables

  2. Hydrology and surface morphology of the Bonneville Salt Flats and Pilot Valley Playa, Utah

    Science.gov (United States)

    Lines, Gregory C.

    1979-01-01

    The Bonneville Salt Flats and Pilot Valley are in the western part of the Great Salt Lake Desert in northwest Utah. The areas are separate, though similar, hydrologic basins, and both contain a salt crust. The Bonneville salt crust covered about 40 square miles in the fall of 1976, and the salt crust in Pilot Valley covered 7 square miles. Both areas lack any noticeable surface relief (in 1976, 1.3 feet on the Bonneville salt crust and 0.3 foot on the Pilot Valley salt crust).The salt crust on the Salt Flats has been used for many years for automobile racing, and brines from shallow lacustrine deposits have been used for the production of potash. In recent years, there has been an apparent conflict between these two major uses of the area as the salt crust has diminished in both thickness and extent. Much of the Bonneville Racetrack has become rougher, and there has also been an increase in the amount of sediment on the south end of the racetrack. The Pilot Valley salt crust and surrounding playa have been largely unused.Evaporite minerals on the Salt Flats and the Pilot Valley playa are concentrated in three zones: (1) a carbonate zone composed mainly of authigenic clay-size carbonate minerals, (2) a sulfate zone composed mainly of authigenic gypsum, and (3) a chloride zone composed of crystalline halite (the salt crust). Five major types of salt crust were recognized on the Salt Flats, but only one type was observed in Pilot Valley. Geomorphic differences in the salt crust are caused by differences in their hydrologic environments. The salt crusts are dynamic features that are subject to change because of climatic factors and man's activities.Ground water occurs in three distinct aquifers in much of the western Great Salt Lake Desert: (1) the basin-fill aquifer, which yields water from conglomerate in the lower part of the basin fill, (2) the alluvial-fan aquifer, which yields water from sand and gravel along the western margins of both playas, and (3) the

  3. A comparison of hydrologic models for ecological flows and water availability

    Science.gov (United States)

    Peter V. Caldwell; Jonathan G. Kennen; Ge Sun; Julie E. Kiang; Jon B. Butcher; Michele C. Eddy; Lauren E. Hay; Jacob H. LaFontaine; Ernie F. Hain; Stacy A. C. Nelson; Steve G. McNulty

    2015-01-01

    Robust hydrologic models are needed to help manage water resources for healthy aquatic ecosystems and reliable water supplies for people, but there is a lack of comprehensive model comparison studies that quantify differences in streamflow predictions among model applications developed to answer management questions. We assessed differences in daily streamflow...

  4. Flow Structure and Surface Topology on a UCAV Planform

    Science.gov (United States)

    Elkhoury, Michel; Yavuz, Metin; Rockwell, Donald

    2003-11-01

    Flow past a X-45 UCAV planform involves the complex generation and interaction of vortices, their breakdown and occurrence of surface separation and stall. A cinema technique of high-image-density particle image velocimetry, in conjunction with dye visualization, allows characterization of the time-averaged and instantaneous states of the flow, in terms of critical points of the near-surface streamlines. These features are related to patterns of surface normal vorticity and velocity fluctuation. Spectral analysis of the naturally occurring unsteadiness of the flow allows definition of the most effective frequencies for small-amplitude perturbation of the wing, which leads to substantial alterations of the aforementioned patterns of flow structure and topology adjacent to the surface.

  5. Evaluation of Environmental Flows in Rivers Using Hydrological Methods (Case study: The Barandozchi River- Urmia Lake Basin

    Directory of Open Access Journals (Sweden)

    S. Mostafavi

    2017-01-01

    Full Text Available Introduction Development of water resources projects are accompanied by several environmental impacts, among them, the changes in the natural flow regime and the reduction of downstream water flows. With respect to the water shortages and non-uniform distribution of rainfall, sustainable management of water resources would be inevitable. In order to prevent negative effects on long-term river ecosystems, it is necessary to preserve the ecological requirements of the river systems. The assessment of environmental flow requirements in a river ecosystem is a challenging practice all over the world, and in particular, in developing countries such as Iran. Environmental requirements of rivers are often defined as a suite of flow discharges of certain magnitude, timing, frequency and duration. These flows ensure a flow regime capable of sustaining a complex set of aquatic habitats and ecosystem processes and are referred to as "environmental flows". There are several methods for determining environmental flows. The majority of these methods can be grouped into four reasonably distinct categories, namely as: hydrological, hydraulic rating, habitat simulation (or rating, and holistic methodologies. However, the current knowledge of river ecology and existing data on the needs of aquatic habitats for water quantity and quality is very limited. It is considered that there is no unique and universal method to adapt to different rivers and/or different reaches in a river. The main aim of the present study was to provide with a framework to determine environmental flow requirements of a typical perennial river using eco-hydrological methods. The Barandozchi River was selected as an important water body in the Urmia Lake Basin, Iran. The preservation of the river lives, the restoration of the internationally recognized Urmia Lake, and the elimination of negative impact from the construction of the Barandoz dam on this river were the main concerns in this

  6. Hydrology of surface waters and thermohaline circulation during the last glacial period

    International Nuclear Information System (INIS)

    Vidal, L.

    1996-01-01

    Sedimentological studies on oceanic cores from the north Atlantic have revealed, over the last glacial period, abrupt climatic changes with a periodicity of several thousand years which contrasts strongly with the glacial-interglacial periodicity (several tens of thousand years). These periods of abrupt climate changes correspond to massive icebergs discharges into the north Atlantic. The aim of this work was to study the evolution of the thermohaline circulation in relation to these episodic iceberg discharges which punctuated the last 60 ka. To reconstruct the oceanic circulation in the past, we have analysed oxygen and carbon stable isotopes on benthic foraminifera from north Atlantic deep-sea cores. First of all, the higher temporal resolution of sedimentary records has enabled us to establish a precise chrono-stratigraphy for the different cores. Then, we have shown the close linkage between surface water hydrology and deep circulation, giving evidence of the sensibility of thermohaline circulation to melt water input in the north Atlantic ocean. Indeed, changes in deep circulation are synchronous from those identified in surface waters and are recorded on a period which lasted ∼ 1500 years. Deep circulation reconstructions, before and during a typical iceberg discharge reveal several modes of circulation linked to different convection sites at the high latitudes of the Atlantic basin. Moreover, the study of the last glacial period gives the opportunity to differentiate circulation changes due to the external forcing (variations of the orbital parameters) and those linked to a more local forcing (icebergs discharges). 105 refs., 50 figs., 14 tabs., 4 appends

  7. Future Flows Climate: an ensemble of 1-km climate change projections for hydrological application in Great Britain

    Directory of Open Access Journals (Sweden)

    C. Prudhomme

    2012-11-01

    Full Text Available The dataset Future Flows Climate was developed as part of the project ''Future Flows and Groundwater Levels'' to provide a consistent set of climate change projections for the whole of Great Britain at both space and time resolutions appropriate for hydrological applications, and to enable climate change uncertainty and climate variability to be accounted for in the assessment of their possible impacts on the environment.

    Future Flows Climate is derived from the Hadley Centre's ensemble projection HadRM3-PPE that is part of the basis of UKCP09 and includes projections in available precipitation (water available to hydrological processes after snow and ice storages have been accounted for and potential evapotranspiration. It corresponds to an 11-member ensemble of transient projections from January 1950 to December 2098, each a single realisation from a different variant of HadRM3. Data are provided on a 1-km grid over the HadRM3 land areas at a daily (available precipitation and monthly (PE time step as netCDF files.

    Because systematic biases in temperature and precipitation were found between HadRM3-PPE and gridded temperature and precipitation observations for the 1962–1991 period, a monthly bias correction procedure was undertaken, based on a linear correction for temperature and a quantile-mapping correction (using the gamma distribution for precipitation followed by a spatial downscaling. Available precipitation was derived from the bias-corrected precipitation and temperature time series using a simple elevation-dependant snow-melt model. Potential evapotranspiration time series were calculated for each month using the FAO-56 Penman-Monteith equations and bias-corrected temperature, cloud cover, relative humidity and wind speed from HadRM3-PPE along with latitude of the grid and the day of the year.

    Future Flows Climate is freely available for non-commercial use under certain licensing conditions. It is the

  8. Free-surface viscous flow solution methods for ship hydrodynamics

    NARCIS (Netherlands)

    Wackers, J.; Koren, B.; Raven, H.C.; Ploeg, van der A.; Starke, A.R.; Deng, G.; Queutey, P.; Visonneau, M.; Hino, T.; Ohashi, K.

    2011-01-01

    The simulation of viscous free-surface water flow is a subject that has reached a certain maturity and is nowadays used in industrial applications, like the simulation of the flow around ships. While almost all methods used are based on the Navier-Stokes equations, the discretisation methods for the

  9. Numerical modeling of the effect of preferential flow on hillslope hydrology and slope stability

    NARCIS (Netherlands)

    Shao, W.

    2017-01-01

    The topic of this thesis is the quantification of the influence of preferential flow on landslide-triggering in potentially unstable slopes. Preferential flow paths (e.g., cracks, macropores, fissures, pipes, etc.) commonly exists in slopes. Flow velocities in preferential flow paths can be

  10. GSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)

    Science.gov (United States)

    Markstrom, Steven L.; Niswonger, Richard G.; Regan, R. Steven; Prudic, David E.; Barlow, Paul M.

    2008-01-01

    The need to assess the effects of variability in climate, biota, geology, and human activities on water availability and flow requires the development of models that couple two or more components of the hydrologic cycle. An integrated hydrologic model called GSFLOW (Ground-water and Surface-water FLOW) was developed to simulate coupled ground-water and surface-water resources. The new model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Ground-Water Flow Model (MODFLOW). Additional model components were developed, and existing components were modified, to facilitate integration of the models. Methods were developed to route flow among the PRMS Hydrologic Response Units (HRUs) and between the HRUs and the MODFLOW finite-difference cells. This report describes the organization, concepts, design, and mathematical formulation of all GSFLOW model components. An important aspect of the integrated model design is its ability to conserve water mass and to provide comprehensive water budgets for a location of interest. This report includes descriptions of how water budgets are calculated for the integrated model and for individual model components. GSFLOW provides a robust modeling system for simulating flow through the hydrologic cycle, while allowing for future enhancements to incorporate other simulation techniques.

  11. Effect of surface wettability on flow patterns in vertical gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    Nakamura, D.

    2005-01-01

    To examine the effect of the surface characteristics on the flow regime in two-phase flow, visualization study was performed using three test pipes, namely a no-coating pipe, a water-attracting coating pipe, a water-shedding coating pipe. Three flow regime maps were obtained based on the visual observation in the three pipes. In the water-attracting coating pipe, the slug flow-to-churn flow transition boundary was shifted to higher gas velocity at a given liquid velocity, whereas the churn flow-to-annular flow transition boundary was shifted to lower gas velocity at a given liquid velocity. In the water shedding coating pipe, the inverted-churn flow regime was observed in the region where the churn flow regime was to be observed in a no-coating pipe, whereas the droplet flow regime was observed in the region where the annular flow regime was to be observed in a no-coating pipe. The criteria for the slug flow-to-inverted-churn flow transition and the inverted-churn flow-to-droplet flow transition were modeled by force balance approaches. The modeled transition criteria could predict the observed flow transition boundaries reasonably well. (authors)

  12. Hydrology, Water Quality, and Surface- and Ground-Water Interactions in the Upper Hillsborough River Watershed, West-Central Florida

    Science.gov (United States)

    Trommer, J.T.; Sacks, L.A.; Kuniansky, E.L.

    2007-01-01

    A study of the Hillsborough River watershed was conducted between October 1999 through September 2003 to characterize the hydrology, water quality, and interaction between the surface and ground water in the highly karstic uppermost part of the watershed. Information such as locations of ground-water recharge and discharge, depth of the flow system interacting with the stream, and water quality in the watershed can aid in prudent water-management decisions. The upper Hillsborough River watershed covers a 220-square-mile area upstream from Hillsborough River State Park where the watershed is relatively undeveloped. The watershed contains a second order magnitude spring, many karst features, poorly drained swamps, marshes, upland flatwoods, and ridge areas. The upper Hillsborough River watershed is subdivided into two major subbasins, namely, the upper Hillsborough River subbasin, and the Blackwater Creek subbasin. The Blackwater Creek subbasin includes the Itchepackesassa Creek subbasin, which in turn includes the East Canal subbasin. The upper Hillsborough River watershed is underlain by thick sequences of carbonate rock that are covered by thin surficial deposits of unconsolidated sand and sandy clay. The clay layer is breached in many places because of the karst nature of the underlying limestone, and the highly variable degree of confinement between the Upper Floridan and surficial aquifers throughout the watershed. Potentiometric-surface maps indicate good hydraulic connection between the Upper Floridan aquifer and the Hillsborough River, and a poorer connection with Blackwater and Itchepackesassa Creeks. Similar water level elevations and fluctuations in the Upper Floridan and surficial aquifers at paired wells also indicate good hydraulic connection. Calcium was the dominant ion in ground water from all wells sampled in the watershed. Nitrate concentrations were near or below the detection limit in all except two wells that may have been affected by

  13. Analysis of energy flow during playground surface impacts.

    Science.gov (United States)

    Davidson, Peter L; Wilson, Suzanne J; Chalmers, David J; Wilson, Barry D; Eager, David; McIntosh, Andrew S

    2013-10-01

    The amount of energy dissipated away from or returned to a child falling onto a surface will influence fracture risk but is not considered in current standards for playground impact-attenuating surfaces. A two-mass rheological computer simulation was used to model energy flow within the wrist and surface during hand impact with playground surfaces, and the potential of this approach to provide insights into such impacts and predict injury risk examined. Acceleration data collected on-site from typical playground surfaces and previously obtained data from children performing an exercise involving freefalling with a fully extended arm provided input. The model identified differences in energy flow properties between playground surfaces and two potentially harmful surface characteristics: more energy was absorbed by (work done on) the wrist during both impact and rebound on rubber surfaces than on bark, and rubber surfaces started to rebound (return energy to the wrist) while the upper limb was still moving downward. Energy flow analysis thus provides information on playground surface characteristics and the impact process, and has the potential to identify fracture risks, inform the development of safer impact-attenuating surfaces, and contribute to development of new energy-based arm fracture injury criteria and tests for use in conjunction with current methods.

  14. The Influence of Slope Breaks on Lava Flow Surface Disruption

    Science.gov (United States)

    Glaze, Lori S.; Baloga, Stephen M.; Fagents, Sarah A.; Wright, Robert

    2014-01-01

    Changes in the underlying slope of a lava flow impart a significant fraction of rotational energy beyond the slope break. The eddies, circulation and vortices caused by this rotational energy can disrupt the flow surface, having a significant impact on heat loss and thus the distance the flow can travel. A basic mechanics model is used to compute the rotational energy caused by a slope change. The gain in rotational energy is deposited into an eddy of radius R whose energy is dissipated as it travels downstream. A model of eddy friction with the ambient lava is used to compute the time-rate of energy dissipation. The key parameter of the dissipation rate is shown to be rho R(sup 2/)mu, where ? is the lava density and mu is the viscosity, which can vary by orders of magnitude for different flows. The potential spatial disruption of the lava flow surface is investigated by introducing steady-state models for the main flow beyond the steepening slope break. One model applies to slow-moving flows with both gravity and pressure as the driving forces. The other model applies to fast-moving, low-viscosity, turbulent flows. These models provide the flow velocity that establishes the downstream transport distance of disrupting eddies before they dissipate. The potential influence of slope breaks is discussed in connection with field studies of lava flows from the 1801 Hualalai and 1823 Keaiwa Kilauea, Hawaii, and 2004 Etna eruptions.

  15. Application of artificial radioisotopes in hydrological studies

    International Nuclear Information System (INIS)

    Jacob, Noble; Shivanna, K.

    2009-01-01

    In this article, various applications of the artificial radioisotopes in surface water and groundwater investigations are briefly reviewed with a few recent case studies. They are found to be extremely useful in understanding the hydrological processes and obtaining pertinent parameters such as dilution factors, dispersion coefficients, rate of sediment transport in surface waters and recharge rate, velocity and flow direction in groundwater systems. (author)

  16. Dissipation of hydrological tracers and the herbicide S-metolachlor in batch and continuous-flow wetlands.

    Science.gov (United States)

    Maillard, Elodie; Lange, Jens; Schreiber, Steffi; Dollinger, Jeanne; Herbstritt, Barbara; Millet, Maurice; Imfeld, Gwenaël

    2016-02-01

    Pesticide dissipation in wetland systems with regard to hydrological conditions and operational modes is poorly known. Here, we investigated in artificial wetlands the impact of batch versus continuous-flow modes on the dissipation of the chiral herbicide S-metolachlor (S-MET) and hydrological tracers (bromide, uranine and sulforhodamine B). The wetlands received water contaminated with the commercial formulation Mercantor Gold(®) (960 g L(-1) of S-MET, 87% of the S-enantiomer). The tracer mass budget revealed that plant uptake, sorption, photo- and presumably biodegradation were prominent under batch mode (i.e. characterized by alternating oxic-anoxic conditions), in agreement with large dissipation of S-MET (90%) under batch mode. Degradation was the main dissipation pathway of S-MET in the wetlands. The degradate metolachlor oxanilic acid (MOXA) mainly formed under batch mode, whereas metolachlor ethanesulfonic acid (MESA) prevailed under continuous-flow mode, suggesting distinct degradation pathways in each wetland. R-enantiomer was preferentially degraded under batch mode, which indicated enantioselective biodegradation. The release of MESA and MOXA by the wetlands as well as the potential persistence of S-MET compared to R-MET under both oxic and anoxic conditions may be relevant for groundwater and ecotoxicological risk assessment. This study shows the effect of batch versus continuous modes on pollutant dissipation in wetlands, and that alternate biogeochemical conditions under batch mode enhance S-MET biodegradation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Daily river flow prediction based on Two-Phase Constructive Fuzzy Systems Modeling: A case of hydrological - meteorological measurements asymmetry

    Science.gov (United States)

    Bou-Fakhreddine, Bassam; Mougharbel, Imad; Faye, Alain; Abou Chakra, Sara; Pollet, Yann

    2018-03-01

    Accurate daily river flow forecast is essential in many applications of water resources such as hydropower operation, agricultural planning and flood control. This paper presents a forecasting approach to deal with a newly addressed situation where hydrological data exist for a period longer than that of meteorological data (measurements asymmetry). In fact, one of the potential solutions to resolve measurements asymmetry issue is data re-sampling. It is a matter of either considering only the hydrological data or the balanced part of the hydro-meteorological data set during the forecasting process. However, the main disadvantage is that we may lose potentially relevant information from the left-out data. In this research, the key output is a Two-Phase Constructive Fuzzy inference hybrid model that is implemented over the non re-sampled data. The introduced modeling approach must be capable of exploiting the available data efficiently with higher prediction efficiency relative to Constructive Fuzzy model trained over re-sampled data set. The study was applied to Litani River in the Bekaa Valley - Lebanon by using 4 years of rainfall and 24 years of river flow daily measurements. A Constructive Fuzzy System Model (C-FSM) and a Two-Phase Constructive Fuzzy System Model (TPC-FSM) are trained. Upon validating, the second model has shown a primarily competitive performance and accuracy with the ability to preserve a higher day-to-day variability for 1, 3 and 6 days ahead. In fact, for the longest lead period, the C-FSM and TPC-FSM were able of explaining respectively 84.6% and 86.5% of the actual river flow variation. Overall, the results indicate that TPC-FSM model has provided a better tool to capture extreme flows in the process of streamflow prediction.

  18. A Regional Model for Malaria Vector Developmental Habitats Evaluated Using Explicit, Pond-Resolving Surface Hydrology Simulations.

    Directory of Open Access Journals (Sweden)

    Ernest Ohene Asare

    Full Text Available Dynamical malaria models can relate precipitation to the availability of vector breeding sites using simple models of surface hydrology. Here, a revised scheme is developed for the VECTRI malaria model, which is evaluated alongside the default scheme using a two year simulation by HYDREMATS, a 10 metre resolution, village-scale model that explicitly simulates individual ponds. Despite the simplicity of the two VECTRI surface hydrology parametrization schemes, they can reproduce the sub-seasonal evolution of fractional water coverage. Calibration of the model parameters is required to simulate the mean pond fraction correctly. The default VECTRI model tended to overestimate water fraction in periods subject to light rainfall events and underestimate it during periods of intense rainfall. This systematic error was improved in the revised scheme by including the a parametrization for surface run-off, such that light rainfall below the initial abstraction threshold does not contribute to ponds. After calibration of the pond model, the VECTRI model was able to simulate vector densities that compared well to the detailed agent based model contained in HYDREMATS without further parameter adjustment. Substituting local rain-gauge data with satellite-retrieved precipitation gave a reasonable approximation, raising the prospects for regional malaria simulations even in data sparse regions. However, further improvements could be made if a method can be derived to calibrate the key hydrology parameters of the pond model in each grid cell location, possibly also incorporating slope and soil texture.

  19. A Regional Model for Malaria Vector Developmental Habitats Evaluated Using Explicit, Pond-Resolving Surface Hydrology Simulations.

    Science.gov (United States)

    Asare, Ernest Ohene; Tompkins, Adrian Mark; Bomblies, Arne

    2016-01-01

    Dynamical malaria models can relate precipitation to the availability of vector breeding sites using simple models of surface hydrology. Here, a revised scheme is developed for the VECTRI malaria model, which is evaluated alongside the default scheme using a two year simulation by HYDREMATS, a 10 metre resolution, village-scale model that explicitly simulates individual ponds. Despite the simplicity of the two VECTRI surface hydrology parametrization schemes, they can reproduce the sub-seasonal evolution of fractional water coverage. Calibration of the model parameters is required to simulate the mean pond fraction correctly. The default VECTRI model tended to overestimate water fraction in periods subject to light rainfall events and underestimate it during periods of intense rainfall. This systematic error was improved in the revised scheme by including the a parametrization for surface run-off, such that light rainfall below the initial abstraction threshold does not contribute to ponds. After calibration of the pond model, the VECTRI model was able to simulate vector densities that compared well to the detailed agent based model contained in HYDREMATS without further parameter adjustment. Substituting local rain-gauge data with satellite-retrieved precipitation gave a reasonable approximation, raising the prospects for regional malaria simulations even in data sparse regions. However, further improvements could be made if a method can be derived to calibrate the key hydrology parameters of the pond model in each grid cell location, possibly also incorporating slope and soil texture.

  20. Assessment of groundwater–surface water interaction using long-term hydrochemical data and isotope hydrology: Headwaters of the Condamine River, Southeast Queensland, Australia

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Jorge L., E-mail: jlmarti@ig.com.br [Queensland University of Technology, Brisbane (Australia); Raiber, Matthias [CSIRO Land and Water Flagship, Brisbane (Australia); Cox, Malcolm E. [Queensland University of Technology, Brisbane (Australia)

    2015-12-01

    A spatial analysis of hydrochemical data of groundwater and surface water was undertaken to identify groundwater-surface water connectivity in the headwaters of the Condamine River catchment, Southeast Queensland, Australia. An assessment of long-term hydrochemical and water level data supplemented by stable- and radioisotope measurements following a prolonged dry period dominated by baseflow, helped in determining patterns of interaction in different tributaries of the upper Condamine catchment. A conceptual hydrological model representing the major hydrochemical processes and their implications for stream-aquifer connectivity was developed and tested using multiple lines of evidence. The results of a multivariate statistical analysis highlight that there are two main regions with distinct hydrochemical facies (salinity, alkalinity, and predominant ions) in surface water. Geomorphology, geology, anthropogenic and climate influence were identified as the most relevant controlling factors of the spatial variability in water quality. Stable isotope data confirmed a clear evaporation trend in almost all surface water samples during baseflow conditions. Two water types can be identified and separated by the degree of evaporation and the proximity of one group to the local meteoric water line. The results confirm the discharge of groundwater from aquifers recharged by rainfall and located upstream of the surface water sampling sites. Overall, {sup 222}Rn data show a trend of increased activity in surface water towards the upstream portions of these tributaries, validating the use of this tracer to estimate groundwater input to the local creeks. The proportion of groundwater contribution to stream flow calculated by {sup 222}Rn and chloride mass balance is in agreement, and ranges between 20–70% in tributaries in the northern areas, and between 8–50% in the upper reaches of the main river channel. This study shows the efficacy of an integrated approach combining long

  1. Assessment of groundwater–surface water interaction using long-term hydrochemical data and isotope hydrology: Headwaters of the Condamine River, Southeast Queensland, Australia

    International Nuclear Information System (INIS)

    Martinez, Jorge L.; Raiber, Matthias; Cox, Malcolm E.

    2015-01-01

    A spatial analysis of hydrochemical data of groundwater and surface water was undertaken to identify groundwater-surface water connectivity in the headwaters of the Condamine River catchment, Southeast Queensland, Australia. An assessment of long-term hydrochemical and water level data supplemented by stable- and radioisotope measurements following a prolonged dry period dominated by baseflow, helped in determining patterns of interaction in different tributaries of the upper Condamine catchment. A conceptual hydrological model representing the major hydrochemical processes and their implications for stream-aquifer connectivity was developed and tested using multiple lines of evidence. The results of a multivariate statistical analysis highlight that there are two main regions with distinct hydrochemical facies (salinity, alkalinity, and predominant ions) in surface water. Geomorphology, geology, anthropogenic and climate influence were identified as the most relevant controlling factors of the spatial variability in water quality. Stable isotope data confirmed a clear evaporation trend in almost all surface water samples during baseflow conditions. Two water types can be identified and separated by the degree of evaporation and the proximity of one group to the local meteoric water line. The results confirm the discharge of groundwater from aquifers recharged by rainfall and located upstream of the surface water sampling sites. Overall, 222 Rn data show a trend of increased activity in surface water towards the upstream portions of these tributaries, validating the use of this tracer to estimate groundwater input to the local creeks. The proportion of groundwater contribution to stream flow calculated by 222 Rn and chloride mass balance is in agreement, and ranges between 20–70% in tributaries in the northern areas, and between 8–50% in the upper reaches of the main river channel. This study shows the efficacy of an integrated approach combining long

  2. Assessing the impact of model spin-up on surface water-groundwater interactions using an integrated hydrologic model

    KAUST Repository

    Ajami, Hoori

    2014-03-01

    Integrated land surface-groundwater models are valuable tools in simulating the terrestrial hydrologic cycle as a continuous system and exploring the extent of land surface-subsurface interactions from catchment to regional scales. However, the fidelity of model simulations is impacted not only by the vegetation and subsurface parameterizations, but also by the antecedent condition of model state variables, such as the initial soil moisture, depth to groundwater, and ground temperature. In land surface modeling, a given model is often run repeatedly over a single year of forcing data until it reaches an equilibrium state: the point at which there is minimal artificial drift in the model state or prognostic variables (most often the soil moisture). For more complex coupled and integrated systems, where there is an increased computational cost of simulation and the number of variables sensitive to initialization is greater than in traditional uncoupled land surface modeling schemes, the challenge is to minimize the impact of initialization while using the smallest spin-up time possible. In this study, multicriteria analysis was performed to assess the spin-up behavior of the ParFlow.CLM integrated groundwater-surface water-land surface model over a 208 km2 subcatchment of the Ringkobing Fjord catchment in Denmark. Various measures of spin-up performance were computed for model state variables such as the soil moisture and groundwater storage, as well as for diagnostic variables such as the latent and sensible heat fluxes. The impacts of initial conditions on surface water-groundwater interactions were then explored. Our analysis illustrates that the determination of an equilibrium state depends strongly on the variable and performance measure used. Choosing an improper initialization of the model can generate simulations that lead to a misinterpretation of land surface-subsurface feedback processes and result in large biases in simulated discharge. Estimated spin

  3. Local mesh refinement for incompressible fluid flow with free surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Terasaka, H.; Kajiwara, H.; Ogura, K. [Tokyo Electric Power Company (Japan)] [and others

    1995-09-01

    A new local mesh refinement (LMR) technique has been developed and applied to incompressible fluid flows with free surface boundaries. The LMR method embeds patches of fine grid in arbitrary regions of interest. Hence, more accurate solutions can be obtained with a lower number of computational cells. This method is very suitable for the simulation of free surface movements because free surface flow problems generally require a finer computational grid to obtain adequate results. By using this technique, one can place finer grids only near the surfaces, and therefore greatly reduce the total number of cells and computational costs. This paper introduces LMR3D, a three-dimensional incompressible flow analysis code. Numerical examples calculated with the code demonstrate well the advantages of the LMR method.

  4. Heat Flow In Cylindrical Bodies During Laser Surface Transformation Hardening

    Science.gov (United States)

    Sandven, Ole A.

    1980-01-01

    A mathematical model for the transient heat flow in cylindrical specimens is presented. The model predicts the temperature distribution in the vicinity of a moving ring-shaped laser spot around the periphery of the outer surface of a cylinder, or the inner surface of a hollow cylinder. It can be used to predict the depth of case in laser surface transformation hardening. The validity of the model is tested against experimental results obtained on SAE 4140 steel.

  5. Backward flow in a surface tension driven micropump

    International Nuclear Information System (INIS)

    Ju, Jongil; Park, Joong Yull; Lee, Sang-Hoon; Kim, Kyung Chun; Kim, Hyundong; Berthier, Erwin; Beebe, David J

    2008-01-01

    A surface tension driven micropump harnessing the pressure difference generated by drops of different curvature radii proves to be a simple and attractive passive method to drive fluid flow in microdevices. Here we observed the appearance of backward flow when the initial sizes of the droplets at the inlet and outlet ports are similar. To explain this phenomenon several hypotheses have been investigated. Consideration of the inertia of the fluid in the channel revealed that it alone is insufficient to explain the observed backward flow. We discovered that rotational flow inside the outlet droplet could be a source of inertia, explaining the generation of the backward flow. In addition, we have experimentally determined that the ratio of the volumes of the initial outlet drop and inlet drop correlates with the occurrence of the backward flow. (note)

  6. Core surface flow modelling from high-resolution secular variation

    DEFF Research Database (Denmark)

    Holme, R.; Olsen, Nils

    2006-01-01

    -flux hypothesis, but the spectrum of the SV implies that a conclusive test of frozen-flux is not possible. We parametrize the effects of diffusion as an expected misfit in the flow prediction due to departure from the frozen-flux hypothesis; at low spherical harmonic degrees, this contribution dominates...... the expected departure of the SV predictions from flow to the observed SV, while at high degrees the SV model uncertainty is dominant. We construct fine-scale core surface flows to model the SV. Flow non-uniqueness is a serious problem because the flows are sufficiently small scale to allow flow around non......-series of magnetic data and better parametrization of the external magnetic field....

  7. Study on surface wave characteristics of free surface flow of liquid metal lithium for IFMIF

    International Nuclear Information System (INIS)

    Hoashi, Eiji; Sugiura, Hirokazu; Yoshihashi-Suzuki, Sachiko; Yamaoka, Nobuo; Horiike, Hiroshi; Kanemura, Takuji; Kondo, Hiroo

    2011-01-01

    The international fusion materials irradiation facility (IFMIF) presents an intense neutron source to develop fusion reactor materials. The free surface flow of a liquid metal Lithium (Li) is planned as a target irradiated by two deuteron beams to generate intense neutrons and it is thus important to obtain knowledge of the surface wave characteristic for the safety and the efficiency of system in the IFMIF. We have been studying on surface wave characteristics experimentally using the liquid metal Li circulation facility at Osaka University and numerically using computational fluid dynamics (CFD) code, FLUENT. This paper reports the results of the surface fluctuation, the wave height and the surface velocity in the free surface flow of the liquid metal Li examined experimentally and numerically. In the experiment, an electro-contact probe apparatus was used to obtain the surface fluctuation and the wave height, and a high speed video was used to measure the surface velocity. We resulted in knowledge of the surface wave growth mechanism. On the other hand, a CFD simulation was also conducted to obtain information on the relation of the free surface with the inner flow. In the simulation, the model included from a two-staged contraction nozzle to a flow channel with a free surface flow region and simulation results were compared with the experimental data. (author)

  8. Assessment of the potential forecasting skill of a global hydrological model in reproducing the occurrence of monthly flow extremes

    Directory of Open Access Journals (Sweden)

    N. Candogan Yossef

    2012-11-01

    Full Text Available As an initial step in assessing the prospect of using global hydrological models (GHMs for hydrological forecasting, this study investigates the skill of the GHM PCR-GLOBWB in reproducing the occurrence of past extremes in monthly discharge on a global scale. Global terrestrial hydrology from 1958 until 2001 is simulated by forcing PCR-GLOBWB with daily meteorological data obtained by downscaling the CRU dataset to daily fields using the ERA-40 reanalysis. Simulated discharge values are compared with observed monthly streamflow records for a selection of 20 large river basins that represent all continents and a wide range of climatic zones.

    We assess model skill in three ways all of which contribute different information on the potential forecasting skill of a GHM. First, the general skill of the model in reproducing hydrographs is evaluated. Second, model skill in reproducing significantly higher and lower flows than the monthly normals is assessed in terms of skill scores used for forecasts of categorical events. Third, model skill in reproducing flood and drought events is assessed by constructing binary contingency tables for floods and droughts for each basin. The skill is then compared to that of a simple estimation of discharge from the water balance (PE.

    The results show that the model has skill in all three types of assessments. After bias correction the model skill in simulating hydrographs is improved considerably. For most basins it is higher than that of the climatology. The skill is highest in reproducing monthly anomalies. The model also has skill in reproducing floods and droughts, with a markedly higher skill in floods. The model skill far exceeds that of the water balance estimate. We conclude that the prospect for using PCR-GLOBWB for monthly and seasonal forecasting of the occurrence of hydrological extremes is positive. We argue that this conclusion applies equally to other similar GHMs and

  9. Comparing and Combining Remotely Sensed Land Surface Temperature Products for Improved Hydrological Applications

    Directory of Open Access Journals (Sweden)

    Robert M. Parinussa

    2016-02-01

    Full Text Available Land surface temperature (LST is an important variable that provides a valuable connection between the energy and water budget and is strongly linked to land surface hydrology. Space-borne remote sensing provides a consistent means for regularly observing LST using thermal infrared (TIR and passive microwave observations each with unique strengths and weaknesses. The spatial resolution of TIR based LST observations is around 1 km, a major advantage when compared to passive microwave observations (around 10 km. However, a major advantage of passive microwaves is their cloud penetrating capability making them all-weather sensors whereas TIR observations are routinely masked under the presence of clouds and aerosols. In this study, a relatively simple combination approach that benefits from the cloud penetrating capacity of passive microwave sensors was proposed. In the first step, TIR and passive microwave LST products were compared over Australia for both anomalies and raw timeseries. A very high agreement was shown over the vast majority of the country with R2 typically ranging from 0.50 to 0.75 for the anomalies and from 0.80 to 1.00 for the raw timeseries. Then, the scalability of the passive microwave based LST product was examined and a pixel based merging approach through linear scaling was proposed. The individual and merged LST products were further compared against independent LST from the re-analysis model outputs. This comparison revealed that the TIR based LST product agrees best with the re-analysis data (R2 0.26 for anomalies and R2 0.76 for raw data, followed by the passive microwave LST product (R2 0.16 for anomalies and R2 0.66 for raw data and the combined LST product (R2 0.18 for anomalies and R2 0.62 for raw data. It should be noted that the drop in performance comes with an increased revisit frequency of approximately 20% compared to the revised frequency of the TIR alone. Additionally, this comparison against re

  10. A coupled mechanical-hydrological methodology for modeling flow in jointed rock masses using laboratory data for the joint flow model

    International Nuclear Information System (INIS)

    Voss, C.F.; Bastian, R.J.; Shotwell, L.R.

    1986-01-01

    Pacific Northwest Laboratory (PNL) currently supports the U.S. Department of Energy's Office of Civilian Radioactive Waste Management in developing and evaluating analytical methods for assessing the suitability of sites for geologic disposal of high-level radioactive waste. The research includes consideration of hydrological, geomechanical, geochemical, and waste package components and the evaluation of the degree of coupling that can occur between two or more of these components. The PNL effort and those of other research groups investing potential waste sites in the U.S. and abroad are producing a suite of computer codes to analyze the long-term performance of the proposed repository sites. This paper summarizes the ongoing research in rock mechanics at PNL involving flow through jointed rock. The objective of this research is to develop a methodology for modeling the coupled mechanical-hydrological process of flow through joints and then attempt to validate a ''simple'' model using small-scale laboratory test data as a basis for judging whether the approach has merit. This paper discusses the laboratory tests being conducted to develop a joint behavioral constitutive model for the numerical method under development and the modeling approach being considered

  11. Measurements of the near-surface flow over a hill

    Science.gov (United States)

    Vosper, S. B.; Mobbs, S. D.; Gardiner, B. A.

    2002-10-01

    The near-surface flow over a hill with moderate slope and height comparable with the boundary-layer depth is investigated through field measurements of the mean flow (at 2 m), surface pressure, and turbulent momentum flux divergence between 8 and 15 m. The measurements were made along an east-west transect across the hill Tighvein (height 458 m, approximate width 8 km) on the Isle of Arran, south-west Scotland, during two separate periods, each of around three-weeks duration. Radiosonde ascents are used to determine the variation of a Froude number, FL = U/NL, where U is the wind speed at the middle-layer height, hm, N is the mean Brunt-Väisälä frequency below this height and L is a hill length-scale. Measurements show that for moderately stratified flows (for which FL 0.25) a minimum in the hill-induced surface-pressure perturbation occurs across the summit and this is accompanied by a maximum in the near-surface wind speed. In the more strongly stratified case (FL 0.25) the pressure field is more asymmetric and the lee-slope flow is generally stronger than on the windward slope. Such a flow pattern is qualitatively consistent with that predicted by stratified linear boundary-layer and gravity-wave theories. The near-surface momentum budget is analysed by evaluating the dominant terms in a Bernoulli equation suitable for turbulent flow. Measurements during periods of westerly flow are used to evaluate the dominant terms, and the equation is shown to hold to a reasonable approximation on the upwind slope of the hill and also on the downwind slope, away from the summit. Immediately downwind of the summit, however, the Bernoulli equation does not hold. Possible reasons for this, such as non-separated sheltering and flow separation, are discussed.

  12. Development of hydrological models and surface process modelization Study case in High Mountain slopes

    International Nuclear Information System (INIS)

    Loaiza, Juan Carlos; Pauwels, Valentijn R

    2011-01-01

    Hydrological models are useful because allow to predict fluxes into the hydrological systems, which is useful to predict foods and violent phenomenon associated to water fluxes, especially in materials under a high meteorization level. The combination of these models with meteorological predictions, especially with rainfall models, allow to model water behavior into the soil. On most of cases, this type of models is really sensible to evapotranspiration. On climatic studies, the superficial processes have to be represented adequately. Calibration and validation of these models is necessary to obtain reliable results. This paper is a practical exercise of application of complete hydrological information at detailed scale in a high mountain catchment, considering the soil use and types more representatives. The information of soil moisture, infiltration, runoff and rainfall is used to calibrate and validate TOPLATS hydrological model to simulate the behavior of soil moisture. The finds show that is possible to implement an hydrological model by means of soil moisture information use and an equation of calibration by Extended Kalman Filter (EKF).

  13. Tidally-driven Surface Flow in a Georgia Estuarine Saltmarsh

    Science.gov (United States)

    Young, D.; Bruder, B. L.; Haas, K. A.; Webster, D. R.

    2016-02-01

    Estuarine saltmarshes are diverse, valuable, and productive ecosystems. Vegetation dampens wave and current energy, thereby allowing the estuaries to serve as a nursery habitat for shellfish and fish species. Tidally-driven flow transports nutrients into and out of the estuary, nourishing inshore and offshore vegetation and animals. The effects of vegetation on the marsh hydrodynamics and on the estuary creek and channel flow are, unfortunately, poorly understood, and the knowledge that does exist primarily originates from modeling studies. Field studies addressing marsh surface flows are limited due to the difficulty of accurately measuring the water surface elevation and acquiring concurrent velocity measurements in the dense marsh vegetation. This study partially bridges the gap between the model observations of marsh flow driven by water surface elevation gradients and flume studies of flow through vegetation. Three current meters and three pressure transducers were deployed for three days along a transect perpendicular to the main channel (Little Ogeechee River) in a saltmarsh adjacent to Rose Dhu Island (Savannah, Georgia, USA). The pressure transducer locations were surveyed daily with static GPS yielding highly accurate water surface elevation data. During flood and ebb tide, water surface elevation differences between the marsh and Little Ogeechee River were observed up to 15 cm and pressure gradients were observed up to 0.0017 m of water surface elevation drop per m of linear distance. The resulting channel-to-saltmarsh pressure gradients substantially affected tidal currents at all current meters. At one current meter, the velocity was nearly perpendicular to the Little Ogeechee River bank. The velocity at this location was effectively modeled as a balance between the pressure gradient and marsh vegetation-induced drag force using the Darcy-Weisbach/Lindner's equations developed for flow-through-vegetation analysis in open channel flow.

  14. Hydrological Modelling and data assimilation of Satellite Snow Cover Area using a Land Surface Model, VIC

    Directory of Open Access Journals (Sweden)

    S. Naha

    2016-06-01

    Full Text Available The snow cover plays an important role in Himalayan region as it contributes a useful amount to the river discharge. So, besides estimating rainfall runoff, proper assessment of snowmelt runoff for efficient management and water resources planning is also required. A Land Surface Model, VIC (Variable Infiltration Capacity is used at a high resolution grid size of 1 km. Beas river basin up to Thalot in North West Himalayas (NWH have been selected as the study area. At first model setup is done and VIC has been run in its energy balance mode. The fluxes obtained from VIC has been routed to simulate the discharge for the time period of (2003-2006. Data Assimilation is done for the year 2006 and the techniques of Data Assimilation considered in this study are Direct Insertion (D.I and Ensemble Kalman Filter (EnKF that uses observations of snow covered area (SCA to update hydrologic model states. The meteorological forcings were taken from 0.5 deg. resolution VIC global forcing data from 1979-2006 with daily maximum temperature, minimum temperature from Climate Research unit (CRU, rainfall from daily variability of NCEP and wind speed from NCEP-NCAR analysis as main inputs and Indian Meteorological Department (IMD data of 0.25 °. NBSSLUP soil map and land use land cover map of ISRO-GBP project for year 2014 were used for generating the soil parameters and vegetation parameters respectively. The threshold temperature i.e. the minimum rain temperature is -0.5°C and maximum snow temperature is about +0.5°C at which VIC can generate snow fluxes. Hydrological simulations were done using both NCEP and IMD based meteorological Forcing datasets, but very few snow fluxes were obtained using IMD data met forcing, whereas NCEP based met forcing has given significantly better snow fluxes throughout the simulation years as the temperature resolution as given by IMD data is 0.5°C and rainfall resolution of 0.25°C. The simulated discharge has been validated

  15. Hydraulic investigation on free surface flow of windowless target

    International Nuclear Information System (INIS)

    Hu Chen; Gu Hanyang

    2015-01-01

    The formation and control of free surface are the most essential parts in the studies of windowless target in ACCELERATOR-DRIVEN sub-critical system (ADS). Water model experiments and 360° full scale three dimensional simulations were conducted. The experimental study demonstrates that the free surface is significantly affected by the inlet flow velocity and outlet pressure. The length of free surface decreases in the second order with the increase of inlet flow velocity, while it decreases linearly with the outlet pressure. The structure and feature of flow field were investigated. The results show that the free surface is vulnerable to the vortex movement. Transient simulations were performed with volume of fluid (VOF) method, large eddy simulation (LES) and the pressure implicit with splitting of operators (PISO) algorithm. The simulation results agree qualitatively well with the experimental data related to both free surface flow and flow field. These simulation models and methods are proved to be applicable in the hydraulic simulations of liquid heavy metal target. (authors)

  16. Application of the MacCormack scheme to overland flow routing for high-spatial resolution distributed hydrological model

    Science.gov (United States)

    Zhang, Ling; Nan, Zhuotong; Liang, Xu; Xu, Yi; Hernández, Felipe; Li, Lianxia

    2018-03-01

    Although process-based distributed hydrological models (PDHMs) are evolving rapidly over the last few decades, their extensive applications are still challenged by the computational expenses. This study attempted, for the first time, to apply the numerically efficient MacCormack algorithm to overland flow routing in a representative high-spatial resolution PDHM, i.e., the distributed hydrology-soil-vegetation model (DHSVM), in order to improve its computational efficiency. The analytical verification indicates that both the semi and full versions of the MacCormack schemes exhibit robust numerical stability and are more computationally efficient than the conventional explicit linear scheme. The full-version outperforms the semi-version in terms of simulation accuracy when a same time step is adopted. The semi-MacCormack scheme was implemented into DHSVM (version 3.1.2) to solve the kinematic wave equations for overland flow routing. The performance and practicality of the enhanced DHSVM-MacCormack model was assessed by performing two groups of modeling experiments in the Mercer Creek watershed, a small urban catchment near Bellevue, Washington. The experiments show that DHSVM-MacCormack can considerably improve the computational efficiency without compromising the simulation accuracy of the original DHSVM model. More specifically, with the same computational environment and model settings, the computational time required by DHSVM-MacCormack can be reduced to several dozen minutes for a simulation period of three months (in contrast with one day and a half by the original DHSVM model) without noticeable sacrifice of the accuracy. The MacCormack scheme proves to be applicable to overland flow routing in DHSVM, which implies that it can be coupled into other PHDMs for watershed routing to either significantly improve their computational efficiency or to make the kinematic wave routing for high resolution modeling computational feasible.

  17. Instability of flow of liquid film over a heated surface

    International Nuclear Information System (INIS)

    Sha, W.T.

    1994-01-01

    Fundamental concepts and basic equations of a flowing thin liquid film cooling a heated surfaced by its vaporization and the effect of dry patches were treated. Stable film flow prior to the appearance of dry patches on the heated surface is maintained by a balance of various forces due to surface tension, shear stress, heat and mass transfer, and gravity. Film splitting at a critical film thickness produces dry patches due to perturbation by waves on a perfect surface, and often by surface imperfection and uneven heating. This work is primarily motivated by the design of next-generation nuclear reactors, which employ many novel passive heat-removal systems via natural circulation. These systems are design to prevent damage to the reactor core and containment without action by the reactor operators during or after a design basis accident such as a loss of coolant accident (LOCA) or a main steam-line break (MSLB) accident

  18. Calculation of the Instream Ecological Flow of the Wei River Based on Hydrological Variation

    Directory of Open Access Journals (Sweden)

    Shengzhi Huang

    2014-01-01

    Full Text Available It is of great significance for the watershed management department to reasonably allocate water resources and ensure the sustainable development of river ecosystems. The greatly important issue is to accurately calculate instream ecological flow. In order to precisely compute instream ecological flow, flow variation is taken into account in this study. Moreover, the heuristic segmentation algorithm that is suitable to detect the mutation points of flow series is employed to identify the change points. Besides, based on the law of tolerance and ecological adaptation theory, the maximum instream ecological flow is calculated, which is the highest frequency of the monthly flow based on the GEV distribution and very suitable for healthy development of the river ecosystems. Furthermore, in order to guarantee the sustainable development of river ecosystems under some bad circumstances, minimum instream ecological flow is calculated by a modified Tennant method which is improved by replacing the average flow with the highest frequency of flow. Since the modified Tennant method is more suitable to reflect the law of flow, it has physical significance, and the calculation results are more reasonable.

  19. Using ATM laser altimetry to constrain surface mass balance estimates and supraglacial hydrology of the Greenland Ice Sheet

    Science.gov (United States)

    Studinger, M.; Medley, B.; Manizade, S.; Linkswiler, M. A.

    2016-12-01

    Repeat airborne laser altimetry measurements can provide large-scale field observations to better quantify spatial and temporal variability of surface processes contributing to seasonal elevation change and therefore surface mass balance. As part of NASA's Operation IceBridge the Airborne Topographic Mapper (ATM) laser altimeter measured the surface elevation of the Greenland Ice Sheet during spring (March - May) and fall (September - October) of 2015. Comparison of the two surveys reveals a general trend of thinning for outlet glaciers and for the ice sheet in a manner related to elevation and latitude. In contrast, some thickening is observed on the west (but not on the east) side of the ice divide above 2200 m elevation in the southern half, below latitude 69°N.The observed magnitude and spatial patterns of the summer melt signal can be utilized as input into ice sheet models and for validating reanalysis of regional climate models such as RACMO and MAR. We use seasonal anomalies in MERRA-2 climate fields (temperature, precipitation) to understand the observed spatial signal in seasonal change. Aside from surface elevation change, runoff from meltwater pooling in supraglacial lakes and meltwater channels accounts for at least half of the total mass loss. The ability of the ATM laser altimeters to image glacial hydrological features in 3-D and determine the depth of supraglacial lakes could be used for process studies and for quantifying melt processes over large scales. The 1-meter footprint diameter of ATM laser on the surface, together with a high shot density, allows for the production of large-scale, high-resolution, geodetic quality DEMs (50 x 50 cm) suitable for fine-scale glacial hydrology research and as input to hydrological models quantifying runoff.

  20. Estimating daily time series of streamflow using hydrological model calibrated based on satellite observations of river water surface width: Toward real world applications.

    Science.gov (United States)

    Sun, Wenchao; Ishidaira, Hiroshi; Bastola, Satish; Yu, Jingshan

    2015-05-01

    Lacking observation data for calibration constrains applications of hydrological models to estimate daily time series of streamflow. Recent improvements in remote sensing enable detection of river water-surface width from satellite observations, making possible the tracking of streamflow from space. In this study, a method calibrating hydrological models using river width derived from remote sensing is demonstrated through application to the ungauged Irrawaddy Basin in Myanmar. Generalized likelihood uncertainty estimation (GLUE) is selected as a tool for automatic calibration and uncertainty analysis. Of 50,000 randomly generated parameter sets, 997 are identified as behavioral, based on comparing model simulation with satellite observations. The uncertainty band of streamflow simulation can span most of 10-year average monthly observed streamflow for moderate and high flow conditions. Nash-Sutcliffe efficiency is 95.7% for the simulated streamflow at the 50% quantile. These results indicate that application to the target basin is generally successful. Beyond evaluating the method in a basin lacking streamflow data, difficulties and possible solutions for applications in the real world are addressed to promote future use of the proposed method in more ungauged basins. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Long-term flow rates and biomat zone hydrology in soil columns receiving septic tank effluent.

    Science.gov (United States)

    Beal, C D; Gardner, E A; Kirchhof, G; Menzies, N W

    2006-07-01

    Soil absorption systems (SAS) are used commonly to treat and disperse septic tank effluent (STE). SAS can hydraulically fail as a result of the low permeable biomat zone that develops on the infiltrative surface. The objectives of this experiment were to compare the hydraulic properties of biomats grown in soils of different textures, to investigate the long-term acceptance rates (LTAR) from prolonged application of STE, and to assess if soils were of major importance in determining LTAR. The STE was applied to repacked sand, Oxisol and Vertisol soil columns over a period of 16 months, at equivalent hydraulic loading rates of 50, 35 and 8L/m(2)/d, respectively. Infiltration rates, soil matric potentials, and biomat hydraulic properties were measured either directly from the soil columns or calculated using established soil physics theory. Biomats 1 to 2 cm thick developed in all soils columns with hydraulic resistances of 27 to 39 d. These biomats reduced a 4 order of magnitude variation in saturated hydraulic conductivity (K(s)) between the soils to a one order of magnitude variation in LTAR. A relationship between biomat resistance and organic loading rate was observed in all soils. Saturated hydraulic conductivity influenced the rate and extent of biomat development. However, once the biomat was established, the LTAR was governed by the resistance of the biomat and the sub-biomat soil unsaturated flow regime induced by the biomat. Results show that whilst initial soil K(s) is likely to be important in the establishment of the biomat zone in a trench, LTAR is determined by the biomat resistance and the unsaturated soil hydraulic conductivity, not the K(s) of a soil. The results call into question the commonly used approach of basing the LTAR, and ultimately trench length in SAS, on the initial K(s) of soils.

  2. Understand the impacts of wetland restoration on peak flow and baseflow by coupling hydrologic and hydrodynamic models

    Science.gov (United States)

    Gao, H.; Sabo, J. L.

    2016-12-01

    Wetlands as the earth's kidneys provides various ecosystem services, such as absorbing pollutants, purifying freshwater, providing habitats for diverse ecosystems, sustaining species richness and biodiversity. From hydrologic perspective, wetlands can store storm-flood water in flooding seasons and release it afterwards, which will reduce flood peaks and reshape hydrograph. Therefore, as a green infrastructure and natural capital, wetlands provides a competent alternative to manage water resources in a green way, with potential to replace the widely criticized traditional gray infrastructure (i.e. dams and dikes) in certain cases. However, there are few systematic scientific tools to support our decision-making on site selection and allow us to quantitatively investigate the impacts of restored wetlands on hydrological process, not only in local scale but also in the view of entire catchment. In this study, we employed a topographic index, HAND (the Height Above the Nearest Drainage), to support our decision on potential site selection. Subsequently, a hydrological model (VIC, Variable Infiltration Capacity) was coupled with a macro-scale hydrodynamic model (CaMa-Flood, Catchment-Based Macro-scale Floodplain) to simulate the impact of wetland restoration on flood peaks and baseflow. The results demonstrated that topographic information is an essential factor to select wetland restoration location. Different reaches, wetlands area and the change of roughness coefficient should be taken into account while evaluating the impacts of wetland restoration. The simulated results also clearly illustrated that wetland restoration will increase the local storage and decrease the downstream peak flow which is beneficial for flood prevention. However, its impact on baseflow is ambiguous. Theoretically, restored wetlands will increase the baseflow due to the slower release of the stored flood water, but the increase of wetlands area may also increase the actual evaporation

  3. Fluid flow near the surface of earth's outer core

    Science.gov (United States)

    Bloxham, Jeremy; Jackson, Andrew

    1991-01-01

    This review examines the recent attempts at extracting information on the pattern of fluid flow near the surface of the outer core from the geomagnetic secular variation. Maps of the fluid flow at the core surface are important as they may provide some insight into the process of the geodynamo and may place useful constraints on geodynamo models. In contrast to the case of mantle convection, only very small lateral variations in core density are necessary to drive the flow; these density variations are, by several orders of magnitude, too small to be imaged seismically; therefore, the geomagnetic secular variation is utilized to infer the flow. As substantial differences exist between maps developed by different researchers, the possible underlying reasons for these differences are examined with particular attention given to the inherent problems of nonuniqueness.

  4. A model for estimating time-variant rainfall infiltration as a function of antecedent surface moisture and hydrologic soil type

    Science.gov (United States)

    Wilkening, H. A.; Ragan, R. M.

    1982-01-01

    Recent research indicates that the use of remote sensing techniques for the measurement of near surface soil moisture could be practical in the not too distant future. Other research shows that infiltration rates, especially for average or frequent rainfall events, are extremely sensitive to the proper definition and consideration of the role of the soil moisture at the beginning of the rainfall. Thus, it is important that an easy to use, but theoretically sound, rainfall infiltration model be available if the anticipated remotely sensed soil moisture data is to be optimally utilized for hydrologic simulation. A series of numerical experiments with the Richards' equation for an array of conditions anticipated in watershed hydrology were used to develop functional relationships that describe temporal infiltration rates as a function of soil type and initial moisture conditions.

  5. Hydrological model calibration for flood prediction in current and future climates using probability distributions of observed peak flows and model based rainfall

    Science.gov (United States)

    Haberlandt, Uwe; Wallner, Markus; Radtke, Imke

    2013-04-01

    Derived flood frequency analysis based on continuous hydrological modelling is very demanding regarding the required length and temporal resolution of precipitation input data. Often such flood predictions are obtained using long precipitation time series from stochastic approaches or from regional climate models as input. However, the calibration of the hydrological model is usually done using short time series of observed data. This inconsistent employment of different data types for calibration and application of a hydrological model increases its uncertainty. Here, it is proposed to calibrate a hydrological model directly on probability distributions of observed peak flows using model based rainfall in line with its later application. Two examples are given to illustrate the idea. The first one deals with classical derived flood frequency analysis using input data from an hourly stochastic rainfall model. The second one concerns a climate impact analysis using hourly precipitation from a regional climate model. The results show that: (I) the same type of precipitation input data should be used for calibration and application of the hydrological model, (II) a model calibrated on extreme conditions works quite well for average conditions but not vice versa, (III) the calibration of the hydrological model using regional climate model data works as an implicit bias correction method and (IV) the best performance for flood estimation is usually obtained when model based precipitation and observed probability distribution of peak flows are used for model calibration.

  6. Dynamic surface-pressure instrumentation for rods in parallel flow

    International Nuclear Information System (INIS)

    Mulcahy, T.M.; Lawrence, W.

    1979-01-01

    Methods employed and experience gained in measuring random fluid boundary layer pressures on the surface of a small diameter cylindrical rod subject to dense, nonhomogeneous, turbulent, parallel flow in a relatively noise-contaminated flow loop are described. Emphasis is placed on identification of instrumentation problems; description of transducer construction, mounting, and waterproofing; and the pretest calibration required to achieve instrumentation capable of reliable data acquisition

  7. Dynamics and Instabilities of Free Surface and Vortex Flows

    DEFF Research Database (Denmark)

    Tophøj, Laust Emil Hjerrild

    2012-01-01

    This PhD thesis consists of two main parts. The first part describes the dynamics of an ideal fluid on a stationary free surface of a given shape. It turns out that one can formulate a set of self-contained equations of momentum conservation for the tangential flow, with no reference to the flow ......)]. Finally, an experimental work on elastic collisions of wet spheres is briefly discussed....

  8. Hydrological analysis relevant to surface water storage at Jabiluka. Supervising Scientist report 142

    International Nuclear Information System (INIS)

    Chiew, F.H.S.; Wang, Q.J.

    1999-01-01

    The report is prepared for the Supervising Scientist at Jabiru. It describes part of an investigation into hydrological issues relating to the water management system proposed for the Jabiluka project. Specifically, the objective is to estimate the water storage capacity required to store surface runoff and other water within the total containment zone (TCZ) of the Jabiluka project. The water storage volume is calculated for a range of probabilities up to 0.002% that the pond design volume would be exceeded over a 30-year mine life. In this study, 50 000 sets of 30 years of daily rainfall and monthly pan evaporation data are stochastically generated to simulate the storage water balance. The approach used by Kinhill and Energy Resources of Australia (ERA) is reviewed and the pond design compared with the estimates derived here. The Kinhill-ERA approach is described in the Jabiluka Mill Alternative Public Environment Report and the Jabiluka Mill Alternative Public Environment Report Technical Appendices (hereon referred to as Jabiluka PER Appendices) (1998). The two reports also provide background to many other issues. The structural design of the storage and other features of the mine site are not considered here. This study also assumes that the bunds and other drainage diversion structures will prevent all water outside the TCZ from entering the TCZ and vice versa. The storage water balance components are discussed in section 2. Some of the water inflows into the storage and losses from the storage are discussed in detail, while elsewhere, the values used by Kinhill-ERA are adopted. Section 3 describes the selection of the climate stations used here, the rainfall and pan evaporation characteristics in the area and the stochastic generation of 1.5 million years of daily rainfall and monthly pan evaporation data. Section 4 describes the approach used to estimate the storage capacity, and presents the storage capacity estimates for various probabilities of

  9. Radionuclide transfer onto ground surface in surface water flow. 2. Undisturbed tuff rock

    International Nuclear Information System (INIS)

    Mukai, Masayuki; Takebe, Shinichi; Komiya, Tomokazu

    1994-09-01

    Radionuclide migration with ground surface water flow is considered to be one of path ways in the scenario for environmental migration of the radionuclide leaked from LLRW depository. To study the radionuclide migration demonstratively, a ground surface radionuclide migration test was carried out by simulating radioactive solution flowing on the sloped tuff rock surface. Tuff rock sample of 240 cm in length taken from the Shimokita district was used to test the transfer of 60 Co, 85 Sr and 137 Cs onto the sample surface from the flowing radioactive solution under restricted infiltration condition at flow rates of 25, 80, 160ml/min and duration of 56h. The concentration change of the radionuclides in effluent was nearly constant as a function of elapsed time during the experimental period, but decreased with lower flow rates. Among the three radionuclides, 137 Cs was greatly decreased its concentration to 30% of the inflow. Adsorbed distribution of the radionuclides concentration on the ground surface decreased gradually with the distance from the inlet, and showed greater gradient at lower flow rate. Analyzing the result by the migration model, where a vertical advection distribution and two-dimensional diffusion in surface water are adopted with a first order adsorption reaction, value of migration parameters was obtained relating to the radionuclide adsorption and the surface water flow, and the measured distribution could be well simulated by adopting the value to the model. By comparing the values with the case of loamy soil layer, all values of the migration parameters showed not so great difference between two samples for 60 Co and 85 Sr. For 137 Cs, reflecting a few larger value of adsorption to the tuff rock, larger ability to reduce the concentration of flowing radioactive solution could be indicated than that to the loamy soil surface by estimation for long flowed distance. (author)

  10. Near-surface flow of volcanic gases on Io

    International Nuclear Information System (INIS)

    Lee, S.W.; Thomas, P.C.

    1980-01-01

    Significant near-surface flow of gas several hundred kilometers from Pele (Plume 1) on Io is indicated by a series of bright, elongate albedo markings. Particles produced at small, local vents are apparently carried as much as 70 km farther 'downwind' from Pele. The gas densities and velocities necessary to suspend 0.1 to 10 micron particles at such a distance imply mass flow rates of 10 to the 7th - 10 to the 9th g/sec. Such flow rates are consistent with other estimates of mass transport by the plume. The large flow rates so far from the source allow an estimate of the rate of resurfacing of Io by lava flows and pyroclastics that is independent of estimates based on meteorite flux or on the amount of solids carried within the plumes themselves

  11. Flow of viscous fluid along an exponentially stretching curved surface

    Directory of Open Access Journals (Sweden)

    N.F. Okechi

    Full Text Available In this paper, we present the boundary layer analysis of flow induced by rapidly stretching curved surface with exponential velocity. The governing boundary value problem is reduced into self-similar form using a new similarity transformation. The resulting equations are solved numerically using shooting and Runge-Kutta methods. The numerical results depicts that the fluid velocity as well as the skin friction coefficient increases with the surface curvature, similar trend is also observed for the pressure. The dimensionless wall shear stress defined for this problem is greater than that of a linearly stretching curved surface, but becomes comparably less for a surface stretching with a power-law velocity. In addition, the result for the plane surface is a special case of this study when the radius of curvature of the surface is sufficiently large. The numerical investigations presented in terms of the graphs are interpreted with the help of underlying physics of the fluid flow and the consequences arising from the curved geometry. Keywords: Boundary layer flow, Curved surface, Exponential stretching, Curvature

  12. Flow profiling of a surface-acoustic-wave nanopump

    Science.gov (United States)

    Guttenberg, Z.; Rathgeber, A.; Keller, S.; Rädler, J. O.; Wixforth, A.; Kostur, M.; Schindler, M.; Talkner, P.

    2004-11-01

    The flow profile in a capillary gap and the pumping efficiency of an acoustic micropump employing surface acoustic waves is investigated both experimentally and theoretically. Ultrasonic surface waves on a piezoelectric substrate strongly couple to a thin liquid layer and generate a quadrupolar streaming pattern within the fluid. We use fluorescence correlation spectroscopy and fluorescence microscopy as complementary tools to investigate the resulting flow profile. The velocity was found to depend on the applied power approximately linearly and to decrease with the inverse third power of the distance from the ultrasound generator on the chip. The found properties reveal acoustic streaming as a promising tool for the controlled agitation during microarray hybridization.

  13. An evaluation of the hydrologic relevance of lateral flow in snow at hillslope and catchment scales

    Science.gov (United States)

    David Eiriksson; Michael Whitson; Charles H. Luce; Hans Peter Marshall; John Bradford; Shawn G. Benner; Thomas Black; Hank Hetrick; James P. McNamara

    2013-01-01

    Lateral downslope flow in snow during snowmelt and rain-on-snow (ROS) events is a well-known phenomenon, yet its relevance to water redistribution at hillslope and catchment scales is not well understood. We used dye tracers, geophysical methods, and hydrometric measurements to describe the snow properties that promote lateral flow, assess the relative velocities of...

  14. Hydrologic connectivity between geographically isolated wetlands and surface water systems: A review of select modeling methods

    Science.gov (United States)

    Heather E. Golden; Charles R. Lane; Devendra M. Amatya; Karl W. Bandilla; Hadas Raanan Kiperwas Kiperwas; Christopher D. Knightes; Herbert. Ssegane

    2014-01-01

    Geographically isolated wetlands (GIW), depressional landscape features entirely surrounded by upland areas, provide a wide range of ecological functions and ecosystem services for human well-being. Current and future ecosystem management and decision-making rely on a solid scientific understanding of how hydrologic processes affect these important GIW services and...

  15. Representing Northern Peatland Hydrology and Biogeochemistry with ALM Land Surface Model

    Science.gov (United States)

    Shi, X.; Ricciuto, D. M.; Thornton, P. E.; Hanson, P. J.; Xu, X.; Mao, J.; Warren, J.; Yuan, F.; Norby, R. J.; Sebestyen, S.; Griffiths, N.; Weston, D. J.; Walker, A.

    2017-12-01

    Northern peatlands are likely to be important in future carbon cycle-climate feedbacks due to their large carbon pool and vulnerability to hydrological change. Predictive understanding of northern peatland hydrology is a necessary precursor to understanding the fate of massive carbon stores in these systems under the influence of present and future climate change. Current models have begun to address microtopographic controls on peatland hydrology, but none have included a prognostic calculation of peatland water table depth for a vegetated wetland, independent of prescribed regional water tables. Firstly, we introduce a new configuration of the land model (ALM) of Accelerated Climate model for Energy (ACME), which includes a fully prognostic water table calculation for a vegetated peatland. Secondly, we couple our new hydrology treatment with vertically structured soil organic matter pool, and the addition of components from methane biogeochemistry. Thirdly, we introduce a new PFT for mosses and implement the water content dynamics and physiology of mosses. We inform and test our model based on SPRUCE experiment to get the reasonable results for the seasonal dynamics water table depths, water content dynamics and physiology of mosses, and correct soil carbon profiles. Then, we use our new model structure to test the how the water table depth and CH4 emission will respond to elevated CO2 and different warming scenarios.

  16. Biomolecular Nano-Flow-Sensor to Measure Near-Surface Flow

    Directory of Open Access Journals (Sweden)

    Noji Hiroyuki

    2009-01-01

    Full Text Available Abstract We have proposed and experimentally demonstrated that the measurement of the near-surface flow at the interface between a liquid and solid using a 10 nm-sized biomolecular motor of F1-ATPase as a nano-flow-sensor. For this purpose, we developed a microfluidic test-bed chip to precisely control the liquid flow acting on the F1-ATPase. In order to visualize the rotation of F1-ATPase, several hundreds nanometer-sized particle was immobilized at the rotational axis of F1-ATPase to enhance the rotation to be detected by optical microscopy. The rotational motion of F1-ATPase, which was immobilized on an inner surface of the test-bed chip, was measured to obtain the correlation between the near-surface flow and the rotation speed of F1-ATPase. As a result, we obtained the relationship that the rotation speed of F1-ATPase was linearly decelerated with increasing flow velocity. The mechanism of the correlation between the rotation speed and the near-surface flow remains unclear, however the concept to use biomolecule as a nano-flow-sensor was proofed successfully. (See supplementary material 1 Electronic supplementary material The online version of this article (doi:10.1007/s11671-009-9479-3 contains supplementary material, which is available to authorized users. Click here for file

  17. Flow structure from a horizontal cylinder coincident with a free surface in shallow water flow

    Directory of Open Access Journals (Sweden)

    Kahraman Ali

    2012-01-01

    Full Text Available Vortex formation from a horizontal cylinder coincident with a free surface of a shallow water flow having a depth of 25.4 [mm] was experimentally investigated using the PIV technique. Instantaneous and time-averaged flow patterns in the wake region of the cylinder were examined for three different cylinder diameter values under the fully developed turbulent boundary layer condition. Reynolds numbers were in the range of 1124£ Re£ 3374 and Froude numbers were in the range of 0.41 £ Fr £ 0.71 based on the cylinder diameter. It was found that a jet-like flow giving rise to increasing the flow entrainment between the core and wake regions depending on the cylinder diameter was formed between the lower surface of the cylinder and bottom surface of the channel. Vorticity intensity, Reynolds stress correlations and the primary recirculating bubble lengths were grown to higher values with increasing the cylinder diameter. On the other hand, in the case of the lowest level of the jet-like flow emanating from the beneath of the smallest cylinder, the variation of flow characteristics were attenuated significantly in a shorter distance. The variation of the reattachment location of the separated flow to the free-surface is a strong function of the cylinder diameter and the Froude number.

  18. Vortices generation in the reactive flow on the evaporative surface

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cha Ryeom; Lee, Chang Jin [Konkuk University, Seoul (Korea, Republic of)

    2015-02-15

    Vortices generation and flow dynamics are investigated by a numerical calculation with LES methodology on the evaporative surface including chemical reactions. For simplicity, fuel is radially injected from the surface in order to decouple pyrolysis of solid fuel from the governing equation and consideration of heat transfer balance. Nevertheless its simple treatment of chemical reactions and fuel pyrolysis, numerical results captured very fundamental understandings in terms of averaged temperature, velocity profile, and mixture fraction distribution. Results showed that a well-defined turbulent velocity profile at the inlet becomes twisted and highly wrinkled in the downstream reaching the maximum velocity at far above the surface, where the flame is located. And the thickness of boundary layer increases in the downstream due to the enhanced interaction of axial flow and mass injection from the surface. Also, chemical reaction appears highly active and partially concentrated along the plane where flow condition is in stoichiometric. In particular, flame front locates at the surface where mixture fraction Z equals to 0.07. Flame front severely wrinkles in the downstream by the interaction with turbulences in the flow. Partial reactions on the flame front contribute to produce hot spots periodically in the downstream attaining the max temperature at the center of each spot. This may take the role of additional unsteady heat generations and pressure perturbations in the downstream. Future study will focus on the evolution of hot spots and pressure perturbations in the post chamber of lab scale hybrid rocket motors.

  19. Darmstadt colloquium on hydrological engineering 1999: flow and dispersion processes in aquatic interstitials; Darmstaedter Wasserbauliches Kolloquium 1999: Fliess- und Ausbreitungsvorgaenge in aquatischen Grenzraeumen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    Anthropogenic effects have changed the patterns and intensities of pollutant transport into soil, groundwater and surface water, and water management has become a metter of great importance in the field of tension between water use and sustainability. Especially aquatic interstitials have great influence on environmental transport. The Darmstaedter Wasserbauliches Kolloquium (DAWAKO) 1999, which was held by the Institute of Hydrological Engineering and Water Management of TU Darmstadt University, discussed recent developments in the interstitials between unsaturated soil and groundwater, groundwater and flowing water, flowing water and floor. [German] Als Folge anthropogener Eingriffe in den Wasserkreislauf, z.B. infolge Landnutzungsaenderungen, Gewaesserausbau, Sieldungstaetigkeit usw. haben sich die Art und die Intensitaet des Stoffeintrages in Boden, Grundwasser sowie in die Oberflaechengewaesser erheblich gewandelt. Entsprechend sind zahlreiche wasserwirtschaftliche Fragestellungen im Spannungsfeld zwischen steigenden Anspruechen bei der Wassernutzung und dem Gebot einer nachhaltigen Bewirtschaftung dieser begrenzten Ressource zu behandeln. Es ist bekannt, dass aufgrund der periodisch wechselnden Milieubedingungen gerade den aquatischen Grenzraeumen eine besondere Bedeutung fuer den Stoffhaushalt zukommt. Neuere Entwicklungen bei den Prozessuntersuchungen in den Grenzraeumen zwischen: - ungesaettigter Bodenzone und Grundwasser - Grundwasser und Fliessgewaesser - Fliessgewaesser und Sohle (Interstitial) standen im Mittelpunkt des diesjaehrigen Darmstaedter Wasserbaulichen Kolloquiums (DAWAKO), das am 14. und 15. Oktober 1999 vom Institut fuer Wasserbau und Wasserwirtschaft der TU Darmstadt veranstaltet wurde. (orig.)

  20. Full Coupling Between the Atmosphere, Surface, and Subsurface for Integrated Hydrologic Simulation

    Science.gov (United States)

    Davison, Jason Hamilton; Hwang, Hyoun-Tae; Sudicky, Edward A.; Mallia, Derek V.; Lin, John C.

    2018-01-01

    An ever increasing community of earth system modelers is incorporating new physical processes into numerical models. This trend is facilitated by advancements in computational resources, improvements in simulation skill, and the desire to build numerical simulators that represent the water cycle with greater fidelity. In this quest to develop a state-of-the-art water cycle model, we coupled HydroGeoSphere (HGS), a 3-D control-volume finite element surface and variably saturated subsurface flow model that includes evapotranspiration processes, to the Weather Research and Forecasting (WRF) Model, a 3-D finite difference nonhydrostatic mesoscale atmospheric model. The two-way coupled model, referred to as HGS-WRF, exchanges the actual evapotranspiration fluxes and soil saturations calculated by HGS to WRF; conversely, the potential evapotranspiration and precipitation fluxes from WRF are passed to HGS. The flexible HGS-WRF coupling method allows for unique meshes used by each model, while maintaining mass and energy conservation between the domains. Furthermore, the HGS-WRF coupling implements a subtime stepping algorithm to minimize computational expense. As a demonstration of HGS-WRF's capabilities, we applied it to the California Basin and found a strong connection between the depth to the groundwater table and the latent heat fluxes across the land surface.

  1. Research on Land Surface Thermal-Hydrologic Exchange in Southern China under Future Climate and Land Cover Scenarios

    Directory of Open Access Journals (Sweden)

    Jianwu Yan

    2013-01-01

    Full Text Available Climate change inevitably leads to changes in hydrothermal circulation. However, thermal-hydrologic exchanging caused by land cover change has also undergone ineligible changes. Therefore, studying the comprehensive effects of climate and land cover changes on land surface water and heat exchanges enables us to well understand the formation mechanism of regional climate and predict climate change with fewer uncertainties. This study investigated the land surface thermal-hydrologic exchange across southern China for the next 40 years using a land surface model (ecosystem-atmosphere simulation scheme (EASS. Our findings are summarized as follows. (i Spatiotemporal variation patterns of sensible heat flux (H and evapotranspiration (ET under the land cover scenarios (A2a or B2a and climate change scenario (A1B are unanimous. (ii Both H and ET take on a single peak pattern, and the peak occurs in June or July. (iii Based on the regional interannual variability analysis, H displays a downward trend (10% and ET presents an increasing trend (15%. (iv The annual average H and ET would, respectively, increase and decrease by about 10% when woodland converts to the cultivated land. Through this study, we recognize that land surface water and heat exchanges are affected greatly by the future climate change as well as land cover change.

  2. A hydrological prediction system based on the SVS land-surface scheme: efficient calibration of GEM-Hydro for streamflow simulation over the Lake Ontario basin

    Directory of Open Access Journals (Sweden)

    É. Gaborit

    2017-09-01

    Full Text Available This work explores the potential of the distributed GEM-Hydro runoff modeling platform, developed at Environment and Climate Change Canada (ECCC over the last decade. More precisely, the aim is to develop a robust implementation methodology to perform reliable streamflow simulations with a distributed model over large and partly ungauged basins, in an efficient manner. The latest version of GEM-Hydro combines the SVS (Soil, Vegetation and Snow land-surface scheme and the WATROUTE routing scheme. SVS has never been evaluated from a hydrological point of view, which is done here for all major rivers flowing into Lake Ontario. Two established hydrological models are confronted to GEM-Hydro, namely MESH and WATFLOOD, which share the same routing scheme (WATROUTE but rely on different land-surface schemes. All models are calibrated using the same meteorological forcings, objective function, calibration algorithm, and basin delineation. GEM-Hydro is shown to be competitive with MESH and WATFLOOD: the NSE  √  (Nash–Sutcliffe criterion computed on the square root of the flows is for example equal to 0.83 for MESH and GEM-Hydro in validation on the Moira River basin, and to 0.68 for WATFLOOD. A computationally efficient strategy is proposed to calibrate SVS: a simple unit hydrograph is used for routing instead of WATROUTE. Global and local calibration strategies are compared in order to estimate runoff for ungauged portions of the Lake Ontario basin. Overall, streamflow predictions obtained using a global calibration strategy, in which a single parameter set is identified for the whole basin of Lake Ontario, show accuracy comparable to the predictions based on local calibration: the average NSE  √  in validation and over seven subbasins is 0.73 and 0.61, respectively for local and global calibrations. Hence, global calibration provides spatially consistent parameter values, robust performance at gauged locations, and reduces the

  3. A hydrological prediction system based on the SVS land-surface scheme: efficient calibration of GEM-Hydro for streamflow simulation over the Lake Ontario basin

    Science.gov (United States)

    Gaborit, Étienne; Fortin, Vincent; Xu, Xiaoyong; Seglenieks, Frank; Tolson, Bryan; Fry, Lauren M.; Hunter, Tim; Anctil, François; Gronewold, Andrew D.

    2017-09-01

    This work explores the potential of the distributed GEM-Hydro runoff modeling platform, developed at Environment and Climate Change Canada (ECCC) over the last decade. More precisely, the aim is to develop a robust implementation methodology to perform reliable streamflow simulations with a distributed model over large and partly ungauged basins, in an efficient manner. The latest version of GEM-Hydro combines the SVS (Soil, Vegetation and Snow) land-surface scheme and the WATROUTE routing scheme. SVS has never been evaluated from a hydrological point of view, which is done here for all major rivers flowing into Lake Ontario. Two established hydrological models are confronted to GEM-Hydro, namely MESH and WATFLOOD, which share the same routing scheme (WATROUTE) but rely on different land-surface schemes. All models are calibrated using the same meteorological forcings, objective function, calibration algorithm, and basin delineation. GEM-Hydro is shown to be competitive with MESH and WATFLOOD: the NSE √ (Nash-Sutcliffe criterion computed on the square root of the flows) is for example equal to 0.83 for MESH and GEM-Hydro in validation on the Moira River basin, and to 0.68 for WATFLOOD. A computationally efficient strategy is proposed to calibrate SVS: a simple unit hydrograph is used for routing instead of WATROUTE. Global and local calibration strategies are compared in order to estimate runoff for ungauged portions of the Lake Ontario basin. Overall, streamflow predictions obtained using a global calibration strategy, in which a single parameter set is identified for the whole basin of Lake Ontario, show accuracy comparable to the predictions based on local calibration: the average NSE √ in validation and over seven subbasins is 0.73 and 0.61, respectively for local and global calibrations. Hence, global calibration provides spatially consistent parameter values, robust performance at gauged locations, and reduces the complexity and computation burden of the

  4. Evaluation of global continental hydrology as simulated by the Land-surface Processes and eXchanges Dynamic Global Vegetation Model

    Directory of Open Access Journals (Sweden)

    S. J. Murray

    2011-01-01

    Full Text Available Global freshwater resources are sensitive to changes in climate, land cover and population density and distribution. The Land-surface Processes and eXchanges Dynamic Global Vegetation Model is a recent development of the Lund-Potsdam-Jena model with improved representation of fire-vegetation interactions. It allows simultaneous consideration of the effects of changes in climate, CO2 concentration, natural vegetation and fire regime shifts on the continental hydrological cycle. Here the model is assessed for its ability to simulate large-scale spatial and temporal runoff patterns, in order to test its suitability for modelling future global water resources. Comparisons are made against observations of streamflow and a composite dataset of modelled and observed runoff (1986–1995 and are also evaluated against soil moisture data and the Palmer Drought Severity Index. The model captures the main features of the geographical distribution of global runoff, but tends to overestimate runoff in much of the Northern Hemisphere (where this can be somewhat accounted for by freshwater consumption and the unrealistic accumulation of the simulated winter snowpack in permafrost regions and the southern tropics. Interannual variability is represented reasonably well at the large catchment scale, as are seasonal flow timings and monthly high and low flow events. Further improvements to the simulation of intra-annual runoff might be achieved via the addition of river flow routing. Overestimates of runoff in some basins could likely be corrected by the inclusion of transmission losses and direct-channel evaporation.

  5. Flow profiling of a surface acoustic wave nanopump

    OpenAIRE

    Guttenberg, Z.; Rathgeber, A.; Keller, S.; Rädler, J. O.; Wixforth, A.; Kostur, M.; Schindler, M.; Talkner, P.

    2004-01-01

    The flow profile in a capillary gap and the pumping efficiency of an acoustic micropump employing Surface Acoustic Waves is investigated both experimentally and theoretically. Such ultrasonic surface waves on a piezoelectric substrate strongly couple to a thin liquid layer and generate an internal streaming within the fluid. Such acoustic streaming can be used for controlled agitation during, e.g., microarray hybridization. We use fluorescence correlation spectroscopy and fluorescence microsc...

  6. Evaluation of ground-water flow and hydrologic budget for Lake Five-O, a seepage lake in northwestern Florida

    Science.gov (United States)

    Grubbs, J.W.

    1995-01-01

    Temporal and spatial distributions of ground-water inflow to, and leakage from Lake Five-O, a softwater, seepage lake in northwestern Florida, were evaluated using hydrologic data and simulation models of the shallow ground-water system adjacent to the lake. The simulation models indicate that ground-water inflow to the lake and leakage from the lake to the ground-water system are the dominant components in the total inflow (precipitation plus ground-water inflow) and total outflow (evaporation plus leakage) budgets of Lake Five-O. Simlulated ground-water inflow and leakage were approximately 4 and 5 times larger than precipitation inputs and evaporative losses, respectively, during calendar years 1989-90. Exchanges of water between Lake Five-O and the ground-water system were consistently larger than atmospheric-lake exchanges. A consistent pattern of shallow ground-water inflow and deep leakage was also evident throughout the study period. The mean time of travel from ground-water that discharges at Lake Five-O (time from recharge at the water table to discharge at the lake) was estimated to be within a range of 3 to 6 years. Flow-path evaluations indicated that the intermediate confining unit probably has a negligible influence on the geochemistry of ground-water inflow to Lake Five-O. The hydrologic budgets and flow-path evaluations provide critical information for developing geochemical budgets for Lake Five-O and for improving the understanding of the relative importance of various processes that regulate the acid-neutralizing capacity of softwater seepage lakes in Florida.

  7. Hydrologic controls on nitrogen cycling processes and functional gene abundance in sediments of a groundwater flow-through lake

    Science.gov (United States)

    Stoliker, Deborah L.; Repert, Deborah A.; Smith, Richard L.; Song, Bongkeun; LeBlanc, Denis R.; McCobb, Timothy D.; Conaway, Christopher; Hyun, Sung Pil; Koh, Dong-Chan; Moon, Hee Sun; Kent, Douglas B.

    2016-01-01

    The fate and transport of inorganic nitrogen (N) is a critically important issue for human and aquatic ecosystem health because discharging N-contaminated groundwater can foul drinking water and cause algal blooms. Factors controlling N-processing were examined in sediments at three sites with contrasting hydrologic regimes at a lake on Cape Cod, MA. These factors included water chemistry, seepage rates and direction of groundwater flow, and the abundance and potential rates of activity of N-cycling microbial communities. Genes coding for denitrification, anaerobic ammonium oxidation (anammox), and nitrification were identified at all sites regardless of flow direction or groundwater dissolved oxygen concentrations. Flow direction was, however, a controlling factor in the potential for N-attenuation via denitrification in the sediments. Potential rates of denitrification varied from 6 to 4500 pmol N/g/h from the inflow to the outflow side of the lake, owing to fundamental differences in the supply of labile organic matter. The results of laboratory incubations suggested that when anoxia and limiting labile organic matter prevailed, the potential existed for concomitant anammox and denitrification. Where oxic lake water was downwelling, potential rates of nitrification at shallow depths were substantial (1640 pmol N/g/h). Rates of anammox, denitrification, and nitrification may be linked to rates of organic N-mineralization, serving to increase N-mobility and transport downgradient.

  8. Sensitive analysis of low-flow parameters using the hourly hydrological model for two mountainous basins in Japan

    Science.gov (United States)

    Fujimura, Kazumasa; Iseri, Yoshihiko; Kanae, Shinjiro; Murakami, Masahiro

    2014-05-01

    Accurate estimation of low flow can contribute to better water resources management and also lead to more reliable evaluation of climate change impacts on water resources. In the early study, the nonlinearity of low flow related to the storage in the basin was suggested by Horton (1937) as the exponential function of Q=KSN, where Q is the discharge, S is the storage, K is a constant and N is the exponent value. In the recent study by Ding (2011) showed the general storage-discharge equation of Q = KNSN. Since the constant K is defined as the fractional recession constant and symbolized as Au by Ando et al. (1983), in this study, we rewrite this equation as Qg=AuNSgN, where Qg is the groundwater runoff and Sg is the groundwater storage. Although this equation was applied to a short-term runoff event of less than 14 hours using the unit hydrograph method by Ding, it was not yet applied for a long-term runoff event including low flow more than 10 years. This study performed a sensitive analysis of two parameters of the constant Au and exponent value N by using the hourly hydrological model for two mountainous basins in Japan. The hourly hydrological model used in this study was presented by Fujimura et al. (2012), which comprise the Diskin-Nazimov infiltration model, groundwater recharge and groundwater runoff calculations, and a direct runoff component. The study basins are the Sameura Dam basin (SAME basin) (472 km2) located in the western Japan which has variability of rainfall, and the Shirakawa Dam basin (SIRA basin) (205km2) located in a region of heavy snowfall in the eastern Japan, that are different conditions of climate and geology. The period of available hourly data for the SAME basin is 20 years from 1 January 1991 to 31 December 2010, and for the SIRA basin is 10 years from 1 October 2003 to 30 September 2013. In the sensitive analysis, we prepared 19900 sets of the two parameters of Au and N, the Au value ranges from 0.0001 to 0.0100 in steps of 0

  9. Chemical loading into surface water along a hydrological, biogeochemical, and land use gradient: A holistic watershed approach

    Science.gov (United States)

    Barber, L.B.; Murphy, S.F.; Verplanck, P.L.; Sandstrom, M.W.; Taylor, Howard E.; Furlong, E.T.

    2006-01-01

    Identifying the sources and impacts of organic and inorganic contaminants at the watershed scale is a complex challenge because of the multitude of processes occurring in time and space. Investigation of geochemical transformations requires a systematic evaluation of hydrologic, landscape, and anthropogenic factors. The 1160 km2 Boulder Creek Watershed in the Colorado Front Range encompasses a gradient of geology, ecotypes, climate, and urbanization. Streamflow originates primarily as snowmelt and shows substantial annual variation. Water samples were collected along a 70-km transect during spring-runoff and base-flow conditions, and analyzed for major elements, trace elements, bulk organics, organic wastewater contaminants (OWCs), and pesticides. Major-element and trace-element concentrations were low in the headwaters, increased through the urban corridor, and had a step increase downstream from the first major wastewater treatment plant (WWTP). Boron, gadolinium, and lithium were useful inorganic tracers of anthropogenic inputs. Effluent from the WWTP accounted for as much as 75% of the flow in Boulder Creek and was the largest chemical input. Under both hydrological conditions, OWCs and pesticides were detected in Boulder Creek downstream from the WWTP outfall as well as in the headwater region, and loads of anthropogenic-derived contaminants increased as basin population density increased. This report documents a suite of potential endocrine-disrupting chemicals in a reach of stream with native fish populations showing indication of endocrine disruption.

  10. Geomorphic and hydrologic study of peak-flow management on the Cedar River, Washington

    Science.gov (United States)

    Magirl, Christopher S.; Gendaszek, Andrew S.; Czuba, Christiana R.; Konrad, Christopher P.; Marineau, Mathieu D.

    2012-01-01

    Assessing the linkages between high-flow events, geomorphic response, and effects on stream ecology is critical to river management. High flows on the gravel-bedded Cedar River in Washington are important to the geomorphic function of the river; however, high flows can deleteriously affect salmon embryos incubating in streambed gravels. A geomorphic analysis of the Cedar River showed evidence of historical changes in river form over time and quantified the effects of anthropogenic alterations to the river corridor. Field measurements with accelerometer scour monitors buried in the streambed provided insight into the depth and timing of streambed scour during high-flow events. Combined with a two-dimensional hydrodynamic model, the recorded accelerometer disturbances allowed the prediction of streambed disturbance at the burial depth of Chinook and sockeye salmon egg pockets for different peak discharges. Insight gained from these analyses led to the development of suggested monitoring metrics for an ongoing geomorphic monitoring program on the Cedar River.

  11. Mechanics of fluid flow over compliant wrinkled polymeric surfaces

    Science.gov (United States)

    Raayai, Shabnam; McKinley, Gareth; Boyce, Mary

    2014-03-01

    Skin friction coefficients (based on frontal area) of sharks and dolphins are lower than birds, fish and swimming beetles. By either exploiting flow-induced changes in their flexible skin or microscale textures, dolphins and sharks can change the structure of the fluid flow around them and thus reduce viscous drag forces on their bodies. Inspired by this ability, investigators have tried using compliant walls and riblet-like textures as drag reduction methods in aircraft and marine industries and have been able to achieve reductions up to 19%. Here we investigate flow-structure interaction and wrinkling of soft polymer surfaces that can emulate shark riblets and dolphin's flexible skin. Wrinkling arises spontaneously as the result of mismatched deformation of a thin stiff coating bound to a thick soft elastic substrate. Wrinkles can be fabricated by controlling the ratio of the stiffness of the coating and substrate, the applied displacement and the thickness of the coating. In this work we will examine the evolution in the kinematic structures associated with steady viscous flow over the polymer wrinkled surfaces and in particular compare the skin friction with corresponding results for flow over non-textured and rigid surfaces.

  12. Transient flow between aquifers and surface water: analytically derived field-scale hydraulic heads and fluxes

    Directory of Open Access Journals (Sweden)

    G. H. de Rooij

    2012-03-01

    Full Text Available The increasing importance of catchment-scale and basin-scale models of the hydrological cycle makes it desirable to have a simple, yet physically realistic model for lateral subsurface water flow. As a first building block towards such a model, analytical solutions are presented for horizontal groundwater flow to surface waters held at prescribed water levels for aquifers with parallel and radial flow. The solutions are valid for a wide array of initial and boundary conditions and additions or withdrawals of water, and can handle discharge into as well as lateral infiltration from the surface water. Expressions for the average hydraulic head, the flux to or from the surface water, and the aquifer-scale hydraulic conductivity are developed to provide output at the scale of the modelled system rather than just point-scale values. The upscaled conductivity is time-variant. It does not depend on the magnitude of the flux but is determined by medium properties as well as the external forcings that drive the flow. For the systems studied, with lateral travel distances not exceeding 10 m, the circular aquifers respond very differently from the infinite-strip aquifers. The modelled fluxes are sensitive to the magnitude of the storage coefficient. For phreatic aquifers a value of 0.2 is argued to be representative, but considerable variations are likely. The effect of varying distributions over the day of recharge damps out rapidly; a soil water model that can provide accurate daily totals is preferable over a less accurate model hat correctly estimates the timing of recharge peaks.

  13. Relationships of dispersive mass transport and stochastic convective flow through hydrologic systems

    International Nuclear Information System (INIS)

    Simmons, C.S.

    1981-01-01

    Uncertainty in water flow velocity appears to be a major factor in determining the magnitude of contaminant dispersion expected in a ground water system. This report discusses some concepts and mathematical methods relating dispersive contaminant transport to stochastic aspects of ground water flow. The theory developed should not be construed as absolutely rigorous mathematics, but is presented with the intention of clarifying the physical concepts

  14. Drainage Structure Datasets and Effects on LiDAR-Derived Surface Flow Modeling

    Directory of Open Access Journals (Sweden)

    Ruopu Li

    2013-12-01

    Full Text Available With extraordinary resolution and accuracy, Light Detection and Ranging (LiDAR-derived digital elevation models (DEMs have been increasingly used for watershed analyses and modeling by hydrologists, planners and engineers. Such high-accuracy DEMs have demonstrated their effectiveness in delineating watershed and drainage patterns at fine scales in low-relief terrains. However, these high-resolution datasets are usually only available as topographic DEMs rather than hydrologic DEMs, presenting greater land roughness that can affect natural flow accumulation. Specifically, locations of drainage structures such as road culverts and bridges were simulated as barriers to the passage of drainage. This paper proposed a geospatial method for producing LiDAR-derived hydrologic DEMs, which incorporates data collection of drainage structures (i.e., culverts and bridges, data preprocessing and burning of the drainage structures into DEMs. A case study of GIS-based watershed modeling in South Central Nebraska showed improved simulated surface water derivatives after the drainage structures were burned into the LiDAR-derived topographic DEMs. The paper culminates in a proposal and discussion of establishing a national or statewide drainage structure dataset.

  15. Moving least squares simulation of free surface flows

    DEFF Research Database (Denmark)

    Felter, C. L.; Walther, Jens Honore; Henriksen, Christian

    2014-01-01

    In this paper a Moving Least Squares method (MLS) for the simulation of 2D free surface flows is presented. The emphasis is on the governing equations, the boundary conditions, and the numerical implementation. The compressible viscous isothermal Navier–Stokes equations are taken as the starting ...

  16. Numerical simulations of viscoelastic flows with free surfaces

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    2013-01-01

    We present a new methodology to simulate viscoelastic flows with free-surfaces. These simulations are motivated by the modelling of polymers manufacturing techniques, such as extrusion and injection moulding. One of the consequences of viscoelasticity is that polymeric materials have a “memory...

  17. Nitrogen Transformation and Removal in Horizontal Surface Flow ...

    African Journals Online (AJOL)

    The potential use of Constructed Mangrove Wetlands (CMWs) as a cheaper, effective and appropriate method for Nitrogen removal from domestic sewage of coastal zone in peri-urban cities was investigated from August 2007 to. September, 2008. Field investigations were made on horizontal surface flow constructed ...

  18. A comprehensive approach to identify dominant controls of the behavior of a land surface-hydrology model across various hydroclimatic conditions

    Science.gov (United States)

    Haghnegahdar, Amin; Elshamy, Mohamed; Yassin, Fuad; Razavi, Saman; Wheater, Howard; Pietroniro, Al

    2017-04-01

    Complex physically-based environmental models are being increasingly used as the primary tool for watershed planning and management due to advances in computation power and data acquisition. Model sensitivity analysis plays a crucial role in understanding the behavior of these complex models and improving their performance. Due to the non-linearity and interactions within these complex models, Global sensitivity analysis (GSA) techniques should be adopted to provide a comprehensive understanding of model behavior and identify its dominant controls. In this study we adopt a multi-basin multi-criteria GSA approach to systematically assess the behavior of the Modélisation Environmentale-Surface et Hydrologie (MESH) across various hydroclimatic conditions in Canada including areas in the Great Lakes Basin, Mackenzie River Basin, and South Saskatchewan River Basin. MESH is a semi-distributed physically-based coupled land surface-hydrology modelling system developed by Environment and Climate Change Canada (ECCC) for various water resources management purposes in Canada. We use a novel method, called Variogram Analysis of Response Surfaces (VARS), to perform sensitivity analysis. VARS is a variogram-based GSA technique that can efficiently provide a spectrum of sensitivity information across a range of scales within the parameter space. We use multiple metrics to identify dominant controls of model response (e.g. streamflow) to model parameters under various conditions such as high flows, low flows, and flow volume. We also investigate the influence of initial conditions on model behavior as part of this study. Our preliminary results suggest that this type of GSA can significantly help with estimating model parameters, decreasing calibration computational burden, and reducing prediction uncertainty.

  19. Simulation of integrated surface-water/ground-water flow and salinity for a coastal wetland and adjacent estuary

    Science.gov (United States)

    Langevin, C.; Swain, E.; Wolfert, M.

    2005-01-01

    The SWIFT2D surface-water flow and transport code, which solves the St Venant equations in two dimensions, was coupled with the SEAWAT variable-density ground-water code to represent hydrologic processes in coastal wetlands and adjacent estuaries. A sequentially coupled time-lagged approach was implemented, based on a variable-density form of Darcy's Law, to couple the surface and subsurface systems. The integrated code also represents the advective transport of salt mass between the surface and subsurface. The integrated code was applied to the southern Everglades of Florida to quantify flow and salinity patterns and to evaluate effects of hydrologic processes. Model results confirm several important observations about the coastal wetland: (1) the coastal embankment separating the wetland from the estuary is overtopped only during tropical storms, (2) leakage between the surface and subsurface is locally important in the wetland, but submarine ground-water discharge does not contribute large quantities of freshwater to the estuary, and (3) coastal wetland salinities increase to near seawater values during the dry season, and the wetland flushes each year with the onset of the wet season. ?? 2005 Elsevier B.V. All rights reserved.

  20. A surface-renewal model of cross-flow microfiltration

    Directory of Open Access Journals (Sweden)

    A. Hasan

    2013-03-01

    Full Text Available A mathematical model using classical cake-filtration theory and the surface-renewal concept is formulated for describing cross-flow microfiltration under dynamic and steady-state conditions. The model can predict the permeate flux and cake buildup in the filter. The three basic parameters of the model are the membrane resistance, specific cake resistance and rate of surface renewal. The model is able to correlate experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory- and pilot-scale units with an average root-mean-square (RMS error of 4.6%. The experimental data are also compared against the critical-flux model of cross-flow microfiltration, which has average RMS errors of 6.3, 5.5 and 6.1% for the cases of cake filtration, intermediate blocking and complete blocking mechanisms, respectively.

  1. High flows in the 21st Century: analysis with a simple conceptual hydrological models using the input of 3 GCMs (A2 scenario)

    NARCIS (Netherlands)

    Lanen, H.A.J.; Wanders, N.

    2011-01-01

    The study on high flows with a conceptual hydrological model leads to the following conclusions for about 1500 randomly selected land points across the world that have an intermediate soil water supply capacity and an intermediary responding groundwater system: · the probability distributions of

  2. Phase II Hydrologic Data for the Groundwater Flow and Contaminant Transport Model of Corrective Action Unit 98: Frenchman Flat, Nye County, Nevada, Rev. No.: 0

    Energy Technology Data Exchange (ETDEWEB)

    John McCord

    2004-12-01

    This report documents pertinent hydrologic data and data analyses as part of the Phase II Corrective Action Investigation (CAI) for Frenchman Flat (FF) Corrective Action Unit (CAU): CAU 98. The purpose of this data compilation and related analyses is to provide the primary reference to support the development of the Phase II FF CAU groundwater flow model.

  3. The influence of flow-through saline gravel pit lakes on the hydrologic budget and hydrochemistry of a Mediterranean drainage basin

    NARCIS (Netherlands)

    Mollema, P.N.; Antonellini, Marco; Dinelli, Enrico; Greggio, Nicolas; Stuijfzand, Pieter

    2015-01-01

    Flow-through brackish gravel pit lakes near the Adriatic Coast of Emilia Romagna (Italy) in the Mediterranean have a large influence on the hydrologic budget of the watershed. Strong evaporation in combination with intense drainage of the low lying basins enhances groundwater inflow into the

  4. Integral methods for shallow free-surface flows with separation

    DEFF Research Database (Denmark)

    Watanabe, S.; Putkaradze, V.; Bohr, Tomas

    2003-01-01

    eddy and separated flow. Assuming a variable radial velocity profile as in Karman-Pohlhausen's method, we obtain a system of two ordinary differential equations for stationary states that can smoothly go through the jump. Solutions of the system are in good agreement with experiments. For the flow down...... an inclined plane we take a similar approach and derive a simple model in which the velocity profile is not restricted to a parabolic or self-similar form. Two types of solutions with large surface distortions are found: solitary, kink-like propagating fronts, obtained when the flow rate is suddenly changed......, and stationary jumps, obtained, for instance, behind a sluice gate. We then include time dependence in the model to study the stability of these waves. This allows us to distinguish between sub- and supercritical flows by calculating dispersion relations for wavelengths of the order of the width of the layer....

  5. U.S. Geological Survey groundwater toolbox, a graphical and mapping interface for analysis of hydrologic data (version 1.0): user guide for estimation of base flow, runoff, and groundwater recharge from streamflow data

    Science.gov (United States)

    Barlow, Paul M.; Cunningham, William L.; Zhai, Tong; Gray, Mark

    2015-01-01

    This report is a user guide for the streamflow-hydrograph analysis methods provided with version 1.0 of the U.S. Geological Survey (USGS) Groundwater Toolbox computer program. These include six hydrograph-separation methods to determine the groundwater-discharge (base-flow) and surface-runoff components of streamflow—the Base-Flow Index (BFI; Standard and Modified), HYSEP (Fixed Interval, Sliding Interval, and Local Minimum), and PART methods—and the RORA recession-curve displacement method and associated RECESS program to estimate groundwater recharge from streamflow data. The Groundwater Toolbox is a customized interface built on the nonproprietary, open source MapWindow geographic information system software. The program provides graphing, mapping, and analysis capabilities in a Microsoft Windows computing environment. In addition to the four hydrograph-analysis methods, the Groundwater Toolbox allows for the retrieval of hydrologic time-series data (streamflow, groundwater levels, and precipitation) from the USGS National Water Information System, downloading of a suite of preprocessed geographic information system coverages and meteorological data from the National Oceanic and Atmospheric Administration National Climatic Data Center, and analysis of data with several preprocessing and postprocessing utilities. With its data retrieval and analysis tools, the Groundwater Toolbox provides methods to estimate many of the components of the water budget for a hydrologic basin, including precipitation; streamflow; base flow; runoff; groundwater recharge; and total, groundwater, and near-surface evapotranspiration.

  6. Incompressible flows of superfluid films on multiply-connected surfaces

    International Nuclear Information System (INIS)

    Corrada-Emmanuel, A.

    1989-01-01

    The theory of Riemann surfaces is applied to the problem of constructing quantized vortex flows in closed surfaces of arbitrary but finite genus. An in principle procedure for obtaining the lowest energy flow is presented. It is shown that quantized vortices in non-zero genus surfaces are, in general, not isomorphic to a Coulomb gas. This failure has a geometrical origin: the appearance in non-zero genus surfaces of closed curves that are not the boundary of any area. A theorem of Riemann is applied to the genus one surface, the torus, to show quantitatively how to construct the quantized vortices. Because of the breakdown in the isomorphism between quantized vortices and charges, a novel effect is possible: the violation of Earnshaw's theorem. On a torus a single vortex can be placed in local stable equilibrium. The uniform flows around the holes of the torus also lead to a new result: a non-vortex mechanism for the destruction of superfluidity in the film. An explicit formula is derived showing this effect by considering the response of a helium film to a rotation of the torus. The author predicts that torii of dissimilar proportions will exhibit different superfluid densities at the same temperature

  7. Modelling hydrological connectivity in semi-arid flat areas: effect of the flow accumulation algorithm on the spatial pattern

    Science.gov (United States)

    López-Vicente, Manuel; Álvarez, Sara

    2017-04-01

    Much of the water and sediment fluxes in semi-arid landscapes are found to be concentrated in localized pathways. Identifying the location of these pathways is important for management and restoration. This task becomes more complicated in flat areas, such as alluvial terraces, where geomorphic features of concentrated overland flow (rills and ephemeral gullies) are scarce or inexistent. Field identification of sediment delivery pathways as well as depositional areas is also difficult and challenged. The concept of hydrological connectivity (HC) helps us to express the complexity of landscape non-linear responses to rainfall inputs. One of the unsolved issues in overland flow modelling studies is the choice of the right flow accumulation algorithm (FAA). There is an abundant literature on runoff generation under semi-arid conditions, and relating HC and land use management and changes. However, we found a scientific gap in the literature focussed on modelling of HC in flat areas under semi-arid conditions. This study aims to fill in this gap by modelling HC in alluvial terraces (28 ha) in NE Spain under semi-arid conditions (342 mm / year), mainly devoted to rain-fed cereal fields, by using eight FAA. For this purpose, we applied a modified version of the Borselli's index of runoff and sediment connectivity (IC). The study area includes seven fields on flat alluvial terraces, three fields on a gentle slope, small patches of scrubland, and twelve grass buffer strips that are located between each set of fields. Gentle and flat areas (S drone (model eBee by senseFly Ltd.). In order to minimize the effect of the vegetation on the photogrammetry restitution technique, pictures were taken in early spring, before the growth of the cereals. Then, several DEMs were generated independently. For this study, we chose the DEM at 0.5 x 0.5 m of spatial resolution. Before running the IC model, the continuity of the flow path lines throughout the landscape was ensured by removing

  8. Hydrologic assessment of the shallow groundwater flow system beneath the Shinnecock Nation tribal lands, Suffolk County, New York

    Science.gov (United States)

    Noll, Michael L.; Rivera, Simonette L.; Busciolano, Ronald J.

    2016-12-02

    Defining the distribution and flow of shallow groundwater beneath the Shinnecock Nation tribal lands in Suffolk County, New York, is a crucial first step in identifying sources of potential contamination to the surficial aquifer and coastal ecosystems. The surficial or water table aquifer beneath the tribal lands is the primary source of potable water supply for at least 6 percent of the households on the tribal lands. Oyster fisheries and other marine ecosystems are critical to the livelihood of many residents living on the tribal lands, but are susceptible to contamination from groundwater entering the embayment from the surficial aquifer. Contamination of the surficial aquifer from flooding during intense coastal storms, nutrient loading from fertilizers, and septic effluent have been identified as potential sources of human and ecological health concerns on tribal lands.The U.S. Geological Survey (USGS) facilitated the installation of 17 water table wells on and adjacent to the tribal lands during March 2014. These wells were combined with other existing wells to create a 32-well water table monitoring network that was used to assess local hydrologic conditions. Survey-grade, global-navigation-satellite systems provided centimeter-level accuracy for positioning wellhead surveys. Water levels were measured by the USGS during May (spring) and November (fall) 2014 to evaluate seasonal effects on the water table. Water level measurements were made at high and low tide during May 2014 to identify potential effects on the water table caused by changes in tidal stage (tidal flux) in Shinnecock Bay. Water level contour maps indicate that the surficial aquifer is recharged by precipitation and upgradient groundwater flow that moves from the recharge zone located generally beneath Sunrise Highway, to the discharge zone beneath the tribal lands, and eventually discharges into the embayment, tidal creeks, and estuaries that bound the tribal lands to the east, south, and

  9. Experimental and numerical modelling of surface water-groundwater flow and pollution interactions under tidal forcing

    Science.gov (United States)

    Spanoudaki, Katerina; Bockelmann-Evans, Bettina; Schaefer, Florian; Kampanis, Nikolaos; Nanou-Giannarou, Aikaterini; Stamou, Anastasios; Falconer, Roger

    2015-04-01

    Surface water and groundwater are integral components of the hydrologic continuum and the interaction between them affects both their quantity and quality. However, surface water and groundwater are often considered as two separate systems and are analysed independently. This separation is partly due to the different time scales, which apply in surface water and groundwater flows and partly due to the difficulties in measuring and modelling their interactions (Winter et al., 1998). Coastal areas in particular are a difficult hydrologic environment to represent with a mathematical model due to the large number of contributing hydrologic processes. Accurate prediction of interactions between coastal waters, groundwater and neighbouring wetlands, for example, requires the use of integrated surface water-groundwater models. In the past few decades a large number of mathematical models and field methods have been developed in order to quantify the interaction between groundwater and hydraulically connected surface water bodies. Field studies may provide the best data (Hughes, 1995) but are usually expensive and involve too many parameters. In addition, the interpretation of field measurements and linking with modelling tools often proves to be difficult. In contrast, experimental studies are less expensive and provide controlled data. However, experimental studies of surface water-groundwater interaction are less frequently encountered in the literature than filed studies (e.g. Ebrahimi et al., 2007; Kuan et al., 2012; Sparks et al., 2013). To this end, an experimental model has been constructed at the Hyder Hydraulics Laboratory at Cardiff University to enable measurements to be made of groundwater transport through a sand embankment between a tidal water body such as an estuary and a non-tidal water body such as a wetland. The transport behaviour of a conservative tracer was studied for a constant water level on the wetland side of the embankment, while running a

  10. CURVATURE-DRIVEN MOLECULAR FLOW ON MEMBRANE SURFACE.

    Science.gov (United States)

    Mikucki, Michael; Zhou, Y C

    2017-01-01

    This work presents a mathematical model for the localization of multiple species of diffusion molecules on membrane surfaces. Morphological change of bilayer membrane in vivo is generally modulated by proteins. Most of these modulations are associated with the localization of related proteins in the crowded lipid environments. We start with the energetic description of the distributions of molecules on curved membrane surface, and define the spontaneous curvature of bilayer membrane as a function of the molecule concentrations on membrane surfaces. A drift-diffusion equation governs the gradient flow of the surface molecule concentrations. We recast the energetic formulation and the related governing equations by using an Eulerian phase field description to define membrane morphology. Computational simulations with the proposed mathematical model and related numerical techniques predict (i) the molecular localization on static membrane surfaces at locations with preferred mean curvatures, and (ii) the generation of preferred mean curvature which in turn drives the molecular localization.

  11. Investigation of aluminum surface cleaning using cavitating fluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Ralys, Aurimas; Striška, Vytautas; Mokšin, Vadim [Vilnius Gediminas Technical University, Faculty of Mechanics, Department of Machine Engineering, J. Basanavičiaus str.28, 03224, Vilnius (Lithuania)

    2013-12-16

    This paper investigates efficiency of specially designed atomizer used to spray water and cavitate microbubbles in water flow. Surface cleaning system was used to clean machined (grinded) aluminum surface from abrasive particles. It is established that cleaning efficiency depends on diameter of the diffuser, water pressure and distance between nozzle and metal surface. It is obtained that the best cleaning efficiency (100%) is achieved at pressure 36 bar, when diameter of diffuser is 0.4 mm and distance between nozzle and surface is 1 mm. It is also established that satisfactory cleaning efficiency (80%) is achieved not only when atomizer is placed closer to metal surface, but also at larger (120 mm) distances.

  12. Geophysical logging and hydrologic testing of deep basalt flows in the Rattlesnake Hills Well Number One

    International Nuclear Information System (INIS)

    Gephart, R.E.; Eddy, P.A.; Deju, R.A.

    1979-01-01

    Geophysical logging and hydrologic testing were conducted in the Rattlesnake Hills Well Number One located along the western boundary of the Hanford Site in south-central Washington. Three-dimensional velocity, Seisviewer and caliper logging were completed across 2,000 feet of basalt rock within the Wanapum and Grande Ronde formations. Drillstem testing focused along a 250-foot interval of the Grande Ronde Formation. Individual high- (approx. 2.7-2.9 grams per cubic centimeter) and low-density (approx. 2.3-2.6 grams per cubic centimeter) basalt zones within the Wanapum Formation are generally less than 50 feet thick. Within the estimated thickness of the Grande Ronde Formation, 85 percent of the low-density zones are less than 50 feet thick, compared to 55 percent of those of higher density. The Grande Ronde Formation has 13 high-density zones varying in thickness from 51 to 230 feet. Logging data suggest the thicknesses of low-density are independent of the thicknesses of the associated and underlying higher density columnar basalts. Eleven drillstem tests were conducted across selected intervals within the Grande Ronde Formation. Hydraulic conductivity values calculated for the low-density basalt zones ranged between 1.7 x 10 -7 and 3.8 x 10 -9 centimeters per second; those for high-density zones were between 1.1 x 10 -8 and 4.7 x 10 -9 centimeters per second

  13. Simulation of groundwater and surface-water flow in the upper Deschutes Basin, Oregon

    Science.gov (United States)

    Gannett, Marshall W.; Lite, Kenneth E.; Risley, John C.; Pischel, Esther M.; La Marche, Jonathan L.

    2017-10-20

    This report describes a hydrologic model for the upper Deschutes Basin in central Oregon developed using the U.S. Geological Survey (USGS) integrated Groundwater and Surface-Water Flow model (GSFLOW). The upper Deschutes Basin, which drains much of the eastern side of the Cascade Range in Oregon, is underlain by large areas of permeable volcanic rock. That permeability, in combination with the large annual precipitation at high elevations, results in a substantial regional aquifer system and a stream system that is heavily groundwater dominated.The upper Deschutes Basin is also an area of expanding population and increasing water demand for public supply and agriculture. Surface water was largely developed for agricultural use by the mid-20th century, and is closed to additional appropriations. Consequently, water users look to groundwater to satisfy the growing demand. The well‑documented connection between groundwater and the stream system, and the institutional and legal restrictions on streamflow depletion by wells, resulted in the Oregon Water Resources Department (OWRD) instituting a process whereby additional groundwater pumping can be permitted only if the effects to streams are mitigated, for example, by reducing permitted surface-water diversions. Implementing such a program requires understanding of the spatial and temporal distribution of effects to streams from groundwater pumping. A groundwater model developed in the early 2000s by the USGS and OWRD has been used to provide insights into the distribution of streamflow depletion by wells, but lacks spatial resolution in sensitive headwaters and spring areas.The integrated model developed for this project, based largely on the earlier model, has a much finer grid spacing allowing resolution of sensitive headwater streams and important spring areas, and simulates a more complete set of surface processes as well as runoff and groundwater flow. In addition, the integrated model includes improved

  14. Assessing the impact of model spin-up on surface water-groundwater interactions using an integrated hydrologic model

    KAUST Repository

    Ajami, Hoori; McCabe, Matthew; Evans, Jason P.; Stisen, Simon

    2014-01-01

    is to minimize the impact of initialization while using the smallest spin-up time possible. In this study, multicriteria analysis was performed to assess the spin-up behavior of the ParFlow.CLM integrated groundwater-surface water-land surface model over a 208 km

  15. Using isotopes to improve impact and hydrological predictions of land-surface schemes in global climate models

    International Nuclear Information System (INIS)

    McGuffie, K.; Henderson-Sellers, A.

    2002-01-01

    Global climate model (GCM) predictions of the impact of large-scale land-use change date back to 1984 as do the earliest isotopic studies of large-basin hydrology. Despite this coincidence in interest and geography, with both papers focussed on the Amazon, there have been few studies that have tried to exploit isotopic information with the goal of improving climate model simulations of the land-surface. In this paper we analyze isotopic results from the IAEA global data base specifically with the goal of identifying signatures of potential value for improving global and regional climate model simulations of the land-surface. Evaluation of climate model predictions of the impacts of deforestation of the Amazon has been shown to be of significance by recent results which indicate impacts occurring distant from the Amazon i.e. tele-connections causing climate change elsewhere around the globe. It is suggested that these could be similar in magnitude and extent to the global impacts of ENSO events. Validation of GCM predictions associated with Amazonian deforestation are increasingly urgently required because of the additional effects of other aspects of climate change, particularly synergies occurring between forest removal and greenhouse gas increases, especially CO 2 . Here we examine three decades distributions of deuterium excess across the Amazon and use the results to evaluate the relative importance of the fractionating (partial evaporation) and non-fractionating (transpiration) processes. These results illuminate GCM scenarios of importance to the regional climate and hydrology: (i) the possible impact of increased stomatal resistance in the rainforest caused by higher levels of atmospheric CO2 [4]; and (ii) the consequences of the combined effects of deforestation and global warming on the regions climate and hydrology

  16. Characterizing developing adverse pressure gradient flows subject to surface roughness

    Science.gov (United States)

    Brzek, Brian; Chao, Donald; Turan, Özden; Castillo, Luciano

    2010-04-01

    An experimental study was conducted to examine the effects of surface roughness and adverse pressure gradient (APG) on the development of a turbulent boundary layer. Hot-wire anemometry measurements were carried out using single and X-wire probes in all regions of a developing APG flow in an open return wind tunnel test section. The same experimental conditions (i.e., T ∞, U ref, and C p) were maintained for smooth, k + = 0, and rough, k + = 41-60, surfaces with Reynolds number based on momentum thickness, 3,000 carefully designed such that the x-dependence in the flow field was known. Despite this fact, only a very small region of the boundary layer showed a balance of the various terms in the integrated boundary layer equation. The skin friction computed from this technique showed up to a 58% increase due to the surface roughness. Various equilibrium parameters were studied and the effect of roughness was investigated. The generated flow was not in equilibrium according to the Clauser (J Aero Sci 21:91-108, 1954) definition due to its developing nature. After a development region, the flow reached the equilibrium condition as defined by Castillo and George (2001), where Λ = const, is the pressure gradient parameter. Moreover, it was found that this equilibrium condition can be used to classify developing APG flows. Furthermore, the Zagarola and Smits (J Fluid Mech 373:33-79, 1998a) scaling of the mean velocity deficit, U ∞δ*/δ, can also be used as a criteria to classify developing APG flows which supports the equilibrium condition of Castillo and George (2001). With this information a ‘full APG region’ was defined.

  17. Free surface flow with moving rigid bodies. Part 1. Computational flow model

    International Nuclear Information System (INIS)

    Gubanov, O.I.; Mironova, L.A.; Kocabiyik, S.

    2005-01-01

    This paper was motivated by the study of Hirt and Sicilian, where the 'differential form' of the governing equations for the inviscid fluid flow (FAVOR equations) were obtained. We utilize mainly generalized differentiation to extend the Reynolds transport theorem over a control volume containing fluid interface for deriving the 'integral form' of governing equations for the incompressible viscous flow problems. This is done following the work by Farassat and the use of generalized function theory made this derivation straightforward, systematic and rigorous. The resulting equations are discretized by a finite-volume method using a staggered grid, after making use of the coarse-scale approximation. The resulting governing equations are valid for a class of flows including free surface flows with arbitrarily moving bodies and are consistent with Hirt and Sicilian's formulation in the inviscid fluid flow case. (author)

  18. Characterization of groundwater flow for near surface disposal facilities

    International Nuclear Information System (INIS)

    2001-02-01

    The main objective of this report is to provide a description of the site investigation techniques and modelling approaches that can be used to characterise the flow of subsurface water at near surface disposal facilities in relation to the various development stages of the repositories. As one of the main goals of defining groundwater flow is to establish the possible contaminant migration, certain aspects related to groundwater transport are also described. Secondary objectives are to discuss the implications of various groundwater conditions with regard to the performance of the isolation systems

  19. Surface and Flow Field Measurements on the FAITH Hill Model

    Science.gov (United States)

    Bell, James H.; Heineck, James T.; Zilliac, Gregory; Mehta, Rabindra D.; Long, Kurtis R.

    2012-01-01

    A series of experimental tests, using both qualitative and quantitative techniques, were conducted to characterize both surface and off-surface flow characteristics of an axisymmetric, modified-cosine-shaped, wall-mounted hill named "FAITH" (Fundamental Aero Investigates The Hill). Two separate models were employed: a 6" high, 18" base diameter machined aluminum model that was used for wind tunnel tests and a smaller scale (2" high, 6" base diameter) sintered nylon version that was used in the water channel facility. Wind tunnel and water channel tests were conducted at mean test section speeds of 165 fps (Reynolds Number based on height = 500,000) and 0.1 fps (Reynolds Number of 1000), respectively. The ratio of model height to boundary later height was approximately 3 for both tests. Qualitative techniques that were employed to characterize the complex flow included surface oil flow visualization for the wind tunnel tests, and dye injection for the water channel tests. Quantitative techniques that were employed to characterize the flow included Cobra Probe to determine point-wise steady and unsteady 3D velocities, Particle Image Velocimetry (PIV) to determine 3D velocities and turbulence statistics along specified planes, Pressure Sensitive Paint (PSP) to determine mean surface pressures, and Fringe Imaging Skin Friction (FISF) to determine surface skin friction (magnitude and direction). This initial report summarizes the experimental set-up, techniques used, data acquired and describes some details of the dataset that is being constructed for use by other researchers, especially the CFD community. Subsequent reports will discuss the data and their interpretation in more detail

  20. Impacts of land use and land cover change on surface runoff, discharge and low flows: Evidence from East Africa

    Directory of Open Access Journals (Sweden)

    A.C. Guzha

    2018-02-01

    New hydrological insights: Forest cover loss is accompanied by increased stream discharges and surface runoff. No significant difference in stream discharge is observed between bamboo and pine plantation catchments, and between cultivated and tea plantation catchments. Trend analyses show that despite forest cover loss, 63% of the watersheds show non-significant changes in annual discharges while 31% show increasing trends. Half of the watersheds show non-significant trends in wet season flows and low flows while 35% reveal decreasing trends in low flows. Modeling studies estimate that forest cover loss increases annual discharges and surface runoff by 16 ± 5.5% and 45 ± 14%, respectively. Peak flows increased by a mean of 10 ± 2.8% while low flows decreased by a mean of 7 ± 5.3%. Increased forest cover decreases annual discharges and surface runoff by 13 ± 1.9% and 25 ± 5%, respectively. Weak correlations between forest cover and runoff (r = 0.42, p < 0.05, mean discharge (r = 0.63, p < 0.05 and peak discharge (r = 0.67, p < 0.05 indicate that forest cover alone is not an accurate predictor of hydrological fluxes in East African catchments. The variability in these results supports the need for long-term field monitoring to better understand catchment responses and to improve the calibration of currently used simulation models.

  1. Study on uncertainty evaluation methodology related to hydrological parameter of regional groundwater flow analysis model

    International Nuclear Information System (INIS)

    Sakai, Ryutaro; Munakata, Masahiro; Ohoka, Masao; Kameya, Hiroshi

    2009-11-01

    In the safety assessment for a geological disposal of radioactive waste, it is important to develop a methodology for long-term estimation of regional groundwater flow from data acquisition to numerical analyses. In the uncertainties associated with estimation of regional groundwater flow, there are the one that concerns parameters and the one that concerns the hydrologeological evolution. The uncertainties of parameters include measurement errors and their heterogeneity. The authors discussed the uncertainties of hydraulic conductivity as a significant parameter for regional groundwater flow analysis. This study suggests that hydraulic conductivities of rock mass are controlled by rock characteristics such as fractures, porosity and test conditions such as hydraulic gradient, water quality, water temperature and that there exists variations more than ten times in hydraulic conductivity by difference due to test conditions such as hydraulic gradient or due to rock type variations such as rock fractures, porosity. In addition this study demonstrated that confining pressure change caused by uplift and subsidence and change of hydraulic gradient under the long-term evolution of hydrogeological environment could possibly produce variations more than ten times of magnitude in hydraulic conductivity. It was also shown that the effect of water quality change on hydraulic conductivity was not negligible and that the replacement of fresh water and saline water caused by sea level change could induce 0.6 times in current hydraulic conductivities in case of Horonobe site. (author)

  2. Surface erosion and hydrology of earth covers used in shallow land burial of low-level radioactive waste

    International Nuclear Information System (INIS)

    Bent, G.C.

    1988-01-01

    Shallow land burial is the current method of disposal of low-level radioactive waste in the United States. The most serious technical problems encountered in shallow land burial are water-related. Water is reported to come into contact with the waste by erosion of earth covers or through infiltration of precipitation through the earth covers. The objectives of this study were to: compare and evaluate the effects of crested wheatgrass and streambank wheatgrass on surface erosion of simulated earth covers at Idaho National Engineering Laboratory (INEL), characterize the surface hydrology, and estimate cumulative soil loss for average and extreme rainfall events and determine if the waste will become exposed during its burial life due to erosion. 30 refs., 26 figs., 21 tabs

  3. a Matlab Toolbox for Basin Scale Fluid Flow Modeling Applied to Hydrology and Geothermal Energy

    Science.gov (United States)

    Alcanie, M.; Lupi, M.; Carrier, A.

    2017-12-01

    Recent boosts in the development of geothermal energy were fostered by the latest oil crises and by the need of reducing CO2 emissions generated by the combustion of fossil fuels. Various numerical codes (e.g. FEHM, CSMP++, HYDROTHERM, TOUGH) have thus been implemented for the simulation and quantification of fluid flow in the upper crust. One possible limitation of such codes is the limited accessibility and the complex structure of the simulators. For this reason, we began to develop a Hydrothermal Fluid Flow Matlab library as part of MRST (Matlab Reservoir Simulation Toolbox). MRST is designed for the simulation of oil and gas problems including carbon capture storage. However, a geothermal module is still missing. We selected the Geneva Basin as a natural laboratory because of the large amount of data available in the region. The Geneva Basin has been intensely investigated in the past with exploration wells, active seismic and gravity surveys. In addition, the energy strategy of Switzerland promotes the development of geothermal energy that lead to recent geophysical prospections. Previous and ongoing projects have shown the geothermal potential of the Geneva Basin but a consistent fluid flow model assessing the deep circulation in the region is yet to be defined. The first step of the study was to create the basin-scale static model. We integrated available active seismic, gravity inversions and borehole data to describe the principal geologic and tectonic features of the Geneva Basin. Petrophysical parameters were obtained from available and widespread well logs. This required adapting MRST to standard text format file imports and outline a new methodology for quick static model creation in an open source environment. We implemented several basin-scale fluid flow models to test the effects of petrophysical properties on the circulation dynamics of deep fluids in the Geneva Basin. Preliminary results allow the identification of preferential fluid flow

  4. A waveless free surface flow past a submerged triangular obstacle in presence of surface tension

    Directory of Open Access Journals (Sweden)

    Hakima Sekhri

    2016-07-01

    Full Text Available We consider the Free surface flows passing a submerged triangular obstacle at the bottom of a channel. The problem is characterized by a nonlinear boundary condition on the surface of unknown configuration. The analytical exact solutions for these problems are not known. Following Dias and Vanden Broeck [6], we computed numerically the solutions via a series truncation method. These solutions depend on two parameters: the Weber number $\\alpha$ characterizing the strength of the surface tension and the angle $\\beta$ at the base characterizing the shape of the apex. Although free surface flows with surface tension admit capillary waves, it is found that solution exist only for values of the Weber number greater than $\\alpha_0$ for different configurations of the triangular obstacle.

  5. Near-Surface Geophysical Mapping of the Hydrological Response to an Intense Rainfall Event at the Field Scale

    Science.gov (United States)

    Martínez, G.; Vanderlinden, K.; Giraldez, J. V.; Espejo, A. J.; Muriel, J. L.

    2009-12-01

    Soil moisture plays an important role in a wide variety of biogeochemical fluxes in the soil-plant-atmosphere system and governs the (eco)hydrological response of a catchment to an external forcing such as rainfall. Near-surface electromagnetic induction (EMI) sensors that measure the soil apparent electrical conductivity (ECa) provide a fast and non-invasive means for characterizing this response at the field or catchment scale through high-resolution time-lapse mapping. Here we show how ECa maps, obtained before and after an intense rainfall event of 125 mm h-1, elucidate differences in soil moisture patterns and hydrologic response of an experimental field as a consequence of differed soil management. The dryland field (Vertisol) was located in SW Spain and cropped with a typical wheat-sunflower-legume rotation. Both, near-surface and subsurface ECa (ECas and ECad, respectively), were measured using the EM38-DD EMI sensor in a mobile configuration. Raw ECa measurements and Mean Relative Differences (MRD) provided information on soil moisture patterns while time-lapse maps were used to evaluate the hydrologic response of the field. ECa maps of the field, measured before and after the rainfall event showed similar patterns. The field depressions where most of water and sediments accumulated had the highest ECa and MRD values. The SE-oriented soil, which was deeper and more exposed to sun and wind, showed the lowest ECa and MRD. The largest differences raised in the central part of the field where a high ECa and MRD area appeared after the rainfall event as a consequence of the smaller soil depth and a possible subsurface flux concentration. Time-lapse maps of both ECa and MRD were also similar. The direct drill plots showed higher increments of ECa and MRD as a result of the smaller runoff production. Time-lapse ECa increments showed a bimodal distribution differentiating clearly the direct drill from the conventional and minimum tillage plots. However this kind

  6. Investigation of Relationship Between Hydrologic Processes of Precipitation, Evaporation and Stream Flow Using Linear Time Series Models (Case study: Western Basins of Lake Urmia

    Directory of Open Access Journals (Sweden)

    M. Moravej

    2016-02-01

    Full Text Available Introduction: Studying the hydrological cycle, especially in large scales such as water catchments, is difficult and complicated despite the fact that the numbers of hydrological components are limited. This complexity rises from complex interactions between hydrological components and environment. Recognition, determination and modeling of all interactive processes are needed to address this issue, but it's not feasible for dealing with practical engineering problems. So, it is more convenient to consider hydrological components as stochastic phenomenon, and use stochastic models for modeling them. Stochastic simulation of time series models related to water resources, particularly hydrologic time series, have been widely used in recent decades in order to solve issues pertaining planning and management of water resource systems. In this study time series models fitted to the precipitation, evaporation and stream flow series separately and the relationships between stream flow and precipitation processes are investigated. In fact, the three mentioned processes should be modeled in parallel to each other in order to acquire a comprehensive vision of hydrological conditions in the region. Moreover, the relationship between the hydrologic processes has been mostly studied with respect to their trends. It is desirable to investigate the relationship between trends of hydrological processes and climate change, while the relationship of the models has not been taken into consideration. The main objective of this study is to investigate the relationship between hydrological processes and their effects on each other and the selected models. Material and Method: In the current study, the four sub-basins of Lake Urmia Basin namely Zolachay (A, Nazloochay (B, Shahrchay (C and Barandoozchay (D were considered. Precipitation, evaporation and stream flow time series were modeled by linear time series. Fundamental assumptions of time series analysis namely

  7. Turbulent flow over an interactive alternating land-water surface

    Science.gov (United States)

    Van Heerwaarden, C.; Mellado, J. P.

    2014-12-01

    The alternating land-water surface is a challenging surface to represent accurately in weather and climate models, but it is of great importance for the surface energy balance in polar regions. The complexity of this surface lies in the fact that secondary circulations, which form at the boundary of water and land, interact strongly with the surface energy balance. Due to its large heat capacity, the water temperature adapts slowly to the flow, thus the properties of the atmosphere determine the uptake of energy from the water. In order to study this complex system in a simpler way, retaining only the most essential physics, we have simplified the full surface energy balance including radiation. We have derived a boundary condition that mimics the full balance and can be formulated as a so-called Robin boundary condition: a linear combination of Dirichlet (fixed temperature) and Neumann (fixed temperature gradient) ones. By spatially varying the coefficients, we are able to express land and water using this boundary condition. We have done a series of direct numerical simulations in which we generate artificial land-water patterns from noise created from a Gaussian spectrum centered around a dominant wave number. This method creates realistic random patterns, but we are still in control of the length scales. We show that the system can manifest itself in three regimes: micro-, meso- and macro-scale. In the micro-scale, we find perfect mixing of the near-surface atmosphere that results in identical air properties over water and land. In the meso-scale, secondary circulations alter the heat exchange considerably by advecting air between land and water. In addition, they bring the surface temperature of the land closer to that of the air, thereby modulating the energy loss due to outgoing longwave radiation. In the macro-scale regime, the flow over land and water become independent of each other and only the large scale forcings determine the energy balance.

  8. Rarefaction effects in gas flows over curved surfaces

    Science.gov (United States)

    Dongari, Nishanth; White, Craig; Scanlon, Thomas J.; Zhang, Yonghao; Reese, Jason M.

    2012-11-01

    The fundamental test case of gas flow between two concentric rotating cylinders is considered in order to investigate rarefaction effects associated with the Knudsen layers over curved surfaces. We carry out direct simulation Monte Carlo simulations covering a wide range of Knudsen numbers and accommodation coefficients, and for various outer-to-inner cylinder radius ratios. Numerical data is compared with classical slip flow theory and a new power-law (PL) wall scaling model. The PL model incorporates Knudsen layer effects in near-wall regions by taking into account the boundary limiting effects on the molecular free paths. The limitations of both theoretical models are explored with respect to rarefaction and curvature effects. Torque and velocity profile comparisons also convey that mere prediction of integral flow parameters does not guarantee the accuracy of a theoretical model, and that it is important to ensure that prediction of the local flowfield is in agreement with simulation data.

  9. Heat Transfer Enhancement in Turbulent Flows by Blocked Surfaces

    Directory of Open Access Journals (Sweden)

    Onur YEMENİCİ

    2013-04-01

    Full Text Available In this study, the heat transfer analyses over flat and blocked surfaces were carried out in turbulent flow under the influence of the block height. A constant-temperature hot wire anemometer was used to the velocity and turbulent intensity measurements, while temperature values were measured by copper-constantan thermocouples. The average Stanton numbers for block heights of 15 and 25 mm were higher than those of flat surface by %38 and %84, respectively. The results showed that the presence of the blocks increased the heat transfer and the enhancement rose with block heights

  10. Flow and heat transfer regimes during quenching of hot surfaces

    International Nuclear Information System (INIS)

    Barnea, Y.; Elias, E.

    1993-05-01

    Reflooding experiments have been performed to study flow and heat transfer regimes in a heated annular vertical channel under supercooled inlet conditions. A gamma densitometer was employed to determine the void fraction as a function of the distance from the quench front. Surface heat fluxes were determined by fast measurements of the temperature spatial distribution. Two quench front is shown to lie in the transition boiling region which spreads into the dry and wet segments of the heated surface. (authors) 5 refs, 3 figs

  11. Enhancement of a parsimonious water balance model to simulate surface hydrology in a glacierized watershed

    Science.gov (United States)

    Valentin, Melissa M.; Viger, Roland J.; Van Beusekom, Ashley E.; Hay, Lauren E.; Hogue, Terri S.; Foks, Nathan Leon

    2018-01-01

    The U.S. Geological Survey monthly water balance model (MWBM) was enhanced with the capability to simulate glaciers in order to make it more suitable for simulating cold region hydrology. The new model, MWBMglacier, is demonstrated in the heavily glacierized and ecologically important Copper River watershed in Southcentral Alaska. Simulated water budget components compared well to satellite‐based observations and ground measurements of streamflow, evapotranspiration, snow extent, and total water storage, with differences ranging from 0.2% to 7% of the precipitation flux. Nash Sutcliffe efficiency for simulated and observed streamflow was greater than 0.8 for six of eight stream gages. Snow extent matched satellite‐based observations with Nash Sutcliffe efficiency values of greater than 0.89 in the four Copper River ecoregions represented. During the simulation period 1949 to 2009, glacier ice melt contributed 25% of total runoff, ranging from 12% to 45% in different tributaries, and glacierized area was reduced by 6%. Statistically significant (p < 0.05) decreasing and increasing trends in annual glacier mass balance occurred during the multidecade cool and warm phases of the Pacific Decadal Oscillation, respectively, reinforcing the link between climate perturbations and glacier mass balance change. The simulations of glaciers and total runoff for a large, remote region of Alaska provide useful data to evaluate hydrologic, cryospheric, ecologic, and climatic trends. MWBM glacier is a valuable tool to understand when, and to what extent, streamflow may increase or decrease as glaciers respond to a changing climate.

  12. Preliminary results of hydrologic testing: The composite Umtanum basalt flow top at borehole RRL-2 (3,568 - 3,781 feet)

    International Nuclear Information System (INIS)

    Strait, S.R.; Spane, F.A. Jr.

    1982-11-01

    This report presents preliminary results and description of hydrologic test activities for the composite Umtanum basalt flow top (3,568--3,781 feet) at Borehole RRL-2. Hydrologic tests conducted include two constant discharge air-lift and four slug tests. Preliminary results indicate an observed hydraulic head for the test interval of 405.7 feet above mean sea level. Transmissivity values determined from hydrologic tests performed, range between 244 to 481 ft 2 /day, with an assigned best estimate of 480 ft 2 /day. The best estimate of equivalent hydraulic conductivity, based on an effective test thickness of 157 feet, is 3.1 ft/day. 7 refs., 9 figs., 3 tabs

  13. netherland hydrological modeling instrument

    Science.gov (United States)

    Hoogewoud, J. C.; de Lange, W. J.; Veldhuizen, A.; Prinsen, G.

    2012-04-01

    Netherlands Hydrological Modeling Instrument A decision support system for water basin management. J.C. Hoogewoud , W.J. de Lange ,A. Veldhuizen , G. Prinsen , The Netherlands Hydrological modeling Instrument (NHI) is the center point of a framework of models, to coherently model the hydrological system and the multitude of functions it supports. Dutch hydrological institutes Deltares, Alterra, Netherlands Environmental Assessment Agency, RWS Waterdienst, STOWA and Vewin are cooperating in enhancing the NHI for adequate decision support. The instrument is used by three different ministries involved in national water policy matters, for instance the WFD, drought management, manure policy and climate change issues. The basis of the modeling instrument is a state-of-the-art on-line coupling of the groundwater system (MODFLOW), the unsaturated zone (metaSWAP) and the surface water system (MOZART-DM). It brings together hydro(geo)logical processes from the column to the basin scale, ranging from 250x250m plots to the river Rhine and includes salt water flow. The NHI is validated with an eight year run (1998-2006) with dry and wet periods. For this run different parts of the hydrology have been compared with measurements. For instance, water demands in dry periods (e.g. for irrigation), discharges at outlets, groundwater levels and evaporation. A validation alone is not enough to get support from stakeholders. Involvement from stakeholders in the modeling process is needed. There fore to gain sufficient support and trust in the instrument on different (policy) levels a couple of actions have been taken: 1. a transparent evaluation of modeling-results has been set up 2. an extensive program is running to cooperate with regional waterboards and suppliers of drinking water in improving the NHI 3. sharing (hydrological) data via newly setup Modeling Database for local and national models 4. Enhancing the NHI with "local" information. The NHI is and has been used for many

  14. The progress of hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Chow, V T [University of Illinois, Urbana, IL (United States)

    1967-05-15

    This paper discusses mainly the challenge of hydrology, recent activities, events, and major problems in hydrology, and advances in hydrological techniques. New scientific knowledge and techniques developed in many modern scientific disciplines, and the recognition of the importance of hydrology in water-resources development enable and encourage the hydrologist to advance scientific hydrology. Many programmes to promote hydrology and to expand its attendant activities have been developed in recent years. Therefore, the activities in the United States of America, such as the Universities Council on Water Resources and the President's Water for Peace Programme, and the programmes in the International Hydrological Decade are mentioned. The most important advance in theoretical hydrology is the development of a new concept of dynamic sequential systems for the hydrological cycle, thus creating new fields of systems, parametric, and stochastic hydrology. Modern scientific instrumentation provide the hydrologist with better tools for solving his problems. The most important of these, such as electronic computers, remote sensing, and nuclear techniques are discussed. Today various major problems, both theoretical and practical, face the hydrologist. Theoretical problems concern the basic understanding of hydrological systems and the mathematical simulation and physical interpretation of hydrological phenomena. Major practical problems are numerous and diversified, but they are mostly related to the multiple-purpose development of water resources. Four central problematical subjects are discussed; namely, the effects of man on his environment, the dynamics of aqueous flow systems, hydrological transport mechanism, and groundwater hydrology. Also, the use of nuclear techniques in solving various hydrological problems is discussed. It is believed that the application of nuclear techniques would prove extremely valuable in helping solve problems, but their ultimate use in

  15. The progress of hydrology

    International Nuclear Information System (INIS)

    Chow, V.T.

    1967-01-01

    This paper discusses mainly the challenge of hydrology, recent activities, events, and major problems in hydrology, and advances in hydrological techniques. New scientific knowledge and techniques developed in many modern scientific disciplines, and the recognition of the importance of hydrology in water-resources development enable and encourage the hydrologist to advance scientific hydrology. Many programmes to promote hydrology and to expand its attendant activities have been developed in recent years. Therefore, the activities in the United States of America, such as the Universities Council on Water Resources and the President's Water for Peace Programme, and the programmes in the International Hydrological Decade are mentioned. The most important advance in theoretical hydrology is the development of a new concept of dynamic sequential systems for the hydrological cycle, thus creating new fields of systems, parametric, and stochastic hydrology. Modern scientific instrumentation provide the hydrologist with better tools for solving his problems. The most important of these, such as electronic computers, remote sensing, and nuclear techniques are discussed. Today various major problems, both theoretical and practical, face the hydrologist. Theoretical problems concern the basic understanding of hydrological systems and the mathematical simulation and physical interpretation of hydrological phenomena. Major practical problems are numerous and diversified, but they are mostly related to the multiple-purpose development of water resources. Four central problematical subjects are discussed; namely, the effects of man on his environment, the dynamics of aqueous flow systems, hydrological transport mechanism, and groundwater hydrology. Also, the use of nuclear techniques in solving various hydrological problems is discussed. It is believed that the application of nuclear techniques would prove extremely valuable in helping solve problems, but their ultimate use in

  16. 3D surface reconstruction using optical flow for medical imaging

    International Nuclear Information System (INIS)

    Weng, Nan; Yang, Yee-Hong; Pierson, R.

    1996-01-01

    The recovery of a 3D model from a sequence of 2D images is very useful in medical image analysis. Image sequences obtained from the relative motion between the object and the camera or the scanner contain more 3D information than a single image. Methods to visualize the computed tomograms can be divided into two approaches: the surface rendering approach and the volume rendering approach. A new surface rendering method using optical flow is proposed. Optical flow is the apparent motion in the image plane produced by the projection of the real 3D motion onto 2D image. In this paper, the object remains stationary while the scanner undergoes translational motion. The 3D motion of an object can be recovered from the optical flow field using additional constraints. By extracting the surface information from 3D motion, it is possible to get an accurate 3D model of the object. Both synthetic and real image sequences have been used to illustrate the feasibility of the proposed method. The experimental results suggest that the proposed method is suitable for the reconstruction of 3D models from ultrasound medical images as well as other computed tomograms

  17. Water surface elevation from the upcoming SWOT mission under different flows conditions

    Science.gov (United States)

    Domeneghetti, Alessio; Schumann, Guy J. P.; Wei, Rui; Frasson, Renato P. M.; Durand, Michael; Pavelsky, Tamlin; Castellarin, Attilio; Brath, Armando

    2017-04-01

    The upcoming SWOT (Surface Water and Ocean Topography) satellite mission will provide unprecedented bi-dimensional observations of terrestrial water surface heights along rivers wider than 100m. Despite the literature reports several activities showing possible uses of SWOT products, potential and limitations of satellite observations still remain poorly understood and investigated. We present one of the first analyses regarding the spatial observation of water surface elevation expected from SWOT for a 140 km reach of the middle-lower portion of the Po River, in Northern Italy. The river stretch is characterized by a main channel varying from 100-500 m in width and a floodplain delimited by a system of major embankments that can be as wide as 5 km. The reconstruction of the hydraulic behavior of the Po River is performed by means of a quasi-2D model built with detailed topographic and bathymetric information (LiDAR, 2m resolution), while the simulation of remotely sensed hydrometric data is performed with a SWOT simulator that mimics the satellite sensor characteristics. Referring to water surface elevations associated with different flow conditions (maximum, minimum and average flow) this work characterizes the spatial observations provided by SWOT and highlights the strengths and limitations of the expected products. The analysis provides a robust reference for spatial water observations that will be available from SWOT and assesses possible effects of river embankments, river width and river topography under different hydraulic conditions. Results of the study characterize the expected accuracy of the upcoming SWOT mission and provide additional insights towards the appropriate exploitation of future hydrological observations.

  18. Analyzing the Relative Linkages of Land Use and Hydrologic Variables with Urban Surface Water Quality using Multivariate Techniques

    Science.gov (United States)

    Ahmed, S.; Abdul-Aziz, O. I.

    2015-12-01

    We used a systematic data-analytics approach to analyze and quantify relative linkages of four stream water quality indicators (total nitrogen, TN; total phosphorus, TP; chlorophyll-a, Chla; and dissolved oxygen, DO) with six land use and four hydrologic variables, along with the potential external (upstream in-land and downstream coastal) controls in highly complex coastal urban watersheds of southeast Florida, U.S.A. Multivariate pattern recognition techniques of principle component and factor analyses, in concert with Pearson correlation analysis, were applied to map interrelations and identify latent patterns of the participatory variables. Relative linkages of the in-stream water quality variables with their associated drivers were then quantified by developing dimensionless partial least squares (PLS) regression model based on standardized data. Model fitting efficiency (R2=0.71-0.87) and accuracy (ratio of root-mean-square error to the standard deviation of the observations, RSR=0.35-0.53) suggested good predictions of the water quality variables in both wet and dry seasons. Agricultural land and groundwater exhibited substantial controls on surface water quality. In-stream TN concentration appeared to be mostly contributed by the upstream water entering from Everglades in both wet and dry seasons. In contrast, watershed land uses had stronger linkages with TP and Chla than that of the watershed hydrologic and upstream (Everglades) components for both seasons. Both land use and hydrologic components showed strong linkages with DO in wet season; however, the land use linkage appeared to be less in dry season. The data-analytics method provided a comprehensive empirical framework to achieve crucial mechanistic insights into the urban stream water quality processes. Our study quantitatively identified dominant drivers of water quality, indicating key management targets to maintain healthy stream ecosystems in complex urban-natural environments near the coast.

  19. Effects of surface-water and groundwater inflows and outflows on the hydrology of the Tsala Apopka Lake Basin in Citrus County, Florida

    Science.gov (United States)

    Sepúlveda, Nicasio; Fulkerson, Mark; Basso, Ron; Ryan, Patrick J.

    2018-05-21

    The U.S. Geological Survey, in cooperation with the Southwest Florida Water Management District, initiated a study to quantify the inflows and outflows in the Floral City, Inverness, and Hernando pools of the Tsala Apopka Lake Basin in Citrus County, Florida. This study assesses hydrologic changes in pool stages, groundwater levels, spring flows, and streamflows caused by the diversion of streamflow from the Withlacoochee River to the Tsala Apopka Lake Basin through water-control structures. A surface-water/groundwater flow model was developed using hydraulic parameters for lakes, streams, the unsaturated zone, and the underlying surficial and Upper Floridan aquifers estimated using an inverse modeling calibration technique. After calibration, the model was used to assess the relation between inflows and outflows in the Tsala Apopka Lake Basin and changes in pool stages.Simulation results using the calibrated surface-water/groundwater flow model showed that leakage rates from the pools to the Upper Floridan aquifer were largest at the deep lake cells and that these leakage rates to the Upper Floridan aquifer were the highest in the model area. Downward leakage to the Upper Floridan aquifer occurred beneath most of the extent of the Floral City, Inverness, and Hernando pools. These leakage rates depended on the lakebed leakance and the difference between lake stages and heads in the Upper Floridan aquifer. Leakage rates were higher for the Floral City pool than for the Inverness pool, and higher for the Inverness pool than for the Hernando pool. Lakebed leakance was higher for the Floral City pool than for the Hernando pool, and higher for the Hernando pool than for the Inverness pool.Simulation results showed that the average recharge rate to the surficial aquifer was 10.3 inches per year for the 2004 to 2012 simulation period. Areas that recharge the surficial aquifer covered about 86 percent of the model area. Simulations identified areas along segments of the

  20. Nutrients and Hydrology Indicate the Driving Mechanisms of Peatland Surface Patterning

    NARCIS (Netherlands)

    Eppinga, M.B.; Ruiter, de P.C.; Wassen, M.J.; Rietkerk, M.

    2009-01-01

    Peatland surface patterning motivates studies that identify underlying structuring mechanisms. Theoretical studies so far suggest that different mechanisms may drive similar types of patterning. The long time span associated with peatland surface pattern formation, however, limits possibilities for

  1. Land Surface Model (LSM 1.0) for Ecological, Hydrological, Atmospheric Studies

    Data.gov (United States)

    National Aeronautics and Space Administration — The NCAR LSM 1.0 is a land surface model developed to examine biogeophysical and biogeochemical land-atmosphere interactions, especially the effects of land surfaces...

  2. Simulating Hydrologic Flow and Reactive Transport with PFLOTRAN and PETSc on Emerging Fine-Grained Parallel Computer Architectures

    Science.gov (United States)

    Mills, R. T.; Rupp, K.; Smith, B. F.; Brown, J.; Knepley, M.; Zhang, H.; Adams, M.; Hammond, G. E.

    2017-12-01

    As the high-performance computing community pushes towards the exascale horizon, power and heat considerations have driven the increasing importance and prevalence of fine-grained parallelism in new computer architectures. High-performance computing centers have become increasingly reliant on GPGPU accelerators and "manycore" processors such as the Intel Xeon Phi line, and 512-bit SIMD registers have even been introduced in the latest generation of Intel's mainstream Xeon server processors. The high degree of fine-grained parallelism and more complicated memory hierarchy considerations of such "manycore" processors present several challenges to existing scientific software. Here, we consider how the massively parallel, open-source hydrologic flow and reactive transport code PFLOTRAN - and the underlying Portable, Extensible Toolkit for Scientific Computation (PETSc) library on which it is built - can best take advantage of such architectures. We will discuss some key features of these novel architectures and our code optimizations and algorithmic developments targeted at them, and present experiences drawn from working with a wide range of PFLOTRAN benchmark problems on these architectures.

  3. Isotopes in hydrology of ground water

    International Nuclear Information System (INIS)

    Rodriguez, N.; C, O.

    1996-01-01

    Fundamental concepts on Radioactivity, Isotopes, Radioisotopes, Law of Nuclear Decay (Middle Life concept), Radioactivity units, Types of radiation, Absorption and dispersion of both Alfa and Beta particles and both gamma and X-rays attenuation are presented. A description on Environmental Isotopes (those that are presented in natural form in the environment and those that can't be controlled by the humans), both stables and unstable (radioisotopes) isotopes is made. Isotope hydrology applications in surface water investigations as: Stream flow measurements and Atmosphere - surface waters interrelationship is described. With relation to the groundwater investigations, different applications of the isotope hydrology, its theoretical base and its methodology are presented to each one of the substrates as: Unsaturated zone (soil cape), Saturated zone (aquifer cape), Surface waters - ground waters interrelationship (infiltration and recharge) and to hydrologic balance

  4. Hydrologic issues in repository siting

    International Nuclear Information System (INIS)

    Remson, I.; Gorelick, S.M.

    1982-01-01

    Extrapolation of Darcy's law to the transport of water an solutes in unfractured poorly permeable rocks being studied for nuclear waste disposal is questioned. The hydrologic literature includes numerous references to both non-Darcian flow in dense materials devoid of macrofractures and microfractures and to threshold gradients below which no flow occurs. For such situations to occur, the pore-size range must be small enough so that all pore water is sufficiently close to mineral surfaces to be affected by the surficial forces. Then the flow will be non-Newtonian and non-Darcian, and solute transport will be by molecular diffusion. If fluid transport in very dense unfractured rocks is non-Darcian, useful methods of testing candidate host rocks become apparent. In situ nondestructive pressure testing of canister waste emplacement boreholes in a mined repository can verify the absence of both fracture flow and Darcian flow. 18 references

  5. Compilation of geologic, hydrologic, and ground-water flow modeling information for the Spokane Valley-Rathdrum Prairie aquifer, Spokane County, Washington, and Bonner and Kootenai Counties, Idaho

    Science.gov (United States)

    Kahle, Sue C.; Caldwell, Rodney R.; Bartolino, James R.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources and Washington Department of Ecology compiled and described geologic, hydrologic, and ground-water flow modeling information about the Spokane Valley-Rathdrum Prairie (SVRP) aquifer in northern Idaho and northeastern Washington. Descriptions of the hydrogeologic framework, water-budget components, ground- and surface-water interactions, computer flow models, and further data needs are provided. The SVRP aquifer, which covers about 370 square miles including the Rathdrum Prairie, Idaho and the Spokane valley and Hillyard Trough, Washington, was designated a Sole Source Aquifer by the U.S. Environmental Protection Agency in 1978. Continued growth, water management issues, and potential effects on water availability and water quality in the aquifer and in the Spokane and Little Spokane Rivers have illustrated the need to better understand and manage the region's water resources. The SVRP aquifer is composed of sand, gravel, cobbles, and boulders primarily deposited by a series of catastrophic glacial outburst floods from ancient Glacial Lake Missoula. The material deposited in this high-energy environment is coarser-grained than is typical for most basin-fill deposits, resulting in an unusually productive aquifer with well yields as high as 40,000 gallons per minute. In most places, the aquifer is bounded laterally by bedrock composed of granite, metasedimentary rocks, or basalt. The lower boundary of the aquifer is largely unknown except along the margins or in shallower parts of the aquifer where wells have penetrated its entire thickness and reached bedrock or silt and clay deposits. Based on surface geophysics, the thickness of the aquifer is about 500 ft near the Washington-Idaho state line, but more than 600 feet within the Rathdrum Prairie and more than 700 feet in the Hillyard trough based on drilling records. Depth to water in the aquifer is greatest in the northern

  6. Hydrology and modeling of flow conditions at Bridge 339 and Mile 38-43, Copper River Highway, Alaska

    Science.gov (United States)

    Brabets, Timothy P.

    2012-01-01

    The Copper River basin, the sixth largest watershed in Alaska, drains an area of 24,200 square miles in south-central Alaska. This large, glacier-fed river flows across a wide alluvial fan before it enters the Gulf of Alaska. The Copper River Highway, which traverses the alluvial fan, has been affected by channel planform reconfiguration. Currently (2012), two areas of the Copper River Highway are at risk: at Mile 38-43, the road grade is too low and the highway could be flooded by high flows of the Copper River, and at Mile 36, the main channel of the Copper River has migrated directly toward Bridge 339. Because Bridge 339 was not designed and built to convey the main flow of the Copper River, as much as 50 feet of scour occurred at the piers in 2011. The piers can no longer absorb the lateral or vertical loads, resulting in closure of the bridge and the Copper River Highway. The U.S. Geological Survey Flow and Sediment Transport with Morphologic Evolution of Channels (FaSTMECH) model was used to simulate the flow of the Copper River and produce simulations of depth, water-surface elevation, and velocity. At the Mile 38-43 area, FaSTMECH was used to analyze the effects of raising the road grade 5 feet, and at Mile 36, FaSTMECH was used to analyze the effects of constructing a channel to divert flow away from Bridge 339. Results from FaSTMECH indicate that if raising the road grade 5 feet in the Mile 38-43 area, a flood with an annual exceedance probability of 2 percent (400,000 cubic feet per second) would not overtop the highway. In the Bridge 339 area, results from FaSTMECH indicate that a design channel could divert flows as much as 100,000 cubic feet per second away from Bridge 339.

  7. Application of FTLOADDS to Simulate Flow, Salinity, and Surface-Water Stage in the Southern Everglades, Florida

    Science.gov (United States)

    Wang, John D.; Swain, Eric D.; Wolfert, Melinda A.; Langevin, Christian D.; James, Dawn E.; Telis, Pamela A.

    2007-01-01

    The Comprehensive Everglades Restoration Plan requires numerical modeling to achieve a sufficient understanding of coastal freshwater flows, nutrient sources, and the evaluation of management alternatives to restore the ecosystem of southern Florida. Numerical models include a regional water-management model to represent restoration changes to the hydrology of southern Florida and a hydrodynamic model to represent the southern and western offshore waters. The coastal interface between these two systems, however, has complex surface-water/ground-water and freshwater/saltwater interactions and requires a specialized modeling effort. The Flow and Transport in a Linked Overland/Aquifer Density Dependent System (FTLOADDS) code was developed to represent connected surface- and ground-water systems with variable-density flow. The first use of FTLOADDS is the Southern Inland and Coastal Systems (SICS) application to the southeastern part of the Everglades/Florida Bay coastal region. The need to (1) expand the domain of the numerical modeling into most of Everglades National Park and the western coastal area, and (2) better represent the effect of water-delivery control structures, led to the application of the FTLOADDS code to the Tides and Inflows in the Mangroves of the Everglades (TIME) domain. This application allows the model to address a broader range of hydrologic issues and incorporate new code modifications. The surface-water hydrology is of primary interest to water managers, and is the main focus of this study. The coupling to ground water, however, was necessary to accurately represent leakage exchange between the surface water and ground water, which transfers substantial volumes of water and salt. Initial calibration and analysis of the TIME application produced simulated results that compare well statistically with field-measured values. A comparison of TIME simulation results to previous SICS results shows improved capabilities, particularly in the

  8. Entropy flow and generation in radiative transfer between surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.M.; Basu, S. [Georgia Institute of Technolgy, Atlanta, GA (United States). George W. Woodruff School of Mechanical Engineering

    2007-02-15

    Entropy of radiation has been used to derive the laws of blackbody radiation and determine the maximum efficiency of solar energy conversion. Along with the advancement in thermophotovoltaic technologies and nanoscale heat radiation, there is an urgent need to determine the entropy flow and generation in radiative transfer between nonideal surfaces when multiple reflections are significant. This paper investigates entropy flow and generation when incoherent multiple reflections are included, without considering the effects of interference and photon tunneling. The concept of partial equilibrium is applied to interpret the monochromatic radiation temperature of thermal radiation, T{sub l}(l,{omega}), which is dependent on both wavelength l and direction {omega}. The entropy flux and generation can thus be evaluated for nonideal surfaces. It is shown that several approximate expressions found in the literature can result in significant errors in entropy analysis even for diffuse-gray surfaces. The present study advances the thermodynamics of nonequilibrium thermal radiation and will have a significant impact on the future development of thermophotovoltaic and other radiative energy conversion devices. (author)

  9. Comparison of Surface Flow Features from Lidar-Derived Digital Elevation Models with Historical Elevation and Hydrography Data for Minnehaha County, South Dakota

    Science.gov (United States)

    Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.

    2009-01-01

    The U.S. Geological Survey (USGS) has taken the lead in the creation of a valuable remote sensing product by incorporating digital elevation models (DEMs) derived from Light Detection and Ranging (lidar) into the National Elevation Dataset (NED), the elevation layer of 'The National Map'. High-resolution lidar-derived DEMs provide the accuracy needed to systematically quantify and fully integrate surface flow including flow direction, flow accumulation, sinks, slope, and a dense drainage network. In 2008, 1-meter resolution lidar data were acquired in Minnehaha County, South Dakota. The acquisition was a collaborative effort between Minnehaha County, the city of Sioux Falls, and the USGS Earth Resources Observation and Science (EROS) Center. With the newly acquired lidar data, USGS scientists generated high-resolution DEMs and surface flow features. This report compares lidar-derived surface flow features in Minnehaha County to 30- and 10-meter elevation data previously incorporated in the NED and ancillary hydrography datasets. Surface flow features generated from lidar-derived DEMs are consistently integrated with elevation and are important in understanding surface-water movement to better detect surface-water runoff, flood inundation, and erosion. Many topographic and hydrologic applications will benefit from the increased availability of accurate, high-quality, and high-resolution surface-water data. The remotely sensed data provide topographic information and data integration capabilities needed for meeting current and future human and environmental needs.

  10. Examination of the effect of blowing on the near-surface flow structure over a dimpled surface

    Science.gov (United States)

    Borchetta, C. G.; Martin, A.; Bailey, S. C. C.

    2018-03-01

    The near surface flow over a dimpled surface with flow injection through it was documented using time-resolved particle image velocimetry. The instantaneous flow structure, time-averaged statistics, and results from snapshot proper orthogonal decomposition were used to examine the coherent structures forming near the dimpled surface. In particular, the modifications made to the flow structures by the addition of flow injection through the surface were studied. It was observed that without flow injection, inclined flow structures with alternating vorticity from neighboring dimples are generated by the dimples and advect downstream. This behavior is coupled with fluid becoming entrained inside the dimples, recirculating and ejecting away from the surface. When flow injection was introduced through the surface, the flow structures became more disorganized, but some of the features of the semi-periodic structures observed without flow injection were preserved. The structures with flow injection appear in multiple wall-normal layers, formed from vortical structures shed from upstream dimples, with a corresponding increase in the size of the advecting structures. As a result of the more complex flow field observed with flow injection, there was an increase in turbulent kinetic energy and Reynolds shear stress, with the Reynolds shear stress representing an increase in vertical transport of momentum by sweeping and ejecting motions that were not present without flow injection.

  11. Potentiometric Surface of the Alluvial Aquifer and Hydrologic Conditions in the Juana Diaz area, Puerto Rico, June 29 - July 1, 2005

    Science.gov (United States)

    Rodriguez, Jose M.; Santigo-Rivera, Luis; Gómez-Gómez, Fernando

    2006-01-01

    A synoptic survey of the hydrologic conditions in the Juana Diaz area, Puerto Rico, was conducted between June 29 and July 1, 2005, to define the spatial distribution of the potentiometric surface of the alluvial aquifer. The study area encompasses 21 square miles of the more extensive South Coastal Plain Alluvial Aquifer system and is bounded along the north by foothills of the Cordillera Central mountain chain, to the south by the Caribbean Sea, the east by the Rio Descalabrado and to the west by the Rio Inabon. Ground water in the Juana Diaz area is in the Quaternary-age alluvial deposits and the middle-Tertiary age Ponce Limestone and Juana Diaz Formation (Giusti, 1968). The hydraulic properties of the Ponce Limestone in the Juana Diaz area are unknown, and the Juana Diaz Formation is a unit of poor permeability due to its high clay content. Consequently, the Ponce Limestone and the Juana Diaz Formation are generally considered to be the base of the alluvial aquifer in the Juana Diaz area with ground-water flow occurring primarily within the alluvial deposits. The potentiometric-surface map of the alluvial aquifer was delineated using ground-water level measurements taken at existing wells. The water-level measurements were taken at wells that were either not pumping during the survey or were shut down for a brief period. In the latter case, a recovery period of 30 minutes was allowed for the drawdown in the wellbore to achieve a near static level position representative of the aquifer at the measurement point. Land-surface altitude from U.S. Geological Survey (USGS) 1:20,000 scale topographic maps (Playa de Ponce, Ponce, Rio Descalabrado, and Santa Isabel) were used to refer ground-water levels to mean sea level datum (National Geodetic Vertical Datum of 1929). In addition to the ground-water level measurements, the potentiometricsurface contours were delineated using hydrologic features, such as drainage ditches and saturated intermittent streams that were

  12. Measurement of flow and direction of ground water by radioactive tracers: hydrological evaluation of a waste disposal site at 'Instituto de Pesquisas Energeticas e Nucleares (IPEN)'

    International Nuclear Information System (INIS)

    Chandra, U.; Aoki, P.E.; Ramos e Silva, J.A.; Castagnet, A.C.G.

    1981-05-01

    The method of determining flow and drection of ground water by using radioactive tracers in ground water borings is described. Various parameters controlling the measurements are discussed in detail. Application of the method in studying a variety of geohydrological problems, in view of the hydrological evaluation of the waste disposal site at IPEN, is indicated. Comparison of the method with conventional pumping tests is made. (I.C.R.) [pt

  13. Calibration of a distributed hydrology and land surface model using energy flux measurements

    DEFF Research Database (Denmark)

    Larsen, Morten Andreas Dahl; Refsgaard, Jens Christian; Jensen, Karsten H.

    2016-01-01

    In this study we develop and test a calibration approach on a spatially distributed groundwater-surface water catchment model (MIKE SHE) coupled to a land surface model component with particular focus on the water and energy fluxes. The model is calibrated against time series of eddy flux measure...

  14. Characterizing water surface elevation under different flow conditions for the upcoming SWOT mission

    Science.gov (United States)

    Domeneghetti, A.; Schumann, G. J.-P.; Frasson, R. P. M.; Wei, R.; Pavelsky, T. M.; Castellarin, A.; Brath, A.; Durand, M. T.

    2018-06-01

    The Surface Water and Ocean Topography satellite mission (SWOT), scheduled for launch in 2021, will deliver two-dimensional observations of water surface heights for lakes, rivers wider than 100 m and oceans. Even though the scientific literature has highlighted several fields of application for the expected products, detailed simulations of the SWOT radar performance for a realistic river scenario have not been presented in the literature. Understanding the error of the most fundamental "raw" SWOT hydrology product is important in order to have a greater awareness about strengths and limits of the forthcoming satellite observations. This study focuses on a reach (∼140 km in length) of the middle-lower portion of the Po River, in Northern Italy, and, to date, represents one of the few real-case analyses of the spatial patterns in water surface elevation accuracy expected from SWOT. The river stretch is characterized by a main channel varying from 100 to 500 m in width and a large floodplain (up to 5 km) delimited by a system of major embankments. The simulation of the water surface along the Po River for different flow conditions (high, low and mean annual flows) is performed with inputs from a quasi-2D model implemented using detailed topographic and bathymetric information (LiDAR, 2 m resolution). By employing a simulator that mimics many SWOT satellite sensor characteristics and generates proxies of the remotely sensed hydrometric data, this study characterizes the spatial observations potentially provided by SWOT. We evaluate SWOT performance under different hydraulic conditions and assess possible effects of river embankments, river width, river topography and distance from the satellite ground track. Despite analyzing errors from the raw radar pixel cloud, which receives minimal processing, the present study highlights the promising potential of this Ka-band interferometer for measuring water surface elevations, with mean elevation errors of 0.1 cm and 21

  15. Effect of non-equilibrium flow chemistry and surface catalysis on surface heating to AFE

    Science.gov (United States)

    Stewart, David A.; Henline, William D.; Chen, Yih-Kanq

    1991-01-01

    The effect of nonequilibrium flow chemistry on the surface temperature distribution over the forebody heat shield on the Aeroassisted Flight Experiment (AFE) vehicle was investigated using a reacting boundary-layer code. Computations were performed by using boundary-layer-edge properties determined from global iterations between the boundary-layer code and flow field solutions from a viscous shock layer (VSL) and a full Navier-Stokes solution. Surface temperature distribution over the AFE heat shield was calculated for two flight conditions during a nominal AFE trajectory. This study indicates that the surface temperature distribution is sensitive to the nonequilibrium chemistry in the shock layer. Heating distributions over the AFE forebody calculated using nonequilibrium edge properties were similar to values calculated using the VSL program.

  16. Land Use Management in the Panama Canal Watershed to Maximize Hydrologic Ecosystem Services Benefits: Explicit Simulation of Preferential Flow Paths in an HPC Environment

    Science.gov (United States)

    Regina, J. A.; Ogden, F. L.; Steinke, R. C.; Frazier, N.; Cheng, Y.; Zhu, J.

    2017-12-01

    Preferential flow paths (PFP) resulting from biotic and abiotic factors contribute significantly to the generation of runoff in moist lowland tropical watersheds. Flow through PFPs represents the dominant mechanism by which land use choices affect hydrological behavior. The relative influence of PFP varies depending upon land-use management practices. Assessing the possible effects of land-use and landcover change on flows, and other ecosystem services, in the humid tropics partially depends on adequate simulation of PFP across different land-uses. Currently, 5% of global trade passes through the Panama Canal, which is supplied with fresh water from the Panama Canal Watershed. A third set of locks, recently constructed, are expected to double the capacity of the Canal. We incorporated explicit simulation of PFPs in to the ADHydro HPC distributed hydrological model to simulate the effects of land-use and landcover change due to land management incentives on water resources availability in the Panama Canal Watershed. These simulations help to test hypotheses related to the effectiveness of various proposed payments for ecosystem services schemes. This presentation will focus on hydrological model formulation and performance in an HPC environment.

  17. Flux surface shaping effects on tokamak edge turbulence and flows

    International Nuclear Information System (INIS)

    Kendl, A.; Scott, B.D.

    2004-01-01

    The influence of shaping of magnetic flux surfaces in tokamaks on gyro-fluid edge turbulence is studied numerically. Magnetic field shaping in tokamaks is mainly due to elongation, triangularity, shift and the presence of a divertor X-point. A series of tokamak configurations with varying elongation 1 ≤ κ ≥ 2 and triangularity 0 ≤ δ ≤ 0.4, and an actual ASDEX Upgrade divertor configuration are obtained with the equilibrium code HELENA and implemented into the gyro-fluid turbulence code GEM. The study finds minimal impact on the zonal flow physics itself, but strong impact on the turbulence and transport. (authors)

  18. Flux surface shaping effects on tokamak edge turbulence and flows

    Energy Technology Data Exchange (ETDEWEB)

    Kendl, A. [Innsbruck Univ., Institut fuer Theoretische Physik, Association EURATOM (Austria); Scott, B.D. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching bei Muenchen (Germany)

    2004-07-01

    The influence of shaping of magnetic flux surfaces in tokamaks on gyro-fluid edge turbulence is studied numerically. Magnetic field shaping in tokamaks is mainly due to elongation, triangularity, shift and the presence of a divertor X-point. A series of tokamak configurations with varying elongation 1 {<=} {kappa} {>=} 2 and triangularity 0 {<=} {delta} {<=} 0.4, and an actual ASDEX Upgrade divertor configuration are obtained with the equilibrium code HELENA and implemented into the gyro-fluid turbulence code GEM. The study finds minimal impact on the zonal flow physics itself, but strong impact on the turbulence and transport. (authors)

  19. DIVERGENT HORIZONTAL SUB-SURFACE FLOWS WITHIN ACTIVE REGION 11158

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Kiran; Tripathy, S. C.; Hill, F., E-mail: kjain@nso.edu, E-mail: stripathy@nso.edu, E-mail: fhill@nso.edu [National Solar Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States)

    2015-07-20

    We measure the horizontal subsurface flow in a fast emerging active region (AR; NOAA 11158) using the ring-diagram technique and the Helioseismic and Magnetic Imager high spatial resolution Dopplergrams. This AR had a complex magnetic structure and displayed significant changes in morphology during its disk passage. Over a period of six days from 2011 February 11 to 16, the temporal variation in the magnitude of the total velocity is found to follow the trend of magnetic field strength. We further analyze regions of individual magnetic polarity within AR 11158 and find that the horizontal velocity components in these sub-regions have significant variation with time and depth. The leading and trailing polarity regions move faster than the mixed-polarity region. Furthermore, both zonal and meridional components have opposite signs for trailing and leading polarity regions at all depths showing divergent flows within the AR. We also find a sharp decrease in the magnitude of total horizontal velocity in deeper layers around major flares. It is suggested that the re-organization of magnetic fields during flares, combined with the sunspot rotation, decreases the magnitude of horizontal flows or that the flow kinetic energy has been converted into the energy released by flares. After the decline in flare activity and sunspot rotation, the flows tend to follow the pattern of magnetic activity. We also observe less variation in the velocity components near the surface but these tend to increase with depth, further demonstrating that the deeper layers are more affected by the topology of ARs.

  20. Correlations of Surface Deformation and 3D Flow Field in a Compliant Wall Turbulent Channel Flow.

    Science.gov (United States)

    Wang, Jin; Zhang, Cao; Katz, Joseph

    2015-11-01

    This study focuses on the correlations between surface deformation and flow features, including velocity, vorticity and pressure, in a turbulent channel flow over a flat, compliant Polydimethylsiloxane (PDMS) wall. The channel centerline velocity is 2.5 m/s, and the friction Reynolds number is 2.3x103. Analysis is based on simultaneous measurements of the time resolved 3D velocity and surface deformation using tomographic PIV and Mach-Zehnder Interferometry. The volumetric pressure distribution is calculated plane by plane by spatially integrating the material acceleration using virtual boundary, omni-directional method. Conditional sampling based on local high/low pressure and deformation events reveals the primary flow structures causing the deformation. High pressure peaks appear at the interface between sweep and ejection, whereas the negative deformations peaks (dent) appear upstream, under the sweeps. The persistent phase lag between flow and deformations are presumably caused by internal damping within the PDMS. Some of the low pressure peaks and strong ejections are located under the head of hairpin vortices, and accordingly, are associated with positive deformation (bump). Others bumps and dents are correlated with some spanwise offset large inclined quasi-streamwise vortices that are not necessarily associated with hairpins. Sponsored by ONR.

  1. Influence of lateral groundwater flow in a shallow aquifer on eco-hydrological process in a shrub-grass coexistence semiarid area

    Science.gov (United States)

    Wang, Siru; Sun, Jinhua; Lei, Huimin; Zhu, Qiande; Jiang, Sanyuan

    2017-04-01

    Topography has a considerable influence on eco-hydrological processes resulting from the patterns of solar radiation distribution and lateral water flow. However, not much quantitative information on the contribution of lateral groundwater flow on ecological processes such as vegetation growth and evapo-transpiration is available. To fill this gap, we used a simple eco-hydrological model based on water balance with a 3D groundwater module that uses Darcy's law. This model was applied to a non-contributing area of 50km2 dominated by grassland and shrubland with an underlying shallow aquifer. It was calibrated using manually and remotely sensed vegetation data and water flux data observed by eddy covariance system of two flux towers as well as water table data obtained from HOBO recorders of 40 wells. The results demonstrate that the maximum hydraulic gradient and the maximum flux of lateral groundwater flow reached to 0.156m m-1 and 0.093m3 s-1 respectively. The average annual maximum LAI in grassland, predominantly in low-lying areas, improved by about 5.9% while that in shrubland, predominantly in high-lying areas, remained the same when lateral groundwater flow is considered adequately compared to the case without considering lateral groundwater flow. They also show that LAI is positively and nonlinearly related to evapotranspiration, and that the greater the magnitude of evapotranspiration, the smaller the rate of increase of LAI. The results suggest that lateral groundwater flow should not be neglected when simulating eco-hydrological process in areas with a shallow aquifer.

  2. Topological Fluid Mechanics with Applications to Free Surfaces and Axisymmetric Flows

    DEFF Research Database (Denmark)

    Brøns, Morten

    1996-01-01

    Topological fluid mechanics is the study of qualitative features of fluid patterns. We discuss applications to the flow beneath a stagnant surface film, and to patterns in axisymmetric flow.......Topological fluid mechanics is the study of qualitative features of fluid patterns. We discuss applications to the flow beneath a stagnant surface film, and to patterns in axisymmetric flow....

  3. Turbulence modeling and surface heat transfer in a stagnation flow region

    Science.gov (United States)

    Wang, C. R.; Yeh, F. C.

    1987-01-01

    Analysis for the turbulent flow field and the effect of freestream turbulence on the surface heat transfer rate of a stagnation flow is presented. The emphasis is on modeling and its augmentation of surface heat transfer rate. The flow field considered is the region near the forward stagnation point of a circular cylinder in a uniform turbulent mean flow.

  4. Increase of body surface temperature and blood flow by theanine

    International Nuclear Information System (INIS)

    Hasegawa, Takeo; Noguchi, Kenichi; Ando, Satoshi

    2002-01-01

    Suntheanine (Taiyo Kagaku Co.: Theanine) is the trade name for L-theanine which is a unique amino acid found almost solely in tea plants, responsible for the exotictaste of green tea. We investigated the effects of relate to relaxation, improves the taste of processed foods, radiation sensitization, and increase of body surface temperature in vivo study. The results of the present study confirmed, (1) Suntheanine is incorporated into the brain and induces the emission of α -waves an induced of relaxation. (2) Body surface temperature and blood flow on skin were increased after administration of Suntheanine. (3) There was effects of radiation sensitization in whole body irradiation of X-rays after Suntheanine IP injection on C3H mice. (4) Acute toxicity, subacute toxicity and mutagen testconfirm the safety Suntheanine in this study

  5. Non-integrability of geodesic flow on certain algebraic surfaces

    International Nuclear Information System (INIS)

    Waters, T.J.

    2012-01-01

    This Letter addresses an open problem recently posed by V. Kozlov: a rigorous proof of the non-integrability of the geodesic flow on the cubic surface xyz=1. We prove this is the case using the Morales–Ramis theorem and Kovacic algorithm. We also consider some consequences and extensions of this result. -- Highlights: ► The behaviour of geodesics on surfaces defined by algebraic expressions is studied. ► The non-integrability of the geodesic equations is rigorously proved using differential Galois theory. ► Morales–Ramis theory and Kovacic's algorithm is used and the normal variational equation is of Fuchsian type. ► Some extensions and limitations are discussed.

  6. SIPSON--simulation of interaction between pipe flow and surface overland flow in networks.

    Science.gov (United States)

    Djordjević, S; Prodanović, D; Maksimović, C; Ivetić, M; Savić, D

    2005-01-01

    The new simulation model, named SIPSON, based on the Preissmann finite difference method and the conjugate gradient method, is presented in the paper. This model simulates conditions when the hydraulic capacity of a sewer system is exceeded, pipe flow is pressurized, the water flows out from the piped system to the streets, and the inlets cannot capture all the runoff. In the mathematical model, buried structures and pipelines, together with surface channels, make a horizontally and vertically looped network involving a complex interaction of flows. In this paper, special internal boundary conditions related to equivalent inlets are discussed. Procedures are described for the simulation of manhole cover loss, basement flooding, the representation of street geometry, and the distribution of runoff hydrographs between surface and underground networks. All these procedures are built into the simulation model. Relevant issues are illustrated on a set of examples, focusing on specific parameters and comparison with field measurements of flooding of the Motilal ki Chal catchment (Indore, India). Satisfactory agreement of observed and simulated hydrographs and maximum surface flooding levels is obtained. It is concluded that the presented approach is an improvement compared to the standard "virtual reservoir" approach commonly applied in most of the models.

  7. ClimoBase: Rouse Canadian Surface Observations of Weather, Climate, and Hydrological Variables, 1984-1998

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — ClimoBase is a collection of surface climate measurements collected in Northern Canada by Dr. Wayne Rouse between 1984 and 1998 in three locations: Churchill,...

  8. A comparison of native GPU computing versus OpenACC for implementing flow-routing algorithms in hydrological applications

    Science.gov (United States)

    Rueda, Antonio J.; Noguera, José M.; Luque, Adrián

    2016-02-01

    In recent years GPU computing has gained wide acceptance as a simple low-cost solution for speeding up computationally expensive processing in many scientific and engineering applications. However, in most cases accelerating a traditional CPU implementation for a GPU is a non-trivial task that requires a thorough refactorization of the code and specific optimizations that depend on the architecture of the device. OpenACC is a promising technology that aims at reducing the effort required to accelerate C/C++/Fortran code on an attached multicore device. Virtually with this technology the CPU code only has to be augmented with a few compiler directives to identify the areas to be accelerated and the way in which data has to be moved between the CPU and GPU. Its potential benefits are multiple: better code readability, less development time, lower risk of errors and less dependency on the underlying architecture and future evolution of the GPU technology. Our aim with this work is to evaluate the pros and cons of using OpenACC against native GPU implementations in computationally expensive hydrological applications, using the classic D8 algorithm of O'Callaghan and Mark for river network extraction as case-study. We implemented the flow accumulation step of this algorithm in CPU, using OpenACC and two different CUDA versions, comparing the length and complexity of the code and its performance with different datasets. We advance that although OpenACC can not match the performance of a CUDA optimized implementation (×3.5 slower in average), it provides a significant performance improvement against a CPU implementation (×2-6) with by far a simpler code and less implementation effort.

  9. Eco-hydrology: Groundwater flow and site factors in plant ecology

    Science.gov (United States)

    Klijn, Frans; Witte, Jan-Philip M.

    Résumé En écologie végétale, le site est un concept central. Un site, c'est l'endroit où une espèce végétale ou une communauté de plantes se développe le site assure un ensemble de conditions dans lesquelles elles vivent. Dans un matériau homogène à l'origine, l'écoulement gravitaire d'une nappe influence les conditions du site par l'intermédiaire de la distribution spatiale des nutriments et d'autres composés chimiques associés. Les remontées d'eau peuvent tout spécialement produire et maintenir les conditions du site essentielles pour différentes espèces et communautés de plantes relativement rares. Les écologues ont porté une attention accrue à ces remontées d'eau, en sorte qu'une coopération avec les hydrologues en a résulté, avec l'émergence d'une discipline propre, l'éco-hydrologie, à la limite des deux domaines scientifiques et liée au concept de site. Aux Pays-Bas, une classification des types d'eau, basée sur l'histoire de l'eau souterraine à proximité de la surface, a été mise en oeuvre pour constituer une base nationale de données géographiques sur les remontées d'eau d'intérêt écologique. Des analyses des correspondances des données de cette base, portant sur l'existence de certaines espèces de plantes, montrent que dans les sols sableux pauvres du Pléistocène la remontée d'eau explique très bien la présence de certaines espèces et communautés, alors que, dans les plaines fluviales et les régions de polders à sols argileux riches, l'influence de la remontée d'eau est masquée par l'importance des caractéristiques des sols. En conclusion donc, certaines espèces de plantes peuvent être utilisées comme des indicateurs de la remontée d'eau dans des diagnostiques et des levés de terrain rapides, mais à condition de prendre en permanence des précautions sur les limites de l'approche. Resumen En ecología botánica un concepto de gran importancia es el de emplazamiento, definido como el lugar que

  10. Effect of Energetic Plasma Flux on Flowing Liquid Lithium Surfaces

    Science.gov (United States)

    Kalathiparambil, Kishor; Jung, Soonwook; Christenson, Michael; Fiflis, Peter; Xu, Wenyu; Szott, Mathew; Ruzic, David

    2014-10-01

    An operational liquid lithium system with steady state flow driven by thermo-electric magneto-hydrodynamic force and capable of constantly refreshing the plasma exposed surface have been demonstrated at U of I. To evaluate the system performance in reactor relevant conditions, specifically to understand the effect of disruptive plasma events on the performance of the liquid metal PFCs, the setup was integrated to a pulsed plasma generator. A coaxial plasma generator drives the plasma towards a theta pinch which preferentially heats the ions, simulating ELM like flux, and the plasma is further guided towards the target chamber which houses the flowing lithium system. The effect of the incident flux is examined using diagnostic tools including triple Langmuir probe, calorimeter, rogowski coils, Ion energy analyzers, and fast frame spectral image acquisition with specific optical filters. The plasma have been well characterized and a density of ~1021 m-3, with electron temperature ~10 - 20 eV is measured, and final plasma velocities of 34 - 74 kms-1 have been observed. Calorimetric measurements using planar molybdenum targets indicate a maximum plasma energy (with 6 kV plasma gun and 20 kV theta pinch) of 0.08 MJm-2 with plasma divergence effects resulting in marginal reduction of 40 +/- 23 J in plasma energy. Further results from the other diagnostic tools, using the flowing lithium targets and the planar targets coated with lithium will be presented. DOE DE-SC0008587.

  11. Predictive model for convective flows induced by surface reactivity contrast

    Science.gov (United States)

    Davidson, Scott M.; Lammertink, Rob G. H.; Mani, Ali

    2018-05-01

    Concentration gradients in a fluid adjacent to a reactive surface due to contrast in surface reactivity generate convective flows. These flows result from contributions by electro- and diffusio-osmotic phenomena. In this study, we have analyzed reactive patterns that release and consume protons, analogous to bimetallic catalytic conversion of peroxide. Similar systems have typically been studied using either scaling analysis to predict trends or costly numerical simulation. Here, we present a simple analytical model, bridging the gap in quantitative understanding between scaling relations and simulations, to predict the induced potentials and consequent velocities in such systems without the use of any fitting parameters. Our model is tested against direct numerical solutions to the coupled Poisson, Nernst-Planck, and Stokes equations. Predicted slip velocities from the model and simulations agree to within a factor of ≈2 over a multiple order-of-magnitude change in the input parameters. Our analysis can be used to predict enhancement of mass transport and the resulting impact on overall catalytic conversion, and is also applicable to predicting the speed of catalytic nanomotors.

  12. Continuous vs. pulsating flow boiling. Part 2: Statistical comparison using response surface methodology

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Elmegaard, Brian; Meyer, Knud Erik

    2016-01-01

    Response surface methodology is used to investigate an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The flow pulsations are introduced by a flow modulating expansion device and compared with the baseline continuous flow provided by a stepper...

  13. Analysis of the structural parameters that influence gas production from the Devonian shale. Annual progress report, 1979-1980. Volume II. Data repository and reports published during fiscal year 1979-1980: regional structure, surface structure, surface fractures, hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Negus-De Wys, J.; Dixon, J. M.; Evans, M. A.; Lee, K. D.; Ruotsala, J. E.; Wilson, T. H.; Williams, R. T.

    1980-10-01

    This volume comprises appendices giving regional structure data, surface structure data, surface fracture data, and hydrology data. The fracture data covers oriented Devonian shale cores from West Virginia, Ohio, Virginia, Pennsylvania, and Kentucky. The subsurface structure of the Eastern Kentucky gas field is also covered. (DLC)

  14. On the appropriate definition of soil profile configuration and initial conditions for land surface-hydrology models in cold regions

    Science.gov (United States)

    Sapriza-Azuri, Gonzalo; Gamazo, Pablo; Razavi, Saman; Wheater, Howard S.

    2018-06-01

    Arctic and subarctic regions are amongst the most susceptible regions on Earth to global warming and climate change. Understanding and predicting the impact of climate change in these regions require a proper process representation of the interactions between climate, carbon cycle, and hydrology in Earth system models. This study focuses on land surface models (LSMs) that represent the lower boundary condition of general circulation models (GCMs) and regional climate models (RCMs), which simulate climate change evolution at the global and regional scales, respectively. LSMs typically utilize a standard soil configuration with a depth of no more than 4 m, whereas for cold, permafrost regions, field experiments show that attention to deep soil profiles is needed to understand and close the water and energy balances, which are tightly coupled through the phase change. To address this gap, we design and run a series of model experiments with a one-dimensional LSM, called CLASS (Canadian Land Surface Scheme), as embedded in the MESH (Modélisation Environmentale Communautaire - Surface and Hydrology) modelling system, to (1) characterize the effect of soil profile depth under different climate conditions and in the presence of parameter uncertainty; (2) assess the effect of including or excluding the geothermal flux in the LSM at the bottom of the soil column; and (3) develop a methodology for temperature profile initialization in permafrost regions, where the system has an extended memory, by the use of paleo-records and bootstrapping. Our study area is in Norman Wells, Northwest Territories of Canada, where measurements of soil temperature profiles and historical reconstructed climate data are available. Our results demonstrate a dominant role for parameter uncertainty, that is often neglected in LSMs. Considering such high sensitivity to parameter values and dependency on the climate condition, we show that a minimum depth of 20 m is essential to adequately represent

  15. Network analysis applications in hydrology

    Science.gov (United States)

    Price, Katie

    2017-04-01

    Applied network theory has seen pronounced expansion in recent years, in fields such as epidemiology, computer science, and sociology. Concurrent development of analytical methods and frameworks has increased possibilities and tools available to researchers seeking to apply network theory to a variety of problems. While water and nutrient fluxes through stream systems clearly demonstrate a directional network structure, the hydrological applications of network theory remain under­explored. This presentation covers a review of network applications in hydrology, followed by an overview of promising network analytical tools that potentially offer new insights into conceptual modeling of hydrologic systems, identifying behavioral transition zones in stream networks and thresholds of dynamical system response. Network applications were tested along an urbanization gradient in Atlanta, Georgia, USA. Peachtree Creek and Proctor Creek. Peachtree Creek contains a nest of five long­term USGS streamflow and water quality gages, allowing network application of long­term flow statistics. The watershed spans a range of suburban and heavily urbanized conditions. Summary flow statistics and water quality metrics were analyzed using a suite of network analysis techniques, to test the conceptual modeling and predictive potential of the methodologies. Storm events and low flow dynamics during Summer 2016 were analyzed using multiple network approaches, with an emphasis on tomogravity methods. Results indicate that network theory approaches offer novel perspectives for understanding long­ term and event­based hydrological data. Key future directions for network applications include 1) optimizing data collection, 2) identifying "hotspots" of contaminant and overland flow influx to stream systems, 3) defining process domains, and 4) analyzing dynamic connectivity of various system components, including groundwater­surface water interactions.

  16. Quantifying groundwater dependency of riparian surface hydrologic features using the exit gradient

    Science.gov (United States)

    This study examines groundwater exit gradients as a way to quantify groundwater interactions with surface water. We calibrated high resolution groundwater models for the basin fill sediments in the lower Calapooia watershed, Oregon, using data collected between 1928--2000. The e...

  17. Modelling of a free-surface ferrofluid flow

    Energy Technology Data Exchange (ETDEWEB)

    Habera, M., E-mail: habera@karlin.mff.cuni.cz; Hron, J., E-mail: hron@karlin.mff.cuni.cz

    2017-06-01

    The Cauchy's stress tensor of a ferrofluid exposed to an external magnetic field is subject to additional magnetic terms. For a linearly magnetizable medium, the terms result in interfacial magnetic force acting on the ferrofluid boundaries. This force changes the characteristics of many free-surface ferrofluid phenomena. The aim of this work is to implement this force into the incompressible Navier-Stokes equations and propose a numerical method to solve them. The interface of ferrofluid is tracked with the use of the characteristic level-set method and additional reinitialization step assures conservation of its volume. Incompressible Navier-Stokes equations are formulated for a divergence-free velocity fields while discrete interfacial forces are treated with continuous surface force model. Velocity-pressure coupling is implemented via the projection method. To predict the magnetic force effect quantitatively, Maxwell's equations for magnetostatics are solved in each time step. Finite element method is utilized for the spatial discretization. At the end of the work, equilibrium droplet shape are compared to known experimental results. - Highlights: • Incompressible Navier-Stokes equations are formulated for the problem of free-surface ferrofluid flow. • Computed equilibrium ferrofluid droplet shape is compared to known experimental result. • Magnetic field substantially changes the dynamics of ferrofluid dripping process.

  18. Frost Growth and Densification in Laminar Flow Over Flat Surfaces

    Science.gov (United States)

    Kandula, Max

    2011-01-01

    One-dimensional frost growth and densification in laminar flow over flat surfaces has been theoretically investigated. Improved representations of frost density and effective thermal conductivity applicable to a wide range of frost circumstances have been incorporated. The validity of the proposed model considering heat and mass diffusion in the frost layer is tested by a comparison of the predictions with data from various investigators for frost parameters including frost thickness, frost surface temperature, frost density and heat flux. The test conditions cover a range of wall temperature, air humidity ratio, air velocity, and air temperature, and the effect of these variables on the frost parameters has been exemplified. Satisfactory agreement is achieved between the model predictions and the various test data considered. The prevailing uncertainties concerning the role air velocity and air temperature on frost development have been elucidated. It is concluded that that for flat surfaces increases in air velocity have no appreciable effect on frost thickness but contribute to significant frost densification, while increase in air temperatures results in a slight increase the frost thickness and appreciable frost densification.

  19. Safety case for the disposal of spent nuclear fuel at Olkiluoto. Surface and near-surface hydrological modelling in the biosphere assessment BSA-2012

    International Nuclear Information System (INIS)

    Karvonen, T.

    2013-05-01

    The Finnish nuclear waste disposal company, Posiva Oy, is planning an underground repository for spent nuclear fuel to be constructed on the island of Olkiluoto on the south-west coast of Finland. This study is part of the biosphere assessment (BSA-2012) within the safety case for the repository. The surface hydrological modelling described in this report is aimed at providing link between radionuclide transport in the geosphere and in the biosphere systems. The SVAT-model and Olkiluoto site scale surface hydrological model were calibrated and validated in the present day conditions using the input data provided by the Olkiluoto Monitoring Programme (OMO). During the next 10 000 years the terrain and ecosystem development is to a large extent driven by the postglacial crustal uplift. UNTAMO is a GIS toolbox developed for simulating land-uplift driven or other changes in the biosphere. All the spatial and temporal input data (excluding meteorological data) needed in the surface hydrological modelling were provided by the UNTAMO toolbox. The specific outputs given by UNTAMO toolbox are time-dependent evolution of the biosphere objects. They are continuous and sufficiently homogeneous sub-areas of the modelled area that could potentially receive radionuclides released from the repository. Possible ecosystem types for biosphere objects are coast, lake, river, forest, cropland, pasture and wetland. The primary goal of this study was to compute vertical and horizontal water fluxes in the biosphere objects. These data will be used in the biosphere radionuclide transport calculations. The method adopted here is based on calculating average vertical and horizontal fluxes for biosphere objects from the results of the full 3D-model. It was not necessary to develop any simplified hydrological model for the biosphere objects. This report includes modelling results from for the Reference Case (present day climate) and Terr M axAgri Case (maximum extent of agricultural areas and

  20. Hydrological Process Simulation of Inland River Watershed: A Case Study of the Heihe River Basin with Multiple Hydrological Models

    Directory of Open Access Journals (Sweden)

    Lili Wang

    2018-04-01

    Full Text Available Simulating the hydrological processes of an inland river basin can help provide the scientific guidance to the policies of water allocation among different subbasins and water resource management groups within the subbasins. However, it is difficult to simulate the hydrological processes of an inland river basin with hydrological models due to the non-consistent hydrological characteristics of the entire basin. This study presents a solution to this problem with a case study about the hydrological process simulation in an inland river basin in China, Heihe River basin. It is divided into the upper, middle, and lower reaches based on the distinctive hydrological characteristics in the Heihe River basin, and three hydrological models are selected, applied, and tested to simulate the hydrological cycling processes for each reach. The upper reach is the contributing area with the complex runoff generation processes, therefore, the hydrological informatic modeling system (HIMS is utilized due to its combined runoff generation mechanisms. The middle reach has strong impacts of intensive human activities on the interactions of surface and subsurface flows, so a conceptual water balance model is applied to simulate the water balance process. For the lower reach, as the dissipative area with groundwater dominating the hydrological process, a groundwater modeling system with the embedment of MODFLOW model is applied to simulate the groundwater dynamics. Statistical parameters and water balance analysis prove that the three models have excellent performances in simulating the hydrological process of the three reaches. Therefore, it is an effective way to simulate the hydrological process of inland river basin with multiple hydrological models according to the characteristics of each subbasin.

  1. Hydrological influences on long-term gas flow trends at locations in the Vogtland/NW Bohemian seismic region (German-Czech border

    Directory of Open Access Journals (Sweden)

    J. Heinicke

    2007-06-01

    Full Text Available One of the typical methods for the identification of seismo-hydrological effects is to monitor changes in the free gas flow throughout springs or mofettes. For several years, the gas flow regime of mineral springs at Bad Brambach (Germany and mofettes in the Nature Park Soos (Czech Republic and its dependence on hydro-/meteorological parameters have been studied. The mineral spring ‘Wettinquelle’, Bad Brambach, is a well-known seismo- hydrologically sensitive location for swarmquakes at a special epicentral area of NW Bohemia. Since 2000, a slight upward trend in the gas flow of three Bad Brambach mineral springs has been observed, which became stronger after the ‘Eisenquelle’ spring capture reconstruction (winter 2003/2004. Similar behaviour could be detected at a mofette in Soos. The results correspond to a 3He/4He mantle ratio increase in gases at mofettes in the Cheb Basin (CZ traced by other authors for more than 12 years, and could give hints for a higher degassing activity of the magma body below that area. Common and special properties in the degassing regimes of the Bad Brambach and Soos locations are discussed. It is demonstrated that the long-term gas flow trend was interrupted in 2003 because of very low groundwater levels. This effect was amplified by the artificial groundwater lowering during the ‘Eisenquelle’ spring capture reconstruction.

  2. Concentration and spectroscopic characteristics of DOM in surface runoff and fracture flow in a cropland plot of a loamy soil.

    Science.gov (United States)

    Xian, Qingsong; Li, Penghui; Liu, Chen; Cui, Junfang; Guan, Zhuo; Tang, Xiangyu

    2018-05-01

    Being crucial for predicting the impact of source inputs on a watershed in rainfall events, an understanding of the dynamics and characteristics of dissolved organic matter (DOM) export from the soil under particular land use types, particularly those associated with underground flows is still largely lacking. A field study was carried out using a 1500m 2 slope farmland plot in the hilly area of Sichuan Basin, Southwest China. The discharge of surface runoff and fracture flow was recorded and samples were collected in four representative rainfall events. For DOM characterization, concentration of dissolved organic carbon (DOC) and absorbance/excitation-emission matrix (EEM) fluorescence were analyzed. Soil water potential was also determined using tensiometers for understanding the runoff generation mechanisms. The DOC values for both surface and fracture flow showed significant responses to rainfall, with hydrological path being the primary factor in determining DOM dynamics. EEM-PARAFAC analyses indicated that the soil DOM mainly consisted of two terrestrial humic-like components with peaks located at Ex/Em 270(380)/480nm (C1) and 250(320)/410nm (C2), respectively. Concentrations of these components also responded strongly to rainfall, fluctuating in good agreement with the corresponding DOCs. Although there was no change in the presence of the components themselves, their relative distributions varied during precipitation, with the C1/C2 ratio increasing with the proportion of soil pre-event water. As the dynamic changes of soil DOM characteristics can be successfully captured using spectroscopic techniques, they may serve as a tracer for understanding hydrological paths based on their potential correlations with water source differences during rains. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Efficiency assessment of runoff harvesting techniques using a 3D coupled surface-subsurface hydrological model

    International Nuclear Information System (INIS)

    Verbist, K.; Cronelis, W. M.; McLaren, R.; Gabriels, D.; Soto, G.

    2009-01-01

    In arid and semi-arid zones runoff harvesting techniques are often applied to increase the water retention and infiltration on steep slopes. Additionally, they act as an erosion control measure to reduce land degradation hazards. Both in literature and in the field, a large variety of runoff collecting systems are found, as well as large variations in design and dimensions. Therefore, detailed measurements were performed on a semi-arid slope in central Chile to allow identification of the effect of a simple water harvesting technique on soil water availability. For this purpose, twenty two TDR-probes were installed and were monitored continuously during and after a simulated rainfall event. These data were used to calibrate the 3D distributed flow model HydroGeoSphere, to assess the runoff components and soil water retention as influenced by the water harvesting technique, both under simulated and natural rainfall conditions. (Author) 6 refs.

  4. Seasonal dynamics of surface chlorophyll concentration and sea surface temperature, as indicator of hydrological structure of the ocean (by satellite data)

    Science.gov (United States)

    Shevyrnogov, Anatoly; Vysotskaya, Galina

    Continuous monitoring of phytopigment concentrations and sea surface temperature in the ocean by space-borne methods makes possible to estimate ecological condition of biocenoses in critical areas. Unlike land vegetation, hydrological processes largely determine phytoplank-ton dynamics, which may be either recurrent or random. The types of chlorophyll concentration dynamics and sea surface temperature can manifest as zones quasistationary by seasonal dynamics, quasistationary areas (QSA). In the papers of the authors (A. Shevyrnogov, G. Vysotskaya, E. Shevyrnogov, A study of the stationary and the anomalous in the ocean surface chlorophyll distribution by satellite data. International Journal of Remote Sensing, Vol. 25, No.7-8, pp. 1383-1387, April 2004 & A. P. Shevyrnogov, G. S. Vysotskaya, J. I. Gitelson, Quasistationary areas of chlorophyll concentra-tion in the world ocean as observed satellite data Advances in Space Research, Volume 18, Issue 7, Pages 129-132, 1996) existence of zones, which are quasi-stationary with similar seasonal dynamics of chlorophyll concentration at surface layer of ocean, was shown. Results were obtained on the base of processing of time series of satellite images SeaWiFS. It was shown that fronts and frontal zones coincide with dividing lines between quasi-stationary are-as, especially in areas of large oceanic streams. To study the dynamics of the ocean for the period from 1985 through 2012 we used data on the temperature of the surface layer of the ocean and chlorophyll concentration (AVHRR, SeaWiFS and MODIS). Biota of surface oceanic layer is more stable in comparison with quickly changing surface tem-perature. It gives a possibility to circumvent influence of high-frequency component (for exam-ple, a diurnal cycle) in investigation of dynamics of spatial distribution of surface streams. In addition, an analyses of nonstable ocean productivity phenomena, stood out time series of satellite images, showed existence of areas with

  5. Hydrology and Water Quality of the Rio Chama River, Northern New Mexico: Establishing a Base Line to Manage Flows

    Science.gov (United States)

    Salvato, L.; Crossey, L. J.

    2013-12-01

    The Rio Chama is the largest stream tributary to the Rio Grande in northern New Mexico. The river's geographic location in a semiarid region results in high rates of evapotranspiration and highly variable streamflow. The Rio Chama is part of the San Juan-Chama Drinking Water Project, in which water from the San Juan River, southern Colorado, is diverted across the continental divide to the Rio Chama. Surface water moves through Abiquiu, El Vado and Heron Reservoirs to the Rio Grande to supply Albuquerque with potable drinking water. The results of these anthropogenic influences are a modified flow regime, less variability, greater base-flows, and smaller peak flows. We examined selected locations throughout the Rio Chama system to provide base-line water quality data for ongoing studies. This information will contribute to the development of the best plan to optimize flow releases and maximize benefits of the stakeholders and especially the riparian and stream ecosystems. We report results of two sampling trips representing extremes of the hydrograph in summer 2012 and fall 2012. We collected field parameters, processed water samples, and analyzed them for major anions and cations. The geochemistry enables us to better understand the impact of monthly releases of San Juan river water. We captured two points of the river's streamflow range, 54 cubic feet per second in October 2012 and 1,000 cubic feet per second in August 2012 and looked for variability within the results. We found that the reservoirs exhibit varying anion concentrations from samples taken at different depths. We compared stream waters and selected well samples at a stream transect. These samples allowed us to compare shallow ground water with the stream, and they indicated that the changes in ground water are attributed to sulfate reduction. The anion and cation inputs were most likely derived from gypsum, calcite, and salts, as there are many creeks discharging into the Rio Chama whose drainage

  6. DNS of flows over superhydrophobic surfaces with small texture

    Science.gov (United States)

    Fairhall, Chris; Garcia-Mayoral, Ricardo

    2015-11-01

    We present results from direct numerical simulations of turbulent flows over superhydrophobic surfaces with small texture sizes, comparable to those of practical application. Textures studied with DNS are usually much larger, as the cost of the simulations would otherwise be prohibitive. For this reason, a multi-block code that allows for finer resolution near the walls has been developed. We focus particularly on the pressure distribution at the wall. This distribution can cause the deformation of the gas pockets, which can ultimately lead to their loss and that of the drag reduction effect. The layout of the texture causes stagnation pressures which can contribute substantially to the wall pressure signal (Seo et al. JFM, under review). We study a range of different textures and their influence on these pressures.

  7. Forest hydrology

    Science.gov (United States)

    Ge Sun; Devendra Amatya; Steve McNulty

    2016-01-01

    Forest hydrology studies the distribution, storage, movement, and quality of water and the hydrological processes in forest-dominated ecosystems. Forest hydrological science is regarded as the foundation of modern integrated water¬shed management. This chapter provides an overview of the history of forest hydrology and basic principles of this unique branch of...

  8. Surface area changes of Himalayan ponds as a proxy of hydrological climate-driven fluctuations

    Science.gov (United States)

    Salerno, Franco; Thakuri, Sudeep; Guyennon, Nicolas; Viviano, Gaetano; Tartari, Gianni

    2016-04-01

    The meteorological measurements at high-elevations of the Himalayan range are scarce due to the harsh conditions of these environments which limit the suitable maintenance of weather stations. As a consequence, the meager knowledge on how the climate is changed in the last decades at Himalayan high-elevations sets a serious limit upon the interpretation of relationships between causes and recent observed effects on the cryosphere. Although the glaciers masses reduction in Himalaya is currently sufficiently well described, how changes in climate drivers (precipitation and temperature) have influenced the melting and shrinkage processes are less clear. Consequently, the uncertainty related to the recent past amplifies when future forecasts are done, both for climate and impacts. In this context, a substantial body of research has already demonstrated the high sensitivity of lakes and ponds to climate. Some climate-related signals are highly visible and easily measurable in lakes. For example, climate-driven fluctuations in lake surface area have been observed in many remote sites. On interior Tibetan Plateau the lake growth since the late 1990s is mainly attributed to increased regional precipitation and weakened evaporation. Differently, other authors attribute at the observed increases of lake surfaces at the enhanced glacier melting. In our opinion these divergences found in literature are due to the type of glacial lakes considered in the study and in particular their relationship with glaciers. In general, in Himalaya three types of glacial lakes can be distinguished: (i) lakes that are not directly connected with glaciers, but that may have a glacier located in their basin (unconnected glacial lakes); (ii) supraglacial lakes, which develop on the surface of the glacier downstream; or (iii) proglacial lakes, which are moraine-dammed lakes that are in contact with the glacier front. Some of these lakes store large quantities of water and are susceptible to GLOFs

  9. Near-field flow structures about subcritical surface roughness

    Science.gov (United States)

    Doolittle, Charles J.; Drews, Scott D.; Goldstein, David B.

    2014-12-01

    Laminar flow over a periodic array of cylindrical surface roughness elements is simulated with an immersed boundary spectral method both to validate the method for subsequent studies and to examine how persistent streamwise vortices are introduced by a low Reynolds number roughness element. Direct comparisons are made with prior studies at a roughness-based Reynolds number Rek (=U(k) k/ν) of 205 and a diameter to spanwise spacing ratio d/λ of 1/3. Downstream velocity contours match present and past experiments very well. The shear layer developed over the top of the roughness element produces the downstream velocity deficit. Upstream of the roughness element, the vortex topology is found to be consistent with juncture flow experiments, creating three cores along the recirculation line. Streamtraces stemming from these upstream cores, however, have unexpectedly little effect on the downstream flowfield as lateral divergence of the boundary layer quickly dissipates their vorticity. Long physical relaxation time of the recirculating wake behind the roughness remains a prominent issue for simulating this type of flowfield.

  10. Gridded Surface Subsurface Hydrologic Analysis Modeling for Analysis of Flood Design Features at the Picayune Strand Restoration Project

    Science.gov (United States)

    2016-08-01

    restore its predrainage hydrology and ecological function for beneficial effects on flora and fauna in the project area and surrounding public lands. The...partnership with South Florida Water Management District (SFWMD), is constructing these features. Engineering support is required for hydrologic and...simulation accuracy and related resource requirements. Spatial data products such as digital elevation models, surveyed channel cross sections, soil

  11. Landscape Evolution in South Texas Savannas: Impact of Woody Encroachment on Land-Surface Hydrology

    Science.gov (United States)

    Basant, S.; Wilcox, B. P.

    2017-12-01

    South Texas shrubland savannas have seen extensive woody encroachment over the last century. The ecosystem is largely spread over the coastal sediments typified by subtle elevation differences which are marked by bands of thick vegetation. Together, they form a dendritic pattern of vegetation which resembles a drainage network. We hypothesize that these vegetation shifts from grassland to woodlands began with the woody encroachment of drainage networks first. This was helped mainly by two factors, a) cattle grazing, b) the undulating feature of the landscape, c) periodic high intensity storms every few years resulting in large overland flows. We propose that the overland flows generated by these periodic storms provided a `subsidy' of extra water accounting for the differential rate of biomass production in lowlands. We also propose that with the continued woody encroachment, the extent of redistribution of water has changed in extent, and in scale triggering vegetation dynamics which are more controlled at patch scales. Soil moisture data was collected for over a year using neutron moisture meter for 40 points spread over a micro catchment. Plot scale runoff and interception data was sampled for the same catchment. USGS historical streamflow data from nearby creeks was used to confirm the periodic trend of runoff generation. Control exerted by microtopography of the site was accounted by using DEM at 1m resolution. Soil water storage was found to be consistently higher for uplands with open areas while lower for wooded patches but the upland sites also exhibited variability based on the slope and soil texture. Runoff generated also varied on shrub cover, slope and soil order, but higher for areas with previous records of grazing. Most runoff events were < 2mm except for 2 hurricane events in our records which generated more than 100mm of runoff. This points to the importance the role of rainfall intensity and the scale of runoff redistribution in providing

  12. Full 2D observation of water surface elevation from SWOT under different flow conditions

    Science.gov (United States)

    Domeneghetti, Alessio; Schumann, Guy; Rui, Wei; Durand, Michael; Pavelsky, Tamlin

    2016-04-01

    The upcoming Surface Water and Ocean Topography (SWOT) satellite mission is a joint project of NASA, Centre National d'Etudes Spatiales (CNES, France), the Canadian Space Agency, and the Space Agency of the UK that will provide a first global, high-resolution observation of ocean and terrestrial water surface heights. Characterized by an observation swath of 120 km and an orbit repeat interval of about 21 days, SWOT will provide unprecedented bi-dimensional observations of rivers wider than 50-100 m. Despite many research activities that have investigated potential uses of remotely sensed data from SWOT, potentials and limitations of the spatial observations provided by the satellite mission for flood modeling still remain poorly understood and investigated. In this study we present a first analysis of the spatial observation of water surface elevation that is expected from SWOT for a 140 km reach of the middle-lower portion of the Po River, in Northern Italy. The river stretch is characterized by a main channel varying from 200-500 m in width and a floodplain that can be as wide as 5 km and that is delimited by a system of major embankments. The reconstruction of the hydraulic behavior of the Po River is performed by means of a quasi-2d model built with detailed topographic and bathymetric information (LiDAR, 2 m resolution), while the simulation of the spatial observation sensed by SWOT is performed with a SWOT simulator that mimics the satellite sensor characteristics. Referring to water surface elevations associated with different flow conditions (maximum, minimum and average flow reproduced by means of the quasi-2d numerical model) this work provides a first characterization of the spatial observations provided by SWOT and highlights the strengths and limitations of the expected products. By referring to a real river reach the analysis provides a credible example of the type of spatial observations that will be available after launch of SWOT and offers a first

  13. A Prototype Flux-Plate Heat-Flow Sensor for Venus Surface Heat-Flow Determinations

    Science.gov (United States)

    Morgan, Paul; Reyes, Celso; Smrekar, Suzanne E.

    2005-01-01

    Venus is the most Earth-like planet in the Solar System in terms of size, and the densities of the two planets are almost identical when selfcompression of the two planets is taken into account. Venus is the closest planet to Earth, and the simplest interpretation of their similar densities is that their bulk compositions are almost identical. Models of the thermal evolution of Venus predict interior temperatures very similar to those indicated for the regions of Earth subject to solid-state convection, but even global analyses of the coarse Pioneer Venus elevation data suggest Venus does not lose heat by the same primary heat loss mechanism as Earth, i.e., seafloor spreading. The comparative paucity of impact craters on Venus has been interpreted as evidence for relatively recent resurfacing of the planet associated with widespread volcanic and tectonic activity. The difference in the gross tectonic styles of Venus and Earth, and the origins of some of the enigmatic volcano-tectonic features on Venus, such as the coronae, appear to be intrinsically related to Venus heat loss mechanism(s). An important parameter in understanding Venus geological evolution, therefore, is its present surface heat flow. Before the complications of survival in the hostile Venus surface environment were tackled, a prototype fluxplate heat-flow sensor was built and tested for use under synthetic stable terrestrial surface conditions. The design parameters for this prototype were that it should operate on a conforming (sand) surface, with a small, self-contained power and recording system, capable of operating without servicing for at least several days. The precision and accuracy of the system should be < 5 mW/sq m. Additional information is included in the original extended abstract.

  14. Analysis of uncertainties, associated to the calculating hypothesis, in discharge tables for high flows estimating, based on mathematics models for calculating water surface profiles fore steady gradually varied flow; Analisis de las incertidumbres, asociadas a las hipotesis de calculo, en la estimacion de curvas de gasto para crcidas, basada en el empleo de modelo matematico de calculo hidraulico en regimen permanente

    Energy Technology Data Exchange (ETDEWEB)

    Aldana Valverde, A. L.; Gonzalez Rodriguez, J. C.

    1999-08-01

    In this paper are analyzed some of the most important factors which can influence on the results of calculating water surface profiles for steady gradually varied flow. In this case, the objective of this kind of modeling, has been the estimation of discharges tables for high flows of river station gages connected to the hydrologic automatic information system (SAIH) of the Confederacion Hidrografica del Sur de Espana, system named red Hidrosur. (Author) 3 refs

  15. Modelling hydrological changes in surface in relation with anthropogenic drivers and consequences on human health and local economic

    Science.gov (United States)

    Sandoz, Alain; Leblond, Agnès; Boutron, Olivier

    2016-04-01

    Marais des Baux are located between Alpilles in the North and the plain of the Crau (South-East) of the town of Arles, in the South of France. Already built in Roman times, swamps located at the outlet of the Baux valley basin have experienced an increased human pressure during last centuries. Apotheosis of human development is the period of post-war with Marshall Plan and the development of the Common Agricultural Policy (CAP). At the beginning of the 21st century, inverse hydrologic dynamic is observed. Renaturation of the lower parts of the marshes, where land is less profitable, has reversed the trend of previous centuries. To be sustainable, this annealing must be accompanied by water governance at the watershed scale. This work aims to help policy makers and managers to good governance of the territory. Hierarchical multi-scale approach has enabled a better understanding of hydrological flows. In addition, knowledge of different actors' strategies is not enough. There may be different interests and strategies within the same group of actors. In this case, this is what we observe between farmers located on the upstream parts of the watershed eager, for some, to increase irrigation, and those located downstream, in the marshes, forced pump to maintain water levels corresponding to the expectations of the majority of the actors. On the other hand, there is a negative image of still marsh near a rural population and new rural population. Decreasing pumping or to send a higher volume of water could significantly increase flooded areas. This increase in flooded areas could facilitate the development of certain mosquito species. These mosquitoes not only represent a potential health risk for human populations but also increase the discomfort felt by the local population and tourists. This discomfort may also have an impact on economic activity linked with tourism. The work allowed the testing of different scenarios of flooding, according to the hydraulic management

  16. Free-surface entrainment into a rimming flow containing surfactants

    Science.gov (United States)

    Thoroddsen, S. T.; Tan, Y.-K.

    2004-02-01

    We study experimentally the free-surface entrainment of tubes into a steady rimming flow formed inside a partially filled horizontally rotating cylinder. The liquid consists of a glycerin-water mixture containing surfactants (fatty acids). The phenomenon does not occur without the surfactants and the details are sensitive to their concentration. The entrainment of numerous closely spaced air tubes and/or surfactant columns can start intermittently along a two-dimensional stagnation line, but is usually associated with the appearance of an axially periodic vortex structure, the so-called shark teeth, which fixes the spanwise location of these tubes. The number of tubes is governed by the three-dimensional shape of the free surface, reducing from more than 10 to only two in each trough, as the rotation rate is increased. The tubes vary in diameter from 10-30 μm and can extend hundreds of diameters into the liquid layer before breaking up into a continuous stream of bubbles and/or drops. The tubes are driven through the stagnation line by the strong viscous shear and are stretched in the downstream direction. The entrainment starts when the Capillary number Ca=μωR/σ≃0.4.

  17. Free Surface Flows and Extensional Rheology of Polymer Solutions

    Science.gov (United States)

    Dinic, Jelena; Jimenez, Leidy Nallely; Biagioli, Madeleine; Estrada, Alexandro; Sharma, Vivek

    Free-surface flows - jetting, spraying, atomization during fuel injection, roller-coating, gravure printing, several microfluidic drop/particle formation techniques, and screen-printing - all involve the formation of axisymmetric fluid elements that spontaneously break into droplets by a surface-tension-driven instability. The growth of the capillary-driven instability and pinch-off dynamics are dictated by a complex interplay of inertial, viscous and capillary stresses for simple fluids. Additional contributions by elasticity, extensibility and extensional viscosity play a role for complex fluids. We show that visualization and analysis of capillary-driven thinning and pinch-off dynamics of the columnar neck in an asymmetric liquid bridge created by dripping-onto-substrate (DoS) can be used for characterizing the extensional rheology of complex fluids. Using a wide variety of complex fluids, we show the measurement of the extensional relaxation time, extensional viscosity, power-law index and shear viscosity. Lastly, we elucidate how polymer composition, flexibility, and molecular weight determine the thinning and pinch-off dynamics of polymeric complex fluids.

  18. Using subdivision surfaces and adaptive surface simplification algorithms for modeling chemical heterogeneities in geophysical flows

    Science.gov (United States)

    Schmalzl, JöRg; Loddoch, Alexander

    2003-09-01

    We present a new method for investigating the transport of an active chemical component in a convective flow. We apply a three-dimensional front tracking method using a triangular mesh. For the refinement of the mesh we use subdivision surfaces which have been developed over the last decade primarily in the field of computer graphics. We present two different subdivision schemes and discuss their applicability to problems related to fluid dynamics. For adaptive refinement we propose a weight function based on the length of triangle edge and the sum of the angles of the triangle formed with neighboring triangles. In order to remove excess triangles we apply an adaptive surface simplification method based on quadric error metrics. We test these schemes by advecting a blob of passive material in a steady state flow in which the total volume is well preserved over a long time. Since for time-dependent flows the number of triangles may increase exponentially in time we propose the use of a subdivision scheme with diffusive properties in order to remove the small scale features of the chemical field. By doing so we are able to follow the evolution of a heavy chemical component in a vigorously convecting field. This calculation is aimed at the fate of a heavy layer at the Earth's core-mantle boundary. Since the viscosity variation with temperature is of key importance we also present a calculation with a strongly temperature-dependent viscosity.

  19. Hydrogeochemistry and isotope hydrology of surface water and groundwater systems in the Ellembelle district, Ghana, West Africa

    Science.gov (United States)

    Edjah, A. K. M.; Akiti, T. T.; Osae, S.; Adotey, D.; Glover, E. T.

    2017-05-01

    An integrated approach based on the hydrogeochemistry and the isotope hydrology of surface water and groundwater was carried out in the Ellembelle district of the Western Region of Ghana. Measurement of physical parameters (pH, temperature, salinity, total dissolved solutes, total hardness and conductivity), major ions (Ca2+, Mg2+, Na+, K+, HCO3 -, Cl-, SO4 2- and NO3 -), and stable isotopes (δ2H and δ18O) in 7 rivers, 13 hand-dug wells and 18 boreholes were taken. Na+ was the dominant cation and HCO3 - was the dominant anion for both rivers and groundwater. The dominant hydrochemical facies for the rivers were Na-K-HCO3 - type while that of the groundwater (hand-dug wells and boreholes) were Na-Cl and Na-HCO3 - type. According to the Gibbs diagram, majority of the rivers fall in the evaporation-crystallization field and majority of the hand-dug wells and the boreholes fall in the rock dominance field. From the stable isotope composition measurements, all the rivers appeared to be evaporated, 60 % of the hand-dug wells and 70 % of the boreholes clustered along and in between the global meteoric water line and the local meteoric water line, suggesting an integrative and rapid recharge from meteoric origin.

  20. The geographic distribution of strontium isotopes in Danish surface waters - A base for provenance studies in archaeology, hydrology and agriculture

    International Nuclear Information System (INIS)

    Frei, Karin M.; Frei, Robert

    2011-01-01

    Research highlights: → Strontium isotope data of 192 surface waters from Denmark. → Geographic baseline distribution of bio-available fractions. → Applicable for provenance studies within archaeology, geology, agriculture and hydrology. → Proposal of a band of strontium isotope values to characterize 'local' Danish signatures. - Abstract: In this paper Sr isotope signatures are reported for 192 surface water (lakes/ponds and rivers/creeks) samples from within Denmark and an isotope distribution map is presented that may serve as a base for provenance applications, including archaeological migration studies, ground water - surface water - seawater interaction/contamination monitoring, and potentially for agricultural applications, including cases of authenticity proof for particular food products. The Sr isotopic compositions of surface waters range from 87 Sr/ 86 Sr = 0.7078 to 0.7125 (average 0.7096 ± 0.0016; 2σ). This average value lies above the range of 87 Sr/ 86 Sr values between 0.7078 and 0.7082 expected from Late Cretaceous to Early Tertiary (Oligocene) limestones which form the dominant bedrock type in a NW-SE trending belt in Denmark. The elevated 87 Sr/ 86 Sr signatures >∼0.7095 are explained by additions to the surface waters of radiogenic Sr predominantly derived from the near-surface weathering and wash-out of Quarternary glaciogenic tills and soils deposited and formed during and after the last two ice age stages (Saale and Weichsel). The Sr isotopic compositions and concentrations of the surface waters can, therefore, best be modeled by a two-component mixing involving carbonaceous bedrock and glaciogenic cover sediments as the two predominant Sr sources. A feasibility study for using Sr isotopic compositions of surface waters as a proxy for bio-available Sr signatures was conducted in a representative test area on Zealand (Land of Legends, Lejre) where there is no use and application of commercial fertilizers. It is demonstrated that

  1. Hydrology team

    Science.gov (United States)

    Ragan, R.

    1982-01-01

    General problems faced by hydrologists when using historical records, real time data, statistical analysis, and system simulation in providing quantitative information on the temporal and spatial distribution of water are related to the limitations of these data. Major problem areas requiring multispectral imaging-based research to improve hydrology models involve: evapotranspiration rates and soil moisture dynamics for large areas; the three dimensional characteristics of bodies of water; flooding in wetlands; snow water equivalents; runoff and sediment yield from ungaged watersheds; storm rainfall; fluorescence and polarization of water and its contained substances; discriminating between sediment and chlorophyll in water; role of barrier island dynamics in coastal zone processes; the relationship between remotely measured surface roughness and hydraulic roughness of land surfaces and stream networks; and modeling the runoff process.

  2. Two-Dimensional Hydrodynamic Simulation of Surface-Water Flow and Transport to Florida Bay through the Southern Inland and Coastal Systems (SICS)

    Science.gov (United States)

    Swain, Eric D.; Wolfert, Melinda A.; Bales, Jerad D.; Goodwin, Carl R.

    2004-01-01

    Successful restoration of the southern Florida ecosystem requires extensive knowledge of the physical characteristics and hydrologic processes controlling water flow and transport of constituents through extremely low-gradient freshwater marshes, shallow mangrove-fringed coastal creeks and tidal embayments, and near-shore marine waters. A sound, physically based numerical model can provide simulations of the differing hydrologic conditions that might result from various ecosystem restoration scenarios. Because hydrology and ecology are closely linked in southern Florida, hydrologic model results also can be used by ecologists to evaluate the degree of ecosystem restoration that could be achieved for various hydrologic conditions. A robust proven model, SWIFT2D, (Surface-Water Integrated Flow and Transport in Two Dimensions), was modified to simulate Southern Inland and Coastal Systems (SICS) hydrodynamics and transport conditions. Modifications include improvements to evapotranspiration and rainfall calculation and to the algorithms that describe flow through coastal creeks. Techniques used in this model should be applicable to other similar low-gradient marsh settings in southern Florida and elsewhere. Numerous investigations were conducted within the SICS area of southeastern Everglades National Park and northeastern Florida Bay to provide data and parameter values for model development and testing. The U.S. Geological Survey and the National Park Service supported investigations for quantification of evapotranspiration, vegetative resistance to flow, wind-induced flow, land elevations, vegetation classifications, salinity conditions, exchange of ground and surface waters, and flow and transport in coastal creeks and embayments. The good agreement that was achieved between measured and simulated water levels, flows, and salinities through minimal adjustment of empirical coefficients indicates that hydrologic processes within the SICS area are represented properly

  3. Estimation of subsurface hydrological parameters around Akwuke, Enugu, Nigeria using surface resistivity measurements

    International Nuclear Information System (INIS)

    Utom, Ahamefula U; Odoh, Benard I; Egboka, Boniface C E; Egboka, Nkechi E; Okeke, Harold C

    2013-01-01

    As few boreholes may be available and carrying out pumping tests can be expensive and time consuming, relationships between aquifer characteristics and the electrical parameters of different geoelectric layers exist. Data from 19 vertical electrical soundings (VESs; 13 of these selected for evaluation) was recorded with a Schlumberger electrode configuration in the area around Akwuke, Enugu, Nigeria. The data was interpreted by computer iterative modelling with curve matching for calibration purposes. Geoelectric cross-sections along a number of lines were prepared to ascertain the overall distribution of the resistivity responses of the subsurface lithology. Identified probable shallow aquifer resistivity, thickness and depth values are in the range of 28–527 Ωm, 2.1–22.5 m and 3.1–28.3 m respectively. As our aquifer system consists of fine-grained, clay–silty sand materials, a modification of the Archie equations (Waxman–Smits model) was adopted to determine the true formation factor using the relationship between the apparent formation factor and the pore water resistivity. This representation of the effects of a separate conducting path due to the presence of clay particles in the aquifer materials was used in making reliable estimations of aquifer properties. The average hydraulic conductivity of 8.96 × 10 −4 m s −1 transmissivity ranging between 1.88 × 10 −3 and 2.02 × 10 −3 m 2 s −1 estimated from surface resistivity measurements correlated well with the available field data. Results of the study also showed a direct relationship between aquifer transmissivity and modified transverse resistance (R 2 = 0.85). (paper)

  4. Free surface profiles in river flows: Can standard energy-based gradually-varied flow computations be pursued?

    Science.gov (United States)

    Cantero, Francisco; Castro-Orgaz, Oscar; Garcia-Marín, Amanda; Ayuso, José Luis; Dey, Subhasish

    2015-10-01

    Is the energy equation for gradually-varied flow the best approximation for the free surface profile computations in river flows? Determination of flood inundation in rivers and natural waterways is based on the hydraulic computation of flow profiles. This is usually done using energy-based gradually-varied flow models, like HEC-RAS, that adopts a vertical division method for discharge prediction in compound channel sections. However, this discharge prediction method is not so accurate in the context of advancements over the last three decades. This paper firstly presents a study of the impact of discharge prediction on the gradually-varied flow computations by comparing thirteen different methods for compound channels, where both energy and momentum equations are applied. The discharge, velocity distribution coefficients, specific energy, momentum and flow profiles are determined. After the study of gradually-varied flow predictions, a new theory is developed to produce higher-order energy and momentum equations for rapidly-varied flow in compound channels. These generalized equations enable to describe the flow profiles with more generality than the gradually-varied flow computations. As an outcome, results of gradually-varied flow provide realistic conclusions for computations of flow in compound channels, showing that momentum-based models are in general more accurate; whereas the new theory developed for rapidly-varied flow opens a new research direction, so far not investigated in flows through compound channels.

  5. A prototype of radar-drone system for measuring the surface flow velocity at river sites and discharge estimation

    Science.gov (United States)

    Moramarco, Tommaso; Alimenti, Federico; Zucco, Graziano; Barbetta, Silvia; Tarpanelli, Angelica; Brocca, Luca; Mezzanotte, Paolo; Rosselli, Luca; Orecchini, Giulia; Virili, Marco; Valigi, Paolo; Ciarfuglia, Thomas; Pagnottelli, Stefano

    2015-04-01

    Discharge estimation at a river site depends on local hydraulic conditions identified by recording water levels. In fact, stage monitoring is straightforward and relatively inexpensive compared with the cost necessary to carry out flow velocity measurements which are, however, limited to low flows and constrained by the accessibility of the site. In this context the mean flow velocity is hard to estimate for high flow, affecting de-facto the reliability of discharge assessment for extreme events. On the other hand, the surface flow velocity can be easily monitored by using radar sensors allowing to achieve a good estimate of discharge by exploiting the entropy theory applied to rivers hydraulic (Chiu,1987). Recently, a growing interest towards the use of Unmanned Aerial Vehicle (UVA), henceforth drone, for topographic applications is observed and considering their capability drones may be of a considerable interest for the hydrological monitoring and in particular for streamflow measurements. With this aim, for the first time, a miniaturized Doppler radar sensor, operating at 24 GHz, will be mounted on a drone to measure the surface flow velocity in rivers. The sensor is constituted by a single-board circuit (i.e. is a fully planar circuits - no waveguides) with the antenna on one side and the front-end electronic on the other side (Alimenti et al., 2007). The antenna has a half-power beam width of less than 10 degrees in the elevation plane and a gain of 13 dBi. The radar is equipped with a monolithic oscillator and transmits a power of about 4 mW at 24 GHz. The sensor is mounted with an inclination of 45 degrees with respect to the drone flying plane and such an angle is considered in recovering the surface speed of the water. The drone is a quadricopter that has more than 30 min, flying time before recharging the battery. Furthermore its flying plan can be scheduled with a suitable software and is executed thanks to the on-board sensors (GPS, accelerometers

  6. Independent technical review and analysis of hydraulic modeling and hydrology under low-flow conditions of the Des Plaines River near Riverside, Illinois

    Science.gov (United States)

    Over, Thomas M.; Straub, Timothy D.; Hortness, Jon E.; Murphy, Elizabeth A.

    2012-01-01

    The U.S. Geological Survey (USGS) has operated a streamgage and published daily flows for the Des Plaines River at Riverside since Oct. 1, 1943. A HEC-RAS model has been developed to estimate the effect of the removal of Hofmann Dam near the gage on low-flow elevations in the reach approximately 3 miles upstream from the dam. The Village of Riverside, the Illinois Department of Natural Resources-Office of Water Resources (IDNR-OWR), and the U. S. Army Corps of Engineers-Chicago District (USACE-Chicago) are interested in verifying the performance of the HEC-RAS model for specific low-flow conditions, and obtaining an estimate of selected daily flow quantiles and other low-flow statistics for a selected period of record that best represents current hydrologic conditions. Because the USGS publishes streamflow records for the Des Plaines River system and provides unbiased analyses of flows and stream hydraulic characteristics, the USGS served as an Independent Technical Reviewer (ITR) for this study.

  7. Surface-water hydrology and quality, and macroinvertebrate and smallmouth bass populations in four stream basins in southwestern Wisconsin, 1987-90

    Science.gov (United States)

    Graczyk, David J.; Lillie, Richard A.; Schlesser, Roger A.; Mason, John W.; Lyons, John D.; Kerr, Roger A.; Graczyk, David J.

    1993-01-01

    Data on streamflow, water quality, and macroinvertebrate and smallmouth bass (microptercus dolomieni) populations were collected from July 1987 through September 1990, in four streams in southwestern Wisconsin to determine the effect of surface-water hydrology and quality on populations of macroinvertebrates and smallmouth bass. The study was a joint project of the U.S. Geological Survey and the Wisconsin Department of Natural Resources.

  8. Effects of confinement & surface roughness in electrorheological flows

    Science.gov (United States)

    Helal, Ahmed; Telleria, Maria J.; Wang, Julie; Strauss, Marc; Murphy, Mike; McKinley, Gareth; Hosoi, A. E.

    2014-11-01

    Electrorheological (ER) fluids are dielectric suspensions that exhibit a fast, reversible change in rheological properties with the application of an external electric field. Upon the application of the electric field, the material develops a field-dependent yield stress that is typically modeled using a Bingham plastic model. ER fluids are promising for designing small, cheap and rapidly actuated hydraulic devices such as rapidly-switchable valves, where fluid flowing in a microchannel can be arrested by applying an external electric field. In the lubrication limit, for a Bingham plastic fluid, the maximum pressure the channel can hold, before yielding, is a function of the field-dependent yield stress, the length of the channel and the electrode gap. In practice, the finite width of the channel and the surface roughness of the electrodes could affect the maximum yield pressure but a quantitative understanding of these effects is currently lacking. In this study, we experimentally investigate the effects of the channel aspect ratio (width/height) and the effects of electrode roughness on the performance of ER valves. Based on this quantitative analysis, we formulate new performance metrics for ER valves as well as design rules for ER valves that will help guide and optimize future designs.

  9. Using SWAT-MODFLOW to simulate groundwater flow and groundwater-surface water interactions in an intensively irrigated stream-aquifer system

    Science.gov (United States)

    Wei, X.; Bailey, R. T.

    2017-12-01

    Agricultural irrigated watersheds in semi-arid regions face challenges such as waterlogging, high soil salinity, reduced crop yield, and leaching of chemical species due to extreme shallow water tables resulting from long-term intensive irrigation. Hydrologic models can be used to evaluate the impact of land management practices on water yields and groundwater-surface water interactions in such regions. In this study, the newly developed SWAT-MODFLOW, a coupled surface/subsurface hydrologic model, is applied to a 950 km2 watershed in the Lower Arkansas River Valley (southeastern Colorado). The model accounts for the influence of canal diversions, irrigation applications, groundwater pumping, and earth canal seepage losses. The model provides a detailed description of surface and subsurface flow processes, thereby enabling detailed description of watershed processes such as runoff, infiltration, in-streamflow, three-dimensional groundwater flow in a heterogeneous aquifer system with sources and sinks (e.g. pumping, seepage to subsurface drains), and spatially-variable surface and groundwater exchange. The model was calibrated and tested against stream discharge from 5 stream gauges in the Arkansas River and its tributaries, groundwater levels from 70 observation wells, and evapotranspiration (ET) data estimated from satellite (ReSET) data during the 1999 to 2007 period. Since the water-use patterns within the study area are typical of many other irrigated river valleys in the United States and elsewhere, this modeling approach is transferable to other regions.

  10. Modeling sheet-flow sand transport under progressive surface waves

    NARCIS (Netherlands)

    Kranenburg, Wouter

    2013-01-01

    In the near-shore zone, energetic sea waves generate sheet-flow sand transport. In present day coastal models, wave-induced sheet-flow sand transport rates are usually predicted with semi-empirical transport formulas, based on extensive research on this phenomenon in oscillatory flow tunnels.

  11. Experimental calibration and validation of sewer/surface flow exchange equations in steady and unsteady flow conditions

    Science.gov (United States)

    Rubinato, Matteo; Martins, Ricardo; Kesserwani, Georges; Leandro, Jorge; Djordjević, Slobodan; Shucksmith, James

    2017-09-01

    The linkage between sewer pipe flow and floodplain flow is recognised to induce an important source of uncertainty within two-dimensional (2D) urban flood models. This uncertainty is often attributed to the use of empirical hydraulic formulae (the one-dimensional (1D) weir and orifice steady flow equations) to achieve data-connectivity at the linking interface, which require the determination of discharge coefficients. Because of the paucity of high resolution localised data for this type of flows, the current understanding and quantification of a suitable range for those discharge coefficients is somewhat lacking. To fulfil this gap, this work presents the results acquired from an instrumented physical model designed to study the interaction between a pipe network flow and a floodplain flow. The full range of sewer-to-surface and surface-to-sewer flow conditions at the exchange zone are experimentally analysed in both steady and unsteady flow regimes. Steady state measured discharges are first analysed considering the relationship between the energy heads from the sewer flow and the floodplain flow; these results show that existing weir and orifice formulae are valid for describing the flow exchange for the present physical model, and yield new calibrated discharge coefficients for each of the flow conditions. The measured exchange discharges are also integrated (as a source term) within a 2D numerical flood model (a finite volume solver to the 2D Shallow Water Equations (SWE)), which is shown to reproduce the observed coefficients. This calibrated numerical model is then used to simulate a series of unsteady flow tests reproduced within the experimental facility. Results show that the numerical model overestimated the values of mean surcharge flow rate. This suggests the occurrence of additional head losses in unsteady conditions which are not currently accounted for within flood models calibrated in steady flow conditions.

  12. Human effects on the hydrologic system of the Verde Valley, central Arizona, 1910–2005 and 2005–2110, using a regional groundwater flow model

    Science.gov (United States)

    Garner, Bradley D.; Pool, D.R.; Tillman, Fred D.; Forbes, Brandon T.

    2013-01-01

    Water budgets were developed for the Verde Valley of central Arizona in order to evaluate the degree to which human stresses have affected the hydrologic system and might affect it in the future. The Verde Valley is a portion of central Arizona wherein concerns have been raised about water availability, particularly perennial base flow of the Verde River. The Northern Arizona Regional Groundwater Flow Model (NARGFM) was used to generate the water budgets and was run in several configurations for the 1910–2005 and 2005–2110 time periods. The resultant water budgets were subtracted from one another in order to quantify the relative changes that were attributable solely to human stresses; human stresses included groundwater withdrawals and incidental and artificial recharge but did not include, for example, human effects on the global climate. Three hypothetical and varied conditions of human stresses were developed and applied to the model for the 2005–2110 period. On the basis of this analysis, human stresses during 1910–2005 were found to have already affected the hydrologic system of the Verde Valley, and human stresses will continue to affect the hydrologic system during 2005–2110. Riparian evapotranspiration decreased and underflow into the Verde Valley increased because of human stresses, and net groundwater discharge to the Verde River in the Verde Valley decreased for the 1910–2005 model runs. The model also showed that base flow at the upstream end of the study area, as of 2005, was about 4,900 acre-feet per year less than it would have been in the absence of human stresses. At the downstream end of the Verde Valley, base flow had been reduced by about 10,000 acre-feet per year by the year 2005 because of human stresses. For the 2005–2110 period, the model showed that base flow at the downstream end of the Verde Valley may decrease by an additional 5,400 to 8,600 acre-feet per year because of past, ongoing, and hypothetical future human

  13. A regional-scale, high resolution dynamical malaria model that accounts for population density, climate and surface hydrology.

    Science.gov (United States)

    Tompkins, Adrian M; Ermert, Volker

    2013-02-18

    The relative roles of climate variability and population related effects in malaria transmission could be better understood if regional-scale dynamical malaria models could account for these factors. A new dynamical community malaria model is introduced that accounts for the temperature and rainfall influences on the parasite and vector life cycles which are finely resolved in order to correctly represent the delay between the rains and the malaria season. The rainfall drives a simple but physically based representation of the surface hydrology. The model accounts for the population density in the calculation of daily biting rates. Model simulations of entomological inoculation rate and circumsporozoite protein rate compare well to data from field studies from a wide range of locations in West Africa that encompass both seasonal endemic and epidemic fringe areas. A focus on Bobo-Dioulasso shows the ability of the model to represent the differences in transmission rates between rural and peri-urban areas in addition to the seasonality of malaria. Fine spatial resolution regional integrations for Eastern Africa reproduce the malaria atlas project (MAP) spatial distribution of the parasite ratio, and integrations for West and Eastern Africa show that the model grossly reproduces the reduction in parasite ratio as a function of population density observed in a large number of field surveys, although it underestimates malaria prevalence at high densities probably due to the neglect of population migration. A new dynamical community malaria model is publicly available that accounts for climate and population density to simulate malaria transmission on a regional scale. The model structure facilitates future development to incorporate migration, immunity and interventions.

  14. Determination of averaged axisymmetric flow surfaces according to results obtained by numerical simulation of flow in turbomachinery

    Directory of Open Access Journals (Sweden)

    Bogdanović-Jovanović Jasmina B.

    2012-01-01

    Full Text Available In the increasing need for energy saving worldwide, the designing process of turbomachinery, as an essential part of thermal and hydroenergy systems, goes in the direction of enlarging efficiency. Therefore, the optimization of turbomachinery designing strongly affects the energy efficiency of the entire system. In the designing process of turbomachinery blade profiling, the model of axisymmetric fluid flows is commonly used in technical practice, even though this model suits only the profile cascades with infinite number of infinitely thin blades. The actual flow in turbomachinery profile cascades is not axisymmetric, and it can be fictively derived into the axisymmetric flow by averaging flow parameters in the blade passages according to the circular coordinate. Using numerical simulations of flow in turbomachinery runners, its operating parameters can be preliminarily determined. Furthermore, using the numerically obtained flow parameters in the blade passages, averaged axisymmetric flow surfaces in blade profile cascades can also be determined. The method of determination of averaged flow parameters and averaged meridian streamlines is presented in this paper, using the integral continuity equation for averaged flow parameters. With thus obtained results, every designer can be able to compare the obtained averaged flow surfaces with axisymmetric flow surfaces, as well as the specific work of elementary stages, which are used in the procedure of blade designing. Numerical simulations of flow in an exemplary axial flow pump, used as a part of the thermal power plant cooling system, were performed using Ansys CFX. [Projekat Ministarstva nauke Republike Srbije, br. TR33040: Revitalization of existing and designing new micro and mini hydropower plants (from 100 kW to 1000 kW in the territory of South and Southeast Serbia

  15. Hydrology Project

    International Nuclear Information System (INIS)

    Anon.

    Research carried out in the 'Hydrology Project' of the Centro de Energia Nuclear na Agricultura', Piracicaba, Sao Paulo State, Brazil, are described. Such research comprises: Amazon hydrology and Northeast hydrology. Techniques for the measurement of isotope ratios are used. (M.A.) [pt

  16. Upper Meter Processes: Short Wind Waves, Surface Flow, and Micro-Turbulence

    National Research Council Canada - National Science Library

    Jaehne, Bernd

    2000-01-01

    The primary goal of this project was to advance the knowledge of small-scale air-sea interaction processes at the ocean surface, focussing on the dynamics of short waves, the surface flow field and the micro-turbulence...

  17. Simulations of ecosystem hydrological processes using a unified multi-sca