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Showing 1 - 200 of 3175 Journals sorted alphabetically
A Practical Logic of Cognitive Systems     Full-text available via subscription   (Followers: 8)
AASRI Procedia     Open Access   (Followers: 14)
Academic Pediatrics     Hybrid Journal   (Followers: 28, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 22, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 90, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 25, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 33, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 5)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 6, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 376, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 27, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 2)
Acta de Investigación Psicológica     Open Access   (Followers: 3)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (Followers: 1, SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 235, SJR: 3.683, h-index: 202)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.615, h-index: 21)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.442, h-index: 21)
Acta Oecologica     Hybrid Journal   (Followers: 10, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 1)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 25, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 6)
Acute Pain     Full-text available via subscription   (Followers: 14)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 7)
Additive Manufacturing     Hybrid Journal   (Followers: 9, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Cement Based Materials     Full-text available via subscription   (Followers: 3)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 128, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 16, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 8, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 12, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 27, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 10, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 10, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 14, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 2, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 28, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 7, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 3)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 27, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 10, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 19, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.223, h-index: 22)
Advances in Dermatology     Full-text available via subscription   (Followers: 14)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 10)
Advances in Digestive Medicine     Open Access   (Followers: 8)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 21)
Advances in Ecological Research     Full-text available via subscription   (Followers: 42, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 27, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 6)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 42, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 1)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 7)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 54, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
Advances in Genetics     Full-text available via subscription   (Followers: 14, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 7)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 21, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.497, h-index: 31)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 1, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 36, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 14, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 21)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 3)
Advances in Oncobiology     Full-text available via subscription   (Followers: 1)
Advances in Organ Biology     Full-text available via subscription   (Followers: 1)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 6, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 5, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 10)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 7)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 59)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.1, h-index: 2)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 5)
Advances in Space Research     Full-text available via subscription   (Followers: 375, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 5)
Advances in Surgery     Full-text available via subscription   (Followers: 9, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 29, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 17)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 46, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 333, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 9, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 429, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 31, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 43, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 1)
Agriculture and Natural Resources     Open Access   (Followers: 2)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 56, SJR: 1.879, h-index: 120)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.434, h-index: 14)
Air Medical J.     Hybrid Journal   (Followers: 5, SJR: 0.234, h-index: 18)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.285, h-index: 3)
Alcohol     Hybrid Journal   (Followers: 11, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 9)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access   (Followers: 1)
Algal Research     Partially Free   (Followers: 9, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 5, SJR: 0.776, h-index: 35)
Alpha Omegan     Full-text available via subscription   (SJR: 0.121, h-index: 9)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 9, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 48, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 4)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 6)
American Heart J.     Hybrid Journal   (Followers: 50, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 50, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 42, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 10, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 14, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 31, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 26, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 32, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 42, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 189, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 62, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 6)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 27, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 27, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 37, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 6)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 61, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 14)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 4, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 39, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 165, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 10, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1)

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Journal Cover Advances in Water Resources
  [SJR: 2.408]   [H-I: 94]   [46 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0309-1708
   Published by Elsevier Homepage  [3175 journals]
  • Modelling coupled microbial processes in the subsurface: Model
           development, verification, evaluation and application
    • Authors: Shakil A. Masum; Hywel R. Thomas
      Pages: 1 - 17
      Abstract: Publication date: June 2018
      Source:Advances in Water Resources, Volume 116
      Author(s): Shakil A. Masum, Hywel R. Thomas
      To study subsurface microbial processes, a coupled model which has been developed within a Thermal-Hydraulic-Chemical-Mechanical (THCM) framework is presented. The work presented here, focuses on microbial transport, growth and decay mechanisms under the influence of multiphase flow and bio-geochemical reactions. In this paper, theoretical formulations and numerical implementations of the microbial model are presented. The model has been verified and also evaluated against relevant experimental results. Simulated results show that the microbial processes have been accurately implemented and their impacts on porous media properties can be predicted either qualitatively or quantitatively or both. The model has been applied to investigate biofilm growth in a sandstone core that is subjected to a two-phase flow and variable pH conditions. The results indicate that biofilm growth (if not limited by substrates) in a multiphase system largely depends on the hydraulic properties of the medium. When the change in porewater pH which occurred due to dissolution of carbon dioxide gas is considered, growth processes are affected. For the given parameter regime, it has been shown that the net biofilm growth is favoured by higher pH; whilst the processes are considerably retarded at lower pH values. The capabilities of the model to predict microbial respiration in a fully coupled multiphase flow condition and microbial fermentation leading to production of a gas phase are also demonstrated.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.015
      Issue No: Vol. 116 (2018)
  • Resilience-based performance metrics for water resources management under
    • Authors: Tom Roach; Zoran Kapelan; Ralph Ledbetter
      Pages: 18 - 28
      Abstract: Publication date: June 2018
      Source:Advances in Water Resources, Volume 116
      Author(s): Tom Roach, Zoran Kapelan, Ralph Ledbetter
      This paper aims to develop new, resilience type metrics for long-term water resources management under uncertain climate change and population growth. Resilience is defined here as the ability of a water resources management system to ‘bounce back’, i.e. absorb and then recover from a water deficit event, restoring the normal system operation. Ten alternative metrics are proposed and analysed addressing a range of different resilience aspects including duration, magnitude, frequency and volume of related water deficit events. The metrics were analysed on a real-world case study of the Bristol Water supply system in the UK and compared with current practice. The analyses included an examination of metrics’ sensitivity and correlation, as well as a detailed examination into the behaviour of metrics during water deficit periods. The results obtained suggest that multiple metrics which cover different aspects of resilience should be used simultaneously when assessing the resilience of a water resources management system, leading to a more complete understanding of resilience compared with current practice approaches. It was also observed that calculating the total duration of a water deficit period provided a clearer and more consistent indication of system performance compared to splitting the deficit periods into the time to reach and time to recover from the worst deficit events.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.016
      Issue No: Vol. 116 (2018)
  • Micro-positron emission tomography for measuring sub-core scale single and
           multiphase transport parameters in porous media
    • Authors: Christopher Zahasky; Sally M. Benson
      Pages: 1 - 16
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Christopher Zahasky, Sally M. Benson
      Accurate descriptions of heterogeneity in porous media are important for understanding and modeling single phase (e.g. contaminant transport, saltwater intrusion) and multiphase (e.g. geologic carbon storage, enhanced oil recovery) transport problems. Application of medical imaging to experimentally quantify these processes has led to significant progress in material characterization and understanding fluid transport behavior at laboratory scales. While widely utilized in cancer diagnosis and management, cardiology, and neurology, positron emission tomography (PET) has had relatively limited applications in earth science. This study utilizes a small-bore micro-PET scanner to image and quantify the transport behavior of pulses of a conservative aqueous radiotracer injected during single and multiphase flow experiments in two heterogeneous Berea sandstone cores. The cores are discretized into axial-parallel streamtubes, and using the reconstructed micro-PET data, expressions are derived from spatial moment analysis for calculating sub-core tracer flux and pore water velocity. Using the flux and velocity measurements, it is possible to calculate porosity and saturation from volumetric flux balance, and calculate permeability and water relative permeability from Darcy’s law. Second spatial moment analysis enables measurement of sub-core solute dispersion during both single phase and multiphase experiments. A numerical simulation model is developed to verify the assumptions of the streamtube dimension reduction technique. A variation of the reactor ratio is presented as a diagnostic metric to efficiently determine the validity of the streamtube approximation in core and column-scale experiments. This study introduces a new method to quantify sub-core permeability, relative permeability, and dispersion. These experimental and analytical methods provide a foundation for future work on experimental measurements of differences in transport behavior across scales.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.002
      Issue No: Vol. 115 (2018)
  • Entrainment, transport and deposition of sediment by saline gravity
    • Authors: Jessica Zordan; Carmelo Juez; Anton J. Schleiss; Mário J. Franca
      Pages: 17 - 32
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Jessica Zordan, Carmelo Juez, Anton J. Schleiss, Mário J. Franca
      Few studies have addressed simultaneously the feedback between the hydrodynamics of a gravity current and the geomorphological changes of a mobile bed. Hydrodynamic quantities such as turbulent and mean velocities, bed shear stress and turbulent stresses undoubtedly govern the processes of entrainment, transport and deposition. On the other hand, the incorporation of entrained sediment in the current may change its momentum by introducing extra internal stresses, introducing thus a feedback process. These two main questions are here investigated. Laboratory experiments of saline gravity currents, produced by lock-exchange, flowing over a mobile bed channel reach, are here reported. Different initial buoyancies of the current in the lock are tested together with three different grain sizes of the non-coherent sediment that form the erodible bed. Results from velocity measurements are combined with the visualization of the sediment movement in the mobile reach and with post-test topographic and photo surveys of the geomorphology modifications of the channel bed. Mean and turbulent velocities are measured and bed shear stress and Reynolds stresses are estimated. We show that the mean vertical component of the velocity and bed shear stress are highly correlated with the first instants of sediment entrainment. Vertical turbulent velocity is similarly related to entrainment, although with lower correlation values, contributing as well to the sediment movement. Bed shear stress and Reynolds shear stress measured near the bed are correlated with sediment entrainment for longer periods, indicating that these quantities are associated to distal transport as well. Geomorphological changes in the mobile bed are strongly related to the impulse caused by the bed shear stress on the sediment. On the other hand, we show that the nature of the grain of the mobile bed reach influences the hydrodynamics of the current which means that a feedback mechanisms between both occurs during the passage of the unsteady gravity current. The signature of this geomorphological changes, which is visible in the form of longitudinal steaks of accumulated sediment downstream the mobile bed, is related to the flow initial buoyancy and to the size of the mobile bed sediment. It is argued that the bed material and near-bed turbulent coherent motion interact and mutually influence each other. The geometry of the front of the gravity currents changes with the incorporation of the sediment, indicating that with the presence of sediment extra energy losses occur in the front of the current.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.02.017
      Issue No: Vol. 115 (2018)
  • Visualization of gas dissolution following upward gas migration in porous
           media: Technique and implications for stray gas
    • Authors: C.J.C. Van De Ven; Kevin G. Mumford
      Pages: 33 - 43
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): C.J.C. Van De Ven, Kevin G. Mumford
      The study of gas-water mass transfer in porous media is important in many applications, including unconventional resource extraction, carbon storage, deep geological waste storage, and remediation of contaminated groundwater, all of which rely on an understanding of the fate and transport of free and dissolved gas. The novel visual technique developed in this study provided both quantitative and qualitative observations of gas-water mass transfer. Findings included interaction between free gas architecture and dissolved plume migration, plume geometry and longevity. The technique was applied to the injection of CO2 in source patterns expected for stray gas originating from oil and gas operations to measure dissolved phase concentrations of CO2 at high spatial and temporal resolutions. The data set is the first of its kind to provide high resolution quantification of gas-water dissolution, and will facilitate an improved understanding of the fundamental processes of gas movement and fate in these complex systems.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.02.015
      Issue No: Vol. 115 (2018)
  • Morphological resilience to flow fluctuations of fine sediment deposits in
           bank lateral cavities
    • Authors: C. Juez; M. Thalmann; A.J. Schleiss; M.J. Franca
      Pages: 44 - 59
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): C. Juez, M. Thalmann, A.J. Schleiss, M.J. Franca
      Lateral cavities are built in the banks of rivers for several purposes: to create harbors, to capture sediment, to keep a central navigable channel (i.e., Casiers de Girardon in the Rhone river) or to promote the formation of aquatic habitats if a limited amount of sediment is captured, providing hydraulic and morphologic diversity (i.e., the case of Japanese Wandos). This work is focused on this latter purpose: promotion of hydraulic and morphologic diversity. In these scenarios, an increase in the flow discharge in the main channel may, however, re-mobilize the deposit of sediment inside these lateral embayments and cause a sudden increase of the sediment concentration and turbidity in the main channel. It is thus of interest to characterize the resistance and resilience of these sedimentary deposits when the main channel is subjected to high flow or flushing events. Laboratory tests were carried out for five different normalized geometries of the cavities installed in the banks of an open channel and for five hydrographs with different levels of unsteadiness. Water depth, sediment deposit mass, sediment concentration and area covered by the settled sediments were recorded throughout each experiment. Although sediment deposits established at equilibrium before the flushing events are different depending on the geometry of the cavities, generally, they are recovered after being flushed by the high flow events. It is shown that the resistance and resilience of the sediment deposits are strongly dependent on the flow field and the mass exchange between the main channel and the cavities. This mass exchange is governed by the geometry of the cavities and the magnitude of the hydrographs applied.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.004
      Issue No: Vol. 115 (2018)
  • Determination of the diffusivity, dispersion, skewness and kurtosis in
           heterogeneous porous flow. Part I: Analytical solutions with the extended
           method of moments.
    • Authors: Irina Ginzburg; Alexander Vikhansky
      Pages: 60 - 87
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Irina Ginzburg, Alexander Vikhansky
      The extended method of moments (EMM) is elaborated in recursive algorithmic form for the prediction of the effective diffusivity, the Taylor dispersion dyadic and the associated longitudinal high-order coefficients in mean-concentration profiles and residence-time distributions. The method applies in any streamwise-periodic stationary d-dimensional velocity field resolved in the piecewise continuous heterogeneous porosity field. It is demonstrated that EMM reduces to the method of moments and the volume-averaging formulation in microscopic velocity field and homogeneous soil, respectively. The EMM simultaneously constructs two systems of moments, the spatial and the temporal, without resorting to solving of the high-order upscaled PDE. At the same time, the EMM is supported with the reconstruction of distribution from its moments, allowing to visualize the deviation from the classical ADE solution. The EMM can be handled by any linear advection-diffusion solver with explicit mass-source and diffusive-flux jump condition on the solid boundary and permeable interface. The prediction of the first four moments is decisive in the optimization of the dispersion, asymmetry, peakedness and heavy-tails of the solute distributions, through an adequate design of the composite materials, wetlands, chemical devices or oil recovery. The symbolic solutions for dispersion, skewness and kurtosis are constructed in basic configurations: diffusion process and Darcy flow through two porous blocks in “series”, straight and radial Poiseuille flow, porous flow governed by the Stokes–Brinkman–Darcy channel equation and a fracture surrounded by penetrable diffusive matrix or embedded in porous flow. We examine the moments dependency upon porosity contrast, aspect ratio, Péclet and Darcy numbers, but also for their response on the effective Brinkman viscosity applied in flow modeling. Two numerical Lattice Boltzmann algorithms, a direct solver of the microscopic ADE in heterogeneous structure and a novel scheme for EMM numerical formulation, are called for validation of the constructed analytical predictions.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2017.12.005
      Issue No: Vol. 115 (2018)
  • Estimation of relative permeability and capillary pressure from mass
           imbibition experiments
    • Authors: Nayef Alyafei; Martin J. Blunt
      Pages: 88 - 94
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Nayef Alyafei, Martin J. Blunt
      We perform spontaneous imbibition experiments on three carbonates - Estaillades, Ketton, and Portland - which are three quarry limestones that have very different pore structures and span wide range of permeability. We measure the mass of water imbibed in air saturated cores as a function of time under strongly water-wet conditions. Specifically, we perform co-current spontaneous experiments using a highly sensitive balance to measure the mass imbibed as a function of time for the three rocks. We use cores measuring 37 mm in diameter and three lengths of approximately 76 mm, 204 mm, and 290 mm. We show that the amount imbibed scales as the square root of time and find the parameter C, where the volume imbibed per unit cross-sectional area at time t is Ct 1/2. We find higher C values for higher permeability rocks. Employing semi-analytical solutions for one-dimensional flow and using reasonable estimates of relative permeability and capillary pressure, we can match the experimental data. We finally discuss how, in combination with conventional measurements, we can use theoretical solutions and imbibition measurements to find or constrain relative permeability and capillary pressure.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.003
      Issue No: Vol. 115 (2018)
  • Fluid flow simulation and permeability computation in deformed porous
           carbonate grainstones
    • Authors: Miller Zambrano; Emanuele Tondi; Lucia Mancini; Gabriele Lanzafame; F. Xavier Trias; Fabio Arzilli; Marco Materazzi; Stefano Torrieri
      Pages: 95 - 111
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Miller Zambrano, Emanuele Tondi, Lucia Mancini, Gabriele Lanzafame, F. Xavier Trias, Fabio Arzilli, Marco Materazzi, Stefano Torrieri
      In deformed porous carbonates, the architecture of the pore network may be modified by deformation or diagenetic processes altering the permeability with respect to the pristine rock. The effects of the pore texture and morphology on permeability in porous rocks have been widely investigated due to the importance during the evaluation of geofluid reservoirs. In this study, these effects are assessed by combining synchrotron X-ray computed microtomography (SR micro-CT) and computational fluid dynamics. The studied samples pertain to deformed porous carbonate grainstones highly affected by deformation bands (DBs) exposed in Northwestern Sicily and Abruzzo regions, Italy. The high-resolution SR micro-CT images of the samples, acquired at the SYRMEP beamline of the Elettra - Sincrotrone Trieste laboratory (Italy), were used for simulating a pressure-driven flow by using the lattice-Boltzmann method (LBM). For the experiments, a multiple relaxation time (MRT) model with the D3Q19 scheme was used to avoid viscosity-dependent results of permeability. The permeability was calculated using Darcy's law once steady conditions were reached. After the simulations, the pore-network properties (effective porosity, specific surface area, and geometrical tortuosity) were calculated using 3D images of the velocity fields. These images were segmented considering a velocity threshold value higher than zero. The study showed that DBs may generate significant heterogeneity and anisotropy of the permeability of the evaluated rock samples. Cataclasis and cementation process taking place within the DBs reduce the effective porosity and therefore the permeability. Contrary to this, pressure dissolution and faulting may generate connected channels which contribute to the permeability only parallel to the DB.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.02.016
      Issue No: Vol. 115 (2018)
  • Optimization of image quality and acquisition time for lab-based X-ray
           microtomography using an iterative reconstruction algorithm
    • Authors: Qingyang Lin; Matthew Andrew; William Thompson; Martin J. Blunt; Branko Bijeljic
      Pages: 112 - 124
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Qingyang Lin, Matthew Andrew, William Thompson, Martin J. Blunt, Branko Bijeljic
      Non-invasive laboratory-based X-ray microtomography has been widely applied in many industrial and research disciplines. However, the main barrier to the use of laboratory systems compared to a synchrotron beamline is its much longer image acquisition time (hours per scan compared to seconds to minutes at a synchrotron), which results in limited application for dynamic in situ processes. Therefore, the majority of existing laboratory X-ray microtomography is limited to static imaging; relatively fast imaging (tens of minutes per scan) can only be achieved by sacrificing imaging quality, e.g. reducing exposure time or number of projections. To alleviate this barrier, we introduce an optimized implementation of a well-known iterative reconstruction algorithm that allows users to reconstruct tomographic images with reasonable image quality, but requires lower X-ray signal counts and fewer projections than conventional methods. Quantitative analysis and comparison between the iterative and the conventional filtered back-projection reconstruction algorithm was performed using a sandstone rock sample with and without liquid phases in the pore space. Overall, by implementing the iterative reconstruction algorithm, the required image acquisition time for samples such as this, with sparse object structure, can be reduced by a factor of up to 4 without measurable loss of sharpness or signal to noise ratio.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.007
      Issue No: Vol. 115 (2018)
  • An adaptive Gaussian process-based iterative ensemble smoother for data
    • Authors: Lei Ju; Jiangjiang Zhang; Long Meng; Laosheng Wu; Lingzao Zeng
      Pages: 125 - 135
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Lei Ju, Jiangjiang Zhang, Long Meng, Laosheng Wu, Lingzao Zeng
      Accurate characterization of subsurface hydraulic conductivity is vital for modeling of subsurface flow and transport. The iterative ensemble smoother (IES) has been proposed to estimate the heterogeneous parameter field. As a Monte Carlo-based method, IES requires a relatively large ensemble size to guarantee its performance. To improve the computational efficiency, we propose an adaptive Gaussian process (GP)-based iterative ensemble smoother (GPIES) in this study. At each iteration, the GP surrogate is adaptively refined by adding a few new base points chosen from the updated parameter realizations. Then the sensitivity information between model parameters and measurements is calculated from a large number of realizations generated by the GP surrogate with virtually no computational cost. Since the original model evaluations are only required for base points, whose number is much smaller than the ensemble size, the computational cost is significantly reduced. The applicability of GPIES in estimating heterogeneous conductivity is evaluated by the saturated and unsaturated flow problems, respectively. Without sacrificing estimation accuracy, GPIES achieves about an order of magnitude of speed-up compared with the standard IES. Although subsurface flow problems are considered in this study, the proposed method can be equally applied to other hydrological models.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.010
      Issue No: Vol. 115 (2018)
  • Porous gravity currents: Axisymmetric propagation in horizontally graded
           medium and a review of similarity solutions
    • Authors: I. Lauriola; G. Felisa; D. Petrolo; V. Di Federico; S. Longo
      Pages: 136 - 150
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): I. Lauriola, G. Felisa, D. Petrolo, V. Di Federico, S. Longo
      We present an investigation on the combined effect of fluid rheology and permeability variations on the propagation of porous gravity currents in axisymmetric geometry. The fluid is taken to be of power-law type with behaviour index n and the permeability to depend from the distance from the source as a power-law function of exponent β. The model represents the injection of a current of non-Newtonian fluid along a vertical bore hole in porous media with space-dependent properties. The injection is either instantaneous ( α = 0 ) or continuous (α > 0). A self-similar solution describing the rate of propagation and the profile of the current is derived under the assumption of small aspect ratio between the current average thickness and length. The limitations on model parameters imposed by the model assumptions are discussed in depth, considering currents of increasing/decreasing velocity, thickness, and aspect ratio, and the sensitivity of the radius, thickness, and aspect ratio to model parameters. Several critical values of α and β discriminating between opposite tendencies are thus determined. Experimental validation is performed using shear-thinning suspensions and Newtonian mixtures in different regimes. A box filled with ballotini of different diameter is used to reproduce the current, with observations from the side and bottom. Most experimental results for the radius and profile of the current agree well with the self-similar solution except at the beginning of the process, due to the limitations of the 2-D assumption and to boundary effects near the injection zone. The results for this specific case corroborate a general model for currents with constant or time-varying volume of power-law fluids propagating in porous domains of plane or radial geometry, with uniform or varying permeability, and the possible effect of channelization. All results obtained in the present and previous papers for the key parameters governing the dynamics of power-law gravity currents are summarized and compared to infer the combinations of parameters leading to the fastest/lowest rate of propagation, and of variation of thickness and aspect ratio.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.008
      Issue No: Vol. 115 (2018)
  • Impact of microstructure evolution on the difference between geometric and
           reactive surface areas in natural chalk
    • Authors: Y. Yang; S. Bruns; S.L.S. Stipp; H.O. Sørensen
      Pages: 151 - 159
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Y. Yang, S. Bruns, S.L.S. Stipp, H.O. Sørensen
      The coupling between flow and mineral dissolution drives the evolution of many natural and engineered flow systems. Pore surface changes as microstructure evolves but this transient behaviour has traditionally been difficult to model. We combined a reactor network model with experimental, greyscale tomography data to establish the morphological grounds for differences among geometric, reactive and apparent surface areas in dissolving chalk. This approach allowed us to study the effects of initial geometry and macroscopic flow rate independently. The simulations showed that geometric surface, which represents a form of local transport heterogeneity, increases in an imposed flow field, even when the porous structure is chemically homogeneous. Hence, the fluid-reaction coupling leads to solid channelisation, which further results in fluid focusing and an increase in geometric surface area. Fluid focusing decreases the area of reactive surface and the residence time of reactant, both contribute to the over-normalisation of reaction rate. In addition, the growing and merging of microchannels, near the fluid entrance, contribute to the macroscopic, fast initial dissolution rate of rocks.
      Graphical abstract image

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.005
      Issue No: Vol. 115 (2018)
  • Explicit treatment for Dirichlet, Neumann and Cauchy boundary conditions
           in POD-based reduction of groundwater models
    • Authors: Moritz Gosses; Wolfgang Nowak; Thomas Wöhling
      Pages: 160 - 171
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Moritz Gosses, Wolfgang Nowak, Thomas Wöhling
      In recent years, proper orthogonal decomposition (POD) has become a popular model reduction method in the field of groundwater modeling. It is used to mitigate the problem of long run times that are often associated with physically-based modeling of natural systems, especially for parameter estimation and uncertainty analysis. POD-based techniques reproduce groundwater head fields sufficiently accurate for a variety of applications. However, no study has investigated how POD techniques affect the accuracy of different boundary conditions found in groundwater models. We show that the current treatment of boundary conditions in POD causes inaccuracies for these boundaries in the reduced models. We provide an improved method that splits the POD projection space into a subspace orthogonal to the boundary conditions and a separate subspace that enforces the boundary conditions. To test the method for Dirichlet, Neumann and Cauchy boundary conditions, four simple transient 1D-groundwater models, as well as a more complex 3D model, are set up and reduced both by standard POD and POD with the new extension. We show that, in contrast to standard POD, the new method satisfies both Dirichlet and Neumann boundary conditions. It can also be applied to Cauchy boundaries, where the flux error of standard POD is reduced by its head-independent contribution. The extension essentially shifts the focus of the projection towards the boundary conditions. Therefore, we see a slight trade-off between errors at model boundaries and overall accuracy of the reduced model. The proposed POD extension is recommended where exact treatment of boundary conditions is required.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.011
      Issue No: Vol. 115 (2018)
  • Positivity-preserving well-balanced discontinuous Galerkin methods for the
           shallow water flows in open channels
    • Authors: Shouguo Qian; Gang Li; Fengjing Shao; Yulong Xing
      Pages: 172 - 184
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Shouguo Qian, Gang Li, Fengjing Shao, Yulong Xing
      We construct and study efficient high order discontinuous Galerkin methods for the shallow water flows in open channels with irregular geometry and a non-flat bottom topography in this paper. The proposed methods are well-balanced for the still water steady state solution, and can preserve the non-negativity of wet cross section numerically. The well-balanced property is obtained via a novel source term separation and discretization. A simple positivity-preserving limiter is employed to provide efficient and robust simulations near the wetting and drying fronts. Numerical examples are performed to verify the well-balanced property, the non-negativity of the wet cross section, and good performance for both continuous and discontinuous solutions.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.001
      Issue No: Vol. 115 (2018)
  • A 1D–2D coupled SPH-SWE model applied to open channel flow simulations
           in complicated geometries
    • Authors: Kao-Hua Chang; Tony Wen-Hann Sheu; Tsang-Jung Chang
      Pages: 185 - 197
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Kao-Hua Chang, Tony Wen-Hann Sheu, Tsang-Jung Chang
      In this study, a one- and two-dimensional (1D–2D) coupled model is developed to solve the shallow water equations (SWEs). The solutions are obtained using a Lagrangian meshless method called smoothed particle hydrodynamics (SPH) to simulate shallow water flows in converging, diverging and curved channels. A buffer zone is introduced to exchange information between the 1D and 2D SPH-SWE models. Interpolated water discharge values and water surface levels at the internal boundaries are prescribed as the inflow/outflow boundary conditions in the two SPH-SWE models. In addition, instead of using the SPH summation operator, we directly solve the continuity equation by introducing a diffusive term to suppress oscillations in the predicted water depth. The performance of the two approaches in calculating the water depth is comprehensively compared through a case study of a straight channel. Additionally, three benchmark cases involving converging, diverging and curved channels are adopted to demonstrate the ability of the proposed 1D and 2D coupled SPH-SWE model through comparisons with measured data and predicted mesh-based numerical results. The proposed model provides satisfactory accuracy and guaranteed convergence.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.009
      Issue No: Vol. 115 (2018)
  • Revisitation of the dipole tracer test for heterogeneous porous formations
    • Authors: Alraune Zech; Claudia D’Angelo; Sabine Attinger; Aldo Fiori
      Pages: 198 - 206
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Alraune Zech, Claudia D’Angelo, Sabine Attinger, Aldo Fiori
      In this paper, a new analytical solution for interpreting dipole tests in heterogeneous media is derived by associating the shape of the tracer breakthrough curve with the log-conductivity variance. It is presented how the solution can be used for interpretation of dipole field test in view of geostatistical aquifer characterization on three illustrative examples. The analytical solution for the tracer breakthrough curve at the pumping well in a dipole tracer test is developed by considering a perfectly stratified formation. The analysis is carried out making use of the travel time of a generic solute particle, from the injection to the pumping well. Injection conditions are adapted to different possible field setting. Solutions are presented for resident and flux proportional injection mode as well as for an instantaneous pulse of solute and continuous solute injections. The analytical form of the solution allows a detailed investigation on the impact of heterogeneity, the tracer input conditions and ergodicity conditions at the well. The impact of heterogeneity manifests in a significant spreading of solute particles that increases the natural tendency to spreading induced by the dipole setup. Furthermore, with increasing heterogeneity the number of layers needed to reach ergodic conditions become larger. Thus, dipole test in highly heterogeneous aquifers might take place under non-ergodic conditions giving that the log-conductivity variance is underestimated. The method is a promising geostatistical analyzing tool being the first analytical solution for dipole tracer test analysis taking heterogeneity of hydraulic conductivity into account.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.006
      Issue No: Vol. 115 (2018)
  • Evaluation of a numerical model's ability to predict bed load transport
           observed in braided river experiments
    • Authors: Luke Javernick; Marco Redolfi; Walter Bertoldi
      Pages: 207 - 218
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Luke Javernick, Marco Redolfi, Walter Bertoldi
      New data collection techniques offer numerical modelers the ability to gather and utilize high quality data sets with high spatial and temporal resolution. Such data sets are currently needed for calibration, verification, and to fuel future model development, particularly morphological simulations. This study explores the use of high quality spatial and temporal data sets of observed bed load transport in braided river flume experiments to evaluate the ability of a two-dimensional model, Delft3D, to predict bed load transport. This study uses a fixed bed model configuration and examines the model's shear stress calculations, which are the foundation to predict the sediment fluxes necessary for morphological simulations. The evaluation is conducted for three flow rates, and model setup used highly accurate Structure-from-Motion (SfM) topography and discharge boundary conditions. The model was hydraulically calibrated using bed roughness, and performance was evaluated based on depth and inundation agreement. Model bed load performance was evaluated in terms of critical shear stress exceedance area compared to maps of observed bed mobility in a flume. Following the standard hydraulic calibration, bed load performance was tested for sensitivity to horizontal eddy viscosity parameterization and bed morphology updating. Simulations produced depth errors equal to the SfM inherent errors, inundation agreement of 77–85%, and critical shear stress exceedance in agreement with 49–68% of the observed active area. This study provides insight into the ability of physically based, two-dimensional simulations to accurately predict bed load as well as the effects of horizontal eddy viscosity and bed updating. Further, this study highlights how using high spatial and temporal data to capture the physical processes at work during flume experiments can help to improve morphological modeling.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.012
      Issue No: Vol. 115 (2018)
  • The 1D Richards’ equation in two layered soils: a Filippov approach
           to treat discontinuities
    • Authors: Marco Berardi; Fabio Difonzo; Michele Vurro; Luciano Lopez
      Pages: 264 - 272
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Marco Berardi, Fabio Difonzo, Michele Vurro, Luciano Lopez
      The infiltration process into the soil is generally modeled by the Richards’ partial differential equation (PDE). In this paper a new approach for modeling the infiltration process through the interface of two different soils is proposed, where the interface is seen as a discontinuity surface defined by suitable state variables. Thus, the original 1D Richards’ PDE, enriched by a particular choice of the boundary conditions, is first approximated by means of a time semidiscretization, that is by means of the transversal method of lines (TMOL). In such a way a sequence of discontinuous initial value problems, described by a sequence of second order differential systems in the space variable, is derived. Then, Filippov theory on discontinuous dynamical systems may be applied in order to study the relevant dynamics of the problem. The numerical integration of the semidiscretized differential system will be performed by using a one-step method, which employs an event driven procedure to locate the discontinuity surface and to adequately change the vector field.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2017.09.027
      Issue No: Vol. 115 (2018)
  • A well-balanced meshless tsunami propagation and inundation model
    • Authors: Rüdiger Brecht; Alexander Bihlo; Scott MacLachlan; Jörn Behrens
      Pages: 273 - 285
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Rüdiger Brecht, Alexander Bihlo, Scott MacLachlan, Jörn Behrens
      We present a novel meshless tsunami propagation and inundation model. We discretize the nonlinear shallow-water equations using a well-balanced scheme relying on radial basis function based finite differences. For the inundation model, radial basis functions are used to extrapolate the dry region from nearby wet points. Numerical results against standard one- and two-dimensional benchmarks are presented.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2017.12.013
      Issue No: Vol. 115 (2018)
  • A two-phase flow model for submarine granular flows: With an application
           to collapse of deeply-submerged granular columns
    • Authors: Cheng-Hsien Lee; Zhenhua Huang
      Pages: 286 - 300
      Abstract: Publication date: May 2018
      Source:Advances in Water Resources, Volume 115
      Author(s): Cheng-Hsien Lee, Zhenhua Huang
      The collapse process of a submerged granular column is strongly affected by its initial packing. Previous models for particle response time, which is used to quantify the drag force between the solid and liquid phases in rheology-based two-phase flow models, have difficulty in simulating the collapse process of granular columns with different initial concentrations (initial packing conditions). This study introduces a new model for particle response time, which enables us to satisfactorily model the drag force between the two phases for a wide range of volume concentration. The present model can give satisfactory results for both loose and dense packing conditions. The numerical results have shown that (i) the initial packing affects the occurrence of contractancy/diltancy behavior during the collapse process, (ii) the general buoyancy and drag force are strongly affected by the initial packing through contractancy and diltancy, and (iii) the general buoyancy and drag force can destabilize the granular material in loose packing condition but stabilize the granular material in dense packing condition. The results have shown that the collapse process of a densely-packed granular column is more sensitive to particle response time than that of a loosely-packed granular column.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2017.12.012
      Issue No: Vol. 115 (2018)
  • Determining water storage depletion within Iran by assimilating GRACE data
           into the W3RA hydrological model
    • Authors: M. Khaki; E. Forootan; M. Kuhn; J. Awange; A.I.J.M. van Dijk; M. Schumacher; M.A. Sharifi
      Pages: 1 - 18
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): M. Khaki, E. Forootan, M. Kuhn, J. Awange, A.I.J.M. van Dijk, M. Schumacher, M.A. Sharifi
      Groundwater depletion, due to both unsustainable water use and a decrease in precipitation, has been reported in many parts of Iran. In order to analyze these changes during the recent decade, in this study, we assimilate Terrestrial Water Storage (TWS) data from the Gravity Recovery And Climate Experiment (GRACE) into the World-Wide Water Resources Assessment (W3RA) model. This assimilation improves model derived water storage simulations by introducing missing trends and correcting the amplitude and phase of seasonal water storage variations. The Ensemble Square-Root Filter (EnSRF) technique is applied, which showed stable performance in propagating errors during the assimilation period (2002–2012). Our focus is on sub-surface water storage changes including groundwater and soil moisture variations within six major drainage divisions covering the whole Iran including its eastern part (East), Caspian Sea, Centre, Sarakhs, Persian Gulf and Oman Sea, and Lake Urmia. Results indicate an average of -8.9 mm/year groundwater reduction within Iran during the period 2002 to 2012. A similar decrease is also observed in soil moisture storage especially after 2005. We further apply the canonical correlation analysis (CCA) technique to relate sub-surface water storage changes to climate (e.g., precipitation) and anthropogenic (e.g., farming) impacts. Results indicate an average correlation of 0.81 between rainfall and groundwater variations and also a large impact of anthropogenic activities (mainly for irrigations) on Iran’s water storage depletions.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.008
      Issue No: Vol. 114 (2018)
  • Algebraic multigrid preconditioners for two-phase flow in porous media
           with phase transitions
    • Authors: Quan M. Bui; Lu Wang; Daniel Osei-Kuffuor
      Pages: 19 - 28
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Quan M. Bui, Lu Wang, Daniel Osei-Kuffuor
      Multiphase flow is a critical process in a wide range of applications, including oil and gas recovery, carbon sequestration, and contaminant remediation. Numerical simulation of multiphase flow requires solving of a large, sparse linear system resulting from the discretization of the partial differential equations modeling the flow. In the case of multiphase multicomponent flow with miscible effect, this is a very challenging task. The problem becomes even more difficult if phase transitions are taken into account. A new approach to handle phase transitions is to formulate the system as a nonlinear complementarity problem (NCP). Unlike in the primary variable switching technique, the set of primary variables in this approach is fixed even when there is phase transition. Not only does this improve the robustness of the nonlinear solver, it opens up the possibility to use multigrid methods to solve the resulting linear system. The disadvantage of the complementarity approach, however, is that when a phase disappears, the linear system has the structure of a saddle point problem and becomes indefinite, and current algebraic multigrid (AMG) algorithms cannot be applied directly. In this study, we explore the effectiveness of a new multilevel strategy, based on the multigrid reduction technique, to deal with problems of this type. We demonstrate the effectiveness of the method through numerical results for the case of two-phase, two-component flow with phase appearance/disappearance. We also show that the strategy is efficient and scales optimally with problem size.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.01.027
      Issue No: Vol. 114 (2018)
  • Reservoir simulation with the cubic plus (cross-) association equation of
           state for water, CO2, hydrocarbons, and tracers
    • Authors: Joachim Moortgat
      Pages: 29 - 44
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Joachim Moortgat
      This work presents an efficient reservoir simulation framework for multicomponent, multiphase, compressible flow, based on the cubic-plus-association (CPA) equation of state (EOS). CPA is an accurate EOS for mixtures that contain non-polar hydrocarbons, self-associating polar water, and cross-associating molecules like methane, ethane, unsaturated hydrocarbons, CO2, and H2S. While CPA is accurate, its mathematical formulation is highly non-linear, resulting in excessive computational costs that have made the EOS unfeasible for large scale reservoir simulations. This work presents algorithms that overcome these bottlenecks and achieve an efficiency comparable to the much simpler cubic EOS approach. The main applications that require such accurate phase behavior modeling are 1) the study of methane leakage from high-pressure production wells and its potential impact on groundwater resources, 2) modeling of geological CO2 sequestration in brine aquifers when one is interested in more than the CO2 and H2O components, e.g. methane, other light hydrocarbons, and various tracers, and 3) enhanced oil recovery by CO2 injection in reservoirs that have previously been waterflooded or contain connate water. We present numerical examples of all those scenarios, extensive validation of the CPA EOS with experimental data, and analyses of the efficiency of our proposed numerical schemes. The accuracy, efficiency, and robustness of the presented phase split computations pave the way to more widespread adoption of CPA in reservoir simulators.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.004
      Issue No: Vol. 114 (2018)
  • A residual-based shock capturing scheme for the continuous/discontinuous
           spectral element solution of the 2D shallow water equations
    • Authors: Simone Marras; Michal A. Kopera; Emil M. Constantinescu; Jenny Suckale; Francis X. Giraldo
      Pages: 45 - 63
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Simone Marras, Michal A. Kopera, Emil M. Constantinescu, Jenny Suckale, Francis X. Giraldo
      The high-order numerical solution of the non-linear shallow water equations is susceptible to Gibbs oscillations in the proximity of strong gradients. In this paper, we tackle this issue by presenting a shock capturing model based on the numerical residual of the solution. Via numerical tests, we demonstrate that the model removes the spurious oscillations in the proximity of strong wave fronts while preserving their strength. Furthermore, for coarse grids, it prevents energy from building up at small wave-numbers. When applied to the continuity equation to stabilize the water surface, the addition of the shock capturing scheme does not affect mass conservation. We found that our model improves the continuous and discontinuous Galerkin solutions alike in the proximity of sharp fronts propagating on wet surfaces. In the presence of wet/dry interfaces, however, the model needs to be enhanced with the addition of an inundation scheme which, however, we do not address in this paper.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.003
      Issue No: Vol. 114 (2018)
  • A phase-field lattice Boltzmann model for simulating multiphase flows in
           porous media: Application and comparison to experiments of CO2
           sequestration at pore scale
    • Authors: Abbas Fakhari; Yaofa Li; Diogo Bolster; Kenneth T. Christensen
      Pages: 119 - 134
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Abbas Fakhari, Yaofa Li, Diogo Bolster, Kenneth T. Christensen
      We implement a phase-field based lattice-Boltzmann (LB) method for numerical simulation of multiphase flows in heterogeneous porous media at pore scales with wettability effects. The present method can handle large density and viscosity ratios, pertinent to many practical problems. As a practical application, we study multiphase flow in a micromodel representative of CO2 invading a water-saturated porous medium at reservoir conditions, both numerically and experimentally. We focus on two flow cases with (i) a crossover from capillary fingering to viscous fingering at a relatively small capillary number, and (ii) viscous fingering at a relatively moderate capillary number. Qualitative and quantitative comparisons are made between numerical results and experimental data for temporal and spatial CO2 saturation profiles, and good agreement is found. In particular, a correlation analysis shows that any differences between simulations and results are comparable to intra-experimental differences from replicate experiments. A key conclusion of this work is that system behavior is highly sensitive to boundary conditions, particularly inlet and outlet ones. We finish with a discussion on small-scale flow features, such as the emergence of strong recirculation zones as well as flow in which the residual phase is trapped, including a close look at the detailed formation of a water cone. Overall, the proposed model yields useful information, such as the spatiotemporal evolution of the CO2 front and instantaneous velocity fields, which are valuable for understanding the mechanisms of CO2 infiltration at the pore scale.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.005
      Issue No: Vol. 114 (2018)
  • Rising tides, rising gates: The complex ecogeomorphic response of coastal
           wetlands to sea-level rise and human interventions
    • Authors: Steven G. Sandi; José F. Rodríguez; Neil Saintilan; Gerardo Riccardi; Patricia M. Saco
      Pages: 135 - 148
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Steven G. Sandi, José F. Rodríguez, Neil Saintilan, Gerardo Riccardi, Patricia M. Saco
      Coastal wetlands are vulnerable to submergence due to sea-level rise, as shown by predictions of up to 80% of global wetland loss by the end of the century. Coastal wetlands with mixed mangrove-saltmarsh vegetation are particularly vulnerable because sea-level rise can promote mangrove encroachment on saltmarsh, reducing overall wetland biodiversity. Here we use an ecogeomorphic framework that incorporates hydrodynamic effects, mangrove-saltmarsh dynamics, and soil accretion processes to assess the effects of control structures on wetland evolution. Migration and accretion patterns of mangrove and saltmarsh are heavily dependent on topography and control structures. We find that current management practices that incorporate a fixed gate for the control of mangrove encroachment are useful initially, but soon become ineffective due to sea-level rise. Raising the gate, to counteract the effects of sea level rise and promote suitable hydrodynamic conditions, excludes mangrove and maintains saltmarsh over the entire simulation period of 100 years

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.006
      Issue No: Vol. 114 (2018)
  • A hierarchy of models for simulating experimental results from a 3D
           heterogeneous porous medium
    • Authors: Daniel Vogler; Sassan Ostvar; Rebecca Paustian; Brian D. Wood
      Pages: 149 - 163
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Daniel Vogler, Sassan Ostvar, Rebecca Paustian, Brian D. Wood
      In this work we examine the dispersion of conservative tracers (bromide and fluorescein) in an experimentally-constructed three-dimensional dual-porosity porous medium. The medium is highly heterogeneous ( σ Y 2 = 5.7 ), and consists of spherical, low-hydraulic-conductivity inclusions embedded in a high-hydraulic-conductivity matrix. The bimodal medium was saturated with tracers, and then flushed with tracer-free fluid while the effluent breakthrough curves were measured. The focus for this work is to examine a hierarchy of four models (in the absence of adjustable parameters) with decreasing complexity to assess their ability to accurately represent the measured breakthrough curves. The most information-rich model was (1) a direct numerical simulation of the system in which the geometry, boundary and initial conditions, and medium properties were fully independently characterized experimentally with high fidelity. The reduced-information models included; (2) a simplified numerical model identical to the fully-resolved direct numerical simulation (DNS) model, but using a domain that was one-tenth the size; (3) an upscaled mobile-immobile model that allowed for a time-dependent mass-transfer coefficient; and, (4) an upscaled mobile-immobile model that assumed a space-time constant mass-transfer coefficient. The results illustrated that all four models provided accurate representations of the experimental breakthrough curves as measured by global RMS error. The primary component of error induced in the upscaled models appeared to arise from the neglect of convection within the inclusions. We discuss the necessity to assign value (via a utility function or other similar method) to outcomes if one is to further select from among model options. Interestingly, these results suggested that the conventional convection-dispersion equation, when applied in a way that resolves the heterogeneities, yields models with high fidelity without requiring the imposition of a more complex non-Fickian model.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.009
      Issue No: Vol. 114 (2018)
  • A New Moving Strategy for the Sequential Monte Carlo Approach in
           Optimizing the Hydrological Model Parameters
    • Authors: Gaofeng Zhu; Xin Li; Jinzhu Ma; Yunquan Wang; Shaomin Liu; Chunlin Huang; Kun Zhang; Xiaoli Hu
      Pages: 164 - 179
      Abstract: Publication date: Available online 13 February 2018
      Source:Advances in Water Resources
      Author(s): Gaofeng Zhu, Xin Li, Jinzhu Ma, Yunquan Wang, Shaomin Liu, Chunlin Huang, Kun Zhang, Xiaoli Hu
      Sequential Monte Carlo (SMC) samplers have become increasing popular for estimating the posterior parameter distribution with the non-linear dependency structures and multiple modes often present in hydrological models. However, the explorative capabilities and efficiency of the sampler depends strongly on the efficiency in the move step of SMC sampler. In this paper we presented a new SMC sampler entitled the Particle Evolution Metropolis Sequential Monte Carlo (PEM-SMC) algorithm, which is well suited to handle unknown static parameters of hydrologic model. The PEM-SMC sampler is inspired by the works of Liang and Wong (2001) and operates by incorporating the strengths of the genetic algorithm, differential evolution algorithm and Metropolis-Hasting algorithm into the framework of SMC. We also prove that the sampler admits the target distribution to be a stationary distribution. Two case studies including a multi-dimensional bimodal normal distribution and a conceptual rainfall-runoff hydrologic model by only considering parameter uncertainty and simultaneously considering parameter and input uncertainty show that PEM-SMC sampler is generally superior to other popular SMC algorithms in handling the high dimensional problems. The study also indicated that it may be important to account for model structural uncertainty by using multiplier different hydrological models in the SMC framework in future study.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.007
      Issue No: Vol. 114 (2018)
  • Monthly Hydroclimatology of the continental United States
    • Authors: Thomas Petersen; Naresh Devineni; A. Sankarasubramanian
      Pages: 180 - 195
      Abstract: Publication date: Available online 14 February 2018
      Source:Advances in Water Resources
      Author(s): Thomas Peterson, Naresh Devineni, A. Sankarasubramanian
      Physical/semi-empirical models that do not require any calibration are of paramount need for estimating hydrological fluxes for ungauged sites. We develop semi-empirical models for estimating the mean and variance of the monthly streamflow based on Taylor Series approximation of a lumped physically based water balance model. The proposed models require mean and variance of monthly precipitation and potential evapotranspiration, co-variability of precipitation and potential evapotranspiration and regionally calibrated catchment retention sensitivity, atmospheric moisture uptake sensitivity, groundwater-partitioning factor, and the maximum soil moisture holding capacity parameters. Estimates of mean and variance of monthly streamflow using the semi-empirical equations are compared with the observed estimates for 1373 catchments in the continental United States. Analyses show that the proposed models explain the spatial variability in monthly moments for basins in lower elevations. A regionalization of parameters for each water resources region show good agreement between observed moments and model estimated moments during January, February, March and April for mean and all months except May and June for variance. Thus, the proposed relationships could be employed for understanding and estimating the monthly hydroclimatology of ungauged basins using regional parameters.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.010
      Issue No: Vol. 114 (2018)
  • Groundwater flow and heat transport for systems undergoing freeze-thaw:
           Intercomparison of numerical simulators for 2D test cases
    • Authors: Christophe Grenier; Hauke Anbergen; Victor Bense; Quentin Chanzy; Ethan Coon; Nathaniel Collier; François Costard; Michel Ferry; Andrew Frampton; Jennifer Frederick; Julio Gonçalvès; Johann Holmén; Anne Jost; Samuel Kokh; Barret Kurylyk; Jeffrey McKenzie; John Molson; Emmanuel Mouche; Laurent Orgogozo; Romain Pannetier; Agnès Rivière; Nicolas Roux; Wolfram Rühaak; Johanna Scheidegger; Jan-Olof Selroos; René Therrien; Patrik Vidstrand; Clifford Voss
      Pages: 196 - 218
      Abstract: Publication date: April 2018
      Source:Advances in Water Resources, Volume 114
      Author(s): Christophe Grenier, Hauke Anbergen, Victor Bense, Quentin Chanzy, Ethan Coon, Nathaniel Collier, François Costard, Michel Ferry, Andrew Frampton, Jennifer Frederick, Julio Gonçalvès, Johann Holmén, Anne Jost, Samuel Kokh, Barret Kurylyk, Jeffrey McKenzie, John Molson, Emmanuel Mouche, Laurent Orgogozo, Romain Pannetier, Agnès Rivière, Nicolas Roux, Wolfram Rühaak, Johanna Scheidegger, Jan-Olof Selroos, René Therrien, Patrik Vidstrand, Clifford Voss
      In high-elevation, boreal and arctic regions, hydrological processes and associated water bodies can be strongly influenced by the distribution of permafrost. Recent field and modeling studies indicate that a fully-coupled multidimensional thermo-hydraulic approach is required to accurately model the evolution of these permafrost-impacted landscapes and groundwater systems. However, the relatively new and complex numerical codes being developed for coupled non-linear freeze-thaw systems require verification. This issue is addressed by means of an intercomparison of thirteen numerical codes for two-dimensional test cases with several performance metrics (PMs). These codes comprise a wide range of numerical approaches, spatial and temporal discretization strategies, and computational efficiencies. Results suggest that the codes provide robust results for the test cases considered and that minor discrepancies are explained by computational precision. However, larger discrepancies are observed for some PMs resulting from differences in the governing equations, discretization issues, or in the freezing curve used by some codes.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.02.001
      Issue No: Vol. 114 (2018)
  • Ill-posedness in modeling mixed sediment river morphodynamics
    • Authors: Víctor Chavarrías; Guglielmo Stecca; Astrid Blom
      Pages: 219 - 235
      Abstract: Publication date: Available online 16 February 2018
      Source:Advances in Water Resources
      Author(s): Víctor Chavarrías, Guglielmo Stecca, Astrid Blom
      In this paper we analyze the Hirano active layer model used in mixed sediment river morphodynamics concerning its ill-posedness. Ill-posedness causes the solution to be unstable to short-wave perturbations. This implies that the solution presents spurious oscillations, the amplitude of which depends on the domain discretization. Ill-posedness not only produces physically unrealistic results but may also cause failure of numerical simulations. By considering a two-fraction sediment mixture we obtain analytical expressions for the mathematical characterization of the model. Using these we show that the ill-posed domain is larger than what was found in previous analyses, not only comprising cases of bed degradation into a substrate finer than the active layer but also in aggradational cases. Furthermore, by analyzing a three-fraction model we observe ill-posedness under conditions of bed degradation into a coarse substrate. We observe that oscillations in the numerical solution of ill-posed simulations grow until the model becomes well-posed, as the spurious mixing of the active layer sediment and substrate sediment acts as a regularization mechanism. Finally we conduct an eigenstructure analysis of a simplified vertically continuous model for mixed sediment for which we show that ill-posedness occurs in a wider range of conditions than the active layer model.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.011
      Issue No: Vol. 114 (2018)
  • Global estimation of long-term persistence in annual river runoff
    • Authors: Y. Markonis; Y. Moustakis; C. Nasika; P. Sychova; P. Dimitriadis; M. Hanel; P. Máca; S.M. Papalexiou
      Pages: 1 - 12
      Abstract: Publication date: March 2018
      Source:Advances in Water Resources, Volume 113
      Author(s): Y. Markonis, Y. Moustakis, C. Nasika, P. Sychova, P. Dimitriadis, M. Hanel, P. Máca, S.M. Papalexiou
      Long-term persistence (LTP) of annual river runoff is a topic of ongoing hydrological research, due to its implications to water resources management. Here, we estimate its strength, measured by the Hurst coefficient H, in 696 annual, globally distributed, streamflow records with at least 80 years of data. We use three estimation methods (maximum likelihood estimator, Whittle estimator and least squares variance) resulting in similar mean values of H close to 0.65. Subsequently, we explore potential factors influencing H by two linear (Spearman's rank correlation, multiple linear regression) and two non-linear (self-organizing maps, random forests) techniques. Catchment area is found to be crucial for medium to larger watersheds, while climatic controls, such as aridity index, have higher impact to smaller ones. Our findings indicate that long-term persistence is weaker than found in other studies, suggesting that enhanced LTP is encountered in large-catchment rivers, were the effect of spatial aggregation is more intense. However, we also show that the estimated values of H can be reproduced by a short-term persistence stochastic model such as an auto-regressive AR(1) process. A direct consequence is that some of the most common methods for the estimation of H coefficient, might not be suitable for discriminating short- and long-term persistence even in long observational records.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.01.003
      Issue No: Vol. 113 (2018)
  • Emulsification kinetics during quasi-miscible flow in dead-end pores
    • Authors: M. Broens; E. Unsal
      Pages: 13 - 22
      Abstract: Publication date: March 2018
      Source:Advances in Water Resources, Volume 113
      Author(s): M. Broens, E. Unsal
      Microemulsions have found applications as carriers for the transport of solutes through various porous media. They are commonly pre-prepared in bulk form, and then injected into the medium. The preparation is done by actively mixing the surfactant, water and oil, and then allowing the mixture to stagnate until equilibrium is reached. The resulting microemulsion characteristics of the surfactant/oil/water system are studied at equilibrium conditions, and perfect mixing is assumed. But in applications like subsurface remediation and enhanced oil recovery, microemulsion formation may occur in the pore space. Surfactant solutions are injected into the ground to solubilize and/or mobilize the non-aqueous phase liquids (NAPLs) by in-situ emulsification. Flow dynamics and emulsification kinetics are coupled, which also contributes to in-situ mixing. In this study, we investigated the nature of such coupling for a quasi-miscible fluid system in a conductive channel with dead-end extensions. A microfluidic setup was used, where an aqueous solution of an anionic, internal olefin sulfonate 20–24 (IOS) surfactant was injected into n-decane saturated glass micromodel. The oil phase was coloured using a solvatochromatic dye allowing for direct visualization of the aqueous and oil phases as well as their microemulsions under fluorescent light. Presence of both conductive and stagnant dead-end channels in a single pore system made it possible to isolate different transport mechanisms from each other but also allowed to study the transitions from one to the other. In the conductive channel, the surfactant was carried with flow, and emulsification was controlled by the localized flow dynamics. In the stagnant zones, the driving force of the mass transfer was driven by the chemical concentration gradient. Some of the equilibrium phase behaviour characteristics of the surfactant/oil/water system were recognisable during the quasi-miscible displacement. However, the equilibrium tests alone were not sufficient to predict the emulsification process under dynamic conditions.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.01.001
      Issue No: Vol. 113 (2018)
           ROCK SURFACES
    • Authors: C.H. Gates; E. Perfect; B.S. Lokitz; J.W. Brabazon; L.D. McKay; J.S. Tyner
      Abstract: Publication date: Available online 7 April 2018
      Source:Advances in Water Resources
      Author(s): C.H. Gates, E. Perfect, B.S. Lokitz, J.W. Brabazon, L.D. McKay, J.S. Tyner
      Contact angle measurements for gas-liquid-rock systems are important for modeling multi-phase flow and transport in the subsurface. These data are needed in applications such as the extraction of oil and gas resources, geologic sequestration of carbon dioxide, contaminant fate and transport, and aquifer recharge through the vadose zone. Contact angles are frequently measured with the sessile drop method. Previous research has largely ignored the dynamic behavior of sessile droplets on geologic materials. This study investigates the dynamic behavior of sessile water droplets on prepared rock surfaces in the presence of air. Droplet diameter and advancing contact angle were determined at 0.5 s intervals for  ∼ 90 s on flat polished disks of Burlington limestone, Crossville sandstone, Mancos shale, Sierra White granite, Vermilion Bay granite, and Westerly granite using a Krüss DSA 30 Drop Shape Analyzer. The droplet diameter and advancing contact angle data sets were nonlinearly regressed against time using two different two-parameter models. The median coefficients of determination for the fits were 0.85 and 0.96, respectively. The resulting parameter estimates were used to compute the apparent equilibrium contact angle, θe , for each disk following droplet diameter stabilization. Estimates of θe ranged from 37.2° for Mancos shale to 75.6° for Burlington limestone. Analysis of variance indicated statistically significant differences in θe between the rock types at the 95% confidence level. The variability of θe on the polished rock surfaces was quantified by the coefficient of variation (CV) for θe , which varied between  ∼ 3 and  ∼ 9%; there were no significant differences in CV between the rock types. Neutron radiography indicated changes droplet morphology over time were due to the spontaneous imbibition of water into the rock matrix. The transient analysis employed in this study permits a more meaningful estimate of the equilibrium contact angle for rocks than taking the initial value or averaging over time as is frequently done.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.017
  • Hydro-Power Production and Fish Habitat Suitability: Assessing Impact and
           Effectiveness of Ecological Flows at Regional Scale
    • Authors: Serena Ceola; Alessio Pugliese; Matteo Ventura; Giorgio Galeati; Alberto Montanari; Attilio Castellarin
      Abstract: Publication date: Available online 5 April 2018
      Source:Advances in Water Resources
      Author(s): Serena Ceola, Alessio Pugliese, Matteo Ventura, Giorgio Galeati, Alberto Montanari, Attilio Castellarin
      Anthropogenic activities along streams and rivers may be of major concern for fluvial ecosystems, e.g. abstraction and impoundment of surface water resources may profoundly alter natural streamflow regimes. An established approach aimed at preserving the behavior and distribution of fluvial species relies on the definition of ecological flows (e-flows) downstream of dams and diversion structures. E-flow prescriptions are usually set by basin authorities at regional scale, often without a proper assessment of their impact and effectiveness. On the contrary, we argue that e-flows should be identified on the basis of (i) regional and (ii) quantitative assessments. We focus on central Italy and evaluate the effects on habitat suitability of two near-threatened fish species (i.e. Barbel and Chub) and an existing hydro-power network when shifting from the current time-invariant e-flow policy to a tighter and seasonally-varying soon-to-be-enforced one. Our example clearly shows that: (a) quantitative regional scale assessments are viable even when streamflow observations are entirely missing at study sites; (b) aprioristic e-flows policies may impose releases that exceed natural streamflows for significantly long time intervals (weeks, or months); (c) unduly tightening e-flow policies may heavily impact regional hydro-power productivity (15% and 42% losses on annual and seasonal basis, respectively), yet resulting in either marginal or negligible improvements of fluvial ecosystem.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.04.002
    • Authors: Nishank Saxena; Amie Hows; Ronny Hofmann; Faruk O. Alpak; Justin Freeman; Sander Hunter; Matthias Appel
      Abstract: Publication date: Available online 4 April 2018
      Source:Advances in Water Resources
      Author(s): Nishank Saxena, Amie Hows, Ronny Hofmann, Faruk O. Alpak, Justin Freeman, Sander Hunter, Matthias Appel
      This study defines the optimal operating envelope of the Digital Rock technology from the perspective of imaging and numerical simulations of transport properties. Imaging larger volumes of rocks for Digital Rock Physics (DRP) analysis improves the chances of achieving a Representative Elementary Volume (REV) at which flow-based simulations (1) do not vary with change in rock volume, and (2) is insensitive to the choice of boundary conditions. However, this often comes at the expense of image resolution. This trade-off exists due to the finiteness of current state-of-the-art imaging detectors. Imaging and analyzing digital rocks that sample the REV and still sufficiently resolve pore throats is critical to ensure simulation quality and robustness of rock property trends for further analysis. We find that at least 10 voxels are needed to sufficiently resolve pore throats for single phase fluid flow simulations. If this condition is not met, additional analyses and corrections may allow for meaningful comparisons between simulation results and laboratory measurements of permeability, but some cases may fall outside the current technical feasibility of DRP. On the other hand, we find that the ratio of field of view and effective grain size provides a reliable measure of the REV for siliciclastic rocks. If this ratio is greater than 5, the coefficient of variation for single-phase permeability simulations drops below 15 %. These imaging considerations are crucial when comparing digitally computed rock flow properties with those measured in the laboratory. We find that the current imaging methods are sufficient to achieve both REV (with respect to numerical boundary conditions) and required image resolution to perform digital core analysis for coarse to fine-grained sandstones.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.04.001
  • A Numerical Study of the Complex Flow Structure in a Compound Meandering
    • Authors: Ignacio J. Moncho-Esteve; Guillermo Palau-Salvador; Manuel García-Villalba; Yasu Muto; Koji Shiono
      Abstract: Publication date: Available online 21 March 2018
      Source:Advances in Water Resources
      Author(s): Ignacio J. Moncho-Esteve, Guillermo Palau-Salvador, Manuel García-Villalba, Yasu Muto, Koji Shiono
      In this study, we report large eddy simulations of turbulent flow in a periodic compound meandering channel for three different depth conditions: one in-bank and two overbank conditions. The flow configuration corresponds to the experiments of Shiono and Muto (1998). The predicted mean streamwise velocities, mean secondary motions, velocity fluctuations, turbulent kinetic energy as well as mean flood flow angle to meandering channel are in good agreement with the experimental measurements. We have analyzed the flow structure as a function of the inundation level, with particular emphasis on the development of the secondary motions due to the interaction between the main channel and the floodplain flow. Bed shear stresses have been also estimated in the simulations. Floodplain flow has a significant impact on the flow structure leading to significantly different bed shear stress patterns within the main meandering channel. The implications of these results for natural compound meandering channels are also discussed.

      PubDate: 2018-04-11T01:51:15Z
      DOI: 10.1016/j.advwatres.2018.03.013
  • An Improved Method for Estimating Capillary Pressure from 3D
           Microtomography Images and its Application to the Study of Disconnected
           Nonwetting Phase
    • Authors: Tianyi Li; Steffen Schlüter; Maria Ines Dragila; Dorthe Wildenschild
      Abstract: Publication date: Available online 21 February 2018
      Source:Advances in Water Resources
      Author(s): Tianyi Li, Steffen Schlüter, Maria Ines Dragila, Dorthe Wildenschild
      We present an improved method for estimating interfacial curvatures from x-ray computed microtomography (CMT) data that significantly advances the potential for this tool to unravel the mechanisms and phenomena associated with multi-phase fluid motion in porous media. CMT data, used to analyze the spatial distribution and pressure-saturation (P-S) relationships of liquid phases, requires accurate estimates of interfacial curvature. Our improved method for curvature estimation combines selective interface modification and distance weighting approaches. It was verified against synthetic (analytical computer-generated) and real image data sets, demonstrating a vast improvement over previous methods. Using this new tool on a previously published data set (multiphase flow) yielded important new insights regarding the pressure state of the disconnected nonwetting phase during drainage and imbibition. The trapped and disconnected non-wetting phase delimits its own hysteretic P-S curve that inhabits the space within the main hysteretic P-S loop of the connected wetting phase. Data suggests that the pressure of the disconnected, non-wetting phase is strongly modified by the pore geometry rather than solely by the bulk liquid phase that surrounds it.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.012
  • Modeling the Poroelastic Response to Megathrust Earthquakes: A look at the
           2012 Mw 7.6 Costa Rican Event
    • Authors: Kimberly A. McCormack; Marc A. Hesse
      Abstract: Publication date: Available online 21 February 2018
      Source:Advances in Water Resources
      Author(s): Kimberly A. McCormack, Marc A. Hesse
      We model the subsurface hydrologic response to the 7.6 Mw subduction zone earthquake that occurred on the plate interface beneath the Nicoya peninsula in Costa Rica on September 5, 2012. The regional-scale poroelastic model of the overlying plate integrates seismologic, geodetic and hydrologic data sets to predict the post-seismic poroelastic response. A representative two-dimensional model shows that thrust earthquakes with a slip width less than a third of their depth produce complex multi-lobed pressure perturbations in the shallow subsurface. This leads to multiple poroelastic relaxation timescales that may overlap with the longer viscoelastic timescales. In the three-dimensional model, the complex slip distribution of 2012 Nicoya event and its small width to depth ratio lead to a pore pressure distribution comprising multiple trench parallel ridges of high and low pressure. This leads to complex groundwater flow patterns, non-monotonic variations in predicted well water levels, and poroelastic relaxation on multiple time scales. The model also predicts significant tectonically driven submarine groundwater discharge off-shore. In the weeks following the earthquake, the predicted net submarine groundwater discharge in the study area increases, creating a 100 fold increase in net discharge relative to topography-driven flow over the first 30 days. Our model suggests the hydrological response on land is more complex than typically acknowledged in tectonic studies. This may complicate the interpretation of transient post-seismic surface deformations. Combined tectonic-hydrological observation networks have the potential to reduce such ambiguities.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.014
  • Unified theory for stochastic modelling of hydroclimatic processes:
           Preserving marginal distributions, correlation structures, and
    • Authors: Simon Michael Papalexiou
      Abstract: Publication date: Available online 15 February 2018
      Source:Advances in Water Resources
      Author(s): Simon Michael Papalexiou
      Hydroclimatic processes come in all “shapes and sizes”. They are characterized by different spatiotemporal correlation structures and probability distributions that can be continuous, mixed-type, discrete or even binary. Simulating such processes by reproducing precisely their marginal distribution and linear correlation structure, including features like intermittency, can greatly improve hydrological analysis and design. Traditionally, modelling schemes are case specific and typically attempt to preserve few statistical moments providing inadequate and potentially risky distribution approximations. Here, a single framework is proposed that unifies, extends, and improves a general-purpose modelling strategy, based on the assumption that any process can emerge by transforming a specific “parent” Gaussian process. A novel mathematical representation of this scheme, introducing parametric correlation transformation functions, enables straightforward estimation of the parent-Gaussian process yielding the target process after the marginal back transformation, while it provides a general description that supersedes previous specific parameterizations, offering a simple, fast and efficient simulation procedure for every stationary process at any spatiotemporal scale. This framework, also applicable for cyclostationary and multivariate modelling, is augmented with flexible parametric correlation structures that parsimoniously describe observed correlations. Real-world simulations of various hydroclimatic processes with different correlation structures and marginals, such as precipitation, river discharge, wind speed, humidity, extreme events per year, etc., as well as a multivariate example, highlight the flexibility, advantages, and complete generality of the method.

      PubDate: 2018-02-25T19:30:05Z
      DOI: 10.1016/j.advwatres.2018.02.013
  • Comparative analysis of the apparent saturation hysteresis approach and
           the domain theory of hysteresis in respect of prediction of scanning
           curves and air entrapment
    • Authors: A. Beriozkin; Y. Mualem
      Abstract: Publication date: Available online 3 February 2018
      Source:Advances in Water Resources
      Author(s): A. Beriozkin, Y. Mualem
      This study theoretically analyzes the concept of apparent saturation hysteresis, combined with the Scott et al. (1983) scaling approach, as suggested by Parker & Lenhard (1987), to account for the effect of air entrapment and release on the soil water hysteresis. We found that the theory of Parker & Lenhard (1987) is comprised of some mutually canceling mathematical operations, and when cleared of the superfluous intermediate calculations, their model reduces to the original Scott et al.’s (1983) scaling method, supplemented with the requirement of closure of scanning loops. Our analysis reveals that actually there is no effect of their technique of accounting for the entrapped air on the final prediction of the effective saturation (or water content) scanning curves. Our consideration indicates that the use of the Land (1968) formula for assessing the amount of entrapped air is in disaccord with the apparent saturation concept as introduced by Parker & Lenhard (1987). In this paper, a proper routine is suggested for predicting hysteretic scanning curves of any order, given the two measured main curves, in the complete hysteretic domain and some verification tests are carried out versus measured results. Accordingly, explicit closed-form formulae for direct prediction (with no need of intermediate calculation) of scanning curves up to the third order are derived to sustain our analysis.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.01.016
  • Review:Large eddy simulations of sediment entrainment induced by a
           lock-exchange gravity current
    • Authors: Foteini Kyrousi; A. Leonardi; F. Roman; V. Armenio; F. Zanello; J. Zordan; C. Juez; L. Falcomer
      Abstract: Publication date: Available online 2 February 2018
      Source:Advances in Water Resources
      Author(s): Foteini Kyrousi, A. Leonardi, F. Roman, V. Armenio, F. Zanello, J. Zordan, C. Juez, L. Falcomer
      Large Eddy simulations of lock-exchange gravity currents propagating over a mobile reach are presented. The numerical setting allows to investigate the sediment pick up induced by the currents and to study the underlying mechanisms leading to sediment entrainment for different Grashof numbers and grain sizes. First, the velocity field and the bed shear-stress distribution are investigated, along with turbulent structures formed in the flow, before the current reaches the mobile bed. Then, during the propagation of the current above the erodible section of the bed the contour plots of the entrained material are presented as well as the time evolution of the areas covered by the current and by the sediment at this section. The numerical outcomes are compared with experimental data showing a very good agreement. Overall, the study confirms that sediment pick up is prevalent at the head of the current where the strongest turbulence occurs. Further, above the mobile reach of the bed, settling process seems to be of minor importance, with the entrained material being advected downstream by the current. Additionally, the study shows that, although shear stress is the main mechanism that sets particles in motion, turbulent bursts as well as vertical velocity fluctuations are also necessary to counteract the falling velocity of the particles and maintain them into suspension. Finally, the analysis of the stability conditions of the current shows that, from one side, sediment concentration gives a negligible contribution to the stability of the front of the current and from the other side, the stability conditions provided by the current do not allow sediments to move into the ambient fluid.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.02.002
  • The solution of the dam-break problem in the Porous Shallow water
    • Authors: Luca Cozzolino; Veronica Pepe; Luigi Cimorelli; Andrea D'Aniello; Renata Della Morte; Domenico Pianese
      Abstract: Publication date: Available online 2 February 2018
      Source:Advances in Water Resources
      Author(s): Luca Cozzolino, Veronica Pepe, Luigi Cimorelli, Andrea D'Aniello, Renata Della Morte, Domenico Pianese
      The Porous Shallow water Equations are commonly used to evaluate the propagation of flooding waves in the urban environment. These equations may exhibit not only classic shocks, rarefactions, and contact discontinuities, as in the ordinary two-dimensional Shallow water Equations, but also special discontinuities at abrupt porosity jumps. In this paper, an appropriate parameterization of the stationary weak solutions of one-dimensional Porous Shallow water Equations supplies the inner structure of the porosity jumps. The exact solution of the corresponding dam-break problem is presented, and six different wave configurations are individuated, proving that the solution exists and it is unique for given initial conditions and geometric characteristics. These results can be used as a benchmark in order to validate one- and two-dimensional numerical models for the solution of the Porous Shallow water Equations. In addition, it is presented a novel Finite Volume scheme where the porosity jumps are taken into account by means of a variables reconstruction approach. The dam-break results supplied by this numerical scheme are compared with the exact dam-break results, showing the promising capabilities of this numerical approach. Finally, the advantages of the novel porosity jump definition are shown by comparison with other definitions available in the literature, demonstrating its advantages, and the issues raising in real world applications are discussed.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.01.026
  • Pilot Points Method for Conditioning Multiple-Point Statistical Facies
           Simulation on Flow Data
    • Authors: Wei Ma; Behnam Jafarpour
      Abstract: Publication date: Available online 2 February 2018
      Source:Advances in Water Resources
      Author(s): Wei Ma, Behnam Jafarpour
      We propose a new pilot points method for conditioning discrete multiple-point statistical (MPS) facies simulation on dynamic flow data. While conditioning MPS simulation on static hard data is straightforward, their calibration against nonlinear flow data is nontrivial. The proposed method generates conditional models from a conceptual model of geologic connectivity, known as a training image (TI), by strategically placing and estimating pilot points. To place pilot points, a score map is generated based on three sources of information: (i) the uncertainty in facies distribution, (ii) the model response sensitivity information, and (iii) the observed flow data. Once the pilot points are placed, the facies values at these points are inferred from production data and then are used, along with available hard data at well locations, to simulate a new set of conditional facies realizations. While facies estimation at the pilot points can be performed using different inversion algorithms, in this study the ensemble smoother (ES) is adopted to update permeability maps from production data, which are then used to statistically infer facies types at the pilot point locations. The developed method combines the information in the flow data and the TI by using the former to infer facies values at selected locations away from the wells and the latter to ensure consistent facies structure and connectivity where away from measurement locations. Several numerical experiments are used to evaluate the performance of the developed method and to discuss its important properties.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.01.021
  • Simulation of dynamic expansion, contraction, and connectivity in a
           mountain stream network
    • Authors: Adam S. Ward; Noah M. Schmadel; Steven M. Wondzell
      Abstract: Publication date: Available online 31 January 2018
      Source:Advances in Water Resources
      Author(s): Adam S. Ward, Noah M. Schmadel, Steven M. Wondzell
      Headwater stream networks expand and contract in response to changes in stream discharge. The changes in the extent of the stream network are also controlled by geologic or geomorphic setting – some reaches go dry even under relatively wet conditions, other reaches remain flowing under relatively dry conditions. While such patterns are well recognized, we currently lack tools to predict the extent of the stream network and the times and locations where the network is dry within large river networks. Here, we develop a perceptual model of the river corridor in a headwater mountainous catchment, translate this into a reduced-complexity mechanistic model, and implement the model to examine connectivity and network extent over an entire water year. Our model agreed reasonably well with our observations, showing that the extent and connectivity of the river network was most sensitive to hydrologic forcing under the lowest discharges (Qgauge < 1 L s−1), that at intermediate discharges (1 L s−1 < Qgauge < 1 L s−1) the extent of the network changed dramatically with changes in discharge, and that under wet conditions (Qgauge > 1 L s−1) the extent of the network was relatively insensitive to hydrologic forcing and was instead determined by the network topology. We do not expect that the specific thresholds observed in this study would be transferable to other catchments with different geology, topology, or hydrologic forcing. However, we expect that the general pattern should be robust: the dominant controls will shift from hydrologic forcing to geologic setting as discharge increases.. Further, our method is readily transferable as the model can be applied with minimal data requirements (a single stream gauge, a digital terrain model, and estimates of hydrogeologic properties) to estimate flow duration or connectivity along the river corridor in unstudied catchments. As the available information increases, the model could be better calibrated to match site-specific observations of network extent, locations of dry reaches, or solute break through curves as demonstrated in this study. Based on the low initial data requirements and ability to later tune the model to a specific site, we suggest example applications of this parsimonious model that may prove useful to both researchers and managers.

      PubDate: 2018-02-05T16:57:57Z
      DOI: 10.1016/j.advwatres.2018.01.018
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