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  • 1. Addor, Nans
    et al.
    Rössler, Ole
    Köplin, Nina
    Huss, Matthias
    Weingartner, Rolf
    Seibert, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Robust changes and sources of uncertainty in the projected hydrological regimes of Swiss catchments2014Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 50, nr 10, s. 7541-7562Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Projections of discharge are key for future water resources management. These projections are subject to uncertainties, which are difficult to handle in the decision process on adaptation strategies. Uncertainties arise from different sources such as the emission scenarios, the climate models and their postprocessing, the hydrological models, and the natural variability. Here we present a detailed and quantitative uncertainty assessment, based on recent climate scenarios for Switzerland (CH2011 data set) and covering catchments representative for midlatitude alpine areas. This study relies on a particularly wide range of discharge projections resulting from the factorial combination of 3 emission scenarios, 10–20 regional climate models, 2 postprocessing methods, and 3 hydrological models of different complexity. This enabled us to decompose the uncertainty in the ensemble of projections using analyses of variance (ANOVA). We applied the same modeling setup to six catchments to assess the influence of catchment characteristics on the projected streamflow, and focused on changes in the annual discharge cycle. The uncertainties captured by our setup originate mainly from the climate models and natural climate variability, but the choice of emission scenario plays a large role by the end of the 21st century. The contribution of the hydrological models to the projection uncertainty varied strongly with catchment elevation. The discharge changes were compared to the estimated natural decadal variability, which revealed that a climate change signal emerges even under the lowest emission scenario (RCP2.6) by the end of the century. Limiting emissions to RCP2.6 levels would nevertheless reduce the largest regime changes by the end of the century by approximately a factor of two, in comparison to impacts projected for the high emission scenario SRES A2. We finally show that robust regime changes emerge despite the projection uncertainty. These changes are significant and are consistent across a wide range of scenarios and catchments. We propose their identification as a way to aid decision making under uncertainty.

  • 2. Ahlers, R.
    et al.
    Cleaver, F
    Rusca, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Schwartz, K.
    Unleashing Entrepreneurs or Controlling Unruly Providers?: The Formalisation of Small-scale Water Providers in Greater Maputo, Mozambique2013Ingår i: Journal of Development Studies, ISSN 0022-0388, E-ISSN 1743-9140, Vol. 49, nr 4, s. 470-482Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The existing legal and policy framework regulating water service provision in Greater Maputo, Mozambique appears fixated on the official service areas. In doing so it inadequately addresses the geographically varied service provision modalities which characterise the city. We argue that the predominant legal and policy framework does little to support development of improved services in areas unserved by the formal utility. Although ad hoc measures recognising small-scale providers as a temporary alternative to service provision by a formal utility have been implemented, these measures appear designed to increase control over these providers rather than support the service delivery capacity of small-scale providers.

  • 3. Alda-Vidal, C.
    et al.
    Kooy, M.
    Rusca, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Mapping operation and maintenance: an everyday urbanism analysis of inequalities within piped water supply in Lilongwe, Malawi2018Ingår i: Urban Geography, Vol. 39, nr 1, s. 104-121Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this article, we analyze the production of inequalities within the centralized water supply network of Lilongwe. We use a process-based analysis to understand how urban infrastructure is made to work and explain the disparity in levels of service by tracing the everyday practices of those who operate the infrastructure. This extends existing analyses of everyday practices in relation to urban water inequalities in African cities by focusing on formal operators, rather than water users, and looking within the networked system, rather than outside it. Our findings show that these practices work to exacerbate existing water stress in poor areas of the city. We conclude with a reflection on how understanding these practices as the product of the perceptions, rationalizations, and interpretations of utility staff who seek to manage the city’s (limited) water as best they can offers insight into what is required for a more progressive urban water politics.

  • 4. Alda-Vidal, C.
    et al.
    Rusca, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Zwarteveen, M.
    Schwartz, K.
    Pouw, N.
    Occupational genders and gendered occupations: the case of water provisioning in Maputo, Mozambique2017Ingår i: Gender, Place and Culture: A Journal of Feminist Geography, ISSN 0966-369X, E-ISSN 1360-0524, Vol. 24, nr 7, s. 974-990Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Taking issue with how associations between technical prowess or entrepreneurship and masculinity tend to be taken for granted or are seen as stemming from natural or intrinsic gender differences, over the last two decades feminist scholars have developed theoretical approaches to understand the gendering of professions and abilities as the performative outcome of particular cultures and histories. We build on these insights to explore how associations between masculinities, technology and entrepreneurship shape ideas and practices of small-scale water provision in Maputo. Our findings show how activities (i.e. technical craftsmanship, hard physical work) or abilities (i.e. risk-taking, innovativeness) regarded as masculine tend to be considered the defining features of the profession. This shapes how men and women make sense of and talk about their work, each of them tactically emphasizing and performing those aspects best fitting their gender. Our detailed documentation of men’s and women’s everyday involvements in water provisioning challenges the existence of sharp boundaries and distinctions between genders and professional responsibilities. It shows that water provisioning requires many other types of work and skills and male and female household members collaborate and share their work. The strong normative-cultural associations between gender and water provisioning lead to a distinct under-recognition of women’s importance as water providers. We conclude that strategies to effectively support small-scale water businesses while creating more space and power for women involved in the business require the explicit recognition and re-conceptualization of water provisioning as a household business.

  • 5.
    Alfieri, Lorenzo
    et al.
    European Commiss Joint Res Ctr, TP 122,Via E Fermi 2749, I-21027 Ispra, VA, Italy.
    Feyen, Luc
    European Commiss Joint Res Ctr, TP 122,Via E Fermi 2749, I-21027 Ispra, VA, Italy.
    Di Baldassarre, Giuliano
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Increasing flood risk under climate change: a pan-European assessment of the benefits of four adaptation strategies2016Ingår i: Climatic Change, Vol. 136, nr 3, s. 507-521Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Future flood risk in Europe is likely to increase due to a combination of climatic and socio-economic drivers. Effective adaptation strategies need to be implemented to limit the impact of river flooding on population and assets. This research builds upon a recently developed flood risk assessment framework at European scale to explore the benefits of adaptation against extreme floods. The effect of implementing four different adaptation measures is simulated in the modeling framework. Measures include the rise of flood protections, reduction of the peak flows through water retention, reduction of vulnerability and relocation to safer areas. Their sensitivity is assessed in several configurations under a high-end global warming scenario over the time range 1976-2100. Results suggest that the future increase in expected damage and population affected by river floods can be compensated through different configurations of adaptation measures. The adaptation efforts should favor measures targeted at reducing the impacts of floods, rather than trying to avoid them. Conversely, adaptation plans only based on rising flood protections have the effect of reducing the frequency of small floods and exposing the society to less-frequent but catastrophic floods and potentially long recovery processes.

  • 6.
    Alfonso, L.
    et al.
    UNESCO IHE Inst Water Educ, Integrated Water Syst & Governance, Delft, Netherlands..
    Mukolwe, M. M.
    UNESCO IHE Inst Water Educ, Integrated Water Syst & Governance, Delft, Netherlands.;Masinde Muliro Univ Sci & Technol, Estates Dept, Kakamega, Kenya..
    Di Baldassarre, Giuliano
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Probabilistic Flood Maps to support decision-making: Mapping the Value of Information2016Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 52, nr 2, s. 1026-1043Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Floods are one of the most frequent and disruptive natural hazards that affect man. Annually, significant flood damage is documented worldwide. Flood mapping is a common preimpact flood hazard mitigation measure, for which advanced methods and tools (such as flood inundation models) are used to estimate potential flood extent maps that are used in spatial planning. However, these tools are affected, largely to an unknown degree, by both epistemic and aleatory uncertainty. Over the past few years, advances in uncertainty analysis with respect to flood inundation modeling show that it is appropriate to adopt Probabilistic Flood Maps (PFM) to account for uncertainty. However, the following question arises; how can probabilistic flood hazard information be incorporated into spatial planning? Thus, a consistent framework to incorporate PFMs into the decision-making is required. In this paper, a novel methodology based on Decision-Making under Uncertainty theories, in particular Value of Information (VOI) is proposed. Specifically, the methodology entails the use of a PFM to generate a VOI map, which highlights floodplain locations where additional information is valuable with respect to available floodplain management actions and their potential consequences. The methodology is illustrated with a simplified example and also applied to a real case study in the South of France, where a VOI map is analyzed on the basis of historical land use change decisions over a period of 26 years. Results show that uncertain flood hazard information encapsulated in PFMs can aid decision-making in floodplain planning.

  • 7. Ali, A Md
    et al.
    Di Baldassarre, G
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Solomatine, Dimitri P
    Testing different cross-section spacing in 1D hydraulic modelling: A case study on Johor River, Malaysia2014Ingår i: Hydrological Sciences Journal, nr just-acceptedArtikel i tidskrift (Refereegranskat)
  • 8. Ali, Genevieve
    et al.
    Tetzlaff, Doerthe
    McDonnell, Jeffrey J.
    Soulsby, Chris
    Carey, Sean
    Laudon, Hjalmar
    McGuire, Kevin
    Buttle, Jim
    Seibert, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Shanley, Jamie
    Comparison of threshold hydrologic response across northern catchments2015Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, nr 16, s. 3575-3591Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nine mid-latitude to high-latitude headwater catchments - part of the Northern Watershed Ecosystem Response to Climate Change (North-Watch) programme - were used to analyze threshold response to rainfall and snowmelt-driven events and link the different responses to the catchment characteristics of the nine sites. The North-Watch data include daily time-series of various lengths of multiple variables such as air temperature, precipitation and discharge. Rainfall and meltwater inputs were differentiated using a degree-day snowmelt approach. Distinct hydrological events were identified, and precipitation-runoff response curves were visually assessed. Results showed that eight of nine catchments showed runoff initiation thresholds and effective precipitation input thresholds. For rainfall-triggered events, catchment hydroclimatic and physical characteristics (e.g. mean annual air temperature, median flow path distance to the stream, median sub-catchment area) were strong predictors of threshold strength. For snowmelt-driven events, however, thresholds and the factors controlling precipitation-runoff response were difficult to identify. The variability in catchments responses to snowmelt was not fully explained by runoff initiation thresholds and input magnitude thresholds. The quantification of input intensity thresholds (e.g. snow melting and permafrost thawing rates) is likely required for an adequate characterization of nonlinear spring runoff generation in such northern environments.

  • 9.
    Ameli, A. A.
    et al.
    Univ Western Ontario, Dept Biol, Biol & Geol Sci Bldg, London, ON N6A 3K7, Canada.;Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Uppsala Univ, Dept Earth Sci Air Water & Landscape Sci, Uppsala, Sweden..
    McDonnell, J. J.
    Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Univ Aberdeen, Sch Geosci, Aberdeen, Scotland..
    Bishop, Kevin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Uppsala centrum för hållbar utveckling, CSD Uppsala. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Swedish Univ Agr Sci SLU, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    The exponential decline in saturated hydraulic conductivity with depth: a novel method for exploring its effect on water flow paths and transit time distribution2016Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 30, nr 14, s. 2438-2450Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The strong vertical gradient in soil and subsoil saturated hydraulic conductivity is characteristic feature of the hydrology of catchments. Despite the potential importance of these strong gradients, they have proven difficult to model using robust physically based schemes. This has hampered the testing of hypotheses about the implications of such vertical gradients for subsurface flow paths, residence times and transit time distribution. Here we present a general semi-analytical solution for the simulation of 2D steady-state saturated-unsaturated flow in hillslopes with saturated hydraulic conductivity that declines exponentially with depth. The grid-free solution satisfies mass balance exactly over the entire saturated and unsaturated zones. The new method provides continuous solutions for head, flow and velocity in both saturated and unsaturated zones without any interpolation process as is common in discrete numerical schemes. This solution efficiently generates flow pathlines and transit time distributions in hillslopes with the assumption of depth-varying saturated hydraulic conductivity. The model outputs reveal the pronounced effect that changing the strength of the exponential decline in saturated hydraulic conductivity has on the flow pathlines, residence time and transit time distribution. This new steady-state model may be useful to others for posing hypotheses about how different depth functions for hydraulic conductivity influence catchment hydrological response.

  • 10. Ameli, A.A.
    et al.
    Amvrosiadi, Nino
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Grabs, Thomas
    Laudon, Hjalmar
    Creed, I.F.
    McDonnell, J.J.
    Bishop, Kevin
    Hillslope permeability architecture controls on subsurface transit time distribution and flow paths2016Ingår i: Journal of Hydrology, Vol. 543, s. 17-30Artikel i tidskrift (Refereegranskat)
  • 11.
    Ameli, Ali A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Western Univ, Dept Biol, London, ON, Canada..
    Controls on subsurface transport of sorbing contaminant2017Ingår i: Hydrology Research, ISSN 1998-9563, E-ISSN 2224-7955, Vol. 48, nr 5, s. 1226-1239Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Subsurface transport of a sorbing contaminant is poorly understood and characterized. Here, a new semi-analytical saturated-unsaturated flow and transport model is coupled to a kinetic sorption algorithm to assess the impact of changes in the subsurface permeability architecture and flow rate on sorption characteristics. The model outputs reveal the pronounced effect of the rate of vertical decline in K-s on the frequency of occurrence and spatial distribution of subsurface sorption as well as the timing and rate of sorbing contaminants discharged into stream. Sorption potential is weakened with infiltration rate. The impact of infiltration rate on the decline in sorption potential becomes more accentuated as the degree of subsurface vertical heterogeneity in saturated hydraulic conductivity increases. Porosity pattern also impacts sorption characteristics; but its effects highly depend upon the degree of vertical heterogeneity in Ks. The results and methodology presented in this paper have potential implications for assessing water quality in integrated groundwater-surface water systems as well as designing remediation systems.

  • 12.
    Ameli, Ali A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Western Univ, Dept Biol, London, ON, Canada.
    Beven, Keith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Lancaster, Lancaster Environm Ctr, Lancaster, England..
    Erlandsson, Martin
    Stockholm Univ, Dept Phys Geog, Stockholm, Sweden..
    Creed, Irena F.
    Western Univ, Dept Biol, London, ON, Canada..
    McDonnell, Jeffrey J.
    Univ Saskatchewan, Global Inst Water Secur, Saskatoon, SK, Canada.;Univ Aberdeen, Sch Geosci, Aberdeen, Scotland.;Oregon State Univ, Dept Forest Engn Resources & Management, Corvallis, OR 97331 USA..
    Bishop, Kevin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden..
    Primary weathering rates, water transit times, and concentration-discharge relations: A theoretical analysis for the critical zone2017Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 53, nr 1, s. 942-960Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The permeability architecture of the critical zone exerts a major influence on the hydrogeochemistry of the critical zone. Water flow path dynamics drive the spatiotemporal pattern of geochemical evolution and resulting streamflow concentration-discharge (C-Q) relation, but these flow paths are complex and difficult to map quantitatively. Here we couple a new integrated flow and particle tracking transport model with a general reversible Transition State Theory style dissolution rate law to explore theoretically how C-Q relations and concentration in the critical zone respond to decline in saturated hydraulic conductivity (K-s) with soil depth. We do this for a range of flow rates and mineral reaction kinetics. Our results show that for minerals with a high ratio of equilibrium concentration ( Ceq) to intrinsic weathering rate ( Rmax), vertical heterogeneity in K-s enhances the gradient of weathering-derived solute concentration in the critical zone and strengthens the inverse stream C-Q relation. As <mml:mfrac>CeqRmax</mml:mfrac> decreases, the spatial distribution of concentration in the critical zone becomes more uniform for a wide range of flow rates, and stream C-Q relation approaches chemostatic behavior, regardless of the degree of vertical heterogeneity in K-s. These findings suggest that the transport-controlled mechanisms in the hillslope can lead to chemostatic C-Q relations in the stream while the hillslope surface reaction-controlled mechanisms are associated with an inverse stream C-Q relation. In addition, as <mml:mfrac>CeqRmax</mml:mfrac> decreases, the concentration in the critical zone and stream become less dependent on groundwater age (or transit time).

  • 13.
    Amland, Sølvi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Hvor er de markene i Sverige som er mest sensitive ovenfor forsuring og nitrogentap?2012Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Several factors affect whether the ground is prone to acidification and nitrogen loss. Removal of biological materials is an important factor that can trigger this. In Sweden, three dominant forest tree species are spruce, pine and birch trees. For forestry purposes, these trees are being logged at their potimal harvesting ages which are averaged at 70 years of age. This is of interest beacuse the forest ages can be used to predict future forestry practices, specifically in Dalarna, Sweden. The forest ages were observed at a catchment based level so that the effects of forestry can easily be measured. It was found that cathcments in the north of Dalarna consist of higher percentages of forest over the age of 70 in comparsion to the south and areas surrounding lakes. From this, it is expected that forestry will occur in the near future in the north.

    Hopefully the work that has been done in Dalarna, can be used as a model for the rest of Sweden.

  • 14.
    Amvrosiadi, Nino
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Temporal Dynamics of Total Organic Carbon Export Rates in Swedish Streams: Importance of discharge conditions and seasonal effects2012Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The amount of total organic carbon (TOC) in water is a rough indicator of the waterquality. Driven by the question how the TOC concentration would vary acrossstreams in Sweden under different climate conditions (e.g. more extreme dischargeevents), the temporal dynamics of TOC were examined for different stream subgroupswith six orders of magnitude catchment area span. In addition, the relationshipbetween dissolved inorganic carbon (DIC) export (both downstream and evasion) anddischarge conditions was also studied. Another question addressed was if the amountof TOC exported can be affected by export conditions dominating the previousseason. TOC export followed closely the discharge, which is in agreement withprevious studies, and all 42 catchments studied across Sweden were described by thispositive relationship regardless their size. A linear TOC export response to dischargewas identified during extreme discharge conditions. Furthermore, the TOC export wassignificantly related to the antecedent TOC export conditions for approximately halfof the 18 studied catchments with areas ranging between 2.5·10-3 and 67 km2.

  • 15.
    Amvrosiadi, Nino
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    The value of experimental data and modelling for exploration of hydrological functioning: The case of a till hillslope2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Successfully modeling one system response (e.g. hydrograph or solute transport) sometimes gives the false sense of well-characterizing the modeled system. This is partly because of the well-known equifinality issue; during the calibration process multiple parameter combinations can produce similarly good results. One step forward towards a better-defined system is using measured (at relevant scale) values for the model parameters, as well as using multiple conditions to constrain the model.

    But when not enough, or relevant, field measurements are available, virtual experiments (VE’s) can be used as a supplementary method to model calibration. The advantage of VE’s over model calibration is that they can also be used to explore assumptions both on the system hydrological processes, and on the model structure.

    One goal of this study was to utilize both field measurements and models for better characterization of the S-transect hillslope, located in Västrabäcken catchment, Northern Sweden. This included (a) characteristics in space: system vertical boundaries, hydraulic parameters, pore water velocity distribution, spatial correlation of flowpaths, soil water retention properties; (b) characteristic of system’s dynamic behavior: storage – discharge relationship, transit time distribution, turnover time; and (c) outputs’ sensitivity to external forcing, and to small scale structure assumptions. The second goal was to comment on the value of field measurements and virtual experiments for extracting information about the studied system.

    An intensely monitored study hillslope was chosen for this work. Although the hillslope has already been the subject of multiple field and modelling studies, there are still open questions regarding the characteristics listed above. The models used were the Vertical Equilibrium Model (VEM), and the Multiple Interacting Pathways (MIPs) model.

    It was found that the hillslope was well connected; from the near-stream areas up to the water divide the storage – discharge relationship could be described as an exponential function. Also, the dynamic storage (which controls the hydrograph dynamics) was much smaller comparing to the total hillslope storage. The unsaturated soil storage was found to be more sensitive to water table positions than vertical flux magnitude. The dynamic condition of external forcing (precipitation and evapotranspiration) affected the transit time distribution (TTD) shape. And, opposite to expectations, TTD was not sensitive to micro-scale structural assumptions tested here.

    Delarbeten
    1. Water storage dynamics in a till hillslope: the foundation for modeling flows and turnover times
    Öppna denna publikation i ny flik eller fönster >>Water storage dynamics in a till hillslope: the foundation for modeling flows and turnover times
    2017 (Engelska)Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 31, nr 1, s. 4-14Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Studies on hydrology, biogeochemistry, or mineral weathering often rely on assumptions about flow paths, water storage dynamics, and transit times. Testing these assumptions requires detailed hydrometric data that are usually unavailable at the catchment scale. Hillslope studies provide an alternative for obtaining a better understanding, but even on such well‐defined and delimited scales, it is rare to have a comprehensive set of hydrometric observations from the water divide down to the stream that can constrain efforts to quantify water storage, movement, and turnover time. Here, we quantified water storage with daily resolution in a hillslope during the course of almost an entire year using hydrological measurements at the study site and an extended version of the vertical equilibrium model. We used an exponential function to simulate the relationship between hillslope discharge and water table; this was used to derive transmissivity profiles along the hillslope and map mean pore water velocities in the saturated zone. Based on the transmissivity profiles, the soil layer transmitting 99% of lateral flow to the stream had a depth that ranged from 8.9 m at the water divide to under 1 m closer to the stream. During the study period, the total storage of this layer varied from 1189 to 1485 mm, resulting in a turnover time of 2172 days. From the pore water velocities, we mapped the time it would take a water particle situated at any point of the saturated zone anywhere along the hillslope to exit as runoff. Our calculations point to the strengths as well as limitations of simple hydrometric data for inferring hydrological properties and water travel times in the subsurface.

    Nyckelord
    flow pathways, storage, storage dynamics, turnover time
    Nationell ämneskategori
    Geovetenskap och miljövetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-331679 (URN)10.1002/hyp.11046 (DOI)000441296100001 ()
    Tillgänglig från: 2017-10-16 Skapad: 2017-10-16 Senast uppdaterad: 2018-10-12Bibliografiskt granskad
    2. Soil moisture storage estimation based on steady vertical fluxes under equilibrium
    Öppna denna publikation i ny flik eller fönster >>Soil moisture storage estimation based on steady vertical fluxes under equilibrium
    2017 (Engelska)Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 553, s. 798-804Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Soil moisture is an important variable for hillslope and catchment hydrology. There are various computational methods to estimate soil moisture and their complexity varies greatly: from one box with vertically constant volumetric soil water content to fully saturated-unsaturated coupled physically-based models. Different complexity levels are applicable depending on the simulation scale, computational time limitations, input data and knowledge about the parameters. The Vertical Equilibrium Model (VEM) is a simple approach to estimate the catchment-wide soil water storage at a daily time-scale on the basis of water table level observations, soil properties and an assumption of hydrological equilibrium without vertical fluxes above the water table. In this study VEM was extended by considering vertical fluxes, which allows conditions with evaporation and infiltration to be represented. The aim was to test the hypothesis that the simulated volumetric soil water content significantly depends on vertical fluxes. The water content difference between the no-flux, equilibrium approach and the new constant-flux approach greatly depended on the soil textural class, ranging between similar to 1% for silty clay and similar to 44% for sand at an evapotranspiration rate of 5 mm.d(-1). The two approaches gave a mean volumetric soil water content difference of 1 mm for two case studies (sandy loam and organic rich soils). The results showed that for many soil types the differences in estimated storage between the no-flux and the constant flux approaches were relatively small.

    Nyckelord
    Volumetric soil water content, Vertical flux, VEM, Catchment water storage
    Nationell ämneskategori
    Oceanografi, hydrologi och vattenresurser
    Identifikatorer
    urn:nbn:se:uu:diva-331688 (URN)10.1016/j.jhydrol.2017.08.042 (DOI)000412612700061 ()
    Forskningsfinansiär
    Vetenskapsrådet, 2011-4889
    Tillgänglig från: 2017-10-16 Skapad: 2017-10-16 Senast uppdaterad: 2018-01-13Bibliografiskt granskad
    3. Value of virtual experiments for a hillslope scale system understanding
    Öppna denna publikation i ny flik eller fönster >>Value of virtual experiments for a hillslope scale system understanding
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Oceanografi, hydrologi och vattenresurser
    Identifikatorer
    urn:nbn:se:uu:diva-331730 (URN)
    Tillgänglig från: 2017-10-17 Skapad: 2017-10-17 Senast uppdaterad: 2018-01-13
    4. Water age dependence on vertical flux assumptions
    Öppna denna publikation i ny flik eller fönster >>Water age dependence on vertical flux assumptions
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Oceanografi, hydrologi och vattenresurser
    Identifikatorer
    urn:nbn:se:uu:diva-331731 (URN)
    Tillgänglig från: 2017-10-17 Skapad: 2017-10-17 Senast uppdaterad: 2018-01-13
    5. Following tracer through the unsaturated zone using a Multiple Interacting Pathways model: implications from laboratory experiments
    Öppna denna publikation i ny flik eller fönster >>Following tracer through the unsaturated zone using a Multiple Interacting Pathways model: implications from laboratory experiments
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Oceanografi, hydrologi och vattenresurser
    Identifikatorer
    urn:nbn:se:uu:diva-331732 (URN)
    Tillgänglig från: 2017-10-17 Skapad: 2017-10-17 Senast uppdaterad: 2018-01-13
  • 16.
    Amvrosiadi, Nino
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Beven, Keith
    Bishop, Kevin
    Laudon, Hjalmar
    Seibert, Jan
    Value of virtual experiments for a hillslope scale system understandingManuskript (preprint) (Övrigt vetenskapligt)
  • 17.
    Amvrosiadi, Nino
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Beven, Keith
    Bishop, Kevin
    Seibert, Jan
    Water age dependence on vertical flux assumptionsManuskript (preprint) (Övrigt vetenskapligt)
  • 18.
    Amvrosiadi, Nino
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Bishop, Kevin
    Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, Uppsala, Sweden.
    Seibert, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Zurich, Dept Geog, Zurich, Switzerland.
    Soil moisture storage estimation based on steady vertical fluxes under equilibrium2017Ingår i: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 553, s. 798-804Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Soil moisture is an important variable for hillslope and catchment hydrology. There are various computational methods to estimate soil moisture and their complexity varies greatly: from one box with vertically constant volumetric soil water content to fully saturated-unsaturated coupled physically-based models. Different complexity levels are applicable depending on the simulation scale, computational time limitations, input data and knowledge about the parameters. The Vertical Equilibrium Model (VEM) is a simple approach to estimate the catchment-wide soil water storage at a daily time-scale on the basis of water table level observations, soil properties and an assumption of hydrological equilibrium without vertical fluxes above the water table. In this study VEM was extended by considering vertical fluxes, which allows conditions with evaporation and infiltration to be represented. The aim was to test the hypothesis that the simulated volumetric soil water content significantly depends on vertical fluxes. The water content difference between the no-flux, equilibrium approach and the new constant-flux approach greatly depended on the soil textural class, ranging between similar to 1% for silty clay and similar to 44% for sand at an evapotranspiration rate of 5 mm.d(-1). The two approaches gave a mean volumetric soil water content difference of 1 mm for two case studies (sandy loam and organic rich soils). The results showed that for many soil types the differences in estimated storage between the no-flux and the constant flux approaches were relatively small.

  • 19.
    Andersson, Elinor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Starttillståndets inverkan på hydrologisk prognososäkerhet i HYPE-modellen2016Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    SMHI:s hydrologiska prognos- och varningstjänst använder sig av meteorologiska ensembleprognoser som indata i hydrologiska modeller. De hydrologiskaensembleprognoserna tar därmed hänsyn till framtida osäkerhet i temperatur och nederbördoch används som underlag vid utfärdandet av risker och varningar för höga flöden. För närvarande beaktas dock inte osäkerheten i modellens starttillstånd, vilket består av de tillståndsvariabler i modellen som beskriver bland annat markvattenhalt och snötäcke. I dennastudie undersöktes hur starttillståndet i den hydrologiska modellen HYPE inverkar på prognoser i syfte att kvantifiera osäkerheten och på sikt möjliggöra säkrare prognoser.Studien hade tre mål: 1) Ta fram ett förslag på hur starttillståndet kan varieras för att ge en god uppskattning av prognososäkerheten relaterat till det hydrologiska starttillståndet. 2) Undersöka sambandet mellan starttillståndens spridning och det hydrologiska prognosfelet. 3) Analysera hur årstider, avrinningsområdens area, sjöprocent, skogsprocent och höjd över havet inverkar på prognososäkerheten. En central hypotes var att mindre skillnad mellan starttillståndets vattenföring och den observerade vattenföringen vid prognosstart resulterar i mer träffsäkra prognoser. Studien begränsades av att starttillstånden endast genererades med hjälp av störningar i drivdata.Indata till HYPE-modellen var femton temperatur- och nederbördsserier som manipulerats i syfte att skapa en ensemble av olika starttillstånd. Denna ensemble användes sedan för att göra vattenföringsprognoser med observerad temperatur och nederbörd som drivdata. Studien omfattade 76 avrinningsområden från hela Sverige med data för perioden 1999-2008. Prognoser utfördes varje dygn och ensemblespridningen utvärderades 2, 4 och 10 dygn in i prognosen. Samma utvärderingar utfördes även på autoregressiva prognoser, vilket innebär att modellerad rättas utefter observerad vattenföring.Resultaten indikerade ett samband mellan ensemblespridning och prognosfel, vilket innebär att spridning kan användas som ett mått på starttillståndets osäkerhet. Prognosfelet korrelerade positivt med skogsprocent och negativt med avrinningsområdenas area, sjöprocent och höjd över havet. Samma samband uppvisades mellan dessa områdesvariableroch spridning. Spridningen var störst på vintern och våren då normalisering skett med medelvattenföring över tio år, och under vår och sommar då normalisering skett med medelvattenföring per månad. Hypotesen att mindre skillnad mellan starttillståndets vattenföring och den observerade vattenföringen vid prognosstart resulterar i mer träffsäkraprognoser bekräftades av resultaten. Implementering av en ensemble av olika starttillstånd i operationella prognoser vid SMHIs hydrologiska prognos- och varningstjänst föreslås i syfte att kvantifiera osäkerheten och därigenom utöka bedömningsunderlaget vid utfärdande av risker och varningar.

  • 20.
    Andersson, Sofia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Lundkvist, Elin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Torkans effekt på dricksvattenförsörjningen i Mälarregionen: En studie om kommuners arbete med vattenfrågor utifrån erfarenheter från 20172018Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Uppsatsens syfte är att undersöka om kommuner i Mälarregionen drabbades av låga yt- och grundvattennivåer under sommaren 2017, hur situationen hanterades, deras dagliga arbete med vattenfrågor och om handlingsplaner fanns för låga nivåer före 2017. Vi vill även se hur kommunerna ställer sig till klimatförändringar samt sammanställa vilka roller och ansvar som olika myndigheter har när det kommer till vattenförsörjning. Arbetets undersökningsområde begränsades till 39 kommuner i fyra län: Södermanlands, Upplands, Västmanlands och Örebro län. För att besvara syftet skickades en enkät ut till kommunerna och intervjuer genomfördes med två av kommunerna. En litteraturstudie genomfördes för att kunna besvara ansvarsfördelningen mellan olika myndigheter. Enkäten besvarades av 26 kommuner. Det viktigaste resultat var att kommunerna, trots vattennivåer under det normala, inte upplevde vattenbrist i den omfattningen som vi trott. Fem kommuner angav att de drabbades av vattenbrist. Den huvudsakliga åtgärden som infördes var bevattningsförbud. Från enkäten framkom att det i stor utsträckning saknats handlingsplaner för att hantera en situation med vattenbrist innan 2017. Majoriteten av kommunerna tror att deras vattenförsörjning kan påverkas av klimatförändringar, men bara 14 angav att de har en handlingsplan för det. Resultatet som framkom från intervjuerna gällde främst processen för införandet av skyddsområden. Även i litteraturstudien framkom det att arbetet med vattenskyddsområden inte går i den takt som är nödvändig för att nå målen förhållbar och långsiktig dricksvattenförsörjning.

  • 21.
    Andin, Caroline
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Sundin, Madelene
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Jämförelse av Sveriges geologiska undersöknings och Naturvårdsverkets extraktionsmetoder för metaller i morän2013Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Sveriges geologiska undersökning, SGU, och Naturvårdsverket, NV, tillämpar sig av olika geokemiska extraktionsmetoder för att analysera jordprover. Detta görs för att undersöka metallhalter i mark. SGU använder en metod som liknar den som rekommenderas av NV, men utan lakning i tryckkärl, och det är oklart om metoderna lakar samma jordfraktion och kan jämföras. Syftet med arbetet är att fastställa om SGUs och NVs extraktionsmetoder för jordprover är jämförbara. Detta har gjorts genom en kvalitets- och regressionsanalys, samt genom en statistisk analys. Proverna kommer från tre olika områden i Sverige och de är analyserade med både fin- och grovfraktion. För att hitta relationer mellan metoderna har SGUs och NVs analysresultat kopplats till NVs riktvärden för förorenad mark. Detta gjordes för att undersöka hur pass jämförbara SGUs resultat är med NVs riktvärden. Det visade sig att SGUs och NVs extraktionsmetoder för jordprover korrelerar väl med varandra och att de har en god förklaringsgrad. Prov som analyserades efter NVs metod extraherade mer metall än SGUs metod. Dessutom lakades högre metallhalter ur prov av finare fraktion än prov av grövre fraktion. Sammanfattningsvis är alltså SGUs och NVs extraktionsmetoder jämförbara.

  • 22. Archfield, Stacey A.
    et al.
    Clark, Martyn
    Arheimer, Berit
    Hay, Lauren E.
    McMillan, Hilary
    Kiang, Julie E.
    Seibert, J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Hakala, Kirsti
    Bock, Andrew
    Wagener, Thorsten
    Farmer, William H.
    Andreassian, Vazken
    Attinger, Sabine
    Viglione, Alberto
    Knight, Rodney
    Markstrom, Steven
    Over, Thomas
    Accelerating advances in continental domain hydrologic modeling2015Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 51, nr 12, s. 10078-10091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the past, hydrologic modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity among the catchment, global water security, and land surface modeling communities such that these communities are converging toward continental domain hydrologic models. This commentary, written from a catchment hydrology community perspective, provides a review of progress in each community toward this achievement, identifies common challenges the communities face, and details immediate and specific areas in which these communities can mutually benefit one another from the convergence of their research perspectives. Those include: (1) creating new incentives and infrastructure to report and share model inputs, outputs, and parameters in data services and open access, machine-independent formats for model replication or reanalysis; (2) ensuring that hydrologic models have: sufficient complexity to represent the dominant physical processes and adequate representation of anthropogenic impacts on the terrestrial water cycle, a process-based approach to model parameter estimation, and appropriate parameterizations to represent large-scale fluxes and scaling behavior; (3) maintaining a balance between model complexity and data availability as well as uncertainties; and (4) quantifying and communicating significant advancements toward these modeling goals.

  • 23.
    Arnlund, Jonathan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Utredning av reningsfunktionen hos Kungsängens dagvattendamm: en studie med flödesproportionell provtagning2014Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Dagvatten kallas det regn- och smältvatten som rinner av från hårdgjorda ytor i stadsmiljön. Detta vatten för ofta med sig stora mängder av föroreningar som tungmetaller, näringsämnen och oljerelaterade ämnen, vilka kan göra stor skada om de når recipienter. För att rena dagvattnet och därmed minska föroreningsbelastningen byggs det allt fler öppna dagvattensystem som t.ex. våtmarker och dammar. Studier har visat att dessa system har hög reningseffekt och dessutom är de kostnadseffektiva. Kunskapen om hur avskiljningen i dessa system fungerar och om hur de bäst utvärderas är dock begränsad.

    Kungsängsdammen utanför Uppsala är en nybyggd dagvattenanläggning som är avsedd att rena och fördröja dagvattnet från industri- och handelsområdet Boländerna. Detta examensarbete syftar till att utreda reningsfunktionen av anläggningen. Framför allt genomfördes flödesproportionell provtagning vid inlopp och utlopp under 8 veckor. Ämnen som analyserades var näringsämnena P och N, suspenderat material, tungmetallerna As, Cd, Co, Cr, Cu, Mo, Ni, Pb, V, Zn och oljekolväten. Vid några tillfällen analyserades också de oljerelaterade organiska föreningarna PAH:er, oktyl- och nonylfenoler samt tributyltenn.

    Flödesproportionell provtagning rekommenderas för att säkert avgöra avskiljningseffektiviteten av en damm, men nackdelen är att den tar mycket tid och stora resurser i anspråk. Utöver denna metod genomfördes kompletterande mätningar med sedimentfällor samt en beräkning av föroreningsbelastning vid inloppet med programmet StormTac.

    Den flödesproportionella provtagningen visade att Kungsängsdammen fungerar väl som avskiljningsanläggning för föroreningar. Suspenderat material, näringsämnen och tungmetaller avskiljs effektivt och utloppshalterna understiger föreslagna riktvärden för dagvatten. Detta trots att både zink, koppar, kväve och suspenderat material hade inloppshalter som låg över riktvärdena. Flödesberäkningar visade att andelen av flödet som bräddas i bypass-diket förbi dammen är viktig vid bedömning av avskiljningseffektiviteten. För organiska föreningar uppmättes tributyltenn i halter över miljökvalitetsnormen för ytvatten både vid inlopp och vid utlopp. Inloppskoncentrationer framräknade i StormTac gav överensstämmande resultat med den flödesproportionella provtagningen för tungmetaller och näringsämnen. Vidare visade undersökningen av sediment att sedimentationen sker främst i fördiket och i inloppet till dammen. Fördiket är i stort behov av rensning, då sediment riskerar att spolas bort vid höga flöden.

  • 24. Aronica, Giuseppe T.
    et al.
    Apel, Heiko
    Di Baldassarre, Giuliano
    UNESCO-IHE Institute for Water Education, Delft, the Netherlands.
    Schumann, Guy J-P.
    HP - Special Issue on Flood Risk and Uncertainty2013Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 27, nr 9, s. 1291-Artikel i tidskrift (Refereegranskat)
  • 25.
    Ashkriz, Elnaz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Regional Sources of Precipitation in the Ethiopian Highlands2015Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The purpose of this essay is to investigate the origin of the large amount of precipitation that is present in the northern Ethiopian Highlands. With Moisture transport into the Ethiopian Highlands by Ellen Viste and Asgeir Sorteberg as a base, this essays intents to compare the same data but by focusing on a much smaller time scale. This frame was chosen to see if the data would deviate (i.e. a small and specific time scale versus a large and general time scale). Whilst the investigation by Viste and Sorteberg focuses on the two most rain rich months, July and August during 1998-2008, this essay focuses on only July during 2008.

                          To investigate where the precipitation originates from, this essay has analyzed different meteorological parameters such as horizontal and vertical winds at different altitudes and the moisture content of these winds.

                          This essay has like Viste’s and Sorteberg’s paper used ERA-Interim data as a basis. However the course of action has differed. This essay has made conclusions by visually drawing conclusions by studying the data images while Viste and Asgeir have drawn their conclusions by backtracking the wind to its origin.

                          This investigations results showed that great amounts of moisture were transported into the highlands from the south-west, and to some extent also from the north. While the moisture transport from the south-west was large due to the level of moist in the air, these winds where fairly small and at low altitudes. The winds from the north were visible at higher altitudes and were stronger, however they carried much less water vapor. However, exactly how much each of these winds actually contributed to producing rain is more difficult to say.

                          The results from Viste and Asgeir (2011) showed that the amount of moist that was transported into the highlands were about 46 percent more from the north compared to from the south. The contribution to moisture release within the area was however almost equally great from north and south.

                          Both investigations thus showed that the largest amount of moist was transported from the south and north. What this study did however not address was how large amount of the entire moist that had contributed to rain.

                          One anomaly of large amounts of precipitation was registered on the 20th of July 2008. This study looked closer into this which showed that large winds were registered this date as well as an upwind cell. One can presume that these winds carried large amounts of moisture, which previous results has shown, and that this might be an explanation to the large amount of precipitation that was measured on the 20th of July.

  • 26.
    Atmosudirdjo, Aryani
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Simulation of Leachate Generation from a Waste Rock Dump in Kiruna Using HYDRUS-1D2019Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The percolation of water through waste rock dumps at mine sites can lead to the production of a leachate with high concentrations of dissolved metals, sulfate and nitrogen compounds. It is important to understand how water flows in waste rock dumps in order to predict the environmental impact of this leachate on recipients. The dynamics of percolation and leachate discharge are controlled by climatological conditions at the site, where relatively large flows in northern Sweden correspond to snowmelt during late Spring. Rock dumps are often tens of meters in height, resulting in an unsaturated water flow system through heterogeneous material. Hence, the simulation of leachate generation requires an accurate representation of the subsurface materials as well as the flow processes, where water flow in waste rock dumps is dominated by matrix flow with macropore flow being of secondary importance. Matrix flow is rather slow and may thus potentially yield relatively high concentrations of contaminants in the leachate, in response to precipitation and snow melt.

    This study uses Hydrus-1D to predict leachate generation from a small-scale waste rock dump in Kiruna in terms of discharge magnitude and timing. The 3-dimensional geometry of the waste rock dump is approximated by summing simulations from 1225 one-dimensional columns of different length, with a surface area of 1 m2 each. There are four output parameters that are compared between the model results and measured data: snow accumulation, water content, temperature, and discharge. There are some discrepancies between the model results and field measurements, most likely due to uncertainties in the input parameters (especially waste rock properties), limitations in the Hydrus-1D model (i.e. freeze-thaw dynamics), and assumptions that are used in constructing the conceptual model. For better agreement between model results and measured data, a new modelling approach is recommended, potentially using a different program than Hydrus-1D.

  • 27.
    Attermeyer, Katrin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Andersson, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Catalán, Núria
    Catalan Institute for Water Research (ICRA), Girona, Spain.
    Einarsdóttir, Karólina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Groeneveld, Marloes M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Szekely, Anna J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Tranvik, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Potential terrestrial influence on transparent exopolymer particle (TEP) concentrations in boreal freshwaters2019Ingår i: Journal of limnology, ISSN 1129-5767, E-ISSN 1723-8633Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transparent exopolymer particles (TEP) are ubiquitous in aquatic ecosystems and contribute, for example, to sedimentation of organic matter in oceans and freshwaters. Earlier studies indicate that the formation of TEP is related to the in situ activity of phytoplankton or bacteria. However, terrestrial sources of TEP and TEP precursors are usually not considered. We investigated TEP concentration and its driving factors in boreal freshwaters, hypoth- esizing that TEP and TEP precursors can enter freshwaters via terrestrial inputs. In a field survey, we measured TEP concentrations and other environmental factors across 30 aquatic ecosystems in Sweden. In a mesocosm experi- ment, we further investigated TEP dynamics over time after manipulating terrestrial organic matter input and light conditions. The TEP concentrations in boreal freshwaters ranged from 83 to 4940 μg Gum Xanthan equivalent L−1, which is comparable to other studies in freshwaters. The carbon fraction in TEP in the sampled boreal freshwaters is much higher than the phytoplanktonic carbon, in contrast to previous studies in northern temperate and Medi- terranean regions. Boreal TEP concentrations were mostly related to particulate organic carbon, dissolved organic carbon, and optical indices of terrestrial influence but less influenced by bacterial abundance, bacterial production, and chlorophyll a. Hence, our results do not support a major role of the phytoplankton community or aquatic bac- teria on TEP concentrations and dynamics. This suggests a strong external control of TEP concentrations in boreal freshwaters, which can in turn affect particle dynamics and sedimentation in the recipient aquatic ecosystem.

  • 28.
    Attermeyer, Katrin
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi. Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Chemical Analytics and Biogeochemistry, Germany.
    Grossart, Hans-Peter
    Leibniz-Institute of Freshwater Ecology and InlandFisheries, Experimental Limnology, Germany; Institute for Biochemistry and Biology, Potsdam University, Germany.
    Flury, Sabine
    Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Chemical Analytics and Biogeochemistry, Germany; Faculty of Science, University of Geneva, Switzerland.
    Premke, Katrin
    Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Chemical Analytics and Biogeochemistry, Germany; Leibniz Centre for Agricultural Landscape Research (ZALF), Institute for Landscape Biogeochemistry, Germany.
    Bacterial processes and biogeochemical changes in the water body of kettle holes: mainly driven by autochthonous organic matter?2017Ingår i: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 79, nr 3, s. 675-687Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Kettle holes are small inland waters formed from glacially-created depressions often situated in agricultural landscapes. Due to their high perimeter-to-area ratio facilitating a high aquatic-terrestrial coupling, kettle holes can accumulate high concentrations of organic carbon and nutrients, fueling microbial activities and turnover rates. Thus, they represent hotspots of carbon turnover in the landscape, but their bacterial activities and controlling factors have not been well investigated. Therefore, we aimed to assess the relative importance of various environmental factors on bacterial and biogeochemical processes in the water column of kettle holes and to disentangle their variations. In the water body of ten kettle holes in north-eastern Germany, we measured several physico-chemical and biological parameters such as carbon quantity and quality, as well as bacterial protein production (BP) and community respiration (CR) in spring, early summer and autumn 2014. Particulate organic matter served as an indicator of autochthonous production and represented an important parameter to explain variations in BP and CR. This notion is supported by qualitative absorbance indices of dissolved molecules in water samples and C:N ratios of the sediments, which demonstrate high fractions of autochthonous organic matter (OM) in the studied kettle holes. In contrast, dissolved chemical parameters were less important for bacterial activities although they revealed strong differences throughout the growing season. Pelagic bacterial activities and dynamics might thus be regulated by autochthonous OM in kettle holes implying a control of important biogeochemical processes by internal primary production rather than facilitated exchange with the terrestrial surrounding due to a high perimeter-to-area ratio.

  • 29.
    Basirat, Farzad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Process Models for CO2 Migration and Leakage: Gas Transport, Pore-Scale Displacement and Effects of Impurities2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Geological Carbon Storage (GCS) is considered as one of the key techniques to reduce the rate of atmospheric emissions of CO2 and thereby to contribute to controlling the global warming. A successful application of a GCS project requires the capability of the formation to trap CO2 for a long term. In this context, processes related to CO2 trapping and also possible leakage of CO2 to the near surface environment need to be understood. The overall aim of this thesis is to understand the flow and transport of CO2 through porous media in the context of geological storage of CO2. The entire range of scales, including the pore scale, the laboratory scale, the field experiment scale and the industrial scale of CO2 injection operation are addressed, and some of the key processes investigated by means of experiments and modeling.  First, a numerical model and laboratory experimental setup were developed to investigate the CO2 gas flow, mimicking the system in the near-surface conditions in case a leak from the storage formation should occur. The system specifically addressed the coupled flow and mass transport of gaseous CO2 both in the porous domain as well as the free flow domain above it. The comparison of experiments and modelling results showed a very good agreement indicating that the model developed can be applied to evaluate monitoring and surface detection of potential CO2 leakage. Second, the field scale CO2 injection test carried out in a shallow aquifer in Maguelone, France was analyzed and modeled. The results showed that Monte Carlo simulations accounting for the heterogeneity effects of the permeability field did capture the key observations of the monitoring data, while a homogeneous model could not represent them. Third, a numerical model based on phase-field method was developed and model simulations carried out addressing the effect of wettability on CO2-brine displacement at the pore-scale. The results show that strongly water-wet reservoirs provide a better potential for the dissolution trapping, due to the increase of interface between CO2 and brine with very low contact angles. The results further showed that strong water-wet conditions also imply a strong capillary effect, which is important for residual trapping of CO2. Finally, numerical model development and model simulations were carried out to address the large scale geological storage of CO2 in the presence of impurity gases in the CO2 rich phase. The results showed that impurity gases N2 and CH4 affected the spatial distribution of the gas (the supercritical CO2 rich phase), and a larger volume of reservoir is needed in comparison to the pure CO2 injection scenario. In addition, the solubility trapping significantly increased in the presence of N2 and CH4

    Delarbeten
    1. Experimental and modeling investigation of CO2 flow and transport in a coupled domain of porous media and free flow
    Öppna denna publikation i ny flik eller fönster >>Experimental and modeling investigation of CO2 flow and transport in a coupled domain of porous media and free flow
    2015 (Engelska)Ingår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 42, s. 461-470Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A solid understanding of the transport mechanisms of gaseous CO2 near the land surface is necessary for developing reliable monitoring techniques and predictive models for possible CO2 leakage from deep underground storage. The objective of this work has been to develop an experimental method along with a simulation model for gaseous CO2 flow and transport in a system including both the porous media and the free air space above it. The experimental system consisted of a two-dimensional bench scale rectangular sandbox containing homogenous sand with an open space of still air above it. Gaseous CO2 was injected in different modes and the CO2 breakthrough was measured on specified ports in the system by using CO2 concentration sensors. A numerical model combining the gas flow in the porous medium and the free flow region was developed and used to model the experimental data. In this quest, the Discontinuous One-Domain approach was selected for modeling transport between the free flow and porous regions. The observed and simulated CO2 breakthrough curves both in the dried sand and in the free flow matched very well in the case of uniform injection and satisfactorily even in the case of point injection. Consequently, it seems that the model reasonably matches the observed data in the cases where the boundary condition is well defined. In summary, our results show that the developed experimental setup provides capability to study gaseous CO2 flow and transport in a coupled porous medium - free flow system and that our modeling approach is able to predict the flow and transport in this system with good accuracy.

    Nyckelord
    Carbon dioxide flow and transport, Coupling conditions, Discontinuous One-Domain Approach, Experimental method, Free flow, Porous media
    Nationell ämneskategori
    Energiteknik
    Identifikatorer
    urn:nbn:se:uu:diva-274707 (URN)10.1016/j.ijggc.2015.08.024 (DOI)000366947400041 ()
    Forskningsfinansiär
    EU, FP7, Sjunde ramprogrammet, 282900Vetenskapsrådet, 2010-3657
    Tillgänglig från: 2016-02-02 Skapad: 2016-01-25 Senast uppdaterad: 2017-11-30
    2. Numerical modelling of CO2 injection at small-scale field experimental site in Maguelone, France
    Öppna denna publikation i ny flik eller fönster >>Numerical modelling of CO2 injection at small-scale field experimental site in Maguelone, France
    Visa övriga...
    2016 (Engelska)Ingår i: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 54, s. 200-210Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    To evaluate the performance of downhole and surface geophysical monitoring methods, a series of shallow gas injection-monitoring experiments has been performed in a coastal saline aquifer at Maguelone, France. The recorded data include pressure measurements with a Westbay multilevel completion and CO2 saturation at an observation well derived from electrical resistivity with a modified Waxman-Smits (MWS) model. In this work, the aim is to develop a simulation model capturing the gas transport behavior and consistent with field data. For this purpose, the simulation of the CO2 injection experiment is carried out with two conceptual models, a homogeneous model and a heterogeneous model treated with multiple realization Monte Carlo simulations. Numerical simulator TOUGH2 with the equation of state module EOS7C is used for the simulations. Comparison of the model results with field data suggests that the pressure responses are captured with relatively good accuracy. Similarly, the model also provides an overall reasonable agreement and correct order of magnitude for predicted gas saturation values. However, as the heterogeneity pattern in the field data remains largely unknown, the model predictions can only be used to capture the mean behavior as well as to provide insights into how heterogeneity can influence the system behavior, by means of sensitivity analyses of the influence of heterogeneities on individual realizations.

    Nyckelord
    CO2 storage, CO2 injection, Shallow aquifer, Downhole and pressure monitoring, Numerical simulation, Heterogeneity, Electrical resistivity, Downhole geophysical monitoring
    Nationell ämneskategori
    Multidisciplinär geovetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-311204 (URN)10.1016/j.ijggc.2016.09.006 (DOI)000387781500015 ()
    Forskningsfinansiär
    EU, FP7, Sjunde ramprogrammet, 227286 309367
    Tillgänglig från: 2016-12-22 Skapad: 2016-12-22 Senast uppdaterad: 2017-11-29
    3. Pore-scale modeling of wettability effects on CO2–brine displacement during geological storage
    Öppna denna publikation i ny flik eller fönster >>Pore-scale modeling of wettability effects on CO2–brine displacement during geological storage
    2017 (Engelska)Ingår i: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 109, s. 181-195Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Wetting properties of reservoir rocks and caprocks can vary significantly, and they strongly influence geological storage of carbon dioxide in deep saline aquifers, during which CO2 is supposed to displace the resident brine and to become permanently trapped. Fundamental understanding of the effect of wettability on CO2-brine displacement is thus important for improving storage efficiency and security. In this study, we investigate the influence of wetting properties on two-phase flow of CO2 and brine at the pore scale. A numerical model based on the phase field method is implemented to simulate the two-phase flow of CO2-brine in a realistic pore geometry. Our focus is to study the pore-scale fluid-fluid displacement mechanisms under different wetting conditions and to quantify the effect of wettability on macroscopic parameters such as residual brine saturation, capillary pressure, relative permeability, and specific interfacial area. Our simulation results confirm that both the trapped wetting phase saturation and the normalized interfacial area increase with decreasing contact angle. However, the wetting condition does not appear to influence the CO2 breakthrough time and saturation. We also show that the macroscopic capillary pressures based on the pressure difference between inlet and outlet can differ significantly from the phase averaging capillary pressures for all contact angles when the capillary number is high ( log Ca > -5). This indicates that the inlet-outlet pressure difference may not be a good measure of the continuum-scale capillary pressure. In addition, the results show that the relative permeability of CO2 can be significantly lower in strongly water-wet conditions than in the intermediate-wet conditions.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2017
    Nationell ämneskategori
    Oceanografi, hydrologi och vattenresurser
    Forskningsämne
    Hydrologi
    Identifikatorer
    urn:nbn:se:uu:diva-315304 (URN)10.1016/j.advwatres.2017.09.004 (DOI)000416037100014 ()
    Forskningsfinansiär
    EU, FP7, Sjunde ramprogrammet, 309067Vetenskapsrådet, 637-2014-445Energimyndigheten, 43526-1
    Tillgänglig från: 2017-02-14 Skapad: 2017-02-14 Senast uppdaterad: 2018-02-23Bibliografiskt granskad
    4. Numerical simulation of geological storage of CO2 with impurities in large scale saline aquifer
    Öppna denna publikation i ny flik eller fönster >>Numerical simulation of geological storage of CO2 with impurities in large scale saline aquifer
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract
    Nationell ämneskategori
    Vattenteknik Oceanografi, hydrologi och vattenresurser
    Identifikatorer
    urn:nbn:se:uu:diva-315303 (URN)
    Tillgänglig från: 2017-02-14 Skapad: 2017-02-14 Senast uppdaterad: 2018-01-13
  • 30.
    Basirat, Farzad
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Jung, Byeongju
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Institute of Geoscience and Mineral Resources (KIGAM), Daejeon, South Korea.
    Yang, Zhibing
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Niemi, Auli
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Numerical simulation of geological storage of CO2 with impurities in large scale saline aquiferManuskript (preprint) (Övrigt vetenskapligt)
    Abstract
  • 31.
    Basirat, Farzad
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Yang, Zhibing
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
    Niemi, Auli
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Pore-scale modeling of wettability effects on CO2–brine displacement during geological storage2017Ingår i: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 109, s. 181-195Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wetting properties of reservoir rocks and caprocks can vary significantly, and they strongly influence geological storage of carbon dioxide in deep saline aquifers, during which CO2 is supposed to displace the resident brine and to become permanently trapped. Fundamental understanding of the effect of wettability on CO2-brine displacement is thus important for improving storage efficiency and security. In this study, we investigate the influence of wetting properties on two-phase flow of CO2 and brine at the pore scale. A numerical model based on the phase field method is implemented to simulate the two-phase flow of CO2-brine in a realistic pore geometry. Our focus is to study the pore-scale fluid-fluid displacement mechanisms under different wetting conditions and to quantify the effect of wettability on macroscopic parameters such as residual brine saturation, capillary pressure, relative permeability, and specific interfacial area. Our simulation results confirm that both the trapped wetting phase saturation and the normalized interfacial area increase with decreasing contact angle. However, the wetting condition does not appear to influence the CO2 breakthrough time and saturation. We also show that the macroscopic capillary pressures based on the pressure difference between inlet and outlet can differ significantly from the phase averaging capillary pressures for all contact angles when the capillary number is high ( log Ca > -5). This indicates that the inlet-outlet pressure difference may not be a good measure of the continuum-scale capillary pressure. In addition, the results show that the relative permeability of CO2 can be significantly lower in strongly water-wet conditions than in the intermediate-wet conditions.

  • 32.
    Bastviken, Paulina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Flood Risk Mapping in Africa: Exploring the Potentials and Limitations of SRTM Data in the Lower Limpopo, Mozambique2016Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Många  områden  i  Afrika  står  för  närvarande  inför  en  ökad  översvämningsrisk  på  grund  avklimatförändringar och befolkningstillväxt. En användbar strategi att minska denna risk skulle vara att kartlägga den, så att stadsplanering, varningssystem och respons vid nödsituationer därefter skulle kunna utformas till att begränsa samhällets sårbarhet. Detta är dock inte möjligt på bred front över Afrikas kontinent, då utvecklingsländer ofta saknar det data av topografi och vattenflöde som behövs för producera högkvalitativa översvämningsriskkartor. För att försöka hitta ett sätt att kringgå detta problem undersöker pågående forskning möjligheten att generera alternativ modelleringsinput, från globalt tillgängligt höjddata, insamlat av satelliter, och metoder att uppskatta översvämningsflöden. Denna uppsats presenterar en fallstudie inom denna kontext där syftet var att bestämma kvalitén hos en översvämningskarta över ett Afrikanskt avrinningsområde, producerad med satellitprodukten SRTM (Shuttle Radar Topography Mission) som topografiinput, och att utforska möjligheterna och begränsningarna med en sådan karteringsmodell. Två stora översvämningar, vilka inträffade år 2000 och 2013 i Nedre Limpopobassängen (Mocambique), simulerades för utbredning med hjälp av en 2D- model utan flodfåra byggd för modelleringsprogrammet LISFLOOD-FP. Vattennivåer simulerade också för att kunna bedöma modellens vertikala prestation. Resultaten jämfördes med satellitbilder och dokumenterade höga vattenmärken (observerade på t ex. husfasader), samtidigt som flodplanets flödesmotstånd justerades för att optimera överensstämmelsen. Då översvämningarna var av olika karaktär behövdes olika flödesmotstånd (0.02 and 0.09 s m-1/3) för att maximal kvalité på respektive översvämningskarta skulle uppnås. Denna kvalité beräknades till 0.59 och 0.64, på en index-skala (F) där 1.00 motsvarar en perfekt simulering. Trots olika optimala flödesmotstånd antydde resultaten även att en modell kalibrerad med en relativt frekvent återkommande översvämning möjligtvis kan användas till att kartlägga sällsynta översvämningar. Avvikelserna mellan dokumenterad och simulerad översvämningsutbredning tillskrevs i huvudsak: (1) sjöar och vattendrag som temporärt ansluter till flodsystemet under höga flöden, (2) begränsningar i topografidatat gällande att fånga flodens geometri och flodplanets mikro-topografi samt (3) moln som skymmer översvämningarna i referensdatat och minskar dess sanningshalt. Vattennivåer simulerades med ett genomsnittligt fel av±2 m, vilket med marginal ligger inom inputdatats totala osäkerhetsram. Avvikelserna troddes i detta fall bero på SRTM-datats representation av sluttande terräng och möjliga radarfläckar (reflektioner) i urbana områden. Resultaten i denna studie indikerar att det ligger stor potential i att använda SRTM- data för att kartlägga risken för stora översvämningar i Afrika, men belyser också vikten av attuppmärksamhet ges till flodsystems komplexitet.

  • 33.
    Bastviken, Paulina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Soil water solution DOC dynamics during winter in boreal hillslopes2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    When plants and animals die they are decomposed into microscopic particles of organic carbon. In the ground, these carbon particles are dissolved in the soil water and eventually transported to the streamchannel with the flow of the groundwater. Today the quantities of dissolved organic carbon (DOC) have been observed to increase in many lakes and streams around the world, which constitute a threat against the water quality and ecologic environment of these surface waters. The amount of organic carbon that is dissolved and transported in the soil water is mainly controlled by processes related to temperature and hydrology, two factors which vary seasonally. Because of difficulties to sample soil water at temperatures below 0°C studies of DOC transport between soil and water during the winter season are limited. This study therefore conducted a winter sampling of soil water, with the focus on DOC. Samples were collected in March 2014 at sites along three hillslopes, orthogonal to two streams, in a typical Swedish boreal forest northwest of Umeå. The soil water was extracted with the help of suction lysimeters installed at different depths in the soil, and heating equipmentpowered by batteries. The collected samples were analyzed for DOC concentration and absorbance after which the results were grouped together with results from previous sampling campaigns, conducted in the summer and autumn of 2013. Parallel to this, data representing a longer time series (2009 to 2012) at another hillslope was processed. During the summer and autumn an increase in DOC concentration was observed. The increase was assumed to be caused by high production and effective degradation of organic matter in the soil during this warm period. Generally, a decrease in the DOC concentration then followed during the winter season. One possible reason for this decrease could be that the bacterial degradation in the soil continued, during the winter, and transformed the dissolved carbon into CO2 and CH4. Another possibility is that the DOC was flushed into the streams by autumn rain events. The study also found differences concerning the DOC concentration and character in the soil water, as well as the seasonal variation of these parameters, with soil depth and distance from the stream along the hillslope profile. These differences could be correlated to the organic content of the soil, from which the soil water had been extracted.

  • 34.
    Beckholmen, Ingrid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Källor i Lagga, en uppländsk slättbygd: Geografisk och geologisk påverkan påkällvattens egenskaper2014Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Källor har under århundraden spelat en viktig roll i människors liv genom behovet av vattenförsörjning, vid val av plats för att bosätta sig och inom folkloristiken. Källors förekomst styrs av var och hur de uppträder; t ex i vilken sorts jordart utströmningen sker. Den geografiska och geologiska närkemin påverkar källvattenkemin. I detta projekt undersöktes källor i Lagga socken, Knivsta kommun. Källvattenprover samlades in för analys av vattenkemin. En kort tidsserie under våren 2014 för temperatur och konduktivitet upprättades. Källorna delades in i fyra större grupper efter hur de ligger i landskapet och efter deras kemiska egenskaper: 1) Källor som kommer upp genom leran i dalgången, 2) källor som ligger i kanten av lerslätten, 3) källor som ligger i morän och 4) i storblockig morän. Efter analys visas att källor nära och i dalgången har högre jonhalt än de källor som ligger i moränen, uppe i skogarna. Vid en jämförelse med tidigare mätdata ser man att temperatur och konduktivitet är stabilare i källor som kommer ut i den leriga dalgången än i moränkällorna.

  • 35. Beldring, Stein
    et al.
    Gottschalk, Lars
    Rodhe, Allan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Tallaksen, Lena M.
    Kinematic wave approximations to hillslope hydrological processes in tills2000Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 14, nr 4, s. 727-745Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work has been carried out within the framework of NOPEX - a NOrthern hemisphere climate Processes land surface EXperiment. Its purpose is to describe the spatial variability of groundwater levels and soil moisture content and their influence on runoff generation in small catchments in a landscape dominated by boreal forest and till soils, which is characteristic for the Nordic countries. Kinematic wave approximations have been used to describe saturated subsurface flow and saturation overland flow in hillslopes with a thin soil layer overlying a relatively impermeable bedrock. Simultaneous analyses of catchment runoff, groundwater-table depths and soil moisture in the unsaturated zone have been performed by including the kinematic wave descriptions in a precipitation-runoff model. The results have been compared with observed hydrographs and spatial patterns of groundwater levels and soil moisture content in two small experimental catchments. Results from this study indicate that is reasonable to apply the same parameter set when describing hydrological processes in computational elements with similar characteristics at a scale of about 1 km(2) in the NOPEX area. 

  • 36.
    Beldring, Stein
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft- och vattenlära.
    Rodhe, Allan
    Tallaksen, Lena
    Kinematic wave approximations to hillslope hydrological processes in till soils2000Ingår i: Hydrological Processes, Vol. 14, s. 727-745Artikel i tidskrift (Refereegranskat)
  • 37. Benner, S G
    et al.
    Blowes, D W
    Gould, W D
    Herbert, Roger B
    Ptacek, C J
    Geochemistry of a permeable reactive barrier for metals and acid mine drainage1999Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 33, nr 16, s. 2793-2799Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A permeable reactive barrier, designed to remove metals and generate alkalinity by promoting sulfate reduction and metal sulfide precipitation, was installed in August 1995 into an aquifer containing effluent from mine tailings. Passage of groundwater through the barrier results in striking improvement in water quality. Dramatic changes in concentrations of SO4 (decrease of 2000−3000 mg/L), Fe (decrease of 270−1300 mg/L), trace metals (e.g., Ni decreases 30 mg/L), and alkalinity (increase of 800−2700 mg/L) are observed. Populations of sulfate reducing bacteria are 10 000 times greater, and bacterial activity, as measured by dehydrogenase activity, is 10 times higher within the barrier compared to the up-gradient aquifer. Dissolved sulfide concentrations increase by 0.2−120 mg/L, and the isotope 34S is enriched relative to 32S in the dissolved phase SO42- within the barrier. Water chemistry, coupled with geochemical speciation modeling, indicates the pore water in the barrier becomes supersaturated with respect to amorphous Fe sulfide. Solid phase analysis of the reactive mixture indicates the accumulation of Fe monosulfide precipitates. Shifts in the saturation states of carbonate, sulfate, and sulfide minerals and most of the observed changes in water chemistry in the barrier and down-gradient aquifer can be attributed, either directly or indirectly, to bacterially mediated sulfate reduction.

  • 38.
    Bennich, David
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Bredberg, William
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Olsson, Jimmy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Rulewski Stenberg, Louis
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Smith, Malin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Söderqvist, Johnny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    En jämförelse mellan fjärranalystekniker och vågbojar för mätning av oceanografiska parametrar i svenska vatten2017Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    För övervakning av svenska vatten krävs noggranna mätningar av oceanografiska parametrar såsom våghöjd, vågriktning, ytvattentemperatur och ytströmmar. Mätdata för parametrarna samlas in av Sveriges Meteorologiska och Hydrologiska Institut (SMHI) och används till prognoser, sjöfart samt forskning. I denna studie undersöktes möjligheten att ersätta eller komplettera vågbojarna av modellen Directional Waverider MkIII som SMHI använder idag, med ny kommersiellt tillgänglig fjärranalysteknik. Projektet begränsades till att studera två högfrekvens-radartekniker och en X-bandradar. Studien är platsspecifik och utreder kvalitetsmässiga, ekonomiska och miljömässiga för- och nackdelar med de utvalda radarteknikerna i relation till vågbojarna. En litteraturstudie och modellering av data över parametrar som påverkar radarteknikernas räckvidd och datatillgänglighet genomfördes. Ur modelleringen drogs slutsatsen att det är möjligt att erhålla likvärdig datatillgänglighet med vågradar som med vågboj. Vidare modellering ledde till slutsatsen att radarteknikerna begränsas till ungefär hälften av sin optimala räckvidd i Östersjön på grund av den låga salthalten, och därför är Sveriges västkust bättre lämpad för placering av radarteknik. Undersökning av isbildning i havsvatten, som kan begränsa radarteknikernas räckvidd, ledde till slutsatsen att Sveriges västkust också är att föredra utifrån detta perspektiv. Med anledning av radarteknikers möjlighet att utföra mätningar över större områden, finner studien att det finns goda grunder för att motivera en ersättning eller komplettering av vågbojarna med modern radarteknik. Vidare talar radarteknikernas goda anpassningsförmåga, lägre inverkan på miljön och enklare underhållskrav jämfört med vågbojarna till dess fördel. Att övergå till radarteknik medför däremot högre installations- och driftkostnader i jämförelse med vågbojar.

  • 39.
    Berga, Mercè
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi. Biological Oceanography, Leibniz Institute for Baltic Sea Research Warnemünde, Germany.
    Zha, Yinghua
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Székely, Anna J.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Langenheder, Silke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Functional and Compositional Stability of Bacterial Metacommunities in Response to Salinity Changes2017Ingår i: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 8, artikel-id 948Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Disturbances and environmental change are important factors determining the diversity,composition, and functioning of communities. However, knowledge about how naturalbacterial communities are affected by such perturbations is still sparse. We performeda whole ecosystem manipulation experiment with freshwater rock pools where weapplied salinity disturbances of different intensities. The aim was to test how thecompositional and functional resistance and resilience of bacterial communities,alpha- and beta-diversity and the relative importance of stochastic and deterministiccommunity assembly processes changed along a disturbance intensity gradient.We found that bacterial communities were functionally resistant to all salinity levels (3, 6, and 12 psu) and compositionally resistant to a salinity increase to 3 psu andresilient to increases of 6 and 12 psu. Increasing salinities had no effect on local richnessand evenness, beta-diversity and the proportion of deterministically vs. stochasticallyassembled communities. Our results show a high functional and compositional stabilityof bacterial communities to salinity changes of different intensities both at localand regional scales, which possibly reflects long-term adaptation to environmentalconditions in the study system.

  • 40.
    Berghuijs, Wouter R.
    et al.
    Department of Civil Engineering, University of Bristol, Bristol, UK.
    Harrigan, Shaun
    Irish Climate Analysis and Research Units (ICARUS), Department of Geography, Maynooth University, Maynooth, Ireland.
    Kipnis, Evan L.
    Department of Ecosystem Science and Management, University of Wyoming, Laramie, Wyoming, USA.
    Dogulu, Nilay
    Department of Civil Engineering, Middle East Technical University, Ankara, Turkey.
    Floriancic, Marius
    Institute of Environmental Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland.
    Müller, Hannes
    Institute of Water Resources Management, Hydrology and Agricultural Hydraulic Engineering, Leibniz Universität Hannover, Hanover, Germany.
    Pohle, Ina
    Chair of Hydrology and Water Resources Management, Brandenburg University of Technology Cottbus-Senftenberg, Cottbus, Germany .
    Saia, Sheila M.
    Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, USA.
    Sedlar, Frank
    Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, USA.
    Smoorenburg, Maarten
    Institute of Environmental Engineering, Swiss Federal Institute of Technology, Zurich, Switzerland.
    Teutschbein, Claudia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    van Emmerik, Tim
    Water resources section, Faculty of Civil Engineering and Geosciences, Delft University of Technology, The Netherlands.
    Creating Community for Early-Career Geoscientists: Student involvement in geoscience unions: A case study from hydrology2015Ingår i: EOS: Transactions, ISSN 0096-3941, E-ISSN 2324-9250, Vol. 96Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The American Geophysical Union (AGU) and the European Geosciences Union (EGU) play central roles in nurturing the next generation of geoscientists. Students and young scientists make up about one quarter of the unions’ active memberships [American Geophysical Union, 2013; European Geosciences Union, 2014], creating a major opportunity to include a new generation of geoscientists as more active contributors to the organizations’ activities, rather than merely as consumers.

    Both organizations are now explicitly expanding their bottom-up organizational structures to include early-career members (ECMs) by appointing student (AGU) and early-career scientist (EGU) representatives for their scientific divisions. (We refer to “early-career members” because AGU and EGU define student and postdoc members differently). Because this expansion is a recent development, it is still unclear what roles these representatives will play and how these roles will evolve over the coming years.

    We are ECMs in the hydrological sciences. Here we show how the Young Hydrological Society (YHS) used bottom-up initiatives, aligned closely with the newly appointed AGU and EGU representatives, to help improve the professional development of student and postdoc members by providing opportunities to increase their contributions to the geoscience unions. We call for a conversation on how ECMs can make the best use of these new opportunities to engage proactively with the unions.

  • 41.
    Bergström, Carolin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Vattenkemisk undersökning i Lissån2016Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Vattenkemin i vattendrag förändras ständigt och processer som vattenföring, klimatförändringar och antropogena processer kan komma att påverka vattnets kemiska sammansättning.

    I arbetet har det undersöks hur vattenkemin förändras i Lissån under våren med avseende på den elektriska konduktiviteten. Det har dessutom tagits till hänsyn vad för källor i avrinningsområdet som kan kommat att påverka en möjlig förändring i den elektriska konduktiviteten.

    Under vintern i samband med snösmältningen ökar flödena i Uppsalas vattendrag för att under våren avta. Denna förändring i flöde påverkar vattenföringens storlek vilken i sin tur har betydelse på den elektriska konduktiviteten och vattendragens kemiska sammansättning. Inom avrinningsområdet ligger dessutom Hovgården avfallsanläggning som är en potentiell källa till en möjlig förändrad kemisk sammansättning i Lissån. Renat lakvatten från anläggningen släpps ut i Hovgårdsbäcken som ansluter till recipienten Lissån vilket kan vara en orsak till förändrad elektrisk konduktivitet.

    Under våren har provtagningar tagits i Lissån vid Fribacken vilka har jämförts med provtagningar gjorda i anslutning till där Hovgårdsbäcken sammanflödar med Lissån, uppströms provtagningsplatsen vid Fribacken. Vattenkemin och den elektriska konduktiviteten i Lissån bedöms påverkas av vattenföringens storlek och till viss grad även av utsläppen från avfallsanläggningen.Resultaten visar att i samband med ökad vattenföring sjunker den elektriska konduktiviteten. Vattenföringen ökar dessutom något i samband med ökad nederbördsmängd.

    Resultatet visar inte bara på hur antropogena processer såsom utsläpp från avfallsanläggningar kan påverka vattnet i vattendrag utan även hur klimatförändringar kan komma att påverka vattnets kvalitet i framtiden.

  • 42.
    Beven, Keith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Lancaster, Lancaster Environm Ctr, Lancaster, England..
    Advice to a young hydrologist2016Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 30, nr 20, s. 3578-3582Artikel i tidskrift (Övrigt vetenskapligt)
  • 43.
    Beven, Keith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Lancaster, Lancaster Environm Ctr, Lancaster, England..
    Facets of uncertainty: epistemic uncertainty, non-stationarity, likelihood, hypothesis testing, and communication2016Ingår i: Hydrological Sciences Journal, ISSN 0262-6667, E-ISSN 2150-3435, Vol. 61, nr 9, s. 1652-1665Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a discussion of some of the issues associated with the multiple sources of uncertainty and non-stationarity in the analysis and modelling of hydrological systems. Different forms of aleatory, epistemic, semantic, and ontological uncertainty are defined. The potential for epistemic uncertainties to induce disinformation in calibration data and arbitrary non-stationarities in model error characteristics, and surprises in predicting the future, are discussed in the context of other forms of non-stationarity. It is suggested that a condition tree is used to be explicit about the assumptions that underlie any assessment of uncertainty. This also provides an audit trail for providing evidence to decision makers.

  • 44.
    Beven, Keith
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    So how much of your error is epistemic? Lessons from Japan and Italy2013Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 27, nr 11, s. 1677-1680Artikel i tidskrift (Övrigt vetenskapligt)
  • 45.
    Beven, Keith
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Lancaster Environment Centre, Lancaster University, Lancaster, UK.
    Almeida, Susana
    Univ Bristol, Dept Civil Engn, Bristol, Avon, England.
    Aspinall, Willy P.
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Bates, Paul D.
    Univ Bristol, Sch Geog Sci, Bristol, Avon, England.
    Blazkova, Sarka
    TG Masaryk Water Resource Inst, Prague, Czech Republic.
    Borgomeo, Edoardo
    Univ Oxford, Environm Change Inst, Oxford, England.
    Freer, Jim
    Univ Bristol, Sch Geog Sci, Bristol, Avon, England.
    Goda, Katsuichiro
    Univ Bristol, Dept Civil Engn, Bristol, Avon, England.
    Hall, Jimw.
    Univ Oxford, Environm Change Inst, Oxford, England.
    Phillips, Jeremy C.
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Simpson, Michael
    Univ Oxford, Environm Change Inst, Oxford, England.
    Smith, Paul J.
    Univ Lancaster, Lancaster Environm Ctr, Lancaster, England;Waternumbers Ltd, Halton Mill, Lancaster LA2 6DN, England.
    Stephenson, David B.
    Univ Exeter, Dept Math & Comp Sci, Exeter, Devon, England.
    Wagener, Thorsten
    Univ Bristol, Dept Civil Engn, Bristol, Avon, England;Univ Bristol, Cabot Inst, Bristol, Avon, England.
    Watson, Matt
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Wilkins, Kate L.
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Epistemic uncertainties and natural hazard risk assessment - Part 1: A review of different natural hazard areas2018Ingår i: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 18, nr 10, s. 2741-2768Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    This paper discusses how epistemic uncertainties are currently considered in the most widely occurring natural hazard areas, including floods, landslides and debris flows, dam safety, droughts, earthquakes, tsunamis, volcanic ash clouds and pyroclastic flows, and wind storms. Our aim is to provide an overview of the types of epistemic uncertainty in the analysis of these natural hazards and to discuss how they have been treated so far to bring out some commonalities and differences. The breadth of our study makes it difficult to go into great detail on each aspect covered here; hence the focus lies on providing an overview and on citing key literature. We find that in current probabilistic approaches to the problem, uncertainties are all too often treated as if, at some fundamental level, they are aleatory in nature. This can be a tempting choice when knowledge of more complex structures is difficult to determine but not acknowledging the epistemic nature of many sources of uncertainty will compromise any risk analysis. We do not imply that probabilistic uncertainty estimation necessarily ignores the epistemic nature of uncertainties in natural hazards; expert elicitation for example can be set within a probabilistic framework to do just that. However, we suggest that the use of simple aleatory distributional models, common in current practice, will underestimate the potential variability in assessing hazards, consequences, and risks. A commonality across all approaches is that every analysis is necessarily conditional on the assumptions made about the nature of the sources of epistemic uncertainty. It is therefore important to record the assumptions made and to evaluate their impact on the uncertainty estimate. Additional guidelines for good practice based on this review are suggested in the companion paper (Part 2).

  • 46.
    Beven, Keith
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Lancaster, Lancaster Environm Ctr, Lancaster, England.
    Aspinall, Willy P.
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Bates, Paul D.
    Univ Bristol, Sch Geog Sci, Bristol, Avon, England.
    Borgomeo, Edoardo
    Univ Oxford, Environm Change Inst, Oxford, England.
    Goda, Katsuichiro
    Univ Bristol, Dept Civil Engn, Bristol, Avon, England.
    Hall, Jim W.
    Univ Oxford, Environm Change Inst, Oxford, England.
    Page, Trevor
    Univ Lancaster, Lancaster Environm Ctr, Lancaster, England.
    Phillips, Jeremy C.
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Simpson, Michael
    Univ Oxford, Environm Change Inst, Oxford, England.
    Smith, Paul J.
    Univ Lancaster, Lancaster Environm Ctr, Lancaster, England;European Ctr Medium Range Weather Forecasting, Reading, Berks, England.
    Wagener, Thorsten
    Univ Bristol, Dept Civil Engn, Bristol, Avon, England;Univ Bristol, Cabot Inst, Bristol, Avon, England.
    Watson, Matt
    Univ Bristol, Sch Earth Sci, Bristol, Avon, England.
    Epistemic uncertainties and natural hazard risk assessment - Part 2: What should constitute good practice?2018Ingår i: Natural hazards and earth system sciences, ISSN 1561-8633, E-ISSN 1684-9981, Vol. 18, nr 10, s. 2769-2783Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Part 1 of this paper has discussed the uncertainties arising from gaps in knowledge or limited understanding of the processes involved in different natural hazard areas. Such deficits may include uncertainties about frequencies, process representations, parameters, present and future boundary conditions, consequences and impacts, and the meaning of observations in evaluating simulation models. These are the epistemic uncertainties that can be difficult to constrain, especially in terms of event or scenario probabilities, even as elicited probabilities rationalized on the basis of expert judgements. This paper reviews the issues raised by trying to quantify the effects of epistemic uncertainties. Such scientific uncertainties might have significant influence on decisions made, say, for risk management, so it is important to examine the sensitivity of such decisions to different feasible sets of assumptions, to communicate the meaning of associated uncertainty estimates, and to provide an audit trail for the analysis. A conceptual framework for good practice in dealing with epistemic uncertainties is outlined and the implications of applying the principles to natural hazard assessments are discussed. Six stages are recognized, with recommendations at each stage as follows: (1) framing the analysis, preferably with input from potential users; (2) evaluating the available data for epistemic uncertainties, especially when they might lead to inconsistencies; (3) eliciting information on sources of uncertainty from experts; (4) defining a workflow that will give reliable and accurate results; (5) assessing robustness to uncertainty, including the impact on any decisions that are dependent on the analysis; and (6) communicating the findings and meaning of the analysis to potential users, stakeholders, and decision makers. Visualizations are helpful in conveying the nature of the uncertainty outputs, while recognizing that the deeper epistemic uncertainties might not be readily amenable to visualizations.

  • 47.
    Beven, Keith
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Cloke, Hannah L.
    Department of Geography, King's College London, London, UK.
    Comment on ‘‘Hyperresolution global land surface modeling: Meeting a grand challenge for monitoring Earth’s terrestrial water’’ by Eric F. Wood et al.2012Ingår i: Water resources research, ISSN 0043-1397, E-ISSN 1944-7973, Vol. 48, s. W01801-Artikel i tidskrift (Refereegranskat)
  • 48.
    Beven, Keith
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära. Univ Lancaster, Lancaster Environm Ctr, Lancaster LA1 4YQ, England.;Univ Lausanne, IDYST, Lausanne, Switzerland..
    Davies, Jess
    Univ Lancaster, Lancaster Environm Ctr, Lancaster LA1 4YQ, England..
    Velocities, celerities and the basin of attraction in catchment response2015Ingår i: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 29, nr 25, s. 5214-5226Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Catchment systems are interestingly nonlinear, but their dynamics are constrained from being unduly chaotic by mass and energy balance requirements. There have been no attempts in hydrology that we know of that have tried to map both the flow and transport dynamics of a catchment in any form of phase space. In part, this is because of the high dimensionality of the space-time patterns of response; in part because there is sufficient uncertainty about the input and output fluxes estimated by measurement that this might be expected to obscure any attractor-like behaviour. In this study we explore the basin of the catchment attractor for the Multiple Interacting Pathway (MIPs) model that in previous papers has been shown to give good results for the small Gardsjon catchment in Sweden. MIPs is based on particle tracking techniques and gives results for both the flow responses and for the travel and residence time responses of water in the catchment. Here it is used to provide consistent values of fluxes, total storage, travel time distributions and residence time distributions for a long simulation period. The nature of those responses in storage and input dimensions is then investigated. The results suggest that the range of behaviours is hysteretic in interesting ways and constrained by the forcing inputs, with space filling of trajectories in the basin of attraction as should be expected of a forced dissipative system. The range of behaviours exhibited defines a space that the responses of any simpler emulator model will need to span.

  • 49.
    Beven, Keith J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Comment on “Equifinality of formal (DREAM) and informal (GLUE) Bayesian approaches in hydrologic modeling?” by Jasper A. Vrugt, Cajo J. F. ter Braak, Hoshin V. Gupta and Bruce A. Robinson2009Ingår i: Stochastic environmental research and risk assessment (Print), ISSN 1436-3240, E-ISSN 1436-3259, Vol. 23, s. 1059-1060Artikel i tidskrift (Refereegranskat)
  • 50. Beven, Keith J.
    Uncertainty in Predictions of Floods and Hydraulic Transport2007Ingår i: Transport phenomena in hydraulics / [ed] Rowiński, Paweł, Warszawa: Institute of Geophysics , 2007, s. 5-20Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    This paper provides a review of work within the Generalised Likelihood Uncertainty Estimation (GLUE) methodology on estimating uncertainties in predicting flood frequency, flood inundation, and hydraulic transport of solutes in rivers and soils. The issue of prediction uncertainty as an input decision making is also discussed. It is concluded that in real applications it is unlikely that a fully objective approach to uncertainty estimation is possible. It is therefore important that the assumptions made are stated explicitly so that they can be agreed or disputed with the users of the resulting predictions. It is also important that the modelling process be considered as a learning process of constraining uncertainty by adding new information.

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