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Träfflista för sökning "WFRF:(Bishop Kevin) ;pers:(Nyberg Lars)"

Sökning: WFRF:(Bishop Kevin) > Nyberg Lars

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1.
  • Bishop, Kevin, et al. (författare)
  • The hydrology of the covered catchment
  • 1998
  • Ingår i: Experimental Reversal of Acid Rain Effects: the Gårdsjön Project. - : John Wiley & Sons. ; , s. 109-135
  • Bokkapitel (refereegranskat)
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3.
  • Bishop, Kevin, et al. (författare)
  • Water storage in a till catchment. II : Implications of transmissivity feedback for flow paths and turnover times
  • 2011
  • Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 25:25, s. 3950-3959
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper explores the flow paths and turnover times within a catchment characterized by the transmissivity feedback mechanism where there is a strong increase in the saturated hydraulic conductivity towards the soil surface and precipitation inputs saturate progressively more superficial layers of the soil profile. The analysis is facilitated by the correlation between catchment water storage and groundwater levels, which made it possible to model the daily spatial distribution of water storage, both vertically in different soil horizons and horizontally across a 6300-m2 till catchment. Soil properties and episodic precipitation input dynamics, combined with the influence of topographic features, concentrate flow in the horizontal, vertical, and temporal dimensions. Within the soil profile, there was a vertical concentration of lateral flow to superficial soil horizons (upper 30?cm of the soil), where much of the annual flow occurred during runoff episodes. Overland flow from a limited portion of the catchment can contribute to peak flows but is not a necessary condition for runoff episodes. The spatial concentration of flow, and the episodic nature of runoff events, resulted in a strong and spatially structured differentiation of local flow velocities within the catchment. There were large differences in the time spent by the laterally flowing water at different depths, with turnover times of lateral flow across a 1-m-wide soil pedon ranging from under 1?h at 10- to 20-cm depth to a month at 70- to 80-cm depth. In many regards, the hydrology of this catchment appears typical of the hydrology in till soils, which are widespread in Fenno-Scandia. Copyright (c) 2011 John Wiley & Sons, Ltd.
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4.
  • Davies, J., et al. (författare)
  • Integrated modeling of flow and residence times at the catchment scale with multiple interacting pathways
  • 2013
  • Ingår i: Water resources research. - : American Geophysical Union (AGU). - 0043-1397 .- 1944-7973. ; 49:8, s. 4738-4750
  • Tidskriftsartikel (refereegranskat)abstract
    • There is still a need for catchment hydrological and transport models that properly integrate the effects of preferential flows while accounting for differences in velocities and celerities. A modeling methodology is presented here which uses particle tracking methods to simulate both flow and transport in multiple pathways in a single consistent solution. Water fluxes and storages are determined by the volume and density of particles and transport is attained by labeling the particles with information that may be tracked throughout the lifetime of that particle in the catchment. The methodology allows representation of preferential flows through the use of particle velocity distributions, and mixing between pathways can be achieved with pathway transition probabilities. A transferable 3-D modeling methodology is presented for the first time and applied to a unique step-shift isotope experiment that was carried out at the 0.63 ha G1 catchment in Gardsjon, Sweden. This application highlights the importance of combining flow and transport in hydrological representations, and the importance of pathway velocity distributions and interactions in obtaining a satisfactory representation of the observations.
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5.
  • Norén, Viveca, 1972-, et al. (författare)
  • Assessment of Drinking Water Risks Due to Flood – Possibility of Integrating Methods
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • Floods are complex events and it is widely acknowledged that to manage risks associated with such events a holistic approach is needed. Sectors and activities need to cooperate and coordinate activities. Integrated flood management (IFM) is discussed in the literature and is being implemented in practice. To investigate integration between flood management and a sector commonly affected by floods, we have studied risk assessment methods for floods and for drinking water supply in Sweden. We have analysed nine methods provided by agencies or organisations to see how these consider potential effects of floods on drinking water. For the analysis we use a conceptual model of the assessment chain flood – drinking water system – consumer. We explore possibilities of combining methods for flood and drinking water risk assessment to achieve a more integrated assessment.We see that effects of floods on drinking water are considered in the methods but in a general way. Although the flood risk assessment methods investigate the potential exposure of assets, the consequences of this exposure are only included in one method and only for physical impact, not water quality risk.  In the drinking water methods flood is considered as one among many causes of disturbances and not investigated in detail. More detailed analyses of the actual effects of flood on drinking water are needed as well as consequences for the consumers.We believe that it is possible to combine methods for flood and drinking water risk assessment to achieve a more holistic image of relevant risks.
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6.
  • Norén, Viveca, 1972-, et al. (författare)
  • Flood riskassessment – Practices in flood prone Swedish municipalities
  • 2016
  • Ingår i: International Journal of Disaster Risk Reduction. - Uppsala Univ, Dept Earth Sci, Villavagen, SE-75236 Uppsala, Sweden. [Noren, Viveca; Bishop, Kevin] Uppsala Univ, Dept Earth Sci, Villavagen 16, SE-75236 Uppsala, Sweden. [Noren, Viveca; Nyberg, Lars; Bishop, Kevin] Uppsala Univ, Ctr Nat Disaster Sci, Villavagen 16, SE-75236 Uppsala, Sweden. [Hedelin, Beatrice; Nyberg, Lars] Karlstad Univ, Dept Environm & Life Sci, Ctr Climate & Safety, SE-65188 Karlstad, Sweden. [Bishop, Kevin] Swedish Univ Agr Sci, Dept Aquat Sci & Assessment, POB 7050, SE-75007 Uppsala, Sweden. : Elsevier. - 2212-4209. ; 18, s. 206-217
  • Tidskriftsartikel (refereegranskat)abstract
    • Risk assessments are important to ensure efficient and effective flood risk management. Methods and strategies for flood risk assessment are described in the literature, but less is known about how assessments are actually performed. We have studied local flood risk assessments in Sweden by interviewing flood risk managers in municipalities and analyzing documentation of flood risk assessment efforts.There is a large variation between municipalities in how flood risk assessment has been done. The efforts made in association with the EU Floods Directive together with a Government Commission about a flood in Lake Mälaren are the most advanced assessments. Only a few of the municipalities have done comparable assessments. Generally, however, there is a lack of experience and theoretical knowledge about concepts and methods of flood risk assessment in the municipalities. In the assessments studied, the flood it self had been rather well defined in hazard maps. The consequences of a flood had been studied in the larger projects but only by half of the municipalities. It is mainly direct, tangible consequences that have been included. It is mainly the exposure of assets that has been investigated while little attention has been paid to vulnerability. To improve flood risk assessment in Sweden there is a need for knowledge and resources in the municipalities. Prioritization and motivation are needed to actually perform the assessments. National guidelines for may be helpful to guide municipalities in this work and to have more uniform risk assessment.
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7.
  • Norén, Viveca, 1972-, et al. (författare)
  • Significance of EU Floods Directive Risk Management Plans for Drinking Water Supply
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Flood is a threat to safe drinking water supply. To reduce and manage the risks of floods, EU has adopted the Floods Directive. The Floods Directive is linked to and should be coordinated with the EU Water Framework Directive. Securing drinking water supply is an important aspect for management of both water resources and floods. Recently the first cycle of the Floods Directive working procedure was concluded with the establishment of Flood Risk Management Plans (FRMP). We have investigated how the FRMPs made in Sweden consider the potential consequences of flood on drinking water supply as well as if the plans show signs of integration of flood risk management with water resources management and drinking water supply.  Drinking water supply is well represented in the objectives and measures suggested in the FRMPs. However, the knowledge of the consequences of flood on drinking water is poor. Many of the suggested objectives and measures are concerned with providing more knowledge. The plans show an awareness of the importance of coordination and integration with other sectors and actors but there are few signs that integration actually has taken place.
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8.
  • Norén, Viveca, 1972- (författare)
  • When water becomes a threat : Risk assessment and risk management plans for floods and drinking water in Swedish practice
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Water is an essential but vulnerable resource. A shortage of good quality drinking water is a threat to human health and society as a whole. Abundance of water in the form of floods can also be a serious threat which can have consequences for the drinking water supply. To reduce these risks there is a need for systematic risk reduction. In the last decades a risk management approach has been developed in the management of both flood and drinking water risks. This means that a reactive, ad hoc management is being replaced by a more proactive and systematic approach where risks are analysed and evaluated as a basis for prioritising counter-measures. The complex nature of water issues has also made it evident that there is a need for a holistic view of the management, involving a variety of actors and sectors. An integrated management approach to floods and water resources has emerged.This thesis aims to examine how local level risk management, especially risk assessments, of floods and drinking water supply have been or can be performed in practice in Sweden. The existing practices have been characterised in relation to current risk management frameworks. Furthermore, the thesis aims to investigate how the effects of flood on drinking water supply have been considered in risk assessment methods and in flood risk management plans, as well as whether flood and drinking water risks have been considered in an integrated manner. The studies are based on interviews with flood risk managers in Swedish municipalities and Swedish water producers as well as on document studies of risk assessment methods and flood risk management plans.There are large variations between different municipalities and water producers in how, and to what extent, risk assessments have been performed. Some have performed very little, if any, risk assessment while others have worked systematically. The tools used are often those that are promoted by national agencies and are often less advanced than those described in the literature. The risk assessments do not always cover all relevant aspects of the risk and few actors have discussed an acceptable risk level. Flood risk assessments focus mostly on the exposure of objects to flood and investigate the consequences of such an exposure only to a limited extent. The incomplete risk assessments may result in a biased view of the risk which in turn can lead to poor decision-making. The theoretical knowledge about risk management is in many cases low and there is still often a practical approach. Strategic and holistic approaches are mostly lacking.The consequences of flood on drinking water supply are not known in detail and are not considered in detail in risk assessments commonly used in Sweden. There is an awareness of the need to coordinate the management of flood and water resources. However, despite the good intentions regarding integration, there are few signs in the risk assessments and risk management plans that integration is actually occurring.Both the risk management approach and integrated management have started to be implemented in Swedish flood and drinking water risk management. It is however on a basic level and it is still a long way to go. Further guidance and knowledge about risk management as well as commitment from and collaboration among all actors concerned is needed to make this development possible.
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9.
  • Nyberg, Lars, et al. (författare)
  • Soil frost effects on soil water and runoff dynamics along a boreal forest transect: 1. Field investigations
  • 2001
  • Ingår i: Hydrological Processes. - : Wiley. - 0885-6087. ; 15:6, s. 909-926
  • Tidskriftsartikel (refereegranskat)abstract
    • To determine how soil frost changes flowpaths of runoff water along a hillslope, a transect consisting of four soil profiles directed towards a small stream in a mature forest stand was investigated at Svartberget, near Vindeln in northern Sweden. Soil temperature, unfrozen water content, groundwater level and snow depth were investigated along the transect, which started at the riparian peat, and extended 30 m upslope into mineral soils. The two, more organic-rich profiles closest to the stream had higher water retention and wetter autumn conditions than the sandy mineral soils further upslope. The organic content of the soil influenced the variation in frost along the transect. The first winter (1995–96) had abnormally low snow precipitation, which gave a deep frost down to 40–80 cm, whereas the two following winters had frost depths of 5–20 cm. During winter 1995–96, the two organic profiles close to the stream had a shallower frost depth than the mineral soil profile higher upslope, but a considerably larger amount of frozen water. The fraction of water that did not freeze despite several minus degrees in the soil was 5–7 vol.% in the mineral soil and 10–15 vol.% in the organic soil. From the measurements there were no signs of perched water tables during any of the three snowmelt periods, which would have been strong evidence for changed water flowpaths due to soil frost. When shallow soil layers became saturated during snowmelt, especially in 1997 and 1998, it was because of rising groundwater levels. Several rain on frozen ground events during spring 1996 resulted in little runoff, since most of the rain either froze in the soil or filled up the soil water storage.
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10.
  • Nyberg, Lars, et al. (författare)
  • Water transit times and flow paths from two line injections of 3H and 36Cl in a microcatchment at Gårdsjön, Sweden
  • 1999
  • Ingår i: Hydrological Processes. - 0885-6087 .- 1099-1085. ; 13:11, s. 1557-1575
  • Tidskriftsartikel (refereegranskat)abstract
    • To investigate groundwater transit times and flow paths in shallow till soil, within an acidification study at Gardsjon, Sweden, two line injections of Cl-36 and H-3 Were made in groundwater during 1992. The first injection in January, when the two tracers were injected at the same depth, gave tracer transit times from injection line to outlet of some hours due to a runoff event on the first day. The subsequent recession period left a considerable amount of tracer in the unsaturated zone, which had transit times that ranged from weeks to months. Tracer recovery at the outlet was 78% for H-3 and 47% for Cl-36. Cl retention was indicated. The second injection in November, when H-3 was injected at 30 cm depth and 36C1 at 60 cm depth, gave recoveries of 96% for H-3 and 83% for Cl-36. Apart from an advective flow-dependent tracer transport, very fast tracer pulses occurred. The velocities for those pulses were of the order of tens of metres per hour. Highest tracer concentrations were observed in the superficial soil layers, which suggest that these layers were the dominant flow paths. 
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