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  • 1.
    Arheimer, Berit
    et al.
    SMHI, Research Department, Hydrology.
    Andersson, Lotta
    SMHI, Core Services.
    Alkan-Olsson, J.
    Jonsson, A.
    Using catchment models to establish measure plans according to the Water Framework Directive2007In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 56, no 1, p. 21-28Article in journal (Refereed)
    Abstract [en]

    A participatory modelling process (DEMO) has been developed and applied in a 350 km(2) catchment in southern Sweden. The overall goal is to improve the dialogues between experts and local stakeholders by using numerical models as a platform for discussions. The study is focused on reducing nutrient load and on the development of a locally established measure plan, which is requested by the European Water Framework Directive. The HBV-NP model was chosen as it can calculate effects and costs for different allocations of several combined measures in a catchment. This paper shows the impact of including local data in the modelling process vs. using more general data. It was found that modelled diffuse nutrient pollution was highly modified when including local know-how, soft information and more detailed field investigations. Leaching from arable land was found to be 35% higher using more detailed information on for instance, agricultural practices, crop and soil distribution. Moreover, the stakeholders' acceptance of model results and reliance on experts was increased by applying the participatory process and involving stakeholders in the modelling procedure.

  • 2.
    Arheimer, Berit
    et al.
    SMHI, Research Department, Hydrology.
    Andersson, Lotta
    SMHI, Core Services.
    Larsson, M
    Lindström, Göran
    SMHI, Research Department, Hydrology.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Pers, Charlotta
    SMHI, Research Department, Hydrology.
    Modelling diffuse nutrient flow in eutrophication control scenarios2004In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 49, no 3, p. 37-45Article in journal (Refereed)
    Abstract [en]

    The Swedish Water Management Research Programme (VASTRA) focuses on the development and demonstration of tools for more efficient eutrophication control when implementing the EU water framework directive in Sweden. During the first half of the programme, models for nitrogen flow were developed, and at present, similar models for phosphorus are under construction (e.g. HBV-P). The programme is interdisciplinary, and scientists are collaborating in actor-games and focus group evaluations including scenario analysis. The scenarios modelled in VASTRA phase 1, show that (i) changed agricultural practices can be the most effective and-least expensive way to reduce nitrogen transport from land to, the sea; (ii) constructed agricultural wetlands may only have small impact on riverine nitrogen transport in some regions, due to natural hydrometeorological dynamics; (iii) removing planktivorous fish may be an efficient way of reducing the algal concentrations in lakes without the undesired side-effect of increased nutrient load to the down-stream river system. In VASTRA phase 11, one of the highlights will be interdisciplinary scenario-modelling of different measure strategies in a pilot catchment of southern Sweden (Ronne a).

  • 3. Arnbjerg-Nielsen, K.
    et al.
    Willems, P.
    Olsson, Jonas
    SMHI, Research Department, Hydrology.
    Beecham, S.
    Pathirana, A.
    Gregersen, I. Bulow
    Madsen, H.
    Nguyen, V. -T-V
    Impacts of climate change on rainfall extremes and urban drainage systems: a review2013In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 68, no 1, p. 16-28Article, review/survey (Refereed)
    Abstract [en]

    A review is made of current methods for assessing future changes in urban rainfall extremes and their effects on urban drainage systems, due to anthropogenic-induced climate change. The review concludes that in spite of significant advances there are still many limitations in our understanding of how to describe precipitation patterns in a changing climate in order to design and operate urban drainage infrastructure. Climate change may well be the driver that ensures that changes in urban drainage paradigms are identified and suitable solutions implemented. Design and optimization of urban drainage infrastructure considering climate change impacts and co-optimizing these with other objectives will become ever more important to keep our cities habitable into the future.

  • 4. Cederwall, K
    et al.
    Brandt, Maja
    SMHI, Research Department, Hydrology.
    Workshop 6 (synthesis): linking between flood risks and land use changes2002In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 45, no 8, p. 181-182Article in journal (Refereed)
    Abstract [en]

    Land use changes, such as deforestation, are increasing the world's vulnerability to flooding. Detailed knowledge of the local situation is essential for risk assessment and design of effective flood prevention measures and governs the infrastructure and engineering measures implemented. However extreme floods in large catchments can overwhelm both natural capacity and constructed flood management measures.

  • 5. Jonsson, A.
    et al.
    Andersson, Lotta
    SMHI, Core Services.
    Alkan-Olsson, J.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    How participatory can participatory modeling be?: Degrees of influence of stakeholder and expert perspectives in six dimensions of participatory modeling2007In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 56, no 1, p. 207-214Article in journal (Refereed)
    Abstract [en]

    The authors are involved in a project aiming at the development of a methodology for participatory modeling as a tool for public participation in water resource management. In this paper, some examples of different degrees of stakeholder influence in six key dimensions of participatory modeling are identified and discussed. Arnstein's (A ladder of citizen participation. Journal of the American Institute of Planners, 1969, 4, 216-224) critical discussion of different degrees of "real" decision-making power is taken as a point of departure to assess possible degrees of stakeholder influence. Can we as participatory modelers be sure that we are really inviting our research objects to an equal communicative relationship where local perspectives, knowledge and priorities are respected to the same extent as central and/or expert perspectives? This paper presents an approach that could be used as a tool for structured reflection to avoid unreflective tendencies towards expert knowledge dominance and low degree of stakeholders' real influence over the process.

  • 6. Venohr, M
    et al.
    Donohue, I
    Fogelberg, S
    SMHI.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Irvine, K
    Behrendt, H
    Nitrogen retention in a river system and the effects of river morphology and lakes2005In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 51, no 3-4, p. 19-29Article in journal (Refereed)
    Abstract [en]

    The mean annual transfer (loss and retention) of nitrogen in a river system was estimated using a conceptual approach based on water surface area and runoff. Two different approaches for the calculation of water surface area were applied to determine riverine nitrogen retention in four European catchments, ranging between 860-14,000 km(2) in area, and differing considerably in the proportion and distribution of surface waters, specific runoff and specific nutrient emissions. The transfer rate was estimated sequentially as either the mean value for the total catchment, on a sub-catchment scale, or considering the distribution of water surface area within a sub-catchment. For the latter measure, nitrogen retention in larger lakes was calculated separately. Nitrogen emissions modelled with MONERIS and HBV-N were used to calculate nitrogen river loads and compare those with observed loads. Inclusion of the proportion of water area within a sub-catchment improved modelled results in catchment with large lakes in sub-catchments, but not where there was a homogenous distribution of surface waters among sub-catchments.

  • 7.
    Wittgren, Hans B.
    et al.
    SMHI.
    Maehlum, T
    Wastewater treatment wetlands in cold climates1997In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 35, no 5, p. 45-53Article in journal (Refereed)
    Abstract [en]

    The best prospects for successful wetland treatment should be in the warmer regions of the world, but studies in North America and Scandinavia show that wetland treatment may be feasible also in cooler regions. A review shows that the number of wetlands of different types (free water surface, FWS; horizontal and vertical subsurface flow, SSF), treating different kinds of wastewater, is steadily increasing in most parts of the cold temperate regions of the world. The major wetland engineering concerns in cold climates, which are discussed in this paper, are related to: (1) ice formation, and its implications for hydraulic performance; (2) hydrology and hydraulic issues besides ice formation; and (3) the thermal consequences for biologically or microbiologically mediated treatment processes. Energy- and water-balance calculations, as well as thermal modeling, are useful tools for successful design and operation of treatment wetlands, but the shortage of data makes it necessary to adopt a conservative approach. The treatment processes often appear less temperature sensitive in full-scale wetlands as compared to laboratory incubations. Several possible explanations are discussed in the paper: (1) sedimentation playing a significant role, (2) overdimensioning in relation to some constituents, (3) seasonal adsorption (cation exchange) of ammonium, and (4) temperature adaptation of the microbial community. Experience shows that cold climate wetlands can meet effluent criteria for the most important treatment parameters. To gain wide acceptance, however, we need to become more specific about design and construction, and also about operation, maintenance and cost-effectiveness. These goals require detailed knowledge about processes in full-scale wetlands, including long-term changes and response to maintenance. (C) 1997 IAWQ.

  • 8.
    Wittgren, Hans Bertil
    et al.
    SMHI, Research Department.
    Arheimer, Berit
    SMHI, Research Department, Hydrology.
    Source apportionment of riverine nitrogen transport based on catchment modelling1996In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 33, no 4-5, p. 109-115Article in journal (Refereed)
    Abstract [en]

    Source apportionment of river substance transport, i.e. estimation of how much each source in each subbasin contributes to the river-mouth transport is a vital step in achieving the most efficient management practices to reduce pollutant loads to the sea. In this study, the spatially lumped (at sub-catchment level), semiempirical PULSE hydrological model, with a nitrogen routine coupled to if was used to perform source apportionment of nitrogen transport in the Soderkopingsan river basin (882 km(2)) in south-eastern Sweden, for the period 1991-93. The river basin was divided into 28 subbasins and the following sources were considered: land leakage from the categories forest arable and ley/pasture; point sources, and; atmospheric deposition on lake surfaces. The calibrated model yielded an explained variance of 60%, based on comparison of measured and modelled river nitrogen (Total N) concentrations. Eight subbasins, with net contributions to the river-mouth transport exceeding 3 kg ha(-1) yr(-1), were identified as the most promising candidates for cost efficient nitrogen management. The other 20 subbasins all had net contributions below 3 kg ha(-1) yr(-1). Arable land contributed 63% of the nitrogen transport at the river mouth and would thus be in focus for management measures. However, point sources (18% contribution to net transport) should also be considered due to their relatively high accessibility for removal measures (high concentrations). E.g., the most downstream subbasin, with the largest wastewater treatment plant in the whole river basin, had a net contribution of 16 kg ha(-1) yr(-1). This method for source apportionment may provide authorities with quantitative information about where in a river basin, and at which sources, they should focus their attention. However, once this is done, an analysis with higher resolution has to be performed in each of the interesting subbasins, before decisions on actual management measures can be taken. Copyright (C) 1996 IAWQ.

  • 9.
    Wittgren, Hans Bertil
    et al.
    SMHI, Research Department.
    Tobiason, S
    Nitrogen removal from pretreated wastewater in surface flow wetlands1995In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 32, no 3, p. 69-78Article in journal (Refereed)
    Abstract [en]

    The wastewater treatment plant in the town of Oxelosund (12,500 inhabitants), Sweden, has mechanical and chemical treatment for removal of BOD and phosphorus. With the aim to achieve 50% nitrogen removal, a surface flow wetland system of 21 ha was created as a final step during 1993. It consists of 5 cells, where 2+2 are operated in parallel with a final common cell, This allows intermittent filling and emptying, the goal of which is to promote both nitrification and denitrification for a design flow of 6000 m(3) day(-1). During the first year of operation, August 1993 to July 1994, the wetland removed 720 kg ha(-1) of total nitrogen from the load of 1810 kg ha(-1). Ammonium-N was the dominant fraction at the inlet as well as at the outlet, 79% and 90% of total nitrogen, respectively. The large fraction of NH4+ at the outlet showed that nitrification was the limiting step. An intensive monitoring effort in May 1994 indicated that neither wastewater toxicity nor oxygen deficiency were likely to limit nitrification. Instead, sub-optimal hydraulic loading conditions; a lack of suitable surfaces for ion exchange of NH4+ as well as for attachment of nitrifiers; and phosphorus deficiency, were considered potentially important factors in limiting nitrification. In addition to nitrogen removal, the wetland system reduced total phosphorus, BOD7 and E. coli (44 degrees C) to very low levels at the outlet.

1 - 9 of 9
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  • harvard1
  • ieee
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  • vancouver
  • Other style
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